Multilevel extreme lateral interbody fusion (XLIF) and osteotomies for 3-dimensional severe deformity: 25 consecutive cases

Assessing the differences in operative and patient-reported outcomes between lateral approaches for lumbar fusion: a systematic review and indirect meta-analysis

OBJECTIVE

Anterior-to-psoas lumbar interbody fusion (ATP-LIF), more commonly referred to as oblique lateral interbody fusion, and lateral transpsoas lumbar interbody fusion (LTP-LIF), also known as extreme lateral interbody fusion, are the two commonly used lateral approaches for performing a lumbar fusion procedure. These approaches help overcome some of the technical challenges associated with traditional approaches for lumbar fusion. In this systematic review and indirect meta-analysis, the authors compared operative and patient-reported outcomes between these two select approaches using available studies.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, the authors conducted an electronic search using the PubMed, EMBASE, and Scopus databases for studies published before May 1, 2019. Indirect meta-analysis was conducted on fusion rate, cage movement (subsidence plus migration), permanent deficits, and transient deficits; results were depicted as forest plots of proportions (effect size [ES]).

RESULTS

A total of 63 studies were included in this review after applying the exclusion criteria, of which 26 studies investigated the outcomes of ATP-LIF, while 37 studied the outcomes of LTP-LIF. The average fusion rate was found to be similar between the two groups (ES 0.97, 95% CI 0.84-1.00 vs ES 0.94, 95% CI 0.91-0.97; p = 0.561). The mean incidence of cage movement was significantly higher in the ATP-LIF group compared with the LTP-LIF group (stand-alone: ES 0.15, 95% CI 0.06-0.27 vs ES 0.09, 95% CI 0.04-0.16 [p = 0.317]; combined: ES 0.18, 95% CI 0.07-0.32 vs ES 0.02, 95% CI 0.00-0.05 [p = 0.002]). The mean incidence of reoperations was significantly higher in patients undergoing ATP-LIF than in those undergoing LTP-LIF (ES 0.02, 95% CI 0.01-0.03 vs ES 0.04, 95% CI 0.02-0.07; p = 0.012). The mean incidence of permanent deficits was similar between the two groups (stand-alone: ES 0.03, 95% CI 0.01-0.06 vs ES 0.05, 95% CI 0.01-0.12 [p = 0.204]; combined: ES 0.03, 95% CI 0.01-0.06 vs ES 0.03, 95% CI 0.00-0.08 [p = 0.595]). The postoperative changes in visual analog scale (VAS) and Oswestry Disability Index (ODI) scores were both found to be higher for ATP-LIF relative to LTP-LIF (VAS: weighted average 4.11 [SD 2.03] vs weighted average 3.75 [SD 1.94] [p = 0.004]; ODI: weighted average 28.3 [SD 5.33] vs weighted average 24.3 [SD 4.94] [p < 0.001]).

CONCLUSIONS

These analyses indicate that while both approaches are associated with similar fusion rates, ATP-LIF may be related to higher odds of cage movement and reoperations as compared with LTP-LIF. Furthermore, there is no difference in rates of permanent deficits between the two procedures.

Early Postoperative Loss of Disc Height Following Transforaminal and Lateral Lumbar Interbody Fusion: A Radiographic Analysis

Study Design

Retrospective comparative radiological study.

Purpose

To analyze the difference in early disc height loss following transforaminal and lateral lumbar interbody fusion (TLIF and LLIF).

Overview of Literature

Minimal disc height loss facilitated by the polyaxial screw heads can occur naturally due to mechanical loading following lumbar fusion procedures. This loss does not usually cause any significant foraminal narrowing. However, when there is concomitant cage subsidence, symptomatic foraminal compromise could occur, especially when posterior decompression is not performed. It is not known whether the type of procedure, TLIF or LLIF, could influence this phenomenon.

Methods

Retrospectively, patients who underwent TLIF and LLIF for various degenerative conditions were shortlisted. Each of their fused levels with the cage in situ was analyzed independently, and the preoperative, postoperative, and follow-up disc height measurements were compared between the groups. In addition, the total disc height loss since surgery was calculated at final follow-up and was compared between the groups.

Results

Forty-six patients (age, 64.1±8.9 years) with 70 cage levels, 35 in each group, were selected. Age, sex, construct length, preoperative disc height, cage height, and immediate postoperative disc height were similar between the groups. By 3 months, disc height of the TLIF group was significantly less and continued to decrease over time, unlike in the LLIF group. By 1 year, the TLIF group demonstrated greater disc height loss (2.30±1.3 mm) than the LLIF group (0.89±1.1 mm). However, none of the patients in either group had any symptomatic complications throughout follow-up.

Conclusions

Although our study highlights the biomechanical advantage of LLIF over TLIF in maintaining disc height, none of the patients in our cohort had symptomatic complications or implant-related failures. Hence, TLIF, as it incorporates posterior decompression, remains a safe and reliable technique despite the potential for greater disc height loss.

Lateral lumbar interbody fusion in adult spine deformity - A review of literature

INTRODUCTION

Surgery for adult spine deformity presents a challenging issue for spinal surgeons with high morbidity rates reported in the literature. The minimally invasive lateral approach aims at reducing these complications while maintaining similar outcomes as associated with open spinal surgeries. The aim of this paper is to review the literature on the use of lateral lumbar interbody fusion in the cases of adult spinal deformity.

METHODS

A literature review was done using the healthcare database Advanced Research on NICE and NHS website using Medline. Search terms were "XLIF" or "LLIF" or "DLIF" or "lateral lumbar interbody fusion" or "minimal invasive lateral fusion" and "adult spinal deformity" or "spinal deformity".

RESULTS

A total of 417 studies were considered for the review and 44 studies were shortlisted after going through the selection criteria. The data of 1722 patients and 4057 fusion levels were analysed for this review. The mean age of the patients was 65.18 years with L4/5 being the most common level fused in this review. We found significant improvement in the radiological parameters (lordosis, scoliosis, and disk height) in the pooled data. Transient neurological symptoms and cage subsidence were the two most common complications reported.

CONCLUSION

LLIF is a safe and effective approach in managing adult spinal deformity with low morbidity and acceptable complication rates. It can be used alone for lower grades of deformity and as an adjuvant procedure to decrease the magnitude of open surgeries in high-grade deformities.

Stem Cells and Spinal Fusion

BACKGROUND

This manuscript is a review of the literature investigating the use of mesenchymal stem cells (MSCs) being applied in the setting of spinal fusion surgery. We mention the rates of pseudarthrosis, discuss current bone grafting options, and examine the preclinical and clinical outcomes of utilizing MSCs to assist in successfully fusing the spine.

METHODS

A thorough literature review was conducted to look at current and previous preclinical and clinical studies using stem cells for spinal fusion augmentation. Searches for PubMed/MEDLINE and ClinicalTrials.gov through January 2021 were conducted for literature mentioning stem cells and spinal fusion.

RESULTS

All preclinical and clinical studies investigating MSC use in spinal fusion were examined. We found 19 preclinical and 17 clinical studies. The majority of studies, both preclinical and clinical, were heterogeneous in design due to different osteoconductive scaffolds, cells, and techniques used. Preclinical studies showed promising outcomes in animal models when using appropriate osteoconductive scaffolds and factors for osteogenic differentiation. Similarly, clinical studies have promising outcomes but differ in their methodologies, surgical techniques, and materials used, making it difficult to adequately compare between the studies.

CONCLUSION

MSCs may be a promising option to use to augment grafting for spinal fusion surgery. MSCs must be used with appropriate osteoconductive scaffolds. Cell-based allografts and the optimization of their use have yet to be fully elucidated. Further studies are necessary to determine the efficacy of MSCs with different osteoconductive scaffolds and growth/osteogenic differentiation factors.

LEVEL OF EVIDENCE

3.

Overview of Minimally Invasive Spine Surgery

Minimally invasive spine surgery (MISS) has continued to evolve over the past few decades, with significant advancements in technology and technical skills. From endonasal cervical approaches to extreme lateral lumbar interbody fusions, MISS has showcased its usefulness across all practice areas of the spine, with unique points of access to avoid pertinent neurovascular structures. Adult spine deformity has also recognized the importance of minimally invasive techniques in its ability to limit complications and to provide adequate sagittal alignment correction and improvements in patients' functional status. Although MISS has continued to make significant progress clinically, consideration must also be given to its economic impact and the learning curve surgeons experience in adding these procedures to their armamentarium. This review examines current innovations in MISS, as well as the economic impact and future directions of the field.

Stem Cells and Spinal Fusion

There are a number of bone regeneration therapeutics available to aid spinal fusion; however, many are associated with pseudarthrosis, inflammation, and other complications. Mesenchymal stem cells for fusion has been promoted to mitigate these risks and achieve successful bony fusion. This article reviews the clinical studies available with use in spinal fusion. Preliminary results demonstrate that stem cells can provide high rates of fusion, comparable to autograft, without associated morbidity. Autologous and allogeneic stem cell sources showed similar rates of fusion in this review. Further research is required to evaluate which clinical situations are the optimum for stem cell use.

Clinical and Radiographic Evaluation of Multilevel Lateral Lumbar Interbody Fusion in Adult Degenerative Scoliosis

STUDY DESIGN

Retrospective review of prospective data.

OBJECTIVE

The objective of this study was to describe the clinical, radiographic, and complication-related outcomes through ≥1-year of 27 patients who underwent lateral lumbar interbody fusion (LLIF) with posterior instrumentation to treat ≥3 contiguous levels of degenerative lumbar scoliosis.

SUMMARY OF BACKGROUND DATA

Multilevel disease has traditionally been treated with open posterior fusion. Literature on multilevel LLIF is limited. We present our experience with utilizing LLIF to treat multilevel degenerative scoliosis.

METHODS

Clinical outcomes were evaluated using VAS, SF-12, and ODI. Radiographic outcomes included pelvic tilt, pelvic incidence, lumbar lordosis, pelvic incidence-lumbar lordosis mismatch, Cobb angle, and cage subsidence. Perioperative and long-term complications through the ≥1-year final-postoperative visit were reviewed; transient neurological disturbances were assessed independently. Demographic, comorbidity, operative, and recovery variables, including opioid use, were explored for association with primary outcomes.

RESULTS

Mean time to final-postoperative visit was 22.5 months; levels treated with LLIF per patient, 3.7; age, 66 years; and lateral operative time, 203 minutes. EBL was ≤100 mL in 74% of cases. Clinical outcomes remained significantly improved at ≥1-year. Cobb angle was corrected from 21.1 to 7.9 degrees (P<0.001), lordosis from 47.3 to 52.6 degrees (P<0.001), and mismatch from 11.4 to 6.4 degrees (P=0.003). High-grade subsidence occurred in 3 patients. Subsidence did not significantly impact primary outcomes. In total, 11.1% returned to the operating room for complication-related intervention over nearly 2-years; 37% experienced complications. Experiencing a complication was associated with having an open-posterior portion (P=0.048), but not with number of LLIF levels treated, or with clinical or radiographic outcomes. No patients experienced protracted neurological deficits; psoas weakness was associated with increased lateral operative time (P=0.049) and decreased surgeon experience (P=0.028).

CONCLUSIONS

Patients who underwent multilevel LLIF with adjunctive posterior surgery had significant clinical and radiographic improvements. Complication rates were similar compared to literature on single-level LLIF. LLIF is a viable treatment for multilevel degenerative scoliosis.

The impact of adding posterior instrumentation to transpsoas lateral fusion: a systematic review and meta-analysis

OBJECTIVETranspsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumentation posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors' knowledge, the literature on comparison of the two approaches is sparse.METHODSThe authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guidelines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP).RESULTSA total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confidence interval [CI] 0.04-0.11) compared to TPP (0.03, 95% CI 0.01-0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10-0.26) compared to TPP (0.03, 95% CI 0.00-0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient deficits were found to be comparable between the two groups.CONCLUSIONSThese results appear to suggest that addition of posterior instrumentation to transpsoas fusion is associated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique.

Subsidence Rates After Lateral Lumbar Interbody Fusion: A Systematic Review

OBJECTIVE

The evidence regarding the consequences of subsidence with lateral lumbar interbody fusion (LLIF) has been sparse. The objective of this study is to calculate the incidence of subsidence and reoperation for subsidence after LLIF. A secondary outcome examined the quantitative degree of subsidence by calculating the percent change in the height of the intervertebral space secondary to interbody subsidence at various postoperative follow-up times.

METHODS

Following the MOOSE (Meta-analysis [and Systematic Review] Of Observational Studies in Epidemiology) guidelines, a systematic review searched for all cohort studies that focused on subsidence rates after LLIF, including extreme lateral interbody fusions (XLIFs) and direct lateral interbody fusion. Neoplastic, infectious, and/or metabolic indications for LLIF were similarly excluded because these diseases may compromise bone quality and, thus, confound the rate of cage subsidence. Corpectomies were removed from the systematic review because 1) indications for removal of vertebral body typically reflect those excluded diseases and 2) subsidence refers to a different biomechanical process.

RESULTS

This systematic review identified a subsidence incidence with LLIF of 10.3% (N = 141/1362 patients in 14 articles) and reoperation rate for subsidence of 2.7% (N = 41/1470 patients in 16 articles). In the secondary outcome measure, the disc height decreased from 5.6% after 3 months, 6.0% after 6 months, and 10.2% after 12 months, to 8.9% after 24 months (P < 0.001).

CONCLUSIONS

Subsidence after LLIF carries a nonnegligible risk that may be incorporated in surgical consent discussions in selected patients.

Complications following single-level interbody fusion procedures: an ACS-NSQIP study

BACKGROUND

Controversy exists over the ability of various lumbar interbody fusion techniques to realign global and regional balance and their effect on patient outcomes. This is a retrospective cohort study to compare thirty-day postoperative outcomes between anterior and posterior interbody fusion techniques within a large national database.

METHODS

A retrospective cohort study utilizing the National Surgical Quality Improvement Program (NSQIP) database included 2,372 (29.9%) single-level anterior/direct lateral interbody fusions (ALIF/DLIF) and 5,563 (70.1%) single-level posterior/transforaminal lateral interbody fusions (PLIF/TLIF) between 2013 and 2014. Emergent cases, fracture cases, and preoperative compromised wounds were not analyzed. Primary thirty-day outcomes included mortality, return to operating room, readmission, length of stay, and other major complications. Minor outcomes included urinary tract infection, superficial incisional site infection, and perioperative blood transfusion within 72 hours.

RESULTS

ALIF/DLIF was performed more for degenerative lumbar disc disease (31.0% vs. 13.9%, P<0.001), whereas PLIF/TLIF was utilized more for spondylolisthesis (19.1% vs. 24.4%, P<0.001). Thirty-day mortality was significantly higher with ALIF/DLIF (0.3% vs. 0.1%, P=0.021) in the univariate analysis and persisted in the multivariate analysis (OR =12.8; 95% CI, 1.37-119.6; P=0.025). Significantly more PLIF/TLIF patients required blood transfusions within 72 hours of surgery (9.6% vs. 7.6%, P=0.005). This difference did not persist in the multivariate analysis after controlling for covariates. Elevated ASA physical status classification, age >60, prior bleeding disorder, and preoperative anemia were significantly associated with blood transfusion requirement. More deep venous thrombosis occurred (DVT) with ALIF/DLIF compared to PLIF/TLIF (1.0% vs. 0.6%, P=0.025), which persisted in the multivariate analysis (OR =2.03; 95% CI, 1.13-3.65; P=0.017).

CONCLUSIONS

Although numerous techniques can be utilized in the treatment approach to various lumbar pathologies, anterior approaches have an increased risk of developing a perioperative DVT and early mortality. Transfusion risk is more strongly associated with elevated American Society of Anesthesiologists (ASA) class, increased age, preoperative anemia, and patients with bleeding disorders.

Stem Cells in Spinal Fusion

STUDY DESIGN

Review of literature.

OBJECTIVES

This review of literature investigates the application of mesenchymal stem cells (MSCs) in spinal fusion, highlights potential uses in the development of bone grafts, and discusses limitations based on both preclinical and clinical models.

METHODS

A review of literature was conducted looking at current studies using stem cells for augmentation of spinal fusion in both animal and human models.

RESULTS

Eleven preclinical studies were found that used various animal models. Average fusion rates across studies were 59.8% for autograft and 73.7% for stem cell-based grafts. Outcomes included manual palpation and stressing of the fusion, radiography, micro-computed tomography (μCT), and histological analysis. Fifteen clinical studies, 7 prospective and 8 retrospective, were found. Fusion rates ranged from 60% to 100%, averaging 87.1% in experimental groups and 87.2% in autograft control groups.

CONCLUSIONS

It appears that there is minimal clinical difference between commercially available stem cells and bone marrow aspirates indicating that MSCs may be a good choice in a patient with poor marrow quality. Overcoming morbidity and limitations of autograft for spinal fusion, remains a significant problem for spinal surgeons and further studies are needed to determine the efficacy of stem cells in augmenting spinal fusion.

Correction of severe spinopelvic mismatch: decreased blood loss with lateral hyperlordotic interbody grafts as compared with pedicle subtraction osteotomy

OBJECTIVE

Pedicle subtraction osteotomy (PSO) provides extensive correction in patients with fixed sagittal plane imbalance but is associated with high estimated blood loss (EBL). Anterior column realignment (ACR) with lateral graft placement and sectioning of the anterior longitudinal ligament allows restoration of lumbar lordosis (LL). The authors compare peri- and postoperative measures in 2 groups of patients undergoing correction of a sagittal plane imbalance, either through PSO or the use of lateral lumbar fusion and ACR with hyperlordotic (20°–30°) interbody cages, with stabilization through standard posterior instrumentation in all cases.

METHODS

The authors performed a retrospective chart review of cases involving a lumbar PSO or lateral lumbar interbody fusion and ACR (LLIF-ACR) between 2010 and 2015 at the authors’ institution. Patients who had a PSO in the setting of a preexisting fusion that spanned more than 4 levels were excluded. Demographic characteristics, spinopelvic parameters, EBL, operative time, and LOS were analyzed and compared between patients treated with PSO and those treated with LLIF-ACR.

RESULTS

The PSO group included 14 patients and the LLIF-ACR group included 13 patients. The mean follow-up was 13 months in the LLIF-ACR group and 26 months in the PSO group. The mean EBL was significantly lower in the LLIF-ACR group, measuring approximately 50% of the mean EBL in the PSO group (1466 vs 2910 ml, p < 0.01). Total LL correction was equivalent between the 2 groups (35° in the PSO group, 31° in the LLIF-ACR group, p > 0.05), as was the preoperative PI-LL mismatch (33° in each group, p > 0.05) and the postoperative PI-LL mismatch (< 1° in each group, p = 0.05). The fusion rate as assessed by the need for reoperation due to pseudarthrosis was lower in the LLIF-ACR group but not significantly so (3 revisions in the PSO group due to pseudarthrosis vs 0 in the LLIF-ACR group, p > 0.5). The total operative time and LOS were not significantly different in the 2 groups.

CONCLUSIONS

This is the first direct comparison of the LLIF-ACR technique with the PSO in adult spinal deformity correction. The study demonstrates that the LLIF-ACR provides equivalent deformity correction with significantly reduced blood loss in patients with a previously unfused spine compared with the PSO. This technique provides a powerful means to avoid PSO in selected patients who require spinal deformity correction.

Clinical outcomes after minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion for treatment of degenerative lumbar disease: a systematic review and meta-analysis

The surgical procedures used for arthrodesis in the lumbar spine for degenerative lumbar diseases remain controversial. This systematic review aims to assess and compare clinical outcomes along with the complications and fusion of each technique (minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or minimally invasive lateral lumbar interbody fusion (MIS LLIF)) for treatment of degenerative lumbar diseases. Relevant studies were identified from Medline and Scopus from inception to July 19, 2016 that reported Oswestry Disability Index (ODI), back and leg pain visual analog score (VAS), postoperative complications, and fusion of either technique. Fifty-eight studies were included for the analysis of MIS-TLIF; 40 studies were included for analysis of LLIF, and 1 randomized controlled trial (RCT) study was included for comparison of MIS-TLIF to LLIF. Overall, there were 9506 patients (5728 in the MIS-TLIF group and 3778 in the LLIF group). Indirect meta-analysis, MIS-TLIF provided better postoperative back and leg pain (VAS), disabilities (ODI), and risk of having complications when compared to LLIF technique, but the fusion rate was not significantly different between the two techniques. However, direct meta-analysis between RCT study and pooled indirect meta-analysis of MIS-TLIF have better pain, disabilities, and complication but no statistically significant difference when compared to LLIF. In LLIF, the pooled mean ODI and VAS back pain were 2.91 (95% CI 2.49, 3.33) and 23.24 (95% CI 18.96, 27.51) in MIS approach whereas 3.14 (95% CI 2.29, 4.04) and 28.29 (95% CI 21.92, 34.67) in traditional approach. In terms of complications and fusion rate, there was no difference in both groups. In lumbar interbody fusion, MIS-TLIF had better ODI, VAS pain, and complication rate when compared to LLIF with direct and indirect meta-analysis methods. However, in terms of fusion rates, there were no differences between the two techniques.

Comparison of complication rates of minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion: a systematic review of the literature

OBJECT Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and lateral lumbar interbody fusion (LLIF) are 2 currently popular techniques for lumbar arthrodesis. The authors compare the total risk of each procedure, along with other important complication outcomes. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies (up to May 2015) that reported complications of either MI-TLIF or LLIF were identified from a search in the PubMed database. The primary outcome was overall risk of complication per patient. Secondary outcomes included risks of sensory deficits, temporary neurological deficit, permanent neurological deficit, intraoperative complications, medical complications, wound complications, hardware failure, subsidence, and reoperation. RESULTS Fifty-four studies were included for analysis of MI-TLIF, and 42 studies were included for analysis of LLIF. Overall, there were 9714 patients (5454 in the MI-TLIF group and 4260 in the LLIF group) with 13,230 levels fused (6040 in the MI-TLIF group and 7190 in the LLIF group). A total of 1045 complications in the MI-TLIF group and 1339 complications in the LLIF group were reported. The total complication rate per patient was 19.2% in the MI-TLIF group and 31.4% in the LLIF group (p < 0.0001). The rate of sensory deficits and temporary neurological deficits, and permanent neurological deficits was 20.16%, 2.22%, and 1.01% for MI-TLIF versus 27.08%, 9.40%, and 2.46% for LLIF, respectively (p < 0.0001, p < 0.0001, p = 0.002, respectively). Rates of intraoperative and wound complications were 3.57% and 1.63% for MI-TLIF compared with 1.93% and 0.80% for LLIF, respectively (p = 0.0003 and p = 0.034, respectively). No significant differences were noted for medical complications or reoperation. CONCLUSIONS While there was a higher overall complication rate with LLIF, MI-TLIF and LLIF both have acceptable complication profiles. LLIF had higher rates of sensory as well as temporary and permanent neurological symptoms, although rates of intraoperative and wound complications were less than MI-TLIF. Larger, prospective comparative studies are needed to confirm these findings as the current literature is of relative poor quality.