Spondylolisthesis Instability Research Articles

Intermodal Detection of Lumbar Instability in Degenerative Spondylolisthesis is Superior toFunctional Radiographs.

PurposeIn this study, we compare different imaging modalities to find the most sensitive and efficient way of detecting instability in lumbar spondylolisthesis.MethodsPatients presenting with spondylolisthesis from June 01, 2018 to May 31, 2020 with functional radiographs and either CT scans or MRI images were included in our single-center retrospective cohort study. The amount of translation, in millimeters, was measured on supine MRI images, CT scans, and radiographs of inclination while sitting, standing, or prone and reclination while standing using the Meyerding technique. The amount of translation was compared among the different modalities.ResultsA total of 113 patients with spondylolisthesis on 125 vertebral levels were included in this study. The mean patient age was 73.52 ± 12.59 years; 69 (60.5%) patients were females. The most affected level was L4/5 (62.4%), followed by L3/4 (16%) and L5/S1 (13.6%). The average translations measured on supine CT were 4.13 ± 5.93 mm and 4.42 ± 3.49 mm on MRI (p = 0.3 for the difference between MRI and CT). The difference of inclination while sitting radiograph to slice imaging was 3.37 ± 3.64 mm (p < 0.0001), inclination while standing to slice imaging was 2.67 ± 3.03 mm (p < 0.0001), reclination while standing to slice imaging was 1.6 ± 3.15 mm (p = 0.03), and prone to slice imaging was 2.19 ± 3.02 mm (p = 0.03).ConclusionWe found that a single radiograph in either inclination, reclination, or prone position compared to a CT scan or an MRI image in supine position can detect instability in spondylolisthesis more efficiently than comparison of functional radiographs in any position.

Spontaneous Reduction Finding: Magnetic Resonance Imaging Evaluation of Segmental Instability in Spondylolisthesis

Study DesignRetrospective chart review.PurposeTo assess whether spontaneous reduction of spondylolisthesis, as seen on magnetic resonance imaging (MRI), is related to the degree of segmental instability and low back pain.Overview of LiteratureThe flexion-extension radiographs obtained in the sagittal plane are frequently used when segmental instability of spondylolisthesis is evaluated.MethodsWe retrospectively reviewed 137 patients and measured the differences of the percentage of sagittal translation and sagittal angulation to determine the segmental instability between the flexion and extension radiographs, and the spontaneous reduction on MRI. We then compared the degrees of segmental instability and the degrees of spontaneous reduction. To assess the effect of low back pain on segmental motion in regards to the flexion-extension radiographs, we compared the preoperative visual analogue scales (VAS) score for low back pain between the more and the less spontaneous reduction groups.ResultsThe mean degree of spontaneous reduction was 5.2%. A statistically significant correlation was found between the sagittal translation on the flexion-extension radiographs and the degree of spontaneous reduction (r = 0.557, p < 0.001) and between the sagittal angulation on the flexion-extension radiographs and the degree of spontaneous reduction (r = 0.215, p = 0.012). The preoperative VAS scores for low back pain of the more spontaneous reduction group and the less spontaneous reduction group were 4.6 and 3.6 points, respectively, and this difference was statistically significant (p = 0.002).ConclusionsSpontaneous reduction of spondylolisthesis on MRI was found to be closely related to segmental instability, and the degree of spontaneous reduction seen on MRI could be useful for the evaluation of segmental instability in patients with spondylolisthesis, especially with severe low back pain.

En bloc partial laminectomy and posterior lumbar interbody fusion in foraminal spinal stenosis.

Study DesignA retrospective study.PurposeAn en bloc partial laminectomy and posterior lumbar interbody fusion (PLIF) in spinal stenosis patients with severe foraminal narrowing has a shorter operation time, less neural manipulation and allows indirect decompression by restoring the interforaminal height compared to other procedures. This study investigated the efficacy of the procedure.Overview of LiteraturePLIF is one of the most popular surgery for degenerative spine such as foraminal spinal stenosis, instability spondylolisthesis and discogenic pain. Various techniques for PLIF have their own advantages and disadvantages. But in some severe cases, we need an efficient method of PLIF for decompression and fusion.MethodsThis study examined 61 patients, who had 85 levels treated with PLIF using an en bloc partial laminectomy and facetectomy, and could be followed up for more than 2 years. The mean age of the patients and mean follow up period was 66 years and 39 months, respectively. The clinical results were evaluated using the MacNab's criteria, Visual Analogue Scale (VAS) score, and Korea Version Oswestry Disability Index (KODI). The union of the intervertebral space was evaluated using Lenke's criteria. The intervertebral angle and height of the posterior intervertebral disc were also measured.ResultsExcellent and good results were obtained in 54 cases (89%) according to MacNab's criteria. The VAS and KODI scores were 8.1 and 34.6, preoperatively, and 3.4, and 14.1, postoperatively. Bone union was A and B grades according to Lenke's criteria in 57 cases. The mean segmental angle and mean height of the posterior disc were respectively, 7.4° and 6.5 mm preoperatively, 9.1° and 10.6 mm postoperatively, and 8.0° and 9.7 mm in the last follow-up. There were 5 cases of postoperative infection, 4 cases of junctional problems and 1 case of screw malposition.ConclusionsEn bloc partial laminectomy and PLIF is an effective method for treating severe spinal stenosis with foraminal narrowing.

Vertical instability in spondylolisthesis: a traction radiographic assessment technique and the principle of management.

Lateral radiographs of the lumbar spine were taken of 40 patients with lumbar spondylolisthesis. These radiographs were taken in the neutral, flexion, and extension positions for both erect and recumbent postures, and also in the prone and supine positions with traction applied via a traction table. To define and demonstrate the presence of "vertical instability" in spondylolisthesis, and to determine the most useful radiographic views for clinical purposes and analysis of the surgical principle. Lateral radiographs of patients in flexion and extension are widely used to obtain quantitative and qualitative data on lumbar spondylolisthesis. Changes in lumbar disc height and segmental translation in a group of patients with spondylolisthesis have been demonstrated with the addition of traction and compression. Lateral and flexion extension radiographs of the lumbosacral spine in 37 patients with spondylolisthesis taken in standing and recumbent positions and under pelvic traction in the prone or supine positions were suitable for analysis. The changes in disc area, intervertebral kyphotic slip angle, and amount of anteroposterior shift (olisthesis) were measured from the radiographs using a computer digitizer. The disc area was normalized against the area of the superior vertebra, and the amount of anteroposterior shift was normalized against the anteroposterior width of the superior vertebra. Inter- and intraobserver error was found to be negligible, and results were analyzed by paired t test. Maximum slip angle, maximum olisthesis, and minimum normalized disc area were found with the subject under erect flexion. Conversely, prone traction and recumbent extension produced minimum slip angle, whereas the lowest anteroposterior shifts were seen with the subject under prone and supine traction. Prone traction also resulted in a significantly larger normalized disc area than any other posture. The change in kyphotic slip angle between erect flexion and prone traction is correlated with the change in normalized olisthesis and disc area. Erect flexion and prone traction radiographs represent the extremes of subluxation and reduction of the olisthesis, respectively, and the change in olisthesis seen between these extremes is correlated with the change in disc area and the intervertebral slip angle. Vertical laxity of the affected functional spinal unit resulting from disc degeneration produces laxity in the ligaments and disc anulus, allowing olisthetic motion. Restoration of disc height in turn restores tension to the soft tissues around the disc and results in a spontaneous reduction of the subluxation. Restoration and maintenance of disc height with a spacer or interbody fusion therefore is recommended as a goal in the treatment of spondylolisthesis. When spondylolytic spondylolisthesis involves a posterior column deficiency, additional reconstruction of this column with posterior instrumentation is recommended. Application of the traction radiographic technique in planning for spondylolisthesis reduction is discussed along with the technique of stabilization.

Vertical Instability in Spondylolisthesis

Study Design. Lateral radiographs of the lumbar spine were taken of 40 patients with lumbar spondylolisthesis. These radiographs were taken in the neutral, flexion, and extension positions for both erect and recumbent postures, and also in the prone and supine positions with traction applied via a traction table. Objectives. To define and demonstrate the presence of “vertical instability” in spondylolisthesis, and to determine the most useful radiographic views for clinical purposes and analysis of the surgical principle. Summary of Background Data. Lateral radiographs of patients in flexion and extension are widely used to obtain quantitative and qualitative data on lumbar spondylolisthesis. Changes in lumbar disc height and segmental translation in a group of patients with spondylolisthesis have been demonstrated with the addition of traction and compression. Methods. Lateral and flexion extension radiographs of the lumbosacral spine in 37 patients with spondylolisthesis taken in standing and recumbent positions and under pelvic traction in the prone or supine positions were suitable for analysis. The changes in disc area, intervertebral kyphotic slip angle, and amount of anteroposterior shift (olisthesis) were measured from the radiographs using a computer digitizer. The disc area was normalized against the area of the superior vertebra, and the amount of anteroposterior shift was normalized against the anteroposterior width of the superior vertebra. Inter- and intraobserver error was found to be negligible, and results were analyzed by paired t test. Results. Maximum slip angle, maximum olisthesis, and minimum normalized disc area were found with the subject under erect flexion. Conversely, prone traction and recumbent extension produced minimum slip angle, whereas the lowest anteroposterior shifts were seen with the subject under prone and supine traction. Prone traction also resulted in a significantly larger normalized disc area than any other posture. The change in kyphotic slip angle between erect flexion and prone traction is correlated with the change in normalized olisthesis and disc area. Conclusions. Erect flexion and prone traction radiographs represent the extremes of subluxation and reduction of the olisthesis, respectively, and the change in olisthesis seen between these extremes is correlated with the change in disc area and the intervertebral slip angle. Vertical laxity of the affected functional spinal unit resulting from disc degeneration produces laxity in the ligaments and disc anulus, allowing olisthetic motion. Restoration of disc height in turn restores tension to the soft tissues around the disc and results in a spontaneous reduction of the subluxation. Restoration and maintenance of disc height with a spacer or interbody fusion therefore is recommended as a goal in the treatment of spondylolisthesis. When spondylolytic spondylolisthesis involves a posterior column deficiency, additional reconstruction of this column with posterior instrumentation is recommended. Application of the traction radiographic technique in planning for spondylolisthesis reduction is discussed along with the technique of stabilization.

Association of incipient disc degeneration and instability in spondylolisthesis

The concurrence of early disc degeneration and abnormal segmental motion in spondylolysis of young low back pain patients (n = 14) was investigated using magnetic resonance imaging (MRI) and flexion-extension radiography. Seven patients with L5 spondylolisthesis had normal discs on MRI and 7 had disc degeneration below the slipped vertebra. The parallel motion, angular mobility and centre of motion were similar in the degenerated discs and in normal discs. The present study shows that in adolescents the motion pattern and hydration of discs associated with spondylolysis and spondylolisthesis are not always abnormal. The early dehydration and degeneration of lumbar discs observed on MRI are not always associated with abnormal mobility of the corresponding motion segment.