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Mike-Mayer A, Lam K, Morris RP, Barghouthi AA, Travascio F, Latta LL, Lindsey RW. Posterior atlantoaxial fixation of osteoporotic odontoid fracture: biomechanical analysis of the Magerl versus harms techniques in a cadaver model. Spine J 2024:S1529-9430(24)00190-6. [PMID: 38685273 DOI: 10.1016/j.spinee.2024.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 04/09/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
BACKGROUND CONTEXT Odontoid fractures are among the most common cervical spine fractures in the elderly and are associated with increased morbidity and mortality. Clinical evidence suggests improved survival and quality of life after operative intervention compared to nonoperative treatment. PURPOSE This study seeks to examine the stability of an osteoporotic Type II odontoid fracture following posterior atlantoaxial fixation with either the Magerl transarticular fixation technique or the Harms C1 lateral mass screws C2 pedicle screw rod fixation. STUDY DESIGN Biomechanical cadaveric study. METHODS Eighteen cadaveric specimens extending from the cephalus to C7 were used in this study. Reflective marker arrays were attached to C1 and C2 and a single marker on the dens to measure movement of each during loading with C2-C3 and occiput-C1 being allowed to move freely. A biomechanical testing protocol imparted moments in flexion-extension, axial rotation, and lateral bending while a motion capture system recorded the motions of C1, C2, and the dens. The spines were instrumented with either the Harms fixation (n=9) or Magerl fixation (n=9) techniques, and a simulated Type II odontoid fracture was created. Motions of each instrumented spine were recorded for all moments, and then again after the instrumentation was removed to model the injured, non-instrumented state. RESULTS Both Harms and Magerl posterior C1-C2 fixation allowed for C1, C2, and the dens to move as a relative unit. Without fixation the dens motion was coupled with C1. No significant differences were found in X, Y, Z translation motion of the dens, C1 or C2 during neutral zone motions between the Magerl and Harms fixation techniques. There were no significant differences found in Euler angle motion between the two techniques in either flexion-extension, axial rotation, or lateral bending motion. CONCLUSIONS Our findings suggest that both Harms and Magerl fixation can significantly reduce dens motion in Type II odontoid fractures in an osteoporotic cadaveric bone model. CLINICAL SIGNIFICANCE Both Harms and Magerl posterior atlantoaxial fixation techniques allowed for C1, C2, and the dens to move as a relative unit following odontoid fracture, establishing more anatomic stability to the upper cervical spine.
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Affiliation(s)
- Austin Mike-Mayer
- The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA
| | - Kendrick Lam
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA
| | - Randal P Morris
- The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA.
| | - Abeer Al Barghouthi
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA
| | - Francesco Travascio
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA; Department of Mechanical and Aerospace Engineering, University of Miami, 1251 Memorial Dr., Coral Gables, FL, USA; Department of Orthopaedics, University of Miami, 1611 NW 12th Ave #303, Miami, FL, USA
| | - Loren L Latta
- Mount Sinai Medical Center, Max Biedermann Institute for Biomechanics, 4300 Alton Rd., Miami Beach, FL, USA; Department of Orthopaedics, University of Miami, 1611 NW 12th Ave #303, Miami, FL, USA
| | - Ronald W Lindsey
- The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA
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Chang MC, Seok HG, Choo YJ, Lee GW. The Comparison Between Transarticular Screw Fixation and Segmental Screw-Rod Fixation for Posterior Fusion of the C1-2 Segment: A Systematic Review and Meta-Analysis. World Neurosurg 2022; 164:e1007-e1014. [PMID: 35643403 DOI: 10.1016/j.wneu.2022.05.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Both transarticular screw fixation (TAS) and segmental screw-rod fixation (SF) have been widely performed for C1-2 fusion; however, just only small clinical studies and a few meta-analyses comparing the 2 surgical techniques for C1-2 posterior fusion have been reported. METHODS We searched the Cochrane, Embase, and Medline databases for articles comparing the intraoperative and postoperative outcomes of TAS and SF for C1-2 posterior fusion with April 14, 2022, as the publication cutoff date. The odds ratio (OR) and standardized mean difference were used to analyze differences in outcomes between the 2 abovementioned surgical techniques. A P value < 0.05 was considered statistically significant. RESULTS A total of 5101 publications were assessed, and 6 studies were finally included in the study. In terms of the fusion rate, SF produced significantly better outcomes than TAS did (OR = 2.96, P = 0.02). With respect to surgical outcomes, blood loss and operation times were significantly lower in the TAS group than those in the SF group (P = 0.008 and P < 0.00001, respectively). The rate of vertebral artery injury was significantly lower in the SF group than that in the TAS group (OR = 3.95, P = 0.04). However, other complications, such as screw malposition, infection, hardware failure, and nonunion, were not significantly different between the 2 groups. CONCLUSIONS SF showed a greater fusion rate and lower risk of vertebral artery injury than TAS did, but TAS showed less blood loss and lower operation times than SF.
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Affiliation(s)
- Min Cheol Chang
- Department of Physical Medicine and Rehabilitation, Yeungnam University College of Medicine, Yeungnam University Hospital, Daegu, Korea
| | - Hyun-Gyu Seok
- Department of Orthopaedic Surgery, Yeungnam University College of Medicine, Yeungnam University Hospital, Daegu, Korea
| | - Yoo Jin Choo
- Department of Physical Medicine and Rehabilitation, Yeungnam University College of Medicine, Yeungnam University Hospital, Daegu, Korea
| | - Gun Woo Lee
- Department of Orthopaedic Surgery, Yeungnam University College of Medicine, Yeungnam University Hospital, Daegu, Korea.
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Traynelis VC, Fontes RBV, Abode-Iyamah KO, Cox EM, Greenlee JD. Posterior fusion for fragility type 2 odontoid fractures. J Neurosurg Spine 2021; 35:644-650. [PMID: 34388709 DOI: 10.3171/2021.2.spine201645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 02/01/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the outcomes of elderly patients with type 2 odontoid fractures treated with an instrumented posterior fusion. METHODS Ninety-three consecutive patients older than 65 years of age in whom a type 2 odontoid fracture had been treated with a variety of C1-2 posterior screw fixation techniques were retrospectively reviewed. RESULTS The average age was 78 years (range 65-95 years). Thirty-seven patients had an additional fracture, 30 of which involved C1. Three patients had cervical spinal cord dysfunction due to their injury. All patients had comorbidities. The average total hospitalization was 9.6 days (range 2-37 days). There were 3 deaths and 19 major complications, the most common of which was pneumonia. No patient suffered a vertebral artery injury. Imaging studies were obtained in 64 patients at least 12 months postsurgery (mean 19 months). Fusion was assessed by dynamic radiographs in all cases and with a CT scan in 80% of the cases. Four of the 64 patients did not achieve fusion (6.25% overall). All patients in whom fusion failed had undergone C1 lateral mass fixation and C2 pars (1/29, 3.4%) or laminar (3/9, 33.3%) fixation. CONCLUSIONS Instrumented posterior cervical fusions may be performed in elderly patients with acceptable morbidity and mortality. The fusion rate is excellent except when bilateral C2 translaminar screws are used for axis fixation.
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Affiliation(s)
- Vincent C Traynelis
- 1Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
| | - Ricardo B V Fontes
- 1Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
| | | | - Efrem M Cox
- 3Department of Neurosurgery, UNLV School of Medicine, Las Vegas, Nevada; and
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Vakharia VN, Smith L, Tahir Z, Sparks R, Ourselin S, Tucker S, Thompson D. Occipitocervical instrumented fixation utilising patient-specific C2 3D-printed spinal screw trajectory guides in complex paediatric skeletal dysplasia. Childs Nerv Syst 2021; 37:2643-2650. [PMID: 34148128 DOI: 10.1007/s00381-021-05260-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Instability of the craniocervical junction in paediatric patients with skeletal dysplasia poses a unique set of challenges including anatomical abnormalities, poor bone quality, skeletal immaturity and associated general anaesthetic risks. Instrumented fixation provides optimal stabilisation and fusion rates. The small vertebrae make the placement of C2 pedicle screws technically demanding with low margins of error between the spinal canal and the vertebral artery. METHODS We describe a novel clinical strategy utilising 3D-printed spinal screw trajectory guides (3D-SSTG) for individually planned C2 pedicle and laminar screws. The technique is based on a pre-operative CT scan and does not require intraoperative CT imaging. This reduces the radiation burden to the patient and forgoes the associated time and cost. The time for model generation and sterilisation was < 24 h. RESULTS We describe two patients (3 and 6 years old) requiring occipitocervical instrumented fixation for cervical myelopathy secondary to Morquio syndrome with 3D-SSTGs. In the second case, bilateral laminar screw trajectories were also incorporated into the same guide due to the presence of high-riding vertebral arteries. Registration of the postoperative CT to the pre-operative imaging revealed that screws were optimally placed and accurately followed the predefined trajectory. CONCLUSION To our knowledge, we present the first clinical report of 3D-printed spinal screw trajectory guides at the craniocervical junction in paediatric patients with skeletal dysplasia. The novel combination of multiple trajectories within the same guide provides the intraoperative flexibility of potential bailout options. Future studies will better define the potential of this technology to optimise personalised non-standard screw trajectories.
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Affiliation(s)
- Vejay N Vakharia
- Department of Neurosurgery, Great Ormond Street Hospital, UCL Great Ormond Street Institute of Child Health, London, UK. .,Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
| | - Luke Smith
- Department of Neurosurgery, Great Ormond Street Hospital, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Zubair Tahir
- Department of Neurosurgery, Great Ormond Street Hospital, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Rachel Sparks
- School of Biomedical Engineering and Imaging Sciences, St Thomas' Hospital, King's College London, London, UK
| | - Sebastien Ourselin
- School of Biomedical Engineering and Imaging Sciences, St Thomas' Hospital, King's College London, London, UK
| | - Stewart Tucker
- Department of Neurosurgery, Great Ormond Street Hospital, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Dominic Thompson
- Department of Neurosurgery, Great Ormond Street Hospital, UCL Great Ormond Street Institute of Child Health, London, UK
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Sonone S, Dahapute AA, Waghchoure C, Marathe N, Keny SA, Singh K, Gala R. Anatomic Considerations of Anterior Transarticular Screw Fixation for Atlantoaxial Instability. Asian Spine J 2019; 13:890-894. [PMID: 31309770 PMCID: PMC6894963 DOI: 10.31616/asj.2019.0006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/13/2019] [Indexed: 11/23/2022] Open
Abstract
Study Design Cadaveric, observational study. Purpose Atlantoaxial instability (AAI) is characterized by excessive movement at the C1–C2 junction between the atlas and axis. An anterior surgical approach to expose the upper cervical spine for internal fixation and bone grafting has been developed to fix AAI. Currently, no anatomic information exists on the anterior transarticular atlantoaxial screw or screw and plate fixation between C1 and C2 in the Indian population. The objective of this study is to assess the anatomic landmarks of C1–C2 vertebrae: entry point, trajectory, screw length, and safety of the procedure. Overview of Literature Methods outlined by Magerl and Harms are the optimal approaches among the dorsal techniques. Contraindications for these techniques include aberrant location of vertebral arteries, fractures of C1–C2 posterior structures. In these cases, anterior transarticular fixation is an alternative. Several available screw insertion trajectories have been reported. Biomechanical studies have demonstrated that adequate rigidity of this fixation is comparable with posterior fusion techniques. Methods Direct measurements using Vernier calipers and a goniometer were recorded from 30 embalmed human cadavers. The primary parameters measured were the minimum and maximum lateral and posterior angulations of the screw in the sagittal and coronal planes, respectively, and optimum screw length, if it was placed accurately. Results The posterior and lateral angles of screw placement in the coronal and sagittal planes ranged from 16° to 30° (mean±standard deviation [SD], 23.93°±3.93°) and 8° to 17° (mean±SD, 13.3°±2.26°), respectively. The optimum screw length was 25–38 mm (mean±SD, 28.76±3.69 mm). Conclusions If the screw was inserted without lateral angulation, the spinal canal or cord could be violated. If a longer screw was inserted with greater posterior angulation, the vertebral artery at the posterior or posterolateral aspect of the C1 superior facet could be violated. Thus, 26° and 30° of lateral and posterior angulations, respectively, are the maximum angles permissible to avoid injury of the vertebral artery and violations of the spinal canal or atlanto-occipital joint.
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Affiliation(s)
- Sandeep Sonone
- Department of Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India
| | | | - Chaitanya Waghchoure
- Department of Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India
| | - Nandan Marathe
- Department of Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India
| | - Swapnil Anil Keny
- Department of Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India
| | - Kritarth Singh
- Department of Pharmacology, Seth GS Medical College and KEM Hospital, Mumbai, India
| | - Rohan Gala
- Department of Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India
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Mizutani J, Inoue N, Otsuka Y, Furuya A, Espinoza Orias AA, Otsuka T. Biomechanical and Anatomical Validity of the Short Posterior Arch Screw. Neurospine 2018; 16:347-353. [PMID: 30653910 PMCID: PMC6603827 DOI: 10.14245/ns.1836156.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/31/2018] [Indexed: 01/05/2023] Open
Abstract
Objective This study was conducted to clarify the validity of the short posterior arch screw (S-PAS). The S-PAS is inserted only in the pedicle-analogue portion of the posterior arch. The S-PAS screw length is almost half that conventional C1 lateral mass screws inserted via the posterior arch (via-PAS). S-PAS reduces the risk of vertebral artery injury (VAI) because it never reaches the transverse foramen. Although the biomechanical validity of various C1 lateral mass screws (C1LMS) analyzed in young specimens have been published, that of unicortically inserted C1LMS such as the unicortical Harms screw, S-PAS, and via-PAS for elderly patients is concerning because of the high prevalence of osteoporosis in the elderly.
Methods Nine fresh frozen cadavers (average age at death, 72.1 years) were used for pullout testing. The bone mineral density of each specimen was evaluated using quantitative computed tomography.
Results The pullout strength of via-PAS (1,048.5 N) was significantly greater than that of the unicortical Harms screw (257.9 N) (p<0.05). The pullout strength of S-PAS was 720.3 N, which was also significantly greater than that of the unicortical Harms screw (p<0.05).
Conclusion The via-PAS and S-PAS are valid surgical options, even in elderly patients. Along with sufficient biomechanical strength, the S-PAS screw prevents VAI.
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Affiliation(s)
- Jun Mizutani
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Nozomu Inoue
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Yoshihisa Otsuka
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Aiharu Furuya
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | | | - Takanobu Otsuka
- Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Larsen AMG, Grannan BL, Koffie RM, Coumans JV. Atlantoaxial Fusion Using C1 Sublaminar Cables and C2 Translaminar Screws. Oper Neurosurg (Hagerstown) 2018; 14:647-653. [PMID: 28962019 DOI: 10.1093/ons/opx164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 06/27/2017] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Atlantoaxial instability, which can arise in the setting of trauma, degenerative diseases, and neoplasm, is often managed surgically with C1-C2 arthrodesis. Classical C1-C2 fusion techniques require placement of instrumentation in close proximity to the vertebral artery and C2 nerve root. OBJECTIVE To report a novel C1-C2 fusion technique that utilizes C2 translaminar screws and C1 sublaminar cables to decrease the risk of injury to the vertebral artery and C2 nerve root. METHODS To facilitate fixation to the atlas, while minimizing the risk of injury to the vertebral artery and to the C2 nerve root, we sought to determine the feasibility of using a soft cable around the C1 arch and affixing it to a rod connected to C2 laminar screws. We reviewed our experience in 3 patients. RESULTS We used this technique in patients in whom we anticipated difficult C1 screw placement. Three patients were identified through a review of the senior author's cases. Atlantoaxial instability was associated with trauma in 2 patients and chronic degenerative changes in 1 patient. Common symptoms on presentation included pain and limited range of motion. All patients underwent C1-C2 fusion with C2 translaminar screws with sublaminar cable harnessing of the posterior arch of C1. There were no reports of postoperative complications or hardware failure. CONCLUSION We demonstrate a novel, technically straightforward approach for C1-C2 fusion that minimizes risk to the vertebral artery and to the C2 nerve root, while still allowing for semirigid fixation in instances of both traumatic and chronic degenerative atlantoaxial instability.
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Affiliation(s)
- Alexandra M Giantini Larsen
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts.,Department of Neurosurgery, Harvard Medical School, Boston, Massachusetts
| | - Benjamin L Grannan
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts.,Department of Neurosurgery, Harvard Medical School, Boston, Massachusetts
| | - Robert M Koffie
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts.,Department of Neurosurgery, Harvard Medical School, Boston, Massachusetts
| | - Jean-Valéry Coumans
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts.,Department of Neurosurgery, Harvard Medical School, Boston, Massachusetts
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Advantages of an on-the-screwhead crosslink connector for atlantoaxial fixation using the Goel/Harms technique. J Clin Neurosci 2018; 50:183-189. [DOI: 10.1016/j.jocn.2018.01.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 01/08/2018] [Indexed: 11/20/2022]
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Wu AM, Jin HM, Lin ZK, Chi YL, Wang XY. Percutaneous anterior C1/2 transarticular screw fixation: salvage of failed percutaneous odontoid screw fixation for odontoid fracture. J Orthop Surg Res 2017; 12:141. [PMID: 28962628 PMCID: PMC5622415 DOI: 10.1186/s13018-017-0640-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/17/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The objective of this study is to investigate the outcomes and safety of using percutaneous anterior C1/2 transarticular screw fixation as a salvage technique for odontoid fracture if percutaneous odontoid screw fixation fails. METHODS Fifteen in 108 odontoid fracture patients (planned to be treated by percutaneous anterior odontoid screw fixation) were failed to introduce satisfactory odontoid screw trajectory. To salvage this problem, we chose the percutaneous anterior C1/2 transarticular screw fixation technique in treatment of these patients. The visual analogue score (VAS) of neck pain and Neck Disability Index (NDI) of all patients were scored at pre-operation, 3 months after operation, and final follow-up. Additional, technique-related complications were recorded and collected. RESULTS Percutaneous C1/2 transarticular screw fixation was performed successfully in all 15 patients whose odontoid screw fixation failed. No technique-related complications (such as nerve injury, spinal cord injury, and esophageal injury) occurred. The VAS of neck pain and NDI score improved significantly (P = 0.000) after operation, and no significant differences were found when compared to 93 non-salvage patients who successfully performed the percutaneous anterior odontoid screw fixation. No screw loose or breakage occurred, all of the odontoid fractures achieve radiographic fusion, bony fusion bridge could be observed at the C1/2 lateral articular facet on 9/15 patients. CONCLUSIONS We suggest that percutaneous anterior C1/2 transarticular screw fixation is a good alternative salvage technique if percutaneous odontoid screw fixation failed, and it is a minimally invasive, feasible, and safe technique.
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Affiliation(s)
- Ai-Min Wu
- Department of Spine Surgery, Zhejiang Spine Surgery Center, Orthopaedic Hospital, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109# XueYuan Western Road, Wenzhou, Zhejiang 325027 China
| | - Hai-Ming Jin
- Department of Spine Surgery, Zhejiang Spine Surgery Center, Orthopaedic Hospital, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109# XueYuan Western Road, Wenzhou, Zhejiang 325027 China
| | - Zhong-Ke Lin
- Department of Spine Surgery, Zhejiang Spine Surgery Center, Orthopaedic Hospital, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109# XueYuan Western Road, Wenzhou, Zhejiang 325027 China
| | - Yong-Long Chi
- Department of Spine Surgery, Zhejiang Spine Surgery Center, Orthopaedic Hospital, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109# XueYuan Western Road, Wenzhou, Zhejiang 325027 China
| | - Xiang-Yang Wang
- Department of Spine Surgery, Zhejiang Spine Surgery Center, Orthopaedic Hospital, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109# XueYuan Western Road, Wenzhou, Zhejiang 325027 China
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Bhatia N, Rama A, Sievers B, Quigley R, McGarry MH, Lee YP, Lee TQ. Biomechanical Evaluation of Unilateral Versus Bilateral C1 Lateral Mass-C2 Intralaminar Fixation. Global Spine J 2017; 7:239-245. [PMID: 28660106 PMCID: PMC5476353 DOI: 10.1177/2192568217694152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
STUDY DESIGN Biomechanical, cadaveric study. OBJECTIVES To compare the relative stiffness of unilateral C1 lateral mass-C2 intralaminar fixation to intact specimens and bilateral C1 lateral mass-C2 intralaminar constructs. METHODS The biomechanical integrity of a unilateral C1 lateral mass-C2 intralaminar screw construct was compared to intact specimens and bilateral C1 lateral mass-C2 intralaminar screw constructs. Five human cadaveric specimens were used. Range of motion and stiffness were tested to determine the stiffness of the constructs. RESULTS Unilateral fixation significantly decreased flexion/extension range of motion compared to intact (P < .001) but did not significantly affect axial rotation (P = .3) or bending range of motion (P = .3). There was a significant decrease in stiffness in extension for both unilateral and bilateral fixation techniques compared to intact (P = .04 and P = .03, respectively). There was also a significant decrease in stiffness for ipsilateral rotation for the unilateral construct compared to intact (P = .007) whereas the bilateral construct significantly increased ipsilateral rotation stiffness compared to both intact and unilateral fixation (P < .001). CONCLUSION Bilateral constructs did show improved biomechanical properties compared to the unilateral constructs. However, unilateral C1-C2 fixation using a C1 lateral mass and C2 intralaminar screw-rod construct decreased range of motion and improved stiffness compared to the intact state with the exception of extension and ipsilateral rotation. Hence, a unilateral construct may be acceptable in clinical situations in which bilateral fixation is not possible, but an external orthosis may be necessary to achieve a fusion.
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Affiliation(s)
- Nitin Bhatia
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA
| | - Asheen Rama
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA
| | - Brandon Sievers
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA
| | - Ryan Quigley
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA
| | - Michelle H. McGarry
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA
| | - Yu-Po Lee
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA,Yu-Po Lee, Department of Orthopaedic Surgery, UC Irvine Medical Center, 101 The City Drive South, Pavilion 3, Orange, CA 92868, USA.
| | - Thay Q Lee
- University of California, Irvine, CA, USA,VA Long Beach Healthcare System, Irvine, CA, USA
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Zhang P, Liu Q, Xu T, Sun D, Yang J, Ni B. Biomechanical Study of 3 Atlantoaxial Proactive Vertebral Artery Injury Prevention Fixation Combinations. World Neurosurg 2016; 93:293-8. [PMID: 27345833 DOI: 10.1016/j.wneu.2016.06.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the biomechanical stability of 3 atlantoaxial proactive vertebral artery injury prevention fixation combinations. METHODS We used 6 fresh human cadaveric C0-C4 specimens for the biomechanical test with moment control in 6 loading directions. First, range of motion (ROM) was measured in the intact specimens before they were destabilized; next, ROM of the 4 conditions fixed with 4 different fixation combinations were tested in alternating sequence: bilateral transarticular screw (TAS) and 3 test combinations: C1 laminar hook (C1LH) and C2 intralaminar screw (C2ILS) on 1 side combined with TAS (C1LH-C2ILS/TAS) or C1LH and TAS (C1LH-C2ILS/C1LH-TAS) or C1LH and C2ILS on the other side (C1LH-C2ILS/C1LH-C2ILS). RESULTS ROM of all 4 instrumented sets significantly decreased compared with intact specimens in all the loading cases (flexion, left and right lateral bending, left and right axial rotation) except extension. Compared with the TAS group, all 3 test groups showed higher stiffness in flexion and equivalent stability in the other 5 directions. Side-by-side comparison among the 3 test fixation techniques showed no significant difference. CONCLUSIONS The combination of C1LH and C2ILS supplemented with contralateral TAS or C1LH and TAS or C1LH and C2ILS was superior to bilateral TAS fixation with regard to biomechanics and vertebral artery safety.
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Affiliation(s)
- Peng Zhang
- Department of Orthopedics, The Second Affiliated Hospital, The Second Military Medical University, Shanghai, China
| | - Qi Liu
- Department of Orthopedics, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Tianming Xu
- Department of Orthopedics, The Second Affiliated Hospital, The Second Military Medical University, Shanghai, China
| | - Dezhi Sun
- Department of Orthopedics, The Second Affiliated Hospital, The Second Military Medical University, Shanghai, China
| | - Jun Yang
- Department of Orthopedics, The Second Affiliated Hospital, The Second Military Medical University, Shanghai, China
| | - Bin Ni
- Department of Orthopedics, The Second Affiliated Hospital, The Second Military Medical University, Shanghai, China.
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Xu T, Guo Q, Liu Q, Zhang P, Lu M, Lu X, Chen F, Guo X, Ni B. Biomechanical Evaluation of a Novel Integrated C1 Laminar Hook Combined with C1-C2 Transarticular Screws for Atlantoaxial Fusion: An In Vitro Human Cadaveric Study. World Neurosurg 2016; 92:133-139. [PMID: 27185648 DOI: 10.1016/j.wneu.2016.04.126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/28/2016] [Accepted: 04/30/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To evaluate the acute stability of a novel integrated C1 laminar hook (H) combined with a C1-C2 transarticular screw (TAS) with established techniques. METHODS A novel integrated C1 laminar hook was tested. Seven human cadaveric cervical spines (C0-C3) were used. The range of motion (ROM) of C1-C2 during flexion-extension, lateral bending, and axial rotation were recorded. The specimens were tested under the following conditions: intact, destabilized (using a type II odontoid fracture model), and destabilized but with internal fixation. The following screw systems were used: bilateral C1-C2 TAS combined with the Gallie (G) technique (TAS+G), C1-C2 TAS combined with a novel integrated C1 laminar hook (TAS+H), C1 lateral mass screw and C2 pedicle screws (C2PS+C1LMS), and novel integrated C1 laminar hook combined with C2 pedicle screws (C2PS+H). The TASs were always inserted after the C2PSs. The C2PS+C1LMS and C2PS+H tests were performed alternatively, as were the TAS+G and TAS+H tests. RESULTS All fixation constructs greatly improved acute atlantoaxial stability, with no significant difference among TAS+H, TAS+G, and C2PS+C1LMS (all P > 0.05). C2PS+H showed the greatest C1-C2 ROM in axial rotation, significantly different from TAS+G, C2PS+C1LMS, and TAS+H fixation models (all P < 0.05). However, there were no significant differences between C2PS+H and the other 3 models in flexion-extension and lateral bending (all P > 0.05). CONCLUSIONS The TAS+H technique can achieve acute stability comparable to that with the TAS+G technique for treating C1-C2 instability. The C2PS+H is a promising alternative, although it provides less stability in axial rotation than TAS+G, TAS+H, or C2PS+C1LMS.
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Affiliation(s)
- Tianming Xu
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China; Department of Orthopedics, No. 455 Hospital, The Chinese People's Liberation Army, Shanghai, People's Republic of China
| | - Qunfeng Guo
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Qi Liu
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Peng Zhang
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Ming Lu
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Xuhua Lu
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Fei Chen
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Xiang Guo
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China
| | - Bin Ni
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai, People's Republic of China.
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Wu AM, Wang W, Xu H, Lin ZK, Yang XD, Wang XY, Xu HZ, Chi YL. A novel computed method to reconstruct the bilateral digital interarticular channel of atlas and its use on the anterior upper cervical screw fixation. PeerJ 2016; 4:e1737. [PMID: 26925345 PMCID: PMC4768695 DOI: 10.7717/peerj.1737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 02/03/2016] [Indexed: 11/21/2022] Open
Abstract
Purpose. To investigate a novel computed method to reconstruct the bilateral digital interarticular channel of atlas and its potential use on the anterior upper cervical screw fixation. Methods. We have used the reverse engineering software (image-processing software and computer-aided design software) to create the approximate and optimal digital interarticular channel of atlas for 60 participants. Angles of channels, diameters of inscribed circles, long and short axes of ellipses were measured and recorded, and gender-specific analysis was also performed. Results. The channels provided sufficient space for one or two screws, and the parameters of channels are described. While the channels of females were smaller than that of males, no significant difference of angles between males and females were observed. Conclusion. Our study demonstrates the radiological features of approximate digital interarticular channels, optimal digital interarticular channels of atlas, and provides the reference trajectory of anterior transarticular screws and anterior occiput-to-axis screws. Additionally, we provide a protocol that can help make a pre-operative plan for accurate placement of anterior transarticular screws and anterior occiput-to-axis screws.
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Affiliation(s)
- Ai-Min Wu
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
| | - Wenhai Wang
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
| | - Hui Xu
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
| | - Zhong-Ke Lin
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
| | - Xin-Dong Yang
- Department of Anatomy, Wenzhou Medical University , Wenzhou , China
| | - Xiang-Yang Wang
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
| | - Hua-Zi Xu
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
| | - Yong-Long Chi
- Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province , Wenzhou, Zhejiang , China
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14
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Wu AM, Wang XY, Zhou F, Zhang XL, Xu HZ, Chi YL. Percutaneous atlantoaxial anterior transarticular screw fixation combined with mini-open posterior C1/2 wire fusion for patients with a high-riding vertebral artery. J Spinal Cord Med 2016; 39:234-9. [PMID: 25659962 PMCID: PMC5072504 DOI: 10.1179/2045772314y.0000000298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
CONTEXT/OBJECTIVE To describe the technique and clinical results of percutaneous atlantoaxial anterior transarticular fixation combined with limited exposure posterior C1/2 arthrodesis in patients with a high-riding vertebral artery. DESIGN SETTING Zhejiang Spine Center, China. PARTICIPANTS Five patients with a high-riding vertebral artery and an upper cervical fracture. INTERVENTIONS Percutaneous atlantoaxial anterior transarticular screw fixation combined with limited exposure posterior C1/2 wire fusion. OUTCOME MEASURES Computed tomography scans were used to assess the high-riding vertebral artery and feasibility of anterior transarticular screw fixation preoperatively. A Philadelphia collar was used to immobilize the neck postoperatively. Anteroposterior (open-mouth) and lateral views were obtained at pre/postoperation and at the follow-up. RESULTS The operation was performed successfully on all of the patients, and no intraoperative operation-related complications such as nerve injury, vertebral artery, and soft tissue complications occurred. The mean follow-up period was 33.8 months (range: 24 to 58 months). No screw breakage, loosening, pullout, or cutout was observed. Bone union was achieved in all patients at the last follow-up. CONCLUSIONS Our small case series results suggested that percutaneous anterior transarticular screw fixation combined with mini-open posterior C1/2 wire fusion is a technically minimally invasive, safe, feasible, and useful method to treat patients with a high-riding vertebral artery.
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Affiliation(s)
| | - Xiang-Yang Wang
- Correspondence to: Xiang-Yang Wang, Department of Spinal Surgery, Second Affiliated Hospital of Wenzhou Medical College, Zhejiang Spine Center, 109# XueYuan Western Road, WenZhou, Zhejiang, 325027, People's Republic of China. E-mail:
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Du JY, Aichmair A, Kueper J, Wright T, Lebl DR. Biomechanical analysis of screw constructs for atlantoaxial fixation in cadavers: a systematic review and meta-analysis. J Neurosurg Spine 2015; 22:151-61. [DOI: 10.3171/2014.10.spine13805] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
The unique and complex biomechanics of the atlantoaxial junction make the treatment of C1–2 instability a challenge. Several screw-based constructs have been developed for atlantoaxial fixation. The biomechanical properties of these constructs have been assessed in numerous cadaver studies. The purpose of this study was to systematically review the literature on the biomechanical stability achieved using various C1–2 screw constructs and to perform a meta-analysis of the available data.
METHODS
A systematic search of PubMed through July 1, 2013, was conducted using the following key words and Boolean operators: “atlanto [all fields]” AND “axial [all fields]” OR “C1–C2” AND “biomechanic.” Cadaveric studies on atlantoaxial fixation using screw constructs were included. Data were collected on instability models, fixation techniques, and range of motion (ROM). Forest plots were constructed to summarize the data and compare the biomechanical stability achieved.
RESULTS
Fifteen articles met the inclusion criteria. An average (± SD) of 7.4 ± 1.8 cadaveric specimens were used in each study (range 5–12). The most common injury models were odontoidectomy (53.3%) and cervical ligament transection (26.7%). The most common spinal motion segments potted for motion analysis were occiput–C4 (46.7%) and occiput–C3 (33.3%). Four screw constructs (C1 lateral mass–C2 pedicle screw [C1LM–C2PS], C1–2 transarticular screw [C1–C2TA], C1 lateral mass–C2 translaminar screw [C1LM-C2TL], and C1 lateral mass–C2 pars screw [C1LM–C2 pars]) were assessed for biomechanical stability in axial rotation, flexion/extension, and lateral bending, for a total of 12 analyses. The C1LM–C2TL construct did not achieve significant lateral bending stabilization (p = 0.70). All the other analyses showed significant stabilization (p < 0.001 for each analysis). Significant heterogeneity was found among the reported stabilities achieved in the analyses (p < 0.001; I2 > 80% for all significant analyses). The C1LM–C2 pars construct achieved significantly less axial rotation stability (average ROM 36.27° [95% CI 34.22°–38.33°]) than the 3 other constructs (p < 0.001; C1LM–C2PS average ROM 49.26° [95% CI 47.66°–50.87°], C1–C2TA average ROM 47.63° [95% CI 45.22°–50.04°], and C1LM–C2TL average ROM 53.26° [95% CI 49.91°–56.61°]) and significantly more flexion/extension stability (average ROM 13.45° [95% CI 10.53°–16.37°]) than the 3 other constructs (p < 0.001; C1LM–C2PS average ROM 9.02° [95% CI 8.25°–9.80°], C1–C2TA average ROM 7.39° [95% CI 5.60°–9.17°], and C1LM–C2TL average ROM 7.81° [95% CI 6.93°–8.69°]). The C1–C2TA (average ROM 5.49° [95% CI 3.89°–7.09°]) and C1LM–C2 pars (average ROM 4.21° [95% CI 2.19°–6.24°]) constructs achieved significantly more lateral bending stability than the other constructs (p < 0.001; C1LM–C2PS average ROM 1.51° [95% CI 1.23°–1.78°]; C1LM–C2TL average ROM −0.07° [95% CI −0.44° to 0.29°]).
CONCLUSIONS
Meta-analysis of the existing literature showed that all constructs provided significant stabilization in all axes of rotation, except for the C1LM–C2TL construct in lateral bending. There were significant differences in stabilization achieved in each axis of motion by the various screw constructs. These results underline the various strengths and weaknesses in biomechanical stabilization of different screw constructs. There was significant heterogeneity in the data reported across the studies. Standardized spinal motion segment configuration and injury models may provide more consistent and reliable results.
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16
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Xu R, Bydon M, Macki M, Belkoff SM, Langdale ER, McGovern K, Wolinsky JP, Gokalsan ZL, Bydon A. Biomechanical impact of C2 pedicle screw length in an atlantoaxial fusion construct. Surg Neurol Int 2014; 5:S343-6. [PMID: 25289157 PMCID: PMC4173208 DOI: 10.4103/2152-7806.139664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/30/2014] [Indexed: 11/12/2022] Open
Abstract
Background: Posterior, atlantoaxial (AA) fusions of the cervical spine may include either standard (26 mm) or short (16 mm) C2 pedicle screws. This manuscript focused on an in vitro biomechanical comparison of standard versus short C2 pedicle screws to perform posterior C1-C2 AA fusions. Methods: Twelve human cadaveric spines underwent C1 lateral mass screw and standard C2 pedicle screw (n = 6) versus short C2 pedicle screw (n = 6) fixation. Six additional controls were not instrumented. The peak torque, peak rotational interval, and peak stiffness of the constructs were analyzed to failure levels. Results: The peak torque to construct failure was not statistically significantly different among the control spine (12.2 Nm), short pedicle fixation (15.5 Nm), or the standard pedicle fixation (11.6 Nm), P = 0.79. While the angle at the peak rotation statistically significantly differed between the control specimens (47.7° of relative motion) and the overall instrumented specimens (P < 0.001), the 20.7° of relative rotation in the short C2 pedicle screw specimens was not statistically significantly higher than the 13.7° of relative rotation in the standard C2 pedicle screw specimens (P = 0.39). Similarly, although the average stiffness was statistically significantly lower in control group (0.026 Nm/degree) versus the overall instrumented specimens (P = 0.001), the standard C2 pedicle screws (2.54 Nm/degree) did not differ from the short C2 pedicle screws Conclusions: Both standard and short C2 pedicle screws allow for equally rigid fixation of C1 lateral mass-C2 AA fusions. Usage of a short C2 pedicle screw may be an acceptable method of stabilization in carefully selected patient populations.
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Affiliation(s)
- Risheng Xu
- Johns Hopkins University School of Medicine, Medical Scientist Training Program, Baltimore, Maryland, USA ; Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
| | - Mohamad Bydon
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
| | - Mohamad Macki
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
| | - Stephen M Belkoff
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Evan R Langdale
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kelly McGovern
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
| | - Jean-Paul Wolinsky
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
| | - Ziya L Gokalsan
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
| | - Ali Bydon
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA ; Johns Hopkins Spinal Column Biomechanics and Surgical Outcomes Laboratory, Baltimore, Maryland, USA
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Elgafy H, Pompo F, Vela R, Elsamaloty HM. Ipsilateral arcuate foramen and high-riding vertebral artery: implication on C1-C2 instrumentation. Spine J 2014; 14:1351-5. [PMID: 24509004 DOI: 10.1016/j.spinee.2014.01.054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 12/03/2013] [Accepted: 01/22/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND CONTEXT Several methods for C1-C2 stabilization have been described in the literature. These include C1-C2 transarticular and C1 lateral mass screws. In patients with aberrant anatomy such as a high-riding vertebral artery (VA) or the presence of an arcuate foramen at C1, there exists a higher risk of VA injury. This may lead to excessive bleeding, stroke, and possibly death. There have been several studies determining the incidence of arcuate foramen and high-riding VA occurring individually in the general population, but none have determined their occurrence simultaneously. PURPOSE To determine the prevalence of ponticulus posticus and high-riding VA occurring simultaneously in the general population. STUDY DESIGN Radiological study. METHODS One hundred consecutive computed tomography (CT) scans of the cervical spine were reviewed. Scans that contained an arcuate foramen were identified, and it was indicated whether the foramen was right sided, left sided, or bilateral. In the same group, the thickness of the isthmus and the internal height of the lateral mass of C2 were measured. The VA was considered high riding if the isthmus thickness was less than 5 mm or the isthmus internal height was less than 2 mm. RESULTS Fourteen out of one hundred (14%) patients had a fully formed arcuate foramen. Of these, six were left sided, three were right sided, and five were bilateral. In addition, there were 24 (24%) patients with partially formed ponticulus posticus. Thirty-two (32%) patients were identified to have a high-riding VA. Of these, 13 were left sided, 9 were right sided, and 10 were bilateral. Five (5%) had an ipsilateral arcuate foramen and high-riding VA. CONCLUSIONS The arcuate foramen and high-riding VA are common anomalies that are often not recognized. Although ipsilateral high-riding VA and arcuate foramen rarely occur in the general population, proper identification of these anomalies on preoperative CT scan facilitates planning the safest technique for C1-C2 instrumentation.
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Affiliation(s)
- Hossein Elgafy
- Department of Orthopedic Surgery, University of Toledo Medical Center, 3065 Arlington Ave., Toledo, OH 43614, USA.
| | - Frank Pompo
- Department of Orthopedic Surgery, University of Toledo Medical Center, 3065 Arlington Ave., Toledo, OH 43614, USA
| | - Ryan Vela
- Department of Orthopedic Surgery, University of Toledo Medical Center, 3065 Arlington Ave., Toledo, OH 43614, USA
| | - Haitham M Elsamaloty
- Department of Orthopedic Surgery and Radiology, University of Toledo Medical Center, 3065 Arlington Ave., Toledo, OH 43614, USA
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Fensky F, Kueny RA, Sellenschloh K, Püschel K, Morlock MM, Rueger JM, Lehmann W, Huber G, Hansen-Algenstaedt N. Biomechanical advantage of C1 pedicle screws over C1 lateral mass screws: a cadaveric study. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2014; 23:724-31. [PMID: 24378628 PMCID: PMC3960438 DOI: 10.1007/s00586-013-3143-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 12/14/2013] [Accepted: 12/15/2013] [Indexed: 11/25/2022]
Abstract
PURPOSE The established technique for posterior C1 screw placement is via the lateral mass. Use of C1 monocortical pedicle screws is an emerging technique which utilizes the bone of the posterior arch while avoiding the paravertebral venous plexus and the C2 nerve root. This study compared the relative biomechanical fixation strengths of C1 pedicle screws with C1 lateral mass screws. METHODS Nine human C1 vertebrae were instrumented with one lateral mass screw and one pedicle screw. The specimens were subjected to sinusoidal, cyclic (0.5 Hz) fatigue loading. Peak compressive and tensile forces started from ±25 N and constantly increased by 0.05 N every cycle. Testing was stopped at 5 mm displacement. Cycles to failure, displacement, and initial and end stiffness were measured. Finally, CT scans were taken and the removal torque measured. RESULTS The pedicle screw technique consistently and significantly outperformed the lateral mass technique in cycles to failure (1,083 ± 166 vs. 689 ± 240 cycles), initial stiffness (24.6 ± 3.9 vs. 19.9 ± 3.2 N/mm), end stiffness (16.6 ± 2.7 vs. 11.6 ± 3.6 N/mm) and removal torque (0.70 ± 0.78 vs. 0.13 ± 0.09 N m). Only 33 % of pedicle screws were loose after testing compared to 100 % of lateral mass screws. CONCLUSIONS C1 pedicle screws were able to withstand higher toggle forces than lateral mass screws while maintaining a higher stiffness throughout and after testing. From a biomechanical point of view, the clinical use of pedicle screws in C1 is a promising alternative to lateral mass screws.
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Affiliation(s)
- Florian Fensky
- Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany,
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Solanki GA, Martin KW, Theroux MC, Lampe C, White KK, Shediac R, Lampe CG, Beck M, Mackenzie WG, Hendriksz CJ, Harmatz PR. Spinal involvement in mucopolysaccharidosis IVA (Morquio-Brailsford or Morquio A syndrome): presentation, diagnosis and management. J Inherit Metab Dis 2013; 36:339-55. [PMID: 23385297 PMCID: PMC3590412 DOI: 10.1007/s10545-013-9586-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/29/2012] [Accepted: 01/07/2013] [Indexed: 11/30/2022]
Abstract
Mucopolysaccharidosis IVA (MPS IVA), also known as Morquio-Brailsford or Morquio A syndrome, is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase (GALNS). MPS IVA is multisystemic but manifests primarily as a progressive skeletal dysplasia. Spinal involvement is a major cause of morbidity and mortality in MPS IVA. Early diagnosis and timely treatment of problems involving the spine are critical in preventing or arresting neurological deterioration and loss of function. This review details the spinal manifestations of MPS IVA and describes the tools used to diagnose and monitor spinal involvement. The relative utility of radiography, computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of cervical spine instability, stenosis, and cord compression is discussed. Surgical interventions, anaesthetic considerations, and the use of neurophysiological monitoring during procedures performed under general anaesthesia are reviewed. Recommendations for regular radiological imaging and neurologic assessments are presented, and the need for a more standardized approach for evaluating and managing spinal involvement in MPS IVA is addressed.
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Affiliation(s)
- Guirish A Solanki
- Department of Paediatric Neurosurgery, Birmingham Children's Hospital NHS Foundation Trust, Steelhouse Lane, Birmingham, UK.
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Elliott RE, Tanweer O, Boah A, Morsi A, Ma T, Frempong-Boadu A, Smith ML. Is external cervical orthotic bracing necessary after posterior atlantoaxial fusion with modern instrumentation: meta-analysis and review of literature. World Neurosurg 2012; 79:369-74.e1-12. [PMID: 22484066 DOI: 10.1016/j.wneu.2012.03.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 12/10/2011] [Accepted: 03/29/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND No guidelines exist regarding external cervical orthoses (ECO) after atlantoaxial fusion. We reviewed published series describing C1-2 posterior instrumented fusions with screw-rod constructs (SRC) or transarticular screws (TAS) and compared rates of fusion with and without postoperative ECO. METHODS Online databases were searched for English-language articles between 1986 and April 2011 describing ECO use after posterior atlantoaxial instrumentation with SRC or TAS. Eighteen studies describing 947 patients who had SRC (± ECO: 254 of 693 patients), and 33 studies describing 1424 patients with TAS (± ECO: 525 of 899 patients) met inclusion criteria. Meta-analysis techniques were applied to estimate rates of fusion with and without ECO use. RESULTS All studies provided class III evidence, and no studies directly compared outcomes with or without ECO use. There was no significant difference in the proportion of patients who achieved successful fusion between patients treated with ECO and without ECO for SRC or TAS patients. Point estimates and 95% confidence intervals (CI) for rates of fusion ± ECO were 97.4% (CI: 95.2% to 98.6%) versus 97.9% (CI: 93.6% to 99.3%) for SRC and 93.6% (CI: 90.7% to 95.6%) versus 95.3% (CI: 90.8% to 97.7%) for TAS. There was no correlation between duration of ECO treatment and fusion (dose effect). CONCLUSIONS After C1-2 fusion with modern instrumentation, ECO may be unnecessary (class III). Some centers recommend ECO use with patients with softer bone quality (class IV). Prospective, randomized studies with validated radiographic and clinical outcome metrics are necessary to determine the utility of ECO after C1-2 fusion and its impact on patient comfort and cost.
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