Application of diffusion tensor tractography in surgical resection of brainstem cavernous malformation

Objective To evaluate the application of preoperative diffusion tensor tractography (DTT) in the surgical management of brainstem cavernous malformation and its correlation with clinical outcomes. Methods The clinical data of 73 patients with brainstem cavernous malformations were analyzed retrospectively who were admitted to Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University from February 2013 to January 2016. Preoperatively, the bilateral corticospinal and medial lemniscus tracts of each patient were traced by DTT. The DTT scores were graded by the pattern of fiber tracts (1-4 scores). The surgical approach was determined according to the location of the fiber tracts and lesion. Intraoperatively, the lesion was resected by the fiber-merged navigation. Patients were postoperatively evaluated according to the modified Rankin scale (mRS) at different time points. The clinical factors were compared between the group with high DTT score and that with low DTT score. The relationship between the neurological function and preoperative DTT score was analyzed. Results Gross total resection was achieved in 68 cases (93.2%) while subtotal resection in 5 cases (6.8%). The average DTT scores of corticospinal tract and medial lemniscus tract were 1.83±1.04 and 1.97±1.46, respectively. The location and size of the lesion between the group with high DTT score and that with low DTT score were significantly different (93.2%). The final mRS score was lower than the initial one (P=0.027). The high DTT score of corticospinal tracts and the lesion diameter more than 2 cm were considered as factors negatively correlated with the patient's neurological function. Conclusion The application of DTT in the surgical resection of brain stem cavernous malformation could be helpful for the surgeon's choice of surgical approach, preventing intraoperative injury of fiber tract and improving the patient's clinical outcome. Key words: Brainstem; Hemangioma, cavernous, central nervous system; Diffusion tensor tractography; Neurosurgical procedures