Transplantation of ipsilateral canine ulna as a vascularized bone graft for treatment of distal radial osteosarcoma
Corresponding author :
Dr. Vladislav Zlatinov,
Central Veterinary Clinic
Chavdar Mutafov str, 25 B, Sofia, Bulgaria
This case report describes the successful use of a vascularized cortical autograft from the ipsilateral ulna in limb-sparing surgery for the treatment of distal radial osteosarcoma. A pancarpal arthrodesis with two orthogonal plates was performed to stabilize the site. No implant failure and local tumor recurrence were observed in the 6 months post operative period. Excellent limb function was achieved within 6 weeks after surgery; no external support (coaptation) were used during the post operative period. Excellent perceived quality recovery, was reported by the dog’s owners, compared to their preliminary outcome expectations.
Osteosarcoma (OSA) is the most common primary bone tumor in dogs, most commonly affecting the distal radius. Current treatment protocols-Fig.1 are based on a combination of surgery (limb amputation or limb sparing surgery) and adjuvant chemotherapy. Palliative therapies like- Stereotactic radiation or Percutaneous
Cementoplasty therapy are rarely applied with limited success 1,2.
Recently, numerous publications suggest that the Limb-sparing surgery is a viable alternative to limb amputation in selected cases, especially indicated if there is pre-existing orthopedic or neurological disease or if owners are resistant to limb amputation 3,4,5,6.
Limb- sparing consists of removing the segment of bone involving the primary tumor and using internal or external fixation to the remaining bones with or without segmental bone replacement, resulting in a salvaged functional limb 7. Limb- salvage procedures
have been described in the distal aspect of the radius, proximal humerus, distal tibia, and proximal femur in dogs with OSA, but the salvage surgery of the distal aspect of the radius has produced the most favorable results. This is mainly because pancarpal arthrodesis is well tolerated by dogs, not like fusion of other joints. Importantly – the prognosis for survival is the same with amputation or limb- sparing, unless an infection is present, in which case the average survival is prolonged.
Candidates for limb sparing
Good surgical candidates are dogs with OSA confined to the bone, with minimal extension into adjacent soft tissue and involving less than 50% of the bone length. The extent of bone involvement is most accurately determined by using computed tomography and is overestimated by radiography, nuclear scintigraphy, and magnetic resonance imaging 8. Pathologic fracture is a relative contraindication for limb-sparing because of tumor seeding into adjacent soft tissue, although the risk of local tumor recurrence can be reduced by use of preoperative chemotherapy or radiation therapy.
Limb sparing techniques
Historically, the most commonly performed limb sparing technique for the distal radial site involved the use of an allograft (donor from an individual of the same species) to replace the bone defect created by segmental bone excision 9- Fig.2. Although the limb function is good to excellent in about 80% of dogs with the allograft technique, the complication rate is substantial. The most common complications include infection, implant related problems, and local recurrence. Infection rate is reported to be up to 60%, implant failure in up to 50% as well. Even more, there are practicality issues for the regular application of the allograft technique- time consuming and costly maintenance of a bone bank. Recently, there is a new alternative for graft purchasing from a commercial source on a case by case basis.
It’s not surprising that alternative limb-sparing methods are being investigated. Reported grafting techniques include pasteurized/ irradiated autografts, endoprosthesis, vascularized ulnar transposition graft (roll-over technqique), free microvascular ulnar autograft.
Nevertheless the technical evolution of the available techniques, all of them are still often associated with a high complication rate including infection, construct failure, and tumor recurrence. The longitudinal or transverse bone transport osteogenesis has the advantages to lower the aforementioned complications but still have limitation for routine implementation in the practice 10, 11.
The advantages and disadvantages of the recent innovative techniques are shortly summarized below.
The most prominent advantage of the endoprosthesis limb salvage (Fig.3) is the simplicity compared to the other grafting techniques; consequently it is time-saving. Decreasing the surgery time may suggest lower infection ration. Unfortunately this was not proved by the clinical experience with the currently commercially available endoprosthesis.
A recent study 4, comparing the results of Cortical Allograft and Endoprosthesis techniques, suggested surgical infection of 60 and 55% of the cases, respectively. The use of a large volume of implants and foreign material has been proposed as a cause. More over in the same study, long term implant failure occurred in 40% of the treated dogs.
A positive remark in the paper is the good (subjectively) limb function, reported in the stable phases or in non-complicated cases.
A more biologic friendly technique- ulnar roll-over – Fig.4 was resently reported with good results, despite limb shortening of up to 24 % 3,12,13. The distal ulna is osteotomized, rolled into the radial defect, and secured with a bone plate and screws. With this technique the preservation of the caudal interosseous artery and vein and a cuff of the deep digital flexor, abductor pollicis longus, and pronator quadratus muscles are important for maintaining viability of the transplanted ulna.
Theoretically, using a vascularized bone graft could reduce the gross incidence of complications compared to an allografts or endoprothesis. Vascularized bone is more resistant to infections, to the extent that vascularized cortical autografts have been used to treat osteomyelitis. Also the use of a viable graft may preserve biomechanical properties over allografts. Whereas the allograft may resorb and become weaker over time, the ulnar graft may maintain its physical properties or even hypertrophy and healing with the host bones.
However, the statistics reports are controversial, with no clear proof for substantially better outcomes. One study shows no statistically different infection (45%) and implant failure (55%) ratio. Probably the presence of a viable graft does not address all other factors predisposing to infection (poor soft tissue coverage, immunosuppression from neoplasia and chemotherapy, and use of orthopedic implants). The other complication problem- implant failure, sounds as a surgeon’s skills dependent issue. For example one of the major complication in the mentioned study has been fracture of the remaining radius in cases of great length resection (>57%), which could be just consequence of suboptimal plate length or screws number and distribution.
Importantly, the roll-over technique demands sufficient length of the distal ulna to be preserved, but local recurrence was not increased compared to other limb- sparing techniques.
Microvascular anastomosed bone transfer was used in the presented case. This is a routine procedure in the limb sparing surgeries in human patient, but rarely applied technique in veterinary medicine, nevertheless, the vascular supply of the distal ulna has been , studied, described and successfully used experimentally and clinically 14,15.
In this technique, a more substantial middiaphysis segment of the ipsilateral ulna, with its source artery and vein (the common interosseous) is harvested and transpositioned, with a blood supply restored by vascular anastomosis to a neighboring artery and vein, once the graft is in its new position. The surgical technique is described further in the text. The concept is the same as the ulnar roll-over but, with the advantages of stronger cortical ulnar graft used, more mobile graft and a chance for full distal ulnar resection. The disadvantages of this procedure are the need for a specially trained and equipped microvascular team and the prolonged surgical time.
Longitudinal bone transport osteogenesis
This is a specific application of distraction osteogenesis, which has been used successfully in dogs for replacement of large segmental defects of the distal aspect of the radius and tibia after tumor resection. This is a process whereby healthy, detached bone segment is sequentially moved across an adjacent segmental osseous defect forming new regenerate bone in the distraction gap -Fig.5.The regenerate bone is highly vascular and resistant to infection.
The results following the procedure have been very encouraging, with good orthopedic function and no reported infections. Disadvantages of the bone transport osteogenesis procedure is the significant amount of time required to fill the defect after tumor removal (up to 7 months). This often leads to owner compliance issues (distracting the apparatus two to four times per day), also pin-tract drainage and loosening, difficulty in docking the intercalary bone onto the radial carpal bone.
A recent modification –Transverse Ulnar Bone Transport Osteogenesis, has been reported 16- Fig.6. The technique substantially decrease distraction times. In one case report, distraction of the ulnar transport segment across the 84 mm longitudinal segmental radial defect, was completed in 23 days.
A 9-year-old female Rottweiler dog (43 kg) was referred to our practice with a 3- weeks history of left forelimb lameness with an gradual onset and an unknown origin. The dog was been previously prescribed NSAIDs with temporary effect. During our examination we found weight-bearing lameness II/V. Physical and orthopedic examination revealed distal radial swelling on the left forelimb, with pain on extension of the carpal joint.
Orthogonal radiographs were achieved, revealing vast osteolytic (relatively smooth margins) area in the distal radius, with no apparent lesions in the distal ulna- Fig.7
Based on the history, signalment, lesion location, and radiographic findings, a primary bone tumor was suspected.
No abnormalities were detected on preoperative 3-view thoracic radiographs, abdominal ultrasound, echocardiography, and blood tests- Fig.8. The Alkaline Phosphatase (AP) value was 195 U/L- in the upper limit but still within the reference range for the breed.
Treatment options were discussed with the owners:
-conservative palliative treatment
-amputation and chemotherapy
-limb-sparing surgery in conjunction with chemotherapy;
The owners chose the last course of treatment but insisted on preoperative histologic confirmation of the suspected diagnosis.
After short anesthesia and minimal invasive approach, tissue biopsy sample was retrieved and send for analysis. Ten day later the the suspicious of osteosarcoma neoplasia was confirmed. The histologist comments were: moderately aggressive OSA with low mitotic figures. Meanwhile the dog showed acute lameness deterioration, related to a pathological fracture of the cranio-distal cortex of the radius, following the biopsy procedure- Fig.9.
A limb sparing procedure (roll-over vs. free vascularized) grafting was planned.
Twenty minutes before the skin incision high segmental epidural analgesia wad accomplished at the level of T11, infusing 2 ml of 0,25 % Levobupivacian solution and positioning the patient in left lateral recumbency for 10 minutes- Fig. 10.
For the surgical intervention, the dog was positioned in sternal recumbency- Fig 11. , facilitating a dorsal approach to the radius and carpus. Careful tissue examination was done during the sharp dissection of the distal soft tissues. Caudally, the tumor was closely attached to the distal ulna. Thus, the tumor was not dissected caudally to avoid contamination. A decision for a more extending distal ulnar resection was made. This prevented the option for roll-over technique more advanced free vascularized transfer was prepared.
The extensor carpi radialis muscle was transected proximal and distal to the tumor; the common and lateral digital extensor tendons were spared. An oscillating saw was used in both radial and ulnar osteotomies. The level of the transverse osteotomy of the radius, 2 cm proximal to the tumor, was determined on radiographs and confirmed appropriately intraoperatively. The ulna was osteotomized at lower level, just over the overlapping zone with the radius. The radius was disarticulated at the antebrachiocarpal joint and the tumor removed en bloc with the distal ulna. The length of the resected radial segment was 10 cm, including the 2-cm free margins (this represented 45% of the total radial length). The whole radio-ulnar segment was stored in 10 % formalin solution for later histologic analysis-Fig.12 and 13
After tumor removal the limb sparing was continued with cartilage debridement from the carpal and metacarpal bones , accomplished by using a speed burr drill; several penetrating drill holes were created in dorsal surface of the radial carpal bone.
The resected radial bone segment was measured and a second ulnar osteotomy performed proximally using a separate blade to match the length of removed radial bone minus 1,5 cm. The proximal ulnar osteotomy was performed above the level of the radial osteotomy while identifying and carefully dissecting the caudal interosseous artery and vein.The last were a-traumatically clamped and transected as proximal as possible, preserving as much as possible of the vessel length.The muscle attachments of the abductor pollicis longus, ulnar head of the deep digital flexor, and pronator quadratus were kept intact onto the periosteum of the distal aspect of the ulna.
The ulnar graft was transposed into the radial defect and the proximal end of the common interosseal artery (<2 mm) was anastomosed to a distal branch of the median artery. The anastomosis was accomplished with the use of magnification (10x) with surgical microscope and fine jewelers forceps- Fig.14 and 15. General principles of end-to-end vascular anastomosis were followed- atraumatic handling, distance of 0,5- 1 mm from the vascular wound’s edge, the regular suture distance, etc. Five interrupted sutures (8-0 nylon) were used to seal the anastomosis. The total ischemic time of the bone graft was about 60 minutes.
The microanastomosis success was confirmed by identification of a active blood flow present in the graft’s tissues and the distal end of the interosseal artery (video 1 ). The corresponding vein was not anastomosed, but its end was left free in the surrounding soft tissues. The distal artery ending was ligated.
After the anastomosis, the procedure was finished by stabilization of the bone graft by long plate, engaging from the distal metacarpal bones to the proximal radius, on the cranio-dorsal surface. We used hybrid 4,5 mm plate (Mikromed, human series) allowing fixation with 4,5 mm screw proximally, 3,5 mm in the middle area (free graft) and divergent 2,7 mm screws in the III and IV metacarpal bones. A second orthogonal plate 3,5 mm reconstructive locking (Mikromed) was applied laterally, fixating the proximal radius to the fifth metacarpal bone- Fig.16 and 17. Copious cancellous bone graft (from proximal humerus) was retrieved and stacked at the level of all osteotomy gaps.
After copious wound lavage and before closing of the surgical wound, the implants were covered by Gentamycin impreganted bovine collagen sponges (Gentacoll- resorb). The goal of the last was infection prevention. A soaker catheter was also inserted along the full length of the surgical wound. Subcutaneous tissue and skin were closed routinely. After skin suturing, the leg was bandaged with modified Robert -Jones bandage for the next 12 hours. The soaker catheter was attached to elastomeric pump, delivering 1 % Lidocain solution – 5 ml/h, for the next 3 days.
Post operative care
Postoperative analgesia consisted of: local Lidocain flash block delivery by the elastomeric pump (36 h) , Butorphanol (0.3 mg/kg, every 6 h, i.v.) and meloxicam (0.1 mg/kg /24h ,s.c.).
Cryotherapy (frizzed towels compresses) was applied every 4 hours for the next 48 h- Fig. 18
Cephazolin (20 mg/kg/8 h, i.v.) was applied for 3 days post op.
On the third post operative day -the dog was discharged, with oral Cimalgex (Cimicoxib, 2 mg/kg/day) for 14 days. Oral amoxicilin clavulonic acid (12,5 mg/kg/12h) was administered for 2 weeks and exercise was restricted to short walks on a leash for 12 weeks. The dog was re-examined regularly- every 14 days, including the visits for the chemotherapy sessions.
The histopathological diagnosis of the excised bone confirmed a grade II fibroblastic osteosarcoma (OSA)– Fig. 19. Surgical resection was considered complete with no evidence of neoplasia at joint compartment.
A single agent protocol -carboplatin (300 mg/m2)- Fig. 20, was planned and applied every 3 wk for a total of 5 treatments. The first treatment was started 2 weeks after surgery. A CBC was taken 2 weeks after and just before each carboplatin administration; serum biochemistry was performed every 2 months. There was no evidence of gastrointestinal upset, renal failure or myelosupression after chemotherapy. The AP levels were always in the reference range.
Clinical recovery and Follow up
Lameness progressively improved from toe-touching (one day after surgery) to full weight-bearing with only slightl visible lameness- 6 weeks post op. No external coaptation was applied during the recovery period- Fig.21, Video 2- 3.
Six months post op the limb function was appreciated as excellent, without any significant changes on limb palpation- Fig.22. Video 4. Orthogonal radiographs were taken, showing proximal bone fusion; distally the bone was superimposed by the lateral plate. No signs of construct failure were observed. A decision for dynamisation was made and the lateral plate was removed, revealing radiographically the bony structure under it. It showed good bone density and excellent graft fusion (primary), proximally and distally. Further segment hypertrophy is expected by the increased load sharing.
The limb sparing surgery could be a viable option for treating distal radial OSA in properly selected cases. With the innovative alternatives, the widely accepted approach to canine OSA – limb amputation treatment, should not be applied as “default treatment” in each case. Case to case individual approach may provide the pets and their owners more fare attitude. Excellent functional results of the limb may be achieved by a complex (but single stage) surgical segment resection and appropriate bone reconstruction and rigid fixation. The use of free vascularized bone graft is a manageable option and an alternative to ulnar-roll over in cases of distal ulnar tumor engagement or vast radial segments resection, where solid vascular bone grafting is demanded.
Disc herniation is a neurological disorder that is characterized by slipping nucleus pulposus outside of the space between the bodies of two vertebrae, the clinical appearance of intense pain in the area. Practical part or whole kernel pulposus (soft area of the intervertebral disc) herniates through a weakened area of the intervertebral disc annulus. Disc herniation can occur at any level of the spine, but the two most common sites are the lumbar and cervical. To establish a diagnosis of certainty indicated imaging studies: x-rays, CT, MRI, myelography. Nuclear magnetic resonance (NMR) is much more appropriate than CT in diagnosing pathologies of the spine. The obtained images are three-dimensional and thus very well both visualization column and nerve roots, and can determine the disease itself. Currently, MRI is the imaging method for diagnosing first intention herniated disk and can even be used in patients who have no clinical symptoms.
A 4 years old male, boxer weighting 24kg was present to us, after 14 days of tetraplegia; the debut being 6 months ago when it started difficult and heavy lifting from the bottom, neck pain when the steroid anti-inflammatory drug was administrated, the symptoms were resolved; 14 days ago tetraplegia was installed.
The animal presents a normal body temperature, its respiratory and cardiac frequency is within normal values, biochemical parameters and blood results is not modified. Neurological tests point out the tetraplegia, with persistence of profound sensibility and the absence of superficial sensibility. After neurological examination were also present: abolished patellar reflexes, flexor reflex abolished, tibial reflex abolished, absence correctional reaction, panicular reflex abolished , anal reflex present globe bladder.
An MRI was done at the Telescan, Timisoara, which pointed out a extrusion of the intervertebral C2-C3 (fig. 1/2).
Cervical Herniated Disc C2-C3
- Surgical Procedure
Surgical technique: ventral corpectomy, herniated disc extraction.
The dogs were anesthetized with a mixture of ketamine and xylazine (10 mg/kg and 15 mg/kg i. m.), Propofol (2 mg/kg) and artificially ventilated by a respirator with oxygen and monitored.
After trimming antisepsis field operator and 10% betadine solution, and took the subconjunctival tissue and skin incision, incision between the vertebrae C1-C4 (fig. 3)
After removing sternocephalic muscle, inferior thyroid artery is highlighted, (Fig 4/5) muscle sternohyoid that close side of trachea, esophagus, carotid, highlighting recurrent laryngeal nerve and muscle along the neck (Fig. 6)
The latter is detached the ventral tubercle of the affected disc space, resulting in highlighting the ventral face of the ring disk.
Discuss ring incision rise to the spinal canal, then extract the affected disc (Fig.7)
Hemostasis was secured with ultra incision Harmonic Scalpel(Fig.8)
- After surgery
Postoperative treatment containing corticotherapy 5 days, antibiotherapy 5 days and a bladder catheter the first 24 hours.
Surgery is commonly recommended on dogs that do not respond to medical treatment, have progressive clinical signs, or have more severe neurological deficits.
The efficacy of medical therapy may only be seen in patients that have minimal neurological deficits.
- After surgery evolution of the clinical case has been very good.
- 72 hours postoperative, the patient is able to move without any help. (Video)
- After two months postoperative the animal is completely healed, and does not manifest any neurological symptoms.
- The success rate with surgery is generally high provided that the spinal cord hasn’t been compressed for a long time (chronic spinal cord injury). Chronic cord injuries can be treated successfully with surgery, but the outlook is less favorable than it is for short-term (acute) injuries.
Veterinary Clinic Blue Cross
Case presentation: a 3 and a half year old female pug dog was presented at the Bluecross Veterinary Clinic in Sofia for additional diagnostics in view of resently started seizure events.
A month ago the dog started having problems with its hind left limb and another vet started him on prednisolone. The limping improved but 20 days later the dog started having seizures.
The patient was examined at the Bluecross Veterinary Clinic in Blagoevgrad within two hours after one of the seizures. At that stage the dog wasn‘t able to see properly and showed a tendency to circle to the left. Blood was taken for Cbc and biochemistry analysis and the results were normal. The patient was started on an antiepileptics drug – Phenobarbital and the steroids were continued (because of the high possibility of an inflammatory process). An examination at the clinic in Sofia and additional advance imaging were scheduled.
good general condition, slight difficulties in breathing (because of the brachiocephalic syndrome), normal heart and lung sounds, normal temperature.
Neurological examination: a little overexcited behaviour (but it was impossible to tell if this behaviour was abnormal for the dog or not). Normal cranial nerve reflexes, no nysgmus or circling, normal pupillary light reflexes. There was slight spinal ataxia in all four limbs. The proprioceptive tests were normal on all four. On the hind left limb the dog has pattelar luxation second degree (this explains the limping epizode a month ago). From the video provided by the owner it could be observed that the dog was demonstrating clonic- tonic seizure.
The owner was questioned for possible toxins, drugs and plants that could be the reason for the seizures but he said that the dog couldn’t have eaten anything abnormal.
A forebrain lesion was localised but the possibility of a multifocal process was very high.
The blood results were normal; therefore, possible extracranial reasons for the seizures were excluded. Toxin exposure was excluded by the anamnesis.
The list of differential diagnoses was:
- Inflammatory process – Necrotizing Meningoencephalitis (NME or Pug encephalitis)
- Idiopathic epilepsy
- Brain neoplasia
- Congenital lesion- hydrocephalus, cysts
To exclude most of the diagnoses from the list, advance imaging was performed – MRI 1,5tesla was used. The test was done with and without contrast material.
On the MRI we discovered a bilateral enlargement at the cranial part of both lateral ventricles within the frontal lobe of the brain. There was a visible communication between the ventricles and the subarachnoid space at the level of the eyes. They looked like cystic lesions filled with CSF. Bilateral loss of brain tissue was observed in both hemispheres. Around the cavities the cerebral cortex was reduced. These bilateral lesions could explain all the clinical signs that this dog was showing – seizures and the ataxia of all four limbs. There are motor cortex within the frontal lobe of the brain. There was no contrast enchantment after injection of contrast material within the brain tissue.
Therapeutic plan: the dog antiepileptic treatment was continued and regular measurements of the level of phenobarbital were scheduled. I added proton pump inhibitor –Esomeprazole (S enantiomer of omeprazole) because the drug has the effect of reducing the cerebrospinal fluid production. The steroids are slowly taped and they will be discontinued after two weeks.
The dog’s condition will be monitored by the owner and the vets at the BlueCross Veterinary Clinic in Blagoevgrad. In case of progression, especially after we stop the steroids, the necessity to take a CSF sample in order to finally exclude an inflammatory process is being discussed with the owner.
Porencephaly is a rare congenital cerebral defect and it is described in several reports in the field of veterinary medicine. It is more commonly seen in ruminants but there are few reports about dogs and cats.
There are few cystic congenital lesions of the brain, including focal lesions (porencephaly), extensive lesions (hydranencephaly) and very rarely schizencephaly (more commonly seen in humans). In porencephaly the defect creates a communication between the lateral ventricles and the subarachoid space. In schizencephaly the defect may be surrounded by a ring of polymicroglia. The schizencephalic defects are lined by gray matter.
The most frequent classification of these lesions based on their pathogenesis divides these defects into two major categories: developmental and encephaloclastic. Developmental porencephaly is due to a focal neuronal migration disorder, leaving a gap in the developing cerebral hemisphere. Encephaliclastic porencephaly includes cerebral cavities that result from tissue breakdown of various etiologies (cerebral ischemia, infection, trauma). In utero infection is the most common reason, especially in ruminants.
The interesting thing is that this type of lesions are congenital in nature but the clinical signs can start after the birth of the animal (which should be expected from the age) or sometimes later in life (after a few years).
According to the few reports about this type of pathology, the progression of the disease is different in every case. Some of those are completely asymptomatic, other cases are well controlled with drugs (antiepileptic drugs) third – their condition worsened, with poor control on drugs and some of those were euthanized. There was one report on a case of hydranencephaly where a ventriculoperitoneal shunt was placed and the dog’s condition slightly improved. Therefore, this is also a therapeutic option in some of those severe cases.
- Porencephaly and cortical dysplasia as cause of seizures in a dog: Gisele Fabrino, Maria-Gisela Laranjeira, Augusto Schweigert and Guilherme Dias de Melo BMC Veterinary Research 2012
- Porencephaly and hydranencephaly in six dogs: Davies ES1, Volk HA, Behr S, Summers B, de Lahunta A, Syme H, Jull P, Garosi L. Vet Rec. 2012 Feb
- Porencephaly in dogs and cats: Magnetic resonance imaging findings and clinical signs: Schmidt MJ1, Klumpp S, Amort K, Jawinski S, Kramer M. Vet Radiol Ultrasound. 2012
- Porencephaly in dogs and cats: relationships between magnetic resonance imaging (MRI) features and hippocampal atrophy: Ai HORI, Kiwamu HANAZONO, Kenjirou MIYOSHI and Tetsuya NAKADE, J Vet Med Sci. 2015
Dr Dimitar Ivanov,
Veterinary surgeon, Neurology specialist
Dobro hrumvane veterinary clinics
Dog, Bleki, toy terrier, M, 5 yo.
Came in the clinic on 11.04.2017 with left circle movements, menace deficit on the left and no reaction when stimulating the nasal mucosa. On the right, spinal reflexes are decreased and there are no conscious proprioception.
Doubt for brainstem problem.
V – vascular – it’s with peracute onset
I – inflamatory – it’s possible but no changes in blood sample
T – toxic – The dog did not take any medication, fed the same food and was not seen taking unusual things, but it’s not unpossible
A – anomalous – тhe dog is 5 years old and it is unlikely that there will be any manifestation of these diseases
M – metabolic – there is no other clinical signs or any changes in blood samples.
I – idiopathic – there is no seizures and vestibular signs
N – neoplastic – it’s more possible
D- degenerative – the dog is too young for cognitive dysfunction and too old for other degenerative diseases.
We made MRI on 12.04. and found a lesion in the left mesencephalon.
The final diagnosis is neoplasia in left midbrain.
We started to prepare for surgery.
The antibiotic preoperative was Ceftriaxone 30 mg/kg i.v., Manitol 1 g/kg i.v. and Methylprednosolone 20 mg i.v.
The surgery was on 22.04.2017 and we made a left craniotomy and displacement of the temporal lobe dorsolaterally until the lesion was reached.
Bleki preoperative video:
The skull was open and we enlarged the hole with Kerrison rongeur (pic 1 and 2)
We aspirated the brain liquor and very slowly reverse the left temporal lobe.( Pic 3 and 4)
When we found the lesion we punctured the cyst formation and drew the liquid contents.( pic 5)
The reason to do this surgery was to try to reduce the pressure in the tissue and to improve the dog’s condition.
After surgery we continued the antibiotics in the same dose and methylprednisolone in the same dose for three days. After then the dose was reduce to 2 mg /kg. After few days the methylprednisolone was change with prednisolone and started to reduce the dose.
Until the methylprednisolone is reduced, the patient is better every day, improves motor activity, appetite, but fails to maintain a constant temperature. A corneal ulcer of the left eye appears – I guess the cause is a trauma to the left oculomotor nerve and reduced lacrimation.
On 28.04. we included one more antibiotic – amoxicillin with clavulonic acid.
On 29.04. the prednisolone was reduced to 0,5 mg/kg, the dog was with anisocoria (myosis on the right eye and mydriasis on the left). On 30.04. the circle movements on left started again.
We tried to find Lomustine for chimiotherapy but we couldn’t and increased the dose of the prednisolone to 2 mg/kg
Bleki 22 days after surgery:
Bleki 23 days after surgery
The dog is good, he walk normally but when he stops, he start to make circle movement on the left.
- Loncar, DVM1
- Hadzic, DVM2
1,2 Department of Orthopedic Surgery and Neurology, Veterinary Clinic Novak, Belgrade, Serbia
An 8,5 years old miniature schnauzer dog was presented at the clinic with finding of right hind limb monoparesis and grade 1 lameness. CT diagnostic study was done but it was suggested that there was no visible lesions. MRI study shoved a lesion consistent with PNST. The dog was treated surgically and the tumor was excised completely with large margins. The dog recovered completely. The purpose of the article is to suggest that a lesion consisted with PNST distal to the stifle an elbow can be treated with large margins and very good motility of the limb afterwards. This type of pathology can be often missed with orthopedic conditions.
A 10 kg BW, 8,5 years old miniature schnauzer was presented at the clinic with owners complain of lameness on right hind limb for last five months.
At previous vet the dog was submitted to complete orthopedic, radiography and CT study with no diagnosis after the diagnostic workout. The dog was treated with 20 days of NSAID therapy (carprofen 2mg/kg BID 10 days and the dosage was reduced by half for the next 10 days). There was no improvement so the dog was treated with prednisolone for 20 days SID with again very little improvement.
The dog doesn’t have any important data in medical history.
At the presentation in our clinic:
During the walk dog showed grade one lameness.
At the clinical examination the dog showed normal proprioception but reduced withdraw reflex on right hind limb. During palpation region of gastrocnemius muscle was markedly painful. The rest of nurology and orthopedic examination was in within normal limits.
Figure 1. and 2.
There is a focal dilation of a vascular structure, presumably a vein, caudal to the medial aspect of the right stifle. The vascular dilation/aneurism has a maximal diameter of 7.7 mm and extends over a distance of approximately 4 cm. Contrast filling of the dilated area is heterogeneous with some areas lacking contrast filling. The affected vessel is an anastomosis/branch between the caudal branches of the saphenous vein and the caudal proximal femoral vein.
Figure 3. T1+contrast: On the right limb at the level of tibial nerve there is a lesion with heterogeneous contrast intake in long contact with blood vessel. The lesion is 3 cm long in diameter.
Figure 4. T1+contrast: Lesion at the level of tibial nerve in close contact with saphenous vein and the caudal proximal femoral vein. Heterogeneous contrast intake.
The surgical approach was made from medial side at the level of proximal part of gastrocnemius muscle. The careful identification of blood supplies and nerve structure was needed. The healthy proximal and distal part of the nerve was identified and the excision with 3 cm margins has been done.
The dog was treated post operatively with antibiotics for 7 days (cephalexin 15mg/kg BID), fentanyl patch for 3 days, carprofen 2 mg/kg BID for 7 days, gabapentin since 3th day 20 days 10mg/kg TID.
Neurological exam has been done after 1,3,6 and 12 months. The only abnormal finding 6 and 12 months post op was longer ground phase during walk and reduced withdraw reflex.
Tibial nerve is in charged for the motor function of caudal aspect of tibia and fibula. Deficit in function shows clinical signs that look similar to orthopedic conditions. Ground phase is longer, calcaneus drops distally more than in contralateral limb. Sometimes we can see plantigrade stance. Orthopedic conditions similar to these in term of signs are pathology of Achill’s tendon and tarsus and metatarsus.
PNST if at the distal part of peripheral nerves can be treated with good outcome. The reasons are fewer functions that lead in less of dysfunction of the limb, and good surgical margins. If PNST is localized at plexus or nerve root, 78% of dogs are going to be euthanized. The prognosis depends on localization and histopathology grading.
This article shows how close sometimes can be neurology and orthopedic clinical findings. Even if advanced imaging is available the cruciate information is localization of the lesion during the clinical examination. Further a right interpretation of images is necessary to define the lesion. PNST is an important differential diagnosis in investigation of distal extremities dysfunctions.
Marko Novak, dvm
Department of Orthopedics and Neurology
Klinika Loka, refferal small animal clinic, Škofja Loka, Slovenia
Luna is a lively 1,5 year old German Boxer, weighing 28 kg. She was presented to us with chronic intermittent right front leg lameness of grade II lasting for almost a year. Her owners noticed a lump on her medial carpal site. The dog had a history of a car accident when she was only six months old. At that time Luna was treated conservatively with NSAIDs and rest. Luna became worse after time and she was reffered.
Carpal joint is a hinge joint. It is composed out of six carpal bones that are arranged in a proximal and distal row forming three levels of joint spaces; the antebrachiocarpal where most of the joint motion takes place, the middle and the carpometacarpal space.
Joint`s stability is provided by ligaments of the carpus. Carpal ligaments are very stiff and short mostly crossing only one joint level. (image 1), (1)
Luna was afebrile, lame on her right front limb, grade II. Her right front limb was shaking while standing and her carpal joint was slightly flexed. Right carpal joint was obviously swollen on the medial side. Carpal range of motion was mildly decreased in flexion, distinct pain was observed on flexion of the carpal joint and by pressing on the firm medial swelling. No apparent instability could be observed while doing clinical exam but only slight valgus. The rest of physical and neurologic exam was normal.
Orthogonal and stress radiograms of both carpal joints were made and beside increased opacity of medial carpal soft tissue, extensive mineralisation near medial carpal compartment was noticed most apparently on the craniocaudal view. Stress radigraphs showed moderate instability on the medial side of all carpal joint levels. (image 2 to 4)
Decision in making the right therapeutic approach was difficult. After taking under consideration all of the data especially chronicity of the problem, we advised the owners do a pancarpal arthrodesis. Chronic instability is by far the most common indication (in 76% of the cases) for (pan)carpal arthrodesis. (2)
We could also try to do a synthetic ligament reconstruction but since the problem was present for almost a year, the instability was present in multiple medial carpal levels and the dog did not improve, arthordesis seemed like a prudent decision.
Hybride pancarpal arthodesis locking plate (Veterinary instumentation) (2,7 – 3,5) was used for the procedure, taking care to cover 75 % of third metacrapal bone, which resulted in a strong stabile environment and rapid healing with quick return to good postoperative function. External coaptation with a splinted bandage added extra support for the first three weeks after procedure. (Image 5 and 6)
Luna did have some problems with compensation for the first two weeks after the splint was removed, but than started to improve consistently. Follow up xrays at 4 and 8 weeks were unremarkable.
Luna is a very active young German Boxer who was intermittently but progressively lame for the last year. A chance to reconstruct the torn medial ligaments of carpal joint was probably unknowingly lost when the instability was missed at the first veterinary visit almost a year ago.
Chronic instability is seldom succesfully solved by synthetic reconstruction which purpose is to achieve good and functionally strong stability. Unsatisfactory surgical stability again leads to pain and degenerative joint disease.
Dispite apparent instability prooved on xrays, we were not sure how much it contributed to a development of chronic tenosynoviitis but we presume that the proximity of two structures resulted in abductor pollicis longus tendinopathy as well or differentially looking could also be a sign of an old avulsion fracture.
1 Fractures and Other Orthopedic Conditions of the Carpus, Metacarpus, and Phalanges, Part II: fractures and orthopedic conditions of forelimb, in BRINKER, PIERMATTEI, AND FLO’S HANDBOOK OF SMALL ANIMAL ORTHOPEDICS AND FRACTURE REPAIR, Fourth Edition, 2006, by Elsevier Inc., page 382, chapter 14
2 Pancarpal arthordesis in a dog: a review of forty-five cases, Robert B. Parker, DVM, S. Gary Brown, DVM and Alida P. Wind, DVM in American Collegue Of Veterinary Surgery.
In our experience most of the patients with TTA surgery are large breed dogs between 25-45kg. We heve had experienced to work with gient dog (70kg Neapolitan mastiff) and very small dog (6kg Poodle). Furthermore, the expectations before surgery were that the bigger dog will be a problem for setting the implants, but after both surgeries we were surprised how difficult was to set all implants into the smaller dog. Making the plane of TTA surgery for small dog our biggest concern before the surgery of poodle was how we would cut the bone, but that part was easiest of the surgery. Placing the cage and screws was the real challenge. The toughest job was insert the fork into the TTA plate that took most of the time of surgery. Overall, TTA would be the first chouse for ACL rupture in dogs.
Dr. Lucian Fodor (Happy Pet Timisoara, Romania)
Hemilaminectomy is a surgical tehnique of decompresion of the spinal cord wich is made by making a bone space in the lateral part of the vertebral arch.
Hemilaminectomia made a direct decompression of the spinal cord and extraction slight herniated disc. It is indicated after lateral medullary compression, lateral or ventral-dorsal side.
Amstaff female, 9 years old, spayed, at 2 years sufered a car crash who took to the amputation of the left anterior leg.24 hours ago she expresssed paraplegia on the posterior legs, no related to the trauma she had 7 years ago.(Fig 1,2)
Normotermia, heart and respiratory rate are phyziological, biochemical parameter of blood also in normal rates.Neurological tests are showing a flasc paralysis of the posterior legs with keeping of the deep sensitivity and lack of the superficial one.
RMN which shows a protusion of the L6-L7 intervertrebal disc.(Fig 3-8)
Right ventro-lateral disc hernia
Skin incision paramedian
Subconjunctival tissue incision until dorsal lombar fascia
Fascia incision and supraspinos ligament(fig.10) lombar mulfifizi muscle removed from the spinous processes(fig. 11).
Highlighting mamilonat process and the process of lumbar vertebra accessory(fig. 12).
Sectioning mamilonat process using a bone pinching (fig. 13).
Highlighting the nerve root L6-L7 (fig. 14).
Milling articular surfaces L6-L7 (fig. 15).
Highlighting the spinal cord and intervertebral disc herniation(fig. 16-17).
Curettage intervertebral disc and nerve root highlighting decompressed (fig. 18).
Collagen Dressing(fig. 19).
Postoperative treatment was followed five days containing corticosteroids, antibiotics five days and bladder catheterization in the first 24 hours after it is no longer necessary.
Results and discution
Hypotonic paraplegia more than 5 days
flaccid paraplegia with profund sensitivity and no more than 24 hours (1)
cauda equina sindrom (2)
Surgery is superior to conservative treatment (2).
In the case of a herniated disc which is manifested clinically by flaccid paraplegia but keeping deep painful sensitivity, the percentage of success and full recovery of patients is 80% (4).
– Postoperative evolution of the case presented was very good at 24 hours postoperatively she maintained the tripodal position and the movement is made supported by the owner(Fig 20)
– Three months after surgery the animal is completely heald, exhibiting no neurological symptoms
- Robin (Y) – Les traitements de la maladie discale du chien P.M.C.A.C. 2008 (413-424)
- Shores (A) – Intervertebral disc discose. Textbook of small animal ortopedics, ed. Philadelphia, J.B. Lippincot Co 2006 (739-764).
Corresponding author :
Dr. Vladislav Zlatinov,
Central Veterinary Clinic
Chavdar Mutafov str, 25 B, Sofia, Bulgaria
Key words : Total hip replacement, FHNO revision, Biomedtrix universal hip system, BFX, CFX
This a case report of successful revision of femoral head and neck ostectomy (FHNO) with hybrid BioMedtrix (Boonton, NJ) total hip replacement (THR) system, in a 7 years old mix dog. The revision indications in the case were chronic pain and functional impairment after previous excision arthroplasty for severe coxo-femoral arthritis. The weight of the patient (43kg), incomplete resection of the femoral neck and concomitant orthopaedic condition (elbow osteoarthritis) could had been contributing factors for the FHNO bad outcome. A preoperative computer tomographic (CT) study was used for underlaying cause exploration and planning the replacement arthroplasty. The time window between the two surgeries was unusually long- three years. This had caused serious morphological alterations and made the surgery of upmost technical difficulty. Nevertheless, the revision of FHNE to THR produced marked clinical improvement and return to normal activity within 3 months after surgery.
THR is a salvage procedure involving replacement of a diseased pelvic acetabulum and femoral head with implants. Common diseases which necessities this advanced bionic surgery are osteoarthritis, secondary to hip dysplasia or trauma, aseptic femoral head necrosis, acute or chronic hip luxation, failed FHNO, irreparable acetabular or femoral head fracture.
Actually, the canine THR became commercially available since 1974 (Hoefle) and huge advancements in canine and feline THR have been made in the past 30 years. At the present, two cementless commercial systems are most popular, and several other under development1.
The Zurich Cementless Hip Prosthesis (Kyon, Switzerland) provides immediate fixation of the acetabular cup by a press-fit insertion (plus option for screw fixation); Locking screws are used for immediate fixation of the femoral stem, and on growth of bone provides long-term stability.
The BioMedtrix biologic fixation system (BFX) is a modular, press-fit bone ingrowth system with an unsecured acetabular component that provides the advantage of size compatibility with the components of the BioMedtrix cemented THR system (CFX). The advantages of application hybrid THR are discussed further in the case report.
Implants design and procedures in canine THR have been well reviewed in the literature. There are several studies reporting the functional outcomes and complications.2,3 Over- all excellent clinical results and reasonable (2-5%) major complications occurrence are reported by the experienced surgeons in the field.
Never mind the specific implant system used, the THR surgery should achieving the ultimate goal of relieving pain and improve the patient’s quality of life by returning normal limb function. Optimally, the functional effect and the integrity of the prosthesis should last for a lifetime. Serious complications- that could be met in the procedure should be avoided by precise surgery planning and perfect aseptic and surgical technique.
Femoral head and neck ostectomy (FHNO) is alternative low- cost salvage procedure. It intend to eliminate bone-to-bone contact of the diseased acetabulum and femoral head, through the formation of a pseudoarhrosis composed of non-painful fibrous connective tissue.
Published reports about outcome results after FHNO have been controversial. These ones based on gross veterinarian observations or client questionnaires, show encouraging improvement in clinical signs for the majority of dogs.
The more objective gait analysis data (available only recently4,5,6,7) didn’t reveal so optimistic results. Not ideal outcome in function was most evident in studies that did not rely only on owner satisfaction. Common residual dysfunctions after FHNO include: persistent lameness, restricted hip ROM , limb shortening, decreased stifle and hock angulation and muscle atrophy. The maximum functional recovery from the procedure may take up to 8 months6,7,8. Logically, the functional outcome of FHNO is affected by surgical technique, severeness of the disease, age, post op physical therapy and body weight 9. Several clinical trials suggest lack of constant results in dogs heavier than 18 kg.10,11,12 . The cause of the suboptimal outcome in larger dogs is still controversial. Some studies blame the bone-to-bone contact from inadequate excision or postoperative bone proliferation13,14; Others suggest that the bone contact is commonly found after FHNO and do not explain the different clinical outcomes15,16.
In cases of unacceptable pain relief, following FHNO, a revision osteotomy could be contemplated to correct a residual bone-to-bone contact, if present. A more aggressive ostectomy (including trochanter minor) or usage of muscle flaps “slings” modifications could be used to improve the outcome, again with unpredictable outcomes12,17. Another viable option could be conversion to THR18,19,20 . Nevertheless, revisions to THR were reported to yield good and pain-free function (Gofton, 1982; Liska et al. 2010, Fitzpatrick et al. 2012) many obstacles lay in front of successful procedure. The presence of unstructured fibrous tissue and altered anatomy at the surgery site complicates the surgery, and manipulation of a previous surgical site increases the risk of infection. After an excision, the acetabulum fills in with bone and the proximal femur remodels with bone resorption at the excision surface and sclerotic bone production in the medial proximal endoosteal surface. Complications are more likely after revision of FHNO, so dogs that are initially better candidates for a THR, should not be offered excision as an interim procedure.
A 7 years old female mix breed dog (43kg) was presented for consultation because of chronic left hind leg lameness. A femoral head and neck excision was accomplished 3 years ago, but the patient never show adequate pain-free recovery afterwards, despite persistent usage of anti-inflammatory medications.
The patient had a history of previous surgeries (Fig.1-2)- left hip luxation was treated by toggle-pin reduction technique, five years ago. At the same traumatic incident, right intra articular ulnar fracture was diagnosed and osteosynthesis with neutralisation plate was applied. Despite the successful healing, degenerative joint changes developed gradually in the elbow afterwards.
In the previously luxated left hip, progression of severe degenerative changes and clinical deterioration towards severe disabling lameness were demonstrated after the treatment. This why, FHNO was accomplished 18 months after the primary trauma (Fig.3). Radiographic signs of osteoarthritis progression were noticed also in the opposite, right hip joint. The primary cause was hip dysplasia, but no painful clinical consequences were confirmed.
At the clinical exam we found a moderate (II/IV) left hind leg lameness. (video1). At manipulation the hip demonstrated restricted ROM, with obvious pain and crepitation feeling in extension.We found considerable limb muscle atrophy. The opposite hip also had decreased ROM but no pain was elicited through extension.
A CT imaging was used for better evaluation of the FHNO failure (Video 2). Our clinical and imaging interpretation was- residual bone-to-bone contact, caused by suboptimal FHNO and caudal- distal “under-excised” femoral neck.
Dorsal displacement of the femur could have exaggerated the residual contact. Schiatic nerve adhesions were not supposed.
Planning and templating
Preoperatively, magnification-calibrated radiographic study of the femur and pelvis was accomplished. The approximate size of the acetabular cup and femoral stem were determined using acetate template overlaid on radiographs, but with doubts considering the real bone quality of both- the acetabular and femoral components.
Actually, the CT images played a crucial role in the detailed evaluation of the abnormal morphology, present 3 years post FHNO surgery.
Appreciating the femoral component, challenging technical problem was found. A severe proximal femoral canal sclerosis (much more obvious on CT images compared to the pre op X-rays)- Fig.5. This secondary changes always interfere with the well aligned, centralised process of reaming and broaching into the femoral canal. The eccentrically dense bone structure inevitably pushes the canal instruments out of the ideal position, increasing the risk for stem malposition and iatrogenic femoral fracture. This plus the advanced age was appreciated as risk factors for femoral shaft fracture, so a decision for the safer cemented femoral stem (CFX № 7) insertion was made. Because CFX stem have collar, laying against the proximal canal opening, plan was made to correct of the previous FHNO cut, lowering it.
Another technical issues were met, evaluating the pelvic component. A flattened, critically shallow acetabulum was found on the CT images, not clearly visible on the radiographs (hidden by the false hoarse bone proliferation). This made the precise cup sizing challenging. The CT (including 3D reconstruction) images, were used for analysis the real bone stock present in the “pseudo acetabulum” area.
The smallest possible cup (24 mmBFX) was templated but still without adequate dorsal bone engagement.
Fortunately, the Biomedtrix THR system offers an unique clinical solution in these difficult cases. Because of the cylindrically shaped press- fit anchoring mechanism , the Biomedtrix BFX cup may offer great stability properties if just adequate cranial and caudal bone contact is achieved. A rarely applied technique of medial acetabulum wall penetration, allows deeper cup insertion , increasing the stability of the implant-Fig.6.
This stability is provided by the press-fit cranial and caudal cup edges flush. Logically, the technique demands ideal starting point of the acetabular reaming, because any offset may cause inadvertent dorsal bone loss or devastating acetabular fracture-Fig.7. No option for switching towards cemented cup would be present in these circumstances. So a plan for hybrid THR (BFX cup and CFX stem) was made. Excellent clinical results with hybrid Biomedtrix system were reported (Gemmill TJ, Vet surg, 2011).
A standard cranio- lateral approach to the hip joint, including full tenotomy of the deep gluteal muscle, was used. The sciatic nerve was not exposed during the procedure. Advancing through the excessive fibrotic tissue formed at the previous surgical field was extremely challenging and time consuming. It included sharp and blunt tissue dissection. A serious haemorrhage was met from unrecognised arterial vessel in the caudo- distal part of the surgical area. Direct clamping was attempted but not possible, so gauze compression was applied, during the whole procedure.
The replacement arthroplasty was accomplished, following the algorithms and rules provided by the implants manufacturer (more detailed information could be found at http://biomedtrix.com). Only the important technical problems and solutions are described in the following surgery protocol.
A pelvic positioning device was placed underneath the patient, before the aseptic preparation.
A full external femoral rotation to 90 degrees was not possible in the case. The presence of diffuse inelastic fibrotic adhesions, restricted significantly the manipulation of the femur. Two assistants were used to improve the manipulation and retraction at the surgical site. Using a resection guide, aligned with the central axis of the femur, the remnant of the neck was resected according to the preplanned.
A blunt-tipped Hohmann retractor was used to elevate the proximal femur from the wound. Adequate but still more or less suboptimal passage to the canal was achieved.
Femoral canal preparation
The entry point was difficult to visualise because of the solid sclerotic bone, present in the trochanteric fossa. The femoral canal was entered with great care to the alignment, gradually starting with initial 3 mm pin and proceeding with 5 mm drill bit.
The canal was opened and expanded through reaming of caudal and lateral femoral neck’s walls. Extremely hard cortical bone was found in the caudal and medial femoral neck area. It caused considerable resistance to consequent broaching process. It was physically demanding to resist the tendency of the broach to slide back into malalignment during reinsertion. Small crack fracture (about 3 mm bone fragment) was inevitably caused at the medial wall edge.
No margin of cancellous bone was preserved between the implant and the cortex in the case. Temporary gauze compression of the canal was used to restrict the bleeding, during the following procedure of acteabulum bed preparation. After the BFX cup insertion, the stem was fixed to the femoral canal, using gentamycin impregnated cement.(Biomedtrix 3 G veterinary bone cement) applied by improved pressurised technique (using cement restrictor). No stem centraliser was used in the case.
Meyerding retractors were used to reflected fibrotic soft tissues away of the acetabulum. A Hohmann retractor tip was positioned ventro-caudally of the acetabulum, so a femoral shaft retraction was achieved through a lever arm effect. The visibility to the pelvis was quite satisfactory. An emphasis was put on NOT- starting the acetabular reaming in the dorsally migrated pseudo- acetabulum (nevertheless reliable landmarks were difficult to found). First, the reaming was started approximately 20 degrees to perpendicular, and afterwards changed to the desired cup insertion position. Sequentially larger reamers were used. Very careful and gradual medial wall penetration was accomplished, incrementally testing the acteabular depth with a trial cup. The size of the opening was reasonably big and the periosteum could not be preserved. The toggle pin from a previous surgery was retrieved during the procedure.
Post op radiographs evaluation
Excellent implants’ stability and reasonably good orientation were appreciated on the post op X- rays (Fig.9).
BFX cup- a mild negative inclination and moderate retroversion was noticed. There was an excellent incorporation within the acetabular bone.
CFX stem- excellently centered in the frontal plane , but caudally tipped in the saggital plane. There was good cement filling, except small cavity in near the medial femoral wall.
The caudo- distal stem deviation, was probably caused by restricted proximal femur manipulation and suboptimal canal passage availability. It had precluded good alignment broaching and stem insertion- Fig. 10. A potential negative effect of eccentrically placed stems (tip contacting the cortex) could be a creation of stress riser effect and increased risk of femoral fracture, especially if BFX stem is being inserted. The use of cement mold centraliser may had improved the stem orientation, but was unavailable in this case- Fig.11.
Post operative care and follow up
Postoperative analgesia included NSAIDs for 4 weeks. The dog was discharged the next day after surgery, with owner instructions for strict cage rest: controlled leash walking only for 10 minutes, 2-3 times daily.
The patient was toe- touching for 5 days post op with gradual increase of the limb usage; real weight bearing 7 days after the surgery. Physiotherapy was restricted to passive range of motion (home exercise).
A close follow-up was performed by phone contact with the owner. Radiographs were repeated at 12 weeks post op- Fig. 12. They revealed good implants stability; a femoral cortex hypertrophy was noticed around the stem tip area. This was appreciated as physiological remodelling due to altered bone stress bearing.
The patient revealed gradual , but consistent and sustained full clinical improvement. Unrestricted activity was allowed for 12 weeks, when normal (pain free) limb function was appreciated (Video 3). Increased left hind leg muscle mass was found even in this short post op period. Return to normal ROM was found at the recheck (Video 4). Very good perceived quality was reported by the owners.
Transforming of FHNO to THR is a challenging but viable treatment option, even in severely complicated cases. The Biomedtrix system offers great implants’ design advantages, including combination of hybrid elements; excellent BFX cup anchorage, even in deformed shallow acetabulums.
Difficulties and complications could be faced during the FHNO revisions. These met in this case were manageable, but a higher complication ratio could be expected in similar scenarios. The major causes are the profound morphological changes present after femoral head and neck excision, and the fibrotic adhesions restricting the optimal femoral manipulation during the procedure.
The veterinary professionals , should use FHNO technique wisely, taking into consideration its financial/clinical advantage and disadvantages. The excision arthroplasty should never be suggested as a temporary clinical relief in large breed dogs because more or less it disrupts the normal bio- mechanics, causes length discrepancy and have unpredictable pain relief, requiring prolonged rehabilitation or a revision surgery.
During initial discussions about treatment options, the owners should always be treated fare with evidence based approach and realistically expected results explained. This could protect many dogs from suboptimal functional results, following FHNO recommendation in inappropriate candidates.
1. Jeffrey N. Peck, Denis J. Marcellin-Little; Advances in small animal total joint replacement ISBN 978-0-470-95961-9
2. Olmstead ML,Hohn RB,TurnerTM:A five-year study of 221 total hip replacements in the dog. J Am Vet Med Assoc 1983;183:191–194
3. Iwata D, Broun HC, Black AP, et al: Total hip arthroplasty outcomes assessment using functional and radio- graphic scores to compare canine systems. Vet Comp Orthop Traumatol 21:221, 2008.
4. BrezonJL,HowardPE,CovellSJ,etal: A retrospective study of the efficacy of femoral head and neck excisions in 94 dogs and cats. Vet Surg 1980;9:88–92
5. Dueland R, Bartel DL, Antonson E: Force-plate technique for canine gait analysis of total hip and excision arthroplasty. J Am Anim Hosp Assoc 13:547, 1977.
6. MontgomeryRD,MiltonJL,HorneRD,etal:A retrospective comparison of three techniques for femoral head and neck excision in dogs. Vet Surg 1987;16:423–426
7. GendreauC,CawleyAJ:Excision of the femoral head and neck: the long term results of 35 operations. J Am Anim Hosp Assoc 1977;13:605–608
8. Excision arthroplasty of the hip joint in dogs and cats. Clinical, radiographic, and gait analysis findings from the Department of Surgery, Veterinary Faculty of the Ludwig-Maximilians-University of Munich, Germany. 1997.
9. DuffR,CampbellJR: Effects of experimental excision arthroplasty of the hip joint. Res Vet Surg 1978;24: 174–181
10. Ganz R: A new periarticular osteotomy for the treatment of hip dysplasia: technique and preliminary results. Clin Orthop 232:26, 1988.
11. Penwick RC: The variables that influence the success of femoral head and neck excision in dogs. Vet Med 87:325, 1992.
12. Mann FA, Tangner CH, Wagner-Mann C, et al: A comparison of standard femoral head and neck excision and femoral head and neck excision using a biceps femoris muscle flap in the dog. Vet Surg 1987;16:223–230
13. Lippincott CL: Improvement of excision arthroplasty of the femoral head and neck utilizing a biceps femoris muscle sling. J Am Anim Hosp Assoc 17:688, 1981.
14. Tarvin G, Lippincott CL: Excision arthroplasty for treat- ment of canine hip dysplasia using the biceps femoris muscle sling: an evaluation of 92 cases. Semin Vet Med Surg Small Anim 2:158, 1987.
15. Duff R, Campbell JR: Effects of experimental excision arthroplasty of the hip joint. Res Vet Sci 23:174, 1978.
16. Duff R, Campbell JR: Radiographic appearance and clinical progress after excision arthroplasty. J Small Anim Pract 19:439, 1978.
17. Lewis DD, Bellah JR, McGavin MD, et al: Postoperative examination of the biceps femoris muscle sling used in excision of the femoral head and neck in dogs. Vet Surg 17:269, 1988.
18. Noel Fitzpatrick, Duniv, MVB, CertSAO, CertVR, Laura Pratola, BSc: Total Hip Replacement after Failed Femoral Head and Neck Excision in Two Dogs and Two Cats .Vet Surg 41 (2012) 136–14
19. GoftonN,Sumner-SmithG:Total hip prosthesis for revision of unsuccessful excision arthroplasty. Vet Surg 1982;11:134–139
20. LiskaWD,DoyleND,SchwartzZ: Successful revision of a femoral head ostectomy (complicated by postoperative sciatic neurapraxia) to a total hip replacement in a cat. Vet Comp Orthop Traumatol 2010;2:119–123
Dr Ates Barut, DVM, PhD
Owner of Small Animal Veterinary Clinic PETCODE
We can describe Chiari-like Malformation as an overcrowded and narrow caudal occipital fossa and cervicomedullar junction due to a congenital developmental malformation of caudal occipital bone. Disease is similar to Chiari Type I disease in humans and therefore named as «chiari like malformation» in dogs.
Chiari-like malformation is a hereditary condition and first described in king charles cavalier spaniels and altough several other small breeds can become effected king charles cavaliers are the most common breed effected by the disease.
The other reported breeds are; Griffon, Miniature poodle, Yorkshire terrier, Maltese, Chihuahua, Bichon frise, Staffordshire terrier, Pug, Shih Tzu, Dachsund, Pincher, French bulldog, Jack Russel Terrier, Pekingese and Boston terriers.
Affected patients has a kind of cerebellar compression and narrowing around foramen magnum and cervicomeduller junction.
Bony compression, progresive meningeal hypertrophy and dural fibrosis cause; several different neurological dysfunction like cerebellovestibuler disfunction, cervical myelopathy, seizure activity, syringomyelia, ventricle dilatation and hydrocephalus
Although in humans almost all chiari malformation patients has some degree of cerebellar herniation , in dogs cerebellar herniation is not that common and this is the main difference between these 2 species. Caudal occipital malformation syndrome is a genetic deformation of the mesoderm of caudal occipital bone causing cerebellar compression and herniation.
In normal dogs CSF move from cerebral subarachnoid space to cervical spinal subarachnoid space through foramen magnum in every sistom and diastol in a pulsative manner.
Compression and partial obstruction caused by Chiari malformation disturb CSF flow in both ways but because of high systolic pressure push CSF to central canal of cervical spinal cord and produce a cavity with this hammer effect. Valsa maneuras like barking and coughing, make sudden changes in intrathorasic and intraabdominal pressure which cause epidural venous distention and fast fluid acumulation to the cavity. Because of spinal epidural vein distention and compression in cervicomedullar junction syringomyelia cavity continue to enlarge gradually.
Herniated cerebellum increase the amount of obstruction , CSF flow and fluid accumulation. CSF will flow from intrcranial cavities to cervical region easier but can not come back again.
Symptoms and clinical presentation
We can list the possible symptoms as; cervical hyperaesthesia, scratching( air scratchig or phantom scratching)
, facial rubbing, air licking, fly catching, tail chasing, vocalization, pain reaction during atlantoxipital palpation., cervical myelopathy, fore leg paresis characterized by lower motor neurons, multifocal CNS dysfunction, torticollis, scoliosis, seizure activity.
Pain due to or seconder to syringomyelia is a very important symptom and it happens because of the damage on the dorsal horn of spinal cord.
It usually happens Because of the hypersensitivity due to the damage on spinothalamic pathways and/or dorsal horn neurons
Abnormal sensitivity in head, shoulder, neck, axillar and sternal regions is prominent in several patients with syringomyelia but pain severity is not directly correlated with the amount of the fluid inside the spinal cord. Pain is most common in king charles cavaliers and usually more dominant in one side.
Scratching is another very common sign in king charles cavaliers and stress, excitement or a touch to the neck stimulate or increase sctraching. Some dogs has a scratch point and react to a simple touch to this point. The scratching style usually without touching the body is also unique and that is why named as air scratching or phantom scratching.
In some severe cases the patients can have cervical myelopathy, cerebellovestibüler dysfunction and multifocal central nervous system dysfunction. In these cases severe neck pain, strabismus, head tremor and nystagmus can be observed. Loss of muscle tone due to asimetric innervation of paraspinal muscles can cause opusthotonus.
Some patients with chiari-like malformation can have seizures but pathogenesis is not so clear. This rare condition can be related with impaired cerebellar functions because cerebellum has an inhibitoric effect on seizure activity.
Magnetic resonans imaging is the only way for exact and definitive diagnosis of chiari-like malformation and syringomyelia. T2 and T1 weightened midsagital and transversal images of
the foramen magnum, caudal occipital fossa and cervical spinal cord will show syringomyelia.
We can describe magnetic resonans imaging findings as a narrow subarachnoid space in cervicomedullar junction, occipital bone compression on caudal cerebellum, rostral movement of caudal cerebellum, syringomyelia, cerebellar herniation from foramen magnum and kinked appearance of caudal medulla.
Lateral vetricle dilatation is a very common sign but hydrocephalus is a possible but rare condition.
Most of the patients with syringomyelia can spend their whole lives with mild neurological symptoms without any need for medical or surgical treatment. Life quality is the main concern for treatment decision. Patients with obvious neurological signs and pain and non-responsive to pain managment therapies are candidates for surgery. Patients with mild symptoms and pain or non-responsive to pain medication are candidates for medical treatment.
Non-steroidal antinflamatoric medications are not effective against neurologic pain. In severe cases pain can be manage just by some anticonvulsants like gabapentin( 10mg/kg tid) or pregabalin (2-4 mg/kg bid). Last researches showed that omeprazol decrease cerebrospinal fluid production and can be used in some patients but some studies done in rats showed that long term use can cause hypergastrinemia and increase the risk of stomach cancer.
The other medicatios can be used to depress the clinical signs of syringomyelia are; acetozalamide, furosemide, corticosteroids, and phenobarbital. Another promising medication for neurologic pain is palmitoylethanolamide (pea) nad can be effective in several syringomyelia patients.
Surgical treatment is indicated in patients with worsening neurological signs and unresponsive pain. Aim of the surgery is to reorganize cerebrospinal fluid flow pathways and decrease the abnormal CSF in side the central nervous system by decompressing cerebellum. For this aim “Foramen magnum decompression” is indicated by a suboccipital craniectomy and partial dorsal laminectomy of first cervical vertebra that enlarge foramen magnum .
Foramen magnum decompression window limits and borders are so important. A small window will be effectless and a large window can cause atlanto-occipital instability or excessive bleeding in a very sensitive area which can cause life treating situations. Lateral borders of the window are atlantooccipital joints and lateral vertebral foramens of atlas , rostral borders are midpoint of the distance between protuberentia occipitalis and dorsal border of foramen magnum, caudal border is ¾ of atlas. Durotomy and marsupilization of dura to the muscular structures around the foramen magnum window is the common procedure but cerebrospinal fluid leakage can cause an inflamation and this inflamation can lead severe soft tissue thickening which can cause compression in the area. Altough durameter is firmly attached to the bony structures in atlantoaccipital region carefull dissection can be done without duratomy to prevent csf leakage.
Foramen magnum decompression will reorganize cerebrospinal fluid flow but the present fluid and the syringomyelia cavity will remain which means the present symptoms will continue most of the time. Foramen magnum decompression is most effective against pain which is the most common indication of surgical treatment.
To drain the present syrinx in syringomyelia cavity “syringosubarachnoid shunt application” is the most effective and popular method. Approach to spinal cord with a dorsal laminectomy where the syrinx cavity is most prominent has to be done first. After a “T” shaped duratomy placement of a shunt in 1-1.2mm thickness from syrinx cavity to subarachnoid space has to be performed to complete the procedure.
As a result chiari-like malformation and syringomyelia is one of the most important breed predispositions of veterinary medicine and although the disease is reported in several other breeds it creates a very important clinical problem among king charles cavalier population. Most of the patients with syringomyelia can live whole their lives with very mild symptoms within a normal life expectancies but some patients will have cervical myelopathy, cerebellovestibüler dysfunction and multifocal central nervous system dysfunction. Pain and life quality is the main concern and criteria for treatment. Patients with obvious neurological signs and pain and non-responsive to pain managment therapies are candidates for surgery. Foramen magnum decompression and syringo-subarachnoid shunt application are the two surgical procedures described to reorganize normal cerebrospinal fluid flow and drain syrinx from its cavity.