Selective Dorsal Rhizotomy clinical outcomes

Clinical outcomes are measurable changes in health, function or quality of life that result from our care. Constant review of our clinical outcomes establishes standards against which to continuously improve all aspects of our practice.

About the Selective Dorsal Rhizotomy service

GOSH established its Selective Dorsal Rhizotomy (SDR) service in 2013 and is one of five centres providing the service in England. SDR is an operation used to reduce spasticity (muscle stiffness) in children with cerebral palsy.

Spasticity can impair movement and coordination, cause pain, and over time can cause shortening of muscles and tendons, joint contractures and bone deformities. Nerve fibres running from the muscles back to the spinal cord play a major role in spasticity. The SDR operation, in which some of these fibres are divided, can be very effective at reducing spasticity and improving quality of life.

SDR is the only procedure to permanently remove spasticity in the legs of children with cerebral palsy. However, it is not a suitable treatment for every patient, so full assessment and preparation are an essential part of the care we provide.

Clinical outcome measures

Measures of the treatment effectiveness of SDR include surgical and specialist therapy outcomes.

Between 2014 and 2018, a study of 30 patients undergoing SDR recorded clinical outcomes which are reported here.

1. Modified Ashworth Scale (MAS)

The MAS measures resistance during soft-tissue stretching, and is used to assess the effectiveness of treatment to reduce spasticity. We test the lower limbs (adductors, hip flexors, knee flexors and plantar flexion), and they are scored from 0 (normal tone) to 4 (rigid tone). Average scores for all lower limb muscle groups before surgery were between 2 and 4. At two years post-surgery the average score was 0 for 97 per cent of children (n = 29/30) indicating a reduction in spasticity. One child had minimal residual muscle tone in a single muscle group. All 30 children had improvements in MAS scores of one point or more for all muscle groups.

The MAS assessment is completed up to one month prior to surgery, and at six months, one year and two years post-surgery. The average score at each time point is compared to see the early effect of surgery on the child’s spasticity and the effect over time.

The Gross Motor Function Classification System (GMFCS) classifies children’s gross motor function with those at level I having the least functional limitations, and those at level V the greatest functional limitations.

Table 1.1 Average MAS score for leg muscle groups

GMFCS level Pre-surgery Six months post-surgery One year post-surgery Two years post-surgery

GMFCS level II (n = 10)

2.58 0.01 0.04 0.00

GMFCS level III (n = 20)

2.85 0.00 0.00 0.01

The data shows that MAS scores improved after SDR surgery, and the improvement sustained over time.

2. Gross Motor Function Measure (GMFM)

Gross motor skills are involved in the movement, balance and coordination of the body. The GMFM is a standardised assessment tool used by specialist paediatric physiotherapists to evaluate change in gross motor function in children with cerebral palsy. The measure has a 4-point scoring system across the five categories: lying and rolling; sitting; crawling and kneeling; standing; walking, running and jumping. To measure progress after surgical and therapy interventions, we use the GMFM-66, in which a child’s gross motor function is observed and tested against 66 standardised items.

The GMFM-66 assessment is completed pre-surgery, and after surgery at six months, one year and two years post-surgery. The average scores at each time point is compared to see the early effect on of surgery on the child’s gross motor skills and the effect over time.

The average increase in GMFM-66 for children with a GMFCS level II is 5.54 (from 68.16 pre-surgery to 73.69 two years post-surgery). For children with a GMFCS level III the average increase is 5.67 (from 50.56 pre-surgery to 56.27 two years post-surgery).

Figure 1.1 Average GMFM pre- and post-surgery by GMFCS

Figure 2.1 Average GMFM pre- and post-surgery by GMFCS level

The increase in GMFM-66 score for individual children from before surgery to two years post-surgery ranges from 0 to 18.3. While children’s GMFM-66 score generally increases at two years post-surgery, some have moderate improvement or maintained function.

3. Cerebral Palsy Quality of Life (CP QOL-Child)

The CP-QoL is a questionnaire about quality of life for children and young people with cerebral palsy. The questions cover general and social wellbeing, function, physical health, self-esteem, pain, impact of disability, schooling, and family health. We use the primary caregiver questionnaire for all our patients.

The CP-QoL primary caregiver questionnaire is completed pre-surgery, and after surgery at six months, one year and two years post-surgery. An average score is calculated for the seven areas using the answers to individual questions within that area. Scores are based on responses at a specific ‘snapshot’ in time. Below we show the average scores pre-surgery and at two years post-surgery, by GMFCS level.

Table 3.1 Average CP QoL scores pre- and two years post-surgery by GMFCS

GMFCS level Pre-surgery Two years post-surgery
Social wellbeing and acceptance
GMFCS level II (n=10) 73.2

80.0

GMFCS level III (n=20) 74.9 75.2
Feelings about functioning
GMFCS level II (n=10) 67.9 79.7
GMFCS level III (n=20) 65.5 71.1
Participation and physical health
GMFCS level II (n=10) 58.6 67.5
GMFCS level III (n=20) 52.6 56.4
Emotional wellbeing and self-esteem
GMFCS level II (n=10) 67.3 79.0
GMFCS level III (n=20) 75.1 77.9
Access to services
GMFCS level II (n=10) 46.9 51.5
GMFCS level III (n=20) 44.5 44.1
Pain and impact of disability*
GMFCS level II (n=10) 39.2 29.7
GMFCS level III (n=20) 43.7 42.4
Family health
GMFCS level II (n=10) 67.8 84.4
GMFCS level III (n=20) 68.1 68.8

* For ‘pain and impact of disability’ section a lower average score indicates a reduction in pain and impact of disability.

For questions on feelings about functioning; participation and physical health; and emotional wellbeing and self-esteem the average CP-QoL caregiver scores increase between pre-surgery and 2 years post-surgery. For children with a GMFCS level II, the increase in the average score is greater than for children with a GMFCS level III. 

For questions on social wellbeing and acceptance; access to services; and family health the average scores increase for children with a GMFCS level II, but remain stable for children with a GMFCS level III.

The average score for the pain and impact of disability questions decreases (indicates a reduction in pain and impact of disability). Children with a GMFCS level II see a greater decrease than children with a GMFCS level III.

4. Complications of SDR surgery

For all patients undergoing SDR at GOSH we record complications. We are currently working on publishing the full range of measures for all our patients.

Every surgical procedure carries risk. It is essential to collect data on complications or ‘adverse events’ to have an accurate understanding of both risk and surgical performance. This is turn informs the consent process for future patients and their families considering surgery. We collect data on the following complications associated with SDR surgery: surgical site infection (superficial incisional; deep incisional; organ/space); bleeding that requires return to theatre; cerebrospinal fluid (CSF) leak; and permanent incontinence due to surgery.

Table 4.1 Complications of SDR surgery, 2013/14 to 2018/19

    Complications of SDR surgery
Year Total number of operations Infection Bleeding that requires return to theatre CSF leak Permanent incontinence due to surgery
2013/14* 12 0 0 0 0
2014/15 23 1 (superficial) 0 0 0
2015/16 32 0 0 0 0
2016/17 32 0 0 0 0
2017/18 23 0 0 0 0
2018/19 28 0 0 0 0
TOTAL 150 1 0 0 0

*SDR surgery commenced in July 2013, so the 2013/14 figures span nine months.

This information was published in November 2019 and will be updated in November 2020.

References

McLaughlin, J. et al., Selective dorsal rhizotomy: meta-analysis of three randomized controlled trials, Developmental Medicine & Child Neurology, 2002, 44: 17–25.

Engsberg, J.R. et al., Effect of selective dorsal rhizotomy in the treatment of children with cerebral palsy, Journal of Neurosurgery, 2006, 105(1 Supplement): 8–15.

Nordmark, E. et al., Long-term outcomes five years after selective dorsal rhizotomy, BMC Pediatrics, 2008, 8:54.

van Schie, P. E. M. et al., Short- and long-term effects of selective dorsal rhizotomy on gross motor function in ambulatory children with spastic diplegia, Journal of Neurosurgery Pediatrics, 2011, 7:557-562.

Summers, J et al., Selective dorsal rhizotomy in ambulant children with cerebral palsy: an observational cohort study, The Lancet Child & Adolescent Health, 2019, https://doi.org/10.1016/S2352-4642(19)30119-1