Indication for surgery and the risk of postoperative nausea and vomiting after craniotomy: a case-control study.

Background: The primary hypothesis of the study is that acoustic neuroma (AN) surgery and microvascular decompression (MVD) of cranial nerves increase the risk of postoperative nausea and vomiting (PONV).

Methods: We designed a retrospective case-control study matched on age, sex, and year of surgery (≤2005 and >2005). Year of surgery was noted as a potential confounder, because routine antiemetic prophylaxis was strongly encouraged at the study site in 2005. Cases of PONV in the recovery room were matched to controls in a 1:2 manner using a perioperative database. Charts were then reviewed for the following data: American Society of Anesthesiologists grade, smoking status, craniotomy location, craniotomy indication, and type of anesthetic administered.

Results: The final analysis included 117 cases that were matched with 185 controls. Patients had a mean age of 50 years (SD=13), and 65% were female. Overall, the majority of craniotomies were supratentorial (70%) and performed for tumor resection (41%). On multivariable analysis, MVD [odds ratio (OR)=6.7; 95% confidence interval (CI), 2.0-22.7; P=0.002], AN (OR=3.3; 95% CI, 1.0-11.0; P=0.05), and epilepsy surgery (OR=2.8; 95% CI, 1.1-7.5; P=0.04) were associated with an increased likelihood of PONV when compared with tumor surgery. There was effect modification of total intravenous anesthesia by location of surgery (P-interaction=0.02). The benefit of total intravenous anesthesia on PONV was observed in supratentorial (OR=0.41; 95% CI, 0.17-0.96; P=0.04) but not infratentorial location (OR=2.6; 95% CI, 0.78-8.7; P=0.11).

Conclusions: MVD and AN resection were associated with an increased likelihood of PONV compared with craniotomies performed for other tumor resection.