Clinical Outcome in Patients with Large Sinonasal Tumors with Intracranial Extension.

Objectives Malignant tumors of the sinonasal cavities with extension to the frontal skull base are rare and challenging pathologies. Combined-approach surgery using a frontobasal craniotomy and endoscopic sinus surgery with reconstruction of the anterior skull base followed by adjuvant radiotherapy is a preferred treatment strategy in selected cases. Morbidity and mortality rates are high in this population. We aim to add our experience to the current literature. Design We performed a retrospective cross-sectional single center study of the long-term clinical outcome in a tertiary university referral hospital in the Netherlands between 2010 and 2021. Descriptive statistics and frequency distributions were performed Participants Patient, tumor, treatment, complications and survival characteristics of eighteen consecutive patients were extracted from the electronic health records. Main Outcome Measures The primary outcome measures are progression free survival, overall survival and complication rate. Results Eighteen consecutive patients were included with a mean age of 61 (SD ± 10) years (range 38-80); ten males and eight females. Gross total resection was achieved in 14 (77%) patients. Eleven (61%) patients underwent local radiotherapy, one (5%) chemotherapy and three (17%) a combination of both. Mean follow-up duration was 49 months (range 3 - 138). Three (17%) patients died in hospital due to post-operative complications. Six (33%) patients died during follow-up due to disease progression. Mean progression-free survival was 47 months (range 0 - 113). Conclusion In conclusion, the overall survival was 50% for this group of patients with large sinonasal tumors. Progressive disease affects survival rate severely. Surgical complications were seen in five (28%) patients. Radiotherapy is associated with high complication rates. Radiation necrosis was a serious complication in two patients and could be treated with high dose steroids.

Skull-Base Chondrosarcoma: A Systematic Review of the Role of Postoperative Radiotherapy.

Surgery and radiotherapy are key elements to the treatment of skull-base chondrosarcomas; however, there is currently no consensus regarding whether or not adjuvant radiotherapy has to be administered. This study searched the EMBASE, Cochrane, and PubMed databases for clinical studies evaluating the long-term prognosis of surgery with or without adjuvant radiotherapy. After reviewing the search results, a total of 22 articles were selected for this review. A total of 1388 patients were included in this cohort, of which 186 received surgery only. With mean follow-up periods ranging from 39.1 to 86 months, surgical treatment provided progression-free survival (PFS) rates ranging from 83.7 to 92.9% at 3 years, 60.0 to 92.9% at 5 years, and 58.2 to 64.0% at 10 years. Postoperative radiotherapy provides PFS rates ranging between 87 and 96.2% at 3 years, 57.1 and 100% at 5 years, and 67 and 100% at 10 years. Recurrence rates varied from 5.3% to 39.0% in the surgery-only approach and between 1.5% and 42.90% for the postoperative radiotherapy group. When considering prognostic variables, higher age, brainstem/optic apparatus compression, and larger tumor volume prior to radiotherapy were found to be significant factors for local recurrence.

Skull Base Tumors: The Equilibrium between Curation and Preservation.

Tumors located at the skull base constitute a particular challenge for medical teams [...].

Subclassification of the Koos grade 2 vestibular schwannoma into 2a and 2b for individualized patient care: A validity and reliability study.

OBJECTIVE: Vestibular schwannoma (VS) growth of ≥2 mm during serial MRI observation, irrespective of size, is the benchmark for treatment initiation in almost all centers. Although the probability of less optimal outcomes significantly increases in VS closer to the brainstem, early intervention does not improve long-term quality of life. Moving beyond the recommendation of definitive treatment for all VS after detected growth, we subclassified Koos 2 tumors based on extrameatal extension and relation to the brainstem. The aim of the current study was to evaluate the Koos 2 subclassification's validity and the inter-and intra-rater reliability of the entire Koos classification. METHODS: Six experts, including neurosurgeons, otorhinolaryngologists and radiologists from two tertiary referral centers, classified 43 VS MRI scans. Validity of the Koos 2 subclassification was evaluated by the percentage agreement against the multidisciplinary skull base tumor board management advice. Inter- and intra-rater reliability were calculated using the intraclass correlation coefficient (ICC). RESULTS: Validity was almost perfect in Koos 2a VSs with a 100% agreement and 87.5% agreement for Koos 2b. Inter-rater reliability for all Koos grades was significantly excellent (ICC 0.91; 95%CI 0.866 to 0.944, p= <0.001). Five raters had an excellent intra-rater reliability (ICC > 0.90; p= <0.01) and one rater had a good intra-rater reliability (ICC 0.88; 95% CI 0.742 to 0.949). CONCLUSIONS: Although multiple factors influence decision-making, the classification of Koos 2a and 2b with excellent inter- and intra-rater reliability, can aid in recommending treatment initiation, moving beyond detected tumor growth, aiming to optimize patient centered care.

Characteristics and Clinical Management Strategy of Petrous Apex Cholesterol Granulomas.

Purpose: To evaluate the clinical characteristics of petrous apex cholesterol granulomas (PACG) and assess outcomes after different treatment strategies. Method: A consecutive case series of 34 patients with a PACG. Main outcomes were PACG growth, symptoms, and the outcomes of different treatment strategies: wait-and-scan (WS) and surgical drainage. Results: Thirty-four patients were analyzed; mean follow-up time was 7.1 years. Twenty-one patients (61.7%) showed symptoms, mostly more than one. Most symptoms reported were cranial nerve palsy (58.8%) and headache (35.3%). Twenty-one patients (61.8%) received solely wait-and-scan (WS), and thirteen patients (38.2%) underwent surgery, five of whom (38.5%) after an initial WS period. In the solely WS group, one (4.8%) developed new symptoms, and two (9.5%) reported symptom progression despite a stable granuloma size. Two (9.5%) showed granuloma growth on follow-up scans without symptom progression. Surgery consisted of drainage. Eleven (84.6%) of these thirteen patients reported partial recovery; one (7.7%) reported no recovery; and one (7.7%) reported full recovery of reported symptoms related to PACG. Among the patients with cranial nerve involvement, 7.7% showed full recovery after surgery; 84.6% showed partial recovery; and 7.7% did not recover. Adverse events occurred in five out of 13 patients who underwent surgery, all with full recovery. Conclusions: This study confirms that PACG are slow-growing lesions with a low risk of adverse events. Solely using wait-and-scan strategy is a safe option for patients without symptoms, with acceptable symptoms without symptom progression, and with asymptomatic growth. Surgical treatment can be considered in patients with symptom progression or symptomatic growth.

Wireless stimulation of the subthalamic nucleus with nanoparticles modulates key monoaminergic systems similar to contemporary deep brain stimulation.

BACKGROUND: Deep brain stimulation (DBS) is commonly used to alleviate motor symptoms in several movement disorders. However, the procedure is invasive, and the technology has remained largely stagnant since its inception decades ago. Recently, we have shown that wireless nanoelectrodes may offer an alternative approach to conventional DBS. However, this method is still in its infancy, and more research is required to characterize its potential before it can be considered as an alternative to conventional DBS. OBJECTIVES: Herein, we aimed to investigate the effect of stimulation via magnetoelectric nanoelectrodes on primary neurotransmitter systems that have implications for DBS in movement disorders. METHODS: Mice were injected with either magnetoelectric nanoparticles (MENPs) or magnetostrictive nanoparticles (MSNPs, as a control) in the subthalamic nucleus (STN). Mice then underwent magnetic stimulation, and their motor behavior was assessed in the open field test. In addition, magnetic stimulation was applied before sacrifice and post-mortem brains were processed for immunohistochemistry (IHC) to assess the co-expression of c-Fos with either tyrosine hydroxylase (TH), tryptophan hydroxylase-2 (TPH2) or choline acetyltransferase (ChAT). RESULTS: Stimulated animals covered longer distances in the open field test when compared to controls. Moreover, we found a significant increase in c-Fos expression in the motor cortex (MC) and paraventricular region of the thalamus (PV-thalamus) after magnetoelectric stimulation. Stimulated animals showed fewer TPH2/c-Fos double-labeled cells in the dorsal raphe nucleus (DRN), as well as TH/c-Fos double-labeled cells in the ventral tegmental area (VTA), but not in the substantia nigra pars compacta (SNc). There was no significant difference in the number of ChAT/ c-Fos double-labeled cells in the pedunculopontine nucleus (PPN). CONCLUSIONS: Magnetoelectric DBS in mice enables selective modulation of deep brain areas and animal behavior. The measured behavioral responses are associated with changes in relevant neurotransmitter systems. These changes are somewhat similar to those observed in conventional DBS, suggesting that magnetoelectric DBS might be a suitable alternative.

A case report of an intra-optic recurrent craniopharyngioma.

A 46-year old female patient presented with a left-sided superior temporal quadrantanopia due to a recurrent craniopharyngioma. The location of the recurrence was unusual. Imaging showed an enlarged left optic nerve, suggestive of a recurrent intra-optic craniopharyngioma. It was possible to remove the tumour without compromising the visual functions. In this report, we describe the case in further details.

Long-term results of upfront, single-session Gamma Knife radiosurgery for large cystic vestibular schwannomas.

Anecdotally, cystic vestibular schwannomas (cVSs) are regarded to have unpredictable biologic activity with poorer clinical results, and most studies showed a less favorable prognosis following surgery. While stereotactic radiosurgery (SRS) is a well-established therapeutic option for small- to medium-sized VSs, cVSs are often larger, thus making upfront SRS more complicated. The purpose of this retrospective study was to assess the efficacy and safety of upfront SRS for large cVSs. The authors reviewed the data of 54 patients who received upfront, single-session Gamma Knife radiosurgery (GKRS) with a diagnosis of large cVS (> 4 cm3). Patients with neurofibromatosis type 2, multiple VSs, or recurrent VSs and < 24 months of clinical and neuroimaging follow-up were excluded. Hearing loss (48.1%) was the primary presenting symptom. The majority of cVSs were Koos grade IV (66.7%), and the most prevalent cyst pattern was "mixed pattern of small and big cysts" (46.3%). The median time between diagnosis and GKRS was 12 months (range, 1-147 months). At GKRS, the median cVS volume was 6.95 cm3 (range, 4.1-22 cm3). The median marginal dose was 12 Gy (range, 10-12 Gy). The mean radiological and clinical follow-up periods were 62.2 ± 34.04 months (range, 24-169 months) and 94.9 ± 45.41 months (range, 24-175 months), respectively. At 2, 6, and 12 years, the tumor control rates were 100%, 95.7%, and 85.0%, respectively. Tumor shrinkage occurred in 92.6% of patients (n = 50), tumor volume remained stable in 5.6% of patients (n = 3), and tumor growth occurred in 1.9% of patients (n = 1). At a median follow-up of 53.5 months, the pre-GKRS tumor volume significantly decreased to 2.35 cm3 (p < 0.001). While Koos grade 3 patients had a greater possibility of attaining higher volume reduction, "multiple small thick-walled cyst pattern" and smaller tumor volumes decreased the likelihood of achieving higher volume reduction. Serviceable hearing (Gardner-Robertson Scale I-II) was present in 16.7% of patients prior to GKRS and it was preserved in all of these patients following GKRS. After GKRS, 1.9% of patients (n = 1) had new-onset trigeminal neuralgia. There was no new-onset facial palsy, hemifacial spasm, or hydrocephalus. Contrary to what was believed, our findings suggest that upfront GKRS seems to be a safe and effective treatment option for large cVSs.

A rare complication after vestibular schwannoma surgery: Neurogenic pulmonary edema.

Background: In our center, large vestibular schwannoma (VS) is typically managed by a planned partial resection through the translabyrinthine route. Here, we report on a rare complication of VS surgery and severe neurogenic pulmonary edema. Case Description: A 33-year-old male was referred to our skull-base center with a large VS. A planned partial resection was performed. The surgery was without complications and the patient showed good recovery without facial nerve dysfunction. In the evening of the 2nd day after surgery, the patient showed rapid neurological deterioration, accompanied by cardiac arrest. After the patient was resuscitated, a computed tomography (CT) was made, which showed generalized (infra- and supratentorial) brain edema and hematoma in the resection cavity. Despite rapid removal of the hematoma, there was no change in the neurological situation. The next CT scan showed a further increase of brain edema and the patient died eventually. Autopsy revealed generalized lung edema, brain edema, and Hashimoto's thyroiditis. The pathologist diagnosed neurogenic lung edema. Conclusion: Neurogenic lung edema can occur on the 2nd day after surgery and induce rapid deterioration of the patient with massive brain edema.

LIM and SH3 protein 1 (LASP1) differentiates malignant chordomas from less malignant chondrosarcomas.

PURPOSE: Chordomas are malignant tumors that develop along the neuraxis between skull-base and sacrum. Chondrosarcomas show similarities with chordomas, yet show less malignant behavior. LIM and SH3 protein 1 (LASP1) is a cytoskeletal protein known to promote the malignant behavior of tumors. LASP1 was previously identified as a possibly overexpressed protein in a chordoma proteomics experiment. In this study we compare LASP1 expression in chordoma and chondrosarcoma tissue. METHODS: Biopsies of primary tumors were collected from surgically treated chordoma (n = 6) and chondrosarcoma (n = 6) patients, flash-frozen upon collection and collectively analyzed for LASP1 RNA (real-time PCR) and protein expression (western blotting). Additionally, tissue micro array (TMA)-based immunohistochemistry was applied to an archive of 31 chordoma and 1 chondrosarcoma specimen. RESULTS: In chordoma samples, LASP1 mRNA was detected in 4/6 cases and a strong 36 kDa immunoreactive protein band was observed in 4/5 cases. In contrast, 0/6 chondrosarcoma samples showed detectable levels of LASP1 mRNA and only a weak 36 kDa band was observed in 4/5 cases. Immunohistochemical analysis showed LASP1 expression in all chordoma samples, whereas chondrosarcoma specimen did not show immunoreactivity. CONCLUSION: LASP1 is strongly expressed in the majority of chordoma cases and shows low expression in chondrosarcoma tissue. Since LASP1 is known to function as oncogene and regulate cell proliferation in other tumor types, this study implicates a role for LASP1 in chordoma biology. Further studies are warranted to improve understanding of LASP1's expression and functioning within chordoma, both in vitro and in vivo.

Ectopic Recurrence of Skull Base Chordoma after Proton Therapy.

BACKGROUND: Chordoma are rare tumors of the axial skeleton. The treatment gold standard is surgery, followed by particle radiotherapy. Total resection is usually not achievable in skull base chordoma (SBC) and high recurrence rates are reported. Ectopic recurrence as a first sign of treatment failure is considered rare. Favorable sites of these ectopic recurrences remain unknown. METHODS: Five out of 16 SBC patients treated with proton therapy and surgical resection developed ectopic recurrence as a first sign of treatment failure were critically analyzed regarding prior surgery, radiotherapy, and recurrences at follow-up imaging. RESULTS: Eighteen recurrences were defined in five patients. A total of 31 surgeries were performed for primary tumors and recurrences. Seventeen out of eighteen (94%) ectopic recurrences could be related to prior surgical tracts, outside the therapeutic radiation dose. Follow-up imaging showed that tumor recurrence was difficult to distinguish from radiation necrosis and anatomical changes due to surgery. CONCLUSIONS: In our cohort, we found uncommon ectopic recurrences in the surgical tract. Our theory is that these recurrences are due to microscopic tumor spill during surgery. These cells did not receive a therapeutic radiation dose. Advances in surgical possibilities and adjusted radiotherapy target volumes might improve local control and survival.

The Alteration of Neurogenesis and Pathological Markers in Alzheimer's Disease After Deep Brain Stimulation.

Alzheimer's disease (AD) is the most common type of dementia that causes disabilities in memory formation and activities of daily living. Unfortunately, pharmacologic treatments have minimal and short-lasting effects on AD. With the increasing aging population, investigations into therapeutic strategies for AD that lead to a delay in disease progression would significantly reduce the global burden of AD. Deep brain stimulation (DBS) is considered therapeutic for several conditions, such as movement disorders and some psychiatric diseases. Preclinical and clinical studies that used DBS as a treatment modality demonstrate the safety of DBS in AD and suggest potential memory improvements after surgery. Nevertheless, more studies are needed to understand the therapeutic mechanism of DBS. In this review, we summarize studies on DBS in various targets for AD and discuss DBS-induced changes in neurogenesis and pathological markers in AD.

Electrode Fixation with Bone Cement or Stimloc® in Deep Brain Stimulation Surgery: A Comparative Study.

AIM: To examine the postoperative outcomes of electrode fixation using bone cement and Stimloc® in patients with Parkinson?s disease (PD) who underwent subthalamic nucleus (STN) deep brain stimulation (DBS). MATERIAL AND METHODS: Between 2016 and 2018, permanent electrode fixation was performed in 30 patients with PD, of which 15 received bone cement and the remaining 15 received Stimloc®. Data regarding preoperative Unified Parkinson?s Disease Rating Scale (UPDRS) III scores, levodopa equivalent daily dose (LEDD) values, surgery duration, and the fixation technique used were recorded. Brain computed tomography was performed for early postoperative evaluation of pneumocephalus and possible hematoma as well as for the determination of migration 1 year postoperatively. UPDRS III scores and LEDD values were re-evaluated 1 year postoperatively; surgery duration, clinical effectiveness, and complication rates were compared between the two fixation techniques. RESULTS: A statistically significant difference in application time was observed between the two techniques (bone cement: 21 min, Stimloc®: 6 min). After 1 year from surgery, 0.92- and 0.88-mm migrations were observed in the bone cement and Stimloc® groups, respectively. A significant correlation between migration and the pneumocephalus volume was observed in both groups. No differences were observed between the groups regarding infection, migration, pneumocephalus volume, wound erosion, and clinical outcomes. CONCLUSION: Stimloc® is preferred over bone cement for electrode fixation in DBS surgeries as it is associated with shorter application duration; this increases patient comfort and tolerance during awake surgery. Clinical efficacy and complication rates associated with both techniques are similar.

Surgical and Hardware-Related Adverse Events of Deep Brain Stimulation: A Ten-Year Single-Center Experience.

INTRODUCTION: Although deep brain stimulation (DBS) is effective for treating a number of neurological and psychiatric indications, surgical and hardware-related adverse events (AEs) can occur that affect quality of life. This study aimed to give an overview of the nature and frequency of those AEs in our center and to describe the way they were managed. Furthermore, an attempt was made at identifying possible risk factors for AEs to inform possible future preventive measures. MATERIALS AND METHODS: Patients undergoing DBS-related procedures between January 2011 and July 2020 were retrospectively analyzed to inventory AEs. The mean follow-up time was 43 ± 31 months. Univariate logistic regression analysis was used to assess the predictive value of selected demographic and clinical variables. RESULTS: From January 2011 to July 2020, 508 DBS-related procedures were performed including 201 implantations of brain electrodes in 200 patients and 307 implantable pulse generator (IPG) replacements in 142 patients. Surgical or hardware-related AEs following initial implantation affected 40 of 200 patients (20%) and resolved without permanent sequelae in all instances. The most frequent AEs were surgical site infections (SSIs) (9.95%, 20/201) and wire tethering (2.49%, 5/201), followed by hardware failure (1.99%, 4/201), skin erosion (1.0%, 2/201), pain (0.5%, 1/201), lead migration (0.52%, 2/386 electrode sites), and hematoma (0.52%, 2/386 electrode sites). The overall rate of AEs for IPG replacement was 5.6% (17/305). No surgical, ie, staged or nonstaged, electrode fixation, or patient-related risk factors were identified for SSI or wire tethering. CONCLUSIONS: Major AEs including intracranial surgery-related AEs or AEs requiring surgical removal or revision of hardware are rare. In particular, aggressive treatment is required in SSIs involving multiple sites or when Staphylococcus aureus is identified. For future benchmarking, the development of a uniform reporting system for surgical and hardware-related AEs in DBS surgery would be useful.

Multicenter Validation of Individual Preoperative Motor Outcome Prediction for Deep Brain Stimulation in Parkinson's Disease.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN DBS) is an established therapy for Parkinson's disease (PD) patients suffering from motor response fluctuations despite optimal medical treatment, or severe dopaminergic side effects. Despite careful clinical selection and surgical procedures, some patients do not benefit from STN DBS. Preoperative prediction models are suggested to better predict individual motor response after STN DBS. We validate a preregistered model, DBS-PREDICT, in an external multicenter validation cohort. METHODS: DBS-PREDICT considered eleven, solely preoperative, clinical characteristics and applied a logistic regression to differentiate between weak and strong motor responders. Weak motor response was defined as no clinically relevant improvement on the Unified Parkinson's Disease Rating Scale (UPDRS) II, III, or IV, 1 year after surgery, defined as, respectively, 3, 5, and 3 points or more. Lower UPDRS III and IV scores and higher age at disease onset contributed most to weak response predictions. Individual predictions were compared with actual clinical outcomes. RESULTS: 322 PD patients treated with STN DBS from 6 different centers were included. DBS-PREDICT differentiated between weak and strong motor responders with an area under the receiver operator curve of 0.76 and an accuracy up to 77%. CONCLUSION: Proving generalizability and feasibility of preoperative STN DBS outcome prediction in an external multicenter cohort is an important step in creating clinical impact in DBS with data-driven tools. Future prospective studies are required to overcome several inherent practical and statistical limitations of including clinical decision support systems in DBS care.

Genes Predicting Survival of Chordoma Patients.

BACKGROUND: A chordoma is a slow-growing, invasive neoplasm in the neuraxis that is thought to arise from notochordal cells. At 10-year follow-up, the average survival rate is 50%, though individual prognosis varies substantially. We aimed to provide a comprehensive overview of the genes and proteins expressed in these tumors and their prognostic value to facilitate prognostication for patients with chordoma. METHODS: A systematic search of clinical studies that investigated expressed factors related to chordoma survival was performed in PubMed. Data extracted included RNA and protein expression data and prognostic value (in terms of overall survival, progression-free survival, disease-free survival, and recurrence-free survival) from univariate and multivariate analyses. RESULTS: This review included 78 original studies that collectively evaluated 134 expressed factors. Of these molecular factors, 96 by univariate analysis and 32 by multivariate analysis had a predictive value for patient survival. Of the molecular factors studied in multivariate analyses, 26 factors had a negative effect while 6 had a positive effect on patient survival. CONCLUSIONS: Identification of molecular factors that are associated with survival contributes to better prognostication of patients with chordoma. Given the rarity of chordoma, often only univariate analyses can be performed. Robust multivariate analyses are scarcer but provide independently significant prognostic factors. The data presented in this review can aid in prognostication for the individual patient and facilitate the development of targeted therapies.

Deep Brain Stimulation of the Globus Pallidus Internus for Secondary Dystonia: Clinical Cases and Systematic Review of the Literature Regarding the Effectiveness of Globus Pallidus Internus versus Subthalamic Nucleus.

OBJECTIVE: Deep brain stimulation (DBS) is a frequently applied therapy in primary dystonia. For secondary dystonia, the effects can be less favorable. We share our long-term findings in 9 patients with severe secondary dystonia and discuss these findings in the light of the literature. METHODS: Patients who had undergone globus pallidus internus (GPi)-DBS for secondary dystonia were included. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores, clinical improvement rates, follow-up periods, stimulation parameters and the need for internal pulse generator replacements were analyzed. The PubMed and Google Scholar databases were searched for articles describing GPi-DBS and subthalamic nucleus (STN)-DBS only for secondary dystonia cases. Keywords were "dystonia," "deep brain stimulation," "GPi," "dystonia," "deep brain stimulation," and "STN." RESULTS: A total of 9 secondary dystonia patients (5 male, 4 female) had undergone GPi-DBS with microelectrode recording in our units. The mean follow-up period was 29 months. The average BFMDRS score was 58.2 before the surgery, whereas the mean value was 36.5 at the last follow-up of the patients (mean improvement, 39%; minimum, 9%; maximum, 63%). In the literature review, we identified 264 GPi-DBS cases (mean follow-up, 19 months) in 72 different articles about secondary dystonia. The mean BFMDRS improvement rate was 52%. In 146 secondary dystonia cases, reported in 19 articles, STN-DBS was performed. The average follow-up period was 20 months and the improvement in BFMDRS score was 66%. CONCLUSIONS: Although GPi-DBS has favorable long-term efficacy and safety in the treatment of patients with secondary dystonia, STN seems a promising target for stimulation in patients with secondary dystonia. Further studies including a large number of patients, longer follow-up periods, and more homogenous patients are necessary to establish the optimal target for DBS in the management of secondary dystonias.

Impact of Procedural Sedation on the Clinical Outcome of Microelectrode Recording Guided Deep Brain Stimulation in Patients with Parkinson's Disease.

BACKGROUND: Subthalamic nucleus (STN) deep brain stimulation (DBS) has become a routine treatment of advanced Parkinson's disease (PD). DBS surgery is commonly performed under local anesthesia (LA) to obtain reliable microelectrode recordings. However, procedural sedation and/or analgesia (PSA) is often desirable to improve patient comfort. The impact of PSA in addition to LA on outcome is largely unknown. Therefore, we performed an observational study to assess the effect of PSA compared to LA alone during STN DBS surgery on outcome in PD patients. METHODS: Seventy PD patients (22 under LA, 48 under LA + PSA) scheduled for STN DBS implantation were included. Dexmedetomidine, clonidine or remifentanil were used for PSA. The primary outcome was the change in Movement Disorders Society Unified Parkinson's Disease Rating Score III (MDS-UPDRS III) and levodopa equivalent daily dosage (LEDD) between baseline, one month before surgery, and twelve months postoperatively. Secondary outcome measures were motor function during activities of daily living (MDS-UPDRS II), cognitive alterations and surgical adverse events. Postoperative assessment was conducted in "on" stimulation and "on" medication conditions. RESULTS: At twelve months follow-up, UPDRS III and UPDRS II scores in "on" medication conditions were similar between the LA and PSA groups. The two groups showed a similar LEDD reduction and an equivalent decline in executive function measured by the Stroop Color-Word Test, Trail Making Test-B, and verbal fluency. The incidence of perioperative and postoperative adverse events was similar between groups. CONCLUSION: This study demonstrates that PSA during STN DBS implantation surgery in PD patients was not associated with differences in motor and non-motor outcome after twelve months compared with LA only.

Effect of Anesthesia on Microelectrode Recordings During Deep Brain Stimulation Surgery: A Narrative Review.

Deep brain stimulation (DBS) is an effective surgical treatment for patients with various neurological and psychiatric disorders. Clinical improvements rely on careful patient selection and accurate electrode placement. A common method for target localization is intraoperative microelectrode recording (MER). To facilitate MER, DBS surgery is traditionally performed under local or regional anesthesia. However, sedation or general anesthesia is sometimes needed for patients who are unable to tolerate the procedure fully awake because of severe motor symptoms, psychological distress, pain, or other forms of discomfort. The effect of anesthetic drugs on MER is controversial but likely depends on the type and dose of a particular anesthetic agent, underlying disease, and surgical target. In this narrative review, we provide an overview of the current literature on the anesthetic drugs most often used for sedation and anesthesia during DBS surgery, with a focus on their effects on MERs.

The association between surgical characteristics and cognitive decline following deep brain stimulation of the subthalamic nucleus in Parkinson's disease.

OBJECTIVE: Despite optimal improvement in motor functioning, both short- and long-term studies have reported small but consistent changes in cognitive functioning following STN-DBS in Parkinson's disease (PD). The aim of the present study was to explore whether surgical characteristics were associated with cognitive decline one year following STN-DBS. METHODS: We retrospectively analyzed 49 PD patients who underwent bilateral STN-DBS. Cognitive change scores were related to the number of microelectrode recording (MER) trajectories, the STN length as measured by MER, and cortical entry points. Regression analyses were corrected for age at surgery, disease duration, education and preoperative levodopa responsiveness. Patients were then divided into a cognitive and non-cognitive decline group for each neuropsychological test and compared regarding demographic and surgical characteristics. RESULTS: One year postoperatively, significant declines were found in verbal fluency, Stroop Color-Word test and Trail Making Test B (TMT-B). Only changes in TMT-B were associated with the coronal entry point in the right hemisphere. The number of MER trajectories and STN length were not associated with cognitive change scores. When comparing the cognitive decline and non-cognitive decline groups, no significant differences were found in surgical characteristics. CONCLUSIONS: The electrode passage through the right prefrontal lobe may contribute to subtle changes in executive function. However, only few patients showed clinically relevant cognitive decline. The use of multiple MER trajectories and a longer STN length were not associated with cognitive decline one year following surgery. From a cognitive point of view, DBS may be considered a relatively safe procedure.