✓ The postoperative intracranial pressure (ICP) in 36 patients operated on for cerebral aneurysm following subarachnoid hemorrhage was studied. Not only was the baseline ICP significantly lower in patients whose outcome was assessed as “good” as compared with those patients with a worse outcome at 1 month after surgery, but also the height of the plateau waves and B-waves was significantly less in the patients who did well. The baseline ICP and the height of the B-wave formation were unrelated to the position of the aneurysm. Plateau waves were marginally significantly higher in aneurysms of the anterior communicating artery complex. Neither preoperative hypertension nor the use of antifibrinolytic agents made any difference to postoperative ICP. In patients with cerebral arterial vasospasm found preoperatively on the angiograms, the ICP tended to be lower in the postoperative period than in those without spasm.
Andrew H. Kaye and David Brownbill
Stephen Davis and Andrew H. Kaye
✓ The authors report a case of cerebrospinal fluid (CSF) rhinorrhea in a patient with the empty sella syndrome in whom continuous intracranial pressure (ICP) monitoring revealed intermittent peaks of raised ICP. Following a shunt procedure, ICP reverted to normal and the CSF rhinorrhea ceased for 10 weeks. The sella turcica was packed with muscle after the CSF rhinorrhea recurred.
Andrew H. Kaye and David Wallace
✓ Ventricular drainage systems employing a collapsible plastic bag for fluid collection were postulated to cause an increasing back-pressure produced in part by the elasticity of the bag. This postulate was shown to be correct in an experimental situation. There was a logarithmic rise in cerebrospinal fluid pressure as the bag filled. By increasing the size of the bag, the problem was overcome.
Andrew H. Kaye, John R. Little, Bernadine Bryerton, and Michael Modic
✓ Preoperative intravenous digital subtraction angiography (IV DSA) was compared with the operative findings in 54 patients who underwent a total of 57 carotid endarterectomies, to evaluate the accuracy of preoperative IV DSA in predicting the lesion found at surgery. Four studies early in the series were technically unsatisfactory, leaving 50 patients with 53 procedures for evaluation. Severe carotid artery stenosis was accurately predicted in all cases. Deep ulceration in the absence of severe carotid stenosis was reliably shown by IV DSA, although it was not reliably demonstrated by either IV DSA or carotid angiography if severe stenosis was also present. As severe carotid stenosis or deep ulceration are the major radiological indications for carotid endarterectomy, the authors have found that technically satisfactory IV DSA is an adequate preoperative imaging technique.
Bob S. Carter, E. Antonio Chiocca, Russell Lonser, Andrew H. Kaye, and Nicolas de Tribolet
Andrew H. Kaye, George Morstyn, and David Brownbill
✓ A Phase 1–2 study of high-dose photoradiation therapy was performed in 23 patients with cerebral tumors. Twenty-two patients had high-grade gliomas (13 glioblastomas, six recurrent glioblastomas, two anaplastic astrocytomas, and one recurrent anaplastic astrocytoma) and one had a right frontal metastasis from a carcinoma of the lung. Hematoporphyrin derivative was administered to these patients in a dose of 5 mg/kg and, 24 hours later, they all underwent a craniotomy with radical excision of the tumor. The tumor bed was then irradiated with 630 nm of laser light from either an argon dye laser or a gold metal vapor laser for between 43 and 94 minutes, receiving total doses of 70 to 120 J/sq cm (six cases) or 120 to 230 J/sq cm (17 cases). The temperature of the tumor bed was kept below 37°C by irrigation. Fifteen patients who developed new tumors underwent postoperative radiotherapy (45 Gy in 20 divided doses).
There was no evidence of increased cerebral edema and no other toxicity from the therapy. All patients were discharged from the hospital within 18 days of surgery. Four of seven patients with gliomas have suffered a further recurrence at 12 to 16 weeks, and two of 15 patients with primarily treated gliomas experienced recurrence at 3 and 13 months following therapy. Fifteen patients have had no recurrence of their tumor and are alive and well at a median follow-up period of 7 months (range 1 to 16 months). It is concluded that photoradiation therapy using 5 mg/kg of hematoporphyrin derivative and 630 nm light at doses of up to 230 J/sq cm can be used as an adjuvant to surgery and radiotherapy with no additional complications.
Andrew H. Kaye, George Morstyn, and Michael L. J. Apuzzo
✓ Photoradiation therapy is a form of local treatment that depends on the selective retention of a photosensitizer, such as hematoporphyrin derivative (HpD), by the tumor followed by treatment with light of an appropriate wavelength to activate the sensitizer in the tumor. The selective uptake of HpD by cerebral tumors has been demonstrated both in laboratory animal model studies and in clinical studies, and selective destruction of intracerebral tumors has been demonstrated in animal glioma models. The biological basis for photoradiation therapy and, in particular, the mechanisms for the selective uptake of the sensitizer into the tumor and the destruction of tumor with photoradiation therapy are discussed. Current evidence suggests that singlet oxygen is the major intermediary leading to cell damage, although other radicals such as hydrogen peroxide and hydroxyl radicals may be involved. Other studies suggest that the initial damage is to the blood vessels, and the tumor subsequently undergoes ischemic changes.
Sixty-four patients treated with photoradiation therapy have been reported in the literature. The initial clinical studies were disappointing in their therapeutic effect but these studies often included treatment of recurrent gliomas and low doses of light were used. Technical advances, particularly in laser technology, have enabled more effective photoradiation therapy and the clinical trials are reviewed.
Andrew H. Kaye, J. E. K. Galbraith, and John King
✓ The authors report the case of a patient with benign intracranial hypertension and severe papilledema, who underwent surgery for bilateral optic nerve sheath decompression. No change in the intracranial pressure (ICP) was seen during continuous recording performed before and after the operation. This case supports the contention that the decrease in papilledema and the visual improvements seen following this operation are more likely to be due to decrease in optic nerve sheath pressure than to a generalized decrease in ICP, as suggested by other authors.