Midline delta double-door decompression (MDDD), a novel strategy for thoracic ossification of the ligamentum flavum via uni-portal noncoaxial spinal endoscopic surgery (UNSES): a case series.

objectiveThoracic ossification of the ligamentum flavum (TOLF) is the primary cause of thoracic spinal stenosis (TSS). Conventional decompression surgeries require surgical instruments to be inserted into the spinal canal, which is associated with risks such as dural tears, cerebrospinal fluid (CSF) leakage and even spinal cord injury, potentially resulting in devastating neurological deficits. This study introduces a novel surgical technique named midline delta double-door decompression (MDDD), assesses its feasibility and safety and elaborates on its potential advantages.

methodsA retrospective analysis was performed on the clinical data of 13 patients with TOLF who underwent MDDD from 2024 to January 2025. All the enrolled patients presented with symptoms of upper motor neuron injury, and some patients experienced complications of intermittent claudication. Centring on the core concept of the midline delta safe zone, a gradient progressive surgical strategy from the safe zone to the lesion boundary was adopted to standardize the surgical procedure. The double-door decompression mode was applied to achieve complete spinal cord decompression without any contact with the spinal cord. All patients received postoperative follow-up for more than 9 months. The modified JOA score for thoracic myelopathy (mJOA) was used to evaluate the improvement in clinical symptoms. Postoperative thoracic CT and MRI were performed to assess lesion resection efficacy and spinal stability.

resultsAll surgeries were successfully completed without conversion to open surgery. No cases of intraoperative spinal cord injury, CSF leakage or severe postoperative neurological deterioration occurred. The mean operative time was 106.15 ± 8.58 min, with an average intraoperative blood loss of 143.08 ± 24.96 mL. The spinal canal anteroposterior diameter (SCAD) and cross-sectional area significantly increased postoperatively. At the mean 12.8-month follow-up, the mean mJOA score increased from 5.46 ± 0.78 preoperatively to 9.46 ± 0.78, with a mean neurological recovery rate (RR) of 57.72%. Eight patients achieved excellent outcomes, and five achieved good outcomes.

conclusionGuided by the midline delta safe zone, MDDD via UNSES achieves spinal cord decompression without intraspinal instrument invasion. All enrolled patients experienced effective spinal canal expansion and favourable neurological recovery at the midterm follow-up. The data support the short-term effectiveness of this procedure.