Caroticoclinoid Bar: A Systematic Review and Meta-Analysis of Its Prevalence and Potential Implications in Cerebrovascular and Skull Base Surgery

World Neurosurg. (2019) 124:267-276

The presence of a caroticoclinoid bar (CCB) has been implicated in both transcranial and endonasal surgery. Its morphology reflects differences in the microsurgical anatomy of the parasellar area and its manipulation during anterior or middle clinoidectomy can result in internal carotid artery injury. Although adjustment of the surgical technique according to the CCB anatomic variants is required for safe surgical access to the paraclinoid region, a review indicated the lack of a systematic assortment of reported data regarding the prevalence of the CCB. Thus, our objective was to systematically review and document the prevalence of the CCB and its anatomic variations.

METHODS: Three databases were systematically reviewed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement through August 2018 to identify relevant studies.

RESULTS: A total of 27 reports (7521 subjects or specimens, 14,449 sides) were included in the present meta-analysis. The overall pooled prevalence of the CCB was 32.6% (95% confidence interval [CI], 26.6%e38.8%) when measured in the subjects or specimens and 23.6% (95% CI, 19.7%e27.6%) when measured in each side. The overall prevalence of the CCB reported from imaging studies was 23.1% (95% CI, 8.9%e41.4%) for the subjects/specimens and 18.7% (95% CI, 12.6%e25.7%) for each side. The presence of the CCB was slightly more prevalent (P [ 0.050) on the right side.

CONCLUSIONS: Our results showed a considerable prevalence of the CCB, with lower prevalence rates found among imaging studies. Although meticulous preoperative investigation is mandatory, surgeons treating patients with parasellar pathologic entities should always be vigilant regarding the CCB.

Safety of drilling for clinoidectomy and optic canal unroofing in anterior skull base surgery

Clinoidectomy and optic canal unroofing

Acta Neurochir (2013) 155:1017–1024

Skull base drilling is a necessary and important element of skull base surgery; however, drilling around vulnerable neurovascular structures has certain risks. We aimed to assess the frequency of complications related to drilling the anterior skull base in the area of the optic nerve (ON) and internal carotid artery (ICA), in a large series of patients.

Methods We included anterior skull base surgeries performed from 2000 to 2012 that demanded unroofing of the optic canal, with extra- or intradural clinoidectomy and/or drilling of the clinoidal process and lateral aspect of the tuberculum sella. Data was retrieved from a prospective database and supplementary retrospective file review. Our IRB waived the requirement for informed consent. The nature and location of pathology, clinical presentation, surgical techniques, surgical morbidity and mortality, pre- and postoperative vision, and neurological outcomes were reviewed.

Results There were 205 surgeries, including 22 procedures with bilateral optic canal unroofing (227 optic canals unroofed). There was no mortality, drilling-related vascular damage, or brain trauma. Complications possibly related to drilling included CSF leak (6 patients, 2.9 %), new ipsilateral blindness (3 patients, 1.5 %), visual deterioration (3 patients, 1.5 %), and transient oculomotor palsy (5 patients, 2.4 %). In all patients with new neuropathies, the optic and oculomotor nerves were manipulated during tumor removal; thus, new deficits could have resulted from drilling, or tumor dissection, or both.

Conclusion Drilling of the clinoid process and tuberculum sella, and optic canal unroofing are important surgical techniques, which may be performed relatively safely by a skilled neurosurgeon.

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