Orthopedic surgery has played an important role in the development of the treatment of spasticity. The development of aseptic technique and more reliable anesthesia allowed expansion of surgical options to more complex procedures, including neurectomies, fasciotomies, osteotomies, and arthrodeses. It is stressed the importance of careful preoperative assessments, selection of appropriate operative procedures, and extensive and prolonged postoperative care.
Goals of surgical treatment
The goals of orthopedic surgery in both cerebral palsy and acquired spasticity are to increase mobility, decrease the use of external aids, correct or prevent deformity and ultimately maximize function. Chronic spasticity may lead to fixed soft tissue or bony deformities. When these do not respond to conservative measures such as manual stretch and serial casting, and are of functional significance to the patient, surgical treatment is warranted. Surgery also has a role in the treatment of spasticity in the absence of fixed deformity. A neurectomy can decrease spasticity through interruption of the reflex arc. Procedures that separate the spastic muscle from its insertion or lengthen its tendon can eliminate its action on the limb or reduce its mechanical advantage. Furthermore, such procedures may, by reducing the stretch on the muscle, decrease the spindle afferent impulses and the resulting spasticity. The specific techniques include tendon lengthening, tendon transfer, neurectomy, osteotomy, resection arthroplasty, and arthrodeses. Joint realignment (osteotomy) and resection or fusion (arthrodeses) is required when joint or bony deformity has developed. Tendon lengthening is used to rebalance agonist-antagonist muscle groups, or correct musculotendinous unit contractures. Tendon transfers have limited indications because of the difficulty in assessing the strength and volitional control of spastic muscles. The joint that is be mobilized by the tendon transfer should have a full passive range of motion preoperatively to maximize the success of the procedure. Neurectomies are mostly limited to the hip (anterior obturator neurectomy) or nonfunctional limbs because an irreparable lesion is created.
The following guidelines maximize the benefit from surgery.
- For procedures requiring active therapy postoperatively, the patient should be developmentally or cognitively at a level to allow adequate cooperation.
- For procedures intended to improve gait, the patient should demonstrate enough trunk control to stand with minimal assistance. Deformities alone do not usually prevent walking.
- Compliance with a preoperative program of exercises and night splinting minimizes the chance of recurrence.
- A stable supportive home or institutional setting should be present to ensure proper postoperative care and follow-up
Although most commonly used with children with CP, the procedures can be applied to children and adult with acquired spasticity as well. The specific cause of the CNS pathology is not often directly relevant to the selection of treatment. The cause, however, may be informative about a number of issues that play a role in treatment planning:
- Is the CNS pathology static / progressive? The answer will clarify the functional prognosis both with and without intervention, and assist in the appropriate timing of surgery.
- Is the patient developmentally or cognitively able to cooperate and participate in pre- and postoperative treatment regimens?
Are developmental changes to be expected that may influence the success and timing of surgery? (Examples are bone growth and maturation of the hip joint.)
There are a number of approaches available in Orthopedic Surgery such as