Erythropoietin accelerates functional recovery after moderate sciatic nerve crush injury.

INTRODUCTION: Erythropoietin (EPO) has been identified as a neuroregenerative agent. We hypothesize that it may accelerate recovery after crush injury and may vary with crush severity. METHODS: Mice were randomized to mild, moderate, or severe crush of the sciatic nerve and were treated with EPO or vehicle control after injury. The sciatic function index (SFI) was monitored over the first week. Microstructural changes were analyzed by immunofluorescence for neurofilament (NF) and myelin (P0 ), and electron microscopy was used to assess ultrastructural changes. RESULTS: In moderate crush injuries, EPO significantly improved SFI at 7 days post-injury, an effect not observed with other severity levels. Increases in the ratio of P0 to NF were observed after EPO treatment in moderate crush injuries. Electron microscopy demonstrated endothelial cell hypertrophy in the EPO group. CONCLUSIONS: EPO accelerates recovery in moderately crushed nerves, which may be through effects on myelination and vascularization. Injury severity may influence the efficacy of EPO. Muscle Nerve 56: 143-151, 2017.

Patient-Reported Outcomes Following Sectioning of the Filum Terminale for Treatment of Tethered Cord Syndrome Associated With Ehlers-Danlos Syndrome.

Introduction Tethered cord syndrome (TCS) was first reported as a potential complication of Ehlers-Danlos Syndrome in 2009. However, there have been few publications on the subject since that time, and optimal treatment of TCS in the setting of the hypermobile Ehlers-Danlos Syndrome (hEDS) population remains unknown. The purpose of this study was to determine the safety and efficacy of surgical release of the filum terminale (FT) for the treatment of TCS in this patient population. Methods We performed a retrospective chart review of consecutive hEDS patients with TCS who were treated with surgical release after providing informed surgical consent over a 4.5-year period by a single neurosurgeon. Eighty-four patients were identified and asked to complete surveys with items regarding pre and postoperative symptoms, pain levels, and satisfaction. Results Thirty patients with a mean age of 30.8 ± 11.9 years, all female, were included. Low back pain was significantly improved across the entire cohort. For patients with both pre and postoperative data available, the distance they were able to walk also improved significantly. The majority of patients were "highly satisfied" with surgery (66%), followed by 21% "satisfied", 10% "neutral", and one patient who was "dissatisfied". One patient required repair of a dural leak one week postoperatively, and no other complications were noted. Conclusions Surgical release of the FT for TCS in patients with hEDS was safe and effective in this cohort. For most patients, there was a significant improvement in low back pain, urinary symptoms, and ability to ambulate distance. The majority of respondents reported subjective satisfaction with this operation. A further prospective study is warranted.

Correlation of malrotation deformity in distal radius fractures with radiographic analysis: cadaveric study.

PURPOSE: The radiographic parameters commonly used for evaluating distal radius fractures are radial length, palmar tilt, radial inclination, and articular congruity. Rotation of the distal fragment is not routinely evaluated after distal radius fractures. The purpose of this study was to define the appearance of distal fragment malrotation on conventional radiographs and to correlate varying degrees of malrotation with the corresponding radiographic findings. METHODS: Six distal radiuses from embalmed cadavers were cut and stabilized in 10 degrees, 20 degrees, and 30 degrees of pronated malrotation. Posteroanterior, lateral, and oblique (45 degrees pronated view) radiographs were taken and radiographic measurements were made of radial length, palmar tilt, radial inclination, and rotation. RESULTS: With malrotation, the visible cortical width of the distal fragment mismatched the visible cortical width of the proximal fragment. This was most evident on the oblique view (p < .05) and measured 2.2 mm for 10 degrees of rotation (standard deviation [SD] 0.6), 3.4 mm for 20 degrees of rotation (SD 0.8), and 5.3 mm for 30 degrees of rotation (SD 2.2). CONCLUSIONS: The radiographic parameter of rotation should be considered when evaluating distal radius fracture reduction. Malrotation is best seen on a 45 degrees oblique pronated radiographic view as a mismatch of the cortical width of the distal fragment compared with the cortical width of the proximal fragment. In the absence of radial shortening, a 5.3-mm mismatch is associated with 30 degrees of malrotation and is the upper limit of acceptability.

A biomechanical study of extensor tendon repair methods: introduction to the running-interlocking horizontal mattress extensor tendon repair technique.

PURPOSE: Extensor tendon injuries are common; however, relatively few studies have evaluated extensor tendon repair methods. The purpose of this study was to investigate the properties of the running-interlocking horizontal mattress repair method with regard to tendon shortening, stiffness, strength, and time needed to perform the repair, compared with the modified Bunnell method and the augmented Becker method. METHODS: Twenty-four extensor tendons from 8 fresh-frozen cadaveric hands were harvested from zone 6. The harvested tendons were randomly assigned into 1 of 3 repair groups: augmented Becker, modified Bunnell, and running-interlocking horizontal mattress repair methods. The running-interlocking horizontal mattress repair combines a running suture with an interlocking horizontal mattress suture. Each repaired tendon was measured for length before and after repair and tested for stiffness, ultimate load to failure, and time required to perform the repair. RESULTS: The running-interlocking horizontal mattress repair was significantly stiffer (8,506 N/m) than the augmented Becker (5,971 N/m) and the modified Bunnell (6,719 N/m) repairs. The running-interlocking horizontal mattress repair resulted in significantly less shortening (1.7 mm) than the augmented Becker (6.2 mm) and modified Bunnell (6.3 mm) repairs. The running-interlocking horizontal mattress repair took significantly less time to perform without a significant difference in the ultimate load to failure (running-interlocking horizontal mattress repair, 51 N; augmented Becker, 53 N; modified Bunnell, 48 N). CONCLUSIONS: The running-interlocking horizontal mattress repair is significantly stiffer and faster to perform than either the augmented Becker or the modified Bunnell repairs, and it results in less shortening than either of these methods. The running-interlocking horizontal mattress repair should be strong enough to withstand some early motion.

The effects of core suture purchase on the biomechanical characteristics of a multistrand locking flexor tendon repair: a cadaveric study.

PURPOSE: To determine the effects of suture purchase on work of flexion (WOF), 2-mm gap force, and load to failure on the combination cross-locked cruciate-interlocking horizontal mattress (CLC-IHM) flexor tendon repair in zone II. METHODS: A total of 33 fresh-frozen cadaveric fingers were mounted in a custom jig, and the flexor digitorum profundus of each finger was fixed to the mobile arm of a tensile strength machine. Initial measurements of WOF were obtained. Each tendon was repaired with the CLC core suture, randomly assigned to placement of 3, 5, 7 or 10 mm from the cut edge of the tendon, and completed with the IHM circumferential suture. After the repair was completed, measurements of WOF were repeated. Each finger was cycled 1000 times. After each 250 cycles, gapping was recorded, and WOF was measured again. Change in WOF (WOF after repair - WOF of intact tendon) was calculated. Tendons were then dissected from the fingers and linearly tested for 2-mm gap force and ultimate load to failure. RESULTS: The group repaired at 10 mm had the lowest percent increase in WOF (5.2%), the highest 2-mm gap force (89.8 N), and the highest ultimate load to failure (111.5 N). The group repaired at 3 mm had the highest percent increase in WOF (22.1%), the lowest 2-mm gap force (54.6 N), and the lowest ultimate load to failure (84.6 N). CONCLUSIONS: A 10-mm suture purchase is the recommended distance for optimal performance for the CLC-IHM combination repair method. This method with a 10-mm suture purchase has a low increase in WOF, high strength, and high resistance to gapping, and it should be strong enough to tolerate early motion.

Shoulder arthritis secondary to rotator cuff tear: A reproducible murine model and histopathologic scoring system.

Untreated rotator cuff tears can progress to a distinct form of shoulder arthritis, and the mechanism of this progression is poorly understood. Biomechanical, molecular and genetic factors may be at play, and a reliable animal model is needed to enable further research. The purpose of this study was to create a reproducible model of posttraumatic shoulder arthritis in the mouse, and to develop a scoring system for this model to enable future research on interventions, the role of various gene products, and the development of therapies to alter the natural course of the disease. Forty-five mice underwent operative ligation of the rotator cuff tendons and were followed for 45 weeks following surgery, with free cage activity post-operatively. Mice were sacrificed at various intervals from 2 to 45 weeks post-injury and histopathologic scoring was developed and tested by blinded reviewers using both quantitative computational analysis of coronal sections of the shoulder joint and semi-quantitative grading. The scoring system revealed a progressive, time-dependent set of tissue changes in the shoulder joint with features similar to human cuff tear arthropathy including acetabularization of the acromion and femoralization of the humeral head. This model establishes that osteoarthritis of the shoulder is distinct from osteoarthritis of the knee or hip, with different stages of degeneration and unique histopathologic features. Using the novel grading procedure and quantitative assessments presented here, future research using this model will enable investigators to test established and novel therapies and evaluate the role of inflammatory factors and gene products in shoulder arthritis. This study provides a reproducible mouse model of shoulder arthritis following isolated injury to the rotator cuff which elucidates characteristics of cuff tear arthropathy and provides a scoring system and venue for future research. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:506-514, 2017.

Network injury to pulvinar with neonatal arterial ischemic stroke.

The purpose of this study is to establish that newborn stroke involving extensive parts of cerebral cortex immediately leads to secondary network injury in pulvinar. Seven term infants with cortical stroke presented with hypersignal in pulvinar on DWI. Stroke types included: complete MCA stroke (n=4); PCA stroke, ICA stroke and multiple artery stroke (1 each). Age range at scanning was between day 2 and 6 after birth (except for 1 infant scanned within 7 days of acute presentation during ECMO). ADC values in secondarily injured pulvinar were significantly higher than in the area with primary (sub)cortical injury (all patients scanned with identical MR image acquisition). In the absence of asphyxia and because pulvinar is outside of the primary area of infarction, we conclude that there are suggestions from imaging for acute secondary injury to pulvinar following primary damage of their cortical targets and/or connecting axons. Acute secondary injury is probably due to excitotoxicity and deafferentiation. The relevance of network injury for prognosis and the impact of early treatment on it have yet to be studied, in stroke but also in other acute perinatal brain disorders.