Piriformis syndrome: a systematic review of case reports.

Background: To study the medical history, diagnosis, management, and treatment results of piriformis syndrome (PS).

Methods: Articles published between 1980 and 2024 reporting cases of PS or piriformis muscle sciatica (PMs) case/case series were included. We excluded articles that did not report anagraphic data for singular cases, diagnostic procedure, therapy, and outcome for each case. We searched PubMed database and we retrieved articles from references. We used the Preferred Reporting Items of Systematic Reviews (PRISMA) guidelines to conduct a systematic review of the literature to identify all published cases of PS or piriformis muscle sciatica (PM). Data for all cases were collected in a database and analysed using statistical software (Statistical Package for the Social Sciences for Windows).

Results: Of the 235 articles screened, 97 were included. Data from 212 patients (117 females and 95 males, mean age 43.6 ± 14.8) were collected. 38.2% of the patients in this study had a history of blunt / indirect pelvic trauma or piriform muscle (PM) stress due to vigorous physical activity/sport. 9.0% (19/212) of the patients had previously failed lumbar spine surgery. Before treatment, the diagnosis of PS/PMs was corroborated in 29.7% of patients by intrapelvic magnetic resonance imaging (MRI); 50.5% of the patients had a PS clinical diagnosis. Conservative treatments were effective in treating PS/PMs in 41.1% of patients; 58.9% of patients required surgical treatments. In the group of patients with PS diagnosis made without instrumental finding, the OR of surgical treatment failure occurrence was 5.3. After treatment, the most frequent causes of PS/PMs identified by intraoperative or instrumental findings were the anatomical variant of PM or SN (12.7%) followed by pyomyositis (9.4%) and PM hypertrophy (7.5%). 47.6% of the patients had no instrumental or intraoperative findings.

Conclusions: Intrapelvic MRI was the instrumental examination most frequently used to confirm the diagnosis of PS/PMs prior to treatment. The PS causes most frequently identified were the anatomical variant of PM or SN. In the group of patients with PS diagnosis made without instrumental finding, the OR of surgical treatment failure occurrence was 5.3. To reduce the number of cases of persistent pain after treatment for suspected PS, it is advisable to support the clinical diagnosis through all available instrumental diagnostic procedures. However, considering all the risks that SN surgery can cause, all nonsurgical treatments should be encouraged prior to surgery.  TRIAL REGISTRATION: PROSPERO Reg. No. CRD42025641061.