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Morphometric three-dimensional computed tomography anatomy of the hypoglossal canal

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Abstract

Optimal surgical exposure during the transcondylar approach may result in injury to the hypoglossal nerve. This study evaluated the utility of three-dimensional computed tomography (3-D CT) as a means of obtaining detailed anatomic information in an individual patient prior to surgery involving the hypoglossal canal. We studied 20 hypoglossal canals in ten patients using 3-D CT reconstructed from 1-mm CT slices. Detailed anatomic measurements were performed to define the relationship of the hypoglossal canal to the occipital condyles and clivus. The relationship of the hypoglossal canal to the occipital condyles and clivus were extremely variable. From the outer table of the clivus in the midline, the extracranial opening of the hypoglossal canal was 20.3 + 2.7 mm (range 15.7–24.7 mm). The intracranial opening was 7.4 + 2.3 mm (range 6.2–11.5 mm) from the inner table of the clivus. From the superior aspect of the condyle, the inner opening was 11.0 + 1.4 mm (range 8.7–12.7 mm) and the outer opening was 19.1 + 2.4 mm (range 14.3–22.8 mm). From the lowest point of the condyle, the outer opening was 12.4 + 2.1 mm (range 9.1–15.6 mm). The posterior condylar emissary vein was 12.2 + 3.0 mm from the intracranial opening of the hypoglossal canal. Three-dimensional CT is a useful tool for assessing critical anatomic relationships and tailoring surgical approaches for individual patients. The amount of bone that can be safely removed without violating the hypoglossal canal can be determined preoperatively for each patient.

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References

  1. Bertalanffy H, Seeger W (1991) The dorsolateral, suboccipital, transcondylar approach to the lower clivus and anterior portion of the craniocervical junction. Neurosurgery 29:815–821

    Article  PubMed  CAS  Google Scholar 

  2. Bulsara KR, Leveque JC, Gray L, Fukushima T, Friedman AH, Villavicencio AT (2006) Three-dimensional computed tomographic analysis of the relationship between the arcuate eminence and the superior semicircular canal. Neurosurgery 59:ONS7–12, discussion ONS7–12

    Google Scholar 

  3. Fukushima T, Sameshima T (2004) Manual of skull base dissection. AF Neurovideo, INC, Raleigh

    Google Scholar 

  4. George B, Dematons C, Cophignon J (1988) Lateral approach to the anterior portion of the foramen magnum. Application to surgical removal of 14 benign tumors: technical note. Surg Neurol 29:484–490

    Article  PubMed  CAS  Google Scholar 

  5. Gilsbach JM, Eggert HR, Seeger W (1987) The dorsolateral approach in ventrolateral craniospinal lesions. Walter de Gruyter, Berlin

    Google Scholar 

  6. Katsuta T, Matsushima T, Wen HT, Rhoton AL (2000) Trajectory of the hypoglossal nerve in the hypoglossal canal: significance for the transcondylar approach. Neurol Med Chir (Tokyo) 40:206–209 discussion 210

    Article  CAS  Google Scholar 

  7. Matsushima T, Natori Y, Katsuta T, Ikezaki K, Fukui M, Rhoton AL (1998) Microsurgical anatomy for lateral approaches to the foramen magnum with special reference to transcondylar fossa (supracondylar transjugular tubercle) approach. Skull Base Surg 8:119–125

    PubMed  CAS  Google Scholar 

  8. Pernezky A (1986) The posterolateral approach to the foramen magnum. Springer, Berlin

    Google Scholar 

  9. Seeger W (1978) Atlas of topographical anatomy of the brain and surrounding structures. Springer, New York

    Google Scholar 

  10. Sen CN, Sekhar LN (1990) An extreme lateral approach to intradural lesions of the cervical spine and foramen magnum. Neurosurgery 27:197–204

    Article  PubMed  Google Scholar 

  11. Sen CN, Sekhar LN (1991) Surgical management of anteriorly placed lesions at the craniocervical junction—an alternative approach. Acta Neurochir (Wien) 108:70–77

    Article  CAS  Google Scholar 

  12. Spetzler RFGT (1990) The far-lateral approach to the inferior clivus and the upper region: technical note. Barrow Neurol Inst Q 6:35–38

    Google Scholar 

  13. Villavicencio AT, Leveque JC, Bulsara KR, Friedman AH, Gray L (2001) Three-dimensional computed tomographic cranial base measurements for improvement of surgical approaches to the petrous carotid artery and apex regions. Neurosurgery 49:342–352 discussion 352–343

    Article  PubMed  CAS  Google Scholar 

  14. Wen HT, Rhoton AL, Katsuta T, de Oliveira E (1997) Microsurgical anatomy of the transcondylar, supracondylar, and paracondylar extensions of the far-lateral approach. J Neurosurg 87:555–585

    Article  PubMed  CAS  Google Scholar 

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Authors and Affiliations

  1. Department of Neurosurgery, Skull Base Surgery and Neurovascular Program, Yale University School of Medicine, 333 Cedar Street, TMP 4, New Haven, CT, 06520, USA

    Ketan R. Bulsara

  2. Carolina Neuroscience Institute, Raleigh, NC, USA

    Katsuyuki Asaoka & Takanori Fukushima

  3. Division of Neurosurgery, Duke University, Durham, NC, USA

    Hamid Aliabadi, Charles Kanaly, Allan Friedman & Takanori Fukushima

Authors
  1. Ketan R. Bulsara
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  2. Katsuyuki Asaoka
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  3. Hamid Aliabadi
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  4. Charles Kanaly
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  5. Allan Friedman
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  6. Takanori Fukushima
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Corresponding author

Correspondence to Ketan R. Bulsara.

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Comments

Niklaus Krayenbühl, Zürich, Switzerland

The authors describe a morphometric analysis of the variations of the anatomy of the hypoglossal canal evaluated by 3-D computed tomography. They measured the relationship of the hypoglossal canal to the clivus, the occipital condyle, and the posterior condylar emissary vein and confirmed the variability in the location of the hypoglossal canal.

This paper reminds us that advanced imaging techniques, like three-dimensional CT, should be used to improve the preoperative understanding of the anatomy in individual patients. This will allow more precise planning of the surgical approach, increasing the safety for the patient.

Comments

Helmut Bertalanffy, Zürich, Switzerland

I fully agree with the authors that studying the anatomical configuration of the hypoglossal canal in thin-slice 3-D CT scans is very helpful for an optimal exposure and even to avoid injury to the hypoglossal canal. For me, the surgical exposure of the hypoglossal canal has similarities with exposing the optic canal from an extradural approach. By resecting the anterior clinoid process laterally, the surgeon gradually exposes the dural sheath of the optic nerve within the optic canal. In a same fashion, the surgeon can easily expose the hypoglossal canal by drilling the medial portion of the occipital condyle and then part of the jugular tubercle that is located above the hypoglossal canal. Another very important landmark is the condylar emissary vein located within a separate bony canal. This canal can sometimes be very large and, correspondingly, the vein may occasionally have a very large caliber. The condylar emissary vein always drains into the jugular bulb. I always use the information obtained from preoperative 3-D CT scans not only to study the variations of the hypoglossal canal but also to obtain information concerning the condylar emissary vein located in its vicinity.

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Bulsara, K.R., Asaoka, K., Aliabadi, H. et al. Morphometric three-dimensional computed tomography anatomy of the hypoglossal canal. Neurosurg Rev 31, 299–302 (2008). https://doi.org/10.1007/s10143-008-0143-7

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  • DOI: https://doi.org/10.1007/s10143-008-0143-7

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