American Society for Peripheral Nerve
ASPN Home ASPN Home Past & Future Meetings Past & Future Meetings

Back to 2023 Abstracts


Correlation Analysis of Strength and Patient Reported Outcomes in Nerve Transfer Surgery; Does MRC Accurately Represent Functional Outcome?
Matthew WT Curran, MD, MSc1; Kirsten Laine Marr, MD, MN-NP2; Michael J. Morhart, MD3; Jaret Olson, MD, FRCSC1; K. Ming Chan, MD, FRCPC4
1Plastic and Reconstructive Surgery, University of Alberta, Edmonton, AB, Canada; 2University of Alberta, Edmonton, AB, Canada; 3Department of Plastic and Reconstructive Surgery, University of Alberta, Edmonton, AB, Canada; 4Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, AB, Canada

Introduction: Motor recovery after nerve transfer surgery is often assessed according to the Medical Research Council (MRC) power scale. While this scale can be used to follow motor recovery, there often is a wide range of functional outcomes that are encompassed by a single grade. Despite this, MRC grades are often the primary end points of many studies. Alternative outcomes, such as force data, represents a quantifiable outcome that is perhaps more sensitive than MRC in detecting functional outcome changes. Methods: A retrospective review of 29 patients were analyzed. This group was comprised of fourteen patients that underwent an AIN end-to-end (ETE) nerve transfer, nine patients that had radial-to-axillary nerve transfers, and six patients that underwent Oberlin transfer. All patients needed to demonstrate MRC grade 4 recovery to be included. Force data such as grip, key pinch, shoulder abduction, elbow flexion and DASH were extracted. Force data was presented as raw values and as percentage of contralateral. Shapiro Wilk test was conducted to assess normality of the data. Correlation analysis was the used to analyze force and DASH data according to data normality. Significance was defined as p < 0.05.
Results: Fourteen patients underwent an AIN ETE transfer that had MRC grade 4 recovery, median follow-up of 33.5 months (25.75-43.25), a large range of grip strength (22.4 kg 50 kg), key pinch (0.8 kg 6.4 kg), and DASH (1.67 86.7). Spearman correlation analysis demonstrated a statistically significant correlation of grip strength and DASH (rho= -0.65; p=0.01). Normalized key pinch also demonstrated a statistically significant correlation with DASH (rho=-0.60; p=0.02). Nine patients underwent a radial-to-axillary nerve transfer, had MRC grade 4 recovery, and a median follow-up of 19 months (17-26) and also showed a statistically significant correlation of shoulder abduction and DASH (rho= -0.77; p= 0.02). And finally, six patients underwent an Oberlin transfer with MRC grade 4 recovery and a median follow up of 19.5 months (12-25.5). Spearman correlation analysis demonstrated a correlation of elbow flexion with DASH, but it was not statistically significant (rho= -0.55; p= 0.26).
Conclusions: There is large variability in force and DASH results among patients that have MRC grade 4 recovery. Force data directly correlated with patient reported outcomes. Force data represents a quantifiable and precise outcome that better predicts functional outcome, and further refines patients that would all be categorized into one MRC grade grouping by traditional end point metrics.


Back to 2023 Abstracts