bluuebunny/crossref_metadata_2025 huggingface dataset:
Complementary Use of Computed Tomographic Angiography in Treatment Planning for Posterior Fossa Subarachnoid Hemorrhage
Authors: Carvi y Nievas Mario N. , Haas Eberhard , Höllerhage Hans-Georg , Drathen Christian
Published: July 2004

OBJECTIVE

The goal of this study was to determine whether the complementary use of computed tomographic angiographic (CTA) assessments would provide additional benefits in the evaluation and treatment of ruptured vertebrobasilar artery aneurysms.

METHODS

In the past 4.5 years, 35 patients with an infratentorial dominant pattern of subarachnoid hemorrhage were complementarily examined with CTA scanning, after undergoing one or more three-dimensional rotational projection digital subtraction angiographic (DSA) studies. The results of these studies were interpreted by the treating neurosurgeon and an interventional radiologist, to examine the usefulness of the findings for the detection of aneurysms and to determine the grade of parent artery vascular filling and the optical definition of the aneurysm. This information provided additional benefits for case management.

RESULTS

Thirty-three aneurysms were detected. For 10 patients, no aneurysm was identified in repeated examinations with the two methods. We detected only 16 of the 25 ruptured aneurysms (64%) on the first DSA scans and, even with repeated examinations, 6 aneurysms were not clearly identified with this technique. CTA scanning revealed the ruptured aneurysms in 25 cases and demonstrated increased vascular filling and improved optical definition of the aneurysms, compared with DSA scanning, in 12 cases (48%). The information obtained from the CTA scans allowed the selection of five patients for endovascular treatment and facilitated the surgical procedures in five cases.

CONCLUSION

Complementary CTA examination of the vertebrobasilar complex provides a higher rate of aneurysm detection and improves the optical definition and anatomic projection of these aneurysms, compared with DSA scanning alone. This facilitates therapeutic decision-making (surgical versus endovascular procedures) and allows neurosurgeons to use more restricted surgical exposures.
Endoscopic Augmented Reality Navigation System for Endonasal Transsphenoidal Surgery to Treat Pituitary Tumors: Technical Note
Authors: Kawamata Takakazu , Iseki Hiroshi , Shibasaki Takao , Hori Tomokatsu
Published: July 2004

OBJECTIVE

Endoscopes have been commonly used in transsphenoidal surgery to treat pituitary tumors, to compensate for the narrow surgical field. Although many navigation systems have been introduced for neurosurgical procedures, there have been few reports of navigation systems for endoscopic operations. This report presents our recently developed, endoscopic, augmented reality (AR) navigation system.

METHODS

The technology is based on the principles of AR environment technology. The system consisted of a rigid endoscope with light-emitting diodes, an optical tracking system, and a controller. The operation of the optical tracking system was based on two sets of infrared light-emitting diodes, which measured the position and orientation of the endoscope relative to the patient's head. We used the system during endonasal transsphenoidal operations to treat pituitary tumors in 12 recent cases.

RESULTS

Anatomic, “real,” three-dimensional, virtual images of the tumor and nearby anatomic structures (including the internal carotid arteries, sphenoid sinuses, and optic nerves) were superimposed on real- time endoscopic live images. The system also indicated the positions and directions of the endoscope and the endoscopic beam in three-dimensional magnetic resonance imaging or computed tomographic planes. Furthermore, the colors of the wire-frame images of the tumor changed according to the distance between the tip of the endoscope and the tumor. These features were superior to those of conventional navigation systems, which are available only for operating microscopes.

CONCLUSION

The endoscopic AR navigation system allows surgeons to perform accurate, safe, endoscope-assisted operations to treat pituitary tumors; it is particularly useful for reoperations, in which midline landmarks may be absent. We consider the AR navigation system to be a promising tool for safe, minimally invasive, endonasal, transsphenoidal surgery to treat pituitary tumors.
Angioplasty for Intracranial Symptomatic Vertebrobasilar Ischemia
Authors: Gress Daryl R. , Smith Wade S. , Dowd Chris F. , Halbach Van V. , Finley Randall J. , Higashida Randall T.
Published: July 2004

OBJECTIVE

Although anterior circulation disease has both medical and surgical treatment options, management of vertebrobasilar disease has predominantly had only medical options. Some patients remain symptomatic despite medical treatment, and angioplasty has been demonstrated to relieve critical stenoses. However, the relative safety and effectiveness of medical and surgical treatments is not clearly known. This report reviews the clinical characteristics, indications, and procedural risks of intracranial angioplasty in a series of patients with symptomatic posterior circulation ischemia.

METHODS

All patients undergoing angioplasty for critical intracranial vertebral or basilar artery stenosis at the University of California at San Francisco Medical Center between June 1986 and July 1999 were included in a retrospective record review. Clinical features and procedural complications were recorded.

RESULTS

Angioplasty was performed on 25 vessel lesions in 25 patients in whom medical therapy had failed. The patients ranged in age from 50 to 87 years. Of the 25 stenoses, 10 were intracranial vertebral, 9 vertebrobasilar junction, and 6 basilar in location. Angioplasty was effective in reducing the degree of stenosis by more than 40% in all 25 vessels. The overall risk of stroke or death was 28%, and the risk of disabling stroke or death was 16%.

CONCLUSION

Intracranial posterior circulation angioplasty is effective in the reduction of stenosis and can be performed with relative safety. Angioplasty can be considered as a treatment option in patients with recurrent ischemic symptoms despite medical therapy.
Spinal Epidural Abscesses: Clinical Manifestations, Prognostic Factors, and Outcomes
Authors: Soehle Martin , Wallenfang Thomas
Published: July 2004

OBJECTIVE

This study was performed to evaluate the clinical manifestations and prognostic factors for outcomes among patients with nontuberculous spinal epidural abscesses.

METHODS

The records and magnetic resonance imaging/computed tomographic results for patients treated between 1994 and 2000 were retrospectively evaluated. Outcomes were assessed after 11 months, using scores ranging from 0 (dead) to 4 (no neurological deficits).

RESULTS

All 25 patients (mean age, 62 yr) underwent surgery and subsequently received antibiotics. Back/neck pain (72% of patients), leukocytosis (64%), fever (60%), and motor deficits (56%) were the most common symptoms at admission. Outcomes were assessed as poor for 40% of the patients and as good (no deficit or independently ambulatory) for 60%. Low leg muscle strength grades (r = 0.68, P < 0.001) and high white blood cell (WBC) counts (r = −0.56, P = 0.006) at admission were significantly correlated with low outcome scores. From the time of admission until 14 days after surgery, the poor-outcome group exhibited significantly (P < 0.005) higher WBC counts, compared with the good-outcome group. The same was true for C-reactive protein levels, with the exception that no differences between groups were observed until 8 days after surgery. Factors such as cervicothoracic abscess locations (P = 0.041), lower limb motor deficits (P = 0.005), complete paralysis (P = 0.005), and WBC counts of more than 14,000 cells/μl (P = 0.049) at admission were observed to be prognostic for poor outcomes.

CONCLUSION

Surgical decompression combined with antimicrobial therapy remains the recommended treatment. In addition to abscess locations and motor deficits, inflammatory markers such as WBC counts and C-reactive protein levels are prognostic for outcomes.
Facet Fusion in the Lumbosacral Spine: A 2-year Follow-up Study
Authors: Park Youn-Kwan , Kim Jong-Hyun , Oh Jae In , Kwon Taek-Hyun , Chung Hung-Seob , Lee Ki-Chan
Published: July 2004

OBJECTIVE

A clinical and radiological follow-up study was undertaken to assess the safety, efficacy, and complication rate associated with instrumented facet fusion of the lumbar and lumbosacral spine.

METHODS

This study involved 99 patients with degenerative lumbar disorders who were treated surgically at the authors' neurosurgical department and followed for more than 2 years. Eighty-two patients underwent one-level fusion for the treatment of Grade I or II degenerative spondylolisthesis and accompanying spinal canal stenosis (44 patients) or recurrent disc herniation (38 patients). Seventeen patients underwent two-level fusion for the treatment of either double instances of the above indications (seven patients) or concurrent stenosis at the adjacent level (10 patients).

RESULTS

There were no technique-related complications. The overall 2-year success rate of fusion was 96%; the success rates by fusion type were 99% in one-level fusions and 88% in two-level fusions. Degenerative spondylolisthesis had the highest success rate at 100%, whereas the success rate in patients who had not responded to previous discectomy was 93%. Patients with concurrent stenosis experienced the lowest success rate: 80%. Excellent or good clinical results were obtained for 85% of patients with one-level fusions and for 65% of patients with two-level fusions.

CONCLUSION

Instrumented facet fusion alone is a simple, safe, and effective surgical option for the treatment of patients with single-level disorders, especially patients with degenerative spondylolisthesis.
Comparison of the Mini-open versus Laparoscopic Approach for Anterior Lumbar Interbody Fusion: A Retrospective Review
Authors: Kaiser Michael G. , Haid Regis W. , Subach Brian R. , Miller Jay S. , Smith C. Dan , Rodts Gerald E.
Published: July 2004

OBJECTIVE

The anterior lumbar interbody fusion (ALIF) procedure has become an accepted fusion technique for treating patients with degenerative disorders of the lumbar spine. Many consider laparoscopic ALIF to be the least invasive approach. A modification of the open laparotomy—the “mini-open” approach—is an attractive alternative. In this retrospective review, a comparison of these two ALIF approaches is presented.

METHODS

We conducted a retrospective review of 98 patients who underwent ALIF procedures between 1996 and 2001 in which either a mini-open or a laparoscopic approach was used. Patient demographics, intraoperative parameters, length of hospitalization, and technique-related complications associated with the use of these two approaches were compared. The subset of patients who underwent L5–S1 ALIF procedures was analyzed separately. Statistical analysis was conducted with χ2 and Student's paired t tests.

RESULTS

Between 1996 and 2001, a total of 98 patients underwent ALIF. A laparoscopic approach was used in 47 of these patients, and the mini-open technique was used in the other 51 patients. Operative preparation and procedure time were longer with the use of a laparoscopic approach, and significantly greater during L5–S1 ALIF procedures (P < 0.05). A marginal but significant increase in length of stay was observed after mini-open ALIF procedures (P < 0.05). The immediate postoperative complication rate was greater after mini-open ALIF procedures, 17.6 versus 4.3% (P < 0.05); however, the rate of retrograde ejaculation was higher in the laparoscopic group, 45 versus 6% (P < 0.05).

CONCLUSION

Both the laparoscopic and mini-open techniques are effective approaches to use when performing ALIF procedures. On the basis of the data obtained in this retrospective review, the laparoscopic approach does not seem to have a definitive advantage over the mini-open exposure, particularly in an L5–S1 ALIF procedure. In our opinion, the mini-open approach possesses a number of theoretical advantages; however, the individual surgeon's preference ultimately is likely to be the dictating factor.
Image-guided Endoscopic Transnasal Removal of Recurrent Pituitary Adenomas
Authors: Lasio Giovanni , Ferroli Paolo , Felisati Giovanni , Broggi Giovanni
Published: July 2004

OBJECTIVE

To assess the role that neuronavigation plays in assisting endoscopic transsphenoidal reoperations for recurrent pituitary adenomas.

METHODS

During a 45-month period, 19 endoscopic endonasal transsphenoidal reoperations were performed for recurrent pituitary adenomas. In 11 of 19 patients, the procedure was performed with the aid of an optically guided system. Clinical records were reviewed retrospectively, with attention to the following: comparison of baseline clinical data, the duration of surgery, and the postoperative course and complications of both image-guided and non-image-guided endoscopic reoperations. In addition, to test the reliability of the neuronavigation system, we made measurements of intraoperative accuracy in five additional transnasal endoscopic procedures in “virgin” noses and sphenoidal sinuses.

RESULTS

In both groups studied, we found no difference with regard to either morbidity or mortality, which were null. The mean setup time was 13 minutes shorter in non-image-guided procedures (P = 0.021), and the operative time was 36 minutes shorter in image-guided procedures (P = 0.038). No other statistically significant differences were found between the two groups. In all cases, we found that the system performed without malfunction. Continuous information regarding instrument location and trajectory was provided to the surgeon. Measurements of the intraoperative accuracy in the axial, coronal, and sagittal planes indicated a mean intraoperatively verified system error of 1.6 ± 0.6 mm.

CONCLUSION

Neuronavigation can be applied during endonasal transsphenoidal endoscopic surgery and requires a minimal amount of time. It makes reoperation easier, faster, and probably safer.
Treatment of Giant Intracranial Aneurysms with Saphenous Vein Extracranial-to-Intracranial Bypass Grafting: Indications, Operative Technique, and Results in 29 Patients
Authors: Jafar Jafar J. , Russell Stephen M. , Woo Henry H.
Published: July 2004

OBJECTIVE

The treatment of giant intracranial aneurysms is a challenge because of the limitations and difficulty of direct surgical clipping and endovascular coiling. We describe the indications, surgical technique, and complications of saphenous vein extracranial-to-intracranial bypass grafting followed by acute parent vessel occlusion in the management of these difficult lesions.

METHODS

Between January 1990 and December 1999, 29 patients with giant intracranial aneurysms underwent 30 saphenous vein bypass grafts followed by immediate parent vessel occlusion. There were 11 men and 18 women with a mean follow-up period of 62 months. Twenty-five patients harbored aneurysms involving the internal carotid artery, 2 had middle cerebral artery aneurysms, and 2 had aneurysms in the basilar artery. Serial cerebral or magnetic resonance angiograms were obtained to assess graft patency and aneurysm obliteration.

RESULTS

All 30 aneurysms were excluded from the cerebral circulation, with 28 vein grafts remaining patent. Two patients had graft occlusions: one because of poor runoff and the other because of misplacement of a cranial pin during a bypass procedure on the contralateral side. Other surgical complications included one death from a large cerebral infarction, homonymous hemianopsia from thrombosis of an anterior choroidal artery after internal carotid artery occlusion, and temporary hemiparesis from a presumed perforator thrombosis adjacent to a basilar aneurysm.

CONCLUSION

With appropriate attention to surgical technique, a saphenous vein extracranial-to-intracranial bypass followed by acute parent vessel occlusion is a safe and effective method of treating giant intracranial aneurysms. A high rate of graft patency and adequate cerebral blood flow can be achieved. Thrombosis of perforating arteries caused by altered blood flow hemodynamics after parent vessel occlusion may be a continuing source of complications.
Partial Labyrinthectomy Petrous Apicectomy Approach to the Petroclival Region: An Anatomic and Technical Study
Authors: Chanda Amitabha , Nanda Anil
Published: July 2004

OBJECTIVE

The petroclival region generally is thought to be an inaccessible area in the intracranial compartment. A number of ways of reaching this area during surgery have been described, including the presigmoid petrosal approach. The partial labyrinthectomy petrous apicectomy approach is a relatively new approach to this region and is a variant of the presigmoid petrosal approach. This study aims to demonstrate the technique and the microsurgical anatomy of the partial labyrinthectomy petrous apicectomy approach and to provide a quantitative study of its exposure to compare it with other common approaches to this region, particularly the presigmoid petrosal approach.

METHODS

Bilateral stepwise dissections were performed on 15 formalin-fixed and dye-injected cadaveric heads (30 sides) under ×3 to ×40 magnification. A temporal craniotomy was performed after a complete mastoidectomy. A partial labyrinthectomy and petrous apicectomy were performed next. The amount of dura exposed was measured before and after the partial labyrinthectomy and the petrous apicectomy. By measuring the angles of exposure, the approach was examined to analyze how much increased access was gained.

RESULTS

This approach provided wide exposure to the petroclival region, the cerebellopontine angle, Meckel's cave, the cavernous sinus, and the prepontine region. On average, there was an increase of 10.8 mm in horizontal exposure as compared with the retrolabyrinthine approach. The average angle of vision achieved with the clival pit as the target was 58.9 degrees. In most of the specimens, an area from the IIIrd to the IXth cranial nerves was easily visible without any significant brain retraction. A high jugular bulb did not reduce the exposure.

CONCLUSION

The partial labyrinthectomy petrous apicectomy approach converts two narrow tunnels into a wide corridor. It increases the angle of exposure markedly, providing easy and excellent exposure of the otherwise difficult-to-access petroclival region, and it may also preserve hearing.
Familial Medulloblastoma: Case Report of One Family and Review of the Literature
Authors: von Koch Cornelia S. , Gulati Mittul , Aldape Kenneth , Berger Mitchel S.
Published: July 2004

OBJECTIVE AND IMPORTANCE

Medulloblastoma is the most common malignant brain tumor and the most common malignant solid tumor in children. Most medulloblastomas are sporadic, but rare familial forms have been described. To the best of our knowledge, only 10 case reports of familial medulloblastoma have been published. A variety of candidate genes have been suggested to be involved in familial medulloblastomas. However, the exact pathogenesis and genetics involved in familial medulloblastoma remain unknown.

CLINICAL PRESENTATION

We describe the presentation of medulloblastoma in two siblings (one of each sex) and their great-uncle. The three cases differ with regard to age at onset and pathological subtype of medulloblastoma.

INTERVENTION OR TECHNIQUE

Immunostaining of tissue blocks for gene products involved in medulloblastoma differed in the two siblings for β-catenin and was similar with staining for gli.

CONCLUSION

This article is only the second report in the literature to address the genetics of familial medulloblastoma in the absence of characterized conditions such as Li-Fraumeni's cancer syndrome and basal cell nevus, Rubinstein-Taybi's, and Turcot's syndromes. The discrepancy in β-catenin staining in the two siblings suggests that the two tumors differentiated through divergent pathways. We briefly summarize all published cases of familial medulloblastoma and review the literature on the genes involved in medulloblastoma formation.
Endovascularly Treated Cerebral Aneurysm Using Guglielmi Detachable Coils Acting as a Nidus for Brain Abscess Formation Secondary to Salmonella Bacteremia: Case Report
Authors: Kirollos Ramez W. , Bosma Jark J.D. , Radhakrishnan Jayakumar , Pigott Timothy D.J.
Published: July 2004

OBJECTIVE AND IMPORTANCE

Intracranial infections related to the various foreign materials used to secure intracranial aneurysms are extremely rare. The lack of neoendothelium formation across the necks of aneurysms, which is particularly prone to occur when the sac is incompletely packed by Guglielmi detachable coils (GDC), results in the absence of isolation of the coils from the circulation. Colonization of GDCs, which act as a foreign-body nidus after hematogenous spread from infections with bacteremia, may result in localized intracranial infection.

CLINICAL PRESENTATION

A 55-year-old woman developed meningitis and a brain abscess surrounding a giant aneurysm that was treated endovascularly with GDC 31/2 years earlier. Four weeks before she sought care, she experienced an infective illness with proven Salmonella bacteremia. Salmonella group D was isolated from cerebrospinal fluid.

INTERVENTION

The patient was treated successfully with long-term cephalosporin therapy. Follow-up imaging studies revealed regression of the abscess.

CONCLUSION

This case suggests that the GDC acted as a colonized foreign body, resulting in the surrounding abscess formation after infection with Salmonella bacteremia. Alternatively, the reaction of the surrounding tissue to the GDC was the predisposing factor and acted as the nidus for the abscess formation.
Cervical Spinal Cord Compression Attributable to a Calcified Intervertebral Disc in a Patient with X-linked Hypophosphatemic Rickets: Case Report and Review of the Literature
Authors: Soehle Martin , Casey Adrian T.H.
Published: July 2004

OBJECTIVE AND IMPORTANCE

X-linked hypophosphatemic rickets is a common inherited phosphate-wasting disorder, but it is a rare cause of spinal cord compression. We present the first reported case of a calcified intervertebral disc causing spinal canal stenosis in X-linked hypophosphatemic rickets.

CLINICAL PRESENTATION

A 44-year-old woman presented with paresthesia of her left arm and a loss of grip in both hands. Magnetic resonance imaging revealed a calcified intervertebral disc, as well as a posterior osteophytic bar causing marked cervical cord compression at C6/C7.

INTERVENTION

An anterior cervical discectomy at C6/C7 and fusion with autologous bone graft were performed. The patient then exhibited significant improvement.

CONCLUSION

A review of the 16 published cases demonstrates that thickening of the vertebral laminae, facet joint hypertrophy, and ossification of the intervertebral discs, posterior longitudinal ligament, and/or ligamentum flavum contribute to spinal canal stenosis in X-linked hypophosphatemic rickets. Those changes are caused by the disease itself and are unlikely to be related to long-term vitamin D treatment. Eleven of 16 patients were reported to have experienced favorable outcomes after surgery.
Covered Stent-graft Repair of the Brachiocephalic Arteries: Technical Note
Authors: Amar Arun Paul , Teitelbaum George P. , Giannotta Steven L. , Larsen Donald W.
Published: July 2004

OBJECTIVE

The use of a covered stent-graft to repair disruptions of the cervical carotid and vertebral arteries is described. This device maintains vessel patency while effectively excluding pseudoaneurysms, arteriovenous fistulae, and other breaches in the integrity of the arterial wall.

METHODS

Patient 1 bled from a large rent in the proximal common carotid artery as a result of tumor invasion. Patient 2 developed a vertebral arteriovenous fistula after a stab injury to the neck. Patient 3 developed cerebral infarction and an enlarging pseudoaneurysm of the internal carotid artery, also after a stab wound to the neck.

RESULTS

All three patients were treated with the Wallgraft endoprosthesis (Boston Scientific, Watertown, MA). In each case, the vessel wall defect was repaired while antegrade flow through the artery was preserved or restored. No neurological complications occurred as a result of stent-graft deployment.

CONCLUSION

Covered stent-grafts offer an alternative to endovascular occlusion of the parent vessel, thereby expanding the therapeutic options for patients with extracranial cerebrovascular disease. These three cases highlight the usefulness and versatility of these devices for endoluminal reconstruction of the brachiocephalic vasculature.
Clinical and Hemodynamic Responses to Balloon Test Occlusion of the Straight Sinus: Technical Case Report
Authors: Houdart Emmanuel , Saint-Maurice Jean-Pierre , Boissonnet Hervé , Bonnin Philippe
Published: July 2004

OBJECTIVE AND IMPORTANCE

Surgical sacrifice of the straight sinus may be performed during intracranial tumor resection. Sacrifice of the straight sinus is associated with an unpredictable risk of venous infarction. We describe a patient with a falcine meningioma who underwent endovascular balloon test occlusion of the straight sinus before surgical resection.

CLINICAL PRESENTATION

A 48-year-old woman presented with symptoms resulting from a 4-cm-diameter meningioma in the left occipital region. Along its inferior margin, the tumor abutted the straight sinus. Cerebral angiography demonstrated occlusion of the posterior one-third of the superior sagittal sinus but patency of the straight sinus.

TECHNIQUE

A 4-mm angioplasty balloon was directed into the straight sinus via the right jugular vein. In addition to clinical assessments, the pressure within the proximal straight sinus, upstream from the balloon, was measured before and during inflation. Severe headaches followed balloon inflation, and the pressure in the proximal straight sinus increased 18 mm Hg. With balloon deflation, the clinical and hemodynamic findings immediately returned to normal. On the basis of these findings, the straight sinus was preserved during surgery.

CONCLUSION

This technique is straightforward and allows some assessment of the physiological responses and individual tolerance to sinus occlusion before surgery.
Trapping and Revascularization for a Dissecting Aneurysm of the Proximal Posteroinferior Cerebellar Artery: Technical Case Report and Review of the Literature
Authors: Ali Mir Jafer , Bendok Bernard R. , Tawk Rabih G. , Getch Christopher C. , Batjer H. Hunt
Published: July 2004

OBJECTIVE AND IMPORTANCE

Subarachnoid hemorrhage caused by an isolated dissection of the proximal portion of the posteroinferior cerebellar artery (PICA) is a rare problem. The optimal treatment to use for patients presenting with this clinical scenario varies and therefore is controversial in the literature. We report a patient in whom this problem was treated effectively with trapping of the diseased segment and revascularization of the PICA. We report this case to review this rare topic and to present our perspective on the indications for and the effectiveness of trapping and revascularization for proximal PICA dissections that cause hemorrhage.

CLINICAL PRESENTATION

A 55-year-old man was transferred to our institution and admitted for Hunt and Hess Grade IV subarachnoid hemorrhage, which improved to Hunt and Hess Grade III after ventricular drainage. Imaging revealed the source of the hemorrhage to be a pseudoaneurysm related to the dissection of the proximal portion of the PICA.

INTERVENTION

Three days after the initial bleeding episode, we operated on the patient. After the occipital artery was prepared for bypass, the diseased segment was trapped. The occipital artery-to-PICA anastomosis was then immediately performed distal to the trapped segment.

CONCLUSION

On the basis of our experience, the literature regarding this topic, and the anatomy of the perforators of the PICA, we think that the best treatment for a pseudoaneurysm located within the first three segments of the PICA is trapping of the diseased segment followed by revascularization distal to the trapped segment. This approach should prevent rehemorrhage and should avoid iatrogenic ischemic complications of the brainstem.
Radiosurgery for Treatment of Recurrent Intracranial Hemangiopericytomas
Authors: Sheehan Jason , Kondziolka Douglas , Flickinger John , Lunsford L. Dade
Published: July 2004

OBJECTIVE

Hemangiopericytomas are highly aggressive meningeal tumors with tendencies for recurrence and metastasis. The purpose of this retrospective, single-institution review was to evaluate the efficacy and role of stereotactic radiosurgery in the management of recurrent hemangiopericytomas.

METHODS

We reviewed data for patients who underwent stereotactic radiosurgery at the University of Pittsburgh between 1987 and 2001. Fourteen patients underwent radiosurgery for 15 discrete tumors. Prior treatments included transsphenoidal resection (n = 1), craniotomy and resection (n = 27), embolization (n = 1), and conventional radiotherapy (n = 7). Clinical and radiological responses were evaluated. Follow-up periods varied from 5 to 76 months (mean, 31.3 mo; median, 21 mo). The mean radiation dose to the tumor margin was 15 Gy.

RESULTS

Seventy-nine percent of patients (11 of 14 patients) with recurrent hemangiopericytomas demonstrated local tumor control after radiosurgery. Twelve of 15 tumors (i.e., 80%) dramatically decreased in size on follow-up imaging scans. Regional intracranial recurrences were retreated with radiosurgery for two patients (i.e., 15%); neither of those two patients experienced long-term tumor control. Local recurrences occurred 12 to 75 months (median, 21 mo) after radiosurgery. Local tumor control and survival rates at 5 years after radiosurgery were 76 and 100%, respectively (Kaplan-Meier method). We could not correlate prior irradiation or tumor size with tumor control. Twenty-nine percent of the patients (4 of 14 patients) developed remote metastases. Radiosurgery did not seem to offer protection against the development of intra- or extracranial metastases.

CONCLUSION

Gamma knife radiosurgery provided local tumor control for 80% of recurrent hemangiopericytomas. When residual tumor is identified after resection or radiotherapy, early radiosurgery should be considered as a feasible treatment modality. Despite local tumor control, patients are still at risk for distant metastasis. Diligent clinical and radiological follow-up monitoring is necessary.
Role of Venous Drainage in Cerebral Arteriovenous Malformation Surgery, as Related to the Development of Postoperative Hyperperfusion Injury
Authors: Schaller Carlo , Urbach Horst , Schramm Johannes , Meyer Bernhard
Published: July 2004

OBJECTIVE

To elucidate the role of venous drainage in cerebral arteriovenous malformation (AVM) surgery, with respect to the development of postoperative hyperperfusion injury.

METHODS

For 52 patients with supratentorial AVMs, cortical capillary oxygenation (SaO2) was assessed intraoperatively, before and after resection, in the vicinity of the AVMs, by using a microspectrophotometric method. Assessed areas were defined as being related to feeding arteries or draining veins or as distant areas. Patients were divided into three groups on the basis of postoperative angiographic findings, as follows: Group 1, all former draining veins preserved (8 patients); Group 2, ≥1 former draining vein visible (12 patients); Group 3, no former draining veins visible (32 patients). Patients and SaO2 values were pooled and compared by using paired and unpaired t tests (P < 0.05). Venous circulation times were calculated from digital subtraction angiography films.

RESULTS

The postresectional relative increases in SaO2 values were highest in draining vein areas (+40.8%, compared with +25% in feeder areas and +25.5% in distant areas). Five postoperative hyperemic complications occurred (9.6%), none in Group 1 (with all draining veins preserved), two (16.7%) in Group 2, and three (9.4%) in Group 3 (with all draining veins occluded). The lowest preresectional SaO2 values (31.7 ± 6.2%) were measured in the drainer areas of the five patients who subsequently developed hyperperfusion injuries. Among those patients, postresectional increases in SaO2 values were significantly greater in drainer areas (+167.8%) than in feeder areas (+28.3%) or distant areas (+25.8%). Postoperative venous circulation times in former draining veins in Group 2 were significantly greater than those in Group 1 (8.9 ± 1.5 s versus 6.3 ± 0.6 s). Circulation times in normal veins in the five patients with hyperperfusion injury increased from 5.6 ± 1.0 seconds (preoperatively) to 8.4 ± 1.9 seconds (postoperatively).

CONCLUSION

Postoperative hyperperfusion injury after resection of cerebral AVMs can be explained on the basis of unconstrained arterial inflow into cortical areas, which are rendered hypoxic/ischemic by longstanding preoperative venous hypertension. The risk for postoperative breakthrough complications seems higher in the presence of multiple draining veins, which also participate in the physiological venous drainage system of the ipsilateral hemisphere.
Preoperative Evaluation of Neurovascular Compression in Patients with Trigeminal Neuralgia by Use of Three-dimensional Reconstruction from Two Types of High-resolution Magnetic Resonance Imaging
Authors: Akimoto Hideaki , Nagaoka Tsukasa , Nariai Tadashi , Takada Yoshiaki , Ohno Kikuo , Yoshino Norio
Published: July 2004

OBJECTIVE

To assess the value of three-dimensional (3-D) images reconstructed from 3-D constructive interference in steady state (3-D-CISS) and 3-D fast inflow with steady-state precession (3-D-FISP) images for the visualization of neurovascular compression in patients with trigeminal neuralgia.

METHODS

Twenty-four consecutive patients with trigeminal neuralgia underwent preoperative 3-D-FISP and 3-D-CISS imaging. 3-D reconstruction of nerves and vessels was performed with the use of a volume-rendering method. We compared the 3-D reconstructed images with intraoperative findings.

RESULTS

3-D-CISS and 3-D-FISP images scanned from the same position clearly delineated the trigeminal nerve and vessels. 3-D reconstructed images showed the spatial relationship between the trigeminal nerve and causative vessels. The responsible arteries were identified from the 3-D reconstructed images, which closely simulated the microscopic operative view.

CONCLUSION

3-D reconstructions from two types of high-resolution magnetic resonance images (3-D-CISS and 3-D-FISP) are very useful for creating preoperative simulations and in deciding whether to perform surgery in patients with trigeminal neuralgia.
Anterior Communicating Artery Aneurysms
Authors: Riina Howard A. , Lemole G. Michael , Spetzler Robert F.
Published: July 2004

ANTERIOR COMMUNICATING ARTERY aneurysms are complex lesions for which surgical success requires extensive preoperative and intraoperative planning. Adherence to the tenets of aneurysm surgery, including vascular control and preservation of perforating arteries, is essential for their exclusion from the circulation.
Ruptured Aneurysm of the Ophthalmic Artery Trunk Demonstrated by Three-dimensional Rotational Angiography: Case Report
Authors: Yanaka Kiyoyuki , Matsumaru Yuji , Kamezaki Takao , Nose Tadao
Published: July 2004

OBJECTIVE AND IMPORTANCE

Aneurysms arising from the ophthalmic artery are extremely rare, compared with carotid-ophthalmic aneurysms arising from the wall of the internal carotid artery. We present a very unusual type of aneurysm arising from the ophthalmic artery itself.

CLINICAL PRESENTATION

A 54-year-old man presented with a sudden onset of headache and was transferred to a local hospital. Computed tomography demonstrated subarachnoid hemorrhage around the left anterior clinoid process, but digital subtraction angiography failed to localize the source of the hemorrhage. The patient was referred to our hospital for further evaluation and treatment. Conventional cerebral angiography did not reveal the source of the hemorrhage, but three-dimensional rotational angiography clearly demonstrated an aneurysm arising from the ophthalmic artery trunk, apart from the internal carotid artery.

INTERVENTION

The patient underwent microsurgical clipping of the aneurysm via a left pterional craniotomy. The aneurysm originated from the bifurcation of the ophthalmic artery and a perforating artery to the optic nerve. The aneurysm was successfully obliterated, and the postoperative course was uneventful.

CONCLUSION

This report is the first to describe a case of a ruptured aneurysm arising from the ophthalmic artery trunk. We discuss the clinical significance of an aneurysm at this site, as well as the role of three-dimensional rotational angiography in determining the source of subarachnoid hemorrhage.
Basilar Trunk Aneurysm Surgically Treated with Anterior Petrosectomy and External Carotid Artery-to-Posterior Cerebral Artery Bypass: Technical Note
Authors: Terasaka Shunsuke , Itamoto Koji , Houkin Kiyohiro
Published: July 2004

OBJECTIVE

We discuss a detailed surgical technique, its indications, and potential pitfalls in its use.

METHODS

A surgical procedure combining Kawase's anterior petrosectomy and external carotid artery-to-posterior cerebral artery high-flow bypass was performed for the treatment of a patient with a fusiform basilar trunk aneurysm.

RESULTS

Follow-up angiography revealed the successful obliteration of the aneurysm and that the graft was functioning well. Late ischemic complications, however, occurred 5 weeks after surgery.

CONCLUSION

Kawase's approach is a versatile option for safe vascular reconstruction of the posterior cerebral artery and exposure of a basilar trunk aneurysm in the upper clival region. Although, theoretically, a high-flow bypass might decrease the risk of hemodynamic ischemia, it does not prevent thromboembolic complications.
Endoscope-assisted Microsurgery for Intracranial Aneurysms
Authors: Kalavakonda Chandrasekar , Sekhar Laligam N. , Ramachandran Pranatartiharan , Hechl Peter
Published: July 2004

OBJECTIVE

We discuss the role of the endoscope in the microsurgical treatment of intracranial aneurysms, analyzing its benefits, risks, and disadvantages.

METHODS

This was a prospective study of 55 patients with 79 aneurysms, treated between July 1998 and June 2001, for whom the endoscope was used as an adjunct in the microsurgical treatment of their lesions. Seventy-one aneurysms were located in the anterior circulation, and eight were located in the posterior circulation. Thirty-seven patients presented with subarachnoid hemorrhage. Eighteen patients had unruptured aneurysms, of whom 5 presented with mass effect, 2 presented with transient ischemic attacks, and 11 were without symptoms. In all cases, the endoscope was used in addition to microsurgical dissection and clipping (sometimes before clipping, sometimes during clipping, and always after clipping), for observation of the neck anatomic features and perforators and verification of the optimal clip position. Intraoperative angiography was performed for all patients after aneurysm clipping.

RESULTS

In the majority of cases, the endoscope was very useful for the assessment of regional anatomic features. It allowed better observation of anatomic features, compared with the microscope, for 26 aneurysms; in 15 cases, pertinent anatomic information could be obtained only with the endoscope. The duration of temporary clipping of the parent artery was significantly reduced for two patients. The clip was repositioned because of a residual neck or inclusion of the parent vessel during aneurysm clipping in six cases, and the clip position was readjusted because of compression of the optic nerve in one case. One patient experienced a small aneurysm rupture that was directly related to use of the endoscope, but this was easily controlled, with no sequelae. For many patients, the combination of the neuro-endoscope and the micro-Doppler probe made intraoperative angiography redundant.

CONCLUSION

“Endoscope-assisted microsurgery” is a major advance in the microsurgical treatment of intracranial aneurysms; the endoscope allows better observation of regional anatomic features because of its magnification, illumination, and ability to “look around corners.”
Nonconvulsive Status Epilepticus after Subarachnoid Hemorrhage
Authors: Dennis Lyle J. , Claassen Jan , Hirsch Lawrence J. , Emerson Ronald G. , Connolly E. Sander , Mayer Stephan A.
Published: July 2004

OBJECTIVE

Although in-hospital seizures have been reported for 3 to 24% of patients with aneurysmal subarachnoid hemorrhage (SAH), nonconvulsive status epilepticus (NCSE) has not been previously described. We sought to determine the frequency and clinical features of NCSE among comatose patients with SAH.

METHODS

Between November 1997 and February 2000, we performed continuous electroencephalographic (cEEG) monitoring for at least 24 hours for all patients with aneurysmal SAH who were treated in our neurological intensive care unit and exhibited unexplained coma or neurological deterioration. NCSE was diagnosed when cEEG monitoring demonstrated continuous or repetitive electrographic seizures exceeding 1 hour in duration. Refractory NCSE was treated aggressively with intravenous anticonvulsant administration and continuous-infusion midazolam therapy.

RESULTS

Of 233 patients with SAH who survived the first 48 hours of hospitalization, 101 were stuporous or comatose at some point during their hospitalization. Twenty-six of those patients underwent cEEG monitoring, and eight were diagnosed as having NCSE, an average of 18 days (range, 5–38 d) after SAH. All eight patients were receiving prophylactic anticonvulsant therapy. Four patients were persistently comatose and four demonstrated deterioration to stupor or coma; only one exhibited overt tonicoclonic activity. A worst Hunt and Hess grade of IV or V, older age, ventricular drainage, and cerebral edema on computed tomographic scans were identified as risk factors for NCSE (all P < 0.01). NCSE was successfully terminated for five patients (63%), but only one experienced clinical improvement, which was transient; all eight patients eventually died after a period of prolonged coma.

CONCLUSION

cEEG monitoring detected NCSE for 8% of patients with SAH and otherwise unexplained coma or neurological deterioration. The seizures were highly refractory to therapy, and the prognosis for these patients was extremely poor. Routine postoperative cEEG monitoring of patients with SAH who are at high risk for NCSE, allowing earlier diagnosis and treatment, offers the best chance of improving the outcomes for patients with this disorder.
Spinal Cord Mapping as an Adjunct for Resection of Intramedullary Tumors: Surgical Technique with Case Illustrations
Authors: Quinones-Hinojosa Alfredo , Gulati Mittul , Lyon Russell , Gupta Nalin , Yingling Charles
Published: July 2004

OBJECTIVE

Resection of intramedullary spinal cord tumors may result in transient or permanent neurological deficits. Intraoperative somatosensory evoked potentials (SSEPs) and motor evoked potentials are commonly used to limit complications. We used both antidromically elicited SSEPs for planning the myelotomy site and direct mapping of spinal cord tracts during tumor resection to reduce the risk of neurological deficits and increase the extent of tumor resection.

METHODS

In two patients, 3 and 12 years of age, with tumors of the thoracic and cervical spinal cord, respectively, antidromically elicited SSEPs were evoked by stimulation of the dorsal columns and were recorded with subdermal electrodes placed at the medial malleoli bilaterally. Intramedullary spinal cord mapping was performed by stimulating the resection cavity with a handheld Ojemann stimulator (Radionics, Burlington, MA). In addition to visual observation, subdermal needle electrodes inserted into the abductor pollicis brevis-flexor digiti minimi manus, tibialis anterior-gastrocnemius, and abductor halluces-abductor digiti minimi pedis muscles bilaterally recorded responses that identified motor pathways.

RESULTS

The midline of the spinal cord was anatomically identified by visualizing branches of the dorsal medullary vein penetrating the median sulcus. Antidromic responses were obtained by stimulation at 1-mm intervals on either side of the midline, and the region where no response was elicited was selected for the myelotomy. The anatomic and electrical midlines did not precisely overlap. Stimulation of abnormal tissue within the tumor did not elicit electromyographic activity. Approaching the periphery of the tumor, stimulation at 1 mA elicited an electromyographic response before normal spinal cord was visualized. Restimulation at lower currents by use of 0.25-mA increments identified the descending motor tracts adjacent to the tumor. After tumor resection, the tracts were restimulated to confirm functional integrity. Both patients were discharged within 2 weeks of surgery with minimal neurological deficits.

CONCLUSION

Antidromically elicited SSEPs were important in determining the midline of a distorted cord for placement of the myelotomy incision. Mapping spinal cord motor tracts with direct spinal cord stimulation and electromyographic recording facilitated the extent of surgical resection.
Cerebral Venous Steal: Blood Flow Diversion with Increased Tissue Pressure
Authors: Pranevicius Mindaugas , Pranevicius Osvaldas
Published: July 2004

PURPOSE

Flow in areas with increased tissue pressure is described by a Starling resistor and is determined by the inflow pressure (Pi), the external pressure (Pe), and the outflow or venous pressure (Pv). Flow is in Zone 1 at Pe > Pi > Pv, Zone 2 at Pi > Pe > Pv, and Zone 3 at Pi > Pv > Pe. A focal tissue pressure increase after stroke or trauma may lead to a transition from Zone 1 or 2 in the center to Zone 3 in the periphery. We hypothesize that the coexistence of different zones may lead to steal-like blood flow diversion in the perifocal area.

CONCEPT

We used a lumped-parameter model of two parallel Starling resistors with a common inflow. The first resistor, with higher Pe, represented the area with increased tissue pressure. The second resistor, with Pe′ = 0, represented the surrounding area. We evaluated the effects of venous pressure on the flow distribution between the two Starling resistors.

RATIONALE

The model demonstrated blood flow diversion toward the second Starling resistor with low external pressure. High inflow resistance facilitates this “steal.” Flow diversion is caused by effective outflow pressure differences for the Starling resistors (Pe for the first and Pv for the second). The venous pressure increase equilibrates the effective backpressure and decreases flow diversion. When the venous pressure equals the external tissue pressure, blood flow diversion (cerebral venous steal) is abolished. Although increased venous pressure causes global flow reduction, it may restore flow to more than 50% of baseline values in areas of increased tissue pressure.

DISCUSSION

Cerebral venous steal is a potential cause of secondary brain injury in areas of increased tissue pressure. It can be eliminated with increased venous pressure. Increased venous pressure may recruit the collapsed vascular network and correct perifocal perfusion maldistribution. This resembles how positive end expiratory pressure recruits collapsed airways and decreases the ventilation/perfusion mismatch.