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.

An Extremely Rare Case of a Sciatic Nerve Variant.

The sciatic nerve (SN) is the nerve of the posterior compartment of the thigh and typically traverses beneath the piriformis muscle (PM) before continuing along a vertical course deep to the gluteus maximus and biceps femoris. However, cadaveric studies have often revealed significant variations in the structural features of the SN in relation to the piriformis. Knowledge of such variations is not only useful for clinicians treating pathophysiologies such as piriformis syndrome and sciatica but is also essential for surgeons carrying out procedures involving the hip and sacroiliac joints to avoid iatrogenic injury to the SN. During routine cadaveric dissection, one such anatomical variant was identified with the SN passing over the superior border of the piriformis muscle. To our knowledge, such a variant is exceedingly rare.

Left Gluteal Maximus Neuroma Causing Long-Standing Gluteal Pain.

ABSTRACT: Diagnosing buttock pain is a challenge due to complex anatomy and multiple causes. Potential pathologies range from common and benign to rare and life-threatening. Common causes for buttock pain include referred pain from the lumbar spine and sacroiliac joint, hamstring origin tendinopathy, myofascial pain, ischiogluteal bursitis, gluteal pathology, and piriformis syndrome. Rarer causes include malignancy, bone infection, vascular anomalies, and spondyloarthropathies. Other conditions may be present concurrently in the lumbar and gluteal area, which can cloud the clinical picture. Correct diagnosis and early treatment may improve quality of life by providing a targetable reason for their distress, improving pain, and allowing the patient to get back to their activities of daily living. When treating a patient with buttock pain, it is essential to reevaluate the diagnosis when symptoms fail to improve despite appropriate intervention.Here, we discuss a case of a peripheral nerve sheath tumor found in the left gluteus medius muscle of a patient that caused persistent, debilitating buttock pain. After years of treatment for piriformis syndrome and possible spinous causes, the patient was ultimately diagnosed with a peripheral nerve sheath tumor through magnetic resonance imaging with contrast. Peripheral nerve sheath tumors are a diverse group of mostly benign tumors that can occur sporadically or associated with certain disease processes. These tumors usually present with pain, a soft tissue mass, or focal neurological deficits. Upon removal of the tumor, her gluteal pain completely resolved.

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.

Novel anatomical findings with implications on the etiology of the piriformis syndrome.

PURPOSE: The cause of the piriformis-related pelvic and extra-pelvic pain syndromes is still not well understood. Usually, the piriformis syndrome is seen as extra-pelvic sciatica caused by the entrapment of the sciatic nerve by the piriformis in its crossing through the greater sciatic foramen. However, the piriformis muscle may compress additional nerve structures in other regions and cause idiotypic pelvic pain, pelvic visceral pain, pudendal neuralgia, and pelvic organ dysfunction. There is still a lack of detailed description of the muscle origin, topography, and its possible relationships with the anterior branches of the sacral spinal nerves and with the sacral plexus. In this research, we aimed to characterize the topographic relationship of the piriformis with its surrounding anatomical structures, especially the anterior branches of the sacral spinal nerves and the sacral plexus in the pelvic cavity, as well as to estimate the possible role of anatomical piriformis variants in pelvic pain and extra-pelvic sciatica. METHODS: Human cadaveric material was used accordingly to the Swiss Academy of Medical Science Guidelines adapted in 2021 and the Federal Act on Research involving Human Beings (Human Research ACT, HRA, status as 26, May 2021). All body donors gave written consent for using their bodies for teaching and research. 14 males and 26 females were included in this study. The age range varied from 64 to 97 years (mean 84 ± 10.7 years, median 88). RESULTS: three variants of the sacral origin of the piriformis were found when referring to the relationship between the muscle and the anterior sacral foramen. Firstly, the medial muscle origin pattern and its complete covering of the anterior sacral foramen by the piriformis muscle is the most frequent anatomical variation (43% in males, 70% in females), probably with the most relevant clinical impact. This pattern may result in the compression of the anterior branches of the sacral spinal nerves when crossing the muscle. CONCLUSIONS: These new anatomical findings may provide a better understanding of the complex piriformis and pelvic pain syndromes due to compression of the sacral spinal nerves with their somatic or autonomous (parasympathetic) qualities when crossing the piriformis.

A Novel Piriformis Injection Technique Utilizing Combined Fluoroscopy and Ultrasound - A Pilot Study.

BACKGROUND: Piriformis syndrome is a constellation of symptoms associated with low back, gluteal, and sciatic pain. One treatment for piriformis syndrome is the injection of local anesthetic, steroid, or botulinum toxin into the piriformis muscle. Various approaches for needle navigation into the piriformis muscle have been described using fluoroscopy or ultrasound. This study introduces a new method of image guidance combining fluoroscopy and ultrasound. OBJECTIVES: The primary aim of this study was examining whether the imaging modality used for needle guidance was associated with significant differences in pre- and post-piriformis injection pain scores. Secondary objectives were assessing differences in adverse events and procedure time. STUDY DESIGN: This study is a retrospective cohort study. SETTINGS: This study was conducted at Oregon Health and Science University's Comprehensive Pain Center, Portland, OR, USA. METHODS: Institutional chart review was performed from 09/21/2014 to 01/21/2020 to identify patients that underwent piriformis steroid injections which generated a list of 95 patients and totaled 154 procedures. Inclusion criteria were met for 78 patients and 109 procedures. Pain scores were modeled longitudinally using robust variance estimates. The nonparametric Kruskal-Wallis test was used for procedure duration, while adverse events were too rare to evaluate statistically. RESULTS: Piriformis steroid injections using the combined ultrasound and fluoroscopy technique had the lowest mean post-procedure pain score of 1.3 (SD 1.7) and the largest change in pain with a score difference of -3.9 (SD 2.1). Procedure durations were 8 (quartiles 5 to 10), 10 (quartiles 7 to 13), and 11 minutes (quartiles 9 to 13) for fluoroscopy alone, ultrasound alone, and combined techniques, respectively. All 3 modalities had duration ranges of minimum time of 3-5 minutes and a maximum time of 25-28 minutes. Adverse events across all imaging strategies were noted in 5 patients at the time of procedure and in 7 patients during follow-up appointments, the most common symptom being transient leg weakness or numbness. LIMITATIONS: The major limitation is the retrospective collection of data. Another limitation is that 6 different providers performed the injections, which may influence procedural consistency. Additionally, the inclusion of subjects with low pre-procedure pain scores could create a floor effect that minimized the occurrence of clinically significant shifts in pain scores. Adverse events were too few across all groups to assess. CONCLUSION: Piriformis injections using combined fluoroscopic and ultrasound guidance provides comparable efficiency to standard techniques and may result in improved accuracy into the target and thus improved efficacy. Larger prospective trials are required to comprehensively examine the efficacy of this novel technique.

[New treatment options for piriformis syndrome]. / Novye vozmozhnosti terapii sindroma grushevidnoi myshtsy.

This paper discusses modern approaches to the diagnosis and management of patients with piriformis syndrome. Epidemiological data on the prevalence of this syndrome in neurological practice are presented. The anatomical features of this region, leading to the formation of piriformis syndrome, are described in detail. The authors provide diagnostic criteria based on neurological examination and manual muscle testing and discuss the differential diagnosis of piriformis syndrome. New possibilities of treating this syndrome using a fixed combination of diclofenac and orphenadrine registered in the Russian Federation as a drug for intravenous infusion neodolpasse are discussed in detail. The authors cite materials from their own work, a clinical case of managing a patient with piriformis syndrome using neodolpasse is analyzed.

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.

Piriformis syndrome as the only initial manifestation of septic sacroiliac osteomyelitis.

Piriformis syndrome refers to sciatica symptoms that do not originate from spinal root compression, but involve the overlying piriformis muscle. Diagnosis is clinical since there are no definitive tests to confirm the diagnosis. Piriformis syndrome is often misinterpreted as sciatica or other pains. Rarely, it could be one of the manifestations of pelvic osteomyelitis. Pelvic osteomyelitis is rare in adults, but it is associated with high morbidity and mortality. One of the severe complications is bacteraemia, which is life-threatening and may be associated with poor outcome. Acute pelvic osteomyelitis is often not initially diagnosed owing to its non-specific symptoms, including fever and severe but poorly localised pain, which may result in a delay of appropriate treatment. Thus, prompt diagnosis is crucial to the prognosis. Here, we report a patient suffering from acute pelvic osteomyelitis with piriformis syndrome as the only initial manifestation without fever. This unusual manifestation rendered prompt and correct diagnosis difficult.

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.

Deep gluteal syndrome is defined as a non-discogenic sciatic nerve disorder with entrapment in the deep gluteal space: a systematic review.

PURPOSE: Clinicians are not confident in diagnosing deep gluteal syndrome (DGS) because of the ambiguity of the DGS disease definition and DGS diagnostic pathway. The purpose of this systematic review was to identify the DGS disease definition, and also to define a general DGS diagnostic pathway. METHODS: A systematic search was performed using four electronic databases: PubMed, MEDLINE, EMBASE, and Google Scholar. In eligibility criteria, studies in which cases were explicitly diagnosed with DGS were included, whereas review articles and commentary papers were excluded. Data are presented descriptively. RESULTS: The initial literature search yielded 359 articles, of which 14 studies met the eligibility criteria, pooling 853 patients with clinically diagnosed with DGS. In this review, it was discovered that the DGS disease definition was composed of three parts: (1) non-discogenic, (2) sciatic nerve disorder, and (3) nerve entrapment in the deep gluteal space. In the diagnosis of DGS, we found five diagnostic procedures: (1) history taking, (2) physical examination, (3) imaging tests, (4) response-to-injection, and (5) nerve-specific tests (electromyography). History taking (e.g. posterior hip pain, radicular pain, and difficulty sitting for 30 min), physical examination (e.g. tenderness in deep gluteal space, pertinent positive results with seated piriformis test, and positive Pace sign), and imaging tests (e.g. pelvic radiographs, spine and pelvic magnetic resonance imaging (MRI)) were generally performed in cases clinically diagnosed with DGS. CONCLUSION: Existing literature suggests the DGS disease definition as being a non-discogenic sciatic nerve disorder with entrapment in the deep gluteal space. Also, the general diagnostic pathway for DGS was composed of history taking (posterior hip pain, radicular pain, and difficulty sitting for 30 min), physical examination (tenderness in deep gluteal space, positive seated piriformis test, and positive Pace sign), and imaging tests (pelvic radiographs, pelvic MRI, and spine MRI). This review helps clinicians diagnose DGS with more confidence. LEVEL OF EVIDENCE: IV.

Case report and review of the potential role of the Type A piriformis muscle in dynamic sciatic nerve entrapment variant of piriformis syndrome.

Piriformis syndrome (PS) is an underdiagnosed but common cause of chronic buttock pain and sciatica. Anatomical variants of the piriformis muscle and sciatic nerve have not been thought to be significant in the pathophysiology of PS however, recent description of the piriformis musculotendinous junction has identified a common variant that we believe frequently results in dynamic sciatic nerve entrapment at the infra-piriformis fossa. We performed ultrasound guided low-dose Botulinum Toxin-A (BTX-A) injection to the lower piriformis muscle belly in an elite Australian Rules football player with PS and Type A piriformis muscle to relieve symptomatic sciatic nerve compression. Positive response to targeted BTX-A piriformis muscle injections support the hypothesis that sciatic nerve compression by Type A piriformis muscles may contribute to the pathophysiology of neuropathic PS, along with other functional factors. Sciatic nerve compression due to Type A piriformis at the infra-piriformis fossa has not been described previously and is a potentially common cause of neuropathic PS, especially when combined with other functional factors such as piriformis muscle spasm/hypertrophy and sacroiliac joint counternutation.

Rash, Radiculopathy, and Cognitive Biases.

BACKGROUND: Physicians rely on intuition and pattern recognition to rapidly evaluate and treat patients. While the realities of our medical system require liberal use of these heuristics to efficiently make clinical decisions, such thinking patterns are error-prone-leaving the clinician at the whims of their cognitive biases.CASE REPORT: We describe a case of Lyme disease in which a pilot's rash and radicular pain were misdiagnosed on two separate occasions until, nearly a month after initially seeking medical care, the pilot was appropriately diagnosed and treated.DISCUSSION: This case highlights Lyme disease's mimicry of other common diseases and underscores the need to use slower, more deliberate evaluation in conjunction with pattern recognition and intuition to provide optimal care to flyers.Saul S, Tanael M. Rash, radiculopathy, and cognitive biases. Aerosp Med Hum Perform. 2019; 90(7):652-654.

Piriformis pyomyositis, a cause of piriformis syndrome-a systematic search and review.

Piriformis pyomyositis is a rare form of purulent skeletal myositis. As previous studies concerning piriformis pyomyositis had lower level of evidence and no systematic review has been published yet, we performed a systematic search to review and describe causes, symptoms, red flags, and available treatment options for piriformis pyomyositis. Using PubMed and PubMed Central databases, we found 21 articles describing 23 cases of piriformis pyomyositis. Based on the retrieved information, alongside acute sciatica like buttock and/or hip pain, high-grade fever, aggressive deep seated gluteal pain, neurological deficit of sciatic nerve distribution, positive straight leg raising test, and raised inflammatory biomarkers (erythrocyte sedimentation rate, ESR, C-reactive protein, CRP) provide clues for diagnosis of piriformis pyomyositis. Some cases were very ill but no death was documented. Staphylococcus aureus was the most common pathogen, but Group A as well as Group ß Streptococcus, Salmonella typhi, Proteus mirabilis, Brucella melitensis, and Escherichia coli were also involved in the disorder. To treat the piriformis pyomyositis, broad-spectrum antibiotics were found to be useful; however, sometimes, antibiotic switching was warranted based on blood and tissue aspirate reports. Drainage and/or surgical exploration of the affected piriformis muscle were required in cases where antibiotics appeared ineffective. Piriformis pyomyositis is a rara avis and performing of prospective studies will hardly be feasible.

Piriformis Syndrome: A Narrative Review of the Anatomy, Diagnosis, and Treatment.

Piriformis syndrome is a form of sciatica caused by compression of the sciatic nerve by the piriformis muscle. It is a relatively uncommon, but not insignificant, cause of sciatica. The diagnosis of piriformis syndrome is complicated by the large differential diagnosis of low back and buttock pain with many diagnoses having overlapping symptoms. This narrative review highlights the relevant anatomy, history, physical exam maneuvers, electrodiagnostic findings, and imaging findings that are used to diagnose piriformis syndrome. Also discussed are posterior gluteal myofascial pain syndromes that mimic piriformis syndrome. The review then outlines the different treatment options for piriformis syndrome including conservative treatment, injections, and surgical treatment. In addition, it provides the reader with a clinical framework to better understand and treat the complex, and often misunderstood, diagnosis of piriformis syndrome.

Ultrasound appears to be a reliable technique for the diagnosis of piriformis syndrome.

INTRODUCTION: Piriformis muscle syndrome (PS) is a disorder encompassing a constellation of symptoms, including buttock and hip pain. In this study we aimed to assess the value of ultrasound (US) in the diagnosis of PS. METHODS: Thirty-three clinically diagnosed PS patients and 26 healthy volunteers underwent a clinical PS scoring examination and US and MRI assessment of the bilateral piriformis muscles. The areas under the receiver operating characteristic curves (AUROCs) of the US parameters (i.e., increased thickness [iTh] and increased cross-sectional area [iCSA]) for piriformis muscle were evaluated. RESULTS: On US and MRI, the thickness and CSA were increased in PS patients. The AUROCs for the iTh and iCSA for discriminating stage 0 (healthy volunteers) from stage 1 through stage 3 (PS patients) were 0.88 and 0.95, respectively. DISCUSSION: US may be a reliable technique for the clinical diagnosis of PS. Muscle Nerve 59:411-416, 2019.

EMG in piriformis syndrome diagnosis: Reliability of peroneal H-reflex according to results obtained after surgery, Botox injection and medical treatment.

Diagnosing piriformis syndrome (PS) throughout the past decades was not that easy, however peroneal H-reflex was proved as reliable test for PS with the change in wave amplitude and delay in conduction as parameters for diagnosis. We interpreted these parameters according to treatment's results carried out for patients presenting clinical PS, aiming to define a threshold value for peroneal H-reflex delay to accurately diagnose. A retrospective mono-centric review of 27 patients, 9 females and 18 males, aged 22-65 years, benefited from peroneal H-reflex test and treated for clinical PS. These patients were classified into 3 groups according to treatment modality they received: 11 patients underwent surgical treatment, 7 patients underwent Botox injections (4 of them benefited from surgery later on) and 9 patients received pharmacological treatment. From 11 operated patients with 4 < delay < 9 ms, 10 had complete improvement and 1 remained in pain. For 7 patients having injection of Botox 100-300 IU, with 5 < delay < 7 ms had a transient recovery, 4 of them have benefited later from surgery, the 3 others reproved pain. Between 9 patients who have declined invasive treatment, 7 patients with 4 < delay < 10 ms didn't demonstrate any improvement after medical treatment and are suspected of PS, 2 others with delay < 4 ms recovered from a non-confirmed PS. A threshold value to diagnose PS was reached through peroneal H-reflex delay ranges, classified as: high with a delay > 5 ms, moderate: 4 < delay < 5 ms and poor: <4 ms.

Letter to the editor involving the article 'Piriformis muscle syndrome: A cross-sectional imaging study in 116 patients and evaluation of therapeutic outcome'.

KEY POINTS: • Lack of use of local injection test to confirm the diagnosis may lead to miss the diagnosis of PMS of myofascial origin. • Piriformis muscle syndrome should be diagnosed on the basis of clinical symptoms, specific physical examinations, and positive response to local injection. • Sciatic nerve entrapment is not a must in the diagnosis of PMS and PMS is mostly myofascial in origin.