Effect of Duration of Symptoms on the Clinical and Functional Outcomes of Lumbar Microdiscectomy: A Randomized Controlled Trial

Impact of Preoperative Symptom Duration on Patient-reported Outcomes After Minimally Invasive Transforaminal Interbody Fusion for Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To assess the impact of preoperative symptom duration (PSD) on patient-reported outcome measures (PROMs) after minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) for degenerative spondylolisthesis (DSpond).

BACKGROUND

A prolonged duration of preoperative symptoms may implicate inferior long-term outcomes postsurgery. Prior studies of lumbar fusion recipients are limited by the inclusion of heterogeneous populations.

METHODS

A single-surgeon registry was retrospectively queried for privately insured patients who had undergone primary, elective, single-level MIS-TLIF for DSpond with a recorded symptom start date. Cohorts were formed by PSD: shorter duration (PSD <1 y) or greater duration (GD; PSD ≥1 y). PROMs evaluated included Patient-reported Outcomes Measurement Information System-Physical Function, Oswestry Disability Index, Visual Analog Scale-Back, Visual Analog Scale-Leg, and 9-item Patient Health Questionnaire. The magnitude of PROM (∆PROM) improvement from preoperative baseline to 6 weeks and final follow-up (∆PROM-FF) were compared between cohorts. Intercohort achievement rates of a minimum clinically important difference in each PROM were compared.

RESULTS

A total of 133 patients included 85 patients with GD cohort. There were no significant differences in pre hoc demographics and perioperative characteristics between cohorts, as well as preoperative, 6-week, or final follow-up PROMs between cohorts. Both cohorts demonstrated significant improvement in all PROMs at 6 weeks and final follow-up (P ≤ 0.049, all). There were no significant intercohort differences demonstrated in minimum clinically important difference achievement rates, ∆PROM-6W, or ∆PROM-FF in any PROM.

CONCLUSIONS

Regardless of the symptom duration before MIS-TLIF for DSpond, patients demonstrate significant improvement in physical function, pain, disability, and mental health. Patients with a GD of preoperative symptoms did not report inferior scores in any PROM domain. Patients with a GD of preoperative symptoms did not suffer inferior rates of clinically meaningful improvement after surgical intervention. These findings should be considered when counseling patients before surgical intervention for DSpond.

The Duration of Symptoms Influences Outcomes After Lumbar Microdiscectomies: A Michigan Spine Surgery Improvement Collaborative

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

We investigate whether duration of symptoms a patient experiences prior to lumbar microdiscectomy affects pain, lifestyle, and return to work metrics after surgery.

METHODS

A retrospective review of patients with a diagnosis of lumbar radiculopathy undergoing microdiscectomy was conducted using a statewide registry. Patients were grouped based on self-reported duration of symptoms prior to surgical intervention (Group 1: symptoms less than 3 months; Group 2: symptoms between 3 months and 1 year; and Group 3: symptoms greater than 1 year). Radicular pain scores, PROMIS PF Physical Function measure (PROMIS PF), EQ-5D scores, and return to work rates at 90 days, 1 year, and 2 years after surgery were compared using univariate and multivariate analysis.

RESULTS

There were 2408 patients who underwent microdiscectomy for lumbar disc herniation for radiculopathy with 532, 910, and 955 in Groups 1, 2, and 3, respectively. Postoperative leg pain was lower for Group 1 at 90 days, 1 year, and 2 years compared to Groups 2 and 3 (P < .05). Postoperative PROMIS PF and EQ-5D scores were higher for Group 1 at 90 days, 1 year, and 2 years compared to Groups 2 and 3 (P < .05).

CONCLUSION

Patients with prolonged symptoms prior to surgical intervention experience smaller improvements in postoperative leg pain, PROMIS PF, and EQ-5D than those who undergo surgery earlier. Patients undergoing surgery within 3 months of symptom onset have the highest rates of return to work at 1 year after surgery.

Understanding how the research question impacts trial design: Examples from discectomy trials

BACKGROUND

Formulating a pertinent research question is of the utmost importance in clinical research. An ill-conceived question may lead to an erroneous trial design, which may adversely affect the care of patients and provide uninformative or even misleading results.

METHODS

We review the research question of a randomized trial on the timing of lumbar discectomy. We compare the resulting design with other trials, real or hypothetical, that would have been more appropriate.

RESULTS

The RCT we examine randomly allocated patients to early or delayed surgery to answer a theoretical question of the effect of time on the efficacy of surgery. The trial was interpreted to have shown that early surgery was associated with better clinical and functional outcomes as compared to delayed surgery. This conclusion is clinically misleading. Valid comparisons between groups should be performed on intent-to-treat analyses and at the same time points after randomization (and not at a fixed follow-up period after surgery). The clinically pertinent comparison is not between the theoretical efficacy of surgery performed at various times, but between surgery and conservative management in patients presenting at various times. Better-designed trials on the clinical benefits of lumbar discectomy, including the treatment of chronic sciatica, have been published.

CONCLUSION

Theoretical research questions inspired from observational data can lead to erroneous trial design. Prospective randomized trials impact practice immediately: they are unique occasions to address clinical problems and optimize care under uncertainty in real time. However, they require the research question to be formulated with great care.

Depressed patients with greater symptom duration before MIS-TLIF do not report inferior outcomes

PURPOSE

Patients with preoperative depressive symptoms may demonstrate inferior patient-reported outcomes (PROs). The effect of preoperative symptom duration (SD) on PROs in this population has not been well-studied. We aim to assess the influence of preoperative SD on PROs in patients with low mental health scores prior to minimally invasive transforaminal interbody fusion (MIS-TLIF).

METHODS

Patients who had undergone elective, primary MIS-TLIF with preoperative SF-12 MCS score below 45.6, a previously established threshold for depression, were selected. Patients were divided into matched lesser duration (LD; SD<365 days) and greater duration (GD; SD≥365 days) cohorts. PROs were collected preoperatively and at 6-week/12-week/6-month/1-year postoperative periods. PROs included PROMIS-PF/ODI/VAS back/VAS leg/SF-12 MCS. PROs were compared within and between groups. Rates of achievement of minimal clinically important difference (MCID) were compared between groups.

RESULTS

One hundred twenty-two patients were included after matching cohorts. Patients in the LD cohort demonstrated improvement in PROMIS-PF at 12-weeks/6-month/1-year, and ODI/VAS back/VAS leg/SF-12 MCS at all postoperative periods (p≤0.024, all). Patients in the GD cohort demonstrated improvement in PROMIS-PF at 12-weeks/6-month/1-year, and ODI/VAS back/VAS leg/SF-12 MCS at all postoperative periods (p≤0.013, all). There were no differences in PROs or MCID achievement between cohorts at any period.

CONCLUSION

Patients with preoperative depressive symptoms undergoing MIS-TLIF, regardless of duration of preoperative symptoms, demonstrated improvements in physical function, disability, pain, and mental health domains. Patients with greater duration of preoperative symptoms did not report inferior outcomes at any period. Rates of clinically important improvements in all domains were favorable and similar between cohorts.

Impact of preoperative symptom duration in patients undergoing lateral lumbar interbody fusion

BACKGROUND

Few studies have examined the influence of preoperative symptom duration on clinical outcomes in patients undergoing lateral lumbar interbody fusion (LLIF) for degenerative conditions.

METHODS

Patients undergoing LLIF presenting with radiculopathy and/or neurogenic claudication were separated into two groups: preoperative symptom duration < 1-year (shorter duration) versus duration ≥ 1-year (longer duration). Patients undergoing surgery for trauma/malignancy/infection were excluded. Patient-reported outcome measures (PROMs) of Patient-Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF), 12-Item Short Form Physical/Mental Component Score (SF-12 PCS/MCS), Patient Health Questionnaire-9 (PHQ-9), visual analog scale (VAS) back/leg, and Oswestry Disability Index (ODI) were collected at preoperative and postoperative time points.

RESULTS

Eighty-two total patients, with 34 shorter-duration patients, were identified after propensity score matching for demographics. Longer-duration patients had higher estimated blood loss. All patients reported significant improvement in physical function, mental function, pain, and disability in at least one postoperative time point, except for SF-12 MCS in the shorter duration cohort. The longer duration cohort had higher MCID achievement in 12-week VAS back.

CONCLUSION

Patients undergoing LLIF demonstrated significant postoperative improvement in physical function, mental function, pain, and disability outcomes independent of preoperative symptom duration. Both cohorts, when compared by preoperative symptom duration, demonstrated similar postoperative PROM scores. Patients with longer preoperative symptom duration had higher 12-week leg pain MCID achievement. These findings suggest that delayed time to surgery may not lead to inferior clinical outcomes in patients undergoing LLIF for degenerative conditions.