The aim of the project is to compare the effect of different extent of resection of the posterior part of the septum on the postoperative nasal functions.

The nasal cavity is used to heat, humidify and purify the air before entering other parts of the respiratory system. Other functions of the nose include in particular olfactory, immune, reflex or sexual functions.

Proper airflow through the nasal cavity is essential for all nasal functions; anatomical or flow changes can significantly affect nasal functions.

Endoscopic transnasal surgical approaches are modern, mini-invasive methods, enabling solution of pathologies in the area of the cranial base, through the nasal cavity. The advantage of this technique is absence of external incisions and scars and significantly better cosmetic effect, these methods also offer very good clarity and illumination of the operating field. Main disadvantage is risk of affecting functions of the nose.

To create a transnasal approach to skull base, it is necessary to perform lateralization of middle turbinates, resection of anterior wall of sphenoidal sinus and resection of posterior part of the nasal septum. These interventions are necessary for a good overview and manipulation in the operated area; however, they can lead to postoperative changes in the physiological functions of the nasal cavity, especially loss of smell, taste, altered airflow through the nasal cavity, mucociliary transport disorders, nasal obstruction, crusting or drying mucous membrane. All these adverse changes significantly affect patient's quality of life.

Larger extent of septal resection allows the surgeon to have a better overview and manoeuvrability in the operated area, which allows sufficient radicality and allows the solution of possible complications. On the other hand, greater resection also means greater interference with the anatomy of the nasal cavity and possible influence on nasal functions.

The aim of the project is to compare the effect of different extent of resection of the posterior part of the septum on the postoperative nasal functions.

Study design:

• all operations will be performed by the same operations team
• prior to surgery, patients will be randomly tossed into two groups according to the extent of resection of the posterior edge of the septum as part of the transsphenoidal approach during cranial base surgery
• group A - Patients will be resected with a posterior 1 cm nasal septum as part of a transsphenoidal approach.
• group B - Patients will be resected with a 2 cm posterior nasal septum as part of a transsphenoidal approach
• if the selected extent of resection is not sufficient during surgery for group A, it will be extended so that the lesion can be safely removed, and patient will be removed from study

Operational procedure:

1. Anemization of the nasal mucosa using strips with diluted adrenaline 1: 1000.

2. Endoscopy of the nasal cavity and identification of important anatomical structures.

3. Lateralization of the middle and upper turbinates, identification of the anterior wall of the sphenoidal sinus and its natural ostium.

4. Apply suction with a marked distance of 1 and 2 cm to the septum and mark the extent of laser resection on the septal mucosa.

   The suction is applied paraseptally to the anterior wall of the sphenoidal sinus at the height of the natural ostium (1.5 cm above the upper edge of the choana), the caudal border of the resection is the height of the upper edge of the choana, the cranial border is the ceiling of the sphenoid.

5. Resection of the septum in the given range.

6. Resection of the anterior wall of the sphenoidal sinus, resection of the intersphenoidal septum.

7. Rest of the operation is identical in both groups of patients (tumour resection, revision of the nasal cavity, nasal tamponade).

   • At preoperative examination and 1 month after surgery, patients will have:
   • endoscopy of the nasal cavity with Lund-Kennedy scoring system (evaluation of oedema, secretion, crust)
   • olfactory examination - test of identification and discrimination with perfumed markers
   • SNOT 22 questionnaire
   • RhinoVAS questionnaire
   • Nose score

Statistical evaluation:

• comparison of nasal functions after cranial base surgery in patients with a range of resection of the posterior edge of the septum 1 cm and 2 cm
• comparison of olfactory before and after surgery in both groups of patients

Inclusion Criteria:

• age over 18 years
• patients with functional pituitary adenoma indicating endoscopic transnasal extirpation of the pituitary adenoma

Exclusion Criteria:

• patients after surgery of the nasal cavity or base of the skull
• patients with nasal disease and PND
• patients with olfactory disorders before surgery
• patients with nasal septal deviation

There is no plan to make individual participant data available to other researchers. Individual participant data may be provided upon request.

No masking will be used in the study.