The comparative impact of video consultation on emergency neurosurgical referrals.

OBJECTIVE: Neurosurgical resources are concentrated in tertiary referral centers, whereas emergencies identified from district general hospitals are traditionally referred by telephone consultation (TC). Recent advances in communication technology offer the alternative options of teleradiology (TR) and video consultation (VC). This study aimed to determine the differences among these three consultation methods on the basis of their process-of-care indicators, clinical outcomes, and cost-effectiveness. METHODS: Patients with emergency neurosurgical conditions (head injury, stroke, and miscellaneous) from a district general hospital were randomized to three different modes of consultation: TC, TR, or VC. Process-of-care indicators (postresuscitation Glasgow Coma Scale score, consultation time required, diagnostic accuracy, and transfer decision and safety), 6-month clinical outcome, and cost-effectiveness of the three consultation modes were correlated. RESULTS: In a 3-year period, 710 patients were recruited and randomized to the three consultation modes (n = 235, 239, and 236, respectively). Demographic and clinical data were comparable. TR and VC showed a definite advantage in diagnostic accuracy over TC (89.1 and 87.7% versus 63.8%; P < 0.001). However, duration of the corresponding consultation process was longer for TR and VC than TC (1.01 and 1.3 h versus 0.70 h). A high failure rate (30%) was noted in VC. Thirty-three percent of patients were transferred to the neurosurgical center after consultation. The difference in consultation modes did not have an impact on transfer rate and safety. There was a trend toward more favorable outcome (61%; P = 0.12) and a reduced mortality (25%; P = 0.025) in TR compared with TC (54 and 34%, respectively) and VC (54 and 33%, respectively). The mean cost per patient in the VC group was slightly higher than the other two groups (TC versus TR versus VC = 14,000 US dollars versus 14,400 US dollars versus 16,300 US dollars, respectively), but the differences were not statistically significant. CONCLUSION: Emergency neurosurgical consultation assisted by TR and VC achieved a higher diagnostic accuracy in comparison with conventional TC. Although VC did not show an advantage over TR in process-of-care indicators, clinical outcome, and cost, it has been proven to be a safe mode of consultation in emergency neurosurgery.

Tissue plasminogen activator expression in meningiomas and glioblastomas.

OBJECTIVES: Enzyme-linked immunosorbent assay (ELISA) and Western blotting techniques were used to investigate and compare the expression of tissue plasminogen activator (tPA) in benign (meningioma) and malignant (glioblastoma) human brain tumours. METHODS: A total of 22 tumour samples comprising 11 meningiomas and 11 glioblastomas with adjacent peritumoural tissue were analysed. RESULTS: The mean tPA content of meningiomas was approximately half that of glioblastomas (55.40 (S.D. 34.58) versus 106.98 (S.D. 43.82) ng/ml, p=0.006). Comparing tPA quantity in tumour and peritumoural tissue, there was a significant difference for meningiomas (55.40 (S.D. 34.58) versus 28.35 (S.D. 22.55) ng/ml, p=0.05), but no difference for glioblastomas (106.98 (S.D. 43.82) versus 84.23 (S.D. 57.39) ng/ml, p=0.32). Comparing tumour with normal brain tissue, there was no difference for meningiomas (55.40 (S.D. 34.58) versus 33.08 (S.D. 21.55) ng/ml, p=0.22), but a significant difference for glioblastomas (106.98 (S.D. 43.82) versus 33.08 (S.D. 21.55) ng/ml, p=0.004). Western blotting showed that in the meningioma group, the molecular weight pattern was constant with a dominant well-defined band at 41kD. Peritumoural tissue demonstrated two bands, with the stronger band at 41kD and a slightly weaker band at 71kD. In the glioblastoma group, there was more heterogeneity, with a dominant 41kD band found in all tumour and peritumoural samples, together with additional bands at 34, 58 and 66kD. CONCLUSION: These results indicate that (1) tPA is present in larger quantities in glioblastoma compared to meningioma and normal brain, (2) tPA quantity is not significantly different in the peritumoural tissue adjacent to glioblastoma but is significantly less for meningioma, and (3) tPA is expressed in more heterogenous forms in glioblastoma. This present study therefore suggests that the expression of tPA in a brain tumour may be an additional prognostic factor in terms of its malignant and invasive potential.

Separation surgery for total vertical craniopagus twins.

OBJECTIVE: A pair of conjoined twins aged 11 months underwent investigations, followed by surgical separation in Singapore General Hospital in April 2001. They were joined at the skull vertex and facing in opposite directions. METHODS: Radiological investigations including cerebral angiography, magnetic resonance imaging and computerized tomographic scans were performed, leading to the diagnosis of total vertical craniopagus. There were two separate brains, with separate arterial circulations, but with a common superior sagittal sinus. Tissue expanders were inserted in the subgaleal space for 6 months of scalp expansion prior to surgery. Pre-operative planning involved the use of virtual reality equipment and life-sized polymer models of the conjoined skulls and brains. Surgical separation of the twins was achieved after approximately 100 h of operating time, using intraoperative image guidance, microsurgical techniques and intraoperative neurophysiologic monitoring. Reconstruction of the dura, calvarium and scalp was performed with artificial dura, absorbable plates and split skin grafts. Postoperative complications included focal cortical infarction, meningitis, and hydrocephalus. CONCLUSION AND OUTCOME: Despite these complications, the twins recovered satisfactorily and were discharged to their home country within 6 months. The 3-month outcome was minor disability in one twin and severe developmental delays in the other. Separation surgery is possible for complex cranially-conjoined twins but requires detailed planning and extensive surgical management.

Advanced "tactile" medical imaging for separation surgeries of conjoined twins.

BACKGROUND: Understanding the anatomy of conjoined twins is difficult because of the rarity of this congenital malformation and the scarcity of reported cases in medical literature. NEW TECHNOLOGY: Advances in radiologic imaging, computer modeling, and sophisticated manufacturing techniques enable medical imaging datasets to be translated into accurate, solid, life-size models. These models, which can be designed to include various combinations of anatomical features revealed by established imaging modalities, are important for pre-surgical assessments and planning, as well as for reference during the actual operative procedure. In addition, they provide a valuable basis for communication between the groups of specialists who are involved in these cases. CASE STUDIES: This article will describe the advances in technology behind this process and illustrate its value in two cases of craniopagus twins.

How useful is glucose detection in diagnosing cerebrospinal fluid leak? The rational use of CT and Beta-2 transferrin assay in detection of cerebrospinal fluid fistula.

BACKGROUND: This report describes the sensitivity and specificity of glucose detection using Glucostix test strips and computed tomography (CT) of the skull base for confirming cerebrospinal fluid (CSF) fistulae in patients with persistent rhinorrhoea or otorrhoea, and comparing them with the beta-2 transferrin assay as the gold standard for CSF detection. METHODS: Fluid samples from the nose were collected from 18 patients with suspected CSF fistulae. The samples were assayed for beta-2 transferrin using the Western blotting and immunostaining technique. CT (5mm axial slice) of the skull base was performed for evidence of skull base fracture. The glucose levels and Glucostix results were compared. RESULTS: Out of the 18 samples, 15 were positive for beta-2 transferrin adn the leaks were validated surgically in 10 patients. Give leaks healed spontaneously with conservative management. Glucostix tests produced three false positive results from blood and nasal mucus contaminated fluid. Glucostix failed to detect another three CSF leaks resulting from false negative tests because of low CSF glucose levels. The Glucostix glucose test was nonspecific and insensitive compared with the beta-2 transferrin assay. CT failed to detect three of the 15 beta-2 transferrin-positive leaks but there were no false positive results. CT produced six negative results, of which three were false negatives. CONCLUSIONS: Glucose detection using Glucostix test strips is not recommended as a confirmatory test due to its lack of specificity and sensitivity. In the presence of a skull bas fracture on CT and a clinical CSF leak, there is no need for a further confirmatory test. In cases where a confirmatory test is needed, the beta-2 transferrin assay is the test of choice because of its high sensitivity and specificity.

Interventional neurophysiologic monitoring.

PURPOSE OF REVIEW: Intraoperative neurophysiologic monitoring provides useful information on the functional status of the nervous system. This review focuses on recently published data concerning the impact of monitoring on patient outcome. RECENT FINDINGS: There is level I evidence to support the use of bispectral index monitoring to prevent awareness during anesthesia in high-risk patients. A number of randomized trials have shown that monitoring-guided anesthesia using the bispectral index or other devices will expedite recovery and improve perioperative drug utilization. There are also preliminary reports suggesting that anesthesia dictated by bispectral index monitoring may alter long-term outcome and reduce mortality. In surgical procedures, however, it is less clear whether neurophysiologic monitoring will improve patient outcome. Currently, the majority of data are derived from respective case series. Nonetheless, monitoring with somatosensory evoked potential has been shown to reduce postoperative neurologic deficits after spinal surgery. There is also evidence to suggest that electromyography and motor evoked potential are essential complements to somatosensory evoked potential for monitoring of spinal cord surgery. SUMMARY: Brain monitoring facilitates anesthetic drug administration. An increasing number of neurosurgical procedures will require some form of intraoperative neurophysiologic monitoring to achieve higher degrees of safety and accuracy. In many instances, the data derived from monitoring will guide and influence surgical decisions. In this context, neurophysiologic monitoring should be regarded as interventional.