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Biomedical subjects

L V Laitinen

Publications and source records attributed to L V Laitinen.

At least 37 records · Page 2Linked to original sources
PubMed1988

Intraoperative electrical stimulation of the brain in patients with obsessive-compulsive neurosis.

Twenty patients with intractable obsessive-compulsive neurosis were operated under local anesthesia. Each patient had a lesion produced in 1 of the 4 brain targets: anterior internal capsule, rostral cingulum, middle cingulum, and genu of the corpus callosum. Before destructive permanent lesions were produced, the target area was stimulated electrically. Stimulation gave subjective or objective reactions in 30% of the patients: diminished anxiety, 3 patients; increased anxiety, 1 patient, and motor responses, 2 patients. None experienced an obsessive reaction to stimulation. The clinical effect of surgery was usually good.

Adult↗
PubMed1987

Noninvasive multipurpose stereoadapter.

A noninvasive adapter for stereotaxis guided by computed tomography and magnetic resonance imaging, which was originally developed for morphological (tumour biopsy) surgery, has also been used for functional stereotaxis (thalamotomy, cingulotomy, hypothalamotomy, dentatotomy, etc.), for stereotactic angiography and for external stereotactic irradiation of brain tumours with a conventional linear accelerator. In addition, it has been applied to the location of subcortical brain tumours for open surgery. Recently, the stereoadapter has been supplied with a phantom base, which permits percutaneous tumour biopsy and ventriculostomy without a stereotactic frame.

Biopsy↗
PubMed1987

Multi-purpose stereoadapter.

A noninvasive adapter for CT-, MRI- and angiography-guided stereotaxis had originally been developed for morphological (tumor biopsy) surgery. Because of its high accuracy it has also been used for functional stereotaxis (e.g., thalamotomy, cingulotomy, hypothalamotomy, dentatotomy) and for external stereotactic irradiation of brain tumors and arteriovenous malformations with a conventional linear accelerator. Additionally, it has been used for locating subcortical brain tumors for open surgery. Recently, the adapter, supplied with a phantom base, has been used for percutaneous tumor biopsy and ventriculostomy without a stereotactic frame.

Equipment Design↗
PubMed1986

[Pre- and postoperative quantitative measures of facial sensitivity in tic douloureux].

Electrical stimulation was used for quantitative assessment of facial sensibility before, during and after percutaneous electrocoagulation of the Gasserian ganglion in 19 patients with tic douloureux. A portable stimulator was of a constant current type, which generated rectangular monophasic pulses of 0,2 ms in length and 100 Hz in frequency. The bipolar electrode consisted of saline-soaked felt discs with a surface of 1 cm2 and an interpolar distance of 1 cm. The thresholds for perception and pain were measured over six regions of each side of the face. Additionally, maximal pain tolerance was measured in the painful area and its corresponding healthy area. Shortlasting intravenous anesthesia with Brietal was given before each electrocoagulation. As soon as the patient began to react to speech, the threshold for pain was measured in the painful and the corresponding healthy area. Preoperatively, the measurements showed that the average threshold for perception was 2,5 mA and for pain 3,5 mA. The average maximal pain tolerance was 10,8 mA. There were no differences between the painful and the healthy sides. Electrocoagulations were stopped when the thresholds for pain in the trigger area had become twice as high as that on the contralateral side. The postoperative measurements showed that the average thresholds for perception and pain had doubled, measuring 4,8 and 8,0 mA, respectively. The average pain tolerance had risen from 10,8 to 22,5 mA. A marked rise of both thresholds was also seen in the ipsilateral areas adjacent to the trigger zone. There was good correlation between a heavy sensory deficit and a favourable clinical result.(ABSTRACT TRUNCATED AT 250 WORDS)

Face↗
PubMed1985

An adapter for computed tomography-guided stereotaxis.

A new, versatile adapter for computed tomography-guided stereotaxis is presented. The instrument consists of a light aluminum frame, which by means of a nasion support and two ear plugs is fixed to the patient's head. Reproducibility of repeated fixations is very high. The adapter is fitted to most stereotactic frames and can be used in all adult patients. Comparison between computed tomography- and ventriculography-guided determinations of thalamic targets showed a mean difference of 0.6 and 0.7 mm for the x and y coordinates, respectively. The z coordinates seldom showed any measurable difference. We now perform all types of stereotactic neurosurgery (tumor biopsy, implantation of depth electrodes, thalamotomy, dentatotomy, cingulotomy, etc.) with computed tomography guidance only. The short-term results in a small number of patients have been at least as good as after conventional ventriculography-guided surgery. In addition to open stereotactic surgery, the adapter is also suitable for external stereotactic irradiation of intracranial targets with a linear accelerator.

Brain↗
PubMed1985

CT-guided ablative stereotaxis without ventriculography.

A new technique is described which permits all types of stereotactic surgery to be done without ventriculography, with CT guidance only. The present series consists of 42 patients who underwent thalamotomy, posteromedial hypothalamotomy, dentatotomy or anterior capsulotomy for movement disorders, chronic pain, spasmodic torticollis or psychiatric illness. Postoperative lesion control with repeated CT showed that the method was accurate. The clinical results were considered to be better than those after previous ventriculography-guided surgery. It is concluded that ventriculography is no longer needed for stereotactic neurosurgery.

Brain Diseases↗
PubMed1985

Brain targets in surgery for Parkinson's disease. Results of a survey of neurosurgeons.

Sixteen neurosurgeons were requested to define their preferred surgical target for treatment of parkinsonism. The scattergram thus obtained showed a great variability among surgeons. Although there was a concentration of targets in the ventrolateral (VL) nucleus of the thalamus, there was a separation by as much as 6 to 7 mm between targets. One surgeon placed the lesion in the subthalamic white matter below the VL nucleus, and two placed it outside the thalamus in the pallidothalamic pathways in Forel's field. It is assumed that successful surgery interrupts the pallidothalamocortical pathways that transmit tremor and rigidity impulses, regardless of which part of the pathways is severed.

Humans↗
PubMed1984

Trigeminus stereoguide: an instrument for stereotactic approach through the foramen ovale and foramen jugulare.

The author describes a new, fully stereotactic instrument for the percutaneous treatment of tic douloureux. The principle is to place the instrument in such a position around the patient's head that the foramen ovale lies at the midpoint for a spherical system consisting of a cylinder part and a 90 degrees arch with an electrode carrier. The foramen can then be reached from a suitable bone-free direction, either through the cheek or inframandibularly. The position of the foramen ovale is calculated from lateral and axial radiograms and defined with x, y, and z coordinates. The instrument can also be used for the percutaneous treatment of glossopharyngeal neuralgia.

Adult↗
PubMed1983

Selective posterior rhizotomy for treatment of spasticity.

In 1976, Fasano, et al., described a new technique of posterior rhizotomy for treatment of spasticity. They stimulated electrically fascicles of the posterior roots in spastic patients and found that some fascicles responded to stimulation with tonic muscle contractions. They cut these fascicles, preserving those with a weaker or no reaction. The present authors have used a fairly similar technique in the treatment of eight patients with spasticity of the legs and one patient with spasticity of the arm: all fascicles of the posterior roots T12-Sl and C6-8, respectively, were stimulated electrically during surgery under general anesthesia. Approximately 60% to 80% of the fascicles responded to stimulation with tonic muscle jerks, and only these fascicles were cut. All nine patients showed a good reduction of spasticity. The residual cutaneous and joint sensation remained unchanged. Motility of the limbs usually improved.

Adult↗
PubMed1979

Emotional responses to subcortical electrical stimulation in psychiatric patients.

Subcortical electrical stimulation was applied to the prospective surgical target area during 158 stereotactic operations in 135 psychiatric patients. The following target areas were studied: rostral cingulum below and in front of the genu of the corpus callosum (52 cases) genu (46) cingululum just above the genu (11) middle cingulum (6) anterior internal capsule (33) subcaudate region, 'substantia innominata' (10 cases). Forty-seven per cent of the cases reacted to stimulation with subjective emotional sensory responses. Stimulation of differ targets had significantly different results. Responses were obtained most frequently from the cingulum and genu, and least frequently from the anterior capsule and subcaudate regions. Stimulation of the rostral cingulum often caused 'negative' responses, i.e. an increase in or the appearance of anxiety and tension (11/15 cases). The opposite was true of the adjacent genu of the corpus callosum; on stimulation of this structure anxiety and tension disappeared or diminished (18/19 cases). Schizophrenic patients experienced such 'positive' responses significantly more often than non-schizophrenics. In non-anesthetized patients autonomic reactions were very rare.

Adolescent↗
PubMed1977

Observations on physiological and psychological functions of the ventral oral internal nucleus of the human thalamus.

Eight patients underwent VOI thalamotomy for spasmodic torticollis or choreoathetosis. The clinical results were disappointing: at follow-up examination 8 months postoperatively, on average, none of the seven patients with torticollis regarded the effect as good. In two there was some long-lasting improvement, but in five the results was nil. One patient with choreoathetosis did not benefit from surgery. Side-effects were frequent but not serious; they included excessive sleepiness, drowsiness, weight increase, deterioration of memory and loss of general activity. Electrical stimulation of the VOI nucleus caused subjective sensations in the neck and shoulder muscles without movements of the head, and autonomic or emotional reactions. An evoked scalp response was recorded in contralateral frontal area 8. As shown by psychological tests, in visuospatial performances there is a preoperative defect, which seems to be specific to spasmodic torticollis. After left VOI thalamotomy both receptive and expressive verbal efficiency were impaired. Visual perception and memory were almost unaffected by VOI thalamotomy.

Adult↗