Spasticity causes abnormal muscle contraction. The muscles affected become overstimulated and contract forcibly. Patients will often have an imbalance between the muscles that flex and muscles that extend joints.
This imbalance can result in joints being pulled into abnormal positions. Eventually patients may develop joint contractures as the joints stiffen into the abnormal posture.
Causes
Spasticity in the upper limb is commonly seen in patients with cerebral palsy or acquired brain injury. Patient may develop spasticity following stroke. The extent of spasticity is quite variable dependent upon the degree of injury to the central nervous system.
Treatment
Non Surgical
Many patients with cerebral palsy will initially have botulinum toxin treatment to relax the affected muscles. After botulinum toxin injections, splintage and therapy is very important to try and maximise the benefit.
Unfortunately, the effect of botulinum toxin wears off after several months and in the course of growing up, children may require multiple episodes of botulinum toxin injections. In some cases, the effectiveness of the botulinum toxin becomes diminished over time and the patient may fail to respond as effectively.
Surgical
Surgical treatment has to be tailored to each individual patient’s needs. In high functioning patients with cerebral palsy, the goals of surgery can be quite challenging. Patients may aim to restore some active control of their affected joints. Most commonly this would involve trying to restore some wrist function.
With cerebral palsy, patients tend to hold their affected limb with the elbow in a flexed position and the wrist in a tightly flexed posture. It is also common to develop a "thumb in palm" deformity when the thumb becomes contracted into the palm. The fingers are sometimes held in a tightly flexed posture.
In some instances, tendons can be transferred to try and restore active wrist extension. Tendons can also be transferred to try and provide support of the thumb to reduce the deformity. In many cases, lengthening of the tendons may be required to try and reduce the overpowering effect of the muscles.
In more severely affected patients, the goals of surgery may be more limited. One of the reasons to consider surgery is for pain relief in joints that are tightly flexed and uncomfortable.
Many patients with "thumb in palm" deformity or tight flexion of the fingers will have difficulty with skin hygiene and may be unable to wash their hands fully due to the clenched posture of the fist. This is a good indication to consider a surgical release to try and hold the fingers and thumb in a more relaxed posture.
Often patients may not have any voluntary control of the affected limb and surgery may not provide any improvement in their ability to use the hand. Nevertheless, changing the position of the joints may make their hand and wrist more comfortable and may allow easier hygiene care. Having the wrist in a neutral position also makes dressing more straightforward.
Some patients may have tightly flexed elbow joints and have issues with skin maceration in the flexor creases. Again, release of the tight structures at the front of the elbow may allow the elbow to rest in a more neutral position.
Many patients will be very self-conscious and concerned about the cosmetic appearance of the wrist being held in a contracted posture. Having the arm realigned to rest in a neutral position often makes a big difference for patients’ self-confidence. Even though the function may not significantly improve, having the wrist and fingers in a neutral position can make a big difference for the patient.
This surgery is challenging and the goals can be limited. Nevertheless, small improvements in function have big impacts for patient comfort and confidence. Surgery can also assist patient carers by reducing difficulties with hygiene and dressing.