Jacob T. Stephenson

The Effect of Fiber Alignment and Heparin Coating on Cell Infiltration into Nanofibrous PLLA Scaffolds

Biodegradable nanofibers simulate the fibril structure of natural extracellular matrix, and provide a cell-friendly microenvironment for tissue regeneration. However, the effects of nanofiber organization and immobilized biochemical factors on cell infiltration into three-dimensional scaffolds are not well understood. For example, cell infiltration into an electrospun nanofibrous matrix is often limited due to relatively small pore size between the fibers. Here we showed that biophysical and biochemical modification of nanofibrous scaffolds facilitated endothelial cell infiltration in three-dimensional scaffolds in vitro and in vivo. Aligned nanofibers significantly enhanced cell infiltration into the nanofibrous matrices in vitro. In a full-thickness dermal wound model, the nanofiber scaffolds enhanced epidermal skin cell migration across the wound when compared to a control group without scaffold. Aligned nanofibers promoted the infiltration of endothelial cells into the scaffolds. Furthermore, heparin-coated nanofibers also increased cell infiltration significantly. These results shed light on the importance of biophysical and biochemical properties of nanofibers in the regulation of cell infiltration into three-dimensional scaffolds and tissue remodeling.

Magnamosis II: Magnetic Compression Anastomosis for Minimally Invasive Gastrojejunostomy and Jejunojejunostomy

BACKGROUND Previously we demonstrated the safety and patency of a magnetic compression anastomosis (magnamosis). We present the further development of this technique, with specific focus on optimizing device design for minimally invasive magnamosis. STUDY DESIGN The magnamosis device was designed to incorporate 3 features: 2 convex-concave radially symmetric halves that magnetically self-align, a central channel for immediate patency, and specially engineered radial topography of the mating surfaces to promote gradual remodeling. Each symmetrical half consists of a ring-shaped neodymium-iron-boron magnet encased in polycarbonate casing. Twenty-one young adult pigs underwent either magnetic gastrojejunostomy (n = 13) or jejunojejunostomy (n = 8). Animals were euthanized at 1, 2, 4, and 6 weeks after operation. Anastomoses were studied with contrast radiography, burst pressure, and histology. RESULTS Gastrojejunostomy: In all animals with successful placement of magnets, anastomoses were patent by contrast fluoroscopy, well healed by histologic examination, and showed excellent burst strength. Jejunojejunostomy: All animals had uneventful clinical courses, indicating that the magnamosis with immediate patency functioned properly without device dislodgement. At sacrifice, all magnamoses were patent, well healed by histology, and had burst strengths that equaled or exceeded that of traditional stapled anastomoses. CONCLUSIONS Minimally invasive placement of a custom magnetic device in the stomach and jejunum allows intraluminal self-alignment and subsequent compression anastomosis over 3 to 10 days. The magnamosis is immediately patent and develops strength equal to or greater than that of hand-sewn or stapled anastomoses. Magnamosis is effective in the pig model, and may be a safe, effective, and minimally invasive alternative to current anastomotic strategies in humans.

Compressive orthotic bracing in the treatment of pectus carinatum: the use of radiographic markers to predict success

PURPOSE The treatment of pectus carinatum (PC) has classically been operative, though compressive orthotic braces have been used with good success in recent years. The purpose of this article is to evaluate the use of radiologic measurements in a successful bracing protocol. METHODS Sixty-three patients with PC have been evaluated for an 8-year span. The average age is 13.3 +/- 2.5. Follow-up is from 4 to 60 months, with a median of 24 months. Seventeen patients with mild defects elected observation alone. The remaining 46 patients began the bracing protocol. Baseline chest computed tomography (CT) was obtained, and custom-fitted orthotic braces were constructed for each patient. Radiographic markers were evaluated to include the Haller index, angle of sternal rotation, and asymmetry index. Patient surveys and chart review were used to identify compliance and success rates. Pretreatment CTs were retrospectively reviewed by bracing outcomes and radiographic measurements were compared. Ten patients received posttreatment CTs after successful bracing. RESULTS Of 63 patients with PC, 17 patients (27%) with mild defects elected observation alone. The remaining 46 patients began the bracing protocol as described above. Of these, 10 are excluded from analysis, with 6 patients currently in the early treatment phase and 4 who have been lost to follow-up. Of the remaining 36 patients, 8 failed bracing because of noncompliance. Of the 28, 24 patients who completed treatment report either good or excellent results after bracing. Eight patients have required surgical intervention, 4 as a result of noncompliance and 4 who were compliant but failed bracing. In patients who were compliant, significant differences were seen on initial CT between those with successful outcomes and those who required surgical repair. Haller index (2.85 vs 2.05; P < .05), angle of sternal rotation (27.3 vs 14.8; P < .05), and asymmetry index (1.23 vs 1.06; P < .01) were all higher in the group who failed bracing. In those who successfully completed treatment, there was no significant difference in the Haller or asymmetry indices, but the average improvement in sternal rotation was 53.8%. CONCLUSION Compressive orthotic bracing is a successful method of treatment of pectus carinatum. The associated sternal rotation can be significantly improved with appropriate bracing that results in a subjective improvement in the deformity. Asymmetry of chest diameter related to concomitant excavatum-type deformity is less likely to respond to bracing attempts. In this way, initial chest CT can be of value in treatment planning.

Novel titanium constructs for chest wall reconstruction in children

PURPOSE We have previously reported the use of the vertical expandable prosthetic titanium rib (VEPTR) for treatment of thoracic dystrophy. This report describes our experience with this device and other novel titanium constructs for chest wall reconstruction. METHODS This is a retrospective chart review of all children and adolescents undergoing chest wall reconstruction with titanium constructs between December 2005 and May 2010. RESULTS Six patients have undergone chest wall reconstruction with VEPTR or other titanium constructs. Four had chest wall resection for primary malignancy, 1 had metastatic chest wall tumor resection, and 1 had congenital chest wall deformity. There were no immediate complications, and all patients have exhibited excellent respiratory function with no scoliosis. CONCLUSIONS Chest wall reconstruction after tumor resection or for primary chest wall deformities can be effectively accomplished with VEPTR and other customized titanium constructs. Goals should be durable protection of intrathoracic organs and preservation of thoracic volume and function throughout growth. Careful preoperative evaluation and patient-specific planning are important aspects of successful reconstruction.

Ewing sarcoma/primitive neuroectodermal tumor arising from the adrenal gland in an adolescent†

We review the case of an adolescent who presented with flank pain, fatigue and a discrete nonfunctioning adrenal lesion which was found to be an adrenal Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET). The patient was treated with a minimally invasive adrenalectomy as a component of multimodal therapy, including seven courses of chemotherapy and whole abdominal radiation. She is currently disease free 14 months after the operation and 3 months off therapy. Pediatr Blood Cancer 2011; 57: 691–692.

Intradiaphragmatic pulmonary sequestration: advantages of the thoracoscopic approach

Pulmonary sequestrations are accessory foregut lesions that are most commonly located within the thorax and occasionally in the abdominal cavity. Sequestrations arising within the diaphragm are exceedingly rare. We describe 2 patients found to have left peridiaphragmatic lesions on prenatal ultrasound and postnatal computed tomography. In the first patient, an initial laparoscopic approach was abandoned in favor of a thoracoscopic approach after no intraabdominal mass was found. The second patient had an uncomplicated thoracoscopic resection of a similar lesion. To our knowledge, these represent the first intradiaphragmatic pulmonary sequestrations to be resected via a minimally invasive approach. The rarity of these lesions makes definitive diagnosis without operative intervention challenging. Thoracoscopy appears to be a reasonable approach for resection of such intradiaphragmatic lesions.

In utero repair of gastroschisis in the sheep (Ovis aries) model

OBJECTIVE Gastroschisis is associated with inflammatory changes in the exposed bowel which leads to intestinal dysmotility after postnatal repair. The insult is a combined effect of amniotic fluid exposure and mechanical constriction. We hypothesized that in utero anatomic repair is possible in a sheep model, and that it may halt the inflammatory damage caused by both mechanisms. METHODS Gastroschisis was surgically created in mid-gestation (day 75) in 8 sheep fetuses. On gestational day 100, 2 fetuses underwent open fetal gastroschisis repair, where the eviscerated bowel was returned to the peritoneal cavity, and the abdominal wall was primarily closed. All fetuses were harvested at 135 days of gestation. RESULTS Six fetuses survived the initial operation, and both fetuses that underwent gastroschisis repair survived to term. At 100 and 135 days of gestation, the eviscerated bowel showed progressive signs of inflammation and peel development. The gross and microscopic inflammatory changes in the gastroschisis bowel at 100 days of gestation were completely resolved at term following in utero repair. CONCLUSION In utero anatomic repair of gastroschisis is possible in mid-gestation in the fetal lamb model, and it appears to ameliorate the inflammatory process.

Laparoscopic management of neonatal paraesophageal hernia with intrathoracic gastric volvulus

Intrathoracic gastric volvulus associated with neonatal paraesophageal hernia is very rare in the newborn period. We report a case of a 3-week-old term infant who presented to the hospital with a history of non-bilious vomiting. Workup for hypertrophic pyloric stenosis eventually revealed the presence of a congenital hiatal hernia and intrathoracic gastric volvulus requiring urgent surgical management. The infant underwent successful laparoscopic repair. We discuss the diagnosis and management of this extremely rare surgical cause of neonatal nonbilious emesis.

Noningested intraperitoneal foreign body causing chronic abdominal pain: a role for laparoscopy in the diagnosis

In this article, we present an unusual case of a young boy who presented with abdominal pain and was found to have a sewing needle that had migrated through the abdominal wall into the peritoneal space. After imaging and endoscopy, the needle was extracted laparoscopically without any evidence of intra-abdominal organ injury and with a good long-term outcome for the child. There are no other such reported cases in the literature. This case highlights the subtleties in management of intra-abdominal foreign bodies in children including rare causes such noningested foreign bodies.