Computed tomography morphometric analysis of the central clival depression and petroclival angle for application of the presigmoid approach in the pediatric population

Abstract

Aims:Lateral transtemporal approaches are useful for addressing lesions located ventral to the brainstem, especially when the pathologic diagnosis of the tumor dictates that a gross or near total resection improves outcomes. One approach, the presigmoid approach receives little attention in the pediatric population thus far. We sought to characterize morphometric changes, particularly the clival depth and the petroclival Cobb angle, that occur in the temporal bones of children and draw implications about doing a presigmoid approach in children.Settings and Design:This study was a retrospective study performed at John Sealy Hospital, a level-one trauma center that takes care of pediatric injuries as well.Subjects and Methods:We performed a morphometric analysis of noncontrast computed tomography head studies in 96 boys and 67 girls. Central clival depth and petroclival angle were obtained in the axial plane at the level of the internal auditory meatus using the method described by Abdel Aziz et al.Statistical Analysis Used:Descriptive statistics and Student's t-test to compare groups were calculated using Microsoft Excel.Results:We found no gender difference in mean central clival depth or petroclival angle (P = 0.98 and P = 0.61, respectively). However, when we broke our cohort by age into those younger than 9 years of age and those 10 years or older, we found the petroclival angle decreased by 6.2° which was statistically significant (P < 0.000000006).Conclusions:These findings suggest that a presigmoid retrolabyrinthine approach is useful for children 9 years of age and younger as the petroclival angle appears to decrease resulting in a shallower clival depression in these patients.

Developmental Considerations in Pediatric Skull Base Surgery

“…The petroclival angle appears to decrease (become less obtuse) in children less than 9 years of age, a favorable anatomic feature that allows for improved access via presigmoid retrolabyrinthine approaches to pathology in the central clival depression-the space between the internal acoustic meatus and the jugular tubercle, due to a shallower clival depression. 34 Complications common to these procedures in the adult population-cerebrospinal fluid (CSF) leakage, hearing loss, transient facial neuropathy-are seen in the pediatric population as well, a finding borne out by our previous institutional experience 1 as well as the report of Jackson et al, who reported on a series of 15 patients undergoing transtemporal approaches with the assistance of a neuro-otologist. 35 The role of an experienced neuro-otologist is of particular importance in children because the mastoid air cells are less well developed, which make identification of the facial nerve and bony labyrinth more difficult 36 (►Fig.…”

Morphometric Study of the Posterior Fossa: Identification of Practical Parameters for Tailored Selection of Surgical Routes to the Petroclival Region

“…Some authors attempted to quantify the anatomical variability of certain aspects of the petroclival region, but these studies not only had small sample sizes but also measured a limited number of petroclival region anatomic parameters, [2][3][4][5][6] thus failing to provide a more comprehensive set of data to evaluate different vectors of an approach. In our study, we found that PCAs correlated positively with each other at both levels (carotid canal and IAC).…”

“…1 Access to the petroclival region has been the focus of multiple reports on surgical approaches. [1][2][3][4][5] The existing algorithms for choosing skull base approaches put minimal emphasis on the variability of bony anatomy among patients and its effect on the adequacy of the different surgical corridors. In this study, we evaluated the existence of variability in the bony anatomy of the posterior fossa in adults.…”