Surgical simulation of cerebral revascularization via skull base approaches in the posterior circulation using three-dimensional skull model with artificial brain and blood vessels

Neurosurgical Microvascular Anastomosis: Systematic Review of the Existing Simulators and Proposal of a New Training Classification System

BACKGROUND

The literature lacks a combined analysis of neurosurgical microvascular anastomosis training models. We performed a systematic literature search to provide an overview of the existing models and proposed a classification system based on the level of simulation and reproducibility of the microvascular anastomosis.

METHODS

The systematic literature search followed the PRISMA guidelines. We consulted MEDLINE, Web of Knowledge, and EMBASE independently for papers about bypass training models. Every training model was analyzed according to six tasks supposed to esteem their fidelity to the real operative setting by using a scoring system from zero to two. Finally, authors classified the models into five classes, from A to E, by summing the individual scores.

RESULTS

This study included 109 papers for analysis. Training models were grouped into synthetic tubes, ex vivo models (animal vessels, fresh human cadavers, human placentas) and in vivo simulators (live animals-rats, rabbits, pigs). By applying the proposed classification system, live animals and placentas obtained the highest scores, falling into class A (excellent simulators). Human cadavers and animal vessels (ex vivo) were categorized in class B (good simulators), followed by synthetic tubes (class C, reasonable simulators).

CONCLUSIONS

The proposed classification system helps the neurosurgeon to analyze the available training models for microvascular anastomosis critically, and to choose the most appropriate one according to the skills they need to improve.

A novel, reusable, realistic neurosurgical training simulator for cerebrovascular bypass surgery: Iatrotek® bypass simulator validation study and literature review

Background

Microanastomosis is a challenging technique requiring continuous training to be mastered. Several models have been proposed, but few effectively reflect a real bypass surgery; even fewer are reusable, most are not easily accessible, and the setting is often quite long. We aim to validate a simplified, ready-to-use, reusable, ergonomic bypass simulator.

Methods

Twelve novice and two expert neurosurgeons completed eight End-to-End (EE), eight End-to-Side (ES), and eight Side-to-Side (SS) microanastomoses using 2-mm synthetic vessels. Data on time to perform bypass (TPB), number of sutures and time required to stop potential leaks were collected. After the last training, participants completed a Likert Like Survey for bypass simulator evaluation. Each participant was assessed using the Northwestern Objective Microanastomosis Assessment Tool (NOMAT).

Results

When comparing the first and last attempts, an improvement of the mean TPB was registered in both groups for the three types of microanastomosis. The improvement was always statistically significant in the novice group, while in the expert group, it was only significant for ES bypass. The NOMAT score improved in both groups, displaying statistical significance in the novices for EE bypass. The mean number of leakages, and the relative time for their resolution, also tended to progressively reduce in both groups by increasing the attempts. The Likert score expressed by the experts was slightly higher (25 vs. 24.58 by the novices).

Conclusions

Our proposed bypass training model may represent a simplified, ready-to-use, reusable, ergonomic, and efficient system to improve eye-hand coordination and dexterity in performing microanastomoses.

3D printed bone models in oral and cranio-maxillofacial surgery: a systematic review

AIM

This systematic review aimed to evaluate the use of three-dimensional (3D) printed bone models for training, simulating and/or planning interventions in oral and cranio-maxillofacial surgery.

MATERIALS AND METHODS

A systematic search was conducted using PubMed® and SCOPUS® databases, up to March 10, 2019, by following the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol. Study selection, quality assessment (modified Critical Appraisal Skills Program tool) and data extraction were performed by two independent reviewers. All original full papers written in English/French/Italian and dealing with the fabrication of 3D printed models of head bone structures, designed from 3D radiological data were included. Multiple parameters and data were investigated, such as author's purpose, data acquisition systems, printing technologies and materials, accuracy, haptic feedback, variations in treatment time, differences in clinical outcomes, costs, production time and cost-effectiveness.

RESULTS

Among the 1157 retrieved abstracts, only 69 met the inclusion criteria. 3D printed bone models were mainly used as training or simulation models for tumor removal, or bone reconstruction. Material jetting printers showed best performance but the highest cost. Stereolithographic, laser sintering and binder jetting printers allowed to create accurate models with adequate haptic feedback. The cheap fused deposition modeling printers exhibited satisfactory results for creating training models.

CONCLUSION

Patient-specific 3D printed models are known to be useful surgical and educational tools. Faced with the large diversity of software, printing technologies and materials, the clinical team should invest in a 3D printer specifically adapted to the final application.

Minimum Transpetrosal Retrolabyrinthine Approach for Revascularization of Posterior Cerebral Artery: Operative Nuance

BACKGROUND

Revascularization of the posterior cerebral artery (PCA) can be essential for treating complex cerebral aneurysms in the posterior circulation, and it is considered technically challenging. To help decrease the difficulty of this technique, we developed the minimum transpetrosal approach (MTPA).

OBJECTIVE

The technical nuances of the MTPA were innovated by cadaver head dissections and an actual clinical case.

METHODS

Four sides of the formalin-fixed cadaver heads were used to investigate if the posterior cerebral artery could be exposed with this minimum retraction of the temporal lobe in the subtemporal approach and the MTPA. By using the MTPA, 1 patient harboring a ruptured PCA aneurysm underwent superficial temporal artery-PCA anastomosis followed by isolation of the aneurysm.

RESULTS

In the cadaver head dissections, we noticed that the PCAs were difficult to expose with gentle retraction of the temporal lobe in the subtemporal approach. By performing an additional retrolabyrinthine mastoidectomy, performed as the MTPA, all 4 PCAs were easily exposed in the 4 wide surgical fields. The maximum widths of the surgical fields above and below the PCA could be successfully measured in 2 cases, which were 13.3 mm and 11.2 mm, respectively (mean, 12.3 mm). Additionally, in the actual live surgery using MTPA, the PCAs were relative easy to expose with a surgical field wide enough to perform PCA bypass, which was performed without complication.

CONCLUSION

The MTPA may be the most favorable approach for PCA bypass that can be performed easily with minimal temporal lobe retraction.