The nature, growth pattern and surgical methods of craniovital communicating meningioma are discussed. Methods The clinical data of 84 cases of cranio-orbital communicating meningioma were analyzed and summarized, and the symptoms, signs, growth pattern of the tumor, timing of surgery, surgical approach and surgical methods and postoperative comprehensive treatment were discussed in more detail. Results From 2001.1 to 2008.12, a total of 129 cases of cranio-orbital communicating tumors were treated surgically in our neurosurgery and orbital disease institute, including 84 cases of meningioma, accounting for 65.1% of cranio-orbital communicating tumors. There were 3 cases of malignant meningioma, accounting for 3.6% of meningiomas. There were 81 cases of total resection and 3 cases of sub-total resection, and the rate of total tumor resection was 96%. Conclusion The first treatment option for cranio-orbital communicating meningioma is total surgical resection. Postoperative comprehensive treatment such as radiotherapy and chemotherapy can reduce recurrence according to the patient’s condition.
Data and methods.
1, General: 24 male cases and 60 female cases, age 3-61 years, mean age 36 years.
2. Clinical manifestations: 65 cases with monocular protrusion and 36 cases with ocular swelling. There were 6 cases of monocular vision loss and 2 cases of monocular blindness.
3. Imaging data: Cranial MRI and orbital tomography CT scan were performed in all cases to determine the relationship between the tumor site and the involved surrounding tissues; MRI and CT can clearly diagnose, accurately locate, and provide the best surgical plan.
4. Surgical methods: The surgery was performed using the subfrontal epidural approach, supraorbital-pterygoid approach, modified pterygoid approach and frontotemporal-orbital-zygomatic approach, and the four approaches could basically resect several cranial-orbital communicating meningiomas according to different tumor locations.
Results.
In this group, 54 cases of cranial-orbital communicating meningiomas were resected by supraorbital-a pterygoid point approach, 16 cases by modified pterygoid point approach, 10 cases by inferior frontal epidural approach, and 4 cases by frontotemporal-orbital-zygomatic approach. There were 81 cases of total resection and 3 cases of subtotal resection, and the total tumor resection rate was 96%.
Discussion.
1. Craniovital communicating meningioma refers to intracranial and extracranial (intraorbital) tumor spreading and connecting together through natural cavernous canal or bone destruction and traffic with each other. This tumor has deep location, complex anatomical relationship, vascular and neural concentration, involves multidisciplinary fields, has high surgical risk, and is prone to surgical complications.
The orbit is closely adjacent to the anterior and middle fossa of the skull, and is connected to each other through the supraorbital fissure and optic nerve canal. This anatomical feature allows tumors occurring in both cranial cavity and orbit to invade another part through these cavity orifices or destroy the surrounding bone wall, forming a communicating tumor across cranial cavity and orbit. Craniocaudal communicating meningioma can be divided into craniogenic and orbital types according to their origin. The orbital type first grows intraorbital, and as the tumor grows in size, it spreads intracranially through the natural canal. The craniocaudal type is the first intracranial tumor and mostly reaches the orbit through bone destruction (mostly of the orbital apex and lateral orbital wall) and partially invades the orbit through the supraorbital fissure. In craniogenic meningioma, the tumor is larger and has a longer growth time. Surgery is more difficult and requires postoperative skull base reconstruction. In this regard, we believe that there are cranial-derived and orbital-derived types according to the growth site.
3.The communication channels of cranio-orbital communicating meningioma should be summarized in this paper as three. One is orbital-optic nerve canal-cranial channel, the other is orbital-supraorbital fissure-cranial channel, and the third is orbital-bone destruction-cranial channel. There are also reports of infraorbital fissure channels in the literature. In this paper, we believe that the infraorbital fissure is an extracranial channel, and generally the tumor should grow from the orbit to the pterygofrontal fossa through the infraorbital fissure, so this channel should not be a cranial channel. Therefore, this channel should not be a cranial channel. However, the clinical observation is that the intraorbital tumor reaches the intracranial area through the supraorbital fissure and reaches the extracranial area through the infraorbital fissure.
4. Timing of surgery
At present, there is a unanimous opinion on the treatment of this tumor that surgery is the first treatment option. After surgery, precise radiotherapy should be performed to consolidate the effect of surgery. Weitzel advocates early surgery for radical treatment; Mc Dermott believes that surgery is difficult to improve the course of this type of tumor except for relief of proptosis; therefore, Miller advocates observation if vision is still good and surgery after complete loss of vision; Alper advocates early radical treatment. Our group believes that early radical surgery should be preferred for this type of meningioma. The reason is that this type of tumor can cause severe symptoms regardless of intracranial or intraorbital invasion and progression. If the patient only has vision loss but not blindness, early surgery to remove the tumor may save the patient’s vision, otherwise blindness is inevitable. If the patient is already blind, surgery is inevitable. If the tumor is located in the skull, the consequences can be imagined if surgery is not performed as early as possible. From the viewpoint of meningioma progress, this type of tumor is usually not limited, but often involves the periphery, especially to the meningeal lamina diffusion and blood supply is often rich, bone often has proliferation and destruction delayed surgery, which can make future surgery more difficult and increase the chance of side injury.
5.Surgical approach
The inferior frontal epidural approach is often used for meningiomas deep in the orbit and the optic nerve canal. It is performed around the inner orifice of the optic nerve foramen in the skull, and the front should be close to the superior orbital rim, paying attention to protect the supraorbital nerve. Carefully separate the anterior skull base dura, expose the intracranial part of the tumor, microsurgical resection, use grinding drill, grind away the orbital roof of the tumor edge, preserve the orbital rim, expose the intraorbital tumor, open the upper wall and part of the lateral wall of the optic canal if necessary, in order to completely remove the tumor.
The supraorbital-pterygoid approach, i.e. pterygoid approach with orbital opening, is suitable for communicating tumors in the anterior middle cranial fossa and paracranial saddle. The skin flap and the frontotemporal bone flap, the outer edge of the bone flap should be exposed to expose the lateral fissure pool. Subsequently, the superior orbital rim is opened with an electric swing saw at both ends, the orbital apex, and down to 1 cm above the optic nerve foramen, and the bone plate is abraded and removed with an electric saw to expose the orbit. If the internal foramen of the optic canal is to be exposed, the remaining bone is ground away to reveal the internal segment of the optic canal. This procedure does not require anterior skull base allograft reconstruction, and postoperative repositioning and fixation of the orbital apex is sufficient.
The incision is made from the superior edge of the zygomatic arch, upward to near the temporal line and then curved forward, and incised within the hairline to 2 cm contralateral to the midline. Care was taken to preserve the intact periosteum. To the anterior 1/4 of the temporalis muscle, the temporalis fascia and periosteum were routinely incised, separated to the superior orbital rim and lateral orbital rim, and the frontotemporal bone flap was taken to expose the frontal and temporal floor, and the pterygoid crest was precisely and meticulously occluded or abraded with a drill to fully expose the lateral orbital wall, the large wing of the pterygoid bone, the superior orbital fissure, and the anterior bed process. The dura mater is opened, the arachnoid at the lateral fissure pool or the frontal base brain pool is incised, the cerebrospinal fluid is released, the intracranial part of the tumor is removed internally and externally by the dura mater, and then the 2 cm wide lateral orbital wall bone is removed under the frontal zygomatic process with an electric swing saw or wire saw to expand and open the supraorbital fissure and expose the communicating tumor via the supraorbital fissure.
The frontotemporo-orbital-zygomatic approach The incision starts 1 cm below the zygomatic arch, crosses the backbend of the zygomatic arch, makes a coronal flap, and exposes the zygomatic arch, zygomatic prominence, and orbital rim under the periosteum. The drilling position is the same as the supraorbital-pterygoid point approach, and the zygomatic bone at the infraorbital lateral angle and the zygomatic arch in front of the mandibular joint are severed with a chainsaw. After protecting the dura mater, a saw was made at the junction of the inner 1/3 and 2/3 of the superior orbital rim, deep to the orbital apex. The broken end of the orbital apex is attached to the lateral wall of the orbit with a bone gouge, the bone flap is lifted and broken at the crest of the pterygoid bone, and the rest of the orbital apex can be occluded to expose the orbit. The pterygoid crest and part of the temporal scales were then removed by biting forceps.
6.Surgical points
① Separation of the temporal muscle is done by cutting the deep temporal fascia and periosteum at the zygomatic eminence and separating downward to the zygomatic arch to fully expose the lateral orbital wall and temporal bone, which is necessary for the excision of possible bone degeneration. For the temporal muscle fascia under the thick vein as much as possible to protect, its separation and protection for the postoperative local muscle tissue swelling subsided, swelling of orbital contents, the recovery of orbital protrusion, the prevention of subcutaneous fluid, a small amount of cerebrospinal fluid leakage has an important role in the treatment.
② Removal of the pterygoid crest The removal of the pterygoid crest is an important part, if not the key, to the success of the pterygoid point approach. This is especially true in cases where the bone destruction is more invasive. The usual maneuver is to occlude or grind out the entirety of the bony invasion and destruction of the pterygoid crest. In cranial-orbital communicating tumors with localized multiple cranial degeneration, supraorbital fissure deformation, and close relationship between tumor and skull with donor branches, for the consideration of long-term effect of surgery, the pterygoid crest should be removed patiently and carefully until the root of pterygoid crest, fully exposing the anterior temporal pole area, supraorbital fissure, and anterior bed prominence. ③ Operation of supraorbital fissure After partial resection of the intracranial tumor, part of the stump should be preserved at the inner orbital fissure, and the supraorbital fissure should be carefully ground open to separate the tumor, suture the fixation line, and facilitate the judgment and resection of the intraorbital tumor. The operation here should be performed with less electrocautery to prevent damage to the intraorbital neurovascular. When excising the anterior bed process of the medial superior orbital fissure, if the degeneration is obvious and abnormally thickened, pay attention to intermittent pauses and constant dripping of water to cool down the tumor when using the grinding drill to avoid side injuries caused by heat conduction of the medial optic nerve and internal carotid artery.
Application of a small bone window in the lateral orbital wall The orbital contents can be separated from the orbital plate gap under the frontal zygomatic process by the orbital periosteum, and the triangular lateral orbital wall with the bottom edge of the lateral orbital rim, about 2 cm long and the tip located at the superior orbital fissure, can be carefully removed with an electric pendulum saw or wire saw. If there is skull erosion or cranial defect, it is simpler to introduce the wire saw directly and saw off the bone fragment. The remaining cranial bone is then removed at the superior orbital fissure to connect the cranial orbit. In the case of cranio-orbital communication type, the intraorbital segment tumor is mostly shuttle-shaped or spherical. In this case, the marker line can be used as a guide to open the orbital fascia from the bone window area under the microscope and remove the tumor completely.
⑤ Tumor resection: Basically, the intracranial tumor is removed first, and then the orbit is opened to remove the intraorbital tumor. Generally, the dura is opened, the subarachnoid cerebrospinal fluid is released, the tumor is exposed, and the tumor is resected in pieces, paying attention to the protection of peripheral nerves and blood vessels. Most common nerves: optic nerve, olfactory nerve, ophthalmic nerve, trigeminal nerve. Most common blood vessels: internal carotid artery, middle cerebral artery, anterior artery, posterior communicating artery, ophthalmic artery, etc. When resecting intraorbital tumors, attention should be paid to the protection of the ocular muscles, and the muscles should be separated in the direction of the muscle fibers and not transected to avoid postoperative restriction of eye movement.
(6) After tumor resection, the lateral orbital wall was repositioned and fixed in situ with titanium nails and soft titanium plates for satisfactory appearance. At the same time, 0.5 cm of tipped temporalis muscle was separated at the anterior edge of the temporalis muscle under the temporalis fascia, extruded into a membrane, and attached to the bony defect. An artificial dura was placed over the meningeal defect for repair.