Lateral Transpsoas Interbody Fusion Research Articles

Single Position Lateral versus Prone Transpsoas Lateral Interbody Fusion Inclusive of L4-L5: A Single Surgeon Experience Examining Early Postoperative Outcomes

The transpsoas lateral lumbar interbody fusion (LLIF) procedure is a minimally invasive lumbar spine approach that provides indirect neural decompression, improved sagittal alignment, and a high fusion rate. Typically accompanied by posterior pedicle screw insertion, there has been interest in performing LLIF in a single position to decrease cost and time under anesthesia. However, there is a paucity of direct comparisons between single-position LLIF via prone versus lateral decubitus positioning. Therefore, this stud aims to compare the outcomes of a single surgeon performing prone versus lateral single-position LLIF, inclusive of the L4-L5 level. A retrospective review was performed of a consecutive case series of patients who underwent either prone or lateral, single-position LLIF by a single surgeon All cases involved the L4-L5 level. Demographic data, perioperative details, clinical outcomes, and pre- and postoperative lumbar lordosis were recorded. 63 patients underwent lateral, and 16 patients underwent prone single-position LLIF. Demographics and average interbody size were similar between groups. Operative time, change in lumbar lordosis, and length of hospital stay did not differ between the two positions. Both groups performed similarly in terms of pre- and postoperative VAS pain score, and complications. Patients who underwent lateral position LLIF ambulated farther on postoperative day 1 (250 vs. 200 feet, p=0.015). Average time to follow up was 53 weeks. This study demonstrates promising preliminary results indicating that single-position LLIF performs well, even at the L4-L5 level, in both the prone and lateral positions.

446 Utility of Intraoperative Motor-Evoked Potential in L4-5 Lateral Lumbar Interbody Fusion: 3-Year Prospective Study

INTRODUCTION: Nerve injury has been reported as high as 23% in direct transpsoas lateral interbody fusion (LLIF), particularly at L4-5. METHODS: This is a prospective, observational, cohort study of consecutive patients who underwent L4-5 LLIF in a 3-year interval from 2018 to 2020. Spontaneous and triggered EMG, somatosensory evoked potentials (SSEP) were routinely recorded. In addition MEPs from quadriceps and anterior tibialis muscle groups were also recorded bilaterally. Transcranial MEP were recorded every 5 minutes from the time of incision. A decrease in amplitude of 50% or more from baseline was considered a positive result, and the surgeon was alerted accordingly. Patient’s neurological exam and health related quality of life measures were collected preoperatively, immediately postoperatively, and at the time of follow up at 6 weeks, 3 months, 6 months, 1 and 2 years. RESULTS: 72 patients were included. Transient quadriceps weakness occurred in 13 patients but resolved by 6 weeks. 30 patients had a significant decrease in MEP amplitude without changes in spontaneous or triggered EMG and SSEP. Two patients had persistent dorsiflexion weakness (3/5 and 1/5) at 2 year follow up. One patient had persistent quadriceps (4-/5) and dorsiflexion (4/5) weakness at 1 year follow up. One patient the surgery was aborted at the time of introduction of retractor due to 69% reduction in MEP and inability to mitigate the changes. All instances of MEP changes were noted during retraction phase. No patient with a negative MEP developed weakness postoperatively. At predetermined level of 50% decrease of amplitude, MEP was 100% sensistive and 65% specific in detecting neural injury. CONCLUSION: MEP monitoring provides additional value to sEMG, tEMG, and SSEP during LLIF at L4-5 to avoid injury. The value of MEP is primarily during maintenance of retraction and not during traversing the psoas muscle where EMG is most valuable.

Single-Position Prone Transpsoas Lateral Interbody Fusion Including L4L5: Early Postoperative Outcomes

The lateral lumbar interbody fusion (LLIF) was a revolutionary approach devised by Luiz Pimenta that allowed the surgeon to access the lumbar spine through the major psoas muscle. Although the traditional LLIF had enabled enormous advances, the technique has its drawbacks. A new concept to perform the traditional LLIF has been proposed, with the patient being prone to decubitus with slightly extended legs. Our study aims to analyze the early outcomes of patients who had undergone the prone transpsoas (PTP) for degenerative spine pathologies including the L4/5 level. This study was multicentric, retrospective, nonrandomized, noncomparative, and observational. Only participants who received PTP in L4/5, with no more than 3 levels of intersomatics and fixation no further than S1, were included. The primary outcomes were the onset of new neurologic deficits and postoperative complications. Also, surgery details, such as blood loss and surgery duration, were measured. Neurologic deficits were accessed at the postoperative visit, which ranged from 7 to 14 days after surgery. Twenty-seven patients fulfilled the inclusion and exclusion criteria, with the majority receiving PTP only in L4/5 (66.6%). The mean surgery time was 182, with 29 minutes of mean transpsoas time. Of the patients, only 1 presented the onset of a motor deficit, while 3 patients presented a new sensory deficit. Five complications occurred, none intraoperative and 5 postoperative, with only 1 directly correlated with the access. The prone transpsoas is safe and feasible for approaching the L4/5 disk, presenting with a low rate of complication and new-onset neurologic deficits.

Multistage Hybrid Approach to Management of Significant Sagittal Malalignment: 2-Dimensional Operative Video.

Minimally invasive surgery (MIS) approaches for the correction of adult spinal deformity have gained popularity in the past decade. MIS approaches can result in decreased hospitalization times and decreased morbidity. However, compared to open techniques, MIS approaches are challenging in the setting of fixed sagittal deformity and strategic surgical staging. Combined MIS and miniopen techniques are described as "hybrid" techniques. We report on the surgical approach for a fixed sagittal deformity using both MIS and miniopen techniques, specifically a miniopen pedicle subtraction osteotomy (PSO) and an anterior column release (ACR). The patient gave written informed consent for surgical treatment; institutional review board approval was not required. The patient first underwent the placement of percutaneous modular pedicle screws from T12 to the pelvis as well as a mini-PSO across the previously fused L5 vertebral body, with the placement of a temporary rod. The following day, the patient underwent lateral transpsoas interbody fusion and ACR at L2/3; a percutaneous rod was then passed from T12 to the pelvis for segmental fixation. The patient recovered well and was discharged home without complication 6 d after the initial day of surgery. The combined use of surgical staging and traditional open techniques in a selective, minimalistic fashion and adherence to minimally invasive principles provide for a powerful set of surgical techniques that capitalize on less invasive approaches to deformity management. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

109. Radiographic predictors of indirect neural decompression in minimally invasive transpsoas lateral interbody fusion

BACKGROUND CONTEXT An advantage of lateral interbody fusion (LLIF) surgery is the resultant indirect decompression of the neural elements that occurs with disc height restoration, restoration of spinal alignment and ligamentotaxis. The degree to which indirect decompression of the spinal canal occurs varies patient to patient, and there remains no method for effectively predicting which patients will or will not respond. PURPOSE In this study, we identify pre- and postoperative predictive factors of radiographic indirect decompression of the central spinal canal. The goal is to help surgeons ascertain which patients best respond to indirect decompression in the setting of lateral interbody fusion. STUDY DESIGN/SETTING This is a retrospective evaluation of a prospectively and consecutively collected cohort of patients treated for degenerative etiologies at a single institution. PATIENT SAMPLE Patients were included if they received a minimally invasive lateral transpsoas interbody fusion by a single surgeon at our institution. Patients were treated for degenerative etiologies. OUTCOME MEASURES A retrospective evaluation of prospectively collected consecutive patients treated with LLIF surgery treated at a single institution without subsequent direct decompression was performed. Pre- and postoperative MRI imaging was used to grade canal stenosis and three-dimensional volumetric reconstructions were used to measure changes in the central canal area (CCA). METHODS Multivariate regression was used to identify predictive variables that correlated with increases in CCA. Independent assessments of canal measurements were made by a blinded board-certified neuroradiologist and a spine surgeon. RESULTS Sixty-six patients with 110 levels were treated with a mean age of 68 years. Forty-six levels (42%) were treated for DDD, 36 levels (33%) for spondylolisthesis, 11 levels (10%) for adjacent segment disease and 17 levels (15%) for deformity. Preoperatively, 19 patients had moderate (29%) and 18 had severe stenosis (27%) with the remainder having mild or no stenosis. Of these 37 patients, only 4 remained severe, 4 were moderate and the rest (78%) improved to mild or no stenosis. CCA increased 41% from a mean of 1.09 to 1.55 cm2 (p 0.05). Multivariate evaluation of predictive variables identified that preoperative anterolisthesis (p=0.002), the presence of vacuum disc phenomenon (p=0.049) and preoperative segmental lordosis (p=0.009) were independently associated with percentage increase in CCA. Age, body mass index, side of approach, pedicle screw fixation, facet grading score, presence of facet effusions, preoperative anterior and posterior disc heights, implant distance from the posterior aspect of the vertebral body and implant height all were not associated (p>0.05). CONCLUSIONS LLIF successfully achieves indirect decompression of the CCA radiographically with a mean change of 41%. Preoperative anterolisthesis on standing films, the presence of vacuum disc phenomenon on computed tomography and preoperative segmental lordosis were independently predictive factors for the percentage increase in CCA that can be achieved. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

The Effect of Alendronate on Subsidence After Lateral Transpsoas Interbody Fusion: A Preliminary Report.

Success after lateral transpsoas interbody fusion (LLIF) partially depends on avoidance of subsidence to maintain spinal alignment, disc space height, and indirect neural decompression. Techniques for preventing subsidence have focused largely on surgical and biomechanical properties of spinal reconstruction; however, medical management may also affect subsidence rates as well. The purpose of this study is to examine the effect of alendronate on minimally invasive LLIF patients with regard to radiographic and catastrophic subsidence. We followed 26 patients who had LLIF at the L4-5 level (13 on alendronate, 13 control) and 22 patients at the L3-4 level (10 on alendronate, 12 control). Radiographs were reviewed to obtain measurements of subsidence at the 4 corners of the cage at 3 follow-up time points (2-3, 5-8, and 10-12 months). A Tobit mixed model was used to confirm the results. We found no relationship between alendronate and subsidence for L3-4 fusion. At L4-5 we observed increased subsidence in the control group compared to the alendronate group (difference = 0.07 cm, 95% confidence interval [CI]: -0.01, 0.16, P = .08). There was a decrease in subsidence noted for the alendronate group for each time period (differences: 2-3: -0.06 cm, 95% CI: -0.28, 0.15], P = .27; 5-8: -0.14 cm, 95% CI: -0.36, .08, P = .10; 10-12: -0.21 cm, 95% CI: -0.48, .04, P = .05). A clear reduction in subsidence was found with the use of postoperative alendronate in patients undergoing L4-5 LLIF. Alendronate had a significant decrease in subsidence at L4-5 after 10-12 months as compared to the control group. Additionally, no patients treated with alendronate had catastrophic subsidence. These data suggest the need for further study of alendronate in the prevention of subsidence after LLIF. 3.

Anatomic Considerations in the Lateral Transpsoas Interbody Fusion: The Impact of Age, Sex, BMI, and Scoliosis.

This is a retrospective case series. Define the anatomic variations and the risk factors for such within the operative corridor of the transpsoas lateral interbody fusion. The lateral interbody fusion approach has recently been associated with devastating complications such as injury to the lumbosacral plexus, surrounding vasculature, and bowel. A more comprehensive understanding of anatomic structures in relation to this approach using preoperative imaging would help surgeons identify high-risk patients potentially minimizing these complications. Age-sex distributed, naive lumbar spine magnetic resonance imagings (n=180) were used to identify the corridor for the lateral lumbar interbody approach using axial images. Bilateral measurements were taken from L1-S1 to determine the locations of critical vascular, intraperitoneal, and muscular structures. In addition, a subcohort of scoliosis patients (n=39) with a Cobb angle >10 degrees were identified and compared. Right-sided vascular anatomy was significantly more variant than left (9.9% vs. 5.7%; P=0.001). There were 9 instances of "at-risk" vasculature on the right side compared with 0 on the left (P=0.004). Age increased vascular anatomy variance bilaterally, particularly in the more caudal levels (P≤0.001). A "rising-psoas sign" was observed in 26.1% of patients. Bowel was identified within the corridor in 30.5% of patients and correlated positively with body mass index (P<0.001). Scoliosis increased variant anatomy of left-sided vasculature at L2-3/L3-4. Nearly all variant anatomy in this group was found on the convex side of the curvature (94.2%). Given the risks and complications associated with this approach, careful planning must be taken with an understanding of vulnerable anatomic structures. Our analysis suggests that approaching the intervertebral space from the patient's left may reduce the risk of encountering critical vascular structures. Similarly, in the setting of scoliosis, an approach toward the concave side may have a more predictable course for surrounding anatomy. Level 3-study.

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

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

Analysis of Cost and 30-Day Outcomes in Single-Level Transforaminal Lumbar Interbody Fusion and Less Invasive, Stand-Alone Lateral Transpsoas Interbody Fusion

A comparative evaluation of operative costs between single-level transforaminal interbody fusion (TLIF) and stand-alone lateral transpsoas interbody fusion (LIF) has not yet been done. We analyzed the costs, operative parameters, and early outcomes of single-level stand-alone LIF versus single-level TLIF. Ten patients who underwent single-level TLIF and 10 patients who underwent single-level stand-alone LIF were included in the analysis. Total, variable, and fixed costs from perioperative data were available from a single institution. In addition, patient demographics, length of hospital stay, and 30-day outcomes and readmission rates were reviewed. Total cost, variable cost, and fixed costs were significantly lower in the LIF group, and there was no difference in outcomes. Single-level stand-alone LIF may prove to be more cost-effective and provide cost savings with analogous 30-day outcomes compared with single-level TLIF procedures.

Minimally Invasive Lateral Transpsoas Interbody Fusion at the L4/5 Level: A Review of 61 Consecutive Cases.

Reported complication rates for minimally invasive lateral transpsoas interbody fusion (MIS-LIF) vary widely. The risk of lumbar plexus injury is particularly concerning at the L4-5 disc space. We report our experience with MIS-LIF at L4-5, and discuss the risk profile of transpsoas approaches at this level. To evaluate safety of MIS-LIF at the L4/5 level. This was a retrospective, IRB-approved cohort study performed at a single institution from 2011 to 2016. Patients who underwent MIS-LIF at L4-5 were included. Patients with multilevel fusions were excluded. We analyzed postoperative sensory and motor deficits, the date of resolution, health-related quality-of-life scores, and rate of fusion. Over a 5-yr period, 303 patients underwent MIS-LIF at our institution. Sixty-one patients had surgery only at the L4-5 level (20.1%). Twelve of these patients (19.6%) had postoperative neurological deficits including 2 motor deficits (2/61=3.2%) and 11/61 (18%) sensory deficits. At 12-mo follow-up, 3 of the deficits persisted for a long-term complication rate of 3/61 (4.9%), motor complication 2/61 (3.2%). Hospital stay and follow-up averaged 2.1 d and 15 mo. Average Oswestry Disability Index improved from 51.1 to 31.1 (P<.00001). Visual Analog Scale (VAS) improved from 7.4 to 3.9 (P<.016). There were no reoperations secondary to hardware failure or pseudoarthrosis. Fusion rate was 89% at 12 mo. MIS-LIF is a safe and effective approach for interbody fusion at L4-5 with low rate of lumbar plexus injury. Most immediate postoperative deficits will resolve over time.

Comparison of Stand-Alone, Transpsoas Lateral Interbody Fusion at L3-4 and Cranial vs Transforaminal Interbody Fusion at L3-4 and L4-5 for the Treatment of Lumbar Adjacent Segment Disease

Retrospective cohort study. To compare outcomes and complications of stand-alone minimally invasive lateral interbody fusion (LIF) vs revision posterior surgery for the treatment of lumbar adjacent segment disease. Adults who underwent LIF or transforaminal lumbar interbody fusion (TLIF) for adjacent segment disease were compared. Exclusion criteria: >grade 1 spondylolisthesis, posterior approach after LIF, and L5/S1 surgery. Patient demographics, estimated blood loss, hospital length of stay, complications, reoperations, health-related quality of life measures, and radiographs were examined. Data were analyzed with the χ2, Wilcoxon signed rank, and Mann-Whitney U tests. A total of 17 LIF and 16 TLIF patients were included. Demographics were similar. Follow up was similar (LIF: 22.9 ± 11.8 months vs TLIF: 22.0 ± 4.6 months; P = .86). The LIF patients had significantly less blood loss (LIF: 36 ± 16 mL vs TLIF: 700 ± 767 mL; P < .001) and shorter length of stay (LIF: 2.6 ± 2.9 days vs TLIF: 3.3 ± 0.9 days; P = .001). There were no intraoperative complications. Revision rate was 4 of 17 in LIF and 3 of 16 in TLIF (P = .73). Baseline health-related quality of life and radiographic measurements were similar. In both groups, back and leg pain scores significantly improved, and in LIF, the Owestry Disability Index, and EuroQol-5D significantly improved. The LIF had a significant increase in intervertebral height (LIF: 4.8 ± 2.9 mm, P < .001, TLIF: 1.3 ± 3.4 mm, P = .37), which was significantly greater for LIF than TLIF (P = .002). Similarly, LIF had a significant increase in segmental lordosis (LIF: 5.6° ± 4.9°, P < .001, TLIF: 3.6° ± 8.6°, P = .16), which was not significantly different between groups. Patients with adjacent segment disease may receive significant benefit from stand-alone LIF or TLIF. The LIF offers advantages of less blood loss and a shorter hospital stay. 3.

A psoas splitting approach developed for outpatient lateral interbody fusion versus a standard transpsoas approach.

The technique of transpsoas lateral interbody fusion has been adopted to avoid direct anterior interbody fusion, but lateral fusions have been limited to disc spaces above L5 and are associated with neurologic injuries especially to the lumbar plexus when approaching L4-5. The authors aim to demonstrate a psoas splitting technique to decrease risk of complications associated with the standard transpsoas technique. Medical records of 84 patients with prospectively collected data reviewed. Two groups created 44 patients with standard lateral transpsoas approach (group 1) and 40 patients with psoas splitting approach (group 2). The psoas splitting approach utilizes two blades placed anteriorly and posteriorly to split the psoas fibers anteriorly while keeping the posterior blade docked in place where it enters the psoas muscle. The cephalocaudal blades sit above the psoas muscle measuring 30-40 mm shorter than the posterior docking blade. Thirty-nine males and 45 females, age range 31-71 years, average 58±2 years. Average body mass index (BMI) was 28.4±1.1 kg/m2. Mean preoperative standard approach Oswestry disability index (ODI) increased from 48.4±3.0 to 55.2±4.0 compared to psoas splitting approach preoperative ODI means reduced from 45.1±5.0 to 34.9±6.0 (P=0.010). Group 1 mean preoperative visual analogue scale (VAS) score improved from 7.8±0.3 to 3.8±0.6 compared to group 2 mean preoperative VAS score which improved from 7.2±0.4 to 2.7±0.5 (P=0.048). Major complication rate of 20.5% was noted in standard transpsoas approach patients, including inability to walk and dermatome numbness. The outcomes of this study have shown that patients who had lateral lumbar interbody fusion (LLIF) with the psoas splitting approach had statistically significant improvement in ODI scores compared to the standard approach. Fusion was achieved in all patients and there was no evidence of implant failure or subsidence. In the psoas splitting group the major complication rate was only 5%.

The cost effectiveness of minimally invasive spine surgery in the treatment of adult degenerative scoliosis: a comparison of transpsoas and open techniques

INTRODUCTIONSurgical treatment improves quality of life in patients with adult degenerative scoliosis (ADS). However, open ADS surgeries are complex, large magnitude operations associated with a high rate of complications. The lateral transpsoas interbody fusion technique is a less invasive alternative to open ADS surgery, but less invasive techniques tend to be more expensive. The objective of this study was to evaluate the cost effectiveness of the transpsoas technique for patients with ADS over a 12-month time horizon from a public payer perspective. METHODSA cost-effectiveness analysis was performed based on a consecutive case series of patients who underwent ADS surgeries between 2006 and 2012. Effectiveness was expressed as the difference in patient reported preoperative and 12-month postoperative health-related quality of life (HRQOL), which was measured in quality-adjusted life years. Health-care resource use was tabulated based on a clinical chart review on an item-by-item basis. Unit cost data were obtained from published provincial costs in Alberta, Canada. All costs were adjusted to 2015 Canadian dollars. The base case analysis included costs for the surgery, initial hospitalization, and treatment for complications over a 12-month follow-up period. The uncomplicated case analysis included costs for the surgery and initial hospitalization only. The joint uncertainty surrounding the cost and HRQOL differences was estimated using bootstrapping with 10,000 replicates. RESULTSA total of 10 open technique and 12 transpsoas technique T11–pelvis fusions were included in the analysis. In the base case analysis, the transpsoas technique was less costly compared with the open technique, total cost of $83,513 (95% CI: $72,772–$94,253) versus $111,381 (95% CI: $36,340–$186,423), respectively (incremental cost $27,869), and was associated with 0.06 more quality-adjusted life years and/or patient. However, in the uncomplicated case, the open technique was less costly compared with the transpsoas technique ($47,795 [95% CI: $39,003–$56,586] vs $76,510 [95% CI: $72,273–$80,746]), respectively, with an incremental cost of $28,715. Based on the probabilistic analysis of 10,000 bootstrap iterations for the base case analysis, the transpsoas technique was more effective and less costly compared with the open technique 57% of time. One-way deterministic sensitivity analysis by adjusting bone-morphogenetic protein-2 dosage further improved cost effectiveness of the transpsoas technique by lowering overall costs. CONCLUSIONSTranspsoas surgeries were associated with better outcomes in terms of HRQOL and lower costs over 1-year follow-up period compared with more invasive open technique. This study should be viewed as a pilot evaluation and should be replicated in a larger prospective multicenter controlled study.

Variation in Psoas Muscle Location Relative to the Safe Working Zone for L4/5 Lateral Transpsoas Interbody Fusion: A Morphometric Analysis.

The safe working zone for lateral access to the L4/5 disc space has been said to lie in the anteroposterior (AP) midpoint of the disc space due to the location of the femoral nerve at that level. However, the AP location of the psoas muscle (and thus the lumbosacral plexus within) at L4/5 is variable. A psoas muscle lying excessively anteriorly at the L4/5 disc space may preclude safe access to the L4/5 disc space from a lateral transpsoas approach. Lumbar spine magnetic resonance imaging (MRI) for 300 consecutive patients at the authors' institution were reviewed retrospectively. The AP distance between the ventral aspect of the thecal sac and the dorsal aspect of the psoas muscle at L4/5 was measured, as was the AP diameter of the L4/5 disc space. The dorsal aspect of the psoas muscle at L4/5 was most commonly found dorsal to the ventral aspect of the thecal sac (zone P, N= 145; 48.3%), whereas it was found at the junction of zones IV/P in 37 patients (12.3%), in zone IV in 85 patients (28.3%), in zone III in 29 patients (9.7%), and in zone II in 4 patients (1.3%). The location of the psoas muscle in relation to the L4/5 disc space is somewhat variable. In 11% of patients, the dorsal-most aspect of the psoas muscle was located within zones II or III, likely precluding safe access to the L4/5 disc space from a lateral transpsoas approach.

Comparison of the safety outcomes between two surgical approaches for anterior lumbar fusion surgery: anterior lumbar interbody fusion (ALIF) and extreme lateral interbody fusion (ELIF).

To review the evidence on safety of anterior lumbar interbody fusion (ALIF) and extreme lateral transpsoas interbody fusion (ELIF) in the treatment of degenerative spinal disorders with an emphasis on the association between neuromonitoring and complications. We performed a systematic literature search in the Cochrane (CENTRAL), MEDLINE, EMBASE and the FDA Medical Devices databases. We abstracted information on study design, sample size, population, procedure, number and location of involved levels, follow-up time and complications, as well as information on conflict of interest and source of funding. In addition, for ELIF we collected information on the use of neuromonitoring during the procedure. 34 publications were included in the review: 24 ELIF (all case series), 9 ALIF (8 randomized controlled trials and 1 case series) and one retrospective cohort that directly compared ELIF with ALIF. 18 out of 24 ELIF studies reported using neuromonitoring. The overall complication rate for ELIF was lower compared to ALIF without FDA reports (16.61 vs. 26.47%, respectively). However, the rate of neurologic complications in ELIF was almost twice as high compared to ALIF without FDA reports (8.92 and 4.96%, respectively). The rate of overall complications in ELIF studies that were reported using neuromonitoring was lower compared to the studies that did not report using neuromonitoring (16.34 vs. 21.74%, respectively). Although the overall complications rate for ELIF was lower compared to ALIF, ELIF is associated with a greater risk of neurological complications compared to ALIF even when used with neuromonitoring.

Anterior column realignment following lateral interbody fusion for sagittal deformity correction.

Degenerative and iatrogenic diseases may lead to loss of lordosis or even kyphotic thoracolumbar deformity and sagittal misalignment. Traditional surgery with three-column osteotomies is associated with important neurologic risks and postoperative morbidity. In a novel technique, the lateral transpsoas interbody fusion (LTIF) is complemented with the sacrifice of the anterior longitudinal ligament and anterior portion of the annulus followed by the insertion of a hyperlordotic interbody cage. This is a less invasive lateral technique named anterior column realignment (ACR) and aims to correct sagittal misalignment in adult spinal deformity (ASD), with or without the addition of minor posterior osteotomies. In this article, we provide an account of the evolution to the ACR technique, the literature, and the Brazilian experience in the treatment of adult spinal deformity with this novel advanced application of LTIF. In the presence of ASD, the risk-to-benefit ratio of a surgical correction must be evaluated. Less invasive surgical strategies can be alternatives to treat the deformity and provide better quality of life to the patient. ACR is an advanced application of lateral transpsoas approach, up to date has shown to be reliable and effective when used for ASD, and may minimize complications and morbidity from traditional surgical procedures. Long-term follow-up and comparative studies are needed to evaluate real benefit.

Saphenous Nerve Somatosensory Evoked Potentials Monitoring during Lateral Interbody Fusion

Introduction Lateral transpsoas interbody fusion (LIF) is a novel minimally invasive technique reducing risks related to traditional anterior approaches. Despite advantages, transpsoas exposure carries up to 30% risk of lumbar plexus injury. Intraoperative neuromonitoring is utilized to prevent postoperative deficits, but to date there is no reliable technique to detect upper lumbar plexus injury. Materials and Methods Saphenous nerve somatosensory-evoked potentials (SSEPs) were obtained by stimulation of inferior medial thigh with needle electrodes and recording from scalp. Primary outcome was measured by testing reproducibility of SSEPs at baseline, changes during procedure, and relevance to standard modalities. Intraoperative changes were identified and correlated to primary outcome. Results A total of 38 patients were included in the study (average age 63.5 years, 25 females, 13 males) and underwent surgery on 88 total levels. Reliable saphenous SSEPs were recorded bilaterally in 34 of 38 patients. Reduction of amplitude &gt; 50% in two cases was observed during expansion of the tubular retractor. The posterior tibial SSEP remained unchanged. The saphenous returned to baseline after collapsing the retractor and no clinical deficits were observed. Conclusion Saphenous SSEPs can be used to detect electrophysiological changes to prevent femoral nerve injury during LIF. A larger sampling size is underway as to validate whether this technique offers increased sensitivity/specificity, and correlates with the postoperative outcomes.

Systematic Review of Thigh Symptoms after Lateral Transpsoas Interbody Fusion for Adult Patients with Degenerative Lumbar Spine Disease.

Lateral transpsoas interbody fusion (LTIF) is a minimally invasive technique for achieving lumbar spinal fusion. While it has many advantages over open techniques it carries with it a distinct set of risks, most commonly post-operative ipsilateral thigh pain, weakness and sensory disturbances. It is vital for both the surgeon and patient to understand the risks for and outcomes of injury associated with this procedure. We conducted a systematic review of the literature to evaluate the incidence, risks, and long-term clinical outcomes of post-operative thigh symptoms in patients treated with LTIF. We conducted a search of MEDLINE, EMBASE, CINAHL, Scopus, Web of Science and the Cochrane Collaboration Library, using keywords and MeSH terms, for English-language literature published through September 2014, as well as reference lists from key articles. Studies were then manually filtered to retrieve articles that met inclusion criteria. We were interested in studies that reported postoperative lower extremity symptoms after LTIF, such as pain, weakness and changes in sensation. The strength of evidence was determined based on precepts outlined by the Grades of Recommendation Assessment, Development and Evaluation Working Group (GRADE). A total of 392 articles were initially retrieved, with 24 ultimately meeting criteria for inclusion. The incidence of any post-operative thigh symptom varied, ranging as high as 60.7%, with 9.3% of patients experiencing a motor deficit related to direct nerve injury. Several studies reported cases of persistent symptoms at 6 months follow up. Additionally, inclusion of the L4-5 disc space and a longer duration of surgery were both identified as risks for developing postoperative thigh symptoms. The risk of postoperative thigh symptoms after LTIF is high. Thigh pain, paresthesias and weakness were the most commonly reported symptoms. While most patients' symptoms resolved by 6 months follow up, several studies reported patients with symptoms persistent as far as 12 months removed from surgery. Surgery at the L4-5 disc space and longer surgical duration place the patient at greater risk for developing postoperative and long-term thigh symptoms.

Caseload midwifery program at Westmead Hospital: An evaluation of the first 1000 births outcomes

A comparative evaluation of operative costs between single-level transforaminal interbody fusion (TLIF) and stand-alone lateral transpsoas interbody fusion (LIF) has not yet been done. We analyzed the costs, operative parameters, and early outcomes of single-level stand-alone LIF versus single-level TLIF.Ten patients who underwent single-level TLIF and 10 patients who underwent single-level stand-alone LIF were included in the analysis. Total, variable, and fixed costs from perioperative data were available from a single institution. In addition, patient demographics, length of hospital stay, and 30-day outcomes and readmission rates were reviewed.Total cost, variable cost, and fixed costs were significantly lower in the LIF group, and there was no difference in outcomes.Single-level stand-alone LIF may prove to be more cost-effective and provide cost savings with analogous 30-day outcomes compared with single-level TLIF procedures.

Stand-alone minimally invasive lateral lumbar interbody fusion: Multicenter clinical outcomes

Stand-alone minimally invasive lateral transpsoas interbody fusion (MIS-LIF), without posterior instrumentation, is feasible because the technique does not necessitate the disruption of the stabilizing elements. The objectives of this study are to evaluate the efficacy and clinical outcomes of patients who underwent stand-alone lateral interbody fusion. A multicenter chart review was conducted to identify patients who underwent stand-alone MIS-LIF between 2008 and 2012. Patients were classified by spinal pathology (degenerative disc disease [DDD], spondylolisthesis [SL] and adult degenerative scoliosis [ADS]). Routine clinical follow-up was scheduled at 3, 6, and12months. Outcome measures included hospital length of stay, fusion rates, neurologic complications, integrity of construct and clinical outcome questionnaires (Visual Analog Scale [VAS] and Oswestry Disability Index [ODI]). A total of 59 patients met the inclusion criteria. The average age was 60years (range 31–86years). Spinal pathologies treated were DDD in 37 (63%), SL in four (7%) and ADS in 18 (30%) patients. Fusion rate was 93% of patients (95% of levels) at 12months. Two patients required re-operation. Mean hospital stay and follow-up were 3.3days (range 1–10) and 14.6months, respectively. The mean preoperative VAS and ODI were 69.1 and 51.8, respectively. VAS improved to 37.8 (p<0.0005). ODI improved to 31.8 (p<0.0005). Seventy percent of patients had grade 0 subsidence while 30% had grade I and grade II subsidence. Stand-alone MIS-LIF is viable option in a carefully selected patient population for both single and multilevel disease and shows significant improvement in health related quality of life.