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 Table of Contents  
RESEARCH ARTICLE
Year : 2018  |  Volume : 3  |  Issue : 2  |  Page : 45-51

Percutaneous transforaminal endoscopic discectomy for treatment of degenerative lumbar disc herniation in older adult patients: study protocol for a randomized controlled trial and preliminary results


Department of Spine Surgery, Dalian Municipal Central Hospital Affiliated to Dalian Medical University, Dalian, Liaoning Province, China

Date of Web Publication6-Jul-2018

Correspondence Address:
Li-Chen Xu
Department of Spine Surgery, Dalian Municipal Central Hospital Affiliated to Dalian Medical University, Dalian, Liaoning Province
China
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2542-3975.235147

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  Abstract 

Background and objectives: Percutaneous transforaminal endoscopic discectomy (PTED) is a major minimally invasive surgical method for the treatment of degenerative lumbar disc herniation. The choice of posture for patients undergoing PTED is controversial. Surgeons tend to perform PTED with the patient in the prone position rather than in the lateral position. Little is documented on which posture has higher efficacy and safety. This study will be performed to investigate the efficacy and safety of the prone position versus lateral position for older adult patients undergoing PTED for the treatment of degenerative lumbar disc herniation.
Design: A prospective, single-center, open-label, randomized controlled trial.
Methods: This study will include 168 older adult patients with degenerative lumbar intervertebral disc herniation who receive treatment in the Department of Spine Surgery, Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China. These patients will be randomized to undergo PTED in either the prone or lateral position (n = 84 patients in each surgical position). After surgery, all patients will be followed up for 2, 6, and 12 months.
Outcome measures and preliminary results: The primary outcome is the Oswestry Disability Index at 12 months postoperatively. This index is used to evaluate the improvement in low back pain. The secondary outcomes are the Oswestry Disability Index preoperatively (at baseline) and at 2 and 6 months postoperatively; X-ray morphology of the lumbar spine, Visual Analog Scale score, and Japanese Orthopaedic Association score preoperatively and at 2, 6, and 12 months postoperatively; modified MacNab grade at 2, 6, and 12 months postoperatively; partial pressures of oxygen and carbon dioxide preoperatively, intraoperatively, and 1 hour postoperatively; mean arterial pressure, Likert score, and times and doses of vasopressor used intraoperatively; and the incidence of recurrent lumbar intervertebral disc herniation and incidence of adverse reactions 12 months postoperatively. The results of 54 patients included in a pilot study of PTED showed that regardless of use of the prone position (n = 24) or lateral position (n = 28), the Visual Analog Scale score and Oswestry Disability Index at 2 months postoperatively were significantly lower than those before surgery (P < 0.05). Intraoperative arterial blood gas analysis revealed that the partial pressures of oxygen and carbon dioxide were significantly different between patients in the prone and lateral positions (P < 0.05).
Discussion: Based on the pilot study, future studies involving larger sample sizes are needed to investigate the short- and medium-term efficacy and safety of the prone versus lateral position for patients undergoing PTED for degenerative lumbar intervertebral disc herniation and to identify a better surgical posture suitable for older adult patients.
Ethics and dissemination: This study was approved by Medical Ethics Committee of Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China in May 2018 (approval No. 2018-012-01). This study protocol will be performed in strict accordance with the Declaration of Helsinki. Written informed consent will be obtained from the participants. The study protocol was designed in December 2017. Patient recruitment will begin in August 2018 and end in August 2019. Data analysis will begin in October 2020 and end in November 2020. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal.
Trial registration: This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800016399). Protocol version: 1.0.

Keywords: degenerative lumbar disc herniation; prone position; lateral position; percutaneous transforaminal endoscopic discectomy; older adult; Oswestry Disability Index; pain; adverse reaction


How to cite this article:
Xu LC, Xu WB, Yang DF, Zhang HB. Percutaneous transforaminal endoscopic discectomy for treatment of degenerative lumbar disc herniation in older adult patients: study protocol for a randomized controlled trial and preliminary results. Clin Trials Degener Dis 2018;3:45-51

How to cite this URL:
Xu LC, Xu WB, Yang DF, Zhang HB. Percutaneous transforaminal endoscopic discectomy for treatment of degenerative lumbar disc herniation in older adult patients: study protocol for a randomized controlled trial and preliminary results. Clin Trials Degener Dis [serial online] 2018 [cited 2018 Oct 21];3:45-51. Available from: http://www.clinicaltdd.com/text.asp?2018/3/2/45/235147


  Introduction Top


Research background

Lumbar disc herniation (LDH) is typically characterized by lower limb pain that radiates to the toes and is likely accompanied by unilateral paraspinal muscle spasm, limited lumbar flexion, hypoesthesia, muscle atrophy, and reflex change. Surgery is necessary in some patients with LDH.[1],[2],[3],[4] The available treatment methods for LDH include conservative treatment, interventional pain treatment, and surgery. Lumbar discectomy is the most common surgical treatment.[4],[5],[6]

Minimally invasive surgery, particularly percutaneous transforaminal endoscopic discectomy (PTED), has been more frequently used to treat LDH in recent years. Some retrospective studies have revealed that PTED for LDH exhibits encouraging efficacy and safety [Table 1].[7],[8],[9] Little information is available from prospective, large-sample randomized controlled trials. The optimal surgical posture for patients undergoing PTED is controversial.[10],[11] Most surgeons tend to select the prone position, but some prefer the lateral position. Few studies have revealed whether the prone position or lateral position is more suitable for older adult patients or described the advantages and shortcomings of these two surgical postures.
Table 1: Three retrospective clinical trials on percutaneous transforaminal endoscopic discectomy for the treatment of lumbar disc herniation published between 2016 and 2017

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Novelty of this study

The advantages of PTED over conventional surgery include a shorter surgical duration, less intraoperative blood loss, milder postoperative pain, and shorter hospitalization. The present study will involve preoperative and intraoperative blood gas analysis, intraoperative monitoring of the mean arterial pressure, assessment of the times and doses of vasopressor agents, and investigation of the effects of the lateral versus prone position on the circulatory and respiratory systems of patients undergoing PTED. These data are very important for LDH treatment in older adult patients.

Study objective

This prospective, single-center, open-label, randomized controlled trial will investigate the efficacy and safety of the prone versus lateral position in older adult patients undergoing PTED for the treatment of degenerative LDH.


  Methods/Design Top


Study design

A prospective, single-center, open-label, randomized controlled trial.

Study setting

Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China.



Recruitment

Recruitment will be performed using leaflets to advertise the study among patients in the clinics and wards at the Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China. The leaflets will provide detailed information regarding the trial. After being informed of the trial and its related interventions, patients interested in participation or their close relatives will complete the necessary paperwork, and confirmed participants will undergo follow-up examinations (routine blood tests, routine urine tests, liver and kidney function tests, blood gas analysis, and X-rays) without charge and will acquire compensation for transportation expenses.

Eligibility criteria

This study will recruit 168 older adult patients with degenerative LDH from the clinics and wards of the Department of Spine Surgery, Dalian Municipal Central Hospital Affiliated to Dalian Medical University according to the eligibility criteria.

Inclusion criteria

Patients presenting with all of the following criteria will be considered for inclusion:

  • Patients with initially diagnosed LDH undergoing initial surgery
  • Age of 60 to 75 years
  • Lower back pain or radiating pain in the lower limbs and positive physical signs consistent with imaging data
  • Either no improvement or aggravation of symptoms after 3 months of nonsurgical treatment
  • Provision of written informed consent


Exclusion criteria

  • A history of severe circulatory or respiratory system diseases
  • No obvious abnormality on electrocardiogram and lung function tests
  • Cardiac ejection fraction of ≤ 60%
  • Clinical manifestation of lumbar spondylolisthesis and lumbar instability
  • Spinal cord injury or nerve injury


Group allocation and blinding criteria

A random digital table will be generated using SPSS 19.0 software (IBM, Armonk, NY, USA). Each included patient will be assigned a random number from 1 to 168. Patients with an odd number will be assigned to the prone position PTED group (n = 84), and those with an even number will be assigned to the lateral position PTED group (n = 84). Allocation concealment and blinding will not be used.

Interventions

According to a previous study,[10] all surgeries will be performed under monitored anesthesia. Conventional oxygen therapy (4 L/min) via a mask will be used. Lidocaine (1%) will be used for local infiltration anesthesia, and dexmedetomidine (0.4 μg/kg/h) will be administered through an intravenous infusion pump. During the surgery, local anesthetics will be used according to the patient’s reaction. Vasoactive drugs will be used when necessary to maintain the mean arterial pressure at 60 to 80 mmHg.

The standard Tessys method will be used to remove the herniated discs [Figure 1]. The patients will be asked to lie in either the prone or lateral position. After routine preoperative preparation, lumbar puncture will be performed under a C-arm X-ray device. After insertion of a guide wire, the puncture pin will be withdrawn. A 0.8-cm-long incision will be made at the puncture site. With the aid of the C-arm X-ray device, the insertion position of the sleeve will be determined, and an expansion sleeve will be inserted to establish a surgical channel. Physiological saline will be continuously infused. After identification of the anatomical structure of the operative field, the nucleus pulposus and other tissues in the broken disc will be removed using the transforaminal approach. After the nerve root has been fully decompressed, the working sleeve will be pulled out and the skin will be sutured.
Figure 1: Schematic diagram of removal of nucleus pulposus of a herniated disc using Tessys method under a C-arm X-ray device.

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Outcome measures

Primary outcome measure

- Oswestry Disability Index at 12 months postoperatively. This index is used to evaluate the improvement in low back pain. The Oswestry Disability Index questionnaire evaluates the patient’s ability in 10 aspects including pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sex life, social life, and travelling. The maximum score for each aspect is 5 points. A higher score indicates more severe dysfunction.[12]

Secondary outcome measures

- Oswestry Disability Index at baseline (preoperatively) and at 2 and 6 months postoperatively. The scoring method is the same as that described above.

- X-ray morphology of the lumbar spine at baseline and at 2, 6, and 12 months postoperatively. The morphology of the lumbar spine will be displayed on X-rays to observe the recovery of the degenerative intervertebral disc.

- Modified MacNab grade at 2, 6, and 12 months postoperatively. A grade of excellent indicates that the patient is free of pain, has no restriction of mobility, and is able to return to normal work and activities. A grade of good indicates that the patient has occasional non-radiating pain, has slightly restricted mobility, and is able to return to normal work and activities. A grade of fair indicates relief of pain symptoms, restricted mobility, and a handicapped and/or unemployed status. Finally, a grade of poor indicates no difference between before and after treatments and even aggravation of pain symptoms.[13] The following formula will be used: Excellent and good rate of recovery of modified MacNab criteria = (number of patients with excellent and good recovery) / total number of patients included × 100%. A higher value indicates better recovery.

- Visual Analog Scale score at baseline and at 2, 6, and 12 months postoperatively. The visual analog scale score[14] ranges from 0 to 10. A higher score represents more severe pain.

- Japanese Orthopedic Association (JOA) score at baseline and at 2, 6, and 12 months postoperatively. The total JOA score[15] ranges from 0 to 29. A lower JOA score indicates more severe lumbar dysfunction. The following formulas will be used: Improvement index = JOA score after treatment − JOA score before treatment. Improvement rate = [(JOA score after treatment − JOA score before treatment) / 29 − JOA score before treatment] × 100%. The improvement index reflects the improvement in lumbar spine function after treatment.

- Partial pressures of oxygen and carbon dioxide preoperatively, intraoperatively, and at 1 hour postoperatively. The partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) will be measured for blood gas analysis before surgery (after posture fixation and before routine disinfection), during surgery, and 1 hour after surgery.

- Intraoperative mean arterial pressure. The mean arterial pressure will be measured during the surgery. The normal adult blood pressure is 70 to 105 mmHg (1 mmHg = 0.133 kPa). The following formula will be used: Mean arterial pressure = [systolic pressure + (2 × diastolic pressure)] / 3.

- Intraoperative Likert score. A 5-point Likert score scale (1, very strong; 5, very weak) will be used.[10]

- Intraoperative times and doses of vasopressor drugs used. During the surgery, vasopressor drugs will be used based on the decrease in blood pressure, and the times and doses of vasopressor drugs will be recorded.

- Incidence of recurrent LDH at 12 months postoperatively. The following formula will be used: Incidence of recurrent LDH = number of patients with recurrent LDH / total number of patients × 100%. Higher values indicate poor efficacy.

- Incidence of adverse reactions at 12 months postoperatively. Adverse reactions during the follow-up period will be recorded, including fecal and urinary incontinence, lower limb paralysis, iatrogenic lumbar stenosis, residual nucleus pulposus, lateral crypt stenosis, lumbar segmental instability, nerve root injury, and interstitial tissue infection. The following formula will be used: Incidence of adverse reactions = number of patients with adverse reactions / total number of patients × 100%.

The schedule for outcome measure assessments is shown in [Table 2].
Table 2: Schedule for outcome measure assessment

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Adverse events

The adverse reactions occurring during the follow-up period will be recorded. The first onset time, severity, and management of adverse events will be recorded and reported to the project manager and the study’s ethics committee within 24 hours.

Trial procedure

168 older adult patients with degenerative LDH will be recruited in this study from the clinics and wards of the Department of Spine Surgery, Dalian Municipal Central Hospital Affiliated to Dalian Medical University and randomized to receive prone-position PTED and lateral-position PTED, with 84 patients in each group [Figure 2].
Figure 2: Flow chart of trial.
Note: LDH: Lumbar disc herniation; PTED: percutaneous transforaminal endoscopic discectomy.


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Sample size

In accordance with our preliminary results and clinical experience,[10] we hypothesized that preoperative Oswestry Disability Index in patients with older adult patients with degenerative LDH was 40 ± 9, and Oswestry Disability Index at 12 months post-surgery was decreased by 30 in the lateral-position PTED group and decreased by 25 in the prone-position PTED group, with the standard deviation of 9. Assuming β = 0.1, power = 90%, α = 0.05 (two-sided), a final sample size of n = 70 per group was calculated using the PASS 11.0 software (PASS, Kaysville, UT, USA). Assuming a participant loss rate of 20%, we will require a sample size of n = 84 per group. Therefore, a total sample size of 168 will be used in this study.

Statistical analysis

Data description

All data will be statistically processed using the SPSS 20.0 software (IBM, Armonk, NY, USA) following the intention-to-treat principle. Normally distributed measurement data will be expressed as means and standard deviations. Non-normally distributed data will be expressed as lower quartiles (q1), medians, and upper quartiles (q3). Count data will be expressed as percentage.

Selection of statistical methods

Repeated measures analysis of variance will be used to compare the Oswestry Disability Index, Visual Analog Scale score, and Japanese Orthopedic Association score at different time points between prone-position PTED and lateral-position PTED groups. Least Significant Difference test will be used for pairwise comparisons. Two sample t-test (for normally distributed data) or Mann-Whitney U test (non-normally distributed data) will be used to compare partial pressure of oxygen, partial pressure of carbon dioxide, mean arterial pressure, Likert score, and times and doses of vasopressor drugs used. Pearson chi-square test will be used for comparisons of incidence of recurrent lumbar disc herniation and incidence of adverse reactions.

Data sets

The patients included in the final analysis are mainly the population assigned to the per protocol set. Per protocol set refers to the set of subjects who meet inclusion and exclusion criteria, complete the study without major protocol deviations, provide effective baseline efficacy and tight enough compliance, and fulfill the case report form.

Data collection and management

Data collection

Case report forms will be filled by the investigators accurately, completely, and on time. Written records will be transferred to an electronic format by professional staff using a double data entry strategy.

Data management

Research data will be statistically analyzed and reported by professional statisticians. A final report will be made by principle investigators. The database will be locked and any non-authorized researcher will have no right to inquire about the database. All data relating to this study will be preserved by Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China.

Monitoring

Independent Data Monitoring Committee composition

The role and responsibilities of the Independent Data Monitoring Committee relative to the investigators and ethics committee will be identified. The role and responsibilities of the Independent Data Monitoring Committee will be relative to the project steering committee, clinical pharmacologists and/or toxicologists, epidemiologists, statisticians, clinical trial managers, and ethics experts.

Investigator qualification

All surgeons participating in this study have a wealth of experience in similar operations and can skillfully perform surgical procedures. The surgeries will be performed by senior orthopedic surgeons. Physicians responsible for Oswestry Disability Index and JOA scoring and imaging evaluation should have underwent professional training and have abundant experience in this research field.

Auditing

The monitors will visit the trial institute regularly or according to the actual situation to carry out clinical quality audit work. They will report the progress of the trial to the ethics committee every 3 months and update the trial progress in the registration database.

Compensation to patients

Patients included in the clinical trial can inquire the latest treatment-related information and will be followed up closely by professional medical teams in the research unit without charge. They can be also compensated in follow-up-related examination and registration fees.

Ethics and dissemination

This study was approved by Medical Ethics Committee, Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China (approval No. 2018-012-01).

The trial was reported in line with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklist[16] (Additional file 1 [Additional file 1]).

This study protocol will be performed in strict accordance with the Declaration of Helsinki. Written informed consent will be obtained from each patient. When the investigators discover that there are risks beyond expectations in the clinical trials, they will modify the contents of the informed consent together with the sponsors. After the approval of relevant working procedures has been achieved from the ethics committee, the affected patients or their guardians will re-sign the modified informed consent forms. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal. Anonymized trial data will be published at www.figshare.com.


  Preliminary Results Top


Fifty-four older adult patients with degenerative LDH who underwent prone position PETD (n = 24) or lateral position PETD (n = 28) from August 2015 to October 2016 were included in the pilot study.

The effects of PETD performed in different postures on the respiratory and circulatory systems in patients with degenerative LDH are shown in [Table 3].
Table 3: Effects of different postures for PTED on respiratory and circulatory systems

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There were no significant differences in PaO2 or PaCO2 between patients in the prone position PETD and lateral position PETD groups. After 1 hour of surgery, blood gas analysis revealed that the PaO2, PaCO2 (both P < 0.01), and mean arterial pressure (P < 0.05) were significantly different between these two groups. There was no significant difference in the number of times a vasopressor agent (norepinephrine) was used between the two groups, but the total amount of vasopressor agent used was significantly different between the two groups (P < 0.05). These results suggest that lateral position PETD influences the respiratory and circulatory systems of older adult patients less than prone position PETD.

The Visual Analog Scale score and Oswestry Disability Index were significantly lower at 2 months postoperatively than before surgery in each group (P < 0.05; [Table 4]). There were no significant differences in the operation time or postoperative function recovery between the prone position PETD and lateral position PETD groups.
Table 4: VAS score and ODI in patients undergoing PTED at different postures before and after surgery

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No adverse reactions such as intervertebral space infection, nerve root injury, dural tear, or abdominal organ or vascular injury occurred in either group.

Preliminary results revealed that lateral position PETD showed better efficacy at 2 months postoperatively than prone position PETD and that it had less influences on the respiratory and circulatory systems in older adult patients.


  Discussion Top


Previous contributions and existing problems

Small-incision minimally invasive discectomy remains the gold standard for LDH.[17] Increasingly more spine surgeons are beginning to apply PETD because it has several advantages over conventional incision surgery, including a shorter operation time, less intraoperative bleeding, milder postoperative pain, and shorter hospitalization. In addition, PETD under local anesthesia can greatly reduce the potential risk of nerve root injury. Therefore, PETD is of important practical significance. Few studies have revealed the effects of different postures on the efficacy of PETD. Chu et al.[11] reported that there was no significant difference in the efficacy of PETD between the prone and lateral positions and that significantly fewer patients felt extremely uncomfortable in the lateral than prone position. Little is documented on the effects of different postures for PETD on respiratory indices in the blood gas analysis in patients with LDH.

Features of this study

Few prospective randomized controlled trials have been performed to assess the long-term efficacy and safety of PETD in the treatment of LDH. This prospective, single-center, open-label randomized controlled trial will investigate the efficacy and safety of prone position PETD versus lateral position PETD in the treatment of older adult patients with LDH.

Limitations of this study

The study will include only Chinese patients, perhaps limiting the generalizability of its results somewhat. PETD is an effective surgical method for treating patients with persistent symptoms of LDH. However, more clinical studies are required to investigate its efficacy and safety beyond 1 year postoperatively. Allocation concealment and blinding will not be used in the randomization of this study. This may influence the accuracy of the results.

Significance of this study

This study will be performed to investigate whether prone position PETD or lateral position PETD exhibits greater efficacy and safety in the treatment of older adult patients with LDH and the advantages and disadvantages of each posture.


  Trial Status Top


Protocol design has been just completed at the time of submission. The results from a pilot study have been reported. 10 Patient recruitment will begin in July 2018.

Additional file

Additional file 1: SPIRIT checklist.

Author contributions

Conception and design of this study: LCX; patient recruitment: WBX; data collection and analysis: DFY and HBZ. All authors approved the final version of this manuscript for publication.

Conflicts of interest

There are no conflicts of interest.

Financial support

None.

Institutional review board statement

This study protocol will be performed in strict accordance with the Declaration of Helsinki. This study was approved by Medical Ethics Committee, Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China (approval No. 2018-012-01). Surgeons participating in this trial should have met the qualification requirements for ultrasound and magnetic resonance imaging examination.

Declaration of patient consent

The authors certify that they will obtain patient consent forms. In the form, patients will give their consent for their images and other clinical information to be reported in the journal. The patients will understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Reporting statement

This study follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklist.

Biostatistics statement

The statistical methods of this study were reviewed by the biostatisticians of Dalian Municipal Central Hospital Affiliated to Dalian Medical University, China.

Copyright transfer agreement

The Copyright License Agreement has been signed by all authors before publication.

Data sharing statement

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices) will be available. Study protocol and informed consent will be available immediately after publication. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal. Anonymized trial data will be available indefinitely at http://www.clinicaltdd.com.

Plagiarism check

Checked twice by iThenticate.

Peer review

Externally peer reviewed.

 
  References Top

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Huschak G, Holzhausen HJ, Beier A, Meisel HJ, Hoell T. Lack of relationship between occupational workload and microscopic alterations in lumbar intervertebral disc disease. Open Orthop J. 2014;8:242-249.  Back to cited text no. 3
    
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    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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