Surgery is generally the preferred treatment for pituitary adenomas. Guiot (1973) reported that among 563 pituitary adenomas operated by him, only 28% of patients were absolutely suitable for the transcranial approach and 10.5% were absolutely suitable for the transcranial approach, while the remaining 61.5% of patients could achieve satisfactory results with either of the two approaches.
In recent years, with the development of micro-neurosurgery technology, the safety and accuracy of transcranial surgery have been greatly improved. Under direct cranial view, the relationship between the upper pole of the tumor and the optic nerve, internal carotid artery and pituitary stalk can be clearly exposed, thus helping to protect the above mentioned structures, and more tumors growing to the saddle can be removed. In clinical practice, the transsphenoidal approach is more often used, while the transcranial approach is used when the tumor grows outside the saddle.
1.Transpalpebral approach: The transpalpebral approach was first applied to human body by Schloffer in 1907, and Cushing successfully applied the transpalpebral pituitary adenoma approach to treat a patient with acromegaly in 1909. In addition, the application of the surgical microscope has made the transsphenoidal approach a routine clinical approach for the removal of pituitary adenomas, including the sublabial – nasal diaphragm – pterygoid sinus, transnasal vestibule – nasal septum – pterygoid sinus and transseptal sinus – sinus pterygoid, etc. The first two are more commonly used, while the latter is less used except in a few hospitals. The surgery can not only selectively remove pituitary adenomas, but also preserve normal pituitary tissue, so that many patients with secretory adenomas can restore normal endocrine function after surgery.
Advantages: less trauma, high resection rate, less bleeding, no blood transfusion required for surgery, quick recovery, less pain, shorter hospital stay, no impact on nasal and facial appearance, and no concern for aesthetics.
Indications for the transsphenoidal approach.
①All pituitary microadenomas;
②Intrasellar pituitary macroadenoma, or mild suprasellar growth;
③Tumor growth towards the pterygoid sinus;
④pituitary tumor with cerebrospinal fluid nasal leakage; pituitary stroke without intracranial hemorrhage or subpituitary hemorrhage;
(⑤) Those with anterior fixation of the optic cross;
⑥Patients who are too old and frail to tolerate craniotomy;
(7) Large PRL and GH adenomas that have shrunk to the saddle after oral administration of bromocriptine.
Contraindications are.
(1) The pituitary gland extends to the saddle and has an irregular shape;
②Most of the tumor is located in the suprasellar region;
③Pterygoid sinus is poorly pneumatized or the juvenile pterygoid sinus has not yet developed;
④ Inflammation in the paranasal sinuses and nasal cavity. Nowadays, as long as the operation is appropriate, most of the patients can be operated by transsphenoidal surgery.
2.Transcranial surgery: The transcranial approach was first used by Krause in 1905, and it is suitable for larger pituitary adenomas growing to the suprasellar or extrasellar area, with symptoms of pressure on the optic nerve and other nerve tissues. The purpose of surgery is to release the compression of the tumor tissue on the optic nerve and optic cross to save the patient’s vision, and to release the compression on other tissues. Most of the symptoms of hypopituitarism cannot be improved. According to the size of the tumor, the direction of growth and the relationship with the surrounding nerves and tissues, transfrontal, trans-temporal or trans-pterygoid approach can be chosen.
Indications for surgery.
①Tumor grows to the saddle in a dumbbell shape;
②Tumor grows into the third ventricle, accompanied by hydrocephalus and increased intracranial pressure;
③Tumor growth outside the saddle to the anterior, middle and posterior fossa of the skull;
④Patients with nasal and paranasal sinusitis or poor pneumatization of the pterygoid sinus and no microscopic electric drill;
(⑤) unsatisfactory effect of radiotherapy;
(6) Those with intra-tumor hemorrhage with intracranial hemorrhage or subarachnoid hemorrhage.
Postoperative visual acuity and visual field recovery are influenced by the following factors.
①The degree of damage to the optic nerve before surgery, if it has been severely damaged before surgery, the postoperative recovery is poor;
②The time and degree of optic nerve compression, generally within one year the effect is better, more than two years recovery is very difficult;
③The degree of optic nerve atrophy.
Factors affecting the total resection of tumor.
①Tumor development stage and size;
②Tumor texture: most of the tumors are soft and easy to be removed during surgery, very few of them are hard and difficult to be excised, and some of them can be fibrotic and not easy to be excised if they take bromocriptine for a long time before surgery;
③Tumors with large size and invasion of dura mater;
④Pituitary adenoma does not have envelope, sometimes there is no boundary between tumor and normal pituitary tissue, and tumor cells can grow into pituitary tissue.
Postoperative complications: cerebrospinal fluid rhinorrhea, meningitis, uveitis, complications after cavernous sinus, internal carotid artery and cranial nerve injury, hypopituitarism, pterygoid sinus and nasal complications, nasal septal perforation, hypothalamic damage, optic nerve damage, intersaddle hematoma, pituitary crisis, epilepsy, psychiatric symptoms, delayed hyponatremia, hyperosmolar nonketotic diabetic coma, etc. GH adenoma can be complicated by thyroid crisis, acute heart failure, stroke, etc. Acute heart failure, stroke, etc.
Endoscopy in pituitary adenoma resection: Transendoscopic pituitary adenoma resection is a surgical procedure developed and applied in recent years. Through the neuroendoscope, structures that cannot be observed by the general operating microscope can be discovered. It allows the operator to see the panoramic view of the pterygoid sinus and avoid damage to the surrounding structures. And with improved illumination and magnification equipment, it can provide an excellent view of the pterygoid saddle and supra-saddle area. More importantly, the use of endoscopy allows the microsurgery to be expanded to allow visualization of posterior and peripheral structures, providing a good prospect for complete removal of the tumor and preservation of pituitary function to avoid neurovascular injury.
This is a safe and effective surgical approach in neurosurgery, avoiding the traditional incisional approach and postoperative nasal tamponade, and allowing patients to heal more quickly. However, the endoscope itself is coarse in diameter, the field of view is still too narrow, and the ability to change angles is poor, which is still a problem that needs to be solved. Moreover, the accumulated surgical experience is not too much, and the number of treated patients is relatively small, so it is necessary to do continuous and in-depth research.