Surgical treatment of degenerative lumbosacral stenosis in dogs

OBJECTIVE: To study the epidemiology, clinical findings, and long-term outcome of surgical treatment of degenerative lumbosacral stenosis (DLSS) in dogs. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: 131 client-owned dogs with DLSS. METHODS: The medical records of dogs with DLSS treated by dorsal laminectomy and dorsal fenestration were reviewed. The clinical diagnosis had been verified by diskography, epidurography or myelography, or a combination thereof. RESULTS: The German shepherd breed was over-represented (56.5%), and males were more often affected than females (2:1). Historically, reluctance or pain when jumping, rising from a prone position, or climbing stairs (92.4%) and signs of pain or stiffness during extensive physical activity (85.5%) were the most frequent concerns. The most common physical and neurologic examination findings were pain in the lumbosacral area during hyperextension (97.7%) and on direct digital palpation (84.7%). A total of 93.2% of the dogs were improved clinically within the follow-up period (mean 26 +/- 17 months). Recurrence of clinical signs resembling DLSS was reported by the owner or diagnosed by clinical examination in 17.6% of the dogs with a mean onset of signs at 18 +/- 13 months postoperatively. CONCLUSIONS: Surgical treatment of DLSS with dorsal laminectomy and fenestration generally resulted in good to excellent clinical outcome.     

Imaging findings and surgical treatment of hemivertebrae in three dogs

CASE DESCRIPTION: 3 immature screw-tailed dogs were evaluated because of progressive pelvic limb paraparesis. CLINICAL FINDINGS: Each dog had marked ataxia and paresis of the pelvic limbs and a palpable deformity of the midthoracic portion of the vertebral column. Pain perception in the pelvic limbs was considered normal, and there was no evidence of fecal or urinary incontinence in any of the 3 dogs. Radiography and magnetic resonance imaging revealed hemivertebrae with severe dorsoventral stenosis of the vertebral canal resulting in spinal cord compression in 2 dogs and lateral compression in the other. TREATMENT AND OUTCOME: Each dog underwent decompressive surgery consisting of dorsal laminectomy or hemilaminectomy and vertebral stabilization by use of combinations of Kirschner wires or threaded external fixator pins plus polymethylmethacrylate bone cement. All dogs regained strong locomotor function with minimal residual pelvic limb ataxia. CLINICAL RELEVANCE: Little detailed information regarding surgical treatment of hemivertebrae in dogs is available; results of treatment in these 3 dogs suggest that spinal cord decompression and stabilization of the vertebral column can achieve a satisfactory, functional outcome.     

Surgical treatment of lumbosacral foraminal stenosis using a lateral approach in twenty dogs with degenerative lumbosacral stenosis

Objectives— To describe clinical signs, magnetic resonance imaging (MRI) and surgical findings using a lateral approach to the lumbosacral intervertebral foramen and to evaluate clinical outcomes in dogs with or without concurrent dorsal decompression and annulectomy.
Study Design— Retrospective study.
Animals— Dogs (n=20) with degenerative lumbosacral stenosis (DLSS).
Methods— Medical records (2002–2006) of dogs that had lumbosacral lateral foraminotomy alone or in combination with dorsal decompression were reviewed. Degree of dysfunction was assessed separately for each pelvic limb; dogs with unilateral signs were included in group A, those with bilateral signs in group B. Retrieved data were: signalment, history, neurologic status on admission, 3 days, 6 weeks, and 6 months postoperatively, duration of clinical signs, results of MRI, surgical site(s), intraoperative findings, and outcome.
Results— Based on the clinical and MRI findings unilateral foraminotomy was performed in 8 dogs, bilateral foraminotomy in 1 dog, unilateral foraminotomy with concurrent dorsal decompression in 7 dogs, and bilateral foraminotomy with concomitant dorsal decompression in 4 dogs. Surgery confirmed the presence of foraminal stenosis in all dogs, with osteophyte formation and soft tissue proliferations being the most common lesions. Outcome was good to excellent in 19 dogs and poor in 1 dog. Mean follow-up was 15.2 months (range, 6–42 months).
Conclusion— Lateral foraminotomy addresses compressive lesions within exit and middle zones of the lumbosacral foramen.
Clinical Relevance— Successful surgical management of DLSS is dependent on recognition and correction of each of the compressive lesions within the lumbosacral junction.     

Dorsal laminectomy for caudal cervical spondylomyelopathy: postoperative recovery and long-term follow-up in 20 dogs

OBJECTIVE: To evaluate the postoperative morbidity and long-term outcome of dogs after dorsal laminectomy for caudal cervical spondylomyelopathy (CCSM). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Twenty dogs with CCSM. METHODS: Medical records of dogs treated by dorsal laminectomy for CCSM at North Carolina State University and Colorado State University between 1989 and 1999 were reviewed. Information on signalment, onset, progression and duration of clinical signs, diagnostic testing, sites of dorsal laminectomy, postoperative complications, length of hospitalization, and the ambulatory status on discharge was recorded. A minimum follow-up of 7 months was required for inclusion in the study. Neurologic status was graded (0 to 5) preoperatively, 2 days after surgery, and at the time of the study (final score). Improvement or worsening of the neurologic status was assessed by comparison of different scores for each dog. Additional follow-up information was obtained by means of a detailed telephone questionnaire directed at both the owner and referring veterinarian. RESULTS: Mean duration of clinical signs before surgery was 4.9 months. At admission, 15 dogs were ambulatory and 5 were nonambulatory. Neurologic status worsened in 70% of dogs 2 days after surgery but improved in all but 1 dog over the long term. Mean time to optimal recovery was 3.6 months. Long-term follow-up ranged from 7 months to 9 years (mean +/- SD, 3.2 +/- 2.4 years). Four dogs had confirmed recurrence; 2 other dogs may have had recurrence. CONCLUSIONS: Dorsal cervical laminectomy is an effective treatment for CCSM in those dogs with dorsal compression or multiple sites of involvement. CLINICAL RELEVANCE: Although most dogs' neurologic status transiently worsened after surgery, long-term outcome and recurrence rates were comparable to those seen with other surgical techniques for CCSM.     

Long-term functional outcome of dogs with severe injuries of the thoracolumbar spinal cord: 87 cases (1996-2001)

OBJECTIVE: To determine long-term (> 6 months) outcome of dogs with paraplegia and loss of hind limb deep pain perception (DPP) resulting from intervertebral disk herniation or trauma. DESIGN: Retrospective study. ANIMALS: 87 dogs. PROCEDURE: Outcome was determined as successful or unsuccessful. The association of neuroanatomic localization, breed, age, weight, sex, and (for dogs with intervertebral disk herniation) speed of onset of signs and duration of paraplegia prior to surgery with outcome was evaluated. Owners were contacted by telephone to identify long-term health problems. RESULTS: Nine of 17 dogs with traumatic injuries were treated, and 2 regained the ability to walk; none of the 17 dogs regained DPP. Sixty-four of 70 dogs with intervertebral disk herniation underwent surgery; 9 (14%) were euthanatized within 3 weeks after surgery (7 because of ascending myelomalacia), 37 (58%) regained DPP and the ability to walk, 7 (11%) regained the ability to walk without regaining DPP, and 11 (17%) remained paraplegic without DPP. Outcome was not associated with any of the factors evaluated, but speed of recovery of ambulation was significantly associated with body weight and age. Fifteen (41%) and 12 (32%) dogs that regained DPP had intermittent fecal and urinary incontinence, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the prognosis for paraplegic dogs without DPP because of trauma was guarded, while dogs with disk herniation had a better chance of recovering motor function. A third of the dogs that recovered motor function had intermittent incontinence. Persistent loss of DPP did not preclude recovery of motor function, but such dogs remained incontinent.     

A follow-up study of neurologic and radiographic findings in working German Shepherd Dogs with and without degenerative lumbosacral stenosis

OBJECTIVE: To identify radiographic abnormalities associated with degenerative lumbosacral stenosis (DLSS) in German Shepherd Dogs (GSDs) and determine whether specific radiographic abnormalities could be used to identify dogs at risk of developing DLSS. DESIGN: Cohort study. ANIMALS: 33 GSDs working as police dogs. PROCEDURES: Results of physical, neurologic, and orthopedic examinations were used to identify dogs with DLSS. Survey radiography of the lumbosacral junction was performed, and radiographs were compared with radiographs obtained 3 years earlier. RESULTS: DLSS was diagnosed in 15 of the 33 (45%) dogs. Thirteen of the 15 dogs with DLSS and 14 of the 18 dogs without DLSS had radiographic abnormalities of the lumbosacral junction. Twenty-two (67%) dogs were able to perform unrestricted duties, including 3 dogs with suspected DLSS. Six (18%) dogs had been excluded from active duty during the period of surveillance because of DLSS. Significant progression in specific clinical and radiographic signs was detected, but multiple logistic regression analysis did not identify any radiographic signs that could be used to predict the development of DLSS. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that survey radiography cannot be used to predict development of DLSS in working GSDs.     

Urinary Incontinence after Prostatectomy in Dogs

Eleven dogs with prostatic disease were treated by total prostatectomy. Urinary incontinence persisted in three of nine dogs, two of which were also incontinent before surgery. The incidence of postoperative incontinence may be reduced by undermining the prostatic capsule to preserve as much prostatic urethra as possible. The risk of postoperative incontinence appeared greater if there was prostatic neoplasia or preoperative urinary incontinence.     

Fecal incontinence and spinal cord abnormalities in seven dogs

Seven dogs with fecal incontinence and abnormal gaits were evaluated. Fecal incontinence was characterized as defecation of normal stools without posturing. Duration of clinical signs prior to evaluation ranged from 5 months to 3 years. Five dogs had upper motor neuron (UMN) paraparesis, and 2 dogs had UMN tetraparesis. With magnetic resonance imaging, spinal cord abnormalities primarily involving the dorsal aspect of the spinal cord were identified in all dogs. Five dogs had focal abnormalities, and 2 dogs had diffuse abnormalities of the spinal cord. Of the dogs with focal spinal cord lesions, 4 had cystic spinal cord abnormalities and 1 had a meningioma. Surgery was performed on all dogs with focal lesions; 4 of the 5 dogs had resolution of fecal incontinence after surgery. Results in these dogs suggest that fecal incontinence can be associated with spinal cord abnormalities and, depending on the characteristics of the lesion, can resolve after surgical treatment of the abnormality.     

Synovial cysts associated with cauda equina syndrome in two dogs

OBJECTIVE: To report synovial cysts associated with cauda equina syndrome in 2 dogs. STUDY DESIGN: Clinical cases. ANIMALS: Two German Shepherd dogs. METHODS: After magnetic resonance imaging detection, cysts were surgically removed via dorsal laminectomy. RESULTS: Six and 8 months after surgery, both dogs were free of clinical signs and no pain was elicited on lumbosacral joint manipulation. CONCLUSION: Although described in dogs, cysts at the lumbosacral joint might cause compression of the cauda equina nerve roots. Radical excision of the cyst capsule can result in resolution of clinical signs. CLINICAL RELEVANCE: Synovial cysts should be considered in the differential diagnosis of dogs with cauda equina compression syndrome when lumbosacral degenerative joint disease is present.     

Use of cystoscopic-guided laser ablation for treatment of intramural ureteral ectopia in male dogs: four cases (2006-2007)

OBJECTIVE: To describe and evaluate the outcome of cystoscopic-guided laser ablation of intramural ureteral ectopia in male dogs. DESIGN: Retrospective case series. ANIMALS: 4 incontinent male dogs with intramural ureteral ectopia. PROCEDURES: Intramural ectopic ureters were diagnosed via preoperative computed tomography-IV urography and subsequent cystoscopy. Transurethral cystoscopic-guided laser ablation (diode laser [n = 3 dogs] and holmium:yttrium aluminum garnet laser [1]) was performed to proximally relocate the ectopic ureteral orifice to the urinary bladder. Fluoroscopy was used during the procedures to confirm that the ureteral tract was intramural and the ureteral orifice was intravesicular after the procedure. In 1 dog with bilateral ureteral ectopia, staged laser ablation was performed at 6-week intervals because of difficulty viewing the second ureter on the first attempt. All ureteral orifices were initially located in the middle to proximal portion of the prostatic portion of the urethra. Six weeks after surgery, imaging was repeated in 3 of 4 dogs. RESULTS: Postoperative dysuria or hematuria did not develop. All dogs were immediately continent after laser treatment and remained so at a median follow-up period of 18 months (range, 15 to 20 months) without medical management. Conclusions and CLINICAL RELEVANCE: Ureteral ectopia can cause urinary incontinence in male dogs and is usually associated with other urinary tract abnormalities. Cystoscopic-guided laser ablation provided an effective and minimally invasive alternative to surgical management of intramural ureteral ectopia.     

Cauda equina compression syndrome (CECS): retrospective study of surgical treatment with partial dorsal laminectomy in 86 dogs with lumbosacral stenosis

We report our results of partial lumbosacral laminectomy for treatment of canine Cauda equina Compression Syndrome due to a lumbosacral stenosis. Opposite to conventional techniques of dorsal laminectomy, only widening of the Spatium interarcuale is performed. This is achieved by exstirpation of the Lig. flavum and partial dorsal laminectomy of the first sacral segment. The Proc. spinosi and integrity of facet joints are fully maintained by this technique. In 96.5% of 86 dogs treated with this method relief of dorsal pressure and permanent rapid regression of clinical symptoms was achieved. In two cases recurrence of clinical symptoms was observed during follow up and one case showed no improvement at all. In conclusion partial dorsal laminectomy is a minimal invasive technique for treatment of Cauda equina compression syndrome expressed by pain reaction accompanied by minor neurological deficits caused by lumbosacral stenosis. Maintained spinal stability allows short reconvalescence and the unrestricted use of dogs immediately post operation.     

Evaluation of colposuspension for treatment of incontinence in spayed female dogs

OBJECTIVE: To determine the long-term effects of colposuspension in spayed female dogs with urinary incontinence and identify preoperative anatomic or urodynamic measurements associated with a successful outcome. DESIGN: Prospective study. ANIMALS: 23 client-owned spayed female dogs with urinary incontinence. PROCEDURE: Prior to surgery, a history was obtained, and a physical examination, CBC, serum biochemical analyses, urinalysis, bacterial culture of a urine sample, vaginourethrocystography, urethral pressure profilometry, and leak point pressure test were performed. Colposuspension was performed, and preoperative tests were repeated 2 months after surgery. Clients were interviewed 2 weeks, 1 month, and 1 year after surgery. RESULTS: 22 dogs were followed up for 1 year. Twelve had complete urinary control 2 months after surgery, and 3 had complete urinary control 1 year after surgery. Dogs with normal urinary control at 2 months had an increased leak point pressure (LPP), compared with preoperative measurements, and their LPP was the same as normal dogs. Eight dogs had complete urinary control, and 9 were considered greatly improved 1 year after surgery when medical treatment was added to the effect of colposuspension. Client satisfaction was high, with 19 of 22 (86%) owners being pleased with their decision to have surgery performed. The only predictors of complete urinary control 2 months after surgery were a more caudal position of the external urethral opening in relation to the pubis on preoperative radiographs and a longer overall urethral length. CONCLUSIONS AND CLINICAL RELEVANCE: Colposuspension alone will result in complete urinary control in few dogs with urinary incontinence but may improve urinary control sufficiently that owners will be pleased. Preoperative vaginourethrocystography may be helpful in predicting response to surgery, and the LPP test correlates with improved urinary control.     

Magnetic Resonance Imaging in the Diagnosis of Degenerative Lumbosacral Stenosis in Four Dogs

Magnetic resonance imaging was used to diagnose degenerative lumbosacral stenosis in four dogs that had physical and neurologic signs consistent with a cauda equina lesion. Nerve root displacement by protruding disc material and loss of epidural fat were identified. In all dogs, the diagnosis was confirmed by dorsal laminectomy of the lumbosacral area.     

Lumbosacral intervertebral disk disease in six cats

Medical records of six cats diagnosed with lumbosacral intervertebral disk disease were reviewed. Clinical signs included reluctance to jump, low tail carriage, elimination outside the litter box, reluctance to ambulate, pelvic-limb paresis, urinary incontinence, and constipation. All cats had lumbosacral hyperpathia on palpation. Computed tomography in four cats revealed evidence of extradural spinal cord compression at the seventh lumbar (L(7)) to first sacral (S(1)) vertebral interspace. Compression was confirmed via myelography in three of these four cats, with confirmation in the fourth cat at the time of decompressive laminectomy. Each of the six cats underwent dorsal decompressive laminectomy at the L(7) to S(1) interspace. Postoperative clinical follow-up lasted 3 to 35 months, with most cats having excellent outcomes.     

Subtotal Intracapsular Prostatectomy Results in Normal Dogs

Subtotal intracapsular prostatectomy was performed on five normal dogs. All dogs were maintained for 60 days postoperatively. No urinary abnormalities were noted following surgery with the exception of transient urinary incontinence in one dog that lasted for 7 days. Upon termination of the study, the prostatic urethra had reepithelized in all dogs where a dorsal strip of epithelium was left in place during surgery.     

Comparison of two surgical techniques for management of intramural ureteral ectopia in dogs: 36 cases (1994-2004)

OBJECTIVE: To determine outcome associated with intramural ureteral ectopia treated with 1 of 2 surgical techniques (neoureterostomy with ligation of the distal ureteral segment vs neoureterostomy with resection of the distal ureteral segment) and compare results of these 2 techniques in dogs. DESIGN: Multicenter retrospective case series. ANIMALS: 36 dogs (15 treated with the ligation technique and 21 treated with the resection technique). PROCEDURES: Information was obtained from medical records. Long-term follow-up information was obtained by owner questionnaire. RESULTS: 15 of 21 (71%) dogs in the resection group and 7 of 14 (50%) dogs in the ligation group still had urinary incontinence after surgery. Three of 20 (15%) dogs in the resection group and 4 of 14 (29%) dogs in the ligation group reportedly had multiple episodes of urinary tract infection following surgery. The outcome of surgery was judged to be excellent by the owners of 10 of 18 (56%) dogs in the resection group and 9 of 14 (64%) dogs in the ligation group. No significant differences were found between surgery treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study suggest that although most owners of dogs that undergo surgery for treatment of intramural ureteral ectopia consider the outcome of surgery to be excellent, substantial proportions of dogs will continue to have urinary incontinence and recurrent urinary tract infections after surgery. Findings do not provide any support to the hypothesis that the resection technique is superior to the ligation technique for management of dogs with intramural ureteral ectopia.     

Asymmetrical, transitional, lumbosacral vertebral segments in six dogs: a characteristic spinal syndrome

Clinical findings in six dogs with asymmetrical, transitional, lumbosacral vertebral segments are reported. All dogs exhibited low back pain and varying degrees of asymmetrical cauda equina dysfunction. Results of myelography, epidurography, and magnetic resonance imaging (MRI) indicated a unilateral disk protrusion in all dogs. In the dogs with MRIs, focal degenerative alterations in the vertebral end plates and adjacent body of the vertebra were detected. All dogs were treated with a dorsal laminectomy or hemilaminectomy. Results following surgery were good or excellent in all six dogs.     

Association between postoperative outcome and results of magnetic resonance imaging and computed tomography in working dogs with degenerative lumbosacral stenosis

OBJECTIVE: To determine whether results of magnetic resonance imaging (MRI) and computed tomography (CT) are associated with postoperative outcome in working dogs with degenerative lumbosacral stenosis. DESIGN: Prospective cohort study. ANIMALS: 12 dogs treated surgically for degenerative lumbosacral stenosis. PROCEDURE: The lumbosacral vertebral column was examined before surgery by use of MRI and CT and after surgery by use of CT. Outcome, based on performance in standardized training exercises, was assessed 6 months after decompressive surgery. Associations between imaging results and postoperative outcome were determined by use of a Fisher exact test and logistic regression. RESULTS: None of the dogs were able to perform their duties before surgery. By 6 months after surgery, 8 of 12 dogs had been returned to full active duty. Nerve tissue compression was effectively localized by use of CT and MRI. Significant associations between results of imaging studies and postoperative outcome were not identified. CONCLUSIONS AND CLINICAL RELEVANCE: Surgical intervention is justified in high-performance working dogs with degenerative lumbosacral stenosis. However, results of imaging studies may be less important than clinical or surgical factors for predicting outcome in affected dogs.     

Evaluation of long-term effects of endoscopic injection of collagen into the urethral submucosa for treatment of urethral sphincter incompetence in female dogs: 40 cases (1993-2000)

OBJECTIVE: To evaluate long-term success of endoscopic injection of collagen into the urethral submucosa in female dogs with urinary incontinence caused by urethral sphincter incompetence. DESIGN: Retrospective study. ANIMALS: 40 incontinent female dogs. PROCEDURE: Medical records were reviewed for outcome and other results for dogs in which a cystoscope was passed into the urethra for deposition of 3 collagen deposits into the submucosa. RESULTS: 27 (68%) dogs were continent for 1 to 64 months (mean, 17 months) after the collagen injection. In another 10 dogs, incontinence improved and in 6 of these dogs, full continence was regained with administration of additional medication. In 3 dogs, incontinence was unchanged. As long as 12 months after injection, there was a deterioration in the initial result in 16 dogs, after which their condition stabilized. Mild and transient adverse effects developed in 6 (15%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Long-term success of endoscopic injection of collagen was satisfactory. Relapse of incontinence might be caused by flattening of the collagen deposits rather than resorption of the collagen.     

Biomechanical flexion-extension forces in normal canine lumbosacral cadaver specimens before and after dorsal laminectomy-discectomy and pedicle screw-rod fixation

Objective— To determine biomechanical flexion–extension forces in cadaveric canine lumbosacral specimens, before and after dorsal laminectomy with partial discectomy, and after dorsal pedicle screw–rod fixation of L7 and S1.
Study Design— Biomechanical cadaver study.
Animals— Cadaveric spine specimens without lumbosacral pathology from mature, intact Labrador retrievers (n=12).
Methods— Lumbosacral spine segments were subjected to a constant bending moment from L6 to S1 in a hydraulic 4-point bending materials testing machine. Force and displacement were recorded during each loading cycle constituting 1 complete flexion–extension cycle of the spine. Each spine segment had 3 series of recordings of 5 loading cycles each: (1) intact spine, (2) after surgical destabilization by dorsal laminectomy and partial discectomy, and (3) after surgical stabilization using dorsal pedicle screw–rod fixation.
Results— After dorsal laminectomy and partial discectomy, the neutral zone and range of motion were not different from those in the native spine specimen. After pedicle screw–rod fixation, the neutral zone and range of motion of the instrumented specimen significantly ( P <.0001) decreased compared with the native specimen and the specimen after dorsal laminectomy.
Conclusion— Dorsal laminectomy and partial discectomy does not lead to significant spinal instability in flexion and extension whereas pedicle screw and rod fixation effectively stabilizes the lumbosacral spine.
Clinical Relevance— Dorsal laminectomy and partial discectomy does not lead to significant spinal instability. Pedicle screw–rod fixation of L7 and S1 may be used to stabilize an unstable L7–S1 junction in dogs with degenerative lumbosacral stenosis.