Treatment of massive brain compression in two dogs

1575875879547blobDr. Vladislav Zlatinov

Central Vet Clinic

Sofia, Bulgaria

 

Introduction

 

This is case series of two dogs with similar advanced brain compression. The aetiology was different, but in both cases there was gradual epidural compression, indeed allowing survival of the patients. The final size of the brain compression lesions in both dogs was impressive and was related to the delayed diagnostic process. Both dogs were successfully treated and followed in next few months post op. Different surgical approaches and techniques were applied, according to the specific needs.

These cases present interest because such large lesions are rarely met in practice, and may be considered untreatable by some veterinary clinicians.

 

 

Case 1

 

Referring Vet: Dr. Evgeni Evtimov

Corresponding authors Dr. Aglika Jordanova (Clinical pathology), Dr. Vladislav Zlatinov (Surgery),Dr Nikola Penchev( Anesthesia)

 

 

Felix, a 7 months old Collie dog was presented for treatment of progressively deteriorating central nervous system dysfunction.

 

The male puppy lives in an apartment; vaccinations and deworming are current, fed on regular dry food diet. Had been with his owner for a month, came from a breeder.

 

The clinical signs had started 3 weeks ago, with unclear manifestation- decreased appetite, lethargy, intermittent fever, unstable walk. The overall body condition of the patient had been appreciated as underdeveloped, and the owner reported the dog is not growing.

Felix had been initially consulted by the referring vet, who had started primary diagnostic and treatment steps. Biochemistry profile, CBC and vector diseases fast serology tests had been done- being normal/ negative, not revealing the specific cause of the condition. Symptomatic antibiotic treatment had been started, without significant improvement. NSAIDs resulted in temporary alleviation of the symptoms – body temperature back to normal, the dog was brighter.

At this point the dog was referred to us to investigate the possible cause of the condition, suspected to be endocrinological.

The dog was found to be lethargic, walking with head positioned low, no pain during head lifting, does not resist opening the jaws, wobbly gait, with normal proprioception of all 4 limbs. body temp.39.0C. The CBC was WNL. Total T4 was normal (16nmol/l). Radiography of limbs and vertebrae showed normal physeal growth for the dog’s age; thus excluding congenital hypothyroidism.

 

Cerebrospinal fluid collection and computer tomography study of the head were suggested, as the symptoms were assessed as central neurological. During the period of owner contemplation, trial course with corticosteroids had been applied. Short-term clinical improvement had been noticed, followed by further decline in the dog’s condition. A bulge on the left side of the head became visible.  After gradual progression of neurological symptoms- dull behaviour, mild head tilt, inactivity, the dog deteriorated profoundly to the status of stupor- severely depressed mental status, barely reacting to stimuli.

 

CT study of the head was performed 14 days after the initial examination at Central Veterinary Clinic (with no anaesthesia needed), revealing dramatic findings. Extensively grown soft tissue “mass” (vs thick fluid accumulation) was found over and under (extra and intracranially) the left parietal and occipital skull calvaria. The outside lesion was more heterogeneous, lobular like, under the temporal fascia. The internal part was homogenous, with clear fluid density, well encapsulated, caudally extending over cerebellar tentorium. It was causing a significant mass effect with compression of the left parietal and occipital cerebellar brain lobes. Dramatic lateral ventricular compression and a falx shift to the right was present.The skull bone in the area was hypertrophied, with aggressive periosteal reaction, mostly extra- cranially. In the cranial left parietal bone, a small concave defect was noticed on 3d reconstruction images.

Fine needle aspiration was done puncturing the extra cranial lesion area. Pus-like  fluid was obtained, cytologically tested, confirming suppurative process.

 

All these findings suggested the main differential diagnosis- massive epidural empyema (abscess), compressing the brain parenchyma and causing profound neurological deficit. The probable cause was bite wound on the head (<=concave defect on the parietal bone).

 

Surgical decompression was suggested and accomplished as an urgent procedure because of the fast deterioration of the patient.

 

Lateral approach to the skull was applied. An abscess cavity with intensively neo-vascularised capsule was found, just under the temporal fascia, Topographically it was within the temporal muscle tissue. After partial capsule resection and copious lavage, the soft tissues were undermined and reflected to expose the lateral (parietal) skull area. Next, rectangular  rostrotentorial craniectomy was accomplished using maxilo-facial mini oscillating saw. Skull sutures and the concave defect (bite area?) were used as reference landmarks to orientate the cuts. The skull bone in the area had reached 1 cm thickness. A fluid filled epidural (over dura mater) cavity was found. It was filled by thick bright yellow purulent fluid. After microbiology and pathohistology sampling, the pus was aspirated and the residual cavity copiously lavaged. Prompt haemostasis was applied, with minimum haemostatic materials left in place.

A fenestrated drain tube was inserted into the empyema  cavity and under the soft tissues. The temporal fascia and the skin were closed routinely over the defect. The drain tube was connected to active vacuum suction system.

Intense post op care was applied in the next 12 hours- blood pressure monitoring and correction with vasopressors, fluid infusion, pain control, i.v. antibiotic therapy. The patient started to improve slowly but steadily- the mental status improved within 24 hours, and the dog was able to stand up on the second day after the surgery. On the fourth day it was stable enough to be discharged from the clinic (still with the active vacuum drainage). The last was removed on the 7th day.  Ultrasound examination rechecks was done on the 10th and 14th days, excluding new fluid accumulation.

 

The microbiology culture test result was negative, but no anaerobic isolation media was available. Just in case of not detected anaerobic infection- 3 weeks course with Clindamycin was prescribed.

The pathology report confirmed the the diagnosis of pyo-granulomatous inflammation with no neoplastic tissue present.

 

Eventually, Felix did full recovery with no infection relapses within the follow up period of 4 months.

 

Case 2

 

Referring Vet: Dr. Milena Pancheva

 

Dr. Vladislav Zlatinov (Surgery), Dr. Antoan Georgiev (Anaesthesia).

 

 

 

Beki, 4 years old female Dalmatian was referred for consultation, regarding the possible treatment  of a huge intra-cranial mass.

The dog had a long history of slowly progressing vestibular signs and eventually obvious ataxic walking  Unfortunately the owners had ignored the problem for several months (> 7 m), because of the mild clinical presentation in the beginning and the good overall condition of the patient. Recently the dog deteriorated- difficult to keep balance during walking and eating. Two seizures  and nocturnal hyper excitement activities were also demonstrated.The dog had already computer tomography study of the head, revealing huge cranial mass. An opinion about euthanasia was already suggested to the owners. Empirical therapy with steroids and antibiotics was already applied before the achievement of the correct diagnosis.

 

During our neurological examination we found: normal mental status and vision, normal cranial and limb segmental reflexes; the menace response reflexes were decreased; body posture revealed broad-based stance. The patient demonstrated obvious ataxia. It was defined as cerebellar one, presented by hypermetria and  swaying, mild intentional head tremors.

We analysed the CT study and found: large hyper-dense oval mass, starting from the region of the occipital bone and engaging the cerebellar tentorium. The mass was protruding extensively into the brain cavity, eccentrically to the right side. Bone lysis and infiltration was evident in the right occipital nuchal area and also cranial to the right nuchal crest. Severe cerebellar compression in cranio-ventral direction was evident. Less severe compression of the occipital cerebral lobes (without lateral vetntricular displacement) was also found.

Despite the large size of the mass, we suggested moderate malignancy of the lesion- smooth, encapsulated margins, homogenous density. Bone neoplasia (osteosarcoma and multilobular osteochondrosarcoma) or meningioma were the most probable diagnosis. Slow progression of mass, made the osteosarcoma less probable. The bone involvement is not typical for meningiomas. Multilobular tumors usually has similar imaging features as presented in the case. Their excision offer good opportunity for long-term tumor control, so a surgical decompression and mass removal was suggested and accomplished in Beki’s case.

 

We approached the skull caudo- laterally, undermining and retracting the overlaying temporal fascia and neck muscles. The tumor mass was found protruding from the bone through osteolysed right occipital and parietal bones.  Using speed burr we created large combined occipital and caudal-lateral craniotomy. Excessive bleeding from the right transverse sinus was anticipated but fortunately not found, because of possible gradual vein obliteration. Despite this, during gradual enlargement of the craniotomy, special precautions was taken not damage the ipsilateral left one.

After exposure the cranium, we attempted to determine the mass borders. The tumor was originating from the cranium bone not invading (just compressing) the nervous tissue. Because of the huge size, en block resection was far from possible, so slow “debulking” mass removal was started.  The brain meninga (dura mater) was not affected by the neoplasia, so tissue direction was amenable.

 

Diffuse, moderate but constant bleeding was met through the whole process of removal small partial tumour masses. Haemostatisis was achieved using Cellulose blood clot inducing products (Surgicel mesh) and intermittent gentle compression. Copious lavage was applied during the whole surgery.

 

To complete the mass removal was a laborious procedure, taking itself about an hour. Finally, immediately  after the decompression a visible brain tissue re-expansion was noticed. After prompt haemostatis (using bone wax and Surgicel materials), the residual craniotomy defect was covered with apposition of the soft tissues over it.

 

In the next 24 h post op period, the dog was was given opioid analgesia, anti-inflammatory doses of steroids and anti oedematous osmotic agent (Manitol).

Indeed, Beki started to recover surprisingly fast- eating on the 12 h post op (on the video). For about 48 h she showed exaggerated ataxia, with difficulties in walking, but the coordination started to improve fast. The patient was discharged from the clinic on the third day pos op, walking reasonably well. Harness supported leash walks were recommended.

No physiotherapy was applied in the recovery time, because the patient coordination improved to normal on the 10th days pos surgery.

 

Patohystology evaluation of the tumor was done. The results was Multi lobular bone tumor. This is a low malignant, well differentiated neoplasia. In short term it can be controlled successfully by surgical resection. Slow reoccurrence could be expected, also long term metaplasia to more aggressive osteosarcoma.

 

Recheck of the patient revealed condition undistinguishable from normal. The follow up period till now is 3 months.

 

 

 

 

Transplantation of ipsilateral canine ulna as a vascularized bone graft for treatment of distal radial osteosarcoma

12959354_10153530931267960_1853416198_o-200x300

Dr. Vladislav Zlatinov,

Corresponding author :

Dr. Vladislav Zlatinov,

Central Veterinary Clinic

Chavdar Mutafov str, 25 B, Sofia, Bulgaria

E-mail: zlatinov_vet@yahoo.com

 

 

Abstract

 

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.

 

Introduction

 

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

Fig.1

Fig.1 Osteosracoma treatment algorithm

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.

Fig.2

Fig.2 Allograft limbs spring surgery

 

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.

 

Fig.3

Fig.3 Endoprosthesis limb salvage procedure

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.

 

Fig.4

Fig.4 Ulnar roll-over salvage technique

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

 

Fig.5

Fig.5 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.

Fig.6

Fig.6 Transverse Ulnar Bone Transport Osteogenesis

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.

 

 

 

Case report

 

 

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.

 

Fig.7

Fig.7 Orthogonal limb radiograph

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.

Fig.8

Fig.8 Thoracic X ray

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.

 

Fig.9

Fig.9 Pathological fracture of the cranio-distal cortex

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.

 

 

Fig.10

Fig.10 Segmental epidural analgesia

Fig.11

Fig.11 Sternal recumbency

 

 

 

 

 

 

 

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

 

Fig.12

Fig.12

Fig.13

Fig.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.

Fig.14

Fig.14 Microscope- assisted arterial anastomosis

Fig.15

Fig.15

 

 

 

 

 

 

 

 

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.

Fig.16

Fig.16

Fig.17

Fig.17

 

 

 

 

 

 

 

 

 

 

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.).

 

Fig.18

Fig.18

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.

 

Chemotherapy protocol

 

Fig.19

Fig.19

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.

 

Fig.20

Fig.20 Carboplatin

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.

 

 

 

Fig.21

Fig.21 Three weeks post op

Fig.22

Fig.22 Six months post op

Fig.23

Fig.23 After lateral plate removal

 

 

 

 

 

 

 

 

 

 

 

 

 

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.

 

 

 

 

 

CONCLUSIONS

 

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.IMG_6122