The Presence of Thyroid Cartilage at the Surgical Level Reduces Early Dysphagia after Single-Level Anterior Cervical Surgery: A Retrospective Study

Abstract

Background: Early dysphagia is a frequent complication of anterior cervical (AC) spine surgery. However, there are no reports that have discussed the correlation between early dysphagia and the positional relationship between thyroid cartilage and the surgical level.

Methods: We retrospectively enrolled 82 patients in our hospital who underwent single-level AC discectomy performed by the same surgeon using the same internal fixation apparatus from 2015 to 2017. Swallowing difficulty was rated during the first five postoperative days using a 10-point scoring system. The positional relationship between the thyroid cartilage and the surgical level was defined as discectomy within the thyroid cartilage (IN group) or outside the thyroid cartilage (OUT group) using preoperative computed tomography (CT) images. The confounding factors such as gender, age, body mass index (BMI), hypertension, diabetes mellitus, drinking, smoking, operative level, operative time, and blood loss were analyzed by a binomial logistic regression.

Results: The thyroid cartilage was most commonly located above the C5 level (65.1%). Early dysphagia developed in 47.6% of the patients during the first five postoperative days. The IN and OUT groups each contained 41 cases. The difference in the cumulative postoperative early dysphagia score between the IN and OUT groups was statistically significant (p < .05). The factors of gender, age, BMI, hypertension, diabetes mellitus, drinking, smoking, operative level, operative time, blood loss did not significantly influence the incidence of postoperative early dysphagia.

Conclusions: We found that early dysphagia, which is a self-limiting complication, was correlated with surgery performed at levels outside the thyroid cartilage region. Preoperative review of the positional relationship between the thyroid cartilage and the surgical level can predict the incidence of postoperative transient dysphagia.

Keywords:

• anterior cervical discectomy and fusion
• spine
• thyroid cartilage
• single-level
• early dysphagia
• cricoid cartilage

ETHICAL APPROVAL

Compliance with Ethical Standards. “All procedures performed in studies involving human participants were in accordance with the ethical standards of the Ethics Committee of The Second Affiliated Hospital of Wenzhou Medical University and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study formal consent is not required.”

ACKNOWLEDGEMENTS

We would like to thank Dao-liang Xu, MD, Jiao-xiang Chen, MD and Fang-min Mao, MD PhD, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, for their thoughtful discussions.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Funding

This work is supported by a major Science and Technology Program for Medical and Health of Zhejiang Province (Grant No. WKJ-ZJ-1527).