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

Intentional Insertion of Air to Predict the Diagnostic Accuracy of Stereotactic Biopsy and a Uniform Grading System for Reporting

BACKGROUND AND OBJECTIVES

Stereotactic biopsies are a relatively safe and reliable way of tissue diagnosis and characterization of eloquent area lesions/neoplasm. However, predicting the accuracy of the site of biopsy with the desired/planned site is not always possible. We describe a technique to identify the precise location of the biopsy site in the post-operative computed tomography (CT) scan using the injection of a low volume of air into the biopsy cannula.

METHODS

Hundred consecutive biopsies were performed in 80 adults/20 children (59 males/41 females, median age 51 years) over 3 years, consisting of 75 frameless and 25 frame-based stereotactic biopsies. After the biopsy specimens had been collected, a small volume of air (median 1 cc) was injected into the site. Post-operative CT was done within 4 hours of the biopsy to see the site of the air bubble, and the same was correlated with the histopathological accuracy.

RESULTS

Intra-cranial air in the selected target was present in 95 patients (Grade 1 and 2), while the air was seen in the track (Grade 3) in 3% and at an unrelated site (Grade 4) in 2% of cases. Both Grade 4 biopsies were negative on histopathology (diagnostic yield = 98%). Two negative biopsies were reported, which were both predicted with the Grade 4 biopsy. The grading allowed uniform reporting across series and eliminated the chance of upgrading/downgrading the report due to wrong site sampling within the lesion/neoplasm.

CONCLUSION

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

Pushing the boundaries of accuracy and reliability during stereotactic procedures: A prospective study on 526 biopsies comparing the frameless robotic and Image-Guided Surgery systems

INTRODUCTION

A 12-year long, prospective, single center study was conducted, comparing two frameless systems for brain biopsies: ROSA robotic-assisted stereotaxy and BrainLab Varioguide image-guided stereotaxy (Image Guided Surgery, IGS).

METHOD

All consecutive adult and pediatric patients undergoing frameless brain biopsies were included. Successfully achieving diagnosis was the primary endpoint, analysis of all periprocedural complications was the secondary endpoint, and the tertiary endpoint was the length of the procedure, with the aim of assessing of the learning curve for each operator over time. The results for the ROSA robot and the Varioguide system were compared and benchmarked to data from the literature.

RESULTS

We performed 526 on 516 patients, 314 with the ROSA robot (Group A) and 212 with the IGS Varioguide (Group B). Histological diagnosis was achieved in 97.4% of cases in Group A, versus 93.3% in Group B (p < 0.05). No statistically significant difference was found for secondary and tertiary endpoints. The complication rate appeared similar between the 2 frameless systems, with a hemorrhagic complications rate of 3.5% in Group A and 4.7% in Group B. Permanent neurological deterioration was only recorded in 0.8% of cases from Group B. Mortality was recorded in 0.3% in Group A and 0.4% in Group B.

CONCLUSION

This study provides evidence to confirm that robotic surgery lives up to its promises of increased safety, accuracy, and reliability.

Optimized Intraoperative Imaging for Stereotactic Planning with a Multiaxial Robotic C-arm System: Technical Note and Case Series

BACKGROUND

 The preoperative preparation of the planning dataset for frame-based stereotactic brain biopsy is often associated with logistical effort and burden on the patient. Intraoperative imaging modalities need to be investigated to overcome these limitations.

OBJECTIVE

 The objective of the study was to develop and apply a new method for the intraoperative acquisition of the planning dataset with the multiaxial robotic C-arm system Artis zeego.

METHODS

 An indication-customized dose-reduced protocol for Artis zeego was developed and implemented into the workflow. A sample of 14 patients who had undergone intraoperative imaging with Artis zeego was analyzed. A sample of 10 patients with conventional preoperative imaging by cranial computed tomography (CT) was used as a control group. Outcomes were compared with regard to target deviation, diagnostic value of the biopsies, complications, and procedure time.

RESULTS

 In all patients, a suitable intraoperative planning dataset could be acquired with Artis zeego. Total procedure time was shorter for the Artis zeego group (p = 0.01), whereas time in the operating room area was longer in the Artis zeego group (p = 0.04). Biopsy results were diagnostic in 12 patients (86%) in the Artis zeego group and in 8 patients (80%) in the control group. There were no significant differences in target size, trajectory length, or target deviation.

CONCLUSION

 Intraoperative imaging for frame-based stereotactic brain biopsy with Artis zeego is an easy and feasible method. Accuracy is comparable to conventional CT, whereas radiation exposure could be additionally reduced. It allows a significant reduction of the total procedure length and improves the comfort for the patient and staff.

Fusion of Preoperative and Postoperative Imaging May Predict the Diagnostic Yield of Stereotactic Needle Brain Biopsies

BACKGROUND

Stereotactic needle brain biopsy is a commonly used neurosurgical procedure. However, up to 15% of biopsies result in undiagnostic pathology reports. Repeat biopsy or continued management without a diagnosis are often considered after undiagnostic biopsies. There have been no reports about the role of postoperative imaging in predicting the diagnostic yield of stereotactic biopsies.

METHODS

We retrospectively assessed all stereotactic biopsies performed over an 11-year period. We performed fusion of immediate postoperative computed tomography (CT) with preoperative MRI, to document whether the air bubble in the postoperative CT was located within the targeted lesion. We then evaluated the association of this fusion-based accuracy assessment with the diagnostic yield of the biopsy.

RESULTS

Fewer than 5% of biopsies did not have an air bubble on postoperative CT. A total of 226 biopsies were performed for 219 patients. In our sample, 213 of 226 biopsies were accurate (94.2% accuracy rate), and 203 of 226 biopsies gave a definitive diagnosis (89.8% diagnostic rate). In those cases where the fusion was accurate, the diagnostic rate was 93.9%. When the fusion was inaccurate, the diagnostic rate was only 23.1% (odds ratio 51.5, 95% confidence interval 12.6-210.44, P < 0.001). Of all patient, imaging, surgical, and admission parameters, the only parameter that correlated with diagnostic outcome of the biopsy was the fusion construct accuracy.

CONCLUSIONS

Fusion of immediate postoperative CT with preoperative imaging is predictive of the diagnostic rate. In cases where the pathology report following a biopsy is not diagnostic, this fusion may be useful in making decisions regarding repeat biopsy or considering other diagnostic options.