Biomedical subjects
Publications and source records attributed to B E Erlandson.
A 71-year-old man was treated with transurethral microwave thermotherapy because of symptoms of benign prostatic hyperplasia. The treatment session was performed without any abnormal complaints from the patient. Two hours post-treatment the patient felt pain in his penile shaft and noticed a wound. A thorough investigation revealed that the only possible explanation for the injury was a dislocation of the catheter.
In 1977, a new phase began in hearing rehabilitation of patients with chronic middle and external diseases and atresias. Thus far, these patients have had to rely on conventional bone conduction and air conduction devices that for various reasons give poor rehabilitation. The principle of the new treatment, made possible by the Swedish bone-anchored hearing system, is simple: sound vibrations are directly transmitted to the skull bone via a skin-penetrating titanium implant and then are further transmitted to the cochlea, bypassing the middle ear. The present paper summarizes our results in 147 patients over 10 years, including a total of 6,334 follow-up months. No significant rate of skin infections was observed. In over 93% of the observations, no sign of adverse skin reaction was seen. When herein-suggested indications for treatment with the bone-anchored sound processor HC-200 are followed, the success rate is over 90%. The improved quality of life reported by the patients is a combination of improved quality of sound, improved comfort, and relief from middle ear and ear canal disease occasioned by conventional hearing aids.
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The clinical efficacy of a new device for treatment of female incontinence was studied in a multicenter trial. The device consists of an inflatable electrode carrier and an external stimulator unit. Forty women were treated: 10 had primary or recurrent genuine stress incontinence, 15 had urge incontinence due to idiopathic detrusor instability, not responding to drug treatment, and 15 had stress incontinence combined with detrusor instability. Twenty-five patients were improved by the treatment. Another 8 reported an excellent result of treatment and remained free of symptoms for more than six months after withdrawal of the treatment. The results were more favorable in patients with bladder hyperactivity than in genuine stress incontinence. The patients' general ratings of treatment efficacy correlated well with their recordings of urinary frequency and consumption of incontinence pads. The functional bladder capacity increased in improved patients, but normalization of urodynamic parameters was no prerequisite for clinical improvement. We found intravaginal electrical stimulation to be a valuable alternative to medical and surgical intervention in patients with detrusor instability.
Efferent nerve activity was recorded from pelvic nerve filaments to the urinary bladder of the cat. At intravesical pressures below 5-7 cm H2O there was no activity, but at higher pressure levels the parasympathetic neurones discharged in 10- to 15-second-long rhythmic bursts separated by silent periods. The frequency of the burst varied from about 1/min at 5 cm H2O to 6-7/min at 15-20 cm H2O. Each burst of activity was followed by a small bladder contraction. The nervous activity preceded the contraction by several seconds, indicating that the bladder response was caused by the efferent discharge. Prolonged continuous efferent activity could occur immediately after pressure changes, at pressures above 20-25 cm H2O or after inhibition caused by intravaginal stimulation. In these situations, rhythmic activity resumed as inhibition of the tonic discharge. This behaviour indicates that the rhythmicity is primarily determined by a central inhibitory mechanism. The findings are discussed in relation to the normal function of the neuronal feedback systems of the bladder and their possible role in the development of the clinical condition 'unstable bladder'.
In a follow-up study the accuracy of a simple preoperative screening including history, Bonney 's test and supine cystometry was evaluated in patients with stress urinary incontinence. Based upon preoperative history alone, the patients were divided into two different groups, pure stress incontinence, and mixed stress and urge incontinence. All patients accepted had a normal supine cystometry at the preoperative work-up. The results of the operation were good in pure stress incontinence. In patients with mixed stress and urge incontinence the results were unsatisfactory and most of them presented a variety of urodynamic abnormalities postoperatively. Thus, in patients with pure stress incontinence, acceptance for surgery may be based upon a careful history, a simple supine cystometry and Bonney 's test, but in patients with mixed stress and urge incontinence a comprehensive clinical and urodynamic evaluation is mandatory. It seems that combination of detrusor instability and a history of pronounced urgency preoperatively calls for other therapeutic alternatives than operation.
As part of a project aimed at developing a method for accurate evaluation of the position and significance of infravesical outflow obstructions, a technique for recording urethral pressure profiles during flow in male patients was tested in a rigid bladder-urethral model. The catheter which proved to give the most accurate recording of the static pressure in the urethral model had a measuring eye about 250 mm from the tip. With this arrangement, the tip of the catheter did not leave the bladder until the measuring eye had passed the whole length of the urethra and the effective diameter of the urethra and the flow did not change during the recording. The pressure profiles for the different urethral models closely resembled the theoretically calculated curves. Furthermore, the constant recording conditions made it possible to compensate for the influence of the measuring catheter and to calculate the "true" diameter as well as the "true" resistance in different segments of the models.
The micturitional urethral pressure profile (MUPP) was recorded using a measuring catheter with two eyes, 250 mm apart, one for recording the bladder pressure, the other for the urethral pressure during continuous withdrawal during micturition. Fifteen normal male subjects and 48 male patients with infravesical obstruction were studied. By means of the MUPP, it was possible to determine whether the patient had an obstruction or not, to differentiate between various kinds of obstructions and to localise the obstruction in the urethra. Provided infravesical obstructions can be considered "near rigid" segments, the degree of obstruction can be calculated and expressed in terms of a diameter and an approximate resistance. The diameter and resistance values should, however, not be considered alone but be regarded as complementary to the pressure profile.
Intravaginal electrical stimulation (IVS) induces a profound bladder inhibition and is successful in the treatment of incontinence due to detrusor instability. In this experimental study in cats, direct recordings of the efferent activity in thin hypogastric and pelvic nerve filaments to the bladder were used to analyze the neuronal mechanisms underlying this bladder inhibition. A longlasting reflex discharge, with a latency of 35 to 50 msec., was evoked in the hypogastric nerve by IVS. The reflex discharge was unaffected by imposed changes in intravesical pressure or by micturition contractions, but the response was very frequency-sensitive with an optimal transmission at about 5 Hz of stimulation. A "spontaneous" efferent activity could be recorded in the pelvic nerve filaments when the bladder pressure was elevated above 5 to 7 cm. H2O. The pelvic activity occurred in 10 to 20-second bursts, each followed by an abortive detrusor contraction. IVS of 5 to 10 Hz completely abolished this efferent pelvic activity by central inhibition. The findings are discussed in relation to the normal neuronal control of the bladder and to the clinical application of IVS.
Bipolar electrocoagulation has previously been shown to give a considerable amount of current leakage to ground from either of the two outputs. This might result in unwanted tissue destruction. Thus far, no standard has been proposed for current leakage to ground from the outputs of bipolar equipment. This study was performed to establish safe parameters for such leakage. To determine the limit for damage-no damage, monopolar stimulations were performed on the brain surface of dogs. Blood-brain barrier disturbance was used as an indicator of damage. The limit for acceptable current leakage was found to be about 10 to 15 mA. Most bipolar coagulators were found to exceed this value. The electrical data recorded in this study should be considered in the design of bipolar equipment for electrocoagulation.
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We treated 14 women with chronic interstitial cystitis with long-term intravaginal or transcutaneous nerve stimulation. Clinical and urodynamic evaluations were done after 6 months to 2 years. Improvement was not immediate but required a considerable period of continuous, daily use of electrical stimulation. The results were favorable--a substantial decrease in pain and frequency of micturition in all patients after long-term treatment. Since the methods seem effective and are simple, cheap and non-destructive electrical stimulation is recommended for all patients with chronic interstitial cystitis.
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Clinical observations have indicated that not only stress incontinence due to defective urethral closure but also urge incontinence due to bladder hyperactivity can be successfully treated by electrical stimulation of the pelvic floor. Clinical investigations revealed that intravaginal electrical stimulation caused bladder inhibition registered as a volume increase. This inhibition was most marked at a low stimulation frequency (10 Hz). Animal experiments indicated that the bladder inhibition was achieved by autonomic spinal reflex mechanisms activated by stimulation of pudendal afferents.
Intravaginal electrical stimulation (IVS) in cats caused urethral closure and bladder inhibition. The aim was to ascertain the electrical parameters most appropriate for these effects. Minimum voltage was used as main criterion to select an effective, non-destructive stimulation when the shape, frequency and duration of the pulses were systematically varied. Urethral closure was achieved at minimum voltage (3 V) with alternating pulses at a frequency of 50 Hz and a pulse duration of 1.5 ms. Corresponding optimal parameters for bladder inhibition were: alternating pulses, 10 Hz and 1.5 ms. Minimum voltage was 1 V. Moreover, the positions of the electrodes were of significance for the responses. The clinical implications of these findings are that: 1)more differentiated treatment of incontinence could be achieved by adapting the stimulation parameters to the cause of incontinence, and 2) specific electrode positions would probably give optimal responses.