Second-stage Surgery Research Articles

Repeat two-stage exchange arthroplasty for recurrent periprosthetic hip or knee infection: what are the chances for success?

IntroductionTwo-stage revision is a frequently chosen approach to treat chronic periprosthetic joint infection (PJI). However, management of recurrent infection after a two-stage exchange remains debated and the outcome of a repeat two-stage procedure is unclear. This study investigates the success rates of repeat two-stage exchange arthroplasty and analyzes possible risk factors for failure.Materials and methodsWe retrospectively identified 55 patients (23 hips, 32 knees) who were treated with repeat resection arthroplasty and planned delayed reimplantation for recurrent periprosthetic joint infection between 2010 and 2019 after a prior two-stage revision at the same institution. The minimum follow-up was 12 months with a median follow-up time of 34 months (IQR 22–51). The infection-free survival, associated revision surgeries, and potential risk factors for further revision were analyzed using Kaplan–Meier survival curves and comparative non-parametric testing.Results78% (43/55) underwent reimplantation after a repeat implant removal. Of those who completed the second-stage surgery, 37% (16/43) underwent additional revision for infection and 14% (6/55) underwent amputation. The reinfection-free implant survivorship amounted to 77% (95% CI 64–89%) after 1 year and 38% (95% CI 18–57%) after 5 years. Patients with a higher comorbidity score were less likely to undergo second-stage reimplantation (median 5 vs. 3, p = 0.034). Furthermore, obese patients (p = 0.026, Fisher’s exact test) and diabetics (p < 0.001, log-rank test) had a higher risk for further infection. Most commonly cultures yielded polymicrobial growth at the repeat two-stage exchange (27%, 15/55) and at re-reinfection (32%, 9/28). Pathogen persistence was observed in 21% (6/28) of re-reinfected patients.ConclusionThe success rates after repeat two-stage exchange arthroplasty are low. Patients must be counseled accordingly and different modes of treatment should be considered.

Role of crenel lateral lumbar interbody fusion in the precise selection of fusion level in posterior correction for adult degenerative scoliosis

Objective: To investigate the role of minimally invasive crenel lateral lumbar interbody fusion (CLIF) in the decision of fusion level in posterior correction for severe adult degenerative scoliosis. Methods: This is a prospective study.Patients with level Ⅴ and Ⅵ of Lenke-Silva classification who were treated at Department of Orthopedics,the Second Affiliated Hospital, School of Medicine, Zhejiang University from June 2016 to March 2019 were included.First,the enrolled patients completed the preoperative clinical and imaging examination,the Lenke-Silva classification was evaluated,the surgical segments in first-stage CLIF was determined and the fusion segments required for single-stage posterior correction was predicted.After the first-stage CLIF,patients received reassessment of Lenke-Silva classification and global coronal and sagittal balance.Patients were divided into two groups:the effective group (level of Lenke-Silva classification decreased) and the ineffective group (level of Lenke-Silva classification unchanged).Second-stage posterior surgery was performed based on the results of reassessments.The fusion segment,Cobb angle,parameters of global coronal and sagittal plane,visual analogue pain score (VAS) and Oswestry disability index (ODI) were compared between the two groups preoperatively,after first-stage CLIF,second-stage posterior fixation and at the final follow-up.The potential factors associated with the decrease of the level of Lenke-Silva classification were recorded and compared between the two groups.Independent sample t test,repeated measure analysis of variance,rank sum test,χ2 test or Fisher exact method were used to compare the difference among groups. Results: Fifty-four patients were enrolled,including 8 males and 46 females,aged (68.8±5.8) years (range:56 to 77 years).Preoperatively,26 patients were classified as level Ⅴ by Lenke-Silva classification,28 cases were grade Ⅵ.CLIF was performed in 194 segments,with 114 segments(58.8%) receiving anterior column realignment (ACR) and 15 segments(7.7%) using hyperlordotic cages.After first-stage CLIF,22 patients with level Ⅴ and 10 patients with Ⅵ of Lenke-Silva classification decreased and were classified into effective group.The level of the remaining 4 patients with level Ⅴ and 18 patients with grade Ⅵ unchanged and were classified into ineffective group.Preoperatively,the apical vertebrae was below L1 in all 32 patients of effective group and 18 (81.8%,18/22) patients of ineffective group.The difference was statistically significant (P=0.023).There were 7 (31.8%,7/22) patients had continuous osteophyte in front of the intervertebral space in ineffective group,while none patient had continuous osteophyte in front of the intervertebral space in effective group,and the difference was statistically significant (P=0.001).In first-stage CLIF,more intraoperative ACR(71.2% vs.39.5%,χ²=20.660,P<0.01)and hyperlordotic cage (12.7% vs.0,P=0.001) were used in the effective group,while there was less severe cage subsidence after the operation (5.9% vs.15.8%,χ²=4.793,P=0.029) in effective group.After first-stage CLIF,there was no difference in the Cobb angle between the two groups.While,lumbar lordosis (LL) in effective group (34.0±8.3)° was greater than that of the ineffective group (25.5±9.7)° (t=3.478,P=0.001),and the difference between the pelvic incidence (PI) and LL in effective group (15.7±4.6)°was significantly smaller than ineffective group(20.0±10.8)° (t=-2.129,P=0.038).The posterior fusion levels was less,the rate of fusion to thoracic spine region and the actual fusion segment was less than that of single-stage posterior correction in effective group (all P<0.01).All patients were follow-up for 24 to 45 months.There was no significant difference in radiological and clinical results between the two groups after first-,second-stage surgery and at the final follow-up (all P>0.05). Conclusions: First-stage CLIF decreased the Lenke-Silva classification of some patients with severe degenerative scoliosis.Combined with the reassessment of Lenke-Silva classification and global coronal and sagittal plane,it helps to accurately determine the fusion segment.Decrease of Lenke-Silva classification is associated with the preoperative level of apical vertebrae,continuous osteophytes in front of the intervertebral space,intraoperative use of ACR and hyperlordotic cage and the degree of cage subsidence postoperatively.

АГЕНЕЗИЯ ДИАФРАГМЫ: ОПИСАНИЕ КЛИНИЧЕСКОГО СЛУЧАЯ И КРАТКИЙ ОБЗОР ЛИТЕРАТУРЫ

Objective: Agenesis of the diaphragm (AD) in adults is an extremely rare congenital malformation. To date, only a few descriptions of this pathology have been published in the scientific literature. The article presents a case of detection of a left-sided AD in a 25-year-old patient operated on for diaphragmatic relaxation. Additional examination methods, including echocardiography and ultrasonography of the abdominal organs and retroperitoneal space, did not reveal any other malformations in this patient. Due to the lack of plastic material of the appropriate size and type, plastic replacement of the diaphragm was postponed to the second stage of surgery. Keywords: Congenital malformations, anomalies of the diaphragm, aplasia of the diaphragm, agenesis of the diaphragm, agenesis of the diaphragm in adults, diaphragmatic hernia, plastic surgery of the diaphragm.

Antibiotic Therapy in 2-Stage Revision for Periprosthetic Joint Infection: A Systematic Review.

Patients undergoing total joint arthroplasty (TJA) are at risk for developing periprosthetic joint infection (PJI). To treat PJI, orthopaedic surgeons can perform 1-stage or 2-stage revision arthroplasty. Although 2-stage revision yields superior long-term outcomes, the optimal antibiotic therapy duration and route of administration between stages remain uncertain. In this systematic review, we aimed to identify if variations in antibiotic therapy, duration, and administration during 2-stage hip or knee revision arthroplasty affect PJI eradication rates and surgical outcome measures. A literature search was performed using the PubMed and Google Scholar databases to identify all original reports from January 2000 to June 2021 involving 2-stage revision arthroplasty to treat PJI. Studies were included if they specified antibiotic duration, an intravenous (IV) route of antibiotic administration, type of antibiotic, and 2-stage revision PJI eradication rate and had a mean or median follow-up of at least 2 years after the second-stage operation. Included studies were classified into 3 groups based on the length of IV antibiotic therapy after prosthesis explantation: prolonged IV antibiotic therapy of 4 to 6 weeks, shortened IV antibiotic therapy of ≤2 weeks, and shortened course of IV antibiotic therapy followed by 6 to 12 weeks of oral antibiotics. Nine studies were included. Three studies utilizing a prolonged IV antibiotic therapy had PJI eradication rates of 79% to 96%. Four studies using a shortened IV antibiotic therapy showed PJI eradication rates of 88% to 100%. Finally, 2 studies utilizing a shortened course of IV antibiotic therapy with oral antibiotics had PJI eradication rates of 95% and 97%. There was no significant difference in eradication rates across IV antibiotic duration strategies, despite a diverse array of cultured microorganisms across the studies. Although the numbers are small, this systematic review suggests that prolonged IV antibiotic duration, shortened IV antibiotic duration, and shortened IV antibiotic duration supplemented with oral antibiotics confer similar PJI eradication rates after hip or knee arthroplasty. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Second-Stage Surgery for Thoracoabdominal Aortic Aneurysm after Ascending Aorta-Abdominal Aorta Bypass for Atypical Coarctation Due to Takayasu Arteritis

Although aortic aneurysms associated with Takayasu arteritis are not rare, a total occlusion of the thoracoabdominal aorta with enlargement is rare. We have experienced a 60-year-old man who underwent a second-stage surgery for thoracoabdominal aortic aneurysm nine years after the prior operation of an ascending aorta-abdominal aorta bypass for atypical coarctation due to Takayasu arteritis. We present a successful case of the treatment result after 4 years’ follow-up.

Simultaneous Anterior and Posterior Release in Lateral Decubitus Position for Rigid Adult Spinal Deformity: A Technical Note and 2 Case Reports

Correction surgery for rigid adult spinal deformity usually involves a complex 360° osteotomy, multiple intraoperative position changes, and staged surgery. Moreover, there is a lack of consensus regarding the surgical strategy for this pathology. We report the technical advantages of a simultaneous anterior and posterior release only in the lateral decubitus position to reduce surgical invasiveness in two case reports. A 76-year-old woman and an 80-year-old woman presented with significant spinal imbalance and segmental fusion in the anterior and posterior columns around the apex of the lumbar spinal curvature. We conducted this procedure for these patients at the first stage of spinal corrective surgery to achieve 360° osteotomy. A long posterior fusion surgery was performed after 1 week. The mean values of the central sacral vertical line, pelvic incidence minus lumbar lordosis, sagittal vertical axis, and pelvic tilt improved substantially postoperatively: central sacral vertical line, from 51.0 to 7.5 mm; pelvic incidence minus lumbar lordosis, from 27.5° to 0.5°, sagittal vertical axis, from 107.6 to 14 mm; pelvic tilt, from 34.0° to 13.0°. The mean surgical time and blood loss in the first- and second-stage operations were 242.1 minutes and 702 mL and 315.5 minutes and 549 mL, respectively, and no perioperative complications occurred. Simultaneous 360° segmental release in the lateral decubitus position without repositioning can make it possible to acquire satisfactory correction and reduce surgical invasiveness compared with the conventional procedure for adult spinal deformity.

Features of treatment of severe acute pancreatitis in obese patients

The purpose of the work is to improve the results of treatment of severe acute pancreatitis in obese patients and to develop an algorithm for comprehensive treatment. Materials and methods. Patients with severe acute pancreatitis and obesity (mean BMI 37.48 ± 2.19 kg/m2) were randomized into two groups. In the experimental group (n = 18; step-up approach),early resuscitation with Ringer's lactate solution and ulinastatin in the first 5 days of the disease was used. Unilastatin was administered at a dose of 200,000IU by 1-hourintra­venous infusion TID for 5 days. The first stage of surgery was a drainage under ultrasound control, the second stage (if necessary) was laparos­copic retroperitoneal necrectomy (video-assisted­retroperitoneal debri­de­ment — VARD). Open surgery was performed in case of development of abdominal compartment syndrome. In the control group (n = 18; standard approach), resuscita­tion was performed with 0.9 % sodium chlo­ride solution without ulinastatin. The first stage of surgery was draina­ge under ultrasound control, the second stage was traditional median laparotomy with laparostomy. Results. The use of resuscitation with Ringer’s lactate solution in combination with ulinastatin for 5 days contributed to a decrease of procalcitoninlevels by 1.8 times (2.89 ± 0.88 compared with 1.8 ± 0.23 ng/mg; p = 0.001; α = 0.05). The level of CRP during the period of ulinastatin decreased by 41.68 mg/l (267.28 ± 114.11 compared with 225.6 ± 84.9 mg/l; p = 0.01; α = 0.05). There was a statistically significant difference in procalcitonin levels between groups on the 10th day (1.83 compared with 3.32 ng/mg; p = 0.001; α = 0.05), on the 15th day (1.15 compared with 1 .83 ng/mg; p = 0.001; α = 0.05) and on the 45th day (0.35 compared with 0.55 ng/mg; p = 0.001; α = 0.05). These results confirm the effect of the proposed method of treatment by reducing the risk of infection. Conclusions. The effectiveness of the proposed treatment algorithm is evidenced by a statistically significant difference in the level of CRP between groups on the 10th day (p = 0.035; α = 0.05). The use of VARD in the experimental group as a second stage of surgery is a less traumatic but effective method (p = 0.001; α = 0.05), which reduces the total number of complications (χ² = 4.012; p = 0.046). Evaluation of data «before—after» revealed the effectiveness of treatment by step-up approach (χ² = 5.4; p = 0.021).

Molecular Response to Nanopatterned Implants in the Human Jaw Bone.

Implant surface modification by nanopatterning is an interesting route for enhancing osseointegration in humans. Herein, the molecular response to an intentional, controlled nanotopography pattern superimposed on screw-shaped titanium implants is investigated in human bone. When clinical implants are installed, additional two mini-implants, one with a machined surface (M) and one with a machined surface superimposed with a hemispherical nanopattern (MN), are installed in the posterior maxilla. In the second-stage surgery, after 6–8 weeks, the mini-implants are retrieved by unscrewing, and the implant-adherent cells are subjected to gene expression analysis using quantitative polymerase chain reaction (qPCR). Compared to those adherent to the machined (M) implants, the cells adherent to the nanopatterned (MN) implants demonstrate significant upregulation (1.8- to 2-fold) of bone-related genes (RUNX2, ALP, and OC). No significant differences are observed in the expression of the analyzed inflammatory and remodeling genes. Correlation analysis reveals that older patient age is associated with increased expression of proinflammatory cytokines (TNF-α and MCP-1) on the machined implants and decreased expression of pro-osteogenic factor (BMP-2) on the nanopatterned implants. Controlled nanotopography, in the form of hemispherical 60 nm protrusions, promotes gene expressions related to early osteogenic differentiation and osteoblastic activity in implant-adherent cells in the human jaw bone.

Staged transverse preputial island flap urethroplasty for some proximal hypospadias with moderate-to-severe chordee

BackgroundWe aimed to assess the outcome of staged transverse preputial island flap (TPIF) urethroplasty for repairing certain cases of primary proximal hypospadias with moderate-to-severe chordee in children.MethodsNighty-two consecutive boys who underwent either one-stage or staged TPIF urethroplasty for the repair of proximal hypospadias with moderate-to-severe chordee between August 2015 and December 2019 were evaluated retrospectively. Patients were divided into two groups: one-stage TPIF urethroplasty group (n = 44) and staged TPIF urethroplasty group (n = 48). We noted and compared the postoperative complications, including urethrocutaneous fistula, urethral diverticula, residual penile curvature, and urethral stricture in both groups.ResultsBoth groups were followed up for 1–5 years, with an average of 3 years. No cases of residual or recurrence of penile chordee were reported in either group. In Group A, 9 patients (9/44, 20.4%) had postoperative urethrocutaneous fistula, and all patients underwent urinary fistula repair or urethroplasty. In Group B, postoperative urethrocutaneous fistula occurred in 2 cases (2/48, 4.1%), and one patient developed a urethrocutaneous fistula after the first operation, which was successfully repaired during the second operation. A urethrocutaneous fistula occurred in 1 case after completion of the second-stage operation; urethral fistula repair was performed successfully 6 months later. There were 2 cases of urethral stricture in Group A (2/44, 4.5%) and none in Group B. There were 6 cases of urethral diverticulum in Group A (6/44, 13.6%) and no cases of urethral diverticulum in Group B. The operative success rates were 61.3% and 95.8% in Group A and Group B, respectively (P < 0.001).ConclusionsCompared with one-stage TPIF urethroplasty, staged TPIF urethroplasty in the treatment of certain cases of primary proximal hypospadias with moderate-to-severe chordee resulted in fewer postoperative fistulas, urethral strictures and urethral diverticula. The staged TPIF urethroplasty procedure was effective in reducing the operation difficulty and complication rate of hypospadias, improving the curative effect of complex hypospadias and having good clinical application value.

Short-Term Evaluation of Guided Bone Reconstruction with Titanium Mesh Membranes and CGF Membranes in Immediate Implantation of Anterior Maxillary Tooth.

Purpose The aim of the present prospective study was to evaluate the effect of titanium mesh and concentrated growth factor (CGF) membranes in reconstructing severe labial bone defects during immediate implantation of anterior maxillary tooth. Methods Patients with severe defects presenting on the anterior labial bone plate of maxillary were enrolled in this study. During immediate implantation, the titanium mesh was used to maintain the space of bone graft, collagen membrane, and xenograft bone that were used to guide bone regeneration (GBR). Cone beam computed tomography (CBCT) was used to measure the height and the labial bone thickness around the implant at the time of the second stage surgery, 6 months, 1 year, and 2 years after restoration. The pink esthetic score (PES) was used to evaluate the esthetic outcomes after restoration. Results 18 patients were enrolled in this study. The survival rate of implants was 100%, and no complication was observed, except for 1 case of titanium mesh exposure which did not affect osteogenesis. In the second stage of surgery, the labial bone was completely reconstructed, and the top of the implant was covered with a small amount of new bone. The thickness of the labial bone was 3.01 mm (±0.23), 2.96 mm (±0.21), 2.93 mm (±0.19), and 2.92 mm (±0.16) at the time of the second stage surgery, 6 months, 1 year, and 2 years after restoration, respectively. The height of the marginal bone around implants was above the top of implant at the time of the second stage surgery and then reduced 0.72 mm (±0.07), 0.91 mm (±0.08), and 0.90 mm (±0.07) at the time point of 6 months, 1 year, and 2 years after restoration, respectively. The changes of bone thickness and height were statistically significant within one year, but stable after one year. The PES values showed the same tendency. Conclusions With the limitation of the present prospective study, the combination of titanium mesh and CGF membrane could provide space maintenance for bone augmentation of alveolar bone defects and improve the bone regeneration in patients with severe labial bone defect when immediate implant of anterior maxillary.

Hard tissue stability after guided bone regeneration: a comparison between digital titanium mesh and resorbable membrane

Guided bone regeneration (GBR) uses resorbable and non-resorbable membranes as biological barriers. This study compared the differences in hard tissue stability between GBR using evidence-based digital titanium mesh and resorbable collagen membranes during implant placement. A total of 40 patients (65 implant sites) were enrolled and divided into two groups: resorbable membrane and digital titanium mesh groups. The alveolar bone was analyzed at two- and three-dimensional levels using cone-beam computed tomography and by reconstructing and superimposing the hard tissues at four time points: preoperatively, postoperatively, before second-stage surgery, and 1 year after loading. The use of digital titanium mesh showed less alveolar bone resorption in vertical and horizontal directions two-dimensionally before the second-stage surgery and 1 year after loading. Regarding volumetric stability, the percentage of resorption after 6 months of healing with resorbable membrane coverage reached 37.5%. However, it was only 23.4% with titanium mesh. Although postoperative bone volume was greater at all labial sites with resorbable membrane than with digital titanium mesh, after substantial bone resorption within 1 year of loading, the labial bone thickness at the upper part of implants was thinner with resorbable membrane than with digital titanium mesh. Furthermore, digital titanium meshes made according to ideal bone arch contour reduced soft tissue irritation, and the exposure rate was only 10%. Therefore, although both resorbable membrane and digital titanium mesh in GBR were able to successfully reconstruct the bone defect, digital titanium meshes were better at maintaining the hard tissue volume in the osteogenic space.

Implant Placement With Graftless Sinus Floor Elevation via the Lateral Approach: A Case Series With 4 Years Post-Loading Radiographical Outcomes and Implant Survival Rate.

The purpose of the present study was to evaluate the radiographical outcomes, survival rate, and amount of bone formation around implants placed during graftless lateral sinus lift approach (GLSLA). Five patients (6 sinus augmentations) were consecutively treated with GLSLA. After Schneiderian membrane elevation and implant insertion, only blood clot was left to fill the new sinus compartment. After 4 months of healing, implants were functionally loaded. in all cases, samples were taken for biopsy at the time of second-stage surgery. The radiographical marginal bone variations and apical bone gain were assessed using cone beam- computed tomography taken 4 months after the surgery (at crown insertion) and after 4 years of loading. A total of 14 implants were placed in a mean initial residual bone height of 3.1 mm (range 1.64 mm). No failure was recorded, and all the implants were successfully loaded yielding a 100% survival rate. Vital bone formation was 33% according to the histomorphometry data. Four years after loading the mean radiographic bone remodeling was 1.3 mm. The mean ridge height was 7.6 mm and the mean apical bone gain amounted for 3.8mm. Within the limitations of this study, the placement of dental implants in conjunction with GLSLA seems to be feasible and accompanied by high implant survival rate.

Rescue Partial ALPPS for Left Hemihepatectomy with Reconstruction of the Middle Hepatic Vein

Major hepatectomy in patients with insufficient future liver remnant (FLR) volume and impaired liver functional reserve has considerable risks for posthepatectomy liver failure (PHLF). The patient was a male in his 70s with an intrahepatic cholangiocarcinoma in left hemiliver, involving the middle hepatic vein (MHV). Although FLR volume after left hemihepatectomy was estimated to be 64.4% of the total liver volume, an indocyanine green retention rate at 15 min (ICG-R15) value was 24.2%, thus the patient underwent left portal vein embolization. The FLR volume increased to 71.3%; however, the noncongestive FLR volume was re-estimated as 45.8% after resection of the MHV, the ICG-R15 value was 29.0%, and ICG-Krem was calculated as 0.037. We performed partial rescue Associating Liver Partition and Portal vein occlusion for Staged hepatectomy (ALPPS) for left hemihepatectomy with the MHV reconstruction. On the first stage, partial liver partition was done along Rex-Cantlie’s line, preserving the MHV and sacrificing the remaining branches to segment 8. The FLR volume increased to 77.4% on day 14. The ICG-R15 value was 29.6%, but ICG-Krem after MHV reconstruction was estimated to be 0.059. The second-stage operation on day 21 was left hemihepatectomy with the MHV reconstruction using the left superficial femoral vein graft. The usage of rescue partial ALPPS may contribute to preventing PHLF by introducing occlusion of the portal and/or venous branches in the left hemiliver before curative hepatectomy.

Rate of stoma formation following damage-control surgery for severe intra-abdominal sepsis: a single-centre consecutive case series.

BackgroundSevere intra-abdominal sepsis (IAS) is associated with high mortality and stoma rates. A two-stage approach with initial damage-control surgery (DCS) and subsequent reconstruction might decrease stoma and mortality rates but requires standardization.MethodsA standardized two-stage damage-control algorithm for IAS was implemented in April 2016 and applied systematically.ResultsSome 203 consecutive patients (median age 70 years, 62 per cent ASA score greater than 3) had DCS for severe IAS. Median operation time was 82 minutes, 60 per cent performed during night-time. Median intraoperative noradrenaline doses were 20 (i.q.r. 26) µg/min and blood gas analysis (ABG) was abnormal (metabolic acidosis) in 90 per cent of patients. The second-stage operation allowed definitive surgery in 76 per cent of patients, 24 per cent had up to four re-DCSs until definitive surgery. The in-hospital mortality rate was 26 per cent. At hospital discharge, 65 per cent of patients were stoma free. Risk factors for in-hospital death were noradrenaline (odds ratio 4.25 (95 per cent c.i. 1.72 to 12.83)), abnormal ABG (pH: odds ratio 2.72 (1.24 to 6.65); lactate: odds ratio 6.77 (3.20 to 15.78)), male gender (odds ratio 2.40 (1.24 to 4.85)), ASA score greater than 3 (odds ratio 5.75 (2.58 to 14.68)), mesenteric ischaemia (odds ratio 3.27 (1.71 to 6.46)) and type of resection (odds ratio 2.95 (1.24 to 8.21)). Risk factors for stoma at discharge were ASA score greater than 3 (odds ratio 2.76 (95 per cent c.i. 1.38 to 5.73)), type of resection (odds ratio 30.91 (6.29 to 559.3)) and longer operation time (odds ratio 2.441 (1.22 to 5.06)).ConclusionInitial DCS followed by secondary reconstruction of bowel continuity for IAS within 48 hours in a tertiary teaching hospital was feasible and safe, following a clear algorithm.

Multi-objective optimization of a power-to-hydrogen system for mobility via two-stage stochastic programming

A systematic way for the optimal design of renewable-based hydrogen refuelling stations in the presence of uncertainty in the hydrogen demand is presented. A two-stage stochastic programming approach is used to simultaneously minimize the total annual cost and the CO2 footprint due to the electricity generation sources. The first-stage (design) variables correspond to the sizing of the devices, while the second-stage (operation) variables correspond to the scheduling of the installed system that is affected by uncertainties. The demand of a fleet of fuel cell vehicles is synthesized by means of a Poisson distribution and different scenarios are generated by random sampling. We formulate our problem as a large-scale mixed-integer linear program and we rely on a two-level approximation scheme to keep the problem computationally tractable. A solely deterministic setting which does not take into account uncertainties leads to underestimated device sizes, resulting in a significant fraction of demand remaining unserved with a consequent loss in revenue. The multi-objective optimization produces a convex Pareto front, showing that a reduction in carbon footprint comes with increasing costs and thus diminishing profit.

COVID-19 Collateral Damage: Management of Periprosthetic Joint Infection in Malaysia.

Background and objectivePeriprosthetic joint infection (PJI) is one of the dreaded complications in patients after arthroplasty surgeries, owing to the risk of morbidity and arduous investigations and management associated with it. Nevertheless, as Malaysia is currently battling against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced coronavirus disease 2019 (COVID-19) pandemic head-on, the treatment for other non-life-threatening diseases including PJI has taken a backseat. In this study, we present a case series of 11 patients with PJI who were managed surgically at the largest tertiary hospital in Malaysia and we hope to shed some light on the difficulties we have encountered during this trying period.Patients and methodsPatients with PJIs who underwent surgical intervention during the ongoing COVID-19 pandemic (March 1, 2020, to June 30, 2021) were reviewed and included in this study. The demographic profile of the patients, presenting complaints, prosthesis topography, biochemical investigative findings, surgical interventions, and short-term outcomes were summarized.ResultsA total of 11 patients were treated surgically at Hospital Kuala Lumpur for PJI. Among them, five patients are still awaiting their second-stage surgeries despite the completion of their antibiotic regimes, and they are fit for the procedure.ConclusionThe COVID-19 pandemic has wreaked havoc on the treatment of patients with PJI. In a setting with scarce resources, surgeons should strongly consider single-stage revision surgeries for the treatment of patients with PJI.

Recurrent Aortobronchial Fistula after Endovascular Stenting for Infected Pseudoaneurysm of the Proximal Descending Thoracic Aorta: Case Report

Aortobronchial fistula (ABF) induced by an infected pseudoaneurysm of the thoracic aorta is a life-threatening condition. As surgical treatment is associated with significant mortality and morbidity, thoracic endovascular aneurysm repair (TEVAR) may be an alternative for the treatment of ABF. However, the long-term durability of this intervention is largely unknown and the recurrence of ABF is a potential complication. We experienced a case of recurrent ABF after stent grafting as an early procedure for an infected pseudoaneurysm of the thoracic aorta. Remnant ABF, bronchial and/or aortic wall erosion, vasa vasorum connected with ABF, and recurrent local inflammation of the thin aortic wall around ABF might cause recurrent hemoptysis. As a result, we suggest that TEVAR should be considered as a bridge therapy for the initial treatment of ABF resulting from an infected pseudoaneurysm, and that several options, such as second-stage surgery, should be considered to prevent the recurrence of ABF.

Allograft Bone Dowel Incorporation to Tibial and Femoral Tunnels in Two–Stage Revision Anterior Cruciate Ligament Reconstruction (173)

Objectives:The purpose of this study was to quantitatively evaluate the radiographic outcomes of allograft dowels used as bone grafts in two-stage revision anterior cruciate ligament reconstruction (ACLR).Methods:Prospective review of patients who underwent 2-stage revision ACLR with allograft bone dowels. Inclusion criteria were tibial/femoral tunnel diameter of >14 mm on pre-operative computed tomography (CT), overlapping prior tunnels with new tunnels (Figure 1). Allograft dowels were placed during the first stage and arthroscopic assessment of dowels was performed at the second-stage revision (Figure 2). Quantitative analysis of radiographic incorporation rates was performed with the Union Ratio (UR, Figure 3A) and Occupying Ratio (OR, Figure 3B) on post-operative CT scans. Biopsy specimens were obtained to analyze incorporation.Results:21 patients were included. Second-stage revision surgeries were performed at 6.5 months (SD, 2.1 months) after first-stage revision. All dowels preserved their integrity without any signs of degradation and complete incorporation at the host bone and graft junction at the second stage procedure. The average diameter of the dowels placed in tibial tunnels were greater than those placed in femoral tunnels (16.1 mm [SD, 2.3 mm] vs 12.4 mm [SD, 1.6 mm]; p = < .05). CT scans were obtained at 121 days (SD, 28 days) after the first-stage. There was no difference between the OR of femoral and tibial tunnels (87.6% [SD, 4.8%] vs 85.7% [SD, 10.1%]; p = .484), however, the UR was significantly higher in femoral tunnels (74% [SD, 10.5%] vs 83%[ SD, 6.2%], p = 0.005). Histological examination revealed osseous incorporation between the host bone and allograft dowel (Figure 4).Conclusions:Allograft bone dowels are a safe graft choice to replenish bone stock in the setting of a staged revision ACL reconstruction and dowels placed in femoral tunnels had a higher healing union ratio. Further studies are warranted to evaluate long-term clinical outcomes in this subset of patients.

Predictors for Implant Rupture in Two-Stage Tissue Expander-Based Breast Reconstruction: A Retrospective Cohort Study.

Two-stage tissue expander/implant-based method has been used predominantly for breast reconstruction. Implant rupture is one of the bothersome complications, inducing additional morbidity including reoperation. The present study aimed to identify the independent factors associated with development of implant rupture. Patients who underwent immediate two-stage prosthetic breast reconstruction between 2010 and 2016 were reviewed. Inserted implants were followed up using magnetic resonance imaging every 2 years and/or ultrasound/computed tomography scans every 6 or 12 months that were conducted for cancer surveillance. Associations of perioperative and intraoperative variables with the development of implant rupture were evaluated. In total, 797 cases (744 patients) were analyzed. During a median follow-up of 43months after second-stage operation, implant rupture was identified in 22 cases. The 5-year cumulative incidence was 3.1%. Multivariable analyses showed that the interval between the first- and second-stage operations was inversely associated with the risk of implant rupture. Maximal discrimination was observed at the interval of 6.5months. Cases with an interval ≤6 months were associated with higher risks for implant rupture than those with ≥7 months, after adjusting for other variables. Type of implant was associated with the development of implant rupture, showing that using two kinds of fourth-generation implant (Allergan Biocell textured round and Allergan smooth round implants) was associated with a significantly increased risk of implant rupture compared with that of Mentor MemoryShape implants (fifth-generation implant). Several operation-related variables appear to be associated with implant rupture in two-stage prosthetic reconstruction.

Reconstruction of Large Cervicofacial Defects With Expanded Island Superficial Temporal Artery Flaps and an 810-nm Diode Laser Hair Removal Technique.

Extensive cervicofacial reconstruction is challenging for plastic surgeons. Because of the location of the adjacent scalp flap nourished by the superficial temporal artery (STA), it can be a candidate for cervicofacial reconstruction. This article aims to report a combined treatment of an expanded island STA flap and an 810-nm diode laser hair removal technique for extensive cervicofacial defects. Between January 2015 and December 2018, 10 patients with lower face and neck scar contraction were reconstructed with a bilateral or unilateral expanded STA island flap and an 810-nm diode laser for hair removal in this retrospective study. Hair removal via the 810-nm laser was started when the injected volume reached the volume of the expander, with a fluence of 35 to 40 J/cm2 and a 1 to 2 Hz repetition rate. Before second-stage surgery, the hair reduction rate was assessed. Twelve months after surgery, the degree of epilation efficacy according to the satisfaction scale and Global Aesthetic Improvement Scale was evaluated. This study included 2 single-pedicle flaps and 8 double-pedicle flaps. The average size of the implanted expanders was 600 mL. The average injected volume was 1405 mL. Before second surgery, there was a 67.4% hair reduction rate. Twelve months after surgery, the results of Global Aesthetic Improvement Scale were very good (3), good (6), average (1), and poor (0). The expanded island STA flap and 810-nm diode laser technique may be a novel treatment option for severe face and neck aesthetic reconstruction.