Angled Ultrasonic Bone Curette-Assisted Circumferential Decompression for Thoracic Myelopathy Caused by Severely Anterior Ossification.

Objective: Thoracic myelopathy caused by severe anterior ossification is often progressive and fails to respond to conservative treatment. Removal of the compressing ossification is the most effective method but is hard to operate. In this study, we describe a novel one-stage posterior circumferential decompressive procedure assisted by an angled ultrasonic bone curette (UBC) for thoracic myelopathy caused by severe anterior ossification and evaluate its safety and efficacy.

Methods: The current study enrolled 15 consecutive patients (five men and 10 women) with thoracic myelopathy caused by severely anterior ossification between January 2017 and December 2019. All patients underwent posterior circumferential decompression assisted by angled UBC and segmental instrumentation with interbody fusion. At the time of surgery, the average age was 58.6 ± 6.3 years (47-70 years). Before and after surgery, the patient data, clinical manifestation, operative levels, blood loss, operative time, perioperative complications, Japanese Orthopaedic Association (JOA) score were recorded and analyzed retrospectively.

Results: All patients had successful one-stage posterior circumferential decompression to remove anterior ossifications directly. There were 12 cases of OPLL, two cases of a calcified giant herniated disc, and one case of osteophyte. The average operation time was 153.4 ± 53.4 min (77-242 min), with a mean blood loss of 463.5 ± 155.8 mL (240-780 mL). The average length of stay in the hospital was 14.3 ± 4.7 days (9-25 days) and the mean follow-up duration was 20.8 ± 8.8 months (12-39 months). Almost all patients had subjective improvement in motor power and gait. The average preoperative JOA score was 4.5 ± 1.6, which improved to 9.0 ± 1.8 at the final follow-up. Postoperative differences in the overall JOA scores showed significant improvement (F = 105.446, p < 0.01). The overall recovery rate at the final examination scored 70.9% ± 25.0%. According to Hirabayashi's classification, eight cases were rated as excellent, four as good, two as fair, and one as unchanged. No patient was graded as deteriorated. Two patients (13.3%) experienced intraoperative cerebrospinal fluid leakage, while two cases (13.3%) experienced unilateral intercostal neuralgia, and only one (6.7%) encountered acute neurological deterioration. All these patients were treated conservatively and their neurological function improved significantly. At the follow-up, there was no evidence of neurological deterioration.

Conclusion: Circumferential decompression assisted by angled UBC can preserve more posterior elements of the involved levels, maintaining an intact pleura and reducing the operation time and blood loss for thoracic myelopathy caused by severe anterior ossification. It is a safe, effective, and technically feasible method to provide surgeons with a new option for thoracic spinal circumferential decompression.