Biomedical subjects
Publications and source records attributed to J R Kestle.
This report documents the ability of acute subdural hemorrhage to be easily and completely aspirated percutaneously through the open sutures of infants, obviating the need for open drainage. The technique has recently been used in 4 cases.
Three patients with colloid cysts were identified among approximately 1,400 patients with brain tumors seen at the Hospital for Sick Children in Toronto between 1952 and 1992. These and 34 previously published cases of colloid cysts in children were reviewed. Colloid cysts are rare causes of headaches and papilloedema in children. They usually present with chronic headaches and increased intracranial pressure. Although acute deterioration can occur at any time, it is uncommon. A CT scan or MRI with intravenous contrast is necessary to identify them, particularly those which are isodense. The growth, and subsequent postoperative recurrence of a colloid cyst in 1 youth argues for treatment by complete surgical excision in children.
Ventricular asymmetry is common after ventricular shunting, and occasionally isolation of the contralateral ventricle necessitates a second shunt. The following study was performed to determine whether contralateral placement of the ventricular catheter via ultrasound-guided perforation of the septum pellucidum would decrease the incidence of postshunting ventricular asymmetry which might predispose to symptomatic isolation of a lateral ventricle. Fifty-eight children with hydrocephalus and an open fontanel, who were having a ventriculo-peritoneal shunt via a parieto-occipital approach, were randomized to have the ventricular catheter tip placed into either the ipsilateral or the contralateral frontal horn. Ventricular asymmetry occurred in 23% of the patients with contralateral versus 54% with ipsilateral placement (chi 2 = 5.53; p = 0.019). In 7 patients with contralateral placement, in whom a special catheter with two sets of holes was used, such that holes were located in both ventricles, no shunt-related ventricular asymmetry occurred. In 2 children with ipsilateral placement, a second shunt was required for a symptomatic isolated lateral ventricle. Perforation of the septum pellucidum with placement of the ventricular catheter in the contralateral ventricle, using a specially designed catheter with two sets of holes, may decrease the incidence of postshunting ventricular asymmetry and symptomatic isolation of a lateral ventricle.
To evaluate the reported benefit of ipsilateral single-application ophthalmic anesthetic eyedrops in patients with typical trigeminal neuralgia, a randomized double-blind placebo-controlled trial was performed. Forty-seven patients were randomly assigned to receive two drops of either proparacaine (25 cases) or saline placebo (22 cases). The experimental and placebo groups were equivalent in regard to patient age, distribution of trigeminal neuralgia pain, duration of pain, current medication regimens, and number of prior procedures performed. Pain response was assessed at 3, 10, and 30 days after instillation using two pain rating scales and a measure of pain frequency. Treatment failure was defined in advance as any of the following: a lack of clinical response, the need for an increase in medication, or the need for surgery. No significant difference in outcomes was found between the two groups either when using a verbal pain rating scale (p = 0.24) or when comparing overall pain status (unchanged, improved throughout the study period, or temporarily improved) (p = 0.98). No difference in the frequency of trigeminal neuralgia attacks between the two treatment groups (scaled within five levels of pain frequency) was detected (p = 0.09). During follow-up monitoring, 11 patients in the test drug group and 14 in the placebo group required surgery because of persistent pain (p = 0.24). The results of this study indicate that single-application topical ophthalmic anesthesia reduces neither the severity nor the frequency of pain in comparison to placebo administration. Although a simple and safe treatment, the single application of topical ophthalmic eyedrops provides no short- or long-term benefit to patients with trigeminal neuralgia.
In an attempt to reduce the rate of shunt infection a new protocol for shunt surgery was introduced on July 1, 1988 at The Hospital for Sick Children in Toronto. The operations were done at the beginning of the day, operating room personnel were kept to a minimum, no visitors were allowed in the room, a staff neurosurgeon or neurosurgical fellow attended all operations and two doses of perioperative cloxacillin 50 mg/kg were given intravenously. From July 1, 1988 to June 30, 1989 there were 576 shunt procedures on the Neurosurgical Service and 22 (3.8%) of these resulted in a shunt infection. During the preceding year (July 1, 1987 to June 30, 1988) 581 shunt operations were performed, 75 (12.9%) of which resulted in an infection (chi 2 = 29.9, P < 0.001). It appears that the introduction of this protocol for shunt surgery has helped to reduce the risk of shunt infection from 12.9% to 3.8% (a reduction of 70.5%). The rate of infection occurring after shunt revisions was not significantly different from that occurring after new shunt insertions. When the individual factors in the protocol were analyzed, the use of antibiotics and a shorter duration of surgery appeared to be related to a lower shunt infection rate.
The role of radiotherapy in the management of patients with optic pathway glioma is controversial. In a series of patients with optic pathway glioma treated at The Hospital for Sick Children in Toronto, five children were encountered who developed moyamoya phenomenon after radiotherapy. A retrospective review of the medical records was undertaken in order to assess the relationship between optic pathway glioma, neurofibromatosis type 1 (NF1), radiation therapy, and moyamoya disease. Forty-seven patients with optic pathway glioma were operated on at The Hospital for Sick Children between 1971 and 1990. The moyamoya phenomenon did not occur in any of the 19 patients not receiving radiotherapy. Among the 28 patients who received radiotherapy, five developed moyamoya disease (two of 23 without NF1 and three of five with NF1). There was a statistically significant relationship between radiotherapy and moyamoya disease when the analysis was stratified according to the presence of NF1 (Mantel-Haensel chi-squared test 15.23, p < 0.01). The high incidence of moyamoya disease (three of five cases, or 60%) in patients with NF1 who have undergone radiotherapy suggests a synergistic relationship that should be considered when formulating a treatment plan for NF1 patients with optic pathway glioma.
The postoperative angiograms in 66 patients who underwent craniotomy for clipping of 78 cerebral aneurysms were reviewed. Indications for urgent postoperative angiography included neurological deficit or repeat subarachnoid hemorrhage. Routine postoperative angiograms were carried out in the remaining patients. Postoperative angiograms were reviewed to determine the incidence of unexpected findings such as unclipped aneurysms, residual aneurysms, and unforeseen major vessel occlusions. Logistic regression analysis was used to test if the following were factors that predicted an unexpected finding on postoperative angiography: aneurysm site or size; the intraoperative impression that residual aneurysm was left or a major vessel was occluded; intraoperative aneurysm rupture; opening or needle aspiration of the aneurysm after clipping; or development of a new neurological deficit after surgery. Kappa values were calculated to assess the agreement between some of these clinical factors and unexpected angiographic findings. Unexpected residual aneurysms were seen in three (4%) of the 78 occlusions. In addition, three aneurysms were completely unclipped (4%); these three patients were returned to the operating room and had their aneurysms successfully obliterated. There were nine unexpected major vessel occlusions (12%); six of these resulted in disabling stroke and two patients died. Of six major arteries considered to be occluded intraoperatively and shown to be occluded by postoperative angiography, two were associated with cerebral infarction. Logistic regression analysis showed that a new postoperative neurological deficit predicted an unforeseen vessel occlusion on postoperative angiography. Factors could not be identified that predicted unexpected residual aneurysm or unclipped aneurysm. The inability to predict accurately the presence of residual or unclipped aneurysm suggests that all patients should undergo postoperative angiography. Since a new postoperative neurological deficit is one factor predicting unexpected arterial occlusion, intraoperative angiography may be necessary to help reduce the incidence of stroke after aneurysm surgery. With study of more patients or of factors not examined in this series, it may be possible to select cases more accurately for intraoperative or postoperative angiography.
The spatial accuracy of magnetic resonance imaging (MRI) has not been established for stereotactic surgery. Magnetic susceptibility artifacts may lead to anatomical distortion and inaccurate stereotactic MRI coordinates, especially when targets are in regions of the brain out of the center of the magnetic field. MRI-guided stereotactic localization, however, provides better multiplanar target resolution than is available with computed tomographic (CT) scanning. Therefore, we compared the accuracy of stereotactic coordinates determined by MRI and CT studies in 41 patients (53 targets). Coordinates were measured in each plane and as vector distances between the target and the center of the stereotactic frame on axial or coronal MRI studies. Absolute axial plane MRI and CT distances varied an average of 2.13 +/- 1.59 mm. The mean difference in measurements in the X (left-right) dimension was 1.19 mm and 1.55 mm in the Y (anterior-posterior) dimension. Central targets (located less than 2 cm from the frame center) had a mean MRI-CT difference of 2.09 +/- 1.79 mm; peripheral targets (greater than 2 cm from the frame center) differed by 2.17 +/- 1.3 mm. The voxel volumes were calculated for all compared images. Although differences between the physical properties of data acquisition with each imaging modality could explain the observed CT-MRI discrepancies, a 1-pixel difference in target selection could account totally for all the variance observed. MRI field strength (0.5 vs. 1.5 T) did not correlate with coordinate determination accuracy. We conclude that MRI-guided stereotactic localization can be used with confidence for most diagnostic, functional, and therapeutic stereotactic procedures.
A case of spinal cord infarction resulting from embolization of fibrocartilaginous intervertebral disc material is presented. Cases from the literature are reviewed and the theories of pathogenesis are discussed, in all reported cases the diagnosis was not made until postmortem examination.