Comparison of Extent of Resection of Pituitary Adenoma Via Transnasal Transsphenoidal Approach Using Endoscope Versus Microscope

Pituitary adenomas were sellar tumors that could cause visual disturbances, neurological manifestations, and hormonal abnormalities. The need for surgical treatment depended on tumor characteristics, functional status, and clinical presentation. Transnasal transsphenoidal surgery was an established approach for pituitary adenoma resection and had traditionally been performed using an operating microscope. With advances in endoscopic equipment and skull-base surgical techniques, endoscopic transnasal transsphenoidal surgery had increasingly been adopted as an alternative approach. Endoscopy provided panoramic visualization, magnification, improved illumination, and the ability to use angled lenses to inspect areas that were difficult to visualize using a microscope. These technical features facilitated access to the sellar and parasellar regions and improved visualization of tumor components extending beyond the direct microscopic line of sight. Both approaches aimed to achieve maximal safe tumor removal while preserving normal pituitary tissue and surrounding neurovascular structures. Previous comparative studies reported differences in the extent of tumor resection and operative duration between endoscopic and microscopic approaches; however, reported resection rates varied across studies, indicating the need for further comparative evaluation. Therefore, this randomized controlled trial was conducted to compare the extent of pituitary adenoma resection achieved through endoscopic and microscopic transnasal transsphenoidal surgery. The study was conducted in the Department of Neurosurgery, Sir Ganga Ram Hospital, Lahore, Pakistan, from 04 December 2022 to 03 December 2023. A total of 38 patients were included, with 19 patients allocated to each group. The sample size was calculated using a 95% confidence level and 80% power of the test, taking the expected percentage of resection as 88% in the endoscopic group and 47.8% in the microscopic group. Patients aged 20-60 years of either gender who underwent transnasal transsphenoidal surgery for pituitary adenoma were included. Patients with prolactinomas unresponsive to medical treatment or causing mass effects were also eligible. Patients with recurrent pituitary tumors and those with pituitary tumors having suprasellar or parasellar extension were excluded. After approval from the hospital ethics committee and obtaining written informed consent, eligible patients were enrolled from the neurosurgery outpatient department. Patients were randomly allocated in a 1:1 ratio using random allocation software. The randomization sequence was concealed through sequentially numbered, sealed, opaque envelopes prepared by the investigator. Group A underwent endoscopic transnasal transsphenoidal surgery, while Group B underwent microscopic transnasal transsphenoidal surgery. Demographic information, including age and gender, was recorded on a structured proforma. Preoperative assessment included magnetic resonance imaging (MRI) of the brain using plain and pituitary-protocol imaging to determine tumor dimensions and volume. Hormonal assessment included thyroid function tests, serum cortisol, growth hormone, and serum prolactin levels. Perimetry and routine investigations required for general anesthesia were also performed. Surgery in both groups was performed by the same surgical team, including the principal investigator, to maintain consistency in the operative procedure. In Group A, sphenoidotomy was performed to visualize the tuberculum and clival recess, followed by identification of the bilateral optic carotid recesses. The mucosa over the sellar floor was removed, and the medial optic carotid recesses and medial margins of the cavernous sinus were exposed. An adequate sellar bony window was created, followed by dural opening. Extracapsular debulking of the adenoma was performed circumferentially, with internal decompression carried out in a piecemeal fashion. When the tumor surrounded the anterior surface of the internal carotid artery, a direct approach to the lateral component of the cavernous sinus was used. An angled endoscope was used for tumor removal from the cavernous sinus, and blind curettage was not performed. Tumor severely adherent to the internal carotid artery or pituitary gland was not removed to avoid dangerous conditions. The sellar floor was repaired using an abdominal fat graft or fascia lata from the patient. In Group B, an incision was made in the mucosa of the right nostril, followed by creation of a submucosal plane along the septum up to the anterior wall of the sphenoid sinus. A Killian speculum was inserted, and the septum was subluxed and deviated. The microscope was brought into the operative field, and the sphenoid sinus was opened. The opening was enlarged to permit identification of the lateral portion of the sella, and the sellar position was confirmed under image guidance. The dura was visualized and incised, after which the tumor was identified and excised. Following tumor excision, the sellar floor was packed. The speculum was removed, the septum was returned to the midline, and the mucosa was repositioned. Nasal packing was removed on the fifth postoperative day, after which patients were discharged. Patients were called to the neurosurgery outpatient department six weeks after surgery, when MRI of the brain using plain and pituitary-protocol imaging was performed to calculate postoperative tumor volume and assess the extent of resection. All study information was recorded on the study proforma. Pituitary adenoma was defined as an adenoma of the pituitary gland detected on MRI in a patient planned for transsphenoidal pituitary adenoma surgery. Tumor volume was calculated in milliliters using the specified geometrical formula, ½ × length × width × height, based on tumor dimensions measured on preoperative and postoperative MRI. The extent of resection was assessed on postoperative MRI six weeks after surgery and classified as gross total resection or subtotal resection. Gross total resection (GTR) was defined as tumor excision with residual tumor volume less than 10%, while subtotal resection was defined as residual tumor volume greater than 10%. The primary outcome was the extent of pituitary adenoma resection assessed on postoperative MRI six weeks after surgery. Secondary outcomes included the percentage of tumor resected, tumor volume extracted, and duration of surgery. Data were collected by the principal investigator using a structured study proforma. Demographic characteristics, preoperative and postoperative MRI findings, tumor volume, extent of resection, percentage of tumor resected, and operative duration were documented. Data were entered and analyzed using Statistical Package for the Social Sciences (SPSS), version 25.0. Quantitative variables, including age, duration of symptoms, tumor volume, duration of surgery, and tumor volume extracted, were expressed as mean and standard deviation. Qualitative variables, including gender and extent of tumor resection, were presented as frequency and percentage. The independent-samples t-test was used to compare quantitative variables between the two groups, while the chi-square test or Fisher's exact test was used for categorical variables, as appropriate. Data were stratified according to age, gender, duration of symptoms, tumor volume, and duration of surgery. A p-value ≤0.05 was considered statistically significant. Ethical approval was obtained from the institutional ethics committee, and written informed consent was obtained from each participant before inclusion. Patient confidentiality was maintained, and study information was recorded on the study proforma. The study provided a comparative assessment of endoscopic and microscopic transnasal transsphenoidal surgery for pituitary adenoma, focusing on the extent of tumor resection, percentage of tumor removed, tumor volume extracted, and operative duration.