Lateral ear canal resection and bulla osteotomy with marsupialization to treat otitis media in rabbits: forty-eight procedures.

OBJECTIVE: Describe lateral ear canal resection and bulla osteotomy with marsupialization (LECARBOM) in rabbits with otitis media (OM), and report outcomes, complications, bacteria cultured from middle ears, and their antimicrobial susceptibility testing (AST) results. STUDY DESIGN: Retrospective clinical case series; single referral hospital. ANIMALS: Forty-two rabbits with naturally occurring OM. METHODS: Medical records (2011-2021) of rabbits with CT-confirmed OM undergoing surgery were reviewed for outcomes, complications, bacteria cultured from middle ears, and AST. RESULTS: Surgery was performed on 48 ears, and outcomes determined 21 days postoperatively. All rabbits survived the procedure. Otitis externa resolved in all lop-eared rabbits. Of 29 ears with OM-associated head tilt, eight (28%) resolved, nine (31%) improved, seven (24%) remained unchanged and five (17%) worsened. Outcome was not associated with head tilt duration nor OM severity. Postoperative complications occurred in 12 (25%) cases, seven of which had wound margin dehiscence that healed by 21 days. The most frequent bacteria isolated were Pasteurella multocida (16%), Bordetella bronchiseptica (14%) and Staphylococcus aureus (14%). Bacteria were sensitive to azithromycin, marbofloxacin or enrofloxacin and resistant to penicillin. CONCLUSION: LECARBOM is a well-tolerated surgical procedure to treat OM. It also improved or stabilized 83% of cases with head tilt and resolved all cases with otitis externa. CLINICAL SIGNIFICANCE: LECARBOM with administration of an AST-sensitive antibiotic, or azithromycin when no AST is performed, should be effective in rabbits with OM. Postsurgically, it resolves or alleviates most secondary conditions such as otitis externa, head tilt and facial nerve paralysis.

Assessment of a vessel and tissue-sealing device for ovariectomy in chickens to evaluate the potential application of the procedure to other avian species.

OBJECTIVE: To assess the feasibility of a novel technique involving a vessel and tissue-sealing device (VTSD) for ovariectomy in chickens to evaluate the potential application of the procedure to other avian species. ANIMALS: 20 domestic laying hens (Gallus domesticus), of which 10 were immature (< 4 months old) and 10 were adults (> 18 months old). PROCEDURES: Ovariectomy was performed with a VTSD through a left lateral celiotomy. Birds were allowed to recover for 14 days after the procedure and then were euthanized for necropsy. A board-certified veterinary pathologist performed complete necropsies, with particular attention to identifying any remaining ovarian tissue. RESULTS: All birds survived the procedure. For the mature and juvenile birds, the mean ± SD durations of anesthesia (interval from intubation to extubation) were 67.2 ± 7.6 minutes and 50.5 ± 5.1 minutes, respectively, and mean durations of surgery were 45.3 ± 8.5 minutes and 31.6 ± 5.1 minutes, respectively. Three birds had severe hemorrhage during ovariectomy. At necropsy, ovarian tissue was present grossly in 2 mature birds and histologically in 6 additional birds (2 mature and 4 juvenile birds), indicating incomplete excision in 8 (40%) birds. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the evaluated VTSD can be used to successfully perform ovariectomies in both juvenile and mature chickens, although the procedure was associated with major hemorrhage and incomplete excision of ovarian tissue in some cases. Use of this VTSD for ovariectomy in birds of other species, particularly birds with reproductive tract disease, should be investigated.

Acute hyperkalemia as anesthetic complication in a diabetic dog undergoing tumor excision.

A mixed-breed dog with a history of diabetes mellitus underwent surgical removal of multiple colonic adenocarcinomas. The dog acutely developed electrocardiographic changes compatible with hyperkalemia during manipulation of the tumors, which was confirmed and treated. Although it was not possible to confirm clinical tumor lysis syndrome in this dog, the hyperkalemia and resultant arrhythmia that occurred during tumor manipulation were suggestive of acute tumor lysis syndrome. Key clinical message: Hyperkalemia is a serious anesthetic and intraoperative complication that should be considered in dogs undergoing solid tumor resection due to the potential risk of developing acute tumor lysis syndrome. Diabetic patients may also be at increased risk of developing hyperkalemia. Both the potassium concentration and ECG should be routinely monitored during these procedures.

Hyperkaliémie aiguë comme complication lors de l'anesthésie d'un chien diabétique subissant une excision tumorale. Un chien de race croisée avec une historique de diabète mellitus a subi une chirurgie pour retirer de multiples adénocarcinomes coloniques. Le chien développa de manière aiguë des changements électrocardiographiques compatibles avec une hyperkaliémie durant la manipulation des tumeurs, ce qui fut confirmé et traité. Bien qu'il ne soit pas possible de confirmer un syndrome clinique de lyse des tumeurs chez ce chien, l'hyperkaliémie et l'arythmie qui en résulta durant la manipulation des tumeurs étaient suggestives du syndrome aigu de lyse des tumeurs.Message clinique clé :L'hyperkaliémie est une complication sérieuse lors de l'anesthésie et de la chirurgie qui devrait être considérée chez les chiens subissant la résection d'une tumeur solide dû au risque potentiel de développer le syndrome aigu de lyse des tumeurs. Les patients diabétiques pourraient également présenter un risque plus grand de développer une hyperkaliémie. La concentration de potassium et l'ECG devraient être surveillés de routine durant ces procédures.(Traduit par Dr Serge Messier).

Efficacy of application of an alcohol-based antiseptic hand rub or a 2% chlorhexidine gluconate scrub for immediate reduction of the bacterial population on the skin of dogs.

OBJECTIVE To compare the efficacy of application of an alcohol-based antiseptic (80% ethyl alcohol) hand rub (ABAHR) with that of a 2% chlorhexidine gluconate scrub (CGS2) for immediate reduction of the bacterial population on the skin of dogs. ANIMALS 50 client-owned dogs with no evidence of skin disease. PROCEDURES On each dog, 2 areas of hair on the ventral aspect of the abdomen were clipped with a No. 40 blade and cleared of debris. A direct contact plate holding tryptic soy agar with polysorbate 80 and lecithin was gently pressed (for 2 seconds) on each skin site (preapplication sample). The CGS2 and ABAHR were each aseptically applied to 1 skin site on each dog. A direct contact plate was subsequently applied to each site in a similar manner (postapplication sample). All plates were cultured, and bacterial isolates were identified and quantified by the number of CFUs per plate. RESULTS Application of the CGS2 and ABAHR significantly decreased skin bacterial colony counts, compared with findings for preapplication samples. The number of CFUs per plate or postapplication percentage reduction in CFUs per plate did not differ between treatments. There were no adverse skin reactions associated with either application. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that applications of ABAHR and CGS2 were equally effective at immediately reducing the bacterial population on the skin of dogs, and there was no significant difference in percentage reduction in colony counts between the 2 applications.

Collateral circulation in ferrets (Mustela putorius) during temporary occlusion of the caudal vena cava.

OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes. ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females). PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later. RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O. CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

Elution of Clindamycin and Enrofloxacin From Calcium Sulfate Hemihydrate Beads In Vitro.

OBJECTIVE: To compare the in vitro elution characteristics of clindamycin and enrofloxacin from calcium sulfate hemihydrate beads containing a single antibiotic, both antibiotics, and each antibiotic incubated in the same eluent well. STUDY DESIGN: Experimental in vitro study. METHODS: Calcium sulfate hemihydrate beads were formed by mixing with clindamycin and/or enrofloxacin to create 4 study groups: (1) 160 mg clindamycin/10 beads; (2) 160 mg enrofloxacin/10 beads; (3) 160 mg clindamycin + 160 mg enrofloxacin/10 beads; and (4) 160 mg clindamycin/5 beads and 160 mg enrofloxacin/5 beads. Chains of beads were formed in triplicate and placed in 5 mL phosphate buffered saline (PBS; pH 7.4 and room temperature) with constant agitation. Antibiotic-conditioned PBS was sampled at 14 time points from 1 hour to 30 days. Clindamycin and enrofloxacin concentrations in PBS were determined using high-performance liquid chromatography. RESULTS: Eluent concentrations from clindamycin-impregnated beads failed to remain sufficiently above minimum inhibitory concentration (MIC) for common infecting bacteria over the study period. Enrofloxacin eluent concentrations remained sufficiently above MIC for common wound pathogens of dogs and cats and demonstrated an atypical biphasic release pattern. No significant differences in elution occurred as a result of copolymerization of the antibiotics into a single bead or from individual beads co-eluting in the same eluent well. CONCLUSION: Clindamycin-impregnated beads cannot be recommended for treatment of infection at the studied doses; however, use of enrofloxacin-impregnated beads may be justified when susceptible bacteria are cultured.

Penile amputation and scrotal urethrostomy followed by chemotherapy in a dog with penile hemangiosarcoma.

A 7 yr old castrated male standard poodle weighing 25 kg was presented with a 5 day history of hematuria, dysuria, and the presence of a 2.5 cm, firm swelling within the prepuce. Abdominal radiographs revealed a soft-tissue mass on the distal prepuce and lysis of the cranial margin of the os penis. The patient was sedated and an ulcerated hemorrhagic mass was identified at the tip of the penis. The mass was diagnosed as hemangiosarcoma via incisional biopsy. A penile amputation with scrotal urethrostomy was performed followed by chemotherapy with doxorubicin.

Knot security and tensile strength of suture materials.

OBJECTIVE: To evaluate knot security and tensile failure load of suture tied in simple interrupted, beginning continuous, and ending continuous patterns for 11 suture materials commonly used in small animal surgery. STUDY DESIGN: Mechanical study. METHODS: For each of 11 suture material types, and 5 knot sizes (2, 3, 4, 5, and 6 throws) 2 surgeons each tied 6 knots (n = 12 for each knot size in 11 suture materials). Three types of patterns were evaluated: a simple interrupted square knot, a square knot beginning a simple continuous pattern, and the knot ending a simple continuous pattern. All knots were incubated in healthy canine donor plasma at 40°C for a minimum of 24 hours. Sutures were evaluated for knot security (knots untied, suture failed by breaking, suture slipped from the clamps, or suture untied before testing) and maximum load carried before knot slippage or knot failure (termed tensile failure load). RESULTS: Significant differences were found in knot security and tensile failure load among suture types. There was no significant difference between the simple interrupted knots and the knots at the beginning of a simple continuous pattern; however, both were significantly less likely to fail than the knots tied at the end of a simple continuous pattern. The number of throws per knot had a significant effect for knot security and tensile failure load. Surgeon experience had a significant effect on failure mode and tensile failure load. CONCLUSIONS: Suture type, number of throws per knot (knot size), suture pattern, and surgeon experience play an important role in knot security and should be considered when performing surgery.

Effect of using triclosan-impregnated suture for incisional closure on surgical site infection and inflammation following tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To compare surgical site infection and inflammation rates between the use of nonimpregnated (polydioxanone and poliglecaprone 25) versus triclosan-impregnated (polydioxanone and poliglecaprone 25) suture for incisional closure in dogs undergoing a standardized orthopedic procedure (tibial plateau leveling osteotomy [TPLO]). DESIGN: Retrospective cohort study. ANIMALS: 283 dogs that underwent TPLO between November 2005 and December 2009. PROCEDURES: Medical records were reviewed for age; body weight; body condition score; use of propofol; perioperative and postoperative administration of antimicrobials; presence of a preoperative infection; use of a jig; technique of joint exploration; type of suture material (triclosan impregnated vs nonimpregnated) used to close the pes anserinus, subcutaneous layer, and subcuticular layer; use of staples or suture to close the skin; and surgery and anesthesia durations. The outcome variables were surgical site inflammation and infection. RESULTS: Rates of infection and inflammation did not differ between surgeries for which triclosan-impregnated suture was used (n = 159 [8.8%, and 18.8%, respectively]) and those for which nonimpregnated suture was used (112 [10.7% and 15.2%, respectively]). The use of staples, compared with suture, to close the skin significantly decreased the inflammation rate. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with in vitro conditions, in vivo conditions (where the environment is not controlled and triclosan may elute more quickly from the suture) may decrease the antibacterial effectiveness of triclosan-impregnated suture. On the basis of our findings, triclosan-impregnated sutures did not seem to provide an additional benefit for clinical use and cannot be strongly recommended for elective orthopedic procedures in veterinary medicine.

Evaluation of the histologic reactions to commonly used suture materials in the skin and musculature of ball pythons (Python regius).

OBJECTIVE: To evaluate histologic reactions to 8 suture materials and cyanoacrylate tissue adhesive (CTA) in the musculature and skin of ball pythons. ANIMALS: 30 hatchling ball pythons. PROCEDURES: In each snake, ten 1-cm skin incisions were made (day 0). At 8 sites, a suture of 1 of 8 materials was placed in the epaxial musculature, and the incision was closed with the same material. One incision was closed by use of CTA. No suture material was placed in the tenth incision, which was allowed to heal by second intention (negative control). Snakes (n = 5/group) were euthanized for harvest of treatment-site tissues at days 3, 7, 14, 30, 60, and 90. Skin and muscle sections were examined microscopically and assigned a subjective score (0 to 4) for each of the following: overall severity of inflammation, fibrosis, number of macrophages, number of granulocytes, number of perivascular lymphocytes, and degree of suture fragmentation. RESULTS: Subjective score analysis revealed that CTA did not cause a significant inflammatory response, compared with the negative control. All suture materials caused significantly more inflammation over all time points; for all suture materials, inflammatory response scores were significantly higher than values for the negative control 90 days after implantation. No sutures were completely absorbed by the end of the study period, and several sutures appeared to be in the process of extrusion. CONCLUSIONS AND CLINICAL RELEVANCE: In snakes, CTA can be used to close small superficial incisions or lacerations with minimal inflammatory response, and sutures may undergo extrusion from tissues prior to complete absorption.

Septic peritonitis: etiology, pathophysiology, and diagnosis.

Septic peritonitis is an inflammatory condition of the peritoneum that occurs secondary to microbial contamination. This clinically important condition has a wide variety of clinical courses as well as high morbidity and mortality due to secondary multiorgan dysfunction. This article reviews the etiology and pathophysiology of this condition and its diagnosis in small animals; a companion article addresses treatment and prognosis.

Septic peritonitis: treatment and prognosis.

Septic peritonitis is an inflammatory condition of the peritoneum that has a wide variety of clinical courses. The etiology and pathophysiology of this condition and its diagnosis in small animals are reviewed in a companion article. This article addresses the treatment of septic peritonitis and prognosis in small animals.

Clinical and histologic effects of intracardiac administration of propofol for induction of anesthesia in ball pythons (Python regius).

OBJECTIVE: To assess the clinical differences between induction of anesthesia in ball pythons with intracardiac administration of propofol and induction with isoflurane in oxygen and to assess the histologic findings over time in hearts following intracardiac administration of propofol. DESIGN: Prospective randomized study. ANIMALS: 30 hatchling ball pythons (Python regius). PROCEDURES: Anesthesia was induced with intracardiac administration of propofol (10 mg/kg [4.5 mg/lb]) in 18 ball pythons and with 5% isoflurane in oxygen in 12 ball pythons. Induction time, time of anesthesia, and recovery time were recorded. Hearts from snakes receiving intracardiac administration of propofol were evaluated histologically 3, 7, 14, 30, and 60 days following propofol administration. RESULTS: Induction time with intracardiac administration of propofol was significantly shorter than induction time with 5% isoflurane in oxygen. No significant differences were found in total anesthesia time. Recovery following intracardiac administration of propofol was significantly longer than recovery following induction of anesthesia with isoflurane in oxygen. Heart tissue evaluated histologically at 3, 7, and 14 days following intracardiac administration of propofol had mild inflammatory changes, and no histopathologic lesions were seen 30 and 60 days following propofol administration. CONCLUSIONS AND CLINICAL RELEVANCE: Intracardiac injection of propofol in snakes is safe and provides a rapid induction of anesthesia but leads to prolonged recovery, compared with that following induction with isoflurane. Histopathologic lesions in heart tissues following intracardiac injection of propofol were mild and resolved after 14 days.

Total ear canal ablation and lateral bulla osteotomy for treatment of otitis externa and media in a rabbit.

CASE DESCRIPTION: A 7-year-old spayed female Miniature Rex European rabbit (Oryctolagus cuniculus) was evaluated because of scratching at the right ear. Physical examination revealed purulent exudate in the right ear canal. CLINICAL FINDINGS: Microbial culture of the exudate yielded Pseudomonas aeruginosa susceptible to marbofloxacin; however, the infection was refractory to appropriate medical treatment. Computed tomography revealed isoattenuating material within the right tympanic bulla and external ear canal with no enhancement following IV administration of contrast medium. The left tympanic bulla appeared normal. TREATMENT AND OUTCOME: A total ear canal ablation and lateral bulla osteotomy were performed on the right ear, and polymethylmethacrylate beads containing either gentamicin or cefazolin were placed within the bulla and surrounding tissues. Two weeks after surgery, the patient appeared comfortable with no signs of scratching at the right ear. CLINICAL RELEVANCE: Total ear canal ablation and lateral bulla osteotomy can be successfully performed for treatment of chronic otitis externa and media in rabbits. Cartilage plates that compose the external ear canal, a bony acoustic duct, lack of a horizontal ear canal, and thickness of the lateral aspect of the tympanic bulla are features unique to rabbits and have not been described in relation to these surgical procedures in rabbits. Rabbits also produce a caseous exudate, and it is difficult to resolve infections of bone and soft tissues. Placement of antimicrobial-impregnated polymethylmethacrylate beads is recommended to minimize the risk of recurrent infection.

Segmental jejunal entrapment, volvulus, and strangulation secondary to intra-abdominal adhesions in a dog.

A 4 yr old, castrated male dachshund was presented for lethargy, restlessness, a "hunched" posture, and a painful abdomen. A gastric foreign body had been surgically removed 24 mo previously. Exploratory celiotomy revealed a devitalized segment of jejunum with twisted mesentery. Several adhesions and fibrous bands were present within the abdomen, presumptively from the previous gastric foreign body surgery. Histopathology determined that a fibrous tissue band caused entrapment of the segment of intestine and its mesentery resulting in volvulus and ischemic necrosis of the intestine. This case is unique because it involved a focal area of the jejunum that was incarcerated in fibrous adhesions.

Use of a duodenal serosal patch in the repair of a colon rupture in a female Solomon Island eclectus parrot.

Case Description-A 444-g (0.98-lb) 4-year-old sexually intact female Solomon Island eclectus parrot (Eclectus roratus solomonensis) was referred and evaluated for a suspected colonic obstruction. Clinical Findings-The parrot had a 3-day history of not passing feces and lack of appetite following treatment of dystocia that included percutaneous collapse of the egg and manual removal of egg fragments via the cloaca. During this procedure, a tear in the cloacal mucosa developed. The tear was repaired via a midline cloacotomy. Although clinically stable at the time of referral, the parrot became lethargic and bradycardic and had delayed crop emptying. Treatment and Outcome-A midline celiotomy and cloacotomy were performed to relieve the colonic obstruction, during which the severely distended colon ruptured. The colonic defects were closed in a simple interrupted pattern, and a serosal patch was applied by use of the adjacent duodenum. The bird recovered uneventfully from anesthesia and was passing voluminous feces with mildly increased effort within 1 hour after surgery. At 3 weeks after surgery, the parrot was passing feces with no increase in effort and had a normal appetite. Clinical Relevance-Application of a duodenal serosal patch for repair of a colon rupture was successful in this parrot. Gastrointestinal obstruction is rare in birds, but should be considered in birds that have regurgitation, decreased fecal production, and gastrointestinal dilation. Because birds lack an omentum, serosal patching with adjacent duodenum should be considered as a viable option in avian surgery.

Successful management of simple fractures of the femoral neck with femoral head and neck excision arthroplasty in two free-living avian species.

A red-tailed hawk (Buteo jamaicensis) and a Canada goose (Branta canadensis) were evaluated for unilateral pelvic limb lameness. Physical examination findings and results of diagnostic imaging revealed femoral neck fractures in both birds. Both birds were treated with a femoral head and neck excision arthroplasty. The affected legs were not immobilized, and the birds were encouraged to use the legs immediately after surgery to encourage formation of a pseudoarthrosis. Within 2 weeks, both birds were using the affected limb well enough to be either successfully released or transferred to a wildlife rehabilitation facility. Femoral head and neck excision arthroplasty without immobilization of the limb is recommended for managing avian femoral neck fractures, especially in free-ranging species in which a rapid and complete or near complete return to function is vital for survival in the wild.

Prepubic urethrostomy and vaginoplasty in a female cat.

A 1-year-old, intact female, domestic shorthaired cat was presented for dysuria resulting from perineal scarring subsequent to injuries incurred during a cat fight. A prepubic urethrostomy was performed to manage the dysuria. Eleven months later, the cat was re-presented with a 3-day history of pyrexia and inappetence. A pinpoint opening extending 0.5 cm ventral to the anus on midline, exuding a clear discharge, was noted in the perineal region. A contrast fistulogram was performed, and a vaginoperineal fistula was diagnosed. The fistulous tract was a result of vulvar stricture from the trauma of the cat fight. A vaginoplasty was performed to create an opening for vaginal secretions. This is the first published report of a prepubic urethrostomy performed in a female cat.

Medical and surgical management of otitis in captive bongo (Tragelaphus eurycerus).

Six cases of severe otitis media-interna, an uncommon problem in nondomestic ruminants, were diagnosed in five captive bongo (Tragelaphus eurycerus). The cases were geographically clustered at zoological facilities in Florida. A visible ear droop, head shaking, and otic discharge were common at clinical presentation. Medical management with prolonged systemic and topical antimicrobial therapy, combined with repeated manual removal of debris from the otic canal, was successful in resolving two cases and effectively controlled a third case. Two bongo with severe otitis did not respond to medical management and required surgical intervention. A bulla osteotomy and total ear canal ablation were performed on these animals (bilaterally in one bongo). Surgery was successful in providing complete clinical resolution of the otitis and is recommended for severe cases that fail to respond to less invasive management.