Sergio Canavero

Disrupted intrinsic functional connectivity in the vegetative state

It is debatable as to whether the spontaneous blood-oxygen-level dependent fluctuations that are observed in the resting brain in turn reflect consciously directed mental activity or, alternatively, constitute an intrinsic property of functional brain organisation persisting in the absence of consciousness. This report shows for the first time, in three patients, that the persistent vegetative state (PVS) is marked by a dysfunctional default mode network, with decreased connectivity in several brain regions, including the dorsolateral prefrontal cortex and anterior cingulated cortex, especially in the right hemisphere. This finding supports the view that the resting state is involved in self-consciousness, and that the right-hemisphere default state may play a major role in conscious processes. It is speculated that the default state may act as a surrogate marker of PVS with awareness contents and, therefore, could replace a more complex activation paradigm.

Therapeutic extradural cortical stimulation for central and neuropathic pain: a review.

ObjectiveExtradural cortical stimulation is a recent addition to the armamentarium of functional neurosurgery. This article reviews results of treatment of chronic central and neuropathic pain. ConclusionsIt is concluded that extradural cortical stimulation may be effective in several refractory cases.

The neurochemistry of central pain: evidence from clinical studies, hypothesis and therapeutic implications.

&NA; Recent evidence suggests that central pain, i.e., pain due to central nervous system damage, may be due to a deranged neurotransmission between the sensory thalamus and sensory cortical areas. Central pain can be controlled either by opposing glutamate neurotransmission or potentiating GABAergic transmission. It is speculated that a relative hypofunction of the GABAergic inhibition both at thalamic and cortical levels leads to a sectorial excitatory hypertonus in those same areas. A blend of the two should mark each patient. A pharmacological dissection approach is provided that should optimize the treatment, up to now globally poor, of central pain.

Report of a cavernoma of the cauda equina and review of the literature

Subdural intramedullary and extramedullary cavernous angiomas are rare vascular malformations. A case of cavernoma of the cauda equina affecting a 46-year-old man is reported. He presented with low back and sciatic pain. This is the fourth case of cavernoma of the cauda equina in the literature. The available literature on intramedullary (28 cases) and extramedullary (9 cases) cavernomas is reviewed.

Lamotrigine control of central pain.

Central pain remains a therapeutic challenge. We report beneficial effects of lamotrigine, a novel antiepileptic drug, on four patients suffering from long-standing central pain. Analgesia may be due to interference with glutamatergic transmission.

Spinal intramedullary cavernous angiomas: A literature metaanalysis

The present report reviews 57 (out of 65) cases of spinal intramedullary cavernomas collected from the literature, plus one personal patient. Almost 70% of all patients were women. Mean age at diagnosis for women was 36.4 years, with a peak in the third decade. More than three-fourths of all women became symptomatic between the second and fourth decades, with a peak in the fourth decade. Unlike in men, cervical and thoracic lesions are almost equally represented, generally involving 1-2 vertebral levels. Mean size at diagnosis is 1.7 cm; no enlargement over time was seen. Symptoms are more frequently acute; pain and sensorimotor deficits are the usual complaints, but the clinical picture may simulate that of multiple sclerosis. The duration of history was less than 5 years in more than 80% of women. Bleeding was seen in 60% of women, with a risk of 1.6%/person-year of exposure globally. Cervical lesions have both a shorter course and increased frequency of bleeding. If not immediately recognized, repeated cycles of bleeding are the norm, with a mean interval of 39.6 months between the first and second episodes. The preoperative status was the single most important factor bearing on outcome, whereas sex, age, size, location, duration of history and extent of removal were not. Magnetic resonance imaging was diagnostic in all cases, whereas angiography was 100% negative. Surgery should not be a necessary first option, as recovery from the first bleeding is apparently fairly frequent.

Therapeutic extradural cortical stimulation for movement disorders: A review

Abstract Extradural motor cortex stimulation was introduced in 1989 for control of central pain. In recent years this has been found useful in several patients with movement disorders. This paper attempts to bring together all the relevant literature, discuss mechanisms and lay out guidelines for future research and clinical applications.

Propofol analgesia in central pain: Preliminary clinical observations

Propofol, an intravenous general anaesthetic, has been reported to relieve some forms of pruritus at subhypnotic doses. We assessed its effectiveness in 32 patients with several kinds of non-malignant chronic pain, in a placebo-controlled, double-blind study. We found that central pain, but not neuropathic pain, is at least partially controlled by propofol at subhypnotic doses, without major side-effects. In particular, allodynia associated with central, but no neuropathic, pain has been completely controlled. Propofol analgesia leads to renormalization of brain metabolism as seen on single photon emission computed tomography. We conclude that propofol may help in the diagnosis of central pain, particularly in unclear cases, and also in treatment. Possible mechanisms of action are discussed.

Spinal epidural angiolipoma: rare or unreported?

Three cases of spinal epidural angiolipoma, all affecting middle-aged women, are reported. Spinal epidural angiolipomas are considered a separate entity from the more common lipomas involving the same space. Although these tumors are considered very rare, the occurrence of three cases in less than 2 years in the same geographical area raises the question of their frequency. The computed tomographic scan has been misleading in two of our patients, whereas magnetic resonance imaging was highly suggestive. Two of these tumors were apparently exceptional, being lumbar and anterior. The patients were admitted with typical sciatic symptoms; one tumor eroded the vertebral body. Spinal epidural angiolipomas may go unreported because their pathogenetic potential is not fully recognized. We suggest that both magnetic resonance imaging and the operating microscope should have a more significant place in the evaluation and treatment of sciatica.

The role of cortex in central pain syndromes: preliminary results of a long-term technetium-99 hexamethylpropyleneamineoxime single photon emission computed tomography study.

The role of the somatosensory cortex in central pain syndromes is widely questioned. Two recent position emission tomography studies detected a strong activation of the parietal and cingular cortices after brief nociceptive stimuli. On the other hand, a recent single photon emission computed tomography study found no cortical activation in five patients affected by central poststroke pain and algodystrophia. In this study, we present the single photon emission computed tomography findings in five patients suffering from central pain syndromes. Two of these, one with facial postrhizotomy anesthesia dolorosa and the other with central poststroke pain, showed a decrease of blood flow in the parietal lobe, further decreasing after stimulation by nonpainful maneuvers. Our results suggest that somatosensory cortical areas might be involved in the generation of anomalous pain states in some cases of central pain syndromes.