In Hong Kong, patients with CP who may benefit from SDR are usually referred to a multidisciplinary clinic for consideration of SDR. Regular team members include Neurosurgeons, Developmental Paediatricians, Orthopaedic Surgeons, Physiotherapists, Kinesiologist and School Therapists. Patients were considered for SDR if they matched the inclusion criteria set by Cole. SDR was performed under general anaesthesia by a single surgeon in a single centre, except for one patient in our cohort. Patients will follow intensive program of physiotherapy in the first 3 months post-surgery. After that, physiotherapy and mobility training is usually carried out by the hospital physiotherapist for patients who studies in Mainstream School and by school physiotherapists for those studies in Physical Handicap School. For the post-operative care, apart from follow up by the hospital team, all patients were followed up by the CAS team regularly until they reached adulthood. For the controls, reasons for not having SDR in the control groups were parental refusal or not matching the Cole’s criteria, that is relatively weak in proximal muscle power, weak in family support and age range outside the inclusion criteria. The controls were all being follow-up regularly in hospital clinic with physiotherapy arrangement similar to the SDR group.
Subjects
This study is a retrospective case control study. Patients with confirmed diagnosis of spastic diplegia with positive birth history or brain imaging evidence who had underwent SDR 6 to 12 years ago were contacted. Those with Gross Motor Function Classification System (GMFCS) levels I to III and with normal or close to normal intelligence were included. Patients with other diagnoses such as hereditary spastic paraparesis or progressive neurological diseases were excluded. Age, gender, range of intelligence quotient and GMFCS level matched individuals with spastic diplegic CP who had not undergone SDR were recruited from Child Assessment Service as controls. (See Table 2)
In total, 37 patients with SDR and 61 patients without SDR (as controls) with age-and-gender matched who met inclusion criteria were contacted. 15 patients with SDR and 12 controls participated in the study.
All participants were invited to perform assessments on three major domains including bodily impairment, physical activity and participation on two separate visits, at least 7 days apart, to prevent physical fatigue that may affect their performance. Demographic data were measured and medical history that may potentially affect the outcomes were recorded. Total number of orthopaedic surgeries performed were also recorded.
Outcome measures
1. Bodily impairment:
All subjects underwent physical examination by doctors and physiotherapists with Paediatric and Physical rehabilitation training. Muscle tone of lower limb muscles was assessed and recorded as Modified Ashworth Scales (MAS) with a score ranged from 0 to 4. [11] Range of motion (ROM) of the joints moved by the above muscles were measured by goniometer. Muscle power was assessed using Medical Research Council on a scale of 0 to 5 (Medical Research Council, 1976). Other information such as presence of scoliosis, hip subluxation and patella alta were documented.
2. Physical activity:
Ambulatory levels of all subjects were documented using GMFCS with levels ranged from I to V [1]. The lower the level, the better functional ability it represents.
Six-minute walk test (6MWT) was used to assess the level of exercise capacity and the level of oxygen consumption was measured. All subjects were asked to walk back and forth along a 30-meter path for 6 minutes following a standardized protocol. [12] The distance walked in 6-minutes (6MWD) was recorded. During the test, each subject was asked to wear a mask which was connected to a breath by breath gas analyzer (Oxycon Mobile, CareFusion, CA, USA) to measure the level of oxygen consumption at rest, that is 5 minutes before, during and 5 minutes after 6MWT.
The walking quality and gait pattern of all subjects was recorded as Edinburgh Visual Gait Score (EVGS). [13] It scores on the position of the trunk, pelvis, hip, knee, ankle and foot during both stance and swing phases of walking. EVGS is a 3-point ordinal scale with a score ranging from 0 to 2 on 17 observations making a maximal summative score of 34. The lower the score, the better the walking quality it indicated.
3. Participation:
Gillette Functional Assessment Questionnaire (Gillette FAQ), either self-rated or parent reported, was used to determine the daily walking ability. The walking aids used were documented.
Quality of life was assessed by Cerebral Palsy Quality of Life Questionnaire-Teen (CPQOL-Teen) [14] which examined the level of quality of life in the domains of general well-being, communication, school well-being, social well-being and feeling of function from the perspective of patients (CPQOL-Teen) and caregivers (CPQOL-Primary Caregiver). The subjects and their parents were asked to fill in CPQoL-Teen (HK) version and CPQOL–Primary Caregiver (HK) version, respectively. [15] The scale ranges from 0 to 100 for each domain specific score.
4. Information on potential complications related to SDR such as pain, spinal deformity and bowel and urinary problem were collected.
5. Parents’ view on the perceived effectiveness and worthiness of SDR for the SDR subjects was collected during follow up.
Statistical analysis
All data were presented as mean ± standard deviation. Categorical data were presented as number (percentage). Continuous data were compared by independent t-test while categorical data were analyzed by chi-square test to detect between-group differences. All statistical analyses were run by IBM SPSS statistical software for windows, version 23 (IBM Corporation, USA).