Treatment of meningiomas of the skull base in children

Treatment of meningiomas of the skull base in children. How to treat meningiomas of the skull base in children? How to choose surgical approach in different positions?

Summary of treatment of meningiomas of the skull base in children

Pediatric skull base meningioma presents a series of unique challenges, not just its relative rareness in pathology and anatomy. Disease recurrence is particularly relevant in this age group; a giant anterior skull base meningioma, followed up for 10 years, is shown in Figures 1 and 2. Meningioma is more common in adults than in children.

Meningiomas in children account for less than 5% of all brain tumors in children and less than 2% of all meningiomas. A large modern case series found only 29 pediatric cases among 1737 meningiomas. Four This study and other studies show that childhood meningiomas are more likely to be atypical or malignant.

However, a recent clinicopathological analysis of 87 pediatric cases using revised World Health Organization standards found that 71% of WHO primary tumors, 24% of WHO secondary tumors, and 5% of WHO tertiary tumors The distribution of tumors is more similar to that of adult meningiomas previously reported. Meningiomas in children are thought to be more likely to be related to genetic diseases, such as neurofibromatosis type 2 (NF-2), Goring syndrome, or Rubinstein-Tabby syndrome.

The study found that compared with older children, these tumors are more likely to occur in the axis, and less likely to occur in the ventricle or in the posterior fossa. Meningiomas in older children are more likely to occur in the ventricles of the brain than in adults. Although very rare in children, meningiomas of the spine are mainly seen in women (83%), as are adults.

Similar to the performance in meningioma patients, the pediatric age group constitutes a small number of patients with skull base pathology. A recent single-institution case series included 223 adult and pediatric patients who underwent skull base surgery due to tumors or cerebrovascular diseases. It was found that only 27 of the 223 patients were younger than 18 years old. However, the therapeutic and cosmetic effects of multiple series of skull base approaches in this age group are very satisfactory. Although other factors of skull development must be considered when planning surgery, the benefits that pediatric patients get from minimal brain retraction are comparable to adults.

Much of the understanding of the behavior of meningiomas at the base of the skull in children has been generalized from adult data. Abstract A retrospective study of 227 adult patients with skull base meningioma found that advanced age is a risk factor for hydrocephalus after surgery. It is not yet known whether this age-related trend can be pushed back, or how far it can be pushed. Complications of hydrocephalus after meningioma surgery are rarely reported in pediatrics.

The surgical approach of the pediatric skull base

Many skull base approaches in neurosurgery have borrowed from techniques originally developed in pediatric craniofacial surgery, so they are very suitable for pathologies such as childhood meningiomas. From an epidemiological point of view, there are generally fewer skull base injuries in children than adults. Compared with adults, children have a higher rate of complete resection at the first surgery, which is attributed to a better definition of tissue plane and a higher incidence of benign tumors. However, due to blood loss, the potential need for staged surgery is greater in children.

Several general anatomical considerations have been observed. Children’s wing points are shifted forward relative to adults, which means that a standard keyhole burr will enter the periorbital rather than the anterior fossa. This trap can be avoided by placing piercing holes 2 cm behind the wing point. The frontal sinus of young children is often not ventilated, and the bone folds in the middle and middle fossa are often less. The most common postoperative complications are parasellar lesions (such as craniopharyngiomas), in which pituitary and hypothalamus injuries can occur temporarily or permanently.

Reports of preoperative embolization of meningiomas in children are rare. In 2013, 8 pediatric patients receiving tumor embolization treatment, including a 16-year-old patient with meningioma, successfully embolized a ventricular tumor before surgical resection. Very young children may face technical challenges with regard to the size of the intravascular catheter and the maximum tolerable contrast agent dose suitable for all intravascular procedures. Anterior skull base tumors with primary blood supply from the ethmoidal artery may not be suitable for embolization. Hemangioblastoma and choroid plexus tumors are the most common embolisms of intracranial tumors in children.

Precautions for anterior skull base surgery

In addition to the immature development of the frontal air sinus, the supraorbital foramen/notch is missing in children under 8 years of age. If possible, le Fort I osteotomy should be postponed until permanent teeth erupt. If necessary, the osteotomy is best placed at least 7-10mm above the root of the permanent tooth; many researchers have emphasized the importance of electroplating before hypospadias. Orbital zygomatic craniotomy is considered to be particularly advantageous in the removal of craniopharyngiomas, especially in fully exposing the upper third ventricle through the endplate or below the A1 segment of the anterior cerebral artery. Patients <3 years of age have also been observed to have a relatively less prominent sphenoid wing and flat middle fossa, resulting in less additional bone drilling once the orbitozygomatic complex is removed.

Both the transsphenoidal approach and the endoscopic approach are suitable for pediatric patients, but it should be noted that they are described in detail in the recent 25 and 133 clinical reports. Advantages include avoiding the development of dentition and facial growth plates, which is different from the traditional transfacial approach. However, gasification of the sphenoid sinus is rarely suitable for surgical approaches before about 3 years of age. A complete endoscopic transnasal approach is less traumatic to the nasal cavity than an endoscope; alternatively, a sublip incision can also be used. The full endoscopic approach is particularly useful for accessing the ventral anatomy of the skull base, such as the slope and foramen magnum. Other advantages of these methods are not aimed at children, including better protection of the optic nerve and pituitary gland, preservation of the sense of smell, and avoiding brain contractions.

Related reading: Can brain tumor patients who are afraid of craniotomy also have minimally invasive surgery? What are the indications for neuroendoscopic surgery?

Precautions for lateral skull base surgery

There are many surgical approaches to the skull base in children, including frontotemporal craniotomy, orbital and/or zygomatic osteotomy. Time craniotomy and zygomatic osteotomy and/or anterior petrosectomy have also reported similar results. Although the preauricular subtemporal approach has been described, the effect of mandibular resection in children is not fully understood. It is recommended to avoid mandibular resection or disconnection at this age. The transsphenoidal approach is also used to enter the middle skull base.

The role of posterior petrosal approach in pediatric skull base surgery was studied in detail. This approach is very versatile for pathology involving the middle and posterior fossa, and can be combined with the supratentorial approach for wider exposure. It preserves hearing and facial nerve functions and key venous structures, including transverse and sigmoid sinuses and labial veins. The distance between the sigmoid sinus and the primary labyrinth in children. In the case of incomplete mastoid development and insufficient ventilation, there may be insufficient window. In these cases, the medial approach can be enlarged through the opening of the dura mater after the sigmoid sinus. If the hearing is not affected, the medial approach can be enlarged through the translabyrinth or transcochlear approach. Close examination of preoperative magnetic resonance and computed tomography is the center to plan appropriately in these cases.

Precautions for posterior skull base surgery

Immature ventilation of mastoid air cells is the main problem of surgical access to the skull base. The strong bones make it more difficult to drill and identify the labyrinth, although the resulting exposure is described as requiring fewer nerve structures to contract than adults. Other approaches for children include the retrosigmoid approach, translabyrinth approach, transcochlear approach, transcondylar approach, and transjugular approach. The transcochlear approach requires facial nerve transfer. Compared with the retrosigmoid approach or translabyrinth approach, the risk of facial nerve transfer is higher. The sublabyrinthous subcochlear approach for the treatment of petroapical granuloma successfully reduced the patient’s symptoms while preserving hearing. The consideration of optimizing surgical approach based on pathological anatomy is similar to that of adults.

Conclusion

Skull base meningioma is a small subgroup of intracranial tumor pathology in children and requires extensive and specialized institutions for optimal treatment. In this patient group, the longer survival period makes the problem of disease recurrence particularly important. There is a broad consensus in the literature that patients of all ages who have undergone initial total resection have better progression-free survival and overall survival than patients with initial total resection. Expertise in skull base surgery methods and immature skull development is essential to optimize treatment outcomes. A multidisciplinary team of multi-surgeons may provide the best opportunity to achieve this integration.

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