Ethan R. Wiesler

Ultrasound of nerve and muscle

Over the last two decades, ultrasound has developed into a useful technology for the evaluation of diseases of nerve and muscle. Since it is currently not used at by the majority of clinicians involved in diagnosis or care of patients with neuromuscular disorders, this review briefly describes the technical aspects of ultrasound and its physical principles. It relates normal muscle anatomy and movement to ultrasound images in the axial and sagittal planes and follows with a discussion of ultrasound findings in chronic muscle disease. These include evident atrophy and the loss of the hypoechoic architecture of normal muscle tissue. It highlights evolving uses of the technique to measure other pathologic changes in disease including altered muscle dynamics. With high-resolution instruments nerve imaging has now become standard, and the relationships of median nerve anatomy and observations of static and dynamic images from ultrasound are reviewed. Changes seen in carpal tunnel syndrome include significant increases in the cross-sectional area of the nerve just proximal to the site of compression, loss of hyperechoic intensities within nerve, and reduced mobility. Preliminary use of the technique for the study of other nerves is reviewed as well. Ultrasound is an ideal tool for the clinical and research investigation of normal and diseased nerve and muscle complementary to existing diagnostic techniques. As the technology continues to evolve, it will likely assume a more significant role in these areas as those most able to exploit its potential, clinical neurophysiologists and neuromuscular clinicians, incorporate its use at the bedside.

Ankle Flexibility and Injury Patterns in Dancers

Lower-extremity injuries are common among dancers and cause significant absences from rehearsals and performances. For this study of lower-extremity injuries in 101 ballet and 47 modern dance students, injuries requiring medical attention sustained over 1 academic year were associated with the following data obtained at the beginning of the school year: ankle flexibility, sex, dance discipline, previous injury, body mass in dex, and years of training. Eighty-three of the 148 students (age range, 12 to 28 years) reported prior lower-limb injuries, the most common being ankle sprains (28% of all dancers). Previous leg injuries cor related significantly with lower dorsiflexion meas urements and with more new injuries. Female students had greater ankle and first metatarsophalangeal flexi bility. Modern dancers had greater ankle inversion. Ninety-four students sustained 177 injuries during the study, including 75 sprains or strains and 71 cases of tendinitis. Thirty-nine percent (N = 69) were ankle injuries; 18% (N = 33) were knee injuries; 23% (N = 40) were foot injuries; and 20% (N = 35) were either hip or thigh injuries. Sixty-seven percent (N = 78) of the injured students were ballet dancers. Age, years of training, body mass index, sex, and ankle range of motion measurement had no predictive value for injury; previous injury and dance discipline both correlated with increased risk of injury.

Avoiding Catastrophic Complications of Stroke and Death Related to Shoulder Surgery in the Sitting Position

The beach-chair position in shoulder surgery provides advantages to the surgeon and anesthesiologist. However, cautious interpretation of the patients blood pressure is essential, especially when the blood pressure cuff is placed at the calf. The calf pressure should be interpreted relative to the heart-level pressure to avoid iatrogenic cerebral hypoperfusion related to hypotensive anesthesia. Possible complications of cerebral hypoperfusion are permanent neurologic impairment, stroke, and death.

Current Concepts in Wrist Arthroscopy

The purpose of this article is to review the recent literature on arthroscopic treatment of distal radius fractures (DRFs), triangular fibrocartilage complex injuries, intercarpal ligament injuries, and ganglion cysts, including the use of electrothermal devices. A major advantage of arthroscopy in the treatment of DRFs is the accurate assessment of the status of the articular surfaces and the detection of concomitant injuries. Nonrandomized studies of arthroscopically assisted reduction of DRFs show satisfactory results, but there is only 1 prospective randomized study showing the benefits of arthroscopy compared with open reduction-internal fixation. Wrist arthroscopy plays an important role as part of the treatment for DRFs; however, the treatment for each practitioner and each patient needs to be individualized. Wrist arthroscopy is the gold standard in the diagnosis and treatment of triangular fibrocartilage complex injuries. Type 1A injuries may be successfully treated with debridement, whereas the repair of type 1B, 1C, and 1D injuries gives satisfactory results. For type 2 injuries, the arthroscopic wafer procedure is equally effective as ulnar shortening osteotomy but is associated with fewer complications in the ulnar positive wrist. With interosseous ligament injuries, arthroscopic visualization provides critical diagnostic value. Debridement and pinning in the acute setting of complete ligament tears are promising and proven. In the chronic patient, arthroscopy can guide reconstructive options based on cartilage integrity. The preliminary results of wrist arthroscopy using electrothermal devices are encouraging; however, complications have been reported, and therefore, their use is controversial. In dorsal wrist ganglia, arthroscopy has shown excellent results, a lower rate of recurrence, and no incidence of scapholunate interosseous ligament instability compared with open ganglionectomy. Arthroscopy in the treatment of volar wrist ganglia has yielded encouraging preliminary results; however, further studies are warranted to evaluate the safety and efficacy of arthroscopy.

Median nerve changes following steroid injection for carpal tunnel syndrome.

Introduction: Neuromuscular ultrasound is a painless, radiation‐free, high‐resolution imaging modality for assessment of the peripheral nervous system. The purpose of this study was to use neuromuscular ultrasound to assess the changes that occur in the median nerve after steroid injection for carpal tunnel syndrome (CTS). Methods: Ultrasound and nerve conduction studies were performed at baseline and 1 week, 1 month, and 6 months after steroid injection in 19 individuals (29 wrists) with CTS. Results: Significant changes were noted in median nerve cross‐sectional area (P < 0.001), mobility (P = 0.001), and vascularity (P = 0.042) at the distal wrist crease after steroid injection, and the nerve cross‐sectional area correlated with symptom score and electrodiagnostic parameters. Changes in the ultrasonographic parameters were seen within 1 week of injection. Conclusions: These findings suggest neuromuscular ultrasound is potentially helpful for the assessment of individuals undergoing treatment for CTS, as typical changes can be expected after successful treatment injection. Muscle Nerve 44: 25–29, 2011

Diagnostic ultrasound for nerve transection

The current approach for localizing and assessing the severity of traumatic peripheral nerve injuries involves clinical evaluation and electrodiagnostic studies. However, the ability of this approach to determine the extent of nerve damage within the first 6 weeks after trauma is limited. This is problematic because outcome is improved with early surgical intervention after complete nerve transection. This led us to explore alternative techniques, such as imaging, for assessing peripheral nerve injuries. Twelve fresh cadavers were obtained and after inspection 20 arms were deemed suitable for inclusion in the study. Random sites were transected in median, ulnar, and radial nerves, and sham skin incisions were performed throughout the arm. These nerves were then systematically scanned by an ultrasonographer blinded to the nerve transection sites, who made a final decision as to whether the nerve was transected. High‐resolution ultrasound was able to identify transected nerves in the upper extremity with 89% sensitivity and 95% specificity in fresh cadavers. This proof‐of‐concept study shows that ultrasound can accurately identify nerve transection, which should lead to further ultrasound studies in patients with traumatic peripheral nerve injuries. Muscle Nerve, 2007

Reconstruction of Essex-Lopresti Injury of the Forearm: Technical Note

Longitudinal instability of the forearm resulting from an Essex-Lopresti injury is a surgical challenge, and no technique has yet met universal success. A new technique is presented here consisting of reconstruction of the radial head, leveling of the distal radioulnar joint, reconstruction of the central band of the interosseous membrane by using a pronator teres rerouting technique, and finally repair of the triangular fibrocartilage complex. It is hoped that by addressing all of the contributing longitudinal stabilizing structures, the longitudinal instability of the forearm will be controlled. The technique is challenging and requires much surgical experience.

Traumatic valgus instability of the elbow: pathoanatomy and results of direct repair.

BACKGROUND The medial collateral ligament provides valgus stability to the elbow. The purpose of the present study was to describe the pathoanatomy of acute traumatic medial collateral ligament ruptures and to report the rationale and results of direct repair. METHODS Between 1996 and 2006, eleven athletes presented with acute rupture of the medial collateral ligament of the elbow and no history of dislocation. Three patients had received steroid injections for the treatment of medial epicondylitis, but none had a history of medial elbow insufficiency. All patients demonstrated gross valgus instability on clinical examination and medial joint space widening on valgus stress radiographs. Complete avulsion of the medial collateral ligament from its humeral origin was documented with magnetic resonance imaging in all patients. Operative findings uniformly demonstrated avulsion of the flexor-pronator muscles with distal retraction. The underlying medial collateral ligament was avulsed in a sleeve-like fashion from the denuded medial epicondyle. The ligament was directly reattached to its footprint. The avulsed flexor-pronator tendon was repaired to the residual tendon with use of interrupted figure-of-eight nonabsorbable sutures. All patients were followed for a minimum of sixteen months with serial clinical examinations, radiographs, and the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. RESULTS Full active range of motion was achieved in ten patients; the remaining patient had a 20 degrees flexion contracture. Three patients had acute ulnar nerve palsies at the time of the injury, and all three recovered complete motor and sensory function by six months after the injury. Nine of the eleven patients returned to competitive college athletics between four and six months. The mean DASH score at the time of the most recent follow-up was 6. CONCLUSIONS Direct repair of an acute traumatic medial collateral ligament avulsion of the elbow reliably restores valgus stability, even in throwing athletes.

Consensus Statement on Shoulder Instability

The understanding and treatment of shoulder instability comprise a rapidly evolving area of interest in orthopaedics. Evaluation methods are becoming more specific in showing the exact pathologies causing the symptoms. Magnetic resonance arthrography and arthroscopy have contributed to this development. The patient with an unstable shoulder should be thoroughly evaluated through their history and specific clinical tests of the shoulder as well as the scapulothoracic joint. Often, shoulder instability can be classified after this primary evaluation. Magnetic resonance arthrography and arthroscopy are the gold standards in soft-tissue evaluation, whereas specialized radiographic examinations and computed tomography scans are used to assess bony defects. Patients are treated according to the pathology found on preoperative or pretreatment evaluation. Multiple factors need to be considered before the treatment program is instituted, including the patients age, activity demands, associated pathology and dysfunction, soft-tissue pathology, degree of instability, direction, frequency, and etiology. Treatment can be nonoperative or arthroscopic or open repair. Soft-tissue pathology and bony defects should be addressed, and the surgeons preferred method and skills are important in choosing the right treatment for the patient. The patient should be informed about possible complications, restrictions during the treatment period, and the prognosis for the particular type of instability. To improve progress in shoulder orthopaedics, one of the most important factors can be a universal agreement on an outcome measurement tool that is well designed and validated.

Arthroscopic Management of Volar Lunate Facet Fractures of the Distal Radius

The clinical outcome of an intraarticular distal radius fracture is generally thought to be associated with the following factors: amount of radial deformity, joint congruity, and associated soft-tissue injuries. The proposed technique to manage this fracture pattern that involves a displaced volar lunate facet fragment uses wrist arthroscopy and pinning. Distraction of the fracture before arthroscopy is accomplished either by external fixation or by the arthroscopy tower. A freer elevator is introduced dorsally to disimpact the fragments, and next, a nerve hook is used to reduce the volar lunate facet, which is subsequently pinned to the radial styloid. The remaining fragments are reduced with interfragmentary pin fixation, and this anatomical articular construct is fixed to the radial metaphysis. The advantages of this technique are: (a) accurate assessment of articular congruency by direct visualization, (b) identification and repair of associated lesions, and (c) minimal soft tissue disruption. Potential disadvantages of external fixation supplemented by interfragmentary pins may be that it does not provide for rigid stable fixation, and therefore, does not allow for early motion compared to open reduction and internal fixation. Furthermore, it is technically challenging, and is therefore suggested as an alternative for the aforementioned fracture pattern.