Category: Surgical technique

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Lateral supracerebellar transtentorial approach for petroclival meningiomas: operative technique and outcome

J Neurosurg 115:49–54, 2011. DOI: 10.3171/2011.2.JNS101759

The retrosigmoid intradural suprameatal approach with the patient in a semisitting position is an effective alternative to transpetrosal approaches for the treatment of petroclival meningiomas. The authors have made a simple modification to the retrosigmoid intradural suprameatal approach by using the lateral oblique position and preferentially dividing the tentorium with limited drilling of the suprameatal bone, which is termed the “lateral su- pracerebellar transtentorial approach.”

Methods. Twenty-six patients with petroclival meningiomas surgically treated via the lateral supracerebellar transtentorial approach were analyzed. All tumors had most of their bulk in the posterior fossa with some degree of extension into the middle fossa and/or Meckel cave. The patient is placed in the lateral oblique position, and a standard retrosigmoid craniotomy is performed. The tentorium medial to the trigeminal nerve is incised toward the free edge, which improves exposure to the petroclival region without extensive resection of the suprameatal petrous bone.

Results. Gross-total resection was achieved in 11 patients (42%). Ten patients (38%) underwent subtotal resection, and 5 patients (19%) underwent partial resection. There was no incidence of operative death, and the postoperative permanent morbidity rate was 15%. All patients except one did well postoperatively and were independent at the time of their last follow-up examinations.

Conclusions. The lateral supracerebellar transtentorial approach provides the simplest and safest access to the petroclival region. It offers an advantageous approach to petroclival meningiomas exclusively located in the posterior fossa with minimal extension into the Meckel cave and middle fossa.

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Superciliary Keyhole Approach for Small Unruptured Aneurysms in Anterior Cerebral Circulation

Neurosurgery 68[ONS Suppl 2]:ons300–ons309, 2011 DOI: 10.1227/NEU.0b013e3182124810

Neurovascular surgeons have been trying to find a solution to the problem of surgical invasiveness by applying minimally invasive keyhole approaches.

OBJECTIVE: To evaluate the feasibility and surgical outcomes of a superciliary keyhole approach for unruptured intracranial aneurysms (UIAs) as an alternative to a pterional approach.

METHODS: The authors report on a consecutive series of patients who underwent a superciliary approach for clipping UIAs smaller than 15 mm arising at the supraclinoid internal carotid artery (ICA), A1 segment, anterior communicating artery (ACoA), and M1 segment including the middle cerebral artery (MCA) bifurcation. The data were compared with a historical control group (n = 90) who underwent a pterional approach for UIAs.

RESULTS: A total of 120 aneurysms were successfully clipped in 102 patients with a mean age of 58 years. There was no direct mortality related to the surgery, and only 1 (1.0%) patient developed significant morbidity adversely affecting the Glasgow Outcome Scale score. The superciliary approach demonstrated statistically significant advantages over the pterional approach, including a shorter operative duration (mean, 120 min), no intraoperative blood transfusion, and extremely rare postoperative epidural hemorrhages. In addition, temporalis atrophy was rare and palsy of the frontalis persisting more than 6 months only occurred in 6 patients (5.9%) and was resolved within 2 years. The overall cosmetic outcome was excellent.

CONCLUSION: A superciliary approach can be a reasonable alternative to a pterional approach for small (,15 mm) UIAs arising at the supraclinoid ICA, A1, ACoA, and M1 segment including the MCA bifurcation.

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Use of Movable High-Field-Strength Intraoperative Magnetic Resonance Imaging With Awake Craniotomies for Resection of Gliomas: Preliminary Experience

Neurosurgery 69:194–206, 2011 DOI: 10.1227/NEU.0b013e31821d0e4c

Awake craniotomy with electrocortical mapping and intraoperative magnetic resonance imaging (iMRI) are established techniques for maximizing tumor resection and preserving function, but there has been little experience combining these methodologies.

OBJECTIVE: To report our experience of combining awake craniotomy and iMRI with a 1.5-T movable iMRI for resection of gliomas in close proximity to eloquent cortex.

METHODS: Twelve patients (9 male and 3 female patients; age, 32-60 years; mean, 41 years) undergoing awake craniotomy and iMRI for glioma resections were identified from a prospective database. Assessments were made of how these 2 modalities were integrated and what impact this strategy had on safety, surgical decision making, workflow, operative time, extent of tumor resection, and outcome.

RESULTS: Twelve craniotomies were safely performed in an operating room equipped with a movable 1.5-T iMRI. The extent of resection was limited because of proximity to eloquent areas in 5 cases: language areas in 3 patients and motor areas in 2 patients. Additional tumor was identified and resected after iMRI in 6 patients. Average operating room time was 7.9 hours (range, 5.9-9.7 hours). Compared with preoperative neurological function, immediate postoperative function was stable/improved in 7 and worse in 5; after 30 days, it was stable/improved in 11 and worse in 1.

CONCLUSION: Awake craniotomy and iMRI with a movable high-field-strength device can be performed safely to maximize resection of tumors near eloquent language areas.

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Application of intraoperative indocyanine green videoangiography to brain tumor surgery

Acta Neurochir (2011) 153:1487–1495. DOI 10.1007/s00701-011-1046-x

Videoangiography using indocyanine green (ICG) has been used in the ophthalmologic field for a long time. It was introduced to the neurosurgical field several years ago but has been limited to vascular surgeries. We applied ICG videoangiography to brain tumor surgery and evaluated the usefulness.

Methods Twenty-three patients with a brain tumor who underwent microsurgical resection were analyzed. The pathological diagnosis was meningioma in 15 patients, metastasis in three, glioma in three, and hemangioblastoma in two. A microscope with a special filter and infrared excitation light to illuminate the operating field was used in this study. The intravascular fluorescence was imaged with a video camera attached to the microscope. ICG was injected intravenously with the dose of 5–25 mg, and overall, ICG was injected intraoperatively 32 times.

Results ICG videoangiography allowed for an excellent evaluation of blood flow in the tumoral and peri-tumoral vessels both before and after the resection in all cases.

Conclusions ICG videoangiography is a useful method for monitoring blood flow in the exposed vessels during microsurgery for a brain tumor. This noninvasive method is simple, safe, cost-effective, and easily repeatable. Before resection, it provides information on the tumoral and peritumoral circulation including sequential visualization of vessels or direction of the blood flow. After resection, it checks the patency of the peri-tumoral vessels and is especially useful for the vein. This ICG videoangiography can be an alternative tool to intraoperative angiography or Doppler ultrasonography in selective cases.

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How I do it: cervical lateral mass screw fixation

Acta Neurochir. DOI 10.1007/s00701-011-1068-4

Cervical lateral mass screw fixation is indicated for the treatment of cervical subaxial C3-C7 lesions associated with instability.

Method The authors first describe the surgical anatomy of the subaxial cervical posterior approach. Then the Magerl technique is detailed. In particular, tricks to avoid complications are presented. The ideal screw entry point, direction, size and exit point are mentioned. A surgical video, artist’s drawings and a radiological case report are included.

Conclusion The Magerl technique is a safe and effective lateral mass fixation technique. Respecting anatomical landmarks is crucial to avoid nerve root, vertebral artery and facet joint injury.

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Endonasal endoscopic resection of esthesioneuroblastoma: the Johns Hopkins Hospital experience and review of the literature

Neurosurg Rev. DOI 10.1007/s10143-011-0329-2

Esthesioneuroblastoma is an uncommon malignant tumor originating in the upper nasal cavity. The surgical treatment for this tumor has traditionally been via an open craniofacial resection. Over the past decade, there has been tremendous development in endoscopic techniques.

In this report, we performed a retrospective analysis of patients with esthesioneuroblastomas treated with a purely endonasal endoscopic approach and resection at the Johns Hopkins Hospital between January 2005 and April 2010.

A total of eight patients with esthesioneuroblastoma, five men and three women, were identified. Six patients were treated for primary disease, and two were treated for tumor recurrence. The modified Kadish staging was A in one patient (12.5%), B in two patients (25%), C in four patients (50%), and D in one patient (12.5%). All patients had a complete resection with negative intraoperative margins. One patient had intraoperative hypertension; there were no perioperative complications. With a mean follow-up of over 27 months, all patients are without evidence of disease. In addition, we reviewed the literature and identified several overlapping case series of patients with esthesioneuroblastoma treated via a purely endoscopic technique.

Our series adds to the growing experience of expanded endonasal endoscopic surgery in the treatment of skull base tumors including esthesioneuroblastoma. Longer follow-up on a larger number of patients is required to further demonstrate the utility of endoscopic approaches in the management of this malignancy.

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Laparoscopy-assisted ventriculoperitoneal shunt surgery: personal experience and review of the literature

Neurosurg Rev (2011) 34:363–371. DOI 10.1007/s10143-011-0309-6

Ventriculoperitoneal shunting is a widely accepted technique for the treatment of hydrocephalus. The standard procedure to insert the peritoneal catheter requires an abdominal incision, muscle dissection, and opening of the peritoneum. A number of complications related to the abdominal surgical phase have been reported. Laparoscopy-assisted ventriculoperitoneal shunting is a valid alternative procedure that reduces surgical trauma.

We describe our experience and review the literature. A total of 30 laparoscopically guided ventriculoperitoneal shunting procedures were performed between January 2007 and June 2008, in collaboration with a general surgeon experienced in laparoscopy. Of these procedures, 25 were new shunt placements and 5 were revisions. Data about operative time, outcome, and complications were registered and compared with a group of 30 patients treated by means of standard laparotomy in the period 2005–2007. Laparoscopic shunt placement was successful in all patients. Operative duration, complications, and postoperative pain were all lower in patients treated by laparoscopy as compared to the laparotomy. In the laparoscopic group, an earlier peristalsis, quicker mobilization, and better cosmetic results were also noted.

Laparoscopy in both ventriculoperitoneal shunt placement and revision is a safe, effective, and minimally invasive technique. It ensures proper abdominal placement of the distal catheter under direct vision allowing confirmation of its patency.

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Tubular Diskectomy vs Conventional Microdiskectomy for the Treatment of Lumbar Disk Herniation: 2-Year Results of a Double-Blind Randomized Controlled Trial

Neurosurgery 69:135–144, 2011 DOI: 10.1227/NEU.0b013e318214a98c

Transmuscular tubular diskectomy has been introduced to increase the rate of recovery, although evidence is lacking.

OBJECTIVE: To evaluate the 2-year results of tubular diskectomy compared with conventional microdiskectomy.

METHODS: Three hundred twenty-eight patients with persistent leg pain caused by lumbar disk herniation were randomly assigned to undergo tubular diskectomy (167 patients) or conventional microdiskectomy (161 patients). Main outcome measures were scores from Roland-Morris Disability Questionnaire for Sciatica, Visual Analog Scale for leg pain and low-back pain, and Likert self-rating scale of global perceived recovery.

RESULTS: On the basis of intention-to-treat analysis, there was no significant difference between tubular diskectomy and conventional microdiskectomy in Roland-Morris Disability Questionnaire for Sciatica scores during 2 years after surgery (between-group mean difference [∆] = 0.6; 95% confidence interval [CI], 20.3-1.6). Patients treated with tubular diskectomy reported more leg pain (∆ = 3.3 mm; 95% CI, 0.2-6.2) and more lowback pain (∆ = 3.0 mm; 95% CI, 20.2-6.3) than those patients treated with conventional microdiskectomy. At 2 years, 71% of patients assigned to tubular diskectomy documented a good recovery vs 77% of patients assigned to conventional microdiskectomy (odds ratio, 0.76; 95% CI, 0.45-1.28; P = .35). Repeated surgery rates within 2 years after tubular diskectomy and conventional microdiskectomy were 15% and 10%, respectively (P = .22).

CONCLUSION: Tubular diskectomy and conventional microdiskectomy resulted in similar functional and clinical outcomes. Patients treated with tubular diskectomy reported more leg pain and low-back pain, although the differences were small and not clinically relevant.

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Quantitative fluorescence in intracranial tumor: implications for ALA-induced PpIX as an intraoperative biomarker

J Neurosurg 115:11–17, 2011. DOI: 10.3171/2011.2.JNS101451

Accurate discrimination between tumor and normal tissue is crucial for optimal tumor resection. Qualitative fluorescence of protoporphyrin IX (PpIX), synthesized endogenously following d-aminolevulinic acid (ALA) administration, has been used for this purpose in high-grade glioma (HGG). The authors show that diagnostically significant but visually imperceptible concentrations of PpIX can be quantitatively measured in vivo and used to discriminate normal from neoplastic brain tissue across a range of tumor histologies.

Methods. The authors studied 14 patients with diagnoses of low-grade glioma (LGG), HGG, meningioma, and metastasis under an institutional review board–approved protocol for fluorescence-guided resection. The primary aim of the study was to compare the diagnostic capabilities of a highly sensitive, spectrally resolved quantitative fluorescence approach to conventional fluorescence imaging for detection of neoplastic tissue in vivo.

Results. A significant difference in the quantitative measurements of PpIX concentration occurred in all tumor groups compared with normal brain tissue. Receiver operating characteristic (ROC) curve analysis of PpIX concentration as a diagnostic variable for detection of neoplastic tissue yielded a classification efficiency of 87% (AUC = 0.95, specificity = 92%, sensitivity = 84%) compared with 66% (AUC = 0.73, specificity = 100%, sensitivity = 47%) for conventional fluorescence imaging (p < 0.0001). More than 81% (57 of 70) of the quantitative fluorescence measurements that were below the threshold of the surgeon’s visual perception were classified correctly in an analysis of all tumors.

Conclusions. These findings are clinically profound because they demonstrate that ALA-induced PpIX is a targeting biomarker for a variety of intracranial tumors beyond HGGs. This study is the first to measure quantitative ALA-induced PpIX concentrations in vivo, and the results have broad implications for guidance during resection of intracranial tumors.

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Clipping of MCA aneurysms: how I do it

Acta Neurochir (2011) 153:1361–1366. DOI 10.1007/s00701-011-1063-9

Aneurysms located at the middle cerebral artery bifurcation remain a clear neurosurgical indication. We detail here the steps necessary to enable safe surgery for Sylvian fissure aneurysms.

Methods: An angiogram with 3D reconstruction is obtained and reviewed intraoperatively, just prior to the skin incision. During the exposure, the cistern is kept open by small cottonoids, thereby avoiding brain retraction. Continuous monitoring of MEPs along with ICG microscopic angiofluorescence allows for detection of vascular compromise. Intraoperative angiography with 3D reconstruction allows for immediate correction of less than satisfactory surgical outcome.

Conclusions Careful planning of surgical strategy followed by a minimally invasive technique (with continuous neuro-monitoring) ensures safe surgery. The availability of intra-operative radiological guidance allows for optimal management.

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Stitched sling retraction technique for microvascular decompression: procedures and techniques based on an anatomical viewpoint

Neurosurg Rev (2011) 34:373–380. DOI 10.1007/s10143-011-0310-0

The success of microvascular decompression stitched sling retraction techniques for treating trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GPN), focusing on the stitching point for slinging the offending artery in the appropriate direction.

Between January 2007 and March 2009, 28 patients with TN, 5 patients with HFS, and 3 patients with GPN underwent MVD with a sling retraction technique. In cases of TN, MVD was performed using the infratentorial lateral supracerebellar approach, and the offending superior cerebellar artery was superomedially transposed with a sling stitched to the tentorium cerebelli. In cases of HFS, MVD was performed using the lateral suboccipital infrafloccular approach, and the offending vertebral artery was superolaterally transposed with a sling stitched to the petrous dura. In cases of GPN, MVD was performed using the transcondylar fossa approach, in which the posterior inferior cerebellar artery was inferolaterally mobilized with a sling secured to the jugular tubercle. No patient suffered recurrence in the follow-up period.

For the sling retraction technique to be performed successfully, it is important for a stitch to be placed at a suitable site to sling the offending vessel in the intended direction. An appropriate surgical approach must be used to obtain a sufficient operative field for performing the stitching procedures safely.

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Lateral Supraorbital Approach Applied to Anterior Clinoidal Meningiomas: Experience With 73 Consecutive Patients

Neurosurgery 68:1632–1647, 2011 DOI: 10.1227/NEU.0b013e318214a840

Anterior clinoidal meningiomas (ACMs) are a subgroup of meningiomas accounting for less than 10% of supratentorial meningiomas.

OBJECTIVE: To assess the reliability and safeness of the lateral supraorbital approach (LSO) to remove ACMs.

METHODS: Between September 1997 and October 2009, a total of 73 ACM patients were operated on at the Department of Neurosurgery, Helsinki University Central Hospital, by the senior author (J.H.). We retrospectively analyzed the clinical data, radiological findings, surgical treatment, histology, and outcome of patients, and discuss the operative technique.

RESULTS: Seventy-three patients were operated on by applying the LSO approach. Apparently complete removal was achieved in 57 patients (78%). Anterior clinoidectomy was performed in 21 cases. Preexisting visual deficit improved in 11 of 39 patients and worsened in 4; 3 had de novo visual deficit. At 3 months after discharge, 60 (82%) patients had a good recovery, 9 (12%) patients were moderately disabled, 1 presented with severe disability, and 3 (4%) patients died of surgery-related causes. Sixteen (22%) patients had residual tumors, 6 of which required reoperation. During the median followup of 36 months (range, 3-146), tumor recurred in 3 patients: 2 were followed-up and 1 was reoperated on.

CONCLUSION: ACMs can be removed via the LSO approach with relatively low morbidity and mortality. Anterior clinoidectomy is required only in selected cases, and we prefer the intradural approach during the LSO approach. High-power coagulation should be avoided in proximity of the optic nerve.

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Efficacy of endoport-guided endoscopic resection for deep-seated brain lesions

Neurosurg Rev DOI 10.1007/s10143-011-0319-4

Surgery for deep-seated brain lesions without causing significant trauma to the overlying cortex is difficult because brain retraction is required to approach these lesions.

The aim of this study was to determine the efficacy of endoport-guided endoscopic or microscopic removal for deep-seated lesions using the neuronavigation system.

Between October 2008 and December 2009, 21 patients (17 men and 4 women; average age, 40.8 years) underwent endoport-guided endoscopic tumor removal. We adapted the transparent tubular conduit, so-called “endoport,” to target the lesions under the guidance of neuronavigation. We then determined the efficacy and limitations of this technique with fully endoscopic removal, compared with standard approaches using a spatula retractor.

Gross total resection of the lesions was achieved in 14 of 21 patients (66%), and partial removal occurred in four (19%) patients. However, there was failure to remove the lesion through the endoport in three patients (14.3%), requiring the use of blade spatula retractors. In reviewing the seven cases with either failure or partial removal, it was found that a large tumor size (≥3 cm) and calcified lesions were the major factors limiting the application of this technique.

Endoport-guided endoscopic surgery facilitated an accurate and minimally invasive technique for removal of these deep-seated brain lesions. This procedure required a protracted learning curve although, when successful, this approach can minimize brain retraction and provide satisfactory visualization.

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Middle turbinate vascularized flap for skull base reconstruction after an expanded endonasal approach

Acta Neurochir. DOI 10.1007/s00701-011-1064-8

The expanded endonasal approaches to the skull base are modular approaches that arise from the sphenoidal sinus. The reconstructive techniques in these approaches are key to avoid postoperative complications. Available flaps for reconstruction include the pedicled nasoseptal flap, the transpterygoid temporoparietal fascia flap, and the posterior pedicle inferior turbinate flap (PPITF), among others. Recently, the middle turbinate flap has been described in a cadaveric study. We report our preliminary experience in the use of this middle turbinate vascularized flap for skull base reconstruction after expanded endonasal approaches.

Material and methods Ten patients underwent reconstructive procedures with the mucoperiostial vascularized middle turbinate flap. Capability to cover the defect, closure success, operative time and complications related to the procedure are retrospectively analyzed.

Results A satisfactory closure was obtained in all procedures, and there were no complications related to the technique. Required operative time was similar to the time employed for the nasoseptal flap.

Conclusions The vascularized middle turbinate flap is a reliable reconstructive technique for the reconstruction of moderate-sized skull base defects. It can be considered either as the first choice of closure or as an alternative to the nasoseptal flap when this is not available. Different flap combinations may facilitate skull base defect reconstruction.

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Cotton-Clipping Technique to Repair Intraoperative Aneurysm Neck Tear: A Technical Note

Neurosurgery 68[ONS Suppl 2]:ons294–ons299, 2011 DOI: 10.1227/NEU.0b013e31821343c6

Intraoperative rupture of an intracranial aneurysm is a potentially devastating but avoidable and manageable complication of aneurysm surgery.

OBJECTIVE: To describe a surgical technique that the authors have used successfully to repair a tear at the neck of an intracranial aneurysm, as well as alternative options for managing this intraoperative complication.

METHODS: The tear on the neck of the aneurysm is covered with a small piece of free cotton and held in place with a suction device to clear the field of blood. The cotton is then clipped onto the tear with an aneurysm clip, using the cotton as a bolster to obliterate the tear. The cotton increases the surface area, allowing the clip to be placed more distally on the neck to preserve patency of the parent artery. Case examples are used to illustrate the technique.

RESULTS: Both authors independently have used this technique on several occasions to successfully repair tears at the neck of an aneurysm.

CONCLUSION: Intraoperative rupture of an intracranial aneurysm is a potentially devastating complication, particularly if a tear occurs at the neck. This simple yet effective method has been very useful in repairing a partial avulsion or tear of the neck of an aneurysm.

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Facetal distraction as treatment for single- and multilevel cervical spondylotic radiculopathy and myelopathy

J Neurosurg Spine 14:689–696, 2011. DOI: 10.3171/2011.2.SPINE10601
The authors discuss their successful preliminary experience with 36 cases of cervical spondylotic disease by performing facetal distraction using specially designed Goel cervical facet spacers. The clinical and radiological results of treatment are analyzed. The mechanism of action of the proposed spacers and the rationale for their use are evaluated. Between 2006 and February 2010, 36 patients were treated using the proposed technique. Of these patients, 18 had multilevel and 18 had single-level cervical spondylotic radiculopathy and/or myelopathy. The average follow-up period was 17 months with a minimum of 6 months. The Japanese Orthopaedic Association classification system, visual analog scale (neck pain and radiculopathy), and Odom criteria were used to monitor the clinical status of the patient. The patients were prospectively analyzed. The technique of surgery involved wide opening of the facet joints, denuding of articular cartilage, distraction of facets, and forced impaction of Goel cervical facet spacers into the articular cavity. Additionally, the interspinous process ligaments were resected, and corticocancellous bone graft from the iliac crest was placed and was stabilized over the adjoining laminae and facets after adequately preparing the host bone. Eighteen patients underwent single-level, 6 patients underwent 2-level, and 12 patients underwent 3-level treatment. The alterations in the physical architecture of spine and canal dimensions were evaluated before and after the placement of intrafacet joint spacers and after at least 6 months of follow-up. All patients had varying degrees of relief from symptoms of pain, radiculopathy, and myelopathy. Analysis of radiological features suggested that the distraction of facets with the spacers resulted in an increase in the intervertebral foraminal dimension (mean 2.2 mm), an increase in the height of the intervertebral disc space (range 0.4–1.2 mm), and an increase in the interspinous distance (mean 2.2 mm). The circumferential distraction resulted in reduction in the buckling of the posterior longitudinal ligament and ligamentum flavum. The procedure ultimately resulted in segmental bone fusion. No patient worsened after treatment. There was no noticeable implant malfunction. During the follow-up period, all patients had evidence of segmental bone fusion. No patient underwent reexploration or further surgery of the neck. Distraction of the facets of the cervical vertebra can lead to remarkable and immediate stabilization-fixation of the spinal segment and increase in space for the spinal cord and roots. The procedure results in reversal of several pathological events related to spondylotic disease. The safe, firm, and secure stabilization at the fulcrum of cervical spinal movements provided a ground for segmental spinal arthrodesis. The immediate postoperative improvement and lasting recovery from symptoms suggest the validity of the procedure.

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Intraoperative Confocal Microscopy for Brain Tumors: A Feasibility Analysis in Humans

Neurosurgery 68[ONS Suppl 2]:ons282–ons290, 2011. DOI: 10.1227/NEU.0b013e318212464e

The ability to diagnose brain tumors intraoperatively and identify tumor margins during resection could maximize resection and minimize morbidity. Advances in optical imaging enabled production of a handheld intraoperative confocal microscope.

OBJECTIVE: To present a feasibility analysis of the intraoperative confocal microscope for brain tumor resection.

METHODS: Thirty-three patients with brain tumor treated at Barrow Neurological Institute were examined. All patients received an intravenous bolus of sodium fluorescein before confocal imaging with the Optiscan FIVE 1 system probe. Optical biopsies were obtained within each tumor and along the tumor-brain interfaces. Corresponding pathologic specimens were then excised and processed. These data was compared by a neuropathologist to identify the concordance for tumor histology, grade, and margins.

RESULTS: Thirty-one of 33 lesions were tumors (93.9%) and 2 cases were identified as radiation necrosis (6.1%). Of the former, 25 (80.6%) were intra-axial and 6 (19.4%) were extra-axial. Intra-axial tumors were most commonly gliomas and metastases, while all extra-axial tumors were meningiomas. Among high-grade gliomas, vascular neoproliferation, as well as tumor margins, were identifiable using confocal imaging. Meningothelial and fibrous meningiomas were distinct on confocal microcopy—the latter featured spindle-shaped cells distinguishable from adjacent parenchyma. Other tumor histologies correlated well with standard neuropathology tissue preparations.

CONCLUSION: Intraoperative confocal microscopy is a practicable technology for the resection of human brain tumors. Preliminary analysis demonstrates reliability for a variety of lesions in identifying tumor cells and the tumor-brain interface. Further refinement of this technology depends upon the approval of tumor-specific fluorescent contrast agents for human use.

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How I do it: epidural anterior petrosectomy

Acta Neurochir (2011) 153:1161–1167. DOI 10.1007/s00701-011-1010-9

Among the potential approaches to access the petroclival area, epidural anterior petrosectomy (EAP) appears to be the most direct and conservative transpetrous route.

In this article, we aim to detail the relevant surgical steps necessary to perform EAP in a reproducible and safe manner.

Method The temporo-pterional bone flap is tailored to access the floor of the middle fossa and expose the foramen ovale and foramen spinosum. Elevation of the dura covering the upper surface of the petrous apex is conducted medially toward the level of the petrous ridge. Identification of the landmarks of the rhomboid fossa delineates the limits of the drilling zone (necessary for removal of the petrous apex)—beneath Meckel’s cave and just anterior to the anterior margin of the internal auditory meatus. The tentorium is divided at its free edge and is followed by opening of the posterior fossa dura.

Conclusion Epidural anterior petrosectomy is a conservative trans-petrous approach that offers an excellent direct surgical corridor for exposure of disease processes involving Meckel’s cave, the petroclival area and the ventrolateral pons

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Use of 5-ALA fluorescence guided endoscopic biopsy of a deep-seated primary malignant brain tumor

J Neurosurg 114:1410–1413, 2011. DOI: 10.3171/2010.11.JNS10250

The introduction of fluorescence-guided resection of primary malignant brain tumors was a milestone in neurosurgery. Deep-seated malignant brain tumors are often not approachable for microsurgical resection. For diagnosis and therapy, new strategies are recommended. The combination of endoscopy and 5-aminolevulinic acid–induced protoporphyrin IX (5-ALA-induced Pp IX) fluorescence–guided procedures supported by neuronavigation seems an interesting option. Here the authors report on a combined approach for 5-ALA fluorescence–guided biopsy in which they use an endoscopy system based on an Xe lamp (excitation approximately lambda = 407 nm; dichroic filter system lambda = 380–430 nm) to treat a malignant tumor of the thalamus and perform a ventriculostomy and septostomy. The excitation filter and emission filter are adapted to ensure that the remaining visible blue remission is sufficient to superimpose on or suppress the excited red fluorescence of the endogenous fluorochromes. The authors report that the lesion was easily detectable in the fluorescence mode and that biopsy led to histological diagnosis.

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Robotic Digital Subtraction Angiography Systems Within the Hybrid Operating Room

Neurosurgery 68:1427–1433, 2011 DOI: 10.1227/NEU.0b013e31820b4f1c

Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery.

OBJECTIVE: To describe initial clinical experience with a robotic DSA system in the hybrid OR.

METHODS: A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation.

RESULTS: Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement.

CONCLUSION: This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

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