Differences in the Incidence of Amyloid Deposition in Biopsies Performed During Bilateral Carpal Tunnel Release

Biopsy during carpal tunnel release (CTR) to assess for amyloid deposition may be indicated in older patients with bilateral symptoms. There is a paucity of prior investigations comparing the results of bilateral CTR biopsy samples. Our purpose was to compare differences in the incidence of amyloid deposition detected during bilateral CTR.

We reviewed primary, bilateral (staged or simultaneous) CTR cases from a single-surgeon between March 2022 and September 2024 during which a biopsy was obtained from both sides. The presence of amyloid deposition was determined using Thioflavin T and/or Congo Red staining using established institutional protocols. Baseline demographics were recorded, and the results of bilateral biopsies were compared to assess for disparate results.

A total of 65 patients underwent bilateral CTR where a biopsy was obtained during both procedures. Mean age was 67 years, and 42% were women. Of the 65 included patients, 8 (12%) had evidence of amyloid deposition on at least one biopsy. Six patients overall (9%) had disparate biopsy results, accounting for 75% of positive cases. In these six patients, four (67%) had evidence of amyloid deposition during the first biopsy and no evidence of amyloid on the second biopsy. Two of six patients (33%) had no evidence of amyloid deposition during the first biopsy but did have evidence of amyloid on the second biopsy.

Biopsy results differ with respect to amyloid deposition in 9% of bilateral CTR cases. Seventy-five percent of patients with evidence of amyloid deposition on at least one extremity will have discordant bilateral biopsy results. In patients where the index biopsy is positive during a CTR, a contralateral biopsy may not be necessary. However, in patients where the index biopsy is negative for amyloid deposition, we recommend repeating the biopsy during the second (contralateral) CTR.

Prognostic II.