Use of a novel ball-joint guide array for magnetic resonance imaging-guided cannula placement and convective delivery: technical note.

OBJECTIVE The objective of this study was to assess the feasibility, accuracy, effectiveness, and safety of an MRI-compatible frameless stereotactic ball-joint guide array (BJGA) as a platform for cannula placement and convection-enhanced delivery (CED). METHODS The authors analyzed the clinical and imaging data from consecutive patients with aromatic l-amino acid decarboxylase (AADC) deficiency who underwent infusion of adeno-associated virus (AAV) containing the AADC gene (AAV2-AADC). RESULTS Eleven patients (7 females, 4 males) underwent bilateral MRI-guided BJGA cannula placement and CED of AAV2-AADC (22 brainstem infusions). The mean age at infusion was 10.5 ± 5.2 years (range 4-19 years). MRI allowed for accurate real-time planning, confirmed precise cannula placement after single-pass placement, and permitted on-the-fly adjustment. Overall, the mean bilateral depth to the target was 137.0 ± 5.2 mm (range 124.0-145.5 mm). The mean bilateral depth error was 0.9 ± 0.7 mm (range 0-2.2 mm), and the bilateral radial error was 0.9 ± 0.6 mm (range 0.1-2.3 mm). The bilateral absolute tip error was 1.4 ± 0.8 mm (range 0.4-3.0 mm). Target depth and absolute tip error were not correlated (Pearson product-moment correlation coefficient, r = 0.01). CONCLUSIONS Use of the BJGA is feasible, accurate, effective, and safe for cannula placement, infusion MRI monitoring, and cannula adjustment during CED. The low-profile universal applicability of the BJGA streamlines and facilitates MRI-guided CED.