Retroperitoneoscopy of the presacral space in horses: Surgical access and anatomy.

BACKGROUND: Surgical approaches to the equine rectum and perirectal area are described in the literature. However, surgeries in this region can be challenging. OBJECTIVE: To describe the surgical anatomy of the presacral space and to evaluate its access using a retroperitoneoscopic approach. STUDY DESIGN: Ex vivo experiment. METHODS: Preliminary dissections were performed in two cadavers to define the boundaries of the presacral space and to determine portal locations for the surgical approach. After that, nine cadavers were used for experimental presacral retroperitoneoscopic procedure in a standing position. Following retroperitoneoscopy, cadavers were dissected to confirm the anatomical structures observed during the endoscopic procedures, to control the location of each portal and to record iatrogenic trauma. RESULTS: The presacral space was bordered by the vertebral column from the ventral aspect of lumbosacral promontorium to the first coccygeal vertebra dorsally and by the presacral fascia and peritoneum ventrally. Lateral limits were composed of the sacrosciatic ligament and transversalis fascia. Cranial and caudal borders were composed of the peritoneum and coccygeal and levator ani muscles respectively. Retroperitoneoscopic portals were placed between the external anal sphincter and semimembranosus muscles and between the base of the tail and the external anal sphincter muscle through the anococcygeal fascia to enter the space by its caudal border. The retroperitoneal space was reached in all cases and the dorsal and lateral aspects of the rectum were visualised after creation of a working space. MAIN LIMITATIONS: Use of cadaver specimens do not permit to evaluate the tolerance in living animals and the surgical complications such as rectal damage, haemorrhage and infection. CONCLUSION: This study provides an anatomical description and surgical access of the presacral space with a minimal invasive approach. Retroperitoneoscopy allows access to the rectum and the dorsal aspect of the pelvis.

Retroperitoneoscopy in the horse: Anatomical study of the retroperitoneal perirenal space and description of a surgical approach.

BACKGROUND: Surgical approaches to the kidneys and perirenal structures are uncommonly performed in horses and several complications have been described with the current procedures. OBJECTIVE: To describe the anatomy of the retroperitoneal perirenal space and investigate a retroperitoneal minimally invasive approach to access the kidney and perirenal structures in horses. STUDY DESIGN: Descriptive, cadaveric study. METHODS: Anatomical description of the retroperitoneal space was performed on three equine cadavers and the surgical approach was developed based on these dissections. Ten cadaveric horses underwent a retroperitoneoscopy. Five horses were placed in a right lateral recumbency position to explore the left retroperitoneal space and five horses were placed in a standing position to explore both left and right sides. Anatomical landmarks, working space and access to the renal hilus and perirenal structures were evaluated. RESULTS: Dissections revealed that kidneys are surrounded by a renal fascia which delimits two spaces: a perirenal space between the kidney and the renal fascia, and a pararenal space between the renal fascia and psoas muscles or peritoneum. The retroperitoneoscopic portal was placed at the level of the dorsal aspect of the tuber coxae, 3 cm caudal to the last rib for the left side and 2 cm caudal to the last rib for the right side. Retroperitoneal access and working space were successfully established in all horses. The standing position allowed an easier dissection than lateral recumbency. Division of the perirenal fat allowed access to the kidney and adrenal glands as well as individualisation of renal vessels and ureter in the renal hilus. MAIN LIMITATIONS: Study of cadavers precluded appreciation of haemorrhage or use the pulsating vessels as landmarks. CONCLUSIONS: This study provides a description of the retroperitoneal perirenal space and describes a new surgical approach to access kidneys and perirenal structures in horses.