With the improvement of microscopic neurosurgery technology and the development of neuroimaging diagnostic technology, transsphenoidal sinus approach for pituitary tumor removal has been widely used in clinical practice, which is convenient, safe, less traumatic and has quick recovery. From April 2005 to June 2007, 23 cases of pituitary tumors were resected under the microscope through the single nostril pterygoid sinus approach with satisfactory results.
1. Clinical data
1.1 General data The 23 cases in this group, 8 males and 15 females, aged 17 to 75 years old, average 32 years old, had a disease duration of 3 months to 2 years, average 1O months. There were 18 cases of unilateral or bilateral vision loss with temporal visual field defects; 16 cases of endocrine dysfunction, including 10 cases of menstrual disorders and amenorrhea, 4 cases of acromegaly and 2 cases of decreased sexual function; 6 cases of headache and other manifestations of cranial hypertension. All patients underwent coronal CT scan and MRI examination of the saddle area to clarify the tumor size and invasion site. Hormonal and pathological examinations: 10 cases of PRL adenoma, 4 cases of GH adenoma, 2 cases of ACTH adenoma and 7 cases of non-functional adenoma.
1.2 Indications
(1) Pituitary microadenoma;
(2) Large pituitary adenoma, but the main body of the tumor is located in the saddle and invades into the pterygoid sinus;
(3) Large pituitary adenoma with the main body of the tumor located in the saddle and the suprasellar extension is not dumbbell-shaped, and the tumor does not extend to the parsellar area [1].
1.3 Contraindications
(1) Inflammation of the nasal cavity;
(2) Poor pneumatization of the pterygoid sinus;
(3) Dumbbell-shaped extension of the tumor into the suprasellar region;
(4) Tumor extension to the paracranial, posterior saddle or anterior cranial fossa.
(5) Small nostril or obvious anatomical abnormality in the nose with pterygoid sinusitis.
(6) The tumor diameter is greater than 5.0 cm.
(7) Imaging examination shows tumor with tough texture and rich blood flow.
(8) Those who have coagulation mechanism disorder or other serious diseases.
1.4 Surgical method
(1) Clean the nasal cavity.
(2) Select the access to the nasal cavity. For ease of operation, the right nasal cavity is usually chosen.
The tumor can be removed with a spatula, and the saddle base can be seen to be mildly depressed after resection.
(4) Under the microscope, pay attention to identify the tumor and pituitary tissue. For the tumor tissues protruding from the saddle, after resection in the saddle, increase the intracranial pressure appropriately to make the tumor tissues in the saddle collapse downward before full resection. Pay attention to not to damage the saddle diaphragm during the operation.
(5) Adequate hemostasis of the tumor bed. After resection of the tumor, the saddle should be filled with hemostatic gauze or gelatin sponge to stop the bleeding. To prevent cerebrospinal fluid leakage after surgery, the pterygoid sinus should be closed with gelatin sponge supplemented with medical biogel.
(6) The nasal septum cartilage and mucous membrane are reinstated and the nasal cavity is filled with an expanding hemostatic sponge to keep the posterior nostril open. This surgical approach does not need to strip the nasal mucosa, and the nasal dilator breaks the septum directly to reach the anterior wall of the pterygoid sinus, which simplifies the surgical steps and greatly reduces the probability of postoperative septal perforation.
1.5 Results All 23 patients had different degrees of recovery of symptoms after surgery. Of the 18 patients with decreased visual acuity, 12 cases returned to normal and 6 cases had improved visual acuity; 16 cases had endocrine dysfunction, 9 cases had restored menstruation, 1 case had improved sexual function, and 2 cases had reduced acromegaly. The hormone level was normalized in 13 cases and decreased in 3 cases. 3 months later, the MRI was reviewed and 20 cases were completely resected and 3 cases were mostly resected.
2. Discussion
2.1 Surgical methods and techniques
(1) Carefully read the MRI film before surgery to study the size of the pterygoid sinus, the morphology and degree of deviation of the separation, the position of the saddle base in the pterygoid sinus, and the spacing of the cavernous sinus segments of the internal carotid artery on both sides to ensure accurate intraoperative positioning.
(2) Master the midline: after inserting the dilator into the anterior wall of the pterygoid sinus to dilate it, the pterygoid crest must be found and placed in the middle of the operative field. However, in individual cases, due to the lack of bone in the anterior wall of the pterygoid sinus, the thinness or the excessive force of the operator in the expansion, the front end of the dilator oversteps the midline and arrives directly at the anterior wall of the contralateral cavernous sinus, which is treated as the anterior wall of the pterygoid sinus or the saddle base and chiseled away, and it is very easy to damage the internal carotid artery in the cavernous sinus. In large adenomas, especially in large adenomas, the bone is thin or destroyed, and when gently touched with a blunt instrument, there is a plunge or rupture, and the two are easier to distinguish.
(3) Preserve the mucosa of nasal septum without resection to avoid atrophy of nasal mucosa and perforation of nasal septum.
(4) When scraping the tumor, scrape the posterior and both sides first, if the anterior, it is easy to cause the saddle diaphragm to sink and cerebrospinal fluid to leak to affect the surgical effect.
(5) When removing tumor, use different caliber scrapers to scrape from shallow to deep, repeatedly scraping and advancing layer by layer to avoid side injuries caused by one-time scraping. If the tumor develops in the suprasellar direction and the degree of suprasellar part collapse is unsatisfactory during surgery, the anesthesia ventilator can be used to increase the intrathoracic pressure, thus increasing the intracranial pressure.
It helps to collapse the suprasellar part towards the saddle, and generally hold the breath for about 15 seconds.
(6) Intraoperative bleeding from intercavernous sinus injury should be avoided with electrocoagulation to stop bleeding, and gelatin sponge compression should be used to stop bleeding with obvious effect.
(7) The application of gelatin sponge and medical biogel to fill the saddle base by “sandwich” method has good effect.
In other words, after the surgery, the inner layer is filled with gelatin sponge dipped in medical biogel and the middle layer is filled with gelatin sponge, and the outer layer is filled with the same material and method as the inner layer. The advantage of this method is that the inner layer can adhere to the saddle base with biogel, which can prevent the leakage of cerebrospinal fluid, and also can prevent the saddle from being filled with the stuffing after the hardening of the gelatin sponge. The middle layer is slightly thicker and can be well swollen without biogel, thus facilitating intra-saddle hemostasis, while the outer layer plays a reinforcing role.
2.2 Advantages and disadvantages of surgery Advantages.
(1) Tumors with soft texture and not growing to both sides of the cavernous sinus can be completely removed, especially when removing microadenomas, and the possibility of damage to the pituitary stalk caused by the traditional inferior frontal approach can be avoided.
(2) Small side injury, the surgical path is short as it reaches the pterygoid sinus directly through the nostril, and the tumor can be removed by only bluntly separating part of the mucosa and opening the pterygoid sinus.
(3) No removal of the nasal columella reduces the surgical trauma, and it is not necessary to remove the inferior margin of the pyriform foramen and the anterior nasal spine, avoiding the injury of the superior alveolar nerve.
(4) Patients recover quickly after surgery and reduce the cost of surgical treatment. Patients do not need special preparation before surgery and no special treatment after surgery, and they can get out of bed and eat on the second day after surgery, or even get up and move around on the first day. The average hospitalization day of this group is 7 days, and the average hospitalization day is shortened by 3-4 days. (5) Less surgical bleeding; it reduces the traditional coronal incision via inferior frontal approach from 50 ml to 2 ml to 10 ml. Disadvantages.
(1) Tumor removal is unsatisfactory if the tumor is too large or bleeds raging intraoperatively or if the tumor is tough in texture.
(2) It is difficult to observe some anatomical structures that cannot be seen directly. (3) The surgical space is relatively small, and special surgical instruments are required.
(4) Compared with the transcranial approach, postoperative nasal leakage of cerebrospinal fluid is easy to occur.
In conclusion, microscopic transcranial pterygoid sinus approach is a safe and effective method to remove pituitary tumor. Due to the narrow operating space, the operator is required to have sufficient knowledge of the relevant anatomical structures and rich experience in microsurgery, and can correctly grasp the indications and contraindications for surgery to ensure the surgical results and timely and correct management of complications.