Microblock for occlusion of small vessels

1976 ◽  
Vol 44 (6) ◽  
pp. 757-758 ◽  
Author(s):  
Sanford J. Wright
Keyword(s):  
Content Type ◽  
Small Vessels ◽  
Fine Print

✓ A small microvascular occluder termed a “microblock” is described. It has the advantages of controlled gentle occlusion and small size.

Microvascular patch technique with and without Silastic T-tube bypass

1984 ◽  
Vol 60 (2) ◽  
pp. 287-295 ◽  
Author(s):  
Peter C. Haines ◽  
R. M. Peardon Donaghy
Keyword(s):  
Foreign Body ◽  
Suture Material ◽  
Vascular Occlusion ◽  
Current Data ◽  
Content Type ◽  
Small Vessels ◽  
T Tube ◽  
Patch Closure ◽  
Patch Technique ◽  
Fine Print

✓ Poor patency results in the surgery of small vessels operated on between 1959 to 1964 was demonstrated to be in part due to the long period of occlusion of the operated vessel during surgery and the presence of a foreign body (suture) in the lumen of the vessel postoperatively. New suture techniques and T-tube bypass were introduced at that time. New experimental data have not been extensively sought since that time. To provide further current data regarding the above observations, 110 arterial vessels (60 carotid arteries 1.1 to 1.3 mm in outside diameter (OD) and 50 femoral arteries 0.6 to 0.7 mm OD) were operated on in rats to compare the bypass versus non-bypass and vein patch closure techniques. In 1-mm vessels, patency rates 1 month after surgery were 100% regardless of the use of bypass or type of closure. Improved visualization, better suture material, and improved surgical skill were probably chiefly responsible for this success. The success rate was not as encouraging, however, in vessels of 0.6 mm OD. The following points are brought out: 1) The presence of the bypass causes damage to the intima in 0.6 mm OD vessels and should not be used. Smaller bypasses do not conduct blood well. 2) Bypass is not required in 1-mm vessels as the patency rate is satisfactory and not altered by its use. 3) The major indication for T-tube bypass is in vessels of 1 mm OD and larger, that nourish tissue which would be damaged by vascular occlusion for 20 to 40 minutes. 4) Foreign body (suture) in the lumen is poorly tolerated in 0.6 mm vessels, but can be tolerated more easily in larger vessels. 5) Techniques that limit the amount of suture material in the lumen are indicated in 0.6-mm vessels. 6) After 1 month, suture material has an epithelial covering and if patency has been maintained for that period of time it is likely to remain.

Impaired microvascular filling after focal cerebral ischemia in monkeys

1972 ◽  
Vol 36 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Robert M. Crowell ◽  
Yngve Olsson
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Cerebrovascular Diseases ◽  
Subcortical Structures ◽  
Content Type ◽  
Microsurgical Technique ◽  
Small Vessels ◽  
Mca Occlusion ◽  
Vascular Channels ◽  
Fine Print

✓ Impairment of microvascular filling was demonstrated in relation to focal cerebral ischemia in the monkey. Temporary or sustained middle cerebral artery (MCA) clipping was achieved with a microsurgical technique. Animals were sacrificed by perfusion with a carbon black suspension. Brains were fixed in formalin, and the extent of microvascular carbon filling was estimated grossly and microscopically. In most animals, MCA occlusion of 2 hours to 7 days produced diminished filling in small vessels in the MCA territory of supply. The impairment of filling was most pronounced in the deep subcortical structures but also affected the cortex in some animals. Temporary and sustained occlusion of equal duration produced roughly equivalent areas of abnormal filling. The impairment of vascular filling tended to be more extensive with increasing duration of occlusion. Hypotension during MCA occlusion caused almost total non-filling of the microvasculature in the entire MCA territory. Impaired filling of vascular channels may play a role in the pathogenesis of some clinical cerebrovascular diseases.

Immunocytochemical evidence of lymphocytic derivation of neoplastic cells in malignant angioendotheliomatosis

1991 ◽  
Vol 74 (5) ◽  
pp. 757-762 ◽  
Author(s):  
W. Craig Clark ◽  
F. Curtis Dohan ◽  
Timothy Moss ◽  
John B. Schweitzer
Keyword(s):  
Endothelial Cell Proliferation ◽  
Cell Of Origin ◽  
Content Type ◽  
Therapeutic Implications ◽  
Ulex Europaeus ◽  
Small Vessels ◽  
Immunohistochemical Techniques ◽  
Brain And Spinal Cord ◽  
The Brain ◽  
Fine Print

✓ Neoplastic angioendotheliomatosis is a rare disorder usually characterized by primarily cutaneous or neurological symptoms. Approximately 40 cases of malignant angioendotheliomatosis with primary central nervous system (CNS) symptoms have been reported. Some investigators have postulated a hematopoietic origin for this neoplasm. Most of the literature, however, has perpetuated the idea that the often bizarre symptoms seen with this entity result from neoplastic endothelial cell proliferation within the small vessels of affected organs, including the brain and spinal cord. This report describes the immunohistochemical examination and confirmation of the cell of origin of this neoplasm based on five previously unpublished cases of malignant angioendotheliomatosis with primarily CNS symptoms. It includes the first documentation of a T-cell lymphoma presenting as malignant angioendotheliomatosis. All cases include autopsy findings, and in four cases the diagnosis was made postmortem. One case was proven by stereotactic biopsy, but the patient succumbed as a result of severe intracranial bleeding that occurred at the time of biopsy. Tissues were studied with avidin-biotin peroxidase immunohistochemical techniques using a panel of monoclonal antibodies directed against the leukocyte common antigen, LN-1, LN-2, and anti-Factor VIII, and also using Ulex europaeus agglutinin 1. Based on the results obtained, the authors conclude that the proliferative cells seen within the vessel lumina are of lymphocytic origin and agree that the condition should more properly be designated intravascular lymphomatosis. The therapeutic implications of this conclusion point to the possible administration of chemotherapy and radiotherapy in an effort to achieve remissions in an otherwise relentlessly progressive neurological disorder.

Cyst formation following gamma knife surgery for intracranial meningioma

2005 ◽  
Vol 102 ◽  
pp. 134-139 ◽  
Author(s):  
Takashi Shuto ◽  
Shigeo Inomori ◽  
Hideyo Fujino ◽  
Hisato Nagano ◽  
Naoki Hasegawa ◽  
...  
Keyword(s):  
Gamma Knife ◽  
De Novo ◽  
Cyst Formation ◽  
Tumor Location ◽  
Gamma Knife Surgery ◽  
Intracranial Meningioma ◽  
Content Type ◽  
Small Vessels ◽  
The Mean ◽  
Fine Print

Object.The authors conducted a study to evaluate the clinical significance of cyst formation or enlargement after gamma knife surgery (GKS) for intracranial benign meningiomas.Methods.The medical records of 160 patients with 184 tumors were examined for those with follow-up data of more than 2 years among 270 patients who underwent GKS for intracranial meningiomas between February 1992 and November 2001.Cyst formation or enlargement following GKS was observed in five patients, one man and four women (mean age 61.2 years). The tumor location was the sphenoid ridge in one case, petroclival in two, tentorium in one, and parasagittal region in one. All patients underwent surgery before GKS. The mean tumor volume was 10.5 cm3, the mean margin dose was 13.4 Gy (median 14 Gy), and the mean maximum dose was 27.5 Gy (median 24.1 Gy). At the time of GKS three tumors were associated with cyst, of which two enlarged after radiosurgery. Three cysts developed de novo after GKS. Three of the five patients needed surgery to treat the cyst formation or enlargement. Histological examination demonstrated various findings such as tumor necrosis, proliferation of small vessels, vascular obliteration, and hemosiderin deposits.Conclusions.New cyst formation following GKS for benign intracranial meningioma is relatively rare; however, both preexisting and newly developed cysts tend to enlarge after GKS and often require surgery.

End-to-side anastomosis of small vessels using an Nd:YAG laser with a hemispherical contact probe

1992 ◽  
Vol 76 (3) ◽  
pp. 546-549 ◽  
Author(s):  
Cornelis A. F. Tulleken ◽  
Andries van Dieren ◽  
Ruud M. Verdaasdonk ◽  
Wim Berendsen
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Nd:Yag Laser ◽  
Superficial Temporal Artery ◽  
Temporal Artery ◽  
Content Type ◽  
Small Vessels ◽  
Contact Probe ◽  
A New Technique ◽  
Fine Print

✓ A new technique is described which enables the surgeon to perform an end-to-side anastomosis between arteries with little (< 2 minutes) or no occlusion of the recipient artery. The technique was developed in rabbits, but has recently been successfully used in a patient in whom an anastomosis between the superficial temporal artery and a proximal branch of the middle cerebral artery was created.

Transparent optical neurosurgical instruments

1984 ◽  
Vol 60 (1) ◽  
pp. 208-210 ◽  
Author(s):  
Walter J. Levy
Keyword(s):  
Optical Properties ◽  
Blood Vessels ◽  
Surgical Procedures ◽  
High Strength ◽  
Operating Microscope ◽  
Content Type ◽  
Small Vessels ◽  
Surgical Field ◽  
Fine Print

✓ Neurosurgical instrumentation over the last two decades has improved with the increasing use of the operating microscope and has provided much better visualization and lighting of the surgical field. During this time, dissecting instruments have become smaller, but they sacrifice some of the microscopic gains because they are made of opaque metal. This has the disadvantage of hiding from the surgeon the area of the surgical field being worked on. This paper reports the development of transparent instruments that are strong enough to be used in dissection and yet do not sacrifice part of the improved visualization and lighting gained with the operating microscope. Made of a high-strength plastic, these instruments can be used for dissection in surgical procedures and allow the surgeon to look through them and observe the tissues underneath. He can watch the condition of blood vessels and nervous tissues with an improved visibility that can help to avoid damage to delicate structures. Furthermore, as hidden structures such as small vessels come into view they are identified earlier. These instruments can also incorporate jeweled cutting edges and use their optical properties to improve further visualization of the surgical field.

Cyst formation following gamma knife surgery for intracranial meningioma

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 134-139 ◽  
Author(s):  
Takashi Shuto ◽  
Shigeo Inomori ◽  
Hideyo Fujino ◽  
Hisato Nagano ◽  
Naoki Hasegawa ◽  
...  
Keyword(s):  
Gamma Knife ◽  
De Novo ◽  
Cyst Formation ◽  
Tumor Location ◽  
Gamma Knife Surgery ◽  
Intracranial Meningioma ◽  
Content Type ◽  
Small Vessels ◽  
The Mean ◽  
Fine Print

Object. The authors conducted a study to evaluate the clinical significance of cyst formation or enlargement after gamma knife surgery (GKS) for intracranial benign meningiomas. Methods. The medical records of 160 patients with 184 tumors were examined for those with follow-up data of more than 2 years among 270 patients who underwent GKS for intracranial meningiomas between February 1992 and November 2001. Cyst formation or enlargement following GKS was observed in five patients, one man and four women (mean age 61.2 years). The tumor location was the sphenoid ridge in one case, petroclival in two, tentorium in one, and parasagittal region in one. All patients underwent surgery before GKS. The mean tumor volume was 10.5 cm3, the mean margin dose was 13.4 Gy (median 14 Gy), and the mean maximum dose was 27.5 Gy (median 24.1 Gy). At the time of GKS three tumors were associated with cyst, of which two enlarged after radiosurgery. Three cysts developed de novo after GKS. Three of the five patients needed surgery to treat the cyst formation or enlargement. Histological examination demonstrated various findings such as tumor necrosis, proliferation of small vessels, vascular obliteration, and hemosiderin deposits. Conclusions. New cyst formation following GKS for benign intracranial meningioma is relatively rare; however, both preexisting and newly developed cysts tend to enlarge after GKS and often require surgery.

Magnesium and experimental vasospasm

2004 ◽  
Vol 100 (1) ◽  
pp. 106-110 ◽  
Author(s):  
R. Loch Macdonald ◽  
Daniel J. Curry ◽  
Yasuo Aihara ◽  
Zhen-Du Zhang ◽  
Babak S. Jahromi ◽  
...  
Keyword(s):  
Magnesium Sulfate ◽  
Cerebral Vasospasm ◽  
Standard Dose ◽  
Cerebral Arteries ◽  
Elevated Serum ◽  
Treated Group ◽  
Dose Finding ◽  
Content Type ◽  
Small Vessels ◽  
Fine Print

Object. Interest has developed in the use of magnesium (Mg++) as a neuroprotectant and antivasospastic agent. Magnesium may increase cerebral blood flow (CBF) and reduce the contraction of cerebral arteries caused by various stimuli. In this study the authors tested the hypothesis that a continuous intravenous infusion of Mg++ reduces cerebral vasospasm after experimental subarachnoid hemorrhage (SAH). Methods. A dose-finding study was conducted in five monkeys (Macaca fascicularis) to determine what doses of intravenous MgSO4 elevate the cerebrospinal fluid (CSF) concentrations of Mg++ to vasoactive levels and to determine what effects these doses have on the diameters of cerebral arteries, as shown angiographically. After a standard dose of MgSO4 had been selected it was then administered in a randomized, controlled, blinded study to 10 monkeys (five animals/group) with SAH, beginning on Day 0 and continuing for 7 days, at which time angiography was repeated. A 0.086-g/kg bolus of MgSO4 followed by an infusion of 0.028 g/kg/day MgSO4 significantly elevated serum and CSF levels of Mg++ (five monkeys). Magnesium sulfate significantly elevated the serum level of total Mg++ from a control value of 0.83 ± 0.04 mmol/L to 2.42 ± 1.01 mmol/L on Day 7 and raised the CSF level from 1.3 ± 0.04 mmol/L to 1.76 ± 0.14 mmol/L. There was no angiographic evidence of any effect of MgSO4 on normal cerebral arteries. After SAH, the vasospasm in the middle cerebral artery was not significantly reduced (46 ± 8% in the MgSO4-treated group compared with 35 ± 6% in the placebo [vehicle]-treated group, p > 0.05, unpaired t-test). Conclusions. Magnesium sulfate did not significantly reduce cerebral vasospasm after SAH in the doses tested. An investigation of SAH is warranted mainly to test whether a benefit can be achieved by neuroprotection or by augmentation of CBF by dilation of small vessels and/or collateral pathways.

Evaluation of gamma thalamotomy for parkinsonian and other tremors: survival of neurons adjacent to the thalamic lesion after gamma thalamotomy

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 120-127 ◽  
Author(s):  
Chihiro Ohye ◽  
Tohru Shibazaki ◽  
Junji Ishihara ◽  
Jie Zhang
Keyword(s):  
Tissue Reaction ◽  
Vascular Lesions ◽  
Thalamic Lesion ◽  
Mr Images ◽  
Unsatisfactory Result ◽  
Content Type ◽  
Rhythmic Discharge ◽  
Latent Interval ◽  
Fine Print

Object. The effects of gamma thalamotomy for parkinsonian and other kinds of tremor were evaluated. Methods. Thirty-six thalamotomies were performed in 31 patients by using a 4-mm collimator. The maximum dose was 150 Gy in the initial six cases, which was reduced to 130 Gy thereafter. The longest follow-up period was 6 years. The target was determined on T2-weighted and proton magnetic resonance (MR) images. The point chosen was in the lateral-most part of the thalamic ventralis intermedius nucleus. This is in keeping with open thalamotomy as practiced at the authors' institution. In 15 cases, gamma thalamotomy was the first surgical procedure. In other cases, previous therapeutic or vascular lesions were visible to facilitate targeting. Two types of tissue reaction were onserved on MR imaging: a simple oval shape and a complex irregular shape. Neither of these changes affected the clinical course. In the majority of cases, the tremor subsided after a latent interval of approximately 1 year after irradiation. The earliest response was demonstrated at 3 months. In five cases the tremor remained. In four of these cases, a second radiation session was administered. One of these four patients as well as another patient with an unsatisfactory result underwent open thalamotomy with microrecording. In both cases, depth recording adjacent to the necrotic area revealed normal neuronal activity, including the rhythmic discharge of tremor. Minor coagulation was performed and resulted in immediate and complete arrest of the remaining tremor. Conclusions. Gamma thalamotomy for Parkinson's disease seems to be an alternative useful method in selected cases.

Gamma knife radiosurgery as a single treatment modality for large cerebral arteriovenous malformations

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 113-119 ◽  
Author(s):  
D. Hung-Chi Pan ◽  
Wan-Yuo Guo ◽  
Wen-Yuh Chung ◽  
Cheng-Ying Shiau ◽  
Yue-Cune Chang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Radiation Treatment ◽  
Gamma Knife Radiosurgery ◽  
Consecutive Series ◽  
Content Type ◽  
Obliteration Rate ◽  
Complete Obliteration ◽  
Fine Print

Object. A consecutive series of 240 patients with arteriovenous malformations (AVMs) treated by gamma knife radiosurgery (GKS) between March 1993 and March 1999 was evaluated to assess the efficacy and safety of radiosurgery for cerebral AVMs larger than 10 cm3 in volume. Methods. Seventy-six patients (32%) had AVM nidus volumes of more than 10 cm3. During radiosurgery, targeting and delineation of AVM nidi were based on integrated stereotactic magnetic resonance (MR) imaging and x-ray angiography. The radiation treatment was performed using multiple small isocenters to improve conformity of the treatment volume. The mean dose inside the nidus was kept between 20 Gy and 24 Gy. The margin dose ranged between 15 to 18 Gy placed at the 55 to 60% isodose centers. Follow up ranged from 12 to 73 months. There was complete obliteration in 24 patients with an AVM volume of more than 10 cm3 and in 91 patients with an AVM volume of less than 10 cm3. The latency for complete obliteration in larger-volume AVMs was significantly longer. In Kaplan—Meier analysis, the complete obliteration rate in 40 months was 77% in AVMs with volumes between 10 to 15 cm3, as compared with 25% for AVMs with a volume of more than 15 cm3. In the latter, the obliteration rate had increased to 58% at 50 months. The follow-up MR images revealed that large-volume AVMs had higher incidences of postradiosurgical edema, petechiae, and hemorrhage. The bleeding rate before cure was 9.2% (seven of 76) for AVMs with a volume exceeding 10 cm3, and 1.8% (three of 164) for AVMs with a volume less than 10 cm3. Although focal edema was more frequently found in large AVMs, most of the cases were reversible. Permanent neurological complications were found in 3.9% (three of 76) of the patients with an AVM volume of more than 10 cm3, 3.8% (three of 80) of those with AVM volume of 3 to 10 cm3, and 2.4% (two of 84) of those with an AVM volume less than 3 cm3. These differences in complications rate were not significant. Conclusions. Recent improvement of radiosurgery in conjunction with stereotactic MR targeting and multiplanar dose planning has permitted the treatment of larger AVMs. It is suggested that gamma knife radiosurgery is effective for treating AVMs as large as 30 cm3 in volume with an acceptable risk.

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