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ORIGINAL ARTICLE
Year : 2020  |  Volume : 33  |  Issue : 4  |  Page : 1393-1398

Comparative study of posterior cervical laminectomy vs facet fixation without laminectomy for the treatment of cervical spondylotic myelopathy


Department of Neurosurgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt

Date of Submission25-Mar-2020
Date of Decision28-Apr-2020
Date of Acceptance10-May-2020
Date of Web Publication24-Dec-2020

Correspondence Address:
Ahmed F Elmahdy
Department of Neurosurgery, Faculty of Medicine, Menoufia University, Menoufia
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mmj.mmj_86_20

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  Abstract 


Objective
The aim was to compare facet fixation operation as the sole management of cervical spondylotic myelopathy (CSM) vs posterior cervical laminectomy without facet fixation.
Background
CSM is a chronic spinal cord dysfunction in the cervical region due to cervical spondylosis, which is an age-related degenerative disorder of the cervical spine components. It is caused by a combination of static and dynamic degenerative factors in the adult population of more than 50 years. Surgical decompression of the spinal canal is the primary treatment of choice, which can be done directly by eliminating the static factors as in posterior cervical laminectomy or indirectly by eliminating the dynamic factors as in facet fixation leading to regression of the spondylotic process.
Patients and methods
This comparative prospective study involved 40 patients with CSM, who were randomly distributed into two equal groups. The patients were followed up for 6 months.
Results
Among the 40 patients, two groups were described. Group 1 included 20 patients who underwent posterior cervical laminectomy without fixation. Group 2 included 20 patients who underwent facet fixation without laminectomy. Postoperative neurological recovery rate at the end of the follow-up period was satisfactory (excellent and good) in 55% in group 1 and 70% in group 2.
Conclusion
Both facet fixation and posterior cervical laminectomy techniques are simple, safe, and effective procedures in achieving relief and improvement in patients with multilevel CSM. Facet fixation provided better postoperative Nurick's grades, Modified Japanese Orthopedic Association scores, and better postoperative neurological recovery rate (NRR) without significant complications while postoperative instability and kyphosis remains the main drawback of posterior cervical laminectomy.

Keywords: cervical fixation, facet, fusion, laminectomy, myelopathy, spondylosis


How to cite this article:
Elmahdy AF, Gaber EE, Hanafy A, Azab A, Gabry A, Elkholy H. Comparative study of posterior cervical laminectomy vs facet fixation without laminectomy for the treatment of cervical spondylotic myelopathy. Menoufia Med J 2020;33:1393-8

How to cite this URL:
Elmahdy AF, Gaber EE, Hanafy A, Azab A, Gabry A, Elkholy H. Comparative study of posterior cervical laminectomy vs facet fixation without laminectomy for the treatment of cervical spondylotic myelopathy. Menoufia Med J [serial online] 2020 [cited 2021 Apr 19];33:1393-8. Available from: http://www.mmj.eg.net/text.asp?2020/33/4/1393/304517




  Introduction Top


Cervical spondylotic myelopathy (CSM) is a spinal cord dysfunction in the neck due to degenerative factors with slow insidious onset presenting with variable symptoms and signs in the adult population[1]. The repeated injuries to the spinal cord, which result in CSM, are caused by both static and dynamic mechanical factors. A combination of these factors affects the spinal cord in two mechanisms: direct trauma and ischemia[2]. The primary treatment is the decompression of the spinal cord. Operations are performed to prevent advancement of clinical manifestations. The goal of the surgery is simply to prevent symptoms from getting any worse. The injury that has affected the cervical cord itself can regress and resolve, but it is difficult to expect the degree of reverse healing. The prognosis is different in every case[3]. The posterior surgical procedures including cervical laminectomy with or without fusion and cervical laminoplasty are performed for pathological compression that encompasses three or more vertebral body segments. The exactly selected maneuvers are determined according to the type of stenosis, the position of stenotic factors, the alignment of the cervical spine, and other factors[4]. Cervical laminectomy has been utilized for the treatment of multilevel cervical spondylosis. It provides adequate decompression of the cervical spinal cord and is easily performed. Potential risks include dural tear, bleeding, spinal cord injury, epidural scar formation, and instability, which result in postoperative pain, infection, and even neurological deterioration[5]. In 2010, Goel[6] presented a new surgical modality using the transarticular facet fixation and fusion operation without laminectomy as a simple, short, safe, and sufficient alternative surgery depending on his philosophy about the role of facet instability, hypermobility, and telescoping as the main factor of the vicious cycle of cervical spondylosis.

This study aimed to evaluate the results, complications, and the outcome of facet fixation operation without laminectomy in comparison with posterior cervical laminectomy without facet fixation, in the management of multilevel CSM.


  Patients and Methods Top


The current study is a comparative prospective study which involved 40 patients with CSM, who were admitted and managed in the Neurosurgical Department of Menoufia University from December 2017 to December 2019. Patients were randomly distributed into two equal groups by simple means of odd and even numbers technique. Group 1 included 20 patients who underwent posterior cervical laminectomy without fixation. Group 2 included 20 patients who underwent facet fixation without laminectomy. The patients were followed up for 6 months in the outpatient clinic of neurosurgery. Inclusion criteria involved patients with symptoms and signs of CSM with one or more of the following radiological criteria: Patients whose pathological compression encompasses three or more vertebral body segments and/or patients in whom thickened ligamentum flavum or hypertrophied facet joints compromise the posterior cervical canal. The exclusion criteria for selection of cases were: Patients whose pathologic compression encompasses less than three vertebral body segments and anterior to the spinal cord or patients with previous anterior or posterior cervical surgery, patients with cervical kyphosis of more than 5°, or patients with osteoporosis (T-score of bone mineral density at or below −2.5).

Approval for this study was obtained from Menoufia University Ethics Committee. Patients included in the study received information about the nature of the study and the possible benefits and complications of the treatment and signed an informed consent form.

All patients were subjected to history taking, full neurological examination, and classification by Nurick's functional grading[7] and the scale of the Modified Japanese Orthopedic Association (MJOA)[8].

For the posterior cervical laminectomy procedure, operations were done in the prone position. A high-speed drill was used to make a groove in the laminae bilaterally just before the facet joint. The laminae with the spinous process were removed as one piece[2]. For the facet fixation procedure, operations were done in the prone position with the chest elevated to between 15 and 30° with cervical traction, which was done before induction of anesthesia[6]. We used the Dal Canto technique[9], where the entrance point is 2 mm caudal to the midpoint of the lateral mass. Lateral angulation is 20° laterally. Sagittal inclination is 40° caudally. Klekamp technique was used if the facet gets cracked or loosened screws[10], where the entrance point is 1 mm medial and 1–2 mm caudal to the midpoint of the lateral mass. Lateral angulation is 20° laterally. Sagittal inclination is 40° caudally. A 2 mm high-speed drill was used to penetrate the bone at the entry point. Afterward, a 2.4 mm tap was used, and 2.7 mm diameter cortical screws were inserted. The usual length was between 12 and 14 mm. Bone grafts from dissected spinous processes and sometimes, iliac bone grafts were placed laterally on both sides of the decorticated facets and small bone chips are added to the facet interspace. Postoperatively, all patients were placed into a hard neck collar for 6–8 weeks.

Statistical analysis

Data analysis was performed using the Statistical Package for the Social Sciences for Windows version 20 (SPSS Inc., Chicago, Illinois, USA). Data were statistically described in terms of mean ± SD, range, frequencies (number of cases), and percentages when appropriate. Subgroups were compared by χ2-test, when appropriate. A two-sample t-test was used to test the mean differences between independent samples. Presurgical and postsurgical management were assessed using a paired t-test. The results were considered statistically significant at P values of less than 0.05.


  Results Top


The study included 40 patients. The mean age of group 1 and group 2 was 58.9 ± 7.3 years and 58.7 ± 6.5 years, respectively. Male sex was predominant (72.5% of cases), while women represented 27.5% of both groups. Male:female ratio was 2.64:1. The mean duration of symptoms was 12 ± 3.6 in group 1 and 7.5 ± 3.7 months in group 2 [Table 1]. The mean preoperative MJOA score was 8.2 ± 2.1 in group 1 and 9.3 ± 2.7 in group 2, while the mean postoperative MJOA scores score was 12.7 ± 2.8 in group 1 and 14.2 ± 1.9 in group 2 [Table 2]. The mean preoperative Nurick's functional grading was 4.2 ± 0.7 in group 1 and 3.95 ± 0.8 in group 2, while the mean postoperative Nurick's grading was 3 ± 1.1 in group 1 and 2.6 ± 0.7 in group 2 [Table 3]. According to the operative related complications in this study, there were no serious complications such as neurovascular injuries, CSF leak, or deep infection necessitating screw removal [Table 4]. The postoperative neurological recovery rate at the end of the follow-up period was satisfactory (excellent and good) in 55% in group 1 and 70% in group 2 [Table 5]. There were statistically significant differences regarding the postoperative clinical results in both groups. Group 2 had better 'improved' and less 'worsened' postoperative clinical results [Table 6]. In comparison between radiological data among the studied groups, there was no statistically significant difference regarding the preoperative radiological findings in both groups. In contrast, there was a statistically significant difference regarding postoperative radiological findings in both groups in this study [Table 7].
Table 1: Number, age, sex, and onset of presentation of patients of the study

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Table 2: Comparison of preoperative Modified Japanese Orthopedic Association score and postoperative score in the follow-up period at 6 months

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Table 3: Comparison of preoperative and postoperative Nurick's functional grades in both groups

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Table 4: Operative related complications in the studied groups

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Table 5: Neurological recovery rate at the end of follow-up period

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Table 6: Postoperative clinical results in both groups

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Table 7: Comparison of percentage of preoperative and postoperative radiological features of cervical spondylotic myelopathy at the end of follow-up period

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  Discussion Top


CSM is a condition of chronic spinal cord dysfunction in the cervical region with insidious onset and slowly progressive course as it is compromised by cervical spondylosis which is believed to be an age-related degenerative disorder of the cervical spine components with highly variable presenting symptoms and signs in the adult population over 50 years[4]. Brain et al .[11] defined it for the first time in 1952. CSM is caused by both dynamic and static factors. All efforts have been directed toward the elimination of the static factors like cervical intervertebral disks and disk-osteophyte complexes, hypertrophied ligaments, and/or ossified posterior longitudinal ligament[12],[13],[14]. Even the added fixation and eventually fusion is just complementary to the resection procedures to prevent the expected postoperative instability[1]. The oldest technique for posterior decompression of CSM is laminectomy without fusion. Nevertheless, the major postoperative complication of such an approach is post-laminectomy instability. The groups of patients at risk for such complication are those who present signs of preexisting instability and those in which aggressive facet resection is performed[2]. Goel directed his efforts to fix the dynamic factors only by a short, simple, safe, and sufficient procedure of only facet fixation proposing that facet instability is the main driving player of spondylotic process[6],[15]. Goel[6] realized that it is the instability not the compression or deformation, which is the main cause of the related microinjury to neural structures. Accordingly, he resorted to 'only facet fixation' of the involved spinal segments using the transarticular technique of fixation. No direct decompression of the bone or soft tissue and no resection of osteophyte or disk material were done. The remarkable clinical results give credence to the concept. He has treated cases with lumbar canal 'stenosis' with the same concept of only fixation without any decompression. Regression of all secondary features identified with CSM following a single act of facet fixation gives credence to this hypothesis. Other authors have validated this concept[1].

Remarkably gratifying clinical and radiological outcome was reported following only facet fixation of cervical segments by the transarticular technique of fixation without any anterior or posterior direct decompression. The observations on the basis of his increasing experience are that multilevel spinal fixation can revolutionize the treatment for cervical myelopathy related to ossification of the posterior longitudinal ligament[16]. This was a comparative prospective study that involved 40 patients with CSM, who were admitted and managed in the Neurosurgery Department of Menoufia University from December 2017 to December 2019. The patients were randomly distributed into two equal groups by simple means of odd and even numbers technique. Group 1 included 20 patients who underwent posterior cervical laminectomy without fixation. Group 2 included 20 patients who underwent facet fixation without laminectomy. The patients were followed up for 6 months in the outpatient clinic of neurosurgery. There was no significant association between age, sex, or duration of symptoms and NRR in both groups. Many studies in the literature concluded similar results in their studies that age, sex, or duration of symptoms of the patients at presentation was not important variables or prognostic factors influencing the surgical outcome[16],[17],[18],[19],[20],[21],[22]. Ryken et al . referenced clinical improvement after cervical laminectomy ranges from 42 to 90% and furthermore referenced the length of side effects was distinguished as an inclining variable since patients with asymptomatic period of more than a year arrived at lower long-term mean score value esteems. In any case, there is no noteworthy distinction in the practical status variety and medical procedure empowers a utilitarian improvement concerning myelopathy paying little mind to illness movement time[21]. Also, there was no statistically significant difference regarding the preoperative radiological findings in both groups, which agreed with other studies among patients with CSM in the literature[23]. In contrast, there was a statistically significant difference regarding the postoperative radiological findings in both groups in the current study. In group 1, loss of cervical lordosis incidence, changed from 50 to 70% of patients postoperatively[22]. Instability involved two more patients in addition to preoperative five patients[24]. The most depicted disadvantage in regard to cervical decompression by laminectomy includes the enlistment of kyphotic changes in the postoperative cervical sagittal alignment with expanded danger of long haul unsteadiness; in this manner, a few creators prescribed complimentary fusion maneuvers as a preventive system altogether improving the expanse of the strategy, usable time, blood loss, and includes explicit hazards for complications[5],[21],[22]. Kaptain et al .[22] covered 46 patients experiencing laminectomy who had preusable and postusable radiographic and presumed that the advancement of a postoperative distortion (kyphosis) was more than twice as likely in patients with a 'straight' preoperative spine (loss of lordosis) than in those with typical lordosis. In group 2, there was a significant reversal of loss of lordosis. No patients had instability. These results were close to Goel et al .[16],[25], regarding this technique. Goel and colleagues published that postoperative imaging showed restoration of the cervical alignment and distraction–fixation arthrodesis of the spinal segment. Ajiboye and colleagues concluded that patients with CSM who underwent posterior surgical fusion were associated with a regression in disk-osteophyte complex size compared with nonfusion posterior procedures. This was related to the loss of mobility of the cervical spine after the operation as governed by the Heuter-Volkmann's principle and Wolff's law[26]. Besides, Adedayo[27] reported regression of anterior disk-osteophyte complexes after posterior cervical fusion, complementary to laminectomy for CSM in a group of 24 patients who showed variable degrees of disk-osteophyte reversal and resorption with average 40% reduction in size by 3 and 6 months MRI of the cervical spine. The findings of this study suggest that regression of the anterior-disk-osteophyte complex also occurs following laminectomy and fusion, and likely provides another mechanism of the spinal cord decompression. There were no serious complications such as neurovascular injuries, CSF leak, or deep infections in both groups. In group 1, the postoperative C5 radicular pain and superficial wound infections match with Geest et al .[28], who identified a rate of 9% comprising postoperative C5 radiculopathy and superficial wound infection. Postoperative instability and kyphosis match with the reported results of Lad et al .[29] and Kaptain et al .[22] who reported that postoperative instability and kyphosis might occur in up to 21% of patients who have undergone laminectomy for CSM. In group 2, five (25%) patients had cracked facets in a single level at one side and the screws were reinserted by the Klekamp technique in the noncracked part. No screws pull up or break. No serious complications were recorded in the results of Goel[15], Goel et al .[16], Goel et al .[19], and Goel et al .[30]. There were statistically significant differences regarding the postoperative clinical results in both groups. Group 2 had better 'improved' and less 'worsened' postoperative clinical results. Postoperative neurological recovery rate at the end of the follow-up period was satisfactory in 55 and 70% in both groups, respectively. These results are close to the results of Ryken et al .[21], Goel et al .[16], and Goel et al .[25]. Both excellent and good recovery rates are considered satisfactory while fair or poor recovery rates are considered unsatisfactory.


  Conclusion Top


Both facet fixation and posterior cervical laminectomy techniques are simple, safe, and effective procedures in achieving relief and improvement in patients with multilevel CSM. Facet fixation provided better postoperative Nurick's grades, MJOA scores, and better postoperative NRR without significant complications, while postoperative instability and kyphosis remain the main drawback of posterior cervical laminectomy. Age, sex, duration of symptoms, preoperative clinical presentations, preoperative Nurick's grades, MJOA score, or preoperative radiological findings were not prognostic factors to the outcome of the two groups. Postoperative radiological findings in facet fixation and fusion concluded that regression and remodeling of the cervical spondylotic features provided indirect mechanism of spinal cord decompression.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]



 

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