Laparoendoscopic single-site surgery in urology: where have we been and where are we heading?

One-port, single-incision laparoscopy is part of the natural development of minimally invasive surgery. Refinement and modification of laparoscopic instrumentation has resulted in a substantial increase in the use of laparoendoscopic single-site surgery (LESS) in urology over the past 2 years. Since the initial report of single-port nephrectomy in 2007, urologists have successfully performed various procedures with LESS, including partial nephrectomy, pyeloplasty, orchiectomy, orchiopexy, ureterolithotomy, sacrocolpopexy, renal biopsy, renal cryotherapy, and adrenalectomy. Further advancements in technology, such as magnetic anchoring and guidance systems, and robotic instrumentation, may allow broader application of this emerging surgical technique. Future research is required to determine the intraoperative and postoperative benefits of LESS in comparison with standard laparoscopy.     

Wear in total knee arthroplasty—just a question of polyethylene?: Metal ion release in total knee arthroplasty

Purpose

Biological reactions against wear particles are a common cause for revision in total knee arthroplasty. To date, wear has mainly been attributed to polyethylene. However, the implants have large metallic surfaces that also could potentially lead to metal wear products (metal ions and debris). The aim of this study was to determine the local release of cobalt, chromium, molybdenum and titanium in total knee arthroplasty during a standard knee wear test.

Methods

Four moderately conforming fixed-bearing implants were subjected to physiological loadings and motions for 5×10⁶ walking cycles in a knee wear simulator. Polyethylene wear was determined gravimetrically and the release of metallic wear products was measured using high resolution-inductively coupled plasma-mass spectrometry.

Results

A polyethylene wear rate of 7.28 ± 0.27 mg/10⁶ cycles was determined and the cumulative mass of released metals measured 1.63 ± 0.28 mg for cobalt, 0.47 ± 0.06 mg for chromium, 0.42 ± 0.06 mg for molybdenum and 1.28 ± 0.14 mg for titanium.

Conclusion

For other metallic implants such as metal-on-metal total hip arthroplasty, the metal wear products can interact with the immune system, potentially leading to immunotoxic effects. In this study about 12 % by weight of the wear products were metallic, and these particles and ions may become clinically relevant for patients sensitive to these materials in particular. Non-metallic materials (e.g. ceramics or suitable coatings) may be considered for an alternative treatment for those patients.     

Xenotransplantation: where are we in 2008?

Xenotransplantation holds promise to solve the ever increasing shortage of donor organs for allotransplantation. In the last 2 decades, major progress has been made in understanding the immunobiology of pig-into-(non)human primate transplantation and today we are on the threshold of the first clinical trials. Hyperacute rejection, which is mediated by pre-existing anti-alpha Gal xenoreactive antibodies, can in non-human primates be overcome by complement- and/or antibody-modifying interventions. A major step forward was the development of genetically engineered pigs, either transgenic for human complement regulatory proteins or deficient in the alpha1,3-galactosyltranferase enzyme. However, several other immunologic and nonimmunologic hurdles remain. Acute vascular xenograft rejection is mediated by humoral and cellular mechanisms. Elicited xenoreactive antibodies play a key role. In addition to providing B cell help, xenoreactive T cells may directly contribute to xenograft rejection. Long-term survival of porcine kidney- and heart xenografts in non-human primates has been obtained but required severe T and B cell immunosuppression. Induction of xenotolerance, e.g. through mixed hematopoietic chimerism, may represent the preferred approach, but although proof of principle has been delivered in rodents, induction of pig-to-non-human primate chimerism remains problematic. Finally, it is now clear that innate immune cells, in particular macrophages and natural killer cells, can mediate xenograft destruction, the determinants of which are being elucidated. Chronic xenograft rejection is not well understood, but recent studies indicate that non-immunological problems, such as incompatibilities between human procoagulant and pig anticoagulant components may play an important role. Here, we give a comprehensive overview of the currently known obstacles to xenografting: immune and non-immune problems are discussed, as well as the possible strategies that are under development to overcome these hurdles.     

Joint arthroplasty and infection: where do we stand?

With the field of orthopedic surgery making tremendous advances, no one arena has changed more dramatically then total joint arthroplasty. While this kind of surgery has improved quality of life for many patients, it is not without complications. When they do occur, these complications can be devastating and inflict immense burden on patients and the society. Currently, the rate of periprosthetic joint infection ranges from 0.25% to 2.0%. As the number of total joint arthroplasty procedures is expected to rise considerably, these percentages will impose a financial burden on the field of adult reconstruction. The purpose of our paper is to discuss preventative measures that can be taken to curtail infections, the proper diagnosis of such infections, and the appropriate treatment options.     

Immunosuppression in kidney transplant recipients with COVID-19 infection – where do we stand and where are we heading?

The appropriate immunosuppressive regimen in kidney transplant recipients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2/COVID-19) infection remains unclear. The impact of direct virus injury complicated by dysregulated hyperimmune response with overwhelming release of various cytokines in COVID-19 infected subjects contributes to the complexity of management. The largest concern of the practicing clinicians at current time is how to tailor maintenance immune-modulating therapy during active viral infection and the efficacy of the soon-to-be upcoming immunization for COVID-19. This targeted review aims to cover most of the current evidence on the effect of key maintenance immunosuppressive agents in COVID-19 infection and proposes a line of management to specific scenarios on this very rapidly evolving subject.     

Patient demand matching in total knee arthroplasty: is it necessary?

Patient demand matching has been accepted as an appropriate method of implant management by hospitals for cost reduction. However, there have been no prospective studies to substantiate whether these patients change their demand levels postoperatively. Theoretically, functional activity levels should not increase significantly postoperatively in patients with preoperative low demand levels for patient demand matching to be effective in avoiding premature prosthetic failure. Preoperative and postoperative demand levels were prospectively reviewed in 279 patients undergoing total knee arthroplasty (TKA). Preoperatively, the medium/high-demand patients performed significantly more activities overall than low-demand patients. Postoperatively, both low- and medium/high-demand patients dramatically increased the number of activities performed. The hypothesis that prosthetic choice should be determined by preoperative activity level (demand matching) was not validated by this study because patient activity levels significantly increased in all categories subsequent to TKA.     

Should we use similar perioperative protocols in patients undergoing unilateral and bilateral one-stage total knee arthroplasty?

BACKGROUNDBilateral one-stage total knee arthroplasty (BTKA) is now in greater use as an alternative option for patients with bilateral end-stage knee arthropathy. However, postoperative pain and disablement during convalescence from BTKA, and procedure-related complications have been concerning issues for patients and surgeons. Although some studies reported that BTKA in selected patients is as safe as the staged procedure, well-defined guidelines for patient screening, and perioperative care and monitoring to avoid procedure-related complications are still controversial.AIMTo compare the perioperative outcomes including perioperative blood loss (PBL), cardiac biomarkers, pain intensity, functional recovery, and complications between unilateral total knee arthroplasty (UTKA) and BTKA performed with a similar perioperative protocol. METHODSWe conducted a retrospective study on consecutive patients undergoing UTKA and BTKA that had been performed by a single surgeon with identical perioperative protocols. The exclusion criteria of this study included patients with an American Society of Anesthesiologists score > 3, and known cardiopulmonary comorbidity or high-sensitivity Troponin-T (hs-TnT) > 14 ng/L. Outcome measures included visual analogue scale (VAS) score of postoperative pain, morphine consumption, range of knee motion, straight leg raise (SLR), length of stay (LOS), and serum hemoglobin (Hb) and hs-TnT monitored during hospitalization. RESULTSOf 210 UTKA and 137 BTKA patients, those in the BTKA group were younger and more predominately female. The PBL of the UTKA vs BTKA group was 646.45 ± 272.26 mL vs 1012.40 ± 391.95 mL (P < 0.01), and blood transfusion rates were 10.48% and 40.88% (P < 0.01), respectively. Preoperative Hb and body mass index were predictive factors for blood transfusion in BTKA, whereas preoperative Hb was only a determinant in UTKA patients. The BTKA group had significantly higher VAS scores than the UTKA group at 48, 72, and 96 h after surgery, and also had a significantly lower degree of SLR at 72 h. The BTKA group also had a significantly longer LOS than the UTKA group. Of the patients who had undergone the procedure, 5.71% of the UTKA patients and 12.41% of the BTKA patients (P = 0.04) had hs-TnT > 14 ng/L during the first 72 h postoperatively. However, there was no difference in other outcome measures and complications. CONCLUSIONFollowing similar perioperative management, the blood transfusion rate in BTKA is 4-fold that required in UTKA. Also, BTKA is associated with higher pain intensity at 48 h postoperatively and prolonged LOS when compared to the UTKA. Hence, BTKA patients may require more extensive perioperative management for blood loss and pain, even if having no higher risk of complications than UTKA.