Bipolar latissimus dorsi transposition and functional neuromuscular stimulation to restore elbow flexion in an individual with C4 quadriplegia and C5 denervation

Implanted neuroprosthesis for restoring arm and hand function in people with high level tetraplegia

OBJECTIVE

To develop and apply an implanted neuroprosthesis to restore arm and hand function to individuals with high level tetraplegia.

DESIGN

Case study.

SETTING

Clinical research laboratory.

PARTICIPANTS

Individuals with spinal cord injuries (N=2) at or above the C4 motor level.

INTERVENTIONS

The individuals were each implanted with 2 stimulators (24 stimulation channels and 4 myoelectric recording channels total). Stimulating electrodes were placed in the shoulder and arm, being, to our knowledge, the first long-term application of spiral nerve cuff electrodes to activate a human limb. Myoelectric recording electrodes were placed in the head and neck areas.

MAIN OUTCOME MEASURES

Successful installation and operation of the neuroprosthesis and electrode performance, range of motion, grasp strength, joint moments, and performance in activities of daily living.

RESULTS

The neuroprosthesis system was successfully implanted in both individuals. Spiral nerve cuff electrodes were placed around upper extremity nerves and activated the intended muscles. In both individuals, the neuroprosthesis has functioned properly for at least 2.5 years postimplant. Hand, wrist, forearm, elbow, and shoulder movements were achieved. A mobile arm support was needed to support the mass of the arm during functional activities. One individual was able to perform several activities of daily living with some limitations as a result of spasticity. The second individual was able to partially complete 2 activities of daily living.

CONCLUSIONS

Functional electrical stimulation is a feasible intervention for restoring arm and hand functions to individuals with high tetraplegia. Forces and movements were generated at the hand, wrist, elbow, and shoulder that allowed the performance of activities of daily living, with some limitations requiring the use of a mobile arm support to assist the stimulated shoulder forces.

Excitability of skeletal muscle during development, denervation, and tissue culture

A quantitative understanding of the bulk excitability of skeletal muscle tissues is important for the design of muscle tissue bioreactor systems, implantable muscle stimulators, and other systems where electrical pulses are employed to elicit contractions in muscle tissue both in vitro and in vivo. The purpose of the present study is to systematically compare the excitability of mammalian (rat) skeletal muscle under a range of conditions (including neonatal development, denervation, and chronic in vivo stimulation of denervated muscle) and of self-organized muscle tissue constructs engineered in vitro from both primary cells and cell lines. Excitability is represented by rheobase (R(50), units = V/mm) and chronaxie (C(50), units = microseconds) values, with lower values for each indicating greater excitability. Adult skeletal muscle is the most excitable (R(50) ~ 0.29, C(50) ~ 100); chronically denervated whole muscles (R(50) ~ 2.54, C(50) ~ 690) and muscle engineered in vitro from cell lines (C2C12 + 10T1/2) (R(50) ~ 1.93, C(50) ~ 416) have exceptionally low excitability; muscle engineered in vitro from primary myocytes (R(50) ~ 0.99, C(50) ~ 496) has excitability similar to that of day 14 neonatal rat muscle (R(50) ~ 0.65, C(50) ~ 435); stimulated-denervated muscles retain excellent excitability when chronically electrically stimulated (R(50) ~ 0.40, C(50) ~ 100); and neonatal rat muscle excitability improves during the first 6 weeks of development, steadily approaching that of adult muscle.

Neuromuscular electrical stimulation in neurorehabilitation

This review provides a comprehensive overview of the clinical uses of neuromuscular electrical stimulation (NMES) for functional and therapeutic applications in subjects with spinal cord injury or stroke. Functional applications refer to the use of NMES to activate paralyzed muscles in precise sequence and magnitude to directly accomplish functional tasks. In therapeutic applications, NMES may lead to a specific effect that enhances function, but does not directly provide function. The specific neuroprosthetic or "functional" applications reviewed in this article include upper- and lower-limb motor movement for self-care tasks and mobility, respectively, bladder function, and respiratory control. Specific therapeutic applications include motor relearning, reduction of hemiplegic shoulder pain, muscle strengthening, prevention of muscle atrophy, prophylaxis of deep venous thrombosis, improvement of tissue oxygenation and peripheral hemodynamic functioning, and cardiopulmonary conditioning. Perspectives on future developments and clinical applications of NMES are presented.

Tetraplegia Hand Activity Questionnaire (THAQ): the development, assessment of arm-hand function-related activities in tetraplegic patients with a spinal cord injury

STUDY DESIGN

Development of Tetraplegia Hand Activity Questionnaire (THAQ).

SETTING

Patients and spinal cord injury (SCI) professionals from five rehabilitation centres in the Netherlands and Belgium.

OBJECTIVE

To construct a disease-specific questionnaire to evaluate interventions to the arm-hand of tetraplegics in terms of gained and lost activities relevant to the patient.

METHODS

All arm-hand function-related activities were inventoried by examining existing scales and interviewing spinal cord injury patients and professionals in the field. Subsequently, item reduction was achieved; first, in the technical construction by incorporating all activities in an item list, then reducing the list by selecting the items most likely to be sensitive to change after surgical or functional electro stimulation interventions on the arm-hand as judged by an expert panel, using a Delphi method.

RESULTS

The arm-hand-related activity inventory comprised 652 activities. The technical construction of the items and the Delphi procedure resulted in a questionnaire with 153 items. The experts considered many of the 'new' activities more relevant for the evaluation of hand function interventions than those found in scales studied in the literature. This is reflected in a relatively large proportion of new activities (69%) for the item list of the THAQ, and even more in the domains work/admin/telecom (88%) and leisure (100%).

CONCLUSION

The questionnaire constructed to assess hand function-related activities contains relevant activities to evaluate arm-hand function-related interventions for tetraplegic SCI patients.

Improved kinematics of unrestrained arm raising in C5-C6 tetraplegic subjects after deltoid-to-triceps transfer

STUDY DESIGN

Prospective comparative study.

OBJECTIVE

To determine whether control of upper limb joint synergy during unrestrained arm raising involving shoulder and elbow flexion is modified by deltoid-to-triceps transfer.

SETTING

Rehabilitation unit for spinal cord injury patients, France.

METHODS

Five C6 subjects with C5-C6 tetraplegia sustained posterior deltoid-to-triceps transfer and were compared to a control group of 11 subjects. Kinematics of shoulder and elbow joints before, 6 month and 1 year after surgery, during straight-arm raising (SAR) in the plane of the scapula and hand-to-nape-of-neck movements (HNNMs) were explored. Motion was recorded with a six-camera Vicon motion analysis system and the data used to assess the coupling of elbow and shoulder flexion velocities (EFVs and SFVs) and extension velocities.

RESULTS

All subjects were initially assessed at 6.9 months (mean) postsurgery. Three of the upper limbs were assessed a second time (mean 17.9 months). The first assessment showed an increase in shoulder flexion amplitudes in tetraplegic subjects with presurgery shoulder flexion deficits. Peak SFVs and EFVs and extension velocities were slightly modified at the first postsurgery assessment and dramatically improved at the second assessment during both SAR and HNNM. Despite these increased velocities, joint coordination was only partially restored.

CONCLUSION

A restored elbow active extension improves the speed of elbow flexion. The additional improvement of shoulder motion emphasises the relation between joints in the control of arm movement.

Management of the paralyzed elbow in tetraplegia

The management of the paralytic conditions in tetraplegia requires understanding neural pathophysiology. A comprehensive rehabilitative and surgical plan requires a multidisciplinary approach. Prior to redistributing the muscle forces across the elbow, a supple osseo-articular platform must be created. The authors recommend PDT and BTT transfers and a FES neuroprosthesis. Future work in this field will advance the application of neuromodulation and its deployment in different neurophysiologic states.

Neuroprostheses for the upper extremity

Functional electrical stimulation (FES) neuroprostheses can be used to replace lost motor and sensory function in persons with neurological disorders. FES technology has subsequently been shown effective and safe in restoring hand function in adults with spinal cord injury. The freehand system consists of an implanted receiver-stimulator, an external shoulder position sensor, and an external control unit. Commands are originated by voluntary movement of the contralateral shoulder and are measured by the sensor. There are several types of electrodes: epimysial, intramuscular, nerve cuff, and intraneural. Neuroprostheses are recommended within the context of all available reconstructive options for the upper limbs. Voluntary tendon transfers are the first choice. The clinical outcomes as measured by improvement on scales of impairment, activities of daily living, and satisfaction are rewarding. The next step in improvement of the motor function of person with spinal cord injury will be the addition of a controllable second upper extremity and the elimination of additional external hardware.

Application of functional neuromuscular stimulation to children with spinal cord injuries: candidate selection for upper and lower extremity research

This paper summarizes the results of screening for participation in research programs involving functional neuromuscular stimulation (FNS). It examines the characteristics of a group of children and teenagers with spinal cord injuries (SCI) identified as potential candidates for FNS as defined by the rigorous inclusion criteria of the research studies. One hundred and thirteen children and teenagers under the age of 20 with cervical, thoracic or lumbar level spinal cord injuries were examined for inclusion in an experimental program of FNS to provide standing, walking, or prehension. Although biased towards adolescents with complete midthoracic and midcervical injuries, the age, sex, injury level, etiology, and neurological status of the sample coincided with previously published reports and consisted predominantly of teenage males injured in motor vehicle or sports related accidents. Approximately half of the individuals examined were physically appropriate for research participation without preparatory intervention. Treatment options to prepare individuals for FNS were identified in 25% of those considered inappropriate at the initial evaluation, indicating that the potential user population of clinical systems may be larger than estimates obtained from research applications. Peripheral denervation was the single most prevalent physical impediment to the application of FNS. Although the incidence of lower motor neuron (LMN) involvement was similar in subjects with tetraplegia and paraplegia, those with cervical lesions more frequently exhibited other medical complications that interfered with the application of FNS. Surgical procedures involving transfer of paralyzed but excitable muscles were identified in almost one third of the candidates with tetraplegia who were excluded due to denervation. Of those physically appropriate, psychological factors eliminated several candidates from consideration. Such concerns may also be addressed with suitable intervention in preparation for the clinical application of FNS. Almost 50% of those appropriate for FNS research elected to participate in the programs, with those declining citing the hospitalization, time and travel commitments as the primary factors influencing their decisions. Results suggest that FNS for standing, walking and hand grasp may be an option for a significant percentage of the pediatric SCI population.

Functional neuromuscular stimulation: outcomes in young people with tetraplegia

Percutaneous intramuscular functional neuromuscular stimulation (FNS) systems were fitted to the forearms of five adolescents with tetraplegia in an effort to provide active grasp and release. Two assessments designed at Case Western Reserve University to evaluate functional outcomes of FNS in adults were employed. The common object test (COT) was used to assess hand function during five activities of daily living (ADLs): eating, drinking, writing, brushing teeth and applying toothpaste. A usage survey provided information on the frequency of FNS use in environments outside of the laboratory. In addition, interviews were employed using open-ended questions to gain a deeper understanding of the perceptions of FNS in the adolescents' own environments. Based on the COT results, each adolescent was able to perform ADLs with and without FNS. However, FNS allowed unilateral function so that the extremity without FNS was freed to assist in balance or participate in bilateral tasks. Also, FNS reduced the need for multiple devices, providing users with the potential to perform activities in a variety of environments without transporting adaptive equipment. Those who reported using FNS most often obtained hard-bound school books, held pens during classroom and homework assignments, engaged in leisure activities and performed hygiene tasks. FNS was also used as a means to communicate and socialize through hand gestures. Well-known factors that influence the independence of people with tetraplegia also appeared to affect FNS use.