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At least 757 records · Page 42Linked to original sources
PubMed2005

Independent predictors of morbidity after image-guided stereotactic brain biopsy: a risk assessment of 270 cases.

OBJECT: Image-guided stereotactic brain biopsy is associated with transient and permanent incidences of morbidity in 9 and 4.5% of patients, respectively. The goal of this study was to perform a critical analysis of risk factors predictive of an enhanced operative risk in frame-based and frameless stereotactic brain biopsy. METHODS: The authors reviewed the clinical and neuroimaging records of 270 patients who underwent consecutive frame-based and frameless image-guided stereotactic brain biopsies. The association between preoperative variables and biopsy-related morbidity was assessed by performing a multivariate logistic regression analysis. Transient and permanent stereotactic biopsy-related morbidity was observed in 23 (9%) and 13 (5%) patients, respectively. A hematoma occurred at the biopsy site in 25 patients (9%); 10 patients (4%) were symptomatic. Diabetes mellitus (odds ratio [OR] 3.73, 95% confidence interval [CI] 1.37-10.17, p = 0.01), thalamic lesions (OR 4.06, 95% CI 1.63-10.11, p = 0.002), and basal ganglia lesions (OR 3.29, 95% CI 1.05-10.25, p = 0.04) were in'dependent risk factors for morbidity. In diabetic patients, a serum level of glucose that was greater than 200 mg/dl on the day of biopsy had a 100% positive predictive value and a glucose level lower than 200 mg/dl on the same day had a 95% negative predictive value for biopsy-related morbidity. Pontine biopsy was not a risk factor for morbidity. Only two (4%) of 45 patients who had epilepsy before the biopsy experienced seizures postoperatively. The creation of more than one needle trajectory increased the incidence of neurological deficits from 17 to 44% when associated with the treatment of deep lesions (those in the basal ganglia or thalamus; p = 0.05), but was not associated with morbidity when associated with the treatment of cortex lesions. CONCLUSIONS: Basal ganglia lesions, thalamic lesions, and patients with diabetes were independent risk factors for biopsy-associated morbidity. Hyperglycemia on the day of biopsy predicted morbidity in the diabetic population. Epilepsy did not predispose to biopsy-associated seizure. For deep-seated lesions, increasing the number of biopsy samples along an established track rather than performing a second trajectory may minimize the incidence of morbidity. Close perioperative observation of glucose levels may be warranted.

Basal Ganglia Diseases↗
PubMed2005

Frameless stereotactic placement of depth electrodes in epilepsy surgery.

OBJECT: Depth electrodes are useful in the identification of deep epileptogenic foci. Computerized tomography-magnetic resonance (CT/MR)- and angiography-guided frame-based techniques are safe and accurate but require four-point skull fixation that limits cranial access for the placement of additional grids and strips. The authors investigated the viability and accuracy of placing depth electrodes by using a commercially available frameless system. METHODS: A slotted, custom-designed adapter was built to interface with the StealthStation Guide Frame-DT and 960-525 StealthFighter. The Cranial Navigation software was used to plan the trajectory and entry site based on preoperative spoiled gradient MR imaging studies. Forty-one depth electrodes were placed in 51 targets in 20 patients. Thirty-one of these electrodes were inserted through the temporal neocortex following craniotomy and placement of subdural grids, whereas 10 were placed through burr holes. All electrodes had contact either within (71%) or touching (29%) the target, 50 of which (98%) provided adequate recordings. Although the mean distance of the distal electrode contact from the intended target was 3.1 +/- 0.5 mm, the mean distance to the edge of the anatomical structure was 0.4 +/- 0.9 mm. Placement via the laterotemporal approach was significantly (p < 0.001) more accurate than that via the occipitotemporal approach. No complication occurred. CONCLUSIONS: Depth electrodes can be placed safely and accurately by using a commercially available frameless stereotactic navigation system and a custom-made adapter. Depth electrode placement to record ictal onsets during epilepsy surgery only requires the contacts to touch rather than to reside within the intended structure. The laterotemporal approach is a more accurate method of placing electrodes than is the occipitotemporal one, likely due to the increased distance from the entry point to the target.

Adolescent↗
PubMed2006

Frameless image-guided stereotactic brain biopsy procedure: diagnostic yield, surgical morbidity, and comparison with the frame-based technique.

OBJECT: The gold standard for stereotactic brain biopsy target localization has been frame-based stereotaxy. Recently, frameless stereotactic techniques have become increasingly utilized. Few authors have evaluated this procedure, analyzed preoperative predictors of diagnostic yield, or explored the differences in diagnostic yield and morbidity rate between the frameless and frame-based techniques. METHODS: A consecutive series of 110 frameless and 160 frame-based image-guided stereotactic biopsy procedures was reviewed. Associated variables for both techniques were reviewed and compared. All stereotactic biopsy procedures were included in a risk factor analysis of nondiagnostic biopsy sampling. Frameless stereotaxy led to a diagnostic yield of 89%, with a total permanent morbidity rate of 6% and a mortality rate of 1%. Larger lesions were fivefold more likely to yield diagnostic tissues. Deep-seated lesions were 2.7-fold less likely to yield diagnostic tissues compared with cortical lesions. Frameless compared with frame-based stereotactic biopsy procedures showed no significant differences in diagnostic yield or transient or permanent morbidity. For cortical lesions, more than one needle trajectory was required more frequently to obtain diagnostic tissues with frame-based as opposed to frameless stereotaxy, although this factor was not associated with morbidity. CONCLUSIONS: With regard to diagnostic yield and complication rate, the frameless stereotactic biopsy procedure was found to be comparable to or better than the frame-based method. Smaller and deep-seated lesions together were risk factors for a nondiagnostic tissue yield. Frameless stereotaxy may represent a more efficient means of obtaining biopsy specimens of cortical lesions but is otherwise similar to the frame-based technique.

Adult↗
PubMed2006

Integrated positron emission tomography and magnetic resonance imaging-guided resection of brain tumors: a report of 103 consecutive procedures.

OBJECT: The aim of this study was to evaluate the integration of positron emission tomography (PET) scanning data into the image-guided resection of brain tumors. METHODS: Positron emission tomography scans obtained using fluorine-18 fluorodeoxyglucose (FDG) and L-[methyl-11C]methionine (MET) were combined with magnetic resonance (MR) images in the navigational planning of 103 resections of brain tumors (63 low-grade gliomas [LGGs] and 40 high-grade gliomas [HGGs]). These procedures were performed in 91 patients (57 males and 34 females) in whom tumor boundaries could not be accurately identified on MR images for navigation-based resection. The level and distribution of PET tracer uptake in the tumor were analyzed to define the lesion contours, which in turn yielded a PET volume. The PET scanning-demonstrated lesion volume was subsequently projected onto MR images and compared with MR imaging data (MR volume) to define a final target volume for navigation-based resection-the tumor contours were displayed in the microscope's eyepiece. Maximal tumor resection was accomplished in each case, with the intention of removing the entire area of abnormal metabolic activity visualized during surgical planning. Early postoperative MR imaging and PET scanning studies were performed to assess the quality of tumor resection. Both pre- and postoperative analyses of MR and PET images revealed whether integrating PET data into the navigational planning contributed to improved tumor volume definition and tumor resection. Metabolic information on tumor heterogeneity or extent was useful in planning the surgery. In 83 (80%) of 103 procedures, PET studies contributed to defining a final target volume different from that obtained with MR imaging alone. Furthermore, FDG-PET scanning, which was performed in a majority of HGG cases, showed that PET volume was less extended than the MR volume in 16 of 21 cases and contributed to targeting the resection to the hypermetabolic (anaplastic) area in 11 (69%) of 16 cases. Performed in 59 LGG cases and 23 HGG cases, MET-PET demonstrated that the PET volume did not match the MR volume and improved the tumor volume definition in 52 (88%) of 59 and 18 (78%) of 23, respectively. Total resection of the area of increased PET tracer uptake was achieved in 54 (52%) of 103 procedures. CONCLUSIONS: Imaging guidance with PET scanning provided independent and complementary information that helped to assess tumor extent and plan tumor resection better than with MR imaging guidance alone. The PET scanning guidance could help increase the amount of tumor removed and target image-guided resection to tumor portions that represent the highest evolving potential.

Adolescent↗
PubMed2006

Efficacy of and morbidity associated with stereoelectroencephalography using computerized tomography--or magnetic resonance imaging-guided electrode implantation.

OBJECT: The purpose of this paper was to define the general efficacy of and morbidity associated with stereoelectroencephalography using modem methods of imaging and to particularize the risks related to specific lobes of the brain. METHODS: All patients admitted to the Montreal Neurological Institute who had undergone either computerized tomography- or magnetic resonance imaging-guided electrode implantation by one surgeon (A.O.) were reviewed. The procedure was considered efficient if the obtained information was sufficient to make a decision either in support of or against surgery. Two hundred seventeen patients underwent 224 implantations with 3022 electrodes. Complications related to each lobe were as follows: temporal lobe, two abscesses (0.54%); frontal lobe, one abscess and three hematomas (1.4%); and occipital lobe, one hypointense lesion found 1 week after electrode explantation (2.6%). Significant risk factors associated with hematomas were implantation in the frontal lobe (p < 0.05) and the use of four or more implanted electrodes (p < 0.025). General complications included the following: 26 patients, psychiatric symptoms during monitoring; one patient, meningitis; four patients, scalp cellulitis; and two patients, hemiparesis during angiography in the early 1980s. One of these latter patients maintained a mild hemiparesis and represents the only case of permanent neurological sequela in the entire series. Data obtained during recordings supported an indication for surgery in 178 patients (79.5%), excluded a surgical option in 37 patients (16.5%), and were unsatisfactory in nine patients (4%). Thus, the overall efficacy as defined previously was 96%. CONCLUSIONS: Stereoelectroencephalography is an efficient procedure with low associated morbidity. Bilateral exploration of the temporal lobes has a morbidity rate of approximately 1%. A higher risk of hematomas occurs with the implantation of four or more electrodes in the frontal lobes.

Adult↗
PubMed2006

Microelectrode-guided implantation of deep brain stimulators into the globus pallidus internus for dystonia: techniques, electrode locations, and outcomes.

OBJECT: Deep brain stimulation (DBS) of the globus pallidus internus (GPI) is a promising new procedure for the treatment of dystonia. The authors describe their technical approach for placing electrodes into the GPI in awake patients with dystonia, including methodology for electrophysiological mapping of the GPI in the dystonic state, clinical outcomes and complications, and the location of electrodes associated with optimal benefit. METHODS: Twenty-three adult and pediatric patients with various forms of dystonia were included in this study. Baseline neurological status and DBS-related improvement in motor function were measured using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). The implantation of DBS leads was performed using magnetic resonance (MR) imaging-based stereotaxy, single-cell microelectrode recording, and intraoperative test stimulation to determine thresholds for stimulation-induced adverse effects. Electrode locations were measured on computationally reformatted postoperative MR images according to a prospective protocol. CONCLUSIONS: Physiologically guided implantation of DBS electrodes in patients with dystonia was technically feasible in the awake state in most patients, and the morbidity rate was low. Spontaneous discharge rates of GPI neurons in dystonia were similar to those of globus pallidus externus neurons, such that the two nuclei must be distinguished by neuronal discharge patterns rather than rates. Active electrode locations associated with robust improvement (> 70% decrease in BFMDRS score) were located near the intercommissural plane, at a mean distance from the pallidocapsular border of 3.6 mm.

Adolescent↗
PubMed2006

Preoperative endovascular brain mapping for intraoperative volumetric image guidance: preliminary concept and feasibility in animal models.

OBJECT: The authors describe a novel concept for brain mapping in which an endovascular approach is used, and they demonstrate its feasibility in animal models. The purpose of endovascular brain mapping is to delineate clearly the nonfunctional brain parenchyma when a craniotomy is performed for resection. The nonfunctional brain will be stained with sharp visual margins, differentiating it from the functional, nonstained brain. The authors list four essential criteria for developing an ideal endovascular mapping agent, and they describe seven potential approaches for accomplishing a successful endovascular brain map. METHODS: Four Sprague-Dawley rats and one New Zealand white rabbit were used to determine initial feasibility of the procedure. The animals were anesthetized, and the internal carotid artery was catheterized. Four potential brain mapping agents were infused into the right hemisphere of the five animals. Afterward, the brains were removed and each was analyzed both grossly and histologically. Fluorescein and FD&C Green No. 3 provided good visual clarity and margins, but required blood-brain barrier (BBB) manipulation. Tantalum particles enabled avoidance of BBB manipulation, but provided inadequate visual clarity, probably because of their size. A Sudan black "cocktail" provided excellent clarity and margins despite remaining in the brain capillaries. CONCLUSIONS: This is a novel application of the endovascular approach, and has broad potential for clinical neurosurgical brain mapping. The animal models in this study establish the feasibility of the procedure. However, further study is required to demonstrate safety, minimize toxicity, investigate stain durability, and improve the characteristics of potential mapping agents. The authors are planning to conduct future studies for identification of mapping agents that do not require BBB manipulation or vascular occlusion.

Angiography, Digital Subtraction↗
PubMed2006

Cranial surgery with an expanded compact intraoperative magnetic resonance imager. Technical note.

In this article the authors report the implementation of an expanded compact intraoperative magnetic resonance (iMR) imager that is designed to overcome significant limitations of an earlier unit. The PoleStar N20 iMR imager has a stronger magnetic field than its predecessor (0.15 tesla compared with 0.12 tesla), a wider gap between magnet poles, and an ergonomically improved gantry design. The additional time needed in the operating room (OR) for use of iMR imaging and the number of sessions per patient were recorded. Stereotactic accuracy of the integrated navigational tool was assessed using a water-covered phantom. Of the 55 patients who have undergone surgery in the PoleStar N20 device, diagnoses included glioma in 13, meningioma in 12, pituitary adenoma in nine, other skull base lesions in seven, and miscellaneous other diagnoses. The extra time required for use of the system averaged 1.1 hours (range 0.5-2 hours). Imaging sessions averaged 2.3 per surgery (range one-six sessions). Measurement of stereotactic accuracy revealed that T1-weighted images were the most accurate. Thinner slices yielded measurably greater accuracy, although this was of questionable clinical significance (all sequences < or =4 mm had a mean error of < or = 1.8 mm). The position of the phantom in the center compared with the periphery of the magnetic field did not affect accuracy (mean error 0.9 mm for each). The PoleStar N20 appears to make intraoperative neuroimaging with a low-field-strength magnet much more practical than it was with the first-generation device. Greater ease of positioning resulted in a decrease in added time in the OR and encouraged a larger number of imaging sessions.

Adult↗
PubMed2006

Three-dimensional rotational angiography guidance for aneurysm surgery.

OBJECT: The aim of this study was to investigate the feasibility of integrating three-dimensional rotational angiography (3D-RA) data into a surgical navigation system and to assess its accuracy and potential clinical benefit. METHODS: The study cohort consisted of 16 patients with 16 intracranial aneurysms who had been scheduled for routine or emergency surgery. Rotational angiography data were exported using a virtual reality modeling language file format and imported into the BrainLAB VectorVision2 image-guided surgery equipment. During 3D-RA the position of the head was measured using a special headframe. The authors also determined the accuracy of 3D-RA image guidance and the clinical benefit as judged by the surgeon, including, for example, early identification of branching vessels and the aneurysm. There was good correspondence between the 3D-RA-based navigation data and the intraoperative vascular anatomy in all cases, with a maximum error of 9 degrees of angulation and 9 degrees of rotation. In eight cases, the surgeon determined that the 3D-RA image guidance facilitated the surgical procedure by predicting the location of the aneurysm or the origin of a branching artery that had been covered by brain tissue and blood clots. CONCLUSIONS: The integration of 3D-RA into surgical navigation systems is feasible, but it currently requires a new perspective-registration technique. The intraoperative 3D view provides useful information about the vascular anatomy and may improve the quality of aneurysm surgery in selected cases.

Adult↗
PubMed2006

In vivo accuracy of image guidance performed using optical tracking and optimized registration.

OBJECT: Image guidance systems involving the use of frameless referencing of surgical space to compile volumetric imaging data sets recently have come into widespread use. Few studies have addressed the true intraoperative surgical accuracy (that is, the application accuracy) of these systems except in a subjective manner. Calculated accuracies given by the systems do not necessarily reflect true intraoperative accuracy. METHODS: To objectively assess the stereotactic accuracy of a frameless image guidance system using optical spatial referencing, the author analyzed postoperative magnetic resonance (MR) images after placement of depth electrodes for the investigation of epilepsy. Preoperative planning for the treatment of seven patients included implanting skull fiducial screws and obtaining computed tomography/MR fusion images by using ImMerge image fusion software on the StealthStation (Medtronic, Inc.). A total of 42 electrodes were placed. Postoperative volumetric MR images were fused with preoperative study images. The difference between the planned electrode trajectories and targets and the visualized electrodes was measured in stereotactic space. CONCLUSIONS: The mean distance between the distal electrode contact and the distal end of the planned trajectory for the 42 targets was 3 +/- 1.5 mm. The most common error was in depth. The author's technique did not involve rigid skull fixation of electrodes because they were subsequently tunneled subcutaneously and later removed at the bedside of the patient. Errors in depth were known to be due to traction at the time of tunneling and not due to stereotactic factors. Correcting for depth along the electrode trajectory, the mean accuracy was found to be 2.4 +/- 1 mm.

Electrodes, Implanted↗
PubMed2005

Neuroendoscopic transventricular ventriculocystostomy in treatment for intracranial cysts.

OBJECT: Although in recent years endoscopic procedures have been used for intracranial arachnoid cysts with favorable preliminary results in certain locations, optimal surgical treatment is still controversial. The purpose of this study was to evaluate the efficacy and safety of endoscopic transventricular ventriculocystostomy in the treatment of intracranial cysts based on the concept of normalizing cerebrospinal fluid (CSF) dynamics. METHODS: Twelve symptomatic pediatric patients with congenital intracranial cysts underwent surgery at Jikei University in Tokyo. A neuroendoscopic transventricular ventriculocystostomy was performed in nine patients and an endoscope-assisted craniotomy in the remaining three. Endoscopy was performed using a freehand maneuver with a newly designed rigid-rod neuroendoscope that is frameless and has a small diameter. Clinical results were good in all patients, although cysts in three were not prominently reduced in size when follow-up imaging studies were performed. Neither death nor symptomatic morbidity occurred, and no patient required shunt placement. In three cases the endoscopic fenestration was associated with an endoscopic third ventriculostomy (ETV). Postoperative CSF dynamics studies consisting of computerized tomography ventriculocysternography, and pre- and postoperative cine-mode magnetic resonance imaging demonstrated free communication between fenestrated cysts and ventricular/ cistern CSF pathways consistent with normalization of CSF dynamics. CONCLUSIONS: Neuroendoscopic transventricular ventriculocystostomy constitutes a valid alternative to microsurgery for intracranial cysts located within or adjacent to the ventricles. It creates an effective CSF flow within the cyst with minimal alteration of subarachnoid spaces. It may be combined with an ETV procedure in case of obstruction of CSF pathways and should be preferred to the insertion of shunts.

Adolescent↗
PubMed2005

Topacheous gout as a rare cause of spinal stenosis in the lumbar region. Case report.

Despite the fact that gout is a common metabolic disorder, because its involvement of the axial skeleton is rare the diagnosis is often delayed, even in patients with long-standing gout who present with neurological deficits. The authors report the case of a woman with a history of extensive gout, emphasizing the clinical, radiological, and pathological features of a lumbar spinal stenosis.

Biopsy↗
PubMed2006

Evaluation of registration techniques for spinal image guidance.

OBJECT: Paired point matching alone and paired point matching combined with surface matching are the two techniques used for the registration step in preoperative computerized tomography-based spinal image guidance. In the present study the authors sought to compare paired point-matching registration alone with paired point matching supplemented with surface matching to determine if the addition of surface matching improves navigational accuracy. METHODS: Pedicle screws were placed in three embalmed human cervicothoracic spinal specimens during image guidance to serve as a reference points. The specimens were then rescanned, and each level was registered using paired point matching alone and then by paired point supplemented with surface matching. Navigational accuracy was assessed by placing the stereotactic probe in the center of the screw head, and measuring the apparent distance between the screw head and probe on the computer monitor. Statistical analysis was used to compare the registration error and navigational error between the two techniques. Seventy-five screws were placed at 46 vertebral levels. The mean registration error for the paired point matching/surface matching technique (0.5 mm) was significantly lower (p < 0.001) than that of the paired point matching alone technique (1.2 mm); however, the intertechnique difference in navigational error was nearly equivalent (1.3 mm compared with 1.4 mm) and statistically insignificant (p > 0.05). CONCLUSIONS: Although the addition of surface matching to paired point registration significantly decreased the mean registration error, the actual navigational accuracy between the two techniques was equivalent when easily distinguishable points were meticulously selected. The use of paired point matching alone did not compromise the accuracy of navigation and is likely to result in decreased operating time.

Bone Screws↗
PubMed2006

Technical description, phantom accuracy, and clinical feasibility for fiducial-free frameless real-time image-guided spinal radiosurgery.

OBJECT: The authors describe the technical application of the Xsight Spine Tracking System, data pertaining to accuracy obtained during phantom testing, and the initial clinical feasibility of using this fiducial-free alignment system with the CyberKnife in spinal radiosurgery. METHODS: The Xsight integrates with the CyberKnife radiosurgery system to eliminate the need for implantation of radiographic markers or fiducials prior to spinal radiosurgery. It locates and tracks spinal lesions relative to spinal osseous landmarks. The authors performed 10 end-to-end tests of accuracy using an anthropomorphic head and cervical spine phantom. Xsight was also used in the treatment of 50 spinal lesions in 42 patients. Dose planning was based on 1.5-mm-thick computed tomography slices in which an inverse treatment planning technique was used. All lesions could be treated using the fiducial-free tracking procedure. Phantom tests produced an overall mean targeting error of 0.52 +/- 0.22 mm. The setup time for patient alignment averaged 6 minutes (range 2-45 minutes). The treatment doses varied from 12 to 25 Gy to the median prescription isodose of 65% (40 to 70%). The tumor volume ranged between 1.3 and 152.8 cm3. The mean spinal cord volume receiving greater than 8 Gy was 0.69 +/- 0.35 cm3. No short-term adverse events were noted during the 1- to 7-month follow-up period. Axial and radicular pain was relieved in 14 of 15 patients treated for pain. CONCLUSIONS: Fiducial-free tracking is a feasible, accurate, and reliable tool for radiosurgery of the entire spine. By eliminating the need for fiducial implantation, the Xsight system offers patients noninvasive radiosurgical intervention for intra- and paraspinal tumors.

Adolescent↗
PubMed2005

[Endoscopic endonasal sinus surgery using a navigation system for pituitary adenoma].

Hardy's operation using a microscope has long been the standard for treating pituitary adenoma. A new endonasal approach to the sella using an endoscope combined with a navigation system has been reported, which we used to conduct endocopic endonasal hypophysectomy from October 2000 to June 2003 in 11 patients with pituitary lesions. We introduced an angle-dependent navigation system, Neuro Navigator III. We approached the sphenoid sinus mainly via the hemilateral common meatus. The deviation of the nasal septum and sphenoidal septum was carefully evaluated to determine the optimal operating side. We concluded that the hemilateral common meatus route is useful because it is least invasive in endocopic endonasal hypophysectomy. Another route should be taken, however, if hemorrhaging is uncontrollable or the tumor is quite large. Navigation systems are quite effective in executing this operation safely. Angle-dependent navigation system is a good choice for this operation, considering its cost performance.

Adenoma↗
PubMed2005

[Image-guided endoscopic sinus surgery: a comparison of two navigation systems].

We evaluated the effectiveness of two navigation systems with optical tracking in endoscopic sinus surgery (ESS). The Signa SP/i Intraoperative navigation system (General Electric Co., Intraoperative NS) is advantageous in acquiring both real time and high-resolution images during surgery, compared to conventional image-guided navigation (Stealth Station TREON, Medtronic Inc., IGNS) that rely entirely on preoperative three-dimensional images. We studied the following in 14 patients treated with intraoperative NS and 19 treated with IGNS: 1) additional time for navigation system implementation, 2) available instrumentations in ESS, and 3) navigation system accuracy. Navigation systems required additional time to prepare ESS. The time lapse from admittance to the operating room to ESS onset was measured in patients under both systems and controls undergoing ESS without any image guidance. Preparation of the intraoperative NS required an additional 52 min and IGNS required 17 min compared to the control group. Based on operative instruments, the intraoperative NS has some limitations arising from the application of a high magnetic field. Surgical instruments must not be attracted by the magnetic field in the operating room. So those used in our study were thoroughly examined and some remanufactured using MR safe materials. All instruments in ESS could be used in surgical guidance during surgery in the IGNS. Anatomic landmarks were accurately visualized using intraoperative NS and IGNS. Intraoperative NS renews the image during surgery, so surgeons could confirm the surgical outcome during ESS. Since the average distant error in both systems was between 1 mm and 2.5 mm, we confirmed that accuracy obtained with both navigation system was suitable for ESS completion. The intraoperative NS renewed the image during navigation. In conclusion, both navigation systems are sufficient for accurate image navigation in ESS, but navigation systems must be selected based on the individual case.

Endoscopy↗