Surgery for Thoracic Myelopathy due to Ossification of Ligaments with Intraoperative Ultrasonography and Ultrasonic Osteotome

Abstract

Posterior decompression using intraoperative ultrasonography and ！ he u 】 trasonic osteotome was investigated in 29 patients sufferlng 丘om thoracic myelopathy due to ossification of ljgaments． The lesions in 7 patients were OPLL ． 9 patients had OPLL accompanied with OYL The Iesions in the remaining 亅3were OYL ． The lesions of OPLL in sixteen patients involved 3． 4 vertebral bodies on average (2 to 8) ， and the lesions of OYL in 22 patients involved 3． 7 vertebral bodies on average (2 to l l) ． Twenty seven patients complained of gait dis田 rbance (Frankers C ； 17 patients ， D ； 10 patjenIs) ． The surgical pr edure was as fbllows；first ， ejther wide laminectomy was perf () rmed in the usua ］manner or OYL was resected using an u ］ trasonic osteotome ． After the dura was exposed ， the degree of decompression of the spinal cord from OPLL was evaluated using intraoperative ultrasonography ． In cases where there were insufficient decompression with severe palsy ， circum − spinal decompression was perf () rmed using the posterolateral approach through the lateral and the anterior wall of the spinal cana1 ． The OPLL was resected using the ultrasonic osteotome under intraoperative ultrasonographic observation ． In patients without severe palsy ， posterior stabilization without resection of OPLL was perforrned ， even if the degree of decompression was insufficient ． As a result of intraoperative ultrasonographic evaluation ， 6patients were shown to havc sufficient decompression and lO were shown to have insufficient decompression ． Of the latter 10 cases ， 7were treated with ¢ ircum − spinal decompression and 3 were treated by posterior stabilization． At the dme of the latter fbllow up observation ranging from l years to l L7 years (average 4 、 8 years) ， an the patients were able to walk although 150f them required support ． As regards to complic 飢 ions of surgery ， there was postoperative transient aggravation of palsy in 5 patients and cerebrospinal f］Uid leakage in 2 patients ・ Considerlng the preoperative severity of palsy and 山 e danger of spinal cord 面 uries due to surgery ， the surgical outcomes were satisfactory ． Therefbre ， intraoperative uhrasonography and the way of the ultrasonic osteotome were able to make such operations safer than the usual procedures in these cases ． Key word ： thoracic myelopathy ， ossification of thoracic ligament ， intraoperative ultrasonography ， ultrasonic osteotome Spinal Surgery l3 (3)：281-288 ， 1999

Effectiveness of Posterior Decompression for Patients With Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine

“…However, in patients with multiple lesions or with OLF, posterior decompression may still be the best available option because of the technical limitations of anterior decompression in thoracic lesions. [3][4][5]6,8 We therefore evaluated the effectiveness of posterior decompression from the findings of intraoperative ultrasonography.…”

“…MR-based ossification-kyphosis angles 3 and intraoperative ultrasonography 4 -6 were used to determine when posterior decompression succeeded or failed in providing adequate decompression of the thoracic cord where OPLL was present. Therefore, we reviewed the effectiveness of posterior decompression from the findings of intraoperative ultrasonography for patients with ossification of the posterior longitudinal ligament in the thoracic spine, 5,6 and evaluated various parameters from preoperative imagings.…”

“…[5][6][7]9,11 However, the treatment outcome of anterior decompression via the posterolateral approach is not necessarily favorable, and transient or permanent aggravation of paralysis has often been reported. 4,8,11 Therefore, Tsuzuki et al developed extensive cervicothoracic laminoplastic decompression, which aimed to increase the posterior decompression effect by extending the posterior decompression range.…”

“…In such conditions, other surgical options should be used. [1][2][3][4][5][6][7][8][9][10][11] Intraoperative ultrasonography is excellent diagnostic imaging that can evaluate the intradural state of spinal cord decompression, 5,6 and it should be used to judge the effectiveness of spinal decompression at more than a 20°ossifi-cation-kyphosis angle and in the final determination of the indication for additional surgical procedures. 5,6 Key Points • The effectiveness of posterior decompression surgery was reviewed in 22 patients with thoracic myelopathy resulting from the ossification of ligaments from the findings of intraoperative ultrasonography and various parameters on preoperative imaging.…”

Ossification of the Posterior Longitudinal Ligament: Etiology, Diagnosis, and Outcomes of Nonoperative and Operative Management

“…A positive echo-free space is a good indicator of adequate decompression. 51 An ossification kyphosis angle that is less than 23 degrees correlates with an echo-free space. 51 …”