The central nervous system consists of the brain and spinal cord (within the spine). It may be affected by various conditions, including:

• Stroke (CVA), most often leading to hemiplegia or hemiparesis

• Severe traumatic brain injury, with variable clinical presentations depending on the affected brain areas

• Spinal cord injuries, resulting in complete or incomplete tetraplegia or paraplegia

• Cerebral palsy (formerly referred to as infantile cerebral palsy), due to brain injury occurring before, during, or within the first two years after birth

• Inflammatory diseases, such as multiple sclerosis

• Degenerative disorders, such as parkinsonian syndromes or acquired deforming hypertonia in older adults

• Brain or spinal tumors, and genetically related neurological conditions

Surgery for the sequelae of central neurological disorders—also known as neuro-orthopedics—aims to reduce limb deformities caused by these conditions and, in some cases, improve function.

Surgical indications are assessed on a case-by-case basis due to the wide variability of clinical presentations.

The objectives of the procedure may be hygienic (for example, in cases of permanently clenched hands), functional for dressing (an excessively flexed elbow or wrist may hinder the passage of a sleeve), or aesthetic (reducing the visibility of a deformity that may be perceived as stigmatizing). In some patients, although a normal limb cannot be restored, function can nevertheless be improved.

The indication for surgery is considered only after medical treatment has been undertaken (botulinum toxin injections in cases of muscle hypertonia, physiotherapy including strengthening and stretching). In most cases, the decision to proceed with surgery is made during so-called multidisciplinary consultations, conducted in rehabilitation centers, in collaboration with a physical and rehabilitation medicine physician and teams in physiotherapy and occupational therapy.

A variety of surgical procedures may be used:

• Treatment of muscle hypertonia (for example spasticity occurring in the context of stroke, traumatic brain injury, or cerebral palsy) is performed through a highly specific microsurgical nerve procedure called selective or hyperselective neurectomy. This procedure, mastered by only a limited number of teams in France and worldwide, has the advantage of providing lasting reduction of muscle spasticity without weakening the muscle, unlike other techniques such as tendon lengthening.

• If muscle hypertonia leads over time to tendon retraction (shortening), a tendon or muscle lengthening procedure will be required.

• When functional restoration is feasible, tendon or nerve transfer procedures may be proposed in selected patients to restore movement (for example, wrist extension in brain-injured patients, or hand opening and closing in patients with spinal cord–related tetraplegia).

Depending on the procedure performed, immobilization may be required for several weeks. This is followed by rehabilitation in a specialized center.