Degenerative Spondylolisthesis: An Analysis of the Nationwide Inpatient Sample Database

Are the facet joint parameters risk factors for cage subsidence after TLIF in patients with lumbar degenerative spondylolisthesis?

PURPOSE

To assess whether preoperative facet joint parameters in patients with degenerative lumbar spondylolisthesis (DS) are risk factors for cage subsidence (CS) following transforaminal lumbar interbody fusion (TLIF).

METHODS

We enrolled 112 patients with L4-5 DS who underwent TLIF and were followed up for > 1 year. Preoperative demographic characteristics, functional areas of paraspinal muscles and psoas major muscles (PS), total functional area relative to vertebral body area, functional cross-sectional area (FCSA) of PS and lumbar spine extensor muscles, normalized FCSA of PS to the vertebral body area (FCSA/VBA), lumbar indentation value, facet joint orientation, facet joint tropism (FT), cross-sectional area of the superior articular process (SAPA), intervertebral height index, vertebral Hounsfield unit (HU) value, lordosis distribution index, t-scores, sagittal plane parameters, visual analog scale (VAS) for low back pain, VAS for leg pain, Oswestry disability index, global alignment and proportion score and European quality of life-5 dimensions (EQ-5D) were assessed.

RESULTS

Postoperative CS showed significant correlations with preoperative FO(L3-4), FT (L3 and L5), SAPA(L3-5), L5-HU, FCSA/VBA(L3-4), Pre- T-score, post-6-month VAS for back pain and EQ-5D scores among other factors. According to ROC curve analysis, the optimal decision points for FO(L3-4), L3-SAPA, FCSA/VBA(L3-4), L5-HU, and Pre- T-score were 35.88°, 43.76°,114.93, 1.73, 1.55, 136, and - 2.49.

CONCLUSIONS

This study identified preoperative FO, SAPA, preoperative CT, Pre- T-score and the FCSA/VBA as independent risk factors for CS after TLIF for DS. These risk factors should enable spinal surgeons to closely monitor and prevent the occurrence of CS.

Patient reported outcomes after navigated minimally invasive hybrid lumbar interbody fusion (nMIS-HLIF) using cortical bone trajectory screws

Prospective observational study. To evaluate patient-reported outcomes after navigation-guided minimally invasive hybrid lumbar interbody fusion (nMIS-HLIF) for decompression and fusion in degenerative spondylolisthesis (Meyerding grade I-II). Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) are well-known standard procedures for lumbar spinal fusion. nMIS-HLIF is a navigation-guided combined percutaneous and open procedure that combines the advantages of PLIF and TLIF procedures for the preparation of a single-port endoscopic approach. 33 patients underwent nMIS-HLIF. Core outcome measure index (COMI), oswestry disability index (ODI), numeric rating scale (NRS) back, NRS leg, and short form health-36 (SF-36) were collected preoperatively and at follow-up of 6 weeks, 3 months, 6 months, and 1 year. The impact of body mass index (BMI) was also analyzed. Computed tomography reconstruction was used to assess realignment and verify fused facet joints and vertebral bodies at the 1-year follow-up. 28 (85%) completed the 1-year follow-up. The median BMI was 27.6 kg/m2, age 69 yrs. The mean reduction in listhesis was 8.4% (P < .01). BMI was negatively correlated with listhesis reduction (P = .032). The improvements in the NRS back, NRS leg, ODI, and COMI scores were significant at all times (P < .001-P < .01). The SF-36 parameters of bodily pain, physical functioning, physical component summary, role functioning/physical functioning, and social functioning improved (P < .003). The complication rate was 15.2% (n = 5), with durotomy (n = 3) being the most frequent. To reduce the complication rate and allow transitioning to a fully endoscopic approach, expandable devices have been developed. The outcomes of nMIS-HLIF are comparable to the current standard open and minimally invasive techniques. A high BMI hinders this reduction. The nMIS-HLIF procedure is appropriate for learning minimally invasive dorsal lumbar stabilization. The presented modifications will enable single-port endoscopic lumbar stabilization in the future.

Current treatment and decision-making factors leading to fusion vs decompression for one-level degenerative spondylolisthesis: survey results from members of the Lumbar Spine Research Society and Society of Minimally Invasive Spine Surgery

BACKGROUND

Degenerative spondylolisthesis (DS) is one of the most common pathologies spine surgeons treat. While a number of potential factors have been identified, there is no current consensus on which variables most impact the decision to fuse vs. decompress alone in this population.

PURPOSE

The purpose of this study was to describe current DS treatment practices and identify both the radiographic and clinical factors leading to the decision to fuse segments for one level DS.

STUDY DESIGN/SETTING

Descriptive cross-sectional survey.

PATIENT SAMPLE

Surveys were administered to members of Lumbar Spine Research Society and Society of Minimally Invasive Spine Surgery.

OUTCOME MEASURES

Surgeon demographics and treatment practices were reported. Radiographic and clinical parameters were ranked by each surgeon with regards to their importance.

METHODS

The primary analysis was limited to completed surveys. Baseline characteristics were summarized. Clinical and radiographic parameters were ranked and compared. Ranking of each clinical and radiographic parameters was reported using best and worst rank, mean rank position, and percentiles. The most important, top 3 most important, and top 5 most important parameters were ordered given each parameter's ranking frequency.

RESULTS

381 surveys were returned completed. With regards to fusion vs. decompression, 19.9% fuse all cases, 39.1% fuse > 75%, 17.8% fuse 50%-75%, and 23.2% fuse <25%. The most common decompressive technique was a partial laminotomy (51.4%), followed by full laminectomy (28.9%). 82.2% of respondents instrument all fusion cases. Instability (93.2%), spondylolisthesis grade (59.8%), and laterolisthesis (37.3%) were the most common radiographic factors impacting the decision to fuse. With regards to the clinical factors leading to fusion, mechanical low back pain (83.2%), activity level (58.3%), and neurogenic claudication (42.8%) were the top 3 clinical parameters.

CONCLUSIONS

There is little consensus on the treatment of DS, with society members showing substantial variation in treatment patterns with the majority utilizing fusion for treatment. The most common radiographic parameters impacting treatment are instability, spondylolisthesis grade, and laterolisthesis while mechanical low back pain, activity level, and neurogenic claudication are the most common clinical parameters.

Trends in Single-Level Lumbar Fusions Over the Past Decade Using a National Database

OBJECTIVE

To compare rates of different fusion techniques using a nationwide database over the last decade and identify differences in complications and readmissions based on fusion technique.

METHODS

All elective, single-level lumbar fusions performed by orthopaedic surgeons from 2011 to 2020 were identified from the American College of Surgeons National Surgical Quality Improvement Program. Rates of lumbar fusion technique posterolateral decompression and fusion [PLDF], combined transforaminal lumbar interbody fusion and PLDF, anterior lumbar or lateral lumbar interbody fusion [ALIF/LLIF], and combined ALIF/LLIF and PLDF were recorded, and 30-day complications and readmissions were compared. Secondary analysis included multiple logistic regression to determine independent predictors of each outcome.

RESULTS

Inclusion criteria were met by 28,413 fusions: 8749 (30.8%) PLDFs, 11,973 (42.1%) transforaminal lumbar interbody fusions, 4769 (16.8%) ALIF/LLIFs, and 2922 (10.3%) combined ALIF/LLIF and PLDFs. The number of fusions increased over time with 1227 fusions performed in 2011 and 3958 fusions performed in 2019. Interbody fusions also increased over time with a subsequent decrease in PLDFs (39.0% in 2011, 25.2% in 2020). Patients were more likely to be discharged home over the course of the decade (85.4% in 2011, 95.0% in 2020). No difference was observed between the techniques regarding complications or readmissions. The modified 5-item frailty index was predictive of complications (odds ratio, 2.05; P = 0.001) and readmissions (odds ratio, 2.61; P < 0.001).

CONCLUSIONS

Lumbar fusions have continued to increase over the last decade with an increasing proportion of interbody fusions. Complications and readmissions appear to be driven by patient comorbidity and not fusion technique.

Practice Variation Research in Degenerative Lumbar Disc Surgery: A Literature Review on Design Characteristics and Outcomes

STUDY DESIGN

Literature review.

OBJECTIVE

To describe whether practice variation studies on surgery in patients with lumbar degenerative disc disease used adequate study methodology to identify unwarranted variation, and to inform quality improvement in clinical practice. Secondary aim was to describe whether variation changed over time.

METHODS

Literature databases were searched up to May 4^th, 2021. To define whether study design was appropriate to identify unwarranted variation, we extracted data on level of aggregation, study population, and case-mix correction. To define whether studies were appropriate to achieve quality improvement, data were extracted on outcomes, explanatory variables, description of scientific basis, and given recommendations. Spearman's rho was used to determine the association between the Extreme Quotient (EQ) and year of publication.

RESULTS

We identified 34 articles published between 1990 and 2020. Twenty-six articles (76%) defined the diagnosis. Prior surgery cases were excluded or adjusted for in 5 articles (15%). Twenty-three articles (68%) adjusted for case-mix. Variation in outcomes was analyzed in 7 articles (21%). Fourteen articles (41%) identified explanatory variables. Twenty-six articles (76%) described the evidence on effectiveness. Recommendations for clinical practice were given in 9 articles (26%). Extreme Quotients ranged between 1-fold and 15-fold variation and did not show a significant change over time (rho= -.33, P= .09).

CONCLUSIONS

Practice variation research on surgery in patients with degenerative disc disease showed important limitations to identify unwarranted variation and to achieve quality improvement by public reporting. Despite the availability of new evidence, we could not observe a significant decrease in variation over time.

Comparison between modified facet joint fusion and posterolateral fusion for the treatment of lumbar degenerative diseases: a retrospective study

Objective

To investigate the safety and effectiveness of modified facet joint fusion in the treatment of lumbar degenerative diseases and compare them with those of posterolateral fusion.

Methods

A total of 77 adult patients with lumbar degenerative disease diagnosed from January 2017 to February 2019 were considered for the present retrospective, nonrandomized, and controlled study. The patients were divided into two groups according to the fusion technique used during the surgery: the posterolateral fusion (PLF) group (n = 42) and the modified facet joint fusion (MFF) group (n = 35). The fusion rate, Oswestry Disability Index (ODI) score, visual analog scale (VAS) score for back pain and leg pain, Japanese Orthopedic Association (JOA) score, European Quality of Life–5 Dimensions (EQ-5D) score, length of hospital stay, length of operation, intraoperative blood loss, cost of hospitalization, complications and reoperations were compared between the 2 groups.

Results

All patients underwent a successful surgery, and all were followed up. No significant differences were found in age, sex, BMI, length of hospital stay, length of operation or cost of hospitalization. There were no significant differences in the preoperative or postoperative ODI or in the VAS, JOA, and EQ-5D scores between the MFF and PLF groups. However, the fusion rate of MFF group was higher than that of the PLF group (P < 0.05). What’s more, the MFF group had less intraoperative blood loss than the PLF group (P < 0.05). Complications related to iatrogenic nerve injury, vascular injury, epidural hematoma, intravertebral infection, and internal fixation did not occur in either group. None of the patients required reoperation.

Conclusions

Modified facet joint fusion is safe and efficient in the treatment of lumbar degenerative disease. The fusion rate of MFF was higher than PLF. The intraoperative blood loss of MFF was less than that of PLF. In addition, the therapeutic effect of MFF was not worse than that of PLF. Therefore, the MFF technique can be promoted in clinical treatment.

Is Discretionary Care Associated with Safety Among Medicare Beneficiaries Undergoing Spine Surgery?

BACKGROUND

Spine surgery and its corresponding costs have increased in recent years and are variable across geographic regions. Discretionary care is the component of spending variation that is independent of illness severity, age, and regional pricing. It is unknown whether greater discretionary care is associated with improved safety for patients undergoing spine surgery, as we would expect from value-based health care.

METHODS

We conducted an analysis of 5 spine surgery cohorts based on Medicare claims from 2013 to 2017. Patients were grouped into quintiles based on the Dartmouth Atlas End-of-Life Inpatient Care Index (EOL), reflecting regional spending variation attributed to discretionary care. Multivariable regression examined the association between discretionary care and safety measures while controlling for age, sex, race, comorbidity, and hospital features.

RESULTS

We observed a threefold to fourfold variation in 90-day episode-of-care cost across regions, depending on the cohort. Spine-specific spending was correlated with EOL quintile, confirming that spending variation is due more to discretionary care than it is to pricing, age, or illness severity. Greater spending across EOL quintiles was not associated with improved safety, and, in fact, was associated with poorer safety in some cohorts. For example, all-cause readmission was greater in the high-spending EOL quintile relative to the low-spending EOL quintile among the "fusion, except cervical" cohort (14.2% vs. 13.1%; OR = 1.10; 95% CI = 1.05 to 1.20), the "complex fusion" cohort (28.0% vs. 25.4%; OR = 1.15; 95% CI = 1.01 to 1.30), and the "cervical fusion" cohort (15.0% vs. 13.6%; OR = 1.12; 95% CI = 1.05 to 1.20).

CONCLUSIONS

Wide variation in spending was not explained by differences in illness severity, age, or pricing, and increased discretionary care did not enhance safety. These findings point to inefficient use of health-care resources, a potential focus of reform.

LEVEL OF EVIDENCE

Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

A BMP/Activin A Chimera Induces Posterolateral Spine Fusion in Nonhuman Primates at Lower Concentrations Than BMP-2

BACKGROUND

Supraphysiologic bone morphogenetic protein (BMP)-2 concentrations are required to induce spinal fusion. In this study, a BMP-2/BMP-6/activin A chimera (BV-265), optimized for BMP receptor binding, delivered in a recombinant human collagen:CDHA [calcium-deficient hydroxyapatite] porous composite matrix (CM) or bovine collagen:CDHA granule porous composite matrix (PCM), engineered for optimal BV-265 retention and guided tissue repair, was compared with BMP-2 delivered in a bovine absorbable collagen sponge (ACS) wrapped around a MASTERGRAFT Matrix (MM) ceramic-collagen rod (ACS:MM) in a nonhuman primate noninstrumented posterolateral fusion (PLF) model.

METHODS

In vivo retention of 125I-labeled-BV-265/CM or PCM was compared with 125I-labeled-BMP-2/ACS or BMP-2/buffer in a rat muscle pouch model using scintigraphy. Noninstrumented PLF was performed by implanting CM, BV-265/CM, BV-265/PCM, or BMP-2/ACS:MM across L3-L4 and L5-L6 or L3-L4-L5 decorticated transverse processes in 26 monkeys. Computed tomography (CT) images were acquired at 0, 4, 8, 12, and 24 weeks after surgery, where applicable. Manual palpation, μCT (microcomputed tomography) or nCT (nanocomputed tomography), and histological analysis were performed following euthanasia.

RESULTS

Retention of 125I-labeled-BV-265/CM was greater than BV-265/PCM, followed by BMP-2/ACS and BMP-2/buffer. The CM, 0.43 mg/cm3 BMP-2/ACS:MM, and 0.05 mg/cm3 BV-265/CM failed to generate PLFs. The 0.15-mg/cm3 BV-265/CM or 0.075-mg/cm3 BV-265/PCM combinations were partially effective. The 0.25-mg/cm3 BV-265/CM and 0.15 and 0.3-mg/cm3 BV-265/PCM combinations generated successful 2-level PLFs at 12 and 24 weeks.

CONCLUSIONS

BV-265/CM or PCM can induce fusion in a challenging nonhuman primate noninstrumented PLF model at substantially lower concentrations than BMP-2/ACS:MM.

CLINICAL RELEVANCE

BV-265/CM and PCM represent potential alternatives to induce PLF in humans at substantially lower concentrations than BMP-2/ACS:MM.

Lumbar Fusion for Spondylolisthesis: A Bayesian Network Meta-analysis of Randomized Controlled Trials

STUDY DESIGN

This was a Bayesian network meta-analysis.

OBJECTIVE

We aimed to assess the comparative efficacies of the 5 most commonly used procedures for spondylolisthesis in a Bayesian network meta-analysis.

SUMMARY OF BACKGROUND

Lumbar fusion procedures are the backbone for the surgical treatment of spondylolisthesis. However, the current evidence has only considered head-to-head comparisons of different fusion procedures and failed to definitively favor one fusion procedure over another.

MATERIALS AND METHODS

A Bayesian random-effects model was used, and radiographic fusion and complications were assessed by risk ratio with a corresponding 95% credible interval; Oswestry Disability Index (ODI) scores were assessed by mean difference and 95% credible interval. Furthermore, with respect to each endpoint, ranking probabilities for each fusion procedure were evaluated using the value of the surface under the cumulative ranking curve.

RESULTS

In all, 12 studies were identified. Significant differences in associated complications were found between minimally invasive transforaminal lumbar interbody fusion (MTLIF) and each of the other 4 fusion procedures. Surface under the cumulative ranking curve results suggested that for the most effective radiographic fusion, open transforaminal lumbar interbody fusion (OTLIF) had the maximum probability of being successful (76.6%), followed by MTLIF (70.4%) and open posterior lumbar interbody fusion (OPLIF, 48.7%). In terms of ODI scores, OTLIF might be the best intervention (70.5%), followed by MTLIF (68.8%) and then OPLIF (44.0%). However, MTLIF is ranked the safest (99.8%) regarding associated complications, followed sequentially by OTLIF (57.1%) and posterolateral fusion (30.1%).

CONCLUSIONS

OTLIF for spondylolisthesis was found to be the more efficient procedure in terms of radiographic fusion and ODI scores. Importantly, MTLIF is most likely to have a lower associated complication rate compared with other fusion procedures.

National utilization and inpatient safety measures of lumbar spinal fusion methods by race/ethnicity

BACKGROUND CONTEXT

Degenerative lumbar conditions are prevalent, disabling, and frequently managed with decompression and fusion. Black patients have lower spinal fusion rates than White patients.

PURPOSE

Determine whether specific lumbar fusion procedure utilization differs by race/ethnicity and whether length of stay (LOS) or inpatient complications differ by race/ethnicity after accounting for procedure performed.

STUDY DESIGN

Large database retrospective cohort study PATIENT SAMPLE: Lumbar fusion recipients at least age 50 in the 2016 National Inpatient Sample with diagnoses of degenerative lumbar conditions.

OUTCOME MEASURES

Type of fusion procedure used and inpatient safety measures including LOS, prolonged LOS, inpatient medical and surgical complications, mortality, and cost.

METHODS

We examined the association between race/ethnicity and the safety measures above. Covariates included several patient and hospital factors. We used multiple linear or logistic regression to determine the association between race and fusion type (PLF, P/TLIF, ALIF, PLF + P/TLIF, and PLF + ALIF [anterior-posterior fusion]) and to determine whether race was associated independently with inpatient safety measures, after adjustment for patient and hospital factors.

RESULTS

Fusion method use did not differ among racial/ethnic groups, except for somewhat lower anterior-posterior fusion utilization in Black patients compared to White patients (crude odds ratio [OR]: 0.81 [0.67-0.97]). Inpatient safety measures differed by race/ethnicity for rates of prolonged LOS (Blacks 18.1%, Hispanics 14.5%, and Whites 11.7%), medical complications (Blacks 9.9%, Hispanics 8.7%, and Whites 7.7%), and surgical complications (Blacks 5.2%, Hispanics 6.9%, and Whites 5.4%). Differences persisted after adjustment for procedure type as well as patient and hospital factors. Blacks and Hispanics had higher risk for prolonged LOS compared to Whites (adjusted OR Blacks 1.39 [95% confidence interval {CI} 1.22-1.59]; Hispanics 1.24 [95% CI 1.02-1.52]). Blacks had higher risk for inpatient medical complications compared to Whites (adjusted OR 1.24 [95% CI 1.05-1.48]), and Hispanics had higher risk for inpatient surgical complications compared to Whites (adjusted OR 1.34 [95% CI 1.06-1.68]).

CONCLUSIONS

Fusion method use was generally similar between racial/ethnic groups. Inpatient safety measures, adjusted for procedure type, patient and hospital factors, were worse for Blacks and Hispanics.

Additive-manufactured Ti-6Al-4 V/Polyetheretherketone composite porous cage for Interbody fusion: bone growth and biocompatibility evaluation in a porcine model

Background

We developed a porous Ti alloy/PEEK composite interbody cage by utilizing the advantages of polyetheretherketone (PEEK) and titanium alloy (Ti alloy) in combination with additive manufacturing technology.

Methods

Porous Ti alloy/PEEK composite cages were manufactured using various controlled porosities. Anterior intervertebral lumbar fusion and posterior augmentation were performed at three vertebral levels on 20 female pigs. Each level was randomly implanted with one of the five cages that were tested: a commercialized pure PEEK cage, a Ti alloy/PEEK composite cage with nonporous Ti alloy endplates, and three composite cages with porosities of 40, 60, and 80%, respectively. Micro-computed tomography (CT), backscattered-electron SEM (BSE-SEM), and histological analyses were performed.

Results

Micro-CT and histological analyses revealed improved bone growth in high-porosity groups. Micro-CT and BSE-SEM demonstrated that structures with high porosities, especially 60 and 80%, facilitated more bone formation inside the implant but not outside the implant. Histological analysis also showed that bone formation was higher in Ti alloy groups than in the PEEK group.

Conclusion

The composite cage presents the biological advantages of Ti alloy porous endplates and the mechanical and radiographic advantages of the PEEK central core, which makes it suitable for use as a single implant for intervertebral fusion.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04022-0.

Modified Facet Joint Fusion for Lumbar Degenerative Disease: Case Series of a Fusion Technique, Clinical Outcomes, and Fusion Rate in 491 Patients

BACKGROUND

Controversy still exists regarding the optimal fusion technique for the treatment of unstable lumbar spondylolisthesis.

OBJECTIVE

To evaluate the safety and efficacy of modified facet joint fusion (MFF).

METHODS

A total of 491 patients with unstable lumbar spondylolisthesis who underwent MFF were retrospectively reviewed. Computed tomography was used to evaluate the fusion rate of MFF at 6- and 12-mo follow-up postoperatively. Clinical outcomes included visual analog scale pain scores for low back pain (VAS-LBP) and leg pain (VAS-LP), Japanese Orthopedic Association scores (JOA), and Oswestry Disability Index (ODI), all of which were obtained preoperatively and postoperatively at 1-, 3-, 6-, and 12-mo follow-up times. The clinical outcomes were determined to be excellent, good, fair, or poor according to the MacNab classification at the last follow-up time.

RESULTS

Of the 491 patients, the fusion rates at the 6-mo and 1-yr follow-up were 56.8% and 96.1%, respectively. Between baseline and 1-yr follow-up time, VAS-LP and VAS-LBP improved from 5.6 ± 0.9 to 0.4 ± 0.5 and 5.1 ± 1.2 to 1.5 ± 0.9, respectively (P < .001). JOA improved from 9.0 ± 2.0 to 27.7 ± 1.0, and ODI decreased from 64.0 ± 2.0 to 19 ± 1.0 (P < .001). At the final evaluation, 93.6% patients showed excellent or good results, and 3.2% showed fair results. There were no MFF technique-related complications.

CONCLUSION

MFF technique achieved satisfactory clinical outcomes and fusion rate and appears to be a promising alternative fusion technique for the treatment of unstable lumbar spondylolisthesis.

Comparing rates of early pedicle screw loosening in posterolateral lumbar fusion with and without transforaminal lumbar interbody fusion

BACKGROUND CONTEXT

Addition of interbody fusion via a transforaminal approach (TLIF) has become a popular surgical option for treatment of degenerative lumbar conditions. Although technically more complicated than posterolateral fusion surgery (PLF), it has been suggested that TLIF provides superior immediate stability and protects against early pedicle screw loosening. This theory has never been formally examined in a clinical study.

PURPOSE

To determine the impact of TLIF on early pedicle screw loosening and radiographic fusion rates compared with PLF using pedicle screws alone in the treatment of single level lumbar degenerative conditions.

STUDY DESIGN

Retrospective computed tomography (CT) based review.

PATIENT SAMPLE

One hundred ninety-three patients underwent TLIF+PLF with local autograft bone or PLF alone with local autograft bone.

OUTCOME MEASURES

Radiographic fusion rates and screw loosening were measured at 6 and 12 months using strict CT criteria. Patient self-reported outcome measures included Visual Analog Scale for low back pain and leg pain and Oswestry Disability Index.

METHODS

Postoperative thin-cut CTs were examined for pedicle screw loosening and radiographic fusion status. Early screw loosening rates were determined using 6-month postoperative CT, whereas radiographic fusion rates were determined using 12-month postoperative CT. One-way analysis of variance was used to determine significant differences in mean outcome scores and other continuous measures between groups at baseline and follow-up. Chi-square test of independence or Fisher's exact test was used to compare proportions between groups on categorical measures.

RESULTS

Eighty-three patients underwent TLIF+PLF (Group A) and 115 patients underwent PLF alone (Group B). At 6-month follow-up, loosening was observed in 49 of 792 total screws (6.19%). Of Group A, 7.23% of patients demonstrated loosening of one or more screws compared with 18.3% of Group B (Chi-Square value 4.98; p=.0256). Six-month radiographic fusion rates were 36.1% in Group A versus 44.3% in Group B. Twelve-month radiographic fusion rates increased to 58.6% in Group A versus 73.1% in Group B. Among Group A patients not yet fused at 6 months, screw loosening was associated with a 0% rate of radiographic fusion at 12 months versus 41.2% without screw loosening. Rates for Group B were 6.25% and 70.3%, respectively. Patient age was a significant independent predictor of loosening (p=.0336).

CONCLUSIONS

TLIF appears to have a protective effect, reducing rates of early screw loosening by approximately 60% versus PLF. However, this effect appears independent of actual overall radiographic fusion rates which may be approximately 20% lower with TLIF at 12 months. TLIF may have advantages in patients where early loosening is a particular concern, for example, in the setting of increased patient age.

Polyetheretherketone Versus Titanium Cages for Posterior Lumbar Interbody Fusion: Meta-Analysis and Review of the Literature

Objective

Lumbar fusion with implantation of interbody cage is a common procedure for treatment of lumbar degenerative disease. This study aims to compare the fusion and subsidence rates of titanium (Ti) versus polyetheretherketone (PEEK) interbody cages after posterior lumbar interbody fusion and investigate the effect of clinical and radiological outcomes following fusion on patient-reported outcomes.

Methods

A systematic search strategy of 4 electronic databases (MEDLINE, Embase, Web of Science, and Cochrane) was conducted using different MeSH (medical subject headings) terms until January 2020. Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using fixed and random-effect models based upon the heterogeneity (I²) to estimate the association between interbody cages and the measured outcomes.

Results

A total of 1,094 patients from 11 studies were reviewed. The final analysis included 421 patients (38.5%) who had lumbar surgery using a Ti and/or a Ti-coated interbody cage and 673 patient (61.5%) who had lumbar surgery using a PEEK cage. Overall, PEEK interbody devices were associated with a significantly lower fusion rate compared with Ti interbody devices (OR, 0.62; 95% CI, 0.41–0.93; p = 0.02). There was no difference in subsidence rates between Ti and PEEK groups (OR, 0.91; 95% CI, 0.54–1.52; p = 0.71). Also, there were no statistically significant differences in visual analogue scale (VAS)-low back pain (p = 0.14) and Japanese Orthopedic Association scale (p = 0.86) between the 2 groups. However, the PEEK group had lower odds of leg pain after surgery compared to the Ti group (OR [VAS-leg], 0.61; 95% CI, 0.28–0.94; p = 0.003).

Conclusion

Ti and Ti-coated PEEK cages used for posterior lumbar interbody fusion are associated with similar rates of subsidence, but a higher rate of fusion compared to PEEK interbody cages. Randomized controlled trials are needed to better assess the effect of cage materials and potential factors that could influence the outcomes of interbody lumbar fusion.

Fusion technique does not affect short-term patient-reported outcomes for lumbar degenerative disease

BACKGROUND/CONTEXT

Degenerative lumbar disease can be addressed via an anterior or posterior approach, and with or without the use of an interbody cage. Although several studies have compared the type of approach and technique, there is a lack of literature assessing patient-reported outcome measures (PROMs) and radiographic parameters between different fusion techniques.

PURPOSE

To determine whether the surgical approach and fusion technique for lumbar degenerative disease had an effect on short-term PROMs and radiographic parameters.

STUDY DESIGN/SETTING

Retrospective Cohort Study.

PATIENT SAMPLE

Three hundred and ninety-one patients who underwent a 1-3 level lumbar spine fusion procedure at a high-volume academic center were retrospectively identified. Patients were divided into three groups based on the type of fusion they underwent: posterolateral fusion (PLF), anterior lumbar interbody fusion (ALIF), or transforaminal lumbar interbody fusion (TLIF).

OUTCOME MEASURES

PROMs: Short Form-12 (SF-12) Physical Component Score (PCS) and Mental Component Score (MCS), Oswestry Disability Index (ODI), Visual Analog Score (VAS) Back, VAS Leg. Spinopelvic measurements: Pelvic Tilt (PT), Sacral Slope (SS), Pelvic Incidence (PI), Lumbar Lordosis (LL), Segmental Lordosis (SL), PI-LL mismatch.

METHODS

Patients with less than 1-year follow-up were excluded from the cohort. Pre- and postoperative spinopelvic measurements were obtained for all patients. Univariate analysis (Chi-squared/Fisher's exact test or ANOVA test with post-hoc Bonferroni test) was used to compare among the three groups in the PROMs and radiographic spinopelvic parameters. Multiple linear regression was used to determine if fusion technique was an independent predictor of change in each patient outcome.

RESULTS

Two hundred and sixteen patients were included in the PLF group, 33 patients in the ALIF group, and 142 patients in the TLIF group. The PLF group was significantly older at baseline (p<.001) and had lower preoperative diagnosis rates of degenerative scoliosis and disc herniations (p<.001), whereas the ALIF group underwent a higher proportion of three-level fusions (p<.001). There was no significant difference in spinopelvic parameters preoperatively, however the ALIF group showed significantly more improvement in SL postoperatively (p=.004) than the PLF and TLIF groups. Within each group, SL improved for the PLF and ALIF groups (p=.002 for both), but not for the TLIF group (p=.238). Comparing patient outcomes, the ALIF group reported lower preoperative VAS Leg scores (p=.031), however, this difference resolved postoperatively. Stratifying for preoperative diagnosis, there were no significant differences in outcomes, except for a greater improvement in VAS Leg scores for degenerative scoliosis patients undergoing ALIF. Using multivariate analysis, fusion technique was not found to be a significant predictor of change in any patient outcome or in odds of revision.

CONCLUSIONS

Lumbar degenerative disease can be treated with several different fusion techniques, however, the relationship between type of fusion and PROMs is not established. Based on the findings in this study, the ALIF group showed greater improvement in SL compared with the PLF and TLIF groups, however, there was no difference noted in overall LL, PI-LL mismatch or other spinopelvic parameters. Despite these radiographic findings, patient outcome measures remained similar between all three fusion types.

Lumbar spondylolisthesis: modern registries and the development of artificial intelligence

OBJECTIVEThere are a wide variety of comparative treatment options in neurosurgery that do not lend themselves to traditional randomized controlled trials. The object of this article was to examine how clinical registries might be used to generate new evidence to support a particular treatment option when comparable options exist. Lumbar spondylolisthesis is used as an example.METHODSThe authors reviewed the literature examining the comparative effectiveness of decompression alone versus decompression with fusion for lumbar stenosis with degenerative spondylolisthesis. Modern data acquisition for the creation of registries was also reviewed with an eye toward how artificial intelligence for the treatment of lumbar spondylolisthesis might be explored.RESULTSCurrent randomized controlled trials differ on the importance of adding fusion when performing decompression for lumbar spondylolisthesis. Standardized approaches to extracting data from the electronic medical record as well as the ability to capture radiographic imaging and incorporate patient-reported outcomes (PROs) will ultimately lead to the development of modern, structured, data-filled registries that will lay the foundation for machine learning.CONCLUSIONSThere is a growing realization that patient experience, satisfaction, and outcomes are essential to improving the overall quality of spine care. There is a need to use practical, validated PRO tools in the quest to optimize outcomes within spine care. Registries will be designed to contain robust clinical data in which predictive analytics can be generated to develop and guide data-driven personalized spine care.

Repeat decompression and fusions following posterolateral fusion versus posterior/transforaminal lumbar interbody fusion for lumbar spondylosis: a national database study

There is a low incidence of reoperation after surgery. It is difficult to detect statistical differences between reoperation rates of different lumbar fusion surgeries. National population-based databases provide large, longitudinally followed cohorts that may help overcome this challenge. The purpose is to compare the repeat decompression and fusion rate after surgery for degenerative lumbar diseases according to different surgical fusion procedures based on national population-based databases and elucidate the risk factor for repeat decompression and fusions. The Korean Health Insurance Review & Assessment Service database was used. Patients diagnosed with degenerative lumbar diseases and who underwent single-level fusion surgeries between January 1, 2011, and June 30, 2016, were included. They were divided into two groups based on procedure codes: posterolateral fusion or posterior/transforaminal lumbar interbody fusion. The primary endpoint was repeat decompression and fusion. Age, sex, the presence of diabetes, osteoporosis, associated comorbidities, and hospital types were considered potential confounding factors. The repeat decompression and fusion rate was not different between the patients who underwent posterolateral fusion and those who underwent posterior/transforaminal lumbar interbody fusion. Old age, male sex, and hospital type were noted to be risk factors. The incidence of repeat decompression and fusion was independent on the fusion method.

Age-related changes in axial and sagittal orientation of the facet joints: Comparison with changes in degenerative spondylolisthesis

BACKGROUND

Despite facet joints being three-dimensional structures, previous computed tomography and magnetic resonance imaging studies have evaluated facet joint orientation in only the axial plane. Facet joint orientation in the sagittal plane has rarely been studied using these imaging techniques. The aim of this study was to elucidate facet joint orientation in both the axial and sagittal planes on computed tomography.

METHODS

A total of 568 patients (343 men, 225 women) (excluding orthopedic outpatients) for whom abdominal and pelvic computed tomography scans were obtained at our hospital between September 2010 and October 2012 were included. Mean age was 63 (range 21-90) years. Patients were divided into a degenerative spondylolisthesis group (67 patients; 30 men, 37 women) and a control group (313 patients; 313 men, 188 women). Facet joint orientation was evaluated in the control group according to patient age (≤50, 51-60, 61-70, or ≥71 years). The findings in the control group were then compared with those in the degenerative spondylolisthesis group. The orientation of the lumbar facet joints at each level was measured in the axial and sagittal planes on computed tomography images.

RESULTS

Facet joint angles decreased with age at L4/5 and L5/S1 in women in the axial plane and at L4/5 in men and L3/4 and L4/5 in women in the sagittal plane. The variation in facet joint angle was greatest at L4/5 in women. Patients with degenerative spondylolisthesis showed more sagittally and horizontally oriented facet joints in the axial and sagittal planes; facet tropism showed an association with degenerative spondylolisthesis in the axial plane.

CONCLUSIONS

The axial and sagittal orientation of facet joints in the lower lumbar vertebra, especially L4/5, was negatively correlated with age. This finding could help to explain why older people are more prone to degenerative spondylolisthesis.

Posterolateral Versus Posterior Interbody Fusion in Lumbar Degenerative Spondylolisthesis

STUDY DESIGN

This was a retrospective study of 2 different fusion techniques for the treatment of lumbar degenerative spondylolisthesis.

OBJECTIVE

To determine whether posterior lumbar interbody fusion (IF) is associated with improved patient-rated satisfaction and functional outcome when compared with posterolateral fusion (PLF).

SUMMARY OF BACKGROUND DATA

IF and PLF are widely used surgical approaches in the treatment of spondylolisthesis. Numerous studies have compared IF and PLF techniques, but inconsistent results, heterogeneous cohorts, and conflicting scientific evidence have made it difficult to reach a consensus on the optimal fusion technique.

MATERIALS AND METHODS

A consecutive cohort of 87 patients who had single-level degenerative spondylolisthesis and either PLF or IF were identified from a prospectively maintained database. Short Form-36 physical and mental component score, Oswestry Disability Index, back and leg pain, and complication rate were assessed to 24 months postoperatively. Patient characteristics, clinical outcome, and complications were compared between groups.

RESULTS

Of the 87 patients identified, 29 patients (33%) had PLF and 58 patients (67%) had IF. Patient follow-up was ≥85%. Foraminal stenosis (PLF, 13.8% vs. IF, 34.5%; P=0.046) was more common among the participants in the IF group. Intraoperative and postoperative complications were not different between groups (P>0.05). The reoperation rate was 3.4% in the PLF group and 10.3% in the IF group (P=0.416). Patients in the PLF group experienced similar gains in improvement in all outcome measures as those in the IF group (P>0.05). Four patients in the IF group and 3 in the PLF group were lacking evidence of radiographic fusion. These patients did have increased moderate back pain compared with patients demonstrating radiographic fusion but did not differ in any other postoperative outcomes measures.

CONCLUSIONS

Type of fusion, IF or PLF, does not affect patient outcome or postoperative complication rates.

LEVEL OF EVIDENCE

Level IV.

Discharge to Inpatient Care Facility After Anterior Lumbar Interbody Fusion: Incidence, Predictors, and Postdischarge Outcomes

BACKGROUND

Despite a significant number of patients being discharged to inpatient care facilities after anterior lumbar interbody fusion (ALIF), the current literature remains limited regarding the predictors associated with a nonhome discharge and the impact of continued inpatient care in a facility on postdischarge outcomes.

METHODS

The 2013-2016 American College of Surgeons National Surgical Quality Improvement Program was queried using Current Procedural Terminology (CPT) codes for ALIF (CPT-22558) and additional level fusions (CPT-22585). Discharge to inpatient care facilities included discharge to skilled care facilities and/or inpatient rehabilitation units.

RESULTS

Independent predictors of an inpatient care facility discharge were age older than 45 years (P < 0.001), female sex (P < 0.001), more than 10% body weight loss in the last 6 months prior to surgery (P=0.012), American Society of Anesthesiologists grade greater than II (P=0.005), undergoing a 2-level (P < 0.001) or more than 2-level fusion (P=0.017), a length of stay greater than 3 days (P < 0.001), and the occurrence of any predischarge complication (P < 0.001). After adjustment for differences in clinical and baseline characteristics between the 2 groups, discharge to an inpatient care facility after ALIF was independently associated with higher odds of any postdischarge complication (P=0.010), postdischarge wound complication (P=0.005), and postdischarge septic complications (P=0.011). No significant impact was seen on 30-day readmissions (P=0.943), 30-day reoperations (P=0.228), and 30-day mortality (P=0.913).

CONCLUSIONS

With an increasing focus toward minimizing costs associated with postacute care, providers should understand the need of appropriate preoperative risk stratification and construction of care pathways aimed at a home discharge to reduce the occurrence and/or risk of experiencing postdischarge complications.

Factors predicting opioid dependence in patients undergoing surgery for degenerative spondylolisthesis: analysis from the MarketScan databases

OBJECTIVE

The opioid crisis is identified as a national emergency and epidemic in the United States. The aim of this study was to identify risk factors associated with opioid dependence in patients undergoing surgery for degenerative spondylolisthesis (DS).

METHODS

The authors queried MarketScan databases to investigate the factors affecting postsurgery opioid use in patients with DS between 2000 and 2012. The outcome of interest was opioid dependence, which was defined as continued opioid use, > 10 opioid prescriptions, or diagnosis of or prescription for opioid dependence disorder in the period of 1 year before or 3–15 months after the procedure. Comparisons of outcomes were performed using nonparametric 2-group tests and generalized regression models.

RESULTS

A cohort of 10,708 patients was identified from the database. The median patient age was 61 years (interquartile range 54–69 years), and 65.1% were female (n = 6975). A majority of patients had decompression with fusion (n = 10,068; 94%) and underwent multilevel procedures (n = 8123; 75.9%). Of 10,708 patients, 14.85% (n = 1591) were identified as having opioid dependence within 12 months prior to the index surgical procedure and 9.90% (n = 1060) were identified as having opioid dependence within 3–15 months after the procedure. Of all the variables, prior opioid dependence (OR 16.29, 95% CI 14.10–18.81, p < 0.001) and younger age (1-year increase in age: OR 0.972, 95% CI 0.963–0.980, p < 0.001) were independent predictors of opioid dependence following surgery for DS. The use of fusion was not associated with opioid dependence following the procedure (p = 0.8396). Following surgery for DS, patients were more likely to become opioid independent than they were to become opioid dependent (8.54% vs 3.58%, p < 0.001).

CONCLUSIONS

The majority of patients underwent fusion for DS. Surgical decompression with fusion was not associated with increased risk of postsurgery opioid dependence in patients with DS. Overall, opioid dependence was reduced by 4.96% after surgery for DS. Prior opioid dependence is associated with increased risk and increasing age is associated with decreased risk of opioid dependence following surgery for DS.

Evaluation of foraminal cross-sectional area in lumbar spondylolisthesis using kinematic MRI

PURPOSE

To evaluate the kinematic change of cross-sectional area of lumbar intervertebral foramen in degenerative lumbar spondylolisthesis patients using multi-positional MRI.

METHODS

Multi-positional MRI was performed on 31 patients diagnosed with single or multilevel degenerative lumbar spondylolisthesis and 31 control patients without degenerative lumbar spondylolisthesis. Foraminal area (FA) was measured at the lumbar spondylolisthesis level in degenerative lumbar spondylolisthesis group and at L3-4, L4-5, and L5-S1 level in the control group. FA was measured bilaterally in neutral, flexion, and extension positions. The difference in FA between the groups was analyzed using Mann-Whitney U test, and the difference between positions within groups was analyzed using Wilcoxon signed-rank test.

RESULTS

Degenerative lumbar spondylolisthesis group showed significantly smaller FA on both sides and on average in all three positions compared to the control group (p < 0.05 all). From neutral to flexion position, the change in FA was significantly smaller in the degenerative lumbar spondylolisthesis group than in the control group on both sides and on average (p < 0.005 all). In degenerative lumbar spondylolisthesis group, the FA showed no significant change from neutral to flexion, but showed significant change from neutral to extension (p < 0.005 all).

CONCLUSIONS

FA in the degenerative lumbar spondylolisthesis group was smaller than in the control group. There was no difference in FA in degenerative lumbar spondylolisthesis group from neutral to flexion, only from neutral to extension. Patients with degenerative lumbar spondylolisthesis have a higher chance of developing foraminal stenosis.

Lower complication and reoperation rates for laminectomy rather than MI TLIF/other fusions for degenerative lumbar disease/spondylolisthesis: A review

Background:

Utilizing the spine literature, we compared the complication and reoperation rates for laminectomy alone vs. instrumented fusions including minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) for the surgical management of multilevel degenerative lumbar disease with/without degenerative spondylolisthesis (DS).

Methods:

Epstein compared complication and reoperation rates over 2 years for 137 patients undergoing laminectomy alone undergoing 2-3 level (58 patients) and 4-6 level (79 patients) Procedures for lumbar stenosis with/without DS. Results showed no new postoperative neurological deficits, no infections, no surgery for adjacent segment disease (ASD), 4 patients (2.9%) who developed intraoperative cerebrospinal fluid (CSF) fistulas, no readmissions, and just 1 reopereation for a (postoperative day 7). These rates were compared to other literature for lumbar laminectomies vs. fusions (e.g. particularly MI TLIF) addressing pathology comparable to that listed above.

Results:

Some studies in the literature revealed an average 4.8% complication rate for laminectomy alone vs. 8.3% for decompressions/fusion; at 5 postoperative years, reoperation rates were 10.6% vs. 18.4%, respectively. Specifically, the MI TLIF literature complication rates ranged from 7.7% to 23.0% and included up to an 8.3% incidence of wound infections, 6.1% durotomies, 9.7% permanent neurological deficits, and 20.2% incidence of new sensory deficits. Reoperation rates (1.6–6%) for MI TLIF addressed instrumentation failure (2.3%), cage migration (1.26–2.4%), cage extrusions (0.8%), and misplaced screws (1.6%). The learning curve (e.g. number of cases required by a surgeon to become proficient) for MI TLIF was the first 33-44 cases. Furthermore, hospital costs for lumbar fusions were 2.6 fold greater than those for laminectomy alone, with overall neurosurgeon reimbursement quoted in one study as high as $142,075 per year.

Conclusions:

The spinal literature revealed lower complication and reoperation rates for lumbar laminectomy alone vs. higher rates for instrumented fusion, including MI TLIF, for degenerative lumbar disease with/without DS.

Ninety-Day Reimbursements for Primary Single-Level Posterior Lumbar Interbody Fusion From Commercial and Medicare Data

STUDY DESIGN

Retrospective, economic analysis.

OBJECTIVE

To analyze the distribution of 90-day payments for a primary single-level posterior lumbar interbody fusion from Commercial payers and Medicare.

SUMMARY OF BACKGROUND DATA

Episode-based bundled payments aim to align incentives of all health care providers toward the common goal of high quality and economic health care. Understanding the evolving reimbursement models for spine surgery will require knowledge on existing payments, distribution, and variation. Also, it will help identify areas for cost reduction. This is currently not known for a primary single-level posterior lumbar interbody fusion.

METHODS

Administrative claims data were used to study reimbursements from Commercial payers (2007-Q3 2015), Medicare Advantage (2007-Q3 2015), and Medicare (2005-2012) for a primary single-level posterior lumbar interbody fusion. Distribution of payments among various service providers was studied. In addition to descriptive analysis, variation between regions and payers was studied by a one-way analysis of variance and post hoc Tukey test.

RESULTS

Average hospital costs comprise 74.2% to 77% of the total payments, followed by surgeon's fees which accounted for 12.8% to 13.7%. Overall burden of readmissions/revisions was 2.1% to 2.7%, but for the readmitted patient it constitutes 25% to 54% of the 90-day payment. Inpatient surgery had significantly higher facility costs than outpatient surgery (P = 0.02). The average 90-day payment amount was $51,465, $26,234, and $25,501 for Commercial payers, Medicare Advantage, and Medicare, respectively. There was some regional variation, however not consistent among different payers.

CONCLUSION

Hospital costs constitute the majority share of 90-day payments, which can be reduced by performing surgery in the outpatient setting. Reducing hospital costs and readmissions can lower the financial burden associated with this common spine procedure.

LEVEL OF EVIDENCE

3.

Interbody Fusion Techniques in the Surgical Management of Degenerative Lumbar Spondylolisthesis

PURPOSE OF REVIEW

The various lumbar interbody fusion (IBF) techniques and the evidence for their use in the treatment of degenerative lumbar spondylolisthesis (DLS) are described in this review.

RECENT FINDINGS

The existing evidence is mixed regarding the indications for and utility of IBF in DLS, but its use in the setting of pre-operative instability is most strongly supported. Anterior (ALIF), lateral (LLIF), posterior (PLIF), transforaminal (TLIF), and axial (AxiaLIF) lumbar IBF approaches have been described. While the current data are limited, TLIF may be a better option than PLIF in DLS due the increased operative morbidity and peri-operative complications observed with the latter. LLIF also appears superior to PLIF in light of improved radiologic outcomes, fewer intra-operative complications, and potentially greater improvements in disability. The data comparing LLIF to TLIF are less conclusive. No studies specifically comparing ALIF or AxiaLIF to other IBF techniques could be identified. Instability may be the strongest indication for IBF in DLS. When IBF is employed, the authors' preferred technique is TLIF with posterior segmental spinal instrumentation. Further research is needed.

Clinical and radiographic outcomes of bilateral decompression via a unilateral approach with transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis with stenosis

BACKGROUND CONTEXT

Laminectomy with posterior lumbar interbody fusion (PLIF) has been shown to achieve satisfactory clinical outcomes, but it leads to potential adverse consequences associated with extensive disruption of posterior bony and soft tissue structures.

PURPOSE

This study aimed to compare the clinical and radiographic outcomes of bilateral decompression via a unilateral approach (BDUA) with transforaminal lumbar interbody fusion (TLIF) and laminectomy with PLIF in the treatment of degenerative lumbar spondylolisthesis (DLS) with stenosis.

STUDY DESIGN

This is a prospective cohort study.

PATIENT SAMPLE

This study compared 43 patients undergoing BDUA+TLIF and 40 patients undergoing laminectomy+PLIF.

OUTCOME MEASURES

Visual analog scale (VAS) for low back pain and leg pain, Oswestry Disability Index (ODI), and Zurich Claudication Questionnaire (ZCQ) score.

METHODS

The clinical outcomes were assessed, and intraoperative data and complications were collected. Radiographic outcomes included slippage of the vertebra, disc space height, segmental lordosis, and final fusion rate. This study was supported by a grant from The National Natural Science Foundation of China (81572168).

RESULTS

There were significant improvements in clinical and radiographic outcomes from before surgery to 3 months and 2 years after surgery within each group. Analysis of leg pain VAS and ZCQ scores showed no significant differences in improvement between groups at either follow-up. The mean improvements in low back pain VAS and ODI scores were significantly greater in the BDUA+TLIF group than in the laminectomy+PLIF group. No significant difference was found in the final fusion rate at 2-year follow-up. The BDUA+TLIF group had significantly less blood loss, shorter length of postoperative hospital stay, and lower complication rate compared with the laminectomy+PLIF group.

CONCLUSIONS

When compared with the conventional laminectomy+PLIF procedure, the BDUA+TLIF procedure achieves similar and satisfactory effects of decompression and fusion for DLS with stenosis. The BDUA+TLIF procedure appears to be associated with less postoperative low back discomfort and quicker recovery.

Titanium vs. polyetheretherketone (PEEK) interbody fusion: Meta-analysis and review of the literature

Spinal interbody fusion is a standard and accepted method for spinal fusion. Interbody fusion devices include titanium (Ti) and polyetheretherketone (PEEK) cages with distinct biomechanical properties. Titanium and PEEK cages have been evaluated in the cervical and lumbar spine, with conflicting results in bony fusion and subsidence. Using Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, we reviewed the available literature evaluating Ti and PEEK cages to assess subsidence and fusion rates. Six studies were included in the analysis, 3 of which were class IV evidence, 2 were class III, and 1 was class II. A total of 410 patients (Ti-228, PEEK-182) and 587 levels (Ti-327, PEEK-260) were studied. Pooled mean age was 50.8years in the Ti group, and 53.1years in the PEEK group. Anterior cervical discectomy was performed in 4 studies (395 levels) and transforaminal interbody fusion in 2 studies (192 levels). No statistically significant difference was found between groups with fusion (OR 1.16, 95% C.I 0.59-2.89, p=0.686, I²=49.7%) but there was a statistically significant the rate of subsidence with titanium (OR 3.59, 95% C.I 1.28-10.07, p=0.015, I²=56.9%) at last follow-up. Titanium and PEEK cages are associated with a similar rate of fusion, but there is an increased rate of subsidence with titanium cage. Future prospective randomized controlled trials are needed to further evaluate these cages using surgical and patient-reported outcomes.

Spinal Fusion for Pediatric Spondylolisthesis: National Trends, Complications, and Short-Term Outcomes

BACKGROUND

Current surgical management guidelines for pediatric spondylolisthesis (PS) are reliant on data from single-center cohorts.

OBJECTIVE

To analyze national trends and predictors of short-term outcomes in spinal fusion surgery for PS by performing a retrospective cross-sectional analysis of the Kids’ Inpatient Database (KID).

METHODS

The KID (sampled every 3 yr) was queried from 2003 to 2012 to identify all cases (age 5-17) of spinal fusion for PS (n = 2646). We analyzed trends in patient characteristics, surgical management, and short-term outcomes. Both univariate and multivariable analyses were utilized.

RESULTS

The 2646 spinal fusions for PS included posterior-only fusions (86.8%, PSF), anterior lumbar interbody fusions (4.8%, ALIF), and combined anterior and posterior fusions (8.4%, APLF) procedures. The utilization of APLF decreased over time (9.9%-6.4%, P = .023), whereas the number of total spinal fusions and the proportion of PSF and ALIF procedures have not changed significantly. Uptrends in Medicaid insured individuals (1.2%-18.9%), recombinant human bone morphogenetic protein-2 insertion (8.8%-16.6%), decompression (34.7%-42.8%), and mean inflation-adjusted hospital costs ($21 855-$32 085) were identified (all P &lt; .001). In multivariable analysis, Medicaid status (odds ratio [OR] = 1.93, P = .004), teaching hospitals (OR = 1.94, P = .01), decompression (OR = 1.78, P = .004), and the APLF procedure (OR = 2.47, P = .001) increased the likelihood of complication occurrence (all P &lt; .001).

CONCLUSION

The addition of decompression during fusion and the APLF procedure were associated with more in-hospital complications, though this may have been indicative of greater surgical complexity. The utilization of the APLF procedure has decreased significantly, while costs associated with the treatment of PS have increased over time.

A retrospective review comparing two-year patient-reported outcomes, costs, and healthcare resource utilization for TLIF vs. PLF for single-level degenerative spondylolisthesis

PURPOSE

The purpose of this study was to compare patient-reported outcomes (PROs), morbidity, and costs of TLIF vs PLF to determine whether one treatment was superior in the setting of single-level degenerative spondylolisthesis.

METHODS

Patients undergoing TLIF or PLF for single-level spondylolisthesis were included for retrospective analysis. EQ-5D, ODI, SF-12 MCS/PCS, NRS-BP/LP scores were collected at baseline and 24 months after surgery. 90-day post-operative complications, revision surgery rates, and satisfaction scores were also collected. Two-year resource use was multiplied by unit costs based on Medicare payment amounts (direct cost). Patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Total cost was used to assess mean total 2-year cost per QALYs gained after surgery.

RESULTS

62 and 37 patients underwent TLIF and PLF, respectively. Patients in the PLF group were older (p < 0.01). No significant differences were seen in baseline or 24-month PROs between the two groups. There was a significant improvement in all PROs from baseline to 24 months after surgery (p < 0.001). Both groups had similar rates of 90-day complications, revision surgery, satisfaction, and similar gain in QALYs and cost per QALYs gained. There was no significant difference in 24-month direct, indirect, and total cost.

CONCLUSIONS

Overall costs and health care utilization were similar in both the groups. Both TLIF and PLF for single-level degenerative spondylolisthesis provide improvement in disability, pain, quality of life, and general health.

One-Level Lumbar Degenerative Spondylolisthesis and Posterior Approach: Is Transforaminal Lateral Interbody Fusion Mandatory?: A Randomized Controlled Trial With 2-Year Follow-Up

STUDY DESIGN

A monocentric open-label randomized controlled trial (MRCT).

OBJECTIVE

Comparison of clinical and radiological outcomes between isolated instrumented posterior fusion (PLF) and associated instrumented posterior fusion and interbody fusion by transforaminal approach (PLF + TLIF) for patients suffering from one-level lumbar degenerative spondylolisthesis (DS) undergoing surgery.

SUMMARY OF BACKGROUND DATA

DS is a common cause of symptomatic lumbar stenosis. PLF has shown better clinical outcome than decompression with noninstrumented posterolateral fusion. TLIF with interbody cage showed better fusion rate than PLF. There is a need for randomized controlled trials to compare PLF with and without TLIF as to clinical and radiological outcomes.

METHODS

This is a MRCT comparing PLF and TLIF techniques in surgical treatment of DS. Sixty patients were included in a secured database from 2009 to 2011 and randomized into two groups: 30 PLF with posterior pedicle screws and intertransverse autologuous graft, and 30 TLIF in which an interbody fusion by transforaminal approach was added. Data included clinical (pain and disability), surgical (blood loss and operating time), and radiological (alignment and fusion) parameters at baseline and 2-year follow-up. Comparison was made by Student t test and Chi-square test.

RESULTS

There was a significant improvement in each group for pain and disability but no difference between the groups. Radiographic assessment showed better posterolateral fusion rate for TLIF without superiority in segmental lordosis improvement. A case of deformity cascade with spino-pelvic mismatch at baseline was noted in PLF.

CONCLUSION

Posterior decompression and instrumented fusion is an efficient technique that proved its significant clinical benefit in the surgical treatment of DS. TLIF did not show its superiority neither in clinical nor alignment parameters despite a better fusion rate. These results suggest that TLIF is not mandatory in this specific indication. Sagittal alignment analysis by standing full-body images should be considered in DS care.

LEVEL OF EVIDENCE

2.

Degenerative spondylolisthesis: contemporary review of the role of interbody fusion

Degenerative spondylolisthesis is a common presentation, yet the best surgical treatment continues to be a matter of debate. Interbody fusion is one of a number of options, but its exact role remains ill defined. The aim of this study was to provide a contemporary review of the literature to help determine the role, if any, of interbody fusion in the surgical treatment of degenerative spondylolisthesis. A systematic review of the literature since 2005 was performed. Details on study size, patient age, surgical treatments, levels of slip, patient reported outcome measures, radiographic outcomes, complications and selected utility measures were recorded. Studies that compared a cohort treated with interbody fusion and at least one other surgical intervention for comparison were included for review. Only studies examining the effect in degenerative spondylolisthesis were included. Two authors independently reviewed the manuscripts and extracted key data. Thirteen studies were included in the final analysis. A total of 565 underwent interbody fusion and 761 underwent other procedures including decompression alone, interspinous stabilisation and posterolateral fusion with or without instrumentation. Most studies were graded Level III evidence. Heterogeneous reporting of outcomes prevented formal statistical analysis. However, in general, studies reviewed concluded no significant clinical or radiographic difference in outcome between interbody fusion and other treatments. Two small studies suggested interbody fusion is a better option in cases of definite instability. Interbody fusion only provided outcomes as good as instrumented posterolateral fusion. However, most studies were Level III, and hence, we remain limited in defining the exact role of interbody fusion-cases with clear instability appear to be most appropriate. Future work should use agreed-upon common outcome measures and definitions.

Reimbursement Related to a 90-Day Episode of Care for a One or Two-Level Anterior Cervical Discectomy and Fusion

BACKGROUND

A bundled payment represents a single payment for services during an episode of care for a surgical procedure. Anterior cervical discectomy and fusion (ACDF) and associated 90-day costs have been suggested as a bundle amenable to such a payment structure; however, to our knowledge, there are limited available data with regard to costs related to this procedure and subsequent care.

METHODS

The Medicare 5% National Sample Administrative Database was used to catalog clinical and financial data associated with the day of the surgical procedure and the 90-day postoperative period for patients undergoing a one to two-level ACDF procedure from 2005 to 2012. We simultaneously queried the database for total knee replacement as a means to compare the payments and to verify the reliability of our analysis.

RESULTS

A total of 4,506 patients underwent an ACDF procedure for cervical radiculopathy. The total 90-day reimbursement was $69,469,550 or a mean cost per patient (and standard deviation) of $15,417 ± $947 (median, $15,589). As a comparison, the mean reimbursement for patients who had undergone a total knee replacement amounted to $17,451 per patient. The physician reimbursement for ACDF represented 20.42% of the total, with the surgeon receiving 18.07% of the total reimbursement. Revision surgery, readmission, and emergency department reimbursement accounted for 0.71% of the total reimbursement. Reimbursement for rehabilitation services, including physical therapy, skilled nursing facilities, and home care, represented 3.11% of the total reimbursement. There was a significant variation in reimbursement among geographic regions in the United States (p < 0.001), with the highest in the West.

CONCLUSIONS

To our knowledge, this study is the first report on 90-day reimbursement per patient for one to two-level ACDF procedures in a Medicare cohort. Payments varied significantly among geographic locations. Our study provides a reimbursement benchmark for one to two-level ACDF procedures. Clarifying the payments relative to costs will help providers to understand whether a bundled payment for the ACDF procedure is economically viable.

Current Status of Lumbar Interbody Fusion for Degenerative Spondylolisthesis

Instrumented lumbar fusion can provide immediate stability and assist in satisfactory arthrodesis in patients who have pain or instability of the lumbar spine. Lumbar adjunctive fusion with decompression is often a good procedure for surgical management of degenerative spondylolisthesis (DS). Among various lumbar fusion techniques, lumbar interbody fusion (LIF) has an advantage in that it maintains favorable lumbar alignment and provides successful fusion with the added effect of indirect decompression. This technique has been widely used and represents an advancement in spinal instrumentation, although the rationale and optimal type of LIF for DS remains controversial. We evaluated the current status and role of LIF in DS treatment, mainly as a means to augment instrumentation. We addressed the basic concept of LIF, its indications, and various types including minimally invasive techniques. It also has acceptable biomechanical features, and offers reconstruction with ideal lumbar alignment. Postsurgical adverse events related to each LIF technique are also addressed.

Lateral Lumbar Interbody Fusion in Ambulatory Surgery Centers: Patient Selection and Outcome Measures Compared With an Inhospital Cohort

STUDY DESIGN

Comparative analysis.

OBJECTIVE

To evaluate the safety and outcomes of moving lateral lumbar interbody fusion (LLIF) surgeries to an outpatient setting.

SUMMARY OF BACKGROUND DATA

LLIF has been popularized as a less invasive lumbar fusion surgery as an alternative approach to anterior lumbar interbody fusions, posterior lateral interbody fusion, and transforaminal lateral interbody fusion (TLIF). Lumbar fusions have been traditionally performed in a hospital setting because of the potential blood loss, length of surgery, and need for longer recovery. There is a movement to transition spine surgeries to outpatient settings with many benefits afforded by less invasive techniques and technologies.

METHODS

The medical records of 70 consecutive patients with prospectively collected data were retrospectively reviewed. Two cohort groups, inpatients (40 patients) and outpatients (30 patients), were created. Patient demographics, risk factors, and body mass index (BMI) were evaluated to determine inclusion criteria for study.

RESULT

A total of 34 males and 36 females, age range (31-71) average 59.3 ± 2.3 years. Average BMI was 29.6 ± 1.1 kg/m. The most common level operated on being L3-L4 in both groups (63%). Mean preoperative inpatient Oswestry Disability Index (ODI) increased from 48.5 ± 3.0 to 55.5 ± 3.2 compared with outpatient preoperative ODI means reduced from 45.2 ± 5.1 to 39.1 ± 4.6. There was no statistically significant change in VAS scores between groups. There was however significant improvement in outpatient preoperative VAS scores from 7.3 ± 0.5 to 4.1 ± 0.5, P = 0.045.

CONCLUSION

The outcomes of the present study have shown that patients who had LLIF performed in the outpatient setting had statistically significant improvement in ODI scores compared with the inpatient setting (P = 0.013). Fusion was achieved in all patients and there was no evidence of implant failure or subsidence. Complications were transient in both settings. We conclude that outpatient LLIF improves patients' outcomes with similar safety profile as the hospital setting.

LEVEL OF EVIDENCE

3.

National Trends in the Surgical Management of Adult Lumbar Isthmic Spondylolisthesis: 1998 to 2011

STUDY DESIGN

A retrospective review.

OBJECTIVE

Isthmic spondylolisthesis (ISY) is a common orthopedic condition. Our objective was to identify trends in the surgical management of adult ISY in the United States and to evaluate trends in the surgical techniques utilized.

SUMMARY OF BACKGROUND DATA

Various surgical approaches have been described for ISY but preferred trends are not known.

METHODS

Using the Nationwide Inpatient Sample (NIS), 47,132 adult patients (≥ 18 years) with ISY undergoing lumbar spine fusion from 1998 to 2011 were identified. Our primary outcome of interest was the national trend in use of anterior (ASF), posterior (PSF), posterior with interbody (P/TLIF), and combined anterior-posterior fusion (A/PSF) surgeries for ISY patients. Poisson regression, modified Wald's test, and linear and logistic regression analysis with P < 0.05 were used for statistical analysis.

RESULTS

The annual rate of fusion surgeries for ISY increased 4.33 times-from 28.31 surgeries in 1998 to 122.69 surgeries per million US adults per year in 2011. Over the study period, annual rates of ASFs increased 2.65 times (P < 0.001), PSFs increased 1.03 times (P = 0.24), P/TLIFs increased 4.33 times (P < 0.001), and A/PSF increased 2.93 times (P < 0.001). In 2010 to 2011, the complication rate was significantly higher for A/PSF (18.86%, P < 0.001). PSFs had a higher complication rate of 3.61% and P/TLIFs (2.58%). The risk of complications was lower for females, elective admissions, and in hospitals in the South. Mean hospitalization charges adjusted to 2011 dollars were significantly higher for A/PSF ($157,560; 95% CI [95% confidence interval]: 14,480-170,360; P <  .001), followed by P/TLIFs ($103,700; 95% CI: 9840-109,030) and PSFs had lower mean hospitalization charges ($87,420; 95% CI: 8210-92,770).

CONCLUSION

Use of fusion for ISY has significantly increased and interbody fusion has become the most preferred approach over the study period. Hospital charges and complications were highest for combined anterior-posterior fusions.