Cerebral biopsy: comparison between frame-based stereotaxy and neuronavigation in an oncology center

Clinical outcomes as a function of the number of samples taken during stereotactic needle biopsies: a meta-analysis

BACKGROUND

Stereotactic needle biopsy remains the cornerstone for tissue diagnosis for tumors located in regions of the brain that are difficult to access through open surgery.

OBJECTIVE

We perform a meta-analysis of the literature to examine the relation between number of samples taken during biopsy and diagnostic yield, morbidity and mortality.

METHODS

We identified 2416 patients from 28 cohorts in studies published in PubMed database that studied stereotactic needle biopsies for tumor indications. Meta-analysis by proportions and meta-regression analyses were performed.

RESULTS

On meta-analysis, the morbidity profile of the published needle biopsy studies clustered into three groups: studies that performed < 3 samples (n = 8), 3-6 samples (n = 13), and > 6 samples during biopsy (n = 7). Pooled estimates for biopsy related morbidity were 4.3%, 16.3%, and 17% for studies reporting < 3, 3-6, and > 6 biopsy samples, respectively. While these morbidity estimates significantly differed (p < 0.001), the diagnostic yields reported for studies performing < 3 biopsies, 3-6 samples, and > 6 samples were comparable. Pooled estimates of diagnostic yield for these three groups were 90.4%, 93.8%, and 88.1%, respectively. Mortality did not significantly differ between studies reporting differing number of samples taken during biopsy.

CONCLUSIONS

Our meta-analysis suggests that morbidity risk in needle biopsy is non-linearly associated with the number of samples taken. There was no association between the number of biopsies taken, and diagnostic yield or mortality.

Frameless stereotaxy: It is all about precision

BACKGROUND

Modern neurosurgery is nowadays based on technological advances. Intra-operative image guidance systems are frequently utilized in the everyday neurosurgical practice. Frameless stereotactic procedures (FSPs) require a great deal of technical abilities and precautions. Frameless stereotaxy mandates a high degree of problem-solving attitude and on-the-spot neurosurgeon's creativity.

OBJECTIVE

In these technical notes, the author aims at presenting his experience in frameless stereotaxy for more than 10 years in the form of easily digestible tricks and pitfalls during every step of FSPs.

METHODS

The author retrospectively distilled the tricks and pitfalls of the FSPs performed by him during the past 10 years according to their chronological status in a how-I-do-it fashion.

RESULTS

Chronologically speaking, phases relating to any FSP were divided into five phases: (1) preoperative image acquisition, (2) pre-operative planning, (3) machine setup, positioning, and registration; (4) operative techniques; and (5) post-operative precautions. Faults in any of these phases can result in failure of the procedure or in faulty surgery with subsequent complications. Each stage is addressed in a how I do it fashion, questions and answers, bulleted or numbered tricks and pitfalls, and, in some instances, what-to-do-if scenarios were given.

CONCLUSION

Frameless stereotaxy is a well-established neurosurgical practice. Many neurosurgeons are only aware with the bare minimum of the technical aspects of frameless stereotaxy and, subsequently, they practice the bare minimum of its applications. FSPs entail a great deal of technical tricks and pitfalls. Awareness of these techniques should be the target of every neurosurgeon.

Real-time MR-guided brain biopsy using 1.0-T open MRI scanner

OBJECTIVES

To evaluate the safety, feasibility and diagnostic performance of real-time MR-guided brain biopsy using a 1.0-T open MRI scanner.

METHODS

Medical records of 86 consecutive participants who underwent brain biopsy under the guidance of a 1.0-T open MRI scanner with real-time and MR fluoroscopy techniques were evaluated retrospectively. All procedures were performed under local anaesthesia and intravenous conscious sedation. Diagnostic yield, diagnostic accuracy, complication rate and procedure duration were assessed. The lesions were divided into two groups according to maximum diameters: ≤ 1.5 cm (n = 16) and > 1.5 cm (n = 70). The two groups were compared using Fisher's exact test.

RESULTS

Diagnostic yield and diagnostic accuracy were 95.3% and 94.2%, respectively. The diagnostic yield of lesions ≤ 1.5 cm and > 1.5 cm were 93.8% and 95.7%, respectively. There was no significant difference in diagnostic yield between the two groups (p > 0.05). Mean procedure duration was 41 ± 5 min (range 33-49 min). All biopsy needles were placed with one pass. Complication rate was 3.5% (3/86). Minor complications included three cases of a small amount of haemorrhage. No serious complications were observed.

CONCLUSIONS

Real-time MR-guided brain biopsy using a 1.0-T open MRI scanner is a safe, feasible and accurate diagnostic technique for pathological diagnosis of brain lesions. The procedure duration is shortened and biopsy work flow is simplified. It could be considered as an alternative for brain biopsy.

KEY POINTS

• Real-time MRI-guided brain biopsy using a 1.0-T open MRI scanner is safe, feasible and accurate. • No serious complications occurred in real-time MRI-guided brain biopsy. • Procedure duration is shortened and biopsy work flow is simplified.

Target location after deep cerebral biopsies using low-volume air injection in 75 patients. Results and technical note

BACKGROUND

Stereotactic biopsy is a minimally invasive technique that allows brain tissue samples to be obtained with low risk. Classically, different techniques have been used to identify the biopsy site after surgery.

OBJECTIVE

To describe a technique to identify the precise location of the target in the postoperative CT scan using the injection of a low volume of air into the biopsy cannula.

METHODS

Seventy-five biopsies were performed in 65 adults and 10 children (40 males and 35 females, median age 51 years). Frame-based biopsy was performed in 46 patients, while frameless biopsy was performed in the remaining 29 patients. In both systems, after brain specimens had been collected and with the biopsy needle tip in the center of the target, a small volume of air (median 0.7 cm³) was injected into the site.

RESULTS

A follow-up CT scan was performed in all patients. Intracranial air in the selected target was present in 69 patients (92%). No air was observed in two patients (air volume administered in these 2 cases was below 0.7 cm³), while in the remaining four patients blood content was observed in the target. The diagnostic yield in this series was 97.3%. No complications were found to be associated with intracranial air injection in any of the 75 patients who underwent this procedure.

CONCLUSIONS

The air-injection maneuver proposed for use in stereotactic biopsies of intracranial mass lesions is a safe and reliable technique that allows the exact biopsy site to be located without any related complications.

Accuracy of VarioGuide Frameless Stereotactic System Against Frame-Based Stereotaxy: Prospective, Randomized, Single-Center Study

INTRODUCTION

Frameless stereotactic brain biopsy systems are widely used today. VarioGuide (VG) is a relatively novel frameless system. Its accuracy was studied in a laboratory setting but has not yet been studied in the clinical setting. The purpose of this study was to determine its accuracy and diagnostic yield and to compare this with frame-based (FB) stereotaxy.

MATERIAL AND METHODS

Overall, 53 patients (33 males and 20 females, 60 ± 15 years old) were enrolled into this prospective, randomized, single-center study. Twenty-six patients were randomized into the FB group and 27 patients into the VG group. Real trajectory was pointed on intraoperative magnetic resonance. The distance of the targets and angle deviation between the planned and real trajectories were computed. The overall discomfort of the patient was subjectively assessed by the visual analog scale score.

RESULTS

The median lesion volume was 5 mL (interquartile range [IQR]: 2-16 mL) (FB) and 16 mL (IQR: 2-27 mL) (VG), P = 0.133. The mean distance of the targets was 2.7 ± 1.1 mm (FB) and 2.9 ± 1.3 mm (VG), P = 0.456. Mean angle deviation was 2.6 ± 1.3 deg (FB) and 3.5 ± 2.1 deg (VG), P = 0.074. Diagnostic yield was 93% (25/27) in VG and 96% (25/26) in FB, P = 1.000. Mean operating time was 47 ± 26 minutes (FB) and 59 ± 31 minutes (VG), P = 0.140. One minor bleeding was encountered in the VG group. Overall patient discomfort was significantly higher in the FB group (visual analog scale score 2.5 ± 2.1 vs. 1.2 ± 0.6, P = 0,004).

CONCLUSIONS

The VG system proved to be comparable in terms of the trajectory accuracy, rate of complications and diagnostic yield compared with the "gold standard" represented by the traditional FB stereotaxy for patients undergoing brain biopsy. VG is also better accepted by patients.

Frameless Stereotactic Insertion of Viewsite Brain Access System with Microscope-Mounted Tracking Device for Resection of Deep Brain Lesions: Technical Report

The surgical management of deep brain tumors is often challenging due to the limitations of stereotactic needle biopsies and the morbidity associated with transcortical approaches. We present a novel microscopic navigational technique utilizing the Viewsite Brain Access System (VBAS) (Vycor Medical, Boca Raton, FL, USA) for resection of a deep parietal periventricular high-grade glioma as well as another glioma and a cavernoma with no related morbidity. The approach utilized a navigational tracker mounted on a microscope, which was set to the desired trajectory and depth. It allowed gentle continuous insertion of the VBAS directly to a deep lesion under continuous microscopic visualization, increasing safety by obviating the need to look up from the microscope and thus avoiding loss of trajectory. This technique has broad value for the resection of a variety of deep brain lesions.

Real-time magnetic resonance imaging-guided frameless stereotactic brain biopsy: technical note

OBJECTIVE

The object of this study was to assess the feasibility, accuracy, and safety of real-time MRI-compatible frameless stereotactic brain biopsy.

METHODS

Clinical, imaging, and histological data in consecutive patients who underwent stereotactic brain biopsy using a frameless real-time MRI system were analyzed.

RESULTS

Five consecutive patients (4 males, 1 female) were included in this study. The mean age at biopsy was 45.8 years (range 29-60 years). Real-time MRI permitted concurrent display of the biopsy cannula trajectory and tip during placement at the target. The mean target depth of biopsied lesions was 71.3 mm (range 60.4-80.4 mm). Targeting accuracy analysis revealed a mean radial error of 1.3 ± 1.1 mm (mean ± standard deviation), mean depth error of 0.7 ± 0.3 mm, and a mean absolute tip error of 1.5 ± 1.1 mm. There was no correlation between target depth and absolute tip error (Pearson product-moment correlation coefficient, r = 0.22). All biopsy cannulae were placed at the target with a single penetration and resulted in a diagnostic specimen in all cases. Histopathological evaluation of biopsy samples revealed dysembryoplastic neuroepithelial tumor (1 case), breast carcinoma (1 case), and glioblastoma multiforme (3 cases).

CONCLUSIONS

The ability to place a biopsy cannula under real-time imaging guidance permits on-the-fly alterations in the cannula trajectory and/or tip placement. Real-time imaging during MRI-guided brain biopsy provides precise safe targeting of brain lesions.

[Frameless stereotactic biopsy: diagnostic yield and complications]

OBJECTIVE

The aim of this study was to evaluate the variables that could modify the diagnostic yield of frameless stereotactic biopsy, as well as its complications.

MATERIALS AND METHOD

This was a retrospective study of frameless stereotactic biopsies carried out between July 2008 and December 2011 at Donostia University Hospital. The variables studied were size, distance to the cortex, contrast uptake and location.

RESULTS

A total of 70 patients were included (75 biopsies); 39 males and 31 females with an age range between 39 and 83 years. The total diagnostic yield in our series was 97.1%. For lesions >19mm, the technique offered a sensitivity of 95.2% (95% CI: 86.9-98.4) and specificity of 57.1% (95% CI: 25.0-84.2). The yield was lower for lesions within 17mm of the cortex: sensitivity of 74.6% (95% CI: 62.1-84.7) and specificity of 71.4% (95% CI: 29.0-96.3). Seven (10%) patients developed complications after the first biopsy and none after the second.

CONCLUSIONS

The diagnostic yield was lower for lesions less than 2cm in size and located superficially. In this series we did not observe an increased rate of complications after a second biopsy.

Neuronavigation in the surgical management of brain tumors: current and future trends

Neuronavigation has become an ubiquitous tool in the surgical management of brain tumors. This review describes the use and limitations of current neuronavigational systems for brain tumor biopsy and resection. Methods for integrating intraoperative imaging into neuronavigational datasets developed to address the diminishing accuracy of positional information that occurs over the course of brain tumor resection are discussed. In addition, the process of integration of functional MRI and tractography into navigational models is reviewed. Finally, emerging concepts and future challenges relating to the development and implementation of experimental imaging technologies in the navigational environment are explored.