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.
- SourceAvailable from: Thiru M Annaswamy[Show abstract] [Hide abstract]
ABSTRACT: Degenerative processes can cause chronic low back pain, occasionally causing impingement of the lumbar dorsal rami resulting in a clinical syndrome previously described as lumbar dorsal ramus syndrome (LDRS). To evaluate the clinical basis of LDRS by comparing pain, disability and objective measures of pathophysiology in 3 groups of subjects defined by needle electromyography (NEE) findings. Prospective group cohort study with retrospective chart review SETTING: Veterans Affairs medical center outpatient clinic PATIENTS: Subjects who had undergone lower limb NEE and lumbar magnetic resonance imaging (MRI). 71 subjects' records meeting the study criteria were retrospectively reviewed for interventional spine procedures performed and to measure the lumbosacral paraspinal cross-sectional area (PSP CSA). 28 of the 71 subjects had further clinical assessment. One-way ANOVA was performed to evaluate group differences. Retrospective arm: 1) CSA of PSP were measured at 4 lower lumbar disk levels (average of 3 consecutive slices/level) bilaterally and overall left and right lumbar average PSP CSA and 2) the frequency & type of interventional spine procedures performed. Prospective arm: 1) temporal changes of NEE abnormalities, 2) pain measured using visual analog scale, 3) pain disability questionnaire and 4) short-form 36 scores. Right L5 CSA was significantly greater in the mechanical low back pain (LBP) compared to the lumbar radicular syndrome (LRS) group (F=3.3; p<.05). There were no significant group differences in the number of spine procedures performed. There were no significant differences in pain or disability scores among the groups. NEE findings improved over time predominantly in the LDRS group. LDRS is a diagnosis with identifiable NEE (lumbar multifidus denervation) findings and MRI findings that may include lower lumbar paraspinal atrophy. NEE (paraspinal denervation) findings in LDRS may change over time and the clinical relevance of LDRS to pain, functional disability and treatment response is unclear.PM&R 08/2013; · 1.37 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Assessment of the integrity of the multifidus muscles and corresponding nerve roots, post-open (OSS) versus minimally invasive spinal surgery (MISS) for lumbar spine fractures. We investigated the first six patients undergoing MISS in our institution and age- and sex-matched them with 6 random patients who previously had OSS. All had a similar lumbar fracture configuration without evidence of spinal cord injury. All were assessed using ultrasound muscle quantification and electromyographic studies at a minimum of 6 months post-operatively. Mean cross-sectional area (CSA) was measured at sequential levels within and adjacent to the operative field. Concentric needle electromyography was performed at instrumented and adjacent non-instrumented levels in each patient. Mean CSA across all lumbar multifidus muscles was 4.29 cm(2) in the MISS group, 2.26 cm(2) for OSS (p = 0.08). At the instrumented levels, mean CSA was 4.21 cm(2) for MISS and 2.03 cm(2) for OSS (p = 0.12). At non-instrumented adjacent levels, mean CSA was 4.46 cm(2) in the MISS group, 2.87 cm(2) for OSS (p = 0.05). Electromyography at non-instrumented adjacent levels demonstrated nerve function within normal limits in 5/6 levels in the MISS group compared to 1/6 levels in the OSS (p = 0.03). Instrumented levels demonstrated nerve function within normal limits in 5/12 levels in the MISS group compared with 4/12 in the OSS group, including moderate-severe denervation at 5 levels in the OSS group (p = 0.15). Posterior instrumented MISS demonstrates a significantly superior preservation of the medial branch of the posterior ramus of the spinal nerve and less muscle atrophy, particularly at adjacent levels when compared to OSS.European Spine Journal 08/2013; · 2.13 Impact Factor
- [Show abstract] [Hide abstract]
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; · 1.55 Impact Factor