Researchers from the Medical University of Vienna and the University of Applied Sciences have developed an algorithm for replacing a nonfunctional hand with a bionic prosthesis for patients with brachial plexus injuries, according to findings published in the Journal of Neurosurgery.
“For more than 25 years, I have dealt with patients suffering from devastating peripheral nerve lesions,” Oskar C. Aszmann, MD, PhD, a researcher from the Medical University of Vienna and senior author of the study, said in a press release. “Bionic reconstruction, as described in this paper, has been a real game-changer since it offers hope and real help for patients who otherwise have none.”
To develop the algorithm, researchers recruited patients who sought treatment for global brachial plexus injuries at the Center for Advanced Restoration of Extremity Function from 2011 to 2015. Of the 34 patients with injuries that led to loss of hand function, 16 qualified for bionic reconstruction, the release noted. Sufficient follow-ups were obtained from five patients at least 3 months after final prosthetic fitting. Final functional outcome measurements were taken using the Action Arm Research Test, the Southampton Hand Assessment Procedure and the DASH questionnaire.
According to the release, the algorithm researchers developed for replacing a nonfunctional hand with a bionic prosthesis can have up to seven steps, which include:
- Physical and psychological patient assessment, in which the patient must show useful shoulder and elbow function, but no motor ability of sensation in the hand. Patients must also demonstrate the ability to face the challenges of reconstruction;
- Identification of electromyographic signals in the forearm, as two separate signals are necessary to control a bionic hand;
- Optional surgery to perform selective nerve transfer and/or transplantation of healthy muscle to improve nerve conduction and muscle activation in the forearm if there are fewer than two electromyographic signals;
- Brain training to allow the patient to target reinnervated muscles to control hand and forearm movement;
- Hybrid hand fitting and training to use a prosthetic device using the patient’s biosignals prior to amputation;
- Elective amputation of a nonfunctional hand; and
- Replacement of the biological hand with a myoelectric prosthetic device, followed by additional training and functionality testing.
Among the five patients who completed follow-up assessments, partial hand function was restored in all, according to the release. In addition, deafferentation pain, which had been severe in three of the five follow-up patients, lessened after they became accustomed to the bionic hand.
Hruby LA, et al. J Neurosurg. 2017;doi: 10.3171/2016.6.JNS16154.
Disclosure: The researchers report no relevant financial disclosures.