Nondiscogenic Sciatica: What Clinical Examination and Imaging Can Tell Us?

Abstract

Lesions affecting the sciatic nerve (SN) can mimic lumbar radiculopathy. In patients presenting with sciatica, approximately 10% have a nondiscogenic etiology. Through neurological examination and imaging, it may be possible to confirm nondiscogenic sciatica (NDS). This study aims to present a series of 6 patients with infragluteal NDS, highlighting clinical and imaging aspects that may suggest this diagnosis. This is a retrospective study of 6 patients treated for NDS from 2010 to 2018. The mean and median ages were 41.2 and 38.5 years, respectively, with all patients female. All patients presented with sciatic pain, tenderness to deep infragluteal palpation, and a positive Tinel's sign related to the SN. Four patients were referred for surgical treatment, whereas 1 underwent pharmacological therapy and 1 underwent incisional biopsy and radiotherapy. In our series, 6 different causes for NDS were diagnosed: 1 nontumorous cause: extrauterine endometriosis and 5 tumors: metastasis from rectal adenocarcinoma, low-grade sarcoma, schwannoma, high-grade sarcoma, and myxoma. Differentiating between discogenic and NDS can be challenging for clinicians. When patients present with sciatic pain, a Tinel's sign related to the SN elicited at the deep infragluteal region, tenderness to deep infragluteal palpation, occasionally with an SN motor deficit and imaging findings of the lumbar spine that do not justify a discogenic source, the cause should be considered nondiscogenic and they should be scheduled for magnetic resonance imaging of the gluteal and pelvic region.