Objective To longitudinally analyze smartphone-based real-life activity data and compare it with established clinical outcome measures in patients undergoing lumbar spine surgery for sciatica, focusing on identifying divergence in recovery trajectories.
Methods Fifty patients were assessed preoperatively and at 6 weeks (6W), 3 months (3M), and 6 months (6M). Outcomes included smartphone-derived daily Step Count, objective capacity (6-minute walking test [6WT]), and subjective disability (visual analogue scale [VAS] leg/back, Core Outcome Measures Index [COMI] back, and Oswestry Disability Index [ODI]). All metrics were standardized into z-scores relative to baseline. Piecewise linear mixed-effects (LME) models compared recovery slopes across 2 segments: phase I (early: 0–6 weeks) and phase II (late: 6 weeks–6 months).
Results The cohort (mean age, 50.7 years; 24 females) included 33 patients with lumbar disc herniation and 17 with lateral recess stenosis. All measures improved significantly during phase I (all p<0.05). However, LME modeling revealed a significant interaction between time segment and measurement type in phase II. Daily Step Count was the only metric maintaining a significant, linear upward recovery slope during the late phase (β=0.31 Z/mo). Conversely, slopes for 6WT, ODI, and COMI were significantly flatter (p<0.001 vs. Step Count), indicating a statistical plateau or “ceiling effect.” Spearman correlations between Step Count and traditional metrics weakened from strong at baseline to weak at 6 months.
Conclusion Smartphone-derived real-life activity data detect continuous functional improvement up 6 months postoperatively, whereas conventional objective and subjective measures plateau by 6 weeks. Real-world activity monitoring provides a more sensitive assessment of long-term surgical success.
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From the Editor-in-Chief: Featured Articles in the April 2026 Issue Inbo Han Neurospine.2026; 23(2): 227. CrossRef
Real-World Effectiveness Versus Efficacy in a Study Environment: How Smartphones Help Capture Meaningful Patient Recovery Trajectories – A Commentary on “Physical Performance Continues to Improve After Surgery for Sciatica, Exceeding Recovery Periods of P Victor E. Staartjes Neurospine.2026; 23(2): 239. CrossRef
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.
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Early assessment of physical capacity and pain is associated with 1-month response following epidural steroid injection in patients with sciatica due to degenerative lumbar disorders Michal Ziga, Martin N. Stienen, Anna Maria Zeitlberger, Ulf C. Schneider, Luca Regli, Victor Staartjes, Nicolai Maldaner Brain and Spine.2026; 6: 106111. CrossRef
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Assessment of the Minimum Clinically Important Difference in the Smartphone-based 6-minute Walking Test After Surgery for Lumbar Degenerative Disc Disease Anna M. Zeitlberger, Marketa Sosnova, Michal Ziga, Luca Regli, Oliver Bozinov, Astrid Weyerbrock, Martin N. Stienen, Nicolai Maldaner Spine.2021; 46(18): E959. CrossRef
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Martin Nikolaus Stienen, Nicolai Maldaner, Marketa Sosnova, Holger Joswig, Marco Vincenzo Corniola, Luca Regli, Gerhard Hildebrandt, Karl Schaller, Oliver Pascal Gautschi
Neurospine 2020;17(1):270-280. Published online January 26, 2020
Objective The patient-reported outcome measure (PROM)-based evaluation in lumbar degenerative disc disease (DDD) is today’s gold standard but has limitations. We studied the impact of lower extremity motor deficits (LEMDs) on PROMs and a new objective outcome measure.
Methods We evaluated patients with lumbar DDD from a prospective 2-center database. LEMDs were graded according to the British Medical Research Council (BMRC; 5 [normal] –0 [no movement]). The PROM-based evaluation included pain (visual analogue scale), disability (Oswestry Disability Index [ODI] & Roland-Morris Disability Index [RMDI]), and health-related quality of life (HRQoL; Short-Form 12 physical component summary/mental component summary & EuroQol-5D index). Objective functional impairment (OFI) was determined as age- and sex-adjusted Timed-Up and Go (TUG) test value.
Results One hundred five of 375 patients (28.0%) had a LEMD. Patients with LEMD had slightly higher disability (ODI: 52.8 vs. 48.2, p = 0.025; RMDI: 12.6 vs. 11.3, p = 0.034) but similar pain and HRQoL scores. OFI T-scores were significantly higher in patients with LEMD (144.2 vs. 124.3, p = 0.006). When comparing patients with high- (BMRC 0–2) vs. low-grade LEMD (BMRC 3–4), no difference was evident for the PROM-based evaluation (all p > 0.05) but patients with high-grade LEMD had markedly higher OFI T-scores (280.9 vs. 136.0, p = 0.001). Patients with LEMD had longer TUG test times and OFI T-scores than matched controls without LEMDs.
Conclusion Our data suggest that PROMs fail to sufficiently account for LEMD-associated disability, which is common and oftentimes bothersome to patients. The objective functional evaluation with the TUG test appears to be more sensitive to LEMD-associated disability. An objective functional evaluation of patients with LEMD appears reasonable.
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