Blessing N R Jaja1, Jetan Badhiwala2, James Guest3, James Harrop4, Chris Shaffrey5, Max Boakye6, Shekar Kurpad7, Robert Grossman8, Elizabeth Toups8, Fred Geisler9, Brian Kwon10, Bizhan Aarabi11, Mark Kotter12, Michael G Fehlings13, Jefferson R Wilson14. 1. From the Division of Neurosurgery and Spine Program University of Toronto and Toronto Western Hospital, Toronto, ON, Canada. 2. Division of Neurosurgery and Spine Program, University of Toronto, Toronto, ON, Canada. 3. Division of Neurosurgery, University of Miami, Miami, FL. 4. Division of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, PA. 5. Duke Spine Division, Duke University School of Medicine, Durham, NC. 6. Division of Neurosurgery, University of Louisville, Louisville, KY. 7. Division of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI. 8. Division of Neurosurgery, Methodist Hospital, Houston, TX. 9. Chicago Institute of Neurosurgery and Neuroresearch, RUSH University, Chicago, IL. 10. Division of Spine Surgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada. 11. Division of Neurosurgery, Shock Trauma, University of Maryland, Baltimore, MD. 12. Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom. 13. Division of Neurosurgery and Spine Program , Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada. 14. Division of Neurosurgery and Spine Program, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. jeffersonwilson7@gmail.com.
Abstract
OBJECTIVE: To test the hypothesis that sensorimotor complete traumatic cervical spinal cord injury is a heterogenous clinical entity comprising several subpopulations that follow fundamentally different trajectories of neurologic recovery. METHODS: We analyzed demographic and injury data from 655 patients who were pooled from 4 prospective longitudinal multicenter studies. Group based trajectory modeling was applied to model neurologic recovery trajectories over the initial 12-months postinjury and to identify predictors of recovery trajectories. Neurologic outcomes included: Upper Extremity Motor Score, Total Motor Scores and AIS grade improvement. RESULTS: The analysis identified 3 distinct trajectories of neurologic recovery. These clinical courses included: (1) Marginal recovery trajectory: characterized by minimal or no improvement in motor strength or change in AIS grade status (remained grade A); (2) Moderate recovery trajectory: characterized by low baseline motor scores that improved approximately 13 points; or AIS conversion of one grade point; (3) Good recovery trajectory: characterized by baseline motor scores in the upper quartile that improved to near maximum values within 3 months of injury. Patients following the moderate or good recovery trajectories were of younger age, had more caudally located injuries, a higher degree of preserved motor and sensory function at baseline examination and exhibited a greater extent of motor and sensory function in the zone of partial preservation. CONCLUSION: Cervical complete SCI can be classified into one of 3 distinct subpopulations with fundamentally different trajectories of neurologic recovery. This study defines unique clinical phenotypes based on potential for recovery, rather than baseline severity of injury alone. This approach may prove beneficial in clinical prognostication and in the design and interpretation of clinical trials in SCI.
OBJECTIVE: To test the hypothesis that sensorimotor complete traumatic cervical spinal cord injury is a heterogenous clinical entity comprising several subpopulations that follow fundamentally different trajectories of neurologic recovery. METHODS: We analyzed demographic and injury data from 655 patients who were pooled from 4 prospective longitudinal multicenter studies. Group based trajectory modeling was applied to model neurologic recovery trajectories over the initial 12-months postinjury and to identify predictors of recovery trajectories. Neurologic outcomes included: Upper Extremity Motor Score, Total Motor Scores and AIS grade improvement. RESULTS: The analysis identified 3 distinct trajectories of neurologic recovery. These clinical courses included: (1) Marginal recovery trajectory: characterized by minimal or no improvement in motor strength or change in AIS grade status (remained grade A); (2) Moderate recovery trajectory: characterized by low baseline motor scores that improved approximately 13 points; or AIS conversion of one grade point; (3) Good recovery trajectory: characterized by baseline motor scores in the upper quartile that improved to near maximum values within 3 months of injury. Patients following the moderate or good recovery trajectories were of younger age, had more caudally located injuries, a higher degree of preserved motor and sensory function at baseline examination and exhibited a greater extent of motor and sensory function in the zone of partial preservation. CONCLUSION: Cervical complete SCI can be classified into one of 3 distinct subpopulations with fundamentally different trajectories of neurologic recovery. This study defines unique clinical phenotypes based on potential for recovery, rather than baseline severity of injury alone. This approach may prove beneficial in clinical prognostication and in the design and interpretation of clinical trials in SCI.