Climate change projected effects on coastal foundation communities of the Greater Everglades using a 2060 scenario: need for a new management paradigm.

Rising sea levels and temperature will be dominant drivers of coastal Everglades' foundation communities (i.e., mangrove forests, seagrass/macroalgae, and coral reefs) by 2060 based on a climate change scenario of +1.5 °C temperature, +1.5 foot (46 cm) in sea level, ±10 % in precipitation and 490 ppm CO2. Current mangrove forest soil elevation change in South Florida ranges from 0.9 to 2.5 mm year(-1) and would have to increase twofold to fourfold in order to accommodate a 2060 sea level rise rate. No evidence is available to indicate that coastal mangroves from South Florida and the wider Caribbean can keep pace with a rapid rate of sea level rise. Thus, particles and nutrients from destabilized coastlines could be mobilized and impact benthic habitats of southern Florida. Uncertainties in regional geomorphology and coastal current changes under higher sea levels make this prediction tentative without further research. The 2060 higher temperature scenario would compromise Florida's coral reefs that are already degraded. We suggest that a new paradigm is needed for resource management under climate change that manages coastlines for resilience to marine transgression and promotes active ecosystem management. In the case of the Everglades, greater freshwater flows could maximize mangrove peat accumulation, stabilize coastlines, and limit saltwater intrusion, while specific coral species may require propagation. Further, we suggest that regional climate drivers and oceanographic processes be incorporated into Everglades and South Florida management plans, as they are likely to impact coastal ecosystems, interior freshwater wetlands and urban coastlines over the next few decades.

Posterior fossa syndrome: identifiable risk factors and irreversible complications.

Cerebellar mutism was first described by Rekate et al. in 1985 as a transient condition which occurs after posterior fossa operations in children. Posterior fossa syndrome (PFS) and cerebellar mutism are often used interchangeably in the literature. In our experience, we found cerebellar mutism to be a reversible component of a persistent neurologic syndrome. The cause and identifiable risk factors have not been clearly elucidated in the literature. To further characterize PFS, we reviewed 253 children with posterior fossa tumors who underwent surgical resection. We documented 20 cases of PFS (8%), 12 males and 8 females. Age ranged from 1.5 to 13 years (mean = 6.5). Of the 20, 16 were medulloblastoma, 3 ependymoma and 1 astrocytoma. There was a 21 % incidence (16/76) of PFS in medulloblastoma of the posterior fossa. The incidence for ependymoma was 13% (3/24) and 1% (1/102) for astrocytoma. All 20 cases (100%) had brainstem involvement by the tumor. The most frequent postoperative findings included mutism, ataxia, 6th and 7th nerve palsies and hemiparesis. Mutism had a latency range of 1-7 days (mean = 1.7) and a duration of 6-365 days (mean = 69.2, median = 35). Although mutism resolved in all cases, the remaining neurologic complications which characterized our findings of PFS were rarely reversible. We describe potential risk factors for developing PFS after surgery with hopes of making neurosurgeons more aware of potential problems following the removal of lesions in this area. Early recognition of PFS would further promote patient and family understanding and coping with this syndrome.

Surgical outcomes using bioabsorbable plating systems in pediatric craniofacial surgery.

The purpose of this study was to evaluate the surgical outcomes of the 1.5-mm LactoSorb plating system (Walter Lorenz Surgical, Inc., Jacksonville, FL, U.S.A.) used to stabilize the osteotomized calvarial bone in pediatric patients who have undergone craniofacial surgery. The records of 33 consecutive pediatric patients who underwent craniofacial surgery from January 1997 through December 1997 were reviewed. There were 18 male and 15 female patients, and the age ranged from 4 months to 12 years. Patients were followed-up at 1 week, 1 month, 3 months, 6 months, and 12 months after surgery. For those patients reviewed, the following information is included: age, sex, diagnosis, surgical procedures, number and size of LactoSorb plates and screws used in each patient, operative difficulty of the screws and the heat pack, and postoperative complications, including wound healing, palpability, and infection. The LactoSorb plating system was used to stabilize the osteotomized calvarial bones in 33 patients who were diagnosed with: 1) craniosynostosis, 2) hydrocephalus, 3) fibrous dysplasia, or 4) cranial deformation. Orbital rim advancement and anterior cranial vault reshaping were performed in 17 patients. Posterior cranial vault reshaping, orbital rim advancement, and anterior cranial vault reshaping were performed in eight patients. Posterior cranial vault reshaping only was performed in seven patients. Excision of fibrous dysplasia from temporal bone was performed in one patient. One patient had a postoperative wound infection, and LactoSorb plates were palpable postoperatively in four patients. The LactoSorb plating system provided adequate rigidity for stabilizing the osteotomized calvarial bone during surgery and maintained adequate rigidity after surgery during the bone healing period before absorption. This plating system showed satisfactory results in pediatric craniofacial surgery patients.

Fever after craniofacial surgery in the infant under 24 months of age.

A retrospective review was undertaken of 126 consecutive craniofacial procedures involving a transcranial component, performed at the Children's Medical Center at Dallas, between 1990 and 1994. Standard postoperative axillary temperature measurements were recorded until discharge. Age at surgery of less than 24 months correlated very strongly with a postoperative temperature of greater than 38 degrees C (r = -0.92). The incidence of postoperative fever was high in all age groups, yet there was still a significant difference between the group younger than 2 years and the group in which surgery was performed after the age of 2 years across all postoperative temperature ranges, from >38 degrees C to >39.5 degrees C (p < 0.001, chi-square test). The white blood cell count was elevated above the age-related normal in 67 percent of febrile patients. There was no correlation between type or duration of surgical procedure, length of intensive care or hospital stay, or the need for blood transfusion and the development of a significant postoperative fever. There were minor infectious complications in four patients (3 percent), only one of which was a wound problem related to the surgery. All infectious complications were easily identifiable clinically. There was no mortality or serious infections. The development of postoperative fever, and an elevated white blood cell count, is to be expected in pediatric patients undergoing craniofacial procedures. The routine laboratory investigation of postoperative fever in pediatric craniofacial patients under 2 years of age without procedures involving transgression of the paranasal sinuses is not warranted unless there are associated clinical indicators.

Factitious lambdoid perisutural sclerosis: does the "sticky suture" exist?

We report a patient with occipital flattening attributed to lambdoid synostosis on the basis of perisutural sclerosis. The lambdoid suture was patent at surgery and by histology. Specimen radiography showed no perisutural sclerosis. This case questions the validity of peri- sutural sclerosis as a radiographic indicator of impending lambdoid synostosis.

Recurrent medulloblastoma: frequency of tumor enhancement on Gd-DTPA MR imaging.

Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor.

Recurrent medulloblastoma: frequency of tumor enhancement on Gd-DTPA MR imaging.

Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor.

Methotrexate (MTX) concentration in tumors following low-dose MTX.

Methotrexate (MTX) is a folate analog competitive with reduced folates for cellular transport and metabolism. Since the normal plasma folate concentration is only 10(-8) M, we tested the possibility that there may be a saturable uptake of MTX by proliferating tumor tissue at plasma MTX concentrations of only 10(-7) to 10(-6) M. Patients with advanced malignancies, refractory to accepted therapy, were given low-dose oral MTX (30-60 mg/m2 total dose in four to eight divided doses). Tumor tissue was biopsied 18-24 h after the last oral dose of MTX. The concentrations of MTX and its polyglutamated derivatives were measured in these samples. Forty-eight percent of the drug in the tumor samples was present as a polyglutamated derivative.

Effect of meningomyelocele closure on the intracranial pulse pressure.

Intracranial pressure (ICP) was monitored in a 12-year-old child before and after closure of a large, skin-covered meningomyelocele. Significant cerebrospinal fluid pulse pressure augmentation was observed over a spectrum of pressures following sac closure. Linear regression analysis was done to define pulse pressure-ICP relationships before and after surgery, and a significant increase in the regression slope was noted postoperatively. It is suggested that the unoperated meningomyelocele defect served as a shock absorber to dampen the intracranial pulse pressure. Meningomyelocele closure removes this shock absorber effect, resulting in pulse pressure augmentation.

Adverse reactions to vancomycin used as prophylaxis for CSF shunt procedures.

From January to May 1982, 37 children undergoing CSF shunt procedures in two different countries were enrolled in a randomized, double-blind, controlled study to receive vancomycin hydrochloride (15 mg/kg/dose) or placebo (saline) one hour before surgery and again six hours later. Twenty patients received vancomycin, and 17 received placebo. In the 35 cases that could be evaluated, shunt-associated infections developed in three (17%) of 18 patients who received vancomycin and in four (23%) of the 17 placebo recipients. All infections were caused by Staphylococcus species susceptible to vancomycin. A histaminelike rash developed in seven (35%) of 20 patients during vancomycin infusion. It recurred with readministration in one patient and was accompanied by hypotension in another patient. The reactions were not related to too rapid infusion of vancomycin. Because of the adverse reactions to vancomycin, the study was discontinued.

Subtemporal decompressions for shunt-dependent ventricles: mechanism of action.

The literature suggests that subtemporal decompression is an effective treatment for the syndrome of shunt-dependent ventricles because it allows the ventricle to enlarge around the shunt catheter tip. Pre- and post craniectomy ventricular areas were measured from computed tomography scans with a computer digitizing technique in three patients with this syndrome who had undergone four surgical procedures. All patients improved symptomatically following craniectomy. A significant decrease in total ventricular area was noted in all instances. The results suggest that subtemporal craniectomy causes the ventricles to become smaller, not larger. Other possible explanations for the effectiveness of the procedure are discussed.

Functional improvement after spinal surgery for the dysraphic malformations.

Spinal surgery for the various dysraphic malformations is generally indicated to arrest disease progression. The results of the present study suggest that certain clinical conditions and presentations are associated with an exceptionally good surgical prognosis. Sixty-nine procedures were done in 55 patients. The diagnoses included hydromyelia and tethered cord related to diastematomyelia, lipoma, lipomeningocele, previous operation, and thickened filum terminale. The operative results were evaluated for significant functional neurological and urological improvement, as well as for the relief of pain. Pain relief was achieved in 92% of patients with preoperative pain. Significant functional return was seen in 67% of hydromyelia patients. On the other hand, surgical treatment of tethered cord caused improvement in 24% (lipoma) to 46% (thickened filum and diastematomyelia). These results suggest that patients with hydromyelia and patients with a dysraphic malformation and pain have an excellent prognosis after operation. A re-evaluation of the indications for surgery for these patients may be necessary.

Thermoregulatory disorders after removal of a craniopharyngioma from the third cerebral ventricle.

Aspiration and dissection of a cystic tumor from the third ventricle of a 3-year-old child resulted in several hypothalamic symptoms. One of the most persistent and troubling symptoms was marked hyperthermia which could not be traced to an infectious origin. The elevated temperature was not reduced by acetaminophen and there were abnormalities of circadian temperature cycles. In thermal stimulation tests the high body temperature was defended against induced cooling but the body temperature was raised above 40 degrees C without evoking physiological heat-loss responses and thermal discomfort. The unusual thermoregulatory status of this patient is similar to that seen in laboratory animals with hypothalamic lesions and to that observed with certain naturally occurring hypothalamic lesions in man. This dysthermia has been successfully treated with chlorpromazine.

Significance of postshunt ventricular asymmetries.

Ventricular asymmetries after shunt surgery were studied. Right and left ventricular areas from pre-and postoperative computerized tomography scans were measured with a computer digitizing technique, and the respective areas were expressed as a ratio. Measurements were made from the scans of 15 hydrocephalic children selected at random. Ages at surgery ranged from 1 to 101 weeks. The results indicate a significantly greater decrease in ventricular size on the side of the ventricular shunt catheter. Multiple regression analysis showed no relationship between the magnitude of change in ventricular size and either the patients' age orn the time intervals between surgery and follow-up scans. Possible mechanisms for these postshunt ventricular asymmetries are discussed.

Significance of the so-called absorptive reserve in communicating hydrocephalus: a preliminary report.

Twelve patients with communicating hydrocephalus were studied with a servocontrolled lumbar infusion technique to measure net cerebrospinal fluid (CSF) absorptive capacity and resting pressure. Each patient showed a significant absorptive reserve; the rate of CSF absorption exceeded the rate of formation over a physiological range of pressure. The size of the ventricles did not correlate with either the absorptive capacity or the resting pressure parameter, or both. The data suggest that communicating hydrocephalus does not reflect a simple imbalance between the rates of CSF formation and absorption. Other factors must be of etiological importance and are considered in the discussion.