Robotic Nerve Sheath Tumor Resection With Intraoperative Neuromonitoring: Case Series and Systematic Review

Abstract

Background: Retroperitoneal nerve sheath tumors present a surgical challenge. Despite potential advantages, robotic surgery for these tumors has been limited. Identifying and sparing functional nerve fascicles during resection can be difficult, increasing the risk of neurological morbidity.

Objective: To review the literature regarding robotic resection of retroperitoneal nerve sheath tumors and retrospectively analyze our experience with robotic resection of these tumors using a manual electromyographic probe to identify and preserve functional nerve fascicles.

Methods: We retrospectively analyzed the clinical courses of 3 patients with retroperitoneal tumors treated at the National Institutes of Health by a multidisciplinary team using the da Vinci Xi system. Parent motor nerve fascicles were identified intraoperatively with a bipolar neurostimulation probe inserted through a manual port, permitting tumor resection with motor fascicle preservation.

Results: Two patients with neurofibromatosis type 1 underwent surgery for retroperitoneal neurofibromas located within the iliopsoas muscle, and 1 patient underwent surgery for a pelvic sporadic schwannoma. All tumors were successfully resected, with no complications or postoperative neurological deficits. Preoperative symptoms were improved or resolved in all patients.

Conclusion: Resection of retroperitoneal nerve sheath tumors confers an excellent prognosis, although their deep location and proximity to vital structures present unique challenges. Robotic surgery with intraoperative neurostimulation mapping is safe and effective for marginal resection of histologically benign or atypical retroperitoneal nerve sheath tumors, providing excellent visibility, increased dexterity and precision, and reduced risk of neurological morbidity.

Trial registration: ClinicalTrials.gov NCT00060541 NCT00924196 NCT02407405.

Copyright © Congress of Neurological Surgeons 2021. All rights reserved.

Figures

Graphical abstract

FIGURE 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram of search.

FIGURE 2.

Surgical anatomy of retroperitoneal nerve sheath tumors. A, Retroperitoneal zones. Zone 1 is the midline retroperitoneum and contains vascular structures, such as the abdominal aorta, inferior vena cava, proximal superior mesenteric artery, and proximal renal arteries, as well as viscera, such as the pancreas and duodenum. Zone 2 is located lateral to zone 1 on both sides and contains renal arteries and veins, kidneys and adrenals glands, and proximal ureters. Zone 3 is located in the pelvis and contains the iliac arteries and veins. Standard flank positioning and trocar configuration (inset, top) are used for tumors located in retroperitoneal zones 1 and 2, whereas supine positioning and trocar configuration (inset, bottom) are used for lesions located in retroperitoneal zone 3. The 10 to 12-mm trocar is indicated in red, 8 mm in gray, and 5 mm in yellow. B, Intraoperative scheme. The bipolar stimulating probe through a manual port for mapping tumor surface and the psoas muscle.

FIGURE 3.

Preoperative magnetic resonance images of included patients. Case 3: Coronal A and axial B T2 series demonstrating a plexiform neurofibroma (arrowheads) located in zone 2. Case 2: Contrast-enhanced coronal C and axial D T1 series showing a sporadic schwannoma (arrowheads) located in zone 2. Case 1: Contrast-enhanced coronal E and axial F T2 series showing a plexiform neurofibroma located in zone 3.