Microfluidic drug delivery devices

The methods, systems, and devices disclosed herein generally involve convection enhanced delivery of drugs to a target region within a patient. Microfluidic catheter devices are disclosed that are particularly suitable for targeted delivery of drugs via convection, including devices capable of multi-directional drug delivery, devices that control fluid pressure and velocity using the venturi effect, and devices that include conformable balloons. Methods of treating various diseases using such devices are also disclosed, including methods of treating cerebral and spinal cavernous malformations, cavernomas, and hemangiomas, methods of treating neurological diseases, methods of treatment using multiple microfluidic delivery devices, methods of treating hearing disorders, methods of spinal drug delivery using microfluidic devices, and methods of delivering stem cells and therapeutics during fetal surgery. Methods of manufacturing such devices are also disclosed.