Comparative analysis between epidural (Gaeltec) and subdural (Camino) intracranial pressure probes.

The new fiberoptic Camino system has recently been introduced for clinical intracranial pressure (ICP) monitoring. We compared the subdural Camino system with the well-established epidural Gaeltec system in both in vitro and clinical conditions. In the in vitro experiments the intracranial vault was simulated by a tightly closed, fluid-filled box (0.9% sodium chloride) with the two probes inside. We simulated pulsating waveforms with a jet ventilator. No difference between the simulated curve patterns and values could be detected. In the clinical studies, both probes were implanted in 10 patients who had either head injuries, subarachnoid hemorrhage, or intracerebral hemorrhage. The in vivo comparison revealed no significant difference between the two systems in the recorded pressures in group 1 (ICP less than 20 mm Hg). The subdurally placed Camino probe showed insignificantly lower ICP values than did the extradural Gaeltec probe. Although group 2 (ICP greater than 20 mm Hg) waveforms were nearly identical, significant differences (p less than 0.01) in pressure measurements (systolic, diastolic, and mean) occurred (Camino, 18 +/- 3 mm Hg; Gaeltec, 27 +/- 3 mm Hg). Correlation coefficients for mean ICP values were 0.82 in group 1 and 0.49 in group 2. Problems with the Camino probe were usually mechanical and occurred in 2 patients. The problems were either easy to recognize or manifested as an ostensibly pathologic curve. No infection occurred with either system during or following implantation. The dissimilar characteristics of the two probes can be ascribed to their different extradural and subdural implantation sites. The Gaeltec probe was more durable over the period of implantation, which averaged 98 hours and ranged from 44 to 298 hours.(ABSTRACT TRUNCATED AT 250 WORDS)