Two-Year Outcomes of Midline lumbar Fusion Versus Minimally Invasive Transforaminal Lumbar Interbody Fusion in the Treatment of L4-L5 Degenerative Disease

Objective We aimed to compare the clinical and radiological outcomes of midline lumbar fusion(MIDLF)versus minimally invasive transforaminal lumbar interbody fusion(MI-TLIF)in patients with degenerative spondylolisthesis and/or stenosis in L4-L5 two years after surgery.Methods Consecutively treated patients with lumbar pathology who underwent MIDLF(n=16)and a historical control group who underwent MI-TLIF(n=34)were included.Clinical symptoms were evaluated using Oswestry Disability Index(ODI),the 36-Item Short-Form Health Survey,and visual analog scale(VAS)scores before surgery and 3,6,12,and 24 months after surgery.Results The mean operative time and hematocrit(HCT,Day 1)were significantly shorter and lower in MIDLF cases(174 min vs.229 min,P<0.001;0.34 vs.0.36,P=0.037).The MI-TLIF group showed better improvement than the MIDLF group in ODI and VAS back and leg pain at 3 months postoperatively.VAS leg pain was higher in MIDLF than in MI-TLIF cases at 6 months.At 24 months follow-up,VAS back pain was higher in MI-TLIF than in MIDLF cases(P=0.018).Conclusion MIDLF is comparable to MI-TLIF at L4-5 in clinical outcomes and fusion rates,and the results verified the meaningful advantage of using MIDLF for the elderly with osteoporosis.

Can bone mineral density affect intra-operative blood loss of mini-invasive posterior lumbar interbody fusion?

Objective:Many factors affect intraoperative blood loss(BL)in mini-invasive posterior lumbar interbody fusion(PLIF)procedures,but only few has examined.Specifically,the impact of bone mineral density(BMD)levels on intraoperative BL.This study aims to examine the correlation between these two factors.Methods:Retrospective review of 120 patients with low back disorders who were scheduled to undergo mini-invasive PLIF from October 2018 to October 2019 was performed.Patients were divided into two groups based on BMD of the lumbar spine:normal group and abnormal group(osteoporosis and osteopenia).Comparison of age,gender,BMD,BL,BMI,prothrombin time,activated partial thromboplastin time,haemoglobin concentration,intraoperative mean arterial pressure,platelet count,and operative time(OT)between the two groups,and correlation analysis of BMD and BL were conducted.Results:The mean BL of patients in the abnormal group was remarkably higher than that in the normal group:357.22±152.55 ml and 259.37±125.90 ml respectively(p<0.001).The partial correlation coefficient between BL and BMD was0.45(p<0.001).The results of univariate regression analysis demonstrated that only BMD,gender,and OT were related to BL(BMD,r=0.427,p<0.001;gender,r=0.211,p=0.024;OT,r=0.318,p=0.001).While multivariate linear regression analysis demonstrated that patients with lower BMD and longer OT had a higher amount of intraoperative BL(p<0.001).Conclusions:BMD is an important factor influencing intraoperative BL in mini-invasive PLIF.It should be assessed routinely as a part of the preoperative examination to improve preoperative assessment and ensure patient safety.

Correlation study between the changes of motor evoked potential and the improvement of spinal canal volume in minimally invasive transforaminal lumbar interbody fusion

Objective:To analyze the correlation between the amplitude changes of motor evoked potential(MEP),the 3D volume changes of spinal canal measuring by postoperative CT and the improvement rate of clinical symptoms after the spinal canal decompression in minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF),and to explore the predictive value of the changes of both MEP amplitude and spinal canal volume in the assessment of long-term clinical prognosis in MIS-TLIF.Methods:A retrospective study of 68 patients with L4/5 spinal stenosis treated with MIS-TLIF was performed.The changes of both intraoperative MEP amplitude and 3D spinal canal volume during the spinal canal decompression,as well as the visual analogue scale(VAS)and Oswestry dysfunction index(ODI)scores in the long-term follow-up were all recorded.Results:The values of intraoperative MEP amplitude was 159.04%higher in 68 patients with MIS-TLIF after spinal canal decompression(P<0.01).The 3 postoperative 3D spinal canal volume(4.89±1.27)cm increased by 31.22%in comparison 3 with preoperative date(3.78±1.08)cm(P<0.01).The VAS and ODI scores were improved to 78.55%and 80.60%,respectively at the last follow-up(P<0.01).The improvement rate of MEP amplitude on the decompression side was positively correlated with the improvement rate of postoperative spinal canal volume(r=0.272,P=0.025).The improvement rate of postoperative spinal canal volume was positively correlated with the improvement rate of VAS and ODI at the last follow-up(r=0.656,r=0.490,P<0.01).Moreover,the improvement rate of MEP amplitude on the decompression side was also positively correlated with the improvement rate of VAS and ODI at the last follow-up(r=0.322 and 0.235,respectively,P<0.05).Conclusion:The increase of MEP amplitude after spinal canal decompression in patients with lumbar spinal stenosis treated by MIS-TLIF was closely correlated with both of the increase of spinal canal volume and the improvement of clinical symptoms.Therefore,MEP amplitude monitoring was not only the one of the important monitoring methods for predicting the prognosis of MIS-TLIF but also the reliably predictive value in the long-term clinical prognosis in MIS-TLIF.

Comparison of Clinical Outcomes of Cortical Bone Trajectory and Traditional Pedicle Screw Fixation in Posterior Lumbar Interbody Fusion

Posterior lumbar interbody fusion (PLIF) is a common surgical procedure and widely used in the treatment of lumbar degenerative disc disorders. Traditionally, posterior lumbar interbody fusion is done by using the traditional pedicle screw (PS) which offers great advantages, but at the same time it has some disadvantages which include the risk of superior facet joint violation and muscle damage. Recently, an alternative method of screw insertion via cortical bone trajectory (CBT) has been invented which has less invasive process and can be placed without the drawbacks associated with the traditional pedicle screw. However, it has to remain an interest whether CBT will provide similar or greater clinical outcomes compared to PS in PLIF. So the main aim of this review is to compare the clinical outcomes of cortical bone trajectory and traditional pedicle screw fixation in posterior lumbar interbody fusion based on the articles published on this topic. Compared to the traditional pedicle screw fixation, PLIF with CBT has similar clinical outcome based on pain intensity, ODI status and JOA score, as well as similar fusion rate and radiological evaluated complication such as loosening of screw. In addition PLIF with CBT has advantages of less facet joint violation, less blood loss, less intraoperative muscle damage and perioperative pain. On the basis of this study, we can suggest that PLIF with CBT can be considered as a reasonable alternative to PS in PLIF.

Risk factors and care of early surgical site infection after primary posterior lumbar interbody fusion

Objectives:To explore the risk factors and nursing measures of early surgical site infection(SSI)after posterior lumbar interbody fusion(PLIF).Methods:A total of 468 patients who received PLIF in our hospital from January 2017 to June 2020 were enrolled into this study.According to the occurrence of early SSI,the patients were divided into two groups,and the general data were analyzed by univariate analysis.Multivariate logistic regression analysis was conducted with the dichotomous variable of whether early SSI occurred and other factors as independent variables to identify the risk factors of early SSI and put forward targeted prevention and nursing measures.Results:Among 468 patients with PLIF,18 patients developed early SSI(3.85%).The proportion of female,age,diabetes mellitus and urinary tract infection(UTI),operation segment,operation time,post-operative drainage volume,and drainage time were significantly higher than those in the uninfected group,with statistical significance(P<0.05),whereas the preoperative albumin and hemoglobin in the infected group were significantly lower than those in the uninfected group,with statistical significance(P<0.05).There was no significant difference between the two groups in the American Society of Anesthesiologists(ASA)grading,body mass index(BMI),complications including cardiovascular and cerebrovascular diseases or hypertension(P>0.05).Logistic regression analysis showed that preoperative diabetes mellitus(OR=2.109,P=0.012)/UTI(OR=1.526,P=0.035),prolonged drainage time(OR=1.639,P=0.029)were risk factors for early SSI.Men(OR=0.736,P=0.027)and albumin level(OR=0.526,P=0.004)were protective factors in reducing early SSI.Conclusions:Women,preoperative diabetes/UTI,hypoproteinemia,and prolonged drainage time are risk factors for early SSI after PLIF.Clinical effective preventive measures should be taken in combination with targeted nursing intervention to reduce the risk of early SSI.

Biomechanical Effects of Implant Materials on Posterior Lumbar Interbody Fusion: Comparison of Polyetheretherketone and Titanium Spacers Using Finite Element Analysis and Considering Bone Density

Few biomechanical data exist regarding whether the polyetheretherketone (PEEK) spacer or titanium spacer is better for posterior lumbar interbody fusion (PLIF). This study evaluated the biomechanical influence that these types of spacers with different levels of hardness exert on the vertebra by using finite element analysis including bone strength distribution. To evaluate the risk of spacer subsidence for PLIF, we built a finite element model of the lumbar spine using computed tomography data of osteoporosis patients. Then, we simulated PLIF in L3/4 and built models with the hardness of the interbody spacer set as PEEK and titanium. Bones around the spacer were subjected to different load conditions. Then, fracture elements and some stress states of the two modalities were compared. In both models of PLIF simulation, fracture elements and stress were concentrated in the bones around the spacer. Fracture elements and stress values of the model simulating the PEEK spacer were significantly smaller compared to those of the titanium simulation model. For PLIF of osteoporotic vertebrae, this suggested that the PEEK spacer is in a mechanical environment less susceptible to subsidence caused by microfractures of bone tissue and bone remodeling-related fusion aspects. Therefore, PEEK spacers are bio-mechanically more useful.

Delayed arterial symptomatic epidural hematoma on the 14th day after posterior lumbar interbody fusion:A case report

BACKGROUND Delayed arterial symptomatic epidural hematoma(SEH)on the 14th day after posterior lumbar interbody fusion(PLIF)is rare but it may lead to severe complications if not identified and treated in a timely manner.After diagnosis of the current case,early surgical removal of the hematoma and strict hemostasis treatment was accomplished.This case report highlights the importance of swift diagnosis and treatment in SEH patients.CASE SUMMARY A 41-year-old male patient with a single-segment lumbar disc herniation underwent left-side PLIF.On the 14th post-operative day,the patient complained of lumbar incision pain with sudden onset accompanied by left limb radiation pain and aggravated cauda equina symptoms.Magnetic resonance imaging examination and a puncture blood draw at the incision site confirmed a delayed arterial SEH.Emergency surgical removal of the hematoma and hemostasis was performed.About 70 mL of hematoma was found in the left incision.Continuous bleeding was found in the anterior branch of the transverse process of the 4th lumbar artery in the muscle area about 2 cm below the transverse process of the 4th lumbar vertebra.A blood jet of about 10 cm in height was observed and bipolar electrocoagulation was used to stop the bleeding.Post-operative lumbar incision pain and left lower limb pain were relieved immediately and gradually disappeared.There was no recurrence during the 12-mo follow-up.CONCLUSION For delayed arterial SEH on the 14th day after PLIF,preventive measures including pre-,intra-and post-operative prevention should be implemented.

Use of Nonlinear Finite Element Analysis of Bone Density to Investigate the Biomechanical Effect in the Bone around Intervertebral Cages in Posterior Lumbar Interbody Fusion

Preventing subsidence of intervertebral cages in posterior lumbar interbody fusion (PLIF) requires understanding its mechanism, which is yet to be done. We aimed to describe the mechanism of intervertebral cage subsidence by using finite element analysis through simulation of the osteoporotic vertebral bodies of an elderly woman. The data from computed tomography scans of L2-L5 vertebrae in a 72-year-old woman with osteoporosis were used to create 2 FE models: one not simulating implant placement (LS-INT) and one simulating L3/4 PLIF using polyetheretherketone (PEEK) cages (LS-PEEK). Loads and moments simulating the living body were applied to these models, and the following analyses were performed: 1) Drucker-Prager equivalent stress distribution at the cage contact surfaces;2) the distribution of damage elements in L2-L5 during incremental loading;and 3) the distribution of equivalent plastic strain at the cage contact surfaces. In analysis 1, the Drucker-Prager equivalent stress on the L3 and L4 vertebral endplates was greater for LS-PEEK than for LS-INT under all loading conditions and tended to be particularly concentrated at the contact surfaces. In analysis 2, compared with LS-INT, LS-PEEK showed more damage elements along the bone around the cages in the L3 vertebral body posterior to the cage contact surfaces, followed by the area of the L4 vertebral body posterior to the cage contact surfaces. In analysis 3, in the L3 inferior surface in LS-PEEK the distribution of equivalent plastic strain was visualized as gradually expanding along the cages from the area posterior to the cages to the area anterior to them with increased loading. These analyses suggested that in PLIF for osteoporotic vertebral bodies, the localized stress concentration generated by the use of PEEK cages may cause accumulation of microscopic damage in the fragile osteoporotic vertebral bodies around the cages, which may result in cage subsidence.

Posterior Lumbar Interbody Fusion versus Posterolateral Fusion in Surgical Treatment of Lumbar Spondylolithesis

Background: The optimal surgical technique for lumbar spondylolithesis remains debated. Although posterior lumbar interbody fusion (PLIF) theoretically offers more advantages than posterolateral lumbar fusion (PLF), the evidence remains inconclusive. Aim: The aim of this study is to compare the clinical and functional outcomes of PLIF versus PLF in patients with lumbar spondylolithesis. Patients and Methods: We enrolled 38 patients with lumbar spondylolithesis (degenerative and isthmic) who underwent PLIF (N = 19) or PLF (N = 19). We collected operative data and performed follow-up for 12 months after the surgery. The collected data were analyzed using the SPSS software to detected significant differences between both groups. Results: The PLF and PLIF groups exhibited similar pre-operative characteristics between both groups in terms of age (p = 0.57), sex (p = 0.73), clinical presentation (p = 1), required levels of fixation (p = 1), pre-operative VAS score (p = 0.43) or muscle weakness (p = 1). However, the PLIF group had significantly more blood loss and longer operative time than the PLF group. Moreover, both groups had similar levels of postoperative pain (up to six months after surgery), and post-operative complications. The rates of arthrodesis were higher in PLIF group than PLF group within six months while no significant difference within 12 months of follow-up. Conclusion: In our comparative study, we achieved comparison between pedicle screw fixation with posterolateral fusion alone (PLF) in compare with pedicle screw fixation with posterior lumbar interbody fusion (PLIF). Results indicate better results of fusion rate in PLIF as regards arthrodesis with slightly more rate of complication than PLF. So we recommend PLIF in cases of lumbar spondylolithesis than PLF.

Surgical Results of Posterior Lumbar Interbody Fusion with Transpedicular Fixation in Management of Spondylolisthesis

Objective: To evaluate the surgical results of posterior lumber interbody fusion with transpedicular fixation with rod screw system in management of spondylolisthesis. Study Design: Retrospective study reviewed all patient treated by lumber interbody fusion with transpedicular fixation with rod screw system. Patients and Methods: They were 40 patients operated for lumber and lumbosacral spondylolisthesis from Feb 2014 to April 2017 in Al-Azhar university hospital. These patients followed postoperatively clinically for improved neural function and for fusion stability and hardware fixation by radiological investigation. Data about pain intensity (by Visual Analogue Scale) was collected pre- and postoperatively;and outcome was assessed by Oswetry disability index (ODI). Outcome was graded as excellent, good, fair, or poor. Pre- and Post-operative data were statistically compared. Results: The mean age was 45 years (range between 30 - 60 years) with female sex predominance (male:female = 1:3). They had lytic (n = 30) or degenerative (n = 10) spondylolisthesis;and all underwent PLIF (posterior lumbar interbody fusion). In lytic group, the level was L4/L5 in 19 patients and L5/S1 in 11 patients, while in degenerative group the level was L4/L5 in 4 patients, L5/S1 in 3 patients, L2/L3 in 2 and L3/L4 in one patient. The spondylolisthesis grade was grade I among 25 subjects, grade two among 11 subjects and retrolisthesis among 4 subjects. Sensory deficits reported in 22 subjects (19 had lytic and 3 had degenerative spondylolisthesis);while motor deficits reported among 10 subjects and reduced reflexes among 8 subjects. The outcome was excellent, good, and fair among 30, 7, and 3 subjects respectively. The return to previous levels of activity was reported among 32 patients. VAS was 3.5 ± 2.94 at the end of follow up, while ODI was 28% and 36.0% and 3 and 6 months respectively. Conclusion: PLIF associated with transpedicular rod screw fixation system for management of spondylolisthesis is considered a safe and effective surgical intervention in both lytic and degenerative types.

Minimally invasive procedures on the lumbar spine

Degenerative disease of the lumbar spine is a common and increasingly prevalent condition that is often implicated as the primary reason for chronic low back pain and the leading cause of disability in the western world. Surgical management of lumbar degenerative disease has historically been approached by way of open surgical procedures aimed at decompressing and/or stabilizing the lumbar spine. Advances in technology andsurgical instrumentation have led to minimally invasive surgical techniques being developed and increasingly used in the treatment of lumbar degenerative disease. Compared to the traditional open spine surgery, minimally invasive techniques require smaller incisions and decrease approach-related morbidity by avoiding muscle crush injury by self-retaining retractors, preventing the disruption of tendon attachment sites of important muscles at the spinous processes, using known anatomic neurovascular and muscle planes, and minimizing collateral soft-tissue injury by limiting the width of the surgical corridor. The theoretical benefits of minimally invasive surgery over traditional open surgery include reduced blood loss, decreased postoperative pain and narcotics use, shorter hospital length of stay, faster recover and quicker return to work and normal activity. This paper describes the different minimally invasive techniques that are currently available for the treatment of degenerative disease of the lumbar spine.

One Stage Anterior Reconstruction and Posterior Instrumentation in Surgical Management of Thoracolumbar Spine Fractures

Background: The different methods of anterior reconstruction and posterior instrumentation in surgical management of thoracolumbar spine fractures are PLIF, TLIF, lateral extracaviatary and transpedicular techniques which are increasingly used to perform partial or total corpectomies and anterior reconstructions from a posterior approach. These techniques were being alternative to the standard anterior approach with less morbidity and mortality. Patients and Methods: This study was performed between 2011 and 2014 on 100 patients with acute unstable thoracolumbar spine fractures which were divided into four groups: 30 patients underwent (TLIF), 28 patients underwent (PLIF), 28 patients underwent (PA) and 14 patients underwent (TPA). Neurological outcome, complications, operative times, kyphotic angle, vertebral height loss, spinal canal compromise, pulmonary functions, Denis pain and work scale, VAS score, ODI score, hospital stay, and estimated blood loss (EBL) were evaluated and compared in between the four groups. Results: There was a higher complication rate, increased EBL, and longer operative time with posteroanterior (PA) compared with PLIF, TLIF and (TPA). Patients undergoing PLIF, TLIF and TPA had a greater recovery of neurological function than those in whom PA were performed. Conclusion: TPA appeared to have more favorable results in improving the clinical and radiological outcome and no complications were reported apart from superficial wound infection which healed rapidly. The PLIF, TLIF and TPA appeared to have a comparable morbidity rate to PA. The different methods of anterior reconstruction from posterior approach are more favorable, applicable and convenient than PA approach.

Radiological and clinical outcomes of midline lumbar fusion on sagittal lumbar-pelvic parameters for degenerative lumbar diseases

BACKGROUND Improving the sagittal lumbar-pelvic parameters after fusion surgery is important for improving clinical outcomes.The impact of midline lumbar fusion(MIDLF)on sagittal lumbar-pelvic alignment for the management of degenerative lumbar diseases is still unknown.AIM To analyze the effects of short-segment MIDLF and minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF)on sagittal lumbar-pelvic parameters.METHODS We retrospectively analyzed 63 patients with degenerative lumbar diseases who underwent single-segment MIDLF or MIS-TLIF.The imaging data of patients were collected before surgery and at the final follow-up.The radiological sagittal parameters included the lumbar lordosis(LL),lower LL,L4 slope(L4S),L5 slope(L5S),L5 incidence(L5I),L1 axis and S1 distance(LASD),pelvic incidence(PI),pelvic tilt(PT),sacral slope(SS),and PI-LL mismatch(PI-LL).Additionally,the clinical outcomes,including lower back and leg pain visual analog scale(VAS)and Oswestry disability index(ODI)scores,were also analyzed.RESULTS In both groups,LL and Lower LL significantly increased,while L5I and LASD significantly decreased at the final follow-up compared to that recorded prior to operation(P<0.05).In the MIDLF group,L4S significantly decreased compared to that recorded prior to operation(P<0.05),while the mean SS significantly increased and the PT significantly decreased compared to that recorded prior to operation(P<0.05).In the MIS-TLIF group,SS slightly increased and the mean PT value decreased compared to that recorded prior to operation,but without a statistically significant difference(P>0.05).However,the PI-LL in both groups was significantly reduced compared to that recorded prior to operation(P<0.05).There was no significant difference in the sagittal lumbar-pelvic parameters between the two groups prior to operation and at the final follow-up(P>0.05).In addition,the change in sagittal lumbar-pelvic parameters did not differ significantly,except forΔLASD within the two groups(P>0.05).The mean lower back and leg pain VAS and ODI scores in both groups were significantly improved three months after surgery and at the final follow-up.Though the mean ODI score in the MIDLF group three months after surgery was slightly higher than that in the MIS-TLIF group,there was no significant difference between the two groups at the final follow-up.CONCLUSION Short-segment MIDLF and MIS-TLIF can equally improve sagittal lumbar parameters such as LL,Lower LL,L5I,and LASD in the treatment of lumbar degenerative diseases.However,MIDLF had a larger impact on pelvic parameters than MIS-TLIF.

Minimally invasive lumbar interbody fusion via MAST Quadrant retractor versus open surgery： a prospective randomized clinical trial

In recent years, a variety of minimally invasive lumbar surgery techniques have achieved desirable efficacy, but some dispute remains regarding the advantages over open surgery. This study aimed to compare minimally invasive lumbar interbody fusion via MAST Quadrant retractor with open surgery in terms of perioperative factors, postoperative back muscle function, and 24-month postoperative follow-up results. Methods From September 2006 to June 2008, patients with single-level degenerative lumbar spine disease who were not responsive to conservative treatment were enrolled in this study. Patients were randomized to undergo either minimally invasive surgery （MIS, transforaminal lumbar interbody fusion via MAST Quadrant retractor, 41 cases） or open surgery （improved transforaminal lumbar interbody fusion, 38 cases）. Results The MIS group had longer intraoperative fluoroscopy time than the open surgery group, and the open surgery group had significantly increased postoperative drainage volume and significantly prolonged postoperative recovery time compared with the MIS group （P 〈0.05 for all）. MRI scanning showed that the T2 relaxation time in the multifidus muscle was significantly shorter in the MIS group than in the open surgery group at 3 months after surgery （P 〈0.01）. Surface electromyography of the sacrospinalis muscle showed that the average discharge amplitude and frequency were significantly higher in the MIS group than in the open surgery group （P 〈0.01）. The Oswestry disability index and visual analog scale scores were better at 3, 6, 12 and 24 months postoperatively than preoperatively in both groups. Both groups of patients met the imaging convergence criteria at the last follow-up. Conclusions MIS can effectively reduce sacrospinalis muscle injury compared with open surgery, which is conducive to early functional recovery. In the short term, MIS is superior to open surgery, but in the long term there is no significant difference between the two procedures.

Comparison between Minimally Invasive Transforaminal Lumbar Interbody Fusion and Conventional Open Transforaminal Lumbar Interbody Fusion： An Updated Meta-analysis

Background： The previous studies agree that minimally invasive transforaminal lumbar interbody fusion （MIS-TLIF） has better function outcomes, less blood loss, and shorter hospital stay, when compared to open-TLIF. However, there are no significance differences on operative time, complication, and reoperation rate between the two procedures. This could be from less relative literatures and lower grade evidence. The further meta-analysis is needed with more and higher grade evidences to compare the above two TLIF procedures. Methods： Prospective and retrospective studies that compared open-TLIF and MIS-TLIF were identified by searching the Medline, Embase, Web of Science, China National Knowledge Infrastructure, Wanfang, and VIP database （the literature search comprised Medical Subject Heading terms and key words or Emtree term）. The retrieval time ranged from the date when the database was founded to January 2015. Pooled risk ratios （RRs） and weighted mean differences （WMDs） with 95% confidence intervals were calculated for the clinical outcomes and perioperative data. Results： Twenty-four studies （n =1967 patients） were included in this review （n =951, open-TLIF, n 1016, MIS-TLIF）. MIS-TLIF was associated with a significant decrease in the visual analog score （VAS）-back pain score （WMD 0.44; P= 0.001）, Oswestry Disabilities Index （WMD 1.57; P =0.005）, early ambulation （WMD = -1.77; P = 0.0001）, less blood loss （WMD = -265.59; P 〈 0.00001）, and a shorter hospital stay （WMD =-1.89; P 〈 0.0001）. However, there were no significant differences in the fusion rate （RR =0.99; P = 0.34）, VAS-leg pain （WMD = -0.10; P = 0.26）, complication rate （RR = 0.84; P = 0.35）, operation time （WMD = 5.23; P = 0.82）, or reoperation rate （RR = 0.73; P = 0.32）. Conclusions： MIS-TLIF resulted in a similar fusion rate with better functional outcome, less blood loss, shorter ambulation, and hospital stay; furthermore, it did not increase the complication or reoperation rate based on the existing evidence.

Mast Quadrant-assisted Minimally Invasive Modified Transforaminal Lumbar Interbody Fusion： Single Incision Versus Double Incision

Background： The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion （TLIF） with a small single posterior median incision. Methods： During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision （single incision group）. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index （ODI） scores, Visual Analog Scale （VAS） scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results： A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group （P 〈 0.01）. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups （P _〉 0.05）. Conclusions： Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.

Comparing minimally invasive and open transforaminal lumbar interbody fusion for treatment of degenerative lumbar disease： a meta-analysis

Background Transforaminal lumbar interbody fusion （TLIF） through a minimally invasive approach （mTLIF） was introduced to reduce soft tissue injury and speed recovery. Studies with small numbers of patients have been carried out, comparing mTLIF with traditional open TLIF （oTLIF）, but inconsistent outcomes were reported.

Biomechanical evaluation of two fusion techniques based on finite element analysis:Percutaneous endoscopic and minimally invasive transforaminal lumbar interbody fusion

As a novel minimally invasive technique,percutaneous endoscopic transforaminal lumbar interbody fusion(PETLIF)has been widely used in the treatment of lumbar degenerative diseases.The purpose of this study was to analyze these two operation types’biomechanical performances of PE-TLIF and traditional minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF)using the finite element(FE)method.The intact FE models of L4-L5 were established and validated based on the CT images.On this basis,the FE models of MIS-TLIF and PETLIF were established and analyzed.It is demonstrated that for lumbar interbody fusion with the oblique asymmetrically implanted cage under bilateral pedicle screws and rods fixation,such as MIS-TLIF and PE-TLIF,different degrees of articular process resection have no significant effect on the cage subsidence,and the surgical segment can achieve similar stability.In addition,the maximum stress of the L4 inferior endplate of MIS-TLIF and PE-TLIF is greater than that of the L5 superior endplate,which indicates that MIS-TLIF and PE-TLIF can cause cage subsidence in the L4 inferior endplate.

Instrumentation-related complications of lumbar degenerative disc diseases treated by minimally invasive transforaminal lumbar interbody fusion

Objective:To analyze the instrumentation-related complications of patients with lumbar degenerative disc diseases(LDD)who underwent minimally invasive transforaminal lumbar interbody fusion(MISTLIF)and to discuss the potential strategy for the control of these complications.Methods:A total of 87 patients with LDD were treated with the MIS-TLIF procedure.Complications,including malposition or breakage of guide pin,percutaneous pedicle screw(PPS)or cages,neurological deficit,and superior-level facet joint violations,were determined during and after the surgery.Computed tomography(CT)was used to evaluate the PPS accuracy and the superior-level facet joint violations.Results:A total of 386 PPSs were used.During the surgery,3(0.8%)guide pin and 1(0.3%)PPS perforated the anterior wall of the vertebral body,respectively.One(0.3%)PPS was pulled out during the reduction of slip.Malposition of the cages occurred in 6(1.6%)PPSs.These were all adjusted accordingly during the surgery.All the patients received>2 years of follow-up.No loosening or breakage of PPS and cage was observed,but CT showed 27(7.0%)PPSs misplaced.No neurological deficit related to misplaced PPS was observed.The total facet joint violation(FJV)rate was 36.2%,with grade 2 and grade 3 violations is 21(12.1%)and 6(3.4%),respectively.Conclusion:MIS-TLIF has similar instrumentation-related complications with open TLIF.Accurate preoperative evaluation and improved surgical techniques can effectively reduce these instrumentation-related complications.

Comparison of simple discectomy and instrumented posterior lumbar interbody fusion for treatment of lumbar disc herniation combined with Modic endplate changes

Background The purpose of this retrospective study was to compare the surgical outcomes of simple discectomy and instrumented posterior lumbar interbody fusion （iPLIF） in patients with lumbar disc herniation and Modic endplate changes.Our hypothesis was that iPLIF could provide better outcome for patients with refractory lumbar disc herniation and Modic changes （LDH-MC）.Methods Ninety-one patients with single-segment LDH-MC were recruited.All patients experienced low back pain as well as radicular leg pain,and low back pain was more severe than leg pain.Forty-seven patients were treated with discectomy and 44 were treated with iPLIE The outcomes of both low back pain and radicular leg pain using visual analogue scale （VAS） as well as the clinical outcome related to low back pain using Japanese Orthopaedic Association （JOA） score were assessed before and 18 months after surgery,respectively.Results Both low back and leg pain were significantly improved 18 months after simple discectomy and iPLIE Compared to patients undergoing simple discectomy,low back pain was significantly reduced in patients undergoing iPLIE but there was no significant difference in leg pain between two groups.Solid fusion was achieved in all patients who underwent iPLIF.Conclusions In patients with LDH-MC,iPLIF can yield significantly superior outcome on the relief of low back pain compared to simple discectomy.Simple discectomy can relieve radicular leg pain as efficient as iPLIE Accordingly,iPLIF seems to be a reliable treatment for patients with LDH-MC and predominant low back pain.