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CASE REPORT
Year : 2022  |  Volume : 70  |  Issue : 4  |  Page : 1658--1660

Traumatic Floating Neural Arch of the Subaxial Cervical Spine: Case Report

Khaled Hadhri, Mohamed Ben Salah, Mehdi Bellil, Mondher Kooli 
 Department of Orthopedics and Traumatology, Charles Nicolle's Hospital, Tunis, Tunisia

Correspondence Address:
Khaled Hadhri
Spine Unit; Department of Orthopedics and Traumatology, Charles Nicolle's Hospital, Boulevard 9 Avril, 1006, Tunis
Tunisia

Abstract

Bilateral traumatic pedicle fracture in the lower cervical spine is a very unusual lesion. Its association with bilateral facet dislocation has been reported once in the literature. We report a unique traumatic lesion considered as subaxial cervical floating neural arch with special emphasize on reduction maneuvers and surgical management. It was a case of bilateral C7 pedicle fracture with bilateral C6/C7 facet dislocation in a neurologically intact 70-year-old patient. Open posterior reduction with fixation followed by anterior fusion was performed with good functional and radiological outcomes at last follow up. The floating neural arch lesion is the combination of bilateral pedicle fracture and facet dislocation. The detection of such lesions imposes a two-stage surgery with open posterior reduction and anterior fusion.



How to cite this article:
Hadhri K, Salah MB, Bellil M, Kooli M. Traumatic Floating Neural Arch of the Subaxial Cervical Spine: Case Report.Neurol India 2022;70:1658-1660


How to cite this URL:
Hadhri K, Salah MB, Bellil M, Kooli M. Traumatic Floating Neural Arch of the Subaxial Cervical Spine: Case Report. Neurol India [serial online] 2022 [cited 2022 Nov 29 ];70:1658-1660
Available from: https://www.neurologyindia.com/text.asp?2022/70/4/1658/355120


Full Text



Bilateral traumatic pedicle fracture in the lower cervical spine is a very unusual lesion. Its association with facet dislocation has been reported once in the literature. We present a unique case of a neurologically intact 70-year-old man who sustained a C7 bilateral pedicle fracture with C6/C7 facet dislocation. Besides the rareness of the lesion, the interest of our report is to discuss the reduction method and surgical management of such cases.

 Case History



A 70-year-old unbelted driver of a vehicle which skidded in a road traffic accident presented with isolated cervical spine injury. The patient complained of neck pain without loss of motor or sensory function. Initial physical examination revealed a frontal skull contusion; the Glasgow Coma Scale was 15. The neurological examination was normal and vital signs were unremarkable. Neck examination elicited posterior midline tenderness to palpation without deformities. Cervical spine computed tomography sagittal reconstructions showed bilateral facet dislocation at C6/C7 level with unstable spondylolisthesis of C6 over C7 and indirect signs of disc disruption [Figure 1] and [Figure 2]. The axial views demonstrated bilateral C7 pedicle fracture [Figure 3]. As manual closed manipulation under general anesthesia failed to reduce the dislocation, we took the decision to perform posterior open reduction with osteosynthesis. The patient was placed in prone position; the dislocated facets of C7 were exposed through a posterior midline approach. A gradual distraction of the involved laminas with controlled hyperflexion positioning and careful tire-lever maneuver has achieved complete facet reduction, which was confirmed at lateral fluoroscopy. Bilateral lateral mass screws were then inserted into C6, C7, and T1, and rods were locked in neutral position. Anterior approach was then performed. After C6/C7 discectomy, a tricortical graft from anterior iliac crest was inserted and anterior cervical plating was performed. The patient did not develop any neurological complication or wound infection. At 1-year follow-up, the patient was symptom free and lateral plain X-ray showed good stability and signs of fusion [Figure 4].{Figure 1}{Figure 2}{Figure 3}{Figure 4}

 Discussion and Conclusions



Bilateral pedicle fracture of the lower cervical spine is a very uncommon injury. Only three cases have been reported in the English literature.[1],[2],[3] The first report was described by Dunn in 1974[1] concerning a 20-year-old patient who presented with isolated cervical injury with no initial neurological deficit after a road traffic accident. The injury was similar to our report with a C7 bilateral pedicle fracture associated with a complete dislocation of the neural arch. The patient underwent an open posterior reduction and C6-T1 stabilization after unsuccessful reduction attempt with skull traction and development of triceps weakness. Dunn has considered this injury to be related to a combination of extension and rotational forces.[1] We think that this lesion, such as in our case, may be consistent with sudden hyperflexion responsible for bilateral facet dislocation sharply followed by the compressive extension mechanism causing impaction and separation of the dislocated neural arch. Isolated bilateral pedicle fracture of the subaxial cervical spine has been described twice in the literature.[2],[3] Phipatanakul has reported a unique case of multilevel bilateral pedicle fracture in a 22-year-old woman involved in a motor–vehicle collision.[2] The injury was probably due to the compressive extension mechanism as mentioned in the Allen's classification[4] and was treated by a staged anterior then posterior stabilization. In 2012, Salem has reported a case of bilateral pedicle fracture of the subaxial cervical spine occurring after a low energy trauma to a 63-year-old woman.[3] The patient was treated conservatively by a 3-month hard collar immobilization. The injury was explained to be the result of significant degeneration accompanied by osteoporosis and a transmission of the load through the posterior elements in a compressive extension mechanism. In our case, the closed reduction was not successful because of the floating character of the C7 neural arch; it was then mandatory to perform an open posterior reduction. In addition to that, it was uncertain whether an open anterior reduction could be efficient, transdiscal distraction does not appear to have any effect on the posterior elements in such cases. When possible, closed reduction appears to be a relatively safe method if performed on an awake and alert patient.[5],[6] It seems to be safer than manipulation under anesthesia with 1% permanent neurological complication rate.[6] Vaccaro estimates that open reduction, closed traction reduction using minimal weight or closed reduction under anesthesia is related to higher frequency of neurological worsening than higher weight traction.[7] This may be due to more disc extrusion than if initial disk space distraction is achieved with progressive high weight traction. Prereduction MRI could be helpful for diagnosing a spinal epidural hematoma, a herniated intervertebral disc or a direct compression to the cord.[6],[7] In our case, the neurological status was verified after a wake-up-test because of the unavailability of spinal cord evoked potential monitoring. Neurological monitoring is an extremely helpful method especially during anterior reduction maneuvers of neurologically intact patients.[8] In our case, the combination of anterior fusion after posterior stabilization was necessary regarding the indirect signs of disk damage and the extreme instability of the lesion. The posterior stabilization method could ideally include lateral mass screws at C6 associated with C7 pedicle screw fixation, which is considered to be biomechanically superior to C7 lateral mass fixation.[9] This option would have the advantage of being across the fractured pedicle creating osteosynthesis. With such screws, the construct could be stopped at C7 without including T1, as an additional anterior fixation is anyway added. Because of the unavailability of long polyaxial 3.5 mm screws to be inserted through C7 pedicles, we were forced to perform lateral mass fixation with extension to T1 which had transitional shape and could therefore welcome lateral mass screws.

In conclusion, bilateral pedicle fracture of the subaxial cervical spine is a very rare injury. Its combination with bilateral facet dislocation has been reported once in the literature.

The pattern of this lesion appears to be a combination of sudden hyperflexion followed by the compressive extension mechanism. This case outlines, besides the rareness of the lesion, the necessity of immediate open posterior reduction due to the extreme mobility and the floating character of the subaxial dislocated neural arch.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Dunn EJ. Fracture-dislocation of the posterior elements of C7 associated with bilateral pedicle fractures of C7: A case report. J Trauma 1974;14:527-36.
2Phipatanakul WP, Minster GJ. Fractures of the second through the fifth cervical vertebra with multilevel bilateral pedicle involvement. A case report. J Bone Joint Surg Am 2003;85-A: 1347-50.
3Salem KM, Grevitt MP. A bilateral C7 pedicle fracture following a low energy injury. Injury 2012;43:513-6.
4Allen BL Jr, Ferguson RL, Lehmann TR, O'Brien RP. A mechanistic classification of closed, indirect fractures and dislocations of the lower cervical spine. Spine 1982;7:1-27.
5Ludwig SC, Vaccaro AR, Balderston RA, Cotler JM. Immediate quadriparesis after manipulation for bilateral cervical facet subluxation. J Bone Joint Surg Am 1997;79A: 587-90.
6Gelb DE, Hadley MN, Aarabi B, Dhall SS, Hurlbert RJ, Rozzelle CJ, et al. Initial closed reduction of cervical spinal fracture-dislocation injuries. Neurosurgery 2013;72(Suppl 2):73-83.
7Vaccaro AR, Falatyn SP, Flanders AE, Balderston RA, Northrup BE, Cotler JM. Magnetic resonance evaluation of the intervertebral disc, spinal ligaments, and spinal cord before and after closed traction reduction of cervical spine dislocations. Spine 1999;24:1210-7.
8Du W, Wang C, Tan J, Shen B, Ni S, Zheng Y. Management of subaxial cervical facet dislocation through anterior approach monitored by spinal cord evoked potential. Spine 2014;39:48-52.
9Hong JT, Tomoyuki T, Udayakumar R, Espinoza Orías AA, Inoue N, An HS. Biomechanical comparison of three different types of C7 fixation techniques. Spine (Phila Pa 1976) 2011;36:393-8.