Angela Hartman

Degenerative lumbosacral stenosis in working dogs: Current concepts and review

Abstract Extract Degenerative lumbosacral stenosis (DLSS) is a common condition amongst active large-breed dogs, and has a complex aetiopathogenesis. Diagnosis is hampered by subtle clinical signs which may be confused for other neurological or orthopaedic conditions. Signalment and specific manipulative tests allow the clinician to form a high suspicion for DLSS and initiate investigation, however plain radiographic findings are not pathognomic. Advanced imaging is considered essential for an accurate diagnosis but may highlight non-symptomatic lesions, therefore clinical judgement remains paramount. Medical management of mild cases is generally considered to be satisfactory for pet animals, for which modification of their lifestyle is possible. However, return to an acceptable level of performance requires surgical intervention in most working dogs. Whilst some prognostic indicators have been identified, recurrence is common, and many questions remain as to the best method of surgical management. Three-dimensional reconstructive computed tomography (CT) has introduced a new means of indirectly visualising the neuroforamina that exit at the lumbosacral space. This review covers the current state of knowledge of DLSS in dogs, and attempts to identify areas for future study regarding dynamic instability and changes to the lumbosacral neuroforamina at the extremes of joint motion.

Comparison between a novel bovine xenoimplant and autogenous cancellous bone graft in tibial tuberosity advancement.

OBJECTIVE To compare radiographic healing and clinical outcome of a frontal-opening wedge osteotomy of canine tibiae when the osteotomy site is packed with either a novel bovine xenograft or standard autogenous cancellous bone graft (ACBG). STUDY DESIGN Cohort study. ANIMALS Dogs (n = 82) with partial or complete rupture of the cranial cruciate ligament that had tibial tuberosity advancement (TTA). METHODS In 48 dogs, the osteotomy was packed with a novel bovine xenograft and in 34 dogs, ACBG was used. Eight week postoperative radiographs from both groups were graded for osteotomy healing using a 0-4-point scale. Data were analyzed using a Mann-Whitney test with significance set at P < .05. RESULTS Thirty-four dogs (39 stifles) with xenoimplants had complete records and radiographic follow-up at 8 weeks. No significant differences between xenografting and autografting were identified in grading of osteotomy fill, osteointegration, or healing of the distal osteotomy. Significant differences were noted in grading of osteotomy healing proximally (autograft > xenoimplant) and of opacity in the osteotomy site (xenoimplant > autograft). CONCLUSIONS Radiographic evidence of healing of the xenoimplanted portion of the TTA osteotomy was equivalent to results with ACBG. Healing of the proximal osteotomy site (above the cage) was improved when ACBG was used as the graft.

Bilateral carpal valgus deformity in hand‐reared cheetah cubs (Acinonyx jubatus)

Four hand-reared cheetah cubs (Acinonyx jubatus) exhibited progressively severe bilateral valgus deformity of the carpi (CV) during the weaning period. Radiographs of the thoracic limbs suggested normal bone ossification, and serum chemistry was unremarkable. All affected cubs developed CV shortly after the onset of gastroenteritis, which was treated medically, and included use of a prescription diet. A sudden decrease in growth rate was associated with gastrointestinal disease. Before gastroenteritis and CV, affected cubs had higher growth rates than unaffected cubs, despite similar mean daily energy intake. Return to normal thoracic limb conformation was consequent to dietary manipulation (including a reduction in energy intake and vitamin and mineral supplementation), as well as decreased growth rates and recovery from gastroenteritis. The cause of the CV is likely to have been multi-factorial with potentially complex physiological interactions involved.

Computed tomographic evaluation of dynamic alteration of the canine lumbosacral intervertebral neurovascular foramina.

OBJECTIVE To develop a computed tomographic (CT) method to measure the volume of the lumbosacral intervertebral neurovascular foramina (IVF) in dogs, and determine the effect of the range of motion of the lumbosacral (LS) junction on this measurement in German shepherd dogs (GSDs) with degenerative lumbosacral stenosis (DLSS) compared to unaffected controls. STUDY DESIGN In vivo analysis and retrospective case series. SAMPLE POPULATION Twenty-four working Police GSDs, 12 diagnosed with DLSS and 12 unaffected by DLSS were compared to 10 Greyhounds without DLSS. METHODS Three-dimensional renderings of CT data were used to measure the lumbosacral foraminal volume of dogs positioned in dorsal recumbency with the LS junction alternately positioned in extension, neutral position, and flexion. RESULTS Volumetric analysis of the IVF was found repeatable for the extended and neutral positions (interclass correlation coefficient of 0.89 and 0.8, respectively). The mean lumbosacral IVF volume was decreased by 74% between LS flexion and extension in Greyhounds, compared to 79 and 85% reductions in GSDs unaffected and affected by DLSS, respectively. The lumbosacral IVF volume was decreased by 23% when comparing extended to neutral LS positions in Greyhounds, 29% in unaffected GSDs, and 31% in affected GSDs. IVF volumes were smaller in affected GSDs compared to unaffected GSDs (P < .05) and Greyhounds (P < .01). CONCLUSIONS Positioning the LS junction in full extension decreases the volume of the lumbosacral IVF. This dynamic narrowing was more pronounced in GSDs with signs of DLSS than in GSDs not overtly affected by DLSS.

Choanal atresia in a cat.

CASE HISTORY: A 5-month-old domestic shorthair kitten with a history of chronic left unilateral nasal discharge was examined. CLINICAL FINDINGS: Endoscopy and computed tomography (CT) demonstrated a complete membranous obstruction of the left nasal choana, confirming congenital unilateral choanal atresia. In addition, congenital hydrocephalus was detected on CT. Nasopharyngoscopy was performed for confirmation and treatment of choanal atresia. DIAGNOSIS: Unilateral membranous choanal atresia associated with congenital hydrocephalus. CLINICAL RELEVANCE: This report describes a rare congenital condition and for the first time, CT imaging provided an accurate diagnosis and allowed planning for the successful treatment of unilateral membranous choanal atresia. In addition, concurrent congenital hydrocephalus was diagnosed.

Computed tomographic method for measurement of inclination angles and motion of the sacroiliac joints in German Shepherd Dogs and Greyhounds

OBJECTIVE To develop an in vivo CT method to measure inclination angles and motion of the sacroiliac joints in dogs of performance breeds. ANIMALS 10 German Shepherd Dogs and 12 Greyhounds without signs of lumbosacral region pain or neurologic problems. PROCEDURES CT of the ilium and sacrum was performed in flexed, neutral, and extended hind limb positions. Lines were drawn on volume-rendered images acquired in the flexed and extended positions to measure motion of the ilia relative to the sacra. Inclination angles of the synovial and ligamentous components of the sacroiliac joints were measured on transverse-plane CT images acquired at cranial and caudal locations. Coefficients of variance of measurements were calculated to determine intraobserver variability. RESULTS Coefficients of variance of measurements ranged from 0.17% to 2.45%. A significantly higher amount of sacroiliac joint rotational motion was detected for German Shepherd Dogs versus Greyhounds. The cranial synovial joint component had a significantly more sagittal orientation in German Shepherd Dogs versus Greyhounds. No significant differences were detected between breeds for x- or y-axis translational motion or caudal synovial or ligamentous joint component inclination angles. CONCLUSIONS AND CLINICAL RELEVANCE The small amounts of sacroiliac joint motion detected in this study may buffer high-frequency vibrations during movement of dogs. Differences detected between breeds may be associated with the predisposition of German Shepherd Dogs to develop lumbosacral region signs of pain, although the biological importance of this finding was not determined. Future studies are warranted to compare sacroiliac joint variables between German Shepherd Dogs with and without lumbosacral region signs of pain.

Medium-Term Outcome and CT Assessment of Lateral Foraminotomy at the Lumbosacral Junction in Dogs with Degenerative Lumbosacral Stenosis

OBJECTIVE  This article aims to report the medium-term clinical outcome and assess persistence of enlargement of the lumbosacral lateral intervertebral neurovascular foramen using computed tomography (CT) volumetric analysis in dogs following lateral foraminotomy. MATERIALS  Six dogs that underwent lumbosacral lateral foraminotomy on one or both sides were evaluated with CT prior to, immediately postoperatively (n = 2) and at 12 to 44 months of follow-up. Five out of six dogs had successful clinical outcomes with alleviation of pain and increased levels of activity, according to subjective assessment. Immediate postoperative CT volumetric analysis of the lateral intervertebral neurovascular foramina in two dogs indicated a 650 to 800% increase in volume in extension achieved by foraminotomy (four foramens). At subsequent follow-up, bone regrowth had occurred with reduction in foraminal volume, though in both dogs foraminal volume remained higher than preoperative values. Follow-up CT at a median of 24 months postoperatively indicated a mean 335% increase in volume of the lumbosacral lateral intervertebral neurovascular foramina in extension compared with the preoperative foraminal volume. The follow-up volume was substantially greater than the presurgical volume in four out of six dogs. CLINICAL SIGNIFICANCE  In this limited case series, lateral foraminotomy achieved persistent enlargement of the lumbosacral lateral intervertebral neurovascular foramen in the medium term, but osseous regrowth at the site was demonstrated which may limit the effectiveness of lateral foraminotomy in the longer term. One of two working dogs had recurrent clinical signs that necessitated further surgery.

Effect of dorsal laminectomy and dorsal annulectomy with partial lumbosacral discectomy on the volume of the lateral intervertebral neuroforamina in dogs when the lumbosacral junction is extended

OBJECTIVE To determine the effect of dorsal annulectomy and partial discectomy on the volume of the lumbosacral lateral intervertebral neurovascular foramina (intervertebral foramina) in canine cadavers during extension of the lumbosacral junction. STUDY DESIGN Ex vivo experiment. SAMPLE POPULATION Lumbosacral specimens from 10 large breed dogs euthanatized for reasons unrelated to lumbosacral disease. METHODS The lumbosacral specimens were clamped in a wooden jig and scanned using computed tomography (CT) with the lumbosacral junction in a neutral position and loaded in extension using a tensioning device. The 3-dimensional volumes of the lumbosacral intervertebral neurovascular foramina were measured and the extent of any disc degeneration was determined from the CT data. A limited dorsal laminectomy of S1 and a dorsal LS annulectomy and partial discectomy were then performed. The lumbosacral specimens were remounted into the jig and loaded into extension at the same tension and were re-scanned. Measurements of intervertebral foraminal volume were then repeated. RESULTS The mean volume of the lumbosacral foramina (n = 20) was 381 mm3 in neutral (unloaded) positioning and 137 mm3 when loaded in extension. Following dorsal annulectomy, the mean volume was significantly reduced by a mean of 28% to 98 mm3 (P < .01). The foraminal volume was reduced in 19/20 lumbosacral foramen, with the post-annulectomy volume ranging from 31% to 97% of the pre-annulectomy volume (3%-69% reduction). CONCLUSIONS This study suggests that a dorsal annulectomy with partial discectomy may induce further dynamic collapse of the lumbosacral articulation in the dog.

Transcoelomic spread and metastasis of a squamous cell carcinoma of presumed pancreatic duct origin in a cat.

Abstract CASE HISTORY: A 13-year-old female spayed domestic shorthaired cat was examined because of lethargy, inappetance and weight loss. CLINICAL FINDINGS: No clinically significant haematological or biochemical abnormalities were detected, but an abdominal mass was palpated. Abdominal examination using ultrasonography revealed soft tissue masses in the cranial abdomen, involving the spleen, as well as the liver and abdominal wall; the pancreas was not identified. Despite supportive therapy the condition of the cat rapidly deteriorated and euthanasia was performed. PATHOLOGICAL FINDINGS: Cytological preparations from the cranial abdominal mass revealed a population of pleomorphic epithelial cells consistent with a squamous cell carcinoma. On post-mortem examination, firm creamy white to yellow nodular masses were present in the region of the pancreatic left limb, spleen, liver, diaphragm, right abdominal wall and in the left lung. Sections of all masses were examined histopathologically and demonstrated infiltration by neoplastic epithelial cells indicative of squamous cell carcinoma (SCC). DIAGNOSIS: Squamous cell carcinoma of presumed pancreatic duct origin. CLINICAL RELEVANCE: There are few reports of haematogenous or lymphatic metastasis of SCC in cats, and none reporting transcoelomic spread. This report describes the clinical and pathological features of a case of presumed primary pancreatic ductal SCC, and should alert veterinarians to the potential for metastasis and carcinomatosis.

Probable avulsion of the infraspinatus tendon of insertion in a Rottweiler

Abstract CASE HISTORY: An 8.5-month-old male Rottweiler was presented with chronic, non-localisable, right forelimb lameness. CLINICAL FINDINGS: Survey radiographs revealed panosteitis in the right antebrachium and an irregularly marginated radiolucency on the lateral aspect of the proximal left humerus. The tendon of insertion of the left infraspinatus muscle was enlarged, some tendon fibres ended prematurely in a cluster of mineralised particles, and there was a large bony defect at the point of insertion. DIAGNOSIS: Probable avulsion of the left infraspinatus tendon. CLINICAL RELEVANCE: This case was particularly unusual due to the marked prominence of the lesion without lameness of the left forelimb. Avulsion of the infraspinatus tendon is poorly described in the veterinary and medical literature.