Exploring the role of biopsy-proven diabetic axonal neuropathy in outcomes of carpal tunnel release in diabetic and non-diabetic populations

Carpal tunnel release outcomes in diabetic and non-diabetic patients are conflicting, possibly due to lack of differentiating patients with axonal neuropathy and those without axonal neuropathy. Sixty-five diabetic and 106 non-diabetic patients who failed conservative treatment and then underwent carpal tunnel release from 2015 to 2022 were selected from a hand surgeon’s patient database. Diagnosis was established with parameters established with the CTS-6 Evaluation Tool, and electrodiagnosis when indicated. Patient outcomes were evaluated using preoperative and postoperative Disabilities of Arm Shoulder and Hand (DASH), Brief Pain Inventory (BPI), Boston Carpal Tunnel Questionnaire, Numeric Pain Scale, and Wong-Baker Pain Scale. Postoperative evaluations were taken 6 months to a year post-surgery. Skin biopsies for nerve fiber density and morphology were taken from 50 diabetic patients. Another 50 were taken from non-diabetic patients with carpal tunnel syndrome and served as controls. Biopsy-proven axonal neuropathy was used as a confounding variable in the assessment of diabetic patients’ recovery When comparing diabetics with biopsy-proven axonal neuropathy to diabetics without axonal neuropathy, the recovery outcomes are increasingly better for diabetics without neuropathy. Diabetics with biopsy-proven neuropathy have an improvement in recovery outcomes as well; however, not to the level of non-diabetics. Patients with increased scale scores or clinical suspicion for axonal neuropathy can be offered the option of undergoing a biopsy, and counseled about the risks for increased time to meet outcomes comparable to non-diabetics and diabetics without axonal neuropathy. ●Outcomes of carpal tunnel release in diabetic and non-diabetic patients are conflicting.●Lack of differentiation between patients with axonal neuropathy and those without axonal neuropathy may create conflicting outcomes.●A longer time is required for patients with axonal neuropathy to see outcomes comparable to patients without axonal neuropathy.