Background: Retroperitoneal and pelvic schwannomas and neurofibromas account about 10% of all retroperitoneal tumors. These tumors are almost invariably benign and slow growing. They are either asymptomatic or cause radicular or abdominal pain. The radiologic findings cannot distinguish schwannomas from other retroperitoneal neoplasms. To our knowledge, this study is the first neurosurgical series of this size to employ intraoperative electrophysiological monitoring during resection of schwannomas and neurofibromas arising in the retroperitoneal and pelvic regions.
Methods: A retrospective study conducted at the University Hospital Göttingen from 2015 to 2024 included 13 patients who underwent surgical treatment for schwannomas and neurofibromas arising in the retroperitoneal and pelvic regions. The study incorporated detailed surgical descriptions of the resection techniques and the approaches used for these tumors.
Results: The mean age was 51 ± 12 years. Symptomatic presentations included abdominal discomfort in 6 patients (46%), unilateral radicular pain in 5 patients (38%), and 4 patients (31%) were asymptomatic. Tumors exhibited a mean diameter of 6.2 ± 2.9 cm (range: 3.3-14 cm). Anatomic distribution included 7 cases (54%) in the presacral region, 5 cases (38%) in the lesser pelvis, and 4 cases (31%) involving the L5 or S1 neuroforamen with extension into the ventral prevertebral space. Transretroperitoneal approaches were utilized in 8 cases (62%), while 5 (38%) underwent transperitoneal resection. Gross total resection was achieved in 10 patients (77%). In one patient, a transient intraoperative decline in sphincter MEPs was observed, with a 48% drop in amplitude, followed by full postoperative recovery. Direct electrical stimulation of the tumor capsule elicited active motor responses in 5 patients (38%). In 3 of these cases, complete resection was not feasible due to intraoperative changes in MEPs signals. The mean operative duration was 271.8 ± 64.5 min (range: 180-400 min), with a mean blood loss of 700 ± 400 mL. Postoperatively, no motor or sensory deficits occurred, and symptoms resolved within one week. The mean hospital stay was 9.2 ± 3.5 days (range: 5-15 days). Histopathology confirmed benign tumors in all cases: 8 schwannomas (62%), 3 neurofibromas (23%), and 1 ganglioneuroma (8%). No recurrences were observed during a mean follow-up period of 24 ± 6 months.
Conclusion: Surgical resection of retroperitoneal and pelvic schwannomas and neurofibromas, while technically challenging, is safe and effective when performed by experienced surgeons and multidisciplinary preoperative planning. None of our patients experienced postoperative complications, which may, in part, be attributable to the use of intraoperative neuromonitoring. However, comparative and prospective studies are recommended to further validate these findings.
Keywords: Retroperitoneal and pelvic schwannoma; Schwannoma; Surgical strategies.
© 2025. The Author(s).