In this study, we present the first experience in traction-assisted abdominal wall closure in newborns with GOC and GS using the fasciotens®Pediatric traction device. The traction device was applied in 10 cases of GOC and 6 cases of GS. All patients underwent a staged closure of the defect in combination with continuous traction to the abdominal wall. Complete abdominal wall closure was achieved in all patients after a median time of 7 days (range 4–22 days) in GOC and of 5 days (range 4–11 days) in GS.

Overcoming the viscero-abdominal disproportion is one of the main therapy challenges in patients with congenital abdominal wall defects. Historically, the introduction of the staged closure technique with multiple variations of prosthetic silos between the late 1960s to the mid 1990s has added an innovative treatment option for patients with large defects [13,14,15, 17]. The silos, either handsewn or preformed, serve as a temporary extension of the abdominal cavity enclosing the displaced organs and protecting the newborn from heat and fluid loss. The silos are usually suspended to the top of the child’s incubator to keep it upright and folded daily to enhance the gravitational descent of the viscera into the abdominal cavity. The suspension and folding of the silo bag as well as the organ descent into the abdomen result in a progressive distension of the abdominal wall ideally enabling its closure. In some cases, the silo is followed by an interposition of an alloplastic patch at the level of the fascia with stepwise size reduction to further approximate the fascia lines.

Traction-assisted staged closure

To enhance the abdominal distension, some surgeons have added external traction to the abdominal wall documenting that the abdominal wall in newborns is responsive to stretching procedures [31,32,33,34,35, 37]. The most prominent study by Patkovsky and colleagues included a series of 8 patients with OC and 21 patients with GS treated with external traction. Traction was applied via a pulley system and a full-thickness abdominal wall closure was achieved in less than 6 days in all patients [31]. In another publication, Svetanoff and colleagues treated one patient with a large GS with bowel and liver outside of the abdomen. They applied a silo with external traction for 1 month [34]. Morabito and colleagues described a traction-compression method by pulling the umbilical cord in 11 patients with GOC. Complete fascial closure was achieved in 7 out of 11 patients after 5 days of traction [33]. In a report by Mehrabi et al., fascial traction was applied via a support frame arching over the child in 6 patients with GOC and 2 patients with GS. In combination with intraabdominal tissue expanders complete closure was achieved in 14–32 days [35]. Uecker et al. reported a traction procedure without resecting the amniotic sac in GOC cases. They achieved complete closure in 7 out of 12 patients in less than 7 days (except for one patient with pulmonary hypoplasia after 40 days). In 5 patients, however, only skin closure was accomplished and a delayed fascial closure had to be done in the following months [32]. In our case series, abdominal wall closure including the fascia was accomplished in all patients. The time to fascial closure (less than 22 days in GOC and less than 11 days in GS) was within the range of the published studies stated above. However, with growing experience in the application of fasciotens®Pediatric, the duration of traction and time to abdominal wall closure may become shorter in the future.

Patkovsky et al. applied a traction force of 30–40% of the patients’ body weight. Other publications have not specified the degree of traction. Two authors reported, that the maximum traction force was achieved when the child’s back was gradually lifted off the bed [33, 34]. In the cases of the here presented study, traction force did not exceed 1000g. In relation to the patients’ body weight (in grams) the traction force ranged from 16- 35% in GOC and 26–46% in GS. None of the patients were lifted off the mattress. However, two tear-outs of traction sutures occurred in two GOC cases at a traction force of 32% and 34% of the patient’s body weight. The optimal traction force will need to be determined systematically in future trials.

Amniotic sac sparing procedure

Regardless of the closing method some pediatric surgeons preserve the amniotic sac in patients with OC [29, 30, 38, 39]. In our series, the amniotic sac was initially not resected in 5 out of 10 GOC cases. As mentioned before, in 2 of these patients, a traction suture and a Gore-Tex® patch tore out of the tissue and had to be replaced. Fascial closure was not affected in these patients. However, the reason for the migration of the traction sutures needs to be critically discussed. In cases in which the amniotic sac was not resected, traction sutures were placed at the rim of the defect (amnio-cutaneous line). It is important to consider, however, that the amnio-cutaneous line is not generally equivalent to the margin of the abdominal wall fascia [30, 40]. The tissue at the amnio-cutaneous line may, therefore, be less resilient for traction which may explain the tear-outs in our 2 patients.

Besides the loss of tissue resilience, the traction progress may also be less efficient when traction sutures are not placed directly to the fascia. Traction to the rim of the defect or to the umbilical cord will only transmit traction forces indirectly to the fascia. As mentioned above, Uecker et al. and Morabito et al. did not achieve fascial closure in around 40% of their cases [32, 33]. In our cohort, complete closure was achieved in all patients with amniotic sac saving procedures. However, we saw a non-significant tendency towards a longer median time to closure between patients without and with resection of the amniotic sac (9 vs. 5 days, respectively). Aljahdali and colleagues addressed the problem of securely fastening a silo to the abdominal wall without resecting the amniotic sac. They advised to dissect the fascia via a skin incision a couple millimeter proximal to the amnio-cutaneous line for a secure anchorage of the silo [40]. It will be important to pay close attention to the efficiency of different traction applications to determine the optimal procedure in the future.

Delayed closure technique

There are many pros and cons regarding the optimal treatment strategies for large complicated abdominal wall defects. Treatment is usually guided by the pediatric surgeon`s preference and experience. Presumably, the cases presented in this study could have been successfully treated by other techniques as discussed above [19,20,21,22,23]. Amniotic sac epithelization (“paint and wait”) for the treatment of GOC, for example, is a preferred approach in many pediatric surgery institutions worldwide [38, 39]. It offers the advantage that no mechanical ventilation is needed in the newborn and enteral feeding can be started soon after birth [5, 39]. In addition, the non-operative approach of “paint and wait” has to be considered in children with OC-associated comorbidities such as pulmonary hypoplasia, pulmonary hypertension and severe congenital cardiac defects [38, 41,42,43]. “Paint and wait”, however, is a lengthy procedure lasting weeks and months before complete epithelization is achieved entailing the risks for infections and failure [30, 39]. Once epithelization is achieved, patients usually present with large ventral hernias. The reconstruction of the abdominal wall around these hernias often need meticulous plastic operations later in life with chances for failure and severe scaring [10, 24, 28, 39]. Traction-assisted fascial closure in the newborn period, as reported here, may render these drawbacks of delayed closure unnecessary. In the future, comparative studies will need to elaborate the advantages of each technique.

General anesthesia and ventilation

In line with most reports on staged closure procedures, the majority of patients in our case series were kept under GA with paralysis during the treatment with external traction [31,32,33,34,35]. The median time of ventilation of 12 days was comparable to other reports on abdominal wall closure in GOC with 5–11 days of ventilation [12, 32, 33, 35, 44, 45]. In GS, the time on the respirator is reported between 2 and 7 days in staged closure and 3–5 days in primary closure [46,47,48,49]. Here, we report a median of 7 days in large complicated GS which is in the upper range of the literature cases.

In 3 of our cases, no GA was given during traction. In these patients, abdominal wall closure was achieved after 9 and 20 days in GOC and 11 days in GS. It will be of interest to investigate in a larger subset of patients whether GA with paralysis is necessary for adequate expansion of the abdominal wall or if GA and/or paralysis can be limited without compromising of the time to closure.

Compartment syndrome

In this study, we did not experience any clinical signs of a compartment syndrome causing insufficient mechanical ventilation or anuria. In selected cases, we changed the direction of traction from vertical to diagonal after the viscero-abdominal disproportion was resolved. Diagonalization appeared to accelerate the approximation of the fascia thus facilitating tension-less closure. There was no negative influence on the intra-abdominal pressure and ventilation after diagonalization.

Complications

There was a skin dehiscence after abdominal wall closure in GS leading to a reoperation in one of our patients. In this case, the skin had not been included in the traction appliance. At the time of fascial closure, the skin could only be closed under tension. In all other cases, the skin was included in the traction process leading to enough skin overlap during fascial closure. There was no surgical site infection and no traction-related abdominal wall necrosis, nor were there any safety-related events in the application of the traction aperture. Umbilical hernias occur at a rate of up to 18% after staged and 9% after delayed closure in GOC and is seldomly reported in GS with sutured repair [26, 47]. During the follow-up of 4 to 22 months, there was no formation of an umbilical or incisional hernia in the here reported series.

Limitations

The small number of patients, the lack of a control group, and the short follow-up time are the main limitations of this study.

Recommendations and further applications

The application of the traction device, fasciotens®Pediatric, has not been described in the treatment of GOC and GS before. Therefore, the best practice of the traction procedure using the device has to be still defined. Based on the first experiences of the 16 cases presented in this study, we summarized preliminary recommendations for the application of fasciotens®Pediatric in GOC and GS. However, these recommendations are not obligatory operating instructions. They should rather initiate future research to improve the treatment for GOC and GS.

Further applications of fascial traction for abdominal wall repair such as short intra-operative fascial traction (IFT; e.g. 30 min.) to achieve primary fascial closure and fascial traction for delayed abdominal wall closure of ventral hernias after “paint and wait” could also be considered in the future. In adults, successful IFT has recently been reported for large ventral hernias with a closure rate of 90% [50].

Box 1 Preliminary recommendations in the application of fasciotens®Pediatric in GOC and GS

Adjust traction force to around 30% of the patient`s body weight in grams

Expose the fascia surgically to apply the traction directly to the fascia

In case the amniotic sac is not resected and the fascia is not exposed surgically, pay close attention to securely fasten the traction sutures to the fascia and not only the skin

Preferably, do not apply single traction sutures directly to the fascia but interpose an alloplastic mesh between the fascia and the traction sutures to transmit the traction force evenly along the fascia lines

Cover the abdominal wall defect with a handsewn or preformed spring-loaded silo