Anatomic Study of the Axis for Surgical Planning of Transarticular Screw Fixation

Igarashi, Tamaki; Kikuchi, Shinichi; Sato, Katsuhiko; Kayama, Satoru; Otani, Koji

doi:10.1097/00003086-200303000-00020

Cited by 77 publications

(37 citation statements)

References 19 publications

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“…Placement of either C1-C2 transarticular or C2 pedicle screws has a potential risk of vertebral artery injury [1][2][3][4][5][6][7][8][9][10][11][12][13][14]21]. The risk of vertebral artery injury by these two techniques needs to be carefully analyzed so as to allow the surgeon to choose the appropriate screw insertion method.…”

Section: Discussionmentioning

confidence: 99%

“…Vertebral artery injuries commonly occur if a drill, tap, or screw perforates or occludes the vertebral artery in the vertebral artery groove of C2, which is located on the lower surface of C2 and lateral to the pedicle ( Fig. 1) [1][2][3][4][5][6][7][8]. It has been suggested that C2 pedicle screw combined with C1 lateral mass screw placement is inherently safer than C1-C2 transarticular screw fixation in view of the risk of vertebral artery injury at C2, as the medially directed trajectory of the C2 pedicle screw carries the screw away from the vertebral artery, which normally is located lateral to the screw [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Risk of vertebral artery injury: comparison between C1–C2 transarticular and C2 pedicle screws

et al. 2013

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BACKGROUND CONTEXT: To our knowledge, no large series comparing the risk of vertebral artery injury by C1-C2 transarticular screw versus C2 pedicle screw have been published. In addition, no comparative studies have been performed on those with a high-riding vertebral artery and/ or a narrow pedicle who are thought to be at higher risk than those with normal anatomy. PURPOSE: To compare the risk of vertebral artery injury by C1-C2 transarticular screw versus C2 pedicle screw in an overall patient population and subsets of patients with a high-riding vertebral artery and a narrow pedicle using computed tomography (CT) scan images and threedimensional (3D) screw trajectory software. STUDY DESIGN: Radiographic analysis using CT scans. PATIENT SAMPLE: Computed tomography scans of 269 consecutive patients, for a total of 538 potential screw insertion sites for each type of screw. OUTCOME MEASURES: Cortical perforation into the vertebral artery groove of C2 by a screw. METHODS:We simulated the placement of 4.0 mm transarticular and pedicle screws using 1-mm-sliced CT scans and 3D screw trajectory software. We then compared the frequency of C2 vertebral artery groove violation by the two different fixation methods. This was done in the overall patient population, in the subset of those with a high-riding vertebral artery (defined as an isthmus height #5 mm or internal height #2 mm on sagittal images) and with a narrow pedicle (defined as a pedicle width #4 mm on axial images). RESULTS: There were 78 high-riding vertebral arteries (14.5%) and 51 narrow pedicles (9.5%). Most (82%) of the narrow pedicles had a concurrent high-riding vertebral artery, whereas only 54% of the high-riding vertebral arteries had a concurrent narrow pedicle. Overall, 9.5% of transarticular and 8.0% of pedicle screws violated the C2 vertebral artery groove without a significant difference between the two types of screws (p5.17). Among those with a high-riding vertebral artery, vertebral artery groove violation was significantly lower (p5.02) with pedicle (49%) than with transarticular (63%) screws. Among those with a narrow pedicle, vertebral artery groove violation was high in both groups (71% with transarticular and 76% with pedicle screws) but without a significant difference between the two groups (p5.55). CONCLUSIONS: Overall, neither technique has more inherent anatomic risk of vertebral artery injury. However, in the presence of a high-riding vertebral artery, placement of a pedicle screw is significantly safer than the placement of a transarticular screw. Narrow pedicles, which might be anticipated to lead to higher risk for a pedicle screw than a transarticular screw, did not result in a significant difference because most patients (82%) with narrow pedicles had a concurrent highriding vertebral artery that also increased the risk with a transarticular screw. Except in case of a high-riding vertebral artery, our results suggest that the surgeon can opt for either technique and expect similar anatomic risks of vertebral artery i...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Risk of vertebral artery injury: comparison between C1–C2 transarticular and C2 pedicle screws

et al. 2013

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“…Estos datos anatómicos sumado al hecho de que la lesión del vaso puede no asociarse a su oclusión definitiva pueden justificar esta falta de expresión clínica. La instrumentación transarticular C1-C2 está contraindicada ante la presencia de marcada cifosis, obesidad mórbida, tórax en tonel y ante la presencia de una anatomía desfavorable que es posible conocer de antemano con los estudios radiológicos 9,10 . La reducción de la subluxación, mediante tracción craneal, previo a la instrumentación, disminuye el riesgo de malposición de los tornillos y de complicaciones 10 .…”

Section: Discussionunclassified

Plasmocitoma de base craneal con inestabilidad cráneo-cervical

2009

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ResumenIntroducción. La inestabilidad cráneo-cervical constituye, en ocasiones, el principal problema neuroquirúrgico en la patología tumoral de la base craneal posterior. Presentamos un caso clínico en el que un plasmocitoma solitario originó inestabilidad cráneo-cervical. Durante la cirugía de estabilización, se lesionó la arteria vertebral. Revisamos la anatomía quirúrgica desde el punto de vista de la prevención de las complicaciones vasculares.Caso clínico. Mujer de 66 años diagnosticada de plasmocitoma solitario de base craneal, tratada con radio y quimioterapia con remisión completa, que presenta tetraparesia y disfagia. Tras el diagnóstico de inestabilidad cráneo-cervical, se indica estabilización mediante instrumentación occipito-cervical. Es intervenida bajo tracción craneal con atornillado C1-C2 según técnica de Magerl y extensión occipital. Durante la cirugía se lesionó la arteria vertebral derecha sin repercusión clínica. Dos años más tarde, la paciente es capaz de llevar una vida independiente.Conclusiones. La instrumentación cráneo-cervical con tornillos transarticulares C1-C2, como parte del sistema de fijación C0-C1-C2, parece eficaz para corregir la inestabilidad en lesiones osteolíticas, a expensas de un riesgo considerable de lesión de la arteria vertebral, especialmente en presencia de algunas variaciones anatómicas.PALABRAS CLAVE: Base craneal. Plasmocitoma solitario. Inestabilidad cráneo-cervical. Arteria vertebral. Instrumentación. Skull base plasmacytoma with craniocervical instability SummaryIntroduction. Cranio-cervical instability is, in some cases, the main surgical concern in posterior skull base tumors. We report on a case in which a solitary plasmacytoma of the skull base presented with cranio-cervical instability. Vertebral artery was injured during surgery. The surgical anatomy is reviewed, with emphasis in vascular complications avoidance.Case report. A 66 year-old woman was diagnosed of a cranial base solitary plasmacytoma and treated with radio and chemotherapy with complete remission. After receiving that treatment, she presented with tetraparesis and a cranio-cervical instability was diagnosed. She was operated on, under cranial traction, of posterior occipito-cervical instrumentation with C1 to C2 transarticular Magerl screws. The right vertebral artery was injured during surgery without additional neurological deficit. Two years after the operation she remains independent for daily activities.Conclusions. Transarticular screws at the C1 to C2 level of the cervical spine may provide rigid fixation in posterior cranio-cervical instrumentation for osteolytic lesions, but there is a risk of injury to the vertebral artery, specially when some variations in the surgical anatomy exist.KEY WORDS: Skull base. Solitary plasmacytoma. Craniocervical instability. Screw. Vertebral artery. IntroducciónLa estabilidad cráneo-cervical depende de la integridad de la base craneal posterior, el atlas, el axis, el complejo articular, ligamentario y muscular 13 . Diversos procesos de origen inf...

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“…9,10 This technique is generally made without using intraoperative fluoroscopy (free hand technique) and does pose a risk to the vertebral artery. Successful treatment of craniocervical fusions, atlantoaxial fixation and axis inclusion in subaxial fixation has been extensively reported in the literature.…”

Section: C2 Laminar Screw Fixation General Considerationsmentioning

confidence: 99%