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ABSTRACT: The electrode-tissues interface (ETI) is one of the key issues in implantable devices such as stimulators and sensors. Once the stimulator is implanted, safety and reliability become more and more critical. In this case, modeling and monitoring of the ETI are required. We propose an empirical model for the ETI and a dedicated integrated circuit to measure its corresponding complex impedance. These measurements in the frequency range of 1 Hz to 100 kHz were achieved in acute dog experiments. The model demonstrates a closer fitting with experimental measurements. In addition, a custom monitoring device based on a stimuli current generator has been completed to evaluate the phase shift and voltage across the electrodes and to transmit wirelessly the values to an external controller. This integrated circuit has been fabricated in a CMOS 0.18 microm process, which consumes 4 mW only during measurements and occupies an area of 1 mm(2).
Biomedical Materials 04/2007; 2(1):S7-S15. · 2.16 Impact Factor
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ABSTRACT: Tonic immobility (TI) is a behavioral response to a sudden constraint and inversion in the rabbit. TI is characterized by a long-lasting immobilization, abolition of righting reflex, leg tremors, and waxy flexibility of the extremities. However, during TI autonomic functions do not seem significantly altered. We have used TI as a method to obviate the effect of anesthesia when recording urodynamic parameters during filling of the bladder. Our results suggest that, indeed, autonomic functions related to the filling phase of the micturition cycle are not altered by TI.
Neurourology and Urodynamics 10/2005; 5(4):411 - 418. · 2.96 Impact Factor
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ABSTRACT: Mesenchymal tumors of the urinary bladder are rare and the majority of them are malignant. We report two cases of leiomyoma of the urinary bladder presenting with symptoms of bladder outlet obstruction. The first patient was managed with staged transurethral resections, and the second with holmium laser transurethral inoculation. The outcome was excellent in both cases. A review of the literature is also outlined.
The Canadian Journal of Urology 11/2004; 11(5):2411-3. · 0.64 Impact Factor
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BJU International 01/2003; 90(9):870-1. · 2.84 Impact Factor
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ABSTRACT: To present the initial experience of a senior urology resident with holmium laser enucleation of the prostate (HoLEP) and to address the difficulties encountered while learning this technique, describing the detailed operative technique and pitfalls.
Between July and August 2001, 27 patients were treated using HoLEP administered by one senior urology resident (A.H.) under the supervision of an experienced urologist (M.M.E.). Patients were assessed before and 1 month after HoLEP by the International Prostate Symptom Score (IPSS), the associated quality-of-life (QoL) score, and measurements of maximum urinary flow rate (Qmax) and postvoid residual urine (PVR) volume. The prostate volume was measured before HoLEP using transrectal ultrasonography. The 27 patients were compared retrospectively with 118 who underwent HoLEP by the supervising urologist. Each of the 27 procedures was taped and reviewed.
The mean (range) prostate size was 54.8 (21-122) mL (A.H.) and 61.7 (20.5-172) mL (M.M.E.). The mean operative duration was 98 (50-175) min and the mean enucleation time 68 (29-108) min. The improvements in IPSS, QoL score, Qmax and PVR were highly significant (P < 0.001), with mean values before and after HoLEP of 16.8 and 8.2, 3.1 and 1.4, 7.7 and 20.8 mL/s, and 232 and 41.3 mL, respectively. Of the 27 patients, 23 (85%) were catheter-free on the first day after HoLEP; the mean hospital stay was 1.8 days. All these results were comparable with the results of 118 patients treated by M.M.E. The two most difficult technical steps identified were the initial apical enucleation and the incision of the remaining antero-apical mucosal attachment of the lateral lobes. The operator became adept with the HoLEP technique after a mean of 20 patients.
HoLEP can be learnt but requires longer training than standard transurethral resection. Extensive experience with transurethral surgery and the supervision of an experienced urologist are prerequisites for success.
BJU International 12/2002; 90(9):863-9. · 2.84 Impact Factor
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ABSTRACT: Objective To present the initial experience of a senior urology resident with holmium laser enucleation of the prostate (HoLEP) and to address the difficulties encountered while learning this technique, describing the detailed operative technique and pitfalls.Patients and methods Between July and August 2001, 27 patients were treated using HoLEP administered by one senior urology resident (A.H.) under the supervision of an experienced urologist (M.M.E.). Patients were assessed before and 1 month after HoLEP by the International Prostate Symptom Score (IPSS), the associated quality-of-life (QoL) score, and measurements of maximum urinary flow rate (Qmax) and postvoid residual urine (PVR) volume. The prostate volume was measured before HoLEP using transrectal ultrasonography. The 27 patients were compared retrospectively with 118 who underwent HoLEP by the supervising urologist. Each of the 27 procedures was taped and reviewed.Results The mean (range) prostate size was 54.8 (21–122) mL (A.H.) and 61.7 (20.5–172) mL (M.M.E.). The mean operative duration was 98 (50–175) min and the mean enucleation time 68 (29–108) min. The improvements in IPSS, QoL score, Qmax and PVR were highly significant (P < 0.001), with mean values before and after HoLEP of 16.8 and 8.2, 3.1 and 1.4, 7.7 and 20.8 mL/s, and 232 and 41.3 mL, respectively. Of the 27 patients, 23 (85%) were catheter-free on the first day after HoLEP; the mean hospital stay was 1.8 days. All these results were comparable with the results of 118 patients treated by M.M.E. The two most difficult technical steps identified were the initial apical enucleation and the incision of the remaining antero-apical mucosal attachment of the lateral lobes. The operator became adept with the HoLEP technique after a mean of 20 patients.Conclusion HoLEP can be learnt but requires longer training than standard transurethral resection. Extensive experience with transurethral surgery and the supervision of an experienced urologist are prerequisites for success.
BJU International 11/2002; 90(9):863 - 869. · 2.84 Impact Factor
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ABSTRACT: We have previously reported the possible role of the insulin-like growth factor-I (IGF-I) system of mitogens in the development of detrusor smooth muscle hyperplasia and hypertrophy after spinal cord injury. We evaluated the in vivo effects of the anti-growth factor somatostatin analogue octreotide on the IGF-I system as well as subsequent changes in bladder smooth muscle hypertrophy and function after spinal cord injury in rats.
Included in this study were 90 adult female Sprague-Dawley rats weighing 200 to 250 gm. Of the rats 18 served as sham operated controls, while the remaining 72 underwent were spinal cord transection at the level of the T10 vertebra. The spinalized animals were randomly divided into 4 equal groups of 18, of which 1 group served as paraplegic controls. The other 3 groups received octreotide (60 microgram. daily for 4 weeks) delivered via a subcutaneously implanted osmotic pump immediately, 2 and 4 weeks after spinal cord injury. At the end of the experiment (6 to 8 weeks) each group of animals was subdivided into 2 subgroups of 9. In the first group filling cystometrography was done, while in the second subgroup wet bladder weight was estimated and Northern blot analysis was performed.
Mean wet bladder weight plus or minus standard deviation in sham operated and paraplegic controls was 0.11 +/- 0.01 and 0.64 +/- 0.33 gm., respectively (p <0.05). The increase in bladder weight in paraplegic controls was associated with over expression of the IGF-I gene and with marked suppression of IGF binding proteins-3 and 5 compared with sham operated controls. On the other hand, mean wet bladder weight in the animals that received octreotide immediately after spinal cord injury was 0.17 +/- 0.02 gm., which was associated with a dramatic decrease in IGF-I gene expression and increased expression of IGF binding proteins-3 and 5. Mean cystometric bladder capacity in paraplegic controls was 0.48 +/- 0.18 ml. with an associated voiding pressure of 71 +/- 13 cm. water. All paraplegic controls showed detrusor hyperreflexia. In animals that received octreotide immediately after spinal cord injury mean cystometric bladder capacity was 2.49 +/- 1.75 ml. with an associated voiding pressure of 32 +/- 7 cm. water. Detrusor hyperreflexia disappeared in 88.89% of the rats in this group. There were less marked changes in bladder weight (mean 0.24 and 0.29 +/- 0.3 gm.), IGF-I gene expression and its binding proteins and urodynamic parameters when the drug was given 2 and 4 weeks, respectively, after spinal cord injury.
Modulating the IGF-I system of mitogens in detrusor smooth muscle with consequently decreased bladder hypertrophy and improved urodynamic behavior in spinal cord injured animals using somatostatin analogue could be a possible therapeutic modality in patients with spinal cord injury.
The Journal of Urology 09/2002; 168(3):1253-8. · 3.75 Impact Factor
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ABSTRACT: To compare the performance of prostate-specific antigen (PSA), the free/total PSA (F/T PSA) ratio, and complexed PSA (cPSA) in prostate cancer detection.
Five hundred thirty-five patients evaluated at the UROMED prostate cancer detection clinic had total PSA, free PSA, and cPSA measured before undergoing transrectal ultrasonography and sextant prostate biopsies. A direct comparison was performed between the different PSA assays to evaluate their ability to detect prostate cancer.
Of the 535 patients evaluated, 38.1% had prostate cancer detected. The mean age of the entire population was 63.6 years (range 35 to 86). Abnormal digital rectal examination findings were present in 33.4% of the patients. The mean and median values of PSA and cPSA were significantly higher and the F/T PSA ratio was lower in patients with prostate cancer. The F/T PSA ratio performed better than either cPSA or total PSA. A higher specificity was observed with the F/T PSA ratio than with cPSA using either the entire patient population or subsets of patients with PSA levels between 4.0 and 10 ng/mL or 4.0 to 6.0 ng/mL.
The use of the F/T PSA ratio offers improved prostate cancer detection compared with either cPSA or total PSA.
Urology 03/2002; 59(2):261-5. · 2.43 Impact Factor
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ABSTRACT: The use of electrical neural stimulation as treatment for neurogenic bladder is complicated by simultaneous contraction of the striated sphincter. This result is due to the composition of the ventral sacral roots, which contain somatic fibers innervating the external urethral sphincter and preganglionic parasympathetic fibers innervating the detrusor, among others. The somatic fibers have a larger caliber than the parasympathetic fibers and, as large diameter fibers, need a lower stimulus amplitude for activation than smaller fibers. Activation of the smaller fibers is always accompanied by activation of the larger fibers. We studied the effect of chronic application of selective combined low and high frequency current stimulation of the ventral sacral root on bladder evacuation and urethral resistance in chronically spinalized (spinal cord transected above the spinal micturition center) male dogs for daily bladder evacuation.
A total of 14 male mongrel dogs weighing 20 to 25 kg. underwent transection of the spinal cord at the T10 vertebra. The S2 ventral sacral root was wrapped with a bipolar electrode connected to a subcutaneous microstimulator. Daily bladder evacuation by neural stimulation with determination of the voided and residual urine volumes was done for 8 months. The animals were stimulated only with low frequency current during the 1-month spinal shock phase. Selective parameters of combined low frequency stimulation and high frequency blockade currents were subsequently applied for 6 months. For the last study month the animals were again stimulated by low frequency current alone. Bladder and urethral pressure as well as electromyography of the external urethral sphincter and pelvic floor muscles were evaluated monthly. Histopathological testing of the chronically stimulated nerve and external sphincter was performed.
Of the 14 dogs 12 completed the followup study. During the shock phase with the application of low frequency only stimulation the animals voided 26% of mean functional bladder capacity with the early return of detrusor activity. Mean detrusor pressure plus or minus standard error of mean was 76.4 +/- 21.6 cm. water, while mean urethral pressure was 83.6 +/- 16.8 cm. water. During the application of selective combined low and high frequency stimulation 7 animals (58%) evacuated the bladder completely with post-void residual urine less than 10% of mean individual functional bladder capacity and 5 (42%) had mean post-void residual urine less than 20% of mean individual bladder capacity. Mean detrusor pressure was 73.5 +/- 20 cm. water and mean urethral pressure was 44 +/- 7.3 cm. water. There was a 45.19% reduction in the mean electromyography activity of the external sphincter. Stimulation of the dogs for the last month by low frequency current resulted in the voiding of 33% of mean bladder capacity with an increase in mean urethral pressure and electromyography activity.
These results of reducing external sphincter activity by the simultaneous application of high frequency current blockade of the somatic fibers and activation of the autonomic fibers of the bladder by low frequency stimulation are promising.
The Journal of Urology 09/2001; 166(2):728-33. · 3.75 Impact Factor
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ABSTRACT: Spinal cord injury above the sacral micturition center usually leads to detrusor hyperreflexia, increased intravesical pressure and post-void residual urine. Detrusor hyperreflexia is believed to be mediated by afferent C fibers with tachykinins as neurotransmitters. We investigated the selective peptide tachykinin antagonists MEN 11420 and GR 82334 of NK-2 and NK-1 receptors, respectively, in a chronic rat model of detrusor hyperreflexia after suprasacral spinal cord injury.
Adult female Sprague-Dawley rats weighing 200 to 250 gm. were used. The spinal cord was transected at the T10 level. The bladder was evacuated by the Credé maneuver 3 times daily. After 6 weeks the rats were implanted with femoral vein and bladder dome catheters 2 days before filling cystometry. The 5 rats in group 1 received 100 nmol./kg. of the NK-2 antagonist MEN 11420 intravenously. The 5 rats in group 2 received 100 nmol./kg. of the NK-1 antagonist GR 82334 intravenously. The 5 rats in group 3 received a combination of the same dose of each antagonist. Three repetitive micturition cycles were recorded before injection. Three micturition cycles were done 20 minutes after the injection of each antagonist. Mean cystometric parameters were reported, including bladder capacity, micturition pressure, baseline pressure, post-void residual urine and micturition volume, and the number and amplitude of hyperreflexic contractions greater than 15 cm. water.
MEN 11420 significantly reduced the frequency of hyperreflexic contractions and baseline bladder pressure (p <0.05). There was no statistically significant effect on the other cystometric parameters. GR 82334 reduced the amplitude of hyperreflexic contractions but not statistically significant. A combination of MEN 11420 and GR 82334 significantly reduced the frequency and amplitude of hyperreflexic contractions (p <0.05) with no significant effects on other cystometric parameters, although there was a tendency toward increased micturition volume and bladder capacity.
These results suggest that at the peripheral level there is an efferent role of tachykinins in detrusor hyperreflexia after spinal cord injury. NK-1 and NK-2 receptor selective antagonists reduced the frequency and amplitude of hyperreflexic contractions as well as baseline bladder pressure. This finding may lead to potential new therapeutic modalities using selective tachykinins antagonists with other pharmacological agents to combat detrusor hyperreflexia.
The Journal of Urology 05/2001; 165(5):1739-44. · 3.75 Impact Factor
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ABSTRACT: A neural electrical stimulation strategy, intended to recover the bladder functions, is proposed. Restoring urinary functions allows voluntary bladder voiding, and reduces or even suppresses hyperreflexia. The preliminary stimulation system is composed of subcutaneous implantable stimulators (an implant) and an external device. The implant includes the selective stimulation for bladder voiding, in addition to a new permanent stimulation technique to reduce (or cancel) the bladder hyperreflexia and so cures other related diseases. Permanent stimulation is a low frequency, low amplitude and all day long stimulation that needs to be battery powered. On the other hand, selective stimulation is a bi-frequency, punctual, precise and at a higher amplitude stimulation that is well controlled and powered from the outside. Eight prototypes of the stimulator have been used in an experimental evaluation in dogs to characterize the reliability and functionality of the new implant in-a real application environment. Preliminary results of the study show that the proposed stimulation system and the stimulation strategy provide significant improvement for bladder hyperreflexia curing while it confirmed the efficiency of the selective stimulation by means or high frequency blockage.
Engineering in Medicine and Biology Society, 2001. Proceedings of the 23rd Annual International Conference of the IEEE; 02/2001
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S W Siegel,
F Catanzaro,
H E Dijkema, M M Elhilali,
C J Fowler,
J B Gajewski,
M M Hassouna,
R A Janknegt,
U Jonas,
P E van Kerrebroeck,
A A Lycklama a Nijeholt,
K A Oleson,
R A Schmidt
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ABSTRACT: Many patients have chronic, debilitating symptoms of voiding dysfunction that are refractory to conventional medical or surgical therapies. This multicenter, prospective study evaluated the long-term effectiveness of sacral nerve stimulation using the implantable Medtronic InterStim therapy for urinary control in patients with otherwise intractable complaints of urinary urge incontinence, urgency-frequency, or retention. Each patient first underwent temporary, percutaneous sacral nerve test stimulation. If at least a 50% reduction in target symptoms was documented for at least 3 days, patients received a permanent Medtronic InterStim sacral nerve stimulation system that includes a surgically implanted lead and neurostimulator. Regular follow-up was conducted with outcome data. We report here on patients who have been observed from 1.5 to 3 years postimplantation. The results demonstrate that after 3 years, 59% of 41 urinary urge incontinent patients showed greater than 50% reduction in leaking episodes per day with 46% of patients being completely dry. After 2 years, 56% of the urgency-frequency patients showed greater than 50% reduction in voids per day. After 1. 5 years, 70% of 42 retention patients showed greater than 50% reduction in catheter volume per catheterization. We conclude that the Medtronic InterStim therapy for urinary control system is an effective therapy with sustained clinical benefit for patients with intractable symptoms of urinary urge incontinence, urgency-frequency, or retention.
Urology 01/2001; 56(6 Suppl 1):87-91. · 2.43 Impact Factor
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U Jonas,
C J Fowler,
M B Chancellor, M M Elhilali,
M Fall,
J B Gajewski,
V Grünewald,
M M Hassouna,
U Hombergh,
R Janknegt,
P E van Kerrebroeck,
A A Lylcklama a Nijeholt,
S W Siegel,
R A Schmidt
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ABSTRACT: We investigate the efficacy of sacral neurostimulation in patients with idiopathic urinary retention in a prospective, randomized multicenter trial.
A total of 177 patients with urinary retention refractory to standard therapy were enrolled in the study. Greater than 50% improvement in baseline voiding symptoms during a 3 to 7-day percutaneous test stimulation qualified a patient for surgical implantation of an InterStim parallel system. Of the patients who qualified for implantation 37 were randomly assigned to a treatment and 31 to a control group. Patients in the treatment group underwent early surgical implantation of the sacral nerve stimulation system, while implantation was delayed in the control group for 6 months. Followup evaluations, including voiding diary analysis and temporary deactivation of the stimulator at 6 months, were conducted at 1, 3, 6, 12 and 18 months after implantation in the treatment group, and after 3 and 6 months in the control group.
Compared to the control group, patients implanted with the InterStim system had statistically and clinically significant reductions in the catheter volume per catheterization (p <0.0001). Of the patients treated with implants 69% eliminated catheterization at 6 months and an additional 14% had a 50% or greater reduction in catheter volume per catheterization. Therefore, successful results were achieved in 83% of the implant group with retention compared to 9% of the control group at 6 months. Temporary inactivation of sacral nerve stimulation therapy resulted in a significant increase in residual volumes (p <0.0001) but effectiveness of sacral nerve stimulation was sustained through 18 months after implant.
Results of this prospective, randomized clinical study demonstrate that sacral nerve stimulation is effective for restoring voiding in patients with retention who are refractory to other forms of treatment.
The Journal of Urology 01/2001; 165(1):15-9. · 3.75 Impact Factor
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R A Janknegt,
M M Hassouna,
S W Siegel,
R A Schmidt,
J B Gajewski,
D A Rivas, M M Elhilali,
D C Milam,
P E van Kerrebroeck,
H E Dijkema,
A A Lycklama à Nÿeholt,
M Fall,
U Jonas,
F Catanzaro,
C J Fowler,
K A Oleson
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ABSTRACT: To evaluate the long-term efficacy of sacral nerve stimulation for refractory urinary urge incontinence.
Urge incontinent patients qualified for surgical implantation of a neurostimulator system after trial screening with percutaneous test stimulation. Surgical implantation of the InterStim System (Medtronic Inc., Minneapolis, Minn., USA) was performed in cases where a >50% reduction in incontinence symptoms was documented during the 3- to 7-day test stimulation period. The InterStim System consists of an implantable pulse generator, a transforamenally placed quadripolar lead, and an extension that connects these two devices for unilateral stimulation of the S3 or S4 sacral nerve. Efficacy for 96 implanted patients was based on urinary symptom changes as quantified in voiding diaries collected at baseline and annually after surgical implantation.
As compared to baseline, the group of 96 implanted patients demonstrated significant reductions in urge incontinent symptoms at an average of 30.8+/-14.8 (range 12-60) months with respect to the number of urge incontinent episodes per day, severity of leaking, and the number of absorbent pads/diapers replaced per day due to incontinence (all p<0.0001, respectively). Gender, pretreatment variables, and age were not found to be relevant factors that affected these results. 11 of the 96 patients underwent device explant due to lack of efficacy, pain or bowel dysfunction. These data were conservatively included in the efficacy results. No permanent injuries associated with the devices or therapy were reported.
Sacral nerve stimulation is an effective treatment for refractory urge incontinence with sustained long-term benefit through an average of 30.8 months.
European Urology 01/2001; 39(1):101-6. · 8.49 Impact Factor
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ABSTRACT: Among the treatments to enhance the bladder voiding, the sacral roots neurostimulation is one of the most promising techniques. The electrostimulation of sacral nerves provokes a simultaneous contraction of the detrusor muscle as well as the external urethral sphincter (EUS). A new simplified-architecture implantable stimulator with its wireless controller have been designed to investigate high-frequency inhibition stimulation strategies. This innovative technique based on high-frequency inhibition reduces sphincter activity during stimulation. Low-frequency current pulses also applied to the sacral roots induces contraction of the detrusor muscle resulting in low pressure voiding. Chronic experiments were carried out on ten male mongrel paraplegic dogs. One cuff electrode was implanted along with each stimulator for eight months. The animals were stimulated twice a day using the prototypes of our implantable selective stimulator while voided and residual urine volume were measured during the procedure. These experiments revealed that the proposed stimulation strategy enhances bladder voiding by more than 50% in comparison with low-frequency only stimulation. The residual urine volume was reduced to an average of 9% and low pressure micturition was achieved as shown by weekly cystourethrogram.
IEEE Transactions on Rehabilitation Engineering 01/2001; 8(4):464-70.
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M M Hassouna,
S W Siegel,
A A Nÿeholt, M M Elhilali,
P E van Kerrebroeck,
A K Das,
J B Gajewski,
R A Janknegt,
D A Rivas,
H Dijkema,
D F Milam,
K A Oleson,
R A Schmidt
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ABSTRACT: Neuromodulation of sacral nerves has shown promising results in correcting voiding dysfunction. We report the results of a multicenter trial designed to assess the efficacy of sacral nerve neuromodulation in patients presenting with refractory urinary urgency-frequency.
A total of 51 patients from 12 centers underwent baseline assessment, including a detailed voiding diary, urodynamic evaluation and percutaneous test stimulation of the sacral nerves at S3 and/or S4. All patients enrolled in the study had undergone prior conventional treatment, such as pharmacotherapy, hydrodistention and surgical intervention, which failed. All patients demonstrated a satisfactory response to trial stimulation and were randomly divided into a stimulation group (25 patients) and a control group (26). A sacral nerve stimulation device was implanted after 6 months in the control group. Patients were followed at 1, 3 and 6 months, and at 6-month intervals for up to 2 years after implantation of a neuroprosthetic InterStim* system. dagger The study variables included the number of voids daily, volume voided per void and degree of urgency before void.
Compared to the control group, 6-month voiding diary results demonstrated statistically significant improvements (p <0.0001) in the stimulation group with respect to the number voids daily (16.9 +/- 9.7 to 9.3 +/- 5.1), volume per void (118 +/- 74 to 226 +/- 124 ml.) and degree of urgency (rank 2.2 +/- 0.6 to 1.6 +/- 0.9). Patients in the control group showed no significant changes in voiding parameters at 6 months. Significant improvements in favor of the stimulation group were noted in various parameters with respect to water cystometry and quality of life (SF-36). At 6 months after implant, neurostimulators were turned off in the stimulation group and urinary symptoms returned to baseline values. After reactivation of stimulation sustained efficacy was documented at 12 and 24 months.
Neuromodulation of the sacral nerves is an effective, safe therapy that successfully treats significant symptoms of refractory urgency-frequency.
The Journal of Urology 06/2000; 163(6):1849-54. · 3.75 Impact Factor
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ABSTRACT: Smooth muscle cells of the bladder retain the ability to proliferate in response to injury or mechanical stimulation. Insulin-like growth factor (IGF) I is a mitogenic and hypertrophic agent for smooth muscle cells. The purpose of this study is to examine if spinal cord injury could lead to bladder hypertrophy via the IGF system.
The study involved spinal cord transection of female Sprague Dawley rats (approximately 250 to 300 gm.). Six weeks following surgery the urinary bladder was collected. Northern and Western blotting, and IGF-I receptor (IGF-IR) affinity labeling were used to determine the expression of the IGF system, IGFBP levels, and IGF-IR levels respectively.
Chronic spinal cord injury leads to an increase in the wet weight of the bladder and in the level of proliferation cell nuclear antigen expression. IGF-I mRNA levels increase, while IGFBP 3 and 5 mRNA and protein levels dramatically decrease. The gene expression of IGFBP 2 and 4 varies from rat to rat, and IGF-IR expression slightly increases.
Our results suggest that following spinal cord injury, overexpression of IGF-I and underexpression of IGFBP 3 and 5 may lead to hyperplasia of the smooth muscle layer of the bladder.
The Journal of Urology 03/1999; 161(2):699-705. · 3.75 Impact Factor
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ABSTRACT: To assess the 30-day mortality rate and overall survival after radical retropubic prostatectomy (RRP).
Identification of all RRPs performed in the Province of Quebec between January 5, 1988 and January 16, 1996 was accomplished through the Quebec Healthcare Plan Database.
Four thousand nine hundred ninety-seven RRPs were performed by 104 urologists. Overall, 451 deaths were recorded: 32 occurred during the first 30 days (0.6% 30-day mortality rate). A significant decrease in the 30-day mortality rate, from 2.45% to 0.5%, was recorded during the span of the study. The year of surgery, patient age, and hospital type were statistically significant short-term mortality variables (life table analysis). Patient age and year of surgery determined the cumulative survival probability (univariate and multivariate Cox analysis). Cumulative survival at 31 months of follow-up increased from 88.2% in 1988 to 98.1% in 1995. Men 75 years old and older were at a clear disadvantage with regard to survival probability compared with their younger counterparts.
In this population-based analysis of RRP outcomes, we demonstrated a significant improvement in short- and long-term outcomes, as evidenced by a decrease in the 30-day mortality rate and an improved cumulative survival, recorded over the span of the study. The recorded outcome trends may be explained by improved patient selection and optimal management. Although we are unable to determine cancer-specific outcomes, the results of this analysis should prove valuable to urologists and patients until there are results from randomized trials.
Urology 01/1999; 52(6):1041-6. · 2.43 Impact Factor
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ABSTRACT: Detrusor-sphincter dyssynergia is a main problem in supra-sacral spinal cord injured patients. The problem of high pressure voiding is also encountered in most electrically induced micturition because of the mixed somatic and autonomic fiber components of the ventral sacral root. We studied the effect of selective high-frequency blockade at the sacral nerve root in an acute spinalized canine model to prevent the deleterious consequences associated with the elevated bladder outlet resistance. A new functional electrical stimulation system which can generate one signal composed of two independent adjustable current waveforms delivered via a single bipolar electrode was used in 11 dogs. The selectivity resulted from the inhibition of the sphincteric somatic innervation by a high frequency pulse while the low frequency stimuli activated the bladder autonomic fibers. Bladder and urethral pressure as well as electromyograms of external urethral sphincter were recorded to determine whether selective high-frequency blockade occurred. Our experiments showed that we were able to achieve selective blockade of the external urethral sphincter during the simultaneous detrusor stimulation, thus obtaining a more physiologic voiding.
The Journal of Urology 10/1998; 160(3 Pt 1):901-7. · 3.75 Impact Factor
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ABSTRACT: To examine the use of radical retropubic prostatectomy (RRP) in a large population-based study.
Identification of all RRPs performed in the province of Quebec between the years 1988 and 1993 was accomplished by relying on the Quebec Healthcare Plan Database.
Overall, 2861 RRPs have been performed during the study period. On average, 80% of surgeries have been performed by urologists using this surgery 12 times or less annually. Of all surgeries, 420 (15%) RRPs have been performed in individuals 71 years of age or older.
Each year, most RRPs (80%) in this population-based study were performed by urologists performing this procedure 12 times or less annually. A substantial proportion (15%) of RRPs have been performed in men 71 years of age or older, in whom the detriments of radical surgery may outweigh its benefits. These findings could potentially contribute to suboptimal outcomes when radical prostatectomy is compared with alternative treatment modalities.
Urology 09/1998; 52(2):219-23. · 2.43 Impact Factor
