A chronic implant for intracerebral mass spectrometric gasometry in the rhesus monkey

A cranial implant was developed to facilitate mass spectrometric gasometry in cerebral tissue of conscious primates. It is permanently fixed to the skull and allows repeated introduction of a Teflon diffusion membrane into the cerebrum. The implant is simple to manufacture and mount. It has been tolerated well with repeated introduction of the catheter for more than 6 mo in 10 rhesus monkeys. The preparation avoids the complication and artifacts of an acute surgical preparation for investigation of cerebral pO2 and CO2.