. When it is performed in an aseptic fashion with interpretation taking account of the variables of shunt type, CSF pressure, presence of CSF in the reservoir, and flow pattern, excellent sensitivity and good specificity may be achieved. The test can then usefully augment clinical decision-making in this often difficult area. References 1. Brereton RJ : The value of an ultrasonic flowmeter is assessing the function of CSF shunts. J Pediatr Surg 15 : 68 – 73 , 1980 Brereton RJ: The value of an ultrasonic flowmeter is assessing
Peter Graham, Robert Howman-Giles, Ian Johnston and Michael Besser
Vagn Eskesen, Ebbe B. Sørensen, Jarl Rosenørn and Kaare Schmidt
Treatment: An Introduction to Clinical Decision-Making , ed 2 . Oxford : Black-well , 1981 , pp 21 – 22 Wulff HR: Rational Diagnosis and Treatment: An Introduction to Clinical Decision-Making, ed 2. Oxford: Black-well, 1981, pp 21–22
: Diagnostic tests in normal pressure hydrocephalus. Neurology 23 : 706 – 713 , 1973 Wolinsky JS, Barnes BD, Margolis MT: Diagnostic tests in normal pressure hydrocephalus. Neurology 23: 706–713, 1973 55. Wulff HR : Rational Diagnosis and Treatment: An Introduction to Clinical Decision-Making , ed 2 . Oxford : Blackwell Scientific , 1981 Wulff HR: Rational Diagnosis and Treatment: An Introduction to Clinical Decision-Making, ed 2 . Oxford: Blackwell Scientific, 1981
the latency of the positive response in the absence of a marked alteration in the latency of the negative response indicates that it may be unwise to focus on a single SSEP component only. Accordingly, the presence of an electrical signal should not be equated with the presence of normal SSEP's. Unless quantitative criteria are employed in the description of an evoked response, the use of that response for clinical decision-making is questionable. A final point concerns the use of halothane during the intraoperative monitoring period. The authors state that
Donald A. Ross and Charles B. Wilson
immediate postoperative outcome in 117 patients * Tumor Size (mm) Total Cases No. (%) of Cases With Postop GH Level (ng/ml): < 5 < 10 > 10 Unknown < 10 16 10 (63) 13 (81) 1 (6) 2 10–20 55 37 (67) 47 (85) 3 (6) 5 > 20 46 27 (59) 38 (83) 7 (15) 1 * This table includes only cases for which these data were available. GH = growth hormone. The role of the histological signs of invasiveness in clinical decision-making has not been established, 102, 130 and we do
Sung C. Choi, Raj K. Narayan, Randy L. Anderson and John D. Ward
identifying the optimal set of factors that should be used. However, in less optimal circumstances, physicians have to make difficult decisions pertaining to the most appropriate allocation of limited resources. Simple prediction systems such as this, if used cautiously, may help make this triage process less arbitrary. It must, however, be reemphasized that these predictions are at best intelligent guesses and should be viewed as such, especially if they are considered in the clinical decision-making process. References 1. Becker DP , Miller JD
John R. Robinson, Issam A. Awad and John R. Little
. Other less firm surgical indications include lesions in or near eloquent areas with progressive focal neurological deficits and accessible lesions in women contemplating pregnancy. Conclusions Our study has confirmed the role of MR imaging in the diagnosis and follow-up monitoring of cavernous angiomas, and has provided a profile of the natural history of these lesions including preliminary information about the risk of overt hemorrhage. These have provided general guidelines for rational clinical decision making. Other studies are in progress to further
George T. Tindall, Nelson M. Oyesiku, Nelson B. Watts, Richard V. Clark, James H. Christy and David A. Adams
✓ The results of transsphenoidal adenomectomy for growth hormone (GH)-secreting pituitary adenomas in acromegaly performed over a 17-year period were analyzed retrospectively to determine which preoperative factors significantly influenced the long-term surgical outcome. These variables were then used to develop a logistic regression model to determine the probability of surgical failure.
The series consisted of 103 patients. Long-term follow-up study (mean duration 102 ± 64 months) was performed to derive outcome analysis and determinants of failure. Surgical control was defined as a long-term postoperative serum basal GH level of less than 5 µg/liter, a long-term postoperative serum somatomedin C (SM-C) level of less than 2.2 U/ml, and a favorable clinical response. Eighteen (17.5%) patients did not meet these criteria. The overall control rate by the GH criteria was 81.3% and by the SM-C criteria 76.2%.
By multivariate logistic regression analysis, tumor stage was the strongest predictor of outcome (p < 0.05). The preoperative GH level, tumor grade, and preoperative SM-C level were significant univariate predictors (p < 0.05). There were statistically significant differences in mean preoperative GH and SM-C levels (p < 0.05, t-test) and tumor stage (p < 0.05, chi-squared test) between patients whose acromegaly was controlled by surgery and those whose acromegaly was not. Furthermore, estimates were derived of the probability of surgical failure based on preoperative GH level, preoperative SM-C level, and tumor grade and stage. The authors believe these findings will enhance clinical decision-making for neurosurgeons considering transsphenoidal microsurgery in patients with acromegaly.
Howard Yonas, Holly A. Smith, Susan R. Durham, Susan L. Pentheny and David W. Johnson
, Stringer WA , Marks MP , et al : Stable xenon CT cerebral blood flow imaging: rationale for and role in clinical decision making. AJNR 12 : 201 – 213 , 1991 Johnson DW, Stringer WA, Marks MP, et al: Stable xenon CT cerebral blood flow imaging: rationale for and role in clinical decision making. AJNR 12: 201–213, 1991 13. Kanno I , Uemera K , Higano S , et al : Oxygen extraction fraction at maximally vasodilated tissue in the ischemic brain estimated from the regional CO 2 responsiveness measured by
Marc L. Schröder, J. Paul Muizelaar and A. John Kuta
WD, Busto R, Yoshida S, et al: Histopathological and hemodynamic consequences of complete versus incomplete ischemia in the rat. J Cereb Blood Flow Metab 7: 300–308, 1987 6. Fatouros PP , Schöder ML , Muizelaar JP , et al : Measurement of cerebral blood volume by dynamic contrastenhanced CT and MRI , in Tomonaga M , Yonas H , Tanaka A (eds): Xenon/CT CBF in Clinical Decision Making. Mt Kisco, NY : Futura (In press) Fatouros PP, Schöder ML, Muizelaar JP, et al: Measurement of cerebral blood