"Floating Island" Technique: Case Series of a Novel Technique for Surgical Management of Interdigitating Calcified Thoracic Disc Herniations

Objective: The objective of this study was to describe the use of a novel approach, the "floating island" technique to surgically address calcified thoracic disc herniation (cTDH) that interdigitates with adjacent dura and to report clinical and radiographic outcomes of patients.

Methods: A retrospective case series was conducted by examining the electronic medical records of consecutive patients who underwent thoracic discectomy from August 2017 to December 2022. Of 65 patients treated for thoracic disc herniation, 37 had cTDHs. Five of these 37 patients underwent treatment with the floating island technique, which involves osseous separation, debulking, and ligamentous separation.

Results: The floating island technique was applied using the posterolateral approach in 3 patients and the anterolateral approach in 2 patients. One patient experienced a cerebrospinal fluid leak, which was managed without a lumbar drain. All patients showed radiographic improvement of spinal cord compression postoperatively and were admitted to an intensive care unit for one night. Hospital stays ranged from 2 to 6 nights, with 4 patients discharged home and 1 to a rehabilitation facility. Neurological improvement or baseline status was observed in all patients at discharge, with follow-up ranging from 9 to 24 months. Nurick grade improved in all patients by at least 1 point, with no progression of symptoms.

Conclusion: The floating island technique offers a promising option for the surgical management of interdigitating cTDH, demonstrating excellent immediate radiographic and long-term clinical outcomes. Further studies are needed to validate these findings and determine the technique's generalizability.