J Neurosurg Spine 20:1–4, 2014 ©AANS, 2014
C-5 palsy after cervical laminoplasty with instrumented posterior fusion Clinical article Kazuhiro Yamanaka, M.D., Toshiya Tachibana, M.D., Ph.D., Tokuhide Moriyama, M.D., Ph.D., Fumiaki Okada, M.D., Ph.D., Keishi Maruo, M.D., Ph.D., Shinichi Inoue, M.D., Ph.D., Yutaka Horinouchi, M.D., and Shinichi Yoshiya, M.D., Ph.D. Department of Orthopaedic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan Object. Postoperative C-5 palsy is known as a common complication after cervical laminoplasty. The authors of this article have encountered postoperative C-5 palsy more often when laminoplasty was combined with instrumented posterior spinal fusion than when it was performed alone. The purpose of this clinical study was to examine the incidence of fifth cervical nerve root palsy (C-5 palsy) and surgical results in patients with cervical myelopathy who had undergone laminoplasty with or without instrumented spinal fusion. Methods. The authors retrospectively studied patients with cervical myelopathy who had undergone laminoplasty with or without instrumented posterior spinal fusion. Results. Clinical data on 58 patients were evaluated and analyzed. Preoperative diagnoses were cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament of the cervical spine. Twenty-four patients with spondylolisthesis or kyphosis underwent laminoplasty combined with posterior spinal fusion using instrumented lateral mass fixation (fusion group), while the remaining 34 patients underwent laminoplasty without posterior spinal fusion (no-fusion group). In the fusion group, C-5 palsy developed in 6 patients; in the no-fusion group, it occurred in only 1 patient. There was a significant difference in the rate of this complication between the 2 groups. In the fusion group, local kyphosis and spondylolisthesis level were reduced at the fusion level, and all patients with C-5 palsy underwent C4–5 spinal fusion. Conclusions. The incidence of postoperative C-5 palsy is significantly higher after laminoplasty when it is combined with spinal fusion. Correction of kyphosis and spondylolisthesis using posterior instrumentation may be a risk factor for iatrogenic intervertebral foraminal stenosis leading to C-5 palsy. (http://thejns.org/doi/abs/10.3171/2013.9.SPINE12952)
Key Words • C-5 palsy • laminoplasty • posterior fusion • cervical myelopathy
L
aminoplasty is a surgical option widely used for cervical myelopathy. Authors of a number of clinical studies have examined the results of this surgical procedure by analyzing the factors influencing outcome. Among the pinpointed factors is cervical kyphosis, which is related to a poor prognosis because the spinal cord is not well decompressed in the kyphotic spine.11,16 Cervical spondylolisthesis is regarded as another factor affecting outcome, accompanied by progressive instability of the cervical spine after surgery. Therefore, we have performed reduction and fusion with instrumentation
Abbreviations used in this paper: JOA = Japanese Orthopaedic Association; MMT = manual muscle test; ROM = range of motion.
J Neurosurg: Spine / Volume 20 / January 2014
concomitant with laminoplasty for cervical myelopathy patients presenting with cervical spondylolisthesis or cervical kyphosis. Among the complications following cervical laminoplasty is fifth cervical nerve root palsy, which has been reported as one of the most frequently encountered problems.2,3,8,10–12,14,15,18,19 In our experience, C-5 palsy occurs after laminoplasty more often when the procedure is combined with posterior spinal fusion. We hypothesized that concomitant reduction of kyphosis or spondylolisthesis and spinal fusion is a risk factor for C-5 palsy after cervical laminoplasty, and that there may be some issues associated with the occurrence of this complication. To test this hypothesis, we reviewed our experience with postoperative C-5 palsy in patients 1
K. Yamanaka et al. who had undergone laminoplasty with and without instrumented spinal fusion. Additionally, we analyzed the clinical features of patients with this complication to clarify the pathological mechanism.
Methods
The local ethics committee authorized this study. We collected from our departmental database all cases treated using laminoplasty with or without instrumented posterior cervical spine fusion in the period from 1998 to 2004. In the clinical evaluation, the incidence of C-5 palsy after surgery and the subsequent recovery process were reviewed on patient charts. Clinical scores were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy2 both pre- and postoperatively, and the postoperative recovery rate was calculated as follows: (postoperative JOA score - preoperative JOA score) × 100/(17 - preoperative JOA score).6 In the radiological examination, the postoperative change in cervical kyphosis/lordosis was assessed according to the difference in the C2–7 angle in the neutral position. Range of motion (ROM) of the cervical spine was calculated using the change in the C2–7 angle from maximum flexion to extension positions. In the fusion group, the fusion level as well as the postoperative change in local kyphosis and spondylolisthesis was assessed on radiographs. Thereafter, comparative analysis was performed between the groups using these parameters. Moreover, CT was used to measure the width of the intervertebral foramen at C4–5 in the fusion group. The CT images were acquired in the intervertebral disc. The width of the C4–5 foramen was measured at its narrowest point. In the analysis of potential factors influencing the occurrence of C-5 palsy, the prognostic predictive value was assessed using logistic regression analysis for the following parameters: postoperative change in the C2–7 angle in the neutral position, ROM in the cervical spine, and presence of high intensity areas in the cervical spinal cord on T2-weighted MR images. In the statistical analysis to detect differences between groups, the Student t-test was performed using Excel (Microsoft Corp.), whereas chi-square analysis, Fisher exact test, and logistic regression analysis were performed using SPSS software (SPSS Inc.). A p value < 0.05 was considered to indicate significance.
Results
Fifty-eight consecutive patients who had undergone laminoplasty with or without instrumented posterior spinal fusion in the period from 1998 to 2004 were included in this study. Bilateral midsagittal-splitting open-door laminoplasty with or without lamina spacers5,16 was performed as an isolated procedure in 34 patients (no-fusion group), whereas laminoplasty without lamina spacers was supplemented with instrumented posterior spinal fusion using lateral mass screws in the remaining 24 patients (fusion group). In the no-fusion group, 28 patients underwent laminoplasty without lamina spacers; the procedure was 2
switched to laminoplasty with the use of lamina spacers for 6 patients in the later study period. All patients in the fusion group received autogenous bone grafts using local bone. Regarding instrumentation in the fusion group, the Olerud rod system was used in 9 cases and the Axis plate system in 15 cases. No patient in either group underwent foraminotomy. Neither was electrophysiological monitoring performed in any of the patients. Preoperative diagnoses were cervical spondylotic myelopathy in 39 patients and cervical ossification of the posterior longitudinal ligament in 19. Concomitant posterior spinal fusion was performed when spondylolisthesis (more than 3 mm) or local kyphosis (more than 3°) was present. All patients were followed up for more than 1 year. There were no significant differences in the average age at surgery, average follow-up period, sex distribution, or diagnosis between the groups (Table 1). In the fusion group, the average JOA score before surgery was 8.6 ± 2.8. At the latest follow-up, the average score increased to 12.6 ± 3.1, and the recovery rate was 52.6%. In the no-fusion group, the average JOA score before surgery was 9.0 ± 2.4. The average score increased to 13.4 ± 2.0 at the latest follow-up, and the recovery rate was 56.5%. Although significant postoperative improveTABLE 1: Summary of data in 58 patients who underwent cervical laminoplasty* Parameter
Fusion
total no. of patients 24 mean age at surgery in yrs (range) 63.0 (36–81) M/F 15/9 mean FU in mos 49 no. of patients w/ CSM 14 no. of patients w/ OPLL 10 JOA score preop 8.6 ± 2.8 latest FU 12.6 ± 3.1 recovery rate 52.6% C-5 palsy yes 6† no 18 time to recover from C-5 palsy (no. of patients) wks 2 mos 3 patients w/ permanent palsy 1 change in overall alignment in cervical spine (º) preop 4.7 ± 10.6† postop 4.5 ± 10.5 change in ROM in cervical spine (º) preop 31.6 ± 12.5 postop 15.9 ± 11.6
No Fusion 34 62.7 (40–83) 23/11 39 25 9 9.0 ± 2.4 13.4 ± 2.0 56.5% 1† 33
1 0 0
17.3 ± 13.9† 10.5 ± 18.4 35.2 ± 12.0 9.2 ± 10.2
* CSM = cervical spondylotic myelopathy; FU = follow-up; OPLL = ossification of the posterior longitudinal ligament. † Significant difference between the groups (p < 0.05).
J Neurosurg: Spine / Volume 20 / January 2014
C-5 palsy after cervical laminoplasty with posterior fusion ment in the clinical score was detected in both groups, there was no significant difference in the score at the final follow-up between the groups (Table 1). Among the 24 patients in the fusion group, C-5 palsy developed in 6, while only 1 patient among the 34 in the no-fusion group had C-5 palsy, thus demonstrating a significant difference in the incidence between the groups (p < 0.05; Table 1). Of the 6 patients with C-5 palsy in the fusion group, 2 had OPLL and 4 had CSM, while 1 patient with C-5 palsy in the no-fusion group had OPLL. No significant relationship was demonstrated between preoperative diagnosis and the rate of C-5 palsy postoperatively. Muscle weakness according to the manual muscle test (MMT) was Grade 4 in 2 patients, Grade 3 in 3 patients, and Grade 2 in 2 patients. During the subsequent time course in the 7 patients with C-5 palsy, muscle strength was recovered to an MMT Grade 5 within a few weeks in 3 patients and in 3–6 months in 3 patients; the palsy remained even at 2 years after surgery in 1 patient. In the radiological examination, the preoperative C2–7 lordosis angle in the fusion group was significantly less than the average value in the no-fusion group, while the average cervical lordosis was not different between the 2 groups after surgery (Table 1). The average ROM in the cervical spine decreased after surgery in both groups, although no significant difference was detected between the groups. In our analysis of factors influencing the postoperative occurrence of C-5 palsy, all 6 patients with C-5 palsy in the fusion group had undergone C4–5 spinal fusion (Table 2). In the fusion group, both local kyphosis and spondylolisthesis were significantly reduced after surgery (Table 3). In the fusion group, the width of the C4–5 intervertebral foramen in the C-5 palsy cases was significantly smaller on the paralyzed side than on the normal side or on the bilateral sides in the cases without C-5 palsy (Table 4). Logistic regression analysis for risk factors showed that cervical fusion was a predictive factor for C-5 palsy after the surgery (Table 5).
Discussion
Patients with cervical myelopathy who underwent laminoplasty with or without posterior instrumented spinal fusion were compared in the present study. There were no significant differences in surgical results, as the recovery rate of the JOA score demonstrated. However, more patients in the fusion group had significantly more severe C-5 palsy than those in the no-fusion group. Moreover, cervical fusion was a predictive factor for C-5 palsy according to TABLE 2: Fusion level and C-5 palsy
TABLE 3: Local kyphosis and spondylolisthesis after spinal fusion Disorder
Preop
Postop
local kyphosis (°) spondylolisthesis (mm)
2.7 ± 8.6 3 ± 1.3
−1.3 ± 6.4* 0.9 ± 1.3*
* p < 0.05.
logistic regression analysis. Thus, instrumented spinal fusion may be a risk factor for C-5 palsy. Several authors have hypothesized that complications involving the nerve roots may depend on tethering of the nerve roots and circulation around the cord after laminoplasty.3,15,18 In the present study, as demonstrated by the C2–7 angle, the overall cervical alignment had more kyphosis in the fusion group than in the no-fusion group preoperatively, and local kyphosis and spondylolisthesis were reduced after surgery in the fusion group. Moreover, all patients in the fusion group who had C-5 palsy underwent spinal fusion at C4–5. The width of the C4–5 foramen was significantly narrower on the paralyzed side than on the normal side or, in cases without palsy, on the bilateral sides. This relationship between preoperative foraminal stenosis and the occurrence of postoperative C-5 palsy corresponds to documented results in recent papers.8,9,13 Several authors have indicated that correction and fusion using instrumentation may cause iatrogenic intervertebral foraminal stenosis.1,7,17 Based on results in the present study, the presence of preoperative foraminal stenosis as well as correction of kyphosis or spondylolisthesis at C4–5 after spinal fusion may contribute to C-5 palsy. Sasai et al. reported that the incidence of C-5 palsy in patients undergoing laminoplasty and foraminotomy was significantly lower than in patients undergoing laminoplasty alone.15 Therefore, adequate correction of kyphosis combined with foraminotomy at C4–5 may prevent C-5 palsy if intervertebral foraminal stenosis is present. The change in ROM probably did not influence the incidence of C-5 palsy in the present study, because ROM decreased in both groups after surgery. Some authors have demonstrated that degeneration of the spinal cord is a risk factor for C-5 palsy;2,4 however, degeneration of the spinal cord was not a predictive factor for C-5 palsy in the present study. Limitations of the present study are as follows: the design was a retrospective case review, the number of included patients was small, and the follow-up period was short. Thus, the data were not robust enough to draw definite conclusions. TABLE 4: C-5 intervertebral foramen in the fusion group C-5 Palsy
Fusion Level
No. of C-5 Palsy Cases/Total
C-3, C-4 C-4, C-5 C-3, C-4, C-5 C-4, C-5, C-6 C-3, C-4, C-5, C-6
0/9 2/5 2/5 1/3 1/2
J Neurosurg: Spine / Volume 20 / January 2014
present side w/ palsy side w/o palsy absent bilat sides
Width of C4–5 Intervertebral Foramen 1.7 ± 0.7* 2.4 ± 1.1 2.8 ± 0.8
* p < 0.05.
3
K. Yamanaka et al. TABLE 5: Results of logistic regression analysis* Factor
p Value
age spinal fusion change in C2–7 angle change in ROM HIA in spinal cord
0.472 0.023† 0.563 0.782 0.999
OR (95% CI) 18.991 (1.50–239.909)
* HIA = high intensity area. † p < 0.05.
Conclusions
In summary, the incidence of postoperative C-5 palsy in patients undergoing laminoplasty and spinal reduction and fusion was significantly higher than in patients undergoing laminoplasty without spinal fusion. Posterior reduction and fusion with instrumentation and preoperative foraminal stenosis may be risk factors for C-5 palsy. Adequate correction of kyphosis or foraminotomy may prevent iatrogenic intervertebral foraminal stenosis and C-5 palsy. Acknowledgment We thank Mr. Devin Casadey for his help editing the manuscript. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation include the following. Conception and design: Yamanaka. Acquisition of data: Tachibana, Yamanaka. Analysis and interpretation of data: Tachibana, Yamanaka. Drafting the article: all authors. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Tachibana. Statistical analysis: Tachibana. Study supervision: Moriyama, Yoshiya. References 1. Abumi K, Shono Y, Ito M, Taneichi H, Kotani Y, Kaneda K: Complications of pedicle screw fixation in reconstructive surgery of the cervical spine. Spine (Phila Pa 1976) 25:962–969, 2000 2. Chiba K, Toyama Y, Matsumoto M, Maruiwa H, Watanabe M, Hirabayashi K: Segmental motor paralysis after expansive open-door laminoplasty. Spine (Phila Pa 1976) 27:2108–2115, 2002 3. Fan D, Schwartz DM, Vaccaro AR, Hilibrand AS, Albert TJ: Intraoperative neurophysiologic detection of iatrogenic C5 nerve root injury during laminectomy for cervical compression myelopathy. Spine (Phila Pa 1976) 27:2499–2502, 2002 4. Hashimoto M, Mochizuki M, Aiba A, Okawa A, Hayashi K, Sakuma T, et al: C5 palsy following anterior decompression and
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spinal fusion for cervical degenerative diseases. Eur Spine J 19:1702–1710, 2010 5. Hirabayashi K, Toyama Y, Chiba K: Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament. Clin Orthop Relat Res (359):35–48, 1999 6. Hirabayashi K, Watanabe K, Wakano K, Suzuki N, Satomi K, Ishii Y: Expansive open-door laminoplasty for cervical spinal stenotic myelopathy. Spine (Phila Pa 1976) 8:693–699, 1983 7. Heller JG, Silcox DH III, Sutterlin CE III: Complications of posterior cervical plating. Spine (Phila Pa 1976) 20:2442– 2448, 1995 8. Imagama S, Matsuyama Y, Yukawa Y, Kawakami N, Kamiya M, Kanemura T, et al: C5 palsy after cervical laminoplasty: a multicentre study. J Bone Joint Surg Br 92:393–400, 2010 9. Katsumi K, Yamazaki A, Watanabe K, Ohashi M, Shoji H: Can prophylactic bilateral C4/5 foraminotomy prevent postoperative C5 palsy after open-door laminoplasty? A prospective study. Spine (Phila Pa 1976) 37:748–754, 2012 10. Komagata M, Nishiyama M, Endo K, Ikegami H, Tanaka S, Imakiire A: Prophylaxis of C5 palsy after cervical expansive laminoplasty by bilateral partial foraminotomy. Spine J 4: 650–655, 2004 11. Maeda T, Arizono T, Saito T, Iwamoto Y: Cervical alignment, range of motion, and instability after cervical laminoplasty. Clin Orthop Relat Res (401):132–138, 2002 12. Minoda Y, Nakamura H, Konishi S, Nagayama R, Suzuki E, Yamano Y, et al: Palsy of the C5 nerve root after midsagittalsplitting laminoplasty of the cervical spine. Spine (Phila Pa 1976) 28:1123–1127, 2003 13. Nakashima H, Imagama S, Yukawa Y, Kanemura T, Kamiya M, Yanase M, et al: Multivariate analysis of C-5 palsy incidence after cervical posterior fusion with instrumentation. Clinical article. J Neurosurg Spine 17:103–110, 2012 14. Sakaura H, Hosono N, Mukai Y, Ishii T, Yoshikawa H: C5 palsy after decompression surgery for cervical myelopathy: review of the literature. Spine (Phila Pa 1976) 28:2447–2451, 2003 15. Sasai K, Saito T, Akagi S, Kato I, Ohnari H, Iida H: Preventing C5 palsy after laminoplasty. Spine (Phila Pa 1976) 28:1972– 1977, 2003 16. Suda K, Abumi K, Ito M, Shono Y, Kaneda K, Fujiya M: Local kyphosis reduces surgical outcomes of expansive opendoor laminoplasty for cervical spondylotic myelopathy. Spine (Phila Pa 1976) 28:1258–1262, 2003 17. Takemitsu M, Cheung KMC, Wong YW, Cheung WY, Luk KDK: C5 nerve root palsy after cervical laminoplasty and posterior fusion with instrumentation. J Spinal Disord Tech 21:267–272, 2008 18. Tsuzuki N, Abe R, Saiki K, Zhongshi L: Extradural tethering effect as one mechanism of radiculopathy complicating posterior decompression of the cervical spinal cord. Spine (Phila Pa 1976) 21:203–211, 1996 19. Uematsu Y, Tokuhashi Y, Matsuzaki H: Radiculopathy after laminoplasty of the cervical spine. Spine (Phila Pa 1976) 23: 2057–2062, 1998 Manuscript submitted October 12, 2012. Accepted September 19, 2013. Please include this information when citing this paper: published online October 25, 2013; DOI: 10.3171/2013.9.SPINE12952. Address correspondence to: Toshiya Tachibana, M.D., Ph.D., Department of Orthopaedic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan. email: [email protected].
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C-5 palsy after cervical laminoplasty with instrumented posterior fusion Clinical article Kazuhiro Yamanaka, M.D., Toshiya Tachibana, M.D., Ph.D., Tokuhide Moriyama, M.D., Ph.D., Fumiaki Okada, M.D., Ph.D., Keishi Maruo, M.D., Ph.D., Shinichi Inoue, M.D., Ph.D., Yutaka Horinouchi, M.D., and Shinichi Yoshiya, M.D., Ph.D. Department of Orthopaedic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan Object. Postoperative C-5 palsy is known as a common complication after cervical laminoplasty. The authors of this article have encountered postoperative C-5 palsy more often when laminoplasty was combined with instrumented posterior spinal fusion than when it was performed alone. The purpose of this clinical study was to examine the incidence of fifth cervical nerve root palsy (C-5 palsy) and surgical results in patients with cervical myelopathy who had undergone laminoplasty with or without instrumented spinal fusion. Methods. The authors retrospectively studied patients with cervical myelopathy who had undergone laminoplasty with or without instrumented posterior spinal fusion. Results. Clinical data on 58 patients were evaluated and analyzed. Preoperative diagnoses were cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament of the cervical spine. Twenty-four patients with spondylolisthesis or kyphosis underwent laminoplasty combined with posterior spinal fusion using instrumented lateral mass fixation (fusion group), while the remaining 34 patients underwent laminoplasty without posterior spinal fusion (no-fusion group). In the fusion group, C-5 palsy developed in 6 patients; in the no-fusion group, it occurred in only 1 patient. There was a significant difference in the rate of this complication between the 2 groups. In the fusion group, local kyphosis and spondylolisthesis level were reduced at the fusion level, and all patients with C-5 palsy underwent C4–5 spinal fusion. Conclusions. The incidence of postoperative C-5 palsy is significantly higher after laminoplasty when it is combined with spinal fusion. Correction of kyphosis and spondylolisthesis using posterior instrumentation may be a risk factor for iatrogenic intervertebral foraminal stenosis leading to C-5 palsy. (http://thejns.org/doi/abs/10.3171/2013.9.SPINE12952)
Key Words • C-5 palsy • laminoplasty • posterior fusion • cervical myelopathy
L
aminoplasty is a surgical option widely used for cervical myelopathy. Authors of a number of clinical studies have examined the results of this surgical procedure by analyzing the factors influencing outcome. Among the pinpointed factors is cervical kyphosis, which is related to a poor prognosis because the spinal cord is not well decompressed in the kyphotic spine.11,16 Cervical spondylolisthesis is regarded as another factor affecting outcome, accompanied by progressive instability of the cervical spine after surgery. Therefore, we have performed reduction and fusion with instrumentation
Abbreviations used in this paper: JOA = Japanese Orthopaedic Association; MMT = manual muscle test; ROM = range of motion.
J Neurosurg: Spine / Volume 20 / January 2014
concomitant with laminoplasty for cervical myelopathy patients presenting with cervical spondylolisthesis or cervical kyphosis. Among the complications following cervical laminoplasty is fifth cervical nerve root palsy, which has been reported as one of the most frequently encountered problems.2,3,8,10–12,14,15,18,19 In our experience, C-5 palsy occurs after laminoplasty more often when the procedure is combined with posterior spinal fusion. We hypothesized that concomitant reduction of kyphosis or spondylolisthesis and spinal fusion is a risk factor for C-5 palsy after cervical laminoplasty, and that there may be some issues associated with the occurrence of this complication. To test this hypothesis, we reviewed our experience with postoperative C-5 palsy in patients 1
K. Yamanaka et al. who had undergone laminoplasty with and without instrumented spinal fusion. Additionally, we analyzed the clinical features of patients with this complication to clarify the pathological mechanism.
Methods
The local ethics committee authorized this study. We collected from our departmental database all cases treated using laminoplasty with or without instrumented posterior cervical spine fusion in the period from 1998 to 2004. In the clinical evaluation, the incidence of C-5 palsy after surgery and the subsequent recovery process were reviewed on patient charts. Clinical scores were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy2 both pre- and postoperatively, and the postoperative recovery rate was calculated as follows: (postoperative JOA score - preoperative JOA score) × 100/(17 - preoperative JOA score).6 In the radiological examination, the postoperative change in cervical kyphosis/lordosis was assessed according to the difference in the C2–7 angle in the neutral position. Range of motion (ROM) of the cervical spine was calculated using the change in the C2–7 angle from maximum flexion to extension positions. In the fusion group, the fusion level as well as the postoperative change in local kyphosis and spondylolisthesis was assessed on radiographs. Thereafter, comparative analysis was performed between the groups using these parameters. Moreover, CT was used to measure the width of the intervertebral foramen at C4–5 in the fusion group. The CT images were acquired in the intervertebral disc. The width of the C4–5 foramen was measured at its narrowest point. In the analysis of potential factors influencing the occurrence of C-5 palsy, the prognostic predictive value was assessed using logistic regression analysis for the following parameters: postoperative change in the C2–7 angle in the neutral position, ROM in the cervical spine, and presence of high intensity areas in the cervical spinal cord on T2-weighted MR images. In the statistical analysis to detect differences between groups, the Student t-test was performed using Excel (Microsoft Corp.), whereas chi-square analysis, Fisher exact test, and logistic regression analysis were performed using SPSS software (SPSS Inc.). A p value < 0.05 was considered to indicate significance.
Results
Fifty-eight consecutive patients who had undergone laminoplasty with or without instrumented posterior spinal fusion in the period from 1998 to 2004 were included in this study. Bilateral midsagittal-splitting open-door laminoplasty with or without lamina spacers5,16 was performed as an isolated procedure in 34 patients (no-fusion group), whereas laminoplasty without lamina spacers was supplemented with instrumented posterior spinal fusion using lateral mass screws in the remaining 24 patients (fusion group). In the no-fusion group, 28 patients underwent laminoplasty without lamina spacers; the procedure was 2
switched to laminoplasty with the use of lamina spacers for 6 patients in the later study period. All patients in the fusion group received autogenous bone grafts using local bone. Regarding instrumentation in the fusion group, the Olerud rod system was used in 9 cases and the Axis plate system in 15 cases. No patient in either group underwent foraminotomy. Neither was electrophysiological monitoring performed in any of the patients. Preoperative diagnoses were cervical spondylotic myelopathy in 39 patients and cervical ossification of the posterior longitudinal ligament in 19. Concomitant posterior spinal fusion was performed when spondylolisthesis (more than 3 mm) or local kyphosis (more than 3°) was present. All patients were followed up for more than 1 year. There were no significant differences in the average age at surgery, average follow-up period, sex distribution, or diagnosis between the groups (Table 1). In the fusion group, the average JOA score before surgery was 8.6 ± 2.8. At the latest follow-up, the average score increased to 12.6 ± 3.1, and the recovery rate was 52.6%. In the no-fusion group, the average JOA score before surgery was 9.0 ± 2.4. The average score increased to 13.4 ± 2.0 at the latest follow-up, and the recovery rate was 56.5%. Although significant postoperative improveTABLE 1: Summary of data in 58 patients who underwent cervical laminoplasty* Parameter
Fusion
total no. of patients 24 mean age at surgery in yrs (range) 63.0 (36–81) M/F 15/9 mean FU in mos 49 no. of patients w/ CSM 14 no. of patients w/ OPLL 10 JOA score preop 8.6 ± 2.8 latest FU 12.6 ± 3.1 recovery rate 52.6% C-5 palsy yes 6† no 18 time to recover from C-5 palsy (no. of patients) wks 2 mos 3 patients w/ permanent palsy 1 change in overall alignment in cervical spine (º) preop 4.7 ± 10.6† postop 4.5 ± 10.5 change in ROM in cervical spine (º) preop 31.6 ± 12.5 postop 15.9 ± 11.6
No Fusion 34 62.7 (40–83) 23/11 39 25 9 9.0 ± 2.4 13.4 ± 2.0 56.5% 1† 33
1 0 0
17.3 ± 13.9† 10.5 ± 18.4 35.2 ± 12.0 9.2 ± 10.2
* CSM = cervical spondylotic myelopathy; FU = follow-up; OPLL = ossification of the posterior longitudinal ligament. † Significant difference between the groups (p < 0.05).
J Neurosurg: Spine / Volume 20 / January 2014
C-5 palsy after cervical laminoplasty with posterior fusion ment in the clinical score was detected in both groups, there was no significant difference in the score at the final follow-up between the groups (Table 1). Among the 24 patients in the fusion group, C-5 palsy developed in 6, while only 1 patient among the 34 in the no-fusion group had C-5 palsy, thus demonstrating a significant difference in the incidence between the groups (p < 0.05; Table 1). Of the 6 patients with C-5 palsy in the fusion group, 2 had OPLL and 4 had CSM, while 1 patient with C-5 palsy in the no-fusion group had OPLL. No significant relationship was demonstrated between preoperative diagnosis and the rate of C-5 palsy postoperatively. Muscle weakness according to the manual muscle test (MMT) was Grade 4 in 2 patients, Grade 3 in 3 patients, and Grade 2 in 2 patients. During the subsequent time course in the 7 patients with C-5 palsy, muscle strength was recovered to an MMT Grade 5 within a few weeks in 3 patients and in 3–6 months in 3 patients; the palsy remained even at 2 years after surgery in 1 patient. In the radiological examination, the preoperative C2–7 lordosis angle in the fusion group was significantly less than the average value in the no-fusion group, while the average cervical lordosis was not different between the 2 groups after surgery (Table 1). The average ROM in the cervical spine decreased after surgery in both groups, although no significant difference was detected between the groups. In our analysis of factors influencing the postoperative occurrence of C-5 palsy, all 6 patients with C-5 palsy in the fusion group had undergone C4–5 spinal fusion (Table 2). In the fusion group, both local kyphosis and spondylolisthesis were significantly reduced after surgery (Table 3). In the fusion group, the width of the C4–5 intervertebral foramen in the C-5 palsy cases was significantly smaller on the paralyzed side than on the normal side or on the bilateral sides in the cases without C-5 palsy (Table 4). Logistic regression analysis for risk factors showed that cervical fusion was a predictive factor for C-5 palsy after the surgery (Table 5).
Discussion
Patients with cervical myelopathy who underwent laminoplasty with or without posterior instrumented spinal fusion were compared in the present study. There were no significant differences in surgical results, as the recovery rate of the JOA score demonstrated. However, more patients in the fusion group had significantly more severe C-5 palsy than those in the no-fusion group. Moreover, cervical fusion was a predictive factor for C-5 palsy according to TABLE 2: Fusion level and C-5 palsy
TABLE 3: Local kyphosis and spondylolisthesis after spinal fusion Disorder
Preop
Postop
local kyphosis (°) spondylolisthesis (mm)
2.7 ± 8.6 3 ± 1.3
−1.3 ± 6.4* 0.9 ± 1.3*
* p < 0.05.
logistic regression analysis. Thus, instrumented spinal fusion may be a risk factor for C-5 palsy. Several authors have hypothesized that complications involving the nerve roots may depend on tethering of the nerve roots and circulation around the cord after laminoplasty.3,15,18 In the present study, as demonstrated by the C2–7 angle, the overall cervical alignment had more kyphosis in the fusion group than in the no-fusion group preoperatively, and local kyphosis and spondylolisthesis were reduced after surgery in the fusion group. Moreover, all patients in the fusion group who had C-5 palsy underwent spinal fusion at C4–5. The width of the C4–5 foramen was significantly narrower on the paralyzed side than on the normal side or, in cases without palsy, on the bilateral sides. This relationship between preoperative foraminal stenosis and the occurrence of postoperative C-5 palsy corresponds to documented results in recent papers.8,9,13 Several authors have indicated that correction and fusion using instrumentation may cause iatrogenic intervertebral foraminal stenosis.1,7,17 Based on results in the present study, the presence of preoperative foraminal stenosis as well as correction of kyphosis or spondylolisthesis at C4–5 after spinal fusion may contribute to C-5 palsy. Sasai et al. reported that the incidence of C-5 palsy in patients undergoing laminoplasty and foraminotomy was significantly lower than in patients undergoing laminoplasty alone.15 Therefore, adequate correction of kyphosis combined with foraminotomy at C4–5 may prevent C-5 palsy if intervertebral foraminal stenosis is present. The change in ROM probably did not influence the incidence of C-5 palsy in the present study, because ROM decreased in both groups after surgery. Some authors have demonstrated that degeneration of the spinal cord is a risk factor for C-5 palsy;2,4 however, degeneration of the spinal cord was not a predictive factor for C-5 palsy in the present study. Limitations of the present study are as follows: the design was a retrospective case review, the number of included patients was small, and the follow-up period was short. Thus, the data were not robust enough to draw definite conclusions. TABLE 4: C-5 intervertebral foramen in the fusion group C-5 Palsy
Fusion Level
No. of C-5 Palsy Cases/Total
C-3, C-4 C-4, C-5 C-3, C-4, C-5 C-4, C-5, C-6 C-3, C-4, C-5, C-6
0/9 2/5 2/5 1/3 1/2
J Neurosurg: Spine / Volume 20 / January 2014
present side w/ palsy side w/o palsy absent bilat sides
Width of C4–5 Intervertebral Foramen 1.7 ± 0.7* 2.4 ± 1.1 2.8 ± 0.8
* p < 0.05.
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K. Yamanaka et al. TABLE 5: Results of logistic regression analysis* Factor
p Value
age spinal fusion change in C2–7 angle change in ROM HIA in spinal cord
0.472 0.023† 0.563 0.782 0.999
OR (95% CI) 18.991 (1.50–239.909)
* HIA = high intensity area. † p < 0.05.
Conclusions
In summary, the incidence of postoperative C-5 palsy in patients undergoing laminoplasty and spinal reduction and fusion was significantly higher than in patients undergoing laminoplasty without spinal fusion. Posterior reduction and fusion with instrumentation and preoperative foraminal stenosis may be risk factors for C-5 palsy. Adequate correction of kyphosis or foraminotomy may prevent iatrogenic intervertebral foraminal stenosis and C-5 palsy. Acknowledgment We thank Mr. Devin Casadey for his help editing the manuscript. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation include the following. Conception and design: Yamanaka. Acquisition of data: Tachibana, Yamanaka. Analysis and interpretation of data: Tachibana, Yamanaka. Drafting the article: all authors. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Tachibana. Statistical analysis: Tachibana. Study supervision: Moriyama, Yoshiya. References 1. Abumi K, Shono Y, Ito M, Taneichi H, Kotani Y, Kaneda K: Complications of pedicle screw fixation in reconstructive surgery of the cervical spine. Spine (Phila Pa 1976) 25:962–969, 2000 2. Chiba K, Toyama Y, Matsumoto M, Maruiwa H, Watanabe M, Hirabayashi K: Segmental motor paralysis after expansive open-door laminoplasty. Spine (Phila Pa 1976) 27:2108–2115, 2002 3. Fan D, Schwartz DM, Vaccaro AR, Hilibrand AS, Albert TJ: Intraoperative neurophysiologic detection of iatrogenic C5 nerve root injury during laminectomy for cervical compression myelopathy. Spine (Phila Pa 1976) 27:2499–2502, 2002 4. Hashimoto M, Mochizuki M, Aiba A, Okawa A, Hayashi K, Sakuma T, et al: C5 palsy following anterior decompression and
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spinal fusion for cervical degenerative diseases. Eur Spine J 19:1702–1710, 2010 5. Hirabayashi K, Toyama Y, Chiba K: Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament. Clin Orthop Relat Res (359):35–48, 1999 6. Hirabayashi K, Watanabe K, Wakano K, Suzuki N, Satomi K, Ishii Y: Expansive open-door laminoplasty for cervical spinal stenotic myelopathy. Spine (Phila Pa 1976) 8:693–699, 1983 7. Heller JG, Silcox DH III, Sutterlin CE III: Complications of posterior cervical plating. Spine (Phila Pa 1976) 20:2442– 2448, 1995 8. Imagama S, Matsuyama Y, Yukawa Y, Kawakami N, Kamiya M, Kanemura T, et al: C5 palsy after cervical laminoplasty: a multicentre study. J Bone Joint Surg Br 92:393–400, 2010 9. Katsumi K, Yamazaki A, Watanabe K, Ohashi M, Shoji H: Can prophylactic bilateral C4/5 foraminotomy prevent postoperative C5 palsy after open-door laminoplasty? A prospective study. Spine (Phila Pa 1976) 37:748–754, 2012 10. Komagata M, Nishiyama M, Endo K, Ikegami H, Tanaka S, Imakiire A: Prophylaxis of C5 palsy after cervical expansive laminoplasty by bilateral partial foraminotomy. Spine J 4: 650–655, 2004 11. Maeda T, Arizono T, Saito T, Iwamoto Y: Cervical alignment, range of motion, and instability after cervical laminoplasty. Clin Orthop Relat Res (401):132–138, 2002 12. Minoda Y, Nakamura H, Konishi S, Nagayama R, Suzuki E, Yamano Y, et al: Palsy of the C5 nerve root after midsagittalsplitting laminoplasty of the cervical spine. Spine (Phila Pa 1976) 28:1123–1127, 2003 13. Nakashima H, Imagama S, Yukawa Y, Kanemura T, Kamiya M, Yanase M, et al: Multivariate analysis of C-5 palsy incidence after cervical posterior fusion with instrumentation. Clinical article. J Neurosurg Spine 17:103–110, 2012 14. Sakaura H, Hosono N, Mukai Y, Ishii T, Yoshikawa H: C5 palsy after decompression surgery for cervical myelopathy: review of the literature. Spine (Phila Pa 1976) 28:2447–2451, 2003 15. Sasai K, Saito T, Akagi S, Kato I, Ohnari H, Iida H: Preventing C5 palsy after laminoplasty. Spine (Phila Pa 1976) 28:1972– 1977, 2003 16. Suda K, Abumi K, Ito M, Shono Y, Kaneda K, Fujiya M: Local kyphosis reduces surgical outcomes of expansive opendoor laminoplasty for cervical spondylotic myelopathy. Spine (Phila Pa 1976) 28:1258–1262, 2003 17. Takemitsu M, Cheung KMC, Wong YW, Cheung WY, Luk KDK: C5 nerve root palsy after cervical laminoplasty and posterior fusion with instrumentation. J Spinal Disord Tech 21:267–272, 2008 18. Tsuzuki N, Abe R, Saiki K, Zhongshi L: Extradural tethering effect as one mechanism of radiculopathy complicating posterior decompression of the cervical spinal cord. Spine (Phila Pa 1976) 21:203–211, 1996 19. Uematsu Y, Tokuhashi Y, Matsuzaki H: Radiculopathy after laminoplasty of the cervical spine. Spine (Phila Pa 1976) 23: 2057–2062, 1998 Manuscript submitted October 12, 2012. Accepted September 19, 2013. Please include this information when citing this paper: published online October 25, 2013; DOI: 10.3171/2013.9.SPINE12952. Address correspondence to: Toshiya Tachibana, M.D., Ph.D., Department of Orthopaedic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan. email: [email protected].
J Neurosurg: Spine / Volume 20 / January 2014
