A modified ventral fixation for surgical management of atlantoaxial subluxation in 19 dogs

OBJECTIVE: To describe a modified ventral stabilization technique for surgical management of atlantoaxial subluxation in dogs and to evaluate the outcome. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Nineteen client-owned dogs. METHODS: Medical records of 19 dogs with a radiographic diagnosis of atlantoaxial subluxation surgically managed by a modified ventral fixation technique (cortical screws, Kirschner wires, polymethylmethacrylate) were reviewed. Data on pre- and post-operative neurologic status, surgical technique, and complications were retrieved. Follow-up evaluation was performed at approximately 1 month. Telephone interview of the owner was used for long-term assessment (median follow-up for 17 surviving dogs was 10.5 months). RESULTS: Adequate reduction and stabilization was achieved in all dogs based on radiographic assessment immediately after surgery. Improved neurologic outcome occurred in 16 dogs at 1 month and in 15 dogs at follow-up; 2 dogs died of post-operative complications within 24 hours of surgery. One dog was euthanatized at the owners' request because of recurrent neck pain associated with implant failure after 1 month. Two dogs required surgery to remove broken and migrated implants, but further stabilization was not necessary. CONCLUSIONS: Adequate stabilization and improved neurologic outcome was achieved in most dogs. However, on account of the small size of the study and the variable neurologic signs of the dogs on admission, the surgical technique described could not be compared to those previously reported. CLINICAL RELEVANCE: The surgical technique described is an effective means of surgical treatment for atlantoaxial subluxation.     

Application of Ventral Pins and Polymethylmethacrylate for the Management of Atlantoaxial Instability: Results in Nine Dogs

Objective — The purpose of this report was to determine the efficacy of the application of ventral pins and polymethylmethacrylate for the management of congenital and traumatic atlantoaxial instability (AAI) in dogs.
Study Design — Medical records and radiographs of nine dogs with AAI were reviewed for neurological deficits, clinical diagnosis, surgical technique, and long-term outcome.
Sample Population — Six toy breed dogs with congenital AAI and three medium or large breed dogs with traumatic AAI were identified for inclusion in the study.
Methods — The atlantoaxial joints of nine dogs with AAI were surgically stabilized using ventral application of pins and polymethylmethacrylate. Follow-up evaluation for resolution of clinical signs and possible complications of surgery was performed in all dogs. The median follow-up time for surviving dogs (8) was 11.5 months with a mean of 13 months.
Results — An excellent outcome was identified in five patients. Three dogs had a good outcome and one dog died of respiratory complications. Cervical pain was eliminated or significantly reduced in all dogs that survived and none of the dogs had major residual neurological deficits.
Conclusions — Arthrodesis could not be confirmed on follow-up radiographs due to the presence of the polymethylmethacrylate; however, adequate stabilization of C1-C2 appears to have been achieved based on the resolution of clinical signs.
Clinical Relevance — Application of ventral pins and polymethylmethacrylate is an effective means of surgical treatment for congenital and traumatic AAI.     

Atlantoaxial Instability: A Ventral Surgical Technique for Decompression, Fixation, and Fusion

Atlantoaxial stability was evaluated in 12 surgically stabilized dogs and 6 control dogs after odontoidectomy and dorsal atlantoaxial ligament separation. The atlantoaxial instabilities were stabilized with transarticular pins from a ventral approach. Cancellous bone grafts harvested from the proximal humerus were used to promote joint fusion. Good joint stability, alignment, and early fusion were documented clinically, radiographically, and histopathologically in stabilized dogs. Because of our consistent results despite variable pin angles, we recommend this technique for use in dogs with atlantoaxial instability requiring surgical stabilization.     

Stabilisation of atlantoaxial subluxation in the dog through ventral arthrodesis

Ten miniature breed dogs with atlantoaxial subluxation underwent ventral lag screw stabilisation. The procedure did not include bone graft packing into the atlantoaxial articulation. Four dogs showed continuous improvement after surgery. Three dogs developed complications due to external trauma and postoperative implant failure but improved with conservative therapy. Three patients died or were euthanized in early perioperative or postoperative period. The long-term outcome was good or favourable in all surviving patients. Suspected fibrous tissue proliferation and stabilisation without permanent bone fusion was found to be clinically satisfactory when the atlantoaxial joint has been subjected to limited stress during a long-term monitoring period.     

Open versus closed bilateral anal sacculectomy for treatment of non-neoplastic anal sac disease in dogs: 95 cases (1969-1994)

OBJECTIVE: To determine complications associated with anal sacculectomy in dogs with non-neoplastic anal sac disease and compare complication rates for open versus closed techniques. DESIGN: Retrospective study. ANIMALS: 95 dogs. PROCEDURE: Medical records were reviewed for information on signalment, history, physical examination findings, type of anal sac disease, surgical technique (closed, standard open [surgery performed prior to 19801, or modified open [surgery performed after 19801), and postoperative complications. RESULTS: In 57 dogs, a closed technique was used, and in 38, an open technique was used. Only 3 dogs developed short-term complications (excessive drainage, scooting and inflammation, and seroma formation), and 14 developed long-term complications (continued licking of the surgery site, fecal incontinence, fistulation, and stricture formation). Development of postoperative complications was significantly associated with surgical technique. Dogs that underwent standard open sacculectomy prior to 1980 were 13.67 times as likely to have a long-term complication as were dogs that underwent closed sacculectomy. Weight of the dog, type of anal sac disease, age at the time of surgery, and whether the wound was closed surgically were not significantly associated with whether dogs developed postoperative complications. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that anal sacculectomy is a safe and effective treatment for non-neoplastic anal sac disease in dogs and is associated with a low rate of complications. The standard open technique was associated with the greatest number of complications, whereas complication rates for the closed and modified open techniques were similar to each other.     

Use of the Kishigami Atlantoaxial Tension Band in Eight Toy Breed Dogs with Atlantoaxial Subluxation

Objective— To determine the applicability, complications, and long-term functional outcome of the Kishigami Atlantoaxial Tension Band (Kishigami AATB) for management of congenital and traumatic atlantoaxial (AA) instability in toy breed dogs.
Study Design— Case series.
Animals— Toy breed dogs (n=8) with congenital or traumatic AA instability.
Methods— The AA joint of each dog was surgically stabilized through a dorsal approach using the original or a modified version of the Kishigami AATB. Pre- and postoperative neurologic status, radiographs, and complications were reviewed. Follow-up examination was performed at 1 and 12 months.
Results— Functional improvement occurred in 5 dogs; 1 dog did not improve or worsen and 2 dogs were euthanatized at owner request. Adequate reduction and stabilization was achieved in 7 dogs based on immediate postoperative radiographs; failure of reduction was evident in 1 dog. No relevant complications occurred.
Conclusions— Kishigami AATB may be acceptable as an alternative method for dorsal stabilization of AA subluxation in toy breed dogs in which use of ventral screws or pins is challenging. Experience with this technique in a larger population is necessary to compare our results to those reported by ventral approach.
Clinical Relevance— The surgical technique described is effective, safe, and simple in the surgical treatment of AA subluxation in toy breed dogs.     

Risk factors affecting the outcome of surgery for atlantoaxial subluxation in dogs: 46 cases (1978-1998)

OBJECTIVE: To identify risk factors for successful surgical management of dogs with atlantoaxial subluxation (AAS). DESIGN: Retrospective study. ANIMALS: 46 dogs managed surgically for AAS. PROCEDURE: Age at onset of clinical abnormalities, duration of clinical abnormalities prior to surgery, radiographic appearance of the dens, type (dorsal or ventral procedure) and number (1 or 2) of surgeries performed, grade of postoperative atlantoaxial joint reduction, and neurologic status prior to surgery (preoperative), when dogs were discharged from the hospital (postoperative), and during a follow-up evaluation (final) were obtained from the dogs' medical records. Risk factors for surgical success and degree of neurologic improvement were identified and analyzed for predictive potential. RESULTS: Age at onset of clinical abnormalities < or = 24 months was significantly associated with greater odds of a successful first surgery and final outcome and a lower postoperative neurologic grade. Duration of clinical abnormalities < or = 10 months was significantly associated with greater odds of a successful final outcome and a lower final neurologic grade. A preoperative neurologic grade of 1 or 2 was significantly associated with a lower final neurologic grade. Potential risk factors that did not affect odds of a successful outcome included type of surgery performed, grade of atlantoaxial joint reduction, radiographic appearance of the dens, or need for a second surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Age at onset of clinical abnormalities, duration of clinical abnormalities prior to surgery, and preoperative neurologic status are risk factors for success of surgical management of AAS in dogs.     

Radiographic morphology of the cranial portion of the cervical vertebral column in Cavalier King Charles Spaniels and its relationship to syringomyelia

OBJECTIVE: To compare radiographic morphology of the atlantoaxial region between Cavalier King Charles Spaniels (CKCSs) and dogs of other breeds and determine whether there was an association between radiographic morphology of the atlantoaxial region and syringomyelia in CKCSs. ANIMALS: 65 CKCSs and 72 dogs of other breeds. PROCEDURES: The amount that the spinous process of the axis overlapped the dorsal arch of the atlas, the relative size of the spinous process of the axis, and the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position were measured on lateral radiographic projections of the atlantoaxial region. Magnetic resonance images were reviewed to identify CKCSs with syringomyelia. RESULTS: The amount of overlap of the atlas and axis and the relative size of the spinous process of the axis were significantly smaller in CKCSs than in dogs of other breeds. However, the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position was not significantly different between groups, and no association was detected between syringomyelia and excessive atlantoaxial joint space widening or between syringomyelia and an excessively small axial spinous process. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that radiographic morphology of the atlantoaxial region in CKCSs differs from morphology of that region in dogs of other breeds, but that these differences do not account for why some CKCSs develop syringomyelia and others do not.     

Ventral approach for stabilization of atlantoaxial subluxation secondary to odontoid fracture in a foal

Atlantoaxial subluxation secondary to odontoid fracture in a 30-day-old foal was corrected by alignment of the atlantoaxial joint and stabilization with 2 ventrally placed dynamic compression plates. At 90 days after surgery, healing of the fracture, with adequate alignment of the atlantoaxial joint, was confirmed radiographically. The foal was only slightly tetraparetic at that time. At 1 year after surgery, the gait was normal. It was concluded that the technique has advantages over the use of Steinmann's pins or external coaptation for stabilization. The ventral approach allows decompression, anatomic alignment, and immediate stabilization of the subluxation. Potential complications of the ventral approach include laryngeal paralysis.     

Ventral abdominal, transdiaphragmatic approach for implantation of cardiac pacemakers in the dog

Surgical implantation of a sutureless myocardial electrode and pulse generator was performed in 18 dogs, using a ventral abdominal, transdiaphragmatic approach. Twelve dogs were greater than or equal to 10 years old. The 18 dogs weighed from 3 to 54 kg. Indications for permanent cardiac pacemaker implantation included complete (3rd degree) atrioventricular block, sick sinus syndrome, and sinus bradycardia. Few complications developed during or after surgery. One dog died during surgery from ventricular fibrillation, and hypertrophic cardiomyopathy was found at necropsy. Five dogs died 1 to 19 months after surgery (mean, 8.6 months) because of renal failure, hepatic cirrhosis, congestive cardiomyopathy, or idiopathic causes. Twelve dogs were alive 1 to 48 months after surgery (mean, 15.1 months). The surgical approach was used a second time in 3 dogs to replace the myocardial electrode wire and pulse generator 4, 16, and 26 months after surgery; technical complications were not associated with the second surgery in these 3 dogs. In 2 dogs that had initial pacemaker implantation via lateral thoracotomy, a transdiaphragmatic approach was used to replace the myocardial electrode lead and pulse generator 25.5 and 26 months after surgery. According to results of this study, the ventral abdominal, transdiaphragmatic approach for permanent pacemaker implantation in the dog is a simpler technique, with decreased surgery time, decreased time of tissue exposure, and decreased rate of infection, as compared with results described by investigators who used lateral thoracotomy or midline celiotomy and caudal one-third median sternotomy.     

Unilateral arytenoid lateralisation: An assessment of technique and long term results in 62 dogs with laryngeal paralysis

Sixty-two dogs with laryngeal paralysis were presented over a three year period. Presenting clinical signs included inspiratory stridor (100 per cent), exercise intolerance or syncopal episodes (81 per cent), loss or alteration in phonation (48 per cent) and coughing or gagging when eating (29 per cent). Causes of the paralysis were determined as traumatic (two dogs), neoplastic (two dogs), iatrogenic (two dogs), congenital (one dog) and idiopathic (55 dogs). Unilateral arytenoid lateralisation was performed in all dogs. The perioperative complication rate was approximately 10 per cent, while the success rate as judged by owners one year postoperatively was greater than 90 per cent. The technique avoided many of the recorded complications of intralaryngeal surgery. Operative times were short and the requirement for postoperative monitoring was minimal. Increasing familiarity with the technique favourably influenced the incidence of complications and the success rate.     

Use of the cumulative summation technique to quantitatively assess a surgical learning curve: canine total hip replacement

Objective: To quantitatively assess a surgical “learning curve” using the cumulative summation (CUSUM) score technique. Study Design: Application of a CUSUM technique to a consecutive series of surgical cases. Animals: Consecutive primary cemented total hip replacement (THR; n=116) in 106 dogs. Methods: Records of all dogs that had primary canine THR were reviewed. Data retrieved included date of surgery, postoperative complications, and duration of follow‐up. The 12‐week outcome was analyzed graphically and with a CUSUM technique. Results: One hundred and one (87%) procedures were “successful” and 15 (13%) developed major complications within 12 weeks (failures). The CUSUM chart clearly demonstrated an initial “learning curve” of ～44 THR. Conclusion: The CUSUM technique can be used to demonstrate the learning curve for canine THR surgery.     

Partial Gastrectomy with an Automatic Stapling Instrument for Treatment of Gastric Necrosis Secondary to Gastric Dilatation-Volvulus

A gastrointestinal anastomosis stapling instrument was used to perform partial gastrectomy in nine dogs undergoing emergency surgery for gastric dilatation-volvulus. The amount of necrotic stomach resected was 20% to 50%. Permanent gastropexy was performed, and six dogs also required partial or total splenectomy. Six dogs (67%) were normal after surgery, with follow-up periods of 6 to 16 months for five dogs. One dog died and two dogs were euthanatized because of postoperative complications unrelated to the surgical technique. There were no complications involving the partial gastrectomy staple line.     

COMPUTED TOMOGRAPHY VARIATIONS IN MORPHOLOGY OF THE CANINE ATLAS IN DOGS WITH AND WITHOUT ATLANTOAXIAL SUBLUXATION

Computed tomography images of 120 dogs were reviewed to characterize variations in atlas morphology, and to identify breed‐specific morphologic features. The neural arch of the atlas was thicker in large dogs and male dogs than in small dogs, having a layer of trabecular bone between the inner and outer layers of compact bone. The transverse processes of the atlas were relatively longer in large dogs than in small dogs. Twelve (10%) dogs had incomplete ossification of the atlas. Incomplete ossification of the atlas was associated with gun dogs. Eight dogs had atlantoaxial subluxation. All eight dogs with atlantoaxial subluxation had cervical signs, whereas none of the seven dogs with incomplete ossification of the atlas unaccompanied by atlantoaxial subluxation had clinical signs referable to that area. Of five dogs with both atlantoaxial subluxation and incomplete ossification of the atlas, four had osseous defects affecting both the intercentrum and neural arch, and one had only an osseous defect affecting the neural arch. There was a strong association between incomplete ossification of the atlas and atlantoaxial subluxation (odds ratio 35.0, 95% CI 7.0–175, P=0.00002), which supports the hypothesis that incomplete ossification of the atlas predisposes dogs to atlantoaxial subluxation.     

Complications of enteroplication for the prevention of intussusception recurrence in dogs: 35 cases (1989-1999).

OBJECTIVE: To compare complication and recurrence rates in dogs treated for intussusception that underwent enteroplication to rates in dogs treated for intussusception that did not undergo enteroplication. DESIGN: Retrospective study. ANIMALS: 35 dogs with intestinal intussusception. PROCEDURE: Information on signalment, clinical signs, potential predisposing causes, surgical technique, opioid administration, use of enteroplication, postoperative complications, and whether the intussusception recurred was obtained from the medical records. RESULTS: Dogs ranged from 8 weeks to 10 years old. Opioids were administered in the perioperative period in 34 dogs. Enteroplication was performed in 16 dogs. Complications of enteroplication that required a second surgery were identified in 3 dogs. None of the 16 dogs that underwent enteroplication had a recurrence of intussusception, whereas 1 of the 19 dogs that did not undergo enteroplication had a recurrence. Rate of intussusception recurrence and likelihood that a second surgical procedure would be required were not significantly different between dogs that underwent enteroplication and dogs that did not. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that enteroplication may be associated with life-threatening complications in dogs, but the likelihood of a dog requiring a second surgical procedure following surgical correction of intussusception was not different between dogs that underwent enteroplication at the time of the initial surgery and dogs that did not.     

The Effect of Laparoscopic Versus Open Ovariectomy on Postsurgical Activity in Small Dogs

Objective— To describe a technique for laparoscopic ovariectomy (LapOVE) in small dogs, and compare the surgical time, complications, and postoperative activity of dogs undergoing LapOVE to those undergoing conventional traditional open ovariectomy (OOVE).
Study Design— A randomized, controlled clinical trial.
Animals— Intact small breed (<10 kg) female dogs (n=20).
Methods— Ventral median celiotomy was performed for OOVE. A 2-midline portal technique using a 3.5 mm laparoscope port and a 6 mm instrument portal was used for LapOVE. An accelerometer was attached to the collar of each dog to record 24-hour preoperative and 48-hour postoperative activity. Total activity counts recorded before surgery were compared with total counts recorded after surgery. The percent change in counts after surgery was compared between OOVE- and LapOVE-treated dogs.
Results— No major complications occurred and surgical time for LapOVE was significantly longer than for OOVE cases ( P =.005). Dogs in the LapOVE group had a 25% decrease in total activity counts after surgery (95% confidence interval [CI]: 11–38%), whereas dogs in the OOVE group had a 62% decrease in total activity counts after surgery (95% CI: 48–76%).
Conclusions— Both procedures were performed with reasonable surgical times and without major complication. Postoperative activity, as measured by accelerometry, was significantly different between the 2 groups.
Clinical Relevance— Laparoscopy is a safe method for ovariectomy in small dogs and results in increased postoperative activity counts when compared with an open technique.     

Longitudinal bone transport for treatment of primary bone tumors in dogs: technique description and outcome in 9 dogs

OBJECTIVE: To describe a surgical technique for bone transport osteogenesis (BTO) limb salvage and report outcome in 9 dogs with primary bone tumors. ANIMALS: Nine dogs with spontaneously occurring primary bone tumors. RESULTS: BTO surgery was performed as a primary means of limb salvage in 7 dogs and as a salvage procedure after catastrophic allograft infection and failure in 2 dogs. Mean defect size was 9.5 cm with a mean of 123 days distraction until docking. Mean time from surgery to fixator removal was 205 days. Minimum follow-up was 9 months. There were 2 histologically confirmed local recurrences where although limb function was excellent, eventually resulted in limb amputation. Limb function was good to excellent in all but 2 dogs; 1 was chronically non-weight bearing before BTO surgery because of complications associated with an allograft limb salvage that had been performed previously on the same limb. The cause of lameness in the other dog was undetermined. CONCLUSIONS: BTO limb salvage can be successful in dogs with primary bone tumors. Whereas allograft limb salvage may be simpler from an initial management perspective, BTO has some unique advantages when compared with the allograft technique. CLINICAL RELEVANCE:BTO has an emerging role in limb salvage surgery for dogs with primary bone tumors. BTO provides excellent long-term outcomes in some dogs with primary bone tumors and will likely become increasingly more attractive as technique modifications allow the duration of the treatment to be shortened.     

A comparison of anesthetic complications between diabetic and nondiabetic dogs undergoing phacoemulsification cataract surgery: a retrospective study

Objective To compare the incidence of anesthetic complications in diabetic and nondiabetic dogs undergoing general anesthesia and phacoemulsification cataract surgery. Procedure The medical and anesthetic records of all dogs undergoing phacoemulsification cataract surgery at Davies Veterinary Specialists between 2005 and 2008 were reviewed. Anesthetic records were evaluated by an ECVAA Diplomate. Dogs for which records were incomplete were excluded. The anesthetic technique, including all drugs administered in the perioperative period, was recorded. The anesthetic complications investigated included hypotension (MAP (mmHg): ≥55 none/mild; ≤54 moderate/severe), bradycardia (<60 bpm associated with hypotension) and hypothermia (esophageal temperature <36.7 °C). Where hypotension was present, the method of and response to treatment was recorded. The incidence of severe hyperglycemia (blood glucose >13.75 mmol/L (250 mg/dL)) in the diabetic group was also assessed. Results 66 diabetic and 64 nondiabetic dogs were included in the study. Diabetic dogs were more likely to develop moderate and severe intraoperative hypotension than nondiabetic dogs. Forty‐four percent of diabetic dogs had at least one episode of severe hyperglycemia whilst anesthetized. Conclusions Diabetic dogs undergoing phacoemulsification are more likely to suffer the anesthetic complications of moderate and severe hypotension than nondiabetic dogs. The increased incidence and severity of hypotension in diabetic dogs may be explained by hypovolemia secondary to hyperglycemia and resultant osmotic diuresis.