Surgical restoration of the upper limb in cervical spinal cord injury patients.

Prior to the 1950s, relatively few patients who suffered a transection of the cervical spinal cord survived their injury. Improved medical care and better coordination have resulted in greater numbers of patients surviving and leaving the hospital. The pioneering work of individual surgeons during the 1960s and 1970s stimulated interest in surgical restoration of upper limb function in tetraplegic patients. Since the publication of Moberg's monograph in 1978, surgical improvement of the upper limbs is regarded as one of the options that should be offered to tetraplegic individuals to improve their function. Patients are classified according to the level of spinal cord injury and the residual motor function (international classification: groups 1-9). Surgical procedures are adapted to the motor level for each group of patients. Indications for these procedures are well standardized, the techniques are well mastered, and predictable results can be expected. New nerve transfer techniques have been developed in recent years; they are currently being evaluated.

Access to surgical upper extremity care for people with tetraplegia: an international perspective.

STUDY DESIGN: Survey. OBJECTIVES: To determine whether upper extremity reconstruction in patients with tetraplegia is underutilized internationally and, if so, what are the barriers to care. SETTING: International-attendees of a meeting in Paris, France. METHODS: One hundred and seventy attendees at the Tetrahand meeting in Paris in 2010 were sent a 13-question survey to determine the access and utilization of upper limb reconstruction in tetraplegic patients in their practice. RESULTS: Respondents ranged the globe including North America, South America, Europe, Asia and Australia. Fifty-nine percent of respondents had been practicing for more than 10 years. Sixty-four percent of respondents felt that at least 25% of people with tetraplegia would be candidates for surgery. Yet the majority of respondents found that <15% of potential patients underwent upper extremity reconstruction. Throughout the world direct patient referral was the main avenue of surgeons meeting patients with peer networking a distant second. Designated as the top three barriers to this care were lack of knowledge of surgical options by patients, lack of desire for surgery and poor referral patterns to appropriate upper extremity surgeons. CONCLUSION: The results of this survey, of a worldwide audience, indicate that many of the same barriers to care exist regardless of the patient's address. This was a preliminary opinion survey and thus the results are subjective. However, these results provide a roadmap to improving access to care by improving patient education and interdisciplinary physician communication.

Biomechanics of the Steindler flexorplasty surgery: a computer simulation study.

PURPOSE: Our goal was to investigate the capacity of a Steindler flexorplasty to restore elbow flexion to persons with C5-C6 brachial plexus palsy. In this procedure the origin of the flexor-pronator mass is moved proximally onto the humeral shaft. We examined how the choice of the proximal attachment site for the flexor-pronator mass affects elbow flexion restoration, especially considering possible side effects including limited wrist and forearm motion owing to passive restraint from stretched muscles. METHODS: A computer model of the upper extremity was used to simulate the biomechanical consequences of various surgical alterations. Unimpaired, preoperative, and postoperative conditions were simulated. Seven possible transfer locations were used to investigate the effects of choice of transfer location. RESULTS: Each transfer site produced a large increase in elbow flexion strength. Transfer to more proximal attachment sites also produced large increases in passive resistance to wrist extension and forearm supination. CONCLUSIONS: To reduce detrimental side effects while achieving clinical goals our theoretical analysis suggests a transfer to the distal limit of the traditional transfer region.

Gene expression of transforming growth factor beta isoforms in interposition nerve grafting.

Scar production and neuroma formation at nerve graft coaptation sites may limit axonal regeneration and impair functional outcome. Transforming growth factor beta (TGF-beta) is a family of growth factors that is involved in scar formation, wound healing, and nerve regeneration. Fifteen adult Sprague-Dawley rats underwent autogenous nerve grafting. The nerve grafts were analyzed by in situ hybridization to determine the temporal and spatial expression of TGF-beta1 and TGF-beta3 messenger RNA (mRNA). The grafted nerves showed increased expression of TGF-beta1 and TGF-beta3 mRNA in the nerve and the surrounding connective tissue during the first postoperative week. These data suggest that modulation of TGF-beta levels in the first postoperative week may be effective in helping to control scar formation and improve nerve regeneration.

Efficacy of an implanted neuroprosthesis for restoring hand grasp in tetraplegia: a multicenter study.

OBJECTIVE: To evaluate an implanted neuroprosthesis that allows tetraplegic users to control grasp and release in 1 hand. DESIGN: Multicenter cohort trial with at least 3 years of follow-up. Function for each participant was compared before and after implantation, and with and without the neuroprosthesis activated. SETTING: Tertiary spinal cord injury (SCI) care centers, 8 in the United States, 1 in the United Kingdom, and 1 in Australia. PARTICIPANTS: Fifty-one tetraplegic adults with C5 or C6 SCIs. INTERVENTION: An implanted neuroprosthetic system, in which electric stimulation of the grasping muscles of 1 arm are controlled by using contralateral shoulder movements, and concurrent tendon transfer surgery. Assessed participants' ability to grasp, move, and release standardized objects; degree of assistance required to perform activities of daily living (ADLs), device usage; and user satisfaction. MAIN OUTCOME MEASURES: Pinch force; grasp and release tests; ADL abilities test and ADL assessment test; and user satisfaction survey. RESULTS: Pinch force was significantly greater with the neuroprosthesis in all available 50 participants, and grasp-release abilities were improved in 49. All tested participants (49/49) were more independent in performing ADLs with the neuroprosthesis than they were without it. Home use of the device for regular function and exercise was reported by over 90% of the participants, and satisfaction with the neuroprosthesis was high. CONCLUSIONS: The grasping ability provided by the neuroprosthesis is substantial and lasting. The neuroprosthesis is safe, well accepted by users, and offers improved independence for a population without comparable alternatives.

Surgeon-patient barrier efficiency monitored with an electronic device in three surgical settings.

Blood-borne viral pathogens are an occupational threat to health care workers (HCWs), particularly those in the operating room. A major risk is posed by accidental penetrating injury, but skin contamination with body fluids from an infected patient, with prolonged intimate cutaneous contact, is a frequent occurrence during surgery, carrying further risk of transdermal infection. We have monitored barrier failure in three surgical settings (microsurgery, orthopedic surgery, general surgery) by means of an electronic surveillance device. A total of 111 surgical procedures were monitored: 67 microsurgeries, 22 orthopedic surgeries, and 22 general surgeries. Of the 278 electronic alarms signaling barrier failure, 44 (15.8%) were associated with glove perforation, 39 of which (88.6%) were not perceived by the operator. In 16 of those, the skin was visibly stained with the patient's blood. Altogether, 76 of the alarms (27.3%) were consequent to contacts caused by soaked gowns/sleeves, and 121 (43.5%) were attributed to hydration of latex porosities; 37 alarms (13.4%) were unexplained false positives. On only one occasion did a surgeon observe blood stains on his hands without a previous alarm; this event was classified as a device failure due to incorrect wiring. Double-gloving offered satisfactory protection against skin contamination during microsurgery but not during orthopedic surgery. The data presented here indicate that electronic monitoring of the surgical barrier enables prompt detection of barrier failure, especially at the level of the gloves, thereby limiting skin contamination with patients' body fluids during surgery.

Activation patterns of the thumb muscles during stable and unstable pinch tasks.

The ability to direct forces between the thumb and fingers is important to secure objects in the hand. We compared the coordination of thumb musculature in key and opposition pinch postures between stable and unstable tasks. The unstable task (producing thumb-tip force wearing a beaded thimble) required well-directed forces; the stable task (producing thumb-tip force against a pinch meter) did not. Fine-wire electromyography of thumb muscles and thumb-tip force magnitudes were recorded. We found no statistical differences in thumb-tip force between postures or stable versus unstable tasks, indicating that the highest magnitudes of force can be accurately directed. Abductor pollicis brevis and extensor pollicis longus were significantly more activated in the unstable tasks, suggesting their importance in directing thumb-tip force. Understanding how pinch forces are directed might influence the choice of muscle-tendon transfers performed to restore function to the severely paralyzed thumb. We introduce a device to quantify the ability to control pinch force magnitude and direction simultaneously.

Improvement of Schwann cell attachment and proliferation on modified hyaluronic acid strands by polylysine.

Hyaluronic acid (HyA) has the intrinsic ability to promote cell proliferation and reduce scar formation. However, the clinical use of HyA has so far been limited because of its water solubility and nonadhesive characteristics. Increasing interest in HyA as a clinically useful biomaterial has prompted our study of altering HyA's physical properties to render it a potential component of nerve grafts. In this study, strands of HyA were cross-linked by glutaraldehyde (Glut), coated with polylysine, and then inoculated with Schwann cells (SCs). Results in vivo and in vitro demonstrated that cross-linked HyA strands were water insoluble and thus less biodegradable. Poly-D-lysine-resurfaced strands showed significant SC attachment of 350-400 cells/mm(2), compared to uncoated controls (0-10 cells/mm(2), p < 0.01). Fibroblast control groups showed an attachment of 40-100 cells/mm(2) on coated strands. Immunostaining for proliferating cells showed SCs as and fibroblasts as +. Cells neither adhered to nor proliferated on the modified HyA strands that were not resurfaced. The results suggest that polylysine promotes SC attachment and proliferation to glutaraldehyde-cross-linked HyA strands, the product being a three-dimensional composite with low solubility that may have potential application in nerve grafts.

Hand and wrist injuries in young athletes.

Successful treatments of musculoskeletal injuries in the pediatric population demand a thorough understanding of the basic anatomy and its biomechanics, and the physiology of growth and development of the immature skeleton. In addition, good treatment outcomes rely on the treating physician being an effective teacher to the young athlete and the patient's parents, coaches, and trainers. At the same time, the physician must be a good student in learning the nature of the patient's sports and each patient's athletic ability and aspirations. Most pediatric hand and wrist injuries can be treated nonoperatively with proper immobilization techniques and activity modification, but cases requiring surgical intervention must be recognized promptly to avoid long-term complications.

Quantification of fingertip force reduction in the forefinger following simulated paralysis of extensor and intrinsic muscles.

Objective estimates of fingertip force reduction following peripheral nerve injuries would assist clinicians in setting realistic expectations for rehabilitating strength of grasp. We quantified the reduction in fingertip force that can be biomechanically attributed to paralysis of the groups of muscles associated with low radial and ulnar palsies. We mounted 11 fresh cadaveric hands (5 right, 6 left) on a frame, placed their forefingers in a functional posture (neutral abduction, 45 degrees of flexion at the metacarpophalangeal and proximal interphalangeal joints, and 10 degrees at the distal interphalangeal joint) and pinned the distal phalanx to a six-axis dynamometer. We pulled on individual tendons with tensions up to 25% of maximal isometric force of their associated muscle and measured fingertip force and torque output. Based on these measurements, we predicted the optimal combination of tendon tensions that maximized palmar force (analogous to tip pinch force, directed perpendicularly from the midpoint of the distal phalanx, in the plane of finger flexion-extension) for three cases: non-paretic (all muscles of forefinger available), low radial palsy (extrinsic extensor muscles unavailable) and low ulnar palsy (intrinsic muscles unavailable). We then applied these combinations of tension to the cadaveric tendons and measured fingertip output. Measured palmar forces were within 2% and 5 degrees of the predicted magnitude and direction, respectively, suggesting tendon tensions superimpose linearly in spite of the complexity of the extensor mechanism. Maximal palmar forces for ulnar and radial palsies were 43 and 85% of non-paretic magnitude, respectively (p<0.05). Thus, the reduction in tip pinch strength seen clinically in low radial palsy may be partly due to loss of the biomechanical contribution of forefinger extrinsic extensor muscles to palmar force. Fingertip forces in low ulnar palsy were 9 degrees further from the desired palmar direction than the non-paretic or low radial palsy cases (p<0.05).

A virtual-reality-based telerehabilitation system with force feedback.

A PC-based orthopedic rehabilitation system was developed for use at home, while allowing remote monitoring from the clinic. The home rehabilitation station has a Pentium II PC with graphics accelerator, a Polhemus tracker, and a multipurpose haptic control interface. This novel interface is used to sample a patient's hand positions and to provide resistive forces using the Rutgers Master II (RMII) glove. A library of virtual rehabilitation routines was developed using WorldToolKit software. At the present time, it consists of three physical therapy exercises (DigiKey, ball, and power putty) and two functional rehabilitation exercises (peg board and ball game). These virtual reality exercises allow automatic and transparent patient data collection into an Oracle database. A remote Pentium II PC is connected with the home-based PC over the Internet and an additional video conferencing connection. The remote computer is running an Oracle server to maintain the patient database, monitor progress, and change the exercise level of difficulty. This allows for patient progress monitoring and repeat evaluations over time. The telerehabilitation system is in clinical trails at Stanford Medical School (CA), with progress being monitored from Rutgers University (NJ). Other haptic interfaces currently under development include devices for elbow and knee rehabilitation connected to the same system.

Polypeptide resurfacing method improves fibroblast's adhesion to hyaluronan strands.

Hyaluronic acid (hyaluronan, HyA) is a matrix component that takes part in cell adhesion and growth in normal and repaired tissues. Since it is soluble in water, HyA has been of limited use in tissue engineering of artificial matrices. Recent studies demonstrate that polypeptides have the twin advantages of reducing solubility of HyA and improving cellular attachment via cell surface adhesion molecule receptors. This paper describes a new approach of using a polypeptide resurfacing method to enhance the attachment of cells to HyA strands. HyA strands were crosslinked by glutaraldehyde and then resurfaced with poly-D-lysine, poly-L-lysine, glycine, or glutamine. After inoculation with fibroblasts in vitro, modified HyA was evaluated with histological and immunohistochemical staining methods for cell adhesion and proliferation. Modified HyA with fibroblast cells also were implanted in vivo. The results show that (1) both polylysines enhanced fibroblast adhesion to crosslinked HyA strands; (2) HyA strands were able to be crosslinked well by 3 days of treatment in glutaraldehyde, and as a biomaterial they could resist biodegradation; (3) modified HyA has good biocompatibility, both in vitro and in vivo. The results demonstrate that HyA material resurfaced by polypeptides has positive advantages for cellular adhesion. Resurfaced HyA has much potential as an improved biomaterial for clinical usage.

Enhancement of axon growth by detergent-extracted nerve grafts.

BACKGROUND: The immunogenicity of nerve allografts is responsible for their rejection. We have developed a method for preparing cell-free nerve grafts using lysophosphatidylcholine to remove cells, axons, and myelin sheaths. METHODS: The remaining intact nerve extracellular matrix is the extracted nerve graft (eNG). Cultured neonatal Schwann cells were micro-injected into the eNG to form recellularized nerve grafts (rNG). eNG, rNG, and normal isografts (15 mm long) were implanted in the peroneal nerves of F-344 rats. Ten rats were given an eNG on the right, and an isograft on the left. Ten rats were given an rNG on the right, and a sham operation on the left. Sham operation was used as the control and the isograft was used as the benchmark procedure. Walking track analysis was performed every 15 days after surgery to determine the peroneal functional index. Morphometric analysis of the distal peroneal nerve and extensor digitorum muscle weight were analyzed 3 months after surgery. RESULTS: The three types of grafted legs had the classical effect observed after peripheral nerve repair, with decreased functional ability, decreased target muscle weight, fewer large nerve fibers, and more small nerve fibers. Isografts, eNG, and rNG all had similar patterns of peroneal functional index improvement after implantation. The extensor digitorum longus muscle weight and axon counts for the three types of graft were not statistically different. Hence, eNG and rNG can enhance nerve regeneration in the same way as isografts. The host Schwann cells that invaded the implanted eNG probably acted in the same fashion as the cultured Schwann cells injected into the rNG and the resident cells of isografts. CONCLUSIONS: The great permeability of the longitudinally oriented matrix of eNG to cells is, therefore, a major advantage over the reported poor permeability of freeze-thawed nerve grafts.