Improving Successful Cannulation of External Ventricular Drain: 3D Printed Surgical Guide for Inexperienced Neurosurgeons.

OBJECTIVE: External Ventricular Drain (EVD) is a fundamental neurosurgical procedure that is commonly performed by junior neurosurgeons. Expedient, successful cannulation of the ventricles can be lifesaving. Yet, the free-hand technique of EVD insertion is associated with significant mal-positioning rates. This study aims to improve EVD placement by junior neurosurgeons with the aid of a customized 3D printed surgical guide. METHODS: A 3D printed surgical guide was developed and customized to our institution's EVD insertion procedure. First year neurosurgical residents were taught how to perform pre-operative trajectory planning based on coronal brain images and how to use the surgical guide during standard EVD insertion procedure. Number of passes, accuracy of EVD placement, operative complications, need for revision, and surgeon's experience with the guide were recorded. RESULTS: 14 patients underwent guide-assisted EVD insertion by first year neurosurgical residents. Significantly, 6 (43%) patients had ventricular anatomy distorted by midline shift. All surgeons achieved successful ventricular cannulation using the EVD guide on first pass (100%). 13 out of 14 (93%) of the guide-assisted EVDs were optimally placed (Karkarla Grade 1). 1 (7%) guide-assisted EVD was suboptimally placed (Karkarla Grade 2). There was no intra or post-operative complication and there was no EVD revision. CONCLUSIONS: For inexperienced surgeons, the 3D printed EVD guide can improve ventricular cannulation even in cases of altered ventricular anatomy. The benefit of 3D printing would also allow the guide to be widely adopted by other institutions worldwide.

Forebrain medial septum sustains experimental neuropathic pain.

The present study explored the role of the medial septal region (MS) in experimental neuropathic pain. For the first time, we found that the MS sustains nociceptive behaviors in rodent models of neuropathic pain, especially in the chronic constriction injury (CCI) model and the paclitaxel model of chemotherapy-induced neuropathic pain. For example, inactivation of the MS with intraseptal muscimol (2 µg/µl, 0.5 µl), a GABA mimetic, reversed peripheral hypersensitivity (PH) in the CCI model and induced place preference in a conditioned place preference task, a surrogate measure of spontaneous nociception. The effect of intraseptal muscimol on PH was comparable to that seen with microinjection of the local anesthetic, lidocaine, into rostral ventromedial medulla which is implicated in facilitating experimental chronic nociception. Cellular analysis in the CCI model showed that the MS region sustains nociceptive gain with CCI by facilitating basal nociceptive processing and the amplification of stimulus-evoked neural processing. Indeed, consistent with the idea that excitatory transmission through MS facilitates chronic experimental pain, intraseptal microinjection of antagonists acting at AMPA and NMDA glutamate receptors attenuated CCI-induced PH. We propose that the MS is a central monitor of bodily nociception which sustains molecular plasticity triggered by persistent noxious insult.