3D Neurotrainer

3D Neurotrainer

The joint work of neurosurgeons of the University General Hospital of Alicante and a toy company of Onil has resulted in a pioneering advance in the treatment of tumors at the base of the brain. This is a 3D printed surgical simulation model, presented in the framework of the XIV National Congress of the Spanish Society of Skull Base Pathology that took place in the hospital. Those responsible said that, after being improved and implemented, it will also be announced next November at a medical meeting in Orlando.

According to Pablo González, neurosurgeon of the Hospital and member of the Neurosciences Group of the Institute of Sanitary and Biomedical Research of Alicante (Isabial), the main advance of this model is that it allows to simulate a surgery in real conditions, not only seeing the anatomy of the area but the distortion caused by that injury at the base of the brain. They started from a few models developed three years ago together with the Bioengineering department of the Miguel Hernández University (UMH) of Elche, to which the German toy company Sempere de Onil has now been incorporated, which has made the technology available to medicine impression they use to make dolls. The novelty lies, above all, in the choice of the materials used, which perfectly reproduce the real organs and even the textures of the tumor to be treated.

One of the advantages of this system is that it allows planning the surgical activity, carrying it out in the most realistic conditions possible. In addition, a system of detection of nerves and more important neural structures has been incorporated, which guides the surgeon. “When we are 10 millimeters from the nerves, it emits intermittent beeps, similar to the assistant to park the car, and when the distance is two, the frequency of the sound is continued,” said Dr. González López, who also highlighted the help he gives to the surgeon in terms of anatomical orientation.

Dr. Javier Abarca, a neurosurgeon at the Skull Base Unit, said that so far these types of surgeries were performed by dissecting them in bodies, using virtual surgical planning models or synthetic prototypes. Now it has managed to combine all that and it has also improved, allowing to perform the surgery in the most realistic way possible. «In the models made with plastic, when we broke the part that simulated the bone with an engine it was burned. However, with the material used now, the material splinters forming chips with the same consistency. It looks like a real surgery, ”he said.

Now, the goal is to improve the model, reproducing even other anatomical regions. Although both the generation of the files used for three-dimensional reproduction and printing – which lasts between 90 and 100 hours – are complicated processes, the idea is to be able to “customize” each model to simulate real scenarios.

Dr. Irene Monjas, otolaryngologist at the Hospital de Alicante, stressed the progress of replacing anatomical specimens with this simulator, less and less available and at a much higher cost. “In addition, this makes it possible to reproduce exactly the pathologies to be treated, plan operations and even become a learning tool for residents,” he said.

In the General Hospital of Alicante about forty or fifty interventions are performed a year at the base of the brain, between vestibular schwannomas, meningiomas of the posterior fossa and epidermoid tumors. Although fortunately most tumors in this area are benign (95%), if they are not operated it can end up affecting the nerves and neural structures and even plugging a circuit of fluid circulation in the brain, causing hydrocephalus, which is potentially serious In addition, these tumors experience very slow growth, which helps to generate the model and plan the surgery with time until it is optimal. “The objective is to be able to operate these pathologies and above all without affecting the nervous structures,” said Dr. Gonzalez after the operating simulation performed before the leading figures in neurosurgery worldwide.

THE SECRETS OF ‘3D NEUROTRAINER’

Materials. For the first time, it has been possible to manufacture operable tumors, with materials that simulate the tissues with great precision, created individually for patients to be treated in the future.

Alarm system. Toy engineers have even included an acoustic and visual alarm system to save important nerve structures and make the approach safer.

Substitution. This training model will serve as a complement to the usual study of anatomy in corpses, since it provides benefits, such as availability, biosecurity and the ability to develop individual models, simulating with great precision the pathology of each patient.

Ponticulus posticus

Ponticulus posticus

The ponticulus posticus is a bony bridge in the atlas between the lateral mass and the posterior arch. It results due to ossification of the posterior atlantooccipital ligament of atlas and encloses the vertebral artery and the first cervical nerve root.

It is a normal anatomical variant of atlas vertebrae (C1) and resides in the posterior arch of atlas in relation to the vertebral artery. It is an incidental finding visualised from lateral cephalograms taken for routine orthodontic treatment purposes. Ponticulus posticus in Latin means ‘little posterior bridge’. Other synonyms for ponticulus are arcuate foramen, kimerle anomaly, retroarticular foramen and retocondylar foramen.

An overall incidence of ponticulus posticus has been reported to be 16.7%. Literature reveals a higher incidence in females compared with males and this anomaly was age-independent.

Diagnosis

Failure to detect ponticulus posticus can have grave complications during cervical spine surgical intervention, especially those requiring screw placement in lateral mass region of Atlas vertebra 1).


Consecutive computed tomography scans (n=210) were reviewed for PP and high-riding vertebral artery (HRVA) (defined as an internal height of <2 mm and an isthmus height of <5 mm). In scans with PP+HRVA, we measured the ipsilateral pedicle width, pars length, and laminar thickness and compared them with controls (those without PP or HRVA).

PP was present in 14.76% and HRVA in 20% of scans. Of the 420 sides in 210 scans, PP+HRVA was present on 13 sides (seven right and six left). In scans with PP+HRVA, the length of the C2 par was shorter compared with controls (13.69 mm in PP+HRVA vs. 20.65 mm in controls, p<0.001). The mean C2 pedicle width was 2.53 mm in scans with PP+HRVA vs. 5.83 mm in controls (p<0.001). The mean laminar thickness was 4.92 and 5.48 mm in scans with PP+HRVA and controls, respectively (p=0.209).

The prevalence of PP+HRVA was approximately 3% in the present study. Our data suggest that, in such situations, C2 pedicle width and pars length create important safety limitations for a proposed screw, whereas the translaminar thickness appears safe for a proposed screw 2).


In CT scans some anomalies, such as abnormal facet complex and arch anomalies, have to be differentiated from fractures in a trauma patient. Other anomalies, like PP, have to be looked for during preoperative planning to avoid complications during surgery. Therefore, knowledge of these anomalies is important as different anomalies have different clinical courses and management 3).

Case series

Thirty-three consecutive patients with unstable odontoid fractures underwent Goel technique and Harms technique (C1–2 arthrodesis). Surgery was performed with the aid of lateral fluoroscopy control in 16 cases (control group) that was supplemented by Doppler ultrasonography in 17 cases (Doppler group). Two patients in each group had a C1 ponticulus posticus. In the Doppler group, Doppler probing was performed during lateral subperiosteal muscle dissection, stepwise drilling, and tapping. Blood flow velocity in the V3 segment of the VA was recorded before and after posterior arthrodesis. All patients had a 12-month outpatient follow-up, and the outcome was assessed using the Smiley-Webster Pain Scale. Neither VAI nor postoperative neurological impairments were observed in the Doppler group. In the control group, VAIs occurred in the 2 patients with C1 ponticulus posticus. In the Doppler group, 1 patient needed intra- and postoperative blood transfusions, and no difference in terms of Doppler signal or VA blood flow velocity was detected before and after C1-C2 posterior arthrodesis. In the control group, 3 patients needed intra- and postoperative blood transfusions.Useful in supporting fluoroscopy-assisted procedures, intraoperative Doppler may play a significant role even during surgeries in which neuronavigation is used, reducing the chance of a mismatch between the view on the neuronavigation screen and the actual course of the VA in the operative field and supplying the additional data of blood flow velocity 4).

References

1)

Elliott RE, Tanweer O. The prevalence of the ponticulus posticus (arcuate foramen) and its importance in the Goel-Harms procedure: meta-analysis and review of the literature. World Neurosurg. 2014 Jul-Aug;82(1-2):e335-43. doi: 10.1016/j.wneu.2013.09.014. Epub 2013 Sep 18. Review. PubMed PMID: 24055572.
2)

Kothari MK, Dalvie SS, Gupta S, Tikoo A, Singh DK. The C2 Pedicle Width, Pars Length, and Laminar Thickness in Concurrent Ipsilateral Ponticulus Posticus and High-Riding Vertebral Artery: A Radiological Computed Tomography Scan-Based Study. Asian Spine J. 2019 Apr;13(2):290-295. doi: 10.31616/asj.2018.0057. Epub 2018 Dec 7. PubMed PMID: 30521747; PubMed Central PMCID: PMC6454277.
3)

N V A, Avinash M, K S S, Shetty AP, Kanna RM, Rajasekaran S. Congenital Osseous Anomalies of the Cervical Spine: Occurrence, Morphological Characteristics, Embryological Basis and Clinical Significance: A Computed Tomography Based Study. Asian Spine J. 2019 Mar 14:535-543. doi: 10.31616/asj.2018.0260. [Epub ahead of print] PubMed PMID: 30866614; PubMed Central PMCID: PMC6680038.
4)

Lofrese G, Cultrera F, Visani J, Nicassio N, Essayed W, Donati R, Cavallo MA, De Bonis P. Intraoperative Doppler ultrasound as a means of preventing vertebral artery injury during Goel and Harms C1-C2 posterior arthrodesis: technical note. J Neurosurg Spine. 2019 Aug 16:1-7. doi: 10.3171/2019.5.SPINE1959. [Epub ahead of print] PubMed PMID: 31419805.

Medical student

Medical student

For students beginning their medical education, the neuroscience curriculum is frequently seen as the most difficult, and many express an aversion to the topic. A major reason for this aversion amongst learners is the perceived complexity of neuroanatomy 1).

Osler created the first residency program for specialty training of physicians, and he was the first to bring medical students out of the lecture hall for bedside clinical training. Historically, medical student education in neurological surgery has generally limited student involvement to assisting in research projects with minimal formal clinical exposure before starting sub-internships and application for the neurosurgery match. Consequently, students have generally had little opportunity to acquire exposure to clinical neurosurgery and attain minimal proficiency 2).

Neurosurgery seeks to attract the best and brightest medical students; however, there is often a lack of early exposure to the field, among other possible barriers.

United States

Lubelski et al. sought to identify successful practices that can be implemented to improve medical student recruitment to neurosurgery.

United States neurosurgery residency program directors were surveyed to determine the number of medical student rotators and medical students matching into a neurosurgery residency from their programs between 2010 and 2016. Program directors were asked about the ways their respective institutions integrated medical students into departmental clinical and research activities.

Complete responses were received from 30/110 institutions. Fifty-two percent of the institutions had neurosurgery didactic lectures for 1st- and 2nd-year medical students (MS1/2), and 87% had didactics for MS3/4. Seventy-seven percent of departments had a neurosurgery interest group, which was the most common method used to integrate medical students into the department. Other forms of outreach included formal mentorshipprograms (53%), lecture series (57%), and neurosurgery anatomy labs (40%). Seventy-three percent of programs provided research opportunities to medical students, and 57% indicated that the schools had a formal research requirement. On average, 3 medical students did a rotation in each neurosurgery department and 1 matched into neurosurgery each year. However, there was substantial variability among programs. Over the 2010-2016 period, the responding institutions matched as many as 4% of the graduating class into neurosurgery per year, whereas others matched 0%-1%. Departments that matched a greater (≥ 1% per year) number of medical students into neurosurgery were significantly more likely to have a neurosurgery interest group and formal research requirements. A greater percentage of high-matching programs had neurosurgery mentorship programs, lecture series, and cadaver training opportunities compared to the other institutions.

In recent decades, the number of applicants to neurosurgery has decreased. A major deterrent may be the delayed exposure of medical students to neurosurgery. Institutions with early preclinical exposure, active neurosurgery interest groups, research opportunities, and strong mentorship recruit and match more students into neurosurgery. Implementing such initiatives on a national level may increase the number of highly qualified medical students pursuing neurosurgery 3).


A medical student training camp was created to improve the preparation of medical students for the involvement in neurological surgery activities and sub-internships.

A 1-day course was held at Weill Cornell Medicine, which consisted of a series of morning lectures, an interactive resident lunch panel, and afternoon hands-on laboratory sessions. Students completed self-assessment questionnaires regarding their confidence in several areas of clinical neurosurgery before the start of the course and again at its end.

A significant increase in self-assessed confidence was observed in all skill areas surveyed. Overall, rising fourth year students who were starting sub-internships in the subsequent weeks reported a substantial increase in their preparedness for the elective rotations in neurosurgery.

The preparation of medical students for clinical neurosurgery can be improved. Single-day courses such as the described training camp are an effective method for improving knowledge and skill gaps in medical students entering neurosurgical careers. Initiatives should be developed, in addition to this annual program, to increase the clinical and research skills throughout medical student education 4).

Canada

Medical students in Canada must make career choices by their final year of medical school. Selection of students for a career in neurosurgery has traditionally been based on marks, reference letters and personal interviews. Studies have shown that marks alone are not accurate predictors of success in medical practice; personal skills and attributes which can best be assessed by reference letters and interviews may be more important. A study was an attempt to assess the importance of, and ability to teach, personal skills and attitudes necessary for successful completion of a neurosurgical training program.

questionnaire was sent to 185 active members of the Canadian Neurosurgical Society, asking them to give a numerical rating of the importance of 22 personal skills and attributes, and their ability to teach those skills and attributes. They were asked to list any additional skills or attributes considered important, and rate their ability to teach them.

Sixty-six (36%) questionnaires were returned. Honesty, motivation, willingness to learn, ability to problem solve, and ability to handle stress were the five most important characteristics identified. Neurosurgeons thought they could teach problem solving, willingness to consult informed sources, critical thinking, manual dexterity, and communication skills, but honesty, motivation, willingness to learn and ability to handle stress were difficult or impossible to teach.

Honestymotivationwillingness to learnproblem solving and Stress management are important for success in a neurosurgical career. This information should be transmitted to medical students at “Career Day” venues. Structuring letters of reference and interviews to assess personal skills and attributes will be important, as those that can’t be taught should be present before the start of training 5).

References

1)

Larkin MB, Graves E, Rees R, Mears D. A Multimedia Dissection Module for Scalp, Meninges, and Dural Partitions. MedEdPORTAL. 2018 Mar 22;14:10695. doi: 10.15766/mep_2374-8265.10695. PubMed PMID: 30800895; PubMed Central PMCID: PMC6342347.
2) , 4)

Radwanski RE, Winston G, Younus I, ElJalby M, Yuan M, Oh Y, Gucer SB, Hoffman CE, Stieg PE, Greenfield JP, Pannullo SC. Neurosurgery Training Camp for Sub-Internship Preparation: Lessons From the Inaugural Course. World Neurosurg. 2019 Apr 1. pii: S1878-8750(19)30926-X. doi: 10.1016/j.wneu.2019.03.246. [Epub ahead of print] PubMed PMID: 30947014.
3)

Lubelski D, Xiao R, Mukherjee D, Ashley WW, Witham T, Brem H, Huang J, Wolfe SQ. Improving medical student recruitment to neurosurgery. J Neurosurg. 2019 Aug 9:1-7. doi: 10.3171/2019.5.JNS1987. [Epub ahead of print] PubMed PMID: 31398709.
5)

Myles ST, McAleer S. Selection of neurosurgical trainees. Can J Neurol Sci. 2003 Feb;30(1):26-30. PubMed PMID: 12619780.
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