These are turbulent times for American neurosurgery. It is important to look ahead and prepare for the future but it is also important to look back—for it is memory and tradition that prevent the tyranny of the present. It is impossible to know where we are going if we don’t remember where we were. In this paper I want to discuss the founding principles of neurosurgery—the principles that have allowed neurosurgery to prosper in its first century—and to stress the importance of adhering to these principles in times of change. I also want to talk to you about how the American Association of Neurological Surgeons (AANS) is helping neurosurgeons honor our founding principles, while preparing neurosurgery for its second century.
Robert E. Harbaugh
Ralph F. Reeder and Robert E. Harbaugh
✓ Hyponatremia frequently complicates the care of neurosurgical patients and requires prompt effective therapy. These patients commonly fulfill the laboratory criteria of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) or cerebral salt wasting; the classification depends on the volume status of the patient. The authors have been dissatisfied with the standard therapy of fluid restriction for the critically ill neurosurgical patient because of 1) slow rates of sodium correction; 2) poor applicability in patients requiring multiple intravenous medications and/or nutritional support; and 3) possible dangers of inducing or enhancing cerebral ischemia in patients who already may be fluid-depleted.
Reported successes in the treatment of hyponatremia due to SIADH by administration of urea and normal saline led to the authors' routine use of this therapy for hyponatremic neurosurgical patients. A retrospective review of an 18-month period revealed 48 patients (3% of all neurosurgical inpatients) with hyponatremia from various causes who received 62 treatments of urea and normal saline. Treatment consisted of 40 gm urea dissolved in 100 to 150 ml normal saline as an intravenous drip every 8 hours and an intravenous infusion of normal saline at 60 to 100 ml/hr for 1 to 2 days. The mean pretreatment serum sodium level (± standard deviation) was 130 ± 3 mmol/liter (range from 119 to 134 mmol/liter). There was a significant mean posttreatment elevation to 138 ± 4 mmol/liter (range 129 to 148 mmol/liter) (p < 0.001, Student's t-test). Average daily fluid intake and output on treatment days were 2719 ± 912 and 2892 ± 1357 ml, respectively. There were no treatment complications in this group. It is concluded that urea and saline administration results in a rapid, safe, and effective correction of hyponatremia, making this method superior to fluid restriction in many neurosurgical patients.
Robert E. Harbaugh and Richard L. Saunders
✓ In the neonate, palpation of the anterior fontanel is recognized as a simple and reliable means for estimating intracranial pressure. With closure of the fontanel this aspect of the clinical examination is lost. The authors report a series of 15 shunted infants and children in whom a false fontanel was created by making a 2-cm craniectomy in the right parietal region and excising the underlying internal pericranium. This produces a cranial opening which, like the anterior fontanel, can be used for palpation and real-time ultrasound imaging of the brain. By removing the internal pericranium, reossification of the defect is delayed by more than 12 months. Sparing the dura propria avoids the risks of cerebrospinal fluid leak or brain herniation into the cranial window. This procedure is reported to be simple, reliable, and of value in assessing shunt function in hydrocephalic infants and young children. An illustrative case report is presented.
Robert E. Harbaugh, David W. Roberts and Jonathan D. Fratkin
✓ A 44-year-old woman presented with intraventricular hemorrhage and a calcified avascular mass lesion in the anterior third ventricle. This lesion proved to be a densely calcified variant of cavernous hemangioma, namely, hemangioma calcificans. Twelve previous cases of this lesion have been reported in the neurosurgical literature. Association with spontaneous intraventricular hemorrhage has not been previously reported. The clinical presentation, radiological appearance, surgical findings, and histopathology of this lesion are discussed and a brief review of the literature is presented.
Madhavan L. Raghavan, Baoshun Ma and Robert E. Harbaugh
Object. The authors investigated whether quantified shape or size indices could better discriminate between ruptured and unruptured aneurysms.
Methods. Several custom algorithms were created to quantifiy the size and shape indices of intracranial aneurysms by using three-dimensional computerized tomography angiography models of the brain vasculature. Data from 27 patients with ruptured or unruptured aneurysms were evaluated in a blinded fashion to determine whether aneurysm size or shape better discriminated between the ruptured and unruptured groups. Five size and eight shape indices were calculated for each aneurysm. Two-tailed independent Student t-tests (significance p < 0.05) were used to determine statistically significant differences between ruptured and unruptured aneurysm groups for all 13 indices. Receiver-operating characteristic—area under curve analyses were performed for all indices to quantify the predictability of each index and to identify optimal threshold values. None of the five size indices were significantly different between the ruptured and unruptured aneurysms. Five of the eight shape indices were significantly different between the two lesion groups, and two other shape indices showed a trend toward discriminating between ruptured and unruptured aneurysms, although these differences did not reach statistical significance.
Conclusions. Quantified shape is more effective than size in discriminating between ruptured and unruptured aneurysms. Further investigation will determine whether quantified aneurysm shape will prove to be a reliable predictor of aneurysm rupture.