Practical guidelines for setting up neurosurgery skills training cadaver laboratory in India
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.136897
Source of Support: None, Conflict of Interest: None
Though the necessity of cadaver dissection is felt by the medical fraternity, and described as early as 600 BC, in India, there are no practical guidelines available in the world literature for setting up a basic cadaver dissection laboratory for neurosurgery skills training. Hands-on dissection practice on microscopic and endoscopic procedures is essential in technologically demanding modern neurosurgery training where ethical issues, cost constraints, medico-legal pitfalls, and resident duty time restrictions have resulted in lesser opportunities to learn. Collaboration of anatomy, forensic medicine, and neurosurgery is essential for development of a workflow of cadaver procurement, preservation, storage, dissection, and disposal along with setting up the guidelines for ethical and legal concerns.
Keywords: Cadaver, education, endoscopy, laboratory, neurosurgery, skills
"No accurate account of any part of the body, including even its skin, can be rendered without the knowledge of anatomy. Hence anyone, who wishes to acquire a through knowledge of anatomy must prepare a dead body, and carefully examine all its parts".-Sushruta Samhita (600 BC) 
The surgical domain in present form has been refined by continuous individual sophistications by thorough cadaver dissections since time immemorial. The great surgeons have spent years of their lifetime dissecting cadavers and enriched us with their experience. As a result, newer surgical approaches enable us to believe that we can operate at any part of the brain, earlier considered "No man's land".
Cadaver dissection is the nearest simulation to the surgical procedures. There is no doubt that ideal learning environment lies in a real operating room (OR) but traditional surgical teaching in the OR is no more approved in its true sense. The reasons are several folds; ethical issues, cost constraints, medico-legal pitfalls, and resident duty time restrictions to name a few. Society is now extremely intolerant to surgical pitfalls and our ORs are under continuous social, legal, and ethical surveillance. Early part of surgical learning curve should be obtained outside the OR. Artificial means of simulation may supplement; but can never be a replacement for cadaver dissection. The practice sessions on cadavers should be proportionate to the complexity of surgical approach. Here, comes the role of cadavers to authenticate a new procedure for regular surgical acceptance. Anatomic training is necessary to assist the surgeon in making the cognitive transition from the cadaver laboratory to OR. Neurosurgery Education and Training School (NETS), All India Institute of Medical Sciences (AIIMS), New Delhi has established a neurosurgery skills training laboratory. It not only provides facility for cadaver dissection to master established neurosurgical techniques but also for developing new ones.  Authors here share their experience in setting up cadaver dissection laboratory for skills training in microscopic and endoscopic neurosurgery.
Relevant literature was searched on Pubmed using keywords "cadaver lab", "cadaver dissection", "neurosurgery laboratory", and "cadaver guidelines". Total 22 articles were found, among which only four were relevant. The literature revealed history of cadaver dissection for medical practice and training, workshops and conferences for surgical practice. Only two papers elaborated endoscopic instrumentation and set up requirement for cadaver laboratories. There was no literature available on practical guidelines for establishment of skills training cadaver laboratory in India.
Cadaver procurement-medico-legal and ethical aspect
Cadaver dissection is possible only with committed efforts of Department of Anatomy, Forensic Medicine and Neurosurgery. At AIIMS, cadavers are procured in accordance with the Delhi Anatomy Act 1953. "Anatomy Act", promulgated by the legislature and published in the State Government Gazette permits use of unclaimed dead bodies for teaching and dissection purposes. It also provides guidelines for the disposal of unclaimed bodies in hospitals, prisons, and public places. ,,, "Voluntary Body Donation" is a program, where general public can will their bodies to serve the purpose of medical education and scientific studies. It is the most precious gift to mankind as it helps the whole society to learn, whereas a single organ donation (e.g. eye) helps only an individual. Moreover, proper consent is taken from the kin of the deceased especially addressing post procedure rites about disposal. This warrants proper record keeping and faith in the system [Figure 1].
Cadavers are first tested for Human Immunodeficiency Virus (HIV), Australia antigen, and Hepatitis C. However, trainees should practice universal precautions all the times. Cadavers are preserved with formaldehyde, which is colorless. Previously, preservation was performed using glutaraldehyde that left a yellowish stain. "International Agency for Research on Cancer" has classified formaldehyde under Group I: "carcinogenic to humans" , hence, it should be used at the minimal concentration (2%). Formaldehyde neutralizer, "Infutrace" or ammonium carbonate solution should be added to reduce vaporization and decrease its noxious property. , For best demonstration purposes, fresh cadavers are preferred to fixed ones.
Embalming is the process to prepare the corpse for a lifelike appearance. The embalming facility and laboratory should be well-ventilated with advanced exhaust system and laminar airflow facility. The embalming solution (Modified Thiel's) used is a mixture of 4-Chloro-3-methylphenol, ammonium nitrate, potassium nitrate, ethyleneglycol, boric acid, and 2% Formalin. , Embalming solution is introduced into vasculature through electric pump providing steady pressure for fluid circulation [Figure 2].
Plastination is a unique technique of tissue preservation developed by Dr. Gunther von Hagens at the Department of Anatomy, Heidelberg University, Germany. In plastination, water and lipids in biological specimens are replaced by polymerized resin, which are then subsequently hardened. This resin possesses certain desirable qualities like low viscosity, low vapor pressure, high melting point, compatibility with tissues, curing under specific conditions, and ability to resist yellow staining. The polymers belong to one of the three classes; silicone, epoxy, and polyester. The preserved (embalmed) body is prepared by dissection or slicing.
Brain sections can be plastinated using silicone (S10) or polyster (P40) technique. , Plastination is a four-step process of fixation (by conventional fixatives), dehydration (by acetone), forced-impregnation (vacuum forces the acetone out of and the polymer into the specimen), and hardening (curing) by silicone or polyester or epoxy.
The plastinated materials are non-toxic, non-infectious, can last indefinitely without significant deterioration, allow manipulation and palpation and can also be interfaced with computer software.  Plastinated specimens is very popular among students and faculty for the teaching of systemic anatomy, pathology, , forensic medicine, odontology, anthropology,  and veterinary science. It is now possible to relate body sections to computed tomography (CT) and magnetic resonance imaging (MRI) scans.  Plastination finds its use in teaching of endoscopic anatomy  and as a simulation tool for live surgical procedures.
Fresh and embalmed cadavers should be properly preserved for longer and complete use. Ideally, there should be a refrigerator at cadaver dissection facility itself, maintained at −40oC. However, short-term preservation during workshops can be done at 2-4oC.
Confidentiality should be respected at each and every step. No part of body can be transported outside the laboratory without appropriate official clearances. Identification can be limited to age, sex, date, and cause of death written on a wrist or armband. At any time, photograph of cadaver, face, or tattoo should not be taken except for learning purposes, the face is draped all the time.
Disposal of cadaver remains is done as per religious belief last known. Cadaver and human anatomical remains fall under biomedical waste category which should be disposed in accordance with "Biomedical Waste Rules, 1998". Incineration and deep burial are the disposal options for human anatomical waste, which includes cadavers and the waste after dissection and research. Deep burial can be an option in towns with population less than five lakhs. The standards of deep burial instructs burial in a two meters deep trench, half filled with waste and covered with lime.  However, in few countries, for willed donors there are options for sending remains to kins as per consent of the donor. 
Cadaver dissection laboratory needs a proper infrastructure right from cadaver procurement to its disposal. The majority of this is done in the Department of Anatomy and Forensic Medicine. Dedicated surgical dissection is performed in Neurosurgery Cadaver Dissection Laboratory, which should be well-equipped with microscopic and endoscopic neurosurgery equipment and instruments.
Running a neurosurgical cadaver dissection laboratory is teamwork, which needs manpower with full time dedication. Laboratory technician and assistant should be charged with record keeping and maintenance of the laboratory. An experienced research fellow in Neurosurgery is of immense help in cadaver dissection and research projects.
The laboratory should have a well-lit ventilated room with a table for dissection and procedure demonstration. Disarticulated heads are usually sufficient for cranial neurosurgery procedures. Head is fixed on pin based head holders or Mayfield or Sugita head frames. All cranial procedures can be easily practiced over cadavers except for endoscopic ventricular procedures, as there is loss of cerebrospinal fluid (CSF) due to autocatalytic effects of the brain leading to loss of turgor. Tubbs et al., have demonstrated a technique of injecting saline and air into lateral ventricle, which leads to ventricular wall expansion.  With this upcoming technique, even ventricular procedures would be possible in the near future. Especially important are visualization of cerebrovascular architecture which is possible with silicone injection into major arterial and venous system in the head. At few centers, pumped systems are used which allow for pulsations in the brain that produce the feel of normal pulsations. ,
Cadaver labs can be categorized into basic and advanced facility as per the complexity of the approaches practiced. Basic laboratory can be established with operating microscope, micro-neurosurgery instrument set, high-speed drill set, and recording facilities for performing basic neurosurgical procedures including skull base approaches. Advanced laboratories need additional neuro-endoscopy set with imaging modalities (such as C-arm) for neuro-endoscopic and spine instrumentation practices.
A good quality microscope is necessary to practice minutiaes of micro-neurosurgical procedures. Ideally, the microscope should have facilities for magnification and focusing. It is of utmost importance to practice under microscope as shifting from gross to microscopic neurosurgery is difficult not only for novice but also for a trained neurosurgeon. This leads to a complete change of habitat; as the instruments move faster, field of view is multiple times magnified, only tip of the instruments are seen and tremors are more apparent. Only a dedicated and structured practice under microscope can get translated to efficient performance inside OR. It is also found complementary to endoscopic neurosurgery. NETS, AIIMS is equipped with operating microscopes with video recording facility for later evaluation (both, self and expert). 3-dimensional (3D/HD) microscope has been installed for the effectual training allowing the depth perception for viewers and recording [Figure 3].
Microsurgery instrument set
No cadaver surgery can be performed proficiently without proper microsurgical instruments, which involves all routinely used instruments in the Neurosurgery OR [Table 1]. High-speed drill machine and suction machine are indispensable components; appropriate electrical or pneumatic high-speed drill machine with drill bits comprising of cutting and diamond drills [Figure 4]. For laboratory practices, electric drill is preferred for its low maintenance cost and space requirement. As cadaver dissection is a blood-less surgery, cautery is not required.
Endoscopy instrument set
Endoscopic surgical procedures are further complicated, as there is loss of third dimension of vision; surgeries are performed at a distance looking at the monitor and ergonomics are changed.  This needs a complete new way of training demanding a whole neuro-endoscopy armamentarium, comprising of different angled scopes (0, 30, 45 degrees), light source, endoscopic camera, monitor and basic surgical instruments such as grasper, scissors, and knife , [Table 1].
The angle of scope is guided by the surgical intent. For novice, the first important step of endoscopic neurosurgery is to learn the anatomy from endoscopic perspective. Neuro-endoscopy skills training need a separate cadaver dissection lab [Figure 5]. One should learn to identify the important surgical landmarks and depth perception with two dimensions of vision. Most of the endoscopic surgical procedures and inspection can be performed with zero degree scope only. However, 30, 45, and 70 degree scopes are usually used for inspection only; there is significant change in anatomy viewpoint. 45 and 70 degree scopes are especially useful for endoscope assisted micro-neurosurgery. Such scopes are used only for rostral lesions such as cribriform plate or frontal sinus. Most scopes are rigid endoscopes with 18-20 cm in length and 4 mm in diameter. Flexible endoscopes are less popular because of inferior quality of images [Table 1].
The light sources can be xenonor halogen. The most commonly used one is xenon 300 light sources, which produces chromatic effects close to sunlight. At NETS, we use Halogen and Xenon 300 cold light chain system.
The cameras used are single chip (horizontal separation >450 lines) or three chip (horizontal separation >750 lines) Charge-Coupled Device (CCD) cameras. Three chip cameras are preferred for their superior image quality, resolution and color combinations.
Three-chip camera has red, green, and blue (RGB) input, and is identical to the color cameras used for television production. RGB imaging provides the highest fidelity, but is probably not necessary for everyday use. Digital enhancement detects edges and areas, where there are drastic color or light changes between two adjacent pixels. By enhancing this difference, the image appears sharper and surgical resolution is improved. Digital enhancement is available on one- and three-chip cameras. A high definition (HD) monitor is required for proper visualization. The quality of video and image is of utmost importance for research purposes, so should be checked and stored properly.
Video recording and storage devices
All cadaveric work should be properly recorded for self and expert evaluation. Videos should be recorded on at least 1920 × 1080 pixels resolution for clear anatomic features. These should be stored in the form of compact discs or external hard discs. At NETS, we use Unix Macintosh based iMac system with 'Final Cut Studio' editing software for video recording and external hard discs for their storage for later evaluation or processing.
Cadaver laboratory decorum
The trainees should practice universal precautions all the times. One should be scrubbed with gloves, full shoes, cap and goggles. They should respect the cadaver as their true patients and try to do the procedure as if conducting over a patient with utmost care to maximize their learning.
The trainees should come prepared reading about procedures thoroughly and doing the cognitive rehearsals prior to cadaver dissection. Ideally, there should be two trainees and one faculty in one station. It should start early in the day with one didactic lecture followed by demonstration by the faculty, so that trainees get enough time to practice. One procedure has to be divided in to multiple stages. The trainee has to follow faculty after each stage under supervision and should not proceed unless he has completed that step properly. The trainees should be dedicated and take time in each step rather than being in a hurry and interrupt the learning environment. In case of lack of number of cadavers, the faculty can demonstrate and the trainees can have the visual and tactile observation without the freedom of manipulation.
The dissection procedure may be used for both teaching and research. All research works should be based on strict pre-procedure protocol. The protocol should be well discussed and curriculum-based justifying the aims and objectives of the study, completion time and expected expenditure. At NETS, AIIMS, New Delhi, routine training sessions for neurosurgical procedures are performed for anatomic simulation and hands on practice [Table 2].
Advances in cadaver dissection
The traditional cadaver dissection is very beneficial for microscopic and endoscopic neurosurgical practice. But, it lacks in a few aspects such as bloodless field, collapsed ventricles etc., Injection of colored silicon or epoxy-resins for vein and arteries during preparation phase provides better anatomical view during cadaveric procedures. The internal carotid artery and the jugular vein are cannulated, and all the blood clots are cleared by irrigation followed by sequential injection with colored silicon or resins at particular pressure. , Apart from this, stereotactic and robotic neurosurgery can also be practiced on cadavers.  To simulate tumor in the cadaver brain, Strata thane resin ST-504 polymer (SRSP) developed by nanotechnology, may be injected that creates and exhibits properties of an extra axial tumor. It has a distinct Computed Tomography and Magnetic Resonance Imaging characteristics that simulates the preoperative planning of the real procedure. 
No war can be won without proper resources. Running a neurosurgical cadaver laboratory needs lot of capital investment right from its inception to maintenance. This includes salary of concerned personnel, regular purchase and maintenance of instruments and OR goods [Table 3]. The basic surgical set like microscope, endoscope and drill machines are quite expensive. Industrial support is desired for research purpose to provide old instruments free or at subsidized rate. At government institutional level, such support might be obtained from funding agencies such as ICMR, Department of Science and Technology (DST), Department of Biotechnology (DBT) and Department of Health Resources (DHR) etc.
It is beyond doubt that cadavers help in understanding and developing the craft of surgery. High-end surgical branches, such as neurosurgery are always at the mercy of their practitioners for this craft. A cadaver laboratory is a place where beginners develop and practitioners master surgical techniques. Establishment of more such laboratories in India at different geographical locations will help in knowledge dispersion and skills acquisition without travelling long distances. Practical pitfalls and technical guidelines are crucial for establishment and maintenance of the laboratory. Last but not the least, medical science will always owe the worthy souls, whose bodies have been used for training and research purposes.
We give our sincere thanks to Prof. PN Tandon, Prof. AK Banerjee, Prof. VS Mehta and Prof AK Mahapatra for their untiring efforts and guidance in establishing this laboratory. We would like to acknowledge the efforts of technical and application specialists from Neurosurgery Skills Training Facility, Neurosurgery Education and Training School, All India Institute of Medical Sciences, New Delhi, India. We thank Miss Payal Jotwani, Miss Britty Baby, Mr. Vinkle Srivastava, Mr. Ramandeep Singh, Mr. Subhas Bora, Mr. Ajab Singh, Mr. Ram Niwas, Mr. Shashi Shekhar, Mr. Trivendra Yadav, Mr. Aakash Sharma, Mr. Gaurav Bharadwaj, Mr. Suresh Kothari, Mr. Vikram Singh, Mr. Satish Kumar for their untiring valuable support.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]