Development of a Simulation Surgical Cricothyroidotomy Curriculum for Novice Providers: A Learning Curve Study.

INTRODUCTION: Airway obstruction is the third most common cause of preventable death on the battlefield, accounting for 1%-2% of total combat fatalities. No previous surgical cricothyroidotomy (SC) studies have analyzed the learning curve required to obtain proficiency despite being studied in numerous other surgical technique training experiments. The aims of this study were to establish expert SC performance criteria, develop a novel standardized SC curriculum, and determine the necessary number of practice iterations required by a novice to reach this pre-determined performance goal. MATERIALS AND METHODS: A standardized checklist and SC performance standards were established based on the performance of 12 board certified Military Health System surgeons with prior experience on performing a SC using a simulated trauma mannequin. Expert-level criteria were defined as a SC time to completion of 40 s or less and checklist score of at least 9/10, including all critical steps. Study subjects included 89 novice providers (54 active-duty first- and second-year medical students and 35 Navy corpsmen). Subjects received instruction on performing a SC using the principles of mastery learning and performed a final test of SC proficiency on a trauma mannequin within a realistic simulated MEDEVAC helicopter. The total number of subject practice attempts, checklist scores, and time to completion were measured and/or blindly scored. Learning curve and exponential plateau equations were used to characterize their improvement in mean time to SC completion and checklist scores. RESULTS: Mean pre-test knowledge scores for the entire group were 11.8 ± 3.1 out of 24 points. Total mean practice learning plateaued at checklist scores of 9.9/10 after 7 iterations and at a mean completion time of 30.4 s after 10 iterations. During the final test performance in the helicopter, 67.4% of subjects achieved expert-level performance on the first attempt. All subjects achieved expert-level performance by the end of two additional attempts. While a significantly larger proportion of medical students (79.9%) successfully completed the helicopter test on the first attempt compared to corpsmen (54.3%), there were no statistically significant differences in mean SC completion times and checklist scores between both groups (P > 0.05). Medical students performed a SC only 1.3 s faster and scored only 0.16 points higher than corpsmen. The effect size for differences were small to negligible (Cohen's d range 0.18-0.33 for SC completion time; Cohen's d range 0.45-0.46 for checklist scores). CONCLUSION: This study successfully defined SC checklist scores and completion times based on the performance of experienced surgeons on a simulator. Using these criteria and the principles of mastery learning, novices with little knowledge and experience in SC were successfully trained to the level of experienced providers. All subjects met performance targets after training and overall performance plateaued after approximately seven iterations. Over two-thirds of subjects achieved the performance target on the first testing attempt in a simulated helicopter environment. Performance was comparable between medical student and corpsmen subgroups. Further research will assess the durability of maintaining SC skills and the timing for introducing refresher courses after initial skill acquisition.

Low-volume Hydrodissection for the Treatment of Chronic Achilles Tendinopathy.

Chronic Achilles tendinopathy (AT) is a common ailment for many active duty service members that adversely affects readiness. Patients present with pain, swelling, and limited functional ability. Kager's fat pad is a mass of adipose tissue that protects the blood vessels supplying the Achilles tendon and preserves its function. A popular hypothesis is that scarring, tethering, and neovascularization play a significant role in the pathogenesis of AT. Current literature supports the effectiveness of high-volume (40-50 mL) hydrodissection, a procedure in which fluid is injected under ultrasound guidance into the tissues surrounding the Achilles tendon to mechanically separate the paratenon from the underlying Kager's fat pad. There may also be a beneficial effect of scar tissue and neoneurovascular breakdown. However, high-volume injections result in short-term discomfort and decreased mobility. Lowering injection volume (2-10 mL) may reduce this morbidity and facilitate use in limited-resource environments. This case report presents a 29-year-old active duty male with recalcitrant post-traumatic AT who achieved significant pain reduction and faster return to full service using low-volume hydrodissection. The use of 10 mL volume has not been described previously and provides additional support for using lower volumes in chronic AT. This technique is a direct adjunctive treatment option with rehabilitation at a military treatment facility or in the operational environment.