Intraneural Ganglion Cysts Arising from the Hip Joint as Rare Causes of Sciatic Neuropathy

Background: Sciatic neuropathy can result from pressure, injury, or inflammation around the sciatic nerve. In rare instances, sciatic neuropathy is caused by an intraneural ganglion cyst (IGC) originating from the hip joint. However, an effective treatment modality for this condition has not yet been established. The purpose of the present study was to evaluate the clinical and radiographic outcomes of hip arthroscopy for the treatment of IGCs involving the sciatic nerve. Methods: We reviewed the records on a consecutive series of hip arthroscopy procedures that had been performed by a single surgeon for the treatment of sciatic IGCs between July 2016 and February 2022. Thirteen Asian patients (13 hips) with symptomatic sciatic neuropathy were included. During arthroscopic surgery, IGCs were decompressed by enlarging their periarticular connection. Magnetic resonance imaging (MRI) and electrodiagnostic evaluation were routinely performed. The visual analog scale (VAS) for pain and modified Harris hip score (mHHS) were used for clinical evaluations. The mean age at the time of surgery was 57 years (range, 23 to 72 years), and the mean duration of follow-up was 41 months (range, 24 to 87 months). Results: The mean VAS score decreased from 8.3 preoperatively to 1.9 at the latest evaluation (p < 0.001). Satisfactory pain relief was reported by 12 patients (92%), including 9 patients (69%) who had complete remission. Four of the 6 patients with sensory impairment and 3 of the 4 patients with motor weakness reported complete recovery. The mean mHHS improved from 51.5 to 94.1 (p < 0.001). In MRI comparisons, the mean largest diameter and length of IGCs decreased from 2.6 to 0.5 cm (p < 0.001) and from 6.8 to 0.6 cm (p < 0.001), respectively. IGCs completely disappeared on MRI in 9 patients (69%). The latest electrodiagnostic studies confirmed improvement in all 12 patients with preoperative abnormalities. One patient (8%) with symptomatic recurrence was successfully treated with revision arthroscopic decompression. Conclusions: In patients with sciatic neuropathy, the possibility of IGCs arising from the hip should be considered. Our findings suggest that arthroscopic hip surgery is a less-invasive and more-effective treatment for relieving neuropathic pain and neurological deficits associated with sciatic IGCs. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.