Current Studies

Collaborative research in action—improving surgical care, one study at a time.

The Midwest Pediatric Surgery Research Consortium is currently conducting multi-institutional studies focused on high-impact pediatric surgical conditions. These active projects bring together the expertise of our 11 member hospitals to generate meaningful data, improve outcomes, and guide best practices in the surgical care of children.

Esophageal Atresia/Tracheoesophageal Fistula

Esophageal Atresia/Tracheoesophageal Fistula (EA/TEF) occurs in approximately 1/3500 live births. The MWPSC Centers identified variability in surgical techniques and management of infants with EA/TEF due to the lack of evidence-based guidelines. This was the first disease studied with the consortium. In 2016, Lal et al. published the largest multi-institutional retrospective analysis of 396 patients to define and understand current management practices. Their findings included an overall postoperative complication rate of 62%, anastomotic stricture rate of 42% and substantial practice variability amongst the participating centers.
In 2017, Lal et al. expanded on the previous study and examined specific peri-operative management features in patients with type-c defects, searching for modifiable factors associated with the high complication rates found in their previous study. It was shocking to the authors that the overall complication rates for patients with EA/TEF had not improved in decades, despite advances in technology and surgical technique. The authors reported the use of trans-anastomotic tubes in the post-operative setting were associated with increased rates of anastomotic stricture (OR 2.2, p=0.01), interposing prosthetic material between the trachea and esophageal suture line was associated with higher anastomotic leak rates (OR 4.7, p<0.001). Furthermore, common practices such as the use of prophylactic antibiotics greater than 24 hours or empiric acid suppression did not prevent complications. Lastly, obtaining post-operative esophagrams on day 5 instead of the traditional day 7, was safe and resulted in earlier initiation of feedings.

The identified risk factors in the 2017 paper, led to the creation of evidence-based clinical practice guidelines to standardize management amongst institutions within the consortium. The outcomes from this intervention were published in a 2020 paper by Bence et al. A standard management bundle was applied to 102 infants with type c-defects and compared to a historical control of 68 infants. The key components of the management bundle were no prosthetic material between esophageal and tracheal sutures, no routine trans-anastomotic tube, no prophylactic antibiotics past 24 hours, and performing esophagrams within 5 postoperative days. The authors demonstrated no increase in complications keeping prophylactic antibiotics to only 24 hours and performing an esophogram at day 5 instead of day 7 from surgery. Additionally, when compliance to the no prosthetic material and no trans-anastomotic tube was >80% there was a reduction in anastomotic strictures.

Two other special populations of EA/TEF have been studied through the MWPSC: patients with right-sided aortic arch (RAA), and those with type E (H-type) TEF. Lal et al. reported findings from one of the largest studies on neonates with EA and RAA. When compared to infants with EA and a left aortic arch, infants with EA and a RAA were more severely ill with lower birth weight and higher rates of prematurity and complex congenital heart disease. They found that EA repair in infants with RAA can be safely repaired through a right or left thoracotomy. However, there was a trend to higher anastomotic strictures in RAA patients who underwent EA repair via a right thoracotomy. From the initial study on perioperative outcomes in EA patients, a high rate of vocal cord paralysis/paresis (5-28%) was identified and varied by EA/TEF type. This data led to a subsequent MWPSC proof of concept study by Wright et al. in which intraoperative nerve monitoring was used to identify, stimulate and preserve the recurrent laryngeal nerve during fistula ligation in infants with Type E (H-type) TEF. EA/TEF remains an active area of research amongst the consortium. The goal is to improve the care and outcomes of infants undergoing EA/TEF repair through evidence-based practices and standardization of care.

Giant Omphalocele

Giant omphalocele is a rare condition that results in a large defect (>5 cm), in the abdominal wall through which the abdominal contents migrate. In most giant omphaloceles, at least 50% of the liver is present in the omphalocele sac outside of the abdominal cavity. Management of giant omphaloceles has challenged pediatric surgeons but no “gold standard” treatment exists. The MWPSC is currently enrolling subjects in a prospective study of the use of an external compression silo that is applied in the NICU and is used to slowly reduce the contents back into the abdominal cavity without multiple surgical interventions or prolonged intubation/sedation. This study has been enrolling patients since 2022. A separate retrospective study looking at the contemporary management of giant omphalocele in our centers was conducted concurrently and is currently in the process of being published.

Management of Spontaneous Pneumothorax

Primary Spontaneous Pneumothorax (PSP) occurs in up to 1 in 6000 males and 1 in 16,000 females. The etiology is thought to be from rupture of thin-walled blebs or bubbles in the lungs and presents with sharp pain on the affected side. Depending on size and symptoms, there are many ways of managing this but traditionally, it has been done with a chest tube to suction out the air and let the lung re-expand. There have been several adult studies that have shown the majority of these resolved without intervention if the pneumothorax did not expand under a period of observation. The MWPSC sought to examine whether simple aspiration or removing the air once was predictive of resolution or need for surgery. In 2019, Leys et al. created a prospective protocol to test aspiration through a pigtail catheter followed by a 6-hour observation period with the tube clamped. 33 patients were managed on this protocol. The aspiration test was successful in 48% of patients and they were able to go home after the observation period. PSP did recur in 44% of the patients who passed the initial test. Of the patients that failed the initial test, 30% went directly to surgical intervention and 70% were managed with admission and a chest tube.

Of the patients admitted and managed with a chest tube, 83% had a recurrence of PSP and went on to surgical intervention. This study showed that initial aspiration as management is safe and if successful, has about 50% recurrence. If the initial aspiration test fails, it is predictive of needing surgical intervention.

Natural History of Patent Processus Vaginalis (PPV) in Infants

The processus vaginalis is the canal that travels along the inguinal ligament (groin crease). In males, it is the path in which the testicle descends during development, and in females, it contains a structure called the round ligament. This path is supposed to close during gestation, but occasionally it does not, and it is the source of groin hernias or fluid collections called hydroceles. Sometimes a patent processus vaginalis is asymptomatic and found incidentally during other abdominal surgery. The natural course of the incidental PPV is not well understood, and the frequency with which they become symptomatic or problematic is not known. St. Peter et al. have designed a prospective observational study currently enrolling patients who undergo laparoscopy for pyloric stenosis to inspect the inguinal ring for a patent processus vaginalis. This study will inform surgeons whether these are safe to observe or should be surgically repaired.

Nonoperative Management of Uncomplicated Appendicitis

Appendicitis remains the most common pediatric surgical emergency, and treatment with an appendectomy in children has been largely unchallenged. Recently there have been several studies showing the safety and efficacy of non-operative management with antibiotics alone, however, prospective large multi-institutional studies in children were lacking. In 2019 Minneci et al. published their study design and in 2020 they published their findings comparing operative vs. non-operative management of pediatric uncomplicated appendicitis. Across the participating centers, 1068 patients were enrolled in the study. Of those, 65% of patients and families chose surgery and 35% chose antibiotics alone. Of patients that chose not to have surgery, 63% were successful at 1 year of follow-up, and they had significantly fewer disability days (6.6 vs. 10.9) with similar quality of life and satisfaction scores. This showed the safety and efficacy of nonoperative management, challenging the traditional dogma, and has given providers and patients the information required to have informed discussions on the treatment approach.
The follow-up from this study is ongoing with active research and grant funding to continue studying the management of acute appendicitis within our consortium. We have been fortunate to partner with the Patient-Centered Outcomes Research Institute for project funding.

Ovarian Masses

Pediatric ovarian tumors are rare, occurring in up to 1 in 40,000 girls per year with about 20% being malignant. Ovarian masses can cause pain, torsion or twisting of the ovary and can harbor cancer making. Preoperative risk stratification and surgical treatment must balance the risk of malignancy with risks of future infertility. Given their rarity, the MWPSC decided to study various features of ovarian masses. In 2018 Lawrence et al. looked broadly at current management practices regarding ovarian tumors. They were able to identify 819 girls undergoing surgery.
Malignant lesions were found in 11% of cases, and oophorectomy (removal of the entire affected ovary) was done in 33% of benign cases. Factors associated with malignancy were younger age, abdominal bloating, enlarged lymph nodes, and increased size of the mass. Features associated with oophorectomy in benign cases were solid components on imaging, larger size, and initial suspicion for malignancy.
To help with this differentiation between malignant and benign lesions, Lawrence et al. also utilized the MWPSC to study the value of tumor markers in 2019. They used a population of 401 patients with at least one concerning feature for malignancy of which 22% had a confirmed malignancy on pathology. The results from their study found that the different tumor markers each contributed together as a panel to help with diagnosis. The markers that were most specific were AFP, Inhibin A and Inhibin B (98%, 97%, 92% respectively).
The markers with the highest sensitivity were LDH and beta-hCG (95%, 44% respectively). This data helps providers understand the utility of various tumor markers for ovarian masses and supports the use of a panel that combines tumor markers to help differentiate benign and malignant masses.
Another concern for ovarian masses is the risk of malignancy in patients that present with torsion. In 2021, Lawrence et al. used the consortium data to study ovarian torsion along with the associated risk factors and the risk of malignancy. They identified 814 girls with an ovarian mass, of which, 22% had an episode of torsion. Size greater than 5cm carried twice the risk of torsion. Other associated factors with torsion were younger age, abdominal pain, and vomiting. They also found that imaging had low reliability at detecting or ruling out ovarian torsion. Of the patients that had torsion from a mass, 48% had an oophorectomy as their operation. The authors saw a decreased risk of malignancy in torsed masses than in masses without torsion and have been able to provide evidence in favor of ovarian preservation during intervention for torsion.
The retrospective studies published have provided the foundation for prospective analysis on the management of ovarian masses using a standardized preoperative algorithm. This work is ongoing, we have completed enrollment in this study and are completing follow-up for this study. We have been fortunate to partner with Thrasher Research Fund for grant funding on this topic.

Pectus Excavatum

Pectus excavatum is the most common congenital chest wall deformity. Understanding the relative contributions of both center and surgeon volume, can shed light on the potential benefits of specialization. Additionally, comparing outcomes of various pain management strategies for patients undergoing the Nuss procedure, would allow centers and surgeons to adjust Enhanced Recovery Protocols. Regional anesthetic approach and surgical volume impact outcomes in patients undergoing Nuss procedure for pectus excavatum. However, their independent relationship is not described.
Speck et al. published a large multi-institutional review in the Journal of Surgical Research of analgesic approaches utilized for Nuss procedures in Pectus Excavatum. Significant variability in care was noted, including continued use of opioid-only methods. Our analysis supports and expands on previously published literature by demonstrating decreased length of stay and decreased postoperative opioid use when employing cryoablation, irrespective of center and surgeon volume. Erector spinae catheters were similarly seen to improve outcomes and represent another viable regional analgesic approach. Centers and surgeons performing pectus excavatum repair via the Nuss procedure should consider standardization via institution of an Enhanced Recovery Pathway including regional anesthetic approaches readily available at your institution to decrease opioid usage in this population. Future prospective studies comparing erector spinae catheters to cryoablation as regional anesthetic strategy could better delineate efficacy in post-operative pain control and outcomes.

Ovarian Masses

Pediatric ovarian tumors are rare, occurring in up to 1 in 40,000 girls per year with about 20% being malignant. Ovarian masses can cause pain, torsion or twisting of the ovary and can harbor cancer making. Preoperative risk stratification and surgical treatment must balance the risk of malignancy with risks of future infertility. Given their rarity, the MWPSC decided to study various features of ovarian masses. In 2018 Lawrence et al. looked broadly at current management practices regarding ovarian tumors. They were able to identify 819 girls undergoing surgery.
Malignant lesions were found in 11% of cases, and oophorectomy (removal of the entire affected ovary) was done in 33% of benign cases. Factors associated with malignancy were younger age, abdominal bloating, enlarged lymph nodes, and increased size of the mass. Features associated with oophorectomy in benign cases were solid components on imaging, larger size, and initial suspicion for malignancy.

To help with this differentiation between malignant and benign lesions, Lawrence et al. also utilized the MWPSC to study the value of tumor markers in 2019. They used a population of 401 patients with at least one concerning feature for malignancy of which 22% had a confirmed malignancy on pathology. The results from their study found that the different tumor markers each contributed together as a panel to help with diagnosis. The markers that were most specific were AFP, Inhibin A and Inhibin B (98%, 97%, 92% respectively).
The markers with the highest sensitivity were LDH and beta-hCG (95%, 44% respectively). This data helps providers understand the utility of various tumor markers for ovarian masses and supports the use of a panel that combines tumor markers to help differentiate benign and malignant masses.

Another concern for ovarian masses is the risk of malignancy in patients that present with torsion. In 2021, Lawrence et al. used the consortium data to study ovarian torsion along with the associated risk factors and the risk of malignancy. They identified 814 girls with an ovarian mass, of which, 22% had an episode of torsion. Size greater than 5cm carried twice the risk of torsion. Other associated factors with torsion were younger age, abdominal pain, and vomiting. They also found that imaging had low reliability at detecting or ruling out ovarian torsion. Of the patients that had torsion from a mass, 48% had an oophorectomy as their operation. The authors saw a decreased risk of malignancy in torsed masses than in masses without torsion and have been able to provide evidence in favor of ovarian preservation during intervention for torsion.
The retrospective studies published have provided the foundation for prospective analysis on the management of ovarian masses using a standardized preoperative algorithm. This work is ongoing, we have completed enrollment in this study and are completing follow-up for this study. We have been fortunate to partner with Thrasher Research Fund for grant funding on this topic.

Pectus Excavatum

Pectus excavatum is the most common congenital chest wall deformity. Understanding the relative contributions of both center and surgeon volume, can shed light on the potential benefits of specialization. Additionally, comparing outcomes of various pain management strategies for patients undergoing the Nuss procedure, would allow centers and surgeons to adjust Enhanced Recovery Protocols. Regional anesthetic approach and surgical volume impact outcomes in patients undergoing Nuss procedure for pectus excavatum. However, their independent relationship is not described.
Speck et al. published a large multi-institutional review in the Journal of Surgical Research of analgesic approaches utilized for Nuss procedures in Pectus Excavatum. Significant variability in care was noted, including continued use of opioid-only methods. Our analysis supports and expands on previously published literature by demonstrating decreased length of stay and decreased postoperative opioid use when employing cryoablation, irrespective of center and surgeon volume. Erector spinae catheters were similarly seen to improve outcomes and represent another viable regional analgesic approach. Centers and surgeons performing pectus excavatum repair via the Nuss procedure should consider standardization via institution of an Enhanced Recovery Pathway including regional anesthetic approaches readily available at your institution to decrease opioid usage in this population.Future prospective studies comparing erector spinae catheters to cryoablation as regional anesthetic strategy could better delineate efficacy in post-operative pain control and outcomes.

Pilonidal Disease

Pilonidal Disease occurs in approximately 1 in 4000 teenagers and young adults. It is a disease where hair collects in the gluteal cleft and creates epithelialized sinus tracts. These tracts can cause abscesses and infections as well as pain and discomfort. Traditional management has been wide excision of the tracts with either the healing of an open wound over time or flap coverage. Recently less invasive procedures commonly called the “Gips procedure” have shown good outcomes with faster recovery and less pain causing a paradigm shift in management. Even with this shift medical and surgical management is widely variable among providers. Through the MWPSC, Rymeski et al. have designed a multi-institutional prospective cohort study studying outcomes from various medical and surgical management. We have been fortunate to partner with American Pediatric Surgical Association for grant funding to support this research.
The MWPSC Pilonidal study completed enrollment at the end of 2022. The one-year follow up portion of the study was completed at the end of 2023.
Manuscripts are currently being written based on collected data.

Small Bowel Obstruction

Adhesive small bowel obstructions are a common cause of post-surgical morbidity. Without a clear indication for urgent surgical intervention, a trial of non-operative management has been established as a safe and effective initial management strategy. Traditionally, this includes gastric decompression, fluid resuscitation, and bowel rest; however, optimal duration of non-operative approaches and predictive criteria for surgical intervention have yet to be defined. In adults, hyperosmotic, water-soluble contrast agents have been integrated into the non-operative management of ASBO since the 1990s with both diagnostic and therapeutic benefits. Supportive literature for the use of contrast in children with ASBO has been limited but is growing. Despite this, there remains ongoing variability in national management practices without evidence-based guidelines and best practices for children.
Speck et al. published a 5-center retrospective study of in 2023 which demonstrated 100% sensitivity and 86% specificity of a contrast challenge in identifying pediatric patients who could be successfully managed non-operatively. The group followed this review with an MWPSC 11-institution prospective implementation study of a standardized contrast algorithm to evaluate clinical safety and effectiveness. The study was recently published in Annals of Surgery in 2025 and demonstrated that hyperosmolar water-soluble contrast challenges are safe with high diagnostic and therapeutic utility in children with adhesive bowel obstructions. The algorithm also provided detailed pediatric contrast dosing recommendations not previously available, is readily implementable, and broadly transferable across institutions caring for children. The 1-year follow up study is currently underway.

Spontaneous Pneumomediastinum

In the absence of penetrating/high-energy trauma, pediatric spontaneous pneumomediastinum has a predictably benign course. Despite this, evaluation and management are highly variable. Patients are admitted and/or undergo multiple imaging studies that rarely change clinical management. This study aims to identify spontaneous pneumomediastinum patients at low-risk for serious injury to avoid the feared missed esophageal injury. In 2022, Speck et al. published a single institution review that demonstrated pediatric patients with spontaneous pneumomediastinum benefit from evaluation, management, and treatment based on their presenting symptoms. There is an opportunity to decrease unnecessary radiation exposure in this patient population with fewer CXRs and avoidance of esophagrams, neither of which alter management. This is currently being followed up with an 11-institution MWPSC study to validate these findings.

Thyroid Disease

Both benign and malignant thyroid disease occurs in the pediatric population. As with many other pediatric diseases, the incidence is rare and difficult to study in a single institution. Therefore, most recommendations and guidelines on medical and surgical management of pediatric thyroid disease are founded on adult-based evidence. Through the MWPSC, Bruch et al. are studying all aspects of pediatric thyroid disease. The initial workup and evaluation, imaging, surgical intervention and complications, adjuvant radioactive iodine, and follow-up are being studied from patients across the consortium. This will provide the first multi-institutional evidence-based guidelines that are pediatric-specific. They also plan to continue this prospectively as the largest known pediatric thyroid registry.

Venous Thromboembolism in Pediatric Trauma Patients

Venous Thromboembolism (VTE) includes a spectrum of clotting diseases from deep vein thrombosis (blood clots in the legs/arms) to Pulmonary Embolism (blood clots in the lungs) that can be life-threatening. It is well known that the trauma population is at high risk for VTE, particularly if they suffered a major brain or bone injury and if they have limited mobility. Interventions such as pharmacologic prophylaxis with a blood-thinning medication as well as early mobility and mechanical compression devices have greatly reduced the incidence of VTE in the adult trauma population. Pediatric trauma patients are also at risk for VTE but several questions around the indications, timing, population, and safety of VTE prophylaxis.
The MWPSC conducted the first prospective natural history study of VTE prophylaxis in pediatric trauma patients.
The goals of the study were to:
1. Develop and institute screening criteria to identify high risk pediatric trauma patients for VTE
2. Perform multi-institutional, prospective validation
3. Demonstrate safety of chemical prophylaxis (LMWH)
The results showed
1. Prophylaxis is safe
2. Validation of criteria
3. Early VTE prophylaxis in a high risk group reduces the risk of VTE
4. Substantial proportion of children under 14 develop VTE
5. CVL use is highly associated with VTE