Percepción del paciente y cambio clínicamente significativo tras laminectomía cervical simple en la mielopatía cervical degenerativa: estudio de cohorte prospectivo

Abstract

Introduction

Validated clinical scales for cervical myelopathy (CM) assess disease severity and treatment efficacy, but often fail to capture the patient's subjective perception of treatment effects. This study aimed to correlate commonly used clinical scales for CM with patient-perceived outcomes after surgical treatment. Additionally, it sought to establish minimum clinically important difference (MCID) thresholds for scales strongly correlating with patient perception.

Patients and methods

A prospective, single-center observational study followed 47 patients with degenerative CM who underwent simple cervical laminectomy for one year. Patients were assessed using the mJOA, Nurick, cervical and brachial Visual Analogue Scales (VAS), the Neck Disability Index (IDC), and the EuroQol-5D (EQ5D). Patient perception of global effect (PGE) was assessed at 6 months and 1 year post-surgery using an anchor question asking if they perceived improvement, worsening, or no change. MCID was calculated using three anchor-based methods: mean difference, change difference, and the Youden index from Receiver Operating Characteristic (COR) curves. Definitive MCID thresholds were the average of these three methods.

Results

At the end of the follow-up, 25 patients (53.2%) had perceived clinical improvement with surgery, 15 (31.9%) had perceived no changes, and 7 (14.9%) had perceived worsening. The scales that showed the best correlation with patient perception were mJOA (η2 = 0.25; p = 0.002), Nurick (η2 = 0.19; p = 0.009), and NDI (η2 = 0.17; p = 0.016). The definitive MCID thresholds for improvement were an increase in score ≥ 1.5 points in mJOA, a reduction of ≥0.56 points in the Nurick scale, and a reduction of ≥5 points in NDI. The definitive MCID thresholds for worsening were an increase of ≤ 0.23 points or a loss of score in mJOA, an increase of ≥ 0.33 points in the Nurick scale, and an increase of ≥1.26 points in NDI. According to the MCID thresholds, the majority of patients achieved clinically significant improvement: 59.6% in mJOA (compared to 25.5% with worsening), 27.7% in the Nurick scale (compared to 6.4% who worsened), and 42.5% in the NDI (versus 19.1% who worsened).

Conclusion

Patient perception of outcome following cervical laminectomy for spondylotic cervical myelopathy significantly correlates with functional scales like mJOA, Nurick, and NDI. The MCID thresholds indicate that patients require a more substantial change to perceive improvement than worsening, highlighting an asymmetry in subjective perception of treatment effects. These findings support using MCID, anchored in subjective perceptions, as a complementary tool to interpret the clinical relevance of quantitative changes in clinical scales.