Dorsal root entry zone lesioning for brachial plexus avulsion - technical evolution and long-term follow-up.

BACKGROUND: Brachial plexus avulsion (BPA) injuries can cause severe deafferentation pain. This has been successfully treated with dorsal root entry zone (DREZ) lesioning. Distortions in anatomy following a BPA injury can make identifying neural structures challenging. We describe a modification to the operative technique that improves the surgical view and the advanced intraoperative neuromonitoring (IONM) employed to identify DREZ. We have analysed the long-term outcomes for pain, quality of life, and complications in patients undergoing DREZ lesioning. METHODS: This is a single-centre retrospective case series including patients who underwent DREZ lesioning with IONM for brachial plexus avulsion between 2012 and 2022. Analysed data included pre- and postoperative pain (VAS), quality of life score for chronic pain, and complications. The evolution of the surgical approach is discussed. RESULTS: 44 consecutive patients underwent a DREZ lesioning procedure with intraoperative monitoring and mapping. In these patients the mean VAS score improved from 8.9 (7-10) to 1.87 (0-6) (p < 0.0001) at the time of discharge. 31 patients were followed-up for more than 12 months with a mean duration of follow-up of 41 months and their results were as follows: the mean VAS improved from 9.0 (7-10) to 4.1 (0-9) (p < 0.0001) at the last follow-up and the mean QOL values improved from 3.7 (2-6) to 7.4 (4-10) (p < 0.0001). The long-term outcomes were 'good' in 39%, 'fair' in 29% and 'poor' in 32% of patients. 55% of the patients were able to stop or reduce pain medications. CONCLUSIONS: Modifications of surgical technique provide better exposure of DREZ, and IONM aids in identifying DREZ in the presence of severe intra-dural changes. Long-term outcomes of DREZ lesioning indicate not only a reduction in pain but also a significant improvement in quality of life.

Dual target deep brain stimulation for complex essential and dystonic tremor - A 5-year follow up.

BACKGROUND: Essential tremor (ET) is characterized by action tremor of the upper limbs, head tremor and voice tremor. Dystonic tremor (DT) is produced by muscle contractions in a body affected by dystonia. Deep brain stimulation (DBS) of ventral intermediate nucleus of the thalamus (VIM) is the most well-known advanced treatment for medication-refractory tremor. However, decline in efficacy overtime has led to explore other targets. This study aimed to measure the efficacy of bilateral dual targeting ViM/caudal Zona Incerta (cZI) stimulation on tremor control. A secondary aim was to evaluate if there was a difference in the efficacy between ET and DT. METHODS: 36 patients were retrospectively recruited at the Walton NHS Foundation Trust, Liverpool, UK. Patients were assessed pre-operatively, and then at 1-year, 3-years, and 5-years post-operatively with the following scales: Fahn-Tolosa-Marin tremor rating (FTMTR) scale, EuroQol-5D, and Hospital Anxiety and Depression Scale. RESULTS: Bilateral ViM-cZI DBS significantly improved overall tremor score by 45.1% from baseline to 3-years post-operatively (p < 0.001). It continued to show improvement in overall FTMTR score by 30.7% at 5-years but this failed to meet significance. However, there was no significant improvement of mood or quality of life (QoL) scores. ET group on average showed a significant better clinical outcome compared to the DT group (p > 0.001). CONCLUSIONS: Our study found that bilateral ViM-cZI DBS treatment had a favourable effect on motor symptoms sustained over the 5-years in tremor patients, especially in ET group. There was limited effect on mood and QoL with similar trends in outcomes for both tremor types.

Bilateral globus pallidus internus (GPi) deep brain stimulation for cervical dystonia: Effects on motor and non-motor symptoms within 5 years follow.

BACKGROUND: Cervical Dystonia ("CD") is a movement disorder characterised by sustained muscle contractions in the neck, causing involuntary posturing. Deep brain stimulation ("DBS") of the globus pallidal internus (GPi) is advanced treatment for pharmaco-refractory patients. As CD is a rare disease, cohort studies are often limited to patients of heterogenous disease profile, small sample size or short follow-up. This study firstly aimed to measure the efficacy of GPi-DBS on motor and non-motor symptoms of CD. A secondary aim was to evaluate if clinical factors - such as age, disease duration and baseline disease severity - influence variability of motor outcomes. METHODS: 37 idiopathic CD patients were recruited from movement disorders clinics at The Walton NHS Foundation Trust, Liverpool, UK. Patients were assessed pre-operatively, and 1 year, 3 years and 5 years post-operatively with the following clinical scales: Toronto Western Spasmodic Torticollis Rating Scale ("TWSTRS"), Hospital Anxiety and Depression Scale and EuroQuol-5D. RESULTS: GPI-DBS significantly improved overall TWSTRS scores by 57% from baseline to 5Y FU (p < 0.001). It also significantly improved TWSTRS severity, disability, and pain sub-scores by 72%, 59% and 46% respectively. We did not find a significant improvement in mood or quality of life scores at 5 years. Similarly, clinical factors at baseline did not correlate with variability in motor outcome. CONCLUSION: We concluded that GPi-DBS is an effective treatment for motor symptoms and pain in CD. There was limited effect on mood and QoL, and no clinical predictive factors of outcome were identified.

Open Thoracic Cordotomy for Cancer Pain with Intraoperative Neuromonitoring: A Case Series and Critical Review of the Literature.

OBJECTIVE: Cordotomy is a viable option for patients with intractable cancer pain and limited survival. Open thoracic cordotomy is offered when patients are not candidates for percutaneous cordotomy. After the open procedure, traditionally performed purely based on anatomic landmarks, up to 22% of patients experience postoperative limb weakness. The objective of this study is to report our experience with neurophysiology-guided open cordotomy along with a critical review of the literature. METHODS: Between 2019 and 2022, 5 open thoracic cordotomies were performed in our center. Intraoperative neurophysiologic monitoring was used in all cases to guide the lesion and standard single-level laminectomy or hemilaminectomy was performed for exposure. Outcome measures were retrospectively reviewed focusing on pain control and neurologic status. Existing literature on cordotomy was critically reviewed. RESULTS: There was satisfactory pain relief with preservation of motor function in all 5 cases. Temperature sensation was preserved in all but 1 patient, who lost it after the previous ipsilateral percutaneous cordotomy (PCC). No procedural complications were experienced. We found that the neurophysiology monitoring lesion was guided anterior compared with what would have been lesioned on an anatomic basis. CONCLUSIONS: Open thoracic cordotomy is a safe and effective procedure for intractable cancer-related pain. Technical advancements significantly reduced mortality and major morbidity of PCC. Our series suggests that neurophysiology monitoring alters the location of the lesion and may help better targeting of pain fibers within the spinothalamic tract and preserve other long tracts. The safety profile of open cordotomy with neurophysiology compares favorably with the PCC.

A structural magnetic resonance imaging review of clinical motor outcomes from deep brain stimulation in movement disorders.

Patients with movement disorders treated by deep brain stimulation do not always achieve successful therapeutic alleviation of motor symptoms, even in cases where surgery is without complications. Magnetic resonance imaging (MRI) offers methods to investigate structural brain-related factors that may be predictive of clinical motor outcomes. This review aimed to identify features which have been associated with variability in clinical post-operative motor outcomes in patients with Parkinson's disease, dystonia, and essential tremor from structural MRI modalities. We performed a literature search for articles published between 1 January 2000 and 1 April 2022 and identified 5197 articles. Following screening through our inclusion criteria, we identified 60 total studies (39 = Parkinson's disease, 11 = dystonia syndromes and 10 = essential tremor). The review captured a range of structural MRI methods and analysis techniques used to identify factors related to clinical post-operative motor outcomes from deep brain stimulation. Morphometric markers, including volume and cortical thickness were commonly identified in studies focused on patients with Parkinson's disease and dystonia syndromes. Reduced metrics in basal ganglia, sensorimotor and frontal regions showed frequent associations with reduced motor outcomes. Increased structural connectivity to subcortical nuclei, sensorimotor and frontal regions was also associated with greater motor outcomes. In patients with tremor, increased structural connectivity to the cerebellum and cortical motor regions showed high prevalence across studies for greater clinical motor outcomes. In addition, we highlight conceptual issues for studies assessing clinical response with structural MRI and discuss future approaches towards optimizing individualized therapeutic benefits. Although quantitative MRI markers are in their infancy for clinical purposes in movement disorder treatments, structural features obtained from MRI offer the powerful potential to identify candidates who are more likely to benefit from deep brain stimulation and provide insight into the complexity of disorder pathophysiology.

Could ZI have a role in DBS for Parkinson's Disease? An observational study to optimize DBS target localization.

Deep Brain Stimulation (DBS) of the subthalamic nucleus (STN) is a well-recognized intervention for Parkinson's Disease (PD). We used LEAD-DBS, a toolbox facilitating DBS electrode reconstructions and computer simulations based on postoperative MRI and CT imaging, to investigate the interaction and followed benefits of electrical field generated by STN-DBS and surrounding areas, such as caudal Zona Incerta (cZI). Thirty-two PD patients, treated with directional STN-DBS in the period 2016-2018 at the Walton Center NHS Foundation Trust, were retrospectively recruited. Their MRI and CT imaging were analyzed with LEAD-DBS to measure the volume of tissue activated (VTA). Considering the clinical outcome based on the UPDRS III score improvement of 62.65% at 6 months follow up, we found a VTA intersection of 21.5% with motor STN and 61.7% with cZI. These observations may support the contribution of cZI deep stimulation to improve clinical outcome of PD patients treated with DBS, promoting the intriguing path of dual targeting.

Re-Exploration of Microvascular Decompression in Recurrent Trigeminal Neuralgia and Intraoperative Management Options.

BACKGROUND: Trigeminal neuralgia (TGN) is a debilitating disorder, and in patients for whom medical management is not sufficient, there are several therapeutic options. Microvascular decompression (MVD) for TGN has been shown to be highly effective; however, pain does recur after MVD in some patients. Therapeutic options for recurrent TGN are the same as those for primary TGN, including re-exploration of MVD (re-MVD). In this study we review our practice of re-MVD, comparing it with alternative options and assessing its safety and efficacy. METHODS: Retrospective analysis of prospectively collected data of patients undergoing re-MVD between 2007 and 2016. RESULTS: Thirty-two patients underwent re-MVD, all with a Barrow Neurosurgical Institute Pain Index (BNPI) of IV or V. Postoperatively, 87% of patients reported an improvement in their BNPI to III or better, with 50% being BNPI 1 or 2. Eleven patients without distortion or vascular conflict at the time of re-exploration underwent intraoperative neurolysis, and 90% reported improvement in their BNPI. Kaplan-Meier analysis showed a median pain-free period of 36 months after re-MVD. There were no significant complications. CONCLUSIONS: Re-MVD is a safe and effective method of treating recurrent TGN. Intraoperative neurolysis is an important tool in re-exploration and should be considered when there is no ongoing compression or distortion of the trigeminal nerve.

The long-term outcomes of epilepsy surgery.

OBJECTIVE: Despite modern anti-epileptic drug treatment, approximately 30% of epilepsies remain medically refractory and for these patients, epilepsy surgery may be a treatment option. There have been numerous studies demonstrating good outcome of epilepsy surgery in the short to median term however, there are a limited number of studies looking at the long-term outcomes. The aim of this study was to ascertain the long-term outcome of resective epilepsy surgery in a large neurosurgery hospital in the U.K. METHODS: This a retrospective analysis of prospectively collected data. We used the 2001 International League Against Epilepsy (ILAE) classification system to classify seizure freedom and Kaplan-Meier survival analysis to estimate the probability of seizure freedom. RESULTS: We included 284 patients who underwent epilepsy surgery (178 anterior temporal lobe resections, 37 selective amygdalohippocampectomies, 33 temporal lesionectomies, 36 extratemporal lesionectomies), and had a prospective median follow-up of 5 years (range 1-27). Kaplan-Meier estimates showed that 47% (95% CI 40-58) remained seizure free (apart from simple partial seizures) at 5 years and 38% (95% CI 31-45) at 10 years after surgery. 74% (95% CI 69-80) had a greater than 50% seizure reduction at 5 years and 70% (95% CI 64-77) at 10 years. Patients who had an amygdalohippocampectomy were more likely to have seizure recurrence than patients who had an anterior temporal lobe resection (p = 0.006) and temporal lesionectomy (p = 0.029). There was no significant difference between extra temporal and temporal lesionectomies. Hippocampal sclerosis was associated with a good outcome but declined in relative frequency over the years. CONCLUSION: The vast majority of patients who were not seizure free experienced at least a substantial and long-lasting reduction in seizure frequency. A positive long-term outcome after epilepsy surgery is possible for many patients and especially those with hippocampal sclerosis or those who had anterior temporal lobe resections.

Tremor reduction and quality of life after deep brain stimulation for multiple sclerosis-associated tremor.

BACKGROUND: Tremor is an important cause of disability and poor quality of life amongst multiple sclerosis (MS) patients. We assessed the outcomes of ventral intermediate (VIM) nucleus deep brain stimulation for the treatment of multiple sclerosis (MS)-associated tremor at a single centre in a prospective fashion. METHODS: Sixteen patients (9 female, 7 male) with a mean age of 41.7 years (range 24-59) underwent surgery. The median duration of MS prior to surgery was 6.5 years and median duration of tremor prior to surgery was 4 years. Case selection was by multidisciplinary assessment with carers, therapists, neurosurgeons and movement disorder neurologists. Tremor was scored pre-operatively and at 6 to 12 months post operatively using Bain and/or Fahn-Tolosa-Marin systems. The Euro-Qol 5D tool was used to assess quality of life before and after surgery. RESULTS: The mean tremor reduction was 39 % with a range between 0 and 87 %. Five of 16 patients achieved at least 50 % tremor reduction and 11 of 16 achieved at least 30 % tremor reduction at last follow up, mean 11.6 months (range 3-80). Tremor was significantly reduced as rated by Bain scores (Wilcoxon matched pairs, Z = 3.07, p = .002) and tended to significance as rated by Fahn scores (Wilcoxon matched pairs, Z = 1.85, p = 0.06). Sub-analysis of activities of daily living measures from the Fahn system showed post operative improvement in feeding (statistically significant), hygiene, dressing, writing and working. Mean visual analogue scores (0-100) of patient reported well-being increased from 54.6 to 57.4 post operatively with a trend to significance (Student's t-test, t = 1.26, p = 0.2). Euro-Qol 5D utility values increased following surgery with a trend to significance which was greater in the group with at least 50 % tremor reduction than in those with none or at least 30 % tremor reduction. CONCLUSIONS: VIM DBS may reduce severe, disabling tremor in patients with MS. This tremor reduction tends to be associated with improved quality of life and function in those who respond. Patient reported outcome measures may not correlate with physician rated clinical outcome such as tremor scoring systems and more subtle assessment of these patients is required.

Subdural empyema secondary to sinus infection in children.

OBJECTIVE: To evaluate the impact, on morbidity and mortality, of aggressive surgical management of subdural empyema of sinus origin in children. METHOD: The authors conducted a retrospective review of 20 children admitted between 2000-2007 to Alder Hay Children Hospital and The Walton centre for Neurology and Neurosurgery for subdural empyema secondary to sinus infection. Clinical presentation, duration of symptoms, radiological investigations, surgical treatment and post-operative outcome were evaluated. RESULTS: Outcome was favourable in 19 cases. In four cases, there were re-accumulation requiring surgical evacuation, four patients experienced post-operative seizures but were seizure-free at follow-up. There was only one mortality in the series. CONCLUSION: Subdural empyema secondary to sinus infection, although uncommon, it could be associated with a relative high morbidity and mortality rate. Early aggressive surgical and medical management with drainage of intracranial or sinus collections and antibiotics therapy lead to a low mortality or morbidity rate and good clinical outcome.

Initial management of hydrocephalus associated with Chiari malformation Type I-syringomyelia complex via endoscopic third ventriculostomy: an outcome analysis.

OBJECT: The aim of this study was to evaluate the efficacy of endoscopic third ventriculostomy (ETV) in patients with Chiari malformation Type I (CM-I) and hydrocephalus with or without syringomyelia. METHODS: The authors identified, in a prospective endoscopy database, 16 adults and children (age range 2-68 years) with CM-I and hydrocephalus that had been managed with ETV. They reviewed the clinical features and radiographic findings for all patients. Fifteen patients underwent ETV as a primary treatment, whereas 1 patient underwent the procedure at the time of shunt failure. All patients had symptomatic hydrocephalus with either aqueductal or fourth ventricular outflow obstruction. The mean duration of follow-up was 42 months. RESULTS: Fifteen patients (94%) remain shunt free following ETV for CM-I. Five (83%) of the 6 patients with a syrinx had improvement or resolution of the syrinx following ETV. Six patients (37.5%) underwent foramen magnum decompression for persistent CM-I -- or syrinx-related symptoms. There was no cerebrospinal fluid leakage or intracranial pressure-related problem following foramen magnum decompression. CONCLUSIONS: Endoscopic third ventriculostomy provides a durable method of treatment for hydrocephalus associated with CM-I. It is effective as a primary treatment, and the authors advocate its use as a replacement for routine ventriculoperitoneal shunt insertion in these patients. Management of the hydrocephalus alone is often sufficient and may obviate decompression, although a significant proportion of patients will still need both procedures.