André van der Merwe

Patient‐specific intervertebral disc implants using rapid manufacturing technology

Purpose – The purpose of this paper is to develop a process chain for design and manufacture of endplates of intervertebral disc implants, with specific emphasis on designing footprint profiles and matching endplate geometry.Design/methodology/approach – Existing techniques for acquiring patient‐specific information from CT scan data was and a user‐friendly software solution was developed to facilitate pre‐surgical planning and semi‐automated design. The steps in the process chain were validated experimentally by manufacturing Ti6Al4 V endplates by means of Direct Metal Laser Sintering to match vertebrae of a cadaver and were tested for accuracy of the implant‐to‐bone fitment.Findings – Intervertebral disc endplates were successfully designed and rapid manufactured using a biocompatible material. Accuracy within 0.37 mm was achieved. User‐friendly, semi‐automated design software offers an opportunity for surgeons to become more easily involved in the design process and speeds up the process to more accura...

Androgen Metabolism Gene Polymorphisms, Associations with Prostate Cancer Risk and Pathological Characteristics: A Comparative Analysis between South African and Senegalese Men

Prostate cancer is the most common cancer in men in developed countries and the leading cause of mortality in males in less developed countries. African ethnicity is one of the major risk factors for developing prostate cancer. Pathways involved in androgen metabolism have been implicated in the etiology of the disease. Analyses of clinical data and CYP3A4, CYP3A5, and SRD5A2 genotypes were performed in South African White (120 cases; 134 controls), Mixed Ancestry (207 cases; 167 controls), and Black (25 cases; 20 controls) men, as well as in Senegalese men (86 cases; 300 controls). Senegalese men were diagnosed earlier with prostate cancer and had higher median PSA levels compared to South African men. Metastasis occurred more frequently in Senegalese men. Gene polymorphism frequencies differed significantly between South African and Senegalese men. The CYP3A4 rs2740574 polymorphism was associated with prostate cancer risk and tumor aggressiveness in South African men, after correction for population stratification, and the SRD5A2 rs523349 CG genotype was inversely associated with high-stage disease in Senegalese men. These data suggest that variants previously associated with prostate cancer in other populations may also affect prostate cancer risk in African men.

Penile allotransplantation for penis amputation following ritual circumcision: a case report with 24 months of follow-up

INTRODUCTION Ritual circumcision complicated by gangrene is a leading cause of penile loss in young men in South Africa. This deeply rooted cultural tradition is unlikely to be abolished. Conventional reconstructive techniques using free vascularised tissue flaps with penile implants are undesirable in this often socioeconomically challenged group because donor site morbidity can hinder manual labour and vigorous sexual activity might lead to penile implant extrusion. The psychosociological effects of penile loss in a young man are devastating and replacing it with the same organ is likely to produce the maximum benefit. METHODS We first performed a cadaver-to-cadaver penile transplantation as preparation. After approval from the Human Research Ethics Committee was obtained, we recruited potential recipients. We screened the potential participants for both physical and psychological characteristics, including penile stump length, and emotional suitability for the procedure. A suitable donor became available and the penis was harvested. We surgically prepared the penile stump of the recipient and attached the penile graft. Immunosuppression treatment with antithymyocyte globulin, methylprednisolone, tacrolimus, mycophenolate mofetil, and prednisone were commenced. Tadalafil at 5 mg once per day was commenced after 1 week as penile rehabilitation and was continued for 3 months. We collected on quality-of-life scores (Short Form 36 version 2 [SF-36v2] questionnaires) before surgery and during follow-up and measured erectile function (International Index for Erectile Function [IIEF] score) and urine flow rates at 24 months post transplant. FINDINGS The warm ischaemia time for the graft after removal was 4 min and the cold ischaemia time was 16 h. The surgery lasted 9 h. An arterial thrombus required urgent revision 8 h after the operation. On post operative day 6, an infected haematoma and an area of proximal skin necrosis were surgically treated. The recipient was discharged after 1 month and first reported satisfactory sexual intercourse 1 week later (despite advice to the contrary). The recipient reported regular sexual intercourse from 3 months after the operation. An episode of acute kidney injury at 7 months was reversed by reducing the tacrolimus dose to 14 mg twice per day. At 8 months after surgery, the patient had a skin infection with phaeohyphomycosis due to Alternaria alternata, which we treated with topical antifungal medication. Quality-of-life scores improved substantially after the operation (SF-36v2 mental health scores improved from 25 preoperatively, to 57 at 6 months and 46 at 24 months post transplant; physical health scores improved from 37 at baseline to 60 at 6 months and 59 at 24 months post-transplant). At 24 months, measured maximum urine flow rate (16·3 mL/s from a volume voided of 109 mL) and IIEF score (overall satisfaction score of 8 from a maximum of 10) were normal, showing normal voiding and erectile function, respectively. INTERPRETATION Penile transplantation restored normal physiological functions in this transplant recipient without major complications in the first 24 months. FUNDING Department of Health, Western Cape Government.

Lessons learned from the world’s first successful penis allotransplantation

We performed a successful penis allotransplantation on 11 December 2014. Sharing the lessons learned might help more patients in need to be treated this way. We divided the project into manageable segments that was each overseen by an expert. The ethical review and conduct paved the way for a publically acceptable and successful project. Screening for a psychological stable recipient is important. The most difficult part of the project was finding a donor penis. This was successfully negotiated with the family of a brain dead donor by creating a neo-phallus for the donor, thereby maintaining the dignity of the donor. Working with transplant coordinators that are sympathetic to aphallic men is crucial. Surgeons versed in microvascular techniques is a critical part of the team. Transplant immunologists have to adapt to treat composite tissue transplantation patients.Graphical Abstract

Analysis of Prostate Cancer Susceptibility Variants in South African Men: Replicating Associations on Chromosomes 8q24 and 10q11

Genome-wide association studies (GWAS) have implicated single nucleotide polymorphisms (SNPs) on chromosomes 2p15, 6q25, 7p15.2, 7q21, 8q24, 10q11, 10q26, 11q13, 17q12, 17q24, 19q13, and Xp11, with prostate cancer (PCa) susceptibility and/or tumour aggressiveness, in populations of African, European, and Asian ancestry. The objective of this study was to confirm these associations in South African Mixed Ancestry and White men. We evaluated 17 prioritised GWAS SNPs in South African cases (331 Mixed Ancestry and 155 White) and controls (178 Mixed Ancestry and 145 White). The replicated SNP associations for the different South African ethnic groups were rs7008482 (8q24) (p = 2.45 × 10−5), rs6983267 (8q24) (p = 4.48 × 10−7), and rs10993994 (10q11) (p = 1.40 × 10−3) in Mixed Ancestry men and rs10993994 (p = 1.56 × 10−9) in White men. No significant associations were observed for the analyses stratified by disease aggressiveness in the individual and the combined population group analysis. The present study demonstrates that a number of known PCa susceptibility variants may contribute to disease susceptibility in South African men. Larger genetic investigations extended to other South African population groups are warranted to confirm the role of these and other SNPs in disease susceptibility.

Urological aspects of HIV and AIDS

The use of highly active antiretroviral therapy (HAART) in HIV-infected people has led to a dramatic decrease in the incidence of opportunistic infections and virus-related malignancies such as non-Hodgkin lymphoma and Kaposi sarcoma, but not cervical or anal cancer. Advanced-stage cervical cancer is associated with a high incidence of urological complications such as hydronephrosis, renal failure, and vesicovaginal fistula. Adult male circumcison can significantly reduce the risk of male HIV acquisition. Although HAART does not completely eradicate HIV, compliance with medication increases life expectancy. HIV infection or treatment can result in renal failure, which can be managed with dialysis and transplantation (as for HIV-negative patients). Although treatment for erectile dysfunction—including phosphodiesterase 5 inhibitors, intracavernosal injection therapy, and penile prosthesis—can increase the risk of HIV transmission, treatment decisions for men with erectile dysfunction should not be determined by HIV status. The challenges faced when administering chemotherapy to HIV-infected patients with cancer include late presentation, immunodeficiency, drug interactions, and adverse effects associated with compounded medications. Nonetheless, HIV-infected patients should receive the same cancer treatment as HIV-negative patients. The urologist is increasingly likely to encounter HIV-positive patients who present with the same urological problems as the general population, because HAART confers a prolonged life expectancy. Performing surgery in an HIV-infected individual raises safety issues for both the patient (if severely immunocompromised) and the surgeon, but the risk of HIV transmission from patients on fully suppressive HAART is small.

3D Printing Dimensional Calibration Shape: Clebsch Cubic

3D printing and other layer manufacturing processes are challenged by dimensional accuracy. Various techniques are used to validate and calibrate dimensional accuracy through the complete building envelope. The validation process involves the growing and measuring of a shape with known parameters. The measured result is compared with the intended digital model. Processes with the risk of deformation after time or post-processing may find this technique beneficial. We propose to use objects from algebraic geometry as test shapes. A cubic surface is given as the zero set of a degree 3 polynomial in 3 variables. A class of cubics in real 3D space contains exactly 27 real lines. These lines can be used for dimensional calibration. Due to the thin shape geometry the material required to produce an algebraic surface is minimal. We provide a library for the computer algebra system Singular which, from 6 given points in the plane, constructs a cubic and the lines on it.

DIGITALISATION OF SHOP-FLOOR OPERATIONS IN THE SOUTH AFRICAN TOOL, DIE, AND MOULD-MAKING INDUSTRY

Digitalisation has been advocated as a possible strategy to improve the competitiveness of tool, die, and mould-making (TDM) companies in the 21st century. The recent rise of digital technologies, such as Internet of Things devices, now makes digitalisation an achievable reality. This paper focuses on the digitalisation of shop-floor operations in the South African TDM industry through the development of a novel mobile data collection (MDC) tool known as a shop-floor management system (SMS). The developed SMS was deployed to, and validated in, a selected tooling company for various products. The developed system improved the shop-floor’s real-time data collection.

Bladder Cancer: A Perspective for Tropical Regions

Bladder cancers in the tropical areas are often not common, with clear exceptions such as in Egypt. However, if diagnosed, it is often in an advanced stage needing radical curative treatment if available. Internal diversions have its problems as stated above, but neobladder, if possible, is generally a reasonable alternative to external stoma appliances. As life expectancy in the tropics is increasing, the incidence of bladder cancer in the tropical areas will also increase.

Retroperitoneal Laparoendoscopic Single-Site Donor Nephrectomy

Abstract Introduction: Donor nephrectomy with laparoendoscopic single-site (LESS) surgery has been reported via the transperitoneal approach. The umbilicus (e-NOTES [embryological Natural Orifice Translumenal Endoscopic Surgery]) is a popular site, but leaves a nasty scar, and extraction of the kidney may be complex, risking warm ischemic renal injury. Our units have a combined experience of around 300 retroperitoneal donor nephrectomies and therefore want to offer single-site surgery to our patients. Materials and Methods (including a description of the video): We operated on two men on the right side (body mass index 32 and 33 kg/m2). We made a single 6-cm surgical incision in the right groin, below the abdominal skin crease, and developed the retroperitoneum under direct vision before using an inflation balloon behind the kidney. Using Gelport™ and bariatric/curved laparoscopic instruments, gas pressure was maintained and Gerotas fascia opened. Normal triangulation is maintained as the edges of the Ge...