Low-Density Pedicle Screw Constructs for Adolescent Idiopathic Scoliosis: Evaluation of Effectiveness and Cost

Assessment of the Efficacy of Low-Density Pedicle Screw Construction Correction of Adolescent Idiopathic Scoliosis: A Prospective Single-Center Study

Background Adolescent idiopathic scoliosis (AIS) poses physical and psychological challenges for affected individuals, necessitating effective and less invasive treatment approaches. This study aimed to evaluate the efficacy of low-density posterior pedicle screw fixation in AIS correction, exploring its impact on deformity parameters, patient quality of life, and potential complications. Methodology A prospective study involving 20 AIS patients, employing low-density pedicle screw fixation, was conducted. Clinical, radiological, and Scoliosis Research Society (SRS-22) outcomes were assessed. Data analysis was conducted using SPSS version 26 software (IBM Corp., Armonk, NY, USA). Results Significant reductions in major and minor curve Cobb angles were observed (mean major curve reduction: 79.14%, p < 0.001; mean minor curve reduction: 68.91%, p < 0.001), indicating substantial deformity correction. As measured by the SRS-22 questionnaire, quality of life showed noteworthy improvements (mean pain score increase: 0.54, p < 0.05; mean self-image score increase: 1.22, p < 0.01), reflecting enhanced patient satisfaction and well-being. Complications were documented in four (20%) cases, including infection, adding-on phenomenon, proximal junctional kyphosis, and thoracic hypokyphosis. Conclusions Our study highlights the efficacy of low-density pedicle screw constructs in AIS correction. Significant deformity reductions and improved quality of life underscore the success of the approach. However, long-term studies with larger cohorts are crucial for confirming durability.

The effect of the caudal insertion angle of pedicle screws on postoperative thoracic kyphosis in adolescent idiopathic scoliosis: a pilot study

The study was a prospective analysis of collected data to compare the effect of the insertion angle (parallel or oblique relative to the upper-end plates) of thoracic pedicle screws on postoperative thoracic kyphosis in patients with idiopathic thoracic scoliosis. This study was conducted on idiopathic adolescent scoliosis (AIS) patients. Two groups of patients were defined according to the insertion angle of thoracic pedicle screws in relation to the upper-end plate of the corresponding vertebra, the insertion angles being either oblique or parallel. Seven consecutive AIS patients were compared in each group. Pre- and postoperative standing X-rays were obtained. Cobb's angles, sagittal parameters such as thoracic kyphosis (TK) (T1-T12) and lumbar lordosis (LL) (L1-S1) were all measured. The average of the main curve or compensatory curve corrections showed no significant differences between the two groups. From a sagittal profile perspective, the mean TK in the oblique screw group was 39.3 ± 11.5 preoperatively, which was reduced to 30.9 ± 6.41 after surgery. The mean TK in the parallel group was 36.4 ± 14 preoperatively and 42.1 ± 13.9 postoperatively. There was a significant reduction in TK in the oblique screws group compared with the second group ( P  = 0.038). The insertion angle of pedicle screws had no significant effect on Cobb's angle and lumbar lordosis changes. However, oblique insertion of thoracic screws decreased thoracic kyphosis postoperatively, which could be considered a negative point. As such, the insertion of thoracic screws in a caudal direction should not be routinely used because of its lordogenic effect.

Higher pedicle screw density does not improve curve correction in Lenke 2 adolescent idiopathic scoliosis

Purpose

Higher pedicle screw density posterior spinal fusion (PSF) constructs have not been shown to result in improved curve correction in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS) but do increase cost. The purpose of this study questioned whether higher screw density constructs improved curve correction and maintenance of correction in Lenke 2 AIS. Secondary goals were to identify predictive factors for correction and postoperative magnitude of curves in Lenke 2 AIS.

Methods

We identified patients 11 to 17 years old who underwent primary PSF for Lenke 2 AIS between 2007 and 2017 who had minimum follow-up of 2 years. Demographic and radiographic data were collected to perform regression and elimination analysis.

Results

Thirty patients (21 females, 9 males) were analyzed. Average age and SD at time of surgery was 14.0 ± 1.8 years (range, 11–17 years), and median follow-up was 2.8 years (IQR 2.1–4.0 years). Implant density did not predict final postoperative curve magnitude. Predictors of final postoperative curve magnitude were sex and preoperative curve magnitude. Predictors of percentage of correction of major curve were sex and age at the time of surgery. Predictors of final postoperative thoracic kyphosis were sex and percent flexibility preop. Females had lower final postoperative major curve magnitude, a higher percent curve correction, and lower postoperative thoracic kyphosis.

Conclusions

Increased implant density is not predictive of postoperative curve magnitude in Lenke 2 AIS. Predictors of postoperative curve magnitude are sex and preoperative curve magnitude.

Level of evidence

Level III, retrospective observational

Trends in Medical Costs for Adolescent Idiopathic Scoliosis Surgery in Japan

STUDY DESIGN

A retrospective review of clinical data and costs was performed for surgeries for adolescent idiopathic scoliosis (AIS) conducted from 2008 to 2017.

OBJECTIVE

Cost containment and healthcare value have become focal points in Japanese health care policy. The purpose of the study was to investigate trends over time in medical costs for surgery for AIS.

METHODS

A total of 83 patients underwent surgery for AIS from 2008 to 2017 at our hospital. Clinical data and length of stay were collected, and medical costs for surgery, local bone grafting, fees per day, and surgical instruments were evaluated.

RESULTS

There were slight year-by-year decreases in fees per day and decreases in costs of surgical instruments. The average length of stay was 16.4 days and gradually decreased over time. In contrast, scoliosis surgery costs increased about 1.6 times in 10 years from $9515 to $15 130.

CONCLUSION

The trends for decreases in fees per day and prices for surgical instruments reflect recent government medical cost control policies. The cost for scoliosis surgery is also defined by the government, and the increase over 10 years may reflect the perspective of valuing effective and advanced surgeries. This study of cost trends of operative spinal intervention provides an assessment of surgical benefit and is likely to influence health care costs.

Correction of thoracic adolescent idiopathic scoliosis via a direct convex rod manoeuvre

The various techniques available for scoliosis surgery via the posterior approach involve positioning implants on either side of the curve and reducing the deformity by manoeuvres on the concave rod or simultaneously on both rods. Correction solely via a direct convex rod manoeuvre would eliminate the need for implants on the concave side. This technique was used to treat thoracic adolescent idiopathic scoliosis in 23 patients with a mean age of 14 years and 9 months. Low-dose biplanar EOS radiographs were obtained before surgery, on post-operative day 7, and at last follow-up (at least 2 years after surgery) to allow comparisons of Cobb's angle (72°, 33°, and 35°, respectively), thoracic kyphosis (21°, 29°, and 26°), lumbar lordosis (58°, 50°, and 55°), and apical vertebra rotation (-26°,-12°, and-11°). Although scoliosis requires corrections in all three dimensions, this technique seems to produce satisfactory outcomes while obviating the need for implants on the concave side, thereby decreasing the risk of iatrogenic adverse events. LEVEL OF EVIDENCE: IV.

Anterior and Posterior Fusion for Large, Rigid Idiopathic Scoliosis: Does Implant Density Matter?

BACKGROUND

Despite advancements in surgical techniques, controversy remains regarding the optimal implant density for the correction of idiopathic scoliosis. Recent evidence has suggested that equivalent radiographic and clinical outcomes can be achieved with lower implant densities for those with moderate curves and good flexibility. Among the experts, the consensus has continued that higher implant densities should be used for larger, stiffer curves. The purpose of the present study was to compare the radiographic results between high-implant density (HID) and low-implant density (LID) constructs in patients with large (>65°), rigid (<50% flexibility) curves who had undergone anterior release and posterior spinal fusion.

METHODS

We reviewed the idiopathic scoliosis cases performed at a single institution from 2006 to 2014. Only those meeting the inclusion criteria were selected. The patients were divided into HID and LID groups. The postoperative radiographs were compared for coronal correction, thoracic kyphosis, pelvic tilt, lumbar lordosis, and sagittal vertical axis.

RESULTS

A statistically significant improvement in coronal correction was detected in the HID group at all follow-up points (final follow-up: HID, 81.1% vs. LID, 70.4%; P = 0.01). When preoperative thoracic kyphosis was considered, no differences were found between the 2 groups. No differences were found in the other sagittal parameters.

CONCLUSION

In patients with large, rigid idiopathic scoliosis undergoing anterior release and posterior spinal fusion, a small, but statistically, significant improvement in the coronal Cobb angle was seen. It remains to be determined whether this small difference in radiographic correction will have any influence on the clinical outcome.

Reciprocal Changes in Sagittal Alignment in Adolescent Idiopathic Scoliosis Patients Following Strategic Pedicle Screw Fixation

Study Design

Retrospective observational study.

Purpose

To analyze the effect of low-density (LD) strategic pedicle screw fixation on the correction of coronal and sagittal parameters in adolescent idiopathic scoliosis (AIS) patients.

Overview of Literature

LD screw fixation achieves favorable coronal correction, but its effect on sagittal parameters is not well established. AIS is often associated with decreased thoracic kyphosis (TK), and the use of multi-level pedicle screws may result in further flattening of the sagittal profile.

Methods

A retrospective analysis was performed on 92 patients with AIS to compare coronal and sagittal parameters preoperatively and at 2-year follow-up. All patients underwent posterior correction via LD strategic pedicle screw fixation. Radiographs were analyzed for primary Cobb angle (PCA), coronal imbalance, cervical sagittal angle (CSA), TK, lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope (SS), C7 plumb line, spino-sacral angle, curve flexibility, and screw density.

Results

PCA changed significantly from 57.6°±13.9° to 19°±8.4° (p <0.0001) with 67% correction, where the mean curve flexibility was 41% and screw density was 68%. Regional sagittal parameters did not change significantly, including CSA (from 10.76° to 10.56°, p =0.893), TK (from 24.4° to 22.8°, p =0.145), and LL (from 50.3° to 51.1°, p =0.415). However, subgroup analysis of the hypokyphosis group (<10°) and the hyperkyphosis group (>40°) showed significant correction of TK (p <0.0001 in both). Sacro-pelvic parameters showed a significant decrease of PT and increase of SS, suggesting a reduction in pelvic retroversion SS (from 37° to 40°, p =0.0001) and PT (from 15° to 14°, p =0.025).

Conclusions

LD strategic pedicle screw fixation provides favorable coronal correction and improves overall sagittal sacro-pelvic parameters. This technique does not cause significant flattening of TK and results in a favorable restoration of TK in patients with hypokyphosis or hyperkyphosis.