Reduction of bone dust with ultrasonic bone aspiration: implications for retrosigmoid vestibular schwannoma removal.

Abstract

Postoperative headache is not uncommon after retrosigmoid vestibular schwannoma removal. Bone dust dispersed into the subarachnoid space during drilling may be responsible. If dispersion could be reduced, headache incidence might be decreased. An ultrasonic bone aspirator (UBA) containing an integrated suction at the tip may more effectively suction bone dust created during bone removal. The objective is to determine whether a UBA results in less bone dust dispersion than a standard otologic drill. Cadaveric temporal bone quantitative model. Laboratory. Temporal bone blocks were placed in a watertight enclosure. Under irrigation, bone was removed by use of either a drill or a UBA. The settings of the UBA were varied. The irrigant containing bone dust was microfiltered, and bone dust was weighed. Differences were compared across groups (n = 2-9 per group). Ablation times were also recorded (n = 3 per group). Only 3% (SD = 1.6%, n = 7) of the drilled bone mass was re-collected as bone dust with the UBA under optimized settings (power = 15%, suction = 100%, irrigation = 15 mL/min) compared with 81% (SD = 10%, n = 4) with the drill and external suction (P < .001). Increasing UBA power and reducing suction led to significantly more bone dust dispersal than with optimized settings. Varying irrigation did not have a significant effect. Bone ablation time was 1.4 times longer with the UBA at 50% power compared with the drill at maximum power. The UBA resulted in approximately 25 times less bone dust dispersion than the otologic drill at optimized settings.