Edward Diao

Single-portal endoscopic carpal tunnel release compared with open release : a prospective, randomized trial.

Background: Carpal tunnel syndrome is a common condition causing hand pain and numbness. Endoscopic carpal tunnel release has been demonstrated to reduce recovery time, although previous studies have raised concerns about an increased rate of complications. The purpose of this prospective, randomized study was to compare open carpal tunnel release with single-portal endoscopic carpal tunnel release. Methods: A prospective, randomized, multicenter center study was performed on 192 hands in 147 patients. The open method was performed in ninety-five hands in seventy-two patients, and the endoscopic method was performed in ninety-seven hands in seventy-five patients. All of the patients had clinical signs or symptoms and electrodiagnostic findings consistent with carpal tunnel syndrome and had not responded to, or had refused, nonoperative management. Follow-up evaluations with use of validated outcome instruments and quantitative measurements of grip strength, pinch strength, and hand dexterity were performed at two, four, eight, twelve, twenty-six, and fifty-two weeks after the surgery. Complications were identified. The cost of the procedures and the time until return to work were recorded and compared between the groups. Results: During the first three months after surgery, the patients treated with the endoscopic method had better Carpal Tunnel Syndrome Symptom Severity Scores, better Carpal Tunnel Syndrome Functional Status Scores, and better subjective satisfaction scores. During the first three months after surgery, they also had significantly (p < 0.05) greater grip strength, pinch strength, and hand dexterity. The open technique resulted in greater scar tenderness during the first three months after surgery as well as a longer time until the patients could return to work (median, thirty-eight days compared with eighteen days after the endoscopic release). No technical problems with respect to nerve, tendon, or artery injuries were noted in either group. There was no significant difference in the rate of complications or the cost of surgery between the two groups. Conclusion: Good clinical outcomes and patient satisfaction are achieved more quickly when the endoscopic method of carpal tunnel release is used. Single-portal endoscopic surgery is a safe and effective method of treating carpal tunnel syndrome.

Mallet finger: results of early versus delayed closed treatment.

The efficacy of continuous splinting was retrospectively compared in two populations of 40 patients with soft tissue and bony mallet finger whose treatment was initiated within 2 weeks after injury (early) or more than 4 weeks after trauma (delayed). Splint treatment was successful in restoring active extension (with no more than 10 degrees extensor lag) in 17 of 21 patients in the early group and 15 of 19 patients in the delayed group. Neither the presence or absence of dorsal lip fracture less than one third of the articular surface of the distal phalanx nor the type of splint used affected the final outcome. Splinting was as effective in the delayed treatment population as it was in the early treatment population.

Zone-II Flexor Tendon Repair: A Randomized Prospective Trial of Active Place-and-Hold Therapy Compared with Passive Motion Therapy

BACKGROUND In order to improve digit motion after zone-II flexor tendon repair, rehabilitation programs have promoted either passive motion or active motion therapy. To our knowledge, no prospective randomized trial has compared the two techniques. Our objective was to compare the results of patients treated with an active therapy program and those treated with a passive motion protocol following zone-II flexor tendon repair. METHODS Between January 1996 and December 2002, 103 patients (119 digits) with zone-II flexor tendon repairs were randomized to either early active motion with place and hold or a passive motion protocol. Range of motion was measured at six, twelve, twenty-six, and fifty-two weeks following repair. Dexterity tests were performed, and the Disabilities of the Arm, Shoulder, and Hand (DASH) outcome questionnaire and a satisfaction score were completed at fifty-two weeks by ninety-three patients (106 injured digits). RESULTS At all time points, patients treated with the active motion program had greater interphalangeal joint motion. At the time of the final follow-up, the interphalangeal joint motion in the active place-and-hold group was a mean (and standard deviation) of 156 degrees +/- 25 degrees compared with 128 degrees +/- 22 degrees (p < 0.05) in the passive motion group. The active motion group had both significantly smaller flexion contractures and greater satisfaction scores (p < 0.05). We could identify no difference between the groups in terms of the DASH scores or dexterity tests. When the groups were stratified, those who were smokers or had a concomitant nerve injury or multiple digit injuries had less range of motion, larger flexion contractures, and decreased satisfaction scores compared with patients without these comorbidities. Treatment by a certified hand therapist resulted in better range of motion with smaller flexion contractures. Two digits in each group had tendon ruptures following repair. CONCLUSIONS Active motion therapy provides greater active finger motion than passive motion therapy after zone-II flexor tendon repair without increasing the risk of tendon rupture. Concomitant nerve injuries, multiple digit injuries, and a history of smoking negatively impact the final outcome of tendon repairs.

Tensions of the flexor digitorum superficialis are higher than a current model predicts

Existing isometric force models can be used to predict tension in the finger flexor tendon, however, they assume a specific distribution of forces across the tendons of the fingers. These assumptions have not been validated or explored by experimental methods. To determine if the force distributions repeatably follow one pattern the in vivo tension of the flexor digitorum superficialis (FDS) tendon of the long finger was measured in nine patients undergoing open carpal tunnel release surgery. Following the release, a tendon force transducer (Dennerlein et al. 1997 J. Biomechanics 30(4), 395-397) was mounted onto the FDS of the long finger. Tension in the tendon, contact force at the fingertip, and finger posture were recorded while the patient gradually increased the force applied by the fingertip from 0 to 10 N and then monotonically reduced it to 0 N. The average ratio of the tendon tension to the fingertip contact force ranged from 1.7 to 5.8 (mean = 3.3, s.d. = 1.4) for the nine subjects. These ratios are larger than ratios predicted by current isometric tendon force models (mean = 1.2, s. d. = 0.4). Subjects who used a pulp pinch posture (hyper-extended distal interphalangeal joint (DIP)) showed a significantly (p = 0.02) larger ratio (mean = 4.4, s.d. = 1.5) than the five subjects who flexed the DIP joint in a tip pinch posture (mean = 2.4, s.d. = 0.6). A new DIP constraint model, which selects different force distribution based on DIP joint posture, predicts force ratios that correlate well with the measured ratios (r2 = 0.85).

Morphologic changes following endoscopic and two-portal subcutaneous carpal tunnel release.

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.

Engineering Bi-Layer Nanofibrous Conduits for Peripheral Nerve Regeneration

Trauma injuries often cause peripheral nerve damage and disability. A goal in neural tissue engineering is to develop synthetic nerve conduits for peripheral nerve regeneration having therapeutic efficacy comparable to that of autografts. Nanofibrous conduits with aligned nanofibers have been shown to promote nerve regeneration, but current fabrication methods rely on rolling a fibrous sheet into the shape of a conduit, which results in a graft with inconsistent size and a discontinuous joint or seam. In addition, the long-term effects of nanofibrous nerve conduits, in comparison with autografts, are still unknown. Here we developed a novel one-step electrospinning process and, for the first time, fabricated a seamless bi-layer nanofibrous nerve conduit: the luminal layer having longitudinally aligned nanofibers to promote nerve regeneration, and the outer layer having randomly organized nanofibers for mechanical support. Long-term in vivo studies demonstrated that bi-layer aligned nanofibrous nerve conduits were superior to random nanofibrous conduits and had comparable therapeutic effects to autografts for nerve regeneration. In summary, we showed that the engineered nanostructure had a significant impact on neural tissue regeneration in situ. The results from this study will also lead to the scalable fabrication of engineered nanofibrous nerve conduits with designed nanostructure. This technology platform can be combined with drug delivery and cell therapies for tissue engineering.

Pressure changes in Guyon's canal after carpal tunnel release

We measured pressure changes in Guyons canal and the carpal tunnel before and after endoscopic (11 cases) and open (10) carpal tunnel release. We found that release of the flexor retinaculum by endoscopic and open techniques measurably decreased pressure in both the carpal tunnel and Guyons canal. This study provides an explanation for relief of ulnar tunnel syndrome symptoms following carpal tunnel release and may indicate that carpal tunnel release alone may be sufficient to provide symptomatic relief for most patients with carpal and ulnar tunnel syndromes.

Device for zone-II flexor tendon repair. A multicenter, randomized, blinded, clinical trial.

BACKGROUND The stainless-steel Teno Fix tendon-repair device has improved biomechanical characteristics compared with those of suture repair, and it was well tolerated in a canine model. The purpose of this study was to compare the Teno Fix with suture repair in a clinical setting. METHODS Sixty-seven patients with isolated zone-II flexor tendon injury were randomized to be treated with a Teno Fix or a four-stranded cruciate suture repair. There were eighty-five injured digits: thirty-four were treated with the Teno Fix, and fifty-one served as controls. A modified Kleinert rehabilitation technique was employed, with active flexion starting at four weeks postoperatively. Patients were followed for six months by blinded observers who determined the range of motion, Disabilities of the Arm, Shoulder and Hand (DASH) score, pinch and grip strength, and pain score on a verbal scale and assessed swelling and neurologic recovery. Adverse outcomes, including device migration and rupture, were monitored at frequent intervals. RESULTS Nine of the fifty-one suture repairs ruptured, whereas none of the Teno Fix repairs ruptured (p < 0.01). Five of the nine ruptures were caused by resistive motion against medical advice. There were no differences between the two groups in terms of range of motion, DASH score, pinch and grip strength, pain, swelling, or neurologic recovery. The Teno Fix group had slightly slower resolution of pain and swelling compared with the control group. Of the patients who were available for follow-up at six months, sixteen of the twenty-four treated with a Teno Fix repair and nineteen of the twenty-seven treated with a control repair had a good or excellent result. One Teno Fix device migrated and extruded secondary to a wound infection. Of all eighty-five digits that were operated on, four were thought to have tendons of inadequate size to accommodate the device and nine were deemed to have inadequate exposure to allow placement of the anchors. CONCLUSIONS The Teno Fix is safe and effective for flexor tendon repair if the tendon size and exposure are sufficient. Tendon repairs with the Teno Fix have lower rupture rates and similar functional outcomes when compared with conventional repair, particularly in patients who are noncompliant with the rehabilitation protocol.

Comparative mechanical analysis of dorsal versus palmar placement of core suture for flexor tendon repairs

This study was designed to evaluate the effect of core suture placement in the coronal plane on the tensile strength of flexor tendon repairs. We compared the tensile strength of modified Kessler core sutures placed in the palmar versus the dorsal side of matched-lacerated human cadaver flexor digitorum profundus tendons tested in vitro under static loading. We also compared the relative strengths of the dorsal and palmar portions of the flexor digitorum tendons. The mean failure load of a dorsal-side modified Kessler suture was 26.5% greater than that of a palmar-side modified Kessler suture. The mean strength of the dorsal half of the flexor digitorum tendons was 58.3% greater than that of the palmar half of the flexor digitorum tendons. Our data demonstrate that the dorsal tendon can sustain greater loads-to-failure than the palmar tendon. This suggests that there are biomechanical advantages to dorsal as opposed to palmar placement of the core suture in clinical tendon repair.

Partial lacerations of human digital flexor tendons: A biomechanical analysis

The biomechanical properties of human flexor tendons with partial lacerations have not been previously studied. To determine the loss of tensile strength with varying degrees of partial laceration, tensile tests were performed on 2 matched groups of human cadaver flexor tendons: One group had 50% while the other had 75% transverse volar lacerations of the anteroposterior diameter. The mean failure load of the 50%-lacerated tendons was 93% higher than that of the 75%-lacerated tendons. The forces tolerated by the lacerated tendons before failure were also compared to those measured in vivo during physiologic loading. The breaking loads of both 50%- and 75%-lacerated tendons far exceeded the in vivo forces measured in human flexor tendons during unresisted active finger movement (up to 34 N). Further, the breaking loads of 50% lacerations was higher than the in vivo forces during resisted active finger movement (up to 117 N). This study demonstrates that the threshold load levels to rupture of 50% and 75% lacerations are higher than physiologic load levels measured during active motion, suggesting that partial flexor tendon lacerations of up to 75% can withstand in vivo forces associated with active unresisted mobilization of the digital flexor tendon.