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

Use of Diagnostic Musculoskeletal Ultrasound in the Evaluation of Piriformis Syndrome: A Review for Rehabilitation Providers

Piriformis Syndrome (PS) is a neuromuscular condition caused by the entrapment of the sciatic nerve at the level of the piriformis muscle (PM) and can cause significant discomfort and disability. PS is often misdiagnosed due to its overlapping symptoms with other lumbar and sciatic issues and as such, diagnosing PS remains challenging despite recent invasive and non-invasive diagnostic methods. Diagnostic musculoskeletal ultrasound (MSK US) offers a non-invasive, cost-effective alternative for the identification and evaluation of PS, providing dynamic, real-time imaging of the PM and adjacent structures. This article reviews the applications, advantages, and procedural insights of MSK US in the diagnosis of PS, emphasizing its relevance in rehabilitation settings. We discuss the technical aspects of ultrasound use, interpretation of findings, and integration into clinical practice, aiming to enhance the diagnostic accuracy and therapeutic outcomes for patients with suspected PS.

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.

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.

A systematic review of conservative and surgical treatments for deep gluteal syndrome

BACKGROUND AND OBJECTIVE

Conservative and surgical treatments, are recommended as the primary treatment in the management of patients diagnosed with deep gluteal syndrome; but evidence supporting superiority of one treatment over another is lacking. The aim of this review is to systematically review the effectiveness of treatments.

DATABASES AND DATA TREATMENT

MEDLINE, EMBASE, Web of Science, Scopus, AMED, Cochrane Library (Central Register of Controlled Trials), and PEDro were screened (to 24 July 2019). Risk of bias of trials and surgical case series were assessed using the Cochrane risk of bias tool and Joanna Briggs Institute Critical appraisal checklists, respectively. Outcomes were reductions in pain or disability. For each outcome, the minimum clinically important difference (MCID) was calculated. A narrative synthesis was performed.

RESULTS

Out of 909 records, thirteen studies with 508 patients were included, eight RCTs with 336 patients and 5 case series with 172 patients. Conservative modalities were: infiltration into muscle of steroid, botulinum toxin, thiochilcoside and colchicine. There was one RCT and five case series of surgery. Only three trials reached an MCID in pain reduction for the intervention. The five surgical studies reached a before and after MCID. Only one study showed an MCID reduction in disability. The overall quality of evidence was low.

CONCLUSION

Given the low quality of evidence, no single conservative treatment can be recommended over another. Clinicians should follow general guidelines on the management of back pain and sciatica for first line treatment, namely physiotherapy. Surgery may have a place for chronic cases.

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.

Use of botulinum neurotoxin in the treatment of piriformis syndrome: A systematic review

OBJECTIVE

To determine the pain, functional and adverse outcomes of patients with piriformis syndrome who received botulinum neurotoxin injection, and to determine the optimal dosing of botulinum neurotoxin and choices of modality used during this intervention.

LITERATURE SURVEY

Systematic review of relevant clinical studies published in English language using PubMed/Medline, Embase and CINAHL databases from October 1, 2002 to October 6, 2020.

METHODOLOGY

A comprehensive search was performed to identify all studies addressing the treatment of piriformis syndrome with botulinum toxin. Two reviewers independently screened the titles, abstracts, and full texts and extracted data based on a set of predefined inclusion and exclusion criteria. 23 full-text articles were identified of which consensus was achieved for seven articles for data extraction and quality assessment. The qualities and risk of potential bias of the seven studies were appraised using the National Heart, Lung and Blood Institute (NIH) Study Quality Assessment tools for case controls, cohort studies and randomized trials.

SYNTHESIS

Seven studies (n = 152 patients) were included consisting of three randomized controlled studies (RCTs), two case control studies and two cohort studies. The qualities of these studies were: Two good and one fair for the RCTs, fair for both the case controls and one good and fair for the cohort studies. Most studies reported some reduction in pain using various modalities to guide injection (CT, EMG, US or fluoroscopy). However, the included studies were heterogeneous, making it difficult to quantify pain reduction. There was minimal description of other functional outcomes. Botulinum toxin A doses range from 100 to 300U. Mild adverse effects were reported with no medical intervention needed.

CONCLUSIONS

There is fair quality of evidence to suggest botulinum toxin is safe to reduce pain in piriformis syndrome. There is insufficient data to quantify pain reduction and to describe other functional outcomes. The optimal dose of botulinum toxin A remains unclear. Modalities to guide botulinum injection into the piriformis muscle remain heterogeneous.

Trigger Point Injections

Myofascial pain and myofascial pain syndromes are among some of the most common acute and chronic pain conditions. Many interventional procedures can be performed in both an acute and chronic pain setting to address myofascial pain syndromes. Trigger point injections can be performed with or without imaging guidance such as fluoroscopy and ultrasound; however, the use of imaging in years past has been recommended to improve patient outcome and safety. Injections can be performed using no injectate (dry needling), or can involve the administration of local anesthetics, botulinum toxin, or corticosteroids.

A Systematic Review and Meta-Analysis of Efficacy of Botulinum Toxin A for Neuropathic Pain

We performed a systematic review and meta-analysis of randomised controlled trials (RCTs) conducted from January 2005 to June 2021 to update the evidence of Botulinum toxin A (BoNT-A) in neuropathic pain (NP) in addition to quality of life (QOL), mental health, and sleep outcomes. We conducted a Cochrane Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria analysis of RCTs from the following data sources: EMBASE, CINAHL, WHO International Clinical Trial Registry Platform, ClinicalTrials.gov, Cochrane database, Cochrane Clinical Trial Register, Australia New Zealand Clinical Trials Registry, and EU Clinical Trials Register. Meta-analysis of 17 studies showed a mean final VAS reduction in pain in the intervention group of 2.59 units (95% confidence interval: 1.79, 3.38) greater than the mean for the placebo group. The overall mean difference for sleep, Hospital Anxiety and Depression Scale (HADS) anxiety, HADS depression, and QOL mental and physical sub-scales were, respectively, 1.10 (95% CI: -1.71, 3.90), 1.41 (95% CI: -0.61, 3.43), -0.16 (95% CI: -1.95, 1.63), 0.85 (95% CI: -1.85, 3.56), and -0.71 (95% CI: -3.39, 1.97), indicating no significance. BoNT-A is effective for NP; however, small-scale RCTs to date have been limited in evidence. The reasons for this are discussed, and methods for future RCTs are developed to establish BoNT-A as the first-line agent.

Retrospective study of the clinical effect of incobotulinumtoxinA for the management of myofascial pain syndrome in refractory patients

The aim was to evaluate the effectiveness and safety of IncobotulinumtoxinA (IncoA) for the management of myofascial pain syndrome (MPS) in refractory patients. This single-center, observational, retrospective study includes 37 patients. The pain reduction was 4.7 points (95%CI: 5.6 to -3.8) from baseline to one-month post-injection (using a 10-point visual analogue scale). Only 18.9% experienced mild adverse events. In conclusion, IncoA is an effective and safe alternative for the treatment of MPS in refractory patients.

The Use of Botulinum Toxin A as an Adjunctive Therapy in the Management of Chronic Musculoskeletal Pain: A Systematic Review with Meta-Analysis

Several studies have investigated the effect of botulinum toxin A (BoNT-A) for managing chronic musculoskeletal pain, bringing contrasting results to the forefront. Thus far, however, there has been no synthesis of evidence on the effect of BoNT-A as an adjunctive treatment within a multimodal approach. Hence, Medline via PubMed, EMBASE, and the Cochrane Library-CENTRAL were searched until November 2020 for randomised controlled trials (RCTs) that investigated the use of BoNT-A as an adjunctive therapy for chronic musculoskeletal pain. The risk of bias (RoB) and the overall quality of the studies were assessed through RoB 2.0 and the GRADE approach, respectively. Meta-analysis was conducted to analyse the pooled results of the six included RCTs. Four were at a low RoB, while two were at a high RoB. The meta-analysis showed that BoNT-A as an adjunctive therapy did not significantly decrease pain compared to the sole use of traditional treatment (SDM -0.89; 95% CI -1.91; 0.12; p = 0.08). Caution should be used when interpreting such results, since the studies displayed very high heterogeneity (I = 94%, p < 0.001). The overall certainty of the evidence was very low. The data retrieved from this systematic review do not support the use of BoNT-A as an adjunctive therapy in treating chronic musculoskeletal pain.

Effect of integrated neuromuscular inhibition technique compared with positional release technique in the management of piriformis syndrome

CONTEXT

Studies have indicated that the muscle energy technique (MET) and the positional release technique (PRT) are effective in the management of piriformis syndrome (PS); however, evidence is scarce regarding the combination of these techniques in the form of an integrated neuromuscular inhibition technique (INIT) in the management of individuals with PS. Although a previous trial investigated the effect of INIT for PS, that study did not integrate Ruddy's reciprocal antagonist facilitation (RRAF) method into the INIT protocol, nor did the authors diagnose PS according to established criteria.

OBJECTIVES

To examine the effects of INIT with integrated RRAF compared with PRT in the management of patients diagnosed with PS.

METHODS

This study was designed as a single blind randomized clinical trial in which participants diagnosed with PS were randomly allocated into INIT and PRT groups. Each group attended two treatment sessions per week for 8 weeks. Patients in the INIT group received a protocol in which the patient's tender point or trigger point was palpated in the belly of the piriformis approximately halfway between the inferior lateral angle of the sacrum and the greater trochanter, at which point the therapist applied an intermittent or sustained pressure and maintained the pressure for 20-60 seconds (depending on the participant's response to pain reduction). For INIT patients, that protocol was also followed by RRAF, a method in which a patient introduces a series of tiny/miniature contractions or efforts (20 times per 10 seconds) against a therapist's resistance. Patients in the PRT group were treated by palpating the same trigger point described in the INIT group, followed by application of light pressure at the location of the trigger point, which was maintained the pressure for 2 minutes or until the pain subsided (determined by asking the participant to report a pain score using a visual analog scale at 30 second intervals). For both groups, three repetitions of the INIT or PRT treatment were performed over 10 minutes at each clinical visit. Additionally, each group also received stretching exercises immediately after the INIT or PRT treatment session. Each participant was assessed at baseline, immediately posttreatment, and at 4 months posttreatment for pain, sciatica, functional mobility, quality of life, hip abduction, and internal rotation. A repeated measures analysis of variance (ANOVA) of within-between group interactions was used to analyze the treatment effect.

RESULTS

Forty eight participants (age range, 25-47 years; mean age ± standard deviation, 32.81 ± 3.27 years) were randomized into the INIT and PRT groups, with 24 participants in each group. No significant between-group differences (p>0.05) were observed in the baseline demographic and clinical variables of the participants. A repeated-measures ANOVA indicated that there was a significant time effect for all outcomes, with a significant interaction between time and intervention (p<0.001). The Bonferroni post hoc analyses of time and intervention effects indicated that the INIT group improved significantly compared with the PRT group in all outcomes (p<0.05) immediately posttreatment and at the 4 months follow up period.

CONCLUSIONS

INIT was more effective than PRT in the management of individuals with PS. It should be noted the significant improvement achieved in both the groups may have also been contributed to by the stretching exercises that were used as adjunct therapies by both groups.

Effects of ELDOA and post-facilitation stretching technique on pain and functional performance in patients with piriformis syndrome: A randomized controlled trial

BACKGROUND

Piriformis syndrome (PS) is a neuro-muscular condition, which is often underdiagnosed in clinical settings. This study will determine the effects of myofascial stretching Elongation Longitudinaux Avec Decoaption Osteo Articulaire (ELDOA) and post-facilitation stretching of the piriformis muscle in patients with PS.

OBJECTIVE

We aimed to compare the effects of ELDOA and post-facilitation stretching of the piriformis muscle on pain, muscle length and functional performance in patients with PS.

METHODS

A randomized clinical trial was conducted with 40 PS patients including both males and females, between the ages of 30-70. Patients were randomly assigned to the ELDOA or post-facilitation group after assessments with the Numeric Pain Rating Scale (NPRS), Lower Extremity Functional Scale (LEFS), Piriformis Length Test and Straight Leg Raise (SLR). The assessments were done at baseline and at the end of the sixth week of treatment.

RESULTS

The patients treated with ELDOA demonstrated significant improvement in pain (pre = 7.00 ± 2.75, post = 3.00 ± 1.75), piriformis length (pre = 27.6 ± 5.54, post = 36.8 ± 3.13), SLR (pre = 36.40 ± 7.24, post = 67.5 ± 8.36) and LEFS (pre = 26.90 ± 12.24, post = 58.10 ± 8.62), as compared with the group treated with post-facilitation stretching: pain: pre = 6.00 ± 1.00, post = 2.00 ± 1.50; piriformis length: pre = 28.55 ± 4.03, post = 38.8 ± 2.70; SLR: pre = 40.60 ± 7.48, post = 74.25 ± 5.19, and LEFS: pre = 25.20 ± 7.66, post = 66.30 ± 7.27).

CONCLUSION

It can be concluded that the post-facilitation stretching technique shows more improvement in pain, muscle length, SLR, and LEFS in patients with PS as compared to ELDOA.

Surgical and Non-surgical Treatment Options for Piriformis Syndrome: A Literature Review

Context

Piriformis syndrome is a solely clinical diagnosis that often eludes the practitioner and goes underdiagnosed. PS is a pain syndrome and for those it affects, causes persistent pain and limits daily activity and work capacity. It is a form of deep gluteal syndrome that needs to be considered on the differential of low back pain as it comprises between 0.3% - 6% of all low back pain cases and is frequently underdiagnosed. Piriformis syndrome may be primary due anatomic anomalies or secondary, though the majority of cases are secondary to some insult. The objective of this manuscript is to provide a description of the epidemiology and presentation of piriformis as well as both non-operative and operative treatment options. We review all of the recent clinical evidence regarding the aforementioned therapies.

Evidence Acquisition

Literature searches were performed using the below MeSH Terms using Mendeley version 1.19.4. Search fields were varied until further searches revealed no new articles. All articles were screened by title and abstract. Decision was made to include an article based on its relevance and the list of final articles was approved three of the authors. This included reading the entirety of the article. Any question regarding the inclusion of an article was discussed by all authors until an agreement was reached.

Results

Medical management and physical therapy show some promise; however, when conservative treatment fails minimally invasive methods such as steroid injections, botulinum toxin injections, dry needling are all efficacious and there is substantial clinical evidence regarding these therapies. In those patients in which minimally invasive techniques do not result in an adequate relief of pain and return of function, endoscopic release can be considered. Endoscopic release is far superior to open release of the piriformis syndrome given the higher success and lower rate of complications.

Conclusions

Piriformis syndrome is an important differential diagnosis in the work up of lower back pain and should not be ruled out with proper examination and testing. Clinicians should consider medical management and conservative management in the initial treatment plan for piriformis syndrome. There are many options within the conservative management and the literature shows much promise regarding these. Physical therapy, steroid injections, botulinum toxin injections, and dry needling are all potentially effective therapies with few adverse effects. Surgical options remain as gold standard, but only when conservative management has failed and the symptoms are significant to affect daily living activities. Endoscopic decompression of the sciatic nerve with or without release of the piriformis muscle has a reported high likelihood of success and a low complication rate. Current literature supports the preference of the endoscopic approach over the open approach due to improved outcomes and decreased complications. Further research is to well define the metrics for the diagnosis of piriformis syndrome and may include a need to develop diagnostic criteria.

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.

A clinical approach of neuropathic pain in piriformis syndrome: case presentation and rehabilitation particularities

Piriformis syndrome is a rare cause of sciatica and buttock pain and is usually considered as a diagnosis of exclusion for patients with a history of trauma. It usually presents without abnormalities regarding sensory and motor functions and tends to have a favorable evolution with pharmacological treatment. We present the case of a patient with posttraumatic piriformis syndrome who came to our department with significant pain and muscle weakness. The diagnosis was confirmed using clinical tests, imaging techniques and electroneurography. The patient did not respond to pharmacologic treatment alone and therefore surgery was performed. Surgery along with pharmacological treatment, complementary pain treatment and physical rehabilitation provided a favorable outcome. Keywords: neurology, rehabilitation, piriformis syndrome, deep gluteal syndrome, traumatic neuropathy, neuropathic pain,

Botulinum Neurotoxin for the Treatment of Neuropathic Pain

Botulinum neurotoxin is widely used for the treatment of central and peripherical neurological conditions. Initially used to treat strabismus, over the years its use has been expanded also to spasticity and other neurological disorders. This review summarizes the evidence from the published literature regarding its effect on neuropathic pain. Almost all investigations were performed using onabotulinum toxin type A (BoNT/A). Most studies provided positive results, even though toxin formulation, dose, dilution, injection techniques, and sites are heterogeneous across studies. Future larger, high-quality, specifically designed clinical trials are warranted to confirm botulinum neurotoxin efficacy in neuropathic pain.

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.

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.

Feasibility and Reliability of an Ultrasound Examination to Diagnose Piriformis Syndrome

OBJECTIVE

We explored the diagnostic performance of ultrasound examinations in the diagnosis of piriformis syndrome (PS).

METHODS

In our single-center retrospective study, 52 patients with a diagnosis of PS and 50 healthy volunteers were enrolled to undergo ultrasound examination of the piriformis and sciatic nerve. The thicknesses of the piriformis and the diameter of the sciatic nerve were measured to compare the differences between the patients with PS and healthy volunteers. The diagnostic performance of ultrasound examinations was assessed by constructing a receiver operating characteristic curve and calculating the area under the curve.

RESULTS

In patients with PS, the piriformis and sciatic nerve were enlarged on the abnormal side compared with the asymptomatic side, accompanied by a decreased echo intensity and an unclear perineurium. In addition, the piriformis thickness and sciatic nerve diameter of those with PS were significantly greater than were those of the healthy volunteers. The diagnostic performance of ultrasonography was significant. The area under the receiver operating characteristic curve for piriformis thickness and sciatic nerve diameter to discriminate between the abnormal and asymptomatic sides was 0.778 and 0.871, respectively.

CONCLUSION

Ultrasound examinations can assist in the clinical diagnosis of PS and have the potential to be an alternative method for the diagnosis of PS for most musculoskeletal clinicians.

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.

Gluteus medius muscle decompression for buttock pain: a case-series analysis

BACKGROUND

The causes of low back and buttock pain are variable. Elsewhere, we presented a surgical technical note addressing the gluteus medius muscle (GMeM) pain that elicited buttock pain treatable by surgical decompression. Here, we report minimum 2-year surgical outcomes of GMeM decompression for intractable buttock pain.

METHODS

Between January 2014 and December 2015, we surgically treated 55 consecutive patients with a GMeM pain. Of these, 39 were followed for at least 2 years; they were included in this study. Their average age was 69.2 years; 17 were men and 22 were women. The affected side was unilateral in 24 patients and bilateral in the other 15 (total 54 sites). The mean follow-up period was 40.0 months (range 25-50 months). The severity of pre- and post-treatment pain was recorded on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ).

RESULTS

Of the 39 patients, 35 also presented with leg symptoms. They were exacerbated by walking in all 39 patients and by prolonged sitting in 33 patients; 19 had a past history of lumbar surgery and 4 manifested failed back surgery syndrome. Repeat surgery for wider decompression was performed in 5 patients due to pain recurrence 15.8 months after the first operation. At the last follow-up, the symptoms were significantly improved; the average NRS fell from 7.4 to 2.1 and the RDQ score from 10.5 to 3.3 (p < 0.05).

CONCLUSIONS

When diagnostic criteria are met, GMeM decompression under local anesthesia is a useful treatment for intractable buttock pain.

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.

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.

Botulinum toxin-A for the treatment of neuralgia: a systematic review and meta-analysis

AIM

This meta-analysis was performed to evaluate the efficacy and safety of botulinum toxin-A (BTX-A) for the treatment of neuralgia.

METHODS

We searched PubMed, EMBASE, and Cochrane databases to identify randomized controlled trials (RCTs) comparing BTX-A treatment with saline for alleviating neuropathic pain. Primary outcome measures were pain scores up to 24 weeks after treatment. Secondary outcomes were hours of sleep, Short Form-36 (SF-36) life quality questionnaire, and adverse events. We used Review Manager 5.3 for the data analyses.

RESULTS

Twelve RCTs were included (n=495). Pain scores in the BTX-A group were significantly lower compared to the saline group at 4 weeks (mean difference [MD] =-1.64, 95% CI [-3.21, -0.07], P=0.04), 12 weeks (MD =-1.49, 95% CI [-2.05, -0.93], P<0.00001), and 24 weeks (MD =-1.61, 95% CI [-2.81, -0.40], P=0.009). There were no significant differences in hours of sleep, SF-36 questionnaire, or the incidence of injection pain or hematoma between the two groups. No serious adverse events associated with BTX-A were noted. Fourteen out of 108 patients (12.9%) with trigeminal neuralgia experienced mild facial asymmetry after the BTX-A treatment.

CONCLUSION

Based on the current evidence, BTX-A may be an effective and safe option for the treatment of neuralgia. Due to the limited number of patients included in this meta-analysis, more trials are still needed to confirm these results.