Total hip replacement after unsuccessful femoral head and neck resection in large mix breed dog

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Dr. Vladislav Zlatinov

Corresponding author :

Dr. Vladislav Zlatinov,
Central Veterinary Clinic
Chavdar Mutafov str, 25 B, Sofia, Bulgaria
E-mail: zlatinov_vet@yahoo.com

Key words : Total hip replacement, FHNO revision, Biomedtrix universal hip system, BFX, CFX

 

Abstract

 

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.

Introduction

 

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.

 

Case report

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.

 

Disease history

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.rtindex1

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.ij

 

Clinical examination

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.

A revision with hip replacement arthroplasty was planned.ik

 

 

 

 

 

 

 

 

 

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.pm

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. vg

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).Untitled-7

 

Surgical protocol

Surgical approach
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.

Neck resection
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
Initial opening
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.
Canal preparation
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.

Acetabular preparation
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.

Аfter the BFX cup hammering, there was a feeling for solid, and good flushed cup component- Fig.8.index44

 

Post op radiographs evaluation

Excellent implants’ stability and reasonably good orientation were appreciated on the post op X- rays (Fig.9).index55
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.
Comments
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.index8

The small air defect in the cement was probably caused by leakage through the medial wall fragmentation caused intraoperatively.index9

 

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.index10

 

Results

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.

 

 

CONCLUSIONS

 

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.

REFERENCES
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

CHIARI-LIKE MALFORMATION AND SYRINGOMYELIA

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Dr Ates Barut, DVM, PhD

Dr Ates Barut, DVM, PhD

Owner of Small Animal Veterinary Clinic PETCODE

 

Introduction

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.

Patho-physiology

Bony compression, progresive meningeal hypertrophy and dural fibrosis cause; several different neurological dysfunction like cerebellovestibuler disfunction, cervical myelopathy, seizure activity, syringomyelia, ventricle dilatation and hydrocephalusPicture1Picture2Picture4

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.Picture5Picture6Picture7Picture9
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

Presentetion of the disease is different from patient to the other. The first signs can be seen from 5-6 months to 9-10 years.Picture17Picture18Picture19
The disease can cause several different neurological signs.

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 neuronsPicture20Picture23Picture24Picture27
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.

The most common neurological and physical examination finding is atlanto-occipital pain and increased sensitivity on pin point palpation on atlanto-occipital joint.Picture28Picture29

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.

Treatment

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.

Discussion

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.

Double plated TPLO in oversized dogs

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Dr. Tsvetan Ivanov

Dr. Tsvetan Ivanov, “Dobro hrumvane!” veterinary clinics, Sofia, Bulgaria

Introduction

The most common cause of rear limb lameness in the dog is rupture of the cranial (anterior) cruciate ligament. This derangement results in degenerative changes (osteoarthritis) in the stifle (knee) joint, including cartilage damage, osteophyte (bone spur) production, and meniscal injury. The Tibial Plateau Leveling Osteotomy (TPLO) has proven effective in returning these deranged stifles to full function.

Developed by Dr. Barclay Slocum, TPLO was a radical procedure for addressing canine ACL injuries. Now in existence for over 20 years, the surgery has proven itself, time and time again, to be an extremely effective long term solution for addressing cruciate ligament injury in dogs.

Part of the positive indications for TPLO are:

  • Bodyweight:

TPLO is most frequently performed in medium to giant breeds. Greater bodyweight is a positive indicator for selection of TPLO as a treatment option. The procedure can be performed and on small dogs and even cats, but then should be make exact discretion the potential benefits and complications.

  • Age:

Cruciate ligament degeneration is seen increasingly in young large breeds, in some cases within their first year.

Minimising osteoarthritis in the long term is a priority for these young dogs. Many surgeons believe that this leads to the TPLO being the technique of choice, although long term comparative studies continue to investigate this. These cases frequently show bilateral degeneration, and partial cruciate ruptures are common.

The procedure is good option for dogs over 6 months of age, with progression of ossification of proximal tibial growth plates.

  • Partial ligament rupture.

Cases of partial ligament rupture show a very rapid iprovement following TPLO. Importantly, they typically do not progress to complete ligament failure as TPLO acts to neutralise the forces on the cranial cruciate ligament.

TPLO is widely accepted to give the best functional outcome, in the short to medium term, and has enabled working/performance animals to return to high functional standards.

  • Excessively sloping tibial plateau:

Average plateau angles range from 22°-26°, but angles from 15° are still remain a TPLO candidate with good post-operative outcome. However, in cases with an increased tibial plateau angle, TPLO has proved particularly beneficial.

Case studies have advocated TPLO as the technique of choice for even small breeds with excessive tibial plateau slopes. In some of those cases the amount of angular correction required leads to a Wedge resection technique being favoured over the Slocum(curved-cut) TPLO.

  • Cranially translocated tibial crest.

Occasionally the stifle will rest with the tibia cranially translocated following cruciate rupture the tibial crest is  palpated cranially, the patella tendon is less distinct, and the first movement during cranial drawer is backwards, often associated with a dramatic degree of movement. In some authors experience these cases may return to cranial translocation with significant recurrence of lameness weeks after extracapsular lateral fabella suture placement. In those cases, in a limited number of procedures, TPLO have shown better outcomes.

Overall, the good TPLO candidate is medium to large breed dog, from 6 months and plus, active, with need of full functional restoration of the limb.

The Case:

 

This is the case of Hades. He is oversized cane corso, 6 years old, bodyweight is 78 kg and he suffers from hip arthrosis of the right hip in result of hip dysplasia and chondroma of right carpal bones. He came with lameness on the right rear limb from few weeks, which is worsening. He had and positive “sit and drawer tests.

This is video of his walk:

The diagnosis was cranial cruciate ligament rupture.65 6My favorite procedure is TPLO, but definitely no one can be sure that, the standard procedure can give good outcome with this size dog. Furthermore, the dog have and two other problems on the right side. We were afraid from implant failure so we decided to make insurance. Instead only the TPLO plate we placed and second DCP 3.5 mm plate. The original idea was to use 3.5 screws for the 2-nd plate, but because of the risk from caudal cortex fracture the most distal three screws was 2.7 mm

 

 

 

0 post op DP

Immediately postoperator

0 post op LL

Immediately postoperator

Those are intraoperative pictures and the immediately post-op pictures:

2

surgery

4

surgery

1

surgery

 

Video 14 day after the surgery:

 

X-ray pictures 45 days after the surgery:

45 dni post op - LL

45 days post op – LL

45 dni post op

45 days post operator

And this is the final result – 6 months after the surgery:

240 days post op

240 days post op

Video:

Discussion:

 

The TPLO remains one of the best surgically ways to manage CrCrLR even in oversized dogs, even with concomitant diseases of the locomotor system.

The most important thing is every surgeon to make optimal assessment of the patient’s status and to remember that every case is specific.

TTA surgery for Cranial Cruciate ligament rupture

Vet Tommy

VETERINARY CLINIC TOMMY Belgrade, Serbia

VETERINARY  CLINIC  TOMMY

Belgrade, Serbia

Surgery specialist DVM Goran Tomišić

 

 

TTA surgery for Cranial Cruciate ligament rupture

 

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TTA surgery for Cranial Cruciate ligament rupture

Medical history

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TTA surgery for Cranial Cruciate ligament rupture

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TTA surgery for Cranial Cruciate ligament rupture

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TTA surgery for Cranial Cruciate ligament rupture

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TTA surgery for Cranial Cruciate ligament rupture

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TTA surgery for Cranial Cruciate ligament rupture

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TTA surgery for Cranial Cruciate ligament rupture

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TTA surgery for Cranial Cruciate ligament rupture

Dog , Golden Retriever 4 year old,  29 kg weight, was presented to the clinic with chronic pain and lameness in his left hind limb. Beside that the dog was perfectly healthy.  During the orthopedic examination in sedation, there are persistent sign of drawers  which is the most important sing of Cranial Cruciate  Rupture. On  X- ray  was no osteoarthritis founded. During the preparation for the surgery, measures of the knee were taken from the same  X-ray. Measuring for this procedure must be precise and it’s done with help of special equipment.

 

 

Surgical treatment

 

During the surgery dog was placed in left lateral position, and approach on the knee was from medial side. After exposing the tibial  bone markers were placed  into the tibial crista. Afterwards,  precise cut was performed with special saw to cut of the tibial crista, on that  site the titanium plate was placed with fork. Next step during the surgery is placing a cage into the space between tibial crista and other part of tibial bone  screwing  it with screws. When everything was stabile it was irrigated and closed.

 

Postoperative treatment

User comments

TTA surgery for Cranial Cruciate ligament rupture

 

The dog that we operated was necessary to be under restriction  as much as possible minimum two weeks. After only 24h dog was touching ground with operated leg, but he was on restricted walks for two weeks because of his temperament. There was no postoperative complications, one month later  dog was using his leg practically normal, but he was still under the supervision  of the owner.

 

Pseudomeningocoele in dog

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Dr Zoran Loncar

Z.Loncar, DVM1

1Department of Orthopedic Surgery and Neurology, Veterinary Clinic Novak, Belgrade, Serbia

           INTRODUCTION

A 3,5 years old mixed breed dog was presented at the clinic with finding of non ambulatory paraplegia. Dog was hited by a car 25 days prior to the presentation. Since then the dog has been treated conservatively without any improvement. Radiography study showed L7 fracture. MRI study showed T13-L1 compressive myelopathy caused by disc material, and lesion L2-3 and L3-L4 consisted with the findings of pseudomeningocoele in humans. The purpose of the article is to suggest that a lesion consisted with pseudomeningocoele in humans can be find in dogs in late MRI screening after nerve root trauma.

CASE HISTORY

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Figure 1: Dorsal projection at T2 sequence shows multiple high intensity signal at the level of lumbal nerve roots L2-3, L3-4 to the right. Signal is homogenous, extradural consisted with pseudomeningocoele and CSF leakage

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Figure 2. Sagital image of lumbal spinal cord segment in T2 sequence. Shows high signal intensity at the level of nerve root. Loss of signal intensity at the disc ventral to the lesion L3-4. L1-2 complete of signal intensity. Th13-L1 compressive myelopathy caused by disc extrusion.

A 18 kg BW, 3,5 years old mixed breed dog, without significant medical history was presented at the clinic with owners complain not to be able to walk on hind limbs. The owner had not noticed voluntary movements on hind limbs of dog since had been hited by a car 25 days prior to the presentation at the clinic. There was no other abnormalities on general exam except urinary bladder enlargement and overflow pattern of voiding. Neurology exam showed normal mental status. Non ambulatory paraplegia. Cranial nerves were in normal physiological limits. Segmental reflexes in front limbs were normal. Patellar reflex on left side was increased, on right side was decreased. Withdraw reflexes were decreased bilaterally. Perineal reflex was normal. Panniculus  cut was at the level of L4 bilaterally. Deep pain was present. Hind limbs were spastic with mild muscle atrophy. The dog showed no pain during palpation of L7 fracture site and there was no crepitation  during manipulation of the region. The dog reacted painfully during deep palpation at the level of first lumbal vertebras. The lesion was localized T3 to caudal because of mixture of UMN and LMN signs, slightly lateralized to right.  Radiographs showed L7 fracture with complete dislocation of compartments. MRI findings showed :Fig 1 and 2

The dog was treated surgically right T13-L1 hemilaminectomy with disc fenestration. The owner refused to allow surgically treatment of L7 fracture. Postoperatively the dog was treated with antibiotics ( synulox 250mg BID 10 days), NSAID ( carprofen 25mg BID), and physical therapy. Dog was ambulatory 3 weeks after surgery. 1,5 month after the surgery there was no abnormalities at the neurological exam.

 

DISCUSSION

The case was analyzed for a probable etiology of L2-L3 and L3-L4 lesions visible at the MRI study considering case history, progression of signs, concurrent lesions, lesion distribution and pattern of appearance. It was also taken in count fast improvement of neurological condition immediate after decompression surgery at the level T13-L1. Most of the neurological findings were consisted with all three lesions find during MRI imaging. The lesions at the level of L2-3 and L3-4 were localized at the foramen, extradural, unilateral. Lesion were homogenous, there was no edema surrounding the lesions. Lesion showed T2 hyperintensity, T1 hypointensity. Vascular lesions at that time after the injury would show high intensity signal in both T1 and T2 sequences. Inflammatory or edema would show T2 hyper intensity and T1 hyper or iso intensity of the signal. Anomalous lesion would not be consistent with lesion pattern and neurological deficits connected to the localization without previous clinical signs. Neoplastic conditions would not fit with lesion distribution and progression of clinical signs, but would fit with signal intensity pattern. Taking all data in count lesion fits with the condition well described in human medicine as pseudomeningocoele caused by traction trauma to the nerve roots of lumbal intumescence. This hypothesis is limited by facts that MRI study is not complete. There is absence of FLAIR study wich would support theory that the T2 high signal is due to CSF accumulation. Contrast study would help to eliminate other possible lesions. One could ask question why just two nerve roots were traumatized. And the final limitation is that there is no follow up MRI study done after resolution of clinical signs. Pseudomeningocoele is condition of CSF accumulation due to dura tearing. Major causes are congenital, blunt trauma and traction trauma (1). The mechanism of traction trauma is not clear. It is suggested that can be caused by CSF pressure wave due to increased abdominal pressure (2), or flexion/abduction aggressive movement (3), or flexion/distraction movement (4). There is no correlation between severity of nerve root injury and pseudomeningocoele appearance (4). There is no definitive strategy for pseudomeningocoele treatment (4). Often nerve root injury is more distally than pseudomeningocoele site.

Traumatic cranial cruciate ligament rupture combined with either medial or lateral collateral ligament rupture in two dogs. Surgical stabilisation of the stifle joint using tibial tuberosity advancement and collateral ligament prosthesis

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Dr Svetoslav Hristov

Dr Svetoslav Hristov

United  Veterinary Clinic in Varna, Bulgaria

Multiple ligament knee injury is rare in dogs but more common in cats. Cranial cruciate ligament rupture in dogs is considered to be mainly degenerative in origin rather than primary traumatic which is opposite compared to humans. In the followed two cases there were no signs of preexisting degenerative changes in the stifle joint and they were considered as primary traumatic. In dogs statistically injury to the medial collateral ligament is more common than an injury to the lateral one. Only third degree and some second degree collateral ligament injury leads to stifle joint instability and requires surgery.

Anatomical notes

The main ligamentous support in the stifle joint is provided by four femorotibial ligaments – two cruciate ligaments and two collateral ligaments.

Cranial-Cruciate-Ligament

fig 1

unnamed (3)

fig 2

The lateral collateral ligament in the stifle joint has an insertion points on the lateral.
The cranial cruciate ligament mainly prevents from cranial tibial translation with respect to the femur , hyperextension and excessive internal rotation in the stifle joint
epicondyle of the femur and the proximal part of the fibula with some fibbers also attaching on the lateral tibial condyle (fig.1) . The medial collateral ligament has proximal insertion point on the medial epicondyle of the femur and broad distal insertion point on the caudomedial aspect of the proximal tibia (fig.2) . Some part of the ligament also blends with the joint capsule and has an attachment to the periphery of the medial meniscus. To summarise, the lateral collateral ligament is more loosed, superficially positioned and is taut only in the knee in extension. With the stifle joint in flexion the lateral collateral ligament relaxes which allows axial internal rotation inside the joint which is known as “screw home mechanism”. With the knee in extension, both collateral ligaments are taut preventing from excessive internal or external rotation.

The cranial cruciate ligament mainly prevents from cranial tibial translation with respect to the femur , hyperextension and excessive internal rotation in the stifle joint.

 

18 months male Drahthaar, weighting 32 kg with unknown trauma during hunting. Dog was presented a few hours after the trauma fully non weight bearing with the left hind limb. During physical examination an obvious cranial to caudal instability (positive drawer test) and lateral collateral instability (positive varus test) were detected. Medial to lateral and posterior to anterior radiographs were taken. There were no signs of preexisting degenerative joint disease. The dog was scheduled next day for a surgical stabilisation of the lateral collateral ligament, exploratory arthrotomy and tibial tuberosity advancement for the failed cranial cruciate ligament. After lateral parapatellar approach, the cranial cruciate ligament rupture was confirmed and the remnants were removed. No other intraarticular structures were visibly injured. By retracting the biceps muscle caudally, a mid substance tear of  the lateral collateral ligament was discovered. Both parts of the ligament were sutured using a locking-loop suture pattern (Kesler type). For additional stability, the suture was protected by figure-eight 80# leader nylon positioned at the collate.
Tibial tuberosity advancement we performed as a second stage of the surgery after medial approach to the proximal tibia. Based on the preoperative measurements using the common tangent method a 12 mm cage was used for the tibial crest advancement
ral ligament attachments. The prosthetic ligament were fixed to the femoral condyle using a bone anchor and passed through a bone tunnel in the fibular head. Both ends of the new ligament were tightened using a dedicated spreadand crimped by  with the joint in extension.unnamedunnamed (1)unnamed (2)

 

 

Dog #2

 

A female mixed breed dog, 4 years old, 12 kg was presented not able to walk after car accident. Fracture of the left humerus was suspected and confirmed by a radiography. Rupture of the urinary bladder was suspected during an abdominal ultrasound and confirmed by a contrast bladder radiographic study. On physical examination a cranial drawer and positive valgus test were noticed on the right knee. Rupture of the medial collateral ligament was confirmed also by stress anterior posterior radiography. On the medial lateral radiograph there were no signs of previous degenerative changes in the stifle joint.

Tie-in external skeletal fixator was used for stabilisation of the midshaft humerus fracture during the first surgery performed together with a laparotomy for suturing of the ruptured urinary bladder. A second surgery was performed for the stifle joint consisting of medial collateral ligament repair and tibial tuberosity transposition. After medial approach to the stifle joint and the proximal tibia, medial arthrotomy confirmed cranial cruciate ligament rupture. No other intraarticular structures were visibly injured. Retracting the caudal part of the sartorius muscle revealed a rupture of the medial collateral ligament close to its insertion on the medial tibial condyle. Because the tear was so severe, a primary reposition of the ligaments was not possible. 40# leader nylon in figure of eight suture was anchored at the medial collateral ligament attachments around two 2.7mm cortical screws and metal washers to prevent suture slippag Tibial tuberosity advancement was performed as a second stage during the surgery. Based on the preoperative measurements using the common tangent method a 7.5 mm cage was used for the tibial crest advancement.

Early postoperative period in both dogs passed without complications. About 10 days after surgery dog #2 was diagnosed also with grade II medial patella luxation in the operated knee and another surgery was performed next. Only this dog was followed for a few monunnamed (4)unnamed (1)unnamedths after surgery when the external fixator from the humerus was removed. The dog recovered to a fully weight bearing with his right hind limb.

Comments

Failure of both the cranial cruciate and the collateral ligament support will result in pain, rapid osteoarthritis progression  and impaired limb function.

The complexity of multiple ligament injury makes the palpation of the joint a bit confusing and could leads to mistakes in diagnosis of cranial vs caudal cruciate ligament rupture. Also because of the possibility of another damaged intra articular structures, an arthrotomy always has to be performed. Collateral ligament injury was first addressed in both cases followed by tibial tuberosity advancement for the failed cranial cruciate ligament. Tibial tuberosity advancement is one of the so called geometry modified procedures in cranial cruciate ligament rupture treatment and seems to be a better choice in cases when also a medial collateral ligament is ruptured. In such a cases positioning of implants (like TPLO plate) on the proximomedial aspect of the tibia will be challenging.

Acknowledgements

 

 

  1. Veterinary surgery: small animal, Tobias K, Johnston. S, 2012, Vol.1

 

  1. Atlas of orthopaedic surgical procedures of the dog and cat, Johnson, A., Dunning, D., 2005

 

  1. Stifle luxation in the dog and cat: The use of temporary intraoperative transarticular pinning to facilitate joint reconstruction, B.Keeley, M.Glyde,S. Guerin, R.Doyle, VCOT, 2007, Vol3

 

  1. Current techniques in small animal surgery, J. Bojrab, D.Waldron, J.Toombs, 2014, 5th edition

 

  1. An atlas of surgical approaches to the bones and joints of the dog and cat, D.Piermattei, K. Johnson, 4th edition, 2004

Spinal Neurofibrosarcoma in a dog- diagnostic, treatment and prognosis

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 Dr Miroslav Todorov , DVM, MRCVS 

Neurosurgeon in Small Animal Veterinary Clinic Blue Cross, Sofia ,Bulgaria

 

 

 

 

Neurofibrosarcomas are malignant nerve sheath tumors that are type of soft tissue sarcomas. They are usually discovered in the peripheral nerves ( most commonly the nerves that are forming the brachial and lumbosacral plexus ). Sometimes they could be discovered in the cranial nerves ( trigeminal, vestibulocochlear ). These tumors are arising from perineural fibroblasts or Schwann cells. They are slow growing and usually locally invasive but are unlikely to metastasize.

5 -years old female dog , Miniature Poodle , was presented for clinical examination. The dog had a long lasting history of difficult movements of the hind limbs. The problem started about 2 months ago, at the beginning only with one limb lameness. The dog had work-up done this problem , including CBC , biochemistry analysis, UA , X-ray, ultrasound of the abdomen and CT of the spine, but not clear visible reason for its condition was discovered. The dog was treated with several drugs, including NSAID , antibiotics, Steroids and Nivalin ( Galantamine hydrobromide ) , but without any successful results.

The dog in general condition , with normal temperature and mild discomfort on  palpation on the abdomen. On the neurological examination : alert mental status, normal cranial reflexes, paraplegic patient, with increase patellar reflexes, and present withdrawal reflexes. There was a mild spinal pain over the spine, localized at the thoracic part of the spine around Th7- Th10 vertebra. The urinary bladder was distended and very hard to express.

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Pic.1

The problem was localized Th3-L3 area of the spinal cord ( Th3-L3 myelopathy ). The most probable diagnosis that could explain the patient’s condition are :          intervertebral disk disease and spinal neoplasia .

Treatment with Prazocin and Bethaneochol was started in order to improve bladder expression and MRI examination was scheduled. With MRI examination was found an ovoid , intradural, extra medullary mass with size 19/11.2 mm that is severely compressing the spinal cord at the level of Th7-Th8. The mass is slightly hyperintensive on T1 and is located on the right side of the spinal cord ( Pic. 1 ) .

After MRI examination the dog lost its deep perception and on the next day was scheduled for surgery. Before the surgery CSF was collected for analysis but the content of the protein and the cell count were normal. The dog had a dorsal laminectomy on the level of the arch of Th7-Th8 vertebra. After opening the spinal canal , a firm, white mass around 15 mm was discovered. ( Pic.2 – black arrows ). After being fully removed  , the mass was send for a histopathological examination.

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Pic. 2

In the post surgical period the dog had painkillers – Morphine/Ketamine/Lidocaine mixture for 5 days and intravenously administrates antibiotics. On the next day the dog regained its deep perception. On the day of its discharge from the hospital it had little movements of its hind limbs and no problem with urination. The owner was adviced about some rehabilitation techniques that he could do at home with the dog and treatment with antibiotics and NSAID was extended for another week. Two weeks later the patient was much better with slight ataxia and a week later – completely normal.

The histopathological result was Neurofibrosarcoma – malignant mesenchymal neoplasia . This type of tumor could reoccur even after a full surgical removal because of the formation of microsatellites.

The localization of this neoplasia is interesting. Usually this tumor grows at the level of brachial or lumbosacral plexuses and it is very uncommon to be found within the spinal canal.

Additional treatment was discussed with the owner. Usually in such cases radiotherapy could be beneficial ( but not available in Bulgaria ) . Additional metronomic chemotherapy with doxorubicin , cyclophosphamide and vincristine , very often in combination with NSAID , could be possible option.

In this case i suggested a combination with NSAID , Meloxicam at dose 0.1mg/kg , Cyclophosphamide 10-15 mg/m^2 q 24hours per os , but the owner declined the second drug, so the dog stay only on meloxicam only.

Unfortunately , two months later the dog came with clinical signs with the same neurolocalization. A new MRI examination and surgery afterwards were suggested to the owner but he declined. He ordered a wheelchair for the dog , to improve her mobility for a short period.

The prognosis of neurofibrosarcoma is guarded. The recurrence of the neoplastic lesion could be expected despite full surgical removal. The usual localization of this neoplasm is within peripheral nerves but sometimes it could be localized inside the spinal canal and look like an intradural extramedullary lesion. The best treatment option is surgical removal and radiotherapy afterwards.