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The use of intraabdominal tissue expanders as a primary strategy for closure of giant omphaloceles
Journal of Pediatric Surgery (2009) 44, 178–182
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The use of intraabdominal tissue expanders as a primary strategy for closure of giant omphaloceles Abigail E. Martin, Adeel Khan, Daniel S. Kim, Christopher S. Muratore, Francois I. Luks ⁎ Division of Pediatric Surgery, Department of Surgery, Hasbro Children's Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA Received 3 October 2008; accepted 7 October 2008
Key words: Giant omphalocele; Abdominal wall defect; Tissue expanders
Abstract Background: Giant omphaloceles present a unique challenge to pediatric surgeons because of the difficulty in obtaining timely, tension-free closure of tissues over the defect. Reports of the use of tissue expanders in the subcutaneous space, intramuscular space, or intraabdominal cavity have illustrated the usefulness of this technique to provide biologic closure of abdominal wall defects. However, these reports have focused on use of tissue expanders as a second-line treatment after other options, such as silastic silos or attempted primary closure, have failed. Methods: We report 2 cases in which intraabdominal tissue expanders were used as a primary strategy to obtain closure of giant omphalocele defects. Case Reports: The first patient was a baby boy born at 36 weeks by date who was prenatally diagnosed with a giant omphalocele. An intraabdominal tissue expander was placed at 2 weeks of age. The tissue expander was removed and his abdomen was primarily closed at 8 weeks of age. The second patient was born at 25 weeks gestation as part of a twin gestation with severe intrauterine growth retardation (600 g birth weight). Bedside reduction was not attempted because of severe pulmonary hypertension and significant loss of abdominal domain because of herniated liver and bowel. At 8 months of age, she underwent laparoscopically assisted placement of an intraabdominal tissue expander. At 9 months of age, the tissue expander was removed, all abdominal viscera were reduced, and the defect was closed using only an 8 × 8-cm piece of AlloDerm (LifeCell, Branchburg, NJ). Both children are currently at home and doing well. Conclusions: We believe that early use of intraabdominal tissue expanders provides a more expedient method of obtaining closure of the defect in giant omphaloceles. © 2009 Elsevier Inc. All rights reserved.
An omphalocele is a congenital abdominal wall defect caused by failure of the cephalic, caudal, and lateral folds to fuse at the umbilical ring during the fourth week of gestation.
Presented at the 39th annual meeting of the American Pediatric Surgical Association, Phoenix, AZ, May 27-June 1, 2008. ⁎ Corresponding author. Tel.: +1 401 228 0556; fax: +1 401 444 6603. E-mail address: [email protected] (F.I. Luks). 0022-3468/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2008.10.031
Abdominal viscera, which can include intestine, colon, stomach, and liver, are covered by a peritoneal sac rather than normal abdominal wall musculature and the umbilical cord inserts at the apex of the sac. A giant omphalocele is defined as a defect that measures more than 6 cm and a sac that contains most of the of abdominal viscera including the liver, resulting in significant loss of abdominal domain and an underdeveloped peritoneal cavity [1]. Because of the large discrepancy between abdominal domain and the volume of
Intraabdominal tissue expanders to close grant omphaloceles extraabdominal organs, these defects present a significant challenge to pediatric surgeons. Potential pitfalls encountered when trying to return extraabdominal organs to the peritoneal domain include wound infections with or without the use of prosthetic materials to close the defect, compression of abdominal viscera or major intraabdominal vascular structures, and respiratory and cardiovascular compromise because of elevated diaphragms and high intraabdominal pressure [2-4]. Several approaches have been described to allow closure of giant omphaloceles. Creation of skin flaps to cover the defect, followed by later repair of the ventral hernia was initially described by Gross [5]. Gradual reduction of the viscera using a silo followed by delayed closure of the defect, with or without the use of prosthetic material, has become a popular approach to these defects [2,4,6-8]. Variations on this method include the use of elastic dressings on the sac to provide gradual pressure and reduction of the sac contents or sequential clamping of the sac without prosthetic material [9-11]. Epithelialization of the sac using topical agents followed by delayed closure of the defect has also been used [2,12]. Split-thickness skin grafting placed over absorbable mesh has also been described as a method to allow coverage of the defect until delayed closure of the ventral hernia can be attempted [13]. Tissue expanders placed in either the subcutaneous space or abdominal wall intramuscular spaces have been reported as a method to increase the size of potential skin or muscle flaps before closure [10,14]. Tissue expanders can also be placed intraperitoneally and gradually expanded to allow for
179 stretch of the abdominal wall and increase in abdominal domain. Reported cases in which intraabdominal tissue expanders have been used have focused on using this method after other attempts at reduction with either a silo or elastic compression dressings have failed [15,16]. We describe 2 patients in whom intraabdominal tissue expanders were used as the primary method to increase abdominal domain and allow for closure of the giant omphalocele defect.
1. Case reports 1.1. Case 1 The first patient was a baby boy born at 36 weeks gestation (birth weight, 2260 g). He had a giant omphalocele with approximately 75% of the liver and intestine visible within the intact sac (Fig. 1A). The sac was initially covered with sterile gauze while workup for other congenital abnormalities could proceed. He was found to have an atrial septal defect. Because of the size disproportion between the viscera within the sac and the abdominal cavity itself, traditional methods of reduction were not anticipated to be successful. Furthermore, because of the large proportion of the liver within the sac, methods that would compress the extraabdominal viscera risked compromising hepatic venous and caval return. After obtaining informed consent from the parents, an intraabdominal tissue expander was placed at day of life 19 (weight, 2610 g). A Pfannenstiel incision was made to allow placement of a saline tissue expander (10 by 13 cm,
Fig. 1 Case 1. A, Appearance of giant omphalocele shortly after birth. B, Infusion port of tissue expander seen exiting the right inquinal incision with omphalocele sac wrapped in Coban. C, Second operation showing closure of defect after excision of sac and removal of tissue expander. D, Patient at 7 months of age after closure of ventral hernia.
180 500 mL capacity) within the peritoneal cavity (PMT Corporation, Chanhassen, Minn). A right inquinal counterincision was created as an exit site for the inflation port that remained extracorporeal. The tissue expander was inflated with 50 mL of saline at the time of the initial operation. Over the next several weeks, the tissue expander was gradually inflated to a total volume of 180 mL and the omphalocele sac was dressed with gauze and Coban dressing (Fig. 1B). On day of life 41 (weight, 2860 g), the patient returned to the operating room for definitive repair of the defect. After taking down adhesions between the omphalocele sac and the liver and intestine, the sac was excised and the tissue expander was removed from the peritoneal cavity. The viscera were reduced, skin flaps were created, and the fascia was closed circumferentially leaving only a defect at the center measuring 2.5 by 2.5 cm (Fig. 1C). The skin was closed over this defect, and the patient recovered uneventfully. He returned to the operating room at 4 months of age for definite closure of the remaining ventral hernia. The patient had a good cosmetic result and is currently doing very well at 2 years of age (Fig. 1D).
1.2. Case 2 The second patient was a baby girl born as part of a twin gestation at 25 weeks with severe intrauterine growth retardation (birth weight, 600 g). She had bronchopulmonary dysplasia requiring tracheostomy, pulmonary hypertension, and a hemodynamically significant patent ductus arteriosus that eventually required ligation. Most of her liver and intestine were within the omphalocele sac. Because of her
A.E. Martin et al. severe pulmonary disease, no attempt was initially made to reduce the viscera, and the sac was instead covered with sterile dressings. By 8 months of age, the sac had completely epithelialized and her pulmonary status had stabilized. A computed tomographic scan clearly illustrated the extreme loss of abdominal domain, with volumetric analysis showing an approximate intraabdominal volume of 1500 mL and the extraabdominal viscera occupying approximately 2700 mL (Fig. 2A and B). She was taken to the operating room at 8 months of age (weight, 7430 g) where a saline tissue expander (15 by 15 cm, 1000 mL capacity; PMT Corporation) was placed using laparoscopic assistance. Initially, a suprapubic 12-mm trocar was placed to allow for laparoscopic inspection of the abdominal cavity and the defect. The tissue expander was introduced through the same incision and allowed to unfurl. A subcutaneous tunnel was created from the anterior left thigh, over the left inquinal ligament and in the peritoneal cavity through which the tubing used for inflating the tissue expander was passed. The infusion port was connected and placed in a subcutaneous pocket over the left anterior thigh. Postoperatively, the tissue expander was inflated to a volume of 120 mL and was gradually increased to a total volume of 1000 mL over the next month. At 9 months of age, the patient returned to the operating room for closure of the omphalocele defect. The abdominal cavity was entered through the omphalocele sac. The tissue expander was removed and the sac was excised (Fig. 2C). She tolerated full reduction of the viscera into the abdominal cavity, but the fascial defect was too large to close primarily and was closed using human acellular dermis (AlloDerm, LifeCell, Branchburg, NJ) (Fig. 2D). At
Fig. 2 Case 2. A, Sagittal view of computed tomographic scan of abdomen and pelvis illustrating most of the viscera in omphalocele sac. B, Three-dimensional reconstruction with volumetric analysis showing 2700 mL volume of extraabdominal viscera and 1500 mL volume of peritoneal cavity. C, Second operation showing excision of the sac and removal of the tissue expander. D, Closure of the fascial defect using AlloDerm.
Intraabdominal tissue expanders to close grant omphaloceles 19 months of age, she remains ventilator dependent and is tolerating feeds via a gastrostomy tube placed during her last surgery. She has not yet undergone final repair of her ventral hernia.
2. Discussion Treatment of giant omphaloceles has remained a challenge for pediatric surgeons despite advances in neonatal medicine. Most traditional methods of treating giant omphaloceles have concentrated on allowing coverage of the defect with a resulting large ventral hernia to be repaired later in life. These approaches take into account the fact that many patients with giant omphaloceles have associated pulmonary hypoplasia and ventilator dependence in which increases in intraabdominal pressure could significantly impair ventilation. Other approaches have used either external compression or gravity itself to reduce the viscera into the abdominal cavity. However, these methods risk ischemic damage to the organs themselves or to other intraabdominal vascular structures. The ideal approach to giant omphaloceles would emphasize decreasing the disproportion between the volume of extraabdominal viscera and intraperitoneal space. Because the viscera cannot become less voluminous, increasing intraperitoneal space becomes the goal and tissue expanders offer the ideal solution to this problem. Subcutaneously placed tissue expanders have been successfully used in other surgical situations in which creation of abdominal wall skin was necessary, including adult patients who had loss of the abdominal wall from either traumatic or infectious events [17,18]. Similarly, tissue expanders have been used to increase the amount of abdominal wall skin in pediatric patients with abdominal wall defects [10,19]. De Ugarte et al [14] presented a novel approach to using tissue expanders placed within the intramuscularly layers of the abdominal wall of a patient with a giant omphalocele, allowing creation of an outer layer composed of skin and internal and external oblique muscles. However, placement of a silo was still necessary to allow reduction of the viscera before the skin and muscle flaps could be closed over the defect. Intraabdominal placement of tissue expanders offers the advantage of creating “tissue flaps” that include all layers of the abdominal wall, including skin, muscle, and peritoneum. This method has already been successfully described in the literature by at least 2 centers. Bax et al [15] described using the tissue expander in a term neonate whose omphalocele defect was small, but most of the liver was in the sac, preventing any compressive type of strategy to reduce the viscera. Foglia et al [16] used intraabdominal tissue expanders in 2 patients, one a neonate with a giant omphalocele in whom silo reduction had failed and one in a 4-year-old girl with a giant omphalocele that had been allowed to epithelialize but had never been repaired because
181 of associated congenital anomalies. Because of the success of intraabdominal tissue expanders in these cases, we used this method as a first-line strategy in the 2 patients presented in this report. Our first patient was a near-term neonate with a giant omphalocele not believed to be amenable to more traditional approaches. We opted against using any type of silo or other compressive method, and instead placed the intraabdominal tissue expander as a primary strategy to increase peritoneal domain. During his second operation, the resulting ventral defect only measured 2.5 by 2.5 cm and did not require placement of any type of graft. The small size of the defect also allowed repair at 4 months of age as an outpatient procedure. We believe the size of his ventral hernia compares very favorably with the larger size ventral hernias that can result from other approaches. Our second patient was a very premature neonate born at 25 weeks gestation with significant comorbidities preventing safe reduction of her extraabdominal viscera by any means. Ultimately, AlloDerm was used to close her fascial defect, but the eventual defect was significantly smaller than would have existed without prior use of the tissue expander. The 2 patients presented in this report illustrate the efficacy and safety of intraabdominal tissue expanders as a means to increase intraabdominal domain in preparation for repair of giant omphaloceles. Initial placement of these devices should do little to affect intraabdominal pressure, but care must be taken over the ensuing days and weeks as the volume within the tissue expanders is increased to avoid any respiratory compromise or visceral ischemia. We cannot report any adverse effects of gradual inflation of the tissue expander, but close monitoring of patients for signs of abdominal compartment syndrome is imperative. Disruption of the omphalocele sac could potentially result from inflation of a tissue expander, although we did not experience this complication in our patients nor did we find reports of this in the literature. Inflation of the tissue expanders should distribute the pressure equally over the abdominal wall tissues and the sac, and by increasing the volume gradually, acute disruption of the sac is very unlikely. The ultimate choice in how to approach such a complex problem as giant omphalocele must be left up to the pediatric surgeon's best judgment. We believe that judicious, early use of intraabdominal tissue expanders can provide a more expedient method of obtaining closure of the defect in giant omphaloceles.
References [1] Minkes RK. Abdominal wall defects. In: Oldham KT, Colombani PM, Foglia RP, et al, editors. Principles and practice of pediatric surgery. Philadelphia (Pa): Lippincott, Williams, and Wilkins; 2005. p. 1103-19. [2] Nuchtern JG, Baxter R, Hatch Jr EL. Nonoperative initial management versus silo chimney for treatment of giant omphalocele. J Pediatr Surg 1995;30:771-6.
182 [3] Hershenson MB, Brouillette RT, Klemka L, et al. Respiratory insufficiency in newborns with abdominal wall defects. J Pediatr Surg 1985;20:348-53. [4] Pacilli M, Spitz L, Kiely EM, et al. Staged repair of giant omphalocele in the neonatal period. J Pediatr Surg 2005;40:785-8. [5] Gross RE. A new method for surgical treatment of large omphaloceles. Surgery 1948;24:277-92. [6] Dunn JCY, Fonkalsrud EW. Improved survival of infants with omphalocele. Am J Surg 1997;173:284-7. [7] Alaish SM, Strauch ED. The use of Alloderm in the closure of giant omphalocele. J Pediatr Surg 2006;41:e37-9. [8] Kapfer SA, Keshen TH. The use of human acellular dermis in the operative management of giant omphalocele. J Pediatr Surg 2006;41: 216-20. [9] Hendrickson RJ, Partrick DA, Janik JS. Management of giant omphalocele in a premature low-birth-weight neonate utilizing a bedside sequential clamping technique without prosthesis. J Pediatr Surg 2003;38:e14-6. [10] Sanders S, Elicevek M, Unal M. Elastic bandaging facilitates primary closure of large ventral hernias due to giant omphaloceles. Pediatr Surg Int 2001;17:664-7. [11] DeLuca FG, Gilchrist BF, Paquette E, et al. External compression as initial management of giant omphaloceles. J Pediatr Surg 1996;31: 965-7.
A.E. Martin et al. [12] Lee SL, Beyer TD, Kim SS, et al. Initial nonoperative management and delayed closure for treatment of giant omphaloceles. J Pediatr Surg 2006;41:1846-9. [13] Bawazir OA, Wong A, Sigalet DL. Absorbable mesh and skin flaps or grafts in the management of ruptured giant omphalocele. J Pediatr Surg 2003;38:725-8. [14] DeUgarte DA, Asch MJ, Hedrick MH, et al. The use of tissue expanders in the closure of a giant omphalocele. J Pediatr Surg 2004; 39:613-5. [15] Bax NMA, van der Zee DC, Pull ter Gunne AJ, et al. Treatment of giant omphalocele by enlargement of the abdominal cavity with a tissue expander. J Pediatr Surg 1993;28:1181-4. [16] Foglia R, Kane A, Becker D, et al. Management of giant omphalocele with rapid creation of abdominal domain. J Pediatr Surg 2006;41: 704-9. [17] Livingston DH, Sharma PK, Glantz AI. Tissue expanders for abdominal wall reconstruction following severe trauma: technical note and case reports. J Trauma 1992;32:82-6. [18] Okumski WJ, Sonntag BV, Murphy RX. Staged reconstruction of abdominal wall defect after intra-abdominal catastrophes. Ann Plast Surg 1996;36:475-8. [19] Paletta CE, Huang DB, Dehghan K, et al. The use of tissue expanders in staged abdominal wall reconstruction. Ann Plast Surg 1999;42: 259-65.
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The use of intraabdominal tissue expanders as a primary strategy for closure of giant omphaloceles Abigail E. Martin, Adeel Khan, Daniel S. Kim, Christopher S. Muratore, Francois I. Luks ⁎ Division of Pediatric Surgery, Department of Surgery, Hasbro Children's Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA Received 3 October 2008; accepted 7 October 2008
Key words: Giant omphalocele; Abdominal wall defect; Tissue expanders
Abstract Background: Giant omphaloceles present a unique challenge to pediatric surgeons because of the difficulty in obtaining timely, tension-free closure of tissues over the defect. Reports of the use of tissue expanders in the subcutaneous space, intramuscular space, or intraabdominal cavity have illustrated the usefulness of this technique to provide biologic closure of abdominal wall defects. However, these reports have focused on use of tissue expanders as a second-line treatment after other options, such as silastic silos or attempted primary closure, have failed. Methods: We report 2 cases in which intraabdominal tissue expanders were used as a primary strategy to obtain closure of giant omphalocele defects. Case Reports: The first patient was a baby boy born at 36 weeks by date who was prenatally diagnosed with a giant omphalocele. An intraabdominal tissue expander was placed at 2 weeks of age. The tissue expander was removed and his abdomen was primarily closed at 8 weeks of age. The second patient was born at 25 weeks gestation as part of a twin gestation with severe intrauterine growth retardation (600 g birth weight). Bedside reduction was not attempted because of severe pulmonary hypertension and significant loss of abdominal domain because of herniated liver and bowel. At 8 months of age, she underwent laparoscopically assisted placement of an intraabdominal tissue expander. At 9 months of age, the tissue expander was removed, all abdominal viscera were reduced, and the defect was closed using only an 8 × 8-cm piece of AlloDerm (LifeCell, Branchburg, NJ). Both children are currently at home and doing well. Conclusions: We believe that early use of intraabdominal tissue expanders provides a more expedient method of obtaining closure of the defect in giant omphaloceles. © 2009 Elsevier Inc. All rights reserved.
An omphalocele is a congenital abdominal wall defect caused by failure of the cephalic, caudal, and lateral folds to fuse at the umbilical ring during the fourth week of gestation.
Presented at the 39th annual meeting of the American Pediatric Surgical Association, Phoenix, AZ, May 27-June 1, 2008. ⁎ Corresponding author. Tel.: +1 401 228 0556; fax: +1 401 444 6603. E-mail address: [email protected] (F.I. Luks). 0022-3468/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2008.10.031
Abdominal viscera, which can include intestine, colon, stomach, and liver, are covered by a peritoneal sac rather than normal abdominal wall musculature and the umbilical cord inserts at the apex of the sac. A giant omphalocele is defined as a defect that measures more than 6 cm and a sac that contains most of the of abdominal viscera including the liver, resulting in significant loss of abdominal domain and an underdeveloped peritoneal cavity [1]. Because of the large discrepancy between abdominal domain and the volume of
Intraabdominal tissue expanders to close grant omphaloceles extraabdominal organs, these defects present a significant challenge to pediatric surgeons. Potential pitfalls encountered when trying to return extraabdominal organs to the peritoneal domain include wound infections with or without the use of prosthetic materials to close the defect, compression of abdominal viscera or major intraabdominal vascular structures, and respiratory and cardiovascular compromise because of elevated diaphragms and high intraabdominal pressure [2-4]. Several approaches have been described to allow closure of giant omphaloceles. Creation of skin flaps to cover the defect, followed by later repair of the ventral hernia was initially described by Gross [5]. Gradual reduction of the viscera using a silo followed by delayed closure of the defect, with or without the use of prosthetic material, has become a popular approach to these defects [2,4,6-8]. Variations on this method include the use of elastic dressings on the sac to provide gradual pressure and reduction of the sac contents or sequential clamping of the sac without prosthetic material [9-11]. Epithelialization of the sac using topical agents followed by delayed closure of the defect has also been used [2,12]. Split-thickness skin grafting placed over absorbable mesh has also been described as a method to allow coverage of the defect until delayed closure of the ventral hernia can be attempted [13]. Tissue expanders placed in either the subcutaneous space or abdominal wall intramuscular spaces have been reported as a method to increase the size of potential skin or muscle flaps before closure [10,14]. Tissue expanders can also be placed intraperitoneally and gradually expanded to allow for
179 stretch of the abdominal wall and increase in abdominal domain. Reported cases in which intraabdominal tissue expanders have been used have focused on using this method after other attempts at reduction with either a silo or elastic compression dressings have failed [15,16]. We describe 2 patients in whom intraabdominal tissue expanders were used as the primary method to increase abdominal domain and allow for closure of the giant omphalocele defect.
1. Case reports 1.1. Case 1 The first patient was a baby boy born at 36 weeks gestation (birth weight, 2260 g). He had a giant omphalocele with approximately 75% of the liver and intestine visible within the intact sac (Fig. 1A). The sac was initially covered with sterile gauze while workup for other congenital abnormalities could proceed. He was found to have an atrial septal defect. Because of the size disproportion between the viscera within the sac and the abdominal cavity itself, traditional methods of reduction were not anticipated to be successful. Furthermore, because of the large proportion of the liver within the sac, methods that would compress the extraabdominal viscera risked compromising hepatic venous and caval return. After obtaining informed consent from the parents, an intraabdominal tissue expander was placed at day of life 19 (weight, 2610 g). A Pfannenstiel incision was made to allow placement of a saline tissue expander (10 by 13 cm,
Fig. 1 Case 1. A, Appearance of giant omphalocele shortly after birth. B, Infusion port of tissue expander seen exiting the right inquinal incision with omphalocele sac wrapped in Coban. C, Second operation showing closure of defect after excision of sac and removal of tissue expander. D, Patient at 7 months of age after closure of ventral hernia.
180 500 mL capacity) within the peritoneal cavity (PMT Corporation, Chanhassen, Minn). A right inquinal counterincision was created as an exit site for the inflation port that remained extracorporeal. The tissue expander was inflated with 50 mL of saline at the time of the initial operation. Over the next several weeks, the tissue expander was gradually inflated to a total volume of 180 mL and the omphalocele sac was dressed with gauze and Coban dressing (Fig. 1B). On day of life 41 (weight, 2860 g), the patient returned to the operating room for definitive repair of the defect. After taking down adhesions between the omphalocele sac and the liver and intestine, the sac was excised and the tissue expander was removed from the peritoneal cavity. The viscera were reduced, skin flaps were created, and the fascia was closed circumferentially leaving only a defect at the center measuring 2.5 by 2.5 cm (Fig. 1C). The skin was closed over this defect, and the patient recovered uneventfully. He returned to the operating room at 4 months of age for definite closure of the remaining ventral hernia. The patient had a good cosmetic result and is currently doing very well at 2 years of age (Fig. 1D).
1.2. Case 2 The second patient was a baby girl born as part of a twin gestation at 25 weeks with severe intrauterine growth retardation (birth weight, 600 g). She had bronchopulmonary dysplasia requiring tracheostomy, pulmonary hypertension, and a hemodynamically significant patent ductus arteriosus that eventually required ligation. Most of her liver and intestine were within the omphalocele sac. Because of her
A.E. Martin et al. severe pulmonary disease, no attempt was initially made to reduce the viscera, and the sac was instead covered with sterile dressings. By 8 months of age, the sac had completely epithelialized and her pulmonary status had stabilized. A computed tomographic scan clearly illustrated the extreme loss of abdominal domain, with volumetric analysis showing an approximate intraabdominal volume of 1500 mL and the extraabdominal viscera occupying approximately 2700 mL (Fig. 2A and B). She was taken to the operating room at 8 months of age (weight, 7430 g) where a saline tissue expander (15 by 15 cm, 1000 mL capacity; PMT Corporation) was placed using laparoscopic assistance. Initially, a suprapubic 12-mm trocar was placed to allow for laparoscopic inspection of the abdominal cavity and the defect. The tissue expander was introduced through the same incision and allowed to unfurl. A subcutaneous tunnel was created from the anterior left thigh, over the left inquinal ligament and in the peritoneal cavity through which the tubing used for inflating the tissue expander was passed. The infusion port was connected and placed in a subcutaneous pocket over the left anterior thigh. Postoperatively, the tissue expander was inflated to a volume of 120 mL and was gradually increased to a total volume of 1000 mL over the next month. At 9 months of age, the patient returned to the operating room for closure of the omphalocele defect. The abdominal cavity was entered through the omphalocele sac. The tissue expander was removed and the sac was excised (Fig. 2C). She tolerated full reduction of the viscera into the abdominal cavity, but the fascial defect was too large to close primarily and was closed using human acellular dermis (AlloDerm, LifeCell, Branchburg, NJ) (Fig. 2D). At
Fig. 2 Case 2. A, Sagittal view of computed tomographic scan of abdomen and pelvis illustrating most of the viscera in omphalocele sac. B, Three-dimensional reconstruction with volumetric analysis showing 2700 mL volume of extraabdominal viscera and 1500 mL volume of peritoneal cavity. C, Second operation showing excision of the sac and removal of the tissue expander. D, Closure of the fascial defect using AlloDerm.
Intraabdominal tissue expanders to close grant omphaloceles 19 months of age, she remains ventilator dependent and is tolerating feeds via a gastrostomy tube placed during her last surgery. She has not yet undergone final repair of her ventral hernia.
2. Discussion Treatment of giant omphaloceles has remained a challenge for pediatric surgeons despite advances in neonatal medicine. Most traditional methods of treating giant omphaloceles have concentrated on allowing coverage of the defect with a resulting large ventral hernia to be repaired later in life. These approaches take into account the fact that many patients with giant omphaloceles have associated pulmonary hypoplasia and ventilator dependence in which increases in intraabdominal pressure could significantly impair ventilation. Other approaches have used either external compression or gravity itself to reduce the viscera into the abdominal cavity. However, these methods risk ischemic damage to the organs themselves or to other intraabdominal vascular structures. The ideal approach to giant omphaloceles would emphasize decreasing the disproportion between the volume of extraabdominal viscera and intraperitoneal space. Because the viscera cannot become less voluminous, increasing intraperitoneal space becomes the goal and tissue expanders offer the ideal solution to this problem. Subcutaneously placed tissue expanders have been successfully used in other surgical situations in which creation of abdominal wall skin was necessary, including adult patients who had loss of the abdominal wall from either traumatic or infectious events [17,18]. Similarly, tissue expanders have been used to increase the amount of abdominal wall skin in pediatric patients with abdominal wall defects [10,19]. De Ugarte et al [14] presented a novel approach to using tissue expanders placed within the intramuscularly layers of the abdominal wall of a patient with a giant omphalocele, allowing creation of an outer layer composed of skin and internal and external oblique muscles. However, placement of a silo was still necessary to allow reduction of the viscera before the skin and muscle flaps could be closed over the defect. Intraabdominal placement of tissue expanders offers the advantage of creating “tissue flaps” that include all layers of the abdominal wall, including skin, muscle, and peritoneum. This method has already been successfully described in the literature by at least 2 centers. Bax et al [15] described using the tissue expander in a term neonate whose omphalocele defect was small, but most of the liver was in the sac, preventing any compressive type of strategy to reduce the viscera. Foglia et al [16] used intraabdominal tissue expanders in 2 patients, one a neonate with a giant omphalocele in whom silo reduction had failed and one in a 4-year-old girl with a giant omphalocele that had been allowed to epithelialize but had never been repaired because
181 of associated congenital anomalies. Because of the success of intraabdominal tissue expanders in these cases, we used this method as a first-line strategy in the 2 patients presented in this report. Our first patient was a near-term neonate with a giant omphalocele not believed to be amenable to more traditional approaches. We opted against using any type of silo or other compressive method, and instead placed the intraabdominal tissue expander as a primary strategy to increase peritoneal domain. During his second operation, the resulting ventral defect only measured 2.5 by 2.5 cm and did not require placement of any type of graft. The small size of the defect also allowed repair at 4 months of age as an outpatient procedure. We believe the size of his ventral hernia compares very favorably with the larger size ventral hernias that can result from other approaches. Our second patient was a very premature neonate born at 25 weeks gestation with significant comorbidities preventing safe reduction of her extraabdominal viscera by any means. Ultimately, AlloDerm was used to close her fascial defect, but the eventual defect was significantly smaller than would have existed without prior use of the tissue expander. The 2 patients presented in this report illustrate the efficacy and safety of intraabdominal tissue expanders as a means to increase intraabdominal domain in preparation for repair of giant omphaloceles. Initial placement of these devices should do little to affect intraabdominal pressure, but care must be taken over the ensuing days and weeks as the volume within the tissue expanders is increased to avoid any respiratory compromise or visceral ischemia. We cannot report any adverse effects of gradual inflation of the tissue expander, but close monitoring of patients for signs of abdominal compartment syndrome is imperative. Disruption of the omphalocele sac could potentially result from inflation of a tissue expander, although we did not experience this complication in our patients nor did we find reports of this in the literature. Inflation of the tissue expanders should distribute the pressure equally over the abdominal wall tissues and the sac, and by increasing the volume gradually, acute disruption of the sac is very unlikely. The ultimate choice in how to approach such a complex problem as giant omphalocele must be left up to the pediatric surgeon's best judgment. We believe that judicious, early use of intraabdominal tissue expanders can provide a more expedient method of obtaining closure of the defect in giant omphaloceles.
References [1] Minkes RK. Abdominal wall defects. In: Oldham KT, Colombani PM, Foglia RP, et al, editors. Principles and practice of pediatric surgery. Philadelphia (Pa): Lippincott, Williams, and Wilkins; 2005. p. 1103-19. [2] Nuchtern JG, Baxter R, Hatch Jr EL. Nonoperative initial management versus silo chimney for treatment of giant omphalocele. J Pediatr Surg 1995;30:771-6.
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