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.

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.

Epidemiology and etiology of secondary piriformis syndrome: A single-institution retrospective study.

Piriformis syndrome (PS) is a rare etiology of extra-spinal sciatica in which pathologies associated with or around the piriformis muscle (PM) irritate the adjacent sciatic nerve (SN), however, there is scarcity in the literature regarding its exact etiologies, thus, we performed a retrospective study to elucidate the epidemiology of PS and assess various causes of the syndrome. Our study included patients assessed at our institution who presented with sciatica of non-spinal origin between May 2014 and December 2015. Radiology reports of all patients who received pelvic MRI were examined for positive findings involving PM and SN. Of the 143 patients recognized with sciatica and negative lumbar pathology, 24 patients (17%) exhibited positive PM and SN findings. Average patient age was 50.0 ±â€¯15.1 years (range: 21-75), and 17 were female. Seven patients (5%; 4M/3F) presented with tumor, seven patients (5%) had chronic inflammatory changes, one patient had SN adhesions to obturator muscle, three patients (2%, 3F) had aberrant anatomy, and the remaining patients had positive MRI findings, such as nerve atrophy or PM hypertrophy without identifiable cause. Seven patients received steroid injections in the peri-sciatic fossa, and four displayed poor response. Our findings suggested possible trends in extra-spinal sciatica. Affected males appeared more likely to present with tumor, while affected females were more likely to present younger, but with aberrant anatomy. Steroid injections appeared to be suboptimal in most cases. Pelvic MRI is helpful in patients with sciatica and negative spine imaging to rule out neoplastic involvement.

Prevalence of piriformis syndrome in chronic low back pain patients. A clinical diagnosis with modified FAIR test.

PURPOSE: Piriformis syndrome is a collection of symptoms and signs of pain from piriformis muscle and is characterized by pain in buttock with variable involvement of sciatic nerve. This syndrome is often overlooked in clinical practice because its presentation has similarities with other spine pathologies. A major problem with the clinical diagnosis of piriformis syndrome is the lack of consistent objective findings and an absence of single test that is specific for piriformis syndrome. Therefore, a precise and reliable clinical method of diagnosing piriformis syndrome should be developed by clinicians. METHODS: This is a prospective observational study involving 93 consecutive patients who attended the pain management unit for chronic low back pain. The diagnosis of piriformis syndrome was made using the modified flexion adduction internal rotation (FAIR) test, which is a combination of Lasègue sign and FAIR test. Prevalence of piriformis syndrome based on this technique was compared with the previous data using other techniques. Chi square (χ2) analysis was performed to detect the relationship between piriformis syndrome and the potential risk factors. RESULTS: On the basics of our diagnostic criteria, the prevalence of piriformis syndrome was 17.2% among low back pain patients. All the patients diagnosed with piriformis syndrome responded well with piriformis muscle injections. No significant associations were detected between piriformis syndrome and spine disorders. CONCLUSIONS: Piriformis syndrome is a painful condition that is often overlooked in the differential diagnosis of chronic buttock or low back pain. The modified FAIR test together with piriformis muscle injection is potentially a reliable method for the clinical diagnosis of piriformis syndrome.

Piriformis syndrome after percutaneous endoscopic lumbar discectomy via the posterolateral approach.

Percutaneous endoscopic lumbar discectomy (PELD) can be performed under local anesthesia with intravenous analgesics. To define the incidence of piriformis syndrome (PS) after PELD via the posterolateral approach under local anesthesia compared to that of general patients presenting with low back pain with/without lower leg pain. The incidence and time of occurrence of positive FAIR test after PELD within a 3-month follow-up period were evaluated retrospectively, and compared with the prevalence of general patients who visited the pain clinic for LBP with/without lower leg pain. Factors that may increase the incidence of PS after PELD were also evaluated. There was no patient with positive FAIR test immediately after PELD in the operation room and before walking. The prevalence of PS in general patients was 317/2,320 (13.7%); however, the incidence of PS after PELD within a 3-month follow-up period was 61/151 (40.4%), peaking at 32 days. High anxiety scale scores during operation led to increased incidence of PS after PELD. PELD under local anesthesia with high level of anxiety may increase the incidence of PS after walking, peaking around the first month, compared with the results for general patients with low back pain with/without lower leg pain.