The role of prevertebral soft tissue swelling in dysphagia after anterior cervical corpectomy fusion: change trends and risk factors

OBJECTIVES: This study aimed to analyze the change trends of prevertebral soft tissue swelling (PSTS) for anterior cervical corpectomy fusion(ACCF) and to evaluate the risk factors of PSTS for postoperative dysphagia. METHODS: There were 309 patients with degenerative cervical diseases who were treated with ACCF from November 2015 and September 2019 in our hospital. According to the symptom of swallowing function after ACCF, those were divided into the dysphagia group and the normal-swallowing function group. Cervical computed tomography(CT) was analyzed, and radiological evaluation of the prevertebral soft tissue was measured between the antero-inferior corner of each vertebral body and the air shadow of the airway through CT mid-sagittal slice images before operation and after operation(one week, one month, eight months and twelve months). RESULTS: The incidence of dysphagia after ACCF was 41.1%. 120 of 127(94.5%) patients had dysphagia disappeared at the 8 months after ACCF, and all disappeared at the 12 months. In both groups, PSTS would be biggest at 1 week postoperatively comparing to the preoperative, and then get smaller from 1 week to 12 months postoperatively (p < 0.05). After 12 months of operation, the PSTS of all cervical spinal levels would get equal to the preoperative size in the normal-swallowing function group, while the PSTS in dysphagia group would get equal only in C5-7 levels. The PSTS of preoperative C6 level and postoperative C2 level were more closely related to the present of postoperative dysphagia (OR: 9.403, 95%CI: 2.344–37.719, OR: 3.187, 95%CI: 1.78-5.705). It was more important to predict postoperative dysphagia using the value of PSTS at preoperative C6 level and postoperative C2 level, with the cutoff threshold for the PSTS of preoperative C6 level ≦1.51 cm and postoperative C2 level ≦1.3915 cm, which could get sensitivity & specificity 66.929% and 61.54%, 77.17% and 64.29%, respectively. CONCLUSION: Our study showed that the increasing of the PSTS after ACCF should be considered as a risk factor of dysphagia after surgery. With the recovery of PSTS over time, the incidence of postoperative dysphagia decreases. The PSTS of preoperative C6 level and and postoperative C2 level should play an important part in predicting the risk of postoperative dysphagia.