Dataset Information

Quantification of computational geometric congruence in surface-based registration for spinal intra-operative three-dimensional navigation.

ABSTRACT:

Background context

Computer-assisted navigation (CAN) may guide spinal instrumentation, and requires alignment of patient anatomy to imaging. Iterative closest-point (ICP) algorithms register anatomical and imaging surface datasets, which may fail in the presence of geometric symmetry (congruence), leading to failed registration or inaccurate navigation. Here we computationally quantify geometric congruence in posterior spinal exposures, and identify predictors of potential navigation inaccuracy.

Methods

Midline posterior exposures were performed from C1-S1 in four human cadavers. An optically-based CAN generated surface maps of the posterior elements at each level. Maps were reconstructed to include bilateral hemilamina, or unilateral hemilamina with/without the base of the spinous process. Maps were fitted to symmetrical geometries (cylindrical/spherical/planar) using computational modelling, and the degree of model fit quantified based on the ratio of model inliers to total points. Geometric congruence was subsequently assessed clinically in 11 patients undergoing midline exposures in the cervical/thoracic/lumbar spine for posterior instrumented fusion.

Results

In cadaveric testing, increased cylindrical/spherical/planar symmetry was seen in the high-cervical and subaxial cervical spine relative to the thoracolumbar spine (p<0.001). Extension of unilateral exposures to include the ipsilateral base of the spinous process decreased symmetry independent of spinal level (p<0.001). In clinical testing, increased cylindrical/spherical/planar symmetry was seen in the subaxial cervical relative to the thoracolumbar spine (p<0.001), and in the thoracic relative to the lumbar spine (p<0.001). Symmetry in unilateral exposures was decreased by 20% with inclusion of the ipsilateral base of the spinous process.

Conclusions

Geometric congruence is most evident at C1 and the subaxial cervical spine, warranting greater vigilance in navigation accuracy verification. At all levels, inclusion of the base of the spinous process in unilateral registration decreases the likelihood of geometric symmetry and navigation error. This work is important to allow the extension of line-of-sight based registration techniques to minimally-invasive unilateral approaches.

SUBMITTER: Guha D

PROVIDER: S-EPMC6710030 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Quantification of computational geometric congruence in surface-based registration for spinal intra-operative three-dimensional navigation.

Guha Daipayan D Jakubovic Raphael R Leung Michael K MK Ginsberg Howard J HJ Fehlings Michael G MG Mainprize Todd G TG Yee Albert A Yang Victor X D VXD

PloS one 20190826 8

<h4>Background context</h4>Computer-assisted navigation (CAN) may guide spinal instrumentation, and requires alignment of patient anatomy to imaging. Iterative closest-point (ICP) algorithms register anatomical and imaging surface datasets, which may fail in the presence of geometric symmetry (congruence), leading to failed registration or inaccurate navigation. Here we computationally quantify geometric congruence in posterior spinal exposures, and identify predictors of potential navigation in ...[more]

PMID: 31450234

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Project description:BackgroundVenous thromboembolism (VTE) is the most common preventable cause of 30-day post-operative mortality, with many events occurring after hospital discharge. High-level evidence supports post-discharge VTE chemoprophylaxis following abdominal/pelvic cancer resection; however, some studies support a more tailored approach. Our objectives were to (1) identify risk factors associated with post-discharge VTE in a large cohort of patients undergoing colorectal cancer resection and (2) develop a post-discharge VTE risk calculator.MethodsPatients who underwent colorectal cancer resection from 2012 to 2016 were identified from ACS NSQIP colectomy and proctectomy procedure-targeted modules. Multivariable logistic regression was used to identify factors associated with post-discharge VTE. Incorporating pre-operative, intra-operative, and post-operative variables, a post-discharge VTE risk calculator was constructed and validated.ResultsOf 51,139 patients, 387 (0.76%) developed post-discharge VTE. Pre-operative factors associated with post-discharge VTE included BMI (e.g., morbidly obese OR 2.27, 95% CI 1.65-3.12 vs. normal BMI), and thrombocytosis (OR 1.41, 95% CI 1.03-1.92). Intra-operative factors included operative time (4-6 h OR 1.56, 95% CI 1.12-2.17; > 6 h, OR 1.85, 95% CI 1.21-2.84, vs. < 2 h), and type of operation (e.g., open partial colectomy OR 1.67, 95% CI 1.30-2.16 vs. laparoscopic partial colectomy). Post-operative factors included anastomotic leak (OR 2.05, 95% CI 1.31-3.21) and post-operative ileus (OR 1.39, 95% CI 1.07-1.79). Using the risk calculator, the predicted probability of post-discharge VTE ranged from 0.04 to 10.29%. On a 10-fold cross validation, the calculator's mean C-Statistic was 0.65.ConclusionsPatient-specific factors are associated with varying rates of post-discharge VTE. We present the first post-discharge VTE risk calculator designed for use at the time of discharge following colorectal cancer resection.

Dataset Information

Quantification of computational geometric congruence in surface-based registration for spinal intra-operative three-dimensional navigation.

Background context

Methods

Results

Conclusions

Publications

Quantification of computational geometric congruence in surface-based registration for spinal intra-operative three-dimensional navigation.

Similar Datasets

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