Vivek R. Deshmukh

Intraoperative Iso-C C-Arm Navigation in Craniospinal Surgery: The First 60 Cases

OBJECTIVE:The intraoperative Iso-C C-arm (Siremobil Iso-C 3D; Siemens Medical Solutions, Erlangen, Germany) provides a unique ability to acquire and view multi-planar three-dimensional images of intraoperative anatomy. Registration for intraoperative surgical navigation may be automated, thus simplifying the operative workflow. METHODS:Iso-C C-arm intraoperative fluoroscopy acquires 100 images, each of which must be 1.8 degrees in a circumferential fashion about an “isocentric” point in space. The system generates a high-resolution isotropic three-dimensional data set that is available immediately after the 90-second C-arm rotation. The data set is ported to the image-guided workstation, registration is immediate and automated, and the surgeon can navigate with millimetric accuracy. The authors prospectively examined data from the initial 60 patients examined with the Iso-C, among whom were cases of anterior and posterior spinal instrumentation from the occiput to the sacrum. Percutaneous and minimally invasive spinal and cranial procedures were also included. RESULTS:Automated registration for image-guided navigation was attainable for anterior and posterior cases from the cranial base and entire spine. In most cases, intraoperative postprocedural imaging with the Iso-C mitigated the need for postoperative imaging. CONCLUSION:Intraoperative Iso-C three-dimensional scanning allows real-time feedback during cranial base and spinal surgery and during procedures involving instrumentation. In most cases, it obviates the need for postoperative computed tomography. Its usefulness is in its simplicity, and it can be easily adapted to the operating room workflow. When coupled with intraoperative navigation, this new technology facilitates complex neurosurgical procedures by improving the accuracy, safety, and time of surgery.

Histopathological assessment of fatal ipsilateral intraparenchymal hemorrhages after the treatment of supraclinoid aneurysms with the Pipeline Embolization Device

OBJECT Delayed ipsilateral intraparenchymal hemorrhage has been observed following aneurysm treatment with the Pipeline Embolization Device (PED). The relationship of this phenomenon to the device and/or procedure remains unclear. The authors present the results of histopathological analyses of the brain sections from 3 patients in whom fatal ipsilateral intracerebral hemorrhages developed several days after uneventful PED treatment of supraclinoid aneurysms. METHODS Microscopic analyses revealed foreign material occluding small vessels within the hemorrhagic area in all patients. Further analyses of the embolic materials using Fourier transform infrared (FTIR) spectroscopy was conducted on specimens from 2 of the 3 patients. Although microscopically identical, the quantity of material recovered from the third patient was insufficient for FTIR spectroscopy. RESULTS FTIR spectroscopy showed that the foreign material was polyvinylpyrrolidone (PVP), a substance that is commonly used in the coatings of interventional devices. CONCLUSIONS These findings are suggestive of a potential association between intraprocedural foreign body emboli and post-PED treatment-delayed ipsilateral intraparenchymal hemorrhage.

Surgical Management of Cavernous Malformations Involving the Cranial Nerves

OBJECTIVETo analyze the indications and techniques pertinent to the treatment of cranial nerve (CN) cavernous malformations (CMs). METHODSCN CMs are lesions isolated to the CNs. CMs affecting the optic nerve (CN II), oculomotor nerve (CN III), facial/vestibulocochlear complex (CN VII and CN VIII), and hypoglossal nerve (CN XII) have been described. The records for six patients were reviewed with respect to lesion location, symptoms, surgical approach, and therapeutic considerations. This is the largest series of CMs isolated to CNs reported to date. RESULTSThree female patients and three male patients (age range, 28–76 yr; mean age, 41 yr) presented with six CN lesions; four lesions involved the optic chiasm and two involved CN VII and CN VIII. The patients with chiasmatic lesions presented with acute visual deterioration. Both patients with CN VII/CN VIII lesions exhibited acute hearing loss. The level of deterioration suggested CM hemorrhage. Orbitozygomatic craniotomies were performed for chiasmatic lesions, and retrosigmoid craniotomies were performed for cerebellopontine angle lesions. All patients experienced symptom improvement after surgery. One chiasmatic lesion recurred after 2 years and required resection. CONCLUSIONCN CMs present with site-specific symptoms and require complex surgical techniques for resection. These lesions are frequently symptomatic, because of the eloquence of the tissue of origin. Therefore, all CN CMs should be resected. Subtotal resection uniformly results in disease and symptom recurrence. CN CMs can be resected safely, with preservation of CN function.

Intra-arterial thrombolysis for acute ischemic stroke: preliminary experience with platelet glycoprotein IIb/IIIa inhibitors as adjunctive therapy.

OBJECTIVE:To evaluate the safety profile of platelet glycoprotein IIb/IIIa inhibitors administered as adjunctive therapy to patients with large-vessel occlusion and acute ischemic stroke refractory to pharmacological thrombolysis with recombinant tissue plasminogen activator (rtPA) and mechanical disruption, balloon angioplasty, or both. METHODS:Twenty-one patients (mean age, 62 yr; range, 29–88 yr) met the following criteria: 1) large-vessel occlusion and acute ischemic stroke syndrome at presentation, 2) failure to recanalize after administration of rtPA (intra-arterial and/or intravenous) with or without mechanical thrombolysis, and 3) subsequent treatment with IIb/IIIa inhibitors (intra-arterial or intravenous). RESULTS:Eleven patients had ischemia in the dominant hemisphere, 8 in the vertebrobasilar system, and 2 in the nondominant hemisphere. Twelve patients received intravenous rtPA without significant improvement; 9 patients were not candidates for intravenous rtPA. All patients received intra-arterial rtPA. The IIb/IIIa inhibitors were administered intravenously in 3 patients, intra-arterially in 16, and both intravenously and intra-arterially in 2. Balloon angioplasty was performed in 18 patients. Complete or partial recanalization was achieved in 17 of the 21 patients. After thrombolysis, 15 improved clinically. Three patients (14%) sustained an asymptomatic intracerebral hemorrhage after thrombolytic therapy. No patient was clinically worse after intervention. At last follow-up (mean, 8.5 mo), 13 patients were functionally independent (modified Rankin score, 0–3) and 8 were disabled or dead. CONCLUSION:IIb/IIIa inhibitors are an alternative for achieving recanalization. The risk of hemorrhage may be low. As part of an escalating protocol that includes pharmacological and mechanical thrombolysis, IIb/IIIa inhibitors may improve clinical outcomes.

An anatomical evaluation of the mini-supraorbital approach and comparison with standard craniotomies.

OBJECTIVE: To compare anatomically the surgical exposure provided by pterional (PT), orbitozygomatic (OZ), and minisupraorbital (SO) craniotomies. METHODS: Seven sides of six fixed cadaver heads injected with silicone were used. The mini-SO craniotomy followed by the PT and OZ approaches were performed sequentially. The bony flaps were attached with miniplates and screws, allowing easy conversion between the approaches. A frameless stereotactic device was used to calculate an area of surgical exposure and the angles of approach for six different anatomic targets. An image guidance system was used to demonstrate the limits of the surgical exposure for each technique. RESULTS: No significant differences were observed in the total area of surgical exposure when comparing the mini-SO (A = 1831.2 ± 415.3 mm2), PT (A = 1860.0 ± 617.2 mm2), and OZ approaches (A = 1843.3 ± 358.1 mm2; P > 0.05). Angular exposure was greater for the OZ and PT approaches than for the mini-SO approach, either in the vertical and horizontal axes, considering all of the six targets studied (P < 0.05). Except for the distal segment of the ipsilateral sylvian fissure, no practical differences in the limits of the exposure were detected. CONCLUSION: The mini-SO approach may offer a similar surgical working area compared with that provided by standard craniotomies and constitutes an excellent alternative to the OZ and PT craniotomies in selected patients. Selection should not be based primarily on the area to be exposed, but rather on the working angles that are anticipated to be required. The key point is to use the most adequate technique for a particular patient, rather than using a one-size-fits-all approach for all patients.

Long-term clinical and angiographic follow-up of unclippable wrapped intracranial aneurysms.

OBJECTIVE: This is the largest contemporary series examining long-term clinical and angiographic follow-up of unclippable wrapped intracranial aneurysms. METHODS: The presentation, location and shape of aneurysm, wrapping technique, outcome at discharge and last follow-up, and change in aneurysm at last angiographic follow-up were reviewed retrospectively in 74 patients with wrapped or clip-wrapped aneurysms. Patients in whom wrapping was used in conjunction with primary clipping were excluded. RESULTS: Of the 74 patients, 11 were lost to follow-up. The mean age of the remaining 63 patients (16 males, 47 females) was 56.5 years (range, 13–89 yr). Fifty-one aneurysms were located in the anterior circulation, and 17 were located in the posterior circulation. Fourteen patients presented with a ruptured aneurysm. Seventeen aneurysms were fusiform. Seven aneurysms were clip-wrapped, and 61 were wrapped with cotton. At discharge the Glasgow Outcome Scale (GOS) score was 5 in 54 patients and 4 in 5 patients. Two patients died from their presenting hemorrhage, and one from a medical comorbidity. The mean clinical follow-up was 44.1 months (range, 1–120 mo). One patient under clinical follow-up experienced subarachnoid hemorrhage. The mean angiographic follow-up of 34 patients was 41.8 months (range, 3–120 mo). During this follow-up period, no patient’s aneurysm changed in size or configuration. CONCLUSION: Wrapping or clip-wrapping of unclippable intracranial aneurysms is safe and seems to confer protection against aneurysmal growth or subarachnoid hemorrhage.

Microsurgical treatment of pediatric intracranial aneurysms: long-term angiographic and clinical outcomes.

BACKGROUNDPediatric aneurysms are rare and complex to treat. Long-term angiographic and clinical data after microsurgical or endovascular therapies are lacking. OBJECTIVETo study the clinical and radiographic outcomes in aneurysms in pediatric patients treated with microsurgery. METHODSBetween 1989 and 2005, 48 patients ≤ 18 years of age (28 boys, 20 girls; mean age, 12.3 years) were treated for intracranial aneurysms. Patient charts were reviewed retrospectively for age, presentation, type and location of aneurysm(s), surgical approach, complications, and clinical and angiographic outcomes. Rates of aneurysm recurrence and de novo formation were calculated. RESULTSSeventy-two aneurysms were treated. Presentations included incidental aneurysm (35%), aneurysmal subarachnoid hemorrhage (17%), stroke (13%), and traumatic subarachnoid hemorrhage (10%). Location was anterior circulation in 76% and posterior circulation in 24%. Twenty-eight (39%) were fusiform/dissecting, and 16 (23%) were giant. Most aneurysms were clipped directly. A vascular bypass with parent-vessel occlusion was used to treat 13 aneurysms (18%). Hypothermic circulatory arrest was used to treat 10 aneurysms (14%), all involving the basilar artery. The perioperative morbidity rate was 25%. There were no deaths. The long-term morbidity rate was 14%, and the mortality rate was 3%. Clinical outcome was favorable in 92% and 94% at discharge and follow-up, respectively (mean, 59 months; median, 32 months). At angiographic follow-up (mean, 53 months; median, 32 months), the annual recurrence rate was 2.6%, and the annual rate of de novo formation or growth was 7.8%. CONCLUSIONPediatric aneurysms require complex microsurgical techniques to achieve favorable outcomes. They leave higher rates of recurrence and de novo formation or growth than their adult counterparts, which mandates lifelong follow-up.

Diagnosis and Management of Pineocytomas

OBJECTIVE:Pineocytomas are associated with the most favorable prognosis of all pineal tumors. However, a subset of pineocytomas may have a predilection for recurrence and therefore behave aggressively. PATIENTS AND METHODS:Records of nine patients (five men, four women; mean age, 44 yr; range, 24–63 yr) with histologically diagnosed pineocytomas consecutively treated between 1990 and 2003 were reviewed retrospectively to identify factors predictive of aggressiveness. Eight patients presented with hydrocephalus and four with tectal compression. Three patients underwent gross total resection, and six underwent subtotal resection or biopsy. RESULTS:Three local recurrences necessitated reoperation. One recurrence involved the obex of the fourth ventricle. The mean time to recurrence was 3.5 years (range, 1–7 yr). There was no correlation between histological features and tumor recurrence. Patients undergoing radiosurgery showed stable or attenuated local disease (mean follow-up, 19.3 mo; range, 6–36 mo). Mean radiographic follow-up was 34 months (range, 6 mo to 10 yr). Mean clinical follow-up was 36 months (range, 1 mo to 10 yr). CONCLUSION:A subset of pineocytomas demonstrates the potential for symptomatic recurrence. We advocate an attempt at gross total tumor resection for all symptomatic patients with tectal plate compression, reserving radiosurgery for small, subtotally resected, or recurrent lesions. Patients must be followed closely for recurrence. Radiosurgery seems to be beneficial for local tumor control. Further investigation is needed to identify histological markers for pineocytomas that behave aggressively.

Quantification and comparison of telovelar and transvermian approaches to the fourth ventricle.

OBJECTIVE: To quantify the exposure to the fourth ventricle obtained with the telovelar and transvermian approaches. METHODS: The telovelar, with and without C1 posterior arch removal, and transvermian approaches were performed on six cadaveric heads. The area of surgical exposure was calculated from triangles formed by defined anatomic points. A robotic microscope was used to determine the “angle of approach” for the same points. RESULTS: The maximal allowable vertical angle of attack to the obex of the fourth ventricle was significantly greater with the telovelar approach than with the transvermian approach (P < 0.002), but there was no difference at the rostral fourth ventricle. The maximal allowable horizontal angle of attack at the level of the obex, Luschka, and rostral fourth ventricle was significantly greater with the telovelar than with the transvermian approach (P < 0.001). Removal of the C1 posterior arch with the telovelar approach significantly increased the vertical angle of approach to the obex (P < 0.001) and rostral aspect of the fourth ventricle (P = 0.005) compared with the telovelar alone. The telovelar approach with C1 arch removal offered a larger working area than the transvermian approach (P < 0.001). CONCLUSION: Except for the vertical angle to the rostral aspect of the fourth ventricle, the telovelar approach provides greater angle of exposure in all planes than the transvermian approach. Removal of the C1 posterior arch obviates this sole advantage of the transvermian approach. The telovelar approach offers a corridor through noneloquent arachnoid planes and a safe and capacious working environment.

Monorail snare technique for the recovery of stretched platinum coils : Technical case report

OBJECTIVE AND IMPORTANCE: Coil stretching represents a potentially hazardous technical complication not infrequently encountered during the embolization of cerebral aneurysms. Often, the stretched coil cannot be advanced into the aneurysm or withdrawn intact. The operator is then forced to attempt to retract the damaged coil, which may result in coil breakage, leaving behind a significant length of potentially thrombogenic stretched coil material within the parent vessel. To overcome this problem, we devised a technique to snare the distal, unstretched, intact portion of the platinum coil by use of the indwelling microcatheter and stretched portion of the coil as a monorail guide. CLINICAL PRESENTATION: We have used this technique successfully in four patients to snare coils stretched during cerebral aneurysm embolization. Three of these patients were undergoing Neuroform (Boston Scientific/Target, Fremont, CA) stent-supported coil embolization of unruptured aneurysms. In all cases, the snare was advanced easily to the targeted site for coil engagement by use of the microcatheter as a monorail guide. Once the intact distal segment of the coil was ensnared, coil removal was uneventful, with no disturbance of the remainder of the indwelling coil pack or Neuroform stent. TECHNIQUE: A 2-mm Amplatz Goose Neck microsnare (Microvena Corp., White Bear Lake, MN) was placed through a Prowler-14 microcatheter (Cordis Corp., Miami, FL). The hub of the indwelling SL-10 microcatheter (Boston Scientific, Natick, MA) was then cut away with a scalpel, leaving the coil pusher wire intact, and removed. The open 2-mm snare was then advanced over the outside of the coil pusher wire and microcatheter. The snare and Prowler-14 microcatheter were then advanced into the guiding catheter (6- or 7-French) as a unit over the indwelling SL-10 microcatheter. By use of the SL-10 microcatheter and coil as a “monorail” guide, the snare was advanced over and beyond the microcatheter and the stretched portion of the coil until the snare was in position to engage the distal unstretched coil. At this point, the snare was then closed around the intact portion of the coil, and the microcatheters, snare, and coil were removed as a unit. CONCLUSION: The monorail snare technique represents a fast, safe, and easy method by which a stretched coil can be removed.