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Gastroschisis is characterised byeviscerated bowel herniated through a

congenital abdominal wall defect invariablyto the right of the umbilicus, which isdistinctly different from exomphaloswhereby the bowel is covered by amembrane (FIGURE 1a and 1b). Worldwide,gastroschisis has become a growingconcern and in the last three decades therehas been a steady increase in the prevalenceof gastroschisis; with the UK being noexception. Currently, for all maternal agesthe prevalence of gastroschisis in theBritish Isles is 4.0 per 10,000 live births.However more worryingly is theunexplained increase in incidence ofgastroschisis in the last 10 years from 8.9 to24.4 per 10,000 live births to mothersyounger than 20 years of age1.

Normal development of the anteriorabdominal wall involves complex celldifferentiation, growth and migrationduring the first trimester of pregnancy,converting the embryo from a flat disc ofgerminal cells into a cylinder by the fourthweek of gestation. By the tenth week theanterior abdominal wall fuses in themidline on return of the bowel to theabdomen following ‘physiologicalherniation of the midgut’ into theumbilical cord2. Unfortunately, thepathogenesis of gastroschisis remainspoorly understood. The most widelyaccepted theory is the premature regression

Gastroschisis: putting the bowel backsafelyGastroschisis is an anterior abdominal wall defect which is an increasing problem in the UK. Thisarticle outlines the rationale of the most common postnatal surgical management strategies tosafely reduce the eviscerated bowel and close the defect.

Anthony D Owen MBChB MRCSSpecialist Registrar Paediatric SurgeryDepartment of Paediatric SurgeryLeeds Teaching Hospitals NHS Trustantowen35@mac.com

Sean Marven MBChB FRCS(Paed)Consultant Paediatric SurgeonPaediatric Surgical UnitSheffield Children’s Hospital

Julie BellRGN, RSCN, ENB 998, 415, 904Team LeaderNeonatal Surgical UnitSheffield Children’s Hospital

Keywords

abdominal wall defect; gastroschisis; silo

Key points

Owen A.D., Marven S., Bell J.Gastroschisis: Putting the bowel backsafely. Infant 2009; 5(2): 40-44.1. The overall survival of gastroschisis in

developed countries is greater than90%.

2. Preformed silo staged closure makesgood physiological and economicalsense and has similar outcomes toimmediate operative fascial closure.

3. Complex cases (intestinal atresia,perforation, necrosis, stenosis, volvulus)have worse outcomes than simplecases.

4. Further research of both theepidemiology and postnatalmanagements are required tounderstand and thus preventgastroschisis or minimise morbidity.

of the omphalomesenteric artery at anearly embryonic stage, causing a fullthickness defect approximately 2cm indiameter in the anterior abdominal wall3.

The postnatal management ofgastroschisis has evolved considerably overthe last fifty years and overall 90% ofneonates are expected to survive, which ismost likely attributable to advances inneonatal intensive care and thedevelopment of parenteral nutrition. Now,the focus of management is shifting awayfrom reducing mortality, towards reducingmorbidity. A vast array of surgicaltechniques have been described andcontinue to evolve in an effort to providethe best possible outcome but a number ofkey principles remain constant:� Reduce the eviscerated bowel safely� Close the defect with a cosmetically

acceptable outcome� Support nutrition until full enteral feeds

are established� Identify and treat associated anomalies� Recognise and treat abdominal, wound

and bowel complications.

Pre-operative managementAs a result of antenatal screeningprogrammes in the UK over 97% ofneonates born with gastroschisis arediagnosed antenatally4, providing an idealopportunity for a paediatric surgeon toadequately inform the parents of this rare

FIGURE 1a Eviscerated bowel in gastroschisis.FIGURE 1b Membrane covering bowel inexomphalos.

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condition, expected treatments, outcomesand complications. Simultaneously,arrangements should be made to ensuredelivery in a tertiary centre whereunforeseen complications can be dealt withby the relevant expertise and unnecessarytransfers can be avoided. It makes goodsense to transfer in utero from peripheralhospitals if possible. Presently, there is noevidence to suggest any benefit ofcaesarean section for delivery5 and in theUK most centres elect for vaginal deliveryat 37 weeks’ gestation to avoid late fetal loss– caesarean is only indicated for maternalor fetal complications.

Immediately postpartum the childshould be stabilised as for any otherdelivery. In addition, gastric decompressionis mandatory and a large bore nasogastrictube should be inserted at an early stage.The eviscerated bowel must be covered andsupported by wrapping it in cling-filmwhich acts as a protective barrier and servesto minimise heat and fluid loss (FIGURE 2).Whilst applying the cling film it is essentialthe evsicerated abdominal contents aresupported centrally on the abdomen so thatneither the bowel nor the mesentery istensioned or twisted in order to maintainbowel perfusion.

Alternatively, if the infant ishaemodynamically stable, a preformed silocan be put in position by a paediatricsurgeon in the delivery room, instead ofusing cling-film. The silo provides superiorcentral stability and protection, as thebowel does not need to be exposed againuntil the defect is closed. Fluid lost fromthe bowel is rich in protein and the authorsroutinely use human albumin solution4.5% to replace these losses and forresuscitation when required. Antibioticsshould be started empirically and

defect closure may be achieved primarilyor as a staged procedure, either of whichcan be achieved under general anaesthesia(GA) or at the bedside, but the single mostimportant factor is safety and theavoidance of abdominal compartmentsyndrome.

Primary reduction of gastroschisis

Until recently it has been widely acceptedthat emergency surgery and operativefascial closure (OFC) under GA offers thegreatest chance of survival with minimalmorbidity and only when OFC is unsafe isa staged technique employed6,7. Reductionof the eviscerated contents describes thefirst stage of OFC and is most frequentlyperformed under GA within a few hours oflife in the emergency setting.

At this early stage the bowel is usuallyoedematous and reduction can be difficultdue to the large volume of bowel.Frequently the defect requires enlarging toreduce the oedematous bowel andstretching of the abdominal wall has beendescribed to increase the abdominaldomain. However, the resultinginflammation and oedema from theincision and stretching most likely negatethese efforts and only serve to increasepain. In addition the neonate is oftenparalysed during OFC allowing theabdomen to accommodate the bowel withgreater ease, but this makes assessment ofthe neonate’s behavioral characteristicsimpossible with reliance predominantly oncardiac and respiratory parameters toassess the intra-abdominal pressure.

This lack of information promptedBianchi to develop ward reduction (WR)whereby reduction and closure areperformed with the neonate conscious(FIGURE 3) observing both physiological

continued until the bowel has beenreduced and the defect closed.

Reduction of the visceraAt birth the macroscopic appearance of thebowel is highly variable ranging fromalmost entirely normal to severelyinflamed, thickened, shortened bowel thatis non-compliant and difficult to handle.Bowel injury may be a consequence ofinjurious substances within the amnioticfluid in which the eviscerated bowel isbathed, or secondary to bowelhypoperfusion resulting from constrictionof the mesentery at the defect, or acombination of both6,7. Reduction of theviscera is largely dependent on the degreeof viscero-abdominal disproportion thatusually worsens with the severity of bowelinjury and decreasing abdominal capacity,which is frequently underdeveloped.

In an effort to increase the abdominaldomain some authors have describedmilking the bowel of its contents andperforming bowel washouts but these havebeen shown to be ineffectual8. However, aspreviously mentioned gastric decom-pression during reduction is mandatory toaspirate both fluid and swallowed air andthis does aid bowel reduction.

Significant viscero-abdominaldisproportion encountered at theprocedure makes abdominal closurefollowing reduction difficult or ‘tight’. Asudden rise of intra-abdominal pressuremay compromise bowel perfusion andcause cardio-respiratory embarrassment,which if unrecognised quickly progressesto abdominal compartment syndrome andits potentially devastating physiologicalcomplications of renal failure, sepsis, bowelischaemia and wound complications.

Reduction of the eviscerated bowel and

FIGURE 2 Eviscerated bowel wrapped in cling-film supported centrallyon the abdomen with the neonate supine.

FIGURE 3 “Ward reduction” technique for gastroschisis.

and behavioral parameters to prevent overenthusiastic reduction9. However, he wasnot the first to describe this practice;William Fear in 1878 described the firstsuccessful management and survival of achild born with gastroschisis. Obviouslythe procedure was performed withoutanaesthesia and closure achieved “with askein of thread”10. Despite initialencouraging results with WR othersreported unsatisfactory outcomes and thistechnique is used infrequently11.

Staged reduction of gastroschisis

Staged techniques temporarily increase theabdominal domain by using a silo, orrarely a patch, allowing the bowel oedemato reduce and the newborn time togradually acclimatise to the increasingabdominal contents thus avoiding thesudden increase in intra-abdominalpressure observed in OFC. Traditionally,‘custom silos’ have been fashioned from awide variety of materials, most commonlySilastic® or Gortex® sheets, and sutured tothe fascial edge, invariably after the defecthas been enlarged (FIGURE 4). The bowel isgradually reduced within the silo over anumber of days and the abdomen closed,frequently resulting in an uneven crimpedscar and poor cosmetic outcome. Manufactured or ‘preformed silos’ (PS) arenot a new invention and were firstintroduced by Shermeta in 197514 but haveonly become popularised within the lastdecade. PS do not require cutting orsuturing to the fascia and have theadvantage of being able to be sited in thedelivery room or the neonatal unit,obviating the need for a GA. At the bedsidethe PS can simply be slipped over thebowel and the distal lower ring of the silogently pushed through the defect, fixed inplace with dressings and a ligature securedaround the silo above the bowel to providegentle downward compression. Using both

gravity and compression the bowel issequentially reduced twice a day astolerated, until complete reduction hasbeen achieved (FIGURE 5a, b and c).

As previously mentioned stagedtechniques have traditionally beenemployed only when primary OFC hasbeen deemed unsafe or inappropriate.Historically, staged closure has beenassociated with significant increases in timeto establish full enteral feeds, length ofhospital stay, and complications includinghigher rates of sepsis and problems withsilo detachment9,10. However data from alarge multi-institutional study by Singh(2003) and more recently a randomisedcontrolled trial by Langer and colleagues(2008) do not support these findings anddemonstrated no significant differencesbetween OFC and staged techniques forthe aforementioned outcomes15,16.

Closure of the defectClosure of the defect following successfulreturn of the eviscerated bowel to theabdomen may be managed using operativeor non-operative methods. Whatever thestrategy, preservation of the umbilical cordis essential for a satisfactory cosmeticoutcome. Following primary or stagedreduction of the bowel under GA thedefect is usually closed with fascial suturesthus approximating the fascia and the skin

above. Suture closure at the bedsidewithout GA is more problematic due to thesmall volumes of local anaesthetic that canbe administered and movement of thenewborn during closure.

The defect seen in gastroschisis has atendency to close naturally in the absenceof high intra-abdominal pressures,intervening bowel and sepsis. Sutureless orplastic closure of the defect, using onlyadhesive dressings, takes advantage of thisphenomenon and this technique of closureis frequently used at the bedside withoutGA. The authors routinely use preformedsilos at the bedside without GA andperform a plastic sutureless closure whereappropriate. Once the PS has beenremoved the umbilical cord, which hasbeen preserved, is gently pulled to thecontralateral side to appose the skin edges.Adhesive strips, then slit transparent IVdressings secure the skin edges ensuringthe defect remains closed and these are leftin place for 7-10 days17. The umbilical cordis allowed to protrude through the centreof the dressing and dry out whichencourages the defect to cicatrise and closethe abdomen (FIGURE 6a and b).

Fortunately patches are rarely used forthe management of gastroschisis as thedefect invariably can be closed followingsilo bowel reduction. Patches are fashionedfrom a variety of synthetic andbiomaterials. Synthetic materials includingpolypropylene mesh, Gortex® andreinforced silicone, are used as a temporarymeasure with the aim of removing thepatch and closing the defect ideally at thefascial level. However, synthetic materialssutured to the fascia cause a variable degreeof inflammation and oedema makingclosure difficult with a subsequent poorcosmetic appearance. Biomaterials such asporcine-derived materials or acellularhuman allografts of dura or dermis areused when skin coverage is desirable and

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42 V O L U M E 5 I S S U E 2 2 0 0 9 infant

FIGURE 4 ‘Custom’ made silo fashioned fromsilicone sheets sutured to the fascia.

FIGURE 5a Application of preformed silo. FIGURE 5b Preformed silo secured withligature tied above bowel to providedownward compression.

FIGURE 5c Preformed silo sequential bowelreduction.

are designed to encourage ingrowth ofvascular tissue so they can be left inpermanently18-20.

Simple and complex gastroschisisSimple gastroschisis describes intact bowelthat is not compromised or breached. Incontrast complex gastroschisis is definedby the presence of one of five criteria:intestinal atresia, necrosis, perforation,stenosis or volvulus. Fortunately, mostreports refer to a proportion of 90% forsimple and only 10% for complex cases ofgastroschisis. Needless to say, complexcases have a significant effect on outcomewith inpatient mortality rates of 2.9% forsimple and 8.7% for complex, with amedian length of hospital stay of 28 vs. 67days respectively.

Complex gastroschisis tests a surgeon’sexpertise and ingenuity to the limit and inan effort to optimise outcomes a combin-ation of the aforementioned techniquesare utilised and frequently a number ofprocedures are required. The loss ofintestinal length seen mainly in complexcases may result in short bowel syndromewhereby the bowel is unable to absorb therequired nutrients to sustain life.Prolonged periods of parenteral nutritionare required whilst the bowel undergoesadaptation and numerous procedures toincrease the bowel length have beendescribed. However, despite thesemeasures some cases will require smallbowel transplantation if they meet therelevant criteria to undergo this extremelyextensive surgery. Unfortunately, themortality for small bowel transplantationis very high; 50% of those on the waitinglist die before transplantation and 50%receiving donor bowel die within fiveyears. The impact of these treatments and

poor outcomes on the family unit cannotbe underestimated.

DiscussionThe epidemiology of gastroschisis mostlikely will evade understanding and henceprevention for many years to come. Onlyin 2004 did the Chief Medical Officer issuea report on the growing concern ofgastroschisis and recommended that moreresearch be commissioned to establish thecauses of gastroschisis and investigate theincreasing prevalence1. In response and forthe first time, a collaboration between theNational Perinatal Epidemiology Unit(NPEU) based in Oxford and the BritishAssociation of Paediatric Surgeons (BAPS)has enabled capture of pre- and postnatalgastroschisis data throughout the UK4. Thestudy is ongoing but will hopefully helpunravel the causes of gastroschisis that aremost likely multifactorial.

Until then, gastroschisis will continue totest paediatric surgeons worldwide toachieve the highest survival rates andlowest morbidity, using an armoury oftechniques for both simple and complexgastroschisis. Due to the ever-expandingarray of surgical techniques and materialsused to tackle gastroschisis it is difficult toascertain which method should be usedwhen and for whom. In short, a ‘one sizefits all’ approach does not apply.

Robust evidence in the form ofrandomised controlled trials is distinctlylacking and often treatment is instigated onsurgeon preference and then tailored ormodified on an individual basis. Thus,management strategies for gastroschisiswithin a tertiary centre, let alonenationally, are not standardised makingrecruitment into protocolised studies verydifficult. With this in mind the large

observational studies or randomised trialsrequired to identify superior methods maynot be forthcoming.

The postnatal surgical management ofgastroschisis continually evolves and seemsto have gone full circle with stagedreduction becoming more popular.Although the evidence is lacking, stagedreduction seems to make goodphysiological sense allowing the boweloedema and inflammation to reduce priorto definitive abdominal wall closure, thusreducing the risk of abdominalcompartment syndrome. Preformed siloscan safely be placed at the bedside out ofnormal working hours without the needfor GA, which may also have significantfinancial implications.

Finally, in today’s climate aesthetics arealso an important consideration for bothpatients and parents, but safety and goodsurgical practice should never be compro-mised at the expense of cosmesis, as bothmay be compromised in the long-term.

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FIGURE 6a Fully reduced bowel following preformed silo sequentialreduction.

FIGURE 6b Plastic sutureless closure of gastroschisis.

J Pediatr Surg 2008; 43: 1685-90.

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