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Purpose: Our purpose was to compare differences in the incidence of amyloid deposition in tenosynovium (TS) versus transverse carpal ligament (TCL) biopsies obtained during open carpal tunnel release. We hypothesized that the incidence of amyloid would be similar between TCL and TS when obtaining both specimens from the same patient., Methods: All primary, elective open carpal tunnel release cases that underwent biopsy for amyloid between January 2022 and September 2023 were reviewed. Tenosynovial and TCL specimens were independently evaluated by a pathologist to assess for amyloid. Demographic data were collected, and incidence of amyloid deposition was compared between the two samples. Agreement statistics, sensitivity, and specificity were calculated for TCL, using TS as the reference standard., Results: A total of 196 cases met either Tier 1 (n=180) or Tier 2 (n=16) biopsy criteria. Forty-eight cases were excluded for missed biopsies or laboratory processing errors, leaving 148 cases available for analysis. Amyloid deposition was present in 31 out of 148 (21%) TS specimens and 33 out of 148 (22%) TCL specimens. Overall, the results of the TS biopsy agreed with TCL biopsy in 138 out of 148 cases (93%). In the 10 cases for which the results of the TCL and TS biopsy differed, six cases had (+) TCL and (-) TS, and four cases had amyloid deposition in TS without evidence of deposition in the TCL. Sensitivity and specificity values for the TCL specimen were 87% and 95%, respectively. Positive and negative predictive values were 82% and 97%, respectively., Conclusions: For cases of open carpal tunnel release undergoing biopsy, amyloid deposition was noted in 21% of TS specimens and 22% of TCL specimens. Results of TS and TCL biopsies obtained from the same patient agreed in 93% of cases. Single-source biopsy for amyloid represents a reasonable diagnostic approach. Future cost analyses should be performed to determine whether the addition of two biopsy sources to improve diagnostic accuracy is justified., Type of Study/level of Evidence: Prognostic II., Competing Interests: Conflicts of Interest No benefits in any form have been received or will be received related directly to this article., (Copyright © 2024 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: It is thought that local ischemia and oxygen radicals are responsible for fibroblast-to-myofibroblast cell transformation and proliferation. We hypothesized that hypoxia could differentially activate the contractility of fibroblasts from normal human palmar fascia and from fibroblasts-myofibroblasts of Dupuytren cords., Methods: Normal palmar fascia from 5 patients with carpal tunnel syndrome and Dupuytren cords from 5 patients were harvested. Cells were cultured from all tissue samples, and collagen lattices were prepared containing these cells. Oxygen treatment subgroups were created and incubated under hypoxic (1% O(2), 5% CO(2), and 94% N(2)), normoxic (21% O(2), 5% CO(2), and 74% N(2)), and hyperoxic (100% oxygen using 2.4 atm pressure twice a day for 7 d) conditions. After 7 days, each subgroup was photographed, and lattices were released from dishes. Postrelease photographs were taken immediately, 5 minutes after release, and after 1 hour. Areas of the lattices at each time point were calculated using MetaMorph software. Actin staining and live/dead cell analysis was performed. Linear repeated measures analysis of variance was used for data analysis given that contraction levels were measured over 3 distinct time points., Results: We found a statistically significant difference between normal samples and Dupuytren samples in mean contraction levels over time. There was no statistically significant difference between tissue groups over the 3 time periods based on the oxygen treatment received., Conclusions: Our results showed a greater degree of contractility in Dupuytren disease cells than normal fibroblasts. However, the contraction in either group was not affected by oxygen level. Future in vivo research is needed to better understand the nature of pathophysiology of Dupuytren disease., (Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: During endoscopic or open carpal tunnel release, a palmar fat pad is visualized immediately proximal to the distal end of the transverse carpal ligament (TCL). Visualization of the fat pad allows anticipation of complete release of the TCL without unnecessary distal dissection that could risk iatrogenic injury. This study defines the anatomic relationship of the distal edge of the TCL to the fat pad, the superficial palmar arch, and the motor branch of the median nerve., Methods: Eighteen fresh-frozen cadaver hands were dissected, and the proximal aspect of the palmar fat pad, the distal edge of the TCL, the superficial palmar arch, and the motor branch of the median nerve were identified. An electronic caliper was used to measure distances between each structure along the axis of the radial border of the ring finger. A subset of 8 hands was radiographically imaged with fingers flexed and extended (wrist neutral) to determine if finger positioning influenced measurements between marked structures., Results: The proximal aspect of the palmar fat pad is 2.0 mm proximal to the distal edge of the TCL. The distal end of the TCL, as measured along the axis of the radial border of the ring finger is 12.7 mm from the most proximal aspect of the palmar arch and 6.5 mm from the nearest aspect of the motor branch. Flexing the fingers decreases the distance between the distal end of the TCL and the fat pad while not markedly affecting the distance between the TCL and the palmar arch or the motor branch., Conclusions: The palmar fat pad is a reliable anatomic landmark during carpal tunnel release. When dividing the TCL from proximal to distal, visualization of the proximal aspect of the fat pad indicates that the distal edge of the TCL is within approximately 2 mm and indicates that distal dissection beyond this extent is unnecessary.

Purpose: Steroid injections are commonly performed by hand surgeons for relief of symptoms associated with carpal tunnel syndrome. The purpose of this study is to examine the relationship of the needle to the median nerve within the carpal tunnel and to the palmar cutaneous branch, using 2 injection techniques., Methods: Simulated carpal tunnel injections were performed on 15 cadaveric arms using 2 methods. The first injection used a widely accepted approach in which the needle is inserted at the wrist crease, just ulnar to the palmaris longus, and directed at a 30 degrees angle to the horizontal. In the second method, the needle is positioned just ulnar to the palpable ulnar border of flexor carpi radialis and angled 30 degrees to the horizontal. Specimens were dissected using an open carpal tunnel release. Calipers measured the distance from each needle to the median nerve within the carpal tunnel and to the palmar cutaneous branch., Results: Using the first injection method, the needle pierced the median nerve in 4 specimens, and its mean distance from the nerve measured 1.34 mm +/- 1.83 mm. With the second injection method, the median nerve was pierced in 1 specimen, and the needle averaged a distance of 4.79 mm +/- 3.96 mm from the nerve. In the first approach, the needle averaged 9.47 mm +/- 4.11 mm from the palmar cutaneous branch, compared to 1.74 mm +/- 1.59 mm with the second technique., Conclusions: Physicians must exercise caution when performing carpal tunnel injections to avoid intraneural injection. The needle was a statistically significant shorter distance to the median nerve with the traditional injection method; however, the alterative method risks injury to the palmar cutaneous branch of the median nerve.

Purpose: The purposes of this study were as follows: (1) to locate the position of the distal wrist flexion crease with respect to the carpal bones, specifically the proximal pole of the capitate, and (2) to determine the cross-sectional area of the carpal canal proximal and distal to the wrist flexion crease to enable us to determine whether or not there is a focal area of narrowing that would provide an anatomic basis for the proximal extent of carpal tunnel release., Methods: This study had 2 parts. The first part was a plain radiographic study of 21 uninjured wrists in 12 volunteers that defined the position of the distal wrist flexion crease with respect to the carpus. The second part was a magnetic resonance imaging study of 13 wrists in asymptomatic volunteers that measured the cross-sectional area of the carpal canal proximal and distal to the wrist flexion crease., Results: In 19 of 21 wrists the distal wrist flexion crease was within 2 mm of the proximal pole of the capitate. We noted a gradual increase in the area of the carpal canal moving proximal from its narrowest point. There was no significant increase in area until approximately 23 mm proximal to the narrowest point., Conclusions: We noted no focal area of narrowing in the cross-sectional area of the carpal canal either proximal or distal to the wrist flexion crease.

Purpose: The purposes of this study were to determine the distribution of causes and sites of nerve compression in the ulnar tunnel (Guyon's canal), and investigate the relationship between ulnar tunnel syndrome (UTS) and other conditions associated with it., Methods: We performed a retrospective review of 31 patients diagnosed with and treated for UTS to determine the most common cause of compression and the sites of compression, systemic illnesses associated with UTS, and postoperative results., Results: The cause of ulnar nerve compression was idiopathic in 14, trauma in 8, a thrombosis in 2, proliferation of synovium in 2, a prominent hook of the hamate in 1, a schwannoma in 1, postoperative swelling in 1, an aberrant fibrous band in 1, and a ganglion in 1. The sites of compression were classified into 3 zones. Twenty-eight cases had compression in zone 1, 6 in zone 2, and 19 in zone 3. Seventeen cases (55%) had compression in more than 1 zone. Twenty-two cases (71%) were associated with carpal tunnel syndrome (CTS). Twelve (86%) of the 14 idiopathic UTS cases were associated with CTS. The relationship between idiopathic UTS and CTS was not statistically significant. Six cases were associated with diabetes mellitus., Conclusions: The most common cause of UTS in our series was idiopathic. Most idiopathic UTS cases were associated with CTS. The clinical symptoms of UTS improved after surgery in all cases. Therefore because of the presence of multiple compression sites of the ulnar nerve in the hand, for UTS patients we believe that the release of Guyon's canal and/or the pisohamate tunnel is an effective way not only to relieve symptoms but also to determine the real cause of compression.

Purpose: This investigation explored 2 questions. First, does basal joint arthritis lead to morphologic alterations that significantly narrow the carpal tunnel? Second, does trapezial excision alter the morphology of the carpal tunnel and decompress the median nerve?, Method: Four patients with basal joint arthritis alone were treated with ligament reconstruction and tendon interposition (LRTI) arthroplasty. Three patients with basal joint arthritis and carpal tunnel syndrome were treated with LRTI and carpal tunnel release. Preoperative and postoperative magnetic resonance imaging (MRI) scans were obtained to assess differences in carpal tunnel volume and morphology between the groups before and after surgery., Results: The difference in preoperative carpal tunnel volume between groups was not significantly different. Carpal tunnel volume increased by 7% with LRTI and by 24% after LRTI and carpal tunnel release. The anteroposterior diameter of the carpal canal increased in both groups to allow a volar migration of the median nerve., Conclusion: LRTI increases the anteroposterior diameter and volume of the carpal tunnel. A larger comparative study would be necessary to determine whether LRTI is sufficient to decompress the carpal tunnel.

The anatomic relationship between the ulnar artery and transverse carpal ligament (TCL) as an aid in planning for minimally invasive carpal tunnel surgery was investigated. The anatomic course of the ulnar artery and its branches toward the TCL and the location of the median nerve were determined in 24 fresh cadaver hands perfused with a silicone compound. The ulnar artery coursed from 7 mm ulnar to 2 mm radial to the hook of hamate. The average distance between the superficial palmar arch and the distal margin of the TCL was 12 mm as measured along the flexor tendon of the ring finger. The location of the median nerve extended an average of 11 mm radial to the hook of hamate. A small arterial branch (average diameter, 0.7 mm) from the ulnar artery ran transversely just over the TCL in 6 of the 24 specimens. This branch was consistently located within 15 mm proximal to the TCL distal margin. These and other microscopic observations indicated that transecting the ligament at approximately 5 mm radial to the radial margin of the hook of hamate may minimize postoperative bleeding and avoid iatrogenic vascular and neural injury.

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.

Histology of the transverse carpal ligament and flexor tenosynovium was investigated in 166 wrists from 130 patients with idiopathic carpal tunnel syndrome. Nine wrists from 9 controls were used for comparison. In the patients, 73.5% of the ligament and 56.0% of the tenosynovium showed normal histology. In the remaining specimens, the ligament showed mucoid change (17.5%), amyloid deposits (7.8%), inflammation (3.0%), and chondrometaplasia (2.4%), and the tenosynovium showed fibrosis (25.3%), edema (7.2%), inflammation (10.2%), amyloid deposits (8.4%), and vascular hypertrophy (4.8%). The majority of these changes were mild in degree and the pathophysiology did not appear to be meaningful. We conclude that in idiopathic carpal tunnel syndrome, the ligament and tenosynovium often show normal histology and there are no typical or consistent changes with which idiopathic carpal tunnel syndrome can be associated.

An anatomic basis for carpal tunnel syndrome (CTS) has been proposed but not confirmed; both volumetric and area studies have been used to address this issue. The authors have demonstrated that the ratio of the carpal tunnel contents (CTC) to carpal tunnel volume (CTV) provides information regarding the relative free space in the carpal tunnel as compared with canal volume alone. This study was undertaken to determine whether the CTC/CTV ratio was higher for patients with CTS than for normal subjects. Seven asymptomatic volunteers and 7 patients with symptoms of CTS underwent magnetic resonance imaging (MRI) so that the CTC/CTV ratios could be determined. Standard radiographs were analyzed to identify plain radiographic variables that differed between patients with CTS and control subjects, and no differences were found. On MRIs, however, CTC/CTV ratios were noted to be higher for patients with CTS than for matched control subjects.

This study investigates whether the proximal origins of the lumbrical muscles contribute significantly to the etiology of carpal tunnel syndrome. We explored the carpal canals of 128 hands in patients undergoing carpal tunnel release for carpal tunnel syndrome. The origins of the lumbrical muscles were examined at the time of surgery and their relation to the transverse carpal ligament was recorded in all cases. Also, 40 cadaveric hands were dissected to determine the lumbrical muscle origins. In the hands of patients with idiopathic carpal tunnel syndrome, the lumbrical muscle origins were located significantly more proximal in the canal than were the muscles in the cadaveric hands. Younger patients whose jobs required repetitive hand motions had large lumbrical muscles and origins that were more proximal than the lumbricals found in the hands of fresh cadavers.

This study describes the morphologic changes that occur following single incision endoscopic and two-portal subcutaneous carpal tunnel release. Seventeen patients were studied preoperatively and an average of 24 weeks postoperatively. Canal volume, carpal arch width, and median nerve palmar displacement and cross-sectional area were measured by use of multiplanar reformation and three-dimensional reconstruction of magnetic resonance images. Both methods produced a marked increase in canal volume and median nerve cross-sectional area; neither resulted in a significant change in carpal arch width. These data provide a morphologic basis for the belief that endoscopic or subcutaneous carpal tunnel release will produce clinical relief equivalent to open carpal tunnel release.

Ten hands in 10 patients with carpal tunnel syndrome were treated by subcutaneous transverse carpal ligament release using the Universal Subcutaneous Endoscope system. We analyzed the morphologic changes of the carpal canal with magnetic resonance imaging (0.064 T) before and after the operation. The axial plane, which includes the beak of the trapezium and the hook of the hamate, was selected for analysis. The soft tissue boundaries of the carpal canal were outlined at the plane. The cross-sectional area of the carpal canal was 232 +/- 49 mm2 before surgery and 320 +/- 108 mm2 after surgery. There was a 33% +/- 15% increase of the carpal canal cross-section after transverse carpal ligament release. The transverse carpal ligament became more outwardly convex after the operation. The endoscopic procedure is effective for increasing the cross-sectional area and volume of the carpal canal.

Anatomic relationships of an endoscopic carpal tunnel device to surrounding soft tissue structures along the ring finger and the long-ring interspace axis were investigated in 28 adult cadaver hands. The average distance from the center of the device to the median nerve in the carpal tunnel averaged 3.3 mm in the ring finger axis and 2.5 mm in the long-ring interspace axis. The average distance from the distal edge of the transverse carpal ligament to the superficial palmar arch was 4.8 mm in the ring finger axis and 5.5 mm in the long-ring interspace axis. These and other more subtle anatomic observations indicate the greater safety of using the ring finger axis for endoscopic carpal tunnel release.

Five surgeons performed endoscopic (Dyonics) carpal tunnel releases on 24 fresh cadaver wrists. In 50% of the specimens, transection of the transverse carpal ligament was incomplete. The average amount of incomplete release was 31% (range, 0% to 53%). Three types of incomplete release were noted: (1) release of Guyon's canal release--one, (2) incomplete distal ligament release--five, and (3) incomplete central or superficial release--six. Other technical errors were noted in nine of 24 specimens. There were no nerve lacerations. Endoscopic carpal tunnel release is either a technically demanding procedure, commonly results in incompletely released ligaments, or both. Proper training, followed by practice on several cadaver specimens before its clinical use, is recommended.

We have performed 149 consecutive one-portal and 152 consecutive two-portal endoscopic carpal tunnel release operations. Average time to cessation of preoperative symptoms was 15 days in both the one-portal and two-portal groups. The average time of return to work was 16 days in the one-portal group and 17 days in the two-portal group. The complication rate in the one-portal group was 6%, and in the two-portal group it was 5%. In our opinion, the one-portal release technique is much more difficult and inherently more dangerous than the two-portal technique, and we recommend the latter for endoscopic carpal tunnel release.

To determine the relationship of neurovascular structures to the sites of portal placement and transverse carpal ligament division during two-portal endoscopic carpal tunnel release, a study of 20 fresh cadaver specimens was carried out. Open dissection of the carpal tunnel after endoscopic surgery showed complete ligamentous release in 18 hands (90%). In 10 specimens, the procedure was performed as described by Chow. There was one partial transection of the superficial palmar arch (5%), and five specimens (50%) had complete divisions of the superficial palmar fascia with considerable pressure placed on the ulnar nerve at the wrist. A modified technique was used in 10 specimens in which the proximal incision was made in a more distal location and a distally based ligamentous flap was created. The superficial palmar arch and the distal edge of the transverse carpal ligament were visualized directly before passage of the trocar. No complications were noted with this method.

This article discusses a sensory neural loop on the radial aspect of the median nerve in the palm. The surgeon should be aware of this anomaly when the transverse carpal ligament is divided to approach the structures contained in the carpal canal.

This study investigates the relationship between idiopathic carpal tunnel syndrome and tenosynovial histology, specifically inflammation. Tenosynovial biopsy specimens from 177 wrists were obtained from patients at carpal tunnel release, and a control group of 19 specimens was also obtained. Inflammation was present in only 10% of the patient specimens and was correlated with only one of the clinical and histologic factors studied, i.e., nerve conduction impairment. Edema, observed frequently (85%), was not correlated with inflammation. Vascular sclerosis was also found consistently (98%) and was correlated with patient age and degree of edema. Edema and vascular sclerosis occurred with significantly greater frequency and severity in the specimens of patients than in the control group. Fibrosis (3%) and synovial hyperplasia (1%) were uncommon findings. It is concluded that tenosynovitis is uncommon in patients undergoing surgery for treatment of idiopathic carpal tunnel syndrome.

The histologic lesions in flexor tendon synovium of 21 patients seen initially with idiopathic carpal tunnel syndrome have been studied. The findings were similar in all biopsy specimens and were typical of a connective tissue undergoing degeneration under repeated mechanical stresses.

We describe the morphologic changes that follow division of the transverse carpal ligament in patients with carpal tunnel syndrome. Fifteen hands in 12 patients with carpal tunnel syndrome were studied with magnetic resonance imaging before operation and for 6 weeks after operation. Eight hands were studied at 8 months after operation. Carpal arch width, anterior displacement of the carpal canal contents, and carpal canal volume were measured by use of multiplanar reformation and three-dimensional reconstruction of magnetic resonance images. There was a 24.2 +/- 11.6% increase in carpal canal volume 6 weeks after carpal tunnel release (p less than 0.001). This difference persisted at 8-month follow-up. There was an anterior displacement of carpal canal contents 3.5 +/- 1.9 mm from its original position 6 weeks after operation (p less than 0.001). This palmar displacement persisted at the 8-month follow-up. There was no statistically significant increase in carpal arch width 8 months after carpal tunnel release. We believe that division of the transverse carpal ligament restores median nerve function by increasing the volume of the carpal canal. This volumetric increase results from an anterior displacement of the newly formed transverse carpal ligament and not from a widening of the bony carpal arch.

Carpal tunnel compression and its surgical release has been well described. Motor branch anomalies of the median nerve have also been documented in the literature. Independent recurrent motor branch compression of the median nerve appears to exist in the presence of carpal tunnel symptomatology or as an independent entity. Eight presentations of concomitant or independent compression of the recurrent motor branch of the median nerve have been reviewed. These cases can be subdivided into cases presenting with or without carpal tunnel symptomatology, as well as into two types of independent compression patterns: the first being a direct fascial penetration and entrapment and the second being an acute angulation of the recurrent branch with apparent impingement by the transverse carpal retinaculum. Attention should be directed to the inspection and decompression of the motor branch of the median nerve in those cases that present thenar muscle pathology either clinically or electrodiagnostically.

We treated 20 cases of carpal tunnel syndrome is 12 patients who were undergoing hemodialysis therapy for chronic renal failure. In all patients the arm involved had been used for a fistula. There was no correlation with the renal diagnosis and the duration of hemodialysis therapy. The cause of the syndrome has been debated; however, one factor does not give rise to symptoms of carpal tunnel syndrome. All of the factors discussed in this article, acting in concert, may be causes of carpal tunnel compression. Surgical intervention successfully relieved all symptoms.

Among the large group of carpal tunnel syndromes, it is possible to distinguish two distinct entities, which are related to a persistent median artery. The first is associated with thrombosis, which causes a sudden onset of pain and paresthesia, often severe, while the second is associated with a normal median artery. In the latter case, symptoms predominate during work, and the physical signs are inconsistent. For both entities, the patients are fairly young, with a mean age of 33.6 years. Resection of the artery is recommended after ensuring an adequate arterial supply to the fingers.