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 Table of Contents  
ORIGINAL ARTICLES
Year : 2022  |  Volume : 5  |  Issue : 2  |  Page : 215-221

An operative technique for management of neglected bi-facetal cervical dislocations


1 Spine Surgery Department Nanavati Max Super Speciality Hospital, Mumbai, Maharashtra, India
2 Orthopaedic Department, Barod Hospital, Indore, Madhya Pradesh, India

Date of Submission05-Jul-2021
Date of Decision30-Oct-2021
Date of Acceptance22-Nov-2021
Date of Web Publication08-Jun-2022

Correspondence Address:
Pawar Jayesh
Spine Surgery Department, Nanavati Max Super Speciality Hospital, 5 Sv Road, Vile Parle (W), Mumbai 400056, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/isj.isj_60_21

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  Abstract 

Background: Bi-facetal cervical dislocations can be missed due to misinterpretation of clinical signs and radiographs at initial assessment. In such cases, an ensuing fibrous union makes reduction and surgical stabilization both difficult and challenging. Multiple-stage approaches are required for its management. The guidelines for the surgical treatment of neglected bi-facetal dislocation are not yet clearly defined. The aim of this retrospective case series is to discuss the operative approach for the management of neglected bi-facetal cervical dislocation and the assessment of its clinical outcomes. Methods and Materials: From 2014 to 2019, five patients with neglected bi-facetal cervical dislocation were surgically treated in two stages by the posterior-anterior approach and were followed up for one year. The average age was 47.4 years, with a mean delay of 9.8 weeks. A posterior approach was preferred first, where a reduction was achieved with the help of lateral mass reduction screws after soft tissue release and facetectomy. This was followed by anterior discectomy and stabilization. Neck pain was assessed by the neck disability index (NDI) and the Visual analogue score (VAS). Neurology was assessed by using the modified Japanese Orthopaedic Association (mJOA) score. Sagittal alignment and fusion were also recorded. Results: Anatomical reduction was achieved in all patients without neurological worsening. NDI, VAS and mJOA score were significantly improved after the surgery. In all patients, complete fusion occurred at the final follow-up and no complications were encountered. Conclusion: It is difficult to reduce a neglected bi-facetal dislocation. Liberal facetectomy and the use of reduction lateral mass screws provides for a safe and controlled reduction. The reported two-stage technique successfully achieves an anatomical reduction and a stable circumferential fusion.

Keywords: Neglected cervical dislocations, posterior-anterior approach, reduction


How to cite this article:
Jayesh P, Mihir B, Amandeep G, Patel B, Arpit U. An operative technique for management of neglected bi-facetal cervical dislocations. Indian Spine J 2022;5:215-21

How to cite this URL:
Jayesh P, Mihir B, Amandeep G, Patel B, Arpit U. An operative technique for management of neglected bi-facetal cervical dislocations. Indian Spine J [serial online] 2022 [cited 2022 Jul 1];5:215-21. Available from: https://www.isjonline.com/text.asp?2022/5/2/215/346972




  Introduction Top


Untreated bi-facetal cervical dislocations are rare. Spinal cord injury is the most common presentation in these cases, which ultimately leads to its diagnosis. Rarely, when the spinal cord injury is spared, tell-tale signs such as persistent neck spasm, brachialgia, and facial injuries arouse suspicion. These injuries may be missed due to the misinterpretation of clinical signs and radiographs at initial assessment.[1] Sometimes, a shoulder contour may obscure the detection of a dislocation below C4 vertebra on a plain radiograph. In these patients, a CT scan is of diagnostic importance. A reduced bi-facetal dislocation can re-dislocate during conservative treatment if not monitored with serial radiographs. A neglected dislocation remains unstable and has a potential risk of delayed spinal cord injury. It is unclear as to whether these dislocations spontaneously stabilize if left untreated. However, in neglected dislocations, an ensuing fibrous union makes reduction and surgical stabilization both difficult and challenging. The guidelines for surgical treatment of neglected bi-facetal dislocation are not clearly defined. We report a series of five cases of these rare injuries. The steps in the surgical management and outcomes are elaborated in this study along with a review of the literature.


  Materials and Methods Top


We analyzed the records of five patients with neglected bi-facetal dislocation who were surgically treated between 2014 and 2019. The average age was 47.4 years (39–59 years). There were no associated injuries. The mean interval between trauma and diagnosis was 9.8 weeks (7–14 weeks). In two patients, the dislocations were missed on plain radiographs after the primary injury and were treated with a soft collar and anti-inflammatory medications. In one patient, the dislocation was reduced in a trauma center, and it re-dislocated before the patient was referred to the author’s institution. There were no serial radiographs to accurately determine the exact time of re-dislocation, as the patient had been lost on follow-up at the initial center. The remaining two patients had deferred treatment after their injury due to minimal physical incapacity and were not diagnosed initially.

In all five patients, neck pain and restriction of the range of movements of the cervical spine were the chief complaints at presentation. Three patients presented with a recent worsening of neurology (1–4 weeks), out of whom two patients had myelopathy and one patient had right-side grip weakness with radiculopathy [Table 1]. This was not recorded in their previous treatment. The higher functions of these patients were normal.
Table 1: Clinical details of the patients

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Plain radiographs (sitting AP, lateral and dynamic views) were obtained. In three patients, the level of the shoulder overlapped the dislocation. A CT scan and MRI revealed a bi-facetal dislocation. Two patients had unilateral facet fractures; three patients showed a significant disc protrusion. Spinal cord edema was seen in three patients. All five patients showed anterior translation of more than 50% of the cranial over the caudal vertebra [Figure 1] and [Figure 2].
Figure 1: Case 1: A 59-year-old man with C3/4 bifacetal dislocation of 8 weeks duration. (A) Lateral radiograph at presentation. (B–D) CT scan cuts through the right facet joint, the central vertebral body, and the left facet joint, respectively. (E) Postoperative lateral radiograph demonstrating a reduction of dislocation by the posterior-anterior approach

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Figure 2: Case 2: A 39-year-old man with C4/5 bifacetal dislocation of 7 weeks duration. (A) Lateral radiograph at presentation. (B–D) CT scan cuts through the right facet joint, the vertebral body, and the left facet joint, respectively. (E) Postoperative lateral radiograph showing restoration of normal sagittal alignment by the posterior-anterior approach

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Intraoperative traction under anesthesia

As per the protocol at the author’s institution, awake preoperative traction was not used. An attempt at reduction under anesthesia was preferred with neuro-monitoring guidance.[2] All patients were placed in the supine position on a head rest. A Gardner Wells tong was used. Traction was applied by using weights. The distraction of the dislocated segment was closely monitored with a C-arm. A reduction maneuver using flexion to unlock the facets and then an attempted reduction in extension was tried.[3],[4] In all five cases, three attempts with incremental weights proved unsuccessful. The procedure was then abandoned.

Operative procedure

In all patients, the posterior approach was preferred first. The patient was placed in the prone position on a horse-shoe head rest. Traction was applied through the Gardner Wells tong for stability. The posterior surgical dissection was limited to the dislocated segment. The capsule of the dislocated joint and the intra-articular fibrosis was excised. On both sides, the superior edge of the superior facet of the caudal vertebra was resected with a pneumatic scalpel [Figure 3]. The “locked” inferior facets of the cranial vertebra were visualized, which was partially resected to disengage the facets. A foraminotomy protected the exiting roots from undue traction during reduction. A reduction maneuver, using a towel clip on the spinous processes of the vertebrae to apply a distraction and a translation force, was attempted.[5] This was aided by a bone scoop introduced over the edge of the superior facet to pull back the inferior facets.[6] In all five cases, this proved unsuccessful.
Figure 3: Superior facet resection (black arrow) on bone model

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Long polyaxial “reduction screws” were introduced in the cranial lateral masses [Figure 4]. A standard lateral mass screw was used in the caudal lateral mass. The trajectory of the screw in the lateral mass should lie diagonally from the postero-medial-inferior corner to the antero-lateral-superior corner with a bi-cortical purchase. A mildly pre-contoured lordotic rod was locked in the caudal screw. With the caudal lateral mass as the lever fulcrum, the rod was then slowly introduced and captured in the cranial screws. This reduced the facets into their anatomical location [Figure 5]. The neuro-monitoring signals were normal throughout the reduction.
Figure 4: (A) Model. (B) Fluoroscopic image of polyaxial reduction screw insertion in the lateral mass

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Figure 5: (A) Precountered rod locked in the caudal vertebra that acts as a lever fulcrum for reduction. (B) As the set screw of the cranial vertebra was locked, the screw head was pulled upward toward the rod. (C) Complete reduction was achieved

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The patient was then placed in a supine position. A left anterior-lateral exposure of the target disc space was performed. A complete discectomy and excision of the posterior longitudinal ligament was done. Fragments posterior to the PLL were removed. The spinal cord was decompressed. A measured cage filled with autologous bone was placed and stabilized with a locking plate-screw construct [Figure 6]. Only one cervical segment was fused in this study.
Figure 6: Fluoroscopy image of the lateral cervical spine showing a cervical plate and a cage applied

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Measurements

The neck pain of patients was assessed by VAS and NDI. The preoperative scores were compared with postoperative scores at 6 weeks and at the final follow-up of 12 months [Table 2]. The radiological measurements were done by an independent radiologist. The preoperative kyphosis angle, postoperative reduction, loss of correction, sagittal alignment, implant migration/loosening, construct failure, and fusion were assessed [Table 2]. The neurological status was assessed by using the modified JOA score at 6 weeks and 12 months [Table 3]. The total blood loss, surgical time (including intraoperative closed reduction maneuver), and hospital stay were also recorded [Table 4].
Table 2: Pre- and postoperative radiological measurements and pain assessment by visual analog score (VAS) and neck disability index (NDI)

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Table 3: Pre- and postoperative neurological assessment of the patients

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Table 4: Perioperative parameters and hospital stay

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  Results Top


All patients were operated under general anesthesia in a single stage by two approaches (posterior and anterior). The reduction was carried out by the posterior approach with the help of a long poly axial reduction screw, and the anterior approach was used for stabilization and fusion. The neural monitoring signals were intact throughout the procedure in all the cases. The mean operating time was 303 min (285 to 330), and the mean blood loss was 172 mL (150–200) [Table 4]. All patients were subsequently discharged on the fourth postoperative day with a soft collar for 6 weeks. The patients were followed for one year.

The mean preoperative kyphosis -37.2 degree corrected in all patients after the surgery to mean postoperative 1.6 degree and maintained over a mean one degree throughout one-year follow-up [Table 2]. This result showed that all patients achieved sagittal alignment and the reduction was well maintained until fusion.

The mean preoperative VAS score was 6.6, which improved to 3.4 postoperatively at 6 weeks and 1.6 at one year follow-up. Similarly, the mean preoperative NDI score was 67.2, which improved to 21.2 at one year follow-up. Both NDI and VAS scores were significantly improved after surgery at last follow-up, as compared with the preoperative score (P < 0.05) [Table 2]. The average preoperative mJOA score was 16.2, which improved to 17 postoperatively at 6 weeks and 18 at one year follow-up. Three patients with neurological involvement had completely improved at the final follow-up [Table 3].

There were no cage or implant-related problems observed intraoperatively and postoperatively up to the final follow-up. Before the final follow-up, fusion occurred in all cases, without a loss of reduction as confirmed on serial radiographs.


  Discussion Top


A bi-facetal dislocation is the end-point of instability in the cervical spine. The flexion distraction force first disrupts the posterior facets and musculo-ligamentous complex and then moves anteriorly to injure the disc and supporting longitudinal ligaments.[8],[9] These injuries are highly unstable, endangering the spinal cord until they are eventually surgically stabilized. Most patients present with varying degrees of spinal cord injury. This necessitates urgent reduction and surgical stabilization. A bi-facetal dislocation can be reduced in most cases, with controlled traction.[3] It is important that this reduction is monitored with serial radiographs for 12 weeks.[10],[11] Re-dislocation during conservative treatment is not uncommon and may be missed.[7],[12] In our study, one patient presented with re-dislocation as he was not monitored with serial radiographs at the initial center. Incomplete reduction where both facets were not reduced anatomically can result in a re-dislocation. Also, facet fractures can cause a re-dislocation. A high index of suspicion is, therefore, required to prevent a neglected dislocation, particularly in patients with normal neurological and minimal clinical signs.

The shoulder contour can obscure cervical spine injuries.[8],[13] In our series, the dislocation was missed in three patients; however, two patients did not seek medical attention due to minimal physical incapacity. The injury was visible on a standard sitting lateral radiograph in only two out of five patients. Since the neck pain did not resolve, a CT scan was obtained, which revealed a bi-facetal dislocation. Plain radiographs have been replaced by a CT scan in most trauma centers, as the investigation of choice in patients with polytrauma.[14] In developing countries, it is not uncommon for patients to be evaluated with radiographs in primary centers.[6]

A missed bi-facetal dislocation more than 3 weeks old is termed as a neglected dislocation.[6],[15] This time frame exemplifies the difficulty in achieving a closed reduction. The inferior facet of the cranial vertebra button-holes through the capsule and locks in front of the superior facet of the caudal vertebra. Fibrosis that ensues consolidates this position and impedes reduction.[15],[16] Fibrosis is probably an early attempt to gain secondary stability. This fragile secondary stability does not protect the spinal cord from delayed trauma. A new neurological deficit was observed in three out of the five patients in our series. It is unclear whether a spontaneous fusion ensues. In all five patients, no bony fusion was observed on the CT scan at presentation to the author’s institution.

The longer the delay in treatment, the more difficult it gets to achieve a closed reduction. Hasan et al.,[15] in a series of 12 dislocations delayed up to 3.5 months, used traction preoperatively for one week. When reduction was not achieved, a posterior facetectomy was done to achieve reduction. If this was unsuccessful, traction was applied again for a week before the anterior plating. Similarly Shrivastava et al.[5] employed preoperative traction for 3 weeks before attempting an open reduction. The mean delay in our series was 9.8 weeks. We preferred to administer traction under general anesthesia, with the advantages of having relaxed muscles and neuromonitoring assistance, but this proved unsuccessful in all the patients. Shrivastava et al.[5] described an open reduction maneuver with towel clips anchored on the spinous processes of the cranial and caudal vertebrae. This proved unsuccessful in our series, with the anchors pulling out in three out of five patients. So, the authors preferred a controlled reduction using long reduction lateral mass screws. The rod was locked in the caudal screw first. This acts as the fulcrum for the reduction. The reduction screws in the cranial lateral mass then allowed a controlled reduction over a pre-contoured lordotic rod. The bi-cortical purchase and diagonal trajectory of the screw provides better bony purchase as compared with other conventional techniques of fixation.[16] The average age of patients in this series was 47.5 years and had good bone stock for the reduction. The implants could be limited to the affected segment. Several other authors had mentioned liberal facetectomy to be the pivotal step in achieving reduction.

The ultimate goal was to achieve anatomical reduction and stable fusion of dislocated spinal segments, without fusing functional spinal segments. In order to achieve reduction, sufficient anterior and posterior soft tissue release was mandatory and to achieve stable fusion, circumferential stabilization was necessary. So for such cases a combined approach is the only solution.

Bartels Donk, Payer M Tessitore E, and Kamran Farooque preferred to conduct an anterior discectomy prior to the posterior reduction maneuver for the management of neglected cases.[17],[18],[19] The surgical plan was three-staged (anterior-posterior-anterior) (posterior-anterior-posterior), which increased operative time, increased blood loss, resulted in bed rest during the entire course of traction, and led to a longer hospital stay. This was probably important if there was evidence of osseous union on the preoperative CT scans (none in our series). Srivastava[20] treated a case of fused bi-facetal dislocation of 14 months duration, by a three-staged (posterior-anterior-posterior) approach. Circumferential release of the fusion mass was important to achieve reduction.

Jain[6] and Liu[7] carried out a two-staged (posterior-anterior) procedure for the management of neglected bi-facetal dislocation. They used the posterior approach first for facetectomy and interspinous wiring, which allowed partial reduction. This was followed by the anterior approach for stabilization and final reduction. They reported residual listhesis of 1 mm to 2 mm and loss of correction in two patients postoperatively. Liu[7] emphasized the need for a circumferential stability. Kim[21] showed greater stability with a posterior rod screw construct and anterior plating. In our series, complete reduction was achieved through the posterior approach alone with the help of reduction screws and a rod. In the absence of bony fusion, a liberal facetectomy disengages the dislocation and protects the exiting roots. The anterior surgery was done to complete a circumferential fusion. All patients achieved bony fusion before the final follow-up without loss of reduction. Perhaps the use of a lateral mass screw and rod posteriorly, along with a cage and plate anteriorly in our technique, would have helped to provide a rigid construct.

Stretching of the disc annulus due to the antero-listhesis produced a pseudo-disc protrusion. This did not impede reduction. At the time of presentation, there were no extruded or sequestrated fragments of the disc, which are contraindications for this method. It might be a possibility that preservation of the disc acted as a restraint against further dislocation and protected against spinal cord injury. After a complete reduction using lateral mass screws, the stretch on the annulus was reduced. We did not have any neurological worsening during reduction in our series.

Conclusion

It is difficult to reduce a neglected bi-facetal dislocation. Liberal facetectomy and the use of reduction lateral mass screws provides for a safe and controlled reduction. The reported two-stage technique successfully achieves an anatomical reduction and a stable circumferential fusion.

Ethical policy and institutional review board statement

The article being a retrospective study was exempted from ethical approval.

Patient Declaration Statement

There was no need of patient consent as the study analyzed the patients records only.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Hassan MG Treatment of old dislocations of the lower cervical spine. Int Orthop 2002;26:263-7.  Back to cited text no. 15
    
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Rathinavelu S, Islam A, Shivhare P, Chatterjee S. Lateral mass screw fixation in the cervical spine: Introducing a new technique. Asian Spine J2020. doi: 10.31616/asj.2020.0143.  Back to cited text no. 16
    
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Bartels RH, Donk R Delayed management of traumatic bilateral cervical facet dislocation: Surgical strategy. Report of three cases. J Neurosurg 2002;97:362-5.  Back to cited text no. 17
    
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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