Posterior Surgery for Cervical Myelopathy: Laminectomy, Laminectomy with Fusion, and Laminoplasty

Cervical myelopathy describes a constellation of symptoms and signs arising from compression of the cervical spinal cord (Table 1). Because the presentation of the myelopathic patient can be quite subtle in its early manifestations, the diagnosis may easily be missed or wrongly attributed as a "normal" epiphenomenon of aging. However, because the natural history is typically one of stepwise progression, early recognition and treatment is essential for optimal outcomes before the onset of irreversible spinal cord damage. Table 1 Potential clinical findings in cervical myelopathy* Considerable debate exists regarding the optimal surgical approach for treating multilevel cervical myelopathy1,2. Proponents of anterior surgery cite as advantages the ability to directly remove the majority of compressive pathologies encountered in the cervical spine (e.g., disc herniations, ventral osteophytes, osteophytes or ossification of the posterior longitudinal ligament [OPLL]), the muscle sparing dissection which results in minimal postoperative pain, and the ability to correct and decompress the cord over kyphotic lesions. Indeed, if myelopathy arises from one or two segments, the supremacy of an anterior approach is difficult to argue. However, when three or more segments are involved, accelerated complication rates associated with anterior surgery, particularly fusion related problems seen with long strut grafts used to reconstruct multilevel corpectomies, make posterior options more attractive. Posterior based operations -- such as laminectomy, laminectomy and fusion, and laminoplasty -- possess their own distinct set of advantages. First, because an indirect decompression is performed, posterior surgeries are generally technically easier operations to perform than anterior corpectomies, particularly in multilevel patients with severe stenosis or OPLL that requires resection. Accordingly, all challenges associated with graft carpentry to reconstruct the anterior column are avoided. Second, posterior decompression allows the surgeon to rapidly decompress multilple segments more quickly than is possible with a multilevel anterior decompression. This may be critical in treating debilitated patients who need a quick decompressive procedure. Third, motion-preserving posterior operations like laminoplasty allow cord decompression without necessitating fusion and its attendant complications. Fourth, because fusion is not routinely necessary with some posterior approaches like laminoplasty, laminoplasty allows decompression of segments at future risk in one operation without substantially increasing patient morbidity. With a laminoplasty, a C3 to C7 decompression can be routinely performed with one operation, even if the majority of the stenosis is at, for example, C4-7, with a mild or moderate amount of stenosis at C3-4. In contrast, if an anterior approach were used in the same patient, one might hesitate to include a mildly/moderately stenotic level at C3-4 for fear of increasing complications and morbidity, but then leave the patient vulnerable to subsequent disease at that adjacent level over time. Posterior surgery is not appropriate in all myelopathic patients, however, and it clearly has its own set of drawbacks as well. It is associated with extensive posterior muscle denervation and a less cosmetically appealing scar. Additionally, as most of the compressive structures that lead to cervical myelopathy arise anteriorly, posterior-based procedures for spinal cord decompression rely on the ability of the cord to drift away from the anterior lesions as a result of releasing the posterior tethers (laminae, ligamentum flavum). Although such drift back reliably occurs in a lordotic or neutral cervical spine, it may not occur in the setting of significant kyphosis. Thus, the indications for performing posterior decompression are limited to those in whom the overall sagittal alignment is conducive to cord drift-back. In certain situations, posterior based operations for cervical myelopathy may not be sufficient, requiring anterior or combined anterior and posterior approaches (Fig. 1). Fig. 1 General guidelines for surgical management of cervical myelopathy In this paper, we examine the roles of posterior decompression procedures-laminectomy, laminectomy and fusion, and laminoplasty-in the treatment of multilevel cervical myelopathy.