Implant Distribution Versus Implant Density in Lenke Type 1 Adolescent Idiopathic Scoliosis: Does the Position of the Screw Matter?

STUDY DESIGN: Retrospective study. OBJECTIVE: Previous studies have demonstrated that increased implant density (ID) results in improved coronal deformity correction. However, low-density constructs with strategically placed fixation points may achieve similar coronal correction. The purpose of this study was to identify key zones along the spinal fusion where high ID statistically correlated to improved coronal deformity correction. Our hypothesis was that high ID within the periapical zone would not be associated with increased percent Cobb correction. METHODS: We identified patients with Lenke type 1 curves with a minimum 2-year follow up. The instrumented vertebral levels were divided into 4 zones: (1) cephalad zone, (2) caudal zone, (3) apical zone, and (4) periapical zone. High and low percent Cobb correction groups were compared, high percent Cobb group was defined as percent correction >67%. Total ID, total concave ID, total convex ID, and ID within each zone of the curve were compared between the groups. A multivariable analysis was performed to identify independent predictors for coronal correction. Subsequently increased and decreased thoracic kyphosis (TK) groups were compared, increased TK was defined as post-operative TK being larger than preoperative TK and decreased TK was defined as post-operative TK being less than preoperative TK. RESULTS: The cohort included 68 patients. The high percent Cobb group compared with the low percent Cobb group had significantly greater ID for the entire construct, the total concave side, the total convex side, the apical convex zone, the periapical zone, and the cephalad concave zone. The high percent Cobb group had greater pedicle screw density for the total construct, total convex side, and total concave side. In the multivariate model ID and pedicle screw density remained significant for percent Cobb correction. Ability to achieve coronal balance was not statistically correlated to ID (P = .78). CONCLUSIONS: Increased ID for the entire construct, the entire convex side, the entire concave side, and within each spinal zone was associated with improved percent Cobb correction. The ability to achieve coronal balance was not statistically influence by ID. The results of this study support that increasing ID along the entire length of the construct improves percent Cobb correction.

Staying ahead of the curve: the use of spinopelvic parameters to predict curve progression and bracing success in adolescent idiopathic scoliosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To investigate radiographic sagittal and spinopelvic parameters of patients with adolescent idiopathic scoliosis (AIS) treated with bracing and assess differences among those treated successfully and unsuccessfully. AIS is a three-dimensional deformity of the spine, sharing an intricate relationship with pelvic morphology. However, the most relevant predictors of curve progression have historically been coronal parameters and skeletal maturity. Sagittal and spinopelvic parameters have not been thoroughly investigated as predictors of curve progression and brace treatment success. METHODS: Retrospective review of AIS patients who underwent brace treatment. Coronal Cobb angles (CC), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), thoracic kyphosis (TK), lumbar lordosis (LL), and thoracic spinopelvic angles (T1SP, T9SP) were measured prior to initiation of bracing. The sagittal and spinopelvic parameters of patients requiring surgical treatment due to curve progression were compared to those treated successfully with bracing. RESULTS: No significant differences were found for age, race, gender, Risser category (0/1 vs 2/3), initial CC, TK, LL, T1SP, or T9SP between cohorts. The cohort requiring surgery had significantly lower PI (p < 0.001, 42.0 v. 54.6), SS (p < 0.001, 37.0 v. 44.5), and PT (p = 0.003, 5.0 v. 10.2) compared to those successfully treated with bracing. Multivariable models controlling for Risser stage and Initial CC revealed the odds for successful brace treatment increases with an increase in PI (OR = 1.47, CI 1.18-1.83, p < 0.001), SS (OR = 1.26, CI 1.07-1.48, p = 0.006), and PT (OR = 1.43, CI 1.09-1.86, p = 0.006) (Table 3). The odds of successful brace treatment is given per one-unit increase for each radiographic measure after adjusting for Initial CC and Risser sign which were forced into each multivariable model. CONCLUSIONS: Spinopelvic parameters may indicate potential spine adaptability and skeletal maturity. For these reasons, we proposed that spinopelvic parameters may be a potential predictor of curve progression and brace treatment success. Our results demonstrated a higher risk of curve progression with lower PI, PT, or SS which support this hypothesis, however, given the small sample size and high variability, the magnitude of this effect should be viewed with caution and should serve as an impetus to further, larger scale studies to investigate the value spinopelvic parameters in curve progression and bracing efficacy. LEVEL OF EVIDENCE: IV.

Factors Associated With Extended Length of Stay and 90-Day Readmission Rates Following ACDF.

STUDY DESIGN: Retrospective. OBJECTIVE: Identify patient risk factors for extended length of stay (LOS) and 90-day hospital readmissions following elective anterior cervical discectomy and fusion (ACDF). METHODS: Included ACDF patients from 2013 to 2017 at a single institution. Eligible patients were subset into LOS <2 and LOS ≥2 days, and no 90-day hospital readmission and yes 90-day hospital readmission. Patient and surgical factors were compared between the LOS and readmission groups. Multivariable logistic regression analysis was utilized to determine the association of independent factors with LOS and 90-day readmission rates. RESULTS: Our sample included 1896 patients; 265 (14%) had LOS ≥2 days, and 121 (6.4%) had a readmission within 90 days of surgery. Patient and surgical factors associated with LOS included patient age ≥65 years (odds ratio [OR] 1.72, 95% confidence interval [CI] 1.15-2.56), marriage (OR 0.57, 95% CI 0.43-0.79), private health insurance (OR 0.28, 95% CI 0.15-0.50), American Society of Anesthesiologists (ASA) score (OR 1.52, 95% CI 1.12-1.86), African American race (OR 1.95, 95% CI 1.38-2.72), and harvesting iliac crest autograft (OR 4.94, 95% CI 2.31-10.8). Patient and surgical factors associated with 90-day hospital readmission included ASA score (OR 1.81, 95% CI 1.32-2.49), length of surgery (OR 1.002, 95% CI 1.001-1.004), and radiculopathy as indication for surgery (OR 0.60, 95% CI 0.39-0.96). CONCLUSIONS: Extended LOS and 90-day hospital readmissions may lead to poorer patient outcomes and increased episode of care costs. Our study identified patient and surgical factors associated with extended LOS and 90-day readmission rates. In general, preoperative patient factors affected these outcomes more than surgical factors.

Periapical Wires Result in Less Curve Correction Than Pedicle Screw Constructs in Idiopathic Scoliosis.

STUDY DESIGN: Retrospective study. PURPOSE: The objective of this study was to compare percent correction between apical and periapical pedicle screw (PS) and sublaminar wire constructs for Cobb correction and coronal balance correction. OVERVIEW OF LITERATURE: The current gold standard for deformity correction in adolescent idiopathic scoliosis (AIS) are PS constructs. Sublaminar wires provide an alternative means of fixation when PS fixation cannot be safely performed. Two previous studies have compared percent curve correction between sublaminar wires and PSs, with conflicting conclusions. METHODS: The study was a retrospective review of Lenke type 1 curves with minimum follow-up of at least 1 year. Cases were divided into two groups: constructs using apical/periapical sublaminar wires (SL group) versus PS only constructs (PS group). Percent Cobb correction and coronal balance were compared between the two groups at 1 year. A multivariable regression model was used to determine the impact of apical/periapical wires on percent Cobb correction and coronal balance at 1 year when accounting for additional variables. RESULTS: The cohort included 71 patients who were predominantly female (80.2%), with average age of 14.2 years. Only 21 (29.5%) of constructs utilized apical/periapical sublaminar wires. There was a significant difference in percent Cobb correction at 1 year for the PS and SL groups (70.26% vs. 60.09%, p=0.05). No difference was observed in overall coronal balance. A multivariable model revealed that apical/periapical wires were negatively associated with percent Cobb correction at 1 year (coefficient=-8.49, p=0.023), while total implant density of the construct was positively associated with correction (coefficient=24.2, p<0.001). CONCLUSIONS: Use of PSs in the apical and periapical zones resulted in improved percent Cobb correction at 1 year in patients with AIS Lenke type 1 curves. Sublaminar wires remain a useful surgical option and result in equivalent coronal balance compared to PSs.

Neurological Sequelae and Clinical Outcomes After Lung Transplantation.

BACKGROUND: Neurological complications are common after lung transplantation. However, no large cohort studies have examined the incidence, predictors, and clinical significance of neurological events sustained by lung transplant recipients. METHODS: We conducted a retrospective cohort analysis of a consecutive series of lung transplant recipients, transplanted at Duke University Medical Center between May 2014 and February 2017 (n = 276). Early neurological complications (ie, occurring during the first week after transplant) were documented by transplant mental health specialists and included delirium, ischemic injury, and posterior reversible encephalopathy syndrome. Analyses accounted for age, native disease, sex, type of transplant, lung allocation score, and primary graft dysfunction. The objectives of the study were to characterize the prevalence and predictors of early neurological sequelae (NSE), occurring during the first week posttransplant, and the association between NSE and subsequent clinical outcomes, including length of stay and mortality. RESULTS: Neurological sequelae were common, occurring in 123 (45%) patients. Fifty-seven patients died over a follow-up interval of 2.1 years. The most common NSE were postoperative delirium (n = 110 [40%]) and posterior reversible encephalopathy syndrome (n = 12 [4%]), followed by stroke/transient ischemic attack and neurotoxicity. Higher lung allocation score was the strongest predictor of delirium. The presence of a NSE was associated with longer length of hospital stay (32 days vs 17 days, P < 0.001) and greater mortality (hazard ratio, 1.90; 95% confidence interval, 1.09-3.32], P = 0.024), with the greatest mortality risk occurring approximately 2 years after transplantation. CONCLUSIONS: Neurological events are relatively common after lung transplantation and associated with adverse clinical outcomes.