Lesions in the paramedian region and interpeduncular fossa, including meningiomas of the medial pterygoid crest of the triple ventricle, meningiomas of the rocky oblique region, trigeminal nerve sheath aneurysms, and basilar artery tip aneurysms, are difficult to access to achieve a complete operation. In order to achieve perfect exposure and safe operation in these areas with the shortest possible distance and minimal brain tissue pulling, the authors devised a new surgical technique using the orbitozygomatic-inferior temporal approach. 16 cases of paramedian tumors, 9 cases of basilar artery tip aneurysms and 1 case of p-1 segment distal aneurysm were operated using the orbitozygomatic-inferior temporal approach with good results. The results were good. The authors describe this surgical technique and its results in detail. In 1977, we designed a new surgical approach, the orbitozygomatic-inferior temporal approach, consisting of a frontal-orbital-zygomatic-temporal craniotomy, abrasion of the posterior-lateral wall of the orbital bone and the lateral aspect of the foramen spinosum. most of the pterygoid crest. This approach provides adequate exposure of the infratemporal fossa, allows oblique superior access to the paracranial region and interpeduncular fossa, and allows safe access to the paracranial region and interpeduncular fossa by the shortest feasible route. Surgical Technique The patient is placed in the “park bench” position with the head tilted to the opposite side. Using a Mayfield three-peg head frame, the head is fixed at approximately 400 on the extension of the craniovertebral junction, with the neck tilted contralaterally to the lesion and the head tilted 350 down. the front of the operating bed is tilted upward so that the temporal region is essentially horizontal. To fully expose the zygomatic arch and the superior lateral wall of the orbit, a bilateral coronal scalp incision is made, starting at the inferior edge of the earlobe, along the anterior edge of the ear cartilage and extending upward and forward, including the hairline, to the level of 2 cm above the superior edge of the contralateral zygomatic arch. The superficial temporal fascia was separated by the temporalis muscle, and the frontal periosteum, 2 cm above the superior orbital rim, was turned forward along with the flap. To protect the temporal and zygomatic branches of the facial nerve, the fascia covering the temporomandibular joint capsule was carefully separated and the periosteum covering the external surface of the zygomatic arch was peeled vertically in front of the mandibular articular eminence, and the external surface of the zygomatic arch was revealed intact under the periosteum. Next, the superior lateral wall of the orbit is exposed, maintaining the continuity of the periosteum and the periorbital area. The superior lateral wall of the periorbit is separated from the posterior wall of the superior lateral orbit. The supraorbital foramen is opened with a pneumatic drill and gouge, from which the supraorbital nerve is freed and protected, and the periorbital perimeter is protected with a periosteal pusher. Four holes are drilled: the first hole is located lateral to the frontal bone behind the zygomatic frontal eminence, the second hole is located above the root of the zygomatic eminence of the temporal bone, the third hole is located 5 cm above the zygomatic arch on the coronal suture, and the fourth hole is located 5 cm above the supraorbital rim on the frontal bone. The posterior part of the zygomatic arch was incised with a sagittal saw, before the second and third foramina, the third and fourth foramina, and the fourth foramina and the medial aspect of the superior orbital rim were sawed with a craniotome. The orbital apex and lateral wall were incised with a sagittal saw and a thin 5-mm-wide chisel, with periosteal pushers to protect the periorbital area and a Penfield stripper to protect the dura of the orbital apex; to incise the orbital apex, a 5-mm-wide chisel was placed in the linear space at the anteromedial end of the craniotomy line at the superior orbital rim, and the medial aspect of the orbital apex was incised approximately 2 cm in the posterior lateral direction of the sagittal plane approximately 450 through the first foramen, with the chisel pointing with the superior The chisel was inserted through the first hole, pointing medially to the point where the cut line of the medial orbital apex met; in order to cut the lateral orbital wall, the chisel was inserted through the first hole and pointed vertically below the superior orbital fissure. From the superior lateral orbital fissure obliquely posterior to the superior lateral orbital gyrus, the zygomatic bone is incised using a sagittal saw. The first and second foramina are partially joined with a craniotome in order to disconnect the skull in this area. The frontal-orbital zygomatic-temporal bone flap is suspended over the posteriorly superiorly retracted temporalis muscle. The periorbital area and dura are protected with an automatic retractor with a reduced Sugita cerebral pressure plate at one end, and using a sagittal saw and small chisel, most of the remaining pterygoid crest that forms the lateral posterior wall of the orbit and the lateral part of the anterolateral portion of the sphenoid foramen of the middle cranial fossa is incised, and the posterior part of the orbital roof lateral to the superior orbital fissure is incised. The medial aspect of the remaining pterygoid winglets was partially abraded with a pneumatic drill. The dura was opened semicircularly from the medial aspect of the superior orbital rim toward the superior temporal region proper in the middle. The anterior edge of the dura is tractioned and the orbital contents are pressed inward and downward. Nowadays, using the surgical microscope, both a trans-lateral fissure approach and an inferior temporal approach can be used with minimal strain on the brain tissue. With the trans-lateral fissure approach, the lateral fissure is opened widely to protect the pontine vein originating from the top of the temporal lobe. The operator stands in front of the patient’s head, and by using the space created by both of these approaches, it is possible to reach the parasternal region and the interpeduncular fossa in a very short distance. In basilar artery tip aneurysm surgery, a trans-lateral fissure approach is often used in combination. The hook gyrus is gently retracted posteriorly, the cerebral gyrus located between the end of the internal carotid artery and the proximal middle cerebral artery is retracted upward, and the Liliquist membrane medial to the posteriorly inferiorly displaced arteriolar nerve is opened; this allows the interpeduncular fossa to be reached obliquely from below at the shortest possible distance. With this exposure, the basilar artery and its bifurcation can be adapted to the operator, being obliquely visible from below, and the p-1 segment and p-1 segment penetrating branches on the left and right sides can be clearly seen. Using this pathway, bifurcation aneurysms in both lobes and lesions all in the posterior interpeduncular fossa can be reached. At the time of cranial closure, a nylon thread was used to penetrate the separated majority of the pterygoid crest, superior orbital wall, and posterior lateral orbital wall through a small drilled out hole. Case summary Since 1977, we have used this approach, combined with the trans-lateral fissure and inferior temporal approach, to operate on 7 cases of medial pterygoid crest meningioma of the triple ventricle, 4 cases of chordoma of the rock oblique region, 3 cases of dumbbell-shaped trigeminal nerve sheath aneurysm, 1 case of rock oblique region meningioma, 1 case of glioma originating from the hook gyrus, 9 cases of basilar artery tip aneurysm, and 1 case of p-1 segment terminal aneurysm All cases recovered well. All cases recovered well and returned to work after surgery. We will focus on describing a representative case. The case was a 42-year-old male with a right-handed lee and a giant left medial pterygoid crest meningioma of the third ventricle, which was operated using a left orbitozygomatic-inferior temporal approach combined with a trans-lateral fissure approach. The tumor encircled the left internal carotid artery, the left middle cerebral artery and the proximal superior cerebral artery, as well as the posterior communicating artery and the anterior choroidal artery, with the top of the tumor extending into the elevated interpeduncular fossa. The left optic nerve was elongated, flattened, and significantly displaced inward and forward, and the left actinic nerve was significantly elongated and displaced downward. We removed the tumor completely and protected all the encapsulated vessels and displaced nerves. The patient had mild postoperative motor aphasia that lasted for one week, followed by left-sided motoneurysmal nerve palsy over the next two months, and neurological resolution at three months. Discussion Complete resection of the parsaddle tumor and direct clamping of the basilar artery tip aneurysm during surgery is always difficult. The operative distance to reach the parsaddle region and the lesion in the interpeduncular fossa using the orbitozygomatic-inferior temporal approach is 3 cm shorter and 1 to 2 cm lower in angle than using the pterygoid point or inferior temporal approach. Compared with the conventional surgical approach, even for large tumors, such as meningiomas of the medial pterygoid crest of the three ventricles, meningiomas of the rocky oblique region, and aneurysms of the tip of the basilar artery, this surgical approach, which operates on the parsaddle region and important structures in the interpeduncular fossa are much easier and safer. In such a low level craniotomy, it is necessary to know the facial anatomy in order to protect the peripheral facial nerve. After exiting the stem mammary foramen, the main trunk of the facial nerve intersects the posterior border of the mandible 2 cm below the earlobe and then enters the parotid gland from behind, between the surface and the deep part of the gland. The facial nerve branches leave the gland superiorly, anteriorly and inferiorly to form multiple branches located on the surface of the Bichat fat and enter the facial muscle inferiorly from the deep surface of the facial muscle. The temporal and zygomatic branches intersect the zygomatic arch 2 cm above the superior edge of the external auditory canal; therefore, it is safe to cut the skin along the anterior edge of the earlobe. Together with the skin flap, the superficial temporal fascia is lifted and the zygomatic arch and zygomatic bone are protected by subperiosteal separation of the temporal and zygomatic branches of the ipsilateral facial nerve. Conclusions We propose and evaluate an orbitozygomatic-inferior temporal approach to the paracranial region and the interpeduncular fossa. We acknowledge the good results achieved by Drake using the inferior temporal approach and Yasargil et al, using the pterygoid point approach, and do not believe that the orbitozygomatic-inferior temporal approach provides better anatomic access to the lesions located in the paracranial region and the interpeduncular fossa. and their surrounding structures. However, we believe that this procedure is technically more necessary because, in addition to microsurgical techniques, familiarity with the use of chisels and sagittal saws is essential for the completion of the procedure. The number of cases operated through this approach, in terms of patient mortality and disability, is not sufficient to determine whether this approach has clear advantages over the conventional surgical approach, but we are encouraged by the results of this group of cases.