Publications by authors named "Christopher Ames"

Patients with proximal junctional kyphosis (PJK) or failure (PJF) may demonstrate disparate outcomes and recovery when fused to the upper (UT) versus lower (LT) thoracic spine. Few studies have distinguished the reoperation and recovery abilities of patients with PJK or PJF when fused to the upper (UT) versus lower (LT) thoracic spine. Adult spine deformity patients ≥ 18 yrs with preoperative and 5-year (5Y) data fused to the sacrum/pelvis were included.

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Objective: Malalignment following cervical spine deformity (CSD) surgery can negatively impact outcomes and increase complications. Despite the growing ability to plan alignment, it remains unclear whether preoperative goals are achieved with surgery. The objective of this study was to assess how good surgeons are at achieving their preoperative goal alignment following CSD surgery.

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Study Design: Retrospective analysis of prospectively-collected data.

Objective: This study aims to define clinically relevant blood loss in adult spinal deformity (ASD) surgery.

Background: Current definitions of excessive blood loss following spine surgery are highly variable and may be suboptimal in predicting adverse events (AE).

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Article Synopsis
  • The study investigates how different reasons for revision surgery in adult spinal deformity (ASD) patients affect their postoperative outcomes, revealing a high incidence of reoperations.
  • A sample of 891 ASD patients was analyzed retrospectively, categorizing their revisions by cause, and assessing complications, radiographic results, and disability metrics.
  • Findings suggest that different etiologies (mechanical, infection, wound, and SI pain) lead to varying outcomes, with mechanical issues showing less improvement over time compared to others.
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Background And Objectives: The spectrum of patients requiring adult spinal deformity (ASD) surgery is highly variable in baseline (BL) risk such as age, frailty, and deformity severity. Although improvements have been realized in ASD surgery over the past decade, it is unknown whether these carry over to high-risk patients. We aim to determine temporal differences in outcomes at 2 years after ASD surgery in patients stratified by BL risk.

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Objective: The objective of this study was to identify baseline patient and surgical factors predictive of optimal outcomes in staged versus same-day combined-approach surgery.

Methods: Adult spinal deformity (ASD) patients with baseline and perioperative (by 6 weeks) data were stratified based on single-stage (same-day) or multistage (staged) surgery, excluding planned multiple hospitalizations. Means comparison analyses were used to assess baseline demographic, radiographic, and surgical differences between cohorts.

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Objective: The goal of this study was to assess the impact of fractional curve (FC) severity on curve progression and postoperative outcomes in patients undergoing adult idiopathic scoliosis (AdIS) correction.

Methods: Patients with AdIS who had preoperative coronal plane deformity and who had undergone thoracolumbar fusion with a lowermost instrumented vertebra (LIV) between L1 and L4 were included. Patients were stratified by 6-week postoperative FC severity (small FC, ≤ 40th percentile, large FC, ≥ 60th percentile of the entire cohort; calculated as the Cobb angle between LIV and S1) and age groups.

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Article Synopsis
  • Understanding preoperative deformity in lumbar spine revisions can help improve outcomes and prevent failures in future surgeries.
  • A study compared patients with no prior surgery (PRIMARY) and those with short (SHORT) or long (LONG) fusions, highlighting how different failure modes correlate with shorter fusions.
  • Results showed that revision patients experienced significant alignment issues and often required more invasive correction techniques, indicating a need for better alignment strategies in future operations.
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Article Synopsis
  • The study is a retrospective cohort analysis aimed at assessing the surgical outcomes of adult spinal deformity using AI-based clustering to categorize patients into different deformity types, including Moderate Sagittal, Severe Sagittal, Coronal, and Hyper-Thoracic Kyphosis.
  • A total of 1062 patients were analyzed, showing that while all deformity clusters experienced similar improvements in health-related quality of life after surgery, those in the Severe Sagittal cluster had notably higher complication rates, especially regarding major complications, reoperations, and implant failures.
  • Despite varying complication rates among clusters, the types of complications did not show significant differences, indicating that all clusters benefit equally from surgical interventions, achieving comparable rates of minimal clinically important difference in quality
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Purpose: Spine deformity surgery is a complex multi-step procedure that has a relatively high complication rate. The use of surgical safety checklists has been shown to reduce perioperative adverse events, but existing lists are varied and non-specific for spinal deformity surgery. Thus, the purpose of this study was to develop a comprehensive surgical checklist for complex spinal corrective surgery.

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Article Synopsis
  • - The study is a secondary data analysis of an NIH-sponsored research focusing on cost-effectiveness between surgical and non-surgical treatments for Adult Symptomatic Lumbar Scoliosis (ASLS) eight years post-enrollment.
  • - Previous analyses at the five-year mark showed a cost-effectiveness ratio (ICER) of $44,033 (As-Treated) and $27,480 (Intent-to-treat), while the current eight-year data suggests that surgical treatment is more economically favorable, with an ICER of $20,569 per Quality Adjusted Life Year (QALY) gained.
  • - The conclusion highlights that operative treatment for ASLS presents a more cost-effective option compared to non-operative treatment, as indicated
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  • Tranexamic acid (TXA) is used in adult spinal deformity surgery to reduce blood loss, but there's no agreed-upon dosing method.
  • A study analyzed data from 265 complex ASD patients, categorizing them into low, medium, and high TXA dose groups and measuring blood loss, complications, and RBC transfusions.
  • Findings revealed that lower TXA doses resulted in significantly higher blood loss and increased RBC transfusions compared to high doses, suggesting that higher TXA dosing may be more effective in minimizing blood loss during surgery.
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  • This multicentric retrospective study aimed to establish normative values for proximal junctional angles (PJA) in adult spinal deformity (ASD) surgery patients, using data from healthy volunteers for comparison.
  • The study analyzed data from 721 healthy individuals and 824 ASD surgery patients, assessing the rates of abnormal PJA values and comparing them with the rates of proximal junctional kyphosis (PJK) using different definitions.
  • Findings revealed significant differences in PJK rates based on the criteria used, highlighting the need for more precise level-adjusted assessments of PJA values to better define abnormalities and challenge traditional definitions of PJK.
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Summary Of Background Data: Yilgor et al developed the lumbar Lordosis Distribution Index to individualize the pelvic mismatch to each patient's pelvic incidence. The cervical lordosis distribution in relation to its apex has not been characterized.

Objective: Tailor correction of cervical deformity by incorporating the cervical apex into a distribution index(CLDI) to maximize clinical outcomes while lowering rates of junctional failure.

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Background: Our understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch.

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Objective: Correction of mild flexible cervical deformity (CD) via the posterior approach has been described with and without the use of posterior osteotomies (POs), despite a lack of clarity regarding their necessity or risks. The purpose of this study was to determine whether the use of POs when correcting mild flexible CD leads to improved clinical or radiographic outcomes, as well as defining the relative risks in utilizing them.

Methods: A prospective multicenter registry of operative CD patients was analyzed.

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Purpose: To evaluate the variability in intraoperative fluid management during adult spinal deformity (ASD) surgery, and analyze the association with complications, intensive care unit (ICU) requirement, and length of hospital stay (LOS).

Methods: Multicenter comparative cohort study. Patients ≥ 18 years old and with ASD were included.

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Objective: This study aimed to assess whether elderly patients (aged ≥ 70 years) face an elevated risk of complications following pedicle subtraction osteotomy (PSO) for adult spinal deformity (ASD) compared with younger patients (< 70 years) and to evaluate if clinical and radiological outcomes differ between these age groups.

Methods: A retrospective analysis of 513 patients undergoing PSO for ASD by a single surgical team between January 2006 and January 2023 was conducted. Patients were categorized by age (≥ 70 years and < 70 years).

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Study Design: Retrospective Cohort Study.

Objectives: Length of Stay (LOS) and resource utilization are of primary importance for hospital administration. This study aimed to understand the incremental effect of having a specific complication on LOS among ASD patients.

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Background: Incongruity between irregularly shaped vertebral endplates and the uniform surfaces of stock interbody fusion cages has been identified as contributing to cage subsidence, pseudarthrosis, and unpredictable alignment. Advances in manufacturing techniques have driven the development of personalized interbody cages (PICs) that can match individual endplate morphology and provide the exact shape and size needed to fill the disc space and achieve the planned correction. This study used computed tomography (CT) imaging to evaluate the implant-endplate contact area, fusion, subsidence, and achievement of planned alignment correction in patients receiving PIC devices.

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Background: An abnormal postoperative lordosis distribution index (LDI), which quantifies the ratio between the lordosis at L4 to S1 and the lordosis at L1 to S1, contributes to the development of adjacent segment disease and increased revision rates in patients undergoing short-segment lumbar intervertebral fusions. Incorporating preoperative spinopelvic parameters and LDI into the surgical plan for short-segment fusion is important for guiding alignment restoration and preserving normal preoperative alignment in unfused segments. This study examined changes in LDI, segmental lordosis, and lordosis of the unfused levels in patients treated with personalized interbody cage (PIC) implants.

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Background: Lumbar lordosis distribution has become a pivotal factor in re-establishing the foundational alignment of the lumbar spine. This can directly influence overall sagittal alignment, leading to improved long-term outcomes for patients. Despite the wide availability of hyperlordotic stock cages intended to achieve optimal postoperative alignment, there is a lack of correlation between the lordotic shape of a cage and the resultant intervertebral alignment.

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Background: Literature supports the need for improved techniques to achieve spinopelvic alignment and reduce complication rates in patients with adult spinal deformity (ASD). Personalized interbody devices were developed to address this need and are under evaluation in the multicenter Clinical Outcome Measures in Personalized aprevo (circle R superscript) Spine Surgery (COMPASS (TM suprascript) registry. This report presents interim COMPASS pre- and postoperative sagittal alignment results and complication rates for a subcohort of COMPASS patients diagnosed and surgically treated for spinal deformity.

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Purpose: To assess the effect of various pelvic fixation techniques and number of rods on biomechanics of the proximal junction of long thoracolumbar posterior instrumented fusions.

Methods: A validated spinopelvic finite-element (FE) model was instrumented with L5-S1 ALIF and one of the following 9 posterior instrumentation configurations: (A) one traditional iliac screw bilaterally ("2 Iliac/2 Rods"); (B) T10 to S1 ("Sacral Only"); (C) unilateral traditional iliac screw ("1 Iliac/2 Rods"); (D) one traditional iliac screw bilaterally with one midline accessory rod ("2 Iliac/3 rods"); (E) S2AI screws connected directly to the midline rods ("2 S2AI/2 Rods"); and two traditional iliac screws bilaterally with two lateral accessory rods connected to the main rods at varying locations (F1: T10-11, F2: T11-12, F3: T12-L1, F4: L1-2) ("4 Iliac/4 Rods"). Range of motions (ROM) at T10-S1 and T9-T10 were recorded and compared between models.

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