Chronic inflammation of the shoulder joint capsule and its associated structures can lead to clinically significant symptoms, including insidious onset of pain, and ultimately restricting range of motion. Although the underlying mechanism for adhesive capsulitis (AC) is not well defined, some studies suggest that fibroblast proliferation and thickening of the coracohumeral ligament (CHL) is a proposed mechanism for which AC and subsequent prolonged immobilization and symptoms present (1, 2, 3). Other studies suggest that it is due to a combination of capsular fibrosis and inflammation within the synovium, and other focus on the fact that thickening of the CHL is responsible for limiting external rotation in patients affected by adhesive capsulitis (1).

AC coined frozen shoulder by Codman in 1934 \[2), has an estimated prevalence of 2-3% in the general population, with ages 40-70 affected most commonly, and predominantly women. While the precise etiology remains undefined, it can be secondary to trauma or an idiopathic etiology and has been found to have an incidence as high as 20% in diabetic patients, with worse functional outcomes when compared to non-diabetic patients. Hypothyroidism and cerebrovascular disease have also been shown to be associated with an increased risk of developing AC (4). AC is typically a clinical diagnosis. However, both magnetic resonance and ultrasonography have consistently shown thickening of the CHL (1). Several studies have compared arthrographic evidence of findings in adhesive capsulitis, and many reported a thickening of the CHL in cases of frozen shoulder as compared to control subjects (2). In a study implementing shear-wave elastography (SWE), the CHL in patients diagnosed with adhesive capsulitis was thicker and stiffer (4).

Interventions aimed at improving AC and CHL damage, clinical symptomatology, as well as histopathological findings range from rest and physical therapy, local injections and hydrodilation, to advanced surgical interventions (4, 5). These surgical options include manipulation under anesthesia (MUA) and arthroscopic capsulotomy. MUA is an aggressive mobilization of the joint in an effort to lyse adhesions and to stretch the contracted glenohumeral capsule. Despite potential benefits, MUA has been associated with superior labral anterior and posterior (SLAP) lesions, bankart lesions, capsular tears, hemarthrosis, and even humeral or glenoid fractures (4). Arthroscopic capsulotomy allows for direct visualization of the CHL and confirmation of the diagnosis of AC, and several studies have shown improvement in pain relief as well as range of motion (4). However, patients who did not benefit from this intervention were women, typically over the age of 50, with a past medical history of diabetes mellitus. CHL resection has also been described as a potential treatment option for AC (6, 7), with current therapy limited to a surgical approach. Management of refractory disease through arthroscopic capsular release has been shown to improve pain and increase range-of-motion (8, 9, 4). A sequela of arthroscopic surgery is postoperative persistent AC, which some surgeons attempt to prophylactically prevent with adequate postoperative pain control so that the patient can participate in a physical therapy program. The potential limitations of current conservative management and IRB NUMBER: 2020-11998 IRB APPROVAL DATE: 11/17/2020 sequelae of surgical approaches have prompted additional novel therapies. International have researchers developed an ultrasound guided technique with a scalpel incision of the CHL to address this need. Scalpel use is not the standard of care for interventional musculoskeletal pain treatments and our team decided to improve this limitation. Blades and scalpels limit US visibility, thus marginalizing the safety of the procedure. Our team used a percutaneous, ultrasound visible, needle shaped, tissue cutting device to lesion the CHL while improving upon the potential safety concerns. The tool, TENEX®, is widely used by Pain physicians to perform percutaneous tenotomies and has been described in the management of various tendinous pathologies (10, 11, 12, 13, 14, 15).; this device was selected because the gross architectural similarities of tendon and ligament suggest that the CHL could be modified by this tool. Our novel procedure was performed on cadavers to provide proof of concept

The authors performed cadaveric dissection in 8 cadaveric shoulders with the hypothesis that sonographically guided percutaneous dissection will result in sectioning of the coracohumeral ligament. In this study we found that complete sectioning was reproducibly achieved in 7 minutes with approximately 250 passes of the device. This was the desired outcome for improving the shoulder ROM (16). This shows proof of concept and we want to perform this procedure in living subjects for validation. If the results are positive patients can have an outpatient procedure in the interventional pain clinic with desirable results. This cadaveric technique study has already been submitted to Pain Medicine journal for publication.

In addition to the above proof of concept above this procedure was performed in living subjects. A peer reviewed paper was submitted based on data from these subjects. 7 patients were selected for the publication as these patients had follow-ups as requested by the reviewer. In these patients the average improvement in external rotation was 40 degrees and the average abduction improvement was 31 degrees. All patients retained this improvement in shoulder ROM at follow-up visits. Of note, one patients follow-up visit was 116 after the procedure and her improvement in ROM was 60 and 110 in external rotation and abduction respectively. Given these outcomes the authors decided to do a prospective RCT.