Dataset Information

Quantitative Assessment of Orbital Implant Position--A Proof of Concept.

ABSTRACT:

Introduction

In orbital reconstruction, the optimal location of a predefined implant can be planned preoperatively. Surgical results can be assessed intraoperatively or postoperatively. A novel method for quantifying orbital implant position is introduced. The method measures predictability of implant placement: transformation parameters between planned and resulting implant position are quantified.

Methods

The method was tested on 3 human specimen heads. Computed Tomography scans were acquired at baseline with intact orbits (t0), after creation of the defect (t1) and postoperatively after reconstruction of the defect using a preformed implant (t2). Prior to reconstruction, the optimal implant position was planned on the t0 and t1 scans. Postoperatively, the planned and realized implant position were compared. The t0 and t2 scans were fused using iPlan software and the resulting implant was segmented in the fused t2 scan. An implant reference frame was created (Orbital Implant Positioning Frame); the planned implant was transformed to the reference position using an Iterative Closest Point approach. The segmentation of the resulting implant was also registered on the reference position, yielding rotational (pitch, yaw, roll) as well as translational parameters of implant position.

Results

Measurement with the Orbital Implant Positioning Frame proved feasible on all three specimen. The positional outcome provided more thorough and accurate insight in resulting implant position than could be gathered from distance measurements alone. Observer-related errors were abolished from the process, since the method is largely automatic.

Conclusion

A novel method of quantifying surgical outcome in orbital reconstructive surgery was presented. The presented Orbital Implant Positioning Frame assessed all parameters involved in implant displacement. The method proved to be viable on three human specimen heads. Clinically, the method could provide direct feedback intraoperatively and could improve postoperative evaluation of orbital reconstructive surgery.

SUBMITTER: Schreurs R

PROVIDER: S-EPMC4777501 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

Quantitative Assessment of Orbital Implant Position--A Proof of Concept.

Schreurs Ruud R Dubois Leander L Becking Alfred G AG Maal Thomas J J TJ

PloS one 20160303 3

<h4>Introduction</h4>In orbital reconstruction, the optimal location of a predefined implant can be planned preoperatively. Surgical results can be assessed intraoperatively or postoperatively. A novel method for quantifying orbital implant position is introduced. The method measures predictability of implant placement: transformation parameters between planned and resulting implant position are quantified.<h4>Methods</h4>The method was tested on 3 human specimen heads. Computed Tomography scans ...[more]

PMID: 26939123

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Project description:Background and aimsIntracranial compliance refers to the relationship between a change in intracranial volume and the resultant change in intracranial pressure (ICP). Measurement of compliance is useful in managing cardiovascular and respiratory failure; however, there are no contemporary means to assess intracranial compliance. Knowledge of intracranial compliance could complement ICP and cerebral perfusion pressure (CPP) monitoring in patients with severe traumatic brain injury (TBI) and may enable a proactive approach to ICP management. In this proof-of-concept study, we aimed to capitalize on the physiologic principles of intracranial compliance and vascular reactivity to CO2, and standard-of-care neurocritical care monitoring, to develop a method to assess dynamic intracranial compliance.MethodsContinuous ICP and end-tidal CO2 (ETCO2) data from children with severe TBI were collected after obtaining informed consent in this Institutional Review Board-approved study. An intracranial pressure-PCO2 Compliance Index (PCI) was derived by calculating the moment-to-moment correlation between change in ICP and change in ETCO2. As such, "good" compliance may be reflected by a lack of correlation between time-synched changes in ICP in response to changes in ETCO2, and "poor" compliance may be reflected by a positive correlation between changes in ICP in response to changes in ETCO2.ResultsA total of 978 h of ICP and ETCO2 data were collected and analyzed from eight patients with severe TBI. Demographic and clinical characteristics included patient age 7.1?±?5.8 years (mean?±?SD); 6/8 male; initial Glasgow Coma Scale score 3 [3-7] (median [IQR]); 6/8 had decompressive surgery; 7.1?±?1.4 ICP monitor days; ICU length of stay (LOS) 16.1?±?6.8 days; hospital LOS 25.9?±?8.4 days; and survival 100%. The mean PCI for all patients throughout the monitoring period was 0.18?±?0.04, where mean ICP was 13.7?±?2.1 mmHg. In this cohort, PCI was observed to be consistently above 0.18 by 12 h after monitor placement. Percent time spent with PCI thresholds?>?0.1, 0.2, and 0.3 were 62% [24], 38% [14], and 23% [15], respectively. The percentage of time spent with an ICP threshold?>?20 mmHg was 5.1% [14.6].ConclusionsIndirect assessment of dynamic intracranial compliance in TBI patients using standard-of-care monitoring appears feasible and suggests a prolonged period of derangement out to 5 days post-injury. Further study is ongoing to determine if the PCI-a new physiologic index, complements utility of ICP and/or CPP in guiding management of patients with severe TBI.

Dataset Information

Quantitative Assessment of Orbital Implant Position--A Proof of Concept.

Introduction

Methods

Results

Conclusion

Publications

Quantitative Assessment of Orbital Implant Position--A Proof of Concept.

Similar Datasets

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