Clinical and radiographic outcomes of bilateral decompression via a unilateral approach with transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis with stenosis

Biomechanical assessment of different transforaminal lumbar interbody fusion constructs in normal and osteoporotic condition: a finite element analysis

BACKGROUND CONTEXT

With the aging population, osteoporosis, which leads to poor fusion, has become a common challenge for lumbar surgery. In addition, most people with osteoporosis are elderly individuals with poor surgical tolerance, and poor bone quality can also weaken the stability of internal fixation.

PURPOSE

This study compared the fixation strength of the bilateral traditional trajectory screw structure (TT-TT), the bilateral cortical bone trajectory screw structure (CBT-CBT), and the hybrid CBT-TT (CBT screws at the cranial level and TT screws at the caudal level) structure under different bone mineral density conditions.

STUDY DESIGN

A finite element (FE) analysis study.

METHODS

Above all, we established a healthy adult lumbar spine model. Second, under normal and osteoporotic conditions, three transforaminal lumbar interbody fusion (TLIF) models were established: bilateral traditional trajectory (TT-TT) screw fixation, bilateral cortical bone trajectory (CBT-CBT) screw fixation, and hybrid cortical bone trajectory screw and traditional trajectory screw (CBT-TT) fixation. Finally, a 500-N compression load with a torque of 10 N/m was applied to simulate flexion, extension, lateral bending, and axial rotation. We compared the range of motion (ROM), adjacent disc stress, cage stress, and posterior fixation stress of the different fusion models.

RESULTS

Under different bone mineral density conditions, the range of motion of the fusion segment was significantly reduced. Compared to normal bone conditions, the ROM of the L4-L5 segment, the stress of the adjacent intervertebral disc, the surface stress of the cage, and the maximum stress of the posterior fixation system were all increased in osteoporosis. Under most loads, the ROM and surface stress of the cage and the maximum stress of the posterior fixation system of the TT-TT structure are the lowest under normal bone mineral density conditions. However, under osteoporotic conditions, the fixation strength of the CBT-CBT and CBT-TT structures are higher than that of the TT-TT structures under certain load conditions. At the same time, the surface stress of the intervertebral fusion cage and the maximum stress of the posterior fixation system for the two structures are lower than those of the TT-TT structure.

CONCLUSION

Under normal bone mineral density conditions, transforaminal lumbar interbody fusion combined with TT-TT fixation provides the best biomechanictability. However, under osteoporotic conditions, CBT-CBT and CBT-TT structures have higher fixed strength compared to TT-TT structures. The hybrid CBT-TT structure exhibits advantages in minimal trauma and fixation strength. Therefore, this seems to be an alternative fixation method for patients with osteoporosis and degenerative spinal diseases.

CLINICAL SIGNIFICANCE

This study provides biomechanical support for the clinical application of hybrid CBT-TT structure for osteoporotic patients undergoing TLIF surgery.

Comparison between minimally invasive and open transforaminal lumbar interbody fusion for the treatment of multi‑segmental lumbar degenerative disease: A systematic evaluation and meta‑analysis

The present study aimed to compare the differences between minimally invasive transforaminal lumbar fusion (MIS-TLIF) and open transforaminal lumbar fusion (TLIF) for multi-segmental lumbar degenerative disease regarding intraoperative indices and postoperative outcomes. PubMed, Web of Science, Embase, CNKI, Wanfang and VIP databases were searched for literature on MIS-TLIF and open TLIF in treating multi-segmental lumbar degenerative diseases. Of the 1,608 articles retrieved, 10 were included for final analysis. The Newcastle-Ottawa Scale and Review Manager 5.4 were used for quality evaluation and data analysis, respectively. The MIS-TLIF group was superior to the open TLIF group regarding intraoperative blood loss [95% confidence interval (CI): -254.33,-157.86; P<0.00001], postoperative in-bed time (95%CI: -3.49,-2.76; P<0.00001), hospitalization time (95%CI: -5.14,-1.78; P<0.0001) and postoperative leg pain Visual Analog Scale score (95%CI: -0.27,-0.13; P<0.00001). The fluoroscopy frequency for MIS-TLIF (95%CI: 2.07,6.12; P<0.0001) was significantly higher than that for open TLIF. The two groups had no significant differences in operation time, postoperative drainage volume, postoperative complications, fusion rate, or Oswestry Disability Index score. In treating multi-segmental lumbar degenerative diseases, MIS-TLIF has the advantages of less blood loss, shorter bedtime and hospitalization time and improved early postoperative efficacy; however, open TLIF has a lower fluoroscopy frequency.

Short-term and mid-term evaluation of three types of minimally invasive lumbar fusion surgery for treatment of L4/L5 degenerative spondylolisthesis

This was a single-centre retrospective study. Minimally invasive techniques for transforaminal lumbar interbody fusion (MIS-TLIF), oblique lumbar interbody fusion (OLIF), and percutaneous endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) have been extensively used for lumbar degenerative diseases. The present study analyses the short-term and mid-term clinical effects of the above three minimally invasive techniques on L4/L5 degenerative spondylolisthesis. In this retrospective study, 98 patients with L4/L5 degenerative spondylolisthesis received MIS-TLIF, 107 received OLIF, and 114 received Endo-TLIF. All patients were followed up for at least one year. We compared patient data, including age, sex, body mass index (BMI), Oswestry disability index (ODI), visual analogue scale of low back pain (VAS-B), visual analogue scale of leg pain (VAS-L), surgical time, blood loss, drainage volume, hospital stay, complications, and neurological status. Moreover, we performed imaging evaluations, including lumbar lordosis angle (LLA), disc height (DH) and intervertebral fusion status. No significant differences were noted in age, sex, BMI, preoperative ODI, preoperative VAS-B, preoperative VAS-L, preoperative LLA, or preoperative DH. Patients who underwent OLIF had significantly decreased blood loss, a lower drainage volume, and a shorter hospital stay than those who underwent MIS-TLIF or Endo-TLIF (P < 0.05). The VAS-B in the OLIF group significantly decreased compared with in the MIS-TLIF and Endo-TLIF groups at 6 and 12 months postoperatively (P < 0.05). The VAS-L in the Endo-TLIF group significantly decreased compared with that in the MIS-TLIF and OLIF groups at 6 months postoperatively (P < 0.05). The ODI in the OLIF group was significantly better than that in the MIS-TLIF and Endo-TLIF groups at 6 months postoperatively (P < 0.05). No statistically significant differences in the incidence of complications and healthcare cost were found among the three groups. Follow-up LLA and DH changes were significantly lower in the OLIF group than in the other groups (P < 0.05). The intervertebral fusion rate was significantly higher in the OLIF group than in the other groups at 6 and 12 months postoperatively (P < 0.05). In conclusion, while MIS-TLIF, OLIF, and Endo-TLIF techniques can effectively treat patients with L4/5 degenerative spondylolisthesis, OLIF has more benefits, including less operative blood loss, a shorter hospital stay, a smaller drainage volume, efficacy for back pain, effective maintenance of lumbar lordosis angle and disc height, and a higher fusion rate. OLIF should be the preferred surgical treatment for patients with L4/5 degenerative spondylolisthesis.

Comparison of minimally invasive transforaminal lumbar interbody fusion (Mis-TLIF) with bilateral decompression via unilateral approach and open-TLIF with bilateral decompression for degenerative lumbar diseases: a retrospective cohort study

OBJECTIVE

Presently, no study has compared the clinical outcomes of minimally invasive transforaminal lumbar interbody fusion (Mis-TLIF) with bilateral decompression via the unilateral approach (BDUA) and Open-TLIF with bilateral decompression for degenerative lumbar diseases (DLD). We aimed to compare the clinical outcomes of through Mis-TLIF combined with BDUA and Open-TLIF with bilateral decompression for the treatment of DLD, and reported the learning curve of the procedure of MIS-TLIF with BDUA.

METHODS

We retrospectively analyzed the prospectively collected data of consecutive DLD patients in the two groups from January 2016 to January 2020.

RESULTS

The operative time (OT) was significantly longer in the Mis-TLIF group (n = 113) than in the Open-TLIF group (n = 135). The postoperative drainage volume (PDV) and length of stay (LOS) were significantly higher in the Open-TLIF group than in the Mis-TLIF group. Additionally, the complication rate was significantly higher in the Open-TLIF group than in the Mis-TLIF group (14.8% vs. 6.2%, P = 0.030), while there was no significant difference in the reoperation and adjacent segment disease rates between the two groups. There were no significant differences in back pain and leg pain Numerical Rating Scale (NRS) scores and Oswestry Disability Index (ODI) between the two groups preoperatively, at discharge, and 2 years postoperatively. Patients in both groups showed significant improvements in NRS scores and ODI scores after surgery. OT was negatively correlated with the number of surgeries performed (P < 0.001, r =  -0.43). The learning curve of Mis-TLIF with BDUA was steep, with OT tapered to steady state in 43 cases.

CONCLUSION

Compared with Open-TLIF with bilateral decompression, Mis-TLIF with BDUA can achieve equivalent clinical outcomes, lower PDV and LOS, and lower complication rates. Although this procedure took longer, it could be a viable alternative for the treatment of DLD after a steep learning curve.

Novel approach of ultrasound-guided lateral recess block for a patient with lateral recess stenosis: A case report

BACKGROUND

Ultrasound guide technology, which can provide real-time visualization of the needle tip and tissues and avoid many adverse events, is widely used in minimally invasive therapy. However, the studies on ultrasound-guided Lateral recess block (LRB) are limited, this is probably because there is no recognized standard method for ultrasound scanning. This study aimed to evaluate the effect of ultrasound-guided LRB in patients with lateral recess stenosis (LRS).

CASE SUMMARY

A 65-year-old patient complained of low back pain accompanied occasionally by pain and numbness in the left lower limb. Physical examination showed tenderness on the spinous process and paraspinal muscles from L1 to S1, extensor hallucis longus and tibialis anterior weakness (muscle strength: 4-), and a positive straight leg raising test in the left lower limb (60°). Magnetic resonance imaging showed L4-L5 disc degeneration with left LRS and nerve root entrapment. Subsequently, the patient was diagnosed with LRS. This patient was treated with a novel ultrasound-guided LRB approach. The patient's symptoms significantly improved without any complications at 1 wk postoperatively and at the 3-month follow-up.

CONCLUSION

This is the first report on the LRS treatment with ultrasound-guided LRB from the contralateral spinous process along the inner side of the articular process by out-plane technique. Further studies are expected to investigate the efficacy and safety of ultrasound-guided LRB for patients with LRS.

Novel Use of Bilateral Prone Transpsoas Approach for the Treatment of Transforaminal Interbody Fusion Pseudarthrosis and Interbody Cage Subsidence

BACKGROUND AND OBJECTIVES

Pseudarthrosis is a complication after transforaminal lumbar interbody fusion (TLIF) that leads to recurrent symptoms and potential revision surgery. Subsidence of the interbody adds to the complexity of surgical revision. In addition, we report a novel technique for the treatment of TLIF pseudarthrosis with subsidence and propose an approach algorithm for TLIF cage removal.

METHODS

Cases of reoperation for TLIF pseudarthrosis were reviewed. We report a novel technique using a bilateral prone transpsoas (PTP) approach to remove a subsided TLIF cage and place a new lateral cage. An approach algorithm was developed based on the experience of TLIF cage removal. The patient was placed in the prone position with somatosensory evoked potential and electromyography monitoring. A PTP retractor was placed using standard techniques on the ipsilateral side of the previous TLIF. After the discectomy, the subsided TLIF cage was visualized but unable to be removed. The initial dilator was closed, and a second PTP retractor was placed on the contralateral side. After annulotomy and discectomy to circumferentially isolate the subsided cage, a box cutter was used to push and mobilize the TLIF cage from this contralateral side, which could then be pulled out from the ipsilateral side. A standard lateral interbody cage was then placed.

RESULTS

Retractor time was less than 10 minutes on each side. The patient's symptoms resolved postoperatively. We review illustrative cases of various approaches for TLIF cage removal spanning the lumbosacral spine and recommend an operative approach based on the lumbar level, degree of subsidence, and mobility of the interbody.

CONCLUSION

Bilateral PTP retractors for TLIF cage removal may be effectively used in cases of pseudarthrosis with severe cage subsidence. Careful consideration of various factors, including patient surgical history, body habitus, and intraoperative findings, is essential in determining the appropriate treatment for these complex cases.

Comparison of safety and efficacy of posterior lumbar interbody fusion (PLIF) and modified transforaminal lumbar interbody fusion (M-TLIF) in the treatment of single-segment lumbar degenerative diseases

OBJECTIVE

To compare modified transforaminal lumbar interbody fusion (M-TLIF) with posterior lumbar interbody fusion (PLIF) in the treatment of single-segment lumbar degenerative disorders in order to assess its safety and effectiveness.

METHODS

From January 2016 to January 2021, 74 patients who received single-segment M-TLIF were examined. A total of 74 patients having single-segment PLIF during the same time period were included in a retrospective controlled study using the same inclusion and exclusion criteria. The two groups were compared in terms of the fusion rate, the Oswestry disability index (ODI), the visual analogue scale of low back pain (VAS), the perioperative condition, the postoperative complications, and the postoperative neighbouring segment degeneration.

RESULTS

All patients had surgery satisfactorily and were monitored for at least a year afterwards. The baseline values for the two groups did not significantly differ. The interbody fusion rate between PLIF (98.65%) and M-TLIF (97.30%) was not significantly different. In the follow-up, the M-TLIF group's VAS score for low back and leg pain was lower than that of the PLIF group. The ODI score of the M-TLIF group was lower than that of the PLIF group at 7 days and 3 months following surgery. Both groups' post-op VAS and ODI scores for low back and leg pain were much lower than those from before the procedure. In M-TLIF group, the operation time, drainage tube extraction time, postoperative bed rest time and hospital stay time were shorter, and the amount of intraoperative blood loss was less. Compared with those before operation, the height of intervertebral space and intervertebral foramen were significantly increased in both groups during postoperative follow-up (P < 0.05). The postoperative complications and adjacent segment degeneration of M-TLIF were significantly lower than those of PLIF.

CONCLUSIONS

M-TLIF is a safe and effective treatment for lumbar degenerative disorders, with a high fusion rate and no significant difference between M-TLIF and PLIF. M-TLIF's efficacy and safety are comparable to that of PLIF, particularly in terms of early relief of low back pain and improvement in quality of life following surgery. Therefore, M-TLIF technology can be popularized and applied in clinic.

Clinical efficacy of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of II° lumbar isthmic spondylolisthesis: A retrospective cohort study

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is not suitable for high-grade isthmic spondylolisthesis, whether MIS-TLIF can treat II° lumbar isthmic spondylolisthesis (IS) is still controversial. This retrospective cohort study compared the clinical efficacy of MIS-TLIF and open transforaminal lumbar interbody fusion (OPEN-TLIF) in the treatment of II° lumbar IS. From January 2017 to January 2023, 101 patients with II° lumbar IS were diagnosed in our hospital and underwent surgical treatment, of which 53 received MIS-TLIF surgery and 48 received OPEN-TLIF surgery. The operation time, blood loss and surgical complications were compared between the 2 groups. The pain, function, reduction rate and fusion rate of the patients were evaluated during follow-up. The amount of intraoperative blood loss, postoperative drainage, and postoperative hospital stay in the MIS-TLIF group were significantly lower than those in the OPEN-TLIF group were (P < .01). In the MIS-TLIF group, there were 1 case of dural sac injury and 3 cases of lower limb paralysis. The complication rate of MIS-TLIF was lower than the OPEN-TLIF group (P = .032). In the visual analog scale score of low back pain, the MIS-TLIF group was lower than the OPEN-TLIF group after operation and at the last follow-up. There were no significant differences in postoperative leg pain score, slippage rate, and fusion rate between the 2 groups. Compared with OPEN-TLIF, MIS-TLIF has the advantages of better low back pain relief, less trauma, less bleeding and faster recovery, and is worthy of clinical promotion.

The effect of the cortical bone trajectory screw fixation and traditional pedicle screw fixation on surgical site wound infection in posterior lumbar fusion wound: A meta-analysis

A meta-analysis investigation was performed to measure the influence of cortical bone trajectory screw fixation (CBTSF) and traditional pedicle screw fixation (TPSF) on surgical site wound infection (SSWI) in posterior lumbar fusion (PLF). A comprehensive literature inspection till February 2023 was applied and 1657 interrelated investigations were reviewed. The 13 chosen investigations enclosed 1195 individuals with PLF in the chosen investigations' starting point, 578 of them were using CBTSF, and 617 were using TPSF. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were utilised to compute the value of the effect of the CBTSF and TPSF on SSWI in PLF by the dichotomous approaches and a fixed or random model. No significant difference was found between individuals using CBTSF and TPSF in SSWI (OR, 0.68; 95% CI, 0.35-1.33, P = .26), superficial SSWI (OR, 0.62; 95% CI, 0.22-1.79, P = .38), and deep SSWI (OR, 0.30; 95% CI, 0.06-1.50, P = .14) in PLF. No significant difference was found between individuals using CBTSF and TPSF in SSWI, superficial SSWI, and deep SSWI in PLF. However, care must be exercised when dealing with its values because of the small sample sizes of several chosen investigations for this meta-analysis and the low number of selected investigations for a certain type of SSWI.

Establishment of an animal model of adjacent segment degeneration after interbody fusion and related experimental studies

BACKGROUND

Degenerative spine conditions are common and frequent clinical diseases, and adjacent segment disease (ASD) after spinal fusion (SF) is a common complication after spinal fusion (SF). In this study, we established an animal model of ASD after interbody fusion to observe the morphologic changes of adjacent segment (AS) disks and to determine the expression and significance of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) in ASD tissues to provide a good experimental basis and reference for clinical prevention and treatment of ASD after interbody fusion.

METHODS

Thirty-six male and female New Zealand rabbits weighing 2.0-2.5 kg were randomly divided into control group (group A) and experimental groups (groups B, C, and D), with 9 rabbits in each group, of which groups B, C, and D were the 4-, 8-, and 12-week groups, respectively. Autologous iliac bone grafts were used as the bone graft material. In the experimental groups, a SF was performed on the C2-C3 intervertebral space. The C3-4 adjacent segments were examined. In the experimental group, the animals were subjected to gross observation, X-ray examination, hand touch inspection, and micro-computed tomography (micro-CT) 4, 8, and 12 weeks after surgery. The micromorphologic changes of the cervical disks in the segments of the control group and experimental groups were observed under light microscopy. Immunohistochemistry and Western blotting were used to detect the expression of TNF-α and IL-1β in the AS tissues after interbody fusion in the control and experimental groups.

RESULTS

The measurement data of the rabbit cervical spine bony structures indicated that the length of the vertebral body and the sagittal diameter of the lower end of the vertebral body decreased gradually from the 2nd-6th cervical vertebrae, and the difference was statistically significant (P < 0.05). The difference in the transverse diameter of the lower end of the vertebral body was not statistically significant (P > 0.05), the change in the oblique diameter of the lower end of the vertebral body fluctuated, and the difference was statistically significant (P < 0.05). The fusion rate of the cervical spine by hand touch inspection was 22.2% (2/9), 55.6% (5/9), and 88.9% (8/9) in groups B, C, and D, respectively. The differences in bone volume-to-total volume (BV/TV) and X-ray scores were statistically significant in groups B, C, and D (P < 0.05). Significant degeneration occurred in groups B, C, and D compared with group A. The expression of TNF-α and IL-1β in the intervertebral disk tissue was significantly higher in groups B, C, and D compared with group A (P < 0.05), and increased with time.

CONCLUSION

In this study, an animal model of ASD after interbody fusion fixation in rabbits was successfully established. Postoperative imaging and hand touch inspection showed a positive correlation between the amount of new intervertebral bone and the degree of fusion with time. The results of immunohistochemistry and Western blot showed that TNF-α and IL-1β were highly expressed in the AS tissues of the experimental group after interbody fusion, and the degree of disk degeneration was positively correlated with the time after interbody fusion.

Unilateral Modified Posterior Lumbar Interbody Fusion Combined With Contralateral Lamina Fenestration Treating Severe Lumbarspinal Stenosis: A Retrospective Clinical Study

Study design: Retrospective study. Objectives: The traditional PLIF is routinely utilized in severe lumbar spinal stenosis to relief the nerve compression. Nevertheless, the removal of posterior tension-band structure and the denervation and atrophy of the paraspinal muscle affect the clinical efficacy. Therefore, unilateral modified PLIF combined with contralateral fenestration was performed to overcome above-mentioned drawbacks. Methods: 32 modified PLIF and 33 traditional PLIF cases were retrospectively included. Operation time, length of stay (LOS) and blood loss were recorded. VAS of low back pain and leg pain, ODI and Sf-36 score including physical function and body pain were assessed. Fusion rate, lumbar lordosis (LL), intervertebral angle (IVA) and intervertebral height index (IHI) were evaluated radiologically. Results: Modified group possessed less blood loss, shorter operation time and less LOS. Compared with traditional group, the VAS of back pain was lower at 6 months postoperatively (P < .05) and the ODI score was lower at 3 months postoperatively (P < .05) in modified group. Modified group exhibited better physical function 3 months postoperatively and lower body pain 6 months postoperatively in Sf-36 score (P < .05). No statistic difference in LL, IVA, IHI and fusion rate were observed between both groups. Conclusions: Our modified PLIF combining with contralateral fenestration procedure exhibited particular advantages in comparison to traditional PLIF. The preservation of posterior tension-band structure facilitates to less low back pain, low complication rate and early functional recovery.

Cortical Trajectory Fixation Versus Traditional Pedicle-Screw Fixation in the Treatment of Lumbar Degenerative Patients with Osteoporosis: A Prospective Randomized Controlled Trial

Study Design

Objective

Methods

Results

Conclusion

Trial Registration Number

Date of Registration

[Degenerative lumbar spine stenosis: minimally invasive microsurgical methods of treatment]

Degenerative lumbar spine stenosis is one of the main causes of chronic pain and radiculopathy in advanced age people. Along with increase in average life expectancy, degenerative lumbar spine stenosis becomes the most common indication for spinal surgery. There is still no consensus regarding the most optimal surgical approach due to the variety of modern surgical methods. In recent years, minimally invasive spinal surgery has become a more advisable alternative to open surgery due to its advanced technical features combined with less soft tissue damage, lower risk of complications and shorter postoperative recovery.

A Prospective Randomized Study of the Safety and Efficacy of Transforaminal Lumbar Interbody Fusion Versus Posterior Lumbar Interbody Fusion in the Treatment of Lumbar Spondylolisthesis: A Cost utility from a Lower-middle-income Country Perspective and Review of Literature

BACKGROUND: The safety and efficacy of transforaminal lumbar interbody fusion (TLIF) and posterior lumbar interbody fusion (PLIF) in lumbar spondylolisthesis have not been validated in many prospective randomized trials. AIM: We aimed to validate the safety and efficacy of TLIF and PLIF surgery in lumbar spondylolisthesis using the clinical, radiographic, and cost-utility outcomes. METHODS: The data of surgically treated single-level spondylolisthesis patients were randomized prospectively into two groups. The groups were compared regarding demographics, perioperative complications, hospital stay, total expenditure, fusion rate, and clinical outcomes (visual analog scale, Oswestry disability index, Zurich claudication scale, and Odom’s criteria). A review of literature was done to compare the outcomes with the ones from higher-income nations. RESULTS: Thirty-three patients underwent prospective randomization. The improvement in the clinical outcomes at 12-month follow-up showed improvement in the TLIF group more than the PLIF group but with no significant difference. The mean operative time was significantly longer in the PLIF (p < 0.05), also, the blood loss was significantly less in the TLIF (p < 0.001). The complications frequency did not show any statistical significance between both groups and no significant difference in the patient’s post-operative patient satisfaction (p = 0.6). The mean hospital stay was non-significantly longer in the PLIF (p = 0.7). At 12-month follow-up, 93.3% of the TLIF patients were fused versus 86.7% of the PLIF (p = 0.5). The total cost of the TLIF was significantly less (p < 0.001). CONCLUSION: Both PLIF and TLIF could achieve similar fusion rates and clinical satisfaction in the management of lumbar spondylolisthesis. The TLIF group was significantly better in terms of financial burden, operative time, and blood loss.

Safety of Lumbar Interbody Fusion Procedures for Degenerative Disc Disease: A Systematic Review With Network Meta-Analysis of Prospective Studies

STUDY DESIGN

A network meta-analysis.

OBJECTIVES

Lumbar degenerative disc disease (LDDD) is an important issue in aging population, for which lumbar interbody fusion (LIF) is a feasible management in cases refractory to conservative therapy. There are various techniques available to perform LIF, including posterior (PLIF), transforaminal (TLIF), and anterior (ALIF) approaches. However, the comparative safety profile of these procedures remains controversial. Our study aimed to evaluate comparative adverse events of the LIF procedures in patients with LDDD.

METHODS

We searched 5 databases for relevant prospective cohort studies and randomized clinical trials. After quality assessments, we extracted neural, spinal, vascular, and wound events for conducting contrast-based network meta-analysis. Results were reported in risk ratio (RR), 95% confidence interval (CI), and surface under the cumulative ranking (SUCRA).

RESULTS

We identified 14 studies involving 921 participants with LDDD. Pooled result showed that open PLIF (OPLIF) leads to significantly higher overall adverse event rate than does open TLIF (OTLIF; RR = 3.43, 95% CI = 1.21-9.73). OTLIF confers the highest SUCRA in neural (78.7) and spinal (80.8) event rates. Minimally invasive TLIF has the highest SUCRA in vascular event (84.2), and minimally invasive PLIF has the highest SUCRA in wound event (88.1). No inconsistency or publication bias was detected in the results.

CONCLUSIONS

Based on our results, perhaps OPLIF should be avoided in the management of LDDD due to the inferiority of overall complications. Specifically, TLIF seems to have the safest profile in terms of neural, spinal, and vascular events. Nevertheless, shared decision making is still mandatory when choosing the proper LIF procedure for patients with LDDD in clinical practice.

Oblique Lateral Interbody Fusion versus Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spondylolisthesis: A Single-Center Retrospective Comparative Study

Objective

To compare the efficacy of oblique lateral interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in single-level degenerative lumbar spondylolisthesis (DLS).

Methods

A retrospective analysis of patients who underwent single-level DLS surgery in our department from 2015 to 2018 was performed. According to the surgical method, the enrolled patients were divided into two groups, namely, the OLIF group who underwent OLIF combined with percutaneous pedicle screw fixation (PPSF) and the TLIF group. Clinical outcomes included operation time, operation blood loss, postoperative drainage, hospital stay, visual analog scale (VAS) score, Oswestry disability index (ODI), and complications, and imaging outcomes included upper vertebral slip, intervertebral space height (ISH), intervertebral foramen height (IFH), intervertebral space angle (ISA), lumbar lordosis (LL), and bone fusion rate. All outcomes were recorded and analyzed.

Results

A total of 65 patients were finally included, and there were 28 patients and 37 patients in the OLIF group and the TLIF group, respectively. The OLIF group showed shorter operation time, less blood loss, less postoperative drainage, and shorter hospital stay than the TLIF group (P < 0.05). The ISH, IFH, ISA, and LL were all larger in the OLIF group at postoperative and last follow-up (P < 0.05), but the degree of upper vertebral slip was found no difference between the two groups (P > 0.05). The bone graft fusion rate of OLIF group and TLIF group at 3 months, 6 months, and last follow-up was 78.57%, 92.86%, and 100% and 70.27%, 86.49%, and 97.30%, respectively, and no significant differences were found (P > 0.05). Compared with the TLIF group, the OLIF group showed a superior improvement in VAS and ODI at 1 month, 3 months, and 6 months postoperative (P < 0.05), but no differences were found at 12 months postoperative and the last follow-up (P > 0.05). There was no significant difference in complications between the two groups, with 4 patients and 6 patients in the OLIF group and TLIF group, respectively (P > 0.05).

Conclusions

Compared with TLIF, OLIF showed the advantages of less surgical invasion, better decompression effect, and faster postoperative recovery in single-level DLS surgery.

Evaluation of the Minimum Clinically Important Differences of the Zurich Claudication Questionnaire in Patients With Lumbar Spinal Stenosis

STUDY DESIGN

A case-control study.

OBJECT

This study aimed to evaluate the minimally clinically important differences (MCIDs) of the Zurich Claudication Questionnaire (ZCQ) after microendoscopic laminectomy in patients with lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

The ZCQ is a self-administered tool used to evaluate symptom severity and physical function in patients with LSS. It has been used in many studies worldwide. However, the MCIDs of the ZCQ have not yet been determined.

MATERIALS AND METHODS

The study sample consisted of 514 patients who underwent microendoscopic laminectomy for LSS at our hospital between March 2012 and May 2014. The ZCQ, which includes 7 items for symptom severity (scored from 1 to 5) and 5 items for functional disability (scored from 1 to 4), was administered preoperatively and 1-year postoperatively. The MCID was calculated by 4 approaches, including average change, minimum detectable change, change difference, and receiver operating characteristic curve. The authors calculated the area under the curve (AUC) to evaluate the accuracy of the receiver operating characteristic curve. The responsiveness of each measurement was then analyzed.

RESULTS

The authors were able to administer the ZCQ at 1-year postoperatively in 349 patients. The ZCQ score was statistically significantly improved 1-year postoperatively. The MCID of ZCQ for symptom severity varied from 0.75 to 0.84, whereas the MCID of the ZCQ score for functional disability varied from 0.60 to 0.76. The AUC of the ZCQ for symptom severity was 0.81 and that for functional disability was 0.80.

CONCLUSIONS

This study showed that the MCID of the ZCQ for symptom severity varied from 0.75 to 0.84 and the MCID for functional disability varied from 0.60 to 0.76. In addition, each AUC was over 0.80, indicating that MCIDs of the ZCQ were found to have a high diagnostic performance.

[Comparative study on effectiveness of modified-transforaminal lumbar interbody fusion and posterior lumbar interbody fusion surgery in treatment of mild to moderate lumbar spondylolisthesis in middle-aged and elderly patients]

OBJECTIVE

To compare the effectiveness of modified transforaminal lumbar interbody fusion (modified-TLIF) and posterior lumbar interbody fusion (PLIF) for mild to moderate lumbar spondylolisthesis in middle-aged and elderly patients.

METHODS

The clinical data of 106 patients with mild to moderate lumbar spondylolisthesis (Meyerding classification≤Ⅱ degree) who met the selection criteria between January 2015 and January 2017 were retrospectively analysed. All patients were divided into modified-TLIF group (54 cases) and PLIF group (52 cases) according to the different surgical methods. There was no significant difference in preoperative clinical data of gender, age, disease duration, sliding vertebra, Meyerding grade, and slippage type between the two groups ( P>0.05). The intraoperative blood loss, operation time, postoperative drainage volume, postoperative bed time, hospital stay, and complications of the two groups were recorded and compared. The improvement of pain and function were evaluated by the visual analogue scale (VAS) score and Japanese Orthopedic Association (JOA) score at preoperation, 1 week, and 1, 6, 12 months after operation, and last follow-up, respectively. The effect of slip correction was evaluated by slip angle and intervertebral altitude at preoperation and last follow-up, and the effectiveness of fusion was evaluated according to Suk criteria.

RESULTS

All patients were followed up, the modified-TLIF group was followed up 25-36 months (mean, 32.7 months), the PLIF group was followed up 24-38 months (mean, 33.3 months). The intraoperative blood loss, operation time, postoperative drainage volume, postoperative bed time, and hospital stay of the modified-TLIF group were significantly less than those of the PLIF group ( P<0.05). The VAS score and JOA score of both groups were significantly improved at each time point after operation ( P<0.05); the scores of the modified-TLIF group were significantly better than those of the PLIF group at 1 and 6 months after operation ( P<0.05). The slip angle and intervertebral altitude of both groups were obviously improved at last follow-up ( P<0.05), and there was no significant difference between the two groups at preoperation and last follow-up ( P>0.05). At last follow-up, the fusion rate of the modified-TLIF group and the PLIF group was 96.3% (52/54) and 98.1% (51/52), respectively, and no significant difference was found between the two groups ( χ 2=0.000, P=1.000). About complications, there was no significant difference between the two groups in nerve injury on the opposite side within a week, incision infection, and pulmonary infection ( P>0.05). No case of nerve injury on the operation side within a week or dural laceration occurred in the modified-TLIF group, while 8 cases (15.4%, P=0.002) and 4 cases (7.7%, P=0.054) occurred in the PLIF group respectively.

CONCLUSION

Modified-TLIF and PLIF are effective in the treatment of mild to moderate lumbar spondylolisthesis in middle-aged and elderly patients. However, modified-TLIF has relatively less trauma, lower blood loss, lower drainage volume, lower incidence of dural laceration and nerve injury, which promotes enhanced recovery after surgery.

A modified procedure of single-level transforaminal lumbar interbody fusion reduces immediate post-operative symptoms: a prospective case-controlled study based on two hundred and four cases

STUDY DESIGN

This is a prospective case-controlled study.

PURPOSE

The purpose of this study is to investigate the effect of a modified transforaminal lumbar interbody fusion (TLIF) on the immediate post-operative symptoms in patients with lumbar disc herniation (LDH) accompanied with stenosis.

METHODS

A total of 204 LDH patients with single-level TLIF were enrolled. According to the sequence of the placement of rods and cage, patients were divided into group R (rod-prior-to-cage) and group C (cage-prior-to-rod). Neurological function was evaluated by the Japanese Orthopedic Association (JOA) score. Radiological assessment includes height of intervertebral space (HIS), foraminal height (FH), foraminal area (FA), and segmental lordosis (SL). Change of original symptoms (pain/numb) and new-onset symptoms (pain/numb) after surgery were also recorded.

RESULTS

Patients in group R had less change of HIS at L3/4, L4/5, and L5/S1 levels compared with pre-operation (all p > 0.05), whereas group C had larger change (all p < 0.05). No statistical difference was found in FH between the two groups before and after surgery at L3/4, L4/5, and L5/S1, respectively (all p > 0.05). In terms of FA, patients in group R had better improvement after surgery than those in group C at L3/4 and L4/5 (both p < 0.05). Patients in both groups acquired good improvement of neurological function. However, there were fewer patients in group R who experienced post-operative leg pain or numb compared with those in group C (p < 0.05).

CONCLUSION

The modified open TLIF can significantly reduce the incidence of immediate post-operative symptoms for patients with single-level lumbar disc herniation via installation of rods prior to insertion of cage and the "neural standard" should serve as the goal of decompression for spine surgeons to restore disc/foraminal height and to minimize nerve distraction.

Assessment of radiographic and clinical outcomes of an articulating expandable interbody cage in minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis

OBJECTIVE The inability to significantly improve sagittal parameters has been a limitation of minimally invasive surgery for transforaminal lumbar interbody fusion (MIS TLIF). Traditional cages have a limited capacity to restore lordosis. This study evaluates the use of a crescent-shaped articulating expandable cage (Altera) for MIS TLIF. METHODS This is a retrospective review of 1- and 2-level MIS TLIF. Radiographic outcomes included differences in segmental and lumbar lordosis, disc height, evidence of fusion, and any endplate violations. Clinical outcomes included the numeric rating scale for leg and back pain and the Oswestry Disability Index (ODI) for low-back pain. RESULTS Thirty-nine patients underwent single-level MIS TLIF, and 5 underwent 2-level MIS TLIF. The mean age was 63.1 years, with 64% women. On average, spondylolisthesis was corrected by 4.3 mm (preoperative = 6.69 mm, postoperative = 2.39 mm, p < 0.001), the segmental angle was improved by 4.94° (preoperative = 5.63°, postoperative = 10.58°, p < 0.001), and segmental height increased by 3.1 mm (preoperative = 5.09 mm, postoperative = 8.19 mm, p < 0.001). At 90 days after surgery the authors observed the following: a smaller postoperative sagittal vertical axis was associated with larger changes in back pain at 90 days (r = -0.558, p = 0.013); a larger decrease in spondylolisthesis was associated with greater improvements in ODI and back pain scores (r = -0.425, p = 0.043, and r = -0.43, p = 0.031, respectively); and a larger decrease in pelvic tilt (PT) was associated with greater improvements in back pain (r = -0.548, p = 0.043). For the 1-year PROs, the relationship between the change in PT and changes in ODI and numeric rating scale back pain were significant (r = 0.612, p = 0.009, and r = -0.803, p = 0.001, respectively) with larger decreases in PT associated with larger improvements in ODI and back pain. Overall for this study there was a 96% fusion rate. Fourteen patients were noted to have endplate violation on intraoperative fluoroscopy during placement of the cage. Only 3 of these had progression of their subsidence, with an overall subsidence rate of 6% (3 of 49) visible on postoperative CT. CONCLUSIONS The use of this expandable, articulating, lordotic, or hyperlordotic interbody cage for MIS TLIF provides a significant restoration of segmental height and segmental lordosis, with associated improvements in sagittal balance parameters. Patients treated with this technique had acceptable levels of fusion and significant reductions in pain and disability.

[Percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for lumbar spinal stenosis]

OBJECTIVE

To design the surgical strategy of percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for bilateral lumbar spinal stenosis (LSS) and to evaluate the effectiveness.

METHODS

The percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for bilateral LSS was designed according to the pathological features of LSS. The technique was used to treat 42 patients with LSS between January 2016 and January 2018. There were 18 males and 24 females with an average age of 61.7 years (range, 46-81 years). The duration of symptoms was 1-20 years, with an average of 9.7 years. The surgical segment at L 4, 5 were 27 cases, at L 5, S 1 were 15 cases. The operation time and perioperative complications were recorded. Lumbar X-ray, CT, and MRI examinations were performed at 1 week, 3 months, and 1 year after operation. Visual analogue scale (VAS) score was used to evaluate the low back pain and leg pain, Oswestry disability index (ODI) was used to evaluate the lumbar function, and single continuous walking distance (SCWD) was used to evaluate lower extremity nerve function. The clinical efficacy was evaluated by MacNab criteria at 1 year after operation.

RESULTS

All patients underwent surgery successfully. The operation time was 68-141 minutes with an average of 98.2 minutes. All 42 patients were followed up 12-24 months with an average of 18.8 months. There were 2 cases of dural tears during operation, and 1 case of transient dysfunction of the lower limbs of the decompression channel after operation. All of them were cured after corresponding treatment. No serious complications such as death, major bleeding, or irreversible nerve injury occurred during follow-up. No segmental instability was found according to postoperative lumbar hyperextension and flexion X-ray films, and postoperative CT and MRI imaging showed that the stenotic lumbar spinal canal was significantly enlarged, and the compression of the nerve root was sufficient. The VAS score of low back pain and leg pain, ODI score, and SCWD at each time point after operation were significantly improved when compared with those before operation ( P<0.05); the indexes were significantly improved over time after operation, and the differences were significantly ( P<0.05). The clinical efficacy was evaluated by MacNab standard at 1 year after operation, and the results were excellent in 18 cases, good in 20 cases, fair in 3 cases, and poor in 1 case. The excellent and good rate was 90.5%.

CONCLUSION

The percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for LSS is a safe and effective procedure. A well-designed surgical strategy and mastery of its technical points are important guarantees for successful operation and satisfactory results.

Cage positioning as a risk factor for posterior cage migration following transforaminal lumbar interbody fusion - an analysis of 953 cases

Background

The risk of posterior cage migration (PCM) exists when a fusion cage is used for transforaminal lumbar interbody fusion (TLIF). This complication is influenced by contact pressure between the endplate and the cage. Previous reports demonstrated that anteriorly located cages bore more load and had greater strain than posteriorly located cages. However, there have been no detailed reports on the correlation between cage positioning and PCM.

Methods

From March 2014 to October 2015, we reviewed 953 patients receiving open transforaminal lumbar interbody fusion (TLIF) and bilateral pedicle screw instrumentation. One hundred patients without PCM were randomly sampled as the control group. Postoperative sagittal and coronal cage positions in the disc space were evaluated with the ‘depth ratio’ and the ‘coronal ratio’. The demographic data of patients with and without PCM were compared to detect patient-related factors. Radiographic and cage related parameters, including cage position, preoperative disc height, preoperative spine stability, cage geometry, cage size, and height variance (= cage height – preoperative disc height) were compared between the PCM group and the control group. Univariate analyses and a multivariate logistic model were used to identify risk factors of PCM.

Results

Posterior cage migration occurred in 24 (2.52%) of 953 patients. The univariate and multivariate analyses revealed that those with a decreased depth ratio (OR, 9.78E-4; 95% CI, 9.69E-4 – 9.87E-4; p < 0.001) and height variance (OR, 0.757, 95% CI, 0.575–0997, p = 0.048) had a significantly higher risk of developing PCM.

Conclusions

Our results verified that posteriorly located cages and undersized cages are more prone to developing PCM, which may aid surgeons in making optimal decisions during TLIF procedures.

Correlation of 2-year SRS-22r and ODI patient-reported outcomes with 5-year patient-reported outcomes after complex spinal fusion: a 5-year single-institution study of 118 patients

OBJECTIVE

Patient-reported outcomes (PROs) are often measured up to 2 years after surgery; however, prospective collection of longitudinal outcomes for 5 years postoperatively can be challenging due to lack of patient follow-up. The aim of this study was to determine whether PROs collected at 2-year follow-up accurately predict long-term PROs 5 years after complex spinal fusion (≥ 5 levels).

METHODS

This was an ambispective study of 118 adult patients (≥ 18 years old) undergoing ≥ 5-level spinal arthrodesis to the sacrum with iliac fixation from January 2002 to December 2011. Patient demographics and radiographic parameters as well as intraoperative variables were collected. PRO instruments (Scoliosis Research Society [SRS]-22r function, self-image, mental health, pain, and Oswestry Disability Index [ODI]) were completed before surgery then at 2 and 5 years after surgery. Primary outcome investigated in this study was the correlation between SRS-22r domains and ODI collected at 2- and 5-year follow-up.

RESULTS

Of the 118 patients, 111 patients had baseline PROs, 105 patients had 2-year follow-up data, and 91 patients had 5-year follow-up PRO data with 72% undergoing revision surgery. The average pre- and postoperative major coronal curve Cobb angles for the cohort were 32.1° ± 23.7° and 19.8° ± 19.3°, respectively. There was a strong correlation between 2- and 5-year ODI (r2 = 0.80, p < 0.001) and between 2- and 5-year SRS-22r domains, including function (r2 = 0.79, p < 0.001), self-image (r2 = 0.82, p < 0.001), mental health (r2 = 0.77, p < 0.001), and pain (r2 = 0.79, p < 0.001). Of the PROs, ODI showed the greatest absolute change from baseline to 2- and 5-year follow-up (2-year Δ 17.6 ± 15.9; 5-year Δ 16.5 ± 19.9) followed by SRS-22r self-image (2-year Δ 1.4 ± 0.96; 5-year Δ 1.3 ± 1.0), pain (2-year Δ 0.94 ± 0.97; 5-year Δ 0.80 ± 1.0), function (2-year Δ 0.60 ± 0.62; 5-year Δ 0.49 ± 0.79), and mental health (2-year Δ 0.49 ± 0.77; 5-year Δ 0.38 ± 0.84).

CONCLUSIONS

Patient-reported outcomes collected at 2-year follow-up may accurately predict long-term PROs (5-year follow-up).

Optimal medial transforaminal lumbar interbody fusion approach with five extensive options: A simulated study on three-dimensional digital reconstructed images

Objective

The objective of this study is to use 3D digital lumbar models to investigate and simulate the optimal posterior operative approach for safe decompression and insertion of an interbody cage.

Methods

Thirty lumbar spine (L3-S1) computed tomography data are collected for 3D reconstruction. We cut medial half part of the superior facet and define the distance between the margin of the operative side of the spinous process and the medial margin of the cut superior facet as "medial distance (MD)". Then, we cut the total superior facet and define the distance between the margin of the operative side of the spinous process and the lateral side of the junction of the pedicle and the vertebral body as "extend distance (ED)". The feasible insertion of the current standard width size (10 mm and 12 mm) interbody cages was assessed by the two aforementioned MD and ED approaches. Besides the ED, we also simulate four other extensive options of lateral upper, lateral lower, vertical upper and lower and transmedian contralateral decompression on 3D digital lumbar model.

Results

The MD increased from 13.48 ± 1.28 mm at L3/4 to 18.05 ± 1.43 mm at L5/S1, and the ED increased from 16.64 ± 1.34 mm at L3/4 to 21.12 ± 1.62 mm at L5/S1. To insert a 10-mm-wide cage, 16.7% (left) and 13.3% (right) of MD for L3/4 is not enough, 60.0% (left) and 46.7% (right) of MD for L3/4 is subsafe, 13.3% (left) and 16.7% (right) of MD for L4/5 is subsafe and all others are safe. To insert a 12-mm-wide cage, 76.7% (left) and 60.0% (right) of MD for L3/4 is not enough, 20.0% (left) and 30.0% (right) of MD for L3/4 is subsafe, 13.3%% (left) and 16.7% (right) of MD for L4/5 is not enough, 63.3% (left) and 56.7% (right) of MD for L4/5 is subsafe and 6.7% (left) and 10.0% (right) of MD for L5/S1 is subsafe, whereas 33.3%% (left) and 30.0% (right) of ED for L3/4 is subsafe, 3.3% (left) and 3.3% (right) of ED for L4/5 is subsafe and all others are safe. Besides the ED, on 3D models, four other extensive options could be simulated too and may need to be performed for different special individuals.

Conclusion

Our 3D digital image study provides a feasible optimal medial transforaminal lumbar interbody fusion approach with five extensive options on lower lumbar region. It can provide safe lumbar decompression and interbody fusion in most population. In addition, surgeons can choose the different extensive options for special individual conditions.

The translational potential of this article

Transforminal lumbar interbody fusion is very common used for lumbar degenerative diseases. The optimal medial transforminal lumbar interbody fusion with five options provide a safe and precise approach for surgeons in treatment of lumbar degenerative diseases.

Treatment for Degenerative Lumbar Spondylolisthesis: Current Concepts and New Evidence

PURPOSE OF REVIEW

Current guidelines for the optimal treatment degenerative spondylolisthesis are weak and based on limited high-quality evidence.

RECENT FINDINGS

There is some moderate evidence that decompression alone may be a feasible treatment with lower surgical morbidity and similar outcomes to fusion when performed in a select population with a low-grade slip. Similarly, addition of interbody fusion may be best suited to a subset of patients with high-grade degenerative spondylolisthesis, although this remains controversial. Minimally invasive techniques are increasingly being utilized for both decompression and fusion surgeries with more and more studies showing similar outcomes and lower postoperative morbidity for patients. This will likely be an area of continued intense research. Finally, the role of spondylolisthesis reduction will likely be determined as further investigation into optimal sagittal balance and spinopelvic parameters is conducted. Future identification of ideal thresholds for sagittal vertical axis and slip angle that will prevent progression and reoperation will play an important role in surgical treatment planning. Current evidence supports surgical treatment of degenerative spondylolisthesis. While posterolateral spinal fusion remains the treatment of choice, the use of interbodies and decompressions without fusion may be efficacious in certain populations. However, additional high-quality evidence is needed, especially in newer areas of practice such as minimally invasive techniques and sagittal balance correction.

Effect of Single-Level Transforaminal Lumbar Interbody Fusion on Segmental and Overall Lumbar Lordosis in Patients with Lumbar Degenerative Disease

OBJECTIVE

To investigate the ability of transforaminal lumbar interbody fusion (TLIF) to improve lumbar lordosis (LL).

METHODS

In this retrospective study, 92 patients undergoing single-level TLIF to treat lumbar degenerative disease were divided into a low back pain, radiculopathy, and neurogenic claudication group according to their symptoms. Preoperative and postoperative measures, including segmental LL, whole LL, pelvic incidence (PI), pelvic tilt, thoracic kyphosis, sagittal vertical axis, visual analog scale for back and leg pain, and Oswestry Disability Index, were used to evaluate radiographic and clinical outcomes.

RESULTS

All clinical parameters were significantly improved after TLIF. There was no significant difference in any radiographic parameters in the low back pain group. In the radiculopathy and neurogenic claudication groups, all radiographic parameters were significantly changed after TLIF except for segmental LL and PI in both groups and pelvic tilt in the radiculopathy group. No statistically significant differences were found in improvement of segmental LL, PI, thoracic kyphosis, and visual analog scale (leg) between the radiculopathy and neurogenic claudication groups, whereas the differences in improvement of whole LL, pelvic tilt, PI-LL, sagittal vertical axis, visual analog scale (back), and Oswestry Disability Index were significant between the 2 groups.

CONCLUSIONS

For patients with neurogenic leg symptoms owing to single-level lumbar degenerative disease, whole LL was improved after TLIF as a result of spontaneous restoration of lordosis at the unfused lumbar levels.