Surgical Treatment of Piriformis Syndrome

Abstract

Background: Piriformis syndrome (PS) is an uncommon disease characterized by symptoms resulting from compression/irritation of the sciatic nerve by the piriformis muscle. Uncertainty and controversy remain regarding the proper diagnosis and most effective form of treatment for PS. This study analyzes the diagnostic methods and efficacy of conservative and surgical treatments for PS.

Methods: From March 2006 to February 2013, we retrospectively reviewed 239 patients who were diagnosed with PS and screened them for eligibility according to our inclusion/exclusion criteria. All patients underwent various conservative treatments initially including activity modification, medications, physical therapy, local steroid injections into the piriformis muscle, and extracorporeal shock wave therapy for at least 3 months. We resected the piriformis muscle with/without neurolysis of the sciatic nerve in 12 patients who had intractable sciatica despite conservative treatment at least for 3 months. The average age of the patients (4 males and 8 females) was 61 years (range, 45 to 71 years). The average duration of symptoms before surgery was 22.1 months (range, 4 to 72 months), and the mean follow-up period was 22.7 months (range, 12 to 43 months). We evaluated the degree of pain and recorded the responses using a visual analog scale (VAS) preoperatively and 3 days and 12 months postoperatively.

Results: Buttock pain was more improved than sciatica with various conservative treatments. Compared with preoperatively, the VAS score was significantly decreased after the operation. Overall, satisfactory results were obtained in 10 patients (83%) after surgery.

Conclusions: PS is thought to be an exclusively clinical diagnosis, and if the diagnosis is performed correctly, surgery can be a good treatment option in patients with refractory sciatica despite appropriate conservative treatments.

Keywords: Piriformis muscle; Piriformis muscle syndrome; Sciatic nerve.

Fig. 1. Intraoperative photographs. (A) The tensor fascia lata was incised in continuity where it overlays the trochanter, and the piriformis muscle (P) was inserted into the posterior aspect of the greater trochanter (GT) and located above the superior gemellus muscle (SG) and obturator internus tendon (OI). (B) After division of the tight piriformis tendon at the insertion site at its tendinous portion, a distally adherent sciatic nerve (S) with engorged epineurial vessels was observed. QF: quadratus femoris.

Fig. 2. Physical examination. The location of a tender point (x) in the gluteal area, particularly on the iliac side of the sacroiliac joint (SI), is consistent with that of the piriformis muscle. IC: iliac crest, IT: ischial tuberosity, GT: greater trochanter, PSIS: posterior superior iliac spine.

Fig. 3. Algorithm for the diagnosis and treatment of piriformis syndrome (PS). CT: computed tomography, MRI: magnetic resonance imaging, EMG: electromyography, PT: physical therapy, ESWT: extracorporeal shock wave therapy.

Fig. 4. Magnetic resonance imaging shows that the left sciatic nerve is entrapped, and perineural vessels are engorged (arrow) by the piriformis muscle in a 45-year-old female. LPH: lumbopelvic hip.