Innovative Technologies Are Restoring Upper Limb Functions in Paralysis Patients

A spinal cord injury (SCI) damages the connections in the spinal cord, disrupting communication between the brain and the body, which can result in lifelong disability. Approximately 500,000 new SCI cases are reported worldwide each year.

Spinal cord stimulation is an effective method to enhance upper limb mobility and function in patients with paralysis due to SCI or stroke. Improving motor recovery after SCI is essential for enhancing patients' quality of life. For tetraplegia patients, who cannot move their upper or lower limbs, regaining hand and arm function is a higher priority than restoring leg movement. 

At Houston Methodist, three interconnected areas of research are combining peripheral transfers, bioelectronics, transcutaneous spinal cord stimulation and other technologies to advance SCI treatments.

Improving upper limb function with noninvasive spinal cord stimulation

At his Neuromodulation & Recovery laboratory and Center for Neural Systems Restoration, Dr. Dimitry Sayenko, Associate Professor of Neurosurgery, is exploring invasive and non-invasive methods such as epidural and transcutaneous spinal cord stimulation in combination with task-specific upper limb rehabilitation to restore motor function after paralysis. Using advanced electrophysiology tools, including high-density electromyography, Dr. Sayenko has demonstrated that transcutaneous spinal cord stimulation can enhance muscle output, grip strength, and task-specific muscle activation patterns in individuals with tetraplegia after SCI.

Restoring hand function with nerve transfer surgery

Dr. Amir Faraji, Assistant Professor of Neurosurgery, is engaged in reinnervation surgeries such as nerve transfers to restore functional abilities in the hand or arm. Specifically, Dr. Faraji is taking donor nerves that are functional post-SCI, removing some nerve fibers and inserting them into healthy recipient nerves. In his Clinical Innovations laboratory, Dr. Faraji is also developing bioelectronic interfaces, investigating neural regeneration and translating innovative technologies into clinical trials.

Stimulating upper limb function with wireless spinal stimulation

Using preclinical models, Dr. Sean Barber, Assistant Professor of Neurosurgery, developed a novel method of ventral epidural spinal stimulation to improve motor function. Unlike traditional spinal cord stimulation, which targets the dorsal side of the spinal cord, this methodology directly stimulates the motor neurons located on the ventral side. Dr. Barber and his team created an innovative electrode with multiple contact points to access the ventral side. Its unique design allows for precise targeting of specific motor neurons to produce distinct movements. This methodology is safe and can be used alongside physical therapy to improve upper-limb motor function.

The most essential functions for SCI patients include the ability to grasp objects, use a toothbrush, pencil, or cell phone, feed themselves and make wheelchair transfers. Restoration of upper limb function can lead to some level of functional independence. This has a profound effect on the quality of life of individuals with upper limb paralysis or tetraplegia. Further research is needed to better understand the underlying mechanisms that govern functional recovery of the upper limbs post-SCI as well as neuroplasticity and neuromodulation.

 For further information on spinal cord stimulation research at Houston Methodist, please see the following papers:

 Nikhil Verma, Jeonghoon Oh, Ernesto Bedoy, Nikole Chetty, Alexander G Steele, Seo Jeong Park, Jaime R Guerrero, Amir H Faraji, Douglas Weber, Dimitry G Sayenko. Transcutaneous stimulation of the cervical spinal cord facilitates motoneuron firing and improves hand-motor function after spinal cord injury. J Neurophysiol. 2025 Jul 1;134(1):128-143. doi: 10.1152/jn.00422.2024.

 Jeonghoon Oh, Alexander G Steele, Blesson Varghese, Catherine A Martin, Michelle S Scheffler, Rachel L Markley, Yi-Kai Lo, Dimitry G Sayenko.Cervical transcutaneous spinal stimulation for spinal motor mapping. iScience. 2022 Aug 31;25(10):105037. doi: 10.1016/j.isci.2022.105037.

 Michelle S Scheffler, Catherine A Martin, Valerie Dietz, Amir H Faraji, Dimitry G Sayenko. Synergistic implications of combinatorial rehabilitation approaches using spinal stimulation on therapeutic outcomes in spinal cord injury. Clin Neurophysiol. 2024 Sep:165:166-179. doi: 10.1016/j.clinph.2024.06.015.

 Saad Javeed, Justin K Zhang, Jacob K Greenberg, Kathleen Botterbush, Braeden Benedict, Benjamin Plog, Vivek P Gupta, Christopher F Dibble, Jawad M Khalifeh, Huacong Wen, Yuying Chen, Yikyung Park, Allan Belzberg, Sami Tuffaha, Stephen Shelby Burks, Allan D Levi, Eric L Zager, Amir H Faraji, Mark A Mahan, Rajiv Midha, Thomas J Wilson, Neringa Juknis, Wilson Z Ray. Impact of Upper Limb Motor Recovery on Functional Independence After Traumatic Low Cervical Spinal Cord Injury. J Neurotrauma. 2024 May;41(9-10):1211- 1222. doi:10.1089/neu.2023.0140.

 Saad Javeed, Jacob K Greenberg, Justin K Zhang, Benjamin Plog, Christopher F Dibble, Braeden Benedict, Kathleen Botterbush, Jawad M Khalifeh, Huacong Wen, Yuying Chen, Yikyung Park, Allan J Belzberg, Sami Tuffaha, Stephen S Burks, Allan D Levi, Eric L Zager, Amir H Faraji, Mark A Mahan, Rajiv Midha, Thomas J Wilson, Neringa Juknis, Wilson Z Ray. Association of upper-limb neurological recovery with functional outcomes in high cervical spinal cord injury. J Neurosurg Spine. 2023 May 26;39(3):355-362. doi: 10.3171/2023.4.SPINE2382.

 Saad Javeed, Christopher F Dibble, Jacob K Greenberg, Justin K Zhang, Jawad M Khalifeh, Yikyung Park, Thomas J Wilson, Eric L Zager, Amir H Faraji, Mark A Mahan, Lynda J Yang, Rajiv Midha, Neringa Juknis, Wilson Z Ray. Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia. JAMA Netw Open. 2022 Nov 1;5(11):e2243890. doi:10.1001/jamanetworkopen.2022.43890.

 Matthew K Hogan, Sean M Barber, Zhoulyu Rao, Bethany R Kondiles, Meng Huang, William J Steele, Cunjiang Yu, Philip J Horner. A wireless spinal stimulation system for ventral activation of the rat cervical spinal cord. Sci Rep. 2021 Jul 21;11(1):14900. doi: 10.1038/s41598-021-94047-1.

 Abdullah K Afridi, Alexander G Steele, Catherine Martin, Dimitry G Sayenko, Sean M Barber. Ventral epidural stimulation for motor recovery after spinal cord injury: illustrative case. J Neurosurg Case Lessons. 2024 Sep 16;8(12):CASE24155. doi: 10.3171/CASE24155.

 Giuliano Taccola, Sean Barber, Phillip J Horner, Humberto A Cerrel Bazo, Dimitry Sayenko. Complications of epidural spinal stimulation: lessons from the past and alternatives for the future. Spinal Cord. 2020 Oct;58(10):1049-1059. doi: 10.1038/s41393-020-0505-8. Epub 2020 Jun 23.