A Novel Method for the Quantitative Evaluation of Lumbar Spinal Stenosis

Abstract

Study design: A retrospective study of computed tomography (CT) myelographic images in patients with degenerative lumbar spinal stenosis (LSS). Objectives: To introduce a new technique for the quantitative evaluation of LSS. Background: Advances in hardware and software technology now permit inexpensive digitalization of radiological images, and enable methodologies for quantifying space available for neural elements in spinal canal. However, a valid method with quantitative evaluation of spinal stenosis in living patients has not been developed yet. Methods and materials: Preoperative CT myelographic scans of 50 patients with degenerative LSS were collected for retrospective investigation. The patients subsequently underwent lumbar decompressive surgery. They included scans from thoracic vertebra 12 (T12) to sacrum (S1), in which each segment was scanned through both the vertebral body and disk. All CT scan films were digitized using a high-resolution digital camera. ImageTool i software was used to measure three parameters: cross-sectional area of dural sac at disk level (A), crosssectional area of spinal canal at midpedicular level (B), and cross-sectional area of vertebral body (C). The dural sac canal ratio (DSCR) was calculated as A/BÂ100%. Low DSCR implied severe dural sac compression with a high degree of stenosis. The spinal canal vertebral ratio (CVR) was also calculated as B/CÂ100%. Low CVR implied a low baseline of canal capacity for neural elements. They were calculated from T12 to S1. Results: The study consisted of 26 male and 24 female patients, with an average age of 68.4 (35-97) years. A total of 295 segments were evaluated, of which 118 (40%) were surgically decompressed. There were wide ranges of canal crosssectional areas (140-475 mm 2 ) and dural sac crosssectional area (54-435 mm 2 ). Male patients had a slightly larger canal cross-sectional area than female patients at each level. The mean CVR was found decreased from T12 (26.1%) to L4 (18.3%). This was higher in female than in male patients, especially from T12 to L2 (P < 0.01). There were significant correlations between spinal canal and dural sac cross-sectional area (r = 0.55, P < 0.001), and also between CVR and DSCR (r = 0.31, P < 0.001). Of the levels decompressed, 82% was performed from the level L2 to L5, in which there was no significant difference in canal cross-sectional area and CVR between decompression and nondecompression (P > 0.05). There was a good correspondence between decreasing mean DSCR and increasing percentile of levels decompressed. Conclusion: DSCR represents a useful method for the quantitative diagnosis of lumbar spinal canal stenosis. ImageTool i software is a useful tool in measuring spinal morphometry.

Degenerative lumbar spinal stenosis and lumbar spine configuration

“…Zheng et al [67] have revealed that the AP diameter of the spinal canal and the AP diameter of the vertebral body do not provide any evaluation in DLSS, contrary to the congenital type. Singh et al [9] characterized congenital stenosis through MR imaging and stated that the AP diameter of the spinal canal, pedicle length and vertebral body width were significantly smaller in the stenosis group, whereas no difference was found in the vertebral body AP diameter and body height, compared to the control.…”

Cauda equina redundant nerve roots are associated to the degree of spinal stenosis and to spondylolisthesis

“…First, related to the methodology, since the researchers measured stenosis via the anteroposterior diameter in the MRI and not via the dural sac CSA. The CSA measurements of the dural sac have previously been emphasised as the best option for studying spinal canal stenosis 18,19,20 . CSA measurements via MRI yield a high interobserver reproducibility 21 .…”

Post-Operative Complications in Patients Older than 60 Years Old with Lumbar Stenosis after Spinal Decompressive Surgery

“…The symptoms of spinal stenosis alone can be disabling, leading to physical deconditioning, loss of lean body mass, decreased cardiac and pulmonary functions, and depression. 15 Surgeons evaluating these patients must thus weigh the potential benefits of surgery against substantial medical comorbidities.…”

“…Improvements in ambulation were also demonstrated at rates similar to those in younger patients. 9,7,13,15 The increased risks of surgery must be discussed with the patient in the context of predicted functional gains. The strategies used in an attempt to minimize perioperative complications in all cases in which substantial blood loss is expected accurate accounts of intraoperative blood loss should be done and replaced.…”