Anterior Decompression via a Single Posterior Approach Using the Ultrasonic Bone Scalpel for the Treatment of the Thoracic Segmental Ossification of Posterior Longitudinal Ligament: A Report of Three Cases

INTRODUCTION: Thoracic myelopathy due to ossification of the posterior longitudinal ligament (T-OPLL) is an indication for surgical treatment because the symptom is usually progressive. The surgery for T-OPLL is technically challenging for several reasons. Various operational procedures were developed for dealing with T-OPLL. The anterior decompression through a single posterior approach is a procedure to achieve the complete decompression via the direct resection of the ossified lesion, especially for the beak-type OPLL. Previous reports showed better postoperative outcomes using this method than using other procedures. However, the difficulty and risk of complications are also reported because of the blinded resection of the lesion positioning ventrally to the dura mater. TECHNICAL NOTE: We describe a novel method using an anterior decompression through a single posterior approach using an ultrasonic bone scalpel. The following procedure is for a case of beak-type OPLL at the T5-6 level. The posterior elements at T2-9 were exposed after a median skin incision was created above a spinous process. First, pedicle screws were inserted bilaterally at T3-5 and T7-9. After the laminectomies and dekyphosis maneuver at T3-9, the spinal cord compression by OPLL was evaluated using intraoperative ultrasonography. After the slight medial facetectomy and pediclotomy at T5-6, the ultrasonic bone scalpel was inserted through the bilateral side of the spinal cord. The tip of the handpiece was angled to reach OPLL. The resection of OPLL was performed under intraoperative spinal cord monitoring. The intraoperative ultrasonography revealed the normal pulsation of the spinal cord and the space between the vertebral body and dura mater after completing the resection of OPLL. Posterolateral fusion was completed with local bone and harvested iliac crest. CONCLUSIONS: The anterior decompression through a single posterior approach using an ultrasonic bone scalpel is a safe and effective treatment of thoracic OPLL.