Paraspinal mapping: Quantified needle electromyography in lumbar radiculopathy
ABSTRACT In the diagnosis of low back pain, the presence of a high percentage of false positive findings on radiologic imaging studies has lead to a more definitive role for electrodiagnosis as a confirmatory test. The paraspinal muscles are a crucial part of the electrodiagnostic examination for radiculopathy. To date, no technique for paraspinal evaluation has been validated. Based on previously documented anatomical techniques, we have designed a method of paraspinal examination termed "paraspinal mapping" (PM). Electromyographic (EMG) needles are placed in five carefully chosen locations and inserted in multiple directions. Individual scores for these insertions are added to determine a total PM sensitivity score. The first 50 studies using PM were compared to peripheral EMG, imaging studies, and pain drawings. Results indicate that the technique is easy to perform. Sensitivity scores relate well with these tests. In this limited and uncontrolled population, PM had higher sensitivity for abnormalities than either peripheral EMG or imaging studies. Because of the anatomical validity of PM, future studies may show it to be useful in localizing the level of radiculopathy independently from peripheral EMG, and to support clinical findings and imaging studies.
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ABSTRACT: Different studies have shown that atrophy of paraspinal muscles arises after open dorsal lumbar fusion, and the reasons for this atrophy are still not yet fully clarified. This prospective study investigates the extent of atrophy of the lumbar paraspinal muscles after open lumbar interbody fusion, its possible causes, and their association with clinical outcome measures. Thirty consecutive patients were prospectively included (13 male, 17 female, median age 60.5 years, range 33-80 years). Mono or bisegmental, posterior lumbar interbody fusion and instrumentation was performed applying a conventional, open lumbar midline approach. Clinical outcome was assessed by the Short Form (36) Health Survey (SF-36) questionnaire and visual analogue scale. Needle electromyography of paraspinal muscles was performed preoperatively, at 6 and 12 months. Serum values of creatine kinase, lactate dehydrogenase and myoglobin were determined preoperatively, at day 2 after surgery and at discharge. Paraspinal muscle volume was determined by volumetric analysis of thin-slice computed tomography scans preoperatively and 1 year after surgery. There was a significant increase of electromyographic denervation activity (p =0.024) and reduced recruitment of motor units (p = 0.001) after 1 year. Laboratory studies showed a significant increase of CK (p < 0.001) and myoglobin (p < 0.001) serum levels at day 2 after surgery. The paraspinal muscle volume decreased from 67.8 to 60.4 % (p < 0.001) after 1 year. Correlation analyses revealed a significant negative correlation between denervation and muscle volume (K = -0.219, p = 0.002). Paraspinal muscle volume is significantly correlated with physical outcome (K = 0.169, p = 0.020), mental outcome (K = 0.214, p = 0.003), and pain (K = 0.382, p < 0.001) after 1 year. Atrophy of paraspinal muscles after open, posterior lumbar interbody fusion seems to be associated with denervation, as well as direct muscle trauma during surgery. While muscle atrophy is also correlated with a worse clinical outcome, it seems to be a determining factor for successful lumbar spine surgery.Acta Neurochirurgica 01/2014; 156(2). DOI:10.1007/s00701-013-1981-9 · 1.79 Impact Factor
PM&R 10/2014; 6(10):945-50. DOI:10.1016/j.pmrj.2014.09.010 · 1.66 Impact Factor
Article: LUMBOSACRAL RADICULOPATHY SCREEN[Show abstract] [Hide abstract]
ABSTRACT: The literature is unclear as to which muscles and how many are required for a sensitive lumbosacral radiculopathy (LSR) screen. A retrospective study of 247 electrodiagnostically confirmed LSRs in 201 patients over a 3-yr period was conducted to determine how many muscles were required to identify a LSR. All LSRs showed abnormal spontaneous activity (positive waves or fibrillation potentials) in two or more muscles innervated by the same nerve root level but different peripheral nerves. All cases were categorized by radiculopathy level, and the most frequently abnormal individual muscles were combined into different muscle screens. The frequency with which each muscle screen identified a radiculopathy was the frequency with which one or more muscles in the screen displayed abnormal spontaneous activity divided by the total number of radiculopathies. The paraspinal muscles (PM) alone identified 88% of LSRs. Without PM, two muscle screens identified only 14-68%, three muscle screens identified 37-89% and four muscle screens identified 45-92%. Including PM, three muscle screens identified 86-94% of LSRs, four muscle screens identified 91-97% and five muscle screens yielded 94-98% identification. Seven to ten muscle screens resulted in minimal improvements in identifying a LSR with 98-99% identification. We conclude that five muscle LSR screens, including PM, are sufficient to identify LSRs while minimizing patient discomfort and examiner time.American Journal of Physical Medicine & Rehabilitation 01/1994; 73(6):394-402. DOI:10.1097/00002060-199411000-00004 · 2.01 Impact Factor