(i) Transsphenoidal approach for pituitary tumor resection Since its first use by Schloffer in 1907, there have been several variations of the transsphenoidal approach, such as the oronasal pterygoid approach, the single nostril pterygoid approach, the septal pterygoid approach, and the maxillary pterygoid approach. At present, the single nostril pterygoid approach is the most used.
1, sublabial transnasal septal approach through the pterygoid sinus This approach has long been widely used by domestic and foreign neurosurgeons, less traumatic than craniotomy, was a safe and effective surgical method. It is more complicated than the single nostril approach, and the septum stripping is more troublesome, and there is a certain incidence of septal perforation.
2. Single nostril submucosal transosseous septal approach The approach is gradually developed in recent years, because the bony septum and mucosa are easily separated, the operation is convenient and time-saving, and the mucosa of the contralateral septum will not be broken, so there is generally no sequelae of septal perforation; the steps at the end of the operation are also simpler and the operation time will be significantly shortened.
3. Single nostril septum push through the anterior wall of the pterygoid sinus The advantage of this approach is that the septum does not need to be stripped and the pterygoid sinus is entered directly, which is more time-saving compared with the aforementioned approach. For the recurrence of the transsphenoidal approach, it is better to use this approach.
4. Transsphenoidal sinus endoscopic surgery As the septum and turbinates are not affected by this surgery, the trauma is minimal and the patient has almost no nasal discomfort after the surgery, this surgical method will become mainstream as time goes by.
(1) Indications and contraindications for transsphenoidal approach surgery: ①Indications: various types of pituitary microadenoma; various types of intra-saddle pituitary macroadenoma; various types of pituitary giant adenoma with the main direction extending to the saddle and symmetrical growth in the saddle. (ii) Contraindications: nasal inflammation, such as pterygoid sinusitis, rhinitis, etc.; pituitary giant adenoma with obvious lateral growth; those who develop toward the frontal floor and posterior saddle; those who have general contraindications to surgery, such as coagulation mechanism disorders, serious cardiopulmonary disorders.
(ii) Surgical procedure 1. Pre-operative preparation: ① Clear diagnosis, relevant endocrinological examination, visual acuity, visual field and fundus examination, pterygoid saddle plain film to understand pterygoid sinus pneumatization, MRI plain scan intensification scan to understand tumor size, growth characteristics and relationship with surrounding structures. ②Nasal preparation: antibiotic nasal drops 3 days before surgery and nasal hair clipping one day before surgery. (3) Pituitary preparation: apply cortisol or thyroxine 3 days before surgery.
2.Anesthesia: general anesthesia by endotracheal tube.
3.Position Supine position, head elevated 15°-20°, slightly to the left, so that the nostrils are aligned with the surgeon.
4.Surgical procedure (1) Nasal disinfection, iodophor cotton gauze repeatedly disinfected in the nasal cavity several times. Brain cotton infiltrated with epinephrine saline (one epinephrine is added to 500ml NS) is filled and infiltrated with the submucosa layer under the nasal columella and both sides of the nasal septum of both nostrils for about 1 minute to facilitate hemostasis and the peeling of the mucosal layer.
(3) A nasal opener was placed, aligned with the deep upper and middle turbinates, and gently propped open to separate the nasal mucosa on both sides of the septum up to the anterior wall of the butterfly sinus. Push the septal cartilage with mucosa to one side. Readjust the speculum to the anterior wall of the pterygoid sinus. At this point, the openings on both sides of the pterygoid sinus can be seen. The anterior wall of the pterygoid sinus is resected with a bone drill or chisel and a biting forceps, and the bony partition in the pterygoid sinus is removed, peeling away as much mucosa as possible. Carefully identify the saddle base and remove the saddle base bone, paying attention not to injure the internal carotid artery next to the two sides.
(4) The dural cross incision will reveal the grayish white tumor tissue herniated from the dural incision. After removing enough pathological tissues with tumor removal forceps, the tumor will be removed by suction first, and then scraped with a scraping spoon. After resection of tumor in the saddle, the soft tumor in the saddle can descend into the saddle by itself.
(5) After the tumor is completely scraped out, the saddle diaphragm will no longer bleed and descend into the saddle and stick to the saddle base.
(6) Remove the spreader, reset the nasal septal cartilage, and fill the nostrils on both sides with Vaseline gauze. Remove it after about 48 hours.
(7) Neuroendoscopic-assisted surgical treatment is one of the effective means for total resection of tumor.
(5) Postoperative treatment (1) Routine anti-infection for 3-5 days, and can be extended appropriately for those with cerebrospinal fluid leakage. (2) Supplementary glucocorticoid, generally with dexamethasone 10mg IV. (3) Nasal stuffing is removed after 24 to 48 hours. (4) For those with uremia, give double gram 50mg orally 3 times a day, also use posterior pituitary hormone or long-acting uremic stop to control urine volume, the duration of uremia usually does not exceed one week after treatment. (5) Individual patients may have a small amount of cerebrospinal fluid leakage, which can mostly heal on its own in about 1 week.
Transcranial approach is common: inferior frontal approach, pterygopoint approach. Transcranial approach is mainly operated through the crossed anterior hiatus in the area between the internal carotid arteries, and the structures such as internal carotid artery and optic nerve should be protected during the operation to reduce the occurrence of complications. The surgery is performed with a right inferior frontal approach, lifting the right frontal lobe and clipping the right olfactory nerve if necessary. The main limitation of the transfrontal approach to the pterygoid saddle area is the optic nerve and optic cross, especially when the optic cross is anterior type the surgical access is narrower. This approach is convenient and simple, with adequate exposure of the paracentral and suprasellar portions of the saddle, and the pituitary stalk, internal carotid artery, optic cross and optic nerve can be separated and protected under direct vision. However, this approach is very traumatic, with little visual field exposure and incomplete resection for tumors protruding into the saddle and into the hypothalamus. Especially for those who protrude into the hypothalamus and have obvious compression damage to the optic nerve and optic cross, the surgery emphasizes too much on total resection, which directly or indirectly causes hypothalamic damage or rapid loss of vision and risk of blindness, and normal pituitary function is also damaged. Although the endoscopic application can reduce the dead angle, if the tumor protrudes into the pterygoid sinus, it is still impossible to remove the intra-sinus part from the inferior frontal approach.
The pterygopoint approach is also called “interfascial pterygopoint craniotomy” or “frontotemporal pterygopoint approach”, which has the following advantages: ① the shortest surgical path, the largest field of view, full dissection of each brain pool in the saddle area, larger operation space, and the least strain on the brain tissue. The damage to the brain tissue is the least. It can protect the pituitary stalk, hypothalamus, optic nerve, optic cross, skull base arterial ring and its penetrating vessels under direct vision. ③No damage to the olfactory nerve. ④The incision is made in the hairline with little damage, and the postoperative appearance is mostly unaffected. ⑤ The size and position of the bone window are appropriately adjusted according to the size and growth pattern of the tumor, making full use of the four anatomical gaps in the saddle area. In the operation of trans-pterygoid approach, attention should be paid to protect the pituitary stalk, optic nerve, skull base artery, cavernous sinus and other important tissues, and the power of electrocoagulation should be as small as possible and the time should be short to avoid heat conduction damage to pituitary stalk, optic nerve and hypothalamus. The common complications of craniotomy: inferior optic thalamus injury, optic nerve injury, uveitis, intracranial hematoma, intracranial infection, cerebrospinal fluid leakage, etc.