Erratum. Percutaneous transforaminal endoscopic discectomy compared with microendoscopic discectomy for lumbar disc herniation: 1-year results of an ongoing randomized controlled trial

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TO THE READERSHIP: Some errors appeared in our recent article (Chen Z, Zhang L, Dong J, et al: Percutaneous transforaminal endoscopic discectomy compared with microendoscopic discectomy for lumbar disc herniation: 1-year results of an ongoing randomized controlled trial. J Neurosurg Spine 28:300–310, 2018).

To compare the quality of life between groups via the EuroQol Group’s EQ-5D system, utility values should be used. These values can be obtained by converting raw data using the time-trade-off method. Previously, we did not comprehend this complicated calculation well, and thus we included incorrect results for the EQ-5D values in our published article. We now take the opportunity to correct our errors. All corrections are marked in bold typeface.

Page 303, Table 1: the preoperative EQ-5D scores were initially shown as 0.42 ± 0.04 in the percutaneous transforaminal endoscopic discectomy (PTED) group and 0.44 ± 0.04 in the microendoscopic discectomy (MED) group, with a p value of 0.683. The corrected data are EQ-5D scores of 0.53 ± 0.25 in the PTED group and 0.52 ± 0.25 in the MED group, with a p value of 0.819.

TABLE 1.

Baseline clinical characteristics and demographic data of 153 patients

VariablePTEDMEDp Value
No. of patients8073
Age, yrs40.2 ± 11.440.7 ± 11.10.589
Male sex52 (65.0)37 (50.7)0.073
BMI, kg/m223.4 ± 2.923.6 ± 3.60.704
Heavy labor17 (21.3)11 (15.1)0.323
Sedentariness*16 (20.0)11 (15.1)0.424
Smoking history21 (26.3)18 (24.7)0.821
Positive nerve root tension test60 (75.0)51 (69.9)0.477
Decreased sensation26 (32.5)28 (38.4)0.449
Myotomal weakness25 (31.3)16 (21.9)0.193
Depressed reflex23 (28.7)26 (35.6)0.363
Type of disc herniation0.149
 Median15 (18.8)19 (26.0)
 Paramedian56 (70.0)48 (65.8)
 Far lateral9 (11.3)6 (8.2)
Surgical segment0.504
 L3–4 or higher4 (5.0)0
 L4–535 (43.8)35 (47.9)
 L5–S141 (51.2)38 (52.1)
ODI score43.1 ± 21.044.9 ± 21.20.734
SF36-PF score52.3 ± 25.352.4 ± 26.80.322
SF36-BP score47.4 ± 18.846.9 ± 21.20.411
EQ-5D score0.53 ± 0.250.52 ± 0.250.819
VAS-BP score3.7 ± 2.73.9 ± 2.50.547
VAS-LP score5.6 ± 1.95.3 ± 2.20.224
BMI = body mass index.Values expressed as the mean ± SD or number (%) of patients.

Sedentariness defined as sitting > 8 hours per day.

Page 303, Table 2: All values related to the EQ-5D score have been corrected. All corrections are marked in bold typeface in the table shown on the following page.

TABLE 2.

Primary and secondary outcomes of treatment with PTED versus MED

VariablePTEDMEDp Value
ODI score
 Baseline44.2 ± 21.843.8 ± 20.40.908
 1 wk29.7 ± 18.9*31.0 ± 18.8*0.673
 1 mo18.9 ± 17.9*19.6 ± 14.8*0.807
 3 mos11.3 ± 13.6*9.2 ± 9.1*0.302
 6 mos6.0 ± 8.4*5.1 ± 6.7*0.487
 1 yr3.9 ± 7.6*3.2 ± 5.7*0.533
SF36-PF score
 Baseline52.6 ± 25.552.12 ± 26.50.917
 1 wk63.5 ± 24.6*62.0 ± 26.6*0.726
 1 mo78.7 ± 21.9*81.5 ± 8.2*0.414
 3 mos89.5 ± 15.4*92.7 ± 8.2*0.138
 6 mos96.3 ± 4.6*96.2 ± 5.1*0.927
 1 yr97.2 ± 6.4*97.9 ± 3.6*0.488
SF36-BP score
 Baseline45.5 ± 19.049.0 ± 20.80.280
 1 wk67.5 ± 21.1*66.1 ± 19.7*0.666
 1 mo78.5 ± 18.2*80.5 ±1 5.9*0.486
 3 mos86.6 ± 16.8*87.6 ± 14.1*0.720
 6 mos90.4 ± 17.0*91.6 ± 9.6*0.595
 1 yr91.0 ± 21.6*95.6 ± 6.7*0.156
EQ-5D score
 Baseline0.53 ± 0.250.52 ± 0.250.819
 1 wk0.74 ± 0.22*0.69 ± 0.23*0.166
 1 mo0.82 ± 0.23*0.83 ± 0.17*0.767
 3 mos0.91 ± 0.16*0.91 ± 0.12*0.851
 6 mos0.94 ± 0.12*0.95 ± 0.08*0.631
 1 yr0.96 ± 0.11*0.97 ± 0.07*0.562
VAS-BP score
 Baseline3.9 ± 2.63.7 ± 2.60.683
 1 wk1.4 ± 1.8*1.6 ± 1.8*0.488
 1 mo1.1 ± 1.5*1.1 ± 1.6*0.859
 3 mos0.9 ± 1.5*0.8 ± 1.3*0.617
 6 mos0.6 ± 1.2*0.5 ± 0.8*0.589
 1 yr0.5 ± 1.3*0.4 ± 0.8*0.483
VAS-LP score
 Baseline5.5 ± 1.95.5 ± 2.20.862
 At 1 wk1.8 ± 2.3*2.1 ± 2.2*0.555
 1 mo1.5 ± 1.9*1.3 ± 1.7*0.497
 3 mos1.1 ± 1.5*1.0 ± 1.7*0.962
 6 mos0.6 ± 1.3*0.6 ± 1.2*0.919
 1 yr0.6 ± 1.4*0.4 ± 1.0*0.525
Values expressed as the mean ± SD.

Significantly different than baseline data.

Page 304, Outcome Assessment, paragraph 2: We originally stated, “EQ-5D (ranging from 0 to 1, with a higher score indicating better quality of life).” The corrected phrase now reads “EQ-5D (ranging from −0.149 to 1, with a higher score indicating better quality of life).”

Page 305, Fig. 3: In accordance with the corrected EQ-5D scores shown in Table 2, we have also corrected panel E (EQ-5D) in Fig. 3 (see correction on the following page).

FIG. 3.
FIG. 3.

Scores on secondary outcome measures of SF36-PF (A), SF36-BP (B), VAS-back (C), VAS-leg (D), and EQ-5D (E). The graphs show that there was no significant difference between treatment groups in any of the secondary outcomes at each follow-up point. The differences in all secondary outcomes between baseline and each follow-up point were statistically significant in both treatment groups. Figure is available in color online only.

It should be noted that our corrections do not change the results or conclusions of our study. We apologize for making these errors and appreciate the opportunity to correct them at this time.

The article has been corrected online as of July 26, 2019.

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Article Information

Contributor Notes

INCLUDE WHEN CITING Published online July 26, 2019; DOI: 10.3171/2019.5.SPINE161434a.
Figures
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    Scores on secondary outcome measures of SF36-PF (A), SF36-BP (B), VAS-back (C), VAS-leg (D), and EQ-5D (E). The graphs show that there was no significant difference between treatment groups in any of the secondary outcomes at each follow-up point. The differences in all secondary outcomes between baseline and each follow-up point were statistically significant in both treatment groups. Figure is available in color online only.

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