Anatomical Proximity Between Sciatic Nerve and Ischial Spine and its Relationship to the Development of Deep Gluteal Pain Syndrome.

OBJECTIVE: Deep gluteal syndrome (DGS) is a medical diagnosis in which the pathoanatomy of the subgluteal space contributes to pain. The growing recognition that gluteal neuropathies can be associated with the presence of a bone-neural conflict with irritation or compression may allow us to shed some light on this pathology. This study aims to determine whether the location of the sciatic nerve (SN) in relation to the ischial spine (IS) contributes to the development of DGS. METHODS: The SN - IS relationship was analyzed based on magnetic resonance imaging (MRI) in 15 surgical patients (SPs), who underwent piriformis release, and in 30 control patients who underwent MRI of the pelvis for reasons unrelated to sciatica. The SN exit from the greater sciatic foramen was classified as either zone A (medial to the IS); zone B (on the IS); or zone C (lateral to the IS). RESULTS: The SN was significantly closer to the IS in SPs than in MRI controls (P = 0.014). When analyzing patients of similar age, SNs in SPs were significantly closer (P = 0.0061) to the IS, and located in zone B significantly more (P = 0.0216) as compared to MRI controls. Patients who underwent surgery for piriformis release showed a significant decrease in pain postoperatively (P < 0.0001). CONCLUSIONS: The results from this study suggest that the relationship between the IS and SN may play a role in the development of DGS. This may also help establish which patients would benefit more from surgical intervention.

Unrepaired Trochanteric Bursae as a Risk Factor for Deep Gluteal Syndrome After Total Hip Arthroplasty: A Prospective Randomized Controlled Trial.

BACKGROUND: The trochanteric bursae are often left unrepaired after total hip arthroplasty (THA) and they retract posteriorly over the muscle belly of the piriformis. Deep gluteal syndrome (DGS) is a multifactorial condition presenting as buttock pain and is attributed to nondiscogenic sciatic nerve irritation or impingement causes. The purpose of this study was to investigate the relationship between bursal repair and incidence of DGS in patients undergoing THA. METHODS: This prospective randomized trial included patients treated with a THA between January and December 2022 for a diagnosis of primary osteoarthritis. Patients were randomized into 2 groups: group 1 underwent a routine bursal repair, while group 2 did not, leaving the bursae unrepaired. Follow-up was performed on the 15th, 30th, and 90th day postoperatively with clinical scores, physical examinations, and laboratory tests. In this cohort of 104 patients, mean age was 55 years (range, 26 to 88). Demographic variables as well as range of motion and overall clinical results showed no significant difference between the groups. RESULTS: DGS rates were significantly more common in the patients who had an unrepaired bursa (group 2) both on the 30th and 90th postoperative days, while comparison of lateral trochanteric pain on palpation showed similar results between the groups. CONCLUSIONS: DGS is common in individuals who have unrepaired trochanteric bursal tissue following a THA. Despite its higher frequency, these symptoms did not have a substantial impact on the overall clinical scores, which remained consistent across the study groups.

A three-headed piriformis muscle: an anatomical case study and narrative review of literature.

The piriformis muscle (PM) is found in the gluteal region, exiting the pelvis through the greater sciatic foramen and dividing it into the suprapiriform and infrapiriform foramina. The piriformis works as part of the hip external rotator muscle group, and is responsible for rotation of the femur upon hip extension and abduction of the femur during flexion of the hip joint. The aim of the present report is to describe a very rare case of the primary three-headed PM. To the best knowledge of the authors, the said variant has not yet been described in the existing literature. The 71-year-old male formalin-fixed cadaver was subjected to routine dissection. After careful removal of the connecting tissue, three separate, primary heads of the PM were identified. The lower head of the PM arose from the middle part of the sacral bone; 87.56 mm long and 9.73 mm wide. The medial head was attached to the internal part of the posterior inferior iliac spine; 121.6 mm long and 20.97 mm wide. The upper head was attached to the external part of the posterior inferior iliac spine; 78.89 mm long and 23.94 mm wide. All heads converged into a common tendon which inserted onto the greater trochanter. The clinical importance of this work comes down to the fact that the aberrant PM may be the reason behind the piriformis syndrome and its associated symptoms. Moreover, knowledge regarding the variant anatomy of the PM is of immense importance to, e.g. anaesthesiologists performing computed tomography- or ultrasound-guided sciatic nerve injection for local anaesthesia, radiologists interpreting imaging studies, and surgeons, especially during posterior approaches to the hip and pelvis.

Does endoscopic piriformis tenotomy provide safe and complete tendon release? A cadaver study.

BACKGROUND: Endoscopic piriformis release (EPR) is among the available treatments for piriformis syndrome. This procedure typically involves dividing the muscle near the sciatic nerve in the sub-gluteal space, which contains numerous blood vessels and nerves. The objectives of this prospective cadaver study were: 1) to assess the reproducibility and quality of endoscopic piriformis tenotomy near the greater trochanter; 2) to detect iatrogenic injuries to the lateral hip rotators, nerves, and vessels; 3) and to define the surgical safety margins relative to the sciatic nerve and inferior gluteal bundle. HYPOTHESIS: EPR at the greater trochanter ensures full release of the muscle with a limited risk of neuro-vascular injury. MATERIAL AND METHODS: EPR was performed via two portals on 10 cadaver hips preserved in zinc chloride and placed in the prone position. A third, ancillary portal was required in 7 cases. The area was then dissected with the Kocher-Langenbeck approach to allow an assessment of the tenotomy, detect iatrogenic injuries, and measure the distances separating the tenotomy site from the sciatic nerve and inferior gluteal artery. RESULTS: Complete tenotomy was achieved in 9 (90%) cases. The tendon adhered to the capsule in 2 (20%) cases and showed acquired avulsion in 1 case. No injuries to the sciatic nerve or inferior gluteal artery occurred. Mean distances from the tenotomy site were 5.21±0.59cm (range, 4.5-6.6cm) for the sciatic nerve and 7.1±0.89cm (range, 5.4-8.5cm) for the inferior gluteal artery. DISCUSSION: EPR by a tenotomy at the greater trochanter without sciatic nerve release provides full release of the muscle with satisfactory safety margins and a short learning curve. LEVEL OF EVIDENCE: III, prospective cadaver case-control study.

Endoscopic treatment of sciatic nerve entrapment in deep gluteal syndrome: Clinical results. / Manejo endoscópico del atrapamiento del nervio ciático en el síndrome de glúteo profundo: resultados clínicos.

INTRODUCTION: Deep gluteal syndrome (DGS) is characterized by compression, at extra-pelvic level, of the sciatic nerve within any structure of the deep gluteal space. The objective was to evaluate the clinical results in patients with DGS treated with endoscopic technique. METHODS: Retrospective study of patients with DGS treated with an endoscopic technique between 2012 and 2016 with a minimum follow-up of 12 months. The patients were evaluated before the procedure and during the first year of follow-up with the WOMAC and VAIL scale. RESULTS: Forty-four operations on 41 patients (36 women and 5 men) were included with an average age of 48.4±14.5. The most common cause of nerve compression was fibrovascular bands. There were two cases of anatomic variant at the exit of the nerve; compression of the sciatic nerve was associated with the use of biopolymers in the gluteal region in an isolated case. The results showed an improvement of functionality and pain measured with the WOMAC scale with a mean of 63 to 26 points after the procedure (P<.05). However, at the end of the follow-up one patient continued to manifest residual pain of the posterior cutaneous femoral nerve. Four cases required revision at 6 months following the procedure due to compression of the scarred tissue surrounding the sciatic nerve. CONCLUSION: Endoscopic release of the sciatic nerve offers an alternative in the management of DGS by improving functionality and reducing pain levels in appropriately selected patients.

[Tendonitis calcarea of the piriformis muscle in a young amateur athlete]. / Tendinitis calcarea des M. piriformis bei einer jungen Amateursportlerin.

Distinct calcific tendonitis associated with chronic pain refractory to conservative treatment can require operative treatment. Symptomatic calcific tendonitis of the piriform muscle, despite calcific tendonitis of other regions, is an extremely rare diagnosis. We report about a young athlete with persistent gluteal pain despite long-term conservative treatment. MRI scans revealed tendonitis calcarea with surrounding soft tissue inflammation. On open surgical removal of the calcification, pain symptoms were relieved and the patient was able to return to sports.

Refractory sciatica caused by gluteal varicosities.

We report a case of sciatica that fulfilled the diagnostic criteria for inferior gluteal vein varicosities according to patient history and on magnetic resonance imaging. Since conservative treatment was ineffective, excision-ligation of the varicose vein was performed as recommended in the previous literature. However, pain was only slightly relieved and then aggravated. Reoperation involving wide release and resection of the piriformis outlet was performed. Pain resolved immediately thereafter. We suggest that this case of sciatica resulted from both piriformis entrapment and vein varicosities. The piriformis entrapment led to inferior gluteal vein backflow obstruction, and varicosities could have been the trigger of piriformis syndrome. Excision-ligation of the varicose vein and piriformis release were recommended.

Piriformis muscle syndrome with assessment of sciatic nerve using diffusion tensor imaging and tractography: a case report.

Piriformis muscle syndrome (PMS) is difficult to diagnose by objective evaluation of sciatic nerve injury. Here we report a case of PMS diagnosed by diffusion tensor imaging (DTI) and tractography of the sciatic nerve, which can assess and visualize the extent of nerve injury. The patient was a 53-year-old man with a 2-year history of continuous pain and numbness in the left leg. His symptoms worsened when sitting. Physical examination, including sensorimotor neurologic tests, the deep tendon reflex test, and the straight leg raise test, revealed no specific findings. The hip flexion adduction and internal rotation test and resisted contraction maneuvers for the piriformis muscle were positive. There were no abnormal findings on magnetic resonance imaging (MRI) of the lumbar spine. The transverse diameter of piriformis muscle was slightly thicker in affected side on MRI of the pelvis. A single DTI sequence was performed during MRI of the pelvis. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the sciatic nerve were quantified at three levels using the fiber-tracking method. FA values were significantly lower and ADC values were significantly higher distal to the piriformis muscle. We performed endoscopic-assisted resection of the piriformis tendon. Intraoperatively, the motor-evoked potentials in the left gastrocnemius were improved by resection of the piriformis tendon. The patient's symptoms improved immediately after surgery. There was no significant difference in FA or ADC at any level between the affected side and the unaffected side 3 months postoperatively. MRI-DTI may aid the diagnosis of PMS.

Surgical Treatment of Piriformis Syndrome.

BACKGROUND: Piriformis syndrome (PS) is an uncommon disease characterized by symptoms resulting from compression/irritation of the sciatic nerve by the piriformis muscle. Uncertainty and controversy remain regarding the proper diagnosis and most effective form of treatment for PS. This study analyzes the diagnostic methods and efficacy of conservative and surgical treatments for PS. METHODS: From March 2006 to February 2013, we retrospectively reviewed 239 patients who were diagnosed with PS and screened them for eligibility according to our inclusion/exclusion criteria. All patients underwent various conservative treatments initially including activity modification, medications, physical therapy, local steroid injections into the piriformis muscle, and extracorporeal shock wave therapy for at least 3 months. We resected the piriformis muscle with/without neurolysis of the sciatic nerve in 12 patients who had intractable sciatica despite conservative treatment at least for 3 months. The average age of the patients (4 males and 8 females) was 61 years (range, 45 to 71 years). The average duration of symptoms before surgery was 22.1 months (range, 4 to 72 months), and the mean follow-up period was 22.7 months (range, 12 to 43 months). We evaluated the degree of pain and recorded the responses using a visual analog scale (VAS) preoperatively and 3 days and 12 months postoperatively. RESULTS: Buttock pain was more improved than sciatica with various conservative treatments. Compared with preoperatively, the VAS score was significantly decreased after the operation. Overall, satisfactory results were obtained in 10 patients (83%) after surgery. CONCLUSIONS: PS is thought to be an exclusively clinical diagnosis, and if the diagnosis is performed correctly, surgery can be a good treatment option in patients with refractory sciatica despite appropriate conservative treatments.

Clinical results of endoscopic sciatic nerve decompression for deep gluteal syndrome: mean 2-year follow-up.

BACKGROUND: The purpose of this study is to assess the effectiveness of endoscopic sciatic nerve decompression and evaluated the differences of clinical results between atraumatic and traumatic groups. METHODS: Sixty consecutive patients. We retrospectively reviewed sixty consecutive patients without major trauma (45 hips) or with major trauma (15 hips) groups to compare the outcomes of endoscopic treatment.). The mean follow-up period was 24 ± 2.6 months (range, 24-38.4 months). RESULTS: The mean duration of symptoms was 14.1 months (range, 12 to 32 months). Compromising structures were piriformis muscle, fibrovascular bundles, and adhesion with scar tissues. The mean VAS score for pain decreased from 7.4 ± 1.5 to 2.6 ± 1.5 (P = .001). The mean mHHS increased from 81.7 ± 9.6 to 91.8 ± 7.6 (P = .003). Clinically, positive paresthesia and seated piriformis test were statistically significant to diagnosis sciatic entrapment syndrome. Paresthesia and sitting pain were significantly improved at the final follow-up (P = .002). More favorable outcome was observed a group without major trauma. No complication was observed. CONCLUSIONS: Endoscopic sciatic nerve decompression is a safe and effective procedure for the management of DGS. Patients with major trauma could have poor clinical outcome. Seated piriformis test, FADIR, and tenderness of sciatic notch are maybe useful guide for pre and postoperative evaluation of DGS.

Piriformis Syndrome and Endoscopic Sciatic Neurolysis.

Piriformis syndrome is the compression or the irritation of the sciatic nerve by the adjacent piriformis muscle in the buttock leading to symptoms that include buttock pain, leg pain, and altered neurology in the sciatic nerve distribution. Epidemiological figures of the prevalence are unknown, but are estimated to be about 12.2% to 27%. There is no consensus on the diagnostic criteria. Advancement in magnetic resonance imaging allows us to observe unilateral hyperintensity and bowing of the sciatic nerve. The pathophysiology of the disease includes single blunt trauma, overuse causing piriformis hypertrophy, and long-term microtrauma causing scarring. Treatments include physiotherapy, steroid injections, and surgery. Minimally invasive techniques are emerging with the hope that with less postoperative scar tissue formation, there will be less recurrence of the disease. In this chapter, senior author describes his technique for endoscopic sciatic neurolysis.

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).

Piriformis syndrome--a rare cause of extraspinal sciatica.

Piriformis syndrome is a rare entity resulting in severe unilateral isolated buttock pain shooting in nature, non discogenic in origin. MR imaging of pelvis plays an important role in such patients to see the normal anatomy of piriformis muscle and its relationship with sciatic nerve. A 35-year-old woman presented with one year history of radiating leg pain with normal MR lumbosacral spine. MRI pelvis showed an abnormal orientation of left sciatic nerve through cleaved fibers of the piriformis muscle. The patient's symptoms were relieved by surgical decompression. The purpose of this case report is to show the role and importance of MR imaging for tracing sciatic nerve and its relationship to the Piriformis muscle. MR imaging of pelvis for sciatic nerve plays an important role in symptomatic patients with isolated buttock pain having normal MRI lumbosacral spine.

[Pyrimidal syndrome and anatomical variations as a cause of insidious sciatic pain]. / Síndrome piramidal y variaciones anatómicas como causa de dolor ciático insidioso.

The case is presented of a 42 year old woman who had been suffering a loss of strength in her left leg for six years. After an extensive diagnostic study, the pain was classified as of functional origin by a diagnosis of exclusion. Since then, the patient has tried all kind of drug treatments and conservative techniques without improvement. After an exhaustive study with inconclusive results, the case was discussed with the Orthopaedics Department, who performed an exploratory surgery, in which compression of the sciatic nerve due to an anatomical variation of the piriformis muscle was observed. Part of the muscle was resected during surgery and the sciatic nerve was freed, after which the patient experienced a great improvement.

Anatomical variations between the sciatic nerve and the piriformis muscle: a contribution to surgical anatomy in piriformis syndrome.

PURPOSE: To detect the variable relationship between sciatic nerve and piriformis muscle and make surgeons aware of certain anatomical features of each variation that may be useful for the surgical treatment of the piriformis syndrome. METHODS: The gluteal region of 147 Caucasian cadavers (294 limbs) was dissected. The anatomical relationship between the sciatic nerve and the piriformis muscle was recorded and classified according to the Beaton and Anson classification. The literature was reviewed to summarize the incidence of each variation. RESULTS: The sciatic nerve and piriformis muscle relationship followed the typical anatomical pattern in 275 limbs (93.6 %). In 12 limbs (4.1 %) the common peroneal nerve passed through and the tibial nerve below a double piriformis. In one limb (0.3 %) the common peroneal nerve coursed superior and the tibial nerve below the piriformis. In one limb (0.3 %) both nerves penetrated the piriformis. In one limb (0.3 %) both nerves passed above the piriformis. Four limbs (1.4 %) presented non-classified anatomical variations. When a double piriformis muscle was present, two different arrangements of the two heads were observed. CONCLUSIONS: Anatomical variations of the sciatic nerve around the piriformis muscle were present in 6.4 % of the limbs examined. When dissection of the entire piriformis is necessary for adequate sciatic nerve decompression, the surgeon should explore for the possible existence of a second tendon, which may be found either inferior or deep to the first one. Some rare, unclassified variations of the sciatic nerve should be expected during surgical intervention of the region.

Piriformis muscle syndrome: diagnostic criteria and treatment of a monocentric series of 250 patients.

OBJECTIVES: Piriformis Muscle Syndrome (PMS) is caused by sciatic nerve compression in the infrapiriformis canal. However, the pathology is poorly understood and difficult to diagnose. This study aimed to devise a clinical assessment score for PMS diagnosis and to develop a treatment strategy. MATERIAL AND METHODS: Two hundred and fifty patients versus 30 control patients with disco-radicular conflict, plus 30 healthy control subjects were enrolled. A range of tests was used to produce a diagnostic score for PMS and an optimum treatment strategy was proposed. RESULTS: A 12-point clinical scoring system was devised and a diagnosis of PMS was considered 'probable' when greater or equal to 8. Sensitivity and specificity of the score were 96.4% and 100%, respectively, while the positive predictive value was 100% and negative predictive value was 86.9%. Combined medication and rehabilitation treatments had a cure rate of 51.2%. Hundred and twenty-two patients (48.8%) were unresponsive to treatment and received OnabotulinumtoxinA. Visual Analogue Scale (VAS) results were 'Very good/Good' in 77%, 'Average' in 7.4% and 'Poor' in 15.6%. Fifteen of 19 patients unresponsive to treatment underwent surgery with 'Very good/Good' results in 12 cases. CONCLUSIONS: The proposed evaluation score may facilitate PMS diagnosis and treatment standardisation. Rehabilitation has a major role associated in half of the cases with botulinum toxin injections.

Piriformis syndrome surgery causing severe sciatic nerve injury.

Piriformis syndrome is a controversial entrapment neuropathy in which the sciatic nerve is thought to be compressed by the piriformis muscle. Two patients developed severe left sciatic neuropathy after piriformis muscle release. One had a total sciatic nerve lesion, whereas the second had a predominantly high common peroneal nerve lesion. Follow-up studies showed reinnervation of the hamstrings only. We conclude that piriformis muscle surgery may be hazardous and result in devastating sciatic nerve injury.

Piriformis syndrome versus radiculopathy following lumbar artificial disc replacement.

STUDY DESIGN: Case series. OBJECTIVE: To describe the presentation, diagnostic challenges, and treatment of five patients with piriformis syndrome after lumbar artificial disc replacement. SUMMARY OF BACKGROUND DATA: Until recently, spinal fusion was considered the standard for surgical treatment of severe lumbar degenerative disc disease. However, artificial disc replacement now offers an alternative solution. Piriformis syndrome results from entrapment of the sciatic nerve at the greater sciatic notch, with symptoms of pain and numbness radiating from the buttock to the foot, mimicking radiculopathy. METHODS: In this case series, we report five patients who developed piriformis at our institution after artificial disc replacement. RESULTS: Five patients, aged 35 to 46 years, developed some or all of the following symptoms in the affected leg after artificial disc replacement: posterior leg and buttock pain, calf weakness, and toe and ball of foot numbness and tingling. The onset of symptoms ranged from 6 days to 8 months postoperative, and became debilitating over time. Each patient was diagnosed with piriformis syndrome through physical examination. Three of the patients received a piriformis injection and reported 50% to 100% pain relief lasting 1 to 3 weeks. The patients subsequently underwent physical therapy that provided relief of their piriformis syndrome-related pain and enabled them to resume their normal activities. CONCLUSION: Piriformis syndrome has not previously been described in the literature as a sequela of lumbar artificial disc replacement. Our case series indicates that this complication may be underdiagnosed. Careful consideration after artificial disc replacement is required if the patient presents with buttock, leg or foot pain, and/or numbness. It is important for physicians to recognize the symptoms of piriformis syndrome and to differentiate piriformis syndrome from nerve root compression and irritation or referred pain from spinal structures. Although controversial, the proper diagnosis of piriformis syndrome may have prevented some of these patients from undergoing unnecessary surgical procedures.

Arthroscopic treatment of piriformis syndrome by perineural cyst on the sciatic nerve: a case report.

This is a case report of an arthroscopic treatment performed on a patient with piriformis syndrome due to perineural cyst on piriformis muscle and sciatic nerve. Confirmation, incision, and drainage of benign cystic lesion on the sciatic nerve below the piriformis muscle were performed following the release of the piriformis tendon through the posterior and posteroinferior arthroscopic portal. Recurrence of the symptoms has not been observed since postoperative period of 20 months. Nor did the MRI taken after the procedure reveal any such recurrence.

Surgical release of the internal obturator tendon for the treatment of retro-trochanteric pain syndrome: a prospective randomized study, with long-term follow-up.

Twelve patients with clinical signs of retro-trochanteric pain syndrome were randomized to either operative treatment or a control group. Six patients were operated on with sectioning of the tendon to the internal obturator near its insertion to the trochanter major. There was no significant pain decrease in either group at 6 months. However, at 8 years, the decrease in pain was significant in the surgical group (P < 0.03) but not in the control group. Three patients in the surgical group who needed pain medication with opioids preoperatively managed without such drugs at 8 years. Two patients in the surgical group were working half time at the 8 year follow-up. Before the start of the study the patients had been out of work for 3 and 10 years, respectively. At inclusion 4/12 patients had minor degenerative changes at the L3-L5 level as seen on computerized tomography or magnetic resonance imaging. At 8 years, the corresponding change was found in 7/9 patients (P = 0.025). In conclusion, at 8 years after surgical release of the internal obturator muscle, the patients had a significant decrease in pain compared with the finding at inclusion. The corresponding was not found in the control group.