Surgical Strategy for Cervical OPLL with Kyphosis: Balancing Anterior, Posterior, and Combined Approaches – A Commentary on “Long-term Outcomes of Multilevel Anterior Cervical Osteotomy and Posterior Instrumentation for OPLL-Induced Myelopathy With Cervical Kyphosis”
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The surgical management of cervical ossification of the posterior longitudinal ligament (OPLL) remains a subject of considerable debate, particularly when severe kyphosis or large ossified masses are present. Posterior decompression procedures such as laminoplasty or laminectomy with fusion remain widely used for multilevel myelopathy, especially in elderly patients. However, their success depends on posterior cord drift, which is markedly limited in patients with fixed kyphosis or when the occupying ratio exceeds 50%–60%. In these situations, anterior decompression offers direct removal of the ossified mass and is generally considered superior.
However, anterior surgery presents formidable technical challenges. When the OPLL is firmly adherent to the dura, or when ossification extends cranially to C2 or caudally beyond the cervicothoracic junction, the risk of spinal cord injury and cerebrospinal fluid leakage increases substantially. These anatomical constraints explain why many surgeons hesitate to adopt an anterior-only strategy in complex cases.
Dynamic magnetic resonance imaging (MRI) has recently emerged as a valuable adjunct for surgical planning in degenerative cervical myelopathy, including OPLL. Static imaging may underestimate ventral cord compression in cases of kyphosis or segmental instability. By demonstrating changes in compression during flexion and extension, dynamic studies identify patients unlikely to benefit from posterior decompression alone. Persistent ventral compression despite extension favors an anterior or combined anterior-posterior approach, whereas adequate cord drift may still justify a posterior-only procedure [1,2]. Thus, incorporating dynamic MRI into preoperative evaluation helps refine indications, optimizes the surgical sequence, and potentially reduces operative risks.
The rationale for combining anterior and posterior approaches can be summarized in 3 principles. First, multilevel anterior decompression often requires augmented posterior fixation to maintain correction and prevent construct failure. Second, in cases of large OPLL or severe kyphosis, when the risk of cord injury during anterior removal is high, posterior decompression may be performed first, creating a safety margin before anterior manipulation (Fig. 1). Third, if decompression remains incomplete after anterior surgery, supplemental posterior surgery ensures adequate neural decompression and functional recovery [3].
Pre- and postoperative images of cervical ossification of the posterior longitudinal ligament (OPLL) with kyphosis. (A, B) Preoperative neutral lateral radiograph and sagittal reconstructed computed tomography (CT) demonstrate severe canal compromise caused by segmental OPLL. (C, D) Postoperative neutral lateral radiograph and sagittal reconstructed CT show correction of cervical alignment and sufficient decompression.
The study under discussion provides valuable long-term data [4]. Over more than 5 years of follow-up, multilevel anterior osteotomy with posterior fixation achieved durable neurological improvement, radiographic correction, and no implant-related complications. These findings underscore that combined strategies are not only safe but also practical for patients with OPLL and rigid kyphosis.
Nonetheless, several aspects merit further elaboration. The Ames osteotomy classification offers a valuable framework, but it does not fully capture OPLL-specific nuances such as en bloc versus floating resection. The authors’ choice of pedicle screws rather than lateral mass screws also warrants discussion, as the fixation strategy has direct implications for reproducibility and safety. Finally, although alignment correction was well maintained, gradual forward tilting of the cervical spine was observed, as reflected in increasing T1 slope and sagittal vertical axis. This pattern parallels findings in cervical deformity, where undercorrection and T1 slope-lordosis mismatch predispose patients to late imbalance and functional decline [5,6]. Future research should define optimal alignment goals-such as thresholds for C2-7 lordosis, T1 slope-lordosis mismatch, and chin-brow vertical angle-to further refine surgical targets.
In conclusion, anterior decompression is advantageous for patients with severe kyphosis or high canal-occupying ratios, but its risks escalate with dural ossification or cranial/caudal extension. Posterior decompression may be safer in these scenarios, though often inadequate. A combined anterior-posterior approach provides a pragmatic balance, ensuring decompression, deformity correction, and long-term stability. Continued refinement of indications, technical details, and alignment objectives will be essential to optimize outcomes for patients with this complex pathology.
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Conflict of Interest
The author has nothing to disclose.