2-level Posterior Lumbar Interbody Fusion Research Articles

Effect of the administration route on the hemostatic efficacy of tranexamic acid in patients undergoing short-segment posterior lumbar interbody fusion: a systematic review and meta-analysis.

Tranexamic acid (TXA) is an FDA-approved antifibrinolytic that is seeing increased popularity in spine surgery owing to its ability to reduce intraoperative blood loss (IOBL) and allogeneic transfusion requirements. The present study aimed to summarize the current literature on these formulations in the context of short-segment instrumented lumbar fusion including ≥ 1-level posterior lumbar interbody fusion (PLIF). The PubMed, Cochrane, and Web of Science databases were queried for all full-text English studies evaluating the use of topical TXA (tTXA), systemic TXA (sTXA), or combined tTXA+sTXA in patients undergoing PLIF. The primary endpoints of interest were operative time, IOBL, and total blood loss (TBL); secondary endpoints included venous thromboembolic complication occurrence, and allogeneic and autologous transfusion requirements. Outcomes were compared using random effects. Comparisons were made between the following treatment groups: sTXA, tTXA, and sTXA+tTXA. Given that sTXA is arguably the standard of care in the literature (i.e., the most common route of administration that to this point has been studied the most), the authors compared sTXA versus tTXA and sTXA versus sTXA+tTXA. Study heterogeneity was assessed with the I2 test, and grouped analysis using the Hedge's g test was performed for measurement of effect size. Forty-five articles were identified, of which 17 met the criteria for inclusion with an aggregate of 1008 patients. TXA regimens included sTXA only, tTXA only, and various combinations of sTXA and tTXA. There were no significant differences in operative time, TBL, or postoperative drainage between the sTXA and tTXA groups or between the sTXA and sTXA+tTXA groups. The present meta-analysis suggested clinical equipoise between isolated sTXA, isolated tTXA, and combinatorial tTXA+sTXA formulations as hemostatic adjuvants/neoadjuvants in short-segment fusion including ≥ 1-level PLIF. Given the theoretically lower venous thromboembolism risk associated with tTXA, additional investigations using large cohorts comparing these two formulations within the posterior fusion population are merited. Although TXA has been shown to be effective, there are insufficient data to support topical or systemic administration as superior within the open PLIF population.

Ninety day adverse events following single level posterior lumbar interbody fusion in patients with sickle cell disease

Background ContextSickle cell disease (SCD) is an inherited disorder of red blood cells caused by mutation in the hemoglobin beta chain and is the most common inherited genetic disorder in the United States. Postoperative outcomes following single-level posterior lumbar interbody fusion (PLIF) in patients with SCD are not well characterized. PurposeTo examine 90-day postoperative outcomes among a matched cohort of patients with and without SCD who underwent single level PLIF utilizing a national administrative database. Study Design/SettingRetrospective database study. Patient SampleAdult patients without and with SCD who underwent single level PLIF from 2010 to 2021 Q1 were identified and matched 10:1 based on age, sex and ECI. Exclusion criteria included: age <18 years old, recent history of infection, neoplasm, or trauma, as well as not being active in the database for 90 days following their procedure. Outcome MeasuresNinety-day postoperative adverse events and emergency department (ED) visits. MethodsThe matched cohorts were defined, and 90-day adverse event and ED visit rates were compared with univariable analyses and multivariable logistic regression, controlling for age, sex, and Elixhauser comorbidity index (ECI). ResultsOverall, 191,765 PLIF patients were identified, of which SCD was noted for 76 (0.04%). On multivariable analysis of the matched populations, patients with SCD were at increased odds ratio (OR) of the following (in decreasing OR order): transfusion (OR 17.69), pneumonia (OR 6.30), sepsis (OR 4.86), aggregated minor adverse events (OR 4.65), aggregated all adverse events (OR 3.87), ED visits (OR 3.53), and aggregated severe adverse events (OR 2.80) (p<.05 for all). ConclusionsThe current study examined a relatively small, but largest to date, cohort of SCD patients undergoing PLIF. Patients with this condition were at greater odds of several perioperative adverse events, and these findings may be helpful for patient counselling and surgical planning.

Using Lordotic Cages at the L5-S1 Level Does Not Guarantee the Improvement of Sagittal Alignment in Patients Who Underwent Posterior Lumbar Interbody Fusion.

Retrospective comparative study. This study aimed to investigate the effects of the lordotic angle of cages on sagittal alignment in patients who underwent 1- or 2-level posterior lumbar interbody fusion (PLIF), including the L5-S1 level. Few studies have addressed the effects of the lordotic angle of cages on regional and global sagittal balance in patients undergoing PLIF at the L5-S1 level. Sixty-one patients who underwent 1- or 2-level PLIF, including the L5-S1 level, were divided into two groups based on the lordotic angle of cages (4° and 8° in 41 and 20 patients, respectively). Clinical and radiological parameters were compared. Correlation analyzes were performed to reveal the effect of flexibility and position of cages on the regional sagittal parameters. Pre- and postoperative clinical and radiological parameters were not different between the two groups. Although clinical outcomes improved postoperatively, sagittal parameters did not improve postoperatively in both groups. Patients who underwent 1-level PLIF at the L5-S1 level with the use of 8° cages showed no postoperative improvement (segmental angle: 16.1°-15.9°, p =0.140; lumbar lordosis: 44.8°-47.8°, p =0.740) of regional sagittal parameters. The degree of anterior location of cages showed a positive correlation with the postoperative restoration of the segmental angle (p =0.012 and p =0.050 at 1 and 2 years postoperatively, respectively). Clinical and radiological outcomes based on the lordotic angle of cages were not different. Even with the use of 8° cages and regardless of the more anterior position of cages, sagittal alignment did not improve in cases involving the L5-S1 level. PLIF at the L5-S1 level should be used with caution because improvement in sagittal alignment did not occur.

Negative versus natural drainage after single-level posterior lumbar interbody fusion. A prospective randomized study

IntroductionDespite of their extensive use, drains remain controversial without clear guidelines, and there is unclear evidence on drain use in spine procedures. Negative pressure drainage is theoretically more effective in preventing postoperative hematomas. On the contrary, it may result in excessive drainage and blood loss.The aim of this study was to compare the outcome between the uses of negative versus natural drainage in single level posterior lumbar interbody fusion (PLIF). Research questionThe aim is to compare between negative versus natural drainage after single-level PLIF as regard to postoperative wound infection, wound healing, temperature, pain and neurological deficits. Materials and methodsA prospective randomized study of consecutive PLIF patients at a single level for lumbar disc prolapse was performed between January 2019 and January 2020. The patients were randomly assigned to either the negative suction drainage group or natural drainage group. Negative suction was created by maximum compression of the reservoir to create negative pressure. In the other group, natural pressure drainage was kept without any negative pressure.Our study included a total of 62 patients who met the inclusion criteria. They were divided into two groups; 33 patients had negative suction drains and 29 patients had natural drainage. There were 32 female (51.6%) and 30 male (48.4%). Their ages ranged between of 23–69 years, with a mean age of 42.11 ​± ​8.89 years. ResultsDrainage volume was statistically higher in the negative group on the day of surgery (day 0) as well as the 1st and second days after. However, no significant differences were observed as regards to postoperative temperature, pain, wound infection, temperature, or neurological deficits. Discussion &conclusionIn this prospective randomized study, our results revealed that natural drainage in short term can reduce the total amount of blood in the drain, and therefore the blood loss without significant differences in postoperative wound infection, wound healing, temperature, pain, or neurological deficits in single-level PLIF.

Comparison of Fusion Rate and Functional Outcome Between Local Cancellous Bone Plus Demineralized Bone Matrix and Local Bone in 1-Level Posterior Lumbar Interbody Fusion.

Study Design:Retrospective study with prospectively collected data.Objective:The purpose of this study is to investigate the difference in fusion rate and clinical outcome of patients with local bone as filler for the graft and demineralized bone matrix (DBM) plus only the cancellous bone from local bone as a filler for cage in 1-level posterior lumbar interbody fusion (PLIF) with cage.Summary of Background Data:Cancellous bone is more advantageous than cortical bone in the local bone for improving bone formation in spine fusion surgery. There are little studies on the difference in fusion rate and reduction of fusion time using only these cancellous bones.Methods:Of the 40 patients who underwent 1-level PLIF using cage, 20 patients in group A used local bone and 20 patients in group B used mixture of cancellous bone extracted separately from local bone and commercially available DBM as filler for cage. Changes in fusion rate and intervertebral spacing were measured using lateral radiography, and fusion was determined as nonunion using the Brantigan-Steffee classification. The clinical outcome was evaluated.Results:There was no difference in height change over time between the two groups. Regarding union grade, group B showed better union grade than group A. However, no difference in union grade change over time was observed between the 2 groups. In group B, Oswestry Disability Index (ODI), Rolland-Morris Disability Questionnaire (RMDQ), and SF-36 mental component score (MCS) significantly decreased, but there was no difference in change over time.Conclusions:In 1-level PLIF for degenerative lumbar disease, better fusion rate was observed in the group that used only cancellous bone from local bone plus DBM than that in the group that used local bone; however, there was no difference in fusion grade change over time in the 2 groups.

Negative impact of short-level posterior lumbar interbody fusion in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segment.

The development of diffuse idiopathic skeletal hyperostosis (DISH) often requires further surgery after posterior decompression without fusion because of postoperative intervertebral instability. However, there is no information on whether fusion surgery is recommended for these patients as the standard surgery. The aim of this study was to review the clinical and imaging findings in lumbar spinal canal stenosis (LSS) patients with DISH affecting the lumbar segment (L-DISH) and to assess the indication for fusion surgery in patients with DISH. A total of 237 patients with LSS underwent 1- or 2-level posterior lumbar interbody fusion (PLIF) at the authors' hospital and had a minimum follow-up period of 2 years. Patients with L-DISH were classified as such (n = 27, 11.4%), whereas those without were classified as controls (non-L-DISH; n = 210, 88.6%). The success rates of short-level PLIF were compared in patients with and those without L-DISH. The rates of adjacent segment disease (ASD), pseudarthrosis, postoperative symptoms, and revision surgery were examined in the two groups. L-DISH from L2 to L4 correlated significantly with early-onset ASD, pseudarthrosis, and the appearance of postsurgical symptoms, especially at a lower segment and one distance from the segment adjacent to L-DISH, which were associated with the worst clinical outcome. Significantly higher percentages of L-DISH patients developed ASD and pseudarthrosis than those in the non-L-DISH group (40.7% vs 4.8% and 29.6% vs 2.4%, respectively). Of those patients with ASD and/or pseudarthrosis, 69.2% were symptomatic and 11.1% underwent revision surgery. The results highlighted the negative impact of short-level PLIF surgery for patients with L-DISH. Increased mechanical stress below the fused segment was considered the reason for the poor clinical outcome.

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

BackgroundAlthough the original technique involves inserting two cages bilaterally, there could be situations that only allow for insertion of one cage unilaterally. However, only a few studies have compared the outcomes between unilateral and bilateral cage insertion. The purpose of this study was to compare the clinical and radiological outcomes in patients who underwent posterior lumbar interbody fusion (PLIF) between unilaterally and bilaterally inserted cages.MethodsAmong 206 eligible patients who underwent 1- or 2-level PLIF, 78 patients were 1:3 cohort-matched by age, sex, and operation level (group U, 19 patients with unilateral cages; and group B, 57 patients with bilateral cages). Fusion status was evaluated by computed tomography (CT) scans at postoperative 1 year. Clinical outcomes were measured by visual analog scale (VAS), Oswestry Disability Index (ODI), and EQ-5D. Radiological and clinical parameters were compared between the two groups. Risk factors for pseudarthrosis were also analyzed by multivariate analysis.ResultsThe demographic data were not significantly different between the two groups. However, previous laminectomy, asymmetric disc collapse, and fusion at L5-S1 level were more frequently found in group U (P = 0.003, P = 0.014, and P = 0.014, respectively). Furthermore, pseudarthrosis was more frequently observed in group U (36.8%) than in group B (7.0%) (P = 0.004). Back pain VAS was higher in group U at postoperative 1 year (P = 0.033). Lower general activity function of EQ-5D was observed in group U at postoperative 1 year (P = 0.035). Older age (P = 0.028), unilateral cage (P = 0.007), and higher bone mineral density (P = 0.033) were positively correlated with pseudarthrosis.ConclusionsUnilaterally inserted cage might be a possible risk factor for pseudarthrosis when performing PLIF, which could be related with the difficult working conditions such as scars due to previous laminectomy or asymmetric disc collapse. Furthermore, suboptimal clinical outcomes are expected following PLIF with unilateral cage insertion at postoperative 1 year regardless of similar clinical outcomes at postoperative 2 year. Therefore, caution is advised when inserting cages unilaterally, especially under above-mentioned conditions in terms of its possible relationship with symptomatic pseudarthrosis.

Comparison of Short-Term Radiographical and Clinical Outcomes After Posterior Lumbar Interbody Fusion With a 3D Porous Titanium Alloy Cage and a Titanium-Coated PEEK Cage.

Study Design:Clinical case series.Objectives:To compare the short-term (≤1 year) radiographical and clinical outcomes between posterior lumbar interbody fusion (PLIF) with a titanium-coated poly-ether-ether-ketone (TCP) cage and PLIF with a three-dimensional porous titanium alloy (PTA) cage.Methods:Overall, 63 patients who had undergone 1- or 2-level PLIF since March 2015 were enrolled (median age, 71 years). The first 34 patients underwent PLIF with TCP cages (until June 2017) and the next 29 patients with PTA cages. Fusion status, vertebral endplate cyst formation (cyst sign: grade 0, none; grade 1, focal; and grade 2, diffuse), cage subsidence (grade 0, <1 mm; grade 1, 1–3 mm; and grade 2, >3 mm), and patient-reported quality of life (QOL) outcomes based on the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) were compared at 6 months and 1 year postoperatively between the 2 cage groups.Results:Cyst sign and cage subsidence grades were significantly lower in the PTA cage group than in the TCP cage group at 6 months postoperatively (cyst sign, p = 0.044; cage subsidence, p = 0.043). In contrast, the fusion rate and surgery effectiveness based on JOABPEQ at both 6 months and 1 year postoperatively were not different between the 2 groups.Conclusions:Patient-reported QOL outcomes were similar between the TCP and PTA cage groups until 1 year postoperatively. However, a higher incidence and severity of postoperative vertebral endplate cyst formation in patients with the TCP cage was a noteworthy radiographical finding.

Impact of Early Intervertebral Osseous Union After Posterior Lumbar Interbody Fusion on Health-Related Quality of Life.

Study Design:Retrospective cohort study.Objectives:Nonunion after posterior lumbar interbody fusion (PLIF) is associated with poor improvements in health-related quality of life (HRQOL). We aimed to investigate the influence of early osseous union after PLIF on HRQOL.Methods:We reviewed 138 patients with 1-level PLIF (mean age 67 years, follow-up period ≥1 year). Postoperative lumbar computed tomography was performed to assess screw loosening and intervertebral union. HRQOL was assessed using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire.Results:Thirty-nine patients (28%) showed complete union at 6 months postoperatively (early union group). Twenty-eight patients (20%) showed complete union at 6 to 12 months postoperatively (delayed union group), while 71 patients demonstrated noncomplete union. Effective improvement of lumbar spine dysfunction and psychological disorders was achieved in 19 (63.3%) and 17 (50.0%) patients in the early union group, in 9 (42.9%) and 14 (53.8%) patients in the delayed union group, and in 22 (34.9%) and 19 (29.2%) patients in the nonunion group, respectively (P = .036 and P = .036, respectively). The nonunion group had a significantly higher proportion of cases with screw loosening at 6 and 12 months postoperatively than the complete union group (P = .033 and P = .022).Conclusions:Lumbar spine dysfunction and psychological disorders improved in cases with early complete union compared to those with nonunion. Screw loosening occurred in cases with nonunion predominantly from 6 months postoperatively. Therefore, the achievement of early complete union might be helpful for better HRQOL and lower incidence of postoperative complications.

Efficacy of interspinous device on adjacent segment degeneration after single level posterior lumbar interbody fusion: a minimum 2-year follow-up

Objective Adjacent segment degeneration (ASD) is a well-known problem of posterior lumbar interbody fusion (PLIF). A device for interspinous assisted motion (DIAM) has been recently applied at the adjacent segment to pedicle screw instrumentation to create a dynamic transition zone. The aim of this study was to determine whether DIAM implantation at the adjacent segment could reduce the occurrence of radiologic and symptomatic ASD. Methods This retrospective study reviewed 51 patients who underwent PLIF with or without DIAM between 2005 and 2016. They were followed up for more than 24 months. The mean follow-up was over 5 years. Fourteen patients underwent PLIF with DIAM implantation at the cephalad level (Group A) and 37 patients received PLIF only (Group B). In radiologic ASD, several parameters were measured using pre- and post-operative radiographs and magnetic resonance image for lumbar degenerative disease and paraspinal muscle. Visual analogue scale (VAS) and Roland-Morris Disability Questionnaire (RMDQ) scores of back and leg were used to investigate symptomatic ASD. Results In postoperative radiographic changes, disc height narrowing and progression of spondylolisthesis at adjacent segment were significantly less in group A than those in group B (0.58 mm versus 1.17 mm, p = 0.038 and 0.30 mm versus 1.69 mm, p = 0.041, respectively). In clinical assessments, back VAS and RMDQ scores improved significantly more in group A (−4.07 versus −2.54, p = 0.029 and −7.57 versus −5.43, p = 0.016, respectively). Conclusion DIAM implantation with single-level PLIF could prevent disc height narrowing and progression of spondylolisthesis at adjacent segment. Clinically, DIAM implantation reduced back pain and disability. Therefore, DIAM implantation could help slow the progression of both radiologic and symptomatic ASD.

Impact of sufficient contact between the autograft and endplate soon after surgery to prevent nonunion at 12 months following posterior lumbar interbody fusion.

Nonunion after posterior lumbar interbody fusion (PLIF) is associated with poor long-term outcomes in terms of health-related quality of life. Biomechanical factors in the fusion segment may influence spinal fusion rates. There are no reports on the relationship between intervertebral union and the absorption of autografts or vertebral endplates. Therefore, the purpose of this retrospective study was to evaluate the risk factors of nonunion after PLIF and identify preventive measures. The authors analyzed 138 patients who underwent 1-level PLIF between 2016 and 2018 (75 males, 63 females; mean age 67 years; minimum follow-up period 12 months). Lumbar CT images obtained soon after the surgery and at 6 and 12 months of follow-up were examined for the mean total occupancy rate of the autograft, presence of a translucent zone between the autograft and endplate (more than 50% of vertebral diameter), cage subsidence, and screw loosening. Complete intervertebral union was defined as the presence of both upper and lower complete fusion in the center cage regions on coronal and sagittal CT slices at 12 months postoperatively. Patients were classified into either union or nonunion groups. Complete union after PLIF was observed in 62 patients (45%), while nonunion was observed in 76 patients (55%). The mean total occupancy rate of the autograft immediately after the surgery was higher in the union group than in the nonunion group (59% vs 53%; p = 0.046). At 12 months postoperatively, the total occupancy rate of the autograft had decreased by 5.4% in the union group and by 11.9% in the nonunion group (p = 0.020). A translucent zone between the autograft and endplate immediately after the surgery was observed in 14 and 38 patients (23% and 50%) in the union and nonunion groups, respectively (p = 0.001). The nonunion group had a significantly higher proportion of cases with cage subsidence and screw loosening at 12 months postoperatively in comparison to the union group (p = 0.010 and p = 0.009, respectively). A lower occupancy rate of the autograft and the presence of a translucent zone between the autograft and endplate immediately after the surgery were associated with nonunion at 12 months after PLIF. It may be important to achieve sufficient contact between the autograft and endplate intraoperatively for osseous union enhancement and to avoid excessive absorption of the autograft. The achievement of complete intervertebral union may decrease the incidence of cage subsidence or screw loosening.

Two-level Posterior Lumbar Interbody Fusion at the Lumbosacral Segment has a High Risk of Pseudarthrosis and Poor Clinical Outcomes

This was a retrospective study. The purposes of this study were to investigate the fusion rate and clinical outcomes of 2-level posterior lumbar interbody fusion (PLIF). PLIF provides favorable clinical outcomes and a high fusion rate. However, most extant studies have been limited to the results of single-level PLIF. Clinical outcomes and fusion rate of 2-level PLIF are unknown. In total, 73 patients who underwent 2-level PLIF below L3 between 2008 and 2016 (follow-up period >2 y) were included. Patients were divided into the 2 groups on the basis of surgical level. The lumbar group included 48 patients who underwent L3/4/5 PLIF, and the lumbosacral group included 25 patients who underwent L4/5/S PLIF. Fusion rate and clinical outcomes were compared. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and a visual analog scale were used for evaluation. Fusion rate was significantly lower in the lumbosacral group (lumbar 96% vs. lumbosacral 64%; P<0.001). Eight of 9 cases of pseudarthrosis occurred at the lumbosacral segment. Improvement in the mental health domain of the JOAPEQ was significantly lower in the lumbosacral group (lumbar 16 vs. lumbosacral 10; P=0.02). The VAS data showed that improvements in the following variables were significantly lower in the lumbosacral group than in the lumbar group: pain in low back (lumbar -38 vs. lumbosacral -23; P=0.004), pain in buttocks or lower leg (lumbar -48 vs. lumbosacral -29; P=0.04), and numbness in buttocks or lower leg (lumbar -44 vs. lumbosacral -33; P=0.04). Two-level PLIF at the lumbosacral segment demonstrated a significantly lower fusion rate and poorer clinical outcomes than that at the lumbar-only segments. Some reinforcement for the sacral anchor is recommended to improve fusion rate, even for short fusion like 2-level PLIF, if the lumbosacral segment is included. Level III.

Lordosis Recreation With PLIF Surgery-What Is the Influence on Adjacent Segment Lordosis?: An Observational Study of Radiological Alignment Change.

Retrospective cohort. We aimed to assess the changes in adjacent segmental lordosis (SL) across the intervertebral disc space following single level posterior lumbar interbody fusion (PLIF). Adjacent segment degeneration is well documented following fusion surgery as are the spinopelvic parameters. What isn't known is the effect of fusion surgery on the adjacent SL of the lumbar spine following PLIF. Preoperative and 1-year postoperative erect lateral radiographs were analyzed for lordotic angulation of all lumbar segments and pelvic incidence (PI) in patients undergoing L4/5 or L5/S1 PLIF. Fourty seven PLIFs achieved a mean of 7° increase in SL at L4/5 (P < 0.05) and 11° at L5/S1 (P < 0.05). In L5/S1 PLIF the lordosis gain was associated with lordosis reduction at adjacent segments 3° at L4/5 (P < 0.05); 1° at L3/4 (P < 0.05), 0° at L2/3(NS); 0° at L1/2(NS), and modest gain in overall lordosis (3°). At L4/5 PLIF the global lordosis increased by 5°, but less so at the adjacent discs (L5/S1 = 1°; L3/4 ≤ 1°; L2/3 ≤ -1°, and; L1/2 = <-1°). 19% of cases had a PI-LL > 10° preoperatively, reducing to 4° postoperatively. SL increased significantly at the PLIF level. At L5/S1 minimal overall lordosis change occurred however there was reduction in lordosis at adjacent levels representing reduced adjacent segment "compensation." Conversely L4/5 PLIF showed minimal change at adjacent levels but greater overall lordosis increase. Lumbar lordosis (LL) assessment requires monosegmental assessment as well as overall measure of the LL. PLIF surgery changes both LL and SL at adjacent levels. 3.

A Long-Term Follow-up, Multicenter, Comparative Study of the Radiologic, and Clinical Results Between a CaO-SiO2-P2O5-B2O3 Bioactive Glass Ceramics (BGS-7) Intervertebral Spacer and Titanium Cage in 1-Level Posterior Lumbar Interbody Fusion

This is a prospective, stratified randomized, multicenter, 4-year follow-up study. The authors aimed to evaluate the long-term clinical efficacy and safety of CaO-SiO2-P2O5-B2O3 glass ceramics (BGS-7) spacers in 1-level posterior lumbar interbody fusion (PLIF) at a 4-year follow-up. According to 1-year follow-up results, BGS-7 spacer showed similar fusion rates and clinical outcomes compared with titanium cage. A long-term follow-up study beyond 2 years is necessary to investigate the status of intervertebral bone graft volumes. Moreover, longer follow-up is mandatory to also evaluate the safety and efficacy of BGS-7 spacers, because they remain in the intervertebral space for a long time. In this prospective, randomized, multicenter, 4-year follow-up study, we evaluated 62 of the 74 patients who underwent 1-level PLIF. During 1-level PLIF, titanium cages filled with autologous local bone were inserted into the control group patients and BGS-7 spacers were inserted to the experimental group patients. Bone fusion was evaluated by plain radiography and thin-section computed tomography. Visual Analog Scale (VAS), the Oswestry Disability Index (ODI), Short Form-36 Health Survey (SF-36), and evaluation of safety were conducted after 48 months. Computed tomography scan showed a bone fusion rate of 90.6% in the BGS-7 spacer group and 93.3% in the control group, with no significant differences between groups. The BGS-7 spacer group showed a significantly larger area directly fused to the endplate than the control group (P<0.001). The BGS-7 spacer group showed a significant increase in the fused area compared with the titanium group at 1- and 4-year follow-up. The ODI, SF-36, back pain, and lower limb pain in both groups showed significant improvement after surgery, and no significant differences were observed between the groups. Both groups showed no additional adverse events. The 4-year follow-up study showed similar fusion rates and clinical outcomes in both the BGS-7 spacer and autologous bone with a titanium cage in 1-level PLIF. However, the BGS-7 spacer implants showed a larger area of fusion with the endplates than that of autologous bone with a titanium cage. Therefore, the results demonstrated that the BGS-7 spacer can be considered as a novel intervertebral spacer to achieve successful spinal fusion without safety concerns for long-term use.

P64. Initiation of a standardized escalation pain protocol after 1-2 level lumbar fusion reduces in-hospital opioid consumption

BACKGROUND CONTEXT Our previous study showed that prescribing patterns, more than surgery invasiveness or patient factors, affect post-operative opioid consumption. Since then we have instituted a Standard Escalation Pain Protocol (SEPP): patients receive 0-60 Morphine Milligram Equivalents (MME) above their baseline pre-op MME after surgery. PURPOSE The purpose of this study is to evaluate how prescribing patterns affect immediate postoperative opioid consumption in patients undergoing 1- to 2-level posterior lumbar interbody fusion with a navigated or robotic-assisted, midline exposure (MIDLIF). STUDY DESIGN/SETTING Single surgeon consecutive series. PATIENT SAMPLE Patients with degenerative lumbar pathology who had a MIDLIF from 2017 to 2018 were identified. OUTCOME MEASURES In-hospital opioid consumption. METHODS Patients with degenerative lumbar pathology who had a MIDLIF from 2017 to 2018 were identified and divided into two cohorts: patients who had surgery before the institution of SEPP (PreSEPP) and those who had surgery after (PostSEPP). Length of stay and daily opioid consumption were extracted by EMR data analysts unaware of the purpose of the study. RESULTS The PreSEPP (N=34) and PostSEPP (N=27) patients were similar at baseline in age, sex distribution, ASA grade, BMI and smoking status. Pre-Op (2.2 vs 3.6, p=0.630) and Post-op Day-0 (POD-0, 52.5 vs 38.8, p=0.192) MME consumption was similar between the two groups. At POD-1, cumulative MME consumption was higher in the Pre-SEPP (131.7) compared to the PostSEPP group (76.0, p=0.004) and this was maintained up to discharge (54% total MME reduction). Length of stay was also longer in the PreSEPP (1.97 days) compared to the PostSEPP group (1.37 days, p=0.004). CONCLUSIONS The use of a standard escalation pain protocol decreases in-hospital opioid consumption by 54% and shortens length of stay after 1-2 level lumbar spinal fusion. Similar to our previous study, prescribing pattern is an important factor affecting post-op opioid consumption. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Does Prophylactic Administration of TXA Reduce Mean Operative Time and Postoperative Blood Loss in Posterior Approach Lumbar Spinal Fusion Surgery Performed for Degenerative Spinal Disease?

This is a level III retrospective cohort study. To investigate association between prophylactic tranexamic acid (TXA) administration before 1 and 2-level posterior lumbar interbody fusion operations and perioperative blood loss (including intraoperative blood loss and postoperative drain output), mean operative time, postoperative transfusion, and postoperative venous thromboembolic events. TXA is a systemic antifibrinolytic that competitively inhibits lysine binding sites on plasminogen, reversibly blocking its binding to fibrin and impeding fibrinolysis and clot degradation. TXA's role in routine spinal surgery remains poorly described. Most spinal literature on perioperative TXA administration has considered operations performed for major adult and pediatric spinal deformity. Two groups, a study group composed of 75 patients who underwent 1 and 2-level posterior lumbar interbody fusion operations for degenerative indications who received TXA before the start of the procedure, and a control group composed of 75 patients who underwent similar surgeries for the same indications and did not receive TXA preoperatively, were retrospectively enrolled. Demographic, laboratory, and surgical data were collected and analyzed. No statistically significant differences were found between groups with respect to surgery type, home anticoagulation, postoperative anticoagulation, preoperative hemoglobin and hematocrit, estimated intraoperative blood loss, postoperative day 2 drain output, postoperative day 3 drain output, rate of postoperative transfusion, and rate of postoperative thromboembolic events. Statistically significant reductions were noted in the TXA group with regards to postoperative day 1 drain output (P<0.0041), total postoperative drain output (P=0.027), and mean surgical time (P<0.0001). In the present study, perioperative TXA administration was associated with reduced postoperative drain output and surgical time. Further higher-level studies are required to investigate the safety and utility of TXA's routine use in 1 and 2-level posterior lumbar fusion operations performed for degenerative indications.

Effect of segmental lordosis on the clinical outcomes of 2-level posterior lumbar interbody fusion for 2-level degenerative lumbar spondylolisthesis.

Although the importance of spinopelvic sagittal balance and its implications for clinical outcomes of spinal fusion surgery have been described, to the authors' knowledge there have been no reports of the relationship between spinopelvic alignment and clinical outcomes for 2-level posterior lumbar interbody fusion (PLIF). The purpose of this study was to elucidate the relationship between clinical outcomes and spinopelvic sagittal parameters after 2-level PLIF for 2-level degenerative spondylolisthesis (DS). This study was limited to patients who were treated with 2-level PLIF for 2-level DS at L3-4-5. Between 2005 and 2014, 33 patients who could be followed up for at least 2 years were included in this study. The average age at the time of surgery was 72 years, and the average follow-up period was 5.6 years. Based on clinical assessments, the Japanese Orthopaedic Association (JOA) score and recovery rate were evaluated. The patients were divided into 2 groups based on the recovery rate: the good outcome group (G group; n = 19), with recovery rate ≥ 50%, and the poor outcome group (P group; n = 14) with recovery rate < 50%. Spinopelvic parameters were measured using lateral standing radiographs of the whole spine as follows: sagittal vertical axis (SVA), thoracic kyphosis (TK), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), and segmental lordosis (SL) at L3-4-5. The clinical outcomes and radiological parameters were assessed preoperatively and at the final follow-up. Radiological parameters were compared between the 2 groups. The mean JOA score improved significantly in all patients from 10.8 points before surgery to 19.6 points at the latest follow-up (mean recovery rate 47.7%). For radiological outcomes, no difference was observed from preoperative assessment to final follow-up in any of the spinopelvic parameters except SVA. Although no significant difference between the 2 groups was detected in any of the spinopelvic parameters, there were significant differences in the change in SL and LL (ΔSL 3.7° vs -2.1° and ΔLL 1.2° vs -5.6° for the G and P groups, respectively). In addition, the number of patients in the G group was significantly larger for the patients with ΔSL-plus than those with ΔSL-minus (p = 0.008). The clinical outcomes of 2-level PLIF for 2-level DS limited at L3-4-5 appeared to be satisfactory. The results indicate that acquisition of increased SL in surgery might lead to better clinical outcomes.

Patient Blood Management During Lumbar Spinal Fusion Surgery

Patient blood management (PBM) is defined as treatment of a patient who is at risk of transfusion to minimize the need for transfusion and improve the probability of an optimal clinical outcome. We performed the present study to examine the effects of PBM in spinal fusion surgery. A total of 154 patients who had undergone 1- and 2-level posterior lumbar interbody fusion for degenerative lumbar disease were included. We retrospectively reviewed the data from 101 patients from 2012 to 2016 as the pre-PBM group. We recruited 53 patients from 2017 to 2018 for the post-PBM group. Intravenous iron was administered 2-4 weeks before surgery, and intravenous tranexamic acid was administered intraoperatively in the post-PBM group. The primary outcome was the reduction of hemoglobin (Hb). The secondary outcomes included perioperative blood loss, Hemovac drain output, postoperative transfusion, complications, and length of hospital stay. Intravenous iron was administered 17.4 days before surgery in the post-PBM group. The reduction in Hb was not significantly different statistically between the 2 groups (3.06 vs. 3.33 g/dL; P > 0.05). Of the 101 patients in the pre-PBM group, 24 (24%) underwent transfusion. In contrast, no patient in the post-PBM group had required a transfusion (P < 0.001). The average hospital stay was 10.15 days in the pre-PBM group and 8.33 days in the post-PBM group (P= 0.02). The average operative time was 146 minutes in the pre-PBM group and 133 minutes in the post-PBM group (P= 0.03). The Hb decrease and total Hemovac drain output did not differ significantly between the 2groups. Implementation of PBM is an effective strategy for reducing the rate of transfusion in patients undergoing lumbar spinal fusion surgery without significant complications.

Multiple-Repeated Adjacent Segment Disease After Posterior Lumbar Interbody Fusion

Although posterior lumbar interbody fusion (PLIF) has provided satisfactory clinical outcomes, adjacent segment disease (ASD) is one of the most important complications affecting long-term results. However, according to ASD studies, few have described repeat surgery. The purpose of this study was to elucidate incidence, time period, and clinical features of multiple-repeated ASD after PLIF. Subjects comprised 1112 consecutive patients (502 men, 610 women) who underwent 1-level PLIF for degenerative lumbar diseases. The mean age of patients was 66 years (range, 15-89). The mean follow-up period was 6.4 years (range, 0.5-21.1). The incidence and the time period of multiple-repeated ASD were investigated. To elucidate clinical features of the multiple-repeated ASD, all 4 cases were shown as the case description including radiographic parameters. Four (0.4%) developed multiple-repeated ASD: 3 women and 1 man. Primary PLIF was performed at L3-4 in 1 patient and at L4-5 in 3 patients. Two patients underwent adjacent segment decompression simultaneously. All patients required at least 3 additional surgeries due to newly occurred ASD after each PLIF. All patients developed iatrogenic flatback as ASD was repeated. As a result, corrective surgeries were required (thoracolumbar, 2; spinopelvic, 2). Multiple-repeated ASD was observed in 0.4% of the patients. All patients developed iatrogenic flatback as a result of repeated ASD, and corrective surgeries were required for these patients.

Computed tomography color mapping for evaluation of bone ongrowth on the surface of a titanium-coated polyetheretherketone cage in vivo

Bone ongrowth on the surfaces of titanium (Ti)-coated polyetheretherketone (PEEK) materials has been demonstrated in animal models; however, whether this occurs on the surfaces of Ti-coated PEEK cages in lumbar interbody fusion has not been demonstrated clinically in vivo. This prospective observational study was aimed to develop and validate a computed tomography (CT) color mapping based on Hounsfield unit (HU) values for evaluation of bone ongrowth on the surfaces of the Ti-coated PEEK cage after posterior lumbar interbody fusion (PLIF).Twenty-four consecutive patients (11 men and 13 women; mean age, 67.0 years; range, 20–82 years) who underwent single- or 2-level PLIF since March 2015 were included. Two Ti-coated PEEK cages were inserted in all PLIF segments. From reconstructed sagittal planes from postoperative CT scans (within 1 week and 6 months postoperatively), bone ongrowth on the surfaces of cage frames was evaluated by CT color mapping. Inter- and intraobserver reliability of the assessment of bone ongrowth by CT color mapping was evaluated by Cohen's kappa coefficient. The relation between CT color mapping and HU values on the surfaces of cage frames was also analyzed.A total of 248 surfaces of cage frames were evaluated. Bone ongrowth was observed in 134 of 248 surfaces (54.0%) by CT color mapping. Intraobserver reliability for the evaluation of bone ongrowth was kappa = 0.831, and interobserver reliability was kappa = 0.713. The HU values in the local regions of interest (ROIs) on the surfaces of cage frames where the postoperative bone ongrowth existed on CT color mapping increased significantly postoperatively (P < .001), and the median postoperative change rate of the HU values in the local ROIs was 22.4%.The assessment of bone ongrowth on the surfaces of Ti-coated PEEK cages by CT color mapping had adequate inter- and intraobserver reliability, which was useful especially in detecting local increase in HU values on the surfaces of the cages. This method is an easy and visually comprehensible method for the assessment of bone ongrowth in the bone-implant interface.