High-resolution median nerve sonographic measurements: correlations with median nerve conduction studies in healthy adults.

OBJECTIVES: To study relationships between median wrist and forearm sonographic measurements and median nerve conduction studies. METHODS: The study population consisted of a prospective convenience sample of healthy adults. Interventions included high-resolution median nerve sonography and median motor and sensory nerve conduction studies. Main outcome measures included median motor nerve compound muscle action potential amplitude, distal latency, and conduction velocity; sensory nerve action potential amplitude and distal latency; and sonographic median nerve cross-sectional area. Median motor nerve and sensory nerve conduction studies of the index finger were performed using standard published techniques. A second examiner blinded to nerve conduction study results used a high-frequency linear array transducer to measure the cross-sectional area of the median nerve at the distal volar wrist crease (carpal tunnel inlet) and forearm (4 cm proximally), measured in the transverse plane on static sonograms. The outer margin of the median nerve was traced at the junction of the hypoechoic fascicles and adjacent outer connective tissue layer. RESULTS: Fifty median nerves were evaluated in 25 participants. The compound muscle action potential amplitude with wrist stimulation was positively related to the cross-sectional area, with the area increasing by 0.195 mm(2) for every millivolt increase in amplitude in the dominant hand (95% confidence interval, 0.020, 0.370 mm(2); P < .05) and 0.247 mm(2) in the nondominant hand (95% confidence interval, 0.035, 0.459 mm(2); P < .05). There was no significant linear association between the wrist median cross-sectional area and median motor and sensory distal latencies. Conduction velocity through the forearm was not significantly linearly associated with the forearm area or forearm-to-wrist area ratio (tapering ratio). The wrist area was inversely related to the sensory nerve action potential amplitude. CONCLUSIONS: Although associations were found between median nerve conduction study amplitudes and sonographic nerve measurements, they were not found for other parameters. Studying these relationships may increase our understanding of when to best use these procedures.

The downed runner.

Race coverage can be a rewarding experience for the sports medicine clinician. Several conditions are likely to present to the medical tent, and accurate diagnosis is critical to proper treatment. An algorithm approach as outlined in this article can provide a starting point for the assessment of the downed runner. Recognition of the primary causes for collapse can help to instigate the correct treatment approach. A proper history and physical examination often can help to differentiate significant cardiac events from the more innocuous EAC. Furthermore, avoiding immediate i.v. fluids in the downed runner is prudent, at least until an appropriate diagnosis is made. This will help to prevent iatrogenic hyponatremia. In sum, proper preparation and knowledge of the ailments that affect long distance runners will help to maintain an effective medical tent on race day.

Pathogenesis of lumbar spinal stenosis pain: why does an asymptomatic stenotic patient flare?

This article discusses the pathogenesis of lumbar spinal stenosis pain and presents a theory on why asymptomatic stenotic patients flare.

Posterior Knee Pain and Its Causes: A Clinician's Guide to Expediting Diagnosis.

Because posterior knee pain is a relatively uncommon patient complaint, its etiology is challenging and often elusive. The differential diagnosis for posterior knee pain can be vast, so clues for distinguishing causes are important. Many clinicians are unfamiliar with this complicated anatomic area and may not have a standard clinical evaluation to establish a cause of the patient's pain. Review of several known causes of knee pain can provide the examiner with a more comprehensive list of potential disorders to consider as differential diagnoses when patients present with posterior knee pain.

Programmatic design for teaching the introductory skills and concepts of lumbar spine procedures to physiatry residents: a prospective multiyear study.

OBJECTIVE: The objective of this study was to determine the effectiveness of a 2-day course teaching the introductory skills and concepts of lumbar spine procedures to physiatry residents. DESIGN: This is a 3-yr prospective study of a 2-day musculoskeletal course teaching the introductory skills and concepts of lumbar spinal procedures to the residents at a large academic physical medicine and rehabilitation program. The residents attending the course took multiple-choice pretests and posttests as well as participated in a procedural skills competency demonstration. RESULTS: Forty-two residents participated. The results were stratified according to the level of training and repetition of the material and revealed gains of medical knowledge at each level of residency training (P < 0.001). The postgraduate year 2 residents seemed to have the greatest overall improvement (P = 0.04). Half of the residents scored lower than 65% on the pretest, and these residents ultimately had the largest posttest gains. Forty (95.2%) residents achieved a grade of pass in the skills-based test. The residents felt that the course was valuable or extremely valuable. CONCLUSIONS: The comprehensive 2-day course teaching the skills and concepts of spinal interventions for physiatry residents enhances medical knowledge as an introduction to interventional spine care. Those who benefited the most were the residents who had the greatest deficit of medical knowledge on this topic before the course. This course curriculum does not replace fellowship training or closely monitored mentorship in the performance of spinal procedures.

Adverse events associated with fluoroscopically guided sacroiliac joint injections.

OBJECTIVE: To describe the type, incidence, and factors that contribute to adverse events associated with fluoroscopically guided intra-articular sacroiliac joint injections (IASIJ). DESIGN: A retrospective cohort study. SETTING: Tertiary, academic, outpatient physical medicine and rehabilitation interventional spine clinic. PARTICIPANTS: English-speaking adults aged 18-90 years who underwent fluoroscopically guided IASIJ injections between March 8, 2004, and April 19, 2007. INTERVENTIONS: After IASIJ injections, 3 senior researchers recorded the presence and types of adverse events. The relationship of adverse events with age, gender, fluoroscopy time, vital signs, and trainee presence was analyzed with the Fisher exact or the Wilcoxon rank sum 2-sided tests. MAIN OUTCOME MEASURES: The frequency of immediate (during or immediately after the procedure) or delayed (within 24-72 hours after the procedure) adverse events. RESULTS: A total of 162 patients (133 women) underwent 191 procedures. The range of subject age was from 20 to 90 years (15.8 years, standard deviation [SD]). The range (SD) of the preprocedure 11-point Likert Pain Scale was from 1.0 to 10.0 (2.0) and for the postprocedure 11-point Likert Pain Scale was from 0.0 to 9.0 (2.5). Trainees were involved in 57% of the procedures. Reported immediate adverse events were vasovagal reaction (2.1% [n = 4]) and steroid-clogged needle (0.5% [n = 1]). Follow-up data were available for 132 of 191 procedures (69%). There were 32 adverse events reported at a mean follow-up interval of 2 days, of which, the most frequent adverse events were injection-site soreness (12.9% [n = 17]), pain exacerbation (5.3% [n = 7]), and facial flushing and/or sweating (2.3% [n = 3]). Delayed adverse events decreased with older age (P = .0029). The patients who underwent bilateral procedures experienced more delayed adverse events than the patients who underwent unilateral procedures (P = .024). CONCLUSIONS: Fluoroscopically guided IASIJ injection is associated with minimal adverse effects. The most common immediate adverse event was vasovagal reaction, and the most common delayed adverse event was injection-site soreness. Younger age is significantly related to reported delayed adverse events.

The use of ultrasound in guiding musculoskeletal interventional procedures.

There has been an increase in the use of ultrasound (US) to help guide interventional procedures involving the musculoskeletal system. To perform these procedures safely and accurately, two steps must occur. First, the appropriate structure must be localized using diagnostic US imaging. Second, a needle must be guided under constant visualization toward the targeted tissue. Although US imaging can help place the needle and, hence, therapeutic medication more accurately, there is still debate about whether or not image-guided procedures result in improved outcomes. This article discusses the advantages and disadvantages of performing US-guided injections and describes injection principles and techniques. Studies examining the efficacy of US-guided procedures are reviewed.

Advances and utility of diagnostic ultrasound in musculoskeletal medicine.

Musculoskeletal ultrasound (US) can serve as an excellent imaging modality for the musculoskeletal clinician. Although MRI is more commonly ordered in the United States for musculoskeletal problems, both of these imaging modalities have advantages and disadvantages and can be viewed as complementary rather than adversarial. For diagnostic US, relative recent advances in technology have improved ultrasound's ability to diagnose a myriad of musculoskeletal problems with enhanced resolution. The structures most commonly imaged with diagnostic musculoskeletal US, include tendon, muscle, nerve, joint, and some osseous pathology. This brief review article will discuss the role of US in imaging various common musculoskeletal disorders and will highlight, where appropriate, how recent technological advances have improved this imaging modality in musculoskeletal medicine. Additionally, clinicians practicing musculoskeletal medicine should be aware of the ability as well as limitations of this unique imaging modality and become familiar with conditions where US may be more advantageous than MRI.