The Endoscopic Treatment of Sciatic Nerve Entrapment/Deep Gluteal Syndrome

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Arthroscopy. 2010 Nov 9. [Epub ahead of print]

The Endoscopic Treatment of Sciatic Nerve Entrapment/Deep Gluteal Syndrome.

Martin HDShears SAJohnson JCSmathers AMPalmer IJ.

Abstract

PURPOSE: The purpose of this study was to investigate the historical, clinical, and radiographic presentation of deep gluteal syndrome (DGS) patients, describe the endoscopic anatomy associated with DGS, and assess the effectiveness of endoscopic surgical decompression for DGS.

METHODS: Sciatic nerve entrapment was diagnosed in 35 patients (28 women and 7 men). Portals for inspection of the posterior peritrochanteric space (subgluteal space) of the hip were used as well as an auxiliary posterolateral portal. Patients were treated with sciatic nerve decompression by resection of fibrovascular scar bands, piriformis tendon release, obturator internus, or quadratus femoris or by hamstring tendon scarring. Postoperative outcomes were evaluated with the modified Harris Hip Score (MHHS), verbal analog scale (VAS) pain score, and a questionnaire related specifically to sciatic hip pain.

RESULTS: The mean patient age was 47 years (range, 20 to 66 years). The mean duration of symptoms was 3.7 years (range, 1 to 23 years). The mean preoperative VAS score was 6.9 ± 2.0, and the mean preoperative MHHS was 54.4 ± 13.1 (range, 25.3 to 79.2). Of the patients, 21 reported preoperative use of narcotics for pain; 2 continued to take narcotics postoperatively (unrelated to initial complaint). The mean time of follow-up was 12 months (range, 6 to 24 months). The mean postoperative MHHS increased to 78.0 and VAS score decreased to 2.4. Eighty-three percent of patients had no postoperative sciatic sit pain (inability to sit for >30 minutes).

CONCLUSIONS: Endoscopic decompression of the sciatic nerve appears useful in improving function and diminishing hip pain in sciatic nerve entrapment/DGS.

LEVEL OF EVIDENCE: Level IV, therapeutic case series

Comments

Mikael Nordfors's picture

 

Gross appearance of the sciatic nerve before decompression was observed as follows: adhesed over ischium posteriorly and inferiorly, branched with multiple branches encased in scar tissue, adhesed lateral to ischium with no excursion, hypovascular in appearance, or significantly entrapped by scar tissue. In 27 patients the greater trochanteric bursa was found to be excessively thickened with fibrous scar bands appearing to extend to near the sciatic nerve (Fig 3). The sciatic nerve was entrapped by the piriformis tendon on the nerve (Fig 4) in 18 patients. Characteristics of the piriformis muscle included split, bulging split with the sciatic nerve passing through the body, split tendon with an anterior and posterior component in which the anterior portion was released, and split into 2 distinct components with 1 dorsally and 1 inferiorly going between a bifurcated sciatic nerve. The bursal hypertrophy and scar bands were carefully and delicately excised by use of a rotary shaver, arthroscopic dissection scissors, and blunt probe. Fibrovascular scars were delicately cauterized by use of a radiofrequency probe with attention to the branches of the inferior gluteal artery lying in proximity to the piriformis muscle. The tendon can hide behind a very thin layer of muscle overlying the nerve, which was observed in the later cases. Large scar bands were present in 29 patients and extended all the way from the greater trochanter to the gluteus maximus onto the sciatic nerve and extended up to the greater sciatic notch. These scar bands were released so that the sciatic nerve had adequate excursion with internal (Fig 5A) and external (Fig 5B) rotation of the hip in flexion and extension. Pathologic characteristics of the gluteus maximus muscle included one of ropelike character and one of a subluxated gluteus maximus into a solitary scar band. In 3 patients the obturator internus muscle could be observed to be binding the sciatic nerve. In 2 patients the hamstring tendon insertion was thickened over the ischium and onto the sciatic nerve. There were no recognized complications associated with the endoscopic procedure at the time of this report.