Timing, duration, and severity of hyponatremia following pediatric brain tumor surgery*.

OBJECTIVE: To describe the time course, variability, and magnitude of serum sodium changes among children undergoing intracranial tumor surgery. DESIGN: Retrospective cohort study. SETTING: Tertiary children's hospital in Salt Lake City, UT. PATIENTS: Children 0-19 years undergoing first neurosurgical procedure for an intracranial tumor, treated during January 2001 and February 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Three hundred nineteen patients were placed in three exclusive groups based on the lowest serum sodium measurement during admission: 1) severe hyponatremia: serum sodium less than or equal to 130 mEq/L; 2) mild hyponatremia: 131-135 mEq/L; and 3) normal sodium: more than 135 mEq/L. Timing and severity of sodium perturbations were assessed within each group. Hundred thirty-seven patients (43%) had mild hyponatremia, 39 (12%) had severe hyponatremia, and 143 (45%) had normal sodium. After surgery, sodium decreased in all groups with lower averaged concentrations during postoperative days 0-1 and 5-6, although patients with severe hyponatremia had the greatest decline. Nearly 80% of hyponatremic patients had mild hyponatremia prior to development of severe hyponatremia; median time between mild hyponatremia and severe hyponatremia was 1.6 days (interquartile range, 0.4-5.6). Seventy-five percent of patients manifest mild hyponatremia within two postoperative days; however, severe hyponatremia developed later with 75% of patients manifesting severe hyponatremia within six postoperative days. Nine patients had initial severe hyponatremia between days 6 and 20 after surgery. Patients with severe hyponatremia had greater sodium variability with significantly lower nadirs, greater maximum values, and larger decreases within 24-hour periods compared with other sodium groups. Seventy-five percent of children with severe hyponatremia spent more than 4 days with abnormally low sodium values. Among hyponatremic patients, obstructive hydrocephalus and age less than 3.5 years were significant independent risk factors for severe hyponatremia. CONCLUSION: Hyponatremia developed in just over half of children. Young children with hydrocephalus have increased risk of severe hyponatremia. Those with severe hyponatremia need frequent and prolonged monitoring because of risk for repeat sodium changes. Further study is needed to evaluate ideal monitoring and treatment of severe hyponatremia after intracranial tumor surgery.

The incidence of postoperative hyponatremia and associated neurological sequelae in children with intracranial neoplasms.

OBJECT: Intracranial tumors are common pediatric neoplasms and account for substantial morbidity among children with cancer. Hyponatremia is a known complication of neurosurgical procedures and is associated with higher morbidity among neurosurgical patients. The authors aimed to estimate the incidence of hyponatremia, identify clinical characteristics associated with hyponatremia, and assess the association between hyponatremia and patient outcome among children undergoing surgery for intracranial tumors. METHODS: This is a retrospective cohort study of children ranging in age from 0 to 19 years who underwent an initial neurosurgical procedure for an intracranial tumor between January 2001 and February 2012. Hyponatremia was defined as serum sodium ≤ 130 mEq/L during admission. RESULTS: Hyponatremia during admission occurred in 39 (12%) of 319 patients and was associated with young age and obstructive hydrocephalus (relative risk [RR] 2.9 [95% CI 1.3-6.3]). Hyponatremic patients were frequently symptomatic; 21% had seizures and 41% had altered mental status. Hyponatremia was associated with complicated care including mechanical ventilation (RR 4.4 [95% CI 2.5-7.9]), physical therapy (RR 4 [95% CI 1.8-8.8]), supplemental nutrition (RR 5.7 [95% CI 3.3-9.8]), and infection (RR 5.7 [95% CI 3.3-9.5]). Hyponatremic patients had a 5-fold increased risk of moderate or severe disability on the basis of their Pediatric Cerebral Performance Category score at discharge (RR 5.3 [95% CI 2.9-9.8]). Obstructive hydrocephalus (adjusted odds ratio [aOR] 3.24 [95% CI 1.38-8.94]) and young age (aOR 0.92 [95% CI 0.85-0.99]) were independently associated with hyponatremia during admission. Hyponatremia was independently associated with moderate or worse disability by Pediatric Cerebral Performance Category score at discharge (aOR 6.2 [95% CI 3.0-13.03]). CONCLUSIONS: Hyponatremia was common, particularly among younger children and those with hydrocephalus. Hyponatremia was frequently symptomatic and was associated with more complicated hospital courses. Hyponatremia was independently associated with worse neurological outcome when adjusted for age and tumor factors. This study serves as an exploratory analysis identifying important risk factors for hyponatremia and associated sequelae. Further research into the causes of hyponatremia and the association with poor outcome is needed to determine if prevention and treatment of hyponatremia can improve outcomes in these children.

Volumetric injury of the distal femoral physis during double-bundle ACL reconstruction in children: a three-dimensional study with use of magnetic resonance imaging.

BACKGROUND: Double-bundle anterior cruciate ligament (ACL) reconstruction was developed to produce a more "anatomic" reproduction of the anteromedial and posterolateral bundles of the ACL. The purpose of this study was to determine the volume of injury to the physis during double-bundle ACL reconstruction in children with open physes. METHODS: Magnetic resonance images (MRIs) of ten knees of children were converted into three-dimensional models. Computer-aided design/computer-aided manufacturing software placed drill-holes of 6, 7, 8, and 9 mm in diameter in these models, simulating tunnels in the femur used for anatomic double-bundle ACL reconstruction. Computer-aided design/computer-aided manufacturing software was used to calculate the total physeal volume and the volume of physis that was removed by creation of the tunnels. The ratio of the physeal volume that had been removed to the total physeal volume was subsequently determined. RESULTS: With use of 6, 7, 8, and 9-mm-diameter drill-holes in the femur, the average physeal volume removed, as a percentage of the total physeal volume, was 1.5%, 2.0%, 2.5%, and 2.9%, respectively, for the anteromedial tunnels; 2.2%, 2.9%, 3.6%, and 4.2% for the posterolateral tunnels; and 3.7%, 4.8%, 5.7%, and 6.5% for the anteromedial and posterolateral tunnels combined. The volume of physeal damage caused by the posterolateral drill-holes was greater than that produced by the anteromedial drill-holes in all subjects. CONCLUSIONS: Drill-hole placement during ACL reconstruction produces a zone of physeal injury. Double-bundle techniques substantially increase the volume of injury to the physis, which appears to increase the risk of abnormal growth in the distal femoral physis following this surgical procedure.