The Meningeal Pressure Dressing is a rigid semi-circular cranial appliance that fits over the top and sides of the skull, secured by four self-tightening anchor straps that locate against the zygomatic arches and occipital ridge. Its inner surface is lined with a lattice of piezoelectric pressure sensors and a distributed array of micro-needles — each no longer than two millimeters — that penetrate the scalp to deliver a proprietary osmotic compound called Durasolv directly into the subgaleal space. Durasolv works by drawing interstitial fluid away from the meninges through osmotic gradient manipulation, reducing intracranial pressure without the need for surgical decompression. The device monitors pressure in real time and modulates Durasolv delivery in response, attempting to hold intracranial pressure within a survivable range for up to six hours.

The Crown's distinctive quality is its accessibility: it requires no surgical training to apply, no sterile field, and no diagnostic imaging beyond what the device itself provides through its pressure-sensor array. A medic can fit it in under ninety seconds. Helix Biosystems designed it explicitly for scenarios where traumatic brain injury occurs far from neurosurgical infrastructure — which in GLMZ describes most of the city. The device cannot resolve the underlying injury, but it can extend the window in which resolution is possible, and in a city where the nearest licensed neurosurgeon may be four transit hours away, that window is the difference between outcome and obituary.

The Meningeal Pressure Dressing is standard issue in Arcturus Defense Solutions forward medical kits — a procurement relationship that has made Helix Biosystems quietly wealthy — and is distributed through licensed channels to paramedic services in the inner and mid-ring districts. Outer-ring circulation is patchier, and in the furthest corridors of GLMZ's periphery, the device is more likely to be found secondhand, recalibrated by someone who understood enough of the underlying engineering to make it functional again. These recalibrated units carry the street name 'The Halo Press,' and their reliability is a subject of significant debate.