No abstract

Maintaining the patency of indwelling drainage devices is critical in preventing further complications following an intraventricular hemorrhage (IVH) and other chronic disease management. Surgeons often use drainage devices to remove blood and cerebrospinal fluid but these catheters frequently become occluded with hematoma. Using an implantable magnetic microactuator, we created a self-clearing catheter that can generate large enough forces to break down obstructive blood clots by applying time-varying magnetic fields. In a blood-circulating model, our self-clearing catheters demonstrated a > 7x longer functionality than traditional catheters (211 vs. 27 min) and maintained a low pressure for longer periods (239 vs. 79 min). Using a porcine IVH model, the self-clearing catheters showed a greater survival rate than control catheters (86% vs. 0%) over the course of 6 weeks. The treated animals also had significantly smaller ventricle sizes 1 week after implantation compared to the control animals with traditional catheters. Our results suggest that these magnetic microactuator-embedded smart catheters can expedite the removal of blood from the ventricles and potentially improve the outcomes of critical patients suffering from often deadly IVH.

Congenital epidermoid cysts are slow-growing, mass lesions caused by the abnormal inclusion of neuroectodermal tissue within the developing central nervous system. Subtotal excision of epidermoid cysts increases the risk of early recurrence of clinical signs. A 4-year-old female spayed boxer was presented with a 4-month history of ambulatory paraparesis and proprioceptive ataxia. Neurological examination localized a T3-L3 myelopathy. MRI revealed a T1 iso- to hypointense, T2 and FLAIR hyperintense, rim-enhancing mass at the level of the T9-T10 vertebrae resulting in extradural compression of the spinal cord. This was histopathologically confirmed as an extradural epidermoid cyst following subtotal excision. MRI performed 2 months post-operatively revealed a significant decrease of the lesion volume. The dog was neurologically normal following the surgery however re-presented 28 months later with recurrence of clinical signs. A 28-month post-operative MRI revealed substantial enlargement of the epidermoid cyst. The dog was subsequently taken for repeat decompressive surgery. At 6 months from the repeat surgery, the dog was neurologically static with mild proprioceptive deficits. The case report highlights the clinical and MRI features of a recurrent extradural spinal epidermoid cyst treated by subtotal excision.

Maintaining the patency of indwelling drainage devices is critical in preventing further complications following an intraventricular hemorrhage (IVH) and other chronic disease management. Surgeons often use drainage devices to remove blood and cerebrospinal fluid but these catheters frequently become occluded with hematoma. Using an implantable magnetic microactuator, we created a self-clearing catheter that can generate large enough forces to break down obstructive blood clots by applying time-varying magnetic fields. In a blood-circulating model, our self-clearing catheters demonstrated a 7x longer functionality than traditional catheters (211 vs. 27 min) and maintained a low pressure for longer periods (239 vs. 79 min). Using a porcine IVH model, the self-clearing catheters showed a greater survival rate than control catheters (86% vs. 0%) over the course of 6 weeks. The treated animals also had significantly smaller ventricle sizes 1 week after implantation compared to the control animals with traditional catheters. Our results suggest that these magnetic microactuator-embedded smart catheters can expedite the removal of blood from the ventricles and potentially improve the outcomes of critical patients suffering from often deadly IVH.