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.

Results by motor cortex stimulation in treatment of focal dystonia, Parkinson's disease and post-ictal spasticity. The experience of the Italian Study Group of the Italian Neurosurgical Society.

Extradural motor cortex stimulation has been employed in cases of Parkinson's disease (PD), fixed dystonia (FD) and spastic hemiparesis (SH) following cerebral stroke. Symptoms of PD are improved by EMCS: results were evaluated on the basis of the UPDRS and statistically analysed. In PD EMCS is less efficacious than bilateral subthalamic nucleus (STN) stimulation, but it may be safely employed in patients not eligible for deep brain stimulation (DBS). The most rewarding effect is the improvement, in severely affected patients, of posture and gait. FD, unresponsive to bilateral pallidal stimulation, has been relieved by EDMS. In SH reduction of spasticiy by EMCS allows improvement of the motor function.

Extradural cortical stimulation for central pain.

Central pain results from a central nervous system injury and represents a challenge for the pain therapist. Human studies have shown that motor cortex stimulation (MCS), i.e. the placement of a stimulating plate on the dura overlying the motor cortex can relieve brain central pain. Studies suggest that MCS directly affects activity in the first and second order somatosensory areas, thalamic nuclei and also inhibits spinal primary afferents and spinothalamic tract neurons. The following factors have been found to predict analgesia by MCS: intact or almost intact corticospinal motor function, mild or negligible sensory loss, absence of thermal sensory threshold alteration within the painful area, positive response to the barbiturate and/or ketamine test, positive response to the propofol test, positive response to transcranial magnetic stimulation (TMS). The targeting of the cortical area is made by anatomical localization by computed tomography (CT), magnetic resonance imaging (MRI), neuronavigation, intraoperative neurophysiological recordings, functional MRI (fMRI), and intraoperative clinical assessment. We perform the procedure under local anaesthesia. We describe in detail our surgical technique and stimulation protocol. Furthermore, we review the most important studies with respect to their results, the observed side effects and complications. The future prospects and likely developments of MCS for central pain are also discussed.

Extradural cortical stimulation for movement disorders.

Extradural cortical stimulation is a recent addition to the armamentarium of operative neuromodulation. Motor cortex stimulation (MCS) is offered by positioning a stimulating plate extradurally on the primary motor cortex. It is a minimally invasive technique that was originally proposed for the control of central neuropathic pain. Currently, its use has been extended to patients with movement disorders. The need for minimally invasive therapies, with low morbidity-mortality which can be applied to patients who are excluded from deep brain stimulation (DBS), led to the first attempt of MCS in Parkinson's disease (PD). Following the demonstration that transcranial magnetic stimulation (TMS) is beneficial in PD, we attempted direct extradural MCS on patients with advanced PD not meeting the criteria for DBS. The mechanisms of action may include "hyperdirect" motor cortex-subthalamic nucleus (MI-STN) input, inhibition, resynchronisation, plasticity changes, interhemispheric transfer of inhibition/excitation and modulation of other cortical areas. In this article, we review the mechanism of action of MCS in movement disorders, the predictive factors of MCS efficacy in PD, the indications, particularly in the elderly who are not suitable for DBS, the adverse effects, and the technique for localization of the central sulcus and for performing the procedure. The future prospects and developments are also discussed.

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

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.

Lamotrigine reduces total postoperative analgesic requirement: a randomized double-blind, placebo-controlled pilot study.

BACKGROUND: Postoperative pain is undertreated. Lamotrigine, a new antiepileptic drug, has analgesic properties in its antisodium and antiglutamatergic effects. It may prevent postoperative pain. This pilot study assessed lamotrigine effects on postoperative pain. METHODS: This was a double-blind, randomized, placebo-controlled pilot study of 30 patients submitted to transurethral prostatectomy under spinal anesthesia and receiving 200 mg of lamotrigine 1 hour before spinal anesthesia. RESULTS: We observed a statistically significant reduction in total analgesic assumption (p < 0.01) and in visual analog scale scores at 2 (p = 0.04), 4 (p < 0.01), and 6 (p = 0.04) hours after operation. CONCLUSIONS: Lamotrigine may be an effective means of reducing postoperative pain.

Pain, muscle spasms and twitching fingers following brachial plexus avulsion. Report of three cases relieved by dorsal root entry zone coagulation.

Three patients who, following partial brachial plexus avulsion, experienced pain, involuntary finger twitching and muscular spasms are reported. Two exhibited cutaneous trigger zones, stimulation of which exacerbated their pain; changes in emotional tone aggravated both the pain and the spasms. Pain would appear to be due not only to deafferentation and scarring of the dorsal horn, but also to an afferent pathological barrage from partially damaged dorsal roots. The pathological sensory barrage may activate metameric interneuronal circuits and produce involuntary movements. Exacerbation of both the pain and the spasms can be explained on the basis of intrinsic properties of these ectopic pacemakers.

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.

Benign recurrence of a pilocytic cerebellar astrocytoma 36 years after radical removal: case report.

A benign recurrence of a cerebellar juvenile astrocytoma was found in a 52-year-old woman 36 years after the initial radical removal, which was performed when she was 16 years of age. To our knowledge, this is the third detailed case report of the late benign recurrence of cerebellar astrocytoma after total removal. The problem of recurrence of cerebellar astrocytoma is reviewed.

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.

Spinal intramedullary subependymomas: case report and review of the literature.

A cervical spinal intramedullary subependymoma in a 53-year-old man is reported, and the relevant literature is reviewed. Spinal cord subependymomas seem to follow a benign course. Radiotherapy should not be administered to these patients. Magnetic resonance imaging, even with enhancement, is not able to distinguish between a subependymoma and the more common ependymoma.

Functional thalamic depression in a case of reversible central pain due to a spinal intramedullary cyst. Case report.

In this report the authors discuss a case of central pain of spinal cord origin due to a spinal thoracic intramedullary cyst. Single-photon emission computerized tomography with technetium-99m hexamethylpropyleneamineoxime showed thalamic hypoperfusion contralateral to the affected leg. Surgical evacuation resulted in total relief of the pain and normalization of the thalamic alteration. The reader can infer from these findings that functional alterations in thalamic processing may be important in the genesis of central pain.

Painful supernumerary phantom arm following motor cortex stimulation for central poststroke pain. Case report.

In this report, the authors describe a case in which the patient began to experience a supernumerary phantom arm after she received motor cortex stimulation for central pain. The patient had a history of right thalamocapsular stroke. It is speculated that the motor cortex activation triggered a response in the patient's parietal lobe, precipitating perception of the phantom limb. To the authors' knowledge this is the first reported case of its kind.

Intravenous subhypnotic propofol in central pain: a double-blind, placebo-controlled, crossover study.

OBJECTIVE: To validate IV subhypnotic propofol, a gamma-aminobutyric acid A (GABA-A) agonist, as a diagnostic test for central pain. METHODS: The efficacy of systemic propofol (0.2 mg/kg IV bolus) was evaluated in a double-blind, placebo-controlled and crossover fashion on both spontaneous ongoing pain and allodynia in 44 patients with chronic central pain of both brain and cord origin. RESULTS: Propofol was significantly superior to the placebo (Intralipid, Kabi Pharmacia) in reducing the intensity of spontaneous ongoing pain for up to 1 hour after the injection: 24 of 44 patients (55%) receiving propofol showed a significant reduction in spontaneous pain, whereas only 6 patients showed this after the placebo. Propofol also significantly reduced the intensity of both mechanical and cold allodynia. In a few cases, only the evoked components were abolished but not the spontaneous pain. In general, the side effects were minimal and consisted mainly of transitory burning upon injection of both propofol and placebo and slight lightheadedness in a few cases. CONCLUSIONS: Systemic propofol induces analgesic effects on all studied components of central pain and highlights the key role of GABA modulation in central pain.

Low-rate repetitive TMS allays central pain.

Only about 50% of central pain patients respond to motor cortex stimulation in the long run. There is a need for prognostic factors. Here we show that propofol test and TMS both predict short-term effect in nine patients with central pain. This may help reduce the number of failures.

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.

Intramedullary spinal ependymal cyst: case report.

A cervical intramedullary spinal ependymal cyst in a 39-year-old man is reported. Diagnosis was made through magnetic resonance imaging. Total enucleation was possible. This is the sixth such reported case.

Spinal intramedullary cavernous angiomas: a literature meta-analysis.

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.

Total eye transplantation for the blind: a challenge for the future.

Blindness is a human and social problem of incalculable weight. In the future, artificial 'bionic' prostheses and retinal grafts could achieve a long-sought cure. Several lines of evidence led to the speculation that a total eye transplantation for the cure of retinal blindness may become feasible in the near future. It is proposed that a brain dead patient's eye, whose retinal viability has been demonstrated with an electroretinogram recording, be transplanted into the blind's voided orbital socket, through a frontoorbitotemporal craniotomy and orbitozygomatic osteotomy. Regenerating optic nerve axons are channeled in a specially constructed guide to the homolateral corpus genicolatum laterale, while the retinal ganglion cells are adequately protected during the regrowth period. Aspects of this paradigm are reviewed and discussed.