Temporal progression and spatial distribution of "normal" prevertebral soft tissue swelling following central corpectomy for cervical spondylotic myelopathy

Objective: To document the temporal progression and spatial distribution of prevertebral soft tissue swelling (PSTS) after central corpectomy (CC) and to determine the variables affecting its severity. Background: The natural attributes of PSTS following CC for cervical spondylotic myelopathy (CSM) have not been characterized in literature. Materials and Methods: PSTS was measured at the C2 level and midpoint of the operated segment on lateral radiographs of the cervical spine taken pre-operatively and post-operatively (day 0, day 3/4, day 5 and day 6/7) in 93 patients with CSM undergoing one to three level uninstrumented CC. Patient's age, weight, Nurick's grade, number of corpectomy levels and intubation time were correlated with the PSTS. Results: Proportionately, the swelling was maximal at the C2 level rather than at the level of CC, on all days, irrespective of the level of surgery. At the C2 level, the increase in PSTS was maximum by day 3/4 ( P = 0.0001), whereas at the CC level, the PSTS continued to increase till day 5 ( P = 0.0001). PSTS was higher in patients undergoing a three-level CC and in those with inclusion of C4 in the CC ( P = 0.002). Conclusion: Patients undergoing CC are at risk for upper airway obstruction mainly at the C2 level in the first 3 days after surgery due to the PSTS. Those undergoing three-level CC, or having inclusion of C4 in the CC, have a greater degree of PSTS and have a higher risk of post-operative airway obstruction.