Introduction: Intrastriatal neural transplantation using multiple grafts is an experimental approach to the treatment of Huntington's disease (HD). Brain atrophy makes stereotactic plans in these patients a tedious procedure with a risk of suboptimal spatial distribution of the grafts in transplantation procedures. Here we present a self-developed software to optimize the surgical stereotactic planning for bilateral neurotransplantation procedures. It allows close to symmetrical distribution of the stereotactic coordinates in relation to the mid-commissural point (MCP), proposing automatically the planning coordinates for the first transplanted hemisphere and mirrored coordinates to be used in the contra-lateral hemisphere.

Methods: Twenty-two consecutive HD patients underwent bilateral stereotactic striatal transplantation. Two caudate nucleus and four putaminal tracks were planned bilaterally. For the second, contra-lateral transplantation, the coordinates were mirrored in order to determine contralateral targets and trajectories. Intra-individual comparison between software given coordinates and finally used coordinates was performed.

Results: No statistical significance was found comparing a) the differences between coordinates proposed by the software and the final coordinates and b) the distribution of the transplantation sites in relation to the midline for the right vs. left hemisphere. No intra- or postoperative transplantation-related adverse events occurred.

Conclusions: The use of model-based and mirrored coordinates allowed optimal spatial distribution of the grafts. Minor changes were required comparing right to left coordinates giving proof-of principle. The initial use of the software suggests that it may be useful in experimental transplantation trials where neural cell grafts are to be implanted into predefined target sites in the human brain, whether unilateral or bilateral.

Patient Care: The software presented here allowed us to achieve a fast determination of the stereotactic coordinates in relation to the MCP for the first surgery providing mirrored coordinates for the contralateral transplantation, facilitating an optimized spatial distribution of the grafts. The stereotactic trajectories have to be adapted for anatomical variations, according to the disease-related brain atrophy and to the presence of blood vessels. The proposed use of such a data base for coordinates can shorten stereotactic planning time and thus increase the safety of the overall procedure.

Learning Objectives: The model-based coordinates predicted by the software optimized the surgical planning, which is considered as a key part of the procedure. The presented technique can also be applied in neurotransplantation for other neurodegenerative diseases, for instance in patients with Parkinson’s disease. To the best of our knowledge, this is the largest reported patient series and therefore it was especially suited to create a database for target coordinates.

References: Clinical neurotransplantation protocol for Huntington's and Parkinson's disease. Lopez WO, Nikkhah G, Kahlert UD, Maciaczyk D, Bogiel T, Moellers S, Schültke E, Döbrössy M, Maciaczyk J. Restor Neurol Neurosci. 2013;31(5):579-95. doi: 10.3233/RNN-130317.