Robotic Excision of a Sciatic Schwannoma and Deep Infiltrating Endometriosis: A Neuropelveology Approach
Chronic pelvic pain often presents as a diagnostic dilemma when multiple pain pathways overlap. When deep infiltrating endometriosis (DIE) coexists with lower extremity radiculopathy, surgical teams frequently attribute neuropathic symptoms entirely to endometriotic infiltration of the lumbosacral plexus. However, complex pelvic pain can be multifactorial.
A recent surgical video published in the Journal of Minimally Invasive Gynecology (JMIG) by Abraão, Maluf Perin, Barbisan, and Vidali illustrates a rare presentation: a 32-year-old patient suffering from debilitating chronic pelvic pain (VAS 8–10) featuring catamenial exacerbation alongside distinct, non-cyclical neuropathic pain radiating across the left L5–S2 dermatomes.
While magnetic resonance imaging confirmed the presence of pelvic DIE, it revealed a concomitant 2.0 × 1.5 cm well-circumscribed, hyperintense lesion on T2-weighted imaging along the course of the left sciatic nerve at the greater sciatic foramen—radiologically consistent with a peripheral nerve sheath tumor (schwannoma).
Overcoming the Surgical Access Dilemma
Peripheral nerve tumors within the greater sciatic foramen are historically treated via an open transgluteal neurosurgical approach. While effective for gluteal lesions, a transgluteal incision requires extensive transection of the gluteus maximus and adjacent pelvic rotators, involves substantial post-operative recovery, and does not allow for concurrent intervention within the peritoneal cavity.
Opting for a minimally invasive alternative, the surgical team utilized a four-arm robotic platform configured in a W-shaped layout. This transperitoneal neuropelveologic approach enabled radical excision of deep endometriosis, complete exploration of the lumbosacral fossa, decompression of pelvic vascular entrapment, and targeted neurolysis of the sciatic nerve—all within a single, 120-minute procedure without changing trocar configurations.
Video can be found HERE: https://www.jmig.org/article/S1553-4650(26)00507-8/fulltext
Step-by-Step Surgical Progression
1. Peritoneal Exploration and DIE Excision
The procedure began with an inspection of the peritoneal cavity, revealing deep infiltrating endometriosis involving the left ovarian fossa and rectovaginal septum. The peritoneum medial to the infundibulopelvic ligament was opened to access the left pararectal space. Under indocyanine green (ICG) fluorescence visualization, the left ureter was mobilized laterally, allowing thorough resection of endometriosis and opening of Okabayashi’s space bordered by the uterine artery, ureter, and hypogastric nerve.
2. Accessing the Lumbosacral Fossa
To reach the deep somatic nerves, peritoneal incision was extended superiorly along the external iliac artery. Blunt dissection between the external iliac vessels and the psoas muscle opened the retroperitoneal lumbosacral fossa. The genitofemoral and obturator nerves were identified as primary landmarks to establish clear surgical margins.
3. Vascular Neurolysis & Decompression
Proceeding caudally along avascular planes toward the sciatic nerve (formed by the convergence of the L4–S2 roots), surgeons uncovered an anomalous superior gluteal vein crossing directly over the nerve trunk, generating extrinsic vascular compression. The anomalous vessel was systematically dissected and ligated, releasing mechanical entrapment prior to tumor manipulation.
4. Robotic Sciatic Schwannoma Enucleation
The schwannoma was exposed within the narrow, angulated boundary of the greater sciatic foramen deep to the piriformis muscle. Exploiting the articulated endo-wrist instruments and 3D magnification of the robotic system, the tumor capsule was carefully defined. Minimal traction was applied using tenaculum forceps while an extracapsular dissection plane was developed. Cold scissors were prioritized around functional nerve fibers to prevent thermal and traction injury to intact neuro-fascicles. Once completely enucleated, the specimen was placed in an endobag and retrieved intact.
Clinical Outcomes and Systematic Differential Diagnosis
Post-operative recovery showed dramatic and rapid clinical improvement:
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Immediate Radicular Relief: The patient experienced complete resolution of lower-extremity neuropathic pain immediately after surgery.
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VAS Reduction: Chronic pain scores decreased from 10/10 preoperatively to 1/10 at one-month follow-up.
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Neurologic Preservation: Functional motor assessment remained intact, with only transient, minor hypoesthesia in the affected dermatome.
This case demonstrates the clinical power of systematic neuropelveologic diagnostics. While the patient presented with active deep infiltrating endometriosis, her radiating neuropathic symptoms stemmed entirely from extrinsic vascular compression and an intrapelvic schwannoma. Utilizing advanced robotic platforms enables skilled pelvic surgeons to reach tight retroperitoneal spaces like the greater sciatic foramen, delivering comprehensive multi-etiology symptom resolution in a single minimally invasive setting.
