Interventional Neuroradiology

In vitro experiments to investigate spontaneous polymerisation of n-butyl-2-cyanoacrylate when mixed with non ionic oily contrast medium are reported.

The results suggest an interaction between the mixture components which is unique to one particular batch of Lipiodol Ultrafluid and Histoacryl n butyl cyanoacrylate.

The interaction cannot be reproduced with other batches of Lipiodol Ultrafluid nor with an alternative preparation of n-butyl-2-cyanoacrylate. Implications for the use of the materials in neuro-interventional practice are discussed.

Cerebral thrombo-embolic complications seldom occur during intracranial endovascular therapeutic procedures. Yet, despite a systemic preventive regimen of pre-operative intravenous acetylsalicylic acid and effective systemic heparinisation, we encountered seven complications of this type over a period of five years, a 3.7‰ incidence (7/1858).

Local intra-arterial thrombolysis performed immediately after the thrombo-embolic complication resulted in complete recanalization in five cases and partial recanalization in two. CT scans performed 24 hours after thrombolysis were normal in six of the seven patients. Only one female patient with partial recanalization showed a limited cortical infarct in the parietal distribution of the middle cerebral artery territory.

In all seven cases recanalization of the occluded vessel resulted in a return to the baseline initial neurological status.

This short series demonstrates the usefulness of emergent thrombolysis dealing with the thrombo-embolic complications of angiography or endovascular therapy. These results are in agreement with these experimental data showing that early recanalization can prevent macroscopically visible infarcts.

Exact dose planning for stereotactic radiosurgery was enabled in connection with diagnostic angiography or at the end of an endovascular procedure by simply placing a stereotactic localizing box onto the head of the patient while acquiring PA and lateral angiographic views.

The fiducials engraved on the localizing box enabled the appropriate images to be scaled to the stereotactic space. Regular dose planning was then performed after estimating the size of the patient's head. A prediction of the chances of obliteration and the risks of complication could then be made immediately after the endovascular or diagnostic procedure, and further therapy could be selected much more confidently.

This technique may also be used at centres without facilities for radiosurgical treatment if only the localizing box is available. The images may then be sent for evaluation to a unit with dose planning equipment.

The technique is simple and involves little risk, significantly improving patient management. Digital subtraction angiography was used in this study. A correction algorithm was used to minimize the geometric distortion inherent to the digital technique.

Twenty three patients (18 males) were followed from January 1993 to July 1996 for primary central nervous system malignancy: glioblastoma multiforme (GM) (15 patients), anaplastic astrocytoma (AA) (8 patients). Ninety one cycles (average 4 cycles per patient) of intraarterial chemotherapy (IACH) were administered.

The IACH included: Carboplatin (CBP) 250 mg/m2 and Vepesid (VP16) 150 mg/m2 infusion; both drugs in normal saline, 100 ml and 250 ml, were infused over 15 and 30 min respectively. IACH was repeated every two weeks four or six times according to response to chemotherapy. IACH was preceded by i.v. methylprednisolone 40mg and pure anti-emetic (5HT3 serotonin uptake inhibitors) and subcutaneous daily doses of G-CSF following IACH to prevent neutropenia. The whole treatment required a 24h hospital admission.

The IACH was well-tolerated and toxicity (Miller's grade, WHO) included: two cases of reversible pulmonary embolism (8.6%) three and ten days respectively after therapy (one patient had atrial fibrillation, two cases grade 2 vomiting, two grade 1 anaemia and three grade 3 thombocytopenia (13%).

Response to therapy was evaluated in 21 out of 23 patients, two having not yet received at least four IACH cycles: 4 PRO (3 GM, 1 AA), 15 SD (10 GM, 5 AA) and 2 PR (AA). Seventeen patients responded to IACH (SD + RO) (74%), and the PRs belonged to the AA group. Survival duration was from 16 + to 108 weeks.

IACH with CP and VP16 warrants further studies focussing on drug dose and schedule. A prospective randomized multicentric trial evaluating radiotherapy and systemic chemotherapy plus/minus IACH is currently underway.

In order to evaluate the incidence of soft tissue changes after automated lumbar nucleotomy, a prospective cohort study was performed with follow-up CT within four to six hours after treatment of 97 discs in 88 patients.

The CT scans were normal at 47 levels and abnormal at 50. At 11 levels traces of blood were seen along the trajectory, of which nine were located in the subcutaneous fat, one in the extensor and one in the psoas muscle. Small gas collections were observed at 42 levels. Twenty-one of them were located in the extensor and two in the psoas muscle, seven in the subcutaneous fat, two in the epidural space and ten in multiple locations. The abnormal scans were not associated with clinical symptoms different from those with normal scans.

The results support previous reports indicating that this procedure is associated with low morbidity and complication rates.

In order to evaluate the safety of the internal carotid artery (ICA) occlusion based on our simple tolerance test, we reviewed 142 consecutive tolerance tests. Permanent endovascular ICA occlusion was performed on 99; a tolerance test only was performed on the remaining 43.

Our assessment consisted of: 1) angiographic evaluation of collateral circulations without and with ICA test occlusion, 2) evaluation of clinical tolerance to balloon ICA occlusion for 15–20 minutes. Complications of test and permanent ICA occlusion were retrospectively analyzed.

Complications related to test occlusion occurred in 2 cases (1.4%) without causing permanent deficits. Complications related to permanent occlusion occurred in 16 cases (16%) including 2 technical, 10 temporary (10%) and 4 permanent (4%). Complications were significantly decreased after introduction of stringent postoperative care to prevent hypotension in 1987. Since 1988, we performed 47 permanent ICA occlusion and experienced no technical, 3 temporary (6%) and no permanent complications.

Our method to evaluate tolerance to ICA occlusion is simple and safe. Reliability of the results is comparable to other more complicated methods of assessing ICA occlusion.

The successful therapy of a suboccipital cerebrospinal fluid fistula by the percutaneous introduction of fibrin glue under computed tomographic guidance is described.