Cerebral microembolization during primary total hip arthroplasty and neuropsychologic outcome: a pilot study.

BACKGROUND: Intraoperative cerebral microembolization occurs in a substantial proportion of patients undergoing THA. Historically, postoperative cognitive dysfunction has been attributed to different factors, including anesthesia, but the influence of the surgery has not been thoroughly examined.

QUESTIONS/PURPOSES: We conducted a prospective, controlled clinical trial to assess intraoperative cerebral microembolization during THA and neuropsychologic outcome.

METHODS: The presence of a patent foramen ovale (PFO) also was investigated, using transcranial Doppler, to determine whether this affected cerebral microembolic incidence and load and whether microemboli occurred as a result of specific surgical activity. Forty-five patients were recruited who underwent THA and neuropsychologic assessment; a battery of tests was administered preoperatively and at 6 weeks and 6 months postoperatively.

RESULTS: Overall, patients showed improvement in total neuropsychologic change scores at both postoperative intervals. The incidence of cerebral microembolization for THA was 23%. The prevalence of PFO was 37%. PFO did not appear to influence microemboli load or incidence. More microemboli were seen during femoral component insertion and impaction.

CONCLUSIONS: Intraoperative cerebral microembolization occurs in a substantial proportion of patients during THA recorded by transcranial Doppler. The microemboli load is low and is not influenced by the presence of PFO. Certain surgical activities seem responsible for greater cerebral microemboli generation. However, neuropsychologic outcome was not affected postoperatively by microemboli or other operative or patient variables.