Two-level Posterior Lumbar Interbody Fusion Research Articles

Accuracy and Screw Insertion Time of Robotic-Assisted Cortical Bone Trajectory Screw Placement for Posterior Lumbar Interbody Fusion: A Comparison of Early, Middle, and Late Phases.

Introduction The purpose of this study was toevaluate robotic-assisted cortical bone trajectory (CBT) screw placement. Early, middle, and late phases of robotic-assisted CBT screw placement were compared for accuracy and screw insertion time by comparing time and accuracy in every phase. Methods A retrospective review was conducted on the initial 40 patients who underwent spinal fusion using CBT screws in one institution from September 2021 to September 2022 utilizing a spine surgery robot system (Mazor X Stealth Edition, Medtronic Inc., Dublin, Ireland). The inclusion criterion was one- or two-level posterior lumbar interbody fusion (PLIF). Exclusion criteria were 1) patients who underwent posterior-lateral fusion in other segments, 2) patients who underwent additional decompression in other segments, 3) patients who underwent reoperation, and 4) patients with spondylolysis. The deviation of the CBT screw was evaluated on computed tomography (CT) one week after surgery using the Gertzbein-Robbins grade system. The rate of Grade A was considered the perfect accuracy rate, and the rate of penetration of 2 mm or more (Grades C, D, and E) was calculated as the deviation rate. To assess the learning curve, patients were divided into three groups. The first 10 cases were in the early phase group, the subsequent 10 cases were in the middle phase group, and the last 10 cases were in the late phase group. We compared the perfect accuracy rate, deviation rate, operative time, operative time per segment, intraoperative blood loss, registration time, and screw insertion time among the three groups. Results Thirty patients met the criteria. Overall, the perfect accuracy (Grade A) rate of the screw was 95.3% and the deviation rate was 1.4%. The perfect accuracy rate was 90.4% in the early phase, 95.5% in the middle phase, and 100% in the late phase. The deviation rate was 3.8% in the early phase, 0% in the middle phase, and 0% in the late phase, and there was no statistically significant difference between the three groups. Among the three groups, the operative time, the operative time per segment, the intraoperative blood loss, and the registration time were not significantly different. There was no significant difference in the screw insertion time among the three groups, but it decreased with experience (early phase: 156.9 ± 54.7 sec, middle phase: 139.9 ± 41.6 sec, and late phase: 106.4 ± 39.9 sec, p=0.060). The screw insertion time of the late phase tended to be shorter than that of the early phase (p=0.052). Conclusions The deviation rate of robotic-assisted CBT screw placement with one- or two-level PLIF was 1.4%, which was highly accurate. The deviation rate was 3.8% in the early phase, 0% in the middle phase, and 0% in the late phase. Although the deviation rate was low even in the early period, the screw insertion time in the early 10 cases tended to be longer than that in the late 10 cases. After passing the experience of 10 cases, this study concluded that robotic-assisted CBT screw placement was proficient.

Comparison of Opioid Consumption Patterns of Three Interbody Fusion Surgical Techniques.

Retrospective review. With increased awareness of the opioid crisis in spine surgery, the focus postoperatively has shifted to managing surgical site pain while minimizing opioid use. Numerous studies have compared outcomes and fusion status of different interbody fusion techniques; however, there is limited literature evaluating opioid consumption postoperatively between techniques. The aim of this study was to assess in-house and postoperative opioid consumption across 3 surgical techniques. Patients were stratified by technique: posterior lumbar interbody fusion (PLIF), minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), and cortical screw (CS) instrumentation with interbody fusion. Age, ASA, BMI, depression, preoperative opioid use, EBL, and OR time were recorded and compared across surgical groups using Welch's ANOVA and chi-square analysis. Total morphine equivalent dose (MED) was tabulated for both in-house consumption and postoperative prescriptions and was compared across surgical techniques using Welch's ANOVA analysis, Mann Whitney U tests, and linear regression. Two hundred and thirty nine patients underwent one- or two-level posterior lumbar interbody fusion between 2016 and 2020. One hundred and twenty one patients underwent CS instrumentation, 95 underwent PLIF, and 83 underwent MIS-TLIF. There was a significantly higher percentage of patients who had a history of depression and preoperative opioid consumption in the CS group (P = .001, P = .009). CS instrumentation required significantly less total post-op opioids per kilogram bodyweight compared to MIS-TLIF and PLIF surgeries (P = .029). Patients who underwent CS instrumentation required less opioids postoperatively. CS instrumentation may be associated with less postoperative pain due to the less invasive approach, however, patient education and prescriber practice also play a role in postoperative opioid consumption.

151. Comparison of opioid consumption patterns of three interbody fusion surgical techniques

<h3>BACKGROUND CONTEXT</h3> Back pain and spine surgery have been major drivers of opioid consumption and spine surgery has been linked to the opioid epidemic. With increased awareness of the opioid crisis, the focus postoperatively has shifted to managing surgical site pain while minimizing narcotic use. Numerous studies have compared clinical outcomes and fusion status of different lumbar interbody fusion techniques; however, there is limited literature evaluating narcotic consumption postoperatively between techniques. The aim of this study was to assess and compare in-house and postoperative opioid consumption among three surgical techniques. <h3>PURPOSE</h3> To examine posterior lumbar fusion surgical techniques and compare opioid consumption across the techniques. <h3>STUDY DESIGN/SETTING</h3> Retrospective review. <h3>PATIENT SAMPLE</h3> Three hundred and three patients who underwent one- or two-level posterior lumbar interbody fusion surgery. <h3>OUTCOME MEASURES</h3> Primary outcome measure was opioid consumption across surgical techniques both while in-patient and after discharge as determined by total morphine equivalent dose (MED). Secondary outcomes included operative time, length of stay, and discharge destination. <h3>Methods</h3> This is a retrospective review of patients who underwent one- or two-level posterior lumbar interbody fusion surgery at a single institution between 2016 and 2020. Patients were stratified by surgical technique: posterior lumbar interbody fusion (PLIF), minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), and cortical screw (CS) instrumentation with interbody fusion. Age, ASA, BMI, depression, preoperative opioid use, EBL and OR time were recorded and compared across surgical groups using one-way ANOVA and chi-square analysis. Total morphine equivalent dose (MED) was tabulated for both in-house consumption and postoperative prescriptions and was compared across surgical techniques using ANOVA analysis. <h3>Results</h3> A total of 303 patients underwent one- or two-level posterior lumbar interbody fusion between 2016 and 2020. 123 patients underwent cortical screw instrumentation, 96 underwent PLIF and 84 underwent MIS-TLIF. There was a significantly higher percentage of patients who had a history of depression and were on preoperative opioids in the CS group (p=0.001, p=0.002). Patients with CS instrumentation required significantly less narcotics per day while in-house compared to PLIF and MIS-TLIF (MED 80.65 vs 97.85 vs 83.72, p = 0.030). Patients who underwent CS instrumentation received half the number of narcotics compared to PLIF patients after discharge (MED 956.15 vs 2260.89, p = 0.003). <h3>Conclusions</h3> Patients who underwent CS instrumentation required less narcotics postoperatively both while admitted and after discharge. CS instrumentation may be associated with less postoperative pain due to the less invasive approach, however, patient education and prescriber practice also play a role in postoperative narcotic consumption. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P64. Impact of body mass index on opioid consumption in lumbar spine fusion surgery

<h3>BACKGROUND CONTEXT</h3> The prevalence of obesity continues to rise in the United States. The CDC published that from 1999-2000 through 2017-2018 the prevalence of obesity increased from 30.5% to 42.4% and the prevalence of severe obesity nearly doubled. In lumbar spine surgery, obesity is associated with increased complications, worse perioperative outcomes, and higher costs. Obesity is also linked to depression and anxiety, which have both been shown to increase the use of opioids. We hypothesize that patients who are obese require more opioids postoperatively. <h3>PURPOSE</h3> To examine the association between body mass index (BMI) and opioid consumption in patients undergoing lumbar spine fusion surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review. <h3>PATIENT SAMPLE</h3> Three hundred and six patients who underwent one- or two-level posterior lumbar interbody fusion surgery. <h3>OUTCOME MEASURES</h3> Primary outcome measure was opioid consumption across obesity classes both while in-patient and after discharge as determined by total morphine equivalent dose (MED). Secondary outcomes included operative time, length of stay, and discharge destination. <h3>METHODS</h3> This is a retrospective review of patients who underwent one- or two-level posterior lumbar interbody fusion surgery between 2016 and 2020. Patients were stratified by BMI as follows: normal weight (18.5-24.9 kg/m2), overweight (25.0–29.9 kg/m2), obese I (30.0–34.9 kg/m2), and obese II–III (≥ 35.0 kg/m2). Patient demographics and preoperative characteristics were compared across the BMI cohorts using one-way ANOVA and chi-square analysis. <h3>RESULTS</h3> Three hundred and six patients were included in the analysis, of whom 19.3% (N=59) were normal weight, 38.9% (N=119) were overweight, 24.5% (N=75) were obese I, and 17.3% (N=53) were obese II-III. Obesity is associated with significantly longer operative times and length of stay (p<0.001, p = 0.19). There is no difference in in-house opioid consumption across groups (p = 0.207). Severely obese patients (Class II-III) are prescribed more than double the number of postoperative opioids (p = 0.001). <h3>CONCLUSIONS</h3> This study illustrates that obesity is associated with longer operative times, longer length of stay, and increased use of postoperative opioids. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P65. Marijuana use is associated with increased use of prescription opioids following posterior lumbar spine fusion surgery

<h3>BACKGROUND CONTEXT</h3> Marijuana is an antinociceptive which has been evaluated as a possible adjunct or substitute for opioid use in the treatment of acute pain. The aim of this study was to evaluate the association between preoperative marijuana usage and consumption of opioids for postoperative analgesia. We hypothesized that marijuana usage may be associated with decreased usage of opioid analgesics in postoperative pain relief in patients undergoing spine surgery. <h3>PURPOSE</h3> To examine the association between marijuana use and opioid consumption in patients undergoing lumbar spine fusion surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review. <h3>PATIENT SAMPLE</h3> Two hundred and twenty-one patients who underwent one- or two-level posterior lumbar interbody fusion surgery. <h3>OUTCOME MEASURES</h3> Primary outcome measures were opioid consumption in marijuana users and non- marijuana users both while in-patient and after discharge as determined by total morphine equivalent dose (MED). Secondary outcome measures included operative time, length of stay, discharge destination, and readmission rates. <h3>METHODS</h3> Retrospective review of 221 patients who underwent one- or two-level posterior lumbar fusion surgery between 2016 and 2020 at a single institution. Patients were categorized as marijuana users or non-marjiuana users based on preoperative diagnoses of marijuana use. Total morphine equivalent dose (MED) was calculated for both in-house opioid consumption and postoperative prescription opioid usage. Patients who were on opioids preoperatively were excluded. Patient demographics and preoperative characteristics were compared across the BMI cohorts using one-way ANOVA and chi-square analysis. <h3>RESULTS</h3> Of 221 total patients, 29 patients were identified as marijuana users while 192 were non- marijuana users. There were no significant associations between marijuana usage and age, ASA, BMI, tobacco use, EBL, OR time, LOS, or disposition to rehab. Marijuana users had greater association with depression (31% vs 12.5%, p=0.032) and 30-day readmission (17.2% vs 11.5% (p<0.001). Marijuana users were found to have increased opioid consumption in-house (MED 236.49 vs 166.68, p=0.005), as well as increased postoperative prescription opioid usage (2415.62 vs 1391.54, p=0.007). <h3>CONCLUSIONS</h3> Marijuana usage is associated with increased usage of opioids postoperatively, both while in patient and post-discharge, after posterior lumbar spine fusion surgery. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

204. A clinical pilot study showing the safety and efficacy of intramuscular injection of atelocollagen for prevention of paraspinal muscle atrophy after spine surgery

<h3>BACKGROUND CONTEXT</h3> Atelocollagen has been widely used as an intradermal filler to restore soft tissue defects. Many studies demonstrated that atelocollagen provides good therapeutic results by promoting cell proliferation and enhances the healing effect on injured muscles and connective tissues such as tendons and fasciae while causing few complications. <h3>PURPOSE</h3> This clinical study was designed to assess the safety and efficacy of intramuscular injection of atelocollagen for the prevention of paraspinal muscle atrophy after spine surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective observational study. <h3>PATIENT SAMPLE</h3> A total of 118 patients who underwent single- or two-level posterior lumbar interbody fusion (PILF) between December 2017 and April 2019 were retrospectively reviewed. <h3>OUTCOME MEASURES</h3> Clinical efficacy was evaluated by the improvement of back pain, elevation of a muscle enzyme, and inflammatory markers. Radiologic efficacy was evaluated with a comparison of density and cross-sectional area (CSA) of multifidus and erector spinae muscle in CT images. The safety was assessed with vital sign monitoring and a survey on all adverse events over 12 weeks. <h3>METHODS</h3> In the study group of 30 patients, 3mL of gel-type 3% atelocollagen solution was prepared and injected into the multifidus muscle during wound closure. <h3>RESULTS</h3> Significant improvement of back pain was observed in all patients after the surgery. VAS for back pain was not significantly lower in the study group postoperatively compared with the control group. The reduction of postoperative paraspinal muscle density and CSA was significantly lower in the study group. The serum level of muscle enzyme and inflammatory markers were significantly lower in the study group. No major procedure-related complications were observed during the follow-up period. <h3>CONCLUSIONS</h3> Intramuscular injection of atelocollagen is safe and feasible for the prevention of paraspinal muscle atrophy after spine surgery. This novel method seems advantageous for accelerating wound healing without causing inflammation. Randomized controlled trials with larger data samples are needed to confirm the results. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Impact of body mass index on opioid consumption in lumbar spine fusion surgery

Backgroundin the United States from 1999 to 2000 through 2017–2018, the prevalence of obesity increased from 30.5 to 42.4%, while the prevalence of severe obesity nearly doubled. In lumbar spine surgery, obesity is associated with increased complications, worse perioperative outcomes, and higher costs. The purpose of this study was to examine the association between body mass index (BMI) and opioid consumption in patients undergoing lumbar spine fusion surgery. We hypothesized that obese patients would require more opioids postoperatively. Methodsretrospective review of 306 patients who underwent one- or two-level posterior lumbar interbody fusion surgery between 2016 and 2020. Patients were stratified by BMI as follows: normal weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2), obese I (30.0–34.9 kg/m2), and obese II–III (≥ 35.0 kg/m2). Patient demographics and preoperative characteristics were compared across BMI cohorts using one-way ANOVA and chi-square analysis. Patients with prior history of opioid use were excluded. Primary outcome measure was postoperative opioid consumption. Secondary outcomes included operative time, length of stay (LOS), discharge destination, and 30-day re-encounter rates. Outcomes were analyzed using multivariable linear regression adjusted for potential confounders. Resultsof 306 total patients, 17.3% were normal weight, 39.9% were overweight, 25.5% were obese I, and 17.3% were obese II–III. Obesity was associated with longer operative times and length of stay (p < 0.001, p = 0.024). For opioid naïve patients, there was no difference in-house opioid consumption when adjusted for kilograms of body mass and LOS (p = 0.083). Classes II–III patients were prescribed more than twice the number of postoperative opioids (p < 0.001) and were on opioids for a longer time postoperatively (p = 0.019). Conclusionobesity is associated with longer operative times, longer LOS, and increased consumption of postoperative opioids. This should be considered when counseling patients preoperatively prior to lumbar spine fusion procedures.

Impact of mechanical stability on the progress of bone ongrowth on the frame surfaces of a titanium-coated PEEK cage and a 3D porous titanium alloy cage: in vivo analysis using CT color mapping.

To determine the impact of mechanical stability on the progress of bone ongrowth on the frame surfaces of a titanium-coated polyether ether ketone (TCP) cage and a three-dimensional porous titanium alloy (PTA) cage following posterior lumbar interbody fusion (PLIF) until 1year postoperatively. A total of 59 patients who underwent one- or two-level PLIF for degenerative lumbar disorders since March 2015 were enrolled. Bone ongrowth of all cage frame surfaces (four surfaces per cage: TCP, 288 surfaces and PTA, 284 surfaces) was graded by 6-month and 1-year postoperative computed tomography color mapping (grade 0, 0‒25% of bone ongrowth; grade 1, 26‒50%; grade 2, 51‒75%; and grade 3, 76‒100%). Bone ongrowth (≥ grade 1) was observed on 58.0% and 69.0% of the surfaces of TCP and PTA cages 6months postoperatively and on 63.5% and 75.0% of those 1year postoperatively, respectively. In the TCP cages, bone ongrowth grade increased from 6months to 1year postoperatively only in the union segments (median, 1 [interquartile range, IQR, 0-2] to 1 [IQR, 0-3], p = 0.006). By contrast, in the PTA cages, it increased at 6months postoperatively in the union (1 [IQR, 1-2] to 2 [IQR, 1-3], p = 0.003) and non-union (0.5 [IQR, 0-2] to 1 [IQR, 0-2.75], p = 0.002) segments. Early postoperative mechanical stability has a positive impact on the progress of bone ongrowth on both the TCP and PTA cage frame surfaces after PLIF.

218. Preoperative opioid use is associated with increased readmission and reoperation rates following lumbar decompression, instrumentation and fusion

BACKGROUND CONTEXT The prescription opioid epidemic and widespread use of narcotic medications has introduced new challenges when treating patients undergoing spine surgery. Recent studies in general surgery, spine and total joint arthroplasty literature demonstrate associations between preoperative opioid use and increased emergency department visits, readmission rates, revision rates and risk of developing chronic opioid dependence. Researchers estimate that 33-70% of patients undergoing spinal surgery use opioids preoperatively. Given the prevalence of preoperative opioid consumption among patients undergoing spine surgery, further research is needed to quantify and stratify perioperative risks in this patient population. PURPOSE The purpose of this study is to compare outcomes of primary one- or two-level lumbar decompression, instrumentation and fusion based on preoperative opioid consumption habits. STUDY DESIGN/SETTING A retrospective chart review was performed on patients who underwent one- to two-level posterior lumbar decompression, instrumentation and fusion from two spine surgeons at a single, tertiary referral center from 2013-2017. PATIENT SAMPLE Inclusion criteria included all patients who underwent a primary one- to two-level decompression (laminectomy or laminotomy) with posterior instrumentation, one- or two-level intertransverse arthrodesis (PLF), one- or two-level transforaminal lumbar interbody fusion (TLIF) or one- or two-level posterior lumbar interbody fusion (PLIF). Exclusion criteria included patients undergoing revision surgery, patients with concomitant malignancy or surgery for neoplastic disease, three- or more-level surgery, anterior or lateral (direct or oblique) interbody fusions, traumatic injuries (acute fractures or ligamentous instability) or other concurrent procedures. Patient opioid use was obtained from electronic medical records (Epic Systems Corporation, Verona, WI) including medication history and preoperative clinical documentation. Patients were divided into chronic opioid therapy (COT; >6 months), acute users (0-6 months) and opiate-naive based on their preoperative opioid usage. OUTCOME MEASURES Primary endpoints included readmission rates within 1 year and reoperation rates within 2 years. METHODS A retrospective chart review was conducted from 2013-2017 and patients who met the inclusion criteria were studied. Patients were divided into three groups based on their aforementioned preoperative opioid consumption status. Demographic information (age, BMI, sex and ethnicity), smoking status and primary outcome measures were identified and recorded based on documentation in the electronic medical record. RESULTS A total of 93 patients met the inclusion and exclusion criteria (57 PLF, 31 TLIF and 5 PLIF). Demographics characteristics were similar between all three groups. Thirty-three patients (35.5%) required COT, 31 patients (33.3%) utilized acute opioid therapy and 29 patients (31.2%) remained opioid naive. Current or former smokers were more likely to utilize acute or COT than never smokers (86% vs 59%; p=0.005). Readmission rates within 1 year for patients in the COT, acute and opioid naive groups were 50%, 41.7% and 8.3%, respectively (p=0.0115). Reoperation rates within 2 years for patients in the COT, acute and opioid naive groups were 54.2%, 33.3% and 12.5%, respectively (p = 0.033). CONCLUSIONS Long-term opiate use is associated with an increased risk for readmission within 1 year and revision within 2 years following a primary posterior decompression, instrumentation and fusion. Numerous data base studies have demonstrated similar, suboptimal outcomes for patients on preoperative opioid therapy compared to nonusers. This retrospective chart review corroborates the findings of these previous studies. Given the prevalence of narcotic usage in the US population, physicians should continue to educate acute or chronic opioid users about increased risk of readmission and revision associated with lumbar decompression and fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

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.

Fusion Rate and Clinical Outcomes in Two-Level Posterior Lumbar Interbody Fusion.

Posterior lumbar interbody fusion (PLIF) has become a general surgical method for degenerative lumbar diseases. Although many reports have focused on single-level PLIF, few have focused on 2-level PLIF, and no report has covered the fusion status of 2-level PLIF. The purpose of this study is to investigate clinical outcomes and fusion for 2-level PLIF by using a combination of dynamic radiographs and multiplanar-reconstruction computed tomography scans. This study consisted of 48 consecutive patients who underwent 2-level PLIF for degenerative lumbar diseases. We assessed surgery duration, estimated blood loss, complications, clinical outcomes as measured by the Japanese Orthopaedic Association score, lumbar sagittal alignment as measured on standing lateral radiographs, and fusion status as measured by dynamic radiographs and multiplanar-reconstruction computed tomography. Patients were examined at a follow-up point of 4.8 ± 2.2 years after surgery. Thirty-eight patients who did not undergo lumbosacral fusion comprised the lumbolumbar group, and 10 patients who underwent lumbosacral fusion comprised the lumbosacral group. The mean Japanese Orthopaedic Association score improved from 12.1 to 22.4 points by the final follow-up examination. Sagittal alignment also was improved. All patients had fusion in the cranial level. Seven patients had nonunion in the caudal level, and the lumbosacral group (40%) had a significantly poorer fusion rate than the lumbolumbar group (97%) did. Surgical outcomes of 2-level PLIF were satisfactory. The fusion rate at both levels was 85%. All nonunion was observed at the caudal level and concentrated at L5-S level in L4-5-S PLIF.

Effect of one- or two-level posterior lumbar interbody fusion on global sagittal balance

Background ContextSagittal imbalance is associated with poor clinical outcomes in patients with degenerative lumbar disease. However, there is no consensus on the impact of posterior lumbar interbody fusion (PLIF) on local and global sagittal balance. PurposeTo reveal the effect of one- or two-level PLIF on global sagittal balance. Design/SettingA retrospective case-control study. Patients SampleThis study included 88 patients who underwent a one- or two-level PLIF for spinal stenosis with spondylolisthesis. Outcome MeasuresClinical and radiological parameters were measured pre- and postoperatively. MethodsAll patients were followed up for >2 years. Clinical outcomes included a visual analog scale, Oswestry Disability Index, and EuroQol 5-dimension questionnaire (EQ-5D). Radiological parameters were measured using whole-spine standing lateral radiographs. Fusion, loosening, subsidence rates, and adverse events were also evaluated. Patients were divided into two groups according to their preoperative C7–S1 sagittal vertical axis (SVA): Group N: SVA≤5 cm vs Group I: SVA>5 cm; they were also divided according to postoperative changes in C7–S1 SVA. Clinical and radiological outcomes were compared between the groups. ResultsAll clinical outcomes and radiological parameters improved postoperatively. C7–S1 SVA improved (−1.6 cm) after L3–L5 fusion, but it was compromised (+3.6 cm) after L4–S1 fusion (p=.001). Preoperative demographic and clinical data showed no difference except in the anxiety or depression domain of EQ-5D. No differences were found in postoperative clinical outcomes. Lumbar lordosis, pelvic tilt, and thoracic kyphosis slightly improved in Group N, whereas C7–S1 SVA decreased from 9.5 cm to 3.8 cm (p<.001) in Group I. Furthermore, all sagittal parameters improved in Group I. On comparing the postoperative changes in C7–S1 SVA, we found that the decreasing trend in the postoperative C7–S1 SVA was related to a larger preoperative C7–S1 SVA (p=.030) and a more proximal level fusion (L3–L5 vs L4–S1, p=.033). ConclusionsGlobal sagittal balance improved after short-level lumbar fusion surgery in patients having spinal stenosis with spondylolisthesis who showed preoperative sagittal imbalance. Restoration of sagittal balance predominantly occurred after L3–L4, L4–L5, or L3–L5 PLIF. However, no such restoration was observed after L5–S1 or L4–S1 PLIF. Thus, we could anticipate sagittal balance restoration after performing PLIF at L3–L4 or L4–L5 level. However, caution is required when planning for L5–S1 fusion if preoperative sagittal imbalance is present.

One and two level posterior lumbar interbody fusion (PLIF) using an expandable, stand-alone, interbody fusion device: a VariLift® case series.

Surgical interventions such as posterior lumbar interbody fusion (PLIF) with and without posterior instrumentation are often employed in patients with degenerative spinal conditions that fail to respond to conservative medical management. The VariLift® Interbody Fusion System was developed as a stand-alone solution to provide the benefits of an intervertebral fusion device without the requirement of supplemental pedicle screw fixation. In this retrospective case series, 25 patients underwent PLIF with a stand-alone VariLift® expandable interbody fusion device without adjunctive pedicle screw fixation. There were 12 men and 13 women, with a mean age of 57.2 years (range, 33-83 years); single level in 18 patients, 2 levels in 7 patients. Back pain severity was reported as none, mild, moderate, severe and worst imaginable at baseline, 6 and 12 months. Preoperatively, 88% (22 of 25) of patients reported severe back pain. All patients experienced symptomatic improvement and, by 12 months postoperatively, 71% (15 of 21) of patients reported only mild residual pain. Overall, pain scores improved significantly from baseline to 12 months (P=0.0002). There were no revision surgeries and fusion was achieved 12 of 13 patients (92%) who returned for a 12-month radiographic follow-up. There were three cases of intractable postsurgical pain which required extended hospitalization or pain management, one wound infection and one case of surgical site dehiscence, both treated and resolved during inpatient hospitalization. In this single-physician case series, the VariLift® device used in single or two-level PLIF provided effective symptom relief and produced a high fusion rate without the need for supplemental fixation.

The maturation of grafted bone after posterior lumbar interbody fusion with an interbody carbon cage

We evaluated the maturation of grafted bone in cases of successful fusion after a one- or two-level posterior lumbar interbody fusion (PLIF) using interbody carbon cages. We carried out a five-year prospective longitudinal radiological evaluation of patients using plain radiographs and CT scans. One year after surgery, 117 patients with an early successful fusion were selected for inclusion in the study. Radiological evaluation of interbody bone fusion was graded on a 4-point scale. The mean grades of all radiological and CT assessments increased in the five years after surgery, and differences compared to the previous time interval were statistically significant for three or four years after surgery. Because the grafted bone continues to mature for three years after surgery, the success of a fusion should not be assessed until at least three years have elapsed. There were no significant differences in the longitudinal patterns of grafted bone maturity between iliac bone and local bone. However, iliac bone grafting may remodel faster than local bone.

Clinical Results of Posterior Lumbar Interbody Fusion Using Titanium Intervertebral Spacers in Elderly Patients over 70 Years

Study Design : Retrospective study. Objective : To report the clinical and radiological results of posterior lumbar interbody fusion (PLIF) using titanium intervertebral spacers in elderly patients over 70 years. Summary of Background Data : PLIF with intervertebral spacers has been introduced to treat degenerative lumbar disorders. However, in the elderly patients, it is concerned that there are several possible complications that can be associated with the use of interbody support in anterior column reconstruction under weak bone quality. There were few reports about the results of PLIF using titanium intervertebral spacers in elderly patients. Methods : Twenty-six patients with mean age of 73 years (range, 70-78) underwent one or two-level PLIF using titanium intervertebral blocks combined with posterior instrumentation, with minimum 2-year follow-up (average 49 months ; range, 25-88). Radiographic and clinical outcomes analysis was performed. Results : The sagittal alignment (regional lordosis) of the operative segments averaged 7.4° before surgery, 12.7° at discharge, 11.1° post-op 1-year, and 11.8° at the final follow-up. The percentage of posterior disc height was 14.1% before surgery, and was significantly improved after the surgery to 26.9% at discharge and 21.8% at the final follow-up. In 18 patients with spondylolisthesis, the percentage of slip averaged 18.9% before surgery, and was significantly improved after the surgery to 6.8% at discharge and maintained until the final follow-up. All patients had radiographic fusion at the follow-up. The average JOA score was 12.6 points before surgery, and increased significantly to 23.1 points at the final follow-up. Conclusion : Posterior lumbar interbody fusion using titanium spacers is valuable even in the elderly patients. The preservation of bony endplate of vertebral body, and the insertion of spacers as antero-lateraly as possible in the intervertebral space, are important for successful fusion.

Dose-dependent inhibition of diclofenac sodium on posterior lumbar interbody fusion rates

Background context The use of nonsteroidal anti-inflammatory drugs (NSAIDs) had been implicated as a risk factor for nonunion in spinal fusion. Even with a number of animal and human studies suggesting NSAIDs either delay or inhibit spinal fusion rates, these drugs continue to be used because of demonstrated benefits. Diclofenac sodium is no exception. It is very popular as a first-line treatment for acute pain, even perioperatively for spine fusion patients. Review of published literature reveals no studies done on the effect of diclofenac sodium on spine fusion rates. Purpose To determine if diclofenac sodium is a risk factor for delayed union and nonunion in adult patients who underwent one- to two-level instrumented posterior lumbar interbody fusion (PLIF) using only local autogenous bone graft. Study design/setting Retrospective, analytical. Patient sample Two hundred and seventy-three adult patients who underwent one- to two-level PLIF with minimum 2-year follow-up. Outcome measures Diclofenac sodium intake, fusion status. Methods Medical records and radiographs of 273 adult patients who underwent one- to two-level PLIF in a single institution from 1999 to 2004 were reviewed. All patients did not use any NSAID or steroid perioperatively, except for diclofenac sodium postoperatively. The amount of diclofenac sodium used was quantified for the first 14 days post-op. These patients were followed-up periodically for 2 years. Demographic data, levels fused, and NSAID intake were correlated to union status. Results Nineteen out of the 273 patients had no diclofenac sodium intake (no-dose group), 168 patients used less than or equal to 300 mg (moderate-dose group), and 86 patients used more than 300 mg of diclofenac sodium (high-dose group). There were 4 nonunions and 41 delayed unions seen. No significant difference was seen when fusion status was compared with age, sex, L5–S1 versus other levels, and smoking history (all comparisons, p>.05). There was a significant difference between one- and two-level fusions in terms of union status (p=.002). There were no nonunions and 18 delayed unions seen in 217 patients in the single-level fusion group. All 4 nonunions and 23 delayed unions were noted among the 56 patients in the two-level group. There were no cases of delayed union and nonunion in the no-dose group. There were also no nonunions but 16 delayed unions in the moderate-dose group. There were 4 nonunions and 25 delayed unions in the high-dose group. As diclofenac sodium intake increases, the incidence of delayed union and nonunion were also seen to increase (p<.001). Time to union was correlated to the amount of diclofenac sodium intake using Pearson's correlation coefficient (r=0.271, p<.001). When the patients were divided into one- and two-level fusion groups, the amount of diclofenac sodium used still had a significant positive correlation to frequency of delayed union and nonunion and in time to union in each group (all comparisons, p<.05). Conclusions Diclofenac sodium showed a dose-dependent inhibitory effect toward spine fusion especially when used during the immediate postoperative period. No significant correlation was seen between age, sex, L5–S1 versus other levels fused and smoking history when compared with spine nonunion. Two-level lumbar fusions also showed a significant negative correlation to spine fusion compared with single-level fusions.

COMPARATIVE STUDY OF UNILATERAL AND BILATERAL CAGES WITH RESPECT TO CLINICAL OUTCOMES AND STABILITY IN INSTRUMENTED POSTERIOR LUMBAR INTERBODY FUSION

We sought to compare the clinical and radiological results of instrumented posterior lumbar interbody fusion (PLIF) using unilateral or bilateral polyetheretherketone cages and pedicle screws. One hundred eighty-seven cases of degenerative spine that had been followed for at least 18 months were reviewed retrospectively. In 88 cases (147 levels), one cage was inserted, and in 99 cases (152 levels), two cages were inserted. Visual analog scale, Oswestry disability index, and functional rating indices were measured. Lumbar lordosis, lumbar scoliotic and fusion level scoliotic angles, and stable fixation were determined before surgery and 12 months postoperatively on standing x-rays. Amounts of intra- and postoperative blood loss, total quantities transfused, and operation times were also evaluated. No significant differences were found between the two groups in terms of visual analog scale, Oswestry disability index, functional rating indices, lumbar lordosis, lumbar scoliotic angles, fusion level scoliotic angles, or fixation stabilities. However, the amounts of postoperative blood loss, total blood loss, and total transfusion for two-level PLIF using a unilateral cage were statistically smaller than those for two-level PLIF using bilateral cages. Times required for PLIF using a unilateral cage were also significantly shorter than those for PLIF using bilateral cages. Unilateral cage and bilateral pedicle screw insertion may be a good alternative surgical option because it provides adequate alignment, balance, and mechanical stability in addition to reducing operative time, blood loss, and transfusion requirements.

Two-level posterior lumbar interbody fusion for degenerative disc disease: improved clinical outcome with restoration of lumbar lordosis

Background context Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF. Purpose To evaluate the clinical outcomes of double-level PLIF. Study design/setting A retrospective study of operated cases in Gifu, Japan. Patient sample Nineteen patients (8 men and 11 women, 59.5±10.2 years) who underwent double-level PLIF between 1996 and 2001. Outcome measures Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated. Methods Patients were examined retrospectively at follow-ups of 3.6±1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases. Results The mean JOA score increased from an initial score of 12.9±3.5 to 21.3±4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal. Conclusion Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis.

Posterior spinal fusion for lumbar degenerative diseases using the Crock-Yamagishi (C-Y) spinal fixation system.

Although many transpedicular screw systems have been developed and have undergone wide clinical use, experience with semirigid transpedicular systems has rarely been reported. We evaluated the efficacy and safety of the Crock-Yamagishi (C-Y) system for posterior spinal fusion in lumbar degenerative diseases. The outcomes for 26 patients (14 men, 12 women) with lumbar degenerative diseases who underwent posterior spinal fusion using the C-Y system were analyzed (posterior lumbar interbody fusion (PLIF), 11 patients; posterolateral fusion (PLF), 14; and facet fusion (FF), 1. Symptoms were evaluated using the Japanese Orthopaedic Association Assessment of Treatment for Low Back Pain (JOA score). Preoperative scores ranged from -1 to 23 points (mean, 12.8), while postoperative scores ranged from 19 to 29 points (mean, 26.4). Degree of recovery ranged from 23.1% to 100% (mean, 83.2%). Overall fusion rate was 96.2% (25/26). Neither breakage nor loosening of implants was observed radiographically. Intra- and postoperative complications included one case of transient L5 nerve root palsy attributable to surgical technique, and one deep postoperative infection. The C-Y system, categorized as semirigid, is effective when used with one- or two-level PLIF or PLF for lumbar degenerative disorders, grade I to II spondylolisthesis, and failed back syndrome.