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

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).

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.

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).

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