Analysis of Lumbar Sagittal Curvature in Spinal Decompression and Fusion for Lumbar Spinal Stenosis Patients under Roussouly Classification

Abstract

To evaluate the clinical significance of spinal decompression and fusion for lumbar spinal stenosis in old patients under Roussouly classification, 160 old patients (>60 year old) with lumbar spinal stenosis underwent spinal decompression, and fusion were retrospectively studied. According to Roussouly classification, patients were divided into 4 groups, in which Roussouly types I, II, and IV were the nonstandard group and Roussouly type III was the standard group. Visual analog scale (waist, leg) and Oswestry disability index (ODI) scores were recorded before operation and at the final follow-up. All patients improved the sagittal curvature: for patients in Roussouly types I and II, there were statistically significant differences in terms of postoperative global lordosis (GL), global kyphosis (GK), sacral slope (SS), sagittal vertical axis (SVA), and pelvic tilt (PT) compared with that before surgery (all P < 0.001); patients in Roussouly type IV obtained similar results with type III after surgery. The four groups showed significant improvement in ODI and VAS scores at final follow-up (all P < 0.001). After regrouping at the final follow-up, the proportion of the standard type (Roussouly type III) patients was increased compared with preoperative. In conclusion, Roussouly classification has important guiding significance in spinal decompression and fusion for old patients (>60 years) with lumbar spinal stenosis.

Figure 1

(a, b) Sagittal parameters of the spine under Roussouly classification: sagittal parameters of lumbar spine: inflection point (IP), lordosis tilt angle (LTA), apex (A), global lordosis (GL), lower arc (LA), and upper arc (UA); pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS); sagittal vertical axis (SVA); global kyphosis (GK).

Figure 2

Roussouly classification. A four-part classification of morphology was used to classify each patient (a–d).

Figure 3

A 60-year-old male with diagnosed with lumbar spinal stenosis and had back pain for 4 years, aggravating pain in both lower limbs for 6 months. (a) Preoperative X-ray showed SVA = 20.4 mm, SS = 32.7, Roussouly type I, with the apex of lordosis at L5 upper edge, GL = 47.7°, PI = 60.8°, PT = 26.6°, SS = 32.7°, GK = 40.7°. (b) Preoperative lumbar CT and MRI showed L3/4, L4/5 segment disc herniation, facet joint hyperplasia and cohesion, and dural compression. (c) Postoperative X-ray showed that SVA = 0 mm, SS = 44.0°, Roussouly type III, the lumbar lordosis vertex was at the L4 midpoint, GL = 55.7°, PI = 58.8°, PT = 16.5°, SS = 44.0°, and GK = 50.0°. SS, GL, and GK increased; SVA and PT decreased; PI unchanged. Lordosis vertex moved up to the L4 midpoint, classification from Roussouly types I to III (standard).

Figure 4

A 67-year-old male with diagnosed with lumbar spinal stenosis and had back pain for 3 years, with intermittent claudication. (a) Preoperative X-ray showed SVA = 46.3 mm, SS = 32, Roussouly type II, lumbar lordosis apex at L4 base, GL = 42.1°, PI = 39.0°, PT = 7.6°, SS = 32.0°, GK = 32.2°. (b) Preoperative lumbar CT and MRI showed L4/5 segment disc herniation, yellow ligament hypertrophic, dural compression, and spinal canal narrowing. (c) Postoperative X-ray showed that SVA = 10.4 mm, SS = 38.2°, Roussouly type III, the lumbar lordosis vertex was at the L4 midpoint, GL = 57.2°, PI = 5.4°, PT = 36.9°, SS = 38.2°, GK = 53.5°. SS, GL, and GK increased; SVA and PT decreased; PI unchanged. Lordosis vertex moved up to the L4 midpoint, classification from Roussouly types II to III (standard).