Positron emission tomography studies confirm the need for early surgical intervention in patients with single-suture craniosynostosis.

Craniosynostosis, the premature fusion of one or more cranial sutures, may occur in isolation or in association with a syndromic constellation. Multiple-suture synostosis has consistently been associated with brain compression and increased intracranial pressure, and frequently decreased cognitive development. Single-suture craniosynostosis, however, has been thought by some to be an aesthetic problem with infrequent consequences on brain function and development. Some studies have disputed this concept and have argued a correlation between single-suture craniosynostosis and abnormalities in development. The purpose of this study was to determine, using an objective radiographic tool, positron emission tomography scans, if patients with single-suture craniosynostosis had any abnormalities in cerebral glucose metabolism that would indicate changes in local brain function. A total of 10 children with single-suture craniosynostosis, eight males and two females, ranging in age from 0.1 to 3.2 years, were enrolled in this prospective study approved by the Internal Review Board. Six of the children had sagittal synostosis, three had metopic synostosis, and one had coronal craniosynostosis. Each of the patients had preoperative positron emission tomography scans performed 1 to 5 weeks before cranial reconstructive surgery and postoperative scans at 6 to 12 weeks after surgery. Surgical treatment consisted of cranial vault remodeling in eight of the children and strip craniectomy with cranial expansion in two of the children. After surgery, the two scans were compared qualitatively and quantitatively by a single radiologist. The results demonstrated variable regional increases and decreases in local post-operative cerebral glucose metabolism. However, in the posterior occipital region, the area of visual development and visual spatial coordination, there was a consistent postoperative increase in all 10 patients. Maximum glucose metabolic rate was increased up to 30.2% with a mean of 9.9%, and average glucose metabolic rates demonstrated a maximum increase of up to 18.8%. The results of this study indicate cerebral glucose metabolism consistently increases in the posterior occipital cortex after surgical release of single-suture craniosynostosis. Future developmental studies are being performed to examine the functional consequences of these metabolic changes.

Vacuum-assisted closure for the treatment of degloving injuries.

Degloving injuries of the hand and foot pose difficult reconstructive and rehabilitation challenges. After an excellent experience with split-thickness skin grafting with the vacuum-assisted closure device, we began studies with full-thickness skin grafts and traumatized skin. The device has been used with successful reapplication of full-thickness degloved skin in two patients. The first patient suffered degloving of the foot; the second patient, degloving of the hand.

A controlled subatmospheric pressure dressing increases the rate of skin graft donor site reepithelialization.

The ability to increase the rate of skin graft donor site reepithelialization significantly in a cost-effective manner has important implications for the patient undergoing major reconstructive procedures. In this study the effect of externally applied reduced pressure (the V.A.C.) on the rate of healing of donor site wounds was initially investigated using a porcine model (N = 4), then repeated on humans (N = 10). Split-thickness skin grafts were harvested from the backs of pigs using standard technique. Half of the donor sites were treated with subatmospheric pressure (125 mmHg) and half were treated with an OpSite dressing. Biopsies taken every 48 hours demonstrated that sites exposed to reduced pressure healed at a much faster rate than sites treated with a standard occlusive dressing. Similarly, donor sites in humans reepithelialized faster in 7 of 10 patients, the rate was the same in 2 of 10 patients, and OpSite was faster in 1 of 10 patients. We believe this technology has the potential to be a relatively simple and cost-efficient method for increasing the rate of donor site healing.

Presentation and treatment of spontaneous aortocaval fistula.

BACKGROUND: Spontaneous rupture of abdominal aortic aneurysm into the inferior vena cava is rare. The clinical presentation is highly variable, and the diagnosis can be difficult, often being made only at operation. The aortocaval fistula results in a large left-to-right shunt, which can cause cardiac failure. Once the diagnosis is made, treatment is by surgical closure of the fistula and repair of the aneurysm with a graft. METHODS: This is a retrospective review of a single surgeon's experience with aortocaval fistula complicating abdominal aortic aneurysms. RESULTS: Over a 15-year period, we had five patients with spontaneous aortocaval fistula who were treated operatively. Preoperative diagnosis was made in two, suspected in one, and not made in two, one of whom died (the only perioperative death in the series). CONCLUSIONS: Spontaneous aortocaval fistulas are uncommon, and their preoperative recognition is difficult. Hematuria in association with an abdominal aortic aneurysm should raise the suspicion of an aortocaval fistula. Surgical correction is possible, with survival rates comparable to those associated with rupture of aneurysms into the retroperitoneum. Early operative control of the fistula is important to optimize the preload to the heart.

Effect of synchronous and asynchronous pulsatile flow during left, right, and biventricular bypass.

Ventricular assist devices augment flow from the left atrium to the aorta and/or from the right atrium to the pulmonary artery. Most devices are used in the asynchronous full-to-empty mode (asynchronous) but may also be used in a synchronous counterpulsation mode (synchronous). This study determines the optimal assist modes to reduce myocardial oxygen consumption (MVO2) and metabolism. Twelve pigs were instrumented with carotid artery and Baim coronary sinus catheters for determination of MVO2 and myocardial lactate production (LACT). Six were implanted with a Pierce-Donachy left ventricular assist device (LVAD) and 6 with both right and left ventricular assist devices (BIVAD). Two periods each of control, synchronous, and asynchronous bypass were instituted, the midanterior descending coronary artery (LAD) was ligated, and the sequence was repeated. After each period, MVO2 and LACT were determined and myocardial biopsy specimens were obtained for tissue, lactate, and ATP assay. Following LAD ligation, biopsy specimens were obtained from both the infarct and noninfarct zones of the heart. MVO2 decreased (p < 0.05) in the asynchronous BIVAD mode compared with control. MVO2 was unchanged in synchronous BIVAD or either LVAD mode. Tissue ATP and tissue lactate were unaffected by any mode of bypass. Only BIVAD in the asynchronous mode reduced MVO2. When ventricular assist devices are utilized to aid recovery of the natural heart, two devices should always be inserted to allow biventricular assist. Synchronous counterpulsation offers no advantage.

Effect of synchronous and asynchronous pulsatile flow during left, right, and biventricular bypass.

Ventricular assist devices augment aortic or pulmonary flow while the patient's heart recovers from surgery or infarction. Most are used in the asynchronous full-to-empty mode, but they also may be used in a synchronous counter-pulsation mode. This study examines which assist mode optimally reduces myocardial oxygen consumption (MVO2). Eighteen pigs were instrumented with pulmonary artery, carotid artery, and coronary sinus catheters for determination of MVO2. Pierce-Donachy Ventricular Assist Devices (VAD) were used in left, right, or biventricular assist mode. Fifteen minute periods each of control, synchronous, and asynchronous bypass were randomly instituted. The mid-left anterior descending coronary artery was then ligated, and the sequence repeated. At the end of each period, MVO2 was determined. In comparison with controls, MVO2 was statistically significant in the BIVAD asynchronous mode only. Synchronized counterpulsation did not decrease MVO2. When ventricular assist devices are used to aid in cardiac recovery postoperatively or postmyocardial infarction, biventricular assist should be used.