Clinical outcomes and sagittal alignment of single-level unilateral instrumented transforaminal lumbar interbody fusion with a 4 to 5-year follow-up

Segmental Lordosis After Open Transforaminal Lumbar Interbody Fusion Using Expandable Oblique Versus Static Anterior Banana Cages

BACKGROUND AND OBJECTIVES

Expandable oblique interbody cages have gained popularity because of their suitability in minimally invasive surgical approaches and their ease of operative insertion. We aimed to determine whether static anteriorly placed banana cages or expandable obliquely placed cages provide greater lordosis when performing open transforaminal lumbar interbody fusion with concomitant posterior column osteotomy (PCO).

METHODS

We performed a single-surgeon retrospective consecutive cohort study which compared patients who underwent transforaminal lumbar interbody fusion using a static anteriorly placed banana cage vs an expandable obliquely placed cage. All TLIFs were performed open with PCO and included patients with focal degenerative pathology as well as global spinal deformity. Patient data were collected preoperatively, at 6-month follow-up, and at the last available follow-up. The primary outcome was defined as the change in segmental lordosis (ΔSL) measured using 6-month postoperative upright lumbar spine x-rays.

RESULTS

In total, 210 patients met inclusion criteria, including a total of 227 static cages and 100 expandable cages. The median ΔSL for the expandable cohort was significantly higher than the static cohort (6.1° [2.4, 8.4] vs 4.1° [1.3, 6.9], P = .016). This difference persisted after multivariate regression analyses and propensity score matching. Preoperative SL was found to have the greatest impact on ΔSL with a 3.23° increase for segments with preoperative SL < 15° compared with segments with preoperative SL ≥ 25° (P < .001). The overall median (T12-S1) delta lumbar lordosis (ΔLL) for all patients was 3.5° [-0.5, 10.2]. Although ΔLL was larger for static cages (median difference of 2.2°, P = .031), after propensity score matching, the expandable cage cohort experienced 3.24° greater ΔLL compared with the static cohort (P = .004).

CONCLUSION

Open TLIFs performed in conjunction with a PCO yielded 2.0° greater median ΔSL when using expandable obliquely placed cages compared with using static anteriorly placed banana cages. This represents a 50% increase between static and expandable cages. Cage type did not provide a clear advantage for overall ΔLL.

Predictors of Postoperative Segmental and Overall Lumbar Lordosis in Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Consecutive Case Series

STUDY DESIGN

Retrospective Case-Series.

OBJECTIVES

Due to heterogeneity in previous studies, the effect of MI-TLIF on postoperative segmental lordosis (SL) and lumbar lordosis (LL) remains unclear. Therefore, we aim to identify radiographic factors associated with lordosis after surgery in a homogenous series of MI-TLIF patients.

METHODS

A single-center retrospective review identified consecutive patients who underwent single-level MI-TLIF for grade 1 degenerative spondylolisthesis from 2015-2020. All surgeries underwent unilateral facetectomies and a contralateral facet release with expandable interbody cages. PROs included the ODI and NRS-BP for low-back pain. Radiographic measures included SL, disc height, percent spondylolisthesis, cage positioning, LL, PI-LL mismatch, sacral-slope, and pelvic-tilt. Surgeries were considered "lordosing" if the change in postoperative SL was ≥ +4° and "kyphosing" if ≤ -4°. Predictors of change in SL/LL were evaluated using Pearson's correlation and multivariable regression.

RESULTS

A total of 73 patients with an average follow-up of 22.5 (range 12-61) months were included. Patients experienced significant improvements in ODI (29% ± 22% improvement, P < .001) and NRS-BP (3.3 ± 3 point improvement, P < .001). There was a significant increase in mean SL (Δ3.43° ± 4.37°, P < .001) while LL (Δ0.17° ± 6.98°, P > .05) remained stable. Thirty-eight (52%) patients experienced lordosing MI-TLIFs, compared to 4 (5%) kyphosing and 31 (43%) neutral MI-TLIFs. A lower preoperative SL and more anterior cage placement were associated with the greatest improvement in SL (β = -.45° P = .001, β = 15.06° P < .001, respectively).

CONCLUSIONS

In our series, the majority of patients experienced lordosing or neutral MI-TLIFs (n = 69, 95%). Preoperative radiographic alignment and anterior cage placement were significantly associated with target SL following MI-TLIF.

Segmental Lordosis Restoration During Lumbar Degenerative Spinal Fusion: Surgical Techniques and Outcomes

The science of spinal alignment has progressed rapidly since Jean Doubousset described the cone of economy in the 1970s. It is now clearly established that global and regional spinal alignment are associated with improved patient-reported outcome and rates of success of lumbar spinal fusion. Evidence has now emerged that segmental level-by-level alignment is also associated with positive patient outcomes. As such, restoring sagittal alignment matched to spinopelvic morphology during degenerative lumbar surgery can optimize surgical outcomes by preventing adjacent segment pathology. This review focuses on the vital importance of spinal alignment in different spinal conditions, provides a guide for measurement of spinopelvic parameters, and outlines literature regarding lumbar restoration in degenerative spinal fusion.

Segmental Sagittal Alignment in Lumbar Spinal Fusion: A Review of Evidence-Based Evaluation of Preoperative Measurement, Surgical Planning, Intraoperative Execution, and Postoperative Evaluation

BACKGROUND AND OBJECTIVES

Maintaining and restoring global and regional sagittal alignment is a well-established priority that improves patient outcomes in patients with adult spinal deformity. However, the benefit of restoring segmental (level-by-level) alignment in lumbar fusion for degenerative conditions is not widely agreed on. The purpose of this review was to summarize intraoperative techniques to achieve segmental fixation and the impact of segmental lordosis on patient-reported and surgical outcomes.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, PubMed, Embase, Cochrane, and Web of Science databases were queried for the literature reporting lumbar alignment for degenerative lumbar spinal pathology. Reports were assessed for data regarding the impact of intraoperative surgical factors on postoperative segmental sagittal alignment and patient-reported outcome measures. Included studies were further categorized into groups related to patient positioning, fusion and fixation, and interbody device (technique, material, angle, and augmentation).

RESULTS

A total of 885 studies were screened, of which 43 met inclusion criteria examining segmental rather than regional or global alignment. Of these, 3 examined patient positioning, 8 examined fusion and fixation, 3 examined case parameters, 26 examined or compared different interbody fusion techniques, 5 examined postoperative patient-reported outcomes, and 3 examined the occurrence of adjacent segment disease. The data support a link between segmental alignment and patient positioning, surgical technique, and adjacent segment disease but have insufficient evidence to support a relationship with patient-reported outcomes, cage subsidence, or pseudoarthrosis.

CONCLUSION

This review explores segmental correction's impact on short-segment lumbar fusion outcomes, finding the extent of correction to depend on patient positioning and choice of interbody cage. Notably, inadequate restoration of lumbar lordosis is associated with adjacent segment degeneration. Nevertheless, conclusive evidence linking segmental alignment to patient-reported outcomes, cage subsidence, or pseudoarthrosis remains limited, underscoring the need for future research.

Comparison of Outcomes Between Endoscopic Transforaminal Lumbar Interbody Fusion and Minimally Invasive Transforaminal Lumbar Interbody Fusion in Patients With Single-Level Lumbar Degenerative Disease: A Retrospective Study

OBJECTIVE

The objective of this study was to compare the clinical and radiological outcomes of endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

METHODS

This retrospective study included 110 patients with single-level lumbar degenerative disease who underwent Endo-TLIF or MIS-TLIF between January 2019 and December 2021. Patients were divided into Endo-TLIF (n = 55) and MIS-TLIF groups (n = 55). Perioperative, clinical, and radiological outcomes were assessed.

RESULTS

The Endo-TLIF group had significantly lower blood loss and shorter hospital stay. However, the operation time was significantly longer and there was more x-ray exposure than in the MIS-TLIF group. There were no significant differences in complications between the groups. The Endo-TLIF group showed significantly lower creatine kinase levels than the MIS-TLIF group at 3 days postoperatively (P < 0.05), but not at 7 days postoperatively (P > 0.05). Oswestry Disability Index and visual analog scale scores were significantly reduced in both groups at different time points postoperation compared to preoperation. The visual analog scale score in the Endo-TLIF group was lower than that in the MIS-TLIF group at 3 days postoperatively. Moreover, no significant differences were found in fusion rates, lumbar lordosis, and lumbar segmental lordosis between the 2 groups (P > 0.05).

CONCLUSIONS

Endo-TLIF might be considered as an effective and reliable treatment option for single-level lumbar degeneration. It results in less trauma and faster postoperative recovery, but a longer operative time and more x-ray exposure than MIS-TLIF. Endo-TLIF has effects on clinical and radiological outcomes that are comparable to those of MIS-TLIF.

Comparison of Unilateral versus Bilateral Instrumented Transforaminal Lumbar Interbody Fusion in Lumbar Degenerative Diseases: A Minimum of 5-Year Follow-Up

Background and Objective: There is a paucity of literature comparing unilateral instrumented transforaminal lumbar interbody fusion (UITLIF) with bilateral instrumented TLIF (BITLIF) regarding radiological alignment, including the coronal balance, even though UITLIF might have asymmetric characteristics in the coronal plane. This retrospective study aimed to compare the clinical and long-term radiological outcomes of 1-level UITLIF and BITLIF in lumbar degenerative diseases (LDD) including lumbar spinal stenosis with or without spondylolisthesis (degenerative or spondylolytic). Materials and Methods: Patients who underwent 1-level UITLIF with two rectangular polyetheretherketone (PEEK) cages or BITLIF between November 2009 and June 2016 by four surgeons with ≥5 years of follow-up at a single hospital were included. We compared the clinical and radiological outcomes between the UITLIF and BITLIF. Results: In total, 63 and 111 patients who underwent UITLIF and BITLIF, respectively, were enrolled. The median follow-up was 85.55 months (range: 60-130). The UITLIF group had a significantly shorter operation time (185.0 [170.0-210.0] vs. 225.0 [200.0-265.0], p < 0.001) and lower estimated blood loss (300.0 [250.0-500.0] vs. 550.0 [400.0-800.0], p < 0.001) than the BITLIF group. Regarding the clinical outcomes, there were no significant differences in the intermittent claudication score (p = 0.495) and Kirkaldy-Willis criteria (p = 0.707) at 1 year postoperatively. The interval changes in the local coronal Cobb angle at the index level, L1-S1 lordotic angle, and coronal off-balance from the immediate postoperative radiograph to the last follow-up were not significantly different (p = 0.687, p = 0.701, and p = 0.367, respectively). Conclusions: UITLIF with two rectangular PEEK cages may provide comparable clinical outcomes and radiological longevity including coronal alignment to BITLIF in 1-level LDD. In addition, UITLIF has advantages over BITLIF in terms of operative time and blood loss.

Effect of Preoperative Severity and Location of Lumbar Intervertebral Disc Vacuum Phenomenon on Surgical Outcomes After Single-Level Transforaminal Lumbar Interbody Fusion

OBJECTIVE

This study aimed to examine whether preoperative severity and location of lumbar intervertebral disc vacuum phenomenon (VP) influence surgical outcomes after single-level transforaminal lumbar interbody fusion.

METHODS

We included 106 patients (age, 67.4 ± 10.4 years; 51 male/55 female) with lumbar degenerative diseases, who were treated with single-level transforaminal lumbar interbody fusion. Severity of VP (SVP) score was measured preoperatively. SVP score at fused disc was used as SVP (FS) score and at nonfused discs was used as SVP (non-FS) score. Surgical outcomes were assessed using the Oswestry Disability Index (ODI) and visual analog scale (VAS; low back pain (LBP), lower extremity pain, numbness, LBP in motion, in standing, and in sitting). The patients were divided into severe VP (FS or non-FS) and mild VP (FS or non-FS) groups, and surgical outcomes were compared between the 2 groups. Correlations between each SVP score and surgical outcomes were analyzed.

RESULTS

There were no differences in surgical outcomes between the severe VP (FS) and mild VP (FS) groups. Postoperative ODI, VAS score for LBP, lower extremity pain, numbness, and LBP in standing were significantly worse in the severe VP (non-FS) group than in the mild VP (non-FS) group. SVP (non-FS) scores significantly correlated with postoperative ODI, VAS score for LBP, lower extremity pain, numbness, and LBP in standing; however, SVP (FS) scores did not correlate with any surgical outcomes.

CONCLUSIONS

Preoperative SVP at fused disc is not associated with surgical outcomes; however, SVP at nonfused discs is correlated with clinical outcomes.

Relationship between lumbar lordosis, pelvic parameters, PI-LL mismatch and outcome after short fusion surgery for lumbar degenerative disease. Literature review, rational and presentation of public study protocol: RELApSE study (registry for evaluation of lumbar artrodesis sagittal alignEment)

Background

Vertebral arthrodesis for degenerative pathology of the lumbar spine still remains burdened by clinical problems with significant negative results. The introduction of the sagittal balance assessment with the evaluation of the meaning of pelvic parameters and spinopelvic (PI-LL) mismatch offered new evaluation criteria for this widespread pathology, but there is a lack of consistent evidence on long-term outcome.

Methods

The authors performed an extensive systematic review of literature, with the aim to identify all potentially relevant studies about the role and usefulness of the restoration or the assessment of Sagittal balance in lumbar degenerative disease. They present the study protocol RELApSE (NCT05448092 ID) and discuss the rationale through a comprehensive literature review.

Results

From the 237 papers on this topic, a total of 176 articles were selected in this review. The analysis of these literature data shows sparse and variable evidence. There are no observations or guidelines about the value of lordosis restoration or PI-LL mismatch. Most of the works in the literature are retrospective, monocentric, based on small populations, and often address the topic evaluation partially.

Conclusions

The RELApSE study is based on the possibility of comparing a heterogeneous population by pathology and different surgical technical options on some homogeneous clinical and anatomic-radiological measures aiming to understanding the value that global lumbar and segmental lordosis, distribution of lordosis, pelvic tilt, and PI-LL mismatch may have on clinical outcome in lumbar degenerative pathology and on the occurrence of adjacent segment disease.

Is unilateral pedicle screw fixation as effective as bilateral pedicle screw fixation in transforaminal lumbar interbody fusion: a meta-analysis of randomized controlled trials

PURPOSE

This meta-analysis aimed to investigate whether unilateral pedicle screw fixation (UPSF) is comparable to bilateral pedicle screw fixation (BPSF) in transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases.

METHODS

Up to September 2022, established electronic literature databases including PubMed, Web of Science, EMBASE, and the Cochrane Library were systematically searched. Randomized controlled trials (RCTs) published in English that compared the efficacy of UPSF versus BPSF in TLIF were included. The methodological quality was evaluated, relevant data was extracted, and suitable meta-analysis was carried out. Data of fusion rate, complications, cage migration, visual analog scale (VAS), and Oswestry Disability Index (ODI), total blood loss (TBL), operation time, and hospital stay were extracted and analyzed. Pooled mean differences and risk ratio (RR) along with 95% confidence intervals (95% CI) were calculated for the results.

RESULTS

Ten RCTs including 614 patients (UPSF = 294, BPSF = 320) were included in our meta-analysis. There were no significant differences in terms of fusion rate, VAS (VAS-BP and VAS-LP), ODI, complications, or hospital stay between UPSF and BPSF groups (P > 0.05, respectively). The UPSF group clearly had the advantage of less blood loss (SMD = -2.99, 95% CI [-4.54, -1.45], P = 0.0001) and operation time (SMD = -2.05, 95% CI [-3.10, -1.00], P = 0.0001). However, UPSF increased cage migration more than BPSF (10.7% vs 4.8%, RR = 2.23, 95% CI [1.07, 4.65],  P = 0.03).

CONCLUSION

According to the findings of this meta-analysis, UPSF is just as effective as BPSF in TLIF and may reduce blood loss and operation time. Nevertheless, UPSF may result in more cage migration than BPSF.

Can oblique lateral interbody fusion (OLIF) create more lumbosacral lordosis in lumbar spine surgery than minimally invasive transforaminal interbody fusion (MIS-TLIF)?

Objective

To compare the differences in the correction effect for lumbosacral lordosis and clinical outcomes between OLIF with/without posterior pedicle screw fixation (PSF) and MIS-TLIF through a retrospective cohort study.

Method

There were 98 consecutive patients originally enrolled for the study, but 15 patients were excluded due to intraoperative endplate injury or osteotomy performed for severe spinal deformity. Thus, 83 patients included in this study (36 males and 47 females, mean age 65.8 years) underwent single to three-segment OLIF (including OLIF + PSF and OLIF Standalone) or MIS-TLIF surgery from 2016 to 2018. The operation time, bleeding and blood transfusion, fusion rate, complication, pre-and postoperative visual analogue scale (VAS), Oswestry Disability Index (ODI) were evaluated. In addition, radiological parameters including lumbosacral lordosis (LL), fused segment lordosis (FSL), anterior disc height (ADH) and posterior disc height (PDH) were measured. The clinical outcomes, LL, FSL, ADH and PDH restored and were compared between the OLIF group, OLIF subgroups and MIS-TLIF group.

Results

The average operation time and intraoperative bleeding were significantly less in the OLIF group than in the MIS-TLIF group (163 ± 68 vs. 233 ± 79 min, 116 ± 148 vs. 434 ± 201 ml, P < 0.001). There was no statistically significant difference between the OLIF group and the MIS-TLIF group in VAS and ODI improvements, fusion rate, complication, LL and FSL correction (P > 0.05). The ADH and PDH increases in the OLIF group were more than that in MIS-TLIF group (P < 0.001). The correction of LL was significantly more in the OLIF + PSF group than in the MIS-TLIF group (9.9 ± 11.1 vs. 4.2 ± 6.1deg, P = 0.034).

Conclusion

OLIF and MIS-TLIF are both safe and effective procedures, capable of restoring lumbosacral lordosis and disc height partly. Combined with PSF, OLIF can achieve a better correction effect of lumbosacral lordosis than MIS-TLIF.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Does Interbody Cage Lordosis and Position Affect Radiographic Outcomes After Single-level Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The objective of this study was to determine if the degree of interbody cage lordosis and cage positioning are associated with changes in postoperative sagittal alignment after single-level transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA

Ideal sagittal alignment and lumbopelvic alignment have been shown to correlate with postoperative clinical outcomes. TLIF is one technique that may improve these parameters, but whether the amount of cage lordosis improves either segmental or lumbar lordosis (LL) is unknown.

METHODS

A retrospective review was performed on patients who underwent single-level TLIF with either a 5-degree or a 12-degree lordotic cage. LL, segmental lordosis (SL), disk height, center point ratio, cage position, and cage subsidence were evaluated. Correlation between center point ratio and change in lordosis was assessed using the Spearman correlation coefficient. Secondary analysis included multiple linear regression to determine independent predictors of change in SL.

RESULTS

A total of 126 patients were included in the final analysis, with 51 patients receiving a 5-degree cage and 75 patients receiving a 12-degree cage. There were no differences in the postoperative minus preoperative LL (∆LL) (12-degree cage: -1.66 degrees vs. 5-degree cage: -2.88 degrees, P =0.528) or ∆SL (12-degree cage: -0.79 degrees vs. 5-degree cage: -1.68 degrees, P =0.513) at 1-month follow-up. Furthermore, no differences were found in ∆LL (12-degree cage: 2.40 degrees vs. 5-degree cage: 1.00 degrees, P =0.497) or ∆SL (12-degree cage: 1.24 degrees vs. 5-degree cage: 0.35 degrees, P =0.541) at final follow-up. Regression analysis failed to show demographic factors, cage positioning, or cage lordosis to be independent predictors of change in SL. No difference in subsidence was found between groups (12-degree cage: 25.5% vs. 5-degree cage: 32%, P =0.431).

CONCLUSION

Lordotic cage angle and cage positioning were not associated with perioperative changes in LL, SL, or cage subsidence after single-level TLIF.

LEVEL OF EVIDENCE

Level III.

Comparison of short-term efficacy of MIS-TLIF and Endo-LIF in the treatment of single-segment degenerative lumbar diseases

Background

A prospective controlled study was conducted to compare the short-term clinical results and postoperative complications of minimally invasive transforaminal lumbar decompression and fusion (minimally invasive surgery transforaminal lumbar interbody fusion, MIS-TLIF) and percutaneous endoscope-assisted transforaminal lumbar interbody fusion (endoscopic lumbar interbody fusion, Endo-LIF) in the treatment of single-segment degenerative lumbar diseases, to provide some scientific guidance for clinicians to select surgical treatment for patients with lumbar degeneration.

Methods

From October 2020 to October 2021, a total of 62 patients were enrolled, with 31 patients in the MIS-TLIF group and 31 patients in the Endo-LIF group. All patients were followed up for 6 months. The following information from the two groups of patients was recorded: (1) operation time, radiation exposure time, intraoperative blood loss, bed rest time, and hospital stay; (2) ODI score (The Oswestry Disability Index), low back pain VAS score (Visual Analogue Scale), and lumbar vertebra JOA score (Japanese Orthopaedic Association Scores) 1 day before the operation; 1, 3, 6 days after operation; and 1, 3 and 6 months after operation. (3) X-ray evaluations of lumbar fusion at the last follow-up.

Results

There were significant differences in operation time, intraoperative fluoroscopy time, and hospitalization cost between the two groups. The MIS-TLIF group was significantly better than the Endo-LIF group, and the intraoperative bleeding volume of the Endo-LIF group was significantly better than that of the MIS-TLIF group, but there was no significant difference in postoperative bed rest time and postoperative hospital stay. There was no significant difference in the scores of ODI, VAS, and JOA between the two groups before and after the operation. At the last follow-up, the fusion rate was 100% in the MIS-TLIF group and 100% in the Endo-LIF group.

Conclusions

There was no significant difference in short-term clinical efficacy and safety between Endo-LIF and MIS-TLIF in the treatment of single-segment degenerative lumbar diseases, but MIS-TLIF was significantly better than Endo-LIF in terms of the operation time, hospitalization cost, and fluoroscopy time, and Endo-LIF was significantly better than MIS-TLIF in terms of intraoperative blood loss.

Comparison of electromagnetic and optical navigation assisted Endo-TLIF in the treatment of lumbar spondylolisthesis

Uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion (Endo-TLIF) with percutaneous pedicle screw fixation is a promising, minimally invasive method for the treatment of lumbar spondylolisthesis. However, repeated radiation exposure from X-rays and the steep learning curve remain to be improved.

Unilateral versus Bilateral Pedicle Screw Instrumented Transforaminal Interbody Fusion in a Single Level Lumbar Spondylolisthesis

Background The study aims to assess the efficiency, safety and outcome of unilateral pedicle screw fixation with TLIF (Transforaminal lumbar interbody fusion) vs bilateral pedicle screw fixation with TLIF in cases of single level spondylolisthesis by comparing clinical, functional outcome and the complication rates. Methods We prospectively collected demographics and clinical data of the patients with surgically treated single level lumbar spondylolisthesis grade 1 (n=60) with follow up and comparison between clinical/functional outcomes and complication rates between January 2020 and January 2021 at Cairo University hospitals. We allocated the patients with the unilateral pedicle screw fixation with TLIF as group A and the patients with the bilateral pedicle screw fixation with TLIF as group B. Results Clinical outcome showed statistical significance between Group A and Group B (P-value < 0.001); Functional outcome (using Oswestry’s disability index) between group A and B also showed statistical significance (P-value < 0.001) in favor of group B. Complications in group A was higher especially cage migration in 26.7% of cases with p-value of 0.026 while it was only present in 3.3% of the group B cases. Conclusion We concluded that the bilateral approach showed a statistically significant better clinically/functional outcomes with lower rates of complication in comparison with the unilateral approach.

What can we learn from long-term studies on chronic low back pain? A scoping review

PURPOSE

A scoping review was conducted with the objective to identify and map the available evidence from long-term studies on chronic non-specific low back pain (LBP), to examine how these studies are conducted, and to address potential knowledge gaps.

METHOD

We searched MEDLINE and EMBASE up to march 2021, not restricted by date or language. Experimental and observational study types were included. Inclusion criteria were: participants between 18 and 65 years old with non-specific sub-acute or chronic LBP, minimum average follow-up of > 2 years, and studies had to report at least one of the following outcome measures: disability, quality of life, work participation, or health care utilization. Methodological quality was assessed using the Effective Public Health Practice Project quality assessment. Data were extracted, tabulated, and reported thematically.

RESULTS

Ninety studies met the inclusion criteria. Studies examined invasive treatments (72%), conservative (21%), or a comparison of both (7%). No natural cohorts were included. Methodological quality was weak (16% of studies), moderate (63%), or strong (21%) and generally improved after 2010. Disability (92%) and pain (86%) outcomes were most commonly reported, followed by work (25%), quality of life (15%), and health care utilization (4%). Most studies reported significant improvement at long-term follow-up (median 51 months, range 26 months-18 years). Only 10 (11%) studies took more than one measurement > 2 year after baseline.

CONCLUSION

Patients with persistent non-specific LBP seem to experience improvement in pain, disability and quality of life years after seeking treatment. However, it remains unclear what factors might have influenced these improvements, and whether they are treatment-related. Studies varied greatly in design, patient population, and methods of data collection. There is still little insight into the long-term natural course of LBP. Additionally, few studies perform repeated measurements during long-term follow-up or report on patient-centered outcomes other than pain or disability.

Do Radiographic Results of Transforaminal Lumbar Interbody Fusion Vary with Cage Position in Patients with Degenerative Lumbar Diseases?

Objective

To investigate whether the radiographic results are affected by cage position in single‐level transforaminal lumbar interbody fusion (TLIF).

Method

Between January 2016 and June 2018, 130 patients (62 males and 68 females, average age: 55.28 ± 10.11 years) who underwent single‐level TLIF were analyzed retrospectively. Standing lateral radiographs of the lumbar spine were collected and evaluated preoperatively, postoperatively, and at the time of last follow‐up. Cage position in the fused segment was recorded using a central point ratio (CPR), which indicated the cage position. CPR is calculated by dividing the distance between the cage center point and the posterior extent of the superior endplate of the inferior vertebra by the length of the superior endplate of the inferior vertebra. Based on cage positions, the patients were divided into three groups: Anterior Group (n = 38); Middle Group (n = 68); and Posterior Group (n = 24). Segmental lumbar lordosis (SLL), foraminal height (FH), posterior disc height (PDH), and anterior disc height (ADH) were evaluated. A subanalysis was also performed on cage height within each group.

Results

The average follow‐up time of the patients was 35.20 ± 4.43 months. The mean values of CPR in Anterior Group, Middle Group, and Posterior Group were 0.64, 0.51, and 0.37, respectively. The FH, PDH, and ADH were significantly increased after TLIF in all groups (P < 0.05). There were significant differences in increase of SLL in Anterior Group (4.4°) and Middle Group (3.0°), but not in Posterior Group (0.3°). Furthermore, in the comparison of the three groups, the increase of SLL, FH, and PDH was statistically different (P < 0.05), while not for ADH (P > 0.05). The significant correlations in surgery were: CPR and ΔSLL (r = 0.584, P < 0.001), CPR and ΔFH (r = −0.411, P < 0.001), and CPR and ΔPDH (r = −0.457, P < 0.001). However, ADH had a positive correlation with cage height when the cage was located in anterior and middle of the endplate. Moreover, cage height had a positive correlation with SLL when the cage was located anteriorly and had a negative correlation with SLL when the cage was located posteriorly. FH and PDH both had a positive correlation with cage height in any cage position.

Conclusion

The cage located in different positions has different effects on radiographic results in single‐level TLIF. A thicker cage located anteriorly will gain maximum SLL and avoid the reduction of FH and PDH.

Bilateral lumbar ultrasound-guided erector spinae plane block versus local anaesthetic infiltration for perioperative analgesia in lumbar spine surgery: a randomized controlled trial

BACKGROUND

Lumbar spinal surgery is associated with severe postoperative pain. We examined the analgesic efficacy of bilateral lumbar ultrasound-guided erector spinae plane block (ESPB) with ropivacaine compared with local infiltration.

METHODS

Patients undergoing elective lumbar arthrodesis were randomly divided into two groups. Control group received 0.375 % ropivacaine 40 ml through the wound, and ESPB group received preoperative bilateral ESPB with 0.375 % ropivacaine 40 ml. Primary outcome was postoperative pain intensity at rest using a Numeric Rating Scale (NRS). Secondary outcomes included difference in pain intensity between pre-intervention and defined timepoints, total amount of opioid analgesic requested by the patients at the same timepoints, the incidence of any adverse event, and the length of hospital stay (LOS) after surgery.

RESULTS

Sixty patients were enrolled in the study. After surgery we detected a NRS value of 1.9 ± 1.5 in ESPB group and 5.9 ± 1.6 in Control group (p<0.001). About the opioid consumption we found a total sufentanil tablets consumption of 17 ± six and 10 ± three at 48h for Control group and ESPB group, respectively (p<0.001). Concerning LOS, 30 (100%) patients in the control group and 22(73.3%) in ESPB group were discharged after 72 hours (p=0.005).

CONCLUSIONS

Bilateral ultrasound-guided ESPB offers improved postoperative analgesia compared with local infiltration in patients undergoing lumbar spinal surgery.

Bone Metabolism in the Healing Process of Lumbar Interbody Fusion: Temporal Changes of Bone Turnover Markers

STUDY DESIGN

Prospective longitudinal study.

OBJECTIVE

The aim of this study was to evaluate temporal changes of bone turnover markers (BTMs) after lumbar spinal fusion in patients without osteoporosis.

SUMMARY OF BACKGROUND DATA

Radiological studies are the standard method to monitor bony fusion, but they do not allow a timely assessment of bone healing. BTMs react rapidly to changes in bone metabolism during fusion process and could be an additional tool to monitor this process.

METHODS

A total of 78 nonosteoporosis patients who had undergone one- or two-level transforaminal lumbar interbody fusion were included. Fusion status was assessed using computed tomography sagittal and coronal images. Serum levels of bone-specific alkaline phosphatase (BAP), procollagen type 1 amino-terminal propeptide (P1NP), and osteocalcin (OC) were measured to assess bone formation, and tartrate-resistant acid phosphatase 5b (TRACP-5b) was measured to assess bone resorption. Serum samples were obtained before surgery and at 1, 2, 4, 8, 13, 26, 39, and 52 weeks after surgery.

RESULTS

A solid fusion was achieved in 71 of 78 patients (91%), and seven patients resulted in pseudarthrosis. In the fusion group, the level of all BTMs once decreased at 1 postoperative week. Then, BAP and P1NP reached a peak at 4 weeks after surgery, and TRACP-5b and OC peaked at 8 weeks. Thereafter, the level of P1NP and TRACP-5b gradually got closer to the baseline over a year, and BAP kept high until 52 postoperative weeks. In the pseudarthrosis group, peak level of BTMs was significantly higher and the increased level of BAP and P1NP was kept until 52 weeks.

CONCLUSION

The present study demonstrated dynamics of BTMs after lumbar spinal fusion in patients without osteoporosis. These normal population data contribute as a baseline to evaluate the effect of osteogenic agents on bone metabolism after spinal fusion.Level of Evidence: 2.

Expandable vs. Static Transforaminal Lumbar Interbody Fusion Cages: 1-year Radiographic Parameters and Patient Reported Outcomes

BACKGROUND

Expandable transforaminal lumbar interbody fusion (TLIF) cages capable of multidirectional in situ expansion have gained popularity as they increase axial surface area for fusion and may enhance lordotic correction through a traditional MIS surgical corridor.

OBJECTIVE

To evaluate and compare the radiographic and clinical outcomes between a novel expandable vs. static MIS TLIF cage for the treatment of degenerative disc disease.

STUDY DESIGN

A single center retrospective review of 120 consecutive adult patients undergoing 1 or 2-level MIS TLIF with an expandable (n=60) or static cage was performed between 2015-2019. Preoperative and 1-year postoperative radiographic and clinical outcomes were assessed by upright flexion/extension radiographs and serial confidential surveys.

RESULTS

120 patients (mean age 63.5 years, 60.0 % female) undergoing 1 and 2-level MIS TLIF met inclusion criteria. A statistically significant reduction of spondylolisthesis, restoration of foraminal, anterior and posterior disc height was achieved in both cohorts, but greater in the ECC (all p<0.05). Comparable rates of fusion, 93% and 91% were observed in the ECC and SCC. A significant reduction in NRS back and ODI scores were observed in both cohorts but more pronounced in the ECC (5.9±2.4 to 2.2±1.9 and 37.3±16.2 to 17.1±15.2) vs. SCC (6.2±2.8 to 3.2±2.5 and 41.8±16.1 to 24.3±17.5) (p<0.05). One instance of cage migration requiring reoperation occurred in the ECC.

CONCLUSIONS

Taken together, these radiographic and clinical findings suggest an expandable cage placed through an MIS corridor represents a safe, equitable and efficacious alternative to a static TLIF in adults with degenerative lumbar pathology.

Preoperative Radiographic Prediction Tool for Early Postoperative Segmental and Lumbar Lordosis Alignment After Transforaminal Lumbar Interbody Fusion

Objective

Transforaminal lumbar interbody fusion (TLIF) is a common approach and results in varying degrees of lordosis correction. The purpose of this study is to determine preoperative radiographic spinopelvic parameters that predict change in postoperative segmental and lumbar lordosis after TLIF.

Materials & Methods

This study is a single surgeon retrospective review of one-level and two-level TLIFs from L3-S1. All patients underwent bilateral facetectomies, 10 mm TLIF cage (non-lordotic) insertions, and bilateral pedicle screw-rod construct placements. Pre- and post-operative X-rays were assessed for preoperative segmental lordosis (SL), lumbar lordosis (LL), and pelvic incidence (PI). Univariate and multi-predictor linear regression analyses were performed to determine the relationships between preoperative radiographic findings and change in early postoperative segmental and lumbar lordosis.

Results

Ninety-seven patients contributing 128 intervertebral segments were examined. The mean change in SL after TLIF was 7.3 (range: 0.10-28.9°, SD 6.39°). The mean change in LL after TLIF was 5.5˚ (range: -14.8-39.2°, standard deviation (SD) 7.16°). Greater preoperative LL predicted less postoperative LL correction, while greater preoperative PI predicted more postoperative SL and LL correction. Greater anterior disk height was noted to be associated with a decreased change in SL (∆SL). An annular tear on preoperative magnetic resonance imaging (MRI) predicted a 2.7° decrease in ∆SL. A Schmorl's node on preoperative MRI predicted a 4.0° decrease in change in LL (∆LL).

Conclusions

A greater preoperative lordosis and a lower spinopelvic mismatch lessen the potential for an increase in the postoperative SL and LL after a TLIF, which is likely due to a ‘ceiling’ effect of an otherwise optimized spinal alignment. A greater anterior disk height and the presence of an annular tear are associated with decreased ∆SL.

The technical feasibility and preliminary results of minimally invasive endoscopic-TLIF based on electromagnetic navigation: a case series

Background

Uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion (Endo-TLIF) with percutaneous pedicle screw fixation is a promising, minimally invasive method for the treatment of lumbar spondylolisthesis. However, repeated radiation exposure from X-rays and the steep learning curve remain to be improved.

Methods

This retrospective study explored the effects of electromagnetic navigation on improving Endo-TLIF with percutaneous pedicle screw fixation. Clinical information from 42 patients who had received Endo-TLIF with percutaneous pedicle screw fixation from May 2019 to November 2020 was analyzed retrospectively. The procedures were assisted under electromagnetic navigation. The rate of adjustment for guide wires, frequency of X-ray exposure, operative time, accuracy of pedicle screw location, and clinical outcomes were recorded.

Results

The mean follow-up for 42 patients was 11.9 ± 3.1 months. The mean age of the patients was 56.1 ± 9.26 years, with a female/male ratio of 25:17. According to postoperative CT scans and 3D reconstructions, the excellent and good rate of pedicle screws was 96.4%. The rate of adjustment for guide wires under the assistance of electromagnetic navigation was 1.78%, and the frequency of X-ray exposure was 8.27 ± 1.83. The operative time was 167.25 ± 28.16 min, including the duration of guide wire insertion (14.63 ± 5.45 min) and duration of decompression and cage placement (75.43 ± 13.97 min). The duration of hospitalization after operation was 2.59 ± 1.16 days. The preoperative VAS score was 7.51 ± 1.91, and the preoperative ODI was 82.42 ± 8.7%. At the last follow-up, the VAS score was 2.09 ± 0.59, and the ODI was 11.09 ± 3.2%. There were statistically significant improvements in the VAS score and ODI in all patients at the follow-up (p < 0.05).

Conclusions

Electromagnetic navigation can provide accurate positioning and guidance in real time, which improves the surgical efficiency of percutaneous pedicle screw placement and endoscopic decompression in Endo-TLIF with reduced radiation exposures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01148-9.

Comparison of clinical outcomes and spino-pelvic sagittal balance in degenerative lumbar spondylolisthesis: Minimally invasive oblique lumbar interbody fusion (OLIF) versus transforaminal lumbar interbody fusion (TLIF)

Spino-pelvic sagittal parameters are closely related to the lumbar degenerative diseases. The present study aims to compare clinical results and spino-pelvic sagittal balance treated with oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in patients with degenerative lumbar spondylolisthesis at single segment.We retrospectively reviewed and compared 28 patients who underwent OLIF (OLIF group) and 35 who underwent TLIF (TLIF group). Radiological results were evaluated with disc height (DH), foraminal height (FH), fused segment lordosis (FSL), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and sacral slope (SS). Clinical results were evaluated with the Oswestry Disability Index (ODI) and VAS for back and leg pain.The OLIF group showed higher improvement of DH and FH than the TLIF group at all time points after surgery (P < .05). No significant differences were found in PT, PI, and SS between the 2 groups (P > .05). Significant restoration of spino-pelvic sagittal balance was observed in the 2 groups after surgery. Significant differences in postoperative lumbar lordosis and fused segment lordosis were found between the 2 groups (P < .05). Significant difference in the improvement of symptoms was observed between the 2 groups. The OLIF group had lower VAS scores for back pain and ODI compared after surgery (P < .05).It can be concluded that there are exactly differences in improvement of radiographic parameters between 2 approaches, which confirmed that OLIF is better in restoring spinal alignment. Besides, due to the unique minimally invasive approach, OLIF did exhibit a greater advantage in early recovery after surgery.

Endoscopic Transforaminal Lumbar Interbody Fusion With a Single Oblique PEEK Cage and Posterior Supplemental Fixation

BACKGROUND

To demonstrate the feasibility of an endoscopically assisted minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF) and to study clinical outcomes with the use of a static oblique bullet-shaped cannulated poly-ether-ether-ketone (PEEK) lumbar interbody fusion cage in conjunction with platelet enriched plasma infused allograft cancellous chips and posterior supplemental fixation.

METHODS

In this retrospective study of 43 patients who underwent endoscopically assisted MIS-TLIF for spondylolisthesis (53.5%) and stenosis (46.3%), the Oswestry Disability Index, the visual analog scale (VAS) for back and leg pain, and the modified Macnab criteria were used as primary clinical outcome measures. Clinical outcomes were cross-tabulated against fusion grade using the Bridwell classification of interbody fusion.

RESULTS

The majority of patients (90.7%) had excellent (8/43; 18.6%) and good (31/43; 72.1%) Macnab outcomes. There were significant VAS back score reductions from an average preoperative values of 8.9070 to a postoperative VAS score of 3.8605, and a score of 2.7674 at final follow-up (P < .0001). The reductions in the VAS leg scores were also significant from preoperative score of 5.58 to a postoperative value of 2.16, and a final follow-up score of 1.67 (P < .0001); the Oswestry Disability Index score went from a preoperative value of 54.4 to 23.3 postoperatively and 18.5 at the final follow-up (P < .0001). The vast majority of patients (92.9%) with Bridwell grade I fusion had excellent and good Macnab outcomes (P = .027).

CONCLUSIONS

The authors recommend the use of an endoscope as an adjunct to MIS-TLIF, a minimally invasive spinal surgery technique in which many surgeons may be well versed and have a great deal of experience. Clinical outcomes with the endoscopic interbody fusion procedure with a static PEEK cage in conjunction with platelet-enriched bone allograft were favorable.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Feasibility study.

Interbody Fusions in the Lumbar Spine: A Review

BACKGROUND

Lumbar interbody fusion is among the most common types of spinal surgery performed. Over time, the term has evolved to encompass a number of different approaches to the intervertebral space, as well as differing implant materials. Questions remain over which approaches and materials are best for achieving fusion and restoring disc height.

QUESTIONS/PURPOSES

We reviewed the literature on the advantages and disadvantages of various methods and devices used to achieve and augment fusion between the disc spaces in the lumbar spine.

METHODS

Using search terms specific to lumbar interbody fusion, we searched PubMed and Google Scholar and identified 4993 articles. We excluded those that did not report clinical outcomes, involved cervical interbody devices, were animal studies, or were not in English. After exclusions, 68 articles were included for review.

RESULTS

Posterior approaches have advantages, such as providing 360° support through a single incision, but can result in retraction injury and do not always restore lordosis or correct deformity. Anterior approaches allow for the largest implants and good correction of deformities but can result in vascular, urinary, psoas muscle, or lumbar plexus injury and may require a second posterior procedure to supplement fixation. Titanium cages produce improved osteointegration and fusion rates but also increase subsidence caused by the stiffness of titanium relative to bone. Polyetheretherketone (PEEK) has an elasticity closer to that of bone and shows less subsidence than titanium cages, but as an inert compound PEEK results in lower fusion rates and greater osteolysis. Combination PEEK-titanium coating has not yet achieved better results. Expandable cages were developed to increase disc height and restore lumbar lordosis, but the data on their effectiveness have been inconclusive. Three-dimensionally (3D)-printed cages have shown promise in biomechanical and animal studies at increasing fusion rates and reducing subsidence, but additive manufacturing options are still in their infancy and require more investigation.

CONCLUSIONS

All of the approaches to spinal fusion have plusses and minuses that must be considered when determining which to use, and newer-technology implants, such as PEEK with titanium coating, expandable, and 3D-printed cages, have tried to improve upon the limitations of existing grafts but require further study.

Comparative Effectiveness of Laterally Placed Expandable versus Static Interbody Spacers: A 1-Year Follow-Up Radiographic and Clinical Outcomes Study

Study Design

Retrospective chart review.

Purpose

This study compared the clinical and radiographic outcomes of patients treated with expandable and static interbody spacers following minimally invasive lateral lumbar interbody fusion (MIS-LLIF) with 12-month follow-up.

Overview of Literature

A common surgical option for the treatment of degenerative disk disease (DDD) is MIS-LLIF using static or expandable spacers to restore disk height (DH), neuroforaminal height (NH), and segmental lordosis. Static spacers may require excessive trialing and aggressive impaction, potentially leading to endplate disruption and subsidence. Expandable spacers allow for in situ expansion to help address complications associated with static spacers.

Methods

This is an Institutional Review Board-exempt review of 69 patients (static, n=32; expandable, n=37) diagnosed with DDD who underwent MIS-LLIF at 1–2 contiguous level(s) using static or expandable spacers. Radiographic and clinical outcomes were collected and compared at pre- and postoperative time points up to 12 months.

Results

The expandable group had a significantly higher mean change in Visual Analog Scale (VAS) scores at 6 weeks, 6 months, and 12 months vs. static (∆VAS at 12 months: expandable, 6.7±1.3; static, 5.1±2.6). Mean improvement of Oswestry Disability Index (ODI) scores at 3, 6, and 12 months were significantly better for the expandable group vs. static (∆ODI at 12 months: expandable, 63.2±13.2; static, 29.8±23.4). Mean DH and NH significantly increased at final follow-up for both groups, with no significant difference in DH improvement between groups. The expandable mean NH improvement at 6 weeks and 6 months was significantly greater vs. static. Segmental lordosis significantly improved in the expandable group at all time intervals vs static. Subsidence rate at 12 months was significantly lower in the expandable group (1/46, 2.2%) vs. static (12/37, 32.4%).

Conclusions

Expandable spacers resulted in a significantly lower subsidence rate, improve segmental lordosis, and VAS and ODI outcomes at 12 months vs. static.

Comparative Effectiveness of Adjustable Lordotic Expandable versus Static Lateral Lumbar Interbody Fusion Devices: One Year Clinical and Radiographic Outcomes

Aims:

This study aims to understand the clinical and radiographic outcomes between patients treated with static and expandable interbody spacers with adjustable lordosis for minimally invasive (MIS) lateral lumbar interbody fusion (LLIF).

Background:

The use of large interbody spacers in MIS LLIF offers favorable clinical and radiographic results. Static interbody spacers may cause iatrogenic endplate damage and implant subsidence due to forceful impaction and excessive trialing. Expandable interbody spacers with adjustable lordosis offerin situexpansion that may optimize endplate contact and maximize and maintain sagittal alignment correction until fusion occurs.

Objective:

The objective of this study is to compare the clinical and radiographic outcomes between patients treated with static and expandable interbody spacers with adjustable lordosis for MIS LLIF.

Methods:

This is a multi-surgeon, retrospective, Institutional Review Board-exempt chart review of consecutive patients who underwent MIS LLIF at 1-2 contiguous level(s) using either a polyetheretherketone (PEEK) static (32 patients) or a titanium expandable spacer with adjustable lordosis (57 patients). The mean differences of radiographic and clinical functional outcomes were collected and compared from preoperative up to 12-month postoperative follow-up. Statistical results were significant if P<0.05.

Results:

The mean improvement of VAS back pain scores from preoperative to 6 and 12 months was significantly higher in the expandable group compared to the static group (P<0.05). Mean improvement of Oswestry Disability Index (ODI) scores from preoperative to 3, 6, and 12 months were significantly higher in the expandable group compared to the static group (P<0.001). The expandable group had a significantly greater mean improvement in segmental lordosis from preoperative to 6 weeks, 3, 6, and 12 months (P<0.001). For disc height, the mean improvement from preoperative to 6 weeks and 3 months was more significant in the expandable group compared to the static group (P<0.05). In the expandable group, the mean improvement from preoperative to 6 weeks, 3, and 6 months was significantly greater compared to the static group for neuroforaminal height (P<0.001). Subsidence was 0% in the expandable group and 32.4% (12/37) in the static group.

Conclusion:

This study showed significant positive clinical and radiographic outcomes for patients who underwent MIS LLIF using titanium expandable interbody spacers with adjustable lordosis based on significant changes in VAS back pain scores, ODI scores, and radiographic parameters at 12-month follow-up. There was a 0% subsidence rate in the expandable group, compared to a 32% subsidence rate in the static group.

Cage migration after unilateral instrumented transforaminal lumbar interbody fusion and associated risk factors: a modified measurement method

Objective

In this retrospective study, a modified measurement method was used to analyze cage migration during follow-up after unilateral instrumented transforaminal lumbar interbody fusion (TLIF) and identify associated factors.

Methods

We retrospectively evaluated 75 patients who had been treated with unilateral instrumented TLIF. Cage migration was quantitatively defined as anterior–posterior or lateral displacement of the cage.

Results

Five patients had significant cage migration (6.7%), but none developed severe neural symptoms during follow-up or underwent reoperation. The cages tended to migrate posteriorly or toward the side of surgery. The initial cage position and patient age were strongly associated with migration. Migration was less frequent when the cages were initially placed closer to the side of surgery. Patients of advanced age were more likely to develop anterior–posterior migration than were young patients.

Conclusion

Cage migration is related to the initial position of the cage. Particular attention is required when performing unilateral instrumented TLIF in patients of advanced age because they are most likely to develop cage migration. Quantification of cage migration is an effective method of exploring the associated factors.

Fracture of allograft interbody spacer resulting in post-operative radiculopathy: A case report

BACKGROUND

Allograft interbody spacers are utilized during transforaminal lumbar interbody fusion (TLIF) to reestablish anterior column support and disc height. While the TLIF technique offers many improvements over previous surgical methods, instrumentation and bone graft-related complications such as spacer misplacement or migration, screw fracture or misplacement, or rod breakage continue to be reported. The objective of this manuscript is to report on a fractured allograft interbody spacer that displaced into the neural foramen and resulted in impingement on the exiting nerve root that required revision.

CASE SUMMARY

A 50-year-old male had two-level TLIF with immediate post-operative right L5 radiculopathy. Computed tomography scan demonstrated a fractured allograft interbody spacer that displaced into the right neural foramen and impinged on the exiting L5 nerve root. Revision surgery was performed to remove the broken allograft fragments from the right L5 foramen and the intact portion of the spacer was left in place. The right leg L5 radicular pain resolved. At the last follow up 12 mo after the index procedure, computed tomography scan confirmed sound interbody and posterolateral fusion.

CONCLUSION

Displacement of broken allograft interbody spacer following TLIF procedures can result in neurological sequelae that require revision. To avoid such an occurrence, the authors recommend allowing sufficient time for the reconstitution of the graft in saline prior to use to decrease brittleness, to use an impactor size that is as close as possible to the spacer size and meticulous inspection of the cortical allograft spacer for any visible imperfection prior to insertion.

Assessing the Difference in Clinical and Radiologic Outcomes Between Expandable Cage and Nonexpandable Cage Among Patients Undergoing Minimally Invasive Transforaminal Interbody Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Minimally invasive transforaminal interbody fusion (MIS-TLIF) has been shown to have excellent outcomes for surgical management of degenerative disc disease. However, the challenge is in addressing coronal imbalance and restoring lumbar lordosis and sagittal alignment. Use of expandable cages in MIS-TLIF has been hypothesized to circumvent this disadvantage. An indirect meta-analysis of the evidence is presented comparing outcomes from expandable cages with those from nonexpandable cages, in patients undergoing MIS-TLIF.

METHODS

PRISMA guidelines were used to conduct a systematic review and meta-analysis to compare the clinical and radiologic outcomes of expandable cages and nonexpandable cages in patients undergoing MIS-TLIF.

RESULTS

Twelve studies (706 patients) were included in the meta-analysis. The mean increase in disc height was found to be significantly greater for the nonexpandable cages group than for the expandable cages group (1.33 mm; 95% confidence interval [CI], 1.28-1.38 vs. 1.14 mm,; 95% CI, 1.06-1.23; P < 0.001). No significant difference was found regarding change in lumbar lordosis at last follow-up between the 2 groups (P = 0.34). The mean change in segmental lordosis was found to be significantly higher for the expandable cage group (5.04°, 95% CI, 3.89-6.20 vs. 2.08°, 95% CI, 1.93-2.22; P < 0.001). We did not detect any significant difference in fusion rate (P = 0.33), subsidence rate (P = 0.41) or in reoperations (P = 0.56) at last follow-up between the 2 groups.

CONCLUSIONS

Our results indicate that there may not be a significant difference in clinical and radiologic parameters between expandable cages and nonexpandable cages among patients undergoing MIS-TLIF, and it is unclear if the higher cost of the expandable cages is justified.

Comparison of Segmental Lordosis and Global Spinopelvic Alignment After Single-Level Lateral Lumbar Interbody Fusion or Transforaminal Lumbar Interbody Fusion

BACKGROUND

Lateral lumbar interbody fusion (LLIF) has steadily increased in popularity. Compared with the traditional transforaminal lumbar interbody fusion (TLIF), LLIF is thought to allow for greater improvement in lordosis. However, there are limited direct comparison data on the degree of regional and global alignment change after single-level LLIF and TLIF procedures. This study compared the changes in spinal sagittal alignment in patients who underwent either procedure.

METHODS

A retrospective analysis of patients who underwent LLIF or TLIF for lumbar degenerative disease at a single institution was performed. Twenty patients who underwent single-level LLIF were matched to 20 patients who underwent single-level TLIF by gender and level of interbody fusion. All included patients had preoperative and postoperative standing scoliosis radiographs. Changes in segmental lordosis (SL) at the fused level, lumbar lordosis (LL), sagittal vertical axis, and pelvic incidence-LL mismatch (PI-LL) were measured. Statistical analysis was performed using paired and unpaired Student's t-tests. Means were reported with standard error.

RESULTS

Within each group, 2, 4, and 14 patients had cages placed at L2-3, L3-4, and L4-5, respectively. The LLIF group demonstrated significantly increased SL compared with the TLIF group (+4.9° ± 3.0 vs. +2.6° ± 1.7, P = 0.01). LL, sagittal vertical axis, and PI-LL changes did not differ significantly between groups.

CONCLUSIONS

LLIF achieved greater improvements in SL than TLIF. However, regionally and globally, there were no significant differences with either procedure after a single-level intervention. The increased lordosis from LLIF compared with TLIF may be more impactful globally in multilevel fusions.

Clinical, Functional, and Radiologic Outcome of Single- and Double-Level Transforaminal Lumbar Interbody Fusion in Patients with Low-Grade Spondylolisthesis

Objective:

The main objective is to determine the functional, clinical, and radiological outcome of patients with low-grade spondylolisthesis undergoing single- or double-level transforaminal lumbar interbody fusion (TLIF).

Materials and Methods:

This quasi-interventional study was conducted during a 2-year period from 2016 to 2018 in Shiraz, Southern Iran. We included all the adult (≥18 years) patients with low-grade spondylolisthesis (Meyerding Grade I and II) who underwent single- or double-level TLIF in our center. The spinopelvic parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), and segmental LL (SLL) were measured. The pain intensity and disability were measured utilizing the visual analog scale (VAS) for back and leg pain and Oswestry Disability Index (ODI), respectively, after 1 year.

Results:

Overall, we included a total number of 50 patients with mean age of 54.1 ± 10.48 years. After the surgery, the PI (P = 0.432), PT (P = 0.782), and SS (P = 0.466) were not found to be statistically changed from the baseline. However, we found that single- or double-level TLIF was associated with increased LL (P < 0.001) and SLL (P < 0.001). Regarding the clinical outcome measures, both back (P = 0.001) and leg (P < 0.001) VAS improved after the surgery significantly. In addition, we found that improved leg VAS was positively correlated with improved ODI (r = 0. 634; P < 0.001).

Conclusion:

Single- or double-level TLIF is associated with increased global and SLL along with improved leg and back pain and disability in patients with low-grade spondylolisthesis. Interestingly, improved leg pain is correlated to improved disability in these patients.

Comparison of Minimally Invasive and Open Transforaminal Lumbar Interbody Fusion for Lumbar Disc Herniation: A Retrospective Cohort Study

Background

This cohort study compared the efficacy and safety of minimally invasive versus open transforaminal lumbar interbody fusion (Mis-TLIF versus Open-TLIF) for lumbar disc herniation with radiculopathy.

Material/Methods

From July 2016 to September 2017, we recruited 37 patients suffering from lumbar disc herniation with radiculopathy. Seventeen patients underwent Mis-TLIF (Mis group) and 20 patients underwent Open-TLIF (Open group). Baseline characteristics were similar between the 2 groups before surgery. We compared postoperative clinical and radiological outcomes between the 2 groups.

Results

Compared to patients in the Open group, patients in the Mis group has significantly less intraoperative hemorrhage, drainage fluid, time to go, and hospital stay after surgery, but had longer operation times (P<0.05). These 2 groups had similar postoperative hemoglobin reduction and drain removal time. In addition, the postoperative back and leg pain and intervertebral height reduction at 3 months after surgery in the Mis group were remarkably lower than those in the Open group. There was no significant difference in postoperative Oswestry disability index (ODI) or intervertebral height change immediately after surgery and at 1 month postoperatively between the 2 groups.

Conclusions

Mis-TLIF shows some benefits in lumbar disc herniation compared to Open-TLIF in terms of intraoperative hemorrhage, drainage fluid, time to go, hospital stay after surgery, and postoperative back and leg pain.

Pedicle Screw with Cement Augmentation in Unilateral Transforaminal Lumbar Interbody Fusion: A 2-Year Follow-Up Study

OBJECTIVE

To evaluate safety and efficacy of pedicle screw with polymethyl methacrylate (PMMA) augmentation in unilateral transforaminal lumbar interbody fusion (uTLIF) in osteoporotic patients.

METHODS

We randomly divided 50 osteoporotic patients with degenerative lumbar diseases diagnosed between February 2014 and November 2015 into 2 groups. One group underwent standard uTLIF, and the other group underwent uTLIF with PMMA augmentation. All patients were scheduled to attend a series of regular follow-up evaluations. Oswestry Disability Index, Japanese Orthopaedic Association score, visual analog scale score, lumbar lordotic angle, segmental lordotic angle, and disc space height (DSH) at each follow-up were collected and analyzed.

RESULTS

The 2-year follow-up was completed by 24 patients in the uTLIF group and 23 patients in the PMMA group. Oswestry Disability Index, Japanese Orthopaedic Association score, and visual analog scale score showed significant improvements after surgery in both groups, with no significant difference between groups. DSH in the uTLIF group was 8.7 ± 2.3 mm and in the PMMA group was 10.7 ± 1.6 mm. Fusion rate in the uTLIF group was 19/24 and in the PMMA group was 21/23. DSH and fusion rate in the PMMA group were higher than those in the uTLIF group. No severe complications were observed after PMMA injection.

CONCLUSIONS

Pedicle screw with PMMA augmentation can increase fixation stability and reduce DSH loss in uTLIF. Moreover, PMMA in the vertebral body did not impede the interbody fusion ability in uTLIF.

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.

Iatrogenic Flatback and Flatback Syndrome: Evaluation, Management, and Prevention

Flatback syndrome can be a significant source of disability, affecting stance and gait, and resulting in significant pain. Although the historical instrumentation options for thoracolumbar fusion procedures have been commonly regarded as the etiology of iatrogenic flatback, inappropriate selection, or application of modern instrumentation can similarly produce flatback deformities. Patients initially compensate with increased lordosis at adjacent lumbar segments and reduction of thoracic kyphosis. As paraspinal musculature fatigues and discs degenerate, maintaining sagittal balance requires increasing pelvic retroversion and hip extension. Ultimately, disc degeneration at adjacent levels overcomes compensatory mechanisms, resulting in sagittal imbalance and worsening symptoms. Nonoperative management for sagittally imbalanced (sagittal vertical axis>5 cm) flatback syndrome is frequently unsuccessful. Despite significant complication rates, surgical management to recreate lumbar lordosis using interbody fusions and/or osteotomies can significantly improve quality of life.

Effectiveness and safety of unilateral pedicle screw fixation in transforaminal lumbar interbody fusion (TLIF): a systematic review and meta-analysis

PURPOSE

To evaluate the effectiveness and safety of unilateral pedicle screw fixation in transforaminal lumbar interbody fusion (TLIF) by comparing with bilateral pedicle screw fixation.

MATERIALS AND METHODS

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trial database were used to search and identify clinical prospective trials that evaluated the efficacy and safety of unilateral fixation as compared with bilateral fixation in TLIF surgery. The methodological qualities of studies were assessed using the PEDro (Physiotherapy Evidence Database) score and Newcastle-Ottawa Scale.

RESULTS

Fourteen prospective studies comprising 954 participants were analyzed. Data synthesis show lower fusion rate (P = 0.03) and more cage migration (P = 0.04) in unilateral group compared to bilateral group. There was no significant difference in visual analog scale (VAS), Oswestry Disability Index (ODI), the Short Form 36 Health Survey (SF-36) physical component score (PCS), and length of hospital stay between unilateral and bilateral groups. The unilateral group had shorter operative time (P < 0.00001) and less blood loss (P = 0.0007).

CONCLUSIONS

Based on this systematic review and meta-analysis, the unilateral fixation in TLIF may achieve a similar clinical outcome and reduce blood loss and operative time when compared with that in bilateral fixation. However, the unilateral fixation may produce lower fusion rate and more cage migration than bilateral fixation in TLIF.

Expandable vs Static Cages in Transforaminal Lumbar Interbody Fusion: Radiographic Comparison of Segmental and Lumbar Sagittal Angles

BACKGROUND: One criticism of transforaminal lumbar interbody fusion (TLIF) is the inability to increase segmental lordosis (SL). Expandable interbody cages are a relatively new innovation theorized to allow improvement in SL.

OBJECTIVE: To compare changes in SL and lumbar lordosis (LL) after TLIF with nonexpandable vs expandable cages.

METHODS: We performed a retrospective cohort study of patients who were ≥18 years old and underwent single-level TLIF between 2011 and 2014. Patients were categorized by cage type (static vs expandable). Primary outcome of interest was change in SL and LL from preoperative values to those at 1 month and 1 year postoperatively.

RESULTS: A total of 89 patients were studied (48 nonexpandable group, 41 expandable group). Groups had similar baseline characteristics. For SL, median (interquartile range) improvement was 3° for nonexpandable and 2° for expandable (unadjusted, P = .09; adjusted, P = .68) at 1 month postoperatively, and 3° for nonexpandable and 1° for expandable (unadjusted, P = .41; adjusted, P = .28) at 1 year postoperatively. For LL, median improvement was 1° for nonexpandable and 2° for expandable (unadjusted, P = .20; adjusted, P = .21), and 2° for nonexpandable and 5° for expandable (unadjusted, P = .15; adjusted, P = .51) at 1 year postoperatively. After excluding parallel expandable cages, there was still no difference in SL or LL improvement at 1 month or 1 year postoperatively between static and expandable cages (both unadjusted and adjusted, P &gt; .05).

CONCLUSION: Patients undergoing single-level TLIF experienced similar improvements in SL and LL regardless of whether nonexpandable or expandable cages were placed.

CHANGES IN RADIOGRAPHIC PARAMETERS AFTER MINIMALLY INVASIVE LUMBAR INTERBODY FUSION

Objective : This study aims to evaluate changes in lumbosacral parameters after minimally invasive lumbar interbody fusion. The secondary aim was to evaluate whether interbody cage shape (crescent shaped or rectangular) would influence the results. Method : Retrospective analysis of 70 patients who underwent one or two level lumbar interbody fusion through a minimally invasive posterolateral approach. This included midline preservation and unilateral facetectomy. Pre- and postoperative (three to six months postoperative) radiographs were used for measuring lumbar lordosis (LL), segmental lordosis (SL) at the level of interbody fusion, and sacral slope (SS). Further analyses divided the patients into Roussouly lumbar subgroups. Results : LL was significantly reduced after surgery (59o:39o, p=0.001) as well as the SS (33.8o:31.2o, p=0.05). SL did not change significantly (11.4:11.06, p=0.85). There were no significant differences when comparing patients who received crescent shaped cage (n=27) and rectangular cage (n=43). Hypolordotic patients (Roussouly types 1 and 2) had radiographic improvement in comparison to normolordotic and hyperlordotic groups (types 3 and 4). Conclusion : Minimally invasive lumbar interbody fusion caused reduction in lumbosacral parameters. Cage shape had no influence on the results.