Cervical Laminoplasty

Cervical Laminoplasty

Nikhil A. Thakur, MD

Brett A. Freedman, MD

John G. Heller, MD

Dr. Freedman or an immediate family member has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Medtronic. Dr. Heller or an immediate family member has received royalties from Medtronic; is a member of a speakers’ bureau or has made paid presentations on behalf of Medtronic; serves as a paid consultant to or is an employee of Medtronic; has stock or stock options held in Medtronic; and serves as a board member, owner, officer, or committee member of the Cervical Spine Research Society. Neither Dr. Thakur nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.



The two major schools of laminoplasty derive from the Hirabayashi “open-door” procedure and Kurokawa’s “French-door” technique. Other subsequently described techniques are variations on these themes. These techniques are illustrated in Figure 2. Most differ in how the surgeon secures the laminae in their new position or in how the exposure is made. Initially, hinges were either tethered open with suture or wire or propped open with bone grafts or other spacers, such as ceramic or polyethylene blocks. Recent innovations have adapted plates and screws to securely fix the laminae in place.

FIGURE 2 Illustrations depict common techniques used for cervical laminoplasty. A, Single-door laminoplasty. Sutures are placed through the spinous process to the articular capsule on the hinge side to hold the lamina elevated. B, Double-door laminoplasty. The spinous process is osteotomized in the midline, and the two halves are pried open on laterally based hinges. Structural bone graft or a spacer fills the defect between the split spinous processes and prevents closure of the laminoplasty doors. C, Single-door laminoplasty with use of bone graft or a spacer to prop the door open. D, Single-door laminoplasty with use of a laminoplasty plate. E, Unilateral muscle-stripping approach; this approach is used to maintain the integrity of soft tissues on the contralateral side. The laminae on one side are exposed, with preservation of the nuchal, supraspinous, and interspinous ligaments. The spinous processes are osteotomized at their bases and are reflected to the intact side, allowing exposure of the posterior laminar bone. The arrows indicate the plane of the osteotomy and exposure.


The preoperative diagnostic imaging workup should consist of plain radiographs of the cervical spine, including AP and neutral lateral radiographs (Figure 3). Flexion-extension views have been shown in some studies to be useful in determining the presence of instability, such as spondylolisthesis. Sakai et al3 showed that the presence of a posterior spondylolisthesis resulted in significantly lower Japanese Orthopaedic Association recovery rates compared with anterior spondylolisthesis or no spondylolisthesis (which had equivalent outcomes).

The K-line (kyphosis line) concept was introduced by Fujiyoshi et al4 as a tool to determine if laminoplasty could be used successfully in patients with OPLL. This tool can also be extended to address large ventral lesions or fixed kyphoses, which are often contraindications to laminoplasty. The K-line was defined as the line connecting the
midpoints of the spinal canal at C2 and C7 on a lateral cervical radiograph.4 A positive (+) K-line did not have an OPLL lesion crossing it, whereas a negative (−) K-line was present when the pathology extended dorsally beyond the line (Figure 4). In the (+) K-line group, the average neurologic recovery rate following laminoplasty was 66%, compared with 19% in the (−) K-line group. An MRI study is useful in preoperative planning to determine which levels need to be included in the laminoplasty. Moreover, MRI allows the surgeon to determine if a C2 dome laminectomy should be included with the laminoplasty technique. Factors such as hypertrophied flavum, congenital stenosis, and cervical spine lateral architecture can result in impingement of the cord at the C2 level after laminoplasty due to cord drift-back and cause postoperative myelopathy.

FIGURE 3 Neutral lateral radiograph of the cervical spine demonstrates multilevel cervical spondylosis/spondylolisthesis.

FIGURE 4 Illustration of the K-line (kyphosis line) concept. A positive (+) K-line (A) occurs when the compressive pathology ossification of the posterior longitudinal ligament remains ventral to the line. A negative (−) K-line (B) is defined by the pathology extending dorsally to or across the line.

The use of a CT study or a CT myelogram study is surgeon and patient specific. A CT scan gives the surgeon a more precise appreciation of the bone anatomy, including the presence of OPLL (Figure 5), ossified ligamentum flavum, or foraminal stenosis with osteophyte formation. Foraminal stenosis detected on CT and correlated with physical examination can be addressed during the surgical procedure, with a foraminotomy on the affected side. Myelography enhances structural detail, including details of patterns of compression and thickness and shape of lamina. At times, it is indicated when the MRI leaves some doubt as to the nature and extent of the pathology. A CT scan also helps determine the “occupation ratio” for a large ventral lesion (AP diameter of the lesion/AP diameter of the canal × 100). An occupation ratio of more than 50% to 60% is often considered a relative contraindication to laminoplasty. These additional anatomic details can provide important tactical information to be used intraoperatively.

Feb 2, 2020 | Posted by in ORTHOPEDIC | Comments Off on Cervical Laminoplasty

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