Lesions confined to the sphenoid ridge: differential diagnosis and surgical treatment

Anatomical features of the sphenoid ridge in the pediatric population

PURPOSE

To describe the relation of the sphenoid ridge (SR) with the surrounding anatomical structures in healthy children when approaching the anterior and middle fossae.

METHODS

Computed tomography of 180 pediatric patients (90 males / 90 females), aged 1-18 years were included the study. The size of the lesser wing (LW) and the distances of the LW to certain landmarks were measured.

RESULTS

The LW length was 28.48 ± 8.15 mm. The LW widths at the midline and the midpoint and lateral point of the SR were 7.78 ± 1.74 mm, 2.84 ± 0.81 mm, and 1.91 ± 0.64 mm, respectively. The distance between the midpoint of the SR and the crista galli was 28.22 ± 5.56 mm, and the distance between the crista alaris and internal auditory meatus was 51.73 ± 5.79 mm. The linear function was calculated as y = 18.748 + 1.024 × age for SR length, y = 6.046 + 0.182 × age for the midline width of SR, y = 2.367 + 0.050 × age for the midpoint width of SR, y = 1.249 + 0.069 × age for the crista alaris width, y = 21.727 + 0.683 × age for the distance between the SR midpoint and the crista galli, and y = 43.614 + 0.855 × age for the distance between the crista alaris and internal auditory meatus.

CONCLUSION

All measured parameters increased irregularly with advancing age. Furthermore, our regression equations representing the growth dynamics of SR may be used to estimate these parameters.

Zygomatic-transmandibular approach for giant tumors of the infratemporal fossa and parapharyngeal space

OBJECTIVE

The surgical anatomy of the infratemporal fossa and parapharyngeal space is often not properly understood by neurosurgeons, because these areas are more related to other medical disciplines. This article provides a detailed description of the infratemporal fossa and parapharyngeal space anatomy in cadaveric specimens and offers a neurosurgical perspective on a surgical approach that allows wide exposure and complete resection of giant tumors in this location.

METHODS

Ten cadaveric specimens were prepared for anatomic study. Dissections were performed to emphasize the relationship between bone, muscles, and neurovascular structures and to simultaneously expose the middle cranial fossa, the infratemporal fossa, and the parapharyngeal space. Ten patients with giant lesions in these areas (with maximum tumor diameter >8 cm) were treated via this approach.

RESULTS

The main obstacles to approaching the infratemporal fossa and the parapharyngeal space are the zygomatic arch, the parotid gland, the facial nerve, and the ascending ramus of the mandible. Thus, by combining a pterional-zygomatic craniotomy with transmandibular access, working up and down the parotid gland, the exposure is wider and safer. Among the 10 patients treated, tumors were totally resected in 7, subtotally resected in 2, and partially resected in 1. Morbidity was unremarkable, and, in 8 patients, clinical status improved dramatically.

CONCLUSION

The zygomatic-transmandibular approach allows resection of giant lesions in the middle cranial base, when they are invading the infratemporal fossa and parapharyngeal space, with a low morbidity rate.