Piriformis Injection Research Articles

Gluteal Muscle Weakness and Piriformis Syndrome Relationship

In this short review, we aim to provide the relationship between gluteal muscle weakness and piriformis syndrome, an underdiagnosed cause of buttock and leg pain that mimics pyriformis syndrome can be of gluteal muscle weakness origin. This can be difficult to treat. Based on existing evidence, the present study discussed the available literature on the relation between pyriformis syndrome and its treatment as gluteal muscle strengthening. Source was literature search of the MEDLINE, Scopus and PubMed database from recent years using the search terms e.g., ‘‘piriformis injection’, ‘‘gluteal muscle’ and ‘‘gluteal muscle weakness. There was no restriction on language. Different structures relevant in this review suggested that there is negative impression of gluteal muscle strength on pyriformis syndrome and adopting gluteal muscle strengthening program in pyriformis syndrome will reduce pain and discomfort in patients in pyriformis syndrome symptoms.

TARGETED ULTRASOUND-GUIDED PERINEURAL HYDRODISSECTION OF THE SCIATIC NERVE AND CORTICOSTEROID INJECTION FOR THE TREATMENT OFPIRIFORMIS SYNDROME

Piriformis syndrome is a common cause of lumbar, gluteal, and thigh pain frequently associated with sciatic nerve symptoms. Etiology depends on individual predisposition or congenital anomalies. The mechanism is sciatic nerve impingement under the tendinous portion of the piriformis muscle due to spasm of the muscle. There is a common pathological end pathway involving hypertrophy, spasm, contracture, inammation, and scarring of the piriformis muscle, leading to impingement of the sciatic nerve. Ultrasound guided piriformis injection is frequently used in the treatment of piriformis syndrome, with most of the published literature describing injection of the muscle. We described a safe, effective ultrasound-guided injection technique for the treatment of piriformis syndrome among patients attending Physical Medicine & Rehabilitation (PMR) outpatient and inpatient departments in SSKM hospital, Kolkata (December 2019-June 2021) not responding to conservative management by using the targeted sciatic perineural hydrodissection followed by therapeutic corticosteroid injection.

The effectiveness of piriformis injection under fluoroscopy and nerve stimulator guidance with local anaesthetic and steroid for management of piriformis syndrome among manual workers in Eastern India: A prospective interventional study

Background: Piriformis syndrome (PS) is a neuromuscular disorder characterized by compression or irritation of sciatic nerve by the piriformis muscle causing pain, tingling, and numbness in the buttocks and sometimes along the distribution of the sciatic nerve descending down to the leg. Pharmacotherapy and physical-therapy remain the first line of management. Local anesthetic (LA) with steroid injection in piriformis muscle is given if conservative management fails. Nerve stimulator, electromyography, radiological imaging, and various other methods have been used to increase the reliability of injections. In the present study, the efficacy of combined fluoroscopy and nerve stimulator guided piriformis injection with LA and steroid for the management of PS has been re-validated among the manual workers of Eastern India. Subjects and Methods: With ethical permission and informed consent from 35 patients of PS fulfilling the inclusion and exclusion criteria were given piriformis injection with 5 mL of 0.25% bupivacaine and 20 mg methyl prednisolone under guidance of a combination of fluoroscopy and nerve stimulator. Thirty-one patients completed the study. Pain in Numeric Rating Scale and Disability by Ronald Morris Disability Questionnaire were recorded for all patients before the procedure, 1 h, 1 week, 3 weeks, and 12 weeks after the procedure and were statistically analyzed. Results: Pain score and back disability score decreased significantly (P < 0.05) after the injection, and the effect was also sustained up to 12 weeks. Conclusions: Injection of LA along with steroid in piriformis muscle under fluoroscopy and nerve stimulator guidance, followed by physiotherapy, is an effective treatment for PS among manual workers.

Targeted Ultrasound-Guided Perineural Hydrodissection of the Sciatic Nerve for the Treatment of Piriformis Syndrome.

Piriformis syndrome is a common cause of lumbar, gluteal, and thigh pain, frequently associated with sciatic nerve symptoms. Potential etiologies include muscle injury or chronic muscle stretching associated with gait disturbances. There is a common pathological end pathway involving hypertrophy, spasm, contracture, inflammation, and scarring of the piriformis muscle, leading to impingement of the sciatic nerve. Ultrasound-guided piriformis injections are frequently used in the treatment of these pain syndromes, with most of the published literature describing injection of the muscle. We describe a safe, effective ultrasound-guided injection technique for the treatment of piriformis syndrome using targeted sciatic perineural hydrodissection followed by therapeutic corticosteroid injection.

Sacroiliac joint denervation, the joint and ligaments: aretrospective study and algorithm

Introduction We included patients who had sacroiliac joint complex pain (SIJCP) and failing all conservative approaches to alleviate SIJCP, all had SI joint procedure with fluoroscopic guidance. Some had more than 3 months of better than 50% with SI steroid injection (62/144 patients), others became candidates for sacroiliac joint complex sensory radiofrequency (RF) denervation for long-term pain relief (24 patients), with facet denervation (22 patients) or with piriformis injection (19 patients). Materials and methods In all, 170 patient charts were reviewed, and 17 were excluded for unclear block results and 26 for discogenic pathology. Fluoroscopy and 10 or 15-mm active tip RF cannula was used. An imaginary stripline was drawn about 3–5 cm medial and parallel to the joint line. Posterior primary sensory denervation was then carried out through 10–15 mm segments in series. Denervation was repeated 9–12 months later if greater than 50% of original pain had returned (first repeat and second repeat). The denervation process was then expanded to other sets of patients having (II) SIJCP plus ipsilateral lumbar facet pain and (III) SIJCP plus ipsilateral piriformis syndrome exclusively. Results All groups showed an increase in activities of daily living (through Oswestry Scores), better pain score, and at least 45 weeks improvement of pain score after RF denervation. Conclusion SIJCP can be effectively (50% or better) reduced for 4.5 months with steroid injection, or 10–12 months with denervation. The procedures were repeated once or twice with the same effectiveness. The method of pain management through our approach is effective, safe, simple, and reproducible.

Prolonged Weakness After Piriformis Injection: A Case Report

Prolonged Weakness After Piriformis Injection: A Case Report

A case of piriformis syndrome presenting as radiculopathy

Piriformis syndrome has always remained as a diagnostic dilemma because of its varied presentation. Piriformis syndrome is myofascial dysfunction syndrome which causes pain not only because of trigger points within the muscle but also due to peripheral neuritis of the sciatic nerve. The sciatic neuritis is due to compression of the nerve as it passes through the greater sciatic foramen. The symptoms of sciatic nerve entrapment caused by the piriformis syndrome can be easily mistaken for radiculopathy as the nerve entrapment causes pain which radiates down below the knee and can go up to the foot. Electromyography (EMG) and nerve conduction velocity (NCV) studies can help differentiating these two conditions and can eliminate the need for the magnetic resonance imaging (MRI). In this paper, we have reported a case of piriformis syndrome which mimicked S 1 radiculopathy, where diagnosis was confirmed by diagnostic piriformis injection.

A Randomized Comparison of the Efficacy of 2 Techniques for Piriformis Muscle Injection

Piriformis muscle injections are most often performed using fluoroscopic guidance; however, ultrasound (US) guidance has recently been described extensively in the literature. No direct comparisons between the 2 techniques have been performed. Our objective was to compare the efficacy and efficiency of fluoroscopic- and US-guided techniques. A randomized, comparative trial was carried out to compare the 2 techniques. Twenty-eight patients with a diagnosis of piriformis syndrome, based on history and physical examination, who had failed conservative treatment were enrolled in the study. Patients were randomized to receive the injection either via US or fluoroscopy. Injections consisted of 10 mL of 1% lidocaine with 80 mg of triamcinalone. The primary outcome measure was numeric pain score, and secondary outcome measures included functional status as measured by the Multidimensional Pain Inventory, patient satisfaction as measured by the Patient Global Impression of Change scale, and procedure timing characteristics. Outcome data were measured preprocedure, immediately postprocedure, and 1 to 2 weeks and 3 months postprocedure. We found no statistically significant differences in numeric pain scores, patient satisfaction, procedure timing characteristics, or most functional outcomes when comparing the 2 techniques. Statistically significant differences between the 2 techniques were found with respect to the outcome measures of household chores and outdoor work. Ultrasound-guided piriformis injections provide similar outcomes to fluoroscopically guided injections without differences in imaging, needling, or overall procedural times.

Brief review: Piriformis syndrome: etiology, diagnosis, and management

In this narrative review, we aim to provide the pathophysiology and diagnostic criteria of the piriformis syndrome (PS), an underdiagnosed cause of buttock and leg pain that can be difficult to treat. Based on existing evidence, frequencies of clinical features are estimated in patients reported to have PS. In view of the increasing popularity of ultrasound for intervention, the ultrasound-guided technique in the treatment of PS is described in detail. A literature search of the MEDLINE® database was performed from January 1980 to December 2012 using the search terms e.g., " piriformis injection", " ultrasound guided piriformis injection", " botulinum toxin", "pain management", and different structures relevant in this review. There was no restriction on language. A review of the medical literature pertaining to PS revealed that the existence of this entity remains controversial. There is no definitive proof of its existence despite reported series with large numbers of patients. Piriformis syndrome continues to be a controversial diagnosis for sciatic pain. Electrophysiological testing and nerve blocks play important roles when the diagnosis is uncertain. Injection of local anesthetics, steroids, and botulinum toxin into the piriformis muscle can serve both diagnostic and therapeutic purposes. An ultrasound-guided injection technique offers improved accuracy in locating the piriformis muscle. Optimizing the therapeutic approach requires an interdisciplinary evaluation of treatment.

Needle Placement for Piriformis Injection Using 3-D Imaging

Piriformis syndrome is a pain syndrome originating in the buttock and is attributed to 6% – 8% of patients referred for the treatment of back and leg pain. The treatment for piriformis syndrome using fluoroscopy, computed tomography (CT), electromyography (EMG), and ultrasound (US) has become standard practice. The treatment of Piriformis Syndrome has evolved to include fluoroscopy and EMG with CT guidance. We present a case study of 5 successful piriformis injections using 3-D computer-assisted electromagnet needle tracking coupled with ultrasound. A 6-degree of freedom electromagnetic position tracker was attached to the ultrasound probe that allowed the system to detect the position and orientation of the probe in the magnetic field. The tracked ultrasound probe was used to find the posterior superior iliac spine. Subsequently, 3 points were captured to register the ultrasound image with the CT or magnetic resonance image scan. Moreover, after the registration was obtained, the navigation system visualized the tracked needle relative to the CT scan in real-time using 2 orthogonal multi-planar reconstructions centered at the tracked needle tip. Conversely, a recent study revealed that fluoroscopically guided injections had 30% accuracy compared to ultrasound guided injections, which tripled the accuracy percentage. This novel technique exhibited an accurate needle guidance injection precision of 98% while advancing to the piriformis muscle and avoiding the sciatic nerve. The mean (± SD) procedure time was 19.08 (± 4.9) minutes. This technique allows for electromagnetic instrument tip tracking with realtime 3-D guidance to the selected target. As with any new technique, a learning curve is expected; however, this technique could offer an alternative, minimizing radiation exposure. Key words: Piriformis, electromagnetic, ultrasound, fluoroscopy, injection, 3-D imaging.

Prevalence of piriformis syndrome among the cases of low back/buttock pain with sciatica: A prospective study

Aim: The aim of this study was to find out the prevalence and causes of piriformis syndrome in patients with complain of low back pain/buttock pain with sciatica attending Regional Institute of Medical Sciences (RIMS), Imphal. Materials and Methods: All the patients in the study group attending Orthopedic and Physical Medicine and Rehabilitation Out-patient Department in RIMS, Imphal were examined. Those with increased symptoms on sitting, localized significant tenderness on palpation of the muscle, presence of one or more of the following tests: Freiberg, pace, beatty, and FAIR (Flexion , Adduction and Internal Rotation) maneuvers with negative X-ray, ultrasound, computed tomography and magnetic resonance imaging findings were subjected to piriformis muscle injection of lidocaine (2%) 2 ml and methyl prednisolone 2 ml (40 mg) for confirmation of diagnosis. Result: Out of 2910 patients, 182 cases (M: 28, F: 154) in the age range of 19-75 years with a mean age of 43 years were clinically diagnosed as piriformis syndrome. Prevalence of piriformis syndrome was 6.25%. Conclusion: Piriformis syndrome is one of the differential diagnoses of low back/buttock pain with Sciatica. Individuals of all activity levels can be affected. Females are more affected than males. Causes are overuse, prolonged sitting, trauma, and vigorous massage. Diagnosis is by exclusion of other causes. Simple injection with local anesthetic and steroid in the piriformis muscle is both therapeutic and confirmatory of diagnosis. Early diagnosis and treatment with injection of piriformis muscle can prevent further complications and risks of surgery, which is also not 100% curative. With proper care, piriformis injection can be carried out without any complication. Long-term study is needed to evaluate the recurrence after injection treatment.

Leg length discrepancy as a rare cause of a piriformis syndrome

Dere et al. [3] presented two female patients with piriformis syndrome (PS) who had a shorter leg on the effected side. Triamcinolone piriformis injections with equalization of patients’ leg lengths using insoles solved the problems without further recurrence of PS symptoms. The authors concluded that a “short leg” is one of the rarer causes of PS and it can be seen alone or in combination with other causal factors. There was no mention of any articles which presented the issue of leg length discrepancy related to PS in the English medical literature [1,2,4–7,9], and there was no biomechanical explanation of the causal factor. Therefore, we would like to emphasize a few facts pertaining to this issue. To the best of our knowledge, TePoorten [9] was the first to mention shortness of the affected extremity among signs of PS 40 years prior to the publication of Dere et al. [3]. Several years later, Retzlaff et al. [7] emphasized that the leg on the affected side is shortened due to a contracture of the piriformis muscle. In cases where the leg on the opposite side appears shortened, it is probable that some other dysfunction exists and that the condition is not directly related to the PS. On the other hand, Hallin [5] stated that pain and tenderness are most often on the “long side”, but may be bilateral or on the short side only. It should be mentioned that a 1 cm elongation of the affected leg was identified as a

Ultrasound Guided Piriformis Injection with Confirmation of Needle Placement Through Electromyography

Dear Editor: Piriformis syndrome is a controversial topic that consists of a constellation of symptoms that may mimic spondylosis, radiculopathy, sacroiliac joint pain, and facet arthropathy [1]. One of the modalities of piriformis syndrome treatment is direct injection of medication into the piriformis muscle belly [2]. Previous authors have reported various methods in performing piriformis injections: fluoroscopically, motor stimulation, and most recently, ultrasound (US) guidance [3–5]. We describe a case presentation and, to our knowledge, the first report of combined use of US with electromyography (EMG) confirmation of muscle placement for piriformis muscle injection. A 60-year-old male presented to our clinic with lower back, left hip, and left buttock pain for 6 years. The pain was sharp in quality and radiated toward the left lateral buttock and hip. The pain was rated 6/10 at initial presentation and was aggravated by prolonged sitting, squatting, and bending over. Pain was improved with rest. On examination, the patient demonstrated mild tenderness along the left lumbar spine and paraspinal muscles, as well as tenderness to palpation in the left lateral buttock area. Straight leg raise test was positive in the left lower extremity. Motor examination revealed full …

Ultrasound guided piriformis injection with confirmation of needle placement through electromyography: a case report and description of a new technique

A 60 year old male presented to our clinic with lower back, left hip and left buttocks pain for 6 years. The pain was sharp in quality, and radiated toward the left lateral buttock and hip. The pain was rated 6/10, and aggravated by prolonged sitting, squatting, and bending over. On examination, the patient demonstrated tenderness along left lumbar paraspinals and lateral buttocks area. Straight leg raise and FAIR test was positive in LLE. Prior electromyography exam demonstrated a left L5 motor radiculopathy. L-spine MRI revealed multilevel degenerative disc disease. Having previously failed conservative treatment, including PT and gabapentin, a caudal epidural was performed. The patient reported no improvement in his symptoms after the injection. Upon further assessment, diagnosis of piriformis syndrome was considered. A diagnostic injection of lidocaine was performed under ultrasound and EMG guidance into the piriformis muscle. After the injection, the patient had relief of pain. One of the main treatments of piriformis syndrome is injection of local anesthetic or steroids into the piriformis muscle belly. Due to difficulty with needle placement, previous authors have reported various methods in performing piriformis injections: fluoroscopically, motor stimulation, and most recently, ultrasound guidance. With ultrasound alone, even with visualization of needle placement, it is difficult to ensure needle insertion into the piriformis muscle, as opposed to surrounding muscles, specifically the gluteus medius and gluteus maximus. To our knowledge, this is the first report of combined use of ultrasound with EMG confirmation of needle placement for a piriformis injection. Our technique offers the advantage of decreased radiation exposure when compared to fluoroscopy and verification of needle placement into the piriformis when compared to injections without EMG. In addition, our case presentation emphasizes the ability for piriformis syndrome to mimic other diagnosis. A 60 year old male presented to our clinic with lower back, left hip and left buttocks pain for 6 years. The pain was sharp in quality, and radiated toward the left lateral buttock and hip. The pain was rated 6/10, and aggravated by prolonged sitting, squatting, and bending over. On examination, the patient demonstrated tenderness along left lumbar paraspinals and lateral buttocks area. Straight leg raise and FAIR test was positive in LLE. Prior electromyography exam demonstrated a left L5 motor radiculopathy. L-spine MRI revealed multilevel degenerative disc disease. Having previously failed conservative treatment, including PT and gabapentin, a caudal epidural was performed. The patient reported no improvement in his symptoms after the injection. Upon further assessment, diagnosis of piriformis syndrome was considered. A diagnostic injection of lidocaine was performed under ultrasound and EMG guidance into the piriformis muscle. After the injection, the patient had relief of pain. One of the main treatments of piriformis syndrome is injection of local anesthetic or steroids into the piriformis muscle belly. Due to difficulty with needle placement, previous authors have reported various methods in performing piriformis injections: fluoroscopically, motor stimulation, and most recently, ultrasound guidance. With ultrasound alone, even with visualization of needle placement, it is difficult to ensure needle insertion into the piriformis muscle, as opposed to surrounding muscles, specifically the gluteus medius and gluteus maximus. To our knowledge, this is the first report of combined use of ultrasound with EMG confirmation of needle placement for a piriformis injection. Our technique offers the advantage of decreased radiation exposure when compared to fluoroscopy and verification of needle placement into the piriformis when compared to injections without EMG. In addition, our case presentation emphasizes the ability for piriformis syndrome to mimic other diagnosis.

Piriformis Muscle: Clinical Anatomy with Computed Tomography in Korean Population

BackgroundThe objective was to evaluate the distance from the skin and the diameter of the piriformis muscle and their relationship to the body mass index (BMI).MethodsThe study was a prospective study involving 60 patients. Patients were prepared on a radiological table in the prone position. Several images were obtained of each. In this view, the distance between the subcutaneous tissue and the piriformis muscle, and the diameter of the piriformis, were measured at three points (medially to laterally).ResultsThe distance to the piriformis from the skin was 6.6 ± 0.9 cm, 6.3 ± 0.8 cm, and 5.2 ± 0.9 cm in terms of the lateral, center, and medial measurement, respectively. The center of the piriformis had a greater diameter with 1.7 ± 0.4 (0.9-2.5) cm. The distance to the piriformis increased with BMI.ConclusionsThis study shows that the lateral of the piriformis muscle has a relatively greater distance from the skin. The center of the piriformis showed a greater diameter than other two portions. We found that the distance of the piriformis from subcutaneous tissues was correlated with BMI, but the diameter of the piriformis was not affected by BMI. These measurements can be used as a reference for determining the piriformis injection site in patients with piriformis syndrome.

Piriformis Syndrome Versus Radiculopathy Following Lumbar Artificial Disc Replacement

Case series. To describe the presentation, diagnostic challenges, and treatment of five patients with piriformis syndrome after lumbar artificial disc replacement. 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. In this case series, we report five patients who developed piriformis at our institution after artificial disc replacement. 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. 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.

Successful Treatment of Refractory Pudendal Neuralgia with Pulsed Radiofrequency

Pudendal neuralgia (PN) involves severe, sharp pain along the course of the pudendal nerve, often aggravated with sitting. Current therapies include medication management, nerve blocks, decompression surgery, and neuromodulation. The ideal management for PN has not been determined. We present a case of a female with 1.5 years of sharp, burning pain of the left gluteal and perineal regions. She could not sit for longer than 10 to 15 minutes. Sacroiliac joint, epidural, and piriformis injections did not improve her pain. She had tried physical therapy, occupational therapy, massage, and acupuncture but the pain persisted. Medication treatment with oxycodone-acetaminophen, extended release morphine sulfate, amitriptyline, and gabapentin provided only minor relief and she had failed other multianalgesic therapy. She had been unable to work at her desk job for over a year. She had a positive response to 2 diagnostic pudendal nerve blocks with lidocaine that provided pain relief for several hours. This patient elected to undergo pulsed radiofrequency (PRF) of the left pudendal nerve in hopes of achieving a longer duration and improved pain relief. PRF was carried out at a frequency of 2 Hz and a pulse width of 20 milliseconds for a duration of 120 seconds at 42 degrees Celsius. After the procedure she reported tolerating sitting for 4 to 5 hours. Her multianalgesic therapy was successfully weaned. At 5 months follow-up she felt motivated to return to work. One and a half years after the procedure the patient is only taking oxycodone-acetaminophen for pain relief and still has good sitting tolerance. There were no procedure-related complications. To our knowledge PRF for the treatment of PN has not been reported elsewhere in the literature. PRF is a relatively new procedure and is felt to be safer than continuous radiofrequency. Current literature suggests that PRF delivers an electromagnetic field, which modifies neuro-cellular function with minimal cellular destruction. We conclude that PRF of the pudendal nerve offers promise as a potential treatment of PN that is refractory to conservative therapy. Key words: pudendal neuralgia, pulsed radiofrequency, pudendal nerve, neuromodulation

The Effectiveness of Clonidine-Bupivacaine Repeated Nerve Stimulator-guided Injection in Piriformis Syndrome

Piriformis syndrome (PS) is often refractory to conventional therapies. Guided injection techniques generally necessitate a computed tomography or fluoroscopic guidance that may not be available in most pain management centers in addition to its relative high cost. The aim of this clinical trial is to investigate whether clonidine-bupivacaine nerve-stimulator guided injections are effective in achieving long-lasting pain relief in PS compared with bupivacaine guided injection. A pilot study conducted on 18 patients (15 females, 3 males) diagnosed with PS showed the adequacy of nerve stimulator guided technique assessed via confirmatory visualized tomography scan demonstrating a worthy coverage of the piriformis muscle in about 84% of the cases. This randomized double-blind trial included 80 patients with PS who received a nerve stimulator-guided piriformis injection (group C received 9 mL bupivacaine 0.5% and 1 mL clonidine 150 mcg/mL; group B received 9 mL bupivacaine 0.5% and 1 mL saline). Pain characteristics and analgesics consumption were the primary end points assessed for 6 months. Group C showed significantly lower pain scores and analgesics consumption than group B (P<0.0001). Pain at 6 months was significantly greater in group B (78%) than in group C (8%) (P<0.01). For every 18 months of PS pain, the outcomes demonstrated that a patient needed 1 additional injection to the initial injection. Repeated clonidine-guided piriformis injection relieved PS symptoms and reduce analgesic consumption for a 6-month period. It is a cost-effective useful treatment for PS refractory to traditional therapeutic approaches.

Accuracy of Ultrasound-Guided Versus Fluoroscopically Guided Contrast-Controlled Piriformis Injections

The purpose of this study was to compare the accuracy of ultrasound-guided piriformis injections with fluoroscopically guided contrast-controlled piriformis injections in a cadaveric model. Twenty piriformis muscles in 10 unembalmed cadavers were injected with liquid latex using both fluoroscopically guided contrast-controlled and US-guided injection techniques. All injections were performed by the same experienced individual. Two different colors of liquid latex were used to differentiate injection placement for each procedure, and the injection order was randomized. The gluteal regions were subsequently dissected by an individual blinded to the injection technique. Colored latex seen within the piriformis muscle, sheath, or both was considered an accurate injection. Nineteen of 20 ultrasound-guided injections (95%) correctly placed the liquid latex within the piriformis muscle, whereas only 6 of the 20 fluoroscopically guided contrast-controlled injections (30%) were accurate (P = .001). The liquid latex in 13 of the 14 missed fluoroscopically guided contrast-controlled piriformis injections and the single missed ultrasound-guided injection was found within the gluteus maximus muscle. In the single remaining missed fluoroscopically guided contrast-controlled piriformis injection, the liquid latex was found within the sciatic nerve. In this cadaveric model, ultrasound-guided piriformis injections were significantly more accurate than fluoroscopically guided contrast-controlled injections. Despite the use of bony landmarks and contrast, most of the fluoroscopically attempted piriformis injections were placed superficially within the gluteus maximus. Clinicians performing piriformis injections should be aware of the potential pitfalls of fluoroscopically guided contrast-controlled piriformis injections and consider using ultrasound guidance to ensure correct needle placement.

Confirmation of Needle Placement Within the Piriformis Muscle of a Cadaveric Specimen Using Anatomic Landmarks and Fluoroscopic Guidance

Of patients presenting to pain clinics, complaints are of low back or buttock pain with or without radicular leg symptoms is one of the most common. Piriformis syndrome may be a contributor in up to 8% of these patients. The mainstay of treatment is conservative management with physical therapy, anti-inflammatory medications, muscle relaxants, and correction of biomechanical abnormalities. However, in recalcitrant cases, a piriformis injection of anesthetic and/or corticosteroids may be considered. Because of its small size, proximity to neurovascular structures, and deep location, the piriformis muscle is often injected with the use of commuted tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), fluoroscopy, electrical stimulators, or electromyography (EMG). Numerous techniques have been proposed using one or a combination of the above modalities. However, application of these techniques is limited by unavailability of CT, MRI, and EMG equipment as well as a paucity of trained physicians in US-guided procedures in many pain treatment centers throughout the United States. Fluoroscopy, however, is more widely available in this setting. This study utilized a cadaveric specimen to confirm proper needle placement for piriformis or peri-sciatic injection utilizing the previously documented landmarks for fluoroscopic guidance as described by Betts. An anteroposterior of the pelvis with inclusion of the acetabular region of the hip and the inferior aspect of the sacroiliac joint was obtained. The most superior-lateral aspect of the acetabulum and the inferior aspect of the sacroiliac joint were identified. A marker was placed one-third of the distance from the acetabular location to the inferior sacroiliac joint, indicating the target location. A 22-gauge, 3.5-inch spinal needle was directed through the gluteal muscles to the target location using intermittent fluoroscopic guidance. The posterior ileum was contacted and the needle was withdrawn 1 –2 mm. This approach found the needle within the piriformis muscle belly 2 –3 cm lateral to sciatic nerve. The present study was the first study, to our knowledge, that has confirmed the intramuscular position of the needle within the piriformis muscle of a cadaveric specimen using these anatomic landmarks and fluoroscopic guidance. Key words: piriformis syndrome, back pain, fluoroscopy, sciatica