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Juha Hernesniemi

Publications and source records attributed to Juha Hernesniemi.

At least 19 recordsLinked to original sources
PubMed2007

Microneurosurgical management of proximal middle cerebral artery aneurysms.

BACKGROUND: The M1As are located in the main trunk (M1) of the MCA, between the bifurcation of the ICA and the main bifurcation of M1. Proximal MCA aneurysms are often small and thin-walled, which makes their proper clipping tedious. There are few reports on their microsurgery. METHODS: This review, and the whole series on intracranial aneurysms, is mainly based on the personal microneurosurgical experience of the senior author (JH) in 2 Finnish centers (Helsinki and Kuopio), which serve, without selection, the catchment area in the southern and eastern Finland. RESULTS: These 2 centers have treated more than 10000 patients with aneurysm since 1953. We review the practical anatomy, preoperative planning, and avoidance of complications in the microsurgical dissection and clipping of M1As which form 7.4% of all intracranial and 14% of all MCA aneurysms in our patients. CONCLUSIONS: Proximal MCA aneurysms are often wide-necked and intimately connected to an M1 branch at its origin on M1, features that favor exosurgery rather than endosurgery. The direction and course of the parent and branching arteries and the orientation of the fundus are the most important factors affecting the efficacy and safety of clipping.

Humans↗
PubMed2006

Water dissection technique of Toth for opening neurosurgical cleavage planes.

BACKGROUND: The low-pressure water dissection technique of Toth, first reported in 1987, is a method to cautiously open neurosurgical cleavage planes such as the sylvian fissure or the interhemispheric space, and the interfaces between extraparenchymal masses and the adjacent brain. The aim of this technical report is to present our long-term experience with this simple and elegant asset of microneurosurgery and to promote its widespread use. METHOD: Water is injected under microscopic control by a hand-held syringe with a blunt needle or by an irrigating balloon applying repeated injections of physiological saline into the cleavage plane to open it. FINDINGS AND CONCLUSION: The water dissection technique of Toth has been extensively used in Budapest and Helsinki in thousands of microsurgical cases, in removal of meningiomas and to open sylvian and interhemispheric fissure. In our experience, there have been no noticeable complications, and we recommend this technique for widespread use. It is a very inexpensive, simple, and effective method not requiring any expensive or complicated devices.

Dissection↗
PubMed2006

Principles of neuroanesthesia in aneurysmal subarachnoid hemorrhage: The Helsinki experience.

BACKGROUND: Aneurysmal subarachnoid hemorrhage is a devastating disease that is followed by a marked stress response affecting other organs besides the brain. The aim in the management of patients with aSAH is not only to prevent rebleedings by treating the aneurysm by either microneurosurgery or endovascular surgery, but also to evacuate acute space-occupying hematomas and to treat hydrocephalus. METHODS: This review is based on the experience of the authors in the management of more than 7500 patients with aSAH treated in the Department of Neurosurgery at Helsinki University Central Hospital, Finland. RESULTS: The role of the neuroanesthesiologist together with the neurosurgeon may begin in the emergency department to assess and stabilize the general medical and neurologic status of the patients. Early preoperative management of patients in the NICU, prevention of rebleeding, and providing a slack brain during microneurosurgical procedures are further steps. Postoperative management, prevention, and treatment of possible medical complications and cerebrovascular spasm are as necessary as high-quality microsurgery. CONCLUSION: Multidisciplinary and professional teamwork is essential in the management of patients with cerebral aneurysms.

Anesthesia↗
PubMed2006

Growth factor receptor expression and remodeling of saccular cerebral artery aneurysm walls: implications for biological therapy preventing rupture.

OBJECTIVE: Remodeling of the saccular cerebral artery aneurysm (SCAA) wall, known to be associated with rupture, might be modified with bioactive endovascular implants or systemic drug therapy targeted at growth factor receptors to prevent rupture. The receptors regulating SCAA wall remodeling are, however, unknown. MATERIALS AND METHODS: Immunostaining for 12 growth factor receptors, and markers for matrix synthesis, proliferation, and inflammatory cell infiltration, were analyzed in 21 unruptured and 35 ruptured aneurysm fundi resected after microsurgical clipping of the aneurysm neck. The results were compared with clinical and radiological data. RESULTS: Eleven of the 12 receptors studied were expressed at varying intensities in the 56 SCAA walls. Only transforming growth factor (TGF)beta-R2 and vascular endothelial growth factor (VEGF)-R1 were associated with rupture and basic fibroblast growth factor-R1 with minor leaks (P = 0.018). TGFbeta-R3 and VEGF-R1 was associated with wall remodeling (P = 0.043 and 0.027), and VEGF-R1 was associated with T-cell and macrophage infiltration as well as organization of luminal thrombosis (P = 0.019). VEGF-R2 was associated with myointimal hyperplasia (P = 0.017) and proliferation (P < 0.001). CONCLUSION: VEGF, TGFbeta, and basic fibroblast growth factor receptors were associated with SCAA wall remodeling, making them potential targets for bioactive endovascular implants or drug therapy aiming to reinforce the SCAA wall.

Adolescent↗
PubMed2006

Contribution of mural and bone marrow-derived neointimal cells to thrombus organization and wall remodeling in a microsurgical murine saccular aneurysm model.

OBJECTIVE: Endovascular occlusive therapy of human saccular cerebral artery aneurysms may fail because of thrombus recanalization and incomplete neointima formation. Bone marrow-derived progenitor cells may contribute to these processes, but their role in human saccular cerebral artery aneurysms and experimental aneurysm models remains unclear. METHODS: Experimental saccular aneurysms were constructed from syngeneic thoracic aortas transplanted end-to-side to the abdominal aorta of Wistar rats (n = 14), C57/B6 mice (n = 13), ApoE mice (n = 7), reporter gene expressing ROSA mice (n = 7), and mice with labeled bone marrow (ROSA [n = 12] or green fluorescent protein [n = 3]). Magnetic resonance imaging or angiography was used to monitor patency of the experimental aneurysms. Histology and immunohistochemistry were used to study thrombus organization and neointima formation and X-gal staining and confocal microscopy to study the origin of neointimal cells. RESULTS: Experimental aneurysms developed luminal pads of neointimal hyperplasia or organizing thrombosis that became thicker and occluded partly the lumen at later time points during the first week. Reporter gene mice (ROSA) revealed that 42 to 81% (median, 58%) of neointimal hyperplasia/organizing thrombosis was derived from the experimental aneurysm wall. Bone marrow-derived neointimal cells were found in only 5 of 15 mice (range, 11-73 per section; a median of 22 cells among a total of 2000-6000 wall cells). CONCLUSION: Thrombus organizing or neointimal cells were mostly derived from the experimental aneurysm wall, with only a minor contribution from the bone marrow. In human saccular cerebral artery aneurysms, the contribution of bone marrow-derived neointimal cells might be more important and should be compared with that found in other experimental models used to develop endovascular therapies.

Animals↗
PubMed2006

Complement activation associates with saccular cerebral artery aneurysm wall degeneration and rupture.

OBJECTIVE: Saccular cerebral artery aneurysm (SCAA) wall degeneration and inflammatory cell infiltrations associate with aneurysm rupture and subarachnoid hemorrhage, resulting in a devastating form of stroke. The complement system is the key mediator of inflammation and household processing of injured tissue. We studied how complement activation associates with SCAA wall degeneration and rupture to better understand the pathobiology of SCAA wall rupture. METHODS: Unruptured (n = 26) and ruptured (n = 32) SCAA fundi resected after microsurgical clipping were studied by immunostaining for complement activation (membrane attack complex [MAC]) and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling reaction for related cell death. Complement activation was correlated with clinical and other histological parameters. Electromicroscopy and immunoelectron microscopy were used for locating MAC depositions at the ultrastructural level. RESULTS: MAC localized consistently in a decellularized layer in the outer SCAA wall, and was found in all SCAA samples. The percentage of MAC-positive area relative to the total SCAA wall surface area (range, 5-77%) was greater in ruptured (n = 25; median, 39%) than in unruptured SCAAs (n = 18; median, 20%; P = 0.005). It also associated significantly with SCAA wall degeneration (P < 0.001), de-endothelialization(P < 0.001), and CD163+ macrophage (P = 0.023) and T-lymphocyte (P = 0.030) infiltrations. Apoptotic terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling-positive nuclei and MAC were located at the same wall areas in four out of 14 double-stained samples, but no double-positive cells were found. Electromicroscopy and immunoelectron microscopy of an unruptured SCAA showed cell death in the MAC-positive layers in the outer SCAA wall. CONCLUSION: These data suggests that complement activation and MAC formation are involved in SCAA wall degeneration and rupture.

Adolescent↗
PubMed2006

Principles of microneurosurgery for safe and fast surgery.

Since their introduction by Prof. Yaşargil in the 1960s, Microneurosurgical techniques have been the essentials of neurosurgical practice. Principles of Microneurosurgery are mainly based upon handling the lesions of different characteristics that can be localized in any part of the nervous system. Whereas the aim is to treat these lesions with efficacy and precision, the performance should be non-traumatic and minimally invasive. Delicate movements of instruments under the magnification of an operating microscope require a good knowledge of Microneurosurgical anatomy and experience. Professional teamwork is the essential part of Microneurosurgical operations. Fascinating approaches are not practical unless combined with appropriate positioning and optimal conduction of Neuroanesthesia. Although the neurosurgical operations are highly dependent on technological advancements, their use should be adjusted according to personal preferences and financial resources. To keep the operations simple and fast, and appreciate normal anatomy, only a limited array of instruments is preferable for use. The basic principles of Microneurosurgery discussed in this chapter are based on the Helsinki and Kuopio Neurosurgery practices in Finland, as well as the Senior Author's (J.H.) experience in approximately 10,000 microsurgery operations. The question to be addressed is: How does one perform operations safer and faster while preserving the normal anatomy?

Humans↗
PubMed2005

Some collected principles of microneurosurgery: simple and fast, while preserving normal anatomy: a review.

Microneurosurgical techniques introduced by Prof Yasargil in the 1960s have increased the neurosurgeon's ability to operate in small and often very narrow and deep gaps. Microneurosurgical techniques-ensuring an almost bloodless field and mostly obviating need for transfusion-should be atraumatic and noninvasive to the already lesioned central nervous system tissues and structures. Instruments in microneurosurgery range from very short to very long and from sturdy to delicate, depending on the working depth, characteristics of tissues, and the microneurosurgical anatomy. However, to keep it simple and fast, and to appreciate normal anatomy, it is preferable to use only a limited array of instruments. Besides the use of instruments and the operating microscope, everything else in the neurosurgical arena should be optimized and professional, such as the positioning of the patient and the conduct of neuroanesthesia. This review of the very basics is distilled from the Helsinki and Kuopio neurosurgery practices in Finland and from the senior author's (JH) experience of close to 10,000 operations, and this is to encourage young neurosurgeons of the world-most of them working with limited resources-to continue to improve their microneurosurgical skills to serve their patients best.

Brain Diseases↗
PubMed2005

Surgical technique to retract the tentorial edge during subtemporal approach: technical note.

OBJECTIVE: To describe a surgical technique to retract the tentorial edge during the subtemporal approach initially introduced and used widely by Drake and Peerless to treat distal basilar artery aneurysms. METHODS: One of the most important parts of the exposure is to reflect the edge of the tentorium downward by 1 cm or more and to tether it with a suture placed lateral to or behind the insertion of the trochlear nerve and then to the dura mater of the floor of the middle fossa. Surgical forceps or a sharp dural hook are used to elevate the tentorial edge, in front of the trochlear nerve. A small incision is made on the surface of the floor of the middle fossa using a sharp bipolar forceps, and a small straight microclip is inserted with one arm through the incision on the surface of the floor of the middle fossa and the other at the free margin of the tentorial edge. RESULTS: The method described has been used by the senior author in more than 100 operations as a simple and fast means of tethering the free margin of the tentorial edge simply and quickly. CONCLUSION: We inserted a small straight microclip with one arm through the incision on the surface of the floor of the middle fossa and the other at the free margin of the tentorial edge as a fast and simple method of retracting the tentorial edge during a subtemporal approach.

Basilar Artery↗
PubMed2004

Remodeling of saccular cerebral artery aneurysm wall is associated with rupture: histological analysis of 24 unruptured and 42 ruptured cases.

BACKGROUND AND PURPOSE: The cellular mechanisms of degeneration and repair preceding rupture of the saccular cerebral artery aneurysm wall need to be elucidated for rational design of growth factor or drug-releasing endovascular devices. METHODS: Patient records, preoperative vascular imaging studies, and the snap-frozen fundi resected after microsurgical clipping from 66 aneurysms were studied. Immunostainings for markers of smooth muscle cell (SMC) phenotype, proliferation, and inflammatory cell subtypes and TUNEL reaction were performed. RESULTS: Unruptured (24) and ruptured (42) aneurysms had similar dimensions (median diameter in unruptured 6 mm; median in ruptured 7 mm; P=0.308). We identified 4 basic types of aneurysm wall that associated with rupture: (1) endothelialized wall with linearly organized SMCs (17/66; 42% ruptured), (2) thickened wall with disorganized SMCs (20/66; 55% ruptured), (3) hypocellular wall with either myointimal hyperplasia or organizing luminal thrombosis (14/66; 64% ruptured), and (4) an extremely thin thrombosis-lined hypocellular wall (15/66; 100% ruptured). Apoptosis, de-endothelialization, luminal thrombosis, SMC proliferation, and T-cell and macrophage infiltration associated with rupture. Furthermore, macrophage infiltration associated with SMC proliferation, and both were increased in ruptured aneurysms resected <12 hours from rupture, suggesting that these were not just reactive changes. CONCLUSIONS: Before rupture, the wall of saccular cerebral artery aneurysm undergoes morphological changes associated with remodeling of the aneurysm wall. Some of these changes, like SMC proliferation and macrophage infiltration, likely reflect ongoing repair attempts that could be enhanced with pharmacological therapy.

Aneurysm, Ruptured↗
PubMed2004

Intracranial aneurysms in Finnish families: confirmation of linkage and refinement of the interval to chromosome 19q13.3.

We recently reported a two-stage genomewide screen of 48 sib pairs affected with intracranial aneurysms (IAs) that revealed suggestive linkage to chromosome 19q13, with a LOD score of 2.58. The region supporting linkage spanned approximately 22 cM. Here, we report a follow-up study of the locus at 19q13, with a sample size expanded to 139 affected sib pairs, along with 83 other affected relative pairs (222 affected relative pairs in total). Suggestive linkage was observed in both independent sample sets, and linkage was significant in the combined set at 70 cM (LOD score 3.50; P=.00006) and at 80 cM (LOD score 3.93; P=.00002). Linkage was highly significant at 70 cM (LOD score 5.70; P=.000001) and at 80 cM (LOD score 3.99; P=.00005) when a covariate measuring the number of affected individuals in the nuclear family was included. To evaluate further the contribution to the linkage signal from families with more than two affected relatives, we performed model-based linkage analysis with a recessive model and a range of penetrances, and we obtained maximum linkage at 70 cM (LOD score 3.16; P=.00007) with a penetrance of 0.3. We then estimated location by using GENEFINDER. The most likely location for a gene predisposing to IAs in the Finnish population is in a region with a 95% confidence interval of 11.6 cM (P=.00007) centered 2.0 cM proximal to D19S246.

Chromosomes, Human, Pair 19↗
PubMed2004

Detection of intracranial aneurysms with two-dimensional and three-dimensional multislice helical computed tomographic angiography.

OBJECTIVE: Computed tomographic angiography (CTA) has become a diagnostic method for the detection of intracranial aneurysms in cases of subarachnoid bleeding. We sought to evaluate the detection of aneurysms with CTA with a novel multislice helical computed tomographic scanner. METHODS: Prospectively, 179 patients underwent multislice CTA, followed by digital subtraction angiography (DSA) of both carotid arteries with or without the posterior circulation, DSA of one carotid artery with or without the posterior circulation, or DSA of the posterior circulation alone. The total number of carotid arteries studied was 298, and the number of vertebrobasilar arteries studied was 124. RESULTS: Of 178 aneurysms verified with DSA or intraoperatively, CTA failed to detect 7 aneurysms of 1 to 2 mm and 1 partially thrombosed, 4-mm aneurysm. The sensitivity and specificity of CTA for aneurysm detection were 0.96 and 0.97, respectively. CONCLUSION: The first generation of multislice computed tomographic technology does not improve CTA to surpass DSA for the detection of small aneurysms of 1 to 2 mm. In practice, however, CTA is superior as a fast noninvasive method without complications.

Angiography, Digital Subtraction↗
PubMed2004

Routine cerebral angiography after surgery for saccular aneurysms: is it worth it?

OBJECTIVE: The objective of this study was to determine whether an angiographically proven rate of saccular intracranial aneurysm occlusion after surgical clipping suggests that postoperative angiography should continue to be used routinely or should be supplanted by intraoperative angiography. These data also should establish a basis for comparing surgery with new endovascular methods of treatment. METHODS: During a 3.5-year period, a consecutive series of 622 patients (955 aneurysms, 808 of which were surgically clipped) who underwent postoperative angiography were studied retrospectively. This series comprised 493 ruptured and 315 unruptured aneurysms. RESULTS: Complete aneurysm closure was achieved in 88% of aneurysms, a neck remnant was discovered in 9%, and a fundus remnant was revealed in 3%. Of 493 ruptured aneurysms, 86% were completely occluded. Of 315 unruptured aneurysms, 91% were completely occluded. The results for clipping of complex aneurysms, i.e., posterior circulation or large to giant aneurysms, were significantly inferior to those for small and anterior circulation aneurysms. In one-third of the large and giant aneurysms, a part of the base was left intentionally because of calcifications or strong wall or to prevent occlusion of any branches. In the series, a significant 5% complication rate of major vessel occlusion was detected. CONCLUSION: Our retrospective analysis revealed that ruptured, posterior circulation, and large/giant aneurysms are more prone to incomplete clipping. Therefore, these aneurysms require postoperative if not intraoperative evaluation with angiography. Many clippings of anterior circulation aneurysms experience unexpected failures, which suggests that intraoperative angiography could be beneficial. This series, which has no selection bias, can be used as a basis to compare the results of other series reporting surgical or endovascular treatment.

Adult↗
PubMed2003

Familial intracranial aneurysms: an analysis of 346 multiplex Finnish families.

BACKGROUND AND PURPOSE: Genetic risk factors are considered important in the development, growth, and rupture of intracranial aneurysms; however, few have been identified. We analyzed intracranial aneurysm families with at least 2 affected persons and determined relationships between affected persons and assessed the inheritance patterns of aneurysms. METHODS: Families with > or =2 members with verified diagnoses of intracranial aneurysms were recruited from Kuopio and Helsinki, Finland. Families with a diagnosis of other heritable disorders that have associated intracranial aneurysms, such as autosomal dominant polycystic kidney disease, were excluded. RESULTS: We identified 346 Finnish multiplex families with 160 (46.2%) male and 186 (53.8%) female index cases. There were a total of 937 aneurysm cases, with an average of 2.7 cases per family. The majority of the families had only 2 affected relatives (n=206; 59.5%), although there were families with up to 6 (n=10), 7 (n=1), 8 (n=1), or 10 (n=2) affected persons. The affected relatives of the index cases included 108 sisters, 116 brothers, 105 parents, 30 children, 15 grandparents, 102 aunts or uncles, and 64 cousins. Of the 937 affected persons, 569 (60.7%) were alive and available for genetic analysis. Inheritance patterns consistent with autosomal recessiveness were observed in 198 (57.2%), autosomal dominance in 126 (36.4%), and autosomal dominance with incomplete penetrance in 19 (5.5%) of the families. CONCLUSIONS: The collection is the most extensive published to date and extends previous observations of familial aggregation that are consistent with a major gene effect.

Female↗
PubMed2003

Multiple aneurysms.

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Aneurysm, Ruptured↗