Clinical Outcomes of Corrective Fusion Surgery From the Thoracic Spine to the Pelvis for Adult Spinal Deformity at 1, 2, and 5 years Postoperatively

Long-term Outcomes After Adult Spinal Deformity Surgery Using Lateral Interbody Fusion: Short Versus Long Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate long-term outcomes after short or long fusion for adult spinal deformity using lateral interbody fusion.

SUMMARY OF BACKGROUND DATA

Lateral interbody fusion is commonly used in adult spinal deformity surgery. Favorable short-term outcomes have been reported, but not long-term outcomes. Lateral interbody fusion with strong ability to correct deformity may allow the selection of short fusion techniques.

MATERIALS AND METHODS

We retrospectively reviewed adults who underwent this surgery with a minimum of 5 years of follow-up. Short fusion with the uppermost instrumented vertebra in the lumbar spine was performed in patients without degenerative changes at the thoracolumbar junction (S-group); others underwent long fusion with the uppermost instrumented vertebra in the thoracic spine (L-group). We assessed radiographic and clinical outcomes.

RESULTS

Short fusion was performed in 29 of 54 patients. One patient per group required revision surgery. Of the remainder, with similar preoperative characteristics and deformity correction between groups, correction loss (pelvic incidence-lumbar lordosis, P =0.003; pelvic tilt, P =0.005; sagittal vertical axis, P ˂0.001) occurred within 2 years postoperatively in the S-group, and sagittal vertical axis continued to increase until the 5-year follow-up ( P =0.021). Although there was a significant change in Oswestry disability index in the S-group ( P =0.031) and self-image of Scoliosis Research Society 22r score in both groups ( P =0.045 and 0.02) from 2- to 5-year follow-up, minimum clinically important differences were not reached. At 5-year follow-up, there was a significant difference in Oswestry Disability Index ( P =0.013) and Scoliosis Research Society 22r scores (function: P =0.028; pain: P =0.003; subtotal: P =0.006) between the groups, but satisfaction scores were comparable and Oswestry Disability Index score (29.8%) in the S-group indicated moderate disability.

CONCLUSIONS

Health-related quality of life was maintained between 2- and 5-year follow-up in both groups. Short fusion may be an option for patients without degenerative changes at the thoracolumbar junction.

LEVEL OF EVIDENCE

III.

Do different pathologies of adult spinal deformity (idiopathic lumbar scoliosis against de novo lumbar scoliosis) affect preoperative and postoperative selfimage?

STUDY DESIGN

Retrospective single-center study.

PURPOSE

This study aimed to examine the factors associated with the self-image domain of the Scoliosis Research Society-22 revised (SRS-22r) in patients who underwent corrective surgery for adult idiopathic scoliosis (AdIS).

OVERVIEW OF LITERATURE

Adult spinal deformity (ASD) can be classified into AdIS and de novo scoliosis. However, no studies have investigated the effect of different ASD pathologies on self-image.

METHODS

This study enrolled 60 patients who underwent corrective surgery and were followed up for >2 years postoperatively. AdIS was defined as adolescent idiopathic scoliosis in patients who had no history of corrective surgery, had a primary thoracolumbar/lumbar (TL/L) curve, and were ≥30 years old at the time of surgery.

RESULTS

The AdIS (n=23; mean age, 53.1 years) and de novo (n=37; mean age, 70.0 years) groups were significantly different in terms of the main thoracic and TL/L curves, sagittal vertical axis, thoracic kyphosis, and thoracolumbar kyphosis preoperatively. The scores in the self-image domain of the SRS-22r (before surgery/2 years after surgery [PO2Y]) were 2.2/4.4 and 2.3/3.7 in the AdIS and de novo groups, respectively, and PO2Y was significantly different between the two groups (p<0.001). Multivariate regression analysis revealed that AdIS was an independent factor associated with self-image at PO2Y (p=0.039).

CONCLUSIONS

AdIS, a spinal deformity pathology, was identified as a significant factor associated with the self-image domain of SRS-22r in patients who underwent corrective surgery. AdIS is not solely classified based on pathology but also differs in terms of the clinical aspect of self-image improvement following corrective surgery.

Cost-Effectiveness of Corrective Fusion Surgeries for Adult Spinal Deformities: Does Unexpected Revision Surgery Affect Cost-Effectiveness?

Introduction

Previous research has demonstrated that mid- to long-term health-related quality of life following corrective fusion surgery for adult spinal deformity (ASD) can be improved by appropriate revision surgery. In this study, we aim to compare the cost-effectiveness of corrective fusion surgery for ASD with and without unexpected revision surgery 5 years postoperatively.

Methods

In total, 79 patients with ASD (mean age, 68.7 years) who underwent corrective fusion surgery between 2013 and 2015 were included in this study. Cost-effectiveness was evaluated based on the cost of obtaining 1 quality-adjusted life year (QALY). Patients were divided into two groups according to the presence or absence of unexpected revision surgery following corrective fusion and were subjected for comparison.

Results

As per our study findings, 26 (33%) of the 79 ASD patients underwent unexpected revision surgery during the first 5 years following surgery. Although there was no significant difference in terms of inpatient medical costs at the time of initial surgery for 5 years after surgery between the two groups (no-revision group, revision group; inpatient medical costs at the time of initial surgery: USD 69,854 vs. USD 72,685, P=0.344), the total medical expenses up to 5 years after surgery were found to be higher in the revision group (USD 72,704 vs. USD 104,287, P<0.001). The medical expenses required to improve 1 QALY 5 years after surgery were USD 178,476 in the no-revision group, whereas it was USD 222,081 in the revision group.

Conclusions

Although the total medical expenses were higher in the revision group, no significant difference was observed in the cumulative QALY improvement between the revision and no-revision groups. Moreover, the medical expenses required to improve 1 QALY were higher in the revision group, with a difference of approximately 20%.

Minimal Clinically Important Differences in Gait and Balance Ability in Patients Who Underwent Corrective Long Spinal Fusion for Adult Spinal Deformity

STUDY DESIGN

Retrospective observational study.

BACKGROUND

The risk of a femoral neck fracture due to a fall after adult spinal deformity surgery has been reported. One of the most significant factors among walking and balance tests in post-operative ASD patients was the timed up-and-go test (TUG). This study aims to calculate the minimal clinically important difference (MCID) in balance tests after ASD surgery.

METHODS

Forty-eight patients, 4 males and 44 females, were included by exclusion criteria in 66 consecutive patients who underwent corrective surgery as a treatment for ASD at our institution from June 2017 to February 2022. The inclusion criteria for this study were age ≥50 years; and no history of high-energy trauma. The exclusion criteria were dementia, severe deformity of the lower extremities, severe knee or hip osteoarthritis, history of central nervous system disorders, cancer, and motor severe paralysis leading to gait disorders. The surgeries were performed in two stages, first, the oblique lumber interbody fusion (OLIF) L1 to L5 (or S1), and second, the posterior corrective fusion basically from T10 to pelvis. For outcome assessment, 10 m walk velocity, TUG, ODI, and spinopelvic parameters were used.

RESULTS

Ten meter walk velocity of pre-operation and post-operation were 1.0 ± 0.3 m/s and 1.2 ± 0.2 m/s, respectively (p < 0.01). The TUG of pre-operation and post-operation were 12.1 ± 3.7 s and 9.7 ± 2.2 s, respectively (p < 0.01). The ODI improved from 38.6 ± 12.8% to 24.2 ± 15.9% after surgery (p < 0.01). All post-operative parameters except PI obtained statistically significant improvement after surgery.

CONCLUSIONS

This is the first report of MCID of the 10 m walk velocity and TUG after ASD surgery. Ten meter walk velocity and the TUG improved after surgery; their improvement values were correlated with the ODI. MCID using the anchor-based approach for 10 m walk velocity and the TUG were 0.10 m/s and 2.0 s, respectively. These MCID values may be useful for rehabilitation after ASD surgery.

Cranially Directed Upper Instrumented Vertebrae Screw Angles Are Associated With Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To evaluate the impact of the upper instrumented vertebral (UIV) screw angle in adult spinal deformity (ASD) surgery on: (1) proximal junctional kyphosis/failure (PJK/F), (2) mechanical complications and radiographic measurements, and (3) patient-reported outcome measures (PROMs).

SUMMARY OF BACKGROUND DATA

The effect of UIV screw angle in ASD surgery on patient outcomes remains understudied.

MATERIALS AND METHODS

A single-institution, retrospective study was undertaken from 2011 to 2017. UIV screw angle was trichotomized into positive: cranially directed screws relative to the superior endplate (2°≤θ), neutral: parallel to the superior endplate (-2°<θ<2°), and negative: caudally directed screws relative to the superior endplate (-2°≥θ). The primary outcome was PJK/F. Secondary outcomes included remaining mechanical complications, reoperation, and PROMs: Oswestry Disability Index, Numeric Rating Scale (NRS) back/leg, and EuroQol. Regression controlled for age, body mass index, postoperative sagittal vertical axis (SVA), and pelvic incidence lumbar-lordosis mismatch.

RESULTS

Among 145 patients undergoing ASD surgery, UIV screw angles were 35 (24.1%) cranially directed, 24 (16.6%) neutral, and 86 (59.3%) caudally directed. PJK occurred in 47(32.4%) patients. Positive screws were independently associated with increased PJK [odds ratio (OR)=4.88; 95% CI, 1.85-13.5, P =0.002] and PJF (OR=3.06; 95% CI, 1.32-12.30, P =0.015). Among 108 (74.5%) patients with lower thoracic UIV, PJK occurred in 38 (35.1%). Cranially directed screws were independently associated with an increased odds of PJK (OR=5.56; 95% CI, 1.86-17.90, P =0.003) with a threshold of 0.2° (area under the curve =0.65; 95% CI, 0.54-0.76, P <0.001), above which the risk of PJK significantly increased. No association was found between positive screw angle and PJF (OR=3.13; 95% CI, 0.91-11.40, P =0.073). Because of the low number of patients with an upper thoracic UIV (N=37, 25.5%), no meaningful conclusions could be drawn from this subgroup. There was no association between UIV screw angle and remaining mechanical complications, reoperations, postoperative SVA and T1-pelvic angle, or PROMs.

CONCLUSIONS

Cranially directed UIV screw angles increased the odds of PJK in patients with lower thoracic UIV. Meticulous attention should be paid to the lower thoracic UIV screw angle to mitigate the risk of PJK in ASD.