Reactive Balance Control Following Selective Dorsal Rhizotomy in Child With Diplegic Cerebral Palsy

ABSTRACT

Cerebral palsy (CP) is the most common motor disability in early childhood characterized by impaired selective motor control. Children with CP often exhibit delayed and disorganized muscle activation in response to external perturbations, resulting in a high incidence of falls and decreased participation in activities compared with their peers. We examined changes in reactive balance control post‐selective dorsal rhizotomy (SDR) in a child with CP in which the major goal of this surgery is to reduce lower extremity spasticity. A 7‐year‐old girl with spastic diplegic CP (Gross Motor Function Classification System II) participated. Along with clinical evaluations, we employed computerized dynamic posturography to quantify changes in reactive balance control post‐SDR, including the Motor Control Test and the Adaptation Test to simulate unexpected perturbations and assess the child's reactive balance control. Post‐surgery evaluations indicated improved symmetry in lower extremity weight bearing, particularly in response to forward perturbations. No falls were observed post‐surgery in conditions that previously caused imbalance. However, the latency response times to perturbations were longer than in typically developing peers, and the child's force to overcome induced sway was larger than her peers. Although SDR effectively decreased spasticity in our participant, it did not address other factors like soft tissue contractures, muscle weakness, and fixed biomechanical alignment constraints that contributed to balance issues in CP. To our knowledge, this is the first work that demonstrates such limitations post‐SDR. The limited tools available to clinicians to assess reactive balance control in children with CP highlight the need for more effective measurements. This case report sheds light on the importance of targeted clinical approaches to enhance reactive balance control post‐SDR.

Summary.

• Selective dorsal rhizotomy can effectively decreased lower extremity spasticity in children with cerebral palsy (CP); however, it may not address other key functional factors contributing to balance control in CP, which leads to the importance of targeted, multispecialty clinical approaches to enhance function and reactive balance post‐surgery.

1. Introduction

The ability to react to unexpected external perturbations requires a high level of coordination between spinal reflexes and timely muscle activity. In children with cerebral palsy (CP), the most frequent cause of motor disability in early childhood [1], this coordination is usually impaired due to the underlying upper motor neuron injury [2]. The subsequent delayed onset of muscle activation and disorganized recruitment patterns contribute to hindered responses to external perturbations, resulting in loss of balance [3]. Daily falls are common, observed in up to 35% of children with CP [4], with the highest rates noted for children with motor function (Gross Motor Function Classification System, GMFCS) level II [5], likely due to the lack of use of assistive devices but increased immersion in walking activities [4]. Unfortunately, the reduced stability during walking [6] and concomitant increased fear of falls are associated with decreased participation in children with CP compared with typically developing peers [7].

Traditionally, a surgical approach utilized to help children with CP improve movement control is the selective dorsal rhizotomy (SDR) procedure. This surgical procedure aims to reduce lower extremity spasticity by surgically interrupting afferent input into the reflex arcs responsible for the increased muscle tone. Following SDR, positive gait outcomes have been reported related to improved kinematics [8] and muscle performance [9]. Additionally, a reduction of center of mass sway during static stance suggests improved control of upright posture [10]. While changes to walking capacity after SDR have been reported, the ability to control reactive balance [11] has been vastly overlooked [12]. To our knowledge, there is a paucity of literature on the short‐term effects of SDR on postural control, particularly the control involving rapid, reactive motor responses that are critical for fall prevention. In this case report, we describe an attempt to quantify changes in reactive balance control following SDR in a child with CP (GMFCS II) utilizing computerized dynamic posturography and clinical evaluations. In addition to the improved motor control about individual lower extremity joints, functional dependence is expected to improve, leading to enhanced participation.

Prior studies have not systematically incorporated objective, perturbation‐based methods to evaluate changes in balance responsiveness following SDR. Our case study is unique in its integration of computerized dynamic posturography with clinical assessments to examine short‐term reactive balance control following SDR in a child with spastic diplegic CP (GMFCS II). By focusing on balance control beyond static measures or voluntary gait parameters, this case aims to highlight specific deficits that may persist despite the surgical reduction of spasticity, informing a more comprehensive post‐SDR rehabilitation framework.

2. Case History/Examination

A 7‐year‐old girl, diagnosed with spastic diplegic CP (GMFCS II), participated in our study. Observationally, at the initial assessment, the child's standing posture was asymmetrical, with greater weight bearing on her right lower extremity. A significant ankle plantar flexion contracture, 50°, prevented her from placing her left heel on the floor. To compensate for this contracture, she demonstrated posturing of her left hip in 20° of flexion and left knee in 40° of flexion while in standing (Figure 1). Muscle tone assessment (modified Ashworth Scale, MAS) indicated an increase in bilateral knee extensors (1+), bilateral ankle plantar flexors (2) on the right, (3) on the left, and in left ankle inverters (1). She was able to maintain static standing for greater than 60 s without support. She did not require physical assistance or a device to walk on level surfaces. Her gait demonstrated asymmetrical weight bearing with decreased weight shifts to the left side. Her left lower extremity remained internally rotated at the hip, with increased knee flexion and equinovarus at her left ankle.

FIGURE 1.

Independent standing posture of child participant during baseline session with noted increased left ankle plantar flexion, hip flexion, and hip internal rotation. Observationally, weight bearing is primarily on the right lower extremity.

3. Methods

3.1. Procedures

Parental informed consent and child assent forms were secured prior to child engagement in research activities in accordance with the World Medical Association Declaration of Helsinki. Our research protocol was approved by the Institutional Review Board at the University of North Florida.

Assessment of reactive postural control was assessed utilizing computerized dynamic posturography (SMART Balance Master/Equitest System, NeuroCom, NatusMedical Inc) [13] and clinically via functional assessment (Kids BESTest) [14]. Assessment used to quantify participation in family and recreational activities was the Child Engagement in Daily Life [15]. Baseline and post‐surgery assessments occurred 105 days apart, with the post‐surgical assessment occurring 8 weeks following surgery.

For the Motor Control Test, three translatory perturbations were administered unexpectedly, per standardized test, either to the anterior or posterior direction at three amplitudes (small, medium, and large translations) scaled to the child's height. For the Adaptation Test, the platform tilted toes up 5 times and toes down 5 times over a 2–5 s time without the patient's knowledge of when rotations would take place. For the Kids‐BESTest, all tasks from each domain were administered utilizing standardized equipment according to established protocols.

The participant underwent SDR without complications. She was hospitalized for 3 days following the surgery, then discharged home. Five days following the surgery, the child began intensive outpatient physical therapy services, attending 60‐min sessions 4 days/week. Both pre‐ and post‐surgical evaluations were conducted at the University of North Florida's Laboratory of Applied Biomechanics and Engineering by a pediatric physical therapist with over 30 years of experience. The child was accompanied by her parents during both sessions.

3.2. Data Analysis

A descriptive statistical approach was used to describe pre‐post data of this single case report. For comparative purposes [10], average data from typically developing (TD) peers were included. These TD values were obtained from previously published normative datasets using the same computerized dynamic posturography protocols and equipment [16, 17]. These references demonstrate established benchmarks for TD children for weight symmetry, latency, and sway energy scores for age‐matched children without neurological impairments.

4. Results

Post‐surgery, improvement of passive range of motion in bilateral ankles was noted. Her right and left ankle dorsiflexion improved to 20° and 0°, respectively, with her knees extended, and to 25° and 5°, respectively, with her knees flexed. Manual muscle testing graded was unchanged. Assessment of tone (MAS) demonstrated no spasticity in her lower extremities (0/4 throughout). Observationally, during static standing, the child's right foot remained flat on the floor; despite the absence of abnormal muscle tone as well as an improvement in the passive range of motion of left ankle dorsiflexion, her left lower extremity remained flexed at her hip and knee, internally rotated at her hip, and plantar flexed at the foot (Figure 2).

FIGURE 2.

Child performing computerized dynamic posturography during post‐surgery assessment. Observationally, weight bearing is primarily on the right lower extremity, similarly to the posture during the initial assessment.

The Motor Control Test weight symmetry prior to the surgery demonstrated increased weight bearing on the right lower extremity under all conditions. Following the surgery, preference to bear most weight on the right lower extremity remained when the platform moved backward, eliciting a forward perturbation. However, when the platform moved forward, eliciting a backward perturbation, the child demonstrated improved symmetry of lower extremity weight bearing. Pre‐surgery, a small forward perturbation caused her to lose her balance, and following surgery, she did not demonstrate any falls. Latency response times to all perturbations, both in direction and in amplitude, increased following surgery and were longer than reported TD peers. On the adaptation test, average SES following surgery increased when her toes were tipped up and decreased when her toes were tipped down (Table 1). Both pre‐ and post‐surgery, the child's magnitude of force to overcome the induced sway induced by the platform rotations was larger than TD peers. On the Kids BESTest, although improvements were observed in all sections but one, only Biomechanical Constraints and Stability in Gait surpassed established SDC. Overall, the total score improved from baseline to post‐surgery (41–56), surpassing the SDC of 5.6 points for children with CP. On the Child Engagement of Daily Life Survey, parents reported changes in participation from baseline (scaled score of 47.4) to post‐surgery (66). This change was also observed for enjoyment, with the scaled score changing from 64.2 to 88.2 (Table 1).

TABLE 1.

Computerized dynamic posturography scores.

Motor Control Test
	Translation amplitude	Weight symmetry (points)		Latency (ms)
				Baseline		Post‐surgery		TD (n = 100) comparison [16]
		Baseline	Post‐surgery	Left	Right	Left	Right
Backward	Small	114	173	Fall	Fall	260	230
	Medium	99	155	0	150	0	290	104 ± 55
	Large	149	164	0	130	0	140
Forward	Small	153	174	0	140	0	160
	Medium	154	128	140	130	190	160	151 ± 34
	Large	150	116	170	110	120	150

Adaptation Test
Toes‐up (SES score)			Toes‐down (SES score)
Baseline	Post‐surgery	TD (n = 52) comparison	Baseline	Post‐surgery	TD (n = 52) comparison [17]
161	181	138 ± 24	177	162	120 ± 27

Note: TD, typically developing; SES, sway energy score representing the magnitude of the force response required to overcome the sway induced by platform rotations; Latency, reaction time between translation onset and initiation of active response to the movement of the surface; Weight symmetry, 0 indicates complete left‐sided use, 100 indicates symmetrical use of both sides, 200 indicates complete right‐sided use.

5. Discussion

While dynamic balance is modulated during walking and turns, the reactive component is crucial to maintaining independence in walking activities. For a child to keep up with family and friends during outings and physical activities, responding to environmental threats to balance, such as slips and trips, must be effective for successful engagement [18]. Since muscle responses to such perturbations require appropriate magnitude, timing, and agonist–antagonist co‐contraction, children with CP may encounter difficulties maintaining their balance, impacting participation and the typical development of quality of life.

Current research indicates that SDR is effective in decreasing spasticity in pediatric patients diagnosed with CP, potentially impacting muscle activation and coordination which, in turn, should influence children's reaction to sudden disturbances or imbalances [19]. Nonetheless, as observed in our current case report, this procedure does not address other complications such as soft tissue contractures, muscle weakness, and fixed biomechanical alignment constraints, which are significant contributors to impaired balance and postural control. The case study we observed involved a participant who exhibited each of these complicating factors, providing a possible rationale for the reason why the SDR procedure did not generate a marked improvement in the child's balance as quantified by computerized dynamic posturography. Moreover, the expected increase in overall functional abilities was also not observed within the immediate timeframe post‐surgery of our research design.

Previous studies have demonstrated that while SDR effectively reduces spasticity, its impact on functional balance control remains variable and often limited by coexisting neuromuscular and biomechanical impairments. For instance, although SDR has been associated with improvements in gait kinematics and reduced muscle tone [20, 21], persistent deficits in postural responses suggest that spasticity is only one component of the broader motor control challenges in CP. Evidence from longitudinal analyses indicates that improvements in gross motor function post‐SDR may plateau or decline without targeted rehabilitation addressing strength, coordination, and balance [22, 23]. Furthermore, studies employing electromyographic and kinematic evaluations have shown that children with CP often exhibit atypical muscle synergies during reactive balance tasks, even after spasticity reduction [24, 25].

Prolonged latency times observed post‐SDR may reflect persistent neuromuscular disorganization, a phenomenon that has been noted in various neurological conditions. In individuals with CP who have undergone SDR, variability in long‐term motor outcomes has been attributed in part to differences in neuromuscular integration and post‐operative rehabilitation, suggesting that some degree of disorganization may persist despite surgical intervention [26]. In peripheral neuropathies, delayed muscle response latencies have been significantly associated with reduced nerve conduction velocities, indicating impaired afferent input and slowed sensorimotor processing [27]. Therapeutically, latency improvements may be targeted through perturbation‐based balance training, task‐specific gait interventions, and neuromuscular electrical stimulation, which have shown promise in enhancing sensorimotor integration and reducing response delays in pediatric and adult populations with neurological impairments [28, 29].

Important to note the restricted access clinicians have to available resources to assess reactive balance control in children with CP. Certain functional improvements following SDR have been reported in children with CP; however, current clinical assessments fall short in quantifying reactive balance performance. Quantifying the control (or lack of thereof) of reactive balance provides clinicians with a tool to determine if the child's motor responses meet actual demands of independent ambulation [30]. Clinical care at this period post‐SDR should potentialize children's outcomes related to navigation in varied environments with altered terrain and surface challenges.

To our knowledge, this is the first report to examine reactive balance control using computerized dynamic posturography at 8 weeks post‐SDR in a child with CP. While most studies focus on long‐term outcomes, this early assessment provides a novel perspective on the immediate neuromuscular and functional changes following surgery. The findings suggest that despite reduced spasticity, impairments in reactive balance may persist due to unresolved biomechanical and neuromuscular factors. Clinicians should consider incorporating targeted interventions for reactive balance early in the post‐operative period to support functional recovery and reduce fall risk.

A primary limitation of this case report is the relatively short follow‐up period of 8 weeks post‐SDR. While most studies assessing functional outcomes after SDR report follow‐up intervals of 6 months [31] to several years [32], allowing time for neuromuscular adaptations to emerge, our early assessment may not fully capture the long‐term trajectory of recovery (e.g., gait, strength, and balance improvements). However, this early post‐operative window offers a novel and clinically relevant perspective. Understanding the timing of initial changes in reactive balance control is critical for informing early rehabilitation strategies and setting realistic expectations for families and clinicians. As a case report, this study provides preliminary evidence that can guide future investigations with larger cohorts and extended follow‐up periods to characterize the timeline and mechanisms of functional recovery post‐SDR.

6. Conclusion

This case study provides insights into the control of reactive balance after a surgical procedure focusing on decreasing lower extremity spasticity that is performed. Clinical approaches targeting lower extremity strengthening, anticipatory balance challenges, and training of responses to external perturbations should be prioritized to maximize outcomes. Given the crucial care provided by pediatric physical therapists following SDR, including rigorous strengthening and gait activities, our findings suggest the initiation of a research agenda focusing on improving reactive balance control post‐SDR to enhance participation and activity engagement for children with CP.

Author Contributions

Debra Depto‐Hoffman: conceptualization, formal analysis, funding acquisition, investigation, methodology, visualization, writing – original draft, writing – review and editing. Ligia Y. Mochida: data curation, formal analysis, methodology, validation, visualization, writing – review and editing. Guilherme M. Cesar: conceptualization, data curation, formal analysis, funding acquisition, investigation, methodology, project administration, writing – original draft, writing – review and editing.

Ethics Statement

The authors declare that appropriate written informed consent was obtained from the patient's parent for the publication of the child's dataset (presented in this manuscript) and accompanying images. The study and consent forms were approved by the Institutional Review Board at the University of North Florida.

Conflicts of Interest

The authors declare no conflicts of interest.

Depto‐Hoffman D., Mochida L. Y., and Cesar G. M., “Reactive Balance Control Following Selective Dorsal Rhizotomy in Child With Diplegic Cerebral Palsy,” Clinical Case Reports 13, no. 10 (2025): e70975, 10.1002/ccr3.70975.

Data Availability Statement

The datasets for this article are not publicly available due to privacy or ethical concerns. Requests to access the datasets should be directed to the corresponding author.