A lesão do trato de Lissauer e do corno posterior da substância cinzenta da medula espinal e a estimulação elétrica do sistema nervoso central para o tratamento da dor por avulsão de raízes do plexo braquial

Abstract

RESUMO -Apoplexia pituitária aguda é fenômeno relativamente raro, mesmo em macroadenomas. No entanto, a presença de áreas necro-hemorrágicas intratumorais nestes tumores que não se relacionam a qualquer sintomatologia aguda parece ser bem mais frequente do que se imaginava na era da tomografia. Com o advento da ressonância magnética estas áreas podem ser facilmente diagnosticadas pré-operatoriamente. Dentre os 40 últimos macroadenomas operados e examinados com RMN, 10 possuíam áreas apopléticas subclínicas em seu interior. Sete destes tumores eram não secretores, 2 secretores de GH e um de prolactina. O quadro clínico incluiu, além daqueles correspondentes à eventual secreção endócrina, perda visual progressiva (sem história de piora abrupta ou rápida) (n=8) e cefaléia (n=3). Após a remoção cirúrgica destes tumores e descompressão do aparato óptico, obtivemos melhora visual em 6 pacientes e em 2 a visão permaneceu inalterada. A cefaléia desapareceu em 2 casos. A presença de áreas apopléticas nestes macrotumores bem como sua ausência em séries de microtumores relatadas na literatura sugere que se relacionam mais ao tamanho do tumor do que ao seu caráter secretor ou não, o que é compatível com a provável natureza (insuficiência vascular) da apoplexia subclínica nesses casos.PALAVRAS-CHAVE: apoplexia, tumores, pituitária, assintomáticos. Asymptomatic apoplexy in pituitary tumorsABSTRACT -Acute pituitary apoplexy is a rare event, even in patients with pituitary macroadenomas. On the other hand, the presence of necrotic/hemorrhagic areas, especially in macroadenomas, seems to be more common than earlier reported in the CT period. After the introduction of MR in the presurgical workup of these patients, these apopleptic areas have been more easily diagnosed preoperatively. Forty consecutive patients with pituitary macroadenomas were studied with high-resolution 1.5 T T1 coronal, sagittal and axial slices over the sellar region. Special attention was paid in the detection of necrotic, cystic and hemorrhagic areas within these tumors. Ten patients had hemorrhagic/necrotic areas within their tumors, without any sign or symptom of acute apoplexy. These areas varied from small (2 mm) to very large (30 mm) ones. Seven patients had non-secreting tumors, 2 GH and 1 prolactin secreting tumors, which is the same profile of secretory pattern for the whole series (40 patients). The clinical picture included (other than that caused by endocrine secretion) slowly progressive (but not acute) visual loss (n=8) and headache (n=3). After surgical decompression of the surrounding structures and visual apparatus, which was facilitated by the presence of the necrotic areas, there was visual improvement in 6 patients and headache resolution in 2. The presence of asymptomatic apopleptic areas in these macroadenomas and their absence in microadenomas as can be seen in the literature suggest that they are related more to the size of the tumor than to its endocrine secretion pattern. This is in agreement with a vascular insufficiency hypothesi...

Invasive treatment to control neuropathic pain

“…It is performed to treat phantom limb pain, pain resulting from actinic plexular neuropathies, cancer and trauma pain, postherpetic neuralgia, myelopathic pain, cauda equina injury and spasticity pain, nervous roots avulsion pain and atypical face neuralgia. It has no satisfactory results in complex regional pain syndrome and in patients with multiple sclerosis-associated pain 15,16 . The procedure decreases hyperactivity of nociceptive pathways of spinal cord ascending tracts because it destroys hyperexcited neurons of SCPH laminae l, II, III, IV, V and VI and Lissauer tract which are involved in facilitation and inhibition mechanisms of SCPH neurons activity, as well as ascending pathways traveling through spinal cord posterolateral quadrant.…”

“…This allows changing the balance between excitatory and inhibitory pathways of deafferented segmental neuronal circuits. Lissauer tract and SCPH injury is more effective and safer when indicated to treat patients with extensive deafferentation areas, such as brachial plexus roots avulsion, actinic plexular neuropathy, segmental pain in paraplegic patients with myelopathy or with cauda equina and conus injury [15][16][17] . General anesthesia and laminectomy are needed for spinal procedure, to expose roots penetration zone correponding to innervation of areas where pain is referred, as well as neighbor rostral and caudal dermatomes.…”

“…Preoperative sensory deficit extension and intensity are systematically increased after Lissauer tract and SCPH injury. Motor deficit, in general mild, is present in approximately 10% of patients submitted to Lissauer tract and SCPH injury [15][16][17] . Discrete and transient posterior cord syndrome homolateral to the injury is initially seen in 2/3 of cases, being permanent in 10% to 30%.…”

“…Recurrent pain after surgery in these cases is different from original pain in 50% of cases. Original burning sensation is replaced by aching, throbbing or cold sensation 6,15 . For phantom pain there is immediate improvement in 50% to 100% of patients soon after procedure and in the long term in 50 to 66%.…”

“…For phantom pain there is immediate improvement in 50% to 100% of patients soon after procedure and in the long term in 50 to 66%. Results seem to be more unsatisfactory to treat amputation stump pain 6,15 . The procedure chronically benefits 45.5% to 80% of patients with traumatic myelopathic pain with good initial results in 85% to 100%.…”