Stereotactic biopsy of brainstem lesions: 21 years experiences of a single center

Abstract

Stereotactic biopsies are procedures performed to obtain tumor tissue for diagnostic examinations. Cerebral lesions of unknown entities can safely be accessed and tissue can be examined, resulting in correct diagnosis and according treatment. Stereotactic procedures of lesions in highly eloquent regions such as the brainstem have been performed for more than two decades in our department. In this retrospective study we focus on results, approaches, modalities of anesthesia, and complications. We performed a retrospective analysis of our prospective database, including 26 patients who underwent stereotactic biopsy of the brainstem between April 1994 and June 2015. All of the patients underwent preoperative MRI. Riechert-Mundinger-frame was used before 2000, thereafter the Leksell stereotactic frame was used. After 2000 entry and target points were calculated by using BrainLab stereotactic system. We evaluated histopathological results as well as further treatment; additionally we compared complications of local versus general anesthesia and complications of a frontal versus a trans-cerebellar approach. Median age of all patients was 33 years, and median number of tissue samples taken was 12. In all patients a final histopathological diagnosis could be established. 5 patients underwent the procedure under local anesthesia, 21 patients in general anesthesia. In 19 patients a frontal approach was performed, while in 7 patients a trans-cerebellar approach was used. Complications occurred in five patients. Thereby no significant difference was found with regard to approach (frontal versus trans-cerebellar) or anesthesia (local versus general). Stereotactic biopsies even of lesions in the brainstem are a save way to obtain tumor tissue for final diagnosis, resulting in adequate treatment. Approach can be trans-cerebellar or frontal and procedure can be performed either under local or general anesthesia without significant differences concerning complication rate.

Stereotactic biopsies of brainstem lesions: which approach?

“…The main limitation is the small sample size of patients of our cohort compromising a better estimate of complication rate and the diagnostic yield of brain stem biopsies in general. However, our results are in line with previous studies including larger numbers of patients [ 5 , 11 , 15 , 16 ]. Furthermore, the current results are based only on observations reflecting our targeting strategy and no conclusions can be drawn if one of the two suggested approaches would yield lower complication rates.…”

“…We used both supratentorial (transfrontal or transparietal) and transcerebellar approaches. Both approaches have been described and used by several groups [ 4 , 5 , 11 , 15 , 16 , 22 ]. However, information about the choice of the trajectory related to their precise location in the brainstem has not been specifically addressed in previous studies.…”

Response to letter: “Stereotactic biopsies of brainstem lesions: dilemma on the best trajectory”

“…On the other side, case series of brainstem stereotactic biopsies performed through a supratentorial transfrontal approach seemed not to show an increased complication rate [1,5]. Nevertheless, as discussed in our publication [2], we also believe that crossing the entire brainstem or part of it to reach a lesion has intrinsically more complication rate, as, in our experience, (transient) neurological deficits may appear without bleeding and not necessarily at the biopsy location.…”

Outpatient stereotactic brain biopsies

“…The biopsy-targeted location is notably not included in these criteria, because, as we discussed above, the timing of post-biopsy complications is not depending on the biopsied lesion location. However, as a structure associated with critical functions, biopsies targeting the brainstem are associated with more neurological complications [28,30,31] and could be less easily performed in an outpatient setting. In our study, we performed only one brainstem lesion biopsy in a meticulously selected patient with immediate and long-term favorable outcomes.…”