Rajagopalan Raman

Injecting Realism in Surgical Training—Initial Simulation Experience With Custom 3D Models

UNLABELLED The traditionally accepted form of training is direct supervision by an expert; however, modern trends in medicine have made this progressively more difficult to achieve. A 3-dimensional printer makes it possible to convert patients imaging data into accurate models, thus allowing the possibility to reproduce models with pathology. This enables a large number of trainees to be trained simultaneously using realistic models simulating actual neurosurgical procedures. The aim of this study was to assess the usefulness of these models in training surgeons to perform standard procedures that require complex techniques and equipment. METHODS Multiple models of the head of a patient with a deep-seated small thalamic lesion were created based on his computed tomography and magnetic resonance imaging data. A workshop was conducted using these models of the head as a teaching tool. The surgical trainees were assessed for successful performance of the procedure as well as the duration of time and number of attempts taken to learn them. FINDINGS All surgical candidates were able to learn the basics of the surgical procedure taught in the workshop. The number of attempts and time taken reflected the seniority and previous experience of each candidate. DISCUSSION Surgical trainees need multiple attempts to learn essential procedures. The use of these models for surgical-training simulation allows trainees to practice these procedures repetitively in a safe environment until they can master it. This would theoretically shorten the learning curve while standardizing teaching and assessment techniques of these trainees.

The creation and verification of cranial models using three-dimensional rapid prototyping technology in field of transnasal sphenoid endoscopy.

BACKGROUND Surgical navigation systems have been used increasingly in guiding complex ear, nose, and throat surgery. Although these are helpful, they are only beneficial intraoperatively; thus, the novice surgeon will not have the preoperative training or exposure that can be vital in complex procedures. In addition, there is a lack of reliable models to give surgeons hands-on training in performing such procedures. METHODS A technique using an industrial rapid prototyping process by three-dimensional (3D) printing was developed, from which accurate spatial models of the nasal cavity, paranasal sinuses (sphenoid sinus in particular), and intrasellar/pituitary pathology were produced, according to the parameters of an individual patient. Image-guided surgical (IGS) techniques on two different platforms were used during endoscopic transsphenoidal surgery to test and validate the anatomical accuracy of the sinus models by comparing the models with radiological images of the patient on IGS. RESULTS It was possible to register, validate, and navigate accurately on these models using commonly available navigation stations, matching accurately the anatomy of the model to the IGS images. CONCLUSION These 3D models can be reliably used for teaching/training and preoperative planning purposes.Background Surgical navigation systems have been used increasingly in guiding complex ear, nose, and throat surgery. Although these are helpful, they are only beneficial intraoperatively; thus, the novice surgeon will not have the preoperative training or exposure that can be vital in complex procedures. In addition, there is a lack of reliable models to give surgeons hands-on training in performing such procedures. Methods A technique using an industrial rapid prototyping process by three-dimensional (3D) printing was developed, from which accurate spatial models of the nasal cavity, paranasal sinuses (sphenoid sinus in particular), and intrasellar/pituitary pathology were produced, according to the parameters of an individual patient. Image-guided surgical (IGS) techniques on two different platforms were used during endoscopic transsphenoidal surgery to test and validate the anatomical accuracy of the sinus models by comparing the models with radiological images of the patient on IGS. Results It was possible to register, validate, and navigate accurately on these models using commonly available navigation stations, matching accurately the anatomy of the model to the IGS images. Conclusion These 3D models can be reliably used for teaching/training and preoperative planning purposes.

Three-dimensional anatomical accuracy of cranial models created by rapid prototyping techniques validated using a neuronavigation station

In neurosurgery and ear, nose and throat surgery the application of computerised navigation systems for guiding operations has been expanding rapidly. However, suitable models to train surgeons in using navigation systems are not yet available. We have developed a technique using an industrial, rapid prototyping process from which accurate spatial models of the cranium, its contents and pathology can be reproduced for teaching. We were able to register, validate and navigate using these models with common available navigation systems such as the Medtronic StealthStation S7®.

Antibacterial and antifungal properties of human cerumen.

OBJECTIVE To assess the antibacterial and antifungal properties of human cerumen by studying its effect on the growth of Staphylococcus aureus, Esherichia coli, Pseudomonas aeruginosa and Candida albicans. MATERIALS AND METHODS Cerumen samples were collected from 75 normal, healthy subjects aged from seven to 80 years, without ear pathology, who attended the ear, nose and throat out-patient clinic of the University Malaya Medical Center from May 2006 to October 2006. Of these 75 samples, 31 had no growth when cultured on nutrient agar. Inhibition studies on these 31 samples were performed for Staphylococcus aureus (American Type Culture Collection (ATCC) 25923), Esherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Candida albicans. Nutrient agar was used to conserve all three bacterial strains and Sabouraud dextrose agar was used for Candida albicans. RESULTS A decrease in Staphylococcus aureus growth was observed for 27 of the 31 samples. All 31 samples induced decreased growth of Pseudomonas aeruginosa, while 29 induced decreased growth of Candida albicans. However, only four samples induced decreased growth of Escherichia coli. CONCLUSIONS Cerumen was demonstrated to have potential antimicrobial effects on strains of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans.

Ocular presentation of sphenoid mucocele

A sphenoid mucocele often presents late due to its deep-seated anatomical site. It has a varied presentation, due to its close relationship to the cavernous sinus and the base of the skull. It can present initially to the ophthalmologist with ocular complaints. In the present paper, the authors present two cases of sphenoid mucocele, one with an isolated third and one with an isolated sixth cranial nerve palsy.

Hypertensive retinopathy and sensorineural hearing loss

ObjectiveTo determine the correlation between hypertensive retinopathy (which is the end-organ damage of the vessels due to chronic hypertension) with sensorineural hearing loss.MethodsPure tone hearing threshold of 56 hypertensive patients were compared with 56 normal age and sex matched control. Comparisons of pure tone hearing threshold are made among different group (grade) of hypertensive retinopathy patients and control (non-hypertensive patients).ResultsThe mean hearing thresholds were higher (worse) in all the frequencies on both sides in the hypertensive study group compared with normal subjects. However it was found to be statistically significant when tested using independent sample test (p < 0.05) on right ear at 2,000 Hz, 4,000 Hz and 8,000 Hz only. The mean hearing threshold is higher in all frequencies in the presence of retinopathy compared to control. However, the difference was found to be only statistically significant in the mean hearing threshold between grade I and control at 4,000 Hz and 8,000 Hz on both sides and at 1,000 Hz and 2,000 Hz on right ear.Hypertensive patient with grade I retinopathy had higher pure tone hearing thresholds at 4,000 Hz and 8,000 Hz compared to hypertensive without retinopathy and normal control.ConclusionsHypertensive retinopathy appears to be associated with high frequency sensor neural hearing loss.

Study of epithelial migration in the tympanic membrane and bony external auditory canal wall in patients with irradiated nasopharyngeal carcinoma.

Objective The objectives of this study were to determine the presence of epithelial migration in patients with postirradiated nasopharyngeal carcinoma (NPC) and to compare the rate of epithelial migration in the tympanic membrane (TM) and the bony external auditory canal (EAC) of postirradiated NPC ears with normal ears by means of the ink dot method. Study Design Prospective, nonrandomized case-control study involving patients with NPC and control subjects with healthy ears seen in an otorhinolaryngology outpatient clinic. Setting Otorhinolaryngology Outpatient Clinic, University Malaya Medical Centre, Kuala Lumpur. Patients Patients with NPC who have completed radiotherapy and patients with normal ear presenting with other complaints. Intervention Patients who fulfilled the inclusion and exclusion criteria were chosen for this study. All the selected patients’ ears were visualized under a microscope and were cleaned, and ink dots were applied at the umbo and annulus. They were followed up on a 2- to 3-weekly basis until the ink dots reached the specified landmarks. The distance and pattern of migration were recorded and calculated. The mean radiation dose received by both the right and left TM and EAC was mapped and calculated. Main Outcome Measures Rate and pattern of epithelial migration in the NPC group compared with that in the control group. Results The mean radiation dose to both the TM and EAC did not show a significant difference (p > 0.05). The entire TM study group showed epithelial migration from the umbo toward the annulus and EAC, except in 1 ear. The mean rate of epithelial migration on the TM of the study group was 51.35 &mgr;m/d compared with that on the control group, which was 64.68 &mgr;m/d, and this difference was statistically significant (p < 0.05). Of the ears in the control group, 42.5% showed a migration pattern toward the posterior-superior direction, whereas 45% of the ears in the study group showed a migration pattern toward the posterior-inferior direction. In the EAC of the study group, the mean epithelial migration was noted to be accelerated compared to that of the control group (144.75 and 94.33 &mgr;m/d, respectively; p < 0.05). The mean rate of migration between the TM and the EAC was also different. Both the study and control groups showed a significant difference in migration, with a faster rate of migration in the EAC (p < 0.05). Conclusion We noted a significant delay in the rate of epithelial migration in the TM of patients with postirradiated NPC and an accelerated rate of migration in the EAC of patients with postirradiated NPC. In addition, epithelial migration in the EAC was also noted to be faster than that in the TM of the control population.

Comparison of the efficacy between oral rinse, oral gargle, and oral spray.

Introduction and Aims: Patients with sore throats are often treated with oral gargles or oral sprays. Some may rinse instead of gargle, leading to unsatisfactory outcome. The authors studied the efficacy of oral rinses, gargles, and sprays and the effect of Friedman palate position on the outcome. Methods: Ten subjects used specially prepared solutions to rinse, gargle, and then spray their oral cavities at 2-hour intervals. The blue dye indicated the areas stained by the solution, which were scored. Results: Although there was no difference in reaching the oropharynx between the gargles and sprays, they were both better than were the oral rinses (P < .001). The difference in Friedman palate position did not have an effect on the efficacy of the different modalities. Conclusion: Oral gargles and sprays have been shown to be significantly better than are oral rinses if the oropharynx is the targeted site, and the size of the oral airway does not impede their efficacy.

Suction Elevator for Ear Surgery

An instrument has been designed to combine a suction and an elevator for use in ear surgery.

An Alternate Approach to the Mastoid Antrum

An alternate approach to the mastoid antrum for acellular mastoid is presented.