2-level Transforaminal Lumbar Interbody Fusion Research Articles

Restoring L4-S1 Lordosis Shape in Severe Sagittal Deformity: Impact of Correction Techniques on Alignment and Complication Profile

Severe sagittal plane deformity with loss of L4-S1 lordosis is disabling and can be improved through various surgical techniques. However, data is limited on the differing ability of anterior lumbar interbody fusion (ALIF), pedicle subtraction osteotomy (PSO), and transforaminal lumbar interbody fusion (TLIF) to achieve alignment goals in severely malaligned patients. To examine surgical techniques aimed at restoring L4-S1 lordosis in severe adult spinal deformity (ASD). Retrospective review of prospectively collected data. A total of 96 patients who underwent ALIF, PSO, and TLIF were included in this study. The following data were observed for all cases: patient demographics, spinopelvic parameters, complications, and PROMs. Severe ASD patients with preoperative PI-LL >20°, L4-S1 lordosis <30°, and full body radiographs and patient-reported outcome measures (PROMs) at baseline and six-week postoperative visit were included. Patients were grouped into ALIF (1-2 level ALIF at L4-S1), PSO (L4/L5 PSO), and TLIF (1-2 level TLIF at L4-S1). Comparative analyses were performed on demographics, radiographic spinopelvic parameters, complications, and PROMs. Among the 96 included patients, 40 underwent ALIF, 27 underwent PSO, and 29 underwent TLIF. At baseline, cohorts had comparable age, sex, race, Edmonton frailty scores and radiographic spinopelvic parameters (p>0.05). However, PSO was performed more often in revision cases (p<0.001). Following surgery, L4-S1 lordosis correction (p=0.001) was comparable among ALIF and PSO patients and caudal lordotic apex migration (p=0.044) was highest among ALIF patients. PSO patients had higher intraoperative estimated blood loss (p<0.001) and motor deficits (p=0.049), and in-hospital ICU admission (p=0.022) and blood products given (p=0.004) but were otherwise comparable in terms of length of stay, blood transfusion given, and postoperative admission to rehab. Likewise, 90-day postoperative complication profiles and six-week PROMs were comparable as well. ALIF can restore L4-S1 sagittal alignment as powerfully as PSO, with fewer intra-operative and in-hospital complications. When feasible, ALIF is a suitable alternative to PSO and likely superior to TLIF for correcting L4-S1 lordosis among patients with severe sagittal malalignment.

Completely Minimally Invasive Implant Removal and Transforaminal Lumbar Interbody Fusion for Adjacent Segment Disease: Case Series and Operative Video.

Adjacent segment disease is a relatively common late complication after lumbar fusion. If symptomatic, certain patients require fusion of the degenerated adjacent segment. Currently, there are no posterior completely minimally invasive techniques described for fusion of the adjacent segment above or below a previous fusion. We describe here a novel minimally invasive technique for both implant removal (MIS-IR) and adjacent level transforaminal lumbar interbody fusion (MIS-TLIF) for lumbar stenosis. Demographic, surgical, and radiographic outcome data were collected for patients with lumbar stenosis and previous lumbar fusion, who were treated with MIS-IR and MIS-TLIF through the same incision. Radiographic outcomes were assessed postoperatively and complications were assessed at the primary end point of 3 months. A total of 14 patients (7 female and 7 male), with average age 64.6 years (SD 13.4), were included in this case series. Nine patients had single-level MIS-IR with single-level MIS-TLIF. Three patients had 2-level MIS-IR with single-level MIS-TLIF. Two patients had single-level MIS-IR with 2-level MIS-TLIF. Only 1 patient had a postoperative complication-hematoma requiring same-day evacuation. There were no other complications at the primary end point and no fusion failure at the hardware removal levels to date (average follow-up, 11 months). Average increases in posterior disk height and foraminal height after MIS-TLIF were 4.44, and 2.18 mm, respectively. Minimally invasive spinal IR can be successfully completed along with adjacent level TLIF through the same incisions, via an all-posterior approach.

Ehlers-Danlos Syndrome is Associated with Increased Rates of Adjacent Segment Disease Following TLIF: A Propensity Matched Study

Ehlers-Danlos syndrome (EDS) is a collection of connective tissue disorders which are often associated with tissue laxity and disc degeneration. However, the implications of EDS on the risk of adjacent segment disease (ASD) after transforaminal lumbar interbody fusion (TLIF) are not well described. The objective of this study is to compare the rates of ASD among patients with EDS and those without EDS. Patients who underwent 1-3 level TLIF for degenerative disc disease between 2010-2022 were identified using the PearlDiver Mariner all-claims insurance database. Patients with all types of EDS were included. Patients undergoing surgery for tumors, trauma, or infection were excluded. 1:1 propensity matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with ASD in a linear regression model. The primary outcome measure was the development of ASD. The secondary outcomes were the development of pseudoarthrosis, medical complications, and surgical complications. Propensity matching resulted in 2 equal groups of 85 patients who did or did not have EDS and underwent 1-3 level TLIF. Patients without EDS were less likely to experience ASD (RR 0.18, 95% CI 0.09-0.35, P < 0.001). There was no significant difference between the 2 patient groups with regards to a diagnosis of pseudoarthrosis, and there was no significant difference for all-cause medical and surgical complications between the 2 patient groups. After propensity matching to control for confounding variables, the findings of this study suggest that EDS may be associated with an increased risk of ASD following TLIF. Future studies are needed to corroborate these findings.

Promotion of higher rates of early fusion using activated titanium versus polyetheretherketone cages in adults undergoing 1- and 2-level transforaminal lumbar interbody fusion procedures: a randomized controlled trial.

There is ongoing debate on the relative benefits and drawbacks of polyetheretherketone (PEEK) versus titanium (Ti) in generating a bone-to-implant surface microenvironment conducive to osseointegration. Micro- and nanoscale internal and topographic cage modifications have recently been posited to facilitate osseointegration and fusion, but human in vivo confirmation remains lacking. The authors of this study sought to directly compare early radiological outcomes in adults undergoing 1- and 2-level transforaminal lumbar interbody fusion (TLIF) procedures using either PEEK or nano-etched Ti interbody cages with an incorporated microlattice structure. Patients were enrolled in a single academic center using a single-blind randomized controlled superiority design. Screening was undertaken from a pool of consecutive patients eligible for TLIF to undergo placement in a 1:1 ratio of either lordotic PEEK or activated Ti cages at each level of 1- or 2-level procedures. An a priori power analysis was performed and a preplanned interim analysis was undertaken once 50 of 70 patients were enrolled. Patient study data were collected perioperatively and uploaded to a Research Electronic Data Capture (REDCap) registry. Interbody fusion was assessed based on 6-month postoperative lumbar dual-energy CT (DECT) studies using the method of Brantigan and Steffee, as modified to describe the Fraser definition of locked pseudarthrosis (Brantigan-Steffee-Fraser [BSF] scale). In the final cohort of 50 patients, 40 interbody levels implanted with PEEK cages were compared with 34 interbody levels with activated Ti cages. The trial was stopped early given the results of an interim analysis with respect to the primary outcome. Surgical parameters including number of levels treated, average cage height, and position were not different between groups. For the PEEK and activated Ti groups, 20.6% versus 84.0% demonstrated BSF grade 3 fusion on 6-month postoperative DECT imaging (p < 0.001). Subsidence at 6 months on DECT was identified in 12 (41.4%) of PEEK levels versus 5 (20.8%) of activated Ti levels (p < 0.001). BSF-3 grading was predictive of segmental stability and numeric rating scale (NRS) leg pain improvement at 1 year postoperatively. Oswestry Disability Index and NRS back and leg pain scores all improved similarly in both cohorts at 1 year postoperatively. Activated Ti interbody cages mediate early fusion at significantly higher rates with lower rates of subsidence as compared with PEEK cages. These findings support the idea that interbody cage microscale properties, including surface topography, may play a primary role in facilitating osseointegration and fusion.

Does Preoperative Modic Changes Influence the Short-term Fusion Rate of Single Level Transforaminal Lumbar Interbody Fusion?-a Matched-pair Case Control Study.

At present, the influence of Modic changes (MCs) on postoperative fusion rate of lumbar interbody fusion (LIF) is mainly focused on the medium- and long-term fusion rate, while the short-term fusion rate has not been reported. The aim of this study was to compare the short-term fusion rate of lumbar degenerative disease patients with and without MCs after single level transforaminal lumbar interbody fusion (TLIF). In this retrospective and matched-pair case control study, we included 100 patients who underwent TLIF from January 2017 to January 2020 and had at least two follow-up visits over a two-year period. Fifty patients with MCs (MCs group) were matched with 50 patients without MCs (non MCs group) for age, sex, surgical level, diagnosis, operative time, and intraoperative blood loss. We collected the X-ray and computed tomography (CT) data of patients from 3 months to 2 years after the operation to assess bony fusion and the cage union ratio. According to the type of cage, the MCs group was further divided into the nano-hydroxyapatite/polyamide 66 (n-HA/PA66) group and polyetheretherketone (PEEK) group, and the fusion performance between the two groups was compared. Finally, age, sex, body mass index (BMI), smoking and cage type were included in the logistic regression model for risk factor analysis. The bony fusion rates in the MCs group at 3 months, 6 months, 1 year and 2 years after surgery were significantly lower than those in the non MCs group (P < 0.05) (23.8% vs 62.5%, 52.6% vs 78.9%, 61.1% vs 83.3%, 74.0% vs 90.0%). The average coronal cage union ratios of the upper and lower endplates in the MCs group were significantly lower than those in the non MCs group (54.3% ± 17.5% vs 75.0% ± 17.2%, P < 0.05; 73.3% ± 12.0% vs 84.9% ± 8.0%, P < 0.05). Similarly, analogous results were obtained by comparing the MCs and non MCs groups' three-dimensional CT sagittal plane images (62.5% ± 16.5% vs 76.1% ± 12.4%, P < 0.05; 67.0% ± 13.9% vs 79.8% ± 11.5%, P < 0.05). Short-term fusion rates were lower in the MCs group than in the non MCs group. The coronal and sagittal cage union ratio in the MCs group was lower than that in the non MCs group. The fusion performance of n-HA/PA66 and PEEK cages in the MCs group was comparable.

Biplanar Expandable Cages for Transforaminal Lumbar Interbody Fusion Are Safe and Achieve Good 1-Year Clinical and Radiological Outcomes in an Asian Population.

This study investigated 1-year clinical and radiological outcomes of biplanar expandable (BE) cages following transforaminal lumbar interbody fusion (TLIF) in an Asian population. A retrospective review was conducted of all consecutive patients who underwent TLIF with BE cages performed by 2 fellowship-trained spine surgeons from 2020 to 2021. Inclusion criteria included open or minimally invasive (MIS) TLIF, of up to 3 spinal segments, performed for treatment of degenerative disc disease, spondylolisthesis, or spinal stenosis. Patient-reported outcomes, including visual analog score (VAS) for back and lower limb pain, Oswestry Disability Index (ODI) and North American Spine Society neurogenic symptom score (NSS), and various radiographic parameters, were evaluated. A total of 23 patients underwent TLIF with BE cages with a follow-up duration of 1.25 years. Of those patients, 7 (30%) underwent 1-level TLIF, 12 (52%) underwent 2-level TLIF, and 4 (18%) underwent 3-level TLIF, with a total of 43 spinal segments fused. Four patients (17%) underwent MIS TLIF while 19 patients (83%) underwent open TLIF. VAS for back pain scores improved by 4.8 ± 3.4 (P < 0.001) from 6.5 ± 2.6 to 1.7 ± 2.2; VAS for lower limb pain scores improved by 5.2 ± 3.8 (P < 0.001) from 5.7 ± 3.4 to 0.5 ± 1.6; ODI scores improved by 29.0 ± 18.1 (P < 0.001) from 49.4 ± 15.1 to 20.4 ± 14.2; and NSS scores improved by 36.8 ± 22.1 (P < 0.001) from 53.3 ± 21.1 to 16.5 ± 19.8. Significant improvements in radiological parameters included increase in anterior disc height, posterior disc height, foraminal height, segmental lordosis, and lumbar lordosis. There were no implant-related complications, cage subsidence, cage migration, or revision surgery at 1 year. TLIF performed with BE cages led to significantly improved patient-reported outcomes and radiographic parameters at 1 year and is safe for use in Asians. The results of this study support the effectiveness and safety of TLIF with biplanar expandable cages.

Preoperative Oswestry Disability Index Cannot Reliably Predict Patient Satisfaction After Single and Double Level Lumbar Transforaminal Interbody Fusion Surgery.

The role of patient-reported outcomes in preoperative assessment is not well studied. There is recent interest in studying whether Patient-reported outcomes scores can be used either independently, or in conjunction with clinical findings, in the assessment of patients for surgery. To investigate if improvement in clinically significant scores correlate with post-operative patient satisfaction in 1-2 level transforaminal lumbar interbody fusion (TLIF) surgery. We also aim to define a threshold Oswestry Disability Index (ODI) which correlate with achieving post-operative MCID and patient satisfaction. 1001 patients who underwent single or double level TLIF (Minimally invasive and Open) in our institution with at least 2years follow up were included in this study. We studied self-reported measures including patient satisfaction and ODI score. At 2-year follow-up, the overall mean ODI score improved from 49.7 ± 18.3 to 13.9 ± 15.2 (P < 0.001) with 74.6% of patients meeting the MCID. Patient satisfaction was achieved in 95.3% of all patients. In the MIS group, the preoperative cut-off was determined to be 37.2 at maximal Youden index associated with AUC of 0.72 (95% CI 0.65-0.86). In the open group, the preoperative cut-off was determined to be 37.2 at maximal Youden index associated with AUC of 0.70 (95% CI 0.62-0.77). Using the preoperative cut-offs found, there was no significant difference in patient satisfaction in both MIS and open groups. Overall, our patients undergoing TLIF had good 2-year ODI score improvement and patient satisfaction after surgery. While meeting the MCID for ODI score correlates with patients' satisfaction postoperatively, 75% of patients not meeting the MCID for ODI score remained satisfied with the surgery. We are unable to define a threshold pre-operative ODI which correlates with achieving post-operative MCID and patient satisfaction.

Modified Frailty Index Does Not Provide Additional Value in Predicting Outcomes in Patients Undergoing Elective Transforaminal Lumbar Interbody Fusion

To determine the predictive value of the modified Frailty Index (mFI) in evaluating sarcopenia and clinical outcomes in patients undergoing 1-level or 2-level transforaminal lumbar interbody fusion (TLIF). Patients who underwent a 1-level or 2-level TLIF between 2012 and 2020 were retrospectively identified. Frailty was compared among groups using mFI, and sarcopenia was classified by the psoas muscle cross-sectional area. Bivariate statistics compared demographics, comorbidities, and clinical outcomes. A linear regression model was developed using the Charlson Comorbidity Index (CCI) or mFI as independent variables to determine potential predictors for improvement in 1-year patient-reported outcomes. Of 488 included patients, 60 were severely frail and 60 patients had sarcopenia, but sarcopenia was not associated with patient frailty (P= 0.469). Severely frail patients had worse baseline Oswestry Disability Index (ODI) (P < 0.001), Mental Component Score-12 (P= 0.001), and Physical Component Score-12 (P < 0.001), and worse improvement in ODI (P= 0.037), Physical Component Score-12 (P < 0.001), and visual analog scale (VAS) back (P= 0.007). mFI was an independent predictor of poorer improvement in VAS back and ODI, whereas age+ CCI in addition predicted poorer improvement in VAS leg. Patients with higher mFI experienced longer length of stay, less frequent home discharge, and higher rates of complications, but similar readmission and reoperation rates. Frailer patients experience poorer improvement in back pain, physical functioning, and disability after TLIF. mFI and the combination of age and CCI comparably predict patient-reported outcomes but do not correlate to baseline sarcopenia. Frailty increased the risk of complications, length of hospital stay, and risk of nonhome discharge.

Awake spinal fusion: a retrospective analysis of minimal invasive single level transforaminal lumbar interbody fusion done under spinal anaesthesia in 150 cases

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: Spinal anaesthesia carries the advantage of having rapid onset, lesser blood loss, early recovery and hospital stay as compared to general anaesthesia. The present study evaluated outcomes of awake spinal fusion i.e., minimal invasive single level transforaminal lumbar interbody fusion (MIS-TLIF) under spinal anaesthesia. Current study is a retrospective analysis of prospectively collected data carried to assess patient related outcome benefits for a single level transforaminal lumbar interbody fusion done under spinal anaesthesia.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods&lt;/strong&gt;: Patients who fit deemed criteria not responding to 6 weeks of conservative treatment to lumbar degenerative pathologies underwent MIS-TLIF. The demographic data, visual analogue pain scale (VAS), Oswestry disability index (ODI), blood loss, time from entering operation theatre to time of incision, time of bandaging to exit from operation theatre, time of stay in post anaesthesia care unit (PACU), duration of surgery, nausea/vomiting, urinary retention, requirement of analgesics, duration of stay in hospital, peri-operative complications, fusion rate and satisfaction score were compiled and assessed.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; 150 patients were operated with MISTLIF under spinal anaesthesia. VAS and ODI score improved significantly at final follow up (p&amp;lt;0.05). The mean duration of surgery was 148±18.24 minutes and blood loss were 109.64±110.45 ml. The average time from entering OT to incision and bandaging to exit was respectively 27.32±8.44 and 6.43±3.28 minutes. Mean PACU time was 36.74±6.32 minutes while duration of stay averaged 1.58±0.67 days. Post operative analgesia requirement was in 10.6% patients and radiographic fusion was observed in 96.6% patients. 90.6% patients were fully satisfied with spinal anaesthesia.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Awake spinal fusion should be considered as a novel surgical approach with newer minimal invasive surgical techniques and regional anaesthesia to improve patient satisfaction and overall surgical outcome.&lt;/p&gt;

Radiological and Clinical Outcomes comparing 2-level MIS Lateral and MIS Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spinal Stenosis.

Retrospective Cohort Study. To compare early postoperative radiological and clinical outcomes between 2-level minimally invasive (MIS) trans-psoas lateral lumbar interbody fusion (LLIF) and MIS transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar spinal stenosis. Fifty three consecutive patients undergoing 2-level lumbar interbody fusion from L3-L5 for degenerative lumbar spinal stenosis were enrolled. Twenty four patients underwent LLIF and 29 underwent TLIF. Operative time and length of stay were similar between LLIF and TLIF (272.8 ± 82.4 vs 256.1 ± 59.4 minutes; 5.5 ± 2.8 vs 4.7 ± 3.3 days, P > .05), whereas blood loss was lower for LLIF (229.0 ± 125.6 vs 302.4 ± 97.1mls, P = .026). Neurological deficits were more common in LLIF (9 vs 3, P = .025), whereas persistent deficits were rare for both (1 vs 1, P = 1). For both groups, all patient reported outcomes visual analogue scale (VAS back pain, VAS leg pain, ODI, SF-36 physical) improved from preoperative to 2-years postoperative (P < .05), with both groups showing no significant differences in extent of improvement for any outcome. Lateral lumbar interbody fusion demonstrated superior restoration of disc height (L3-L4: 4.1 ± 2.4 vs 1.2 ± 1.9mm, P < .001; L4-L5: 4.6 ± 2.4 vs .8 ± 2.8mm, P < .001), foraminal height (FH) (L3-L4: 3.5 ± 3.6 vs 1.0 ± 3.6mm, P = .014; L4-L5: 3.0 ± 3.5 vs -.1 ± 4.4mm, P = .0080), segmental lordosis (4.1 ± 6.4 vs -2.1 ± 8.1°, P = .005), lumbar lordosis (LL) (4.1 ± 7.0 vs -2.3 ± 12.6°, P = .026) and pelvic incidence-lumbar lordosis (PI-LL) mismatch (-4.1 ± 7.0 vs 2.3 ± 12.6°, P = .019) at 2-years follow-up. The superior radiological outcomes demonstrated by 2-level trans-psoas LLIF did not translate into difference in clinical outcomes compared to 2-level TLIF at the 2-years follow-up, suggesting both approaches are reasonable for 2-level lumbar interbody fusion in degenerative lumbar spinal stenosis.

442 Cage Type in Short Segment Transforaminal Lumbar Interbody Fusions is Associated With Alterations in Foraminal Height, but Not Clinical Outcomes

INTRODUCTION: Steerable “banana” cages have been shown to increase index level segmental lordosis in short-segment transforaminal lumbar interbody fusion (TLIF) procedures. The same is not true for straight “bullet” cages. While this increase in lordosis is generally thought to be advantageous, a theoretical complication is decreased foraminal height leading to worsened clinical outcomes. METHODS: We retrospectively reviewed one- and two- level TLIFs at a single tertiary care center between 2012 and 2020 with minimum one-year follow-up. Patient report outcome measures (PROMs), revision rates, and radiographic measurements were compared between two cohorts based on cage morphology. RESULTS: 48 patients with 56 straight and 93 patients with 129 steerable cages were identified. Steerable cages were associated with an increase in index level segmental lordosis (7.7 vs 11.8°, p &lt; 0.001) and a decrease in foraminal height (20.3 vs 18.4 mm, p &lt; 0.001). Straight cages were associated with a decrease in index level lordosis (8.2 vs 6.3, p = 0.004) and no significant change in foraminal height (19.5 vs 20.2 mm, p = 0.08). Despite these differences, both cohorts reported improved NRS leg, NRS back, RAND SF-36 pain, RAND SF-36 physical functioning, and ODI scores at last follow-up (p = 0.005). One-year revision rates were similar (straight - 4.2%, steerable - 2.2%, p = 0.88) between cohorts. CONCLUSION: Steerable cages are associated with increased index level segmental lordosis and decreased foraminal height after TLIF. Straight cages are associated with decreased segmental lordosis, but do not correlate with a significant change in foraminal height. Both cage types are associated with significantly improved clinical outcomes.

Efficiency of Spinal Anesthesia versus General Anesthesia for Minimal Invasive Single Level Transforaminal Lumbar Interbody Fusion: A Retrospective Analysis of 178 Patients

Objective: To evaluate the efficacy of spinal anesthesia in patients undergoing minimal invasive single level transforaminal lumbar interbody fusion surgery (MIS TLIF) and to compare the results with that of general anesthesia.Method: 178 patients were included in the study, 86 were in general anesthesia and 92 were in spinal anesthesia. Patients aged between 20 to 70 years who had undergone MIS-TLIF not responding to 6 weeks of conservative treatment were included. The routine steps of anesthesia for both general and spinal anesthesia were adhered. The VAS, blood loss, duration of surgery, time from entering operation theatre to time of incision, time of bandaging to exit from operation theatre, time of stay in Post Anesthesia Care Unit (PACU), nausea/vomiting, urinary retention, duration of stay in hospital, peri-operative complications were compiled and assessed. Appropriate statistical analysis was applied.Results: The mean time for entering the operation theatre to the incision; mean time from bandaging to the exit; mean PACU time and the mean hospital stay were significantly lower in the spinal anesthesia group (p&lt;0.05). The other parameters are comparable except, urinary retention which was significantly higher in spinal anesthesia group (p&lt;0.05). Conclusion: Spinal anesthesia offers efficient operating room functioning with decreasing overall operation theatre time. It is very efficient alternative technique to general anesthesia which can be considered for elective lumbar surgeries with a lower late of adverse events especially at lower lumbar levels.

Contribution of Multilevel Transformainal Lumbar Interbody Fusion Surgery to Restoration of Lumbar Lordosis in Patients with Degenerative Spine: Comparison of Long and Short Level Fusion.

To investigate the effect of multilevel transforaminal lumbar interbody fusion (TLIF) procedures in lumbar degenerative spine conditions on the restoration of lumbar lordosis (LL) in patients with short- and long-level fusion, and to examine the associated radiological results. This retrospective study reviewed patients with degenerative spinal diseases who underwent lumbar fusion using a multilevel TLIF procedure. Patients with three or fewer segments involved in fusion were assigned to the shortlevel fusion group and those with more than three segments involved in fusion were assigned to the long-level fusion group. The anteroposterior and lateral spine radiographs of the patients were used to measure LL, distal lumbar lordosis and radiological parameters. The study included 47 patients who met the inclusion criteria, with a mean age of 60.4 ± 12.2 years. The mean follow-up time of our patients was 18.3 ± 11 months. Thirty-five (74.5%) patients were women and 12 (25.5%) were men. Overall, 12 patients underwent 3-level and 35 patients underwent 2-level TLIF. Long-level fusion was performed in 24 patients and short-level fusion was performed in 23 patients. Multilevel TLIF can be used to correct spinopelvic alignment when applied with the appropriate indications and techniques in patients with degenerative spinal disorders. Multilevel TLIF is associated with substantial improvements in LL, distal lumbar lordosis, and SVA (sagittal vertical axis). It also helps to correct the correlation between PI and LL.

Enhanced recovery after surgery (ERAS) for open transforaminal lumbar interbody fusion: a retrospective propensity-matched cohort study

BACKGROUNDThe enhanced recovery after surgery (ERAS) protocol is a multidisciplinary, multimodal approach which has been shown to facilitate recovery of physiological function, and reduce postoperative pain, complication rates, and length of stay without adversely affecting readmission rates. Design and implementation of ERAS protocols in the recent spine surgery literature has primarily focused on patients undergoing minimally invasive lumbar surgery. However, conventional open transforaminal lumbar interbody fusion (TLIF) remains a common procedure and to date there are no studies assessing an ERAS protocol in this patient population. PURPOSEThis study presents a single surgeon experience implementing an ERAS protocol in patients undergoing 1- or 2-level open TLIF. STUDY DESIGN/SETTINGRetrospective consecutive patient cohort with controls propensity-matched for age, body mass index, sex, and smoking status. PATIENT SAMPLEConsecutive patients that underwent 1- or 2-level open TLIF for degenerative disease from 12/2018 – 02/2021 and controls from 12/2011-12/2017 by a single surgeon. ERAS was implemented in December 2018. OUTCOME MEASURESPrimary: length of stay; Secondary: first day to ambulate, first day to bowel movement, first day to void, daily average and maximum pain scores, opioid use, discharge disposition, 30-day readmission rate, and re-operations. METHODSDemographic, perioperative, clinical, radiographic data were collected. Multivariate mixed-linear regression models were developed for length of stay, physiological function, pain scales, and opiate use. RESULTSThere were 114 patients included with 57 in each cohort. After propensity matching, patient characteristics were similar between groups. Operative time decreased significantly after institution of ERAS (170±44 vs. 141±37 minutes, p <.0001) as did length of stay (4.6±1.7 vs. 3.6±1.6 days, p<.0001). First day of ambulation, bowel movement, and bladder voiding improved by 0.8 (p<.0001), 0.7 (p=.008), and 0.8 (p<.0001) days, respectively, in the ERAS cohort. Total daily intravenous morphine milligram equivalent (MME) (8±9 vs. 36±38, p<0.0001) and total 72-hour MME consumption (53±33 vs. 68±48, p<.0001) was significantly lower in the ERAS cohort; however, 72-hour MME consumption was not found to be significantly different in a sensitivity analysis controlling for preoperative MME. Average daily pain scores were similar between groups. CONCLUSIONSConsistent with other studies demonstrating benefit of an ERAS protocol for minimally invasive spine procedures, ERAS was associated with decreased operative time, reduced length of stay, decrease in IV opioid consumption, and improved physiological outcomes for open 1- and 2-level TLIF. ERAS can be a potentially effective strategy for improving patient outcome and efficiency of healthcare resources for common conventional spinal surgeries such as open TLIF.

PEEK Versus Titanium Static Interbody Cages: A Comparison of 1-Year Clinical and Radiographic Outcomes for 1-Level TLIFs.

This was a retrospective cohort study. This study evaluates the patient-reported Health Related Quality of Life outcomes and radiographic parameters of patients who underwent a single level transforaminal lumbar interbody fusion with either a polyetheretherketone (PEEK) or titanium interbody cage. Spinal stenosis with instability is a common diagnosis that is often treated with interbody fusion, in particular transforaminal lumbar interbody fusion. Titanium and PEEK interbody cage properties have been extensively studied to understand their effect on fusion rates and subsidence. A retrospective cohort study was conducted from a single, high volume, academic hospital. Health Related Quality of Life outcomes were obtained from Outcomes Based Electronic Research Database and electronic medical record chart review. Subsidence was defined as a loss of 2 mm or more in the anterior or posterior disk height. Spinopelvic alignment parameters measured were sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, segmental lordosis, and pelvic incidence-lumbar lordosis mismatch. Fusion rates were assessed by the Brantigan-Steffee criteria. The study included a total of 137 patients (108 PEEK, 29 titanium). Overall, no significant changes were noted between the 2 groups at 3 month or 1-year follow-up. Perioperatively, patients did report improvement in all outcome parameters within the PEEK and titanium groups. No significant difference was noted in subsidence rate between the 2 groups. Segmental lordosis significantly increased within the PEEK (+4.8 degrees; P<0.001) and titanium (+4.6 degrees; P=0.003) cage groups, however no difference was noted between groups. No significant difference was noted in fusion between the PEEK and titanium cage cohorts (92.6% vs. 86.2%; P=0.36). Overall, while PEEK and titanium cages exhibit unique biomaterial properties, our study shows that there were no significant differences with respect to patient-reported outcomes or radiographic outcomes between the 2 groups at the 1-year follow-up time point. Level III.

Delayed asymptomatic retroperitoneal dislodgement into the pouch of Douglas of a TLIF cage: A case report and review of the literature

Background: Intraoperative anteropulsion of a transforaminal lumbar interbody fusion (TLIF) cage is infrequent but may have disastrous complications. Here, we present an 80-year-old female whose L5-S1 TLIF cage extruded anteriorly and later migrated into the pouch of Douglas (i.e. an anterior peritoneal reflection between the uterus and the rectum) posing potential significant risks/complications, particularly of a major vessel injury. Notably, this 80-year-old patient with degenerative lumbosacral scoliosis should have only undergone a lumbar decompression alone.Case Description: An 80-year-old female underwent a two-level L4-L5 and L5-S1 TLIF to address lumbosacral canal stenosis with degenerative scoliosis. During the L5-S1 TLIF, intraoperative fluoroscopy showed the anterior displacement of the cage ventral to the sacrum. As she remained hemodynamically stable, the cage was left in place. The postoperative CT scan confirmed that the cage was located in the retroperitoneum but did not jeopardize the major vascular structures. Three months later, however, the cage migrated inferiorly into the pouch of Douglas. Although asymptomatic, general surgery and gynecology advised laparoscopic removal of the cage to avoid the potential for a major vessel/bowel perforation. However, the patient refused further surgery, and 3 years later remained asymptomatic.Conclusion: Anterior cage migration following TLIF has been rarely reported. In this case, an L5-S1 TLIF cage extruded anteriorly in an 80-year-old severely osteoporotic female and migrated 3 months later into the pouch of Douglas, posing the risk of a major vessel/bowel injury. Although surgical removal was recommended, the patient refused further surgery but remained asymptomatic 3 years later. Notably, the authors, in retrospect, recognized that choosing to perform a 2-level TLIF in an 80-year-old female reflected poor judgment.

Long-term radiographic outcomes of expandable versus static cages in transforaminal lumbar interbody fusion.

Potential advantages of using expandable versus static cages during transforaminal lumbar interbody fusion (TLIF) are not fully established. The authors aimed to compare the long-term radiographic outcomes of expandable versus static TLIF cages. A retrospective review of 1- and 2-level TLIFs over a 10-year period with expandable and static cages was performed at the University of California, San Francisco. Patients with posterior column osteotomy (PCO) were subdivided. Fusion assessment, cage subsidence, anterior and posterior disc height, foraminal dimensions, pelvic incidence (PI), segmental lordosis (SL), lumbar lordosis (LL), pelvic incidence-lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), sacral slope (SS), and sagittal vertical axis (SVA) were assessed. A consecutive series of 178 patients (with a total of 210 levels) who underwent TLIF using either static (148 levels) or expandable cages (62 levels) was reviewed. The mean patient age was 60.3 ± 11.5 years and 62.8 ± 14.1 years for the static and expandable cage groups, respectively. The mean follow-up was 42.9 ± 29.4 months for the static cage group and 27.6 ± 14.1 months for the expandable cage group. Within the 1-level TLIF group, the SL and PI-LL improved with statistical significance regardless of whether PCO was performed; however, the static group with PCOs also had statistically significant improvement in LL and SVA. The expandable cage with PCO subgroup had significant improvement in SL only. All of the foraminal parameters improved with statistical significance, regardless of the type of cages used; however, the expandable cage group had greater improvement in disc height restoration. The incidence of cage subsidence was higher in the expandable group (19.7% vs 5.4%, p = 0.0017). Within the expandable group, the unilateral facetectomy-only subgroup had a 5.6 times higher subsidence rate than the PCO subgroup (26.8% vs 4.8%, p = 0.04). Four expandable cages collapsed over time. Expandable TLIF cages may initially restore disc height better than static cages, but they also have higher rates of subsidence. Unilateral facetectomy alone may result in more subsidence with expandable cages than using bilateral PCO, potentially because of insufficient facet release. Although expandable cages may have more power to induce lordosis and restore disc height than static cages, subsidence and endplate violation may negate any significant gains compared to static cages.

Oblique insertion of a straight cage during single level TLIF procedure proves to be non-inferior in terms of restoring segmental lordosis

IntroductionWith increasing relevance of the postoperative spinopelvic alignment, achieving optimal restoration of segmental lordosis (SL) during transforaminal lumbar interbody fusion (TLIF) has become increasingly important. However, despite the easier insertion of the straight cage, its potential to restore SL is still considered inferior to the preferred insert-and-rotate technique with a banana-shaped cage. Research questionTo determine, if simple oblique insertion of a straight cage allows for an equally effective restoration of SL, but reduces risk for intraoperative cage subsidence requiring revision surgery. Material and methodsThe authors retrospectively identified 81 patients who underwent single-level TLIF between 11/2017-03/2020. 40 patients were included in the straight cage group, 41 patients in the banana cage group. The authors determined pre- and postoperative SL from plain lateral radiographs. Bone density was analyzed on computed tomographs using Hounsfield unit (HU) values. ResultsBoth cage types were equally effective in restoring SL. However, 7.3% in the banana cage group, but none in the straight cage group, had to undergo revision surgery due to intraoperative cage subsidence. This was related to reduced bone density with lower HU values. DiscussionWith an extended dorsal release, the straight cage may be equally effective in restoring SL. Since no repositioning is needed after oblique insertion, the straight cage might cause less intraoperative endplate violation. ConclusionProvided an adequate surgical technique, both cage types might be equally effective in restoring SL after one-level TLIF surgery. However, the straight cage might represent the safer alternative in patients with reduced bone quality.

Expandable cages increase the risk of intraoperative subsidence but do not improve perioperative outcomes in single level transforaminal lumbar interbody fusion

BACKGROUND CONTEXTExpandable cages (EXP) are being more frequently utilized in transforaminal lumbar interbody fusions (TLIF). EXP were designed to reduce complications related to neurological retraction, enable better lordosis restoration, and improve ease of insertion, particularly in the advent of minimally invasive surgical (MIS) techniques, however they are exponentially more expensive than the nonexpandable (NE) alternative. PURPOSETo investigate the clinical results of expandable cages in single level TLIF. STUDY DESIGN/SETTINGRetrospective review at a single institution. PATIENT SAMPLETwo hundred and fifty-two single level TLIFs from 2012 to 2018 were included. OUTCOME MEASURESClinical characteristics, perioperative and neurologic complication rates, and radiographic measures. METHODSPatients ≥18 years of age who underwent single level TLIF with minimum 1 year follow-up were included. Outcome measures: clinical characteristics, perioperative and neurologic complications. Radiographic analysis included pelvic incidence-lumbar lordosis (PI-LL) mismatch, segmental lumbar lordosis (LL) mismatch, disc height restoration, and subsidence ≥2 mm. Statistical analysis included independent t tests and chi-square analysis. For nonparametric variables, Mann-Whitney U test and Spearman partial correlation were utilized. Multivariate regression was performed to assess relationships between surgical variables and recorded outcomes. For univariate analysis significance was set at p<.05. Due to the multiple comparisons being made, significance for regressions was set at p<.025 utilizing Bonferroni correction. RESULTSTwo hundred and fifty-two TLIFs between 2012 and 2018 were included, with 152 NE (54.6% female, mean age 59.28±14.19, mean body mass index (BMI) 28.65±5.38, mean Charlson Comorbidity Index (CCI) 2.20±1.89) and 100 EXP (48% female, mean age 58.81±11.70, mean BMI 28.68±6.06, mean CCI 1.99±1.66) with no significant differences in demographics. Patients instrumented with EXP cages had a shorter length of stay (3.11±2.06 days EXP vs. 4.01±2.64 days NE; Z=-4.189, p<.001) and a lower estimated blood loss (201.31±189.41 mL EXP vs. 377.82±364.06 mL NE; Z=-6.449, p<.001). There were significantly more MIS-TLIF cases and bone morphogenic protein (BMP) use in the EXP group (88% MIS, p<.001 and 60% BMP, p<.001) as illustrated in Table 1. There were no significant differences between the EXP and NE groups in rates of radiculitis and neuropraxia. In multivariate regression analysis, EXP were not associated with a difference in perioperative outcomes or complications. Radiographic analyses demonstrated that the EXP group had a lower PI-LL mismatch than the NE cage group at baseline (3.75±13.81° EXP vs. 12.75±15.81° NE; p=.001) and at 1 year follow-up (3.81±12.84° EXP vs. 8.23±12.73° NE; p=.046), but change in regional and segmental alignment was not significantly different between groups. Multivariate regression demonstrated that EXP use was a risk factor for intraoperative subsidence (2.729[1.185–6.281]; p=.018). CONCLUSIONSOnce technique was controlled for, TLIFs utilizing EXP do not have significantly improved neurologic or radiographic outcomes compared with NE. EXP increase risk of intraoperative subsidence. These results question the value of the EXP given the higher cost.

P133. Does bone morphogenic protein (BMP) use reduce pseudoarthrosis rates in single-level TLIF surgeries?

BACKGROUND CONTEXT Recombinant human bone morphogenetic protein 2 (rhBMP-2) is a popular biologic product used in transforaminal lumbar interbody fusion (TLIF) surgeries to promote fusion and avoid the morbidity associated with iliac crest autograft. However, use of rhBMP-2 and its effect on pseudarthrosis rates in TLIFs remains unknown. PURPOSE To assess the rates of pseudarthrosis in open and MIS TLIF patients, with and without concurrent rhBMP-2 use. STUDY DESIGN/SETTING Retrospective cohort study at a single academic institution. PATIENT SAMPLE Included: 317 single level TLIF patients. Consisting of 157 open TLIF (OTLIF), 115 bilateral Wiltse MIS TLIF (WTLIF), and 45 hybrid midline MIS with percutaneous pedicle or cortical screws (MTLIF). OUTCOME MEASURES Clinical characteristics, perioperative and postoperative outcomes, surgical procedure, rates of pseudarthrosis diagnosis, and revision for pseudarthrosis. METHODS Patients ≥18 years old undergoing 1-level TLIF with minimum 1-year of clinical and radiographic follow up were included. Pseudarthrosis was determined using both radiographic and clinical evaluations. Differences between groups were assessed by ANOVA and chi squared analyses. Demographic and perioperative characteristics were analyzed by multivariate logistic regression. RESULTS The cohort included 317 patients (mean age 59.68±13.29, F 52.7%). There was no significant difference in gender, BMI, or smoking status among groups (all p>.05). WTLIF had the lowest EBL (ml) (192.16±177.11mL vs 302.73±246.51 vs 363.85±370.49, respectively p= CONCLUSIONS MP use did not reduce the rate of pseudarthrosis or the number of reoperations for pseudarthrosis in this cohort. No difference in pseudarthrosis rates between the three TLIF approaches was noted. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.