Extraocular muscle surgery on goats' eye: An inexpensive technique to enhance residents' surgical skills

Quality assessment of polymer materials for human model eye development

PURPOSE

We developed model eyes using six polymer materials to determine which materials were most appropriate in simulating real human sclera and extraocular muscle (EOM).

METHODS

Five three-dimensional (3-D) printed polymers (FlexFill, PolyFlex, PCTPE, Soft PLA, and NinjaFlex) and one silicone material were systematically tested by board-certified ophthalmologists and senior ophthalmology residents. Material testing included scleral passes with 6-0 Vicryl sutures through each eye model. Participants completed a survey designed to collect demographic data, subjective assessment of each material's accuracy in simulating real human sclera and EOM, and a ranking for each polymer material to identify which would be most suitable for an ophthalmic surgery training tool. The Wilcoxon signed-rank test was conducted to determine if there was a statistically significant difference in the distribution of ranks between the polymer materials.

RESULTS

The distribution of ranks for silicone material's "sclera" and "EOM" components were statistically significantly higher than that of all other polymer materials (all p < 0.05). Silicone material received the highest rank for both "sclera" and "EOM" components. Survey results indicated that the silicone material effectively simulated real human tissue.

CONCLUSION

Silicone model eyes performed better than 3-D printed polymers as an educational tool for incorporation into a microsurgical training curriculum. Silicone models provide a low-cost teaching tool that allows for independent practice of microsurgical techniques without requiring a wet-laboratory facility.

Angle Examination Gonioscopy and Minimally Invasive Glaucoma Surgical Training on Human Eyes in Wet Lab

PURPOSE

To understand the feasibility, utility and efficacy of a low-cost model for performing anterior chamber angle gonioscopy and micro-surgery on human corneo-scleral tissues in wet lab on resident skill enhancement.

METHODS

Post-keratoplasty residual corneo-scleral rims and/or the expired donor corneo-scleral buttons were included for the purpose of this study. Initially, inverted rims were used to demonstrate the basic angle anatomy on a slit lamp bio-microscope. Central hazy cornea was then replaced with an artificial cornea and an artificial anterior chamber to simulate indirect gonioscopy, direct gonioscopy, goniotomy and other angle-based surgeries. Direct gonioscopy and goniotomy exercises (as a means to simulate intra-operative gonioscopy and other angle-based surgeries respectively) were evaluated quantitatively, and the rest qualitatively.

RESULTS

A total of 65 residents were included in the exercise. The mean age was 26.69±1.74 years. Amongst these, 55 ophthalmology residents performed the basic examination, that is, slit lamp mounted angle anatomy examination (n=55) and artificial chamber mounted indirect gonioscopic examination through artificial cornea (n=55). In the second exercise, 10 glaucoma fellows performed the direct gonioscopic and the goniotomy exercises on artificial chamber. The fellows demonstrated a statistically significant improvement in interpretation and surgical skill enhancement concurrent with reduction in time taken with increasing number of attempts (P<0.05). In the third simulation exercise, micro-stent placement within the Schlemm's canal, sub-conjunctival space, and the supra-choroidal space was re-produced successfully on multiple occasions.

CONCLUSIONS

The residual human corneo-scleral rims proved to be an important resource for teaching both the basic examination skills as well as those required for transitioning to advanced intraoperative gonioscopy and goniotomy skills. These low cost, easy to adapt models can be incorporated within the curriculum for improved glaucoma training of both the residents and the glaucoma fellows.

Simulation of complex strabismus surgical procedures on goat eyes

PURPOSE

To describe the possibility of complex strabismus surgical simulation on goat eyes.

METHODS

The goat eyes were procured from local slaughterhouse with retained extra ocular muscle tissues. The obtained eyes were inspected for globe integrity, muscle quality, muscle length, and the surrounding teno-conjunctival layers. The included eyes were then segregated for surgical simulation based on their insertion and orientation (as oblique or recti), and they were mounted on a mannequin head, with a fixation suture at free end to simulate the resting tension. Additionally, as per necessary, extra muscles were also transplanted along desired sites to simulate human extra ocular muscle anatomy.

RESULTS

The inferior oblique, superior oblique, and all other four recti were successfully simulated in varying proportions in more than 50 eyes. Primarily, by simulating the lateral rectus, inferior rectus, and the inferior oblique muscle, staged weakening procedures of inferior oblique were successfully practiced (Fink's recession, Park's recession, Elliot and Nankin procedure, total anterior positioning, and antero-nasal trans-position or Stager's procedure). Similarly, by simulating superior rectus, inferior rectus, lateral rectus, and the medial rectus muscles, half width transposition, full width transposition, and other complex procedures were practiced (Knapp's procedure, augmented Knapp's, Nishida's procedure, Faden operation, and Y splitting procedure). Furthermore, by simulating superior oblique and the superior rectus muscles, superior oblique tuck, posterior tenectomy, loop tenotomy, and Harada Ito procedures were successfully practiced.

CONCLUSIONS

On goat eyes, the complex strabismus surgical procedures can be successfully simulated and practiced after re-organizing the existing muscles in different patterns.

Evaluating the Efficacy of Microsurgical Training Methods in Ophthalmology Education: A Systematic Review and Meta-analysis

Objective  The objective of our paper is to review all of the relevant literature in ophthalmology microsurgical education and identify which teaching methodologies were most effective. Methods  A systematic review and meta-analysis of the literature was conducted. Electronic databases, including Ovid MEDLINE, Cochrane CENTRAL, and EMBASE, were searched with preset terms. The search was through December 11, 2019. Eligibility criteria included studies with sufficient data for analyzing associations between surgical teaching techniques and success rates in surgical skills and the organization of the intervention as a microsurgical skills course, curriculum, or program. The articles were independently reviewed by two authors. Each included study was evaluated for quality using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach and risk of bias using the Cochrane Collaboration's tool for assessing bias. Data Extraction and Synthesis  Data extraction was performed by two reviewers and disagreements were checked by a third reviewer. A random-effects analysis was used to pool the outcomes of studies. Main Outcomes and Measures  Outcomes included time for completion of surgical task, level of preparedness, competency score, and number of surgeries with complications. Results  A total of 439 studies were reviewed and 13 studies ( n  = 8,790 surgical cases; n  = 115 trainees) were included in the meta-analysis. Excluded articles studied cataract simulation training as the primary intervention or were not related to ophthalmology. All pooled results demonstrated a positive association with surgical outcomes; however, video-based education (standardized mean difference [SMD] = 2.49 [95% confidence interval (CI): 0.36-4.63]; four effects [four studies]; n  = 69; I 2  = 90%) and stepwise teaching method (odds ratio [OR = 3.84 [95% CI: 2.66-5.55]; six effects [six studies]; n  = 6,968; I 2  = 39%) interventions were the most favorable. Conclusion and Relevance  The following five interventions evaluated in this paper were found to be effective methods of improving performance outcomes in ophthalmic microsurgery: (1) didactic lectures, (2) video-based education, (3) surgical wet-laboratory, (4) stepwise method, and (5) direct supervision and feedback. Our meta-analysis concludes that video-based education and stepwise teaching interventions are the most effective methods for a microsurgical ophthalmology training curriculum. Combining the strengths of the interventions analyzed in this study should be considered when implementing and adjusting ophthalmic surgical skills curriculums.

Animal and cadaver human eyes for residents' surgical training in ophthalmology

In ophthalmology residency programs surgical training plays a vital role in creating confident and skillful surgeons. As almost all ophthalmic surgery needs microscope training, creating a well-taught environment for hand-eye coordination, ocular tissue handling, and anticipation of complications is essential. Wet lab training with animal or cadaver human eyes offers diverse possibilities. We conducted a thorough literature search on various databases to identify the existing literature on wet labs. The results revealed constructive efforts for training novice surgeons in all surgical ophthalmology subspecialties. Wet lab models were initially used only to practice cataract surgery; however, now various complex ocular procedures can be practiced. Ocular surface, corneal, iris, lenticular, scleral, vitreoretinal, extraocular, eyelid, and other adnexal surgeries were reproduced and mastered in many ways. Importantly, with repeated surgical practice, residents gained an increasing level of confidence with enhanced surgical accuracy. In addition, we propose a few novel techniques of various other procedures.

Oculoplastic surgical simulation using goat sockets

Purpose: To describe a reproducible and easily available goat socket model for training of various oculoplastic operations, and to evaluate trainees' perception of this training model in terms of their learning progress and satisfaction.Methods: Goat sockets including orbital rim and eye with eyelids were harvested in form of a split-head model. Ophthalmology residents underwent individual surgical training using the goat socket model, supervised by an oculoplastic attending. Participants completed a questionnaire in form of a 5-point Likert Scale to evaluate their learning progress and satisfaction.Outcome Measures: Types of oculoplastic operations performed using the goat socket models, and participants' rating of their learning progress and satisfaction were reported.Results: A wide range of oculoplastic operations including both eyelid and orbital operations could be simulated because of similarities of the goat eye model to the human eye anatomy. Fifteen ophthalmic trainees participated in surgical training using the goat eye model. All (100%) participants agreed that surgical simulation using the goat socket model increased their skills in surgical instrumentation and carrying out surgical steps, and their confidence in operating on patients. Most (87%) agreed the model resembled reasonably well compared to surgeries in human, and 93% would recommend training with the model to fellow resident ophthalmologists before operating on human patients.Conclusions: Oculoplastic surgical training using goat sockets is simple, readily available, and inexpensive. Trainee users showed promising feedback and positive learning progress using the goat socket model.

Trabeculectomy on Animal Eye Model for Resident Surgical Skill Training: The Need of the Hour

Purpose: To describe a goats' eye training model for teaching of trabeculectomy and releasable suture techniques for Ophthalmology residents. Methods: A descriptive report explaining the methodology for setting up a goats' eye wet-lab model for teaching trabeculectomy for Ophthalmology residents. It details the approaches to eyeball preparation, steps of surgery, application and release of two representative types of 'releasable sutures' in a step-by-step manner. Conclusion: A systematic approach using goats' eye model to teach trabeculectomy and releasable suture techniques can enhance residents' understanding, confidence and expertise to operate upon human eyes.