Postoperative nerve conduction changes after open and endoscopic carpal tunnel release

Intraoperative Conversion From Endoscopic to Open Carpal Tunnel Release: A Systematic Review and Case Series

PURPOSE

The purpose of this study was to assess the incidence, outcomes, and complications associated with conversion from endoscopic carpal tunnel release (ECTR) to open carpal tunnel release (OCTR).

METHODS

A retrospective case review of all patients who underwent ECTR over 4 years by 2 fellowship-trained hand surgeons at a single academic center was performed. We recorded outcomes and the reason for conversion in patients who underwent conversion to an OCTR. Baseline demographics and surgical complications were compared between the 2 groups. A systematic review was performed to define the incidence and reasons for conversion from ECTR to OCTR. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included clinical studies of ECTR from 2000 to 2021.

RESULTS

In the retrospective series, 9 of 892 (1.02%) ECTR cases underwent conversion to an OCTR at the time of the index procedure. One of 9 converted cases had transient neurapraxia involving the recurrent motor branch after surgery compared with 0 cases in the group that underwent ECTR without conversion. Improvements in the visual analog scale for pain and QuickDASH were noted at a mean of 46 weeks after surgery in the group that underwent conversion to OCTR. The systematic review identified an incidence of conversion of 0.62%. The most common reasons for conversion to OCTR in the case series and systematic review were poor visualization due to hypertrophic tenosynovium and aberrant nerve anatomy.

CONCLUSIONS

The overall incidence of intraoperative conversion from ECTR to OCTR during the index procedure was 1.02%, with the most common reasons for conversion being poor visualization due to hypertrophic tenosynovium and aberrant nerve anatomy. Patients who undergo conversion from ECTR to OCTR demonstrate improvements in pain and disability, similar to patients who undergo ECTR without conversion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The Effect of Vitamin D Deficiency Correction on the Outcomes in Women After Carpal Tunnel Release

PURPOSE

Studies suggest that vitamin D supplementation improves myelination and recovery after nerve injuries. The purpose of this study was to evaluate whether correction of vitamin D level leads to better surgical outcomes in women with both carpal tunnel syndrome (CTS) and vitamin D deficiency.

METHODS

We retrospectively reviewed 84 vitamin D-deficient women with CTS who underwent carpal tunnel release and then received daily vitamin D supplementation of 1,000 IU vitamin D for 6 months. We also reviewed 35 control patients who were vitamin D-nondeficient at baseline and thus did not receive the supplementation. At baseline and 6 months after surgery, we measured serum vitamin D levels, the Disabilities of the Arm, Shoulder, and Hand (DASH) score, motor conduction velocity, and grip and pinch strengths. We compared the outcomes of CTS related to vitamin D levels. We also correlated baseline and follow-up vitamin D levels with the assessed parameters.

RESULTS

At 6 months, 59 patients became vitamin D-nondeficient (≥ 20 ng/mL) and 25 were still vitamin D-deficient (< 20 ng/mL). Patients who became vitamin D-nondeficient had subtle but better DASH scores than patients who were still vitamin D-deficient or the control patients. Vitamin D levels at 6 months were found to have significant correlation with the DASH score at 6 months. Vitamin D levels at 6 months did not have significant correlation with motor conduction velocity or grip and pinch strengths.

CONCLUSIONS

Women with CTS and vitamin D deficiency showed subtle but better DASH scores after surgery when vitamin D deficiency was corrected by supplementation.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Effect of Alpha-Lipoic Acid on Clinical and Neurophysiologic Recovery of Carpal Tunnel Syndrome: A Double-Blind, Randomized Clinical Trial

The objective of our study was to examine the effect of alpha-lipoic acid (ALA) on clinical and neurophysiologic outcomes after surgery for idiopathic carpal tunnel syndrome (CTS). We conducted a randomized, double-blind, placebo-controlled clinical trial in 20 adults diagnosed with idiopathic CTS after clinical and neurophysiologic assessment. Eligible participants took 600 mg ALA or placebo per day for 1 month before surgery, and for 2 months afterward. Further clinical and neurophysiologic assessments were undertaken immediately before surgical decompression, and at 12 weeks postoperatively with additional clinical assessments at the 4th and 8th week after surgery. Clinical outcome measures were taken by Boston Questionnaire score, the presence or absence of Tinel's sign, and Phalen's test findings. Median nerve conduction studies were also undertaken and interpreted according to Dumitru's reference values. Nineteen patients completed the study; one member of the placebo group was lost during follow-up. There were significant improvements in clinical and neurophysiologic variables in the ALA treatment group, present even before surgery. Boston Questionnaire scores had improved significantly in both groups. In the ALA group, none of the participants had positive Phalen's or Tinel's signs at 12 weeks, and motor and sensory fiber latency and amplitude had significantly improved; in the placebo group, only the sensory distal latency had improved significantly. In conclusion, ALA administered 1 month before open decompression and for 2 months afterward improves the clinical and neurophysiologic outcomes after surgery.

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.

Evolución electrofisiológica en pacientes con síndrome del túnel del carpo tratados con cirugía

<p>Antecedentes. En la liberación del síndrome de túnel del carpo (STC) los estudios electrodiagnósticos pueden cuantificar la gravedad de la enfermedad. Hasta la fecha, los reportes de estudios que evalúan la evolución electrofisiológica como resultado objetivo de la cirugía de descompresión son controvertidos, de hecho la correlación entre estas pruebas y la percepción clínica de mejoría ha sido descrita como modesta. Objetivos. Evaluar el comportamiento de los parámetros electrofisiológicos en una serie de pacientes operados del síndrome de túnel del carpo y determinar las variables electrofisiológicas de mejor rendimiento. Materiales y métodos. Estudio observacional analítico retrospectivo de pacientes operados ambulatoriamente por síndrome de túnel del carpo y evaluados con estudios electrodiagnósticos antes y después de la cirugía. Resultados. Se analizaron 48 pacientes con edad promedio de 48 años. El 52% de pacientes mejoraron según la escala de Padua. Las latencias distales motoras y sensitivas y el delta sensitivo del nervio mediano mejoraron después de cirugía con resultados estadísticamente significativos. Las latencias del nervio cubital no variaron. Conclusiones. La mejoría de los parámetros electrofisiológicos después de una liberación de síndrome de túnel del carpo es controversial: algunos reportes muestran mejoría desde el primer mes, especialmente en la velocidad de conducción sensitiva. Otros estudios muestran mejoría significativa entre las semanas 18 y 42 postoperatorias, siendo la recuperación motora más rápida que la sensitiva. En el presente estudio el 52% de los pacientes mejoraron en las escalas por disminución del grado de severidad. Las latencias distales motoras y sensitivas y el delta sensitivo del nervio mediano evidenciaron una mejoría. Estos resultados sugieren que los estudios electrodiagnóstico son efectivos en la evaluación objetiva de pacientes con síndrome de túnel del carpo y es el único examen que puede demostrar mejoría luego de una liberación del STC.</p>

Similar effectiveness of the open versus endoscopic technique for carpal tunnel syndrome: a prospective randomized trial

This prospective randomized study aims at evaluating the electrophysiological results of endoscopic and open carpal ligament release in patients with carpal tunnel syndrome. Included in the study were 41 patients diagnosed with carpal tunnel syndrome (21 hands in the endoscopic group and 20 hands in the open group). The Boston questionnaire was administered preoperatively and postoperatively to the patients, and their functional capacities and symptom severities were recorded. Physical examination was carried out preoperatively and in the postoperative sixth month. Demographic data and preoperative Boston symptomatic and functional scores were similar between both groups. A significant improvement was obtained in the Boston symptomatic and functional scores of both groups, but no significant difference was found between the groups in terms of improvement in the symptomatic and the functional scores. A significant shortening in median nerve motor distal latency and an increase in the velocity of sensory conductions were determined in both groups in the postoperative electromyography, but no difference was found between them in terms of improvement in the electromyography values. It was shown both clinically and electrophysiologically that endoscopic carpal tunnel surgery was as effective as open surgery as a treatment method for carpal tunnel syndrome.

Median nerve superficial to the transverse carpal ligament

Recurrent carpal tunnel syndrome occurs in up to 12% of cases after carpal tunnel release. Recurrent carpal tunnel syndrome is defined as recurrence of classic symptoms confirmed by electrodiagnostic studies after a symptom-free interval of a minimum of 6 months, as opposed to persistent carpal tunnel syndrome, where a symptom-free interval never occurs after carpal tunnel release, which is attributed to incomplete release of the transverse carpal ligament. The most common causes of recurrent carpal tunnel syndrome requiring reoperation are incomplete release of the transverse carpal ligament and scarring of the median nerve to the surrounding structures. Surgical exploration, release of the reconstituted transverse carpal ligament, and freeing of the median nerve from constricting scar will usually result in symptom relief. The authors describe an unusual presentation of recurrent carpal tunnel syndrome with healing of the transverse carpal ligament dorsal to the median nerve, trapping the median nerve in the subcutaneous tissue. Hand surgeons must be aware of this anomalous location when performing revision carpal tunnel release. The surgeon must locate the median nerve proximally in normal tissue before proceeding distally to avoid iatrogenic injury during revision carpal tunnel release.

Effect of synovial transthyretin amyloid deposition on preoperative symptoms and postoperative recovery of median nerve function among patients with idiopathic carpal tunnel syndrome

BACKGROUND

The clinical characteristics of wild-type transthyretin amyloid deposition among patients with carpal tunnel syndrome (CTS) have not been well investigated.

METHODS

One-hundred and seven patients with idiopathic CTS who underwent carpal tunnel release were enrolled. They underwent physical examination of the hand, nerve-conduction study, and magnetic resonance imaging (MRI) study of the wrist, and completed a patient-oriented questionnaire. The tests, except for MRI, were repeated 1, 3, and 6 months postoperatively. Synovial tissue was obtained during surgery and analyzed by Congo red and immunohistochemical staining. Ordinal logistic regression analysis was used to evaluate the significance of different clinical and subjective findings between patients with and without amyloid deposition. Postoperative improvements were also compared.

RESULTS

Wild-type transthyretin amyloid deposition was observed for 38 patients. Greater symptom severity and 2-point discrimination scores, and larger cross-sectional areas of the carpal tunnel, were significantly correlated with a larger amount of preoperative amyloid deposition. However, the presence and amount of preoperative amyloid deposition did not affect postoperative improvements in physical findings and nerve-conduction studies.

CONCLUSIONS

Although transthyretin amyloid deposition can worsen CTS symptoms, postoperative improvements were similar for patients with and without this deposition.

Endoscopic release for carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is the most common compressive neuropathy of the upper extremity. It is caused by increased pressure on the median nerve between the transverse carpal ligament and the carpal bones. Surgical treatment consists of the release of the nerve by cutting the transverse carpal ligament. This can be done either with an open approach or endoscopically.

OBJECTIVES

To assess the effectiveness and safety of the endoscopic techniques of carpal tunnel release compared to any other surgical intervention for the treatment of CTS. More specifically, to evaluate the relative impact of endoscopic techniques in relieving symptoms, producing functional recovery (return to work and return to daily activities) and reducing complication rates.

SEARCH METHODS

This review fully incorporates the results of searches conducted up to 5 November 2012, when we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE and EMBASE. There were no language restrictions. We reviewed the reference lists of relevant articles and contacted trial authors. We also searched trial registers for ongoing trials. We performed a preliminary screen of searches to November 2013 to identify any additional recent publications.

SELECTION CRITERIA

We included any randomised controlled trials (RCTs) and quasi-RCTs comparing endoscopic carpal tunnel release (ECTR) with any other surgical intervention for the treatment of CTS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by the Cochrane Collaboration.

MAIN RESULTS

Twenty-eight studies (2586 hands) were included. Twenty-three studies compared ECTR to standard open carpal tunnel release (OCTR), five studies compared ECTR with OCTR using a modified incision, and two studies used a three-arm design to compare ECTR, standard OCTR and modified OCTR.At short-term follow-up (three months or less), only one study provided data for overall improvement. We found no differences on the Symptom Severity Scale (SSS) (scale zero to five) (five studies, standardised mean difference (SMD) -0.13, 95% CI -0.47 to 0.21) or on the Functional Status Scale (FSS) (scale zero to five) (five studies, SMD -0.23, 95% CI -0.60 to 0.14) within three months postoperatively between ECTR and OCTR. Pain scores favoured ECTR over conventional OCTR (two studies, SMD -0.41, 95% CI -0.65 to -0.18). No difference was found between ECTR and OCTR (standard and modified) when pain was assessed on non-continuous dichotomous scales (five studies, RR 0.69, 95% CI 0.33 to 1.45). Also, no difference was found in numbness (five studies, RR 1.14; 95% CI 0.76 to 1.71). Grip strength was increased after ECTR when compared with OCTR (six studies, SMD 0.36, 95% CI 0.09 to 0.63). This corresponds to a mean difference (MD) of 4 kg (95% CI 1 to 6.9 kg) when compared with OCTR, which is probably not clinically significant.In the long term (more than three months postoperatively) there was no significant difference in overall improvement between ECTR and OCTR (four studies, RR 1.04, 95% CI 0.95 to 1.14). SSS and FSS were also similar in both treatment groups (two studies, MD 0.02, 95% CI -0.18 to 0.22 for SSS and MD 0.01, 95% CI -0.14 to 0.16 for FSS). ECTR and OCTR did not differ in the long term in pain (six studies, RR 0.88, 95% CI 0.57 to 1.38) or in numbness (four studies, RR 0.64, 95% CI 0.31 to 1.35). Results from grip strength testing favoured ECTR (two studies, SMD 1.13, 95% CI 0.56 to 1.71), corresponding to an MD of 11 kg (95% CI 6.2 to 18.81). Participants treated with ECTR returned to work or daily activities eight days earlier than participants treated with OCTR (four studies, MD -8.10 days, 95% CI -14.28 to -1.92 days).Both treatments were equally safe with only a few reports of major complications (mainly with complex regional pain syndrome) (15 studies, RR 1.00, 95% CI 0.38 to 2.64).ECTR resulted in a significantly lower rate of minor complications (18 studies, RR 0.55, 95% CI 0.38 to 0.81), corresponding to a 45% relative drop in the probability of complications (95% CI 62% to 19%). ECTR more frequently resulted in transient nerve problems (ie, neurapraxia, numbness, and paraesthesiae), while OCTR had more wound problems (ie, infection, hypertrophic scarring, and scar tenderness). ECTR was safer than OCTR when the total number of complications were assessed (20 studies, RR 0.60, 95% CI 0.40 to 90) representing a relative drop in the probability by 40% (95% CI 60% to 10%).Rates of recurrence of symptoms and the need for repeated surgery were comparable between ECTR and OCTR groups.The overall risk of bias in studies that contribute data to these results is rather high; fewer than 25% of the included studies had adequate allocation concealment, generation of allocation sequence or blinding of the outcome assessor.The quality of evidence in this review may be considered as generally low. Five of the studies were presented only as abstracts, with insufficient information to judge their risk of bias. In selection bias, attrition bias or other bias (baseline differences and financial conflict of interest) we could not reach a safe judgement regarding a high or low risk of bias. Blinding of participants is impossible due to the nature of interventions.We identified three further potentially eligible studies upon updating searches just prior to publication. These compared ECTR with OCTR (two studies) or mini-open carpal tunnel release (one study) and will be fully assessed when we update the review.

AUTHORS' CONCLUSIONS

In this review, with support from low quality evidence only, OCTR and ECTR for carpal tunnel release are about as effective as each other in relieving symptoms and improving functional status, although there may be a functionally significant benefit of ECTR over OCTR in improvement in grip strength. ECTR appears to be associated with fewer minor complications compared to OCTR, but we found no difference in the rates of major complications. Return to work is faster after endoscopic release, by eight days on average. Conclusions from this review are limited by the high risk of bias, statistical imprecision and inconsistency in the included studies.

A Retrospective Comparison of Conventional versus Transverse Mini-Incision Technique for Carpal Tunnel Release

Background. In this retrospective study, we aimed to compare the results of two surgical techniques, conventional and transverse mini-incision. Materials and Methods. 95 patients were operated between 2011 and 2012 in Bitlis State Hospital. 50 patients were operated with conventional technique and 45 of them were operated with minimal transverse incision. Postoperative complications, incision site problems, and the time of starting to use their hands in daily activities were noted. Results. 95 patients were included in the study. The mean age was 48. 87 of them were female and 8 were male. There was no problem of incision site in both of the two surgical techniques. Only in one patient, anesthesia developed in minimal incision technique. The time of starting to use their hands in daily activities was 22,2 days and 17 days in conventional and minimal incision technique, respectively. Conclusion. Two surgical techniques did not show superiority to each other in terms of postoperative complications and incision site problems except the time of starting to use their hands in daily activities.

Retrospective analysis of five-year and longer clinical and electrophysiological results of the world's first endoscopic management for carpal tunnel syndrome

We have analyzed postoperative long-term follow-up results of five years or more from idiopathic carpal tunnel syndrome patients that underwent our complete carpal canal release and decompression procedure that uses the Universal Subcutaneous Endoscope system. In this series, 203 hands were followed up both clinically and electrophysiologically. Final follow-up times were determined by the most recent electrophysiological measurements. Mean follow-up period was nine years. Tingling, pain (using a 3 gm needle) and touch (using a 2 gm von Frey hair) at all median nerve distribution areas recovered to normal in 92.9, 98.2, 95.2%, respectively. Abductor pollicis brevis muscle power improved from preoperative manual muscle testing of 0, 1, 2 to post-operative 4 or 5 in 82.6%. Mean detectable distal sensory latency improved from 4.3 (n = 130) to 3.1 msec (n = 200). Mean detectable distal motor latency improved from 6.2 (n = 189) to 4.1 msec (n = 200). Complication and recurrence rates were 0% and 0.5% respectively.

Technical difficulties and their prediction in 2-portal endoscopic carpal tunnel release for idiopathic carpal tunnel syndrome

PURPOSE

This study aimed to identify technical difficulties encountered during 2-portal endoscopic carpal tunnel release (ECTR) and to determine their incidence. Furthermore, we assessed the possibility of preoperatively predicting such technical difficulties.

METHODS

We retrospectively reviewed the records of 311 hands of 311 patients with idiopathic carpal tunnel syndrome who underwent ECTR with our modified Chow 2-portal technique. Any technical difficulties during the procedure were reviewed and correlated with preoperative physical findings, nerve conduction studies, and magnetic resonance imaging findings, by use of the t test, χ(2) test, and binary regression analysis.

RESULTS

One or more difficulties were encountered in 139 of 311 hands (44.7%), whereas surgery in the remaining 172 hands (55.3%) was performed without any difficulties. Technical difficulties encountered were as follows: tight access in 61 hands, difficulty in identifying the distal part of the transverse carpal ligament through the exit portal in 35 hands, synovial tissue being caught at the cannula tip when pulling it out of the carpal tunnel in 39 hands, steep angle of the cannula assembly with difficulty in emerging from the exit portal in 29 hands, and other difficulties. Postoperative worsening of symptoms was observed in 8 hands (2.6%), in all of which technical difficulties were encountered. Tight access was noted in younger patients and those with a small cross-sectional area at the hook-of-hamate level. The entire ECTR procedure for older female patients was more likely to be easily performed.

CONCLUSIONS

The surgeon may face a variety of technical difficulties during ECTR. Technical difficulties were most often encountered during introduction of the cannula assembly into the carpal tunnel and pulling it out of the exit portal. Older female patients may be the best candidates for 2-portal ECTR.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

The long-term post-operative electromyographic evaluation of patients who have undergone carpal tunnel decompression

We present the electromyographic (EMG) results ten years after open decompression of the median nerve at the wrist and compare them with the clinical and functional outcomes as judged by Levine's Questionnaire. This retrospective study evaluated 115 patients who had undergone carpal tunnel decompression at a mean of 10.47 years (9.24 to 11.36) previously. A positive EMG diagnosis was found in 77 patients (67%), including those who were asymptomatic at ten years. It is necessary to include both clinical and functional results as well as electromyographic testing in the long-term evaluation of patients who have undergone carpal tunnel decompression particularly in those in whom revision surgery is being considered. In doubtful cases or when there are differing outcomes, self-administered scales such as Levine's Questionnaire should prevail over EMG results when deciding on the need for revision surgery.

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.

Electrophysiological responsiveness and quality of life (QuickDASH, CTSI) evaluation of surgically treated carpal tunnel syndrome

BACKGROUND

We evaluated the correlation between Japanese versions of patient-oriented questionnaires and electrophysiological examinations in patients with carpal tunnel syndrome (CTS).

METHODS

A series of 45 patients who were diagnosed with carpal tunnel syndrome and subsequently underwent carpal tunnel release surgery were analyzed. There were 8 men and 37 women with an average age of 64.8 years. They completed the Japanese Society for Surgery of the Hand version of the Carpal Tunnel Syndrome Instrument (CTSI-JSSH), which consisted of a Symptom Severity Score (CTSI-JSSH-SS), Functional Score (CTSI-JSSH-FS), and Japanese Society for Surgery of the Hand version-Quick Disability of Arm, Shoulder, and Hand questionnaire (QuickDASH-JSSH) both preoperatively and 3 months postoperatively. Nerve conduction studies (NCSs) were also performed and included motor distal latency (MDL) and sensory nerve conduction velocity (SCV) measurements. The responsiveness of each instrument was evaluated by calculating the standardized response mean (SRM) and effect size (ES). Correlation coefficients between preoperative and postoperative questionnaire scores and NCS parameters were calculated.

RESULTS

Responsiveness (SRM/ES) was as follows: CTSI-JSSH-SS (-1.06/-1.14), CTSI-JSSH-FS (-0.75/-0.74), Quick-DASH-JSSH (-0.65/-0.62), MDL (-1.45/-1.11), and the neurophysiological stage of the disease (-0.90/-1.42). No significant correlation was observed between the preoperative and postoperative patient-oriented questionnaires and nerve conduction studies (P > 0.05).

CONCLUSIONS

Although NCSs and the Japanese version of patient-oriented questionnaires are highly responsive to treatment, they are not parallel. Multifaceted assessment of CTS treatment is possible by performing both outcome measurements.

LONG-TERM FOLLOW-UP OF DUAL-PORTAL ENDOSCOPIC RELEASE OF THE TRANSVERSE LIGAMENT IN CARPAL TUNNEL SYNDROME

OBJECTIVE

The long-term efficacy of dual-portal endoscopic release of the transverse ligament in carpal tunnel syndrome is still being debated. In this study, the authors present 94 endoscopic carpal tunnel surgery cases with long-term follow-up data.

METHODS

The study includes 72 patients aged 17 to 86 years (mean age, 53.4 years); bilateral surgery was performed in 22 of these patients. Seventy-two hands of female patients and 22 hands of male patients were included. All procedures were performed with a dual-portal set according to the Chow technique. All patients were examined 2 to 3 months after surgery. The long-term follow-up evaluation was based on telephone interviews 5 to 12 years (mean, 8.2 years) after surgery.

RESULTS

From a cohort of 214 cases that were treated surgically between 1995 and 2002, 94 cases (44%) could be evaluated for long-term follow-up. Four of these patients had to be excluded from long-term follow-up because of a switch to an open technique and early open revision (3–6 months after the first surgery), owing to persistent symptoms. A good to optimal postoperative outcome with improvement of neurological signs and subjective patient satisfaction was observed in 84 (93.3%) of the remaining 90 cases. There were no recurrences.

CONCLUSION

The study shows that dual-portal endoscopic release of the transverse ligament in carpal tunnel syndrome is a valuable technique that produces very good long-term results and high patient satisfaction and does not result in a significant recurrence rate.

Short-term electrophysiological conduction change in median nerve fibres after carpal tunnel release

Standard electrophysiological techniques and analysis of the stimulus-response relationship (i.e., the input-output (I-O) curves) of the median nerve were performed in 16 patients with carpal tunnel syndrome (CTS) both prior to and 1 and 6 months after surgical decompression at the wrist. One month after carpal tunnel release (CTR), conduction in cutaneous and motor axons (i.e., sensory conduction velocity and distal motor latency) was found to be improved with respect to pre-surgical values, whereas motor action potentials and the motor I-O curve showed a decrease with respect to control values. This suggested reduced efficiency of axon recruitment following CTR. Six months after surgery, all parameters were significantly improved with respect to control values. The sensory and motor I-O curves suggested that the reduced motor fibre recruitment efficiency observed 1 month after CTR was due to changes in current density distributions under the surface stimulating electrode on the median nerve at the wrist. Slight transient compression (such as that due to post-surgical oedema) acting on median fibres located superficially within the nerve cannot be excluded, however. Since electrophysiological studies are an important, objective method of evaluating the outcome of surgical CTR, electrophysiologists must be aware of the possibility of reduced compound motor action potential (CMAP) in the first few months after surgery.

Reducing neurologic and vascular complications of endoscopic carpal tunnel release using a modified chow technique

PURPOSE

To reduce the rate of median nerve injury occurring during Chow's original 2-portal technique, we developed a modified procedure. The surgical technique was introduced, and the results were evaluated with regard to the clinical findings, nerve conduction studies, and Disabilities of the Arm, Shoulder, and Hand (DASH) score.

METHODS

We analyzed 119 hands of 119 patients with idiopathic carpal tunnel syndrome who underwent our procedure, wherein a cannula assembly was inserted after a partial division of both distal and proximal parts of the transverse carpal ligament through the entry and exit portals. Postoperative examinations, including evaluation of numbness, grip strength, pinch strength, tenderness over and around the wounds, and nerve conduction studies, were performed at 1 month (n = 119), 3 months (n = 119), 6 months (n = 102), and 12 months (n = 39). The DASH score was also evaluated preoperatively and at 3, 6, or 12 months postoperatively. The rate of structural damage to the median nerve, the tendon, and the artery was calculated.

RESULTS

The patients resumed their daily activities or work by 13 days postoperatively. Tenderness around the wounds was detected in 66% of patients by 3 months postoperatively. Numbness disappeared or decreased in 99% of patients by 6 months postoperatively. The DASH score was available for 82 patients, and it improved from 28.2 to 18.3 points postoperatively. Nerve conduction studies indicated a significant decrease in motor distal latency postoperatively. Temporal worsening of median nerve function was observed in 2 patients; however, no structural damage to the nerve, tendon, or artery was observed.

CONCLUSIONS

We found no injury to the tendon or artery and no laceration to the nerve in all 119 patients. However, temporal worsening of median nerve function was observed in 2 patients.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Dual-portal endoscopic release of the transverse ligament in carpal tunnel syndrome: results of 411 procedures with special reference to technique, efficacy, and complications

OBJECTIVE

Endoscopic release of carpal tunnel syndrome is still under debate. The main advantages of the technique are considered to be minor postoperative pain and a more rapid postoperative recovery. Disadvantages are thought to be the impossibility of a direct median nerve neurolysis and a higher surgical complication rate, including injury to the median nerve.

METHODS

The results of 411 consecutive endoscopic carpal tunnel procedures performed between March 1995 and September 2004 are presented. All patients were prospectively followed.

RESULTS

In the present series, a success rate of 98.05% was observed. There was no permanent morbidity and, in particular, there was no injury of the median nerve. In four (0.97%) patients, the preoperative symptoms did not improve. In two (0.49%) of these patients, an incomplete release of the carpal ligament occurred. In another four patients (0.97%), a switch to open surgery was required.

CONCLUSION

The present data prove that the endoscopic technique is a safe and reliable technique for carpal tunnel surgery. The data do not support the current discussion of a higher risk of median nerve injury with endoscopic carpal tunnel surgery. Thus, for our group, the endoscopic technique represents the therapy of choice for the primary idiopathic carpal tunnel syndrome.

Quantitative MRI of the wrist and nerve conduction studies in patients with idiopathic carpal tunnel syndrome

OBJECTIVE

To correlate morphological findings of idiopathic carpal tunnel syndrome (CTS) with the function of the median nerve.

METHODS

In this study, 105 wrists of 105 women patients with idiopathic CTS, and 36 wrists of 36 female volunteers were subjected to nerve conduction studies and MRI. Cross sectional area, signal intensity ratio, and the flattening ratio of the median nerve, carpal tunnel area, flexor tendon area, synovial area, and intersynovial space, and the palmar bowing of the transverse carpal ligament (TCL) were quantified by MRI and correlated with the severity of the disease determined by nerve conduction studies.

RESULTS

Cross sectional areas of the median nerve, flexor tendons, and carpal tunnel, and the palmar bowing of the TCL of the CTS groups were greater than in the control group, but differences were not detected among the CTS groups for the area of the flexor tendons and the carpal tunnel. Enlargement, flattening, and high signal intensity of the median nerve at the distal radioulnar joint level were more significant in the advanced than in the earlier stages of the disease. Increase in palmar bowing of the TCL was less prominent in the most advanced group. Linear correlation between the area of the carpal tunnel and palmar bowing of the TCL was noted.

CONCLUSION

Severity of the disease could be judged by evaluating not only longitudinal changes of signal intensity and configuration of the median nerve, but also palmar bowing of the TCL. Increased palmar bowing of the TCL was found to be associated with an increase in the area of the carpal tunnel.

Median Nerve Excursion during Endoscopic Carpal Tunnel Release

OBJECTIVE

Restriction of the excursion of the nerve has been accepted as a pathogenetic element in carpal tunnel syndrome. The goal of this article was to evaluate the median nerve excursion in the carpal tunnel measured as a function of wrist position before and after endoscopic carpal tunnel release (ECTR) on 28 hands of 22 patients.

METHODS

The position of cylindrical stainless steel markers embedded within the median nerve was measured by a direct radiographic technique. Each upper extremity was examined in three wrist positions. Then, endoscopic release with Menon's technique was performed, and the measurements were repeated.

RESULTS

In this prospective clinical study, most (93%) of the patients experienced resolution of their symptoms. Before and after ECTR, median nerve excursion was linear and was affected by wrist position. Before ECTR, when the wrist was moved from the end of dorsiflexion to the end of palmar flexion, the median nerve underwent a mean total excursion of 28.8 mm at the wrist. A comparison of the before and after ECTR excursion showed no statistical differences in the amount of motion.

CONCLUSION

The single-portal ECTR does not seem to influence the median nerve excursion for the wrist positions studied in patients with carpal tunnel syndrome. The results from this in vivo study showed longitudinal gliding of the median nerve twice as great as in in vitro studies.

Median nerve damage during two-portal endoscopic carpal tunnel release

OBJECTIVE

To evaluate the adverse effects of Chow's two-portal endoscopic carpal tunnel release (ECTR) performed by an experienced surgeon on median nerve function in patients with idiopathic carpal tunnel syndrome, as compared to open carpal tunnel release (OCTR).

METHODS

Eighty-seven hands subjected to ECTR and 65 hands subjected to OCTR were reviewed. Both groups of patients were similar with regard to age, gender, and severity of the disease. Both groups were compared for the number of hands showing worsening of motor distal latency, sensory conduction velocity, and sensory disturbance after surgery.

RESULTS

Thirteen hands of 12 patients showed worsening of median nerve function after ECTR, while only one hand showed worsening after OCTR. This difference was statistically significant (p=0.0041).

CONCLUSIONS

Median nerve damage, although transient or not serious, may occur even if the procedure is done correctly.

Evaluation of sensory function after median nerve decompression in carpal tunnel syndrome using the current perception threshold test

The recovery level for sensory function after carpal tunnel release for the treatment of idiopathic carpal tunnel syndrome (CTS) was assessed with the current perception threshold (CPT) test. Seventeen CTS patients (21 hands) were followed, and the CPTs at the index finger of each patient was measured preoperatively and at 1, 3, and 6 months postoperatively. After carpal tunnel release, there was significant recovery of CPT at all stimulation frequencies, indicating improvement of all sensory functions including sensations of temperature, pain, touch, and vibration.

Neurophysiological recovery after open carpal tunnel decompression: comparison of simple decompression and decompression with epineurotomy

Two hundred and seventy-three patients with carpal tunnel syndrome without advanced neurophysiological changes (distal motor latency below 11 ms) were randomized to treatment by open carpal tunnel release with, or without, epineurotomy. Patients were examined clinically and by nerve conduction studies preoperatively and at 3, 6 and 12 months postoperatively. We found no statistically significant difference between simple decompression and decompression combined with epineurotomy with regard to either the clinical or the neurophysiological outcome.

Nerve conduction studies in selected peripheral nerve disorders

PURPOSE OF REVIEW

The physiological properties of nerve and muscle are influenced by pathological changes and the aim of this review is to discuss recent contributions of electrophysiological studies to the understanding and diagnosis of selected peripheral nerve disorders. The relationships between pathology and physiology emphasize the close interdependence between electrophysiological studies, clinical deficits and other laboratory information. Attention should be paid to the strengths and limitations of electrophysiological methods, considering their impact on diagnosis and treatment of patients.

RECENT FINDINGS

Several studies have shown particular pathophysiological profiles associated with different antibody subtypes in autoimmune peripheral neuropathies and this association further supports the suggestion of pathological specificity in both acute and chronic neuropathy. The sensitivity and specificity of physiological profiles therefore become increasingly important since some of these neuropathies are accessible to treatment. On the other hand, the pathophysiological and clinical profiles may be heterogeneous in patients with some disorders. This could be related to a more indistinct division between different types of pathology with increased understanding of pathogenetic mechanisms. Moreover, new insights into disturbed axonal function have stimulated attempts to develop methods to explore normal and diseased human nerve function.

SUMMARY

The exploration of axonal membrane and ion-channel function has become accessible using studies of excitability and are of potential value where conventional studies only provide nonspecific evidence of the number of fibers and the integrity of myelin. These studies will presumably become increasingly important in the years ahead considering the lack of understanding of the functional disturbances in axonal neuropathies.