Comparison of design features and mechanical properties of commercially available Veress needles.

OBJECTIVE: To compare design features and mechanical properties of 13 commercially available Veress needles (VN). STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Veress needles from 9 manufacturers (6 reusable, 6 disposable, and 1 with a reusable stylet combined with a disposable cannula) were included in the study. METHODS: Veress needles are designed with a spring-loaded stylet to protect the tip of the cannula following insertion into the abdomen. Stylet forces were measured with a scale in a test jig by moving the stylet in 0.5 mm steps into the hollow cannula. Forces and spring rates were derived from force-displacement plots. Mass, mechanical dimensions, and the bevel angle and geometry were assessed. Differences between VN models were analyzed with a univariate analysis of variance. Results are reported as mean ± SD or median (range). RESULTS: Physical and mechanical parameters differed between models. The exposed stylet length was 3.5 mm (2-7). Three bevel geometries (bias, lancet type, and back-cut) with angles between 20° and 40° were identified. Reusable VN weigh more (24.9 ± 2.2 g) than disposable designs (6.0 ± 2.3 g). The mean values for the spring rate and the residual stylet force were 0.23 ± 0.08 Nmm-1 and 0.94 ± 0.28 N, respectively. The mean force required to move the stylet to the cannula tip was 1.81 ± 0.29 N and 2.77 ± 0.54 N to move to the proximal end of the bevel. CONCLUSION: Commercially available VN use diverse bevel geometries and have different mechanical characteristics. Studies investigating laparoscopic entry complications should explicitly report the type of VN model used.

Influence of body weight and body conformation on the pressure-volume curve during capnoperitoneum in dogs.

OBJECTIVE To evaluate the pressure-volume relationship during capnoperitoneum in dogs and effects of body weight and body conformation. ANIMALS 86 dogs scheduled for routine laparoscopy. PROCEDURES Dogs were allocated into 3 groups on the basis of body weight. Body measurements, body condition score, and body conformation indices were calculated. Carbon dioxide was insufflated into the abdomen with a syringe, and pressure was measured at the laparoscopic cannula. Volume and pressure data were processed, and the yield point, defined by use of a cutoff volume (COV) and cutoff pressure (COP), was calculated. RESULTS 20 dogs were excluded because of recording errors, air leakage attributable to surgical flaws, or trocar defects. For the remaining 66 dogs, the pressure-volume curve was linear-like until the yield point was reached, and then it became visibly exponential. Mean ± SD COP was 5.99 ± 0.805 mm Hg. No correlation was detected between yield point, body variables, or body weight. Mean COV was 1,196.2 ± 697.9 mL (65.15 ± 20.83 mL of CO2/kg), and COV was correlated significantly with body weight and one of the body condition indices but not with other variables. CONCLUSION AND CLINICAL RELEVANCE In this study, there was a similar COP for all dogs of all sizes. In addition, results suggested that increasing the abdominal pressure after the yield point was reached did not contribute to a substantial increase in working space in the abdomen. No correlation was found between yield point, body variables, and body weight.

Innovative approach to laparoscopic adrenalectomy for treatment of unilateral adrenal gland tumors in dogs.

OBJECTIVE: To report a technique for, and short-term outcome of unilateral laparoscopic adrenalectomy in dogs positioned in sternal recumbency without abdominal support. STUDY DESIGN: Experimental and prospective clinical study. ANIMALS: Healthy dogs (n = 5) and dogs with unilateral adrenal gland tumor (n = 9). METHODS: Anesthetized dogs were positioned in sternal recumbency with 2 cushions placed under the dog to elevate the chest and pelvic area so that the abdomen was not in contact with the surgical table allowing gravitational displacement of the abdominal viscera. Three 5-mm portals were located in the paralumbar fossa. Adrenal glands were carefully dissected and surrounding tissues sealed and cut using a vessel-sealing device. A retrieval bag or part of a surgical glove finger was used to remove the adrenal gland from the abdomen. Surgical time and complications were recorded, and short-term outcome assessed. RESULTS: Adrenal glands in normal dogs and unilateral adrenal tumors (8 left, 1 right) not involving the caudal vena cava in affected dogs were successfully removed laparoscopically. There were no major intraoperative complications. Of the dogs with adrenal tumors, 1 dog died within 24 hours of surgery from unrelated causes. Eight dogs recovered within 1 day and were discharged within 72 hours. Surgical times ranged from 42 to 117 minutes and were significantly shorter than those reported previously. CONCLUSIONS: Positioning anesthetized dogs in sternal recumbency with the abdomen suspended to facilitate gravitational displacement of the abdominal viscera improves access to, and visibility of, the adrenal gland for laparoscopic removal.

Laparoscopic adrenalectomy for treatment of unilateral adrenocortical carcinomas: technique, complications, and results in seven dogs.

OBJECTIVE: To investigate the feasibility of, and outcome after, laparoscopic adrenalectomy in dogs with unilateral adrenocortical carcinoma. STUDY DESIGN: Case series. ANIMALS: Dogs (n=7) with Cushing's syndrome caused by unilateral adrenocortical carcinoma. METHODS: Laparoscopic adrenalectomy with the dog in lateral recumbency on the unaffected side. Three 5-mm portals (1 laparoscopic portal, 2 instrument portals) were placed in the paralumbar fossa. A fourth instrumental portal (5-12 mm) was placed above the kidney. After dissection and hemostatic control of the phrenicoabdominal vein, the adrenal gland was carefully dissected or when there was capsule fragility, necrotic content was partially aspirated. The remaining glandular tissue was removed through the 12-mm trocar site. RESULTS: Dogs with unilateral adrenocortical carcinoma (3 right-sided, 4 left-sided) without invasion of the caudal vena cava were successfully operated by laparoscopic approach. There were no significant intraoperative complications; 2 dogs died within 48 hours of surgery because of respiratory complications. Five dogs were discharged 72 hours after surgery, and signs of hyperadrenocorticism disappeared thereafter (survival time ranged from 7 to 25 months). CONCLUSIONS: Laparoscopic adrenalectomy is feasible in dogs with either right- or left-sided adrenocortical carcinoma not involving the caudal vena cava. CLINICAL RELEVANCE: When performed by experienced surgeons, laparoscopic adrenalectomy offers a minimally invasive alternative to open laparotomy or retroperitoneal surgery for the treatment of unilateral adrenocortical carcinoma in dogs.

Use of laparotomy in a staged approach for resolution of bilateral or complicated perineal hernia in 41 dogs.

OBJECTIVE: To evaluate the value of laparotomy as the initial step in the treatment of bilateral or complicated perineal hernia (PH) in dogs. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: Forty-one dogs with PH. METHODS: Dogs with bilateral or complicated PH treated by a 2-step approach between November 1997 and December 2001 were studied. Inclusion criteria for complicated PH were: recurrence of PH, unilateral PH with a major rectal dilatation, PH with a concurrent surgical prostatic disease, and PH with retroflexed bladder. Colopexy, vas deferens pexy, cystopexy, and prostatic omentalization were performed during laparotomy as needed. Later, PH was performed by internal obturator muscle flap (IOMF) or if there was a perineal rent or weakness on the contralateral side, appositional herniorrhaphy was performed. Outcome was followed for >/=6 months. RESULTS: PH were bilateral (20 dogs) or unilateral (21). Twenty-one (51%) dogs had prostatic disease (clinical or ultrasonography diagnosis; 17 confirmed histologically) and 12 (29%) had urinary bladder retroflexion. Forty-one colopexies, 32 vas deferens pexies, 6 cystopexies, and 9 prostatic surgeries (omentalization or perineal cyst resection) were performed. PH was performed 2-20 days (median, 6 days) later: 61 IOMF transpositions, 13 appositional. Mean follow-up time was 26.6 months (range, 6-54 months, median, 27 months). PH was resolved in 37 (90%) dogs; 4 dogs had recurrence, and all occurred within 6 months. Thirty-eight (92%) dogs had an improved quality of life (good in 34 dogs, fair in 4 dogs). Wound complications occurred in 7 dogs (17%). Postoperative urine dribbling occurred in 15 dogs (37%) and was irreversible in 7 dogs (17%). Postoperative fecal straining persisted in 18 dogs (44%), and was permanent in 4 dogs (10%). Fecal incontinence did not occur. CONCLUSIONS: In bilateral or complicated PH, fixation of the urinary bladder and colon, and treatment of prostatic disease increase the chances of resolution. Emptying of the perineal space by organ pexy allows improved observation during herniorrhaphy. Despite a 90% clinical resolution, dogs with complicated PH treated by a 2-step protocol may have persistent urinary and fecal disorders. CLINICAL RELEVANCE: To improve the prognosis of bilateral or complicated PH, investigation and treatment of concomitant lesions (rectal, prostatic, bladder) should be part of a rational surgical strategy using a 2-step protocol.

Thoracoscopic treatment of bullous emphysema in 3 dogs.

OBJECTIVE: To report thorascopic partial lobectomy for treatment of bullous emphysema in dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Three dogs with spontaneous pneumothorax. METHODS: Thoracoscopy without pulmonary exclusion was used to identify bulla. The thorascope was introduced into the thorax lateral to the xyphoid process, and instrument portals were made at different levels along the thoracic wall between the third and tenth intercostal spaces. The thorascope was passed through the mediastinum to view the opposite pleural cavity. After identification of bullae, the affected lung was excised using an endoscopic stapler, and the incision line was checked for air leakage. Thoracic drains were used for air aspiration for 2 days after surgery. RESULTS: Bullae were confirmed histologically as emphysematous lesions. Lung inflation did not interfere with identification of bullae or with surgery. All dogs had full recovery without recurrence for 18 to 29 months after surgery. CONCLUSIONS: Identification and ablation of bulla can be performed thoracoscopically without pulmonary exclusion in dogs. CLINICAL RELEVANCE: Thoracoscopy offers several advantages compared with thoracotomy for treatment and diagnosis of idiopathic pneumothorax, including ease of identification of bullae and reduced postoperative pain and morbidity.