First clinical experience with fractionated intracavitary radioimmunotherapy using [177Lu]Lu-6A10-Fab fragments in patients with glioblastoma: a pilot study

BACKGROUND

Following resection and standard adjuvant radio- and chemotherapy, approved maintenance therapies for glioblastoma are lacking. Intracavitary radioimmunotherapy (iRIT) with 177Lu-labeled 6A10-Fab fragments targeting tumor-associated carbonic anhydrase XII and injected into the resection cavity offers a novel and promising strategy for improved tumor control.

METHODS

Three glioblastoma patients underwent tumor resection followed by standard radio- and chemotherapy. These patients with stable disease following completion of standard therapy underwent iRIT on compassionate grounds. After surgical implantation of a subcutaneous injection reservoir with a catheter into the resection cavity, a leakage test with [99mTc]Tc-DTPA was performed to rule out leakage into other cerebral compartments. IRIT comprised three consecutive applications over three months for each patient, with 25%, 50%, 25% of the total activity injected. A dosimetry protocol was included with blood sampling and SPECT/CT of the abdomen to calculate doses for the bone marrow and kidneys as potential organs at risk.

RESULTS

All three patients presented without relevant leakage after application of [99mTc]Tc-DTPA. Two patients underwent three full cycles of iRIT (592 MBq and 1228 MBq total activity). One patient showed histologically proven tumor progression after the second cycle (526 MBq total activity). No relevant therapy-associated toxicities or adverse events were observed. Dosimetry did not reveal absorbed doses above upper dose limits for organs at risk.

CONCLUSIONS

In first individual cases, iRIT with [177Lu]Lu-6A10-Fab appears to be feasible and safe, without therapy-related side effects. A confirmatory multicenter phase-I-trial was recently opened and is currently recruiting.

The Role of Prolonged Bed Rest in Postoperative Cerebrospinal Fluid Leakage After Surgery of Intradural Pathology-A Retrospective Cohort Study

BACKGROUND

Postoperative cerebrospinal fluid leakage (CSFL) is a feared complication after surgery on intradural pathologies and may cause postoperative complications and subsequently higher treatment costs.

OBJECTIVE

To assess whether prolonged bed rest may lower the risk of CSFL.

METHODS

We performed a retrospective cohort study including patients with intradural pathologies who underwent surgery at our department between 2013 and 2021. Cohorts included patients who completed 3 days of postoperative bed rest and patients who were mobilized earlier. The primary end point was the occurrence of clinically proven CSFL.

RESULTS

Four hundred and thirty-three patients were included (female [51.7%], male [48.3%]) with a mean age of 48 years (SD ±20). Bed rest was ordered in 315 cases (72.7%). In 7 cases (N = 7/433, 1.6%), we identified a postoperative CSFL. Four of them (N = 4/118) did not preserve bed rest, showing no significant difference to the bed rest cohort (N = 3/315; P = .091). In univariate analysis, laminectomy (N = 4/61; odds ratio [OR] 8.632, 95% CI 1.883-39.573), expansion duraplasty (N = 6/70; OR 33.938, 95% CI 4.019-286.615), and recurrent surgery (N = 5/66; OR 14.959, 95% CI 2.838-78.838) were significant risk factors for developing CSFL. In multivariate analysis, expansion duraplasty was confirmed as independent risk factor (OR 33.937, 95% CI 4.018-286.615, P = .001). In addition, patients with CSFL had significant higher risk for meningitis (N = 3/7; 42.8%, P = .001).

CONCLUSION

Prolonged bed rest did not protect patients from developing CSFL after surgery on intradural pathologies. Avoiding laminectomy, large voids, and minimal invasive approaches may play a role in preventing CSFL. Furthermore, special caution is indicated if expansion duraplasty was done.

Prognosis and histology of sporadic synchronous and metachronous meningiomas and comparative analyses with singular lesions

Synchronous or metachronous growth of multiple tumors (≥ 2) is found in up to 20% of meningioma patients. However, biological as well as histological features and prognosis are largely unexplored. Clinical and histological characteristics were retrospectively investigated in 95 patients harboring 226 multiple meningiomas (MMs) and compared with 135 cases of singular meningiomas (SM) using uni- and multivariate analyses. In MM, tumors occurred synchronously and metachronously in 62% and 38%, respectively. WHO grade was intra-individually constant in all but two MMs, and histological subtype varied in 13% of grade 1 tumors. MM occurred more commonly in convexity/parasagittal locations, while SM were more frequent at the skull base (p < .001). In univariate analyses, gross total resection (p = .014) and high-grade histology in MM were associated with a prolonged time to progression (p < .001). Most clinical characteristics and rates of high-grade histology were similar in both groups (p ≥ .05, each). Multivariate analyses showed synchronous/metachronous meningioma growth (HR 4.50, 95% CI 2.26-8.96; p < .001) as an independent predictor for progression. Compared to SM, risk of progression was similar in cases with two (HR 1.56, 95% CI .76-3.19; p = .224), but exponentially raised in patients with 3-4 (HR 3.25, 1.22-1.62; p = .018) and ≥ 5 tumors (HR 13.80, 4.06-46.96; p < .001). Clinical and histological characteristics and risk factors for progression do not relevantly differ between SM and MM. Although largely constant, histology and WHO grade occasionally intra-individually vary in MM. A distinctly higher risk of disease progression in MM as compared to SM might reflect different underlying molecular alterations.

Iatrogenic lumbosacral infiltration with petroleum (hydrodesulfurized heavy) with secondary intrathecal distribution-a case report

Petroleum is commonly used as a solvent, and primary intrathecal administration or secondary diffusion and subsequent clinical management has not been reported. We report the case of a male patient with intrathecal petroleum diffusion following accidental lumbar infiltration. After the onset of secondary myeloencephalopathy with coma and tetraparesis, continuous cranio-lumbar irrigation using an external ventricular and a lumbar drain was established. Cranial imaging revealed distinct supra- and infratentorial alterations. The patient improved slowly and was referred to rehabilitation. Intrathecal petroleum leads to myeloencephalopathy and continuous cranio-lumbar irrigation might be a safe treatment option.

Postoperative surveillance in cranial and spinal tumor neurosurgery: when is this warranted?

OBJECTIVE

The outbreak of COVID-19 and the sudden increase in the number of patients requiring mechanical ventilation significantly affected the management of neurooncological patients. Hospitals were forced to reallocate already scarce human resources to maximize intensive care unit (ICU) capacities, resulting in a significant postponement of elective procedures for patients with brain and spinal tumors, who traditionally require elective postoperative surveillance on ICU or intermediate care wards. This study aimed to characterize those patients in whom postoperative monitoring is required by analyzing early postoperative complications and associated risk factors.

METHODS

All patients included in the analysis experienced benign or malignant cerebral or intradural tumors and underwent surgery between September 2017 and May 2019 at University Hospital Münster, Germany. Patient data were generated from a semiautomatic, prospectively designed database. The occurrence of adverse events within 24 hours and 30 days postoperatively-including unplanned reoperation, postoperative hemorrhage, CSF leakage, and pulmonary embolism-was chosen as the primary outcome measure. Furthermore, reasons and risk factors that led to a prolonged stay on the ICU were investigated. By performing multivariable logistic regression modeling, a risk score for early postoperative adverse events was calculated by assigning points based on beta coefficients.

RESULTS

Eight hundred eleven patients were included in the study. Eleven patients (1.4%) had an early adverse event within 24 hours, which was either an unplanned reoperation (0.9%, n = 7) or a pulmonary embolism (0.5%, n = 4) within 24 hours. To predict the incidence of early postoperative complications, a score was developed including the number of secondary diagnoses, BMI, and incision closure time, termed the SOS score. According to this score, 0.3% of the patients were at low risk, 2.5% at intermediate risk, and 12% at high risk (p < 0.001).

CONCLUSIONS

Postoperative surveillance in cranial and spinal tumor neurosurgery might only be required in a distinct patient collective. In this study, the authors present a new score allowing efficient prediction of the likelihood of early adverse events in patients undergoing neurooncological procedures, thus helping to stratify the necessity for ICU or intermediate care unit beds. Nevertheless, validation of the score in a multicenter prospective setting is needed.

Complex Spinal Dorso-Ventral Stabilization in the Elderly – Is Age a Limiting Factor? Retrospective Case Series of 53 patients

Objective: Medical progress is increasingly confronting us with the question of whether complex surgical spinal care can be performed safely, even in older patients. This study is intended to contribute to the clarification of this question. Methods: 53 patients with a minimum age of 70 years at time of surgery were retrospectively enrolled in a single center setting. All patients were treated with complex dorsoventral instrumentation and corpectomy due to different pathologies. Because of neurological deficits and untreatable pain, no control group of patients could be defined in advanced age by withholding necessary surgery. The ethical committee would not accept this. Results: Most patients benefited from the procedure with regard to pain (97%), sensori-motor deficit (89%), and finally, immobility (82%). The duration of surgery, the amount of transfused red blood cell concentrates, and the length of hospital stay were not predictors of a poor overall outcome. It was shown that the risk of postoperative complications increased due to the number of preoperative secondary diagnoses. Conclusion: Therefore, not the patients’ age alone is of prime importance for individual surgical treatment decisions, but the number of secondary diagnoses plays a more important role. Especially in that older population, patients benefit from surgical therapy; regardless, it could be complex.

Efficacy of decitabine in malignant meningioma cells: relation to promoter demethylation of distinct tumor suppressor and oncogenes and independence from TERT

OBJECTIVE

Chemotherapeutic options for meningiomas refractory to surgery or irradiation are largely unknown. Human telomerase reverse transcriptase (hTERT) promoter methylation with subsequent TERT expression and telomerase activity, key features in oncogenesis, are found in most high-grade meningiomas. Therefore, the authors investigated the impact of the demethylating agent decitabine (5-aza-2'-deoxycytidine) on survival and DNA methylation in meningioma cells.

METHODS

hTERT promoter methylation, telomerase activity, TERT expression, and cell viability and proliferation were investigated prior to and after incubation with decitabine in two benign (HBL-52 and Ben-Men 1) and one malignant (IOMM-Lee) meningioma cell line. The global effects of decitabine on DNA methylation were additionally explored with DNA methylation profiling.

RESULTS

High levels of TERT expression, telomerase activity, and hTERT promoter methylation were found in IOMM-Lee and Ben-Men 1 but not in HBL-52 cells. Decitabine induced a dose-dependent significant decrease of proliferation and viability after incubation with doses from 1 to 10 μM in IOMM-Lee but not in HBL-52 or Ben-Men 1 cells. However, effects in IOMM-Lee cells were not related to TERT expression, telomerase activity, or hTERT promoter methylation. Genome-wide methylation analyses revealed distinct demethylation of 14 DNA regions after drug administration in the decitabine-sensitive IOMM-Lee but not in the decitabine-resistant HBL-52 cells. Differentially methylated regions covered promoter regions of 11 genes, including several oncogenes and tumor suppressor genes that to the authors' knowledge have not yet been described in meningiomas.

CONCLUSIONS

Decitabine decreases proliferation and viability in high-grade but not in benign meningioma cell lines. The effects of decitabine are TERT independent but related to DNA methylation changes of promoters of distinct tumor suppressor genes and oncogenes.

The 30-day readmission rate in neurosurgery-a useful indicator for quality assessment?

BACKGROUND

A shift in how we evaluate healthcare outcomes has driven the introduction of quality indicators as potential parameters to evaluate value-based healthcare delivery. So far, only few studies have been performed evaluating quality indicators in the context of neurosurgery, especially in the European region. The purpose of this study was to evaluate the 30-day readmission rate, identify reasons for readmission regarding the various neurosurgical diagnoses, and discuss the usefulness of this rate as a potential quality indicator.

METHODS

During a 6-year period, a total of 8878 hospitalized patients in our neurosurgical department were retrospectively analyzed and included in this study. Reasons for readmission were identified. Patients' diagnoses and baseline characteristics were obtained in order to identify possible risk factors for readmission.

RESULTS

The 30-day readmission rate was 2.9%. The most common reason for unplanned readmissions were surgical site infections. The reasons for readmissions varied significantly between the different underlying neurosurgical diseases (p < 0.001). Multivariate logistic regression revealed hydrocephalus (OR, 4) and shorter length of stay during index admission (OR, 0.9) as risk factors for readmission.

CONCLUSIONS

We provided an analysis of reasons for readmission for various neurosurgical diseases in a large patient spectrum in Germany. Although readmission rates are easy to track and an attractive tool for quality assessment, the rate alone cannot be seen as an adequate measure for quality in neurosurgery as it lacks a homogenous definition and depends on the underlying health care system. In addition, strategies for risk adjustment are required.

Evaluation of 311 contemporary cases of stereotactic biopsies in patients with neoplastic and non-neoplastic lesions-diagnostic yield and management of non-diagnostic cases

Stereotactic biopsies are an established tool for obtaining diagnosis of unclear brain lesions. However, non-diagnostic biopsies still occur. We aimed to analyze the contemporary diagnostic yield of stereotactic biopsies, predictors for non-diagnostic biopsies, outcome, and follow-up strategy after non-diagnostic biopsy. We conducted a single-center retrospective study of 311 adult patients undergoing stereotactic biopsies due to a newly diagnosed lesion at our department between 2012 and 2018. Patient data regarding comorbidities, presenting symptoms, imaging features, and non-invasive diagnostic procedures were obtained. The overall diagnostic yield was 86.2% and differed significantly between the various suspected diagnosis groups and was the highest when suspecting primary brain tumor compared with non-neoplastic lesions (91.2% vs. 73.3%, p > 0.001). Predicators for non-diagnostic biopsies were small lesion size, lack of contrast-enhancement, presence of sepsis, or underlying hemato-oncological disease. In case of non-diagnostic biopsy, a re-biopsy was performed in 12 cases, revealing a final diagnosis in 75%. In 16 cases, empiric therapy was started based on the suspected underlying disease. Close follow-up was performed in the remaining 15 cases. We showed that stereotactic biopsy is a safe procedure with reasonable diagnostic yield even for non-neoplastic lesions, when non-invasive diagnostic was inconclusive. In addition, we developed treatment recommendations for cases of non-diagnostic biopsies.

Real-time in vivo kinetics of protoporphyrin IX after administration of 5-aminolevulinic acid in meningiomas and comparative analyses with glioblastomas

BACKGROUND

The usefulness of 5-aminolevulinic acid (5-ALA)-mediated fluorescence-guided surgery (FGS) in meningiomas is intensely discussed. However, data about kinetics of 5-ALA and protoporphyrin (Pp) IX in meningiomas are lacking.

METHODS

As the first study so far, we performed longitudinal intraoperative real-time ex situ measurements of fluorescence intensity and PpIX concentrations during FGS of ten benign and two atypical meningiomas. Kinetics were subsequently compared with data from 229 glioblastomas.

RESULTS

Spectroscopy revealed fluorescence (median 2945.65 a.u.) and PpIX accumulation (median 18.31 μg/ml) in all 43 analyzed samples. Fluorescence intensity (2961.50 a.u. vs 118.41 a.u.; p < .001) and PpIX concentrations (18.72 μg/ml vs .98 μg/ml; p < .001) were higher in samples with (N = 30) than without (N = 2) visible intraoperative tumor fluorescence. ROC curve analyses revealed a PpIX cut-off concentration of 3.85 μg/ml (AUC = .992, p = .005) and a quantitative fluorescence cut-off intensity of 286.73 a.u. (AUC = .983, p = .006) for intraoperative visible tumor fluorescence. Neither fluorescence intensity (p = .356) nor PpIX (p = .631) differed between atypical and benign meningiomas. Fluorescence and PpIX peaked 7-8 h following administration of 5-ALA. Meningiomas displayed a higher fluorescence intensity (p = .012) and PpIX concentration (p = .005) than glioblastomas 5-6 h after administration of 5-ALA. Although fluorescence was basically maintained, PpIX appeared to be cleared faster in meningiomas than in glioblastomas.

CONCLUSIONS

Kinetics of PpIX and fluorescence intensity differ between meningiomas and glioblastomas in the early phase after 5-ALA administration. Modification of the timing of drug administration might impact visibility of intraoperative fluorescence and helpfulness of FGS and should be investigated in future analyses.

Risk of tumor recurrence in intracranial meningiomas: comparative analyses of the predictive value of the postoperative tumor volume and the Simpson classification

OBJECTIVE

In meningiomas, the Simpson grading system is applied to estimate the risk of postoperative recurrence, but might suffer from bias and limited overview of the resection cavity. In contrast, the value of the postoperative tumor volume as an objective predictor of recurrence is largely unexplored. The objective of this study was to compare the predictive value of residual tumor volume with the intraoperatively assessed extent of resection (EOR).

METHODS

The Simpson grade was determined in 939 patients after surgery for initially diagnosed intracranial meningioma. Tumor volume was measured on initial postoperative MRI within 6 months after surgery. Correlation between both variables and recurrence was compared using a tree-structured Cox regression model.

RESULTS

Recurrence correlated with Simpson grading (p = 0.003). In 423 patients (45%) with available imaging, residual tumor volume covered a broad range (0-78.5 cm3). MRI revealed tumor remnants in 8% after gross-total resection (Simpson grade I-III, range 0.12-33.5 cm3) with a Cohen's kappa coefficient of 0.7153. Postoperative tumor volume was correlated with recurrence in univariate analysis (HR 1.05 per cm3, 95% CI 1.02-1.08 per cm3, p < 0.001). A tree-structured Cox regression model revealed any postoperative tumor volume > 0 cm3 as a critical cutoff value for the prediction of relapse. Multivariate analysis confirmed the postoperative tumor volume (HR 1.05, p < 0.001) but not the Simpson grading (p = 0.398) as a predictor for recurrence.

CONCLUSIONS

EOR according to Simpson grading was overrated in 8% of tumors compared to postoperative imaging. Because the predictive value of postoperative imaging is superior to the Simpson grade, any residual tumor should be carefully considered during postoperative care of meningioma patients.

Dual labeling with 5-aminolevulinic acid and fluorescein in high-grade glioma surgery with a prototype filter system built into a neurosurgical microscope: technical note

OBJECTIVE

Recent efforts to improve visualization of 5-aminolevulinic acid (5-ALA)–induced protoporphyrin IX (PPIX) fluorescence resulted in a dual-labeling technique, combining it with fluorescein sodium in a prototype setup. Fluorescein identifies regions with blood-brain barrier breakdown in gliomas. However, normally perfused and edematous brain fluoresces unselectively, with strong background enhancement. The aim of this study was to test the feasibility of a novel, integrated filter combination using porphyrins for selective tumor identification and fluorescein for background enhancement.

METHODS

A microscope with a novel built-in filter system (YB 475) for visualizing both fluorescein and 5-ALA–induced porphyrins was used. Resection limits were identified with the conventional BLUE 400 filter system. Six patients harboring contrast ring-enhancing lesions were analyzed.

RESULTS

The complete surgical field could now be illuminated. Fluorescein was helpful for improving background visualization, and enhancing dura, edematous tissue, and cortex. Overlapping regions with both fluorophores harbored merged orange fluorescence. PPIX fluorescence was better visualized, even in areas beyond a normal working distance of approximately 25 cm, where the BLUE 400 filters recognized no or weak fluorescence.

CONCLUSIONS

The novel filter system improved general tissue brightness and background visualization, enhancing fluorescence-guided tumor resection. Furthermore, it appears promising from a scientific perspective, enabling the simultaneous and direct observation of areas with blood-brain barrier breakdown and PPIX fluorescence.

Validating a new generation filter system for visualizing 5-ALA-induced PpIX fluorescence in malignant glioma surgery: a proof of principle study

BACKGROUND

The BLUE 400 filter system (Carl Zeiss Meditec, Oberkochen, Germany) has provided visualization of 5-ALA-induced fluorescence-guided surgery for more than 20 years. Nevertheless, constraints, e.g., limited background discrimination during hemostasis, obstruct fluency of surgery. A novel filter with improved background visualization was developed, requiring validation regarding fluorescence discrimination. The aim of this article is to determine diagnostic accuracy and perception of protoporphyrin IX (PpIX) discrimination of a novel filter system with higher background illumination (BLUE 400 AR) compared with the gold standard, BLUE 400.

METHODS

A surgical microscope equipped with both BLUE 400 and BLUE 400 AR was used. Comparisons were performed on a biological basis and on the visual perception of margins. High-resolution images were compared during and after surgery by senior neurosurgeons. In a predefined biopsy algorithm, four biopsies per patient at tumor margins of PpIX fluorescence and adjacent brain were acquired using BLUE 400 AR only from regions intended for resection and assessed for cell count and density.

RESULTS

Thirty-two patients with malignant gliomas were included in this study. BLUE 400 AR markedly enhanced the brightness of the surgical field, allowing superior discrimination of brain anatomy. A total of 128 biopsies from fluorescence margins were collected. Positive predictive value (PPV) was 98.44% (95% CI, 90.06-99.77%) for malignant glioma. Residual median cell density in non-fluorescent tissue was 13% (IQR 13 to 31). Perception of the location of fluorescent margins on HD images was equivalent for both filter combinations.

CONCLUSIONS

BLUE 400 AR demonstrated superior background compared with conventional BLUE 400 in malignant glioma surgery but comparable fluorescence margins and PPV. Therefore, BLUE 400 AR can be considered safe and effective in supporting malignant glioma surgery.

Development and validation of prediction scores for nosocomial infections, reoperations, and adverse events in the daily clinical setting of neurosurgical patients with cerebral and spinal tumors

OBJECTIVE

Various quality indicators are currently under investigation, aiming at measuring the quality of care in neurosurgery; however, the discipline currently lacks practical scoring systems for accurately assessing risk. The aim of this study was to develop three accurate, easy-to-use risk scoring systems for nosocomial infections, reoperations, and adverse events for patients with cerebral and spinal tumors.

METHODS

The authors developed a semiautomatic registry with administrative and clinical data and included all patients with spinal or cerebral tumors treated between September 2017 and May 2019. Patients were further divided into development and validation cohorts. Multivariable logistic regression models were used to develop risk scores by assigning points based on β coefficients, and internal validation of the scores was performed.

RESULTS

In total, 1000 patients were included. An unplanned 30-day reoperation was observed in 6.8% of patients. Nosocomial infections were documented in 7.4% of cases and any adverse event in 14.5%. The risk scores comprise variables such as emergency admission, nursing care level, ECOG performance status, and inflammatory markers on admission. Three scoring systems, NoInfECT for predicting the incidence of nosocomial infections (low risk, 1.8%; intermediate risk, 8.1%; and high risk, 26.0% [p < 0.001]), LEUCut for 30-day unplanned reoperations (low risk, 2.2%; intermediate risk, 6.8%; and high risk, 13.5% [p < 0.001]), and LINC for any adverse events (low risk, 7.6%; intermediate risk, 15.7%; and high risk, 49.5% [p < 0.001]), showed satisfactory discrimination between the different outcome groups in receiver operating characteristic curve analysis (AUC ≥ 0.7).

CONCLUSIONS

The proposed risk scores allow efficient prediction of the likelihood of adverse events, to compare quality of care between different providers, and further provide guidance to surgeons on how to allocate preoperative care.

Combination of ALA-induced fluorescence-guided resection and intraoperative open photodynamic therapy for recurrent glioblastoma: case series on a promising dual strategy for local tumor control

OBJECTIVE

High-grade glioma (HGG) prognosis remains dismal, with inevitable, mostly local recurrence. Regimens for improving local tumor control are therefore needed. Photodynamic therapy (PDT) using porfimer sodium has been investigated but was abandoned due to side effects and lack of survival benefits. Intracellular porphyrins induced by 5-aminolevulinic acid (5-ALA) are approved for fluorescence-guided resections (FGRs), but are also photosensitizers. Activated by light, they generate reactive oxygen species with resultant cytotoxicity. The authors present a combined approach of 5-ALA FGR and PDT.

METHODS

After 5-ALA FGR in recurrent HGG, laser diffusors were strategically positioned inside the resection cavity. PDT was applied for 60 minutes (635 nm, 200 mW/cm diffusor, for 1 hour) under continuous irrigation for maintaining optical clarity and ventilation with 100% oxygen. MRI was performed at 24 hours, 14 days, and every 3 months after surgery, including diffusion tensor imaging and apparent diffusion coefficient maps.

RESULTS

Twenty patients were treated. One surgical site infection after treatment was noted at 6 months as the only adverse event. MRI revealed cytotoxic edema along resection margins in 16 (80%) of 20 cases, mostly annular around the cavity, corresponding to prior laser diffusor locations (mean volume 3.3 cm3). Edema appeared selective for infiltrated tissue or nonresected enhancing tumor. At the 14-day follow-up, enhancement developed in former regions of edema, in some cases vanishing after 4-5 months. Median progression-free survival (PFS) was 6 months (95% CI 4.8-7.2 months).

CONCLUSIONS

Combined 5-ALA FGR and PDT provides an innovative and safe method of local tumor control resulting in promising PFS. Further prospective studies are warranted to evaluate long-term therapeutic effects.

Establishing risk-adjusted quality indicators in surgery using administrative data-an example from neurosurgery

BACKGROUND

The current draft of the German Hospital Structure Law requires remuneration to incorporate quality indicators. For neurosurgery, several quality indicators have been discussed, such as 30-day readmission, reoperation, or mortality rates; the rates of infections; or the length of stay. When comparing neurosurgical departments regarding these indicators, very heterogeneous patient spectrums complicate benchmarking due to the lack of risk adjustment.

OBJECTIVE

In this study, we performed an analysis of quality indicators and possible risk adjustment, based only on administrative data.

METHODS

All adult patients that were treated as inpatients for a brain or spinal tumour at our neurosurgical department between 2013 and 2017 were assessed for the abovementioned quality indicators. DRG-related data such as relative weight, PCCL (patient clinical complexity level), ICD-10 major diagnosis category, secondary diagnoses, age and sex were obtained. The age-adjusted Charlson Comorbidity Index (CCI) was calculated. Logistic regression analyses were performed in order to correlate quality indicators with administrative data.

RESULTS

Overall, 2623 cases were enrolled into the study. Most patients were treated for glioma (n = 1055, 40.2%). The CCI did not correlate with the quality indicators, whereas PCCL showed a positive correlation with 30-day readmission and reoperation, SSI and nosocomial infection rates.

CONCLUSION

All previously discussed quality indicators are easily derived from administrative data. Administrative data alone might not be sufficient for adequate risk adjustment as they do not reflect the endogenous risk of the patient and are influenced by certain complications during inpatient stay. Appropriate concepts for risk adjustment should be compiled on the basis of prospectively designed registry studies.

Fluorescence-Based Measurement of Real-Time Kinetics of Protoporphyrin IX After 5-Aminolevulinic Acid Administration in Human In Situ Malignant Gliomas

BACKGROUND

Five-aminolevulinic acid (5-ALA) is well established for fluorescence-guided resections of malignant gliomas by eliciting the accumulation of fluorescent protoporphyrin IX (PpIX) in tumors. Because of the assumed time point of peak fluorescence, 5-ALA is recommended to be administered 3 h before surgery. However, the actual time dependency of tumor fluorescence has not yet been evaluated in humans and may have important implications.

OBJECTIVE

To investigate the time dependency of PpIX by measuring fluorescence intensities in tumors at various time points during surgery.

METHODS

Patients received 5-ALA (20 mg/kg b.w.) 3 to 4 h before surgery. Fluorescence intensities (FI) and estimated tumor PpIX concentrations (CPPIX) were measured in the tumors over time with a hyperspectral camera. CPPIX was assessed using hyperspectral imaging and by evaluating fluorescence phantoms with known CPPIX.

RESULTS

A total of 201 samples from 68 patients were included in this study. On average, maximum values of calculated FI and CPPIX were observed between 7 and 8 h after 5-ALA administration. FI and CPPIX both reliably distinguished central strong and marginal weak fluorescence, and grade III compared to grade IV gliomas. Interestingly, marginal (weak) fluorescence was observed to peak later than strong fluorescence (8-9 vs 7-8 h).

CONCLUSION

In human in Situ brain tumor tissue, we determined fluorescence after 5-ALA administration to be maximal later than previously thought. In consequence, 5-ALA should be administered 4 to 5 h before surgery, with timing adjusted to internal logistical circumstances and factors related to approaching the tumor.

Adverse events in brain tumor surgery: incidence, type, and impact on current quality metrics

BACKGROUND

The aim of the study was to determine pre-operative factors associated with adverse events occurring within 30 days after neurosurgical tumor treatment in a German center, adjusting for their incidence in order to prospectively compare different centers.

METHODS

Adult patients that were hospitalized due to a benign or malignant brain were retrospectively assessed for quality indicators and adverse events. Analyses were performed in order to determine risk factors for adverse events and reasons for readmission and reoperation.

RESULTS

A total of 2511 cases were enrolled. The 30 days unplanned readmission rate to the same hospital was 5.7%. The main reason for readmission was tumor progression. Every 10th patient had an unplanned reoperation. The incidence of surgical revisions due to infections was 2.3%. Taking together all monitored adverse events, male patients had a higher risk for any of these complications (OR 1.236, 95%CI 1.025-1.490, p = 0.027). Age, sex, and histological diagnosis were predictors of experiencing any complication. Adjusted by incidence, the increased risk ratios greater than 10.0% were found for male sex, age, metastatic tumor, and hemiplegia for various quality indicators.

CONCLUSIONS

We found that most predictors of outcome rates are based on preoperative underlying medical conditions and are not modifiable by the surgeon. Comparing our results to the literature, we conclude that differences in readmission and reoperation rates are strongly influenced by standards in decision making and that comparison of outcome rates between different health-care providers on an international basis is challenging. Each health-care system has to develop own metrics for risk adjustment that require regular reassessment.

A Smart Device System to Identify New Phenotypical Characteristics in Movement Disorders

Parkinson's disease and Essential Tremor are two of the most common movement disorders and are still associated with high rates of misdiagnosis. Collected data by technology-based objective measures (TOMs) has the potential to provide new promising and highly accurate movement data for a better understanding of phenotypical characteristics and diagnostic support. A technology-based system called Smart Device System (SDS) is going to be implemented for multi-modal high-resolution acceleration measurement of patients with PD or ET within a clinical setting. The 2-year prospective observational study is conducted to identify new phenotypical biomarkers and train an Artificial Intelligence System. The SDS is going to be integrated and tested within a 20-min assessment including smartphone-based questionnaires, two smartwatches at both wrists and tablet-based Archimedean spirals drawing for deeper tremor-analyses. The electronic questionnaires will cover data on medication, family history and non-motor symptoms. In this paper, we describe the steps for this novel technology-utilizing examination, the principal steps for data analyses and the targeted performances of the system. Future work considers integration with Deep Brain Stimulation, dissemination into further sites and patient's home setting as well as integration with further data sources as neuroimaging and biobanks. Study Registration ID on ClinicalTrials.gov: NCT03638479.

5-Aminolaevulinic Acid-Induced Fluorescence in Primary Central Nervous System Lymphoma

OBJECTIVE

Diagnosis of primary central nervous system lymphoma (PCNSL) is usually confirmed by brain biopsy and subsequent neuropathologic workup. 5-Aminolevulinic acid (5-ALA)-induced fluorescence has been established for diagnostic and therapeutic purposes in glioma treatment during the last few years and is discussed for use in other cranial tumors. Its role in diagnosis and treatment of PCNSL is still elusive.

METHODS

This retrospective study includes clinical, magnetic resonance imaging, pathologic and surgical data of selected 11 patients with PCNSL at two university hospitals within the last 4 years undergoing surgical treatment for resection because of imminent mass effect or suspected cerebral glioma. Patients received 5-ALA for fluorescence-guided resection preoperatively.

RESULTS

The 11 subjects age ranged from 59 to 81 years. Postsurgical pathologic workup revealed malignant B cell lymphoma with morphologic features of diffuse large B cell lymphoma. Eight of these 11 patients with PCNSL showed a clear fluorescence induced by 5-ALA. After surgical resection, patients were treated with combination chemotherapy regimens.

CONCLUSION

In patients with glioma, the use of 5-ALA is known to be associated with increased extent of resection and survival benefit. Our data and retrospective analysis of a larger patient cohort suggest that the use of 5-ALA in PCNSL should be included in a surgical approach, if this is reconsidered for select patients within a clinical study. In addition, even photodynamic therapy in combination with 5-ALA might be studied.

Erythropoietin and VEGF promote neural outgrowth from retinal explants in postnatal rats

PURPOSE

Recent studies have reported neuroprotective effects of erythropoietin (EPO) and vascular endothelial growth factor (VEGF). The purpose of the present study was to clarify their influence on neurite outgrowth and regeneration of rat retinal ganglion cells (RGCs) in vitro and to elucidate the expression of corresponding receptors in the rat retina in vivo.

METHODS

Retinal explants from postnatal rats were stimulated with VEGF alone; VEGF in combination with anti-VEGF-receptor (VEGF-R)-2 antibody or T-type Ca2+ channel blocker ethosuximide (ESX); EPO alone; or EPO in combination with anti-EPO-receptor antibody or ESX. The presence of the corresponding receptors in the rat retina was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and by immunohistochemistry.

RESULTS

EPO induced a stable improvement of neurite outgrowth of RGCs in a dose-dependent manner (5 x 10(-15) M to 5 x 10(-13) M) up to 169% (P < 0.05). Treatment of the explants with anti-EPO-R antibody (1:80 dilution) and with ESX (5 microM) totally inhibited EPO-mediated effects on RGCs. In comparison, VEGF (50 ng/mL), induced neurite outgrowth of retina explants up to 167% (P < 0.05), which again was inhibited in the presence of anti-VEGF-R2 antibody or ESX. Transcripts of EPO-R, VEGF-R1, and VEGF-R2 were detected by RT-PCR. Intense immunoreactivity for VEGF-R1, VEGF-R2, and EPO-R were found in the RGC layer of the retina.

CONCLUSIONS

The data demonstrate for the first time that EPO and VEGF have a significant and specific biological effect on neurite regrowth of axotomized RGCs. Therefore, these results imply that EPO and VEGF have not only a neuroprotective but also a neuroregenerative role in ischemic retinal conditions.