R. Loch Macdonald


Associate Scientist, Keenan Research Centre for Biomedical Science

Research Programs


My major research interests are in the field of aneurismal subarachnoid hemorrhage and cerebral vasospasm. We are investigating causes of delayed neurological deterioration after subarachnoid hemorrhage using animal models and testing hippocampal electrophysiology and function, animal behavior, learning and memory and changes in gene expression and function. We also are studying mechanisms of large artery vasospasm after aneurismal subarachnoid hemorrhage and effects of intracerebral and subdural hemorrhage on the brain. All of this work is laboratory-based as well as clinical with clinical trials and patient-based studies conducted testing similar hypotheses.

Recent Publications

  1. Germans, MR, Jaja, BNR, de Oliviera Manoel, AL, Cohen, AH, Macdonald, RL. Sex differences in delayed cerebral ischemia after subarachnoid hemorrhage. J. Neurosurg. 2017; :1-7. doi: 10.3171/2017.3.JNS162808. PubMed PMID:28862545 .
  2. Alotaibi, NM, Ibrahim, GM, Wang, J, Guha, D, Mamdani, M, Schweizer, TA et al.. Neurosurgeon academic impact is associated with clinical outcomes after clipping of ruptured intracranial aneurysms. PLoS ONE. 2017;12 (7):e0181521. doi: 10.1371/journal.pone.0181521. PubMed PMID:28727832 PubMed Central PMC5519166.
  3. Pasarikovski, CR, Alotaibi, NM, Al-Mufti, F, Macdonald, RL. Hypertonic Saline for Increased Intracranial Pressure After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review. World Neurosurg. 2017;105 :1-6. doi: 10.1016/j.wneu.2017.05.085. PubMed PMID:28549643 .
  4. Eagles, ME, Jaja, BNR, Macdonald, RL. Incorporating a Modified Graeb Score to the Modified Fisher Scale for Improved Risk Prediction of Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage. Neurosurgery. 2017; :. doi: 10.1093/neuros/nyx165. PubMed PMID:28419304 .
  5. Ku, JC, Alotaibi, NM, Wang, J, Ibrahim, GM, Schweizer, TA, Macdonald, RL et al.. Internet search volumes in brain aneurysms and subarachnoid hemorrhage: Is there evidence of seasonality?. Clin Neurol Neurosurg. 2017;158 :1-4. doi: 10.1016/j.clineuro.2017.04.008. PubMed PMID:28412503 .
  6. Guha, D, Macdonald, RL. Perioperative Management of Anticoagulation. Neurosurg. Clin. N. Am. 2017;28 (2):287-295. doi: 10.1016/j.nec.2016.11.011. PubMed PMID:28325463 .
  7. Hänggi, D, Macdonald, RL. Response by Hänggi and Macdonald to Letter Regarding Article, "Randomized, Open-Label, Phase 1/2a Study to Determine the Maximum Tolerated Dose of Intraventricular Sustained Release Nimodipine for Subarachnoid Hemorrhage (NEWTON [Nimodipine Microparticles to Enhance Recovery While Reducing Toxicity After Subarachnoid Hemorrhage])". Stroke. 2017;48 (4):e114. doi: 10.1161/STROKEAHA.117.016603. PubMed PMID:28283608 .
  8. Murphy, A, de Oliveira Manoel, AL, Macdonald, RL, Baker, A, Lee, TY, Marotta, T et al.. Changes in Cerebral Perfusion with Induced Hypertension in Aneurysmal Subarachnoid Hemorrhage: A Pilot and Feasibility Study. Neurocrit Care. 2017;27 (1):3-10. doi: 10.1007/s12028-017-0379-6. PubMed PMID:28244000 .
  9. Grasso, G, Alafaci, C, Macdonald, RL. Management of aneurysmal subarachnoid hemorrhage: State of the art and future perspectives. Surg Neurol Int. 2017;8 :11. doi: 10.4103/2152-7806.198738. PubMed PMID:28217390 PubMed Central PMC5288992.
  10. Alotaibi, NM, Guha, D, Ahuja, CS, Spears, J, Muller, PJ, Tucker, WS et al.. History of neurosurgery at University of Toronto: the St. Michael's story. J. Neurosurg. 2017; :1-9. doi: 10.3171/2016.9.JNS161119. PubMed PMID:28128690 .
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Affiliations & Other Activities

  • Associate Scientist, Li Ka Shing Knowledge Institute
  • Professor, Surgery/Neurosurgery, University of Toronto
  • Keenan Endowed Chair, Surgery, St. Michael’s Hospital