Spastic diplegia, historically known as Little's Disease, is a form of cerebral palsy (CP) that is a neuromuscular condition of hypertonia and spasticity in the muscles of the lower extremities of the human body, usually those of the legs, hips and pelvis. Doctor William John Little's first recorded encounter with cerebral palsy is reported to have been among children who displayed signs of spastic diplegia.

This condition is by far the most common type of CP, occurring in almost 70% of all cases.

Background

Spastic diplegia's particular type of brain damage inhibits the proper development of upper motor neuron function, impacting the motor cortex, the basal ganglia and the corticospinal tract. Nerve receptors in the spine leading to affected muscles become unable to properly absorb gamma amino butyric acid, the amino acid that regulates muscle tone. Without GABA absorption to those particular nerve rootlets, affected nerves perpetually fire the message for their corresponding muscles to contract, and the muscles become permanently hypertonic.

This abnormally high muscle tone creates difficulty with voluntary and passive movement, and generally creates stress over time — depending on the severity of the condition in the individual, the constant spasticity ultimately produces pain, muscle/joint breakdown, premature physical exhaustion, contractures, spasms, and progressively worse misalignments of bone structure around areas of the tightened musculature.

The condition is congenital; i.e., it is acquired shortly before or during the birth process. Instances of after-birth causes, such as exposure to toxins, traumatic brain injury, encephalitis, meningitis, drowning or suffocation are minuscule-to-nil by comparison. Periventricular leukomalacia (neonatal asphyxia), hypoxia of the brain, premature birth, birth trauma, hematoma in the brain, or the presence of certain maternal infections during pregnancy can all lead to spastic diplegia.

 

Presentation

The main difference between spastic diplegia and a normal gait pattern is its signature "Scissor gait" — a style that some able-bodied people might tend to confuse with the effects of drunkenness, multiple sclerosis or another nerve disease. The degree of spasticity in spastic diplegia (and, for that matter, other types of spastic CP) varies widely from person to person. No two people with spastic diplegia are exactly alike. Balance problems and/or stiffness in gait can range from barely noticeable all the way to misalignments so pronounced that the person needs crutches or cane to assist in ambulation. Less often, spasticity is severe enough to compel the person to use a wheelchair; in general, however, lower-extremity spasticity in spastic diplegia is rarely so great as to totally prevent ambulation — most people with the condition can walk.

Above the hips, persons with spastic diplegia typically retain normal or near-normal muscle tone and range of motion, though some lesser spasticity may also affect the upper body, such as the trunk and arms, depending on the severity of the condition in the individual. Additionally, because leg tightness often leads to instability in ambulation, extra muscle tension usually develops in the upper body, shoulders, and arms due to compensatory stabilization movements, regardless of the fact that the upper body itself is not directly affected by the condition.

Treatment

As a matter of everyday maintenance, muscle stretching, range of motion exercises, yoga, contact improvisation, modern dance, resistance training, and other physical activity regimens are often utilized by those with spastic CP to help prevent contractures and reduce the severity of symptoms.

Major clinical treatments for spastic diplegia are:

• Baclofen (and its derivatives), a gamma amino butyric acid substitute injected into the spinal fluid for trial, and thereafter administered either orally or via an intrathecal pump;

• Phenol, injected selectively into the over-firing nerves in the legs on the muscle end to reduce spasticity in their corresponding muscles;

• Botox, injected directly into the spastic muscles;

• Orthopedic surgery to release the spastic muscles from their hypertonic state, a usually temporary result because of the source of the spasticity being in the nerves, not the muscles; and,

• Selective Dorsal Rhizotomy, a neurosurgery directly targeting and eliminating ("cutting" or "lesioning") the over-firing nerve rootlets and leaving the properly-firing ones intact, thereby permanently eliminating the spasticity but compelling the person to spend months re-strengthening muscles that will have been severely weakened by the loss of the spasticity.