Predictors of wrist extensor muscle recovery following acute traumatic spinal cord injury: A model systems replication study.
Brandon M Johnson, Nathaniel K Johnson, Yan Li and 3 others
PMID 41085222WHAT IT FOUND
Three old clinical prediction rules for wrist extensor recovery after spinal cord injury are much less accurate than previously thought.
Positive predictive values dropped to 57% to 74%. Do not rely on a single rule to predict recovery or guide surgical referrals.
Key findings
01The positive predictive value for C5 sharp-dull discrimination was 56.9%, far lower than the 93.3% reported in the original study.
02The positive predictive value for initial C5 motor strength was 61.3%, and for initial C6 motor strength it was 73.9%, both lower than the 100% reported in the original study.
03A branched nomogram combining all three prediction rules achieved an area under the curve of 0.78, offering more nuanced prognostic information than any single rule.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The sample size of 123 patients is still relatively small compared to the breadth of the database. Data came from multiple centers with varying examiners, introducing potential interrater reliability issues. The initial exam timing was a proxy (admission to inpatient rehab) and averaged 17 days post-injury, later than the original study's one-week timeframe. The study only included patients with AIS A or B injuries, so results do not apply to AIS C or D. Left and right sides were analyzed as separate outcomes, which may affect generalizability to patient-level prognosis.
Declared interests
The research was supported by the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) and the National Institute of Child Health and Human Development (NICHD). No other conflicts were declared.
The easy way to misread this
Do not use the old prediction rules to definitively rule out surgical referral or promise recovery. The positive predictive values are now between 57% and 74%, meaning a significant portion of patients with 'good' initial signs will not recover functional wrist extension.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →