Total laminectomy combined with lumbar pedicle screw fixation for treatment of lower back and leg pain in older adult patients with degenerative lumbar spinal stenosis: study protocol for a self-control trial and preliminary results
Chun-liang Li1, Qiang Guo1, Feng Qin2, Wen-qi Yan1, Hai-yong Zhu1, Kai Wang1
1 Department of Orthopedics, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
2 Department of Endocrinology, Affiliated Hospital of Qinghai University, Xining, Qinghai Province, China
|Date of Web Publication||8-Mar-2018|
Department of Orthopedics, Qinghai Provincial People's Hospital, Xining, Qinghai Province
Source of Support: None, Conflict of Interest: None
Background and objectives: Senile degenerative lumbar spinal stenosis typically manifests clinically as lower back and leg pain caused by compression of the nerve root. Conventional total laminectomy for degenerative lumbar spinal stenosis can quickly alleviate a patient's symptoms, but produces an unsatisfactory therapeutic effect because of spinal instability caused by degenerative spondylolisthesis, and also has many adverse reactions. The purpose of this study is to investigate whether total laminectomy combined with lumbar pedicle screw fixation for treatment of senile degenerative lumbar spinal stenosis can effectively reduce lower back and leg pain caused by compression of the nerve root, increase lumbar spine stability, and reduce adverse reactions.
Design: A prospective, single-center, self-control, interventional trial.
Methods: One hundred and sixty older adult patients with degenerative lumbar spinal stenosis who will receive treatment at the Department of Orthopedics, Qinghai Provincial People's Hospital, China will be included in this study. All patients will undergo total laminectomy combined with lumbar pedicle screw fixation, with follow-up at 3, 6, 9, and 12 months post-surgery.
Outcome measures and preliminary results: The primary outcome measure of this study is recovery rate in Japanese Orthopedic Society (JOA) score at 12 months post-surgery, which is used to evaluate improvements in patients lower back and leg pain. Secondary outcome measures of this study include changes in JOA score, spinal canal diameter, lumbar spine morphology displayed on computed tomography images, and incidence of adverse events post-surgery. Results of a preliminary study involving 71 older adult patients with degenerative lumbar spinal stenosis who received the same treatment showed that at 3 months post-surgery, JOA score and spinal canal diameter were significantly increased compared with before surgery (P < 0.05).
Discussion: Findings from this study may provide clinical evidence supporting that total laminectomy combined with lumbar pedicle screw fixation is a safe and reliable method for treatment of senile degenerative lumbar spinal stenosis because it rapidly alleviates lower back and leg pain and provides spine stability.
Ethics and dissemination: This study was approved by Medical Ethics Committee of Qinghai Provincial People's Hospital of China (approval No. QHY201602G). This study will be performed in strict accordance with the Declaration of Helsinki formulated by the World Medical Association. Participants will provide signed informed consent prior to participation in the study. This study was designed in December 2017. Patient recruitment and data collection will begin in August 2018. Data analysis will be performed in October 2019. The study will be completed in December 2019. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal. Protocol version: 1.0.
Trial registration: This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800014726).
Keywords: lumbar spinal stenosis; older adults; lower back and leg pain; nerve root; Japanese Orthopedic Society score; spinal canal diameter; spine stability; CT examinatin; degenerative spondylolisthesis
|How to cite this article:|
Li Cl, Guo Q, Qin F, Yan Wq, Zhu Hy, Wang K. Total laminectomy combined with lumbar pedicle screw fixation for treatment of lower back and leg pain in older adult patients with degenerative lumbar spinal stenosis: study protocol for a self-control trial and preliminary results. Asia Pac J Clin Trials Nerv Syst Dis 2018;3:10-6
|How to cite this URL:|
Li Cl, Guo Q, Qin F, Yan Wq, Zhu Hy, Wang K. Total laminectomy combined with lumbar pedicle screw fixation for treatment of lower back and leg pain in older adult patients with degenerative lumbar spinal stenosis: study protocol for a self-control trial and preliminary results. Asia Pac J Clin Trials Nerv Syst Dis [serial online] 2018 [cited 2021 Jun 14];3:10-6. Available from: https://www.actnjournal.com/text.asp?2018/3/1/10/226193
| Introduction|| |
Senile degenerative lumbar spinal stenosis is a common disease that occurs in older adults because of age-related changes in tissue structure and morphology (Li et al., 2011; Na et al., 2011; Vasilenko et al., 2015). Conventional total laminectomy for senile degenerative lumbar spinal stenosis can quickly alleviate a patient's symptoms, but produces an unsatisfactory therapeutic effect (because of spinal instability caused by degenerative spondylolisthesis) and many adverse events (Hao et al., 2010; Ren and Zhang, 2010). In addition, postoperative formation of scar tissue likely stimulates the nerve root, ultimately resulting in lower back pain. Lumbar pedicle screw fixation for repair of injured lumbar spine can provide spine stability, shorten a patient's time in bed, and reduce the likelihood of postoperative paralysis (Bernard et al., 2017; Matsukawa et al., 2017; Seo et al., 2017; Wang et al., 2017; Ye et al., 2017). Previous randomized controlled trials addressing the therapeutic effects of lumbar spinal stenosis are shown in [Table 1] (Moojen et al., 2013; Moojen et al., 2015; Benyamin et al., 2016).
|Table 1: Randomized controlled trials (RCTs) regarding treatment of lumbar spinal stenosis|
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Novelty of this study
In this study, to achieve a desirable decompressive effect, total laminectomy will be performed to relieve pressure on spinal nerve roots at the bulging level of the dural sac. In addition, lumbar pedicle screw fixation will be performed to provide spine stability, shorten the patient's time in bed, and reduce the likelihood of lower back and leg pain, and paralysis.
In this study, total laminectomy combined with lumbar pedicle screw fixation will be used for treatment of senile degenerative lumbar spinal stenosis, to determine whether this combined therapy can alleviate lower back and leg pain and provide spine stability with minimal adverse reactions.
| Methods/Design|| |
A prospective, single-center, self-control, interventional trial.
Department of Orthopedics, Qinghai Provincial People's Hospital, China.
Recruitment will be performed using a leaflet to advertise for patients from clinics and wards of Qinghai Provincial People's Hospital, China, and their relatives. Patients participating in this study will receive appointments from a panel of well-known hospital experts without having to pay for examination fees, and will also receive a transportation allowance. After being made aware of the objective of the trial and its related interventions, patients interested in participation can contact the project manager by providing appropriate information (e.g., name and telephone number). Potential patients will be preliminarily screened according to inclusion and exclusion criteria. Eligible patients will volunteer to participate in the study. Only those providing informed consent will be considered for inclusion. The personal information of included patients will be kept strictly confidential.
Participants meeting all the following conditions will be considered for inclusion:
- Presenting with symptoms corresponding to the diagnostic criteria of lumbar spinal stenosis (Liu et al., 2004): (1) history of chronic lower back pain and trauma (in some patients); (2) manual workers aged over 40 years; (3) long-term repeated lower back pain and intermittent claudication, alleviated lower back pain in the position of forward flexion, and aggravated lower back pain in the position of backward extension, bilateral leg pain or alternative leg pain, lower back and leg numbness and weakness, and aggravated lower back pain and intermittent claudication when standing and walking but improved after a rest or frequent urination or dysuria, even in severe cases; (4) lower-extremity muscle atrophy, decreased tendon reflex, and positive lower back extension test; (5) myelography, computed tomography (CT), and magnetic resonance imaging (MRI) findings showing signs of lumbar spinal stenosis.
- Age 65–74 years
- Presence of neurological dysfunction corresponding to nerve root compression
- Provision of informed consent
Participants with one or more of the following diseases will be excluded from this study:
- Vasculogenic claudication
- Lumbar disc herniation
- Spinal tuberculosis
- Ankylosing spondylitis
- Rheumatoid arthritis
- Spine fracture
Grouping and blinding
This is a self-control study. It will be performed to investigate changes in outcome measures in older adult patients with degenerative lumbar spinal stenosis undergoing total laminectomy combined with lumbar pedicle screw fixation. Randomization and blind grouping will not be performed.
| Interventions|| |
Prior to surgery, the spinal stenosis site will be determined according to clinical manifestations and imaging findings. Continuous epidural anesthesia will be performed while the patient is lying in the lateral position. Loci will be located using a C-arm fluoroscopic X-ray device, and then marked. A longitudinal median incision will be made on the lumbar spine using a posterior approach to fully expose the laminae on both sides of the spine, transverse process, and superior and inferior articular processes. Pedicle screws will be placed using a “free-hand” technique. During surgery, C-arm fluoroscopy will be performed to ensure the correct screw position. Bone material will be obtained from Shanghai Yapeng Biotechnology Co., Ltd. (Shanghai, China).
According to a previous method (Guo et al., 2012), the entire lamina at narrowed spinal canal segments and thickened yellow ligament will be resected. The lateral recess and nerve root canal will be palpated. Partial, or the whole, articular process will be removed with a detacher. Decompression will end when a dural sac bulge and nerve root relaxation are detected, and the movable range approaches 1 cm. Annulus fibrosus will be cut open. Degenerative disc tissue will be resected using a nucleus pulposus forceps. Fibrocartilage and subchondral cortex in the intervertebral space will be scraped using a curette for bone grafting. Connecting rods will be installed for intervertebral distraction. After spondylolisthesis reduction, decompressive bone fragments will be used for intervertebral bone grafting [Figure 1]. The connecting rods (which will be pre-bent at the curvature, consistent with lumbar physiological lordosis) will be installed and the nuts tightened. Horizontal connecting rods will then be installed. After rinsing and suturing the wound, a drainage tube will be inserted.
|Figure 1: Procedure of total laminectomy combined with lumbar pedicle screw fixation.|
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After surgery, antibiotics will be routinely used to prevent infection. Dexamethasone and mannitol will be used to reduce edema. Next, a drainage tube will be inserted. Rehabilitative guidance will be given to the patients.
Criteria for termination or modification of interventions assigned to subjects
If the researchers find that the risks outweigh the potential benefit, or have come to the conclusion that the risk is sufficient to undermine the safety and efficacy of surgery, they will inform the subjects that the clinical trial is to be suspended or terminated, and ensure that the subjects receive appropriate treatment and follow-up. In addition, the researchers will inform the sponsor and ethics committee, and provide a detailed written explanation regarding suspension or termination of the clinical trial.
Recovery rate in Japanese Orthopedic Society (JOA) score at 12 months post-surgery will be used to evaluate improvements in the patient's lower back and leg pain. JOA score ranges from 0 to 29 (Yang et al., 2009). Lower JOA score indicates more severe dysfunction. Recovery index = JOA score after surgery – JOA score before surgery. Recovery rate in JOA score = [(JOA score after surgery – JOA score before surgery)/(15 – JOA score before surgery)] × 100%. The recovery index will be used to reflect improvements in lumbar function after surgery. Recovery rate in JOA score will be used to evaluate clinical efficacy: 100% recovery rate indicates healed, > 60% indicates highly effective, 25–60% effective, and < 25% ineffective.
- JOA score pre-surgery and at 3, 6, 9 and 12 months post-surgery: to evaluate improvements in lower back and leg pain. The scoring system is the same as above.
- Spinal canal diameter pre-surgery and at 3, 6, 9 and 12 months post-surgery: the lower back will be scanned using a 64-slice spiral CT scanner (GE Healthcare, Bethesda, MD, USA) to measure the diameter of the relevant spinal canal.
- Lumbar spine morphology pre-surgery and at 3, 6, 9 and 12 months post-surgery: the morphology of spinal canal and root canal sections will be obtained using a 64-slice spiral CT scanner to observe bone fusion at loci. The patients will be asked to lie in the supine position with their body in the middle of the bed and arms overhead. The knees will be elevated with leg pads. Physiological curvature of the lumbar spine will be kept parallel to the examination bed, as far as possible. Continuous transverse scanning of the relevant lumbar spine segments will be performed. Related lumbar spine segments will be scanned at the lateral view to determine scan range, layer thickness, and layer interval. Scan range: intervertebral discs or the vertebral body will be scanned according to clinical requirements. Scanning gantry tilt: will be appropriately tilted according to lateral position images.
- Incidence of adverse events at 3, 6, 9 and 12 months post-surgery: the incidence of postoperative complications at the last follow-up will be calculated. Incidence of adverse events = number of patients with adverse reactions / total number of patients × 100%.
- Schedule of outcome measures
- The schedule of outcome measures is shown in [Table 2].
Any medical abnormalities occurring from recruitment to the end of the observation period, regardless of whether they are directly associated with the surgical treatment, will be considered adverse events. During the study period, adverse events (including name, start and end time, severity, relationship with known events, and treatment measures) will be accurately recorded. Possible adverse events of this study include: lumbar intervertebral bulge, lumbar lacunar stenosis, degenerative spondylolisthesis, infection, shock, and limb numbness.
Judgment and treatment of severe adverse events: any medical events including death, prolonged hospitalization, re-hospitalization, fetal diseases, permanent defects in body structure or body function, and medical treatment or surgical intervention to avoid permanent defects in body structure or body function, will be considered as severe adverse events. During follow-up, the start time and type of severe adverse events as well as the treatment measures will be recorded in detail. After adverse events occur, relevant information will be reported to the principal investigator and the institutional review board within 24 hours.
Study flow chart
Total laminectomy combined with lumbar pedicle screw fixation will be performed in 160 older adult patients with degenerative lumbar spinal stenosis. These patients will be followed up at 3, 6, 9 and 12 months post-surgery [Figure 2].
In accordance with our experience, we hypothesized that the recovery rate in JOA score at 12 months post-surgery is 80%. Taking β = 0.2, power = 80%, α = 0.05 (two-sided), a final effective sample size of n = 132 was calculated using PASS 11.0 software (PASS, Kaysville, UT, USA). Assuming a participant loss rate of 20%, we require 160 participants per group.
All data will be statistically processed using SPSS 19.0 software (IBM, New York, NY, USA), following the intention-to-treat principle. Normally distributed measurement data will be expressed as mean, standard deviation, minimum, and maximum. Non-normally distributed data will be expressed as lower quartile (q1), median, and upper quartile (q3).
Selection of statistical methods
McNemar chi-square test will be used to compare recovery rate in JOA score and incidence of reverse events between pre-surgery and different time points post-surgery. Repeated measures analysis of variance will be used to compare JOA score and spinal canal diameter between pre-surgery and different time points post-surgery. An inspection level of α = 0.05 (unilateral) will be considered.
Subject selection criteria and reasons
Included subjects consist of populations assigned to the full analysis set and per protocol set.
Full analysis set: refers to the set of subjects that is as close as possible to the ideal implied by the intention-to-treat principle. Specifically, the set of subjects that participate in the treatment and can provide baseline efficacy. For subjects whose follow-up observations may be missing, the last observation will be used.
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.
If the two sets provide consistent statistical conclusions, then the results of the study are reliable. If the analytical results of the two sets are inconsistent because of marked differences in the number of subjects, then the analytical results of the full analysis set will be used.
Patient's baseline information is shown in [Table 3].
Data collection and management
Case report forms will be filled out by the investigators accurately, completely, and on time. Written records including demographic information, disease classification, accompanying diseases, and adverse events will be transferred to an electronic format by professional staff using a double data entry strategy.
All observations and findings of the clinical trial will be verified to ensure data reliability, and that the conclusions from the clinical trial are derived from the original data. This will also ensure that the database is locked by the project manager. All relevant data will be stored by Qinghai Provincial People's Hospital.
Data monitoring committee composition
The data monitoring committee is comprised of relevant clinical specialists, including at least one statistician familiar with data statistics methods and data analysis, one ethics expert with clinical design knowledge, and experts in clinical pharmacology, epidemiology, and toxicology.
All surgeons participating in this study have a wealth of orthopedic surgery experience. The physicians evaluating JOA scores and imaging findings will all receive professional training and use unified data recording and judgment criteria. Experimental data processing and statistical calculations will be performed by statisticians.
During the trial, regular audits will be performed to ensure the trial is performed in strict accordance with the study protocol, and that related data are accurate, complete, and correct.
Compensation to study participants
Patients included in this program will receive appointments from a panel of well-known experts in the hospital without having to pay for the examination fees, and also receive a transportation allowance.
Compensation to study participants with adverse events
A compensation agreement will be assigned before the start of the clinical trial at the discretion of the sponsor and investigators after thorough consideration, and will be used if the study participants require economic compensation. If drug-related adverse reactions occur, study participants will be eligible for economic compensation as per the assigned economic compensation agreement.
Ethics and dissemination
This study was approved by the Medical Ethics Committee of Qinghai Provincial People's Hospital of China (approval No. QHY201602G). This study will be performed in strict accordance with the Declaration of Helsinki formulated by the World Medical Association. Participants will provide signed informed consent prior to participation in the study. When the investigators discover an unexpected risk in the clinical trial, the investigators and sponsor will jointly modify the content of the informed consent form. After receiving agreement by the medical ethics committee, the affected study participants or their guardians will re-sign the amended informed consent.
| Preliminary Results|| |
Results from a preliminary study involving 71 patients with degenerative lumbar spinal stenosis, who were followed up for 3 months, have been published (Guo et al., 2012).
General information of patients included in the preliminary study
Seventy-one patients, 42 males and 29 females, aged 69.9 ± 4.1 (65–74) years, were included in the preliminary study. These patients clinically manifested different levels of lower back and leg pain. Lower back pain was observed in 67 patients, lower extremity pain in 59 patients, decreased sensation of lower extremities in 47 patients, decreased sensation of the perineal region in 12 patients, and abnormal knee tendon reflexes and Achilles tendon reflexes in 38 patients. Imaging examination showed that one lumbar spine segment was involved in 32 (43.8%) patients, and two or more lumbar spine segments in 41 (56.2%) patients. All these patients developed varied levels of osteoporosis.
Relief of lower back pain
JOA score at 3 and 12 (last follow-up) months post-surgery was significantly increased compared with before surgery (P < 0.05; [Table 4]).
|Table 4: Relief of lower back pain in older adult patients with degenerative lumbar spinal stenosis after total laminectomy combined with lumbar pedicle screw fixation|
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Spinal canal diameter
Spinal canal diameter at 3 and 12 months post-surgery (17.6 ± 3.2 mm and 16.9 ± 2.9 mm) was significantly greater compared with before surgery (P < 0.05).
| Discussion|| |
Past contributions and existing problems of other scholars in this field of research
Senile degenerative lumbar spinal stenosis develops slowly over time, which is serious, and even leads to degenerative spondylolisthesis and spine instability. Conventional surgery cannot achieve a desirable repair effect.
Features of this study
Total laminectomy combined with lumbar pedicle screw fixation for treatment of senile degenerative lumbar spinal stenosis exhibits striking clinical efficacy, but several key points should be considered during surgery: (1) every necessary examination should be performed before surgery and the lesions accurately located; (2) surgical treatment should not be performed in patients without surgical indications; (3) surgery will be performed by experienced surgeons in strict accordance with surgical procedures; (4) careful postoperative care should be provided to avoid surgical complications; and (5) surgical complications should be effectively treated in time.
Limitations of this study
Based on the number of previous visits for treatment of senile degenerative lumbar spinal stenosis, in this study we have only used a self-control design rather than a conventional surgery group as controls. This likely affects the accuracy of the results and will be addressed in future studies.
Significance of this study
Total laminectomy combined with lumbar pedicle screw fixation for treatment of senile degenerative lumbar spinal stenosis can rapidly relieve a patient's symptoms and provide spine stability. Findings from this study will further reveal a suitable method to treat senile degenerative lumbar spinal stenosis.
Additional file 1: SPIRIT checklist. [Additional file 1]
CLL designed the study. KW will be responsible for patient recruitment. Data collection and analysis will be performed by QG, FQ, WQY, and HYZ. CLL, QG and KW contributed to writing of the manuscript. All authors approved the final version of this manuscript for publication.
Conflicts of interest
There are no competing interests to delare.
This study was approved by Medical Ethics Committee of Qinghai Provincial People's Hospital of China (approval No. QHY201602G). The study will be performed in accordance with the Declaration of Helsinki.
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.
Data sharing statement
Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices) will be in particular shared. Study protocol and informed consent form will be available. The data will be available immediately following publication without end date. 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 www.figshare.com.
Checked twice by iThenticate.
Externally peer reviewed.
| References|| |
Asher MA, Carson WL, Hardacker JW, Lark RG, Lai SM (2007) The effect of arthrodesis, implant stiffness, and time on the canine lumbar spine. J Spinal Disord Tech 20:549-559.
Benyamin RM, Staats PS, MiDAS Encore I (2016) MILD® is an effective treatment for lumbar spinal stenosis with neurogenic claudication: MiDAS ENCORE randomized controlled trial. Pain Physician 19:229-242.
Bernard F, Lemée JM, Lucas O, Menei P
(2017) Postoperative quality-of-life assessment in patients with spine metastases treated with long-segment pedicle-screw fixation. J Neurosurg Spine 26:725-735.
Elies W (1979) Esophageal complications following ventral cervical disc surgery (author's transl). HNO 27:380-381.
Guo Q (2012) Treatment of senile degenerative lumbar spinal stenosis with total laminectomy and spinal internal fixation. Zhongguo Laonianxue Zazhi 32:4792-4793.
Hao ZY, Wei YD, Kong JJ (2010) Surgical treatment of senile degenerative lumbar spondylolisthesis with lumbar spinal canal stenosis. Hebei Yiyao 32:1924-1925.
Ledet EH, Carl AL, DiRisio DJ (2002) A pilot study to evaluate the effectiveness of small intestinal submucosa used to repair spinal ligaments in the goat. Spine J 2:188-196.
Li HB, Zhang XQ, Chen SM (2008) Recapping laminoplasty for the treatment of severe burst fractures of thoracolumbar vertebra complicated with spinal stenosis. Zhongguo Gushang 21:445-446.
Li YJ, Xu HZ, Chen BL (2011) Comparative study of the efficacy of non-surgical and surgical therapy for degenerative lumbar spinal stenosis. Nanfang Yike Daxue Xuebao 31:190-193.
Liu RL (2004) Lumbar spinal stenosis. Zhonguo Jiaoxing Waike Zazhi 12:1514-1516.
Matsukawa K, Yato Y, Hynes RA (2017) Comparison of pedicle screw fixation strength among different transpedicular trajectories: a finite element study. Clin Spine Surg 30:301-307.
Moojen WA, Arts MP, Jacobs WC, van Zwet EW, van den Akker-van Marle ME, Koes BW, Vleggeert-Lankamp CL, Peul WC; Leiden The Hague Spine Intervention Prognostic Study Group (SIPS) (2015) IPD without bony decompression versus conventional surgical decompression for lumbar spinal stenosis: 2-year results of a double-blind randomized controlled trial. Eur Spine J 24:2295-2305.
Moojen WA, Arts MP, Jacobs WC, van Zwet EW, van den Akker-van Marle ME, Koes BW, Vleggeert-Lankamp CL, Peul WC; Leiden-The Hague Spine Intervention Prognostic Study Group (2013) Interspinous process device versus standard conventional surgical decompression for lumbar spinal stenosis: randomized controlled trial. BMJ 347:f6415.
Na GY, Han XG, Chi TH (2011) Surgical treatment of senile degenerative lumbar spinal stenosis. Zhongguo Dangdai Yiyao 18:164-165.
Ren L, Zhang JX (2010) 52 cases of elderly patients with the degenerative lumbar spinal stenosis treated by laminectomy and internal fixation of spine. Shiyong Zhongyiyao Zazhi 26:852-853.
Seo DK, Kim MJ, Roh SW, Jeon SR (2017) Morphological analysis of interbody fusion following posterior lumbar interbody fusion with cages using computed tomography. Medicine (Baltimore) 96:e7816.
Vasilenko II, Klimov VS, Evsyukov AV (2015) A change in the sagittal balance in elderly and senile patients with degenerative stenosis of the lumbar spine. Zh Vopr Neirokhir Im N
N Burdenko 79:102-107.
Verhoof OJ, Bron JL, Wapstra FH (2008) High failure rate of the interspinous distraction device (X-Stop) for the treatment of lumbar spinal stenosis caused by degenerative spondylolisthesis. Eur Spine J 17:188-192.
Wang Z, Su F, Zhang X, Yan S, Zhang Z (2017) Effect of transverse position and numbers on the stability of the spinal pedicle screw fixation during the pedicle cortex perforation. Zhongguo Yi Xue Ke Xue Yuan Xue Bao 39:365-370.
Yang JS, Liao ZW, Hang WD (2009) Effect of B-Twin intervertebral cage in treating lumbar degenerative instability with posterior mini-incision. Zhonguo Jiaoxing Waike Zazhi 17:986-989.
Ye C, Luo Z, Yu X, Liu H, Zhang B, Dai M (2017) Comparing the efficacy of short-segment pedicle screw instrumentation with and without intermediate screws for treating unstable thoracolumbar fractures. Medicine (Baltimore) 96:e7893.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]