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A Force Meter to Assess Lower Limb Motor Function After Epidural Analgesia
  1. Anthony H. Ilsley, Ph.D., G.Dip.Comp.,
  2. John L. Plummer, Ph.D., G.Dip.Appl.Stats.,
  3. Peter Brownridge, F.R.C.A., F.A.N.Z.C.A. and
  4. Michael E. Jones, F.A.N.Z.C.A., Ph.D., G.Dip.Appl.Stats.
  1. From the Department of Anesthesia and Intensive Care, Flinders Medical Centre, Bedford Park, South Australia.
  1. Address correspondence and reprint requests to Dr. Peter Brownridge, Department of Anaesthesia and Intensive Care, Flinders Medical Centre, Bedford Park, South Australia 5042.


Background and Objectives. Current methods of assessing lower limb motor function using low-dose epidural analgesia are either too insensitive (Bromage scale) or too cumbersome for use during labor. Accordingly, we have designed a force meter that quantitatively measures isometric muscle power of the lower limbs during peak voluntary exertion.

Methods. The force meter was tested for linearity using calibrated reference weights. Measurements were made on two occasions (separated by an interval of approximately 5 years), and differences in response were assessed by regression analysis. Departure from linearity was examined by a lack of fit test.

Results. There was no significant nonlinearity in response over the range 0-15 kg, nor was there any significant difference in slope between the two functional modes of this device. The device overread slightly at the higher weights.

Conclusions. The force meter described was found to be sufficiently accurate and suitable for the quantitative assessment of lower limb motor function after epidural analgesia during labor.

  • Force meter
  • epidural analgesia
  • labor
  • assessment
  • lower limb motor function
  • isometric muscle power.

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  • The authors thank the Flinders Medical Centre Department of Biomedical Engineering and, in particular, Mr. Nigel Kelley for the stirrup concept of the design and general construction of the force meter, and Mr. Rik Fronsko for assistance with testing.