Surgical management of giant calcified thoracic disc herniation and the role of neuromonitoring. The outcome of large mono centric series

Abstract

Purpose: Giant thoracic disc herniations (GTDH) are considered a subgroup of TDHs with worse functional outcomes, a high calcification rate, and a considerable risk of complications. We aimed to determine whether there is a relationship between the extent of calcification of GTDH and outcomes concerning the risk of complications, the surgical technique, and changes in neuromonitoring signals.

Methods: We present a retrospective analysis of 76 patients undergoing surgery for calcific GTDH. We introduced and defined a radiological definition of the calcified disc into"fully calcified" and "partially calcified." We performed a statistical analysis between clinical and radiological variables, type of surgical procedure, the extent of excision, neuro-monitoring signals, and outcome, comparing a group of 58 "fully-calcified TDH" patients and 18 "partially-calcified TDH" patients.

Results: Fully calcified TDHs, compared with partially calcified TDHs, do not have significant differences in outcome (worse outcome 4/58-6.9% versus 0/18, p = 0.25) and complications (10/58-17.24% versus 4/18-22.2%, p = 0.63); Fully calcified TDH is associated with a higher risk of alterations in neurophysiological potentials (14/58-24.1% versus 0/18, p = 0.02) and subtotal excision (18/58-31% versus 2/18-11%, p = 0.15), without significant differences between the approaches used.

Conclusion: Fully calcified TDH group has a similar outcome and complication rate as the partially calcified TDH group, but they are associated with higher intraoperative neuromonitoring signal changes. We introduced a new classificationsystem that guides the approach and helps tocounsel the patients.

Keywords: Neurophysiology; Neurosurgery; Spine; Thoracic disc herniation.