Low-back pain after lumbar discectomy for disc herniation: what can you tell your patient?

Christian Iorio-Morin Division of Neurosurgery, Department of Surgery, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec;

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Charles G. Fisher Division of Spine Surgery, Vancouver General Hospital and the University of British Columbia, Vancouver, British Columbia;

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Edward Abraham Department of Orthopaedic Surgery, Saint John Regional Hospital, Saint John, New Brunswick;
Department of Orthopaedic Surgery, Dalhousie University, Halifax, Nova Scotia;

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Andrew Nataraj Division of Neurosurgery, Department of Surgery, University of Alberta Hospital, Edmonton, Alberta;

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Najmedden Attabib Department of Orthopaedic Surgery, Saint John Regional Hospital, Saint John, New Brunswick;
Department of Orthopaedic Surgery, Dalhousie University, Halifax, Nova Scotia;

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Jerome Paquet Department of Neurological Sciences, Université Laval, Quebec;

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Thomas Guy Hogan Department of Orthopedic Surgery, Memorial University, St. John’s, Newfoundland;

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Christopher S. Bailey Division of Orthopaedics, Department of Surgery, Schulich School of Medicine and Dentistry, Western University, London, Ontario;

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Henry Ahn Division of Orthopaedic Surgery, University of Toronto, Toronto, Ontario;

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Michael Johnson Section of Orthopaedic Surgery, Health Science Centre, Winnipeg, Manitoba;

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Eden A. Richardson Canadian Spine Outcomes and Research Network, Ontario; and
Canadian Spine Outcomes and Research Network, Ontario; and

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Neil Manson Department of Orthopaedic Surgery, Saint John Regional Hospital, Saint John, New Brunswick;
Department of Orthopaedic Surgery, Dalhousie University, Halifax, Nova Scotia;
Department of Orthopedic Surgery, Memorial University, St. John’s, Newfoundland;

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Ken Thomas Department of Surgery, Department of Clinical Neurosciences, University of Calgary, Alberta, Canada

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Y. Raja Rampersaud Division of Orthopaedic Surgery, University of Toronto, Toronto, Ontario;

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Hamilton Hall Division of Orthopaedic Surgery, University of Toronto, Toronto, Ontario;

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Nicolas Dea Division of Spine Surgery, Vancouver General Hospital and the University of British Columbia, Vancouver, British Columbia;

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OBJECTIVE

Lumbar discectomy (LD) is frequently performed to alleviate radicular pain resulting from disc herniation. While this goal is achieved in most patients, improvement in low-back pain (LBP) has been reported inconsistently. The goal of this study was to characterize how LBP evolves following discectomy.

METHODS

The authors performed a retrospective analysis of prospectively collected patient data from the Canadian Spine Outcomes and Research Network (CSORN) registry. Patients who underwent surgery for lumbar disc herniation were eligible for inclusion. The primary outcome was a clinically significant reduction in the back pain numerical rating scale (BPNRS) assessed at 12 months. Binary logistic regression was used to model the relationship between the primary outcome and potential predictors.

RESULTS

There were 557 patients included in the analysis. The chief complaint was radiculopathy in 85%; 55% of patients underwent a minimally invasive procedure. BPNRS improved at 3 months by 48% and this improvement was sustained at all follow-ups. LBP and leg pain improvement were correlated. Clinically significant improvement in BPNRS at 12 months was reported by 64% of patients. Six factors predicted a lack of LBP improvement: female sex, low education level, marriage, not working, low expectations with regard to LBP improvement, and a low BPNRS preoperatively.

CONCLUSIONS

Clinically significant improvement in LBP is observed in the majority of patients after LD. These data should be used to better counsel patients and provide accurate expectations about back pain improvement.

ABBREVIATIONS

BPNRS = back pain numerical rating scale; CSORN = Canadian Spine Outcomes and Research Network; LBP = low-back pain; LD = lumbar discectomy; LPNRS = leg pain numerical rating scale; MCID = minimal clinically important difference; MIS = minimally invasive surgery.

OBJECTIVE

Lumbar discectomy (LD) is frequently performed to alleviate radicular pain resulting from disc herniation. While this goal is achieved in most patients, improvement in low-back pain (LBP) has been reported inconsistently. The goal of this study was to characterize how LBP evolves following discectomy.

METHODS

The authors performed a retrospective analysis of prospectively collected patient data from the Canadian Spine Outcomes and Research Network (CSORN) registry. Patients who underwent surgery for lumbar disc herniation were eligible for inclusion. The primary outcome was a clinically significant reduction in the back pain numerical rating scale (BPNRS) assessed at 12 months. Binary logistic regression was used to model the relationship between the primary outcome and potential predictors.

RESULTS

There were 557 patients included in the analysis. The chief complaint was radiculopathy in 85%; 55% of patients underwent a minimally invasive procedure. BPNRS improved at 3 months by 48% and this improvement was sustained at all follow-ups. LBP and leg pain improvement were correlated. Clinically significant improvement in BPNRS at 12 months was reported by 64% of patients. Six factors predicted a lack of LBP improvement: female sex, low education level, marriage, not working, low expectations with regard to LBP improvement, and a low BPNRS preoperatively.

CONCLUSIONS

Clinically significant improvement in LBP is observed in the majority of patients after LD. These data should be used to better counsel patients and provide accurate expectations about back pain improvement.

Lumbar discectomy (LD) is among the most frequent surgical procedures performed in North America. Its efficacy is supported by multiple trials which have consistently shown improvement in radicular pain and functional status relative to baseline.1–4 Low-back pain (LBP) is a frequent comorbid symptom in patients with disc herniation. While many studies have suggested that LBP could improve following LD,5–11 some authors reported that up to 32% of patients experienced LBP worsening, presumably resulting from accelerated degenerative changes.12,13 This provided a rationale for trials of sequestrectomies14 and the development of minimally invasive surgery (MIS) procedures,15,16 as well as to the use of fusion.17 Trials of these new surgical techniques have focused on demonstrating improvement in radicular pain, with few studies specifically assessing LBP as a primary outcome.18–20

When providing expectation counseling to patients presenting with radiculopathy secondary to a herniated disc, many surgeons will advise patients to expect a much greater likelihood of relief of radiculopathy compared to relief of LBP.21 Given the improvement in LBP observed in a number of trials, such counseling might be overly pessimistic, and inaccurate expectation management may lead to suboptimal outcomes. The goal of this study was to better characterize how LBP changes following discectomy and identify factors associated with back pain improvement.

Methods

Study Design, Setting, and Participants

We performed a retrospective analysis of prospectively collected registry data through the Canadian Spine Outcomes and Research Network (CSORN). CSORN is a group of over 50 neurosurgical and orthopedic spine surgeons from 18 tertiary care academic and nonacademic hospitals across Canada who prospectively collect data on patients with spinal conditions. Patients were enrolled in CSORN during their initial clinical assessment by their treating surgeon and patient-reported data were collected at the initial assessment, at the time of surgery, and at 3, 12, and 24 months postoperatively. All patients in the registry were screened for eligibility. The inclusion criteria were the following: 1) having a principal diagnosis of lumbar disc herniation and 2) having undergone a surgery which included an LD. Patients were excluded if they underwent fusion, or if no LBP assessment was recorded preoperatively or postoperatively.

Research Ethics Board Approval

All participating sites obtained Research Ethics Board (REB) approval prior to any data collection. Written informed consent was obtained from all participating patients.

Variables and Outcomes

Among the variables recorded in the registry, we extracted sociodemographic data, clinical characteristics, surgical parameters, and outcome data, as detailed in Tables 14. Variables related to patients’ motivations to undergo surgery and expectations on the outcome were assessed using the North American Spine Society instrument for lumbar spine outcome assessment.22 Pain was documented as a patient-reported outcome classified as either “back pain” or “leg pain” and presented as such to the patient without any more specific definition. Pain was quantified using the back pain numerical rating scale (BPNRS) and leg pain numerical rating scale (LPNRS) preoperatively and at 3, 12, and 24 months postoperatively and analyzed as ordinal variables.

TABLE 1.

Cohort demographics

Value
Sex (n = 557)
 Female256 (46%)
 Male301 (54%)
Age, yrs (n = 536)42 ± 13 (17–89)
BMI (n = 536)27 ± 5 (14–52)
Smoking status (n = 548)
 Nonsmoker437 (80%)
 Smoker111 (20%)
Exercise (n = 549)
 Never246 (45%)
 Yes303 (55%)
Education (n = 540)
 Less than high school39 (7%)
 High school114 (21%)
 Technical school101 (19%)
 College/university286 (53%)
Marital status (n = 554)
 Single/widowed113 (20%)
 Divorced/separated40 (7%)
 Married/engaged/common law401 (72%)
Working status (n = 532)
 Not working186 (35%)
 Student/retiree/homemaker86 (16%)
 Working260 (49%)
Compensation (n = 509)
 No special compensation334 (66%)
 Claims or workers’ compensation175 (34%)

Values are presented as number (%) of patients or mean ± SD (range).

TABLE 2.

Clinical presentation

Value
Chief complaint (n = 557)
 Radiculopathy470 (85%)
 Back pain68 (12%)
 Neurogenic claudication13 (2%)
 Other6 (1%)
Preop back pain (n = 557)
 Absent (BPNRS 0)10 (2%)
 Present (BPNRS >0) 547 (98%)
Time w/ condition (n = 556)
  <6 wks9 (2%)
 6–12 wks37 (7%)
 3–6 mos87 (15%)
 6–12 mos113 (20%)
 1–2 yrs98 (18%)
  >2 yrs212 (38%)
Use of medication for condition (n = 556)504 (91%)
Past spinal injection (n = 534)170 (32%)
Previous spine op (n = 556)66 (12%)
Primary reason to undergo op (n = 557)
 Reduce pain248 (44%)
 Improve general physical capacity135 (24%)
 Fear of worsening75 (13%)
 Keep independence58 (10%)
 Physician recommendation51 (9%)
Most important change expected from op (n = 532)
 Improving leg pain209 (39%)
 Improving back pain107 (20%)
 Improving general physical capacity109 (21%)
 Others107 (20%)
Expected improvement in leg pain (n = 545)
 Much better413 (76%)
 Better108 (20%)
 Somewhat better20 (3%)
 No change4 (1%)
Expected improvement in back pain (n = 536)
 Much better298 (55%)
 Better151 (28%)
 Somewhat better66 (13%)
 No change21 (4%)

Values are presented as number (%) of patients.

TABLE 3.

Surgical procedure

Value
Level of discectomy (n = 557)
 L1–22 (0.4%)
 L2–38 (1.4%)
 L3–421 (3.8%)
 L4–5206 (37%)
 L5–S1249 (44.7%)
 Unknown/multiple levels71 (12.7%)
Revision op (n = 557)21 (4%)
MIS procedure (n = 557)304 (55%)
Approach (n = 557)
 Posterior paraspinal265 (48%)
 Posterior midline236 (42%)
 Other56 (10%)
Arthroplasty (n = 557)47 (8%)

Values are presented as number (%) of patients.

TABLE 4.

Predictors of clinically significant improvement in BPNRS at 12 months

VariableMultivariate AnalysisUnivariate Analysis p Value
OR (95% CI)p Value
Simple discectomy (relative to arthroplasty)4.067 (0.427–38.764)0.2230.151
Open procedure (relative to MIS procedure)0.376 (0.122–1.162)0.0890.151
1st op (relative to revision op)1.961 (0.272–14.167)0.5040.364
No. of levels0.596 (0.245–1.450)0.2540.229
Education (relative to university) 0.0120.013
 Less than high school0.100 (0.021–0.465)0.003
 High school0.356 (0.134–0.946)0.028
 Technical school0.805 (0.316–2.053)0.649
Marital status (relative to single) 0.0120.050
 Divorced/separated0.690 (0.121–3.941)0.676
 Married/common law0.241 (0.088–0.657)0.005
Work status (relative to working) 0.0010.001
 Not working0.185 (0.079–0.434)0.0005
 Student/retired0.469 (0.161–1.367)0.165
Back pain expected to improve1.164 (1.061–2.607)0.0260.002
Lack of claims or workers’ compensation1.182 (0.531–2.632)0.6820.320
Initial BPNRS1.417 (1.199–1.674)0.00050.0005
Age at op0.994 (0.962–1.027)0.7220.169
BMI at op 0.796
Being female0.374 (0.182–0.772)0.008 0.349
Smoking 0.437
Exercising 0.643
Time spent preop w/ condition0.798 (0.596–1.068)0.1290.540
Preop medication for back problem 0.544
No previous spinal injection1.761 (0.818–3.794)0.1480.061
Most important change to consider op successful 0.690

Multivariate (binomial logistic regression) and univariate analyses of factors predicting a clinically significant improvement in BPNRS at the 12-month follow-up. Improvement in back pain was less likely in patients who were married, not working, with a lower level of education, with lower expectations regarding back pain improvement, or with less initial back pain. Being male predicted a larger improvement in BPNRS than being female in the multivariate analysis, although this difference was not evident in the univariate analysis, presumably because of confounding from the other variables. Boldface type indicates statistical significance.

The primary outcome was having a clinically significant improvement in BPNRS at 12 months following LD. This was defined as having a decrease in BPNRS (relative to the preoperative value) greater than or equal to a minimal clinically important difference (MCID) of 2.23 Secondary outcomes were having a clinically significant improvement in BPNRS at 3 and 24 months as well as the absolute BPNRS and LPNRS values at 3, 12, and 24 months. Finally, for patients with BPNRS values available at all 3 follow-ups, we classified patients in one of five BPNRS response patterns. Early responders were patients with improvement (defined as reaching or exceeding the MCID) at 3 months which was sustained at 24 months. Late responders were patients who had no improvement at 3 months but had improved at 24 months. Transient responders were patients who had improvement at 3 or 12 months, but who were back to baseline at 24 months. Nonresponders were patients who did not improve at any follow-up. Worsened classification was used for patients who experienced a clinically significant increase in BPNRS at any follow-up.

Statistical Analysis

Prior to the analysis, range checks were performed on all variables and errors in data entry were corrected. Descriptive statistics of continuous variables are presented using the distribution’s median ± standard deviation with range, whereas those of categorical variables are presented using frequency tables with total number of events and valid percentages. Follow-up rates were computed by dividing patients who underwent follow-up with the number of patients eligible for this follow-up (i.e. for the 2-year follow-up, patients who were deceased or who underwent surgery less than 2 years prior are excluded from the denominator). The total sample size was 557, except for variables for which data were missing, in which case the variable-specific sample size is provided. Baseline and outcome variables were compared between patients with complete follow-up data and patients with missing assessments by using an unpaired t-test for continuous variables and a chi-square test of independence for categorical variables, with Bonferroni correction for multiple comparisons.

The difference in BPNRS or LPNRS at each follow-up relative to the preoperative assessment was computed using a paired-sample t-test. The correlation between the BPNRS response pattern and the change in LPNRS was tested using Spearman’s rank-order correlation. The impact of each variable on the primary outcome was assessed in a univariate analysis using an unpaired t-test for continuous variables and a chi-square test of independence for categorical variables. The multivariate analysis was performed using a binomial logistic regression. All variables presented in Tables 13 were considered for inclusion. The five variables with the highest p values in the univariate analysis (BMI, smoking, exercising, use of preoperative medication, and most important expected change after surgery) were removed to keep the number of cases per independent variable > 15. One variable (chief complaint) was removed because it introduced significant multicollinearity. All continuous independent variables were found to be linearly related to the logit of the dependent variable, as assessed using the Box-Tidwell procedure.24 There were 7 cases with a studentized residual greater than 2.5 SDs and these were kept in the analysis.

Statistical significance was defined at p < 0.05. Statistical analyses were performed using IBM SPSS Statistics, version 25 (IBM Corp.) and figures were rendered using Prism 7.0d (GraphPad Software Inc.) and Adobe Illustrator CS6 (Adobe Systems Inc.).

Results

Cohort Demographics and Clinical Characteristics

Patient selection within the CSORN registry was performed as detailed in Fig. 1, yielding a final data set of 557 patients. Follow-up data were available for 539 patients (97%) at 3 months, 283 (71% of 397 eligible) at 12 months, and 107 (60% of 177 eligible) at 24 months. There were no baseline differences between patients with complete follow-ups and those with missing assessments on any of the variables listed in Tables 13.

FIG. 1.
FIG. 1.

Patient selection flowchart. Detail of patient selection within the CSORN registry. Data capture was performed in October 2017.

The cohort demographics are presented in Table 1. The patients included in the analysis underwent surgery between February 2013 and May 2017 in one of 17 Canadian centers in 8 provinces. The median age at the time of surgery was 42 ± 13 years, with most patients being nonsmoking (80%), married (72%), working (49%), and without workers’ compensation (66%). The clinical presentation data are detailed in Table 2. Briefly, the chief complaint was radiculopathy (85%) or back pain (12%), often present for > 1 year (56%). Only 10 patients (2%) reported not having any LBP preoperatively. Most patients (91%) used medication for their symptoms and 32% had previously undergone spinal injections. The primary reasons given by patients for undergoing surgery were pain reduction (44%), improving general physical capacity (24%), and fear of worsening (13%). The most important change expected from surgery was an improvement in leg pain for 39%, back pain for 20%, and general physical capacity for 21% of patients. Back pain improvement was specifically expected by 96% of patients, even though this might not have been the goal of the surgery.

Surgical Procedures

The most frequently operated levels were L4–5 (37%) and L5–S1 (45%) (Table 3). Only 13% of patients underwent multilevel procedures. The discectomy was performed through posterior paraspinal (48%) or posterior midline (42%) approaches in most cases, with 55% of surgeries using MIS techniques. While 47 patients (8%) underwent arthroplasty, no patient underwent fusion.

Back Pain Following LD

Patient-reported back pain improved by 48% ± 2% (from a mean of 6.4% ± 0.1% to 3.3% ± 0.1%) at 3 months postoperatively (Fig. 2). This improvement was statistically significant (p < 0.0005) and was maintained at the 12- and 24-month follow-ups. Improvement in back pain mirrored that in leg pain when both were assessed using numerical rating scales (Fig. 2). Improvement in back pain was clinically significant (exceeding the MCID of 2) at 3, 12, and 24 months in 71%, 64%, and 71% of patients, respectively (Fig. 3). At these 3 follow-up times, clinically significant worsening occurred in 3%–8% of patients. Patients lost to follow-up did not have better or worse pain outcomes than patients with complete assessments at all time points.

FIG. 2.
FIG. 2.

Evolution of back and leg pain following LD. BPNRS (green) and LPNRS (yellow) at each clinical assessment. The difference between the baseline and all follow-ups was statistically significant for both BPNRS and LPNRS. Error bars represent the SEM. Bars were omitted when the SEM was < 0.15. BPNRS and LPNRS curves were offset on the x-axis to facilitate reading. Figure is available in color online only.

FIG. 3.
FIG. 3.

Proportion of patients reporting change in back pain following LD. With an MCID of 2, 64%–71% of patients reported improvement in BPNRS during follow-up. Figure is available in color online only.

Response Patterns

Among the 84 patients (15% of the cohort) for whom BPNRS data were available at all follow-ups, 54% were early responders (improvement at 3 months sustained at 24 months), 9% were late responders (no improvement at 3 months, but improved at 24 months), 12% were transient responders (improvement at 3 or 12 months, but not better than preoperative at 24 months), 9% had no improvement at any time, and 16% worsened at any time. The back pain response pattern correlated with the improvement in LPNRS at all follow-ups (r s = 0.5, p < 0.0005).

Predictors of Back Pain Improvement

A binomial logistic regression was performed to assess the impact of demographic and surgical parameters on back pain improvement at 12 months (see the Methods section and Table 4). A total of 210 cases (38% of cohort) with no missing data were used. The logistic regression model was statistically significant, chi-square(21) = 85.231, p < 0.0005. The model explained 43% (Nagelkerke R2) of the variance in clinically significant back pain improvement and correctly classified 77% of cases. Of the 14 predictor variables tested, 6 were statistically significant. Improvement in back pain was less likely in females, patients who were married, not working, with a lower level of education, with lower expectations regarding back pain improvement, or with less initial back pain. Patients who underwent MIS procedures showed a nonsignificant trend toward better improvement in back pain relative to open surgeries. Arthroplasties, revision surgeries, age, number of levels, workers’ compensation, time with condition, and previous spinal injections were all not associated with the primary outcome.

Discussion

Will Back Pain Improve Following Lumbar Discectomy?

In our large cohort of patients who underwent LD for disc herniation, back pain improved by 48% ± 2% and this improvement was clinically significant for 64%–71% of patients (Fig. 3). Improvement in back pain mirrored that in leg pain (Fig. 2). Worsening of back pain at any time occurred in only 16% of patients, as opposed to the 32% rate reported by other authors.12,13 Together, these data suggest that LBP improves in the majority of patients following surgery for herniated discs and that this improvement is sustained after 12 months—an observation also made in the 8-year follow-up of the SPORT cohort.25 This result is significant and allows spine surgeons to better counsel patients about what to expect from this surgery. As shown in this study, patients being overly pessimistic might lead to suboptimal outcomes and accurate expectation management is thus desirable.

Six factors predicting a lack of LBP improvement were identified: having low expectations with regard to back pain improvement, a low level of back pain preoperatively, not working, a lower level of education, female sex, and being married.

In our series, 304 patients (55%) underwent MIS procedures. There was no statistically significant difference in outcome compared to patients who underwent conventional open LD, although a nonsignificant trend toward better improvement was observed (p = 0.089). While some surgeons might have selected specific patients for MIS procedures and others for open procedures, many surgeons perform only one or the other and as such, the selection bias is probably less significant for the MIS subgroup than for more complex variables such as education or time with the condition. Given that standard open LD is a relatively simple and limited surgery, the benefit of MIS procedures might be better appreciated in more complex, multilevel procedures. For simple LD, however, because statistical significance could not be achieved in our cohort of over 500 patients, the clinical benefit of MIS procedures on LBP is probably extremely limited.

What Is Back Pain?

Spine surgeons usually try to distinguish LBP (axial pain) from radicular pain because these are postulated as possibly resulting from two different processes and thus to respond differently to treatment. Whereas radicular pain is frequently caused by nerve root inflammation resulting from compression and relieved by decompression, the cause of LBP is often more difficult to identify and treat. Patient-reported outcomes such as the BPNRS are sensitive to what the patient considers to be LBP, regardless of surgeon definitions. Radicular pain resulting from nerve root compression, radiating from the back to the buttock, could therefore be considered LBP by many patients. The perfect correlation between BPNRS and LPNRS scores in this study (Fig. 2) highlights this issue. Whether the symptom(s) patients reported as LBP represent radiculopathy, mechanical pain from instability, or simply nociceptive pain resulting from a torn annulus fibrosus is unclear. What is clear, however, is that what patients consider as LBP improved significantly with surgery, no matter the etiology.

Study Strengths and Limitations

We performed a large study of LD for which LBP was reported as a primary outcome. The use of a national registry ensured a diverse cohort representative of the current variability in practice. Patients were operated on by surgeons from 17 centers in 8 provinces using a mix of procedures, including MIS techniques, midline and paraspinal approaches, arthroplasty, etc.; this supports the external validity of our results.

CSORN is an observational registry study; therefore, selection bias inevitably occurred. Selection bias due to loss to follow-up might also have occurred, enriching the registry in patients with worse outcomes who are never discharged or keep coming back. In our series, only 107 patients (60% of 177 eligible) had a documented 24-month follow-up. While improvements have been implemented in the registry to improve this rate in the future, we believe this attrition is representative of clinical practice, in which most surgeons do not follow successful LD patients for more than 1 year. Moreover, Ayling et al., in an analysis of CSORN data, analyzed the time course of recovery after surgery for common degenerative spinal conditions and found that patient-reported outcomes typically plateau at 3 to 12 months.26 Together with the observation that BPNRS and LPNRS do not change between 3 and 24 months (Fig. 2), these data support our choice of primary outcome at 12 months as a good compromise between long-term outcome data and a reliable number of patients for analysis.

Conclusions

LBP improves after LD in the majority of patients. This improvement is measurable at 3 months and sustained at 12 and 24 months. Clinical factors associated with an absence of back pain improvement are low expectations regarding back pain improvement, a low level of preoperative pain, not working, a low level of education, female sex, and being married. This information could be used to better consent and better manage expectations in patients undergoing LD.

Acknowledgments

We acknowledge the contribution of every surgeon and the research staff and patients at each participating site, without whom this work would not have been possible. We also thank Jean Leblond from the Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale of Université Laval for his sound statistical advice.

Disclosures

Dr. Fisher: consultant for NuVasive and Medtronic; royalties from Medtronic; fellowship support paid to institution from Medtronic and AO Spine. Dr. Johnson: clinical or research support for study described (includes equipment or material) from Stryker. Dr. Manson: consultant for Medtronic Canada; support of non–study-related clinical or research effort overseen by author from Medtronic Canada. Dr. Rampersaud: royalties from Medtronic; consultant for Medtronic; ownership in Arthur Health. Dr. Dea: direct stock ownership in Medtronic; consultant for Stryker; speakers bureau for Baxter; honoraria from Medtronic.

Author Contributions

Conception and design: Dea, Iorio-Morin, Fisher, Manson, Thomas, Rampersaud, Hall. Acquisition of data: McIntosh. Analysis and interpretation of data: Dea, Iorio-Morin, McIntosh. Drafting the article: Dea, Iorio-Morin, Fisher, Abraham, Nataraj, Attabib, Paquet, Hogan, Bailey, Ahn, Johnson, Manson, Thomas, Rampersaud, Hall. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Dea. Statistical analysis: McIntosh. Study supervision: Dea, Fisher.

Supplemental Information

Previous Presentations

Presented at the Canadian Spine Society Conference, Banff, Alberta, Canada, February 2018; the North American Spine Society annual meeting, Los Angeles, CA, September 2018; the Congress of Neurological Surgeons Annual Meeting, Houston, TX, October 2018; and at the Global Spine Annual Meeting, Toronto, May 2019.

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  • 7

    Gibson JNA, Subramanian AS, Scott CEH. A randomised controlled trial of transforaminal endoscopic discectomy vs microdiscectomy. Eur Spine J. 2017;26(3):847856.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Gautschi OP, Smoll NR, Joswig H, et al. Influence of age on pain intensity, functional impairment and health-related quality of life before and after surgery for lumbar degenerative disc disease. Clin Neurol Neurosurg. 2016;150:3339.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Pitsika M, Thomas E, Shaheen S, Sharma H. Does the duration of symptoms influence outcome in patients with sciatica undergoing micro-discectomy and decompressions?. Spine J. 2016;16(4)(suppl):S21S25.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Strömqvist F, Strömqvist B, Jönsson B, Karlsson MK. Inferior outcome of lumbar disc surgery in women due to inferior preoperative status: a prospective study in 11,237 patients. Spine (Phila Pa 1976).2016;41(15):12471252.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Owens RK II, Carreon LY, Bisson EF, et al. Back pain improves significantly following discectomy for lumbar disc herniation. Spine J. 2018;18(9):16321636.

  • 12

    McGirt MJ, Ambrossi GLG, Datoo G, et al. Recurrent disc herniation and long-term back pain after primary lumbar discectomy: review of outcomes reported for limited versus aggressive disc removal. Neurosurgery. 2009;64(2):338345.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Parker SL, Xu R, McGirt MJ, et al. Long-term back pain after a single-level discectomy for radiculopathy: incidence and health care cost analysis. J Neurosurg Spine. 2010;12(2):178182.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Ran J, Hu Y, Zheng Z, et al. Comparison of discectomy versus sequestrectomy in lumbar disc herniation: a meta-analysis of comparative studies. PLoS One. 2015;10(3):e0121816.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Cong L, Zhu Y, Tu G. A meta-analysis of endoscopic discectomy versus open discectomy for symptomatic lumbar disk herniation. Eur Spine J. 2016;25(1):134143.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    He J, Xiao S, Wu Z, Yuan Z. Microendoscopic discectomy versus open discectomy for lumbar disc herniation: a meta-analysis. Eur Spine J. 2016;25(5):13731381.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Wang JC, Dailey AT, Mummaneni PV, et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 8: Lumbar fusion for disc herniation and radiculopathy. J Neurosurg Spine. 2014;21(1):4853.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Toyone T, Tanaka T, Kato D, Kaneyama R. Low-back pain following surgery for lumbar disc herniation. A prospective study. J Bone Joint Surg Am. 2004;86(5):893896.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Pearson AM, Blood EA, Frymoyer JW, et al. SPORT lumbar intervertebral disk herniation and back pain: does treatment, location, or morphology matter? Spine. (Phila Pa 1976).2008;33(4):428435.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Ohtori S, Yamashita M, Yamauchi K, et al. Low back pain after lumbar discectomy in patients showing endplate modic type 1 change. Spine (Phila Pa 1976).2010;35(13):E596E600.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Kreiner DS, Hwang SW, Easa JE, et al. An evidence-based clinical guideline for the diagnosis and treatment of lumbar disc herniation with radiculopathy. Spine J. 2014;14(1):180191.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Daltroy LH, Cats-Baril WL, Katz JN, et al. The North American spine society lumbar spine outcome assessment Instrument: reliability and validity tests. Spine (Phila Pa 1976).1996;21(6):741749.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Ostelo RWJG, Deyo RA, Stratford P, et al. Interpreting change scores for pain and functional status in low back pain: towards international consensus regarding minimal important change. Spine (Phila Pa 1976).2008;33(1):9094.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Box GEP, Tidwell PW. Transformation of the independent variables. Technometrics. 1962;4(4):531550.

  • 25

    Lurie JD, Tosteson TD, Tosteson ANA, et al. Surgical versus nonoperative treatment for lumbar disc herniation: eight-year results for the Spine Patient Outcomes Research Trial. Spine (Phila Pa 1976).2014;39(1):316.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26

    Ayling OGS, Ailon T, McIntosh G, et al. Clinical outcomes research in spine surgery: what are appropriate follow-up times?. J Neurosurg Spine. 2018;30(3):397404.

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Images and illustration from Akinduro et al. (pp 834–843). Copyright Tito Vivas-Buitrago. Published with permission.
  • FIG. 1.

    Patient selection flowchart. Detail of patient selection within the CSORN registry. Data capture was performed in October 2017.

  • FIG. 2.

    Evolution of back and leg pain following LD. BPNRS (green) and LPNRS (yellow) at each clinical assessment. The difference between the baseline and all follow-ups was statistically significant for both BPNRS and LPNRS. Error bars represent the SEM. Bars were omitted when the SEM was < 0.15. BPNRS and LPNRS curves were offset on the x-axis to facilitate reading. Figure is available in color online only.

  • FIG. 3.

    Proportion of patients reporting change in back pain following LD. With an MCID of 2, 64%–71% of patients reported improvement in BPNRS during follow-up. Figure is available in color online only.

  • 1

    Buttermann GR. Treatment of lumbar disc herniation: epidural steroid injection compared with discectomy. A prospective, randomized study. J Bone Joint Surg Am. 2004;86(4):670679.

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  • 2

    Osterman H, Seitsalo S, Karppinen J, Malmivaara A. Effectiveness of microdiscectomy for lumbar disc herniation: a randomized controlled trial with 2 years of follow-up. Spine (Phila Pa 1976).2006;31(21):24092414.

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  • 3

    Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. JAMA. 2006;296(20):24412450.

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  • 4

    Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT) observational cohort. JAMA. 2006;296(20):24512459.

    • Crossref
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  • 5

    Parker SL, Mendenhall SK, Godil SS, et al. Incidence of low back pain after lumbar discectomy for herniated disc and its effect on patient-reported outcomes. Clin Orthop Relat Res. 2015;473(6):19881999.

    • Crossref
    • PubMed
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    • Export Citation
  • 6

    Bono CM, Leonard DA, Cha TD, et al. The effect of short (2-weeks) versus long (6-weeks) post-operative restrictions following lumbar discectomy: a prospective randomized control trial. Eur Spine J. 2017;26(3):905912.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Gibson JNA, Subramanian AS, Scott CEH. A randomised controlled trial of transforaminal endoscopic discectomy vs microdiscectomy. Eur Spine J. 2017;26(3):847856.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Gautschi OP, Smoll NR, Joswig H, et al. Influence of age on pain intensity, functional impairment and health-related quality of life before and after surgery for lumbar degenerative disc disease. Clin Neurol Neurosurg. 2016;150:3339.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Pitsika M, Thomas E, Shaheen S, Sharma H. Does the duration of symptoms influence outcome in patients with sciatica undergoing micro-discectomy and decompressions?. Spine J. 2016;16(4)(suppl):S21S25.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Strömqvist F, Strömqvist B, Jönsson B, Karlsson MK. Inferior outcome of lumbar disc surgery in women due to inferior preoperative status: a prospective study in 11,237 patients. Spine (Phila Pa 1976).2016;41(15):12471252.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Owens RK II, Carreon LY, Bisson EF, et al. Back pain improves significantly following discectomy for lumbar disc herniation. Spine J. 2018;18(9):16321636.

  • 12

    McGirt MJ, Ambrossi GLG, Datoo G, et al. Recurrent disc herniation and long-term back pain after primary lumbar discectomy: review of outcomes reported for limited versus aggressive disc removal. Neurosurgery. 2009;64(2):338345.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Parker SL, Xu R, McGirt MJ, et al. Long-term back pain after a single-level discectomy for radiculopathy: incidence and health care cost analysis. J Neurosurg Spine. 2010;12(2):178182.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Ran J, Hu Y, Zheng Z, et al. Comparison of discectomy versus sequestrectomy in lumbar disc herniation: a meta-analysis of comparative studies. PLoS One. 2015;10(3):e0121816.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Cong L, Zhu Y, Tu G. A meta-analysis of endoscopic discectomy versus open discectomy for symptomatic lumbar disk herniation. Eur Spine J. 2016;25(1):134143.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    He J, Xiao S, Wu Z, Yuan Z. Microendoscopic discectomy versus open discectomy for lumbar disc herniation: a meta-analysis. Eur Spine J. 2016;25(5):13731381.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Wang JC, Dailey AT, Mummaneni PV, et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 8: Lumbar fusion for disc herniation and radiculopathy. J Neurosurg Spine. 2014;21(1):4853.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Toyone T, Tanaka T, Kato D, Kaneyama R. Low-back pain following surgery for lumbar disc herniation. A prospective study. J Bone Joint Surg Am. 2004;86(5):893896.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Pearson AM, Blood EA, Frymoyer JW, et al. SPORT lumbar intervertebral disk herniation and back pain: does treatment, location, or morphology matter? Spine. (Phila Pa 1976).2008;33(4):428435.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Ohtori S, Yamashita M, Yamauchi K, et al. Low back pain after lumbar discectomy in patients showing endplate modic type 1 change. Spine (Phila Pa 1976).2010;35(13):E596E600.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Kreiner DS, Hwang SW, Easa JE, et al. An evidence-based clinical guideline for the diagnosis and treatment of lumbar disc herniation with radiculopathy. Spine J. 2014;14(1):180191.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Daltroy LH, Cats-Baril WL, Katz JN, et al. The North American spine society lumbar spine outcome assessment Instrument: reliability and validity tests. Spine (Phila Pa 1976).1996;21(6):741749.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Ostelo RWJG, Deyo RA, Stratford P, et al. Interpreting change scores for pain and functional status in low back pain: towards international consensus regarding minimal important change. Spine (Phila Pa 1976).2008;33(1):9094.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Box GEP, Tidwell PW. Transformation of the independent variables. Technometrics. 1962;4(4):531550.

  • 25

    Lurie JD, Tosteson TD, Tosteson ANA, et al. Surgical versus nonoperative treatment for lumbar disc herniation: eight-year results for the Spine Patient Outcomes Research Trial. Spine (Phila Pa 1976).2014;39(1):316.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26

    Ayling OGS, Ailon T, McIntosh G, et al. Clinical outcomes research in spine surgery: what are appropriate follow-up times?. J Neurosurg Spine. 2018;30(3):397404.

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