Citations

Background: Restoring touch perception for individuals with upper extremity limb loss is an ambitious task. It is important to understand how persons with upper limb loss think this would be best achieved. Methods: An anonymous online survey was developed to obtain data from prosthetic users. Participants ranked the perceived acceptability and effectiveness of noninvasive sensory feedback to areas of intact sensation not typically involved in sensory feedback (i.e., the arm). The focus was on 4 main types of haptic information—object contact, proprioception, surface texture, and grasp force—as well as how best to convey those senses with various stimuli. The users were asked to grade themselves in certain tasks and then analyze which tasks would be improved with sensory feedback. Associations were explored between demographic characteristics and interest in sensory feedback. Results: Nationally, prostheses providers sent more than 2000 email invitations to the online survey and received 142 unique responses. Responses indicated interest in sensory feedback through prosthetic limbs by individuals with upper limb loss. The most popular pairing of haptic information with sensory substitution was grasp force paired with gentle vibration. Tasks that most persons taking the survey agreed would benefit from sensory feedback were zipping a jacket, tying shoes, buttoning a shirt, and using a cup. No difference was observed in interest between sex and employment status, but a significant decrease (P = .004) was seen in interest among participants with more years of prosthetic use. Discussion: The results from this national survey of upper extremity prosthetic users can be used to help guide the development of noninvasive sensory feedback options.

Background: Radioscapholunate (RSL) fusion is performed for painful radiocarpal arthritis that is typically posttraumatic or inflammatory in nature. The purpose of this study was to determine whether patients with inflammatory conditions undergoing RSL fusion had comparable outcomes as those with posttraumatic arthritis and to determine factors impacting union. Methods: This was a retrospective review of all RSL fusions over a 25-year period. Demographic information, wrist range of motion, postoperative complications, and surgical technique, including presence or absence of resection of distal scaphoid pole, data were collected. Radiographs were examined for evidence of healing of the RSL fusion site as well as development of midcarpal arthritis. Results: Fifty-six patients underwent RSL fusion. Eight patients required revision of radiocarpal arthrodesis for painful nonunion. The fusion rate was 85.7%, and median 25 th to 75th percentile (time to healing was 4.0 3.2-5.2) months. There were no differences in time to or rate of union by inflammatory arthropathy status. Grip strength increased significantly and pain decreased significantly with surgery. Union rate was 90% with the use of K-wires, screws, or staples, which was significantly greater than plates, fusion cups, or multiple implant types. The use of autologous bone graft significantly decreased the rate of nonunion and significantly decreased time to union by 3 months compared to allograft alone. Extension was significantly improved with scaphoid distal pole resection versus without distal scaphoid pole resection. Conclusions: Radioscapholunate (RSL) fusion is an effective treatment for radiocarpal arthritis but has high nonunion rates. Fixation with K-wires, screws, or staples and use of autograft confers improved union rate.

Transcutaneous (TSS) and epidural spinal stimulation (ESS) are electrophysiological techniques that have been used to investigate the interactions between exogenous electrical stimuli and spinal sensorimotor networks that integrate descending motor signals with afferent inputs from the periphery during motor tasks such as standing and stepping. Recently, pilot-phase clinical trials using ESS and TSS have demonstrated restoration of motor functions that were previously lost due to spinal cord injury (SCI). However, the spinal network interactions that occur in response to TSS or ESS pulses with spared descending connections across the site of SCI have yet to be characterized. Therefore, we examined the effects of delivering TSS or ESS pulses to the lumbosacral spinal cord in nine individuals with chronic SCI. During low-frequency stimulation, participants were instructed to relax or attempt maximum voluntary contraction to perform full leg flexion while supine. We observed similar lower-extremity neuromusculature activation during TSS and ESS when performed in the same participants while instructed to relax. Interestingly, when participants were instructed to attempt lower-extremity muscle contractions, both TSS- and ESS-evoked motor responses were significantly inhibited across all muscles. Participants with clinically complete SCI tested with ESS and participants with clinically incomplete SCI tested with TSS demonstrated greater ability to modulate evoked responses than participants with motor complete SCI tested with TSS, although this was not statistically significant due to a low number of subjects in each subgroup. These results suggest that descending commands combined with spinal stimulation may increase activity of inhibitory interneuronal circuitry within spinal sensorimotor networks in individuals with SCI, which may be relevant in the context of regaining functional motor outcomes.

Arm use in manual wheelchair (MWC) users is characterized by a combination of overuse and a sedentary lifestyle. This study aimed to describe the percentage of daily time MWC users and able-bodied individuals spend in each arm use intensity level utilizing accelerometers. Arm use intensity levels of the upper arms were defined as stationary, low, mid, and high from the signal magnitude area (SMA) of the segment accelerations based on in-lab MWC activities performed by eight MWC users. Accelerometry data were collected in the free-living environments from forty MWC users and 40 sex- and age-matched able-bodied individuals. The SMA intensity levels were applied to the free-living data and the percentage of time spent in each level was calculated. The SMA intensity levels were defined as, stationary: ≤0.67 g, low: 0.671–3.27 g, mid: 3.27–5.87 g, and high: >5.871 g. The dominant arm of both MWC users and able-bodied individuals was stationary for most of the day and less than one percent of the day was spent in high intensity arm activities. Increased MWC user age correlated with increased stationary arm time (R = 0.368, p = 0.019). Five and eight days of data are needed from MWC users and able-bodied individuals, respectively, to achieve reliable representation of their daily arm use intensities.

Epidural electrical stimulation (EES) of the spinal cord has been shown to restore function after spinal cord injury (SCI). Characterization of EES-evoked motor responses has provided a basic understanding of spinal sensorimotor network activity related to EES-enabled motor activity of the lower extremities. However, the use of EES-evoked motor responses to guide EES system implantation over the spinal cord and their relation to post-operative EES-enabled function in humans with chronic paralysis attributed to SCI has yet to be described. Herein, we describe the surgical and intraoperative electrophysiological approach used, followed by initial EES-enabled results observed in 2 human subjects with motor complete paralysis who were enrolled in a clinical trial investigating the use of EES to enable motor functions after SCI. The 16-contact electrode array was initially positioned under fluoroscopic guidance. Then, EES-evoked motor responses were recorded from select leg muscles and displayed in real time to determine electrode array proximity to spinal cord regions associated with motor activity of the lower extremities. Acceptable array positioning was determined based on achievement of selective proximal or distal leg muscle activity, as well as bilateral muscle activation. Motor response latencies were not significantly different between intraoperative recordings and post-operative recordings, indicating that array positioning remained stable. Additionally, EES enabled intentional control of step-like activity in both subjects within the first 5 days of testing. These results suggest that the use of EES-evoked motor responses may guide intraoperative positioning of epidural electrodes to target spinal cord circuitry to enable motor functions after SCI.

Purpose The purpose of this cadaveric study was to compare standard and modified coracoid transfer procedures, bicortical and tricortical iliac crest autografts, and tibial plafond and glenoid allografts with respect to glenoid surface curvature restoration. Methods Computed tomography scans of 8 cadaveric shoulders were acquired in 9 conditions: (1) intact, (2) 25% width defect, (3) classic Latarjet, (4) modified congruent‐arc Latarjet, (5) tricortical iliac crest inner table, (6) outer table, (7) bicortical iliac crest, (8) distal tibia, and (9) glenoid allograft. Outcome measures included articular surface area, width, depth, axial and coronal radius of curvature, and subchondral articular step‐off, analyzed in bone and soft‐tissue window. Results Reconstruction of the articular surface area was optimal with the glenoid allograft (99.4%), classic Latarjet (97.4%), and iliac crest bicortical graft (93.2%). Depth was best restored by the congruent‐arc Latarjet (101.0%), tibial (98.9%), and glenoid (95.3%) allografts. Axial curvature was closely matched by the glenoid allograft (97.5%), classic Latarjet (108.7%), and iliac bicortical graft (91.2%). Coronal curvature was most accurately restored by the glenoid allograft (102.6%), the tibial allograft (115.0%), and the classic Latarjet (55.9%). The articular step‐off was smallest using the glenoid allograft. Conclusions Overall, glenoid allografts most accurately restored articular geometry. Alternative grafts provided restoration of some parameters but not others. Classic Latarjet performed well in axial and coronal curvature on average but exhibited large variability. Tibial allograft produced the poorest results in axial curvature, despite excellent coronal curvature reconstruction. The congruent‐arc Latarjet did not restore the axial curvature accurately and overcorrected coronal curvature. Graft geometry must be weighed against availability, morbidity, and the role of additional stabilizers. Clinical Relevance Accurate graft morphology may help prevent postoperative osteoarthritis. Grafts differ significantly regarding geometric parameters. The findings of this study will help surgeons select the most appropriate graft for glenoid reconstruction.