Implanted intracranial pressure sensors: mechanisms, fabrication, and system integration.

Intracranial pressure (ICP) is a key physiological parameter for the diagnosis and management of traumatic brain injury, hydrocephalus, stroke, and other neurological disorders. ICP sensors are typically required to provide accurate pressure measurement at low pressure while maintaining long-term stability in biofluid environments. Although conventional liquid-based ICP systems remain the clinical standard, their bulky and tethered configurations increase the risk of infection and tissue injury and restrict patient mobility. Advances in miniaturized implantable sensors have created new opportunities for continuous and ambulatory ICP monitoring. This review summarizes recent developments in implantable ICP sensing technologies, covering sensing mechanisms, materials, designs, and fabrication processes. Wireless communication approaches together with emerging transient bioresorbable ICP sensors designed that eliminate the need for surgical removal are also discussed. Finally, the review highlights the remaining technical challenges and outlines future research directions toward long-term, minimally invasive ICP monitoring systems.