Harald Fodstad

Tolerance and tremor rebound following long-term chronic thalamic stimulation for parkinsonian and essential tremor

Fifty-eight patients, 36 with essential tremor (ET) and 22 with Parkinson’s disease (PD), received deep brain stimulation (DBS) in the thalamic ventral intermediate (Vim) nucleus. The mean follow-up was 17 months for ET and 21 months for PD patients. Stimulation parameters were adjusted as needed, at various intervals after surgery. Results were assessed using routine clinical evaluation and established outcome scales. All patients needed incremental increase in stimulation parameters at various intervals during the first 6–12 months after surgery. The mean voltage 1 week postoperatively was 1.45 V in PD patients, and 1.37 V in ET patients. Twelve months later, the figures were 2.14 V in PD and 2.25 V in ET patients. At 1 year, the Essential Tremor Rating Scale (ETRS) improved from 54 to 28 (p < 0.0001). The motor part of the Unified Parkinson’s Disease Rating Scale (UPDRS) improved from 37 to 26 (p < 0.01). Tremor items of the UPDRS improved more markedly (p < 0.0001). One week postoperatively 90% of PD, and 89% of ET patients were tremor free. One year later, 70% of PD and 60% of ET patients remained mostly tremor free. Upon switching off stimulation, there was a clear tendency for tremor rebound (p = 0.07) in the PD group, requiring continuous 24-hour stimulation in some patients. Permanent non-adjustable ataxia was induced by stimulation in 2 PD patients.

Effect of cranioplasty on cerebrospinal fluid hydrodynamics in patients with the syndrome of the trephined

SummaryForty patients with cranial bone defects after craniectomy underwent extensive cerebrospinal fluid (CSF) hydrodynamic investigations by means of a CSF infusion test before and after cranioplasty. The results of these investigations were related to the clinical signs of the patients before and after cranioplasty and to the size and location of the skull bone defect. Twenty-two patients were considered to have “the syndrome of the trephined” (ST). The remaining patients were either free of symptoms or had symptoms not related to ST.CSF hydrodynamic variables that were changed before and normalized after cranioplasty include the following: Resting pressure, sagittal sinus pressure, buffer volume, elastance at resting pressure and pulse variations at resting pressure. The changes were statistically significant mainly in ST patients who were also relieved of their symptoms after cranioplasty.

Do Microelectrode Techniques Increase Accuracy or Decrease Risks in Pallidotomy and Deep Brain Stimulation

Several recent publications have stated that the use of microelectrode recording (MER) during pallidotomy or deep brain stimulation (DBS) contributes to decreasing risks and side effects of surgery, and that such a technique is a prerequisite for minimizing lesion size and for accurate placement of the stereotactic lesion or the DBS electrode. To evaluate the consistency of these statements, we reviewed hundreds of papers and congress reports on MER- and non-MER-guided procedures published since 1992. This review showed that MER groups published more often than non-MER groups. While side effects of surgery were not uncommon in both groups, the rate of severe complications, such as hematoma, and mortality appeared to be higher when microelectrodes were used, both in ablative surgery and in DBS procedures. Besides, the nonaccurate placement of lesions or DBS electrodes, as assessed on published MRI figures, was not uncommon in MER publications. Lesion volume was, when reported, not different in both techniques. The electrical parameters of stimulation of implanted electrodes in the thalamic ventral intermediate (Vim) nucleus for treatment of tremor were higher in MER-guided surgery. The available literature suggests that MER techniques may increase the risks of surgery without enhancing its accuracy, compared to MRI-based macrostimulation techniques. To date, there is no randomized trial by one and the same group on the use of micro- versus macroelectrodes in surgery for movement disorders. A prerequisite for such a trial in the future must imply that the investigators have an equal nonprejudiced attitude towards, and equal confidence and experience in, either technique. Since such a prerequisite does not exist so far in the functional stereotactic community, a critical and comparative study of the available literature remains the only way to evaluate the pros and cons of either technique, in terms of targeting accuracy and surgical complications.

Intracranial aneurysms and heredity

The occurrence of intracranial aneurysms (IAs) in the families of 579 consecutive patients with subarachnoid hemorrhage (SAH), of whom 485 had verified IAs, was studied retrospectively. IAs occurred in the families of 6.7% of the IA patients, but only 0.4% of their siblings had IAs. However, there were differences between the familial and nonfamilial IA patients, indicating that the familial patients are a specific small subpopulation of IA patients. The familial patients were younger, often had multiple aneurysms, and had aneurysms frequently located on arteries other than those in the nonfamilial group.

Fundamental considerations in pacing of the diaphragm for chronic ventilatory insufficiency: A multi-center study

Records were reviewed of 477 patients who had diaphragm pacemakers implanted for treatment of chronic hypoventilation. Three groups were established for comparison. (1) Center group: 165 patients operated on in six medical centers participating in a cooperative study; (2) Noncenter group, sufficient data available: 203 patients operated on by surgeons with experience limited to a few cases; (3) Nonstudy group, minimal data available: 109 patients operated on as in group 2; vital statistics only were contributed. The protocol for data gathering was comprised of 154 major variables. Basic data on age, sex, diagnosis and etiology were analyzed for homogenicity of data among the groups. A comprehensive analysis of the pacing methods, complication and results fom the Center group yielded information on the early experience with diaphragm pacing important to its future application.

Antifibrinolysis with tranexamic acid in aneurysmal subarachnoid hemorrhage: a consecutive controlled clinical trial.

A randomized controlled clinical trial was carried out to study the effect of tranexamic acid (AMCA, Cyklokapron; AB Kabi, Stockholm, Sweden) in the prevention of early rebleeding after the rupture of an intracranial aneurysm. The incidence of vasospasm, hydrocephalus, cerebral ischemic and thromboembolic complications, morbidity, and mortality was also evaluated. The series comprises 59 patients, 30 treated with tranexamic acid and 29 controls. The treatment was stopped if there was rebleeding, operation, or discharge from the hospital. There were 6 recurrent hemorrhages in 6 patients in the tranexamic acid-treated group and 11 recurrences in 7 patients in the control group. Recurrent hemorrhages occurred later in tranexamic acid-treated patients than in controls. Five patients in each group died from rebleeding. Five additional treated patients and 2 controls died from cerebral ischemic dysfunction. The results suggest that tranexamic acid may protect patients with ruptured aneurysms from rebleeding for 1 or 2 weeks, but that it also may produce cerebral ischemic complications.

Treatment of chronic obsessive compulsive states with stereotactic anterior capsulotomy or cingulotomy

SummaryA neuropsychological model on how to evaluate patients subjected to stereotactic psychosurgery is presented. Four patients with chronic obsessive compulsive neurosis were randomly assigned to either Stereotactic anterior capsulotomy or cingulotomy, and assessed pre-, peri-, and postoperatively according to this model. The best immediate and long-term follow-up results in reducing obsessional symptoms were obtained in the two capsulotomized patients.Psychosurgery should only be performed by a multidisciplinary team of specialists, with objective evaluation, adequate information on patients, and reliable test instruments.

Spontaneous thrombosis of ruptured intracranial aneurysms during treatment with tranexamic acid (AMCA). Report of three cases.

SummaryRadiographically verified spontaneous disappearance of medium-sized arterial cerebral aneurysms is seldom reported, and only three times in connection with antifibrinolytic therapy (EACA). In our clinic repeat angiograms have shown non-filling of the aneurysms in three patients during treatment with tranexamic acid (AMCA) two, three, and four weeks respectively after primary bleeds. Initially, all three patients had severe radiological vasospasm associated with neurological deterioration. Follow-up angiograms have demonstrated partial reappearance of the aneurysm after one month in one patient and complete disappearance of the aneurysms in the other two patients after 9 and 22 months respectively. In two cases occlusion of cerebral arteries occurred. With regard to the higher risk of severe vasospasm and occlusion of cerebral arteries in our opinion it should not be a therapeutic goal to try to achieve a thrombosis of a ruptured aneurysm with antifibrinolytic drugs.The reason for spontaneous aneurysm thrombosis during treatment with AMCA may be a local inhibition of plasminogen activators in and around the aneurysm wall. It may also be related to the sympathomimetic property of the drug, with vasospasm and a subsequent flow-reduction inside the aneurysm or a possible interaction with other drugs and substances.

Intractable singultus: A diagnostic and therapeutic challenge

Hiccup or singultus is a repeated involuntary, spasmodic contraction of the diaphragm accompanied by a sudden closure of the glottis mediated by sensory branches of the phrenic and vagus nerves as well as dorsal sympathetic afferents. The principle efferent limb and diaphragmatic spasms are mediated by motor fibers of the phrenic nerve. Hiccup has been classified as a respiratory reflex and the central connection probably consists an interaction among the brainstem respiratory centers, phrenic nerve nuclei, medullary reticular formation and the hypothalamus. Chronic intractable hiccup may be due to brainstem seizures, and baclofen may be the long-awaited remedy for intractable hiccup as demonstrated in three illustrative cases.

Co-existence of abdominal aortic aneurysms and intracranial aneurysms

SummaryThe occurrence of abdominal aortic aneurysms (AAAs) and intracranial aneurysms (IAs) in the same patient and in the same family was studied among 89 patients with AAAs and 485 patients with IAs. Among the AAA-patients two had IAs themselves and five had IAs in the family, whereas three IA-patients had AAAs themselves and eight had AAAs in the family. Moreover, one of the patients with both AAA and IA had a blood relative with AAA, and in six of the families with both types of aneurysms there were more than two subjects with aneurysms. The results indicate, that AAAs and IAs may have a common aetiologic factor.