1.Biomechanical Study of Cervical Endplate Removal on Subsidence and Migration in Multilevel Anterior Cervical Discectomy and Fusion
Maohua LIN ; Rudy PAUL ; Stephen Z. SHAPIRO ; James DOULGERIS ; Timothy E. O’CONNOR ; Chi-Tay TSAI ; Frank D. VRIONIS
Asian Spine Journal 2022;16(5):615-624
Methods:
Model 1 (M1) was an intact C2C6 model with a 0.5 mm endplate. In model 2 (M2), a cage was implanted after removal of the C4–C5 and C5–C6 discs with preservation of the osseous endplate. In model 3 (M3), 1 mm of the osseous endplate was removed at the upper endplate. Model 4 (M4) resembles M3, except that 3 mm of the osseous endplate was removed.
Results:
The range of motion (ROM) at C2C6 in the M2–M4 models was reduced by at least 9º compared to the M1 model. The von Mises stress results in the C2C3 and C3C4 interbody discs were significantly smaller in the M1 model and slightly increased in the M2–M3 and M3–M4 models. Migration and subsidence decreased from the M2–M3 model, whereas further endplate removal increased the migration and subsidence as shown in the transition from M3 to M4.
Conclusions
The M3 model had the least subsidence and migration. The ROM was higher in the M3 model than the M2 and M4 models. Endplate preparation created small stress differences in the healthy intervertebral discs above the ACDF site. A 1 mm embedding depth created the best balance of mechanical strength and contact area, resulting in the most favorable stability of the construct.
2.The laryngopharyngeal nerve: a comprehensive review
Stephen SHAPIRO ; Andrew L. PARKER ; Juan J. CARDONA ; Arada CHAIYAMOON ; Francisco REINA ; Ana CARRERA ; Joe IWANAGA ; Aaron S. DUMONT ; R. Shane TUBBS
Anatomy & Cell Biology 2023;56(3):299-303
The laryngopharyngeal nerve has received much less attention that the other contributions to the pharyngeal plexus i.e., glossopharyngeal and vagus nerves. Often, in descriptions and depictions, the nerve is simply labeled as the sympathetic contribution to the pharyngeal plexus. As there is such scant information available regarding this nerve, the present review was performed. Very little is found in the extant medical literature regarding the laryngopharyngeal nerve. However, based on available data, the nerve is a consistent contributory to the pharyngeal plexus and serves other adjacent areas e.g., carotid body. Therefore, a better understanding of this structure’s anatomy is important for those who operate in this area. Further studies are necessary to better elucidate the true function of the laryngopharyngeal nerve.