Hussam Metwali, Mario Giordano, Katja Kniese and Rudolf Fahlbusch
The aim of this study was to test the prognostic significance of intraoperative changes in the fractional anisotropy (FA) and the volume of the optic chiasma and their correlation with visual outcome.
Twenty-eight sequential patients with suprasellar tumors presenting with chiasma compression syndrome were surgically treated under intraoperative MRI control between March 2014 and July 2016. The FA and the volume of the optic chiasma were measured immediately before and immediately after tumor resection. The visual impairment score (VIS) was used to quantify the severity of the ophthalmological disturbances before surgery, 10–14 days after surgery, and again 3 months thereafter. The change in the FA and the volume of the optic chiasma was correlated to the improvement of vision. The correlation between other predictors such as the age of the patients and the duration of symptoms and the visual outcome was tested.
The VIS improved significantly after surgery. The FA values of the optic chiasma decreased significantly after decompression, whereas the volume of the optic chiasma increased significantly after decompression. The early and delayed improvement of vision was strongly correlated to the decrease in the average FA and the increase of the volume of the optic chiasma. The duration of symptoms showed a significant negative correlation to the visual outcome. However, the decrease in the FA showed the strongest correlation to the improvement of the VIS, followed by the expansion of the optic chiasma, and then the duration of symptoms.
The decrease in the FA and the expansion of the optic chiasma after its decompression are strong early predictors of the visual outcome. These parameters are also able to predict delayed improvement of vision.
Hussam Metwali, Katja Kniese, Babak Kardavani, Venelin Gerganov and Madjid Samii
The purpose of this prospective study was to evaluate the dysfunction of the nervus intermedius (NI) after vestibular schwannoma (VS) surgery. The authors present a clinically feasible method for this purpose.
In this prospective study, the authors included 30 patients who underwent surgery at the International Neuroscience Institute between May 2014 and February 2017 for resection of VS. The patients’ taste sensation was examined using taste strips. Lacrimation was tested using the Schirmer I test. The clinical evaluation was performed before surgery and repeated at 2 weeks and at 6 months after surgery as well as during the follow-up, which extended up to 2 years. The authors tested the correlation between the NI dysfunctions and the House-Brackmann grade of facial nerve palsy.
The taste sensation was lost on the side of surgery in 2 patients (6.6%) and decreased in 4 patients (13.3%). The disturbance of taste sensation was not statistically correlated with dysfunctions of the motor portion of the facial nerve. The taste impairment resolved in 4 patients within 6 months, but 2 patients suffered from persistent loss of the taste sensation on the side of surgery during the follow-up. In 23 patients (76.6%), the baseline lacrimation was lower on the side of surgery, and it was significantly correlated with outcome for dysfunctions of the motor portion of the facial nerve. During the follow-up, baseline lacrimation improved in correlation with the improvement in the dysfunctions of the motor portion of the facial nerve. None of the patients reported change in salivation or nasal secretion.
The NI can be affected after VS surgery. The disturbance of baseline lacrimal secretion was correlated with dysfunctions of the motor portion of the facial nerve. However, the disturbance of the taste sensation was not correlated with the grade of facial nerve palsy. Dysfunctions of the NI should be evaluated and separately reported while analyzing facial nerve outcome after VS surgery.