Microsurgical training: vascular control and intraoperative vessel rupture in the human placenta infusion model

Acta Neurochirurgica (2021) 163:2525–2532

Microsurgery is a challenging discipline. Regular lab training under the operating microscope has been the environment where most surgeons have mastered the skills and techniques inherent to most microneurosurgical procedures. However, some critical scenarios remain difficult to master or simulate. We describe a step-by-step method for how to build a low-cost, feasible, and widely available model that allows residents to familiarize themselves with demanding critical situations such as intraoperative rupture of major vessels.

Methods After delivery, nine fresh human placentas were transferred to the lab. The umbilical vein was cannulated for normal saline infusion. Several hands-on procedures were performed under direct microscope vision. Operating microscope setup, allantoic membrane splitting, vascular dissection and vessel injury, and repair exercises were simulated and video recorded. Indocyanine green was administered to simulate intraoperative angiography.

Results The model can be setup in less than 15 min, with minimal cost and infrastructure requirements. All the exercises described above can be conducted with a single placenta. Umbilical vein cannulation adds realism and allows quantification of the volume of saline required to complete the exercise. The final check with indocyanine green simulates intraoperative angiography and allows the assessment of distal vessel patency.

Conclusions Minimal infrastructure requirements, simplicity, and easy setup models provide a suitable environment for regular training. The human placenta is inexpensive and widely available, making it a feasible model for residents training. Neurosurgery residents may benefit from this model to familiarize with microsurgery and critical scenarios in a risk-free environment without time or resource constraints.

Neurosurgical simulator for training aneurysm microsurgery

Acta Neurochirurgica (2020) 162:2313–2321

Due to its complexity and to existing treatment alternatives, exposure to intracranial aneurysm microsurgery at the time of neurosurgical residency is limited. The current state of the art includes training methods like assisting in surgeries, operating under supervision, and video training. These approaches are labor-intensive and difficult to fit into a timetable limited by the new work regulations. Existing virtual reality (VR)–based training modules lack patient-specific exercises and haptic properties and are thus inferior to hands-on training sessions and exposure to real surgical procedures.

Materials and methods We developed a physical simulator able to reproduce the experience of clipping an intracranial aneurysm based on a patient-specific 3D-printed model of the skull, brain, and arteries. The simulator is made of materials that not only imitate tissue properties including arterial wall patency, thickness, and elasticity but also able to recreate a pulsatile blood flow. A sample group of 25 neurosurgeons and residents (n = 16: early residency with less than 4 years of neurosurgical exposure; n = 9: late residency and board-certified neurosurgeons, 4–15 years of neurosurgical exposure) took part to the study. Participants evaluated the simulator and were asked to answer questions about surgical simulation anatomy, realism, haptics, tactility, and general usage, scored on a 5-point Likert scale. In order to evaluate the feasibility of a future validation study on the role of the simulator in neurosurgical postgraduate training, an expert neurosurgeon assessed participants’ clipping performance and a comparison between groups was done.

Results The proposed simulator is reliable and potentially useful for training neurosurgical residents and board-certified neurosurgeons. A large majority of participants (84%) found it a better alternative than conventional neurosurgical training methods.

Conclusion The integration of a new surgical simulator including blood circulation and pulsatility should be considered as part of the future armamentarium of postgraduate education aimed to ensure high training standards for current and future generations of neurosurgeons involved in intracranial aneurysm surgery. Resident training ,Surgical simulation,Surgical education ,Microsurgery , Intracranial aneurysm , Neurosurgery

Patient-specific 3-dimensionally printed models for neurosurgical planning and education

Neurosurg Focus 47 (6):E12, 2019

Advances in 3-dimensional (3D) printing technology permit the rapid creation of detailed anatomical models. Integration of this technology into neurosurgical practice is still in its nascence, however. One potential application is to create models depicting neurosurgical pathology. The goal of this study was to assess the clinical value of patientspecific 3D printed models for neurosurgical planning and education.

METHODS The authors created life-sized, patient-specific models for 4 preoperative cases. Three of the cases involved adults (2 patients with petroclival meningioma and 1 with trigeminal neuralgia) and the remaining case involved a pediatric patient with craniopharyngioma. Models were derived from routine clinical imaging sequences and manufactured using commercially available software and hardware.

RESULTS Life-sized, 3D printed models depicting bony, vascular, and neural pathology relevant to each case were successfully manufactured. A variety of commercially available software and hardware were used to create and print each model from radiological sequences. The models for the adult cases were printed in separate pieces, which had to be painted by hand, and could be disassembled for detailed study, while the model for the pediatric case was printed as a single piece in separate-colored resins and could not be disassembled for study. Two of the models were used for patient education, and all were used for presurgical planning by the surgeon.

CONCLUSIONS Patient-specific 3D printed models are useful to neurosurgical practice. They may be used as a visualization aid for surgeons and patients, or for education of trainees.

Microsurgery Simulator of Cerebral Aneurysm Clipping with Interactive Cerebral Deformation Featuring a Virtual Arachnoid

Operative Neurosurgery 14:579–589, 2018

A virtual reality simulator for aneurysmal clipping surgery is an attractive research target for neurosurgeons. Brain deformation is one of the most important functionalities necessary for an accurate clipping simulator and is vastly affected by the status of the supporting tissue, such as the arachnoid membrane. However, no virtual reality simulator implementing the supporting tissue of the brain has yet been developed.

OBJECTIVE: To develop a virtual reality clipping simulator possessing interactive brain deforming capability closely dependent on arachnoid dissection and apply it to clinical cases.

METHODS: Three-dimensional computer graphics models of cerebral tissue and surrounding structureswere extracted frommedical images.We developed a new method formodifiable cerebral tissue complex deformation by incorporating a nonmedical imagederived virtual arachnoid/trabecula in a process called multitissue integrated interactive deformation (MTIID). MTIID made it possible for cerebral tissue complexes to selectively deform at the site of dissection. Simulations for 8 cases of actual clipping surgery were performed before surgery and evaluated for their usefulness in surgical approach planning.

RESULTS: Preoperatively, each operative field was precisely reproduced and visualized with the virtual brain retraction defined by users. The clear visualization of the optimal approach to treating the aneurysmvia an appropriate arachnoid incision was possiblewith MTIID.

CONCLUSION: A virtual clipping simulatormainly focusing on supporting tissues and less on physical properties seemed to be useful in the surgical simulation of cerebral aneurysm clipping. To our knowledge, this article is the first to report brain deformation based on supporting tissues.

KEYWORDS: Virtual reality, Clipping, Aneurysm, Deformation, Arachnoid, Simulation

 

Interactive iBook-Based Patient Education in a NeuroTrauma Clinic

Neurosurgery 81:787–794, 2017

Traumatic brain injury (TBI) is a leading cause of death and disability in the United States. Educational interventions may alleviate the burden of TBI for patients and their families. Interactive modalities that involve engagement with the educational material may enhance patient knowledge acquisition when compared to static text-based educational material.

OBJECTIVE: To determine the effects of educational interventions in the outpatient setting on self-reported patient knowledge, with a focus on iPad-based (Apple, Cupertino, California) interactive modules.

METHODS: Patients and family members presenting to a NeuroTrauma clinic at a tertiary care academic medical center completed a presurvey assessing baseline knowledge of TBI or concussion, depending on the diagnosis. Subjects then received either an interactive iBook (Apple) on TBI or concussion, or an informative pamphlet with identical information in text format. Subjects then completed a postsurvey prior to seeing the neurosurgeon.

RESULTS: All subjects (n = 152) significantly improved on self-reported knowledge measures following administration of either an iBook (Apple) or pamphlet (P < .01, 95% confidence interval [CI]). Subjects receiving the iBook (n = 122) performed significantly better on the postsurvey (P < .01, 95% CI), despite equivalent presurvey scores, when compared to those receiving pamphlets (n = 30). Lastly, patients preferred the iBook to pamphlets (P < .01, 95% CI).

CONCLUSION: Educational interventions in the outpatient NeuroTrauma setting led to significant improvement in self-reported measures of patient and family knowledge. This improved understanding may increase compliance with the neurosurgeon’s recommendations and may help reduce the potential anxiety and complications that arise following a TBI.

A basic model for training of microscopic and endoscopic transsphenoidal pituitary surgery: the Egghead

A basic model for training of microscopic and endoscopic transsphenoidal pituitary surgery- the Egghead

Acta Neurochir (2015) 157:1771–1777

Transsphenoidal endoscopic surgery has gained popularity in the last 2 decades and is becoming a standard technique for resection of pituitary adenomas. In contrast to their ENT colleagues, neurosurgical residents have practically no endoscopic experience when they reach the training stage for transsphenoidal procedures.

We have developed an affordable method for repetitive training in endoscopic (and microscopic) work in a narrow channel, allowing training of the basic movements needed for resection of pituitary adenoma.

Methods In collaboration with colleagues in the ENT Department, Cantonal Hospital St. Gall, and the Technical University of Zurich, a three-dimensional model of the nasal cavity was developed and patented. The Egghead model consists of a 3D synthetic reconstruction of the head nasal cavity and sphenoid sinus. A boiled egg represents the sella. For validation, 17 neurosurgical residents from the Department of Neurosurgery, University Hospital of Basel, and Department of Neurosurgery, Cantonal Hospital of St. Gall, St. Gall, Switzerland, and two experts performed a standardized procedure mimicking a transsphenoidal pituitary procedure by dissecting a corridor to the egg yolk and resecting it, respecting the surrounding egg white. This procedure was performed under both microscopic and video-endoscopic visualization. A score for the precision and speed of the surgical performance was developed and used.

Results The model allows repetitive training of the resection of the egg yolk under sparing of the egg white after careful opening of the shell. The validation data showed a steeper learning curve using the endoscopic technique than performing the same task using the microscope. After three repetitions, the quality of resection was better with the endoscopic technique.

Conclusions Our model, the Egghead, is affordable, offers tactile feedback and allows infinite repetitions in basic training for pituitary surgery. It can be used for training of advanced neurosurgical residents, who thus far have very few possibilities of acquiring endoscopic experience.

Development and validation of an artificial wetlab training system for the lumbar discectomy

Development and validation of an artificial wetlab training system for the lumbar discectomy

Eur Spine J (2014) 23:1978–1983

An initial research indicated that realistic haptic simulators with an adapted training concept are needed to enhance the training for spinal surgery.

Methods A cognitive task analysis (CTA) was performed to define a realistic and helpful scenario-based simulation. Based on the results a simulator for lumbar discectomy was developed. Additionally, a realistic training operating room was built for a pilot. The results were validated.

Results The CTA showed a need for realistic scenariobased training in spine surgery. The developed simulator consists of synthetic bone structures, synthetic soft tissue and an advanced bleeding system. Due to the close interdisciplinary cooperation of surgeons between engineers and psychologists, the iterative multicentre validation showed that the simulator is visually and haptically realistic. The simulator offers integrated sensors for the evaluation of the traction being used and the compression during surgery. The participating surgeons in the pilot workshop rated the simulator and the training concept as very useful for the improvement of their surgical skills.

Conclusions In the context of the present work a precise definition for the simulator and training concept was developed. The additional implementation of sensors allows the objective evaluation of the surgical training by the trainer. Compared to other training simulators and concepts, the high degree of objectivity strengthens the acceptance of the feedback. The measured data of the nerve root tension and the compression of the dura can be used for intraoperative control and a detailed postoperative evaluation.

Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons

Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons

J Neurosurg 120:489–492, 2014

The advent of multimaterial 3D printers allows the creation of neurosurgical models of a more realistic nature, mimicking real tissues.

The authors used the latest generation of 3D printer to create a model, with an inbuilt pathological entity, of varying consistency and density. Using this model the authors were able to take trainees through the basic steps, from navigation and planning of skin flap to performing initial steps in a craniotomy and simple tumor excision.

As the technology advances, models of this nature may be able to supplement the training of neurosurgeons in a simulated operating theater environment, thus improving the training experience

The first 50s: can we achieve acceptable results in vestibular schwannoma surgery from the beginning?

Acta Neurochir (2010) 152:1359–1365. DOI 10.1007/s00701-010-0672-z

Vestibular schwannoma surgery requires a profound knowledge of anatomy and long-standing experience of surgical skull base techniques, as patients nowadays requests high-quality results from any surgeon. This educes a dilemma for the young neurosurgeon as she/he is at the beginning of a learning curve. The presented series should prove if surgical results of young skull base surgeons are comparable respecting carefully planned educational steps.

Methods: The first 50 vestibular schwannomas of the first author were retrospectively evaluated concerning morbidity and mortality with an emphasis on functional cranial nerve preservation. The results were embedded in a timeline of educational steps starting with the internship in 1999.

Results: Fifty vestibular schwannomas were consecutively operated from July 2007 to January 2010. According to the Hannover Classification, 14% were rated as T1, 18% as T2, 46% as T3, and 21% as T4. The overall facial nerve preservation rate was 96%. Seventy-nine percent of patients with T1–T3 tumours had no facial palsy at all and 15% had an excellent recovery of an initial palsy grade 3 according to the House & Brackman scale within the first 3 months after surgery. Hearing preservation in T1/2 schwannomas was achieved in 66%, in patients with T3 tumours in 56%, and in large T4 tumours in 25%. Three patients suffered a cerebrospinal fluid fistula (6%), and one patient died during the perioperative period due to cardiopulmonary problems (2%).

Conclusions: The results demonstrate that with careful established educational plans in skull base surgery, excellent clinical and functional results can be achieved even by young neurosurgeons.

Web-based audiovisual patient information system—a study of preoperative patient information in a neurosurgical department

Acta Neurochir (2010) 152:1337–1341. DOI 10.1007/s00701-010-0663-0

In the current climate of increasing awareness, patients are demanding more knowledge about forthcoming operations. The patient information accounts for a considerable part of the physician’s daily clinical routine. Unfortunately, only a small percentage of the information is understood by the patient after solely verbal elucidation. To optimise information delivery, different auxiliary materials are used.

Methods In a prospective study, 52 consecutive stationary patients, scheduled for an elective lumbar disc operation were asked to use a web-based audiovisual patient information system. A combination of pictures, text, tone and video about the planned surgical intervention is installed on a tablet personal computer presented the day before surgery. All patients were asked to complete a questionnaire.

Results Eighty-four percent of all participants found that the audiovisual patient information system lead to a better understanding of the forthcoming operation. Eighty-two percent found that the information system was a very helpful preparation before the pre-surgical interview with the surgeon. Ninety percent of all participants considered it meaningful to provide this kind of preoperative education also to patients planned to undergo other surgical interventions. Eighty-four percent were altogether “very content” with the audiovisual patient information system and 86% would recommend the system to others.

Conclusions This new approach of patient information had a positive impact on patient education as is evident from high satisfaction scores. Because patient satisfaction with the informed consent process and understanding of the presented information improved substantially, the audiovisual patient information system clearly benefits both surgeons and patients.

Three-dimensional simulation for aneurysm surgery

Neurosurgery 65:719–726, 2009 DOI: 10.1227/01.NEU.0000354350.88899.07

OBJECTIVE: With improvements in endovascular techniques, fewer aneurysms are treated by surgical clipping, and those aneurysms targeted for open surgery are often complex and difficult to treat. We devised a hollow, 3-dimensional (3D) model of individual cerebral aneurysms for preoperative simulation and surgical training. The methods and initial experience with this model system are presented.

METHODS:The 3D hollow aneurysm models of 3 retrospective and 8 prospective cases were made with a prototyping technique according to data from 3D computed tomographic angiograms of each patient. Commercially available titanium clips used in our routine surgery were applied, and the internal lumen was observed with an endoscope to confirm the patency of parent vessels. The actual surgery was performed later.

RESULTS: In the 8 prospective cases, the clips were applied during surgery in the same direction and configuration as in the preoperative simulation. Fine adjustments were necessary in each case, and 2 patients needed additional clips to occlude the atherosclerotic aneurysmal wall. With these 3D models, it was easy for neurosurgical trainees to grasp the vascular configuration and the concept of neck occlusion. Practicing surgery with these models also improved their handling of the instruments used during

aneurysm surgery, such as clips and appliers.

CONCLUSION: Using the hollow 3D models to simulate clipping preoperatively, we could treat the aneurysms confidently during live surgery. These models allow easy and concrete recognition of the 3D configuration of aneurysms and parent vessels.

Lessons learned by personal failures in aneurysm surgery: what went wrong, and why?

Knut Wester

Acta Neurochir (2009) 151:1013–1024


Purpose To analyse the intraoperative complications of a single neurosurgeon, with emphasis on devastating intraoperative incidents, and how they possibly could have been avoided.
Methods All the patients operated upon by the author between 1986 and 2002, i.e. 252 patients with 270 craniotomies for 294 aneurysms, were included. All intraoperative events that possibly could have influenced the clinical outcome were recorded prospectively.
Results A total of 16 cases (6.3% of all the patients) with serious intraoperative incidents were identified. In 11 cases (3.6% of all aneurysms), an intraoperative rupture occurred that was judged to have had mild to severe consequences for the patient. In another four patients (1.6% of all patients), all with unruptured, large aneurysms (>15 mm) of the carotid or middle cerebral arteries, a major vessel occlusion occurred inadvertently. In one patient with a large, unruptured MCA aneurysm, a clip slipped after the closure of the wound, causing a fatal intracerebral haemorrhage. These events had a severe impact on the clinical outcome. In retrospect, most of these incidents could, and should have, been avoided.

Conclusions It is recommended to start the training of new aneurysm surgeons on patients with small, supratentorial, unruptured aneurysms, followed by ruptured aneurysms in all other supratentorial locations than the anterior communicating artery (ACOM), which is the supratentorial location that should be the last step in the training of independent aneurysm surgeons.

EANS YOUNG NEUROSURGEONS MEETING 2010 21ST – 24TH FEBRUARY 2010

We are delighted to open registration for the EANS Young Neurosurgeons Meeting, to be held in February 2010.   This is intended as an event which will combine fierce scientific discussion and time to socialise in an informal atmosphere – please submit your application as soon as possible – the initial response to this event has been excellent, and we anticipate a good deal of interest.

However there is always a financial risk attached to the organisation of a new event, particularly in the current economic climate, and we need the firm financial commitment of a minimum number of participants by the end of the preliminary registration period (20th September 2009) if we are definitely to go ahead with the event.

This is intended as an event organised by Young Neurosurgeons for Young Neurosurgeons – so please, register now and play your part in making our event happen, keeping in mind that we have limited places available. We hope that many alumni from the EANS Training Courses will choose to attend, and are seeking to cultivate a similar atmosphere  – however we will also be delighted to welcome those who did not attend the courses, and those from outside Europe.

The morning sessions will consist of lectures from leading figures in European Neurosurgery and a series of “Challenging Topics” in which the merits of different approaches are considered, while the evening sessions will offer a valuable opportunity for recently qualified neurosurgical specialists to present their own work (abstracts to be submitted).

We hope that both sessions will give rise to animated discussions between both participants and faculty members – which can be continued during the afternoon on the ski slopes, when we anticipate that many people will choose to take advantage of the special ski deal which we have negotiated – though Innsbruck itself also has plenty to offer non skiers.

The event is focused particularly on those who have recently qualified, and the submission of abstracts is restricted to those within six years of specialist qualification.  However registration is open to those of all ages, and we hope that the event will provide the opportunity for discussion not only with your peers, but also with senior faculty members.

Please submit your registration form to Susie Hide susie.hide@btinternet.com as soon as possible.   Susie will then send you a link to our online payment facility.  As explained above, we need your firm financial commitment prior to September 20th, and will therefore require a minimum deposit of 300 Euros to be paid within this period.