Hemilaminectomy and vertebral stabilisation for the treatment of thoracolumbar disc protrusion in 28 dogs

Objectives : To evaluate the results of hemilaminectomy and vertebral stabilisation (+/? annulectomy) for the treatment of thoracolumbar disc protrusion. Methods : The medical records of dogs with thoracolumbar annular protrusions treated by hemilaminectomy and vertebral stabilisation were reviewed. Neurological function was assessed 24 hours following surgery. Long‐term follow‐up was by clinical examination or telephone questionnaire. Results : Twenty‐eight dogs fulfilled the criteria. Age ranged from 4 to 12·5 years (median 8 years, mean 7·7 years), bodyweight from 5·1 to 51·5 kg (median 28 kg, mean 27·1 kg), and duration of neurological signs before presentation from 48 hours to 104 weeks (median 5 weeks, mean 9·3 weeks). At presentation 22 dogs were ambulatory and six were non‐ambulatory. Myelography and/or magnetic resonance imaging (MRI) identified 31 thoracolumbar protrusions causing spinal cord compression. Unilateral hemilaminectomy was performed in 27 dogs and bilateral hemilaminectomy in one dog. Partial annulectomy was performed in 24 of 31 protrusions. Stabilisation was performed using vertebral body bone plates in 26 dogs and vertebral body screws and bone cement in two dogs. Internal vertebral venous plexus haemorrhage was recorded in nine dogs. A screw was inadvertently placed into an intervertebral disc in two dogs. Neurological examination 24 hours postoperatively revealed deterioration in pelvic limb motor function in 17 dogs. One dog was euthanatised at the owner’s request 6 days after surgery. Long‐term evaluation of 24 cases was performed 3 to 52 months following surgery (median 21 months, mean 23·9 months). Six dogs had improved from their preoperative status and one had deteriorated as assessed by the authors. Fifteen dogs had improved from their preoperative status and two were unchanged as assessed by owners. Clinical Significance : Hemilaminectomy and vertebral stabilisation are an effective treatment for chronic spinal cord compression due to thoracolumbar annular protrusion in dogs. A temporary deterioration in neurological function is not uncommon following surgery. Internal vertebral plexus haemorrhage and inappropriate vertebral body screw placement are potential complications.     

Follow-up study of 100 cases with thoracolumbar disc protrusions treated by lateral fenestration

One hundred-and-seventeen dogs with thoracolumbar disc protrusions were treated by lateral fenestration over a five year period. The results obtained in 100 of these cases are presented. The overall success rate was 87 per cent but only 33 per cent of those with paraplegia and loss of conscious pain sensation regained the use of their hindlimbs.     

The lateral fenestration of canine thoracolumbar disc protrusions: a review of 30 cases

Thirty dogs with disc protrusions in the thoracolumbar region were treated by lateral fenestration of the last three thoracic and first three lumbar discs. The case details and results of treatment are presented.     

Vertebral stabilisation for cervical spondylopathy using a screw and washer technique

A transvertebral screw and interbody washer technique was used to stabilise the vertebrae and maintain the intervertebral space in 34 adult dobermann pinschers with cervical spondylopathy. The long term success of the procedure was 50 per cent. Pre-operatively three dogs were considered mildly ataxic, 16 moderately ataxic, 13 severely ataxic and two non-ambulatory. Thirty dogs had radiographic changes of calcified disc, vertebral malalignment or narrow intervertebral disc space and all dogs had myelographic abnormalities in the caudal cervical spine. Vertebral malalignment and narrow intervertebral space correlated closely with myelographic cord compression. However, compressive lesions were not identified in 11 cases on plain films. Follow-up was available on 30 dogs of which 25 showed neurological improvement. This was temporary in 10 cases which were destroyed two weeks to three years following surgery.     

Early recurrence of thoracolumbar intervertebral disc extrusion after surgical decompression: a report of three cases

Thoracolumbar disc extrusions were diagnosed in three chondrodystrophic dogs with paraparesis of up to three days duration. All cases were managed by hemilaminectomy and removal of extruded disc material. In one dog, fenestration of the herniated disc space was also performed. Initially neurological function improved or was unchanged, but from two to ten days postoperatively clinical signs of deterioration became apparent. In all the dogs, recurrence of disc extrusion at the same location as the initial extrusion was diagnosed by computer tomography and at a second surgery abundant disc material was found at the hemilaminectomy site between the dura and an implanted graft of autogenous fat.     

Results of surgical treatment for thoracolumbar disc protrusion

Ninety-nine dogs were treated by hemilaminectomy for thoracolumbar intervertebral disc protrusion. Most animals were 4–7 years old and chondrodystrophoid. The incidence of protrusion was higher at the thoracolumbar junction. Animals with paresis, pain, or pain and paresis had a greater recovery rate than dogs with paralysis. Résumé. La protrusion du disque intervertébral thoracolombaire a été traitée par hémi-laminectomie chez 99 chiens, la plupart âgés de 4 à 7 ans et atteints de chondrodystrophie. Les protrusions étaient plus fréquentes à la jonction thoraco-lombaire. Les animaux qui manifes-taient de la parésie ou de la douleur, ou de la parésie et de la douleur, se rétablissaient plus vite et mieux que les animaux paralysés. Zusammenfassung. Neunundneunzig Hunde wurden mit Hemilaminektomie bei thoraco-lumbaren Zwischenwirbelscheibenvorfall behandelt. Die meisten Tiere waren 4–7 Jahre alt und chondrodystrophoid. Die Häufigkeit von Diskushernien war höher am thoracolumbarem Über-gangsabschnitt. Tiere mit Parese, Schmerzen oder Schmerzen und Parese wurden häufiger wiederhergestellt als Hunde mit Paralyse.     

Vertebral subluxation following ventral cervical decompression in the dog

Cervical intervertebral disk disease is commonly treated surgically by ventral decompression through a ventral slot. Nine dogs with documented vertebral subluxation following surgical creation of a ventral slot are reported. The location of the subluxation was at the fourth cervical (C4) to fifth cervical (C5) intervertebral space in two dogs, C5 to sixth cervical (C6) intervertebral space in four dogs, and C6 to seventh cervical (C7) intervertebral space in three dogs. The ventral slot width to vertebral body width ratio ranged from 0.39 to 0.80, with the ratio being 0.50 or greater in seven of eight cases evaluated radiographically. Surgical reduction and stabilization were performed in seven of nine dogs.     

Contrast-enhanced CT for localizing compressive thoracolumbar intervertebral disc extrusion

Thoracolumbar intervertebral disc extrusion is a common disease in dogs. Surgical decompression of the spinal cord is the preferred treatment. Localization of the compressive material is critical for surgical planning. Myelography has been used for localizing extruded disc material, but this procedure carries risk of complications. Computed tomography (CT) is becoming more available for use in veterinary medicine and CT myelography is used for localization of extruded disc material. This report compares CT with intravenous contrast medium and CT myelography for identifying extruded intervertebral discs. CT with intravenous contrast medium is as effective as CT myelography for determining level and laterality of compressive disc extrusions.     

Surgical decompression in dogs with thoracolumbar intervertebral disc disease and loss of deep pain perception: A retrospective study of 46 cases

The case details and outcome after surgical decompression of 46 dogs with thoracolumbar intervertebral disc disease with loss of deep pain perception prior to surgery were reviewed. Nineteen dogs (41.3%) recovered with a median follow-up period of 12.5 months. Recovery was defined as an ambulatory paraparesis, or better, with urinary and fecal continence. There was a better outcome in dogs with loss of deep pain for less than 24 hours prior to surgery (19/41; 46.3% recovered) than in dogs without deep pain perception for more than 24 hours (0/5; 0% recovered). Dogs with deep pain perception present at two weeks postoperatively had significantly higher success rate (8/12; 66.7% recovered) than dogs without deep pain perception at this time period (1/10; 10.0% recovered). The return of deep pain perception by two weeks postoperatively can be a useful positive prognostic indicator.     

A comparison of conservative treatment and fenestration for thoracolumbar intervertebral disc disease in the dog

Many dogs will recover after a thoracolumbar disc protrusion whether they are treated conservatively or surgically. Two statistically similar groups of dogs submitted to the Department of Surgery, Royal Veterinary College (RVC) and to the Department of Surgery, University of Glasgow Veterinary School (UGVS) were reviewed. At the RVC an aggressive surgical policy was adopted and at the UGVS a conservative regime was followed. A comparison has been made between the two groups to evaluate the advantages of each regime. This comparison has provided the basis for a treatment protocol for cases of thoracolumbar intervertebral disc disease in the dog.     

Comparison of hemilaminectomy and dorsal laminectomy for thoracolumbar intervertebral disc extrusion in dachshunds

Neurological improvement after decompressive surgery, without routine therapeutic or prophylactic disc fenestration, was evaluated retrospectively in a consecutive series of 93 dachshunds with thoracolumbar disc extrusion. In 24 per cent of procedures, deep pain sensation was not elicited in at least one hind paw before surgery. Median neurological status one to seven days after surgery, at the time of discharge, was significantly improved after hemilaminectomy compared with dorsal laminectomy (P < 0·05). After hemilaminectomy, deep pain sensation was not elicited in one or both hind paws of 8 per cent of dogs in which pain sensation was elicited before surgery, compared with 21 per cent after dorsal laminectomy (P > 0·05). Improvement in neurological grade at follow-up examination two to 12 weeks after hemilaminectomy was not significantly different compared with dorsal laminectomy (P > 0·05). Of dogs which were unable to walk before surgery, 83 per cent regained the ability to walk after hemilaminectomy, compared with 74 per cent after dorsal laminectomy (P > 0·05). In both groups, 50 per cent of dogs in which deep pain sensation was abnormal before surgery eventually regained the ability to walk after surgery (P = 1). One to two years after the first operation, a second laminectomy was performed in only 5 per cent of dogs because of extrusion of a different intervertebral disc which had not been fenestrated.     

The surgical treatment of cervical disc protrusions in the dog: a review of 40 cases

The case histories of 40 dogs with cervical disc protrusions are described. In each case fenestration of the affected disc and prophylactic fenestration of the other cervical discs was carried out. The results of treatment are presented.