Aneurysm of the median artery causing recurrent carpal tunnel syndrome and anatomic review

A patient is presented who had recurrent carpal tunnel syndrome symptoms in his left hand 1 year after having undergone release of the transverse carpal ligament. On exploration, this was found to be due to an aneurysm of a median artery and possibly scarring due to this compression around the branches of the bifurcated median nerve. This represents the first case in the literature to comment on (1) the absence of bilaterality of the anatomic finding and (2) carpal tunnel syndrome relative to median artery aneurysm. With this in mind, a plea is made for careful exploration of the carpal tunnel, maintaining an incision as far to the ulnar side of the median nerve as technically possible with thorough visualization of the contents of the tunnel and any anatomic variance involved. The incidence of the combination of aberrant median artery with high bifurcation of the median nerve is unknown, as is the incidence of aneurysm of the median artery.     

The incidence of recurrence after endoscopic carpal tunnel release

Endoscopic carpal tunnel release has been used to decompress the median nerve in carpal tunnel syndrome for over the past decade, with an advantage (over the traditional "open" release) being decreased pain in the postoperative period. The goals of this study were to attempt to define the recurrence rate after endoscopic carpal tunnel release and to determine if it differs from that of open technique. The charts of 191 consecutive carpal tunnel syndrome patients treated operatively at the University of Missouri were reviewed. For this study, recurrent carpal tunnel syndrome was defined as documented cases in which the symptoms had resolved following surgical release but subsequently recurred, requiring surgical rerelease of the carpal tunnel. All endoscopic releases were performed using the Chow two-portal technique. Statistical analysis was performed using Fisher's exact test. A total of 103 patient hands had open carpal tunnel releases; 88 were endoscopically released. Total follow-up time (from the initial release) averaged 29 months for the open group and 22 months for the endoscopic group. There were no recurrences in the open group and six recurrences in the endoscopic group (7 percent, p = 0.008). All six recurrences were in worker's compensation patients. The median time between endoscopic release and rerelease was 8.5 months. There seems to be a statistically higher incidence of recurrence of carpal tunnel syndrome after endoscopic release compared with the traditional "open" release in our cases. Although the pathogenesis of this increased rate of recurrence is not clear, this should be considered when planning surgical release of the volar carpal ligament for carpal tunnel syndrome.     

Evaluation of the carpal tunnel based on 3-D reconstruction from MRI

While deviated wrist postures have been linked to the development of carpal tunnel syndrome, the relative contributions of posture-related changes in size, shape and volume of the carpal tunnel contribute to median nerve compression are unclear. The purpose of this study was two-fold: (1) to reconstruct the carpal tunnel from MRI data in neutral and non-neutral (30 degrees extension, 30 degrees flexion) wrist postures, and (2) to evaluate errors associated with off-axis imaging. Three-dimensional reconstruction of the carpal tunnels of 8 volunteers from the university community revealed that the orientation of the carpal tunnel was not directly explained by external wrist angle. The average orientation of the carpal tunnel was extended in all postures, ranging from 25 degrees +/-9 degrees in extension, 13 degrees +/-5 degrees in neutral and 4 degrees +/-4 degrees in the flexed wrist. Changing the orientation of the imaging plane to be perpendicular to the reconstructed carpal tunnel revealed that axial images overestimated cross-sectional area by an average of nearly 10% in extension, 4% in neutral and less than 1% in flexion. Similarly, adjusting the imaging plane to be perpendicular to external wrist angle overestimated cross-sectional area by an average of 2% in extension, 4% in neutral and 24% in flexion. Distortion of the carpal tunnel shape also became evident with rotation of the imaging plane. The data suggest that correction for the orientation of the carpal tunnel itself to be more appropriate than relying on external wrist angle. Computerized reconstruction provided detailed anatomic visualization of the carpal tunnel, and has created the framework to develop a biomechanical model of the carpal tunnel. Similar reconstruction of the tissue structures passing through (median nerve and flexor tendons) and entering the carpal tunnel (muscle tissue) will enable evaluation and partitioning of median nerve injury mechanisms.     

Comparison of the Effects of Flexion and Extension of the Thumb and Fingers on the Position and Cross-Sectional Area of the Median Nerve

Objective

To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area.

Methods

Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied.

Results

Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2±0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2±0.9 and 3.1±1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0±0.8 mm) and little finger (1.2±0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5±1.1 mm²).

Conclusions

Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.     

Assessment of Median Nerve Mobility by Ultrasound Dynamic Imaging for Diagnosing Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy and is characterized by median nerve entrapment at the wrist and the resulting median nerve dysfunction. CTS is diagnosed clinically as the gold standard and confirmed with nerve conduction studies (NCS). Complementing NCS, ultrasound imaging could provide additional anatomical information on pathological and motion changes of the median nerve. The purpose of this study was to estimate the transverse sliding patterns of the median nerve during finger movements by analyzing ultrasound dynamic images to distinguish between normal subjects and CTS patients. Transverse ultrasound images were acquired, and a speckle-tracking algorithm was used to determine the lateral displacements of the median nerve in radial-ulnar plane in B-mode images utilizing the multilevel block-sum pyramid algorithm and averaging. All of the averaged lateral displacements at separate acquisition times within a single flexion–extension cycle were accumulated to obtain the cumulative lateral displacements, which were curve-fitted with a second-order polynomial function. The fitted curve was regarded as the transverse sliding pattern of the median nerve. The R² value, curvature, and amplitude of the fitted curves were computed to evaluate the goodness, variation and maximum value of the fit, respectively. Box plots, the receiver operating characteristic (ROC) curve, and a fuzzy c-means clustering algorithm were utilized for statistical analysis. The transverse sliding of the median nerve during finger movements was greater and had a steeper fitted curve in the normal subjects than in the patients with mild or severe CTS. The temporal changes in transverse sliding of the median nerve within the carpal tunnel were found to be correlated with the presence of CTS and its severity. The representative transverse sliding patterns of the median nerve during finger movements were demonstrated to be useful for quantitatively estimating median nerve dysfunction in CTS patients.     

肌电图检查评估腕管综合征手术效果的临床分析

目的:探讨采用肌电图检查评估腕管综合征的手术治疗效果。方法:选取35例(患侧手共39侧)临床确诊为腕管综合征并接受腕管切开减压术治疗的患者,于手术前后分别行肌电图检查,应用正中神经传导检查和拇短展肌针极肌电图检查,分析患者手术前和手术后腕部正中神经功能的变化情况。结果:手术后,患者正中神经感觉传导潜伏期异常率(33%)、正中神经运动传导潜伏期异常率(36%)较手术前(72%、74%)明显下降(P0.05),正中神经感觉传导波幅(7.40±5.05)较手术前(4.86±3.60)显著降低(P0.001),拇短展肌静息状态下失神经电位的异常率(69%)、重收缩时募集电位异常率(13%)均较手术前(85%、26%)明显下降(P0.05)。患者手术前后正中神经感觉传导速度和运动传导速度对比差异无统计学意义(P0.05)。结论:腕管切开减压术可解除正中神经卡压状态,明显恢复正中神经功能,增强拇短展肌肌力,临床治疗效果好。肌电图检查可为腕管综合征患者手术治疗效果的评估提供客观的依据。     

Microvascular omental transfer for the treatment of severe recurrent median neuritis of the wrist: a long-term follow-up

The results of reoperation for recurrent carpal tunnel syndrome have been quite disappointing. In addition to a secondary external or internal neurolysis, multiple tissues and procedures have been used to decrease scar adherence of the reoperated median nerve including muscle, fascial or fat flaps, and vein wrapping. However, each technique has certain limitations, especially in the carpal tunnel that has previously undergone multiple operations, with diffuse scar and adherence over an extended length of the median nerve. The purpose of this study was to evaluate the long-term functional and symptomatic outcome following microvascular omental transfer for severe recalcitrant median neuritis. Between 1989 and 1993, 10 extremities in seven patients underwent omental transfer for severe recurrent median neuritis at the wrist. Nine extremities in six women were available for personal evaluation at an average follow-up of 6.6 years (range, 4.5 to 8.75 years). All extremities had undergone a minimum of two previous surgical procedures, and since 1991, all patients also failed local pedicle tissue coverage. Each patient completed a physical examination, a questionnaire, and electrophysiologic studies. At surgery, all median nerves were encased in dense adherent scar, which often extended proximal to the wrist crease. There were seven neural abnormalities in six extremities, three patent median arteries, and one aberrant palmaris longus muscle. The Functional Status Index was 3.1 +/- 0.7 and the Symptom Severity Index was 3.1 +/- 0.9, with a range of 1 (best) to 5. Most symptoms were improved but not completely alleviated. Four of nine extremities exhibited improved two-point discrimination and five of seven improved sensitivity, according to the Semmes-Weinstein monofilament test. Grip strength increased an average of 73 percent in seven of nine extremities and pinch strength increased 101 percent in four of nine extremities. Five of six patients were satisfied with their results and reported improved quality of life. Preoperatively, five of seven patients were working on light duty; postoperatively, three of six patients attempted to return to work, but none were working at final follow-up. Electrophysiologic data did not correlate with the symptomatic or functional outcome. There were four complications; three were related to delayed wound healing, and one morbidly obese patient developed a ventral hernia. Wrapping the median nerve with vascularized omentum is a viable option for the treatment of severe recalcitrant carpal tunnel syndrome. Despite a high satisfaction rate and significant symptomatic improvement, many symptoms will persist, but to a lesser degree.     

Carpal tunnel syndrome and vitamin B6

We reviewed 1075 patients presenting over a 12-year period with symptoms of carpal tunnel syndrome. A total of 994 had a final diagnosis of carpal tunnel syndrome. There were 444 male and 550 female patients with a mean age of 42 years. Three-hundred and ninety-five related symptoms to their job. Surgery was performed in 27 percent of the total diagnosed cases with approximately 97 percent relief of symptoms. Satisfactory alleviation of symptoms was obtained in 14.3 percent of patients treated conservatively prior to 1980, with one or a combination of splinting anti-inflammatory agents, job or activity change, and steroid injections. In 1980, vitamin B6 (pyridoxine) was added as a method of conservative treatment. Satisfactory improvement was obtained in 68 percent of 494 patients treated with a controlled dosage (100 mg b.i.d.). While our findings were not the result of a controlled scientific study, we feel they suggest that regulated use of vitamin B6 may be helpful in treating many cases of carpal tunnel syndrome.     

Volar/dorsal compressive mechanical behavior of the transverse carpal ligament

Mechanical insult to the median nerve caused by contact with the digital flexor tendons and/or carpal tunnel boundaries may contribute to the development of carpal tunnel syndrome. Since the transverse carpal ligament (TCL) comprises the volar boundary of the carpal tunnel, its mechanics in part govern the potential insult to the median nerve. Using unconfined compression testing in combination with a finite element-based optimization process, nominal stiffness measurements and first-order Ogden hyperelastic material coefficients (μ and α ) were determined to describe the volar/dorsal compressive behavior of the TCL. Five different locations on the TCL were tested, three of which were deep to the origins of the thenar and hypothenar muscles. The average (± standard deviation) low-strain and high-strain TCL stiffness values in compression sites outside the muscle attachment region were 3.6 N/mm (±2.7) and 28.0 N/mm (±20.2), respectively. The average stiffness values at compression sites with muscle attachments were notably lower, with low-strain and high-strain stiffness values of 1.2 N/mm (±0.5) and 9.7 N/mm (±4.8), respectively. The average Ogden coefficients for the muscle attachment region were 51.6 kPa (±16.5) for μ and 16.5 (±2.0) for α, while coefficients for the non-muscle attachment region were 117.8 kPa (±86.8) for μ and 17.2 (±1.6) for α. These TCL compressive mechanical properties can help inprove computational models, which can be used to provide insight into the mechanisms of median nerve injury leading to the onset of carpal tunnel syndrome symptoms.     

Carpal tunnel syndrome caused by hand injuries.

Although carpal tunnel syndrome associated with injury to the wrist is common, it is possible to overlook symptoms of median nerve compression caused by an ascending tenosynovitis secondary to trauma distal to the wrist. One should look for these symptoms in such patients who complain of pain and weakness of the hand, and release the carpal tunnel if nerve compression is suspected.     

神经传导测定技术对腕管综合征病情评估的价值

目的:近年来腕管综合征发病率逐年升高,然而其慢性、隐匿性不易引起人们的重视,发现时往往已造成较大的危害。本文探讨腕管综合征的神经传导测定对病情评估的临床价值,旨在为患者腕管综合征早期发现和后续治疗提供进一步的临床参考依据。方法:选取我院124例确诊的腕管综合征患者。其中无大鱼际肌萎缩者有64例,并选取平均年龄相近的64例正常人作为对照(组A);有大鱼际肌畏缩者60例,并选取平均年龄相近的60例正常人作为对照(组B)。A、B组均经行神经电图检查,握力测定和两点辨别觉测定,分析神经传导速度改变与感觉、运动功能减退程度的关系。结果:A、B两组患者均有不同程度的神经传导改变:在A组患者神经传导改变中,运动和感觉传导速度(MCV和SCV)轻度下降,运动和感觉电位波幅(CMAP和SNAP)轻度下降,潜伏期(ML)轻度延长;在B组患者神经传导中,运动和感觉传导速度(MCV和SCV)明显下降,运动和感觉电位波幅(CMAP和SNAP)明显下降,潜伏期明显延长。结论:腕管综合征患者不同的临床表现有不同程度的神经电图表现,因此神经电图对神经传导的测定结果对腕管综合征患者的病情有良好的评估价值,值得临床推广。     

Comparison of median and radial nerve sensory latencies in the electrophysiological diagnosis of carpal tunnel syndrome

An electrophysiological diagnosis of carpal tunnel syndrome (CTS) was made on the basis of the median sensory nerve action potential (SNAP) alone in 79 of 161 (49.1%) symptomatic hands without electrophysiological evidence of a generalised peripheral neuropathy. Comparison of distal sensory latencies (DSLs) for the median and radial nerves yielded abnormal results in 17 of the remaining hands with normal median nerve DSLs, increasing the electrodiagnostic yield to 59.6%. Carpal tunnel decompression has been performed in seven of these hands, with abnormal intraoperative findings reported in two, while all improved clinically following surgery, substantiating the diagnosis of CTS. Although the technique described here would not appear to increase the electrodiagnostic yield more than comparison of DSLs for the median and ulnar nerves, which has been reported previously, it remains an affective, quick and simple procedure for increasing the sensitivity of the nerve conduction studies.     

Idiopathic carpal tunnel syndrome caused by carpal stenosis.

Computed tomography was used to measure the cross-sectional area of the carpal canals in normal controls of both sexes and in women with idiopathic carpal tunnel syndrome. The women controls had significantly smaller carpal canals than the men controls both proximally and distally. In the patients both the proximal and distal cross-sectional areas were significantly reduced compared with the women controls. The measurements showed that carpal canal stenosis is associated with idiopathic carpal tunnel syndrome, narrowing of the canal is bilateral in patients who have unilateral symptoms, and narrowing is greater in the proximal carpal canal. There was no correlation between age and the size of the canal. The difference in the size of the carpal canal between normal men and women might explain the tendency of women to develop carpal tunnel syndrome. The lack of correlation between age and the size of the canal suggests that stenosis of the carpal canal is inherited rather than acquired. Symptoms arise only later in life, when degenerated changes in the content or the walls of the carpal canal compete with the median nerve for space and its function becomes impaired by compression.     

A fluid-immersed multi-body contact finite element formulation for median nerve stress in the carpal tunnel

Carpal tunnel syndrome (CTS) is among the most important of the family of musculoskeletal disorders caused by chronic peripheral nerve compression. Despite the large body of research in many disciplinary areas aimed at reducing CTS incidence and/or severity, means for objective characterization of the biomechanical insult directly responsible for the disorder have received little attention. In this research, anatomical image-based human carpal tunnel finite element (FE) models were constructed to enable study of median nerve mechanical insult. The formulation included large-deformation multi-body contact between the nerve, the nine digital flexor tendons, and the carpal tunnel boundary. These contact engagements were addressed simultaneously with nerve and tendon fluid-structural interaction (FSI) with the synovial fluid within the carpal tunnel. The effects of pertinent physical parameters on median nerve stress were explored. The results suggest that median nerve stresses due to direct structural contact are typically far higher than those from fluid pressure.     

Comparison of carpal canal pressure in paraplegic and nonparaplegic subjects: clinical implications

The purpose of this study was to evaluate the pressure within the carpal tunnel that was generated with certain tasks in paraplegic versus nonparaplegic subjects. Four groups of subjects were evaluated: 10 wrists in six paraplegic subjects with carpal tunnel syndrome, 11 wrists in six paraplegics without the syndrome, 12 wrists in nine nonparaplegics with the syndrome, and 17 wrists in 11 nonparaplegics without the syndrome. Carpal canal pressures were measured in the wrists in three positions (neutral, 45-degree flexion, 45-degree extension) and during two dynamic tasks [wheelchair propulsion and RAISE (relief of anatomic ischial skin embarrassment) maneuver]. External force resistors were placed over the carpal canal and correlated with internal tunnel pressures. At each wrist position, paraplegics with carpal tunnel syndrome consistently had higher carpal canal pressure than did the other groups at the corresponding wrist position; statistical significance was evident with regard to the neutral wrist position (p < 0.05). Within each group of subjects, wrist extension and wrist flexion produced a statistically significant increase in carpal canal pressure (p < 0.05), compared with the neutral wrist position. Dynamic tasks (wheelchair propulsion and the RAISE maneuver) significantly elevated the carpal canal pressure in paraplegics with carpal tunnel syndrome, compared with the other groups (p < 0.05). Lastly, there is a linear positive correlation between carpal canal pressure and external force resistance.     

Clinical experience with the CO2 laser during carpal tunnel decompression

Scar tissue formation along the cut edges of the transverse carpal ligament has been found to be among the primary causes for persistent median nerve compression following carpal tunnel release with the steel scalpel. Since laser surgery has been shown to be effective in reducing incisional inflammatory reactions, hypertrophic scarring, and postoperative pain and edema, in achieving better hemostasis, the application of the carbon dioxide laser may be a more efficient surgical tool than the steel scalpel for carpal tunnel release. In 46 cases of carpal tunnel syndrome, the carbon dioxide laser was utilized to vaporize the transverse carpal ligament and seal its edges. The patients were then reevaluated at 1 week, 2 weeks, 6 months, 1 year, and 2 years. No intraoperative complications were encountered. Patients reported minimal postoperative pain, rapid return of sensibility, decreased paresthesia, and increased motor function. After 2 years, there have been no recurrent symptoms of median nerve compression in these patients.     

Carpal Tunnel Syndrome in Grocery Checkers: A Cluster of a Work-Related Illness

Grocery checkers must use a high level of repetitive motion in the course of their work. We report a cluster of seven cases of the carpal tunnel syndrome felt to be due to the excessive use of repetitive motion. Each of the grocery checkers had no other identifiable risk factors, and hand pain, physical examination abnormalities and prolonged median nerve sensory latencies had developed that were consistent with the diagnosis of the carpal tunnel syndrome. This cluster of cases, the relation of the history of their disorder to time at work and a review of the literature suggest that grocery checkers, because of their excessively repetitive tasks, are at increased risk for the carpal tunnel syndrome.     

Test of a new technique for the diagnosis of carpal tunnel syndrome.

Several new techniques for carpal tunnel syndrome diagnosis have been developed in the last few years. This work tests a technique that compares the distal motor latency of the median nerve to the second lumbrical muscle (2L) with the distal motor latency of the ulnar nerve to the interossei muscle (INT). Results from 40 normal hands give the superior limit of the normal difference (2L-INT) as 0. 26 ms (&xmacr;+3 SD). In 55 hands with different levels of carpal tunnel syndrome, this new technique was more sensitive and accurate than the conventional test which uses the distal motor latency of the median nerve to the abductor pollicis brevis muscle (APB), especially in the less severe cases. With the absence of the compound muscle action potentials of the APB muscle caused by severe thenar atrophy, it is much easier to obtain the potential from the 2L muscle. We concluded that this is a sensitive, simple, rapid, and non-invasive new technique, and therefore, it should be incorporated as part of the routine ENMG procedures for carpal tunnel syndrome diagnosis.     

The Carpal Tunnel Syndrome—A Review of 100 Patients Treated Surgically

The carpal tunnel syndrome, or compression neuropathy of the median nerve at the wrist, is a common cause of burning pain, numbness and tingling in the hand. The diagnosis is suggested by nocturnal paresthesias in the thumb, index and long fingers associated with signs of irritability of the median nerve in the carpal tunnel at the wrist. Surgical treatment in the form of incision of the transverse carpal ligament should be performed before irreversible motor and sensory changes occur.     

Carpal tunnel syndrome,humeral epicondylitis,and the cervical spine: a study of clinical and dimensional relations.

Forty-three patients with idiopathic carpal tunnel syndrome, confirmed by nerve conduction studies and treated by surgery, were compared clinically and radiologically with 43 age- and sex-matched control patients. Patients with carpal tunnel syndrome had a significantly greater prevalence of lateral humeral epicondylitis (tennis elbow) (33%) than controls (7%). Randomised reading of the cervical spine radiographs in ignorance of the groups to which they belonged showed no significant difference in the prevalence of either intervertebral disc degeneration or intraforaminal osteophyte protruion using conventional grading methods. Measurement of the minimum anteroposterior diameter of the cervical spinal canal, the anteroposterior diameters of the cervical vertebral bodies, and the ratio of intervertebral disc height to adjacent vertebral body height in the cervical spine, however, showed a consistent trend to smaller measurements in the carpal tunnel group. Differences were significant at several vertebral levels in each of these dimensions. The narrowing of the intervertebral discs relative to the vertebral bodies in patients with carpal tunnel syndrome may indicate connective tissue changes, which might also occur in the common extensor origin at the elbow or in the contents of the carpal tunnel.