Macquarie Neurosurgery Journal Club 2022 PPT

1. MACQUARIE NEUROSURGERY
JOURNAL CLUB
Gadjradj PS, Rubinstein SM, Peul WC, Depauw PR, Vleggeert-Lankamp CL, Seiger A, van Susante
JL, de Boer MR, van Tulder MW, Harhangi BS. Full endoscopic versus open discectomy for sciatica:
randomised controlled non-inferiority trial. BMJ. 2022 Feb 21;376:e065846.
Miracle C. Anokwute, MD
03/03/2022

2. Is the study question relevant?
Why was the study done?
-Recent increase in use of endoscopic spine surgery for degenerative spine disease
-Despite good outcomes in other countries, insurance companies in Netherlands won’t
reimburse for the procedure
-Determine if percutaneous transforaminal endoscopic discectomy is non-inferior to open
microdiscectomy for reduction of leg pain
-To obtain insurance reimbursements for endoscopic spine surgery
Originality of the work?
-Not original. Multiple randomized control trials for endoscopic lumbar discectomy
-Original for Netherlands
Did the study add anything new?
- Yes for the Netherlands population. No for the rest of the world
Where was the study published?
• BMJ: high Journal Impact Factor 39.89
• Article has been cited by 47 other papers since it was published in 2022 (Scopus)
• Other metrics
• Author h-index: van Tulder MW: 103, Corresponding author Harhangi: 20; Rubinstein: 34;
Peul: 56;

3. Research hypothesis
What was the research hypothesis? Was it explicitly stated?
-Percutaneous Transforaminal Endoscopic Discectomy (PTED) is non-inferior to open microlumbar
discectomy (MLD) for leg pain reduction.
Did the study follow a protocol? Was the protocol followed throughout?
-The protocol was published in 2017 and followed throughout.
- Seiger A, Gadjradj PS, Harhangi BS, et al PTED study: design of a non-inferiority, randomised
controlled trial to compare the effectiveness and cost-effectiveness of percutaneous transforaminal
endoscopic discectomy (PTED) versus open microdiscectomy for patients with a symptomatic
lumbar disc herniationBMJ Open 2017;7:e018230. doi: 10.1136/bmjopen-2017-018230
- Protocol was amended after enrollment started but before study completion
-Included 11 point numerical rating scale for outcome measured by VAS (concern about validity
of VAS on different devices i.e cell phone vs tablet vs computer) and added this as the primary
outcome
- reinstated the VAS as primary outcome when realized it should be similar to numerical rating
scale
-Increased enrollment period to 3 years (initially planned a 2 year period)
-Follow up increased to 24 months and 60months

4. Study design
• What type of research question was being asked?
-Intervention
• What was the study design?
-Non-inferiority non-blinded randomized control trial (A trial performed if unable
to identify a placebo)
• Is there an appropriate Critical Appraisal checklist that can be used? Yes
See link to Critical Appraisal resources: Duke University Guide:
https://libguides.mq.edu.au/c.php?g=674377&p=4748716
• Duration of Follow-up
-1 day; 2, 4, and 6 weeks; 3, 6, 9, 12 months
• Outcome Assessment
-Primary Outcome: Visual Analog Scale (VAS) for leg pain at 1 year
-Secondary Outcome: Functional outcome with ODI (0-100), VAS for back pain
(0-100), VAS for quality of life (0-100), SF 36 for physical component and mental
component summary, 7 point Likert-type scales for self perceived recovery from
symptoms recovery from leg pain, satisfaction with treatment, and change in
symptoms at 1 year.

5. Internal Validity (Sources of Bias)
Trial design
-Enrolled from 2016-2019 in Netherlands
-4 hospital sites, 1 clinic
-Neurosurgeons and Orthopedic spine surgeons
-Sources of selection bias: reimbursement for PTED was tied to
trial
-No differences in baseline characteristics of 2 groups.
-Difference in intervention as PTED surgeons needed to be trained
(125 learning curve cases included in randomization). Only 179 PTED
cases included in analysis
Sample size / power calculations
-Needed 306 participants per group with goal of 682 participants for
noninferiority with power of 90%
-recruited 711 but randomized 613
- Appropriately sized. 613 participants (304 PTED, 309 open MLD)
Randomization
- Computer block generated (1:1 randomization)
Blinding
-Non-blinded

6. Internal Validity (Sources of Bias)
Statistical analysis – were appropriate statistical tests used?
-analyzed the expected mean difference between groups for VAS
-Primary Analysis: Intention to treat principle
-Protocol analysis: sensitivity analyses
-sensitivity analyses for learning curve group and numerical rating scale to test
validity of results
-baseline characteristics as categorical variables with percentages and as continuous
variables with Means and SD or medians and Interquartile ranges
-mixed-model analyses: random intercepts on patient level to account for dependency
of measurements over time within patients
-linear mixed models: analyze leg pain, functional disability, back pain, QOL, physical
component summary, and mental component summary
-logistic mixed models: analyze dichotomized Likert-type scales
-Fully adjusted models: adjustment for factors like baseline score, center, age, sex,
duration of complaints, smoking status, BMI, employment status, sit of disc
protrusion, treatment preference of patient, and psychopathology.
-linear and logistic regression analysis: adjusted for baseline and hospital for
outcomes at 12months

7. External validity (generalisability)
Inclusion:
- Aged 18–70 years
-More than 10 weeks of radiating pain with or without motor or sensory loss in the leg, or with >6 weeks of
excessive radiating pain and no tendency for any clinical improvement
-Indication for surgery
-MRI demonstrating a lumbar disc herniation with nerve compression with or without concomitant spinal or
lateral recess stenosis or sequestration
-Sufficient knowledge of the Dutch language in order to complete forms and follow instructions independently.
Exclusion criteria
-Previous surgery on the same or adjacent disc level
-Cauda equina syndrome
-Spondylytic or degenerative spondylolisthesis
-Pregnancy
-Severe comorbid medical or psychiatric disorder (American Society of Anesthesiologists >2)
-Severe caudal or cranial sequestration
-Contraindication for surgery
-Moving abroad at short notice
Can the results be applied to my patient? Yes and No (If you perform open microlumbar discectomies then
yes; if you perform minimally invasive tubular discectomies then no)

8. 8
Fig 1: Participant Flow
Chart
Results

9. Results
9
Primary outcomes
- Median VAS Leg pain
scores were similar for 3
months then favored
PTED from months 6-
12months
- Mean between group
difference was 7.1 at
12months for PTED
-demonstrates PTED is
non-inferior (between
group difference is not
<5.0)

10. Results
10
Secondary outcomes
- Mean difference in median score for ODI (5.3, 3.0, and 7.7) at months 6, 9, and 12 in favor
of PTED
- Mean difference in Interquartile range for back pain (6.0, 2.0, and 10.0) at months 6, 9, and
12 in favor of PTED
- Mean difference in Median VAS for quality of life was (-6.2, -9.2, and -3.2) at 6, 9, and
12months in favor of PTED
- Mean difference in SF 36 physical component and mental component summary at
12months -2.8 and -2.1 respectively in favor of PTED.
- OR of recovery of symptoms was 2.7 and OR for recovery of leg pain was 2.0 in favor of
PTED at 12months
- OR for satisfaction with change in symptoms was 2.6 and satisfaction with result of
treatment was 2.6 in favor of PTED

11. Results
11
Adverse events
-less blood loss w/ PTED
-8 dural tears (3%) and 3(1%) wound infections
in open MLD
-1 (0.4%) nerve root injury and 1 (0.4%) DVT in
open MLD
-94% of PTED could be discharged at same day;
6% with open MLD
-scar length (OBVIOUSLY longer in open MLD)
-revision surgery at 1yr (5.3% PTED vs 5.6%
open MLD)
-similar use of non-opioid analgesics

12. Results
12
Statistical analysis (estimate of effect size and precision)
Alternative, per protocol, and sensitivity analyses conducted :
Figure 3. Results of primary outcome for main and alternative
analyses

13. Results
13
Have allowances been made for multiple comparisons?
Alternative statistical analyses:
- Linear logistical regression analyses for leg pain
- Intention-to-treat analysis for secondary outcomes
- Sensitivity analyses for included learning curve patients
- Performed analyses using numerical rating scale instead of VAS for leg
pain back pain, and QOL
- Results were similar to primary analyses. Therefore, the results are valid
for non-inferiority.

14. Discussion / conclusions
Were all clinically important outcomes considered?
Yes
Did the data justify the conclusions?
Yes
What were the study limitations?
- Participation bias (patients want PTED)
- non-blinded study
- Did not reach pre-estimated sample size of 682
- Does not evaluate minimally invasive tubular MLD
Are the likely treatment benefits worth the potential harms and costs?
Yes
Were there any conflicts of interest (declared or otherwise)?
-Yes: surgeons performing PTED were reimbursed for PTED (unsure if PTED has
higher reimbursement)

15. Presentation and style
Clarity of writing, economy of words, organization of paper
-Clear paper, well organized
Number & quality of figures, tables & illustrations
-Overall good
Relevance, accuracy and completeness of bibliography
-Overall good

16. Conclusion
Summary of key strengths and weaknesses (take away message)
-PTED is non-inferior to OPEN MLD
-PTED is not known to be superior to minimally invasive tubular MLD
Is the study believable (internally valid)?
-Yes
Is the study relevant?
-Yes
Will the study change my practice?
-No: the study does not compare minimally invasive tubular MLD to PTED