How does the correction in lumbar lordosis affect the spinopelvic realignments in degenerative lumbar scoliosis underwent scoliosis surgery?

Abstract

Background: To evaluate the effects of correction in lumbar lordosis (LL) that have on full-body realignments in patients with degenerative lumbar scoliosis (DLS) who had undergone long sacroiliac fusion surgery.

Methods: A multi-center retrospective study including 88 DLS patients underwent the surgical procedure of long sacroiliac fusion with instrumentations was performed. Comparisons of radiographic and quality-of-life (QoL) data among that at the pre-operation, the 3rd month and the final follow-up were performed. The correlations between the LL correction and the changes in other spinopelvic parameters were explored using Pearson-correlation linear analysis and linear regression analysis. The correlation coefficient (r) and the adjusted r² were calculated subsequently.

Results: All radiographic and QoL data improved significantly (P < 0.001) after the surgical treatments. The LL correction correlated (P < 0.001) with the changes in the sacral slope (SS, r = 0.698), pelvic tilt (PT, r = -0.635), sagittal vertical axis (SVA, r = -0.591), T1 pelvic angle (TPA, r = -0.782), and the mismatch of pelvic incidence minus lumbar lordosis (PI-LL, r = -0.936), respectively. Moreover, LL increased by 1° for each of the following spinopelvic parameter changes (P < 0.001): 2.62° for SS (r² = 0.488), -4.01° for PT (r² = 0.404), -4.86° for TPA (r² = 0.612), -2.08° for the PI-LL (r² = 0.876) and -15.74 mm for SVA (r² = 0.349). Changes in the thoracic kyphosis (r = 0.259) and pelvic femur angle (r = 0.12) were independent of the LL correction, respectively.

Conclusions: LL correction correlated significantly to the changes in spinopelvic parameters; however, those independent variables including the thoracic spine and hip variables probably be remodeled themselves to maintain the full-body balance in DLS patients underwent the correction surgery.

Keywords: Degenerative lumbar scoliosis; Lumbar lordosis; Quality of life; Spinopelvic alignment.

Fig. 1

Schematic drawing of spinopelvic and hip parameters

Fig. 2

Scatterplots reveal the significant relationships between the correction in lumbar lordosis and the changes in other radiographic parameters. d-indicates the perioperative changes; LL lumbar lordosis, TK thoracic kyphosis, SS sacral slope, PT pelvic tilt, PI–LL the mismatch of pelvic incidence minus lumbar lordosis, PFA pelvic femur angle, SAA sagittal acetabular anteversion, SVA sagittal vertical axis, TPA T1 pelvic angle

Fig. 3

A 68-year-old male DLS patient underwent lumbar fusion surgery (L1–S1). Radiographs show the changes in spinopelvic parameters, preoperative TK, LL, PT, SS, PI, PFA, SAA, SVA and TPA were 6.6°, −15.8°, 26.6°, 25.4°, 52.0°, 200.0°, 36.0°, 2.6 mm and 17.7°, respectively (A). Postoperatively, those variables were 14.7° for TK, −41.1° for LL, 18.8° for PT, 34.1° for SS, 52.9° for PI, 185.4° for PFA, 35.9° for SAA, −27.3 mm for SVA, and 8.7° for TPA (B). At the final follow-up, those variables were 15.8° for TK, −41.2° for LL, 18.9° for PT, 38.9° for SS, 57.8° for PI, 189.6° for PFA, 36.2° for SAA, 17.8 mm for SVA, and 14.6° for TPA (C). The PI–LL was 36.2°, 11.8° and 16.6° at the pre-, post-operation and the final follow-up, respectively

Fig. 4

A 58-year-old female DLS patient underwent thoracolumbar fusion surgery (T10–S2). Radiographs show the changes in spinopelvic parameters, preoperative TK, LL, PT, SS, PI, PFA, SAA, SVA and TPA were 16.9°, −16.9°, 27.5°, 4.2°, 31.7°, 197.2°, 51.0°, −4.3 mm and 19°, respectively (A). Postoperatively, those variables were 37.6° for TK, -35.8° for LL, 20° for PT, 15.3° for SS, 35.3° for PI, 193.7° for PFA, 49.2° for SAA, −21.5 mm for SVA, and 14° for TPA (B). The PI–LL postoperatively was -0.5° at the post-operation. The patient has a significant upright posture after the surgery (B); however, PJF developed at the 18^th month during follow-up (C)

Fig. 5

A 68-year-old female DLS patient underwent thoracolumbar fusion (T10–S2) surgery. Radiographs show the changes in spinopelvic parameters, preoperative TK, LL, PT, SS, PI, PFA, SAA, SVA and TPA were 11.3°, −7.3°, 27.3°, 20.9°, 48.2°, 206.4°, 52.0°, 90.7 mm and 29°, respectively (A). Postoperatively, those variables were 20.3° for TK, −25.1° for LL, 24.7° for PT, 21.8° for SS, 49.5° for PI, 193.8° for PFA, 50.3° for SAA, 15.3 mm for SVA, and 26.2° for TPA (B). The PI–LL was 24.8° at the post-operation. However, the patient had intermittent back pain after surgery, and PJK developed at the 4^th month during follow-up (C)