STUDY DESIGN: A retrospective study. PURPOSE: To examine the effectiveness of using an electrodiagnostic technique as a new approach in the clinical diagnosis of extraforaminal stenosis at L5-S1. OVERVIEW OF LITERATURE: We introduced a new effective approach to the diagnosis of extraforaminal stenosis at the lumbosacral junction using the existing electrophysiological evaluation technique. METHODS: A consecutive series of 124 patients with fifth lumbar radiculopathy were enrolled, comprising a group of 74 patients with spinal canal stenosis and a second group of 50 patients with extraforaminal stenosis at L5-S1. The technique involved inserting a pair of needle electrodes into the foraminal exit zone of the fifth lumbar spinal nerves, which were used to provide electrical stimulation. The compound muscle action potentials from each of the tibialis anterior muscles were recorded. RESULTS: The distal motor latency (DML) of the potentials ranged from 11.2 to 24.6 milliseconds in patients with extraforaminal stenosis. In contrast, the DML in patients with spinal canal stenosis ranged from 10.0 to 17.2 milliseconds. After comparing the DML of each of the 2 groups and at the same time comparing the differences in DML between the affected and unaffected side of each patient, we concluded there were statistically significant differences (p<0.01) between the 2 groups. Using receiver operating characteristic curve analysis, the cutoff values were calculated to be 15.2 milliseconds and 1.1 milliseconds, respectively. CONCLUSIONS: This approach using a means of DML measurement enables us to identify and localize lesions, which offers an advantage in diagnosing extraforaminal stenosis at L5-S1.
Action Potentials ; Constriction, Pathologic* ; Diagnosis* ; Diagnostic Techniques and Procedures ; Electric Stimulation ; Electrodes ; Humans ; Muscles ; Needles ; Radiculopathy ; Retrospective Studies ; ROC Curve ; Spinal Canal ; Spinal Nerves ; Spinal Stenosis

Cross-sectional study.

Cross-sectional study.

Methods: LSS patients who underwent decompression surgery with or without fusion were included. Clinical outcomes were measured before surgery and 6 months postoperatively using the Zurich Claudication Questionnaire (ZCQ); Visual Analog Scale (VAS) of low back pain, leg pain, and leg numbness; Japanese Orthopaedic Association Back Pain Evaluation Questionnaire; and the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36). The Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale, and Pain Anxiety Symptoms Scale were used to evaluate psychological status before surgery. Patients were classified as satisfied or dissatisfied with surgery based on a ZCQ satisfaction subscale cutoff score of 2.5. Results: The satisfied and dissatisfied groups contained 128 and 29 patients, respectively. Six months postoperatively, outcome scores for the dissatisfied group were unchanged or worse than preoperative scores (p>0.05). Multivariate logistic regression analysis showed significant associations between dissatisfaction and preoperative low back pain VAS score ≥ median (odds ratio [OR], 0.27; 95% confidence interval [CI], 0.10–0.74; p=0.01), preoperative mental health SF-36 score ≥ median (OR, 0.26; 95% CI, 0.08–0.89; p=0.03), and preoperative anxiety HADS score ≥ median (OR, 3.95; 95% CI, 1.16–13.46; p=0.03). Conclusions Preoperative less severe low back pain, lower mental health, and higher anxiety are associated with patient dissatisfaction with lumbar surgery, not depression, pain catastrophizing, or fear-avoidance beliefs. Pre- and postoperative psychological status should be assessed carefully and managed appropriately.