Presentation of Spasticity to be Managed by Selective Dorsal Rhizotomy in Children

History

• Prematurity is key: In the long-term experience by the Cape Town group, the children who do best with SDR are those who were born prematurely and are diplegic, have no dystonia and have good antigravity strength prior to surgery (26). One should be suspicious and do thorough investigations for the child with spasticity who was born at full-term.
• Problematic delivery and perinatal period: Typically, there is a history of difficult pregnancy and premature delivery with associated difficulties during the perinatal course such as prolonged respiratory support, possible intraventricular hemorrhage, and possible hydrocephalus, all of which are predictive of possible perioperative management difficulties.
• Delayed motor development: Developmental histories for children responding well to SDR show they did not reach motor milestones at the appropriate age.  They were also late in demonstrating head control and sitting ability as well as balance. They typically became mobile using  commando crawling long before moving to “bunny hopping” or reciprocal crawling because of their initial hypotonia.

Symptoms and signs

Given the diversity of etiologies of CP and the multitude of cerebral territories that can be injured, the ensuing motor syndromes may be highly variable.

• Muscle tone increased because of spasticity: The candidate for a SDR will, as early as age 2.5 to 3 years, have spinal reflexes that are increased. The predominant features in their examination are a velocity-dependent increase in muscle tone, hyperreflexia, and clonus.
• Imbalance in unsupported sitting and standing: Families report frequent falls because of improper posture and a certain degree of ataxia. An ataxic form of CP occurs in approximately 10% of children. Such children have difficulty even with short sitting  because of poor balance. They demonstrate incoordination, intention tremor, and dysdiadokokinesis. The may also have a history of hydrocephalus. In such children, the ataxia is so dominant that alleviation of the spasticity will not lead to improved gait.
• Function impaired by hypertonia: The children have limited sitting ability, poor protective responses, and very little isolation of movements in the lower extremities. These impairments lead to ambulatory difficulties due to a  scissoring gait and equinovarus deformity. Motor impairments far exceed the intellectual difficulties.

Evaluation at Presentation

The treatment of problematic hypertonia in children with CP is elective and typically is being requested to address its interference with effective physical and occupational therapy in a child who is not meeting expectations in his or her motor development.

• Obtain a thorough history and examination: It is important to emphasize that the information gained from the preoperative evaluation is a key factor in successfully reaching the goals of surgery for spasticity.  Function should be the focus of the assessment of candidates for a SDR with their assessment aimed at determining the functional impairment.
• Obtain family’s impressions of child and goals: To avoid postoperative disappointment and resentment, it is key to discuss with the family their perceptions of their child’s abilities and limitations. Their goals for the surgery need to be explored in depth, and this is best done repeatedly to minimize the chance that unstated unrealistic impressions of the child’s capabilities and potential for motor function are present.
• Obtain impression of treating therapist: The problem the child is being referred for is elimination of hypertonia that is blocking anticipated improvement of motor function from physical and occupational therapy. Consequently, a discussion with the treating therapist(s) can be quite helpful for avoiding postoperative disappointment that might results if desired gains by referring health care professionals are not fulfilled

Intervention at Presentation

Preparation for definitive intervention, nonemergent

• X-rays: Spine x-rays are done to identify the presence of spina bifida occulta.
• Urological Consultation: Children with CP can have abnormal urologic function (history of repeated urinary tract infections, delay in toilet training, etc.) (39). A urology consult can be considered along with possible urodynamics evaluation to identify occult urological dysfunction. It is important that this is quantified clinically or objectively prior to surgery and discussed with the family as part of the preoperative consent process.
  Orthotics and adapted seating: Orthotic and other adaptive postoperative needs for a child undergoing a rhizotomy should be anticipated. In some cases, orthotics can be fabricated before surgery. This may also be the case for adaptive seating that will be required during the initial postoperative recovery and therapy periods that can extend for 4 or more months.
• Botox: Selectively targeted Botox injections can play a vital role in functional assessment. By selective reducing spasticity in key muscle groups, such as the hip adductors, for a period of up to six months, the surgeon can gain valuable information about what can be expected after SDR targeted at the same segment.  This can also “buy time” if for some reason the appropriateness of undergoing SDR is best delayed.

Admission Orders

• Routine preparation for major surgery: Patients are admitted the day of the surgery. They should be fasting and should have had informed consent. wCross match and coagulation profile can also be done if part of the hospital’s preoperative protocol.
• Protection from risks of reactive airway: Because this “ex-prem” population suffers from reactive airway disease in general, an anesthesia consult may be considered preoperatively.
• Consider spine x-ray: Patients undergoing SDRs can benefit by having a spine x-ray (APand lateral) done before surgery. This is done to assess for possible spina bifida occulta defects and to help confirm the level for surgery if a “cauda equina” approach is to be used.

Preparation for operating room:

Various units have their own protocols of surgical wound infection prevention, such as body washing with an alcohol-based soap preoperatively, etc