Factors Affecting the Diagnostic Yield of Frame-Based Stereotactic Intracranial Biopsies

Novel application of robot-guided stereotactic technique on biopsy diagnosis of intracranial lesions

Introduction

This study was performed to examine whether there is a link between the application of three types of robot-guided stereotactic biopsy techniques and the diagnostic rate of intracranial lesion biopsy.

Methods

The study involved 407 patients who underwent robot-guided stereotactic intracranial lesion biopsy at Xuanwu Hospital of Capital Medical University from January 2019 to December 2021. Age, sex, lesion characteristics, lesion distribution, surgical method, and target path depth were assessed for their impact on the biopsy diagnostic rate.

Results

The patients' mean age was 42.1 years (range, 6 months-82 years). All patients underwent robot-assisted stereotactic brain biopsy using one of three different systems: a ROSA robotic system (n=35), the CAS-R-2 (n=65), or the REMEBOT domestic robotic system (n=307). No significant difference was found in the diagnostic rate of positive histopathological findings or the mean time of surgery among the three biopsy modalities. The diagnostic rate was 93.86%. Multiple linear regression analysis showed that age, sex, and biopsy modality did not affect the diagnostic rate n>0.05), whereas enhancing lesions and smaller-volume lesions (≤l cm3) were significantly correlated with the diagnostic rate (p = 0.01). Lesions located in the suprasellar and pineal regions were significantly associated with the negative diagnostic rate (p<0.05).

Conclusion

The presence of enhancing lesions, lesion location, and lesion volume significantly affected the diagnostic rate of brain biopsy. Age, sex, lesion depth, and biopsy modality did not significantly affect the diagnostic rate. All three procedures had high safety and effectiveness.

Indicators of correct targeting in stereotactic biopsy of intracranial lesions

Background:

Confirmation of whether a stereotactic biopsy was performed in the correct site is usually dependent on the frozen section or on novel tumor-specific markers that are not widely available. Immediate postoperative computed tomography (CT) or magnetic resonance (MR) is routinely performed in our service after biopsy. In this retrospective study, we have carefully analyzed these images in an attempt to determine the presence of markers that indicate appropriate targeting.

Methods:

Medical records and neuroimages of patients who underwent stereotactic biopsy of intracranial lesions were reviewed. The following variables were assessed: age, sex, anatomopathology, lesion site, complications, diagnostic accuracy, and the presence of image markers.

Results:

Twenty-nine patients were included in this case series. About 96.6% of the biopsies were accurate according to the permanent section. Of the 86.2% of patients with intralesional pneumocephalus on the postoperative images, 51.7% additionally presented petechial hemorrhage. In 13.8% of the cases, no image markers were identified.

Conclusion:

This is the first report of intralesional pneumocephalus and petechial hemorrhage as indicators of appropriate targeting in stereotactic biopsy. In the majority of the cases, an immediate postoperative head CT, which is widely available, can estimate how adequate the targeting is. To use intralesional pneumocephalus/ petechial hemorrhages as not only postoperative but also as intraoperative markers of appropriate targeting, it is advised that the surgical wound should be temporarily closed and dressed after the biopsy so that the patient can undergo a CT/MR scan and be checked for the presence of theses markers before removing the stereotactic frame.

Comparison of frame-less robotic versus frame-based stereotactic biopsy of intracranial lesions

OBJECTIVE

Robotic guidance might be an alternative to classic stereotaxy for biopsies of intracranial lesions. Both methods were compared regarding time efficacy, histopathological results and complications.

METHODS

A retrospective analysis enrolling all patients undergoing robotic- or stereotactic biopsies between 01/2015 and 12/2018 was conducted. Trajectory planning was performed on magnetic resonance imaging (MRI). With the Robotic Surgery Assistant (ROSA), patient registration was accomplished using a facial laser scan in the operating room (OR), immediately followed by biopsy. In stereotaxy, patients were transported to the CT for Leksell Frame registration, followed by biopsy in the OR.

RESULTS

The average overall procedure time amounted in robotics to 169 min and in stereotaxy to 179 min (p = 0.005). The difference was greatest for temporal targets, amounting in robotics to 161 min and in stereotaxy to 188 min (p = 0,0007). However, the average time spent purely in the OR amounted in robotics to 140 min and in stereotaxy to 113 min (p < 0.001). In 150 robotic biopsies, diagnostic yield amounted to 98%, in 266 stereotactic biopsies to 91%. Symptomatic postoperative hemorrhages were observed in 3 patients (2%) in robotic biopsy and 7 patients (2,7%) in stereotactic biopsy.

CONCLUSION

Robotics showed a shorter overall procedure time as there is no need for a transport to the CT whereas the pure OR time was shorter in stereotaxy due to skipping the laser registration process. Diagnostic yield was higher in robotics, most likely due to case selection, complication rates were equal.

Evaluation of 311 contemporary cases of stereotactic biopsies in patients with neoplastic and non-neoplastic lesions-diagnostic yield and management of non-diagnostic cases

Stereotactic biopsies are an established tool for obtaining diagnosis of unclear brain lesions. However, non-diagnostic biopsies still occur. We aimed to analyze the contemporary diagnostic yield of stereotactic biopsies, predictors for non-diagnostic biopsies, outcome, and follow-up strategy after non-diagnostic biopsy. We conducted a single-center retrospective study of 311 adult patients undergoing stereotactic biopsies due to a newly diagnosed lesion at our department between 2012 and 2018. Patient data regarding comorbidities, presenting symptoms, imaging features, and non-invasive diagnostic procedures were obtained. The overall diagnostic yield was 86.2% and differed significantly between the various suspected diagnosis groups and was the highest when suspecting primary brain tumor compared with non-neoplastic lesions (91.2% vs. 73.3%, p > 0.001). Predicators for non-diagnostic biopsies were small lesion size, lack of contrast-enhancement, presence of sepsis, or underlying hemato-oncological disease. In case of non-diagnostic biopsy, a re-biopsy was performed in 12 cases, revealing a final diagnosis in 75%. In 16 cases, empiric therapy was started based on the suspected underlying disease. Close follow-up was performed in the remaining 15 cases. We showed that stereotactic biopsy is a safe procedure with reasonable diagnostic yield even for non-neoplastic lesions, when non-invasive diagnostic was inconclusive. In addition, we developed treatment recommendations for cases of non-diagnostic biopsies.