Biomechanical analysis of a novel hook-screw technique for C1–2 stabilization

2012 ◽  
Vol 17 (3) ◽  
pp. 220-226 ◽  
Author(s):  
Marco Túlio Reis ◽  
Eric W. Nottmeier ◽  
Phillip M. Reyes ◽  
Seungwon Baek ◽  
Neil R. Crawford
Keyword(s):  
Range Of Motion ◽  
Medical Devices ◽  
Spatial Relationship ◽  
Pedicle Screws ◽  
Biomechanical Analysis ◽  
Lateral Mass ◽  
Lateral Mass Screws ◽  
Laminar Hooks ◽  
Harms Technique

The Food and Drug Administration has not cleared the following medical devices for the use described in this study. The following medical devices are being discussed for an off-label use: cervical lateral mass screws. Object As an alternative for cases in which the anatomy and spatial relationship between C-2 and a vertebral artery precludes insertion of C-2 pedicle/pars or C1–2 transarticular screws, a technique that includes opposing laminar hooks (claw) at C-2 combined with C-1 lateral mass screws may be used. The biomechanical stability of this alternate technique was compared with that of a standard screw-rod technique in vitro. Methods Flexibility tests were performed in 7 specimens (occiput to C-3) in the following 6 different conditions: 1) intact; 2) after creating instability and attaching a posterior cable/graft at C1–2; 3) after removing the graft and attaching a construct comprising C-1 lateral mass screws and C-2 laminar claws; 4) after reattaching the posterior cable-graft at C1–2 (posterior hardware still in place); 5) after removing the posterior cable-graft and laminar hooks and placing C-2 pedicle screws interconnected to C-1 lateral mass screws via rod; and 6) after reattaching the posterior cable-graft at C1–2 (screw-rod construct still in place). Results All types of stabilization significantly reduced the range of motion, lax zone, and stiff zone compared with the intact condition. There was no significant biomechanical difference in terms of range of motion or lax zone between the screw-rod construct and the screw-claw-rod construct in any direction of loading. Conclusions The screw-claw-rod technique restricts motion much like the standard Harms technique, making it an acceptable alternative technique when aberrant arterial anatomy precludes the placement of C-2 pars/pedicle screws or C1–2 transarticular screws.

Pedicle Screws Can be 4 Times Stronger Than Lateral Mass Screws for Insertion in the Midcervical Spine

2014 ◽  
Vol 27 (2) ◽  
pp. 80-85 ◽  
Author(s):  
Zenya Ito ◽  
Kosaku Higashino ◽  
Satoshi Kato ◽  
Sung Soo Kim ◽  
Eugene Wong ◽  
...  
Keyword(s):  
Pedicle Screws ◽  
Lateral Mass ◽  
Lateral Mass Screws

scholarly journals The use of intraoperative navigation for complex upper cervical spine surgery

2014 ◽  
Vol 36 (3) ◽  
pp. E5 ◽  
Author(s):  
Kern H. Guppy ◽  
Indro Chakrabarti ◽  
Amit Banerjee
Keyword(s):  
Cervical Spine ◽  
Navigation System ◽  
Surgical Navigation ◽  
Spinal Instrumentation ◽  
Pedicle Screws ◽  
Upper Cervical Spine ◽  
Cervical Canal ◽  
Lateral Mass ◽  
Upper Cervical ◽  
Lateral Mass Screws

Imaging guidance using intraoperative CT (O-arm surgical imaging system) combined with a navigation system has been shown to increase accuracy in the placement of spinal instrumentation. The authors describe 4 complex upper cervical spine cases in which the O-arm combined with the StealthStation surgical navigation system was used to accurately place occipital screws, C-1 screws anteriorly and posteriorly, C-2 lateral mass screws, and pedicle screws in C-6. This combination was also used to navigate through complex bony anatomy altered by tumor growth and bony overgrowth. The 4 cases presented are: 1) a developmental deformity case in which the C-1 lateral mass was in the center of the cervical canal causing cord compression; 2) a case of odontoid compression of the spinal cord requiring an odontoidectomy in a patient with cerebral palsy; 3) a case of an en bloc resection of a C2–3 chordoma with instrumentation from the occiput to C-6 and placement of C-1 lateral mass screws anteriorly and posteriorly; and 4) a case of repeat surgery for a non-union at C1–2 with distortion of the anatomy and overgrowth of the bony structure at C-2.

scholarly journals Posterior spinal fusion using a unilateral C1 posterior arch screw and a C2 laminar screw for atlantoaxial fracture dislocation

2019 ◽  
Vol 7 ◽  
pp. 2050313X1984927 ◽  
Author(s):  
Yuichi Ono ◽  
Naohisa Miyakoshi ◽  
Michio Hongo ◽  
Yuji Kasukawa ◽  
Yoshinori Ishikawa ◽  
...  
Keyword(s):  
Pedicle Screws ◽  
Fracture Site ◽  
Fracture Dislocation ◽  
Posterior Arch ◽  
Lateral Mass ◽  
Laminar Screw ◽  
Upper Cervical ◽  
Lateral Mass Screws ◽  
The Right ◽  
C2 Laminar Screw

Introduction: C1 lateral mass screws and C2 pedicle screws are usually chosen to fix atlantoaxial (C1–C2) instability. However, there are a few situations in which these screws are difficult to use, such as in a case with a fracture line at the screw insertion point and bleeding from the fracture site. A new technique using a unilateral C1 posterior arch screw and a C2 laminar screw combined with a contralateral C1 lateral mass screws–C2 pedicle screws procedure for upper cervical fixation is reported. Case Report: A 24-year-old woman had an irreducible C1–C2 anterior dislocation with a type III odontoid fracture on the right side due to a traffic accident. The patient underwent open reduction and posterior C1–C2 fixation. On the left side, a C1 lateral mass screws and a C2 pedicle screws were placed. Because there was bleeding from the fracture site and a high-riding vertebral artery was seen on the right side, a C1 posterior arch screw and a C2 laminar screw were chosen. Eight months after the surgery, computed tomography scans showed healing of the odontoid fracture with anatomically correct alignment. Conclusions: Although there have been few comparable studies, fixation with unilateral C1 posterior arch screw–C2 laminar screw could be a beneficial choice for surgeries involving the upper cervical region in patients with fracture dislocation or arterial abnormalities.

Biomechanical analysis of Goel technique for C1–2 fusion

2011 ◽  
Vol 14 (5) ◽  
pp. 639-646 ◽  
Author(s):  
Jon Park ◽  
Justin K. Scheer ◽  
T. Jesse Lim ◽  
Vedat Deviren ◽  
Christopher P. Ames
Keyword(s):  
Motion Tracking ◽  
Tracking System ◽  
Testing Machine ◽  
Pedicle Screws ◽  
Axial Rotation ◽  
Biomechanical Analysis ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Rod System ◽  
Harms Technique

Object The Goel technique, in which C1–2 intraarticular spacers are used, may be performed to restore stability to a disrupted atlantoaxial complex in conjunction with the Harms technique of placing polyaxial screws and bilateral rods. However, it has yet to be determined biomechanically whether the addition of the C1–2 joint spacers increases the multiaxial rigidity of the fixation construct. The goal of this study was to quantify changes in multiaxial rigidity of the combined Goel-Harms technique with the addition of C1–2 intraarticular spacers. Methods Seven cadaveric cervical spines (occiput–C2) were submitted to nondestructive flexion-extension, lateral bending, and axial rotation tests in a material testing machine spine tester. The authors applied 1.5 Nm at a rate of 0.1 Nm/second and held it constant for 10 seconds. The specimens were loaded 3 times, and data were collected on the third cycle. Testing of the specimens was performed for the following groups: 1) intact (I); 2) with the addition of C-1 lateral mass/C-2 pedicle screws and rod system (I+SR); 3) with C1–2 joint capsule incision, decortication (2 mm on top and bottom of each joint [that is, the C-1 and C-2 surface) and addition of bilateral C1–2 intraarticular spacers at C1–2 junction to the screws and rods (I+SR+C); 4) after removal of the posterior rods and only the bilateral spacers in place (I+C); 5) after removal of spacers and further destabilization with simulated odontoidectomy for a completely destabilized case (D); 6) with addition of posterior rods to the destabilized case (D+SR); and 7) with addition of bilateral C1–2 intraarticular spacers at C1–2 junction to the destabilized case (D+SR+C). The motion of C-1 was measured by a 3D motion tracking system and the motion of C-2 was measured by the rotational sensor of the testing system. The range of motion (ROM) and neutral zone (NZ) across C-1 and C-2 were evaluated. Results For the intact spine test groups, the addition of screws/rods (I+SR) and screws/rods/cages (I+SR+C) significantly reduced ROM and NZ compared with the intact spine (I) for flexion-extension and axial rotation (p < 0.05) but not lateral bending (p > 0.05). The 2 groups were not significantly different from each other in any bending mode for ROM and NZ, but in the destabilized condition the addition of screws/rods (D+SR) and screws/rods/cages (D+SR+C) significantly reduced ROM and NZ compared with the destabilized spine (D) in all bending modes (p < 0.05). Furthermore, the addition of the C1–2 intraarticular spacers (D+SR+C) significantly reduced ROM (flexion-extension and axial rotation) and NZ (lateral bending) compared with the screws and rods alone (D+SR). Conclusions Study result indicated that both the Goel and Harms techniques alone and with the addition of the C1–2 intraarticular spacers to the Goel-Harms technique are advantageous for stabilizing the atlantoaxial segment. The Goel technique combined with placement of a screw/rod construct appears to result in additional construct rigidity beyond the screw/rod technique and appears to be more useful in very unstable cases.

C1 Pedicle Screws Versus C1 Lateral Mass Screws

Spine ◽  
2009 ◽  
Vol 34 (4) ◽  
pp. 371-377 ◽  
Author(s):  
Xiang-Yang Ma ◽  
Qing-Shui Yin ◽  
Zeng-Hui Wu ◽  
Hong Xia ◽  
Jing-Fa Liu ◽  
...  
Keyword(s):  
Pedicle Screws ◽  
Lateral Mass ◽  
Lateral Mass Screws

Unilateral cervical facet dislocation: a biomechanical study of several constructs including unilateral lateral mass fixation supplemented by an interspinous cable

2012 ◽  
Vol 16 (3) ◽  
pp. 251-256 ◽  
Author(s):  
Ron I. Riesenburger ◽  
Tejaswy Potluri ◽  
Nikhil Kulkarni ◽  
William Lavelle ◽  
Marie Roguski ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Gold Standard ◽  
Biomechanical Study ◽  
Anterior Cervical Discectomy ◽  
Lateral Mass ◽  
Intact Specimen ◽  
Cervical Discectomy ◽  
Lateral Mass Screws ◽  
The Right ◽  
Cervical Facet

Object Both ventral and dorsal operative approaches have been used to treat unilateral cervical facet injuries. The gold standard ventral approach is anterior cervical discectomy and fusion. There is, however, no clear gold standard dorsal operation. In this study, the authors tested the stability of multiple posterior constructs, including unilateral lateral mass fixation supplemented by an interspinous cable. Methods Six fresh human cervical spine specimens (C3–T1) were tested by applying pure moments to the C-3 vertebral body in increments of 0.5 Nm from 0 Nm to 2.0 Nm. Each specimen was tested in the following 8 conditions (in the order shown): 1) intact; 2) after destabilization via injury to the C5–6 facet; 3) with bilateral C5–6 lateral mass screws and rods; 4) after further destabilization by creating a right unilateral lateral mass fracture of C-5 (which rendered secure screw placement into the right C-5 lateral mass impossible); 5) with unilateral left C5–6 lateral mass screws and rod; 6) with unilateral C5–6 lateral mass screws and rod supplemented with an interspinous cable; 7) with a bilateral multilevel dorsal construct C4–6; and 8) after a C5–6 anterior cervical discectomy and fusion (ACDF) procedure with a polyetheretherketone graft and plate. Results The bilateral C5–6 lateral mass construct reduced the range of C5–6 motion to 33.6% of normal. The unilateral C5–6 lateral mass construct resulted in an increased range of motion to 110.1% of normal. The unilateral lateral mass construct supplemented by an interspinous cable reduced the C5–6 range of motion to 89.4% of normal. The bilateral C4–6 lateral mass construct reduced the C5–6 range of motion to 44.2% of normal. The C5–6 ACDF construct reduced the C5–6 range of motion to 62.6% of normal. Conclusions The unilateral lateral mass construct supplemented by an interspinous cable does reduce range of motion compared with an intact specimen, but is significantly inferior to a C4–6 bilateral lateral mass construct. When using a dorsal approach, the unilateral construct with a cable should only be considered in selected instances.

Accuracy of freehand pedicle screws versus lateral mass screws in the subaxial cervical spine

2020 ◽  
Vol 8 (5) ◽  
pp. 1049-1058
Author(s):  
Hwee Weng Dennis Hey ◽  
Wen-Hai Zhuo ◽  
Yong Hao Joel Tan ◽  
Jiong Hao Tan
Keyword(s):  
Cervical Spine ◽  
Pedicle Screws ◽  
Lateral Mass ◽  
Subaxial Cervical Spine ◽  
Lateral Mass Screws

scholarly journals Biomechanical advantage of C1 pedicle screws over C1 lateral mass screws: a cadaveric study

2013 ◽  
Vol 23 (4) ◽  
pp. 724-731 ◽  
Author(s):  
Florian Fensky ◽  
Rebecca A. Kueny ◽  
Kay Sellenschloh ◽  
Klaus Püschel ◽  
Michael M. Morlock ◽  
...  
Keyword(s):  
Pedicle Screws ◽  
Cadaveric Study ◽  
Lateral Mass ◽  
Lateral Mass Screws

Distribution of in vivo and in vitro range of motion following 1-level arthroplasty with the CHARITÉ artificial disc compared with fusion

2008 ◽  
Vol 8 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Bryan W. Cunningham ◽  
Paul C. McAfee ◽  
Fred H. Geisler ◽  
Gwen Holsapple ◽  
Karen Adams ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Pedicle Screws ◽  
Investigational Device Exemption ◽  
Flexion Extension ◽  
Level Fusion ◽  
Vitro Data ◽  
In Vitro Data ◽  
Time Point

Object One of the goals of lumbar arthroplasty is to restore and maintain range of motion (ROM) and to protect adjacent levels from abnormal motion, which may be a factor in transition syndrome following arthrodesis. In this study, in vitro ROM results were compared with in vivo, 2-year postoperative radiographic ROM evaluations. Methods Radiographs of patients enrolled in the CHARITÉ investigational device exemption study were analyzed at baseline and at 2 years postoperatively. The ROM in flexion/extension at the implanted and adjacent levels was measured, normalized, and compared with ROM results obtained using cadaver (in vitro) evaluations. Results Preoperative ROM distributions in patients enrolled for arthroplasty or fusion at the L4–5 level was as follows: 28% motion was observed at L3–4, 35% at L4–5 and 37% at L5–S1. Following a one-level arthroplasty at L4–5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 36% at L3–4, 30% at L4–5 and 35% at L5–S1. Following a one-level fusion with BAK and pedicle screws at L4–5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 45% at L3–4, 9% at L4–5 and 46% at L5–S1. Conclusions The baseline as well as the 2-year in vivo data confirmed previously published in vitro data. One-level arthroplasty was shown herein to replicate the normal distribution of motion of the intact spine.

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