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Biomedical subjects

N S Adzick

Publications and source records attributed to N S Adzick.

At least 19 recordsLinked to original sources
PubMed1992

Adult-to-neonate lung transplantation: anatomic considerations.

Babies born with severe pulmonary hypoplasia are unsalvageable despite maximal therapy including extracorporeal membrane oxygenation (ECMO). Using ECMO as a bridge to transplantation, reduced-size lung grafts (pulmonary lobe or segment) could expand the pool of cadaver donors and may allow for HLA-matched living-related transplants. We tested this concept first in the piglet model and developed the technical maneuvers necessary to perform lobar and segmental lung transplants from adult pigs into neonatal piglets. Prior to clinical application, a systematic evaluation of anatomic considerations for reduced-size human lung transplantation was needed. A series of human adult and neonatal cadaver thoracic dissections were performed to determine the adult pulmonary lobe or segment with the proper size, orientation, and vascular and bronchial anatomy for use as a neonatal lung transplant. The adult right middle lobe (RML) is the best candidate for neonatal left lung replacement. The adult RML, once removed, can be rotated 180 degrees around its superior-inferior axis and the vessels and bronchus align well in the left chest of the neonate. The RML may require further reduction to fit into the neonatal left chest. Selective arterial perfusion of the RML showed the anterior segment to be a near-perfect match for fit and anatomy. This technique may eventually permit living-related lung transplantation.

Adult↗
PubMed1992

New techniques in fetal surgery.

Optimal fetal management during and after fetal surgery has been limited by an inability to reliably monitor the fetal heart rate and temperature, and by a lack of access to the fetal circulation. In order to solve these problems, we used early third trimester fetal sheep to develop: (1) an implantable radiotelemetry device that transmits the fetal electrocardiogram and temperature, and (2) an intraosseous access technique. A miniaturized radiotelemeter was implanted subcutaneously in the axilla of four fetal sheep. Safe implantation of the radiotelemeter was technically feasible and the device reliably recorded the fetal electrocardiogram and temperature both intraoperatively and postoperatively. Although many possible routes for access to the fetal circulation have been tried experimentally and clinically for both resuscitation and blood sampling, none have proven satisfactory. We assessed the use of intraosseous access in fetal sheep (n = 6) for both infusion and blood sampling. Access with an intraosseous needle was obtained in both sheep fetuses and human fetal cadavers. Blood gas values (pH, PCO2, and PO2) obtained from the medullary cavity of fetal sheep accurately reflected peripheral venous values. Resuscitation drugs reached the fetal circulation via the intraosseous route: sodium bicarbonate elevated venous bicarbonate levels from 28.4 +/- 1.7 to 31.8 +/- 2.1 mEq/dL (P < .05); injected glucose increased venous glucose levels by 520 +/- 108 mg/dL (P < .01); and injection of calcium chloride elevated venous calcium levels from 11.8 +/- 0.7 to 15.2 +/- 2.2 mEq/dL (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Tracheostomy in children with emphasis on home care.

Tracheostomy in children is not a benign procedure. Tracheostomy-related mortality rates among children have been previously reported to be as high as 10% to 27%. Children with tracheostomies are especially vulnerable after home discharge with mortality rates of 0.5 to 2 deaths per 100 months at home. In order to assess the impact of extensive parental education and home nursing care on tracheostomy-related mortality, we report our experience over 9 years with 44 children receiving tracheostomies. Each child was maintained at home with a tracheostomy for an average of 19 months for a total of 635 months of home tracheostomy care. Indications for tracheostomy were tracheomalacia (32%), obstructive airway lesions (23%), central nervous system lesions (16%), vocal cord paralysis (9%), Pierre Robin syndrome (9%), and a list of miscellaneous conditions (11%). Our tracheostomy care regimen begins with intensive parental training in tracheostomy management for a minimum of 10 days prior to discharge. Home nursing was arranged for 77% of these children for an average of 11 hours per day at the time of discharge. Eighty-three percent had home apnea monitors. Discharge of these children was delayed or transfer to a secondary hospital was made when parents failed to show adequate proficiency in tracheostomy management with existing home nursing. Eight percent were ventilator dependent at discharge. As of January 1, 1989, 34% of these children have been decannulated. There were six deaths, all due to underlying disease. There were no tracheostomy-related deaths in hospital or after discharge home.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1992

Necrotizing fasciitis in two children with acute lymphoblastic leukemia.

Necrotizing fasciitis is a severe, soft tissue infection, and is an unusual condition in children. The cornerstone of therapy is prompt, aggressive surgical treatment. Despite vigorous treatment, mortality rates are high. We report the occurrence of necrotizing fasciitis in two children during the granulocytopenic phase of induction chemotherapy for acute lymphoblastic leukemia. The diagnosis and treatment of necrotizing fasciitis in these two children was made more difficult by their underlying disease and its chemotherapy. The successful treatment of their infections relied on a multimodality approach. Aggressive surgical debridement was the mainstay of therapy. Adjuvant therapy was vital to the successful outcomes and included meticulous wound care, intravenous hyperalimentation, appropriate antibiotics, and granulocyte transfusions.

Agranulocytosis↗
PubMed1992

Fetoscopic surgery for the treatment of congenital anomalies.

Fetoscopic techniques may broaden the indications for prenatal surgical intervention by obviating the risks of hysterotomy. For example, congenital obstructive uropathy has been treated by open vesicostomy and percutaneous catheter placement. The open approach is appropriate only for highly selected fetuses because of the inherent risks, whereas catheter drainage, though a safer procedure, is only useful for short-term therapy late in gestation due to frequent catheter obstruction and migration. The natural history of congenital obstructive uropathy mandates the need for improved therapy earlier in gestation, in order to salvage fetuses who would otherwise die of renal failure and pulmonary hypoplasia. We have developed a potential solution to this problem in which surgery is performed on the fetus without the risks of hysterotomy. Endoscopic fetal surgery uses a telescopic lens and operating instruments that are passed through small "ports" in the uterus. A bubble of CO2 is used to displace amniotic fluid and provides excellent visualization in a magnified field. This approach is considerably less invasive than open fetal surgery and, therefore, is less likely to provoke preterm labor. In this study we corrected obstructive uropathy in midgestation fetal lambs using a new, expandable wire mesh stent that is placed endoscopically and should provide more reliable bladder drainage than existing catheters. The fetoscopic surgical approach can potentially expand the indications for in utero surgery by decreasing fetal risks, facilitating intervention earlier in gestation, and reducing preterm labor. As a consequence, the potential now exists to correct non-life-threatening malformations in utero.

Animals↗
PubMed1992

Retroperitoneal alimentary tract duplications detected in utero.

The prenatal diagnosis of numerous congenital anomalies has become routine. The prenatal diagnosis of cystic lesions of the retroperitoneum can be due to a variety of renal, gastrointestinal, or adrenal lesions. This finding demands aggressive postnatal follow-up to rule out the possibility of cystic adrenal neuroblastoma. We report the first cases of retroperitoneal cystic masses diagnosed in utero that ultimately proved to be enteric duplications. Therefore, the differential diagnosis of cystic masses of the retroperitoneum found prenatally should be expanded to include enteric duplication cysts.

Cysts↗
PubMed1992

Outcome of antenatally diagnosed cystic adenomatoid malformations.

OBJECTIVE: Twenty-two cases of antenatally diagnosed congenital cystic adenomatoid malformations are reported. STUDY DESIGN: Case management is reviewed. RESULTS: Eighteen women continued pregnancy after diagnosis. In nine cases nonimmune hydrops fetalis did not develop and all infants survived. Nonimmune hydrops fetalis developed in the other nine; fetal intervention was performed in eight cases. In the single case of nonimmune hydrops fetalis without intervention, the neonate died. In four cases aspiration of macrocystic lesions was performed. In two cases cystoamniotic shunts were placed. Neither aspiration or shunting provided long-term benefit. In six cases fetal lobectomy was ultimately performed and four survived. Two fetuses did not undergo in utero surgery; one was delivered prematurely after cyst aspiration and lived, and the other previable fetus was delivered soon after shunting. CONCLUSIONS: Fetal survival is best related to development of nonimmune hydrops fetalis. Aspiration of cystic lesions and cystoamniotic shunts generally provide short-term benefit. Early experience with fetal surgery for congenital cystic adenomatoid malformations has been encouraging.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed1992

A novel endoscopic transgastric fundoplication procedure for gastroesophageal reflux: an initial animal evaluation.

Complications of gastroesophageal reflux are common in adults and children. A variety of surgical procedures have been successfully used to treat this condition. All current techniques require open surgery and are associated with significant morbidity and mortality, particularly in the high risk, neurologically damaged child. The authors have developed a novel method of creating a gastric fundoplication using an endoscopic transgastric approach in pigs. The procedure involves the creation of an esophageal intussusception into the stomach under direct vision with an endoscope. The gastric fundus is then plicated around the esophagus using a custom stapling device. The transgastric approach allows creation of a fundoplication, is easily performed, is potentially effective at preventing gastroesophageal reflux, and has the obvious advantages of minimally invasive surgery over open techniques of fundoplication.

Animals↗
PubMed1992

Scarless fetal healing. Therapeutic implications.

The purpose of this report is to call attention to the fetal wound healing process as a blueprint for ideal tissue repair. Wound healing in the fetus is fundamentally different from healing in the adult. Fetal tissue repair occurs rapidly and in the absence of scar formation. Because scarring and fibrosis dominate some diseases in every area of medicine, an understanding of fetal wound healing should help develop therapeutic strategies to avert the devastating consequences of excessive scar formation.

Adult↗
PubMed1992

An in utero model of craniosynostosis.

To define better the pathophysiology of craniosynostosis, we developed an in utero model in rabbits. Premature fusion of the sutures was achieved by osteoinduction using demineralized bone matrix (DBM). Thirty-six fetuses from 18 time-dated pregnant rabbits underwent coronal strip craniectomies and implantation of DBM at 25 days of gestation (term = 31 days). Seventeen (47%) survived vaginal delivery and 10 (28%) survived for long-term follow-up. Surviving, operated animals demonstrated bony fusion across the coronal sutures presumably due to osteoinduction by the DBM. Coronal computed tomographic scans with sagittal reconstructions revealed that experimental animals had taller and wider skulls than nonoperated control animals. We conclude that employing DBM to create craniosynostosis in the fetal rabbit is technically feasible. Such a model may be used to more clearly define the pathophysiology of craniosynostosis and to evaluate methods of treatment.

Animals↗
PubMed1992

A model for fetal cleft lip repair in lambs.

Fetal wounds heal without inflammation and scar formation. This phenomenon may, in the future, be applicable to human cleft lip and palate repair. However, extensive experimental work must first be done to document the benefits of in utero repair. We developed a large animal model for creation and repair of a complete cleft lip and alveolus using fetal lambs. The cleft lip and alveolus deformity was created in eight 75-day-gestation fetuses (term = 145 days) and either repaired in three layers or left unrepaired. There were four sham-operated fetuses, and all animals were alive at harvest. Repaired, unrepaired, and control fetuses were harvested at 7, 14, 21, and 70 days following surgery. The unrepaired fetuses demonstrated a complete cleft lip and alveolus with an oronasal fistula. The maxilla was asymmetrical, with the greater segment deviated toward the cleft and with decreased anterior maxillary width. In contrast, repaired cleft lip and alveolus animals showed no scar, normal thickness of the lip, and a symmetrical maxilla. Histologic analysis of the repaired wounds showed evidence of tissue regeneration without scar formation. The results of this preliminary study indicate that the fetal lamb cleft lip and alveolus model is technically feasible with an excellent survival rate. Healing occurs without scar formation. In the repaired animals, the maxilla was symmetrical. This model will be used to document facial growth following in utero repair of a cleft lip and alveolus.

Alveolar Process↗
PubMed1992

Scarless wound repair: a human fetal skin model.

Animal studies demonstrate that the fetus heals cutaneous wounds by reformation of normal tissue architecture without scar formation. We have developed a new model to study human fetal skin wound healing. Grafts of human fetal skin placed onto athymic mice retain the morphologic features of normal development, although they differentiate at an accelerated rate when placed cutaneously compared to subcutaneously. Full-thickness skin grafts from human fetuses at 15 (n = 12), 17 (n = 11), 18 (n = 25), 19 (n = 20) and 22 (n = 13) weeks gestational age were placed onto athymic (nu/nu) mice in 2 locations: (1) cutaneously onto a fascial bed and thereby exposed to air or (2) subcutaneously in a pocket under the murine panniculus carnosus. Linear incisions were made in each graft 7 days after transplantation. Grafts were harvested at 7, 14 and 21 days postwounding and analyzed histologically for scar formation. By hematoxylin & eosin and Mallory's trichrome stains, complete epidermal and dermal graft wound healing without scar formation was demonstrated in the subcutaneous grafts at each gestational age studied. In contrast, scar was seen at all time points in the cutaneous grafts in both the incisional wound and at the interface of the fetal human skin graft and adult mouse skin, regardless of fetal skin gestational age.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Endoscopic creation and repair of fetal cleft lip.

In utero repair of several life-threatening malformations in the human fetus is now a clinical reality, yet fetal surgery still poses significant risks to both the mother and the unborn child. Preterm labor is a major problem and is directly related to the large hysterotomy required for fetal exposure. Endoscopic surgical manipulation of the fetus, through small uterine "ports," solves this problem and may eventually permit fetal intervention for non-life-threatening malformations. In this pilot study we demonstrated the feasibility of performing endoscopic surgery on the fetus in situ. A lip incision was created and repaired using endoscopic microsurgical techniques in midgestation fetal lambs. This represents the first application of this technique for in utero fetal intervention.

Animals↗
PubMed1992

Fetal fracture healing in a lamb model.

A large animal model to assess fetal fracture repair and the ability to close excisional bony defects is presented. Incisional and excisional ulnar fractures were made in 14 midgestation fetal lambs, harvested at serial time points, and subjected to high-resolution low-kilovolt magnification radiographs, magnetic resonance imaging scans, and histologic analysis. Fetal fracture healing was characterized by early closure of excisional defects and rapid fracture healing with minimal or no soft-tissue inflammation or callus formation. Magnetic resonance imaging scans of the fractures revealed a characteristic pattern compatible with the histologic findings, namely, minimal inflammation in soft tissue adjacent to the fracture site. Histologic and magnification radiographic findings indicated that complete bony repair occurred within 21 days in incisional defects and within 40 days in excisional defects. In both cases, healed fetal bone resembled normal bone matrix. Excisional defects, including periosteum, of greater than three times the width of the bony cortex closed rapidly with virtually normal-appearing bony matrix and with minimal or no callus formation.

Animals↗
PubMed1991

Hyaluronidase levels in urine from Wilms' tumor patients.

The pathophysiology of Wilms' tumor is associated with major alterations in hyaluronic acid metabolism. Elevated levels of both hyaluronic acid and a hyaluronic acid-stimulating activity occur in the urine and serum of patients with this tumor. In the current study, we describe elevated levels of urinary hyaluronidase in five patients with Wilms' tumor. Following surgical removal of the tumor, enzyme levels decreased toward normal. Characterization of enzyme activity indicates that hyaluronidase may be produced by the tumor itself. Alternatively, normal renal tissue may also be producing enzyme in a compensatory response to the elevated hyaluronic acid levels in these patients. We suggest that urinary hyaluronidase can be used as an additional marker for Wilms' tumor.

Biomarkers, Tumor↗
PubMed1991

Sheep amniotic fluid has a protein factor which stimulates human fibroblast populated collagen lattice contraction.

Sutured incisional wounds made in fetal sheep and rabbits heal without scarring. Fetal sheep excisional wounds can close by contraction, but those in fetal rabbits do not. In vivo and in vitro evidence suggests that rabbit amniotic fluid inhibits wound contraction. The question arises: does sheep amniotic fluid promote wound contraction because their fetal wounds close by contraction? Sheep amniotic fluid (SAF) from 100 and 125 days gestation was tested in fibroblast populated collagen lattice (FPCL) system, an in vitro model of wound contraction. SAF stimulated FPCL contraction in a dose responsive manner. SAF from a 100 day fetus was more stimulating than a 125 day SAF. SAF enhanced FPCL contraction in the presence or absence of serum. SAF was fractionated by size, using column chromatography. It yielded a fraction with an estimated molecular weigh near 40,000 daltons, which stimulated FPCL contraction. The factor was inactivated by proteolytic digestion and heat denaturation. This protein fraction which stimulates FPCL contraction is not related to 1) actin-myosin filaments enhanced contraction by ATP-induced cell contraction, 2) promotion of fibroblast elongation on glass surface or in collagen, or 3) increased cell number by enhanced fibroblast duplication in a collagen matrix. A mechanism for SAF promotion of FPCL contraction was investigated but not identified.

Adenosine Triphosphate↗
PubMed1991

In utero arterial embolism from renal vein thrombosis with successful postnatal thrombolytic therapy.

Thromboembolic events in the pediatric age group occur most commonly in neonates, and newborns of diabetic mothers are particularly at risk. We report a newborn with right renal vein and inferior vena cava thrombosis who apparently embolized across the foramen ovale antenatally with resultant right brachial artery occlusion. The baby was delivered by cesarean section from an insulin-dependent diabetic mother. At the time of birth, there was severe right arm ischemia with absent brachial and radial pulses. There was clinical evidence of distal embolization with a "trash" lesion of the distal right middle finger as well as a midforearm area of full-thickness skin loss. Ultrasound demonstrated a right renal vein thrombosis and a 95% occlusion of the inferior vena cava. Regional urokinase therapy was instituted through a lower extremity vein with a 5,000 U/kg bolus and then 5,000 U/kg/h continuous infusion. Twelve hours of infusion of urokinase led to clinical resolution of the right arm ischemia, with return of pulses. Follow-up ultrasound showed the right renal vein thrombosis and inferior vena cava clot to be completely resolved. The right middle finger and forearm lesions subsequently have healed primarily. We report this as a case of in utero arterial embolization with successful postnatal therapy using regional urokinase infusion.

Arm↗