Long-term result of Memokath urethral sphincter stent in spinal cord injury patients

BACKGROUND: Memokath urethral sphincter stents are used to facilitate bladder emptying in patients with spinal cord injury, but long term follow-up has not been reported. METHODS: Case series of ten men with spinal cord injury who underwent insertion of Memokath stents and were followed for up to nine years. RESULTS: Within four years, the stent had to be removed in nine out of ten patients because of: extensive mucosal proliferation causing obstruction to the lumen of the stent; stone around the proximal end of the stent, incomplete bladder emptying, and recurrent urinary infections; migration of the stent into the bladder related to digital evacuation of bowels; large residual urine; concretions within the stent causing obstruction to flow of urine, and partial blockage of the stent causing frequent episodes of autonomic dysreflexia. In one patient the stent continued to function satisfactorily after nine years. CONCLUSIONS: The Memokath stent has a role as a temporary measure for treatment of detrusor-sphincter dyssynergia in selected SCI patients who do not get recurrent urinary infection and do not require manual evacuation of bowels

Klippel-Feil syndrome – the risk of cervical spinal cord injury: A case report

BACKGROUND: Klippel-Feil syndrome is defined as congenital fusion of two or more cervical vertebrae and is believed to result from faulty segmentation along the embryo's developing axis during weeks 3–8 of gestation. Persons with Klippel-Feil syndrome and cervical stenosis may be at increased risk for spinal cord injury after minor trauma as a result of hypermobility of the various cervical segments. Persons with Klippel-Feil Syndrome often have congenital anomalies of the urinary tract as well. CASE PRESENTATION: A 51-year male developed incomplete tetraplegia in 1997 when he slipped and fell backwards hitting his head on the floor. X-rays of cervical spine showed fusion at two levels: C2 and C3 vertebrae, and C4 and C5 vertebrae. Intravenous urography (IVU) revealed no kidneys in the renal fossa on both sides, but the presence of crossed, fused renal ectopia in the left ilio-lumbar region. This patient had a similar cervical spinal cord injury about 15 years ago, when he developed transient numbness and paresis of the lower limbs following a fall. DISCUSSION AND CONCLUSION: 1) Persons with Klippel-Feil syndrome should be made aware of the increased risk of sustaining transient neurologic deterioration after minor trauma if there is associated radiographic evidence of spinal stenosis. 2) Patients with Klippel-Feil syndrome often have congenital anomalies of the urinary tract. Our patient had crossed, fused, ectopia of kidney. 3) When patients with Klippel-Feil syndrome sustain tetraplegia they have increased chances of developing urinary tract calculi. Treatment of kidney stones may pose a challenge because of associated renal anomalies. 4) Health professionals caring for cervical spinal cord injury patients with Klippel-Feil syndrome and renal anomalies should place emphasis on prevention of kidney stones. A large fluid intake is recommended for these patients, as a high intake of fluids is still the most powerful and certainly the most economical means of prevention of nephrolithiasis

Bladder stones – red herring for resurgence of spasticity in a spinal cord injury patient with implantation of Medtronic Synchromed pump for intrathecal delivery of baclofen – a case report

BACKGROUND: Increased spasms in spinal cord injury (SCI) patients, whose spasticity was previously well controlled with intrathecal baclofen therapy, are due to (in order of frequency) drug tolerance, increased stimulus, low reservoir volume, catheter malfunction, disease progression, human error, and pump mechanical failure. We present a SCI patient, in whom bladder calculi acted as red herring for increased spasticity whereas the real cause was spontaneous extrusion of catheter from intrathecal space. CASE PRESENTATION: A 44-year-old male sustained a fracture of C5/6 and incomplete tetraplegia at C-8 level. Medtronic Synchromed pump for intrathecal baclofen therapy was implanted 13 months later to control severe spasticity. The tip of catheter was placed at T-10 level. The initial dose of baclofen was 300 micrograms/day of baclofen, administered by a simple continuous infusion. During a nine-month period, he required increasing doses of baclofen (875 micrograms/day) to control spasticity. X-ray of abdomen showed multiple radio opaque shadows in the region of urinary bladder. No malfunction of the pump was detected. Therefore, increased spasticity was attributed to bladder stones. Electrohydraulic lithotripsy of bladder stones was carried out successfully. Even after removal of bladder stones, this patient required further increases in the dose of intrathecal baclofen (950, 1050, 1200 and then 1300 micrograms/day). Careful evaluation of pump-catheter system revealed that the catheter had extruded spontaneously and was lying in the paraspinal space at L-4, where the catheter had been anchored before it entered the subarachnoid space. A new catheter was passed into the subarachnoid space and the tip of catheter was located at T-8 level. The dose of intrathecal baclofen was decreased to 300 micrograms/day. CONCLUSION: Vesical calculi acted as red herring for resurgence of spasticity. The real cause for increased spasms was spontaneous extrusion of whole length of catheter from subarachnoid space. Repeated bending forwards and straightening of torso for pressure relief and during transfers from wheel chair probably contributed to spontaneous extrusion of catheter from spinal canal in this patient

Elastic modulus of shape-memory NiTi from in situ neutron diffraction during macroscopic loading, instrumented indentation, and extensometryl

The elastic modulus of B19\u27 shape-memory NiTi was determined using three techniques; from the response of lattice planes measured using in situ neutron diffraction during loading, instrumented indentation using a spherical indenter and macroscopic extensometry. The macroscopic measurements resulted in a modulus of 68 GPa, significantly less than the 101 GPa from indentation and the lattice plane average of 109 GPa from neutron diffraction. Evidence from the neutron measurements suggests that the disparity derives from the onset of small amounts of twinning at stresses less that 40 MPa, which might otherwise be considered elastic from a macroscopic view point

Measuring motion with kinematically redundant accelerometer arrays: theory, simulation and implementation

This work presents two schemes of measuring the linear and angular kinematics of a rigid body using a kinematically redundant array of triple-axis accelerometers with potential applications in biomechanics. A novel angular velocity estimation algorithm is proposed and evaluated that can compensate for angular velocity errors using measurements of the direction of gravity. Analysis and discussion of optimal sensor array characteristics are provided. A damped 2 axis pendulum was used to excite all 6 DoF of the a suspended accelerometer array through determined complex motion and is the basis of both simulation and experimental studies. The relationship between accuracy and sensor redundancy is investigated for arrays of up to 100 triple axis (300 accelerometer axes) accelerometers in simulation and 10 equivalent sensors (30 accelerometer axes) in the laboratory test rig. The paper also reports on the sensor calibration techniques and hardware implementation