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ORIGINAL ARTICLE Table of Contents   
Year : 2009  |  Volume : 6  |  Issue : 2  |  Page : 73-76
GABBY: An ex vivo model for learning and refining the technique of preformed silo application in the management of gastroschisis

Department of Paediatric Surgery, King's Hospital, Denmark Hill, London, United Kingdom

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Date of Web Publication29-Jul-2009


Background: Gastroschisis (GS) is a congenital full-thickness defect of the anterior abdominal wall, whose incidence is increasing. Traditional postnatal management options include primary reduction and closure under general anaesthetic or operative silo construction for defects judged to be unsuitable for immediate repair. The cot-side application of the preformed silo (PFS) with delayed abdominal wall closure has recently been advocated as the management method of choice for infants with GS. We report a novel trainer designed to facilitate acquisition and refinement of the skills to apply the PFS. Materials and Methods: A model of an infant with GS was constructed to allow application of a PFS. Each step of the clinical application of a PFS could be simulated. Paediatric surgeons at a regional meeting participated in evaluating the model. This cohort was surveyed with regards to previous clinical experience applying the PFS, invited to apply the silo on the model and then resurveyed with regard to the technique, ease of the application of the PFS on the model, its robustness and potential use as a training tool. Results: Seventeen paediatric surgeons completed the surveys and applications of the PFS on the model. Under supervision, each step of the procedure was completed by all participants. Feedback was enthusiastic and positive and participants judged the model to be realistic and potentially very useful as a training tool (median score 8 out of 10). Conclusions: We have developed and evaluated a reproducible, low-cost model of an infant with GS. This ex vivo trainer may be a useful adjunct in the acquisition and refinement of the skills of surgeons who manage GS using a PFS.

Keywords: Ex vivo training, gastroschisis, preformed silo

How to cite this article:
Dabbas N, Muktar Z, Ade-Ajayi N. GABBY: An ex vivo model for learning and refining the technique of preformed silo application in the management of gastroschisis. Afr J Paediatr Surg 2009;6:73-6

How to cite this URL:
Dabbas N, Muktar Z, Ade-Ajayi N. GABBY: An ex vivo model for learning and refining the technique of preformed silo application in the management of gastroschisis. Afr J Paediatr Surg [serial online] 2009 [cited 2022 Sep 25];6:73-6. Available from:

   Introduction Top

Gastroschisis (GS) is a congenital full-thickness defect of the anterior abdominal wall, whose incidence is increasing, [1],[2],[3],[4] and may be as high as 4.4 per 10,000 live births. [5] Improvements in management have resulted in a substantial fall in mortality (6). Important factors in increased survival include better neonatal intensive care strategies and the widespread availability of parenteral nutrition. [6] The use of silos constructed from prosthetic materials is also thought to have been a significant contributor. [7]

Traditional postnatal management options include primary reduction and closure under general anaesthetic [8] or operative silo construction for defects judged to be unsuitable for immediate repair. [9] In 1998, Bianchi and Dickson [10] introduced the technique of cot-side reduction and closure without sedation or anaesthetic, but this has not found widespread acceptance. [11] Recently, the cot-side application of the preformed silo (PFS) has been advocated as the method of choice in infants with GS. [12] Several centres have reported encouraging outcomes, with putative benefits including a single delayed operative procedure, reduction of out-of-hours operating and improved physiological parameters. [6],[13],[14] However, some surgeons express concern about the potential technical difficulties of inserting the PFS in the awake infant.

The use of ex vivo trainers to enhance competence is now well established for both generic surgical skills [15],[16] and specific procedures. [17],[18] We report a novel trainer designed to facilitate acquisition and refinement of the skills to apply the PFS in the management of GS.

   Materials and Methods Top

A GS baby model (GABBY) was constructed using a commercially available toy doll (15" baby girl: You and Me , product ref 97227/515164). A circular defect 3cm in diameter was excised from the anterior abdominal wall to the right of the umbilicus. The eviscerated bowel was simulated using bovine sausage, lubricated and partially placed within the abdominal wall defect. The volume of the eviscerated abdominal contents was standardized by length (50 cm, 70 cm and 90 cm).

GABBY was evaluated at a regional academic meeting of paediatric surgeons (March 2007, Institute of Child Health, London). Consultant and trainee surgeons were recruited into the study. Each was asked to complete a survey detailing their experience with the PFS and invited to apply one, under supervision, as they would on a live infant. This involved assessment of the defect and bowel volume, choice and then application of an appropriate-sized PFS (3.0-6.0 cm silicone silo; Medicina Ltd., Bolton, UK). Feedback was provided by participants completing a second questionnaire. This included questions regarding technical aspects of the use of GABBY and potential usefulness as a training tool. Responses were provided on a scale of 1-10, where 1 was unhelpful/unrealistic and 10 was very helpful/realistic. Data are presented as median with ranges.

   Results Top

Seventeen respondents applied the PFS on GABBY and completed pre- and postapplication surveys. These included five consultants (29.4%), 10 middle grade trainees (58.8%) and two junior trainees (11.8%). Under supervision, each participant successfully completed the following steps: An assessment of the eviscerated bowel and abdominal wall defect followed by choice of an appropriately-sized silo to fit the size of the defect and accommodate the bowel volume. A gentle finger sweep at the level of the defect to confirm that there was no mechanical impediment to smooth application and then insertion of the bowel into the silo with care to place the apex loop first and prevent rotational distortion (the position of the wings were noted) was performed. The circular spring-loaded base of the silo was then compressed into an oval and one edge of it was inserted first into the abdominal wall defect followed by the remainder of the base in sequence. Once the entire base of the silo was inserted into the defect, the springing of the base and the effect of this stabilizing the silo and the bowel were noted. The wings of the PFS were positioned at the 6 and 12 o'clock positions to avoid the position of the umbilical cord at 3 o'clock. Care was taken again to ensure that there was no rotational distortion of the bowel loops. The empty apical portion of the silo was then tied off using a sialastic sling [Figure 1],[Figure 2],[Figure 3],[Figure 4],[Figure 5].

Feedback was enthusiastic and positive and participants judged the model to be realistic and potentially very useful as a training tool [Figure 6] [median score 8 out of 10 (range 5-10), where 10 was very realistic/potentially very useful as a training tool].

   Discussion Top

A study from Bristol in 1998 raised concerns regarding the rising incidence in the southwest of England. It demonstrated an increased incidence from 1.6 to 4.4/10,000 in the period 1987-1995. [19] This trend has been confirmed in other regions of the UK, prompting the chief medical officer to identify GS as "a growing concern" in his 2004 annual report. Upward trends have been demonstrated in several countries including Japan [20] and Norway. [4] In Utah, the incidence has increased 10-fold over three decades. [1] There are strategic implications for health care providers with regard to resource utilization and service delivery related to increases of this degree.

Some aspects of the management of GS remain contentious; in particular, the use of a silo and delayed abdominal closure versus primary surgical closure on day 1 of life.

In 1975, Shermeta and Haller [12] introduced the principle behind the PFS to protect eviscerated bowel while allowing time and pressure to produce gradual expansion of the abdominal cavity. The turn of the century has seen the use of modified versions of the PFS in several centres. A number of reports appear to validate putative benefits, including cot-side placement without anaesthesia, reduced ventilation time and reduction in the incidence of compartment syndrome. [13],[20],[21] The immediate coverage of exposed viscera and gradual reduction into the abdominal cavity may reduce the risk of homodynamic and respiratory compromise associated with primary closure of large defects, [14],[22],[23],[24] although not all users report positive results. [25] Specifically, there have been concerns regarding the risk of intestinal ischaemia related to the use of the PFS.

We have been using the PFS in our unit since 2004 and recently compared 13 infants managed with a PFS and delayed closure with 40 who underwent traditional closure. [26] The group managed with the PFS was associated with a reduction in barotrauma, better tissue perfusion and better early renal function. These findings are consistent with a reduction in abdominal compartment syndrome and, along with others, [27] we expect trends to favour this method of managing GS. Based on our experience, we recognize that while application of a PFS is a simple technique when mastered, at the outset, cot-side insertion is challenging to learn in the live, nonventillated infant. The use of an ex vivo model allows each step of the technique to be learned and refined.

Respondents who went on to choose and apply the PFS on GABBY did so with considerable enthusiasm, as reflected in the high scores regarding potential usefulness and authenticity of the model. Reservations were expressed by two vegetarians about bovine sausage. In the short term, this is easily rectified by the use of vegetarian sausage where required.

Experience extrapolated from laparoscopic surgery suggests that ex vivo training may be a valuable tool during the introduction of novel techniques to departments and individuals, helping to reduce the duration of the learning curve and the risk of adverse clinical consequences. [28] Some surgeons may accept the principles of gradual reduction, yet be dissuaded from using the PFS as a result of lack of hands-on experience. In this subset of potential users, GABBY could help build confidence in the technique, support practice and facilitate the training of junior surgeons. If the model is to be used regularly within a unit, there is the current drawback of having to obtain fresh material from the butcher each time the model is required. We are currently exploring the possibility of an appropriate synthetic replacement.

We have successfully evaluated a simple and reproducible model suitable for the ex vivo insertion of a PFS. Given the increased incidence of GS worldwide and the increasing use of the PFS with delayed abdominal wall closure, GABBY could become an important training tool in the management of this condition.

   References Top

1.Hougland KT, Hanna AM, Meyers R, Null D. Increasing prevalence of gastroschisis in Utah. J Pediatr Surg 2005;40:535-40.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]
2.Arnold M. Is the incidence of gastroschisis rising in South Africa in accordance with international trends? A retrospective analysis at Pretoria Academic and kalafong Hospitals, 1981-2001. S Afr J Surg 2004;42:86-8.  Back to cited text no. 2    
3.Tan KH, Kilby MD, Whittle MJ, Beattie BR, Booth IW, Botting BJ. Congenital anterior abdominal wall defects in England and Wales 1987-93: A retrospective analysis of OPCS data. BMJ 1996;313:903-6.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]
4.Kazaura MR, Lie RT, Irgens LM, Didriksen A, Kapstad M, Egenaes J, et al . Increasing risk of gastroschisis in Norway: An age-period-cohort analysis. Am J Epidemiol 2004;159:358-563.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.Department of Health. Annual Report of the Chief Medical Officer 2004. Gastroschisis: A growing concern. [Online] Available at: = GET _FI LEanddl D = 5330 and Rendition = Web Accessed 04/04/2007 .  Back to cited text no. 5    
6.Schlatter M. Preformed silos in the management of gastroschisis: New progress with an old idea. Curr Opin Pediatr 2003;15:239-42.  Back to cited text no. 6  [PUBMED]  [FULLTEXT]
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17.Stanbridge Rde L, O′Regan D, Cherian A, Ramanan R. Use of a Pulsatile beating heart model for training surgeons in beating heart surgery. Heart Surg Forum 1999;2:300-4.  Back to cited text no. 17  [PUBMED]  
18.Brehmer M, Swartz R. Training on bench models improves dexterity in ureteroscopy. Eur UroI 2005;48:458-63.  Back to cited text no. 18    
19.Penman DG, Fisher RM, Noblett HR, Soothill PW. Increase in incidence of gastroschisis in the South West of England in 1995. Br J Obstet Gynaecol 1998;105:328-31.  Back to cited text no. 19  [PUBMED]  
20.Suita S, Okamatsu T, Yamamoto T, Handa N, Nirasawa Y, Watanabe Y, et al . Changing profile of abdominal wall defects in Japan: Results of a national survey. J Pediatr Surg 2000;35:66-71.  Back to cited text no. 20  [PUBMED]  [FULLTEXT]
21.Schlatter M, Norris K, Uitvlugt N, DeCou J, Connors R. Improved outcomes in the treatment of gastroschisis using a preformed silo and delayed repair approach. J Pediatr Surg 2003;38:459-64.  Back to cited text no. 21  [PUBMED]  [FULLTEXT]
22.Chiu B, Lopoo J, Hoover JD, Almond PS, Arensman R, Madonna MB. Closing arguments for gastroschisis: Management with silo reduction. J Perinat Med 2006;34:234-5.  Back to cited text no. 22    
23.Fischer JD, Chun K, Moores DC, Andrews HG. Gastroschisis: A simple technique for staged silo closure. J Pediatr Surg 1995;30:1169-71.  Back to cited text no. 23  [PUBMED]  [FULLTEXT]
24.Owen A, Marven S, Jackson L, Antao B, Roberts J, Walker J, et al . Experience of bedside preformed silo staged reduction and closure for gastroschisis. J Pediatr Surg 2006;41:1830-5.  Back to cited text no. 24  [PUBMED]  [FULLTEXT]
25.Blakelock RT, Harding JE, Kolbe A, Pease PW. Gastroschisis: Can the morbidity be avoided? Pediatr Surg Int 1997;12:276-82.  Back to cited text no. 25  [PUBMED]  
26.Allotey J, Davenport M, Njere I, Charlesworth P, Greenough A, Ade-Ajayi N, et al . Benefit of preformed silos in the management of gastroschisis. Pediatr Surg Int 2007;23:1065-9.  Back to cited text no. 26  [PUBMED]  [FULLTEXT]
27.Kidd JN Jr, Jackson RJ, Smith SD, Wagner CW. Evolution of staged versus primary closure of gastroschisis. Ann Surg 2003;237:759-65.  Back to cited text no. 27  [PUBMED]  [FULLTEXT]
28.Nataraja RM, Ade-Ajayi N, Curry JI. Surgical skills training in the laparoscopic era: The use of a helping hand. Pediatr Surg Int 2006;22:1015-20.  Back to cited text no. 28  [PUBMED]  [FULLTEXT]

Correspondence Address:
Niyi Ade-Ajayi
Department of Paediatric Surgery, King's Hospital, Denmark Hill, London SE5 9RS
United Kingdom
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0189-6725.54766

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]

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