Clinical characteristics and surgical strategies of tandem ossification of the intraspinal ligaments / 中华骨科杂志

ABSTRACT

Ossification of posterior longitudinal ligament (OPLL) and ossification of ligamentum flavum (OLF) are clinically common heterotopic ossification diseases, which are the main causes of cervical and thoracic spinal stenosis and spinal cord injury. In some cases, OPLL and OLF may involve multiple spinal sites, individually or concurrently, increasing the difficulty of clinical diagnosis and treatment. This review initially attempts to define this specific ossification phenomenon as Tandem ossification of intraspinal ligaments (TOIL). It refers to a kind of severe spinal ligament ossification diseases caused by multiple factors, that OPLL and OLF occur alone or in combination at two or more sites of the cervical, thoracic, or lumbar spine with five or more ossified segments, progressively compressing the spinal cord or nerves, thereby resulting in a series of complex clinical symptoms. The prevalence of TOIL remains unknown, but its clinical detection rate is relatively high, and the most common TOIL is cervical OPLL combined with thoracic OPLL or/and OLF. Moreover, occurrence and development of TOIL involve many factors and its definitepathogenesis is not clear. Damage of upper and lower motor neurons can occur simultaneously in TOIL patients so that their clinical symptoms and signs often interfere with each other. TOIL has various forms, complex imaging features, and no uniform diagnostic and localization diagnostic criteria, which may easily lead to missed diagnosis and misdiagnosis. It is recommended that TOIL is identified by the typical symptoms and signs as the basis, CT three-dimensional reconstruction and MRI signs as the reference, and combination of the possible risk factors and clinical experience. Currently, surgical decompression for responsible lesions is the only effective treatment for symptomatic TOIL. However, domestic and foreign scholars still have great arguments on the optimal surgical strategy of TOIL. No consensus has been reached on how to determine the operating segment and the extent of decompression, which surgical approach and technique to be adopted, and when to select staged or one-stage combined surgery. Therefore, this review summarizes and discusses the current status and progress of the clinical characteristics and surgical strategies of TOIL through searching the relevant literature, to provide a reference for clinicians to diagnose and treat TOIL.