Article — Artikel

Cervical spondylomyelopathy (wobbler syndrome) in the Boerboel

M J Graya*, R M Kirbergera and T C Spotswooda

INTRODUCTION‘Wobbler syndrome’ is a term used to

describe dogs presenting with typicalsymptoms resulting from compression ofthe cervical spinal cord caused by verte-bral malformation, malarticulation, and/or degenerative disease of the surround-ing soft tissues. It is most prevalent inDobermans and Great Danes, but has alsobeen reported in other breeds4,19. Symp-toms include thoracic and pelvic limbataxia and paresis with or without neckpain. Dogs with severe bony deformitiesof the cervical vertebrae tend to presentearlier (usually less than 2 years old)whereas those with more subtle bony oras yet unidentified abnormalities, per-haps leading to instability, generally pres-ent in middle age as a result of degene-rative disc protrusion. Surgical treatmentmay be by ventral slot decompression,dorsal laminectomy, or a variety of dis-traction/fusion techniques1–4,13,14,18,21,27. De-spite surgery, the prognosis remainsguarded. This paper describes wobbler

syndrome in a series of Boerboels, a popu-lar, large, heavy set South African breedthat most closely resembles the Bullmas-tiff.

MATERIALS AND METHODSThe records of the Department of Com-

panion Animal Clinical Studies at theOnderstepoort Veterinary Academic Hos-pital (OVAH) were searched for Boerboeldogs that presented with symptoms ofcervical cord compression between Janu-ary 1998 and April 2003. Only cases wherethe diagnosis was confirmed by diagnos-tic imaging and with complete recordsregarding signalment, history, clinicalpresentation, radiographic findings, andtreatment, were included in the study.Referring veterinarians and/or ownerswere contacted telephonically to ascer-tain the final outcome or current status ifnot apparent from the hospital records.In addition, 1 case was included from aprivate practice where all of the abovecriteria were available from their records.

Radiographic studies had been carriedout in a similar manner for all cases.Sponges were placed under the neck andnose to ensure correct positioning forlateral views. Survey radiographs were

made under general anaesthesia, fol-lowed by a myelogram performed at thecerebello-medullary cistern. A dose ofapproximately 10 m (range 6–15 m ) ofa non-ionic water-soluble contrast me-dium, Iohexol (Omnipaque 300,Saphar-Med), was injected into thesubarachnoid space after collection ofcerebrospinal fluid (CSF) for laboratoryevaluation. One case had a lumbarmyelogram performed. This was fol-lowed by ventrodorsal (VD), dorso-ventral (DV) and lateral exposures. Toallow the contrast medium to gravitate tothe area of interest, VD views were pre-ferred for the cranial cervical region (C4cranially), while DV views were made forcaudal cervical and cranial thoracic areas.In some cases oblique (45°) cervical as wellas dynamic (traction, flexion and exten-sion) views were made under fluoro-scopic guidance.

Magnetic resonance (MR) imaging ofthe brain and cervical spine was per-formed with a 1.5 Tesla unit (SiemensSymphony – Ehrlangen, Germany) underdeep sedation in 1 dog. For the cervicalregion, T1 and T2 weighted images wereacquired followed by intravenous injec-tion of gadoteric acid contrast agent(Dotarem, 1 mmol/kg) and further acqui-sition of T1 weighted images. Contiguoussagittal, transverse and dorsal slices weremade with a slice thickness of 4 mm in thetransverse planes, and 3 mm in the dorsaland sagittal planes.

Diagnostic imaging films were re-viewed by all authors and abnormalitiesrecorded for all cases except one, whereradiographs were not available and infor-mation was obtained from the relevantrecords.

RESULTSTen cases qualified for inclusion in this

study. These included 2 atypical caseswith lesions that did not fit into the con-ventional definition of wobbler syn-drome. They are described separately.The results are summarised in Table 1.

Typical casesFive males and 3 females were affected.

The oldest dog was presented at 2 years ofage. The others were all under 18 monthsat presentation. Weights varied from

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aDepartment of Companion Animal Clinical Studies,Faculty of Veterinary Science, University of Pretoria,Private Bag X04, Onderstepoort, 0110 South Africa.

*Author for correspondence. E-mail: mgray@op.up.ac.za

Received: June 2003. Accepted: October 2003

ABSTRACTThe Boerboel is a South African large-breed dog resembling a Bullmastiff. The records ofOnderstepoort Veterinary Academic Hospital were searched for dogs that had presented,between 1998 and 2003, with symptoms indicative of wobbler syndrome and hadundergone survey radiographic and myelographic studies. Ten cases fitted the inclusioncriteria. Dogs presented within the first 2 years of life, often with acute onset of symptoms.All presented with pelvic limb and 6 with concomitant thoracic limb ataxia or paresis. Treat-ment varied and included none (4), prednisolone (2), and dorsal laminectomy (2). Two dogswere euthanased at the time of diagnosis. The breed appears to be affected with a form ofspondylomyelopathy that comprises bony malformation of cervical and/or thoracic verte-brae. In 8 dogs, malformations were evident on survey radiographs and were characterisedby enlarged, irregular articular facets and associated medial deviation of the pedicles. Thesechanges resulted in axial compression of the spinal cord best seen on ventrodorsal ordorsoventral myelographic studies. Multiple vertebrae were affected in some dogs andlesions were not confined to the caudal area of the cervical spine. Three dogs were alive andwithout symptoms at follow-up. Four were euthanased as a result of the disease and 1 diedas a result of post-operative complications. Two additional dogs presenting with wobblerclinical signs are also described. One had medial deviation of the T5 and T6 caudal pediclesand 1 dog suffered from multiple cervical articular facet synovial cysts.

Key words: boerboel, canine, cervical spondylopathy, CVMM, synovial cysts, wobbler.

Gray M J, Kirberger R M, Spotswood T C Cervical spondylomyelopathy (wobblersyndrome) in the Boerboel. Journal of the South African Veterinary Association (2003) 74(4):104–110 (En.). Department of Companion Animal Clinical Studies, Faculty of VeterinaryScience, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.

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Table 1: Summary of Boerboels with cervical spondylomyelopathy.

No Signalment History Presentation Survey radiographs Myelogram(MR imaging indicated)

Treatment Outcome

Typical cases (n = 8)

1 11 monthsFemale56kg

Intermittent pelvic limb ataxia for1 month. Stiff neck.

Ataxia and CP deficits – pelvic limbs. Medial deviation of caudal pedicle of C4with bulbous facets at C4/5 resulting in25% narrowing of canal on DV view.

VD = mild, bilateral medial deviation andattenuation of L and R CC over caudal C4and C4/5 disc space. Lateral = normal.

None Full recovery

2 12 monthsFemale43 kg

Acute onset; pelvic limb ataxia;lame L thoracic limb.

Hyperreflexic pelvic limbs. CP defi-cits L thoracic and pelvic limbs.

Bulbous facets of C4/5. VD = medial deviation of both CCs atC4/5. Lateral = marked attenuation ofdorsal column and mild attenuation ofventral column C4/5.

Dorsal laminectomyC4/5

Full recovery

3 24 monthsMale52 kg

‘Odd’ gait since birth. Episodes ofneck pain. Occasionally fell over.

Ataxia thoracic and pelvic limbs.Head carriage low. Reflexes withinnormal limits.

Bulbous facets from C4–7. Medial devia-tion of the pedicles which result in caudalconing of canal over these spaces.

VD = mild medial attenuation and deviationof both CCs over C4–7. Lateral = normal.

Prednisolone Euthanasia 4 months later

4 11 monthsMale31 kg

Acute onset, quadriparesis. Ataxia of thoracic and pelvic limbs.CP deficits all limbs.

Mild medial deviation of pedicles C3–4.Mild bulbous facets C3–5.

VD = mild bilateral medial attenuation of CCsC2–4. Lateral = some attenuation of C2/3dorsal CC as well as dorsolaterally in obliqueviews.

None Euthanasia 2 months later

5 11 monthsMale38 kg

Acute onset, intermittentparaparesis/ataxia for 3 weeks.

Hyperreflexic in the pelvic limbs.Proprioceptive deficits R hind limb.

No obvious abnormalities. VD = medial deviation/obliteration of L & Rcontrast columns at C2/3. Lateral = someattenuation of C2/3 dorsal CC Oblique = mildR dorsolateral attenuation and deviation ofthe CC.

None Euthanasia in hospital

6 9 monthsFemale47kg

Acute cervical pain. Ventroflexionof neck.

Cervical pain, pelvic limb ataxia.Normal reflexes.

Caudal narrowing of canal C2 giving coneeffect, bulbous facets at C2/3 causingmarked stenosis of canal.

VD = marked medial deviation of L & R CCsat C2/3. Lateral = normal.

Dorsal laminectomy,partial facetectomy.

Post-operative respiratoryfailure. Died

7 10 monthsMale45 kg

Off balance and scraping nails Lthoracic limb. Progressively worse.

Ataxia L thoracic and both pelviclimbs, falling down.

Medial deviation of cranial and caudalpedicles of C5 with bulbous facets onL at C4–6.

VD = marked medial deviation of left CCs atC4–6 disc areas with minor deviation on rightside. Lateral = normal.

Prednisolone Full recovery

8 17 monthsMale45 kg

Pelvic limb ataxia, lame L forelimb,progressively worse.

Quadriparetic, non-ambulatory,hyperreflexic in pelvic limbs.

Marked medial deviation of the pedicle ofC5. Caudal medial coning of C2, Bulbousfacets at C4–6.

VD = medial deviation of L CC C3/4. Medialdeviation of both CCs at C5/6. (Lumbarmyelogram).

None Euthanasia in hospital.

Atypical cases (n = 2)

9 4 monthsMale20 kg

Pelvic limb ataxia, difficulty rising. Pelvic limb ataxia, Pelvic limb CPdeficits.

Medial deviation of the pedicles at T5 andT6.

Scalloped appearance C3–7 CC. Circumfer-ential attenuation and obliteration of CC overT5 and T6.

Prednisolone Full recovery

10 5 yearsMale54kg

Progressive ataxia and paresis inthoracic and then pelvic limbs.

Quadriparesis, Hyperreflexic inthoracic and pelvic limbs. Non-ambulatory.

No obvious abnormalities. No obvious abnormalities. MR imaging:multiple fluid filled structures associatedwith cervical articulation facets throughoutcervical spine. Largest at L C2/3.

Resection of theC2/3 cyst by dorsallaminectomy

Full recovery

CP = conscious proprioception; VD/DV = ventrodorsal/dorsoventral; CC = contrast column; R = right; L = left.

31–56 kg, which is considered to be nor-mal for the breed. Four dogs showedacute onset of symptoms according to theowners. All presented with evidence ofpelvic limb and 5 with concomitant tho-racic limb ataxia or paresis. Two dogsshowed evidence of cervical pain. Sevenof 8 dogs showed bony changes on surveyradiographs. The most marked changeswere on the VD/DV views, where one ormore of the vertebrae showed narrowingof the vertebral canal due to medial devia-tion of the pedicles that was usually cau-dal and often associated with flared andbulbous articular facets. The C4/5 regionwas affected most often (Fig. 1a). Lateralviews showed bulbous articular facets inmost dogs, although changes were con-sidered mild in some. The facet changescould be seen at a single or multiple verte-bral junctions. Their location ranged fromC2/3 to C6/7 and they were uni- or bilat-eral.

Myelographic studies usually showedno (Fig. 1b) or mild changes on lateralviews. The VD/DV views reflected thechanges seen on survey films with medial

deviation and attenuation of the contrastcolumns adjacent to the medially deviat-ing pedicles (Fig. 1c) and bulbous articularfacets (Figs 1c & 2a). Single or multiple(Fig. 3) sites were involved.

Bulbous articular facets appeared to bethe direct cause of compression in theC2/3 region, possibly due to the shortpedicle length of C2 and wide inter-vertebral foramen found at this space(Fig. 2a). Oblique views, especially in theC2–3 region, showed dorsolateral con-trast column attenuation indicative of adirect articular facet cord compression insome cases (Fig. 2b). Results of CSF analy-sis were within normal limits for all 5cases in which it was evaluated.

Two dogs were discharged withouttreatment at the owner’s request: 1 recov-ered spontaneously and was considerednormal at 18-month telephonic follow-up; the other was euthanased by the re-ferring veterinarian 4 months later due to

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Fig.1: Case 1. a: DV survey view showing medial deviation of thecaudal pedicle of C4 (thick arrows) with bulbous facets at C4–6 (thinarrows). Endotracheal tube present; b: lateral myelogram showingno column attenuation or deviation; c: VD myelogram view withmedial deviation of both contrast columns over caudal C4 and C4/5intervertebral space (arrows).

a a

b

Fig. 2: Case 5. a: Medial deviation of left and right contrast columnsat C2/3; b: oblique myelogram showing mild right dorsolateralattenuation and deviation of the contrast column over C2/3.

Fig. 3: Case 3. VD view showing mild medialattenuation and deviation of both CCs overC4–7.

b

c

a progression of symptoms. A dorsallaminectomy was performed on 2 dogs: 1showed rapid improvement with com-plete recovery and was reported to besymptom-free at 18-month telephonicfollow-up; the other died as a result ofpost-operative respiratory failure.

Two dogs were treated with oralprednisolone (1 mg/kg, duration not re-corded); 1 was euthanased 2 monthslater by the referring veterinarian due toa progression of symptoms; the other hadapparently completely recovered at 11-month telephonic follow-up. Two dogswere euthanased at the owner’s requestafter the diagnosis was made.

Atypical casesOne case was a 4-month-old dog that

presented with a history of progressivepelvic limb ataxia. Clinical evaluationshowed bilateral pelvic limb hyper-reflexia and conscious proprioceptiondeficits. On the myelogram multiple sitesof mild dorsal and ventral contrastcolumn deviation over the interverte-bral spaces (Fig. 4a) were seen. However,the contrast initially stopped abruptly atT5 (Fig. 4b). Medial deviation of thevertebral pedicles of T5 and T6 was be-lieved to be the cause of the clinical signs.The dog was treated with oral predni-silone (1 mg/kg, SID, 7 days) and wasreported by the owner to have made a fullrecovery at 18-month telephonic fol-low-up.

The 2nd dog was presented at 5 years ofage with a history of thoracic limb ataxiathat had progressed to include the pelviclimbs. At presentation he was quadri-paretic and non-ambulatory with pelviclimb hyperreflexia. No lesions were de-tected on survey radiographs and myelo-gram. On MR imaging, the cervical regionshowed multiple cystic structures (hyper-intense on T2 weighted and hypointenseon T1 weighted images) associated withthe articulation facets of C2–7 with nopost-contrast enhancement of these le-sions (Fig. 5a–c). The largest lesion wasseen at the left C2/3 articulation facet, andmeasured 10 × 0.7 mm in the dorsalplane. The lesions became progressivelysmaller further caudally.

A provisional diagnosis of multiple cer-vical intraspinal articular cysts causingextradural cervical cord compression atseveral sites was made. The largest cyst (atC2/3) was excised surgically following adorsal laminectomy. Histopathology con-firmed this to be a synovial cyst. The dogmade a swift and full recovery despite thefact that only the largest lesion wasresected and was reported to be withoutsymptoms at 18-month telephonic fol-low-up.

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a

b

a

b c

Fig. 4: Case 9. a: Lateral myelogram showing multiple sites of cervical dorsal and ventralcontrast column deviation; b: contrast column terminates at caudal T5.

Fig 5: Case 10. a: Left parasaggital T2 weighted MR image showing the focal hyperintense,cyst-like lesions at C2–6 (arrows). All are associated with the left articulation facets. Notethat the lesion is located dorsally at C2/3, laterally at C3/4 and ventrally at C4–6 relative tothe cord. This is most likely due to slight obliquity of the image slice. C3/4 has 2 apparentcysts on either side of the facet joint; b): dorsal T2 weighted image showing bilateralhyperintense, cyst-like lesions associated with the articulation facets of C2/3dorsolaterally and C3/4 laterally. The lesions (arrows) were dorsolaterally and laterallylocated at this level; c: dorsal T2 weighted image made in a plane 6 mm ventral to the imagein Fig 5b. Bilateral hyperintense, cyst-like lesions (arrows) associated with the articulationfacets of C3–5 are seen. The C2/3 cysts identified in Fig 5(b) are outside the imaging plane.

DISCUSSIONThe Boerboel is a popular and estab-

lished South African large-breed dog ofmixed ancestry. It has been exported tothe United States, Netherlands and someother countries. Boerboel is an Afrikaansword and directly translated means‘farmer bull’. Jan van Riebeeck, who ar-rived from Holland in the Cape in 1652,brought with him a ‘bullenbijter ’ and this,together with many other large breedssuch as bulldogs and mastiff typesbrought to South Africa by British settlersprobably contributed to its ancestry11.There is some variation in the size andconformation, but they are generallyheavyset dogs weighing between 35 and55 kg at maturity. The appearance of wob-bler syndrome in this breed appears to bea fairly recent phenomenon and isthought to have become quite common.The 8 confirmed cases over a period of 5years were fewer than expected consider-ing the popularity of the breed. This mayreflect the severity of symptoms and poorprognosis offered by veterinarians thatresults in euthanasia rather than referral,success with conservative management,or failure to diagnose the condition.

Wobbler syndrome has been classicallydefined as the typical symptoms of ataxiaand tetraparesis that result from compres-sion of the caudal cervical spinal cordcaused by malformation/malarticulationand/or degenerative disease14. The varia-tion in lesions encountered and the un-certainty that surrounds the aetiopatho-genesis has led to many names for thiscondition, including cervical vertebralmalformation/malarticulation (CVMM),and cervical vertebral instability3,8,14,18,23.Lesions occurring as far cranially as C2/3and C3/4 have been included in studiesusing the name ‘caudal cervical spon-dylomyelopathy (CCSM) or spondylo-pathy5,8. Cervical spondylopathy orspondylomyelopathy7,17,19,22 are terms pre-ferred by the authors for malforma-tion-associated wobblers (see below)since they do not make reference to theposition in the cervical column, allowinga broader definition that can also includerecently described conditions causingsimilar symptoms, such as synovial cysts.The cases reported here had lesions thatwere not limited to the caudal cervicalarea. The term ‘wobbler syndrome’ hasbeen widely accepted because it is de-scriptive of the symptoms without impli-cation of a single aetiology14,26,27.

Genetic predisposition is likely, giventhe preponderance of certain breeds7.Those most often quoted as being predis-posed to wobbler syndrome are theDoberman and Great Dane20,26. The syn-drome has, however, been diagnosed in

many others, including Basset Hounds,Rottweilers, Boxers, Rhodesian Ridge-backs and English Mastiffs7,8,30. It has beenproposed that bony malformations maybe a response to early vertebral instabil-ity26. Other factors that have been impli-cated include over-nutrition, over-supplementation with calcium and headweight/carriage12,13,30. The diagnosis is sus-pected on the basis of signalment, clinicalsigns, and neurological examination, andconfirmed using diagnostic imagingstudies such as myelography and MRimaging. The presenting symptoms areusually pelvic limb paresis and/or ataxiawith or without thoracic limb involve-ment26. Some individuals show signs ofneck pain. The acute onset of symptomsreported in the current study is consistentwith previous reports, and is probablydue to a relatively minor traumatic inci-dent that causes marked cord compres-sion as a result of the compromised spacewithin the canal14. Neurological symp-toms may include limb hyperreflexiaand proprioceptive or postural deficits.Evaluation of CSF is performed to ruleout infectious or inflammatory disease.

It is usually possible to identify lesionssuch as spondylosis, collapse of the discspace, vertebral tipping/malalignment,degenerative changes or malformation ofthe articular facets, vertebral stenosis,malarticulation, proliferation of bonearound synovial joints, and malformedvertebrae on survey radiographs14,27.These can mostly be diagnosed fromlateral views. Pedicle malformationscan only be seen on DV/VD views andthese are thus essential for diagnosticpurposes21. This is well illustrated in thecurrent study where medial deviation ofpedicles was seen in 5 of the 8 typicalcases. Lesions identified on survey radio-graphs do not always correlate with thesite of compression, so myelography isessential to confirm the diagnosis andlocalise the lesion14,20,26. One of the 8 typi-cal cases reported here showed no abnor-malities on survey films. It is possible thatthe cord compression evident on myelo-gram in this case was due to soft tissuepathology such as intraspinal articularcysts (see atypical cases) as neither sur-gery nor MR imaging was performed.

Myelography will define extraduralcompression(s) that results from disc ex-trusion or protrusion, ligamentumflavum hypertrophy and vertebral mal-formation or malalignment26,27. Myelo-graphic traction studies can also beperformed to determine whether thelesion is traction-responsive or not, sincethis may influence the type of surgeryperformed. It is interesting to note that, inthis study, 5 of 8 typical cases showed no

abnormalities on lateral myelographicview, highlighting the need to makeVD/DV views. Oblique projections pro-vide valuable additional information incircumferential lesion localisation andoblique myelographic views are nowperformed routinely at the OVAH whenperforming large-breed myelograms tomore accurately describe the pathologicalsite.

Multiple lesions (50 % of dogs in thisseries) may be missed if sufficient contrastdoes not bypass the initial site/s of com-pression. Elevating the head will assistthe flow of contrast medium caudally.Failing this, a lumbar myelogram shouldbe considered. No cervical myelographicstudy is thus complete unless the wholecervical region, and preferably the cranialthoracic region, is adequately opacifiedwith contrast medium and lateral, VD/DVand oblique views have been made.

Attempts to classify wobblers intowell-defined clinical categories is compli-cated by considerable overlap. Myelo-pathy can result from any one or combi-nation of the aforementioned lesions. It isuseful to simplify the classification into 2major groups that are usually quitedistinct14:1. Immature dogs that have structural

bony malformation leading to steno-sis of the vertebral canal (malforma-tion-associated wobblers)26. GreatDanes and Dobermans are most fre-quently affected14,23,26. There appearsto be an overall decrease in the inci-dence of this type of wobbler, perhapsdue to their early identification andremoval from the gene pool24,27.Where wobbler syndrome affectsother breeds, they also usually fall intothis category.

2. Middle-aged or older dogs that havedegenerative cervical disc diseasewith acquired compression of the cer-vical spinal cord (disc-associatedwobblers).

This group is largely represented bymiddle-aged Dobermans. Stenosis ofthe bony part of the canal is oftenpresent but is mild and symptoms arethought to be due to subsequent insta-bility and degenerative changes of thesupporting structures, such as theligamentum flavum and interverte-bral discs that undergo a Hansen type2 disc protrusion14,17,27,30.

The Boerboels in this limited studyclearly fit into the 1st group. All typicalcases were 2 years of age or youngerwhen presented. Most showed similarbony deformities on survey radiographs,with the exception of the single case inwhich no abnormalities were detected.The vertebral canal was narrowed by

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medial deviation of the pedicles, whichwas associated with bulbous articularfacets. These changes are similar to thosedescribed in young Great Danes14,21,26,29,30.The abnormal vertebral body conforma-tions reported in the Doberman and GreatDane were, however, not evident in thisseries, and the ‘hourglass’ compressionthat results from ligamentum flavum anddorsal annulus hypertrophy, hyperplasia,or redundancy was only evident in 1case3,23,26,30. The lack of dorsoventral com-pression on the myelographic studiessuggests that shortened pedicles were nota feature of the current series. Inter-vertebral discs showed no obvious signsof degeneration. Cord compression ap-peared to originate from the mediallydeviated pedicles and enlarged articularfacets described above. It was worse at thecaudal extent of the vertebrae and overthe intervertebral disc spaces. Multiplecervical vertebrae were affected in 4 dogs.

Although bony abnormalities may re-sult in narrowing of the vertebral canal,other studies have shown that it is notuncommon to find that the compressionof the cord is dynamic in nature17,23. Trac-tion studies were not carried out in thisseries, but intuitively it would seemunlikely that lesions causing lateral steno-sis of the type described here would betraction responsive.

Two cases that would traditionally notbe considered wobblers were included inthe study because they presented withsymptoms indistinguishable from classicwobblers. The one case was diagnosedwith cervical synovial cysts, a conditionaffecting mainly large and giant-breeddogs9,16. Dickinson et al.9 identified 2groups in a series of 9 dogs: (1) young,giant-breed dogs with multiple cysts in-volving one or more levels of the cervicalspinal cord; and (2) older, large-breeddogs with a solitary cyst involving thethoracolumbar spinal cord. The synovialcysts constituted the major compressivelesions in 4 of the 9 dogs. Despite beingpresented at 5 years of age, the casedescribed in this article would best fit intothe 1st group, with severe compression atthe C2–3 site. It is interesting to notethat 3 of the 4 dogs diagnosed with cervi-cal synovial cysts described by Levitskiet al.16, and 3 of the 6 dogs described byDickinson et al.9, were mastiffs.

Synovial cysts are believed to be associ-ated with degeneration of the articulationfacet joints and articular facet spondyl-arthrosis is considered to be an importantsentinel radiological sign of synovialcysts16. In the current case, no degenera-tive changes of the facet joints were notedon survey radiographs and no compres-sion was seen on lateral and DV/VD

myelographic views. The dorsolaterallylocated lesions were only seen with MRimaging even though oblique myelo-graphic views were performed.

Two types of intraspinal articular (facetjoint) cysts have been described in dogs:synovial cysts and ganglion cysts28.Synovial cysts have a synovial-like celllining and communicate with a joint,whereas ganglion cysts do not6. Webbet al.28 recommend that these cysts shouldbe referred to as intraspinal articular cystsuntil histological confirmation. It is quitepossible that cases diagnosed with dorsalcompressive spinal lesions on myelo-graphy (and attributed only to facetchanges or ligamentous and soft tissuehypertrophy), may in fact have synovialcysts contributing significantly to thecompression9. Synovial cysts must be con-sidered as a differential diagnosis in anylarge-breed dog presenting with cervicalmyelopathy and MR imaging should beconsidered as the primary diagnostic toolto identify these cases16.

The other atypical case was diagnosedwith lateral cord compression by mediallydeviating pedicles in the cranial thoracicregion at T4–5 and T5–6. It is the authors’experience that these lesions tend to bechallenging to diagnose, even on goodquality VD survey radiographs, due to thesuperimposition of the soft tissues of theepaxial muscles and cranial mediastinum.They are easily missed if not specificallysought, but myelography is very useful indemonstrating the cord compression. Inthis case the lateral compression wassevere enough to result in an initial halt tocontrast flow at the cranial compressionsite, followed by poor subarachnoidcontrast filling over the sites of compres-sion on the lateral views. Unfortunately,oblique myelographic views were notperformed in this dog.

Treatment of wobbler syndrome isdependent on the cause and location ofthe compression and whether the lesionis dynamic or static. There are few reportson the success of conservative therapy,which may be attempted for mild casesand includes the use of cage rest, neckbraces, and corticosteroids3,7,10,15,20,23,26.Nineteen of 25 dogs that were not treatedin one study were euthanased due toprogression of symptoms7. Ventral slotdecompression and distraction/fusiontechniques are most commonly em-ployed for single ventral lesions1,2,5,10,22,30.Dorsal laminectomy is best suited tomultiple lesions or bony deformities suchas those described in this report23,30. Thistechnique has been associated withvaried success3,20. A recent report8, how-ever, recorded a good or excellent resultin 19 of 20 dogs that undewent dorsal

laminectomy, with a return to optimalneurological status within 2 weeks to 12months. The minimum follow-up timewas 7 months, with 3 dogs having recur-rence of symptoms. In the same study, 5of 8 young dogs with congenital osseusmalformation or hourglass compressionmade good or excellent recoveries, withno relapse at follow-up, which rangedfrom 1–9 years. All 5 were ambulatorypreoperatively. Of the other 3 dogs, 1made a good initial recovery but suffereda relapse 4 months after surgery and wasmanaged successfully by conservativemeans, 1 was euthanased after an initialrecovery as a result of suspected recur-rence, and 1 was worse after surgery anddid not regain pre-surgical status8.Another study recorded a good or excel-lent recovery in 16 of 19 cases that under-went dorsal laminectomy for cervicalmalformation/malarticulation25. Thesmall number of cases and variability inmanagement does not allow for prognos-tication in the current study. The fact thatonly 2 dogs were treated surgically mayreflect the guarded to poor prognosisoffered to owners and/or the high cost in-volved. Small numbers in other studiesalso make evaluation difficult, but sur-gery may offer a somewhat better prog-nosis than is generally perceived8.

Wobbler syndrome should be placedhigh on the differential diagnosis listwhen a Boerboel is presented withsuggestive signalment and symptoms.Cervical synovial cysts or ‘wobbler ’lesions in the cranial thoracic spineshould also be considered. In addition tosurvey radiographs, further diagnosticimaging is mandatory. Myelographyshould include lateral, DV (caudal cervi-cal), VD (cranial cervical), oblique, andtraction views. The study should extendat least to the cranial thoracic vertebrae. Acomputed tomography or MR imagingstudy may be performed instead ofmyelography and should be consideredwhen a myelogram shows no cord com-pression. Dynamic studies using thesemodalities have been described19.

ACKNOWLEDGEMENTSThe authors would like to thank the

veterinarians who referred cases, A DHamman and M Koegelenberg for theirassistance in researching hospital data,and the Westville Veterinary Hospital formaking their records available.

REFERENCES1. Bruecker K A, Seim H B, Blass C E 1989 Cau-

dal cervical spondylomyelopathy: decom-pression by linear traction and stabilizationwith Steinman pins and polymethylmethacrylate. Journal of the American AnimalHospital Association 25: 677–683

110 0038-2809 Tydskr.S.Afr.vet.Ver. (2003) 74(4): 104–110

2. Bruecker K A, Seim H B, Withrow S J 1989Clinical evaluation of three surgical meth-ods for treatment of caudal cervical spon-dylomyelopathy of dogs. Veterinary Surgery18: 197–203

3. Bruecker K A, Seim H B 1993 Caudal cervi-cal spondylomyelopathy. In Slatter D (ed.)Textbook of small animal surgery (2nd edn)W B Saunders, Philadelphia: 1056–1070

4. Chambers J N, Betts C W 1977 Caudal cervi-cal spondylopathy in the dog: a review of 20clinical cases and the literature. Journal of theAmerican Animal Hospital Association 13:571–576

5. Chambers J N, Bjorling D E 1986 Update onventral decompression for caudal cervicaldisk herniation in Doberman Pinchers.Journal of the American Animal Hospital Asso-ciation 22: 775–778

6. Cho K O, Park N Y, Kang M I, Umemura K,Itakura C 2000 Ganglion cysts in a juveniledog. Veterinary Pathology 37: 340–343

7. Denny H R, Gibbs C, Gaskell C J 1977 Cervi-cal spondylopathy in the dog – a review ofthirty five cases. Journal of Small Animal Prac-tice 18: 117–132

8. De Risio L, Munana K, Murray M, Olby N,Sharp NJH, Cuddon P 2002 Dorsal laminec-tomy for caudal cervical spondylomyelo-pathy: postoperative recovery and long-term follow-up in 20 dogs. Veterinary Sur-gery 31: 418–427

9. Dickinson P J, Sturges B K, Berry W L,Vernau K M, Koblik P D, Lecouteur R A 2001Extradural spinal synovial cysts in ninedogs. Journal of Small Animal Practice 42:502–509

10. Dixon B C, Tomlinson J L, Kraus K H 1996Modified distraction-stabilisation tech-nique using an interbody polymethylmethacrylate plug in dogs with caudal cer-vical spondylomyelopathy. Journal of theAmerican Veterinary Medical Association 208:61–68

11. Grabe G 1995 Die Boerboele van Suidelike-Afrika. Meat Board, South Africa: 7

12. Hazewinkel H A W, Goedegebuure S A,Poulos P W, Wolwekamp W T C 1985 Influ-ences of chronic calcium excess in the skele-tal development of growing Great Danes.Journal of the American Animal Hospital Asso-ciation 21: 377–391

13. Hedhammer A, Wu F, Krook L et al. 1974Over-nutrition and skeletal disease: anexperimental study in growing Great Danedogs. Cornell Veterinary 64 (Supplement 5):1–130

14. Jeffery N J 1995 Handbook of small animalspinal surgery. W B Saunders, Philadelphia:169–184

15. Jeffery N J, McKee W M 2001 Surgery fordisc-associated wobbler syndrome in thedog – an examination of the controversy.Journal of Small Animal Practice 42: 574–581

16. Levitski R E, Chauvet A E, Lipsitz D 1999Cervical myelopathy associated with extra-dural synovial cysts in 4 dogs. Journal ofVeterinary Internal Medicine 13: 181–186

17. Lewis D G 1991 Radiological assessment ofthe cervical spine of the Doberman withreference to cervical spondylomyelopathy.Journal of Small Animal Practice 32: 75–82

18. Lincoln J D 1992 Cervical vertebral malfor-mation/malarticulation syndrome in largedogs. Veterinary Clinics of North America –Small Animal Practice 22: 923–935

19. McKee W M, Sharp N J H 2003 Cervicalspondylopathy. In Slatter D (ed) Textbook ofsmall animal surgery (3rd edn) . W BSaunders, Philadelphia: 1180–1192

20. Read R A, Robins G M, Carlisle C H 1983Caudal cervical spondylo-myelopathy(wobbler syndrome) in the dog: a review ofthirty cases. Journal of Small Animal Practice24: 605–621

21. Rendano V T, Smith L L 1981 Cervical verte-bral malformation-malarticulation (Wob-bler Syndrome) – the value of the ventro-

dorsal view in defining lateral spinal cordcompression in the dog. Journal of the Ameri-can Animal Hospital Association 17: 627–634

22. Rusbridge C, Wheeler S J 1998 Comparisonof two surgical techniques for the manage-ment of cervical spondylomyelopathy inDobermans. Journal of Small Animal Practice39: 425–431

23. Seim H B, Bruecker K A 1993 Caudal cervi-cal spondylomyelopathy: wobbler syn-drome. In Bojrab M J (ed.) Disease mecha-nisms in small animal surgery (2nd edn).Lippincott, Philadelphia: 979–983

24. Sharp N J H, Wheeler S J, Cofone M 1992Radiological evaluation of ‘wobbler’ syn-drome – caudal cervical spondylomyelo-pathy. Journal of Small Animal Practice 33:491–499

25. Trotter E J, deLahunta A, Geary J C, BrasmerT H 1976 Caudal cervical vertebral malfor-mation-malarticulation in Great Danes andDoberman Pinchers. Journal of the AmericanVeterinary Medical Association 168: 917–930

26. Trotter E J 1985 Canine wobbler syndrome.In Newton C D, Nunamaker D M (eds) Text-book of small animal orthopaedics. Lippincott,Philadelphia: 765–790

27. VanGundy T E 1988 Disc-associated wob-bler syndrome in the Doberman Pincher.Veterinary Clinics of North America – SmallAnimal Practice 18: 667–695

28. Webb A A, Pharr J W, Lew L J, Tryon K A2001 MR imaging findings in a dog withlumbar ganglion cysts. Veterinary Radiology& Ultrasound 42: 9–13

29. Wheeler S J 1994 Small animal spinal disor-ders. Mosby-Wolfe, London

30. Wright F, Rest J R, Palmer A C 1973 Ataxia ofthe Great Dane caused by stenosis of thecervical vertebral canal: comparison withsimilar conditions in the Basset Hound,Doberman Pincher, Ridgeback and theThoroughbred horse. The Veterinary Record92: 1–5