MINIMALLY INVASIVE BEDSIDE CRANIOTOMY USING A SELF-CONTROLLING PRE-ADJUSTABLE MECHANICAL TWIST DRILL TREPHINE

BACKGROUND Craniotomy with a mechanical twist drill is a standard, min imally invasive procedure in neurosurgery, widely used for the drainag e of chronic subdural hematomas and the placement of ventricular drain s. Nevertheless, the use of a standard twist drill trephine bears the risk of causing cerebral lesions. METHOD A commercially available mech anical twist drill system has been modified by a special self-controll ing drill and a pre-adjustable distance holder that limits intracerebr al penetration. After initial cadaver testing, the modified trephine h as been used for 65 trephinations in patients (37 chronic subdural hem atomas, 21 external ventricular drains, 6 frontal hygromas, 1 tumor cy st). RESULTS There were no complications related to the modified treph ine; cerebral lesions caused by drilling too deeply or by uncontrolled penetration were safely prevented. In our series no procedure related infections occurred, and the drilling time was reduced significantly. CONCLUSION The described modified mechanical twist drill enables fast , easy, and safe craniotomy without jeopardizing the advantages of a m echanical twist drill. Therefore, it can be recommended particularly f or difficult emergency conditions. (C) 1998 by Elsevier Science Inc.