Distance to first symptoms measured by the 6-min walking test differentiates between treatment success and failure in patients with degenerative lumbar disorders

PURPOSE The smartphone-based 6-min walking test (6WT) is an established digital outcome measure in patients undergoing surgery for degenerative lumbar disorders (DLD). In addition to the 6WTs primary outcome measure, the 6-min walking distance (6WD), the patient's distance to first symptoms (DTFS) and time to first symptoms (TTFS) can be recorded. This is the first study to analyse the psychometric properties of the DTFS and TTFS. METHODS Forty-nine consecutive patients (55 ± 15.8 years) completed the 6WT pre- and 6 weeks (W6) postoperative. DTFS and TTFS were assessed for reliability and content validity using disease-specific patient-reported outcome measures. The Zurich Claudication Questionnaire patient satisfaction subscale was used as external criterion for treatment success. Internal and external responsiveness for both measures at W6 was evaluated. RESULTS There was a significant improvement in DTFS and TTFS from baseline to W6 (p < 0.001). Both measures demonstrated a good test-retest reliability (β = 0.86, 95% CI 0.81-0.90 and β = 0.83, 95% CI 0.76-0.87, both p < 0.001). The DTFS exceeded the 6WD capability to differentiate between satisfied (82%) and unsatisfied patients (18%) with an AUC of 0.75 (95% CI 0.53-0.98) vs. 0.70 (95% CI 0.52-0.90). The TTFS did not demonstrate meaningful discriminative abilities. CONCLUSION Change in DTFS can differentiate between satisfied and unsatisfied patients after spine surgery. Digital outcome measures on the 6WT metric provide spine surgeons and researchers with a mean to assess their patient's functional disability and response to surgical treatment in DLD

FUSE-ML: development and external validation of a clinical prediction model for mid-term outcomes after lumbar spinal fusion for degenerative disease

Background: Indications and outcomes in lumbar spinal fusion for degenerative disease are notoriously heterogenous. Selected subsets of patients show remarkable benefit. However, their objective identification is often difficult. Decision-making may be improved with reliable prediction of long-term outcomes for each individual patient, improving patient selection and avoiding ineffective procedures. Methods: Clinical prediction models for long-term functional impairment [Oswestry Disability Index (ODI) or Core Outcome Measures Index (COMI)], back pain, and leg pain after lumbar fusion for degenerative disease were developed. Achievement of the minimum clinically important difference at 12 months postoperatively was defined as a reduction from baseline of at least 15 points for ODI, 2.2 points for COMI, or 2 points for pain severity. Results: Models were developed and integrated into a web-app ( https://neurosurgery.shinyapps.io/fuseml/ ) based on a multinational cohort [N = 817; 42.7% male; mean (SD) age: 61.19 (12.36) years]. At external validation [N = 298; 35.6% male; mean (SD) age: 59.73 (12.64) years], areas under the curves for functional impairment [0.67, 95% confidence interval (CI): 0.59-0.74], back pain (0.72, 95%CI: 0.64-0.79), and leg pain (0.64, 95%CI: 0.54-0.73) demonstrated moderate ability to identify patients who are likely to benefit from surgery. Models demonstrated fair calibration of the predicted probabilities. Conclusions: Outcomes after lumbar spinal fusion for degenerative disease remain difficult to predict. Although assistive clinical prediction models can help in quantifying potential benefits of surgery and the externally validated FUSE-ML tool may aid in individualized risk-benefit estimation, truly impacting clinical practice in the era of "personalized medicine" necessitates more robust tools in this patient population. Keywords: Clinical prediction model; Machine learning; Neurosurgery; Outcome prediction; Predictive analytics; Spinal fusion

Diagnostic reliability of the Berlin classification for complex MCA aneurysms—usability in a series of only giant aneurysms

Background and objective The main challenge of bypass surgery of complex MCA aneurysms is not the selection of the bypass type but the initial decision-making of how to exclude the affected vessel segment from circulation. To this end, we have previously proposed a classification for complex MCA aneurysms based on the preoperative angiography. The current study aimed to validate this new classification and assess its diagnostic reliability using the giant aneurysm registry as an independent data set. Methods We reviewed the pretreatment neuroimaging of 51 patients with giant (> 2.5 cm) MCA aneurysms from 18 centers, prospectively entered into the international giant aneurysm registry. We classified the aneurysms according to our previously proposed Berlin classification for complex MCA aneurysms. To test for interrater diagnostic reliability, the data set was reviewed by four independent observers. Results We were able to classify all 51 aneurysms according to the Berlin classification for complex MCA aneurysms. Eight percent of the aneurysm were classified as type 1a, 14% as type 1b, 14% as type 2a, 24% as type 2b, 33% as type 2c, and 8% as type 3. The interrater reliability was moderate with Fleiss's Kappa of 0.419. Conclusion The recently published Berlin classification for complex MCA aneurysms showed diagnostic reliability, independent of the observer when applied to the MCA aneurysms of the international giant aneurysm registry.Peer reviewe

Digital Objective Measures of Functional Impairment for Lumbar Degenerative Disc Disease

It is increasingly acknowledged that objective measures of functional impairment may complement subjective patient-reported outcome measures (PROMs) for the comprehensive assessment of patient undergoing surgery for lumbar degenerative disc disease (DDD). These objective functional tests, however, previously required trained personnel and special equipment, they lacked standardization and were generally associated with a high responder burden. The following collection of articles present our scientific work to overcome these challenges, to validate and standardize objective outcome assessment in lumbar DDD patients with the help of digital devices. In part 1 we present the first published systematic review of the literature summarizing the state of current research and identify research needs and opportunities. We then provide external validation of the psychometric properties of the currently most frequently used measure, the Timed-up-and-Go (TUG) test, using a specifically developed smartphone app. We compare TUG results against commonly used PROMs and establish a standardized age- and sex adjusted minimum clinically important difference (MCID) value. In the second part we summarize the systematic development of a new app-based objective outcome measure, the 6-minute Walking Test (6WT). In developing the 6WT we exploit the full potential of a digital instrument, eliminating shortcomings of existing tests. We report on our first experience longitudinally monitoring lumbar DDD patients. We then provide content validity against a set of PROMs and demonstrate that the 6WT is a convenient, reliable, and valid way to quantify objective functional impairment. Using spine-healthy population reference data we calculate age- and sex dependent standardized z-scores to create a convenient severity stratification that allows for interindividual comparison. We show that change in 6WT results may differentiate between patients who are satisfied and unsatisfied with surgery. Finally, we demonstrate that patient preference and acceptance of smartphone-based outcome assessment compare favorably with questionnaire-based PROMs

Neue Entwicklungen in der Diagnostik von Intrakraniellen Riesenaneurysmen

Background: Giant intracranial aneurysms (GIA) differ substantially from smaller IA not only concerning their management but also concerning their diagnostics. The main objective of the studies summarized below is to develop and compare new diagnostic and monitoring techniques in GIA using magnet resonance imaging (MRI). In particular, we describe different modes of GIA quantification and the occurrence of perianeurysmal edema (PAE) and partial thrombosis (PT). In addition, we aim to delineate changes in GIA volume and mass effect on the brain after surgical GIA treatment that is not directed at immediate aneurysm occlusion. Methods: MRIs of 69 GIA were retrospectively analyzed regarding GIA location, diameter and volume as well as the occurrence and volume of PAE and PT. Furthermore, the clinical impact of these parameters was evaluated. In a second step, we measured changes in GIA volume, lateral ventricle volume (LVV) and mid-line shift (MLS) by using pre- and postoperative MRIs of 19 anterior circulation GIA. Results: Comparing GIA sizes produced different results depending on whether GIA diameter or volume was measured. A correlation between these two modes of measurement was only observed in anterior circulation GIA. Only GIA location but not GIA size correlated with the patient's clinical condition. PAE was observed only in one third of all cases. Both GIA volume and PT were associated with the occurrence and size of PAE. Our cohort of 19 anterior circulation GIA showed a significant decrease in postoperative GIA volume as well as an increase in LVV and a reduction in MLS. The decrease in GIA volume correlated with the increase in ipsilateral LVV but not with the change in MLS. Conclusion: Our data suggest that GIA size is clinically less relevant than examining GIA location, shape and mass effect. However, GIA volume as well as PT have a distinct influence on the occurrence of PAE. Since cavernous ICA aneurysms showed no PAE at all one may speculate that the dura mater could serve as a barrier protecting the brain from PAE formation. We showed that indirect surgical GIA therapy leads to a significant decrease in postoperative GIA volume and mass effect exerted on the brain.Hintergrund: Intrakranielle Riesenaneurysmen (GIA) unterscheiden sich klinisch und morphologisch deutlich von kleineren Aneurysmen und stellen daher in ihrer Diagnostik und Therapie eine besondere Herausforderung dar. Hauptziel der Arbeit ist es, neue Ansätze in der bildgebenden Diagnostik darzustellen und diese zu untersuchen. Im Besonderen beschreibt die Arbeit verschiedene Methoden zur Quantifizierung von GIA sowie das Auftreten von perianeurymalem Ödem (PAE) und partieller Thrombosierung (PT). Zusätzlich wurden die Änderung des GIA-Volumens und des von ihm ausgehenden Masseneffekts nach operativer Therapie analysiert. Methoden: Präoperative MRTs von 69 GIA wurden retrospektiv untersucht in Bezug auf die Lokalisation, den maximalen GIA- Durchmesser, das Volumen sowie das Auftreten und Volumen von PAE und PT. Zusätzlich wurde der klinische Einfluss der GIA-Größe analysiert. In einem zweiten Schritt wurde in prä- sowie postoperativen MRTs von 19 anterioren GIA das GIA-Volumen, das Seitenventrikelvolumen (LVV) sowie die Mittellinienverlagerung (MLS) bestimmt. Ergebnisse: Die Messungen des GIA- Durchmessers und die GIA-Volumetrie erzeugten voneinander unterschiedliche Ergebnisse. Eine Korrelation beider Messtechniken zeigte sich nur bei anterioren GIA. Nicht die GIA-Größe, sondern nur die GIA-Lokalisation korrelierte mit dem neurologischen Zustand des Patienten. PAE zeigte sich in einem Drittel aller GIA. Das GIA-Volumen, ebenso wie PT, waren assoziiert mit dem Auftreten und der Größe von PAE. In den 19 anterioren GIA zeigte sich postoperativ im MRT eine signifikante Reduktion des GIA-Volumens sowie eine Vergrößerung des LVV und ein Rückgang des MLS. Die postoperative GIA- Volumenreduktion korrelierte mit der Veränderung des LVV und nicht mit dem MLS. Schlussfolgerung: Unsere Daten deuten darauf hin, dass GIA-Lokalisation, Form und Masseneffekt wichtiger für den präoperativen klinischen Zustand sind als GIA-Größe. Jedoch hat das GIA-Volumen, genauso wie PT, einen ausschlaggebenden Einfluss auf das Auftreten von PAE. Indirekte operative GIA- Therapie führt zu einer Reduktion sowohl des GIA-Volumens als auch des Masseneffekts auf das angrenzende Hirngeweb

Diagnostic reliability of the Berlin classification for complex MCA aneurysms-usability in a series of only giant aneurysms

BACKGROUND AND OBJECTIVE The main challenge of bypass surgery of complex MCA aneurysms is not the selection of the bypass type but the initial decision-making of how to exclude the affected vessel segment from circulation. To this end, we have previously proposed a classification for complex MCA aneurysms based on the preoperative angiography. The current study aimed to validate this new classification and assess its diagnostic reliability using the giant aneurysm registry as an independent data set. METHODS We reviewed the pretreatment neuroimaging of 51 patients with giant (> 2.5 cm) MCA aneurysms from 18 centers, prospectively entered into the international giant aneurysm registry. We classified the aneurysms according to our previously proposed Berlin classification for complex MCA aneurysms. To test for interrater diagnostic reliability, the data set was reviewed by four independent observers. RESULTS We were able to classify all 51 aneurysms according to the Berlin classification for complex MCA aneurysms. Eight percent of the aneurysm were classified as type 1a, 14% as type 1b, 14% as type 2a, 24% as type 2b, 33% as type 2c, and 8% as type 3. The interrater reliability was moderate with Fleiss's Kappa of 0.419. CONCLUSION The recently published Berlin classification for complex MCA aneurysms showed diagnostic reliability, independent of the observer when applied to the MCA aneurysms of the international giant aneurysm registry

Standardized assessment of outcome and complications in chronic subdural hematoma: results from a large case series

Chronic subdural hematomas (cSDH) are commonly deemed to have a benign prognosis. However, detailed and standardized data describing outcome and complications in a large prospective patient cohort is lacking

Smartphone-Based Self-Assessment of Objective Functional Impairment (6-Minute Walking Test) in Patients Undergoing Epidural Steroid Injection

Epidural steroid injection (ESI) represents a popular treatment option in patients with lumbar degenerative disc disease (DDD). The main objective of the article was to determine whether the 6-minute walking test (6WT) could assist in the discrimination between ESI responders and nonresponders. We used a validated 6WT smartphone application to assess self-measured objective functional impairment (OFI) in 3 patients with DDD undergoing ESI. Patient-reported outcome measures (PROMs), including the Core Outcome Measures Index and the Oswestry Disability Index, were obtained at baseline and at the 3-, 7-, and 28-day follow-up. Descriptive analyses were used to compare PROMs with OFI over time. Two patients responded well to the ESI, illustrated by clinically meaningful improvements in PROMs. This improvement was accompanied by a substantial increase in the 6WT distance (case I: 358 m vs. 517 m and case II: 296 m vs. 625 m). One patient reported only moderate improvement in leg pain and conflicting results in the other PROMs. The 6WT demonstrated a persistent OFI (487 m vs. 488 m). This patient was considered a nonresponder and underwent surgical treatment. This case series illustrates the feasibility of the smartphone-based 6WT as a tool to assess OFI in patients undergoing ESI for lumbar DDD