Laparoscopic sleeve gastrectomy vs one-anastomosis gastric bypass 5-year follow-up: a single-blinded randomized controlled trial.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is the most performed bariatric procedure worldwide, whereas one-anastomosis gastric bypass (OAGB) is the third most performed procedure. Both procedures have reported good weight loss (WL) and low complications. However, should both have differences in the durability of WL and malnutrition? METHODS: A single-blinded, randomized controlled trial of 300 patients was conducted to compare the outcomes of LSG and OAGB over a 5-year follow-up. The primary endpoint was WL in percentages of total WL (%TWL) and excess WL (%EWL). The secondary endpoints were complications, gastroesophageal reflux disease (GERD), associated medical problems, bariatric analysis and reporting outcome system (BAROS) assessment, and weight recurrence (WR). RESULTS: Overall, 201 patients (96 in the LSG group and 105 in the OAGB group) completed 5 years of follow-up. OAGB had significantly higher %TWL and %EWL than those of LSG throughout the follow-up. LSG had significantly higher WR and GERD. Both procedures had significant improvement in associated medical problems and BAROS scores compared with baseline, with no significant difference. WR was associated with higher relapse of associated medical conditions after initial remission and with lower BAROS scores regarding WL scores. CONCLUSION: OAGB had significantly higher WL, less WR, and less GERD. However, it had a higher incidence of bile reflux. Both procedures had comparable complication rates, excellent remissions in associated medical problems, and improved quality of life. WR was associated with significantly more relapse of associated medical problems and significantly lower BAROS scores.

Dynamics of invariant solutions of the DNA model using Lie symmetry approach.

The utilization of the Lie group method serves to encapsulate a diverse array of wave structures. This method, established as a robust and reliable mathematical technique, is instrumental in deriving precise solutions for nonlinear partial differential equations (NPDEs) across a spectrum of domains. Its applications span various scientific disciplines, including mathematical physics, nonlinear dynamics, oceanography, engineering sciences, and several others. This research focuses specifically on the crucial molecule DNA and its interaction with an external microwave field. The Lie group method is employed to establish a five-dimensional symmetry algebra as the foundational element. Subsequently, similarity reductions are led by a system of one-dimensional subalgebras. Several invariant solutions as well as a spectrum of wave solutions is obtained by solving the resulting reduced ordinary differential equations (ODEs). These solutions govern the longitudinal displacement in DNA, shedding light on the characteristics of DNA as a significant real-world challenge. The interactions of DNA with an external microwave field manifest in various forms, including rational, exponential, trigonometric, hyperbolic, polynomial, and other functions. Mathematica simulations of these solutions confirm that longitudinal displacements in DNA can be expressed as periodic waves, optical dark solitons, singular solutions, exponential forms, and rational forms. This study is novel as it marks the first application of the Lie group method to explore the interaction of DNA molecules.

Effect of Salvadora persica on resin-dentin bond stability.

BACKGROUND: The stability of resin-dentin interfaces is still highly questionable. The aim of this study was to evaluate the effect of Salvadora persica on resin-dentin bond durability. MATERIALS AND METHODS: Extracted human third molars were used to provide mid-coronal dentin, which was treated with 20% Salvadora persica extract for 1 min after acid-etching. Microtensile bond strength and interfacial nanoleakage were evaluated after 24 h and 6 months. A three-point flexure test was used to measure the stiffness of completely demineralized dentin sticks before and after treatment with Salvadora persica extract. The hydroxyproline release test was also used to measure collagen degradation by endogenous dentin proteases. Statistical analysis was performed using two-way ANOVA followed by post hoc Bonferroni test and unpaired t-test. P-values < 0.05 were considered statistically significant. RESULTS: The use of Salvadora persica as an additional primer with etch-and-rinse adhesive did not affect the immediate bond strengths and nanoleakage (p > 0.05). After 6 months, the bond strength of the control group decreased (p = 0.007), and nanoleakage increased (p = 0.006), while Salvadora persica group showed no significant difference in bond strength and nanoleakage compared to their 24 h groups (p > 0.05). Salvadora persica increased dentin stiffness and decreased collagen degradation (p < 0.001) compared to their controls. CONCLUSION: Salvadora persica extract pretreatment of acid-etched dentin preserved resin-dentin bonded interface for 6 months. CLINICAL SIGNIFICANCE: Durability of resin-dentin bonded interfaces is still highly questionable. Endogenous dentinal matrix metalloproteinases play an important role in degradation of dentinal collagen within such interfaces. Salvadora persica may preserve resin-dentin interfaces for longer periods of time contributing to greater clinical success and longevity of resin composite restorations.

Neuro-computing solution for Lorenz differential equations through artificial neural networks integrated with PSO-NNA hybrid meta-heuristic algorithms: a comparative study.

In this article, examine the performance of a physics informed neural networks (PINN) intelligent approach for predicting the solution of non-linear Lorenz differential equations. The main focus resides in the realm of leveraging unsupervised machine learning for the prediction of the Lorenz differential equation associated particle swarm optimization (PSO) hybridization with the neural networks algorithm (NNA) as ANN-PSO-NNA. In particular embark on a comprehensive comparative analysis employing the Lorenz differential equation for proposed approach as test case. The nonlinear Lorenz differential equations stand as a quintessential chaotic system, widely utilized in scientific investigations and behavior of dynamics system. The validation of physics informed neural network (PINN) methodology expands to via multiple independent runs, allowing evaluating the performance of the proposed ANN-PSO-NNA algorithms. Additionally, explore into a comprehensive statistical analysis inclusive metrics including minimum (min), maximum (max), average, standard deviation (S.D) values, and mean squared error (MSE). This evaluation provides found observation into the adeptness of proposed AN-PSO-NNA hybridization approach across multiple runs, ultimately improving the understanding of its utility and efficiency.

Outcomes of primary versus conversional Roux-En-Y gastric bypass after laparoscopic sleeve gastrectomy: a retrospective propensity score-matched cohort study.

BACKGROUND: Conversional surgery is common after laparoscopic sleeve gastrectomy (LSG) because of suboptimal weight loss (SWL) or poor responders and gastroesophageal reflux disease (GERD). Roux-en-Y gastric bypass (RYGB) is the most common conversional procedure after LSG. METHODS: A retrospective cohort study analyzed patients who underwent primary RYGB (PRYGB) or conversional RYGB (CRYGB) at three specialized bariatric centers between 2008 and 2019 and tested for weight loss, resolution of GERD, food tolerance (FT), early and late complications, and the resolution of associated medical problems. This was analyzed by propensity score matching (PSM). RESULTS: In total, 558 (PRYGB) and 155 (CRYGB) completed at least 2 years of follow-up. After PSM, both cohorts significantly decreased BMI from baseline (p < 0.001). The CRYGB group had an initially more significant mean BMI decrease of 6.095 kg/m2 at 6 months of follow-up (p < 0.001), while the PRYGB group had a more significant mean BMI decrease of 5.890 kg/m2 and 8.626 kg/m2 at 1 and 2 years, respectively (p < 0.001). Food tolerance (FT) improved significantly in the CRYGB group (p < 0.001), while CRYGB had better FT than PRYGB at 2 years (p < 0.001). A GERD resolution rate of 92.6% was recorded in the CRYGB (p < 0.001). Both cohorts had comparable rates of early complications (p = 0.584), late complications (p = 0.495), and reoperations (p = 0.398). Associated medical problems at 2 years significantly improved in both cohorts (p < 0.001). CONCLUSIONS: CRYGB is a safe and efficient option in non- or poor responders after LSG, with significant weight loss and improvement in GERD. Moreover, PRYGB and CRYGB had comparable complications, reoperations, and associated medical problem resolution rates.

Local recurrence risk factors and outcomes in minimally invasive thermal ablation for liver tumors: a single-institution analysis.

BACKGROUND: Minimally Invasive thermal ablation (MITA) of liver tumors is a commonly performed procedure, alone or in combination with liver resection. Despite being a first-option strategy for small lesions, it is technically demanding, and many concerns still exist about local disease control. METHODS: Consecutive patients undergoing MITA from 1-2019 to 12-2022 were retrospectively enrolled. Risk factors of local recurrence were investigated through univariate and multivariable cox regression analysis. RESULTS: At the multivariable analysis of the 207 nodules undergoing MITA, RFA was associated with worse local Recurrence Free Survival (lRFS) than MWA (HR 2.87 [95 % CI 0.96-8.66], p = 0.05), as well as a concomitant surgical resection (HR 3.89 [95 % CI 1.06-9.77], p = 0.02). A concomitant surgical resection showed worse lRFS in the subgroup analysis of both HCC (HR 3.98 [95 % CI 1.16-13.62], p = 0.02) and CRLM patients (HR 2.68 [95 % CI 0.66-5.92], p = 0.04). Interestingly, a tumor size between 30 and 40 mm was not associated to worse lRFS. CONCLUSION: MWA may reduce the risk of local recurrence in comparison to RFA, while MITA associated to liver resection may face an increased risk of local recurrence. Further prospective studies are needed to confirm such results.

Revisional One-Step Bariatric Surgical Techniques After Unsuccessful Laparoscopic Gastric Band: A Retrospective Cohort Study with 2-Year Follow-up.

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) has high reported rates of revision due to poor weight loss (WL) and high complication rates. Yet, there is yet to be a consensus on the best revisional procedure after unsuccessful LAGB, and studies comparing different revisional procedures after LAGB are still needed. METHODS: This was a retrospective cohort study that compared the outcomes of one-step revisional Roux-en-Y gastric bypass (rRYGB), one-anastomosis gastric bypass (rOAGB), or laparoscopic sleeve gastrectomy (rLSG) after LAGB. WL, complications, resolution of associated medical conditions, and food tolerance were assessed with a post hoc pairwise comparison one-way analysis of variance (ANOVA) throughout a 2-year follow-up. RESULTS: The final analysis included 102 (rRYGB), 80 (rOAGB), and 70 (rLSG) patients. After 2 years, an equal percentage of excess weight loss was observed in rOAGB and rRYGB (both >90%; p=0.998), significantly higher than that in rLSG (83.6%; p<0.001). In our study, no leaks were observed. rRYGB had higher complication rates according to the Clavien-Dindo classification (10.8% vs. 3.75% and 5.7% in rOAGB and rLSG, respectively, p=0.754), and re-operations were not statistically significant. Food tolerance was comparable between rOAGB and rRYGB (p = 0.987), and both had significantly better food tolerance than rLSG (p<0.001). The study cohorts had comparable resolution rates for associated medical problems (p>0.60). CONCLUSION: rOAGB and rRYGB had better outcomes after LAGB than rLSG regarding WL, feasibility, food tolerance, and safety. rOAGB had significantly higher rates of nutritional deficiencies.

Incidence of persistent SARS-CoV-2 gut infection in patients with a history of COVID-19: Insights from endoscopic examination.

Background and study aims Gut infection is common during acute COVID-19, and persistent SARS-CoV-2 gut infection has been reported months after the initial infection, potentially linked to long-COVID syndrome. This study tested the incidence of persistent gut infection in patients with a history of COVID-19 undergoing endoscopic examination. Patients and methods Endoscopic biopsies were prospectively collected from patients with previous COVID-19 infection undergoing upper or lower gastrointestinal endoscopy (UGE or LGE). Immunohistochemistry was used to detect the presence of persistent SARS-CoV-2 nucleocapsid proteins. Results A total of 166 UGEs and 83 LGE were analyzed. No significant differences were observed between patients with positive and negative immunostaining regarding the number of previous COVID-19 infections, time since the last infection, symptoms, or vaccination status. The incidence of positive immunostaining was significantly higher in UGE biopsies than in LGE biopsies (37.34% vs. 16.87%, P =0.002). Smokers showed a significantly higher incidence of positive immunostaining in the overall cohort and UGE and LGE subgroups ( P <0.001). Diabetic patients exhibited a significantly higher incidence in the overall cohort ( P =0.002) and UGE subgroup ( P =0.022), with a similar trend observed in the LGE subgroup ( P =0.055). Conclusions Gut mucosal tissues can act as a long-term reservoir for SARS-CoV-2, retaining viral particles for months following the primary COVID-19 infection. Smokers and individuals with diabetes may be at an increased risk of persistent viral gut infection. These findings provide insights into the dynamics of SARS-CoV-2 infection in the gut and have implications for further research.

Groundbreaking Dual-Graft Living Donor Liver Transplant Utilizing Full Right and Left Lateral Lobe Grafts: A Landmark Debut in the Kingdom of Saudi Arabia.

We introduce and documentthe first case of dual-graft living donor liver transplant, at the King Fahad Specialist Hospital in Dammam, Kingdom of Saudi Arabia, in which both a full right lobe and a left lateral segment graft were used. Our patient, a 63-year-old male, was diagnosed with nonalcoholic steatohepatitis cirrhosis and hepatocellular carcinoma involving segment 7 and selected for living donor liver transplant. Donor selection, graft volume assessment, surgical planning, procurement, and implantation of the dual grafts were meticulously executed. The first donor had an estimated right lobe volume of 639 mL, yielding an estimated graft-to-recipient weight ratio of 0.68. A liver biopsy revealed 3% macrosteatosis.The second donor's contribution comprised a left lateral segment volume of 280 mL.The decision was made for dual-graft liver transplant. With both grafts, the volume totaled 919 mL, representing graft-torecipient weight ratio of 0.98. Surgical techniques involved anastomoses of hepatic veins, portal veins, arteries, and biliary reconstruction. Both donors and the recipient were closely monitored posttransplant. After the procedure, both donors recovered swiftly and were discharged 4 days postoperation. The recipient experienced a smooth postoperative course, spending 4 days in the intensive care unit and discharged on day 26 posttransplant. This pioneering dual-graft living donor liver transplant showed successful outcomes and highlighted the potential of this approach to expand the limited donor pool, particularly in regions relying predominantly on living donors, like Saudi Arabia. This innovative surgical technique offers a promising solution to address the growing demand for liver transplants while ensuring safety for individual donors and maintaining acceptable recipient outcomes. Further exploration and adoption of dual-graft liver transplant could significantly affectthe field of livertransplant globally.

Managing the Complication of Band Erosion in Banded Sleeve Gastrectomy: A Case Report.

We present a case involving a patient with laparoscopic banded sleeve gastrectomy (BSG) with a 3-month history of persistent vomiting, decreased tolerance for fluids, and limited intake of soft food items. Upon investigation, an eroded band and gastric dilatation were identified. The treatment involved the removal of the eroded band and a segment of the stomach, followed by the restoration of gastric continuity through a gastrogastrostomy.

Understanding the impact of formulation design on microstructure and drug release from porous microparticle-based tretinoin topical gels.

For proportionally formulated intermediate strengths of a topical product, the relationship of drug release across multiple strengths of a given product is not always well understood. The current study aims to assess the proportionality of tretinoin release rates across multiple strengths of tretinoin topical gels when manufactured using two different methods to understand the impact of formulation design on drug product microstructure and tretinoin release rate. Two groups of tretinoin gels of 0.04 %, 0.06 %, 0.08 % and 0.1 % strengths were manufactured. Gels in Group I were prepared by incorporating 4-10 % g/g of 1 % w/w tretinoin-loaded microparticles into a gel base. Gels in Group II were manufactured using 10 % g/g of the microparticles that were loaded with increasing amounts (0.4-1 % w/w) of tretinoin. The two groups of gels were characterized by evaluating microstructure using a polarized microscope, rheology using an oscillatory rheometer, and drug release using Vison® Microette™ Hanson vertical diffusion cells. The microscopic images were used to discriminate between the two groups of gels based on the abundance of microparticles in the gel matrix observed in the images. This abundance increased across gels of Group I and was similar across gels of Group II. The rheology parameters, namely viscosity at a shear rate of 10 s-1, shear thinning rate, storage, and loss modulus, increased across gels of Group I, and were not significantly different across gels of Group II. The release rate of tretinoin from the drug products was proportional to the nominal strength of the drug product in both Group I and Group II, with a correlation coefficient of 0.95 in each case, although the absolute release rates differed. Overall, changing the formulation design of tretinoin topical gels containing porous microparticles may change the physicochemical and structural properties, as well as the drug release rate of the product. Further, keeping the formulation design consistent across all strengths of microparticle-based topical gels is important to achieve proportional release rates across multiple strengths of a given drug product.

Comparison of Histological Skin Changes After Massive Weight Loss in Post-bariatric and Non-bariatric Patients.

BACKGROUND: Changes in the skin structure, including the collagen and elastin content, have been reported with massive weight loss (MWL) following bariatric metabolic surgery (BMS) and have been correlated to a higher risk of complications after body-contouring surgery (BCS). This study aimed at comparing the histological characteristics of the skin of patients having surgical MWL (SMWL) post-BMS to those with non-surgical massive weight loss (NSMWL). METHODS: This prospective study compared the epidermal thickness, and collagen and elastin fibers content in 80 skin biopsies obtained from BCS procedures performed to patients who experienced MWL defined more than 50% of excess weight loss (%EWL) either SMWL (40 biopsies) or NSMWL (40 biopsies). Twenty biopsies in each group were obtained from abdominoplasties and 20 from breast reductions. Epidermal thickness was measured in H&E-stained sections, collagen fibers were assessed using Masson trichrome-stained sections, and elastin fibers were assessed using Modified Verhoeff's stained sections. Image analysis software was used to calculate the fractions of collagen and elastin fibers. RESULTS: This study included 77 patients, 38 SMWL patients, and 39 NSMWL patients. The SMWL group had a significantly higher age (p < 0.001), a longer time interval from intervention (p < 0.001), higher initial weight (p < 0.001), higher initial BMI (p < 0.001), lower current weight (p = 0.005), lower current BMI (p < 0.001), and significantly higher %EWL than NSMWL group (p < 0.001). No significant differences were detected between the two groups regarding complications after abdominoplasty (p = 1.000). The elastic fibers content in the dermis was significantly higher in the abdominal region of the NSMWL group than SMWL (p = 0.029). All other parameters showed non-significant differences between NSMWL and SMWL in the skin of abdomen and breast. CONCLUSION: The SMWL group had a significant reduction in elastic fiber content in the skin of the abdomen compared to the NSMWL group. The collagen content was equally reduced in both groups with non-significant differences in both breast and abdomen regions in both groups.

Characterizing a design space for a twin-screw wet granulation process: A case study of extended-release tablets.

Twin-screw wet granulation is an emerging continuous manufacturing technology for solid oral dosage forms. This technology has been successfully employed for the commercial manufacture of immediate-released tablets. However, the higher polymer content in extended-release (ER) formulations may present challenges in developing and operating within a desired design space. The work described here used a systematic approach for defining the optimum design space by understanding the effects of the screw design, operating parameters, and their interactions on the critical characteristics of granules and ER tablets. The impacts of screw speed, powder feeding rate, and the number of kneading (KEs) and sizing elements on granules and tablets characteristics were investigated by employing a definitive screening design. A semi-mechanistic model was used to calculate the residence time distribution parameters and validated using the tracers. The results showed that an increase in screw speed decreased the mean residence time of the material within the barrel, while an increase in the powder feeding rate or number of KEs did the opposite and increased the barrel residence time. Screw design and operating parameters affected the flow and bulk characteristics of granules. The screw speed was the most significant factor impacting the tablet's breaking strength. The dissolution profiles revealed that granule characteristics mainly influenced the early phase of drug release. This study demonstrated that a simultaneous optimization of both operating and screw design parameters was beneficial in producing ER granules and tablets of desired performance characteristics while mitigating any failure risks, such as swelling during processing.

Boosting weight loss after conversional Roux-en-Y Gastric Bypass with liraglutide and placebo use. A double-blind-randomized controlled trial.

BACKGROUND: Conversional bariatric surgery inherently has less weight loss (WL) compared to primary procedures. Adjunctive use of the GLP-1 analog, liraglutide with conversional Roux-en-Y Gastric Bypass (cRYGB) may maximize the WL benefits of surgery. MATERIAL AND METHODS: This single-center randomized double-blind placebo-controlled trial included 80 patients randomized into two groups; the liraglutide group (40 patients) who received daily injections of liraglutide, and the placebo group (40 patients) who received normal saline starting at 6 weeks from cRYGB and continued for 6 months. After discontinuing the drugs at 6 months and unblinding, the patient were followed up to 12 months. The endpoints were percentage of total weight loss (%TWL) and percentage of excess weight loss (%EWL), and changes in the metabolic biomarkers, and complications within 30 and 90 days according to the global outcome benchmark (GOB) stratification. RESULTS: In total, 38 patients in the liraglutide group and 31 in the placebo group completed the 24 weeks. Liraglutide group experienced better WL with a significantly higher mean %TWL at 1 month (10.27±1.39 vs. 8.41±2.08), at 6 weeks (12.65±1.77 vs. 10.47±2.23), at 6 months (18.29 ±1.74 vs. 15.58 ±1.65), and at 12 months 24.15±2.35 versus 22.70±2.13 (all P <0.001). For %EWL, this was also significantly higher in the liraglutide group at all time points. A %TWL of greater than 20% at 6 months of treatment was recorded in six (15.8%) patients in the liraglutide group and none in the placebo group ( P =0.029). Both groups had comparable changes in metabolic biomarkers. Adverse events were recorded in 11 (27.5%) patients in the liraglutide, with no adverse events in the placebo group ( P <0.001). Both groups had Clavien-Dindo scores I and II (5.0 and 2.5%), and GOB values indicated that 90.0 and 97.5% were low-risk patients. CONCLUSION: Adjunctive use of liraglutide with cRYGB gives significantly higher WL and resolution of associated medical problems.

Recent advances in three-dimensional ultrasound virtual cystoscopy in modeling and local staging for urothelial carcinoma with histopathological correlation: a cohort prospective study.

Background: Bladder urothelial carcinoma is an alarming urologic malignancy. Complex factors like modelling and local staging can affect treatment strategy. However, local staging, particularly the muscle invasion status, significantly influences decisions regarding treatment strategies. Therefore, this study aims to evaluate the novel advances of three-dimensional (3D) ultrasound (US) imaging to assess local staging in comparison with conventional cystoscopy. Methods: Forty-three patients with painless haematuria and conventional cystoscopy findings of bladder mass underwent 3D US virtual cystoscopy. All specimens from conventional cystoscopy were processed histologically. Results: Out of 43 participants, 18 (41.9%) patients proved to have invasive urothelial carcinoma by histopathology. The 3D US had a sensitivity of 97.5% and a specificity of 100%; however conventional cystoscopy was accurate in only 53.5% of the studied cases. Furthermore, in the case of malignant ulcers, mural extension into both the submucosal and the muscle layers was more readily appreciated in multiplanar images. Conclusion: 3D US updates are promising for use in bladder tumour modelling and local staging; however, they can be of value in evaluating mural and extramural tumour extent and have proven accuracy.

Two-Year Results of the Banded Versus Non-banded Re-sleeve Gastrectomy as a Secondary Weight Loss Procedure After the Failure of Primary Sleeve Gastrectomy: a Randomized Controlled Trial.

BACKGROUND: Insufficient weight loss or weight regain has been reported in up to 30% of patients after laparoscopic sleeve gastrectomy (LSG). Approximately 4.5% of patients who undergo LSG need revisional surgery for a dilated sleeve. METHODS: This randomized controlled trial compared the outcomes between banded (BLSG) and non-banded re-LSG (NBLSG) after weight regain. Percentage excess body weight loss (%EWL), percentage total weight loss (%TWL), associated medical problems, gastric volume measurement, and endoscopy were measured preoperatively and 1 and 2 years postoperatively. RESULTS: Both groups (25 patients each) achieved similar % EWL and %TWL at six months, one year, and two years postoperatively (%EWL 46.9 vs. 43.6, 83.7 vs. 86.3, and 85.7 vs. 83.9) (p= > 0.151) (%TWL 23.9 vs. 21.8, 43.1 vs .43.3, 44.2 vs. 42.2) (p=>0.342), respectively. However, the body mass index was significantly lower with BLSG (24.9 vs. NBLSG, 26.9). Both groups showed a significant reduction in stomach volume after two years (BLSG -248.4 mL vs. NBLSG -215.8 mL). Food tolerance (FT) scores were significantly reduced in both groups, whereby BSLG had significantly lower FT with an average of -1.1 point. No significant differences were observed regarding improvement of the associated medical problems after the first and two years after revisional LSG or the postoperative complications between both groups. CONCLUSION: Laparoscopic re-LSG is feasible and safe with satisfactory outcomes in patients with weight regain after LSG who have gastric dilatation without reflux esophagitis. Both groups had comparable significant weight loss effects and improvement of associated medical problems. The BLSG tends to have a more stable weight loss after two years with a significantly lower BMI, lower stomach volume, and less weight regain. Food tolerance decreased in both groups but reduced more in the BLSG group. After a 2-year follow-up, we may regard both procedures are safe, with no significant differences in the occurrence of complications and nutritional deficits.

How Good is Stratification and Prediction Model Analysis Between Primary and Revisional Roux-en-Y Gastric Bypass Surgery? A Multi-center Study and Narrative Review.

INTRODUCTIONS: Revision surgery because of weight recurrence is performed in 2.5-33% of primary vertical banded gastroplasty (VBG), laparoscopic sleeve gastrectomy (LSG), and gastric band (GB) cases. These cases qualify for revisional Roux-en-Y gastric bypass (RRYGB). METHODS: This retrospective cohort study analyzed data from 2008 to 2019. A stratification analysis and multivariate logistic regression for prediction modeling compared the possibility of sufficient % excess weight loss (%EWL) ≥ 50 or insufficient %EWL < 50 between three different RRYGB procedures, with primary Roux-en-Y gastric bypass (PRYGB) as the control during 2 years of follow-up. A narrative review was conducted to test the presence of prediction models in the literature and their internal and external validity. RESULTS: A total of 558 patients underwent PRYGB, and 338 underwent RRYGB after VBG, LSG, and GB, and completed 2 years of follow-up. Overall, 32.2% of patients after RRYGB had a sufficient %EWL ≥ 50 after 2 years, compared to 71.3% after PRYGB (p ≤ 0.001). The total %EWL after the revision surgeries for VBG, LSG, and GB was 68.5%, 74.2%, and 64.1%, respectively (p ≤ 0.001). After correcting for confounding factors, the baseline odds ratio (OR) or sufficient %EWL ≥ 50 after PRYGB, LSG, VBG, and GB was 2.4, 1.45, 0.29, and 0.32, respectively (p ≤ 0.001). Age was the only significant variable in the prediction model (p = 0.0016). It was impossible to develop a validated model after revision surgery because of the differences between stratification and the prediction model. The narrative review showed only 10.2% presence of validation in the prediction models, and 52.5% had external validation. CONCLUSION: Overall, 32.2% of all patients after revisional surgery had a sufficient %EWL ≥ 50 after 2 years, compared to PRYGB. LSG had the best outcome in the revisional surgery group in the sufficient %EWL group and the best outcome in the insufficient %EWL group. The skewness between the prediction model and stratification resulted in a partially non-functional prediction model.