Andreas Lindner’s research while affiliated with Johannes Gutenberg University Mainz and other places

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Publications (21)


Iterative Design and Manufacturing of a 3D-Printed Pediatric Open and Laparoscopic Integrated Simulator for Hernia Repair (POLISHeR)
  • Article

February 2025

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5 Reads

Journal of Pediatric Surgery

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Eric Greaney

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Julia Hael

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[...]

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Estimated marginal means of the repeated‐measures analysis of variance are seen here for weight gains. Error bars represent 95% confidence intervals for the estimated marginal means within the groups of different resection lengths. All piglets that reached the endpoint (n = 23) were included in the analysis. Weight gain appears less steep for longer resection lengths, but the differences were not statistically significant.
Representative macroscopic depiction of an explanted sham esophagus (A) and of the esophageal stricture following 5 cm esophageal resection and re‐anastomosis (B). The stricture is marked by the arrow.
Postoperative stricture after esophagotomy and 5 cm segmental resection with reanastomosis (arrow). Although the contrast study passes distally into the stomach readily, explaining continuous postoperative weight gain, the stricture is well delineated and morphologically resembles strictures seen clinically after esophageal atresia repair.
No stricture is seen in the sham group.
Subjectively, stricture severity seemed to increase with longer resection lengths on contrast radiography.
A novel piglet model of esophageal stricture following variable segmental esophageal resection and re‐anastomosis
  • Article
  • Full-text available

November 2024

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38 Reads

Background Esophageal strictures following esophageal atresia repair are a source of significant morbidity. To test new therapeutic approaches, we designed a piglet model of esophageal stricture by resecting variable lengths of esophagus with subsequent re‐anastomosis. This study describes the model and validates its physiologic impact by blinded analysis of the weight gains of the piglets. Methods A total of 24 two‐week old Pietrain piglets had esophageal resections performed, ranging from 0 to 5 cm, with the goal of inducing postoperative esophageal strictures. Postoperative body‐weights were evaluated by repeated analysis of variance followed by pairwise group‐comparisons based on estimated marginal means. In addition, body weight was modeled by linear‐mixed model regression. Different resection lengths were compared. The esophagi were evaluated postmortem for stricture. Results Of 24 operated piglets, 23 reached the endpoint, and 90% developed an esophageal stricture that was radiologically visible in a contrast study, as well as appreciable macroscopically in the necropsy. We found differences in pre‐ and postoperative body weights for all piglets (F (1, 18) = 298.54, p < 0.001), but no differences between resection lengths (F (4, 18) = 0.36, p = 0.837). Conclusion Our model of postoperative esophageal stricture offers the opportunity to investigate potential treatments for strictures associated with esophageal atresia, since it reliably induces strictures and results in minimal loss of animals. The similar body weight gain in all groups indicates that stricture is mainly the result of esophageal resection and re‐anastomosis, regardless of the length of the resected segment.

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SuSiPed: An initial step towards a universal, low-cost, 3D-printable platform for pediatric minimal-invasive surgery training

December 2022

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29 Reads

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3 Citations

Journal of Pediatric Surgery

Background: Training platforms such as the Fundamentals of Laparoscopic Surgery have become an integral part of postgraduate adult general surgical education. So far, however, there is no such universal tool for pediatric minimal-invasive surgery (MIS). We therefore designed and validated a novel 3D printable pediatric MIS simulation program. Methods: The SuSiPed (Surgical Simulation in Pediatrics) curriculum consists of 6 MIS training modules: camera guidance, shell transfer, figure cutting, cyst resection, single interrupted suturing, and slipknot suturing. All modules can be 3D printed, and thus manufactured in a low-cost, sustainable and reproducible fashion. Instructional videos for the participants for each module were created. For validation, a group of medical students and surgical residents were compared to a group of pediatric surgical specialists with experience in MIS. All participants performed the entire SuSiPed curriculum 3 times, measuring time to task completion and technical mistakes. The results of the last attempt were compared using Welch's T-test. Results: There were 25 participants in the novice group and 5 in expert group. Times to task completion were lower in the expert group for all modules except camera guidance. Errors were significantly more frequent during slipknot suturing in the novice group, while there were no difference in the other modules. Conclusion: Our novel training platform showed good construct validity for 5 out of 6 modules, while scores of camera navigation was not associated with prior experience. The SuSiPed platform is useful for pediatric minimal-invasive surgery training and evaluation, even in low-resource countries where expensive simulators are not affordable. Level of evidence: Level III, Validation Study.


Novel Device for Endoluminal Esophageal Atresia Repair: First-in-Human Experience

October 2021

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103 Reads

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24 Citations

Pediatrics

Thoracoscopic esophageal atresia (EA) repair affords many benefits to the patient; however, intracorporeal suturing of the anastomosis is technically challenging. Esophageal magnetic compression anastomosis (EMCA) is a compelling option for endoluminal EA repair, but available EMCA devices have prohibitive rates of recalcitrant stricture. Connect-EA is a new endoluminal EMCA device system that employs 2 magnetic anchors with a unique mating geometry designed to reliably create a robust anastomosis and decrease rates of leak and stricture. We describe our first-in-human experience with this novel endoluminal device for staged EA repair in 3 patients (Gross type A, B, and C) at high risk for conventional surgical repair. First, the esophageal pouches were approximated thoracoscopically. After acute tension subsided, the device anchors were endoscopically placed in the esophageal pouches and mated. Anchors were spontaneously excreted in 2 cases. Endoscopic repositioning and retrieval of the anchors were required in 1 patient because of narrowed esophageal anatomy. There were no perioperative complications. Patients were managed for 14 to 18 months. The strictures that developed in the patients were membranous and responded well to dilation alone, resolving after 4 to 5 outpatient dilations. Gastrostomies were closed between 6 and 11 months and all patients are tolerating full oral nutrition. Early experience with this new endoluminal EMCA device system is highly favorable. The device offers considerable benefit over conventional handsewn esophageal anastomosis and anastomotic outcomes are superior to available EMCA devices.


An experimental study on long term outcomes after magnetic esophageal compression anastomosis in piglets

September 2021

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33 Reads

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18 Citations

Journal of Pediatric Surgery

Background/Purpose Previous studies have shown that a patent, watertight esophageal anastomosis can be accomplished safely using specially-shaped magnets in piglets. However, it is unclear whether such a magnetic esophageal compression anastomosis (MECA) remains patent in the long-term. The purpose of this study was to evaluate the long-term outcome of MECA in an experimental pig model over an observation period of 2 months. Methods Ten piglets underwent creation of an MECA with custom-made 8mm magnets and a U-shaped esophageal bypass loop to allow peroral nutrition at eight weeks of life. Two weeks later, the bypass loop was closed surgically, requiring the pigs to swallow via the newly created magnetic compression anastomosis. The pigs were fed soft chow for 2 months. They were monitored for weight gain and signs of dysphagia. At the endpoint of two months, esophagoscopy and contrast esophagography was performed. After removal of the esophagus, the tissues were macroscopiocally and histologically assessed. Results Six piglets survived until the endpoint. In two pigs, closure of the bypass loop failed, these demonstrated mean weight gain of 792 grams/day [95% Confidence interval 575 to 1009 grams/day]. Weight gain in four pigs that exclusively fed via the magnetic anastomosis averaged 577 grams/day [95% confidence interval 434 to 719 grams/day (p=0.18)]. There were no signs of dysphagia. All magnets passed with the stool within 16 days. After 2 months, a well-formed magnetic compression anastomosis was visible and easily negotiated with a 6.5mm endoscope. Esophogram and macroscopic findings confirmed patentency of the esophageal anastomoses. Histopathology showed a circular anastomosis lined with contiguous epithelium. Conclusion MECA creates a long-term functional and patent anastomosis in pigs. This concept may facilitate minimally-invasive esophageal atresia repair by obviating a technically challenging and time-consuming hand-sewn anastomosis.


Laparoscopic Duodenal Atresia Repair

August 2021

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15 Reads

Laparoscopic duodenal atresia repair is an alternative to the open technique that requires expertise in intracororeal suturing and knot-tying. Although the operative times are generally longer than with the open technique, the complication rates and outcomes are similar, but without leaving the typical upper quadrant transverse scar.


Comparing Aachen Minipigs and Pietrain Piglets as Models of Experimental Pediatric Urology to Human Reference Data

November 2020

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86 Reads

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5 Citations

European Surgical Research

Introduction: Swine had special roles in the development of minimally invasive procedures to treat vesicoureteral reflux, and minipigs have been gaining ground in recent years in experimental pediatric urology as they combine small size with less vulnerable adult physiology, but their suitability as a model has never been assessed. We therefore compared a landrace piglet with a juvenile minipig to elucidate comparability. Methods: We evaluated five 3-week old Pietrain piglets and five 3-month old Aachen Minipigs as representatives of landrace and minipig models based on their expected bodyweight being similar to a newborn human. We compared renal weight, volume - via the ellipsoid formula - and ureteral length. In addition, we calculated porcine renal function via Gasthuys' formula. In order to compare the groups with previously published values for infants, we used resampling techniques to allow comparison to humans. Results: Renal weight was higher in humans than in Pietrain piglets (ΔL = 7.6 g; ΔR = 5.4 g) and Aachen Minipigs (ΔL = 11 g; ΔR = 9.4 g). Renal volumes in humans were higher than in both Pietrain piglets (ΔL = 5.6 mL, p < 0.001; ΔR = 3.7 mL, p = 0.004) and Aachen Minipigs (ΔL = 8.1 mL; ΔR = 6.6 mL; both p < 0.001). Ureteral lengths in humans and both pig breeds were comparable as were estimated renal functions between both pig breeds. Discussion and conclusion: Both landrace piglets and juvenile minipigs are suitable models for experimental pediatric urology as parameters did not differ between them. In addition, the anatomic parameters are comparable or smaller than in infants. This might facilitate translational research as technical failure is less likely in larger organs. Additional research is necessary to cover higher age ranges than those included in the present pilot study.


Citations (14)


... Simulators were utilized across various specialties such as general surgery [6][7][8][9][10][11][12][13][14][15][16][17] (OSIR , emergency and trauma [18], neurosurgery [3,4,8,[19][20][21][22][23][24][25][26][27][28] (OSIR 27-31), orthopedics [29] (OSIR 32, 33), gynecology [30] (OSIR 34,35), otolaryngology [1,[31][32][33][34][35] (OSIR [36][37][38], ophthalmology [36], cardiothoracic [37], pediatric [38][39][40][41] (OSIR 39,40), urology [42,43] (OSIR 41,42), dental (OSIR 43), and gastroenterology [44] ( OSIR 44,45). A list of simulators for various procedures in different specialties is provided in Table 2. ...

Reference:

Low-Cost Endoscopic Surgical Skill Simulation Training: A Systematic Review
SuSiPed: An initial step towards a universal, low-cost, 3D-printable platform for pediatric minimal-invasive surgery training
  • Citing Article
  • December 2022

Journal of Pediatric Surgery

... A significant proportion of children develop musculoskeletal deformities after thoracotomy, but most of them are subclinical. An axillary muscle-sparing technique has been shown to significantly decrease the incidence of these deformities [6][7][8][9][10]. Other complications (leakage, dehiscence, stenosis…) are not directly related to the surgical approach, but are influenced by factors such as the type of EA, patient characteristics and technical details. ...

Novel Device for Endoluminal Esophageal Atresia Repair: First-in-Human Experience
  • Citing Article
  • October 2021

Pediatrics

... Since Obora reported the study of microvascular magnetic anastomosis in 1978, magnetic compression anastomosis (MCA) has attracted the attention of clinicians. The research on MCA and its clinical application in gastroenterology comprises esophageal [1][2][3], gastrointestinal [4][5][6], and small bowel [7][8][9] anastomosis. Other examples include vascular[10-11] and ureterovesical [12] anastomosis. ...

An experimental study on long term outcomes after magnetic esophageal compression anastomosis in piglets
  • Citing Article
  • September 2021

Journal of Pediatric Surgery

... The Minipig offers the advantage of a more robust physiology due to their more advanced age at similar body weights to the human patient,12,22,46 facilitating their perioperative care. ...

Comparing Aachen Minipigs and Pietrain Piglets as Models of Experimental Pediatric Urology to Human Reference Data

European Surgical Research

... Diagnoses and procedures were compared between sexes with the Mann-Whitney-Wilcoxon U-test. As regular confidence intervals require a normal distribution of data, bias-corrected accelerated bootstrap confidence intervals with 10,000 repetitions [24,25] have been calculated using the smean.cl.boot-function from the Hmisc-package (version 4.4-0) [26,27] for point estimates and for mean differences by bootstrapping the mean differences using the two.boot-function from the simpleboot-package (version 1.1-7) [28] to supply it to the boot.ci-function ...

Tracheal bifurcation located at proximal third of oesophageal length in Sprague Dawley rats of all ages

Scandinavian Journal of Laboratory Animal Science

... We feel that transparency is crucial within the scientific discourse [3][4][5][6], and we agree that the search strategy should be readily available. The list of included meta-analyses and the extracted data [7] have been put into a repository and cited in reference 35 of our initial contribution, so that the readership is able to double-check and reproduce our results. ...

Sex represents a relevant interaction in Sprague–Dawley rats: the example of oesophageal length*

... Traction forces were gauged using a tensiometer (FL100, Kern & Sohn, Balingen, Germany) until the muscular layer was disrupted and the mucosal layer was still visible. This was registered as a loss of force by the tensiometer and the maximum value was recorded as the breaking force [50][51][52][53][54][55]. The experimental setup has been described in detail elsewhere [53,54] and is photographically depicted in Figure 2. We conducted all experiments within two hours after the swine's euthanasia to ensure that our results were not affected by structural changes due to cell death. ...

A Continuous Suture Anastomosis Outperforms a Simple Interrupted Suture Anastomosis in Esophageal Elongation

European Journal of Pediatric Surgery

... We obtained 24 freshly weaned, two-week-old Pietrain piglets of both sexes (7 ♂; 17 ♀) from a local organic farmer licensed to sell swine for biomedical research as described before. 22 Individual pigs were randomized to one of five experimental groups (sham operation, as well as thoracotomy with resection of 9, 1, 3, and 5 cm of esophagus with subsequent anastomosis) based on pre-defined random numbers from a random number generator. 23 To reduce possible bias by simple randomization, the experiments were conducted as two separate experiments 24 with starting days 6 weeks apart. ...

Using multidimensional scaling in model choice for congenital oesophageal atresia: similarity analysis of human autopsy organ weights with those from a comparative assessment of Aachen Minipig and Pietrain piglets

Laboratory Animals

... Magnetic compression anastomosis (MCA) is a novel technique for the anastomosis of cavity organs through "noncontact" magnetic force. The current basic and clinical studies on MCA cover esophageal anastomosis [7][8][9], gastrointestinal anastomosis [10,11], and colorectal anastomosis [12,13] of the digestive system. MCA can be used for vascular anastomosis [14][15][16] and therapeutic ostomy [17][18][19] for non-gastrointestinal conditions. ...

An Experimental Study on Magnetic esophageal compression Anastomosis in Piglets
  • Citing Article
  • May 2019

Journal of Pediatric Surgery

... The biomechanical properties of organs have long been of interest for surgical procedures in particular [1][2][3][4][5]. With the ongoing progress in interventional gastroenterology, regularly replacing surgery [6][7][8][9], the biomechanical properties of intestinal organs recently came into focus, too [10]. ...

Using simple interrupted suture anastomoses may impair translatability of experimental rodent oesophageal surgery

Acta Chirurgica Belgica