# Upper Limb Orthotics/Partial Lesion of C7
## Case study

The patient is a 70-year-old independent female who suffered a fall from a ladder resulting in a fracture in C7 4 months ago. Consequently, she experiences slight weakness when extending her wrist and lack of finger movement. Passive and resisted range of motion of her wrist and metacarpal-phalangeal joints were conducted to determine the strength of the movements based on the muscle strength grading scale. Her wrist extensor muscles were graded a 3 and her finger flexors were rated a 2. Additionally, strength was tested with lateral grasp (lateral pinch) with a pinch meter and palmar grasp (power grip) tests which the patient had difficulty performing. Neurological tests were conducted and passed Based on her motor function, C7 was affected. She was diagnosed with incomplete motor function with function below C7 intact. Due to poor management of her hand, she is unable to produce full extension of her wrist.

## Evidence
### Introduction

The spinal cord is part of an essential pathway in which the brain communicates with the body. The spinal cord contains white matter and neuron cell bodies known as gray matter that conduct a sensory or motor path (Kirshblum et al, 2011). A disruption to the pathway will interfere with function innervated by the affected spinal level, and a common mechanism of injury is blunt trauma such as motor vehicle accidents and impacts at high speeds. Injury to a spinal level can impact motor and sensory function can be exclusive to that level or include all the inferior levels. Tetraplegia or ‘Quadriplegia’ is often used to describe the loss of motor or sensory function in the cervical level, often a disruption in the spinal canal (Kirshblum et al, 2011) and results in loss of upper limb function. Similarly, brachial plexus lesions will impair upper limb function but differ from SCI due impairment limited to the upper limb and the differing mechanism of injury, which is due to forces acting on the shoulder and causing trauma to the network of nerves in the brachial plexus (Brunelli, 1991).

### Classification

The American Spinal Injury Association (ASIA) devised a classification system for spinal cord injuries, categorising the level of impairment on a scale known as the ASIA Impairment Scale. Through conducting clinical assessments on suspected spinal cord injuries, the level of injury can be determined and whether sensory or motor function is impaired. To determine the motor level affected, manual muscle grading is utilised by determining what spinal level lacks key muscle activity. For C7, it is the triceps which enable elbow extension. If a level lacks the key muscle function, the rostral spinal nerves will increase in muscle grade strength (Kirshblum et al, 2011). Muscle grade is ranked 0-5, where 0= paralysis, 1= muscle contraction with no movement, 3= active full range of motion against gravity and 5= active full range of motion against gravity, with resistance.
Sensory examination is employed with “joint movement appreciation and position sense tests” (Kirshblum et al, 2011), which involve patients identifying the upper limb movement the examiner is producing whilst blinded and identifying the static position the upper limb is in. Alternatively, touch and pressure tests can be conducted.
A spinal cord injury can be described as complete, incomplete or normal based on the following characteristics: Table 1: ASIA Impairment Scale
| Type | Characteristics |
| A | Complete: No sensory or motor function is preserved |
| B | Incomplete (Sensory): Sensory function preserved; motor function impaired |
| C | Motor function below spinal level is preserved OR more than half the major muscles below spinal level have a muscle strength grade below 3 |
| D | Incomplete (Motor): Motor function below spinal level is preserved; at least half major muscles below spinal cord have a muscle strength grade greater than 3. Voluntary anal sphincter contraction maintained. |
| E | Normal |

### Anatomy and Physiology

Motor function derives from the ventral roots, which contain efferent nerve fibres that arise from neurons of the ventral horn and extend to skeletal muscles. The pathway contains neural cells that synapse at the terminal of one cell and the receptor of the proceeding cell within the peripheral nervous system. The pathway involves constant conversion of chemical messages to electrical impulses. Dorsal roots on the other-hand contain sensory fibres from sensory neurons in the dorsal root ganglia. The peripheral receptors under the dermis conduct electrical impulses to the spinal cord and follow a complex system of neurons (Marieb & Hoehn, 2010). The intrinsic pathway describes the pathways that interconnect neural groups, as Propriospinal fibres propagate potentials in the peripheral nervous system and is composed of unmyelinated ascending and descending fibres. White matter in the spinal segment contains neural bodies and gray matter contains axons of the neuron (McDonald and Sadowsky, 2002).
A fracture or injury to a spinal level will result in the disruption of blood supply to the nervous system and damage to the neural cells. Initially, haemorrhage occurs in the central gray matter, resulting in the increase blood flow in the spinal cord. The cord swells and occupies most of the space in the spinal canal. As venous blood pressure exceeds normal limits, vascular tissue constricts to auto-regulate the blood flow, leading to hypotension and release of toxic chemicals from neural tissue that attack surrounding cells (McDonald and Sadowsky, 2002). Hypofusion slows or blocks the propagation of axon potentials along axons. A proliferation of apoptosis in neural tissue can occur weeks following trauma to the spine (Lee, Zipfel and Choi, 1999). An injury to the central gray matter containing nerve-cell bodies will confine the injury to the dermis and muscles innervated by that spinal level. Whereas, injury to the white matter of a spinal level will render the person a tetraplegic, loss of function of the bladder and mobility of the lower limbs (McDonald and Sadowsky, 2002).
The ascending tract in the spinal cord is the transmission of sensory information from receptors to the higher level of the central nervous system. The fibres enter the central nervous system from the dorsal column. These fibres carry receptive information to the brain from the dermis that are related to tactile, two-point discrimination of pressure, vibration, joint position and limb position and proprioception (Marieb & Hoehn, 2010). The area of skin innervating sensory nerves are organised in a dermatome map. Termination at any point of the pathway of a spinal level from injury at the spinal cord or in the nerve network will result in loss of sensation at that dermatome. C7 represents the areal of skin over the 2nd to 4th digits of the fingers.
The descending pathway contains motor nerve fibres that originate from the brain cell nuclei (Marieb & Hoehn, 2010) and is associated with voluntary movement, posture, balance, muscle tone and reflex activity. Each spinal level innervates a group of muscles that produce movement at a joint. A myotome map represents the movements each spinal level produces. C7 is responsible for elbow extension, wrist flexion and extension and digit flexion and extension. However C7 does not act on these movements alone, but acts along with C6 and C8. A partial lesion means that some of these movements are affected.

### Mechanism of injury

The mechanism of spinal cord injury is due to fractures, displaced bone fragments, discs and ligament tears as a result of traction and compressive forces applied on the vertebral column (McDonald & Sadowsky, 2002). The vertebral column is in a vulnerable position when cervical lordosis is lost during 30 degree flexion of the head due to a significantly reduced ability of the vertebral column to dissipate axial compressive forces (Bonham & Greaves, 2011). Cervical spine fractures were sustained typically through axial load mechanisms resulting from falls or diving accidents (Thompson et al, 2009).

### Orthotic treatment options

According to Thorsen et al (2013), arm and hand function is not affected below C7. Orthotic management for injuries to C7 aims to help preserve movement in the hand with tenodesis in the wrist. Tenodesis is the passive movement of fingers based on wrist action: extending wrist will enable flexion of the fingers and flexing the wrist will extend fingers (Atkins, Clark & Walters, 2003). Wrist flexion with the assistance of gravity will allow the hand to open and grasp can be produced with wrist extension, enabling flexion of the second and third digit agaisnst the thumb. Therefore, a wrist-driven, wrist-hand orthosis can enable the wrist to “transfer power” to the fingers to enable grasp by wrist extension with an "actuating lever at the wrist joint" that controls the degree of hand movement (Atkins, Clark & Waltersm 2013). Static wrist-hand orthosis are recommended for higher cervical injuries, however, according to Atkins, its function is to reduce risk of contractures and deformities.

### Comparison of orthotic treatment options

The classification will determine the method of treatment for the patient. Before proceeding to treat lesion at C7 operatively, it essential to establish whether the lesion is preganglionic or postganglionic (Bonham and Greaves, 2011). Preganglionic injuries are more intricate to treat, and muscle function can be restored through surgical intervention. Factors that determine the appropriate management for a patient include age, sex, site of lesion and number of roots involved. (Nanago, 1998). Patients under the age of 50 are likely to face complications through surgical intervention.
Nagano et al found that elbow flexion was restored in 82% of patients who were treated with intercostal nerve surgery within the first 6 months of sustaining the injury. Surgery is only suggested for patients with a severe injury, and it is important to proceed with surgery before denervated muscles become irreversibly atrophic. Poor results were observed in nerve reconstruction surgeries when the procedure is performed more 9 months following injury (Bentolila et al., 1999).
Through electromyelography as a diagnostic device, if the damage is determine to be non-degenerative, conservative management can be utilised to treat and prevent uncontrolled movements of the upper limb that may cause discomfort with the fitting of a brace. Additionally, physical therapy should be practiced, with passive range of movements at the joints to maintain muscle power and mobility (Bonham and Greaves, 2011).
The symptoms of weakness in finger and thumb flexor muscles and wrist extensor muscles can be managed conservatively by the fitting of an orthotic device early in the rehabilitation process. Equipment and therapeutic regimes involving passive range of motion exercises can be adapted additionally. Conventional treatment is often preferred over surgery, as costs are more equitable and does not involve high risks.