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Deep gluteal syndrome: anatomy, imaging, and management of sciatic nerve entrapments in the subgluteal space. Skeletal Radiol. DOI 10.1007/s00256-015-2124-6

Authors:
  • Diagnóstico Médico Cantabria DMC
  • Diagnóstico Médico Cantabria DMC
  • Hospital Clinica Mompia
  • Diagnóstico Médico Cantabria DMC

Abstract

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 Bpiriformis 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/pseudotumors. 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.
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... Within this region, apart from the piriformis muscle, the superior and inferior gemellus muscle, the obturator internus muscle, and the quadratus femorus muscle also are located. 4,5 Clinical presentation of PS is often pain in the gluteal region, aggravated when in a seating position with the inability to sit for a longer period of time, with or without pain radiating to the posterior thigh. Sometimes paresthesia is present as well. ...
... [6][7][8] PS is often difficult to diagnose, as the clinical presentation is rather vague and most clinical symptoms overlap with lumbar and other intra-or extra-articular hip pathologies, and therefore it is still underdiagnosed. 5 Initial treatment for PS consists of physiotherapy regimens with stretching and muscle strengthening with or without an extra-articular injection with steroids or a local anesthetic. 2,5,9 A surgical decompression and release of the nerve is considered after a failed conservative therapy of at least 3 months. ...
... 5 Initial treatment for PS consists of physiotherapy regimens with stretching and muscle strengthening with or without an extra-articular injection with steroids or a local anesthetic. 2,5,9 A surgical decompression and release of the nerve is considered after a failed conservative therapy of at least 3 months. Both open and endoscopic techniques have been described. ...
Article
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Purpose To survey the clinical satisfaction of patients who have had an endoscopic piriformis release with a sciatic nerve neurolysis. Methods Patients with piriformis syndrome (PS) who were treated with an endoscopic piriformis release combined with a sciatic neurolysis between 2013 and 2018 were identified. All patients had a minimum follow-up of 1 year. Patients were contacted by telephone in 201,9 whereby the rate of satisfaction and pain were evaluated with the Benson surgery scale and the visual analog scale (VAS). Results The average duration of symptoms at first presentation was 34 months (range 16-54 months). Thirty-seven cases (82,2%) had an EMG that showed sciatic compression around the piriformis muscle. The average preoperative VAS pain score was 7.4 (± 0.8). The mean VAS score at the time of the survey was 1.9 (± 2.4). The difference in median preoperative and postoperative VAS was 6. Using the Wilcoxon signed-rank test, we found there was a significant improvement of VAS score (with P < .001). Using the Benson operative scale, we found that outcomes at the time of the survey were excellent in 23 patients (24 cases, 53.4%), good in 10 (22.2%), fair in 3 (6.7%), and poor in 8 (17.7%). Three patients with a poor result had a wrong diagnosis of PS and ended up needing treatment for a different diagnosis. In total, 33 patients answered affirmative on the question if they would undergo the procedure again. Apart from 3 local wound infections, no major complications were observed. Conclusions Once a diagnosis is made, the endoscopic release of the piriformis tendon results in significant improvement in Pain VAS scores for patients with refractory symptoms despite conservative treatment. Level of Evidence Level IV, therapeutic case series.
... DGS is a rare entity in primary care, sports medicine, and orthopedic clinics, with limited reports in relevant literature. However, patients with hip pain present to family medicine practices commonlyconsisting of an estimated 164 encounters per clinician per year, accounting for 0.61% of all office visits (2,3). The scarcity of reporting with DGS is possibly because of the lack of provider confidence in specific diagnosis and the lack of evidence supporting diagnostic imaging and procedures to appropriately identify pain generators in the posterior hip (4). ...
... While commonly attributed to the piriformis, posterior hip and buttock pain may arise from any of the deep gluteal structures. To date, specific reports of DGS in the orthopedic, radiology, and sports medicine literature have been limited and evidence for diagnostic tools have been lacking (2,4,7). The use of ultrasound is particularly subjective with regards to operator expertise and interpretation of pathology. ...
... Symptoms are usually unilateral and exacerbated by hip flexion, hip rotation, prolonged sitting, and physical activityhowever, bilateral cases may be encountered. Numbness and paresthesia of the affected lower extremity and buttock also may be present (2,6,(8)(9)(10). ...
Article
While buttock pain is a common complaint in sports medicine, deep gluteal syndrome (DGS) is a rare entity. DGS has been proposed as a unifying term referring to symptoms attributed to the various pain generators located in this region. While not all-inclusive, the diagnosis of DGS allows for focus on pathology of regionally associated muscles, tendons, and nerves in the clinical evaluation and management of posterior hip and buttock complaints. An understanding of the anatomic structures and their kinematic and topographic relationships in the deep gluteal space is pivotal in making accurate diagnoses and providing effective treatment. Because presenting clinical features may be unrevealing while imaging studies and diagnostic procedures lack supportive evidence, precise physical examination is essential in obtaining accurate diagnoses. Management of DGS involves focused rehabilitation with consideration of still clinically unproven adjunctive therapies, image-guided injections, and surgical intervention in refractory cases.
... Magnetic resonance imaging features of deep gluteal syndrome etiologic factors other than proximal hamstring tendinopathy and IF impingement (ie, fibrous and fibrovascular bands, piriformis syndrome, gemelli-obturator internus syndrome, and gluteal contacture) were also searched. 10,11 Statistical Analysis Data analysis was performed by using IBM SPSS Statistics 17.0 software (IBM Corporation). The distribution of continuous variables was determined with Shapiro-Wilk test. ...
... Except for 2 patients, the subjects in the symptomatic group did not have MRI features of deep gluteal syndrome etiologic factors other than proximal hamstring tendinopathy and/or IF impingement. 10,11 Both of the exceptional patients in this regard had mild unilateral (right-sided) hypertrophy of the piriformis, one with and one without MRI findings of ipsilateral IF impingement. ...
Article
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Objective: The purpose of this study was to propose and validate a novel physical examination test for ischiofemoral impingement with magnetic resonance imaging (MRI) correlation. Methods: We prospectively studied 24 women with buttock (deep gluteal) pain and 27 asymptomatic women. Each group underwent a 2-stage physical examination test that featured hip adduction-external rotation-extension and knee flexion. Visual analog scale pain scores were noted just before and during test stages on both sides. The MRI findings of the ischiofemoral impingement were evaluated quantitatively and qualitatively. Results: Mean ages were 56.0 and 55.2 years (P = 0.797), and mean body mass indexes were 29.1 and 28.8 kg/m2 (P = 0.817) in symptomatic and asymptomatic groups, respectively. Ischiofemoral spaces were significantly narrower (P < 0.001), ischial angles were wider (P < 0.001, right; P = 0.002, left), and soft tissue edema at the ischiofemoral space was more common (P < 0.001) in the symptomatic group, which also had higher pretest visual analog scale scores (P < 0.001) that increased significantly during both upright standing (P = 0.003, right; P < 0.001, left) and recumbent (P < 0.001 for both sides) stages of the physical examination test. Conclusions: A novel physical examination test significantly increases symptoms of ischiofemoral impingement with positive MRI correlation.
... Modern clinicians and researchers reserve the term sciatic neuritis for inflammatory disorders of the sciatic nerve trunk that are seen on imaging studies. Common examples include deep gluteal or piriformis syndromes, 64 and less common examples include sciatic nerve damage following hip 60 or low back surgery, 65 and tumors of the sciatic nerve. 66 Historically, the diagnosis of sciatic neuritis was much more common. ...
... 72 Newer research shows that those diagnosing sciatic neuritis were on the right track. Sciatic nerve trunk inflammation is present in disorders such as piriformis syndrome 64 and may be present in many more forms of sciatica. 1,61 Sciatic neuritis is not a disease on its own, but occurs secondary to other pathology. ...
Chapter
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• Common features of sciatica include mechanosensitivity, inflammation, and swelling along the sciatic nerve pathway • These occur in sciatic pain originating from within or outside the spine • Central or peripheral sensitization may explain these common features
... It is thought that trauma, fibrosis, anomalies, avulsions, tendinosis, strains, calcifications, or spasms of these muscles or their tendons contributes to the compression of the nerves. 351 Connective tissue of muscles forms an added sheath around the sciatic nerve. This fascial sheath around the sciatic nerve is called the epimysium and exists in the buttocks, for example between the gluteus maximus and quadratus femoris, and also lower in the thigh, between the hamstring muscles. ...
Chapter
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• Low back disorders are the most common cause of sciatica • Gluteal region disorders are the second most common cause of sciatica • Systemic illness such as autoimmune or vascular disease may contribute to sciatica • Patients may have more than one source of pain
... 31 As a result, posterior hip pain and sciatica frequently present diagnostic and therapeutic challenges, and a precise diagnostic tool is needed to focus the differentials. 32 Sciatic neuropathy has traditionally been diagnosed using a combination of clinical history, physical examination, and electrodiagnostic studies. 33 However, MRN is becoming increasingly popular in the assessment of sciatic neuropathy due to its multiple advantages, including assessment of nerve continuity, localization of injury or entrapment, and detection of secondary muscle denervation. ...
Article
Full-text available
Peripheral nerve injuries (PNIs) continue to present both diagnostic and treatment challenges. While nerve transections are typically a straightforward diagnosis, other types of PNIs, such as chronic or traumatic nerve compression, may be more difficult to evaluate due to their varied presentation and limitations of current diagnostic tools. As a result, diagnosis may be delayed, and these patients may go on to develop progressive symptoms, impeding normal activity. In the past, PNIs were diagnosed by history and clinical examination alone or techniques that raised concerns regarding accuracy, invasiveness, or operator dependency. Magnetic resonance neurography (MRN) has been increasingly utilized in clinical settings due to its ability to visualize complex nerve structures along their entire pathway and distinguish nerves from surrounding vasculature and tissue in a noninvasive manner. In this review, we discuss the clinical applications of MRN in the diagnosis, as well as pre- and postsurgical assessments of patients with peripheral neuropathies.
... [5,6] This syndrome is controversial. For its clinical diagnostic characteristics, some people say that it is underdiagnosed [7,8] and some people think that it is overdiagnosed. [9] Therefore, in this case, we need to clarify its main clinical features to improve the accuracy of clinical diagnosis. ...
Article
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Background: Piriformis syndrome (PS) is a condition in which the sciatic nerve is compressed when passing through the inferior mouth of the piriformis muscle, mainly caused by pain in one hip and leg. In severe cases, patients may experience severe buttock and lower limb pain, discomfort, difficulty walking, and claudication. It is estimated that the annual incidence of low back pain and sciatica is about 40 million cases, and the annual incidence of piriformis syndrome is about 2.4 million cases. The aim of this systematic review is to assess the effectiveness and safety of Little needle-scalpel therapy for Piriformis syndrome. Methods: Two reviewers will electronically search the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; China National Knowledge Infrastructure (CNKI); Chinese Biomedical Literature Database (CBM); Chinese Scientific Journal Database (VIP database); and Wan-Fang Database from the inception, without restriction of publication status and languages. Additional searching including researches in progress, the reference lists, and the citation lists of identified publications. Study selection, data extraction, and assessment of study quality will be performed independently by 2 reviewers. If it is appropriate for a meta-analysis, RevMan 5.4 statistical software will be used; otherwise, a descriptive analysis will be conducted. Data will be synthesized by either the fixed-effects or random-effects model according to a heterogeneity test. The results will be presented as risk ratio (RR) with 95% confidence intervals (CIs) for dichotomous data and weight mean difference (WMD) or standard mean difference (SMD) 95% CIs for continuous data. Results: This study will provide a comprehensive review of the available evidence for the treatment of Little needle-scalpel with piriformis syndrome. Conclusions: The conclusions of our study will provide an evidence to judge whether Little needle-scalpel is an effective and safe intervention for patients with piriformis syndrome. Ethics and dissemination: This systematic review will be disseminated in a peer-reviewed journal or presented at relevant conferences. It is not necessary for a formal ethical approval because the data are not individualized. Trial registration number: INPLASY2020110092.
... Arthroscopic treatment of DGS has shown similar results to open surgery in clinical series. It also has a lower rate of complications (Hernando et al., 2015). ...
Article
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To determine the morphometric landmarks and anatomical variants relevant to the arthroscopic approach to the deep gluteal space. Twenty deep gluteal spaces from cadaveric specimens were dissected. The anatomical variants of the sciatic nerve (SN) were determined according to the Beaton and Anson classification. A morphometric study of the distances in the subgluteal space was carried out to define the anatomical references to achieve a safe arthroscopic approach for piriformis syndrome [GT-SN=Distance from greater trochanter (GT) to SN emergence; GT-IT=Distance from GT to ischial tuberosity (IT); GT-IGA=distance from GT to inferior gluteal artery (IGA) emergence; IT-SN=distance from IT to SN emergence; IT-IGA=distance from IT to IGA]. The SN showed the most frequent anatomical pattern with an undivided nerve coming out of the pelvis below the piriformis muscle (Beaton type A) in 16 specimens (80 %). The common peroneal nerve emergence in the subgluteal space through the piriformis muscle (PM) with the tibial nerve being located at the lower margin of the piriformis muscle (Beaton type B) was observed in 4 specimens (20 %). The morphometric measurements of the surgical area of study were: GT-SN=7.23 cm (±8.3); GT-IT=8.56 cm (±0.1); GT-IGA=8.46 cm (±0.97); IT-SN=5.28 cm (±0.73), IT-IGA=5.47 cm (±0.74). When planning surgery for the deep gluteal syndrome in adult patients, the fact that the emergence of the SN in the subgluteal space is approximately 7 cm from the greater trochanter and 5 cm from the ischial tuberosity must be considered.
... Arthroscopic treatment of DGS has shown similar results to open surgery in clinical series. It also has a lower rate of complications (Hernando et al., 2015). ...
Article
Full-text available
CAPURRO, B.; TEY, M.; MONLLAU, J. C.; CARRERA, A.; MARQUES, F. & REINA, F. Anatomic landmarks for a safe arthroscopic approach to the deep gluteal space: A cadaveric study. Int. J. Morphol., 39(2):359-365, 2021. SUMMARY: To determine the morphometric landmarks and anatomical variants relevant to the arthroscopic approach to the deep gluteal space. Twenty deep gluteal spaces from cadaveric specimens were dissected. The anatomical variants of the sciatic nerve (SN) were determined according to the Beaton and Anson classification. A morphometric study of the distances in the subgluteal space was carried out to define the anatomical references to achieve a safe arthroscopic approach for piriformis syndrome [GT-SN=Distance from greater trochanter (GT) to SN emergence; GT-IT=Distance from GT to ischial tuberosity (IT); GT-IGA=distance from GT to inferior gluteal artery (IGA) emergence; IT-SN=distance from IT to SN emergence; IT-IGA=distance from IT to IGA]. The SN showed the most frequent anatomical pattern with an undivided nerve coming out of the pelvis below the piriformis muscle (Beaton type A) in 16 specimens (80 %). The common peroneal nerve emergence in the subgluteal space through the piriformis muscle (PM) with the tibial nerve being located at the lower margin of the piriformis muscle (Beaton type B) was observed in 4 specimens (20 %). The morphometric measurements of the surgical area of study were: GT-SN=7.23 cm (±8.3); GT-IT=8.56 cm (±0.1); GT-IGA=8.46 cm (±0.97); IT-SN=5.28 cm (±0.73), IT-IGA=5.47 cm (±0.74). When planning surgery for the deep gluteal syndrome in adult patients, the fact that the emergence of the SN in the subgluteal space is approximately 7 cm from the greater trochanter and 5 cm from the ischial tuberosity must be considered.
Chapter
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• Combinations of tests help rule the spine and nerve root involvement in or out • Deficits are more pronounced in those with radicular sciatica compared to extraspinal or myofascial sciatica • Red flag signs may prompt urgent or emergent referral
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Object: Extraspinal sciatica can present unique challenges in clinical diagnosis and management. In this study, the authors evaluated qualitative and quantitative patterns of sciatica-related pathology at the ischial tuberosity on MR neurography (MRN) studies performed for chronic extraspinal sciatica. Methods: Lumbosacral MRN studies obtained in 14 patients at the University of California, San Francisco between 2007 and 2011 were retrospectively reviewed. The patients had been referred by neurosurgeons or neurologists for chronic unilateral sciatica (≥ 3 months), and the MRN reports described asymmetrical increased T2 signal within the sciatic nerve at the level of the ischial tuberosity. MRN studies were also performed prospectively in 6 healthy volunteers. Sciatic nerve T2 signal intensity (SI) and cross-sectional area at the ischial tuberosity were calculated and compared between the 2 sides in all 20 subjects. The same measurements were also performed at the sciatic notch as an internal reference. Adjacent musculoskeletal pathology was compared between the 2 sides in all subjects. Results: Seven of the 9 patients for whom detailed histories were available had a specific history of injury or trauma near the proximal hamstring preceding the onset of sciatica. Eight of the 14 patients also demonstrated soft-tissue abnormalities adjacent to the proximal hamstring origin. The remaining 6 had normal muscles, tendons, and marrow in the region of the ischial tuberosity. There was a significant difference in sciatic nerve SI and size between the symptomatic and asymptomatic sides at the level of the ischial tuberosity, with a mean adjusted SI of 1.38 compared with 1.00 (p < 0.001) and a mean cross-sectional nerve area of 0.66 versus 0.54 cm(2) (p = 0.002). The control group demonstrated symmetrical adjusted SI and sciatic nerve size. Conclusions: This study suggests that chronic sciatic neuropathy can be seen at the ischial tuberosity in the setting of prior proximal hamstring tendon injury or adjacent soft-tissue abnormalities. Because hamstring tendon injury as a cause of chronic sciatica remains a diagnosis of exclusion, this distinct category of patients has not been described in the radiographic literature and merits special attention from clinicians and radiologists in the management of extraspinal sciatica. Magnetic resonance neurography is useful for evaluating chronic sciatic neuropathy both qualitatively and quantitatively, particularly in patients for whom electromyography and traditional MRI studies are unrevealing.
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Recent advances in magnetic resonance (MR) imaging have revolutionized peripheral nerve imaging and made high-resolution acquisitions a clinical reality. High-resolution dedicated MR neurography techniques can show pathologic changes within the peripheral nerves as well as elucidate the underlying disorder or cause. Neurogenic pain arising from the nerves of the pelvis and lumbosacral plexus poses a particular diagnostic challenge for the clinician and radiologist alike. This article reviews the advances in MR imaging that have allowed state-of-the-art high-resolution imaging to become a reality in clinical practice.
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To detect the variable relationship between sciatic nerve and piriformis muscle and make surgeons aware of certain anatomical features of each variation that may be useful for the surgical treatment of the piriformis syndrome. The gluteal region of 147 Caucasian cadavers (294 limbs) was dissected. The anatomical relationship between the sciatic nerve and the piriformis muscle was recorded and classified according to the Beaton and Anson classification. The literature was reviewed to summarize the incidence of each variation. The sciatic nerve and piriformis muscle relationship followed the typical anatomical pattern in 275 limbs (93.6 %). In 12 limbs (4.1 %) the common peroneal nerve passed through and the tibial nerve below a double piriformis. In one limb (0.3 %) the common peroneal nerve coursed superior and the tibial nerve below the piriformis. In one limb (0.3 %) both nerves penetrated the piriformis. In one limb (0.3 %) both nerves passed above the piriformis. Four limbs (1.4 %) presented non-classified anatomical variations. When a double piriformis muscle was present, two different arrangements of the two heads were observed. Anatomical variations of the sciatic nerve around the piriformis muscle were present in 6.4 % of the limbs examined. When dissection of the entire piriformis is necessary for adequate sciatic nerve decompression, the surgeon should explore for the possible existence of a second tendon, which may be found either inferior or deep to the first one. Some rare, unclassified variations of the sciatic nerve should be expected during surgical intervention of the region.
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With the expansion of endoscopically exploring various areas around the hip have come new areas to define. The area posterior to the hip joint, known as the subgluteal space or deep gluteal space (DGS), is one such area. This chapter will summarize the relevant anatomy and pathology commonly found in the DGS. It is hoped that this will allow the reader to further explore the area and treat the appropriate pathological areas.
Book
Hip pathology and nonarthritic hip conditions have only recently been recognized as a cause of hip pain. In 2003, Ganz, Leunig and colleagues described the concept of femoroacetabular impingement (FAI) as a cause of hip pain and a mechanism for end-stage hip osteoarthritis. Ganz et al. also postulated that 70-90% of hip osteoarthritis is likely due to abnormal hip mechanics related to FAI, dysplasia, or other hip deformities. Over the past ten years, the treatment of these non-arthritic hip pathologies has grown dramatically, and has been estimated to grow by 15% each year. It is the largest segment of grown in sports medicine and orthopedics as a whole. However, no definitive reference yet exists on hip arthroscopy and hip joint preservation surgery. While books have been published on hip arthroscopy, these texts are limited to the technical aspects of the procedure and do not explore content related to hip joint preservation surgery. The scope of this book covers the basic science of hip pathology, anatomy, biomechanics, pathology, and treatment. It has put together up-to-date research and has invited opinion leaders in the field to contribute to the text. The book is focused on disease pathology and provides comprehensive information on each disease topic, which is followed by technique-driven chapters to provide surgeons a reference for any procedure related to non-arthritic conditions of the hip.
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Purpose: To evaluate continuity of the sacrotuberous ligament (STL) in normal and abnormal hamstring (HS) tendons on magnetic resonance (MR) images and to test the hypothesis that greater degrees of HS retraction are correlated with STL discontinuity. Materials and methods: The institutional review board approved this retrospective HIPAA-compliant study and waived informed consent. Control cohort comprised 33 patients (mean age, 54.1 years) without HS abnormalities at hip MR arthrography. Study cohort comprised 100 patients (mean age, 55.3 years) with HS abnormalities at pelvic or hip MR imaging. Two musculoskeletal radiologists independently assessed STL continuity with the ischium and semimembranosus (SM) and conjoined biceps femoris and semitendinosus (BF-ST) tendons and evaluated these tendons for tendinopathy, partial tear, or rupture. A third musculoskeletal radiologist measured retraction of ruptured tendons. Inter- and intraobserver agreement was calculated with weighted κ or intraclass correlation coefficients. HS abnormalities in the cohorts were compared with Mann-Whitney test. In patients with tendon rupture, relationships between qualitative (STL and HS attachments) and quantitative (tendon retraction measurements) data were analyzed with analysis of variance and linear regression with Bonferroni correction. Results: STL was continuous with ischium in all patients. In control patients, STL was always continuous with BF-ST but never continuous with SM. In study patients, BF-ST tendon alone, SM tendon alone, and both BF-ST and SM tendons showed abnormalities in 17, six, and 77 patients, respectively. HS rupture occurred in 24 patients; it involved BF-ST tendon alone in 13 patients and both BF-ST and SM tendons in 11. STL was continuous with BF-ST tendon in 12 patients and discontinuous in 12 patients. Retraction of BF-ST tendon (mean, 33 mm; range, 5-81 mm) was independently correlated with STL continuity with BF-ST (P = .0001) and SM (P = .0004) tendon rupture. Retraction was significantly greater (P ≤ 0.01) when STL was discontinuous and SM tendon was ruptured. Inter- and intraobserver agreement was very good or excellent in categorization of HS abnormalities and measurement of retraction. Conclusion: STL showed continuity with both ischium and BF-ST tendon but not SM tendon. In HS rupture, tendon retraction was significantly less when STL remained attached to BF-ST tendon.
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The purpose of this study was to determine the diagnostic accuracy of the straight leg raise (SLR), active piriformis, and seated piriformis stretch tests in identifying individuals with sciatic nerve entrapment. Thirty-three individuals (female = 25 and male = 8) with a mean age of 43 years (range 15-64; SD ± 11 years) were included in the study. Twenty-three subjects had endoscopic findings of sciatic nerve entrapment. Ten subjects without entrapment during endoscopic assessment were used as a control group. The results of the SLR, active piriformis, and seated piriformis stretch tests were retrospectively reviewed for each subject and compared between both groups. The accuracy of these tests for the endoscopic finding of sciatic nerve entrapment was determined by calculating the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio. The SLR had sensitivity of 0.15, specificity of 0.95, positive likelihood ratio of 3.20, negative likelihood ratio of 0.90, and diagnostic odds ratio of 3.59. The active piriformis test had sensitivity of 0.78, specificity of 0.80, positive likelihood ratio of 3.90, negative likelihood ratio of 0.27, and diagnostic odds ratio of 14.40. The seated piriformis stretch test had sensitivity of 0.52, specificity of 0.90, positive likelihood ratio of 5.22, negative likelihood ratio of 0.53, and diagnostic odds ratio of 9.82. The most accurate findings were obtained when the results of the active piriformis test and seated piriformis stretch test were combined, with sensitivity of 0.91, specificity of 0.80, positive likelihood ratio of 4.57, negative likelihood ratio of 0.11, and diagnostic odds ratio of 42.00. The active piriformis and seated piriformis stretch tests can be used to help identify patients with and without sciatic nerve entrapment in the deep gluteal region. LEVEL OF EVIDENCE: II.