Dynamic telescopic craniotomy: a cadaveric study of a novel device and technique

Abstract

OBJECT The authors assessed the feasibility of the dynamic decompressive craniotomy technique using a novel cranial fixation plate with a telescopic component. Following a craniotomy in human cadaver skulls, the telescopic plates were placed to cover the bur holes. The plates allow constrained outward movement of the bone flap upon an increase in intracranial pressure (ICP) and also prevent the bone flap from sinking once the ICP normalizes. The authors compared the extent of postcraniotomy ICP control after an abrupt increase in intracranial volume using the dynamic craniotomy technique versus the standard craniotomy or hinge craniotomy techniques. METHODS Fixation of the bone flap after craniotomy was performed in 5 cadaver skulls using 3 techniques: 1) dynamic telescopic craniotomy, 2) hinge craniotomy, and 3) standard craniotomy with fixed plates. The ability of each technique to allow for expansion during intracranial hypertension was evaluated by progressively increasing intracranial volume. Biomechanical evaluation of the telescopic plates with load-bearing tests was also undertaken. RESULTS Both the dynamic craniotomy and the hinge craniotomy techniques provided significant control of ICP during increases in intracranial volume as compared with the standard craniotomy technique. With the standard craniotomy, ICP increased from a mean of 11.4 to 100.1 mm Hg with the addition of 120 ml of intracranial volume. However, with the dynamic craniotomy, the addition of 120 ml of intracranial volume increased the ICP from a mean of 2.8 to 13.4 mm Hg, maintaining ICP within the normal range as compared with the standard craniotomy (p = 0.04). The dynamic craniotomy was also superior in controlling ICP as compared with the hinge craniotomy, providing expansion for an additional 40 ml of intracranial volume while maintaining ICP within a normal range (p = 0.008). Biomechanical load-bearing tests for the dynamic telescopic plates revealed rigid restriction of bone-flap sinking as compared with standard fixation plates and clamps. CONCLUSIONS The dynamic telescopic craniotomy technique with the novel cranial fixation plate provides superior control of ICP after an abrupt increase in intracranial volume as compared with the standard craniotomy and hinge craniotomy techniques.

Dynamic Craniotomy With NuCrani Reversibly Expandable Cranial Bone Flap Fixation Plates: A Technical Report

“…Dynamic craniotomy enables an unhinged outward bone flap migration with an increased intracranial volume expansion compared with a hinge craniotomy 1-3 and provides another armamentarium in the management of increased ICP from postoperative complications such as brain swelling and/or rehemorrhage.…”

“…Decompressive craniotomy is effective in controlling increased ICP and is life saving for patients with malignant strokes and traumatic brain injury. 1-7,9-17 ICP elevation is frequently encountered in severe traumatic brain injury, 18-20 malignant strokes, 5,6,21-25 aneurysmal subarachnoid hemorrhage, 26-28 intracerebral hemorrhage, 29-31 and brain tumors. 32,33 Uncontrollably elevated ICP has also been associated with poor patient outcomes.…”

Hinge/floating craniotomy as an alternative technique for cerebral decompression: a scoping review

“…This concept is further reinforced by a biomechanical study in human cadaver skulls [ 30 ], which compared DC to HC and ‘dynamic decompressive craniotomy’ and the effect on ICP after abrupt increase in intracranial volume. They found that both the dynamic craniotomy and the HC techniques provided significant control of ICP during 120 ml increase in intracranial volume as compared with craniotomy rigidly fixed with plates (4.86 mmHg, 8.36 mmHg, 44.84 mmHg, respectively).…”

“…Obviously, the patients included in the studies of the present scoping review are not directly comparable to the RESCUEicp population but this figure can give an indication as to the proportion of patients with refractory ICP despite DC. This concept is further reinforced by a biomechanical study in human cadaver skulls [30], which compared DC to HC and 'dynamic decompressive craniotomy' and the effect on ICP after abrupt increase in intracranial volume. They found that both the dynamic craniotomy and the HC techniques provided significant control of ICP during 120 ml increase in intracranial volume as compared with craniotomy rigidly fixed with plates (4.86 mmHg, 8.36 mmHg, 44.84 mmHg, respectively).…”

Bone flap elevation for intracranial EEG monitoring: technical note

“…4 The idea of expanding intracranial volume is not unique to the field of epilepsy surgery involving implantation of intracranial electrodes but has been explored in the context of cerebral edema from traumatic brain injuries and stroke. 6,9,13 Compared with other situations in which efforts have been made to reduce the number of necessary surgeries (e.g., when a bone flap rises relative to the surrounding calvaria in response to intracranial hypertension but settles downward with resolution of cerebral edema), electrode implantation surgery invariably needs to be followed by another surgery for removal of the electrodes. Therefore, it is possible to secure and keep the bone flap elevated during monitoring using the described technique, as this can be easily reversed during the second surgery.…”