Surgical Treatment for Spasticity: Selective Dorsal Rhizotomy ­ Technique and Literature Review

Spasticity is amotor disorder that leads to a resistance to passive jointmovement. Cerebral palsy is the most important cause of spasticity and can be caused by several factors, including multiple gestations, alcoholism, infections, hemorrhages, drowning, and traumatic brain injuries, among others. There aremany scales that help tomeasure andmonitor the degree of impairment of these patients. The initial treatment should focus on the causal factor, such as tumors, inflammation, degenerative diseases, hydrocephalus, etc. Subsequently, the treatment of spastic musculature includes oral or intrathecal myorelaxants, spinal cord electrostimulation, neurotomies, Lissauer tract lesion, dentatotomy and selective dorsal rhizotomy. The latter is a safetechnique, possibleto beperformed inmost centers with neurosurgical support, and it is effective in the treatment of severe spasticity. In this article, the authors describe the surgical technique and conduct a review the literature.

Ultrasound-Guided DREZotomy: Technical Note.

Dorsal root entry zone (DREZ) lesioning is still used as a choice of treatment for some painful conditions as well as spasticity in selected patients. The most commonly used techniques to perform DREZotomy are the microsurgical one and DREZ radiofrequency (RF) coagulation. The technical difficulties using punctures to perform RF lesions include complications such as occurrence of lesions in the dorsal columns or in the corticospinal tract. This paper describes a new technical improvement in RF lesions at DREZ using intraoperative ultrasound (US) to optimize the lesions and to minimize the risk of complications. Using intraoperative US after laminotomy allows the surgeon to differentiate between the gray matter of the spinal cord and white matter, showing the correct entry zone, the angle to introduce the RF electrode, and the depth. Using intraoperative US to guide DREZ lesions provides real-time optimization of DREZotomy.

Perioperative care in brain arteriovenous malformations / Cuidados perioperatórios em malformações arteriovenosas encefálicas

The authors provide a review of brain arteriovenous malformations, initially reviewing epidemiological and etiological aspects in addition to the pathophysiology and risk factors associated with bleeding. The emphasis of this review is directed to the clinical and care should be taken since the diagnosis of this pathology, intraoperative management on the viewpoint of the anesthesiologist to the potential complications that occur after resection of the lesion.

Os autores realizam uma revisão sobre malformações arteriovenosas encefálicas, revisando inicialmente aspectos etiológicos e epidemiológicos, além da fisiopatologia e de fatores relacionados com risco de sangramento. A maior ênfase dessa revisão é direcionada para o quadro clínico e para os cuidados que devem ser tomados desde o diagnóstico dessa patologia, o manejo intraoperatório sob o ponto de vista do anestesista, até as possíveis complicações que ocorrem após a ressecção da lesão.

The clip-wrap technique in the treatment of intracranial unclippable aneurysms.

UNLABELLED: Fusiform and dolichoectatic aneurysms are challenging lesions to treat with direct clipping. Treatment of these aneurysms often requires alternative surgical strategies, including extracranial-intracranial bypass, wrapping, or clip-wrap techniques. Nonetheless, these alternatives methods of treatment have been underused and frequently overlooked. OBJECTIVE: To report a series of nine cases of otherwise untreatable aneurysms managed using the clip-wrap technique and discuss its surgical nuances. METHOD: In the last four years, 9 cases of ruptured aneurysms treated by the clip-wrap techniques were identified in the Division of Neurological Surgery, University of São Paulo, School of Medicine. RESULTS: The aneurysms were located at middle cerebral artery (2), anterior choroidal artery (1), anterior communicating artery (1), carotid ophthalmic (3), posterior cerebral artery (1) and posterior-inferior cerebellar artery (1). Three were dolichoectatic, 4 were unsuitable to complete surgical clipping because parent or efferent vessels arises from the aneurysm sac (1 MCA, 1 AcomA, 1 CO, 1 PICA aneurysms) and two, although ruptured aneurysms, were too small (<2mm) to be directly clipped. No early or late rebleeding was observed after 2 years mean follow-up. One patient deceased due to pulmonary tromboembolism. CONCLUSION: Clip-wrap techniques for the treatment of fusiform and otherwise unclippable aneurysms seem to be safe and it can be associated with a low rate of acute or delayed postoperative complications. It can prevent rebleeding and represents an improvement when compared with the natural history.

The clip-wrap technique in the treatment of intracranial unclippable aneurysms / Técnica de "clip-wrap" no tratamento de aneurismas rotos não clipáveis

Fusiform and dolichoectatic aneurysms are challenging lesions to treat with direct clipping. Treatment of these aneurysms often requires alternative surgical strategies, including extracranial-intracranial bypass, wrapping, or clip-wrap techniques. Nonetheless, these alternatives methods of treatment have been underused and frequently overlooked. Objective: To report a series of nine cases of otherwise untreatable aneurysms managed using the clip-wrap technique and discuss its surgical nuances. Method: In the last four years, 9 cases of ruptured aneurysms treated by the clip-wrap techniques were identified in the Division of Neurological Surgery, University of São Paulo, School of Medicine. Results: The aneurysms were located at middle cerebral artery (2), anterior choroidal artery (1), anterior communicating artery (1), carotid ophthalmic (3), posterior cerebral artery (1) and posterior-inferior cerebellar artery (1). Three were dolichoectatic, 4 were unsuitable to complete surgical clipping because parent or efferent vessels arises from the aneurysm sac (1 MCA, 1 AcomA, 1 CO, 1 PICA aneurysms) and two, although ruptured aneurysms, were too small (<2mm) to be directly clipped. No early or late rebleeding was observed after 2 years mean follow-up. One patient deceased due to pulmonary tromboembolism. Conclusion: Clip-wrap techniques for the treatment of fusiform and otherwise unclippable aneurysms seem to be safe and it can be associated with a low rate of acute or delayed postoperative complications. It can prevent rebleeding and represents an improvement when compared with the natural history.

Aneurismas fusiformes são lesões de difícil tratamento e frequentemente necessitam de técnicas alternativas de tratamento, incluindo anastomose extra-intracranial ou técnicas de "clip-wrap". Contudo o uso destas técnicas é frequentemente esquecido e negligenciado. Objetivo: Descrever retrospectivamente casuística de nove casos de aneurismas não clipáveis tratados com a técnicas de "clip-wrap" e discutir as nuances cirúrgicas. Resultados: Revisão dos últimos quatro anos da casuística da Divisão de Clínica Neurocirúrgica do HCFMUSP mostrou que 384 casos eram de aneurismas rotos. Destes, 9 eram de aneurismas não clipáveis tratados com a técnica de "clip-wrap". Destes, 2 aneurismas eram de artéria cerebral media, 1 de artéria coroidéia anterior, 1 de artéria comunicante anterior, 3 de artéria oftálmica, 1 de artéria cerebral posterior e 1 de PICA. Três eram lesões ectásicas, 4 não puderam ser completamente clipados devido a relação de aneurismas com vasos eferentes, aferentes ou perfurantes, e dois, apesar de rotos eram pequenos demais para serem clipados (<2,0 mm). Sangramento precoce ou tardio não foram observados, em um seguimento médio de 2 anos. Conclusão: A técnica descrita é segura e está associada com baixa incidência de complicações agudas ou tardias. Ela previne ressangramanto e representa um avanço em relação à história natural destas lesões.

Edema pulmonar neurogênico: [revisão] / Neurogenic pulmonary edema: [review]

O Edema Pulmonar Neurogênico (NPE) é definido como o surgimento agudo de dispnéia ou queda da razão PaO2/FiO2após lesão no sistema nervoso central (CNS), na ausência de outra causa de lesão pulmonar. A causa mais importante de NPE é a hemorragia subaracnóidea (SAH), seguida por trauma de crânio e epilepsia. A incidência de NPE após SAH na literatura pode variar de quatro a 23% nos principais estudos,com 43 a 73% correspondentes à SAH. É postulado que a descarga adrenérgica excessiva levaria o pulmão à vaso constrição e rápido aumento na pressão hidrostática capilar pulmonar, promovendo perda de fluidos para o espaço alveolar.O NPE é geralmente tratado de maneira conservadora,com suporte ventilatório, com foco no tratamento da causa primária da lesão.

Comparative study between ischemic preconditioning and cerebrospinal fluid drainage as methods of spinal cord protection in dogs.

OBJECTIVE: This study compares the effects of immediate ischemic preconditioning based on somatosensory evoked potential (SSEP) monitoring with those of cerebrospinal fluid drainage in a model of descending thoracic aorta occlusion in dogs. METHOD: Eighteen dogs were submitted to spinal cord ischemia induced by descending thoracic aortic cross-clamping for 60 minutes. The Control Group underwent only aortic cross-clamping (n=6). The Ischemic Preconditioning Group (IPC) underwent ischemic preconditioning (n=6) and the Drainage Group underwent cerebrospinal fluid drainage (n=6), immediately before aortic cross-clamping. An independent observer assessed neurological status according to the Tarlov score. The animals were sacrificed and spinal cord harvested for histopathologic study. RESULTS: Aortic pressure before and after the occluded segment was similar in the three groups. Seven days after the procedure, Tarlov scores were significantly higher only in the Drainage Group when compared to the Control Group (p<0.05). Lower SSEP recovery times were also observed with cerebrospinal fluid drainage during the final reperfusion period (p<0.01). In the histopathologic study, stain showed less significant neuronal necrosis in the thoracic and lumbar gray matter in animals submitted to both methods of spinal cord protection, with it being more pronounced in the Ischemic Preconditioning Group (p<0.001). CONCLUSION: Cerebrospinal fluid drainage and immediate ischemic preconditioning seems to protect the spinal cord during descending thoracic aorta cross-clamping. Nevertheless, the obtained level of spinal cord protection seems to be more significant with cerebrospinal fluid drainage.

Ischemic preconditioning and spinal cord function monitoring in the descending thoracic aorta approach.

OBJECTIVES: To evaluate the effectiveness of acute ischemic preconditioning (IP), based on somatosensory evoked potentials (SSEP) monitoring, as a method of spinal cord protection and to asses SSEP importance in spinal cord neuromonitoring. METHODS: Twenty-eight dogs were submitted to spinal cord ischemic injury attained by descending thoracic aorta cross-clamping. In the C45 group, the aortic cross-clamping time was 45 min (n=7); in the IP45 group, the dogs were submitted to IP before the aortic cross-clamping for 45 min (n=7). In the C60 group, the dogs were submitted to 60 min of aortic cross-clamping (n=7), as in the IP60 group that was previously submitted to IP. The IP cycles were determined based on SSEP changes. RESULTS: Tarlov scores of the IP groups were significantly better than those of the controls (p = 0.005). Paraplegia was observed in 3 dogs from C45 and in 6 from C60 group, although all dogs from IP45 group were neurologically normal, as 4 dogs from IP60. There was a significant correlation between SSEP recovery time until one hour of aortic reperfusion and the neurological status (p = 0.011), showing sensitivity of 75% and specificity of 83%. CONCLUSION: Repetitive acute IP based on SSEP is a protection factor during spinal cord ischemia, decreasing paraplegia incidence. SSEP monitoring seems to be a good neurological injury assessment method during surgical procedures that involve spinal cord ischemia.

Pré-condicionamento isquêmico e monitorização da função medular na abordagem da aorta torácica descendente / Ischemic preconditioning and spinal cord function monitoring in the descending thoracic aorta approach

OBJETIVOS: Avaliar a eficácia do pré-condicionamento isquêmico (PI) agudo, guiado por potenciais evocados somatossensoriais (PESS), como método de proteção medular em cães e analisar o valor dos PESS na monitorização da função medular. MÉTODOS: Foram utilizados 28 cães submetidos à isquemia medular obtida pelo pinçamento da aorta torácica descendente. No grupo C45, o tempo de oclusão aórtica foi de 45 min (n = 7); no grupo PI45, os cães foram submetidos ao PI antes do pinçamento aórtico por 45 min (n = 7). No grupo C60, os cães foram submetidos a 60 min de oclusão aórtica (n = 7) e no grupo PI60, os cães foram submetidos ao PI, seguido pelo pinçamento aórtico por 60 min. Os ciclos de PI foram determinados pelas alterações dos PESS. RESULTADOS: Os índices de Tarlov dos grupos pré-condicionados foram significativamente melhores que os dos grupos de controle (p = 0,005). Observou-se paraplegia em três cães do C45 e em seis do C60, enquanto todos os cães do PI45 permaneceram neurologicamente normais, assim como quatro do grupo PI60. Houve correlação entre o tempo de recuperação dos PESS após a reperfusão aórtica e o estado neurológico pós-operatório (p = 0,011), com sensibilidade e especificidade de 0,75 e 0,83, respectivamente. CONCLUSÃO: O PI agudo repetitivo, baseado na monitorização do PESS, induziu proteção à isquemia medular causada pelo pinçamento aórtico prolongado. A monitorização do PESS parece ser um bom método de detecção precoce do comprometimento isquêmico medular.

OBJECTIVES: To evaluate the effectiveness of acute ischemic preconditioning (IP), based on somatosensory evoked potentials (SSEP) monitoring, as a method of spinal cord protection and to asses SSEP importance in spinal cord neuromonitoring. METHODS: Twenty-eight dogs were submitted to spinal cord ischemic injury attained by descending thoracic aorta cross-clamping. In the C45 group, the aortic cross-clamping time was 45 min (n=7); in the IP45 group, the dogs were submitted to IP before the aortic cross-clamping for 45 min (n=7). In the C60 group, the dogs were submitted to 60 min of aortic cross-clamping (n=7), as in the IP60 group that was previously submitted to IP. The IP cycles were determined based on SSEP changes. RESULTS: Tarlov scores of the IP groups were significantly better than those of the controls (p = 0.005). Paraplegia was observed in 3 dogs from C45 and in 6 from C60 group, although all dogs from IP45 group were neurologically normal, as 4 dogs from IP60. There was a significant correlation between SSEP recovery time until one hour of aortic reperfusion and the neurological status (p = 0.011), showing sensitivity of 75 percent and specificity of 83 percent. CONCLUSION: Repetitive acute IP based on SSEP is a protection factor during spinal cord ischemia, decreasing paraplegia incidence. SSEP monitoring seems to be a good neurological injury assessment method during surgical procedures that involve spinal cord ischemia.

Estudo comparativo entre o pré-condicionamento isquêmico e a drenagem liquórica como métodos de proteção medular em cães / Comparative study between ischemic preconditioning and cerebrospinal fluid drainage as methods of spinal cord protection in dogs

OBJETIVO: Este estudo compara os efeitos do pré-condicionamento isquêmico imediato, baseado na monitorização do potencial evocado somatossensitivo (PESS), com aqueles da drenagem do líquido cefalorraquidiano, em um modelo de oclusão da aorta torácica descendente em cães. MÉTODO: Dezoito cães foram submetidos à isquemia medular induzida pela oclusão da aorta torácica descendente por 60 minutos. O Grupo Controle foi submetido à oclusão da aorta (n=6), o Grupo Pré-Condicionamento Isquêmico (PCI), ao pré-condicionamento isquêmico (n=6) e o grupo drenagem, à drenagem do líquido cefalorraquidiano (n=6), imediatamente antes da oclusão da aorta. A condição neurológica foi acessada por um observador independente, de acordo com a escala de Tarlov. Os animais foram sacrificados e as medulas retiradas para exame histopatológico. RESULTADOS: Pressões da aorta proximal e distal à oclusão foram semelhantes nos três grupos. Sete dias após o procedimento, o índice de Tarlov foi significativamente maior em comparação ao Grupo Controle, somente no Grupo PCI (p<0,05). Foram observados valores menores no tempo de recuperação do PESS com o uso da drenagem liquórica durante a fase final de reperfusão (p<0,01). Exame histopatológico evidenciou necrose menos grave na substância cinzenta torácica e lombar, nos animais submetidos aos dois métodos de proteção medular, sendo mais pronunciada no Grupo PCI (p<0,001). CONCLUSÃO: A drenagem do líquor e o pré-condicionamento isquêmico parecem proteger a medula espinhal, durante a oclusão da aorta torácica descendente. Entretanto, o nível de proteção medular obtido parece ser mais significativo com a drenagem do líquido cefalorraquidiano.

OBJECTIVE: This study compares the effects of immediate ischemic preconditioning based on somatosensory evoked potential (SSEP) monitoring with those of cerebrospinal fluid drainage in a model of descending thoracic aorta occlusion in dogs. METHOD: Eighteen dogs were submitted to spinal cord ischemia induced by descending thoracic aortic cross-clamping for 60 minutes. The Control Group underwent only aortic cross-clamping (n=6). The Ischemic Preconditioning Group (IPC) underwent ischemic preconditioning (n=6) and the Drainage Group underwent cerebrospinal fluid drainage (n=6), immediately before aortic cross-clamping. An independent observer assessed neurological status according to the Tarlov score. The animals were sacrificed and spinal cord harvested for histopathologic study. RESULTS: Aortic pressure before and after the occluded segment was similar in the three groups. Seven days after the procedure, Tarlov scores were significantly higher only in the Drainage Group when compared to the Control Group (p<0.05). Lower SSEP recovery times were also observed with cerebrospinal fluid drainage during the final reperfusion period (p<0.01). In the histopathologic study, stain showed less significant neuronal necrosis in the thoracic and lumbar gray matter in animals submitted to both methods of spinal cord protection, with it being more pronounced in the Ischemic Preconditioning Group (p<0.001). CONCLUSION: Cerebrospinal fluid drainage and immediate ischemic preconditioning seems to protect the spinal cord during descending thoracic aorta cross-clamping. Nevertheless, the obtained level of spinal cord protection seems to be more significant with cerebrospinal fluid drainage.