RESUMEN
OBJECTIVEThe purpose of this study was to determine the relationship between vertebral bodies, psoas major morphology, and the course of lumbar nerve tracts using diffusion tensor imaging (DTI) before lateral interbody fusion (LIF) to treat spinal deformities.METHODSDTI findings in a group of 12 patients (all women, mean age 74.3 years) with degenerative lumbar scoliosis (DLS) were compared with those obtained in a matched control group of 10 patients (all women, mean age 69.8 years) with low-back pain but without scoliosis. A T2-weighted sagittal view was fused to tractography from L3 to L5 and separated into 6 zones (zone A, zones 1-4, and zone P) comprising equal quarters of the anteroposterior diameters, and anterior and posterior to the vertebral body, to determine the distribution of nerves at various intervertebral levels (L3-4, L4-5, and L5-S1). To determine psoas morphology, the authors examined images for a rising psoas sign at the level of L4-5, and the ratio of the anteroposterior diameter (AP) to the lateral diameter (lat), or AP/lat ratio, was calculated. They assessed the relationship between apical vertebrae, psoas major morphology, and the course of nerve tracts.RESULTSAlthough only 30% of patients in the control group showed a rising psoas sign, it was present in 100% of those in the DLS group. The psoas major was significantly extended on the concave side (AP/lat ratio: 2.1 concave side, 1.2 convex side). In 75% of patients in the DLS group, the apex of the curve was at L2 or higher (upper apex) and the psoas major was extended on the concave side. In the remaining 25%, the apex was at L3 or lower (lower apex) and the psoas major was extended on the convex side. Significant anterior shifts of lumbar nerves compared with controls were noted at each intervertebral level in patients with DLS. Nerves on the extended side of the psoas major were significantly shifted anteriorly. Nerve pathways on the convex side of the scoliotic curve were shifted posteriorly.CONCLUSIONSA significant anterior shift of lumbar nerves was noted at all intervertebral levels in patients with DLS in comparison with findings in controls. On the convex side, the nerves showed a posterior shift. In LIF, a convex approach is relatively safer than an approach from the concave side. Lumbar nerve course tracking with DTI is useful for assessing patients with DLS before LIF.
RESUMEN
OBJECTIVE The aim of this study was to assess the usefulness of radiological parameters for surgical decision-making in patients with degenerative lumbar scoliosis (DLS) by comparing the clinical and radiological results after decompression or decompression and fusion surgery. METHODS The authors prospectively planned surgical treatment for 298 patients with degenerative lumbar disease between September 2005 and March 2013. The surgical method used at their institution to address intervertebral instability is precisely defined based on radiological parameters. Among 64 patients with a Cobb angle ranging from 10° to 25°, 57 patients who underwent follow-up for more than 2 years postoperatively were evaluated. These patients were divided into 2 groups: those in the decompression group underwent decompression alone (n = 25), and those in the fusion group underwent decompression and short segmental fusion (n = 32). Surgical outcomes were reviewed, including preoperative and postoperative Cobb angles, lumbar lordosis based on radiological parameters, and Japanese Orthopaedic Association (JOA) scores. RESULTS The JOA scores of the decompression group and fusion group improved from 5.9 ± 1.6 to 10.0 ± 2.8 and from 7.2 ± 2.0 to 11.3 ± 2.8, respectively, which was not significantly different between the groups. At the final follow-up, the postoperative Cobb angle in the decompression group changed from 14° ± 2.9° to 14.3° ± 6.4° and remained stable, while the Cobb angle in the fusion group decreased from 14.8° ± 4.0° to 10.0° ± 8.5° after surgery. CONCLUSIONS The patients in both groups demonstrated improved JOA scores and preserved Cobb angles after surgery. The improvement in JOA scores and preservation of Cobb angles in both groups show that the evaluation of spinal instability using radiological parameters is appropriate for surgical decision-making.
Asunto(s)
Descompresión Quirúrgica/métodos , Vértebras Lumbares/cirugía , Escoliosis/cirugía , Fusión Vertebral/métodos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
OBJECT: Spinal stenosis with degenerative lumbar scoliosis (DLS) mostly occurs in the elderly population (typically > 65 years old), causing pain in the legs and back, claudication, and spinal deformity. The surgical strategy for DLS is controversial concerning the surgical approach, fusion area, decompression area, correction methods, and ideal angle of curve correction. A nonfusion stabilization system with motion preservation has been recently used for degenerative spinal diseases with favorable outcomes. This study attempted to analyze surgical outcomes after decompression and nonfusion stabilization for spinal stenosis with a mild to moderate degree of DLS. METHODS: Twenty-eight patients (21 women and 7 men, with a mean age of 65.3 years) with spinal stenosis and DLS who underwent decompressive surgery and nonfusion stabilization with the Dynesys system were included in this study. Medical records and radiological studies were reviewed to access clinical and radiological outcomes and surgery-related complications. RESULTS: Fifty-nine segments were decompressed and stabilized without fusion in 28 patients, consisting of 1 segmental stabilization in 8 patients (28.6%, L4-5), 2 segmental stabilizations in 11 patients (39.3%, L3-5), 3 segmental stabilizations in 7 patients (25.0%, L2-5 in 6 patients, L3-S1 in 1 patient), and 4 segmental stabilizations in 2 patients (7.1%, L2-S1 in 1 patient, L1-5 in 1 patient). The mean follow-up period was 30.7 months. Radiologically, the mean lumbar scoliotic angle was 13.7° before surgery, 5.1° at 3 months postoperatively, 3.8° at 12 months postoperatively, 4.2° at 24 months postoperatively, and 3.9° at the last follow-up, which was statistically significant (p < 0.05). Lumbar lordosis and range of motion were preserved. The score on the visual analog scale for leg and back pain significantly decreased, and the Oswestry Disability Index significantly improved after surgery. There were no newly developed neurological deficits or aggravation of neurological symptoms. A radiolucent line around the pedicle screw was observed in 4 patients (14.2%) with 5 screws (2.8%). CONCLUSIONS: Adding nonfusion stabilization after decompressive surgery resulted in a safe and effective procedure for elderly patients with lumbar stenosis with a mild to moderate scoliosis angle (< 30°). Statistically significant improvement of the clinical outcome was obtained at the last follow-up evaluation with no progression of the degenerative scoliosis.