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Anterior pedicle spreader reduction for unilateral cervical facet dislocation
G Model JINJ 7296 No. of Pages 5
Injury, Int. J. Care Injured xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
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Anterior pedicle spreader reduction for unilateral cervical facet dislocation Zhengfeng Zhang Department of Orthopedics, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Street, Shapingba District, Chongqing 400037, China
A R T I C L E I N F O
Keywords: Unilateral cervical facet dislocation Reduction Anterior pedicle spreader
A B S T R A C T
Objective: The anterior only surgical procedure including discectomy, open reduction and fusion is used as a recommended approach in the treatment of unilateral cervical facet dislocations, but is difficult to achieve satisfactory anterior open reduction by vertebra distractor to spread the facet joints, especially for delayed management of unilateral cervical facet dislocation (7–21 days). The goal of this study was to report an anterior pedicle spreader technique to distract directly the facet joint for anterior reduction and the results of 4 patients with successful application and describe safety. Methods: Four patients with unilateral cervical facet dislocation who failed to open anterior reduction by vertebra spreader procedure were surgically treated by the anterior pedicle spreader reduction. In these 4 patients (3 males and 1 female), the distribution of spine level was from C4/5 to C6/7; the neurological status was comprised 2 patients with ASIA E, 1 with D and 1 with A; the surgical management was ranged from 7 to 18 days. After discectomy, if failed to open anterior reduction procedure, the anterior pedicle spreader was inserted along the pedicle axis with the fluoroscope-assisted view imaging. The spreader was distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment. Results: Postoperatively, all patients had obtained successful reduction and satisfactory anatomic sagittal alignment. There was no complication owing to the use of this technique. The ASIA A showed no neurological improvement; the patient with ASIA D was improved neurologically to ASIA E; no ASIA E patients showed neurological deterioration. Conclusions: Anterior pedicle spreader reduction represents an efficacious but technically challenging option for the delayed treatment of unilateral cervical facet dislocation. © 2017 Elsevier Ltd. All rights reserved.
Introduction Unilateral cervical facet dislocations represent 5% of substantial cervical spine injuries and are treated surgically with decompression, reduction, fixation and fusion. The treatment of cervical facet dislocations is highly variable including anterior alone, posterior alone, anterior-posterior, posterior-anterior, and anterior-posterior-anterior approaches according to closed, anterior open or posterior open reduction [1,2]. Among these approaches, the anterior only approach including discectomy, open reduction and instrumental fusion are recommended, especially for presence of a traumatic intervertebral disc herniation but without spinal cord injury [2–7]. It carries less risk for spinal cord injury compared with the closed reduction or posterior alone approach, and minimizes the surgical injury and operative time compared with posterior reduction followed with anterior fusion. However, it is
E-mail addresses: [email protected], [email protected] (Z. Zhang).
difficult to achieve satisfactory reduction using an anterior approach and about 25% to 40% anterior open reductions failed requiring posterior surgery, because the vertebra distractor failed to spread the facet joints [4,8]. We have therefore developed an anterior pedicle spreader technique to distract directly the facet joints for reduction of unilateral facet dislocation. This technique is especially useful for delayed management of unilateral facet dislocation with traumatic intervertebral disc herniation patients who failed the conventional anterior open reduction to avoid a posterior procedure. We have performed this procedure on 4 patients with satisfactory outcomes. Patients and methods During the 3-year period from January 2013 to December 2015, 15 patients with unilateral cervical facet dislocations were admitted or transferred to and treated surgically in the investigator’s group (Z. Z.). Among them, 11 patients who presented no traumatic intervertebral disc herniation underwent a closed
http://dx.doi.org/10.1016/j.injury.2017.07.006 0020-1383/© 2017 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Z. Zhang, Anterior pedicle spreader reduction for unilateral cervical facet dislocation, Injury (2017), http://dx. doi.org/10.1016/j.injury.2017.07.006
G Model JINJ 7296 No. of Pages 5
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Z. Zhang / Injury, Int. J. Care Injured xxx (2017) xxx–xxx
4 mm in diameter and 14 or 16 mm in length [11]. Postoperatively, a cervical hard collar was used to protect patient’s neck for 6 weeks. The accuracy of pedicle screw placement was examined postoperatively by reviewing axial CT scans (1 mm slice thickness).
reduction attempt in an awake or under general anesthesia with Gardner-Wells traction. 5 of these 11 patients achieved a successful closed reduction. The remaining 6 patients who failed to closed reduction and other 4 patients who presented a traumatic intervertebral disc herniation underwent open anterior reduction by typical vertebra spreader procedure after discectomy [4]. Among these 10 patients, 4 patients (4/10, 40%) failed to open anterior reduction by vertebra spreader procedure and treated by the anterior pedicle spreader reduction. In these 4 patients (3 males and 1 female), the distribution of spine level was from C4/5 to C6/7; the neurological status was comprised 2 patients with ASIA E, 1 with D and 1 with A; the surgical management was ranged from 7 to 18 days; follow-up ranged from 12 to 18 months (Table 1). Before and after surgery, all patients underwent CT scans to define the precise spinal injury, spinal alignment and fusion, and a 1.5-T MRI to define cord compression and the extent of intramedullary signal intensity change by sagittal and axial planes, T1weighted and T2-weighted MRIs signal. Standard AP, lateral and two oblique films were obtained before and after surgery to assess spinal injury, reduction, and instruments. Neurological status of all patients on admission and at each follow-up was evaluated according to the International Standards for Neurological and Functional Classification of Spinal Cord Injury determined by ASIAIMSOP [9]. All operations were performed by the author (Z. Z.). After discectomy, if an anterior open reduction by vertebra spreader procedure was failed, anterior pedicle spreader was inserted along the pedicle axis with the fluoroscope-assisted view imaging, which was similar as previous protocol [10,11]. Briefly, with one rotated carm, an accurate AP and lateral view with endplate overlapping of the surgical level of the cervical spine were set on to obtain the cranial or caudal angle of inclination of pedicle axis and facet dislocation (Fig. 1A). Two oblique views with maximized circular portion of the pedicle cortex and maximized length of pedicle were set on to obtain the pedicle axis inclination and unilateral facet dislocation (Fig. 1B). The pedicle ipsilateral to the facet dislocation is the one that is supposed to be cannulated. The centre of the cortical circular area visualized with the image intensifier indicated the insertion point of the spreader on the vertebral body. The contralateral oblique view confirmed the cranial or caudal angle of inclination. The entry hole was created with a 1.8 mm straight awl. With the definite angle of inclination from the sagittal and coronal plane, the awl inserted to posterior margin of vertebral (usually 1.7 cm), which was situated at the circular area by the oblique views (Fig. 1C and D). A 1.4 mm guidewire of cannulated screw was inserted into the pedicle cavity using a drill, and was confirmed repeatedly on AP, lateral and pedicle axis views by fluoroscopy (Fig. 1E and F). After inserting guidewire, anterior pedicle spreader was performed (Fig. 1G). With an intervertebra spacer, the spreader was distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment (Figs. 1H and 2 ). After reduction and insertion of an autogenous bone cage, an anterior cervical plate or an anterior cervical pedicle screw plate (Z3; Wego; Weihai, Shandong, China) was used for fixation (Fig. 1I and J). The pedicle screws were 4 mm in diameter and 30, 32 or 34 mm in length. The vertebral screw was
Results The clinical data are summarized in Table 1. Mean operative time was 115 min (range 90–130 min) and average blood loss was 93 ml (range 50–210 ml). All patients achieved anterior reduction. The patients with ASIA E and D were permitted to ambulate the next day with a cervical collar. Pre- and postoperative plain radiographs and MR and CT images showed good cervical alignment (Fig. 1K, L, M, N, S, T) and accurate placement of pedicle screws within the pedicle cortex (Fig. 1Q and R). The patients achieved successful spinal fusion 3 months postoperatively by plain radiographs and CT scan. There was no complication or instrument failure owing to the use of this technique. The ASIA A patient showed no neurological improvement; the patient with ASIA D was improved neurologically to ASIA E; 2 patients with ASIA E showed no neurological deterioration. Discussion The typical anterior reduction is using a Caspar vertebral body pin retractors, an intervertebra poker or a laminar spreader inserted into the disc space for axial traction to reduce dislocated joints, under fluoroscopic guidance and with or without spinal cord monitoring. Once the facet joints are cleared, the instrument is pushed in a caudad direction or/and cephalad rotated to achieve posterior translation of the upper segment [4,7]. However, this distraction is only spread to vertebra but not to facet joints directly, that is the reason for reduction failed. Even in setting of technique to insert the distractor as far posteriorly as possible to the posterior wall of the upper vertebra, or to place the Caspar retractor pins in a slight amount of kyphosis manner during the distraction maneuver, the anterior reduction is failed ranging from 25% to 40% [4,8]. The present technique not only distracts directly to the facet joint but also pushes the facet joint directly in a caudad direction (Fig. 3). A satisfactory outcome of reduction was observed in patients who failed to open anterior reduction by vertebra spreader procedure, as indicated by restored saggittal alignment (Fig. 2). Comparing the closed reduction with Gardner-Wells traction, which success rates are reported ranging from 30% to 100% [12– 15], the present technique takes less risk for spinal cord injury especially for presence of a traumatic intervertebral disc herniation but without spinal cord injury. Although posterior- only approach for reduction and fusion affords the greater stability by posterior instrumentation [16], it cannot allow for removal of extruded disc material before reduction of a dislocated segment, which maybe a potential risk of spinal cord injury [6,17,18]. Comparing posterior reduction with anterior-posterior, posterioranterior, and anterior-posterior-anterior approaches, the anterior only approach minimizes the surgical injury and operative time. In case of anterior cervical pedicle fixation, which offers higher threecolumn cervical spine stabilization [19–22], the anterior pedicle
Table 1 Patients data chart. Case NO.
Sex/Age (y)
Levels
Facet fracture
Time to surgery (d)
Pedicle/vertebral Plate
Operation time (min)
ASIA Preop/postop/follow-up(M)
1 2 3 4 Average
M/57 F/47 M/45 M/49 -/49.5
C5/6 C4/5 C5/6 C6/7 –
N Y Y Y –
14 18 9 7 12
V P P P –
90 130 120 120 115
E/E/18 E/E/12 D/E/12 A/A/12 –
Please cite this article in press as: Z. Zhang, Anterior pedicle spreader reduction for unilateral cervical facet dislocation, Injury (2017), http://dx. doi.org/10.1016/j.injury.2017.07.006
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Z. Zhang / Injury, Int. J. Care Injured xxx (2017) xxx–xxx
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Fig. 1. Imaging studies of the illustrative case with C6/7 unilateral facet dislocation (case 4). (A, B) Intraoperative lateral radiograph (A) oblique radiograph (B) showing C6/7 unilateral facet dislocation (arrow). (C, D) Intraoperative oblique radiographs showing and confirming the awl inserted in C6 pedicle (arrows). (E, F) Intraoperative oblique radiographs showing the guidewire inserted in C6 pedicle. (G) Intraoperative fluoroscopic radiograph showing the insertion of anterior pedicle spreader along the guidewire. (H) Intraoperative oblique image is showing that the spreader is distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment (arrows). (I, J) Intraoperative fluoroscopic radiographs after C6/7 plate and screw fixation. (K, L)Preoperative (K) and postoperative (L) 3D CT reconstruction images showing the intact C6/7 right facet joint (arrows). (M, N) Preoperative (M) and postoperative (N) 3D CT reconstruction images showing C6/7 dislocation and reduction (arrows). (O, P) Preoperative (O) and postoperative (P) sagittal CT images showing the restoration of saggittal alignment. (Q, R) Postoperative axial CT images demonstrating good placement of anterior pedicle screws at C6 and C7. (S, T) Preoperative (S) and postoperative (T) T2 sagittal images of MR showing spinal cord compression and decompression.
Fig. 2. Illustration of anterior pedicle spreader reduction for unilateral facet dislocation (large cope of Fig. 1H). With an intervertebra spacer as a fulcrum (triangle), the spreader is distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment (arrows).
spreader followed the path of pedicle screw trajectory. In fact, the spreader in the present technique is the tapper of anterior pedicle screw. The technique of anterior pedicle spreader reduction is especially indicated to delayed management (7–21 days) of unilateral facet dislocation patients who failed the conventional anterior open reduction to avoid a posterior procedure. Another indication of present technique is expected fixation by anterior cervical pedicle plate. Once the present technique failed, we recommend anterior facetectomy for reduction of cervical facet dislocation, which procedure is proceeding in same incision with high success rate [23]. Anterior pedicle spreader poses a potential risk for injury to vertebral arteries, the spinal cord or nerve roots during the insertion of spreader. The ideal anterior entrance point of the anterior pedicle identified by oblique fluoroscopy enabled to insert the anterior pedicle spreader into the pedicle accurately. In fact, the safety area at the insertion of the anterior pedicle screws was even larger than that of posterior pedicle screws [24,25]. However, most pedicle wall perforations being non-critical [26–30], the potentially fatal consequences of neurovascular injury during anterior pedicle spreader insertion remain a serious concern. This procedure should be confirmed repeatedly on AP, lateral and
Please cite this article in press as: Z. Zhang, Anterior pedicle spreader reduction for unilateral cervical facet dislocation, Injury (2017), http://dx. doi.org/10.1016/j.injury.2017.07.006
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Z. Zhang / Injury, Int. J. Care Injured xxx (2017) xxx–xxx
Fig. 3. Illustration of the principle of the level for anterior open reduction by Caspar pin retractors (A), laminar spreader (B), intervertebra poker (C) and anterior pedicle spreader (D). Comparing to A, B and C, the anterior pedicle spreader technique (D) not only distracts directly to an intervertebra spacer as a fulcrum (triangle) but also pushes an applied force (arrows) to the facet joint directly in a caudad direction.
pedicle axis views by fluoroscopy, even with real-time navigation computerised system or mobile CT technology. In the addition, the apparent dominance or angiectopia of the vertebral artery in preoperative imaging should also be concerned. Although no misplacement of anterior spreader or anterior screws in this series, it should be acted as a routine procedure only if familiarity with cervical anatomy, as well as experience with special imaging techniques. Although the clinical outcome is promising, there are still several limitations to the study. It is still unknown whether it is indicated to bilateral dislocation or unilateral cervical dislocation for over 3 weeks with severe facet joint fractures. Although eligible cases are hard to be collected, the small sample size (only 4 patients) is certainly another major limitation of the study. In conclusion, the present data demonstrates that anterior pedicle spreader reduction for unilateral cervical dislocation is efficacious. However, familiarity with cervical anatomy and adequate experience with special imaging technique for visualizing the pedicle during surgery are crucial for this procedure. Therefore, this technique should be used only by a highly experienced surgical team. Conflict of interest The author declare no conflict of interest. Acknowledgement None. References [1] Glaser JA, Jaworski BA, Cuddy BG, Albert TJ, Hollowell JP, McLain RF, et al. Variation in surgical opinion regarding management of selected cervical spine injuries. A preliminary study. Spine 1998;23:975–82 discussion 83. [2] Nassr A, Lee JY, Dvorak MF, Harrop JS, Dailey AT, Shaffrey CI, et al. Variations in surgical treatment of cervical facet dislocations. Spine 2008;33(7):E188–93. [3] Piccirilli M, Liberati C, Santoro G, Santoro A. Cervical post-traumatic unilateral locked facets: clinical, radiological and surgical remarks on a series of 33 patients. J Spinal Disord Technol Clin Spine Surg 2016;29(6):261–5.
[4] Reindl R, Ouellet J, Harvey EJ, Berry G, Arlet V. Anterior reduction for cervical spine dislocation. Spine 2006;31(6):648–52. [5] Hart RA. Cervical facet dislocation. When is magnetic resonance imaging indicated? Spine 2002;27:116–7. [6] Doran SE, Papadopoulos SM, Ducker TB, Lillehei KO. Magnetic resonance imaging documentation of coexistent traumatic locked facets of the cervical spine and disc herniation. J Neurosurg 1993;79:341–5. [7] Du 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(1):48–52. [8] Feng G, Hong Y, Li L, Liu H, Pei F, Song Y, et al. Anterior decompression and nonstructural bone grafting and posterior fixation for cervical facet dislocation with traumatic disc herniation. Spine 2012;37(25):2082–8. [9] DiTunno JF, Young W, Creasey G. International standards for neurological and functional classification of spinal cord injury: revised 1992. Paraplegia 1994;32:70–80. [10] Yukawa Y, Kato F, Ito K, Nakashima H, Machino M. Anterior cervical pedicle screw and plate fixation using fluoroscope-assisted pedicle axis view imaging: a preliminary report of a new cervical reconstruction technique. Eur Spine J 2009;18(6):911–6. [11] Zhang Z, Mu Z, Zheng W. Anterior pedicle screw and plate fixation for cervical facet dislocation: case series and technical note. Spine J 2016;16(1):123–9. [12] Vital JM, Gille O, Senegas J, Pointillart V. Reduction technique for uni- and biarticular dislocations of the lower cervical spine. Spine 1998;23:949–54 discussion 955. [13] Grant GA, Mirza SK, Chapman JR, Winn HR, Newell DW, Jones DT, et al. Risk of early closed reduction in cervical spine subluxation injuries. J Neurosurg Spine 1999;90:13–8. [14] Star AM, Jones AA, Cotler JM, Balderston RA, Sinha R. Immediate closed reduction of cervical spine dislocations using traction. Spine 1990;15:1068– 72. [15] Sabiston CP, Wing PC, Schweigel JF, Van Peteghem PK, Yu W. Closed reduction of dislocations of the lower cervical spine. J Trauma 1988;28:832–5. [16] Do Koh Y, Lim TH, Won You J, Eck J, An HS. A biomechanical comparison of modern anterior and posterior plate fixation of the cervical spine. Spine 2001;26:15–21. [17] Grant GA, Mirza SK, Chapman JR, Winn HR, Newell DW, Jones DT, et al. Risk of early closed reduction in cervical spine subluxation injuries. J Neurosurg Spine 1999;90:13–8. [18] Harrington JF, Likavec MJ, Smith AS. Disc herniation in cervical fracture subluxation. Neurosurgery 1991;29:374–9. [19] Koller H, Hempfing A, Acosta F, Fox M, Scheiter A, Tauber M, et al. Cervical anterior transpedicular screw fixation part I: study on morphological feasibility, indications and technical prerequisites. Eur Spine J 2008;17 (4):523–38. [20] Koller H, Acosta F, Tauber M, Fox M, Martin H, Forstner R, et al. Cervical anterior transpedicular screw fixation (ATPS)–part II. Accuracy of manual insertion and pull-out strength of ATPS. Eur Spine J 2008;17(4):539–55. [21] Koller H, Hitzl W, Acosta F, Tauber M, Zenner J, Resch H, et al. In vitro study of accuracy of cervical pedicle screw insertion using an electronic conductivity device (ATPS part III). Eur Spine J 2009;18(9):1300–13.
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Z. Zhang / Injury, Int. J. Care Injured xxx (2017) xxx–xxx [22] Koller H, Schmidt R, Mayer M, Hitzl W, Zenner J, Midderhoff S, et al. The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping. Eur Spine J 2010;19(12):2137–48. [23] Zhang Z, Liu C, Mu Z, Wang H, Shangguan L, Zhang C, et al. Anterior facetectomy for reduction of cervical facet dislocation. Spine 2016;41(7):E403–9. [24] Yukawa Y, Kato F, Ito K, Nakashima H, Machino M. Anterior cervical pedicle screw and plate fixation using fluoroscope-assisted pedicle axis view imaging: a preliminary report of a new cervical reconstruction technique. Eur Spine J 2009;18(6):911–6. [25] Aramomi M, Masaki Y, Koshizuka S, Kadota R, Okawa A, Koda M, et al. Anterior pedicle screw fixation for multilevel cervical corpectomy and spinal fusion. Acta Neurochir (Wien) 2008;150(6)575–82 discussion 582.
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[26] Ito H, Neo M, Yoshida M, Fujibayashi S, Yoshitomi Nakamura T. Efficacy of computer-assisted pedicle screw insertion for cervical instability in RA patients. Rheumatology 2006;27:567–74. [27] Jeanneret B, Gebhard JS, Magerl F. Transpedicular screw fixation of articular mass fracture-separation: results of an anatomical study and operative technique. Spine 1994;19:2529–39. [28] Karaikovic EE, Daubs MD, Madsen RW, Gaines Jr. RW. Morphologic characteristics of human cervical pedicles. Spine 1997;22:493–500. [29] Takahashi J, Shono Z, Nakamura I, Hirabayashi H, Kamimura M, Ebara S, et al. Computer-assisted screw insertion of cervical disorders in rheumatoid arthritis. Eur Spine J 2006;16:485–94. [30] Yoshimoto H, Sato S, Hyakumachi T, Yanagibashi Y, Masuda T. Spinal reconstruction using a cervical pedicle screw system. Clin Orthop Relat Res 2005;431:111–9.
Please cite this article in press as: Z. Zhang, Anterior pedicle spreader reduction for unilateral cervical facet dislocation, Injury (2017), http://dx. doi.org/10.1016/j.injury.2017.07.006
Injury, Int. J. Care Injured xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Anterior pedicle spreader reduction for unilateral cervical facet dislocation Zhengfeng Zhang Department of Orthopedics, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Street, Shapingba District, Chongqing 400037, China
A R T I C L E I N F O
Keywords: Unilateral cervical facet dislocation Reduction Anterior pedicle spreader
A B S T R A C T
Objective: The anterior only surgical procedure including discectomy, open reduction and fusion is used as a recommended approach in the treatment of unilateral cervical facet dislocations, but is difficult to achieve satisfactory anterior open reduction by vertebra distractor to spread the facet joints, especially for delayed management of unilateral cervical facet dislocation (7–21 days). The goal of this study was to report an anterior pedicle spreader technique to distract directly the facet joint for anterior reduction and the results of 4 patients with successful application and describe safety. Methods: Four patients with unilateral cervical facet dislocation who failed to open anterior reduction by vertebra spreader procedure were surgically treated by the anterior pedicle spreader reduction. In these 4 patients (3 males and 1 female), the distribution of spine level was from C4/5 to C6/7; the neurological status was comprised 2 patients with ASIA E, 1 with D and 1 with A; the surgical management was ranged from 7 to 18 days. After discectomy, if failed to open anterior reduction procedure, the anterior pedicle spreader was inserted along the pedicle axis with the fluoroscope-assisted view imaging. The spreader was distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment. Results: Postoperatively, all patients had obtained successful reduction and satisfactory anatomic sagittal alignment. There was no complication owing to the use of this technique. The ASIA A showed no neurological improvement; the patient with ASIA D was improved neurologically to ASIA E; no ASIA E patients showed neurological deterioration. Conclusions: Anterior pedicle spreader reduction represents an efficacious but technically challenging option for the delayed treatment of unilateral cervical facet dislocation. © 2017 Elsevier Ltd. All rights reserved.
Introduction Unilateral cervical facet dislocations represent 5% of substantial cervical spine injuries and are treated surgically with decompression, reduction, fixation and fusion. The treatment of cervical facet dislocations is highly variable including anterior alone, posterior alone, anterior-posterior, posterior-anterior, and anterior-posterior-anterior approaches according to closed, anterior open or posterior open reduction [1,2]. Among these approaches, the anterior only approach including discectomy, open reduction and instrumental fusion are recommended, especially for presence of a traumatic intervertebral disc herniation but without spinal cord injury [2–7]. It carries less risk for spinal cord injury compared with the closed reduction or posterior alone approach, and minimizes the surgical injury and operative time compared with posterior reduction followed with anterior fusion. However, it is
E-mail addresses: [email protected], [email protected] (Z. Zhang).
difficult to achieve satisfactory reduction using an anterior approach and about 25% to 40% anterior open reductions failed requiring posterior surgery, because the vertebra distractor failed to spread the facet joints [4,8]. We have therefore developed an anterior pedicle spreader technique to distract directly the facet joints for reduction of unilateral facet dislocation. This technique is especially useful for delayed management of unilateral facet dislocation with traumatic intervertebral disc herniation patients who failed the conventional anterior open reduction to avoid a posterior procedure. We have performed this procedure on 4 patients with satisfactory outcomes. Patients and methods During the 3-year period from January 2013 to December 2015, 15 patients with unilateral cervical facet dislocations were admitted or transferred to and treated surgically in the investigator’s group (Z. Z.). Among them, 11 patients who presented no traumatic intervertebral disc herniation underwent a closed
http://dx.doi.org/10.1016/j.injury.2017.07.006 0020-1383/© 2017 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Z. Zhang, Anterior pedicle spreader reduction for unilateral cervical facet dislocation, Injury (2017), http://dx. doi.org/10.1016/j.injury.2017.07.006
G Model JINJ 7296 No. of Pages 5
2
Z. Zhang / Injury, Int. J. Care Injured xxx (2017) xxx–xxx
4 mm in diameter and 14 or 16 mm in length [11]. Postoperatively, a cervical hard collar was used to protect patient’s neck for 6 weeks. The accuracy of pedicle screw placement was examined postoperatively by reviewing axial CT scans (1 mm slice thickness).
reduction attempt in an awake or under general anesthesia with Gardner-Wells traction. 5 of these 11 patients achieved a successful closed reduction. The remaining 6 patients who failed to closed reduction and other 4 patients who presented a traumatic intervertebral disc herniation underwent open anterior reduction by typical vertebra spreader procedure after discectomy [4]. Among these 10 patients, 4 patients (4/10, 40%) failed to open anterior reduction by vertebra spreader procedure and treated by the anterior pedicle spreader reduction. In these 4 patients (3 males and 1 female), the distribution of spine level was from C4/5 to C6/7; the neurological status was comprised 2 patients with ASIA E, 1 with D and 1 with A; the surgical management was ranged from 7 to 18 days; follow-up ranged from 12 to 18 months (Table 1). Before and after surgery, all patients underwent CT scans to define the precise spinal injury, spinal alignment and fusion, and a 1.5-T MRI to define cord compression and the extent of intramedullary signal intensity change by sagittal and axial planes, T1weighted and T2-weighted MRIs signal. Standard AP, lateral and two oblique films were obtained before and after surgery to assess spinal injury, reduction, and instruments. Neurological status of all patients on admission and at each follow-up was evaluated according to the International Standards for Neurological and Functional Classification of Spinal Cord Injury determined by ASIAIMSOP [9]. All operations were performed by the author (Z. Z.). After discectomy, if an anterior open reduction by vertebra spreader procedure was failed, anterior pedicle spreader was inserted along the pedicle axis with the fluoroscope-assisted view imaging, which was similar as previous protocol [10,11]. Briefly, with one rotated carm, an accurate AP and lateral view with endplate overlapping of the surgical level of the cervical spine were set on to obtain the cranial or caudal angle of inclination of pedicle axis and facet dislocation (Fig. 1A). Two oblique views with maximized circular portion of the pedicle cortex and maximized length of pedicle were set on to obtain the pedicle axis inclination and unilateral facet dislocation (Fig. 1B). The pedicle ipsilateral to the facet dislocation is the one that is supposed to be cannulated. The centre of the cortical circular area visualized with the image intensifier indicated the insertion point of the spreader on the vertebral body. The contralateral oblique view confirmed the cranial or caudal angle of inclination. The entry hole was created with a 1.8 mm straight awl. With the definite angle of inclination from the sagittal and coronal plane, the awl inserted to posterior margin of vertebral (usually 1.7 cm), which was situated at the circular area by the oblique views (Fig. 1C and D). A 1.4 mm guidewire of cannulated screw was inserted into the pedicle cavity using a drill, and was confirmed repeatedly on AP, lateral and pedicle axis views by fluoroscopy (Fig. 1E and F). After inserting guidewire, anterior pedicle spreader was performed (Fig. 1G). With an intervertebra spacer, the spreader was distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment (Figs. 1H and 2 ). After reduction and insertion of an autogenous bone cage, an anterior cervical plate or an anterior cervical pedicle screw plate (Z3; Wego; Weihai, Shandong, China) was used for fixation (Fig. 1I and J). The pedicle screws were 4 mm in diameter and 30, 32 or 34 mm in length. The vertebral screw was
Results The clinical data are summarized in Table 1. Mean operative time was 115 min (range 90–130 min) and average blood loss was 93 ml (range 50–210 ml). All patients achieved anterior reduction. The patients with ASIA E and D were permitted to ambulate the next day with a cervical collar. Pre- and postoperative plain radiographs and MR and CT images showed good cervical alignment (Fig. 1K, L, M, N, S, T) and accurate placement of pedicle screws within the pedicle cortex (Fig. 1Q and R). The patients achieved successful spinal fusion 3 months postoperatively by plain radiographs and CT scan. There was no complication or instrument failure owing to the use of this technique. The ASIA A patient showed no neurological improvement; the patient with ASIA D was improved neurologically to ASIA E; 2 patients with ASIA E showed no neurological deterioration. Discussion The typical anterior reduction is using a Caspar vertebral body pin retractors, an intervertebra poker or a laminar spreader inserted into the disc space for axial traction to reduce dislocated joints, under fluoroscopic guidance and with or without spinal cord monitoring. Once the facet joints are cleared, the instrument is pushed in a caudad direction or/and cephalad rotated to achieve posterior translation of the upper segment [4,7]. However, this distraction is only spread to vertebra but not to facet joints directly, that is the reason for reduction failed. Even in setting of technique to insert the distractor as far posteriorly as possible to the posterior wall of the upper vertebra, or to place the Caspar retractor pins in a slight amount of kyphosis manner during the distraction maneuver, the anterior reduction is failed ranging from 25% to 40% [4,8]. The present technique not only distracts directly to the facet joint but also pushes the facet joint directly in a caudad direction (Fig. 3). A satisfactory outcome of reduction was observed in patients who failed to open anterior reduction by vertebra spreader procedure, as indicated by restored saggittal alignment (Fig. 2). Comparing the closed reduction with Gardner-Wells traction, which success rates are reported ranging from 30% to 100% [12– 15], the present technique takes less risk for spinal cord injury especially for presence of a traumatic intervertebral disc herniation but without spinal cord injury. Although posterior- only approach for reduction and fusion affords the greater stability by posterior instrumentation [16], it cannot allow for removal of extruded disc material before reduction of a dislocated segment, which maybe a potential risk of spinal cord injury [6,17,18]. Comparing posterior reduction with anterior-posterior, posterioranterior, and anterior-posterior-anterior approaches, the anterior only approach minimizes the surgical injury and operative time. In case of anterior cervical pedicle fixation, which offers higher threecolumn cervical spine stabilization [19–22], the anterior pedicle
Table 1 Patients data chart. Case NO.
Sex/Age (y)
Levels
Facet fracture
Time to surgery (d)
Pedicle/vertebral Plate
Operation time (min)
ASIA Preop/postop/follow-up(M)
1 2 3 4 Average
M/57 F/47 M/45 M/49 -/49.5
C5/6 C4/5 C5/6 C6/7 –
N Y Y Y –
14 18 9 7 12
V P P P –
90 130 120 120 115
E/E/18 E/E/12 D/E/12 A/A/12 –
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Fig. 1. Imaging studies of the illustrative case with C6/7 unilateral facet dislocation (case 4). (A, B) Intraoperative lateral radiograph (A) oblique radiograph (B) showing C6/7 unilateral facet dislocation (arrow). (C, D) Intraoperative oblique radiographs showing and confirming the awl inserted in C6 pedicle (arrows). (E, F) Intraoperative oblique radiographs showing the guidewire inserted in C6 pedicle. (G) Intraoperative fluoroscopic radiograph showing the insertion of anterior pedicle spreader along the guidewire. (H) Intraoperative oblique image is showing that the spreader is distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment (arrows). (I, J) Intraoperative fluoroscopic radiographs after C6/7 plate and screw fixation. (K, L)Preoperative (K) and postoperative (L) 3D CT reconstruction images showing the intact C6/7 right facet joint (arrows). (M, N) Preoperative (M) and postoperative (N) 3D CT reconstruction images showing C6/7 dislocation and reduction (arrows). (O, P) Preoperative (O) and postoperative (P) sagittal CT images showing the restoration of saggittal alignment. (Q, R) Postoperative axial CT images demonstrating good placement of anterior pedicle screws at C6 and C7. (S, T) Preoperative (S) and postoperative (T) T2 sagittal images of MR showing spinal cord compression and decompression.
Fig. 2. Illustration of anterior pedicle spreader reduction for unilateral facet dislocation (large cope of Fig. 1H). With an intervertebra spacer as a fulcrum (triangle), the spreader is distracted directly to the facet joint and pushed in a caudad direction to achieve posterior translation of the upper segment (arrows).
spreader followed the path of pedicle screw trajectory. In fact, the spreader in the present technique is the tapper of anterior pedicle screw. The technique of anterior pedicle spreader reduction is especially indicated to delayed management (7–21 days) of unilateral facet dislocation patients who failed the conventional anterior open reduction to avoid a posterior procedure. Another indication of present technique is expected fixation by anterior cervical pedicle plate. Once the present technique failed, we recommend anterior facetectomy for reduction of cervical facet dislocation, which procedure is proceeding in same incision with high success rate [23]. Anterior pedicle spreader poses a potential risk for injury to vertebral arteries, the spinal cord or nerve roots during the insertion of spreader. The ideal anterior entrance point of the anterior pedicle identified by oblique fluoroscopy enabled to insert the anterior pedicle spreader into the pedicle accurately. In fact, the safety area at the insertion of the anterior pedicle screws was even larger than that of posterior pedicle screws [24,25]. However, most pedicle wall perforations being non-critical [26–30], the potentially fatal consequences of neurovascular injury during anterior pedicle spreader insertion remain a serious concern. This procedure should be confirmed repeatedly on AP, lateral and
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Fig. 3. Illustration of the principle of the level for anterior open reduction by Caspar pin retractors (A), laminar spreader (B), intervertebra poker (C) and anterior pedicle spreader (D). Comparing to A, B and C, the anterior pedicle spreader technique (D) not only distracts directly to an intervertebra spacer as a fulcrum (triangle) but also pushes an applied force (arrows) to the facet joint directly in a caudad direction.
pedicle axis views by fluoroscopy, even with real-time navigation computerised system or mobile CT technology. In the addition, the apparent dominance or angiectopia of the vertebral artery in preoperative imaging should also be concerned. Although no misplacement of anterior spreader or anterior screws in this series, it should be acted as a routine procedure only if familiarity with cervical anatomy, as well as experience with special imaging techniques. Although the clinical outcome is promising, there are still several limitations to the study. It is still unknown whether it is indicated to bilateral dislocation or unilateral cervical dislocation for over 3 weeks with severe facet joint fractures. Although eligible cases are hard to be collected, the small sample size (only 4 patients) is certainly another major limitation of the study. In conclusion, the present data demonstrates that anterior pedicle spreader reduction for unilateral cervical dislocation is efficacious. However, familiarity with cervical anatomy and adequate experience with special imaging technique for visualizing the pedicle during surgery are crucial for this procedure. Therefore, this technique should be used only by a highly experienced surgical team. Conflict of interest The author declare no conflict of interest. Acknowledgement None. References [1] Glaser JA, Jaworski BA, Cuddy BG, Albert TJ, Hollowell JP, McLain RF, et al. Variation in surgical opinion regarding management of selected cervical spine injuries. A preliminary study. Spine 1998;23:975–82 discussion 83. [2] Nassr A, Lee JY, Dvorak MF, Harrop JS, Dailey AT, Shaffrey CI, et al. Variations in surgical treatment of cervical facet dislocations. Spine 2008;33(7):E188–93. [3] Piccirilli M, Liberati C, Santoro G, Santoro A. Cervical post-traumatic unilateral locked facets: clinical, radiological and surgical remarks on a series of 33 patients. J Spinal Disord Technol Clin Spine Surg 2016;29(6):261–5.
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Please cite this article in press as: Z. Zhang, Anterior pedicle spreader reduction for unilateral cervical facet dislocation, Injury (2017), http://dx. doi.org/10.1016/j.injury.2017.07.006