Postoperative Recovery After Adult Spinal Deformity Surgery: Comparative Analysis of Age in 149 Patients During 2-year Follow-up

Explainable Machine Learning Approach to Prediction of Prolonged Intesive Care Unit Stay in Adult Spinal Deformity Patients: Machine Learning Outperforms Logistic Regression

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Prolonged ICU stay is a driver of higher costs and inferior outcomes in Adult Spinal Deformity (ASD) patients. Machine learning (ML) models have recently been seen as a viable method of predicting pre-operative risk but are often 'black boxes' that do not fully explain the decision-making process. This study aims to demonstrate ML can achieve similar or greater predictive power as traditional statistical methods and follows traditional clinical decision-making processes.

METHODS

Five ML models (Decision Tree, Random Forest, Support Vector Classifier, GradBoost, and a CNN) were trained on data collected from a large urban academic center to predict whether prolonged ICU stay would be required post-operatively. 535 patients who underwent posterior fusion or combined fusion for treatment of ASD were included in each model with a 70-20-10 train-test-validation split. Further analysis was performed using Shapley Additive Explanation (SHAP) values to provide insight into each model's decision-making process.

RESULTS

The model's Area Under the Receiver Operating Curve (AUROC) ranged from 0.67 to 0.83. The Random Forest model achieved the highest score. The model considered length of surgery, complications, and estimated blood loss to be the greatest predictors of prolonged ICU stay based on SHAP values.

CONCLUSIONS

We developed a ML model that was able to predict whether prolonged ICU stay was required in ASD patients. Further SHAP analysis demonstrated our model aligned with traditional clinical thinking. Thus, ML models have strong potential to assist with risk stratification and more effective and cost-efficient care.

Complication Rates Following Adult Spinal Deformity Surgery: Evaluation of the Category of Complication and Chronology

OBJECTIVE

Provide benchmarks for the rates of complications by type and timing.

STUDY DESIGN

Prospective multicenter database.

BACKGROUND

Complication rates following adult spinal deformity (ASD) surgery have been previously reported. However, the interplay between timing and complication type warrants further analysis.

METHODS

The data for this study were sourced from a prospective, multicenter ASD database. The date and type of complication were collected and classified into three severity groups (minor, major, and major leading to reoperation). Only complications occurring before the two-year visit were retained for analysis.

RESULTS

Of the 1260 patients eligible for two-year follow-up, 997 (79.1%) achieved two-year follow-up. The overall complication rate was 67.4% (N=672). 247 patients (24.8%) experienced at least one complication on the day of surgery (including intraoperatively), 359 (36.0%) between postoperative day 1 and six weeks postoperatively, 271 (27.2%) between six weeks and one-year postoperatively, and finally 162 (16.3%) between one year and two years postoperatively. Using Kaplan-Meier survival analysis, the rate of remaining complication-free was estimated at different time points for different severities and types of complications. Stratification by type of complication demonstrated that most of the medical complications occurred within the first 60 days. Surgical complications presented over two distinct timeframes. Operative complications, incision-related complications, and infections occurred early (within 60 d), while implant-related and radiographic complications occurred at a constant rate over the two-year follow-up period. Neurological complications had the highest occurrence within the first 60 days but continued to increase up to the two-year visit.

CONCLUSION

Only one-third of ASD patients remained complication-free by two years, and 2 of 10 patients had a complication requiring a reoperation or revision. An estimation of the timing and type of complications associated with surgical treatment may prove useful for more meaningful patient counseling and aid in assessing the cost-effectiveness of treatment.

LEVEL OF EVIDENCE

3.

The Case for Operative Efficiency in Adult Spinal Deformity Surgery: Impact of Operative Time on Complications, Length of Stay, Alignment, Fusion Rates, and Patient-Reported Outcomes

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To analyze the impact of operative room (OR) time in adult spinal deformity (ASD) surgery on patient outcomes.

BACKGROUND

It is currently unknown if OR time in ASD patients matched for deformity severity and surgical invasiveness is associated with patient outcomes.

MATERIALS AND METHODS

ASD patients with baseline and two-year postoperative radiographic and patient-reported outcome measures (PROM) data, undergoing a posterior-only approach for long fusion (>L1-Ilium) were included. Patients were grouped into short OR time (<40th percentile: <359 min) and long OR time (>60th percentile: >421 min). Groups were matched by age, baseline deformity severity, and surgical invasiveness. Demographics, radiographic, PROM data, fusion rate, and complications were compared between groups at baseline and two years follow-up.

RESULTS

In total, 270 patients were included for analysis: the mean OR time was 286 minutes in the short OR group versus 510 minutes in the long OR group ( P <0.001). Age, gender, percent of revision cases, surgical invasiveness, pelvic incidence minus lumbar lordosis, sagittal vertical axis, and pelvic tilt were comparable between groups ( P >0.05). Short OR had a slightly lower body mass index than the short OR group ( P <0.001) and decompression was more prevalent in the long OR time ( P =0.042). Patients in the long group had greater hospital length of stay ( P =0.02); blood loss ( P <0.001); proportion requiring intensive care unit ( P =0.003); higher minor complication rate ( P =0.001); with no significant differences for major complications or revision procedures ( P >0.5). Both groups had comparable radiographic fusion rates ( P =0.152) and achieved improvement in sagittal alignment measures, Oswestry disability index, and Short Form-36 ( P <0.001).

CONCLUSION

Shorter OR time for ASD correction is associated with a lower minor complication rate, a lower estimated blood loss, fewer intensive care unit admissions, and a shorter hospital length of stay without sacrificing alignment correction or PROMs. Maximizing operative efficiency by minimizing OR time in ASD surgery has the potential to benefit patients, surgeons, and hospital systems.

Pre-operative bone quality deficits and risk of complications following spine fusion surgery among postmenopausal women

Poor bone quality is a risk factor for complications after spinal fusion surgery. This study investigated pre-operative bone quality in postmenopausal women undergoing spine fusion and found that those with small bones, thinner cortices and surgeries involving more vertebral levels were at highest risk for complications.

PURPOSE

Spinal fusion is one of the most common surgeries performed worldwide. While skeletal complications are common, underlying skeletal deficits are often missed by pre-operative DXA due to artifact from spinal pathology. This prospective cohort study investigated pre-operative bone quality using high resolution peripheral CT (HRpQCT) and its relation to post-operative outcomes in postmenopausal women, a population that may be at particular risk for skeletal complications. We hypothesized that women with low volumetric BMD (vBMD) and abnormal microarchitecture would have higher rates of post-operative complications.

METHODS

Pre-operative imaging included areal BMD (aBMD) by DXA, cortical and trabecular vBMD and microarchitecture of the radius and tibia by high resolution peripheral CT. Intra-operative bone quality was subjectively graded based on resistance to pedicle screw insertion. Post-operative complications were assessed by radiographs and CTs.

RESULTS

Among 50 women enrolled (age 65 years), mean spine aBMD was normal and 35% had osteoporosis by DXA at any site. Low aBMD and vBMD were associated with "poor" subjective intra-operative quality. Skeletal complications occurred in 46% over a median follow-up of 15 months. In Cox proportional models, complications were associated with greater number of surgical levels (HR 1.19 95% CI 1.06-1.34), smaller tibia total area (HR 1.67 95% CI1.16-2.44) and lower tibial cortical thickness (HR 1.35 95% CI 1.05-1.75; model p < 0.01).

CONCLUSION

Women with smaller bones, thinner cortices and procedures involving a greater number of vertebrae were at highest risk for post-operative complications, providing insights into surgical and skeletal risk factors for complications in this population.

Who Can Be Discharged Home after Adult Spinal Deformity Surgery?

Introduction: After adult spinal deformity (ASD) surgery, patients often require postoperative rehabilitation at an inpatient rehabilitation (IPR) center or a skilled nursing facility (SNF). However, home discharge is often preferred by patients and hsas been shown to decrease costs. In a cohort of patients undergoing ASD surgery, we sought to (1) report the incidence of discharge to home, (2) determine the factors significantly associated with discharge to home in the form of a simple scoring system, and (3) evaluate the impact of discharge disposition on patient-reported outcome measures (PROMs). Methods: A single-institution, retrospective cohort study was undertaken for patients undergoing ASD surgery from 2009 to 2021. Inclusion criteria were ≥ 5-level fusion, sagittal/coronal deformity, and at least 2-year follow-up. Exposure variables included preoperative, perioperative, and radiographic data. The primary outcome was discharge status (dichotomized as home vs. IPR/SNF). Secondary outcomes included PROMs, such as the numeric rating scales (NRSs) for back and leg pain, the Oswestry Disability Index (ODI), and EQ-5D. A subanalysis comparing IPR to SNF discharge was conducted. Univariate analysis was performed. Results: Of 221 patients undergoing ASD surgery with a mean age of 63.6 ± 17.6, 112 (50.6%) were discharged home, 71 (32.2%) were discharged to an IPR center, and 38 (17.2%) were discharged to an SNF. Patients discharged home were significantly younger (55.7 ± 20.1 vs. 71.8 ± 9.1, p < 0.001), had lower rate of 2+ comorbidities (38.4% vs. 45.0%, p = 0.001), and had less hypertension (57.1% vs. 75.2%, p = 0.005). Perioperatively, patients who were discharged home had significantly fewer levels instrumented (10.0 ± 3.0 vs. 11.0 ± 3.4 levels, p = 0.030), shorter operative times (381.4 ± 139.9 vs. 461.6 ± 149.8 mins, p < 0.001), less blood loss (1101.0 ± 977.8 vs. 1739.7 ± 1332.9 mL, p < 0.001), and shorter length of stay (5.4 ± 2.8 vs. 9.3 ± 13.9 days, p < 0.001). Radiographically, preoperative SVA (9.1 ± 6.5 vs. 5.2 ± 6.8 cm, p < 0.001), PT (27.5 ± 11.1° vs. 23.4 ± 10.8°, p = 0.031), and T1PA (28.9 ± 12.7° vs. 21.6 ± 13.6°, p < 0.001) were significantly higher in patients who were discharged to an IPR center/SNF. Additionally, the operating surgeon also significantly influenced the disposition status (p < 0.001). A scoring system of the listed factors was proposed and was validated using univariate logistic regression (OR = 1.55, 95%CI = 1.34-1.78, p < 0.001) and ROC analysis, which revealed a cutoff value of > 6 points as a predictor of non-home discharge (AUC = 0.75, 95%CI = 0.68-0.80, p < 0.001, sensitivity = 63.3%, specificity = 74.1%). The factors in the scoring system were age > 56, comorbidities ≥ 2, hypertension, TIL ≥ 10, operative time > 357 mins, EBL > 1200 mL, preop SVA > 6.6 cm, preop PT > 33.6°, and preop T1PA > 15°. When comparing IPR (n = 71) vs. SNF (n = 38), patients discharged to an SNF were significantly older (74.4 ± 8.6 vs. 70.4 ± 9.1, p = 0.029) and were more likely to be female (89.5% vs. 70.4%, p = 0.024). Conclusions: Approximately 50% of patients were discharged home after ASD surgery. A simple scoring system based on age > 56, comorbidities ≥ 2, hypertension, total instrumented levels ≥ 10, operative time > 357 mins, EBL > 1200 mL, preop SVA > 6.6 cm, preop PT > 33.6°, and preop T1PA > 15° was proposed to predict non-home discharge. These findings may help guide postoperative expectations and resource allocation after ASD surgery.

The treatment efficacy of cortical bone trajectory (CBT) pedicle screws for lumbar degenerative disease in the Chinese Han population

Purpose

To provide reference data on CBT pedicle screws from CT measurements of L1 to L5 in the Chinese Han population and to assess the treatment efficacy of CBT pedicle screws in cases of lumbar degenerative disease.

Methods

In total, 100 patients were identified from the CT database for CBT morphometric measurement of the lumbar spine. According to sex and age, patients were divided into four groups. The diameter, length, and angle of the vertebral pedicle and trajectory were measured. Then, a total of 36 patients with lumbar degenerative disease were included in this study for clinical and radiographic evaluation. Demographic characteristics, health-related quality of life (HRQOL), and extent of intervertebral disc herniation and spondylolisthesis were evaluated.

Results

The mean diameter and the mean length varied from L1 to L5 in Groups I to IV. The lateral angles ranging from L1 to L5 were 8.9 to 9.2°, 8.7 to 12.2°, 8.7 to 11.2°, and 9.2 to 10.1° in Groups I to IV, respectively. The cephalad angles from L1 to L5 were 23.5 to 28.6°, 24.7 to 26.6°, 25.0 to 28.2°, and 24.7 to 27.9° in Groups I to IV, respectively. In the case series, all patients’ neurological function and HRQOL were significantly improved at the final follow-up (p < 0.0001), and 75% of patients achieved satisfaction.

Conclusions

The morphology of the lumbar vertebral pedicle varied from L1 to L5, and the trajectory was feasible and safe. CBT pedicle screws were effective in treating lumbar degenerative diseases and benefited the patients.

Failure in Adult Spinal Deformity Surgery: A Comprehensive Review of Current Rates, Mechanisms, and Prevention Strategies

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this review is to summarize recent literature on adult spinal deformity (ASD) treatment failure as well as prevention strategies for these failure modes.

SUMMARY OF BACKGROUND DATA

There is substantial evidence that ASD surgery can provide significant clinical benefits to patients. The volume of ASD surgery is increasing, and significantly more complex procedures are being performed, especially in the aging population with multiple comorbidities. Although there is potential for significant improvements in pain and disability with ASD surgery, these procedures continue to be associated with major complications and even outright failure.

METHODS

A systematic search of the PubMed database was performed for articles relevant to failure after ASD surgery. Institutional review board approval was not needed.

RESULTS

Failure and the potential need for revision surgery generally fall into 1 of 4 well-defined phenotypes: clinical failure, radiographic failure, the need for reoperation, and lack of cost-effectiveness. Revision surgery rates remain relatively high, challenging the overall cost-effectiveness of these procedures.

CONCLUSION

By consolidating the key evidence regarding failure, further research and innovation may be stimulated with the goal of significantly improving the safety and cost-effectiveness of ASD surgery.

Caudally directed upper-instrumented vertebra pedicle screws associated with minimized risk of proximal junctional failure in patients with long posterior spinal fusion for adult spinal deformity

BACKGROUND CONTEXT

It is unknown whether upper instrumented vertebra (UIV) pedicle screw trajectory and UIV screw-rod angle are associated with development of proximal junctional kyphosis (PJK) and/or proximal junctional failure (PJF).

PURPOSE

To determine whether (1) the cranial-caudal trajectory of UIV pedicle screws and (2) UIV screw-vertebra angle are associated with PJK and/or PJF after long posterior spinal fusion in patients with adult spinal deformity (ASD).

STUDY DESIGN/SETTING

Retrospective review.

PATIENT SAMPLE

We included 96 patients with ASD who underwent fusion from T9-T12 to the pelvis (>5 vertebrae fused) between 2008 and 2015.

OUTCOME MEASURES

Pedicle screw trajectory was measured as the UIV pedicle screw-vertebra angle (UIV-PVA), which is the mean of the two angles between the UIV superior endplate and both UIV pedicle screws. (Positive values indicate screws angled cranially; negative values indicate screws angled caudally.) We measured UIV rod-vertebra angle (UIV-RVA) between the rod at the point of screw attachment and the UIV superior endplate.

METHODS

During ≥2-year follow-up, 38 patients developed PJK, and 28 developed PJF. Mean (± standard deviation) UIV-PVA was -0.9° ± 6.0°. Mean UIV-RVA was 87° ± 5.2°. We examined the development of PJK and PJF using a UIV-PVA/UIV-RVA cutoff of 3° identified by a receiver operating characteristic curve, while controlling for osteoporosis, age, sex, and preoperative thoracic kyphosis.

RESULTS

Patients with UIV-PVA ≥3° had significantly greater odds of developing PJK (odds ratio 2.7; 95% confidence interval: 1.0-7.1) and PJF (odds ratio 3.6; 95% confidence interval: 1.3-10) compared with patients with UIV-PVA <3°. UIV-RVA was not significantly associated with development of PJK or PJF.

CONCLUSIONS

In long thoracic fusion to the pelvis for ASD, UIV-PVA ≥3° was associated with 2.7-fold greater odds of PJK and 3.6-fold greater odds of PJF compared with UIV-PVA <3°. UIV-RVA was not associated with PJK or PJF.

LEVEL OF EVIDENCE

III.

Locomotive syndrome: Prevalence, surgical outcomes, and physical performance of patients treated to correct adult spinal deformity

BACKGROUND

Locomotive syndrome (LS) was proposed by the Japanese Orthopedic Association and refers to a scenario in which imminent future nursing care services will be required by elderly adults to manage the functional deterioration of their locomotive organs. It is a social imperative to clarify the risk factors and treatment strategy for LS. However, the relationship between LS and adult spinal deformity (ASD) in those who are treated with spinal corrective surgery remains largely unknown.

METHODS

Forty consecutive patients who had ASD and underwent spinal surgery for their disorder were included in this study. Locomotive dysfunction was evaluated using the 25-item Geriatric Locomotive Function Scale-25 (GLFS-25) questionnaire and physical performance tests including the one-legged standing test, the two-step test, the stand-up test, the handgrip strength, and gait speed test which were measured preoperatively, 6 months after surgery, and 1 year after surgery.

RESULTS

Of the patients with ASD treated surgically, 95% of them had LS preoperatively and LS prevalence decreased significantly 1 year after surgery by 67.5% compared with the preoperative rate. Among physical performance tests, the walking stride and one-legged standing test improved significantly after spinal corrective surgery. The GLFS-25 items for the domains of pain, mobility, and domestic life improved overall postoperatively, whereas items in the self-care domain did not and the item for difficulty in putting on and taking off trousers and pants worsened.

CONCLUSIONS

Spinal corrective surgery significantly improved physical performance tests as well as the frequency and severity of LS in patients with ASD. However, some GLFS-25 items can worsen after surgery and require attention.

Do Adult Spinal Deformity Patients Undergoing Surgery Continue to Improve From 1-Year to 2-Years Postoperative?

OBJECTIVE

Evaluate clinical improvement as measured by patient-reported outcomes (PROs) during the 1 to 2-year interval.

STUDY DESIGN

Retrospective Cohort.

METHODS

A single-institution registry of ASD patients undergoing surgery was queried for patients with ≥6 level fusions. Demographics and radiographic variables were collected. PROs collected were the ODI and SRS-22r scores at: preoperative, 1-year and 2-years. Outcome measures of clinical improvement during the 1-2 year time interval were: 1) group medians, 2) percent minimum clinically important difference (MCID), and 3) percent minimal symptom scale (MSS)(ODI < 20 or SRS-pain + function >8). Wilcoxon rank-sum tests, chi-squared tests, Kruskal-Wallis tests, and logistic regression were performed.

RESULTS

157 patients undergoing ASD surgery with minimum of 1-year follow-up were included. Mean age was 53.2 and mean instrumented levels was 13.1. Preoperative alignment was: Neutral Alignment (NA) 49%, Coronal Malalignment (CM) 17%, Sagittal Malalignment (SM 17%), and Combined Coronal/Sagittal Malalignment (CCSM) 18%. Preoperative to 1-year, and preoperative to 2-years, all ODI/SRS-22r significantly improved (P < .001). In all patients, the only significant improvement in PROs between 1-and 2-year postoperative were those reaching ODI MCID (69% 1-year vs. 84% 2-years; P < .001). Subgroup analysis: ≥55 years had an improved median ODI (18 vs. 8; P = .047) and an improved percent achieving ODI MCID (73% vs. 84%, P = .048). CCSM patients experienced significant improvement in SRS-appearance score (75% vs. 100%; P = .050), along with those with severe preoperative SM >7.5 cm (73% vs. 100%; P = .032).

CONCLUSIONS

Most ASD patients experience the majority of PRO improvement by 1-year postoperative. However, subsets of patients that may continue to improve up to 2-years postoperative include patients ≥55 years, combined coronal/sagittal malalignment, and those with severe sagittal malalignment ≥7.5 cm.

Risk Factors Associated With Failure to Reach Minimal Clinically Important Difference After Correction Surgery in Patients With Degenerative Lumbar Scoliosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to evaluate the factors affecting health-related quality of life (HRQOL) after surgery in patients with degenerative lumbar scoliosis (DLS) by minimum clinically important difference (MCID).

SUMMARY OF BACKGROUND DATA

MCID has been introduced in the adult spinal deformity to quantify the absolute minimum change that can be considered a success. There are limited data available to identify factors affecting reaching MCID after DLS surgery.

METHODS

This study reviewed a cohort of 123 DLS patients after correction surgery and with a minimum 2-year follow-up (FU). Inclusion criteria included age ≥40 and minimum five vertebrae fused and the availability of Scoliosis Research Society (SRS)-22 scores and radiographic data at baseline (BL) and FU. Using a multivariate analysis, two groups were compared to identify possible risk factors: those who reached MCID in the all four SRS domains (N = 65) at the last FU and those who missed MCID (N = 58).

RESULTS

At baseline, patients differed significantly from matched normative data in all SRS-22 domains. The baseline HRQOL was comparable in reached MCID and missed MCID group patients (P > 0.05). The HRQOL scores at FU were significantly higher than those at baseline. Of 123 included patients, 77.2% (N = 95), 72.4% (N = 89), 76.4% (N = 94), and 89.4% (N = 110) reached MCID in SRS pain, activity, appearance, and mental domain, respectively. Pelvic incidence (PI) >55°, lumbar lordosis (LL) loss >4.65°, coronal imbalance at FU, sagittal vertical axis (SVA) at FU >80 mm, and presence of proximal junctional kyphosis (PJK) and distal junctional problem (DJP) had negative effects on the recovery process.

CONCLUSION

Factors affecting reaching MCID after surgery for DLS were higher PI, LL loss, coronal imbalance, severe sagittal imbalance, and the occurrence of PJK and DJP.

LEVEL OF EVIDENCE

4.

Adult spine deformity surgery in elderly patients: are outcomes worse in patients 75 years and older?

STUDY DESIGN

Retrospective study of a prospectively collected database at one center.

OBJECTIVES

Assess the outcomes and complications of adult spinal deformity (ASD) surgery in patients that are 75 years and older compared with patients of 65-75 years of age. With increasing amounts of ASD surgery being performed on elderly patients, it is important to assess how age plays a factor in corrective reconstruction surgery.

METHODS

Inclusion criteria for the study were all patients ≥ 65 years of age that underwent thoracolumbar deformity correction involving ≥ four levels at a single institution by two surgeons. Patients were divided based on age into 65-74.9 or ≥ 75 groups. Radiographic parameters were measured preoperatively, postoperatively, and at 2 years. The Numeric Rating Scale (NRS) and Oswestry Disability Index (ODI) were collected preoperatively, at 1 year, and 2 years. Comorbidities included were based around the Charlson Comorbidity Index (CCI) and compared to the incidence of complications and need for further surgery.

RESULTS

Both age groups had improvements in their radiographic parameters postoperatively which was maintained at 2 years. Comparing the different age groups with similar comorbidity burden in regard to complications and need for additional surgery yielded no statistically significant difference between groups. Both groups had comparable decreases in NRS and increases in ODI at 2 years.

CONCLUSIONS

Analysis of our study population indicates that there is no difference between the outcomes and complications of deformity surgery in patients 75 years and older when compared to a younger elderly population. It also does not appear that a ≥ 3 comorbidity burden has a significant impact on the complications or need for additional surgery in our elderly spinal deformity surgery population.

LEVEL OF EVIDENCE

Level IV.

Group-based Trajectory Modeling: A Novel Approach to Classifying Discriminative Functional Status Following Adult Spinal Deformity Surgery: Study of a 3-year Follow-up Group

STUDY DESIGN

Retrospective review of prospectively collected database.

OBJECTIVE

To delineate and visualize trajectories of the functional status in surgically-treated adult spinal deformity (ASD) patients.

SUMMARY OF BACKGROUND DATA

Classifying long-term recovery following ASD surgery is not well defined.

METHODS

One thousand one hundred seventy-one surgically-treated patients with a minimum of 3-year follow-up were included. The group-based trajectory modeling (GBTM) was used to identify distinct trajectories of functional status over time, measured by Oswestry Disability Index (ODI). Patient profiles were then compared according to the observed functional patterns.

RESULTS

The GBTM identified four distinct functional patterns. The first group (10.0%) started with minimal disability (ODI: 15 ± 10) and ended up almost disability-free (low-low). The fourth group (21.5%) began with high ODI (66 ± 11) and improvement was minimal (high-high). Groups two (40.1%) and three (28.4%) had moderate disability (ODI: 39 ± 11 vs. 49 ± 11, P < 0.001) before surgery. Following surgery, marked improvement was seen in group two (median-low), but deterioration/no change was observed in group three (median-high). The low-low group primarily included adult idiopathic scoliosis, while the high-high group had the oldest and the most severe patients as compared with the rest of the groups. A subgroup analysis was performed between groups two and three with propensity score matching on age, body mass index, baseline physical component score (PCS), and severity of deformity. Notably, the baseline mental status of the median-high group was significantly worse than that of the median-low group, though the differences in demographics, surgery, and deformity no longer existed.

CONCLUSIONS

Patients with moderate-to-low disability are more likely to obtain better functional postoperative outcomes. Earlier surgical interventions should be considered to prevent progression of deformity, and to optimize favorable outcomes. Greatest improvement appears to occur in moderately disabled patients with good mental health. GBTM permits classification into distinct groups, which can help in surgical decision making and setting expectations regarding recovery.

LEVEL OF EVIDENCE

3.

Improvements in Back and Leg Pain After Minimally Invasive Lumbar Decompression

BACKGROUND

Few studies have quantified clinical improvement following minimally invasive lumbar decompression based on predominant back pain or leg pain.

PURPOSE

To quantify improvement in patient-reported outcomes following minimally invasive lumbar decompression and determine the degree of improvement in back pain, leg pain, and disability in patients who present with predominant back pain or predominant leg pain.

METHODS

Patients who underwent primary, one-level minimally invasive lumbar decompression for degenerative pathology were retrospectively reviewed. Comparisons of visual analog scale (VAS) back and leg pain scores, Oswestry Disability Index (ODI) scores, and Short Form-12 (SF-12) mental and physical component scores from pre-operative to 6-week, 12-week, 6-month, and 1-year follow-up. Subgroup analyses were performed for patients with predominant back pain or predominant leg pain.

RESULTS

A total of 102 patients were identified. Scores on VAS back and leg pain, ODI, and SF-12 physical component improved from pre-operative to all post-operative time points. After 1 year, patients reported a 2.8-point (47%) reduction in back pain and a 4-point (61.1%) reduction in leg pain scores; 52 patients with predominant back pain and 50 patients with predominant leg pain reported reductions in pain throughout the year following surgery. In both the back and leg pain cohorts, patients experienced reductions in ODI during the first 6 months and throughout 1-year follow-up, respectively. The majority of patients achieved minimum clinically important difference, regardless of predominant symptom.

CONCLUSIONS

Patients reported improvements in back and leg pain following minimally invasive lumbar decompression regardless of predominant presenting symptom; however, patients with predominant leg pain may experience greater improvement than those with predominant back pain.

Minimally Invasive Surgery for Mild-to-Moderate Adult Spinal Deformities: Impact on Intensive Care Unit and Hospital Stay

OBJECTIVE

To compare circumferential minimally invasive (cMIS) versus open surgeries for mild-to-moderate adult spinal deformity (ASD) with regard to intensive care unit (ICU) and hospital lengths of stay (LOS).

METHODS

A retrospective review of 2 multicenter ASD databases with 426 ASD (sagittal vertical axis <6 cm) surgery patients with 4 or more fusion levels and 2-year follow-up was conducted. ICU stay, LOS, and estimated blood loss (EBL) were compared between open and cMIS surgeries.

RESULTS

Propensity matching resulted in 88 patients (44 cMIS, 44 open). cMIS were older (61 vs. 53 years, P = 0.005). Mean levels fused were 6.5 in cMIS and 7.1 in open (P = 0.368). Preoperative lordosis was higher in open than in cMIS (42.7° vs. 40.9°, P = 0.016), and preoperative visual analog score back pain was greater in open than in cMIS (7 vs. 6.2, P = 0.033). Preoperative and postoperative spinopelvic parameters and coronal Cobb angles were not different. EBL was 534 cc in cMIS and 1211 cc in open (P < 0.001). Transfusions were less in cMIS (27.3% vs. 70.5%, P < 0.001). ICU stay was 0.6 days for cMIS and 1.2 days for open (P = 0.009). Hospital LOS was 7.9 days for cMIS versus 9.6 for open (P = 0.804).

CONCLUSIONS

For patients with mild-to-moderate ASD, cMIS surgery had a significantly lower EBL and shorter ICU stay. Major and minor complication rates were lower in cMIS patients than open patients. Overall LOS was shorter in cMIS patients, but did not reach statistical significance.

Stopping at Sacrum Versus Nonsacral Vertebra in Long Fusion Surgery for Adult Spinal Deformity: Meta-Analysis of Revision with Minimum 2-Year Follow-Up

OBJECTIVE

A pooled comparison was conducted on a revision to the sacrum (S) versus a nonsacral (NS) surgical strategy in adult spinal deformity (ASD).

METHODS

Strictly following the PRISMA 2009 guidelines, the MEDLINE, EMBASE, and Cochrane Library databases were used to search for studies published in English up to March 2018 that addressed the S versus NS surgical approach for a long fusion to treat ASD. Data on total revisions and revision reasons were extracted from the included studies and were pooled analyzed.

RESULTS

Eight retrospective studies with a total of 1846 ASD patients (528 S and 1318 NS) were included. The total revision rate was 11.38% (S: 17.80% and NS: 8.80%), and implant failure, pseudarthrosis, adjacent segment degeneration, and proximal junctional kyphosis (PJK) were common reasons for revision. The pooled results indicated that the NS group had decreased incident rates of total revision (95% confidence interval [CI] 1.20-2.32, P = 0.002; I2 = 0%) and pseudarthrosis (95% CI 2.16-15.44, P = 0.0005; I2 = 0%) compared with the S group. No significant differences were observed in implant failure (95% CI 0.86-3.90, P = 0.12; I2 = 0%), adjacent segment degeneration (95% CI 0.08-1.25, P = 0.10; I2 = 0%), and PJK (95% CI 0.54-6.88, P = 0.35; I2 = 0%) between the 2 groups.

CONCLUSIONS

Revision in ASD patients is a serious problem with a total rate of 11.38%, and implant failure, pseudarthrosis, adjacent segment degeneration, and PJK are common reasons for revision. Stopping at the sacrum vertebra in long fusion surgery on ASD patients seems to increase the incidence rates of total revision and pseudarthrosis.

Predicting Perioperative Complications in Adult Spinal Deformity Surgery Using a Simple Sliding Scale

STUDY DESIGN

A retrospective database study.

OBJECTIVE

The aim of this study was to develop and validate a sliding scale for predicting perioperative complications associated with adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

ASD surgery can have high perioperative complication rates, which is associated with increased morbidity and mortality.

METHODS

Data on consecutive ASD patients undergoing posterior corrective surgery over a 6-year interval were collected from a prospective database. The patients' preoperative general condition, surgical status, and perioperative complications occurring within 30 days of surgery were analyzed and independent predictors were determined using multivariable logistic regression analysis. We made the sliding scale using cut-off values from receiver operating curve analysis and validated the performance of this model.

RESULTS

Three hundred four patients were included with a mean age of 62.9 years. One hundred eight patients (35.5%) were affected by at least one perioperative complication with a total of 195 perioperative complications, including neurological (12.8%), excessive blood loss (11.2%), delirium (11.2%), and infection (3.6%). Total independent predictors were age [odds ratio (OR): 1.042], operation time (OPT) (OR: 2.015), and estimated blood loss (EBL) (OR: 4.885) with cut-off values of approximately 70 years, 6 hours, and 2000 mL, respectively. Fusion of ≥10 segments (OR: 2.262), three-column osteotomy (OR: 1.860), current use of antihypertensive (OR: 2.595) and anticoagulant (OR: 7.013), and body mass index (OR: 1.160) were risk factors for neurological complications, infection, and deep vein thrombosis/pulmonary thrombosis. Our proposed sliding scale had a sensitivity of 91%, specificity of 58.1%, and the incidence of perioperative complication in the validation dataset was smaller than that without this scale (P ≤ 0.05).

CONCLUSION

Patients' age, current medication, and degenerative pathology might be independent preoperative as well as operative predictors. An age and comorbidities based sliding scale with classifications of OPT and EBL may be useful for risk prediction in ASD surgery.

LEVEL OF EVIDENCE

3.

The relationship of older age and perioperative outcomes following thoracolumbar three-column osteotomy for adult spinal deformity: an analysis of 300 consecutive cases

OBJECTIVE Three-column osteotomies are increasingly being used in the elderly population to correct rigid spinal deformities. There is hesitation, however, in performing the technique in older patients because of the high risk for blood loss, longer operative times, and complications. This study assesses whether age alone is an independent risk factor for complications and length of stay. METHODS All patients with thoracolumbar adult spinal deformity (ASD) who underwent 3-column osteotomy (vertebral column resection or pedicle subtraction osteotomy) performed by the senior author from 2006 to 2016 were identified. Demographics, clinical baseline, and surgical details were collected. Outcomes of interest included perioperative complication, ICU stay, and hospital stay. Bivariate and multivariate analyses were used to assess the association of age with outcomes of interest. RESULTS A total of 300 patients were included, and 38.3% were male. The mean age was 63.7 years: 10.3% of patients were younger than 50 years, 36.0% were 50-64 years, 45.7% were 65-79 years, and 8.0% were 80 years or older. The overall mean EBL was 1999 ml. The overall perioperative complication rate was 24.7%: 18.0% had a medical complication and 7.0% had a surgical complication. There were no perioperative or 30-day deaths. Age was associated with overall complications (p = 0.002) and medical-specific complications (p < 0.001); there were higher rates of overall and medical complications with increased age: 9.7% and 6.5%, respectively, for patients younger than 50 years; 16.7% and 10.2%, respectively, for patients 50-64 years; 31.4% and 22.6%, respectively, for patients 65-79 years; and 41.7% and 41.7%, respectively, for patients 80 years or older. However, after adjusting for relevant covariates on multivariate analysis, age was not an independent factor for perioperative complications. Surgical complication rates were similar among the 4 age groups. Longer ICU and total hospital stays were observed in older age groups, and age was an independent factor associated with longer ICU stay (p = 0.028) and total hospital stay (p = 0.003). ICU stays among the 4 age groups were 1.6, 2.3, 2.0, and 3.2 days for patients younger than 50 years, 50-64 years, 65-79 years, and 80 years or older, respectively. The total hospital stays stratified by age were 7.3, 7.7, 8.2, and 11.0 days for patients younger than 50 years, 50-64 years, 65-79 years, and 80 years or older, respectively. CONCLUSIONS Older age was associated with higher perioperative complication rates, but age alone was not an independent risk factor for complications following the 3-column osteotomy for ASD. Comorbidities and other unknown variables that come with age are likely what put these patients at higher risk for complications. Older age, however, is independently associated with longer ICU and hospital stays.

After Posterior Fusions for Adult Spinal Deformity, Operative Time is More Predictive of Perioperative Morbidity, Rather Than Surgical Invasiveness: A Need for Speed?

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to determine the independent effects of operative time and surgical invasiveness on perioperative outcomes after posterior spinal fusions for adult spinal deformity.

SUMMARY OF BACKGROUND DATA

Morbidity is high after posterior fusions for adult spinal deformity. Although previous reports have demonstrated an association between perioperative outcomes and the extent of correction and fusion (number of posterior levels fused, pelvic fixation, combined anterior-posterior fusion), no study has looked at the independent effects of the surgical invasiveness after controlling for operative time.

METHODS

All adult patients, undergoing posterior spinal fusion for spinal deformity, were identified in the 2010 to 2014 National Surgical Quality Improvement Program (NSQIP) database. Multivariate analysis was used to determine the independent effects of longer operative timing and the surgical invasiveness (number of levels fused, anterior or transforaminal interbody fusions, osteotomies, and pelvic fixation) on 30-day complications.

RESULTS

A total of 1540 patients undergoing posterior spinal fusion for adult spinal deformity were identified. The overall rate of complications was 15.3%. In multivariate analysis, greater operative timing was associated with increased inpatient complications [odds ratio (95% confidence interval, 95% CI) from 2.23 (1.25-3.98) for 7-8 hours to 4.46 (2.61-7.64) for 9+ hours; P < 0.001]. Although the number of levels fused, anterior/interbody fusions, osteotomies, and pelvic fixation were associated with complications on bivariate analysis, these factors were not associated with increased complications in multivariate analysis when controlling for other factors such as operative time.

CONCLUSION

For adult deformity surgery, longer operative time appears to be a better predictor of the overall rate perioperative complications than surgical invasiveness in multivariate analysis. Rather than avoidance of a more extensive and invasive surgical procedure, which may be indicated to improve alignment and stability, these data suggest the importance of safely and efficiently minimizing overall operative time.

LEVEL OF EVIDENCE

4.

Predictors of Postoperative Recovery Based on Health-Related Quality of Life in Patients after Degenerative Lumbar Scoliosis Surgery

OBJECTIVE

To investigate the factors associated with the recovery process of elderly patients after degenerative lumbar scoliosis surgery.

METHODS

A total of 213 elderly patients who had undergone surgical treatment for degenerative lumbar scoliosis from 2011 to 2015 were included retrospectively in this study. Clinical data and demographics were collected for logistic regression analysis.

RESULTS

Among 213 eligible patients, 77 (38.5%) were classified as being in the excellent group, 70 (35%) as showing improvement, 24 (12%) as showing no change, and 29 (14.5%) as having deteriorated. At baseline, patients differed significantly from matched normative data in all Scoliosis Research Society domains. Larger differences from normative values were found for pain and activity domains. After surgery, each domain improved significantly. In the multivariate logistic regression, age 60-70 years (odds ratio [OR], 2.431; 95% confidence interval [CI], 1.143-5.174), and American Society of Anesthesiologists grade <3 (OR, 2.987; 95% CI, 1.519-5.874) may be predictive factors for a satisfying recovery, whereas presence of complications (OR, 0.342; 95% CI, 0.153-0.765), fusion to the sacrum (OR, 0.200; 95% CI, 0.076-0.523), and more osteotomies (OR, 0.360; 95% CI, 0.132-0.985) have negative effects on the recovery process.

CONCLUSIONS

The factors that affect postoperative recovery in elderly patients with degenerative lumbar scoliosis are age, American Society of Anesthesiologists grade, distal fusion level, presence of complications, and number of osteotomies.

Recovery Kinetics of Radiographic and Implant-Related Revision Patients Following Adult Spinal Deformity Surgery

BACKGROUND

Prior studies have observed similar health-related quality of life (HRQL) in revisions and nonrevision (NR) patients following adult spinal deformity (ASD) correction. However, a novel comparison approach may allow better comparisons in spine outcomes groups.

OBJECTIVE

To determine if ASD revisions for radiographic and implant-related complications undergo a different recovery than NR patients.

METHODS

Inclusion: ASD patients with complete HRQL (Oswestry Disability Index, Short-Form-36 version 2 (SF-36), Scoliosis Research Society [SRS]-22) at baseline, 6 wk, 1 yr, 2 yr. Generated revision groups: nonrevision (NR), revised-complete data (RC; with follow-up 2 yr after revision), and revised-incomplete data (RI; without 2-yr follow-up after revision). In a traditional analysis, analysis of variance (ANOVA) compared baseline HRQLs to follow-up changes. In a novel approach, integrated health state was normalized at baseline using area under curve analysis before ANOVA t-tests compared follow-up statuses.

RESULTS

Two hundred fifty-eight patients were included with 50 undergoing reoperations (19.4%). Rod fractures (n = 15) and proximal joint kyphosis (n = 9) were most common. In standard HRQL analysis, comparing RC index surgery and RC revision surgery HRQLS revealed no significant differences throughout the 2-yr follow-up from either the initial index or revision procedure. Using normalized HRQL/integrated health state, RI displayed worse scores in SF-36 Physical Component Score, SRS activity, and SRS appearance relative to NR (P &lt; .05), indicating less improvement over the 2-yr period. RC were significantly worse than RI in SF-36 Mental Component Score, SRS mental, SRS satisfaction, and SRS total (P &lt; .05).

CONCLUSION

ASD patients indicated for revisions for radiographic and implant-related complications differ significantly in their overall 2-yr recovery compared to NR, using a normalized integrated health state method. Traditional methods for analyzing revision patients' recovery kinetics may overlook delayed improvements.

Minimum Clinically Important Difference: Current Trends in the Spine Literature

STUDY DESIGN

Review of the 2011 to 2015 minimum clinically important difference (MCID)-related publications in Spine, Spine Journal, Journal of Neurosurgery-Spine, and European Spine Journal.

OBJECTIVE

To summarize the various determinations of MCID and to analyze its usage in the spine literature of the past 5 years in order to develop a basic reference to help practitioners interpret or utilize MCID.

SUMMARY OF BACKGROUND DATA

MCID represents the smallest change in a domain of interest that is considered beneficial to a patient or clinician. The many sources of variation in calculated MCID values and inconsistency in its utilization have resulted in confusion in the interpretation and use of MCID.

METHODS

All articles from 2011 to 2015 were reviewed. Only clinical science articles utilizing patient reported outcome scores (PROs) were included in the analysis. A keyword search was then performed to identify articles that used MCID. MCID utilization in the selected papers was characterized and recorded.

RESULTS

MCID was referenced in 264/1591 (16.6%) clinical science articles that utilized PROs: 22/264 (8.3%) independently calculated MCID values and 156/264 (59.1%) used previously published MCID values as a gauge of their own results. Despite similar calculation methods, there was a two- or three-fold range in the recommended MCID values for the same instrument. Half the studies recommended MCID values within the measurement error. Most studies (97.2%) using MCID to evaluate their own results relied on generic MCID. The few studies using specific MCID (MCID calculated for narrowly defined indications or treatments) did not consistently match the characteristics of their sample to the specificity of the MCID. About 48% of the studies compared group averages instead of individual scores to the MCID threshold.

CONCLUSION

Despite a clear interest in MCID as a measure of patient improvement, its current developments and uses have been inconsistent.

LEVEL OF EVIDENCE

N/A.

Lack of improvement in health-related quality of life (HRQOL) scores 6 months after surgery for adult spinal deformity (ASD) predicts high revision rate in the second postoperative year

PURPOSE

ASD is assessed radiologically with the spinopelvic parameters and clinically with HRQOL scores. The revision rate after ASD surgery is high and usually occurs during the first or second postoperative year. The aim of this study is to find clinical or radiological factors that could predict revision surgery in the second postoperative year.

MATERIALS AND METHODS

Inclusion criterion: ASD patients operated on by instrumented posterior fusion with more than 2 years follow-up were enrolled prospectively. Additional criterion was no revision surgery during the first postoperative year. From a multicenter database of 560 operated ASD patients, 164 patients met these criteria. The patients were divided into two groups depending on the need of revision surgery during the second postoperative year. Preoperative, 6-month, 1-year and 2-year data were collected and compared for both groups.

RESULTS

A total of 22 patients needed revision surgery and 142 did not. All revisions were for mechanical complications (non-fusion and implant related). Preoperatively, there was a significant difference between the groups (no revision vs. revision) for age (48 vs. 60 years), ODI (37 vs. 53), and SVA (29 vs. 76 mm), respectively. At 6 months, a significant difference in sagittal alignment was found, though HRQOL scores were similar. At 1 year, the no revision group scores improved, whereas the revision group scores remained stable or worsened. At 2 years, the no revision group scores remained stable. Comparing 6- and 12-month data, patients with improved, stable and worsened HRQOL scores had 8, 15 and 28% revision rates, respectively.

CONCLUSION

The revision rate at the second-year post-surgery (13.4%) remains high and demonstrated that a 2-year follow-up is mandatory. In addition to usual risk factors for mechanical complications in ASD surgery, stabilization or worsening of the HRQOL scores between the 6th and 12th month postop was highly predictive of revision rate. This observation is beneficial for ASD patient follow-up as clinical symptoms clearly precede mechanical failure.

Outcomes of Operative and Nonoperative Treatment for Adult Spinal Deformity

BACKGROUND:

High-quality studies that compare operative and nonoperative treatment for adult spinal deformity (ASD) are needed.

OBJECTIVE:

To compare outcomes of operative and nonoperative treatment for ASD.

METHODS:

This is a multicenter, prospective analysis of consecutive ASD patients opting for operative or nonoperative care. Inclusion criteria were age &gt;18 years and ASD. Operative and nonoperative patients were propensity matched with the baseline Oswestry Disability Index, Scoliosis Research Society-22r, thoracolumbar/lumbar Cobb angle, pelvic incidence–to–lumbar lordosis mismatch (PI-LL), and leg pain score. Analyses were confined to patients with a minimum of 2 years of follow-up.

RESULTS:

Two hundred eighty-six operative and 403 nonoperative patients met the criteria, with mean ages of 53 and 55 years, 2-year follow-up rates of 86% and 55%, and mean follow-up of 24.7 and 24.8 months, respectively. At baseline, operative patients had significantly worse health-related quality of life (HRQOL) based on all measures assessed (P &lt; .001) and had worse deformity based on pelvic tilt, pelvic incidence–to–lumbar lordosis mismatch, and sagittal vertical axis (P ⩽ .002). At the minimum 2-year follow-up, all HRQOL measures assessed significantly improved for operative patients (P &lt; .001), but none improved significantly for nonoperative patients except for modest improvements in the Scoliosis Research Society-22r pain (P = .04) and satisfaction (P &lt; .001) domains. On the basis of matched operative-nonoperative cohorts (97 in each group), operative patients had significantly better HRQOL at follow-up for all measures assessed (P &lt; .001), except Short Form-36 mental component score (P = .06). At the minimum 2-year follow-up, 71.5% of operative patients had ≥1 complications.

CONCLUSION:

Operative treatment for ASD can provide significant improvement of HRQOL at a minimum 2-year follow-up. In contrast, nonoperative treatment on average maintains presenting levels of pain and disability.

Development of Validated Computer-based Preoperative Predictive Model for Proximal Junction Failure (PJF) or Clinically Significant PJK With 86% Accuracy Based on 510 ASD Patients With 2-year Follow-up

STUDY DESIGN

A retrospective review of large, multicenter adult spinal deformity (ASD) database.

OBJECTIVE

The aim of this study was to build a model based on baseline demographic, radiographic, and surgical factors that can predict clinically significant proximal junctional kyphosis (PJK) and proximal junctional failure (PJF).

SUMMARY OF BACKGROUND DATA

PJF and PJK are significant complications and it remains unclear what are the specific drivers behind the development of either. There exists no predictive model that could potentially aid in the clinical decision making for adult patients undergoing deformity correction.

METHODS

Inclusion criteria: age ≥18 years, ASD, at least four levels fused. Variables included in the model were demographics, primary/revision, use of three-column osteotomy, upper-most instrumented vertebra (UIV)/lower-most instrumented vertebra (LIV) levels and UIV implant type (screw, hooks), number of levels fused, and baseline sagittal radiographs [pelvic tilt (PT), pelvic incidence and lumbar lordosis (PI-LL), thoracic kyphosis (TK), and sagittal vertical axis (SVA)]. PJK was defined as an increase from baseline of proximal junctional angle ≥20° with concomitant deterioration of at least one SRS-Schwab sagittal modifier grade from 6 weeks postop. PJF was defined as requiring revision for PJK. An ensemble of decision trees were constructed using the C5.0 algorithm with five different bootstrapped models, and internally validated via a 70 : 30 data split for training and testing. Accuracy and the area under a receiver operator characteristic curve (AUC) were calculated.

RESULTS

Five hundred ten patients were included, with 357 for model training and 153 as testing targets (PJF: 37, PJK: 102). The overall model accuracy was 86.3% with an AUC of 0.89 indicating a good model fit. The seven strongest (importance ≥0.95) predictors were age, LIV, pre-operative SVA, UIV implant type, UIV, pre-operative PT, and pre-operative PI-LL.

CONCLUSION

A successful model (86% accuracy, 0.89 AUC) was built predicting either PJF or clinically significant PJK. This model can set the groundwork for preop point of care decision making, risk stratification, and need for prophylactic strategies for patients undergoing ASD surgery.

LEVEL OF EVIDENCE

3.

Early experience with endoscopic foraminotomy in patients with moderate degenerative deformity

OBJECTIVE Asymmetrical degeneration of the disc is one of the most common causes of primary degenerative scoliosis in adults. Coronal deformity is usually less symptomatic than a sagittal deformity because there is less expenditure of energy and hence less effort to maintain upright posture. However, nerve root compression at the fractional curve or at the concave side of the main curve can give rise to debilitating radiculopathy. METHODS This study was a retrospective analysis of 16 patients with coronal deformity of between 10° and 20°. All patients underwent endoscopic foraminal decompression surgery. The pre- and postoperative Cobb angle, visual analog scale (VAS), 36-Item Short Form Health Survey (SF-36), and Oswestry Disability Index scores were measured. RESULTS The average age of the patients was 70.0 ± 15.5 years (mean ± SD, range 61-86 years), with a mean followup of 7.5 ± 5.3 months (range 2-14 months). The average coronal deformity was 16.8° ± 4.7° (range 10°-41°). In 8 patients the symptomatic foraminal stenosis was at the level of the fractional curve, and in the remaining patients it was at the concave side of the main curve. One of the patients included in the current cohort had to undergo a repeat operation within 1 week for another disc herniation at the adjacent level. One patient had CSF leakage, which was repaired intraoperatively, and no further complications were noted. On average, preoperative VAS and SF-36 scores showed a tendency for improvement, whereas a dramatic reduction of VAS, by 65% (p = 0.003), was observed in radicular leg pain. CONCLUSIONS Patients with mild to moderate spinal deformity are often compensated and have tolerable levels of back pain. However, unilateral radicular pain resulting from foraminal stenosis can be debilitating. In select cases, an endoscopic discectomy or foraminotomy enables the surgeon to decompress the symptomatic foramen with preservation of essential biomechanical structures, delaying the need for a major deformity correction surgery.

Influence of age on pain intensity, functional impairment and health-related quality of life before and after surgery for lumbar degenerative disc disease

BACKGROUND

Demographic changes will lead to an increase of elderly people in our population and consecutively to a higher prevalence of patients suffering from degenerative disc disease (DDD). The goal of this study was to investigate age-related differences in pain intensity, subjective and objective functional impairment and health-related quality of life (HRQoL) in patients with lumbar DDD.

METHODS

In a prospective two-center study, back and leg pain intensity (visual analogue scale (VAS)), functional impairment (Oswestry Disability Index (ODI), Roland-Morris Disability Index (RMDI)) and HRQoL (EuroQol-5D (EQ-5D), Short-Form (SF12)) were collected for consecutive patients undergoing lumbar spine surgery. Objective functional impairment (OFI) was measured using the Timed Up and Go (TUG) test. Adjusted partial correlation was used to correlate age to each scale preoperatively, as well as to the postoperative improvement at six weeks.

RESULTS

A total of n=377 patients (161 females, 42.7%) with a mean age of 58.5 years (SD 15.7, range 18.0-93.7) were included. Unadjusted TUG test raw times naturally increased with age, whereas the age-effect on standardized OFI T-scores was close to zero in patients with a lumbar disc herniation (LDH; r=-0.0666, p=0.367) or lumbar spinal stenosis (LSS; r=-0.0134, p=0.879). There was a weak correlation between age and higher ODI (LDH: r=0.1289, p=0.089; LSS: r=0.1975; p=0.027), lower EQ-5D (LSS: r=-0.1824, p=0.042) and higher RMDI by trend (LSS: r=0.1679, p=0.061). The correlation between age and postoperative improvement was negative on the VAS for back pain (LDH: r=-0.3189, p=0.026), VAS for leg pain (LDH: r=-0.3656, p=0.009) and RMDI by trend (LSS: r=-0.2004, p=0.069), as well as positive on the EQ-5D index (r=0.2412, p=0.011), indicating that younger patients showed better improvement. Due to in-group heterogeneity, no age-effect could be calculated for patients scheduled for surgical fusion.

CONCLUSIONS

The influence of age on subjective and objective measures of pain, functional impairment and HRQoL is limited for patients with LDH and LSS, but suggests an age-dependent increase of functional disability. Younger patients generally showed greater postoperative improvement at six weeks than older patients.

Prospective multicenter assessment of perioperative and minimum 2-year postoperative complication rates associated with adult spinal deformity surgery

OBJECTIVE Although multiple reports have documented significant benefit from surgical treatment of adult spinal deformity (ASD), these procedures can have high complication rates. Previously reported complications rates associated with ASD surgery are limited by retrospective design, single-surgeon or single-center cohorts, lack of rigorous data on complications, and/or limited follow-up. Accurate definition of complications associated with ASD surgery is important and may serve as a resource for patient counseling and efforts to improve the safety of patient care. The authors conducted a study to prospectively assess the rates of complications associated with ASD surgery with a minimum 2-year follow-up based on a multicenter study design that incorporated standardized data-collection forms, on-site study coordinators, and regular auditing of data to help ensure complete and accurate reporting of complications. In addition, they report age stratification of complication rates and provide a general assessment of factors that may be associated with the occurrence of complications. METHODS As part of a prospective, multicenter ASD database, standardized forms were used to collect data on surgery-related complications. On-site coordinators and central auditing helped ensure complete capture of complication data. Inclusion criteria were age older than 18 years, ASD, and plan for operative treatment. Complications were classified as perioperative (within 6 weeks of surgery) or delayed (between 6 weeks after surgery and time of last follow-up), and as minor or major. The primary focus for analyses was on patients who reached a minimum follow-up of 2 years. RESULTS Of 346 patients who met the inclusion criteria, 291 (84%) had a minimum 2-year follow-up (mean 2.1 years); their mean age was 56.2 years. The vast majority (99%) had treatment including a posterior procedure, 25% had an anterior procedure, and 19% had a 3-column osteotomy. At least 1 revision was required in 82 patients (28.2%). A total of 270 perioperative complications (145 minor; 125 major) were reported, with 152 patients (52.2%) affected, and a total of 199 delayed complications (62 minor; 137 major) were reported, with 124 patients (42.6%) affected. Overall, 469 complications (207 minor; 262 major) were documented, with 203 patients (69.8%) affected. The most common complication categories included implant related, radiographic, neurological, operative, cardiopulmonary, and infection. Higher complication rates were associated with older age (p = 0.009), greater body mass index (p ≤ 0.031), increased comorbidities (p ≤ 0.007), previous spine fusion (p = 0.029), and 3-column osteotomies (p = 0.036). Cases in which 2-year follow-up was not achieved included 2 perioperative mortalities (pulmonary embolus and inferior vena cava injury). CONCLUSIONS This study provides an assessment of complications associated with ASD surgery based on a prospective, multicenter design and with a minimum 2-year follow-up. Although the overall complication rates were high, in interpreting these findings, it is important to recognize that not all complications are equally impactful. This study represents one of the most complete and detailed reports of perioperative and delayed complications associated with ASD surgery to date. These findings may prove useful for treatment planning, patient counseling, benchmarking of complication rates, and efforts to improve the safety and cost-effectiveness of patient care.