A combination of age and test results can accurately predict whether a wheelchair-bound spinal injury patient will ever walk again.
The new forecasting method developed by European experts could help the counselling and rehabilitation of people who have been traumatically paralysed in accidents or conflict.
It may also help researchers decide which patients are most suitable for trials of new spinal injury treatments.
Scientists studied 1,442 newly-injured patients at 19 centres to find a way of telling which of them would be able to walk independently after a year.
The prediction model involves carrying out four tests of leg muscle motor response and the ability to feel light touches on the knee and ankle within 15 days of an injury.
Combining these results with a patient's age - whether he or she is under or over 65 - provides a scoring system for assessing the probability of walking.
The chances of walking scores ranged from minus 10 to 40. A score of minus 10 means there is no possibility of a patient walking independently after a year. A score of 10 corresponded with a 35% chance of walking, and scores of 30 and above indicated that a patient was virtually certain to walk.
The technique was found to be highly accurate, getting the prediction right 95% of the time.
Currently, doctors try to predict a patient's chances of walking from a widely used grading system for spinal injuries. But this method provides no more than a good guess.
Study leader Dr Joost van Middencorp, from Nijmegen Medical Centre in the Netherlands, and colleagues, wrote in The Lancet medical journal: "Our prediction rule, including age and four neurological tests, can give an early prognosis of an individual's ability to walk after traumatic spinal cord injury, which can be used to set rehabilitation goals and might improve the ability to stratify patients in interventional trials."
In an accompanying comment, Professor Wagih El Masri and Dr Naveen Kumar, from the University of Keele, Staffordshire, wrote: "Further studies are needed to assess the power of the various prognostic indicators and assess their value when applied at different times after injury."Reuse content