Surgical data and early postoperative outcomes after minimally invasive lumbar interbody fusion: results of a prospective, multicenter, observational data-monitored study

Anterolateral versus posterior minimally invasive lumbar interbody fusion surgery for spondylolisthesis: comparison of outcomes from a global, multicenter study at 12-months follow-up

BACKGROUND CONTEXT

Several minimally invasive lumbar interbody fusion techniques may be used as a treatment for spondylolisthesis to alleviate back and leg pain, improve function and provide stability to the spine. Surgeons may choose an anterolateral or posterior approach for the surgery however, there remains a lack of real-world evidence from comparative, prospective studies on effectiveness and safety with relatively large, geographically diverse samples and involving multiple surgical approaches.

PURPOSE

To test the hypothesis that anterolateral and posterior minimally invasive approaches are equally effective in treating patients with spondylolisthesis affecting one or two segments at 3-months follow-up and to report and compare patient reported outcomes and safety profiles between patients at 12-months post-surgery.

DESIGN

Prospective, multicenter, international, observational cohort study.

PATIENT SAMPLE

Patients with degenerative or isthmic spondylolisthesis who underwent 1- or 2-level minimally invasive lumbar interbody fusion.

OUTCOME MEASURES

Patient reported outcomes assessing disability (ODI), back pain (VAS), leg pain (VAS) and quality of life (EuroQol 5D-3L) at 4-weeks, 3-months and 12-months follow-up; adverse events up to 12-months; and fusion status at 12-months post-surgery using X-ray and/or CT-scan. The primary study outcome is improvement in ODI score at 3-months.

METHODS

Eligible patients from 26 sites across Europe, Latin America and Asia were consecutively enrolled. Surgeons with experience in minimally invasive lumbar interbody fusion procedures used, according to clinical judgement, either an anterolateral (ie, ALIF, DLIF, OLIF) or posterior (MIDLF, PLIF, TLIF) approach. Mean improvement in disability (ODI) was compared between groups using ANCOVA with baseline ODI score used as a covariate. Paired t-tests were used to examine change from baseline in PRO for both surgical approaches at each timepoint after surgery. A secondary ANCOVA using a propensity score as a covariate was used to test the robustness of conclusions drawn from the between group comparison.

RESULTS

Participants receiving an anterolateral approach (n=114) compared to those receiving a posterior approach (n=112) were younger (56.9 vs 62.0 years, p <.001), more likely to be employed (49.1% vs 25.0%, p<.001), have isthmic spondylolisthesis (38.6% vs 16.1%, p<.001) and less likely to only have central or lateral recess stenosis (44.9% vs 68.4%, p=.004). There were no statistically significant differences between the groups for gender, BMI, tobacco use, duration of conservative care, grade of spondylolisthesis, or the presence of stenosis. At 3-months follow-up there was no difference in the amount of improvement in ODI between the anterolateral and posterior groups (23.2 ± 21.3 vs 25.8 ± 19.5, p=.521). There were no clinically meaningful differences between the groups on mean improvement for back- and leg-pain, disability, or quality of life until the 12-months follow-up. Fusion rates of those assessed (n=158; 70% of the sample), were equivalent between groups (anterolateral, 72/88 [81.8%] fused vs posterior, 61/70 [87.1%] fused; p=.390).

CONCLUSIONS

Patients with degenerative lumbar disease and spondylolisthesis who underwent minimally invasive lumbar interbody fusion presented statistically significant and clinically meaningful improvements from baseline up to 12-months follow-up. There were no clinically relevant differences between patients operated on using an anterolateral or posterior approach.

Nonsteroidal anti-inflammatory drugs (NSAID) do not increase blood loss or the incidence of postoperative epidural hematomas when using minimally invasive fusion techniques in the degenerative lumbar spine

Objective

Nonsteroidal anti-inflammatory drugs (NSAID) are essential in surgeons' armamentarium for pain relief and antiphlogistic effects. However, spine surgeons are concerned about the drugs' impact on coagulation, fearing hemodynamic instability due to blood loss and neurological complications due to postoperative hematoma. Furthermore, there are no clear guidelines for the use of these drugs.

Materials and methods

In this retrospective subgroup analysis of a prospective observational study, we investigated 181 patients who underwent minimally invasive spinal fusions in degenerative lumbar spine pathologies. 83 patients were given NSAID perioperatively, 54 of which were female and 29 male. Of these patients who took NSAID, 39 were on NSAID until at least one day before surgery or perioperatively, whilst the others discontinued their NSAID medication at least three days before surgery. Differences in perioperative blood loss, as well as complication rates between patients with and without NSAID treatment, were investigated.

Results

A significantly higher amount of blood loss during surgery and the monitoring period was encountered in patients whose spine was fused in more than one level, regardless of whether NSAID medication was taken or not and up until what point. Furthermore, it was found that taking NSAID medication had no effect on the incidence of postoperative epidural hematomas.

Conclusion

Perioperatively taking NSAID medication does not increase blood loss or the incidence of postoperative hematoma in patients undergoing minimally invasive lumbar spinal fusion surgery.

Can artificial intelligence support or even replace physicians in measuring sagittal balance? A validation study on preoperative and postoperative full spine images of 170 patients

PURPOSE

Sagittal balance (SB) plays an important role in the surgical treatment of spinal disorders. The aim of this research study is to provide a detailed evaluation of a new, fully automated algorithm based on artificial intelligence (AI) for the determination of SB parameters on a large number of patients with and without instrumentation.

METHODS

Pre- and postoperative sagittal full body radiographs of 170 patients were measured by two human raters, twice by one rater and by the AI algorithm which determined: pelvic incidence, pelvic tilt, sacral slope, L1-S1 lordosis, T4-T12 thoracic kyphosis (TK) and the spino-sacral angle (SSA). To evaluate the agreement between human raters and AI, the mean error (95% confidence interval (CI)), standard deviation and an intra- and inter-rater reliability was conducted using intra-class correlation (ICC) coefficients.

RESULTS

ICC values for the assessment of the intra- (range: 0.88-0.97) and inter-rater (0.86-0.97) reliability of human raters are excellent. The algorithm is able to determine all parameters in 95% of all pre- and in 91% of all postoperative images with excellent ICC values (PreOP-range: 0.83-0.91, PostOP: 0.72-0.89). Mean errors are smallest for the SSA (PreOP: -0.1° (95%-CI: -0.9°-0.6°); PostOP: -0.5° (-1.4°-0.4°)) and largest for TK (7.0° (6.1°-7.8°); 7.1° (6.1°-8.1°)).

CONCLUSION

A new, fully automated algorithm that determines SB parameters has excellent reliability and agreement with human raters, particularly on preoperative full spine images. The presented solution will relieve physicians from time-consuming routine work of measuring SB parameters and allow the analysis of large databases efficiently.

Longitudinal Trends of Patient Demographics and Morbidity of Different Approaches in Lumbar Interbody Fusion: An Analysis Using the American College of Surgeons National Surgical Quality Improvement Program Database

OBJECTIVE

The aims of this study were to determine the time trend of demographics, complications, and outcomes for patients undergoing posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF) or anterior lumbar interbody fusion/lateral lumbar interbody fusion (ALIF/LLIF) and to compare the differences in the time trends between both procedures.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients undergoing PLIF/TLIF and ALIF/LLIF procedures. Outcomes were analyzed for differences between 2 time periods in the PLIF/TLIF and ALIF/LLIF cohorts separately (2009-2013 and 2015-2019). Longitudinal time trends of the 2 procedures were determined by difference-in-differences (DID) analysis. Statistical significance was defined as P < 0.05.

RESULTS

For both approaches, there was an increase in age and American Society of Anesthesiologists class over time, accompanied by a significant decrease in blood transfusions and morbidity. The DID analysis showed a greater change in age (DID:-1.8%; P < 0.001), and more patients were rated American Society of Anesthesiologists class 3 (DID: -2.4%; P = 0.033) in the ALIF/LLIF cohort than in the PLIF/TLIF cohort. Length of stay declined significantly over time in both cohorts, with a greater reduction observed for patients who underwent ALIF/LLIF than for patients who underwent PLIF/TLIF (DID: 0.2%; P = 0.014). There were no changes in readmission rates over time in either cohort (PLIF/TLIF DID: 0.6%; P = 0.080; ALIF/LLIF DID: -0.2%; P = 0.696).

CONCLUSIONS

Time trends for PLIF/TLIF and ALIF/LIIF showed a significant increase in the number of older patients with complex medical status undergoing surgery. Despite these trends, there were decreases in overall postoperative morbidity, incidence of blood transfusion, and length of stay, without increasing readmission. These results suggest general improvement in surgical and perioperative management of lumbar fusion over time with greater gains found in ALIF/LLIF-specific care than in PLIF/TLIF.

Accidental Dural Tears in Minimally Invasive Spinal Surgery for Degenerative Lumbar Spine Disease

Background: One of the most frequent complications of spinal surgery is accidental dural tears (ADTs). Minimal access surgical techniques (MAST) have been described as a promising approach to minimizing such complications. ADTs have been studied extensively in connection with open spinal surgery, but there is less literature on minimally invasive spinal surgery (MISS).

Materials and Methods: We reviewed 187 patients who had undergone degenerative lumbar spinal surgery using minimally invasive spinal fusions techniques. We analyzed the influence of age, Body Mass Index (BMI), smoking, diabetes, and previous surgery on the rate of ADTs in MISS.

Results: Twenty-two patients (11.764%) suffered from an ADT. We recommended bed rest for two and a half to 5 days, depending on the type of repair required and the amount of cerebrospinal fluid (CSF) leakage. We could not find any statistically significant correlation between ADTs and age (p = 0.34,), BMI (p = 0.92), smoking (p = 0.46), and diabetes (p = 0.71). ADTs were significantly more frequent in cases of previous surgery (p < 0.001). None of the patients developed a transcutaneous CSF leak or post-operative infection.

Conclusions: The frequency of ADTs in MISS appears comparable to that encountered when using open surgical techniques. Additionally, MAST produces less dead space along the corridor to the spine. Such reduced dead space may not be enough for pseudomeningocele to occur, cerebrospinal fluid to accumulate, and fistula to form. MAST, therefore, provides a certain amount of protection.

Are the Outcomes of Minimally Invasive Transforaminal/Posterior Lumbar Fusion Influenced by the Patient's Age or BMI?

STUDY DESIGN

A retrospective subgroup analysis of a prospective observational study was carried out.

SUMMARY OF BACKGROUND DATA

Patients' baseline characteristics may influence the clinical outcomes after minimally invasive lumbar interbody fusion (MILIF).

OBJECTIVE

This study aimed to investigate the influence of patient's age and body mass index (BMI) on the clinical outcomes of MILIF for degenerative lumbar disorder.

MATERIALS AND METHODS

A total of 252 patients underwent MILIF. The clinical outcomes, including time to first ambulation, time to postsurgical recovery, back/leg pain in visual analog scale, Oswestry Disability Index, and EuroQol-5 Dimension, were collected at baseline, 4 weeks, 6, and 12 months. Patients were subgrouped by age (50 y and below: N=102; 51-64 y: N=102; 65 y and above: N=48) and BMI (≤25.0: N=79; 25.1-29.9: N=104; ≥30.0: N=69). Data from baseline to 12 months were compared for all clinical outcomes within age/BMI subgroups. Adverse events (AEs) and serious adverse events (SAEs) were summarized by age and BMI subgroups.

RESULTS

All age and BMI subgroups showed significant improvements in clinical outcomes at 12 months compared with the baseline. The median time to first ambulation was similar for all subgroups (age groups: P=0.8707; BMI: P=0.1013); older people show a trend of having longer time to postsurgical recovery (age groups: P=0.0662; BMI: P=0.1591). Oswestry Disability Index, back, and leg pain visual analog scale, and EuroQol-5 Dimension were similar in all subgroups at every timepoint. A total of 50 AEs (N=39) were reported, 9 of which were SAEs; 3 AEs and 1 SAE were considered to be related to surgical procedure. No differences were observed in safety by age groups and BMI groups.

CONCLUSION

MILIF appears to be safe and effective, independent of age or weight in the treatment of degenerative lumbar disorder.

LEVEL OF EVIDENCE

Level II.

Approach-based Comparative and Predictor Analysis of 30-day Readmission, Reoperation, and Morbidity in Patients Undergoing Lumbar Interbody Fusion Using the ACS-NSQIP Dataset

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to determine the difference in 30-day readmission, reoperation, and morbidity for patients undergoing either posterior or anterior lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

Despite increasing utilization of lumbar interbody fusion to treat spinal pathology, few studies compare outcomes by surgical approach, particularly using large nationally represented cohorts.

METHODS

Patients who underwent lumbar interbody fusion were identified using the NSQIP database. Rates of readmission, reoperation, morbidity, and associated predictors were compared between posterior/transforaminal (PLIF/TLIF) and anterior/lateral (ALIF/LLIF) lumbar interbody fusion using multivariate regression. Bonferroni-adjusted alpha-levels were utilized whereby variables were significant if their P values were less than the alpha-level or trending if their P values were between 0.05 and the alpha-level.

RESULTS

We identified 26,336 patients. PLIF/TLIF had greater operative time (P = 0.015), transfusion (P < 0.001), UTI (P = 0.008), and stroke/CVA (P = 0.026), but lower prolonged ventilation (P < 0.001) and DVT (P = 0.002) rates than ALIF/LLIF. PLIF/TLIF independently predicted greater morbidity on multivariate analysis (odds ratio: 1.155, P = 0.0019).In both groups, experiencing a complication and, in PLIF/TLIF, ASA-class ≥3 predicted readmission (P < 0.001). Increased age trended toward readmission in ALIF/LLIF (P = 0.003); increased white cell count (P = 0.003), dyspnea (P = 0.030), and COPD (P = 0.005) trended in PLIF/TLIF. In both groups, increased hospital stay and wound/site-related complication predicted reoperation (P < 0.001). Adjunctive posterolateral fusion predicted reduced reoperation in ALIF/LLIF (P = 0.0018). ASA-class ≥3 (P = 0.016) and age (P = 0.021) trended toward reoperation in PLIF/TLIF and ALIF/LLIF, respectively. In both groups, age, hospital stay, reduced hematocrit, dyspnea, ASA-class ≥3, posterolateral fusion, and revision surgery and, in PLIF/TLIF, bleeding disorder predicted morbidity (P < 0.001). Female sex (P = 0.010), diabetes (P = 0.042), COPD (P = 0.011), and disseminated cancer (P = 0.032) trended toward morbidity in PLIF/TLIF; obesity trended in PLIF/TLIF (P = 0.0022) and ALIF/LLIF (P = 0.020).

CONCLUSION

PLIF/TLIF was associated with a 15.5% increased odds of morbidity; readmission and reoperation were similar between approaches. Older age, higher ASA-class, and specific comorbidities predicted poorer 30-day outcomes, while procedural-related factors predicted only morbidity. These findings can guide surgical approach given specific factors.

LEVEL OF EVIDENCE

3.

Surgical and Clinical Results of Minimally Invasive Spinal Fusion Surgery in an Unselected Patient Cohort of a Spinal Care Unit

OBJECTIVES

To review the surgical results and to identify possible parameters influencing the clinical outcomes in an unselected patient collective undergoing minimally invasive lumbar interbody fusion in a spinal care unit.

METHODS

A total of 229 adult patients who underwent minimally invasive lumbar spinal fusion between 2008 and 2016 were included in this retrospective analysis. Lumbar fusion was performed using transforaminal interbody fusion (TLIF) devices and posterolateral fusion. To eliminate confounding parameters, in all patients interbody fusion was indicated by lumbar degenerative pathologies, and surgery was performed using the same fusion device. Treatment efficacy was evaluated using scores describing pain (visual analogue scale [VAS]) and health impairment (EQ-5D, Oswestry Disability Index [ODI]). The influence of patient age, obesity, active smoking status, and co-morbidities on clinical outcome and perioperative complications was analyzed.

RESULTS

The patient population reviewed had improved VAS (P_{(leg pain)} ≤ 0.0001, P_{(back pain)} ≤ 0.0001), ODI (P ≤ 0.0001), EQ-VAS (P ≤ 0.0001), and EQ-5D subscales "mobility", "self-care", "pain", and "anxiety" (P_(mobility) ≤ 0.0001, P_(self-care)  = 0.41, P_(pain) ≤ 0.0001, P_(anxiety)  = 0.011) postoperatively. Neither advanced patient age, nor increased body mass index (BMI), hypertension, or active smoking status had a significantly limiting influence on the success of minimally invasive spinal surgeries (MIS). Duration of surgery strongly correlated with the number of spinal levels treated and with intraoperative blood loss (r = 0.774, P ≤ 0.0001, n = 208). Weak positive correlations were found between patient age and duration of surgery (r = 0.184, P = 0.005, n = 229), intraoperative blood loss (r = 0.165, P = 0.012, n = 229), and duration of hospitalization (r = 0.270, P ≤ 0.0001, n = 228), respectively. When compared to non-smokers, smokers were younger (P ≤ 0.0001), and had a significantly lower BMI (P = 0.001), shorter durations of surgery (P ≤ 0.0001), decreased intraoperative blood loss (P = 0.022), and shorter hospital stays (P = 0.006), respectively. Complications occurred in 17 patients (7%) and were not affected by patient age, BMI, hypertension, or active smoking status.

CONCLUSION

Minimally invasive spinal surgery is a safe and effective treatment option and may be superior to open surgery in subpopulations with significant co-morbidities and risk factors, such as elderly and obese patients as well as patients with an active smoking status.

Transforaminal Lumbar Interbody Fusion: Traditional Open Versus Minimally Invasive Techniques

Recently, minimally invasive spine arthrodesis has gained popularity among spine surgeons. Minimally invasive techniques have advantages and disadvantages compared with traditional open techniques. Comparisons between short-term outcomes of minimally invasive transforaminal interbody fusion and open transforaminal interbody fusion in terms of estimated blood loss, postoperative pain, and hospital length of stay have been well documented and generally favor the minimally invasive technique. However, the advantages of minimally invasive transforaminal interbody fusion must be evaluated in the context of long-term results, such as patient-reported outcomes and the success of arthrodesis. Because the literature is equivocal in identifying the superior technique for successful long-term outcomes, more study is needed. Patient safety, the risk of complications, and the cost of these techniques also must be considered.

The sagittal spinal profile type: a principal precondition for surgical decision making in patients with lumbar spinal stenosis

OBJECTIVE

Microsurgical decompression (MD) in patients with lumbar spinal stenosis (LSS) shows good clinical results. Nevertheless, 30%–40% of patients do not have a significant benefit after surgery—probably due to different anatomical preconditions. The sagittal profile types (SPTs 1–4) defined by Roussouly based on different spinopelvic parameters have been shown to influence spinal degeneration and surgical results. The aim of this study was to investigate the influence of the SPT on the clinical outcome in patients with LSS who were treated with MD.

METHODS

The authors retrospectively investigated 100 patients with LSS who received MD. The patients were subdivided into 4 groups depending on their SPT, which was determined from preoperative lateral spinal radiographs. The authors analyzed pre- and postoperative outcome scales, including the visual analog scale (VAS), walking distance, Oswestry Disability Index, Roland-Morris Disability Questionnaire, Odom’s criteria, and the 36-Item Short Form Health Survey score.

RESULTS

Patients with SPT 1 showed a significantly worse clinical outcome concerning their postoperative back pain (VASback-SPT 1 = 5.4 ± 2.8; VASback-SPT 2 = 2.6 ± 1.9; VASback-SPT 3 = 2.9 ± 2.6; VASback-SPT 4 = 1.5 ± 2.5) and back pain–related disability. Only 43% were satisfied with their surgical results, compared with 70%–80% in the other groups.

CONCLUSIONS

A small pelvic incidence with reduced compensation mechanisms, a distinct lordosis in the lower lumbar spine with a high load on dorsal structures, and a long thoracolumbar kyphosis with a high axial load might lead to worse back pain after MD. Therefore, the indication for MD should be provided carefully, fusion can be considered, and other possible reasons for back pain should be thoroughly evaluated and treated.

Clinical outcomes after minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion for treatment of degenerative lumbar disease: a systematic review and meta-analysis

The surgical procedures used for arthrodesis in the lumbar spine for degenerative lumbar diseases remain controversial. This systematic review aims to assess and compare clinical outcomes along with the complications and fusion of each technique (minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or minimally invasive lateral lumbar interbody fusion (MIS LLIF)) for treatment of degenerative lumbar diseases. Relevant studies were identified from Medline and Scopus from inception to July 19, 2016 that reported Oswestry Disability Index (ODI), back and leg pain visual analog score (VAS), postoperative complications, and fusion of either technique. Fifty-eight studies were included for the analysis of MIS-TLIF; 40 studies were included for analysis of LLIF, and 1 randomized controlled trial (RCT) study was included for comparison of MIS-TLIF to LLIF. Overall, there were 9506 patients (5728 in the MIS-TLIF group and 3778 in the LLIF group). Indirect meta-analysis, MIS-TLIF provided better postoperative back and leg pain (VAS), disabilities (ODI), and risk of having complications when compared to LLIF technique, but the fusion rate was not significantly different between the two techniques. However, direct meta-analysis between RCT study and pooled indirect meta-analysis of MIS-TLIF have better pain, disabilities, and complication but no statistically significant difference when compared to LLIF. In LLIF, the pooled mean ODI and VAS back pain were 2.91 (95% CI 2.49, 3.33) and 23.24 (95% CI 18.96, 27.51) in MIS approach whereas 3.14 (95% CI 2.29, 4.04) and 28.29 (95% CI 21.92, 34.67) in traditional approach. In terms of complications and fusion rate, there was no difference in both groups. In lumbar interbody fusion, MIS-TLIF had better ODI, VAS pain, and complication rate when compared to LLIF with direct and indirect meta-analysis methods. However, in terms of fusion rates, there were no differences between the two techniques.

Comparison of complication rates of minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion: a systematic review of the literature

OBJECT Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and lateral lumbar interbody fusion (LLIF) are 2 currently popular techniques for lumbar arthrodesis. The authors compare the total risk of each procedure, along with other important complication outcomes. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies (up to May 2015) that reported complications of either MI-TLIF or LLIF were identified from a search in the PubMed database. The primary outcome was overall risk of complication per patient. Secondary outcomes included risks of sensory deficits, temporary neurological deficit, permanent neurological deficit, intraoperative complications, medical complications, wound complications, hardware failure, subsidence, and reoperation. RESULTS Fifty-four studies were included for analysis of MI-TLIF, and 42 studies were included for analysis of LLIF. Overall, there were 9714 patients (5454 in the MI-TLIF group and 4260 in the LLIF group) with 13,230 levels fused (6040 in the MI-TLIF group and 7190 in the LLIF group). A total of 1045 complications in the MI-TLIF group and 1339 complications in the LLIF group were reported. The total complication rate per patient was 19.2% in the MI-TLIF group and 31.4% in the LLIF group (p < 0.0001). The rate of sensory deficits and temporary neurological deficits, and permanent neurological deficits was 20.16%, 2.22%, and 1.01% for MI-TLIF versus 27.08%, 9.40%, and 2.46% for LLIF, respectively (p < 0.0001, p < 0.0001, p = 0.002, respectively). Rates of intraoperative and wound complications were 3.57% and 1.63% for MI-TLIF compared with 1.93% and 0.80% for LLIF, respectively (p = 0.0003 and p = 0.034, respectively). No significant differences were noted for medical complications or reoperation. CONCLUSIONS While there was a higher overall complication rate with LLIF, MI-TLIF and LLIF both have acceptable complication profiles. LLIF had higher rates of sensory as well as temporary and permanent neurological symptoms, although rates of intraoperative and wound complications were less than MI-TLIF. Larger, prospective comparative studies are needed to confirm these findings as the current literature is of relative poor quality.

MASTERS-D Study: A Prospective, Multicenter, Pragmatic, Observational, Data-Monitored Trial of Minimally Invasive Fusion to Treat Degenerative Lumbar Disorders, One-Year Follow-Up

The objective of the study is to assess effectiveness and safety of minimally invasive lumbar interbody fusion (MILIF) for degenerative lumbar disorders (DLD) in daily surgical practice and follow up with patients for one year after surgery.

A prospective, multicenter, pragmatic, monitored, international outcome study in patients with DLD causing back/leg pain was conducted (19 centers). Two hundred fifty-two patients received standard of care available in the centers. Patients were included if they were aged >18 years, required one- or two-level lumbar fusion for DLD, and met the criteria for approved device indications. Primary endpoints: time to first ambulation (TFA) and time to surgery recovery (TSR). Secondary endpoints: patient-reported outcomes (PROs)--back and leg pain (visual analog scale), disability (Oswestry Disability Index (ODI)), health status (EQ-5D), fusion rates, reoperation rates, change in pain medication, rehabilitation, return to work, patient satisfaction, and adverse events (AEs). Experienced surgeons (≥30 surgeries pre-study) treated patients with DLD by one- or two-level MILIF and patients were evaluated for one year (NCT01143324).

At one year, 92% (233/252) of patients remained in the study. Primary outcomes: TFA, 1.3 ±0.5 days and TSR, 3.2 ±2.0 days. Secondary outcomes: Most patients (83.3%) received one level MILIF; one (two-level) MILIF mean surgery duration, 128 (182) min; fluoroscopy time, 115 (154) sec; blood loss, 164 (233) mL; at one year statistically significant (P<.0001) and clinically meaningful changes from baseline were reported in all PROs--reduced back pain (2.9 ±2.5 vs. 6.2 ±2.3 at intake), reduced leg pain (2.2 ±2.6 vs. 5.9 ±2.8), and ODI (22.4% ± 18.6 vs. 45.3% ± 15.3), as well as health-related quality of life (EQ-5D index: 0.71 ±0.28 vs. 0.34 ±0.32). More of the professional workers were working at one year than those prior to surgery (70.3% vs. 55.2%). Three AEs and one serious AE were considered procedure-related; there were no deep site infections or deaths.

This is the first study evaluating MILIF for treatment of DLD in daily clinical practice. Clinically significant improvements were observed in all endpoints. Short-term post-surgery improvements (four weeks) were maintained through one year with minimal complications. Our results suggest that MILIF has good-to-excellent outcomes for the treatment of DLD in a broad patient population under different clinical conditions and healthcare delivery systems.

Comparison of Clinical Outcomes in the National Neurosurgery Quality and Outcomes Database for Open Versus Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

A retrospective database review.

OBJECTIVE

The aim of this study was to compare data on various pain and functional outcomes for patients who underwent minimally invasive transforaminal lumbar interbody fusion (MiTLIF) and those who had open TLIF to better delineate which patients may benefit from each procedure.

SUMMARY OF BACKGROUND DATA

TLIF is a highly successful technique for the treatment of patients with degenerative instability or deformity. Minimally invasive approaches have been developed in an effort to improve outcomes by reducing tissue trauma and minimizing surgical time and blood loss. Although these approaches have been compared in the literature, there continues to be a debate about which patients may benefit from each procedure, and there is a dearth of information regarding short-term outcomes such as disposition status.

METHODS

We used the National Neurosurgery Quality and Outcomes Database (N2QOD) to assess outcomes of patients who underwent open or MiTLIF at a single institution from 2012 to 2014. Primary outcomes included Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) scores, and secondary outcomes included hospital length of stay, blood loss, discharge status, and return to work.

RESULTS

We identified 98 patients with 3- and 12-month follow-up records. The open and MiTLIF groups had similar improvements in ODI and VAS at 3 and 12 months. MiTLIF patients had a significantly longer hospital stay (5.0 vs. 3.8 days for open TLIF, P < 0.001) and were more likely to discharge to a location other than home (P < 0.021). Open TLIF patients had shorter mean operative time (235 vs. 329 minutes for MiTLIF, P < 0.001) and more blood loss (307 vs. 120.2 mL for MiTLIF, P < 0.001).

CONCLUSION

Although each approach demonstrated advantages and disadvantages, outcome measures at short-term follow-up were largely equivalent, suggesting that the selection of procedure should be based on which approach will offer the superior individual outcome.

LEVEL OF EVIDENCE

4.