Browsing by Author "Lee, Albert"

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    Anti-biofouling implantable catheter using thin-film magnetic microactuators
    (Elsevier, 2018-11-10) Yang, Qi; Park, Hyunsu; Nguyen, Tran N.H.; Rhoads, Jeffrey F.; Lee, Albert; Bentley, R. Timothy; Judy, Jack W.; Lee, Hyowon; Neurological Surgery, School of Medicine
    Here we report on the development of polyimide-based flexible magnetic actuators for actively combating biofouling that occurs in many chronically implanted devices. The thin-film flexible devices are microfabricated and integrated into a single-pore silicone catheter to demonstrate a proof-of-concept for a self-clearing smart catheter. The static and dynamic mechanical responses of the thin-film magnetic microdevices were quantitatively measured and compared to theoretical values. The mechanical fatigue properties of these polyimide-based microdevices were also characterized up to 300 million cycles. Finally, the biofouling removal capabilities of magnetically powered microdevices were demonstrated using bovine serum albumin and bioconjugated microbeads. Our results indicate that these thin-film microdevices are capable of significantly reducing the amount of biofouling. At the same time, we demonstrated that these microdevices are mechanically robust enough to withstand a large number of actuation cycles during its chronic implantation.
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    Intrathecal Baclofen Pump Migration Into the Peritoneal Cavity: A Case Report
    (Kowsar Medical, 2016-06) Kovanda, Timothy J.; Pestereva, Ecaterina; Lee, Albert; Department of Neurological Surgery, IU School of Medicine
    INTRODUCTION: Intrathecal baclofen pumps are valuable treatment options for those with cerebral palsy. Although subfascial baclofen pump placement is generally preferred over a subcutaneous pump placement due to lower infection rates, rare complications can occur with the subfascial approach such as pump migration. CASE PRESENTATION: The authors here describe a case of baclofen pump migration into the peritoneal cavity of a 26-year-old male patient with cerebral palsy, shunted hydrocephalus, and epilepsy. Because the patient's pump could not be palpated on exam and hence refilled, imaging was undertaken, but did not reveal clear evidence of pump migration. Surgery afterward confirmed that the pump had migrated into the peritoneal cavity through a fascial defect. Baclofen pump had to be replaced instead subcutaneously as well as the patient later had to be readmitted for 2 ventriculoperitoneal shunt revisions due to progression of his hydrocephalus. CONCLUSIONS: Intraperitoneal migration of a subfascially placed baclofen pump is a rare, yet serious complication, which has been reported only once in the literature. We advise neurosurgeons to have a low level of threshold in confirming the location of a baclofen pump with imaging and surgical exploration if necessary in order to avoid detrimental outcomes such as bowel perforation.
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    Piezoresistor-Embedded Multifunctional Magnetic Microactuators for Implantable Self-Clearing Catheter
    (Institute of Electrical and Electronics Engineers, 2019-02-15) Yang, Qi; Lee, Albert; Bentley, R. Timothy; Lee, Hyowon; Neurological Surgery, School of Medicine
    Indwelling catheters are used widely in medicine to treat various chronic medical conditions. However, chronic implantation of catheters often leads to a premature failure due to biofilm accumulation. Previously we reported on the development of a self-clearing catheter by integrating polymer-based microscale magnetic actuators. The microactuator provides an active anti-biofouling mechanism to disrupt and remove adsorbed biofilm on demand using an externally applied stimulus. During an in vivo evaluation of self-clearing catheter, we realized that it is important to periodically monitor the performance of implanted microactuators. Here we integrate gold-based piezoresistive strain-gauge on our magnetic microactuators to directly monitor the device deflection with good sensitivity (0.035%/Deg) and linear range (±30°). With the integrated strain-gauge, we demonstrate the multi-functional capabilities of our magnetic microactuators that enable device alignment, flow-rate measurement, and obstruction detection and removal towards the development of chronically implantable self-clearing smart catheter.
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    Subarachnoid-to-Subarachnoid Shunt for Correction of Nonfunctioning Baclofen Pump in a Severe Case of Chronic Debilitating Post–Spinal Cord Injury Spasticity
    (Elsevier, 2018-02) Bakare, Adewale A.; Weyhenmeyer, Jonathan; Lee, Albert; Neurological Surgery, School of Medicine
    Background Perhaps the most disabling condition seen in patients with spinal cord injury (SCI) is spasticity. Spasticity is characterized as hyperreflexia and hypertonicity as a result of damage to the supraspinal tracts in the aftermath of SCI. Intrathecal baclofen (ITB) is the mainstay therapy for spasticity unresponsive to oral baclofen. One of the problems associated with post-SCI spasticity unresponsive to ITB is the development of scar tissue that prevents the diffusion of baclofen in the desired spinal cord area. This case offers a unique strategy to deal with multilevel scar tissue. Clinical Presentation This 46-year-old paraplegic male with a T8 SCI whose spasticity had been well managed with ITB therapy for many years recently suffered intractable spasticity necessitating multiple reoperations for a nonfunctioning ITB catheter secondary to extensive scar tissue and intrathecal adhesions. Placement of a subarachnoid-to-subarachnoid shunt eliminated the problem of extensive scar tissue preventing adequate baclofen therapy. Conclusions After undergoing multilevel thoracic and lumbar laminectomies with subarachnoid-to-subarachnoid spinal shunt, the patient's spasticity was finally brought under control with adequate daily baclofen infusion. This case demonstrates a creative way to address ITB catheter failure before considering other measures, such as neuroablative procedures (e.g., rhizotomy, myelotomy). This case reinforces the recommendation that ablative procedures, which have far greater complications, should be reserved for patients who have failed medical or other nonablative therapies.