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BACKGROUND Tumors involving the sellar area often cause visual disorders due to optic nerves/chiasm compression, so that surgery is required. However the likelihood of visual improvement/restoration is variable. Optical coherence tomography (OCT) is a valid diagnostic tool for defining pathological conditions of the optic apparatus. We herein investigated the role of the SD-OCT and the best corrected visual acuity in predicting postoperative visual recovery, in patients complaining of chiasm compression due to sellar-suprasellar lesions. MATERIALS AND METHODS We retrospectively analyzed 20 patients (7 females and 13 males; mean age 50,8 ± 17,87 years, range 11-83), with optic chiasm/nerve compression that underwent endoscopic endonasal approach at the Division of Neurosurgery of the Universita degli Studi di Napoli "Federico II", Naples - Italy, between June 2014 and February 2015. Pre-operative ophthalmological assessment focused on BCVA Snellen charts, Standard Automated Perimetry test and SD-OCT. Test were repeated at two weeks, one and three months after surgery. RESULTS A significant thickness reduction in all the patients, as compared to the control group was noted: GCC thickness reduction remained mostly unchanged postoperatively. 42.9% of the patients had altered visual acuity (VA), while the Perimetry revealed 90% of altered preoperative MD values (MD> -2.00): perimetry improvement was noted in 93% of cases and visual acuity in 91.3% of cases. A direct correlation between preoperative retinal status and functional recovery was identified considering the values of pRNFL and GCC. CONCLUSIONS OCT provides valuable information in regards to the entity of compression also in patients without any visual field defects. Although several factors should be taken into consideration, we retain that preoperative RNFL and GCC thickness values can be claimed as a reliable predictors of visual recovery in those patients presenting chiasm compression.

OBJECTIVEThe 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.METHODSSix 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.RESULTSThe 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).CONCLUSIONSBone 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.

AIM To analyze the impact of intraoperative neurophysiological monitoring (IONM) on the extent of removal and long-term neurological outcomes in a series of grade II ependymomas. MATERIAL AND METHODS We retrospectively reviewed 88 consecutive patients who underwent surgical resection of an intramedullary spinal cord tumor (IMSCT) at the Clinic of Neurosurgery of the Clinical Center of Serbia in Belgrade between January 2012 and December 2017. In all, 39 patients (25 males and 14 females; mean age 46.16 years) with grade II ependymomas were enrolled in this study; the mean follow-up time was 49.84 months. The modified McCormick Scale (mMCS) was used to assess the short- and long-term outcomes, and the patients were divided into two groups based on whether they underwent IONM. RESULTS The gross-total removal rate was 89.7%, and it was not influenced by use of IONM, location or tumor size. Upon admission,43.2% of the patients were dependent (grades IV and V), while 56.8% were independent (grades I, II and III), according to the mMCS. After 3 months of follow-up, 76.9% of the patients maintained or improved their neurological status, but this percentage was reduced after long-term follow-up. CONCLUSION Total surgical resection with good neurological outcomes can be achieved in the vast majority of patients with grade II ependymomas; it is important to emphasize that the use of IONM allows acceptable extent of resection and provides better results in terms of functional outcomes, with lower morbidity rates. Therefore, no correlation was demonstrated between the decrease in the basal amplitudes of IONM and D-waves and poor neurological outcomes.

While the subtemporal approach represents the surgical module milestone designed to reach the petrous apex, a novel ventral route, which is the superior eyelid endoscopic transorbital approach, has been proposed to access the skull base. Accordingly, we aimed to evaluate the feasibility of this route to the petrous apex, providing a qualitative and quantitative analysis of this relatively novel pathway. Five human cadaveric heads were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. After proper dissection planning, anterior petrosectomy via the endoscopic transorbital route was performed. Specific quantitative analysis, as well as dedicated three-dimensional reconstruction, was done. Using the endoscopic transorbital approach, it was possible to reach the petrous apex with an average volume bone removal of 1.33 ± 0.21 cm3. Three main intradural spaces were exposed: cerebellopontine angle, middle tentorial incisura, and ventral brainstem. The first one was bounded by the origin of the trigeminal nerve medially and the facial and vestibulocochlear nerves laterally, the second extended from the origin of the oculomotor nerve to the entrance of the trochlear nerve into the tentorium free edge while the ventral brainstem area was hardly accessible through the straight, ventral endoscopic transorbital trajectory. This is the first qualitative and quantitative anatomic study concerning details of the lateral aspect of the incisura and ventrolateral posterior fossa reached via the transorbital window. This manuscript is intended as a feasibility anatomic study, and further clinical contributions are mandatory to confirm the effectiveness of this approach, defining its possible role in the neurosurgical armamentarium.