Tag: lumbar spinal canal stenosis

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The Mechanism of Ligamentum Flavum Hypertrophy

Ligamentum Flavum Hypertrophy

Neurosurgery 77:274–282, 2015

Biochemical alterations associated with mechanical stress have been explored as an initiating step in the pathological progression of ligamentum flavum hypertrophy (LFH); however, this mechanism remains poorly understood. Recently, the inflammation induced after mechanical stress and the subsequent response of ligamentum flavum (LF) cells have been implicated in LFH pathology.

OBJECTIVE: To investigate the hypothesis that angiogenesis may be a critical link between hypertrophy and a series of stimulating events, including mechanical stress.

METHODS: LF from 20 lumbar spinal canal stenosis (LSCS) patients and 16 non-LSCS patients (control group) were collected during surgery. Patient demographic and radiographic data were obtained. The levels of angiogenic factors (vascular endothelial growth factor [VEGF], angiopoietin-1, vascular cell adhesion molecule, and basic fibroblast growth factor) in the LF were investigated by using an enzyme-linked immunosorbent assay. Angiogenesis was also quantified by immunohistochemical detection of CD34-positive capillaries. The correlations among clinical factors, including radiographic factors, angiogenic factors, and angiogenesis, were statistically analyzed.

RESULTS: The LSCS group was older and exhibited a longer symptom duration, wider segmental motion, and thicker LF than the control group. The LSCS group showed significantly higher tissue concentrations of VEGF (P , .001) that positively correlated with LF thickness (r = 0.557, P , .001) and segmental motion (r = 0.586, P , .001). The LSCS group showed significantly more CD34-positive capillaries than the control group (P = .004).

CONCLUSION: The LSCS group showed greater segmental motion, higher VEGF concentrations, and more CD34-positive capillaries than the control group. These data indicate that VEGF-mediated angiogenesis following mechanical stress may be a critical step within the series of pathological events in LFH.

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Axial Loading During Magnetic Resonance Imaging in Patients With Lumbar Spinal Canal Stenosis

SPINE Volume 37, Number 16, pp E-985–E992

We compared the sizes of the dural sac among conventional magnetic resonance imaging (MRI), axial loaded MRI, and upright myelography in patients with lumbar spinal canal stenosis (LSCS).

Objective. To determine whether axial loaded MRI can demonstrate similar positional changes of the dural sac size as were detected by upright myelography in LSCS.

Summary of Background Data. In patients with LSCS, constriction of the dural sac is worsened and symptoms are aggravated during standing or walking. To disclose such positional changes, upright myelography has been widely used. Recently, axial loaded MRI, which can simulate a standing position, has been developed. However, there has been no study to compare the dural sac size between axial loaded MRI and upright myelography.

Methods. Forty-four patients underwent conventional MRI, axial loaded MRI, and myelography. Transverse and anteroposterior diameters and the cross-sectional areas of the dural sac from L2– L3 to L5–S1 were compared. Pearson correlations of the diameters between the MRIs and the myelograms were analyzed. On the basis of the myelograms, all disc levels were divided into severe and nonsevere constriction groups. In each group, the diameters and the cross-sectional areas were compared. Sensitivity and specifi city to detect severe constriction were calculated for the conventional and axial loaded MRI.

Results. Transverse and anteroposterior diameters at L4–L5 in the axial loaded MRI and myelogram were signifi cantle smaller than those observed in the conventional MRI ( P < 0.001). Crosssectional areas in the axial loaded MRI were signifi cantly smaller than those in the conventional MRI at L2–L3, L3–L4, and L4–L5 ( P < 0.001). Between the axial loaded MRI and the myelography, Pearson correlation coeffi cients of the transverse and anteroposterior diameters were 0.85 and 0.87, respectively ( P < 0.001), which were higher than those for conventional MRI. Reductions of the dural sac sizes in the axial loaded MRI were more evident in the severe constriction group. The axial loaded MRI detected severe constriction with a higher sensitivity (96.4%) and specifi city (98.2%) than the conventional MRI.

Conclusion. The axial loaded MRI demonstrated a significant reduction in the dural sac size and signifi cant correlations of the dural sac diameters with the upright myelogram. Furthermore, the axial loaded MRI had higher sensitivity and specifi city than the conventional MRI for detecting the severe constriction observed in the myelogram. Therefore, the axial loaded MRI can be used to represent positional changes of the dural sac size detected by the upright myelography in patients with LSCS.

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Total Sagittal Spinal Alignment in Patients With Lumbar Canal Stenosis Accompanied by Intermittent Claudication

Spine 2010;35:E344–E346

Study Design. Cross-sectional study of total sagittal spinal alignment in lumbar spinal canal stenosis (LCS) patients with and without intermittent claudication.

Objective. To evaluate total sagittal spinal alignment in LCS. Summary of Background Data. The sagittal spinal alignment is an important factor in the management of lumbar degenerative diseases and lower back pain. Patients with LCS accompanied by intermittent claudication adopt a forward-bending posture during walking. However, few studies have quantitatively assessed the abnormal posture in LCS in relation to clinical symptoms.

Methods. This study analyzed 93 patients with LCS. They were divided into two groups according to the presence of neurogenic intermittent claudication; patients of the Claudicant group had intermittent claudication of the cauda equina (n  53; mean age, 66.7) and those of the Nerve root group had no claudication (n  40; mean age, 67.0). The following parameters were measured on the lateral whole-spine standing radiographs: the distance between the C7 plumb line and the posterior superior corner on the superior margin of S1 (sagittal vertical axis), the angle between the superior margin of the first lumbar vertebra and the first sacral vertebra (L1S1), lumbar lordotic angle, pelvic tilting angle (PA), and pelvic morphologic angle (PRS1).

Results. The sagittal vertical axis of the Claudicant group (57.6  37.5 mm) was significantly larger than that of the Nerve root group (40.3  42.3 mm) and was larger in both groups compared with the standard values. Lumbar lordotic angle was smaller (18.8°  13.2°) and pelvic tilting angle was larger (27.2°  8.3°) in patients with the Claudicant group than those with the Nerve root group (22.4°  14.0° and 22.7°  7.2°, respectively).

Conclusion. Patients of the Claudicant group exhibited forward bending of the trunk and pelvis backtilt, compared with those of the Nerve root group.


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