Hovius, Steven E.R.

Background: Processed nerve allografts are a promising alternative to nerve autografts, providing an unlimited, readily available supply and avoiding donor-site morbidity and the need for immunosuppression. Currently, clinically available nerve allografts do not provide satisfactory results for motor reconstruction. This study evaluated motor recovery after reconstruction of a long nerve gap using a processed nerve allograft and the influence of storage techniques. Methods: Nerve allografts were decellularized using elastase and detergents and stored at either 4° or −80°C. In 36 New Zealand White rabbits, a 3-cm peroneal nerve gap was repaired with either an autograft (group 1, control) or a cold-stored (group 2) or frozen-stored (group 3) processed nerve allograft. Nerve recovery was evaluated using longitudinal ultrasound measurements, electrophysiology (compound muscle action potentials), isometric tetanic force, wet muscle weight, and histomorphometry after 24 weeks. Results: Longitudinal ultrasound measurements showed that the cold-stored allograft provided earlier regeneration than the frozen-stored allograft. Furthermore, ultrasound showed significantly inferior recovery in group 3 than in both other groups (p < 0.05). Muscle weight and isometric tetanic force showed similar outcomes in the autograft and cold-stored allograft groups [p = 0.096 (muscle weight) and p = 0.286 (isometric tetanic force)], and confirmed the inferiority of the frozen-stored allograft to the autograft [p < 0.01 (muscle weight) and p = 0.02 (isometric tetanic force)]. Conclusions: Frozen storage of the nerve allograft significantly impairs functional recovery and should be avoided. The cold-stored optimized nerve allograft yields functional recovery similar to the gold standard autograft in the reconstruction of a 3-cm motor nerve defect. Future studies should focus on further improvement of the nerve allograft.

Background: In hand surgery, and specifically carpal tunnel syndrome, it is currently unknown whether experiences with health care influence surgical outcome. To investigate whether there is an association between patient-reported experience measures and symptom relief, data were gathered using a cohort of patients undergoing surgical treatment for carpal tunnel syndrome. Methods: Patient-reported experience measures and patient-reported outcome measures were registered in a national database of 16 hand surgery practices. The experience measure data were gathered at 3 months after surgery and included six subscales on different health care delivery aspects (e.g., provided information, communication, facility, operative care). The outcome measure data were acquired before and 3 months after surgery with the Boston Carpal Tunnel Assessment Questionnaire. The association was tested using linear regression analyses. Results: A total of 1607 patients were included in the analysis. The experience measure scores were good to excellent, with a median value between 8.0 and 8.5 on a 10-point scale. Regression analyses showed a significant (p < 0.001) association with the Boston Carpal Tunnel Assessment Questionnaire for all individual patient-reported experience measure subscales. The greatest effects were found in physician communication and treatment information. Patient-reported experience measures accounted for more than 5 percent of the explained variance, with patient characteristics explaining an approximately additional 3 percent. Conclusions: In this large data set of carpal tunnel syndrome patients who underwent surgical release, a significant impact of health care experiences on self-reported clinical outcome was found. This is relevant information, not only for directing care providers in improving health care experiences as a quality-of–health care measure but now also potentially to achieve better clinical outcome. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Background: Elbow flexion after upper brachial plexus injury may be restored by a nerve transfer from the ulnar nerve to the biceps motor branch with an optional nerve transfer from the median nerve to the brachialis motor branch (single and double fascicular nerve transfer). This meta-analysis assesses the effectiveness of both techniques and the added value of additional reinnervation of the brachialis muscle. Methods: Comprehensive searches were performed identifying studies concerning restoration of elbow flexion through single and double fascicular nerve transfers. Only C5 to C6 lesion patients were included in quantitative analysis to prevent confounding by indication. Primary outcome was the proportion of patients reaching British Medical Research Council elbow flexion grade 3 or greater. Meta-analysis was performed with random effects models. Results: Thirty-five studies were included (n = 688). In quantitative analysis, 29 studies were included (n = 341). After single fascicular nerve transfer, 190 of 207 patients reached Medical Research Council grade 3 or higher (random effects model, 95.6 percent; 95 percent CI, 92.9 to 98.2 percent); and after double fascicular nerve transfer, 128 of 134 patients reached grade 3 or higher (random effects model, 97.5 percent; 95 percent CI, 95.0 to 100 percent; p = 0.301). Significantly more double nerve transfer patients reached grade 4 or greater if preoperative delay was 6 months or less (84 of 101 versus 49 of 51; p = 0.035). Conclusions: Additional reinnervation of the brachialis muscle did not result in significantly more patients reaching Medical Research Council grade 3 or higher for elbow flexion. Double fascicular nerve transfer may result in more patients reaching grade 4 or higher in patients with a preoperative delay less than 6 months. The median nerve may be preserved or used for another nerve transfer without substantially impairing elbow flexion restoration.

AbstractBackgroundA bridging nerve autograft is the gold standard for the repair of segmental nerve injury that cannot be repaired directly. However, limited availability and donor site morbidity remain major disadvantages of autografts. Here, a nerve allograft decellularized with elastase was compared with an autograft regarding functional motor outcome in a rat sciatic segmental nerve defect model. Furthermore, the effect of storage on this allograft was studied.MethodsSixty‐six Lewis rats (250–300 g) underwent a 10‐mm sciatic nerve reconstruction using either a cold‐ (n = 22) or frozen‐stored (n = 22) decellularized nerve allograft or an autograft (n = 22). Sprague–Dawley rats (300–350 g) served as full major histocompatibility complex‐mismatched donors. Functional motor outcome was evaluated after 12 and 16 weeks. Ankle angle, compound muscle action potential (CMAP), isometric tetanic force, wet muscle weight, and histomorphometry were tested bilaterally.ResultsFor CMAP and isometric tetanic force, no significant differences were observed between groups. In contrast, for ankle angle, histomorphometry and muscle weight, the cold‐stored allograft performed comparable to the autograft, while the frozen‐stored allograft performed significantly inferior to the autograft. At week 16, ankle angle was 88.0 ± 3.1% in the cold‐stored group, 77.4 ± 3.6% in the frozen‐stored group, and 74.1 ± 3.1% in the autograft group (P < .001); At week 16, the muscle weight showed a recovery up to 71.1 ± 4.8% in the autograft group, 67.0 ± 6.6% in the cold‐stored group, and 64.7 ± 3.7% in the frozen‐stored group (P < .05).ConclusionsA nerve allograft decellularized with elastase, if stored under the right conditions, results in comparable functional motor outcomes as the gold standard, the autograft.

ABSTRACTDynamics of structures within the carpal tunnel may alter in carpal tunnel syndrome (CTS) due to fibrotic changes and increased carpal tunnel pressure. Ultrasound can visualize these potential changes, making ultrasound potentially an accurate diagnostic tool. To study this, we imaged the carpal tunnel of 113 patients and 42 controls. CTS severity was classified according to validated clinical and nerve conduction study (NCS) classifications. Transversal and longitudinal displacement and shape (changes) were calculated for the median nerve, tendons and surrounding tissue. To predict diagnostic value binary logistic regression modeling was applied. Reduced longitudinal nerve displacement (p≤ 0.019), increased nerve cross‐sectional area (p≤ 0.006) and perimeter (p≤ 0.007), and a trend of relatively changed tendon displacements were seen in patients. Changes were more convincing when CTS was classified as more severe. Binary logistic modeling to diagnose CTS using ultrasound showed a sensitivity of 70–71% and specificity of 80–84%. In conclusion, CTS patients have altered dynamics of structures within the carpal tunnel. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1332–1340, 2015.