Posterior hip endoscopy for deep gluteal syndrome associated with congenital malformation of the short external rotators: a case report

Deep gluteal syndrome (DGS) is an uncommon cause of buttock and posterior hip pain resulting from non-discogenic entrapment or irritation of neural structures within the deep gluteal space. Differential diagnoses of posterior hip pain include piriformis syndrome, ischiofemoral impingement, and proximal hamstring tendon pathology. Most reported cases of DGS are related to piriformis hypertrophy or fibrovascular bands, whereas congenital malformations of the short external rotators are rarely described. We report the case of a young female patient with debilitating buttock and posterior thigh pain caused by an unusual combination of obturator internus hypertrophy, piriformis hypoplasia, and complete agenesis of the quadratus femoris. Magnetic resonance imaging demonstrated an abnormal course of the sciatic nerve within the deep gluteal space. A fully endoscopic posterior hip release was performed, consisting of selective longitudinal tenotomy of the hypertrophic conjoint tendon formed by the obturator internus and gemelli muscles and combined external and internal neurolysis of the sciatic nerve, addressing dynamic neural irritation rather than fixed compressive pathology, with careful preservation of the medial femoral circumflex artery (MFCA). Postoperatively, the patient experienced complete pain relief and returned to normal daily activities within 12 weeks, maintaining full recovery at 2-year follow-up. This case highlights that congenital muscular anomalies may underlie DGS and demonstrates that posterior hip endoscopy allows safe and effective treatment of dynamic neural irritation while preserving critical vascular structures.