Outcomes of the Starfish Procedure using Muscle Transfer for Independent Digital Control of a Myoelectric Prosthesis
Keith M Nord, MD1; Casey M. Sabbag, MD1; Sahitya K Denduluri, MD2; Bryan J. Loeffler, MD3; R. Glenn Gaston, MD1
1OrthoCarolina, Charlotte, NC; 2OrthoCarolina, Charlotte, CA; 3Hand Center, OrthoCarolina, Charlotte, NC
Introduction: Utilizing surface electromyography has revolutionized the prosthetic options for patients with upper extremity amputations, but patients with partial hand amputations have remained a challenge. The Starfish Procedure is a novel surgical technique that involves transferring intrinsic hand muscles to a subcutaneous location to allow immediate independent digital control of a myoelectric prosthesis. We report the outcomes of our cohort of patients treated with the Starfish Procedure.
Materials & Methods: Fifteen patients underwent the Starfish procedure and met eligibility criteria. All patients had a postoperative evaluation with Ottobock Myoboy to determine if they had viable signals from interossei transfers. All patients completed a specialized survey for amputees, depression, and PTSD surveys. DASH and VAS pain scores were obtained for all patients.
Results: All patients had recordable myoelectric signals at each muscle transfer. Patients report using their prosthesis an average of 5.5 hours per day and 5.5 days per week. The average DASH score prior to surgery was 59.2 and after surgery was 39.2. VAS Pain scores were 3.5 for residual limb pain and 3.4 for phantom pain. Nine patients reported phantom sensation, 8 reported phantom pain, and no patients had evidence of neuroma at final follow-up. Mean follow-up was 2.1 years. Five patients had positive PTSD-Q5 surveys and 6 patients had moderate to severe depression ratings at most recent follow up. Patients reported being extremely satisfied or very satisfied with the appearance, grasp, release, and overall function of their prosthesis. The most common functional activities that the prosthesis allowed patients to perform include self-grooming, work, recreation, meal preparation and eating. Prior to the injury 66.7% of patients were employed. After prosthesis fitting, 75% of previously employed patients were able to return to work.
Conclusions: Upper extremity amputations distal to the forearm previously posed an engineering and anatomic challenge. The Starfish procedure provides a solution to this by creating superficial myoelectric signals that allow intuitive and independent finger control. At 2-year follow up, patients have a high satisfaction rate, consistent myoelectric prosthetic use and improved DASH scores. Depression and PTSD remain significant clinical factors even after surgery. A large percentage of patients are able to return to gainful employment with the new prosthesis.
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