Omphalocele (OC) represents the most common entity of congenital abdominal wall defects. In OC, eviscerated abdominal organs herniate through the umbilical cord which is covered by a three-layered membrane consisting of peritoneum, Wharton's jelly, and amnion. The extent of evisceration often correlates with the abdominal wall defect size and may comprise intestine and solid organs as liver, spleen, bladder, or gonads. The current prevalence of OC is 1.24 per 10.000 live births (1). The primary intention in OC treatment is a timely return of abdominal organs back into the peritoneal cavity and closure of fascial and skin defect without compromising the visceral and systemic perfusion. In contrast to the treatment of giant OC, which are generally defined by a defect size larger than 5 cm and/or a herniation of more than 50% of liver, minor OC may often be managed by primary closure (2, 3). Giant OC often requires gradual reduction of the external peritoneal viscera in order to minimize the risk for cardiopulmonary complications prior to either surgical tension-free abdominal fascial closure or a nonoperative closure allowing for epithelization of the OC sac with delayed fascial closure. Recently, vacuum (VAC) therapy has been introduced for the treatment of complicated cases in OC (4–11). However, VAC therapy has mostly been implemented after failure of another primary OC repair method with only one case series by Aldridge et al. (12) in which VAC therapy was utilized by primary intention within first two days of life as an adjunct to the staged gravitational OC reduction until complete abdominal reintegration of giant OC with time to fascial closure lasting several months. In the present study, we aimed for describing our experiences with the staged OC reduction approach in adjunct with primary vacuum application started within first hours of life.

We present our preliminary experience with simultaneous VAC application as an improvement of the staged gravitational reduction technique in six patients with giant OC. No consensus as to the preferable surgical treatment of giant OC exists, which is mainly due to the heterogeneity of applied methods (15). Since its introduction in 1997 (16, 17), the vacuum technique has been subject to a large spectrum of applications in the adult population. However, it has not yet proven the same efficacy and safety in children (18). Nonetheless, the literature on the efficacy of vacuum therapy seems promising in terms of the treatment of complicated pediatric wounds as pressure ulcers, extremity wounds, surgical wound dehiscence, skin grafting, or complex abdominal defects (9–11, 19–21) and also congenital abdominal wall defects (5, 22). A review of the literature on VAC application associated with omphalocele revealed that VAC has mostly been implemented as secondary salvage therapy after failure of another primary OC repair method (4–11, 23) (Table 2). It is worth mentioning that reported cohort sizes were small ranging from one to three patients or were not reported at all (9, 11). Time to abdominal fascial closure ranged from 17 days to ∼29 months. Time to full enteral feeds was not documented in all cases, with only one exception (8). LOS ranged from 60 to 78 days (6–8, 12) or was also not reported (4, 5, 9–11, 23).

Presented procedure has only been reported once by another group (12) (Table 2) in an equivalent setting, characterized by eight patients of similar gestational age with start of VAC therapy within the first two days of life and comparable VAC change intervals, but with much longer duration until fascial closure (8–9 months vs. 9 days in our study) and LOS (70 days vs. 22 days in our study). Obtained durations until first and full oral feeding were comparable to the results obtained by Aldridge et al. (6 and 19 days vs. 3 and 20 days in our study). Noteworthy, in the present study, exerted vacuum levels were higher (−80 mmHg) than those used by Aldridge et al. (−25 to −50 mmHg). In this context, recommended negative pressure setting in congenital abdominal wall defects ranges from −50 to −75 mmHg (4, 24, 25). By vacuum levels exerted more positive than a certain threshold, an insufficient or decelerated reintegration of visceral contents could occur. This might be one explanation for the comparably fast reduction of eviscerated OC contents in our study compared to that by Aldridge et al. Of note, higher vacuum levels for OC reduction may also induce higher transient intra-abdominal pressure levels with increased risk for cardiorespiratory depression. However, we did not observe any signs of cardiorespiratory compromise within our continuously monitored cohort.

Comparing the different treatment strategies for giant omphaloceles (26–33) (Table 3) and the presented method, LOS was only shorter in one series by Morabito et al. (27), using the vertical cord traction followed by the compression reduction method. The time to full oral feeds of 20 days in our VAC method was slightly longer than in most of the comparative studies (27–30), or was not reported (26, 32, 33). With regard to time until fascial closure, only three groups (24) reported shorter periods than in the present study, ranging from 4 to 7 days utilizing vertical cord traction followed by compression reduction method (27), the delayed external compression reduction method (28), or the gravitational autoreposition suture method (31), respectively. In concordance with our data, Mehrabi et al. (29) also elicited a ventilation duration of 5 days by utilizing an intraperitoneal tissue expander and traction of abdominal muscles (camel-litter method) in six OC patients. In all other studies, durations of ventilation were longer, ranging from 7 to 11 days (27, 28, 30, 31), or were not even mentioned (26, 32, 33). Noteworthy, except one study by Abello et al. (33) utilizing a constructed silo with an adhesive hydrocolloid dressing in 40 neonates, neither of the reported studies had large sample sizes (ranging from 6 to 22 patients) and therefore associated malformations as pulmonary insufficiency may have large impact on average procedural parameters, as was the case in our first patient with pulmonary hypoplasia (PH) (Table 1). By excluding patient 1, median duration of ventilation decreased from 5 (0–12) days to 1 (0–9) day only. Over the course of the study, the individual ventilation duration decreased (supplementary Figure S1B), reflecting a possible learning curve. However, this has to be confirmed by larger studies.

The presented VAC method combines some advantages, as being noninvasive in terms of OC sac preservation until fascial closure. Thus, the achieved intestinal nontouch procedure also diminishes risk for development of intra-abdominal adhesions. In addition, VAC application promotes a gentle pressure elevation by intra-abdominal dead space obliteration with a decreased risk for cardiorespiratory compromise. It is important to mention that the VAC method may reach its limits in those 36%–57% (34, 35) of cases with giant OC that present with associated pulmonary hypertension or PH. Since this condition may worsen with increasing abdominal pressure, a careful cardiorespiratory monitoring under reduction of OC contents is mandatory. Given that our method was well tolerated in patient 1 with PH, we do not consider this comorbidity an exclusion criterion at this early stage of experience.

In our series, the VAC method permitted an early enteral feeding. In general, VAC is supposed to minimize bacterial biioburden (24). Consecutive VAC changes might be performed under less invasive (awake caudal) modes of anesthesia without intubation at bedside, thus lowering the risk for associated side effects in this vulnerable cohort. Furthermore, the presented method can easily be learned and may be advantageous in case of complications, such as a patent OMD or an OC sac rupture as seen in patient 3. By reducing time until fascial closure, risks for associated morbidities inherent to a prolonged hospitalization in this delicate age group may be mitigated by presented VAC method. Finally, repair of OC with simultaneous neo-umbilicoplasty is of high relevance regarding the patient's satisfaction and self-identification (36–38). In general, an umbilicus located in the midline at two-thirds of the distance from the symphysis to xiphoid is considered cosmetically acceptable (39). In our series, the position of the neo-umbilicus was dictated by the umbilical arteries and thus at the anatomically correct position.

In neonates with giant OC, VAC constitutes a promising and technically feasible enhancement of the staged gravitational reduction method when primary closure seems questionable. Even in complicated cases with OC membrane defects or associated intestinal malformations, the presented technique seems to be safe and effective. Only in one previous series, VAC has been used in a similar manner for primary OC treatment, but with longer time until fascial closure. In summary, this study underlines the importance of VAC as an enhancement enabling an accelerated restoration of abdominal wall integrity in neonates with giant OC within their first 2 weeks of life, thus minimizing associated comorbidities inherent to a prolonged hospitalization. Therefore, we provide evidence that VAC is a promising technique to improve the treatment of OC and should be investigated further in future studies.