Microsurgical vascular decompression (MVD) in trigeminal and glosso-vago-pharyngeal neuralgias. A twenty year experience

Report of the results of treatment in 1380 cases with trigeminal neuralgia and 14 cases with glosso-vago-pharyngeal neuralgia. Trigeminal neuralgia was treated by percutaneous thermorhizotomy in 960 cases and by open micro-approach to the cerebellopontine angle in 420 cases. In cases treated by microsurgical vascular decompression, cure rate was 91%, partial relief 5%, failure 4%. Recurrence occurred in 6%. Glossopharyngial neuralgia was treated by percutaneous thermocoagulation of the Andersch ganglion in 3 cases and by a direct approach to the jugular foramen in 11 cases, in 9 of them with micro-vascular decompression. With microsurgical vascular decompression, all cases had total pain relief without recurrence.

Does microsurgical vascular decompression for trigeminal neuralgia work through a neo-compressive mechanism? Anatomical-surgical evidence for a decompressive effect

The positive effect of Microsurgical Vascular Decompression (MVD) on idiopathic trigeminal neuralgia still remains controversial between a decompressive mechanism and a "neo-compressive" one. This paper is a summary of a comparative study of the results on pain obtained with two technical modifications of the MVD procedure. The first consisted of interposition of a foreign material between the nerve and the transposed artery after dissection of the trigeminal nerve, whilst in the second the offending vessel(s) was dislodged without using any material touching the nerve. The two series of 60 patients in each were similar concerning the clinical features. Evaluation of results on neuralgia - with one year follow-up-in both series, shows that the technique used in the second group was not followed by a higher rate of recurrence than the technique used in the first group. On the contrary; 4.5% in the 2nd group compared to 10% in the first. This indicates that MVD would not act as a result of "neo-compression" of the nerve, but rather through a real decompressive mechanism.

Ablative neurosurgical procedures for the treatment of chronic pain

This article is devoted to ablative neurosurgical procedures used for the treatment of chronic pain. The authors detail only those procedures that are currently performed. The procedures are classified as those directed to the peripheral nerves, spinal roots and cranial nerves; the dorsal root entry zone; the ascending extra-lemniscal pathways. The authors have analyzed the results of their own series and those published in the literature. They concentrate on the rationale and neurophysiological effects of the operations.

Microsurgical ablative procedures in the peripheral nerves and dorsal root entry zone for relief of focal spasticity in the limbs

When spasticity is harmful and localized in the limb(s), ablative procedures in the peripheral nerves or the dorsal root entry zone (DREZ) can be useful. The authors report on the long-term results of (1) selective tibial neurotomy in a series of 62 spastic feet, and (2) microsurgical DREZ-tomy in a series of 69 patients affected with hyperspasticity in the entire upper or lower limb(s).

Pericallosal aneurysms

The authors report a series of 19 patients with one (17 cases) or two (2 cases) pericallosal aneurysms referred during the past 10 years. Of the 19 patients, 18 had a ruptured pericallosal aneurysm and one was asymptomatic. On admission two were graded I, four graded II, six graded III, and six graded IV. Of the latter group two patients died from rebleeding, and the asymptomatic patient would not undergo surgery. The 16 operated patients underwent surgery after a delay ranging from 6 to 90 days after hemorrhage (25 days on average). The delayed surgery allowed the patients to be operated on in better neurological status: seven were graded I or Ia, six graded II, three graded III, and none graded IV. The results were excellent (with resumption of their previous activity) in 11 cases (69%), good (autonomous but with a slight deficit) in 4 cases (25%), and bad in 1 case (6%). There was no operative mortality or morbidity.

Selective neurotomy of the tibial nerve for treatment of the spastic foot

One of the most frequent neurological sequelae seen by the specialist in rehabilitation is the spastic foot. Spasticity in the foot may be responsible for abnormal posture and painful or trophic disturbances impairing standing and walking. This disability can be corrected by a simple neurosurgical procedure, the selective tibial neurotomy. In this procedure, one sections the tibial nerve branches to the muscles sustaining spasticity, i.e., the soleus and/or the gastrocnemius nerves for equinus and ankle clonus or the posterior tibialis branch for varus and the flexor fascicles for tonic flexion of the toes. After microsurgical dissection of each tibial nerve branch at the lower part of the popliteal region and their identification with bipolar electrostimulation, the selected branches are partially sectioned under the operating microscope. The present series consists of 62 operations performed in 53 patients, 9 bilaterally and 44 unilaterally. Operation obtained complete suppression of the disabling spasticity that had been present for 2 to 17 years (4 on average), total pain relief, and consequently improvement of the residual voluntary movements (by achieving a better balance between agonist and antagonist muscles) in 51 of the 62 spastic feet (i.e., 82% of the cases). For all of these patients, the beneficial effects were long-lasting over the 1- to 10-year follow-up (3 years on average). Selective neurotomy of the tibial nerve should be considered only after failure of intensive prolonged kinestherapy and of all available medical treatment. It must take place, however, before the onset of irreversible articular disturbances and musculotendinous retractions, which require complementary orthopedic corrections.

Choroid plexectomy for the treatment of chronic infected hydrocephalus

Choroid plexectomy was performed for chronic infected hydrocephalus in 17 children via a direct open approach. In 16 cases, the CSF was sterilized soon after the plexectomy. In 37% of cases, the hydrocephalus was arrested without a shunt. The incidence of seizures did not increase after plexectomy. Removal of the choroid plexus was controlled by scintigraphy. Neuropsychological results were not encouraging, probably related to the long history of chronic ventricular infection. Surgical mortality was 6%. Choroid plexectomy should be considered as a possible treatment of chronic infected hydrocephalus in children.

A simple model of VA/Q distribution for analysis of inert gas elimination data

A general procedure for fitting compartments models of alveolar ventilation-perfusion ratio (VA/Q) distribution to inert gas elimination data is described. The method can be applied to any model consisting of a number of compartments ventilated and perfused in parallel, each compartment of the model having a fixed predetermined VA/Q ratio. The number of compartments and their VA/Q ratios required for adequately fitting real data have been examined. A 13-compartment model consisting of a shunt, a dead space, and 11 compartments equally spaced on a logarithmic scale from VA/Q of 0.01 to 100 was found to be suitable. The fitting procedure and the 13-compartment model form the basis of a method of analysis of inert gas elimination data. Essentially the method consists of calculating a sample of 30 distributions compatible with the data analyzed taking into account experimental errors in the inert gas measurements. From this sample, the averages and standard deviations of the flows to 13 zones on the VA/Q scale are estimated. The averages are estimates of the true flows to these zones, and the standard deviations give an indication of the range of flows compatible with the data. The method has some advantages over both the enforced-smoothing approach and the Monte Carlo linear programming scheme of Evans and Wagner (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 42: 889-898, 1977).

Improvement in ventilation-perfusion matching by almitrine in COPD

Almitrine, a peripheral chemoreceptor stimulating drug, was given 100 mg orally to six patients with advanced chronic obstructive pulmonary disease (COPD), and its effects on hemodynamics, blood gases, lung mechanics, and the distribution of ventilation/perfusion ratios (VA/Q), determined by the inert gas elimination technique, were investigated. Arterial Po2 increased from 52 +/- 4 to 59 +/- 3 mm Hg, mean +/- SEM, p less than 0.01, arterial Pco2 decreased from 46 +/- 3 to 43 +/- 3 mm Hg, p less than 0.05, and venous admixture from 30 +/- 6 to 19 +/- 3 percent, p less than 0.02. No change occurred in ventilation, variables of lung mechanics, systemic and pulmonary hemodynamics, except an increase in pulmonary vascular resistance (from 364 +/- 103 to 438 +/- 99 dyne.s.cm-5, p less than 0.05). A reduction in VA/Q inequality could be demonstrated with a redistribution of blood flow into the lungs by a diversion of 15 percent of total blood flow from units with low VA/Q (between 0.08 and 0.4) to units with normal VA/Q (between 0.5 and 1.8). These changes might be explained by an enhancement of hypoxic pulmonary vasoconstriction. Pharmacologic peripheral chemoreceptor stimulation, at an infra-ventilatory analeptic dosage, might be of therapeutic interest to patients with respiratory insufficiency due to VA/Q inequality.