Preventing neurological deterioration after ambulation in posterior decompression and fusion for thoracic ossification of the posterior longitudinal ligament.

PurposeThe objective of this study was to clarify the characteristics of immediate neurological deterioration (ND) after ambulation and its potential preventative measures using multi-rod reinforcement during posterior decompression and fusion (PDF) with instrumentation for thoracic ossification of the posterior longitudinal ligament (T-OPLL).MethodsStudy 1: Fifteen patients with T-OPLL who underwent PDF before 2020 were included. Demographic, radiographic, intraoperative, and postoperative data were compared between the 6 patients with ND and 9 patients without ND after ambulation. Study 2: The primary (incidence of ND after ambulation) and the secondary (postoperative hospital stay) outcomes were compared between 15 patients with a multi-rod construct since 2020 (multi-rod group) and 15 patients with a dual-rod construct before 2020 (dual-rod group; patients who were indicated in study 1).ResultsStudy 1: ND after ambulation tends to occur only in the upper or middle thoracic spine. The mean maximum OPLL occupation ratio was significantly different between the groups (ND vs non-ND, 67.7% vs 53.4%; p = .021). Study 2: The incidence of ND after ambulation (dual-rod vs multi-rod, 40% vs 6.7%; p = .040) and the mean duration of the postoperative hospital stay (dual-rod vs multi-rod, 51.2 days vs 25.6 days; p = .007) were significantly different between the groups.ConclusionsImmediate ND after ambulation occurs in the upper or middle thoracic spine, and a higher maximum OPLL occupation ratio is a significant risk factor. Multi-rod reinforcement can reduce its incidence, regardless of maximum OPLL occupation ratio, and duration of postoperative hospital stay, which could be a potential preventative measure.