A regenerative peripheral nerve interface allows real-time control of an artificial hand in upper limb amputees.

Peripheral nerves provide a promising source of motor control signals for neuroprosthetic devices. Unfortunately, the clinical utility of current peripheral nerve interfaces is limited by signal amplitude and stability. Here, we showed that the regenerative peripheral nerve interface (RPNI) serves as a biologically stable bioamplifier of efferent motor action potentials with long-term stability in upper limb amputees. Ultrasound assessments of RPNIs revealed prominent contractions during phantom finger flexion, confirming functional reinnervation of the RPNIs in two patients. The RPNIs in two additional patients produced electromyography signals with large signal-to-noise ratios. Using these RPNI signals, subjects successfully controlled a hand prosthesis in real-time up to 300 days without control algorithm recalibration. RPNIs show potential in enhancing prosthesis control for people with upper limb loss.

Title: Quantifying the change of spasticity after intrathecal baclofen administration: A descriptive retrospective analysis.

OBJECTIVES: Exploratory research quantifying the change of spasticity among patients who underwent baclofen intrathecal drug delivery system (IDDS) implantation. PATIENTS AND METHODS: 88 patients with a baclofen IDDS were identified. Patient characteristics, spasticity scores pre/post intrathecal baclofen test dose, and IDDS perioperative implantation records were collected. The primary outcome was to quantify the extent to which there was a change in Modified Ashworth Scores (MAS) pre/post-intrathecal baclofen test dose administration. Secondary outcomes included the prevalence of perioperative IDDS implantation complications. RESULTS: The mean age at IDDS implant was 44.2 years (range, 19-71), and 62.5% were male. 45.5% had spasticity of spinal cord origin, 9% of cerebral origin, and 45.5% of other upper motor neuron dysfunction. Reduction of MAS in the spinal cord origin group was 2.6 (mean, 3.5 to 0.9), cerebral origin group was 2.9 (mean, 3.3 to 0.4), and other origin group was 2.5 (mean, 3.6 to 1.1). In all patients, post dural puncture headache was the most commonly reported complication at 22.7%. CONCLUSION: This report offers novel findings documenting a quantifiable change of at least two points on the MAS before and after intrathecal baclofen test dose as statistically significant and could prove to be useful information to enhance the decision making process to proceed with intrathecal baclofen beyond assessment of functional abilities.

Can Ultrasound Be Used to Improve the Palpation Skills of Physicians in Training? A Prospective Study.

BACKGROUND: Accurate diagnosis of musculoskeletal disorders relies heavily on the physical examination, including accurate palpation of musculoskeletal structures. The literature suggests that there has been a deterioration of physical examination skills among medical students and residents, in part due to increased reliance on advanced imaging. It has been shown that knowledge of musculoskeletal anatomy and physical examination skills improve with the use of ultrasound; however, the literature is limited. OBJECTIVE: To determine whether ultrasound can improve the ability of physicians in training (residents) to palpate the long head of the biceps tendon (LHBT) in the bicipital groove. DESIGN: Prospective study design. SETTING: Tertiary care center. PARTICIPANTS: Ten physical medicine and rehabilitation residents served as subjects. Exclusion criteria included the presence of any condition that precluded their ability to palpate. Three volunteers were used as models. Model exclusion criteria included anything that distorted normal shoulder anatomy or inhibited examiner palpation. Three investigators with experience performing diagnostic musculoskeletal ultrasound were used to confirm palpation attempts. METHODS: Subjects attempted to palpate the LHBT bilaterally in the bicipital groove of each model. Investigators assessed the accuracy of the palpation attempt using real-time ultrasonography. Subjects participated in a 30-minute ultrasound-assisted training session learning how to palpate the LHBT in the bicipital groove with ultrasound confirmation. After the ultrasound training session, subjects again attempted to palpate the LHBT in the bicipital groove of each model with investigator confirmation. MAIN OUTCOME MEASUREMENTS: LHBT palpation accuracy rates preintervention versus postintervention. RESULTS: Pretraining LHBT palpation accuracy was 20% (12/60 attempts). Post-ultrasound training session accuracy was 51.7% (31/60 attempts; P ≤ .001). CONCLUSIONS: Our findings demonstrate that palpation accuracy improves after ultrasound assisted LHBT palpation training. These data suggest that the use of ultrasound may be beneficial when teaching musculoskeletal palpation skills to health care professionals. LEVEL OF EVIDENCE: II.

Ultrasound-Guided Fasciotomy for Chronic Exertional Compartment Syndrome: A Cadaveric Investigation.

BACKGROUND: Chronic exertional compartment syndrome (CECS) is a common cause of exertional leg pain. It is commonly treated with a surgical fasciotomy, which has a surgical complication rate of up to 16% and takes approximately 6-12 weeks to return to preprocedure activity levels. Therefore, the development of a less invasive, effective outpatient intervention to treat CECS is desirable. OBJECTIVE: To describe and validate an ultrasound-guided (USG) fasciotomy technique for the anterior and lateral compartments of the lower limb in an unembalmed cadaveric model. DESIGN: Prospective, cadaveric laboratory investigation. SETTING: Academic institution procedural skills laboratory. SUBJECTS: Ten unembalmed cadaveric knee-ankle-foot specimens from 1 female (2 specimens) and 7 male donors aged 62-91 years (mean 78.6 years) with body mass indices of 18.9-35.3 kg/m2 (mean 27.1 kg/m2). METHODS: Two experienced operators each performed USG anterior and lateral compartment fasciotomies on 5 unembalmed cadaveric legs. A third physician subsequently dissected the legs to assess the continuity of the fasciotomies and to identify any neurovascular damage related to the procedures. MAIN OUTCOME MEASURES: Fasciotomy length (in centimeters) and classification by completeness (achieved target length or did not achieve target length) and continuity (continuous or discontinuous) based on predetermined criteria. Muscles, retinaculae, and neurovascular structures were assessed for damage. RESULTS: No neurovascular injuries occurred in any of the 20 USG fasciotomies. The average fasciotomy length was 22.5 cm. All 20 of the fasciotomies achieved the target length. A continuous cephalocaudal fasciotomy was accomplished in 13 of 20 fasciotomies. When a fasciotomy was not continuous, the average length and number of intact fascial bands was 1.52 cm and 2.3, respectively. CONCLUSIONS: USG fasciotomy of the anterior and lateral leg compartments can be safely performed in a cadaveric model and can achieve a fasciotomy length comparable to surgical fasciotomy. Most procedures successfully achieved a continuous cephalocaudal fasciotomy, although small areas of intact fascial bands were identified in approximately one-third of procedures. The clinical significance of this finding is indeterminate. Given the safety demonstrated with this minimally invasive USG fasciotomy in a cadaveric model, further research is warranted to develop and refine the technique for clinical application. LEVEL OF EVIDENCE: Not applicable.

Ultrasound-Guided Knee Procedures.

Most knee structures can be accurately targeted using ultrasound guidance. These structures are usually superficial, and the overlying soft tissues are mobile and compressible, facilitating excellent visualization with a high-frequency linear array transducer. The circumferential accessibility to the knee affords flexibility and often multiple procedural approach options. In most cases, an in-plane approach is easily achieved. Studies of ultrasonography-guided knee procedures have consistently shown high accuracy, and its use is particularly beneficial for obese patients, diagnostic injection specificity, safety, and precise targeting of pathology. More studies are needed to assess the clinical efficacy and cost-effectiveness of ultrasonography-guided knee procedures.

Inflammatory Myopathy Causing Leg Pain in a Soccer Player: Case Report and Return-to-Play Considerations.

Leg pain is a common condition in athletes as well as in the general population, and has a broad differential diagnosis that includes musculoskeletal, vascular, rheumatologic, and neurologic etiologies. Idiopathic inflammatory myopathy (IM) is a relatively uncommon but recognized etiology of leg pain. In this case, we describe an acute presentation of IM in an athlete resulting in leg pain and activity limitation. The available literature suggests that moderate-intensity exercise is safe and beneficial in idiopathic IM, but studies to date have not assessed the effects of high-intensity exercise in IM or provided recommendations for return to competitive contact sport in this population.

Optimal Elbow Angle for Sonographic Visualization of the Ulnar Collateral Ligament.

OBJECTIVE: To formally examine the sonographic appearance of the elbow ulnar collateral ligament (UCL) at 30° versus 70° of elbow flexion in asymptomatic baseball pitchers. DESIGN: A prospective, cross-sectional design. SETTING: Sports medicine clinic in a tertiary academic medical center. PARTICIPANTS: Thirty asymptomatic adolescent baseball pitchers 13-18 years of age (mean 15.8 years), with at least 3 years of continuous pitching experience and no significant history of elbow pain or injury. METHODS: Static sonographic images of the bilateral UCLs were obtained at 30° and 70° of elbow flexion by a single experienced examiner. Images were anonymized and randomized into a slide set. Three clinicians with different levels of ultrasound experience reviewed the static 30° and 70° images for each elbow and chose their preferred image based on UCL conspicuity. The clinicians reviewed a re-randomized slide set 1 week later. A different study co-investigator measured UCL cross-sectional area (CSA) on all images using ultrasound machine electronic calipers. MAIN OUTCOME MEASURES: Preference for the sonographic conspicuity of the UCL at 30° versus 70° of elbow flexion, and UCL CSA at 30° versus 70° of flexion. RESULTS: Each clinician demonstrated a significant preference for UCL images obtained at 70° of flexion when compared to those obtained at 30° (80.3% overall preference for 70°, P < .001). There was no statistically significant effect of clinician experience or arm dominance on image preference. The sonographically determined CSA of the UCLs were on average 1.4 mm(2) greater at 70° than at 30° of flexion (P < .001) when combining dominant and nondominant arms. CONCLUSIONS: Static sonographic evaluation of the UCL at 70° of elbow flexion should be integrated into UCL imaging protocols. Furthermore, when performing sonographically guided procedures targeting the UCL, clinicians should consider positioning the elbow at >30° of flexion to optimize UCL conspicuity and CSA.