Postoperative changes in sagittal spinopelvic alignment in sitting position in adolescents with idiopathic thoracic scoliosis treated with posterior fusion: an initial analysis

OBJECTIVE Previous studies have reported spinal straightening and pelvic retroversion when changing from erect to sitting posture in patients with adolescent idiopathic scoliosis (AIS), which were thought to be related to low-back pain after sitting for long periods. However, the sitting sagittal alignment after posterior spinal fusion has not been evaluated. This study aims to assess the influence of posterior fusion surgery upon sitting sagittal spinopelvic alignment in adolescents with idiopathic thoracic curves (thoracic AIS [T-AIS]). METHODS A total of 44 T-AIS patients (30 Lenke I and 14 Lenke II) from the authors' center were included in this study. Preoperative and postoperative long-cassette lateral radiographs of the spine and pelvis were obtained with the patients in standing and sitting positions. Thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured on standing and sitting lateral radiographs. Patients were divided into selective thoracic fusion (STF) and nonselective thoracic fusion (NSTF) groups. RESULTS At baseline, TK, LL, and SS decreased by 27.5%, 42.1%, and 31.1%, respectively, from the standing to the sitting position, while PT increased by 193.6%. After posterior spinal fusion, increased TK, LL, and SS and corresponding decreased PT were observed compared to baseline parameters in the sitting position. Comparison of postoperative sitting and standing values for the whole cohort showed that the mean LS and SS values were significantly lower in the sitting position (decreased by 14.0% and 13.9%, respectively, compared to standing), whereas the mean PT value was significantly greater (increased by 39.0%, compared to standing). Similar changes were also observed in the STF group: postoperatively the mean LL value was 15.6% lower in sitting than in standing, while the mean SS value was 11.5% lower. However, no obvious changes of the postoperative values in sitting were found in the NSTF group. CONCLUSIONS Nonselective thoracic fusion surgery in T-AIS patients diminished spinal straightening and pelvic retroversion during sitting. Reducing distal fusion levels was of special value in not only saving more lumbar mobility, but also preserving the function of pelvic posterior rotation.

Posterior corrective surgery with a multilevel transforaminal lumbar interbody fusion and a rod rotation maneuver for patients with degenerative lumbar kyphoscoliosis

The purpose of this study was to assess the clinical results of posterior corrective surgery using a multilevel transforaminal lumbar interbody fusion (TLIF) with a rod rotation (RR) and to evaluate the segmental corrective effect of a TLIF using CT imaging. The medical records of 15 consecutive patients with degenerative lumbar kyphoscoliosis (DLKS) who had undergone posterior spinal corrective surgery using a multilevel TLIF with an RR technique and who had a minimum follow-up of 2 years were retrospectively reviewed. Radiographic parameters were evaluated using plain radiographs, and segmental correction was evaluated using CT imaging. Clinical outcomes were evaluated with the Scoliosis Research Society Patient Questionnaire-22 (SRS-22) and the SF-36. The mean follow-up period was 46.7 months, and the mean age at the time of surgery was 60.7 years. The mean total SRS-22 score was 2.9 before surgery and significantly improved to 4.0 at the latest follow-up. The physical functioning, role functioning (physical), and social functioning subcategories of the SF-36 were generally improved at the latest follow-up, although the changes in these scores were not statistically significant. The bodily pain, vitality, and mental health subcategories were significantly improved at the latest follow-up (p < 0.05). Three complications occurred in 3 patients (20%). The Cobb angle of the lumbar curve was reduced to 20.3° after surgery. The overall correction rate was 66.4%. The pelvic incidence-lumbar lordosis (preoperative/postoperative = 31.5°/4.3°), pelvic tilt (29.2°/18.9°), and sagittal vertical axis (78.3/27.6 mm) were improved after surgery and remained so throughout the follow-up. Computed tomography image analysis suggested that a 1-level TLIF can result in 10.9° of scoliosis correction and 6.8° of lordosis. Posterior corrective surgery using a multilevel TLIF with an RR on patients with DLKS can provide effective correction in the coronal plane but allows only limited sagittal correction.

Selective versus nonselective thoracic fusion in Lenke 1C curves: a meta-analysis of baseline characteristics and postoperative outcomes

OBJECT

Lenke 1C curves are challenging to manage surgically due to the structural thoracic deformity and nonstructural lumbar curve. Selective thoracic fusion (STF) is considered the standard of care because it preserves motion of the lumbar segment, yet nonselective STF (NSTF) remains prevalent. This study aims to identify baseline patient characteristics that drive treatment and to compare postoperative outcomes for both procedures.

METHODS

Studies that compared baseline and postoperative demographic data, health-related quality of life (HRQL) questionnaires, and radiographic parameters of patients with Lenke 1C curves undergoing STF or NSTF were identified for meta-analysis. The effect measure is expressed as a mean difference (MD) with 95% CI. A positive MD signifies a greater STF value, or a mean increase within the group.

RESULTS

One prospective and 6 retrospective case-control studies with sample size of 488 patients (344 STF and 144 NSTF) were identified. Baseline age, sex, and HRQLs were equivalent, except for better scores in the STF group for the Scoliosis Appearance Questionnaire (SAQ): Unrelated to Deformity item (3.47 vs 3.88, p = 0.01) and the Spine Research Society questionnaire, Item 22: Pain (4.13 vs 3.92, p = 0.04). Radiographic findings were significantly worse in NSTF, as measured by the thoracolumbar/lumbar (TL/L) Cobb angle (MD: -4.29°, p < 0.01) and TL/L apical vertebral translation (AVT) (MD: -6.08, p < 0.01). Radiographic findings significantly improved in STF, as measured in the main thoracic (MT) Cobb angle (MD: -27.78°, p < 0.01), TL/L Cobb angle (MD: -16.24°, p < 0.01), MT:TL/L Cobb ratio (MD: -0.21, p < 0.01), coronal balance (MD: 0.47, p = 0.02), and thoracic kyphosis (MD: 7.87°, p < 0.01); and in NSTF in proximal thoracic (PT) Cobb angle (24° vs 14.1°, p < 0.01), MT Cobb angle (53.5° vs 20.5°, p < 0.01), and TL/L Cobb angle (41.6° vs 16.6°, p < 0.01). Postoperative TL/L Cobb angle (23.1° vs 16.6°, p < 0.01) was significantly higher in STF; but PT Cobb angle, MT Cobb angle, and MT:TL/L Cobb ratio are equivalent.

CONCLUSIONS

Patients with larger lumbar compensatory curves displaying a larger degree of coronal translation, as measured by the TL/L AVT, are more likely to undergo an NSTF. Contrary to established guidelines, larger MT curve magnitudes and MT:TL/L Cobb angle ratios have not been found to influence the decision to pursue a selective thoracic fusion. Although overall both STF and NSTF groups are found to have effective postoperative coronal balance, the STF group has only modest improvements in the lumbar curve position as determined by a relatively unchanged TL/L AVT. Furthermore, surgeons may prefer NSTF in patients who may have a worse overall perception of their spinal deformity as measured by HRQL measures of pain and desire for appearance change.