Background context: Prevertebral soft tissue swelling (PSTS) after anterior cervical spine surgery (ACSS) has been regarded as one of the critical complications that cause airway obstruction. Still, however, no research has dealt with how PSTS returns to presurgery status after ACSS; most recommendations are being performed without information about its natural course, focusing on acute-phase swelling after surgery.
Purpose: The study aimed to examine how long postsurgery PSTS lasts and when it returns to its presurgery state, and to analyze the actual influence of a number of factors to observe the natural progress of postsurgery PSTS.
Study design/setting: This is a prospective observational study.
Patient sample: The sample included a total of 160 patients who underwent ACSS, including anterior cervical discectomy and fusion (ACDF) and cervical total disc replacement (TDR).
Outcome measures: The diameter of PSTS measured at each set time point after surgeries was compared with PSTS measurements before surgery, and analyzed with factors influencing PSTS.
Methods: Anterior and posterior diameters of the anterior soft tissue of C3 (pharyngeal airway) and C6 (laryngeal airway) were measured using simple lateral radiography before surgery, immediately after surgery, at 2 weeks, 1, 3, 6, and 12 months after surgery. The progress of postsurgery PSTS was analyzed according to patients' individual characteristics, such as age, gender, weight, body mass index (BMI), smoking status, use of antiplatelet therapy, hypertension and diabetes mellitus, complaints of dysphagia, along with surgical factors such as anesthesia time, operation time, numbers of involved operation segments, transfusion, estimated blood loss , and operation method. Multivariable analysis by generalized linear mixed model was used to perform additional univariable analysis on variables found to be related to PSTS. In addition, to find the postsurgery interval at which PSTS naturally stabilizes, repeated measures analysis of variance and Bonferroni method were used to perform post-hoc tests. There were no sources of funding and no conflicts of interest associated with this study.
Results: For ACDF, the mean values (95% confidence interval [CI]) of PSTS in C3 were 4.38 (4.04~4.71), 10.40 (9.64~11.17), 7.72 (7.10~8.35), 6.24 (5.74~6.69), 5.43 (5.03~5.82), 5.14 (4.77~5.50), and 4.96 (4.59~5.33) mm at each follow-up time, respectively. In C6, the average values (95% CI) of PSTS were 14.43 (13.96~14.91), 19.18 (18.59~19.77), 17.92 (17.37~18.47), 16.98 (16.45~17.51), 16.18 (15.67~16.69), 15.95 (15.50~16.40), and 15.49 (15.50~16.40) mm. For cervical TDR, the mean values (95% CI) of PSTS in C3 were 3.67 (3.45~3.89), 8.05 (7.17~8.93), 5.42 (4.92~5.91), 4.57 (4.21~4.92), 4.12 (3.99~4.36), 4.10 (3.87~4.34), and 3.90 (3.66~4.14) mm at each follow-up time, respectively. In C6, the average values (95% CI) of PSTS were 13.61 (12.96~14.25), 16.51 (15.80~17.21), 15.77 (15.13~16.42), 15.24 (14.61~15.87), 14.62 (14.01~15.22), 14.52 (13.88~15.17), and 13.94 (13.20~14.68) mm. It is discovered that PSTS after surgery returned to presurgery status within 1 to 3 months in the pharyngeal airway (C3) and within 3 to 6 months in the laryngeal airway (C6), and gender, BMI, and surgery method (ACDF) were determined to be the factors having influence on PSTS after surgery.
Conclusions: It is necessary to pay attention to PSTS and patient conditions after ACSS for at least 1 to 6 months postsurgery, depending on surgical method and operation levels.
Keywords: ACDF; Anterior cervical spine surgery; Factors; Natural course; Prevertebral soft tissue swelling; TDR.
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