Based on their dural attachments, parasagittal meningiomas are considered as lesions attached to the superior sagittal sinus, while parafalcine meningiomas arise from falx and concealed completely by the overlying cortex, and typically, they do not involve superior sagittal sinus. Incidence of parasagittal meningiomas varies in literature from 16.8 to 25.6 of intracranial meningioma (Wilkins, 1991). The incidence of parafalcine meningioma is less frequent than parasagittal meningiomas; some authors considered falcine meningiomas are five to seven times less common than parasagittal meningiomas (Claus et al., 2005). Akira et al. (2012) reported 16 cases in their study, 12 cases were parasagittal while 4 cases were parafalcine meningioma. Shiro et al. (1990) reported the following incidence of parafalcine and parasagittal meningiomas at the middle and posterior one third: among 15 cases involving the middle third, 3 cases were parafalcine while 12 were parasagittal; in the posterior one third, one case was a parafalcine meningioma while 5 cases were parasagittal. In our study among 17 cases, 12 were parasagittal and 5 were parafalcine.
The main goal of surgical management of parasagittal and parafalcine meningiomas involving the middle third is to do complete excision and protect structures related to motor function, mainly the central gyrus, Rolandic vein, and superficial cortical draining veins; this seems to be not usually visible as in most of cases many difficulties were faced during surgery like large-sized tumors with high vascularity, sinus invasion, and involvements of major cortical veins. In our study, we achieved total resection of the lesion in all cases, according to Simpson’s classification, grade I resection was obtained in 4 patients and grade II was obtained in 13 patients. Intraoperative sinus invasion was present in 3 patients. We did not face recurrence within the follow-up period; this could be due to total resection obtained in all cases and no atypical changes or malignancy found in histopathological examination of excised lesions.
We focused in this study on motor power and function deterioration during early postoperative period and long-term follow-up as parasagittal and parafalcine meningiomas involving middle third are usually associated with a higher incidence of motor power deterioration, either as a presenting symptom or a postoperative complication. In a study done by Jian et al. (2013), the incidence of motor weakness as a presenting symptom was 61%. Shiro et al. (1990) reported an incidence of 40% in their study, while incidence was 0% among lesions involving anterior and posterior third in the same study. In our study, motor power deterioration was the presenting symptoms in 8 patients (47%), 5 cases classified as partial disability but independent (P), and 3 cases had complete disability (C).
Regarding motor function, many authors documented poor results during early postoperative period. Akira et al. (2012) reported an incidence around 50% in their study, where 8 patients out of 16 developed deterioration of motor power during early postoperative period, 6 cases showed hemiparesis, 5 of them had complete hemiplegia, and 2 cases showed monoparesis of the lower limb. Jian et al. (2013) reported that 56% of their patients with preoperative motor deficits developed worsening of motor function during early postoperative period (9 patients out of 16). In our study, in spite of doing all attempts to preserve and protect draining veins, peritumoral brain tissues, and superior sagittal sinus patency and integrity (starting from doing a wide craniotomy flap till following microsurgical technique for tumor resection), early postoperative outcome regarding motor power and function was around 53% (9 cases deteriorated out of 17). Among group A (9 patients with no deficit), 5 patients developed new motor deficits, and among group B (8 patients with previous motor deficit), 4 patients got more worsening of their deficits.
Venous system injury with subsequent cerebral edema, venous infarction, cortical injuries, and contusions are considered the main reasons for poor postoperative outcome regarding motor function (Tomasello et al., 2013; Bazzao et al., 2005; Elborady & Kamal, 2014). However, in many cases, there is no pathology detected in postoperative radiological studies (Na et al., 2013). Akira et al. (2012) reported that in their series in spite of 8 patients out of 16 who developed deterioration of motor power during early postoperative period, only radiological studies were positive in 2 cases only (one case showed intracerebral hematoma and the other showed severe cerebral edema). In our study, postoperative radiological studies were negative in 5 cases with motor power deterioration, while 3 cases showed severe cerebral edema that required intensive medical therapy, including deep sedation and ventilation, one case showed postoperative hemorrhagic infarctions subjected to medical treatment and no surgical intervention was required for any deteriorated cases.
On long-term follow-up of patients with deteriorated motor function, 6 patients out of 9 improved (66%) as follows: in group A, 2 cases (case nos. 1 and 6) with partial deficit but independent showed improvement of motor power and showed no disability, and one patient did not improve (case no. 5). One patient (case no. 9) with complete disability improved and had partial deficit but independent, while the other case still the same (case no. 3). in group B: 3 patients (case nos. 2, 5, and 6) of 4 cases with complete disability showed improvement of motor power to be partial deficit but independent, while the fourth case (case no. 7) did not improve.
Among these 3 cases with permanent complete disability, the first case (case no. 5 in group A) was a 56-year-old male patient with right parasagittal meningioma presenting with seizures and headache with no preoperative motor deficit; on the next day of surgery, the patient developed deterioration of conscious level, GCS became 12, rapid deterioration of motor power (upper limb grade II, Lower limb grade I), CT brain revealed severe cerebral edema, and patient was subjected to aggressive medical therapy including barbiturate coma and ventilation. On the third day, consciousness improved; GCS became 14; on discharge, patient was fully conscious, but motor power was still the same; on long-term follow-up despite that motor power showed mild improvement, upper limb became grade III and lower limb became grade II; and patient was still considered having complete disability. In the other 2 patients (case no. 3 in group A and case no. 7 in group B), no postoperative radiological changes were found.