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.

Cluneal neuropathy: Background, diagnosis, and treatment.

BACKGROUND AND AIMS: Cluneal neuropathy is encompassed by three distinct clinical entities. Superior, middle, and inferior cluneal neuralgia make up the constellation of symptoms associated with cluneal neuropathy. Each has its own variable anatomy. MATERIALS AND METHODS: We compiled a narrative review including a review of available literature. We conducted searches on PubMed/MEDLINE, Embase and Google Scholar on the topics of cluneal neuropathy and treatment therein. RESULTS: We collected source articles regarding original descriptions of the disease entities in addition to articles focused on treatment. DISCUSSION: Adjusted incidence rates of superior cluneal neuropathy are 1.6%-11.7%. Accurate diagnosis remains challenging due to the lack of standardized criteria and the aforementioned variability. Treatment may include therapeutic nerve blocks, ablative techniques, neuromodulation, and surgical decompression. Gaps including those related to true incidence and work up exist. Outcomes from interventional studies are limited and mixed due to significant population heterogeneity and non-standardized treatment approaches coupled with very small sample sizes.

Postoperative pain and the need for intervention after sacrospinous ligament hysteropexy compared to colpopexy: a retrospective cohort study.

OBJECTIVES: To compare postoperative pain between patients undergoing sacrospinous ligament colpopexy (SSLF) and hysteropexy (SSLH). METHODS: This was a retrospective cohort study of all patients undergoing native tissue SSLF and SSLH between January 2013 and March 2020. The electronic medical record was queried for demographic and perioperative data until the postoperative visit. The primary outcome was a composite incidence of any of the following: telephone calls, urgent office visits, additional analgesic prescriptions and need for intervention for pain in the buttocks, posterior thigh or perirectal area. Secondary outcomes were the incidence of persistent pain at the postoperative visit and perioperative risk factors associated with reported pain. RESULTS: A total of 406 patients met inclusion criteria (308 SSLF, 98 SSLH). The composite pain outcome was seen in 99 patients (24.4%; 95% CI 20.5%-28.8%), and there was no statistical difference between cohorts. Persistent pain was seen in 15.6% and 13.3% of SSLF and SSLH patients at 6 weeks (p = 0.58). Twelve patients (3.0%) underwent interventions for pain, including physical therapy (2), trigger point injections (5) and suture release (5). Compared to SSLF patients, SSLH patients were more likely to need interventions (7 [7.1%] vs. 5 [1.6%], p = 0.005) and office visits (14 [14.3%] vs. 13 [4.2%], p = 0.0005) for pain. CONCLUSIONS: There was no difference in the overall incidence of postoperative pain between patients who underwent SSLF or SSLH. However, patients who underwent hysteropexy were more likely to need intervention and office evaluation for postoperative pain.

Clinical features of middle cluneal nerve entrapment neuropathy.

BACKGROUND: Entrapment of the middle cluneal nerve (MCN), a peripheral nerve in the buttock, can elicit low back pain (LBP). We examined the epidemiology, clinical course, and treatment of MCN entrapment (MCN-EN). METHODS: Among 383 LBP patients who visited our institute, 105 were admitted for intractable LBP. They were 42 men and 63 women; their average age was 64 years. Based on clinical symptoms, palpation, and the effects of MCN block, we suspected MCN-EN in these 105 patients, 50 of whom are our study subjects. Their treatment outcomes were assessed at the time of discharge and at follow-up visits. RESULTS: MCN-EN was diagnosed in 50 of the 383 patients (13.1%) and they were hospitalized. In 43 (11.2%), MCN-EN was associated with other diseases (superior cluneal nerve entrapment, n = 21, sacroiliac joint pain, n = 9, other, n = 13). At the time of discharge, the symptoms of patients with LBP due to MCN-EN were significantly improved by repeat MCN blocks. In 7 of the 383 patients (1.8%), LBP was improved by only MCN blocks; 5 of them had reported leg symptoms in the dorsal part of the thigh. After discharge, 22 of the 50 hospitalized patients required no additional treatments after 2-5 blocks; 19 required only conservative treatment, and 9 underwent microsurgical release of the MCN. CONCLUSIONS: We confirmed MCN-EN in 50 of 105 patients admitted for intractable LBP. Repeat MCN blocks were effective in 22 patients; 19 required additional conservative treatment, and 9 underwent surgery. Buttock pain radiating to the posterior thigh was an MCN-EN symptom that has been diagnosed as pseudo-sciatica. Before subjecting patients with intractable LBP to surgery, the presence of MCN-EN must be ruled out.

High-frequency thermal coagulation to treat middle cluneal nerve entrapment neuropathy.

OBJECTIVE: Middle cluneal nerve entrapment (MCN-E) around the sacroiliac joint can elicit low back pain (LBP). Pain control can be obtained with anesthetic nerve blocks; however, when their effectiveness is transient, surgical release may be necessary. We investigated the efficacy of radiofrequency thermocoagulation (RFTC) in patients with MCN-E. METHODS: Between December 2018 and August 2019, 11 consecutive patients (4 men, 7 women; mean age 76.4 years) with intractable medial buttock pain due to MCN-E underwent MCN RFTC. The mean symptom duration was 49.5 months; pre-RFTC local MCN blocks provided pain relief for a mean of 7.7 days. The severity of pain in the medial buttock due to MCN-E was recorded before and 2, 6, 12, and 24 weeks after RFTC on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). RESULTS: All patients reported pain alleviation; there were no complications. While there was a significant difference in the pre- and post-RFTC treatment NRS (p < 0.05), the RDQ scores were significantly lower only after 12 weeks. The duration of pain relief was significantly prolonged by RFTC (p < 0.05). Two patients suffered pain relapse 10 weeks post-RFTC; pain alleviation was obtained by re-RFTC performed 2 weeks after pain recurrence. Two other patients relapsed 20 and 21 weeks post-RFTC; their symptoms also disappeared by MCN block administered 24 weeks after they had undergone RFTC. CONCLUSION: RFTC may safely control intractable LBP due to MCN-E.

Pain Syndromes Secondary to Cluneal Nerve Entrapment.

PURPOSE OF REVIEW: The purpose of this review is to provide an overview of the cluneal nerves, present a summary of pain syndromes secondary to clunealgia, and evaluate current literature for diagnostic and treatment modalities. RECENT FINDINGS: Multiple trials and studies have reported success with numerous modalities ranging from nerve blocks, neuroablation, and even peripheral neuromodulation with varying degrees of clinical benefit. Cluneal nerve entrapment or chronic impingement can cause buttock pain or referred pain to nearby areas including the lower back, pelvic area, or even the lower extremities. Clunealgias and associated pain syndromes can often be challenging to diagnose and differentiate. An appreciation of the pathophysiology of clunealgias can assist with patient selection for interventional pain strategies targeted towards the cluneal nerves, including nerve blocks, neuroablation, and peripheral neuromodulation. More research is needed to better delineate the efficacy of these procedures for clunealgias.

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

BACKGROUND: The causes of low back and buttock pain are variable. Elsewhere, we presented a surgical technical note addressing the gluteus medius muscle (GMeM) pain that elicited buttock pain treatable by surgical decompression. Here, we report minimum 2-year surgical outcomes of GMeM decompression for intractable buttock pain. METHODS: Between January 2014 and December 2015, we surgically treated 55 consecutive patients with a GMeM pain. Of these, 39 were followed for at least 2 years; they were included in this study. Their average age was 69.2 years; 17 were men and 22 were women. The affected side was unilateral in 24 patients and bilateral in the other 15 (total 54 sites). The mean follow-up period was 40.0 months (range 25-50 months). The severity of pre- and post-treatment pain was recorded on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). RESULTS: Of the 39 patients, 35 also presented with leg symptoms. They were exacerbated by walking in all 39 patients and by prolonged sitting in 33 patients; 19 had a past history of lumbar surgery and 4 manifested failed back surgery syndrome. Repeat surgery for wider decompression was performed in 5 patients due to pain recurrence 15.8 months after the first operation. At the last follow-up, the symptoms were significantly improved; the average NRS fell from 7.4 to 2.1 and the RDQ score from 10.5 to 3.3 (p < 0.05). CONCLUSIONS: When diagnostic criteria are met, GMeM decompression under local anesthesia is a useful treatment for intractable buttock pain.

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.

Variability of ischiofemoral space dimensions with changes in hip flexion: an MRI study.

OBJECTIVE: The primary aim of this study was to determine if ischiofemoral space (IFS) dimensions vary with changes in hip flexion as a result of placing a bolster behind the knees during magnetic resonance imaging (MRI). A secondary aim was to determine if IFS dimensions vary between supine and prone hip neutral positions. DESIGN: The study employed a prospective design. SETTING: Sports medicine center within a tertiary care institution. PARTICIPANTS: Five male and five female adult subjects (age mean = 29.2, range = 23-35; body mass index [BMI] mean = 23.5, range = 19.5-26.6) were recruited to participate in the study. METHODS: An axial, T1-weighted MRI sequence of the pelvis was obtained of each subject in a supine position with their hips in neutral and flexed positions, and in a prone position with their hips in neutral position. Supine hip flexion was induced by placing a standard, 9-cm-diameter MRI knee bolster under the subject's knees. The order of image acquisition (supine hip neutral, supine hip flexed, prone hip neutral) was randomized. The IFS dimensions were then measured on a separate workstation. The investigator performing the IFS measurements was blinded to the subject position for each image. MAIN OUTCOME MEASUREMENTS: The main outcome measurements were the IFS dimensions acquired with MRI. RESULTS: The mean IFS dimensions in the prone position were 28.25 mm (SD 5.91 mm, standard error mean 1.32 mm). In the supine hip neutral position, the IFS dimensions were 25.1 (SD 5.6) mm. The mean difference between the two positions of 3.15 (3.6) mm was statistically significant (95 % CI of the difference = 1.4 to 4.8 mm, t19 = 3.911, p = .001). The mean IFS dimensions in the hip flexed position were 36.9 (SD 5.7) mm. The mean difference between the two supine positions of 11.8 (4.1) mm was statistically significant (95 % CI of the difference = 9.9 to 13.7 mm, t19 = 12.716, p < .001). CONCLUSIONS: Our findings demonstrate that the IFS measurements obtained with MRI are dependent upon patient positioning with respect to hip flexion and supine versus prone positions. This finding has implications when evaluating for ischiofemoral impingement, an entity resulting in hip and/or buttock pain secondary to impingement of the quadratus femoris muscle within a pathologically narrowed IFS. One will need to account for patient hip flexion and supine versus prone positioning when evaluating individuals with suspected ischiofemoral impingement.

Decompression of the gluteus medius muscle as a new treatment for buttock pain: technical note.

PURPOSE: The clinical features and etiology of low back pain and buttock pain remain poorly understood. We report ten patients with buttock pain who underwent gluteus medius muscle (GMeM) decompression under local anesthesia. METHODS: Between December 2012 and November 2013 we surgically treated ten patients (four men, six women; mean age 65.1 years) for buttock pain. The affected side was unilateral in seven and bilateral in three patients (total sites, n = 13). The interval from symptom onset to treatment averaged 174 months; the mean postoperative follow-up period was 24 months. Decompression of the tight gluteal aponeurosis over the GMeM was performed under local anesthesia. Assessment of the clinical outcomes was on the numeric rating scale (NRS) for low back pain (LBP), the Japanese Orthopedic Association (JOA) score, and the Roland-Morris Disability Questionnaire (RDQ) score before and at the latest follow-up after treatment. RESULTS: There were no intraoperative surgery-related complications. The buttock pain of all patients was improved after surgery; their NRS decreased from 7.0 to 0.8 and JOA and RMDQ scores indicated significant improvement (p < 0.05). CONCLUSION: In patients with buttock pain, pain around the GMeM should be considered as a causative factor. Less invasive surgery with cutting and opening of the tight gluteal aponeurosis over the GMeM under local anesthesia yielded excellent clinical outcomes.

A Case of Symptomatic Multiple Tarlov Cysts Treated with Microsurgical Wrapping Technique -Efficacy and Limitation of Surgical Procedure.

Tarlov cysts (TCs) rarely cause clinical symptoms, such as leg pain, buttock pain, and bladder/bowel dysfunction. Surgery is considered when these symptoms persist despite medical treatments. Among several surgical procedures, microsurgical wrapping (MSW) is a relatively novel, simple technique with few complications, including cerebrospinal fluid leakage. Herein, we report a case of multiple TCs treated with MSW and present the mechanism of symptoms generated by TC and the procedure's limitations. A 58-year-old man complained of severe right leg and buttock pain for 3 months and was admitted to our hospital. His symptoms aggravated with sitting and standing and improved with the prone position. Spinal magnetic resonance imaging (MRI) demonstrated multiple sacral cysts containing intense cerebrospinal fluid. The cysts connect to the right S3 and S4 nerve roots. He was treated conservatively with medications; however, his symptoms were not improved. Therefore, MSW was performed for TCs connected to the S3 and S4 roots. The postoperative course was uneventful, and cerebrospinal fluid leakage did not occur. MRI performed 1 year after the operation demonstrated no recurrence of the TCs, and his leg pain was completely relieved; however, the buttock pain remained. MSW for TCs is effective for symptoms of adjacent nerve root compression; however, repairing the damaged nerve root in TCs is sometimes difficult. This may be a limitation of present surgical interventions because these symptoms may be difficult to treat even with other interventions.

Current and future advances in practice: tendinopathies of the hip.

Tendinopathy describes persistent tendon pain and loss of function related to mechanical loading. Two common hip tendinopathies seen in practice are gluteal tendinopathy and proximal hamstring tendinopathy. Both conditions can be frustrating for patients and clinicians due to the delay in diagnosis, significant disability caused and lack of response to common treatments. Tendinopathy is a clinical diagnosis and can most often be made using findings from the patient interview and pain provocation tests, without the need for imaging. Specific education and progressive exercise offer a low-risk and effective option for gluteal tendinopathy and result in greater rates of treatment success than corticosteroid injection, both in the short term (8 weeks) and at 1 year. Proximal hamstring tendinopathy is a common, but less researched, and under-recognized cause of persistent ischial pain. As research on proximal hamstring tendinopathy is limited, this review summarizes the available evidence on diagnosis and treatment following similar principles to other well-researched tendinopathies.

A Novel Treatment of Fascial Pain With Glucopuncture: Three Clinical Cases.

The fascial system (FS) represents a sophisticated and intricate network within the human body, comprising both superficial and deep fascial layers. Disruptions or dysfunctions within this system have been implicated in a variety of musculoskeletal (MSK) disorders and pain syndromes. Specifically, fascial tightness has been associated with diminished range of motion and localized pain. Glucopuncture, a novel therapeutic approach, involves the administration of 5% dextrose injections directly into the fascial layers, such as the superficial fascia, to address these issues. This article presents a case series involving three patients who underwent palpation/ landmark-guided glucopuncture for the treatment of superficial fascial dysfunction. The first case involves a 45-year-old male with a nine-month history of left groin pain, who experienced significant pain relief following glucopuncture below the inguinal ligament, with complete resolution of symptoms within four weeks. The second case describes a 36-year-old female suffering from left arm and neck pain for two years, who reported gradual pain alleviation over six weeks after receiving multiple injections in the fasciae of the neck, scapula, and lateral aspect of the triceps muscle. The final case involves a 67-year-old female with a six-month history of low back and buttock pain, who showed improvement after four weeks following multiple injections in the fasciae of the low back, lumbar region, and buttocks. These cases highlight the potential of palpation-guided glucopuncture as a simple, cost-effective method for modulating regional pain caused by superficial fascial dysfunction. However, further research is necessary to fully ascertain the efficacy and safety of glucopuncture for treating fascial dysfunction.

Easy to treat when the diagnosis is made: Three cases of clunealgia and the advantage of ultrasonography.

In this article, we present three cases of clunealgia admitted with low back pain. Their pain relieved with superior cluneal nerve block. The posterior side of the iliac crest, which is the location where the superior cluneal nerve passes, was identified using a high-frequency linear transducer. The drug injected separates the erector spinae muscle and thoracolumbar fascia and accumulates between these two structures. All patients were discharged with a complete pain relief. This report highlights the fact that superior cluneal nerve entrapment should be kept in mind in patients with low back pain and that ultrasound guidance can correctly identify the infiltration and eliminate anesthetization of other surrounding structures.

Evaluation of the efficacy of Superior Cluneal Nerve Block in low back pain: A prospective observational study.

INTRODUCTION: Superior cluneal nerve (SCN) entrapment giving rise to low back pain (LBP) remains undiagnosed many times; in this clinical study authors have evaluated therapeutic role of lidocaine injection of SCN for low back pain relief in patients with SCN entrapment. METHODS: The present study was a prospective, observational study; 25 patients with unilateral LBP over the iliac crest and buttock for more than six months not responding to conservative measures were included in this clinical trial. SCN lidocaine injection was done under fluoroscopy guidance; patients having more than 50% reduction in numeric rating scale (NRS) score, for at least 2 h following SCN injection, were enrolled in the study and followed for 6 months. The primary outcome measure was severity of LBP, measured by NRS score. Secondary outcome measures were percentage pain relief; Oswestry Disability Index (ODI) score, reduction of analgesic usage, DSM-IV score for psychological assessment. All these assessments were done prior to the procedure and at 2 weeks, 1, 3 and 6 months after the procedure. RESULTS: A significant reduction in the NRS scores was observed at 2 weeks, 1, 3 and 6 months after SCN lidocaine injection as compared to the baseline (P value < 0.05); authors also observed a significant pain relief and significantly reduced ODI scores, analgesic consumption and DSM scores compared to the baseline values (P value < 0.05). CONCLUSION: A single SCN lidocaine injection provided significant pain relief in LBP patients with SCN entrapment for a period of 6 months.

Superior and Middle Cluneal Nerve Entrapment: A Cause of Low Back and Radicular Pain.

BACKGROUND: The superior and middle cluneal nerves are sources of low back, buttock, and leg pain. These nerves are cutaneous branches of the lateral branches of the dorsal rami of T11- S4. Pain arising from entrapment or dysfunction of one or more of these nerves is called "cluneal nerve syndrome." A clear understanding of the anatomy underlying cluneal nerve syndrome and its treatment has been hampered by the very small size of the cluneal nerves and their complex, varying anatomy. Because of differing methods and foci of investigation, the literature regarding cluneal nerves has been confusing and even contradictory. OBJECTIVES: This paper provides a thorough critical literature review of cluneal nerve anatomy and implications for therapy. STUDY DESIGN: A modified scoping review. METHODS: The bibliographic trail of English language papers on the anatomy and treatment of cluneal nerve syndrome was used to resolve the contradictions that have appeared in some of the anatomic descriptions and, where applicable, to examine their implications for therapy. RESULTS: Recent anatomic and surgical investigations confirm a wider than previously realized range of central nervous system origins of these peripheral nerves, explaining why cluneal nerve dysfunction can cause a wide array of symptoms, including low back, buttock, and/or leg pain or "pseudosciatica." CONCLUSIONS: Cluneal nerve syndrome is characterized by a triad of pain, tender points, and relief with local anesthetic injections. The pain is a deep, aching, poorly localized low back pain with variable involvement of the buttocks and/or legs. Tender points are localized at the iliac crest or caudal to the posterior superior iliac spine. Muscle weakness and dermatomal sensory changes are absent in cluneal nerve syndrome. If the pain returns after injections, neuroablation, nerve stimulation, or surgical release may be needed.

Proximal Hamstring Tendinopathy: A Systematic Review of Interventions.

BACKGROUND: Proximal hamstring tendinopathy affects athletic and non-athletic populations and is associated with longstanding buttock pain. The condition is common in track and field, long distance running and field-based sports. Management options need to be evaluated to direct appropriate clinical management. PURPOSE/HYPOTHESIS: To evaluate surgical and non-surgical interventions used in managing proximal hamstring tendinopathy. STUDY DESIGN: Systematic review. METHODS: Electronic databases were searched to January 2019. Studies (all designs) investigating interventions for people with proximal hamstring tendinopathy were eligible. Outcomes included symptoms, physical function, quality of life and adverse events. Studies were screened for risk of bias. Reporting quality was assessed using the Cochrane Risk of Bias Tool (Randomized Controlled Trials [RCT]) and the Joanna Briggs Institute Checklist (Case Series). Effect sizes (Standard mean difference or Standard paired difference) of 0.2, 0.5 and 0.8 were considered as small, medium and large respectively. Overall quality of evidence was rated according to GRADE guidelines. RESULTS: Twelve studies (2 RCTs and 10 case series) were included (n=424; males 229). RCTs examined the following interventions: platelet-rich plasma injection (n=1), autologous whole-blood injection (n=1), shockwave therapy (n=1) and multi-modal intervention (n=1). Case series included evaluation of the following interventions: platelet-rich plasma injection (n=3), surgery (n=4), corticosteroid injection (n=2), multi-modal intervention + platelet-rich plasma injection (n=1). Very low-level evidence found shockwave therapy was more effective than a multi-modal intervention, by a large effect on improving symptoms (-3.22 SMD; 95% CI -4.28, -2.16) and physical function (-2.42 SMD; 95% CI-3.33, -1.50) in the long-term. There was very low-level evidence of no difference between autologous whole-blood injection and platelet-rich plasma injection on physical function (0.17 SMD; 95% CI -0.86, 1.21) to (0.24 SMD; 95% CI -0.76, 1.24) and quality of life (-0.04 SMD; 95%CI -1.05, 0.97) in the medium-term. There was very low-quality evidence that surgery resulted in a large reduction in symptoms (-1.89 SPD; 95% CI -2.36, -1.41) to (-6.02 SPD; 95% CI -8.10, -3.94) and physical function (-4.08 SPD; 95%CI -5.53, -2.63) in the long-term. CONCLUSIONS: There is insufficient evidence to recommend any one intervention over another. A pragmatic approach would be to initially trial approaches proven successful in other tendinopathies. LEVEL OF EVIDENCE: Level 2a.

A Multicenter Retrospective Analysis of the Long-Term Efficacy and Safety of a Novel Posterior Sacroiliac Fusion Device.

BACKGROUND: Sacroiliac joint (SIJ) pathology is a cause of low back pain that may be difficult to diagnose and challenging to treat. Open and minimally invasive (MI) lateral approach fusions have been used to treat sacroiliitis over the past two decades. A novel MI posterior approach SIJ fusion technique utilizes a posteriorly placed transfixing device with single point S1/S2 level or mid-segment SIJ fixation (LinQ procedure). Current efficacy and safety data for this novel procedure are lacking. OBJECTIVE: To review multicenter retrospective 12 months or greater outcomes data in patients receiving the LinQ procedure, with sub-analysis of patients with prior lumbar fusions. METHODS: Patients with sacroiliitis refractory to conservative care with short-term benefit from diagnostic local anesthetic SIJ injections receiving MI posterior approach SIJ fusion with allograft were included from different centers including both academic and private practice. Numeric rating scale (NRS) scores at baseline (pre-procedural) and most recent follow-up were reviewed across three institutions. RESULTS: Of 110 patients who received MI SIJ fusion, 50 patients had sufficient data for evaluation of outcomes at least 12 months post-implant. The average time out from implant at follow-up was 612.2 days for all unique patients. The average NRS was 6.98 pre-fusion and 3.06 at last follow-up. Twenty-four patients had prior lumbar surgery of which 17 had prior lumbar fusions. Average NRS for this subset was 6.85 at baseline and 2.86 at last follow-up with an average follow-up of 613.2 days out from implant. No major adverse events or complications were associated with any of the 50 implants. CONCLUSION: Real-world evidence suggests that MI posterior SIJ fusion with the LinQ procedure is a viable approach for medically refractory sacroiliitis management with long-term efficacy and safety. Further prospective studies are needed to fully evaluate this technique.

Atypical Unilateral Sacroiliitis Secondary to Mechanical Stress Injury.

We report for the first time a case of atypical unilateral sacroiliitis secondary to mechanical stress injury. Unilateral sacroiliitis can be caused by a variety of etiologies. The first diagnosis to rule out is infection since it requires urgent treatment to avoid its serious consequences. Spondyloarthritis can be manifested by unilateral sacroiliitis in its early stage. Sacral fractures should always be looked for on the imaging modalities performed. In our case, no signs of infection or systemic disease were found. No fracture was seen on the imaging examinations and we had negative cultures on the computed tomography-guided biopsy realized. A history of mechanical stress was the only clue found suggesting the diagnosis of a probable stress related sacroiliitis. A thorough review of the literature will be provided stating the different causes of sacroiliitis described till now, with discussion of this new reported entity.