Combined use of non-invasive techniques for improved functional localization for a selected group of epilepsy surgery candidates.

Invasive cortical mapping is conventionally required for preoperative identification of epileptogenic and eloquent cortical regions before epilepsy surgery. The decision on the extent and exact location of the resection is always demanding and multimodal approach is desired for added certainty. The present study describes two non-invasive preoperative protocols, used in addition to the normal preoperative work-up for localization of the epileptogenic and sensorimotor cortical regions, in two young patients with epilepsy. Magnetoencephalography (MEG) was used to determine the primary somatosensory cortex (S1) and the ictal onset zones. Navigated transcranial magnetic stimulation (nTMS) was used to determine the location and the extent of the primary motor representation areas. The localization results from these non-invasive methods were used for guiding the subdural grid deployment and later compared with the results from electrical cortical stimulation (ECS) via subdural grids, and validated by surgery outcome. The results from MEG and nTMS localizations were consistent with the ECS results and provided improved spatial precision. Consistent results of our study suggest that these non-invasive methods can be added to the standard preoperative work-up and may even hold a potential to replace the ECS in a subgroup of patients with epilepsy who have the suspected epileptogenic zone near the sensorimotor cortex and seizures frequent enough for ictal MEG.

Headaches after acoustic neuroma surgery.

Headache and depression were studied in patients who had undergone operation for acoustic neuroma. A questionnaire with headache and Beck Depression Inventory scale were sent to 228 patients, of whom 192 (84%) responded. Preoperative headache was reported by 61 (32%) of the respondents (47 migraine and nine tension-type headache) and 122 (64%) respondents had postoperative headache (15 new migraine and four new tension-type headache). The new postoperative headache was chronic (>/=3 months) in 86% and continued at the time of the survey in 55% and presented typically as severe short-lasting attacks provoked by physical stress, bending or coughing. Non-steroidal anti-inflammatory drugs were effective in most cases. Depression (usually mild) occurred in 24% of the respondents, being significantly more common in prolonged postoperative headache patients. The operation doubled the prevalence of headache (from 32% to 64%). Headache after acoustic neuroma operation appears to be a specific subgroup of postcraniotomy headache.

Follow-up of children with cerebral palsy after selective posterior rhizotomy with intensive physiotherapy or physiotherapy alone.

In all 21 children with spastic cerebral palsy (CP) underwent surgery involving selective posterior rhizotomy (SPR), followed by six months intensive physiotherapy (PT). Neurological and physiotherapeutic assessments were made one, three and five years after the operation. The children undergoing surgery were compared to 21 comparison children who took part in a regular physiotherapy programme during the same time period. At the preoperative assessment, the children undergoing surgery were similar to the comparative children in terms of age, sex, type of CP, spasticity of the legs and mean functional scores. The children were selected for SPR on the basis of more than half a year's arrest of motor development, which was the only significant difference to the comparative group. Motor function was measured using two different methods, the Illinois-St Louis Scale and the Gross Motor Functional Classification System (GMFC). Both groups experienced steady development during the five-year follow-up period and no significant differences were observed in the mean functional scores between the groups. We conclude that this comparative study, like most controlled studies, failed to demonstrate any additional effect of SPR on motor development of children with spastic CP. Nevertheless, SPR may contribute to a resumption of motor development in children with arrested motor development despite vigorous conservative therapy. SPR is therefore justified as treatment in selected cases.

Causes of persistent postoperative headache after surgery for vestibular schwannoma.

Our aim was to elucidate the aetiology of persistent postoperative headache, a common sequel for several years after vestibular schwannoma surgery through the retrosigmoid approach. Twenty-seven patients with reported major postoperative headache were tested for vestibular responses and cervico-collic reflexes. The role of local anaesthesia injected into the neck muscle insertions or around the occipital nerves was evaluated. Sixteen patients operated on for vestibular schwannoma, but without headache, and 12 healthy volunteers served as control groups. Vestibular responses and cervico-collic reflexes deteriorated equally in the patients regardless of whether or not they had a postoperative headache. Local anaesthesia did not alter the results. The posturography results were increased among both patient groups. Sumatriptan alleviated pain in nine patients and abolished it completely in one out of these nine patients. Vestibular imbalance or abnormal activation of neck muscles do not explain postoperative headache. Occipital nerve entrapment or neuralgia explains the headache in a few patients. The relatively pronounced sumatriptan effect may, however, suggest a trigeminal nerve mediated cause for postoperative headache.

Postoperative headache after surgery for vestibular schwannoma.

Postoperative headache was studied among 251 patients who underwent operation for vestibular schwannoma. A questionnaire based on the McGill Pain Questionnaire and the Finnish Pain Questionnaire was sent to the patients. Twenty-one expressions describing postoperative headache were extracted with a factor analysis. The pain intensity was expressed on a visual analog scale, and the risk factors for postoperative headache were evaluated. Immediately after the operation, 154 subjects reported headache. Eighty-nine of the patients had had headache before operation, whereas 65 patients experienced headache only after operation. An average of 8.9 years after surgery, 93 patients still reported headache. Headache was a major problem for 27 subjects; 18 of the 27 had suffered from headache before operation. A retrosigmoidal approach, postoperative gait problems, preoperative headache, and small tumor size predicted postoperative problems with headache. When headache is present before operation, it tends to continue after operation, and if headache continues for 1 year, it usually persists without being reduced.

Is hearing preservation worthwhile in vestibular schwannoma surgery?

The purpose of the study was to evaluate the usefulness of hearing preservation in vestibular schwannoma (VS) surgery. Hearing preservation was attempted in 123 of 383 patients operated on during the years 1979 to 1993 at Helsinki University Hospital. Hearing was preserved in 47 cases. Pure-tone averages (PTA) better than 30 dB were found in 12 cases postoperatively. Seventy percent of the patients rated their hearing preservation as valuable or very valuable. Only 8% did not find hearing preservation useful. Postoperatively, tinnitus was present in 62% of the patients, and it was a moderate problem in only 23% of the patients. In only one subject was the tinnitus a handicap that reduced the quality of life. Based on these experiences, we encourage surgeons to continue efforts to preserve hearing in VS surgery.

Vestibular schwannoma surgery and headache.

The aim of the study was to evaluate aetiological factors for postoperative headache after vestibular schwannoma (VS) surgery with respect to asymmetric activation of vestibular reflexes. After surgery, 27 VS patients with persistent postoperative headache, 16 VS patients without headache and 9 healthy controls were examined. The vestibular, cervicocollic and cervicospinal reflexes were evaluated to study whether asymmetric activation of vestibular reflexes could cause headache. The effect of neck muscle and occipital nerve anaesthesia and the effect of sumatriptan on headache were also evaluated. The vestibular function of VS patients with headache did not differ from that of VS patients without headache, but was abnormal when compared to that of normal controls. The cervicospinal and cervicocollic reflexes did not differ in the patient groups. Injection of lidocaine around the operation scar gave pain relief to two patients, and one of them had occipital nerve entrapment. Infiltration of lidocaine deep in the neck muscles in the vicinity of the C2 root did not alleviate headache, but caused vertigo. Nine patients with musculogenic headache got pain relief from supportive neck collars, and two patients with cervicobrachial syndrome got pain relief from manual neck traction. The study shows that asymmetric activation of cervicocollic reflexes does not seem to be the reason for headache. Headache seems to be linked to neuropathic pain, allegedly caused by trigeminal irritation of the inner ear and the posterior fossa, which has recently been linked to vascular pain.

Tinnitus and vestibular schwannoma surgery.

The aim of this study was to evaluate the effect of operation on tinnitus in vestibular schwannoma (VS) patients. Altogether, 251 VS patients who underwent surgery during the years 1979 to 1993 at Helsinki University Central Hospital were included in the study. Information on preoperative tinnitus was collected from previously acquired data and postoperative tinnitus was evaluated. Preoperatively, 62.6% of the patients had experienced tinnitus. Of those with preoperative tinnitus, 47.4% also had it postoperatively, but of those 93 patients without preoperative tinnitus, 39.8% had tinnitus postoperatively. Tinnitus is one of the primary symptoms of VS, together with hearing impairment and disequilibrium. The risk of postoperative tinnitus is almost 40%, and with preoperative tinnitus, the risk is 7.6% higher. In the majority tinnitus was not related to the surgery. Only a few patients had severe problems with tinnitus; difficulty understanding speech was the major complaint.

Magnetoencephalography in presurgical evaluation of children with the Landau-Kleffner syndrome.

PURPOSE: Our aim was (a) to localize the primary epileptogenic cortex for possible multiple subpial transsection in four children with the Landau-Kleffner syndrome (LKS), and (b) to evaluate the impact of magnetoencephalography (MEG) in the localizing process. METHODS: We used EEG to detect the overall epileptiform activity and MEG for selective recording of fissural spikes. The cortical generators of MEG spikes were modeled with dipoles, and their activation order was determined. The voltage distribution, consistent with the earliest MEG sources, was then identified during the course of the patient's EEG spikes to determine the relative timing between stereotypic EEG and MEG spikes and to distinguish the earliest (primary) source area among the secondary ones. RESULTS: In all patients, the earliest spike activity originated in the intrasylvian cortex, spreading in one subject to the contralateral sylvian cortex within 20 ms. Secondary spikes occurred within 10-60 ms in ipsilateral perisylvian, temporooccipital, and parietooccipital areas. A single intrasylvian pacemaker initiated all epileptic activity in two patients, whereas the other two had independent left- and right-hemisphere circuits or focal spikes. MEG source dynamics predicted the results of the methohexital suppression test in two patients and was confirmed by surgery outcome in one patient, in whom all epileptic activity ceased after a small transsection of the sylvian pacemaker. CONCLUSIONS: (a) The intrasylvian cortex is a likely pacemaker of epileptic discharges in LKS, and (b) MEG provides useful presurgical information of the cortical spike dynamics in LKS patients.

Non-surgical treatment of vestibular schwannoma patients.

The aim of the study was to evaluate the course of vestibular schwannoma (VS) when surgery was not attempted. The tumor may be slowly growing and surgery a risk for a patient. Twenty-eight patients out of 390 VS patients during years 1981-1995 were primarily recommended a non-surgical treatment. Another 3 patients refused the operation. Altogether 23 women and 8 men were evaluated. Their age varied from 30.6 to 74.6 years (median 56.7 years). Tumor size varied from 5 to 30 mm (median 15.0 mm) at the beginning of the follow-up. Patients symptoms, condition and other illnesses were recorded. Seven patients had neurofibromatosis 2 (3 of them had one hearing ear), 2 had severe mental problems, 5 patients had their only hearing ear and 11 patients were not recommended an operation because of their age and other illnesses. Patients were controlled with MRI at intervals from 1 to 3 years. The follow-up time varied from 1 to 20 years (median 2.0 years). The average tumor growth rate among unilateral VS patients was 0.035 cm/year and among bilateral tumors the average tumor growth rate was 0.015 cm/year. Two patients were later operated on, one 2 years after diagnosis because of the tumor growth and the other one 4 years after diagnosis-she had refused an operation earlier. Two patients could not be reached. Another patient had tumor growth but because of his illnesses he got a radiation beam instead of an operation. The majority of the patients could live fairly normal lives and required no treatment. Surgery is not the only alternative to VS patients. Wait-and-see policy is also a good alternative to those who have high operation risk or who refuse an operation.

Depression after surgery for acoustic neuroma.

The purpose of this study was to establish the frequency and pattern of depressive disorders after surgery for acoustic neuroma, and to look for associations. Twenty seven patients with acoustic neuroma underwent thorough psychiatric assessment before surgery and at three and 12 months after surgery. Three patients had a depressive disorder in the preoperative assessment. Of the remaining 24 patients, nine (38%) had a depressive disorder at the three month check up. Deterioration of hearing was the only postoperative detriment associated with a depressive disorder (P = 0·024). All nine patients with a depressive disorder were women (P = 0·001), giving them a 69% incidence. None of the patients without preoperative depression required inpatient treatment for depressive disorder, but three patients out of nine still had a depressive disorder 12 months after surgery.

Presymptomatic DNA and MRI diagnosis of neurofibromatosis 2 with mild clinical course in an extended pedigree.

Neurofibromatosis 2 (NF2), a dominantly inherited disorder, typically manifests as bilateral vestibular schwannomas and predisposes to other nervous system tumors. In this study, we present a large pedigree with a benign course of NF2 (mild Gardner type) characterized by slowly growing vestibular schwannomas but few other manifestations. The family was thoroughly investigated with neurologic, ophthalmologic, and neuro-otologic methods including gadolinium-enhanced MRI of the head and spine and DNA linkage analysis. In the clinical analysis of 22 family members, MRI was superior to neuro-otologic methods in the detection of asymptomatic tumors. Based on the DNA linkage analyses we identified the NF2 mutation carriers with a high degree of certainty. These DNA markers (CRYB2, NEFH, D22S268, and D22S280) can also be used for presymptomatic diagnosis in other NF2 families. Early detection of NF2 gene mutation carriers has become possible using linkage analysis in familial NF2. MRI screening of carriers will reveal presymptomatic vestibular schwannomas (and other CNS tumors), making early intervention possible, but an efficient treatment strategy to prevent deafness has not yet been established.

Recovery of the sutured facial nerve after removal of acoustic neuroma in patients with neurofibromatosis-2.

The authors compared the long-term recovery of sutured facial nerves after the removal of 8 neurofibromatosis-2 (NF2)-associated and 22 non-NF2 acoustic neuromas. The patients were from a series of 270 patients operated on for an acoustic neuroma between 1979 and 1989. The assessment was done with a modified House and Brackmann scale from video recordings. At least some facial movement or tone was achieved (Grade 5 or better) in all but three patients, but in none was the recovery excellent. The facial function, judged by the overall appearance in movement, recovered less in patients with NF2 (P = 0.048); a moderately good recovery (Grade 3 or better) was seen in one patient of eight with NF2, as compared with 13 of 22 with non-NF2. In conclusion, if the tumor cannot be peeled off easily from the facial nerve in patients with NF2, leaving a fragment of tumor behind is preferable to cutting and suturing the facial nerve.

Randomised, controlled study of intratumoral recombinant gamma-interferon treatment in newly diagnosed glioblastoma.

The effect of intratumoral recombinant interferon gamma (rIFN-gamma) as adjuvant to open cytoreduction and external irradiation of 60 Gy on survival in adults with a newly diagnosed high-grade cerebral glioma was studied. The patients were randomised during surgery into the rIFN-gamma group (n = 14) or the control group (n = 17), and the latter received a subcutaneous reservoir of rIFN-gamma injections. Intratumoral rIFN-gamma was given three times a week for 4 weeks until radiotherapy, escalating the dose from 5 micrograms to 50 micrograms. Both groups received external whole-brain irradiation of 40 Gy and a local boost of 20 Gy. After radiotherapy, rIFN-gamma was continued with 50 micrograms twice a week up to 9 weeks. The patients received no chemotherapy. Intratumoral rIFN-gamma was tolerated well with transient fever only. There were 12 glioblastomas (GBs) in the control group and nine in the rIFN-gamma group with completed irradiation. The patients were followed clinically and by computerised tomography (CT) every third month until death. Tumour responses were seen in three interferon-treated (one still alive 45 months after operation) and in two conventionally treated patients. The progression of the tumour volumes on CT did not differ between the IFN-treated and control groups. There were no differences in the survival times. Median survival of the rIFN-gamma-treated patients was 54 weeks (95% CI 35-68) and of the control patients 55 weeks (95% CI 41-77). Intratumoral rIFN-gamma given in the study doses does not seem to inhibit tumour growth or improve the prognosis of patients with high-grade glioma.

Interface between the facial nerve and large acoustic neurinomas. Immunohistochemical study of the cleavage plane in NF2 and non-NF2 cases.

In acoustic neurinoma surgery, the surgeon is required to find a cleavage plane between the facial nerve and the tumor, and with the aid of the operating microscope this is usually achieved by fine dissection. A histological specimen of the nerve-tumor interface is available only if the facial nerve was hopelessly adherent to the tumor (usually a large or giant neoplasm) and the surgeon decided to sever the nerve to obtain a complete removal. The authors have examined immunohistochemically the nerve-tumor interface of 20 such facial nerves (six cases of neurofibromatosis 2 (NF2) and 14 of non-NF2) in a series of 351 acoustic neurinomas. The largest extrameatal dimension of the 20 tumors ranged from 20 to 51 mm (median 39 mm). In all of these 20 instances the nerve-tumor contact area was at least partially devoid of a clear-cut histological cleavage plane. Where the facial nerve trunk was attached to the surface of the tumor, nerve fibers of the contact areas either abutted directly against tumor cells or nerve fibers were seen to penetrate into the tumor tissue. Frank embedding of nerve fibers was more frequent in NF2.

The site of impulse generation in transcranial magnetic stimulation of the facial nerve.

The facial nerve can be stimulated in its intracranial course through transcranial magnetic stimulation (TMS). We studied the site of impulse generation produced by TMS by comparing the latencies of the muscle evoked potentials (MEPs) elicited with TMS and intracranial electrical stimulation (IES) of the facial nerve during neurosurgical posterior fossa procedures. In a series of 25 patients, the mean latency of the TMS elicited MEPs, recorded in the orbicularis oris muscle, was 5.0 ms (SD 0.58). Also IES of the distal part of the facial nerve in the internal acoustic meatus showed a mean latency of 5.0 ms (SD 0.68). Proximal IES in the root entry zone of the facial nerve, and intermediate IES between root entry zone and meatus, produced MEPs with significantly longer latencies compared to TMS and distal IES (p < 0.05). The findings suggest that the TMS induced facial nerve activation, leading to a MEP response, takes place within the internal acoustic meatus.

Craniotomy infections.

The incidence of craniotomy infections, usually less than 5%, is dependent on many factors, such as how the information is collected and how the percentage is calculated. Because these factors may vary from report to report, incidence figures should be read with skepticism. It is difficult to prove that a given factor contributes to infection. Most routines are based more on personal convictions than on solid evidence. CSF leak is one factor known to have great impact; it should be avoided with painstaking technique and, if it occurs, it should be treated promptly. Solid evidence favoring prophylactic antibiotics for persistent CSF leak is not available; but, until a well-designed randomized study tells otherwise, the high risk of meningitis justifies prophylaxis. Penicillin is adequate for leaks through the nose or the ear. For leaks through the skin, the antibiotic should be effective against staphylococci. The infection register should provide information about prevailing bacteria. In many hospitals, the prophylaxis should cover gram-negative bacilli. CRP is a useful diagnostic aid for detecting postoperative infections. The operation, however, also causes a CRP rise. Daily CRP monitoring, at least for patients with elevated temperature, is recommended. The third-generation cephalosporins are a welcome contribution to the treatment of bacterial meningitis. To avoid side effects, and to keep them potent when they are really needed, they should be used with caution. Most postoperative cases of meningitis are in fact aseptic. If the patient is moderately ill, chloramphenicol is still eligible as the first choice antibiotic. When the bacterial culture is negative, the antibiotic should be stopped. The standard treatment for bone flap infection is removal of the bone flap. The bone flap is essentially devascularized and comparable to a foreign body. The justification of vancomycin prophylaxis has been shown in a randomized study.

Functional results of facial nerve suture after removal of acoustic neurinoma: analysis of 25 cases.

The facial nerve is sometimes severed during the removal of acoustic neurinomas, either intentionally to ensure complete removal, or unintentionally because of difficulties in identification. In such cases we have, if possible, sutured the nerve stumps microsurgically, either end to end or by use of an intervening nerve graft. We analyzed the outcome of 25 instances of facial nerve suturing in a series of 219 patients operated on for acoustic neurinoma from 1979 to 1987. The first signs of recovery appeared at an average of 12 months, and there was continued improvement for several years. Recovery was graded from 1 to 6. The anastomosis was successful in 24 of the 25 sutured nerves, in that at least some facial movement and tone were restored (Grade 5 or higher). In 11 of the 25 cases, facial appearance at rest and with movement was moderately good (Grade 2 or 3). A Grade 1 result, with no perceivable facial dysfunction, was never achieved. Typically, oral muscles showed the most improvement and frontal muscles the least. Facial appearance was better at rest than with movement, which was always complicated by some degree of synkinesis. Closure of the eye was so good in 13 of the 25 cases that neither tarsorrhaphy nor an eyelid spring was necessary. When the facial nerve is severed, intraoperative suture is recommended, because it provides a chance for moderately good restoration of facial appearance.