Anterior Lumbar Interbody Fusion Approaches Research Articles

Venous Anomalies Complicating Anterior Lumbar Interbody Fusion Exposures.

The effects of anomalous vasculature impeding optimal exposure to an anterior lumbar interbody fusion approach are limited in literature. We present five individual, unique cases of vascular anomalies in patients undergoing two-stage anterior-posterior lumbar interbody fusion. Cases 1, 2, 4, and 5 have yet to be described in literature in context of anterior lumbar interbody fusions. Case 3 presents anomalous vasculature that has only been described in two other case reports. Case 1 presents the right internal iliac vein originating from the left common iliac vein which was transected for L4-L5 vertebral disc exposure. Case 2 presents the left internal iliac vein originating from the right common iliac vein which required an oblique approach. Case 3 presents a duplicated inferior vena cava that was taken into account but did not interfere with the anterior retroperitoneal approach. Case 4 presents large osteophytes adhering to the left common iliac vein which limited safe dissection and mobilization. Case 5 presents the left internal iliac vein with a high takeoff spanning across the L5-S1 vertebral disc space and requiring transection. This case series highlights the need for preoperative imaging and a working detailed knowledge of anatomy to avoid damaging vasculature that can potentially lead to fatal consequences. The information given in this case series should inform both spine and vascular surgeons on proper preoperative planning. To maximize operative efficiency and safety, spine surgeons and vascular surgeons should collaborate to minimize surgical complications.

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.

Complications Associated With Oblique Lumbar Interbody Fusion at L5-S1: A Systematic Review of the Literature

Abstract INTRODUCTION Oblique lumbar interbody fusion (OLIF) at L5-S1, also known as a lateral decubitus anterior lumbar interbody fusion (ALIF) or anterior-to-psoas (ATP) approach, is a technique that provides a minimally invasive corridor to a key segment in the spine for degenerative conditions and deformity correction. However, the evaluation of complications associated with this level has been difficult as prior reports include other levels that have different anatomic considerations. OBJECTIVE To present a systematic review of previously reported cases of OLIF, lateral ALIF, and an ATP approach at L5-S1 to discuss their associated complications. METHODS Following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a PubMed search was performed up to January 2021 to identify literature describing OLIF, lateral ALIF, and ATP approaches involving the L5-S1 levels. A quality assessment with risk of bias analysis was performed using the methodological index for non-randomized studies (MINORS) assessment tool for each study. Data we then extracted to identify all complications. RESULTS The initial search yielded 532 publications. After screening, there were 18 studies with 553 total patients who underwent OLIF including L5-S1. Analysis of these studies demonstrated a vascular complication rate of 2.5%, bowel-associated complication rate of 0.5%, ureteral injury rate of 0%, neurological injury rate of 1.9%, pseudarthrosis rate of 7.3%, and reoperation rate of 2.2%. CONCLUSION The L5-S1 level remains an important target for sagittal alignment in both degenerative and deformity surgery. The OLIF surgical corridor to this level presents special anatomic and clinical considerations and is a safe approach to minimize morbidity with minimally invasive access.

Applied anatomy and surgical technique of the lateral single-position L5-S1 fusion.

The latest development in the anterior lumbar interbody fusion (ALIF) procedure is its application in the lateral position to allow for simultaneous posterior percutaneous screw placement. The technical details of the lateral ALIF technique have not yet been described. To describe the surgical anatomy relevant to the lateral ALIF approach we performed a comprehensive anatomical study. In addition, the preoperative imaging, patient positioning, planning of the skin incision, positioning of the C-arm, surgical approach, and surgical technique are discussed in detail. The technique described led to the successful use of the lateral ALIF technique in our clinical cases. No lateral ALIF procedure needed to be aborted during these cases. Our present work gives detailed anatomical background and technical details for the lateral ALIF approach. This teaching article can provide readers with sufficient technical and anatomical knowledge to assist them in performing their first lateral ALIF procedure.

Retroperitoneal Exposure of the Anterior Lumbar Spine.

Anterior lumbar spine procedures such as anterior lumbar interbody fusion (ALIF) are used commonly to treat multiple pathologies, including pseudoarthrosis and degenerative disk disease. It is generally a safe and effective procedure, but an anterior approach to the lumbar spine requires critical navigation of the surgical window to avoid delicate structures. An operative technique should maximize the exposure without an increased risk of iatrogenic injury. To describe in detail a retroperitoneal exposure of the anterior lumbar spine. This surgical approach is a unique variation of standard anterior lumbar spine exposure techniques. This technique is described and illustrated in detail with an accompanying Supplemental Digital Content: video. Institutional Review Board (IRB) approval was not required because this is a variation of current techniques. Patient consent was obtained for the procedure and use of operative pictures and videos. Precise details of the technique are described. The surgical video demonstrates the technique for the L5-S1 ALIF approach. This technique is a novel variation of the standard retroperitoneal exposure of the anterior lumbar spine. The incision placement, size, and dynamic blunt retraction of this approach limit tissue disruption and provide an efficient exposure that has not been previously described in the literature.

Comparison of Different Approaches in Lumbosacral Spinal Fusion Surgery: A Systematic Review and Meta-Analysis.

We aimed to systematically review the literature to analyze the differences in posterior lumbar interbody fusion (PLIF), anterior lumbar interbody fusion (ALIF), and transforaminal lumbar interbody fusion (TLIF), focusing on the complications, risk factors, and fusion rate of each approach. Spinal fusion surgery is a well-established surgical procedure for a variety of indications, and different approaches developed. The various approaches and their advantages, as well as approach-related pathology and complications, are well investigated in spinal surgery. Focusing only on lumbosacral fusion, the comparative studies of different approaches remain fewer in numbers. We systematically reviewed the literature on the complications associated with lumbosacral interbody fusion. Only the PLIF, ALIF, or TLIF approaches and studies published within the last decade (2007–2017) were included. The exclusion criteria in this study were oblique lumbar interbody fusion, extreme lateral interbody fusion, more than one procedure per patient, and reported patient numbers less than 10. The outcome variables were indications, fusion rates, operation time, perioperative complications, and clinical outcome by means of Visual Analog Scale, Oswestry Disability Index, and Japanese Orthopaedic Association score. Five prospective, 17 retrospective, and two comparative studies that investigated the lumbosacral region were included. Mean fusion rates were 91,4%. ALIF showed a higher operation time, while PLIF resulted in greater blood loss. In all approaches, significant improvements in the clinical outcome were achieved, with ALIF showing slightly better results. Regarding complications, the ALIF technique showed the highest complication rates. Lumbosacral fusion surgery is a treatment to provide good results either through an approach for various indications as causes of lower back pain. For each surgical approach, advantages can be depicted. However, perioperative complications and risk factors are numerous and vary with ALIF, PLIF, and TLIF procedures, as well as with fusion rates.

61. ALIF vs TLIF for isthmic spondylolisthesis: differences in radiographic outcomes

BACKGROUND CONTEXT Patients with a diagnosis of isthmic spondylolisthesis have higher sacral slope, pelvic tilt, pelvic incidence and lumbar lordosis compared to patients without isthmic spondylolisthesis. Several fusion techniques have been used to treat isthmic spondylolisthesis in adults, including anterior lumbar interbody fusion (ALIF) and transforaminal interbody fusion (TLIF). Compared to other fusion techniques, ALIF has shown better sagittal alignment outcomes, particularly restoration of segmental lordosis. PURPOSE The purpose of this study was to evaluate which fusion technique provides the better radiological outcome for adult lumbar isthmic spondylolisthesis. STUDY DESIGN/SETTING This study was a retrospective analysis of prospectively collected data from a single, high-volume academic medical center. PATIENT SAMPLE Patients who underwent lumbar fusion for isthmic spondylolisthesis from 2014 to 2019 were included in the analysis. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, presented with a tumor or infection, or underwent revision surgery. OUTCOME MEASURES Preoperative and postoperative radiographic parameters were collected including sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, segmental lumbar lordosis, and the vertebral slip percentage. METHODS Patient and surgical characteristics including age, gender, smoking status, body mass index (BMI), Charlson Comorbidity Index (CCI), number of levels decompressed and number of levels fused were collected. Preoperative and final radiographic outcomes were obtained from an institutional electronic medical record. For analysis, patients were divided into two groups based on surgical technique: combined anterior fusion with posterior stabilization (ALIF-PLDF) or anterior and posterior fusion through a posterior approach (TLIF). RESULTS A total of 101 patients were included in final analysis, with 52 patients in the ALIF-PLDF group and 49 patients in the TLIF group. Mean age was greater in the TLIF group (p=0.017). Patients in the TLIF group were more likely to have a history of smoking (p=0.008), to have a greater CCI score (p=0.003), and to have higher number of levels decompressed. On analysis of radiographic parameters, preoperative sacral slope was higher in in the ALIF-PLDF group than the TLIF group (p=0.071). Postoperative overall lumbar lordosis was lower in the TLIF group (p=0.036). Postoperative segmental lumbar lordosis and the delta value for segmental lumbar lordosis were both lower in the TLIF group (p=0.030 and p=0.001). The TLIF group had a significant increase in PI-LL mismatch (p=0.032). Both groups had significant decrease in vertebral slip percent (p<0.001), which was measured by the magnitude of anterior-posterior translation with respect to the vertebral body below the defect. CONCLUSIONS Our data highlights that patients undergoing ALIF have a significant increase in segmental lordosis from their preoperative baseline. Interestingly, patients undergoing TLIF have significantly less postoperative change in segmental lumbar lordosis when compared to ALIF. When treating patients with isthmic spondylolisthesis, the ALIF approach has benefits not only in its capacity to restore segmental lordosis, but also by providing significant reduction in vertebral body slip. Our results suggest that, when compared to the TLIF approach, ALIF may be associated with better outcomes in terms of critical radiographic parameters. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Patients with a diagnosis of isthmic spondylolisthesis have higher sacral slope, pelvic tilt, pelvic incidence and lumbar lordosis compared to patients without isthmic spondylolisthesis. Several fusion techniques have been used to treat isthmic spondylolisthesis in adults, including anterior lumbar interbody fusion (ALIF) and transforaminal interbody fusion (TLIF). Compared to other fusion techniques, ALIF has shown better sagittal alignment outcomes, particularly restoration of segmental lordosis. The purpose of this study was to evaluate which fusion technique provides the better radiological outcome for adult lumbar isthmic spondylolisthesis. This study was a retrospective analysis of prospectively collected data from a single, high-volume academic medical center. Patients who underwent lumbar fusion for isthmic spondylolisthesis from 2014 to 2019 were included in the analysis. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, presented with a tumor or infection, or underwent revision surgery. Preoperative and postoperative radiographic parameters were collected including sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, segmental lumbar lordosis, and the vertebral slip percentage. Patient and surgical characteristics including age, gender, smoking status, body mass index (BMI), Charlson Comorbidity Index (CCI), number of levels decompressed and number of levels fused were collected. Preoperative and final radiographic outcomes were obtained from an institutional electronic medical record. For analysis, patients were divided into two groups based on surgical technique: combined anterior fusion with posterior stabilization (ALIF-PLDF) or anterior and posterior fusion through a posterior approach (TLIF). A total of 101 patients were included in final analysis, with 52 patients in the ALIF-PLDF group and 49 patients in the TLIF group. Mean age was greater in the TLIF group (p=0.017). Patients in the TLIF group were more likely to have a history of smoking (p=0.008), to have a greater CCI score (p=0.003), and to have higher number of levels decompressed. On analysis of radiographic parameters, preoperative sacral slope was higher in in the ALIF-PLDF group than the TLIF group (p=0.071). Postoperative overall lumbar lordosis was lower in the TLIF group (p=0.036). Postoperative segmental lumbar lordosis and the delta value for segmental lumbar lordosis were both lower in the TLIF group (p=0.030 and p=0.001). The TLIF group had a significant increase in PI-LL mismatch (p=0.032). Both groups had significant decrease in vertebral slip percent (p<0.001), which was measured by the magnitude of anterior-posterior translation with respect to the vertebral body below the defect. Our data highlights that patients undergoing ALIF have a significant increase in segmental lordosis from their preoperative baseline. Interestingly, patients undergoing TLIF have significantly less postoperative change in segmental lumbar lordosis when compared to ALIF. When treating patients with isthmic spondylolisthesis, the ALIF approach has benefits not only in its capacity to restore segmental lordosis, but also by providing significant reduction in vertebral body slip. Our results suggest that, when compared to the TLIF approach, ALIF may be associated with better outcomes in terms of critical radiographic parameters.

Spine stabilization is a risk factor for the development of pelvic iliac vein lesions

BackgroundOpen lumbar spine stabilization surgery often requires mobilization of the left and right common iliac veins (CIVs) and the placement of plates and screws that can impinge on them. We reviewed our venography experience of the past 3 years to determine whether there is an association between spine stabilization surgery and the development of symptomatic iliac vein outflow lesions. MethodsA retrospective chart review of prospectively collected data from our electronic medical record system was performed to identify patients who underwent venography with or without venous stenting and had a history of previous lumbar spine stabilization. Patients' demographics, medical comorbidities, venograms, and intravascular ultrasound (IVUS) data were collected and analyzed. The senior author reviewed all venograms and IVUS images of patients with previous spine stabilization procedures. ResultsFrom January 2014 to April 2018, venography was performed in 1713 limbs in 1245 patients at the Center for Vascular Medicine. Of the 1245 patients, 18 patients had a history of lumbar spine stabilization procedures: five anterior-posterior and 13 posterior. Nine had single-level and eight had two- or three-level fusions. All 18 patients demonstrated pelvic lesions. These included 1 left CIV aneurysm, 5 left CIV stenoses, 3 bilateral CIV stenoses, 2 left CIV and inferior vena cava occlusions, and 2 external iliac vein stenoses. The aneurysm patient was treated with anticoagulation, 8 patients underwent stenting, 1 patient refused stenting because of relocation to another country, 1 inferior vena cava-CIV occlusion could not be crossed, fear of dislodging a thrombus and the proximity to a protruding posteriorly placed screw prevented stenting in 2 patients, and 4 patients had a venoplasty alone because of undersizing of a stenosis or missed lesions with IVUS after review by a blinded reviewer. Lesions in anterior lumbar interbody fusion patients were extremely stenotic, required predilation, and resulted in a residual stenosis requiring venoplasty at a second setting in one patient. ConclusionsLumbar spine stabilization surgery may be a risk factor for development of symptomatic venous outflow obstruction lesions. During venography and stenting in patients with anterior lumbar interbody fusion approaches, significant scarring may be encountered, resulting in a residual stenosis after stent placement. Predilation venoplasty, before stent deployment, is recommended to prevent stent migration. Furthermore, a history of spine stabilization surgery in patients presenting with pelvic symptoms, lower extremity pain or swelling, or post-thrombotic symptoms should prompt consideration of a pelvic venous duplex ultrasound examination to determine whether an iliac venous outflow lesion is present.

Evolution of the Anterior Approach in Lumbar Spine Fusion

The anterior approach to lumbar spine fusion, termed anterior lumbar interbody fusion (ALIF), is becoming increasingly popular, with numerous recognized indications, well-defined advantages, and potential complications. From its first theoretical description in 1932 and the first operation published in 1933 to the more recently reported less invasive procedures, an anterior approach to the lumbar spine has many technical variations. Here we describe the evolution of the anterior approach to the lumbar spine, from a hugely invasive transperitoneal route to the current minimally invasive retroperitoneal approach. Many advantages have been advocated for the ALIF approach, and some issues about intraoperative and postoperative complications need to be evaluated in a more specific and homogeneous manner.

Comparing Radiographic Parameters for Single-Level L5-S1 Interbody Fusion: Anterior Lumbar (ALIF) Versus Transforaminal Lumbar Interbody Fusion (TLIF)

Abstract INTRODUCTION The lumbosacral junction acts as a transition point between the mobile lumbar spine and the rigid pelvis. It is thereby susceptible to degenerative changes necessitating fusion at L5-S1. In this study, we compared radiographic outcomes observed from single-level anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) at this level. METHODS Retrospective review of single-level ALIF and TLIF with up to one level PSF at L5-S1 between May 2007 and October 2018 was undertaken. X-ray measurements were gathered for lumbar lordosis, segmental lordosis, pelvic tilt, sacral slope, pelvic incidence, pelvic incidence-lumbar lordosis mismatch, anterior/posterior disc height, and sagittal vertical axis. Computed tomography /magnetic resonance imaging was used to determine central canal area, sagittal diameter, foraminal height, and foraminal area. RESULTS A total of 47 ALIF patients and 50 TLIF patients were included. Patients averaged 53.7 ± 10.1 yr of age for ALIF and 49.4 ± 14.7 yr old for TLIF (P = .094) with significant differences (P = .0017) seen with gender as ALIF had 60.4% males and TLIF 70.0% females. Single-level ALIF led to significantly (P = .0010) more segmental lordosis (+5.75° ± 7.31°) than TLIF (+0.25° ± 6.55°), though differences in lumbar lordosis were not statistically significant (P = .52). ALIF significantly increased both anterior (+10.4 ± 4.32 mm vs +4.30 ± 3.55 mm; P &lt; .0001) and posterior disc height (+4.33 ± 3.32 mm vs + 2.98 ± 2.07 mm; P = .043) than TLIF. Changes in sagittal vertical axis also significantly differed (P = .030) with ALIF decreasing sagittal vertical axis by 17.8 ± 26.4 mm from +60.3 mm to + 42.5 mm, and TLIF increasing by 0.95 ± 25.8 mm from 39.9 mm to 40.9 mm. Pelvic tilt, sacral slope, pelvic incidence, pelvic incidence-lumbar lordosis mismatch had no significant differences. No statistically significant differences were observed with central canal area, sagittal diameter, foraminal height or foraminal area between ALIF and TLIF. CONCLUSION At L5-S1, the ALIF approach leads to increased segmental lordosis, disc height, while also decreasing sagittal vertical axis to a significant degree than TLIF. However, these two approaches were no different with regards to pelvic parameters and measures of central canal and foraminal decompression.

Anterior lumbar interbody fusion (ALIF): biometrical results and own experiences

Lumbar fusion is a mainstay in the treatment of low back pain resulting from degenerative disc disease. Anterior lumbar interbody fusion (ALIF) has become a reasonable treatment technique to achieve indirect foraminal decompression with high fusion rates. The aim of the study was to analyse the biometrical parameters of the lumbar spine and the clinical outcome. The medical records of 51 patients treated with ALIF between 2012 and 2016 were retrospectively reviewed. Anterior and posterior disc height (DH), lumbar lordosis (LL), local disc angle (LDA) and foraminal dimensions were obtained on pre- and postoperative plain radiographs and computed tomography scans using ImageJ and Surgimap software according to the pedicle–pedicle technique. To evaluate the interbody fusion status on the last follow-up CT scans, we used Bridwell criteria. Preoperative and 12 months postoperative Oswestry Disability Index (ODI) scores were determined for all patients. The average length of hospitalisation was 4 days. Most of the patients had degenerative disc disease with foraminal stenosis. Five patients had early complications like paresthesia of lower limbs, sympathetic dysfunction or wound infections, but there were no major complications. Statistically significant (P < .01) improvement was observed in foraminal dimensions (area = 49%, height = 33% and width = 19%), anterior DH (49%), posterior DH (69%), LDA (47%) and LL (17.5%). Posterior DH correlated significantly with foramen height improvement. Radiographic evidence of fusion according to the modified Bridwell criteria (grade I and grade II) was observed in 96% (49/51) of the patients in the last CT of the lumbar spine. We also observed significant improvement in functional recovery in 94% of patients. The mini-open ALIF approach is a reasonable alternative to the more extensive posterior approaches. ALIF significantly restores the height of the intervertebral disc, indirectly increases foraminal dimensions, increases lordosis angle with significant short and long-term pain relief and functional recovery.

Minimally invasive anterior and lateral transpsoas approaches for closed reduction of grade II spondylolisthesis: initial clinical and radiographic experience.

OBJECTIVE Minimally invasive anterior and lateral approaches to the lumbar spine are increasingly used to treat and reduce grade I spondylolisthesis, but concerns still exist for their usage in the management of higher-grade lesions. The authors report their experience with this strategy for grade II spondylolisthesis in a single-surgeon case series and provide early clinical and radiographic outcomes. METHODS A retrospective review of a single surgeon's cases between 2012 and 2016 identified all patients with a Meyerding grade II lumbar spondylolisthesis who underwent minimally invasive lateral lumbar interbody fusion (LLIF) or anterior lumbar interbody fusion (ALIF) targeting the slipped level. Demographic, clinical, and radiographic data were collected and analyzed. Changes in radiographic measurements, Oswestry Disability Index (ODI), and visual analog scale (VAS) scores were compared using the paired t-test and Wilcoxon signed rank test for continuous and ordinal variables, respectively. RESULTS The average operative time was 199.1 minutes (with 60.6 ml of estimated blood loss) for LLIFs and 282.1 minutes (with 106.3 ml of estimated blood loss), for ALIFs. Three LLIF patients had transient unilateral anterior thigh numbness during the 1st week after surgery, and 1 ALIF patient had transient dorsiflexion weakness, which was resolved at postoperative week 1. The mean follow-up time was 17.6 months (SD 12.5 months) for LLIF patients and 10 months (SD 3.1 months) for ALIF patients. Complete reduction of the spondylolisthesis was achieved in 12 LLIF patients (75.0%) and 7 ALIF patients (87.5%). Across both procedures, there was an increase in both the segmental lordosis (LLIF 5.6°, p = 0.002; ALIF 15.0°, p = 0.002) and overall lumbar lordosis (LLIF 2.9°, p = 0.151; ALIF 5.1°, p = 0.006) after surgery. Statistically significant decreases in the mean VAS and the mean ODI measurements were seen in both treatment groups. The VAS and ODI scores fell by a mean value of 3.9 (p = 0.002) and 19.8 (p = 0.001), respectively, for LLIF patients and 3.8 (p = 0.02) and 21.0 (p = 0.03), respectively, for ALIF patients at last follow-up. CONCLUSIONS Early clinical and radiographic results from using minimally invasive LLIF and ALIF approaches to treat grade II spondylolisthesis appear to be good, with low operative blood loss and no neurological deficits. Complete reduction of the spondylolisthesis is frequently possible with a statistically significant reduction in pain scores.

Biomechanics of an Expandable Lumbar Interbody Fusion Cage Deployed Through Transforaminal Approach.

A novel expandable lumbar interbody fusion cage has been developed which allows for a broad endplate footprint similar to an anterior lumbar interbody fusion (ALIF); however, it is deployed from a minimally invasive transforaminal unilateral approach. The perceived benefit is a stable circumferential fusion from a single approach that maintains the anterior tension band of the anterior longitudinal ligament.The purpose of this biomechanics laboratory study was to evaluate the biomechanical stability of an expandable lumbar interbody cage inserted using a transforaminal approach and deployed in situ compared to a traditional lumbar interbody cage inserted using an anterior approach (control device). Twelve cadaveric spine specimens (L1-L5) were tested intact and after implantation of both the control and experimental devices in two (L2-L3 and L3-L4) segments of each specimen; the assignments of the control and experimental devices to these segments were alternated. Effect of supplemental pedicle screw-rod stabilization was also assessed. Moments were applied to the specimens in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). The effect of physiologic preload on construct stability was evaluated in FE. Segmental motions were measured using an optoelectronic motion measurement system. The deployable expendable TLIF cage and control devices significantly reduced FE motion with and without compressive preload when compared to the intact condition (p<0.05). Segmental motions in LB and AR were also significantly reduced with both devices (p<0.05). Under no preload, the deployable expendable TLIF cage construct resulted in significantly smaller FE motion compared to the control cage construct (p<0.01). Under all other testing modes (FE under 400N preload, LB, and AR) the postoperative motions of the two constructs did not differ statistically (p>0.05). Adding bilateral pedicle screws resulted in further reduction of ROM for all loading modes compared to intact condition, with no statistical difference between the two constructs (p>0.05). The ability of the deployable expendable interbody cage in reducing segmental motions was equivalent to the control cage when used as a stand-alone construct and also when supplemented with bilateral pedicle screw-rod instrumentation. The larger footprint of the fully deployed TLIF cage combined with preservation of the anterior soft-tissue tension band may provide a better biomechanical fusion environment by combining the advantages of the traditional ALIF and TLIF approaches.

Oblique Lumbar Interbody Fusion: Technical Aspects, Operative Outcomes, and Complications

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are commonly used approaches for lumbar spine fusion surgery, each with their own unique advantages and disadvantages. ALIF requires mobilization of the great vessels and peritoneum, and dissection of the psoas muscle in the LLIF technique is associated with postoperative neurologic complications in the proximal lower limb. The anterior-to-psoas (ATP) or oblique lumbar interbody fusion (OLIF) technique is the proposed solution to accessing the L1-L5 levels without the issues encountered with ALIF and LLIF. In this review, the technical nuances, operative outcomes, and complications with the ATP/OLIF technique in the current literature are summarized. A systematic search of the literature was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Data collected included operative time, blood loss, postoperative hospital stay, and complications, which were then pooled together. From the 16 studies selected, the mean blood loss was 109.9 mL, average operating time was 95.2 minutes, and mean postoperative hospital stay was 6.3 days. Fusion was achieved in 93% of levels operated. Incidence of intraoperative and postoperative complications was 1.5% and 9.9%, respectively. Transient thigh pain and/or numbness and hip flexion weakness occurred in 3.0% and 1.2% of patients, respectively. Early results on the ATP/OLIF technique are promising and warrant further investigation with well-designed prospective randomized studies to provide high-level evidence of the potential advantages over the ALIF and LLIF approaches.

Overpowering Posterior Instrumentation and Fusion using a Modified Anterior Lumbar Interbody Fusion Technique, An Experience of 11 Cases

IntroductionRestoration of sagittal balance is paramount in any type of spinal reconstructive surgery. Recent work has demonstrated that the failure to maintain lumbar lordosis following fusion not only accelerated adjacent degeneration (Umehara S. et al., Spine. 2000; Rothenfluh D.A. et al., Euro Spine. 2015), but also has a strong correlation to patient's clinical symptomatology, quality of life, and overall function (Glassman S.D. et al., Spine 2005; Schwab F. et al., Spine. 2010). As such, postoperative hypolordosis in the presence of posterior instrumentation and fusion has become a growing problem and presents the operative surgeon with a difficult challenge. In this study we describe our early clinical experience with using a modified anterior lumbar interbody fusion (ALIF) technique for the purposes of increasing lumbar lordosis and improving sagittal imbalance in revision adult spinal deformity patients. Material and MethodsWe present a retrospective case series of 11 patients that developed pain and disability following previous instrumented posterior lateral spinal fusion. All patients were diagnosed with either a posterior pseudoarthrosis and/or a lumbar segment fused with non-anatomic segmental lordosis. All patients underwent ALIF with either anterior wedge allograft or hyperlordotic cages and posterior instrumentation and fusion. Distraction of the disc space and obtainment of the desired lordosis was achieved by using the jackknife capability of the OR table (the patients lumbosacral junction was positioned at the level of the hinge of the table and during the discectomy the table was “jackknifed” into further lordosis). This provided a gradual, and controlled generation of a more anatomic lordosis. Digital standard upright lateral radiographs were used to measure spinopelvic parameters on all patients both pre-, and post-operatively. Two independent observers reviewed each radiograph. ResultsFrom 2014 to 2015, 11 patients underwent revision surgery utilizing this modified ALIF approach with hyperlordotic graft insertion and revision posterior fusion for the treatment of symptomatic sagittal imbalance. Mean patient age was 50.1 years (range 30 – 62). All patients had 30-degree hyperlordotic cages placed while three had an additional standard 20-degree cage placed at an additional lumbar level (average 1.3 per patient). Although preliminary, early postoperative radiographic assessment has shown average increase in L5/S1 segmental and global lumbar lordosis exceeding 20 and 7 degrees, respectively. Additionally, pelvic incidence was found to be increase by an average of 5 degrees. ConclusionThe ability to overpower the posterior instrumentation and to generate added lordosis while fusing the anterior spine is an appealing prospect. In our small series, no loosening of the pedicle screws, or fracture of the pedicles/posterior fusion was observed. We hypothesize that the correction occurs due to flexibility of the titanium bars. Although this is a small series and caution should be exercised before widespread uptake, it does illustrate the potential use of this technique to further address this challenging patient population.

Single-level lumbar pyogenic spondylodiscitis treated with mini-open anterior debridement and fusion in combination with posterior percutaneous fixation via a modified anterior lumbar interbody fusion approach.

This study evaluated the efficacy and safety of mini-open anterior debridement and lumbar interbody fusion in combination with posterior percutaneous fixation for single-level lumbar pyogenic spondylodiscitis. This is a retrospective study. Twenty-two patients with single-level lumbar pyogenic spondylodiscitis underwent mini-open anterior debridement and lumbar interbody fusion in combination with posterior percutaneous fixation via a modified anterior lumbar interbody fusion (ALIF) approach. Patients underwent follow-up for 24 to 38 months. Clinical data, etiological examinations, operative time, intraoperative blood loss, American Spinal Injury Association (ASIA) grade, Japanese Orthopaedic Association (JOA) lumbar function score, visual analog scale (VAS) score, Oswestry Disability Index (ODI), postoperative complications, and the bony fusion rate were recorded. The mean operative time was 181.1 ± 22.6 minutes (range 155-240 minutes). The mean intraoperative blood loss was 173.2 ± 70.1 ml (range 100-400 ml). Infection was found in lumbar vertebrae L2-3, L3-4, and L4-5 in 2, 6, and 14 patients, respectively. Bacterial cultures were positive in 15 patients, including 4 with Staphylococcus aureus, 6 with Staphylococcus epidermidis, 4 with Streptococcus, and 1 with Escherichia coli. Postoperative complications included urinary retention, constipation, and numbness in the thigh in 5, 3, and 2 patients, respectively. Compared with before surgery, the VAS scores and ODI were significantly lower at the final follow-up, the JOA scores were significantly higher, and the ASIA grades had improved. All patients achieved good intervertebral bony fusion. Mini-open anterior debridement and lumbar interbody fusion in combination with posterior percutaneous fixation via a modified ALIF approach results in little surgical trauma and intraoperative blood loss, acceptable postoperative complications, and is effective and safe for the treatment of single-level lumbar pyogenic spondylodiscitis. This approach could be an alternative to the conventional open surgery.

Microscopically Assisted versus Standard Laparotomy L5–S1 Circumferential Fusion

Introduction Microscopically assisted retroperitoneal laparotomy is a minimally invasive modification of a standard approach for anterior lumbar interbody fusion (ALIF). In this study, we compare the peri- and immediate postoperative results of standard versus microscopically assisted L5–S1 interbody fusion. Patients and Methods A total of 20 patients with low back pain because of the degenerative disc disease and/or spondylolisthesis were included in the study. Overall, 10 patients were submitted to a single-stage microscopically assisted left-retroperitoneal interbody fusion and 10 patients were submitted to a single-stage standard left-retroperitoneal interbody fusion. All patients were instrumented posteriorly with screw and rod system. Data were collected for vascular and visceral injuries, blood loss, operating time, walk-out-of-bed time, peristalsis recovery, and initial 48 hours pain levels. Results Significant differences were found for vascular lesion and blood loss between the two groups with the standard laparotomy group being on the worse side. Furthermore, patients subjected to a microscopically assisted approach showed a more rapid recovery of intestinal peristalsis, a reduced walk-out-of-bed time, and a lower intensity of perceived pain in the first 48 hours after the surgery. Conclusion The results of this study indicate the minimally invasive approach for ALIF as an equally efficient but much safer approach as compared with the standard laparotomy approach. Reduction of complications and a shorter in-hospital stay contribute on lowering the costs of the treatment making it not only clinically, but also economically more suitable surgical choice.

Biomechanical Comparison of Anterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion

An in vitro biomechanical comparison of 2 fusion techniques, anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF), on cadaveric human spines. To compare the immediate construct stability, in terms of range of motion (ROM) and neutral zone, of ALIF, including 2 separate approaches, and TLIF procedures with posterior titanium rod fixation. Both ALIF and TLIF have been used to treat chronic low back pain and instability. In many cases, the choice between these 2 techniques is based only on personal preference. No biomechanical performance comparison between these 2 fusion techniques is available to assist surgical decision. Twelve cadaveric lumbar motion segments were loaded sinusoidally at 0.05 Hz and 5 Nm in unconstrained axial rotation, lateral bending and flexion extension. Specimens were randomly divided into 2 groups with 6 in each group. One group was assigned for TLIF whereas the other group for ALIF. In the ALIF group, there were 3 steps. First, the lateral ALIF procedure with the anterior longitudinal ligament (ALL) intact was performed. Afterwards, the ALL was cut without removing the ALIF cage. Finally, another appropriately sized ALIF cage was inserted anteriorly. Biomechanical tests were conducted after each step. In the ALIF group, the lateral ALIF and subsequent anterior ALIF reduced segmental motion significantly (P=0.03) under all loading conditions. Removing the ALL increased ROM by 59% and 142% in axial rotation and flexion extension, respectively (P=0.03). The anterior ALIF approach was able to achieve similar biomechanical stability of the lateral approach in lateral bending and flexion extension (P>0.05) under all loading conditions. The TLIF procedure significantly reduced the range of motion compared with the intact state (P=0.03). However, no statistical difference was detected between the TLIF group and the ALIF group (P>0.05). Both ALIF and TLIF procedures combined with posterior instrumentation significantly improved construct stability of intact spinal motion segments. However, there was no statistical difference between these 2 fusion techniques. The 2 ALIF approaches (lateral and anterior) also had similar construct stability even though anterior longitudinal ligament severing significantly reduced stability.