Endoscopic Carpal Tunnel Release

Techniques, Controversies, and Comparison to Open Techniques

Jacques H. Hacquebord, MD; Jeffrey S. Chen, MD; Michael E. Rettig, MD

J Am Acad Orthop Surg. 2022;30(7):292-301.

Abstract and Introduction

Abstract

Endoscopic carpal tunnel release (ECTR) continues to rise in popularity as a treatment option for carpal tunnel syndrome. Numerous variations in technique and instrumentation currently exist, broadly classified into two-portal and single-portal techniques with antegrade and retrograde designs. ECTR is equally effective as open carpal tunnel release for alleviating symptoms of carpal tunnel syndrome with no differences in long-term outcomes. ECTR has an increased risk of transient nerve injury, whereas open carpal tunnel release has an increased risk of wound and scar complications. ECTR has higher direct costs but is associated with earlier return to work. ECTR is a safe and effective approach to carpal tunnel release in the hands of experienced surgeons.

Introduction

Carpal tunnel syndrome is the most common compressive peripheral neuropathy within the United States with an incidence of 1 to 3 cases per 1,000 patients per year and a prevalence as high as 5% in the general population.^[1,2] Its diagnosis carries significant disability and economic burden with approximately 500,000 carpal tunnel releases performed annually and economic cost estimates in excess of $2 billion per year within the United States alone.^[3] Timely surgical intervention after failure of conservative measures may reduce economic loss and prevent permanent disability and need for reconstructive procedures.^[1]

Both open carpal tunnel release (OCTR) and endoscopic carpal tunnel release (ECTR) are popular techniques for surgical treatment of carpal tunnel syndrome. Although there currently is no consensus regarding the choice of one over the other, rates of ECTR continue to rise. Between 2005 and 2012, 14% of all carpal tunnel releases performed in the Medicare database were done endoscopically, with rates of ECTR growing by 5% annually compared with 0.9% annually for OCTR (P < 0.001).^[4] Recent survey studies of the members of the American Society for Surgery of the Hand have shown as many as 26% to 36% of members using ECTR for most of their cases.^[5,6] Looking at young surgeons specifically, a query of the American Board of Orthopaedic Surgery Part II database revealed an increasing proportion of carpal tunnel releases performed endoscopically, with hand fellowship-trained surgeons performing 4.5 times as many ECTRs as nonhand fellowship-trained surgeons.^[7] In light of the growing popularity of ECTR, it is becoming increasingly important for surgeons to understand the technical aspects and outcomes of this technique.

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Abstract and Introduction
Surgical Technique
Variations in Contemporary Systems
Concerns
Endoscopic Versus Open Carpal Tunnel Release
Summary
References

Table 1. Summary of Recent Meta-analysis Results Comparing ECTR With OCTR
Author(s)	Chen et al¹⁸	Sayegh et al²¹	Vasiliadis et al²²	Li et al¹⁷
Year	2014	2015	2015	2020
No. of studies	15	21	27	28
Symptom relief	Pain relief by VAS at < 3 mo: RR = 1.13 (U) [0.98, 1.31]; P = 0.10; n = 470 Pain relief by VAS at > 3 mo: RR 1.02 (U) [0.92, 1.14]; P = 0.71; n = 340	BCTQ-S: SMD = 0.04 (O) [−0.11, 0.18]; P = 0.64; n = 715 BCTQ-F: SMD = −0.06 (E) [−0.30, 0.19]; P = 0.65; n = 592 VAS: MD = −0.13 (E) [−0.55, 0.28]; P = 0.53; n = 455	Recurrence: OR = 1.02 (O) [0.55, 1.90]; P > 0.05; n = 1,684	BCTQ-S at 1 yr: MD = 0.15 (E) [−0.04, 0.35]; P = 0.13; n = 592 BCTQ-F at 1 yr: MD = 0.17 (E) [−0.02, 0.36]; P = 0.08; n = 592
Grip strength	At 3 mo: MD = 1.96 kg (E) [−0.47, 4.38]; P = 0.11; n = 297	All time points: MD = 3.03 kg (E) [0.08, 6]; P = 0.04; n = 1,196 Long term (>6 mo): MD = 0.90 kg (E) [−1.47, 3.27]; P = 0.46; n = 571	Not analyzed	At 3 mo: MD = 1.99 kg (O) [−0.43, 4.42]; P = 0.11; n = 297
Key pinch strength	At 3 mo: MD = 0.83 kg (E) [0.31, 1.35]; P = 0.002; n = 297	All time points: MD = 0.77 kg (E) [0.33, 1]; P = 0.001; n = 290 Long term (>6 mo): MD = 0.37 kg (E) [−0.09, 0.84]; P = 0.12; n = 614	Not analyzed	At 3 mo: MD = 0.79 kg (E) [0.27, 1.32]; P = 0.003; n = 297
Sensation	Paresthesia relief by Semmes-Weinstein at < 3 mo: RR = 0.94 (U) [0.85, 1.04]; P = 0.21; n = 552 Paresthesia relief by Semmes-Weinstein at > 3 mo: RR = 1.07 (U) [0.98, 1.17]; P = 0.12; n = 296	Semmes-Weinstein: MD = −0.02 (O) [−0.16, 0.12]; P = 0.76; n = 589 Static two-point discrimination: MD = 0.04 mm (E) [−0.35, 0.43]; P = 0.84; n = 579 Static two-point sensory threshold: MD = 0.13 mm (E) [−0.67, 0.94]; P = 0.75; n = 143	Not analyzed	Semmes-Weinstein at 3 mo: MD = 0.06 (O) [−0.09, 0.21]; P = 0.43; n = 297 Two-point discrimination at 1 yr: MD = −0.16 mm (E) [−0.45, 0.12]; P = 0.26; n = 402
Return to work	MD = −8.21 d (E) [−9.79, −6.63]; P < 0.001; n = 362	MD = −8.73 d (E) [−12.82, −4.65]; P < 0.001; n = 1,234	MD = −9.56 d (E) [−12.51, −.60]; P < 0.05; n = 1,115	MD = −7.25 d (E) [−14.31, −0.19]; P = 0.04; n = 357
Complications	Permanent nerve injury: RR = 0.31 (E) [0.05, 1.91]; P = 0.21; n = 302 Transient neurapraxia: RR = 2.90 (O) [1.14, 7.36]; P = 0.02; n = 746 Wound/scar complications: RR = 0.34 (E) [0.12, 0.96]; P = 0.04; n = 733 CRPS: RR = 0.35 (E) [0.10, 1.24]; P = 0.10; n = 396 Revision surgery: RR = 1.18 (O) [0.53, 2.63]; P = 0.68; n = 1,031	Nerve injury (all): RR = 2.84 (O) [1.08, 7.46]; P = 0.03; n = 1,573 Scar tenderness: RR = 0.53 (E) [0.35, 0.82]; P = 0.005; n = 581) Pillar pain: RR = 0.93 (E) [0.45, 2]; P = 0.85; n = 449 Revision surgery: RR = 1.77 (O) [0.64, 5]; P = 0.27; n = 957	All complications: OR = 0.82 (E) [0.52, 1.51]; P > 0.05; n = 2,442 Major complications: OR = 1.00 (NA) [0.44, 2.27; P > 0.05; n = 2,565 Minor complications: OR = 0.50 (E) [0.31, 0.82]; P < 0.05; n = 2,442 Transient neurapraxia: OR = 2.42 (O) [1.22, 4.80]; P < 0.05; n = 2,182 Wound/scar complications OR = 0.24 (E) [0.15, 0.40]; P < 0.05; n = 1,943 Revision surgery: OR = 1.36 (O) [0.61, 3.00]; P > 0.05; n = 1,596	All complications: OR = 1.06 (O) [0.69, 1.64]; P = 0.78; n = 2,320 Permanent nerve injury: OR = 1.93 (O) [0.58, 6.40]; P = 0.28; n = 2,320 Transient neurapraxia: OR = 4.87 (O) [1.37, 17.25]; P = 0.01; n = 2,320 Wound/scar complications: OR = 0.20 (E) [0.07, 0.59]; P = 0.004; n = 2,320
Surgical time	Not analyzed	MD = −5 min (E) [−9, 0]; P = 0.03; n = 695	Not analyzed	MD = −5.81 min (E) [−17.85, 6.23]; P = 0.34; n = 261
Satisfaction rate	Not analyzed	Omitted due to lack of validated measure	Not analyzed	Scale from 0 to 100: MD = 3.13 (E) [1.43, 4.82]; P < 0.001; n = 303

BCTQ-F = BCTQ functional status score, CRPS = complex regional pain syndrome, ECTR = endoscopic carpal tunnel release, MD = mean difference, NA = not analyzed, OCTR = open carpal tunnel release, OR = odds ratio, RR = relative risk, SMD = standardized mean difference, VAS = Visual Analogue Scale
Meta-analyses from 2014 to present analyzing 15 or more randomized trials were included. Results presented as [95% confidence ratio lower bound, upper bound]; P value; number of samples. Statistically significant results (P < 0.05) presented in bold. (E) = favors endoscopic carpal tunnel release (ECTR) (ie, greater relief of symptoms, lower rate/risk of complications, faster return to work, and faster procedure). (O) = favors open carpal tunnel release (OCTR). (NA) = does not favor either ECTR or OCTR. (U) = unclear from study description whether ECTR or OCTR is favored. BCTQ-S = Boston Carpal Tunnel Questionnaire (BCTQ) symptom severity score.