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Posterior arch screw for Type II odontoid fracture - An alternative procedure
Journal Pre-proof Posterior arch screw for Type II odontoid fracture - An alternative procedure Dr. K. Ragurajaprakash, M.D., MRCS., DNB(Surg)., MCh(neuro), Dr. Junya Hanakita, M.D., Ph.D, Dr. Toshiyuki Takahashi, M.D., Ph.D, Dr Manabu Minami, M.D., Ph.D, Dr. Yoshitaka Tsujimoto, M.D., Dr. Ryo Kanematsu, M.D. PII:
S1878-8750(20)30279-5
DOI:
https://doi.org/10.1016/j.wneu.2020.02.014
Reference:
WNEU 14289
To appear in:
World Neurosurgery
Received Date: 12 November 2019 Revised Date:
2 February 2020
Accepted Date: 3 February 2020
Please cite this article as: Ragurajaprakash K, Hanakita J, Takahashi T, Minami M, Tsujimoto Y, Kanematsu R, Posterior arch screw for Type II odontoid fracture - An alternative procedure, World Neurosurgery (2020), doi: https://doi.org/10.1016/j.wneu.2020.02.014. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Elsevier Inc. All rights reserved.
TITLE Posterior arch screw for Type II odontoid fracture - An alternative procedure Corresponding Author / First author 1. Dr. Ragurajaprakash K, M.D., MRCS., DNB(Surg)., MCh(neuro) Department of Neurosurgery, Royal care super speciality hospital , Neelambur, Coimbatore, Tamilnadu, India -641062. Phone: +91 9865002156; 91-422- 2227000 / 4040000 Co-Authors 2. Dr. Junya Hanakita, M.D., Ph.D Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 3. Dr. Toshiyuki Takahashi, M.D., Ph.D Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 4. Dr.Manabu Minami, M.D., Ph.D Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 5. Dr. Yoshitaka Tsujimoto, M.D., Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 6. Dr. Ryo Kanematsu, M.D., Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289
Posterior arch screw for Type II odontoid fracture - An alternative procedure Introduction Odontoid fractures can be treated in numerous ways, according to the need of the patient and depending upon the expertise of the surgeon. It starts from conservative measures, includes various immobilisation techniques, followed by challenging fusion procedures either anteriorly or posteriorly. Type II odontoid fractures are difficult to plan especially in case of the presence of associated fractures of atlantoaxial joint. Posterior fusion of Atlantoaxial by transarticular screws (TAS) introduced by Magerl in 1979 and later modified by Goel-Harms technique 7. Both can be used for various disease of Atlantoaxial joint 8, including trauma, tumor, infection, congenital anomalies,
inflammatory diseases and acquired surgical deformities 8. In difficult situations,
such as anomalous vertebral artery, risk of vessel injury is higher, leading to neurological deficits or a catastrophic event.. Lateral mass screw placement, pars screw placement and pedicle screw placement some times may have risk of VA injury , especially in high riding vertebral artery (HRVA), narrow C2 pedicle, and presence of arcuate foramen. To overcome potential injury to VA and to avoid profuse bleeding from venous plexus, C1 posterior arch screw (PAS) 9 and C2 laminar screw (LS) 9 was designed by many surgeons. The starting point for C1 screw insertion is the dorsal aspect from one side and the trajectory facing the other side, so that entire screw lies with in the boundaries of posterior arch. Broad arch is the only prerequisite for C1 PAS placement
9
. Screws in this structures are easy to place without any issues. Hence we combined C1
PAS and C2 LS, for selected cases (where we had difficulties due to VA anomaly, HRVA, atlantoaxial joint fracture on one side alone) with ipsilateral TAS fixation. To enhance the Atlantoaxial fusion, we added autograft placement between C1-C2 lamina according to Brook’s method and sublaminar tapping .
Case 1
We had 67 years old female, referred to our hospital with Type II odontoid fracture, with oblique fracture line and no displacement of fracture. She was investigated with cervical spine x-ray, CT cervical spine, MRI cervical spine, and CT angiogram. She had vertebral artery anomaly persistent first intersegmental artery (PFIA) on left side. Right side vertebral artery showed normal course. Our aim of the surgery is to obtain Atlantoaxial fusion without neurological deficit. When only one normal variant of VA is present on one side , injury to another anomalous VA may be catastrophic, so we planned for unilateral TAS on right side, combined with the same side C1 PAS and C2 LS. To augment bony fusion, modified Brook’s procedure with sublaminar tapping was combined. Post operatively she had been followed up regularly, without neurological deficit (Figure 1).
Case 2 Second case referred to our hospital, as Type II odontoid fracture, with displacement. 68 years old female who had bilateral hand paresthesia, difficulties in fine movements of hands , and clumsiness . MRI, CT cervical spine shows configuration resembling os odontoidium, and also HRVA, which was confirmed by CT angiogram. To avoid injury to VA , in this case fusion was planned on the left side.( Left TAS / same side C1 PAS / same side C2 LS / same side modified Brook’s procedure with sublaminar tapping). This patient improved clinically, recovering from neurological deficits.
Follow up CT cervical spine shows fusion of C2 , and MRI resolving spi-
nal cord intramedullary signals (Figure 2).
Case 3
87 years old female, presented with neck pain and restricted neck movements. Diagnosed as Type II odontoid fracture, with displacement and associated with left lateral atlantoaxial joint disruption. She was referred to our hospital for further management. Due to disruption of left lateral atlantoaxial joint , screw placement in that region may worsen the displacement, hence planned for unilateral right TAS / same side C1 PAS / same side C2 LS / same side modified Brook’s procedure with sublaminar tapping. Post operatively she recovered well without neurological deficit (Figure 3).
Discussion We reported three cases of type II C2 odontoid fracture, which were treated by unilateral TAS combined with unilateral C1 PAS and C2 LS augmented by modified Brook’s procedure 12 and sublaminar tapping . In literature review of surgical procedures for atlantoaxial fusion, GoelHarms and TAS were widely performed. Both techniques can be applied for various kinds of atlantoaxial disorders such as trauma, tumors, infection, congenital anomalies and acquired degenerative diseases. A good fusion rate with satisfactory post-operative clinical course has been reported by many authors. However , in by this methods , the risk of injury of the spinal cord and vertebral artery must be always taken into consideration. Particularly, when the vertebral artery is injured by the screw, fatal event can occur. To avoid this catastrophic complication, meticulous examination about the morphology of axis pedicle, the presence of arcuate foramen, the width of C2 pedicle screw and the position of the vertebral artery, so called HRVA, must be performed before the adoption of this procedure. HRVA was recognised 20% 13 in general population. Literature review of prevalence of HRVA and narrow C2 pedicle ( Table 1). When such morphological situation could not permit the application of Atlantoaxial
fusion by Goel-Harms and TAS method, alternative procedures must be adopted.
Brook’s method has been performed for many years, where the risk of VA injury is less. But in this method, the stability of Atlantoaxial joint is not so enough, that an external fixation method such as Halo-vest must be added for three months. Widely accepted surgical method is Goel-Harms method. In this procedure, C1 lateral mass screw, and C2 pedicle screw are placed, where good clinical results have been reported by many authors. However, in this method, the risk of VA injury must be considered during the C2 pedicle screw insertion. Another alternative procedure is the method where the translaminar screw method are placed instead of pedicle screw. In this method , the risk of VA injury is extremely rare compared with TAS method and Goel-Harms method. In a cadaveric study using biomechanical testing method, satisfactory result has been reported by C1 PAS / C2 LS system. To perform C1 PAS / C2 LS procedure, the diameter of C1 posterior arch must be calculated preoperatively on CT scan. According to the report using CT scan, adequate C1 posterior arch diameter (more than 4.5mm) was demonstrated in 75.8% of 502 patients 16. In the present series, only unilateral TAS screw could be placed. Because of vertebral artery anomaly: PFIA ( case 1), HRVA ( case 2), and atlantoaxial joint disruption ( case 3), on the another side, we performed C1 PAS and C2 LS, adding the modified Brook’s method with sublaminar tapping to enhance Atlantoaxial fixation. On follow up CT scan , good bony fusion of the fractured C2 odontoid process was confirmed in all three cases with good clinical postoperative course. The operative procedures described in the present paper can be performed safely even by the young surgeons without a specific navigation system. We think this surgical technique could be applied for the Atlantoaxial fixation as an alternate procedure. Literature review of C1 PAS / C2 LS usage ( Table 2). The unilateral TAS with unilateral C1 PAS / C2 LS enhanced with Brook’s method / sublaminar tapping applied for three patients of the present study is worth publishing, in view of alternate methods of fusion for odontoid fracture.
Conclusion We would like to present this case series, to highlight the alternate method of fusion techniques in difficult situations of Atlantoaxial fusion. C1 PAS and C2 LS, either unilateral or bilateral will have good fusion results as stand alone procedure. when this fixation procedure is combined with modified Brook’s method, and sublaminar tapping fusion rate could be much higher. In the present series, same side TAS Atlantoaxial screw , was combined with C1 PAS / C2 LS, adding modified Brook’s method with sublaminar tapping. This alternative surgical procedure, which can be easily performed even by young surgeons with no specific navigation system, seems to be worth publishing.
Conflict of Interest The author reports no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.
References
1. Manish Kundanmal Kothari, Samir Surendranath Dalvie, Santosh Gupta, Agnivesh Tikoo, Deepak Kumar Singh. C2 Pedicle Width, Pars Length, and Laminar ickness in Concurrent Ipsilateral Ponticulus Posticus and HighRiding Vertebral Artery:A Radiological Computed Tomography Scan-Based Study . Asian Spine J. 2019 Apr; 13(2): 290–295
2. Uchino A, Saito N, Watadani T, et al. Vertebral artery variations at the C1-2 level diagnosed by magnetic resonance angiography. Neuroradiology 2012;54(1):19–23.
3. Madawi AA, Casey ATH, Solanki GA, et al. Radiological and anatomical evaluation of the atlantoaxial transarticular screw fixation technique. J Neu- rosurg 1997;86:961– 8.
4. Guo-Xin Jin, MD, Huan Wang, PhD, Lei Li, PhD, Shao-Qian Cui, PhD, and Jing-Zhu Duan, MD.C1 posterior arch crossing screw fixation for atlantoaxial joint instability.Spine (Phila Pa 1976). 2013 Oct 15;38(22):E1397-404.
5. Guo-Xin J, Huan W. Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1-2 pedicle screw system as salvage fixation for atlantoaxial instability. J Neurosurg Spine. 2016 Feb;24(2):315-320.
6. Curtis A. Dickman, M.D., Neil R. Crawford, Ph.D., And Christopher G. Paramore, M. Biomechanical characteristics of C1–2 cable fixations. J Neurosurg 85:316–322, 1996.
7. Mummaneni PV, Haid RW. Atlantoaxial fixation: overview of all techniques. Neurol India. 2005 Dec;53(4):408-15.
8. Haid RW. C1-C2 Transrticular Screw Fixation: Technical Aspects. Neurosurg 2001; 49:71-74.
9. Takashi Tsuji, Kazuhiro Chiba, Yosuke Horiuchi, Tadahisa Urabe, Shota Fujita, Morio Matsumoto. Atlantoaxial
Stabilization Using C1 and C2 Laminar Screw Fixation. Asian Spine J 2017;11(2):314-318
10. Guo-Xin Jin, MD, Huan Wang, PhD, Lei Li, PhD, Shao-Qian Cui, PhD, and Jing-Zhu Duan, MD. C1 posterior arch crossing screw fixation for atlantoaxial joint instability.Spine (Phila Pa 1976). 2013 Oct 15;38(22):E1397-404.
11. Dickman CA, Sonntag VK, Papadopoulos SM, Hadley MN. The Interior Spinous Method of Posterior Atlantoaxial Arthrodesis. J Neurosurg 1991;74:190-198.
12. Smith MD, Phillips WA, Hensinger RN. Complications of Fusion to the Upper Cervical Spine. Spine 1991; 16:702-705
13. Wiwat Wajanavisit, amrong Lertudomphonwanit, Praman Fuangfa, Pongsthorn Chanplakorn, Chaiwat Kraiwa anapong, Supaneewan Jaovisidha. Prevalence of High-Riding Vertebral Artery and Morphometry of C2 Pedicles Using a Novel Computed Tomography Reconstruction Technique. Asian Spine J 2016; 10(6) P :1141-1148
14. Yeom JS, Buchowski JM, Kim HJ, Chang BS, Lee CK, Riew KD. Risk of vertebral artery injury: comparison between C1-C2 transarticular and C2 pedicle screws. Spine J 2013; 13:775-85.
15. Yamazaki M, Okawa A, Furuya T, et al. Anomalous vertebral arteries in the extra- and intraosseous regions of the craniovertebral junction visualized by 3-dimensional computed tomographic angiogra- phy: analysis of 100 consecutive surgical cases and review of the literature. Spine (Phila Pa 1976) 2012; 37:E1389-97.
16. Yew A, Lu D, Lu DC. CT-based morphometric analysis of C1 laminar dimensions: C1 translaminar screw fixation is a feasible technique for salvage of atlantoaxial fusions. Surg Neurol Int 2015; 6 :S236-9.
17. Donnellan MB, Sergides IG, Sears WR. Atlantoaxial stabilization using multiaxial C-1 posterior arch screws. J Neurosurg Spine 2008; 9 :522-7.
18. Baaj AA, Vrionis FD. Atlantoaxial stabilization utilizing atlas translaminar fixation. J Clin Neurosci 2010; 17:1578-80.
Figure / Table legends
Figure 1 - Pre op and post op pictures of case 1. Figure 2 - Pre op and post op pictures of case 2. Figure 3 - Pre op and post op pictures of case 3.
Table 1 - Literature review of prevalence of HRVA and narrow C2 pedicle. Table 2 - Literature review of C1 PAS / C2 LS usage in various centers.
Asian Spine J 2016;10(6) :1 1 4 1 -1 1 48
P r e v a le n c
( Table 1 ) Study
Literature review of prevalence of HRVA and narrow C2 pedicle No of patients
Study pattern
Prevalance of HRVA
Associated C2 narrow pedicle
200
CT(TPCT)
16.5%
22.8%
Madawi et al 3
25
Cadaveric study
20%
20%
Yeom et al 14
261
CT
14.5%
9.5%
Yamazaki et al 15
100
3D-CTA
31%
NA
Wiwat Wajanavisit et al 13
( Table 2 )
Literature review of C1 PAS / C2 LS usage
Study
No of cases
C1 PAS / C2 LS Usage
Indications
Takashi tsuji et al 9
Two cases
One side C1PAS / C2 LS has been used
One case FIA Other case VA trauma
Yew et al 16
One case
Both sides C1 PAS / C2 LS has been used
Os odontoideum with VA anomaly
Donnellan et al 17
Three cases
Only B/L C1 PAS used B/L C2 pars screw
Two cases OA One case trauma
Baaj et al 18
One case
One side C1PAS / other side C1 LMS. B/L C2 pars screw has been used
Tumour invasion of C1 lateral mass
Abbreviations C1C2
- Atlantoaxial joint
CT
- Computer tomography
HRVA
- High riding vertebral artery
LS
- Laminar screw
MRI
- Magnetic resonance imaging
PAS
- Posterior arch screw
PFIA
- Persistant first intersegmental artery
PICA
- Posterior inferior cerebellar artery
TAS
- Transarticular screw
VA
- Vertebral artery
.
Credit author statements Ragurajaprakash kirubakaran: ideas, editing, project resources Junya Hanakita: Supervision and editing Toshiyuki Takahasai: supervision, editing, project resources Yoshitaka Tsujimoto: project resources Ryo Kanematsu: project resources
S1878-8750(20)30279-5
DOI:
https://doi.org/10.1016/j.wneu.2020.02.014
Reference:
WNEU 14289
To appear in:
World Neurosurgery
Received Date: 12 November 2019 Revised Date:
2 February 2020
Accepted Date: 3 February 2020
Please cite this article as: Ragurajaprakash K, Hanakita J, Takahashi T, Minami M, Tsujimoto Y, Kanematsu R, Posterior arch screw for Type II odontoid fracture - An alternative procedure, World Neurosurgery (2020), doi: https://doi.org/10.1016/j.wneu.2020.02.014. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Elsevier Inc. All rights reserved.
TITLE Posterior arch screw for Type II odontoid fracture - An alternative procedure Corresponding Author / First author 1. Dr. Ragurajaprakash K, M.D., MRCS., DNB(Surg)., MCh(neuro) Department of Neurosurgery, Royal care super speciality hospital , Neelambur, Coimbatore, Tamilnadu, India -641062. Phone: +91 9865002156; 91-422- 2227000 / 4040000 Co-Authors 2. Dr. Junya Hanakita, M.D., Ph.D Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 3. Dr. Toshiyuki Takahashi, M.D., Ph.D Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 4. Dr.Manabu Minami, M.D., Ph.D Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 5. Dr. Yoshitaka Tsujimoto, M.D., Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289 6. Dr. Ryo Kanematsu, M.D., Spinal Disorders Center, Fujieda Heisei Memorial Hospital 123-1 Mizukami, Fujieda City, Shizuoka 426-8662, Japan Phone: 81-54-643-1230; FAX: 81-54-643-1289
Posterior arch screw for Type II odontoid fracture - An alternative procedure Introduction Odontoid fractures can be treated in numerous ways, according to the need of the patient and depending upon the expertise of the surgeon. It starts from conservative measures, includes various immobilisation techniques, followed by challenging fusion procedures either anteriorly or posteriorly. Type II odontoid fractures are difficult to plan especially in case of the presence of associated fractures of atlantoaxial joint. Posterior fusion of Atlantoaxial by transarticular screws (TAS) introduced by Magerl in 1979 and later modified by Goel-Harms technique 7. Both can be used for various disease of Atlantoaxial joint 8, including trauma, tumor, infection, congenital anomalies,
inflammatory diseases and acquired surgical deformities 8. In difficult situations,
such as anomalous vertebral artery, risk of vessel injury is higher, leading to neurological deficits or a catastrophic event.. Lateral mass screw placement, pars screw placement and pedicle screw placement some times may have risk of VA injury , especially in high riding vertebral artery (HRVA), narrow C2 pedicle, and presence of arcuate foramen. To overcome potential injury to VA and to avoid profuse bleeding from venous plexus, C1 posterior arch screw (PAS) 9 and C2 laminar screw (LS) 9 was designed by many surgeons. The starting point for C1 screw insertion is the dorsal aspect from one side and the trajectory facing the other side, so that entire screw lies with in the boundaries of posterior arch. Broad arch is the only prerequisite for C1 PAS placement
9
. Screws in this structures are easy to place without any issues. Hence we combined C1
PAS and C2 LS, for selected cases (where we had difficulties due to VA anomaly, HRVA, atlantoaxial joint fracture on one side alone) with ipsilateral TAS fixation. To enhance the Atlantoaxial fusion, we added autograft placement between C1-C2 lamina according to Brook’s method and sublaminar tapping .
Case 1
We had 67 years old female, referred to our hospital with Type II odontoid fracture, with oblique fracture line and no displacement of fracture. She was investigated with cervical spine x-ray, CT cervical spine, MRI cervical spine, and CT angiogram. She had vertebral artery anomaly persistent first intersegmental artery (PFIA) on left side. Right side vertebral artery showed normal course. Our aim of the surgery is to obtain Atlantoaxial fusion without neurological deficit. When only one normal variant of VA is present on one side , injury to another anomalous VA may be catastrophic, so we planned for unilateral TAS on right side, combined with the same side C1 PAS and C2 LS. To augment bony fusion, modified Brook’s procedure with sublaminar tapping was combined. Post operatively she had been followed up regularly, without neurological deficit (Figure 1).
Case 2 Second case referred to our hospital, as Type II odontoid fracture, with displacement. 68 years old female who had bilateral hand paresthesia, difficulties in fine movements of hands , and clumsiness . MRI, CT cervical spine shows configuration resembling os odontoidium, and also HRVA, which was confirmed by CT angiogram. To avoid injury to VA , in this case fusion was planned on the left side.( Left TAS / same side C1 PAS / same side C2 LS / same side modified Brook’s procedure with sublaminar tapping). This patient improved clinically, recovering from neurological deficits.
Follow up CT cervical spine shows fusion of C2 , and MRI resolving spi-
nal cord intramedullary signals (Figure 2).
Case 3
87 years old female, presented with neck pain and restricted neck movements. Diagnosed as Type II odontoid fracture, with displacement and associated with left lateral atlantoaxial joint disruption. She was referred to our hospital for further management. Due to disruption of left lateral atlantoaxial joint , screw placement in that region may worsen the displacement, hence planned for unilateral right TAS / same side C1 PAS / same side C2 LS / same side modified Brook’s procedure with sublaminar tapping. Post operatively she recovered well without neurological deficit (Figure 3).
Discussion We reported three cases of type II C2 odontoid fracture, which were treated by unilateral TAS combined with unilateral C1 PAS and C2 LS augmented by modified Brook’s procedure 12 and sublaminar tapping . In literature review of surgical procedures for atlantoaxial fusion, GoelHarms and TAS were widely performed. Both techniques can be applied for various kinds of atlantoaxial disorders such as trauma, tumors, infection, congenital anomalies and acquired degenerative diseases. A good fusion rate with satisfactory post-operative clinical course has been reported by many authors. However , in by this methods , the risk of injury of the spinal cord and vertebral artery must be always taken into consideration. Particularly, when the vertebral artery is injured by the screw, fatal event can occur. To avoid this catastrophic complication, meticulous examination about the morphology of axis pedicle, the presence of arcuate foramen, the width of C2 pedicle screw and the position of the vertebral artery, so called HRVA, must be performed before the adoption of this procedure. HRVA was recognised 20% 13 in general population. Literature review of prevalence of HRVA and narrow C2 pedicle ( Table 1). When such morphological situation could not permit the application of Atlantoaxial
fusion by Goel-Harms and TAS method, alternative procedures must be adopted.
Brook’s method has been performed for many years, where the risk of VA injury is less. But in this method, the stability of Atlantoaxial joint is not so enough, that an external fixation method such as Halo-vest must be added for three months. Widely accepted surgical method is Goel-Harms method. In this procedure, C1 lateral mass screw, and C2 pedicle screw are placed, where good clinical results have been reported by many authors. However, in this method, the risk of VA injury must be considered during the C2 pedicle screw insertion. Another alternative procedure is the method where the translaminar screw method are placed instead of pedicle screw. In this method , the risk of VA injury is extremely rare compared with TAS method and Goel-Harms method. In a cadaveric study using biomechanical testing method, satisfactory result has been reported by C1 PAS / C2 LS system. To perform C1 PAS / C2 LS procedure, the diameter of C1 posterior arch must be calculated preoperatively on CT scan. According to the report using CT scan, adequate C1 posterior arch diameter (more than 4.5mm) was demonstrated in 75.8% of 502 patients 16. In the present series, only unilateral TAS screw could be placed. Because of vertebral artery anomaly: PFIA ( case 1), HRVA ( case 2), and atlantoaxial joint disruption ( case 3), on the another side, we performed C1 PAS and C2 LS, adding the modified Brook’s method with sublaminar tapping to enhance Atlantoaxial fixation. On follow up CT scan , good bony fusion of the fractured C2 odontoid process was confirmed in all three cases with good clinical postoperative course. The operative procedures described in the present paper can be performed safely even by the young surgeons without a specific navigation system. We think this surgical technique could be applied for the Atlantoaxial fixation as an alternate procedure. Literature review of C1 PAS / C2 LS usage ( Table 2). The unilateral TAS with unilateral C1 PAS / C2 LS enhanced with Brook’s method / sublaminar tapping applied for three patients of the present study is worth publishing, in view of alternate methods of fusion for odontoid fracture.
Conclusion We would like to present this case series, to highlight the alternate method of fusion techniques in difficult situations of Atlantoaxial fusion. C1 PAS and C2 LS, either unilateral or bilateral will have good fusion results as stand alone procedure. when this fixation procedure is combined with modified Brook’s method, and sublaminar tapping fusion rate could be much higher. In the present series, same side TAS Atlantoaxial screw , was combined with C1 PAS / C2 LS, adding modified Brook’s method with sublaminar tapping. This alternative surgical procedure, which can be easily performed even by young surgeons with no specific navigation system, seems to be worth publishing.
Conflict of Interest The author reports no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.
References
1. Manish Kundanmal Kothari, Samir Surendranath Dalvie, Santosh Gupta, Agnivesh Tikoo, Deepak Kumar Singh. C2 Pedicle Width, Pars Length, and Laminar ickness in Concurrent Ipsilateral Ponticulus Posticus and HighRiding Vertebral Artery:A Radiological Computed Tomography Scan-Based Study . Asian Spine J. 2019 Apr; 13(2): 290–295
2. Uchino A, Saito N, Watadani T, et al. Vertebral artery variations at the C1-2 level diagnosed by magnetic resonance angiography. Neuroradiology 2012;54(1):19–23.
3. Madawi AA, Casey ATH, Solanki GA, et al. Radiological and anatomical evaluation of the atlantoaxial transarticular screw fixation technique. J Neu- rosurg 1997;86:961– 8.
4. Guo-Xin Jin, MD, Huan Wang, PhD, Lei Li, PhD, Shao-Qian Cui, PhD, and Jing-Zhu Duan, MD.C1 posterior arch crossing screw fixation for atlantoaxial joint instability.Spine (Phila Pa 1976). 2013 Oct 15;38(22):E1397-404.
5. Guo-Xin J, Huan W. Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1-2 pedicle screw system as salvage fixation for atlantoaxial instability. J Neurosurg Spine. 2016 Feb;24(2):315-320.
6. Curtis A. Dickman, M.D., Neil R. Crawford, Ph.D., And Christopher G. Paramore, M. Biomechanical characteristics of C1–2 cable fixations. J Neurosurg 85:316–322, 1996.
7. Mummaneni PV, Haid RW. Atlantoaxial fixation: overview of all techniques. Neurol India. 2005 Dec;53(4):408-15.
8. Haid RW. C1-C2 Transrticular Screw Fixation: Technical Aspects. Neurosurg 2001; 49:71-74.
9. Takashi Tsuji, Kazuhiro Chiba, Yosuke Horiuchi, Tadahisa Urabe, Shota Fujita, Morio Matsumoto. Atlantoaxial
Stabilization Using C1 and C2 Laminar Screw Fixation. Asian Spine J 2017;11(2):314-318
10. Guo-Xin Jin, MD, Huan Wang, PhD, Lei Li, PhD, Shao-Qian Cui, PhD, and Jing-Zhu Duan, MD. C1 posterior arch crossing screw fixation for atlantoaxial joint instability.Spine (Phila Pa 1976). 2013 Oct 15;38(22):E1397-404.
11. Dickman CA, Sonntag VK, Papadopoulos SM, Hadley MN. The Interior Spinous Method of Posterior Atlantoaxial Arthrodesis. J Neurosurg 1991;74:190-198.
12. Smith MD, Phillips WA, Hensinger RN. Complications of Fusion to the Upper Cervical Spine. Spine 1991; 16:702-705
13. Wiwat Wajanavisit, amrong Lertudomphonwanit, Praman Fuangfa, Pongsthorn Chanplakorn, Chaiwat Kraiwa anapong, Supaneewan Jaovisidha. Prevalence of High-Riding Vertebral Artery and Morphometry of C2 Pedicles Using a Novel Computed Tomography Reconstruction Technique. Asian Spine J 2016; 10(6) P :1141-1148
14. Yeom JS, Buchowski JM, Kim HJ, Chang BS, Lee CK, Riew KD. Risk of vertebral artery injury: comparison between C1-C2 transarticular and C2 pedicle screws. Spine J 2013; 13:775-85.
15. Yamazaki M, Okawa A, Furuya T, et al. Anomalous vertebral arteries in the extra- and intraosseous regions of the craniovertebral junction visualized by 3-dimensional computed tomographic angiogra- phy: analysis of 100 consecutive surgical cases and review of the literature. Spine (Phila Pa 1976) 2012; 37:E1389-97.
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Figure / Table legends
Figure 1 - Pre op and post op pictures of case 1. Figure 2 - Pre op and post op pictures of case 2. Figure 3 - Pre op and post op pictures of case 3.
Table 1 - Literature review of prevalence of HRVA and narrow C2 pedicle. Table 2 - Literature review of C1 PAS / C2 LS usage in various centers.
Asian Spine J 2016;10(6) :1 1 4 1 -1 1 48
P r e v a le n c
( Table 1 ) Study
Literature review of prevalence of HRVA and narrow C2 pedicle No of patients
Study pattern
Prevalance of HRVA
Associated C2 narrow pedicle
200
CT(TPCT)
16.5%
22.8%
Madawi et al 3
25
Cadaveric study
20%
20%
Yeom et al 14
261
CT
14.5%
9.5%
Yamazaki et al 15
100
3D-CTA
31%
NA
Wiwat Wajanavisit et al 13
( Table 2 )
Literature review of C1 PAS / C2 LS usage
Study
No of cases
C1 PAS / C2 LS Usage
Indications
Takashi tsuji et al 9
Two cases
One side C1PAS / C2 LS has been used
One case FIA Other case VA trauma
Yew et al 16
One case
Both sides C1 PAS / C2 LS has been used
Os odontoideum with VA anomaly
Donnellan et al 17
Three cases
Only B/L C1 PAS used B/L C2 pars screw
Two cases OA One case trauma
Baaj et al 18
One case
One side C1PAS / other side C1 LMS. B/L C2 pars screw has been used
Tumour invasion of C1 lateral mass
Abbreviations C1C2
- Atlantoaxial joint
CT
- Computer tomography
HRVA
- High riding vertebral artery
LS
- Laminar screw
MRI
- Magnetic resonance imaging
PAS
- Posterior arch screw
PFIA
- Persistant first intersegmental artery
PICA
- Posterior inferior cerebellar artery
TAS
- Transarticular screw
VA
- Vertebral artery
.
Credit author statements Ragurajaprakash kirubakaran: ideas, editing, project resources Junya Hanakita: Supervision and editing Toshiyuki Takahasai: supervision, editing, project resources Yoshitaka Tsujimoto: project resources Ryo Kanematsu: project resources