Pituitary Adenoma Surgery: A Single-center Experience of Over 8,500 Operations

Technical Summary: Pituitary Adenoma Surgery – A Single-Center Experience of Over 8,500 Operations

Problem Statement
The surgical management of pituitary adenomas has evolved from simple decompression to a complex discipline requiring the maximally safe radical resection of tumors while preserving endocrine, neurological, and visual functions. Despite the availability of advanced technologies, long-term outcome data from large-scale series remain limited. There is a critical need to establish benchmarks for surgical volume, complication rates, and remission outcomes to optimize patient care, particularly for complex and functioning adenomas which often require multidisciplinary expertise.

Methodology
This study presents a retrospective analysis of 8,514 patients treated for pituitary adenomas at the Burdenko Neurosurgery Center in Moscow, Russia, between 2005 and 2025. The cohort included all tumor subtypes and sizes, with a median age of 46.5 years and a female-to-male ratio of 1.5:1.

• Surgical Approach: The primary approach was endoscopic transnasal adenomectomy, utilized in 96.3% of cases (n=8,196). The remaining 3.7% (n=318), primarily those with giant tumors extending into the posterior cranial fossa or lateral ventricles, underwent transcranial approaches or staged procedures.
• Technique Refinements: The authors employ a monomanual technique where the surgeon holds the endoscope in the left hand and instruments in the right, allowing for autonomous operation or flexible assistance. The surgical protocol emphasizes the preservation of the sphenopalatine artery and nasal septal mucosa to facilitate mucoperiosteal flap reconstruction.
• Resection Algorithm: Tumor removal follows a specific sequence: endo- and infrasellar components first, followed by suprasellar components, and finally laterosellar fragments within the cavernous sinuses to prevent uncontrolled bleeding that would obscure suprasellar visualization.
• Reconstruction: Skull base defect closure utilizes autologous materials (nasal septal bone, fascia, fat) and fibrin glue. For defects with intraoperative cerebrospinal fluid (CSF) leakage, a "sandwich" technique with a vascularized nasoseptal flap is employed.
• Postoperative Protocol: Patients undergo immediate postoperative CT, hormonal replacement as needed, and ENT evaluation for occult CSF leakage. Follow-up contrast MRI is performed at 3–4 months.

Key Contributions

• Large-Scale Data: The study provides a comprehensive dataset from over 8,500 operations, offering robust statistical power regarding long-term outcomes and complication rates.
• Standardized Protocols: The paper details a refined, standardized algorithm for endoscopic transnasal surgery, including specific techniques for tumor resection sequencing and skull base reconstruction that have evolved over two decades.
• Evolution of Practice: It documents the shift from transcranial to endoscopic approaches and the abandonment of external lumbar drainage in favor of hypertonic iso-oncotic sodium chloride solutions for managing intracranial pressure, citing reduced infectious risks.
• Volume-Outcome Correlation: The authors argue that complex cases, including microadenomas and macroadenomas >30 mm, should be managed in high-volume "reference" centers by surgeons with extensive experience (specifically citing >200 adenomectomies).

Results

• Resection Extent: Gross total resection (100%) was achieved in 80% of patients. Outcomes were highest for tumors without laterosellar nodules or infiltrative growth.
• Biochemical Remission: In functioning adenomas, biochemical remission was achieved in 90% of the cohort. Remission rates were highest for corticotropinomas (92%) and tumors ≤20 mm.
• Visual and Neurological Outcomes: Visual improvement occurred in 66% of patients, while deterioration was observed in 4%. New oculomotor disturbances occurred in 3%, primarily in patients with laterosellar extension, and typically resolved within three months.
• Complications: The overall complication rate was 7%.
  • CSF Leakage: Occurred in 0.5% of cases with an intact capsule and 3% with intraoperative leakage. The rate of leakage has shown a gradual decline over time due to improved reconstruction techniques.
  • Meningitis: 1%.
  • Vascular Injury: Internal carotid artery (ICA) injury occurred in 0.06% (5 patients).
  • Hemorrhage: Postoperative hemorrhage requiring revision was identified in 0.2% of cases.
• Mortality: The overall mortality rate was 0.59%, declining to less than 0.5% in the last decade. The majority of deaths were associated with giant adenomas, caused primarily by postoperative hemorrhage (52%), ischemic events (22%), or infectious complications (18%).

Significance and Claims
The authors claim that endoscopic transnasal surgery, when performed in experienced high-volume centers, achieves excellent outcomes with low morbidity and mortality. The study supports the establishment of surgical volume and remission rate benchmarks to optimize patient care. Specifically, the paper asserts that the treatment of complex and functioning pituitary adenomas should be entrusted only to surgeons with extensive experience in endoscopic transnasal skull base surgery. The authors suggest that surgeons with fewer than 200 adenomectomies and remission rates below 60–65% for acromegaly may not be suitable candidates for operating on all functioning pituitary adenomas. The findings underscore the necessity of multidisciplinary expertise and centralized care for achieving the best possible patient outcomes.