Biomedical subjects
Publications and source records attributed to L V Laitinen.
Ventroposterolateral pallidotomy was used in the surgical treatment of 259 patients suffering from intractable Parkinson's disease. Pallidotomy was equally effective against tremor, rigor, bradykinesia, and the L-dopa-induced dyskinesias. The effect of surgery seemed to be long-lasting, and side effects were rare. The author believes that the beneficial effect of pallidotomy is based on interruption of striopallidal and pallidosubthalamic pathways.
Recent laboratory experiments have produced increasing evidence that nigral-striatal dopamine deficiency causes an inhibitory hyperactivity in the medial globus pallidus (MGP), where it freezes the initiation of movement and thus causes bradykinesia, rigidity and tremor. Surgical lesions in the ventroposterolateral (VPL) pallidum in man not only improve the parkinsonian bradykinesia, but also the tremor, rigidity, and the L-dopa-induced dyskinesias disappear or diminish. The present study shows that VPL pallidotomy improves several psychomotor functions, such as walking speed and manual dexterity. Right-sided VPL thalamotomy also increases the speed and accuracy in verbal performance. Ventrolateral thalamotomy increases bradykinesia. The findings support the concept that the parkinsonian symptoms in man develop in the MGP. Intact pathways from MGP via thalamus to the premotor and motor cortex seem necessary for normal motor functioning. The author also discusses the mechanisms of pallidotomy and thalamotomy.
In the treatment of trigeminal neuralgia, the possibility of obtaining a selective effect on different trigeminal branches by glycerol rhizotomy was studied. Transcutaneous electrical stimulation was used to quantify sensory impairment. An attempt was made to obtain a localized neurotoxic effect of the glycerol on the different trigeminal branches by keeping the patient's head in different positions during and for one hour after glycerol injection. The amount of glycerol injected varied according to the estimated size of the trigeminal cistern and/or to which branch that was involved. The study demonstrated a highly selective effect on the ophthalmic branch, less selective on the maxillary, and a low selective effect on the mandibular branch. However, the clinical results were equal regardless of the affected trigeminal division.
Stereotactic ventroposterolateral pallidotomy in 46 parkinsonian patients resulted in a complete or almost complete and long-lasting relief of rigidity and hypokinesia in 91% of the patients. Good tremor effect was obtained in 80% of them. The L-dopa-induced dyskinesias, gait and speech improved in most patients. Complications were observed in 7 cases after 51 pallidotomies, i.e. 14% (partial homonymous hemianopia in 6 and transient dysphasia and facial weakness in 1). We believe that the good effect of surgery is based on interruption of some striopallidal or subthalamopallidal pathways.
Between 1985 and 1990, the authors performed stereotactic posteroventral pallidotomies on 38 patients with Parkinson's disease whose main complaint was hypokinesia. Upon re-examination 2 to 71 months after surgery (mean 28 months), complete or almost complete relief of rigidity and hypokinesia was observed in 92% of the patients. Of the 32 patients who before surgery also suffered from tremor, 26 (81%) had complete or almost complete relief of tremor. The L-dopa-induced dyskinesias and muscle pain had greatly improved or disappeared in most patients, and gait and speech volume also showed remarkable improvement. Complications were observed in seven patients: six had a permanent partial homonymous hemianopsia (one also had transient dysphasia and facial weakness) and one developed transitory hemiparesis 1 week after pallidotomy. The results presented here confirm the 1960 findings of Svennilson, et al., that parkinsonian tremor, rigidity, and hypokinesia can be effectively abolished by posteroventral pallidotomy, an approach developed in 1956 and 1957 by Lars Leksell. The positive effect of posteroventral pallidotomy is believed to be based on the interruption of some striopallidal or subthalamopallidal pathways, which results in disinhibition of medial pallidal activity necessary for movement control.
The relation between postoperative sensory deterioration and surgical outcome in 54 patients treated by retrogasserian glycerol rhizotomy for trigeminal neuralgia was studied. The facial sensibility was assessed one day and three months postoperatively. Thresholds for perception and pain were determined quantitatively using transcutaneous electrical stimulation and clinically by light touch and pinprick tests. At a follow-up one year after surgery there was no significant difference in pain relief between patients who did show and patients who did not show sensory deterioration at the one day or three months evaluations. Nevertheless, there was a tendency for higher recurrence rate in patients with mild or no sensory disturbance.
The possibility of obtaining a selective effect on different trigeminal branches by glycerol rhizotomy was studied in the treatment of trigeminal neuralgia. Transcutaneous electrical stimulation was used to quantify sensory impairment. An attempt was made to direct the neurotoxic effect by maintaining the patient's head in different positions during and after glycerol injection. The amount of glycerol injected varied according to the estimated size of the trigeminal cistern and/or to which branch that was involved. The study demonstrated a good selective effect on the ophthalmic branch, less selective on the maxillary, and a poorly selective effect on the mandibular branch. However, the clinical result following glycerol rhizotomy was equal regardless of the affected trigeminal branch.
A new technique for fractionated stereotactic irradiation of intracranial lesions is described. The treatment is based on a versatile, non-invasive interface for stereotactic localization of the brain target imaged by computed tomography (CT), angiography or magnetic resonance tomography (MRT), and subsequent repetitive stereotactic irradiation of the target using a linear accelerator. The fractionation of the stereotactic irradiation was intended to meet the requirements of the basic principles of radiobiology. The radiophysical evaluation using phantoms, and the clinical results in a small number of patients, demonstrated a good reproducibility between repeated positionings of the target in the isocenter of the accelerator, and a high degree of accuracy in the treatment of brain lesions.
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Nineteen patients with tic douloureux were treated with glycerol injection in the trigeminal cistern. Facial sensibility was measured with an electrical stimulator one day before and one day after the glycerol treatment. The thresholds for perception and pain, and the maximal pain tolerance rose by about 50% (p less than 0.01, 0.01, and 0.001, respectively). The hypaesthesia and hypalgesia were most marked just below the eye, whereas the mandibular division showed only slight sensory impairment. In 13 patients a follow-up sensimetry study was done 1-7 months after surgery. Thirteen patients became completely free of pain and one almost completely free from pain (74%). Two had no pain relief. Twelve patients had no subjective complaints of the treatment. Three reported on dysaesthesiae (16%) over the previously painful area. Seven patients (37%) had subjective sensations of diminished or altered sensibility: numbness and hypalgesia in the face. Corneal hypaesthesia was recorded in ten patients (53%). Glycerol has a non-specific neurotoxic effect which is equal for tactile and nociceptive fibres. Sensory impairment may be a conditio sine qua non for a good clinical result.
A review on indications, target points and results of stereotactic operations for treatment of psychiatric diseases is given, based on personal experiences and reports in the literature. As a conclusion the author suggests that the anatomical target should be chosen selectively. There is strong evidence that different approaches lead to different results. Cingulotomy is effective for chronic pain with addiction and depression, anterior capsulotomy for obsessive-compulsive and anxiety neurosis, innominotomy for chronic and recurrent depression, and postero-medial hypothalamotomy for restless, aggressive and destructive behaviour. Therefore, the target should be selected according to the individual symptoms of the patient. The results of operation are usually good and most patients can return to a normal life. The side-effects are infrequent and seldom serious. Modern psychosurgery does not modify the personality of the patient. On the contrary it often relieves it from disturbing symptoms of illness.
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.
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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.
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.
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)
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.