Abstract Background Context Evaluation of sagittal alignment is essential in the operative treatment of spine pathology, particularly adult spinal deformity (ASD). However, software applications for ...detailed spino-pelvic analysis are usually complex and not applicable to routine clinical use. Purpose This study aimed to validate new clinician-friendly software (Surgimap) in the setting of ASD. Study Design/Setting Accuracy and inter- and intra-rater reliability of spine measurement software were tested. Five users (two experienced spine surgeons, three novice spine research fellows) independently performed each part of the study in two rounds with 1 week between measurements. Patient Sample Fifty ASD patients drawn from a prospective database were used as the study sample. Outcome Measures Spinal, pelvic, and cervical measurement parameters (including pelvic tilt PT, pelvic incidence PI, lumbar-pelvic mismatch PI-LL, lumbar lordosis LL, thoracic kyphosis TK, T1 spino-pelvic inclination T1SPI, sagittal vertical axis SVA, and cervical lordosis CL) were the outcome measures. Methods For the accuracy evaluation, 30 ASD patient radiographs were pre-marked for anatomic landmarks. Each radiograph was measured twice with the new software (Surgimap); measurements were compared to those from previously validated software. For the reliability and reproducibility evaluation, users measured 50 unmarked ASD radiographs in two rounds. Intra-class correlation (ICC) and International Organization for Standardization (ISO) reproducibility values were calculated. Measurement time was recorded. Results Surgimap demonstrated excellent accuracy as assessed by the mean absolute difference from validated measurements: PT: 0.12°, PI: 0.35°, LL: 0.58°, PI-LL: 0.46°, TK: 5.25°, T1SPI: 0.53°, and SVA: 2.04 mm. The inter- and intra-observer reliability analysis revealed good to excellent agreement for all parameters. The mean difference between rounds was <0.4° for PT, PI, LL, PI-LL, and T1SPI, and <0.3 mm for SVA. For PT, PI, LL, PI-LL, TK, T1SPI, and SVA, the intra-observer ICC values were all >0.93 and the inter-observer ICC values were all >0.87. Parameters based on point landmarks rather than end plate orientation had a better reliability (ICC≥0.95 vs. ICC≥0.84). The average time needed to perform a full spino-pelvic analysis with Surgimap was 75 seconds (+25). Conclusions Using this new software tool, a simple method for full spine analysis can be performed quickly, accurately, and reliably. The proposed list of parameters offers quantitative values of the spine and pelvis, setting the stage for proper preoperative planning. The new software tool provides an important bridge between clinical and research needs.
Current concepts review.
Outline the basic principles in the evaluation and treatment of adult spinal deformity patients with a focus on goals to achieve during surgical realignment surgery.
Proper ...global alignment of the spine is critical in maintaining standing posture and balance in an efficient and pain-free manner. Outcomes data demonstrate the clinical effect of spinopelvic malalignment and form a basis for realignment strategies.
Correlation between certain radiographic parameters and patient self-reported pain and disability has been established. Using normative values for several important spinopelvic parameters (including sagittal vertical axis, pelvic tilt, and lumbar lordosis), spinopelvic radiographic realignment objectives were identified as a tool for clinical application. Because of the complex relationship between the spine and the pelvis in maintaining posture and the wide range of "normal" values for the associated parameters, a focus on global alignment, with proportionality of individual parameters to each other, was pursued to provide clinical relevance to planning realignment for deformity across a range of clinical cases.
Good clinical outcome requires achieving proper spinopelvic alignment in the treatment of adult spinal deformity. Although variations in pelvic morphology exist, a framework has been established to determine ideal values for regional and global parameter in an individualized patient approach. When planning realignment surgery for adult spinal deformity, restoring low sagittal vertical axis and pelvic tilt values are critical goals, and should be combined with proportional lumbar lordosis to pelvic incidence.
Research update, focused review.
Identify the role of the pelvis in the setting of adults with spinal deformity.
Sagittal plane alignment is increasingly recognized as a critical parameter in the ...setting of adult spinal deformity. Additionally, pelvic parameters reveal to be a key component in the regulation of sagittal alignment.
Analysis of the pelvis in the sagittal plane is commonly assessed by 3 angular measurements: the pelvic incidence (morphologic parameter directly linked to sagittal morphotypes), the pelvic tilt (or pelvis retroversion used to maintain an upright posture in the setting of spinal deformity), and the sacral slope. Recent work using force plate technology has revealed that in the setting of anterior trunk inclination ("spinal imbalance"), the pelvis shifted posteriorly (toward the heels) in order to maintain a balanced mass distribution. The complex relationship between pelvic and spinal parameter were investigated in order to construct predictive formulas of postoperative spinopelvic alignment. It has emerged that pelvic tilt is highly correlated with patient self reported function (ODI, SF-12, and SRS).
It has become evident that good clinical outcome in the treatment of spinal deformity requires proper alignment. Pelvis parameters play an essential role not only in terms of spine morphotypes but also in regulating standing balance and postoperative alignment. Thus, optimal treatment of a patient with spinal deformity requires integration of the pelvis in the preoperative evaluation and treatment plan.
Inter- and intra-rater variability study.
On the basis of a Scoliosis Research Society effort, this study seeks to determine whether the new adult spinal deformity (ASD) classification system is ...clear and reliable.
A classification of adult ASD can serve several purposes, including consistent characterization of a clinical entity, a basis for comparing different treatments, and recommended treatments. Although pediatric scoliosis classifications are well established, an ASD classification is still being developed. A previous classification developed by Schwab et al has met with clinical relevance but did not include pelvic parameters, which have shown substantial correlation with health-related quality of life measures in recent studies.
Initiated by the Scoliosis Research Society Adult Deformity Committee, this study revised a previously published classification to include pelvic parameters. Modifier cutoffs were determined using health-related quality of life analysis from a multicenter database of adult deformity patients. Nine readers graded 21 premarked cases twice each, approximately 1 week apart. Inter- and intra-rater variability and agreement were determined for curve type and each modifier separately. Fleiss' kappa was used for reliability measures, with values of 0.00 to 0.20 considered slight, 0.21 to 0.40 fair, 0.41 to 0.60 moderate, 0.61 to 0.80 substantial, and 0.81 to 1.00 almost perfect agreement.
Inter-rater kappa for curve type was 0.80 and 0.87 for the 2 readings, respectively, with modifier kappas of 0.75 and 0.86, 0.97 and 0.98, and 0.96 and 0.96 for pelvic incidence minus lumbar lordosis (PI-LL), pelvic tilt (PT), and sagittal vertical axis (SVA), respectively. By the second reading, curve type was identified by all readers consistently in 66.7%, PI-LL in 71.4%, PT in 95.2%, and SVA in 90.5% of cases. Intra-rater kappa averaged 0.94 for curve type, 0.88 for PI-LL, 0.97 for PT, and 0.97 for SVA across all readers.
Data from this study show that there is excellent inter- and intra-rater reliability and inter-rater agreement for curve type and each modifier. The high degree of reliability demonstrates that applying the classification system is easy and consistent.
Abstract Background context Spine surgery is usually associated with large amount of blood loss, necessitating blood transfusions. Blood loss-associated morbidity can be because of direct risks, such ...as hypotension and organ damage, or as a result of blood transfusions. The antifibrinolytic, tranexamic acid (TXA), is a lysine analog that inhibits activation of plasminogen and has shown to be beneficial in reducing surgical blood loss. Purpose To consolidate the findings of randomized controlled trials (RCTs) investigating the use of TXA on surgical bleeding in spine surgery. Study design A metaanalysis. Study sample Randomized controlled trials investigating the effectiveness of intravenous TXA in reducing blood loss in spine surgery, compared with a placebo/no treatment group. Methods MEDLINE, Embase, Cochrane controlled trials register, and Google Scholar were used to identify RCTs published before January 2014 that examined the effectiveness of intravenous TXA on reduction of blood loss and blood transfusions, compared with a placebo/no treatment group in spine surgery. Metaanalysis was performed using RevMan 5. Weighted mean difference with 95% confidence intervals was used to summarize the findings across the trials for continuous outcomes. Dichotomous data were expressed as risk ratios with 95% confidence intervals. A p<.05 was considered statistically significant. Results Eleven RCTs were included for TXA (644 total patients). Tranexamic acid reduced intraoperative, postoperative, and total blood loss by an average of 219 mL (−322, −116, p<.05), 119 mL (−141, −98, p<.05), and 202 mL (−299, −105, p<.05), respectively. Tranexamic acid led to a reduction in proportion of patients who received a blood transfusion (risk ratio 0.67 0.54, 0.83, p<.05) relative to placebo. There was one myocardial infarction (MI) in the TXA group and one deep vein thrombosis (DVT) in placebo. Conclusions Tranexamic acid reduces surgical bleeding and transfusion requirements in patients undergoing spine surgery. Tranexamic acid does not appear to be associated with an increased incidence of pulmonary embolism, DVT, or MI.
Highlights • Sagittal analysis of the spine is not a deformity specific exercise. • Pelvic morphology is the foundation for spinal alignment. • SRS-Schwab sagittal modifiers are established targets ...for spinal realignment. • Realignment procedures should respect age-adjusted alignment targets.
Background Hip osteoarthritis often coexists with adult spinal deformity, an abnormality in which sagittal spinopelvic malalignment is present. Debate exists whether to perform spinal realignment ...correction or total hip arthroplasty first. Hip extension and pelvic tilt are important compensatory mechanisms in the setting of sagittal spinopelvic malalignment and change after spinal realignment. We performed this study to evaluate the effect that the spinal realignment surgical procedure has on acetabular anteversion. Methods This study is a retrospective review of a multicenter, prospective, consecutive database of patients with adult spinal deformity who underwent surgical spinal realignment. Only patients who already had undergone a total hip arthroplasty prior to the spinal realignment procedure were retained for analysis. Patients were excluded if they had insufficient imaging or large-head, metal-on-metal bearings or they had undergone revision total hip arthroplasty in the study period. Acetabular anteversion was calculated via the ellipse method on a standing, posterior-anterior, 90-cm radiograph with a well-centered pelvis. Anteversion was measured preoperatively and at six weeks or three months after the spinal realignment procedure. Spinopelvic parameters measured included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, T 0005 pelvic angle, sagittal vertical axis, T1-spinopelvic inclination, and thoracic kyphosis. Results Forty-one hips (thirty-three patients) were identified. Acetabular anteversion significantly reduced (p < 0.001) after spinal correction by mean change of −4.96° (range, −22.32° to +2.36°). The change in anteversion correlated with the changes in sagittal pelvic orientation (0.828 for the pelvic tilt, −0.757 for the sacral slope, and −0.691 for the lumbar lordosis) and global spinopelvic alignment (0.579 for the sagittal vertical axis and 0.585 for the T 0005 pelvic angle). Regression analysis revealed that anteversion decreased by 1° for each of the following spinopelvic parameter changes (p < 0.001): 1.105° for spinopelvic tilt, 1.032° for sacral slope, and 3.163° for lumbar lordosis. Conclusions Patients with spinopelvic malalignment had a high prevalence of excessively anteverted acetabular components. Sagittal spinal correction following total hip arthroplasty resulted in reduced acetabular anteversion, which may have implications for stability. Changes in anteversion are most closely related to changes in pelvic tilt in an almost one-to-one ratio. Level of Evidence Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.
Purpose
To compare topical tranexamic acid versus intravenous tranexamic acid in reducing intra- and postoperative blood loss and transfusion rate in deformity patients.
Materials and method
We ...performed a retrospective cohort study with posterior fusion deformity patients, between 2009 and 2016. Patients were categorized in 4 groups: “No TXA” (
n
= 35) if the wound was packed with saline soaked sponges, “IV TXA” (
n
= 37) the patient received 20 mg/kg bolus at the beginning of the surgery followed by continuous infusion of 1 mg/kg/hr until closure, “Topical TXA” (
n
= 23) the wound was packed with sponges soaked in 6 g of TXA diluted in a 3 L saline solution, or “Combined TXA” (
n
= 86) the patient received both IV and topical TXA. The primary outcomes were total, intra- and postoperative blood loss, surgical time, postoperative Ht/Hb, transfusion rates, and duration of drain insertion.
Results
A total of 181 patients were analyzed (78.6%
F
, 15.08 yo). No differences were found in total and intraoperative blood loss, surgical time, postoperative Ht/Ht, and transfusion rates. “Combined TXA” group had significantly less postoperative bleeding than “no TXA” group (
p
= 0.022). IV TXA patients (with o/without topical TXA) removed drains one day earlier than the no TXA group (
p
= 0.002). There were no complications related to the use of tranexamic acid.
Conclusion
There is significant decrease in postoperative bleeding in pediatric deformity patients with combined topical and IV tranexamic acid.
Abstract
BACKGROUND:
Global sagittal malalignment is significantly correlated with health-related quality-of-life scores in the setting of spinal deformity. In order to address rigid deformity ...patterns, the use of spinal osteotomies has seen a substantial increase. Unfortunately, variations of established techniques and hybrid combinations of osteotomies have made comparisons of outcomes difficult.
OBJECTIVE:
To propose a classification system of anatomically-based spinal osteotomies and provide a common language among spine specialists.
METHODS:
The proposed classification system is based on 6 anatomic grades of resection (1 through 6) corresponding to the extent of bone resection and increasing degree of destabilizing potential. In addition, a surgical approach modifier is added (posterior approach or combined anterior and posterior approaches). Reliability of the classification system was evaluated by an analysis of 16 clinical cases, rated 2 times by 8 different readers, and calculation of Fleiss kappa coefficients.
RESULTS:
Intraobserver reliability was classified as “almost perfect”; Fleiss kappa coefficient averaged 0.96 (range, 0.92-1.0) for resection type and 0.90 (0.71-1.0) for the approach modifier. Results from the interobserver reliability for the classification were 0.96 for resection type and 0.88 for the approach modifier.
CONCLUSION:
This proposed anatomically based classification system provides a consistent description of the various osteotomies performed in spinal deformity correction surgery. The reliability study confirmed that the classification is simple and consistent. Further development of its use will provide a common frame for osteotomy assessment and permit comparative analysis of different treatments.
Abstract
BACKGROUND:
Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion.
OBJECTIVE:
To evaluate the ...relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion.
METHODS:
From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-related quality-of-life scores.
RESULTS:
Both C2-C7 SVA and CGH-C7 SVA negatively correlated with SF-36 physical component scores (r = −0.43, P < .001 and r = −0.36, P = .005, respectively). C2-C7 SVA positively correlated with NDI scores (r = 0.20, P = .036). C2-C7 SVA positively correlated with C1-C2 lordosis (r = 0.33, P = .001). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of approximately 40 mm, beyond which correlations were most significant.
CONCLUSION:
Our findings demonstrate that, similar to the thoracolumbar spine, the severity of disability increases with positive sagittal malalignment following surgical reconstruction.
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