D.F.M. Thomas

Leeds Teaching Hospitals NHS Trust, Leeds, England, United Kingdom

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Publications (44)97.55 Total impact

  • D. F. M. Thomas
    Journal of Pediatric Urology 02/2011; 7(1):101-101. DOI:10.1016/j.jpurol.2010.09.014 · 1.41 Impact Factor
  • D F M Thomas
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    ABSTRACT: Although prenatal diagnosis has been a prominent feature of Paediatric Urology for more than two decades the published literature has been largely characterized by studies reporting short to medium-term follow up. This deficiency is now being addressed by the growing availability of published and unpublished long-term outcome data for a range of prenatally detected anomalies. This review analyses the evidence on long-term outcomes which is provided by studies with mean or median follow- up exceeding 5 years, with particular emphasis on the small number of studies reporting follow -up at 10 years and beyond. The natural history and outcome of conservatively managed uropathies is considered in conjunction with an appraisal of evidence- based indications for surgical intervention. This review evaluates the relative benefits and drawbacks of prenatal diagnosis for children and their parents and also considers the impact of prenatal diagnosis on the delivery of Paediatric Urological services and specialist training.
    Journal of pediatric urology 03/2010; 6(3):204-11. DOI:10.1016/j.jpurol.2010.01.013 · 1.41 Impact Factor
  • D.F.M. THOMAS
    BJU International 11/2008; 66(3):225 - 231. DOI:10.1111/j.1464-410X.1990.tb14917.x · 3.13 Impact Factor
  • D F M Thomas
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    ABSTRACT: The long-term outcomes of prenatally detected uropathies are poorly documented. Limited data on fetal intervention show a possible reduction in early mortality from pulmonary hypoplasia, but no beneficial effect on long-term prognosis for renal function. Prenatally detected vesicoureteric reflux (VUR) is characterised by males with high-grade primary reflux, who are at long-term risk of renal impairment. Prenatal diagnosis and surgical intervention have contributed to a reduction in long-term morbidity in children with pelviureteric junction (PUJ) obstruction. By the same token, many children have almost certainly undergone unnecessary early pyeloplasty for an obstruction that would have resolved spontaneously. Multicystic dysplastic kidney (MCDK) carries a low (1%) risk of hypertension in childhood. The limited evidence on the long-term outcome of mild dilatation (pelvicaliectasis) indicates this is a largely innocent finding, which carries no increased risk of morbidity.
    Seminars in Fetal and Neonatal Medicine 07/2008; 13(3):189-95. DOI:10.1016/j.siny.2007.10.003 · 3.13 Impact Factor
  • European Urology Supplements 03/2008; 7(3):180-180. DOI:10.1016/S1569-9056(08)60436-4 · 3.37 Impact Factor
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    D F M Thomas
    BJU International 06/2004; 93 Suppl 3:47-50. DOI:10.1111/j.1464-410X.2004.04709.x · 3.13 Impact Factor
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    ABSTRACT: To study the outcome of composite cystoplasty using cultured urothelial cells combined with de-epithelialized colon or uterus in a porcine surgical model, using appropriate controls, and to characterize the neo-epithelium created by composite cystoplasty. Urothelial cells were isolated and propagated in vitro from open bladder biopsies taken from nine female minipigs. Cohesive sheets of confluent urothelial cells were transferred to polyglactin carrier meshes and sutured to de-epithelialized autologous colon in four animals and de-epithelialized autologous uterus in five. These composite segments were then used for augmentation cystoplasty. Conventional colocystoplasty, de-epithelialized colocystoplasty and sham operations were carried out in six control animals. After killing the animals at approximately 90 days the bladders were removed for examination and immunohistochemical analysis, using a panel of antibodies against cytokeratins and urothelial differentiation-associated antigens. Macroscopically, the bladders augmented with composite segments derived from uterine muscle had no evidence of shrinkage or contracture. Histological analysis showed that in four of five composite uterocystoplasties, the neo-urothelium was stratified and had a transitional morphology, although in some areas coverage was incomplete. Immunohistochemical analysis showed evidence of squamous differentiation in both native and augmented segments. All composite and de-epithelialized colonic segments showed significant contraction with poor urothelial coverage, reflecting the unsuitability of the thin-walled porcine colon for de-epithelialization. The functional and macroscopic outcome of bladder augmentation with a composite derived from cultured urothelium and de-epithelialized smooth muscle of uterine origin endorses the feasibility of composite cystoplasty.
    BJU International 04/2004; 93(4):609-16. DOI:10.1111/j.1464-410X.2003.04675.x · 3.13 Impact Factor
  • D.F.M. Thomas
    BJU International 04/2004; 93(4):470-3. DOI:10.1111/j.1464-410X.2003.04653.x · 3.13 Impact Factor
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    W R Cross, D F M Thomas, J Southgate
    BJU International 08/2003; 92(2):165-71. DOI:10.1046/j.1464-410X.2003.04280.x · 3.13 Impact Factor
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    ABSTRACT: Surgical reconstruction of the urinary bladder is performed on patients of all ages for a diverse range of conditions, including congenital abnormalities, bladder dysfunction, trauma and cancer. The most common material utilized to augment or replace the bladder during these procedures is a segment of the patient's own intestine. However, this procedure ('enterocytoplasty') is associated with significant clinical complications that arise due to the exposure of the epithelial lining of the intestine to urine. A number of alternative approaches are being actively developed to find a practical and functional substitute for native bladder tissue. These range from 'composite enterocystoplasty', where the de-epithelialized intestine wall is lined with bladder epithelial cells that have been propagated in vitro, to augmenting the urinary system with natural or synthetic biomaterials that may incorporate in vitro-propagated cells. However, if tissue-engineered products are to have therapeutic application in bladder reconstruction, a number of issues remain to be addressed; these issues are discussed briefly below.
    Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine 02/2003; 217(4):311-6. DOI:10.1243/095441103322060776 · 1.14 Impact Factor
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    ABSTRACT: We document the inheritance pattern of multicystic dysplastic kidney in 3 affected families and screen first-degree relatives of a cohort of children with prenatally detected multicystic dysplastic kidney for renal anomalies. The study also afforded an opportunity to document the natural history of prenatally detected multicystic dysplastic kidney. We identified 3 families during clinical treatment of children with prenatally detected multicystic dysplastic kidneys. Other members of these families were evaluated with renal ultrasonography. For the family screening study index cases were identified from a fetal uropathy database. A total of 94 first-degree relatives (52 parents, 35 full siblings and 7 half siblings) of 29 children with prenatally detected multicystic dysplastic kidneys were studied with urinary tract ultrasonography, blood pressure measurement, urinalysis and plasma biochemistry. Two families had affected sibling pairs, 1 of which also had a half sibling with vesicoureteral reflux. The third family included 3 individuals with multicystic dysplastic kidney and 1 with renal agenesis thought to have resulted from involution of multicystic dysplastic kidney. This family is consistent with autosomal dominant inheritance with variable expressivity and reduced penetrance. In the screening study ultrasonography did not demonstrate significant renal anomalies in any of the 94 first-degree relatives of the multicystic dysplastic kidney index cases. Followup assessment of prenatally detected multicystic dysplastic kidneys in index cases demonstrated total involution in 52% at a median age of 6.5 years with no multicystic dysplastic kidney related morbidity. Multicystic dysplastic kidney can be familial but is most commonly a sporadic anomaly. Formal screening of relatives is not recommended. Followup data on a cohort of children with prenatally detected multicystic dysplastic kidney add further support to conservative management.
    The Journal of Urology 03/2002; 167(2 Pt 1):666-9. DOI:10.1016/S0022-5347(01)69120-1 · 3.75 Impact Factor
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    D. F. M. Thomas
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    ABSTRACT: The prenatal detection of urinary tract anomalies is changing paediatric practice but in many areas the impact on clinical outcome remains difficult to quantify. However it is already apparent that termination of pregnancy has reduced the numbers of infants with lethal pulmonary hypoplasia and renal dysplasia who would previously have been liveborn but destined to succumb as neonates. Similarly, referrals of major non lethal abnormalities such as bladder exstrophy are declining as parents increasingly opt for termination. Fetuses at greatest risk of early onset postnatal renal failure can now be identified with considerable accuracy on prenatal ultrasound. Termination, prompted by quality of life considerations, could result in reduced numbers of infants and young children requiring end stage renal failure treatment in the first few years of life. Pre natal detection of anomalies such as PUJ obstruction and reflux undoubtedly provides an opportunity to avert functional deterioration and minimise urinary infection. But the proportion of children who genuinely benefit has proved difficult to assess. The prenatal detection of mild dilatation is of doubtful benefit in all but a minority of cases. Clinically significant underlying pathology is rare yet this common prenatal finding often generates disproportionate parental anxiety.
    Prenatal Diagnosis 11/2001; 21(11):1004-11. DOI:10.1002/pd.210 · 3.27 Impact Factor
  • D.F.M. Thomas, M Fraser
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    ABSTRACT: To document the current role of adult urologists in the care of children in the UK and to consider the future provision of urological services for children within the context of published national guidelines. A detailed postal questionnaire was sent to all 416 consultant urologists listed as full members of the British Association of Urological Surgeons and resident in the UK. The range of information sought from each urologist included details of personal paediatric training, scope of personal practice, and information about facilities and provision of urological services for children in their base National Health Service hospital. The response rate was 69%; most consultant urologists (87%) in District General Hospitals (DGHs) undertake paediatric urology, mainly routine procedures of minor or intermediate complexity. Of urologists in teaching hospitals, 32% treat children but their involvement is largely collaborative. Consultants appointed within the last 10 years are less willing to undertake procedures such as ureteric reimplantation or pyeloplasty than those in post for > or = 10 years. Currently, 18% of DGH urologists hold dedicated children's outpatient clinics and 34% have dedicated paediatric day-case operating lists. Almost all urologists practise in National Health Service hospitals which meet existing national guidelines on the provision of inpatient surgical care for children. Urologists practising in DGHs will retain an important role as providers of routine urological services for children. However, the tendency for recently appointed consultants to limit their practice to the more routine aspects of children's urology is likely to increase. Training and intercollegiate assessment should focus on the practical management of the conditions most commonly encountered in DGH practice. The implementation of national guidelines may require greater paediatric subspecialization at DGH level to ensure that urologists treating children have a paediatric workload of sufficient volume to maintain a high degree of surgical competence.
    BJU International 08/2001; 88(1):80-3. DOI:10.1046/j.1464-410x.2001.02245.x · 3.13 Impact Factor
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    ABSTRACT: Reconstruction of the urinary bladder with bowel to restore storage capacity is associated with significant complications arising from substituting an absorptive, mucus-producing intestinal epithelium for the barrier urothelium of the bladder. To overcome these problems, we are developing a "composite enterocystoplasty" procedure to replace the epithelium of the bowel with autologous in vitro-propagated normal urothelial cells. The aims of this study were to evaluate synthetic biomaterials as delivery vehicles for the cultured urothelial cells and provide support during transfer and cell adherence to the de-epithelialized bowel wall. The surgical compliance of 12 biomaterials was evaluated, along with their ability to support urothelial cell attachment. Transfer of urothelial cells onto biomaterials as single cell suspensions or intact cell sheets was investigated. Seeding of a single cell suspension on to non-woven mesh resulted in poor cell attachment. Seeding onto woven mesh was more efficient, but the most effective transfer method involved producing an intact cell sheet that could be combined with woven, knitted and non-woven biomaterials. Transfer of the cell sheet : mesh complexes onto a de-epithelialized bladder stroma produced a stratified epithelium incorporating the strands of the mesh and expressing urothelial-associated antigens after 48 h in organ culture. Thus, we have developed and evaluated a suitable transfer method for in vitro propagated urothelial cells to be used in "composite enterocystoplasty".
    Journal of Materials Science Materials in Medicine 01/2001; 12(10-12):991-6. DOI:10.1023/A:1012869318205 · 2.38 Impact Factor
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    ABSTRACT: 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). 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. 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. 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.
    BJU International 09/1999; 84(3):339-42. DOI:10.1046/j.1464-410x.1999.00166.x · 3.13 Impact Factor
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    ABSTRACT: We document the postpubertal outcome of feminizing genitoplasty. A total of 14 girls, mean age 13.1 years, with congenital adrenal hyperplasia were assessed under anesthesia by a pediatric urologist, plastic/reconstructive surgeon and gynecologist. Of these patients 13 had previously undergone feminizing genitoplasty in early childhood at 4 different specialist centers in the United Kingdom. The outcome of clitoral surgery was unsatisfactory (clitoral atrophy or prominent glans) in 6 girls, including 3 whose genitoplasty had been performed by 3 different specialist pediatric urologists. Additional vaginal surgery was necessary for normal comfortable intercourse in 13 patients. Fibrosis and scarring were most evident in those who had undergone aggressive attempts at vaginal reconstruction in infancy. These disappointing results, even in the hands of specialists, highlight the importance of late followup and challenge the prevailing assumption that total correction can be achieved with a single stage operation in infancy. Although simple exteriorization of a low vagina can reasonably be combined with cosmetic correction of virilized external genitalia in infancy, we now believe that in some cases it may be best to defer definitive reconstruction of the intermediate or high vagina until after puberty. The psychological issues surrounding sexuality in these patients are inadequately researched and poorly understood.
    The Journal of Urology 06/1999; 161(5):1588-91. DOI:10.1016/S0022-5347(05)68986-0 · 3.75 Impact Factor
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    ABSTRACT: We established a 3-dimensional organ culture model of urinary tract tissue in which to study the effects of seeding cultured urothelial cells onto de-epithelialized urothelial stroma. Normal human urinary tract tissues were placed in organ culture or used to establish urothelial cell cultures. At passage 2 cell cultures were harvested and used to reconstitute autologous organ cultures by seeding onto de-epithelialized stroma. Organ cultures were harvested at intervals and analyzed by immunohistology with a panel of antibodies against differentiation associated antigens, cytokeratins, cell adhesion molecules, extracellular matrix components and proliferation associated antigens. Human urothelial tissues were maintained in organ culture for at least 18 weeks and they retained a transitional epithelial morphology with expression of normal in situ antigenic characteristics. Within 2 weeks of reconstitution recombined organ cultures formed a stratified, polarized, transitional-like neo-epithelium that expressed many of the phenotypic and differentiated characteristics of normal tissue. Basement membrane formed at sites of direct contact between urothelial cells and stroma. After an initial stabilization period the proliferation rate of the urothelium of intact and reconstituted organ cultures decreased to the low turnover rate characteristic of normal urothelium in situ, indicating that the cells were responsive to normal growth regulatory controls. Normal human urothelial cells, which express a proliferative nondifferentiated phenotype in monolayer culture, retain the capacity to differentiate and reform a slow turnover, stratified transitional epithelium.
    The Journal of Urology 10/1997; 158(3 Pt 2):1147-52. DOI:10.1097/00005392-199709000-00115 · 3.75 Impact Factor
  • The Journal of Urology 09/1997; 158(6). DOI:10.1097/00005392-199709000-00116 · 3.75 Impact Factor
  • K Lakhoo, D.F.M. Thomas, M Fuenfer, A J D'Cruz
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    ABSTRACT: To analyse the reasons underlying the failure of routine pre-natal ultrasonography to prevent the subsequent development of urinary tract infection (UTI) in children with predisposing urological abnormalities. This retrospective study comprised 39 children (22 females and 17 males) who had at least one documented UTI, the presence of an anatomical anomaly of the urinary tract recognized as predisposing to UTI and had undergone ultrasonography of the urinary tract undertaken in fetal life as part of routine maternal ante-natal ultrasonography. Four categories of patients were defined: Group A, those with normal findings on pre-natal ultrasonography and no urological abnormality detected; Group B, those with a urological abnormality detected but where there was a subsequent failure of communication among clinicians; Group C, those with a urological abnormality but who received inappropriate or sub-optimal post-natal management and; Group D, those with a urological abnormality but who had a UTI despite appropriate post-natal management. In each case, the most severe documented episode of UTI was categorized as: Grade I, asymptomatic bacteriuria; Grade II, mild/moderate symptomatic UTI and; Grade III, severe symptomatic UTI necessitating hospital admission. Group A comprised 22 (56%), Group B three (9%), Group C two (5%) and Group D 12 children (31%). Of the 22 children in Group A, nine experienced a UTI of sufficient severity to necessitate hospital admission. Of the 12 children in Group D only one required hospital admission. The failure of pre-natal ultrasonography to identify the underlying predisposing urological abnormality was the most important factor contributing to subsequent UTI in post-natal life. Failure of communication and inappropriate post-natal management were numerically unimportant. In some children, UTI occurred despite pre-natal detection of their underlying anomaly and appropriate post-natal management. However, in this group the UTI was less severe than in those children whose urological anomalies had not been detected by pre-natal ultrasonography.
    British Journal of Urology 07/1996; 77(6):905-8. DOI:10.1046/j.1464-410X.1996.98725.x
  • K Lakhoo, D.F.M. Thomas, A S Najmaldin
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    ABSTRACT: To evaluate the reliability of open inguinal exploration for the investigation of the impalpable testis by reviewing laparoscopic findings after previous negative inguinal exploration. Laparoscopy was performed in 18 boys (with a total of 22 impalpable testes) in whom previous inguinal exploration in their referring hospitals had yielded negative or inconclusive findings. Subsequent management of the impalpable testes was based on laparoscopic findings. Despite previous negative surgical findings at inguinal exploration, laparoscopy revealed that 13 of the 22 impalpable testes (59%) were present, 12 within the abdomen and one in the inguinal canal. Absence of the remaining nine testes was positively confirmed by visualizing confluent blind ending vas and vessels. Inguinal exploration is an unreliable method of investigating the impalpable testis, with an unacceptably high incidence of false-negative or inconclusive findings. Laparoscopy should be undertaken as the initial diagnostic manoeuvre of choice.
    British Journal of Urology 04/1996; 77(3):452-4. DOI:10.1046/j.1464-410X.1996.00824.x

Publication Stats

1k Citations
97.55 Total Impact Points

Institutions

  • 2001–2011
    • Leeds Teaching Hospitals NHS Trust
      • Department of Paediatric Surgery
      Leeds, England, United Kingdom
  • 1990–2010
    • St. James University
      Сент-Джеймс, New York, United States
  • 1989–2001
    • University of Leeds
      • Leeds Institute of Health Sciences (LIHS)
      Leeds, England, United Kingdom
    • Leeds Beckett University
      Leeds, England, United Kingdom
  • 1999
    • Saint James School Of Medicine
      Park Ridge, Illinois, United States