Have you ever experienced traffic on a freeway and wondered why? Without a single red light, you’d expect constant movement, yet your car and the cars surrounding you are unable to move an inch forward. Contrary to expectations, it is the nonstop green lights themselves that allow the jam in traffic. Without a buffer to stop vehicles from clogging up the road, any slight pause taken by a car ahead leads to a downstream reaction that completely halts all cars behind.
Medically speaking, spasticity is equivalent to a muscular traffic jam. More definitively, it is a condition in which muscles of a certain body region are continuously contracted— due to little inhibitory stimuli on motor neurons. And so, bereft of red lights, the muscles are overly activated, resulting in tight sensations, extreme stiffness and an ironic inability for movement or speech. Essentially, the traffic on a freeway analogy works precisely because of this irony: despite the “green lights” or excessive motor activity on a biological level, most of the debilitating symptoms are negative, related to the “traffic jam” or the lack of ability to move.
Now you must be wondering, okay I understand what causes spasticity physiologically, but how does the prerequisite of less inhibition on motor neurons come about in the first place? Typically, other diagnoses that negatively impact the brain and spinal cord are associated with the possibility of developing spastic pain. And so, spasticity can be considered as a potential side condition of a diverse number of medical complications to the brain and spinal cord, including spinal cord and traumatic brain injuries, stroke, multiple sclerosis (MS), cerebral palsy, meningitis and Parkinson’s disease.
In terms of how spasticity can be evaluated at bedside, most physicians will be able to recognize spasticity via thorough medical history and physical examination. For people with spasticity, the faster you attempt to stretch affected muscles, the more resistance you are faced with. And patients with lesions of the spinal cord, instead of lesions of the brain, experience an enormous, long-lasting reflex contraction upon the lightest touch to the lower extremity. Clinical scales that are useful in quantifying spastic muscles include the Physician’s Rating Scale measuring gait pattern and range of motion, the Ashworth Scale measuring the level of rigidity in muscle tone, and the Spasm Scale measuring the number of spasms in a certain time interval. Accompanying the spasticity for almost all patients is tremendous and intense pain from flexor spasms contracting and dystonic muscles.
With 12 million people worldwide affected by spasticity, there are essentially 12 million people experiencing pain and disability to the point of stillness in their affected region. And so, management of spasticity becomes especially important. The good news is just as there are a variety of hindrances at the central nervous system that can lead to spasticity, there are a variety of ways to manage the condition. The strength lies in the diversity of the approaches. With many possible routes, the treatment plan that ultimately emerges for each patient is molded in an individualized style, dependent on both their medical and social history. For some, no treatment is also an option, depending on the goals of the patient and the severity of the muscle spasms.
To start, there are standard medications that can be used to alleviate the debilitating physical impact of spasticity. It is important to note that some people will see most progress using a combination of medications rather than one alone. The focus for most of these drugs, however, is on increasing the inhibition of motor neurons. Many of these drugs do this by increasing the neurotransmitter GABA, which ultimately acts as the main inhibitor of the central nervous system. Thus, the increased GABA slows down motor activity, which then removes the tightness that is preventing motion. The result is comfortable and proper movement. Valium, a type of benzodiazepine, is one popular example of a medication that manages spasticity by enhancing GABA.
But things get more complicated when you look at baclofen, a different medication with a similar mechanism. Baclofen can be taken either orally, or in more severe cases, through a pump that is surgically implanted in the abdomen of a patient. This alternative method is referred to as intrathecal baclofen (ITB), and because it delivers the baclofen directly to spinal fluid, it has less side effects and is more effective in its reduction of spastic pain.
Close to the baclofen pump in concept but more conservative is the administering of very small amounts of botox via injections. These injections are made at sites determined by the quality of the spasticity and where the pain is localized. Botox reduces spasticity by preventing the neurotransmitter acetylcholine from releasing, which relaxes and loosens the muscle. Movement and comfort, like with the oral medications that act on GABA, are made more feasible after tension dissipates. The impact of the injections typically last for 2 weeks, and there is constraint in the number of repeat injections that can be performed.
The most liberal and risky form of management is surgery, such as selective dorsal rhizotomy (SDR), during which nerve fibers that send signals from the muscles to the spinal cord are cut. This strategy is useful for patients with a very particular medical background and presenting situation, and so the physician managing the spasticity will check off certain criteria before even offering the surgery as a possibility. It is primarily for spasticity in the lower extremities that completely prevents walking or causes the legs to lock into an unpleasant position. Only the stiffness fizzles out, while other functions for walking are maintained. Opposite of surgery is the most conservative method—using orthotics and positioners, along with occupational and physical therapies, to maximize muscular function and find ways to both adapt and restore so activities of daily living can be more easily performed.
Why stay stuck in severe traffic and miss out on all the places you could reach, when there are several routes taking you where you want to go faster? The fact is, managing spastic pain is doable in more than just one way, and the treatment plan can be changed as you and your physician contemplate your progress and goals. From physical therapy and oral medication to surgery, the possibilities are open to get you moving your affected muscles properly again. While reaching your pre-spasticity level may not be practical, pain management— and rehabilitation more generally— is about building you up from your weakest point until you find a new normal with maximal function and minimal pain. Thus, it is important to consult your physician with any hindering pain you experience, and the same applies for pain that you suspect is spasticity. Remember an official diagnosis is the first step forward, and staying informed on the multiple options available to you is a mile-long leap.