Factors favoring regain of the lost vertical spinal height through posterior spinal fusion in adolescent idiopathic scoliosis

Changes in height, weight, and body mass index after posterior spinal fusion in juvenile and adolescent idiopathic scoliosis

Purpose

Posterior spinal fusion for idiopathic scoliosis is known to increase spinal height, but the impacts on weight and resulting body mass index are unknown. This study assesses body mass index, weight, and height percentile changes over time after posterior spinal fusion for idiopathic scoliosis.

Methods

Body mass index, weight, and height age- and sex-adjusted percentiles for patients with idiopathic scoliosis undergoing posterior spinal fusion between January 2016 and August 2022 were calculated based on growth charts from the Centers for Disease Control for Disease Control and compared to preoperative values at 2 weeks, 3 months, 6 months, 1 year, and 2 years. The data were analyzed for normality with a Shapiro-Wilk test, and percentiles were compared with the Wilcoxon signed-rank tests.

Results

On average, 12.1 ± 2.3 levels were fused in 269 patients 14.4 ± 1.9 years, and percentiles for body mass index, weight, and height preoperatively were 55.5 ± 29.4%, 57.5 ± 28.9%, and 54.6 ± 30.4%, respectively. Body mass index and weight percentiles decreased at 2 weeks (-10.7%, p < 0.001; -4.6%, p < 0.001, respectively) and 3 months (-6.9%, p < 0.001; -3.2%, p < 0.001, respectively) postoperatively. Postoperative weight loss at 2 weeks averaged 2.25 ± 3.09% of body weight (0.98 ± 4.5 kg), normalizing by 3 months. Body mass index percentile normalized at 1 year, but height percentile was increased at 2 weeks (2.42 ± 1.72 cm, p < 0.001) and through 2 years.

Conclusion

Despite initial height increase due to deformity correction, acute postoperative weight and body mass index percentile decreases postoperatively normalize by 1-year body mass index percentile. Physicians may benefit from utilizing this information when discussing the postoperative course of posterior spinal fusion with idiopathic scoliosis.

Level of evidence

4, Retrospective Case Series.

Biomechanical Comparison of Different Numbers and Configurations of Cross-Links in Long-Segment Spinal Fixation-An Experimental Study in a Porcine Model

STUDY DESIGN

Biomechanical study.

OBJECTIVE

Cross-links are a type of common clinical spinal instrumentation. However, the effects of the position and number of cross-links have never been investigated in long-segment spinal fixation, and the variables have not been optimized. We conducted an in vitro biomechanical study by using a porcine long-segment spinal model with 5 different crosslink configurations to determine the optimal construct for clinical practice.

METHODS

Five modalities with paired segmental screws from T15-L5 were tested in 20 porcine spines. The spines without cross-links composed the control group, Group A; those with a single cross-link from L2-3 composed Group B; those with 2 cross-links from L1-2 and L3-4 composed Group C; those with 2 cross-links from T15-L1 and L4-5 composed Group D; and those with 3 cross-links from T15-L1, L2-3 and L4-5 composed Group E. Spinal stiffnesses in flexion, extension, lateral bending, and axial rotation were compared among 5 different cross-link configurations in 5-level porcine spinal units.

RESULTS

Flexional, extensional and lateral bending stiffnesses did not significantly change with an increasing number of cross-links or positions in the construct. Axial stiffness was significantly increased with 2 cross-links compared to one (P < 0.05) and with placement more distant from the center of the long spinal fixation construct (P < 0.05).

CONCLUSIONS

Two cross-links individually placed proximal and distal from the center of a construct is an optimal and efficient configuration to achieve biomechanical stability in non-rigid lumbar spines undergoing long-level fixation.

Height Gain Prediction in Adolescent Idiopathic Scoliosis Based on Preoperative Parameters

BACKGROUND

The purpose of the study was to identify preoperative parameters which are associated with height gain after corrective surgery for adolescent idiopathic scoliosis (AIS) and their use to preoperatively quantify the potential for height gain after AIS correction.

METHODS

Our study included 87 consecutive patients with AIS who underwent posterior fusion. Patients' height was measured the day before surgery and before their discharge. Demographic and radiologic variables were analyzed for predictability of height gain.

RESULTS

The mean height gain was 3.85 cm. We have found a statistically significant correlation between height gain and the following measures: preoperative thoracic curve, preoperative thoracolumbar curve, preoperative thoracic kyphosis, flexibility of the main thoracic and thoracolumbar curves, and number of fused levels (all P<0.05). Patients with Lenke type 1 and 2 had statistically less height gain compared with patients with Lenke type 3, 4, 6.

CONCLUSION

Most of the scoliosis patients with Lenke type 1 and 2 will gain up to 3 cm after surgery while most of the patients with Lenke type 3, 4, 6 will gain more than 3 cm. Most patients with Lenke type 3, 4, 6 with a major curve of less than 60 degrees will gain up to 4 cm, while most of those with a major curve of more than 60 degrees will gain more than 4 cm. Patient with a positive thoracic sagittal modifier tend to have more height gain after surgery.

Determinants of Postoperative Spinal Height Change among Adult Spinal Deformity Patients with Long Construct Circumferential Fusion

Study Design

Retrospective clinical study.

Purpose

To describe postoperative height changes and identify the predictive factors of spinal height (SH) changes among patients with adult spinal deformity (ASD) who underwent circumferential lumbar fusion with instrumentation.

Overview of Literature

Postoperative height changes remain an important issue after spinal fusion surgery that affects the overall satisfaction with surgery. Previous studies of postoperative height change have focused exclusively on young patients with adolescent idiopathic scoliosis (AIS).

Methods

We retrospectively reviewed the clinical and imaging data of ASD patients who underwent lumbar corrective circumferential fusion of ≥3 levels (n=106). SH was defined as the vertical distance between C2 and S1 on a standing lateral image. As potential predictors of postoperative height change, the number of lateral lumbar interbody fusion (LLIF) levels, change in spino-pelvic parameters, total number of levels fused, and pedicle subtraction osteotomies (PSO) were documented. Univariate and multivariate linear regression analyses were performed to identify the predictors of postoperative height change.

Results

The mean SH change was -2.39±50.8 mm (range, -160 to 172 mm). The univariate analyses showed that the number of LLIF levels (coefficient=10.9, p=0.03), the absolute coronal vertical axis change (coefficient=0.6, p=0.01), and the absolute Cobb angle change (coefficient=-0.9, p=0.03) were significant predictors for height change. Patients with PSOs (n=14) tended to have a shorter height postoperatively (coefficient=-26.1); however, this difference was not significant (p=0.07). Multivariate analyses conducted with variables of p<0.20 showed that pelvic tilt (PT) change is an independent contributor to SH change (coefficient=-0.99, p=0.04, R2=0.11).

Conclusions

Utilizing a modified definition of SH used in previous AIS studies, we demonstrated that patients with ASD lose SH postoperatively and that PT change was an independent contributor of SH change.

The publication trends and hot spots of scoliosis research from 2009 to 2018: a 10-year bibliometric analysis

Background

This study aims to quantitatively and qualitatively investigate the trends in scoliosis research and evaluate research hotspots using bibliometric analysis.

Methods

All relevant publications on scoliosis from the period from 2009 to 2018 were extracted from the Web of Science and PubMed databases. Publication trends were analyzed using an Online analysis platform of literature metrology, Bibliographic Item Co-occurrence Matrix Builder (BICOMB), and CiteSpace software. Hotspots were analyzed and visualized using the gCLUTO software package.

Results

A total of 7,445 scoliosis research publications dated between 2009 and 2018 were found. The spine was the most popular journal in this field during this period. The United States maintained a top position in global scoliosis research throughout the 10 years and has had a pivotal influence, followed by China and Canada. Among all institutions, the University of California, San Francisco, was a leader in research collaboration. At the same time, Professors Yong Qiu and Lawrence G. Lenke made great achievements in scoliosis research. We analyzed the major Medical Subject Headings (MeSH) terms/MeSH subheadings and identified eight hotspots in scoliosis research.

Conclusions

We summarized the publication information of scoliosis-related literature in the 10 years from 2009 to 2018, including country and institution of origin, authors, and publication journal. We analyzed former research hotspots in the field of scoliosis and predicted future areas of interest. The development of various new orthopedic plants, artificial intelligence diagnosis, and genetic research will be future hotspots in scoliosis research.

Predicted final spinal height in patients with adolescent idiopathic scoliosis can be achieved by surgery regardless of maturity status

AIMS

The aim of this study was to investigate the impact of maturity status at the time of surgery on final spinal height in patients with an adolescent idiopathic scoliosis (AIS) using the spine-pelvic index (SPI). The SPI is a self-control ratio that is independent of age and maturity status.

PATIENTS AND METHODS

The study recruited 152 female patients with a Lenke 1 AIS. The additional inclusion criteria were a thoracic Cobb angle between 45° and 70°, Risser 0 to 1 or 3 to 4 at the time of surgery, and follow-up until 18 years of age or Risser stage 5. The patients were stratified into four groups: Risser 0 to 1 and selective fusion surgery (Group 1), Risser 0 to 1 and non-selective fusion (Group 2), Risser 3 to 4 and selective fusion surgery (Group 3), and Risser 3 to 4 and non-selective fusion (Group 4). The height of spine at follow-up (HOS_f) and height of pelvis at follow-up (HOP_f) were measured and the predicted HOS (pHOS) was calculated as 2.22 (SPI) × HOP_f. One-way analysis of variance (ANOVA) was performed for statistical analysis.

RESULTS

Of the 152 patients, there were 32 patients in Group 1, 27 patients in Group 2, 48 patients in Group 3, and 45 patients in Group 4. Significantly greater HOS_f was observed in Group 3 compared with Group 1 (p = 0.03) and in Group 4 compared with Group 2 (p = 0.02), with similar HOP_f (p = 0.75 and p = 0.83, respectively), suggesting that patients who undergo surgery at Risser grade of 0 to 1 have a shorter spinal height at follow-up than those who have surgery at Risser 4 to 5. HOS_f was similar to pHOS in both Group 1 and Group 2 (p = 0.62 and p = 0.45, respectively), indicating that undergoing surgery at Risser 0 to 1 does not necessarily affect final spinal height.

CONCLUSION

This study shows that fusion surgery at Risser 0 may result in growth restriction unlike fusion surgery at Risser 3 to 4. Despite such growth restriction, AIS patients could reach their predicted or 'normal' spinal height after surgery regardless of baseline maturity status due to the longer baseline spinal length in AIS patients and the remaining growth potential at the non-fusion levels. Cite this article: Bone Joint J 2018;100-B:1372-6.