Efficacy and Results of Expansive Laminoplasty in Patients with Severe Cervical Myelopathy Due to Cervical Canal Stenosis

Original Article

Efficacy and results of expansive laminoplasty in patients with severe cervical myelopathy due to cervical canal stenosis

D. Agrawal, B. S. Sharma, A. Gupta, V. S. Mehta Department of Neurosurgery, Neurosciences center, All India Institute of Medical Sciences,New Delhi - 110029, India.

Aims and objectives: To assess the efficacy and results of caused by multisegmental cervical spondylosis (MSCS) or ossi- expansive laminoplasty in advanced (Nurick’s Grade III or fication of the posterior longitudinal ligament (OPLL). Cervi- greater) cervical myelopathy. Materials and Methods: We cal laminectomy and laminoplasty have been used to decom- reviewed data in 24 patients who underwent cervical press the neural elements posteriorly when there is extensive laminoplasty from January 1999 to December 2002. Nuricks involvement of the cervical spine. 1 Laminoplasty, which pre- grading was used for quantifying the neurological deficits serves the posterior elements, is considered the preferred pos- and outcome analysis was done using Odom’s criteria. A terior procedure.2-6 However, there have been no large series modified Hirabayashi’s open door laminoplasty was done with patients having clinically advanced disease. We analyze using Titanium miniplates and screws in 22 patients, autolo- our experience with this procedure in patients with symptoms gous bone in one and hydroxyapatite spacer in one patient. of severe cervical myelopathy, done over a four-year period. Observations: There were 3 females and 21 males with a mean age of 56 years (range 39-72 years). Four patients Materials and Methods presented in Nuricks Grade III, 15 in Grade IV and five in Grade V. MR imaging showed MSCS in 21 cases, OPLL in In this retrospective study, all patients who were admitted and nine cases and ligamentum flavum hypertrophy in nine cases underwent laminoplasty in the department of neurosurgery, from with cord signal changes being present in 19 cases. January 1999 through December 2002 (four-year period) were in- Results: All patients with duration of symptoms less than cluded. The demographic and clinical details, radiological investiga- three years, and 50 % with duration ranging from three to tions, operation details at admission and at follow-up were analyzed. six years had improvement by at least one Nurick’s grade following surgery. Eighty-seven per cent Grade IV patients Operative technique (ambulatory with support) improved to Grade III (ambula- Patients were operated under general anesthesia using endoscopic tory without support) following laminoplasty. Using Odom’s intubation to prevent neck extension, positioned prone with the head criteria, 23 patients (95.8%) had a good to fair outcome. in neutral position on a horseshoe. A standard posterior midline ap- Conclusions: Cord decompression with expansive proach with exposure of cervical laminae from C2 to C7 and laterally laminoplasty using titanium miniplate fixation may improve to the medial aspect of the facet joints was performed in all cases. the neurological outcome even in patients presenting late, Patients had undergone expansive laminoplasty with various modifi- and improvement by even one grade may have major ‘qual- cations. Twenty-two patients underwent a modified open door 3 ity of life’ benefits for these patients. laminoplasty originally described by Hirabayashi, modified and popu- larized using titanium miniplates and screws by O’Brien.7 Briefly, Key Words: Cervical canal stenosis, Laminoplasty, Ossifi- the technique involves making bony gutters laterally in the lamina at cation of the posterior longitudinal ligament, Ligamentum its junction with the facet joint, using a high-speed drill. One gutter flavum hypertrophy. (on the side of maximum compression) is deepened across the thick- ness of the laminae, and the spinous processes and laminae are pushed laterally towards the opposite side like an open door, so that the spinal canal is enlarged. To prevent the laminar door from closing, Introduction titanium miniplates, bent in a ‘Z’ shape are screwed to the laminae and/or spinous processes on one side and to the pedicle on the other side using appropriately sized titanium screws. However, on the hinge Cervical canal stenosis is caused by the narrowing of the cen- side, where the adjacent lamina and lateral masses are still connected, tral spinal canal or neural foramina and may be either develop- the dorsal cortex of these structures are bought into contact as the mental in origin, or secondary to bony and/or soft tissue changes hinge side trough is closed during elevation and rotation of the pos-

B. S. Sharma Department of Neurosurgery, Neurosciences center, All India Institute of Medical Sciences, New Delhi - 110029, India. E-mail: [email protected]

54 Neurology India March 2004 Vol 52 Issue 1 54 CMYK Agrawal D, et al: Expansive laminoplasty in advanced cervical myelopathy terior elements into the open position. One patient underwent Itoh’s Radiology modification of Hirabayashi’s technique,8 in which bone graft from Cervical spine X-rays were available in 14 patients and the rib was inserted to prevent closure of the hinged laminae. One showed degenerative changes in all (Figure 1a). OPLL was patient underwent a modified Hirabayashi laminoplasty in which visualized in six cases. Two cases showed evidence of fluoro- hydroxyapatite ‘spacers’ were placed and fixed using nylon sutures. sis. All patients underwent MR imaging (Sonata 1.5T, Sie- A soft collar was used during the first few days after surgery. No other external orthosis was used after surgery. mens, Erglen, Germany) which showed MSCS in 21 cases, OPLL in nine cases and ligamentum flavum hypertrophy in Observations nine cases. Thirteen patients had five levels, nine patients had four levels and two patients had six levels involvement. Purely Demographic profile anterior compression was present in 15 (62.5%) patients and There were 21 males and 3 females yielding an M: F ratio of both anterior and posterior compression was present in 9 7:1. Their ages ranged from 39 to 72 years with a mean of (37.5%) patients (Figures 1b and 1c). There was no case with 56.73 years. Five patients had associated medical disorders (three had diabetes, one had hypertension and one had both diabetes and hypertension).

Clinical features Stiffness and gait disturbances were the commonest presenting symptoms seen in all the 24 (100%) patients. All patients had evidence of myelopathy in the form of spastic quadriparesis (one patient had Grade 5 power, 14 had Grade 4, three had Grade 3 power and in two patients power could not be assessed due to severe spasticity). Neck pain was seen in 11(45.8%) of the patients and sensory loss to touch, pain and temperature was present in 12 (50%) patients. Bladder disturbances were present in 11 (45.8%) patients. The duration of symptoms varied from two months to 96 months with 1a a mean of 30.5 months (Table 1). We used Nuricks grading for the quantification of neurological deficits and for correla- tion with cord signal changes on MRI (Table 2). Four patients presented with Nuricks Grade III, 15 in Grade IV and five in Grade V. Cord signal changes were present in 19 patients. One patient in Nuricks Grade III, 13 patients in Nuricks Grade IV and five patients in Nuricks Grade V had cord signal changes (Table 3) (Figure 1c).

Table 1: Duration of symptoms and cord changes Duration of Number of patients Cord changes symptoms (months) 0-4 2 0 4-12 7 4 12-36 9 9 36-72 4 4 1b 1c 72-96 2 2 Figures 1a - 1c: Preoperative X-ray cervical spine (1a), MRI cervical spine, axial section (1b) Figures 1c: Saggital section of a patient having Table 2: Nurick’s classification of disability severe cervical myelopathy Grade 0 Root signs and symptoms No evidence of cord involvement Table 3: Improvement in Nurick’s grade Grade I Signs of cord involvement Normal gait Nurick’s grade Preoperative Postoperative Grade II Mild gait involved (no. of pts) (no. of pts) Able to be employed GRADE 1 0 1 Grade III Gait abnormality prevents employment but GRADE 2 0 2 Ambulant without support GRADE 3 4 14 Grade IV Able to ambulate with assistance GRADE 4 15 6 Grade V Chair-bound or bedridden GRADE 5 5 1

Neurology India March 2004 Vol 52 Issue 1 55 CMYK 55 Agrawal D, et al: Expansive laminoplasty in advanced cervical myelopathy purely posterior compression. Cord changes were present in 19 cases. In 12 cases MRI films were available for the assessment of the cord changes. Of these 12 cases, 11 patients had cord changes only on T2 weighted images and one patient had cord changes on both T1 and T2 weighted images.

Operating time The average operating time was 187.67 minutes (range 90- 360 min) and the average blood loss was 716.67 ml (range 100-1400 ml).

Complications One patient on whom laminoplasty was done using hydroxyapatite spacers deteriorated in motor power from grade 4/5 to 2a grade 1/5 in the immediate postoperative period. A repeat MRI showed graft slippage causing cord compression. Re-exploration and removal of grafts resulted in improvement in motor power back to preoperative status. CSF leak occurred in one patient, which resolved on con- servative management. There was no mortality in this series.

Follow-up The average follow-up in 18 patients was 22 months and ranged from 6 months to 46 months. Six patients were lost to follow-up. All patients had cervical spine X-rays in the immediate postoperative period to see for plate and screw displace- ment. Two patients had CT cervical spine in the immediate postoperative period—in one case the hydroxyapatite spacers were seen compressing the theca and required re-exploration. In the second case the screws and plates were in position and 2b the open-door position of the laminae was well maintained Figures 2a and 2b: CT cervical spine axial (2a) and sagittal (2b), (Figures 2a and 2b). postoperative images showing the screws and plates in position and the open-door position of the lamina Results All patients with duration of symptoms less than three years, and 50 % of the patients with duration of symptoms ranging Three patients in Nurick’s Grade III improved to either from three to six years had improvement by at least one Nurick’s Grade I (n=1) or Nurick’s Grade II (n=2) follow- Nurick’s grade following surgery (Figure 3). However, patients ing the laminoplasty. Thirteen out of the 15 patients (86.6%) with duration of symptoms more than six years did not show who were in Grade IV (ambulatory with support) improved to any improvement in Nurick’s grade following surgery. Nurick’s Grade III (ambulatory without support) Patients who had cord signal changes on both T1 and T2 postoperatively. Surprisingly, four of the five patients (80%) weighted images on MRI had a poorer prognosis compared to in Nurick’s Grade V had improved to Grade IV following the patients who had cord signal changes only on T2 weighted laminoplasty, at last follow-up. Outcome assessment was done images. Patients having cord signal changes only on T2 using Odom’s criteria (Table 4) and using these criteria, 23 weighted images improved by at least one Nurick’s grade, com- patients (95.8%) had a good to fair outcome. pared to patients having cord signal changes on both T1 and T2 weighted images, who did not show any improvement in Table 4: Odom’s criteria Nurick’s grade following the laminoplasty. Excellent: All preoperative symptoms relieved; abnormal findings improved. Discussion Good: Minimal persistence of preoperative symptoms; abnormal findings unchanged or improved Fair: Definite relief of some preoperative symptoms; Anterior and posterior decompression are established tech- other symptoms unchanged or slightly improved niques in the management of multilevel cervical canal steno- Poor : Symptoms and signs unchanged or exacerbated. sis resulting in myeloradiculopathy.9-12 In the past, laminec-

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to maintain the ‘open’ book position of the posterior elements during laminoplasty. These are often complicated, requiring tedious wiring and bone-grafting techniques that increase the Preop operative time, blood loss, donor site pain and infection, be- 5 Postop Grade 5 1 sides increasing the technical difficulty. These considerations 15 could easily outweigh the possible benefits of laminoplasty over Grade 4 6 laminectomy. Titanium miniplate fixation, originally per- 4 Grade 3 14 formed by O’Brien, offers all the advantages of laminoplasty without its drawbacks and offers a simple, durable and effi- Grade 2 2 cient technique to maintain the postoperative position of the Grade1 1 open door.7 However, specific indications and contraindications for performing laminoplasty (Tables 5 and 6) have been de- 0 5 10 15 20 scribed and patient selection remains important for the suc- Number of patients cess of the procedure.6 Long-term results are also now available on laminoplasty. Figure 3: Pre and postoperative Nurick’s grade Iwasaki M, 4 studied 64 patients with OPLL who underwent expansive laminoplasty for more than 10 years (mean follow- tomy had been the most common method to achieve posterior up 12.2 years) and found that the neurological recovery was decompression of the cervical spine in these patients. How- maintained in 60% of the patients. Kyphosis was present in ever, the procedure was complicated by postoperative insta- 8% of the patients, although it was not found to be associated bility resulting in deformity, particularly kyphosis,9,11,12 as well with neurological deterioration. The authors recommended as postoperative laminectomy membrane formation resulting expansive and extensive laminoplasty for OPLL. Inoue H, 5 in restenosis and arachnoiditis.3 Anterior cervical decompres- studied long-term outcome (greater than 5 years) in patients sion with spinal fusion is also practiced widely in patients with with myelopathy due to cervical spondylosis and OPLL who cervical spondylotic myeloradiculopathy.13 However, a conse- underwent expansive laminoplasty, and complete decompres- quence of this procedure is the immobilization of multiple seg- sion was maintained in 84% of the patients with myelopathy ments, which has been shown to lead to long-term changes at due to cervical spondylosis. The average follow-up in our se- adjacent vertebral levels.14 Laminoplasty was developed to ries was 22 months, which is relatively short to give long-term avoid these complications, with the first expansive open door results. However, as all patients in our study had an advanced laminoplasty being described by Hirabayashi et al,3 and which disease at presentation, the results are significant. Postop- since than has been further modified by Hirabayashi and oth- erative improvement was also maintained in all our patients ers.7,15 The elegance of this procedure lies in its simplicity with at the last follow-up. results comparable to laminectomy and anterior decompres- Quantification of deficits for assessing the results of the sion. Itoh and Tsuji,7 besides others, have shown increased spinal surgery is also important and Nurick, in 1972, devised stability, with less sliding, tilting, and range of motion after a classification for cervical spondylotic myelopathy, largely laminoplasty compared with laminectomy. This may be pro- based on gait disturbances (Table 2). 16 The overwhelming ap- tective against postoperative instability. peal of this classification lies in its simplicity and that it can Various modifications have been advised by various authors be applied easily to retrospective data. For this reason Nurick’s classification was chosen for the quantification of deficits in Table 5: Indications for laminoplasty this study. However, as it is based mainly on gait abnormali- OPLL over multiple levels (with maintained cervical lordosis) ties, sensory deficits as well as bladder dysfunction are not Congenital canal stenosis (with maintained cervical lordosis) considered and remain important limitations. Though the JOA Multilevel cervical spondylosis (with maintained cervical scale overcomes these limitations, it is more complex and can- lordosis) 17 Posterior compression from ligamentous hypertrophy (with not be applied easily to retrospective data. maintained cervical lordosis) For outcome analysis we used the Odom’s scale,18 as it is the As part of a staged anterior and posterior canal expanding most commonly used scale and is relatively simple (Table 4). procedure Using Odom’s criteria, 23 patients (95.8%) had good to fair outcome (improvement by at least one grade) in the immedi- Table 6: Contraindications for laminoplasty ate postoperative period and the improvement was continu- Isolated radiculopathy ing or sustained at the last follow-up. More importantly, 13 Loss of anterior column support resulting from tumor, trauma, or infection out of 15 patients (86.6%) who were in Grade IV (ambula- Focal anterior compression tory with support) became ambulatory without support (Grade Established, absolute kyphosis III). This shows that improvement by even one grade may

Neurology India March 2004 Vol 52 Issue 1 57 CMYK 57 Agrawal D, et al: Expansive laminoplasty in advanced cervical myelopathy have major ‘quality of life benefits’ for these patients. An- and myeloradiculopathy by means of the posterior approach. Spine 1988;13: 864-9. other interesting finding of our study was the postoperative 3. Hirabayashi K, Watanabe K, Wakano K, Suzuki N, Satomi K, Ishii Y. Expan- improvement by at least one Nurick’s grade in 50 % percent sive open door laminoplasty for cervical spinal stenotic myelopathy. Spine 1983;8:693-9. of the patients with duration of symptoms between three and 4. Iwasaki M, Kawaguchi Y, Kimura T, Yonenobu K. Long-term results of expan- six years. This implies that the disease process may be par- sive laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine: more than 10 years follow up. J Neurosurg 2002;96:180-9. tially reversible, even in patients presenting late, though early 5. Inoue H, Ohmori K, Ishida Y, Suzuki K, Takatsu T. Long-term follow up re- surgery carries the best prognosis. view of suspension laminotomy for cervical compression myelopathy. J Neurosurg 1996;85:817-23. Our study assumes significance in view of the fact that the 6. Shaffrey CI, Wiggins GC, Piccirilli CB, Young JN, Lovell LR. Modified open- majority (80%) of the patients were in Nurick’s Grade IV or door laminoplasty for treatment of neurological deficits in younger patients with congenital spinal stenosis: analysis of clinical and radiographic data. J V, implying having advanced disease. Laminoplasty was found Neurosurg 1999;2:170-7. to be especially beneficial in these patients as almost all showed 7. O’Brien MF, Peterson D, Casey AT, Crockard HA. A novel technique for laminoplasty augmentation of spinal canal area using titanium miniplate neurological improvement with minimal morbidity and no stabilization: A computerized morphometric analysis. Spine 1996;21:474-84. mortality. 8. Itoh T, Tsuji H. Technical improvements and results of laminoplasty for compressive myelopathy in the cervical spine. Spine 1985;10:729-36. 9. Herman JM, Sonntag V. cervical corpectomy and plating for post laminectomy Conclusion kyphosis. J Neurosurg 1994;80:963-70. 10. Nakano N, Nakano T, Nakano K. comparison of the results of laminectomy and open-door laminoplasty for cervical spondylotic myeloradiculopathy and This is one of the largest studies on patients presenting with ossification of the posterior longitudinal ligament. Spine 1988;13:792-4. 11. Takayasu M, Takagi T, Nishizawa T, Osuka K, Nakajima T, Yoshida J. Bilat- severe cervical myelopathy and shows that cord decompres- eral open-door cervical e xpansive laminoplasty with hydroxyapatite spacers and sion using expansive laminoplasty using titanium miniplate titanium screws. J Neurosurg 2002;96:22-8. fixation may improve the neurological outcome even in pa- 12. Tani S, Isoshima ANagashima Y, Tomohiko NR, Abe T.Laminoplasty with Pres- ervation of Posterior Cervical Elements: Surgical Technique; Neurosurgery tients presenting late, and improvement by even one grade 2002;50:97-102. may have major ‘quality of life benefits’ for these patients. 13. Samii M, Volkening D, Sepehrnia A, Penkert G, Baumann H. Surgical treatment of myeloradiculopathy in cervical spondylosis: a report on 438 opera- Expansive laminoplasty using titanium miniplate fixation of- tions. Neurosurg Rev 1989;12:285-90. fers all the advantages of laminectomy without its drawbacks 14. Baba H, Furusawa N, Imura S, Kawahara N, Tsuchiya H, Tomita K. Late radiographic findings after anterior cervical fusion for spondylotic myelora- and offers a simple, durable and efficient technique to main- diculopathy. Spine 1993;18:2167-73. tain the postoperative open-door position , especially in pa- 15. Hirabayashi K, Satomi K. Operative procedure and results of e xpansive open- door laminoplasty. Spine 1988;13:870-6. tients with advanced disease. 16. Nurick S: The pathogenesis of the spinal cord disorder associated with cervical spondylosis. Brain 1972;95:87-100. 17. Hirabayashi K, Miyakawa J, Satomi K, Maruyama T, Wakano K. Operative References results and post operative progression of ossification among patients with ossification of cervical posterior longitudinal ligament Spine 1981;6:354-64. 1. Crandall H, Gregorius FK. Long term follow-up of surgical treatment of cervi- 18. Odom GL, Finney W, Woodhall B. Cervical disc lesions. JAMA 1958;166:223-8. cal spondylotic myelopathy. Spine 1977;2:139-46. 2. Epstein JA. The surgical management of cervical spinal stenosis, spondylosis Accepted on 02.12.2003

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