Preoperative Neurological and Neurophysiological Assessment of Patients with Idiopathic Scoliosis Treated or Not Treated with Physiotherapy: A Retrospective Comparative Study

Background/Objectives: The aim of this study was to precisely characterize neurological deficits in patients with idiophatic scoliosis (IS) by comparing preoperative clinical and neurophysiological examination results in patients with Lenke 1 and 3 spinal curvatures. Bracing alone (NTP) is commonly applied preoperatively in subjects with IS, but incorporating the concept of prerehabilitation with additional physiotherapy (TP) may further slow the progression of scoliosis. Methods: An interview regarding the development and conservative treatment of IS, clinical neurological assessment, and bilateral neurophysiological tests involving electromyography (sEMG) of motor unit activity in the paraspinal and lower extremity muscles, electroneurography (ENG) of neural impulse transmission in the peroneal nerve motor fibers and entire efferent conduction involving recordings of motor evoked potentials (MEPs) induced with transcranial magnetic field stimulation (TMS) were performed in patients with Lenke 1 (N = 33) and Lenke 3 (N = 27) spine curvatures in two groups (N = 30 each) that were treated (TP) or not treated (NTP) with physiotherapy. Results: Back pain, assessed on the VAS by all Lenke 3 patients, was 3.3 on average. Limited spine mobility (p < 0.001) was not associated with better results following physiotherapeutic treatment in either Lenke patient group. Sensory perception studies within the L3–S1 dermatomes and vibration sensation tests were found to be slightly decreased in Lenke 3 patients (p < 0.001), predominantly on the concave IS side, but less so in the TP group. Achilles tendon and patellar reflexes were detected as pathological (p < 0.001) only in Lenke 3 patients, and less frequently in the TP group. Asymmetry on the concave side of scoliosis in manual muscle testing scores was found (p < 0.001) in Lenke 3 patients, showing moderate muscle weakness in the distal lower extremities, mainly in the NTP group. sEMG recordings from the paraspinal muscles revealed moderate neurogenic abnormality that was more intense on the concave side of scoliosis curvature, both main and second; the pattern of muscle motor unit activity in the proximal and distal muscles of the lower extremities was consistent with the muscle strength deficits observed in manual muscle testing, though less so in the TP group. Deficits in MEP amplitudes recorded from lower extremity muscles and the peroneal nerve were found to be more commonly expressed on the concave side of the main scoliosis curvature and on the concave side of the second scoliosis curvature, particularly in Lenke 3 patients, but the significance of changes was lower in the TP group (p = 0.03–0.009). ENG studies showed moderate abnormalities in peripheral neural conduction of peroneal nerve motor fibers originating at the L5 ventral root, especially in Lenke 3 patients from the NTP group. Conclusions: Neurological diagnostic tests, supported by selected clinical neurophysiological studies, reveal greater motor and sensory abnormalities in IS patients with Lenke 3 than with Lenke 1 curvatures. The study indicates that patients in both groups who received only bracing had poorer outcomes than those who received additional physiotherapy. In the context of prerehabilitation, a combined conservative treatment approach including physiotherapy can provide functional benefits for the IS patient before the necessary surgical treatment. In this study, differences were observed between the groups treated with physiotherapy and those not treated; however, a causal link cannot be established. The results are consistent with a possible benefit of the physiotherapy, but they require further prospective studies to be proven.