Antonino Russo

Ultrahigh-dose intraarterial infusion of verapamil through an indwelling microcatheter for medically refractory severe vasospasm: initial experience: Clinical article

OBJECT Vasospasm is one of the leading causes of morbidity and death following aneurysmal subarachnoid hemorrhage (SAH). Many patients suffer devastating strokes despite the best medical therapy. Endovascular treatment is the last line of defense for cases of medically refractory vasospasm. The authors present a series of patients who were treated with a prolonged intraarterial infusion of verapamil through an in-dwelling microcatheter. METHODS Over a 1-year period 12 patients with medically refractory vasospasm due to aneurysmal SAH were identified. Data were retrospectively collected, including age, sex, Hunt and Hess grade, Fisher grade, aneurysm location, aneurysm treatment, day of the onset of vasospasm, intracranial pressure, mean arterial pressures, intraarterial treatment of vasospasm, dosages and times of verapamil infusion, presence of a new ischemic area on CT scan, modified Rankin scale score at discharge and at the last clinical follow-up, and discharge status. RESULTS Twenty-seven treatments were administered. Between 25 and 360 mg of verapamil was infused per vessel (average dose per vessel 164.6 mg, range of total dose per treatment 70-720 mg). Infusion times ranged from 1 to 20.5 hours (average 7.8 hours). The number of treated vessels ranged from 1 to 7 per patient. The number of treatments per patients ranged from 1 to 4. There was no treatment-related morbidity or death. Blood pressure and intracranial pressure changes were transient and rapidly reversible. Among the 36 treated vessels, prolonged verapamil infusion was completely effective in 32 cases and partially effective in 4. Only 4 vessels required angioplasty for refractory vasospasm after prolonged verapamil infusion. There was no CT scanning evidence of new ischemic events in 9 of the 12 patients treated. At last clinical follow-up 6-12 months after discharge, 8 of 11 patients had a modified Rankin Scale score ≤2. CONCLUSIONS Prolonged intraarterial infusion of verapamil is a safe and effective treatment for medically refractory severe vasospasm and reduces the need for angioplasty in such cases.

Microsurgical and angiographic anatomy of middle cerebral artery aneurysms: prevalence and significance of early branch aneurysms.

OBJECTIVE To determine the prevalence of early branch aneurysms, characterize these lesions angiographically and anatomically, and determine their clinical significance. METHODS The authors conducted a retrospective review of 125 consecutive patients with a diagnosis of middle cerebral artery (MCA) aneurysm. Eighty-four patients harboring 100 MCA aneurysms were studied; 41 patients were excluded for lack of adequate imaging or for fusiform morphology of the aneurysm. Demographic characteristics including age, side, sex, subarachnoid hemorrhage, intracerebral hematoma, multiple aneurysms, and type of treatment were obtained. RESULTS The average patient age was 57.3 years (range, 29–79 yr); 69 were women and 15 were men. Fifty-eight were right MCA aneurysms and 42 were left aneurysms. Fourteen patients had multiple MCA aneurysms. Thirty-nine of 100 aneurysms were associated with subarachnoid hemorrhage. Twelve of 100 aneurysms were associated with an intracerebral hematoma. The average aneurysm sizes were 9.1 mm overall (range, 2.0–27.0 mm), 12.3 mm for ruptured aneurysms, and 7.5 mm for unruptured. There were 36 M1 bifurcation aneurysms, 39 early frontal branch aneurysms, 18 early temporal branch aneurysms, four lenticulostriate artery aneurysms, and three trifurcation aneurysms. CONCLUSION In our retrospective review, the majority of MCA aneurysms arose along the M1 segment proximal to the M1 bifurcation. Early frontal branch aneurysms were more common than typical M1 segment bifurcation aneurysms. M1 segment aneurysms arising from early frontal and early temporal branches have distinct anatomic features that impact surgical management and outcome. Understanding the relationship between the recurrent lenticulostriate arteries arising from the proximal segments of these early branches and the aneurysm neck should allow surgeons to avoid many postoperative ischemic complications when dealing with these challenging lesions.

Limitations of the transcallosal transchoroidal approach to the third ventricle.

OBJECT The aim of this study was to determine the anatomical limitations of the transcallosal transchoroidal approach to the third ventricle. METHODS Twenty-six formalin-fixed specimens were studied. Sagittal dissections were used to determine the anatomical relationships of the foramen of Monro, the angle of approach to landmarks, and placement of a callosotomy. Lateral ventricular dissections were performed to quantitate the forniceal anatomy. RESULTS The foramen of Monro was found 1.07+/-0.11 cm superior and slightly anterior to the mammillary bodies, 1.48+/-0.16 cm posterosuperior to the optic recess, and 2.26+/-0.16 cm anterosuperior to the aqueduct. Relative to the genu, a callosal incision 2.64+/-0.53 cm long and angled 37+/-4.3 degrees anterior was needed to access the aqueduct, and an incision 4.92+/-0.71 cm long and angled 49+/-7.4 degrees posterior was needed to access the optic recess. The fornix progressively widened within the lateral ventricle, from 1.25+/-0.63 mm at the foramen of Monro to >7 mm at 2 cm behind the foramen. Three zones of exposure were identified, requiring unique craniotomies, callosotomies, and angles of approach. The major limiting factors in the approach included the columns of the fornix anteriorly, the width of the fornix posteriorly, and the draining veins of the parietal cortex. The choroidal fissure opening was limited to 1.5 cm posterior to the foramen of Monro; this limited opening created an aperture effect that required an anterior-to-posterior angle, an anterior craniotomy, and an anteriorly placed callosotomy to access the posterior landmarks. In contrast, a posterior-to-anterior angle, posteriorly placed craniotomy, and posteriorly placed callosotomy were required to access anterior landmarks. CONCLUSIONS The transcallosal transchoroidal approach was ideally suited to access the foramen of Monro and the middle and posterior thirds of the third ventricle. Exposure of the anterior third ventricle was limited by the columns of the fornix and by the presence of parietal cortical draining veins.

The V2 segment of the vertebral artery: anatomical considerations and surgical implications

OBJECT Iatrogenic injury of the V(2) segment of the vertebral artery (VA) is a rare but serious complication and can be catastrophic. The purpose of this study was to characterize the relationship of the V(2) segment of the VA to the surrounding anatomical structures and to highlight the potential site and mechanisms of injury that can occur during common neurosurgical procedures involving the subaxial cervical spine. METHODS Ten adult cadaveric specimens (20 sides) were included in this study. Quantitative anatomical measurements between selected landmarks and the VA were obtained. In addition, lateral mass screws were placed bilaterally, from C-3 to C-7, reproducing either the Magerl technique or a modified technique. The safety angle, defined as the axial deviation from the screw trajectory needed to injure the VA, and the distance from the entry point to the VA were measured at each level for both techniques. RESULTS The VA coursed closer to the midline at C3-4 and C4-5 (mean distance [SD] 14.9 ± 1.1 mm) than at C2-3 or C5-6. Within the intertransverse space it coursed closer to the uncinate processes of the vertebral bodies (1.8 ± 1.1 mm) than to the anterior tubercle of the transverse processes (3.4 ± 1.6 mm). The distance between the VA and the uncinate process was less at C3-6 (1.3 ± 0.7 mm) than at C2-3 (3.3 ± 0.8 mm). The VA coursed on average at a distance of 11.9 ± 1.7 mm from the anterior and 4.2 ± 2.6 mm from the posterior aspect of the intervertebral disc space. Lateral mass screw angles were 25° lateral and 39.1° cranial for the Magerl technique, and 36.6° lateral and 46.1° cranial for the modified technique. The safety angle was greater and screw length longer when using this modified technique. CONCLUSIONS The relation of the V(2) segment of the VA to anterior procedures and lateral mass instrumentation at the subaxial cervical spine was reviewed in this study. A detailed anatomical knowledge of the V(2) segment of the VA combined with careful preoperative imaging is mandatory for safe cervical spine surgery.

Submandibular approach to the C2–3 disc level: microsurgical anatomy with clinical application

OBJECT Approaching the C2-3 disc level is challenging because of its location behind the mandible and the vital neurovascular structures overlying the area. The purpose of this study was to illustrate in a stepwise fashion the microsurgical anatomy of the submandibular approach to the C2-3 disc. METHODS Ten adult formalin-fixed cadaveric specimens (20 sides) were studied. Particular attention was paid to the structures limiting the exposure. The authors measured the distance between the inferior border of the mandible and the marginal mandibular branch of the facial nerve running inferior to the mandible, the distance between the horizontal segment of the hypoglossal nerve and the hyoid bone, and the distance between the horizontal segment of the hypoglossal nerve and the mandible. They compared the location of the superior laryngeal nerve with regard to the submandibular and the standard Smith-Robinson approaches. A clinical case illustrating the usefulness of the surgical technique in this region is presented. RESULTS The mean distance between the inferior border of the mandible and the lowest point of the marginal mandibular branch of the facial nerve was 6.7 +/- 1.69 mm. The hypoglossal nerves mean distance above the hyoid bone was 8.4 +/- 1.78 mm and below the mandible was 19.6 +/- 6.39 mm. The internal branch of the superior laryngeal nerve, with respect to the cervical spine, always entered the thyrohyoid membrane just inferior to the C-3 vertebral body. The superior laryngeal nerve was found to be an impediment to approaching the C2-3 disc through the standard Smith-Robinson approach. CONCLUSIONS The submandibular approach provides excellent exposure, with a perpendicular view of the C2-3 disc level. This approach is one of the options to be considered when dealing with high cervical pathologies.

Normal anatomical variations of the V3 segment of the vertebral artery: surgical implications

OBJECT The authors undertook this cadaveric and angiographic study to examine the microsurgical anatomy of the V₃ segment of the vertebral artery (VA) and its relationship to osseous landmarks. A detailed knowledge of these variations is important when performing common neurosurgical procedures such as the suboccipital craniotomy and the far-lateral approach and when placing atlantoaxial instrumentation. METHODS A total of 30 adult cadaveric specimens (59 sides) were studied using magnification × 3 to × 40 after perfusion of the arteries and veins with colored silicone. Seventy-three vertebral angiograms were also analyzed. The morphological detail of the V₃ segment was described and measured in both the cadavers and angiograms. Transarticular screws were placed into 2 cadavers and the relationship of the trajectory to the V₃ segment was analyzed. RESULTS The authors identified 4 sites along the V₃ segment that are anatomically the most likely to be injured during surgical approaches to the craniovertebral junction. In 35% of the cadaveric specimens the vertical portion of V₃ formed a posteriorly oriented loop that could be injured during surgical exposures of the dorsal surface of C-2. The mean distance from the midline to the most posteromedial edge of the loop was 25.6 ± 3.5 mm (range 20-35 mm) on the left side and 30.4 ± 3.8 mm (range 23-36 mm) on the right side. On lateral angiograms, this loop projected posteriorly, with a mean distance of 9.8 ± 3.5 mm (range 0-15.7 mm) on the right side and 11.7 ± 1.2 mm (range 10-13.6 mm) on the left side. The horizontal segment of V₃ can be injured when exposing the lower lateral occipital bone and when the C-1 arch is exposed. The mean distance from the inferior border of the occipital bone to the superior surface of the horizontal segment of V₃ was 6 ± 2.8 mm on the right side and 5.6 ± 2.3 mm on the left. In 12% of cases the authors found no space between the horizontal portion of V₃ and the occipital bone. The medial edge of the horizontal segment of V₃ was located 23 ± 5.5 mm (range 10-30 mm) from the midline on the right side and 24 ± 5.7 mm (range 15-32 mm) on the left side. The transition between the V₂-V₃ segments after exiting the C-2 vertebral foramen is the most likely site of injury when placing C1-2 transarticular screws or C-2 pars screws. CONCLUSIONS The normal variation of the V₃ segment of the VA has been described with quantitative measurements. An awareness of the anatomical variations and the relationships to the surrounding bony anatomy will aid in reducing VA injury during suboccipital approaches, exposure of the dorsal surfaces of C-1 and C-2, and when placing atlantoaxial spinal instrumentation.

Minimally invasive supracondylar transtubercular (MIST) approach to the lower clivus.

OBJECTIVE Drawbacks of the far-lateral approach to the lower clivus and pontomedullary region include the morbidity of a large incision extending into the cervical musculature and tedious exposure of the vertebral artery (VA), particularly when performing the transcondylar and transtubercular extensions. The authors describe a minimally invasive alternative to the far-lateral approach that has the potential to minimize operative morbidity and decrease the need for VA manipulation. METHODS The minimally invasive supracondylar transtubercular (MIST) and far-lateral supracondylar transtubercular (FLST) approaches were performed in 10 adult cadaveric specimens (20 sides). The microsurgical anatomy of each step and the surgical views were analyzed and compared. In addition, the endoscopic view through the MIST was examined in five fresh cadaveric specimens (10 sides). RESULTS The MIST approach provided exposure of the inferior-middle clivus, the anterolateral brainstem, and the premedullary cisterns, including the PICA-VA and vertebrobasilar junctions. The endoscope provided a clear view of cranial nerves III through XII, as well as the vertebrobasilar system. The FLST approach increased visualization of the anterolateral margin of the foramen magnum; otherwise, the surgical view is similar between the MIST and FLST approaches. CONCLUSIONS The MIST approach could be considered as a potential alternative to the FLST approach in the treatment of lesions involving the inferior and middle clivus, and anterolateral lower brainstem; it does not require a C1 laminectomy, significant disruption of the atlanto-occipital joint, nor extensive exposure of the extracranial VA. Moreover, the MIST approach is an ideal companion to endoscope-assisted neurosurgery.

High Anterior Cervical Approach to the Clivus and Foramen Magnum: A Microsurgical Anatomy Study

BACKGROUND: Surgical exposure of lesions located along the ventral foramen magnum (FM) and clivus poses a unique set of challenges to neurosurgeons. Several approaches have been developed to access these regions with varying degrees of exposure and approach-related morbidity. OBJECTIVE: To describe the microsurgical anatomy of the high anterior cervical approach to the clivus and foramen magnum, and describe novel skull base extensions of the approach. METHODS: Eight adult cadaveric specimens were included in this study. The high anterior cervical approach includes a minimal anterior clivectomy and its lateral skull base extensions: the extended anterior far-lateral clivectomy and the inferior petrosectomy. The microsurgical anatomy and exposure of the various extensions of the approach were analyzed. In addition, the capability of complementary endoscopy was evaluated. RESULTS: With proper positioning, the minimal anterior clivectomy exposed the vertebrobasilar junction, proximal basilar artery, anteroinferior cerebellar arteries, and 6th cranial nerve. The lateral skull base extensions provided access to the anterior FM, mid-lower clivus, and petroclival region, up to the Meckel cave, contralateral to the side of the surgical approach. CONCLUSION: The high anterior cervical approach with skull base extensions is an alternative to the classic approaches to the ventral FM and mid-lower clivus. A minimal anterior clivectomy provides access to the midline mid-lower clivus. The addition of an extended anterior far-lateral clivectomy and an inferior petrosectomy extends the exposure to the anterior FM and cerebellopontine angle lying anterior to the cranial nerves. The approach is also ideally suited for endoscopic-assisted techniques.

Abnormal Hemodynamics in Post Communicating Artery After Coil Embolization

Cerebral aneurysms are dilatations, or bulges, in blood vessels of the brain. They can occur in an endless variety of shapes and sizes and some of them can be harmless, while others can rupture and cause bleeding into the subarachnoid space, or the space between the brain and the skull. Once this occurs, a number of complications can develop such as hydrocephalus, vasospasm, stroke, and nerve damage, and the chance of survival is 50% [1]. It is estimated that approximately 2% of the United States population has cerebral aneurysms, and roughly 27,000 patients per year are reported to have ruptured aneurysms [2].Copyright