Standardizing Continuous Physical Activity Monitoring in Patients with Cervical Spondylosis.

STUDY DESIGN/SETTING: Prospective cohort study. OBJECTIVE: To use a commercial wearable device to measure real-life, continuous physical activity in patients with CS and to establish age- and sex-adjusted standardized scores. SUMMARY OF BACKGROUND DATA: Patients with cervical spondylosis (CS) often present with pain or neurologic deficits that results in functional limitations and inactivity. However, little is known regarding the influence of CS on patient's real-life physical activity. METHODS: This study included 100 English-speaking adult patients with cervical degenerative diseases undergoing elective spine surgery at Stanford University who owned iPhones. Patients undergoing surgery for spine infections, trauma, or tumors, or with lumbar degenerative disease were excluded. Activity two weeks before surgery was expressed as raw daily step counts. Standardized z-scores were calculated based on age- and sex-specific values of a control population. Responses to patient-reported outcome measures (PROMs) surveys assessed convergent validity. Functional impairment was categorized based on predetermined z-score cut-off values. RESULTS: 30 CS with mean(±SD) age of 56.0(±13.4) years wore an Apple Watch for ≥8 hours/day in 87.1% of the days. Mean watch wear time was 15.7(±4.2) hours/day, and mean daily step count was 6,400(±3,792). There was no significant difference in activity between 13 patients (43%) with myelopathy and 17 (57%) without myelopathy. Test-Retest reliability between wearable step count measurements was excellent (ICC ß=0.95). Physical activity showed a moderate positive correlation with SF36-PCS, EQ5D VAS, and PROMIS-PF. Activity performance was classified into categories of "no impairment" (step count=9,640(±2,412)), "mild impairment" (6,054(±816)), "moderate impairment" (3,481(±752)), and "severe impairment" (1,619(±240)). CONCLUSION: CS patients' physical activity is significantly lower than the general population, or the frequently stated goals of 7,000-10,000 steps/day. Standardized, continuous wearable physical activity monitoring in CS is a reliable, valid, and normalized outcome tool that may help characterize functional impairment before and after spinal interventions.

Standardizing Physical Activity Monitoring in Patients With Degenerative Lumbar Disorders.

BACKGROUND AND OBJECTIVES: Degenerative thoracolumbar disorders (DTDs) typically cause pain and functional impairment. However, little is known regarding the DTD impact on patient's real-life physical activity. The objective of this study is to validate a wearable measure of physical activity monitoring in patients with DTD and to create gender- and sex-specific performance thresholds that are standardized to the mean of a control population. METHODS: A commercially available smartwatch (Apple Watch) was used to monitor preoperative physical activity in patients undergoing surgery for DTD. Mean preoperative physical activity 2 weeks before the scheduled surgery was expressed as raw step count. Standardized z-scores were referenced to age- and sex-specific values of a control population from a large public database. Step counts were assessed for convergent validity with established patient-reported outcome measures, and impairment in activity was stratified into performance groups based on z-score cutoff values. RESULTS: Sixty-five patients (62% female) with a mean (±SD) age of 63.8 (±12.8) years had a mean preoperative daily step count of 5556 (±3978). Physical activity showed significant correlation with patient-reported outcome measures, including Oswestry disability index (r = -0.26, 95% CI: -0.47-0.01), 36-Item Short Form Survey Physical Component Summary score (r = 0.30, 95% CI: 0.06-0.51), and Patient-Reported Outcomes Measurement Information System Physical Function (r = 0.49, 95% CI: 0.27-0.65). "No," "Mild," "moderate," and "severe impairment" in activity performance were defined as corresponding z-scores of >0, 0 to -0.99, -1 to -1.99, and ≤-2, accounting for 22%, 34%, 40%, and 5% of the study population. Each one-step category increase in activity impairment resulted in increased subjective disability as measured by the Oswestry Disability Index, 36-Item Short Form Survey Physical Component Summary, and Patient-Reported Outcomes Measurement Information System Physical Function (all P -values <.05). CONCLUSION: We establish the first wearable objective measure of real-life physical activity for patients with DTD, with the first age- and sex-adjusted standard scores to enable clinicians and researchers to set treatment goals and directly compare activity levels between individual patients with DTD and normal controls.

Accuracy of predicted postoperative segmental lumbar lordosis in spinal fusion using an intraoperative robotic planning and guidance system.

BACKGROUND: Restoring lumbar lordosis is one of the main goals in lumbar spinal fusion surgery. The Mazor X-AlignTM software allows for the prediction of postoperative segmental lumbar lordosis based on preoperative imaging. There is limited data on the accuracy of this preoperative prediction, especially in patients undergoing short segment lumbar fusion. The objective of our study was to determine the accuracy of predicted postoperative segmental lumbar lordosis using the Mazor X-AlignTM software in patients requiring short segmental fusion. METHODS: Retrospective analysis of adult patients undergoing pedicle screw spinal instrumentation of not more than four levels using the Mazor XTM Robot (Medtronic Inc., Minneapolis, MN, USA) between July 2017 to June 2020. The robotic guidance software, Mazor X-AlignTM (Medtronic Inc., Minneapolis, MN, USA) was used to calculate the predicted segmental lumbar lordosis based on preoperative CT-imaging and the plan was executed under intraoperative robotic guidance. Predicted segmental lumbar lordosis was compared to achieved segmental lumbar lordosis on 1-month postoperative x-rays using the Cobb angle methodology. RESULTS: A total of 15 patients (46.6% female) with a mean age of 61.5±10.9 years were included. All patients underwent posterior lumbo-sacral spinal fusion with the Mazor XTM robotic system with 11 patients (73.3%) undergoing anterior column reconstruction prior to posterior fixation. Instrumentation was performed across a mean of 2.6 levels per case. Preoperative, the mean segmental lumbar lordosis was 30.2±13.6 degrees. The mean planned segmental lumbar lordosis was 35.5±17.0 degrees while the mean achieved segmental lumbar lordosis was 35.8±16.7 degrees. There was no significant mean difference between the planned and achieved segmental lumbar lordosis (P=0.334). CONCLUSIONS: The Mazor XTM intraoperative robotic planning and guidance is accurate in predicting postoperative segmental lumbar lordosis after short segmental fusion. Our findings may assure surgical decision making and planning.

Objective outcome measures may demonstrate continued change in functional recovery in patients with ceiling effects of subjective patient-reported outcome measures after surgery for lumbar degenerative disorders.

BACKGROUND CONTEXT: The 6-minute walking test (6WT) has been previously shown to be a reliable and valid outcome measure. It is unclear if the 6WT may further help to detect differences in well performing patients that reach a ceiling effect in PROMs after surgery. PURPOSE: To evaluate changes and timing of change in objective functional impairment (OFI) as measured with the smartphone-based 6WT in relation to patient-reported outcome measures (PROMs) after surgery for degenerative lumbar disorders (DLD). STUDY DESIGN: Prospective observational cohort study. PATIENT SAMPLE: Fifty consecutive patients undergoing surgery for DLD. OUTCOME MEASURES: Patients self-determined their OFI using the 6WT application (6WT-app) and completed a set of paper-based PROMs before, 6 weeks and 3 months after surgery. METHODS: Fifty patients undergoing surgery for DLD were assessed preoperatively (baseline), 6 weeks (6W) and 3 months (3M) postoperatively. Paired sample t-tests were used to establish significant changes in raw 6-minute walking distance (6WD) and standardized Z-scores, as well as PROMs. Pearson correlation coefficient was used to define the relationship between 6WT and PROMs. Floor and ceiling effects were assessed for each PROM (visual analogue scale [VAS], core outcome measure index [COMI], Zurich claudication questionnaire [ZCQ]). RESULTS: Mean 6WT results improved from 377 m (standard deviation - SD 137; Z-score: 1.8, SD 1.8) to 490 m (SD 126; -0.7, SD 1.5) and 518 m (SD 112; -0.4, SD 1.41; all p<.05) at 6W and 3M follow-up. No significant improvement was observed between 6W and 3M for the ZCQ, VAS back and leg pain. While correlation between 6WT and all PROMs were weak at baseline, correlation coefficient increased to moderate at 3M. A considerable ceiling effect (best possible score) was observed, most notably for the ZCQ physical performance, VAS back and leg pain in 24%, 20%, and 16% of patient at 6W and in 30%, 24%, and 28% at 3M. CONCLUSIONS: Objective functional tests can describe the continued change in the physical recovery of a patient and may help to detect differences in well performing groups as well as in cases where patients' PROM results cannot further improve because of a ceiling effect.

Smartphone-based real-life activity data for physical performance outcome in comparison to conventional subjective and objective outcome measures after degenerative lumbar spine surgery.

Introduction: Outcome assessments after surgery for degenerative lumbar disorders (DLDs) rely on subjective patient-reported outcomes (PROMs). New objective functional capacity tests, like the smartphone-based 6-min walking test (6WT), have been introduced but presumably also do not reflect the patient's real-life functional performance. Research question: Pilot study to analyze changes in smartphone-based real-life activity data for physical performance outcome in patients undergoing surgery for DLD. Material and methods: Prospective observational study of DLD patients. Objective functional capacity and subjective outcomes were measured using 6WT and PROMs. Real-life physical performance data were acquired retrospectively using Apple iPhone Health data and compared against objective capacity and subjective outcomes. Results: Eight patients (mean 46 years, 62% male) provided 286.858 smartphone mile counts. PROMs and physical capacity (6WT) significantly improved postoperatively. 6WT results increased from 352m pre-to 555/567m at 6/12 weeks postoperatively (p â€‹= â€‹0.03). For physical performance a linear mixed effect models showed an increase in daily distance in the first 4 months after surgery (slope +0.178; p â€‹< â€‹0.001). However, those increases reversed from 4 until 12 months postoperatively (negative slope estimate of -0.076; p â€‹< â€‹0.001). Smartphone-derived physical performance measures showed a positive correlation with corresponding physical capacity in the 6WT (R â€‹= â€‹0.57,p â€‹= â€‹0.004) and negative correlations with PROMs (COMI: R â€‹= â€‹-0.62p â€‹= â€‹0.001; ZCQ-Physical-Function: R â€‹= â€‹-0.68,p â€‹< â€‹0.001; ZCQ-Symptom-Severity: R â€‹= â€‹-0.52,p â€‹= â€‹0.009). Discussion and conclusion: Smartphone-based real-life activity data allows for longitudinal physical performance assessment. Physical performance correlated with physical capacity and patient's subjective perception of disability. However, physical performance may be more resistant to postoperative longtime change which should consult a more cautious use as objective outcome measure.

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.

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 (ß = 0.86, 95% CI 0.81-0.90 and ß = 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.

External Validation of the Minimum Clinically Important Difference in the Timed-up-and-go Test After Surgery for Lumbar Degenerative Disc Disease.

STUDY DESIGN: Prospective observational cohort study. OBJECTIVE: The aim of this study was to provide external validation of the minimum clinically important difference (MCID) of the Timed-up-and-go (TUG) test. SUMMARY OF BACKGROUND DATA: The TUG test is one of the best explored and most frequently applied objective task-based functional outcome measure in patients with lumbar degenerative disc disease (DDD). The increased use of the TUG test is based on its solid psychometric properties; however, an external validation of the originally determined MCID is lacking. METHODS: Forty-nine patients with lumbar DDD, scheduled for elective spine surgery, were assessed pre- and 6-weeks (W6) postoperative. MCID values were calculate for raw TUG test times (seconds) and standardized TUG z scores using three different computation methods and the following established patient-reported outcome measures (PROMs) as anchors: Visual Analog Scales (VAS), Core Outcome Measures Index Back, Zurich Claudication Questionnaire (ZCQ). RESULTS: The three computation methods generated a range of MCID values, depending on the PROM used as anchor, from 0.9 s (z score of 0.3) based on the VAS leg pain to 3.0 seconds (z score of 2.7) based on the ZCQ physical function scale. The average MCID of the TUG test across all anchors and computation methods was 2.1 s (z score of 1.5). According to the average MCID of raw TUG test values or TUG z scores, 41% and 43% of patients classified as W6 responders to surgery, respectively. CONCLUSION: This study confirms the ordinally reported TUG MCID values in patients undergoing surgery for lumbar. A TUG test time change of 2.1 seconds (or TUG z score change of 1.5) indicates an objective and clinically meaningful change in functional status. This report facilitates the interpretation of TUG test results in clinical routine as well as in research.Level of Evidence: 3.

Assessment of the Minimum Clinically Important Difference in the Smartphone-based 6-minute Walking Test After Surgery for Lumbar Degenerative Disc Disease.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of this study was to determine the minimum clinically important difference (MCID) of the 6-minute walking test (6WT) after surgery for lumbar degenerative disc disease (DDD). SUMMARY OF BACKGROUND DATA: The smartphone-based 6WT is a valid and reliable tool to quantify objective functional impairment in patients with lumbar DDD. To date, the MCID of the 6WT has not been described in patients with DDD. METHODS: We assessed patients pre- and 6-weeks postoperatively, analyzing both raw 6-minute walking distances (6WD; in meters) and standardized 6WT z scores. Three methods were applied to compute MCID values using established patient-reported outcomes measures (PROMs) as anchors (VAS back/leg pain, Zurich Claudication Questionnaire [ZCQ], Core Outcome Measures Index [COMI]): average change, minimum detectable change, and the change difference approach. RESULT: We studied 49 patients (59% male) with a mean age of 55.5 ±â€Š15.8 years. The computation methods revealed MCID values ranging from 81 m (z score of 0.9) based on the VAS back pain to 99 m (z score of 1.0) based on the ZCQ physical function scale. The average MCID of the 6WT was 92 m (z score of 1.0). Based on the average MCID of raw 6WD values or standardized z scores, 53% or 49% of patients classified as 6-week responders to surgery for lumbar DDD, respectively. CONCLUSION: The MCID for the 6WT in lumbar DDD patients is variable, depending on the calculation technique. We propose a MCID of 92m (z score of 1.0), based on the average of all three methods. Using a z score as MCID allows for the standardization of clinically meaningful change and attenuates age- and sex-related differences.Level of Evidence: 3.

Responsiveness of the self-measured 6-minute walking test and the Timed Up and Go test in patients with degenerative lumbar disorders.

OBJECTIVE: The 6-minute walking test (6WT) and the Timed Up and Go (TUG) test are two of the most commonly applied standardized measures of objective functional impairment that help support clinical decision-making for patients undergoing surgery for degenerative lumbar disorders. This study correlates smartphone-app-based 6WT and TUG results to evaluate their responsiveness. METHODS: In a prospective study, 49 consecutive patients were assessed preoperatively and 6 weeks postoperatively using the 6WT, the TUG test, and commonly used patient-reported outcome measures. Raw values and standardized z-scores of both objective tests were correlated. An external criterion for treatment success was created based on the Zurich Claudication Questionnaire patient satisfaction subscale. Internal and external responsiveness for both functional tests was evaluated. RESULTS: The mean preoperative 6WT results improved from 401 m (SD 129 m), z-score -1.65 (SD 1.6) to 495 m (SD 129 m), z-score -0.71 (SD 1.6, p < 0.001). The mean preoperative TUG test results improved from 10.44 seconds (SD 4.37, z-score: -3.22) to 8.47 seconds (SD 3.38, z-score: -1.93, p < 0.001). The 6WT showed a strong negative correlation with TUG test results (r = -66, 95% CI 0.76-0.53, p < 0.001). The 6WT showed higher internal responsiveness (standardized responsive mean = 0.86) compared to the TUG test (standardized responsive mean = 0.67). Evaluation of external responsiveness revealed that the 6WT was capable of differentiating between patients who were satisfied and those who were unsatisfied with their treatment results (area under the curve = 0.70), whereas this was not evident for the TUG test ( area under the curve = 0.53). CONCLUSIONS: Both tests adequately quantified functional impairment in surgical candidates with degenerative lumbar disorders. The 6WT demonstrated better internal and external responsiveness compared with the TUG test. Clinical trial registration no.: NCT03977961 (clinicaltrials.gov). ABBREVIATIONS: AUC = area under the curve; COMI = Core Outcome Measures Index; DLDs = degenerative lumbar disorders; LDH = lumbar disc herniation; LSS = lumbar spinal stenosis; PROM = patient-reported outcome measure; ROC = receiver operating characteristic; SRM = standardized responsive mean; TUG = Timed Up and Go; VAS = visual analog scale; 6WD = 6-minute walking distance; 6WT = 6-minute walking test; ZCQ = Zurich Claudication Questionnaire.

Patients undergoing surgery for lumbar degenerative spinal disorders favor smartphone-based objective self-assessment over paper-based patient-reported outcome measures.

BACKGROUND CONTEXT: Smartphone-based applications enable new prospects to monitor symptoms and assess functional outcome in patients with lumbar degenerative spinal disorders. However, little is known regarding patient acceptance and preference towards new modes of digital objective outcome assessment. PURPOSE: To assess patient preference of an objective smartphone-based outcome measure compared to conventional paper-based subjective methods of outcome assessment. STUDY DESIGN: Prospective observational cohort study. PATIENT SAMPLE: Fourty-nine consecutive patients undergoing surgery for lumbar degenerative spinal disorder. OUTCOME MEASURES: Patients completed a preference survey to assess different methods of outcome assessment. A 5-level Likert scale ranged from strong disagreement (2 points) over neutral (6 points) to strong agreement (10 points) was used. METHODS: Patients self-determined their objective functional impairment using the 6-minute Walking Test application (6WT-app) and completed a set of paper-based patient-reported outcome measures (PROMs) before and 6 weeks after surgery. Patients were then asked to rate the methods of outcome assessment in terms of suitability, convenience, and responsiveness to their symptoms. RESULTS: The majority of patients considered the 6WT-app a suitable instrument (median 8.0, interquartile range [IQR] 4.0). Patients found the 6WT more convenient (median 10.0, IQR 2.0) than the Zurich Claudication Questionnaire (ZCQ; median 8.0, IQR 4.0, p=.019) and Core Outcome Measure Index (COMI; median 8.0, IQR 4.0, p=.007). There was good agreement that the 6WT-app detects change in physical performance (8.0, IQR 4.0). 78 % of patients considered the 6WT superior in detecting differences in symptoms (vs. 22% for PROMs). Seventy-six percent of patients would select the 6WT over the other, 18% the ZCQ and 6% the COMI. Eighty-two percent of patients indicated their preference to use a smartphone app for the assessment and monitoring of their spine-related symptoms in the future. CONCLUSIONS: Patients included in this study favored the smartphone-based evaluation of objective functional impairment over paper-based PROMs. Involving patients more actively by means of digital technology may increase patient compliance and satisfaction as well as diagnostic accuracy.

External Validation of the Timed Up and Go Test as Measure of Objective Functional Impairment in Patients With Lumbar Degenerative Disc Disease.

BACKGROUND: The Timed Up and Go (TUG) test is the most commonly applied objective measure of functional impairment in patients with lumbar degenerative disc disease (DDD). OBJECTIVE: To demonstrate external content validity of the TUG test. METHODS: Consecutive adult patients, scheduled for elective lumbar spine surgery, were screened for enrollment into a prospective observational study. Disease severity was estimated by patient-reported outcome measures (PROMs; Visual Analog Scales [VAS], Core Outcome Measures Index [COMI] back, Zurich Claudication Questionnaire [ZCQ]) and the TUG test. Pearson correlation coefficients (PCCs) were used to describe the relationship between logarithmic TUG test raw values and PROMs. RESULTS: A total of 70 patients (mean age 55.9 ± 15.4 yr; 38.6% female; 27.1% previous spine surgery; 28.6% lower extremity motor deficits) with lumbar disc herniation (50%), lumbar spinal stenosis (34.3%), or instability requiring spinal fusion (15.7%) were included. The mean TUG test time was 10.8 ± 4.4 s; age- and sex-adjusted objective functional impairment (OFI) T-score was 134.2 ± 36.9. A total of 12 (17.1%) patients had mild, 14 (20%) moderate, and 9 (12.9%) severe OFI, while 35 (50%) had TUG test results within the normal population range (no OFI). PCCs between TUG test time and VAS back pain were r = 0.37 (P = .002), VAS leg pain r = 0.37 (P = .002), COMI back r = 0.50 (P < .001), ZCQ symptom severity r = 0.41 (P < .001), and ZCQ physical function r = 0.36 (P = .002). CONCLUSION: This external validation demonstrated similar OFI rates and PCCs between logarithmic TUG test results and PROMs compared to the original article from 2016. These findings support the TUG test being a quick, easy-to-use objective test, which provides the physician with a robust estimate of pain and functional impairment.

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.

Assessing the surgical outcome of the "chopsticks" technique in endoscopic transsphenoidal adenoma surgery.

OBJECTIVE: The "chopsticks" technique is a 3-instrument, 2-hand mononostril technique that has been recently introduced in endoscopic neurosurgery. It allows a dynamic surgical view controlled by one surgeon only while keeping bimanual dissection. Being a mononostril approach, it requires manipulation of the mucosa of one nasal cavity only. The rationale of the technique is to reduce nasal morbidity without compromising surgical results and complication rates. There are, however, no data available on its results in endoscopic surgery (transsphenoidal surgery [TSS]) for pituitary adenoma. METHODS: The authors performed a cohort analysis of prospectively collected data on 144 patients (156 operations) undergoing TSS using the chopsticks technique with 3T intraoperative MRI. All patients had at least 3 months of postoperative neurosurgical, endocrinological, and rhinological follow-up (Sino-Nasal Outcome Test-20 [SNOT-20] and Sniffin' Sticks). The surgical technique is described, and the achieved gross-total resection (GTR) and extent of resection (EOR) together with patients' clinical outcomes and complications are descriptively reported. RESULTS: On 3-month postoperative MRI, GTR was achieved in 71.2% of patients with a mean EOR of 96.7%. GTR was the surgical goal in 122 of 156 cases and was achieved in 106 of 122 (86.9%), with a mean EOR of 98.7% (median 100%, range 49%-100%). There was no surgical mortality. At a median follow-up of 15 months (range 3-70 months), there was 1 permanent neurological deficit. As of the last available follow-up, 11.5% of patients had a new pituitary single-axis deficit, whereas 26.3% had improvement in endocrinological function. Three patients had new postoperative hyposmia. One patient had severe impairment of sinonasal function (SNOT-20 score > 40). The operation resulted in endocrine remission in 81.1% of patients with secreting adenomas. CONCLUSIONS: This study shows that the chopsticks technique confers resection and morbidity results that compare favorably with literature reports of TSS. This technique permits a single surgeon to perform effective endoscopic bimanual dissection through a single nostril, reducing manipulation of healthy tissue and thereby possibly minimizing surgical morbidity.

Longitudinal smartphone-based self-assessment of objective functional impairment in patients undergoing surgery for lumbar degenerative disc disease: initial experience.

BACKGROUND: The worldwide spread of smartphone usage enables new possibilities for longitudinal monitoring of objective functional impairment (OFI) in patients undergoing surgery for lumbar degenerative disc disease (DDD). METHODS: Three patients, undergoing elective surgery for lumbar DDD, self-assessed OFI using a recently validated 6-min walking test (6WT) smartphone application. Results are presented as raw 6-min walking distance (6WD) as well as in reference to age- and sex-specific healthy population reference values using standardized z-scores (number of standard deviations). In parallel, patient-reported outcome measures (PROMs), including numeric rating scale (NRS) leg-pain and Core Outcome Measures Index (COMI) were obtained before (pre) and 6 weeks (6 W) as well as 3 months (3 M) after surgery. Descriptive analyses were used to compare PROMs with repeated 6WT measurements over time. The feasibility and benefits of the longitudinal OFI measurements using the 6WT app are discussed. RESULTS: One patient presented a favorable outcome, reflected by a clinically meaningful improvement in PROMs. Correspondingly, the 6WT distance gradually improved above the normal population values ((pre 399 m (z-score - 1.96) vs. 6 W 494 m (- 0.85) vs. 3 M 557 m (- 0.1)). One patient experienced initial improvement at 6 W, followed by a decline in 6WD at 3 M which promoted further interventions with subsequent recovery ((358 m (z-score - 3.29) vs 440 m (- 2.2) vs 431 m (- 2.32) vs 471 m (- 1.78)). The last patient showed a lack of improvement in PROMs as well as in OFI (360 m (z-score 0.0) vs 401 m (0.30) vs 345 m (- 0.11)) resulting in secondary surgery. CONCLUSION: The longitudinal assessment of OFI using the 6WT app was feasible and provided the physician with a detailed history of patients' postoperative walking capacity complementing commonly used PROMs.

Normative data of a smartphone app-based 6-minute walking test, test-retest reliability, and content validity with patient-reported outcome measures.

OBJECTIVE: The 6-minute walking test (6WT) is used to determine restrictions in a subject's 6-minute walking distance (6WD) due to lumbar degenerative disc disease. To facilitate simple and convenient patient self-measurement, a free and reliable smartphone app using Global Positioning System coordinates was previously designed. The authors aimed to determine normative values for app-based 6WD measurements. METHODS: The maximum 6WD was determined three times using app-based measurement in a sample of 330 volunteers without previous spine surgery or current spine-related disability, recruited at 8 centers in 5 countries (mean subject age 44.2 years, range 16-91 years; 48.5% male; mean BMI 24.6 kg/m2, range 16.3-40.2 kg/m2; 67.9% working; 14.2% smokers). Subjects provided basic demographic information, including comorbidities and patient-reported outcome measures (PROMs): visual analog scale (VAS) for both low-back and lower-extremity pain, Core Outcome Measures Index (COMI), Zurich Claudication Questionnaire (ZCQ), and subjective walking distance and duration. The authors determined the test-retest reliability across three measurements (intraclass correlation coefficient [ICC], standard error of measurement [SEM], and mean 6WD [95% CI]) stratified for age and sex, and content validity (linear regression coefficients) between 6WD and PROMs. RESULTS: The ICC for repeated app-based 6WD measurements was 0.89 (95% CI 0.87-0.91, p < 0.001) and the SEM was 34 meters. The overall mean 6WD was 585.9 meters (95% CI 574.7-597.0 meters), with significant differences across age categories (p < 0.001). The 6WD was on average about 32 meters less in females (570.5 vs 602.2 meters, p = 0.005). There were linear correlations between average 6WD and VAS back pain, VAS leg pain, COMI Back and COMI subscores of pain intensity and disability, ZCQ symptom severity, ZCQ physical function, and ZCQ pain and neuroischemic symptoms subscores, as well as with subjective walking distance and duration, indicating that subjects with higher pain, higher disability, and lower subjective walking capacity had significantly lower 6WD (all p < 0.001). CONCLUSIONS: This study provides normative data for app-based 6WD measurements in a multicenter sample from 8 institutions and 5 countries. These values can now be used as reference to compare 6WT results and quantify objective functional impairment in patients with degenerative diseases of the spine using z-scores. The authors found a good to excellent test-retest reliability of the 6WT app, a low area of uncertainty, and high content validity of the average 6WD with commonly used PROMs.

The Zurich Pituitary Score predicts utility of intraoperative high-field magnetic resonance imaging in transsphenoidal pituitary adenoma surgery.

BACKGROUND: It is currently unclear if there are subsets of patients undergoing transsphenoidal surgery (TSS) in which intraoperative high-field magnetic resonance imaging (3T-iMRI) is particularly advantageous. We aimed to investigate whether a radiological grading scale predicts the utility of 3T-iMRI in pituitary adenoma (PA) TSS. METHODS: From a prospective registry, patients who underwent endoscopic TSS for PA using 3T-iMRI were identified. Adenomas were graded using the Zurich Pituitary Score (ZPS). We assessed improvement after 3T-iMRI in terms of gross total resection (GTR), residual volume (RV), and extent of resection (EOR). RESULTS: Among 95 patients, rates of conversion to GTR after 3T-iMRI decreased steadily from 33% for grade I to 0% for grade IV adenomas, with a statistically significant conversion rate only for grade I (p = 0.008) and grade II (p < 0.001). All grade I adenomas were completely resected after 3T-iMRI. Median RV change was statistically significant for grades I to III, but not for grade IV (p = 0.625). EOR improvement ranged from a median change of 0.0% (IQR 0.0-4.5%) for grade I to 4.4% (IQR 0.0-9.0%) for grade IV, with a significant improvement only for grades I to III (p < 0.05). CONCLUSIONS: Interestingly, this study shows that clinical utility of 3T-iMRI is highest in the more "simple" adenomas (ZPS grades I-II) than for the more "complex" ones (ZPS grade III-IV). Grade I adenomas are amenable to GTR if 3T-iMRI is implemented. In grade III adenomas, EOR and RV can be improved to clinically relevant levels. Conversely, in grade IV adenomas, 3T-iMRI may be of limited use.

Influence of the Intensive Care Unit Environment on the Reliability of the Montreal Cognitive Assessment.

Background: Neuropsychological screening becomes increasingly important for the evaluation of subarachnoid hemorrhage (SAH) and stroke patients. It is often performed during the surveillance period on the intensive (ICU), while it remains unknown, whether the distraction in this environment influences the results. We aimed to study the reliability of the Montreal Cognitive Assessment (MoCA) in the ICU environment. Methods: Consecutive stable patients with recent brain injury (tumor, trauma, stroke, etc.) were evaluated twice within 36 h using official parallel versions of the MoCA (ΔMoCA). The sequence of assessment was randomized into (a) busy ICU first or (b) quiet office first with subsequent crossover. For repeated MoCA, we determined sequence, period, location effects, and the intraclass correlation coefficient (ICC). Results: N = 50 patients were studied [n = 30 (60%) male], with a mean age of 57 years. The assessment's sequence ["ICU first" mean ΔMoCA -1.14 (SD 2.34) vs. "Office first" -0.73 (SD 1.52)] did not influence the MoCA (p = 0.47). On the 2nd period, participants scored 0.96 points worse (SD 2.01; p = 0.001), indicating no MoCA learning effect but a possible difference in parallel versions. There was no location effect (p = 0.31) with ΔMoCA between locations (Office minus ICU) of -0.32 (SD 2.21). The ICC for repeated MoCA was 0.87 (95% CI 0.79-0.92). Conclusions: The reliability of the MoCA was excellent, independent from the testing environment being ICU or office. This finding is helpful for patient care and studies investigating the effect of a therapeutic intervention on the neuropsychological outcome after SAH, stroke or traumatic brain injury.

Neural network-based identification of patients at high risk for intraoperative cerebrospinal fluid leaks in endoscopic pituitary surgery.

OBJECTIVE: Although rates of postoperative morbidity and mortality have become relatively low in patients undergoing transnasal transsphenoidal surgery (TSS) for pituitary adenoma, cerebrospinal fluid (CSF) fistulas remain a major driver of postoperative morbidity. Persistent CSF fistulas harbor the potential for headache and meningitis. The aim of this study was to investigate whether neural network-based models can reliably identify patients at high risk for intraoperative CSF leakage. METHODS: From a prospective registry, patients who underwent endoscopic TSS for pituitary adenoma were identified. Risk factors for intraoperative CSF leaks were identified using conventional statistical methods. Subsequently, the authors built a prediction model for intraoperative CSF leaks based on deep learning. RESULTS: Intraoperative CSF leaks occurred in 45 (29%) of 154 patients. No risk factors for CSF leaks were identified using conventional statistical methods. The deep neural network-based prediction model classified 88% of patients in the test set correctly, with an area under the curve of 0.84. Sensitivity (83%) and specificity (89%) were high. The positive predictive value was 71%, negative predictive value was 94%, and F1 score was 0.77. High suprasellar Hardy grade, prior surgery, and older age contributed most to the predictions. CONCLUSIONS: The authors trained and internally validated a robust deep neural network-based prediction model that identifies patients at high risk for intraoperative CSF. Machine learning algorithms may predict outcomes and adverse events that were previously nearly unpredictable, thus enabling safer and improved patient care and better patient counseling.

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

INTRODUCTION: 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. METHODS: Retrospective analysis of prospectively collected data in our institutional patient registry on consecutive patients undergoing surgery for cSDH from 2013 to 2017. Complications were assessed according to the Clavien-Dindo grading system (CDG). The outcome was measured with respect to two endpoints: occurrence of a complication with CDG 3-5 and lack of improvement in Karnofsky Performance Status (KPS) at the last follow-up. RESULTS: Out of 435 operations, 166 (38.3%) presented a complication until 3 months postoperative (CDG 1, 23 (5.3%); CDG 2, 62 (14.3%); CDG 3a, 7 (1.6%); CDG 3b, 64 (14.7%); CDG 4a, 2 (0.5%); and CDG 5, 8 (1.8%)). Higher CDG correlated with a lower KPS (rs = - 0.27, p < 0.001). A lack of improvement in KPS was associated with a Charlson Comorbidity Index (CCI) > 1 and the iso- or hypodense appearance of the cSDH. CONCLUSIONS: This study provides a reliable estimate of the rate of medical and surgical complications in cSDH surgery. Complications that required a surgical intervention turned out to be rare. Recording complications in a standardized and prospective fashion can therefore serve as a basis for assessing patient outcome and quality control within the department.