Median nerve deformation and displacement in the carpal tunnel during finger motion

The objective of this study was to evaluate the correlations between deformation and displacement of median nerve and flexor tendons during finger motion in the carpal tunnel for both carpal tunnel syndrome (CTS) patients and healthy controls. Sixty‐two wrists of 31 asymptomatic volunteers and fifty‐one wrists of 28 idiopathic CTS patients were evaluated by ultrasound. The displacement of the median nerve and the middle finger flexor digitorum superficialis (FDS) tendon, as well as area, perimeter, aspect ratio of a minimum enclosing rectangle, and circularity of the median nerve were measured in finger extension and flexion positions. Deformation indices were defined as the ratios of indices in finger extension and flexion positions. The correlations between displacement and deformation indices were evaluated. There were significant correlations between nerve palmar–dorsal displacement and deformation indices (p < 0.05). The aspect ratio deformation index showed the strongest correlation to palmar–dorsal displacement of the nerve (?0.572, p < 0.01). This study showed that there is a relationship between median nerve deformation indices and nerve palmar–dorsal displacement in the carpal tunnel. Since the highest correlations were between palmar–dorsal nerve displacement direction and aspect ratio deformation index, these parameters may be helpful to understand the pathophysiology of CTS. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1876–1880, 2013

     

Median nerve deformation and displacement in the carpal tunnel during index finger and thumb motion

The purpose of this study was to investigate the deformation and displacement of the normal median nerve in the carpal tunnel during index finger and thumb motion, using ultrasound. Thirty wrists from 15 asymptomatic volunteers were evaluated. Cross‐sectional images during motion from full extension to flexion of the index finger and thumb were recorded. On the initial and final frames, the median nerve, flexor pollicis longus (FPL), and index finger flexor digitorum superficialis (FDS) tendons were outlined. Coordinate data were recorded and median nerve cross‐sectional area, perimeter, aspect ratio of the minimal‐enclosing rectangle, and circularity in extension and flexion positions were calculated. During index finger flexion, the tendon moves volarly while the nerve moves radially. With thumb flexion, the tendon moves volarly, but the median nerve moves toward the ulnar side. In both motions, the area and perimeter of the median nerve in flexion were smaller than in extension. Thus, during index finger or thumb flexion, the median nerve in a healthy human subject shifts away from the index finger FDS and FPL tendons while being compressed between the tendons and the flexor retinaculum in the carpal tunnel. We are planning to compare these data with measurements in patients with carpal tunnel syndrome (CTS) and believe that these parameters may be useful tools for the assessment of CTS and carpal tunnel mechanics with ultrasound in the future. Published by Wiley Periodicals, Inc. J Orthop Res 28:1387–1390, 2010     

Median nerve deformation in differential finger motions: ultrasonographic comparison of carpal tunnel syndrome patients and healthy controls

We investigated the median nerve deformation in the carpal tunnel in patients with carpal tunnel syndrome and controls during thumb, index finger, middle finger, and a four finger motion, using ultrasound. Both wrists of 29 asymptomatic volunteers and 29 patients with idiopathic carpal tunnel syndrome were evaluated by ultrasound. Cross‐sectional images during motion from full extension to flexion were recorded. Median nerve cross‐sectional area, perimeter, aspect ratio of the minimal enclosing rectangle, and circularity in extension and flexion positions were calculated. Additionally, a deformation index was calculated. We also calculated the intra‐rater reliability. In both controls and patients, the median nerve cross‐sectional area became significantly smaller from extension to flexion in all finger motions (p < 0.05). In flexion and extension, regardless of the specific finger motion, the median nerve deformation, circularity and the change in perimeter were all significantly greater in CTS patients than in controls (p < 0.05). We found excellent intra‐rater reliability for all measurements (ICC > 0.84). With this study we have shown that it is possible to assess the deformation of the median nerve in carpal tunnel syndrome with ultrasonography and that there is more deformation of the median nerve in carpal tunnel syndrome patients during active finger motion. These parameters might be useful in the evaluation of kinematics within the carpal tunnel, and in furthering our understanding of the biomechanics of carpal tunnel syndrome in the future. © 2011 Orthopaedic Research Society. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:643–648, 2012     

The anatomical site of constriction of the median nerve in patients with severe idiopathic carpal tunnel syndrome

During open carpal tunnel release in patients with severe idiopathic carpal tunnel syndrome, an area of constriction in the substance of the median nerve is frequently noted. In a prospective study of 30 patients, the central point of the constricted part of the nerve was determined intraoperatively and found to be, on average, 2.5 (range 2.2-2.8)cm from the distal wrist crease. This point always corresponded to the location of the hook of the hamate bone. These intraoperative findings were compared with the "narrowest" point of the carpal canal as determined by anatomical and radiological studies in the literature.     

Results of treatment of carpal tunnel syndrome with associated hourglass deformity of the median nerve

Two hundred twenty-seven successive cases of carpal tunnel syndrome confirmed by abnormal electrodiagnostic studies were reviewed. All cases underwent open carpal tunnel release by a single surgeon over a 3-year period. Thirty-two hands (14% of all cases) in 29 patients demonstrated an hourglass deformity at the time of surgery. Electrodiagnostic tests revealed no evidence of any other type of peripheral neuropathy in any patient. Postoperative electrodiagnostic studies were obtained in all cases on completion of therapy. The length of the follow-up period averaged 11 months (range, 3-35 months). The duration of preoperative symptoms ranged from 2 years to more than 10 years. Twenty-eight of the 32 hands (88%) with hourglass deformities demonstrated subjective clinical improvement or complete resolution of symptoms. Chronicity of symptoms and electrophysiologic severity did not correlate with the presence of the hourglass deformity. Presence of hourglass compression of the median nerve in carpal tunnel syndrome is therefore not a negative prognostic indicator.     

The effect of tendon excursion velocity on longitudinal median nerve displacement: Differences between carpal tunnel syndrome patients and controls

The subsynovial connective tissue (SSCT) is a viscoelastic structure connecting the median nerve (MN) and the flexor tendons in the carpal tunnel. Increased strain rates increases stiffness in viscoelastic tissues, and thereby its capacity to transfer shear load. Therefore, tendon excursion velocity may impact the MN displacement. In carpal tunnel syndrome (CTS) the SSCT is fibrotic and may be ruptured, and this may affect MN motion. In this study, ultrasonography was performed on 14 wrists of healthy controls and 25 wrists of CTS patients during controlled finger motions performed at three different velocities. Longitudinal MN and tendon excursion were assessed using a custom speckle tracking algorithm and compared across the three different velocities. CTS patients exhibited significantly less MN motion than controls (p ≤ 0.002). While in general, MN displacement increased with increasing tendon excursion velocity (p ≤ 0.031). These findings are consistent with current knowledge of SSCT mechanics in CTS, in which in some patients the fibrotic SSCT appears to have ruptured from the tendon surface. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:483–487, 2015.     

Carpal arch and median nerve changes during radioulnar wrist compression in carpal tunnel syndrome patients

The purpose of this study was to investigate the morphological changes of the carpal arch and median nerve during the application of radiounlarly directed compressive force across the wrist in patients with carpal tunnel syndrome. Radioulnar compressive forces of 10 N and 20 N were applied at the distal level of the carpal tunnel in 10 female patients diagnosed with carpal tunnel syndrome. Immediately prior to force application and after 3 min of application, ultrasound images of the distal carpal tunnel were obtained. It was found that applying force across the wrist decreased the carpal arch width (p < 0.001) and resulted in increased carpal arch height (p < 0.01), increased carpal arch curvature (p < 0.001), and increased radial distribution of the carpal arch area (p < 0.05). It was also shown that wrist compression reduced the flattening of the median nerve, as indicated by changes in the nerve's circularity and flattening ratio (p < 0.001). This study demonstrated that the carpal arch can be non‐invasively augmented by applying compressive force across the wrist, and that this strategy may decompress the median nerve providing symptom relief to patients with carpal tunnel syndrome. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1234–1240, 2016.     

腕管切开松解减压术

腕管切开松解减压术一直被认为是外科治疗腕管综合征的经典方法，于1913年由Marie和Foix最先提出。其术式甚多，优、缺点各异，操作也有简有繁。现结合腕部神经解剖特点，将每一种术式归纳复述如下。     

Acute carpal tunnel syndrome due to a hemangioma of the median nerve

Hemangioma of the median nerve presenting as acute carpal tunnel syndrome is unusual A-18- year old male presented with severe incapacitating pain of sudden onset of left forearm and hand after manual field work. There was swelling on volar aspect of forearm, with hyperalgesia in the median nerve distribution. The fingers and wrist were inmarked flexion and the patient did not allow wrist and finger extension. X-rays were within normal limits. An emergency volar carpal ligament release revealed, haematoma about 100 ml with numerous vessels encircling the median nerve. Histopathology of lesion turned out to be a cavernous hemangioma. Post operatively patient had full recovery.     

Bilateral palmaris profundus in association with bifid median nerve as a cause of failed carpal tunnel release

This is a case in which an anomalous tendon of the palmaris profundus was found running on the anterior surface of the median nerve, dividing the nerve into 2 branches at the wrist bilaterally. Excision of the tendon at the time of re-exploration of the carpal tunnel resulted in complete relief of carpal tunnel symptoms.     

Palmaris profundus tendon prohibiting endoscopic carpal tunnel release: case report

Palmaris profundus is an aberrant muscle of forearm and wrist anatomy. It has no discernible function, but its tendon has been implicated as a cause of carpal tunnel syndrome. Previously, all cases of palmaris profundus in the literature have been encountered during either open surgery or cadaveric dissection. We report a case of palmaris profundus encountered during attempted single-portal endoscopic carpal tunnel release, necessitating conversion to an open approach. There was a unique point of tendon insertion onto the undersurface of the transverse carpal ligament, more proximal than what has been previously described in the literature. There were other anomalies present as well, including a persistent median artery and bifid median nerve. Given the volar position of the structure, its proximal point of insertion, and its minimal bulk, we did not feel that this was the cause of our patient's carpal tunnel syndrome.     

Surgical efficacy of carpal tunnel release for carpal tunnel syndrome in acromegaly: report of four patients

Although carpal tunnel syndrome is frequent in acromegaly, few acromegalics will be encountered by most hand surgeons. This paper considers the treatment of four cases of acromegaly in whom carpal tunnel syndrome arose, to discuss aspects of management of carpal tunnel syndrome in this patient group.     

A cost-utility analysis of open and endoscopic carpal tunnel release

BACKGROUND

Open carpal tunnel release (OCTR) is the standard procedure for the surgical treatment of carpal tunnel syndrome. With the advent of minimally invasive surgery, endoscopic carpal tunnel release (ECTR) was introduced.

OBJECTIVE

To use a decision analytical model to compare ECTR with OCTR in an economic evaluation.

METHODS

Direct medical costs were obtained from a Canadian university hospital. Utility values obtained from experts, presented with carpal tunnel syndrome outcome health states, were transformed into quality-adjusted life years (QALYs). The probabilities of the health states associated with both techniques were obtained from the literature.

RESULTS

The incremental cost-utility ratio (ICUR) was $124,311.32/QALY gained, providing strong evidence to reject ECTR when ECTR is performed in the main operating room and OCTR is performed in the day surgery unit. A one-way sensitivity analysis in the present study demonstrated that when both OCTR and ECTR are performed in day surgery unit, the ICUR falls in the ‘win-win’ quadrant, making ECTR both more effective and less costly than OCTR. If the scar tenderness probability is decreased in the ECTR group in a second one-way sensitivity analysis, the ICUR decreases to $100,621.91/QALY gained, providing evidence to reject ECTR. If the reflex sympathetic dystrophy probability is increased in the ECTR group in a third one-way sensitivity analysis, the ICUR increases to $202,657.88/QALY gained, providing strong evidence to reject ECTR.

CONCLUSIONS

There is still uncertainty associated with the costs and effectiveness of ECTR and OCTR. To obtain a definitive answer as to whether the ECTR is more effective than the OCTR, it is necessary to perform a large, randomized, controlled trial in which the utilities and resource use are measured prospectively.     

Electromyographic evaluation after endoscopic carpal tunnel release in idiopathic carpal tunnel syndrome

The purpose of this study was to electromyographically evaluate results in patients with carpal tunnel syndrome (CTS) who underwent endoscopic carpal tunnel release (ECTR). The subjects were 26 patients with idiopathic CTS (37 hands) who were followed for at least 6 months after ECTR. To compare results informatively, hands were classified into four groups: those with normal distal motor latency (DML) and sensory conduction velocity (SCV) were classified as group A, those with normal DML and abnormal SCV as group B, those with an abnormal DML and normal SCV as group C, and those with abnormal DML and SCV as group D. All but one of the hands were classified as group D on the basis of preoperative electromyographic evaluation, while one was classified as group C. The mean preoperative obtainable DML and SCV values were 7.2 m and 27.3 m/s, respectively. Postoperatively, 12 hands were in group A, 8 hands in group B, 2 hands in group C, and 15 hands in group D. The mean DML and SCV values at final follow-up were 4.3 ms and 40.8 m/s, respectively. Of the 25 hands with muscle atrophy before surgery, 6 hands were in group A, 5 hands were in group B, 1 hand was in group C, and 13 hands were in group D at final follow-up. Thenar muscle atrophy and denervation potentials were present before surgery in 13 of the 15 hands classified as group D at the final follow-up. Received for publication on June 23, 1998; accepted on Oct. 30, 1998     

Patient-reported outcomes after acute carpal tunnel release in patients with distal radius open reduction internal fixation

Background

Acute carpal tunnel syndrome (CTS) is a complication that can develop after distal radius fractures. Our hypothesis tested whether patient-reported outcomes after acute carpal tunnel release (CTR) performed in combination with distal radius fracture open reduction internal fixation (ORIF) are worse than patient-reported outcomes with only elective CTR as measured by the symptom severity and functional status scales of the Boston carpal tunnel questionnaire (BCTQ).

Methods

A retrospective assessment identified 26 patients treated with acute CTR at the same time as distal radius ORIF, no history of pre-existing CTS or CTR, no other injuries, and >12 months follow-up. Sixteen of these patients (Group A) could be contacted and answered the BCTQ. Group A was age- and sex-matched to control patients (Group B) treated with only elective CTR. A case–control study was performed comparing outcomes of both groups.

Results

The average age of patients was 51 ± 15 years, with an average follow-up of Group A at 49 ± 21 months versus Group B at 55 ± 20 months. The mean symptom severity scale score for Group A was 1.4 ± 0.4 and for Group B was 1.4 ± 0.4. The mean functional status scale score for Group A was 1.4 ± 0.5 and for Group B was 1.3 ± 0.4. The mean total BCTQ score for Group A was 26.5 ± 7.5 and for Group B was 24.9 ± 7.5. There were no statistical or clinically significant differences between Group A and Group B for symptom severity, functional status, and total BCTQ scores.

Conclusions

Patients with acute CTR performed at the same time with distal radius ORIF do as well in the long-term as those patients with only elective CTR as measured by the BCTQ. Patients should expect similar recovery of subjective nerve function from acute median nerve dysfunction when CTR is performed with distal radius ORIF as patients with only elective CTR.     

Factors associated with trigger digit following carpal tunnel release

BACKGROUND Trigger digit is a common disorder of the hand associated with carpal tunnel syndrome.Carpal tunnel release(CTR) surgery may be a risk factor for trigger digit development;however,the association between surgical approach to CTR and postoperative trigger digit is equivocal.AIM To investigate patient risk factors for trigger digit development following either open carpal tunnel release(OCTR) or endoscopic carpal tunnel release(ECTR).METHODS This retrospective chart analysis evaluated 967 CTR procedures from 694 patients for the development of postoperative trigger digit.Patients were stratified according to the technique utilized for their CTR,either open or endoscopic.The development of postoperative trigger digit was evaluated at three time points:within 6 mo following CTR,between 6 mo and 12 mo following CTR,and after 12 mo following CTR.Firth's penalized likelihood logistic regression was conducted to evaluate sociodemographic and patient comorbidities as potential independent risk factors for trigger digit.Secondary regression models were conducted within each surgical group to reveal any potential interaction effects between surgical approach and patient risk factors for the development of postoperative trigger digit.RESULTS A total of 47 hands developed postoperative trigger digit following 967 CTR procedures(4.9%).In total,64 digits experienced postoperative triggering.The long finger was most commonly affected.There was no significant difference between the open and endoscopic groups for trigger digit development at all three time points following CTR.Furthermore,there were no significant independent risk factors for postoperative trigger digit;however,within group analysis revealed a significant interaction effect between gender and surgical approach(P=0.008).Females were more likely to develop postoperative trigger digit than males after OCTR(OR=3.992),but were less likely to develop postoperative trigger digit than males after ECTR(OR=0.489).CONCLUSION Patient comorbidities do not influence the development of trigger digit following CTR.Markedly,gender differences for postoperative trigger digit may depend on surgical approach to CTR.     

Patient satisfaction after open carpal tunnel release correlates with depression

PURPOSE: To test the null hypothesis that depression does not correlate with patient satisfaction after open release of electrodiagnostically confirmed carpal tunnel syndrome when controlling for other demographic, disease-related, and psychosocial factors. METHODS: Eighty-two survey respondents who had recovered (minimum 2 years after surgery) from a limited incision open carpal tunnel release completed measures of satisfaction, perceived disability, depression, pain catastrophizing, and pain anxiety. Univariate and multivariate analyses sought predictors of satisfaction and perceived disability from among demographic, disease related, and psychological factors. RESULTS: The average satisfaction score was 8 points (range, 0-10) and the average Disabilities of the Arm, Shoulder, and Hand score was 13 points (range, 0-76). Predictors of greater dissatisfaction included greater depression and the categorical electrophysiologic test rating. Predictors of perceived disability included depression, pain catastrophizing, and static numbness. Depression was the dominant predictor of both satisfaction and perceived disability. CONCLUSIONS: Dissatisfaction and perceived disability after limited open carpal tunnel release for electrodiagnostically confirmed idiopathic carpal tunnel syndrome is predicted primarily by depression and ineffective coping skills and to a lesser degree by clinical or electrophysiologic evidence of advanced nerve damage. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.