Biomechanics of open-door laminoplasty with and without preservation of posterior structures

Abstract

laboratory iNveStigatioNC erviCal open-door laminoplasty (ODL) decompresses the spinal canal while maintaining nearphysiological cervical range of motion (ROM). In contrast to a standard laminectomy, which leads to postlaminectomy kyphosis in 15%-43% of cases, ODL is purported to reduce this adverse outcome. 2,3,5,16,28 Despite these advantages, reports have shown that ODL may lead to persistent neck and shoulder pain, progressive loss of ROM, and progressive cervical kyphosis. [6][7][8]11,29 There are various approaches used to perform cervical laminoplasty, many of which involve spinous process resection and disruption of intervening interspinales musculature and supraspinous ligaments (intraspinous and supraspinous ligaments [ISLs]). 5,9,20 Alternative methods have been reported that retain the dorsal ligamentous complex, and small cohorts have shown it may protect from loss of sagittal balance, while not statistically reducing cervical ROM. obJective Cervical open-door laminoplasty (ODL) is designed to decompress the spinal cord, maintain motion, and prevent postlaminectomy kyphosis. Many traditional laminoplasty techniques involve disruption of the posterior ligamentous structures, most notably the C7-T1 supraspinous ligament and interspinales muscle complex (intraspinous and supraspinous ligaments [ISLs]). methodS Eight human cervical cadaveric specimens (C2-T1) were used to investigate the subaxial kinematics following ODL with varying degrees of posterior element disruption. Ligamentous integrity was preserved and specimens were tested utilizing force control in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in the native state, and following 1) C3-7 ODL, 2) ODL with terminal ISL resection, 3) ODL with C3-7 spinous process resection, and 4) C3-7 laminectomy. Range of motion (ROM) was measured across C2-T1, "global," and at the segmental level. reSultS Compared with ODL, sectioning the terminal ISLs resulted in global ROM increases by 7.9% in FE, 2.4% in LB, and 5.6% in AR (p > 0.05), whereas laminectomy increased global ROM by 36.0% in FE (p = 0.002) and a 26.3% increase in AR ROM (p = 0.01). When considering segmental ROM, resection of the terminal ISLs increased ROM in FE by 36.5% at C2-3 (p = 0.019) and 25.4% at C7-T1 (p > 0.05). Segmental increases following C3-7 spinous process resection averaged less than 3% per level, compared with up to 40% increases in ROM per level after laminectomy. coNcluSioNS Laminectomy resulted in the greatest increase in global cervical ROM. Resection of the ISLs at C2-3 and C7-T1 increased segmental ROM at these specific levels to a similar extent that laminectomy increased ROM at each cervical level. This segmental ROM may contribute to pain or postprocedural deformity and highlights the importance of the ISLs at the terminal ends of the ODL.

Clinical and Radiographic Outcomes of Cervical Open-Door Laminoplasty Withmodified Centerpiece Mini-Plate Fixation and Extensor Attachment Point Reconstruction in Treating Cervical Spondylotic Myelopathy

“…In addition, the tension band generated by the posterior cervical muscles can still maintain cervical curvature. Moreover, the supporting point formed at the distal end of the titanium plate at the C3 and C7 segments can also increase the force arm length of the posterior cervical extensor muscles [8,15,20]. Muscle fatigue will not easily occur after frequent cervical exion and extension, which may explain the mild AS reported by patients in group A.…”

“…In patients with a short muscular neck, partial dissection of the semispinalis cervicis off of its C2 spinous process attachment is required in order to allow adequate opening of the vertebral laminae [6]. In addition, the removal of the spinous process before vertebral lamina opening also leads to the loss of a wide range of muscle attachment points, resulting in postoperative posterior cervical muscle atrophy, which further weakens the effect of anti-axial load and stretch stress and may lead to changes in the cervical curvature, decreased cervical stability, and increased incidence of postoperative axial symptoms [7][8].…”

Laminoplasty for Cervical Spinal Cord Stimulator Implantation in Patients With Cervical Spondylosis and Fusion: A Technical Note

“…4 Decompressing the spinal cord with a traditional laminectomy offers safe placement of the paddle lead but has the potential for long-term segmental instability and kyphotic deformity in 15%-43% of cases. 16 In addition, laminectomy has the potential to increase the risk of postoperative lead displacement because the bone that stabilizes the paddle lead in the epidural space has been removed. The significant mobility of the cervical spine contributes to higher rates of postoperative migration and breakage compared to the thoracic SCS, leading to long-term failure and revision rates of 22%-50% reported in large published series.…”

“…Although cervical laminoplasty has been associated with prolonged neck pain, loss of range of motion, and worsening cervical kyphosis, 18 preserving the supraspinous and interspinous ligaments at the distal ends of the laminoplasty may provide more stability than laminectomy. 16 The two laminoplasty techniques described provide a means to stabilize the lead paddle in the epidural space. 13 In addition, preservation of the lamina has been shown to reduce scar tissue formation.…”

Aggravation and subsequent disappearance of cervical disc herniation after cervical open-door laminoplasty

“…This decrease can lead to kyphosis of the cervical sagittal alignment. [ 9 ] Some authors reported that the abnormal cervical sagittal alignment was related to cervical disc degeneration and herniation. [ 10 – 12 ] An abnormal cervical sagittal alignment could increase the intervertebral disc pressure and change the transmission pattern of the cervical stress.…”