Abstract
BackgroundCurrently, the trajectory for insertion of an external ventricular drain (EVD) is mainly determined using anatomical landmarks. However, non-assisted implantations frequently require multiple attempts and are associated with EVD malpositioning and complications. The authors evaluated the feasibility and accuracy of a novel smartphone-guided, angle-adjusted technique for assisted implantations of an EVD (sEVD) in both a human artificial head model and a cadaveric head.MethodsAfter computed tomography (CT), optimal insertion angles and lengths of intracranial trajectories of the EVDs were determined. A smartphone was calibrated to the mid-cranial sagittal line. Twenty EVDs were placed using both the premeasured data and smartphone-adjusted insertion angles, targeting the center of the ipsilateral ventricular frontal horn. The EVD positions were verified with post-interventional CT.ResultsAll 20 sEVDs (head model, 8/20; cadaveric head, 12/20) showed accurate placement in the ipsilateral ventricle. The sEVD tip locations showed a mean target deviation of 1.73° corresponding to 12 mm in the plastic head model, and 3.45° corresponding to 33 mm in the cadaveric head. The mean duration of preoperative measurements on CT data was 3 min, whereas sterile packing, smartphone calibration, drilling, and implantation required 9 min on average.ConclusionsBy implementation of an innovative navigation technique, a conventional smartphone was used as a protractor for the insertion of EVDs. Our ex vivo data suggest that smartphone-guided EVD placement offers a precise, rapidly applicable, and patient-individualized freehand technique based on a standard procedure with a simple, cheap, and widely available multifunctional device.
Highlights
Insertion of an external ventricular drain (EVD) is one of the most commonly performed procedures in daily neurosurgical practice [6, 7]
Neurosurgeons prefer methods that are quick and easy to use and barely differ from established clinical routine [24]. Taking these considerations into account and encouraged by results from an iPod-based navigation procedure described previously [11, 18], we developed a novel smartphone-guided, angle-adjusted technique for implantation of an EVD
The optimal lateral pre-insertional angles planned in the coronal plane averaged 10.54° (SD ± 5.37, range 4° to 19.6°), whereas the average angles measured on post-interventional computed tomography (CT) imaging were 11.34° (SD ± 4.34, range 0.69° to 19.4°)
Summary
Insertion of an external ventricular drain (EVD) is one of the most commonly performed procedures in daily neurosurgical practice [6, 7]. The standard technique is still the traditional non-navigation-assisted freehand placement exclusively guided by anatomical landmarks [2, 7, 28]. By this method, an EVD is usually inserted at Kocher’s point [9] and directed towards the nasion in the sagittal plane, and the tragus or slightly anterior in the coronal plane [13, 23]. The trajectory for insertion of an external ventricular drain (EVD) is mainly determined using anatomical landmarks. The authors evaluated the feasibility and accuracy of a novel smartphone-guided, angleadjusted technique for assisted implantations of an EVD (sEVD) in both a human artificial head model and a cadaveric head
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