Effects of two posterior procedures for treatment of cervical hyperextension injury with multilevel spinal stenosis: A retrospective study

doi:10.21203/rs.3.rs-4620932/v1

Download PDF

Research Article

Effects of two posterior procedures for treatment of cervical hyperextension injury with multilevel spinal stenosis: A retrospective study

https://doi.org/10.21203/rs.3.rs-4620932/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

Background

Cervical hyperextension injuries (CHI), commonly resulting in central cord syndrome and spinal instability, often affect the elderly with preexisting degenerative spinal changes, leading to a need for surgical interventions that address both the compression and stability of the cervical spine. This study compares the clinical outcomes of two posterior decompression and fixation procedures for treating cervical hyperextension injury in patients with preexisting multilevel spinal canal stenosis.

Methods

Patients suffering from cervical hyperextension injury combined with multilevel spinal stenosis were divided into two groups. They received laminoplasty combined with selective unilateral pedicle screw fixation or laminectomy combined with bilateral lateral mass screw fixation. The clinical records including demographic data, operation time, length of hospital stay, estimated blood loss and surgical complications were collected, and clinical outcomes were evaluated using the American Spinal Injury Association (ASIA) impairment scale. Preoperative and postoperative cervical lordosis were measured.

Results

Postoperative AISA scores were significantly increased compared with that before surgery in both groups, there was no significant differences between groups. The intraoperative blood loss in the laminoplasty group was significantly less than that in the laminectomy group and there were no significant differences in operation time and length of hospital stay between the two groups. No significant difference was found in the incidence of overall surgical complications between the two groups. There was no significant difference in the cervical lordosis after surgery compared with that before surgery in both groups.

Conclusions

For patients suffering from cervical hyperextension injury combined with preexisting multilevel spinal stenosis, both cervical laminoplasty with selective unilateral pedicle screw fixation and laminectomy with bilateral lateral mass screw fixation could achieve satisfactory clinical outcomes.

Cervical hyperextension injury

Cervical spinal stenosis

Laminoplasty

Laminectomy

Posterior fixation and fusion

Cervical hyperextension injury (CHI) is a clinically common type of cervical spine trauma and often results in occurrence of central cord syndrome. It can lead to rupture of the discoligamentous complex and consequent instability of the cervical spine even in the absence of vertebral fractures or dislocations (1). It often occurs in the elderly, who may have preexisting degenerative changes in the cervical spine, such as intervertebral disc protrusion, vertebral osteophytes, thickening and folding of the ligamentum flavum, and ossification of the posterior longitudinal ligament. These degenerative changes could cause cervical spinal canal stenosis and compression of the spinal cord. On this basis, the hyperextension force exerted on the cervical spine might lead to acute cervical spinal cord injury. The spinal cord suffers not only the preexisting static compression but also dynamic compression caused by the segmental instability (2, 3).

Surgical treatment is more advantageous for the recovery of spinal cord function compared to conservative treatment (4). It is crucial to relieve the spinal cord compression and reconstruct stability of the injured segments (5). If the spinal cord compression primarily arises from the anterior intervertebral discs and osteophytes without multilevel spinal canal stenosis, an anterior approach can simultaneously provide direct decompression and stability of the injured segments. When the patients with preexisting multilevel spinal canal stenosis suffer from hyperextension injuries, posterior procedures such as laminoplasty or laminectomy can contribute to extensive and thorough decompression of the spinal canal with a combined posterior fixation providing segmental stability. The effects of both posterior procedures have been confirmed. However, to our knowledge, there is a limited amount of literature comparing the efficacy of the two approaches for patients suffering from CHI combined with preexisting multilevel cervical stenosis. Therefore, we performed a retrospective study to compare the clinical outcomes of the two procedures.

Patient population

This retrospective study included 56 patients in our institution between January 2016 and December 2020. Inclusion criteria including (1) patients presented with upper limb hyperalgesia, hypoesthesia and/or decreased muscle strength following a cervical injury with hyperextension mechanism; (2) MRI showing the discoligamentous complex injury and multilevel spinal canal stenosis; (3) receiving posterior cervical spine surgery. Exclusion criteria consisted of (1) patients underwent anterior and posterior surgical procedures; (2) presence of upper cervical spine deformities; (3) spinal canal stenosis extending into the thoracic spine, with decompression extending beyond the cervical spine. The institutional review board approved this study and waived the requirement for informed consent due to the retrospective nature of this study.

Surgical procedures

Based on the different surgical approaches, the cases were divided into two groups: the laminoplasty group (laminoplasty with selective unilateral pedicle screw fixation) and laminectomy group (laminectomy with bilateral lateral mass screw fixation). In the laminoplasty group, patients underwent C3-6 unilateral open-door laminoplasty from the side with more severe neurological deficits. A mini titanium plate was used to maintain the position of the laminar on the open side. Unilateral pedicle screw fixation was performed in the segments of discoligamentous complex injury, typically on the hinge gutter side, preserving the facet joint capsule intact in the unfixed levels (Fig. 1). In the laminectomy group, patients underwent C3-6 total laminectomy, followed by bilateral lateral mass screw fixation from C3 to C6 (Fig. 2). Partial hemilaminectomy was performed at the upper edge of the C7 lamina when involving C6/7 level. A dome-shaped laminoplasty was performed for C2 decompression when spinal canal stenosis involving C2/3 level. Autologous bone graft was performed for fusion within the fixed segments in both groups. A cervical collar was utilized for 3 to 4 weeks after surgery.

Clinical and radiological outcomes

The collected data included surgical duration, length of hospital stay, estimated blood loss, and surgical complications. Neurological function was evaluated by the ASIA impairment scale, and sensory and motor scores were recorded during the preoperative and the last follow-up evaluations. Preoperative radiographs included cervical spine anteroposterior and lateral X-rays, CT scan, and MRI. Patients received cervical spine anteroposterior and lateral X-rays at each follow-up. All radiographic parameters were measured using software tools built into a picture archiving and communication system. Cervical lordosis was measured between the inferior endplate of C2 and C7. Loss of lordosis was defined as a decrease of more than 5° in the postoperative cervical lordosis compared to the preoperative angle at final follow-up.

Statistical Analysis

The data were presented as mean ± standard deviation. Preoperative quantitative data between the two groups were compared using unpaired t-test or Mann-Whitney U test. Repeated measures analysis of variance was used to compare preoperative and postoperative variables within groups. Analysis of covariance was utilized for postoperative quantitative data after adjusting for the baseline value. The Chi-square test was used for categorical data comparisons between the two groups. Statistical analysis was performed using SPSS v22.0 (SPSS Inc., Chicago, IL) and a p-value less than 0.05 was considered statistically significant.

A total of 56 patients was enrolled in this study with 28 patients in each group. There were no significant differences in age, gender, and body mass index (BMI) between the two groups (Table 1). The postoperative sensory and motor scores were significantly improved in both groups. There was no significant difference in the scores between the two groups. The estimated blood loss in the laminoplasty group was significantly less than that in the laminectomy group. There were no significant differences in surgical duration and length of hospital stay between the two groups. Postoperative complications included C5 palsy, screw malposition, poor wound healing, incision infection, loss of lordosis, and adjacent segment degeneration. No severe complication occurred and the overall incidence of complications did not significantly differ between the two groups. No significant change in cervical lordosis between the postoperative and preoperative angle in both groups and there was no significant difference in cervical lordosis between the two groups (Table 2).

Table 1

Comparison of demographic data between the two groups
	Laminoplasty Group	Laminectomy Group	p value
n	28	28
Age (years)	62.5 ± 8.2	60.9 ± 8.1	0.464
Gender (Male/Female)	19/9	23/5	0.217
Body Mass Index (kg/m²)	23.6 ± 2.9	23.7 ± 2.5	0.399

Table 2

Comparison of clinical and radiographic outcomes between the two groups
	Laminoplasty Group	Laminectomy Group	p value
Follow-up time (months)	18.7 ± 4.8	19.9 ± 5.4	0.399
ASIA sensory score
Preoperative	105.7 ± 35.2	94.8 ± 36.3	0.266
Follow-up	140.1 ± 37.5*	136.8 ± 44.1*	0.767
ASIA motor score
Preoperative	54.1 ± 22.7	50.3 ± 24.4	0.556
Follow-up	74.6 ± 13.9*	67.3 ± 19.4*	0.114
Surgical duration (minutes)	145.2 ± 24.0	141.8 ± 27.8	0.631
Estimated blood loss (ml)	289.5 ± 63.6	329.8 ± 58.1	0.018*
Length of hospital stay (days)	8.6 ± 2.0	8.3 ± 2.1	0.609
Complications (n)	4	5	0.757
C5 palsy	0	1
Internal fixation malposition	1	0
Surgical site infection	0	1
Delayed wound healing	1	1
Loss of lordosis	2	0
Adjacent segment degeneration	0	2
Cervical Lordosis (°)
Preoperative	6.7 ± 10.7	6.1 ± 8.9	0.838
Follow-up	8.3 ± 9.5	9.8 ± 6.3	0.485
* p < 0.05 (Compared with preoperative data)
ASIA: American spinal injury association

Patients with preexisting degenerative canal stenosis are more prone to spinal cord injury when encountering cervical hyperextension force. Degenerative changes in the cervical spine lead to a reduction in the volume of the spinal canal. The decrease in buffer space for the spinal cord makes it more susceptible to compression and impact under the hyperextension force. Miyanji et al. analyzed a group of patients with cervical trauma and found that older patients with cervical degeneration experienced more severe spinal cord compression and injury (6). Uribe et al. found that cervical hyperextension could lead to folding of the degenerative ligamentum flavum, causing a shearing-type injury to the spinal cord (7). Besides, cervical extension could affect the volume of the spinal canal. The spinal cord occupies only 40% of the anterior-posterior diameter of the cervical canal in the mid-sagittal plane for healthy adults. During cervical extension, the anterior-posterior diameter of the cervical canal would decrease by approximate 2 to 3 mm (8). Therefore, excessive cervical extension could aggravate preexisting canal stenosis and compression of the spinal cord. Furthermore, the spinal degeneration reduces range of motion of the cervical spine. When undergoing excessive cervical extension, the discoligamentous complex rupture could disrupt the stability of the cervical spine. The hyperextension mechanism results in retrodisplacement of the intervertebral disc and adjacent vertebrae and consequent impingement of the spinal cord. Meanwhile, deformation of the spinal cord makes it more susceptible to injury from compressive forces in the anterior-posterior direction (9).

When patients exhibit neurological deficits, surgical treatment is necessary to achieve neurological decompression and segmental stability. All patients in this study had multilevel cervical stenosis, so posterior procedures were chosen to acquire adequate decompression of the spinal canal. Cervical laminoplasty and laminectomy have been proven to be equally effective in neurological decompression (10). Similarly, our results demonstrated significant improvement in spinal cord function in both groups and no significant difference in the degrees of improvement. Considering the difficulty in complete healing of the ruptured discoligamentous complex and potentially secondary instability, a supplementary fixation and fusion would be beneficial in the injured segments (11). Cervical laminectomy is an effective approach for the treatment of multilevel spinal stenosis. In this study, bilateral lateral mass screws were utilized following laminectomy. For the patients with combined CHI and stenosis, this approach can simultaneously relieve static compression by extensive laminectomy and eliminate dynamic instability by fixation and fusion.

Cervical laminoplasty is also commonly used to treat multilevel spinal stenosis. In addition, it was used for the treatment of cervical injury without obvious segmental instability. For example, laminoplasty could help patients with ossification of the posterior longitudinal ligament achieve satisfactory recovery after acute cervical injury (12). Conventionally, cervical laminoplasty is not suitable for cases with segmental instability due to potential risk of instability exacerbation. For those with segmental instability, the supplementary fixation should be used to restore stability (13). Chen et al. analyzed 15 cases treated by laminoplasty with lateral mass screw fixation due to ossification of the posterior longitudinal ligament combined with instability. They found that compared to laminectomy with fusion, this procedure had comparable clinical efficacy and a lower incidence of complications (14). Our results did not show significant difference in the complication rate between the two groups, which might be attributed to relatively small sample size and short-time follow-up. Even so, this procedure has some potential advantages. The retained lamina increases the fusion contact area and serves as a bony protective layer to reduce the risks for postoperative dural sac compression by hematoma or cicatrization and long-term dural adhesions (15). Additionally, it prevents excessive posterior drift of the dural sac, thus decreasing traction force on the nerve roots (16).

In this study, the selective unilateral pedicle screw fixation was chosen for the laminoplasty procedure based on the following reasons. First, placement of the pedicle screws does not interfere with opening of the lamina and placement of the mini-plate, while the lateral mass screws might hinder placement of the mini-plate on the lateral mass. Second, the instability induced by CHI is primarily in the flexion-extension direction, while motion of rotation and lateral bending is usually less affected. Despite weakness in resisting rotation and lateral bending, unilateral fixation can provide equivalent stability in the flexion-extension direction compared to bilateral fixation. A biomechanical study found that laminoplasty with unilateral lateral mass screw fixation is comparable to laminectomy with bilateral fixation in the flexion-extension stability (17). The strength of pedicle screw fixation is superior to lateral mass screw. Therefore, unilateral pedicle screw fixation is sufficient enough for the injured segments. Lastly, the selective fixation could lower possibility of adjacent segment degeneration by preserving most segmental motion (18).

This study has some limitations. First, there are differences between the two groups in decompression, fixation, and fixed segments. Therefore, we cannot determine the effect of each specific step on the clinical efficacy. However, this study compared laminoplasty with pedicle screw fixation and laminectomy with lateral mass screw fixation as two integrated surgical approaches. The results only indicate the efficacy of the combined strategies and are not applicable to the specific step. Second, both CHI and spinal stenosis could lead to neurological deficits. Since it was impossible to accurately evaluate the neurological function before the injury, it was unclear whether the neurological function at baseline was comparable between the two groups. Nevertheless, the improvement of the neurological function from the preoperative to postoperative assessment could elucidate the therapeutic effects of the two approaches. Finally, due to the lack of postoperative MRI at follow-up, the direct effect of decompression cannot be assessed. These issues may warrant further investigation.

For patients suffering from CHI combined with preexisting multilevel spinal canal stenosis, both cervical laminoplasty with selective unilateral pedicle screw fixation and laminectomy with bilateral lateral mass screw fixation could achieve satisfactory clinical outcomes.

Cervical hyperextension injuries (CHI); American Spinal Injury Association (ASIA); body mass index (BMI)

Ethics approval and consent to participate

The Shanghai Jiao Tong University School of Medicine affiliated Ninth People’s Hospital institutional review board approved this study and waived the requirement for informed consent due to the retrospective nature of this study.

Consent for publication

Not applicable.

Availability of data and materials

The datasets used and analysed during the current study are available from the corresponding author on reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

This study was supported by the grant of The National Natural Science Foundation of China (81972136, 82130073) and Shanghai Municipal Health Commission（202040329）Fengcheng Hospital of Fengxian District, Shanghai.

Authors' contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by YX and CZ. The first draft of the manuscript was written by ZL and TG and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Acknowledgements

Not applicable.

Aarabi B, Koltz M, Ibrahimi D. Hyperextension cervical spine injuries and traumatic central cord syndrome. Neurosurg Focus. 2008;25(5):E9.
Wang JJ, Xu ML, Zeng HZ, Zheng LD, Zhu SJ, Jin C, et al. The biomechanical effect of preexisting different types of disc herniation in cervical hyperextension injury. J Orthop Surg Res. 2021;16(1):527.
Thompson C, Gonsalves JF, Welsh D. Hyperextension injury of the cervical spine with central cord syndrome. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2015;24(1):195-202.
Lee S, Kim C, Ha JK, Jung SK, Park JH. Comparison of Early Surgical Treatment With Conservative Treatment of Incomplete Cervical Spinal Cord Injury Without Major Fracture or Dislocation in Patients With Pre-existing Cervical Spinal Stenosis. Clin Spine Surg. 2021;34(3):E141-e6.
Chen L, Yang H, Yang T, Xu Y, Bao Z, Tang T. Effectiveness of surgical treatment for traumatic central cord syndrome. J Neurosurg Spine. 2009;10(1):3-8.
Miyanji F, Furlan JC, Aarabi B, Arnold PM, Fehlings MG. Acute cervical traumatic spinal cord injury: MR imaging findings correlated with neurologic outcome--prospective study with 100 consecutive patients. Radiology. 2007;243(3):820-7.
Uribe J, Green BA, Vanni S, Moza K, Guest JD, Levi AD. Acute traumatic central cord syndrome--experience using surgical decompression with open-door expansile cervical laminoplasty. Surg Neurol. 2005;63(6):505-10; discussion 10.
Devereaux MW. Anatomy and examination of the spine. Neurol Clin. 2007;25(2):331-51.
Saari A, Itshayek E, Cripton PA. Cervical spinal cord deformation during simulated head-first impact injuries. J Biomech. 2011;44(14):2565-71.
Bakr O, Soufi K, Jones Q, Bautista B, Van B, Booze Z, et al. Laminoplasty versus laminectomy with fusion for treating multilevel degenerative cervical myelopathy. N Am Spine Soc J. 2023;15:100232.
Yagi M, Ninomiya K, Kihara M, Horiuchi Y. Long-term surgical outcome and risk factors in patients with cervical myelopathy and a change in signal intensity of intramedullary spinal cord on Magnetic Resonance imaging. J Neurosurg Spine. 2010;12(1):59-65.
Gu Y, Chen L, Dong RB, Feng Y, Yang HL, Tang TS. Laminoplasty versus conservative treatment for acute cervical spinal cord injury caused by ossification of the posterior longitudinal ligament after minor trauma. Spine J. 2014;14(2):344-52.
Bridges KJ, Simpson LN, Bullis CL, Rekito A, Sayama CM, Than KD. Combined Laminoplasty and Posterior Fusion for Cervical Spondylotic Myelopathy Treatment: A Literature Review. Asian Spine J. 2018;12(3):446-58.
Chen Y, Wang X, Chen D, Miao J, Liao X, Yu F. Posterior hybrid technique for ossification of the posterior longitudinal ligament associated with segmental instability in the cervical spine. J Spinal Disord Tech. 2014;27(4):240-4.
Kim IS, Hong JT, Lee JJ, Lee JB, Cho CB, Yang SH, et al. A Novel Technique for Cervical Laminoplasty Fusion: Simultaneously Enhancing Stabilization and Decompression in Various Cervical Myelopathies: A Technical Note and Outcomes. World Neurosurg. 2018;111:361-6.
Kim GU, Lee GW. Selective blocking laminoplasty in cervical laminectomy and fusion to prevent postoperative C5 palsy. Spine J. 2019;19(4):617-23.
Schmeiser G, Schilling C, Grupp TM, Papavero L, Püschel K, Kothe R. Unilateral laminoplasty with lateral mass screw fixation for less invasive decompression of the cervical spine: a biomechanical investigation. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2015;24(12):2781-7.
Lopez WY, Goh BC, Upadhyaya S, Ziino C, Georgakas PJ, Gupta A, et al. Laminoplasty-an underutilized procedure for cervical spondylotic myelopathy. Spine J. 2021;21(4):571-7.

No competing interests reported.

Download PDF

Reviewers agreed at journal
18 Aug, 2024
Reviewers invited by journal
16 Jul, 2024
Editor invited by journal
25 Jun, 2024
Editor assigned by journal
24 Jun, 2024
Submission checks completed at journal
24 Jun, 2024
First submitted to journal
22 Jun, 2024

You are reading this latest preprint version

Effects of two posterior procedures for treatment of cervical hyperextension injury with multilevel spinal stenosis: A retrospective study

Status:

Version 1

Abstract

Figures

Background

Methods

Patient population

Surgical procedures

Statistical Analysis

Results

Discussion

Conclusion

Abbreviations

Declarations

References

Additional Declarations

Status:

Version 1