Lower Extremity Motor Deficits Are Underappreciated in Patient-Reported Outcome Measures: Added Value of Objective Outcome Measures

Neurospine Neurospine 2020;17(1):270-280. https://doi.org/10.14245/ns.1938368.184 Original Article Corresponding Author Martin Nikolaus Stienen https://orcid.org/0000-0002-6417-1787 Department of Neurosurgery, University Hospital Zurich, Clinical Neuroscience Center, University of Zurich, Frauenklinikstrasse 10, 8091 Zurich, Switzerland E-mail: pISSN 2586-6583 eISSN 2586-6591 Lower Extremity Motor Deficits Are Underappreciated in Patient-Reported Outcome Measures: Added Value of Objective Outcome Measures Martin Nikolaus Stienen1,2, Nicolai Maldaner3, Marketa Sosnova3, Holger Joswig4, Marco Vincenzo Corniola5, Luca Regli1,2, Gerhard Hildebrandt3, Karl Schaller5, Oliver Pascal Gautschi6 Department of Neurosurgery, University Hospital Zurich, Zurich, Switzerland Clinical Neuroscience Center, University of Zurich, Zurich, Switzerland 3 Department of Neurosurgery, Kantonsspital St. Gallen, St. Gallen, Switzerland 4 Department of Neurosurgery, Ernst von Bergmann Hospital, Potsdam, Germany 5 Division of Neurosurgery, Department of Clinical Neuroscience, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland 6 Neuro- and Spine Center, Hirslanden Clinic St. Anna, Lucerne, Switzerland 1 2 Received: October 20, 2019 Revised: November 30, 2019 Accepted: December 2, 2019 See commentaries (1) “The Bull or the Horn – What Are Outcomes Data?” via https://doi.org/10.14245/ns.2040106.053; (2) “Does the Rise of Objective Measure of Functional Impairment Mean the Fall of PROMs?” via https://doi.org/10.14245/ ns.2040112.056; and (3) “A New Possible Standard in Evaluating Lower Extremity Motor Weakness” via https://doi. org/10.14245/ns.2040072.036. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 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. Copyright © 2020 by the Korean Spinal Neurosurgery Society Keywords: Objective functional impairment, Lumbar degenerative disc disease, Motor deficit, Paresis, Disability, Patient-reported outcome measure INTRODUCTION Lumbar degenerative disc disease (DDD) is a heterogenous condition that may lead to varying degrees of – but often considerable – low back and sciatic leg pain, disability, and loss of 270 www.e-neurospine.org health-related quality of life (HRQoL). Moreover, 40%–82% of patients suffering from lumbar DDD —in particular those with a lumbar disc herniation (LDH)—present with mild to severe lower extremity motor deficits (LEMDs) secondary to nerve root or cauda equina compression.1 Stienen MN, et al. Objective Functional Impairment in Patients With Motor Deficits The presence of LEMDs can be extremely frightening and distressing to patients,2 and it is reported that LEMDs strongly affect functional outcomes and rehabilitation potential.3 Other studies found, nonetheless, no association between LEMDs and patient-reported outcome measures (PROMs).4 Without question, LEMDs translate into higher disability but controversy remains, whether this disability resulting from LEMDs is evident and quantifiable in commonly used subjective PROMs, the current gold standard of outcome assessment. Over the last decades objective tests of function have increasingly complemented the comprehensive patient evaluation and those may be more sensitive towards disability resulting from LEMDs.5 However, no prior study evaluated whether the presence of LEMDs leads to more objective functional impairment (OFI) in these tests. We thus set out to explore the relationship between presence and severity of LEMDs and both the subjective (PROM-based) and OFI-based patient evaluation. Furthermore, in the discussion part of the manuscript, we perform an in-depth analysis of how disability is reflected by PROMs in previous literature and whether OFI should be assessed in patients with lumbar DDD. A representative case vignette is presented to illustrate the added benefit of the objective functional evaluation. (American Society of Anesthesiologists physical status classification risk score), working status, type of intended surgical procedure, as well as affected lumbar spinal segments and laterality. Muscle strength was tested systematically from the foot to the thigh. The motor function of the fibular muscles, the common extensor of the toes, the sural triceps, the long extensor of the hallux, the anterior tibial, the quadriceps, and the flexors of the hip were all tested. Presence and severity of LEMDs of segmentindicating muscles corresponding to the affected nerve root(s) were determined. For this, the L2 (and L3) roots were considered to correspond to the hip flexors, the L3 (and L4) roots to the knee extensors, the L4 (and L5) roots to the foot dorsiflexors, the L5 roots to the hallux extensor, and the S1 roots to the plantar flexors and foot eversors. As done in previous studies,1,4,6 we assessed LEMDs by manual testing and graded their severity according to the British Medical Research Council (BMRC) scale: • Grade (...truncated)