Connolly SJ, McIntyre A, Mehta, S, Foulon BL, Teasell RW. (2014). Upper Limb Rehabilitation Following Spinal Cord Injury. In Eng JJ, Teasell RW, Miller WC, Wolfe DL, Townson AF, Hsieh JTC, Connolly SJ, Noonan VK, Loh E, McIntyre A, editors. Spinal Cord Injury Rehabilitation Evidence. Version 5.0: p 1-77.
Raineteau and Schwab (2001) defined a spinal cord injury (SCI) as a lesion within the spinal cord that results in the disruption of nerve fibre bundles that convey ascending sensory and descending motor information. A SCI at the cervical level results in tetraplegia, the loss of hand and upper limb function with impairment or loss of motor and/or sensory function. In incomplete spinal cord injuries, some neural transmission can still pass through the spinal cord, but it is often fragmentary or distorted which leads to additional neurological complications such as chronic pain or spasticity. Tetraplegia results in impairment of function in the arms, as well as in the trunk, legs and pelvic organs. It is estimated that cervical SCI accounts for approximately 50% of all people living with SCI (Steeves et al. 2007). The loss of upper limb function, especially the use of the hands is one of the most significant and devastating losses an individual can experience. The use of the upper extremities is critical in completing basic activities of daily living such as self-feeding, dressing, bathing and toileting. Mobility needs such as transfers from surface to surface, transitional movements such as rolling, bridging and sit to lying down, crutch walking and wheeled mobility are also completed using their arms (Snoek et al. 2004). The level at which the injury or lesion occurs and the completeness of the lesion (incomplete or complete) indicate the level of independence of the person (Ditunno 1999).
The Paralyzed Veterans of America (PVA) have published a clinical practice guideline (CPG), “Outcomes Following Traumatic Spinal Cord Injury: Clinical Practice Guidelines for Health Care Professionals,” that outlines the expected skills and outcomes that a person is expected to acquire and achieve at each significant level of injury (Consortium for Spinal Cord Medicine 1999). As medical care of the spinal cord injured person has improved, life expectancy now approaches the rest of the population. Secondary complications from SCI and aging are ongoing challenges and include pain, contractures and upper limb musculoskeletal injuries (Sipski & Richards 2006).
Hanson and Franklin (1976) compared sexual function to three other impairments in patients with SCI; approximately 76% of the subjects gave the highest priority to upper extremity function. Snoek et al. (2004) surveyed the needs of patients with SCI and found a high impact and high priority for improvement in hand function in those with tetraplegia comparable to that for bladder and bowel dysfunction. A recent study by Anderson (2004) found similar results in which 48.7% of persons with tetraplegia (3.3% of persons with paraplegia) reported that regaining arm and hand function would most improve their quality of life. In the same study, Anderson (2004) reported that women and men with tetraplegia had similar priorities (53.2% to 48.3%) and the priority of regaining arm and hand function did not change whether someone was injured 0-3 years or more than 3 years post SCI. Anderson (2004) reported that recovering even partial arm and hand function may have a significant impact on independence.
Given the above, the initial care, management, rehabilitation and prevention of injuries in the upper limb of those with tetraplegia are of great importance in maximizing and maintaining independence. Management of the tetraplegic upper limb tends to be eclectic involving traditional rehabilitation interventions of task directed training in which clients perform many repetitions of movements relevant to activities of daily living (ADL), use of orthosis (splints and adaptive devices) and upper extremity surgery. According to Murphy and Chuinard (1998), management and care of the upper limb can be divided into three phases: the acute, the subacute and the reconstructive phase. Bryden et al. (2005) proposed a similar hierarchy of upper extremity functional restoration for individuals with tetraplegia. This includes the provision of conservative treatment methods followed by surgical restoration using residual motor functions and increasing or augmenting voluntary functions with functional electrical stimulation (FES) for maximal upper limb function. The aims of the first two phases of rehabilitation are to prevent complications, to achieve optimal functioning within the limits of the neurological deficit, and to create optimal conditions for the reconstructive phase (Bedbrook 1981; Curtin 1994; Harvey 1996; Keith & Lacey 1991). In the latter phase, various surgical options and functional electrical stimulation (FES) are available to improve positioning and stabilization of the arm as well as key and palmar grasp function (Johnstone et al. 1988; Peckham et al. 2001; Snoek et al. 2000; Triolo et al. 1996; Waters et al. 1996). The new clinical practice guidelines by the Consortium for Spinal Cord Medicine (2005) emphasize the prevention of upper limb injuries among individuals with tetraplegia to maintain independence.
Although there is no overall consensus regarding the management of the tetraplegic upper limb, Hummel et al. (2005), Snoek et al. (2005) and the Consortium for Spinal Cord Medicine (2005) provide excellent discussions and recommendations.
There is agreement that restoration of hand function is an important goal in rehabilitation. It is also worth noting that there are very few upper extremity tests that accurately evaluate upper limb function in this population (van Tuijl et al. 2002). Curtin (1994) and Krajnik and Bridle (1992) noted a great inconsistency in evaluation and documentation of the tetraplegic upper limb between therapists.
Several studies have explored increased hand function as a result of reconstructive surgery and/or neuroprosthesis. Although these, and many other treatment options exist, have proven to improve the overall functioning and functional independence of the person with tetraplegia, clinical practice has shown that suitable candidates for reconstructive surgery or FES interventions often do not accept the treatment that is offered (Snoek et al. 2004). According to Moberg (1975), over 60% of the tetraplegic population could benefit from reconstructive surgery and it continues to be widely advocated (Snoek et al. 2004). Curtin et al. (2005) reported in their study that reconstructive surgery is underutilized in this population reporting that fewer than 10% of persons with tetraplegia actually undergo surgical reconstruction. Reconstructive surgeries such as muscle/tendon transpositions of the intact arm or hand muscles are designed to substitute for lost motor function (van Tuijl et al. 2002). Despite this, controversy still exists among clinicians as to whether or not to perform reconstructive surgeries and the benefits of reconstructive surgery have not been clarified with good quality randomized clinical trials (Harvey et al. 2001). Gorman et al. (1997) deduced that 11% of the tetraplegic population could be candidates for an implanted FES device (Freehand System). Most implanted FES devices are usually combined with augmentative and substitutional reconstructive surgery (Keith et al. 1996).
The main focus in rehabilitation of the spinal cord injured person is compensation of functional loss and using those parts of the sensorimotor system, which are still intact (van Tuijl et al. 2002). Research findings regarding neuroplasticity and neurological recovery of the spinal cord also include current rehabilitation practices that focus on strategies to restore function lost after SCI as significant recovery of function is observed after incomplete and even complete SCI (Beekhuizen 2005; Bradbury et al. 2002; Buchuli & Schwab 2005; Curt et al. 2008; Kirshblum et al. 2004; Marino et al. 1999; Waters et al. 1994). There is emerging evidence demonstrating and highlighting the importance of understanding the motor control strategies that the central nervous system (CNS) uses to govern hand movements in abled individuals. This information may be useful in guiding the rehabilitation process after cervical SCI and ensuring that the exercises performed for the hand and upper limb are effective for restoring functional ability (Backus 2010). The literature is reporting on the presence of muscle synergies that are a motor control paradigm that is being actively investigated (Bizzi et al. 2008; Cheung et al. 2005; d’Avella et al. 2003; Overduin et al. 2008).
This body of research puts forth the theory that there is a modular approach to motor control, where the CNS activates predefined combinations of muscles, rather than explicitly controlling individual muscles (Zariffa et al. 2012a). This could have implications in neurorehabilitation treatment implementation where there is explicit retraining of muscle synergies that are known to be useful in the able bodied population. It is that functional performance might be improved across a broad range of tasks (Zariffa et al. 2012a). To date most of the muscle synergy studies have explored the arm with a limited number of studied investigating the existence of muscle synergies in the hand (Zariffa et al. 2012a). Zarriffa et al. (2012a) investigated if there any synergies present in able-bodied individuals while using different types of hand grips relevant to ADLs such as pulp to pulp pinch, cylindrical grasp and lateral key pinch and attempted to determine whether the presence or absence of these synergies after SCI is correlated with functional abilities. There were several time-invariant synergies observed to occur consistently in a substantial proportion of able-bodied subjects and in the SCI population there was evidence that similar synergies existed but in different proportions and no clear relationship was found between the functional abilities of subjects with SCI and those subjects deviation from able-bodied synergy patterns. Further, Zariffa et al. (2012a) found that the most common synergy in the able-bodied population was EDC and EIP for finger extension and FDS and FCU for wrist flexion used to position the hand during grasping activities. In SCI the most common synergy was FCR and ECR for stabilizing the wrist and DII and TEMG for independent thumb movement (Latash et al. 2010; Santello et al. 1998; Weiss et al. 2004). Further research and investigation is required to determine how this information can be transferred into the treatment of the hand and upper limb of the SCI injured person for improving functional task performance.