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Preliminary Clinical Study of Plate-only Laminoplasty for Multilevel Cervical Degenerative Disease: Can it Correct Cervical Malalignment?

Authors: Yu Chen, Dr., Yang Liu, Dr., Yu Chen, Dr., Li-li Yang, Dr., Wen Yuan, Dr.


Name and address of the department: Department of orthopaedic surgery, Changzheng hospital, Second Military Medical University, Huangpu district, Fengyang Rd No. 415, Shanghai, China. 

Address for Correspondence

Wen Yuan, Telephone number: 8613564441275, E-mail:

Li-li Yang, Telephone number: 8613020144327,



Study Design.

Clinical study of plate-only laminoplasty for patients with multilevel spinal degenerative diseases. Objectives. To demonstrate the efficacy of plate-only laminoplasty in correcting preoperative cervical malalignment.

Summary of Background Data.

Laminoplasty is regarded unsuitable to patients with preoperative cervical malalignment, postoperative complications such as C5 nerve root palsy and axial pain also hinder the application of thus surgical technique. Methods. The authors conducted pre and postoperative imaging assessment of 29 patients who underwent plate-only laminoplasty. Cervical alignment, C2-C7 and local kyphotic angles, and neurologic function status were evaluated.


Twenty-six patients (89.7%) experienced improved neurological status after surgery. Preoperative cervical malalignment was not correlated with postoperative neurologic recovery. Improvement of 6.1±5.2°in the cervical alignment was indicated in 21 patients (72.4%), and cervical range of motion was better preserved among the patients experiencing improved alignment postoperatively. Postoperative complications were rarely recorded.


Plate-only laminoplasty can provide reliable fixation. Preoperative flexible kyphotic deformity less than 10°and well preserved range of motion after surgery are responsible for postoperative correction in malalignment. Complications could be well prevented by thus surgical technique.

J.Orthopaedics 2012;9(3)e7


Laminoplasty; Cervical Malalignment; Complication; 


Open-door cervical laminoplasty, originally developed in Japan by Hirabayashi, has gained ever increasing popularity as the treatment of multilevel cervical spondylotic myelopathy (CSM), ossification of posterior longitudinal ligament (OPLL) and cervical spinal stenosis.1-3 A desired outcome after open-door cervical laminoplasty is reconstruction of a stable laminar arch with sufficient room for the decompressed spinal cord.4 The decompressive effects of laminoplasty comprise a direct posterior decompression, and an indirect anterior relief obtained by the posterior shift of the spinal cord from the anterior compressive lesions.5 However, complications such as hinge closure due to loss of fixation happen occasionally, followed by sudden exacerbation of neurologic functions, despite the surgeons’ attempts to introduce bone struts and artificial spacers into laminoplasty.6-9

The aforementioned unfavorable outcomes constituted the impetus of titanium plates as a relatively newer form of laminoplasty fixation.4 However, the currently reported clinical outcomes concerning plating in laminoplasty are scarce, and generally covered relatively short-term follow-ups.4, 10-13 Plate-only laminoplasty, namely laminoplasty combined with plating rather than bone grafts or spacers of any forms, has received ever-increasing attention among the diverse technical variations, because the construct is technically facile to insert, permitting early postoperative mobility, and obviates the possibility of hinge closure due to grafts dislodgement.4 However, cervical kyphosis is consistently viewed as a contraindication to laminoplasty, due to thus procedure’s ineffectiveness in decompression of the spinal cord and in restoration of the spinal alignment of an already kyphotic spine.10,14

Nevertheless, some authors demonstrated that laminoplasty, especially those assisted by plating, can provide sufficient decompression room for spinal cord even in kyphotic spines, and help maintain the cervical sagittal alignment.1, 15 These clinical outcomes have added uncertainty of laminoplasty as a management option for patients with cervical kyphosis, and no research has yet reported the effects of plate-only laminoplasty on correcting cervical malalignment. We applied plate-only laminoplasty to treat a series of cases with multilevel cervical degenerative disease, and evaluated its effects on spinal sagittal alignment correction..

Patients and methods:


Between September 2009 and January 2012, a total of 29 patients underwent plate-only laminoplasty in our institution. The records of these patients were reviewed pursuing an average 13-month (range, 6 to 15 months) follow-up. All patients had a diagnosis of compressive cervical myelopathy due to either spondylosis, OPLL, cervical spinal stenosis or a combination of these diseases.

The diagnosis was verified by history, physical examination, and imaging outcomes such as radiography and/or magnetic resonance imaging (MRI) and/or computed tomography (CT). The assessment of the patients was carried out by at least 2 certified surgeons of varying experience to ensure the reliability of the research.


Neurologic assessment

Neurologic statuses before and after surgery were evaluated using the Japanese Orthopedic Association (JOA) scores, Nurick classification system, and JOA recovery rate13, 16,17, which was calculated as follows: recovery rate (%) = (postoperative JOA score - preoperative JOA score)×100/(17 - preoperative JOA score). Poor surgical outcome was defined as a postoperative recovery rate less than 50%, and good outcome was defined as a recovery rate exceeding 50%.

Imaging assessment

The C2–C7 angle and local kyphotic angles were measured before surgery and at the end of the follow-up with the neutral and flexion-extension view of lateral radiography by Cobb method (Figure 1).16 Cervical alignment was determined on preoperative and postoperative neutral radiographs using a classification proposed by Kamata et al 1 Range of motion (ROM) between C2 and C7 was measured on flexion-extension radiographs taken before surgery and at the final follow-up (Figure 2).15 If dynamic flexion–extension radiographs demonstrate a reduction of deformity of more than 50% and CT scans demonstrate no segmental ankylosis, the cervical kyphosis will be defined as flexible kyphosis, or otherwise fixed kyphosis.18 The anteroposterior diameter of the spinal canal was measured on lateral neutral radiographs at the C4 mid-vertebral level. (Figure 3) Postoperative anteroposterior diameter was defined as the distance between the posterior aspect of the vertebral body and anterior border of the opened-side lamina that appeared as an oval or teardrop silhouette (Figure 3). Decompression status of the spinal cord was verified on MRI obtained at the final follow-up (Figure 3).5,17

Statistical analysis

Statistical analysis was performed to determine the relationship among different variables. All statistical procedures were performed using a commercially available software (SPSS version 10.0). P-values were calculated by using the Chi-square test or Fisher’s exact test for categorical variables, and by the Student’s t-test for continuous variables. Statistical significance was defined as p<0.05. All mean values were expressed as mean±standard deviation (SD).

Surgical Technique

The patient was positioned prone in bed and a standard posterior exposure of the cervical spine was carried out. A round burr was used to transect each lamina on one side at the junction of the lateral mass and lamina. On the contralateral side, a hinge was created by cutting a half-thickness through at the symmetrical location. By using a lamina elevator, the gap was expanded. With the lamina in expanded position, the miniplate (Arch, Synthes) of sufficient size allowing for adequate spinal canal expansion was selected by inserting the trial implants into the laminar gap. (Miniplates with 8-millimeter laminar gap were applied in all patients in the cohort, for their compatibility with Asians).

The double-bent miniplate was placed on the laminar expansion using the holder for miniplate and the best anatomical fit was determined. No bone grafts or spacers of any forms were applied as a strut between the lateral mass and the cut edge of the lamina. The first screw of proper size was placed immediately lateral to the gap. Centering the screw site on the lamina helped to prevent screw breakout along the laminar edges. Remaining screws were inserted subsequently. Two screws for each arm were used for fixation in all cases. The same procedure was repeatedly carried out in the remaining segments as required.


Statistical Analysis

Analysis of variance for repeated measures was performed to detect possible differences between the 3 treatment groups . The innersubject factor was time (preoperative, postoperative) and the intersubject factor was status (complete repair, partial repair, debridement). As post hoc comparison test, the least significant difference (LSD) pairwise multiple comparison test was used between the groups. We used the parametric paired t test to compare the pre- and postoperative values within the treatment groups. A significance level less than 0.05 was assumed. We used SPSS statistical software, version 12.0, for Windows, for all calculations. Unless specified otherwise, results are given as mean ± standard deviation.



Preoperative characteristics

The demographic and clinical features of the 29 patients were summarized in Table 1. There were 22 men and 7 women. Etiologies comprised cervical spondylosis in 10 patients, OPLL in 23 patients, and spinal canal stenosis in 12 patients. All patients had a diagnosis of myelopathy, and 12 patients had radiculopathy. The mean age at surgery was 62±8 years (range, 48 to 74 years) with a preoperative duration of 11±3 months (range, 6 to 19 months) from onset. Laminoplasty was performed from C3 –C7 in 24 patients, C2 –C6 in 3 patients, and C4-C7 in 2 patients, and the average number of enlarged laminae was 4.9 (range 4-5). Before surgery, the mean JOA score was 9.3±1.2, with Nurick grade 1 and 2 (24, 82.8%) most common. Four patients presented with flexible kyphosis indicated by radiographs and CT. Straight and s-shape malalignment were 10 and 1 respectively. The mean ROM was 26.4±11.7 °(range 7.0 to 49.7°),

Postoperative features

All of the 29 patients were available at the final follow-up. The mean operation time was 2.1±0.5 hours (range, 1.7 to 3 hours), and average blood loss was 251±53 ml (range, 203 to 350 ml). The average length of hospital stay was 134.4±25.3 hours (range 120 to 170 hours). Complications such as fifth nerve root palsy, premature hinge closure, loss of fixation, postoperative kyphosis, and axial pain were absent.

Decompressive outcomes and neurological status

A mean 4.2±2.0 mm expansion (range 1.4 to 7.2 mm) of anteroposterior diameter of the spinal canal was observed in all cases, and postoperative expansion rate was 31.8±23.0%. Postoperative MRI showed effective spinal decompression reflected by cerebrospinal fluid of hyperintensity around spinal cord in T2 weighted sagittal images. Twenty-six patients (89.7%) experienced improved neurological status after surgery. Fifteen patients (51.7%) presented with a good neurologic outcome measured by JOA recovery rate. Four patients experienced 2 Nurick grades improvement, and 19 patients improved by 1 grade, while 8 patients presented with unchanged grades. In patients with preoperative cervical lordosis, JOA recovery rate was 47.4%, no significant difference was observed compared with the recovery rate of 45.6% in patients with preoperative malalignment (p=0.067). (Table 2) Among patients with good neurological outcome, the preoperative period since onset of the symptom was 9.7 months, significantly shorter than that of 13.5 months in the poor neurologic outcome group (p=0.000).

Improvement of cervical alignment

Considering the total cervical alignment, no postoperative kyphotic deformity was observed, 11 patients’ alignment improved, of whom 1 S-shape malalignment became straight, 6 straight spines improved to be lordotic, 2 kyphosis became straight, and the other 2 kyphotic deformities became lordotic, the rest patients remained as preoperatively. Measured by C2-C7 Cobb angle/ local kyphotic angle, improvement of 6.1±5.2°was indicated in 21 patients, and no change was demonstrated in 6 patients, with deterioration being found in 2 patients. (Table 3) Lordosis was measured at 20.6±5.0°before surgery and 21.8±4.9°after surgery (p=0.063).

The local kyphotic angle of 8.3±2.1°was corrected to be -11.5±3.2°postoperatively (p=0.000). A mean 11.0±7.2°reduction of kyphotic angle (range 4.0 to 18.2°) was indicated. Mean age in the improved and unchanged/worsening alignment groups were similar (62 vs. 60 years, p=0.085). The mean reduction in cervical ROM after surgery was 1.6±1.7°. No significant difference was detected between pre and postoperative ROM (27.4 vs. 25.8°, p=0.084). Among patients who experienced improvement of alignment, a postoperative increase of 5.5±3.7°in ROM was noted, while in the unchanged or worsening group, a reduction of 4.0±2.9°in ROM was demonstrated (p=0.000). The postoperative ROM in the improved alignment group was 33.9±10.7°, significantly higher than that of 29.9±10.4°in unchanged or worsening alignment group (p=0.010).


in Cobb angle The Cobb angles of 2 patients exacerbated at the final follow-up. Both of them presented with preoperative lordotic alignment, the lordotic angles were 22.7and 18.6°respectively. After surgery, cervical alignment deteriorated to 14.8 and 10.6°, with a reduction of 8.0°in ROM. Additionally, their JOA recovery rate was measured 16.7% and 17.7%, and the Nurick grades both proved unchanged at the final follow-up. Preoperative period of the two patients were 18 and 20 months respectively, longer than the average length of time before surgery.lasty.



As an alternative to laminectomy for multilevel cervical degenerative compressive myelopathy, laminoplasty has received increased attention due to its similar rates of neurological improvement and much better preservation of spinal stability. 19-22 Its newer techniques updates have also become the focus of attention.6, 22 Plate-only laminoplasty has recently aroused wide interests among the surgeons, due to its favorable postoperative outcomes and low risks of complications.4, 13, 23 Rhee JM reported screw backout in patients undergoing plate-only open door laminoplasty at the final 12-month follow-up.4 In their series, such complication occurred only in those with one screw inserted on each side of the plate. All patients in our series received two inserted screws either in laminar arch or lateral mass, and no screw backout was observed. By inserting two screws on each side of the gap, postoperative fixation proved reliable. Nonetheless, longer term follow-up will be necessary to evaluate the reliability of the laminar arch reconstructed by plate-only laminoplasty.

In addition, double-bent miniplates rather than single-bent ones were applied in all patients, because the authors believe the miniplates of this feature were more suitable to the surgical regional anatomy. Postoperative complications such as C5 nerve root palsy and axial pain were absent in our cohort, we attribute the low complication rates to the following characteristics of the surgical technique:

1. The cervical vertebral lamina and paraspinal musculature were well preserved in plate-only laminoplasty, besides early cervical mobility permits better cervical muscular training, these factors probably helped reduce the occurrence of postoperative axial pain;

2. Miniplates of appropriate sizes were carefully chosen from the 5 size options, the plate with 8-millimeter laminar gap proved efficient either in spinal decompression or in preventing the over posterior shift of the spinal cord, which may induce C5 nerve root palsy.

Since there is no well recognized standards on hinge union after laminoplasty, and postoperative CT was not routinely performed in our cohort, evaluation of postoperative hinge union was not conducted. It's worth mentioning that a “healed” laminar arch reconstructed by plate-only laminoplasty was deemed unnecessary for neurological improvement and cervical mobility in the relevant research.4 Laminoplasty is widely regarded as contraindicated to cases with preoperative cervical malalignment, especially kyphosis, due to the possible compromised decompressive effects in this scenario. 1, 10, 15 Widely accepted is the notion that kyphosis could interfere with the postoperative decompression of the spinal cord, because the spinal cord had been compressed at the apex of the kyphotic spine, and its posterior shift is impaired, followed by poor surgical outcomes.10 Nevertheless, Kawakami M et al reported irrelevance between preoperative kyphosis and postoperative outcomes.17 We studied the JOA recovery rate in patients with preoperative lordosis and those with malalignment(47.4 vs. 45.6%), and found no significant difference between the two groups, incorporating the MRI findins, we suggested that postoperative decompression was sufficient in both groups.

We then assessed duration before admission, correlation of long preoperative delay and poor neurological outcomes was observed. Hence, preoperative duration may be an important indicator for neurological results after laminoplasty. However, there were only 4 kyphotic deformities of less than 10°in our cohort, the absence of marked malalignment might resulted in the seemingly favorable neurological outcomes in patients with preoperative cervical kyphosis. Although better preservation of cervical lordosis was reported since miniplates had been introduced into laminoplasty, no current research has demonstrated the corrective effects of laminoplasty on cervical malalignment, and articles concerning thus surgical procedures are rare.4, 24 Cervical kyphosis is an outcome of the unbalance between anterior and posterior cervical elements, and is traditionally divided into rigid and flexible types.

Rigid kyphosis is characterized by ankylosis of facet joints, vertebral osteophytes formation, and wedging of the vertebrae followed by a significant loss of cervical mobility; while a flexible kyphotic spine is much more mobile, and can be theoretically improved by dynamic factors such as a revived tension band (spinous process, ligamentous complex, and paravertebral muscles).25 In our series, 21 (72.4%) patients showed postoperative improvement in cervical Cobb angles to various extents. The four kyphotic deformities were corrected to be straight or lordotic. Notably, preoperative radiographs indicated that the kyphotic spines were flexible, and the kyphotic angles had been consistently less than 10°. These factors constituted the prerequisite for postoperative correction of cervical alignment. We also studied postoperative cervical ROM as a factor contributing to the improvement in cervical alignment after surgery. Plate-only laminoplasty permits early postoperative cervical mobility because bone healing on the open side is unnecessary and fixation is reliable on the elevated lamina. Hence long-term cervical bracing was avoided and cervical motion was encouraged.4

The authors educe early rehabilitation of tension band and relevant ligamentous/musculous structure is desirable in this situation, resulting in better preservation of cervical ROM. Reduction in ROM after laminoplasty was previously reported to be approximately 50% .26 Our research revealed better preserved ROM, and no significant difference was noted compared with preoperative ROM. Maeda T et al demonstrated that decrease in ROM after laminoplasty was significantly correlated with the decrease in cervical lordosis.27 We compared change in ROM between patients with improved alignment and those of unchanged/worsening alignment, a postoperative increase of 5.5°in the former group was observed, reversely, the latter group presented with a reduction of 4.0°; additionally, patients with improved alignment demonstrated significantly better preservation of ROM compared with the unchanged/worsening ones (33.9°vs. 29.9°). These results suggested that postoperative maintenance or correction of cervical alignment may possibly benefitted from the early and sufficient cervical motion provided by plate-only laminoplasty.

Intriguingly, the corrective effects on cervical alignment by plate-only laminoplasty were more obvious in patients with preoperative malalignment (kyphotic or straight alignment), as preoperative lordotic angles did not experience a significant improvement after surgery. Postoperative worsening spinal alignment after laminoplasty has been documented in previous researches.9, 28-30 Rather than postoperative kyphosis, we found 2 patients of preoperative cervical lordosis experienced deterioration of cervical alignment during follow-up. The significant reduction of ROM after surgery may be responsible for this sagittal compromise.


To our knowledge, this is the first report concerning alignment corrective effects of plate-only laminoplasty on patients with preoperative cervical malignment. Flexible kyphotic deformity of less than 10°is a prerequisite for postoperative correction in cervical malalignment. Using double-bent miniplates (secured by 4 screws), reliable fixation is achievable, which permits early cervical motion and well preserved ROM postoperatively, this benefit also played a significant role in correcting cervical malalignment. The unique features of thus surgical technique effectively prevented the occurrence of postoperative complications.


    1. Chiba K, Toyama Y, Watanabe M, Maruiwa H, Matsumoto M, Hirabayashi K. Impact of longitudinal distance of the cervical spine on the results of expansive open-door laminoplasty. Spine (Phila Pa 1976). 2000; 25(22): 2893-8.

    2. Tanaka J, Seki N, Tokimura F, Doi K, Inoue S. Operative results of canal-expansive laminoplasty for cervical spondylotic myelopathy in elderly patients. Spine (Phila Pa 1976). 1999; 24(22): 2308-12.

    3. Wang MY, Green BA. Open-door cervical expansile laminoplasty. Neurosurgery. 2004; 54(1): 119-23; discussion 23-4.

    4. Rhee JM, Register B, Hamasaki T, Franklin B. Plate-only open door laminoplasty maintains stable spinal canal expansion with high rates of hinge union and no plate failures. Spine (Phila Pa 1976). 2011; 36(1): 9-14.

    5. Sodeyama T, Goto S, Mochizuki M, Takahashi J, Moriya H. Effect of decompression enlargement laminoplasty for posterior shifting of the spinal cord. Spine (Phila Pa 1976). 1999; 24(15): 1527-31; discussion 31-2.

    6. Satomi K, Ogawa J, Ishii Y, Hirabayashi K. Short-term complications and long-term results of expansive open-door laminoplasty for cervical stenotic myelopathy. Spine J. 2001; 1(1): 26-30.

    7. Tanaka N, Nakanishi K, Fujimoto Y, Sasaki H, Kamei N, Hamasaki T, et al. Expansive laminoplasty for cervical myelopathy with interconnected porous calcium hydroxyapatite ceramic spacers: comparison with autogenous bone spacers. J Spinal Disord Tech. 2008; 21(8): 547-52.

    8. Wang MY, Shah S, Green BA. Clinical outcomes following cervical laminoplasty for 204 patients with cervical spondylotic myelopathy. Surg Neurol. 2004; 62(6): 487-92; discussion 92-3.

    9. Wada E, Suzuki S, Kanazawa A, Matsuoka T, Miyamoto S, Yonenobu K. Subtotal corpectomy versus laminoplasty for multilevel cervical spondylotic myelopathy: a long-term follow-up study over 10 years. Spine (Phila Pa 1976). 2001; 26(13): 1443-7; discussion 8.

    10. Park AE, Heller JG. Cervical laminoplasty: use of a novel titanium plate to maintain canal expansion--surgical technique. J Spinal Disord Tech. 2004; 17(4): 265-71.

    11. Shaffrey CI, Wiggins GC, Piccirilli CB, Young JN, Lovell LR. Modified open-door laminoplasty for treatment of neurological deficits in younger patients with congenital spinal stenosis: analysis of clinical and radiographic data. J Neurosurg. 1999; 90(2 Suppl): 170-7.

    12. Agrawal D, Sharma BS, Gupta A, Mehta VS. Efficacy and results of expansive laminoplasty in patients with severe cervical myelopathy due to cervical canal stenosis. Neurol India. 2004; 52(1): 54-8.

    13. Petraglia AL, Srinivasan V, Coriddi M, Whitbeck MG, Maxwell JT, Silberstein HJ. Cervical laminoplasty as a management option for patients with cervical spondylotic myelopathy: a series of 40 patients. Neurosurgery. 2010; 67(2): 272-7.

    14. Steinmetz MP, Resnick DK. Cervical laminoplasty. Spine J. 2006; 6(6 Suppl): 274S-81S.

    15. Ogawa Y, Toyama Y, Chiba K, Matsumoto M, Nakamura M, Takaishi H, et al. Long-term results of expansive open-door laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine. J Neurosurg Spine. 2004; 1(2): 168-74.

    16. Suda K, Abumi K, Ito M, Shono Y, Kaneda K, Fujiya M. Local kyphosis reduces surgical outcomes of expansive open-door laminoplasty for cervical spondylotic myelopathy. Spine (Phila Pa 1976). 2003; 28(12): 1258-62.

    17. Kawakami M, Tamaki T, Ando M, Yamada H, Yoshida M. Relationships between sagittal alignment of the cervical spine and morphology of the spinal cord and clinical outcomes in patients with cervical spondylotic myelopathy treated with expansive laminoplasty. J Spinal Disord Tech. 2002; 15(5): 391-7.

    18. O'Shaughnessy BA, Liu JC, Hsieh PC, Koski TR, Ganju A, Ondra SL. Surgical treatment of fixed cervical kyphosis with myelopathy. Spine (Phila Pa 1976). 2008; 33(7): 771-8.

    19. Emery SE, Bohlman HH, Bolesta MJ, Jones PK. Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy. Two to seventeen-year follow-up. J Bone Joint Surg Am. 1998; 80(7): 941-51.

    20. Onari K, Akiyama N, Kondo S, Toguchi A, Mihara H, Tsuchiya T. Long-term follow-up results of anterior interbody fusion applied for cervical myelopathy due to ossification of the posterior longitudinal ligament. Spine (Phila Pa 1976). 2001; 26(5): 488-93.

    21. Yonenobu K, Hosono N, Iwasaki M, Asano M, Ono K. Laminoplasty versus subtotal corpectomy. A comparative study of results in multisegmental cervical spondylotic myelopathy. Spine (Phila Pa 1976). 1992; 17(11): 1281-4.

    22. Hale JJ, Gruson KI, Spivak JM. Laminoplasty: a review of its role in compressive cervical myelopathy. Spine J. 2006; 6(6 Suppl): 289S-98S.

    23. Tsuzuki N. A novel technique for laminoplasty augmentation of spinal canal area using titanium miniplate stabilization: a computerized morphometric analysis. Spine (Phila Pa 1976). 1997; 22(8): 926-7.

    24. O'Brien MF, Peterson D, Casey AT, Crockard HA. A novel technique for laminoplasty augmentation of spinal canal area using titanium miniplate stabilization. A computerized morphometric analysis. Spine (Phila Pa 1976). 1996; 21(4): 474-83; discussion 84.

    25. Tani S, Suetsua F, Mizuno J, Uchikado H, Nagashima H, Akiyama M, et al. New titanium spacer for cervical laminoplasty: initial clinical experience. Technical note. Neurol Med Chir (Tokyo). 2010; 50(12): 1132-6.

    26. Ratliff JK, Cooper PR. Cervical laminoplasty: a critical review. J Neurosurg. 2003; 98(3 Suppl): 230-8.

    27. Maeda T, Arizono T, Saito T, Iwamoto Y. Cervical alignment, range of motion, and instability after cervical laminoplasty. Clin Orthop Relat Res. 2002; (401): 132-8.

    28. Edwards CC, 2nd, Heller JG, Silcox DH, 3rd. T-Saw laminoplasty for the management of cervical spondylotic myelopathy: clinical and radiographic outcome. Spine (Phila Pa 1976). 2000; 25(14): 1788-94.

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    30. Matsunaga S, Sakou T, Nakanisi K. Analysis of the cervical spine alignment following laminoplasty and laminectomy. Spinal Cord. 1999; 37(1): 20-4.

    Figure 1.


Figure 1. The difference in the C2-C7 angles before and after surgery. (A) Preoperative C2-C7 angle measured 6.4°of lordosis, and C3-C6 angle measured 8.6°of kyphosis. (B) Postoperative C2-C7 angle measured 20.8°of lordosis, and C3-C6 angle measured 1.7°of kyphosis.

Figure 2.

Figure 2. The range of motion (ROM) between C2 and C7 was measured on flexion-extension radiographs. The difference in the angles between the lines drawn parallel to the posterior aspects of C2 and C7 vertebral bodies on flexion and extension radiographs is defined as C2–C7 ROM .

Figure 3.


Figure 3. A 61-year-old man who had severe cervical myelopathy caused by cervical ossification of posterior longitudinal ligament. Expansive laminoplasty was performed from C2 to C6. (A) Preoperative lateral neutral radiograph showing that anteroposterior canal diameter was 1.1 centimeters. (B) Postoperative lateral neutral radiograph showing that anteroposterior canal diameter was 1.7 centimeters. The JOA score improved from 7 points to 15 points, and the recovery rate was 80%. (C, E)Preoperative magnetic resonance image showing that the spinal cord is compressed at multiple levels. (D, F) Postoperative magnetic resonance image showing that the anterior aspect of the spinal cord is decompressed.

Table 1. Demographic and Clinical Features of the Patients Before Surgery

                                                        Pts. (%)


22 (76)



Cervical Spondylosis


Ossification of Posterior Longitudinal Ligament  


Spinal Canal Stenosis


Mean Age at Surgery (year)


Preoperative Duration (month)


Mean Number of Decompressed Segments


JOA Score


Nurick Grade 1 and 2

24 (82.8)

Cervical Malalignment

15 (52)

Flexible Kyphosis

4 (18)

Rigid Kyphosis

Straight Malalignment

10 (34)

 S-shape Malaignment 

1 (3)

Mean Rang of Motion (degree)


JOA=Japanese Orthopedic Association

Table 2. Relation Between JOA Recovery Rate and Preoperative Cervical Malalignment


JOA Recovery Rate (%)

Preoperative Cervical Lordosis


Preoperative Cervical Malalignment


Significant relation: p>0.05 based on Chi square test.

Table 3. Postoperative Changes in Cervical Alignment

                                          Pts. (%)

Postoperative Improvement

21 (72)

No change

6 (21)

Postoperative Deterioration

2 (7)

Measured by C2-C7 Cobb angle/ local kyphotic angle.

Table 4. Relation Between Range of Motion and Cervical Alignment


Patients Experiencing Improvement of Cervical Alignment 

Patients with no Improvement of Cervical Alignment


Postoperative Change in ROM (Degree)




Postoperative ROM





ROM=Range of motion. P-Value is based on Student’s t-test.







This is a peer reviewed paper 

Please cite as :

J.Orthopaedics 2012;9(3)e7




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