Congenital Malrotation of the Atlas with Unilateral Hypertrophy of the Atlanto-occipital Joint-A Rare Anomaly of the Craniovertebral Junction and Its Management

Quantitative Anatomic Comparison of the Extreme Lateral Transodontoid vs Extreme Medial Endoscopic Endonasal Approaches to the Jugular Foramen and Craniovertebral Junction

BACKGROUND

Large, destructive intracranial and extracranial lesions at the jugular foramen (JF) and anterior craniovertebral junction (CVJ) are among the most challenging lesions to resect.

OBJECTIVE

To compare the extreme lateral transodontoid approach (ELTOA) with the extreme medial endoscopic endonasal approach (EMEEA) to determine the most effective surgical approach to the JF and CVJ.

METHODS

Seven formalin-fixed cadaveric heads were dissected. Using neuronavigation, we quantitatively measured and compared the exposure of the intracranial and extracranial neurovascular structures, the drilled area of the clivus and the C1 vertebra, and the area of exposure of the brainstem.

RESULTS

The mean total drilled area of the clivus was greater with the EMEEA than with the ELTOA (1043.5 vs 909.4 mm2, P = .02). The EMEEA provided a longer exposure of the extracranial cranial nerves (CNs) IX, X, and XI compared with the ELTOA (cranial nerve [CN] IX: 18.8 vs 12.0 mm, P = .01; CN X: 19.2 vs 10.4 mm, P = .003; and CN XI, 18.1 vs 11.9 mm, P = .04). The EMEEA, compared with the ELTOA, provided a significantly greater area of exposure of the contralateral ventromedial medulla (289.5 vs 80.9 mm2, P < .001) and pons (237.5 vs 86.2 mm2, P = .005) but less area of exposure of the ipsilateral dorsolateral medulla (51.5 vs 205.8 mm2, P = .008).

CONCLUSION

The EMEEA and ELTOA provide optimal exposures to different aspects of the CVJ and JF. A combination of these approaches can compensate for their disadvantages and achieve significant exposure.

Extreme Lateral Approach to the Craniovertebral Junction: An Update

INTRODUCTION

The term 'extreme lateral approach' (ELA) was first introduced by Sen and Sekhar relatively recently (in 1990). Its definition varies and remains controversial, but it generally entails more aggressive bony removal than the far lateral approach (FLA).

GOAL

In this paper we review the relevant literature and weigh up the advantages and disadvantages of this approach. We propose methods to manage the complications resulting from the more invasive character of the ELA. Some modern trends regarding how to definitely distinguish the ELA from the FLA are also presented.

METHODS

Using the PubMed database, literature was collected on the relevant topics and subsequently reviewed. All up-to-date tips and tricks were carefully gathered, and current morbidity and mortality rates were obtained, as well as further perspectives.

RESULTS AND CONCLUSION

The morbidity associated with the ELA remains higher than that associated with the FLA, but the mortality nowadays is comparable. The ELA undoubtedly is a challenging procedure requiring deep insight into the relevant anatomy and its normal variants.