Integrative approaches in spinal cord stimulation: Neuropathic pain management and motor recovery in spinal cord injury. A narrative review.

Introduction: Spinal cord stimulation is a widespread treatment of chronic neuropathic pain from different conditions. Several novel and improving technologies have been recently developed to increase the effect of neuromodulation in patients refractory to pharmacological therapy. Research question: To explore spinal cord stimulation's mechanisms of action, indications, and management. Material and methods: The paper initially explores the mechanism of action of this procedure based on the generation of an electric field between electrodes placed on the posterior dural surface of the spinal cord probably interfering with the transmission of pain stimuli to the brain. Subsequently, the most consolidated criteria for selecting patients for surgery, which constitute a major issue of debate, were defined. Thereafter, the fundamental patterns of stimulation were summarized by exploring the advantages and side effects. Lastly, the most common side effects and the related management were discussed. Results: Proper selection of the patient is of paramount importance to achieve the best results from this specific neuromodulation treatment. Regarding the different types of stimulation patterns, no definite evidence-based guidelines exist on the most appropriate approach in relation to the specific type of neuropathic pain. Both burst stimulation and high-frequency stimulation are innovative techniques that reduce the risk of paresthesias compared with conventional stimulation. Discussion and conclusion: Novel protocols of stimulation (burst stimulation and high frequency stimulation) may improve the trade-off between therapeutic benefits and potential side effects. Likewise, decreasing the rates of hardware-related complications will be also useful to increase the application of neuromodulation in clinical settings.

How to avoid intraoperative complications of active paragangliomas?

Background: Paragangliomas (PGs) are very rare neuroendocrine tumors that can be found in unusual locations such as the spinal canal. Some PGs may be endocrinologically active, containing neurotransmitters such as noradrenaline, adrenaline, and serotonin. This can lead to unexpected neurotransmitter release during the removal of PGs, leading to a hypertensive crisis. Case Description: We present two patients who underwent surgical removal of a secretory filum terminale PG. Conclusion: If laboratory tests are suggestive of a secretory tumor, surgery should include anesthesiologic preparation similar to cases of pheochromocytoma.

Degenerative L4-L5 spondylolisthesis and stenosis surgery: does over-level flavectomy technique influence clinical outcomes and rates of cranial adjacent segment disease?

BACKGROUND: One of the most dreaded long-term complications related to L4-L5 lumbar arthrodesis is the onset of adjacent segment disease, which most frequently occurs at the cranial level. Few studies have compared the rates of cranial adjacent segment disease (CASD) in patients undergoing lumbar fusion associated with total laminectomy at the same level with those undergoing partial laminectomy. No study has examined the role of selective over-level flavectomy (OLF; i.e., L3-L4). METHODS: A total of 299 patients undergoing posterolateral arthrodesis (PLA) for L4-L5 degenerative spondylolisthesis were retrospectively analyzed with a 5-year follow-up. 148 patients underwent PLA + L4-L5 flavectomy + L4 partial laminectomy (control group), while 151 underwent PLA + L4-L5 flavectomy + total L4 laminectomy + L3-L4 flavectomy (OLF group). Rates of reoperations due to CASD were examined utilizing Cox proportional hazard models, while clinical improvement at follow-up (measured in ODI) was analyzed using generalized linear models (GLMs). Adjustments for potential confounders were made (grade of lumbar lordosis, age, sex, BMI, intervertebral disc degeneration, and presurgical cranial spinal stenosis). RESULTS: At 5 years from the operation, 16 patients (10.8%) in the control group had undergone revision surgery for CASD compared to 5 patients (3.3%) in the OLF group (p = 0.013). Survival analysis and GLM demonstrated that the OLF group had a significantly lower incidence of CASD and presented more favorable clinical outcome. There were no differences in the rate of discal degeneration or the onset of Meyerding's grade I degenerative spondylolisthesis at the adjacent segment. BMI was the only other significant predictor of ODI improvement and of the incidence of CASD. CONCLUSIONS: In patients with L4-L5 degenerative spondylolisthesis and stenosis, the OLF technique may lower rates of CASD and improve clinical outcomes by preventing cranial spinal stenosis without increasing iatrogenic instability or accelerating intervertebral disc degenerative changes.

MER and increased operative time are not risk factors for the formation of pneumocephalus during DBS.

Although only recently directional leads have proven their potential to compensate for sub-optimally placed electrodes, optimal lead positioning remains the most critical factor in determining Deep Brain Stimulation (DBS) outcome. Pneumocephalus is a recognized source of error, but the factors that contribute to its formation are still a matter of debate. Among these, operative time is one of the most controversial. Because cases of DBS performed with Microelectrode Recordings (MER) are affected by an increase in surgical length, it is useful to analyze whether MER places patients at risk for increased intracranial air entry. Data of 94 patients from two different institutes who underwent DBS for different neurologic and psychiatric conditions were analyzed for the presence of postoperative pneumocephalus. Operative time and use of MER, as well as other potential risk factors for pneumocephalus (age, awake vs. asleep surgery, number of MER passages, burr hole size, target and unilateral vs. bilateral implants) were examined. Mann-Whitney U and Kruskal-Wallis tests were utilized to compare intracranial air distributions across groups of categorical variables. Partial correlations were used to assess the association between time and volume. A generalized linear model was created to predict the effects of time and MER on the volume of intracranial air, controlling for other potential risk factors identified: age, number of MER passages, awake vs. asleep surgery, burr hole size, target, unilateral vs. bilateral surgery. Significantly different distributions of air volume were noted between different targets, unilateral vs. bilateral implants, and number of MER trajectories. Patients undergoing DBS with MER did not present a significant increase in pneumocephalus compared to patients operated without (p = 0.067). No significant correlation was found between pneumocephalus and time. Using multivariate analysis, unilateral implants exhibited lower volumes of pneumocephalus (p = 0.002). Two specific targets exhibited significantly different volumes of pneumocephalus: the bed nucleus of the stria terminalis with lower volumes (p < 0.001) and the posterior hypothalamus with higher volumes (p = 0.011). MER, time, and other parameters analyzed failed to reach statistical significance. Operative time and use of intraoperative MER are not significant predictors of pneumocephalus during DBS. Air entry is greater for bilateral surgeries and may be also influenced by the specific stimulated target.

Fluorescein sodium-guided resection of a cerebellar lymphoma: case report and literature review.

We report on a patient, who underwent the resection of a cerebellar primary central nervous system lymphoma and was administered intraoperative fluorescein sodium to improve the visualization of the tumor and guide surgery. Low-dosage fluorescein was administered prior to opening the dura so to distinguish contrast-enhanced lymphomatous tissue from the surrounding unenhanced brain cerebellar parenchyma. Intraoperatively, the tumor was indistinguishable from cerebellar parenchyma under the white light, however, after the administration of low-dose intravenous fluorescein, it appeared brightly fluorescent under yellow light, and was safely resected. Our protocol of administration allowed for the sampling of the pathological tissue while at the same time avoiding neurological damage. The fluorescein-guided technique for the resection of primary central nervous system lymphomas has only been rarely described, as surgical excision of such tumors is rarely indicated. Starting from our case, we review and discuss the pertinent literature. Furthermore, an intraoperative video detail is provided.

A cervical solitary fibrous tumor with intramedullary invasion.

Solitary fibrous tumor is a tumor originating from the mesenchymal cells, which occurrence in the central nervous system is extremely rare and was described in few patients as to yet. We report on a 53-years old male patient presenting with right upper limb radicular pain and ipsilateral limbs paresis, who was diagnosed with a cervical spinal lesion which, after surgical resection, resulted to be a solitary fibrous tumor (SFT). We discuss imaging, clinical and histopathological findings to allow considering this tumor early in the differential diagnosis.

Pros of the contralateral (over-the-top) approach to intra/extraforaminal lumbar disc herniations at the L5-S1 level.

Background: Minimally invasive approaches to intra/extraforaminal lumbar disc herniations offer the benefit of less bone removal and reduced nerve root manipulation at the L5-S1 level. Moreover, the potential to better preserve stability. Methods: Here, we summarized the efficacy of the contralateral approach to intraforaminal/extraforaminal lumbar disc herniations particularly focusing on the L5-S1 level. Variables studied included the level of these disc herniations, their locations within the foramina, and the anatomy of the facet joints. Results: A major "pro" for the contralateral interlaminar procedure at the L5-S1 level is that it does not require facet joint removal, or with a spondylotic facet, <30% joint excision, to directly visualize the intraforaminal/ extraforaminal nerve root. It, therefore, reduces the risk of creating iatrogenic instability, while offering a higher certitude of adequate nerve root visualization, decompression, and safer disc removal. Conclusion: The contralateral interlaminar approach is more suitable for all types of intra/extraforaminal disc herniations at the L5/S1 level. The most specific benefit of this approach is its avoidance of disruption/significant removal (i.e., <30%) of the facet joint to adequately expose the foraminal L5 nerve root, and more safely remove the intra/extraforaminal disc herniation.

Intraoperative mobile computed tomography in deep brain stimulation: Comparison between Airo CT and O-arm CT.

Background: A new intraoperative mobile device, called Airo computed tomography (CT), is becoming increasingly used in surgery adding to the current most widespread intraoperative imaging in form of the O-arm CT device. Intraoperative CT imaging has the advantage to reduce the discomfort derived from the patient's transfer from the operative room to the radiological unit and also the time of control or time of reposition in cases of lead misplacement. This is the first rapport on Airo CT device application in DBS surgery. Methods: In our retrospective study, we have evaluated 52 patients who had DBS from October 2020 to November 2021. All patients underwent a preoperative brain magnetic resonance imaging (MRI) and a stereotactic brain CT scan. We performed an intraoperative CT scan with the Airo device. Images were subsequently transferred to the neuronavigation system (BrainLab cranial software) and merged with preoperative planning images to confirm correct position of leads. Five aspects were compared: patient and surgeon comfort, surgical planning, parenchymal visualization, radioscopic lead visualization, and costs. Results: Both imaging devices are easy-to-use, precise, and safe and have their pros and cons. Conclusion: This is the first study reporting on CT-Airo application in DBS. We advise that if only DBS is considered, the O-arm application might be more suitable. If in addition to DBS cranial surgery is performed, the Airo device is more suitable.

A case of treatment-resistant bipolar depression and comorbid OCD treated with deep brain stimulation of the medial forebrain bundle: 5 years follow-up results.

Limited though promising evidence exists on the efficacy of Deep Brain Stimulation (DBS) of the Medial Forebrain Bundle (MFB) in otherwise intractable patients with Major Depression and Obsessive-Compulsive Disorder (OCD). Herein, we present acute and follow-up results (up to 5 years) of a 42 year old man with a diagnosis of treatment-resistant Bipolar Depression (BD) and comorbid OCD, successfully treated with DBS of the MFB. Regular follow-up visits with psychometric evaluations highlighted a considerable improvement of patient's depressive and OC symptoms at 5 years from implant. According to the limited, reported experience, we support the efficacy and tolerability of DBS of the MFB as a promising intervention in patients with treatment-resistant BD and comorbid OCD, with specific emphasis on the long-term outcome.

Thalamic Local Field Potentials Are Related to Long-Term DBS Effects in Tourette Syndrome.

Background: Local field potential (LFP) recordings helped to clarify the pathophysiology of Tourette syndrome (TS) and to define new strategies for deep brain stimulation (DBS) treatment for refractory TS, based on the delivery of stimulation in accordance with changes in the electrical activity of the DBS target area. However, there is little evidence on the relationship between LFP pattern and DBS outcomes in TS. Objective: To investigate the relationship between LFP oscillations and DBS effects on tics and on obsessive compulsive behavior (OCB) comorbidities. Methods: We retrospectively analyzed clinical data and LFP recordings from 17 patients treated with DBS of the centromedian-parafascicular/ventralis oralis (CM-Pf/VO) complex, and followed for more several years after DBS in the treating center. In these patients, LFPs were recorded either in the acute setting (3-5 days after DBS electrode implant) or in the chronic setting (during impulse generator replacement surgery). LFP oscillations were correlated with the Yale Global Tic Severity Scale (YGTSS) and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) collected at baseline (before DBS surgery), 1 year after DBS, and at the last follow-up available. Results: We found that, at baseline, in the acute setting, the power of the oscillations included in the 5-15-Hz band, previously identified as TS biomarker, is correlated with the pathophysiology of tics, being significantly correlated with total YGTSS before DBS (Spearman's ρ = 0.701, p = 0.011). The power in the 5-15-Hz band was also correlated with the improvement in Y-BOCS after 1 year of DBS (Spearman's ρ = -0.587, p = 0.045), thus suggesting a relationship with the DBS effects on OCB comorbidities. Conclusions: Our observations confirm that the low-frequency (5-15-Hz) band is a significant biomarker of TS, being related to the severity of tics and, also to the long-term response on OCBs. This represents a step toward both the understanding of the mechanisms underlying DBS effects in TS and the development of adaptive DBS strategies.

Anterior cervical spine surgical complications: Safety comparison between teacher and student.

BACKGROUND: Anterior cervical surgery has a widespread use. Despite its popularity, this surgery can lead to serious and life-threatening complications, and warrants the attention of skilled attending spinal surgeons with many years of experience. METHODS: We retrospectively evaluated postoperative complications occurring in 110 patients who underwent anterior cervical surgery (anterior cervical discectomy without fusion, anterior cervical discectomy and fusion, and anterior cervical disc arthroplasty) between 2013 and 2020. These operations were performed by an either an attending surgeon with 30 years' experience versus a novice neurosurgeon (NN) with <5 years of training with the former surgeon. Complications were variously identified utilizing admission/discharge notes, surgical reports, follow-up visits, and phone calls. Complications for the two groups were compared for total and specific complication rates (using the Pearson's Chi-square and Fisher's test). RESULTS: The total cumulative complication rate was 15.4% and was not significantly different between the two cohorts. The most frequent postoperative complication was dysphagia. Notably, there were no significant differences in total number of postoperative instances of dysphagia, dysphonia, unintended durotomy, hypoasthenia, and hypoesthesia; the only difference was the longer operative times for NNs. CONCLUSION: Surgeons' years of experience proved not to be a critical factor in determining complication rates following anterior cervical surgery.

Cervical Spondylotic Myelopathy with Ossification of Posterior Longitudinal Ligament: Which Is the Most Suitable Surgical Procedure? A Technical Note.

INTRODUCTION: Anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) are widely performed to resolve anterior cervical spine compression. The main purpose of the different surgical techniques is to obtain an adequate decompression of the spinal cord and nerve roots, preserving spinal stability like in oblique corpectomy or leading to a final solid construct to achieve arthrodesis. TECHNICAL NOTE: We describe a surgical procedure for treating cervical spondylotic myelopathy(CSM) with ossification of the posterior longitudinal ligament (OPLL) at the level of C3-C4 and C4-C5. A double level discectomy C3-C4 and C4-C5 and selective posterior wedge corpectomy of C3, C4, and C5 were performed. Two cages (Zero-P VA) at C3-C4 and C4-C5 were positioned to obtain segmental stability and arthrodesis. An extended anterior cervical canal decompression was obtained and confirmed by postsurgical CT scan. At 15 months, dynamic X-ray showed fusion, and cervical magnetic resonance imaging (MRI) showed evidence of spinal canal decompression. CONCLUSIONS: Anterior cervical discectomy followed by selective wedge corpectomy appears to be a safe and effective technique for anterior spinal cord compression extending above and below the intervertebral disc space.

Degenerative Lumbar Stenosis Surgery: Predictive Factors of Clinical Outcome-Experience with 1001 Patients.

BACKGROUND: Degenerative lumbar spinal stenosis (DLSS) carries a high risk of morbidity and represents a financial burden to society. A late diagnosis can lead to severe disability. Although lumbar decompressive surgery has been widely used worldwide, the proper preoperative factors to define the ideal candidates for decompression are missing. METHODS: A total of 1001 patients who had undergone decompressive surgery from 2012 to 2019 for DLSS were screened for the presence of 9 clinical and radiological parameters. For all cases, the differences between the baseline and postoperative Oswestry disability index were calculated and the results categorized as 5 different classes (ranging from very poor outcomes to excellent outcomes) according to the specific scores. Generalized ordinal logistic regression was then used to analyze the significance of the 9 parameters (coded as dummy variables) in predicting the outcome as measured by Oswestry disability index improvement after surgery. RESULTS: Of the 9 parameters, 8 were found to be significant predictors. The radiological grade of compression was the strongest, followed by polyneuropathy, obesity, symptom duration, gait autonomy, radicular deficits, American Society of Anesthesiologists score, and level of surgery. In contrast, previous back surgery was not predictive of the outcome. CONCLUSIONS: Our findings have indicated that the ideal candidate for surgery will have the following preoperative characteristics: Schizas grade D, no signs of peripheral polyneuropathy, body mass index <30 kg/m2, symptom duration of <2 years, gait autonomy <100 m, no radicular deficits, 1 level of stenosis, and an American Society of Anesthesiologists score of 1, 2, or 3.

Pre-dopa Deep Brain Stimulation: Is Early Deep Brain Stimulation Able to Modify the Natural Course of Parkinson's Disease?

Deep brain stimulation (DBS) is an established therapy for the management of Parkinson's disease (PD). However, DBS is indicated as the disease progresses and motor complications derived from pharmacological therapy arise. Here, we evaluate the potential of DBS prior to levodopa (L-Dopa) in improving quality of life (QoL), challenging the state of the art for DBS therapy. We present data on clinical manifestation, decision finding during early indication to DBS, and trajectories after DBS. We further discuss current paradigms for DBS and hypothesize on possible mechanisms. Six patients, between 50 and 67 years old, presenting at least 5 years of PD symptoms, and without L-Dopa therapy initiation, received subthalamic nucleus (STN) DBS implantation. In the six PD cases, indication for DBS was not driven by motor complications, as supported by current guidelines, but by relevant QoL impairment and patient's reluctance to initiate L-Dopa treatment. All patients treated with STN-DBS prior to L-Dopa presented improvement in motor and non-motor symptoms and significant QoL improvement. All patients reduced the intake of dopamine agonists, and five are currently free from L-Dopa medication, with no reported adverse events. We introduce a multicenter observational study to investigate whether early DBS treatment may affect the natural course of PD. Early application of DBS instead of L-Dopa administration could have a pathophysiological basis and be prompted by a significant incline on QoL through disease progression; however, the clinical value of this proposed paradigm shift should be addressed in clinical trials aimed at modulating the natural course of PD.

Tailored therapy: Surgical and radiosurgical treatment for two distinct myxopapillary ependymomas in the same patient. A case report.

Myxopapillary ependymomas are low grade neoplasms, which originate mostly from the medullary conus, cauda equina and the filum terminale. To date the principal treatment is surgical, total- or subtotal removal (GTR or STR), which can be associated with adjuvant radiotherapy. We report a patient with two tumor locations, one larger tumor at the L3 to S1 level and a smaller S2-S3 localized lesion. The patient was treated successfully with a combined approach of GTR of L3-S1 lesion and radiosurgical treatment of S2-S3 lesion.

Deep Brain Stimulation for Gilles de la Tourette Syndrome: Toward Limbic Targets.

Gilles de la Tourette syndrome (GTS) is a complex neurodevelopmental disorder characterized by tics and, frequently, psychiatric and behavioral comorbidities. Above all, obsessive compulsive disorder/behavior (OCD/OCB) influences the clinical picture and has a severe impact on quality of life, eventually more than the tics themselves. Deep brain stimulation (DBS) is an effective therapy in selected, refractory cases. Clinical response to DBS may vary according to the clinical picture, comorbidities, and to the anatomical target. This retrospective study compares the results obtained from DBS in the ventralis oralis/centromedian-parascicular nucleus of the thalamus (Voi-Cm/Pf) (41 patients) and antero-medial Globus Pallidus internus (am-GPi) (14 patients), evaluating clinical response over time by means of Yale Global Tic Severity Scale (YGTSS) and Yale-Brown Obsessive-Compulsive Scale (YBOCS) scores over a period of 48 months. A significant and stable improvement in the YGTSS and YBOCS has been obtained in both groups (p < 0.001). There was a significant difference in YBOCS improvement over time between the am-GPi group and the Voi-Cm/Pf group, indicating a better and faster control of OCD/OCB symptoms in the former group. The ratio of hardware removal was 23% and limited to 13 patients in the Voi-Cm/Pf group. These results confirm that DBS is an effective therapy in treating GTS and suggest that the am-GPi might be superior to Voi-Cm/Pf in alleviating comorbid OCD/OCB.

Hydrocephalus after Deep Brain Stimulation for Parkinson's Disease.

A fearsome complication of deep brain stimulation (DBS) constitutes intracranial hemorrhage. Incidence rates vary between 0.5% and 5%, with 1.1% of cases resulting in permanent deficit or death. Intracranial hemorrhage can present asymptomatically or result in fatal outcome. A rare complication in this setting is acute hydrocephalus due to obstruction of the cerebrospinal fluid flow. This complication might have catastrophic consequences resulting in death in a few hours if not an external ventricular drainage promptly is placed. We report a patient with acute hydrocephalus due to intraventricular hemorrhage after the DBS procedure. Patients should be warned of this complication when informed consent is obtained.

How to Treat Repeated Subdural Hematomas after Lumbar Puncture?

Serious complications following spinal anesthesia (SA) are rare. However, surgeons and neurologist need to be aware that postsurgery headache refractory to conservative treatment or change in headache's characteristics could be due to serious intracranial complications such as a subdural hematoma. Any delay in diagnosis and treatment can be fatal. We report and discuss a case of a patient who suffered repeated subdural bleeds following SA.