Radioisotope Cisternographic Analysis of Post-operative Subdural Hygroma after Aneurysmal Surgery

Authors analyzed the post-operative subdural hygroma using radioisotope(RI) cisternography in 30 cases following aneurysmal surgery with pterional approach from October, 1995 to March, 1996. Age, CSF flow from basal cisterns, and etent of opening of Liliequist's membrane during operation were significantly related to the development of post-operative subdural hygroma. Computed tomography(CT) scan of brain and RI cisternography were performed in all patients at three weeks following operations. RI diffusion time from the interpeduncular cistern to the cerebral convexity of ipsilateral side with surgically opened Liliequist's membrane was compared with contralateral nonoperated normal side. Diffusion time of ipsilateral side(mean 5.2+/-8.4hr) was faster than that of contralateral one. Age, cerebrospinal fluid(CSF) from basal cistern, and extent of opening of Liliequist's membrane during operation were significantly related to development of post-operative subdural hygroma. Development of subdural hygroma after pterional approach for aneurysmal operations in our series is believed to be caused by stagnation of CSF in the convexity until its absorption into the arachnoid villi. Increased CSF flow from the infratentorial space to the supratentorial space through extensively opened Liliequist's membrane is considered to contribute development of its formation.

Subdural Hygroma Following Pterional Approach for Cerebral Aneurysmal Surgery

The occurrence of subdural hygroma following pterional approach for intracranial aneurysm at Yeungnam University from March 1994 to December 1994 was studied with regard to the patients age, location of aneurysm, preoperative ventricular dilatation, operation time, cortex color, CSF flow, opening degree of Liliequist membrane, dissection degree of sylvian fissure, postoperative intradural air amount and day for mannitol infusion using chi-square test. The following results and conclusions were obtained: 1) Subdural hygroma was observed in 28 of 53 patients(52.8%). 2) The patient's age was significantly related to the occurance of subdural hygroma(p<0.05). 3) CSF flow through the basal cistern was significantly related to the occurrence of subdural hygroma(p<0.05). 4) In cases of good CSF flow, degree of Lilieqist membrane opening was significantly related to the occurrence of subdural hygroma(p<0.05). Preserving of Liliequist membrane will minimize the occurrence of subdural hygroma.

Subdural Fluid Collection after Intracranial Aneurysmal Surgery

The clinical course of subdural fluid collection(SDGC) was studied in 32 cases of patients which underwent craniotomy for intracranial aneurysm and analysed regard to patients' age, sex, degree of initial subarachnid hemorrhage, the operating time of aneurysm, duration to appearance of SDFC from craniotomy, changes of clinical state, disappearance time, site, maximal thickness and changes of SDFC, management and prognosis. The results were summarized as followings. 1) SDFC was found in 33 of 85 patients(38.8%). 2) The older age group had higher incidence of SDFC than the younger age group. 3) The older age grop had thicker SDFC than the younger age group in the maximal thickness of SDFC, and that was statistically significant. 4) The early surgery group of aneurysm had lower incidence of SDFC compared with the delayed surgery group. 5) There were minimal changes of clinical states when SDFC was diagnosed by brain CT. 6) The frontal area was involved in all cases and bilateral involvement was noted in 15 cases(45.5%). 7) Surgical procedures were needed in 8 cases(24.2%) of SDFC, including 2 cases of chronic subdural hematoma. 8) Ventricular dilatation with spontaneous improvement of SDFC were noted in 8 cases(24.2%) and lumboperitoneal shunt for hydrocephalus was needed in only 2 cases of them.

Transient Arterial Stenosis at the Site of Temporary Clipping and Vasospasm Distal to It

The authors studied for 20 operated cases of aneurysm which was able to follow-up examination of Transcranial dopple sean. In these patients, we performed temporary clippings at the proximal sites of aneurysms in 12 cases(TC group) and the other 8 patients wre not performed(non-TC group). Trascranial Doppler and Digital Subtraction Angiography was performed at preoperative and postoperative period at all patients. We found that transient arterial stenosis was detected at the site of prolonged temporary clipping(45 min due to premature rupture) by TCD and DSA in 1 case. It was at the supraclinoid portion of ICA and the patient had single right MCA aneurysm. The preoperative vassopasm had been found in 4 cases, subclinical in 3 cases and transientl motor weakuess in 1 case. The postoperative vasospasm occurred in 6 cases of TC group(2 clinical), and no case in non-TC group. There were 1 case of left A1, 5 cases left M1 and 2 cases of right M1, 3 cases of left ICA and 1 case of right ICA. There was no close relationship between the findings of TCD and DSA, and the spastic range of vasospasm was above 150cm/sec by TCD. Thus temporary clipping tends to increase the incidence of postoperative vasospasm, and rather definite after long duration of its application. The anierial stenosis was transient.

Prognostic Factors in Intracranial Aneurysmal Surgery

A prospective analysis of 80 consecutive operated cases of aneurysm were carried out to know the prognostic factors in intracranial aneurysmal surgery. Analysis of end-results with respect to aneurysmal locations and timing of operation showed that the internal carotid artery aneurysm did not make difference in outcome regardless of the timing of surgical intervention, but anterior cerebral artery, middle cerebral artery, and multiple aneurysm were more poor outcomes in the early surgical group(p<0.05). The more grave initial neurological state showed the worse surgical end-results. The poor results were shown in cases of above 3 mm in thickness of the basal cisternal hemorrhage and/or above 30 ml in volume of the intracerebral hematoma on the brain CT scan. During the operation, no sunkened brain, a spasm of offending artery, premature rupture of aneurysm, and post-operative residual intracerebral hematoma were also adverse effects to the post-operative outcomes.

Neuropsychological Analysis of Operated Intracranial Aneurysms

The mortality rate of aneurysmal surgery had recently been reduced due to modern microsurgical technique and refinement of the timing of operation. Despite recovery without neurological deficits, many patients remain with emotional and psychological sequelae postoperatively. We evaluated 33 patients, operated on intracranial aneurysm for recent 2 years, about quality of life and degree of cognitive function. For proper evaluation of outcome of aneurysmal surgery, in addition to the neurological outcome, psychological aspects must be considered.