Endoscopic carpal tunnel release: results with special consideration to possible complications

Update on surgical procedures for carpal tunnel syndrome: What is the current evidence and practice? What are the future research directions?

Carpal tunnel syndrome (CTS) is a multifactorial compression neuropathy. It is reported to be very common and rising globally. CTS’s treatment varies from conservative measures to surgical treatments. Surgery has shown to be an effective method for more severe cases. However few unclear aspects and room for further research and improvements still remains. We performed a narrative literature review on the most up to date progress and innovation in terms of surgical treatments for CTS. The simple algorithm of leaving the choice of the surgical method to surgeons’ preference and experience (together with consideration of patients’ related factors) seem to be the best available option, which is supported by the most recent metanalysis and systematic reviews. We suggest that surgeons (unless in presence of precise indications towards endoscopic release) should tend to perform a minimally invasive open approach release, favoring the advantage of a better neurovascular structures visualization (and a consequent higher chance to perform a complete release with long term relief of symptoms) instead of favoring an early reduction (in the first postoperative days) of immobilization and pain. Research towards a universally accepted standardization should be aimed for by the researchers, who have failed to date to sufficiently limit bias and limitations.

Neurologic complications in common wrist and hand surgical procedures

Nerve dysfunction after upper extremity orthopedic surgery is a recognized complication, and may result from a variety of different causes. Hand and wrist surgery require incisions and retraction that necessarily border on small peripheral nerves, which may be difficult to identify and protect with absolute certainty. This article reviews the rates and ranges of reported nerve dysfunction with respect to common surgical interventions for the distal upper extremity, including wrist arthroplasty, wrist arthrodesis, wrist arthroscopy, distal radius open reduction and internal fixation, carpal tunnel release, and thumb carpometacarpal surgery. A relatively large range of neurologic complications is reported, however many of the studies cited involve relatively small numbers of patients, and only rarely are neurologic complications included as primary outcome measures. Knowledge of these neurologic outcomes should help the surgeon to better counsel patients with regard to perioperative risk, as well as provide insight into workup and management of any adverse neurologic outcomes that may arise.

The Potential Benefit of Intracarpal Pressure Measurement in Endoscopic Carpal Tunnel Syndrome Surgery – An Analysis of EMG Findings and Pressure Values

Endoscopic carpal tunnel syndrome surgery is a modern minimally invasive method of carpal tunnel decompression. However, the method does also have its critics, who emphasize that there is an increased rate of complications in comparison to open procedures. To further improve and optimize results of endoscopic surgery we used an intracarpal pressure sensor to verify the effect of carpal tunnel decompression. The endoscopic single portal approach was used in all cases. Median nerve conduction studies were performed prior to and 3 months after surgery. Two groups, those with pressure studies and those without, were then compared according to several EMG parameters such as: median nerve distal motor latency, amplitude of motor response, sensory nerve conduction velocity to the index finger, and amplitude of sensory nerve action potential. In both groups, we observed similarly significant improvements in all conduction parameters, except the amplitude of motor response, which did not change in either group, i.e. no difference in postoperative EMG between the two groups was observed. Despite this fact, intracarpal pressure measurement is still useful in localising the point in which the median nerve is compressed and provides valuable functional information on the level decompression achieved.

Endoscopic and Open Release Similarly Safe for the Treatment of Carpal Tunnel Syndrome. A Systematic Review and Meta-Analysis

BACKGROUND

The Endoscopic Release of Carpal Tunnel Syndrome (ECTR) is a minimal invasive approach for the treatment of Carpal Tunnel Syndrome. There is scepticism regarding the safety of this technique, based on the assumption that this is a rather "blind" procedure and on the high number of severe complications that have been reported in the literature.

PURPOSE

To evaluate whether there is evidence supporting a higher risk after ECTR in comparison to the conventional open release.

METHODS

We searched MEDLINE (January 1966 to November 2013), EMBASE (January 1980 to November 2013), the Cochrane Neuromuscular Disease Group Specialized Register (November 2013) and CENTRAL (2013, issue 11 in The Cochrane Library). We hand-searched reference lists of included studies. We included all randomized or quasi-randomized controlled trials (e.g. study using alternation, date of birth, or case record number) that compare any ECTR with any OCTR technique. Safety was assessed by the incidence of major, minor and total number of complications, recurrences, and re-operations.The total time needed before return to work or to return to daily activities was also assessed. We synthesized data using a random-effects meta-analysis in STATA. We conducted a sensitivity analysis for rare events using binomial likelihood. We judged the conclusiveness of meta-analysis calculating the conditional power of meta-analysis.

CONCLUSIONS

ECTR is associated with less time off work or with daily activities. The assessment of major complications, reoperations and recurrence of symptoms does not favor either of the interventions. There is an uncertain advantage of ECTR with respect to total minor complications (more transient paresthesia but fewer skin-related complications). Future studies are unlikely to alter these findings because of the rarity of the outcome. The effect of a learning curve might be responsible for reduced recurrences and reoperations with ECTR in studies that are more recent, although formal statistical analysis failed to provide evidence for such an association.

LEVEL OF EVIDENCE

I.

Endoscopic and Open Release Similarly Safe for the Treatment of Carpal Tunnel Syndrome. A Systematic Review and Meta-Analysis

Background

The Endoscopic Release of Carpal Tunnel Syndrome (ECTR) is a minimal invasive approach for the treatment of Carpal Tunnel Syndrome. There is scepticism regarding the safety of this technique, based on the assumption that this is a rather “blind” procedure and on the high number of severe complications that have been reported in the literature.

Purpose

To evaluate whether there is evidence supporting a higher risk after ECTR in comparison to the conventional open release.

Methods

We searched MEDLINE (January 1966 to November 2013), EMBASE (January 1980 to November 2013), the Cochrane Neuromuscular Disease Group Specialized Register (November 2013) and CENTRAL (2013, issue 11 in The Cochrane Library). We hand-searched reference lists of included studies. We included all randomized or quasi-randomized controlled trials (e.g. study using alternation, date of birth, or case record number) that compare any ECTR with any OCTR technique. Safety was assessed by the incidence of major, minor and total number of complications, recurrences, and re-operations.The total time needed before return to work or to return to daily activities was also assessed. We synthesized data using a random-effects meta-analysis in STATA. We conducted a sensitivity analysis for rare events using binomial likelihood. We judged the conclusiveness of meta-analysis calculating the conditional power of meta-analysis.

Conclusions

ECTR is associated with less time off work or with daily activities. The assessment of major complications, reoperations and recurrence of symptoms does not favor either of the interventions. There is an uncertain advantage of ECTR with respect to total minor complications (more transient paresthesia but fewer skin-related complications). Future studies are unlikely to alter these findings because of the rarity of the outcome. The effect of a learning curve might be responsible for reduced recurrences and reoperations with ECTR in studies that are more recent, although formal statistical analysis failed to provide evidence for such an association. Level of evidence: I.

A cadaveric and preliminary clinical study of ultrasonographically assisted percutaneous carpal tunnel release

The aim of this study was to assess the effectiveness and safety profile of a new technique for ultrasonographically assisted percutaneous carpal tunnel release. Experiments were performed on 40 hands in 20 cadavers. We first performed a detailed ultrasonographic examination and correlation study that included surgical dissection of the transverse carpal ligament, the related neurovascular structures and the bony landmarks of the radiocarpal, midcarpal and carpometacarpal joints of the right hand. We then used the measurements we made for percutaneous carpal tunnel release of the transverse carpal ligament using intra-operative ultrasonography for guidance and a hook knife on the left-hand side. The completeness of the release and the potential risks of injury to the flexor tendon and neurovascular bundles were examined. Using real-time intra-operative ultrasonographic monitoring to clearly delineate these targets, we were able to percutaneously release the transverse carpal ligament completely in 18 (90%) of the 20 hands and partially release it in 2 without injuring any neurovascular bundles. We then performed the procedure on 91 consecutive cases of carpal tunnel syndrome and found that the sensory disturbances disappeared in 100% patients 12 mo post-operatively; only 2 hands were graded as unsatisfactory. There were no intra- or post-operative complications. Based on the results from the cadaveric studies and our successful preliminary clinical outcomes, we conclude that this method is tolerable and that its clinical application can be encouraged.

Carpal tunnel pressure measurement during two-portal endoscopic carpal tunnel release

BACKGROUND

Although there remain concerns of median nerve damage during endoscopic carpal tunnel release for carpal tunnel syndrome, carpal tunnel pressure variations during Chow's two-portal technique have not been well investigated.

METHODS

We performed a modified two-portal endoscopic carpal tunnel release on 30 patients by inserting a catheter pressure transducer into the carpal tunnel for continuous pressure measurement during the procedure. Grip and pinch strengths, Semmes-Weinstein monofilament test, and nerve conduction studies were examined preoperatively and at postoperative 1, 3, and 6 months. Numbness and the Disabilities of the Arm, Shoulder and Hand score were also evaluated pre and postoperatively.

FINDINGS

Subjective symptoms and nerve conduction study findings improved uneventfully. The pressure was always observed to be maximum pressure immediately before the cannula was withdrawn from the exit portal, and carpal tunnel pressure >300 mm Hg was recorded in most of the patients.

INTERPRETATION

A transient increase in the carpal tunnel pressure occurred in all the patients; however, it did not correlate with their clinical outcome or with increased risk of peri-operative complications. Since time-pressure threshold of the median nerve during endoscopic carpal tunnel release is still unknown, our results did not guarantee its safety.

Bilateral atypical muscles causing acute bilateral carpal tunnel syndrome in recreational climber

The occurrence of anomalous muscles in the hand is rare, and therefore the clinician frequently does not account for their existence when reaching the diagnosis and concluding the cause of carpal tunnel syndrome. This case report describes the highly unusual case of the occurrence of bilateral flexor digitorum superficialis muscles in a recreational climber who developed CTS following his intensive training schedule.

An ultrasonographic and anatomical study of carpal tunnel, with special emphasis on the safe zones in percutaneous release

We examined 40 wrists of 12 embalmed and eight fresh cadavers and defined the relative position of the flexor retinaculum to the neurovascular structure, ultrasonographic markers and safe zones by ultrasonography and anatomical dissection. Both longitudinal and transverse ultrasonographic sections clearly depicted the flexor retinaculum, neurovascular bundles, median nerve, flexor tendons and bony boundaries of the underlying joints. Topographic measurement showed [i] good correlation between the actual extent of the flexor retinaculum and the ultrasonographically determined distance between bony landmarks in all hands, and [ii] the widths and lengths of well-defined safe zones. A comparison study confirmed the accuracy of ultrasonography. We conclude that these ultrasonographic landmarks can locate the flexor retinaculum and facilitate safe and complete carpal tunnel release with open or minimally invasive techniques.

Endoscopic versus open carpal tunnel release: A short-term comparative study

OBJECTIVE

To compare the results of endoscopic carpal tunnel release (CTR) with open CTR in patients with idiopathic Carpal tunnel syndrome (CTS).

MATERIALS AND METHODS

Seventy-one patients with CTS were enrolled in a prospective randomized study from May 2003 to December 2005. All patients had clinical signs or symptoms and electro-diagnostic findings consistent with carpal tunnel syndrome and had not responded to nonoperative management. Sixty-one cases were available for follow-up. Endoscopic CTR was performed in 30 CTS patients and open CTR was performed in 31 wrists (30 patients). Various parameters were evaluated, including each patient's symptom amelioration, complications, operation time, time needed to resume normal lifestyle and the frequency of revision surgery. All the patients were followed up for six months.

RESULTS

During the initial months after surgery, the patients treated with the endoscopic method were better symptomatically and functionally. Local wound problems in terms of scarring or scar tenderness were significantly more pronounced in patients undergoing open CTR compared to patients undergoing endoscopic CTR. Average delay to return to normal activity was appreciably less in group undergoing endoscopic CTR. No significant difference was observed between the endoscopic CTR group and open CTR group in regard to symptom amelioration, electromyographic testing and complications at the end of six months.

CONCLUSION

Short-term results were better with the endoscopic method as there was no scar tenderness. Results at six months were comparable in both groups.

Sonographically Guided Percutaneous Carpal Tunnel Release

Minimally invasive techniques have become the standard of care for multiple procedures. This paper demonstrates both the surgeons' capacity to perform an accurate anatomic evaluation of the hand and forearm (n=10) and the use of this anatomic information to accurately perform sonographically guided, percutaneous carpal tunnel release using a single-portal endoscope without direct or indirect visualization in a cadaver model (n=6). Open dissection was then performed to confirm complete ligament transection and to evaluate the surrounding structures for injury. In all 6 cadavers, the transverse carpal ligament was transected completely without injury to any surrounding structures. With further investigation, this novel technique may offer a less invasive, office-based method for the surgical treatment of carpal tunnel syndrome that may offer patients an expedited recovery.