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Biomedical subjects

P B Clark

Publications and source records attributed to P B Clark.

At least 19 recordsLinked to original sources
PubMed1999

Minimally invasive treatment of urinary tract calculi in children.

OBJECTIVE: To report experience of a broad multimodality approach to the treatment of calculi in children using extracorporeal shock wave lithotripsy (ESWL), ureteroscopy/laser lithotripsy, lithoclast and percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: The treatment and outcome were reviewed in 43 children managed by a range of minimally invasive modalities, either singly or in combination, between 1990 and 1997. These patients represent a selected group deemed suitable for minimally invasive management during a period of developing experience with these techniques. Of this cohort, six children had previously undergone open stone surgery and contributory metabolic abnormalities were identified in seven. ESWL was the sole treatment modality in 24 children (56%). In five children (12%) ureteroscopy/laser lithotripsy was combined with ESWL, eight (18%) underwent ureteroscopy/laser lithotripsy alone, whilst three with bladder stones were treated with the lithoclast. Combined therapy including PCNL was required in three patients. RESULTS: Of the 43 children treated, 38 (88%) were rendered stone-free. Metabolic disorders accounted for three of the five cases of residual calculi. Complications requiring intervention occurred in two children (7%) and three subsequently underwent open pyelolithotomy or ureterolithotomy after unsuccessful minimally invasive treatment. CONCLUSIONS: Used selectively, the range of minimally invasive procedures available for adults, including ureteroscopy and PCNL, can be safely and effectively extended to the treatment of urinary tract calculi in children. The role of open surgery will diminish further with the availability of specialized instruments for paediatric PCNL.

Adolescent↗
PubMed1999

The role of ureteral stent placement in the prevention of Steinstrasse.

BACKGROUND AND OBJECTIVE: Steinstrasse constitutes a potentially serious complication of extracorporeal shock-wave lithotripsy (SWL). Ureteral stent placement has been used to prevent Steinstrasse after fragmentation of larger stones. However, particularly more recently, its preventive efficacy has been questioned. The aim of this study therefore was to analyze the role of ureteral stent placement in the prevention of Steinstrasse. METHODS: We analyzed data of 1087 patients who had been treated with a Wolf Piezolith 2300 in the General Infirmary in Leeds/UK for stones ranging from 10 to 95 mm in diameter. RESULTS: The incidence of Steinstrasse was 6.3%. The likelihood was significantly correlated with the stone size and was significantly less in patients with stones >20 mm if a stent had been inserted prior to SWL. Moreover, in these patients, the risk of acute clinical symptoms in the event of Steinstrasse was greatly reduced, and the treatment could be continued safely in the majority of cases (86%). Treatments of the Steinstrasse itself with SWL resulted in its clearance in most of the cases (78%). It was always possible to clear even extended persistent Steinstrasse by laser lithotripsy. CONCLUSION: These results provide a clear indication for the pre-SWL insertion of a ureteral stent in patients with stones >20 mm in diameter. In the event of Steinstrasse, SWL of the collection should be tried before more invasive endourologic procedures are considered.

Adult↗
PubMed1993

Laser lithotripsy with the Candela MDL-2000 LaserTripter.

The Yorkshire Lithotriptor Centre acquired a Candela MDL-2000 LaserTripter and a 7.2F Miniscope in February 1990. We present the results obtained in the first 200 patients referred for treatment of ureteric stones or stone fragments. Of 175 patients who were evaluable, 58 had upper ureteric stones, 41 mid-ureteric and 76 lower ureteric stones. Successful laser fragmentation was achieved in 77% of cases and a further 10% were rendered stone-free by the push-bang technique. Ureterolithotomy was required in 9% and the major complication rate was 4%. Ureteric dilatation was not used. Maximum laser energy was required to break 19% of the stones, but no stone was encountered which could not be broken. Laser lithotripsy with this system is highly effective at all levels of the ureter; it is safe and it complements ultrasound-guided extracorporeal lithotripsy.

Female↗
PubMed1992

Treatment of advanced localised prostatic cancer by orchiectomy, radiotherapy, or combined treatment. A Medical Research Council Study. Urological Cancer Working Party--Subgroup on Prostatic Cancer.

A total of 277 patients with apparently localised prostatic cancer (T2-T4 NXMO) were allocated at random to receive radiotherapy alone (88), orchiectomy alone (90) and combined therapy (99) between 1980 and 1985. The main outcome measures were survival, time to appearance of metastases and treatment of local disease progression by further transurethral resection. Orchiectomy, whether alone or with radiotherapy, produced a significant delay in detection of metastases when compared with radiotherapy alone. There were no statistically significant differences between the 3 treatment groups in local disease control or in overall survival.

Combined Modality Therapy↗
PubMed1987

Centenary of the first prostatectomy in Britain.

The first suprapubic prostatectomy in Britain was performed in the General Infirmary at Leeds on 24 March 1887 by Arthur Fergusson McGill. During 1887 six other prostatectomies were performed by McGill and his colleagues. Before he died in 1890 McGill had performed complete enucleation of an adenomatous prostate.

England↗
PubMed1985

Long-term results of two-stage urethroplasty.

Forty-two patients undergoing a two-stage urethroplasty for stricture were reviewed and the long-term sequelae of 30 patients followed up for a minimum period of 1 year (mean 6.3, range 1-14) are presented. Twenty-six patients (87%) were considerably improved, with only minor or no symptoms. Three patients (10%) continued to require treatment for urethral stone or recurrence of stricture and one patient was incontinent. The stricture was eradicated in 28 patients (93%). The late sequelae showed that perineal fistula may not develop until 2 years after the second-stage repair, urethral stone formation until 8 years and recurrence of stricture until 12 years after the second stage. This late onset of sequelae emphasises the importance of long-term follow-up in these patients.

Adult↗
PubMed1985

Malignant hypertension in general practice.

A diagnosis of malignant hypertension was recorded for 165 patients in the national morbidity study between 1970 and 1973. Three patients with benign hypertension were selected as age- and sex-matched controls for each case. The general practitioners in the study were asked to complete a further questionnaire about the patients and 66% of the practices agreed to take part. Information about the retinal findings for the patients was requested and less than half of those in the national morbidity study proved to have a strict diagnosis of accelerated or malignant hypertension although they were originally recorded as patients with malignant hypertension. Of those patients originally classified as having benign hypertension 5% had the retinal appearance of accelerated or malignant hypertension.Patients had been diagnosed as having hypertension for a mean of more than five years prior to entry into the national morbidity study and the survival of patients with both benign and accelerated or malignant hypertension was good. Thirtyfour per cent of those with confirmed benign hypertension and 62% of those with definite accelerated or malignant hypertension died in the follow-up period which was on average 10 years from entry into the national morbidity study.The survival of patients registered with doctors who did not collaborate and of patients whose clinical details were missing was similar to the survival of patients for whom full details were provided.Blood pressure control was only fair with a mean of 172/101 mmHg for the group with benign hypertension and 177/107 mmHg for the group with accelerated or malignant hypertension. Blood pressure control was the poorest for those who died from a stroke. A high proportion (78%) of deaths in association with accelerated or malignant hypertension were from cardiovascular or renal causes.

Aged↗
PubMed1984

Urethral carcinoma after cystectomy: the case for routine urethrectomy.

Eight out of 73 men developed urethral carcinoma after cystectomy and died within 26 months. Of the patients at risk, the calculated incidence of urethral tumour was 2.7 per cent per annum. Prophylactic urethrectomy is recommended for all patients having cystectomy for carcinoma, whatever type of tumour they have. In men without urethral involvement it may be delayed until they have recovered fully from cystectomy. The whole length of the urethra should always be removed, including the fossa navicularis.

Carcinoma in Situ↗
PubMed1980

Vesical leucoplakia.

The clinical and pathological features of vesical leucoplakia are described. The aetiology of leucoplakia is unknown, its treatment is unsatisfactory, and it may be impossible to diagnose malignant change early enough to cure the patient by cystectomy. Prophylactic cystectomy is therefore indicated for patients of either sex with extensive vesical leucoplakia.

Adult↗
PubMed1979

End-to-end ureteroileal anastomosis for ileal conduits.

In the "Y" anastomosis, both ureters are spatulated and joined together to form a single tube which is anastomosed to the proximal end of the ileum. This technique has several theoretical advantages which appear to be borne out in practice when the results of its use in 101 patients followed for up to 12 years are reviewed. Only 2 anastomotic leaks needed operative treatment and only 4 patients developed ureteroileal stenosis. Renal function remained unchanged or improved in 84% of the patients, and definite hydronephorsis or pyelonephritis developed in only 4% of the kidneys. These results show that this method of ureteroileal anastomosis is at least as good as, and possibly better than, other techniques.

Adolescent↗
PubMed1979

Should recurrent calcium oxalate stone formers become vegetarians?

The hypothesis that the incidence of calcium stone disease is related to the consumption of animal protein has been examined. Within the male population, recurrent idiopathic stone formers consumed more animal protein than did normal subjects. Single stone formers had animal protein intakes intermediate between those of normal men and those of recurrent stone formers. A high animal protein intake caused a significant increase in the urinary excretion of calcium, oxalate and uric acid, 3 of the 6 main urinary risk factors for calcium stone formation. The overall relative probability of forming stones, calculated from the combination of the 6 main urinary risk factors, was markedly increased by a high animal protein diet. Conversely, a low animal protein intake, such as taken by vegetarians, was associated with a low excretion of calcium, oxalate and uric acid and a low relative probability of forming stones.

Calcium↗
PubMed1978

Risk factors in calcium stone disease of the urinary tract.

The concept that calcium stone formation may be explained on the basis of a number of risk factors is developed. The main risk factors involved are shown to be calcium, oxalate, pH, acid mucopolysaccharides and uric acid. A method is described for calculating and combining the individual risk factors into a measure of the "relative probability" of forming stones (PSF). PSF values are generally lower in normal subjects than in stone-formers. Amongst the normals, PSF values are lower in children and women than in men. Recurrent stone-formers have the highest PSF values and these correlate well with the severity of the diseases as defined by the stone episode rate of the patient. Single stone-formers have PSF values intermediate between those of normal men and those of recurrent stone-formers.

Adult↗
PubMed1978

Radical cystectomy for carcinoma of the bladder.

A personal series of 50 radical cystectomies has been reviewed to decide whether it is a justifiable operation and, if so, when it should be performed. In spite of the fact that radical cystectomy had a higher operative mortality than simple cystectomy and was sometimes followed by lymphoedema, in patients with invaded iliac lymph nodes it was followed by a 25% 5-year survival. It appears, therefore, to be a justifiable procedure. It is recommended that simple cystectomy should be performed for patients with papillomatosis, carcinoma in situ, and as a salvage procedure after radiotherapy has failed, and that radical cystectomy should be reserved for elective cases in of invasive vesical tumours, and for those patients who are found at exploration to have obvious metastic deposits in the iliac lymph nodes.

Adult↗
PubMed1978

Urethral tumours.

A series of 33 patients with urethral tumours has been studied to assess the risk of dissemination by endoscopic diathermy. This risk is less than that of cystourethrectomy. Urethral tumours should be treated like the vesical tumours they follow and so closely resemble: by endoscopic treatment while they remain small, sparse and superficial; by cystourethrectomy as soon as they become larger and more extensive. Recurrence of tumour in the urethral stump following cystectomy should always be treated by urethrectomy.

Aged↗