Static spacers play a crucial role in the treatment of complex periprosthetic joint infections of the knee.

PURPOSE: To determine the superior spacer design, a growing number of studies are comparing treatment results between patients having been treated with articulating and static knee spacers in the setting of two-stage revision for periprosthetic joint infection (PJI). In contrast, the primary objective of this study was to compare preoperative characteristics between patients from both spacer groups and examine whether significant differences were present prior to spacer implantation. METHODS: This retrospective, single-centre, cohort study examined the preoperative situation of 80 consecutive knee PJIs between 2017 and 2020. All patients underwent two-stage revision, with 35 (44%) receiving an articulating and 45 (56%) a static spacer. RESULTS: No significant differences were observed in terms of patient gender (p = 0.083), age (p = 0.666), comorbidity (p = 0.1) and preoperative clinical function (p = 0.246). Static spacers were significantly more often used in the presence of a periarticular fistula (p = 0.033), infection of a revision implant (p < 0.001), higher degree of bone loss (p < 0.001) and infection caused by a difficult-to-treat pathogen (p = 0.038). Complication and revision rates were similar for both spacer types during the interim period, while patients with articulating spacers demonstrated a superior clinical function (p < 0.001) during the interim period and after reimplantation. CONCLUSION: Static spacers are being utilised in significantly more complex and unfavourable preoperative scenarios. Therefore, a preoperative selection bias may be at least partially accountable for any disparities observed in postoperative outcomes. To achieve the best possible results, surgeons should know and respect the distinct indications of static and articulating spacers and consequently understand and use them as complementary surgical options. LEVEL OF EVIDENCE: Level III.

Reply to Alt et al. Comment on "Lunz et al. Impact and Modification of the New PJI-TNM Classification for Periprosthetic Joint Infections. J. Clin. Med. 2023, 12, 1262".

We greatly appreciate the comments made by Alt et al. [...].

Impact and Modification of the New PJI-TNM Classification for Periprosthetic Joint Infections.

The comprehensive "PJI-TNM classification" for the description of periprosthetic joint infections (PJI) was introduced in 2020. Its structure is based on the well-known oncological TNM classification to appreciate the complexity, severity, and diversity of PJIs. The main goal of this study is to implement the new PJI-TNM classification into the clinical setting to determine its therapeutic and prognostic value and suggest modifications to further improve the classification for clinical routine use. A retrospective cohort study was conducted at our institution between 2017 and 2020. A total of 80 consecutive patients treated with a two-stage revision for periprosthetic knee joint infection were included. We retrospectively assessed correlations between patients' preoperative PJI-TNM classification and their therapy and outcome and identified several statistically significant correlations for both classifications, the original and our modified version. We have demonstrated that both classifications provide reliable predictions already at the time of diagnosis regarding the invasiveness of surgery (duration of surgery, blood and bone loss during surgery), likelihood of reimplantation, and patient mortality during the first 12 months after diagnosis. Orthopedic surgeons can use the classification system preoperatively as an objective and comprehensive tool for therapeutic decisions and patient information (informed consent). In the future, comparisons between different treatment options for truly similar preoperative baseline situations can be obtained for the first time. Clinicians and researchers should be familiar with the new PJI-TNM classification and start implementing it into their routine practice. Our adjusted and simplified version ("PJI-pTNM") might be a more convenient alternative for the clinical setting.

The first author takes it all? Solutions for crediting authors more visibly, transparently, and free of bias.

With the seventh edition of the publication manual of the American Psychological Association (APA), the APA style now prescribes bias-free language and encourages accessibility even to non-academic audiences. However, even with the newest guidelines, the way we credit authors in psychology remains anachronistic, intransparent, and prone to conflict. It still relies on a sequence-determines-credit approach in the byline, which concurrently is contradicted by the option to consider the last author as the position of the principal investigator depending on the field or journal. Scholars from various disciplines have argued that relying on such norms introduces a considerable amount of error when stakeholders rely on articles for career-relevant decisions. Given the existing recommendations towards a credit-based system, ignoring those issues will further promote bias that could be avoided with rather minor changes to the way we perceive authorship. In this article, we introduce a set of easy-to-implement changes to the manuscript layout that value contribution rather than position. Aimed at fostering transparency, accountability, and equality between authors, establishing those changes would likely benefit all stakeholders in contemporary psychological science.

Experimental Investigation of the Pumping of a Model-Concrete through Pipes.

Many practical aspects of processing fresh concrete depend on its rheology, such as the pumping of the material. It is known that a lubricating layer is formed in the process, which significantly reduces the pumping pressure. However, these phenomena can hardly be considered in the usual rheological measurements. A main problem is the optical inaccessibility of the material, which prevents estimations about, e.g., the thickness of the plug flow or particle migration. In this paper, the pneumatic pumping of a transparent model concrete is performed by means of a test plant. The flow profile over the entire pipe cross-section is resolved in time and space via Particle Image Velocimetry (PIV) measurements. This allows the comparison with the analytical flow profile from rheological measurements of the material using the Buckingham-Reiner equation. A reduction of the pressure loss to around 60% induced through segregation of the material is found. These measurements reflect the rheology of the material under realistic pumping conditions including particle migration. This makes it possible for the first time to observe a transparent material with concrete-like rheology under pulsating pumping conditions and to compare the true and calculated time-resolved pressure loss.

Mid-term absorbable monofilament is safe and effective for gastrointestinal anastomosis - PROMEGAT - A single-arm prospective observational study.

INTRODUCTION: Various suture materials and suture techniques are used to perform gastrointestinal anastomosis after tumour resection, but the best combination is still a matter of debate. METHODS: This multi-centre, international, single-arm, prospective observational study aimed at demonstrating the non-inferiority of a mid-term absorbable monofilament in comparison to braided sutures in gastrointestinal anastomosis. Monosyn suture was used to create the gastrointestinal anastomosis and the frequency of anastomotic leakage until day of discharge was chosen as the primary parameter. The outcome was compared to the results published for braided sutures in the literature. Secondary parameters were the time to perform the anastomosis, length of hospital stay, costs, and postoperative complications. RESULTS: The anastomosis leakage rate was 2.91%, indicating that Monosyn suture was not inferior to braided sutures used in gastrointestinal anastomosis. Of the reported anastomotic suture techniques, the single layer continuous method was the fastest and most economical technique in the present observational study. CONCLUSION: Monosyn suture is safe and effective in gastrointestinal anastomosis and represents a good alternative to other sutures used for gastrointestinal anastomosis. With regard to safety, time and cost-efficiency, the single-layer continuous technique should be considered a preferred method. The transfer of results from clinical studies into daily practice with regard to surgical techniques for gastrointestinal anastomosis should be further evaluated in larger studies or in nationwide registries.

A-Part Gel, an adhesion prophylaxis for abdominal surgery: a randomized controlled phase I-II safety study [NCT00646412].

BACKGROUND: Intra-abdominal surgical intervention can cause the development of intra-peritoneal adhesions. To reduce this problem, different agents have been tested to minimize abdominal adhesions; however, the optimal adhesion prophylaxis has not been found so far. Therefore, the A-Part(®) Gel was developed as a barrier to diminish postsurgical adhesions; the aim of this randomized controlled study was a first evaluation of its safety and efficacy. METHODS: In this prospective, controlled, randomized, patient-blinded, monocenter phase I-II study, 62 patients received either the hydrogel A-Part-Gel(®) as an anti-adhesive barrier or were untreated after primary elective median laparotomy. Primary endpoint was the occurrence of peritonitis and/or wound healing impairment 28 ± 10 days postoperatively. As secondary endpoints anastomotic leakage until 28 days after surgery, adverse events and adhesions were assessed until 3 months postoperatively. RESULTS: A lower rate of wound healing impairment and/or peritonitis was observed in the A-Part Gel(®) group compared to the control group: (6.5 vs. 13.8 %). The difference between the two groups was -7.3%, 90 % confidence interval [-20.1, 5.4 %]. Both treatment groups showed similar frequency of anastomotic leakage but incidence of adverse events and serious adverse events were slightly lower in the A-Part Gel(®) group compared to the control. Adhesion rates were comparable in both groups. CONCLUSION: A-Part Gel(®) is safe as an adhesion prophylaxis after abdominal wall surgery but no reduction of postoperative peritoneal adhesion could be found in comparison to the control group. This may at least in part be due to the small sample size as well as to the incomplete coverage of the incision due to the used application. TRIAL REGISTRATION: NCT00646412.

The TICAP-Study (titanium clips for appendicular stump closure): A prospective multicentre observational study on appendicular stump closure with an innovative titanium clip.

BACKGROUND: To evaluate the effectiveness and safety of the DS Titanium Ligation Clip for appendicular stump closure in laparoscopic appendectomy. METHODS: Overall, 502 patients undergoing laparoscopic appendectomy were recruited for this observational multicentre study in nine study centres between October 2011 and July 2013. The clip was finally applied in 390 patients. Primary outcome variables were feasibility of the clip, intra-abdominal surgical site (abscesses, stump leakages) and superficial wound infections. Patients were followed 30 days after surgery. RESULTS: The clip was applicable in nearly 80 % of patients. Reasons for not applying the clip were mainly an inflamed caecum or a too large diameter of the appendix base. Superficial wound infections were found in nine (2.31 %), intra-abdominal abscesses in five (1.28 %), appendicular stump leak in one (0.26 %), and other adverse events in 22 (5.64 %) patients. In total, 12 (3.08 %) patients were re-admitted to hospital for treatment. Seven re-admissions were surgery-related; ten (2.56 %) patients had to be re-operated. One patient died during the course of the study due to persisting peritonitis (mortality 0.26 %). CONCLUSIONS: The results suggest that the DS Titanium Ligation Clip is a safe and effective option in securing the appendicular stump in laparoscopic appendectomy. The complication rates found with the use of the DS-Clip are comparable to the rates in the literature when other methods are used. TRIAL REGISTRATION: NCT01734837 .

Survival after renal cell carcinoma metastasis to the thyroid: single center experience and systematic review of the literature.

BACKGROUND: Renal cell carcinoma can metastasize to uncommon sites, for example, the thyroid gland where metastases are rarely found. To determine the patient survival and the time between cancer diagnosis and thyroid metastasis, we analyzed a large patient cohort from our hospital records and performed a systematic review. PATIENTS AND METHODS: Patients diagnosed between 1978 and 2007 with thyroid metastases from renal cell carcinoma were retrospectively identified from the hospital database. A systematic literature search was performed for publications describing at least three cases of thyroid metastasis from renal cell carcinoma. Case data from the identified studies were collected and used to determine the survival data. RESULTS: We identified 34 patients (19 females) from our hospital records with a mean age of 67 years (range, 33-79) when thyroid metastasis was diagnosed. Median time to primary metastasis after resection of renal cell carcinoma was 6.5 years (range, 0-25) with a single case of synchronous metastasis. Median survival after primary metastasis was 4.7 years (95% confidence interval [CI]: 1.8-7.6). The systematic review included 32 studies with 285 patients. Case data could be extracted for 202 patients. Median time to thyroid metastasis (without synchronous cases) was 8.8 years (95% CI: 7.5-10.1). Median actuarial survival after thyroid metastasis was 3.4 years (95% CI: 2.2-4.6). Total thyroidectomy was not associated with a better survival compared to partial thyroidectomies. CONCLUSIONS: Time to thyroid metastasis of renal cell carcinoma can be very long, and survival after thyroidectomy is favorable compared to metastasis to other sites.

Mechanical properties and in vivo performance of load-bearing fiber-reinforced composite intramedullary nails with improved torsional strength.

Fiber-reinforced composites (FRC) could be feasible materials for fracture fixation devices if the mechanical properties of the composites are congruent with the local structural properties of bone. In a recently developed FRC implant, bisphenol A dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) resin was reinforced with unidirectional E-glass fibers. The addition of a braided glass fiber sleeving to the unidirectional fibers increased the torsional strength (99.5MPa) of the FRC implants at the expense of the flexural strength (602.0MPa). The flexural modulus was 15.3GPa. Two types of FRC intramedullary nails were prepared; first type was FRC as such, second type was FRC with a surface layer of bioactive glass (BG) granules. Experimental oblong subtrochanteric defect was created in 14 rabbits. The defect, which reduced the torsional strength of the bones by 66%, was fixed with an FRC intramedullary nail of either type. The contralateral intact femur served as the control. This model simulated surgical stabilization of bone metastasis. After 12 weeks of follow-up, the femurs were harvested and analyzed by torsional testing, micro-CT and hard tissue histology. Healed undisplaced peri-implant fractures were noticed in half of the animals irrespective of the type of FRC implant. Torsional testing showed no significant differences between the implantation groups. The torsional strength of the bones stabilized by either type of FRC implant was 83% of that of the contralateral femurs. In histological analysis, no implant debris and no adverse tissue reactions were observed. While the mechanical properties of the modified FRCs were suboptimal, the FRC intramedullary nails supported the femurs without structural failure, even in the cases of peri-implant fractures.

Rationale, bench testing and in vivo evaluation of a novel 5 mm laparoscopic vessel sealing device with homogeneous pressure distribution in long instrument jaws.

BACKGROUND: In 1998, an electrothermal bipolar vessel sealing (EBVS) system was introduced and quickly became an integral component of the surgical armamentarium in various surgical specialties. Currently available EBVS instruments use a scissor-like jaw configuration and closing mechanism, which causes decreasing compression pressure from the proximal to the distal end of the jaws. A new EBVS system is described here which utilizes a different instrument jaw configuration and closing mechanism to enable a more homogeneous pressure distribution despite longer instrument jaws. METHODS: Results of jaw pressure distribution measurements as well as sealing experiments with subsequent burst pressure measurements ex vivo on bovine uterine arteries are demonstrated. Furthermore, an in vivo evaluation of the new EBVS system in a canine and porcine model including histological examination is presented. RESULTS: The device revealed an even pressure distribution throughout the whole jaw length. The ex vivo burst pressure measurements revealed high average burst pressures, above 300 mmHg, independent of the outer diameter (1 to 7 mm) of the tested vessels. Histological evaluation of sealed vessels 21 days postoperatively demonstrated sealed and fused vessels without adjacent tissue damage. CONCLUSIONS: The even pressure distribution leading to a sufficient tissue sealing in combination with the novel closing mechanism and extended jaw length differentiates the novel device from other available EBVS systems. This might offer a reduction of the overall procedure time, which should be further evaluated in a clinical study.

Fibrosis and pancreatic lesions: counterintuitive behavior of the diffusion imaging-derived structural diffusion coefficient d.

INTRODUCTION: Stroma reaction leading to fibrosis is the most characteristic histopathological feature of both pancreatic carcinoma and chronic pancreatitis with increased fibrosis compared with healthy pancreatic tissue and further increased fibrosis during radiochemotherapy. Recent studies using intravoxel incoherent motion-derived parameters did not show differences for structural diffusion constant D between these 2 diseases. The aim of this study was to verify the hypothesis that D correlates with the histopathological grade of fibrosis in pancreatic lesions. MATERIALS AND METHODS: We included 15 patients with histopathologically proven pancreatic carcinoma and 9 patients with histopathologically proven focal chronic pancreatitis. Diffusion-weighted magnetic resonance imaging was performed using 10 b values between 25 and 800 s/mm² before surgery. We calculated the apparent diffusion coefficient and the intravoxel incoherent motion-derived parameters D and f within tumors and focal chronic pancreatitis. The resected tissue was evaluated with regard to the grade of fibrosis. RESULTS: Fourteen patients were found to have moderate fibrosis and 10 patients had severe fibrosis. The difference between the D values for the moderate and severe fibrosis was significant with mean (SD) D value of 1.02 × 10⁻³ (0.48 × 10⁻³ mm/s) and mean (SD) D of 1.22 × 10⁻³ (0.76 × 10⁻³) mm²/s. There were no significant differences for the f and ADC values. CONCLUSIONS: Contrary to our hypothesis, D rises from moderate to severe fibrosis. It seems that cellular complexes surrounded by fibrosis provide more structural limitations than does fibrosis alone. Our data suggest that D is not intuitively related to the degree of fibrosis. Compared with healthy tissue, D is reduced in moderate fibrosis but increases when severe fibrosis is present.

Biological responses of silver-coated thermosets: an in vitro and in vivo study.

Bisphenol A glycidylmethacrylate (BisGMA)/triethyleneglycol dimethacrylate (TEGDMA) thermosets are biomaterials commonly employed for orthopedic and dental applications; for both these fields, bacterial adhesion to the surface of the implant represents a major issue for the outcome of the surgical procedures. In this study, the antimicrobial properties of a nanocomposite coating formed by polysaccharide 1-deoxylactit-1-yl chitosan (Chitlac) and silver nanoparticles (nAg) on methacrylate thermosets were studied. The Chitlac-nAg system showed good anti-bacterial and anti-biofilm activity although its biocidal properties can be moderately, albeit significantly, inhibited by serum proteins. In vitro studies on the silver release kinetic in physiological conditions showed a steady metal release associated with a gradual loss of antimicrobial activity. However, after 3weeks there was still effective protection against bacterial colonization which could be accounted for by the residual silver. This time-span could be considered adequate to confer short-term protection from early peri-implant infections. Preliminary in vivo tests in a mini-pig animal model showed good biological compatibility of Chitlac-nAg-coated materials when implanted in bony tissue. The comparison was made with implants of titanium Ti6Al4V alloy and with a Chitlac-coated thermoset. Bone healing patterns and biocompatibility parameters observed for nAg-treated material were comparable with those observed for control implants.

Renal tumors and second primary pancreatic tumors: a relationship with clinical impact?

BACKGROUND: The occurrence of synchronous or metachronous renal cell carcinoma and pancreatic tumors has been described only in a few cases in the scientific literature. The study of double primary cancers is important because it might provide understanding of a shared genetic basis of different solid tumors and to detect patients at risk for secondary malignancy. METHODS: In a combined analysis of patient registries from University Departments of Urology and Visceral Surgery, 1178 patients with pancreatic tumors and 518 patients with renal cell carcinoma treated between 2001 and 2008 were evaluated, RESULTS: Overall 16 patients with renal cancer and synchronous (n = 6) or metachronous (n = 10) primary pancreatic tumors were detected. The median survival of all patients was 12.6 months, for the patients with synchronous resections 25.7 months and for the patients with metachronous resections 12.2 months, respectively. CONCLUSIONS: The association between these two etiologies of malignancy demands more detailed epidemiological and molecular investigation. Clinical outcomes would support a resection as a recommended clinically valid option.

[Barriers to clinical studies involving medical devices]. / Hürden bei Studien mit Medizinprodukten.

Clinical trials with medical devices need to be considered in terms of the complexity of surgical procedures. Creating the proper environment for the conduct of trials includes improved academic career opportunities in the field of clinical research, methodological competence, and established structures. The challenges and pitfalls in the design of clinical trials involving medical devices are based on aspects such as blinding, placebo, learning curves and surgeons' expertise. Surgical procedures should be standardised, and a study hypothesis needs to be established which is answerable by a relevant and feasible sample size. Besides the above-mentioned challenges, efficient interactions between authorities, universities, hospitals, and medical device manufacturers are mandatory to allow for quality and relevance of clinical studies in this field.

Phase composition and in vitro bioactivity of porous implants made of bioactive glass S53P4.

This work studied the influence of sintering temperature on the phase composition, compression strength and in vitro properties of implants made of bioactive glass S53P4. The implants were sintered within the temperature range 600-1000°C. Over the whole temperature range studied, consolidation took place mainly via viscous flow sintering, even though there was partial surface crystallization. The mechanical strength of the implants was low but increased with the sintering temperature, from 0.7 MPa at 635°C to 10 MPa at 1000°C. Changes in the composition of simulated body fluid (SBF), the immersion solution, were evaluated by pH measurements and ion analysis using inductively coupled plasma optical emission spectrometry. The development of a calcium phosphate layer on the implant surfaces was verified using scanning electron microscopy-electron-dispersive X-ray analysis. When immersed in SBF, a calcium phosphate layer formed on all the samples, but the structure of this layer was affected by the surface crystalline phases. Hydroxyapatite formed more readily on amorphous and partially crystalline implants containing both primary Na(2)O·CaO·2SiO(2) and secondary Na(2)Ca(4)(PO(4))(2)SiO(4) crystals than on implants containing only primary crystals.

Expression of galectin-3 in pancreatic ductal adenocarcinoma.

Galectin-3 influences neoangiogenesis, tumor cell adhesion, and tumor-immune-escape mechanisms. Hence, the expression of galectin-3 in pancreatic ductal adenocarcinoma (PDAC) was evaluated. Galectin-3 expression in PDAC cell lines was proven by the presence of intracellular protein and by release into the supernatant. Furthermore, galectin-3 was found in the majority of human tissue samples. Serum concentrations of galectin-3 in PDAC patients did not differ significantly from healthy donors and did not correlate with established tumor markers. In conclusion, galectin-3 is expressed in PDAC tissues suggesting a role in tumor development; however, no relationship between expression and clinical findings could be established.

Critical appraisal of the International Study Group of Pancreatic Surgery (ISGPS) consensus definition of postoperative hemorrhage after pancreatoduodenectomy.

PURPOSE: Postpancreatectomy hemorrhage (PPH) is one of the most serious complications after pancreatoduodenectomy (PD). This study analyzed and validated the International Study Group of Pancreatic Surgery (ISGPS) definition of PPH and aimed to identify risk factors for early (<24 h) and late PPH. METHODS: Patients who underwent PD for pancreatic head tumors between 2001 and 2008 were included and complications were prospectively recorded. Factors associated with PPH were assessed by uni- and multivariate analysis. RESULTS: Complete datasets were available for 796 patients. Classic and pylorus-preserving PD was performed in 13.8% and 86.2% of the patients, respectively. According to the ISGPS definition, PPH occurred in 29.1% of the cases (232 of 796 patients): 4.8% grade A, 15.2% grade B, and 9.2% grade C. The definition is based largely on surrogate markers (e.g., transfusion requirement) that are affected by other critical illnesses and more than 97% of patients with mild PPH had no clinical signs of bleeding. The need for postoperative intensive care as well as the incidence of pancreatic fistula, relaparotomy, and mortality rates significantly increased from grades A to C. Thirty-seven patients (4.6%) required interventional (endoscopy or angiography) and/or relaparotomy for PPH. Relaparotomy for PPH was performed in 3.1% of all patients. Independent risk factors for early PPH were preoperative anemia (hemoglobin, <11 mg/dl) and multivisceral resection while advanced age, chronic renal insufficiency, increased blood loss, and long operation time were associated with late PPH. CONCLUSIONS: The ISGPS definition of PPH is feasible and applicable but produces a high rate of false positive mild PPH cases. The different grades still significantly correlate with relevant outcome variables, thus the definition discriminates postoperative courses, but a minor modification of the definition of mild PPH is suggested. The new results further demonstrate the need to optimize preoperative anemia and chronic renal insufficiency.

Risk-benefit assessment of closed intra-abdominal drains after pancreatic surgery: a systematic review and meta-analysis assessing the current state of evidence.

BACKGROUND: This systematic review aims to analyse the risk-benefit association of (1) prophylactic drains and/or (2) the time of their removal after pancreatic resection. MATERIALS AND METHODS: A systematic literature search (Medline, Embase, Biosis, and The Cochrane Library) was performed to identify all types of controlled trials comparing the role of drainage or the time of their removal on postoperative complications following pancreatic surgery. Meta-analysis was performed using a random-effects model. RESULTS: Four studies, two randomised trials and two prospective cohort studies, were included in the systematic review and meta-analysis. Removal of drains at day 5 or later did not show an influence on mortality, morbidity, re-intervention or hospital stay compared to no insertion of drains. Early (day 3-4) compared to late (≥ day 5) drain removal significantly reduced pancreatic fistulas (odds ratio (OR) 0.13; 95% confidence interval (CI) 0.03-0.32; P = 0.0002), intra-abdominal collections (OR 0.08; 95% CI 0.01-0.67; P = 0.02) and abscesses (OR 0.26; 95% CI 0.07-1.00; P = 0.05). Moreover, hospital stay was significantly reduced after early drain removal (mean difference -2.60 days; 95% CI -4.74 to -0.46; P = 0.02) CONCLUSION: Further randomised controlled trials are warranted to clarify whether drains are of any use. In case of drain insertion, early removal seems to be superior to late removal.