Fig. 1
Cutaneous and bony landmarks for minipterional approach. The head is fixed in a three-point Mayfield head rest, rotated about 45°, and tilted to elevate the zygoma. The hairline is marked with a dashed line (dotted arrow), and the hair is shaved for about 1.5 cm. The superior temporal line is then marked (arrow) and the skin incision is performed along a semi-arcuate trajectory (arrowheads) starting 1 cm above the zygomatic arch and extended 1 cm above the linea temporalis superficialis (a). A single burr hole is made at the stephanion and MPT of about 5 cm is performed to expose the sylvian fissure (b). Before dural opening, the sphenoid ridge is drilled in order to enlarge the surgical corridor before the microsurgical dissection of the sylvian fissure (c). The MPT craniotomy flap is synthesized with three titanium plates (d)
Fig. 2
Volumetric three-dimensional (3D) rendering showing the size of MPT craniotomy after osteosynthesis with titanium plates (a). Esthetic result after MPT approach: no alterations in the morphological profile of the patient’s face are evident (b)
Statistical Analysis
Values for quantitative variables were expressed as mean ± standard deviation and compared with each other using Student’s t-test. Fisher’s exact (two-sided) test was used to compare the categorical variables with the outcome (univariate analysis). The association between variables was considered significant when the p value was <0.05.
Results
Demographic Features
The mean age of the patients was 56.6 ± 10.6 years in the PT group, and 58.8 ± 10 years in the MPT group (p = 0.38). There were 25 females and 12 males in the PT group, and 27 females and 4 males in the MPT group (p = 0.08).
Topographic Distribution and Angioarchitectural Features of MCA Aneurysms
Among the 37 patients treated with standard PT, 14 (37.83 %) had an aneurysm involving the left and 23 (62.16 %) the right MCA; 17 of them had multiple aneurysms. Twelve aneurysms (32.43 %) were located at the bifurcation of the left, and 23 (62.16 %) at the bifurcation of the right MCA, 1 (2.7 %) was located at the left M2 and 1 (2.7 %) at the left M3 segment (Fig. 3 upper). Among the 31 patients treated with MPT, 12 (38.70 %) had an aneurysm involving the left and 19 (61.29 %) the right MCA; 12 of them had multiple aneurysms. Twelve aneurysms (38.70 %) involved the left MCA bifurcation, 15 (48.38 %) the right MCA bifurcation, 3 (9.67 %) the right M1, and 1 (3.22 %) the right M2 segment (Fig. 3 lower). In the PT group there were 31 small, 5 large aneurysms and 1 giant one, whereas in the MPT group, there were 30 small aneurysms and 1 large one (Table 1). The topography of the aneurysms was not significantly different between the two groups. Larger aneurysms measured 35×18 mm, whereas the smaller ones measured 3×2 mm; the mean aneurysm size was 7 mm. The mean skin incision length was 14 cm in the PT group and 6 cm in the MPT group. During the procedures with MPT, instances of compromised operative corridors requiring craniotomy extension never occurred.
Fig. 3
Upper figure: topographic distribution of middle cerebral artery (MCA) aneurysm treated with standard pterional craniotomy (PT). Lower figure: topographic distribution of MCA aneurysms treated with minipterional craniotomy (MPT)
Table 1
Relationship between size and location of MCA aneurysms treated with standard PT and MPT
M1 segment | M1-M2bifurcation | M2 segment | M3 segment | |||||
|---|---|---|---|---|---|---|---|---|
PT | MPT | PT | MPT | PT | MPT | PT | MPT | |
Small | – | 2 R | 18 R 11 L | 14 R 12 L | – | 1 R | 1 L | – |
Large | – | 1 R | 4 R 1 L | 1 R | 1 L | – | – | – |
Giant | – | – | 1 R | – | – | – | – | – |
Clinical Outcomes
Clinical outcomes at discharge and follow-up were assessed by the GOS and mRS. The mean length of clinical follow-up was 37.3 ± 7.2 months for the PT group, and 20.9 ± 7 months in the MPT group. At discharge, 35 of the 37 patients (94.59 %) in the PT group showed GR, 1 (2.70 %) MD, and 1 (2.70 %) SD, while in the MPT group, 30 of the 31patients (96.77 %) had GR, and 1 (3.22 %), SD. These results were stable at follow-up. According to the mRS grading at discharge, in the PT group there were 31 patients (83.78 %) with 0 points, 4 (10.81 %) with 1 point, 1 (2.7 %) with 3 points, and 1 (2.7 %) with 4 points. At follow-up, 2 patients showed a further improvement in the quality of life, with disappearance of the previous minor symptoms, thus changing the score from 1 to 0 points. In the MPT group, in contrast, at discharge there were 28 patients (90.32 %) with 0 points, 2 (6.45 %) with 1 point, and 1 (3.22 %) with 4 points. At follow-up, all the 3 patients who previously complained of symptoms showed an improvement; two of them, in particular, showed complete restoration from perioperative seizures and wound healing. There was no significant difference in clinical outcomes between the two groups, either at discharge or at follow-up (Table 2).
Table 2
Clinical outcomes at discharge and follow-up for PT and MPT groups
