Prevertebral Soft-Tissue Swelling Following One-Level Anterior Cervical Diskectomy and Fusion: An Analysis Based on Surgical Level.

The purposes of this study were to identify the primary level at which prevertebral tissue swelling (PSTS) occurs following one-level anterior cervical diskectomy and fusion (ACDF) based on surgical level, and to quantify the degree to which it occurs. Although PSTS peaks at day 2 or 3 after ACDF, with swelling noted to be prominent at the C2-C4 levels, the way in which the features of PSTS vary according to surgical level has not been examined.Thirty-seven patients who underwent one-level ACDF were reviewed and classified into retropharyngeal and retrotracheal groups based on surgical level. PSTS occurring at C2-C6 and the width of the airway (WA) at C2-C4 were assessed using plain radiographs before surgery and at 1, 3, 5, and 7 days postoperatively.The retropharyngeal group comprised 10 patients, while the retrotracheal group comprised 27 patients. The retropharyngeal group had the most severe PSTS on day 3 after surgery. C4 showed PSTS peaked on day 3, with a value of 3.26 times the preoperative prevertebral tissue thickness. The WA at C4 was narrowest on day 1, with a value of 0.74 times and remained narrow until day 3. The retrotracheal group showed the most severe PSTS on day 1 at the C3 level: 2.81 times. The WA at C4 was narrowest on day 1 with a value of 0.78 times and increased thereafter.PSTS following one-level ACDF for both retropharyngeal and retrotracheal lesions was greatest at the C3 and C4 levels, with peaks on the third day after operation for the former and the first day for the latter. The WA at C4 was narrowest from day 1 in both groups. In the retropharyngeal group, narrowing remained until day 3.