Neurosurgical applications of the exoscope: from in vitro studies to real-life surgical use in selective dorsal rhizotomy.

BACKGROUND: The microscope has been the gold standard in neurosurgical practice due to its ability to magnify anatomical structures. However, it has limitations, including restricted visual fields and ergonomic challenges that can lead to surgeon fatigue and musculoskeletal issues. The exoscope is an emerging technology that may address these limitations by offering comparable magnification with improved ergonomics. METHODS: This study compares the traditional microscope (KINEVO 900) with a 3D digital exoscope (Aeos Digital Microscope) in visual field width, image sharpness, and ergonomic impact. Visual field assessments were conducted using millimeter paper at a fixed distance, while image sharpness was evaluated using graph paper with pins at different depths. Ergonomic evaluation involved simulating surgical positions using a spine anatomical model. The practical applicability was tested during Selective Dorsal Rhizotomy (SDR) procedures, comparing the surgeon's experience with both devices over 20 consecutive cases. RESULTS: The exoscope provided a larger visual field (81.18 cm2) compared to the microscope's (54.10 cm2). Image sharpness was similar for both devices across various depths and zoom levels. Ergonomically, the exoscope allowed the surgeon to maintain a neutral posture while visualizing extreme angles, unlike the microscope, which required significant upper body movement. In SDR procedures, the exoscope improved surgeon comfort and interaction with the operating team, despite an initial learning curve. CONCLUSIONS: The exoscope presents notable advantages in terms of visual field and ergonomics. The exoscope's ability to facilitate better posture and team communication without compromising image quality makes it an addition to neurosurgical practice, as in SDR.

Repeat percutaneous rhizotomy for trigeminal neuralgia is not associated with an increased risk of postoperative complications.

BACKGROUND AND OBJECTIVES: Patients undergoing percutaneous rhizotomy for trigeminal neuralgia (TN) may require several procedures to manage their pain. However, it is not fully understood whether repeat procedures influence postoperative complication rates. METHODS: We retrospectively reviewed patients undergoing rhizotomy at our institution from 2011 to 2022. Patients were included only if they had no history of prior interventions including microvascular decompression (MVD) or radiosurgery. We collected baseline patient information, pain characteristics, and postoperative complications for each patient. Patients were dichotomized into those undergoing primary rhizotomy versus those undergoing a repeat rhizotomy. Potential drivers of postoperative complications were included in a multivariate logistic regression model. RESULTS: Of the 1904 cases reviewed, 965 met our inclusion criteria. 392 patients underwent primary rhizotomy, and 573 patients underwent repeat rhizotomies. The repeat rhizotomy group was significantly older, p<0.001. Patients in the repeat rhizotomy group expressed higher frequencies of bilateral pain, p=0.01. Patients in the repeat rhizotomy group demonstrated a significantly higher rate of preoperative numbness and postoperative numbness, p<0.001. There were no significant differences in any of the considered complications between the single rhizotomy and repeat rhizotomy groups. On multivariate logistic regression, repeat rhizotomy did not predict an increased risk of any postoperative complications, p=0.14. CONCLUSIONS: Patients undergoing repeat rhizotomy may be at risk of postoperative numbness but are not at increased risk for postoperative complications. These results are of use to patients who are poor surgical candidates, and thus may require multiple rhizotomies to effectively manage their pain over time.

'I Didn't Know What Was Going to Happen': Children's and Young People's Experiences and Their Involvement Before and After Selective Dorsal Rhizotomy.

AIMS: To explore experiences, expectations, and involvement of children and young people (CYP) in decision-making for selective dorsal rhizotomy (SDR) surgery, post-operative physiotherapy treatment and outcomes. METHODS: A qualitative study design using one to one interviews. Five CYP (2 girls and 3 boys) participated, and interviews lasted between 45 min and 2 h. Data were analyzed using thematic analysis. RESULTS: Children and young people are reliant on their parents to make decisions and inform them of the SDR process. Experiences of living with cerebral palsy and its management are centered on their routine social, psychological, and physiological challenges. Individual characteristics and attributes of CYP have an impact on how they cope with the rehabilitation burden and adjust to their changing levels of function and participation. CONCLUSIONS: Although CYP reported that SDR offers them a greater 'freedom to choose' in how they participate in daily life, further consideration is required to meet their psychosocial needs, particularly in preparing for SDR and adjusting afterwards.

An anatomical study of the subarachnoid space surrounding the trigeminal ganglion in horses-in preparation for a controlled glycerol rhizotomy in equids.

Introduction: Equine trigeminal-mediated headshaking is a painful neuropathic disorder comparable to trigeminal neuralgia in humans. The selective destruction of pain fibers within the trigeminal ganglion, called rhizotomy, is the surgical treatment of choice for idiopathic trigeminal neuralgia refractory to medical treatment in humans. The human trigeminal ganglion is enclosed by a dural recess called the Meckel's or trigeminal cave, in which the ganglion is surrounded by a cerebrospinal fluid (CSF)-filled subarachnoid space. During glycerol rhizotomy, glycerol is percutaneously injected in this CSF-filled space. Until now, information about the anatomy of the dural recess and the subarachnoid space surrounding the trigeminal ganglion is lacking in horses. The aim of this study was to explore if a CSF-filled subarachnoid space around the trigeminal ganglion exists in horses. Materials and methods: Six equine cadaver heads were investigated for CSF accumulation around the ganglion with a 3 Tesla MRI. After anatomical dissection to expose the trigeminal root, a polymer-based radiopaque contrast agent was injected through the porus trigeminus into the subarachnoid space (cisternography). The exact delineation and the volume of the contrast agent accumulation were determined on subsequent micro-computed tomographic scans and segmentation. Finally, the distribution of the contrast agent within the subarachnoid space was examined histologically in three specimens. Results: In all 12 specimens included in this study, the trigeminal ganglion was surrounded by a subarachnoid space forming a trigeminal cistern. The mean volume of the trigeminal cave in this study was 0.31 mL (±SD: 0.11 mL). Distribution of the contrast agent along the peripheral nerves (i.e., ophthalmic, maxillary and/or mandibular nerve) was observed in 7 out of 12 specimens. Discussion/conclusion: A subarachnoid space surrounding the trigeminal ganglion exists in the horse and could be targeted for glycerol rhizotomy in horses suffering from trigeminal-mediated headshaking. However, the clinical relevance of contrast agent distribution along the peripheral nerves remains to be assessed.

Cervicothoracic ventral-dorsal rhizotomy for treatment of brachial hypertonia in cerebral palsy.

PURPOSE: Cervicothoracic ventral-dorsal rhizotomy (VDR) is a potential treatment of medically refractory hypertonia in patients who are not candidates for intrathecal baclofen, particularly in cases of severe upper limb hypertonia with limited to no function. A longitudinal cohort was identified to highlight our institutional safety and efficacy using cervicothoracic VDR for the treatment of hypertonia. METHODS: Retrospective data analysis was performed for patients that underwent non-selective cervicothoracic VDR between 2022 and 2023. Non-modifiable risk factors, clinical variables, and operative characteristics were collected. RESULTS: Six patients (three female) were included. Four patients underwent a bilateral C6-T1 VDR, one patient underwent a left C7-T1 VDR, and another underwent a left C6-T1 VDR. Three patients had quadriplegic mixed hypertonia, one patient had quadriplegic spasticity, one patient had triplegic mixed hypertonia, and one patient had mixed hemiplegic hypertonia. The mean difference of proximal upper extremity modified Ashworth scale (mAS) was - 1.4 ± 0.55 (p = 0.002), and - 2.2 ± 0.45 (p < 0.001) for the distal upper extremity. Both patients with independence noted quality of life improvements as well as increased ease with dressing and orthotics fits. Caregivers for the remaining four patients noted improvements in caregiving provision, mainly in dressing, orthotics fit, and ease when transferring. CONCLUSION: Cervicothoracic VDR is safe and provides tone control and quality of life improvements in short-term follow-up. It can be considered for the treatment of refractory hypertonia. Larger multicenter studies with longer follow-up are necessary to further determine safety along with long-term functional benefits in these patients.

Postoperative pain management strategies following selective dorsal rhizotomy in pediatric cerebral palsy patients: a systematic review of published regimens.

BACKGROUND: Surgical selective dorsal rhizotomy (SDR) in appropriate pediatric cerebral palsy patients is an effective treatment for spasticity. However, there remains heterogeneity reported in postoperative pain management with and without opioid medication in this delicate cohort. The objective of this study was to aggregate pertinent metadata by means of systematic review to summarize all relevant postoperative pain regimens in the literature. METHODS: Searches of multiple electronic databases from inception to June 2024 were conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. Outcomes and regimens were then summarized. RESULTS: A total of 16 cohort studies were included in this study published between 1989 and 2024. Amongst all studies, outcomes were reported for a total of 636 with median cohort age 6.3 years, and median cohort male proportion 62% was reported. Four studies reported regimens involving systemic analgesia, 8 studies reported regimens involving epidural analgesia, and the remaining 4 studies reported regimens involving intrathecal analgesia. All studies primary pain management involved opioid medication, with 8 studies having opioid medication available as indicated, 3 studies having opioid medication as a single dose, and the remaining studies having opioid medication as a continuous agent in the immediate postoperative period. Across all studies, rates of desaturations, nausea and/or vomiting, and pruritis ranged from 0 to 55%, 25 to 82%, and 15 to 70% respectively. Eleven of the 16 studies included a comparative component, demonstrating that their regimen was at least comparable to their control regimen, if not superior. CONCLUSIONS: Multiple variations of postoperative pain management in pediatric cerebral palsy patients following SDR have been reported in the literature, involving systemic, epidural, and intrathecal analgesia. Concerns for adverse effects with the utilization of opioid medication has led to the trend towards multimodal pain management relying more on non-opioid medication regimens in the more recent literature.

Postoperative outcomes and stimulation responses for sectioned nerve roots during selective dorsal rhizotomy in cerebral palsy.

BACKGROUND: Cerebral palsy (CP) is the most cause of motor dysfunction in children. Selective dorsal rhizotomy (SDR) plays a major role in long term spasticity control. However, limited data exists on the effect of SDR on postoperative spasticity treatment requirements and supraspinal effects, and the stimulation responses of dorsal nerve roots in those with CP. METHODS: The current study included the outcome for 35 individuals undergoing SDR for motor functional outcome, spasticity, baclofen dose changes, botulinum toxin injection frequency, and spasticity related orthopedic procedures. We also report on the stimulation responses in 112 individuals who underwent SDR at our institution. RESULTS: There was a significant difference in gross motor function measures (GMFM)-66 scores at last follow up that remained present when considering only ambulatory children but not with non-ambulatory children. Ashworth scores were significantly decreased for both upper and lower extremities after SDR at all follow up points. There was a significant decrease in Baclofen dose and botulinum toxin injections requirements after SDR, but no significant difference in the need for orthopedic intervention. A total of 5502 dorsal nerve roots were tested showing a decrease in stimulation intensity and increase in grade on the right side and for descending lumbosacral levels. CONCLUSIONS: SDR improves gross motor scores during short term follow up but has additional benefits in decreasing baclofen dosing and botulinum toxin injections requirements after surgery. They stimulation responses of sectioned dorsal nerve roots adds to the limited available data and our understanding of the pathological changes that occur in CP.

Informing knowledge translation for selective dorsal rhizotomy: A survey of Australian clinicians and people with lived experience of cerebral palsy.

AIM: Selective dorsal rhizotomy (SDR) is a neurosurgical intervention used to reduce spasticity in children with cerebral palsy (CP). There is minimal relevant, evidence-based information available for Australian families and clinicians. This study aims to investigate the knowledge of people with lived experience and clinicians regarding SDR, including how they currently access information and what information they seek. METHODS: Adults with CP, carers of children with CP and clinicians treating children with CP were invited to complete an online survey. Data regarding participant demographics, current knowledge and confidence in knowledge about CP and SDR, information source/s used and participants level of trust in these sources are presented as counts and percentages. Comparisons in knowledge between groups were analysed. RESULTS: A total of 114 surveys were completed: 63 clinicians, 48 carers, and 3 adults with CP. Eighty percent of clinicians were allied health professionals. People with lived experience were less confident in their knowledge about SDR compared to knowledge of CP (P < 0.001). Clinicians rated scientific research literature and the hospital team as the most useful and trustworthy information source. People with lived experience used a wider range of information sources including the internet, rating their community therapy team and other people with lived experience as the most useful. CONCLUSION: This study identified a lack of confidence in knowledge of SDR for people with lived experience, likely due to a gap in accessible and readable evidence-based information. While both groups differed in how they access information, there was agreement that greater information about SDR is needed.

Partial sensory rhizotomy in recurrent trigeminal neuralgia. Our experience and literature review.

BACKGROUND AND OBJECTIVE: Trigeminal Neuralgia (NT) is a common pathology in Neurosurgery. It can be classified as idiopathic or secondary to other pathologies, such as Multiple Sclerosis (MS). Several surgical treatments have been described, some of them being replaced by more modern techniques. Partial sensory rhizotomy (PSR), described by Dandy is a technique replaced by other techniques due to its permanent side effects. We present our experience with this technique in patients with recurrent NT. METHODS AND MATERIALS: A retrospective review is carried out on five patients who underwent surgery at our center from 2018 to 2023 using the PSR technique. RESULTS: All the patients intervened showed significant clinical improvement, except one patient who required reintervention due to uncontrolled pain. According to the Barrow Neurological Institute (BNI) scale, 80% (4/5) of patients showed improvement from grade V to grades I/II except for one of them. This patient suffered from MS. Additionally, one patient presented a corneal ulcer after surgery due to impairment of the corneal reflex. CONCLUSION: In our experience, PSR is a valid treatment option in selected patients with recurrent TN. It has a low incidence of complications with an adequate surgical technique and anatomical knowledge of the region. To the best of our knowledge, we are one of the few centers in Spain to publish our results with PSR in the last ten years. We report good results in pain control withdrawing medication in 80% (4/5) of the operated patients.

Focal selective dorsal rhizotomy and concurrent deformity correction: a combined approach.

OBJECTIVE: Selective dorsal rhizotomy (SDR) is a neurosurgical procedure to reduce spasticity in children with cerebral palsy and spastic diplegia. The authors developed a procedure called focal SDR for children with spasticity predominantly in the L5 or S1 motor distribution, which can be combined with orthopedic correction of fixed soft-tissue or bony deformity. The authors describe in detail the technique of minimally invasive focal SDR and propose selection criteria. METHODS: The authors conducted a retrospective study of patients who underwent focal SDR at their institution and underwent baseline and 1-year postoperative 3D gait analysis. Modified Ashworth scale (MAS) and Gait Deviation Index (GDI) scores were the primary outcome measures. RESULTS: Ten patients met the study criteria, all with an underlying diagnosis of cerebral palsy. All underwent focal SDR at the unilateral or bilateral S1 level, and 4 additionally underwent focal SDR at the L5 level unilaterally or bilaterally. All but 1 patient underwent concurrent orthopedic surgery. The improvement in spasticity of the plantar flexors, as measured by the MAS score, was 2.2 (p < 0.001). In the patients who underwent L5 focal SDR, there was an improvement in the hamstring MAS score of 1.4 (p = 0.004). The mean improvement in the GDI score following focal SDR was 11 (range -6 to 29, p < 0.001). CONCLUSIONS: Focally impairing spasticity in the gastrocsoleus complex and/or hamstrings muscle group in the setting of less functionally impactful proximal tone is extremely common in cerebral palsy. The novel technique of focal SDR, combined with orthopedic intervention, improves spasticity scores and overall gait mechanics. Further investigation is warranted to define the ideal candidacy and outcomes.

White matter characteristics in children with cerebral palsy prior to selective dorsal rhizotomy: a multicenter diffusion tensor imaging study.

OBJECTIVE: The aims of this study were to 1) assess and quantify white matter (WM) microstructural characteristics derived from diffusion tensor imaging (DTI) in children with cerebral palsy (CP) prior to selective dorsal rhizotomy (SDR), and 2) investigate potential associations between WM diffusion properties and gross motor function and spasticity in children with spastic CP who underwent SDR. METHODS: This study is a multisite study based on DT images acquired prior to SDR as well as postoperative outcome data. DTI data collected from two sites were harmonized using the ComBat approach to minimize intersite scanner difference. The DTI abnormalities between children with spastic CP and controls were analyzed and correlated with the severity of impaired mobility based on the Gross Motor Function Classification System (GMFCS). The improvement in gross motor function and spasticity after SDR surgery was assessed utilizing the Gross Motor Function Measure-66 (GMFM-66), the Modified Tardieu Scale (MTS), and the modified Ashworth scale (MAS). Alterations in these outcome measures were quantified in association with DTI abnormalities. RESULTS: Significant DTI alterations, including lower fractional anisotropy (FA) in the genu of the corpus callosum (gCC) and higher mean diffusivity (MD) in the gCC and posterior limb of the internal capsule (PLIC), were found in children in the SDR group when compared with the age-matched control group (all p < 0.05). Greater DTI alterations (FA in gCC and MD in gCC and PLIC) were associated with lower mobility levels as determined based on GMFCS level (p < 0.05). The pre- to post-SDR improvement in motor function based on GMFM-66 was statistically significant (p = 0.006 and 0.002 at 6-month and 12-month follow-ups, respectively). The SDR efficacy was also identified as improving spasticity in lower-extremity muscle groups assessed with the MTS and MAS. Partial correlation analysis presented a significant association between pre- to post-SDR MTS alteration and DTI abnormalities. CONCLUSIONS: The findings in the present study provided initial quantitative evidence to establish the WM microstructural characteristics in children with spastic CP prior to SDR surgery. The study generated data for the association between baseline DTI characteristics and mobility in children with CP prior to SDR surgery. The study also demonstrated SDR efficacy in improving motor function and spasticity based on the GMFM-66, MTS, and MAS, respectively, in association with DTI data.

Case-based explanation of standard work tools for selective dorsal rhizotomy for cerebral palsy.

OBJECTIVE: Spasticity is a challenging feature of cerebral palsy (CP) that may be managed with selective dorsal rhizotomy (SDR). Although standard work tools (SWTs) have recently been utilized to inform a standard of care for neurosurgical procedures, no SWTs for SDR have been previously described. The authors present the multidisciplinary approach SWTs for SDR used at their institutions to promote consistency in the field and minimize complication rates. METHODS: A multidisciplinary approach was used to define all steps in the SDR pathway. Preoperative, intraoperative, and postoperative workflows were synthesized, with specific efforts to improve mobility through inpatient rehabilitation and minimize infection. RESULTS: The SWTs have been implemented at two institutions for 7 years. An illustrative case of a patient aged 3 years 10 months with a history of premature birth at 29 weeks, spastic-diplegic CP, right-sided periventricular leukomalacia, and developmental delay who underwent L2-S1 SDR is presented. CONCLUSIONS: The authors detail SWTs for SDR developed by a multidisciplinary team with specific steps at all points in the patient pathway. The illustrative case emphasizes that SWTs may help ensure the safety of SDR while maximizing its long-term efficacy for individuals with CP.

History and evolution of surgical treatment for spasticity: a journey from neurotomy to selective dorsal rhizotomy.

The evolution of neurosurgical approaches to spasticity spans centuries, marked by key milestones and innovative practitioners. Probable ancient descriptions of spasmodic conditions were first classified as spasticity in the 19th century through the interventions of Dr. William John Little on patients with cerebral palsy. The late 19th century witnessed pioneering efforts by surgeons such as Dr. Charles Loomis Dana, who explored neurotomies, and Dr. Charles Sherrington, who proposed dorsal rhizotomy to address spasticity. Dorsal rhizotomy rose to prominence under the expertise of Dr. Otfrid Foerster but saw a decline in the 1920s due to emerging alternative procedures and associated complications. The mid-20th century saw a shift toward myelotomy but the revival of dorsal rhizotomy under Dr. Claude Gros' selective approach and Dr. Marc Sindou's dorsal root entry zone (DREZ) lesioning. In the late 1970s, Dr. Victor Fasano introduced functional dorsal rhizotomy, incorporating electrophysiological evaluations. Dr. Warwick Peacock and Dr. Leila Arens further modified selective dorsal rhizotomy, focusing on approaches at the cauda equina level. Later, baclofen delivered intrathecally via an implanted programmable pump emerged as a promising alternative around the late 1980s, pioneered by Richard Penn and Jeffrey Kroin and then led by A. Leland Albright. Moreover, intraventricular baclofen has also been tried in this matter. The evolution of these neurosurgical interventions highlights the dynamic nature of medical progress, with each era building upon and refining the work of significant individuals, ultimately contributing to successful outcomes in the management of spasticity.

Palliative single-level selective dorsal rhizotomy for children with spastic cerebral palsy Gross Motor Function Classification System level IV and V: a case series and systematic review of the literature.

OBJECTIVE: Single-level selective dorsal rhizotomy (SDR), typically indicated for ambulatory patients, is a controversial topic for severe spastic cerebral palsy (CP) with Gross Motor Function Classification System (GMFCS) level IV or V. The objective of this case series and systematic literature review was to outline the indication and outcome of palliative SDR for nonambulatory patients with CP and GMFCS level IV and V, focusing on improvement of spasticity and of patient and caregiver reported quality of life assessment. METHODS: A retrospective case series of patients with CP and GMFCS level IV or V who underwent single-level SDR at the authors' institution is presented. Furthermore, two databases (PubMed and Embase) were searched and a systematic review with a search string based on the terms "selective dorsal rhizotomy," "cerebral palsy," and "outcome" was conducted. The primary outcome was the reduction of spasticity based on the modified Ashworth scale (MAS). Secondary outcomes were change on the Gross Motor Function Measure-66 (GMFM-66), evaluation of patient-reported outcome measures (PROMs), surgical morbidity, and mortality. RESULTS: Eleven consecutive children under the age of 25 years undergoing palliative single-level SDR were included. All patients showed a reduction in MAS score (mean 1.09 ± 0.66 points) and no surgical morbidity and mortality occurred. For the systematic review results from our case series, in addition to 4 reports, 274 total patients were included. Reduction of spasticity based on MAS score was noted in all studies (mean range 1.09-3.2 points). Furthermore, in 2 studies spasticity of the upper extremities showed a MAS score reduction as well (range 1.7-2.8 points). The GMFM-66 score improved in 72% of the patients, while bladder function improved in 78% of the patients. Based on the PROMs, 92% of the patients/caregivers were satisfied with the outcome and their quality of life after the procedure. Two wound infections (2.7%) and one CSF leak (1.3%) occurred, while no surgery-related deaths were described. CONCLUSIONS: This analysis showed an improvement in spasticity, daily care, and comfort for patients with CP and GMFCS levels IV and V. Larger cohorts analyzing the outcome of palliative single-level SDR, based on the MAS, GMFM-66, and PROMs, are still needed and should be the focus of future studies. Systematic review registration no.: CRD42024495762 (https://www.crd.york.ac.uk/prospero/).

A history of stereotactic radiosurgery may predict failure of procedure following percutaneous glycerol rhizotomy for trigeminal neuralgia.

BACKGROUND: Both stereotactic radiosurgery (SRS) and percutaneous glycerol rhizotomy are excellent options to treat TN in patients unable to proceed with microvascular decompression. However, the influence of prior SRS on pain outcomes following rhizotomy is not well understood. METHODS: We retrospectively reviewed all patients undergoing percutaneous rhizotomy at our institution from 2011 to 2022. Only patients undergoing percutaneous glycerol rhizotomy following SRS (SRS-rhizotomy) or those undergoing primary glycerol rhizotomy were considered. We collected basic demographic, clinical, and pain characteristics for each patient. Additionally, we characterized pain presentation and perioperative complications. Immediate failure of procedure was defined as presence of TN pain symptoms within 1-week of surgery, and short-term failure was defined as presence of TN pain symptoms within 3-months of surgery. A multivariate logistic regression model was used to evaluate the relationship of a history SRS and failure of procedure following percutaneous glycerol rhizotomy. RESULTS: Of all patients reviewed, 30 had a history of SRS prior to glycerol rhizotomy whereas 371 underwent primary percutaneous glycerol rhizotomy. Patients with a history of SRS were more likely to endorse V3 pain symptoms, p = 0.01. Additionally, patients with a history of SRS demonstrated higher preoperative BNI pain scores, p = 0.01. Patients with a history of SRS were more likely to endorse preoperative numbness, p < 0.0001. A history of SRS was independently associated with immediate failure [OR = 5.44 (2.06-13.8), p < 0.001] and short-term failure of glycerol rhizotomy [OR = 2.41 (1.07-5.53), p = 0.03]. Additionally, increasing age was found to be associated with lower odds of short-term failure of glycerol rhizotomy [OR = 0.98 (0.97-1.00), p = 0.01] CONCLUSIONS: A history of SRS may increase the risk of immediate and short-term failure following percutaneous glycerol rhizotomy. These results may be of use to patients who are poor surgical candidates and require multiple noninvasive/minimally invasive options to effectively manage their pain.

Nonselective lumbosacral ventral-dorsal rhizotomy for the management of lower-limb hypertonia in nonambulatory children with cerebral palsy.

OBJECTIVE: Children with cerebral palsy (CP) often experience medically refractory hypertonia, for which there are surgical therapies including neuromodulation and rhizotomy. Traditional surgical treatment for medically refractory mixed hypertonia or dystonia includes intrathecal baclofen pumps and selective dorsal rhizotomy. A nonselective lumbosacral ventral-dorsal rhizotomy (VDR; ventral and dorsal roots lesioned by 80%-90%) has the potential to address the limitations of traditional surgical options. The authors highlighted the institutional safety and efficacy of nonselective lumbosacral VDR for palliative tone management in nonambulatory patients with more severe CP. METHODS: The authors performed a retrospective analysis of patients who had undergone lumbosacral VDR between 2022 and 2023. Demographic factors, clinical variables, and operative characteristics were collected. The primary outcomes of interest included tone control and quality of life improvement. Secondary outcome measures included, as a measure of safety, perioperative events such as paresthesias. Postoperative complications were also noted. RESULTS: Fourteen patients (7 female) were included in the study. All patients had undergone a T12-L2 osteoplastic laminoplasty and bilateral L1-S1 VDR. Nine patients had quadriplegic mixed hypertonia, 4 had quadriplegic spasticity, and 1 had generalized secondary dystonia. Following VDR, there was a significant decrease in both lower-extremity modified Ashworth Scale (mAS) scores (mean difference [MD] -2.77 ± 1.0, p < 0.001) and upper-extremity mAS scores (MD -0.71 ± 0.76, p = 0.02), with an average follow-up of 3 months. In the patient with generalized dystonia, the lower-extremity Barry-Albright Dystonia Scale score decreased from 8 to 0, and the overall score decreased from 32 to 13. All parents noted increased ease in caregiving, particularly in terms of positioning, transfers, and changing. The mean daily enteral baclofen dose decreased from 47 mg preoperatively to 24.5 mg postoperatively (p < 0.001). Three patients developed wound dehiscence, 2 of whom had concurrent infections. CONCLUSIONS: Lumbosacral VDR is safe, is effective for tone control, and can provide quality of life improvements in patients with medically refractory lower-limb mixed hypertonia. Lumbosacral VDR can be considered for palliative tone control in nonambulatory patients with more severe CP. Larger studies with longer follow-ups are necessary to further determine safety and long-term benefits in these patients.

Percutaneous thermal radiofrequency rhizotomy of L2-S1 spinal nerve roots in children with cerebral palsy.

OBJECTIVE: This study presents the results of an evaluation of the effectiveness of percutaneous thermal radiofrequency (RF) ablation of spinal nerve roots to reduce spasticity and improve motor function in children with cerebral palsy (CP). METHODS: A retrospective analysis was conducted on the surgical treatment outcomes of 26 pediatric patients with severe CP (Gross Motor Function Classification System levels IV-V). The assessment protocol included muscle tone assessment using the modified Ashworth scale (MAS), evaluation of passive and active range of motion, gait video recording, and locomotor status evaluation using the Gross Motor Function Measure (GMFM)-88 scale. Thermal RF rhizotomy (ablation of spinal nerve roots) was performed on all patients at the L2-S1 levels at 70°C for 90 seconds. The statistical data analysis was conducted using the t-test and Mann-Whitney U-test. A p value < 0.05 was considered statistically significant. RESULTS: Before the operation, the average level of spasticity in the lower-limb muscles of all patients was 3.0 ± 0.2 according to the MAS. In the early postoperative period, the spasticity level in all examined muscle groups significantly decreased to a mean of 1.14 ± 0.15 (p < 0.001). In the long-term postoperative period, the spasticity level in the examined muscle groups averaged 1.49 ± 0.17 points on the MAS (p < 0.001 compared to baseline, p = 0.0416 compared to the early postoperative period). Despite the marked reduction of spasticity in the lower limbs, no significant change in locomotor status according to the GMFM-88 scale was observed in the selected category of patients. In the long-term period, during the control examination of patients, the GMFM-88 level increased on average by 3.6% ± 1.4% (from 22.2% ± 3.1% to 25.8% ± 3.6%). CONCLUSIONS: The findings of this study offer preliminary yet compelling evidence that RF ablation of spinal nerve roots can lead to a significant and enduring decrease in muscle tone among children with severe spastic CP. Further studies and longer-term data of the impact on functionality and quality of life of patients with CP after spinal root RF ablation are needed.

Single-level laminoplasty approach to selective dorsal rhizotomy with conus localization by rapid spine MRI.

INTRODUCTION: While selective dorsal rhizotomy (SDR) was originally described as a multilevel approach, single-level approaches are now popularized. Conus localization is beneficial for operative planning in single-level selective dorsal rhizotomy. Our approach to SDR involves minimal exposure for a single-level laminoplasty, preserving one attached interspinous ligament. Pre-operative conus localization is required for this tailored approach to determine the laminoplasty level and dictate rostral or caudal division of the superior spinus ligament. While rapid MRI sequences have been popularized for pediatric cranial imaging, its utility for spinal imagining is less well-described, and specific application for conus localization has not been reported. OBJECTIVE: Illustrate that rapid MRI without sedation is sufficient to identify conus level for tailored single-level laminoplasty SDR. MATERIAL AND METHODS: Patients undergoing SDR from 2014 to 2022 at one institution were reviewed for type of pre-operative MRI (rapid vs full), conus level, procedural time for MRI, and radiology report. The typical rapid MRI has four sequences utilizing single-shot technique (scout, sagittal T2, axial T2, and axial T1) that typically take less than 1 min each of acquisition time, with non-single-shot sequences added periodically in cooperative patients. To include time for patient positioning, pre-scan shimming, procedural incidentals, and other patient-specific variations, MRI procedure length was recorded as documented in the electronic medical record. RESULTS: N = 100 patients had documentation of an MRI for pre-operative imaging. Seventy-nine of these had a rapid MRI, and 21 required a full MRI with anesthesia for their treatment plan. Mean total procedure time for rapid MRI was 21.5 min (median 17). Mean procedure time for MRI under general anesthesia was 91.2 min (median 94). Of patients with rapid MRI imaging, 2/79 had an ambiguous conus level (1 from motion artifact, 1 from spinal hardware) vs 1/21 with a full MRI under anesthesia (due to spinal hardware). CONCLUSION: Rapid spinal MRI without sedation can be used for conus localization in a pediatric population. This may be routinely used as pre-operative imaging for a single-level approach to selective dorsal rhizotomy, without sedation or intubation procedures.

The Application of Radiofrequency Ablation in Acute and Chronic Pain Management.

Radiofrequency ablation (RFA), also known as rhizotomy, is one of the frequently used modalities in interventional pain management. This nonsurgical procedure delivers radiofrequency waves to the targeted nerves to interrupt transmission of nociceptive signals from the peripheral tissues to the central nervous system, thereby reducing pain perception. Recent studies have demonstrated the efficacy of RFA treatment as an effective interventional pain management technique to treat a variety of acute and chronic pain conditions including facial pain, headaches, postmastectomy, musculoskeletal, and major joint pain (knee, hip, shoulder, sacroiliac), and cancer pain. As more certified registered nurse anesthetists are involved in pain management, it is important to be familiar with current nonsurgical pain interventions. This journal course describes the unique mechanism of action of radiofrequency for pain modulation and provides emerging evidence to support its applications in both acute and chronic pain management.