Lumbar Interbody Fusion Approach Research Articles

Trans-Pars Interarticularis Approach for Lumbar Interbody Fusion: An Efficient, Straightforward, and Minimally Invasive Surgery for Lumbar Spondylolisthesis and Stenosis.

Lumbar interbody fusion is a commonly applied surgical treatment for spondylolisthesis. For this procedure, various minimally invasive (MIS) approaches have been developed, including posterior lumbar interbody fusion, transforaminal lumbar interbody fusion (TLIF), oblique lumbar interbody fusion, and anterior lumbar interbody fusion. In this study, we characterized the features of an MIS trans-pars interarticularis lumbar interbody fusion (TPLIF) and compared its surgical outcomes with those of MIS-TLIF. This study included 89 and 44 patients who had undergone MIS-TPLIF and MIS-TLIF, respectively, between September 2016 and December 2022. The following clinical outcomes were analyzed: operative time, blood loss, and hospitalization duration. The average operative time, blood loss, and hospitalization duration for the MIS-TPLIF and MIS-TLIF groups were, respectively, 98.28 and 191.15 minutes, 41.97 and 101.85 mL, and 5.8 and 6.9 days. The MIS-TPLIF approach for lumbar spondylolisthesis or other degenerative diseases involves the use of the commonly available and cost-effective instrument Taylor retractor, thus enabling posterior lumbar interbody fusion to be performed with minimal invasion. This approach also confers the benefits of a short learning curve and an intuitive approach. Our results suggest that although MIS-TPLIF is noninferior to MIS-TLIF, it is easier to learn and perform than MIS-TLIF.

Transforaminal Versus Lateral Interbody Fusions for Treatment of Adjacent Segment Disease in the Lumbar Spine.

Retrospective comparative study. This study compared outcomes for patients managed with a lateral approach to interbody fusion [lateral (LLIF) or oblique (OLIF)] versus a posterior (PLIF) or transforaminal interbody fusion (TLIF) for treatment of adjacent segment disease (ASD) above or below a prior lumbar fusion construct. No study has compared outcomes of lateral approaches to more traditional posterior approaches for the treatment of ASD. Retrospective review was performed of patients who underwent single-level lateral or posterior approaches for lumbar interbody fusion for symptomatic ASD between January 2010 and December 2021. Exclusion criteria included skeletal immaturity (age below 18y old) and surgery indication for malignancy or infection. Patient demographics, medical comorbidities, operative details, postoperative complications, and revision surgery profiles were collected for all patients. Standard descriptive statistics were used to summarize data. Comparative statistical analyses were performed using Statistical Package for the Social Sciences (Version 28.0.1.0; Chicago, IL). A total of 152 patients (65±10y) were included in the study with a mean duration of follow-up of 1.6±1.4 years. The cohort included 123 PLIF/TLIF (81%), 18 LLIF (12%), 11 OLIF (7%). TLIF/PLIF experienced greater mean operative time (210±62min vs. 184±80 OLIF/105±64 LLIF, P<0.001) and estimated blood loss (414±254mL vs. 49±29 OLIF/36±33 LLIF, P<0.001). No significant difference in rate of postoperative complications. Postoperative radicular pain was significantly greater in OLIF (7, 64%) and LLIF (7, 39%) compared with PLIF/TLIF (16, 13%), P<0.001. No statistically significant difference in health care utilization was noted between the groups. Lateral fusions to treat ASD demonstrated no significantly different risk of complication compared with posterior approaches. Our study demonstrated significantly increased operative time and estimated blood loss for the posterior approach and an increased risk of radicular pain from manipulation/retraction of psoas following lateral approaches. Level III.

Tomographic Assessment of Fusion Rate, Implant-Endplate Contact Area, Subsidence, and Alignment With Lumbar Personalized Interbody Implants at 1-Year Follow-Up.

Incongruity between irregularly shaped vertebral endplates and the uniform surfaces of stock interbody fusion cages has been identified as contributing to cage subsidence, pseudarthrosis, and unpredictable alignment. Advances in manufacturing techniques have driven the development of personalized interbody cages (PICs) that can match individual endplate morphology and provide the exact shape and size needed to fill the disc space and achieve the planned correction. This study used computed tomography (CT) imaging to evaluate the implant-endplate contact area, fusion, subsidence, and achievement of planned alignment correction in patients receiving PIC devices. This retrospective study included patients treated for adult spinal deformity at a single site and implanted with PIC devices at L4 to L5 or L5 to S1 for segmental stabilization and alignment correction, who received 1-year postoperative CT images as part of their standard of care. An evaluation using 3-dimensional thin-section scans was conducted. Implant-endplate contact and signs of fusion were assessed in each CT slice across both endplates. The degree of subsidence as well as measures of segmental and global lumbar alignment were also assessed. Fifteen patients were included in the study, with a mean age of 68.2 years. Follow-up ranged between 9 and 14 months. Twenty-six total lumbar levels were implanted; 20 with PIC devices via the anterior lumbar interbody fusion approach, 2 with stock cages via the anterior lumbar interbody fusion approach, and 4 with PIC devices via the transforaminal lumbar interbody fusion approach. CT analysis of PIC-implanted levels found an overall implant-endplate contact area ratio of 93.9%, a subsidence rate of 4.5%, a fusion rate of 100%, and satisfactory segmental and global lumbar correction compared with the preoperative plan. PIC implants can provide nearly complete contact with endplate surfaces regardless of the individual endplate morphology. Subsidence, fusion, and alignment assessments in this tomographic study illustrated results consistent with the benefits of a personalized interbody implant.

A Cadaveric Comparison of Discectomy Performance During Transforaminal Lumbar Interbody Fusion Approach Using an Endoscopic Technique versus a Minimally Invasive Tubular Approach.

Cadaveric study. Compare discectomy performance between transforaminal lumbar interbody fusion (TLIF) done via an endoscopic versus a tubular technique. Performance of an adequate discectomy is essential to lumbar fusion when performing a TLIF. Previous cadaveric studies comparing open and minimally invasive techniques have reported 36.6%-80% discectomy. There is controversy whether an endoscopic TLIF (E-TLIF) can allow for an adequate discectomy. An E-TLIF was performed on 14 discs (T12-L5) and a minimally invasive tubular TLIF (T-TLIF) was performed on 15 discs (T12-L4, L5-S1). Fellowship trained surgeons performed the TLIFs. Each disc was transected after discectomy and a digital image was analyzed using an imaging processing software to determine the percent of discectomy. Each quadrant of the discectomy was compared. Quadrant one was defined as the left posterior-ipsilateral quadrant of the disc, with each quadrant numbered 2-4 clockwise around the disc. The time to perform the discectomy was compared. Pedicle screws were placed contralaterally to the TLIF and the change in interpedicular distance was compared between techniques after expandable cage implantation as a marker for indirect decompression. A student's t-test was used to determine statistical significance. There was no difference in discectomy performance between techniques (48.86%+/-6.98% T-TLIF vs. 50.26%+/-7.38% E-TLIF, P=0.61). There was no statistical difference between T-TLIF vs E-TLIF at quadrants 1, 3 and 4. There was a difference in discectomy performance at quadrant 2 (39.02%+/-10.18% T-TLIF vs 50.13%+/-14.00% E-TLIF, P=0.02). There was no statistical difference between interpedicular distance created (2.20mm+/-1.97mm T-TLIF vs 1.36mm+/-1.82mm E-TLIF, P=0.24). E-TLIF took less time than MIS-TLIF (20.00min+/-7.12min vs 15.22min+/-4.42min, P=0.048). Our cadaveric study demonstrates that an adequately performed E-TLIF discectomy may be comparable to a T-TLIF discectomy. Further research is required to maximize the efficiency and instrumentation of this technique.

A retrospective analysis of perioperative complications of lateral approach lumbar interbody fusion in patients with prior abdominal surgery or a history of colonic inflammatory disease

BACKGROUND CONTEXTLateral approaches for lumbar interbody fusion (LIF) allow for access to the lumbar spine and disc space by passing through a retroperitoneal corridor either pre- or trans-psoas. A contraindication for this approach is the presence of retroperitoneal scarring that may occur from prior surgical intervention in the retroperitoneal space or from inflammatory conditions with fibrotic changes and pose challenges for the mobilization and visualization needed in this approach. However, there is a paucity of evidence on the prevalence of surgical complications following lateral fusion surgery in patients with a history of abdominal surgery. PURPOSEThe primary aim of this study is to describe the association between surgical complications following lateral interbody fusion surgery and prior abdominal surgical. STUDY DESIGNRetrospective study. PATIENT SAMPLEPatients over the age of 18 who underwent lateral lumbar interbody fusion at a large, tertiary care center between 2011 and 2019 were included in the study. OUTCOME MEASURESThe primary outcome included medical, surgical, and thigh-related complications either in the intraoperative or 90-day postoperative periods. Additional outcome metrics included readmission rates, length of stay, and operative duration. METHODSThe electronic health records of 250 patients were reviewed for demographic information, surgical data, complications, and readmission following surgery. The association of patient and surgical factors to complication rate was analyzed using multivariable logistic regression. Statistical analysis was performed using R statistical software (R, Vienna, Austria). RESULTSOf 250 lateral interbody fusion patients, 62.8% had a prior abdominal surgery and 13.8% had a history of colonic disease. The most common perioperative complication was transient thigh or groin pain/sensory changes (n=62, 24.8%). A multivariable logistic regression considering prior abdominal surgery, age, BMI, history of colonic disease, multilevel surgery, and the approach relative to psoas found no significant association between surgical complication rates and colonic disease (OR 0.40, 95% CI 0.02–2.22) or a history of prior abdominal surgeries (OR 0.56, 95% CI 0.20–1.55). Further, the invasiveness of prior abdominal surgeries showed no association with overall spine complication rate, lateral-specific complications, or readmission rates (p>.05). CONCLUSIONThough retroperitoneal scarring is an important consideration for lateral approaches to the lumbar spine, this study found no association between lateral lumbar approach complication rates and prior abdominal surgery. Further study is needed to determine the impact of inflammatory colonic disease on lateral approach spine surgery.

Clinical outcomes, MRI evaluation and predictive factors of indirect decompression with lateral transpsoas approach for lumbar interbody fusion: a multicenter experience.

Evaluating the effects of indirect decompression obtained through lateral lumbar interbody fusion (LLIF) by clinical improvements and radiological parameters on MRI scans. Identifying predictors of better decompression and clinical outcome. From 2016 to 2019, patients who underwent single- or double-level indirect decompression LLIF were consecutively reviewed. Radiological signs of indirect decompression were evaluated in preoperative and follow-up MRI studies and were subsequently correlated to clinical data, expressed as axial/radicular pain (VAS back/leg), index of disability (Oswestry Disability Index) and clinical severity of lumbar stenosis (Swiss Spinal Stenosis Questionnaire). 72 patients were enrolled. The mean follow-up was 24 months. Differences in vertebral canal area (p < 0.001), height of the foramina (p < 0.001), thickness of the yellow ligament (p = 0.001) and anterior height of the interbody space (p = 0.02) were observed. Older age (p = 0.042), presence of spondylolisthesis (p = 0.042), presence of intra-articular facet effusion (p = 0.003) and posterior height of the implanted cage (p = 0.020) positively affected the increase of the canal area. Change in root canal area (p < 0.001), height of the implanted cage (p = 0.020) and younger age (p = 0.035) were predictive factors of root pain relief, while increased vertebral canal area (p = 0.020) and height of the interbody fusion cage (p = 0.023) positively affected the severity of clinical stenosis. LLIF indirect decompression showed both clinical and radiological improvements. Presence and degree of spondylolisthesis, presence of intra-articular facet effusion, age of the patient and height of the cage were predictive factors of major clinical improvements.

Incidence of Surgical Site Infection Following Lateral Lumbar Interbody Fusion Compared With Posterior/Transforaminal Lumbar Interbody Fusion: A Propensity Score-Weighted Study.

Retrospective cohort study. The objective of this study was to compare the incidence of surgical site infection (SSI) after lateral lumbar interbody fusion (LLIF) and posterior/transforaminal lumbar interbody fusion ( P /TLIF). Previous studies have shown that LLIF can improve neurological symptoms to a comparable degree to P /TLIF. However, data on the risk of SSI after LLIF is lacking compared with P /TLIF. The study was conducted under a retrospective cohort design in patients undergoing LLIF or P /TLIF for lumbar degenerative diseases between 2013 and 2020 using a hospital administrative database. We used propensity score overlap weighting to adjust for confounding factors including age, sex, body mass index, comorbidities, number of fusion levels, hospital size, and surgery year. We estimated weighted odds ratios (ORs) and 95% CIs for SSI within 30 days postoperatively. We compared the risk of SSI between 2874 patients who underwent LLIF and 24,245 patients who received P/TLIF Patients who had received LLIF were at significantly less risk of experiencing an SSI compared with those receiving P/TLIF (0.7% vs. 1.2%; weighted OR: 0.57; 95% CI: 0.36 -0.92; P=0.02). As a secondary outcome, patients who had received LLIF had less risk of transfusion (7.8% vs. 11.8%; weighted OR: 0.63; 95% CI:0.54 -0.73; P <0.001). In this large retrospective cohort study of adults undergoing lumbar interbody fusion, LLIF was associated with a significantly lower risk of SSI than P /TLIF. The small, but significantly, decreased risk of SSI associated with LLIF may inform decisions regarding the technical approach for lumbar interbody fusion.

Anterior lumbar spinal fusion surgery associated with lower risk of stroke, pneumonia, and infection compared to posterior lumbar spinal fusion surgery

BackgroundPrior studies, comparing anterior and posterior approaches to lumbar fusion surgery, found similar fusion rates and clinical outcomes, but are limited by sample size. Further evaluation of the postoperative complications of each approach is necessary. MethodsThe MSpine database by PearlDiver was queried using ICD-9, ICD-10, and CPT codes to identify patients who had undergone single-level anterior or posterior lumbar interbody fusion surgery. Readmission rates, ileus, lower extremity DVT, infection, pneumonia, and stroke were used to compare post-operative complications of an anterior vs. posterior approach. Results112,023 patients were included in this study, with 38,529 (34.4%) in the anterior group (ALIF/LLIF) and 73,494 (65.6%) in the posterior group (PLIF/TLIF). At both 30 and 90-days postoperative, patients undergoing an anterior approach to lumbar interbody fusion had a higher odds ratio of lower extremity DVT (30-day OR: 1.19, 90-day OR: 1.16; P<0.05) and ileus complication (30-day OR: 1.87, P= <.05; 90-day OR: 1.81, P<.05). At both 30 and 90-days postoperative, patients undergoing a posterior approach had a higher odds ratio of stroke (30-day: OR: 0.79, 90-day OR: 0.87; P<0.05), transfusion (30-day OR: 0.66, 90-day OR: 0.69; P<.05), infection (30-day OR: 0.88, 90-day OR: 0.91; P <.05), and pneumonia (30-day OR: 0.85, 90-day OR: 0.90; P<.05). There was no statistically significant difference in myocardial infarction or pulmonary embolism between both approaches at 30 and 90-days postoperative. ConclusionsAnterior and posterior approaches for lumbar interbody fusion were associated with differences in postoperative complications at 30 and 90-days. The complication profiles associated with each approach can inform surgeon treatment decisions based on patient profiles.

Independent Predictors of Revision Lumbar Fusion Outcomes and the Impact of Spine Surgeon Variability: Does It Matter Whether the Primary Surgeon Revises?

There is a paucity of information regarding treatment strategies and variables affecting outcomes of revision lumbar fusions. To evaluate the influence of primary vs different surgeon on functional outcomes of revisions. All elective lumbar fusion revisions, March 2018 to August 2019, were retrospectively categorized as performed by the same or different surgeon who performed the primary surgery. Oswestry Disability Index (ODI) and clinical variables were collected. Multiple logistic regression identified multivariable-adjusted odds ratio (OR) of independent variables analyzed. Of the 130 cases, 117 (90%) had complete data. There was a slight difference in age in the same (median: 59; interquartile range [IQR], 54-66) and different surgeon (median: 67; IQR, 56-72) groups (P=.02); all other demographic variables were not significantly different (P >.05). Revision surgery with a different surgeon had an ODI improvement (median: 8; IQR, 2-14) greater than revisions performed by the same surgeon (median: 1.5; IQR, -3 to 10) (P <.01). Revisions who achieved minimum clinically important difference (MCID) performed by different surgeon (59.7%) were also significantly greater than the ones performed by the same surgeon (40%) (P=.042). Multivariate analysis demonstrated that a different surgeon revising (OR, 2.37; [CI]: 1.007-5.575, P=.04) was an independent predictor of MCID achievement, each additional 2 years beyond the last surgery conferred a 2.38 ([CI]: 1.36-4.14, P <.01) times greater odds of MCID achievement, and the anterior lumbar interbody fusion approach decreased the chance of achieving MCID (OR, 0.19; [CI]: 0.04-0.861, P=.03). All revision lumbar spinal fusion approaches may not achieve the same outcomes. This analysis suggests that revision surgeries may have better outcomes when performed by a different surgeon.

1044 Impact of Obesity on Complications from Anterior Lumbar Interbody Fusion

Abstract Aim Anterior Lumbar Interbody Fusion is a procedure growing in popularity for conditions including degenerative disc disease, and discogenic back pain. Obesity is a significant risk factor in the development of back pain, with patients with raised BMIs at increased of complications using the posterior approach. This review aims to evaluate the risk profile of this patient cohort using the anterior approach for lumbar interbody fusion. Method A systematic review of the search databases Pubmed; google scholar; and OVID Medline was carried out between September 2020-November 2020. Studies evaluating the risks associated with obesity during Anterior Lumbar Interbody Fusion (ALIF) were identified and included for review according to PRISMA guidelines. Studies eligible for inclusion were agreed by two independent reviewers. Meta-analysis was used to compare intra- and postoperative complications in patients with increased BMI during ALIF. Results Search terms yielded 435 articles for evaluation. 13 studies were included in this review after applying inclusion and exclusion criteria. Meta-analysis of studies demonstrated a significantly increased risk profile for overall complications in the obese patient cohort (CI = 0.04-0.16, p = 0.002) with significant heterogeneity (I2=86%). Patients with increased BMI were not significantly more likely to develop Vascular complications (CI= -.03-0.02, p = 0.62). Simple pooling demonstrated significant association between increased BMI and blood loss. Conclusions Obesity was demonstrated to have an impact on overall complication rates in Anterior Lumbar Interbody Fusion procedures, with postoperative complications including wound infections and lower fusion rates more common in patients in increased BMIs.

Lateral access techniques for degenerative conditions of the spine

Operative approaches for degenerative conditions of the spine include traditional posterior approaches and a newer generation of lateral approaches. These operative corridors have their roots in anterior lumbar fusion and modifications have evolved to include lateral and oblique lumbar interbody fusion. The principal advantages of lateral approaches are that they are minimally invasive, less disruptive, and provide greater access to the disc space, thus allowing for larger cage placement and theoretically greater indirect foraminal decompression with lower rates of subsidence. We describe the anterior, lateral, and oblique lumbar interbody fusion approaches, with particular emphasis on surgical techniques and complications.

P11. Does the choice of spinal interbody fusion approach significantly affect adjacent segment mobility?

<h3>BACKGROUND CONTEXT</h3> 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. <h3>PURPOSE</h3> 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). <h3>STUDY DESIGN/SETTING</h3> 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). <h3>PATIENT SAMPLE</h3> Human cadaveric lumbar spine. <h3>OUTCOME MEASURES</h3> Adjacent segment range of motion. <h3>METHODS</h3> Normalized ROM data at the levels adjacent to L3–L4 PSR fixation with 3 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. <h3>RESULTS</h3> 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. <h3>CONCLUSIONS</h3> The choice of lumbar interbody fusion approach influences adjacent segment motion in a cadaveric model. LLIF had the least adjacent segment motion. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Peri-Surgical Inflammatory Profile Associated with Mini-Invasive or Standard Open Lumbar Interbody Fusion Approaches.

Background: Different surgical approaches are available for lumbar interbody fusion (LIF) to treat disc degeneration. However, a quantification of their invasiveness is lacking, and the definition of minimally invasive surgery (MIS) has not been biochemically detailed. We aimed at characterizing the inflammatory, hematological, and clinical peri-surgical responses to different LIF techniques. Methods: 68 healthy subjects affected by single-level discopathy (L3 to S1) were addressed to MIS, anterior (ALIF, n = 21) or lateral (LLIF, n = 23), and conventional approaches, transforaminal (TLIF, n = 24), based on the preoperative clinical assessment. Venous blood samples were taken 24 h before the surgery and 24 and 72 h after surgery to assess a wide panel of inflammatory and hematological markers. Results: martial (serum iron and transferrin) and pro-angiogenic profiles (MMP-2, TWEAK) were improved in ALIF and LLIF compared to TLIF, while the acute phase response (C-reactive protein, sCD163) was enhanced in LLIF. Conclusions: MIS procedures (ALIF and LLIF) associated with a reduced incidence of post-operative anemic status, faster recovery, and enhanced pro-angiogenic stimuli compared with TLIF. LLIF associated with an earlier activation of innate immune mechanisms than ALIF and TLIF. The trend of the inflammation markers confirms that the theoretically defined mini-invasive procedures behave as such.

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

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). 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). 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. 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. 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. 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.

A comparison of the bilateral decompression via unilateral approach versus conventional approach transforaminal lumbar interbody fusion for the treatment of lumbar degenerative disc disease in the elderly

BackgroundBilateral decompression via unilateral approach (BDUA) is an effective surgical approach for treating lumbar degenerative diseases. However, no studies of prognosis, especially the recovery of the soft tissue, have reported using BDUA in an elderly population. The aims of these research were to investigate the early efficacy of the bilateral decompression via unilateral approach versus conventional approach transforaminal lumbar interbody fusion (TLIF) for the treatment of lumbar degenerative disc disease in the patients over 65 years of age, especially in the perioperative factors and the recovery of the soft tissue.MethodsThe clinical data from 61 aging patients with lumbar degenerative disease who received surgical treatment were retrospectively analyzed. 31 cases who received the lumbar interbody fusion surgery with bilateral decompression via unilateral approach (BDUA) were compared with 30 cases who received conventional approach transforaminal lumbar interbody fusion. The radiographic parameters were measured using X-ray including lumbar lordosis angle and fusion rate. Japanese Orthopedic Association (JOA), Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores were used to evaluate the clinical outcomes at different time points. Fatty degeneration ratio and area of muscle/vertebral body were used to detect recovery of soft tissue.ResultsThe BDUA approach group was found to have significantly less intraoperative blood loss(p < 0.05) and postoperative drainage(p < 0.05) compared to conventional approach transforaminal lumbar interbody fusion group. Symptoms of spinal canal stenosis and nerve compression were significantly relieved postoperatively, as compared with the preoperative state. However, the opposite side had a lower rate of fatty degeneration (9.42 ± 3.17%) comparing to decompression side (11.68 ± 3.08%) (P < 0.05) six months after surgery in the BDUA group. While there were no significant differences (P > 0.05) in two sides of conventional transforaminal lumbar interbody fusion approach group six months after surgery.ConclusionsBilateral decompression via unilateral approach (BDUA) is able to reduce the intraoperative and postoperative body fluid loss in the elderly. The opposite side of decompression in BDUA shows less fatty degeneration in 6 months, which indicates better recovery of the soft tissue of the aging patients.

Lumbar interbody fusion: recent advances in surgical techniques and bone healing strategies.

Lumbar interbody fusion (LIF) is a treatment option for low back pain secondary to lumbar instability and/or deformity. This review highlights recent studies of surgical techniques and bone healing strategies for LIF. Relevant articles were identified by searching the PubMed database from January 1948 to April 2020, with a focus on the last 5years, using the following keywords: LIF approach, LIF cage, stem cells for LIF, biomaterials for LIF, and osteobiologics for LIF. LIF procedures were traditionally performed through either a posterior approach (PLIF), or an anterior approach. Later, the transforaminal LIF approach gained popularity over the PLIF as it entailed less nerve retraction. To minimize paraspinal muscle dissections, alternative approaches including lateral LIF, oblique LIF, and minimally invasive approaches have been developed and utilized. These modifications have improved the surgical outcomes of LIF. However, the most recent rates of non-union after LIF procedures still ranged from 7 to 20% with an even higher incidence in patients with osteoporosis. This review summarizes the advantages and disadvantages of each surgical approach and current efforts to enhance LIF by improving fusion cage material properties and developing novel osteobiologic products that contain nanomaterials for controlled release of effective osteogenic proteins and mesenchymal stem cells. There have been significant advances in surgical technologies for LIF over the past decades. Post-operative non-union remains a major challenge, which could be addressed by development of more effective surgical techniques, fusion cages, and bone healing products through joint efforts from spine surgeons, bone biologists, and material engineers.

45. A prospective, in-depth analysis of perioperative anterior thigh symptoms associated with a direct lateral access approach for lumbar interbody fusion

BACKGROUND CONTEXT Anterior thigh symptoms post-transpsoas lateral approach for lumbar interbody arthrodesis are well documented. Symptoms may be transient ( PURPOSE The aim of this analysis was to prospectively characterize adverse perioperative neurological changes associated with a direct lateral transpsoas retroperitoneal closed tubular retractor system. Further, provider-reported changes were compared vs subject-reported changes. STUDY DESIGN/SETTING This investigation is a prospective, multicenter, single-arm, IRB approved post-market study. PATIENT SAMPLE One hundred fifteen subjects (115), 71 females (61.7%), with a mean age of 64.0 and mean BMI of 30.8 presenting with degenerative disc disease at one or two adjacent levels from L2 to L5 were included for analysis. OUTCOME MEASURES Subjects self-reported thigh pain, hip flexion weakness, and knee extension weakness on a 100mm Visual Analog Scale. Clinical assessments including muscle strength, Achilles reflexes, patellar reflexes, and sensory testing were performed at the same time points. Multiple questions specific to lateral access not typically collected in lumbar fusion studies were included in the analysis. METHODS All outcome measures were prospectively collected at the preoperative visit, prior to hospital discharge, and at the two-week, six-week, three-month, six-month, and twelve-month postoperative visits. Data were descriptively analyzed. RESULTS Objective neurological exam showed 17 (14.8%) subjects with access-sided adverse changes from baseline at hospital discharge. These 17 included 5 (4.4%) with changes in strength, 5 (4.4%) with sensation changes, and 11 (9.6%) with reflex changes. Of these, 2 subjects had changes in both strength and reflexes; 2 had changes in both sensation and reflexes. All strength and sensation changes were resolved by 6 weeks. All reflex changes resolved by 3 months. Twenty-two subjects (19.1%) reported increased thigh pain (>20mm) at discharge. All were resolved by 3 months. Forty-four (44) subjects (38.3%) reported increased hip flexion or extension weakness (>20mm) with 29 (65.9%) resolved by 6 weeks, 37 (84.1%) resolved by 3 months, 41/45 (93.2%) resolved by 6 months, and 3 have additional follow-up pending. Of the 17 subjects with objectively identified changes, 7 also reported subjective changes. Only 2 subjects’ (11.8%) reported symptoms (weakness) correlated with objectively reported results (strength). CONCLUSIONS This unique prospective study is the first to our knowledge that captures in-depth subjective and objective thigh symptom data specific to lateral access transpsoas surgery. The perioperative results provide a rare illustration of adverse changes and their almost complete resolution within 3 months. Further research to understand the differences in clinician reported vs subject reported changes is warranted. FDA DEVICE/DRUG STATUS Duo Interbody Fusion System (Approved for this indication)

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.

A Comparison of Complications and Clinical and Radiologic Outcome Between the Mini-open Prepsoas and Mini-open Transpsoas Approaches for Lumbar Interbody Fusion

Systematic review and meta-analysis. To compare complication rates and clinical and radiologic outcome between the mini-open prepsoas and mini-open transpsoas approaches for lateral lumbar interbody fusion. Both approaches are believed to be safe with similar complication rates. Previous studies suggest that the rate of neurological injury might be higher in the transpsoas group, whereas visceral or vascular injury might be more frequent in the prepsoas group. A systematic review of the literature was performed. Data were extracted from original publications up until December 26, 2018. Evidence was extracted from well-designed case-control or cohort studies and sorted in 2 groups, the prepsoas and transpsoas approaches. A meta-analysis was performed using a random-effects model (I statistic >50% for all analyses). A total of 115 studies included data of 13,260 patients, 2450 in the prepsoas group and 10,810 in the transpsoas group. Demographics for prepsoas versus transpsoas group were (N-weighted means): age 61.9 versus 60.9 years; %female sex 53% versus 63%, levels fused 1.4 versus 2.6, blood loss 52.4 versus 122.3 mL, and operating time 125.1 versus 200.7 min. The following statistically significant differences in complication rates between prepsoas and transpsoas approaches were found: transient psoas weakness or thigh/groin numbness 4% versus 26% [95% confidence interval (CI): 11%-17%], motor neural injury 0.4% versus 1.3% (95% CI: 16%-62.3%); no statistically significant differences were found for: major vascular injury 2% versus 1% (95% CI: 1.04%-2.31%), kidney or ureter injury 0.04% versus 0.08% (95% CI: 0.057%-5.2%), injury pleural/peritoneal structures 0.6% versus 0.2% (95% CI: 0.89%-6.58%), cage subsidence 5% versus 4% (95% CI: 0.9%-1.97%), surgical site infection 1% versus 1% (95% CI: 0.57%-1.66%), abdominal wall pseudohernia 1% versus 1% (95% CI: 0.07%-21.22%), sympathetic chain injury 5% versus 0% (95% CI: 0.34%-97.86%), and directly procedure-related death 0.04% versus 0% (95% CI: 0.127%-76.8%). Pooled mean perioperative changes between prepsoas and transpsoas approaches were: segmental sagittal Cobb angle 3.07 versus 1.99 degrees; foraminal height 2 versus 6.96 mm. The prepsoas had fewer complications than the transpsoas approach. Furthermore, the prepsoas approach showed superior restoration of segmental lordosis, whereas foraminal height restoration was superior with the transpsoas approach. This could be explained by the differences in location of the interbody device placement in relation to the center of rotation of the spine between the 2 surgical techniques.

Evolution of Minimally Invasive Lumbar Spine Surgery

Spine surgery has evolved over centuries from first being practiced with Hippocratic boards and ladders to now being able to treat spinal pathologies with minimal tissue invasion. With the advent of new imaging and surgical technologies, spine surgeries can now be performed minimally invasively with smaller incisions, less blood loss, quicker return to daily activities, and increased visualization. Modern minimally invasive procedures include percutaneous pedicle screw fixation techniques and minimally invasive lateral approach for lumbar interbody fusion (i.e., minimally invasive transforaminal lumbar interbody fusion, extreme lateral interbody fusion, oblique lateral interbody fusion) and midline lumbar fusion with cortical bone trajectory screws. Just as evolutions in surgical techniques have helped revolutionize the field of spine surgery, imaging technologies have also contributed significantly. The advent of computer image guidance has allowed spine surgeons to advance their ability to refine surgical techniques, increase the accuracy of spinal hardware placement, and reduce radiation exposure to the operating room staff. As the field of spine surgery looks to the future, many novel technologies are on the horizon, including robotic spine surgery, artificial intelligence, and machine learning to help improve preoperative planning, improve surgical execution, and optimize patient selection to ensure improved postoperative outcomes and patient satisfaction. As more spine surgeons begin incorporating these novel minimally invasive techniques into practice, the field of minimally invasive spine surgery will continue to innovate and evolve over the coming years.