Finite element modeling and in vivo analysis of electrode configurations for selective stimulation of pudendal afferent fibers

<p>Abstract</p> <p>Background</p> <p>Intraurethral electrical stimulation (IES) of pudendal afferent nerve fibers can evoke both excitatory and inhibitory bladder reflexes in cats. These pudendovesical reflexes are a potential substrate for restoring bladder function in persons with spinal cord injury or other neurological disorders. However, the complex distribution of pudendal afferent fibers along the lower urinary tract presents a challenge when trying to determine the optimal geometry and position of IES electrodes for evoking these reflexes. This study aimed to determine the optimal intraurethral electrode configuration(s) and locations for selectively activating targeted pudendal afferents to aid future preclinical and clinical investigations.</p> <p>Methods</p> <p>A finite element model (FEM) of the male cat urethra and surrounding structures was generated to simulate IES with a variety of electrode configurations and locations. The activating functions (AFs) along pudendal afferent branches innervating the cat urethra were determined. Additionally, the thresholds for activation of pudendal afferent branches were measured in α-chloralose anesthetized cats.</p> <p>Results</p> <p>Maximum AFs evoked by intraurethral stimulation in the FEM and in vivo threshold intensities were dependent on stimulation location and electrode configuration.</p> <p>Conclusions</p> <p>A ring electrode configuration is ideal for IES. Stimulation near the urethral meatus or prostate can activate the pudendal afferent fibers at the lowest intensities, and allowed selective activation of the dorsal penile nerve or cranial sensory nerve, respectively. Electrode location was a more important factor than electrode configuration for determining stimulation threshold intensity and nerve selectivity.</p

Cryptococcal Small-Bowel Obstruction in an Hiv-Positive Patient

Meningitis and pulmonary infections are common manifestations of cryptococcosis but gastrointestinal involvement is rare. </jats:p

Randomized clinical trial of sutured <i>versus</i> stapled closed haemorrhoidectomy

Abstract Background Stapled haemorrhoidectomy does not involve dissection, with its attendant potential morbidity, required to perform closed haemorrhoidectomy. This study compared haemorrhoidectomy with (sutured) and without (stapled) preliminary dissection. Methods Forty patients with prolapsed symptomatic haemorrhoids were randomly assigned to sutured (n = 20) or stapled (n = 20) haemorrhoidectomy. Preoperative assessment was by proctoscopy, sigmoidoscopy and anal manometry. Stapled and diathermy haemorrhoidectomies with wound suture were performed, and excised tissue was examined histologically. Pain scores, complications, wound healing and patient satisfaction were recorded. Follow-up was weekly for 4 weeks, and at 3 and 6 months; anal manometry was repeated at the last two visits. Results Postoperative resting and squeeze pressures were reduced by the stapled method at 3 months (P = 0·02 and P = 0·03 respectively), returning to baseline by 6 months. Stapled haemorrhoidectomy was quicker but initial access into the anus was hampered by the bulky stapler. Isolated muscle fibres were identified equally in both groups, but incontinence did not occur. The stapled technique resulted in less postoperative pain (P = 0·04), a greater degree of satisfaction (P = 0·01) and faster wound healing (P &amp;lt; 0·001), but was more expensive. There was no significant difference in complications. Conclusion Despite the higher cost and difficult access, stapled haemorhoidectomy results in less postoperative pain, faster wound healing and greater patient satisfaction than the sutured technique. </jats:sec

Patient perceptions of MRSA.

Drug-resistant nosocomial infections are an increasing problem. This issue has received considerable media coverage. To our knowledge there have been no studies investigating patient awareness and perceptions of nosocomial infections. A total of 113 surgical out-patients completed a questionnaire stating whether they had heard of either superbugs or MRSA. A series of questions were asked about the source of any information; methods of transmission and prevention; the consequences of infection and their emotional response if they were to acquire MRSA. Fifty patients (44%) had heard of superbugs or MRSA mainly via the media (58%) or from hospital staff (44%). The majority would feel either angry or afraid if they acquired MRSA in hospital, but there was good awareness of both methods of infection control and the consequences of infection. From our study, we conclude that the media is at least as important as health professionals in providing information. Concerns regarding nosocomial infection may need to be addressed prior to admission