Predictors of cost for posterior spinal fusion in adolescent idiopathic scoliosis

Optimising operating theatre (OT) efficiency while maintaining the standardised patient care in adolescent idiopathic scoliosis (AIS) surgery with the dedicated spine team approach: a specialised spine unit experience

PURPOSE

To report the efficiency of OT utilisation and perioperative outcomes with a dedicated spine team approach in AIS patients who underwent posterior spinal fusion (PSF) surgeries in a consecutive case operation list.

METHODS

Three AIS patients operated in a day (8:00 AM-8:00 PM) by a dedicated spine team were recruited between 2021 and 2022. The dedicated team comprised of three senior spine consultants who operated using a dual attending surgeon strategy, an anaesthetic consultant, dedicated surgical scrub nurses, anaesthesiology nurses, radiographers, and neuromonitoring technicians. Patients were categorised according to the sequence of operation list of the day (Case 1, Case 2, and Case 3). OT efficiency was represented by OT time in five stages (preoperative time, operative time, postoperative time, total OT time, and turnover time). OT time and perioperative outcomes were compared.

RESULTS

102 cases were analysed. On average, Case 1 began at 8:38 AM whereas Case 3 ended by 5:54 PM. OT efficiency was consistent throughout the day of operation with comparable OT time in all five stages between groups (p > 0.05). The mean turnover time was 15.1 ± 13.5 min and the mean operative time was 123.0 ± 28.1 min. Intraoperative arterial blood gas (ABG) parameters were maintained in an optimal range. The complication rate was 2.0% (N = 2/102).

CONCLUSION

Consistent OT efficiency was demonstrated with a dedicated spine team approach. Despite performing three AIS cases in a consecutive case operation list, patients' safety was not compromised as perioperative outcomes between groups were comparable.

The Effect of Implant Density on Adolescent Idiopathic Scoliosis Fusion: Results of the Minimize Implants Maximize Outcomes Randomized Clinical Trial

BACKGROUND

Severe adolescent idiopathic scoliosis (AIS) can be treated with instrumented fusion, but the number of anchors needed for optimal correction is controversial.

METHODS

We conducted a multicenter, randomized study that included patients undergoing spinal fusion for single thoracic curves between 45° and 65°, the most common form of operatively treated AIS. Of the 211 patients randomized, 108 were assigned to a high-density screw pattern and 103, to a low-density screw pattern. Surgeons were instructed to use ≥1.8 implants per spinal level fused for patients in the high-implant-density group or ≤1.4 implants per spinal level fused for patients in the low-implant-density group. The primary outcome measure was the percent correction of the coronal curve at the 2-year follow-up. The power analysis for this trial required 174 patients to show equivalence, defined as a 95% confidence interval (CI) within a ±10% correction margin with a probability of 90%.

RESULTS

In the intention-to-treat analysis, the mean percent correction of the coronal curve was equivalent between the high-density and low-density groups at the 2-year follow-up (67.6% versus 65.7%; difference, -1.9% [95% CI: -6.1%, 2.2%]). In the per-protocol cohorts, the mean percent correction of the coronal curve was also equivalent between the 2 groups at the 2-year follow-up (65.0% versus 66.1%; difference, 1.1% [95% CI: -3.0%, 5.2%]). A total of 6 patients in the low-density group and 5 patients in the high-density group required reoperation (p = 1.0).

CONCLUSIONS

In the setting of spinal fusion for primary thoracic AIS curves between 45° and 65°, the percent coronal curve correction obtained with use of a low-implant-density construct and that obtained with use of a high-implant-density construct were equivalent.

LEVEL OF EVIDENCE

Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Impact of preoperative intervention for smoking cessation on postoperative length of stay and cost for spine surgery patients: Propensity score matching analysis

BACKGROUND

Preoperative intervention for smoking cessation reduces the prevalence of postoperative complications in spine surgery. To date, however, the impact of these interventions on the length of stay (LOS) and cost for patients is unclear.

PATIENTS/METHODS

This retrospective cohort study analyzed data from 317 patients who were current smokers and underwent spine surgery between January 2014 and December 2019 at a single facility in Tokyo, Japan. Most patients (262) received preoperative intervention for smoking cessation within 60 days before spine surgery; the remaining 55 patients did not receive the intervention. The postoperative LOS was compared using propensity score matching. Patients were matched for age, gender, body mass index, surgical plan (cervical surgery, anterior approach surgery, minimally invasive surgery), preoperative comorbidities (diabetes mellitus, hypertension, ischemic cardiac disease, chronic lung disease), and recent history of steroid therapy, which yielded 48 pairs of patients.

RESULTS

The length of postoperative hospital stay was significantly shorter in the intervention group (-10.60 days, [95% CI, -15.79 to -5.42]). The cost for service was significantly lower in the intervention group (coefficient, Japanese yen [JPY] -1,515,529; [95% CI, -2,130,631 to -900,426]; 110 JPY equivalent to 1 United States dollar).

CONCLUSIONS

Preoperative interventions for smoking cessation may decrease postoperative hospital stay and hospitalization costs.

Correlation between Scoliosis Flexibility Degree on Preoperative Imaging with Postoperative Curve Correction and Mechanical Complications

(1) Background: In the preoperative planning stage of scoliosis surgery, it is routine to use radiographs obtained with and without traction to observe the curve flexibility in order to estimate curve correction, but its association with mechanical complications is not completely understood. (2) Methods: Retrospective cohort study of all patients undergoing infantile, congenital, neuromuscular or idiopathic adolescent scoliosis correction surgery at a single institution between 2015 and 2019, with a minimum follow-up of 24 months. Associations between qualitative variables were tested with the chi-square test. The association between qualitative and quantitative variables were tested with the Mann–Whitney test, and correlations between quantitative variables was tested with Spearman’s correlation. (3) Results: A total of 330 patients, 88 males and 242 females, with a mean age of 16.98 years at surgery, were included. The mean value of preoperative main curves, its flexibility and postoperative value were 54.44 degrees, 21.73 degrees and 18.08 degrees, respectively. (4) Conclusions: Preoperative spinal X-ray examination with traction or bending films is a reasonable option for assessing scoliotic curve flexibility, and patients with neuromuscular scoliosis who are not ambulatory can be informed of the increased risks of late mechanical complications.

Severe Lenke 1 and 2 adolescent idiopathic scoliosis had poorer perioperative outcome, higher complication rate, longer fusion and higher operative cost compared to non-severe scoliosis

PURPOSE

To compare the perioperative outcome and operative cost of posterior spinal fusion (PSF) surgery between severe and non-severe Lenke 1 and 2 adolescent idiopathic scoliosis (AIS) patients.

METHODS

A total of 509 AIS patients who underwent single-staged PSF between 2013 and 2020 were reviewed. Fifty-four severe scoliosis patients (Cobb angle ≥ 90°) were categorized into Gp1, and 455 non-severe scoliosis (Cobb angle < 90°) patients into Gp2. Propensity score matching (PSM) analysis using one-to-one nearest neighbor matching and match tolerance of 0.001 were performed. Outcome measures were operative time, intraoperative blood loss (IBL), allogeneic transfusion rate, perioperative complication, length of stay, fusion level, number of screws used, postoperative Cobb angle, correction rate (CR), side bending correction index (SBCI) and operative cost.

RESULTS

From the PSM analysis, 35 patients from each group were matched. The operative time was 155.9 ± 41.4 and 130.0 ± 30.3 min for Gp1 and Gp2, respectively (p = 0.004). The IBL was 1349.2 ± 1019.0 and 781.9 ± 325.1 mLs for Gp1 and Gp2, respectively (p = 0.003). Fusion level (12.5 ± 0.8 vs. 11.2 ± 1.3, p < 0.001) and number of screws used (16.4 ± 1.6 vs. 14.6 ± 1.4, p < 0.001) were higher in Gp1. Four perioperative complications were observed in Gp1 compared to none in Gp2 (p < 0.039). Gp1 had larger postoperative Cobb angle (p < 0.001), lower CR (p = 0.005) and higher SBCI (p < 0.001). The operative cost was higher in Gp1 (p < 0.001).

CONCLUSIONS

Severe Lenke 1 and 2 AIS patients had poorer perioperative outcome, higher complication rate, longer fusion and higher operative cost than non-severe AIS.

Local Bone Grafting Is Sufficient for Instrumented Adolescent Idiopathic Scoliosis Surgery: A Preliminary Study

BACKGROUND

Several options for grafting exist; iliac crest bone grafting, allografts, and bone substitutes. Local bone graft (LBG) offers high-quality bone graft and no commercial cost. The aim of this study was to assess the clinical and radiologic results of adolescent idiopathic scoliosis (AIS) surgery with posterior instrumentation and fusion (PIF) in patients using only LBG and to measure the quantities harvested.

METHODS

A total of 218 AIS patients who underwent pedicle screw PIF surgery using only LBG with a minimum 1-year follow-up were reviewed. Bone was harvested during surgery from the excised facet joints, spinous processes (not from the end instrumented vertebrae) and decortication of laminae and transverse processes in the operative field. The harvested bone graft weight of 127 patients was recorded prospectively and then computed to graft weight per kilogram body weight (GWPK) and graft weight per motion segment (GWPMS).

RESULTS

The median follow-up time was 24.7 months (12.1 to 133 mo) with 128 of the 218 patients having over 2 years follow-up. A total of 280 curves were fused. One hundred fifty-six of the patients had single curve instrumentation and 62 had double curve surgery. The median preoperative primary Cobb angle was 57.0 (31 to 100) degrees and postoperatively was 20.0 (0 to 66) degrees, indicating a median correction of 65.3% (17.5% to 100%). The median graft weight was 30 g (14 to 62 g), GWPK was 0.54 g/kg (0.24 to 1.29 g/kg) and GWPMS was 3.3 g/motion segments (2.3 to 10.0 g/kg). Twelve of 218 patients (5.5%) required subsequent surgery. Only 2 patients developed pseudarthrosis (0.91%), noting that modern segmental instrumentation warrants longer follow-up for increased confidence of complete fusion.

CONCLUSIONS

LBG achieved successful fusion in over 99% of patients undergoing PIF for AIS. The described terms GWPK and GWPMS can be insightful for future studies. LBG offers a safe and low-cost solution for bone grafting in AIS surgery.

LEVEL OF EVIDENCE

Level IV.

Cost-Utility Analysis of Anterior Vertebral Body Tethering versus Spinal Fusion in Idiopathic Scoliosis from a US Integrated Healthcare Delivery System Perspective

Purpose

Anterior vertebral body tethering (VBT) is a non-fusion, minimally invasive, growth-modulating procedure with some early positive clinical outcomes reported in pediatric patients with idiopathic scoliosis (IS). VBT offers potential health-related quality of life (HRQoL) benefits over spinal fusion in allowing patients to retain a greater range of motion after surgery. We conducted an early cost-utility analysis (CUA) to compare VBT with fusion as a first-choice surgical treatment for skeletally immature patients (age >10 years) with moderate to severe IS, who have failed nonoperative management, from a US integrated healthcare delivery system perspective.

Patients and Methods

The CUA uses a Markov state transition model, capturing a 15-year period following index surgery. Transition probabilities, including revision risk and subsequent fusion, were based on published surgical outcomes and an ongoing VBT observational study (NCT02897453). Patients were assigned utilities derived from published patient-reported outcomes (PROs; SRS-22r mapped to EQ-5D) following fusion and the above VBT study. Index and revision procedure costs were included. Probabilistic (PSA) and deterministic sensitivity analyses (DSA) were performed.

Results

VBT was associated with higher costs but also higher quality-adjusted life years (QALYs) than fusion (incremental costs: $45,546; QALYs gained: 0.54). The subsequent incremental cost-effectiveness ratio for VBT vs fusion was $84,391/QALY gained. Mean PSA results were similar to the base case, indicating that results were generally robust to uncertainty. The DSA indicated that results were most sensitive to variations in utility values.

Conclusion

This is the first CUA comparing VBT with fusion in pediatric patients with IS and suggests that VBT may be a cost-effective alternative to fusion in the US, given recommended willingness-to-pay thresholds ($100,000–$150,000). The results rely on HRQoL benefits for VBT compared with fusion. For improved model accuracy, further analyses with longer-term PROs for VBT, and comparative effectiveness studies, would be needed.