Feasibility and effectiveness of a newly modified protocol-guided selective dorsal rhizotomy via single-level approach to treat spastic hemiplegia in pediatric cases with cerebral palsy

A preliminary study on the spasticity reduction of quadriceps after selective dorsal rhizotomy in pediatric cases of spastic cerebral palsy

OBJECTIVE

This study aimed to evaluate the potential alleviation of quadriceps spasticity in children diagnosed with spastic cerebral palsy (CP) following selective dorsal rhizotomy (SDR).

METHODS

A retrospective study was conducted on children suffering from spastic CP who underwent SDR at the Department of Neurosurgery, Shanghai Children's Hospital, from July 2018 to September 2020. Inclusion criteria comprised children exhibiting quadriceps spasticity exceeding modified Ashworth Scale grade 2. Muscle tone and motor function were assessed before the operation, at short-term follow-up and at the last follow-up after SDR. Additionally, intraoperative neurophysiological monitoring data were reviewed.

RESULTS

The study comprised 20 eligible cases, where, prior to surgery, 35 quadriceps muscles exhibited spasticity exceeding modified Ashworth Scale grade 2. Following short-term and mid-term follow-up, specifically an average duration of 11 ± 2 days and 1511 ± 210 days after SDR, it was observed that muscle tension in adductors, hamstrings, gastrocnemius, and soleus decreased significantly. This reduction was accompanied by a decrease in quadriceps muscle tone in 24 out of 35 muscles (68.6%). Furthermore, the study found that intraoperative electrophysiological parameters can predict postoperative spasticity relief in the quadriceps. The triggered electromyographic (EMG) output of the transected sensory root/rootlets after single-pulse stimulation revealed that the higher the EMG amplitudes in quadriceps, the greater the likelihood of postoperative decrease in quadriceps muscle tension.

CONCLUSIONS

SDR demonstrates the potential to reduce muscle spasticity in lower extremities in children diagnosed with CP, including a notable impact on quadriceps spasticity even they are not targeted in SDR. The utilization of intraoperative neurophysiological monitoring data enhances the predictability of quadriceps spasticity reduction following SDR.

The discrepancy in triggered electromyography responses between fatty filum and normal filum terminale

BACKGROUND

Functional role of filum terminale (FT) was not well studied though it contains structure basis for nerve impulse conduction. We aimed to explore the possible functions of the FT from the perspective of triggered electromyography (EMG) during surgery.

METHODS

We retrospectively reviewed intraoperative neurophysiological monitoring data from pediatric patients who underwent intradural surgeries at the lumbar level in Shanghai Children's. Hospital from January 2018 to March 2023. Altogether 168 cases with complete intraoperative neurophysiological recordings of the FT were selected for further analysis. Triggered EMG recordings of the filum originated from two main types of surgeries: selective dorsal rhizotomy (SDR) and fatty filum transection.

RESULTS

96 cases underwent SDR and 72 cases underwent fatty filum transection. Electrical stimulation of the FT with fatty infiltration did not elicit electromyographic activity in the monitored muscles with the maximum stimulus intensity of 4.0 mA, while the average threshold for FT with normal appearance was 0.68 mA, and 89 out of 91 FT could elicit electromyographic responses in monitored channels. The threshold ratio of filum to motor nerve roots at the same surgical segment was significantly higher in patients with fatty filum, and a cut-off point of 21.03 yielded an area under curve of 0.943, with 100% sensitivity and 85.71% specificity.

CONCLUSION

Filum with normal appearance can elicit electromyographic activity in the lower limbs/anal sphincter similar to the performance of the cauda equina nerve roots. The threshold of fatty filum is different from that of normal appearing FT. Triggered EMG plays an important role in untethering surgeries.

Modified Selective Dorsal Rhizotomy Exposure Method for Adults With Spastic Paralysis of the Lower Limbs

BACKGROUND AND OBJECTIVES

Spinal deformities are a common complication after selective dorsal rhizotomy (SDR). In this article, we introduce a more minimally invasive SDR procedure in adult patients with spastic paralysis of the lower limbs.

METHODS

In this retrospective analysis of SDR in 8 adult patients with spastic paralysis of the lower limbs, a modified exposure method was used during the surgery. Only the lower part of the L1 spinous process, upper part of the L2 spinous process, and part of the lamina were resected through L1-2 interlaminar approaches. The motor and sensory roots were found to be completely dependent on electrophysiological monitoring. The sensory roots of the target muscle groups were partially transected. All patients were followed up for 2-4 years. The degree of lower extremity spasm was assessed using the Gross Motor Function Classification Scale, Ashworth grading, Gross Motor Function Measure-66, joint range of motion, and electromyography analysis.

RESULTS

All 8 patients were successfully operated with the help of intraoperative electrophysiological monitoring. The Ashworth score of the target muscles, Gross Motor Function Measure-66 score, and range of motion of the joints improved significantly after surgery. Two patients achieved cross-grade improvement in their Gross Motor Function Classification Scale scores. No persistent incision pain or spinal deformities were observed during follow-up.

CONCLUSION

The interspinous process approach provides sufficient surgical space and reduced the damage to the bone structure of the spine. The electrophysiological monitoring protocol is suitable for adult patients with lower extremity spasm.

Unsupervised machine learning effectively clusters pediatric spastic cerebral palsy patients for determination of optimal responders to selective dorsal rhizotomy

Selective dorsal rhizotomy (SDR) can reduce the spasticity in patients with spastic cerebral palsy (SCP) and thus improve the motor function in these patients, but different levels of improvement in motor function were observed among patients after SDR. The aim of the present study was to subgroup patients and to predict the possible outcome of SDR based on the pre-operational parameters. A hundred and thirty-five pediatric patients diagnosed with SCP who underwent SDR from January 2015 to January 2021 were retrospectively reviewed. Spasticity of lower limbs, the number of target muscles, motor functions, and other clinical parameters were used as input variables for unsupervised machine learning to cluster all included patients. The postoperative motor function change is used to assess the clinical significance of clustering. After the SDR procedure, the spasticity of muscles in all patients was reduced significantly, and the motor function was promoted significantly at the follow-up duration. All patients were categorized into three subgroups by both hierarchical and K-means clustering methods. The three subgroups showed significantly different clinical characteristics except for the age at surgery, and the post-operational motor function change at the last follow-up in these three clusters was different. Three subgroups clustered by two methods could be identified as "best responders", "good responders" and "moderate responders" based on the increasement of motor function after SDR. Clustering results achieved by hierarchical and K-means algorithms showed high consistency in subgrouping the whole group of patients. These results indicated that SDR could relieve the spasticity and promote the motor function of patients with SCP. Unsupervised machine learning methods can effectively and accurately cluster patients into different subgroups suffering from SCP based on pre-operative characteristics. Machine learning can be used for the determination of optimal responders for SDR surgery.

Quantitative identification of ventral/dorsal nerves through intraoperative neurophysiological monitoring by supervised machine learning

Objective

This study aimed to investigate the electro-neurophysiological characteristics of the ventral and dorsal nerves at the L2 segment in a quantitative manner.

Methods

Medical records of consecutive patients who underwent single-level approach selective dorsal rhizotomy (SDR) from June 2019 to January 2022 were retrospectively reviewed. Intraoperative electro-neurophysiological data were analyzed.

Results

A total of 74 males and 27 females were included in the current study with a mean age of 6.2 years old. Quadriceps and adductors were two main muscle groups innervated by L2 nerve roots in both ventral and dorsal nerve roots. Dorsal roots have a higher threshold than that of the ventral ones, and muscles that first reached 200 µV innervated by dorsal roots have longer latency and smaller compound muscle action potential (CMAP) than those of the ventral ones. Supervised machine learning can efficiently distinguish ventral/dorsal roots using threshold + latency or threshold + CMAP as predictors.

Conclusion

Electro-neurophysiological parameters could be used to efficiently differentiate ventral/dorsal fibers during SDR.

A systematic review of complications following selective dorsal rhizotomy in cerebral palsy

PURPOSE

The literature lacks a concise overview of complications secondary to selective dorsal rhizotomy (SDR). The aim of this study was to systematically review the literature regarding post-SDR complications, and to present them concisely.

METHODS

The protocol of the review was registered on Open Science Framework. Studies on SDR in cerebral palsy were included. The studies to be included used SDR for management of spasticity in patients with cerebral palsy. The long-term complications of SDR mentioned in the articles were inventoried.

RESULTS

Thirty studies were included for qualitative review. Twenty-one types of complication were identified. Structural complications were the commonest: scoliosis (214/1,043, 20.5%), hyperlordosis (101/552, 18.2%), spondylolysis (55/574, 9.5%) and kyphosis (67/797, 8.4%). Neurological complications comprised constipation (70/485, 14.4%), hip subluxation (3/29, 10.3%), spastic syndrome (4/47, 8.5%), sensory changes (106/1290, 8.2%) and urinary incontinence (61/1013, 6%).

CONCLUSION

This review should help surgeons and parents alike to know about the potential complications of SDR. Complications may affect quality of life and should be weighed. Although the majority of these complications were managed conservatively, there would still be a physical, psychological and financial burden which should be taken into account. Screening should be continued vigorously throughout skeletal growth and at reduced frequency thereafter, for timely intervention in case of structural complications.

Muscle Energy Technique plus Neurac Method in Stroke Patients with Hemiplegia Complicated by Diabetes Mellitus and Assessment of Quality of Life

Objective

To analyze the role of muscle energy technique (MET) plus Neurac method in stroke patients with hemiplegia complicated by diabetes mellitus and the impact on quality of life.

Methods

From January 2021 to December 2021, 100 stroke patients with hemiplegia complicated by diabetes mellitus treated in our institution and assessed for eligibility were recruited and randomly assigned (1 : 3) via the random sampling method to either the conventional rehabilitation group or the experimental group. The patients in the experimental group were randomized (1 : 1 : 1) into either the MET group (receives MET), the Neurac group (receives Neurac), or the joint group (receives MET plus Neurac). The primary endpoint is the clinical efficacy, and the second endpoint is the quality of life.

Results

The eligible patients had similar pretreatment Barthel index scores, Visual Analogue Scale (VAS) scores, Berg balance scale (BBS) scores, Tinetti scores, Fugl-Meyer scores, and quality of life (QoL) scores (P > 0.05). The treatment herein achieved significant improvements in Barthel index scores, VAS scores (2.71 ± 0.28), BBS scores, Tinetti scores, Fugl-Meyer scores, and QoL scores (99.67 ± 10.62), and MET plus Neurac method obtained the best results versus both the conventional rehabilitation and monotherapy of either MET or Neurac (P < 0.05).

Conclusion

Neurac method plus MET improves the independent mobility of stroke patients with hemiplegia and diabetes, relieves pain, enhances balance and stability, mitigates limb dysfunction, and boosts patients' quality of life, so it is worthy of clinical application.

Urodynamic study findings and related influential factors in pediatric spastic cerebral palsy

To investigate the urodynamic study (UDS) result in pediatric patients suffering from spastic cerebral palsy (CP). Medical records of patients diagnosed CP having pre-operative UDS results underwent selective dorsal rhizotomy (SDR) from Jan. 2020 to May. 2021 were retrospectively reviewed. Fifty-seven cases diagnosed spastic CP were included in the study (mean age, 6.73 ± 2.84 years), among which, 46 were ambulatory and 11 non-ambulatory. Average gross motor function measure-66 (GMFM-66) score was 62.16 ± 11.39. Reduced bladder capacity was seen in 49.12% of these cases and cases with lower GMFM-66 score possessed a higher incidence rate of having low bladder capacity (p < 0.01). Detrusor overactivity (DO) was shown in 33.33% of the patients. Cases with younger age presented a higher prevalence of DO (p < 0.05). Meanwhile, more non-ambulant patients suffered from DO (p < 0.05). Increased post-voiding residual (PVR) was seen in 21.05% of the cases. Those with higher average threshold in sphincter-associated input spinal nerve roots (rootlets) witnessed a higher rate of having abnormal PVR (p < 0.05). Abnormal UDS results were prevalent in pediatric patients suffering from CP. Motor function, age and threshold of their sphincter-associated spinal nerve roots laid corresponding effect on the abnormal UDS results.

Improvement of the gait pattern after selective dorsal rhizotomy derives from changes of kinematic parameters in the sagittal plane

OBJECTIVE

Selective dorsal rhizotomy (SDR) can decrease spasticity in children suffering from spastic cerebral palsy (SCP) and thus improve their moving ability when supplemented with the post-operational rehabilitation program. In this case, the study aims to investigate the gait changes in children with mild SCP after SDR in short-term follow-up.

METHODS

The information of ambulatory SCP cases who underwent SDR in our center was retrospectively reviewed, and comparisons of changes in spasticity, motor function and data of gait analysis before and after SDR were analyzed.

RESULTS

In total, 32 cases were included in this study, with a mean age of 5.9 ± 2.1 years old. Noticeable decrease was found in the median value of the pre-operational MAS score after SDR at last follow-up in both sides of adductors, gastrocnemius, soleus, and left hamstrings. The Gross Motor Function Measure-66 score increased from 70.6 ± 9.2 to 73.4 ± 8.2, and the gait deviation index increased after SDR compared with the pre-operational data (right side: 65.8 ± 8.8 vs. 60.1 ± 10.7; left side: 63.5 ± 10.1 vs. 57.0 ± 9.9). Noticeable changes were found that the maximum angle of affected ankles in the sagittal plane (the dorsal-flexion angle) increased from 2.5° to 8.2°, the angles at initial contact (1% gait cycle) of affected knees in the sagittal plane decreased from 34.0° to 27.8°, and the angles at the end of swing phase (100% gait cycle) of affected knees in the sagittal plane decreased from 35.8° to 28.3°.

CONCLUSION

In short-term follow-up, SDR can lower spasticity in children with SCP. Post-operational gait analysis showed improvements in gross motor function and gait, which derived from the changes in the sagittal plane (ankle and knee). A longer follow-up duration is thus needed to clarify the long-term outcome.

Evaluation of Multilevel Surgeries in Children With Spastic Cerebral Palsy Based on Surface Electromyography

The root mean square (RMS) of the surface electromyography (sEMG) signal can respond to neuromuscular function, which displays a positive correlation with muscle force and muscle tension under positive and passive conditions, respectively. The purpose of this study was to investigate the changes in muscle force and tension after multilevel surgical treatments, functional selective posterior rhizotomy (FSPR) and tibial anterior muscle transfer surgery, and evaluate their clinical effect in children with spastic cerebral palsy (SCP) during walking. Children with diplegia (n = 13) and hemiplegia (n = 3) with ages from 4 to 18 years participated in this study. They were requested to walk barefoot at a self-selected speed on a 15-m-long lane. The patient's joints' range of motion (ROM) and sEMG signal of six major muscles were assessed before and after the multilevel surgeries. The gait cycle was divided into seven phases, and muscle activation state can be divided into positive and passive conditions during gait cycle. For each phase, the RMS of the sEMG signal amplitude was calculated and also normalized by a linear envelope (10-ms running RMS window). The muscle tension of the gastrocnemius decreased significantly during the loading response, initial swing, and terminal swing (p < 0.05), which helped the knee joint to get the maximum extension when the heel is on the ground and made the heel land smoothly. The muscle force of the gastrocnemius increased significantly (p < 0.05) during the mid-stance, terminal stance, and pre-swing, which could generate the driving force for the human body to move forward. The muscle tension of the biceps femoris and semitendinosus decreased significantly (p < 0.05) during the terminal stance, pre-swing, and initial swing. The decreased muscle tension could relieve the burden of the knee flexion when the knee joint was passively flexed. At the terminal swing, the muscle force of the tibial anterior increased significantly (p < 0.05), which could improve the ankle dorsiflexion ability and prevent foot drop and push forward. Thus, the neuromuscular function of cerebral palsy during walking can be evaluated by the muscle activation state and the RMS of the sEMG signal, which showed that multilevel surgical treatments are feasible and effective to treat SCP.

The selective dorsal rhizotomy technique for spasticity in 2020: a review

This review looks at the advances in the surgical technique, selective dorsal rhizotomy, used for the management of spasticity in children.

The role of intra-operative neuroelectrophysiological monitoring in single-level approach selective dorsal rhizotomy

OBJECTIVE

Selective dorsal rhizotomy via a single-level approach (SL-SDR) to treat spasticity 100% relies on the interpretation of results from the intra-operative neuroelectrophysiological monitoring. The current study is to investigate the role EMG interpretation plays during SL-SDR procedure with regard to the selection of nerve rootlets for partially sectioning in pediatric cases with spastic cerebral palsy (CP).

METHODS

A retrospective study was conducted in pediatric patients with spastic CP undergone our modified rhizotomy protocol-guided SL-SDR from May 2016 to Mar. 2019 in our hospital. Our study focused on intra-operative EMG interpretation and its correlation with pre-op evaluation results, and dorsal rootlet selection difference when data of our intra-operative EMG recordings interpreted using different rhizotomy protocols.

RESULTS

Clinical and intra-operative neuroelectrophysiological monitoring data of a total of 318 consecutive cases were reviewed, which include 231 boys and 87 girls with 32 hemiplegias, 161 diplegias, and 125 quadriplegias. Age at the time of SL-SDR in those cases was between 3.0-14.0 (5.9 ± 1.9) years. The number of targeted muscle ranged from 2 to 8 over these cases (the muscle in lower limbs with its pre-op muscle tone ≥ 2 grade, Modified Ashworth scale). Among 21,728 nerve rootlets tested (68.3 ± 8.2/case), 6272 (28.9%) were identified sphincter related by our intra-operative neuromonitoring. In the rest of 15,456 (48.6 ± 7.6/case) nerve rootlets which neuromonitoring suggested associated with lower limbs, 11,009 were taken as the dorsal ones (34.6 ± 7.4/case). A total of 3370 (10.6 ± 4.7/case) rootlets matched our rhizotomy criteria with 3061 (9.6 ± 4.1/case) sectioned 50% and 309 (1.0 ± 1.0/case) cut 75%. The rhizotomy ratio (partially transected nerve rootlets/all dorsal rootlets associated with lower limbs in a particular case) was 15.8%, 22.3%, 33.4%, 41.8%, and 45.7% across cases with their pro-op GMFCS level from I to V, respectively. Rootlets required 75% cut had a tendency to increase as well in our cases with their pro-op GMFCS level from I to V, which comprising 1.5%, 4.8%, 8.5%, 14.1%, and 15.2% of all rootlets transected, respectively. The muscle tone of 2068 targeted muscles in these cases at the time of 3 weeks after the SL-SDR was revealed a significant decrease when compared to pre-op (1.7 ± 0.5 vs. 2.7 ± 0.6). Further investigation to compare our rootlet selection with the one guided by the traditional rhizotomy criteria using our intro-operative EMG recordings in 318 cases, revealed that the overlap ratio had a tendency to increase in cases when their pre-op GMFCS level increased (39.5%, 41.3%, 52.2%, 54.1%, and 62.8% in cases with levels I-V, respectively). While our modified rhizotomy protocol successfully identified 2-23 rootlets for sectioning in all of our 318 cases, the traditional rhizotomy protocol failed to distinguish any for cutting in about 20% of cases with their pre-op GMFCS levels I and II.

CONCLUSIONS

The rhizotomy criteria fully rely on the EMG interpretation making intra-operative neuroelectrophysiological monitoring crucial when SDR is performed via a single-level approach. Our modified rhizotomy protocol is feasible, safe, and effective to guide SL-SDR to treat all types of spastic CP cases by decreasing muscle tone in particular spastic muscle groups in their lower limbs. Data of EMG responses during SL-SDR procedure and as well as the clinical outcomes based on their interpretation could help clinicians to further understand how neuronal circuits work in the spinal cord of these patients.

Intraoperative neurophysiological monitoring in selective dorsal rhizotomy (SDR)

For decades, intraoperative neurophysiological monitoring (IONM) has been used to guide selective dorsal rhizotomy (SDR) for the treatment of spastic cerebral palsy (CP). Electromyography (EMG) interpretation methods, which are the core of IONM, have never been fully discussed and addressed, and their importance and necessity in SDR have been questioned for years. However, outcomes of CP patients who have undergone IONM-guided SDR have been favorable, and surgery-related complications are extremely minimal. In this paper, we review the history of evolving EMG interpretation methods as well as their neuroelectrophysiological basis.

Whether the newly modified rhizotomy protocol is applicable to guide single-level approach SDR to treat spastic quadriplegia and diplegia in pediatric patients with cerebral palsy?

PURPOSE

Our aim was to test whether the newly modified rhizotomy protocol which could be effectively used to guide single-level approach selective dorsal rhizotomy (SL-SDR) to treat spastic hemiplegic cases by mainly releasing those spastic muscles (target muscles) marked pre-operatively in their lower limbs was still applicable in spastic quadriplegic or diplegic cerebral palsy (CP) cases in pediatric population.

METHODS

In the current study, we retrospectively conducted a cohort review of cases younger than 14 years of age diagnosed with spastic quadriplegic or diplegic CP who undergone our modified protocol-guided SL-SDR in the Department of Neurosurgery, Children's Hospital of Shanghai since July 2016 to November 2017 with at least 12 months post-op intensive rehabilitation program (pre-op GMFCS level-based). Clinical data including demographics, intra-operative EMG responses interpretation, and relevant assessment of included cases were taken from the database. Inclusion and exclusion criteria were set for the selection of patients in the current study. Muscle tone (modified Ashworth scale) and strength of those spastic muscles (muscle strength grading scale), range of motion (ROM) of those joints involved, the level of Gross Motor Function Classification System (GMFCS), and Gross Motor Function Measure 66 items (GMFM-66) score of those cases were our focus.

RESULTS

A total of 86 eligible cases were included in our study (62 boys). Among these patients, 61.6% were quadriplegic. Pre-operatively, almost 2/3 of our cases were with GMFCS levels II and III. Mean age at the time of surgery in these cases was 6.2 (3.5-12) years. Pre-op assessment marked 582 target muscles in these patients. Numbers of nerve rootlets tested during SDR procedure were between 52 and 84 across our cases, with a mean of 66.5 ± 6.7/case. Among those tested (5721 in 86 cases), 47.9% (2740) were identified as lower limb-related sensory rootlets. Our protocol successfully differentiated sensory rootlets which were considered to be associated with spasticity of target muscles across all our 86 cases (ranged from 3 to 21). Based on our protocol, 871 dorsal nerve rootlets were sectioned 50%, and 78 were cut 75%. Muscle tone of those target muscles reduced significantly right after SL-SDR procedure (3 weeks post- vs. pre-op, 1.7 ± 0.5 vs. 2.6 ± 0.7). After an intensive rehabilitation program for 19.9 ± 6.0 months, muscle tone continued to decrease to 1.4 ± 0.5. With the reduction of muscle tone, strength of those target muscles in our cases improved dramatically with statistical significance achieved (3.9 ± 1.0 at the time of last follow-up vs. 3.3 ± 0.8 pre-op), and as well as ROM. Increase in GMFCS level and GMFM-66 score was observed at the time of last follow-up with a mean of 0.4 ± 0.6 and 6.1 ± 3.2, respectively, when compared with that at pre-op. In 81 cases with their pre-op GMFCS levels II to V, 27 (33.3%) presented improvement with regard to GMFCS level upgrade, among which 4 (4.9%) even upgraded over 2 levels. Better results with regard to upgrading in level of GMFCS were observed in cases with pre-op levels II and III when compared with those with levels IV and V (24/57 vs. 3/24). Upgrading percentage in cases younger than 6 years at surgery was significantly greater than in those older (23/56 vs. 4/25). Cases with their pre-op GMFM-66 score ≥ 50 had greater score increase of GMFM-66 when compared with those less (7.1 ± 3.4 vs. 5.1 ± 2.8). In the meanwhile, better score improvement was revealed in cases when SDR performed at younger age (6.9 ± 3.3 in case ≤ 6 years vs. 4.7 ± 2.7 in case > 6 years). No permanent surgery-related complications were recorded in the current study.

CONCLUSION

SL-SDR when guided by our newly modified rhizotomy protocol was still feasible to treat pediatric CP cases with spastic quadriplegia and diplegia. Cases in this condition could benefit from such a procedure when followed by our intensive rehabilitation program with regard to their motor function.

Surgical Tone Reduction in Cerebral Palsy

This article overviews the surgical options for hypertonia management in cerebral palsy, both spasticity and dystonia. We review the history and use of intrathecal baclofen. We contrast its use with the indications for selective dorsal rhizotomy and review how it is the optimal technique to lower tone in the ambulatory spastic diplegic patient with cerebral palsy. This article reviews the advent of deep brain stimulation, with an emphasis on selection criteria and expected outcomes in this population. The article reviews the principles and use of selective peripheral neurotomy as it is applied to focal spasticity not requiring systemic tone reduction.