Step-by-step demonstration of "sciatic-nerve-preserved beyond-LEER" in a Thiel-embalmed cadaver: a novel salvage surgery for recurrent gynecologic malignancies

Abstract

Objective: Complete resection is the curative treatment choice for recurrent gynecological malignancies. Laterally extended endopelvic resection (LEER) is an effective surgical salvage therapy for lateral recurrence. However, when a recurrent tumor occupies the ischial spine and sacrum, LEER is not indicated, and surgical salvage therapy is abandoned. Theoretically, complete resection of such a tumor is possible by additional pelvic bone resection along with the standard LEER. Nevertheless, owing to the anatomical complexities of the beyond-LEER procedure, 2 major issues should be solved: sciatic nerve injury and tumor disruption during pelvic bone amputation. To overcome these technical challenges, we applied a multidirectional beyond-LEER approach, a novel salvage surgical procedure, with an aim of demonstrating its technical feasibility.

Methods: We created a simulation model of a laterally recurrent tumor that occupied the right ischial spine and sacrum in a Thiel-embalmed cadaver.

Results: Multidirectional approaches, including laparoscopic, perineal, and dorsal phases, were safely applied. We laparoscopically marked the L4-L5-S1 complex and S2 nerve with different colored tapes, and by pulling them out into a dorsal surgical field, the sciatic nerve was safely preserved. The dissection lines of the multidirectional approaches were aligned using tapes as landmarks, and complete tumor clearance without tumor disruption was accomplished. By following the cadaveric training, the first laparoscopic-assisted beyond-LEER procedure was successfully performed in a patient with recurrent ovarian cancer.

Conclusion: Using a Thiel-embalmed cadaver, we demonstrated the technical feasibility of a sciatic nerve-preserved beyond-LEER procedure, which was successfully performed in a patient with recurrent ovarian cancer.

Keywords: Cadaver; Laparoscopic Assisted; Sacrum; Salvage Therapy; Surgery.

Fig. 1. Mimicked recurrent tumor on the right side. The 7-cm mimicked recurrent tumor, which is made of green felt fabric, is fixed with a 2-0 polydioxanone thread to the right ischial spine, right sacrospinous ligament, right side of the sacrum and rectum, right internal obturator muscle, and uterine cervix on the right side.

Fig. 2. Right sciatic nerve marked with colored tapes. The L4-L5-S1 complex and S2 nerve are marked with yellow and red tapes, respectively.

Fig. 3. Anatomy around the right ischial spine from the back view. The right sciatic nerve is isolated and detached from the right ischial spine using the yellow tape as a landmark. (For ethical considerations, mosaic is included in this figure).

Fig. 4. The divided right ischial spine. The right ischial spine is divided using a bone chisel while preserving the sciatic nerve. (For ethical considerations, mosaic is included in this figure).

Fig. 5. The divided sacrum. (A) The location of the S2 sacral foramen is confirmed from the dorsal side using the red tape as a landmark. (B) The sacrum below S3 is divided using a bone chisel while preserving the S2 nerves. (For ethical considerations, mosaic is included in this figure).

Fig. 6. Final operation view. Total pelvic exenteration and beyond-laterally extended endopelvic resection procedure were accomplished on the right side.