Piriformis Syndrome

Sciatic Nerve and Its Anatomical Variations: In-Depth Understanding Acquired During Dissection Classes

Knowledge of anatomical variability is extremely important in order to better understand the etiology of pain, if present, or to avoid iatrogenic consequences. Sometimes the anatomical "anomalies" have the same anamnesis but different causes. For example, sciatic neuralgia may be caused by a herniated disc or it may have a different origin. The sciatic nerve (SN), also known as the ischial nerve, is the widest in the human body. This huge peripheral nerve originates from the roots of the lumbosacral plexus (L4-S3) and passes through the great sciatic foramen, under the piriformis muscle (PM). However, there is much variability in the pattern of SNs about the muscle, which has been known since the first half of the 20th century. In the present study, we describe six different case reports of anatomical variations of the SN and its interplay with the PM. The observations were made during dissection classes at the ICLO Teaching and Research Centre (Verona, Italy), on both male and female cadavers aged between 58 and 84 years. The SN was reported as a single and divided nerve into the tibial nerve (TN) and the common peroneal nerve (CPN), passing alone above, below, or between the PM. However, the two parts of the SN may also interact with the PM in different ways, adding to the anatomical variability. A thorough knowledge of the anatomical variations in any part of the human body is extremely important. The various techniques used, from imaging to autopsy or surgery, are also useful in the SN pathway. Thus, the anatomical features and the understanding of each variation are useful for a correct approach that can lead to an effective and correct treatment with a favorable outcome.

Diagnostic Approach to Lower Limb Entrapment Neuropathies: A Narrative Literature Review

Entrapment neuropathies of the lower limb are a misunderstood and underdiagnosed group of disorders, characterized by pain and dysesthesia, muscular weakness, and specific provoking movements on physical examination. The most frequent of these syndromes encountered in clinical practice are fibular nerve entrapment, proximal tibial neuropathy, sural nerve neuropathy, deep gluteal syndrome or sciatic nerve entrapment, and lateral femoral cutaneous nerve entrapment, also known as meralgia paresthetica. These are commonly mistaken for lumbar plexopathies, radiculopathies, and musculotendinous diseases, which appear even more frequently and have overlapping clinical presentations. A comprehensive anamnesis, physical examination, and electrodiagnostic studies should help clarify the diagnosis. If the diagnosis is still unclear or a secondary cause of entrapment is suspected, magnetic resonance neurography, MRI, or ultrasonography should be conducted to clarify the etiology, rule out other diseases, and confirm the diagnosis. The aim of this narrative review was to help clinicians gain familiarity with this disease, with an increase in diagnostic confidence, leading to early diagnosis of nerve damage and prevention of muscle atrophy. We reviewed the epidemiology, anatomy, pathophysiology, etiology, clinical presentation, and EDX technique and interpretation of the entrapment neuropathies of the lower limb, using articles published from 1970 to 2022 included in the Pubmed, MEDLINE, Cochrane Library, Google Scholar, EMBASE, Web of Science, and Scopus databases.

The Invasive Management of Pain: Diagnosis and New Treatment Options

Both the diagnosis and treatment of pain are evolving, especially in interventional approaches. Diagnosis of low back pain combines old and new methodologies, in particular, it involves an expanded role for ultrasound. While low back pain is a common complaint, there are many etiologies to the condition which must be explored before a final diagnosis can be made and treatment planned. Tumors and infections are rarely involved in low back pain but should be ruled out in the initial phase itself since failing to address them early can have devastating consequences. Some invasive treatments seem promising in the management of low back pain. Treating musculoskeletal pain with regenerative medicine, such as platelet-rich plasma, holds great promise. Autologous blood products are safe and may help stimulate the body's own responses for regeneration. The so-called "orthobiologics" play a role in sports medicine and the treatment of musculoskeletal pain. Neuromodulation, especially spinal cord stimulation, is undergoing a renaissance with new waveforms, devices, and a greater albeit incomplete understanding of its mechanisms of action. Spinal cord stimulation is not a first-line therapy and not all patients or all back problems respond to this treatment. Nevertheless, the therapy can be safe, effective, and cost-effective with appropriate patient selection. Radiofrequency ablation of nerves in the form of neurotomy can be effective in reducing the pain of osteoarthritis. These procedures, including the newer cooled radiofrequency neurotomy, can restore function, reduce pain, and may potentially have an opioid-sparing effect. Technical expertise in nerve and anatomy is needed for the use of this technique. This review article aims to provide updated information on some invasive intervention techniques in pain management.

Association of Piriformis Thickness, Hip Muscle Strength, and Low Back Pain Patients with and without Piriformis Syndrome in Malaysia

Low back pain is a serious threat to human health and the illness jeopardizes the human workforce and pressurizes the health system in the community. Low back pain might be related to piriformis syndrome (PS), which is a disorder presented as muscular spasm and hypertrophy that is strongly associated with piriformis thickness. Nevertheless, the relationship between piriformis thickness and morphological and functional changes of the gluteal muscles in PS remains unclear. This study aimed to investigate the association between the thickness, strength, and activation of piriformis and gluteus muscles (maximus and medius) among low back pain (LBP) patients with and without PS. This is a case-control study conducted at HSNZ and UiTM from 2019-2020. A total number of 91 participants (LBP + PS (n = 36), LBP - PS (n = 24), and healthy (n = 31)) were recruited in this study. Negative radiography, specific symptoms, and a positive PS test were applied for PS diagnoses. The thickness, strength, and activation of piriformis and gluteus muscles were measured using ultrasonography (USG) and a surface electromyogram, respectively. Resultantly, the one-way ANOVA test demonstrated no significant difference in piriformis thickness between LBP + PS and LBP - PS (p > 0.01). Piriformis thickness was inversely correlated with gluteus maximus strength (r = -0.4, p < 0.05) and positively correlated with gluteus medius activation (r = 0.48, p < 0.01) in LBP + PS. Stepwise linear regression for LBP + PS revealed a significant association between piriformis thickness and gluteus maximus strength (R = -0.34, accounted for 11% of the variance) and gluteus medius activation in prone lying with the hip in an externally rotated, abducted, and extended (ERABEX) position (R = 0.43, accounted for 23% of the variance). With the adjustment of age and gender, piriformis thickness, gluteus maximus strength, and gluteus medius activation in prone lying with hip ERABEX demonstrated a significant association, but no independent effect of age and gender was detected within the range. Meanwhile, a significant association between piriformis thickness and gluteus maximus thickness was observed (R = 0.44, accounted for 19% of the variance) in the LBP - PS group. These findings may assist to elucidate the actions and functions of piriformis and gluteus muscle in LBP with and without PS.

Acute Obturator Externus Injury in Professional Soccer Players: A Case Series

When patients present with hip or groin pain, proximal quadriceps or adductor injuries are often initially suspected. In this case report, however, we present three cases of professional soccer players who were found to have obturator externus injury. A 30-year-old player and a 24-year-old player complained of pain in the left side after long distance shooting during an in-season training session and a match, respectively. Another 24-year-old player complained of pain in the right side after long distance passing during a preseason training session. On physical examination, active hip external rotation and passive hip internal rotation and extension elicited pain in all three players. All three players underwent magnetic resonance imaging (MRI) which found obturator externus grade II injuries for two players and grade I injury for one player. Rehabilitation protocols included relative rest, cryotherapy, and electrotherapy over a period of one week. All patients were able to return to play after 10 days. Correct identification of obturator externus injury afforded our players a favorable prognosis and a relatively quick return-to-sport compared with quadricep or adductor injury.

The Hip-Spine Connection: How to Differentiate Hip Conditions From Spine Pathology

Practitioners treating spine pathology commonly encounter patients with hip pain. These patients frequently manifest groin, buttock, trochanteric, or knee pain. Complex biomechanical interaction between the axial and the appendicular skeleton may result in compensatory adaptation. Cross-innervation of the hip and surrounding tissues may make diagnosis of the primary source difficult, leading to delayed diagnosis. This review elucidates the interaction between the hip and the spine and can assist clinicians in recognizing the hip as a potential source of pain. Diagnostic guidelines enabling a streamlined workup of patients presenting with confusing symptoms related to the hip that masquerade as a spine disorder are presented. [Orthopedics. 2021;44(6):e699-e706.].

Intrapelvic entrapment of sacral nerve roots by abnormal bundles of the piriformis muscle: description of an extra-spinal cause of sciatica and pudendal neuralgia

Piriformis syndrome is a well-known extra-spinal cause of sciatica characterized by the entrapment of the sciatic nerve by variant bundles of the piriformis muscles in the deep gluteal space. In this case series, we describe the entrapment of intrapelvic portions of the sacral nerve roots by a variant bundle of the piriformis muscle originating medially to the sacral foramina, the surgical technique for the laparoscopic treatment of this condition, and the outcomes of the first eight cases treated with this technique. Five female and three male patients presenting with sciatica, pudendal pain and lower urinary tract symptoms underwent a laparoscopic exploration of the intrapelvic portion of the sacral nerve roots and transection of the abnormal piriformis bundle. Surgical technique is demonstrated in the Supplementary Video. Clinical success was achieved in seven of the eight patients, with a reduction of pain numeric rating scale from 8.5 (±1.2; 7-10) pre-operatively to 2.1 (±2.6; 0-7), 1-year following surgery. In conclusion, entrapment of intrapelvic portions of the sacral nerve roots by variant bundles of the piriformis originating medially to the sacral foramina are an extraspinal cause of sciatica, which can be treated though a laparoscopic approach.

Laparoscopic surgical approach for the treatment of piriformis syndrome: Intrapelvic decompression technique

Introduction:

Piriformis syndrome is an uncommon disease resulting from the piriformis muscle’s compression of the sciatic nerve. Pain and numbness in the buttocks and down the leg are the most common symptoms. This study analyzes the laparoscopic surgical treatment of piriformis syndrome.

Methods:

We report three cases of piriformis syndrome diagnosed in our hospital. The first case was a 40 years old woman with a 7-year history of intermittent low back pain and sciatica on her right side. Hyperesthesia and cutaneous allodynia were observed in the right sciatic nerve dermatome. The second case was a 30 years old woman with a 2-year history of sciatica on her left side. The third case was a 30 years old woman with a 2-year history of sciatica on her right side. All the patients underwent laparoscopic decompression surgery, which was performed to release the sciatic nerve or sacral nerve roots.

Results:

The patients were reexamined at the postoperative 3rd and 6th months. Their visual analog scale (VAS) scores were found to be decreased from 10/10, 9/10, and 7/10 to 0/10, 1/10, and 0/10, respectively.

Conclusion:

Due to the very few cases in the literature, pelvic piriformis syndrome is an exclusively clinical diagnosis. If the sciatica is refractory to conservative treatments, laparoscopic exploration and decompression surgery of the pelvic nerves and piriformis muscle could be an option.

Acute Groin Pain Syndrome Due to Internal Obturator Muscle Injury in a Professional Football Player

Traumatic groin pain syndrome is the result of an acute trauma, usually an indirect muscle injury (i.e., an overstretching of the muscle fibers). The most affected muscles in traumatic groin pain syndrome are rectus abdominis, adductors, and iliopsoas. The internal obturator muscle lesion is very rare. The internal obturator muscle externally rotates the thigh and contributes to the stabilization of the hip joint and its indirect injury may cause the onset of traumatic groin pain syndrome. This case report describes a rare indirect injury of internal obturator in a 29-year-old professional male soccer player.

Multimodal treatment including lumbar facet joint denervation for severe low back pain in patients with neuromuscular disorders

BACKGROUND

Severe low back pain (LBP) is an occasional complaint in patients with neuromuscular disorders (NMDs). Accurate diagnosis and treatment are required to manage LBP; however, the precise pathophysiology differs for each patient. This study aimed to evaluate the efficacy of lumbar facet joint denervation (FJD) and adjunctive modalities in the treatment of LBP in patients with NMD-associated kyphoscoliosis.

METHODS

A total of 16 patients (22 sites) with NMD (bilateral, n = 6; unilateral, n = 10) and LBP treated with lumbar FJD were evaluated. The patients were divided into two groups: those treated with FJD alone (group 1) and those treated with multimodal treatment, including FJD along with radiofrequency ablation for sacroiliac joint pain, piriform muscle block, botulinum toxin injection into the paraspinal muscles, spinal cord stimulation, or any of their combinations (group 2). All patients were followed up for 48 weeks postoperatively. The two groups were compared with respect to the duration required for improvements in LBP by more than 50% (numerical rating scale ≤ 5).

RESULTS

There was no significant difference between the groups regarding the age, duration since the onset of Parkinson's syndrome, and radiographic analysis. The effective period of improved pain was greater in group 2 than in group 1 (30.7 vs. 8.4 weeks, P < 0.01).

CONCLUSIONS

Multimodal treatment including FJD is safe and relatively effective in patients with NMD-associated kyphoscoliosis. Hence, it is a potential substitute for conventional spinal fixation surgery, which has a higher risk of complications.

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.

Piriformis syndrome: pain response outcomes following CT-guided injection and incremental value of botulinum toxin injection

PURPOSE

Piriformis syndrome is a common pain condition affecting the buttock and posterior hip with or without radiation to the leg, and management of the condition involves many treatments. In this study, we hypothesize that a CT-guided injection with botulinum toxin is more effective in providing pain relief than a CT-guided injection without Botox.

METHODS

Overall, 97 consecutive patients with piriformis syndrome presented for a CT-guided injection of the piriformis muscle and perineural injection of the sciatic nerve. After the injection, the patients received a visual analog scale pain log to record their pain level until the follow-up appointment. P values of less than 0.2 were considered as confounder and adjusted by inverse probability of treatment weighting (IPTW) via propensity score. The effect of botulinum toxin on 48-hour response and duration of response was tested using weighted chi-square test and weighted Kaplan-Meier analysis.

RESULTS

There was a total of 97 patients in the study, and 111 injections, as some patients had bilateral injections. Patients in the Botox group had more 48-hour response than patients in the non-botulinum toxin group (P < 0.001 with IPTW, P = 0.005 without IPTW). Median pain-free survival was 30 days for Botox group and 1 day for non-Botox group (P = 0.059 with IPTW, P = 0.10 without IPTW).

CONCLUSION

CT-guided injections with botulinum toxin for patients with piriformis syndrome are more likely to lead to a positive response and a longer duration of response than patients who receive a CT-guided injection without botulinum toxin. We hope that this study facilitates future prospective randomized blind trials for patients with suspected piriformis syndrome.

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,

Complete resolution of recurrent piriformis syndrome after piriformis resection with 3 years' follow up: A case report

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Some of piriformis syndrome intractable with conservative treatment.

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Surgery was indicated for intractable piriformis syndrome.

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Piriformis resection can be a feasible option for intractable piriformis syndrome.

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Piriformis resection decrease visual analog scale in intractable piriformis syndrome.

Introduction

Piriformis syndrome (PS) is an uncommon neuromuscular condition characterized by buttock pain radiating to the leg. Although the goal of PS treatment is symptom relief, it is difficult in some patients using conservative treatment alone.

Presentation of case

A 72-year-old male underwent piriformis resection after failed sequential steroid injection of the piriformis. The patient ultimately underwent surgery for resection of the piriformis muscle and experienced satisfactory pain relief (pain reduction > 75% according to visual analog scale for at least 12 months) following surgery and in the 3-year follow-up period.

Discussion

Conservative treatment is first-choice treatment for managing PS. Surgery was indicated when the patient did not achieve satisfactory pain relief with conservative treatment. Surgical resection of the piriformis muscle has been shown to be effective and feasible.

Conclusion

Piriformis resection is effective and can be a feasible option for the treatment of PS following failure of appropriate conservative treatment(s).

‘Hand on hip’ sign: A novel screening test and diagnostic tool in piriformis syndrome

Introduction:

Currently there is no gold standard clinical test or investigation available to diagnose piriformis syndrome. We have found a pose used by the patients to describe the pain in the gluteal region in cases of suspected piriformis syndrome. This pose in our study has been described as ‘hand on hip sign’ (HHS). In this study, we aim to assess the significance of this sign in screening of patients with piriformis syndrome.

Materials and methods:

Seventy patients presenting with pain in the gluteal region with radiculopathy between the age group of 18 years and 60 years were included. All patients were asked to locate the site of the pain in the gluteal region. The demonstration of pain by the patients was noted. If the description matched the description of HHS, it was considered to be positive, else it was considered negative. All patients were subjected to four piriformis-specific confirmatory clinical tests. Considering that there is no single confirmatory test, any patient in whom any two piriformis-specific signs were elicited was considered as a case of piriformis syndrome. Using the data, sensitivity, specificity and positive and negative likelihood ratio of the HHS in the diagnosis of piriformis syndrome were calculated. Inter-test comparison was also made using Cohen’s kappa statistic.

Results:

HHS was found to have a sensitivity of 86% and a specificity of 75%. It also has a high positive predictive value of 94% and a positive likelihood ratio of 3.44. Inter-test reliability comparison showed that there was a fair to moderate agreement between HHS and other confirmatory piriformis-specific tests.

Conclusion:

HHS serves as an effective screening test in the identification of piriformis syndrome.

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.

Posterior femoral cutaneous neuropathy in piriformis syndrome: A vascular hypothesis

Piriformis syndrome is described as a neuromuscular condition which occurs when the sciatic nerve is compressed and/or irritated by the piriformis muscle. It is characterized by acute tenderness in the buttock with sciatica-like pain radiating into the posterior aspect of the thigh, leg, and foot. The neurogenic leg and foot pain experienced with this condition is consistent with involvement of the sciatic nerve. However, the posterior thigh pain associated with piriformis syndrome is due to involvement of the posterior femoral cutaneous nerve (i.e., posterior cutaneous nerve of the thigh), which is a branch of the sacral plexus independent of the sciatic nerve. This nerve is rarely mentioned relative to piriformis syndrome even though posterior thigh pain is more prevalent in patients than leg and foot pain. In the few instances when the posterior femoral cutaneous nerve is referenced relative to piriformis syndrome the neuralgic signs associated with it are attributed to compression by piriformis. Yet, given the dramatic size difference between the sciatic and posterior femoral cutaneous nerves one would expect direct piriformis compression to impact the sciatic nerve first and produce leg/foot pain at a far greater frequency than posterior thigh pain. However, the opposite is seen in the literature, which raises the question, what underlying mechanism is responsible for this phenomenon? It is hypothesized that the prevalence of posterior femoral cutaneous nerve involvement in piriformis syndrome is due to compression of the inferior gluteal vein by a hypertrophied piriformis muscle.

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.

Sciatic Nerve Variants in Patients Diagnosed With Sciatica: Is There a Correlation?

PURPOSE

Compression of the sciatic nerve in its path along the piriformis muscle can produce sciatica-like symptoms. There are 6 predominant types of sciatic nerve variations with type 1 being the most common (84.2%), followed by type 2 (13.9%). However, there is scarce literature on the prevalence of sciatic nerve variation in those diagnosed with sciatica.

MATERIALS AND METHODS

The charts of 95 patients clinically diagnosed with sciatica who had a magnetic resonance imaging of the pelvis/hip were retrospectively studied. All patients had T1-weighted axial, coronal, and sagittal images. Magnetic resonance imagings were interpreted separately by 2 board-certified fellowship-trained musculoskeletal radiologists to identify the sciatic nerve variant.

RESULTS

Seven cases were excluded because of inadequate imaging. Of the remaining 88 patients, 5 had bilateral sciatica resulting in a sample size of 93 limbs. Fifty-two (55.9%) had type 1 sciatic nerve anatomy, 39 (41.9%) had type 2, and 2 (2.2%) had type 3. The proportions of type 1 and 2 variations were significantly different from the normal distribution (P < 0.001), whereas type 3, 4, 5, and 6 variants were not (P = 1.00).

CONCLUSIONS

There is strong statistical significance regarding the relationship between sciatic nerve variation and the clinical diagnosis of sciatica. Preoperative magnetic resonance imaging can be considered in sciatica patients to prevent iatrogenic injury in pelvic surgery.

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.

Case Report: Canine Strain– and Study Condition–Dependent Formation of Renaut Bodies in Sciatic Nerves of Beagle Dogs

Two beagle dog strains were used in a 14-day intrathecal infusion study for a small molecule test article. A moderate number of Renaut bodies (RBs) were observed in the sciatic nerves of control and test article–treated adult animals as early as 1 day after test article infusion (ie, 5 days after catheter implantation in the lumbar cistern). In most cases, the sciatic nerve was affected unilaterally, apparently in association with extended lateral recumbency on one side. The lighter beagle strain (Marshall), and especially the females (which weighed less than age-matched Marshall males), developed more RBs. In contrast, neither females nor males of the larger strain (Harlan) developed any nerve lesions. These data support the hypothesis that RBs develop following mechanical stress to sciatic nerves, suggest that this change may develop fairly quickly following an insult, and demonstrate that different dog strains exhibit strain-specific nerve changes.

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.

Research on Roles of Mongolian Medical Warm Acupuncture in Inhibiting p38 MAPK Activation and Apoptosis of Nucleus Pulposus Cells

Background

Mongolian medical warm acupuncture has a desirable therapeutic effect on sciatica. Apoptosis of the nucleus pulposus cells is considered to play an important role in sciatica. Evidence has demonstrated that oxidative stress and its induced activation of the signaling pathways play important roles in sciatica. However, further research is expected to reveal whether Mongolian medical warm acupuncture can inhibit the apoptosis of nucleus pulposus cells and oxidative stress.

Objective

To study the effect of the p38 MAPK pathway activated by the generated ROS on apoptosis and the expression of the genes related to the balance of the extracellular matrix metabolism during treatment of sciatica with Mongolian medical warm acupuncture.

Method

The volume of the active oxygen generated in the nucleus pulposus cells was detected following intervention of Mongolian medical warm acupuncture. The p38 MAPK phosphorylation level was detected with Western blot. The genes are related to the metabolism of the nucleus pulposus extracellular matrix.

Result

Mongolian medical warm acupuncture reduced the active oxygen within the nucleus pulposus cells and inhibited the activation of the p38 MAPK pathway (P=0.013). Meanwhile, it upregulated the gene expression of Type II collagen, aggrecan, Sox-9, and tissue matrix metalloproteinase reagent 1 (P-0.015; P=0.025; P=0.031; P=0.045) and downregulated the gene expression of matrix metalloproteinase 3 (P=0.015).

Conclusion

Mongolian medical warm acupuncture may inhibit apoptosis of nucleus pulposus cells and activation of the extracellular matrix decomposition metabolism pathway and promote its anabolism. This process may rely on the oxidative stress matrix of the p38 MAPK pathway.

Injuries of the obturator muscles in professional soccer players

PURPOSE

Obturator externus and internus muscular tears are uncommon injuries. Only a few case reports exist, mainly in high-level athletes. Our aim is to describe a series of obturator externus and internus muscular tears in professional soccer players.

METHODS

Injury data from four teams from the First Division of the Spanish Soccer League were collected over a total of four seasons. Any soccer player who sustained an injury to either the obturator externus or internus identified on magnetic resonance (MRI) was included. All injured players were treated non-operatively with a goal of returning to play as fast as possible.

RESULTS

Sixteen players sustained injuries to the obturator externus and internus during matches or training sessions. The main complaint was anterior hip pain with a physical examination showing pain during internal rotation or external rotation of the flexed hip. The MRI documented 12 muscular tears of the obturator externus, and 4 muscular tears of the obturator internus. All injuries were treated conservatively based on physical therapy, analgesic medications, and underwent a symptoms-based rehabilitation protocol. Mean return to play was 11.5  ±  8.8 days.

CONCLUSION

Although uncommon, tears of the obturator externus and internus occur in professional soccer players. The MRI scan was essential to the location, classification, and evaluation of the injury size. The clinical relevance of our investigation is based on the relatively benign prognosis of these injuries.

LEVEL OF EVIDENCE

IV.

Rehabilitative ultrasound imaging of the bilateral intrinsic plantar muscles and fascia in post-stroke survivors with hemiparesis: A case-control study

Purpose: The study main aim was to compare the cross-sectional area (CSA) and thickness of the plantar muscles and fascia in the hemiparesis and contralateral feet of poststroke survivors with respect to healthy feet of matched controls. Methods: A case-control observational study was performed using B-mode rehabilitative ultrasound imaging. A convenience sampling method was used to select 60 feet. The sample was divided into 20 feet ipsilateral and 20 feet contralateral to the hemiparesis lower limb from poststroke survivors, as well as 20 healthy feet from matched controls. The CSA and thickness of the abductor hallucis, flexor digitorum brevis and flexor hallucis brevis, as well as the thickness for the posterior, middle and anterior plantar fascia portions were measured. Comparisons and multivariate predictive analyses were carried out for ultrasound measurements. In all analyses, a P-value<.01 with a 99% confidence interval was considered as statistically significant. Results: Statistically significant differences (P<.01) were shown for a flexor hallucis brevis thickness increase as well as middle and anterior plantar fascia thickness decrease of the hemiparesis feet and contralateral feet with respect to the healthy matched control feet. The rest of measurements did not show any statistically significant difference (P>.01). Conclusions: The thickness of the flexor hallucis brevis muscle as well as the middle and anterior plantar fascia portions of the hemiparesis and contralateral feet from poststroke survivors presented morphology changes with respect to the healthy matched control feet.

Ultrasound-Guided Subgluteal Sciatic Nerve Perineural Injection: Report on Safety and Efficacy at a Single Institution

OBJECTIVES

To determine the safety and efficacy of ultrasound (US)-guided subgluteal sciatic nerve injections.

METHODS

A retrospective chart review of US-guided subgluteal sciatic nerve injections at our institution was performed.

RESULTS

Of 221 US-guided subgluteal sciatic nerve injections, 100% achieved technical success, with no postprocedure complications. Sixty-eight percent of patients with follow-up reported symptom relief. Most patients with no relief had suboptimal preprocedure screening.

CONCLUSIONS

With appropriate screening, our technique of US-guided subgluteal sciatic nerve injection is safe and effective.

Accuracy and safety of dry needle placement in the piriformis muscle in cadavers

Objectives

The purpose of this anatomic investigation is to (1) establish accuracy of dry needle placement into the medial third of the piriformis muscle as it exits the pelvis from the greater sciatic notch in unembalmed cadaveric specimens, while avoiding puncture of the sciatic nerve, and (2) establish guidelines for dry needle length selection.

Methods

Dry needles were placed in nineteen unembalmed cadaveric posterior hips. Dissection of the posterior hip musculature was performed to confirm location of the needle. A binary decision (yes/no) was made to determine whether the needle reached the piriformis muscle, went through the piriformis muscle, and/or pierced the sciatic nerve. Additionally, mean adipose tissue thickness, gluteus maximus muscle thickness, and perpendicular distance from the needle to the exiting sciatic nerve were recorded.

Results

The needle reached the medial third of the piriformis in 16 out of 19 hips (84.2% accuracy) and never punctured the sciatic nerve. There was a fair (r = 0.493) and good (r = 0.759) correlation between the needle length and the mean fat thickness for the left and right hips, respectively.

Discussion

A physical therapist was able to use bony landmark palpation to locate the piriformis muscle and use estimated adipose tissue thickness to choose a sufficient needle length to reach the medial third of the piriformis muscle. While the needle placement technique was safe and no sciatic nerve puncture occurred, the proximity of the piriformis muscle to the sciatic nerve warrants caution during needle placement.

Level of Evidence

2c.

[Tendinopathies of the hip : Treatment recommendations according to evidence-based medicine]

Tendinopathies of the hip are a differential diagnostic challenge. The spatial proximity of these structures is challenging and many of the structures are located in very deep positions in an individual-specific manner and are covered by other tissues resulting in difficult accessibility for a clinical examination. Furthermore, the definition of the different syndromes is not consistent in the literature, which makes a comparability and assessment difficult. This article demonstrates the most frequent tendinopathies and associated syndromes with their typical clinical presentation, diagnostics and therapy options. Finally, a critical assessment of these aspects is presented based on the current literature.

Posterior, Lateral, and Anterior Hip Pain Due to Musculoskeletal Origin: A Narrative Literature Review of History, Physical Examination, and Diagnostic Imaging

OBJECTIVE

The purpose of this study was to present a narrative review of the literature of musculoskeletal causes of adult hip pain, with special attention to history, physical examination, and diagnostic imaging.

METHODS

A narrative review of the English medical literature was performed by using the search terms "hip pain" AND "anterior," "lateral," and "posterior." Additionally, specific entities of hip pain or pain referral sources to the hip were searched for. We used the PubMed search engine through January 15, 2016.

RESULTS

Musculoskeletal sources of adult hip pain can be divided into posterior, lateral, and anterior categories. For posterior hip pain, select considerations include lumbar spine and femoroacetabular joint referral, sacroiliac joint pathology, piriformis syndrome, and proximal hamstring tendinopathy. Gluteal tendinopathy and iliotibial band thickening are the most common causes of lateral hip pain. Anterior hip pain is further divided into causes that are intra-articular (ie, labral tear, osteoarthritis, osteonecrosis) and extra-articular (ie, snapping hip and inguinal disruption [athletic pubalgia]). Entrapment neuropathies and myofascial pain should also be considered in each compartment. A limited number of historical features and physical examination tests for evaluation of adult hip pain are supported by the literature and are discussed in this article. Depending on the clinical differential, the gamut of diagnostic imaging modalities recommended for accurate diagnosis include plain film radiography, computed tomography, magnetic resonance imaging, skeletal scintigraphy, and ultrasonography.

CONCLUSIONS

The evaluation of adult hip pain is challenging. Clinicians should consider posterior, lateral, and anterior sources of pain while keeping in mind that these may overlap.

Ultrasound evaluation of intrinsic plantar muscles and fascia in hallux valgus: A case-control study

A cross-sectional area (CSA) and thickness reduction of the abductor hallucis (AbH) is shown in subjects with hallux valgus (HV). To date, other soft-tissue structures have not been researched in relation with HV. The aim of this study was to compare the CSA and thickness of the intrinsic plantar muscles and fascia (PF) between feet with and without HV. Therefore, a cross-sectional and case-control study was performed using B-mode with an iU22 Philips ultrasound system and a 5 to 17-MHz transducer. The CSA and thickness were measured for the AbH, flexor digitorum brevis (FDB) and flexor hallucis brevis (FHB), and also the thickness for the anterior, middle, and posterior PF portions. A convenience sample of 40 feet, 20 with HV and 20 without HV, was recruited from a clinical and research center. A multivariate regression analysis using linear regression was performed to evaluate the ultrasound imaging measurements (α = 0.05). Consequently, statistically significant differences were observed between the groups (P < 0.05) for the AbH and FHB thickness, and CSA reduction, and also the plantar fascia thickness increase in favor of the HV group. On the contrary, the FDB thickness and CSA did not show statistically significant differences (P ≥ 0.05). In conclusion, the CSA and thickness of the AbH and FHB intrinsic plantar muscles are reduced, whereas the thickness of the anterior, middle, and posterior PF portions are increased, in subjects with HV compared with those without HV.

Ultrasound-Guided Peripheral Nerve Injection Techniques

OBJECTIVE

Peripheral nerves are well seen using ultrasound (US) imaging, making US an ideal modality for image-guided nerve injections. This article provides a technical guide for common upper and lower extremity peripheral nerve injections, including the median, ulnar, and radial nerves in the upper extremity and the lateral femoral cutaneous, sciatic, common peroneal, tibial, and sural nerves in the lower extremity.

CONCLUSION

US is an effective modality for use in common upper and lower extremity peripheral nerve injections. With correct technique, peripheral nerve injections can be performed safely and are useful for both diagnostic evaluation of and therapy for peripheral neuropathy.

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.

Bilateral piriformis syndrome in two elite soccer players: Report of two cases

Piriformis syndrome, a relatively rare condition, is described as entrapment of a sciatic nerve at the level of the piriformis muscle. There have been a few reports of bilateral piriformis syndrome in literature. In this study, we present bilateral piriformis syndrome in two professional soccer players from different teams who are symptom free at last follow-up after surgery. In both patients, resting EMG records were read normal, however EMG recording during the activity revealed prolonged H-reflexes. Both patients had no relief from conservative treatment and rehabilitation, therefore surgical treatment was performed. Preoperative mean visual analogue scale (VAS) value was 7, and decreased to 3 at the sixth month follow-up visit and at the longer term follow-up, mean 85months (74-96) it was valued at 1. Both soccer players returned to their active sports lives in the sixth postoperative month. According to Benson's functional evaluation scale, in long-term follow-up, there have been excellent results and both patients resumed their professional carrier for many years (mean 7 years).