Objective To explore short-term effectiveness of floating island laminectomy surgery in treating thoracic spinal stenosis and myelopathy caused by ossification of the ligamentum flavum. Methods A total of 31 patients with thoracic spinal stenosis and myelopathy caused by thoracic ossification of the ligamentum flavum between January 2019 and April 2022 were managed with floating island laminectomy surgery. The patients comprised 17 males and 14 females, aged between 36 and 78 years, with an average of 55.9 years. The duration of symptoms of spinal cord compression ranged from 3 to 62 months (mean, 27.2 months). The lesions affected T1-6 in 4 cases and T7-12 in 27 cases. The preoperative neurological function score from the modified Japanese Orthopaedic Association (mJOA) was 4.7±0.6. Surgical duration, intraoperative blood loss, and complications were recorded. The thoracic MRI was conducted to reassess the degree of spinal cord compression and decompression after operation. The mJOA scoring system was employed to evaluate the neurological function and calculate the recovery rate at 12 months after operation. Results The surgical duration ranged from 122 to 325 minutes, with an average of 204.5 minutes. The intraoperative blood loss ranged from 150 to 800 mL, averaging 404.84 mL. All incisions healed by first intention after operation. All patients were followed up 12-14 months, with an average of 12.5 months. The patients' symptoms, including lower limb weakness, gait disorders, and pain, significantly improved. The mJOA scores after operation significantly increased when compared with preoperative levels (P<0.05), gradually improving with time, with significant differences observed among 1, 3, and 6 months (P<0.05). The recovery rate at 12 months was 69.76%±11.38%, with 10 cases exhibiting excellent neurological function and 21 cases showing good. During the procedure, there were 3 cases of dural tear and 1 case of dural defect. Postoperatively, there were 2 cases of cerebrospinal fluid leakage. No aggravated nerve damage, recurrence of ligamentum flavum ossification, or postoperative thoracic deformity occurred. ConclusionThe floating island laminectomy surgery is safe for treating thoracic spinal stenosis and myelopathy caused by ossification of the ligamentum flavum, effectively preventing the exacerbation of neurological symptoms. Early improvement and recovery of neurological function are achieved.