The rise in popularity of ECTR has not been without resistance. Critics have questioned the potential benefits of an alternative treatment to OCTR, a well-established, safe, and simple surgical procedure, leading some to cite ECTR as a triumph of technology over reason. The primary concern of ECTR is damage to anatomic structures secondary to limited visualization of the full surgical field. Fear of damaging major neurovascular structures including the median nerve, the palmar cutaneous branch, the thenar motor branch, the ulnar nerve, and the superficial palmar arch are potentially catastrophic complications which lead many to avoid ECTR altogether. Incomplete release of the TCL is another concern arising from the limited visualization. Gould et al provided a comprehensive list of reasons for their concern with ECTR, which includes anatomic concerns such as motor branch variations, presence of recurrent or bifid nerves, persistent median arteries, and presence of the superficial palmar arch or other extraneous musculotendinous units within the canal, as well as ancillary issues including systemic disease such as amyloidosis, extensive tenosynovitis or calcifications, or mass effect in the form of cysts or schwannomas, the sum of which prompt the authors to favor OCTR.
Clearly, these concerns have not precluded all to avoid ECTR. In direct response to the article by Gould et al, Wagner et al offered a counterargument about the safety of ECTR in the hands of experienced surgeons. The authors cite previous studies demonstrating improved outcomes and fewer complications for procedures performed by higher volume surgeons at higher volume centers, which is the case for complex microsurgical procedures such as free flaps and finger replantation and more common procedures such as hip and knee arthroplasty. Surgeon experience is vital for recognizing anatomic variants and atypical causes both while diagnosing carpal tunnel syndrome and while performing ECTR (Figure 3), allowing the surgeon to take appropriate safety measures when necessary. Thus, the authors argue that although ECTR may be technically more difficult, it should still be pursued if there is potential for improved outcomes over traditional OCTR. A learning curve certainly exists for ECTR. Although an exact number of cases to master the technique have not been determined, studies have shown a higher rate of conversion to OCTR in the early stages of a surgeon's practice. Some studies have shown a nonsignificant higher incidence of complications in early stages, although other studies have not.[14,15]
Intraoperative endoscopic images demonstrating (A), transligamentous recurrent motor branch and (B) subligamentous recurrent motor branch (Reprinted from Plastic & Reconstructive Surgery Global Open, 5(9), Wolfswinkel EM, Hoang D, Kulber DA, Anatomic Variations of the Median Nerve Identified during Endoscopic Carpal Tunnel Release with STRATOS, 1 to 2, 2017, with permission from Wolters Kluwer Health, Inc).
J Am Acad Orthop Surg. 2022;30(7):292-301. © 2022 American Academy of Orthopaedic Surgeons