Comparing radial extracorporeal shockwave therapy and corticosteroid injection in the treatment of piriformis syndrome: A randomized clinical trial.

OBJECTIVE: This study was designed to compare the effects of shockwave therapy and corticosteroid injection in the treatment of piriformis syndrome. METHODS AND MATERIALS: In this randomized clinical trial, thirty-five patients with piriformis syndrome were randomly divided into two groups of 18 in the shockwave group and 17 in the corticosteroid group. The Shockwave group underwent three sessions of shockwave therapy per week (2000 pulses per session with 5Hz frequency and pressure equal to 4 Bar) and the corticosteroid group underwent an injection of 40 mg methylprednisolone with 1 mL of 1% lidocaine under ultrasound guidance. All patients were assessed by SF-36 questionnaire and visual analogue scale (VAS). The SF-36 questionnaire was used to evaluate the quality of life before and 4 weeks after the intervention. VAS scale was used to evaluate pain before the intervention, and 1, 4, 8, and 12 weeks after the intervention. RESULTS: The baseline characteristics of the two groups were not significantly different. At the end of the study, both groups had a significant improvement in pain and quality of life compared to before the intervention. However, according to the VAS, in the shockwave group improvement was seen in the first follow-up while not seen in the corticosteroid group (P-value <0.001 and P-value 1.00, respectively). According to the SF-36 questionnaire, the overall score in both groups had a significant improvement (P-value <0.05). CONCLUSIONS: It seems that shockwave therapy and corticosteroid injection are both effective in the treatment of piriformis syndrome. There was no significant difference between the two groups in the quarterly follow-up. Because shockwave therapy is a relatively non-invasive treatment with fewer side effects, it can be useful to improve pain and the quality of life of patients with piriformis syndrome.

Botulinum toxin injection strategy of intractable and relapsed piriformis syndrome: A case report.

RATIONALE: Piriformis syndrome (PS) is neuromuscular disorder caused by sciatic nerve compression by piriformis muscle and related to sciatic-type pain. When the conservative care fails, local injection or surgery can be also performed into piriformis. In recent years, botulinum toxin (BoNT) has also been considered as a new therapeutic option of piriformis syndrome. PATIENT CONCERNS: A man in his late 40s came to pain clinic for left low back pain. The symptom was aggravated with sitting position. DIAGNOSIS: Piriformis syndrome. INTERVENTIONS: The patient underwent BoNT injection with 100 IU with 2 mL into piriformis muscle for piriformis syndrome treatment, and his pain was relieved. However, it recurred 8 months later. BoNT injection was repeated with 100 IU with 5 mL. OUTCOMES: At the time of this writing, his pain was reduced for 2 years without any medication. LESSONS: We report a case of treating relapsed piriformis syndrome with BoNT injection of different dilution volume, suggesting that the higher the dilution volume, the more effective for therapeutic effect of BoNT.

Efficacy of Botulinum Toxin, Local Anesthetics, and Corticosteroids in Patients With Piriformis Syndrome: A Systematic Review and Meta-analysis.

BACKGROUND: Piriformis syndrome (PS) is a painful condition caused by entrapment of the sciatic nerve within the piriformis muscle. PS is typically unilateral and mainly occurs related to entrapment of the sciatic nerve. Treatments include physiotherapy, analgesics, anti-inflammatory drugs, behavioral modifications, injection therapy with local anesthetics (LAs) and steroids, epidural injection, botulinum toxin (BT) injection, and surgery. OBJECTIVES: To investigate the efficacy of BT, LA, and corticosteroid (CS) injections in relieving pain in patients affected by PS. STUDY DESIGN: This systematic review and meta-analysis was conducted according to the "Cochrane Handbook for Systematic Reviews of Interventions" and the "Preferred Reporting Items for Systematic Reviews and Metaanalyses (PRISMA)" guidelines. METHODS: A systematic search was conducted through PubMed, Cochrane, Web of Science, and Scopus through April 2021 for studies investigating the efficacy of BT, LA, or CS injection in improving pain in patients with PS. After screening retrieved studies, data were extracted from included studies and pooled. Overall results were reported as standardized mean difference (SMD) and 95% confidence interval (CI). Analysis was performed using RevMan software version 5.4. RESULTS: Sixteen studies were included in this systematic review, and 12 of them were included in the quantitative synthesis. The pain scores decreased significantly after treatment with BT (SMD = -2.00; 95% CI [-2.84, -1.16], P < 0.001), LA and CS (SMD = -4.34; 95% CI [-5.77, 2.90], P < 0.001), LA (SMD = -3.73; 95% CI [-6.47, -0.99], P = 0.008), CS (SMD = -2.78; 95% CI [-3.56, -2.00], P < 0.001), and placebo injection (SMD = -0.04; 95% CI [-0.07, -0.01], P = 0.002). BT injection was less effective than LA and CS together (P = 0.006), more effective than placebo (P = 0.001), and similar to LA (P = 0.24) and CS (P = 0.18), when injected alone. LIMITATIONS: A wide variety of study designs were utilized to obtain the largest sample size available. Many of the included studies lack randomization, and some are retrospective in nature. These limitations may introduce bias into the analyzed data and affect the results. Many studies had a low sample size and are of moderate quality, limiting the generalizability of the results. Also, we could not conduct a direct meta-analysis due to the lack of sufficient double-arm studies comparing different types of injection therapies. CONCLUSIONS: In patients with PS, satisfactory pain improvement can be obtained by BT, LA plus CS, LA, or CS injection therapy. Injection of LA plus CS showed the best efficacy.

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.

Effectiveness of Hydro-Dissection of the Piriformis Muscle Plus Low-Dose Local Anesthetic Injection for Piriformis Syndrome: A Report of 2 Cases.

BACKGROUND Piriformis syndrome causes severe buttock and low back pain and numbness of the lower limbs, leading to difficulty in walking. The lack of unified diagnostic criteria for piriformis syndrome until 2018 made it difficult to diagnose; therefore, it is often underestimated, and some patients do not receive appropriate treatment. Treatment methods include local anesthetic injection, steroid injection, and local botulinum toxin injection. However, the most effective drug for the treatment of severe piriformis syndrome has not been established. This report aimed to propose a new and more effective treatment for piriformis syndrome with a minimal risk of adverse effects. CASE REPORT We performed ultrasound-guided hydro-dissection of the superficial and deep surfaces of the piriformis muscle under local anesthesia (a mixture of 18 mL of saline and 2 mL of 1% lidocaine) in 2 flexion, adduction, and internal rotation test-positive patients with tenderness of the piriformis muscle. In both patients, symptoms improved quickly after injection. One required hospital treatment but gradually returned to previous activities of daily living (ADL) status 5 days after admission and was then discharged. The other patient received 2 injections weekly to improve ADL status with continued lifestyle guidance. CONCLUSIONS Hydro-dissection by ultrasound-guided injection of a very low concentration of local anesthetic is effective and has lower risk of adverse effects, thus making it more convenient for the treatment of piriformis syndrome than conventional treatments, such as local anesthetics, steroids, and botulinum toxin injection.

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.

[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.

Guidelines for botulinum neurotoxin injections in piriformis syndrome.

BACKGROUND: The piriformis muscle is normally involved in piriformis syndrome and can be treated with botulinum neurotoxin using several different injection methods. However, definitive injection guidelines for the muscle have not been reported previously. AIMS: This study aimed to determine the ideal area for injections based on the intramuscular nerve distribution as obtained using a modified Sihler's staining technique. MATERIALS AND METHODS: A modified Sihler's method was applied to the piriformis muscle in 15 specimens. The intramuscular arborization areas were identified based on two anatomical landmarks: (a) the lateral border of the sacrum bone and (b) the greater trochanter. RESULTS: The nerve entry point for both piriformis muscles was found in the area between the lateral border of the sacrum and one-fifth of the distance toward the greater trochanter. The intramuscular nerve distribution for the piriformis muscle had the largest arborization patterns between one-fifth and two-fifths of the distance from the sacrum to the greater trochanter. The piriformis muscle was tendinous from two-fifths of the distance to the greater trochanter. DISCUSSION: This study has yielded suggested optimal injection locations for the piriformis muscle relative to external anatomical landmarks. CONCLUSION: Clinicians can use these guidelines to ensure the effectiveness of not only botulinum neurotoxin injections but also other agents such as steroids, anesthetics, and normal saline. These guidelines will also help to avoid adverse outcomes of injection treatments.

[Piriformis syndrome. Treatment under control of CT fluoroscopy]. / Sindrom grushevidnoi myshtsy. Lechenie pod kontrolem KT-skopii.

OBJECTIVE: To demonstrate one of the effective methods of treatment of the piriformis syndrome under the control of a highly technological visualization method. MATERIAL AND METHODS: Eight patients (7 women and 1 man), aged 44 to 63 years, with piriformis syndrome, were studied from 2016 to 2018. The main complaints of the patients were pain in the lumbosacral spine with irradiation to the gluteal region and/or legs. All patients underwent MRI and/or MSCT of the lumbosacral spine, the pelvic ultrasound, according to the results of which 1 patient was diagnosed with uterine myoma, 5 with lesions of intervertebral discs in the L4-L5 and L5-S1 segments of varying severity in combination with changes in posture. For therapeutic purposes, all patients under the control of CT fluoroscopy were administered to xeomin (n=3), dexamethasone (n=1) or betamethasone (n=4). RESULTS: In all patients, a positive therapeutic effect was observed after 4-12 months for xeomin injections, 2-3 weeks for dexamethasone and up to 3 months for betamethasone. No complications during the manipulations were observed. The authors present a clinical case to describe the botulinum therapy technique under the control of CT fluoroscopy, which allows effective treatment of the piriformis syndrome. CONCLUSION: In the treatment of the piriformis syndrome it is necessary to apply an integrated approach, the leading of which are methods of local impaction on the suffering muscle. Only a methodologically correct injection can increase the effectiveness of treatment in these patients and reduce the risk of complications.

[The piriformis syndrome-a special indication for botulinum toxin]. / Das Piriformissyndrom ­ eine spezielle Indikation für Botulinumtoxin.

The piriformis syndrome (PiS) is a possible cause of gluteal pain radiating into the legs. From a pathophysiological anatomical point of view a division into primary and secondary PiS is made. A primary PiS is based on variants of the course of the sciatic nerve with respect to the piriformis muscle. A secondary PiS occurs as a result of hypertrophy, tension and hardening of the piriformis muscle. Muscular hypertrophy causes an impingement syndrome with pressure on the sciatic nerve in the infrapiriform foramen more often than course variants. A tentative diagnosis of PiS can be made based on anamnestic information, clinical signs of strain and the flexion adduction internal rotation (FAIR) test. If asymmetry or hypertrophy exists, the tentative diagnosis is substantiated with the representation of the piriformis muscle in computed tomography (CT). Thus, a CT-supported botulinum injection (BTX) into the piriformis muscle is indicated. This is a pathogenetic treatment approach leading to a reduction in volume. In most cases a single treatment is sufficient. Since there are no adverse consequences, the BTX into the piriformis muscle is also justified from a diagnostic and therapeutic point of view in cases of primary PiS if the clinical indications are clear and other causes can be ruled out. In an in-house case series the tentative diagnosis of PiS could be made for 19 patients and the effectiveness of BTX was confirmed.

Computed Tomography-Guided Percutaneous Infiltrations for Piriformis Syndrome: A Single-Center Retrospective Study.

Piriformis syndrome (PS), first described by Yeoman in 1928, is a general term referring to low back pain, sciatica, and instability. PS has a 6% incidence rate worldwide. In this study, we aim to retrospectively evaluate the effectiveness of computed tomography (CT)-guided percutaneous infiltration in a series of consecutive PS patients who have symptoms that are refractory to conservative therapies. An institutional database search identified 20 such consecutive patients who underwent infiltration with a mixture of long-acting corticosteroid and local anesthetic. Preoperational evaluation included physical examination and magnetic resonance imaging. The correct position of the 22-gauge spinal needle was verified with CT scan after contrast medium injection. Pain measured before the procedure and at 1 wk and 1, 6, and 12 mo after the procedure was compared by means of a numeric visual scale (NVS) questionnaire. The mean pain score before CT-guided percutaneous infiltration was 8.95 ± 1.432 NVS units. This score was reduced to a mean value of 0.85 ± 0.933 units at 1 wk, 0.90 ± 0.852 at 1 mo, 1.10 ± 1.165 at 6 mo, and 1.20 ± 1.399 at 12 mo follow-up (p < 0.001). Two patients of 20 (10%) underwent a second infiltration that was performed at 7 and 10 d after the first, respectively. No complications were observed. CT-guided infiltration seems to be a feasible, efficacious, and safe approach for pain reduction and mobility improvement in patients with symptomatic PS.

Effect of piriformis injection on neuropathic pain.

OBJECTIVES: The aim of this study was to investigate the effect of a piriformis injection on neuropathic pain in patients with piriformis syndrome. METHODS: Thirty patients with unilateral hip and/or leg pain, a positive FAIR test (increased H-reflex latency with Flexion, Adduction and Internal Rotation), and a trigger point at the piriformis muscle were enrolled in this prospective study. All of the patients exhibited neuropathic pain scored according to the Douleur Neuropathique 4 (DN4) of ≥4 for at least 6 months. All of the patients received 4 mL of lidocaine 2%+1 mL of betamethazone to the piriformis muscle under the guidance of ultrasound. The Numeric Rating Scale (NRS), DN4, and the painDETECT (PD) questionnaire were used for outcome assessment. RESULTS: A statistically significant improvement was seen in all scores (p<0.001) when both first week and first month results were compared with the baseline values. Comparison of the first week results with those of the first month revealed a statistically significant improvement in only the NRS and PD scores (p<0.001). The greatest improvement in all scores was seen in the first week after the injection. A mild increase was seen in all scores at the first month compared to the first week. CONCLUSION: A piriformis injection was found to be effective for both somatic and neuropathic pain in piriformis syndrome patients. Long-term follow-up is needed in order to consider this option alongside other treatment alternatives, like botulinum toxin and myofascial release.

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.

Effect of Mannitol plus Vitamins B in the management of patients with piriformis syndrome.

BACKGROUND: Piriformis syndrome (PS) is an entrapment of the sciatic nerve by the piriformis muscle, or myofascial pain from the piriformis muscle. OBJECTIVE: The aim of this study was to investigate the effectiveness of Mannitol plus Vitamins B regime in the management of PS. METHODS: Twenty two patients were included in this study and received 250 ml of mannitol 20% intravenous infusion for 5 days + Vitamins B (vitamin B1 10 mg + vitamin B2 10 mg + vitamin B12 50 µg PO) for 6 weeks. Clinical outcomes were assessed systematically by clinical tests (tenderness, FAIR test, Beatty's, Freiberg's and Pace's maneuver), Numeric Rating Scale (NRS), Likert Analogue Scale (LAS), and MR examination. RESULTS: The clinical evaluations showed a significant reduction (p< 0.05) of tenderness, FAIR test, Beatty's maneuver, Freiberg's maneuver and Pace's maneuver when compared with baseline evaluation during the 3rd and 6th month follow-ups. A statistically significant improvement of pain was measured by NRS at resting (p< 0.001), at night (p< 0.001) and during activities (p< 0.001) and LAS with prolonged sitting (p< 0.001), standing (p< 0.001) and lying (p< 0.001). Concomitantly, swelling of SN revealed a significant reduction (p= 0.003) from 86.4% to 18.2%. CONCLUSIONS: Mannitol plus Vitamins B is effective in the management of piriformis syndrome and it could be an alternative regime in treating PS.

Electrophysiologically identified piriformis syndrome is successfully treated with incobotulinum toxin a and physical therapy.

INTRODUCTION: Piriformis syndrome is entrapment of the sciatic nerve by the piriformis muscle. METHODS: In this article we describe a 56-person randomized, double-blind, controlled study involving physical therapy and incobotulinum toxin A or placebo. Inclusion criteria were 3-SD delay of posterior tibial (PT) or fibular (FN) H-reflexes on flexion, adduction, and internal rotation (FAIR) testing, and normal paraspinal electromyographic findings. Outcome measures included adverse side effects, visual analog scale (VAS) findings, and H-reflex delay on the FAIR test. RESULTS: Mean intervention VAS score decreased significantly more compared with placebo at 2, 4, 6, 8, 10, and 12 weeks post-injection (P < 0.0001). FAIR test scores for PT, but not FN, decreased significantly more compared with placebo at 2, 4, 6, and 8 weeks post-injection (PT: P = 0.038, 0.003, 0.003, and 0.046). Adverse effects were minimal. VAS slope and PT FAIR test results varied significantly (P < 0.0001). CONCLUSION: Incobotulinum toxin A chemodenervation may be useful for treating piriformis syndrome as identified by the FAIR test. Muscle Nerve 56: 258-263, 2017.

Ultrasound-Guided Hip Procedures.

This article describes the techniques for performing ultrasound-guided procedures in the hip region, including intra-articular hip injection, iliopsoas bursa injection, greater trochanter bursa injection, ischial bursa injection, and piriformis muscle injection. The common indications, pitfalls, accuracy, and efficacy of these procedures are also addressed.

Perisciatic Ultrasound-Guided Infiltration for Treatment of Deep Gluteal Syndrome: Description of Technique and Preliminary Results.

The objective of this study was to describe a perisciatic ultrasound-guided infiltration technique for treatment of deep gluteal syndrome and to report its preliminary clinical results. A mixture of saline (20 mL), a local anesthetic (4 mL), and a corticosteroid solution (1 mL) was infiltrated in the perisciatic region between the gluteus maximus and pelvitrochanteric muscles. Relative pain relief was achieved in 73.7% of the patients, with average preprocedural and postprocedural visual analog scale scores of 8.3 and 2.8, respectively. Fifty percent of patients reported recurrence of discomfort, and the average duration of the therapeutic effect in these patients was 5.3 weeks.