ObjectiveTo develop and describe a laparoscopic retroperitoneal access technique, investigate working space establishment, and describe the surgical anatomy in the retroperitoneal space as an initial step for clinical application of retroperitoneal laparoscopy in dogs.Study DesignCadaveric and experimental study.AnimalsCadaveric (n=8) and healthy (n=6) adult dogs.MethodsThe retroperitoneal access technique was developed in 3 cadavers based on the human technique and transperitoneal observation. Its application and working space establishment with carbon dioxide (CO2) insufflation alone was evaluated in 5 cadavers by observing with a transperitoneal telescope and in 6 live dogs by repeated computed tomography (CT) scans at pressure of 0, 5, 10, and 15 mmHg. Recordings of retroperitoneoscopy as well as working space volume and linear dimensions measured on CT images were analyzed.ResultsRetroperitoneal access and working space establishment with CO2 insufflation alone were successfully performed in all 6 live dogs. The only complication observed was in 1 dog that developed subclinical pneumomediastinum. As pressure increased, working space was established from the ipsilateral to the contralateral side, and peritoneal tearing eventually developed. Working space volume increased significantly from 5 mmHg and linear dimensions increased significantly from 0 to 10 mmHg. With pneumo‐retroperitoneum above 5 mmHg, retroperitoneal organs, including kidneys and adrenal glands, were easily visualized.ConclusionThe retroperitoneal access technique and working space establishment with CO2 insufflation starting with 5 mmHg and increasing to 10 mmHg provided adequate working space and visualization of retroperitoneal organs, which may allow direct access for retroperitoneal laparoscopy in dogs.

ObjectiveTo evaluate the feasibility of single‐port retroperitoneoscopic adrenalectomy (SPRA) in dogs.Study DesignA pilot experimental study.AnimalsEight healthy beagle dogs.MethodsSPRA was performed on the left and right sides (4 dogs each). Resection of the adrenal gland was performed through a SILS port using a retroperitoneal approach. Operative time was defined from skin incision to the completion of skin suture. Postoperative pain was evaluated by using 3 pain scores. Integrity of the adrenal gland capsule was evaluated by histologic assessment.ResultsMean time taken to complete the SPRA was 44.1 minutes (range, 37‐51) and was significantly longer on the right side than on the left side (P < .05). There were no complications intraoperatively or during 14 days of postoperative monitoring. The adrenal gland capsule was found to be injured in 3 of the 8 dogs by histologic assessment.ConclusionThis is the first report of SPRA in the veterinary literature. With this technique it is possible to perform adrenalectomy with some risk of capsule penetration and with excellent visibility.Clinical significanceThis study suggests that SPRA is feasible and can be used to resect small adrenal tumors with minimal complications.

The aim of this study was to describe a ventral laparoscopic technique for bilateral medial iliac lymphadenectomy in dogs. Twelve intact male purpose-bred research dogs, weighing less than 15 kg, were positioned in dorsal recumbency, and a 3-portal technique was used. Bilateral dissection was performed with vessel-sealing devices while tilting the surgical table by up to 30° towards the contralateral side of the target medial iliac lymph node (MILN) without changing the surgeon’s position. Using a ventral laparoscopic approach, bilateral MILNs were identified and excised in all dogs. The mean times for unilateral and bilateral MILN dissections were 9.7 ± 3.8 and 21.0 ± 6.0 min, respectively. The mean times for the right and left MILN dissections were 10.8 ± 4.3 and 9.8 ± 2.5 min, respectively. The mean total surgery time was 43.7 ± 7.7 min. In total, 26 MILNs were dissected. Several complications, including mild to moderate capillary hemorrhage from perinodal fat and vessels (controlled laparoscopically), mild spleen trauma caused by the first trocar insertion and capsular damage of MILNs, were observed. However, there were no other major complications. All MILN samples were evaluated and deemed suitable for histopathologic diagnosis. Laparoscopic excision of MILNs is a useful method of excisional biopsy for histopathologic diagnosis. Using this ventral laparoscopic approach with the 3-portal technique, bilateral MILN dissection suitable for obtaining histopathologic samples could be achieved in a short time in dogs weighing less than 15 kg.

This study assessed the effects of retroperitoneal carbon dioxide (CO 2 ) insufflation on cardiopulmonary variables and intra-abdominal pressure (IAP) in mechanically ventilated dogs in sternal recumbency with the abdomen unsupported, following placement of a positioning kit and towels under the pectoral and pelvic regions. General anesthesia was induced in eight healthy adult male Beagles. A Swan-Ganz catheter was placed in the pulmonary artery via the jugular vein for cardiac output measurements. A Foley urethral catheter was placed to monitor transvesical IAP. A 10 mm balloon blunt-tip trocar was inserted into the retroperitoneal space. With a fixed respiratory rate and tidal volume by mechanical ventilation, insufflation pressure was sequentially increased from 0 to 10 mmHg in 5 mmHg increments, followed by desufflation. All variables were measured before insufflation, 5 min after the establishment of each insufflation pressure, and after desufflation. At 10 mmHg, the IAP was nearly equal to insufflation pressure. Cardiopulmonary function was not compromised at any point, although the cardiac index (CI), heart rate, mean arterial pressure (MAP), and mean pulmonary arterial pressure increased within normal ranges. End-tidal CO 2 concentration, arterial CO 2 partial pressure, and oxygen delivery index (DO 2 I) increased, whereas pH decreased, at 10 mmHg. CI, MAP, and DO 2 I did not recover to baseline after decompression. Thus, retroperitoneal CO 2 insufflation up to 10 mmHg is well tolerated by mechanically ventilated dogs positioned in sternal recumbency with the abdomen unsupported, although sympathetic changes may occur with an insufflation pressure increase.