Amyloid Biopsy During Endoscopic Carpal Tunnel Release: A Comparison of Tenosynovial and Antebrachial Fascia Specimens.

PURPOSE: Indications and techniques for biopsy to detect amyloid deposition during carpal tunnel release are evolving. Despite the popularity of endoscopic carpal tunnel release (ECTR), there is concern that this technique may be less able to detect amyloid. Our purpose was to compare the incidence of amyloid deposition detected during ECTR using two different biopsy sources: tenosynovial tissue and antebrachial fascia of the distal forearm.

METHODS

This was a single-center retrospective investigation involving two hand surgeons. All primary, elective ECTR cases in adult patients between March 2022 and September 2024 were included if they underwent isolated tenosynovial or antebrachial fascia biopsy. Baseline demographics and surgical case characteristics were recorded. The primary comparisons of interest were the incidence of amyloid deposition for the tenosynovial and antebrachial fascia groups.

RESULTS

A total of 195 cases were included. Eighty-seven percent were indicated for Tier 1 biopsy criteria. Of these cases, 145 (74%) underwent tenosynovial biopsy and 50 (26%) underwent antebrachial fascia biopsy. Mean age was 68 years, and 43% were women. Baseline demographics were similar between the groups, including mean age (67 vs 69 years) and the percentage of cases with diabetes (21% vs 26%). Overall, 27% of the included cases had evidence of amyloid deposition detected on biopsy performed during ECTR. Cases that had a tenosynovial biopsy had a significantly higher incidence of amyloid deposition (33%) compared with cases that underwent isolated antebrachial fascia biopsy (12%).

CONCLUSIONS

For primary ECTR cases, tenosynovial biopsy results in a significantly higher incidence of amyloid deposition (33%) compared with antebrachial fascia specimens (12%). Although open carpal tunnel release remains the gold standard for biopsy, if ECTR is being performed, biopsies should be obtained from the tenosynovial tissue rather than antebrachial fascia.

TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.