A comparison of posterior lumbar interbody fusion and transforaminal lumbar interbody fusion: a literature review and meta-analysis

Minimally Invasive versus Traditional Surgery: Efficacy of PELD and PLIF in Treating Pyogenic Spondylodiscitis

BACKGROUND Pyogenic spondylodiscitis is infection of the intervertebral disc or discs and the adjacent vertebrae. This retrospective study aimed to compare the effectiveness of percutaneous endoscopic lumbar debridement (PELD) versus posterior lumbar interbody fusion (PLIF) in 40 patients with pyogenic spondylodiscitis (PSD). MATERIAL AND METHODS Medical records of patients who underwent PELD (n=18) or PLIF (n=22) for PSD between 2018 and 2023 were reviewed. The recorded outcomes encompassed surgical duration, intraoperative blood loss, Oswestry Disability Index (ODI) measurements, Visual Analog Scale (VAS) assessments, C-reactive protein (CRP) levels, duration of hospitalization, erythrocyte sedimentation rate (ESR), American Spinal Injury Association (ASIA) grading, lumbar sagittal parameters, and the incidence of complications. RESULTS The PELD group had shorter surgical duration, less intraoperative blood loss, and shorter length of hospital stay compared to the PLIF group (P<0.01). At the last follow-up, both groups had significant improvement in ESR, CRP levels, and ASIA classification (P<0.001), but there was no significant difference between the 2 groups (P>0.05). The PELD group had lower ODI and VAS ratings at 1 month and 3 months, respectively (P<0.01). The PLIF group had significant improvements in intervertebral space height and lumbar lordosis angle (P<0.01). CONCLUSIONS Both PLIF and PELD surgical approaches demonstrate adequate clinical efficacy in the treatment of monosegmental PSD. PLIF can better ensure more spinal stability than PELD, but PELD offers advantages such as reduced minimal surgical trauma, shorter operative duration, and faster recovery after surgery.

Comparison of ALIF and PLIF in Isthmic Lumbosacral Spondylolisthesis. A Multicenter Surveillance Study of 602 cases from the German Spine Registry (DWG Register)

BACKGROUND

 Isthmic spondylolisthesis most commonly occurs in the lumbosacral junction and can cause backpain and radicular pain as well as stiffness with progressive immobilization, with a negative impact on an individual's ability to work and quality of life. Multiple operative treatments are currently available. This study aims to compare complications, demography, and clinical features between anterior lumbar interbody fusion (ALIF) and posterior lumber body fusion (PLIF) in the operative treatment in isthmic spondylolisthesis.

METHODS

 An analysis of data from the German spine registry (Deutsche Wirbelsäulengesellschaft [DWG]-Register) of patients who underwent operative treatment (PLIF and ALIF) for isthmic spondylolisthesis in the sacrolumbar junction in 170 departments between January 2017 and May 2021 was performed. Age, gender, American Society of Anesthesiologists (ASA) score, surgical approach, smoker/nonsmoker, as well as severeness of the spondylolisthesis according to the Meyerding classification were evaluated.

RESULTS

 In total, 602 patients undergoing fusion in L5/S1 were identified in the registry, n = 570 PLIF (group 1) and n = 32 ALIF (group 2). A significant difference in the ASA score between the two groups was noted; group 1 had more patients suffering a more debilitating disease in comparison to group 2. There was no significant difference in gender, grade of spondylolisthesis, age, or smoking status. Significant differences were found in operative and postoperative variables and complications (fusion material, dura injury).

CONCLUSION

 No difference was found between the two procedures in terms of symptomatic benefit of patients who underwent either ALIF or PLIF. According to the DWG Register, PLIF was the preferred method to treat isthmic spondylolisthesis in the sacrolumbar junction in Germany. To compare these two spine fusion techniques, further studies with an adequate sample size and follow-up period are required.

Load distribution on intervertebral cages with and without posterior instrumentation

BACKGROUND CONTEXT

Posterior and transforaminal lumbar interbody fusion (PLIF, TLIF) are well-established procedures for spinal fusion. However, little is known about load sharing between cage, dorsal construct, and biological tissue within the instrumented lumbar spine.

PURPOSE

The aim of this study was to quantify the forces acting on cages under axial compression force with and without posterior instrumentation.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

Ten lumbar spinal segments were tested under uniaxial compression using load cell instrumented intervertebral cages. The force was increased in 100N increments to 1000N or a force greater than 500N on one load cell. Each specimen was tested after unilateral PLIF (uPLIF), bilateral PLIF (bPLIF) and TLIF each with/without posterior instrumentation. Dorsal instrumentation was performed with 55N of compression per side.

RESULTS

Cage insertion resulted in median cage preloads of 16N, 29N and 35N for uPLIF, bPLIF, and TLIF. The addition of compressed dorsal instrumentation increased the median preload to 224N, 328N, and 317N, respectively. With posterior instrumentation, the percentage of the external load acting on the intervertebral cage was less than 25% at 100N (uPLIF: 14.2%; bPLIF: 16%; TLIF: 11%), less than 45% at 500N (uPLIF: 31.8%; bPLIF: 41.1%; TLIF: 37.9%) and less than 50% at 1000N (uPLIF: 40.3%; bPLIF: 49.7%; TLIF: 43.4%). Without posterior instrumentation, the percentage of external load on the cages was significantly higher with values above 50% at 100N (uPLIF: 55.6%; bPLIF: 75.5%; TLIF: 66.8%), 500N (uPLIF: 71.7%; bPLIF: 79.2%; TLIF: 65.4%), and 1000N external load (uPLIF: 73%; bPLIF: 80.5%; TLIF: 66.1%). For absolute loads, preloads and external loads must be added together.

CONCLUSIONS

Without posterior instrumentation, the intervertebral cages absorb more than 50% of the axial load and the load distribution is largely independent of the loading amplitude. With posterior instrumentation, the external load acting on the cages is significantly lower and the load distribution becomes load amplitude dependent, with a higher proportion of the load transferred by the cages at high loads. The bPLIF cages tend to absorb more force than the other two cage configurations.

CLINICAL SIGNIFICANCE

Cage instrumentation allows some of the compression force to be transmitted through the cage to the screws below, better distributing and reducing the overall force on the pedicle screws at the end of the construct and on the rods.

Do TLIF and PLIF Techniques Differ in Perioperative Complications? - Comparison of Complications Rates of Two High Volume Centers

STUDY DESIGN

Retrospective bicentric Cohort Study.

OBJECTIVE

Posterior (PLIF) and transforaminal lumbar interbody fusion (TLIF) have been clinically proven for the surgical treatment of degenerative spinal disorders. Despite many retrospective studies, the superiority of either technique has not been proven to date. In the literature, the complication rate of the conventional PLIF technique is reported to be significantly higher, but with inconsistent complication recording. In this retrospective bicentric study, a less invasive PLIF technique was compared with the conventional TLIF technique and complications were recorded using the validated SAVES V2 classification system.

METHODS

1142 patients underwent PLIF (702) or TLIF (n = 440) up to 3 levels in two specialized centers. Epidemiological data, intra- and postoperative complications during hospitalization and after discharge were analyzed according to SAVES V2.

RESULTS

The overall complication rate was 13.74%. TLIF-patients had slightly significant more complications than PLIF-patients (TLIF = 16.6%/PLIF = 11.9%, P = .0338). Accordingly, complications during revision surgeries were more frequent in the first cohort (TLIF = 20.9%/PLIF = 12.6%; P = .03252). In primary interventions, the surgical technique did not correlate with the complication rate (TLIF = 12.4%/PLIF = 11.7%). There were no significant differences regarding severity of complications.

CONCLUSIONS

An important component of this work is the complication recording according to a uniform classification system (SAVES V2). In contrast to previous literature, we could demonstrate that there is not a significant difference between the two surgical techniques.

Evolution of the Transforaminal Lumbar Interbody Fusion (TLIF): From Open to Percutaneous to Patient-Specific

The transforaminal lumbar interbody fusion (TLIF) has seen significant evolution since its early inception, reflecting advancements in surgical techniques, patient safety, and outcomes. Originally described as an improvement over the posterior lumbar interbody fusion (PLIF), the TLIF began as an open surgical procedure, that notably reduced the need for the extensive neural retractation that hindered the PLIF. In line with the broader practice of surgery, trending toward minimally invasive access, the TLIF was followed by the development of the minimally invasive TLIF (MIS-TLIF), a technique that further decreased tissue trauma and postoperative complications. Subsequent advancements, including Trans-Kambin's Triangle TLIF (percLIF) and transfacet LIF, have continued to refine surgical access, minimize surgical footprint, and reduce the risk of injury to the patient. The latest evolution, as we will describe it, the patient-specific TLIF, is a culmination of the aforementioned adaptations and incorporates advanced imaging and segmentation technologies into perioperative planning, allowing surgeons to tailor approaches based on individual patient anatomy and pathology. These developments signify a shift towards more precise methods in spine surgery. The ongoing evolution of the TLIF technique illustrates the dynamic nature of surgery and emphasizes the need for continued adaptation and refinement.

Evaluation of the efficacy and safety of percutaneous transforaminal endoscopic discectomy for multi-segmental lumbar disc herniation

Objective

To investigate the clinical efficacy and safety of percutaneous transforaminal endoscopic discectomy (PTED) in the treatment of multi-segmental lumbar disc herniation (msLDH).

Methods

From January 2021 to December 2021, 75 patients with msLDH admitted to Baoding No.1 Hospital of Traditional Chinese Medicine were selected and divided into PTED group (n=40) and posterior lumbar interbody fusion (PLIF) group (n=35) according to different surgical methods. The operative time, intraoperative blood loss, surgical complications, Oswestry disability index (ODI) and Japanese Orthopedic Association score (JOA) scores were compared between the two groups.

Results

In the PTED group, the average operation time was 57.45±12.01minutes, and the average intraoperative blood loss was 50.57±16.69ml. There were three patients with surgical complications, including one case of hematoma, one case of aggravation of neurological symptoms and one case of new onset of neurological symptoms. In the PLIF group, there were 12 cases undergoing single-segment operation, 15 cases undergoing double-segment operation and 8 cases undergoing three-segment operation, the average operation time was 137.26±34.64minutes, and the average intraoperative blood loss was 456.06±33.06ml, there were four cases of wound fat liquefaction or delayed healing, two cases of hematoma, and three cases of exacerbation of original neurological symptoms or new neurological symptoms. At one month, six months, and one year of postoperative, the ODI and JOA scores of the two groups were significantly improved compared with those preoperative, and the ODI scores of the PTED group were better than those of the PLIF group (t=3.131, 2.263, 3.768, all P<0.05).

Conclusion

The surgical effect of PTED in the treatment of LDH is similar to that of PLIF. However, PTED has the advantages of short operation time, less blood loss, fewer surgical complications, and high surgical safety. It is worthy of clinical promotion.

Comparison of the total and hidden blood loss in patients undergoing single-level open and unilateral biportal endoscopic transforaminal lumbar interbody fusion: a retrospective case control study

PURPOSE

This study aimed to compare total blood loss (TBL) and hidden blood loss (HBL) in patients undergoing single-level open transforaminal lumbar interbody fusion (O-TLIF) and unilateral biportal endoscopic transforaminal lumbar interbody fusion (ULIF).

METHODS

A total of 53 patients who underwent ULIF and 53 patients who underwent O-TLIF from March 2020 to July 2022 were retrospectively reviewed. The Nadler's formula was employed to estimate the patient's blood volume (PBV), Gross's formula to estimate TBL, and Sehat's formula to estimate HBL. The obtained data were then analyzed with independent t test, chi-squared test, and analysis of covariance.

RESULTS

TBL and measured blood loss (MBL) in ULIF group (326.86 ± 223.45 ml, 99.00 ± 72.81 ml) was significantly lower than O-TLIF group (427.97 ± 280.52 ml, 270.66 ± 102.34 ml). Nevertheless, the HBL in ULIF group was higher than that in O-TLIF group (227.86 ± 221.75 ml vs 157.31 ± 268.08 ml), however this was not statistically significant (p = 0.143). The HBL was 69.71 ± 23.72% of TBL in ULIF group and 36.76 ± 18.79% of TBL in O-TLIF group. Patients in ULIF group had lower TBL and MBL, shorter duration of drainage, lower postoperative anemia, and shorter postoperative hospital stay compared to those in O-TLIF group.

CONCLUSIONS

Perioperative HBL should not be neglected in patients undergoing ULIF or O-TILF, as it accounts for a large percentage of TBL in both groups. ULIF is associated with lower TBL and MBL, postoperative anemia, shorter postoperative hospital stays compared with O-TLIF.

Surgical techniques in restoration lumbar lordosis: a biomechanical human cadaveric study

PURPOSE

Degenerative changes of the lumbar spine lead in general to decrease of lumbar lordosis (LL). This change affects the overall balance of the spine, and when surgery is deemed, necessary restoration of the LL is considered. How this restoration can be achieved is a matter of controversy. The main purpose of this cadaveric study was to investigate the different steps of common posterior surgical techniques to understand the contribution of each successive step in restoring LL.

METHODS

Ten fresh-frozen human lumbar spine specimens were used to perform a sequential correction and instrumentation with a pedicle screw construct.

RESULTS

The mean LL angle measured at L3-L4 in intact condition was 12.9°; after screw insertion and compression, this increased to 13.8° (+ 7%, p = 0.04), after bilateral facetectomy to 16.3° (+ 20%, p = 0.005), after discectomy and insertion of interbody cage to 18.0º (+ 9%, p = 0.012), after resection of the lamina and the processes spinosus to 19.8° (+ 10%, p = 0.017), and after resection of the anterior longitudinal ligament to 25.4° (+ 22%, p = 0.005).

CONCLUSIONS

Each step contributed statistically significant to restoration of segmental lordosis with bilateral facetectomy contributing the most in terms of percentage.

LEVEL OF EVIDENCE

IV.

Patient reported outcomes after navigated minimally invasive hybrid lumbar interbody fusion (nMIS-HLIF) using cortical bone trajectory screws

Prospective observational study. To evaluate patient-reported outcomes after navigation-guided minimally invasive hybrid lumbar interbody fusion (nMIS-HLIF) for decompression and fusion in degenerative spondylolisthesis (Meyerding grade I-II). Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) are well-known standard procedures for lumbar spinal fusion. nMIS-HLIF is a navigation-guided combined percutaneous and open procedure that combines the advantages of PLIF and TLIF procedures for the preparation of a single-port endoscopic approach. 33 patients underwent nMIS-HLIF. Core outcome measure index (COMI), oswestry disability index (ODI), numeric rating scale (NRS) back, NRS leg, and short form health-36 (SF-36) were collected preoperatively and at follow-up of 6 weeks, 3 months, 6 months, and 1 year. The impact of body mass index (BMI) was also analyzed. Computed tomography reconstruction was used to assess realignment and verify fused facet joints and vertebral bodies at the 1-year follow-up. 28 (85%) completed the 1-year follow-up. The median BMI was 27.6 kg/m2, age 69 yrs. The mean reduction in listhesis was 8.4% (P < .01). BMI was negatively correlated with listhesis reduction (P = .032). The improvements in the NRS back, NRS leg, ODI, and COMI scores were significant at all times (P < .001-P < .01). The SF-36 parameters of bodily pain, physical functioning, physical component summary, role functioning/physical functioning, and social functioning improved (P < .003). The complication rate was 15.2% (n = 5), with durotomy (n = 3) being the most frequent. To reduce the complication rate and allow transitioning to a fully endoscopic approach, expandable devices have been developed. The outcomes of nMIS-HLIF are comparable to the current standard open and minimally invasive techniques. A high BMI hinders this reduction. The nMIS-HLIF procedure is appropriate for learning minimally invasive dorsal lumbar stabilization. The presented modifications will enable single-port endoscopic lumbar stabilization in the future.

Lumbar Interbody Fusion and Osteobiologics for Lumbar Fusion

Lumbar interbody fusion (LIF) is an excellent treatment option for a number of lumbar diseases. LIF can be performed through posterior, transforaminal, anterior, and lateral or oblique approaches. Each technique has its own pearls and pitfalls. Through LIF, segmental stabilization, neural decompression, and deformity correction can be achieved. Minimally invasive surgery has recently gained popularity and each LIF procedure can be performed using minimally invasive techniques to reduce surgery-related complications and improve early postoperative recovery. Despite advances in surgical technology, surgery-related complications after LIF, such as pseudoarthrosis, have not yet been overcome. Although autogenous iliac crest bone graft is the gold standard for spinal fusion, other bone substitutes are available to enhance fusion rate and reduce complications associated with bone harvest. This article reviews the surgical procedures and characteristics of each LIF and the osteobiologics utilized in LIF based on the available evidence.

Clinical Effect of Minimally Invasive Microendoscopic-Assisted Transforaminal Lumbar Interbody Fusion for Single-Level Lumbar Disc Herniation

OBJECTIVE

This retrospective study aimed to compare the clinical and radiological outcomes of transforaminal lumbar interbody fusion (TLIF) through the Wiltse approach (W-TLIF) vs minimally invasive microendoscopy-assisted transforaminal lumbar interbody fusion (ME-TLIF) in single-segment lumbar disc herniation (LDH).

METHODS

A retrospective study was conducted to study the differences in specific clinical outcomes between single-segment LDH patients receiving W-TLIF and ME-TLIF. Single-segment LDH patients admitted to the Fujian Medical University Union Hospital from March 2015 to June 2018 were included. All the participants were divided into the ME-TLIF group or the W-TLIF group according to their TLIF surgery types. Demographic characteristics, the visual analog score (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) scale, blood loss volume, postoperative drainage, ambulated time, initial postoperative back pain, hospitalization duration, expenses, and improvement rates of patients in the two groups were collected for analysis. Radiographic fusion was ultimately assessed via the Bridwell interbody fusion grading system. All selected patients with TLIF were followed up for 1 year.

RESULTS

Fifty-seven patients were selected, with 26 in the ME-TLIF group and 31 in the W-TLIF group, both of whom were followed up for 1 year. The mean age of the included patients was 53.75 ± 9.313 years, and the sex ratio was indiscrimination. There was no significant difference in demographic data or operating time between the two groups prior to surgery. The blood loss volume (ME-TLIF: 228.5 vs W-TLIF: 681.3), postoperative drainage (ME-TLIF:82.1 ± 23.5 vs W-TLIF: 345.8 ± 65.2), initial postoperative back pain (ME-TLIF: VAS_3 days: 1.96 ± 0.60 VAS_7 days: 1.73 ± 0.53, W-TLIF: VAS_3 days: 2.48 ± 0.51 VAS_7 days: 1.87 ± 0.43), and hospitalization duration (ME-TLIF: 9.04 vs. W-TLIF: 11.29) were all significantly lower in the ME-TILF group (p < 0.05). However, there were no statistical differences between the two groups in VAS, ODI, and JOA at 1 month, 3 months, 6 months, and 1 year postoperatively (p > 0.05). The fusion rates of the two groups showed no notable difference (p > 0.05), while the X-ray exposure time in the ME-TLIF group was significantly longer than in the W-TLIF group (p < 0.05).

CONCLUSIONS

ME-TLIF surgery was an effective and satisfactory surgical technique to manage LDH. Although ME-TLIF increased the operation time and intraoperative fluoroscopic irradiation volume, it could effectively relieve low back pain from early postoperative onset and promote early postoperative recovery compared with W-TLIF.

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.

Intraoperative Endplate Injury Following Transforaminal Lumbar Interbody Fusion

OBJECTIVE

To investigate the incidence, distribution characteristics, risk factors, and clinical outcomes of intraoperative endplate injury following transforaminal lumbar interbody fusion (TLIF).

METHODS

Patients who underwent single-level TLIF from January 2018 to December 2020 were included. The patients were separated into endplate injury group (EI group) and no endplate injury group (non-EI group) by postoperative computed tomography scanning immediately. All patients' demographic, clinical, and radiographic parameters were analysed. Clinical outcomes were evaluated by visual analogue scale (VAS) for low back pain and Oswestry Disability Index (ODI).

RESULTS

576 patients were enrolled in this study. The rates of endplate injury were 19.6% (113 of 576) of patients and 9.9% (114 of 1152) of endplates. The rate of superior endplate injury was significantly higher than that of inferior endplate injury. The results illustrated that older age, lower disc height index (DHI), and taller cage height were independent risk factors for intraoperative endplate injury. The postoperative drain output, total blood loss, postoperative duration of drainage tube, and postoperative hospital stay in EI group were significantly more than those in non-EI group. There were no statistical differences in ODI and VAS scores at the same time point between two groups.

CONCLUSIONS

The rates of endplate injury were 19.6% of patients and 9.9% of endplates. The superior endplates are more susceptible to injury than inferior endplates. Older age, lower DHI, and taller cage height were independent risk factors for intraoperative endplate injury. Clinical outcomes were not affected by intraoperative endplate injury during early postoperative follow-up.

Surgical Treatments for Lumbar Spine Diseases (TLIF vs. Other Surgical Techniques): A Systematic Review and Meta-Analysis

Objective

The purpose of this study is to compare fusion rate, clinical outcomes, complications among transforaminal lumbar interbody fusion (TLIF), and other techniques for lumbar spine diseases.

Design

This is a systematic review and meta-analysis.

Data Sources

PubMed, EMBASE, Scopus, Web of Science, and CENTRAL databases were searched from January 2013 through December 2019.

Eligibility Criteria for Selecting Studies

Randomized controlled trials (RCTs) that compare lumbar interbody fusion with posterolateral fusion (PLF) and/or other lumbar interbody fusion were included for the review.

Data Extraction and Synthesis

Two independent reviewers extracted relevant data and assessed the risk of bias. Meta-analysis was performed using a random-effects model. Pooled risk ratio (RR) or mean difference (MD) with a 95% confidence interval of fusion rate, clinical outcomes, and complications in TLIF and other techniques for lumbar spinal diseases.

Results

Of 3,682 potential studies, 15 RCTs (915 patients) were included in the meta-analysis. Compared to other surgical techniques, TLIF had slightly lower fusion rate [RR = 0.84 (95% CI = 0.72–0.97), p = 0.02, I² = 0.0%] at 1-year follow-up whereas there was no difference on fusion rate at 2-year follow-up [RR = 1.06 (95% CI = 0.96–1.18), p = 0.27, I² = 69.0%]. The estimated RR of total adverse events [RR = 0.90 (95% CI = 0.59–1.38), p = 0.63, I² = 0.0%] was similar to no fusion, PLF, PLIF, and XLIF groups, and revision rate [RR = 0.78 (95% CI = 0.34–1.79), p = 0.56, I² = 39.0%] was similar to PLF and XLIF groups. TLIF had approximately half an hour more operative time than other techniques (no fusion, ALIF, PLF, PLIF, XLIF) [MD = 31.88 (95% CI = 5.33–58.44), p = 0.02, I² = 92.0%]. There was no significant difference between TLIF and other techniques in terms of blood loss (no fusion, PLIF, PLF) and clinical outcomes (PLF).

Conclusions

Besides fusion rate at 1-year follow-up and operative time, TLIF has a similar fusion rate, clinical outcomes, parameters concerning operation and complications to no fusion, PLF, and other interbody fusion (PLIF, ALIF, XLIF).

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42020186858.

Clinical and radiological outcomes in patients who underwent posterior lumbar interbody fusion: comparisons between unilateral and bilateral cage insertion

BACKGROUND

Although the original technique involves inserting two cages bilaterally, there could be situations that only allow for insertion of one cage unilaterally. However, only a few studies have compared the outcomes between unilateral and bilateral cage insertion. The purpose of this study was to compare the clinical and radiological outcomes in patients who underwent posterior lumbar interbody fusion (PLIF) between unilaterally and bilaterally inserted cages.

METHODS

Among 206 eligible patients who underwent 1- or 2-level PLIF, 78 patients were 1:3 cohort-matched by age, sex, and operation level (group U, 19 patients with unilateral cages; and group B, 57 patients with bilateral cages). Fusion status was evaluated by computed tomography (CT) scans at postoperative 1 year. Clinical outcomes were measured by visual analog scale (VAS), Oswestry Disability Index (ODI), and EQ-5D. Radiological and clinical parameters were compared between the two groups. Risk factors for pseudarthrosis were also analyzed by multivariate analysis.

RESULTS

The demographic data were not significantly different between the two groups. However, previous laminectomy, asymmetric disc collapse, and fusion at L5-S1 level were more frequently found in group U (P = 0.003, P = 0.014, and P = 0.014, respectively). Furthermore, pseudarthrosis was more frequently observed in group U (36.8%) than in group B (7.0%) (P = 0.004). Back pain VAS was higher in group U at postoperative 1 year (P = 0.033). Lower general activity function of EQ-5D was observed in group U at postoperative 1 year (P = 0.035). Older age (P = 0.028), unilateral cage (P = 0.007), and higher bone mineral density (P = 0.033) were positively correlated with pseudarthrosis.

CONCLUSIONS

Unilaterally inserted cage might be a possible risk factor for pseudarthrosis when performing PLIF, which could be related with the difficult working conditions such as scars due to previous laminectomy or asymmetric disc collapse. Furthermore, suboptimal clinical outcomes are expected following PLIF with unilateral cage insertion at postoperative 1 year regardless of similar clinical outcomes at postoperative 2 year. Therefore, caution is advised when inserting cages unilaterally, especially under above-mentioned conditions in terms of its possible relationship with symptomatic pseudarthrosis.

Does the Choice of Spinal Interbody Fusion Approach Significantly Affect Adjacent Segment Mobility?

STUDY DESIGN

Biomechanical study of range of motion (ROM) at the vertebral levels adjacent to the construct of posterior pedicle screw-rod fixation with different types of lumbar interbody fusion techniques (LIF).

OBJECTIVE

To investigate the differences in adjacent segment mobility among three types of LIF: lateral lumbar interbody fusion (LLIF), transforaminal lumbar interbody fusion (TLIF), and posterior lumbar interbody fusion (PLIF).

SUMMARY OF BACKGROUND DATA

Previous studies have concluded that LLIF, TLIF, and PLIF with posterior pedicle screw-rod fixation (PSR) provide equivalent stability in cadaveric specimens and are comparable in fusion rate and functional outcome. However, long-term complications, such as adjacent segment degeneration associated with each type of interbody device, are currently unclear. Little is known about the biomechanical effects of interbody fusion technique on the mobility of adjacent segments.

METHODS

Normalized ROM data at the levels adjacent to L3-L4 PSR fixation with three different types of lumbar interbody fusion approaches (LLIF, TLIF, and PLIF) were analyzed. Intact (n = 21) and instrumented (n = 7 per group) L2-L5 cadaveric specimens were tested multidirectionally under pure moment loading (7.5 Nm). Analysis of variance of adjacent segment ROM among the groups was performed. Statistical significance was set at P < 0.05.

RESULTS

Normalized ROM was significantly greater with PLIF than with LLIF in all directions at both proximal and distal adjacent segments (P ≤ 0.02) except for axial rotation at the distal adjacent segment (P = 0.07). TLIF also had greater normalized ROM than LLIF during lateral bending at the proximal adjacent segment (P = 0.008) and during flexion, extension, and lateral bending at the distal adjacent segment (P ≤ 0.03). Normalized ROM was not significantly different between PLIF and TLIF.

CONCLUSION

The choice of lumbar interbody fusion approach influences adjacent segment motion in a cadaveric model. LLIF had the least adjacent segment motion.Level of Evidence: 3.

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

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

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

STUDY DESIGN

A network meta-analysis.

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Lordosis Restoration With Midline Minimally Invasive Cortical Trajectory Screws (MidLF) and Transforaminal Interbody Fusion: A Safe Technique With a Short Stay

BACKGROUND

The minimally invasive cortical trajectory screw (MidLF) technique has been described accompanied with posterolateral interbody fusion (PLIF). We present our 2-year results of a hybrid technique to show that using transforaminal interbody fusion (TLIF) rather than PLIF in conjunction with MidLF is a less invasive and safe technique.

METHODS

We retrospectively identified 25 patients who underwent MidLF with TLIF from July 2015 through September 2017. The surgical technique was the same for each, with radiological, clinical, and patient-reported outcome data collected and analyzed at a 2-year follow-up.

RESULTS

The cohort showed a mean age of 55 (35-85) years. The length of hospital stay was between 1 and 4 days, with an average of 2.7 days. Postoperatively, lordosis across the motion segment fused increased by a mean of 7.3° (0°-24°), mean pelvic incidence was 53°(31°-80°), and pelvic tilt reduced by an average of 3.5° (0°-11°). The Oswestry Disability Index improved from 34 preoperatively to 19 postoperatively. Visual analogue pain score-leg improved by 4.7 points, from 6 down to 1. One patient showed delayed wound healing. There were no incidences of neurological injury or durotomy.

CONCLUSIONS

Our data suggests that MidLF with TLIF is both less invasive than traditional techniques and safe. It restores lordosis, requires less exposure and retraction of neural elements than the more widely used PLIF, and shows early discharge and satisfactory medium-term patient-reported outcomes.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

The MidLF technique with PLIF is less invasive than traditional techniques, restores alignment and shows satisfactory medium term results.

Influence of Cage Design on Radiological and Clinical Outcomes in Dorsal Lumbar Spinal Fusions: A Comparison of Lordotic and Non-Lordotic Cages

Objectives

To evaluate the comparison between lordotic and non‐lordotic transforaminal lumbar interbody fusion (TLIF) cages in degenerative lumbar spine surgery and analyze radiological as well as clinical outcome parameters in long‐term follow up.

Methods

In a retrospective study design, we compared 37 patients with non‐lordotic cage (NL‐group) and 40 with a 5° lordotic cage (L‐group) implanted mono‐ or bi‐segmental in TLIF‐technique from 2013 to 2016 and analyzed radiological parameters of pre‐ and postoperative (Lumbar lordosis (LL), segmental lordosis (SL), and pelvic tilt (PT), as well as clinical parameters in a follow‐up physical examination using the Oswestry disability index (ODI), Roland–Morris Score (RMS), and visual analog scale (VAS).

Results

Surgery was mainly performed in lower lumbar spine with a peak in L4/5 (mono‐segmental) and L4 to S1 (bi‐segmental), long‐term follow‐up was on average 4 years postoperative. According to the literature, we found significantly better results in radiological outcome in the L‐group compared to the NL‐group: LL increased 6° in L‐group (51° preoperative to 57° postoperative) and decreased 1° in NL‐group (50° to 49° (P < 0.001). Regarding SL, we found an increase of 5° in L‐group (13° to 18°) and no difference in NL‐group (15°)(P < 0.001). In PT, we found a clear benefit with a decrease of 2° in L‐group (21° to 19°) and no difference in NL‐group (P = 0.008).

In direct group comparison, ODI in NL‐group was 23% vs 28% in L‐group (P = 0.25), RMS in NL‐group was 8 points vs 9 points in L‐group (P = 0.48), and VAS was in NL‐group 2.7 vs 3.2 in L‐group (P = 0.27) without significant differences.

However, the clinical outcome in multivariate analysis indicated a significant multivariate influence across ODI and RMS of BMI (Wilks λ = 0.57, F [4, 44] = 3.61, P = 0.012) and preoperative SS (Wilks λ = 0.66, F [4, 44] = 2.54, P = 0.048). Age, gender, cage type and postoperative PT had no significant influence (P > 0.05). Intraoperatively, we saw three dura injuries that could be sutured without problems and had no consequences for the patient. In the follow‐up, we did not find any material‐related problems, such as broken screws or cage loosening, also no pseudarthrosis.

Conclusion

In conclusion, we think it's not cage design but other influenceable factors such as correct indication and adequate decompression that lead to surgical success and the minimal difference in the LL therefore seemed to be of subordinate importance.

Posterior Lumbar Interbody Fusion Versus Transforaminal Lumbar Interbody Fusion: Finite Element Analysis of the Vibration Characteristics of Fused Lumbar Spine

OBJECTIVE

Previous studies have investigated biomechanical characteristics of the lumbar spine after different types of lumbar interbody fusion surgery under static loadings. However, very few have dealt with the whole-body vibration (WBV) condition that is typically present in vehicles. The aim of this study was to compare the influence of posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) on dynamic responses of the fused lumbar spine to vertical WBV.

METHODS

The PLIF and TLIF procedures with bilateral pedicle screw fixation at L4-L5 level were simulated by modifying a previously validated intact lumbar L1-S1 finite element model. The PLIF and TLIF models were subjected to a sinusoidal vertical load with a compressive follower preload, and computed for transient dynamic analysis. The obtained dynamic responses for the models at the fused and adjacent levels were collected and compared.

RESULTS

The results showed that the contact force between endplate and cage was higher in the PLIF model than in the TLIF model, indicating that PLIF allowed for higher compressive load across the anterior structure. At fused L4-L5 level, the TLIF led to a higher stress in the endplate and posterior BPSF system than the PLIF. At adjacent L3-L4 level and L5-S1 level, the computed dynamic responses, in terms of stress and deformation, for the PLIF and TLIF models showed very few differences.

CONCLUSIONS

This study may be helpful to quantify dynamic mechanical properties of the fused lumbar spine, and better understand biomechanical differences between the PLIF and TLIF procedures during vibration.

Robot-Guided Transforaminal Versus Robot-Guided Posterior Lumbar Interbody Fusion for Lumbar Degenerative Disease

Objective

There have been no clinical studies comparing different robotic techniques. We compare minimally invasive, robot-guided transforaminal lumbar interbody fusion (RG-TLIF) and mini-open robot-guided posterior lumbar interbody fusion (RG-PLIF).

Methods

Using data from a prospective institutional registry, we identified 38 patients who underwent RG-PLIF. Propensity score matching using a nearest-neighbor algorithm was implemented to select RG-TLIF controls. Twelve-month patient-reported outcome measures are presented. A reduction of ≥ 30% from baseline was defined as the minimum clinically important difference (MCID).

Results

Among the 76 included patients, there was no difference between RG-TLIF and RG-PLIF in surgical time (132.3 ± 29.4 minutes vs. 156.5 ± 53.0 minutes, p = 0.162), length of stay (55.9 ± 20.0 hours vs. 57.2 ± 18.8 hours, p = 0.683), and radiation dose area product (310.6 ± 126.1 mGy × cm² vs. 287.9 ± 90.3 mGy × cm², p = 0.370). However, while there was no difference among the 2 groups in terms of raw postoperative patient-reported outcome measures scores (all p > 0.05), MCID in leg pain was greater for RG-PLIF (55.3% vs. 78.9%, p = 0.028), and MCID in Oswestry Disability Index was greater for RG-TLIF (92.1% vs. 68.4%, p = 0.009). There was no difference concerning back pain (81.6% vs. 68.4%, p = 0.185).

Conclusion

Our findings suggest that both RG-TLIF and RG-PLIF are viable and equally effective techniques in robotic spine surgery.

Prone Transpsoas Technique for Simultaneous Single-Position Access to the Anterior and Posterior Lumbar Spine

BACKGROUND

Effective decompression, arthrodesis, and correction of spinal conditions frequently utilize operative approaches that expose both the anterior and posterior spinal column. Until now, circumferential spinal column access often requires the surgeon to reposition and drape the patient multiple times or utilize a posterior only approach that has limited anterior correction capability or to utilize a lateral-only approach that complicates otherwise traditional posterior surgical maneuvers.

OBJECTIVE

To describe a technique utilizing a single surgical position that enables minimally disruptive anterior column correction with simultaneous access to the posterior spinal column.

METHODS

The operative technique for accessing the lateral lumbar interbody space from a prone transpsoas (PTP) approach is described. The rationale for this approach and a representative case example are reviewed.

RESULTS

The PTP approach was used to perform an L3-4 and L4-5 interbody fusion in a 71-yr-old female with spondylolisthesis, severe stenosis, and locked facets. The PTP approach enabled efficient completion of an anterior column correction, direct posterior decompression, multi-segment pedicle fixation, and maintenance of alignment, all while in a single prone position. There were no intraoperative or postoperative complications.

CONCLUSION

The authors’ early experience with the described PTP technique suggests it is not only feasible but offers some advantages, as it allows for single-position surgery maximizing both anterior and posterior column access and corrective techniques. Further follow-up studies of this technique are ongoing.

Lumbar Interbody Fusion: Techniques, Pearls and Pitfalls

Lumbar interbody fusion (LIF) is an effective and popular surgical procedure for the management of various spinal pathologies, especially degenerative diseases. Currently, LIF can be performed with posterior, transforaminal, anterior, and lateral approaches by open surgery or minimally invasive surgery (MIS). Each technique has its own advantages and disadvantages. In general, posterior LIF is a well-established procedure with good fusion rates and low complication rates but is limited by the possibility of iatrogenic injury to the neural structures and paraspinal muscles. Transforaminal LIF is frequently performed using an MIS technique and has an advantage of reducing these iatrogenic injuries. Anterior LIF (ALIF) can restore the disk height and sagittal alignment but has inherent approach-related challenges such as visceral and vascular complications. Lateral LIF and oblique LIF are performed using an MIS technique and have shown postoperative outcomes similar to ALIF; however, these approaches carry a risk of injury to psoas, lumbar plexus, and vascular structures. Herein, we provide a detailed description of the surgical procedures of each LIF technique. We shall then consider the pearls and pitfalls, as well as propose surgical indications and contraindications based on the available evidence in the literatures.

Clinical, radiological and functional results of transforaminal lumbar interbody fusion in degenerative spondylolisthesis

Purpose

To evaluate the clinical, functional and radiographic outcomes of transforaminal lumbar interbody fusion (TLIF) in degenerative low-grade spondylolisthesis.

Materials and Methods

A prospective observational study of 120 consecutive patients (M:F = 24:96) with spondylolisthesis operated with TLIF. Clinical and functional outcome was assessed on Visual analogue Scale (VAS) and Oswestry Disability Index(ODI). The radiological outcome was assessed on sagittal alignment at a specific level, radiologic bony fusion/non-union, intervertebral disc heights and percentage of a slip in relation to the endplate. Clinical and radiological data were collected and analysed.

Results

The mean age was 50.97 years. The average follow-up was 14.5 months (12 to 18 months). Mean preoperative ODI was 38.73 and postoperatively 21.30. Analysing the radiological fusion with clinical scores, poorer radiological fusion grades correlated with higher VAS scores for pain. 70% of patients achieved >50% reduction in pain and 60% achieved > 30% reduction in ODI. Pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL) were significantly greater in spondylolisthesis. PI, PT, and SS did not change statistically from the baseline postoperatively but increased LL and Segmental LL (P < 0.001). The results of our study showed a close relation between satisfactory clinical outcome (90%) and solid fusion (80%). There was however a significant number of patients with instrument failure that was found in association with fusion failure. There were no intra-operative complications.

Conclusion

TLIF is an effective option to achieve circumferential fusion without severe complications. An increased pelvic incidence may be an important factor predisposing to progression in developmental spondylolisthesis. TLIF increases global and segmental LL and provides a satisfactory outcome in symptomatic low-grade degenerative spondylolisthesis.

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.

Comparison of Transforaminal Lumbar Interbody Fusion Using the Boomerang-Shaped Cage with Traditional Posterior Lumbar Interbody Fusion for Lumbar Spondylolisthesis

INTRODUCTION

This study aimed to compare the clinical and radiological results of transforaminal lumbar interbody fusion (TLIF) with a boomerang-shaped cage and traditional posterior lumbar interbody fusion (PLIF) according to fused level and elucidate whether TLIF could replace PLIF at all lumbar levels.

METHODS

The study investigated 128 patients with lumbar spondylolisthesis who underwent a single-level TLIF or traditional PLIF. Intraoperative blood loss, operative time, and recovery rate were analyzed. Percent slip, disc height, and local lordosis at the fused level were measured using X-ray images from preoperation to the final follow-up.

RESULTS

No significant differences in recovery rate were observed at any level. The operative time and intraoperative blood loss were significantly less in the TLIF group at the L4/5 and L5/S1 levels. There were no significant differences in disc height or local lordosis at the L3/4 and L4/5 levels, and a satisfactory level of maintenance after the operation was achieved in both groups. However, at the L5/S1 level, postoperative maintenance after TLIF could not be achieved, and the obtained disc height and local lordosis in TLIF significantly decreased.

CONCLUSIONS

Compared with traditional PLIF, TLIF was a less invasive procedure with a shorter operative time and lesser blood loss. TLIF could obtain similar local lordosis and disc height as PLIF at the L3/4 and L4/5 levels. At the L5/S1 level, the postoperative maintenance of local lordosis and disc height after TLIF was inferior to that after PLIF. On the basis of our results, we do not recommend performing TLIF at only the L5/S1 level.

Design and material evaluation for a novel lumbar disc replacement implanted via unilateral transforaminal approach

The degeneration of the intervertebral disc is one of the principal causes of low back pain. Total disc replacement is a surgical treatment that aims to replace the degenerated disc with a dynamic implant to restore spine biomechanics. This paper proposes the first design of an elastomeric lumbar disc replacement that is implanted as a pair of devices via unilateral transforaminal surgical approach. Furthermore, several biomaterials (Polyurethanes (PU) and Polycarbonate Urethanes (PCU)) are evaluated for the purpose of the implant to mimic the axial compliance of the spine. Bionate II 80A (a pure PCU), Elast Eon 82A E5-325 (a PU with polydimethylsiloxane and polyhexamethylene oxide), Chronosil (a PCU based silicone elastomer) 80A with 5% and 10% of silicone were obtained and injection moulded according to the shape of the implant core, which was defined after a stress distribution analysis with the finite element method. The dimensions for each specimen were: 14.6 × 5.6 × 6.1 mm (length, width and height). Quasistatic compression tests were performed at a displacement rate of 0.02 mm/s. The obtained stiffness for each material at 1 mm displacement was: Bionate II 80A, 448.48 N/mm; Elast Eon 82A E5-325, 216.55 N/mm; Chronosil 80A 5%, 127.73 N/mm; and Chronosil 80A 10%, 126.48 N/mm. Dimensional changes were quantified after two quasi-static compression tests. Plastic deformation was perceived in all cases with a total percentage of height loss of: 4.1 ± 0.5% for Elast Eon 82A E5-325; 3.2 ± 0.5% for Chronosil 80A 10%; 2.7 ± 0.3% for Chronosil 80A 5% and 1.1 ± 0.2% for Bionate II 80A. The mechanical behaviour of these biomaterials is discussed to assess their suitability for the novel disc replacement device proposed.

Anterior Versus Transforaminal Lumbar Interbody Fusion: Perioperative Risk Factors and 30-Day Outcomes

Background

Operative management of lower back pain often necessitates anterior lumbar interbody fusion (ALIF) or transforaminal lumbar interbody fusion (TLIF). Specific pathoanatomic advantages and indications exist for both approaches, and few studies to date have characterized comparative early outcomes.

Methods

Adult patients undergoing elective ALIF or TLIF operations were abstracted from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) years 2011-2014. Univariate analyses were performed by surgery cohort for each outcome and adjusted for demographic/clinical variables (age ≥ 65, sex, race, body mass index, American Society of Anesthesiologists physical classification score, functional status, inpatient/outpatient status, smoking, hypertension, Charlson Comorbidity Index) using multivariable regression. Means, standard errors, mean differences (B), odds ratios (ORs), and associated 95% confidence intervals (CIs) are reported. Significance was assessed at P < .05.

Results

Of 8263 subjects (ALIF: 4325, TLIF: 3938), ALIF subjects were younger, less obese, less physically impaired, and had significantly lower rates of hypertension, diabetes, coagulopathy, and previous cardiac surgery. On multivariable analysis, ALIF associated with shorter operative time (B = -11.80 minutes, 95% CI [-16.48, -7.12]; P < .001). Transforaminal lumbar interbody fusion was associated with increased incidence of urinary tract infections (UTIs; OR = 1.57, 95% CI [1.10, 2.26]; P = .013) and of blood transfusions (OR = 1.19, 95% CI [1.04, 1.37]; P = .012). Multivariate analysis also demonstrated TLIF associated with shorter hospital length of stay (B = -0.27 days, 95% CI [-0.54, -0.01]; P = .041), and fewer cases of pneumonia (OR = 0.55, 95% CI [0.32, 0.94]; P = .029) and prolonged ventilator dependency (OR = 0.33, 95% CI [0.12, 0.84]; P = .021).

Conclusions

Comparatively, ALIF patients experienced decreased operative time and decreased incidence of postoperative UTIs and blood transfusions. Anterior lumbar interbody fusion patients were more likely to suffer postoperative pulmonary complications and longer hospital stays. Our data support the notion that both anterior and transforaminal surgical approaches perform comparably in context of 30-day perioperative outcomes.

Postoperative Infection in Patients Undergoing Posterior Lumbosacral Spinal Surgery: A Pictorial Guide for Diagnosis and Early Treatment

Surgical site infections after posterior spinal surgery may lead to spondylodiscitis, pseudarthrosis, correction loss, adverse neurological sequelae, sepsis, and poor outcomes if not treated immediately. Infection rates vary depending on the type and extent of operative procedures, use of instrumentation, and patients' risk factors. Image evaluation is crucial for early diagnosis and should be complementary to clinical routes, laboratory survey, and treatment timing. Magnetic resonance imaging detects early inflammatory infiltration into the vertebrae and soft tissues, including hyperemic changes of edematous marrow, vertebral endplate, and abscess or phlegmon accumulation around the intervertebral disk, epidural, and paravertebral spaces. Aggressive surgical treatment can eradicate infection sources, obtain a stable wound closure, decrease morbidity, and restore spinal integrity. Organ/space infection is defined as any body parts opened to manipulate other than superficial/deep incision. Advanced magnetic resonance imaging evaluating abnormal fluid accumulation, heterogenous contrast enhancement of the endplate erosion due to cage/screw infection is categorized to inform a presumptive diagnosis for early implant salvage. However, patients' defense response, infection severity, bacteriology, treatment timing, spinal stability, and available medical and surgical options must be fully considered. Revision surgery is indicated for pseudarthrosis, implant loosening with correction loss, recalcitrant spondylodiscitis, and adjacent segment diseases for infection control.

Effect of PLIF and TLIF on sagittal spinopelvic balance of patients with degenerative spondylolisthesis

OBJECTIVE

The aim of this study was to evaluate the effects of PLIF and TLIF on sagittal spinopelvic balance and to compare radiological results of two surgical procedures with regard to spinopelvic parameters.

METHODS

Thirty-five patients (34 female and 1 male; mean age: 52.29 ± 13.08 (range: 35-75)) with degenerative spondylolisthesis cases were included in the study. Patients were divided into two groups according to surgical technique: PLIF and TLIF. The level and the severity of listhesis according to Meyerding classification were assessed and spinopelvic parameters including sacral slope, pelvic tilt, pelvic incidence (PI), lumbar lordosis, and segmental lumbar lordosis were measured on digital X-rays. All preoperative and postoperative parameters and the results were compared between two groups.

RESULTS

The age distribution was similar in both groups (p = 0.825) and there was no difference between the mean PI of the groups (p = 0.616). In 15 patients, spondylolisthesis level were at the L5-S1 level (PLIF: 8, TLIF: 7), in 16 patients at the L4-L5 level (PLIF: 6, TLIF: 10) and in 4 patients at the L3-L4 level (PLIF: 2, TLIF: 2). According to Meyerding classification, before the operation, the sliding grades were 0 in 4 patients, 1 in 21 patients, 2 in 7 patients, and 3 in 3 patients. The grades changed into 0 in 28 patients, 1 in 5 patients, and 2 in 2 patients after surgery. There were no differences in the grade of listhesis between PLIF and TLIF groups preoperatively (p = 0.190) and postoperatively (p = 0.208). In both groups, the spondylolisthesis-related deformities of patients were significantly corrected after surgery (p < 0.001).

CONCLUSION

PLIF and TLIF techniques have similar radiological results in restoring the sagittal spinopelvic balance in patients with degenerative spondylolisthesis. Both techniques are good options to achieve reduction and fusion in patients with degenerative spondylolisthesis, but have no advantage over each other for restoring spinopelvic balance.

LEVEL OF EVIDENCE

Level III, Therapeutic study.

Safety of a novel modular cage for transforaminal lumbar interbody fusion - clinical cohort study in 20 patients with degenerative disc disease

Introduction: Transforaminal lumbar interbody fusion (TLIF) is used to reconstruct disc height and reduce degenerative deformity in spinal fusion. Patients with osteoporosis are at high risk of TLIF cage subsidence; possibly due to the relatively small footprint compared to anterior interbody devices. Recently, modular TLIF cage with an integral rail and slot system was developed to reduce cage subsidence and allow early rehabilitation.

Objective: To study the safety of a modular TLIF device in patients with degenerative disc disorders (DDD) with regard to surgical complications, non-union, and subsidence.

Methods: Patients with DDD treated with a modular TLIF cage (Polyetheretherketone (PEEK), VTI interfuse S) were analysed retrospectively with one-year follow-up. Lumbar sagittal parameters were collected preoperatively, postoperatively and at one year follow-up. Cage subsidence, fusion rate, screw loosening and proportion of endplate coverage were assessed in computed tomography scan.

Results: 20 patients (age 66 ± 10 years, 65% female, BMI 28 ± 5 kg/m²) with a total of 37 fusion levels were included. 15 patients had degenerative spondylosis and 5 patients had degenerative scoliosis. The cages covered >60% of the vertebral body diameters. Lumbar lordosis angle and segmental disc angle increased from 45.2 ± 14.5 and 7.3 ± 3.6 to 52.7 ± 9.1 and 10.5 ± 3.5 (p =  0.029 and 0.0002) postoperatively for each parameter respectively without loss of correction at one year follow up. One case of deep postoperative infection occurred (5%). No cage subsidence occurred. No non-union or screw loosening occurred.

Conclusions: The modular TLIF cage was safe with regard to subsidence and union-rate. It restored and maintained lumbar lordosis angle, segmental disc angle and disc height, which can be attributed to the large footprint of this modular cage.

Clinical and radiological effect of medialized cortical bone trajectory for lumbar pedicle screw fixation in patients with degenerative lumbar spondylolisthesis: study protocol for a randomized controlled trial (mPACT)

Background

Spinal fusion with pedicle screw fixation represents the gold standard for lumbar degenerative disc disease with instability. Although it is an established technique, it is nevertheless an invasive intervention with high complication rates. Therefore, minimally invasive approaches have been developed, the medialized bilateral screw pedicel fixation (mPACT) being one of them. The study objective is to evaluate prospectively the efficacy and safety of the mPACT technique compared with the traditional trajectory for degenerative lumbar spondylolisthesis.

Methods/design

This is a single-center, randomized, controlled, parallel group, superiority trial. A total of 154 adult patients are allocated in a ratio of 1:1. Sample size and power calculation were performed to detect the minimal clinically important difference of 10%, with an expected standard deviation of 20% in the primary outcome parameter, the Oswestry Disability Index, with power of 80%, based on an assumed maximal dropout rate of 20%. Secondary outcome parameters include the EuroQoL 5-Dimension questionnaire, the Beck Depression Inventory, the painDETECT questionnaire and the “timed up and go” test. Furthermore, radiological and health economic outcomes will be evaluated. Follow up is performed until 5 years after surgery. Major inclusion criteria are lumbar degenerative spondylolisthesis with Meyerding grade I or II, which qualifies for decompression and fusion by medialised posterior screw placement with cortical trajectory (mPACT) or by a traditional trajectory for lumbar pedicle screw placement.

Discussion

This trial will contribute to the understanding of the short-term and long-term clinical and radiological postoperative course in patients with lumbar degenerative disc disease, in which the mPACT technique is used.

Trial registration

ISRCTN registry, ISRCTN99263604. Registered on 3 November 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2504-z) contains supplementary material, which is available to authorized users.

LEARNING CURVE IN SINGLE-LEVEL MINIMALLY INVASIVE TLIF: EXPERIENCE OF A NEUROSURGEON

ABSTRACT Objective: To describe the learning curve that shows the progress of a single neurosurgeon when performing single-level MI-TLIF. Methods: We included 99 consecutive patients who underwent single-level MI-TLIF by the same neurosurgeon (JASS). Patient’s demographic characteristics were analyzed. In addition, surgical time, intraoperative blood loss and hospital stay were evaluated. The learning curves were calculated with a piecewise regression model. Results: The mean age was 54.6 years. The learning curves showed an inverse relationship between the surgical experience and the variable analyzed, reaching an inflection point for surgical time in case 43 and for blood loss in case 48. The mean surgical time was 203.3 minutes (interquartile range [IQR] 150-240 minutes), intraoperative bleeding was 97.4ml (IQR 40-100ml) and hospital stay of four days (IQR 3-5 days). Conclusions: MI-TLIF is a very frequent surgical procedure due to its effectiveness and safety, which has shown similar results to open procedure. According to this study, the required learning curve is slightly higher than for open procedures, and is reached after about 45 cases.

Interbody Fusion Techniques in the Surgical Management of Degenerative Lumbar Spondylolisthesis

PURPOSE OF REVIEW

The various lumbar interbody fusion (IBF) techniques and the evidence for their use in the treatment of degenerative lumbar spondylolisthesis (DLS) are described in this review.

RECENT FINDINGS

The existing evidence is mixed regarding the indications for and utility of IBF in DLS, but its use in the setting of pre-operative instability is most strongly supported. Anterior (ALIF), lateral (LLIF), posterior (PLIF), transforaminal (TLIF), and axial (AxiaLIF) lumbar IBF approaches have been described. While the current data are limited, TLIF may be a better option than PLIF in DLS due the increased operative morbidity and peri-operative complications observed with the latter. LLIF also appears superior to PLIF in light of improved radiologic outcomes, fewer intra-operative complications, and potentially greater improvements in disability. The data comparing LLIF to TLIF are less conclusive. No studies specifically comparing ALIF or AxiaLIF to other IBF techniques could be identified. Instability may be the strongest indication for IBF in DLS. When IBF is employed, the authors' preferred technique is TLIF with posterior segmental spinal instrumentation. Further research is needed.

Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion Provides Sustained Improvements in Clinical and Radiological Outcomes up to 5 Years Postoperatively in Patients with Neurogenic Symptoms Secondary to Spondylolisthesis

STUDY DESIGN

Retrospective review of prospective registry data.

PURPOSE

To determine 5-year clinical and radiological outcomes of single-level instrumented minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in patients with neurogenic symptoms secondary to spondylolisthesis.

OVERVIEW OF LITERATURE

MIS-TLIF and open approaches have been shown to yield comparable outcomes. This is the first study to assess MIS-TLIF outcomes using the minimal clinically important difference (MCID) criterion.

METHODS

The outcomes of 56 patients treated by a single surgeon, including the Oswestry disability index (ODI), neurogenic symptom score, short-form 36 questionnaire (SF-36), and visual analog scale (VAS) scores for back pain (BP), and leg pain (LP), were collected prospectively for up to 5 years postoperatively. Radiological outcomes included adjacent segment degeneration, fusion, cage subsidence, and screw loosening rates.

RESULTS

Our patients were predominantly female (71.4%) and had a mean age of 53.7±11.3 years and mean body mass index of 25.7±3.7 kg/m². The mean operative time, blood loss, time to ambulation, and hospitalization were 167±49 minutes, 126±107 mL, 1.2±0.4 days, and 2.8±1.1 days, respectively. The mean fluoroscopic time was 58.4±33 seconds, and the mean postoperative intravenous morphine dose was 8±2 mg. Regarding outcomes, postoperative scores improved relative to preoperative scores, and this was sustained across various time points for up to 5 years (p<0.001). Improvements in ODI, SF-36, VAS-BP, and VAS-LP all met the MCID criterion. Notably, 5.4% of our patients developed clinically significant adjacent segment disease during follow-up, and 7 minor complications were reported.

CONCLUSIONS

Single-level instrumented MIS-TLIF is suitable for patients with neurogenic symptoms secondary to lumbar spondylolisthesis and is associated with an acceptable complication rate. Both clinical and radiological outcomes were sustained up to 5 years postoperatively, with many patients achieving an MCID.

The Outcomes of Minimally Invasive versus Open Posterior Approach Spinal Fusion in Treatment of Lumbar Spondylolisthesis: The Current Evidence from Prospective Comparative Studies

Purpose. To investigate the evidence of minimally invasive (MI) versus open (OP) posterior lumbar fusion in treatment of lumbar spondylolisthesis from current prospective literatures. Methods. The electronic literature database of Pubmed, Embase, and Cochrane library was searched at April 2016. The data of operative time, estimated blood loss and length of hospital stay, visual analog scale (VAS) of both lower back pain and leg pain, Oswestry disability index (ODI), SF-36 PCS (physical component scores) and SF-36 MCS (mental component scores), complications, fusion rate, and secondary surgery were extracted and analyzed by STATA 12.0 software. Results. Five nonrandom prospective comparative studies were included in this meta-analysis. The meta-analysis showed that the MI group had a significantly longer operative time than OP group, less blood loss, and shorter hospital stay. No significant difference was found in back pain, leg pain, ODI, SF-36 PCS, SF-36 MCS, complications, fusion rate, and secondary surgery between MI and OP groups. Conclusion. The prospective evidence suggested that MI posterior fusion for spondylolisthesis had less EBL and hospital stay than OP fusion; however it took more operative time. Both MI and OP fusion had similar results in pain and functional outcomes, complication, fusion rate, and secondary surgery.

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 posterior versus transforaminal lumbar interbody fusion using finite element analysis. Influence on adjacent segmental degeneration

OBJECTIVES

To compare the influence of posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) on adjacent segment degeneration (ASD).

METHODS

The study was carried out in the Traumatology and Orthopedics Laboratory, Department of Traditional Chinese Medicine, Medical School, Jinan University, Guangzhou, China, between December 2013 and November 2014. A normal, healthy finite element model of L3-5 was developed, a PLIF and a TLIF model were modified from the normal model, and interbody fusions were performed in the L4-5 segment. An 800 N compressive loading plus 10 Nm moments simulating flexion, extension, lateral bending, and axial rotation were imposed on the L3 superior endplate. Intradiscal pressure and intersegmental rotation in L3-4 were investigated.

RESULTS

The values of intradiscal pressure and intersegmental rotation in the PLIF or TLIF model were higher than those in the normal, healthy model, but the values in the TLIF model were relatively lower than those in the PLIF model in all directions. 

CONCLUSION

Posterior lumbar interbody fusion has more adverse influence on the superior adjacent segment than TLIF.

Dural Traction a Possible Cause of Hemodynamic Changes During Single-Level Transforaminal Lumbar Interbody Fusion

BACKGROUND

Lumbar spinal surgery may be associated with electrophysiologic and hemodynamic abnormalities during the procedure.

CASE DESCRIPTION

A 58-year-old man with grade II L4-5 spondylolisthesis and degenerative changes underwent single-level transforaminal lumbar interbody fusion. During decompression of the L4 foramina, distraction of the disc space, and placement of the interbody cage and pedicle screws, episodes of extreme bradycardia with up to 5 seconds of asystole were detected on electrocardiogram and invasive hemodynamic monitoring. The events correlated with and possibly could have been a result of traction on the dura mater.

CONCLUSIONS

Anesthesia providers should be aware of electrophysiologic and hemodynamic abnormalities during lumbar spinal surgery and the need to respond appropriately with sympathomimetic or vagolytic interventions.

Transforaminal lumbar interbody fusion versus posterolateral fusion in degenerative lumbar spondylosis: A meta-analysis

OBJECTIVE

The aim of the study was to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) versus posterolateral fusion (PLF) in degenerative lumbar spondylosis.

METHODS

A systematic literature review was performed to obtain randomized controlled trials (RCTs) and observational studies (OSs) of TLIF and PLF for degenerative lumbar spondylosis. Trials performed before November 2015 were retrieved from the Medline, EMBASE, Cochrane library, and Chinese databases. Data extraction and quality evaluation of the trials were performed independently by 2 investigators. A meta-analysis was performed using STATA version 12.0.

RESULTS

Two RCTs and 5 OSs of 630 patients were included. Of these subjects, 325 were in the TLIF and 305 were in the PLF group. Results showed that TLIF did not increase the fusion rate based on RCTs (relative risk [RR] = 1.06; 95% confidence interval [CI]: 0.95-1.18; P = 0.321), but increased it based on OSs (RR = 1.14; 95% CI: 1.07-1.23; P = 0.000) and overall (RR = 1.11; 95% CI: 1.05-1.18; P = 0.001) as compared with PLF. TLIF was able to improve the clinical outcomes based on 1 RCT (RR = 1.33; 95% CI: 1.11-1.59, P = 0.002) and overall (RR = 1.19; 95% CI: 1.07-1.33; P = 0.001), but not based on OSs (RR = 1.11; 95% CI: 0.97-1.27; P = 0.129) as compared with PLF. There were no differences between TLIF and PLF in terms of visual analogue scale, Oswestry Disability Index, reoperation, complications, duration of surgical procedure, blood loss, and hospitalization.

CONCLUSIONS

In conclusion, evidence is not sufficient to support that TLIF provides higher fusion rate than PLF, and this poor evidence indicates that TLIF might improve only clinical outcomes. Higher quality, multicenter RCTs are needed to better define the role of TLIF and PLF.

Operative Management of Lumbar Degenerative Disc Disease

Lumbar degenerative disc disease is extremely common. Current evidence supports surgery in carefully selected patients who have failed non-operative treatment and do not exhibit any substantial psychosocial overlay. Fusion surgery employing the correct grafting and stabilization techniques has long-term results demonstrating successful clinical outcomes. However, the best approach for fusion remains debatable. There is some evidence supporting the more complex, technically demanding and higher risk interbody fusion techniques for the younger, active patients or patients with a higher risk of non-union. Lumbar disc arthroplasty and hybrid techniques are still relatively novel procedures despite promising short-term and mid-term outcomes. Long-term studies demonstrating superiority over fusion are required before these techniques may be recommended to replace fusion as the gold standard. Novel stem cell approaches combined with tissue engineering therapies continue to be developed in expectation of improving clinical outcomes. Results with appropriate follow-up are not yet available to indicate if such techniques are safe, cost-effective and reliable in the long-term.