Anterior lumbar interbody fusion. A minimum 10-year follow-up

Lateral lumbar interbody fusion (LLIF) reduces total lifetime cost compared with posterior lumbar interbody fusion (PLIF) for single-level lumbar spinal fusion surgery: a cost-utility analysis in Thailand

BACKGROUND

Lumbar interbody fusion techniques treat degenerative lumbar diseases effectively. Minimally invasive lateral lumbar interbody fusion (LLIF) decreases soft tissue disruption and accelerates recovery better than standard open posterior lumbar interbody fusion (PLIF). However, the material cost of LLIF is high, especially in Thailand. The cost-effectiveness of LLIF and PLIF in developing countries is unclear. This study compared the cost-utility and clinical outcomes of LLIF and PLIF in Thailand.

METHODS

Data from patients with lumbar spondylosis who underwent single-level LLIF and PLIF between 2014 and 2020 were retrospectively reviewed. Preoperative and 1-year follow-up EuroQol-5D-5L and healthcare costs were collected. A cost-utility analysis with a lifetime time horizon was performed using a societal perspective. Outcomes are reported as the incremental cost-effectiveness ratio (ICER) and quality-adjusted life-year (QALY) gained. A Thai willingness-to-pay threshold of 5003 US dollars (USD) per QALY gained was used.

RESULTS

The 136 enrolled patients had a mean age of 62.26 ± 11.66 years. Fifty-nine patients underwent LLIF, while 77 underwent PLIF. The PLIF group experienced greater estimated blood loss (458.96 vs 167.03 ml; P < 0.001), but the LLIF group had a longer operative time (222.80 vs 194.62 min; P = 0.007). One year postoperatively, the groups' Oswestry Disability Index and EuroQol-Visual Analog Scale scores were improved without statistical significance. The PLIF group had a significantly better utility score than the LLIF group (0.89 vs 0.84; P = 0.023). LLIF's total lifetime cost was less than that of PLIF (30,124 and 33,003 USD). Relative to PLIF, LLIF was not cost-effective according to the Thai willingness-to-pay threshold, with an ICER of 19,359 USD per QALY gained.

CONCLUSIONS

LLIF demonstrated lower total lifetime cost from a societal perspective. Regard to our data, at the 1-year follow-up, the improvement in patient quality of life was less with LLIF than with PLIF. Additionally, economic evaluation modeling based on the context of Thailand showed that LLIF was not cost-effective compared with PLIF. A strategy that facilitates the selection of patients for LLIF is required to optimize patient benefits.

Correlation of mental health with physical function, pain, and disability following anterior lumbar interbody fusion

BACKGROUND

Studies have demonstrated the influence of preoperative mental health on outcomes following spine surgery, but prior literature has not assessed the influence of mental health at time of outcome survey collection.

METHODS

Patients who underwent elective anterior lumbar interbody fusion (ALIF) were identified from a prospective registry. Patient-reported outcomes (PROs) were collected preoperatively and up to 1 year postoperatively. Mental health measures studied included 12-item Short Form (SF-12) Mental Component Score (MCS) and Patient Health Questionnaire-9 (PHQ-9). Patient-Reported Outcome Measurement Information System-Physical Function (PROMIS-PF), SF-12 Physical Component Score (PCS), visual analog scale (VAS) back and leg pain, and Oswestry Disability Index (ODI) were compared to the mental health measures by Pearson's correlation tests.

RESULTS

A total of 166 patients were included. SF-12 MCS demonstrated positive correlation to PROMIS-PF preoperatively (|r|= 0.379) and at 6 weeks (|r|= 0.387) (p ≤ 0.016, all). SF-12 MCS demonstrated negative correlation to VAS back at 6 months (|r|= 0.359), VAS leg at 6 weeks (|r|= 0.475) and 12 weeks (|r|= 0.422), and ODI up to 6 months postoperatively (|r|= 0.417-0.526) (p ≤ 0.037, all). PHQ-9 negatively correlated with PROMIS-PF at all periods studied (|r|= 0.425-0.587) and SF-12 PCS up to 6 months postoperatively (|r|= 0.367-0.642) (p ≤ 0.016, all). PHQ-9 positively correlated to VAS back at 6 weeks (|r|= 0.408) and 6 months (|r|= 0.411), VAS leg at 6 weeks (|r|= 0.344), and ODI up to 6 months postoperatively (|r|= 0.321-0.669) (p ≤ 0.034, all).

CONCLUSION

Inferior mental health correlated with inferior pain, function, and disability scores at one or more periods postoperatively. This finding was most consistent for correlation between mental health scores and disability. Optimization of mental health may positively influence outcomes, especially regarding disability, following ALIF.

Biomechanical analysis of stand-alone lumbar interbody cages versus 360° constructs: an in vitro and finite element investigation

OBJECTIVE

Low fusion rates and cage subsidence are limitations of lumbar fixation with stand-alone interbody cages. Various approaches to interbody cage placement exist, yet the need for supplemental posterior fixation is not clear from clinical studies. Therefore, as prospective clinical studies are lacking, a comparison of segmental kinematics, cage properties, and load sharing on vertebral endplates is needed. This laboratory investigation evaluates the mechanical stability and biomechanical properties of various interbody fixation techniques by performing cadaveric and finite element (FE) modeling studies.

METHODS

An in vitro experiment using 7 fresh-frozen human cadavers was designed to test intact spines with 1) stand-alone lateral interbody cage constructs (lateral interbody fusion, LIF) and 2) LIF supplemented with posterior pedicle screw-rod fixation (360° constructs). FE and kinematic data were used to validate a ligamentous FE model of the lumbopelvic spine. The validated model was then used to evaluate the stability of stand-alone LIF, transforaminal lumbar interbody fusion (TLIF), and anterior lumbar interbody fusion (ALIF) cages with and without supplemental posterior fixation at the L4-5 level. The FE models of intact and instrumented cases were subjected to a 400-N compressive preload followed by an 8-Nm bending moment to simulate physiological flexion, extension, bending, and axial rotation. Segmental kinematics and load sharing at the inferior endplate were compared.

RESULTS

The FE kinematic predictions were consistent with cadaveric data. The range of motion (ROM) in LIF was significantly lower than intact spines for both stand-alone and 360° constructs. The calculated reduction in motion with respect to intact spines for stand-alone constructs ranged from 43% to 66% for TLIF, 67%-82% for LIF, and 69%-86% for ALIF in flexion, extension, lateral bending, and axial rotation. In flexion and extension, the maximum reduction in motion was 70% for ALIF versus 81% in LIF for stand-alone cases. When supplemented with posterior fixation, the corresponding reduction in ROM was 76%-87% for TLIF, 86%-91% for LIF, and 90%-92% for ALIF. The addition of posterior instrumentation resulted in a significant reduction in peak stress at the superior endplate of the inferior segment in all scenarios.

CONCLUSIONS

Stand-alone ALIF and LIF cages are most effective in providing stability in lateral bending and axial rotation and less so in flexion and extension. Supplemental posterior instrumentation improves stability for all interbody techniques. Comparative clinical data are needed to further define the indications for stand-alone cages in lumbar fusion surgery.

Outcomes of anterior vs. posterior approach to single-level lumbar spinal fusion with interbody device: An analysis of the nationwide inpatient sample

BACKGROUND

Interbody devices have revolutionized lumbar spinal fusion surgery by improving mechanical stability and maximizing fusion potential. Several approaches for interbody fusion exist with two of the most common being anterior lumbar interbody fusion (ALIF) and posterior lumbar interbody fusion (PLIF). This study aims to compare patient data, hospital outcomes, and post-operative complications between an anterior vs. posterior approach to lumbar interbody fusion.

METHODS

This retrospective cohort study utilized the Nationwide Inpatient Sample (NIS) and International Classification of Diseases, 10th edition (ICD10) codes to identify patients (18 +) from 2016 to 2018 who underwent lumbar interbody fusion under an anterior or posterior approach. Patients missing identifiers were excluded from this study. Patients were further investigated by demographic data and the presence of comorbidities. Hospital outcome data was investigated by length of stay (LOS), total hospital charges, mortality, and post-operative complications.

RESULTS

373,585 patients were included in this study. 257,975 (69%) underwent fusion via a posterior approach, and 115,610 (31%) via an anterior approach. Patients undergoing posterior approach were found to have a greater number of comorbidities than anterior (3.5 vs. 2, respectively, p = <0.001). The posterior approach was associated with decreased LOS (3.59 vs 4.19 days, p = <0.0001) and decreased total hospital charges ($141,700 vs $211,015, p = <0.0001). A posterior approach was found to have lower rates of post-operative complications. For the anterior approach cohort, tobacco dependence (OR=1.31 [1.20-1.42, p = <0.001], diabetes (OR=2.41 [2.33-2.49, p = <0.001], and osteoporosis (OR=1.42 [1.30-1.54, p = <0.001] were found to be significant independent predictors of post-operative pseudoarthrosis. Obesity (OR=1.28 [1.14-1.42, p = <0.001], tobacco dependence (OR=1.48 [1.40-1.56, p = <0.001], diabetes (OR=2.21 [2.10-2.32, p = <0.001], congestive heart failure (OR=1.20 [1.01-1.39, p = 0.04], and osteoporosis (OR=1.65 [1.55-1.75, p = <0.001], were found to be independent predictors of post-operative pseudoarthrosis in the posterior cohort.

CONCLUSIONS

Patients who underwent the anterior approach suffered from increased hospital charges, length of stay, and increased risk of post-operative complications including mortality, wound dehiscence, hematoma/seroma, and pseudoarthrosis. Comorbid disease plays a significant role in the outcome of successful fusion with variable effect depending on the surgical approach. Increasing due diligence in patient selection should be considered when choosing an approach in pre-operative planning.

Risk factors for cage subsidence and clinical outcomes after transforaminal and posterior lumbar interbody fusion

BACKGROUND

Cage subsidence is a very common complication after lumbar interbody fusion. It may compromise vertebral interbody fusion through progressive spinal deformity and consequently cause compression of neural elements. Clinical relevance remains, however, unclear, with few studies on this subject and even less information regarding its correlation with clinical findings. The aim of this study was to identify risk factors for cage subsidence and clinical evaluation after transforaminal (TLIF) and posterior (PLIF) lumbar interbody fusion.

METHODS

A retrospective study in patients submitted to TLIF and PLIF between 2008 and 2017 was conducted.

RESULTS

A total of 165 patients were included (123 TLIF and 42 PLIF). Univariate analysis showed an increased risk of cage subsidence in spondylolisthesis comparing with degenerative disk disease (p = 0.007). A higher preoperative lumbar lordosis angle (p = 0.014) and cage placement in L2-L3 (p = 0.012) were associated with higher risk of subsidence. The posterior cage positioning on vertebral endplate was associated with a higher risk of subsidence (p = 0.028) and significant subsidence (p = 0.005), defined as cage migration > 50% of cage height. PLIF presented a higher risk when comparing with TLIF (p = 0.024). Hounsfield unit (HU) values < 135 (OR6; 95% CI [1.95-34]) and posterior positioning (OR7; 95% CI [1.7-27.3]) were independent risk factors for cage subsidence and significant subsidence, respectively, in multivariate analysis. There was a tendency for significant subsidence in degrees ≥ 2 of Meyerding spondylolisthesis (OR4; 95% CI [0.85-21.5]). Significant cage subsidence was not associated with worse clinical results. Other analyzed factors, such as age (p = 0.008), low bone mineral density (BMD) (p = 0.029) and type of surgery (TLIF) (p = 0.004), were associated with worse results.

CONCLUSION

The present study shows that lower BMD and posterior cage positioning are relevant risk factors for lumbar cage subsidence. Low BMD is also a predictor of poor clinical results, so it must be properly evaluated and considered, through HU values measurement in CT scan, a feasible and reliable tool in perioperative planning.

Does Workers' Compensation Status Affect Outcomes after Lumbar Spine Surgery? A Systematic Review and Meta-Analysis

Low back pain (LBP) is currently the leading cause of disability worldwide and the most common reason for workers’ compensation (WC) claims. Studies have demonstrated that receiving WC is associated with a negative prognosis following treatment for a vast range of health conditions. However, the impact of WC on outcomes after spine surgery is still controversial. The aim of this meta-analysis was to systematically review the literature and analyze the impact of compensation status on outcomes after lumbar spine surgery. A systematic search was performed on Medline, Scopus, CINAHL, EMBASE and CENTRAL databases. The review included studies of patients undergoing lumbar spine surgery in which compensation status was reported. Methodological quality was assessed through ROBINS-I and quality of evidence was estimated using the GRADE rating. A total of 26 studies with a total of 2668 patients were included in the analysis. WC patients had higher post-operative pain and disability, as well as lower satisfaction after surgery when compared to those without WC. Furthermore, WC patients demonstrated to have a delayed return to work. According to our results, compensation status is associated with poor outcomes after lumbar spine surgery. Contextualizing post-operative outcomes in clinical and work-related domains helps understand the multifactorial nature of the phenomenon.

Clinical Evaluation of Microendoscopy-Assisted Oblique Lateral Interbody Fusion

Background and objectives: Oblique Lateral Interbody Fusion (OLIF) is a widely performed, minimally invasive technique to achieve lumbar lateral interbody fusion. However, some complications can arise due to constraints posed by the limited surgical space and visual field. The purpose of this study was to assess the short-term postoperative clinical outcomes of microendoscopy-assisted OLIF (ME-OLIF) compared to conventional OLIF. Materials and Methods: We retrospectively investigated 75 consecutive patients who underwent OLIF or ME-OLIF. The age, sex, diagnosis, and number of fused levels were obtained from medical records. Operation time, estimated blood loss (EBL), and intraoperative complications were also collected. Operation time and EBL were only measured per level required for the lateral procedure, excluding the posterior fixation surgery. The primary outcome measure was assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The secondary outcome measure was assessed using the Oswestry Disability Index (ODI) and the European Quality of Life–5 Dimensions (EQ-5D), measured preoperatively and 1-year postoperatively. Results: This case series consisted of 14 patients in the OLIF group and 61 patients in the ME-OLIF group. There was no significant difference between the two groups in terms of the mean operative time and EBL (p = 0.90 and p = 0.50, respectively). The perioperative complication rate was 21.4% in the OLIF group and 21.3% in the ME-OLIF group (p = 0.99). In both groups, the postoperative JOABPEQ, EQ-5D, and ODI scores improved significantly (p < 0.001). Conclusions: Although there was no significant difference in clinical results between the two surgical methods, the results suggest that both are safe surgical methods and that microendoscopy-assisted OLIF could serve as a potential alternative to the conventional OLIF procedure.

Development of a Multivariate Prediction Model for Successful Oswestry Disability Index Changes in L5/S1 Anterior Lumbar Interbody Fusion for Degenerative Disc Disease

OBJECTIVE

Lower back pain associated with degenerative disc disease (DDD) is a leading cause of disability worldwide. Anterior lumbar interbody fusion (ALIF) has been shown to be effective for treating refractory DDD, but it remains unclear which patients may benefit most from the procedure. This study aims to develop a predictive model for clinical success in L5/S1 ALIF for DDD.

METHODS

A retrospective cohort study of 68 patients with refractory DDD who underwent L5/S1 ALIF was performed. Clinical success was defined as an improvement in Oswestry Disability Index (ODI) of 20 points postoperatively. Exploratory analyses were performed on 16 preoperative clinical and radiographic parameters, followed by a multivariate logistic regression. Evaluation of the predictive model was performed.

RESULTS

After exploratory analyses, 4 parameters were suitable for inclusion in the multivariate model. Workers' compensation status (odds ratio [OR], 0.02; 95% confidence interval [CI], 0.001-0.262; P = 0.004) and preoperative ODI (OR, 1.13; 95% CI, 1.05-1.23; P = 0.002) were statistically significant parameters. Furthermore, posterior disc height and disc depth contributed significantly to the model variance (OR, 0.69, 95% CI, 0.44-1.09 and OR, 0.97, 95% CI, 0.81-1.15, respectively). The model had a sensitivity of 81.5%, specificity of 83.3%, C-statistic of 0.921, and a calibration plot similar to the 45° reference line.

CONCLUSIONS

This analysis confirms workers' compensation and low preoperative ODI as risk factors for successful L5/S1 ALIF performed for DDD. It also identifies novel prognostic factors, namely posterior disc height and disc depth. This model can aid in patient counseling and selection in the management of L5/S1 DDD.

The rate of fusion for stand-alone anterior lumbar interbody fusion: a systematic review

BACKGROUND

Anterior lumbar interbody fusion (ALIF) has been used for treatment of a variety of spinal conditions including degenerative disc disorders and low-grade spondylolisthesis. Expected fusion rate of stand-alone ALIF constructs is currently unclear. The aim of this study was to examine the fusion rate for ALIF without supplemental posterior fusion or instrumentation (stand-alone ALIF).

METHODS

We queried the MEDLINE, COCHRANE, and EMBASE databases for all literature related to spine fusion rates using a stand-alone ALIF procedure with a publication cutoff date of July 19, 2018. Supplementary combinations of search terms included spine, fusion, fixation, rate(s), and arthrodesis. ALIF surgery was considered stand-alone when not paired with supplemental posterior fusion or posterior spinal instrumentation. Nonhuman and non-English publications were excluded. Cohort fusion rate differences were calculated using Student t test with significance assigned if p value was less than .05.

RESULTS

Title and abstract level review required assessing 840 unique publications. Across the 55 studies that met the inclusion criteria of this systematic review, 5,517 patients and 6,303 vertebral levels were fused. The overall weighted average patient fusion rate following stand-alone ALIF was 88.2% (range: 16.6%-100%). In the 31 studies with at least 50 subjects, the weighted average fusion rate following stand-alone ALIF was 88.6% (range: 57.5%-99.0%). Use of anterior fixation plate devices yielded a fusion rate of 94.2%. Newer zero-profile interbody implants had a fusion rate of 89.2%. Fusion rates were lower in studies with 50% or more subjects having positive smoking and worker's compensation status, however these results were found to be statistically insignificant (p>.05). Fusion rate for subjects in the eight rhBMP-2 study groups was 94.4% (n=889) compared with 84.8% (n=3,102) in 38 study groups without rhBMP-2 used.

CONCLUSIONS

Based on the available data, stand-alone ALIF procedures yield high fusion rates overall. Fusion failure and pseudoarthrosis rates are higher in study populations involving a high percentage of smokers or positive workers compensation status. Allograft utilization does not significantly improve fusion rate when compared with autograft in stand-alone ALIF constructs.

Iatrogenic Bowel Injury Following Minimally Invasive Lateral Approach to the Lumbar Spine: A Retrospective Analysis of 3 Cases

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Anterior approaches are often used during lumbar interbody fusion procedures. Visceral injuries (bowel injuries) are rare but represent a primary risk during anterior approaches to the lumbar spine. Left untreated, these injuries can result in significant complications. The aim of this study was to investigate the presentation and management of bowel injury cases following anterior approaches to the lumbar spine to raise the surgeon's awareness of this rare complication.

METHODS

All direct anterior, oblique anterior, and transpsoas lumbar interbody fusion surgeries performed at our institution between 2012 and 2016 were analyzed retrospectively. Charts were screened for cases requiring return to the operating room owing to a suspected bowel injury and details of the case were extracted for illustrative purposes.

RESULTS

A total of 775 anterior lumbar surgeries were conducted at a single tertiary care institution between July 2012 and June 2017. A total of 590 transpsoas lumbar interbody fusion (TPIF) surgeries were performed. Four patients, each having undergone TPIF, were suspected of bowel injury and underwent an exploratory laparotomy. At surgery, 3 patients were confirmed to have a bowel injury, giving a procedure-specific incidence of 0.51% and overall incidence of 0.39%. Among the 3 confirmed bowel injury cases, average delay between surgery and visceral injury diagnosis was 4.7 days (range 3-7 days).

CONCLUSIONS

We noted abdominal pain, distention, and fever as the most common findings in the setting of a visceral injury. A high index of suspicion and computed tomography imaging remain critical for identifying postoperative bowel injuries.

Comparative Radiographic Outcomes of Lateral and Posterior Lumbar Interbody Fusion in the Treatment of Degenerative Lumbar Kyphosis

STUDY DESIGN

Retrospective case-control study.

PURPOSE

To compare surgical invasiveness and radiological outcomes between posterior lumbar interbody fusion (PLIF) and lateral lumbar interbody fusion (LLIF) for degenerative lumbar kyphosis.

OVERVIEW OF LITERATURE

LLIF is a minimally invasive interbody fusion technique; however, few reports compared the clinical outcomes of conventional PLIF and LLIF for degenerative lumbar kyphosis.

METHODS

Radiographic data for patients who have undergone lumbar interbody fusion (≥3 levels) using PLIF or LLIF for degenerative lumbar kyphosis (lumbar lordosis [LL] <20°) were retrospectively examined. The following radiographic parameters were retrospectively evaluated preoperatively and 2 years postoperatively: segmental lordotic angle, LL, pelvic tilt (PT), pelvic incidence (PI), C7 sagittal vertical axis, and T1 pelvic angle.

RESULTS

Nineteen consecutive cases with PLIF and 27 cases with LLIF were included. There were no significant differences in patients' backgrounds or preoperative radiographic parameters between the PLIF and the LLIF groups. The mean fusion level was 5.5±2.5 levels and 5.8±2.5 levels in the PLIF and LLIF groups, respectively (p=0.69). Although there was no significant difference in surgical times (p=0.58), the estimated blood loss was significantly greater in the PLIF group (p<0.001). Two years postoperatively, comparing the PLIF and LLIF groups, the segmental lordotic angle achieved (7.4°±7.6° and 10.6°±9.4°, respectively; p=0.03), LL (27.8°±13.9° and 39.2°±12.7°, respectively; p=0.006), PI-LL (19.8°±14.8° and 3.1°±17.5°, respectively; p=0.002), and PT (22.6°±7.1° and 14.2°±13.9°, respectively; p=0.02) were significantly better in the LLIF group.

CONCLUSIONS

LLIF provided significantly better sagittal alignment restoration in the context of degenerative lumbar kyphosis, with less blood loss.

Retroperitoneal Extrapleural Approach for Corpectomy of the First Lumbar Vertebra : Technique and Outcome

Objective

Corpectomy of the first lumbar vertebra (L1) for the management of different L1 pathologies can be performed using either an anterior or posterior approach. The aim of this study was to evaluate the usefulness of a retroperitoneal extrapleural approach through the twelfth rib for performing L1 corpectomy.

Methods

Thirty consecutive patients underwent L1 corpectomy between 2010 and 2016. The retroperitoneal extrapleural approach through the 12th rib was used in all cases to perform single-stage anterior L1 corpectomy, reconstruction and anterior instrumentation, except for in two recurrent cases in which posterior fixation was added. Visual analogue scale (VAS) was used for pain intensity measurement and ASIA impairment scale for neurological assessment. The mean follow-up period was 14.5 months.

Results

The sample included 18 males and 12 females, and the mean age was 40.3 years. Twenty patients (67%) had sensory or motor deficits before the surgery. The pathologies encountered included traumatic fracture in 12 cases, osteoporotic fracture in four cases, tumor in eight cases and spinal infection in the remaining six cases. The surgeries were performed from the left side, except in two cases. There was significant improvement of back pain and radicular pain as recorded by VAS. One patient exhibited postoperative neurological deterioration due to bone graft dislodgement. All patients with deficits at least partially improved after the surgery. During the follow-up, no hardware failures or losses of correction were detected.

Conclusion

The retroperitoneal extrapleural approach through the 12th rib is a feasible approach for L1 corpectomy that can combine adequate decompression of the dural sac with effective biomechanical restoration of the compromised anterior load-bearing column. It is associated with less pulmonary complication, no need for chest tube, no abdominal distention and rapid recovery compared with other approaches.

Heterogeneity of Reporting Outcomes in the Spine Surgery Literature

STUDY DESIGN

Review of spine surgery literature between 2005 and 2014 to assess the reporting of patient outcomes by determining the variability of use of patient outcomes metrics in the following categories: pain and disability, patient satisfaction, readmission, and depression.

OBJECTIVE

Expose the heterogeneity of outcomes reporting and discuss current initiatives to create more homogenous outcomes databases.

SUMMARY OF BACKGROUND DATA

There has been a recent focus on the reporting of quality metrics associated with spine surgery outcomes. However, little consensus exists on the optimal metrics that should be used to measure spine surgery outcomes.

MATERIALS AND METHODS

A PubMed search of all spine surgery manuscripts from January 2005 through December 2014 was performed. Linear regression analyses were performed on individual metrics as well as outcomes categories as a fraction of total papers reviewing surgical outcomes.

RESULTS

Outcomes reporting has increased significantly between January 1, 2005 and December 31, 2014 [175/2871 (6.1%) vs. 764/5603 (13.6%), respectively; P<0.001; R=98.1%]. For the category of pain and disability reporting, Visual Analog Score demonstrated a statistically significant decrease in use from 2005 through 2014 [56/76 (73.7%) vs. 300/520 (57.7%), respectively; P<0.001], whereas Oswestry Disability Index increased significantly in use [19/76 (25.0%) vs. 182/520 (35.0%), respectively; P<0.001]. For quality of life, EuroQOL-5 Dimensions increased significantly in use between 2005 and 2014 [4/23 (17.4%) vs. 30/87 (34.5%), respectively; P<0.01]. In contrast, use of 36 Item Short Form Survey significantly decreased [19/23 (82.6%) vs. 57/87 (65.5%), respectively; P<0.01]. For depression, only the Zung Depression Scale underwent a significant increase in usage between 2005 and 2014 [0/0 (0%) vs. 7/13 (53.8%), respectively; P<0.01].

CONCLUSIONS

Although spine surgery outcome reporting has increased significantly over the past 10 years, there remains considerable heterogeneity in regards to individual outcomes metrics utilized. This heterogeneity makes it difficult to compare outcomes across studies and to accurately extrapolate outcomes to clinical practice.

Understanding Retroperitoneal Anatomy for Lateral Approach Spine Surgery

Lateral approach spine surgery provides effective interbody stabilization, and correction and indirect neural decompression with minimal-incision and less invasive surgery compared with conventional open anterior lumbar fusion. It may also avoid the trauma to paraspinal muscles or facet joints found with transforaminal lumbar interbody fusion and posterior lumbar interbody fusion. However, because lateral approach surgery is fundamentally retroperitoneal approach surgery, it carries potential risk to intra- and retroperitoneal structures, as seen in a conventional open anterior approach. There is an innovative lateral approach technique that reveals different anatomical views; however, it requires reconsideration of the traditional surgical anatomy in more detail than a traditional open anterior approach. The retroperitoneum is the compartmentalized space bounded anteriorly by the posterior parietal peritoneum and posteriorly by the transversalis fascia. The retroperitoneum is divided into three compartments by fascial planes: anterior and posterior pararenal spaces and the perirenal space. Lateral approach surgery requires mobilization of the peritoneum and its content and accurate exposure to the posterior pararenal space. The posterior pararenal space is confined anteriorly by the posterior renal fascia, anteromedially by the lateroconal fascia, and posteriorly by the transversalis fascia. The posterior renal fascia, the lateroconal fascia or the peritoneum should be detached from the transversalis fascia and the psoas fascia to allow exposure to the posterior pararenal space. The posterior pararenal space, however, does not allow a clear view and identification of these fasciae as this relationship is variable and the medial extent of the posterior pararenal space varies among patients. Correct anatomical recognition of the retroperitoneum is essential to success in lateral approach surgery. Spine surgeons must be aware that the retroperitoneal membrane and fascia is multilayered and more complex than is commonly understood. Preoperative abdominal images would facilitate more efficient surgical considerations of retroperitoneal membrane and fascia in lateral approach surgery.

A Comparison of Anterior and Posterior Lumbar Interbody Fusions: Complications, Readmissions, Discharge Dispositions, and Costs

STUDY DESIGN

Retrospective database review.

OBJECTIVE

To understand medical complication rates, readmission rates, costs, and discharge dispositions in anterior lumbar interbody fusion (ALIFs) versus transforaminal lumbar interbody fusions (TLIFs)/posterior lumbar interbody fusions (PLIFs) for lumbar degenerative disease.

SUMMARY OF BACKGROUND DATA

Indications for ALIFs versus PLIFs can vary, though benefits of anterior approach surgery include full access to the anterior column and ability to place fusion devices.

METHODS

The PearlDiver Database of Medicare records was utilized for this retrospective database review. A study group consisting solely of ALIF procedure patients was selected for. Similarly, a TLIF/PLIF group was selected for. Both groups were queried for comorbidities, 30 and 90-day complication and readmission rates. Additionally, discharge dispositions, and in-hospital/30-day/90-day Medicare reimbursements were determined.

RESULTS

At both 30 and 90 days postoperatively odds of ileus, wound infection, and lower extremity deep venous thrombosis were significantly increased in the ALIF. However, unadjusted rates and adjusted odds of transfusion or dural tear were significantly decreased in the ALIF patients. Odds of 30-day readmission were 4 times higher in ALIF patients. Additionally, 30 and 90-day total costs of care in ALIF patients were significantly increased by approximately $4800 and $5800 respectively, as compared with patients undergoing TLIF/PLIF.

CONCLUSION

Despite higher initial routine discharge rates, readmissions and costs of postoperative care were significantly increased in ALIF procedures. It is necessary to evaluate etiology of degenerative pathology as ALIFs are successful solutions to anterior translational instability and anterior disc slippage, but may not have the best long-term outcomes and may not be cost-effective compared with a TLIF/PLIF. In light of our data, it is important to assess the risks and benefits of the varying approaches, and the necessity to access the anterior column, when deciding on surgical technique to treat lumbar degenerative pathology.

LEVEL OF EVIDENCE

4.

Adult Spinal Deformity: National Trends in the Presentation, Treatment, and Perioperative Outcomes From 2003 to 2010

STUDY DESIGN

Retrospective review of a prospective database.

OBJECTIVES

To investigate adult spinal deformity (ASD) surgery outcome trends on a nationwide scale using the Nationwide Inpatient Sample (NIS) from 2003 to 2010.

METHODS

ASD patients ≥25 years from 2003 to 2010 in the NIS undergoing anterior, posterior, or combined surgical approaches were included. Fractures, 9+ levels fused, or any cancer were excluded. Patient demographics, hospital data, and procedure-related complications were evaluated. Yearly trends were analyzed using univariate analysis and linear regression modeling.

RESULTS

Of 10,966 discharges, 1,952 were anterior, 6,524 were posterior, and 1,106 were combined. The total surgical ASD volume increased by 112.5% (p = .029), and both the average patient age (p < .001) and number of patients >65 years old significantly increased from 2003 to 2010 (p = .009). Anterior approach case volume decreased by 13.7% (p = .019), whereas that of combined increased by 22.7% (p = .047). Posterior case volume increased by 38.9% from 2003 to 2010, though insignificantly (p = .084). Total hospital charges for all approaches increased over the interval (p < .001). Total length of stay for all approaches decreased over the time interval (p < .005). Although the overall morbidity for all approaches increased by 22.7% (p < .001), mortality did not change (p = .817). The most common morbidities in 2003 were hemorrhagic anemia, accidental cut, puncture, perforation, or laceration during a procedure, and device-related complications, which persisted in 2010 with the exception of increased acute respiratory distress syndrome and pulmonary-related complications.

CONCLUSIONS

For ASD surgery from 2003 to 2010, the volume of anterior approaches decreased, whereas posterior procedures did not change, and combined approaches increased. Total hospital charges increased for all considered procedures, length of hospital stay decreased, whereas operative patients were increasingly elderly, and more procedures were observed for patients >65 years old. For all approaches, morbidity increased whereas mortality did not change. Future study is required to develop methods to reduce morbidity and costs, thereby optimizing patient outcomes.

Worker's Compensation Status and Outcomes Following Anterior Lumbar Interbody Fusion: Prospective Observational Study

BACKGROUND

Anterior lumbar-interbody fusion (ALIF) is a commonly performed procedure for degenerative spinal disorders with reasonable clinical and safety outcomes, although there is limited evidence regarding the impact of ALIF in patients receiving worker's compensation (WC) compared with those without. The aim of our study is to identify whether WC status affects the clinical outcome and rates of complication following ALIF surgery in a prospective cohort.

METHODS

We followed prospectively 114 consecutive patients undergoing ALIF surgery from 2012-2014. Patients were categorized into 2 groups: those with worker's compensation (WC) (n = 24) and those without (n = 90). Patients were evaluated preoperative and postoperatively. Outcome measures included Short Form-12 (SF-12), Oswestry Disability Index (ODI), surgical complications, and subsidence.

RESULTS

In terms of baseline traits, the WC group had a significantly higher proportion of class III/IV obesity patients, who were younger (46.3 vs. 60.2 years) compared with non-WC. There were no significant differences in fusion rates or preoperative or postoperative disk height. No significant differences were found for hospital stay, blood loss, or operation duration. Similar rates of complications were found between WC versus non-WC cohorts. No significant difference was noted in clinical improvement between the 2 cohorts with SF-12 PCS, SF-12 MCS, or ODI (P = 0.232). No significant difference was found in the proportion of patients achieving minimal clinically important difference for SF-12 PCS/MCS or ODI.

CONCLUSIONS

In our prospective cohort, there were no significant differences found between WC versus non-WC patients in terms of fusion rates, complications, clinical outcomes, or proportion of patients achieving minimal clinically important difference.

An Outcome Measure of Functionality and Pain in Patients with Low Back Disorder: A Validation Study of the Iranian version of Low Back Outcome Score

Study Design

Cross-sectional study.

Purpose

This study aimed to cross-culturally translate and validate the low back outcome score (LBOS) in Iran.

Overview of Literature

Lumbar disc hernia (LDH) is the most common diagnoses of low back pain and imposes a heavy burden on both individual and society. Instruments measuring patient reported outcomes should satisfy cetain psychometric properties.

Methods

The translation and cross-cultural adaptation of the original questionnaire was performed using Beaton's guideline. A total of 163 patients with LDH were asked to respond to the questionnaire at three points in time: preoperative and twice within 1-week interval after surgery assessments. The Oswestry disabilty index (ODI) was also completed. The internal consistency, test-retest, convergent validity, and responsiveness to change were assessed. Responsiveness to change also was assessed comparing patients' pre- and postoperative scores.

Results

The mean age of the cohort was 49.8 years (standard deviation=10.1). The Cronbach's alpha coefficients for the LBOS at preoperative and postoperative assessments ranged from 0.77 to 0.79, indicating good internal consistency. Test-retest reliability as performed by intraclass correlation coefficient was found to be 0.82 (0.62–0.91). The instrument discriminated well between sub-groups of patients who differed in the Finneson-Cooper score. The ODI correlated strongly with the LBOS score, lending support to its good convergent validity (r=––0.83; p<0.001). Further analysis also indicated that the questionnaire was responsive to change (p<0.001).

Conclusions

The Iranian version of LBOS performed well and the findings suggest that it is a valid measure of back pain treatment evaluation among LDH patients.

Operative Management of Lumbar Degenerative Disc Disease

Lumbar degenerative disc disease is extremely common. Current evidence supports surgery in carefully selected patients who have failed non-operative treatment and do not exhibit any substantial psychosocial overlay. Fusion surgery employing the correct grafting and stabilization techniques has long-term results demonstrating successful clinical outcomes. However, the best approach for fusion remains debatable. There is some evidence supporting the more complex, technically demanding and higher risk interbody fusion techniques for the younger, active patients or patients with a higher risk of non-union. Lumbar disc arthroplasty and hybrid techniques are still relatively novel procedures despite promising short-term and mid-term outcomes. Long-term studies demonstrating superiority over fusion are required before these techniques may be recommended to replace fusion as the gold standard. Novel stem cell approaches combined with tissue engineering therapies continue to be developed in expectation of improving clinical outcomes. Results with appropriate follow-up are not yet available to indicate if such techniques are safe, cost-effective and reliable in the long-term.

What Is the Clinical Relevance of Radiographic Nonunion After Single-Level Lumbar Interbody Arthrodesis in Degenerative Disc Disease?: A Meta-Analysis of the YODA Project Database

STUDY DESIGN

Meta-analysis of 4 randomized controlled clinical trials (RCTs).

OBJECTIVE

The aim of the study was to determine if patients with degenerative disc disease who achieve radiographic fusion after single-level lumbar interbody arthrodesis have better clinical outcomes than patients with radiographic pseudarthrosis at 12 and 24 months postoperative.

SUMMARY OF BACKGROUND DATA

The clinical relevance of successful fusion after lumbar arthrodesis with recombinant human bone morphogenetic protein-2 or iliac crest bone autograft has recently been questioned in the literature.

METHODS

Individual patient-level data of 4 RCTs were obtained from the Yale University Open Data Access Project project and analyzed. Clinical outcomes (Oswestry Disability Index [ODI]; Numeric Rating Scales [NRSs] for back and leg pain) were compared between patients with radiographically confirmed fusion and those with radiographic nonunion 1 and 2 years postoperative. The results of each study were first analyzed separately, and then were pooled by meta-analysis. The GRADE approach was applied to evaluate the level of evidence.

RESULTS

A total of 496 patients with clinical and radiographic data at 1- and 2-year follow-ups were identified. Of these, 5.5% (95% confidence interval: 3.7; 8.3) had radiographic nonunion which did not require reoperation. Patients with fusion had better improvements in ODI (P < 0.001) and NRS back pain scores (P < 0.001). The overall percentage of fused patients with ODI and NRS back pain scores that exceeded the criteria for minimal clinically important differences was also significantly higher than that of patients with nonunion (ODI, odds ratio [OR] = 2.7, P = 0.019; NRS back pain, OR = 3.5, P = 0.033). The predictive values of fusion for clinical outcomes, however, were poor, with low specificity and low negative predictive values.

CONCLUSION

The presence of radiographic fusion is clinically significant, as patients with fusion had better clinical outcomes at 1 and 2 years postoperative than those with nonunion; however, patient-centered clinical outcomes should also be taken into consideration as independent, complimentary variables when assessing treatment success.

Association between compensation status and outcomes in spine surgery: a meta-analysis of 31 studies

BACKGROUND CONTEXT

Numerous studies have demonstrated poorer outcomes in patients with Workers' compensation (WC) when compared with those without WC following treatment of various of health conditions, including spine disorders. It is thus important to consider compensation status when assessing treatment outcomes in spine surgery. However, reported strengths of association have varied significantly (1.31-7.22).

PURPOSE

The objective of this study was to evaluate the association of unsatisfactory outcomes on compensation status in spine surgery patients.

STUDY DESIGN/SETTING

A meta-analysis was performed.

PATIENT SAMPLE

Patient sample is not applicable in this study.

OUTCOME MEASURE

Demographics, type of surgery, country, follow-up time, patient satisfaction, return to work and non-union events were the outcome measures.

METHODS

Both prospective and retrospective studies that compared outcomes between compensated and non-compensated patients in spine surgery were included. Two independent investigators extracted outcome data. The meta-analysis was performed using Revman software. Random effects model was used to calculate risk ratio (RR, 95% confidence interval [CI]) for dichotomous variables.

RESULTS

Thirty-one studies (13 prospective; 18 retrospective) with a total of 3,567 patients were included in the analysis. Follow-up time varied from 4 months to 10 years. Twelve studies involved only decompression; the rest were fusion. Overall RR of an unsatisfactory outcome was 2.12 [1.74, 2.58; p<.001] in patients with WC when compared with those without WC after surgery. The RR of an unsatisfactory outcome in patients with WC, compared with those without, was 2.09 [1.38, 3.17]; p<.01 among studies from Europe and Australia, and 2.14 [1.48, 2.60]; p<.01 among US studies. The RR of decompression-only procedures was 2.53 [1.85, 3.47]; p<.01,and 1.79 [1.45, 2.21]; p<.01 for fusion. Forty-three percent (209 of 491) of patients with WC did not return to work versus 17% (214 of 1250) of those without WC (RR 2.07 [1.43, 2.98]; p<.001). Twenty-five percent (74 of 292) and 13.5% (39 of 287) of patients had non-union in the compensated and non-compensated groups, respectively. This was not statistically significant (RR 1.33 [0.92, 1.91]; p=.07).

CONCLUSIONS

Workers' compensation patients have a two-fold increased risk of an unsatisfactory outcome compared with non-compensated patients after surgery. This association was consistent when studies were grouped by country or procedure. Compensation status must be considered in all surgical intervention studies.

Universal No-fault Compensation is Associated With Improved Return to Work Rates in Spine Fusion

STUDY DESIGN

Retrospective cohort study and systematic literature review.

OBJECTIVE

To examine the influence of "universal no-fault compensation" upon return-to-work rates in patients undergoing lumbar spinal fusion, and then to make comparison with workers' compensation (WC) and non-workers' compensation (non-WC) claimants.

SUMMARY OF BACKGROUND DATA

Compensation has an adverse influence upon outcomes and return to work in lumbar spinal fusion. It is unclear whether this is due to the compensation per se, or due to the features of WC including its adversarial environment, delayed resolution of claims, and need for disability enhancement to promote compensation. The New Zealand Accident Compensation Corporation (ACC) is a universal no-fault system offering early treatment and salary reimbursement. Given the differing features of these compensation systems, comparison of return-to-work rates may give insight into the differing outcomes for the two compensation systems.

METHODS

From a cohort of 428 patients undergoing lumbar spinal fusion, 178 patients covered by ACC system underwent a structured interview to determine pre-injury, pre-surgical, and post-surgical work status. A systematic literature review was performed relating to lumbar spine fusion, return to work, and WC.

RESULTS

The return-to-work rate for the ACC patients in work at the time of their injury was 81%. The systematic review of 21 studies including 2519 subjects revealed a return-to-work rate of 40% for WC patients, and 74% for non-WC patients (P < 0.001). There was a significantly greater return-to-work rate for ACC patients than WC patients (P < 0.001), but no difference between ACC and non-WC patients.

CONCLUSION

The return-to-work rates for a universal no-fault compensation system are higher than those under WC cover, and are compatible with non-WC cases. This suggests that the features of WC may contribute to the inferior return-to-work rates.

The Influence of No Fault Compensation on Functional Outcomes After Lumbar Spine Fusion

STUDY DESIGN

Prospective cohort study and systematic literature review.

OBJECTIVE

To compare the functional outcomes for lumbar spinal fusion in both compensation and noncompensation patients in an environment of universal no fault compensation and then to compare these outcomes with those in worker's compensation and nonworkers compensation cohorts from other countries.

SUMMARY OF BACKGROUND DATA

Compensation has an adverse effect on outcomes in spine fusion possibly based on adversarial environment, delayed resolution of claims and care, and increased compensation associated with prolonged disability. It is unclear whether a universal no fault compensation system would provide different outcomes for these patients. New Zealand's Accident Compensation Corporation (ACC) provides universal no fault compensation for personal injury secondary to accident and offers an opportunity to compare results with differing provision of compensation.

METHODS

A total of 169 patients undergoing lumbar spinal fusion were assessed preoperatively, at 1 year, and at long-term follow-up out to 14 years, using functional outcome measures and health-related quality-of-life measures. Comparison was made between those covered and not covered by ACC for 3 distinct diagnostic categories. A systematic literature review comparing outcomes in Worker's Compensation and non-Compensation cohorts was also performed.

RESULTS

The functional outcomes for both ACC and non-ACC cohorts were similar, with significant and comparable improvements over the first year that were then sustained out to long-term follow-up for both cohorts. At long-term follow-up, the health-related quality-of-life measures were the same between the 2 cohorts.The literature review revealed a marked difference in outcomes between worker's compensation and non-worker's compensation cohorts with a near universal inferior outcome for the compensation group.

CONCLUSION

The similarities in outcomes of patients undergoing lumbar spine fusion under New Zealand's universal no fault compensation system, when compared with the dramatically inferior outcomes for these patients under other worker's compensation systems, suggest that the system of compensation has a major influence on patient outcomes, and that change of compensation to a universal no fault system is beneficial for patients undergoing lumbar fusion surgery.

LEVEL OF EVIDENCE

2.

Substantial clinical benefit of minimally invasive lateral interbody fusion for degenerative spondylolisthesis

PURPOSE

Conventional lumbar arthrodesis for the treatment of degenerative spondylolisthesis (DS) is associated with high complication rates and variable clinical efficacy. Modern minimally invasive (MIS) approaches may reduce the morbidity and produce greater clinical improvement compared to traditional surgical techniques. The objective of this study is to report radiographic outcomes and evaluate clinical improvements in the context of substantial clinical benefit for DS patients treated with a MIS 90° lateral, transpsoas approach for lumbar interbody fusion.

METHODS

From 2005 to 2011, 60 consecutive patients were treated with MIS lateral interbody fusion for Grade I or II DS at a single institution. Mean patient age was 68 years, 75 % were female, and 30 % had undergone previous lumbar surgery. A total of 71 levels were treated, supplemental posterior fixation was used in 57 (95 %) cases, and 26 (43 %) patients underwent additional direct posterior decompression.

RESULTS

Average follow-up was 20.3 months. Average ORT, EBL, and LOS were 206 min, 83 cc, and 1.29 days, respectively. Complications occurred in 3 (5 %) patients. Transient approach-related thigh/groin pain was observed in 5 (8 %) cases. There were no cases of pseudoarthrosis. At 1 year, LBP improved 71 %, LP improved 68 %, ODI decreased 52 %, and SF-36 PCS and MCS improved 43 and 21 %, respectively. Substantial clinical benefit was met by 94.7 % of patients on NRS LBP, by 84.6 % on NRS LP, by 83.7 % on ODI, and by 66.7 % on SF-36 PCS. Disc height increased 71 % and segmental lordosis increased 27.8 % at treated levels. Foraminal height, width, and volume increased 19.7, 18.0, and 39.6 %, respectively. Slip improved 60.7 % with interbody fusion only and further improved to 69.2 % after the placement of supplemental instrumentation.

CONCLUSIONS

MIS lateral interbody fusion in the treatment of DS resulted in significant improvements in clinical and radiographic outcomes, with a low complication rate and a high proportion of patients achieving substantial clinical benefit.

Prospective randomized controlled trial of The Stabilis Stand Alone Cage (SAC) versus Bagby and Kuslich (BAK) implants for anterior lumbar interbody fusion

Background

Degenerative disc disease is common and debilitating for many patients. If conservative extensive care fails, anterior lumbar interbody fusion has proven to be an alternative form of surgical management. The Stabilis Stand Alone Cage(SAC) was introduced as a method to obtain stability and fusion. The purpose of this study was to determine whether the Stabilis Stand Alone Cage (SAC) is comparable in safety and efficacy to the Bagby and Kuslich (BAK) device.

Methods

As part of a prospective, randomized, controlled FDA trial, 73 patients underwent anterior interbody fusion using either the SAC(56%) or the BAK device (44%).

Results

Background characteristics were similar between the two groups. There was no significant difference between the SAC and BAK groups in mean operative time or mean blood loss during surgery. Adverse event rates did not differ between the groups. Assessment of plain radiographs could not confirm solid fusion in 63% of control and 71% of study patients. Functional scores from Owestry and SF-36 improved in both groups by the two-year follow-up. There were no significant differences between the SAC and BAK patients with respect to outcome.

Conclusions

Both the Stabilis Stand Alone Cage and the BAK Cage provided satisfactory improvement in function and pain relief, despite less than expected radiographic fusion rates. The apparent incongruency between fusion rates and functional outcomes suggests that either radiographs underestimate the true incidence of fusion, or that patients are obtaining good pain relief and improved function despite a lower rate of fusion than previously reported. This was a Level III study.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 5: correlation between radiographic outcome and function

In an effort to diminish pain or progressive instability, due to either the pathological process or as a result of surgical decompression, one of the primary goals of a fusion procedure is to achieve a solid arthrodesis. Assuming that pain and disability result from lost mechanical integrity of the spine, the objective of a fusion across an unstable segment is to eliminate pathological motion and improve clinical outcome. However, conclusive evidence of this correlation, between successful fusion and clinical outcome, remains elusive, and thus the necessity of documenting successful arthrodesis through radiographic analysis remains debatable. Although a definitive cause and effect relationship has not been demonstrated, there is moderate evidence that demonstrates a positive association between radiographic presence of fusion and improved clinical outcome. Due to this growing body of literature, it is recommended that strategies intended to enhance the potential for radiographic fusion are considered when performing a lumbar arthrodesis for degenerative spine disease.

Primary stiffness of a modified transforaminal lumbar interbody fusion cage with integrated screw fixation: cadaveric biomechanical study

STUDY DESIGN

In vitro biomechanical study using human fresh-frozen vertebrae.

OBJECTIVE

To investigate the influence of the additional screw fixation on the stability of a noncommercially available prototype transforaminal lumbar interbody fusion (TLIF) cage, when used as a stand-alone fusion device and in combination with pedicle screws (PSs).

SUMMARY OF BACKGROUND DATA

Generally interbody fusion cages are supplemented by additional fixation devices such as PS. However, such posterior instrumented techniques are associated with additional soft-tissue trauma and potentially increased complication rate. To limit such drawbacks, a conventional posterior TLIF cage was modified to allow supplemental screw fixation to the adjacent vertebral bodies, to increase initial stiffness and possibly allow as a stand-alone posterior interbody cage.

METHODS

Six monosegmental lumbar spine segments were loaded in a spine simulator with pure bending moments of 7.5 Nm in lateral bending, flexion/extension, and axial rotation. The following paradigms were tested: intact spines; a destabilized spine (i.e., after discectomy and unilateral facetectomy); and the modified TLIF cage with (i.e., fixed TLIF cage) and without (i.e., TLIF cage) integrated screw fixation as a stand-alone model and with and without additional posterior fixation with bilateral PS. The range of motion (RoM) was recorded by a 3-dimensional motion analysis system.

RESULTS

The TLIF cage with integrated screw fixation had minimal additional stabilizing effect in all motion planes with or without supplemental PS fixation. Moreover, compared with the intact spines, the stand-alone TLIF cage with and without integrated screw fixation did not reduce the RoM in any of the 3 motion planes. Comparison of the TLIF cage with integrated screw fixation to the TLIF cage supplemented with PS showed a significantly greater RoM in all testing conditions (P < 0.05).

CONCLUSION

In several testing paradigms, the prototype TLIF cage with the integrated screw fixation had limited effect in reducing RoM and providing stability. The PS was the main contributor in reducing RoM in the destabilized spine and remains the current "gold standard" in posterolateral spinal fixation.

LEVEL OF EVIDENCE

N/A.

Somatic perception, cultural differences and immigration: results from administration of the Modified Somatic Perception Questionnaire (MSPQ) to a sample of immigrants

The number of immigrants in Italy has doubled every 10 years from 1972 and Genoa hosts two large communities of immigrants from South America and Africa. We investigated differences in the somatic perception between immigrants and Italians and between South Americans and Africans living in the city of Genoa. During a 7 month period, an anonymous questionnaire asking for sociodemographic information and the Modified Somatic Perception Questionnaire (MSPQ) were administered to all immigrants accessing an outpatient clinic or the general practitioners offices. MSPQ mean scores were significantly higher in immigrant patients than in Italian patients, after adjusting for sex and age differences. We found no differences between South Americans and Africans in MSPQ score. The tendency to express discomfort through physical symptoms appears to be related to being a foreigner who arrived in Italy through a migratory trip and also to being a person who comes from a cultural context that is very different from the one of developed countries.

The da Vinci robotic surgical assisted anterior lumbar interbody fusion: technical development and case report

STUDY DESIGN

Technique development to use the da Vince Robotic Surgical System for anterior lumbar interbody fusion at L5-S1 is detailed. A case report is also presented.

OBJECTIVE

To evaluate and develop the da Vinci robotic assisted laparoscopic anterior lumbar stand-alone interbody fusion procedure.

SUMMARY OF BACKGROUND DATA

Anterior lumbar interbody fusion is a common procedure associated with potential morbidity related to the surgical approach. The da Vinci robot provides intra-abdominal dissection and visualization advantages compared with the traditional open and laparoscopic approach.

METHODS

The surgical techniques for approach to the anterior lumbar spine using the da Vinci robot were developed and modified progressively beginning with operative models followed by placement of an interbody fusion cage in the living porcine model. Development continued to progress with placement of fusion cage in a human cadaver, completed first in the laboratory setting and then in the operating room. Finally, the first patient with fusion completed using the da Vinci robot-assisted approach is presented.

RESULTS

The anterior transperitoneal approach to the lumbar spine is accomplished with enhanced visualization and dissection capability, with maintenance of pneumoperitoneum using the da Vinci robot. Blood loss is minimal. The visualization inside the disc space and surrounding structures was considered better than current open and laparoscopic techniques.

CONCLUSION

The da Vinci robot Surgical System technique continues to develop and is now described for the transperitoneal approach to the anterior lumbar spine.

LEVEL OF EVIDENCE

4.

Allograft cellular bone matrix in extreme lateral interbody fusion: preliminary radiographic and clinical outcomes

Introduction. Extreme lateral interbody fusion (XLIF) is a minimally disruptive alternative for anterior lumbar interbody fusion. Recently, synthetic and allograft materials have been increasingly used to eliminate donor-site pain and complications secondary to autogenous bone graft harvesting. The clinical use of allograft cellular bone graft has potential advantages over autograft by eliminating the need to harvest autograft while mimicking autograft's biologic function. The objective of this study was to examine 12-month radiographic and clinical outcomes in patients who underwent XLIF with Osteocel Plus, one such allograft cellular bone matrix. Methods. Forty (40) patients were treated at 61 levels with XLIF and Osteocel Plus and included in the analysis. Results. No complications were observed. From preoperative to 12-month postoperative followup, ODI improved 41%, LBP improved 55%, leg pain improved 43.3%, and QOL (SF-36) improved 56%. At 12 months, 92% reported being “very” or “somewhat” satisfied with their outcome and 86% being either “very” or “somewhat likely” to choose to undergo the procedure again. Complete fusion was observed in 90.2% (55/61) of XLIF levels. Conclusions. Complete interbody fusion with Osteocel Plus was shown in 90.2% of XLIF levels, with the remaining 9.8% being partially consolidated and progressing towards fusion at 12 months.

A radiological comparison of anterior fusion rates in anterior lumbar interbody fusion

Aim To compare anterior fusion in standalone anterior lumbar interbody fusion (ALIF) using cage and screw constructs and anterior cage-alone constructs with posterior pedicle screw supplementation but without posterior fusion. Methods Eighty-five patients underwent single- or two-level ALIF procedure for degenerative disk disease or lytic spondylolisthesis (SPL). Posterior instrumentation was performed without posterior fusion in all cases of lytic SPL and when the anterior cage used did not have anterior screw through cage fixation. Results Seventy (82%) patients had adequate radiological follow-up at a mean of 19 months. Forty patients had anterior surgery alone (24 single level and 16 two levels) and 30 had front-back surgery (15 single level and 15 two levels). Anterior locked pseudarthrosis was only seen in the anterior surgery-alone group when using the STALIF cage (Surgicraft, Worcestershire, UK) (37 patients). This occurred in five of the single-level surgeries (5/22) and nine of the two-level surgeries (9/15). Fusion was achieved in 100% of the front-back group and only 65% (26/40) of the anterior surgery-alone group. Conclusion Posterior pedicle screw supplementation without posterolateral fusion improves the fusion rate of ALIF when using anterior cage and screw constructs. We would recommend supplementary posterior fixation especially in cases where more than one level is being operated.

Complications during anterior surgery of the lumbar spine: an anatomically based study and review

Procedures involving anterior surgical decompression and fusion are being performed with increasing frequency for the treatment of a variety of pathological processes of the spine including trauma, deformity, infection, degenerative disease, failed-back syndrome, discogenic pain, metastases, and primary spinal neoplasms. Because these operations involve anatomy that is often unfamiliar to many neurological and orthopedic surgeons, a significant proportion of the associated complications are not related to the actual decompressive or fusion procedure but instead to the actual exposure itself. To understand the nature of these injuries, a detailed anatomical study and dissection was undertaken in six cadaveric specimens. Critical structures at risk in the abdomen and retroperitoneum were identified, and their anatomical relationships were categorized and photographed. These structures included the psoas muscle, kidneys, ureters, diaphragm and crura, esophageal hiatus, thoracic duct, greater splanchnic nerves, phrenic nerves, sympathetic chains, medial arcuate ligament, superior and inferior hypogastric plexus, segmental and radicular vertebral vessels, aorta, vena cava, median sacral artery, common iliac vessels, iliolumbar veins, lumbosacral plexus, and presacral hypogastric plexus. Based on these dissections and an extensive review of the literature, the authors provide a detailed anatomically based discussion of the complications associated with anterior lumbar surgery.

Economics of less invasive spinal surgery: an analysis of hospital cost differences between open and minimally invasive instrumented spinal fusion procedures during the perioperative period

BACKGROUND

There is great debate about the costs and benefits of technology-driven medical interventions such as instrumented lumbar fusion. With most analyses using charge data, the actual costs incurred by medical institutions performing these procedures are not well understood. The object of the current study was to examine the differences in hospital operating costs between open and minimally invasive spine surgery (MIS) during the perioperative period.

METHODS

Data were collected in the form of a prospective registry from a community hospital after specific Institutional Review Board approval was obtained. The analysis included consecutive adult patients being surgically treated for degenerative conditions of the lumbar spine, with either an MIS or open approach for two-level instrumented lumbar fusion. Patient outcomes and costs were collected for the perioperative period. Hospital operating costs were grouped by hospitalization/operative procedure, transfusions, reoperations, and residual events (health care interactions).

RESULTS

One hundred and one open posterior lumbar interbody fusion (Open group) and 109 MIS patients were treated primarily for stenosis coupled with instability (39.6% and 59.6%, respectively). Mean total hospital costs were $27,055.53 for the Open group and $24,320.16 for the MIS group. This represents a statistically significant cost savings of $2,825.37 (10.4% [95% confidence interval: $522.51-$5,128.23]) when utilizing MIS over traditional Open techniques. Additionally, residual events, complications, and blood transfusions were significantly more frequent in the Open group, compared to the MIS group.

CONCLUSIONS/LEVEL OF EVIDENCE

Utilizing minimally invasive techniques for instrumented spinal fusion results in decreased hospital operating costs compared to similar open procedures in the early perioperative period. Additionally, patient benefits of minimally invasive techniques include significantly less blood loss, shorter hospital stays, lower complication rate, and a lower number of residual events. Long-term outcome comparisons are needed to evaluate the efficacy of the two treatments.

LEVEL OF EVIDENCE

III CLINICAL RELEVANCE: This work represents a true cost-of-operating comparison between open and MIS approaches for lumbar spine fusion, which has relevance to surgeons, hospitals and payers in medical decision-making.

Direct lateral access lumbar and thoracolumbar fusion: preliminary results

PURPOSE

To describe the clinical outcomes and complications in a consecutive series of extreme lateral interbody fusion cases.

METHODS

Retrospective cohort review of 97 consecutive patients from three centers with minimum 6-month follow-up (mean 12 months). Functional status was evaluated by preoperative and last follow-up Oswestry Disability Index score. Leg and back pain were evaluated by visual analog scales. Complications were recorded and permanent complications and neurological impairment was actively investigated at last follow-up.

RESULTS

No permanent neurological impairment, vascular or visceral injuries were observed. Transient neurological symptoms presented in 7% of cases, all resolved within 1 month from surgery. Transient thigh discomfort was observed in 9%. Clinical success was recorded in 92% of cases.

CONCLUSIONS

Extreme lateral interbody fusion is a safe and effective technique for anterior interbody fusion.

The course of depression and anxiety in patients undergoing disc surgery: a longitudinal observational study

OBJECTIVE

This study examines longitudinal depression and anxiety rates in disc surgery patients in comparison to the general population, the change and associated determinants of depression and anxiety over time.

METHODS

The longitudinal observational study refers to 305 consecutive disc surgery patients (age range: 18-55 years). Depression and anxiety was assessed with the Hospital Anxiety and Depression Scale. Random effects regression models for unbalanced panel data were used.

RESULTS

Depression and anxiety decreases significantly during nine months after surgery. Depression rates vary between 23.6% (T0), 9.6% (T1) and 13.1% (T2). Only at T0 the depression rate differs significantly from the general population. Anxiety rates range between 23.7% (T0), 10.9% (T1) and 11.1% (T2). Compared to the general population anxiety rates are significantly higher at all three assessment points. Risk factors for anxiety or depression at the time of the surgery are psychiatric comorbidity before surgery, higher age, female gender, lower educational level, lower physical health status and higher pain intensity. Regarding depression and anxiety in the course of time significant time interactions were found for the existence of other chronic diseases, higher pain intensity and vocational dissatisfaction.

CONCLUSIONS

Compared to the general population patients undergoing herniated disc surgery are often affected by depression and anxiety during hospital treatment and also in the course of time. Multimodal diagnostics regarding psychological well-being, pain and physical health status may help to identify this risk group. The assistance by mental health professionals during hospital and rehabilitation treatment may reduce poor postoperative outcome.

Good functional outcome and adjacent segment disc quality 10 years after single-level anterior lumbar interbody fusion with posterior fixation

We reviewed the records of a prospective consecutive cohort to evaluate the clinical performance of anterior lumbar interbody fusion with a titanium box cage and posterior fixation, with emphasis on long-term functional outcome. Thirty-two patients with chronic low back pain underwent anterior lumbar interbody fusion and posterior fixation. Radiological and functional results (visual analogue scale [VAS] and Oswestry score) were evaluated. Adjacent segment degeneration (ASD) was evaluated radiologically and by magnetic resonance imaging (MRI). Twenty-five patients (78%) were available for follow-up. Functional scores showed significant improvement in pain and function up to the 2-year follow-up observation. At 4 years, there was some deterioration of the clinical results. At 10-year follow-up, results remained stable compared with 4-year results. MRI showed ASD in 3/25 (12%) above and 2/10 (20%) below index level (compared with absent preoperatively). ASD could not be related to clinical outcome in this study. Anterior lumbar interbody fusion and posterior fixation is safe and effective. Initial improvement in VAS and Oswestry scores is partly lost at the 4-year follow-up. Good clinical results are maintained at 10-year follow-up and are not related to adjacent segment degeneration.

Affective, anxiety, and substance-related disorders in patients undergoing herniated disc surgery

PURPOSE

At present only a small number of studies have investigated psychiatric comorbidity in disc surgery patients. Objectives of this study are (1) to examine the prevalence rate of comorbid affective, anxiety, and substance-related disorders in nucleotomy patients in comparison to the German general population and (2) to investigate associations between psychiatric comorbidity and socio-demographic and illness-related characteristics.

METHODS

The study refers to 349 consecutive disc surgery patients (response rate 87%) between the age of 18 and 55 years. The final study sample consists of 239 lumbar and 66 cervical nucleotomy patients. Face-to-face interviews were conducted approximately 3.45 days (SD 3.170) after disc surgery, during hospital stay. Psychiatric comorbidity was assessed by means of the Composite International Diagnostic Interview (CIDI-DIA-X). The corresponding data of the German general population were derived from the German National Health Interview and Examination Survey (GHS).

RESULTS

12-Month prevalence rates of any affective, anxiety or substance-related disorders range between 33.7% in cervical and 23.5% in lumbar disc surgery patients. Four-week prevalence rates of any affective, anxiety or substance disorder vary between 13.2% in cervical and 14.0% in lumbar nucleotomy patients. Disc surgery patients suffer more often from affective disorders and illicit substance abuse than the general population. Significant associations were found between psychiatric comorbidity and gender, as well as pain intensity.

CONCLUSIONS

Disc surgery patients show a higher risk to suffer from mental disorders than the general population. The assessment of psychiatric distress and the assistance by mental health professionals should be considered during hospital and rehabilitation treatment.

[Monosegmental anterior lumbar interbody fusion with the SynFix-LR™ device. A prospective 2-year follow-up study]

BACKGROUND

With anterior lumbar interbody fusion (ALIF) alone, the morbidity associated with a posterior approach can be avoided. In this study we evaluated the use of a PEEK cage with an integrated angle-stable locking plate (SynFix-LR™).

MATERIAL AND METHODS

Thirty-two patients with osteochondrosis at L4/5 or L5/S1 were treated with the SynFix-LR™. Follow-up at 0, 3, 6, 9, 12, and 24 months included the Oswestry Disability Index (ODI), visual analog scale (VAS), and questions regarding satisfaction and use of pain medication. The fusion rate was assessed by X-ray and computed tomography (CT) examination.

RESULTS

A significant reduction of the ODI and VAS was achieved (p<0.05) with a high rate of patient satisfaction. After 2 years, 79% of the patients were able to dispense with long-term use of analgesics. We observed a fusion rate of 93% (X-ray) and 70% (CT) at final follow-up.

CONCLUSION

The SynFix-LR™ device is a suitable option for the treatment of monosegmental osteochondrosis at L4/5 and L5/S1 with comparable or superior results in comparison to posterior or combined fusion techniques.

The impact of psychiatric comorbidity on the return to work in patients undergoing herniated disc surgery

INTRODUCTION

This study examines (1) return to work (RTW) and ability to work (ATW) rates, and the association with (2) psychiatric comorbidity and (3) socio-demographic, illness-related, vocational and rehabilitation-related characteristics in herniated disc surgery patients.

METHODS

In this longitudinal observational study 305 consecutive patients took part in face-to-face interviews during hospital stay. 277 patients also participated in a 3-month follow-up survey via telephone (drop-out rate 9%). Psychiatric comorbidity was assessed with the Composite International Diagnostic Interview (CIDI-DIA-X). Calculations were conducted via Chi-Square tests, independent T-tests and binary logistic regression analyses.

RESULTS

40.1% of the herniated disc patients in this study were able to RTW, 44.4% had regained their ATW 3 months after surgery. Psychiatric comorbidity appeared to be an important risk factor for RTW and ATW. Other risk factors were lower educational qualification, unemployment status, a lower subjective prognosis of gainful employment, a higher number of herniated discs in medical history, cervical disc surgery, and the existence of other chronic diseases, a longer hospital stay and higher pain intensity. Patients who did not RTW, or did not regain their ATW participated more often in inpatient rehabilitation.

CONCLUSIONS

Identifying a high risk group for RTW and ATW at an early age is of utmost importance for the purpose of improving rehabilitation effects and to make a return to the work place easier. Specific interventions, such as social-medical counselling, pain therapy and management, as well as the assistance of mental health professionals during hospital and rehabilitation treatment are recommended for this risk group.

Fusion rates of instrumented lumbar spinal arthrodesis according to surgical approach: a systematic review of randomized trials

BACKGROUND

Lumbar spine fusion rates can vary according to the surgical technique. Although many studies on spinal fusion have been conducted and reported, the heterogeneity of the study designs and data handling make it difficult to identify which approach yields the highest fusion rate. This paper reviews studies that compared the lumbosacral fusion rates achieved with different surgical techniques.

METHODS

Relevant randomized trials comparing the fusion rates of different surgical approaches for instrumented lumbosacral spinal fusion surgery were identified through highly sensitive and targeted keyword search strategies. A methodological quality assessment was performed according to the checklist suggested by the Cochrane Collaboration Back Review Group. Qualitative analysis was performed.

RESULTS

A literature search identified six randomized controlled trials (RCTs) comparing the fusion rates of different surgical approaches. One trial compared anterior lumbar interbody fusion (ALIF) plus adjunctive posterior transpedicular instrumentation with circumferential fusion and posterolateral fusion (PLF) with posterior lumbar interbody fusion (PLIF). Three studies compared PLF with circumferential fusion. One study compared three fusion approaches: PLF, PLIF and circumferential fusion.

CONCLUSIONS

One low quality RCT reported no difference in fusion rate between ALIF with posterior transpedicular instrumentation and circumferential fusion, and PLIF and circumferential fusion. There is moderate evidence suggesting no difference in fusion rate between PLF and PLIF. The evidence on the fusion rate of circumferential fusion compared to PLF from qualitative analysis was conflicting. However, no general conclusion could be made due to the scarcity of data, heterogeneity of the trials included, and some methodological defects of the six studies reviewed.

Minimally invasive surgery: lateral approach interbody fusion: results and review

STUDY DESIGN

A retrospective review of patients treated at 2 institutions with anterior lumbar interbody fusion using a minimally invasive lateral retroperitoneal approach, and review of literature.

OBJECTIVE

To analyze the outcomes from historical literature and from a retrospectively compiled database of patients having undergone anterior interbody fusions performed through a lateral approach.

SUMMARY OF BACKGROUND DATA

A paucity of published literature exists describing outcomes following lateral approach fusion surgery.

METHODS

Patients treated with extreme lateral interbody fusion (XLIF) were identified through retrospective chart review. Treatment variables included operating room (OR) time, estimated blood loss (EBL), length of hospital stay (LOS), complications, and fusion rate. A literature review, using the National Center for Biotechnology Information databases PubMed/MEDLINE and Google Scholar, yielded 14 peer-reviewed articles reporting outcomes scoring, complications, fusion status, long-term follow-up, and radiographic assessments related to XLIF. Published XLIF results were summarized and evaluated with current study data.

RESULTS

A total of 84 XLIF patients were included in the current cohort analysis. OR time, EBL, and length of hospital stay averaged 199 minutes, 155 mL, and 2.6 days, respectively, and perioperative and postoperative complication rates were 2.4% and 6.1%. Mean follow-up was 15.7 months. Sixty-eight patients showed evidence of solid arthrodesis and no subsidence on computed tomography and flexion/extension radiographs. Results were within the ranges of those in the literature. Literature review identified reports of significant improvements in clinical outcomes scores, radiographic measures, and cost effectiveness.

CONCLUSION

Current data corroborates and contributes to the existing body of literature describing XLIF outcomes. Procedures are generally performed with short OR times, minimal EBL, and few complications. Patients recover quickly, requiring minimal hospital stay, although transient hip/thigh pain and/or weakness is common. Long-term outcomes are generally favorable, with maintained improvements in patient-reported pain and function scores as well as radiographic parameters, including high rates of fusion.

Provocation lumbar diskography at previously fused levels

Recurrent or persistent low back pain (LBP) after lumbar fusion can be related to many factors. We reviewed the provocation lumbar diskogram (PLD) features and redo-fusion outcome in our patients evaluated for recurrent/persistent LBP after technically successful fusion. LD was performed in 27 patients with recurrent/persistent LBP after prior successful lumbar surgical fusion (31 fused levels: single-level fusion-23; two-level fusion-4). PLD response and imaging characteristics at fused and non-fused levels were assessed including: intra-diskal lidocaine response, diskogram-image/post-diskogram CT appearance, presence/absence of diskographic contrast leakage, and evidence of fusion integrity or hardware failure. Outcomes in patients having redo-fusion were assessed. Concordant pain was encountered at 15 out of 23 (65%) single-level fusions, non-concordant pain in one fusion with non-painful response in seven. Adjacent-level concordant pain was identified in seven out of 23 (30%) patients (three of 15 with painful fused levels; four of seven with non-painful fusions). In two-level fusions, concordant pain was encountered at one fused level in each patient. In painful fused levels, leaking and contained disks were encountered with partial or complete pain elimination after intra-diskal lidocaine injection. In anterior fusions, space or contrast surrounding the cage was noted at five of 11 levels. Pseudoarthrosis was noted only with trans-sacral screw fusions. Redo-fusion in 13 patients resulted in significant improvement in nine and moderate improvement in one. Patients with recurrent/persistent LBP after technically successful fusion may have a diskogenic pain source at the surgically fused or adjacent level confirmed by lidocaine-assisted PLD.

Clinical outcomes after posterolateral lumbar fusion in workers' compensation patients: a case-control study

STUDY DESIGN

Case-control propensity matched.

OBJECTIVE

To compare clinical outcomes after lumbar fusion in patients receiving workers' compensation with a case-matched control group who are not on workers' compensation.

SUMMARY OF BACKGROUND DATA

Previous studies have demonstrated poor outcomes in patients receiving workers' compensation after lumbar fusion. However, a case-control study where patients are matched for covariates known to affect outcomes after lumbar fusion, including baseline clinical outcome measures, has not been done.

METHODS

From 783 patients who underwent posterolateral fusion with complete preoperative and 2-year postoperative outcome measures, 60 patients who were receiving workers' compensation were identified. Outcome measures included the Oswestry Disability Index (ODI), Short Form-36 (SF-36), and back and leg pain numerical rating scales. Propensity scoring technique was used to match these patients with a control group not receiving workers' compensation using sex, age, smoking status, body mass index, diagnosis, number of levels fused, preoperative ODI, SF-36 Physical Component Summary (PCS), SF-36 Mental Component Summary, and back and leg pain scores, producing 58 matched pairs.

RESULTS

There were no significant differences between the demographics, job classification, and preoperative outcome scores in the two groups. At 2 years after operation, patients not receiving workers' compensation had a significantly greater improvement in ODI (P=0.009) and SF-36 PCS (P=0.007) compared with those receiving workers' compensation. Although patients not receiving workers' compensation had greater improvements in back and leg pain compared with those receiving workers' compensation, this did not reach statistical significance (P=0.079). The mean 2-year ODI, SF-36 PCS, and back pain raw scores of patients receiving workers' compensation were significantly lower than those not receiving workers' compensation. Only 19% of workers' compensation patients achieved minimum clinically important difference in terms of ODI compared with 36% of those not receiving workers' compensation (P=0.061). Only 16% of workers' compensation patients achieved SF-36 PCS minimum clinically important difference compared with 40% of those not receiving workers' compensation (P=0.006).

CONCLUSION

After controlling for covariates known to affect outcomes after lumbar fusion, patients on workers' compensation have significantly less improvement of clinical outcomes in both mean change in ODI and SF-36 PCS, as well as the number of patients achieving substantial clinical benefit. The improvement in back pain was similar between the two groups, but patients on workers' compensation remained more disabled after lumbar fusion. Differences in outcomes may be related to unidentified covariates associated with workers' compensation status.