Surgical Treatment Of Degenerative Spondylolisthesis Research Articles

Invasiveness of decompression surgery affects modeled lumbar spine kinetics in patients with degenerative spondylolisthesis.

Introduction: The surgical treatment of degenerative spondylolisthesis with accompanying spinal stenosis focuses mainly on decompression of the spinal canal with or without additional fusion by means of a dorsal spondylodesis. Currently, one main decision criterion for additional fusion is the presence of instability in flexion and extension X-rays. In cases of mild and stable spondylolisthesis, the optimal treatment remains a subject of ongoing debate. There exist different opinions on whether performing a fusion directly together with decompression has a potential benefit for patients or constitutes overtreatment. As X-ray images do not provide any information about internal biomechanical forces, computer simulation of individual patients might be a tool to gain a set of new decision criteria for those cases. Methods: To evaluate the biomechanical effects resulting from different decompression techniques, we developed a lumbar spine model using forward dynamic-based multibody simulation (FD_MBS). Preoperative CT data of 15 patients with degenerative spondylolisthesis at the level L4/L5 who underwent spinal decompression were identified retrospectively. Based on the segmented vertebrae, 15 individualized models were built. To establish a reference for comparison, we simulated a standardized flexion movement (intact) for each model. Subsequently, we performed virtual unilateral and bilateral interlaminar fenestration (uILF, bILF) and laminectomy (LAM) by removing the respective ligaments in each model. Afterward, the standardized flexion movement was simulated again for each case and decompression method, allowing us to compare the outcomes with the reference. This comprehensive approach enables us to assess the biomechanical implications of different surgical approaches and gain valuable insights into their effects on lumbar spine functionality. Results: Our findings reveal significant changes in the biomechanics of vertebrae and intervertebral discs (IVDs) as a result of different decompression techniques. As the invasiveness of decompression increases, the moment transmitted on the vertebrae significantly rises, following the sequence intact ➝ uILF ➝ bILF ➝ LAM. Conversely, we observed a reduction in anterior-posterior shear forces within the IVDs at the levels L3/L4 and L4/L5 following LAM. Conclusion: Our findings showed that it was feasible to forecast lumbar spine kinematics after three distinct decompression methods, which might be helpful in future clinical applications.

Comparison of surgical outcomes of degenerative spondylolisthesis with open or minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF)

Introduction. One of the most commonly used surgical treatment methods for degenerative lumbar spondylolisthesis (DLS) is transforaminal lumbar interbody fusion (TLIF). It can be performed either with an open classic posterior midline approach or the minimally invasive (MIS) method using Wiltse paraspinal intermuscular accesses. Aim. To prospectively compare clinical and radiological outcomes of DLS treatment with open (O) or (MIS) TLIF. Materials and methods. Forty six surgically treated patients who met the study criteria were divided into two groups according to the access method used: O group – 24 patients, MIS group – 22 patients. Clinical and radiological outcomes were evaluated before and after the surgery and after the follow-up period in both groups. The clinical peri and postoperative parameters and complications, back and leg pain with the VAS scale, and the outcomes in the ODI scale were evaluated. Radiological outcomes were measured with the standing X-ray images in the AP and lateral projections, as well as MRI/CT and functional X-rays. During statistical comparisons, both groups were adjusted in terms of pre-operative and postoperative data. Results. Preoperative demographic data in both groups did not differ significantly, except for the follow–up period, which was longer for the O group (mean 33.2 months), and 19.5 months for the MIS group. Both VAS and ODI clinical outcomes improved in both groups. Patients from the MIS group achieved significantly better clinical results immediately after the procedure and in the early outcomes. After the follow–up period, no significant differences were found. In the MIS group, only blood loss and the length of the postoperative stay were significantly lower than in the O group. The X-ray doses were significantly higher in the MIS group. Postoperative X-ray parameters improved in both groups with no significant differences, except for the slip correction, which was better in the O group. Conclusions. Both TLIF methods lead to significant clinical and radiological improvement in patients with DLS. In certain aspects, MIS has advantages over the “open” TLIF technique in the surgical treatment of degenerative spondylolisthesis.

Analysis of Patient-reported Outcomes Measures Used in Lumbar Fusion Surgery Research for Degenerative Spondylolisthesis.

Meta-analyses. This study aims to document the most common Patient-reported Outcome Measures (PROMs) used to assess lumbar fusion surgery outcomes and provide an estimate of the average improvement following surgical treatment. As health care institutions place more emphasis on quality of care, accurately quantifying patient perceptions has become a valued tool in measuring outcomes. To this end, greater importance has been placed on the use of PROMs. This is a systemic review and meta-analysis of randomly controlled trials published between 2014 and 2019 assessing surgical treatment of degenerative spondylolisthesis. A fixed effect size model was used to calculate mean difference and a 95% confidence interval (95% CI). Linear regression was used to calculate average expected improvement, adjusted for preoperative scores. A total of 4 articles (7 study groups) were found for a total of 444 patients. The 3 most common PROMs were Oswestry Disability Index (ODI) (n=7, 100%), Short-Form-12 or Short-Form-36 (SF-12/36) (n=4, 57.1%), and visual analog scale-back pain (n=3, 42.8%). Pooled average improvement was 24.12 (95% CI: 22.49-25.76) for ODI, 21.90 (95% CI: 19.71-24.08) for SF-12/36 mental component score, 22.74 (95% CI: 20.77-24.71) for SF-12/36 physical component score, and 30.87 (95% CI: 43.79-47.97) for visual analog scale-back pain. After adjusting for preoperative scores, patients with the mean preoperative ODI (40.47) would be expected to improve by 22.83 points postoperatively. This study provides a range of expected improvement for common PROMs used to evaluate degenerative spondylolisthesis with the goal of equipping clinicians with a benchmark value to use when counseling patients regarding surgery. In doing so, it hopes to provide a comparison point by which to judge individual patient improvement. Level II.

Variation in surgical treatment of degenerative spondylolisthesis in Canada: surgeon assessment of stability and impact on treatment.

Controversy exists regarding the optimal surgical treatment of degenerative lumbar spondylolisthesis (DS). Not all DS patients are the same, and the degree to which inherent stability may dictate treatment is unknown. The purpose of this study was to determine the variability in surgical approach relative to surgeon classified stability. The secondary objective was to compare patient-reported outcomes (PROs) across different surgical techniques and grades of stability. Patients prospectively enrolled from eleven tertiary care institutions and followed from 2015 to 2019. The surgical technique was at the surgeon's discretion. Surgeons were asked to grade the degree of instability based on the degenerative spondylolisthesis instability classification system (DSIC). DSIC categorizes three different types (I-stable, II-potentially unstable, and III-unstable). One-year changes in PROs were compared between each group. Multivariable regression was used to identify any characteristics that explained variability in treatment. There were 323 patients enrolled in this study. Surgeons' stability classification versus procedure [decompression alone (D)/decompression and posterolateral fusion (D-PL)/and decompression with posterior/transforaminal lumbar interbody fusion (D-PLIF/TLIF)] were as follows: type I (n = 91): D-41%/D-PL-13%/D-PLIF/TLIF-46%; type II (n = 175): D-23%/D-PL-17%/D-PLIF/TLIF-60%; and type III (n = 57):(D-0%/D-PL-14%/D-PLIF/TLIF-86%). Type I patients undergoing D-PL had some improvements in EQ-5D and NRS versus those undergoing D-PLIF/TLIF but otherwise there were no other significant differences between groups. Regression analysis demonstrated advanced age (OR = 1.06, CI 1.02-10.12) andtype I (OR = 2.61, CI 1.17-5.81) were associated with receiving decompression surgery alone. There exists considerable variation in surgical management of DS in Canada. Given similar PROs in two of the three groups, there is potential to tailor surgical intervention and improve resource utilization.

Impact of surgeon and hospital factors on surgical decision-making for grade 1 degenerative lumbar spondylolisthesis: a Quality Outcomes Database analysis.

Surgical treatment for degenerative spondylolisthesis has been proven to be clinically challenging and cost-effective. However, there is a range of thresholds that surgeons utilize for incorporating fusion in addition to decompressive laminectomy in these cases. This study investigates these surgeon- and site-specific factors by using the Quality Outcomes Database (QOD). The QOD was queried for all cases that had undergone surgery for grade 1 spondylolisthesis from database inception to February 2019. In addition to patient-specific covariates, surgeon-specific covariates included age, sex, race, years in practice (0-10, 11-20, 21-30, > 30 years), and fellowship training. Site-specific variables included hospital location (rural, suburban, urban), teaching versus nonteaching status, and hospital type (government, nonfederal; private, nonprofit; private, investor owned). Multivariable regression and predictor importance analyses were performed to identify predictors of the treatment performed (decompression alone vs decompression and fusion). The model was clustered by site to account for site-specific heterogeneity in treatment selection. A total of 12,322 cases were included with 1988 (16.1%) that had undergone decompression alone. On multivariable regression analysis clustered by site, adjusting for patient-level clinical covariates, no surgeon-specific factors were found to be significantly associated with the odds of selecting decompression alone as the surgery performed. However, sites located in suburban areas (OR 2.32, 95% CI 1.09-4.84, p = 0.03) were more likely to perform decompression alone (reference = urban). Sites located in rural areas had higher odds of performing decompression alone than hospitals located in urban areas, although the results were not statistically significant (OR 1.33, 95% CI 0.59-2.61, p = 0.49). Nonteaching status was independently associated with lower odds of performing decompression alone (OR 0.40, 95% CI 0.19-0.97, p = 0.04). Predictor importance analysis revealed that the most important determinants of treatment selection were dominant symptom (Wald χ2 = 34.7, accounting for 13.6% of total χ2) and concurrent diagnosis of disc herniation (Wald χ2 = 31.7, accounting for 12.4% of total χ2). Hospital teaching status was also found to be relatively important (Wald χ2 = 4.2, accounting for 1.6% of total χ2) but less important than other patient-level predictors. Nonteaching centers were more likely to perform decompressive laminectomy with supplemental fusion for spondylolisthesis. Suburban hospitals were more likely to perform decompression only. Surgeon characteristics were not found to influence treatment selection after adjustment for clinical covariates. Further large database registry experience from surgeons at high-volume academic centers at which surgically and medically complex patients are treated may provide additional insight into factors associated with treatment preference for degenerative spondylolisthesis.

Comparative Effectiveness of Microdecompression Alone vs Decompression Plus Instrumented Fusion in Lumbar Degenerative Spondylolisthesis

Conflicting evidence and large practice variation are present in the surgical treatment of degenerative spondylolisthesis. More than 90% of surgical procedures in the United States include instrumented fusion compared with 50% or less in other countries. To evaluate whether the effectiveness of microdecompression alone is noninferior to decompression with instrumented fusion in a real-world setting. This multicenter comparative effectiveness study with a noninferiority design assessed prospective data from the Norwegian Registry for Spine Surgery. From September 19, 2007, to December 21, 2015, 1376 patients at 35 Norwegian orthopedic and neurosurgical departments underwent surgery for lumbar spinal stenosis with degenerative spondylolisthesis without scoliosis. After excluding patients undergoing laminectomy alone, fusion without instrumentation, or surgery in more than 2 levels and those with a former operation at the index level, 794 patients were included in the analyses, regardless of missing or incomplete follow-up data, before propensity score matching. Data were analyzed from March 20 to October 30, 2018. Microdecompression alone or decompression with instrumented fusion. A reduction from baseline of 30% or greater in the Oswestry Disability Index at 12-month follow-up. After propensity score matching, 570 patients (413 female [72%]; mean [SD] age, 64.7 [9.5] years) were included for comparison, with 285 undergoing microdecompression (mean [SD] age, 64.6 [9.8] years; 205 female [72%]) and 285 undergoing decompression with instrumented fusion (mean [SD] age, 64.8 [9.2] years; 208 female [73%]). The proportion of each type of procedure varied between departments. However, changes in outcome scores varied within patients but not between departments. The proportion of patients with improvement in the Oswestry Disability Index of at least 30% was 150 of 219 (68%) in the microdecompression group and 155 of 215 (72%) in the instrumentation group. The 95% CI (-12% to 5%) for the difference of -4% was above the predefined margin of noninferiority (-15%). Microdecompression alone was associated with shorter operation time (mean [SD], 89 [44] vs 180 [65] minutes; P < .001) and shorter hospital stay (mean [SD], 2.5 [2.4] vs 6.4 [3.0] days; P < .001). Among patients with degenerative spondylolisthesis, the clinical effectiveness of microdecompression alone was noninferior to that of decompression with instrumented fusion. Microdecompression alone was also associated with shorter durations of surgery and hospital stay, supporting the suggestion that the less invasive procedure should be considered for most patients.

Canadian Spine SocietyPresentation CPSS1: Spinal insufficiency fracture in the geriatric pediatric spinePresentation CPSS2: The clinical significance of tether breakages in anterior vertebral body growth modulation: a 2-year postoperative analysisPresentation CPSS3: Anterior vertebral body growth modulation for idiopathic scoliosis: early, mid-term and late complicationsPresentation CPSS4: Ovine model of congenital chest wall and spine deformity with alterations of respiratory mechanics: follow-up from

Canadian Spine SocietyPresentation CPSS1: Spinal insufficiency fracture in the geriatric pediatric spinePresentation CPSS2: The clinical significance of tether breakages in anterior vertebral body growth modulation: a 2-year postoperative analysisPresentation CPSS3: Anterior vertebral body growth modulation for idiopathic scoliosis: early, mid-term and late complicationsPresentation CPSS4: Ovine model of congenital chest wall and spine deformity with alterations of respiratory mechanics: follow-up from

Development of a machine learning algorithm predicting discharge placement after surgery for spondylolisthesis.

We aimed to develop a machine learning algorithm that can accurately predict discharge placement in patients undergoing elective surgery for degenerative spondylolisthesis. The National Surgical Quality Improvement Program (NSQIP) database was used to select patients that underwent surgical treatment for degenerative spondylolisthesis between 2009 and 2016. Our primary outcome measure was non-home discharge which was defined as any discharge not to home for which we grouped together all non-home discharge destinations including rehabilitation facility, skilled nursing facility, and unskilled nursing facility. We used Akaike information criterion to select the most appropriate model based on the outcomes of the stepwise backward logistic regression. Four machine learning algorithms were developed to predict discharge placement and were assessed by discrimination, calibration, and overall performance. Nine thousand three hundred and thirty-eight patients were included. Median age was 63 (interquartile range [IQR] 54-71), and 63% (n = 5,887) were female. The non-home discharge rate was 18.6%. Our models included age, sex, diabetes, elective surgery, BMI, procedure, number of levels, ASA class, preoperative white blood cell count, and preoperative creatinine. The Bayes point machine was considered the best model based on discrimination (AUC = 0.753), calibration (slope = 1.111; intercept = - 0.002), and overall model performance (Brier score = 0.132). This study has shown that it is possible to create a predictive machine learning algorithm with both good accuracy and calibration to predict discharge placement. Using our methodology, this type of model can be developed for many other conditions and (elective) treatments. These slides can be retrieved under Electronic Supplementary Material.

Posterior Lumbar Interbody Fusion in Degenerative Spondylolisthesis

Background: degenerative spondylolisthesis is one of causes of low back pain in older patients and it’s referring to a forward slippage of a lumbar, with an intact neural arch. Uncommon before the age of 50 years, it is more common in women and particularly in blacks, with a male: female ratio of 1:6. Posterior lumbar interbody fusion surgery is one of an effective surgery in treatment of patients with degenerative spondylolisthesis and can make significant relief in low back pain and disability. It has amore advantages more than other type of back surgery through restoring of vertebral height and restricts motion of the vertebral segment. Objective: this study aimed to evaluate the surgical treatment of degenerative spondylolisthesis by Posterior Lumber Interbody Fusion. Patients and Methods: this was a prospective study carried out at Al-Azhar University Hospitals on 15 patients with degenerative spondylolithesis operated by posterior lumber interbody fusion and assessment pre-operative, one day, three months and six months post-operative by oswestry disability index .also according to visual analogue scale pre and post-operative then assessment of the fusion according to lenke classification. Results: the mean preoperative ODI was (70.2%±5.5) one day Postoperative ODI was (10.93%±4.76), after 3 months was (10.67±7.97) and 6 months the mean post-operative was (12.76±14.25). According to VAS for back pain pre-operative was (6.9± 0.9) preoperative and show marked improvement and the main postoperative value according to VAS is (1.53±1.126) for leg pain The mean value Pre-operative according to VAS was :(9.06±0.7) and the mean value Post operativeis (2.0±1.41) the mean outcome was 87.24 % ranged from 38% to 94% the main complication noted the adjacent segment degenerative disease and Dural tear. Conclusion: posterior lumber interbody fusion in degenerative spondylolisthesis is a very good option.

Patient Profiling Can Identify Spondylolisthesis Patients at Risk for Conversion from Nonoperative to Operative Treatment.

Background:Factors that are relevant to the decision regarding the use of surgical treatment for degenerative spondylolisthesis include disease-state severity and patient quality-of-life expectations. Some factors may not be easily appraised by the surgeon. In prospective trials involving patients undergoing nonoperative and operative treatment, there are instances of crossover in which patients from the nonoperative group undergo surgery. Identifying and understanding patient characteristics that may influence crossover from nonoperative to operative treatment will aid understanding of what motivates patients toward pursuing surgery.Methods:Patients with degenerative spondylolisthesis who were randomized to nonoperative care in a prospective, multicenter study were evaluated over 8 years of enrollment. Two cohorts were defined: (1) the surgery cohort (patients who underwent surgery at any point) and (2) the nonoperative cohort (patients who did not undergo surgery). A Cox proportional hazards model, modeling time to surgery, was used to explore demographic data, clinical diagnoses, and patient expectations and attitudes after adjusting for other variables. A subanalysis was performed on surgery within 6 months after enrollment and surgery >6 months after enrollment.Results:One hundred and forty-five patients who had been randomized to nonoperative treatment, 80 of whom crossed over to surgery, were included. In analyzing baseline differences between the 2 cohorts, patients who underwent surgery were younger; however, there were no significant difference between the cohorts in terms of race, sex, or comorbidities. Treatment preference, greater Oswestry Disability Index score, marital status, and no joint problems were predictors of crossover to surgery. Clinical factors, including stenosis, neurological deficits, and listhesis levels, did not show a significant relationship with crossover. At the time of long-term follow-up, the surgery cohort showed significantly greater long-term improvement in health-related quality of life (p < 0.001). The difference was maintained throughout follow-up.Conclusions:Neurological symptoms and diagnoses, including listhesis and stenosis severity, did not predict crossover from nonoperative care to surgery. Attitudes toward surgery, greater Oswestry Disability Index score, marital status, and no joint problems were independent predictors of crossover from nonoperative to operative care. Certain demographic characteristics were associated with higher rates of crossover, although they were connected to patient attitudes toward surgery.Level of Evidence:Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Treatment for Degenerative Lumbar Spondylolisthesis: Current Concepts and New Evidence.

Current guidelines for the optimal treatment degenerative spondylolisthesis are weak and based on limited high-quality evidence. There is some moderate evidence that decompression alone may be a feasible treatment with lower surgical morbidity and similar outcomes to fusion when performed in a select population with a low-grade slip. Similarly, addition of interbody fusion may be best suited to a subset of patients with high-grade degenerative spondylolisthesis, although this remains controversial. Minimally invasive techniques are increasingly being utilized for both decompression and fusion surgeries with more and more studies showing similar outcomes and lower postoperative morbidity for patients. This will likely be an area of continued intense research. Finally, the role of spondylolisthesis reduction will likely be determined as further investigation into optimal sagittal balance and spinopelvic parameters is conducted. Future identification of ideal thresholds for sagittal vertical axis and slip angle that will prevent progression and reoperation will play an important role in surgical treatment planning. Current evidence supports surgical treatment of degenerative spondylolisthesis. While posterolateral spinal fusion remains the treatment of choice, the use of interbodies and decompressions without fusion may be efficacious in certain populations. However, additional high-quality evidence is needed, especially in newer areas of practice such as minimally invasive techniques and sagittal balance correction.

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.

Radiographic Restoration of Sagittal Spinopelvic Alignment After Posterior Lumbar Interbody Fusion in Degenerative Spondylolisthesis

A retrospective study. This study was aimed to analyze the changes in spinopelvic parameters after surgical correction of degenerative spondylolisthesis and to determine which deformity is most responsible for changes in sagittal spinopelvic alignment. The basic deformities of degenerative spondylolisthesis are forward slippage of the vertebral body, segmental kyphotic angle, and loss of disk height. Correction of those deformities during surgery will subsequently affect the spinopelvic parameters. A few studies have reported the changes of sagittal spinopelvic alignment after surgical treatment of isthmic spondylolisthesis. However, there appears to be relatively little information regarding degenerative spondylolisthesis. Fifty-three patients with L4-L5 degenerative spondylolisthesis were included. All patients underwent posterior lumbar interbody fusion and posterior instrumentation. Back pain, as the clinical outcome, was evaluated by visual analogue scale (VAS). The preoperative and postoperative spinopelvic parameters, including sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), and L1 axis S1 distance were measured, and then the correlations between spinopelvic parameters and local deformity parameters such as slip degree, slip angle (SA), and height of the intervertebral disk were evaluated. After surgical correction of local deformity, all spinopelvic parameters changed subsequently: PT and L1 axis S1 distance had a decrease, SS and LL had an increase. VAS score decreased from 6.1±2.3 before surgery to 2.4±1.7 at the final follow-up assessment. Patients with VAS score changes ≥3 showed significantly higher SS and LL, and lower PT compared with those with VAS score changes <3. Among deformity parameters, restoration of the SA revealed significant correlation with improvement of LL (r=0.32, P=0.02), increase of SS (r=0.29, P=0.03), and decrease of PT (r=-0.29, P=0.03). Surgical correction of degenerative spondylolisthesis with posterior lumbar interbody fusion and posterior instrumentation resulted in relief of back pain, which may be associated with improvement of sagittal spinopelvic alignment. Surgeons should consider deformity parameters, especially the SA, in the surgical treatment of degenerative spondylolisthesis.

Indikationen zur Korrekturspondylodese bei degenerativer Spondylolisthesis

There is no general consensus about indications for surgical treatment of degenerative spondylolisthesis. This is--in part--due to a paucity of knowledge of its natural history and outcomes of conservative treatment, as well as a relatively small number of sufficiently powered outcome studies for surgical treatment. We aim to provide an overview of current surgical techniques and deduce indications based on two simple principles: presence of neurological deficits and instability. Today, decompression and instrumented fusion is the standard of care. However, the complete armamentarium of possible treatment options should be carefully considered, and the adequate procedures and instruments used should be chosen individually, when a decision to operate is made.

Two-Year Comparative Outcomes of MIS Lateral and MIS Transforaminal Interbody Fusion in the Treatment of Degenerative Spondylolisthesis: Part II: Radiographic Findings.

Prospective, multicenter, institutional review board approved study with randomized and observational study arms. The purpose of this study was to compare radiographic outcomes between minimally invasive transforaminal (MIS TLIF) or MIS lateral interbody fusion (XLIF) in the treatment of patients with low-grade degenerative spondylolisthesis with stenosis through 2-year postoperative. Few reports exist comparing different MIS approaches directly in the treatment of similar pathology, as most studies report differences between MIS and open procedures. A total of 55 patients undergoing surgical treatment for degenerative spondylolisthesis with spinal stenosis at one or two contiguous levels between L1 and L5 were enrolled. Twenty-nine patients were treated with XLIF and 26 patients were treated with MIS TLIF. Disc height was significantly improved from preoperative at all postoperative time points in both groups, though the XLIF group experienced less subsidence and resultant loss of disc height than the MIS TLIF group by 24-month postoperative (P = 0.002). Postoperative change in central canal area was statistically greater in the MIS TLIF compared with the XLIF group (43.1 mmvs. 4.1 mm, P = 0.028). At several postoperative time points, foraminal height and area on the ipsilateral side and foraminal height on the contralateral side to the approach were significantly increased postoperatively in the XLIF group, and the magnitude of ipsilateral height increase was greater than in the MIS TLIF cohort (P < 0.05).Using fusion criteria of <3° range of motion and <3 mm translation on plain radiographs, 100% of patients in both groups were solidly fused at 24-month postoperative. Using computed tomography fusion criteria of presence of intervertebral bridging bone, 100% (32/32) of XLIF levels and 96% (25/26) of MIS TLIF levels were solidly bridged (P = 0.448). Different mechanisms of stenosis correction (direct vs. indirect) between the MIS TLIF and XLIF groups studied resulted in several significantly different radiographic characteristics. Despite these differences, both groups of patients experienced significant and maintained clinical improvements with high fusion rates at 2-year follow-up, suggesting that the mechanism of correction may not be critical and both MIS procedures are reasonable treatment options for degenerative spondylolisthesis with stenosis. 2.

Two-year Comparative Outcomes of MIS Lateral and MIS Transforaminal Interbody Fusion in the Treatment of Degenerative Spondylolisthesis. Part I

A prospective, multicenter, institutional review board (IRB) approved study with randomized and observational study arms.The purpose of this study was to compare clinical outcomes between minimally invasive transforaminal (MIS TLIF) and MIS lateral interbody fusion (XLIF) in the treatment of patients with low-grade degenerative spondylolisthesis with stenosis through two years postoperative.Few reports exist comparing different MIS approaches directly in the treatment of similar pathology, as most studies report differences between MIS and open procedures.A total of 55 patients undergoing surgical treatment for degenerative spondylolisthesis with spinal stenosis at one or two contiguous levels between L1 and L5 were enrolled. Twenty-nine patients were treated with XLIF and 26 patients were treated with MIS TLIF.Operative time and length of stay were similar between the XLIF and MIS TLIF groups (171 vs 186 minutes; two days for each group). Blood loss was significantly lower in the XLIF group, with 79% of XLIF cases and 27% of MIS TLIF cases resulting in <100 mL of blood loss, P < 0.001. Hip flexion weakness was more common in the XLIF group (31%) than in the MIS TLIF group (0%). One patient in the XLIF group had a new distal motor weakness and three patients in the XLIF group and two patients in the MIS TLIF group had new sensory changes postoperatively, all of which resolved by 12 months postoperative. Back and leg pain for both XLIF and MIS TLIF groups improved significantly from baseline to 24 months postoperative, with 73% improvement in the XLIF and 64% in the MIS TLIF group. Worst leg pain showed similar improvements through two years postoperative, with a 79% decrease seen in the XLIF group and 74% in the MIS TLIF group. Disability (ODI) improved 53% in the XLIF group and 57% in the MIS TLIF group.Despite different mechanisms of action (indirect vs direct decompression), mid-term clinical outcomes between XLIF and MIS TLIF were similar. These two-year results suggest that both XLIF and MIS TLIF are reasonable MIS approaches for the treatment of lumbar degenerative pathology.2.

A novel minimally invasive technique for lumbar decompression, realignment, and navigated interbody fusion

We present a novel, minimally invasive, navigation-guided approach for surgical treatment of degenerative spondylolisthesis (DS) that is a hybrid of the two most common techniques, posterior interbody fusion (PLIF) and transforaminal interbody fusion (TLIF). DS is an acquired condition with intersegmental instability of one or more lumbar motion segments. Seven patients with single level lumbar DS underwent lumbar arthrodesis utilizing the hybrid technique (HLIF) in our center. Using a standard unilateral midline approach a decompression and partial facetectomy on one side was performed, allowing for implantation of a specially designed interbody cage. Pedicle screws were placed using neuronavigation in a vertical vector on the side of the partial facetectomy and dorsolaterally (percutaneous) on the contralateral side. Patient and operative data, numeric rating scale (NRS) pain scores, core outcome measures index (COMI) and Oswestry disability index (ODI) were recorded preoperatively as well as 6 weeks, 3months, 6months and 1year after surgery. All patients completed the 1year follow-up. There was significant postoperative improvement of NRS, COMI and ODI scores at all postoperative follow-up time points (p<0.05). The radiological assessments of realignment showed a reduction of listhesis from an average of 21.04% (standard deviation [SD] 5.1) preoperatively to 9.14% (SD 4.0) postoperatively (p<0.001). The average blood loss was 492ml. Post-procedure CT scans demonstrated correct implant placement in all but one patient who required a revision of a single pedicle screw. HLIF allows thorough decompression as well as realignment and interbody fusion for patients with DS and may help reduce tissue trauma in comparison to other minimally invasive lumbar fusion techniques.

Cost-effectiveness of surgical treatment for degenerative spondylolisthesis and spinal stenosis.

Systematic review. To identify cost-effective treatment strategies for lumbar spine degenerative diseases. There is a paucity of literature assisting physicians and society regarding the cost-efficiency of management of lumbar spine conditions. Limited articles on selective operative and nonoperative therapies have been published for a variety of lumbar conditions. A systematic search of PubMed, EMBASE, the Cochrane Collaboration data base, University of York, Centre for Reviews and Dissemination (National Health Services Economic Evaluation Database and health technology assessment), and the Tufts CEA Registry was conducted through December 16, 2013. Three specific questions were addressed for adult patients: (1) What is the evidence that surgery is cost-effective compared with nonsurgical management for lumbar degenerative spondylolisthesis or stenosis? (2) What is the evidence that fusion is cost-effective compared with no fusion for degenerative spondylolisthesis or stenosis? and (3) What is the evidence that instrumentation is cost-effective compared with none for degenerative spondylolisthesis? The Quality of Health Economic Studies instrument was used to provide an initial basis for critical appraisal of included economic studies. Articles were further refined with individual review based on inclusion/exclusion criteria. Initial search resulted in 122 potentially relevant citations, 115 of which were excluded at title and abstract levels and 3 at full-text reviews, leaving 5 for analysis. No non-English language text met inclusion/exclusion criteria. All studies illustrated a clinical benefit of surgical treatment as measured by quality-adjusted life year (0.11-8.05). Surgical treatments had a greater financial cost than nonoperative care ($5883-$26,035). Incremental cost-effectiveness ratio calculations noted operative treatment over nonoperative treatment for spondylolisthesis ($59,487-$115,600) per quality-adjusted life year. However, cost for patients without spondylolisthesis varied greatly from nonoperative treat dominating to $77,600 per quality-adjusted life year favoring surgery. Because the articles had heterogeneous methods and patient population, conclusion differed greatly on cost assessment. Limited quality data exist on cost-effective treatment of degenerative lumbar spinal conditions, despite more recent interest related to this topic. It is important that future research efforts focus on constructing higher quality trials in this area to help determine the most cost-effective care. 3.

Prospective analysis of adverse events in surgical treatment of degenerative spondylolisthesis

Background contextSurgical adverse event (AE) monitoring is imprecise, of uncertain validity, and tends toward underreporting. Reports focus on specific procedures rather than outcomes in the context of presenting diagnosis. Specific intraoperative (intraop) or postoperative (postop) AEs that may be independently associated with degenerative spondylolisthesis (DS) have never been reported. PurposeThe primary purpose was to assess the AE profile of surgically treated patients with L4–L5 DS. The secondary goal was to identify potential risk factors that correlate with those AEs. Study design/settingProspective cohort and academic quaternary spine center. Patient sampleNinety-two patients with L4–L5 DS were treated surgically, discharged from Vancouver General Hospital between January 1, 2009 and December 31, 2010. Outcome measuresIncidence rates and odds ratios. MethodsProspective AE data were analyzed using univariate analyses, forward selection regression models, and Spearman correlation coefficients. Results were compared with outcomes reported in the Spine Patient Outcomes Research Trial. ResultsNo AEs were seen in 57.6% of patients, one AE in 17.4%, and two or more AEs in 17.4%. Dural tears (6.5%) and intraop bone-implant interface failure requiring revision (3.3%) were the most common intraop AEs. Postoperatively, the most frequent AEs were urinary tract infection (10.9%), delirium (5.4%), neuropathic pain (4.4%), deep wound infection (3.3%), and superficial wound infection (3.3%). The odds of an intraop AE increased by 9% (95% confidence interval [CI] 1–18) per year of age at admission. Adjusted Charlson comorbidity index (CCI) did not correlate with number of AEs experienced. The odds of postop delirium correlated with CCI (odds ratio [OR] 3.39, 95% CI 1.12–10.24) and dural tear (OR 35.84, 95% CI 1.72–747.45). Length of stay was statistically significant and was influenced by two or more AEs, CCI, postop loss of correction, cerebrospinal fluid leak, deep wound infection, noninfected wound drainage, and gender. ConclusionsRisk of intraop AEs, but not postop AEs, increased with increasing age. Having multiple comorbidities does not predispose to more AEs. Infections predominate among the postop AEs. Patients at increased risk of delirium or of having an increased length of hospital stay may more easily be predicted. Studies specifically designed to prospectively assess AEs have the potential to more accurately identify postop AE rates.

Degenerative Spondylolisthesis Does Not Affect the Outcome of Unilateral Laminotomy With Bilateral Decompression in Patients With Lumbar Stenosis

Prospective subcohort study. To determine whether preoperative presence of degenerative spondylolisthesis worsens the outcome of patients undergoing unilateral laminotomy with bilateral decompression for lumbar stenosis. The standard surgical treatment for degenerative spondylolisthesis with lumbar stenosis is lumbar fusion after standard laminectomy. Although this strategy is widely adopted, it is not supported by class I evidence. This strategy assumes that degenerative spondylolisthesis worsens the outcome of laminectomy by causing postoperative instability. However, instability may be reduced or prevented by the use of less invasive decompression techniques. To test the hypothesis that preoperative degenerative spondylolisthesis worsens the outcome of less invasive lumbar decompression, we performed a prospective cohort study of 165 consecutive patients who underwent unilateral laminotomy with bilateral decompression at our institution. The patients were prospectively followed with a standardized questionnaire, 36-Item Short Form Health Survey, and standing lumbar radiographs for a maximum follow-up period of 5 years. According to the presence or absence of degenerative spondylolisthesis, the patients were divided into 2 groups: an olisthesis group and a nonolisthesis group. The average 36-Item Short Form Health Survey physical score and bodily pain score improved substantially immediately after surgery. This improvement was maintained up to 5 years postoperatively. Progression of slippage was uncommon in both groups, with an overall incidence of 8% at 5 years of follow-up. There was no significant difference in the average physical score, the bodily pain score, or the rate of progression of slippage between the olisthesis and nonolisthesis groups. Our study thus indicates that preoperative degenerative spondylolisthesis does not worsen the outcome of patients with lumbar stenosis undergoing unilateral laminotomy with bilateral decompression. These results suggest that lumbar fusion is often unnecessary in patients with degenerative spondylolisthesis and lumbar stenosis if the posterior decompression technique is unilateral laminotomy with bilateral decompression. 2.