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Michael A. Murphy, Terence J. O'Brien, Kevin Morris, and Mark J. Cook

epileptogenic focus. This approach has been termed “MMIGS.” The application of image-guided surgery for the treatment of epilepsy has improved our ability to resect lesions causing epilepsy. Currently, it is based on a T 1 -weighted volumetric MR image with high structural resolution and anatomical detail. Note that functional imaging modalities do not have the structural resolution to be used as IGSSs on their own. Image coregistration is applied to integrate the functional imaging data with high-resolution T 1 -weighted images ready for use in the IGSS. The purpose of

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Michael Schulder, Joseph A. Maldjian, Wen-Ching Liu, Andrei I. Holodny, Andrew T. Kalnin, In Ki Mun, and Peter W. Carmel

emission tomography (PET), 12 magnetoencephalography, 7, 13, 30 and functional magnetic resonance (fMR) imaging. 20, 22, 25 In recent years interactive, anatomical image-guided surgery has become available in the form of frameless stereotactic systems. These register a preoperative diagnostic image to surgical space with the aid of devices such as a digitized articulating arm 15 or detectors that track devices emitting ultrasound 5 or infrared light. 33 Thus, the possibility exists for combining noninvasive, preoperative brain mapping with interactive surgical

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Sunil Jeswani, Doniel Drazin, Joseph C. Hsieh, Faris Shweikeh, Eric Friedman, Robert Pashman, J. Patrick Johnson, and Terrence T. Kim

Given the greater probability of error in placing pedicle screws in small thoracic pedicles, we retrospectively examined the accuracy of previous screw placements in patients with small thoracic pedicles that had been performed using intraoperative CT-guided navigation. In the present study, we analyze our experience with pedicle screw placements in thoracic pedicles with diameters ≤ 3 mm. To our knowledge, this is the first study in which the efficacy of CT image–guided surgery (CT-IGS) for placing pedicle screws in such small thoracic pedicles has been exclusively

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Joseph C. Hsieh, Doniel Drazin, Alexander O. Firempong, Robert Pashman, J. Patrick Johnson, and Terrence T. Kim

, particularly computed tomography image–guided surgery (CT-IGS), has emerged as an alternative to fluoroscopy-based techniques. The argument for CT-IGS has been most compelling in cases of brain and spinal cord tumors, trauma, complex deformity (acquired or congenital), obesity, osteoporosis, and revision surgery. In each of these instances, anatomy is significantly altered and difficulties are compounded by limitations in imaging visualization of bony landmarks. This study focuses on evaluating the performance of CT-IGS in the setting of primary versus revision spine surgery

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Harsh Wadhwa, Karen Malacon, Zachary A. Medress, Christopher Leung, Matthew Sklar, and Corinna C. Zygourakis

preoperative assessment, and a computed tomography angiogram (CTA) is often obtained preoperatively to carefully delineate vascular anatomy and provide guidance on safe screw placement. Use of intraoperative fluoroscopy or computer-assisted navigation during surgery may further reduce surgical complication risk and improve screw accuracy. 7 , 8 The Machine-vision Image Guided Surgery (MvIGS) system (7D Surgical, Inc.) is an intraoperative spinal navigation system that uses optical topographic imaging. Unlike other navigation systems that rely on intraoperative fluoroscopy

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Peter A. Woerdeman, Peter W. A. Willems, Herke Jan Noordmans, and Jan Willem Berkelbach van der Sprenkel

In this study the authors measured the effect of auditory feedback during image-guided surgery (IGS) in a phantom model and in a clinical setting. In the phantom setup, advanced IGS with complementary auditory feedback was compared with results obtained with 2 routine forms of IGS, either with an on-screen image display or with imageinjection via a microscope. The effect was measured by means of volumetric resection assessments. The authors also present their first clinical data concerning the effects of complementary auditory feedback on instrument handling during image-guided neurosurgery. When using image-injection through the microscope for navigation, however, resection quality was significantly worse. In the clinical portion of the study, the authors performed resections of cerebral mass lesions in 6 patients with the aid of auditory feedback. Instrument tip speeds were slightly (although significantly) influenced by this feedback during resection. Overall, the participating neurosurgeons reported that the auditory feedback helped in decision-making during resection without negatively influencing instrument use. Postoperative volumetric imaging studies revealed resection rates of ≥ 95% when IGS with auditory feedback was used. There was only a minor amount of brain shift, and postoperative resection volumes corresponded well with the preoperative intentions of the neurosurgeon. Although the results of phantom surgery with auditory feedback revealed no significant effect on resection quality or extent, auditory cues may help prevent damage to eloquent brain structures.

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Ciaran Bolger and Crispin Wigfield

applying intracranial techniques to the spine; however, we believe that the benefits offered by image-guidance systems outweigh the disadvantages, especially when applied to complex spinal cases. It is our belief that image-guided surgery performed in the cervical and thoracic spine has several advantageous applications. The system is useful for preoperative evaluation and surgical planning. For example, in our five cases of C1–2 fixation in which there was a defective pedicle, it was known preoperatively that only a unilateral screw could be accommodated in four cases

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John Y. K. Lee, John T. Pierce, Jayesh P. Thawani, Ryan Zeh, Shuming Nie, Maria Martinez-Lage, and Sunil Singhal

OBJECTIVE

Meningiomas are the most common primary tumor of the central nervous system. Complete resection can be curative, but intraoperative identification of dural tails and tumor remnants poses a clinical challenge. Given data from preclinical studies and previous clinical trials, the authors propose a novel method of localizing tumor tissue and identifying residual disease at the margins via preoperative systemic injection of a near-infrared (NIR) fluorescent contrast dye. This technique, what the authors call “second-window indocyanine green” (ICG), relies on the visualization of ICG approximately 24 hours after intravenous injection.

METHODS

Eighteen patients were prospectively identified and received 5 mg/kg of second-window ICG the day prior to surgery. An NIR camera was used to localize the tumor prior to resection and to inspect the margins following standard resection. The signal to background ratio (SBR) of the tumor to the normal brain parenchyma was measured in triplicate. Gross tumor and margin specimens were qualitatively reported with respect to fluorescence. Neuropathological diagnosis served as the reference gold standard to calculate the sensitivity and specificity of the imaging technique.

RESULTS

Eighteen patients harbored 15 WHO Grade I and 3 WHO Grade II meningiomas. Near-infrared visualization during surgery ranged from 18 to 28 hours (mean 23 hours) following second-window ICG infusion. Fourteen of the 18 tumors demonstrated a markedly elevated SBR of 5.6 ± 1.7 as compared with adjacent brain parenchyma. Four of the 18 patients showed an inverse pattern of NIR signal, that is, stronger in the adjacent normal brain than in the tumor (SBR 0.31 ± 0.1). The best predictor of inversion was time from injection, as the patients who were imaged earlier were more likely to demonstrate an appropriate SBR. The second-window ICG technique demonstrated a sensitivity of 96.4%, specificity of 38.9%, positive predictive value of 71.1%, and a negative predictive value of 87.5% for tumor.

CONCLUSIONS

Systemic injection of NIR second-window ICG the day before surgery can be used to visualize meningiomas intraoperatively. Intraoperative NIR imaging provides higher sensitivity in identifying meningiomas than the unassisted eye. In this study, 14 of the 18 patients with meningioma demonstrated a strong SBR compared with adjacent brain. In the future, reducing the time interval from dye injection to intraoperative imaging may improve fluorescence at the margins, though this approach requires further investigation.

Clinical trial registration no.: NCT02280954 (clincialtrials.gov).

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Sandra L. Poliachik, Andrew V. Poliakov, Laura A. Jansen, Sharon S. McDaniel, Carter D. Wray, John Kuratani, Russell P. Saneto, Jeffrey G. Ojemann, and Edward J. Novotny Jr

M ore than 50 million people worldwide have epilepsy. Approximately 25%–35% of these individuals do not respond to antiepileptic medication or dietary interventions and should be evaluated for possible epilepsy surgery. Imaging is an integral part of the comprehensive preoperative evaluation for epilepsy, supporting identification of a specific part of the brain as the epileptic focus (for example, structural or metabolic abnormality). Imaging-guided surgery systems are now widely used in surgical practice, especially in neurosurgery. 4 , 15 Navigation

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Asgeir S. Jakola, Geirmund Unsgård, and Ole Solheim

Object

Outcome following brain tumor operations is often assessed by health professionals using various gross function scales. However, surprisingly little is known about how modern glioma surgery affects quality of life (QOL) as reported by the patients themselves. In the present study the authors aimed to assess changes in QOL after glioma surgery, to explore the relationship between QOL and traditional outcome parameters, and to examine possible predictors of change in QOL.

Methods

Eighty-eight patients with glioma were recruited from among those 16 years or older who had been admitted to the authors' department for brain tumor surgery in the period between January 2007 and December 2009. A 3D ultrasonography–based navigation system was utilized in nearly all operations and functional MR imaging data on eloquent lesions were incorporated into the neuronavigation system. Preoperative scores for QOL (EuroQol 5D [EQ-5D]) and functional status (Karnofsky Performance Scale [KPS]) were obtained. The EQ-5D and KPS scores were subsequently recorded 6 weeks postoperatively, as were responses to a structured interview about new deficits and possible complications.

Results

There was no change in the median EQ-5D indexes following surgery, 0.76 versus 0.75 (p = 0.419). The EQ-5D index value was significantly correlated with the KPS score (p < 0.001; rho = 0.769). The EQ-5D index values and KPS scores improved in 35.2% and 24.1% of cases, were equal in 20.5% and 47.2% of cases, and deteriorated in 44.3% and 28.7%, respectively. Thus, both improvement and deterioration were underestimated by the KPS score as compared with the patient-reported QOL assessment. New motor deficits (p = 0.003), new language deficits (p = 0.035), new unsteadiness and/or ataxia (p = 0.001), occipital lesions (p = 0.019), and no use of ultrasonography for resection control (p = 0.021) were independent predictors of worsening QOL in a multivariate model.

Conclusions

The surgical procedures per se may not significantly alter QOL in the average patient with glioma; however, new deficits have a major undesirable effect on QOL. It seems that the active use of intraoperative ultrasonography may be associated with a preservation of QOL. The EQ-5D seems like a good outcome measure with a strong correlation to traditional variables while offering a more detailed description of outcome.