Late Infection After Spinal Fusion for Adolescent Idiopathic Scoliosis: Implant Exchange Versus Removal.

BACKGROUND: Late infection after posterior spinal arthrodesis for adolescent idiopathic scoliosis (AIS) is the leading cause of late revision. While implant removal and antibiotic therapy are usually curative, patients may experience deformity progression. The goal of this study was to compare outcomes after implant exchange (IE) or removal (IR) to treat late-onset (≥1 y postoperative) deep surgical site infection (SSI) after spinal arthrodesis in patients with AIS. METHODS: Using a multicenter AIS registry, patients who underwent posterior spinal fusion between 2005 and 2019 and developed late deep SSI treated with IE or IR were identified. Radiographic, surgical, clinical, and patient-reported outcomes at most recent follow-up were compared. RESULTS: Of 3,705 patients, 47 (1.3%) developed late infection 3.8±2.2 years (range 1 to 9.7 y) after index surgery. Mean follow-up after index surgery was 6.1 years, with 2.8 years (range 25 to 120 mo) of follow-up after revision surgery. Twenty-one patients were treated with IE and 26 with IR. At the latest follow-up, average major-curve loss of correction (1° vs 9°, P <0.001) and increase in kyphosis (1° vs. 8°, P =0.04) were smaller in the IE group than in the IR group. Two IR patients but no IE patients had reoperation. Patients who underwent IE had higher Scoliosis Research Society 22-Item Patient Questionnaire (SRS-22) total scores (4.38 vs. 3.81, P =0.02) as well as better subscores for self-image, function, and satisfaction at the latest follow-up than those who underwent IR only. There were no significant between-group differences in operative duration, estimated blood loss, length of hospital stay, or changes in SRS-22 total scores. No patient had a subsequent infection during the follow-up period. CONCLUSIONS: When treating late-onset deep SSI after posterior spinal fusion for AIS, single-stage IE is associated with better maintenance of major curve correction, sagittal profile, and patient-reported outcomes and fewer reoperations compared with IR, with no significant differences in blood loss, operative duration, or length of stay. No time interval from index surgery to IR was observed where the corrected deformity remained stable. Both techniques were curative of infection. LEVEL OF EVIDENCE: Level III.

Restoration of normal pelvic balance from surgical reduction in high-grade spondylolisthesis.

PURPOSE: To investigate the effectiveness of surgical reduction in high-grade spondylolisthesis in maintaining or restoring a normal pelvic balance, as related to the QoL. METHODS: It is a retrospective analysis of prospectively collected data of 60 patients (17 males, 43 females) aged 15 ± 3.1 years who underwent surgery for high-grade spondylolisthesis and were followed for a minimum of 2 years after surgery. Patients with a residual high-grade slip following surgery were referred to the postoperative high-grade (PHG) group, while patients with a residual low-grade slip were referred to the postoperative low-grade (PLG) group. Pelvic balance was assessed from pelvic tilt and sacral slope, in order to identify patients with a balanced pelvis or unbalanced pelvis. The SRS-22 questionnaire was completed before surgery and at last follow-up. RESULTS: Postoperatively, there were 36 patients with a balanced pelvis and 24 patients with an unbalanced pelvis. The improvement in QoL was better in patients with a postoperative balanced pelvis. There were 14 patients in the PHG group and 46 patients in the PLG group. Four of seven patients (57%) in the PHG group and 21 of 26 patients (81%) in the PLG group with a preoperative balanced pelvis maintained a balanced pelvis postoperatively (P = 0.1). None of the patients in the PHG group and 11 of 20 patients (55%) in the PLG group improved from an unbalanced to a balanced pelvis postoperatively (P < 0.05). CONCLUSIONS: Surgical reduction in high- to low-grade slip is more effective in maintaining and restoring a normal pelvic balance postoperatively. These slides can be retrieved under Electronic Supplementary Material.

Thoracic Lordosis, Especially in Males, Increases Blood Loss in Adolescent Idiopathic Scoliosis.

BACKGROUND: Intraoperative blood loss during posterior spinal fusion for adolescent idiopathic scoliosis (AIS) has been reportedly associated with multiple factors. This study aims to investigate the effect of thoracic kyphosis on blood loss in AIS spinal fusion. METHODS: Patients with AIS who underwent posterior-only procedures for Lenke I and II type curves were identified. All included patients had intraoperative tranexamic acid. Difference in estimated blood loss per blood volume (EBL/BV) was identified between hypokyphotic curves (-), normal curves (N), and hyperkyphotic curves (+) classified based on Lenke sagittal modifier. Regression analysis was then performed with EBL/BV as dependent variable. Independent variables included radiographically measured T5-T12 kyphosis and calculated 3D T5-T12 kyphosis in addition to sex, body mass index (BMI), operative time, number of fused vertebrae, number of Ponte osteotomy levels, and main thoracic coronal curve. RESULTS: In total, 837 patients were included. For female patients: EBL/BV was significantly higher for (-) (18%) compared with (N) (16%) and (+) (14%). A total of 29 female patients had T5-T12≤0 (-15 to 0 degree). EBL/BV was not significantly higher than patients with T5-T12>0 degree (18%±9% vs. 16%±11%; P=0.212). For male patients: EBL/BV was significantly higher in (-) (23%) compared with (+) (16%). In total, 14 male patients had T5-T12≤0 (-13 to 0) degree. EBL/BV was significantly higher than patients with T5-T12>0 degree (32%±18% vs. 18%±13%; P=0.015). Significant factors in predicting EBL/BV were sex, BMI, number of fused levels, and both 2D and 3D T5-T12 kyphosis. Male sex as well as every fused-level predicted an increase in EBL/BV~2%. Every 10-unit decrease in BMI predicted an increase in EBL/BV of 7%. Every 10-degree decrease in 2D or 3D T5-T12 kyphosis predicted an increase in EBL/BV~1%. The impact of the number of Ponte osteotomy levels was not significant. CONCLUSIONS: This study supports the role of sagittal thoracic alignment in affecting EBL/BV in AIS surgery. Male patients with severe thoracic lordosis (T5-T12≤0 degree) are the highest risk group for intraoperative bleeding. These findings are helpful in predicting the intraoperative blood loss for patients with AIS undergoing posterior spinal fusion. In addition to sex and number of fused levels, decreased thoracic kyphosis is associated with increased blood loss. LEVEL OF EVIDENCE: Level III-prognostic study.

Factors affecting the outcome in appearance of AIS surgery in terms of the minimal clinically important difference.

PURPOSE: The minimal clinically important difference (MCID) of the Appearance domain of the SRS-22 questionnaire is an increase ≥1.0 in surgically treated patients with adolescent idiopathic scoliosis (AIS). However, no study has sought to identify the factors associated with an SRS-22 Appearance score increase greater than the MCID at 2 years. METHODS: A retrospective analysis was performed on a prospectively collected multicenter database of 1020 surgically treated AIS patients with a minimum 2-year follow-up. Patients were divided into two cohorts: "I" = Improved after surgery (Δ Appearance ≥1.0) and "NI" = Not improved after surgery (Δ Appearance <1.0). Univariate regression was used to find a significant difference between the cohorts for individual measures. Multivariate logistic regression was used to find continuous predictors. RESULTS: 663 (65%) patients were improved greater than the MCID, and 357 were not improved (35%). The improved cohort trended toward a greater percentage of underweight patients (p = 0.074) with lower preoperative SRS Appearance scores (p < 0.001) and larger preoperative trunk shifts (p = 0.033). Postoperatively, those patients with greater percent correction of thoracic (p = 0.021) and lumbar (p = 0.003) Cobb angles, smaller apical lumbar translation (p = 0.006), and a greater correction in trunk shift (p = 0.003) were most likely to attain the MCID. CONCLUSION: Several factors influence which patients are most likely to attain the MCID following surgery for AIS. Factors such as preoperative appearance scores and body weight are patient specific; other factors such as percent correction of the thoracic and lumbar Cobb angles, trunk shift, and lumbar apical translation may be influenced by the surgeon. LEVEL OF EVIDENCE: II.

Incidence of and Risk Factors for Loss of 1 Blood Volume During Spinal Fusion Surgery in Patients With Cerebral Palsy.

BACKGROUND: Spinal fusion surgery is associated with greater blood loss in patients with cerebral palsy (CP) than in patients with adolescent idiopathic scoliosis. Risk factors for loss of 1 blood volume (LOBV) in patients with CP have not been well studied. We investigated the incidence of and risk factors for LOBV during spinal fusion surgery in young patients with CP. METHODS: We queried a multicenter registry of CP patients for all patients 21 years or younger who had undergone spinal fusion from 2008 through 2013; 272 patients met these criteria. We analyzed data on patient characteristics, preoperative laboratory values, radiographic measures, and surgical characteristics. For univariate analysis, we used χ tests and logistic regression models. Factors that were significant in the univariate analysis were used to construct a multivariate logistic regression model. Significance was set at P<0.01. RESULTS: Incidence of LOBV was 39.7%. On multivariate analysis, unit rod construct and coronal curve magnitude were significantly associated with LOBV (P<0.01). The multivariate model accounted for 32.2% of variance in LOBV. Compared with patients with pedicle screw-rod constructs, patients with unit rod constructs had 12.6-fold higher odds of LOBV (P<0.01). For each 1-degree increase in coronal curve magnitude, odds of LOBV increased 1.03-fold (P<0.01). CONCLUSIONS: In patients with CP, there is a substantial risk of LOBV during spinal fusion surgery. Use of unit rod constructs and greater preoperative coronal curves were significant risk factors for LOBV during surgery. LEVEL OF EVIDENCE: Level II.

Posterior Spinal Fusion With Pedicle Screws in Patients With Idiopathic Scoliosis and Open Triradiate Cartilage: Does Deformity Progression Occur?

BACKGROUND: Anterior-posterior spinal fusion (APSF) is the traditional treatment for patients with idiopathic scoliosis and open triradiate cartilage (OTRC). Our goals were to assess whether posterior-only spinal fusion (PSF) with pedicle screws can halt deformity progression as effectively as APSF in patients with OTRC, and whether selection of the distal fusion level influences curve progression. METHODS: We studied a prospective multicenter database to identify all children with 2-year radiographic and clinical follow-up who were 11 years or younger with Risser grade 0 and OTRC who were treated with (1) PSF (OTRC-PSF group, N=20); or (2) APSF (OTRC-APSF group, N=9). A reference group was constructed of 20 children who were 18 years or younger with Risser grade 4 or 5 and closed triradiate cartilage (CTRC) and who were treated with PSF (CTRC-PSF group) and matched in preoperative curve magnitude and type to the OTRC-PSF group. The 3 groups were compared with respect to operative time, blood loss, length of hospital stay, and radiographic and functional outcomes (significance, P<0.05). RESULTS: OTRC-APSF patients had significantly longer operative time (P<0.01), greater blood loss (P=0.02), and longer hospital stays (P<0.01) than OTRC-PSF patients. At 2 years, 7 (35%) OTRC-PSF patients had >10 degrees of curve progression compared with no patients in the OTRC-APSF group (P=0.042) and 1 patient in the CTRC-PSF group (P=0.018). The OTRC-PSF group had the highest number of patients fused to the stable vertebra. Of the 11 OTRC-PSF patients fused to 1 vertebra short of stable, 6 (55%) had >10 degrees of curve progression. Of the 9 OTRC-PSF patients fused to at least the stable vertebra or lower, only 1 (11%) had curve progression. There were no significant differences in Scoliosis Research Society outcome scores between OTRC-PSF patients who did and those who did not have >10 degrees of curve progression. CONCLUSIONS: PSF with pedicle screws was associated with curve progression in a significantly greater proportion of patients with OTRC compared with APSF. Not fusing to stable was also associated with curve progression in patients treated with PSF but not APSF. LEVEL OF EVIDENCE: Level III-therapeutic.

Recurrence of rib prominence following surgery for adolescent idiopathic scoliosis with pedicle screws and direct vertebral body derotation.

PURPOSE: Pedicle screw constructs combined with direct vertebral body derotation (DVBD) provide a powerful corrective force of the rib prominence associated with adolescent idiopathic scoliosis (AIS). We wished to evaluate the incidence and correlative factors associated with recurrence of rib prominence (RRP) developing postoperatively despite adequate initial correction. METHODS: 103 patients with AIS underwent pedicle screw fixation with DVBD without thoracoplasty and had postoperative scoliometer readings at 6, 12, and 24 months. Patients with RRP, defined as a postoperative scoliometer increase ≥5°, were compared to those without recurrence. RESULTS: The mean rib prominence measured 14.0 ± 4.3° preoperatively, with a correction of 50.3 ± 26.7 % at 6 months, 49.0 ± 39.0 % at 1 year, and 49.1 ± 26.7 % at 2 years. RRP was identified in 15.5 % of the patients with a correction of 57.5 ± 25.5 % at 6 months, 47.2 ± 42.5 % at 1 year, and 40.4 ± 21.6 % at 2 years. At 2 years, the RRP group demonstrated a significantly larger major coronal Cobb (p < 0.05) and a trend towards less curve correction (p = 0.09). Patients with open triradiates had a significantly higher rate of RRP compared to those with closed (p = 0.01). Worsening apical vertebral rotation at 2 years post-operation occurred in 43.8 % (7/16) of the patients with RRP. CONCLUSION: RRP after posterior fusion for AIS with all pedicle screw constructs and DVBD occurred in 15.5 % of patients in our study. Patients with open triradiate cartilage had a significantly higher rate of RRP, although most with RRP were skeletally mature. There was a trend towards loss of coronal correction and increased apical vertebral rotation at 2 years in patients with RRP. The potential for RRP after adequate initial correction should be discussed with patients. LEVEL OF EVIDENCE: 2.

Is there a role for the 5-degree rule in adolescent idiopathic scoliosis?

BACKGROUND: Nonstructural curves are defined in the Lenke classification system for adolescent idiopathic scoliosis as bending out to <25 degrees. A caveat in the original paper states, however, that if the difference in Cobb magnitude between the major and minor curves is <5 degrees, then the minor curve should be considered structural, regardless of its Cobb magnitude. It is unclear whether following this rule affects patient outcomes. METHODS: A multicenter retrospective study using a prospectively collected database was performed on surgical adolescent idiopathic scoliosis patients, with 2 years of minimum follow-up. All the lumbar curves measured <25 degrees on bending x-ray. Curves (major and minor) that were within <5 degrees of each other were analyzed in 2 treatment subsets: nonselective fusion (NS) and selective thoracic fusion (STF1), and compared with similar selective fusion cases with false double major curves with a lumbar curve between 5 and 10 degrees less in magnitude than the thoracic curve magnitude (STF2). Preoperative and 2-year postoperative radiographic and SRS-22 parameters were compared. RESULTS: Of 58 patients, there were 14 NS, 11 STF1, and 33 STF2. NS had larger preoperative curves than STF1, but achieved better lumbar correction (58%) than STF1 (32%) or STF2 (41%) (P=0.004). STF1 tended to have more preoperative coronal imbalance than STF2 (-2.26 vs. -1.12 cm) (P=0.066) but were similar at 2 years. Preoperative thoracic rib prominence measures were similar for all groups, but NS had significantly worse rib prominence than STF1 (NS: 8.4 vs. STF1: 4.4, P=0.046) at 2 years. There were no differences among the 3 groups in SRS-22 scores preoperatively and at 2 years. CONCLUSIONS: Almost half of the cases with curves within <5 degrees of each other did not follow the 5-degree rule, suggesting that there is variability among surgeons in their definition of what is truly structural. Selective thoracic fusion cases behaved similarly regardless of whether or not the curves were within 5 degrees of each other. The results of our analysis of the 5-degree caveat challenge its utility as a criterion for defining structural curves. LEVEL OF EVIDENCE: Level II.

Fifteen Years of Spinal Fusion Outcomes in Children With Cerebral Palsy: Are We Getting Better?

STUDY DESIGN: Retrospective multicenter study. OBJECTIVE: We reviewed 15-year trends in operative factors, radiographic and quality of life outcomes, and complication rates in children with cerebral palsy (CP)-related scoliosis who underwent spinal fusion. SUMMARY OF BACKGROUND DATA: Over the past two decades, significant efforts have been made to decrease complications and improve outcomes of this population. MATERIALS AND METHODS: We retrospectively reviewed a multicenter registry of pediatric CP patients who underwent spinal fusion from 2008 to 2020. We evaluated baseline and operative, hospitalization, and complication data as well as radiographic and quality of life outcomes at a minimum 2-year follow-up. RESULTS: Mean estimated blood loss and transfusion volume declined from 2.7±2.0 L in 2008 to 0.71±0.34 L in 2020 and 1.0±0.5 L in 2008 to 0.5±0.2 L in 2020, respectively, with a concomitant increase in antifibrinolytic use from 58% to 97% (all, P <0.01). Unit rod and pelvic fusion use declined from 33% in 2008 to 0% in 2020 and 96% in 2008 to 79% in 2020, respectively (both, P <0.05). Mean postoperative intubation time declined from 2.5±2.6 to 0.42±0.63 days ( P< 0.01). No changes were observed in preoperative and postoperative coronal angle and pelvic obliquity, operative time, frequency of anterior/anterior-posterior approach, and durations of hospital and intensive care unit stays. Improvements in the Caregiver Priorities and Child Health Index of Life with Disabilities postoperatively did not change significantly over the study period. Complication rates, including reoperation, superficial and deep surgical site infection, and gastrointestinal and medical complications remained stable over the study period. CONCLUSIONS: Over the past 15 years of CP scoliosis surgery, surgical blood loss, transfusion volumes, duration of postoperative intubation, and pelvic fusion rates have decreased. However, the degree of radiographic correction, the rates of surgical and medical complications (including infection), and health-related quality of life measures have broadly remained constant.

Representation and Race in Adolescent Idiopathic Scoliosis Research: Disparities in Curve Magnitude and Follow-Up.

STUDY DESIGN: Prospective Cohort Study. OBJECTIVE: The present study aims to determine if the racial representation of patients enrolled in a large prospective scoliosis registry is reflective of the general United States population. Further, we studied whether there was an association between race, pre-operative parameters, outcomes and loss to follow-up. METHODS: Prospectively collected data for patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS) was reviewed, including self-reported race/ethnicity. The U.S. pediatric population and U.S. patients enrolled in the prospective registry were compared. The data obtained was analyzed for variations between races, for pre-operative variables and follow-up. RESULTS: Of the 2210 included patients in the registry 66% of patients reported as White, while 52% of the 2018 U.S. pediatric population reported as White. 15% of the registry reported as Hispanic/Latino compared to 22% of the U.S. pediatric population, 13% Black compared to 14% of the U.S. pediatric population, and 4% Asian compared to 5% of the U.S. pediatric population. Asian and White patients had statistically significant higher 2-year follow-up in all but one of six enrollment sites (P < 0.001). Native American, Other, and Hispanic/Latino patients had the highest BMIs. Native American and Black patients had the highest pre-op thoracic Cobb angles. Pre-op ages of Black, Hispanic, and Native American patients were statistically lower (P < 0.01). CONCLUSION: This study demonstrates the association between race and patient follow-up and pre-operative factors in patients who underwent surgery for AIS. Black, Native American, and Hispanic populations were underrepresented both at pre-op and follow-up when compared to their relative proportion in the U.S. pediatric population.

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 pedicle screw fixation on loss of deformity correction in patients with adolescent idiopathic scoliosis.

BACKGROUND: Loss of coronal correction has been reported in the presence of a solid posterior fusion mass in patients who are skeletally immature. Significant increases in postoperative coronal curvature are typically attributed to the presence of pseudarthrosis, loss of instrumentation fixation, or adding-on. We evaluated the clinical and radiographic factors associated with a loss of correction that was not attributed to these etiologies as well as the impact of pedicle screw fixation on loss of correction. METHODS: A prospective, longitudinal study database was retrospectively queried for patients with at least 2 years of follow-up who underwent surgery for adolescent idiopathic scoliosis. Loss of correction was defined (1) clinically, as a >5 degree increase in the inclinometer reading at any time interval after surgery, excluding preoperative values; or (2) radiographically, as an increase of ≥ 10 degrees in the coronal Cobb angle of an instrumented curve. Patients with pseudarthrosis, adding-on, or loss of fixation were excluded. RESULTS: Ninety-three of 800 patients (11.6%) had loss of deformity correction. Twenty-one patients (2.5%) had >5 degrees of inclinometer change and 76 patients (9.5%) had ≥10 degrees of Cobb change, with a mean loss of 10.85±4.2 degrees. When comparing pedicle screw constructs only, 10% of patients developed loss of correction as opposed to 20% of the patients with hybrid constructs (P=0.036). Factors associated with loss of correction were: age, hybrid construct, magnitude of thoracic curve, thoracic apical translation, and T1 tilt angle. CONCLUSION: This study reports a high percentage of loss of coronal correction (12%) after 2 years of follow-up that was not associated with infection, adding-on, or apparent pseudarthrosis. Larger magnitude thoracic curves with apical deviation and hybrid constructs were associated with an increased likelihood of loss of curve correction where use of pedicle screw fixation seems to decrease its incidence. LEVEL OF EVIDENCE: III.

Machine Learning for Benchmarking Adolescent Idiopathic Scoliosis Surgery Outcomes.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The aim of this study was to design a risk-stratified benchmarking tool for adolescent idiopathic scoliosis (AIS) surgeries. SUMMARY OF BACKGROUND DATA: Machine learning (ML) is an emerging method for prediction modeling in orthopedic surgery. Benchmarking is an established method of process improvement and is an area of opportunity for ML methods. Current surgical benchmark tools often use ranks and no "gold standards" for comparisons exist. MATERIALS AND METHODS: Data from 6076 AIS surgeries were collected from a multicenter registry and divided into three datasets: encompassing surgeries performed (1) during the entire registry, (2) the past 10 years, and (3) during the last 5 years of the registry. We trained three ML regression models (baseline linear regression, gradient boosting, and eXtreme gradient boosted) on each data subset to predict each of the five outcome variables, length of stay (LOS), estimated blood loss (EBL), operative time, Scoliosis Research Society (SRS)-Pain and SRS-Self-Image. Performance was categorized as "below expected" if performing worse than one standard deviation of the mean, "as expected" if within 1 SD, and "better than expected" if better than 1 SD of the mean. RESULTS: Ensemble ML methods classified performance better than traditional regression techniques for LOS, EBL, and operative time. The best performing models for predicting LOS and EBL were trained on data collected in the last 5 years, while operative time used the entire 10-year dataset. No models were able to predict SRS-Pain or SRS-Self-Image in any useful manner. Point-precise estimates for continuous variables were subject to high average errors. CONCLUSIONS: Classification of benchmark outcomes is improved with ensemble ML techniques and may provide much needed case-adjustment for a surgeon performance program. Precise estimates of health-related quality of life scores and continuous variables were not possible, suggesting that performance classification is a better method of performance evaluation.

Effect of direct vertebral body derotation on the sagittal profile in adolescent idiopathic scoliosis.

PURPOSE: We sought to clarify the effect of applying derotation maneuvers in the correction of adolescent idiopathic scoliosis (AIS) on the sagittal plane. METHODS: We retrospectively queried a large, multicenter, prospectively collected database for patients who underwent surgical correction of AIS. All patients had at least 2 years of follow-up and documentation as to whether or not a derotation maneuver was performed during surgery. All patients underwent posterior spinal fusion with pedicle screw constructs. Patients who underwent concurrent anterior procedures were excluded. RESULTS: A total of 323 patients were identified, of whom 66 did not have direct vertebral body derotation (DVBD) maneuvers applied during the deformity correction. The remaining 257 had a vertebral body derotation maneuver performed during their surgical correction. Although no significant differences were identified between the two groups when comparing pre-op and post-op thoracic kyphosis using T2-12 and T5-12 endplates, the absolute change in angulation measured from T2-12 was significantly different between the two groups. Postoperatively, the derotation group had a mean decrease in thoracic kyphosis of 5.1±15.3° as compared to 10.8±18.9° in the control group, P = 0.03. CONCLUSION: Although patients in both groups had decreased mean thoracic kyphosis postoperatively, application of DVBD in the correction of scoliosis did not additionally worsen the sagittal profile.

Factors associated with increased back pain in primary thoracic adolescent idiopathic scoliosis 10 years after surgery.

PURPOSE: To identify the prevalence and predictors of nonspecific back pain in primary thoracic adolescent idiopathic scoliosis (AIS) patients at 10 years after surgery. METHODS: This was a case-control multi-center study. A query of patients who underwent surgical correction of major thoracic AIS between 1997 and 2007 with 10-year follow-up was reviewed. SRS-22 pain scores at 10 years were classified as below normal (≤ 2 standard deviations below average for controls of similar age/sex from published literature) or within/above the control range. RESULTS: One hundred and seventy-one patients with an average of 10.5 ± 0.8-years follow-up were included. Average age at surgery was 14 ± 2 years. The rate of pain was 23% for males and 11% for females (p = 0.08). Differences in age, 10-year SRS mental health score, and radiographic measures were noted. Of 12 patients who underwent revision surgery, 42% reported below normal pain scores versus 11% in cases without revision (p = 0.012). Classification and regression tree (CART) analysis identified 10-year thoracic curve magnitude and 10-year mental health scores as significant predictors. Thoracic Cobb of ≤ 26° at 10 years was associated with a 7% rate of below normal pain scores compared to 27.5% when the curve was > 26° (OR = 4.8, p < 0.05). Of those with a curve ≤ 26°, no patients had abnormal pain if the SRS mental health score was > 4.2 and 15% had more pain than normal if mental health score was ≤ 4.2 (OR 23, p < 0.05). CONCLUSION: Increased primary thoracic curve magnitude (> 26°) at 10 years was the primary predictor of increased pain. For patients with less coronal deformity (< 26°), a poor mental health score was associated with an increased rate of pain. Male gender and revision surgery may also play a role in increased pain, however, the overall frequency of these variables were low. LEVEL OF EVIDENCE: Level 3.

Risk factors for gastrointestinal complications after spinal fusion in children with cerebral palsy.

DESIGN: Prospective cerebral palsy (CP) registry review. OBJECTIVES: (1) Evaluate the incidence/risk factors of gastrointestinal (GI) complications in CP patients after spinal fusion (SF); and (2) investigate the validity of the modified Clavien-Dindo-Sink classification. BACKGROUND: Perioperative GI complications result in increased length of stay (LOS) and patient morbidity/mortality. However, none have analyzed the outcomes of GI complications using an objective classification system. METHODS: A prospective/multicenter CP database identified 425 children (mean, 14.4 ± 2.9 years; range, 7.9-21 years) who underwent SF. GI complications were categorized using the modified Clavien-Dindo-Sink classification. Grades I-II were minor complications and grades III-V major. Patients with and without GI complications were compared. RESULTS: 87 GI complications developed in 69 patients (16.2%): 39 minor (57%) and 30 major (43%). Most common were pancreatitis (n = 45) and ileus (n = 22). Patients with preoperative G-tubes had 2.2 × odds of developing a GI complication compared to oral-only feeders (OR 2.2; 95% CI 0.98-4.78; p = 0.006). Similarly, combined G-tube/oral feeders had 6.7 × odds compared to oral-only (OR 6.7; 95% CI 3.10-14.66; p < 0.001). The likelihood of developing a GI complication was 3.4 × with normalized estimated blood loss (nEBL) ≥ 3 ml/kg/level fused (OR 3.41; 95% CI 1.95-5.95; p < 0.001). Patients with GI complications had more fundoplications (29% vs. 17%; p = 0.03) and longer G-tube fasting periods (3 days vs. 2 days; p < 0.001), oral fasting periods (5 days vs. 2 days; p < 0.001), ICU admissions (6 days vs. 3 days; p = 0.002), and LOS (15 days vs. 8 days; p < 0.001). LOS correlated with the Clavien-Dino-Sink classification. CONCLUSION: Gastrointestinal complications such as pancreatitis and ileus are not uncommon after SF in children with CP. This is the first study to investigate the validity of the modified Clavien-Dindo-Sink classification in GI complications after SF. Our results suggest a correlation between complication severity grade and LOS. The complexity of perioperative enteral nutritional supplementation requires prospective studies dedicated to enteral feeding protocols. LEVEL OF EVIDENCE: Therapeutic-level III.

The Benefits of Sparing Lumbar Motion Segments in Spinal Fusion for Adolescent Idiopathic Scoliosis Are Evident at 10 Years Postoperatively.

STUDY DESIGN: A prospective multicenter study. OBJECTIVE: To evaluate the effects of sparing lumbar motion segments on spinal mobility and Scoliosis Research Society-22 scores at 10 years after spinal fusion for major thoracic adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: In surgical correction for major thoracic AIS, the long-term benefits of sparing lumbar motion segments remain unclear. METHODS: A prospective multicenter registry was reviewed and patients with major thoracic AIS (Lenke types 1-4) and availability of both preoperative and 10-year postoperative mobility data were included. Spinal fusions ending at L1 or above were defined as thoracic fusions (T), and at L2 or below as thoracic and lumber fusions (T + L). Spinal mobility was evaluated with a measuring tape. The excursions between the starting and ending positions were measured using the distance from the spinous processes of C7 to S1 for forward flexion (FF), and the distance from the tip of the middle finger to the floor for lateral flexion (LF). Substantial reduction of mobility was defined as a reduction rate (a ratio of postoperative change divided by preoperative mobility) of 40% or more. Motion data were correlated with lowest instrumented vertebra levels and group comparisons were performed. RESULTS: We identified 151 patients (average age, 25.1 years). The spinal mobility decreased with more distal lowest instrumented vertebrae (FF, rho = 0.208; right LF, 0.257; left LF, 0.371; P ≤ 0.01). Consequently, the incidence of substantial reduction of mobility was lower in the T group (n = 109) than in the T + L group (n = 42) (FF: 17.4% vs. 50%, LF: 14.8% vs. 51.2%; P < 0.001). Patients with substantial reduction in LF had lower Scoliosis Research Society-22 scores for pain, function, satisfaction, and total scores than those without substantial reduction at 10-year follow-up (P < 0.05). CONCLUSION: The sparing of lumbar motion segments demonstrated clinically significant benefits at 10-year postoperatively. LEVEL OF EVIDENCE: 2.

Comparing short-term AIS post-operative complications between ACS-NSQIP and a surgeon study group.

STUDY DESIGN: Prospective cohort review. OBJECTIVE: To compare two AIS databases to determine if a performance improvement-based surgeon group has different outcomes compared to a national database. The American College of Surgeon's National Quality Improvement Program (ACS-NSQIP) and a surgeon study group (SG) collect prospective data on AIS surgery outcomes. NSQIP offers open enrollment to all institutions, and SG membership is limited to 15 high-volume institutions, with a major initiative to improve surgeon performance. While both provide important outcome benchmarks, they may reflect outcomes that are not relatable nationwide. METHODS: The ASC-NSQIP Pediatric Spine Fusion and SG database were queried for AIS 30- and 90-day complication data for 2014 and 2015. Prospective enrollment and a dedicated site coordinator with rigorous data quality assurance protocols existed for both registries. Outcomes were compared between groups with respect to superficial and deep surgical site infections (SSI), neurologic injury, readmission, and reoperation. RESULTS: There were a total of 2927 AIS patients included in the ASC-NSQIP data and 721 in the SG database. Total complication rate was 9.4% NSQIP and 3.6% SG. At 90 days, there were fewer surgical site infections reported by SG than ASC-NSQIP (0.6% vs. 1.6%, p = 0.03). Similarly, there were less spinal cord injuries (0.8% vs 1.5%, p = 0.006), 30-day readmissions (0.8% vs. 2.6%, p = 0.002), and 30-day reoperations (0.6% vs. 1.7%, p = 0.02) in the SG cohort. CONCLUSIONS: Comparison of these two data sets suggests a range of complications and readmission rates, with the SG demonstrating lower values. These results are likely multi-factorial with the performance improvement initiative of the SG playing a role. Understanding the rate and ultimate risk factors for readmission and complications from big data sources has the potential to further drive quality improvement. LEVEL OF EVIDENCE: III.

The variability in the management of acute surgical site infections: an opportunity for the development of a best practice guideline.

BACKGROUND: Multiple studies have reported on the risks and preventative measures associated with acute surgical site infection (SSI) in patients with adolescent idiopathic scoliosis (AIS). Few studies have evaluated treatment and results. The purpose of this study was to evaluate the need for development of best practice guidelines based on the management of an acute SSI across 9 different centers. METHODS: A prospectively collected, multicenter database of patients undergoing surgical correction of AIS was reviewed for all acute SSI. Infection characteristics, treatment methods, and outcomes were summarized. RESULTS: Twenty-three (0.6%) from a total of 3926 AIS patients were treated for an acute SSI, all of which resolved. Twenty patients had documentation of the infection treatment (10 deep infections, 10 superficial). All ten patients with deep infections underwent operative incision and drainage. Six patients ultimately found to have a superficial infection underwent I&D and another 3 had dressing changes in the office. In the deep group, one patient had instrumentation exchanged and seven patients had bone graft removed. All 16 patients who underwent operative I&D had cultures obtained with 11 positive cultures. All deep infection patients were started on IV antibiotics for 2 days to 6 weeks prior to conversion to oral antibiotics. Five of six operative superficial infections were begun on IV antibiotics with conversion to oral antibiotics. Total antibiotic administration ranged from 5 days to 7 months in the deep infection group and 1 to 6 weeks in the superficial group. CONCLUSIONS: While deep infections are consistently treated with I&D, there is significant variability in the surgical and medical management of acute SSI. Considering the universal resolution of the infection, there is opportunity for the development of BPG to minimize treatment morbidity and cost, while optimizing outcomes for this major complication. LEVEL OF EVIDENCE: Therapeutic-IV.

Prospective 10-year follow-up assessment of spinal fusions for thoracic AIS: radiographic and clinical outcomes.

STUDY DESIGN: Prospective registry. The evolution of spinal instrumentation has provided better outcomes in adolescent idiopathic scoliosis (AIS); however, there is a paucity of reliable prospective information on 10-year post-operative outcomes of modern surgical techniques. METHODS: A prospective multicenter registry of patients who had surgical correction of AIS was reviewed. Patients with major thoracic scoliosis (Lenke types 1-4) operated on between 1997 and 2007, with 10-year post-operative follow-up data were included. Radiographic and clinical outcomes including Scoliosis Research Society (SRS)-22 scores and revision surgeries were evaluated. RESULTS: One hundred and seventy-four patients (mean 25.0 years of age at most recent evaluation) were included. Pedicle screw constructs were used in 102 patients (58%), hook or hybrid constructs in 22 (13%), and anterior screw-rod constructs in 50 (29%). The mean pre-operative thoracic Cobb angle was corrected from 53° to 18° initially. At 10-year follow-up, the mean thoracic curve was 22° (mean 57% correction), with 29 patients (16.7%) having loss of correction (LOC) ≥ 10°. There were a total of 14 revision surgeries performed in 13 patients (7.5%). SRS-22 pain (p = 0.035), self-image (p < 0.001), and total scores (p < 0.001) significantly improved at 2-year follow-up. The mean pain score at 10-year follow-up was similar to pre-operative scores and lower (more pain) than previously published mean scores of normal adults aged 20-40 years (p < 0.05). CONCLUSIONS: Spinal fusion patients report SRS-22 quality of life 10 years after scoliosis surgery that is minimally reduced compared to healthy peers and substantially better than an un-operated cohort of comparably aged scoliosis patients. Adolescents with thoracic idiopathic scoliosis should expect little if any change in their health-related quality of life compared to before surgery, high satisfaction, and a 7.5% chance of revision surgery 10 years after their index spinal fusion. LEVEL OF EVIDENCE: Therapeutic II.