The author Bull advised physicians: "After removal of wax, inspect thoroughly to make sure none remains. This advice might seem superfluous, but is frequently ignored." This was confirmed by Sharp et al., who, in a survey of 320 general practitioners, found that only 68% of doctors inspected the ear canal after syringing to check that the wax was removed. As a result, failure to remove the wax from the canal made up approximately 30% of the complications associated with the procedure. Other complications included otitis externa (swimmer's ear), which involves inflammation or bacterial infection of the external acoustic meatus, as well as pain, vertigo, tinnitus, and perforation of the ear drum. Based on this study, a rate of major complications in 1/1000 ears syringed was suggested.