Rainer Kubiak’s research while affiliated with University of Mannheim and other places

Objective The pyeloureteral anastomosis remains the most challenging part of pyeloplasty. A purpose-built anastomotic device could simplify this step and potentially improve outcomes. The concept of a pyeloureteral magnetic anastomosis device (PUMA) was proven in minipigs, but only in short term. Our aim was to test the PUMA in domestic pigs and achieve a prolonged follow-up period. Methods Five female domestic pigs underwent laparoscopy and ligation of the left ureter. Four weeks later, laparoscopic implantation of the PUMA was planned. Removal of the device and a retrograde contrast study were scheduled after another 4 weeks. The experiment was terminated when the animals could no longer be properly cared for due to their weight. Results Due to unexpected smaller ureteric diameters, a modified PUMA could only be successfully inserted in pig number 3 (49 kg). Four weeks later, the device was found to be dislocated, but the anastomosis remained patent. After modifying the study protocol, the PUMA was successfully implanted in pigs number 4 (96 kg) and 5 (68 kg) 8 weeks after ureteric ligation. Pig 4 developed malignant hyperthermia and died. In pig 5, the magnets were removed 4 weeks later. After an additional 8 weeks, the animal reached 135 kg and was terminated. The anastomosis remained patent and preserved its diameter. Conclusion Despite limitations, our study successfully demonstrated that the PUMA can achieve a patent ureteric anastomosis in domestic pigs. This suggests a potential for minimally invasive ureteric anastomosis in clinical settings. Further research is needed to optimize the technique and validate its effectiveness in humans.

Simulation-based training (SBT) has a significant role in training in complex procedure like laparoscopic pyeloplasty. We propose a new training model for laparoscopic pyeloplasty which has been compared to other models. Trainees (n = 22) evaluated our balloon model (BM) and three other models -glove finger model (GFM), chicken thigh model (ChTM) and chicken crop model (ChCrM)- subjectively, based on a 5-point Likert scale. The face validity mean score of our BM model was 3.58 ± 0.69. Our novel model can be a cost-effective, hygienic, and easy-access alternative to other laparoscopic pyeloplasty models.

Background We designed a new Esophageal Magnetic Anastomosis Device (EMAD) for thoracoscopic repair of esophageal atresia (EA) with tracheoesophageal fistula (TEF) without the need of handheld suturing or additional gastrostomy. Methods Synthetic EA-TEF model: Spherical and tubular shaped rubber balloons and a term infant sized plastic doll were used. Medical students (n=10) and surgical trainees (n=10) were asked to perform thoracoscopic repair of an „EA” with a hand sutured anastomosis (HA) and with the EMAD. Euthanized animal model: The esophagus in 5 piglets (3-4 kg) was dissected and a thoracoscopic esophageal magnetic anastomosis (EMA) was performed. Bursting pressure (BP) and pulling force (PF): HA and EMA were created on ex vivo New Zealand white rabbit (2.5-3 kg) esophagi (n=25 in each test series). BP and PF were measured and compared against each other. Results Medical students were unable to complete HA, but were successful with the EMAD in 11.1±2.78 min. Surgical trainees completed EMA in 4.6±2.06 min vs. HA 30.8±4.29 min (p<0.001). The BP following a HA (14.1±3.32 cmH2O) was close to the physiological intraluminal pressure reported in a neonatal esophagus (around 20 cmH2O), whereas the BP with the EMAD was extremely high (>90 cmH2O) (p<0.001). The PF of an EMA (1.8±0.30 N) was closer to the safety limits of anastomotic tension reported in the literature (i.e. 0.75 N) compared with the HA (3.6±0.43 N) (p<0.0001). Conclusion The EMAD could simplify, shorten, and potentially improve the outcome of thoracoscopic repair for EA with TEF in the future. A high BS and a relative low PF following EMAD application may lower the risk of postoperative complications such as esophageal leakage and stricture formation.

Introduction: The aim of this study was to compare the long-term outcomes of laparoscopic complete (Nissen) fundoplication (LNF) with laparoscopic partial (Thal) fundoplication (LTF) in children. This is the only prospective, randomized study to follow patients up for more than 10 years. Interim results published in 2011 at median 2.5 year follow-up showed that LNF had a significantly lower failure rate compared with LTF. Materials and Methods: A randomized, controlled trial of LNF versus LTF in children (<16 years) was performed. The primary outcome measure was "absolute" failure of the fundoplication-recurrence of symptoms that merited either reoperation or insertion of transgastric jejunostomy (GJ). Secondary outcomes were "relative" failure (need for postop antireflux medication), complications (e.g., dysphagia), and death. Results: One hundred seventy-five patients were recruited; 89 underwent LNF, and 86 underwent LTF. Eight patients had no follow-up recorded. At long-term follow-up, 59 patients had died (35%); LNF 37/85 (43.5%) and LTF 22/82 (26.8%), P = .02. Median length of follow-up in survivors was 132 months. There was no statistically significant difference in "absolute" failure rate between LNF 8/85(9.4%) and LTF 15/82 (18%), P = .14. There was no difference in "relative" failure between LNF 7/85 (8.2%) and LTF 12/82 (14%), P = .23. Long-term dysphagia affected 5 out of 108 (4.6%) patients; 3/48 (6.2%) of LNF and 2/60 (3.3%) of LTF (P = .65). Conclusions: There was no statistically significant difference in 'absolute' failure between LNF and LTF at long-term follow-up. Neurologically impaired children have a high mortality rate following fundoplication due to comorbidities. This trial commenced in 1998 and was approved by the Oxfordshire Research Ethics Committee (No. 04.OXA.18-1998).

Laparoscopic pyeloplasty (LP) is a standard, but demanding operation. According to the European Association of Urology guidelines this procedure scores 13 out of 18 on the difficulty scale [1]. Articulating instruments, 3D video systems and robots may facilitate complex suturing of the ureteropelvic anastomosis at higher costs [2,3]. Magnetic compression anastomosis (magnamosis) has been used safely and effectively in the gastrointestinal tract [4,5], however not been applied in the urinary tract.

Background There is a lack of experience with fully covered self-expandable metal stents (SEMSs) for the treatment of esophageal leakage particularly in infants and neonates. Methods Eight patients (5M, 3F) with a median age of 17 months (range, 1–135 months) who underwent treatment with SEMSs for an anastomotic leakage or perforation of the esophagus were recruited to this retrospective study. Four children were born premature. In six patients the stents were placed primarily as an emergency procedure. Results Median duration of individual stent placement was 42 days (range, 13–72 days). Six out of eight patients (75%) were treated with one stent only. In three preterm infants who had their stents inserted within the first month relative weight gain was 17% compared with 2% in five patients who were treated later in life (p=0.0986). In four cases (50%) distal migration of the stent was observed. Seven out of eight patients (88%) had their leakage resolved after stent therapy. Conclusions Insertion of fully covered SEMSs is an alternative tool for the treatment of esophageal leakage in children and preterm infants, and successful with only one single application in selected cases. It can be used either following previous therapy or as part of an emergency procedure. Because of the absence of manufactured, age-related devices SEMSs that are originally designed for other organs can be applied.

To review our institutional results and assess different surgical and non-surgical techniques for the treatment of displaced diametaphyseal forearm fractures in children and adolescents. Thirty-four children (25M, 9F) with a total of 36 diametaphyseal forearm fractures who underwent treatment under general anesthesia between July 2010 and February 2016 were recruited to this retrospective study. From October 2016 until March 2018 patients and/or parents were contacted by telephone and interviewed using a modified Pediatric Outcomes Data Collection Instrument (PODCI). Median age at the time of injury was 9.1 years (range, 1.9–14.6 years). Initial treatment included manipulation under anesthesia (MUA) and application of plaster of Paris (POP) (n = 9), elastic stable intramedullary nailing (ESIN) (n = 10), percutaneous insertion of at least one Kirschner wire (K-wire) (n = 16), and application of external fixation (n = 1). Eleven children (32%) experienced a total of 22 complications. Seven complications were considered as major, including delayed union (n = 1) and extensor pollicis longus (EPL) tendon injury (n = 1) following ESIN, as well as loss of reduction (n = 2) and refractures (n = 3) after MUA/POP. The median follow-up time was 28.8 months (range, 5.3–85.8 months). In 32 out of 34 cases (94%) patients and/or parents were contacted by telephone and a PODCI score was obtained. Patients who experienced complications in the course of treatment had a significantly lower score compared with those whose fracture healed without any sequelae (P = .001). There was a trend towards an unfavorable outcome following ESIN compared with K-wire fixation (P = .063), but not compared with POP (P = .553). No statistical significance was observed between children who were treated initially with a POP and those who had K-wire fixation (P = .216). There is no standard treatment for displaced pediatric diametaphyseal forearm fractures. Management with MUA/POP only is associated with an increased refracture rate. Based on our experience K-wire fixation including intramedullar positioning of at least one pin seems to be favorable compared with ESIN.

Purpose: There is a lack of experience with stenting for benign pancreaticobiliary disorders in children. Materials and Methods: Fifteen children (9 male and 6 female) with a median age of 7.1 years (range 0.7-14.2 years) who underwent treatment with a plastic stent for a benign disorder of the pancreaticobiliary system between May 2003 and September 2017 were recruited to this retrospective study. Results: Biliary and/or pancreatic plastic stents were inserted into 5 patients with congenital, 4 with post-traumatic, and 6 with idiopathic pathologies. Median duration of individual stent placement was 111 days (range 14-1569 days). Eleven children (73%) were treated with one stent only. In 4 cases, up to 22 stents were successively placed over time. There were no complications during stent insertion or stent removal. Seven patients (47%) experienced adverse effects during stenting, including choledocholithiasis, pancreaticolithiasis, cholangitis, acute pancreatitis, stent obstruction, and stent fracture. At follow-up, in 11 cases (73%), the underlying condition was resolved. In 4 children, all of whom suffered from congenital pancreaticobiliary disorders, stent therapy was considered as a temporary treatment before definite surgery. Conclusions: Patients with congenital anomalies of the pancreaticobiliary tree often require surgery for definitive management. However, temporary stent placement can be accomplished safely and successfully and this serves as a bridge to temporize their obstructive process while awaiting surgical intervention. Children with post-traumatic or idiopathic disorders can frequently be managed definitively by stenting alone and many of these require only one single stent insertion.

There is a lack of experience with fully covered self-expandable metal stents (SEMSs) for the treatment of benign esophageal conditions in the pediatric population. This is the evaluation of our institutional experience of placing SEMSs for anastomotic stricture (AS) formation following esophageal atresia (EA) repair. Patients were jointly managed from the Department of Pediatric Surgery and Central Interdisciplinary Endoscopy at our institution. Thirteen children (8 male, 5 female) with a median age of 4 months (range: 1–32 months) who underwent treatment with SEMSs for a postoperative AS following EA repair between February 2006 and April 2016 were recruited into this retrospective study. SEMSs that are originally designed for other organs such as trachea, bronchus, biliary tract, or colon were inserted under general anesthesia via endoscopic guidance. Simultaneous fluoroscopy was not required in any case. In five infants, the stents were inserted primarily without previous therapy. Seven patients underwent stenting following dilatation with or without adjuncts (e.g. Mitomycin C, Triamcinolone). In one case with an AS and a simultaneous persistent tracheoesophageal fistula (TEF), multiple SEMSs were applied after failure to close the fistula with fibrin glue. The median duration of individual stent placement was 30 days (range: 5–91 days). In five children up to four different biliary, bronchial or colonic SEMSs were placed successively over time. There were no problems noted at stent insertion or removal. Eight children (62%) developed complications associated with stenting. At follow-up, in eight patients (62%) AS was resolved, including all of those five cases, who had their stents inserted without previous therapy. Five children (38%), who underwent dilatation prior to stenting did not improve their AS and required further intervention. Overall, the cohort exhibited a slight, but not significant weight gain between stent insertion and (final) stent removal. Insertion of SEMSs for AS following EA repair is safe and often successful with only one single application. It can be used as a primary procedure (without previous therapy) or after failed dilatations. There was one death in this study that was unrelated to stenting and occurred 12 months after stent removal. Because of the absence of manufactured, age-related devices, SEMSs that are originally designed for other organs can be applied. Establishment of a standardized management including stent placement for the treatment of AS following EA repair in the pediatric population is required.

Background: Thermal injuries are one of the most physically and psychologically devastating causes of pediatric trauma. Post-traumatic sequelae such as hypertrophic scars and contractures often result in long lasting morbidity and disfigurement. Conservative therapy, including pressure garments and silicone, is the gold standard for scar management in the pediatric population. Most recently percutaneous collagen induction (PCI) was introduced as an alternative treatment in adults. The aim of this report was to share our experience with PCI in children and adolescents in scar management following thermal injuries. Patients and methods: Between July 2013 and February 2016, a total of 99 PCI treatments were performed on forty-seven children and adolescents for scar formation following thermal injuries in this retrospective study. A medical roller device (Dermaroller(®), Dermaroller GmbH, Wolfenbüttel, Germany) with 2.5mm long needles was used. All procedures were carried out under general anesthesia. At the end of the operation vitamin A and vitamin C oil (ENVIRON(®) AVST Body Oil; Environ Skin Care, Pty. Ltd., Cape Town, South Africa) was applied topically. Photographs were taken before and a minimum of 4 weeks after the first PCI in order to document the effect on scar tissue. These images were graded according to the Vancouver Scar Scale (VSS). Results: The median age at the time of the first PCI was 8.3 years (range, 0.8-21.2 years). The median time interval between the injury and PCI was 18 months (range, 4-170 months). There were no intraoperative problems noted. Minor postoperative complications occurred in 2 patients (4.3%). All patients reported subjective improvement and were satisfied with the procedure and the results. Pre- and post-treatment photographs were available in 40 patients, and overall VSS scores improved post-treatment in all patients. Following a single PCI treatment, scar vascularity, pliability and height all improved, however there was no statistically significant effect on pigmentation. Conclusions: PCI is an enrichment of the armamentarium for scar treatment following thermal injuries in children and adolescents. Further prospective studies are recommended regarding the optimal timing for this treatment and long term outcome in the pediatric population.