Piriformis syndrome (PS) is an uncommon cause of sciatica that involves buttock pain referred to the leg. Diagnosis is often difficult, and it is one of exclusion due to few validated and standardized diagnostic tests. Treatment for PS has historically focused on stretching and physical therapy modalities, with refractory patients also receiving anesthetic and corticosteroid injections into the piriformis muscle origin, belly, muscle sheath, or sciatic nerve sheath. Recently, the use of botulinum toxin (BTX) to treat PS has gained popularity. Its use is aimed at relieving sciatic nerve compression and inherent muscle pain from a tight piriformis. BTX is being used increasingly for myofascial pain syndromes, and some studies have demonstrated superior efficacy to corticosteroid injection. The success of BTX in treating PS supports the prevailing pathoanatomic etiology of the condition and suggests a promising future for BTX in the treatment of other myofascial pain syndromes.

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Objective:To compare the efficacy of ultrasound-guided hyaluronic acid (HA) versus leukocyte-poor platelet-rich plasma (LP-PRP) injection in the treatment of glenohumeral osteoarthritis.Design:Double-blind randomized controlled trial.Setting:Academic institution.Patients:Seventy patients with chronic glenohumeral osteoarthritis were randomly assigned to receive a single injection of HA (n = 36) or LP-PRP (n = 34).Interventions:Leukocyte-poor platelet-rich plasma was processed using Harvest/TerumoBCT Clear PRP kits. Ultrasound-guided injections of 6 mL HA or 6 mL LP-PRP into the glenohumeral joint were performed. Patients, the injecting physician, and outcomes assessor were blinded to treatment assignments.Main outcome measures:Shoulder Pain and Disability Index (SPADI), American Shoulder and Elbow Surgeons (ASES) score, current/average numerical rating scale (NRS) pain scores, satisfaction, and side effects were assessed at the 5 follow-up time points over 12 months.Results:Baseline characteristics were similar between groups. There were no significant between-group differences regarding SPADI, ASES, and current/average NRS pain scores at any time point up to 12 months postinjection (P > 0.05). However, significant improvements in SPADI, ASES, and current/average NRS pain scores were observed in both groups starting at 1 or 2 months (P < 0.01, P < 0.01, P < 0.001, and P < 0.01, respectively). These improvements were observed regardless of osteoarthritis severity. For patients who received LP-PRP, there was no effect of platelet yield on outcomes. Side effect and satisfaction rates were similar between groups.Conclusions:There were no differences in pain and functional outcomes after a single injection of LP-PRP versus HA. However, significant improvements in pain and function were observed after both treatments in patients with glenohumeral osteoarthritis.