Ambulation

Traumatic spinal cord injury (TSCI) is a debilitating condition of sudden onset that can have devastating consequences, with a tremendous impact on both the psychological and social well-being of patients. The ability to reliably predict the potential for independent walking after injury is important for counseling patients and their families with accurate information, and guiding strategies for treatment, rehabilitation and reintegration into the community. A reliable prognosis of a patient's potential for functional recovery can help clinicians better predict recovery trajectories, with the hope of alleviating patient anxiety and informing clinical decisions.

This calculator is intended for use by clinicians. The user must input variables based on the ISNCSCI examination, which requires accurate and reliable assessments by a clinician with experience in this assessment.

This calculator is not recommended to be used by persons with SCI. Instead, we encourage persons with SCI to consult with a clinician to discuss whether this prediction model is applicable to their situation.

This calculator should be used to assist with patient management in the acute setting and early rehabilitation, using ISNCSCI examination information assessed within the first 15 days of injury.

The calculator has been developed using data from patients with TSCI and has not been tested for use in patients with non-traumatic SCI (NTSCI).

The application of this tool may be most helpful in the assessment of patients presenting with injury severity of AIS B or C at admission, as their potential for recovery is variable and they may benefit the most from estimates of long-term functional capabilities. Patients presenting with an injury severity of AIS A or D have recovery trajectories that are more predictable (AIS A - low likelihood of walking, AIS D - high likelihood of walking), making this tool of limited value for that group.

All results must be interpreted within the context of the patient's full clinical profile. This calculator provides a probability score based on a published equation using multivariable logistic regression.¹

A 50% cut-off is used to predict the likelihood of being an independent walker 1-year after injury, and further translated into probability values related to the functional outcome (FIM).

• A probability of < 50%: individual is predicted to not have independent walking ability 1-year after injury.
• A probability of ≥ 50%: individual is predicted to gain independent walking ability 1-year after injury.

An independent walker is defined as someone who is able to walk without assistance from another person but may use a walking aid (e.g. walker, cane, etc.). Anyone who requires the assistance or supervision of another person to walk, or is unable to walk is not considered to be an independent walker.

Ambulation is a web-based app for predicting independent walking outcomes after TSCI. The clinical prediction rule was developed by Hicks et al,¹ using multivariable logistic regression (LR) analyses on a large prospective database of patients with TSCI.

The user inputs the variables required to calculate the prediction rule score through weighted coefficients. The prediction score is inputted into an equation, resulting in a value that represents the predicted likelihood of walking independently, 1-year after TSCI.

	Hicks et al.
Cohort	The Canadian Rick Hansen Spinal Cord Injury Registry (RHSCIR)
Cohort size	278
Period	2004 - 2014
Outcome measure	FIM locomotion Non-independent walker: FIM 1 - 5 Independent walker: FIM 6 - 7
Clinical prediction variables	1. Age at injury 2. Motor score of quadriceps femoris (L3) muscle 3. Light touch sensation of gastrocsoleus (S1) dermatome
Area under receiver-operating-characteristics curve	0.866
P value	<0.001
95% confidence interval	0.816–0.916
Journal & publication date	The Spine Journal, 2017

A comparison of the following clinical scenarios illustrates the clinical utility of Ambulation.

Case 1

A 22-year-old male involved in a motor vehicle accident presents to emergency department with a T12 chance fracture with severe canal stenosis. A diagnosis of traumatic SCI is made and the acute physical examination by the attending physician reveals an L3 motor score of 3, and an S1 light touch sensation (LTS) score of 1. The calculated likelihood of walking independently would be 71%. Based on a probability ≥ 50%, the model would predict that this patient will likely be able to independently walk 1-year after his injury.

Case 2

A 68-year-old male was brought into the emergency department after sustaining a SCI due to a fall from a height within his home. He was admitted to the spinal unit of a tertiary care hospital where the orthopedic surgeon assessed the patient, revealing a neurological examination with an L3 motor score of 3, and an S1 LTS score of 1. The calculated likelihood of walking independently would be 23%. Based on a probability < 50%, the model would predict that this patient will likely not be able to walk independently 1-year after the TSCI.

Two similar clinical scenarios have been presented with long-term functional outcomes predicted by the Hicks et al. clinical prediction rule. In each case, the prediction for long-term independent walking ability would have implications for counselling the patient and informing their rehabilitation.

1. Sturt R, Hill B, Holland A, New PW, Bevans C. Validation of a clinical prediction rule for ambulation outcome after non-traumatic spinal cord injury. Spinal Cord. 2020;58(5):609-615. doi:10.1038/s41393-019-0386-x
2. Phan P, Budhram B, Zhang Q, et al. Highlighting discrepancies in walking prediction accuracy for patients with traumatic spinal cord injury: an evaluation of validated prediction models using a Canadian Multicenter Spinal Cord Injury Registry. Spine J. 2019;19(4):703-710. doi:10.1016/j.spinee.2018.08.016
3. van Silfhout L, Peters AEJ, Graco M, Schembri R, Nunn AK, Berlowitz DJ. Validation of the Dutch clinical prediction rule for ambulation outcomes in an inpatient setting following traumatic spinal cord injury. Spinal Cord. 2016;54(8):614-618. doi:10.1038/sc.2015.201
4. Belliveau T, Jette AM, Seetharama S, et al. Developing Artificial Neural Network Models to Predict Functioning One Year After Traumatic Spinal Cord Injury. Arch Phys Med Rehabil. 2016;97(10):1663-1668.e3. doi:10.1016/j.apmr.2016.04.014
5. van Middendorp JJ, Hosman AJF, Donders ART, et al. A clinical prediction rule for ambulation outcomes after traumatic spinal cord injury: a longitudinal cohort study. Lancet. 2011;377(9770):1004-1010. doi:10.1016/S0140-6736(10)62276-3
6. Zörner B, Blanckenhorn WU, Dietz V, EM-SCI Study Group, Curt A. Clinical algorithm for improved prediction of ambulation and patient stratification after incomplete spinal cord injury. J Neurotrauma. 2010;27(1):241-252. doi:10.1089/neu.2009.0901