Browsing by Author "Lazarus, John"
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- ItemOpen AccessA 15-year retrospective review of urodynamic studies in Children at Red Cross War Memorial Childrens Hospital (RCWMCH), Cape Town, South Africa(2022) Mosalakatane, Thembisile Dintle; Coetzee, Ashton; Wright, Anne; Raad, Jeanette; Lazarus, John; Nourse, Peter; Howlett, Justin; McCulloch, MignonBackground: Despite the undeniable diagnostic benefits of urodynamic studies (UDS), their adoption into clinical practice in Africa has been slow. This study aimed to review the use of invasive UDS in children at a tertiary paediatric hospital in South Africa. Methods: A retrospective analysis of 1108 UDS was conducted. Patient demographic characteristics, primary diagnosis, indication and urodynamic outcomes were reviewed. Presence of urodynamic high-risk features were documented, and a comparison was made between the first study and follow-up study. Results: This study revealed increasing trends in the use of UDS from 2015. Referrals were from Urology (37.7%), Spinal defects clinic (34.4%), Nephrology (20.8%) and other departments (7.0%). The most common reason for referral was review of medical treatment (36.5%). Spinal dysraphism (58.3%) accounted for the majority of conditions seen. Majority (59.1%) of the patients were receiving more than one type of bladder treatment at the time of their first study, with clean intermittent catheterisation (46.5%) being the most common form of bladder management. 97.5% of studies were performed using transurethral bladder catheterization. Urodynamic diagnosis was neurogenic in 74.0%, anatomical (12.2%), functional (8.8%) and normal (5.0%). There was statistically significant improvement in bladder compliance, detrusor leak point pressure and detrusor sphincter dyssynergia between the first study and a subsequent study following therapeutic intervention. Conclusion: The unique ability of UDS to demonstrate changes in detrusor pressures, which is a common reason for therapy failure, makes UDS an invaluable tool in the diagnosis and management of children with lower urinary tract dysfunction.
- ItemOpen AccessAn analytical and experimental investigation of the hydraulic transport of high concentration mixed regime slurries(1988) Sive, Anthony Wyndham; Lazarus, JohnMixed regime slurries are those slurries comprised of broad particle size distributions. Slurries of this type with volume concentration up to 50 (relative density of approximately 1.8) are considered.. An analytical model has been developed for such slurries. The inputs to the model are mean mixture flow rate, delivered. concentration and the particle and pipeline characteristics.. In order to calculate in situ concentration, the concentration distribution is found by using a diffusion model. A logarithmic velocity distribution is also required and is used to ascribe velocity values to volume elements in a concentric computational grid. Calculated values of mean mixture flow rate and delivered concentration are compared to the input values and an iterative procedure is employed to ensure equality with a result being the computation of in situ concentration. The model is applicable over the complete range of flow regimes including stationary bed, sliding bed and suspended flow. The particular regime prevalent for the input values will be ascertained by the model aid the energy gradient calculated. The model is compared to 3 existing correlations in the literature, for mixed regime flow, using 1345 data points collected at the University of Cape Town test facility and 1630 data points from other institutions. The test facility used comprises two systems each with two pipelines and separate centrifugal pumps. The four pipelines range from 50mm inside diameter to 140mm inside diameter. A data acquisition system continuously monitors pressures, velocity and temperature. Mixture concentration and velocity are checked using a weigh tank which is filled over a time interval by diverting the slurry flow. Pressures are checked with water manometers. The data acquisition system is interfaced to a microcomputer that calculates required. values and outputs tables and graphs of measured values. Detailed observations of the flow conditions are made through clear viewing sections in each pipeline. A qualitative investigation of periodic flow phenomena observed is presented. These are a result of sliding bed flow and include dunes, waves and slugs. A two-fluid model is proposed and the mechanisms whereby these structures form, grow and eventually disperse is discussed.
- ItemOpen AccessComparative Analysis of Kidney Stone Composition in Patients from Ghana and South Africa: Case Study of Kidney Stones from Accra and Cape Town(2019) Akpakli, Evans Ametefe; Kaestner, Lisa-Ann; Lazarus, JohnAim: The primary aim of this study was to describe and compare the kidney stone composition of kidney stone patients receiving treatment at the Korle-Bu Teaching Hospital (KBTH), Accra (Ghana) and Groote Schuur Hospital (GSH), Cape Town (South Africa). Methods: The study was a retrospective folder review of patients treated for kidney stone disease at the Korle-Bu Teaching Hospital in Accra (Ghana) and Groote Schuur Hospital in Cape Town (South Africa). Patients who were treated for kidney stone disease between 1st June 2016 and 31st May 2018 were recruited and their folder numbers were retrieved from theatre log books. A total of hundred and sixty-three (n=163) folders (n=30 KBTH; n=133 GSH) were subsequently retrieved from the records department of the two facilities. Demographic data and kidney stone analysis results were extracted and analyzed using the R statistical software. Results: The age of participants at the KBTH ranged from 24 to 75 years with a median age of 45 years, while the ages of participants at the GSH ranged between 19 to 77 years with a median age of 48 years. Males were the majority stone formers for both hospitals [56.7% KBTH; 59.4% GSH]. However, there was no significant statistical difference in gender (p=0.9447) and age (p=0.2612) between the two groups. Calcium oxalate (86.7%) and uric acid (90.0%) were the commonest components of the kidney stones analyzed from the KBTH. Calcium oxalate (66.2%) and carbonate apatite (40.6%) emerged as the most common components of the stones analyzed from the GSH. Brushite (3.0%), cystine (3.8%) and struvite (19.6%) stones were only found in the stones of participants receiving treatment at the GSH. All kidney stones from the KBTH were mixed; made up of at least two chemical components. Pure kidney stones were only found among the GSH dataset constituting 48.9% of all the stones analyzed. While all KBTH stones were mixed stones, female patients from GSH formed more mixed stones than their male counterparts (M:F = 40.5%:66.67%). Infection kidney stones (struvite and carbonate apatite) were also predominantly found among female stone formers in this study. Conclusion: The findings indicate that the participants from the two facilities are not different in terms of gender and age. However, the composition of stones was found to be different between participants from both hospitals. This suggests that that kidney stone composition may be influenced by patients’ geographical location and/or cultural background. Further studies with prospective or longitudinal data and larger samples are needed to provide more insight into the composition of kidney stones of African patients.
- ItemOpen AccessDesign of a wireless ureteropyeloscope(2015) Ncube, Mkhokheli; Sivarasu, Sudesh; Lazarus, JohnUreteroscopy is a form of endoscopy that concerns itself with the urinary system. Flexible ureteropyeloscopes are instruments used to access the urinary system for diagnostic and therapeutic procedures. An average ureteropyeloscope requires a repair for every 3 to 13 hours of use, or alternatively 6 to 15 procedures. Therefore, there is a need to increase the durability of the ureteropyeloscope to lower the frequency of repairs required. In addition, the number of cables in the workspace needs to be reduced for improved handling by the clinician. The present study details the design of an ureteropyeloscope, which is modelled after currently existing instruments. Current endoscopes use fibre-optics for lighting area of interest as well as image acquisition. However, the ureteropyeloscope discussed was developed with a camera at the distal end of the insertion tube as its image acquisition system. The images captured were transmitted to a monitor for viewing via a wireless transmission module. The ureteropyeloscope discussed in the study was aimed at increasing the durability of the deflection unit of the ureteropyeloscope, with primary component made of nitinol, and reducing the number of cables around the workstation by using wireless means to transmit images from image acquisition system to monitor.
- ItemOpen AccessEvaluating the role of a 99mTc-HYNIC-PSMA SPECT scan following a negative bone scan in men with prostate cancer: a single-centre, retrospective cohort study(2023) Oppel, Cleve; Lazarus, JohnPurpose: This study aimed to review the management of patients with high-risk and unfavourable intermediate-risk prostate cancer, who had a 99mTc-HYNIC-PSMA SPECT (technetium-99m hydrazine nicotinamide prostate-specific membrane antigen singlephoton emission computerised tomography) scan following a negative 99mTc-MDP (technetium-99m methylene diphosphonate) bone scan. Materials and methods: This study is a retrospective review of patients with high-risk and unfavourable intermediate-risk prostate cancer, who underwent a 99mTc-PSMA SPECT scan after a negative/equivocal bone scan between January 2018 and December 2020. Patients with a life expectancy of less than 10 years were excluded. Results: A total of 64 patients were investigated. The mean age was 63 years and the mean prostate-specific antigen (PSA) level was 40 ng/mL. The International Society of Urological Pathology (ISUP) scores were as follows: ISUP 1 in six patients, ISUP 2 in eight patients, ISUP 3 in 13 patients, and ISUP > 4 in 37 patients. A positive 99mTc-PSMA SPECT scan for disease metastases occurred in 20% of the patients who had a negative bone scan. Seven of the patients with a positive 99mTc-PSMA SPECT scan received a bilateral orchiectomy, while four patients received treatment with radical intent. Management of patients with both scans negative included external beam radiotherapy (EBRT) and androgen deprivation therapy (ADT) (n = 47), and radical prostatectomy with or without lymph node (LN) dissection (n = 4). A limiting factor was that not every patient underwent conventional cross-sectional imaging of the pelvis and prostate prior to intervention. Conclusion: A 99mTc-PSMA SPECT scan is a valuable diagnostic tool and was able to identify one in five men (20%) who are understaged by bone scan, allowing for their management plan to be tailored and sparing them morbid intervention.
- ItemOpen AccessGenetic basis of human disorders of gonadal development(2018) Maison, Patrick Opoku Manu; Lazarus, JohnSouth Africa is unique in the arena of Intersex, in that for unknown reasons we have a very high percentage of ovotesticular DSD (True Hermaphrodite). Whereas ovotesticular DSD is the least common cause of hermaphroditism in other parts of the world, it is the most common cause of hermaphroditism in South Africa. There have been several studies in the past to determine the cause of ovotesticular DSD in our population but none of these studies found appropriate answers. The current state of understanding implicates signaling and signal transduction molecules and transcription factors suggesting that it is likely not all of the genetic factors involved have already been identified. It was hypothesized that exome sequencing of individuals with DGDs will identify new mutations and genes for these conditions. Therefore, this study aims to identify additional genes that are associated with ovotesticular DSD. By using a whole-genome sequencing approach we expected to be able to identify rare variants with this condition and determine the prevalence of mutations in these genes in the ovotesticular DSD population. After obtaining informed consent, blood specimen was obtained from eleven out of fifteen patients who had histological diagnosis of Ovotesticular DSD at the Red Cross War Memorial Hospital over a 10 year period. Blood specimen was also obtained from the biological parents of these children and sent to the Ostrer laboratory for whole genome sequencing and analysis. At the Ostrer laboratory, high quality DNA was extracted from blood for all of subjects and lymphoblastoid cell lines were created. Following sample preparation using the Illumina library preparation kit, sequencing was accomplished using paired-end sequencing technology on an Illumina HiSeq2000 sequencer. The data from the Illumina sequencers was analyzed first using the Illumina sequencing data analysis pipeline for quality control. Paired end reads were aligned to the Human Reference Genome (NCBI Build 36) using the BWA software. Each alignment was assigned a mapping quality score by BWA, which is the Phredscaled probability that a read is misaligned. The basic functional annotation of SNPs/Indels is performed by ANNOVAR. The clinical features of these patients was consistent with those found by other studies on Ovotesticular DSD in South Africa and it also showed the same pattern of variation to the clinical features of Ovotesticular DSD from other parts of the world. Similar to previous South African studies, this study found no convincing gene mutations as the possible etiology of Ovotesticular DSD in South Africa. Whiles gene mutations such as duplication of SOX 9 have been found in patients with XX Ovotesticular DSD from outside South Africa, this study could not identify any such mutations. This further adds to the suspicion that the unique features of Ovotesticular DSD in South Africa suggests a different etiology from that of other parts of the world. In conclusion, the etiology of Ovotesticular DSD in South Africa still remains elusive. It is however possible that a genetic mutation may be found from a more critical analysis of the genome of the patients and their parents.
- ItemOpen AccessInvestigating racial differences in clinical and pathological features of prostate cancer in South African men(2016) Dewar, Malcolm James; Kaestner, Lisa-Ann; Lazarus, JohnThe aim of this project is to study the clinical and pathological features of prostate cancer in men from different racial groups in the Western Cape in an attempt to define the characteristics of the disease locally. Specifically we wanted to compare black with coloured and white patients.
- ItemOpen AccessNear-fatal TURP syndrome associated with similarities in irrigant fluid packaging appearance(2008) Lazarus, John; Batty, Dee; Moolman, ConrayWe describe a case of severe iatrogenic transurethal resection of the prostate (TURP) syndrome associated with confusing irrigant fluid packaging. TURP syndrome is described, as well as steps taken to request industry to alter the packaging.
- ItemOpen AccessRenal Cortical Transit time as a predictor for pyeloplasty in paediatric patients with unilateral hydronephrosis at the Red Cross War Memorial Children's Hospital(2018) More, Stuart Setjhaba; Brink, Anita; Mann, Michael D.; Lazarus, JohnBackground: Majority of patients with unilateral hydronephrosis (HN) detected on ultrasound (US) do not require pyeloplasty. Indications for pyeloplasty are in patients with symptomatic obstruction (recurrent flank pain), complications such as urinary tract infection, a drop in differential renal function (DRF) of more than 10% and a progressive increase in the anterior posterior diameter (APD) in subsequent studies. Schlotmann et al, Piepsz et al and Harper et al have demonstrated the measurement of the cortical transit time (CTT) to predict the need for patient who may require pyeloplasty. Objectives: To assess if the CTT would have predicted a drop in DRF in patients with unilateral HN on the affected side. In addition to assess whether the CTT would differ on the first renogram between those patients who had a pyeloplasty and those who did not have a pyeloplasty at the Red Cross War Memorial Children’s Hospital (RCWMCH). Methods: Sixty eight (68) patients with at least two renograms with unilateral HN with a normal contralateral kidney were observed retrospectively between December 2000 and May 2015. The CTT was recorded for the upper, middle and lower third of each kidney and the mean used as the CTT of the kidney. Each renogram was processed three times to measure the DRF using the Rutland Patlak and Integral methods. The mean of the three DRF measurements was used for analysis. Results: The mean CTT of the left and right hydronephrotic kidneys were 6.0minutes and 6.7minutes respectively. A significant relationship was demonstrated in the CTT and DRF as well as CTT and APD in the first renogram of those patients who did not have a pyeloplasty (p < 0.05). There was no difference between the DRF of the first and second renograms in those patients who did not have a pyeloplasty. In the 20 patients who had a pyeloplasty, there was a drop of more than 10% in the DRF of 3 patients. No difference was seen in the DRF or in the CTT between the first and second renogram. The CTT was shorter in the second renogram in 9 of the 20 patients who had a pyeloplasty. No significant difference was found in the CTT or DRF when comparing the group who had surgery against the group who did not have surgery. Conclusion: The current study was unable to demonstrate in our series of patients that CTT can predict those patients who would require pyeloplasty. This may be owing to the retrospective nature of the study and the reliance on the clinical notes for the US data and surgical notes. In future, a prospective study evaluating the relationship between CTT and a drop in the DRF should be undertaken in this unit.
- ItemOpen AccessRetrospective outcome analysis of urethroplasties performed for various etiologies in a single South African centre(Elsevier Ltd., 2012) Van Den Heever, A P; Lazarus, John; Naude, J H; Wiechers, L; Tsheisi, MObjectives: To compare the results of anastomotic versus augmentation urethroplasty (buccal mucosa graft (BMG) onlay), as well as dorsal versus ventral BMG techniques. Methods: A retrospective audit of 69 patients who underwent urethroplasty at Eersteriver Hospital in Cape Town, South Africa between October 2004 and July 2011 was undertaken. Analysis included stricture etiology, location and length, type of surgery performed as well as complication rates over the follow-up period. Results: The predominant stricture etiologies were traumatic and infective causes (55%), with a mean stricture length of 3 cm (0.5–15 cm). Forty two patients had bulbar urethra strictures (61%), with 8 (11%) located in the posterior, and penile & bulbar regions, respectively. The remaining strictures were located in the penile urethra (16%). Surgery performed included bulbar (12) and membranous anastomotic (8) urethroplasty, ventral (13) and dorsal (22) buccal mucosa onlay grafts (BMG), and 2-stage urethroplasty (14). Overall stricture recurrence was seen in 9 patients (13%), including 1 patient (8%) of the anterior end-to-end anastomotic group compared to 2 patients (6%) of the onlay BMG group (p = 0.77). The re-stricture rates were 5% and 8% in the dorsal (1/22) and ventral BMG onlay groups (1/13), respectively (p = 0.72).
- ItemOpen AccessSingle sitting endourological management of retained ureteral stents at Groote Schuur Hospital: A 3-year retrospective study(2023) Ombuki, Winstar; Lazarus, JohnDouble J stents have become essential components in endourological and open urological procedures. The removal ofseverely encrusted and retained ureteralstents poses a management challenge for urologists as multiple procedures are often required to remove them. Objectives: Main Objective: To determine the proportion of patients with retained stents who can be rendered stent free with single-sitting endourological management Secondary Objectives: To describe the number of procedures required to render patients with retained stents stent and stone free. To describe the demography and clinical variables of patients with retained ureteral stents at Groote Schuur Hospital Materials and Objectives: A retrospective study was conducted between 1st February 2018 and 31st January 2022. All 30 patients that met inclusion criteria with retained and encrusted patients were reviewed. All patients were initially evaluated with radiographic imaging for assessment of stone burden. Treatment decisions were based on the FECAL classification of retained stents. Multimodal endourological procedures were used to achieve the stents and render the patient stone free. Results: The average age of the participants was 39.4 years while the male participants were the most common, 66% (n= 19). A total of 47 Urological procedures were performed to render all 30 patients' stent and stone free. The average duration of indwelling time was 20.35 months and a range of 66 months with a minimum of 4 months and a maximum of 70 months. The main indication for stent placement was stone obstruction ( 55.56%) 41% (n= 12) of patients had PCNL while 48% (n= 14) patients received ureteroscopy and laser lithotripsy. The most common FECAL classification was IV at 59% (n= 17). The most common side affected by stent encrustation was the right (55.56%). Conclusion: The endoscopic combined approached is safe and feasible technique that allows removal of retained and encrusted stents in a single procedure.
- ItemOpen AccessStentless pyeloplasty for paediatric uretero-pelvic junction obstruction: a 15- year experience(2024) Mbwambo, Orgeness Jasper; Lazarus, JohnIntroduction Stenting after pyeloplasty is a traditional operative practice with the aim of ensuring a patent anastomosis and preventing complications such as urinary leakage, dehiscence and reducing risk of stricture formation. However, it has the disadvantage of complications such as infection, encrustation, migration, breakage, and increased cost of surgery to remove the stent. Therefore, recently stentless pyeloplasty has been advocated as a feasible alternative. This study aimed to evaluate the outcome of stentless dismembered pyeloplasty for congenital ureteroplevic junction obstruction. Methods We retrospectively reviewed the data of paediatric patients who underwent dismembered pyeloplasty due to congenital ureteropelvic junction obstruction (UPJO) between January 2008 and July 2022. Patients' demographics, indications for surgery, follow up data and complications were recorded on data extraction sheet. The success rate was defined as lack of need for intervention or reoperation postoperatively. This
- ItemOpen AccessTransitional and turbulent flow of non-Newtonian slurries in pipes(1995) Slatter, Paul Thomas; Lazarus, John; Cooke, RobertThe only reliable approach open to designers of pipeline systems conveying non-Newtonian slurries in the turbulent flow regime has been large scale-pipe-tests. This thesis addresses this design problem, with particular emphasis on the theoretical modelling of the laminar/turbulent transition and turbulent flow behaviour of these slurries in pipes. The literature and theory pertinent to-the flow of slurries in pipes-is examined. The development of non-Newtonian Reynolds numbers and laminar/turbulent transition criteria are presented and existing theoretical models for predicting turbulent flow are reviewed. Three test facilities were built for the establishment of a data base of non-Newtonian slurry behaviour - a tube viscometer and two pumped recirculating pipe test rigs.