Turkish Neurosurgery 2021 , Vol 31 , Num 6
A New Indicator Predicting the Degree of Cord Shift After Posterior Decompression of Cervical Ossification of the Posterior Longitudinal Ligament Extended to the C2 Level and Its Clinical Usefulness
Byung-Jou LEE1,Subum LEE2,Sang-Ryong JEON3,Sung Woo ROH3,Jin Hoon PARK3,
1Inje University Ilsan Paik Hospital, Neuroscience & Radiosurgery Hybrid Research Center, College of Medicine, Department of Neurosurgery, 170, Juwharo, Ilsan Seogu, Goyang, Gyeonggi 10380, Republic of Korea
2Kyungpook National University Hospital, Kyungpook National University School of Medicine, Department of Neurosurgery, Daegu, Korea
3Asan Medical Center, University of Ulsan College of Medicine, Department of Neurosurgery, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, South Korea
DOI : 10.5137/1019-5149.JTN.31668-20.1 AIM: To evaluate the usefulness of the rostral line (R-line) as a new index for determining the degree of C2 lamina decompression in the context of ossification of the posterior longitudinal ligament (OPLL) extending to the C2 level.

MATERIAL and METHODS: The R-line was devised based on the mechanism by which the cord is shifted backward following cervical posterior decompression. According to their R-line status, 36 patients with cervical OPLL extending to the C2 level were divided into two groups of R-line (+) and R-line (?) cases, where the R-line touched the upper half of the posterior C2 lamina in the R-line (+) group and the inferior half of the posterior C2 lamina in the R-line (?) group, respectively.

RESULTS: Eighteen patients were classified as R-line (+) and 18 patients were classified as R-line (?). Total laminectomy of the C2 lamina was more common in the R-line (+) group, while dome-shape C2 laminectomy was more common in the R-line (?) group. All patients requiring reoperation were included in the R-line (+) group. Only the operation type showed a statistically significant difference according to the need for reoperation in the R-line (+) group; specifically, all patients who underwent reoperation in the R-line (+) group had dome-shape C2 laminectomy. It was determined that the risk factor for reoperation in the R-line (+) group was a history of dome-shape C2 laminectomy.

CONCLUSION: If the R-line touches the upper half of the posterior C2 lamina, total decompression of the C2 lamina should be performed. Keywords : Axis, Cervical vertebra, Laminectomy, Ossification of the posterior longitudinal ligament, Posterior decompression, R-line

Corresponding author : Jin Hoon PARK, jhpark@amc.seoul.kr