Michael Morhart

Novel targeted sensory reinnervation technique to restore functional hand sensation after transhumeral amputation.

We present a case study of a novel variation of the targeted sensory reinnervation technique that provides additional control over sensory restoration after transhumeral amputation. The use of intraoperative somatosensory evoked potentials on individual fascicles of the median and ulnar nerves allowed us to specifically target sensory fascicles to reroute to target cutaneous nerves at a distance away from anticipated motor sites in a transhumeral amputee. This resulted in restored hand maps of the median and ulnar nerve in discrete spatially separated areas. In addition, the subject was able to use native and reinnervated muscle sites to control a robotic arm while simultaneously sensing touch and force feedback from the robotic gripper in a physiologically correct manner. This proof of principle study is the first to demonstrate the ability to have simultaneous dual flow of information (motor and sensory) within the residual limb. In working towards clinical deployment of a sensory integrated prosthetic device, this surgical method addresses the important issue of restoring a usable access point to provide natural hand sensation after upper limb amputation.

Validity and reliability of the Purdue Pegboard Test in carpal tunnel syndrome.

There is a paucity of validated tests to quantify hand function impairment due to carpal tunnel syndrome (CTS). The aim of this study was to test the validity and reliability of the Purdue Pegboard Test (PPT) in CTS patients. We compared 190 CTS patients with 122 healthy, age‐matched controls. CTS severity was determined based on electrophysiologic parameters and the Levine Self‐Assessment Questionnaire. The time to complete the PPT and the test–retest reliability were tested. The test–retest reliability was high with an intraclass correlation coefficient of 0.91. Compared to healthy controls, the CTS patients were significantly slower. Although the functional performance generally declined with increasing severity of electrophysiologic abnormalities, the correlation between hand function decline and symptom severity in the young and middle‐aged groups was low. We conclude that the PPT is a valid and reliable tool to quantify functional impairment caused by CTS. It can be a useful outcome measure in young and middle‐aged patients. Muscle Nerve , 2011

Electrical stimulation enhances sensory recovery: A randomized controlled trial

Brief postsurgical electrical stimulation (ES) has been shown to enhance peripheral nerve regeneration in animal models following axotomy and crush injury. However, whether this treatment is beneficial in humans with sensory nerve injury has not been tested. The goal of this study was to test the hypothesis that ES would enhance sensory nerve regeneration following digital nerve transection compared to surgery alone.

First Permanent Implant of Nerve Stimulation Leads Activated by Surface Electrodes, Enabling Hand Grasp and Release The Stimulus Router Neuroprosthesis

Background. More than 150 000 neuroprostheses (NPs) have been implanted in people to restore bodily function in a variety of neural disorders. The authors developed a novel NP, the Stimulus Router System (SRS), in which only passive leads are implanted. Each lead picks up a portion of the current delivered through the skin by an external stimulator. Objective. The authors report on the first human implant of an SRS. Methods. The recipient was a tetraplegic man with bilateral hand paralysis. Three SRS leads were implanted in his right forearm to activate the finger extensors, finger flexors, and thumb flexor. A wristlet containing a surface stimulator and electrodes was used to pass trains of electrical pulses through the skin to each lead. Hand opening and grasp were controlled via a wireless earpiece that sensed small tooth-clicks and transmitted signals to the wristlet. Results. The current required to activate the muscles was less than half that required prior to implantation and below perceptual threshold. Maximal grip force and hand opening aperture were both larger using the SRS. The implanted leads have remained functional for 3 years. The recipient reported various tasks of daily life that improved during SRS usage. An electronic counter revealed mean monthly usage of 18.5 hours, equivalent to 55 hours of continuous manual activity. Conclusions. This first implant of the SRS indicates that it can be effective and reliable and has potential to provide an alternative to existing NPs.

Pearls and pitfalls of needle aponeurotomy in Dupuytren's disease.

Background: Dupuytren’s disease is a benign, progressive, fibroproliferative disease, and despite advances in basic science and technology, there remains no cure. To date, open fasciectomy procedures remain the criterion standard for the treatment of Dupuytren’s disease despite a significant complication rate and recovery time. Needle aponeurotomy, a less invasive treatment, is associated with reduced complications and quicker recovery. Methods: A literature review and a compilation of over 700 procedures was performed to highlight the clinical relevance of needle aponeurotomy. A step-by-step description of the author’s technique for needle aponeurotomy is presented, emphasizing the pearls and pitfalls of the procedure. Results: Recurrence rates for open fasciectomy are 5 to 10 percent per year compared with rates for needle aponeurotomy, which are 10 to 20 percent per year. Overall complication rates are much less frequent with needle aponeurotomy, with skin tears being the most common (3 percent). Needle aponeurotomy is cost effective compared with open fasciectomy. Recurrent proximal interphalangeal joint flexion contractures remain the most problematic in terms of correction. Conclusions: Needle aponeurotomy has been shown to be an extremely useful adjunct available to the surgeon in the treatment of Dupuytren’s disease. This procedure can be performed easily in an outpatient setting or office and carries with it dramatic results. Needle aponeurotomy has a lower complication rate and quicker recovery when compared with open fasciectomy and is therefore offered to patients as a first-line treatment.

Updates in Targeted Sensory Reinnervation for Upper Limb Amputation

Advanced robotic devices capable of simulating the dexterous ability of the upper limb with an array of internal sensors have raised the enticing prospect of replacing the lost intricate functions of the arm following upper limb amputation. However, a large gap still exists in the application of this technology to the human user. In particular, the ability to provide physiologically relevant sensory feedback—to have the amputee feel the prosthetic hand as their own—has not yet been achieved. Although a number of different approaches are being investigated, targeted sensory reinnervation, a refinement of the original targeted muscle reinnervation procedure, is the most recent and promising development in the effort to create a functional human–machine interface with a closed loop sensory feedback system. This technique aims to re-establish hand sensation on the skin so that it can be readily accessed non-invasively during functional tasks. Recent efforts are being directed towards distributing hand maps widely on the stump without interference of sensations from the native area. In this article, we will review the surgical approaches that have been used for sensory reinnervation in upper arm amputation and compare the resultant outcomes and potential functional utility of the techniques.

Traumatic dislocation of the globe into the maxillary sinus

CASE REPORT We report a case of traumatic dislocation of the globe into the maxillary sinus following a bull-riding incident. COMMENTS Traumatic dislocations of the eye into the sinuses are rare, and urgent management and surgical repair are indicated.

Discriminative validity and test-retest reliability of the Dellon-modified Moberg pick-up test in carpal tunnel syndrome patients.

There is a scarcity of validated hand performance tests with proven reliability for quantifying functional deficits in patients with carpal tunnel syndrome (CTS). The Dellon‐modified Moberg pick‐up test (DMMPUT), composed of commonly used daily objects, is potentially well suited for that purpose. This study was designed to evaluate the test–retest reliability and discriminative validity of the DMMPUT in CTS patients. We compared 162 CTS patients with 116 age‐matched controls. CTS severity was determined based on electrophysiological parameters and Levines Self‐Assessment Questionnaire. The mean time to complete each subset of the DMMPUT by the CTS patients was compared with that by the healthy subjects. Test–retest reliability was examined in 46 CTS patients. Discriminative validity was demonstrated through a significant difference in test completion time between the CTS subjects and their age‐matched controls. With few exceptions, the test scores declined with increasing severity of electrophysiological abnormalities and subjective symptom severity. Test–retest reliability of the DMMPUT was high with an intra‐class correlation coefficient of 0.91. The DMMPUT has discriminative validity and high test–retest reliability in patients with CTS. It can be a useful standardized outcome measure to gauge disease severity.

Functional outcome after the Hoffer procedure.

Background: Children with obstetrical brachial plexus injury often develop an internal rotation and adduction contracture about the shoulder as a secondary deformity, resulting in an inability to externally rotate and abduct the shoulder. The Hoffer procedure is evaluated for its potential benefit in improving shoulder abduction and external rotation and its impact on activities of daily living. Methods: This is a retrospective review of patients treated in brachial plexus injury clinic who underwent tendon transfer procedures about the shoulder. Preoperative and postoperative active movement and active range of motion were measured and recorded using the Mallet scale and the Active Movement Scale. Results: Twenty patients were included in the study. Average age at time of surgery was 6.35 years. Thirteen patients had primary brachial plexus reconstructive surgery and four patients had concomitant wrist extension tendon transfer procedures. All patients had full passive range of motion preoperatively. The average follow-up period was 25.45 months. Average differences in pre-Hoffer and post-Hoffer Mallet scale scores are as follows: active abduction, 1.20; external rotation, 1.35; hand-to-neck, 1.25; hand-to-back, 0.75; hand-to-mouth, 0.65; and aggregate score, 5.20 (p < 0.001 for all). Average differences in relevant pre-Hoffer and post-Hoffer Active Movement Scale scores are as follows: shoulder abduction, 2.10; shoulder external rotation, 4.25; and shoulder internal rotation, −0.80. All patients maintained full range of motion passively; thus, no functional loss was experienced. These results showed very high statistical significance (p < 0.001 for all) and clinical significance. Younger patients (⩽6 years) and those with better preoperative shoulder flexion and shoulder internal rotation yielded better postoperative results. Conclusions: The Hoffer procedure provides clinically and statistically significant improvement in external rotation and abduction while preserving functional internal rotation range in the child with obstetrical brachial plexus palsy and secondary shoulder deformity. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

First permanent human implant of the Stimulus Router System, a novel neuroprosthesis: Preliminary testing of a polarity reversing stimulation technique

Neuroprostheses (NPs) are electrical stimulators that help to restore sensory or motor functions lost as a result of neural damage. The Stimulus Router System (SRS) is a new type of NP developed in our laboratory. The system uses fully implanted, passive leads to “capture” and “route” some of the current flowing between pairs of surface electrodes to the vicinity of the target nerves, hence eliminating the need for an implanted stimulator. In June 2008, 3 SRS leads were implanted in a tetraplegic man for restoration of grasp and release. To reduce the size of the external wristlet and thereby optimize usability, we recently implemented a polarity reversing stimulation technique that allowed us to eliminate a reference electrode. Selective activation of three target muscles was achieved by switching the polarities of the stimulus current delivered between pairs of surface electrodes located over the pick-up terminals of the implanted leads and reducing the amplitude of the secondary phases of the stimulus pulses.