Virtual simulator as a training tool for endonasal surgery

BACKGROUND: Virtual simulation could be an important tool for medical and surgical training as well as education. The efficacy of a simulator for endoscopic nasal procedures in a training program was evaluated. METHODS: The simulator is a medical and scientific tool for visualizing and interacting with three-dimensional volumetric data. Twenty endonasal operations with chronic rhinosinusitis were simulated by two 3rd-year residents and proctored by the senior surgeon 1 day before the actual surgery was performed with an endoscope and computer-aided surgery. A questionnaire was established. RESULTS: The surgical simulator may provide a better understanding of the morphology of the paranasal sinuses with a minor impact on performance of endoscopy by junior residents. Disadvantages identified were time consumption, absence of force feedback, and subtle handling of the joysticks. CONCLUSION: The virtual simulator allows the nonendoscopically nasal trained surgeon to understand and practice endonasal surgery using real-patient data but failed to make an impact on operating room performance. Furthermore, the simulator's effectiveness was limited by the absence of force feedback, subtle handling of the joysticks, and considerable time consumption.     

Learning curves, acquisition, and retention of skills trained with the endoscopic sinus surgery simulator

BACKGROUND: As an initial step in evaluating the effectiveness of training otolaryngology residents on an endoscopic sinus surgery simulator (ES3), we have assessed the ability of the ES3 to train persons inexperienced in sinus surgery (medical students) to perform certain simulated procedural tasks needed in endoscopic sinus surgery (ESS). METHODS: A total of 26 medical students were enrolled and trained on the ES3 following a preset protocol in the three levels of difficulty and complexity (novice, intermediate, and advanced modes). RESULTS: In the novice mode (three-dimensional abstract images are used to teach the use of endoscopic surgical equipment), medical students displayed a steep learning curve within three to five trials on the simulator and after an additional four to five trials, they reached a plateau in their learning curves to within 90% of that of experienced sinus surgeons. In the intermediate mode (ESS is performed on a simulated patient with teaching aids), medical students were able to reach a plateau in their learning curves to within 80% of that of experienced surgeons. This performance was sustained in the advanced mode (simulated sinus surgery without teaching aids). We observed that medical students, who had novice or intermediate mode training interrupted with an interval of 11-60 days, were able to resume their training without deviation from their prior learning curves. CONCLUSION: Intensive, proctored training on the ES3 can train inexperienced persons to perform simulated ESS within a reasonable approximation of the performance of experienced sinus surgeons on the ES3 and the training that an inexperienced person receives on the simulator is not short term but is retained over a period of at least 2 months.     

Traditional endonasal and microscopic sinus surgery complications versus endoscopic sinus surgery complications: a meta-analysis

The aim of this study was to compare the incidence of complications of endoscopic sinus surgery (ESS) to the incidence of complications of traditional and microscopic sinus surgery. A meta-analysis was carried out on 28 series of patients (a total of 13,405) who had undergone ESS, 8 series of patients (3,887 in total) who had undergone traditional endonasal sinus surgery and 7 series of patients (1,630 in total) who had undergone microscopic sinus surgery. The authors used the Bayesian inference package WinBUGS operating from within the statistical computer program R (version 2.7.1). Major complications had a higher incidence after traditional sinus surgery than ESS but this fact did not cause a significant statistical difference, whereas microscopic surgery had significantly more complications than ESS (p < 0.05). Carrying out our meta-analytic study, comparing major and minor complications of endonasal surgical approaches, was very difficult due to several methodological biases of data extraction and evaluation from studies concerning a broad timespan. Regarding major complications, we only found a significant statistical difference (p < 0.05) between the endoscopic (1%) and the microscopic methods (2.0%), but, if we had analyzed the data considering the natural learning curve of the latest ESS surgical approach, and if we had not considered the results produced in the first 10 years (1988–1998) concerning ESS in our meta-analysis, we would have found a statistically significant difference (p < 0.05) between the endoscopic (0.4%) and the traditional (1.1%) approach as well.     

Functional endoscopic sinus surgery training simulator

Objective/Hypothesis: To determine the efficacy of a haptic (force feedback) device and to compare isosurface and volumetric models of a functional endoscopic sinus surgery (FESS) training simulator. Study Design: A pilot study involving faculty and residents from the Department of Otolaryngology at The Ohio State University. Methods: Objective trials evaluated the haptic device's ability to perceive three-dimensional shapes (stereognosis) without the aid of image visualization. Ethmoidectomy tasks were performed with both isosurface and volumetric FESS simulators, and surveys compared the two models. Results: The haptic device was 77% effective for stereognosis tasks. There was a preference toward the isosurface model over the volumetric model in terms of visual representation, comfort, haptic-visual fidelity, and overall performance. Conclusions: The FESS simulator uses both visual and haptic feedback to create a virtual reality environment to teach paranasal sinus anatomy and basic endoscopic sinus surgery techniques to ear, nose, and throat residents. The results of the current study showed that the haptic device was accurate in and of itself, within its current physical limitations, and that the isosurface-based simulator was preferred. Laryngoscope, 108:1643–1647, 1998     

An anatomically sound surgical simulation model for myringotomy and tympanostomy tube insertion

Objective

Myringotomy and tympanostomy tube insertion (MT) is a common surgical procedure. Although surgical simulation has proven to be an effective training tool, an anatomically sound simulation model for MT is lacking. We developed such a model and assessed its impact on the operating room performance of senior medical students.

Study design

Prospective randomized trial.

Methods

A randomized single-blind controlled study of simulation training with the MT model versus no simulation training. Each participant was randomized to either the simulation model group or control group, after performing an initial MT procedure. Within two weeks of the first procedure, the students performed a second MT. All procedures were performed on real patients and rated with a Global Rating Scale by two attending otolaryngologists. Time to complete the MT was also recorded.

Results

Twenty-four senior medical students were enrolled. Control and intervention groups did not differ at baseline on their Global Rating Scale score or time to complete the MT procedure. Following simulation training, the study group received significantly higher scores (P = .005) and performed the MT procedure in significantly less time (P = .034). The control group did not improve their performance scores (P > .05) or the time to complete the procedure (P > .05).

Conclusion

Our surgical simulation model shows promise for being a valuable teaching tool for MT for senior medical students. Such anatomically appropriate physical simulators may benefit teaching of junior trainees.     

Construct validity of the endoscopic sinus surgery simulator: II. Assessment of discriminant validity and expert benchmarking

OBJECTIVES: To establish discriminant validity of the endoscopic sinus surgery simulator (ES3) (Lockheed Martin, Akron, Ohio) between various health care provider experience levels and to define benchmarking criteria for skills assessment. DESIGN: Prospective multi-institutional comparison study. SETTING: University-based tertiary care institution. PARTICIPANTS: Ten expert otolaryngologists, 14 otolaryngology residents, and 10 medical students. INTERVENTIONS: Subjects completed the ES3's virtual reality curriculum (10 novice mode, 10 intermediate mode, and 3 advanced mode trials). Performance scores were recorded on each trial. Performance differences were analyzed using analysis of variance for repeated measures (experience level as between-subjects factor). MAIN OUTCOME MEASURES: Simulator performance scores, accuracy, time to completion, and hazard disruption. RESULTS: The novice mode accurately distinguished the 3 groups, particularly at the onset of training (mean scores: senior otolaryngologists, 66.0; residents, 42.7; students, 18.3; for the paired comparisons between groups 1 and 2 and groups 1 and 3, P = .04 and .03, respectively). Subjects were not distinguished beyond trial 5. The intermediate mode only discriminated students from other subjects (P = .008). The advanced mode did not show performance differences between groups. Scores on the novice mode predicted those on the intermediate mode, which predicted advanced mode scores (r = 0.687), but no relationship was found between novice and advanced scores. All groups performed equally well and with comparable consistency at the outset of training. Expert scores were used to define benchmark criteria of optimal performance. CONCLUSIONS: This study completes the construct validity assessment of the ES3 by demonstrating its discriminant capabilities. It establishes expert surgeon benchmark performance criteria and shows that the ES3 can train novice subjects to attain those. The refined analysis of trial performance scores could serve educational and skills assessment purposes. Current studies are evaluating the transfer of surgical skills acquired on the ES3 to the operating room (predictive validity).     

3D-printed pediatric endoscopic ear surgery simulator for surgical training

IntroductionSurgical simulators are designed to improve operative skills and patient safety. Transcanal Endoscopic Ear Surgery (TEES) is a relatively new surgical approach with a slow learning curve due to one-handed dissection. A reusable and customizable 3-dimensional (3D)-printed endoscopic ear surgery simulator may facilitate the development of surgical skills with high fidelity and low cost. Herein, we aim to design, fabricate, and test a low-cost and reusable 3D-printed TEES simulator.MethodsThe TEES simulator was designed in computer-aided design (CAD) software using anatomic measurements taken from anthropometric studies. Cross sections from external auditory canal samples were traced as vectors and serially combined into a mesh construct. A modified tympanic cavity with a modular testing platform for simulator tasks was incorporated. Components were fabricated using calcium sulfate hemihydrate powder and multiple colored infiltrants via a commercial inkjet 3D-printing service.ResultsAll components of a left-sided ear were printed to scale. Six right-handed trainees completed three trials each. Mean trial time (n = 3) ranged from 23.03 to 62.77 s using the dominant hand for all dissection. Statistically significant differences between first and last completion time with the dominant hand (p < 0.05) and average completion time for junior and senior residents (p < 0.05) suggest construct validity.ConclusionsA 3D-printed simulator is feasible for TEES simulation. Otolaryngology training programs with access to a 3D printer may readily fabricate a TEES simulator, resulting in inexpensive yet high-fidelity surgical simulation.     

A preliminary randomised controlled trial evaluating the efficacy of saline douching following endoscopic sinus surgery

Objective: To assess whether saline reduces postoperative signs following endoscopic sinus surgery (ESS). Design: Within subject, single blinded randomised controlled trial. Setting: Single secondary referral centre. Participants: Adults undergoing bilateral ESS for chronic rhinosinusitis or nasal polyposis. Intervention: Saline douching of one side of the nasal cavity, three times per day for 6 weeks. Main outcome measures: Presence of adhesions, polyps, crusting, discharge or oedema under endoscopic examination at 3 weeks and 3 months postoperative. Results: Twenty‐three patients were recruited. Attendance was 22 patients at 3 weeks and 17 patients at 3 months. At 3 weeks saline douching significantly improved the presence of discharge (P = 0.046) and non‐significantly improved the presence of oedema (P = 0.059) with minimal difference with regard to polyps (P = 0.32) and no difference with adhesions or crusting. At 3 months there was minimal difference with regard to crusting (P = 0.18) and oedema (P = 0.32) and no difference with adhesions, discharge and polyps. Conclusions: Saline douching reduces nasal discharge and may improve oedema during the healing phase following ESS which may represent a possible anti‐inflammatory role. No long‐term effect was found.     

Computer-aided endoscopic sinus surgery

Objectives: To examine four different types of computer-aided endoscopic sinus surgical devices—the ISG Viewing Wand, the ISG infrared OptoTrak, the IGT FlashPoint 5000, and the VTI InstaTrak—with emphasis on their accuracy and ease of use. Study Design: Prospective study utilizing laboratory experiments and intraoperative data collection. Methods: A review of the literature is presented. Patients undergoing endoscopic sinus surgery during the study period were enlisted under FDA protocols with IRB consent. Groups of patients had surgery performed with each of the above devices—except the FlashPoint 5000. Accuracy measurements were recorded, and user and operating staff comments about ease of use were collected. The FlashPoint 5000 was used exclusively in the laboratory setting, where accuracy measurements were obtained on a cadaver skull. Results: The systems all demonstrated accuracy to within 2.00 mm. Ease of use was somewhat variable, but following a learning curve by the surgeon and operating department personnel, all of the units were considered to be relatively user friendly. Conclusions: Computer-aided endoscopic sinus surgery appears to be the wave of the future. Nevertheless, the modern endoscopic sinus surgeon must have thorough training in the basic anatomy of the paranasal sinuses as well as the various surgical techniques.     

Safety of endoscopic sinus surgery in a residency training program

Over the past decade, endoscopic sinus surgery has become one of the most frequently performed operations in otolaryngology. Nevertheless, concerns have been raised about the safety of this procedure in a residency training program. To address this issue, we carried out a retrospective review to assess the complications of endoscopic sinus surgery performed by otolaryngology residents under close supervision. We reviewed the medical records of 597 patients who had undergone 719 operations performed by residents in the Department of Otolaryngology-Head and Neck Surgery of the University of Southern California-Los Angeles County Medical Center and at the University Hospital between June 1988 and December 1995. Most of these procedures were performed by junior residents under the supervision of either a senior resident or faculty member. We found that the incidence of minor and major complications was 12.2 and 0.4%, respectively. The most common minor complications were vascular. The only major complication was excessive bleeding that required transfusion. There were no cases of blindness, cerebrospinal fluid rhinorrhea, or death. We conclude that endoscopic sinus surgery in an otolaryngology residency training program is a relatively safe procedure, especially when performed under faculty supervision.     

Wound healing in endoscopic sinus surgery: Phase 1 clinical trial evaluating the role of Chitogel with adjuvants

Objectives

This study aimed to determine the safety and efficacy of Chitogel, with and without Deferiprone (Def) and Gallium Protoporphyrin (GaPP), as a promoter of wound healing to improve surgical outcomes after endoscopic sinus susgery.

Design

A double-blinded, randomised control human clinical trial was conducted in patients undergoing ESS as a treatment for chronic rhinosinusitis. Participants underwent functional ESS or FESS with drill out as required and were randomised to receive test product Chitogel, Chitogel in combination with Def or Def-GaPP versus no packing (control).

Setting

Ostial stenosis and persistent inflammation are the main reasons for revision endoscopic sinus surgery (ESS). Post-operative (PO) dressings can improve PO wound healing and patient outcomes after ESS.

Participants

Eighty two patients were included in this study with 79 patients completing the study with 40 undergoing full house FESS and 39 FESS plus frontal drillout.

Main Outcome Measures

Patients were followed up at 2, 6 and 12 weeks PO, and outcome scores such as SNOT-22, VAS and LKS, pre and post-surgery (12 weeks) were compared.

Results

Seventy nine patients completed the study, there was a significant reduction in SNOT-22 score and improvement of VAS at 12 weeks in patients treated with Chitogel compared to control (p < .05). In those patients, the mean ostium area for the Chitogel and the Chitogel + Def + GaPP groups was higher across all three sinuses compared to the no-treatment control group, without statistical significance. Sphenoid sinus ostium was significantly more patent in patients treated with Chitogel compared to the control at the 12-week time point (p < .05).

Conclusion

Chitogel as a PO dressing after ESS results in the best patient-reported symptom scores and objective measurements. The combination of Def and GaPP to Chitogel though proving safe, had no effect on the ostium patency or mucosal healing.     

Shortcomings of lateral sinus radiograph in the preoperative determination of the extent of endonasal endoscopic sinus surgery

Lateral sinus radiograph is helpful in determining the distances between certain anatomic landmarks in preparation for endonasal endoscopic sinus surgery. However, some misleading factors limit the usefulness of this radiograph. In this study these distances were measured in 49 patients and compared with measurements obtained from another imaging modality, magnetic resonance imaging, which provides more accurate measurements. Results show a discrepancy in the measurements of distances between some of these landmarks that cannot be explained by the factor of magnification alone on the sinus radiographs. Statistical analysis of the results for women revealed a significant discrepancy between the distances from the nasal spine to the midfovea ethmoidalis, the sphenoethmoid junction, and the posterior sphenoid wall as measured on MR images and those as measured on lateral sinus radiographs (P<.05). For men the same was true for the distances from the nasal spine to the midfovea ethmoidalis and the posterior sphenoid wall (P<.05). It is concluded that there should be reservations in the surgical application of data provided by the lateral sinus radiograph before endoscopic sinus surgery.     

Validation of the Modena bleeding score in endoscopic sinus surgery

IntroductionThe Modena bleeding score is a categorical rating scale that allows the assessment of the surgical field in relation to bleeding during endoscopic surgery. It has recently been presented and validated in the field of endoscopic ear surgery by the present authors. The Modena bleeding score provides five grades for rating the surgical field during endoscopic procedures (from grade 1 ? no bleeding to grade 5 ? bleeding that prevents every surgical procedure except those dedicated to bleeding control).ObjectiveThe aim of this study was to validate the Modena bleeding score in the setting of endoscopic sinus surgery.MethodsFifteen three-minute videos of endoscopic sinus surgery procedures (each containing three bleeding situations) were evaluated by 15 specialists, using the Modena bleeding score. Intra and inter-rater reliability were assessed, and the clinical validity of the Modena bleeding score was calculated using a referent standard.ResultsThe data analysis showed an intra-rater reliability ranging from 0.6336 to 0.861. The inter-rater reliability ranged from 0.676 to 0.844. The clinical validity was α = 0.70; confidence limits: 0.64 ? 0.75, corresponding to substantial agreement.ConclusionThe Modena bleeding score is an effective method to score bleeding during endoscopic sinus surgery. Its application in future research could facilitate the performance and efficacy assessment of surgical techniques, materials or devices aimed to bleeding control during endoscopic sinus surgery.     

Supporting skill acquisition in cochlear implant surgery through virtual reality simulation

Objectives: To evaluate the effectiveness of a virtual reality (VR) temporal bone simulator in training cochlear implant surgery.

Methods: We compared the performance of 12 otolaryngology registrars conducting simulated cochlear implant surgery before (pre-test) and after (post-tests) receiving training on a VR temporal bone surgery simulator with automated performance feedback. The post-test tasks were two temporal bones, one that was a mirror image of the temporal bone used as a pre-test and the other, a novel temporal bone. Participant performances were assessed by an otologist with a validated cochlear implant competency assessment tool. Structural damage was derived from an automatically generated simulator metric and compared between time points.

Results: Wilcoxon signed-rank test showed that there was a significant improvement with a large effect size in the total performance scores between the pre-test (PT) and both the first and second post-tests (PT1, PT2) (PT-PT1: P?=?0.007, r?=?0.78, PT-PT2: P?=?0.005, r?=?0.82).

Conclusion: The results of the study indicate that VR simulation with automated guidance can effectively be used to train surgeons in training complex temporal bone surgeries such as cochlear implantation.     

Endoscopic sinus surgery: A safe procedure among the less experienced surgeons?

Objectives

To determine the incidence of complications in endoscopic sinus surgery (ESS), in a surgical centre with 20 years of experience, and whether or not the surgeon's experience can be a predisposing factor for them to happen.

Methods

The clinical data of the 667 patients who were submitted to EES between January of 2006 and December 2009, was reviewed, and the perioperative and postoperative complications were evaluated, with a minimum follow up period of 3 months. For each surgery, the surgeon's experience as well as surgery particularities, were correlated with the presence of complications.

Results

In the 677 surgeries, the incidence of complications was of 7.39% (5.91% minor and 1.48% major). There was no correlation between surgery complications and the years of experience of the main surgeon. When comparing the complication rate between residents and specialists, there were no statistically significant differences between them. Extensive surgeries, revision surgeries and the presence and grade of polyposis, were associated with a higher rate of complications.

Conclusions

ESS is not a risk free procedure. Complications can happen regardless of the surgeońs experience. Patients who are submitted to surgery by residents, under the supervision of a senior doctor, are not at greater risks of complications.     

Audit‐derived guidelines for training in endoscopic sinonasal surgery (ESS) – protecting patients during the learning curve

The objective of the present study is to propose guidelines to ensure safe practice in teaching centres while allowing endoscopic sinonasal surgery (ESS) training to proceed. A prospective complications audit of ESS procedures was undertaken over a 5‐year period (January 1996–December 2000). The results have been used to form specific guidelines for safe and effective ESS training. A total of 500 patients underwent ESS during the 5‐year period. The senior author was the main surgeon in 55% of cases with the trainee observing or assisting. A supervised trainee was the main surgeon in 45% of cases. The overall complication rate was 1.2% (n = 6) (i.e. 0.7% for the 815 procedures performed). These were all minor complications. We encountered no major complications in 500 patients over the 5‐year period. This audit shows that training need not compromise patient safety provided it is phased and structured. We propose appropriate phases and suggest the minimum requirements for units involved in ESS training.     

Endoscopic sinus surgery checklist

Over 250,000 endoscopic sinus surgeries are performed yearly in the United States alone. Although overall complication rates are low, errors can lead to significant morbidity due to the close proximity of the sinuses to the orbit and skull base and the resultant potential for blindness, cerebrospinal fluid leak, and catastrophic bleeding. Surgical checklists are endorsed by the World Health Organization and have been incorporated into most U.S. operating rooms as a measure to minimize avoidable errors. Standardized surgical checklists were developed with general and/or orthopedic procedures in mind, but in many instances they fail to incorporate concerns specific to endoscopic sinus surgery (ESS). In response to this clinical problem, we sought to develop and institute an ESS surgical checklist. This checklist can serve as a template for physicians who perform ESS and wish to prevent avoidable adverse events.     

Comparison of direct monocular endoscopic,two- and three-dimensional display systems on surgical task performance in functional endoscopic sinus surgery

Surgeons performing functional endoscopic sinus surgery (FESS) traditionally rely on direct endoscopic viewing through a single monocular Hopkins rod lens telescope. While the majority of surgeons have found this satisfactory, most other endoscopic surgical specialities have moved to 2-D video endoscopy, where a monoscopic image is presented on a television monitor. This study set out to determine whether 2-D or 3-D display systems had any advantage over direct endoscopy in FESS. Ten otolaryngology trainees performed a series of standardized procedures on a FESS model using direct endoscopic vision, 2-D and 3-D. A performance score was obtained by dividing the execution time by the number of tasks achieved. There was a significant difference in both surgical and diagnostic task performance with 2-D (mean scores 56.8 and 41.1) performing better than direct endoscopy (mean scores 94.1 and 74.1) (P < 0.05). Tasks were also performed significantly better with 3-D compared with 2-D (P < 0.05).     

Diplopia secondary to endoscopic sinus surgery

Objective—Diplopia after endoscopic sinus surgery (ESS) is rare but very serious. In this study, we investigated the characteristics, prognosis and treatment of diplopia occurring after ESS.

Material and Methods—A retrospective analysis was carried out to investigate three patients with diplopia after ESS referred to us from other hospitals.

Results—In one case, an improvement in ocular motility was seen after surgical treatment. In the other cases, no improvement was observed, despite surgical treatment.

Conclusion—In order to prevent diplopia after ESS, the surgeon must possess a complete anatomical knowledge obtained by means of cadaveric dissection, the ability to carefully read preoperative CT scans and the necessary surgical experience.     

Comparison of direct monocular endoscopic,two- and three-dimensional display systems on surgical task performance in functional endoscopic sinus surgery

The operating endoscope has been an important advance in nasal and sinus surgery. Most surgeons describing the technique have used direct monocular vision, though some have recently been using videoendoscopic technology. Video monitoring offers the possibility of bimanual instrument handling and 3D visualization, with the appropriate equipment. We performed a study involving 10 surgeons, in which performance in simulated FESS was evaluated for direct endoscopic vision and compared with 2D and 3D video monitor display systems. There was a statistically significant difference in task performance time (visualizing or removing three small rings placed in the nasal cavity) between the three techniques. The direct technique was performed most slowly, participants taking longer with this technique than with the other two to perform the tasks. The 2D technique was more rapid, with the 3D technique taking the shortest time (P < 0.05). We feel that there is a place for further evaluation of video monitor controlled endoscopic sinus surgery.