Andrea Ruggeri, Joaquim Enseñat, Alberto Prats-Galino, Antonio Lopez-Rueda, Joan Berenguer, Martina Cappelletti, Matteo De Notaris and Elena d'Avella
Neurosurgical management of many vascular and neoplastic lesions necessitates control of the internal carotid artery (ICA). The aim of this study was to investigate the feasibility of achieving control of the ICA through the endoscopic endonasal approach by temporary occlusion with a Fogarty balloon catheter.
Ten endoscopic endonasal paraseptal approaches were performed on cadaveric specimens. A Fogarty balloon catheter was inserted through a sellar bony opening and pushed laterally and posteriorly extraarterially along the paraclival carotid artery. The balloon was then inflated, thus achieving temporary occlusion of the vessel. The position of the catheter was confirmed with CT scans, and occlusion of the ICA was demonstrated with angiography. The technique was performed in 2 surgical cases of pituitary macroadenoma with cavernous sinus invasion.
Positioning the Fogarty balloon catheter at the level of the paraclival ICA was achieved in all cadaveric dissections and surgical cases through a minimally invasive, quick, and safe approach. Inflation of the Fogarty balloon caused interruption of blood flow in 100% of cases.
Temporary occlusion of the paraclival ICA performed through the endoscopic endonasal route with the aid of a Fogarty balloon catheter may be another maneuver for dealing with intraoperative ICA control. Further clinical studies are required to prove the efficacy of this method.
Alberto Di Somma, Luigi Maria Cavallo, Matteo de Notaris, Domenico Solari, Thomaz E. Topczewski, Manuel Bernal-Sprekelsen, Joaquim Enseñat, Alberto Prats-Galino and Paolo Cappabianca
Different surgical routes have been used over the years to achieve adequate decompression of the optic nerve in its canal including, more recently, endoscopic approaches performed either through the endonasal corridor or the transorbital one. The present study aimed to detail and quantify the amount of bone removal around the optic canal, achievable via medial-to-lateral endonasal and lateral-to-medial transorbital endoscopic trajectories.
Five human cadaveric heads (10 sides) were dissected at the Laboratory of Surgical Neuroanatomy of the University of Barcelona (Spain). The laboratory rehearsals were run as follows: 1) preliminary preoperative CT scans of each specimen, 2) anatomical endoscopic endonasal and transorbital dissections and Dextroscope-based morphometric analysis, and 3) quantitative analysis of optic canal bone removal for both endonasal and transorbital endoscopic approaches.
The endoscopic endonasal route permitted exposure and removal of the most inferomedial portion of the optic canal (an average of 168°), whereas the transorbital pathway allowed good control of its superolateral part (an average of 192°). Considering the total circumference of the optic canal (360°), the transorbital route enabled removal of a mean of 53.3% of bone, mainly the superolateral portion. The endonasal approach provided bone removal of a mean of 46.7% of the inferomedial aspect. This result was found to be statistically significant (p < 0.05). The morphometric analysis performed with the aid of the Dextroscope (a virtual reality environment) showed that the simulation of the transorbital trajectory may provide a shorter surgical corridor with a wider angle of approach (39.6 mm; 46.8°) compared with the simulation of the endonasal pathway (52.9 mm; 23.8°).
Used together, these 2 endoscopic surgical paths (endonasal and transorbital) may allow a 360° decompression of the optic nerve. To the best of the authors' knowledge, this is the first anatomical study on transorbital optic nerve decompression to show its feasibility. Further studies and, eventually, surgical case series are mandatory to confirm the effectiveness of these approaches, thereby refining the proper indications for each of them.
Matteo de Notaris, Domenico Solari, Luigi M. Cavallo, Alfonso Iodice D'Enza, Joaquim Enseñat, Joan Berenguer, Enrique Ferrer, Alberto Prats-Galino and Paolo Cappabianca
The tuberculum sellae is a bony elevation ridge that lines up the anterior aspect of the sella, dividing it from the chiasmatic groove. The recent use of the endoscopic endonasal transtuberculum approach has provided surgeons with a method to reach the suprasellar area, offering a new surgical point of view somehow “opposite” of this area. The authors of this study aimed to define the tuberculum sellae as seen from the endoscopic endonasal view while also providing CT-based systematic measurements to objectively detail the anatomical features of such a structure, which was renamed the “suprasellar notch.”
The authors analyzed routine skull CT scans from 24 patients with no brain pathology or fractures and measured the interoptic distance at the level of the limbus sphenoidale, the chiasmatic groove sulcal length and width, and the angle of the suprasellar notch.
Indeed, the suprasellar notch was defined as the angle between 2 lines, the first passing through the tuberculum sellae midpoint and perpendicular to the cribriform plate, and a second line passing between 2 points, the midpoints of the limbus sphenoidale and the tuberculum sellae. Moreover, the authors performed on 15 cadaveric heads an endoscopic endonasal transplanum transtuberculum approach with the aid of a neuronavigator to achieve a step-by-step comparison with the radiological data. The whole CT scanning set was statistically analyzed to determine the statistical interdependency of the suprasellar notch angle with the other 3 measurements, that is, the sulcal length at the midline, the interoptic distance at the optic canal entrance, and the interoptic distance at the limbus.
Based on the endoscopic endonasal view and CT imaging analysis, the authors identified a certain anatomical variability and thus introduced a new classification of the suprasellar notch: Type I, angle < 118°; Type II, angle of 118°–138°; and Type III, angle > 138°. They then analyzed the surgical implications of the endoscopic endonasal approach to the suprasellar area, which could be affected by each of these structural types.
The new classification identifies 3 different types of suprasellar notch and, accordingly, their surgical relevance. Above all, the authors found that the different types of suprasellar notch can affect the osteodural defect reconstruction technique, namely the positioning/wedging of the buttress in the extradural space. A precise endoscopic anatomical knowledge of the neurovascular and bony relationships—especially in cases of a less pneumatized sphenoid sinus—is crucial when approaching the anterior skull base via a transtuberculum transplanum route.
Sergio García, Ramon Torné, Jhon Alexander Hoyos, Ana Rodríguez-Hernández, Sergio Amaro, Laura Llull, Antonio López-Rueda and Joaquim Enseñat
Reliable tools are lacking to predict shunt-dependent hydrocephalus (SDHC) development after aneurysmal subarachnoid hemorrhage (aSAH). Quantitative volumetric measurement of hemorrhagic blood is a good predictor of SDHC but might be impractical in the clinical setting. Qualitative assessment performed using scales such as the modified Fisher scale (mFisher) and the original Graeb scale (oGraeb) is easier to conduct but provides limited predictive power. In between, the modified Graeb scale (mGraeb) keeps the simplicity of the qualitative scales yet adds assessment of acute hydrocephalus, which might improve SDHC-predicting capabilities. In this study the authors investigated the likely capabilities of the mGraeb and compared them with previously validated methods. This research also aimed to define a tailored mGraeb cutoff point for SDHC prediction.
The authors performed retrospective analysis of patients admitted to their institution with the diagnosis of aSAH between May 2013 and April 2016. Out of 168 patients, 78 were included for analysis after the application of predefined exclusion criteria. Univariate and multivariate analyses were conducted to evaluate the use of all 4 methods (quantitative volumetric assessment and the mFisher, oGraeb, and mGraeb scales) to predict the likelihood of SDHC development based on clinical data and blood amount assessment on initial CT scans.
The mGraeb scale was demonstrated to be the most robust predictor of SDHC, with an area under the curve (AUC) of 0.848 (95% CI 0.763–0.933). According to the AUC results, the performance of the mGraeb scale was significantly better than that of the oGraeb scale (χ2 = 4.49; p = 0.034) and mFisher scale (χ2 = 7.21; p = 0.007). No statistical difference was found between the AUCs of the mGraeb and the quantitative volumetric measurement models (χ2 = 12.76; p = 0.23), but mGraeb proved to be the simplest model since it showed the lowest Akaike information criterion (66.4), the lowest Bayesian information criterion (71.2), and the highest R2
Nagelkerke coefficient (39.7%). The initial mGraeb showed more than 85% specificity for predicting the development of SDHC in patients presenting with a score of 12 or more points.
According to the authors’ data, the mGraeb scale is the simplest model that correlates well with SDHC development. Due to limited scientific evidence of treatments aimed at SDHC prevention, we propose an mGraeb score higher than 12 to identify patients at risk with high specificity. This mGraeb cutoff point might also serve as a useful prognostic tool since patients with SDHC after aSAH have worse functional outcomes.
Alberto Di Somma, Jorge Torales, Luigi Maria Cavallo, Jose Pineda, Domenico Solari, Rosa Maria Gerardi, Federico Frio, Joaquim Enseñat, Alberto Prats-Galino and Paolo Cappabianca
The extended endoscopic endonasal transtuberculum transplanum approach is currently used for the surgical treatment of selected midline anterior skull base lesions. Nevertheless, the possibility of accessing the lateral aspects of the planum sphenoidale could represent a limitation for such an approach. To the authors’ knowledge, a clear definition of the eventual anatomical boundaries has not been delineated. Hence, the present study aimed to detail and quantify the maximum amount of bone removal over the planum sphenoidale required via the endonasal pathway to achieve the most lateral extension of such a corridor and to evaluate the relative surgical freedom.
Six human cadaveric heads were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. The laboratory rehearsals were run as follows: 1) preliminary predissection CT scans, 2) the endoscopic endonasal transtuberculum transplanum approach (lateral limit: medial optocarotid recess) followed by postdissection CT scans, 3) maximum lateral extension of the transtuberculum transplanum approach followed by postdissection CT scans, and 4) bone removal and surgical freedom analysis (a nonpaired Student t-test). A conventional subfrontal bilateral approach was used to evaluate, from above, the bone removal from the planum sphenoidale and the lateral limit of the endonasal route.
The endoscopic endonasal transtuberculum transplanum approach was extended at its maximum lateral aspect in the lateral portion of the anterior skull base, removing the bone above the optic prominence, that is, the medial portion of the lesser sphenoid wing, including the anterior clinoid process. As expected, a greater bone removal volume was obtained compared with the approach when bone removal is limited to the medial optocarotid recess (average 533.45 vs 296.07 mm2; p < 0.01). The anteroposterior diameter was an average of 8.1 vs 15.78 mm, and the laterolateral diameter was an average of 18.77 vs 44.54 mm (p < 0.01). The neurovascular contents of this area were exposed up to the insular segment of the middle cerebral artery. The surgical freedom analysis revealed a possible increased lateral maneuverability of instruments inserted in the contralateral nostril compared with a midline target (average 384.11 vs 235.31 mm2; p < 0.05).
Bone removal from the medial aspect of the lesser sphenoid wing, including the anterior clinoid process, may increase the exposure and surgical freedom of the extended endoscopic endonasal transtuberculum transplanum approach over the lateral segment of the anterior skull base. Although this study represents a preliminary anatomical investigation, it could be useful to refine the indications and limitations of the endoscopic endonasal corridor for the surgical management of skull base lesions involving the lateral portion of the planum sphenoidale.