Localization of brain tumors with a simple scalp-mounted fiducial device. Technical note

Use of Marker Computed Tomography as a Navigational Tool for Performing Minicraniotomies

We want to highlight a simple technique for performing smaller craniotomies, using a marker computed tomography scan, which does not require any special equipment, training or cost and is not time-consuming. Pictorial description of two such cases have been provided.

Minimally invasive supratentorial neurosurgical approaches guided by Smartphone app and compass

The precise location in the scalp of specifically planned points can help to achieve less invasive approaches. This study aims to develop a smartphone app, evaluate the precision and accuracy of the developed tool, and describe a series of cases using the referred technique. The application was developed with the React Native framework for Android and iOS. A phantom was printed based on the patient's CT scan, which was used for the calculation of accuracy and precision of the method. The points of interest were marked with an "x" on the patient's head, with the aid of the app and a compass attached to a skin marker pen. Then, two experienced neurosurgeons checked the plausibility of the demarcations based on the anatomical references. Both evaluators marked the frontal, temporal and parietal targets with a difference of less than 5 mm from the corresponding intended point, in all cases. The overall average accuracy observed was 1.6 ± 1.0 mm. The app was used in the surgical planning of trepanations for ventriculoperitoneal (VP) shunts and for drainage of abscesses, and in the definition of craniotomies for meningiomas, gliomas, brain metastases, intracranial hematomas, cavernomas, and arteriovenous malformation. The sample consisted of 88 volunteers who exhibited the following pathologies: 41 (46.6%) had brain tumors, 17 (19.3%) had traumatic brain injuries, 16 (18.2%) had spontaneous intracerebral hemorrhages, 2 (2.3%) had cavernomas, 1 (1.1%) had arteriovenous malformation (AVM), 4 (4.5%) had brain abscesses, and 7 (7.9%) had a VP shunt placement. In cases approached by craniotomy, with the exception of AVM, straight incisions and minicraniotomy were performed. Surgical planning with the aid of the NeuroKeypoint app is feasible and reliable. It has enabled neurological surgeries by craniotomy and trepanation in an accurate, precise, and less invasive manner.

HeaDax: A simple pre-surgical procedure for localizing superficial brain lesions in resource-limited environments

Background:

Intracranial convexity lesions are poorly defined by recognizable anatomical landmarks. Even in expert hands, exact localization of small subcortical lesion and its projection to the skull is sometimes unreliable and can cause potential surgical complications. In this report, a simple and handy technique for localizing superficial intracranial lesions on the scalp under computed tomography (CT)-scan guidance is described.

Methods:

This technique, HeaDax, is based on using extracranial landmarks. We constructed an isosceles square triangle with three pieces of copper electrical wire and placed it on the skin scalp. Then, we took a CT-scan but without the need of the classic head reference planes (e.g., orbitomeatal or along the orbital roof).

Results:

For the measurements, we need to have the intracranial lesion located on the CT slice with respect to the two landmarks which are the height and hypotenuse of the triangle. The promising preliminary results of HeaDax applied to a phantom skull model encourage us to use it successfully for our first patient presenting a right subcortial supramarginal retrorolandic cavernoma.

Conclusion:

HeaDax procedure is a good alternative for localizing superficial intracranial lesions on the skin scalp under CT-scan or magnetic resonance imaging guidance. It can be used as a substitute when stereotactic and neuronavigation systems are not easily available, especially in developing countries and in resource-limited environments. HeaDax has a true potential for further developments and applications in cranial surgery.

Proiezione extracranica di lesioni all'interno del cranio

Descrizione di una tecnica TC che consente di proiettare fuori dal cranio una lesione contenuta al suo interno e poi disegnarla sulla cute del paziente. La tecnica ci sembra utile in Neurochirurgia per favorire il raggiungimento di una lesione in corso di intervento e in radioterapia esterna o interstiziale, con infissione intratumorale di isotopi radioattivi. Viene riportato un caso clinico in cui la tecnica ha fornito la spiegazione del mancato rinvenimento di un tumore all'intervento chirurgico.

A new model for non-invasive, reproducible fixation of a stereotaxic frame using an orthodontic resin plate. Technical note

The authors describe a new method for reproducible, non-invasive fixation of a stereotaxic localizing frame. A localizing system similar to that of Brown-Roberts-Wells for MR can be fixed at the base of the facial skeleton to the upper dental arch by an orthodontic resin plate. Results of trials with CT scan, advantages and disadvantages are discussed. The new fixture could be employed in open surgery and in fractionated radiotherapy.

Direct skull marking for a pre-operative localization in regional cerebral surgery. Technical note

A method is described in which an open neurosurgical target is pre-operatively marked on the skull of a patient. A target point of the scalp surface localized from neuroimaging studies is transferred onto the skull by an injection of pyoktanin blue. Its accuracy and reliability is far superior than that of the usual scalp marking. The method is simple, practical, and allows a smaller, regional craniotomy with the advantage of minimum operative invasiveness.

Stereotactic craniotomy and intraoperative lesion localisation using the Brown-Robert-Wells frame. Technical note

A simple technique of stereotactic craniotomy and intraoperative lesion localisation that uses the Brown-Robert-Wells (BRW) stereotactic frame is presented. The method optimises craniotomy placement and facilitates localisation of small intracerebral lesions. Using the system, 16 patients have had resection of intracranial neoplasms from deep and/or eloquent areas of the brain with no neurological morbidity.