Review of endovascular stent‐assisted embolization for management of intracranial aneurysms

Objective: This was a retrospective review of the results using stent‐assisted coil embolization for management of intracranial aneurysms. Methods: The records of seven patients treated with stent‐assisted Gugliemi detachable coil (GDC) embolization were retrieved from the authors’ prospectively maintained database. The clinical presentation, site and type of aneurysms, treatment procedure and complications, and outcome of these identified cases were reviewed. Results: Between January 2002 and May 2004, seven patients with intracranial aneurysms, four of which were ruptured, were treated by stent‐assisted GDC embolization. Four aneurysms were located at the anterior circulation and three were at the posterior circulation. The indications for stent use were: giant aneurysm (>2.5 cm), dissecting pseudo‐aneurysm, broad‐necked aneurysm and the need for preservation of important parent arteries or branches. Concerning the technical aspect, all except one had successful stent deployment. One stent dislodged after apparent successful deployment. GDC embolization was continued and the aneurysm was partially occluded. More than 90% occlusion of aneurysm sac was achieved in six aneurysms. Intraoperative complications included over‐coagulation, failure in stent deployment, displacement of stent, coil entrapment and thromboembolism. One patient had added focal neurological deficit after the procedure, and one became vegetative due to an unrelated cause. The patient in whom the stent was dislodged suffered another subarachnoid haemorrhage 4 months later and died. Conclusion: Percutaneous intracranial stent is a new and useful device to assist embolization of cerebral aneurysms that were previously not amenable to endovascular therapy. These preliminary results suggest that this procedure could achieve satisfactory outcomes without significant complications.     

Technical skills assessment as part of the selection process for a fellowship in minimally invasive surgery

Introduction

Selection of candidates for surgical fellowships has traditionally been based on subjective evaluations by the program directors and references from previous positions. The introduction of well-validated objective methods of assessment has allowed us to evaluate candidates’ technical skills and base the selection process on objective, reliable, and transparent criteria. The aim of the study was to assess the applicability of such methods in current practice.

Materials and methods

Prospective study. Eight surgeons, applying for a fellowship position in minimally invasive surgery (MIS), performed a previously validated assessment curriculum using a Virtual-Reality Laparoscopic Trainer (LapSim^® 3.0, Surgical Science, Gothenburgh, Sweden). Technical performance was evaluated using criteria registered by the simulator, i.e., time, error score, and efficiency of movements score. Candidates performed all the tasks in easy end medium level until reaching predefined criteria. If proficiency criteria were not achieved on easy or medium level after nine repetitions the test was considered as failed. Additionally, all applicants underwent an interview by two independent attending surgeons. Each applicant received a grade on a ten-point scale.

Results

Five out of the eight candidates failed the technical skills assessment test. One candidate failed to achieve proficiency criteria on easy level, one on medium, and three on difficult level. Evaluation scores, based on the interview of the candidates showed a good interrater reliability (Cronbach’s α = 0.8). There was no significant correlation between the interviewers rating, and the applicants technical skills demonstrated during the test on the VR trainer (Spearman’s ρ = 0.182, p = 0.696).

Conclusions

Evaluations by senior surgeons are reproducible and reliable. The introduction of technical skills assessment has the potential to improve the current method of candidate selection, making it more valid, objective, and transparent.     

Experience matters: comparing novice and expert ratings of non‐technical skills using the NOTSS system

There is growing evidence that non‐technical skills (NTS) are related to surgical outcomes and patient safety. The aim of this study was to further evaluate a behaviour rating system (NOTSS: Non‐Technical Skills for Surgeons) which can be used for workplace assessment of the cognitive and social skills which are essential components of NTS. A novice group composed of consultant surgeons (n = 44) from five Scottish hospitals attended one of six experimental sessions and were trained to use the NOTSS system. They then used NOTSS to rate surgeons’ behaviors in six simulated scenarios filmed in the operating room. The behaviours demonstrated in each scenario were compared to expert ratings to determine accuracy. The mode rating from the novice group (who received a short training session in behaviour assessment) was the same as the expert group in 50% of ratings. Where there was disagreement, novice raters tended to provide lower ratings than the experts. Novice raters require significant training in this emerging area of competence in order to accurately rate non‐technical skills.     

Optimizing a micro‐computed tomography‐based surrogate measurement of bone‐implant contact

Histology and backscatter scanning electron microscopy (bSEM) are the current gold standard methods for quantifying bone‐implant contact (BIC), but are inherently destructive. Microcomputed tomography (μCT) is a non‐destructive alternative, but attempts to validate μCT‐based assessment of BIC in animal models have produced conflicting results. We previously showed in a rat model using a 1.5 mm diameter titanium implant that the extent of the metal‐induced artefact precluded accurate measurement of bone sufficiently close to the interface to assess BIC. Recently introduced commercial laboratory μCT scanners have smaller voxels and improved imaging capabilities, possibly overcoming this limitation. The goals of the present study were to establish an approach for optimizing μCT imaging parameters and to validate μCT‐based assessment of BIC. In an empirical parametric study using a 1.5 mm diameter titanium implant, we determined 90 kVp, 88 µA, 1.5 μm isotropic voxel size, 1600 projections/180°, and 750 ms integration time to be optimal. Using specimens from an in vivo rat experiment, we found significant correlations between bSEM and μCT for BIC with the manufacturer's automated analysis routine (r = 0.716, p = 0.003) or a line‐intercept method (r = 0.797, p = 0.010). Thus, this newer generation scanner's improved imaging capability reduced the extent of the metal‐induced artefact zone enough to permit assessment of BIC. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:979–986, 2018.

     

New three‐dimensional head‐mounted display system,TMDU‐S‐3D system,for minimally invasive surgery application: Procedures for gasless single‐port radical nephrectomy

We present an application of a new three‐dimensional head‐mounted display system that combines a high‐definition three‐dimensional organic electroluminescent head‐mounted display with a high‐definition three‐dimensional endoscope to minimally invasive surgery, using gasless single‐port radical nephrectomy procedures as a model. This system presents the surgeon with a higher quality of magnified three‐dimensional imagery in front of the eyes regardless of head position, and simultaneously allows direct vision by moving the angle of sight downward. It is also significantly less expensive than the current robotic surgery system. While carrying out gasless single‐port radical nephrectomy, the system provided the surgeon with excellent three‐dimensional imagery of the operative field, direct vision of the outside and inside of the patient, and depth perception and tactile feedback through the devices. All four nephrectomies were safely completed within the operative time, blood loss was within usual limits and there were no complications. The display was light enough to comfortably be worn for a long operative time. Our experiences show that the three‐dimensional head‐mounted display system might facilitate maneuverability and safety in minimally invasive procedures, without prohibitive cost, and thus might mitigate the drawbacks of other three‐dimensional vision systems. Because of the potential benefits that this system offers, it deserves further refinements of its role in various minimally invasive surgeries.