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

Standardized measurement of the piriformis muscle and the proximal portion of the sacral nerve roots using transvaginal ultrasound

To identify the sonomorphological appearance and to measure the thickness of the piriformis muscle (PM) and the proximal portion of the sacral nerve roots S1-S3 in healthy premenopausal women.This prospective multicentric observational study included a consecutive series of women undergoing transvaginal sonography (TVS) at 2 tertiary gynecological referral centers. Standardized assessment of the pelvic organs was performed, followed by an attempt to visualize the right and left PM and sacral nerve roots S1-S3 at their origin in proximity to the sacral neuroforamen. Visualization rates, diameters of the muscle and nerve thickness, and the time needed to identify the PM were recorded.305 patients were included in the study. In 293 women (96.1%), the PM was identified bilaterally. The median diameter of the PM was 18.3mm on the right side and 18.4mm on the left side. S1 nerve roots were successfully identified bilaterally in 224 (73.4%) patients. Their right and left median diameters were 4.8mm. Both S2 nerves were successfully identified in 215 (70.5%) patients. Their median diameter were 4.3mm on both sides. S3 nerve roots were successfully identified in 203 (66.6%) patients. Their median diameter were 3.2mm on both sides.We describe methods which allow consistent and rapid identification of the PM and the S1-S3 sacral nerve roots using TVS. Visualization of the PM and the proximal portion of the sacral plexus may be useful regarding identification of pathological changes in PM thickness and could help to distinguish perineural cysts from other gynecological pathologies.

MR Imaging of Entrapment Neuropathies of the Hip

Entrapment neuropathies of the hip (ENH) can occur due to a variety of causes with clinical symptoms that may mimic musculoskeletal disorders. Etiologies include entrapment in a fibromuscular canal, tethering due to posttraumatic fibrosis and extrinsic compression from muscle hypertrophy or a mass. Magnetic resonance (MR) imaging enables detection and characterization of peripheral nerve pathology. In addition, MR imaging can impact both diagnostic judgment as well as therapeutic management (nonoperative and operative management) of patients with ENH. This review article will summarize the role of MR imaging in detection, characterization, and management of nerve entrapments around the hip joint.

Sciatic nerve entrapment after total hip arthroplasty in a patient with diffuse lipomatosis and developmental dysplasia of the hip: A rare case report

INTRODUCTION AND IMPORTANCE

Diffuse lipomatosis is rare. In this case, a patient with diffuse lipomatosis and developmental dysplasia of the hip (DDH) underwent total hip arthroplasty (THA). Postoperatively, the patient experienced sciatic nerve entrapment. The lack of treatment experience and related literature makes addressing this complication challenging.

CASE PRESENTATION

A 26-year-old female patient presented to our clinic with developmental dysplasia of the right hip and lower limb malformations. She underwent THA and, one week later, developed contralateral sciatic nerve entrapment, for which she received neurolysis. The patient was diagnosed with diffuse lipomatosis based on pathological results. Four years post-operation, she lives independently and is satisfied with the treatment outcomes.

CLINICAL DISCUSSION

This case report aims to illuminate the approach to diagnosing and treating patients with diffuse lipomatosis and DDH. By exploring the elements of this patient's journey to diagnosis and treatment, we aspire to aid future clinicians in navigating the challenges of performing THA for patients with anatomical abnormalities around the hip joint. Once neurological symptoms appear, sciatic nerve entrapment must be considered.

CONCLUSION

Neurological symptoms in the lower limbs following THA in patients with diffuse lipomatosis should prompt consideration of sciatic nerve entrapment. Adjustments in body positioning may be an effective method to prevent nerve entrapment in these patients. Once sciatic nerve entrapment is diagnosed, early surgery neurolysis may reduce the occurrence of sequelae.

Endoscopic Technique: Sciatic Neurolysis and Piriformis Tendon Release for Treating Piriformis Syndrome

Piriformis syndrome (PS) is an underdiagnosed condition, caused by entrapment of the sciatic nerve by the piriformis muscle tendon and adhesions in the deep gluteal space. We present a step-by-step endoscopic technique with the patient in a prone position through a posterior approach. This approach provides improved orientation for tracking the sciatic nerve from distal to proximal, facilitating the release of all adhesions and concluding with a piriformis tendon release. This method aims to enhance surgical safety during the procedure.

Endoscopic Treatment of Deep Gluteal Syndrome: 3-Portal Technique

We describe all-endoscopic deep gluteal syndrome treatment and sciatic nerve decompression at the infrapiriformis space. Surgery is performed with the patient in the prone position with the usual arthroscopic instruments and pump. The first step includes performing placement of 2 initial portals (medial and median) without fluoroscopy in the area of the ischial tuberosity and conjoint tendon, as well as release in this area with a subsequent shift in the lateral direction. The second step includes performing placement of an additional lateral portal for instruments, switching the camera into the median portal, and visualizing the sciatic nerve and its decompression at the infrapiriformis space and upper part of the thigh area. The postoperative period includes early activation, immediate passive and active motion after surgery, and full weight bearing the day after surgery.

Advances in Imaging of Compressive Neuropathies

Ultrasound and magnetic resonance neurography are useful modalities to aid in the assessment of compressive neuropathies, although they are still limited in their resolution of nerve microstructure and their capacity to monitor postoperative nerve recovery. Optical coherence tomography, a preclinical imaging modality, is promising in its ability to better identify structural and potential physiologic changes to peripheral nerves, but requires additional testing and research prior to widespread clinical implementation. Further advances in nerve imaging may elucidate the ability to visualize the zone of nerve injury intraoperatively, monitor the progression of nerve regeneration, and localize problems during nerve recovery.

Anatomical Proximity Between Sciatic Nerve and Ischial Spine and its Relationship to the Development of Deep Gluteal Pain Syndrome

OBJECTIVE

Deep gluteal syndrome (DGS) is a medical diagnosis in which the pathoanatomy of the subgluteal space contributes to pain. The growing recognition that gluteal neuropathies can be associated with the presence of a bone-neural conflict with irritation or compression may allow us to shed some light on this pathology. This study aims to determine whether the location of the sciatic nerve (SN) in relation to the ischial spine (IS) contributes to the development of DGS.

METHODS

The SN - IS relationship was analyzed based on magnetic resonance imaging (MRI) in 15 surgical patients (SPs), who underwent piriformis release, and in 30 control patients who underwent MRI of the pelvis for reasons unrelated to sciatica. The SN exit from the greater sciatic foramen was classified as either zone A (medial to the IS); zone B (on the IS); or zone C (lateral to the IS).

RESULTS

The SN was significantly closer to the IS in SPs than in MRI controls (P = 0.014). When analyzing patients of similar age, SNs in SPs were significantly closer (P = 0.0061) to the IS, and located in zone B significantly more (P = 0.0216) as compared to MRI controls. Patients who underwent surgery for piriformis release showed a significant decrease in pain postoperatively (P < 0.0001).

CONCLUSIONS

The results from this study suggest that the relationship between the IS and SN may play a role in the development of DGS. This may also help establish which patients would benefit more from surgical intervention.

Ultrasound-Guided Sciatic Nerve Hydrodissection Can Improve the Clinical Outcomes of Patients with Deep Gluteal Syndrome: A Case-Series Study

Deep gluteal syndrome (DGS) is caused by sciatic nerve entrapment. Because fascial entrapment neuropathies may occur in multiple locations, ultrasound-guided nerve hydrodissection is a key component of DGS treatment. In this study, we examined the clinical outcomes of patients with DGS undergoing ultrasound-guided sciatic nerve hydrodissection. A 10 mL mixture consisting of 5% dextrose, 0.2% lidocaine (Xylocaine), and 4 mg betamethasone (Rinderon) was used for nerve hydrodissection. Clinical outcomes were evaluated using Numeric Rating Scale (NRS) scores of pain, the proportion of patients with favorable outcomes (reduction of ≥50% in pain), the duration for which patients exhibited favorable outcomes (percentage of follow-up duration), and the occurrence of major complications and minor side effects. A total of 53 patients were consecutively included and followed up for 3 to 19 months. After the initial injection, the NRS scores significantly improved at 1 week, 1 month, 3 months, and the final follow-up. Specifically, 73.6%, 71.7%, 64.2%, and 62.3% of the patients exhibited favorable outcomes at 1 week, 1 month, 3 months, and the final follow-up, respectively. The median duration for which the patients exhibited favorable outcomes was 84.7% of the follow-up period. Three patients (5.7%) experienced transient dizziness and vomiting, which resolved without further treatment. No vessel or nerve puncture was observed. Overall, ultrasound-guided sciatic nerve hydrodissection is a safe procedure that mitigates the pain associated with DGS. To achieve favorable outcomes, three consecutive injections 3 weeks apart are required.

Unrepaired Trochanteric Bursae as a Risk Factor for Deep Gluteal Syndrome After Total Hip Arthroplasty: A Prospective Randomized Controlled Trial

BACKGROUND

The trochanteric bursae are often left unrepaired after total hip arthroplasty (THA) and they retract posteriorly over the muscle belly of the piriformis. Deep gluteal syndrome (DGS) is a multifactorial condition presenting as buttock pain and is attributed to nondiscogenic sciatic nerve irritation or impingement causes. The purpose of this study was to investigate the relationship between bursal repair and incidence of DGS in patients undergoing THA.

METHODS

This prospective randomized trial included patients treated with a THA between January and December 2022 for a diagnosis of primary osteoarthritis. Patients were randomized into 2 groups: group 1 underwent a routine bursal repair, while group 2 did not, leaving the bursae unrepaired. Follow-up was performed on the 15th, 30th, and 90th day postoperatively with clinical scores, physical examinations, and laboratory tests. In this cohort of 104 patients, mean age was 55 years (range, 26 to 88). Demographic variables as well as range of motion and overall clinical results showed no significant difference between the groups.

RESULTS

DGS rates were significantly more common in the patients who had an unrepaired bursa (group 2) both on the 30th and 90th postoperative days, while comparison of lateral trochanteric pain on palpation showed similar results between the groups.

CONCLUSIONS

DGS is common in individuals who have unrepaired trochanteric bursal tissue following a THA. Despite its higher frequency, these symptoms did not have a substantial impact on the overall clinical scores, which remained consistent across the study groups.

Importance of Sacrotuberous Ligament in Transgluteal Approach for Sciatic Nerve Entrapment in the Greater Sciatic Notch (Piriformis Syndrome)

OBJECTIVE

The efficacy of sciatic nerve decompression via transgluteal approach for entrapment of the sciatic nerve at the greater sciatic notch, called piriformis syndrome, and factors affecting the surgical outcome were analyzed.

METHODS

The outcome of pain reduction was analyzed in 81 patients with sciatic nerve entrapment who underwent decompression through a transgluteal approach. The patients were followed up for at least 6 months. The degree of pain reduction was analyzed using a numerical rating scale-11 (NRS-11) score and percent pain relief before and after last follow-up following surgery. Success was defined by at least 50% reduction in pain measured via NRS-11. To assess the degree of subjective satisfaction, a 10-point Likert scale was used. In addition, demographic characteristics, anatomical variations, and variations in surgical technique involving sacrotuberous ligamentectomy were analyzed as factors that affect the surgical outcome.

RESULTS

At a follow-up of 17.5±12.5 months, sciatic nerve decompression was successful in 50 of 81 patients (61.7%), and the pain relief rate was 43.9±34.17. Subjective improvement based on a 10-point Likert scale was 4.90±3.43. Among the factors that affect the surgical outcome, only additional division of the sacrotuberous ligament during piriformis muscle resection played a significant role. The success rate was higher in the scarotuberous ligementectomy group (79.4%) than in the non-resection group (42.6%), resulting in statistically significant difference based on average NRS-11 score, percent pain relief, and subjective improvement (p<0.05, independent t-test).

CONCLUSION

Sciatic nerve decompression is effective in pain relief in chronic sciatica due to sciatic nerve entrapment at the greater sciatic notch. Its effect was further enhanced by circumferential dissection of the sciatic nerve based on the compartment formed by the piriformis muscle and the sacrotuberous ligament in the greater sciatic notch.

Ischiofemoral impingement syndrome: A five-case series report

Gluteal pain is a frequent cause of medical attention in the daily clinical practice. It can be caused by multiple pathologies, being ischiofemoral impingement syndrome among those included in its differential diagnosis. Encompassed within the deep gluteal syndromes, this entity occurs as a consequence of the entrapment of the neuromuscular structures between the lesser femoral trochanter and the ischial tuberosity, causing pain in the root of the lower limb, with irradiation towards the thigh or the gluteal region and poor tolerance to deambulation and sedestation. The magnetic resonance imaging of the hip is fundamental for its diagnosis, and its management consists on medical treatment at onset. Despite not being a frequent diagnosis in the clinical practice in Rheumatology, keeping it in mind helps improving its prognosis by establishing an early and adequate treatment.

Anatomical Relationships of the Sciatic Nerve and Pudendal Nerve to the Ischial Spine as They Exit the Greater Sciatic Foramen

OBJECTIVE

Deep gluteal syndrome is a clinical condition in which discomfort may arise due to the pathoanatomy of the subgluteal space. We conducted an anatomical exploration to categorize the relationship of the piriformis muscle, sciatic nerve (SN), and pudendal nerve (PN) to the ischial spine (IS) and sacrospinous ligament.

METHODS

We analyzed 22 cadavers. The piriformis muscle, SN, and PN were exposed through either a transgluteal approach or a gluteal flap. The relationship of the neural structures to the IS, sacrospinous ligament, and ischial bone as they exit the greater sciatic foramen was observed, and the exit zones were classified as zone A, medial to the IS (entirely on sacrospinous ligament); zone B, on the IS; and zone C, lateral to the IS (entirely on ischial bone).

RESULTS

The SN was observed either in zone B or zone C in all specimens. The PN was found to be in either zone A or zone B in 97.6% of specimens. The most common combinations were SN in zone B and PN in zone A (type I), and SN in zone C and PN in zone B (type II).

CONCLUSIONS

The results from this study show clear anatomical differences in the SN-PN relationship, which may play a role in pain seen in deep gluteal syndrome. Moreover, classification of the SN-IS and PN-IS relationships described in this article will help describe different pathologies affecting the deep gluteal area.

Piriformis syndrome

Piriformis syndrome is a condition that is proposed to result from compression of the sciatic nerve, either in whole or in part, in the deep gluteal space by the piriformis muscle. The prevalence of piriformis syndrome depends upon the diagnostic criteria being used and the population studied but is estimated by some to be 5%-6% in all cases of low back, buttock, and leg pain and up to 17% of patients with chronic low back pain. While the sciatic nerve may pierce the piriformis muscle in about 16% of healthy individuals, this frequency is no different in those with the syndrome; thus, the relationship to this anatomic finding is unclear. The most common symptoms are buttock pain, external tenderness over the greater sciatic notch, and aggravation of the pain through sitting. Many clinical signs are reported for piriformis syndrome, but the sensitivity and specificity are unclear, in part because of the lack of a uniformly accepted case definition. In the majority of cases in the literature, it appears that the diagnosis is more ascribed to a myofascial condition rather than a focal neuropathy. Electrodiagnostic studies can be useful to exclude other causes of symptoms, but there is no well-accepted test to confirm the presence of piriformis syndrome. Ultrasound imaging may show thickening of the piriformis muscle, but further research is required to confirm that this is correlated with the clinical diagnosis. Magnetic resonance imaging and neurography may hold promise in the future, but there are not yet sufficient data to support adopting these methods as a standard diagnostic tool. The initial treatment of piriformis syndrome is typically conservative management with the general rehabilitation principles similar to other soft tissue musculoskeletal conditions. Local anesthetic, botulinum toxin, and/or corticosteroid injections have been reported by some to be beneficial for diagnostic or treatment purposes. Surgical interventions have also been used with variable success.

Diagnostic Approach to Lower Limb Entrapment Neuropathies: A Narrative Literature Review

Entrapment neuropathies of the lower limb are a misunderstood and underdiagnosed group of disorders, characterized by pain and dysesthesia, muscular weakness, and specific provoking movements on physical examination. The most frequent of these syndromes encountered in clinical practice are fibular nerve entrapment, proximal tibial neuropathy, sural nerve neuropathy, deep gluteal syndrome or sciatic nerve entrapment, and lateral femoral cutaneous nerve entrapment, also known as meralgia paresthetica. These are commonly mistaken for lumbar plexopathies, radiculopathies, and musculotendinous diseases, which appear even more frequently and have overlapping clinical presentations. A comprehensive anamnesis, physical examination, and electrodiagnostic studies should help clarify the diagnosis. If the diagnosis is still unclear or a secondary cause of entrapment is suspected, magnetic resonance neurography, MRI, or ultrasonography should be conducted to clarify the etiology, rule out other diseases, and confirm the diagnosis. The aim of this narrative review was to help clinicians gain familiarity with this disease, with an increase in diagnostic confidence, leading to early diagnosis of nerve damage and prevention of muscle atrophy. We reviewed the epidemiology, anatomy, pathophysiology, etiology, clinical presentation, and EDX technique and interpretation of the entrapment neuropathies of the lower limb, using articles published from 1970 to 2022 included in the Pubmed, MEDLINE, Cochrane Library, Google Scholar, EMBASE, Web of Science, and Scopus databases.

Cadaveric Study for Safe Elevation of a Profunda Artery Perforator Flap: Anatomy of the Perforators and Obturator Nerves

BACKGROUND

 This cadaveric study aimed to describe the anatomy of the profunda artery perforators (PAPs).

METHODS

 In total, nine free cadavers with 18 upper thighs were dissected, 12 of which were from female cadavers, and 6 were from male cadavers. The average age of the cadavers was 84.7 ± 4.2 years. Dissection was performed to evaluate the anatomic position and characteristics of the femoral PAPs. The perforator distance from the gluteal sulcus, number of perforators, perforating muscles, diameter of the perforators, origin of the perforators, and number of nerves passing above and below the perforators were determined.

RESULTS

 The average number of perforators that penetrate the adductor magnus muscle was 2.5. The average distance from the origin of the perforators to the gluteal sulcus was 71.72 ± 28.23 mm. The average numbers of the obturator nerves passing above and below the perforator in the adductor magnus muscle were 1.3 (range, 0-4) and 0.7 (range, 0-2), respectively.

CONCLUSION

 The results provide a detailed anatomic basis for the PAP flap. The perforators of a PAP flap may be included in a flap with a transverse design. Sacrificing the small obturator nerves during dissection may not lead to significant donor site morbidity.

An Updated Review of Magnetic Resonance Neurography for Plexus Imaging

Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial and lumbosacral plexi are challenging because of the anatomical complexity and technical limitations. The purpose of this article was to review the clinical context of MRN, describe advanced magnetic resonance (MR) techniques for plexus imaging, and list the general categories of utility of MRN with pertinent imaging examples. The selection and optimization of MR sequences are centered on the homogeneous suppression of fat and blood vessels while enhancing the visibility of the plexus and its branches. Standard 2D fast spin-echo sequences are essential to assess morphology and signal intensity of nerves. Moreover, nerve-selective 3D isotropic images allow improved visualization of nerves and multiplanar reconstruction along their course. Diffusion-weighted and diffusion-tensor images offer microscopic and functional insights into peripheral nerves. The interpretation of MRN in the brachial and lumbosacral plexi should be based on a thorough understanding of their anatomy and pathophysiology. Anatomical landmarks assist in identifying brachial and lumbosacral plexus components of interest. Thus, understanding the varying patterns of nerve abnormalities facilitates the interpretation of aberrant findings.

Ultrasound Imaging of the Sciatic Nerve

The sciatic nerve (SN) is the biggest nerve in the human body and innervates a large skin surface of the lower limb and several muscles of the thigh, leg, and foot. It originates from the ventral rami of spinal nerves L4 through S3 and contains fibers from both the posterior and anterior divisions of the lumbosacral plexus. After leaving the neural foramina, the nerve roots merge with each other forming a single peripheral nerve that travels within the pelvis and thigh. Non-discogenic pathologies of the SN are largely underdiagnosed entities due to nonspecific clinical tests and poorly described imaging findings. Likewise, to the best of our knowledge, a step-by-step ultrasound protocol to assess the SN is lacking in the pertinent literature. In this sense, the aim of the present manuscript is to describe the normal sono-anatomy of the SN from the greater sciatic foramen to the proximal thigh proposing a standardized and simple sonographic protocol. Then, based on the clinical experience of the authors, a few tips and tricks have been reported to avoid misinterpretation of confounding sonographic findings. Last but not least, we report some common pathological conditions encountered in daily practice with the main purpose of making physicians more confident regarding the sonographic "navigation" of a complex anatomical site and optimizing the diagnosis and management of non-discogenic neuropathies of the SN.

Arthroscopic treatment of deep gluteal syndrome and the application value of high-frequency ultrasound

PURPOSE

This study aimed to evaluate the efficacy of arthroscopic sciatic neurolysis for treating deep gluteal syndrome (DGS) and to analyse the application value of high-frequency ultrasound during perioperative period.

METHODS

Between June 2020 and February 2022, 30 patients with DGS who underwent failed conservative treatment were retrospectively analysed. Lateral arthroscopic exploration of the deep gluteal space and sciatic neurolysis were performed. In addition to pelvic X-ray, lumbar disc and hip magnetic resonance imaging (MRI), ultrasonography of the sciatic nerve was also performed in all patients. The visual analogue scale pain score (VAS), modified Harris hip score (mHHS) and Benson symptom-rating scale were used to evaluate the clinical efficacy. The correlation between preoperative sciatic nerve ultrasound and arthroscopic findings was analysed.

RESULTS

The median follow-up for these patients was 13 months (range,12-21 months). Preoperative ultrasonography showed precise morphological changes in 26 sciatic nerves of patients. The VAS score decreased from 5.0 (4.0, 6.0) preoperatively to 0.5 (0, 1.0) postoperatively (p < 0.001), and the mHHS increased from 64.0 (57.0, 67.0) preoperatively to 95.0 (93.0, 97.0) postoperatively (p < 0.001). The Benson symptom score was excellent in 15 cases, good in 12 cases, fair in 2 cases, poor in 1 case; thus, the score was excellent or good in 90% of the cases. Preoperative ultrasound diagnosis and intra-operative findings matched up in all cases. There were four cases of transient numbness in the posterior thigh.

CONCLUSIONS

Arthroscopic sciatic neurolysis is a safe and effective treatment option for DGS patients who fail conservative treatment. Ultrasound diagnosis matched the arthroscopic findings perfectly. Preoperative Doppler ultrasound can assist surgical decision-making, guide intraoperative release.

Nerve entrapment syndromes: detection by ultrasound

Nerve entrapment syndromes are commonly encountered in clinical practice. Accurate diagnosis and management require a knowledge of peripheral neuroanatomy and the recognition of key clinical symptoms and findings. Nerve entrapment syndromes are frequently associated with structural abnormalities of the affected nerve. Therefore, imaging allows the evaluation of the cause, severity, and etiology of the entrapment. High-resolution ultrasonography can depict early and chronic morphological changes within the entire nerve course and is therefore an ideal modality for diagnosing various nerve entrapment syndromes in different regions. This review article presents some of the most common types of nerve entrapment, with special focus on ultrasound imaging and key findings.

Minimally Invasive Image-Guided Transgluteal Approach for Resection of a Sciatic Nerve Tumor: A Technical Note

There are a variety of surgical approaches to lesions around the sciatic notch. Historically, peripheral nerve surgeons prefer an infragluteal approach involving a large incision with reflection of the gluteus maximus to better visualize the operative field. This approach was imperative when lesion localization was imprecise. Comparatively, orthopedic surgeons prefer a muscle-splitting, transgluteal approach to operate on the static structures of the posterior hip. The transgluteal approach is significantly less morbid, allowing for same-day discharge and less extensive rehab given preservation of the gluteal muscle. In this article we describe the use of dynamic ultrasound imaging to localize and aid in the resection of three unique tumors around the sciatic notch using a minimally invasive, tissue-sparing, transgluteal technique. We offer a comprehensive description of the benefits, anatomic considerations, and nuances of using a transgluteal approach for the resection of lesions at the sciatic notch.

Deep Gluteal Pain Syndrome: Endoscopic Technique and Medium-Term Functional Outcomes

BACKGROUND

Sciatic nerve entrapment is an entity that generates disabling pain, mainly when the patient is sitting on the involved side. According to some studies, the presence of fibrovascular bands has been described as the main cause of this pathology, and the sciatic nerve's decompression by endoscopic release has been described as an effective treatment generally associated with a piriformis tenotomy. The aim of this study was to present the medium-term functional results of endoscopic release of the sciatic nerve without resection of the piriformis tendon.

METHODS

This prospective, observational study included 57 patients who underwent an endoscopic operation for sciatic nerve entrapment between January 2014 and January 2019. In all cases, a detailed medical history was obtained and a physical examination and a functional evaluation were performed using the modified Harris hip score (mHHS), the 12-item International Hip Outcome Tool (iHOT-12), and the visual analog scale (VAS) for pain. All patients had pelvic radiographs and magnetic resonance imaging (MRI) scans of the hip on the involved side and underwent a prior evaluation by a spine surgeon.

RESULTS

This study included 20 male and 37 female patients with a mean age of 43.6 years (range, 24 to 88 years) and a mean follow-up of 22.7 months. The median mHHS improved from 59 to 85 points. The median iHOT-12 improved from 60 to 85 points. The median VAS decreased from 7 to 2. Postoperative complications occurred in 12% of patients: 1 patient with extensive symptomatic hematoma, 3 patients with hypoesthesia, and 3 patients with dysesthesia.

CONCLUSIONS

Endoscopic release of the sciatic nerve by resection of fibrovascular bands without piriformis tenotomy is a technique with good to excellent functional results comparable with those of techniques in the literature incorporating piriformis tenotomy.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Three-Headed Piriformis Muscle With Splitting of the Common Fibular Nerve

Although the division of the piriformis muscle by the sciatic nerve or its branches is fairly common, other anatomical variations of this muscle are relatively uncommon. Here, we present a cadaveric case found to have an atypical composition of the piriformis muscle. During the routine dissection of the right gluteal region in an adult male cadaver, an unusual finding of the piriformis muscle was observed. Three distinct heads of the muscle were identified. In addition, one of these heads split the common fibular nerve. The anatomy and relationships of this case are presented here. Any variation in neurovasculature and musculature can be relevant for diagnosing or surgically intervening in the gluteal region. The present case is apparently unique and of archival value.

Physiotherapy for Piriformis Syndrome Using Sciatic Nerve Mobilization and Piriformis Release

Piriformis syndrome is also synonymous with sciatica or buttock pain. This is a condition where the muscle irritates the sciatic nerve. This nerve passes above, below, or in between the piriformis muscle piercing it. The muscle tightens or shortens, thus compressing the nerve and disturbing the impulses passing from it. The sciatic nerve is a combination of nerve roots from L4 to S3. Piriformis works as a lateral rotator and is a synergistic muscle of the flexor and abductor group. Females most commonly present with piriformis syndrome than males. Many causative factors are responsible for the compression or impingement of the sciatic nerve, one of which is piriformis syndrome. Tingling, numbness, and pain are most often felt by patients when they have compression of any of the nerves. Many physiotherapy techniques have been found to be effective in managing this problem. Techniques like nerve mobilization, stretching, myofascial release, deep friction massage, and many more have been studied by authors describing their effects in the treatment of piriformis syndrome. Neural mobilization consists of two techniques, nerve gliding and nerve tensioning. Studies have found that the gliding technique produces less strain on the nerve than the tensioning technique. Piriformis stretch reduces the tightening, which has caused the impingement. Two techniques have been used for this stretch, stretching with hip flexion over 90 degrees and hip flexion under 90 degrees. This review focuses on the different advances in treating piriformis syndrome.

Özkan F. Radiological Comparison of Femoral Neck-Shaft Angle in Piriformis Syndrome: A Case-Control Study

Introduction

Variations in osseous, neural and muscular anatomical structures in the gluteal region have been investigated for their role in causing deep gluteal pain syndromes including piriformis syndrome. This study aimed to radiologically determine whether the femoral neck-shaft angle (NSA) in piriformis syndrome differs from that in a healthy population.

Methods

Two groups of participants comprising 23 piriformis syndrome patients and 22 healthy controls were included in the present study. Piriformis syndrome was diagnosed based on clinical findings and the diagnosis was confirmed by intramuscular local anaesthetic injection. Femoral NSAs were measured from the anteroposterior pelvic radiographs and compared between the control and piriformis syndrome-affected groups.

Results

The age, height, body weight, body mass index and gender distribution differences between the two groups (control and piriformis) were not statistically significant. The femur NSA was significantly lower in the piriformis group than in the control group. The receiver operating characteristic analysis revealed that the area under the curve, sensitivity and specificity for predicting the risk of piriformis syndrome (PS) were 0.946%, 100% and 86.36%, respectively, at an NSA cut-off of 127°.

Conclusions

Reduced femoral NSA is related to PS. However, studies with a larger study sample are needed to further substantiate this finding.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-022-00736-y.

Posttraumatic cicatricial sciatic nerve entrapment: dynamic imaging and percutaneous neurolysis

We describe a case of late-onset sciatic neuralgia due to cicatricial tethering of the sciatic nerve by a retracted torn hamstring muscle that was successfully treated with percutaneous neurolysis. Ultrasound and MRI showed a chronic complete avulsion of the proximal hamstring complex with fatty atrophy of the retracted hamstring muscles. Dynamic ultrasound and magnetic resonance imaging displayed tethering of the retracted hamstring complex to the sciatic nerve caused by cicatricial adhesions. Whereas hamstring injuries are highly prevalent sports injuries, there are only a small number of reported cases in the literature of late-onset sciatic nerve involvement. We highlight the benefits of dynamic ultrasound and magnetic resonance imaging and propose ultrasound-guided percutaneous neurolysis as a viable minimally invasive treatment option.

Piriformis syndrome: muscle thickness or volume does not correlate with response to CT-guided injection

OBJECTIVE

To determine whether size of the piriformis muscle, as characterized by either the coronal width or a segmented volume, correlates with outcomes after CT-guided injections.

MATERIALS AND METHODS

A consecutive series of 81 patients with piriformis syndrome received CT-guided injections of the sciatic nerve and piriformis muscle. Volume and thickness measurements of the piriformis were taken from T1W and T2W pre-injection images by two readers. A logistic regression was used to test volume and size effect on first injection response. A cox proportional hazards model was used to evaluate pain-free survival. Identical analyses were performed to test the effects of muscle mass abnormality, nerve abnormality, body mass index, and presence of a split sciatic nerve.

RESULTS

There were 15/94 negative responses, 31/94 possible positive responses, and 48/94 positive responses to CT-guided injection. The average pain-free survival time was 38.91 ± 64.43 days. There was no significant correlation of first injection responses with muscle thickness or volume. There was no significant correlation in pain-free survival for muscle thickness or volume. There was no significant correlation in first injection response or pain-free survival with body mass index, muscle abnormalities, nerve abnormalities, or split sciatic nerves. The intraclass correlation was excellent between the two readers for both muscle volume (0.95-0.98) and thickness (0.92-0.97).

CONCLUSION

Piriformis muscle volume or thickness did not significantly correlate with post-injection outcome (first injection response and pain-free survival). Thus, if the patient has clinical symptoms of piriformis syndrome, the size of muscle should not determine whether injection is advisable.

Ultrasonographic Evaluation of Peripheral Nerves: Technical Considerations

Advances in ultrasonographic (US) technology featuring high-resolution transducers have revolutionized US over recent years as a modality increasingly used in the evaluation of musculoskeletal structures and peripheral nerves. A wide variety of nerve pathologies can be detected, such as neoplastic and tumorlike lesions, entrapment syndromes, posttraumatic injuries, and inflammatory conditions. US can serve as an imaging tool for guiding percutaneous treatments, such as injection therapies or hydrodissection, and assist with perioperative nerve marking and visualization of peripheral nerves in the operating room. This article describes the normal US appearance of peripheral nerves, US imaging techniques, common peripheral nerve pathologies, and interventional applications.

Endoscopic Sciatic Neurolysis for Deep Gluteal Syndrome: A Systematic Review

Deep gluteal syndrome (DGS) is an underdiagnosed condition caused by an extra-spinal entrapment of the sciatic nerve in the deep gluteal space. Symptomatic patients who fail conservative treatment require surgical decompression of the nerve either by an open or endoscopic approach. In recent times, there has been an increasing trend towards minimally invasive surgery performed with endoscopic techniques. This systematic review aimed to assess the effectiveness of endoscopic sciatic nerve decompression in the management of DGS. A comprehensive search of the PubMed, Web of Science, Cumulated Index to Nursing and Allied Health Literature (CINAHL), and SPORTDiscus databases were performed on January 3, 2022. All English-language clinical studies on DGS treated with endoscopic surgical decompression were included. The initial search criteria identified 145 articles, of which four studies were available for the final review. There was one level III evidence, while the remaining three were level IV, comprising 144 patients with a mean age of 46 years. The Coleman methodology score (CMS) was utilized to assess the quality of the studies and the mean score was 62 (range, 52 to 71). The presence of fibrovascular bands and bursal tissue was the most common cause of DGS, followed by musculotendinous structures. The average follow-up of the included studies was 26.3 months (range, 12 to 32 months). Less favorable outcomes were seen in patients with major traumatic sciatic neuropathies after fractures or open reconstructive hip surgeries. Conversion to formal open surgery was recorded in one case of DGS caused by sciatic nerve schwannoma due to poor endoscopic access. One patient developed postoperative recurrent sciatic nerve entrapment due to a foreign body reaction requiring an open decompression. Overall, the available studies reported a high degree of clinical success with a low rate of complications, albeit no high-quality studies could be identified.

Sciatic nerve movement in the deep gluteal space during hip rotations maneuvers

We hypothesize that the sciatic nerve in the subgluteal space has a specific behavior during internal and external coxofemoral rotation and during isometric contraction of the internal and external rotator muscles of the hip. In 58 healthy volunteers, sciatic nerve behavior was studied by ultrasound during passive internal and external hip rotation movements and during isometric contraction of internal and external rotators. Using MATLAB software, changes in nerve curvature at the beginning and end of each exercise were evaluated for longitudinal catches and axial movement for transverse catches. In the long axis, it was observed that during the passive internal rotation and during the isometric contraction of external rotators, the shape of the curve increased significantly while during the passive external rotation and the isometric contraction of the internal rotators the curvature flattened out. During passive movements in internal rotation, on the short axis, the nerve tended to move laterally and forward, while during external rotation the tendency of the nerve was to move toward a medial and backward position. During the isometric exercises, this displacement was less in the passive movements. Passive movements of hip rotation and isometric contraction of the muscles affect the sciatic nerve in the subgluteal space. Retrotrochanteric pain may be related to both the shear effect of the subgluteus muscles and the endoneural and mechanosensitive aggression to which the sciatic nerve is subjected.

Inferior gluteal pain with sitting, unrelated to ischial bursitis

A 64-year-old woman presented to an academic medical centre with postoperative left ischial pain following a left total hip replacement. Her pain was exacerbated by sitting down and with forward flexion of the spine, and the pain radiated from the left ischial tuberosity to the left perineum, groin and medial thigh. An ischial bursa injection was performed, but only resulted in 1 day of excellent pain relief. A diagnosis of inferior cluneal neuralgia was then made. Subsequent inferior cluneal nerve radiofrequency ablation was performed, and provided sustained 50% relief in pain. The patient had a concomitant sensation of 'ball like' pressure at her rectum which was determined to be due to levator ani syndrome. She was prescribed pelvic floor physical therapy and botulinum toxin injection, which resulted in further notable improvement of her symptoms.

Ultrasound-Guided Measurement of Piriformis Muscle Thickness to Diagnose Piriformis Syndrome

Background: Piriformis syndrome (PS) is a neuromuscular condition caused by the entrapment of the sciatic nerve at the level of the piriformis muscle (PM). Diagnosing PS remains challenging despite recent invasive and non-invasive diagnostic methods. Response to invasive nerve block is still one of the most reliable diagnostic modalities because there is no gold standard test for PS. As early diagnosis may prevent delayed diagnosis that results in chronic somatic dysfunction and muscle weakness, a screening test with high sensitivity could guide clinicians in performing the next appropriate step in diagnosing PS.

Aim: The purpose of this study is to determine the sensitivity, specificity, and best cut-off point of ultrasound-guided PM thickness in PS.

Method: This case-control study was conducted in a general hospital in Tangerang during a 3-month period. We recruited 58 patients clinically diagnosed with PS and 58 healthy patients (without a history of hip and buttock pain) during their visits to the outpatient clinic. All patients underwent ultrasound assessment to measure bilateral PM thickness. Sex, age, body mass index, history of micro-/macro-trauma, and prolonged sitting duration were recorded. Statistical analyses were performed using the Statistical Package for the Social Sciences version 25.

Result: The PS and control groups predominantly comprised female subjects, with mean ages of 51.79 ± 14.10 and 50.09 ± 13.26 years on PS and healthy subjects, respectively. The mean ultrasound-guided PM thickness was higher in PS subjects compared to healthy subjects with mean thicknesses of 1.16 ± 0.13 and 0.85 ± 0.11 cm, respectively (p < 0.05). The area under the receiver operating characteristic curve of the PM was 0.970 (95% confidence interval 0.943–0.998, p < 0.05). The best cut-off point defined by Youden's J index was 0.9950 cm for all PS subjects.

Conclusion: We propose 0.9950 cm as the cut-off point for diagnosing PS by ultrasound, which has the sensitivity and specificity of 94.8 and 87.9%, respectively.

Laparoscopic surgical approach for the treatment of piriformis syndrome: Intrapelvic decompression technique

Introduction:

Piriformis syndrome is an uncommon disease resulting from the piriformis muscle’s compression of the sciatic nerve. Pain and numbness in the buttocks and down the leg are the most common symptoms. This study analyzes the laparoscopic surgical treatment of piriformis syndrome.

Methods:

We report three cases of piriformis syndrome diagnosed in our hospital. The first case was a 40 years old woman with a 7-year history of intermittent low back pain and sciatica on her right side. Hyperesthesia and cutaneous allodynia were observed in the right sciatic nerve dermatome. The second case was a 30 years old woman with a 2-year history of sciatica on her left side. The third case was a 30 years old woman with a 2-year history of sciatica on her right side. All the patients underwent laparoscopic decompression surgery, which was performed to release the sciatic nerve or sacral nerve roots.

Results:

The patients were reexamined at the postoperative 3rd and 6th months. Their visual analog scale (VAS) scores were found to be decreased from 10/10, 9/10, and 7/10 to 0/10, 1/10, and 0/10, respectively.

Conclusion:

Due to the very few cases in the literature, pelvic piriformis syndrome is an exclusively clinical diagnosis. If the sciatica is refractory to conservative treatments, laparoscopic exploration and decompression surgery of the pelvic nerves and piriformis muscle could be an option.

The Importance of Sacral Neuroanatomy in Pain Syndromes and Procedures

: The neural plexus exists in different parts of the body. The sacral plexus is the lowest neural network in the body that is responsible for sensory and motor innervation to a large part of the body. The sacral plexus or sacral nerve roots may be damaged by diseases, such as disc herniation, spinal canal stenosis, and cancer or iatrogenic injuries during surgery or interventional pain procedures (open spinal surgeries, hip surgeries, percutaneous endoscopic disc decompression, trans-sacral epiduroscopic laser decompression, …). Patients with sacral nerve damage may experience a variety of symptoms, including low back pain radiating to the legs, sensory disturbance in the buttocks or legs, motor weakness in the legs, bladder or bowel dysfunction (urinary retention/incontinence, defecation’s problems), or sexual dysfunction. Therefore, complete familiarity with the anatomy of the sacral plexus is very important. In this article, we tried to review the anatomy of the sacral plexus and sensory or motor innervations of each terminal branch of the sacral plexus. Also, the clinical importance of these nerves in the development of pain syndromes and diagnostic and therapeutic methods for damage to the terminal branches of the sacral plexus were investigated.

A Novel Physical Examination Test for Ischiofemoral Impingement: Validation With Magnetic Resonance Imaging Correlation

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.

Deep Gluteal Syndrome: A Pain in the Buttock

ABSTRACT

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.

Pathogenesis and contemporary diagnoses for lateral hip pain: a scoping review

PURPOSE

Recent advances in diagnostic imaging techniques and soft tissue endoscopy now allow for precise diagnosis and management of extra-articular hip pathology. The aim of this scoping review is to present an evidence-based update of the relevant literature focussing only on the pathoanatomy, clinical assessment and the diagnosis of pathology in the peritrochanteric space.

METHODS

A literature search was performed on PubMed to include articles which reported on the anatomy and diagnosis of greater trochanteric pain syndrome, trochanteric bursitis, gluteus medius tears and external snapping hip syndrome.

RESULTS

A total of 542 studies were identified, of which 49 articles were included for full text analysis for the scoping review. Peritrochanteric space pathology can be broadly classified into (1) greater trochanteric pain syndrome (GTPS), (2) abductor tears and (3) external snapping hip syndrome. Anatomically, gluteus medius, gluteus minimus and tensor fascia lata work in conjunction to abduct and internally rotate the hip. The anterolateral part of the gluteus medius tendon is more prone to tears due to a thin tendinous portion. Increased acetabular anteversion has also been shown to be associated with gluteal and trochanteric bursitis. In terms of clinical examination, tests which were found to be most useful for assisting in the diagnoses of lateral hip pain were the single-leg stance, resisted external derotation of the hip, hip lag sign and the Trendelenburg's test. Dynamic ultrasound along with guided injections and MRI scan do assist in differentiating the pathology and confirming the diagnosis in patients presenting with lateral hip pain. Finally, the assessment of baseline psychological impairment is essential in this group of patients to ensure outcomes are optimised.

CONCLUSION

Lateral hip pain used to be a poorly defined entity, but advances in imaging and interest in sports medicine have led to a better understanding of the pathology, presentation and management of this cohort of patients. A thorough appreciation of the anatomy of the abductor musculature, specific clinical signs and imaging findings will lead to an appropriate diagnosis being made and management plan instituted.

LEVEL OF EVIDENCE

IV.

Current advances and novel research on minimal invasive techniques for musculoskeletal disorders

The present review summarized the current advances and novel research on minimal invasive techniques for musculoskeletal disorders. Different invasive approaches were proposed in the physical therapy field for the management of musculoskeletal disorders, such as ultrasound-guided percutaneous needle electrolysis, dry needling, acupuncture and other invasive therapy techniques, discussing about their worldwide status, safety and interventional ultrasound imaging. Indeed, dry needling may be one of the most useful and studies invasive physical therapy applications in musculoskeletal disorders of different body regions, such as back, upper limb, shoulder, arm, hand, pelvis, lower limb, neck, head, or temporomandibular joint, and multiple soreness location disorders, such as fibromyalgia. In addition, the assessment and treatment by acupuncture or electro-acupuncture was considered and detailed for different conditions such as plantar fasciitis, osteoarthritis, spasticity, myofascial pain syndrome, osteoporosis and rheumatoid arthritis. As an increasing technique in physical therapy, the use of ultrasound-guided percutaneous needle electrolysis was discussed in injuries of the musculoskeletal system and entrapment neuropathies. Also, ultrasound-guided percutaneous neuromodulation was established as a rising technique combined with ultrasound evaluation of the peripheral nerve system with different clinical applications which need further studies to detail their effectiveness in different musculoskeletal conditions. Thus, invasive physical therapy may be considered as a promising approach with different novel applications in several musculoskeletal disorders and a rising use in the physiotherapy field.

Imaging of peripheral nerve causes of chronic buttock pain and sciatica

Chronic buttock pain is a common and debilitating symptom, which severely impacts daily activities, sleep, and may affect athletic performance. Lumbar spine, posterior hip, or hamstring pathology are usually considered as the primary diagnoses; however, pelvic neural pathology may be a significant cause of chronic buttock pain, particularly if there are prolonged (>6 months) buttock and/or radicular symptoms. The subgluteal space is the site of most pelvic causes of neural-mediated buttock pain, primarily relating to entrapment neuropathy of the sciatic nerve (deep gluteal syndrome), although other nerves within the subgluteal space including the gluteal nerves, pudendal nerve, and posterior cutaneous nerve of thigh may also be involved. Additionally, cluneal nerve entrapment at the iliac crest may result in "pseudo-sciatica". Anatomical variants of the pelvic girdle muscles and functional factors, including muscle spasm and pelvic instability, may contribute to development of deep gluteal syndrome, along with neural senescence. Imaging findings primarily relate to the presence of sciatic neuritis and peri-sciatic pathology, including neural compression and peri-neural adhesions or fibrosis. This imaging review describes the causes, magnetic resonance imaging and ultrasound imaging findings and imaging-guided treatment of pelvic neural causes of chronic buttock pain and sciatica.

Optimizing the Femoral Offset for Restoring Physiological Hip Muscle Function in Patients With Total Hip Arthroplasty

Objective

Femoral offset (FO) restoration is significantly correlated with functional recovery following total hip arthroplasty (THA). Accurately assessing the effects of FO changes on hip muscles following THA would help improve function and optimize functional outcomes. The present study aimed to (1) identify the impact of FO side difference on the hip muscle moment arms following unilateral THA during gait and (2) propose the optimal FO for a physiological hip muscle function.

Methods

In vivo hip kinematics from eighteen unilateral THA patients during gait were measured with a dual-fluoroscopic imaging system. The moment arms of thirteen hip muscles were calculated using CT-based 3D musculoskeletal models with the hip muscles’ lines of actions. The correlation coefficient (R) between FO and hip muscle moment arm changes compared with the non-implanted hip was calculated. We considered that the FO reconstruction was satisfactory when the abductor moment arms increased, while the extensor, adductor, and flexor moment arms decreased less than 5%.

Results

A decreased FO following THA was significantly correlated with a decrease of the abductor and external rotator moment arms during the whole gait (R > 0.5) and a decrease of extensor moment arms during the stance phase (R > 0.4). An increased FO following THA was significantly associated with shorter flexor moment arms throughout the gait (R < −0.5) and shorter adductor moment arms in the stance phase (R < −0.4). An increase in FO of 2.3–2.9 mm resulted in increased abductor moment arms while maintaining the maximum decrease of the hip muscles at less than 5.0%.

Conclusion

An increase of 2–3 mm in FO could improve the abductor and external rotator function following a THA. Accurate surgical planning with optimal FO reconstruction is essential to restoring normal hip muscle function in THA patients.

Little needle-scalpel for piriformis syndrome: A protocol for systematic review and meta-analysis

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.

The deep gluteal (piriformis) syndrome

Piriformisa syndrome is a subgroup of the deep gluteal syndrome, an important differential diagnosis of sciatica. Piriformis is a short external rotator muscle of the hip joint passing close to the sciatic nerve as it passes through the great sciatic foramen. Compression causes numbness, ache or tingling in the buttocks, posterolateral aspect of the leg and foot. The causes of sciatic nerve entrapment in the deep gluteal syndrome are best shown by endoscopic exploration. The frequency of anatomical variants in normal subjects however, should caution that such anomalies are not necessarily the cause of symptoms.

Piriformis syndrome: pain response outcomes following CT-guided injection and incremental value of botulinum toxin injection

PURPOSE

Piriformis syndrome is a common pain condition affecting the buttock and posterior hip with or without radiation to the leg, and management of the condition involves many treatments. In this study, we hypothesize that a CT-guided injection with botulinum toxin is more effective in providing pain relief than a CT-guided injection without Botox.

METHODS

Overall, 97 consecutive patients with piriformis syndrome presented for a CT-guided injection of the piriformis muscle and perineural injection of the sciatic nerve. After the injection, the patients received a visual analog scale pain log to record their pain level until the follow-up appointment. P values of less than 0.2 were considered as confounder and adjusted by inverse probability of treatment weighting (IPTW) via propensity score. The effect of botulinum toxin on 48-hour response and duration of response was tested using weighted chi-square test and weighted Kaplan-Meier analysis.

RESULTS

There was a total of 97 patients in the study, and 111 injections, as some patients had bilateral injections. Patients in the Botox group had more 48-hour response than patients in the non-botulinum toxin group (P < 0.001 with IPTW, P = 0.005 without IPTW). Median pain-free survival was 30 days for Botox group and 1 day for non-Botox group (P = 0.059 with IPTW, P = 0.10 without IPTW).

CONCLUSION

CT-guided injections with botulinum toxin for patients with piriformis syndrome are more likely to lead to a positive response and a longer duration of response than patients who receive a CT-guided injection without botulinum toxin. We hope that this study facilitates future prospective randomized blind trials for patients with suspected piriformis syndrome.

Magnetic Resonance Neurography for Evaluation of Peripheral Nerves

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.

Proximal hamstring tendinopathy; expert physiotherapists' perspectives on diagnosis, management and prevention

OBJECTIVES

To explore and summarise expert physiotherapists' perceptions on their assessment, management and prevention of proximal hamstring tendinopathy (PHT).

METHODS

We conducted semi-structured interviews with expert physiotherapists until data saturation was met (n = 13). Interviews were transcribed verbatim and data were analysed systematically and organised into categories and sub-categories according to study aims.

RESULTS

Experts report using a clinical reasoning-based approach, incorporating information from the patient interview and results of clinical load-based provocation tests, in the physical examination to diagnose PHT. Experts manage the condition through education and progressive loading targeting the hamstring unit and kinetic chain, avoiding provocative activities in positions of compression in early-mid stage rehab and a gradated and controlled return to sport. Passive therapies including injection therapies and surgery were believed to have limited utility. Prevention of recurrence primarily involved continuation of hamstring and kinetic chain strengthening programs and management of physical workload.

CONCLUSION

Experts rely on a combination of information from the patient interview and a battery of pain provocation tests to diagnose PHT. Education and graded exercise of the hamstring group and synergists, minimising early exposure to hip flexion, were the foundation of management of the condition.

Clinico-radiological review of peripheral entrapment neuropathies - Part 2 Lower limb

PURPOSE

This review discusses the relevant anatomy, etiopathogenesis, current notions in clinical and imaging features as well as management outline of lower limb entrapment neuropathies.

METHODS

The review is based on critical analysis of the current literature as well as our experience in dealing with entrapment neuropathies of the lower limb.

RESULTS

The complex anatomical network of nerves supplying the lower extremities are prone to entrapment by a heterogenous group of etiologies. This leads to diverse clinical manifestations making them difficult to diagnose with traditional methods such as clinical examination and electrodiagnostic studies. Moreover, some of these may mimic other common conditions such as disc pain or fibromyalgia leading to delay in diagnosis and increasing morbidity. Addition of imaging improves the diagnostic accuracy and also help in correct treatment of these entities. Magnetic resonance imaging is very useful for deeply situated nerves in pelvis and thigh while ultrasound is well validated for superficial entrapment neuropathies.

CONCLUSION

The rapidly changing concepts in these conditions accompanied by the advances in imaging has made it essential for a clinical radiologist to be well-informed with the current best practices.

Postoperative Deep Gluteal Syndrome After Hip Arthroscopic Surgery

Background

Deep gluteal syndrome (DGS) is an uncommon source of buttock and groin pain, resulting from entrapment of the sciatic nerve in the deep gluteal space. The incidence and risk factors of postoperative DGS after primary hip arthroscopic surgery are currently unknown.

Purpose

To investigate the incidence and risk factors of postoperative DGS after primary hip arthroscopic surgery.

Study Design

Case-control study; Level of evidence, 3.

Methods

This study reviewed 1167 patients who underwent arthroscopic surgery between 2010 and 2018 by a single surgeon at a single center in Japan. DGS was defined using the seated piriformis stretch test, active hamstring test, and evidence of a hypertrophic sciatic nerve on magnetic resonance imaging. Overall, 11 of 1167 patients were diagnosed with DGS postoperatively. The DGS group (n = 11) was compared with the non-DGS group (n = 1156). Patient age, sex, body mass index (BMI), generalized joint laxity (GJL; Beighton score >6), number of hip arthroscopic procedures, and radiographic parameters including lateral center-edge angle, Sharp angle, vertical center anterior angle, Tönnis angle, alpha angle, ischiofemoral distance, ischiofemoral space, and quadratus femoris space were compared. The prevalence of developmental dysplasia of the hip (DDH) and borderline DDH (BDDH) was also compared. Logistic regression analysis was conducted to identify potential predictors for a postoperative DGS diagnosis.

Results

The incidence of postoperative DGS in our study was 0.9%. Female sex (male:female ratio: 0:11 in DGS group vs 568:588 in non-DGS group; P < .01), mean number of hip surgical procedures (1.8 ± 0.9 in DGS group vs 1.1 ± 0.4 in non-DGS group; P < .01), and GJL (P < .01) were significantly higher in the DGS group, while the mean BMI was significantly lower in the DGS group (19.8 ± 1.8 vs 22.7 ± 3.6 kg/m², respectively; P < .01). Radiographic parameters were not significantly different between groups. Logistic regression analysis revealed that female sex (odds ratio [OR], 22.0 [95% CI, 1.29-374.56]), multiple surgical procedures (OR, 7.8 [95% CI, 2.36-25.95]), GJL (OR, 40.9 [95% CI, 8.74-191.70]), lower BMI (OR, 0.77 [95% CI, 0.644-0.914]), and DDH/BDDH (OR, 18.1 [95% CI, 2.30-142.10]) were potential predictors of postoperative DGS.

Conclusion

The incidence of postoperative DGS in our study was 0.9%. The predictors for postoperative DGS after hip arthroscopic surgery were female sex, GJL, multiple hip surgical procedures, and DDH/BDDH. Although hip arthroscopic surgery can provide favorable clinical outcomes, surgeons should be aware of the risk factors for DGS as a complication of hip arthroscopic surgery.

Imaging of chronic male pelvic pain: what the abdominal imager should know

Chronic pelvic pain is an important but underrecognized cause of morbidity in men. While there is abundant literature discussing female pelvic pain and the diagnostic role of imaging, much less attention has been given to imaging of non-gynecologic causes of chronic pelvic pain. Chronic pelvic pain in men can be a challenge to diagnose as pain may arise from visceral, musculoskeletal, or neurovascular pathology. Imaging of the pelvic viscera has been covered in detail elsewhere in this edition and therefore will not be reviewed here. We will focus upon topics less familiar to the abdominal radiologist, including imaging of pelvic floor, musculoskeletal, and neurovascular pathology.

Deep gluteal syndrome as a cause of posterior hip pain and sciatica-like pain

Deep gluteal syndrome is an increasingly recognized disease entity, caused by compression of the sciatic or pudendal nerve due to non-discogenic pelvic lesions. It includes the piriformis syndrome, the gemelli-obturator internus syndrome, the ischiofemoral impingement syndrome, and the proximal hamstring syndrome. The concept of the deep gluteal syndrome extends our understanding of posterior hip pain due to nerve entrapment beyond the traditional model of the piriformis syndrome. Nevertheless, there has been terminological confusion and the deep gluteal syndrome has often been undiagnosed or mistaken for other conditions. Careful history-taking, a physical examination including provocation tests, an electrodiagnostic study, and imaging are necessary for an accurate diagnosis. After excluding spinal lesions, MRI scans of the pelvis are helpful in diagnosing deep gluteal syndrome and identifying pathological conditions entrapping the nerves. It can be conservatively treated with multidisciplinary treatment including rest, the avoidance of provoking activities, medication, injections, and physiotherapy. Endoscopic or open surgical decompression is recommended in patients with persistent or recurrent symptoms after conservative treatment or in those who may have masses compressing the sciatic nerve. Many physicians remain unfamiliar with this syndrome and there is a lack of relevant literature. This comprehensive review aims to provide the latest information about the epidemiology, aetiology, pathology, clinical features, diagnosis, and treatment. Cite this article: Bone Joint J 2020;102-B(5):556-567.