Electromyography-related pain: Muscle selection is the key modifiable study characteristic

Future Considerations in the Diagnosis and Treatment of Compressive Neuropathies of the Upper Extremity

Compressive neuropathies of the upper extremity are among the most common conditions seen by hand surgeons. The diagnoses of carpal tunnel syndrome and cubital tunnel syndrome have traditionally been made by a combination of history, physical examination, and electrodiagnostic testing. However, findings can be nonspecific and electrodiagnostic testing is invasive for the patient. The diagnosis of compressive neuropathies continues to evolve as technology advances, and newer diagnostic modalities predominantly focus on preoperative diagnostic imaging with ultrasound and magnetic resonance imaging/neurography. With the advent of cheaper, faster, and less invasive imaging, the future may bring a paradigm shift away from electrophysiology as the gold standard for the preoperative diagnosis of compressive neuropathies. Intraoperative imaging of nerve health is an emerging concept that warrants further investigation, whereas postoperative imaging of nerve recovery with ultrasound and magnetic resonance imaging currently has a limited role because of nonspecific findings and potential for misinterpretation. Advances in surgical treatment of compressive neuropathies appear to center around the use of imaging for less invasive neurolysis techniques and other adjunctive treatments with nerve decompression. The management of failed peripheral nerve decompressions and recurrent compressive neuropathies remains challenging.

Pain perception during electrodiagnostic studies and the impact of learners

INTRODUCTION/AIMS

Electrodiagnostic testing (EDX) may be perceived as painful, which may influence patient expectations and test completion. Our aim was to characterize which component of the EDX was more painful, and to determine if any factors, particularly performance by a learner, influenced this perception.

METHODS

Participants were prospectively recruited and completed a brief questionnaire to rate their perception of pain before and after each component of the EDX. Demographic information and information about the test itself was collected.

RESULTS

A total of 251 participants were recruited, 55.3% female, with a mean age of 52.9 years. Most participants rated pain after nerve conduction studies (NCS) and needle electromyography (EMG) as mild to moderate with a similar number rating each component as more painful than the other. There was no effect of sex on overall ratings, although females felt that the test was more painful than anticipated more often than males. If a learner performed the EMG, it was more likely that the test would be rated as moderately to severely painful, and more likely for the EMG to be rated as more painful than the NCS (p<0.05).

DISCUSSION

The finding that NCS and EMG perceived pain were similar may help accurately inform patients of test expectations, guide test planning and help reduce the likelihood of incomplete or canceled testing. More effort might be required to help mitigate EMG pain when learners are involved.

Sonographic normal values for the cross-sectional area of the ulnar nerve: a systematic review and meta-analysis

PURPOSE

Nerve size is a commonly used sonographic parameter when assessing suspected entrapment of the ulnar nerve. We aimed to create a robust set of normal values, based on a critical review of published normal values.

METHODS

We performed a systematic evaluation of studies on normal ulnar nerve sizes, identified in PubMed, Embase, and Cochrane databases. Using meta-analyses, we determined pooled mean cross-sectional area (CSA) values for different anatomical locations of the ulnar nerve throughout the arm. Subgroup analyses were performed for gender, probe frequency, in- or exclusion of diabetic patients, position of the elbow and Asian versus other populations.

RESULTS

We identified 90 studies of which 77 studies were included for further analyses after quality review, resulting in data from 5772 arms of 3472 participants. Subgroup analyses show lower CSA values at at the wrist crease and proximal to the wrist crease when using low frequency probes (< 15 MHz) and at the wrist crease, proximal to the wrist crease, proximal forearm and the distal upper arm in Asians. CSA values were lower when in flexed position compared to extended position for the cubital tunnel inlet only. No difference was found for gender.

CONCLUSIONS

Our systematic review provides a comprehensive set of normal values at sites along the entire length of the ulnar nerve. This provides a foundation for clinical practise and upon which future studies could be more systematically compared.

Interpretation of Electrodiagnostic Studies: How to Apply It to the Practice of Orthopaedic Surgery

Electrodiagnostic studies may help orthopaedic surgeons to identify and confirm nerve pathology, determine severity of disease, localize the lesion, identify concomitant or alternative pathology, and prognosticate potential outcomes with nonoperative or operative treatment. Surgeons should recognize the indications for electrodiagnostic studies, principles of their performance, and how to assess the primary data generated by the examination and how it can inform their treatment plans.

A simple test to assist with the diagnosis of common fibular nerve entrapment and predict outcomes of surgical decompression

BACKGROUND

Common fibular (peroneal) nerve (CFN) entrapment is the most frequent nerve entrapment in the lower extremity. It can cause pain, sensory abnormalities, and reduced ability to dorsiflex the foot or a drop foot. A simple test to assist with diagnosis of CFN entrapment is described as an adjunctive clinical tool for the diagnosis of CFN entrapment and also as a predictor of successful surgical decompression of a CFN entrapment.

METHODS

The test, a lidocaine injection into the peroneus longus muscle at the site of a common fibular nerve entrapment, was studied retrospectively in 21 patients who presented with a clinical suspicion of CFN entrapment. Patients ages ranged from 17 to 71 (mean 48.5).

RESULTS

The lidocaine injection test (LIT) was positive in 19 patients, and of these, 17 underwent surgical decompression and subsequently experienced improved ability to dorsiflex their foot and reduced sensory abnormalities.

CONCLUSION

The LIT is a simple, safe adjunctive test to help diagnose and also predict a successful outcome of surgical decompression of a CFN entrapment. The proposed mechanism of action of the LIT could lead to new, non-surgical treatments for CFN entrapment.

Paracetamol 325 mg/tramadol 37.5 mg effect on pain during needle electromyography: a double-blind crossover clinical trial

Needle insertion during electromyography (EMG) may cause varying levels of pain that could lead to inaccurate assessment and premature termination of the procedure. The aim of this study is to compare paracetamol 325 mg/tramadol 37.5 mg with placebo in relieving pain before EMG. This is a randomized, crossover, placebo-controlled, double-blind clinical trial; forty-four healthy individuals, including 27 males with a mean age of 35.3 years (range 18-59 years), entered this study. The needles were inserted unilaterally 2 h after administration of two analgesic tablets of paracetamol 325 mg/tramadol 37.5 mg or two placebo tablets. The pain was scored through a 100-mm visual analog scale (VAS) immediately and 2 h after the procedure. The side effects were also recorded. Within a week, the procedure was repeated on the other upper limb, changing the treatment and placebo. The immediate and 2-h VAS scores were notably lower after administration of treatment compared to placebo (immediate pain: 17.5 ± 12.8 vs. 32.1 ± 16.0, P < 0.001; and 2-h pain: 1.6 ± 5.6 vs. 5.8 ± 7.9, P = 0. 002). There was a higher prevalence of side effects when treatment was used (48 vs. 9 %, P < 0.001). Although most symptoms were mild, transient and resolved without medical interventions, on one occasion a volunteer experienced brief loss of consciousness and one subject had severe vertigo that required hospitalization and fluid therapy. Paracetamol 325 mg/tramadol 37.5 mg administration prior to EMG could effectively alleviate pain. Further application of this medication in patients with neuromuscular disorders would warrant additional clinical trials, particularly considering the adverse events.

Perception of pain during electromyography in children: A prospective study

INTRODUCTION

Electrodiagnostic examination is perceived as a painful examination. An accurate assessment of its discomfort would be valuable to children, their parents, and clinicians.

METHODS

We performed a prospective study of pediatric patients seen over 3 months at 1 center. Pain was scored for both nerve conduction studies and needle electromyography (EMG) on validated scales, depending on the child's age and in comparison with venipuncture.

RESULTS

In 100 cases the pain recorded fell within the moderate range on the scoring systems used. Sixty-six percent of patients described the pain to be equivalent or less than that with venipuncture. EMG of > 1 muscle or a proximal muscle produced more pain in patients <4 years of age.

CONCLUSIONS

When discussing the test with patients, the physician should reassure the patient and parents regarding the degree of pain that may be encountered, which is not materially different from venipuncture. Muscle Nerve 54: 422-426, 2016.

Resident Accuracy of Electromyography Needle Electrode Placement Using Ultrasound Verification

BACKGROUND

Electromyography (EMG) and musculoskeletal (MSK) ultrasound (US) are core learning objectives during physical medicine and rehabilitation (PM&R) training. However, there have been no prior studies using MSK US to assess the acquisition of EMG procedural skills during residency training. This study aims to demonstrate the differences in skillful needle placement between junior and senior physiatry residents. The integration of both EMG and MSK US may have tremendous potential for additional learning opportunities related to electrodiagnostic education.

OBJECTIVE

To determine the accuracy of anatomic landmark-guided EMG needle electrode placement in commonly used muscles by PM&R resident physicians.

DESIGN

Cross-sectional study.

SETTING

An academic PM&R residency program.

PARTICIPANTS

Twelve (5 postgraduate year [PGY] -3 and 7 PGY-4) PM&R resident physicians participating in a MSK US training course.

METHODS

Twelve PM&R residents in the eighth month of their third and fourth years of postgraduate training performed anatomic landmark-guided needle placement to the extensor indicis proprius (EIP), pronator teres (PT), peroneus longus (PL), and soleus muscles of live subjects. Once the needle electrode was satisfactorily placed, needle localization was verified with US.

MAIN OUTCOME MEASURES

Accuracy of EMG needle electrode placement.

RESULTS

The overall accuracy of needle electrode placement for all resident participants was 68.8%. The mean accuracy of the 4 selected muscles was 50% by PGY-3 residents and 82.1% for PGY-4 residents (P = .01). EIP was the most commonly missed muscle, with correct placement performed by 20% of PGY-3 and 42.9% of PGY-4 residents. PGY-3 residents demonstrated 60% accuracy with localizing the PT, PL, and soleus muscles. PGY-4 residents demonstrated 85.7% accuracy for PT, and 100% accuracy for both PL and soleus muscles.

CONCLUSIONS

Senior residents demonstrated greater accuracy of landmark-guided needle placement than junior residents. EMG procedural skills are important milestones in PM&R training, and MSK US may be a useful tool to enhance resident learning.