SAFE ANGLE SCOPE FOR POSTERIOR ATLANTO-OCCIPITAL TRANSARTICULAR SCREW FIXATION

Neurosurgery ◽  
2009 ◽  
Vol 65 (3) ◽  
pp. 499-504 ◽  
Author(s):  
Wangjun Yan ◽  
Chengshi Zhang ◽  
Xuhui Zhou ◽  
Xiongsheng Chen ◽  
Wen Yuan ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Screw Fixation ◽  
Tomographic Reconstruction ◽  
Kirschner Wire ◽  
Screw Placement ◽  
X Rays ◽  
Transarticular Screw ◽  
Transarticular Screw Fixation ◽  
Computed Tomographic ◽  
Fresh Cadaver

Abstract OBJECTIVE To study the technical parameters related to, and explore the clinical significance of, posterior atlanto-occipital transarticular screw fixation. METHODS Posterior implantation of Kirschner wires via the atlanto-occipital joint was performed on 20 dry bone specimens with complete atlanto-occipital joints. The angle of the Kirschner wire was measured on a postimplantation x-ray. Three-dimensional computed tomographic reconstruction of the atlanto-occipital joint of 30 healthy adults was performed to measure the simulative safety range for screw placement in posterior atlanto-occipital transarticular screw fixation. The procedure was then conducted on 12 fresh cadaver occipitocervical specimens. X-rays and 3-dimensional computed tomographic reconstruction were performed postsurgery to verify exact screw positioning. RESULTS The ideal angles for screw placement were cephalocaudal angle in the sagittal plane of 53.3 ± 3.4 degrees, mediolateral angle in the coronal plane of 20.0 ± 2.6 degrees, a maximum allowable cephalocaudal angle of 74.6 ± 2.8 degrees (67.9–80.5 degrees), a minimum allowable cephalocaudal angle of 24.9 ± 1.9 degrees (22.1–29.4 degrees), a maximum allowable mediolateral angle of 40.5 ± 2.9 degrees (31.1–49.4 degrees), and a minimum allowable mediolateral angle of 0.7 ± 1.6 degrees (−4.1–5.9 degrees). Surgery simulation in the fresh cadaver specimens indicated that this safe scope is reliable. CONCLUSION There is a safe scope for the angle of the screw placement in posterior atlanto-occipital transarticular screw fixation. Posterior transarticular screw fixation can be safely performed for occipitocervical fusion fixation when utilizing careful screw placement.

Anatomical suitability of C1–2 transarticular screw placement in pediatric patients

2000 ◽  
Vol 92 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Douglas L. Brockmeyer ◽  
Julie E. York ◽  
Ronald I. Apfelbaum
Keyword(s):  
Pediatric Patients ◽  
Screw Fixation ◽  
Vascular Complications ◽  
Screw Placement ◽  
Atlantoaxial Instability ◽  
Os Odontoideum ◽  
Transarticular Screw ◽  
Content Type ◽  
Transarticular Screw Fixation ◽  
Fine Print

Object. Craniovertebral instability is a challenging problem in pediatric spinal surgery. Recently, C1–2 transarticular screw fixation has been used to assist in craniovertebral joint stabilization in pediatric patients. Currently there are no available data that define the anatomical suitability of this technique in the pediatric population. The authors report their experience in treating 31 pediatric patients with craniovertebral instability by using C1–2 transarticular screws. Methods. From March 1992 to October 1998, 31 patients who were 16 years of age or younger with atlantooccipital or atlantoaxial instability, or both, were evaluated at our institution. There were 21 boys and 10 girls. Their ages ranged from 4 to 16 years (mean age 10.2 years). The most common causes of instability were os odontoideum (12 patients) and ligamentous laxity (eight patients). Six patients had undergone a total of nine previous attempts at posterior fusion while at outside institutions. All patients underwent extensive preoperative radiological evaluation including fine-slice (1-mm) computerized tomography scanning with multiplanar reconstruction to evaluate the anatomy of the C1–2 joint space. Preoperatively, of the 62 possible C1–2 joint spaces in 31 patients, 55 sides (89%) were considered suitable for transarticular screw placement. In three patients the anatomy was considered unsuitable for bilateral screw placement. In three patients the anatomy was considered inadequate on one side. Fifty-five C1–2 transarticular screws were subsequently placed, and there were no neurological or vascular complications. Conclusions. The authors conclude that C1–2 transarticular screw fixation is technically possible in a large proportion of pediatric patients with craniovertebral instability.

The anatomical suitability of the C1–2 complex for transarticular screw fixation

1996 ◽  
Vol 85 (2) ◽  
pp. 221-224 ◽  
Author(s):  
Christopher G. Paramore ◽  
Curtis A. Dickman ◽  
Volker K. H. Sonntag
Keyword(s):  
Screw Fixation ◽  
Ct Scans ◽  
Screw Placement ◽  
Consecutive Series ◽  
Transarticular Screw ◽  
Transverse Foramen ◽  
Content Type ◽  
Transarticular Screw Fixation ◽  
The Right ◽  
Fine Print

✓ Posterior transarticular screw fixation of the C1–2 complex has become an accepted method of rigid internal fixation for patients requiring posterior C1–2 fusion. The principal limitation of this procedure is the location of the vertebral artery, because an anomalous position may prohibit screw placement. In this study, a consecutive series of computerized tomography (CT) scans was reviewed, and the suitability of each patient for transarticular screw fixation was evaluated. All of the fine-slice axial C1–2 CT scans and reconstructions performed on a spiral scanner over 2 years were reviewed. A novel screw trajectory reconstruction was designed to visualize the potential path of a transarticular screw in the plane of the reconstruction. Scans were reviewed for bone anatomy and the position of the transverse foramen. Seventeen (18%) of 94 patients had a high-riding transverse foramen on at least one side of the C-2 vertebra that would prohibit the placement of transarticular screws. The left side was involved in nine patients and the right in five. Three patients had bilateral anomalies. The mean age of the group with anomalies (35.9 years, range 10–76) was not significantly different from the overall mean age (35.7 years, range 6–94). An additional five patients (5%) were considered to have anatomy in which screw placement was feasible but risky. On the basis of these data, it is postulated that 18% to 23% of patients may not be suitable candidates for posterior C1–2 transarticular screw fixation on at least one side.

scholarly journals The anatomical suitability of C1-2 transarticular screw placement in pediatric patients

1999 ◽  
Vol 6 (6) ◽  
pp. E8
Author(s):  
Douglas L. Brockmeyer ◽  
Julie E. York ◽  
Ronald I. Apfelbaum
Keyword(s):  
Pediatric Patients ◽  
Screw Fixation ◽  
Pediatric Population ◽  
Vascular Complications ◽  
Joint Space ◽  
Screw Placement ◽  
Atlantoaxial Instability ◽  
Os Odontoideum ◽  
Transarticular Screw ◽  
Transarticular Screw Fixation

Craniovertebral instability is a challenging problem in pediatric spinal surgery. Recently, C1-2 transarticular screw fixation in pediatric patients has been used to assist in the stabilization of the craniovertebral joint. Currently there are no data that define the anatomical suitability of this technique in the pediatric population. The authors report their experience in 32 pediatric patients in whom craniovertebral instability was treated by placement of C1-2 transarticular screws. From March 1991 to October 1998, 32 patients 16 years of age or younger with atlantooccipital, or atlantoaxial instability, or both were evaluated at our institution. There were 22 boys and 10 girls. Their ages ranged from 4 to 16 years (mean age 10.2 years). The most common causes of instability were os odontoideum (12 patients) and ligamentous laxity (nine patients). Six patients had undergone a total of nine previous attempts at posterior fusion at outside institutions. All patients underwent extensive preoperative radiological evaluation including thin cut (1-mm) computerized tomography scanning with multiplanar reconstruction to evaluate the C1-2 joint space anatomy. Of the 64 possible C1-2 joint spaces in 32 patients, 55 sides (86%) were considered suitable for transarticular screw placement preoperatively. In three patients the C1-2 joint space anatomy was considered unsuitable for screw placement bilaterally. In three patients the anatomy was considered inadequate on one side. Fifty-five C1-2 transarticular screws were subsequently placed, with no resulting neurological or vascular complications. We conclude that C1-2 transarticular screw fixation is technically possible in a large proportion of pediatric patients with craniovertebral instability.

scholarly journals Evaluation of the efficiency of the C-ring aiming guide for atlantoaxial transarticular screw fixation in toy breed dogs

2019 ◽  
Vol 64 (No. 1) ◽  
pp. 18-24
Author(s):  
J.Y. Park ◽  
Y.R. Kim ◽  
H.J. Choi ◽  
Y.W. Lee ◽  
S.M. Jeong ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Cervical Vertebrae ◽  
Kirschner Wire ◽  
Insertion Time ◽  
Transarticular Screw ◽  
Vertebral Canal ◽  
Transarticular Screw Fixation ◽  
Insertion Angle ◽  
Drill Guide ◽  
Before And After

The goal of the present study was to evaluate the efficiency and safety of the C-ring aiming guide for the atlantoaxial transarticular screw fixation technique in toy breed dogs. Twenty-one adult canine cadavers of toy breed dogs were used in this study. The left and right sides of the cervical vertebrae were randomly assigned to two implant insertion groups: a C-ring aiming guide group and a drill guide group. A 1.2-mm Kirschner wire was inserted into each side by using either a C-ring aiming guide or a drill guide. CT scans were performed before and after surgery. The optimal safe implantation corridor angle and length, the implant insertion angle and length, the implant insertion time and the proportion of the insertion corridor to the optimal corridor were evaluated. Violations to the alar foramen and the vertebral canal also were evaluated. The implant insertion time was twice as long as that observed in the aiming guide group (P < 0.05). The proportion of the insertion angle and length to the optimal angle were not significantly different between groups (P > 0.05). With respect to precision, there was a trend toward less variability in the aiming guide group; however, this difference was not significant (P = 0.09). The violation of the alar foramen was significantly lower in the aiming guide group than in the drill guide group (P < 0.05). Violation to the vertebral canal was detected in one cadaver in the drill guide group but did not occur in the aiming guide group. The use of a C-ring aiming guide was associated with less damage to the alar foramen and the vertebral canal during atlantoaxial transarticular screw fixation in toy breed dogs.

Radiological and anatomical evaluation of the atlantoaxial transarticular screw fixation technique

1997 ◽  
Vol 86 (6) ◽  
pp. 961-968 ◽  
Author(s):  
Ali Abou Madawi ◽  
Adrian T. H. Casey ◽  
Guirish A. Solanki ◽  
Gerald Tuite ◽  
Robert Veres ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Screw Placement ◽  
Transoral Surgery ◽  
Spinal Instability ◽  
Lateral Mass ◽  
Transarticular Screw ◽  
Content Type ◽  
Posterior Surgery ◽  
Transarticular Screw Fixation ◽  
Fine Print

✓ Sixty-one patients treated with C1–2 transarticular screw fixation for spinal instability participated in a detailed clinical and radiological study to determine outcome and clarify potential hazards. The most common condition was rheumatoid arthritis (37 patients) followed by traumatic instability (15 patients). Twenty-one of these patients (onethird) underwent either surgical revision for a previously failed posterior fusion technique or a combined anteroposterior procedure. Eleven patients underwent transoral odontoidectomy and excision of the arch of C-1 prior to posterior surgery. No patient died, but there were five vertebral artery (VA) injuries and one temporary cranial nerve palsy. Screw malposition (14% of placements) was comparable to another large series reported by Grob, et al. There were five broken screws, and all were associated with incorrect placement. Anatomical measurements were made on 25 axis bones. In 20% the VA groove on one side was large enough to reduce the width of the C-2 pedicle, thus preventing the safe passage of a 3.5-mm diameter screw. In addition to the obvious dangers in patients with damaged or deficient atlantoaxial lateral mass, the following risk factors were identified in this series: 1) incomplete reduction prior to screw placement, accounting for two-thirds of screw complications and all five VA injuries; 2) previous transoral surgery with removal of the anterior tubercle or the arch of the atlas, thus obliterating an important fluoroscopic landmark; and 3) failure to appreciate the size of the VA in the axis pedicle and lateral mass. A low trajectory with screw placement below the atlas tubercle was found in patients with VA laceration. The technique that was associated with an 87% fusion rate requires detailed computerized tomography scanning prior to surgery, very careful attention to local anatomy, and nearly complete atlantoaxial reduction during surgery.

scholarly journals Subaxial subluxation after atlantoaxial transarticular screw fixation in rheumatoid patients

2009 ◽  
Vol 18 (6) ◽  
pp. 869-876 ◽  
Author(s):  
Hiromu Ito ◽  
Masashi Neo ◽  
Takeshi Sakamoto ◽  
Shunsuke Fujibayashi ◽  
Hiroyuki Yoshitomi ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Transarticular Screw ◽  
Transarticular Screw Fixation ◽  
Subaxial Subluxation
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