Evaluation and management of ischiofemoral impingement: a pathophysiologic, radiologic, and therapeutic approach to a complex diagnosis.

Ischiofemoral impingement syndrome (IFI) is an underrecognized form of atypical, extra-articular hip impingement defined by hip pain related to narrowing of the space between the ischial tuberosity and the femur. The etiology of IFI is multifactorial and potential sources of ischiofemoral engagement include anatomic variants of the proximal femur or pelvis, functional disorders as hip instability, pelvic/spinal instability, or abductor/adductor imbalance, ischial tuberosity enthesopathies, trauma/overuse or extreme hip motion, iatrogenic conditions, tumors and other pathologies. Magnetic resonance imaging (MRI) is the diagnostic procedure of choice for assessing IFI and may substantially influence patient management. The injection test of the ischiofemoral space (IFS) has both a diagnostic and therapeutic function. Endoscopic decompression of the IFS appears useful in improving function and diminishing hip pain in patients with IFI but conservative treatment is always the first step in the treatment algorithm. Because of the ever-increasing use of advanced MRI techniques, the frequent response to conservative treatment, and the excellent outcomes of new endoscopic treatment, radiologists must be aware of factors that predispose or cause IFI. In addition, focused treatment in these conditions is often more important than in secondary impingement. In this article, we briefly describe the anatomy of the IFS, review the clinical examination and symptoms, assess the diagnostic imaging criteria and pathophysiological mechanisms, and develop an understandable classification of IFI, with particular focus on its etiology, predisposing factors, and associated musculoskeletal abnormalities. We also assess the role of the radiologist in the diagnosis, treatment, and preoperative evaluation of both primary and secondary IFI.

Deep gluteal space problems: piriformis syndrome, ischiofemoral impingement and sciatic nerve release.

BACKGROUND: Deep gluteal syndrome (DGS) is an underdiagnosed entity characterized by pain and/or dysesthesias in the buttock area, hip or posterior thigh and/or radicular pain due to a non-discogenic sciatic nerve entrapment in the subgluteal space. Multiple pathologies have been incorporated in this all-included "piriformis syndrome", a term that has nothing to do with the presence of fibrous bands, obturator internus/gemellus syndrome, quadratus femoris/ischiofemoral pathology, hamstring conditions, gluteal disorders and orthopedic causes. METHODS: This article describes the subgluteal space anatomy, reviews known and new etiologies of DGS, and assesses the role of the radiologist and orthopaedic surgeons in the diagnosis, treatment and postoperative evaluation of sciatic nerve entrapments. CONCLUSION: DGS is an under-recognized and multifactorial pathology. The development of periarticular hip endoscopy has led to an understanding of the pathophysiological mechanisms underlying piriformis syndrome, which has supported its further classification. The whole sciatic nerve trajectory in the deep gluteal space can be addressed by an endoscopic surgical technique. Endoscopic decompression of the sciatic nerve appears useful in improving function and diminishing hip pain in sciatic nerve entrapments, but requires significant experience and familiarity with the gross and endoscopic anatomy. LEVEL OF EVIDENCE: IV.

Deep gluteal syndrome: anatomy, imaging, and management of sciatic nerve entrapments in the subgluteal space.

Deep gluteal syndrome (DGS) is an underdiagnosed entity characterized by pain and/or dysesthesias in the buttock area, hip or posterior thigh and/or radicular pain due to a non-discogenic sciatic nerve entrapment in the subgluteal space. Multiple pathologies have been incorporated in this all-included "piriformis syndrome," a term that has nothing to do with the presence of fibrous bands, obturator internus/gemellus syndrome, quadratus femoris/ischiofemoral pathology, hamstring conditions, gluteal disorders and orthopedic causes. The concept of fibrous bands playing a role in causing symptoms related to sciatic nerve mobility and entrapment represents a radical change in the current diagnosis of and therapeutic approach to DGS. The development of periarticular hip endoscopy has led to an understanding of the pathophysiological mechanisms underlying piriformis syndrome, which has supported its further classification. A broad spectrum of known pathologies may be located nonspecifically in the subgluteal space and can therefore also trigger DGS. These can be classified as traumatic, iatrogenic, inflammatory/infectious, vascular, gynecologic and tumors/pseudo-tumors. Because of the ever-increasing use of advanced magnetic resonance neurography (MRN) techniques and the excellent outcomes of the new endoscopic treatment, radiologists must be aware of the anatomy and pathologic conditions of this space. MR imaging is the diagnostic procedure of choice for assessing DGS and may substantially influence the management of these patients. The infiltration test not only has a high diagnostic but also a therapeutic value. This article describes the subgluteal space anatomy, reviews known and new etiologies of DGS, and assesses the role of the radiologist in the diagnosis, treatment and postoperative evaluation of sciatic nerve entrapments, with emphasis on MR imaging and endoscopic correlation.