scholarly journals Posterior atlantoaxial stabilization: new alternative to C1–2 transarticular screws

2002 ◽  
Vol 12 (1) ◽  
pp. 1-5 ◽  
Author(s):  
John K. Stokes ◽  
Alan T. Villavicencio ◽  
Paul C. Liu ◽  
Robert S. Bray ◽  
J. Patrick Johnson
Keyword(s):  
Nerve Root ◽  
Pedicle Screws ◽  
Atlantoaxial Instability ◽  
Atlantoaxial Joint ◽  
Lateral Mass ◽  
Success Rates ◽  
Fixation Procedure ◽  
Transarticular Screw ◽  
Precise Knowledge ◽  
Flexion Extension

Object Surgical treatment of atlantoaxial instability has evolved to include various posterior wiring techniques including Brooks, Gallie, and Sonntag fusions in which success rates range from 60 to 100%. The Magerl–Seemans technique in which C1–2 transarticular screws are placed results in fusion rates between 87 and 100%. This procedure is technically demanding and requires precise knowledge of the course of the vertebral arteries (VAs). The authors introduce a new C1–2 fixation procedure in which C-1 lateral mass and C-2 pedicle screws are placed that may have advantages over C1–2 transarticular screw constructs. Methods A standard posterior C1–2 exposure is obtained. Polyaxial C-2 pedicle screws and C-1 lateral mass screws are placed bilaterally. Rods are connected to the screws and secured using locking nuts. A cross-link is then placed. Fusion can be performed at the atlantoaxial joint by elevating the C-2 nerve root. The technique for this procedure has been used in four cases of atlantoaxial instability at the author's institution. There have been no C-2 nerve root– or VA-related injuries. No cases of construct failure have been observed in the short-term follow up period. Conclusions Atlantoaxial lateral mass and axial pedicle screw fixation offers an alternative means of achieving atlantoaxial fusion. The technique is less demanding than that required for transarticular screw placement and may avoid the potential complication of VA injury. The cross-linked construct is theoretically stable in flexion, extension, and rotation. Laminectomy or fracture of the posterior elements does not preclude use of this fixation procedure.

scholarly journals Transoral digital reduction of complete anterior odontoid dislocation followed by fiducial-based navigated transcondylar screw fixation: illustrative case

2022 ◽  
Vol 3 (3) ◽  
Keyword(s):  
Spinal Fusion ◽  
Screw Fixation ◽  
Treatment Options ◽  
Pedicle Screws ◽  
Craniocervical Junction ◽  
Atlantoaxial Instability ◽  
Illustrative Case ◽  
Trauma Patients ◽  
Lateral Mass ◽  
Craniocervical Instability

BACKGROUND Posterior atlantoaxial dislocations (i.e., complete anterior odontoid dislocation) without C1 arch fractures are a rare hyperextension injury most often found in high-velocity trauma patients. Treatment options include either closed or open reduction and optional spinal fusion to address atlantoaxial instability due to ligamentous injury. OBSERVATIONS A 60-year-old male was struck while on his bicycle by a truck and sustained an odontoid dislocation without C1 arch fracture. Imaging findings additionally delineated a high suspicion for craniocervical instability. The patient had neurological issues due to both a head injury and ischemia secondary to an injured vertebral artery. He was stabilized and transferred to our facility for definitive neurosurgical care. LESSONS The patient underwent a successful transoral digital closed reduction and posterior occipital spinal fusion via a fiducial-based transcondylar, C1 lateral mass, C2 pedicle, and C3 lateral mass construct. This unique reduction technique has not been recorded in the literature before and avoided potential complications of overdistraction and the need for odontoidectomy. Furthermore, the use of bone fiducials for navigated screw fixation at the craniocervical junction is a novel technique and recommended particularly for placement of technically demanding transcondylar screws and C2 pedicle screws where pars anatomy is potentially unfavorable.

Biomechanical comparison of anterior and posterior stabilization methods in atlantoaxial instability

2004 ◽  
Vol 100 (3) ◽  
pp. 277-283 ◽  
Author(s):  
Sung-Min Kim ◽  
T. Jesse Lim ◽  
Josemaria Paterno ◽  
Tae-Jin Hwang ◽  
Kun-Woo Lee ◽  
...  
Keyword(s):  
The Other ◽  
Atlantoaxial Instability ◽  
Fixation Method ◽  
Posterior Fixation ◽  
Lateral Bending ◽  
Biomechanical Stability ◽  
Transarticular Screw ◽  
Content Type ◽  
Flexion Extension ◽  
Fine Print

Object. The authors compared the biomechanical stability of two anterior fixation procedures—anterior C1–2 Harms plate/screw (AHPS) fixation and the anterior C1–2 transarticular screw (ATS) fixation; and two posterior fixation procedures—the posterior C-1 lateral mass combined with C-2 pedicle screw/rod (PLM/APSR) fixation and the posterior C1–2 transarticular screw (PTS) fixation after destabilization. Methods. Sixteen human cervical spine specimens (Oc—C3) were tested in three-dimensional flexion—extension, axial rotation, and lateral bending motions after destabilization by using an atlantoaxial C1–2 instability model. In each loading mode, moments were applied to a maximum of 1.5 Nm, and the range of motion (ROM), neutral zone (NZ), and elastic zone (EZ) were determined and values compared using the intact spine, the destabilized spine, and the postfixation spine. The AHPS method produced inferior biomechanical results in flexion—extension and lateral bending modes compared with the intact spine. The lateral bending NZ and ROM for this method differed significantly from the other three fixation techniques (p < 0.05), although statistically significant differences were not obtained for all other values of ROM and NZ for the other three procedures. The remaining three methods restored biomechanical stability and improved it over that of the intact spine. Conclusions. The PLM/APSR fixation method was found to have the highest biomechanical stiffness followed by PTS, ATS, and AHPS fixation. The PLM/APSR fixation and AATS methods can be considered good procedures for stabilizing the atlantoaxial joints, although specific fixation methods are determined by the proper clinical and radiological characteristics in each patient.

scholarly journals Biomechanical Comparison of Posterior Fixation Combinations with an Allograft Spacer between the Lateral Mass and Pedicle Screws

2020 ◽  
Vol 10 (20) ◽  
pp. 7291
Author(s):  
Soo-Bin Lee ◽  
Hwan-Mo Lee ◽  
Tae-Hyun Park ◽  
Sung Lee ◽  
Young-Woo Kwon ◽  
...  
Keyword(s):  
Pedicle Screws ◽  
Element Model ◽  
Axial Rotation ◽  
Posterior Fixation ◽  
Hybrid Technique ◽  
Lateral Mass ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Hybrid Motion ◽  
Biomechanical Comparison

Background: There are a few biomechanical studies that describe posterior fixation methods with pedicle screws (PS) and lateral mass screws (LMS); the combination of both screw types and their effect on an allograft spacer in a surgically treated cervical segment is unknown. Methods: Finite element model (FEM) analyses were used to investigate the effects of a hybrid technique using posterior PS and LMS. Stress distribution and subsidence risk from a combination of screws under hybrid motion control conditions, including flexion, extension, axial rotation, and lateral bending, were investigated to evaluate the biomechanical characteristics of different six-screw combinations. Findings: The load sharing on the allograft spacer in flexion mode was highest in the LMS model (74.6%) and lowest in the PS model (35.1%). The likelihood of subsidence of allograft spacer on C6 was highest in the screws from the distal LMS (type 5) model during flexion and extension (4.902 MPa, 30.1% and 2.189 MPa, 13.4%). In lateral bending, the left unilateral LMS (type 4) model screws on C5 (3.726 MPa, 22.9%) and C6 (2.994 MPa, 18.4%) yielded the greatest subsidence risks, because the lateral bending forces were supported by the LMS. In counterclockwise axial rotation, the left unilateral LMS (type 4) model screws on C5 (3.092 MPa, 19.0%) and C6 (3.076 MPa, 18.9%) demonstrated the highest subsidence risks. Conclusion: The asymmetrical ipsilateral use of LMS and posterior PS in lateral bending and axial rotation demonstrated the lowest stability and greatest subsidence risk. We recommend bilateral symmetrical insertion of LMS or posterior PS and posterior PS on distal vertebrae for increased stability and reduced risk of allograft spacer subsidence.

Placement of C1 Lateral Mass Screw—Alternative Technique: 2-Dimensional Operative Video

2020 ◽  
Vol 19 (3) ◽  
pp. E297-E297 ◽  
Author(s):  
R Tushar Jha ◽  
Nicholas Dietz ◽  
Ehsan Dowlati ◽  
Faheem Sandhu
Keyword(s):  
Neck Pain ◽  
Atlantoaxial Instability ◽  
Alternative Technique ◽  
Lateral Mass ◽  
Lateral Mass Screw ◽  
Fusion Construct ◽  
Flexion Extension ◽  
The Rich ◽  
Posterior Instrumented Fusion ◽  
C1 Lateral Mass Screw

Abstract This operative video demonstrates a C1 lateral mass instrumentation technique that is an alternative to the traditional Goel and Harms techniques.1,2 The advantages of the alternative technique include minimized blood loss from the rich venous plexus surrounding the C2 dorsal root ganglia (DRG), avoidance and preservation of the C2 DRG, and placement of a robust fully threaded screw without risking neuralgia. These are discussed in detail and presented through a case of atlantoaxial instability. Patient's consent was obtained for creating this surgical video. The patient is a 50-yr-old woman with a 17-yr history of rheumatoid arthritis. She presented with 1 yr of neck pain that failed conservative measures. Flexion-extension radiographs demonstrated an atlantodental index (ADI) that reduced from 7 mm on flexion to 0 mm on extension. The patient underwent a C1-C2 posterior instrumented fusion using the alternative technique of C1 lateral mass instrumentation.2 The steps of this technique are explained in great detail through a microsurgical video. The patient's postoperative course was uneventful. Postoperative radiographs and computed tomography (CT) scan demonstrated reduction of ADI and well-placed instrumentation and fusion construct. Her neck pain was completely resolved by 3 mo following surgical stabilization. In the senior author's experience with placing over 120 C1 lateral mass screws with this alternative technique, there have been no instances of vascular injury, sacrifice of C2 DRG, or instrumentation failure. The alternative technique for placement of C1 lateral mass screw is safe, efficient, and holds certain advantages in comparison to the traditionally described method.  Images within the video have been reproduced from AOSpine section of the AO Surgery Reference, www.aosurgery.org, with permission from AO Surgery. Copyright by AOSpine International, Switzerland; and reprinted from World Neurosurgery, 78(1-2), Kang MM et al, C2 Nerve Root Sectioning in Posterior C1-2 Instrumented Fusions, 170-177, Copyright 2012, with permission from Elsevier.

scholarly journals 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

2016 ◽  
Vol 24 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Jin Guo-Xin ◽  
Wang Huan
Keyword(s):  
Biomechanical Testing ◽  
Pedicle Screws ◽  
Atlantoaxial Instability ◽  
Posterior Arch ◽  
Lateral Bending ◽  
Significant Difference ◽  
Flexion Extension ◽  
Intact Condition ◽  
Atlantoaxial Fixation ◽  
Group B

OBJECT Atlantoaxial instability often requires surgery, and the current methods for fixation pose some risk to vascular and neurological tissues. Thus, new effective and safer methods are needed for salvage operations. This study sought to assess unilateral C-1 posterior arch screws (PASs) and C-2 laminar screws (LSs) combined with 1-side C1–2 pedicle screws (PSs) for posterior C1–2 fixation using biomechanical testing with bilateral C1–2 PSs in a cadaveric model. METHODS Six fresh ligamentous human cervical spines were evaluated for their biomechanics. The cadaveric specimens were tested in their intact condition, stabilization after injury, and after injury at 1.5 Nm of pure moment in 6 directions. The 3 groups tested were bilateral C1–2 PSs (Group A); left side C1–2 PSs with an ipsilateral C-1 PAS + C-2 laminar screw (Group B); and left side C1–2 PSs with a contralateral C-1 PAS + C-2 LS (Group C). During the testing, angular motion was measured using a motion capture platform. Data were recorded, and statistical analyses were performed. RESULTS Biomechanical testing showed that there was no significant difference among the stabilities of these fixation systems in flexion-extension and rotation control. In left lateral bending, the bilateral C1–2 PS group decreased flexibility by 71.9% compared with the intact condition, the unilateral C1–2 PS and ipsilateral PAS+LS group decreased flexibility by 77.6%, and the unilateral C1–2 PS and contralateral PAS+LS group by 70.0%. Each method significantly decreased C1–2 movements in right lateral bending compared with the intact condition, and the bilateral C1–2 PS system was more stable than the C1–2 PS and contralateral PAS+LS system (p = 0.036). CONCLUSIONS A unilateral C-1 PAS + C-2 LS combined with 1-side C-1 PSs provided the same acute stability as the PS, and no statistically significant difference in acute stability was found between the 2 screw techniques. These methods may constitute an alternative method for posterior atlantoaxial fixation.

scholarly journals Cervical pedicle screws fixation treatment the atlantoaxial instability of axis burst fractures

2020 ◽  
Author(s):  
Denglu Yan ◽  
Zaiheng Zhang ◽  
Zhi Zhang
Keyword(s):  
Clinical Outcomes ◽  
Pedicle Screws ◽  
Atlantoaxial Instability ◽  
Burst Fractures ◽  
Significant Difference ◽  
Flexion Extension ◽  
Fixation Treatment ◽  
Cervical Pedicle ◽  
Cervical Pedicle Screws

Abstract BackgroundAlthough the cervical pedicle screws and rods were used for atlantoaxial instable, the axis fractures still a challenge for spine surgeon.ObjectiveThis study was to evaluated the clinical outcomes of axis burst fractures had C1C3 pedicles screws fixation treatment.MethodsFrom June 2014 to July 2018, 45 patients with axis fractures were enrolled in this study; 23 patients was odontoid underwent C1C2 pedicles screws fixation, and 21 patients was odontoid combine body fractures had C1C3 pedicles screws fixation. The clinical outcomes of pain relief (visual analog scale, VAS), functional disability (neck disability index, NDI) were recorded at baseline and at the final follow-up.ResultsThe pain index and NDI were all significantly improved when compared to pretreatment (P < 0.01). The VAS and ND were no significant difference between two groups (P > 0.05). All patients, suffered from severe mechanical upper cervical neck pain at pre-operative, were pain free post-operation. Pre-operative neurological examination was normal in all patients, and remained the same after surgery. All cases showed normal neurological function at the final follow-up. No vascular or neurological complication was noted. The fracture healing and the bony union of the fixed segments were revealed in all cases on CT views. Implant failure and instability were not seen on lateral flexion/extension radiographs of the cervical spine.ConclusionsCervical pedicle screws fixation was effective and safe procedures in the treatment of traumatic spondylolisthesis of axial fractures. The atlantoaxial instable of axis burst fractures can be managed with C1-C3 pedicles screws fixation.

scholarly journals Comparison of two techniques for the treatment for atlantoaxial instability injury: C1–C2 transarticular screws and C1 lateral mass–C2 pedicle screws

2020 ◽  
Author(s):  
Hoang Gia Du ◽  
Dao Xuan Thanh ◽  
Vu Xuan Phuoc ◽  
Nguyen Duc Hoang ◽  
Le Dang Tan ◽  
...  
Keyword(s):  
Blood Loss ◽  
Screw Fixation ◽  
Pedicle Screws ◽  
Operation Time ◽  
Hospital Length ◽  
Pedicle Screw Fixation ◽  
Atlantoaxial Instability ◽  
Lateral Mass ◽  
Fixation Techniques ◽  
Group 2

Abstract Background: The aim was to evaluate the effectiveness and safety of transarticular C1–C2 screw fixation (C1C2-TAS) and C1 lateral mass–C2 pedicle screw fixation (C1LM-C2PS) in patients with C1–C2 instability injuries.Methods: This study was a prospective, self-controlled, single-institute study on two fixation techniques for the treatment of atlantoaxial instability caused by injury. From 06/2006 to 02/2017, 118 patients were allocated into two groups: group 1 (C1C2-TAS group) with 52 patients and group 2 (C1LM-C2PS group) with 66 patients. The investigated variables were noted before, during and after surgery. All patients were closely followed up through physical examination and radiological imaging at 3 months postoperatively.Results: There were significant differences in operation time, blood loss, and hospital length-stay between the two groups (p <0.001). Compared with those in the C1LM-C2PS group, the mean operation time was shorter (78.94 vs. 110.91 min; p = 0.0003), blood loss during surgery was lower (122.31 vs. 258.33 ml; p <0.0001) and hospital length-stay was shorter (5.31 vs. 8.34 days; p = 0.0003) in the C1C2–TAS group. The complication of surgery was low with no injury of vertebral artery. After surgery, clinical presentations were significantly reduced and were statistically significant in both groups. The remaining patients showed satisfactory internal fixation in the postoperative radiographs and CT examination.Conclusion: C1C2-TAS and C1LM-C2PS demonstrated effectiveness and safety in the treatment of patients with atlantoaxial instability injury. Notably, C1C2-TAS resulted in shorter surgical time, lower blood loss during surgery and shorter in-hospital stay than C1LM-C2PS.

Stabilization of the atlantoaxial complex via C-1 lateral mass and C-2 pedicle screw fixation in a multicenter clinical experience in 102 patients: modification of the Harms and Goel techniques

2008 ◽  
Vol 8 (3) ◽  
pp. 222-229 ◽  
Author(s):  
Henry E. Aryan ◽  
C. Benjamin Newman ◽  
Eric W. Nottmeier ◽  
Frank L. Acosta ◽  
Vincent Y. Wang ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Case Series ◽  
Pedicle Screws ◽  
Joint Space ◽  
Atlantoaxial Instability ◽  
Lateral Mass ◽  
X Ray ◽  
Harms Technique ◽  
Flexion And Extension

Object Stabilization of the atlantoaxial complex has proven to be very challenging. Because of the high mobility of the C1–2 motion segment, fusion rates at this level have been substantially lower than those at the subaxial spine. The set of potential surgical interventions is limited by the anatomy of this region. In 2001 Jürgen Harms described a novel technique for individual fixation of the C-1 lateral mass and the C-2 pedicle by using polyaxial screws and rods. This method has been shown to confer excellent stability in biomechanical studies. Cadaveric and radiographic analyses have indicated that it is safe with respect to osseous and vascular anatomy. Clinical outcome studies and fusion rates have been limited to small case series thus far. The authors reviewed the multicenter experience with 102 patients undergoing C1–2 fusion via the polyaxial screw/rod technique. They also describe a modification to the Harms technique. Methods One hundred two patients (60 female and 42 male) with an average age of 62 years were included in this analysis. The average follow-up was 16.4 months. Indications for surgery were instability at the C1–2 level, and a chronic Type II odontoid fracture was the most frequent underlying cause. All patients had evidence of instability on flexion and extension studies. All underwent posterior C-1 lateral mass to C-2 pedicle or pars screw fixation, according to the method of Harms. Thirty-nine patients also underwent distraction and placement of an allograft spacer into the C1–2 joint, the authors' modification of the Harms technique. None of the patients had supplemental sublaminar wiring. Results All but 2 patients with at least a 12-month follow-up had radiographic evidence of fusion or lack of motion on flexion and extension films. All patients with an allograft spacer demonstrated bridging bone across the joint space on plain x-ray films and computed tomography. The C-2 root was sacrificed bilaterally in all patients. A postoperative wound infection developed in 4 patients and was treated conservatively with antibiotics and local wound care. One patient required surgical debridement of the wound. No patient suffered a neurological injury. Unfavorable anatomy precluded the use of C-2 pedicle screws in 23 patients, and thus, they underwent placement of pars screws instead. Conclusions Fusion of C1–2 according to the Harms technique is a safe and effective treatment modality. It is suitable for a wide variety of fracture patterns, congenital abnormalities, or other causes of atlantoaxial instability. Modification of the Harms technique with distraction and placement of an allograft spacer in the joint space may restore C1–2 height and enhance radiographic detection of fusion by demonstrating a graft–bone interface on plain x-ray films, which is easier to visualize than the C1–2 joint.

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