The role of C2-C7 angle in the development of dysphagia after anterior and posterior cervical spine surgery

Abstract

Objective To analyze the relationship between cervical alignment and the development of dysphagia after anterior and posterior cervical spine surgery (AC and PC). Methods A total of 354 patients were reviewed in the present study, including 172 patients who underwent the AC procedure and 182 patients who had the PC procedure between June 2007 and May 2010. The presence and duration of postoperative dysphagia were recorded via face-to-face questioning or telephone interview performed at least 1 year after the procedure. The preoperative and postoperative neutral lateral cervical spine radiographs were evaluated. The C2-C7 angles were measured twice by the same researcher, independently, using the same methods. The change in C2-C7 angle (dC2-C7 angle) was equal to the difference between postoperative and preoperative. Results There were 12.8% AC (22/172) and 9.3% PC (17/182) patients reported dysphagia after cervical surgery. Of them, 12 patients could be graded as "mild", 8 patients as "moderate", and 2 patients as "severe" dysphagia in AC group, following the dysphagia grading system defined by Bazaz. There were 11 patients graded as "mild", 5 patients as "moderate", and 1 patient as "severe" dysphagia in PC group. No statistical significance was found between AC and PC group (χ2=0.513, P=0.545). Logistic regression analysis revealed that the dC2-C7 angle had considerable impact on postoperative dysphagia (OR=1.141, P=0.001). The chance of developing postoperative dysphagia in patients with dC2-C7 angle larger than 5 degree (64.1%) was significantly greater than that with lower than 5 degree (34.9%, χ2=10.831, P=0.001). Age, gender, BMI, operative time, blood loss, procedure type, revision surgery, most cephalic operative level and number of operative levels did not significantly influence the incidence of postoperative dysphagia (P>0.05). No relationship was found between the dC2-C7 angle and the degree of dysphagia (RR=-0.012, P=0.516). Conclusion Postoperative dysphagia is a common complication after cervical surgery. The dC2-C7 angle may play an important role in development of dysphagia in both AC and PC surgery. Over-enlargement of cervical lordosis should be avoided in order to reduce the rate of development of postoperative dysphagia. Key words: Deglutition disorders; Cervical vertebrae; Diskectomy; Spinal fusion; Postoperative complications