Risk factors for olfactory dysfunction after transsphenoidal pituitary adenoma resection: A systematic review and...

Pituitary adenomas account for approximately 10-20% of intracranial tumors, and endonasal transsphenoidal resection is a standard treatment approach. However, postoperative olfactory dysfunction occurs in up to 30% of patients and can markedly impair quality of life. Existing evidence regarding its risk factors remains inconsistent.

This systematic review and meta-analysis aimed to evaluate factors associated with postoperative olfactory dysfunction after transsphenoidal pituitary adenoma surgery, with particular focus on patient-related characteristics, surgical and reconstruction-related factors, and postoperative management strategies.

A PRISMA-compliant systematic review and meta-analysis was conducted. Relevant publications up to January 2026 were retrieved from PubMed, the Cochrane Library, Embase, Web of Science, Google Scholar, CNKI, Wanfang, and VIP. Randomized controlled trials and observational studies involving adults without preexisting olfactory or neurological disorders were included. Data extraction and statistical analyses were performed using R software.

A total of 11 studies involving 802 participants were included; the number of participants contributing to each pooled analysis varied according to data availability. Advanced age, smoking history, and nasoseptal or nasal mucosal flap reconstruction were associated with an increased risk of postoperative olfactory dysfunction. Postoperative nasal irrigation showed a potential protective association. No significant associations were observed for sex, tumor functionality, superior turbinatectomy, or postoperative electrolyte disturbance. Findings for middle turbinatectomy and postoperative cerebrospinal fluid leakage were exploratory because of substantial unresolved heterogeneity. A limited pooled comparison suggested a higher reported risk of olfactory dysfunction in the endoscopic group than in the microsurgical group, but this result should be interpreted cautiously.

Postoperative olfactory dysfunction after transsphenoidal pituitary adenoma surgery was associated with multiple patient-related, surgical, and postoperative management factors. Because most pooled estimates were derived from unadjusted data and several comparisons included few studies, these findings should be interpreted cautiously. Further prospective studies using standardized olfactory assessment and adjusted analyses are needed to clarify clinically relevant factors.