Abstract
Objective:
Endoscopic carpal tunnel release has become increasingly popular and has shown the advantage of early recovery of hand function with minimal morbidity. In this systematic review, we aimed to summarize the currently available data and describe the reported advantages and disadvantages of endoscopic carpal tunnel surgery for treating carpal tunnel syndrome.
Methods:
In this study, we followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, which is a set of reporting requirements for systematic reviews and meta-analyses. The search strategy with MeSH terms was “MeSH (carpal tunnel syndrome) AND (endoscopic)” Filters: in the last 5 years, English—on February 27th, 2022. A total of 131 articles fulfilled the first screening criteria. A detailed analysis of those articles identified 39 that matched the criteria, of which 14 were considered appropriate for this analysis after applying the complete inclusion and exclusion criteria.
Results:
A total of 14 studies met the eligibility criteria. Analysis of those studies found that all types of portals in endoscopic carpal tunnel release reduced postoperative pain at a short-term follow-up. There was no evidence to suggest the superiority of the single- or two-portal techniques in terms of outcomes. In terms of pain relief, symptom resolution, patient satisfaction, duration to return to work, and adverse events, this early use of endoscopic carpal tunnel release produced satisfactory outcomes. Further studies comparing the number of portals are needed.
Conclusion:
Endoscopic carpal tunnel surgery for treating carpal tunnel syndrome is effective and both single- and dual-portal techniques provide advantages in terms of early recovery and minimal morbidity.
Introduction
One of the most prevalent musculoskeletal diseases of the hand and wrist is carpal tunnel syndrome (CTS).1,2 Most evidence supports splinting and medication as first-line therapies.2–4 However, surgical treatment, independent of approach, has proven to be superior to nonoperative treatment. 5
Open carpal tunnel release (OCTR) remains the gold standard procedure for CTS and has evolved into a mini-open procedure with the development of new devices. 6 There is no clear rule about whether the open approach or the closed approach is better. Although the choice between the endoscopic and the open approach is still controversial, endoscopic carpal tunnel release has recently become increasingly popular in hand surgery practice due to the advantages of early recovery of hand function and minimal morbidity.7–11 However, endoscopic carpal tunnel release has its own imitations. 6 Since their introduction in the late 1980s, endoscopic techniques have evolved significantly with many different techniques using either a single portal or two portals including the Chow technique and the Agee and Brown technique. 12
However, these endoscopic techniques have been associated with a higher risk of nerve injury (neuropraxia) and tendon injury, and depend on the surgeon’s experience. 13 However, there have been no systematic reviews specifically of endoscopic carpal tunnel release.
This study aimed to analyze the currently available data and summarize the reported advantages and disadvantages of only endoscopic carpal tunnel surgery for treating CTS, which has two major goals. The primary goal is to focus on the clinical and functional outcomes after surgery. The secondary goal is additional outcomes, including postoperative imaging and laboratory investigation, to help surgeons choose the appropriate technique for patients in their practice.
Methods
Literature search strategy
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 14 criteria (Figure 1) were followed in conducting this systematic review. A literature search was performed using the PubMed search engine to collect articles published in PubMed between 2017 and 2022 using the MeSH terms. Only the 5 most recent years of publication were included to focus on the most recent ideas. The search strategy for inclusion in this study was “MeSH (carpal tunnel syndrome) AND (endoscopic)” Filters: in the last 5 years, English—on February 27th, 2022. Additional manual checks of the reference lists were also accomplished. Only articles written in English were considered for inclusion. This systematic review was registered by PROSPERO International Prospective Register of Ongoing Systematic Reviews (Registration number: CRD42023409964). However, ethical and consent approval is not applicable.
Systematic reviews and meta-analyses (PRISMA) flow diagram of the study.
Inclusion and exclusion criteria
Randomized controlled trials (RCTs) and observational cohort studies were included in this systematic review. There were no restrictions on the type of study, for example, retrospective or prospective; however, all studies had to be published in English. The search did not include case reports, case studies, or technical notes. All of the identified articles’ titles and abstracts were evaluated and reviewed. All articles and journals were thoroughly studied, and essential details were recorded.
Data extraction
The following data on the studies were recorded: (1) author and year of publication, (2) type of study design 15 and the country in which the surgery was conducted, (3) sample size and mean age of patients (mean ± SD), (4) diagnostic tools used, (5) type of anesthetic and administration technique, (6) endoscopic technique and surgical approach, (7) final outcome, (8) complications, and (9) follow-up period.
Assessment of risk of bias of this systematic review
RevMan (Review Manager, Version 5.4, Cochrane Collaboration, 2020), the Cochrane Collaboration tools for assessing the risk of bias in randomized trials, was used to determine the risk of bias for individual RCTs. The evaluation included selection bias, performance bias, attrition bias, bias in detection, and bias in reporting, each of which was classified as high risk, low risk, or uncertain risk. Two investigators rated the included studies’ levels of bias separately before comparing their results. Consensus-based decisions were made in cases of disagreement, and a third author’s assessment was sought if necessary. A third reviewer also resolved any remaining disagreements regarding evaluation of the retrieved data.
The description of the surgical techniques
As an illustration of the single-portal approach (Agee technique), a video endoscope, a pistol-grip handpiece, and an endoscope-blade assembly that was inserted into the carpal tunnel comprised the system. There was a trigger mechanism incorporated into the pistol-grip hand piece. Through a window located near the assembly’s tip, the bottom of the transverse carpal ligament (TCL) could be seen using an endoscope. A 3-cm incision in the wrist flexor crease was created to install the entire device. A trigger-activated mechanism allowed a triangular blade to engage and elevate 3.5 mm above the surface of the assembly. The blade engaged, cutting the TCL, and the complete unit was extracted. 16
In contrast, the proximal portal is formed using the dual-portal approach (Chow technique) by drawing a line 1–1.5 cm radially to the proximal pole of the pisiform bone. 0.5 cm in front of the end of the first line is where the second line is indicated. To represent the entry portal, a third line is drawn about 1 cm radially from the end of the second line. A trocar is inserted, the wrist is stretched, and a specific hand frame holds it in place. A second incision is made 1 cm in front of a line that cuts through the angle produced by the third web space and the distal border of the fully abducted thumb. The trocar, which has a slotted end that sits directly below the TCL, is entered with the endoscope inserted proximally. The distal end is chopped proximally with a probe (forward-facing) knife. 17
Results
A total of 131 articles found in the PubMed database fulfilled the first screening criteria. A detailed analysis discovered 39 articles that matched the criteria of which 14 were considered qualified for inclusion in this analysis after applying the complete inclusion and exclusion criteria (Figure 1). All articles reported on an incidence of endoscopic carpal tunnel surgery with either a single-portal technique or a dual-portal technique. All the studies of carpal tunnel surgery included the diagnosis of carpal tunnel disease and a description of the treatment with endoscopic surgery.
Demographic data analysis
Data on the studies, including author, year of publication, country in which the surgery was conducted, study design, average age of the patients, sample size, gender ratio, diagnostic tools, anesthetic technique, endoscopic technique, surgical approach (single-portal or dual-portal technique), clinical outcome parameter measurement score, complications, and average time of follow-up were reviewed and analyzed (Table 1).
Demographic data.
Risk of bias analysis
A summary of the non-RCT risk of bias is shown in Table 2. Three studies had a high risk of bias in the selection of participants, of which two were at high risk of measurement of exposure and one had a high risk of confounding variables. All studies had a low risk of performance bias for blinding of outcome assessment, incomplete outcome data, and selection outcome reporting. Most of the RCT risk of bias included studies with a lower risk of reporting bias (Table 3).
The non-RCT risk of bias in this systematic review.
The RCT risk of bias in this systematic review.
Study design and publication information
In this review, we found blinded RCT studies, prospective studies, and retrospective studies. Two studies were RCT studies by Kempton et al. 18 and Truelove et al. 19 . Seven studies were prospective studies, the most prevalent research design, including studies by Degeorge et al., 20 Li et al., 21 Trung et al., 22 Grandizio et al., 23 Ng et al.,24,25 and Rooij et al. 26 Only five retrospective studies were identified, by Satteson et al., 27 Hein et al., 28 Liu and Wu, 29 Wellington et al., 30 and Tarfusser et al. 31
Nationality
The number of publications on endoscopic carpal tunnel surgery increased between 2015 and 2021 as the trend toward this surgical technique grew. The studies included six articles from the United States, two articles each from the China and Hong Kong, and one article each from France, Vietnam, the Netherlands, and Italy.
Samples size
A 2018 retrospective study conducted in the United States between 2011 and 2016 by Satteson et al. had the largest sample size with 522 patients and 897 wrists using endoscopic surgery, whereas a retrospective review by Liu and Wu 29 in China had the smallest sample size of eight patients. A prospective study in Vietnam by Trung et al. 22 had the largest sample size of 150 patients. Two RCT articles reported sample sizes of 30 patients (Kempton et al. 18 ) and 44 patients (Truelove et al. 19 ), both from the United States.
Gender ratio and average age
In 14 studies, the average age was 53.6 years (range 29–60.5 years). The maximum average age, 60.5 years, was in the studies by Degeorge et al. 20 and Tarfusser et al., 31 while the minimum average age was 29 years in the study by Kempton et al., 18 which studied surgical learning modules. Twelve studies had a predominance of females over males. Only Kempton et al. 18 included more males than females, and one study by Wellington et al. 30 did not demonstrate the sex aspect.
Diagnostic tools and parameter scores
Eleven studies included information on the tools used for diagnosis, including clinical and neurological evaluation Liu and Wu, 29 electrodiagnostic study results (EMG), and NCS. The parameters varied depending on the objectives of the study. Pain outcome measurement included the 11-point pain scale of the Boston Carpal Tunnel Questionnaire (BCTQ), 32 and a six-point CTS-6 score. 33 Clinical and functional outcomes included the visual analog scale (VAS),34,35 Quick Disabilities of the Arm, Shoulder, and Hand (DASH) score, 36 Activities of Daily Living (ADL) scale, 37 the DASH score, 38 pinch and grip strength,39,40 two-point discrimination,41,42 and the number of days until self-reliance. 26 Secondary outcomes included imaging and postoperative investigations: motor NCSs, sensory nerve conduction velocities (SNCV) and sensory nerve action potential (SNAPS), cross-sectional area (CSA), edema length (EL), anteroposterior diameter of median nerve (D), as well as median nerve CSA, width, height, TCL width, and anteroposterior dimension of the carpal tunnel. Some studies evaluated surgical timing using a five-point scoring system based on a written multiple-choice test, for example, Wellington et al. 30 and Kempton et al. 18
Anesthetic and endoscopic technique
Anesthetic and endoscopic technique of the 12 publications that reported on anesthetic aspects, most reported the use of regional or local anesthesia. A monitored anesthesia care technique was added by Hein et al., 28 while Tarfusser et al. 31 used only the wide-awake, local anesthesia, no tourniquet (WALANT) technique in all samples. Wellington et al. 30 compared the outcome of monitored anesthesia care with tourniquet, (MT) 43 local anesthesia with tourniquet (LT), and WALANT. That study reported that WALANT was favored over MT and LT for average operating room time.
Regarding endoscopic techniques, nine studies used a single-portal endoscopic technique with different approaches. Degeorge et al., 20 Trung et al., 22 and Grandizio et al. 23 demonstrated the Agee technique in a single-portal endoscopic technique which incised the wrist crease from proximal to distal and then inserted a clear plastic cannula with an angled endoscope. Van Rooij et al. 26 following Fechner et al. (2013) 44 used a single-portal technique, claiming that it will can better prevent accidental injury to the median nerve . Liu and Wu 29 used a new technique using a plastic shield created from a standard syringe that offers a 360° view of the carpal tunnel and provides protection for the median nerve in single-portal endoscopic techniques. Another single-portal method using a transretinacular technique was demonstrated in a study by Tarfusser et al. 31
A two-portal endoscope method was used by Li et al. 21 via the Chow technique, a transbursal approach, while both of Ng et al.’s24,25 studies used the portal to divide the flexor retinaculum with a retrograde hook knife. Grandizio et al. 23 and Wellington et al. 30 did not report the number of endoscopic portals.
Final outcome and complications
This systematic review classified surgical outcomes into two groups: primary and secondary outcomes (Table 4). The primary outcome was determined by an evaluation of the clinical and functional results postoperatively, while the secondary outcome included the imaging parameter and other factors that could not be classified as primary outcomes.
Surgical outcomes and complications.
We found that most of the endoscopic studies reported satisfaction with the primary outcome. Studies using the Agee technique with a single-portal endoscopic procedure included Degeorge et al. 20 which reported that 97% of patients were satisfied or very satisfied with the outcome and that mean pain had statistically significantly decreased. Trung et al. 22 reported that 98% of hands showed improvement in numbness, paresthesia, and pain reduction at the 1-month follow-up, and 92% had full recovery of muscle function at the 6-month follow-up. Grandizio et al. 23 claimed that all operations resulted in complete symptom resolution postoperatively. Those using the Agee technique did not report any complications, although a single case of superficial infection of the operated site (1.7% of patients) was reported by Degeorge et al. 20
Another single-portal technique used in the study by van Rooij et al. 26 which employed the technique described by Fechner et al. (2013) 44 and stated that postoperative functional status increased significantly on a daily basis, and that the mean BCTQ score decreased gradually from intense difficulty to little difficulty in daily tasks over a period of 7 days. Tarfusser et al. 31 using another single-portal via transretinacular technique stated that all patients reported rapid recovery, pain subsidence, and return to daily activity within a few days, although one patient did not experience measurable improvement of grip strength or sensory function, but only disappearance of pain and discomfort at 2 weeks after surgery. Liu and Wu 29 used a new plastic shield portal technique and reported that DASH, BCTQ, and VAS were statistically significantly decreased compared to preoperation.
Two studies of the single-portal technique did not report details of the specific technique or the approach used in the surgery. Satteson et al. 27 reported a significant difference only in incidence of neuropraxia, with higher rates occurring in the mild neuropraxia group. Hein et al., 28 using a MicroAire single-portal smart release set, reported that their patients used narcotic pain medication for only 2 days following the operation and returned to ADL in an average of 5 days. The rate of use of narcotic pain medications was higher in females than in males. One superficial infection was treated with oral antibiotics and one patient had persistent CTS symptoms requiring return to the operating room. An anesthetic comparison study by Truelove et al. 19 stated that patients in the IV acetaminophen group reported less pain than both those in the IV ketorolac group (p < 0.001) and those in the combination group (p = 0.03), but there was no difference in mean pain scores between the IV acetaminophen and placebo groups (p = 0.99). The authors suggested that further study was needed to increase the power of their results.
Two-portal endoscope technique studies by Ng et al.24,25 which used the portal to divide the flexor retinaculum with a retrograde hook knife showed mean clinical improvement scores of 3.49 ± 0.56 and 2.2 ± 0.7 at 12 months. Grandizio et al. 23 reported on changes in median nerve and carpal tunnel morphology that occurred immediately after surgery and which remain unchanged at the midterm follow-up. All patients reported complete symptom resolution postoperatively without complications.
In regard to the secondary outcomes, Kempton et al. 18 reported that the surgical module for doctors reported an average operation performance score of 96%. Li et al. 21 NCSs after two-portal ECTS using Chow’s technique reported that neuroanatomical parameters gradually improved after ECTR surgery and that the best time for ultrasound follow-up is at the 3-month postoperative time point for patients who do not show clinical improvement.
Wellington et al.’s 30 study of surgical timing with different anesthetic techniques did not report the surgical technique used, but favored WALANT over MT and LT for average operating room time (20 min, SD: 3; 32 min, SD: 6; and 23 min, SD: 3, respectively).
The study by Grandizio et al. 23 stated that the median nerve CSA and the anterioposterior dimension of the carpal tunnel at the level of the hamate increased immediately after surgery using three portals and that those changes were maintained for 6 years postoperatively.
Discussion
The most frequent individual’s awareness of the hands is CTS. Clinical relevance in the general population is 3.8%. 45 Patients with CTS who have sustained numbness, discomfort for longer than 6 months, or who did not receive sufficient conservative therapy require surgical treatment. 46 Surgery is performed on between 31% and 40% of CTS patients, a noteworthy percentage. If the patient has significant compression and thenar muscle atrophy, urgent decompression is required to enable a potential full recovery. Prior to surgery, patients should be informed of the nature of the proposed treatment plan. Advanced surgical procedures have seen ongoing improvement in terms of minimally invasive surgery. There has been a significant paradigm shift from traditional big-open surgery to minimally invasive surgery such as ECTR, resulting in improved patient benefits and quicker recovery. ECTR is one of the advances, with the small incision allowing for faster recovery and earlier return to normal activity. 11
For this analysis, 14 studies conducted in the past 5 years met the inclusion criteria. The endoscopic techniques used can be classified into two main types: single portal and dual portal. Within each of these two main types, there are many different approaches. Results indicate that with all types of portals, ECTR decreased postoperative discomfort during close follow-up. Among the studies that satisfied the inclusion requirements, six studies investigated imaging parameters at short-term follow-up, whereas eight studies analyzed pain and function as a primary endpoint. The majority of studies used the BCTQ for evaluation, and they found short-term pain reduction after ECTR at intervals of between 1 day and 2 weeks (van Rooij et al. 26 ; Tarfusser et al. 31 ; Liu and Wu 29 ; Trung et al. 22 ; Degeorge et al. 20 ). Several studies additionally reported imaging parameters at long-term follow-up ranging from 2 weeks to 6 years (Grandizio et al. 23 ; Ng et al.24,25). Following ECTR, no study reported inferior pain outcomes.
Selecting the right patients is crucial to a successful outcome. Candidates should only be patients with classic CTS. Patients with recognized anomalies of the anatomy, ganglion or synovial cysts, neuromas, a fracture history, septic or inflammatory tenosynovitis, and CTR failures in the past, among other conditions, are contraindicated. Large, bulky hands can be challenging to work on technically. 47
Clinical patients’ outcome evaluations following all endoscopic surgeries showed impressive outcomes, but, single-portal operations were reported to have had more complications due to superficial infection than dual portals. However, several studies did not provide information on the complications.
Although there is no proof that one over two-portal approaches produce better results, with a single-portal system, the blade and camera are combined into a single device. Instead of a little off-center image, the severed ligament may be directly seen, thanks to that combination. However, the two-portal system allows for direct viewing when rasping or probing, which may increase safety and is not feasible with the single-portal method. The single or uniportal technique has been recommended because of the lack of persistent pain and dysesthesia in the palmar area attributable to the second incision performed in the dual-portal technique, but the limited visual information is a disadvantage of the single-portal technique. Ulnar neurapraxia and damage to sensible nerves have been reported with the single-portal technique but are very rarely reported with the dual-portal technique.
Brown’s two-portal technique was evaluated by Piccirilli et al., who concluded that when the right steps are rigorously followed, it looks to be a safe and reliable ECTR technique. The partial release of the TCL in three cases and one incidence of moderate neuropraxia indicate that there is a learning curve with this treatment. However, we discovered that the technique was simple to understand and apply. 48
For the limitations of this systematic review, the number of ECTR randomized and non-randomized controlled trials was still limited studies. This study was a detailed analysis of those 39 articles identified from MEDLINE (Scopus database) that matched the criteria, of which 14 were considered appropriate for this analysis because they were not compared with OCTR. However, our next research would compare ECTR and OCTR in a systematic review and meta-analysis of future clinical studies. Furthermore, the purpose of the study of Truelove et al. 19 was to determine if perioperative administration of intravenous NSAIDs decreases postoperative pain and opioid consumption after ECTR, which does not completely match the aim of the study. However, Truelove et al. still provides some essential information about the ECTR, especially, in postoperative pain management. Another limitation issue is that only the 5 most recent years of publication, from 2017 to 2022, were included to focus on the most recent ideas. However, this could limit some beneficial information in the past.
In conclusion, CTS is a common condition that is readily treated and healed. Conventional or mini-open surgery could be the future standard for CTS treatment, but in moderate to severe situations, surgery is required. It is crucial to release the transverse carpal ligament under the arthroscope the entire time, regardless of whether there are one or two portals. To guarantee safety, it is advised that the operation be carried out while always being visible. One of the most cutting-edge minimally invasive carpal tunnel release procedures, the ECTR with single- and two-portal approaches, has demonstrated good results in terms of lowering complications and ensuring a safe and successful operation. 9
Conclusions
Overall, literature from randomized and non-RCTs demonstrates that endoscopic surgery is the minimally invasive surgery and that ECTR technique promotes faster recovery of return to work, high satisfaction, improved hand grip strengths, and fewer scar-related problems. This systematic review implies that ECTR can be used effectively to treat patients with CTS. Both the single- and two-portal approaches to endoscopic surgery for carpal tunnel release are employed, and good clinical results and patient satisfaction are obtained more rapidly. Both techniques are safe, effective, and optional minimally invasive treatments for CTS.
Supplemental Material
sj-doc-1-smo-10.1177_20503121231177111 – Supplemental material for Endoscopic carpal surgery in carpal tunnel syndrome: A systematic review
Supplemental material, sj-doc-1-smo-10.1177_20503121231177111 for Endoscopic carpal surgery in carpal tunnel syndrome: A systematic review by Wongthawat Liawrungrueang, Sunton Wongsiri and Peem Sarasombath in SAGE Open Medicine
Footnotes
Acknowledgements
All authors would like to express their sincere thanks to Dr. G. Lamar Robert, PhD, and Associate Professor. Dr. Chongchit Sripun Robert, PhD, for editing the English article.
Author contribution
All authors contributed to the study’s conception and design. Material preparation, data collection, and analysis were performed by WL, SW, and PS. The first draft of the article was written by WL and PS. All authors commented on previous versions of the article. All authors read and approved the final article.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Research registration number
This systematic review was registered by PROSPERO International Prospective Register of Ongoing Systematic Reviews (Registration number: CRD42023409964).
Availability of data and material
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Supplemental material
Supplemental material for this article is available online.
References
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