Evaluation of the Rotational Stability of Directional Deep Brain Stimulation Leads: A Case Series and Systematic Review.

BACKGROUND: The rotational stability of directional deep brain stimulation leads is a major prerequisite for sustained clinical effects. Data on directional lead stability are limited and controversial. METHODS: We aimed to evaluate the long-term rotational stability of directional leads and define confounding factors in our own population and the current literature. We retrospectively evaluated the orientation of directional leads in patients with available postoperative computed tomography (CT; T1; day of surgery) and an additional postoperative image (T2; CT or rotational fluoroscopy) performed more than 7 days after the initial scan. The potential impact of intracranial air was assessed. We also reviewed the literature to define factors impacting stability. RESULTS: Thirty-six leads were evaluated. The mean follow-up between T1 and T2 was 413.3 (7-1,171) days. The difference in rotation between T1 and T2 was 2.444 ± 2.554 degrees (range: 0-9.0 degrees). The volume of intracranial air did not impact the rotation. The literature search identified one factor impacting the stability of directional leads, which is the amount of twist applied at implantation. CONCLUSION: Directional leads for deep brain stimulation show stable long-term orientation after implantation. Based on our literature review, large amounts of twist during implantation can lead to delayed rotation and should thus be avoided.

Choice of Implantable Pulse Generators for Deep Brain Stimulation: An Overview of Clinical Practice.

INTRODUCTION: The success of deep brain stimulation (DBS) treatment depends on several factors, including proper patient selection, accurate electrode placement, and adequate stimulation settings. Another factor that may impact long-term satisfaction and therapy outcomes is the type of implantable pulse generator (IPG) used: rechargeable or non-rechargeable. However, there are currently no guidelines on the choice of IPG type. The present study investigates the current practices, opinions, and factors DBS clinicians consider when choosing an IPG for their patients. METHODS: Between December 2021 and June 2022, we sent a structured questionnaire with 42 questions to DBS experts of two international, functional neurosurgery societies. The questionnaire included a rating scale where participants could rate the factors influencing their choice of IPG type and their satisfaction with certain IPG aspects. Additionally, we presented four clinical case scenarios to assess preference of choice of IPG-type in each case. RESULTS: Eighty-seven participants from 30 different countries completed the questionnaire. The three most relevant factors for IPG choice were "existing social support," "cognitive status," and "patient age." Most participants believed that patients valued avoiding repetitive replacement surgeries more than the burden of regularly recharging the IPG. Participants reported that they implanted the same amount of rechargeable as non-rechargeable IPGs for primary DBS insertions and 20% converted non-rechargeable to rechargeable IPGs during IPG replacements. Most participants estimated that rechargeable was the more cost-effective option. CONCLUSION: This present study shows that the decision-making of the choice of IPG is very individualized. We identified the key factors influencing the physician's choice of IPG. Compared to patient-centric studies, clinicians may value different aspects. Therefore, clinicians should rely not only on their opinion but also counsel patients on different types of IPGs and consider the patient's preferences. Uniform global guidelines on IPG choice may not represent regional or national differences in the healthcare systems.

Choroidal artery ischemic events after temporal lobe epilepsy surgery: clinical outcome, quality of life, and surgical pitfalls.

OBJECTIVE: Ischemic events within the territory of the choroidal artery are an important cause of morbidity after temporal lobe epilepsy (TLE) surgery. The aim of the present study was to evaluate the rate of these ischemic events, their clinical presentation, and impact on patients' health-related quality of life (HRQoL) after TLE surgery. METHODS: Four hundred twenty-two consecutive patients undergoing temporal resections for drug-resistant TLE were retrospectively analyzed. All patients underwent presurgical multidisciplinary assessment using a standard protocol comprising clinical, neuroradiological, neuropsychological, and EEG data. Postoperative complications with corresponding imaging, neurological deficits, and disease-specific HRQoL questionnaires were evaluated. RESULTS: The overall complication rate was 7.8% (n = 33). Fourteen patients (3.3%) suffered from ischemic events causing 6 permanent motor deficits, 3 with permanent aphasias, and 6 visual field defects that exceeded quadrantanopia. In 8 patients with anterior choroidal artery infarction, accounting for 57% of all ischemic events, infarction volume correlated positively with the occurrence of new permanent neurological deficits (8666 vs 1692 mm3, p = 0.032). Despite the occurrence of ischemic events, HRQoL improved in 71% of patients. However, infarction volume showed a negative correlation trend with HRQoL (Pearson's r = -0.390, p = 0.094). There was a trend toward increased risk for ischemic events in patients who underwent selective amygdalohippocampectomy compared to patients who underwent anterior temporal lobectomy or temporal lesionectomy (RR 0.96, 95% CI 0.93-0.99, p = 0.08). CONCLUSIONS: Choroidal artery infarctions are rare but relevant complications after TLE surgery, presenting with variable clinical courses ranging from devastating neurological deterioration to complete recovery. Despite the occurrence of postoperative infarction, most patients report improvement of HRQoL after TLE surgery. This study showed that the type of surgery appears to modulate the risk for these ischemic events.

Cumulative surgical morbidity in patients with multiple cerebellar and medullary hemangioblastomas.

OBJECTIVE: Patients affected with von Hippel-Lindau disease often develop multiple hemangioblastomas in the cerebellum and spinal cord. Timing of surgical intervention is difficult and depends largely on the anticipated surgical morbidity. However, data regarding surgical outcome after multiple cerebellar and medullary surgeries are scarce. Our objective was to evaluate cumulative surgical morbidity in patients operated on multiple cerebellar and medullary hemangioblastomas and to deduce recommendations for treatment. METHODS: We performed a retrospective analysis for a consecutive cohort of von Hippel-Lindau patients with surgical treatment of at least two cerebellar and/or medullary hemangioblastomas. Pre- and postoperative functional grades were reviewed in patients' files and compared by Modified Ranking Scale (cerebellar surgeries) or by Modified McCormick Score (medullary surgeries). RESULTS: Thirty-six patients were surgically treated for at least two cerebellar hemangioblastomas (12 patients), at least two medullary hemangioblastomas (19 patients) or at least two hemangioblastomas in both locations (5 patients). Fourthy-eight cerebellar and 80 medullary procedures were performed in total. On average, multiple cerebellar surgeries caused no clinical deterioration, whereas multiple medullary surgeries led to a slight cumulative deterioration of postoperative functional grades. The severity of this deterioration did not correlate to the number of performed medullary surgeries. CONCLUSION: Resection of multiple cerebellar hemangioblastomas is not associated with cumulative morbidity. Although there is a certain cumulative surgical morbidity caused by medullary surgeries, its extent does not increase with the number of performed surgeries. Microsurgical removal of asymptomatic tumors with radiographic progression can also be considered for patients with multiple tumors and previous surgeries.

How Safe Is Minimally Invasive Transforaminal Lumbar Interbody Fusion for Octogenarians?: A Perioperative Complication Analysis.

BACKGROUND: Technical advances in minimally invasive spine surgery have reduced blood loss, access trauma, and postoperative length of stay. However, operating on the susceptible group of octogenarians still poses a dilemma because of a plethora of age-related comorbidities. The aim of this study was to investigate the safety of minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) in octogenarians. METHODS: We conducted a retrospective single-center study of all patients over 80 years of age who, between March 2009 and February 2014, had undergone MIS TLIF. The primary outcome was recorded major and minor complications within 30 days of surgery. RESULTS: Twenty-one patients with an average age of 84.1 ± 2.7 years underwent MIS TLIF in 31 levels for degenerative lumbar disk disease with intolerable pain after failure of conservative treatment. Of the patients, 33.3% showed no perioperative complications. In the remaining 66.7%, 6 major complications and 24 minor complications occurred within 30 days of surgery. Two of these patients died within 30 days of surgery because of sepsis and pulmonary embolism (mortality rate 9.5%). CONCLUSIONS: Our study spotlighted the susceptible group of octogenarians and evaluated the safety of MIS TLIF. The perioperative morbidity for octogenarians undergoing MIS TLIF is substantial and even higher than for patients over 65 years of age. Two thirds of patients in this subgroup suffer at least 1 complication. The 30-day mortality rate was 9.5%. Therefore, it is advisable for these patients to exploit all available conservative options prior to surgery.

Minimally invasive resection and vertebroplasty for an osteolytic C-1 metastasis of malignant meningioma: case report.

Malignant meningiomas are a rare but aggressive subset of intracranial meningiomas leading to a very limited life expectancy. The occurrence of spinal metastases in these tumors is an even rarer event. The described patient had an intracranial malignant meningioma and developed a symptomatic osteolytic contrast-enhancing lesion in the left C-1 lateral mass suspicious for metastasis. The authors performed a minimally invasive posterior resection of the lesion with vertebroplasty of C-1. Histopathology verified metastasis of the malignant meningioma. The surgical procedure resulted in prompt and permanent pain reduction until the patient died 18 months later. Given the very limited life expectancy in this case, the authors did not consider occipitocervical fusion because of their desire to preserve the range of motion of the head. Therefore, they suggest minimally invasive tumor resection and vertebroplasty in selected palliative tumor patients.

Surgeon, staff, and patient radiation exposure in minimally invasive transforaminal lumbar interbody fusion: impact of 3D fluoroscopy-based navigation partially replacing conventional fluoroscopy: study protocol for a randomized controlled trial.

BACKGROUND: Some symptomatic degenerative conditions of the lumbar spine may be treated with spinal fusion if conservative treatment has failed. The minimally invasive technique of transforaminal lumbar interbody fusion (MIS TLIF) is increasingly used but has been found to generate increased radiation exposure to the patient and staff. Modern three-dimensional (3D) C-arm devices are capable of providing conventional two-dimensional fluoroscopic images (x-rays) as well as 3D image sets for intraoperative navigation. This study was designed to compare the radiation exposure between these two intraoperative imaging techniques in MIS TLIF procedures. METHODS: This study is a randomized controlled trial. Forty participants scheduled to undergo monosegmental MIS TLIF will be recruited and randomly allocated to one of two groups with respect to the applied intraoperative imaging technique: conventional fluoroscopy (FLUORO group) and 3D fluoroscopy-based navigation combined with conventional fluoroscopy (NAV group). Furthermore, patients scheduled to undergo bisegmental MIS TLIF during the recruitment period for monosegmental MIS TLIF will be assessed for eligibility and will be randomly assigned separately. The primary endpoint is the radiation exposure to the surgeon and is measured by dosimeter readings. Secondary endpoints are the radiation exposure to the assistant surgeon, scrub nurse, anesthetist, patient, and C-arm as well as radiation exposure in relation to the body mass index of the patient. DISCUSSION: Results of this randomized study will help to compare the radiation exposure to the operating staff and patient during MIS TLIF procedures using conventional fluoroscopy versus 3D fluoroscopy-based navigation combined with conventional fluoroscopy. Furthermore, recommendations regarding the appropriate use of the investigated intraoperative imaging techniques will be made to improve radiation protection and to reduce radiation exposure. TRIAL REGISTRATION: Registration number of the German Clinical Trials Register: DRKS00004514 . Registration date: 11 August 2012.