Between July 2016 and January 2020, 70 consecutive patients underwent cervical internal fixation and decompression of traumatic cervical instability via the posterior approach performed at our institution by an experienced orthopedic surgeon (G.Y.L). Eleven of 70 patients underwent combined open-door laminoplasty with bilateral lateral mass screw fixation for multilevel cervical stenosis with traumatic cervical instability and were included in the present study. Patients treated via the combined anterior approach and those who did not undergo open-door laminoplasty were excluded.
The study protocol was approved by the Ethical Review Board of Ningbo No. 6 Hospital (approval no. L2022068). After reviewing the medical records and radiographs in our electronic medical record and imaging databases, we invited all patients who met the study inclusion and exclusion criteria to return to our hospital for follow-up clinical and radiographic evaluation. No patients were lost to follow-up.
All patients underwent routine computed tomography (CT) and magnetic resonance imaging (MRI) before surgery. CT was performed to identify small fractures. MRI was used to diagnose multilevel spinal cord compression and showed that no patient in the present cohort had posterior disc herniation compressing the anterior spinal cord. Dynamic plain radiography was not used to confirm segmental instability because all patients had traumatic injuries of the cervical ligaments or cervical vertebral fractures. Specific information for each patient is shown in Table 1.
Table 1
Presentation of the reviewed patients from this series.
Patient No. | Age | Gender | Diagnosis | Laminoplasty level | Screw fixation level | Nurick score before surgery | JOA scores before surgery | Follow-up (months) | Nurick score during follow-up | JOA score during follow-up |
1 | 67 | Male | Multi-level cervical canal stenosis Kyphotic deformity Cervical cord injury | C2-6 | C3-7 | 2 | 6 | 24 | 1 | 16 |
2 | 55 | Male | Multi-level cervical canal stenosis C5/6 facet fracture ALL injury Cervical cord injury | C3-7 | C3-7 | 5 | 5 | 30 | 1 | 15 |
3 | 70 | Male | Multi-level cervical canal stenosis C4-7 fractures Cervical cord injury | C3-7 | C4-T2 | 5 | 3 | 26 | 1 | 13 |
4 | 68 | Male | Multi-level cervical canal stenosis C5/6 fracture and dislocation Cervical cord injury | C3-7 | C3-T1 | 5 | 0 | 28 | 5 | 0 |
5 | 58 | Male | Multi-level cervical canal stenosis OPLL ALL injury Cervical cord injury | C3-6 | C2-6 | 2 | 5 | 25 | 1 | 14 |
6 | 67 | Male | Multi-level cervical canal stenosis C5 fracture Cervical cord injury | C3-7 | C4-6 | 3 | 11 | 26 | 2 | 14 |
7 | 50 | Male | Multi-level cervical canal stenosis ALL injury Cervical cord injury | C3-7 | C4-6 | 2 | 5 | 27 | 1 | 15 |
8 | 51 | Female | Multi-level cervical canal stenosis ALL injury Cervical cord injury | C3-7 | C4-5 | 3 | 6 | 24 | 1 | 14 |
9 | 65 | Male | Multi-level cervical canal stenosis Spondylolisthesis C4-5 ALL injury Cervical cord injury | C3-6 | C5-6 | 2 | 6 | 26 | 1 | 12 |
10 | 58 | Male | Multi-level cervical canal stenosis C5 tear-drop fracture Cervical cord injury | C3-7 | C4-6 | 2 | 5 | 30 | 1 | 11 |
11 | 69 | Female | Multi-level cervical canal stenosis Spondylolisthesis C4-5 ALL injury Cervical cord injury | C3-7 | C3-6 | 5 | 3 | 26 | 1 | 14 |
Mean | 59.8 | - | - | 4.9 | 4 | 3.2 | 5 | 26.5 | 1.4 | 12.5 |
Operative Technique
The operative details varied depending on the surgical indication, need for decompression and fixation, and number of levels to be included in the spinal construct. Somatosensory-evoked potentials were monitored during surgery to record basic data and detect any iatrogenic spinal cord injury. All patients were placed in the prone position with their head and cervical spine maintained in neutral position using a Mayfield head holder. For patients with unstable cervical spine fractures, Gardner-Wells skull traction tongs were used to reduce the fracture and maintain the alignment of the cervical spine. The spinous processes, laminae, and lateral masses of the posterior cervical spine were exposed in the usual manner.
Posterior open-door laminoplasty was performed using the Hirabayashi technique with titanium miniplates [7]. The side with the most severe symptoms was used as the open side. A high-speed drill was used to create bilateral channels. Before opening the laminae, screws were placed bilaterally and a rod was inserted on the hinged side. Fixation constructs that included C2, C7, T1, and T2 were stabilized with pedicle screws using a previously described technique [8, 9]. For fixation constructs that included the C3–C6 levels, lateral mass screws were placed bilaterally using the technique described by Magerl et al. [10]. The laminae were then opened and fixed in elevated positions using titanium miniplates. Another rod was inserted and fixed on the open side. Finally, the articular cartilage of the facet joints at the screw fixation levels was decorticated using a high-speed drill. Bone chips obtained from the spinous processes or laminae were placed within the joint interfaces.
Postoperative Management And Evaluation
All patients were immobilized with a rigid cervical collar for 12 weeks postoperatively. The postoperative evaluation, including the clinical examination and radiographic evaluation, was performed by an independent observer. Radiographs and CT images were obtained in the immediate postoperative period to confirm the optimal positioning of all instrumentation. At 3–5 months postoperatively, follow-up anteroposterior and lateral radiographs of the cervical spine were obtained to assess the fracture union and instrumentation problems. Fusion was evaluated on dynamic radiographs. If the fusion could not be adequately assessed on radiographs, reconstructed CT images were obtained. When necessary, postoperative MRI was performed to verify the enlargement of the spinal canal and decompression of the spinal cord.
The overall neurological functional result was evaluated using the pre- and postoperative Japanese Orthopaedic Association (JOA) scores and Nurick scores [11]. The JOA recovery rate was calculated from the JOA score data [11].
Data analyses were performed with SPSS 18.0 (SPSS Inc., Chicago, IL). Data are presented as the mean ± standard deviation for continuous variables. The unpaired Student t-test was performed to compare the pre- and postoperative JOA and Nurick scores. All p values were two-sided and values less than 0.05 were considered statistically significant.