One year of home-based daily FES in complete lower motor neuron paraplegia: recovery of tetanic contractility drives the structural improvements of denervated muscle.

Abstract

OBJECTIVE:

Spinal cord injury (SCI) causes muscle atrophy, which is particularly severe, due to inability to perform tetanic contractions, when lower motor neurons (LMN) are involved. We performed a longitudinal study in 25 Europeans suffering from complete conus cauda syndrome from 0.7 to 8.7 years comparing functional and structural thigh muscle properties before and after 2 years of home-based daily training by functional electrical stimulation (FES). The mid-term results after 1 year and preliminary muscle biopsy observations at project end-point from a subset of subjects are here reported.

METHODS:

Muscles were electrically stimulated at home by means of large surface electrodes and a custom-designed stimulator. The poor excitability of the LMN denervated muscles was first improved by twitch-contraction training. Then, tetanic contractions against progressively increased loading were elicited. Finally, standing-up exercises were daily performed. The bulk of thigh muscle was estimated by transverse computer tomography (CT) scan and force measurements. Needle biopsies of vastus lateralis were harvested before and after 2 years of FES.

RESULTS:

The 1 year home-based daily FES training induced: (1) very similar increases in muscle excitability and contractility in right and left legs; (2) feasibility to elicit tetanic contractions by means of train-stimulation with about ten times improvement of muscle force; (3) increase in the 26% of muscle bulk, as shown by CT scan analyses, improving appearance of limbs and muscle cushioning; (4) myofiber size increase (+94%) in a small series of muscle biopsies obtained after 2 years of FES. None of the subjects that performed 1 year home-based daily FES training (20 persons) had worsened their functional class, while 20% (4/20) improved to functional class 4, that is, the ability to stand.

DISCUSSION:

The European Union (EU) Project Rise shows that 'home-based daily FES training' is a safe and effective therapy that may maintain life-long physical exercise by active muscle contraction (FES is the only option for denervated muscle) as a procedure to recover the early-lost tetanic contractility of denervated muscle, and to counteract muscle atrophy in order to prevent clinical complications.

• Authors: Helmut Kern, Ugo Carraro, Nicoletta Adami, Christian Hofer, Stefan Loefler, Michael Vogelauer, Winfried Mayr, Rudiger Rupp, Sandra Zampieri
• Journal: Neurological research (Neurol Res) Vol. 32 Issue 1 Pg. 5-12 (Feb 2010) ISSN: 1743-1328 [Electronic] England
• PMID: 20092690 (Publication Type: Journal Article)

Topics

• Adult
• Electric Stimulation Therapy
• Europe
• Female
• Humans
• Longitudinal Studies
• Male
• Middle Aged
• Motor Neurons
• Muscle Contraction (physiology)
• Muscle Denervation
• Muscle, Skeletal (diagnostic imaging, innervation, pathology, physiology)
• Muscular Atrophy
• Musculoskeletal Manipulations
• Paraplegia (pathology, physiopathology, therapy)
• Recovery of Function
• Thigh
• Time Factors
• Tomography, X-Ray Computed
• Treatment Outcome
• Young Adult