Nutritional and pharmacological strategy in children with short bowel syndrome.

Short bowel syndrome in neonates is a severe and life-threatening disease after a major loss of small bowel with or without large bowel. Intestinal adaptation, by which the organism tries to restore digestive and absorptive capacities, is entirely dependent on stimulation of the active enterocytes by enteral nutrition. This review summarizes recent knowledge about the pathophysiologic consequences after the loss of different intestinal parts and outlines the options for enteral nutrition and pharmacological therapies to support the adaptation process.

Surgical strategies in short bowel syndrome.

Extensive loss of small bowel in all age groups has significant morbidity and mortality consequences. Despite the astonishing ability of the small bowel to compensate for an extensive loss, long-term parenteral nutrition and enteral nutrition, tailored to the need of the patients in relation to the missing intestinal regions is needed. Organ-preserving surgical intervention becomes necessary in patients with a very short intestinal transit time and in an other group of patients with impaired propulsive peristalsis. Intestinal transplantation is indicated in recurrent septical infections or if nearly all of the small bowel is missing. This review discusses indications and risks of the organ-preserving surgical therapies in children with short bowel syndrome.

Long-term results of total colonic agangliosis patients treated by preservation of the aganglionic right hemicolon and the ileo-cecal valve.

PURPOSE: In 1989, Sauer introduced a technique to treat patients with total colonic aganglionosis (TCA) where he preserved the ileo-cecal valve and the right hemicolon to retain water and electrolyte absorption. This report examines the long-term outcome of patients who underwent this technique. METHODS: All TCA patients treated between 1981 and 2005 according to Sauer were invited in 2013 to participate in a questionnaire survey to assess their long-term outcome focusing on bowel function and quality of life (QoL), using standardized scores. RESULTS: Of eight TCA patients (2 females, 6 males), seven participated in the follow-up survey (median follow-up time 13.5 years (range 8-31.6). Early postoperative complications involving bouts of enterocolitis in 3 and anal strictures in 5 patients ceased with age. Bowel movements ranged from median 3-4 times a day (range 1-8). Bowel-function score (BFS) was reduced in 6 patients (median 16 points, range 8-19, max 20), who also reported soiling incidences with the need for night-time protective aids in two. QoL assessment, however, documented a good outcome with a median score of 10 points (range 7-13, max 13). CONCLUSION: This long-term investigation of TCA patients treated according to Sauer's technique documented a good QoL despite a reduced BFS.

Gastroschisis-related complications requiring further surgical interventions.

PURPOSE: The aim of this study was to determine the incidence of gastroschisis-related complications (GRCs) after closure of the abdominal wall defect, with a focus on frequency, type and timing of required surgical interventions, and to identify the impact of these on further outcome. METHODS: All gastroschisis patients treated from 1975 to 2008 in a tertiary-level center were retrospectively reviewed. Surgical procedures for GRCs following abdominal wall closure of simple gastroschisis [SG (intact continuous bowel)] and complex gastroschisis [CG (additional gastrointestinal malformations)] were compared, and outcomes were determined. RESULTS: One hundred and eight patients were identified with a median follow-up of 15.0 years (range 4-37). Ninety-four (87%) had SG, and 14 (13%) CG. Surgical interventions for GRCs were performed in 28 (26%) patients with 16 requiring multiple operations. Overall, 60 surgical procedures were performed. Bowel obstruction (n = 34) was the most common GRC, followed by anastomotic stricture (n = 8) and ischemic bowel (n = 3). The median interval between gastroschisis closure and secondary surgery for GRCs was 62.5 days (range 1 day-15 years). Surgical interventions were significantly more frequent in CG compared with SG [12/14 (86%) vs. 16/94 (17%); P < 0.0001]. The overall survival rate was 90%. Significantly, more patients required parenteral nutrition for more than 28 days [9/28 (32%) vs. 13/80 (16 %); P = 0.0468], longer median time to achieve full enteral feedings (87 vs. 33 days; P < 0.0001) and longer median hospital stay (117 vs. 54 days; P < 0.0001) compared with those not requiring additional surgery. CONCLUSION: GRCs requiring surgical interventions were more common in patients with CG, which were associated with delay in achieving full enteral feedings and prolonged hospital stay.

Proton pump inhibitors for reflux therapy in infants: effectiveness determined by impedance pH monitoring.

PURPOSE: To evaluate the influence of proton pump inhibitors (PPI) in predominantly milk-fed infants with symptoms of GERD by 24-h pH-multichannel intraluminal impedance (24-h pH-MII). METHODS: Ten infants (8 males and 2 females) with a mean gestational age of 39 weeks (28-40) were included. 24-h pH-MII was performed before prescription and during intake of PPI. Total acid exposure time, bolus exposure time (acidic/non-acidic/total) and the number of refluxes (acidic/non-acidic/total) were determined. Clinical symptoms were recorded and used to calculate the Reflux Symptom Index (RSI) and the Symptom Severity Index (SSI). RESULTS: There was a significant decrease in the number of acidic refluxes, total acid exposure and acidic bolus exposure time. However, this went along with a significant increase in non-acidic bolus exposure time. The total number of refluxes and the total bolus exposure time remained unchanged. Under PPI, a decrease of SSI and RSI for pain-related symptoms could be observed. For respiratory symptoms and vomiting however no significant changes could be demonstrated. CONCLUSIONS: Under PPI, an improvement of pain-related symptoms could be shown. The decrease of acid exposure went along with an increase of non-acidic refluxes resulting in almost constant total reflux numbers. This finding is interpreted as main reason for some persisting symptoms despite adequate PPI dosage. Concluding from our data PPI therapy should only be indicated in case of pain, but has no effect in case of vomiting or recurrent respiratory symptoms.

Pre- and postoperative rectal manometric assessment of patients with anorectal malformations: should we preserve the fistula?

BACKGROUND: Surgical correction of congenital anorectal malformations could be complicated by fecal incontinence. Some authors believe that preservation of the fistula is associated with improved outcome. Rectal manometry is a well-established method to evaluate postoperative functional outcome in these patients and can demonstrate successful transplantation of the fistula. OBJECTIVE: Herein, we report the results of our series of patients with anorectal malformations and an externally accessible fistula, who underwent pre- and postoperative rectal manometry studies. DESIGN: This is a prospective cohort study. SETTINGS: This study was conducted at a tertiary neonatal and pediatric surgical center. PATIENTS: Patients with anorectal malformations, who underwent preoperative rectal manometry of the fistula and postoperative rectal manometry of the neoanus between January 2002 and December 2011 were included. MAIN OUTCOME MEASURES: Pre- and postoperative rectal manometry results were compared by using paired t test or contingency tables (p values <0.05). RESULTS: Twelve female patients with rectoperineal (n = 7, 58%) or rectovestibular (n = 5, 42%) fistula were treated by anterior sagittal anorectoplasty or minimal posterior sagittal anorectoplasty. Complete transposition of the fistula was achieved in all patients. Normal presence of rectoanal inhibitory reflex was demonstrated in all pre- and postoperative rectal manometry studies. There were no differences between pre- and postoperative rectal manometry in the length of the high-pressure zone (2.3 ± 0.6 cm vs 2.5 ± 0.8 cm (p = 0.5)) and resting pressure (59.4 ± 18.2 mm Hg vs 62.1 ± 19.2 mm Hg (p = 0.62)). At a median follow-up of 665 days (range, 290-1165 days), all patients have voluntary bowel movements, with no incontinence or soiling. LIMITATIONS: This study is limited by its small sample size and by single-institution bias. CONCLUSION: Preoperative rectal manometry of rectoperineal or rectovestibular fistula showed the presence of functional anal structures within the fistula in all patients. We speculate that fistula-preserving surgery in patients with anorectal malformations is associated with improved bowel function outcome.

Outcomes after interdisciplinary management of 7 patients with Askin tumor.

PURPOSE: Askin tumors are rare but highly malignant chest wall tumors, which require multimodal therapy including often extensive resection of the thoracic wall. This study evaluated the outcome of Askin tumor in seven patients with an interdisciplinary approach. METHODS: Patients' records, treated between 1994 and 2011, were reviewed retrospectively. Seven patients (three male, four female; mean age 12.3 years; range 2-21 years) were included. All patients received neoadjuvant chemotherapy. After reduction of initial tumor volume, radical tumor resection and thoracic wall reconstruction were performed. All survivors were evaluated in 2011 by clinical examination and lung function test. RESULTS: Five-year survival rate in our group of patients is 86 % and overall survival is 71 %. There were two mortalities. One patient passed away 7.5 years after the primary management, mainly attributed to tumor progression, which demanded aggressive surgical procedures and irradiation. Another patient died 18 months after the first diagnosis after several surgical interventions for recurrent multiple pulmonary metastases. Three years after the first diagnosis, one patient suffered from clear cell sarcoma of the contralateral kidney and developed a local recurrence of Askin 1 year later. The large chest wall defects arising after surgery have been successfully reconstructed using combination of latissimus dorsi muscle flaps and biomaterials. CONCLUSION: Data of pediatric patients with Askin tumor is scarce. Analysis of our seven patient series indicates that improved outcomes (71 % over all survival rate and 86 % 5-year survival rate) can be achieved by aggressive interdisciplinary management including radical surgery and chemotherapy. Chest wall stability can be achieved by utilization of local muscle flaps and biomaterials to cover surgical chest wall defects.

The 100 most-cited articles in Pediatric Surgery International.

PURPOSE: Citation analysis within specific journals and subject areas has become a popular method to assess the impact of a journal, article or author. To date, only a few evaluations of citation reports have been published in the field of pediatric surgery. Twenty-six years after its inception, Pediatric Surgery International (PSI) is a firmly established journal in pediatric surgery. The aim of this study was to identify, analyze and categorize the characteristics of the 100 most-cited articles published in PSI since its founding in 1986. METHODS: The Web of Knowledge(SM), hosted by the Institute for Scientific Information, was searched with the all-database function for the 100 most-cited articles in PSI published from 1986 to the present. Each article was reviewed and the following parameters were recorded: number of citations, type of article, topic, year of publication, country of origin, institution and authorship. RESULTS: Between 1986 and 2012, 4,907 articles were published in PSI and 3,608 (73.53 %) of these were cited at least once. The 100 most-cited articles received a total of 3,309 citations with a mean of 33.09 (range 24-81). These articles were published between 1987 and 2007, with 73 articles published after 1997. Leading countries were USA (n = 15), Australia (n = 12), UK (n = 9) and Ireland (n = 9). Articles were categorized as followed: 92 original articles, 5 reviews and 3 case reports. 84 articles derived from clinical research and 16 derived from basic science. The most prolific authors were from 7 different institutions and published 37 articles, which received 1,213 (36.66 %) citations. CONCLUSION: The 100 most-cited articles published in PSI were predominately original articles from English-speaking countries dealing with clinical topics. This analysis may be of value to the editorial board and authors by providing some insights into what types of manuscripts appear to be of interest to the reading audience of PSI.

Trends in the treatment and outcome of congenital diaphragmatic hernia over the last decade.

PURPOSE: Congenital diaphragmatic hernia (CDH) remains a challenging and life-threatening congenital anomaly. The aim was to evaluate whether treatment and survival has changed during the last decade. METHODS: We retrospectively analysed all consecutive infants with CDH referred to two European tertiary paediatric surgical centres over 11 years (January 1999 to December 2009). Minimum follow-up was 1 year. χ(2) test for trend was used to evaluate significance. RESULTS: There were 234 infants. There was no significant variation over time in the proportion of infants receiving high frequency oscillatory ventilation (HFOV) (p = 0.89), inhaled nitric oxide (iNO) (p = 0.90) or extracorporeal membrane oxygenation (ECMO) (p = 0.22). 205 infants (88 %) were stabilised and underwent surgical repair; of these, 186 (79 %) survived after surgery. Over time there was a significant increase in the proportion of infants undergoing surgical repair (p = 0.018) without a concomitant significant improvement in survival (p = 0.099). CONCLUSION: This multicentre analysis indicates that the survival rate of infants with CDH referred to two European paediatric surgical centres is high (79 %). The use of HFOV, iNO and ECMO has not changed in recent years. We observed a significant increase in the proportion of infants who undergo surgery but this has not resulted in a significant increase in the overall survival rate.

Management of isolated and associated colonic atresia.

PURPOSE: Colonic atresia is a rare cause of congenital intestinal obstruction in the neonate. A review of the management and outcome of children with colonic atresia was performed. METHODS: A retrospective analysis of the complete records of children treated for colonic atresia during the 30-year period. RESULTS: A total of 14 newborns were treated. Seven infants suffered from an isolated colonic atresia (group 1). In the other seven infants (group 2), colonic atresia was either associated with additional intestinal atresias (n = 2), or gastroschisis (n = 5). Gestational age and birth weight were significantly lower in infants from group 2 compared to group 1 (40 ± 0.5 vs. 37 ± 1 weeks (P < 0.05); and 3,478 ± 208 vs. 2,626 ± 242 g (P < 0.01), respectively). The first surgical procedure was performed in all newborns within 24 h after birth. All but one infant from group 1 received primary colostomies at the level of colonic atresia, followed by end-to-side anastomoses. All but one infant from group 2 needed ileocoecal resection due to bowel necrosis. No child died in group 1, whereas three children died in group 2. CONCLUSIONS: Isolated colonic atresia is amenable with a short hospital stay and an excellent outcome. In contrast, infants with colonic atresia associated with gastroschisis present a serious clinical challenge.

Pre-pubertal presentation of peritoneal inclusion cyst associated with congenital lower extremity venous valve agenesis.

Peritoneal inclusion cysts are uncommon lesions that usually occur in the pelvis of reproductive-age females. The case of a 7-year-old girl with an inflamed peritoneal inclusion cyst with unusual right paracolic localization and congenital lower extremity superficial and deep venous valve agenesis is presented. Inflammation of the peritoneal inclusion cyst was responsible for the signs of acute abdomen and subsequent presentation at our center. The cystic structure was initially diagnosed using ultrasonography, and its complete extent (8cm x 6.5cm x 4cm) was evident after magnetic resonance imaging. The minimal access approach was opted for to resect the entire cyst from the lateral border of the ascending colon. Afterwards, the cyst was punctured to reduce its size and to retrieve the cyst wall using an endoscopic specimen retrieval bag. Minimal access surgery precautions in this patient with congenital lower extremity venous valve agenesis are discussed.

Fluorescence-activated cell sorting of PCK-26 antigen-positive cells enables selection of ovine esophageal epithelial cells with improved viability on scaffolds for esophagus tissue engineering.

OBJECTIVE: For esophagus tissue engineering, isolation and proliferation of esophageal epithelial cells (EEC) is a pre-requisite for scaffold seeding to create constructs. The aim of this study was to sort EEC expressing cytokeratin markers and their proliferative subpopulations; also, to investigate the viability of differentiated EEC subpopulations on collagen scaffolds. METHODS: Ovine esophageal epithelial cells (OEECs) from sheep esophagus were analyzed using flow cytometry for pan cytokeratin (PCK-26) and proliferation cell nuclear antigen (PCNA). Using fluorescent-activated cell sorting, OEEC were separated and analyzed for PCNA expression. The OEEC subpopulations were seeded on collagen scaffolds for a week in vitro culture. RESULTS: Proliferation cell nuclear antigen was expressed in >45% of OEEC isolated. In flow cytometry, 30% OEEC were PCK-26 positive which exhibited a high-proliferative capacity of 80%. PCK-26-negative OECC exhibited a low-proliferative capability of 13%. Scanning electron microscopy demonstrated organized attachment and uniform scaffold coverage in PCK-26-positive cells. CONCLUSION: Ovine esophageal epithelial cells can be divided into PCK-26-positive and negative subpopulations. PCK-26-positive OEEC constitute one-third of the isolated cells with high-proliferative capability. Seeding of PCK-26-positive OEEC on collagen scaffolds leads to uniform distribution of cells in vitro. In esophagus, tissue engineering PCK-26-positive OEEC subpopulation is important for optimal construct generation.

Trampoline-related injuries in childhood.

Recommendations to prevent trampoline injuries were given since the 1970s. However, despite these educational efforts, safety recommendations seem to be ignored and the number of trampoline injuries is increasing. All children referred to our department for injuries related to trampolines over a period of 3 years were included. The patients' records were reviewed and a questionnaire was sent out in order to gain additional information. Injuries were classified as severe and mild. A total of 265 children (46% m, 54% f) with a median age of 8.2 years (range 1 to 14) were included. The injury rate was continuously growing from the year 2005 (10.6%) to 2007 (58.1%). Most of the injuries were recorded between April and September with a peak of injuries in August. Seventy-five percent of all accidents happened in the afternoon; 40% of the injuries were classified as severe, 60% as mild. Nets or equal security devices were used in 56.6%. Trampolining is associated with a significant risk for bodily harm at any age and results in severe injuries in 40% of cases. Though there may be still room for improvement in safety recommendations, all attempts over a period of more than 30 years to reduce the number of trampoline-related backyard injuries failed and the incidence is still increasing. At present, trampolines cannot be made safe for recreational activities and are of an unacceptable risk even under supervision.

Postoperative Complications and Functional Outcome after Esophageal Atresia Repair: Results from Longitudinal Single-Center Follow-Up.

BACKGROUND: Esophageal atresia (EA) and tracheoesophageal fistula (TEF) represent major therapeutic challenges, frequently associated with serious morbidities following surgical repair. The aim of this longitudinal study was to assess temporal changes in morbidity and mortality of patients with EA/TEF treated in a tertiary-level center, focusing on postoperative complications and their impact on long-term gastroesophageal function. METHODS: One hundred nine consecutive patients with EA/TEF born between 1975 and 2011 were followed for a median of 9.6 years (range, 3-27 years). Comparative statistics were used to evaluate temporal changes between an early (1975-1989) and late (1990-2011) study period. RESULTS: Gross types of EA were A (n = 6), B (n = 5), C (n = 89), D (n = 7), and E (n = 2). Seventy (64.2%) patients had coexisting anomalies, 13 (11.9%) of whom died before EA correction was completed. In the remaining 96 infants, surgical repair was primary (n = 66) or delayed (n = 25) anastomosis, closure of TEF in EA type E (n = 2), and esophageal replacement with colon interposition (n=2) or gastric transposition (n=1). Long-gap EA was diagnosed in 23 (24.0%) cases. Postoperative mortality was 4/96 (4.2%). Overall survival increased significantly between the two study periods (42/55 vs. 50/54; P = 0.03). Sixty-nine (71.9%) patients presented postoperatively with anastomotic strictures requiring a median of 3 (range, 1-15) dilatations. Revisional surgery was required for anastomotic leakage (n = 5), recurrent TEF with (n = 1) or without (n=9) anastomotic stricture, undetected proximal TEF (n = 4), and refractory anastomotic strictures with (n = 1) or without (n = 2) fistula. Normal dietary intake was achieved in 89 (96.7%) patients, while 3 (3.3%) remained dependent on gastrostomy feedings. Manometry showed esophageal dysmotility in 78 (84.8%) infants at 1 year of age, increasing to 100% at 10-year follow-up. Fifty-six (60.9%) patients suffered from dysphagia with need for endoscopic foreign body removal in 12 (13.0%) cases. Anti-reflux medication was required in 43 (46.7%) children and 30 (32.6%) underwent fundoplication. The rate of gastroesophageal reflux increased significantly between the two study periods (29/42 vs. 44/50; P = 0.04). Twenty-two (23.9%) cases of endoscopic esophagitis and one Barrett's esophagus were identified. CONCLUSIONS: Postoperative complications after EA/TEF repair are common and should be expertly managed to reduce the risk of long-term morbidity. Regular multidisciplinary surveillance with transitional care into adulthood is recommended in all patients with EA/TEF.

[Treatment of medial epicondylar apophyseal avulsion injury in children].

OBJECTIVE: Surgical reduction and retention of apophyseal avulsion injuries at the medial epicondyle to prevent joint instability, lasting malalignment, or pseudarthrosis. INDICATIONS: Absolute: intraarticular apophyseal dislocation of the medial epicondyle, complete lesion of the ulnar nerve. Relative: dislocation of the apophysis (> 4 mm) in children > 5 years of age; the need for intervention increases in children as the degree of dislocation, age, and athletic activity increase. CONTRAINDICATIONS: Dislocation of the medial epicondyle (< or = 4 mm) in children < 5 years of age, provided the fragment location is not intraarticular. SURGICAL TECHNIQUE: Open reduction of the apophysis through a medial approach. Identification of the ulnar nerve. In young children or with small fragments fixation with Kirschner wire. Screw fixation in older children or for larger fragments. POSTOPERATIVE MANAGEMENT: Long upper-arm plaster cast until wound healing is achieved. Subsequently, upper-arm plaster cast for 3 weeks. Removal of Kirschner wires after 4-6 weeks, screw removal after 8-12 weeks. Physiotherapy only if marked reduction of elbow mobility is found 6 weeks after cast removal. RESULTS: From January 1, 1994 to December 31, 2003, 25 children with an average age of 12 years suffering from medial epicondylar avulsion fractures were operated on using open reduction and Kirschner wire fixation. An average of 3 years after the injury 14 of these children underwent follow-up examination using a procedure that took subjective, clinical and radiologic parameters into account. Two children showed a slight reduction in overall strength of the injured extremity when compared with the contralateral extremity. One child had a flexion deficit of 10 degrees, all other children showed movement limitations of < or = 5 degrees compared to the contralateral extremity. In all the cases available to follow-up, there was a slight increase in valgus alignment of the elbow joint compared with the uninjured side (3 degrees on average). All fractures consolidated within 6 weeks.

Straddle injuries in female children and adolescents: 10-year accident and management analysis.

OBJECTIVE: To analyze unintentional straddle injuries in girls with regards to epidemiology, etiology and injury management. METHODS: The hospital database was retrospectively reviewed (1999-2009) for female patients managed for genital trauma. Patients were evaluated based on age, causative factors, type of injury, area of genitals affected, management and outcomes. RESULTS: Straddle injuries were documented in 91 girls with age ranging from 1 to 15 y (mean = 6.3 y; median = 6.1 y). The causes of injuries were falls at home (n = 31) or outdoors (n = 27), and sport activities (swimming pool n = 11, skating n = 11, bicycle n = 9 and scooter n = 2). Most of the injuries were lacerations. Injuries involved major labia (n = 56), minor labia (n = 45) and introitus vaginae (n = 15). Twelve children received outpatient treatment. Inspection under anesthesia was performed in 79 patients, with 76 requiring sutures. While hematuria was observed in 18 patients, cystoscopy did not reveal lesions in the urethra or bladder. Associated injuries were femur fracture (n = 1), lower extremity lacerations (n = 4) and anal lesions (n = 2). Follow-up investigations were uneventful; however one patient developed a secondary abscess and another secondary hyperplasia of the labia minor. CONCLUSIONS: Falls and sports are major causes of straddle injuries with a peak at the age of six years. Lacerations are the most common injuries and often require surgical management. Urinary tract injuries and other associated injuries are relatively uncommon in girls with straddle injuries.

Closure of bronchopleural fistula with porcine dermal collagen and fibrin glue in an infant.

The management of an 11-month-old infant who developed a bronchopleural fistula (BPF) 3 weeks after video-assisted thoracic surgery for congenital cystic adenomatoid malformation of the right lower pulmonary lobe is presented. Being refractory to treatment with chest tubes, the BPF was managed using a bronchoscopic approach using porcine dermal collagen (PDC) combined with a fibrin glue plug. The single session was sufficient to manage the BPF and the postoperative course was uneventful. This case highlights the novelty in the successful management of BPF in infants after pulmonary surgery using PDC and fibrin glue using the minimal access bronchoscopic approach.

The impact of preoperative ultrasound on correct diagnosis of urachal remnants in children.

BACKGROUND: Ultrasound is a noninvasive imaging method used widely in urachal diagnostics. This study investigated the effectiveness of ultrasonography in correctly depicting urachal anomalies in children. METHODS: Preoperative ultrasound findings of all patients who were operated on for suspected urachal anomalies between 1990 and 2008 were retrospectively compared with the final diagnosis. RESULTS: Fifty-three patients (31 female, 22 male; approximately 2.6 years; range, 0-17 years) were reviewed. In 37 patients, the final diagnosis of an urachal anomaly matched the ultrasound findings. In 7 patients, there was a false-positive ultrasound finding, and in 9 patients, there was a false-negative ultrasound finding. Three of 4 patients with urachal cysts, 23 of 29 patients with urachal fistulas, and 8 of 10 patients with urachal sinuses were correctly identified by ultrasonography. In 10 patients, no urachal rests were found intraoperatively: in 7 of these patients, urachal rests were falsely suspected by ultrasound. The positive predictive value for ultrasound is 83%, whereas the negative predictive value is 25%. The sensitivity for this diagnostic method is 79% and the specificity 30%. CONCLUSIONS: Ultrasound helps to identify urachal anomalies in case of their presence but is not helpful to rule out a nonexisting urachal anomaly.

Culture of ovine esophageal epithelial cells and in vitro esophagus tissue engineering.

BACKGROUND: Esophagus replacement presents major surgical challenges both in the pediatric and in adult patients since the various surgical techniques presently employed are associated with complications and high morbidity. AIM: The aim of this study was to establish protocols for isolation and culture of ovine esophageal epithelial cells (OEEC) and to investigate their viability on collagen scaffolds for in vitro tissue engineering. METHODS: OEEC were sourced from adult Austrian mountain sheep. Briefly, the esophagus was dissected, treated with dispase to separate the epithelial layer, and further subjected to a modified explants technique to isolate OEEC. The OEEC were cultured in vitro and seeded on to unidirectional two-dimensional and three-dimensional collagen scaffolds. RESULTS: Successful protocol was established for OEEC isolation and culture. OEEC exhibited organization and differentiation after 7 days in culture, which was complete after 18 days with the formation of a single layer sheet of differentiated cells exhibiting morphology of mature esophageal epithelium. OEEC seeded on two-dimensional collagen scaffolds demonstrated viability up to 6 weeks of in vitro culture with single layer epithelium formation after 3 weeks confirmed using pan-Cytokeratin markers. OEEC on three-dimensional scaffolds were viable for 6 weeks but did not form an epithelium sheet. CONCLUSION: Protocols for OEEC isolation were developed and established from adult ovine esophageal tissue. The generation of sheets of esophageal epithelium in culture and the viability of OEEC on collagen scaffolds for 6 weeks in vitro was observed. The prerequisite for esophagus tissue engineering, which is the ability to form epithelium when seeded on collagen scaffolds, was demonstrated.

Comparison of suturing techniques in the formation of collagen scaffold tubes for composite tubular organ tissue engineering.

In order to construct tubes for tissue engineering of composite tubular organs in the gastrointestinal tract, suturing techniques were investigated with regards to (a) type of suture material, (b) state of scaffold, (c) technical variations and (d) changes in scaffold morphology. Collagen scaffolds of 13 mm diameter and 3 mm thickness, in both dry and wet states, were sutured using braided and monofilament sutures. Four suture techniques were employed (a) continuous loop, (b) interrupted loops, (c) interrupted edge sutures and (d) continuous running edge suture. Scanning electron microscopic imaging was performed on the 4 tubes sutured. Monofilament sutures were used for tube formation as braided sutures were unsuitable. Dry scaffolds demonstrated tears during knot tying and fractures when bent around a stent. The interrupted and continuous running edge suture were the most suitable suturing techniques in wet scaffolds; further confirmed by scanning electron microscopy imaging. Our approach to tissue engineer segments of the gastrointestinal tract involves cell-seeding on scaffolds to permit attachment in vitro and later wrapping of scaffold layers of heterogeneous cells to create composite tissue. Scaffolds in wet state can be better sutured with monofilament materials using either the interrupted or running continuous edge suture technique.