De novo intracerebral arteriovenous malformations and a review of the theories of their formation.

PURPOSE: Arteriovenous malformations (AVM) are still frequently described as congenital lesions in medical texts despite little evidence existing for their congenital nature. Increasing numbers of case reports of de novo AVMs add weight to the notion that they are dynamic lesions and that they can form postnatally. A thorough review of all reported cases of de novo AVM formation and a review of articles relating to AVM pathogenesis was planned to summarise current research on AVM pathogenesis and provide insight into the future implications for AVM research and treatment. METHODS AND RESULTS: MEDLINE was searched to find 29 cases of de novo AVM formation with prior MRI imaging, nine of which also had prior digital subtraction angiography. A discussion of AVM pathogenesis is undertaken through a review of articles relating to AVM embryology, postnatal angiogenesis, syndromic forms of AVMs and studies of AVM molecular biology and genetics in human and animal models. CONCLUSIONS: There is little evidence for an embryological origin through dysregulated vasculogenesis, whereas there is a raft of evidence to support dysregulated angiogenesis in childhood or even adulthood. Translational implications include risk stratification by biomarkers for predicting haemorrhage and novel therapeutic approaches to suppress AVM proliferation and initiate reversal.

Using telephone logs instead of databases to accurately estimate neurosurgical on-call workload.

BACKGROUND: Maintenance of on-call referrals databases is on the rise in neurosurgical units across the UK and helps provide data to estimate workload. We hypothesize that these databases underestimate the workload and propose the use of the number of telephone calls to the on-call registrar as an easily obtainable and valid measure of workload. METHODS: Data were obtained from a referrals database maintained and completed by the neurosurgical registrars and the hospital switchboard telephone logs. Data were analysed using JMP 8.0.2 (SAS Institute, Cary, NC). RESULTS: We found a large degree of disparity between the number of phone calls and the number of recorded referrals. The median number of phone calls to the on-call registrar per day was 78 (Interquartile range 59-106); but the median number of recorded referrals was 12 (Interquartile range 8-16). 49.8% of the calls were received out-of-hours (1700-0800 and weekends) and the maximum number of calls was received on a Friday. Data derived from both sources (database and switchboard logs) showed a close visual correlation. CONCLUSION: We argue that on-call logs are an easily obtainable, reliable and internally validated measure of activity. We recommend the use of such data in other centers to establish the nature of on-call activity and tailoring of the rotas to comply with current guidance to provide a mix of service and training.

Cervical myelopathy in rheumatoid arthritis.

Involvement of the cervical spine is common in rheumatoid arthritis. Clinical presentation can be variable, and symptoms may be due to neck pain or compressive myeloradiculopathy. We discuss the pathology, grading systems, clinical presentation, indications for surgery and surgical management of cervical myelopathy related to rheumatoid arthritis in this paper. We describe our surgical technique and results. We recommend early consultation for surgical management when involvement of the cervical spine is suspected in rheumatoid arthritis. Even patients with advanced cervical myelopathy should be discussed for surgical treatment, since in our experience improvement in function after surgery is common.

In-vivo measurement of brain relaxation after lobectomies.

Very little data exists on the visco-elastic properties of the living human brain tissue and collection of such data is vital for mechanical modelling. The purpose of this study was to measure the rate of relaxation of brain that has been compressed by tumour after surgical decompression. Seven patients who underwent a lobectomy for an intracranial space occupying lesion were included in the study. All underwent two CT scans within the first 24 h after the surgery. Volumes of the residual void on the serial CT scan were calculated using tools in the image acquisition software. There was a rapid expansion of the brain to fill up the void space in the first 24 h after surgery. The average rate of relaxation of the compressed brain is 2.25(0.76 - 6.64) ml/h. The graphs plotted for the volume of the void space against the time after surgery when the CT scans were done can be used to further explore the dynamics of brain relaxation. The rate of brain relaxation in the first 24 h after removal of a mass lesion averages 2.25(0.76 - 6.64) ml/h in this study. Further studies using more frequent data collection would allow for more accurate definition of the rate of relaxation.

Evaluation of umbilical cord serum therapy for persistent corneal epithelial defects.

AIMS: To evaluate umbilical cord serum therapy as a means of promoting the healing of persistent corneal epithelial defects. METHODS: Umbilical cord serum or autologous serum drops were used to promote the healing of persistent epithelial defects. The study design was a prospective randomised controlled clinical trial. 60 eyes of 59 patients were divided into two groups, 31 in the cord serum group and 29 in the autologous serum control group. Epithelial defects measuring at least 2 mm in linear dimension resistant to conventional medical management were included. Serial measurements of the size of the epithelial defects-namely, two maximum linear dimensions perpendicular to each other, and the area and perimeter was done at start of therapy and follow up days 3, 7, 14, 21. Rate of healing of the epithelial defects were measured as percentage decrease from the baseline parameter at each subsequent follow up. The data were analysed by the non-parametric Wilcoxon rank sum test using STATA 7.0. RESULTS: The median percentage decrease in the size of the epithelial defect was significantly greater in the cord serum group at days 7, 14 and 21 (p<0.05) when measured in terms of the area and perimeter. A greater number of patients showed complete re-epithelialisation with umbilical cord serum (n = 18) than with autologous serum (n = 11) (Pearson chi = 0.19). None of the patients reported any side effects or discomfort with either treatment. CONCLUSIONS: Umbilical cord serum leads to faster healing of the persistent corneal epithelial defects refractory to all medical management compared to autologous serum.

Is axillary temperature an appropriate surrogate for core temperature?

The ideal technique for measuring temperature should be rapid, painless, reproducible and accurately reflect the core temperature. While axillary temperature is commonly used because of convenience and safety, there are conflicting reports about its accuracy. To determine whether axillary temperature can act as a surrogate for oral/rectal temperatures, a prospective comparative study was conducted. The axillary and rectal temperatures (Group 1: infants < 1 year age) and axillary and oral temperatures (Group 2: children 6-14 years age) were compared using mercury-in-glass thermometers. Various tests of agreement were applied to the data obtained. Rectal and axillary temperatures for infants agreed well; the mean difference (95% limits of agreement) between the two being 0.6 degree C (-0.3 degree C, 1.4 degrees C). Similarly, the mean difference (95% limits of agreement) between oral and axillary measurements for children aged 6-14 years was observed to be 0.6 degree C (-0.4 degree C, 1.4 degrees C). Axillary temperature appears to be an acceptable alternative to rectal/oral temperature measurements in children.