An anatomical study comparing standard fluoroscopy and virtual fluoroscopy for the placement of C1–2 transarticular screws

2005 ◽  
Vol 2 (5) ◽  
pp. 584-588 ◽  
Author(s):  
Tony Tannoury ◽  
Adam C. Crowl ◽  
Todd C. Battaglia ◽  
Donald P. K. Chan ◽  
D. Greg Anderson
Keyword(s):  
Surgical Techniques ◽  
Anatomical Study ◽  
Careful Analysis ◽  
Screw Placement ◽  
Procedure Time ◽  
Transarticular Screw ◽  
Surgical Time ◽  
Content Type ◽  
Radiation Time ◽  
Fine Print

Object. The authors sought to compare radiation exposure, surgical time, and accuracy of screw placement when using either standard fluoroscopy or virtual fluoroscopy for the placement of C1–2 transarticular screws. Methods. Twenty-two C1–2 transarticular screws were placed in 11 cadavers in a randomized and alternating order by using either standard fluoroscopy or virtual fluoroscopy (fluoronavigation). The radiation time, procedure time, and accuracy of screw placement were recorded and statistically compared. A small but statistically significant reduction in fluoroscopy time was noted with the virtual fluoroscopy technique but the surgical times were similar between the two techniques. The incidence of noncritical and critical breaches (those at risk of causing a neurovascular injury) was not significantly different between the two groups. Careful analysis of the C1–2 anatomy in these specimens underscored the importance of placing the screw path in a maximally dorsal and medial portion of the C-2 isthmus to avoid injury to the vertebral artery and to maximize the bone purchase of the C-1 lateral mass. Conclusions. Although virtual fluoroscopy may represent a useful tool for transarticular screw placement, it does not supplant traditional surgical techniques and does not appear to lower the incidence of bone breaches that can occur when performing this demanding procedure.

Effect of frameless stereotaxy on the accuracy of C1–2 transarticular screw placement

2001 ◽  
Vol 95 (1) ◽  
pp. 74-79 ◽  
Author(s):  
Orin Bloch ◽  
Langston T. Holly ◽  
Jongsoo Park ◽  
Chinyere Obasi ◽  
Kee Kim ◽  
...  
Keyword(s):  
Image Guidance ◽  
Vascular Anatomy ◽  
Ct Scanning ◽  
Screw Placement ◽  
Frameless Stereotaxy ◽  
Transarticular Screw ◽  
Anterior Cortex ◽  
Content Type ◽  
Pars Interarticularis ◽  
Fine Print

Object. In recent studies some authors have indicated that 20% of patients have at least one ectatic vertebral artery (VA) that, based on previous criteria in which preoperative computerized tomography (CT) and standard intraoperative fluoroscopic techniques were used, may prevent the safe placement of C1–2 transarticular screws. The authors conducted this study to determine whether frameless stereotaxy would improve the accuracy of C1–2 transarticular screw placement in healthy patients, particularly those whom previous criteria would have excluded. Methods. The authors assessed the accuracy of frameless stereotaxy for C1–2 transarticular screw placement in 17 cadaveric cervical spines. Preoperatively obtained CT scans of the C-2 vertebra were registered on a stereotactic workstation. The dimensions of the C-2 pars articularis were measured on the workstation, and a 3.5-mm screw was stereotactically placed if the height and width of the pars interarticularis was greater than 4 mm. The specimens were evaluated with postoperative CT scanning and visual inspection. Screw placement was considered acceptable if the screw was contained within the C-2 pars interarticularis, traversed the C1–2 joint, and the screw tip was shown to be within the anterior cortex of the C-1 lateral mass. Transarticular screws were accurately placed in 16 cadaveric specimens, and only one specimen (5.9%) was excluded because of anomalous VA anatomy. In contrast, a total of four specimens (23.5%) showed significant narrowing of the C-2 pars interarticularis due to vascular anatomy that would have precluded atlantoaxial transarticular screw placement had previous nonimage-guided criteria been used. Conclusions. Frameless stereotaxy provides precise image guidance that improves the safety of C1–2 transarticular screw placement and potentially allows this procedure to be performed in patients previously excluded because of the inaccuracy of nonimage-guided techniques.

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.

Surgical anatomy of the C-2 pedicle

2001 ◽  
Vol 95 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Jay U. Howington ◽  
John J. Kruse ◽  
Deepak Awasthi
Keyword(s):  
Sagittal Plane ◽  
Pedicle Screws ◽  
Anatomical Study ◽  
Ct Scanning ◽  
Surgical Anatomy ◽  
Screw Placement ◽  
Preoperative Imaging ◽  
Direct Visualization ◽  
Content Type ◽  
Fine Print

Object. The goal of this anatomical study was to investigate the surgical and radiographic anatomy of the C-2 pedicle in relation to transpedicular screw placement in occipitocervical stabilization and to establish anatomical guidelines for the placement of C-2 pedicle screws. Methods. The C-2 pedicles in 10 cadaveric spines were evaluated using both computerized tomography (CT) scanning and manual measurements. The specimens were scanned; the mediolateral and rostrocaudal angulations of each pedicle were measured, with the midline sagittal plane and the inferior endplate of the C-2 facet, respectively, as references, and values were recorded in 1° increments by using a digital goniometer. The height, width, and length of the pedicles were also measured on the CT scans. Based on these measurements in conjunction with direct visualization of the C-2 pedicle through the C1–2 interlaminar space pedicle screws were then placed. The distances from the screw entry point to the midline, C2–3 joint line, and the medial aspect of the vertebral artery were also measured. Repeated CT scanning was then performed to assess screw placement. The average pedicle height, width, and length measured 9.1 mm, 7.9 mm, and 16.6 mm, respectively, and the medial inclination and rostrocaudal angulation averaged 35.2° and 38.8°, respectively. The cortex of the pedicle was not violated in any of the 20 cadaveric specimens. Conclusions. Adequate preoperative imaging studies in conjunction with direct visualization of the C-2 pedicle make transpedicular fixation safe and effective.

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.

Lack of agreement between direct magnetic resonance imaging and statistical determination of a subthalamic target: the role of electrophysiological guidance

2002 ◽  
Vol 97 (3) ◽  
pp. 591-597 ◽  
Author(s):  
Emmanuel Cuny ◽  
Dominique Guehl ◽  
Pierre Burbaud ◽  
Christian Gross ◽  
Vincent Dousset ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Functional Response ◽  
Anterior Commissure ◽  
Surgical Techniques ◽  
High Frequency Stimulation ◽  
Mr Images ◽  
Posterior Commissure ◽  
Content Type ◽  
Fine Print

Object. The goal of this study was to determine the most suitable procedure(s) to localize the optimal site for high-frequency stimulation of the subthalamic nucleus (STN) for the treatment of advanced Parkinson disease. Methods. Stereotactic coordinates of the STN were determined in 14 patients by using three different methods: direct identification of the STN on coronal and axial T2-weighted magnetic resonance (MR) images and indirect targeting in which the STN coordinates are referred to the anterior commissure—posterior commissure (AC—PC) line, which, itself, is determined either by using stereotactic ventriculography or reconstruction from three-dimensional (3D) MR images. During the surgical procedure, electrode implantation was guided by single-unit microrecordings on multiple parallel trajectories and by clinical assessment of stimulations. The site where the optimal functional response was obtained was considered to be the best target. Computerized tomography scanning was performed 3 days later and the scans were combined with preoperative 3D MR images to transfer the position of the best target to the same system of stereotactic coordinates. An algorithm was designed to convert individual stereotactic coordinates into an all-purpose PC-referenced system for comparing the respective accuracy of each method of targeting, according to the position of the best target. Conclusions. The target that is directly identified by MR imaging is more remote (mainly in the lateral axis) from the site of the optimal functional response than targets obtained using other procedures, and the variability of this method in the lateral and superoinferior axes is greater. In contrast, the target defined by 3D MR imaging is closest to the target of optimal functional response and the variability of this method is the least great. Thus, 3D reconstruction adjusted to the AC—PC line is the most accurate technique for STN targeting, whereas direct visualization of the STN on MR images is the least effective. Electrophysiological guidance makes it possible to correct the inherent inaccuracy of the imaging and surgical techniques and is not designed to modify the initial targeting.

The crucial decade: modern neurosurgery's definitive development in Harvey Cushing's early research and practice, 1900 to 1910

1997 ◽  
Vol 87 (6) ◽  
pp. 964-971 ◽  
Author(s):  
Samuel H. Greenblatt
Keyword(s):  
Clinical Success ◽  
Surgical Techniques ◽  
Scientific Work ◽  
The United States ◽  
Full Time ◽  
Content Type ◽  
Social Ability ◽  
Harvey Cushing ◽  
Neurological Surgery ◽  
Fine Print

✓ When Harvey Cushing announced his full-time commitment to neurological surgery in 1904, it was a discouraging and discouraged enterprise. Other surgeons' mortality rates for patients with brain tumors were 30 to 50%. By 1910 Cushing had operated on 180 tumors; he had a thriving practice, with a patient mortality rate of less than 13%. The three essential ingredients of his success were: 1) a new surgical conceptualization of intracranial pressure (ICP); 2) technical innovations for controlling ICP; and 3) establishment of a large referral base. In the years 1901 through 1905, the implications of his research on the “Cushing reflex” were quickly translated into surgical techniques for controlling ICP. In the period between 1906 and 1910, Cushing built up his referral practice by publishing widely, and especially by lecturing to medical audiences throughout the United States and Canada. His scientific work on ICP was essential to his clinical success, but without his professional and social ability to build a thriving practice, there would have been insufficient material for him to use to improve his approaches.

A new table-fixed retractor for anterior odontoid screw fixation

2003 ◽  
Vol 98 (3) ◽  
pp. 294-296 ◽  
Author(s):  
Jonathan S. Hott ◽  
Jeffrey S. Henn ◽  
Volker K. H. Sonntag
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Screw Fixation ◽  
Laryngeal Nerve ◽  
Screw Placement ◽  
Tubular Retractor ◽  
Content Type ◽  
Longus Colli ◽  
Fine Manipulation ◽  
Biplanar Fluoroscopy ◽  
Fine Print

✓ The authors describe a unique retraction device adapted for anterior odontoid screw placement. A rigidly fixed tubular retractor system obviates the need for dissecting the longus colli muscles as well as for excessive retraction of the trachea, esophagus, and recurrent laryngeal nerve. The proper trajectory for screw placement can be determined by fine manipulation of the retractor as determined by biplanar fluoroscopy. The retractor is then rigidly fixed in position. The tubular corridor permits the odontoid screw to be placed in the usual fashion.

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.

Vertebral artery injury in C1–2 transarticular screw fixation: results of a survey of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves

1998 ◽  
Vol 88 (4) ◽  
pp. 634-640 ◽  
Author(s):  
Neill M. Wright ◽  
Carl Lauryssen
Keyword(s):  
Vertebral Artery ◽  
Neurological Deficit ◽  
Peripheral Nerves ◽  
Balloon Occlusion ◽  
Neurological Deficits ◽  
Transarticular Screw ◽  
Content Type ◽  
Iatrogenic Complications ◽  
Number Of Patients ◽  
Fine Print

Object. The 847 active members of the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Section on Disorders of the Spine and Peripheral Nerves were surveyed to quantitate the risk of vertebral artery (VA) injury during C1–2 transarticular screw placement. Methods. This retrospective study elicited the number of patients treated with transarticular screws, the number of screws placed, the incidence of VA injury and subsequent neurological deficit, and the management of known or suspected VA injury. Two hundred thirteen (25.1%) of the 847 surgeons responded. One hundred one respondents (47.4%) had placed a total of 2492 C1–2 transarticular screws in 1318 patients. Thirty-one patients (2.4%) had known VA injuries and an additional 23 patients (1.7%) were suspected of having injuries. However, only two (3.7%) of the 54 patients with known or suspected VA injuries exhibited subsequent neurological deficits and only one (1.9%) died of bilateral VA injury. Other iatrogenic complications included dural tears, screw fractures, screw breakout, fusion failure, infection, and suboccipital numbness. Conclusions. Including both known and suspected cases, the risk of VA injury was 4.1% per patient or 2.2% per screw inserted. The risk of neurological deficit from VA injury was 0.2% per patient or 0.1% per screw, and the mortality rate was 0.1%. The choice of management of intraoperative VA injuries was evenly divided between placing the patient under observation and initiating immediate postoperative angiography with possible balloon occlusion.

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