Radiographic Adjacent Segment Disease Research Articles

Vertebral Bone Quality Score as a Predictor of Adjacent Segment Disease After Lumbar Interbody Fusion.

With lumbar spine fusion being one of the most commonly performed spinal surgeries, investigating common complications such as adjacent segment disease (ASD) is a high priority. To the authors' knowledge, there are no previous studies investigating the utility of the preoperative magnetic resonance imaging-based vertebral bone quality (VBQ) score in predicting radiographic and surgical ASD after lumbar spine fusion. We aimed to investigate the predictive factors for radiographic and surgical ASD, focusing on the predictive potential of the VBQ score. A single-center retrospective analysis was conducted of all patients who underwent 1-3 level lumbar or lumbosacral interbody fusion for lumbar spine degenerative disease between 2014 and 2021 with a minimum 12 months of clinical and radiographic follow-up. Demographic data were collected, along with patient medical, and surgical data. Preoperative MRI was assessed in the included patients using the VBQ scoring system to identify whether radiographic ASD or surgical ASD could be predicted. A total of 417 patients were identified (mean age, 59.8 ± 12.4 years; women, 54.0%). Eighty-two (19.7%) patients developed radiographic ASD, and 58 (13.9%) developed surgical ASD. A higher VBQ score was a significant predictor of radiographic ASD in univariate analysis (2.4 ± 0.5 vs 3.3 ± 0.4; P < .001) and multivariate analysis (odds ratio, 1.601; 95% CI, 1.453-1.763; P < .001). For surgical ASD, a significantly higher VBQ score was seen in univariate analysis (2.3 ± 0.5 vs 3.3 ± 0.4; P < .001) and served as an independent risk factor in multivariate analysis (odds ratio, 1.509; 95% CI, 1.324-1.720; P < .001). We also identified preoperative disk bulge and preoperative existence of adjacent segment disk degeneration to be significant predictors of both radiographic and surgical ASD. Furthermore, 3-level fusion was also a significant predictor for surgical ASD. The VBQ scoring system might be a useful adjunct for predicting radiographic and surgical ASD.

Risk factors of adjacent-segment disease after short-segment fusion in patients with de novo degenerative lumbar scoliosis.

Short-segment fusion (SSF) is an effective surgical option for appropriately selected patients with de novo degenerative lumbar scoliosis (DNDLS). Considering that DNDLS is frequently accompanied by multisegment degeneration and potential instability across the entire lumbar segments, it is inevitable that unhealthy segments remain after SSF, thereby increasing the potential risk of adjacent-segment disease (ASD) occurrence. Therefore, the authors aimed to identify the risk factors for ASD in patients with DNDLS who underwent SSF. This retrospective study included 80 patients with DNDLS (Cobb angle > 10°) who underwent SSF (1 or 2 levels) between December 2010 and July 2018 with a minimum follow-up duration of 5 years. The participants were divided into two groups: ASD and non-ASD. ASD was defined as clinical ASD rather than radiographic ASD. Various patient and operative variables were compared between the groups. Global and regional radiographic parameters (preoperatively and postoperatively) were also compared between the two groups using plain radiography and MRI. Consequently, univariate and multivariate analyses were conducted to identify the risk factors for ASD occurrence. The receiver operating characteristic (ROC) curve was used to calculate the cutoff values. The mean ± SD age was 67.7 ± 7.2 years at the time of SSF, and there were 62 women (77.5%) enrolled in the study. Thirty patients (37.5%) were in the ASD group and 50 patients (62.5%) were in the non-ASD group. The mean time from the surgery to ASD diagnosis was 34.9 ± 28.2 months in ASD group. Thirteen patients required revision surgery at a mean time of 8.8 ± 7.0 months after ASD occurrence. Multivariate logistic regression analysis demonstrated that preoperative disc wedging angle (OR 1.806, 95% CI 1.255-2.598, p = 0.001), presence of facet tropism (defined as ≥ 10° difference between the facet joint angles of the right and left sides) (OR 5.534, 95% CI 1.528-20.040, p = 0.009), and foraminal stenosis ≥ grade 2 (OR 5.935, 95% CI 1.253-28.117, p = 0.025) were significant risk factors for ASD development. The cutoff value of the preoperative disc wedging angle was calculated to be 2.5° using the ROC curve. Preoperative disc wedging angle ≥ 2.5°, presence of facet tropism, and foraminal stenosis ≥ grade 2 were identified as significant risk factors for ASD development after SSF in patients with DNDLS.

Risk Factors for Adjacent Segment Disease Following Anterior Cervical Discectomy and Fusion with Plate Fixation: A Systematic Review and Meta-Analysis.

Adjacent segment disease (ASD) following anterior cervical discectomy and fusion with plating (ACDF-P) may yield a poor prognosis or reoperation. This review aimed to summarize risk factors for radiographic ASD (RASD) and clinical ASD (CASD) after ACDF-P. Six electronic databases were searched from inception to October 30, 2021. Four reviewers independently screened titles, abstracts, and full-text articles to identify relevant studies. Methodological quality of the included studies was evaluated. Meta-analyses for risk factors were conducted, if possible. Sixteen cohort and 3 case-control studies (3,563 participants) were included. These studies showed low (n = 2), moderate (n = 9), and high (n = 8) risk of bias. One risk factor for RASD was pooled for 2 meta-analyses based on the follow-up period. Four different risk factors for CASD at ≥4 years were pooled for meta-analyses. Limited evidence showed that multi-level fusion, greater asymmetry in total or functional cross-sectional area of the cervical paraspinal muscle, and preoperative degeneration in a greater number of segments were associated with a higher RASD incidence <4 years after ACDF-P. In contrast, no significant risk factors were identified for CASD <4 years after ACDF-P. At ≥4 years after ACDF-P, limited evidence supported that both cephalad and caudal plate-to-disc distances of <5 mm were associated with a higher RASD incidence, and very limited evidence supported that developmental canal stenosis, preoperative RASD, unfused C5-C6 or C6-C7 adjacent segments, use of autogenous bone graft, and spondylosis-related ACDF-P were associated with a higher CASD incidence. Although several risk factors for RASD and CASD development after ACDF-P were identified, the supporting evidence was very limited to limited. Future prospective studies should extend the existing knowledge by more robustly identifying risk factors for RASD and CASD after ACDF-P to inform clinical practice. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Short Review/Perspective on Adjacent Segment Disease (ASD) Following Cervical Fusion Versus Arthroplasty.

Background: Although the incidence of radiographic Adjacent Segment Disease (ASD) following anterior cervical diskectomy/fusion (ACDF) or cervical disc arthroplasty (CDA) typically ranges from 2-4%/year, reportedly fewer patients are symptomatic, and even fewer require secondary surgery.Methods: Multiple studies have documented a 2-4% incidence of radiographic ASD following either ACDF or CDA per year. However, fewer are symptomatic from ASD, and even fewer require additional surgery/reoperations.Results: In a meta-analysis (2016) involving 83 papers, the incidence of radiographic ASD per year was 2.79%, but symptomatic disease was present in just 1.43% of patients with only 0.24% requiring secondary surgery. In another study (2019) involving 38,149 patients undergoing ACDF, 2.9% (1092 patients; 0.62% per year) had radiographic ASD within an average of 4.66 postoperative years; the younger the patient at the index surgery, the higher the reoperation rate (i.e. < 40 years of age 4.56 X reoperations vs. <70 at 2.1 X reoperations). In a meta-analysis of 32 articles focusing on ASD 12–24 months following CDA, adjacent segment degeneration (ASDeg) occurred in 5.15% of patients, but adjacent segment disease (AS Dis) was noted in just 0.2%/ year. Further, AS degeneration occurred in 7.4% of patients after 1-level vs. 15.6% following 2 level fusions, confirming that CDA’s “motion-sparing” design did not produce the “anticipated” beneficial results.Conclusion: The incidence of radiographic ASD ranges from 2-4% per year for ACDF and CDA. Additionally, both demonstrate lesser frequencies of symptomatic ASD, and the need for secondary surgery. Further, doubling the frequency of ASD following 2 vs. 1-level CDA, should prompt surgeons to limit surgery to only essential levels.

Comparison of minimally invasive and open TLIF outcomes with more than seven years of follow-up

BackgroundFew studies directly comparing minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) and open TLIF offering long-term follow-up data have been performed to date. Therefore, we sought to compare mid- to long-term outcomes between these two surgical approaches. MethodsThis was a retrospective data analysis of two surgical groups. We analyzed the details of 97 patients with degenerative lumbar disease who were treated with MI TLIF (n = 55) or open TLIF (n = 42) between 2011–2014 and had at least seven years of follow-up data available. Peri- and postoperative outcomes were compared. To evaluate rates of adjacent segment disease (ASD) and revisions, frequencies of radiologic, symptomatic, and operative ASD were analyzed accordingly. ResultsIn terms of clinical outcome, the Oswestry Disability Index and visual analog scale scores were significantly reduced, with no difference between the groups. However, data for several peri- and postoperative outcomes, including perioperative blood loss, ambulation day, hospital stay, and operation time, varied in a manner favoring the MI TLIF group (P < 0.05). Rates of radiologic ASD and symptomatic ASD were significantly higher in the open TLIF group beginning at five years of follow-up (P < 0.05), while the rate of operative ASD and the revision rate were similar between the groups. Other long-term outcomes, including fusion rate and complications, remained similar between the two groups at 7 years. ConclusionPatients undergoing MI TLIF showed favorable immediate postoperative outcomes and less radiographic ASD. However, the rates of fusion and operative ASD remained similar between the two groups after 7 years of follow-up.

Interspinous Process Fixation Device Versus Extended Pedicle Screw Fixation for Symptomatic Adjacent Segment Disease: 3-Year Retrospective Study

In the present study, we compared the clinical and radiographic outcomes of an interspinous process fixation device (IFD) with those of extended pedicle screw fixation (PSF) for symptomatic adjacent segment disease (ASD) after lumbar fusion. The data from 109 patients with ASD treated with IFD (n= 48) or extended PSF (n= 61) from January 2009 to January 2016 were reviewed retrospectively. The clinical outcomes were measured using a visual analog scale (VAS) and the Oswestry disability index. The radiographic outcomes included the fusion rate, incidence of cage subsidence, and additional radiographic ASD. The mean incision length, operative time, blood loss, and length of hospital stay were significantly lower in the IFD group (P < 0.001). Postoperative back and leg pain were relieved in both groups (P < 0.001). The mean preoperative VAS scores were 8.3 ± 1.3 and 8.5 ± 1.1 in the IFD and PSF groups and had improved to 2.8 ± 1.1 and 2.7 ±1.2 after 36 months, respectively (P < 0.001). At 36 months postoperatively, 10 of the 56 patients (17.9%) in the PSF group had developed additional radiographic ASD compared with 2 of 44 patients (4.5%) in the IFD group. Our results have demonstrated that in the treatment of symptomatic ASD, comparable clinical and radiologic outcomes can be achieved using IFD, which has a shorter skin incision, shorter operative time, less intraoperative blood loss, and shorter hospital stay than the extended PSF technique. Although not statistically significant, the IFD resulted in a lower ASD incidence compare with the PSF technique. Thus, IFD might be an alternative surgical method for symptomatic ASD after lumbar spine fusion.

Influence of comorbid knee osteoarthritis on surgical outcome and sagittal spinopelvic/lower-extremity alignment in elderly patients with degenerative lumbar spondylolisthesis undergoing transforaminal lumbar interbody fusion.

This retrospective study aimed to clarify the influence of comorbid severe knee osteoarthritis (KOA) on surgical outcome in terms of sagittal spinopelvic/lower-extremity alignment in elderly patients with degenerative lumbar spondylolisthesis (DLS). In total, 110 patients aged at least 65 years (27 men, 83 women; mean age 74.0 years) who underwent short-segment lumbar fusion were included in the present study. Using the Kellgren-Lawrence (KL) grading system, patients were categorized into those with no to mild KOA (the mild-OA group: KL grades 0-2), moderate KOA (moderate-OA group: KL grade 3), or severe KOA (severe-OA group: KL grade 4). Surgical results were assessed using the Japanese Orthopaedic Association (JOA) scoring system, and spinopelvic/lower-extremity parameters were compared among the 3 groups. Adjacent-segment disease (ASD) was assessed over a mean follow-up period of 4.7 years (range 2-8.1 years). The study cohort was split into the mild-OA group (42 patients), the moderate-OA group (28 patients), and the severe-OA group (40 patients). The severe-OA group contained significantly more women (p = 0.037) and patients with double-level listhesis (p = 0.012) compared with the other groups. No significant differences were found in mean postoperative JOA scores or recovery rate among the 3 groups. The mean postoperative JOA subscore for restriction of activities of daily living was only significantly lower in the severe-OA group compared with the other groups (p = 0.010). The severe-OA group exhibited significantly greater pelvic incidence, pelvic tilt, and knee flexion angle (KFA), along with a smaller degree of lumbar lordosis than the mild-OA group both pre- and postoperatively (all p < 0.05). Overall, the rate of radiographic ASD was observed to be higher in the severe-OA group than in the mild-OA group (p = 0.015). Patients with ASD in the severe-OA group exhibited significantly greater pelvic tilt, pre- and postoperatively, along with less lumbar lordosis, than the patients without ASD postoperatively (all p < 0.05). A lack of lumbar lordosis caused by double-level listhesis and knee flexion contracture compensated for by far greater pelvic retroversion is experienced by elderly patients with DLS and severe KOA. Therefore, corrective lumbar surgery and knee arthroplasty may be considered to improve sagittal alignment, which may contribute to the prevention of ASD, resulting in favorable long-term surgical outcomes.

Risk factors related to adjacent segment degeneration: retrospective observational cohort study and survivorship analysis of adjacent unfused segments

Object: Adjacent segment disease (ASD) has been described as a frequent complication after a lumbar spinal fusion procedure, though its incidence and the factors related to its appearance are not well established. The radiographic signs that identify ASD in unfused segments may be a consequence of biomechanical changes induced by the fusion procedure. This study sought to analyse the incidence of radiographic changes (radiographic ASD) in all adjacent unfused segments, the clinical changes that require a second procedure (clinical ASD), and the risk factors of their appearance evaluated at different follow-up times.Methods: We conducted a retrospective cohort study of patients fused for degenerative spine disease and instability to analyse ASD risk factors using actuarial estimation, comparison of the Kaplan-Meier survival curves of each variable, and Cox proportional-hazards regression analysis.Results: Among the 263 patients included in the study, radiographic changes were observed in 57.4% and related clinical changes in 20.2%. The univariate analysis showed a higher risk of ASD in patients with smaller post- vs. pre-operative lumbar lordosis (p = .018), diagnosis of lumbar canal stenosis (p = .019), fusion of three or more vs. fewer levels (p = .009) and those fixed with top-loading screws vs. side-connecting screws (p = .001). Cox proportional-hazards regression analysis showed that the use of top-loading pedicle screws and three or more levels of fusion led to a 3- and 2-fold higher risk of degeneration in adjacent unfused segments respectively.Conclusions: Risk of a second surgical procedure due to clinical changes is 3-fold higher in patients with three or more levels of fusion, and 2.5-fold higher in patients intervened with top-loading pedicle screws.

Friday, September 28, 2018 10:30 AM–12:00 PM abstracts: complications of cervical spine surgery: 163. Sagittal alignment parameters associated with adjacent segment pathology after anterior cervical discectomy and fusion

BACKGROUND CONTEXT Changes in the cervical alignment from preoperative to postoperative may alter cervical spine mechanics, and increase the rate of early adjacent segment pathology. Correction and restoration of cervical sagittal alignment is crucial in achieving a successful result after an ACDF and potentially decreasing the risk of developing ASD. PURPOSE We sought to evaluate the relationship between cervical spine sagittal alignment and adjacent segment disease (ASD) following anterior cervical discectomy and fusion (ACDF) as determined by radiographic and clinical outcomes. STUDY DESIGN/SETTING Retrospective Cohort Series. PATIENT SAMPLE Patients undergoing ACDF from 2008 to 2015 who developed radiographic signs of ASD(+) were identified and compared to a matched group of ACDF patients who did not develop radiographic evidence of ASD(−) for a period of at least 1 year. Patients were excluded from analysis if they were under 18 years of age at the time of surgery, had postoperative follow up less than 12 months or had an ACDF for cervical spine fracture or infection. OUTCOME MEASURES The number or location of levels fused was recorded and radiographs were reviewed preoperatively, immediately postoperative, and at final follow up. The sagittal parameters measured included change in C2-C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis. Patient reported outcomes were obtained in the form of Neck Disability Index (NDI) scores and Visual Analog Scales (VAS) scores for the neck and arm. Radiographic diagnosis of ASD was determined by the presence of new or enlarged osteophytes, endplate sclerosis, disc space narrowing g50%, and/or increased calcification of the anterior longitudinal ligament (ALL) as presented by previous published studies. METHODS Radiographic diagnosis of ASD was determined by the presence of new or enlarged osteophytes, endplate sclerosis, disc space narrowing g50%, and/or increased calcification of the anterior longitudinal ligament (ALL) as presented by previous published studies. Baseline patient characteristics were compared using chi-squared analysis and independent sample t-tests for categorical and continuous data, respectively. Bivariate and multivariate regressions were subsequently used to compare clinical outcomes between procedure groups. Multivariate analyses controlled for differences in baseline patient characteristics. RESULTS A total of 101 ASD(+) patients were identified having underwent ACDF from 2008 to 2015 and compared to 131 ASD(−). The ASD(−) were free of ASD for a period of at least 1 year. The groups were similar with regard to demographic and surgical variables, but with a predominance of males in the ASD group 61.2% (p=.001). Rigid plates were used in 42% of all constructs and were more represented in the ASD(−) than ASD(+) group (48% vs. 33%, respectively, p=.017). The most common levels included in the fusion were C5-7 (28%). For all patients, preoperative lordosis was increased from 4.8p11.4° to 7.9p10.2° postoperatively and improved to 9.4p9.9° at final followup. Patients with greater kyphosis throughout the cervical spine at final followup had increased odds of developing ASD (OR 0.97 per degree, p=.040). Patients with greater preoperative kyphosis through the planned fusion segment had increased odds of ASD (OR 0.93 per degree, p=.003). Patients who lost lordosis through the fusion from initial postop to final followup had greater odds of developing ASD (OR 0.85 per degree, pl0.001). Patients who had greater change in preoperative to postoperative fusion segment lordosis were found to exhibit a greater risk of ASD (OR 1.06 per degree, p=0.019). The SVA and T1 slope angles did not change substantially from preoperative to postoperative and there were no differences between ASD groups. The mean postoperative and final proximal and distal segment lordosis was also not different between groups except for significantly less proximal adjacent segment lordosis in ASD patients at final follow-up (0.2p5.0 vs. 1.4p4.4; p=.026). There were no significant differences between preoperative, postoperative, or change in patient reported outcome surveys in patients with or without signs of radiographic ASD. CONCLUSIONS Patients with a greater preoperative cervical kyphosis and kyphosis through the proposed fusion segment may have greater odds of develeoping radiographic adjacent segment degeneration. Similarly, those that had a greater greater correction of cervical lordosis postoperatively, and those who loss lordosis at the fusion segment also presented with increased odds of developing adjacent segment degeneration. Our results suggest that preoperative and postoperative measures of cervical spine alignment, specifically related to C2-C7 and fusion segment lordosis, may predict the development of radiographic signs of adjacent level pathology following an ACDF.

Low incidence of adjacent segment disease after posterior lumbar interbody fusion with minimum disc distraction: A preliminary report.

Study Design:A retrospective review of prospectively collected data.Objective:To investigate the incidence of radiographic and symptomatic adjacent segment disease (ASD) and identify possible risk factors for ASD after posterior lumbar interbody fusion (PLIF) with minimum disc distraction by selecting low-height interbody cages.Summary of Background Data:Excessive disc space distraction is reportedly 1 of the risk factors for ASD after PLIF; however, the incidence and other risk factors of ASD after PLIF with minimum disc distraction remain unclear.Methods:Forty-one consecutive patients who underwent PLIF at L4-L5 and were postoperatively followed up for a minimum of 2 years were included. The height and shape (box or bullet shape) of interbody cages was determined according to the disc height and morphology of the intervertebral space assessed on preoperative computed tomography scans to avoid excessive distraction. The incidence of radiographic and symptomatic ASD was evaluated and all demographic and radiographic parameters were compared between patients with and without ASD. Multivariate logistic regression analysis was performed to identify risk factors for ASD among the variables with P < .20 in univariate analysis.Results:The overall incidence of ASD was 12.2% (5/41 patients): radiographic ASD, 7.3% (3 patients); symptomatic ASD, 4.9% (2 patients). Multivariate analysis revealed preoperative retrolisthesis of L3 on extension as the sole risk factor for ASD after PLIF with minimum disc distraction (odds ratio, 2.13; 95% confidence interval, 1.00–4.05; P = .049).Conclusions:The incidence of ASD in this study was lower than that of ASD in our previous study about PLIF with distraction of disc space (12.2% vs. 31.8%). Minimum disc distraction by selection of low-height interbody cages is a simple and effective method to prevent ASD at the surgeons’ discretion, although preexisting retrolisthesis at the adjacent upper segment should be taken into consideration.

Adjacent level disease-background and update based on disc replacement data.

The precise etiology of adjacent segment disease following cervical spine surgery is controversial. Theories for development include inevitable changes secondary to the natural progression of the degenerative cascade and changes secondary to altered biomechanics of the fused cervical spine. Motion preserving techniques, such as cervical disc arthroplasties (CDA), have been introduced with the hopes of reducing the rates of adjacent segment pathology. Recently, 7-year data from the investigational device exemption (IDE) studies have been published. The purpose of this review is to provide an update on cervical adjacent segment disease incorporating this emerging data into the analysis. Although the 7-year data for CDA has confirmed continued success, specifically regarding improved neck pain and reduced re-operation rates, the influence of CDA on reducing rates of adjacent segment pathology remains questionable. Although some studies have found more radiographic adjacent segment disease after anterior cervical discectomy and fusion (ACDF) compared to CDA, an association between these findings and clinical symptoms has not been established. Cervical disc arthroplasty continues to outperform cervical disc fusion regarding some patient specific parameters, however, whether CDA reduces rates of radiographic and clinical adjacent segment pathology remains unknown. Without studies developed specifically to address this question, the answer remains elusive.

Risk Factors of Adjacent Segment Disease After Transforaminal Inter-Body Fusion for Degenerative Lumbar Disease.

A retrospective study. The purpose of this study was to determine the incidence and risk factors of adjacent segment disease (ASD) after transforaminal inter-body fusion (TLIF) for degenerative lumbar disease. ASD is a major complication after spinal fusion. Many reports have been published concerning the risk factors for ASD after TLIF. A number of quantitative relationships to spino-pelvic parameters have been established. A retrospective cohort study was carried out to investigate spino-pelvic alignment in patients with ASD after TLIF. This study evaluated 263 subjects (150 subjects undergoing floating fusion (FF group), and 113 patients undergoing lumbosacral fusion (LF group)) who underwent TLIF from 2009 to 2012. The mean follow-up period was 37.6 months. Several parameters were measured using pre- and postoperative full-length free-standing radiographs, including lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), pelvic tilt (PT), and PI-LL. Multivariate logistic regression analysis was performed to evaluate these parameters as potential risk factors of early onset radiographic ASD. Radiographic ASD was found in 65 cases (43.3%) in the FF group, and 49 cases (43.3%) in the LF group. LL improved by 7.5° and 3.9° in each group respectively after TLIF. However, PT worsened by 6.4° in the LF group. When comparing with ASD positive cases and ASD negative cases, a significant difference in preoperative PT was observed in both FF (P = 0.001) and LF groups (P = 0.0001). Logistic regression analysis and receiver operating characteristic analysis revealed that preoperative PT of more than 22.5° was a significant risk factor of the incidence of ASD after TLIF (P = 0.02; odds ratio: 5.1, 95% CI: 1.62-9.03). Patients with preoperative sagittal imbalance have a statistically significant increased risk of ASD. The risk of ASD incidence was 5.1 times greater in subjects with preoperative PT of more than 22.5°.

Patient Outcomes Following Posterior Lumbar Interbody Fusion for Adjacent Segment Disease Using VariLift® as a Standalone Expandable Interbody Device

Background: Adjacent Segment Disease (ASD) is a notable complication following lumbar fusion surgery. Clinicians use various surgical techniques to correct the progression of spine deterioration and reduce the risk of continued ASD. The aim of this retrospective case series is to describe patient outcomes following posterior lumbar interbody fusion (PLIF) using the VariLift® standalone interbody device (without supplemental fixation) for the treatment of ASD. Methods: Nine consecutive patients who underwent a single-level PLIF for the treatment of ASD were reviewed. Outcome measures included patient demographics, comorbidities, surgical complications, time to fusion, Visual Analog Scales for Pain (VAS), and overall patient reported recovery of symptoms. Nine patients (8 males, 1 female) with a mean age of 62.3 (42 to 72) years underwent a single-level procedure. The standalone VariLift interbody fusion system was used in all 9 sequential patients, regardless of the type of fusion/fixation instrumentation previously used. Surgical technique consisted of discectomy and generous bilateral laminotomies with medial facetectomies preserving midline ligamentous structures. Results: Radiographic ASD was confirmed in all cases. Each patient had a history of a lumbar fusion. Preoperatively, 89% of patients reported 9-10 VAS back pain levels. All patients experienced symptomatic improvement. By 12 months postoperatively, average VAS back pain score was 2, a significant improvement from baseline (p<0.05). Solid interbody fusion without implant failure was observed in all cases with averaged time to fusion at 346 days (min=181 days). Conclusion/level of evidence: Posterior lumbar interbody fusion using the VariLift device to treat symptomatic ASD offers significant clinical success and solid fusion rates without the need for supplemental fixation or extension of previous supplemental fixation. Level of evidence IV. Clinical relevance: This stand-alone fusion device produced high fusion rates and symptomatic improvement in a sample of patients with severe back pain and ASD.

Clinical and radiological outcome after anterior cervical discectomy and fusion with stand-alone empty polyetheretherketone (PEEK) cages

To evaluate long-term results after one-, two-, and three-level anterior cervical discectomy and fusion (ACDF) with stand-alone empty polyetheretherketone (PEEK) cages. We performed a retrospective review of a consecutive patient cohort that underwent ACDF with stand-alone empty PEEK cages between 2007 and 2010 with a minimum follow-up of 12 months. Radiographic follow-up included static and flexion/extension radiographs. Changes in the operated segments were measured and compared to radiographs directly after surgery. Clinical outcome was evaluated by a physical examination, pain visual analog scale (VAS), and health-related quality of life (HRQL) using the EuroQOL questionnaire (EQ-5D). Analysis of associations between fusion, subsidence, cervical alignment, and clinical outcome parameters were performed. Of 407 consecutive cases, 318 met all inclusion criteria. Follow-up data were obtained from 265 (83 %) cases. The mean age at presentation was 55 years and 139 patients were male (52 %). In the sample, 127, 125, and 13 patients had one-, two-, and three-level surgeries, respectively; 132 (49 %) presented with spondylotic cervical myelopathy and 133 (50 %) with cervical radiculopathy. Fusion was achieved in 85, 95, and 94 % of segments in one-, two-, and three-level surgeries, respectively. Non-fusion was associated with higher VAS pain levels. Radiographic adjacent segment disease (ASD) was observed in 20, 29, and 15 % in one-, two-, and three-level surgeries, respectively. ASD was associated with lower HRQL. Subsidence was observed in 25, 27, and 15 % of segments in one-, two-, and three-level surgeries, respectively. However, this had no influence on clinical outcome. Follow-up operations for symptomatic adjacent disc disease and implant failure at index level were needed in 16 (6 %) and four (1.5 %) cases, respectively. Younger age was associated with better clinical outcome. Multilevel surgery favored better myelopathy outcomes and fusion reduced overall pain. ASD worsened EuroQOL-Index values. Worsening of the cervical alignment induced arm pain. One- and two-level ACDF with stand-alone empty PEEK cages achieved very high fusion rates and a low rate of follow-up operations. The rate of good clinical outcome is highly satisfactory. Younger age was the single most influential factor associated with better clinical outcome.

Does pre-existing L5-S1 degeneration affect outcomes after isolated L4-5 fusion for spondylolisthesis?

BackgroundConcerns have been raised regarding residual symptoms of caudal segment (L5-S1) degeneration that may affect clinical outcomes or require additional surgery after isolated L4-5 fusion, especially if there is pre-existing L5-S1 degeneration. This study aimed to evaluate the L5-S1 segment after minimally invasive lumbar interbody fusion at the L4-5 segment, as well as the influence of pre-existing L5-S1 degeneration on radiologic and clinical outcomes.MethodsThis retrospective study evaluated patients with isthmic spondylolisthesis and degenerative spondylolisthesis who underwent mini-open anterior lumbar interbody fusion with percutaneous pedicle screw fixation (PSF) or minimally invasive transforaminal interbody fusion with PSF at the L4-5 segment. The minimum follow-up period was 7 years, and radiographic evaluations were conducted via magnetic resonance imaging, computed tomography, and plain radiography at the 5-year follow-up. Clinical outcomes were assessed using the Visual Analog Score, Oswestry Disability Index, and surgical satisfaction rate. Patients were divided into two groups, those with and without pre-existing L5-S1 degeneration, and their final outcomes and incidence of radiographic and clinical adjacent segment disease (ASD) were compared.ResultsAmong 70 patients who underwent the procedures at our institution, 12 (17.1%) were lost to follow-up. Therefore, this study evaluated 58 patients, with a mean follow-up period of 9.4 ± 2.1 years. Among these patients, 22 patients had pre-existing L5-S1 degeneration, while 36 patients did not have pre-existing L5-S1 segmental degeneration. There were no significant differences in the clinical outcomes at the final follow-up when the two groups were compared. However, radiographic ASD at L5-S1 occurred in seven patients (12.1%), clinical ASD at L5-S1 occurred in three patients (5.2%), and one patient (1.7%) required surgery. In the group with pre-existing degeneration, L5-S1 degeneration was radiographically accelerated in four patients (18.2%) and clinical ASD developed in one patient (4.5%). In the group without pre-existing degeneration, L5-S1 degeneration was radiographically accelerated in three patients (8.3%) and clinical ASD developed in two patients (5.7%). There were no differences in the incidence of ASD when we compared the two groups.ConclusionsPre-existing L5-S1 degeneration does not affect clinical and radiographical outcomes after isolated L4-5 fusion.

Combined Dynamic and Rigid Multilevel Posterolateral Lumbar Fixation Systems in Prevention of Adjacent Segment Disease

Introduction: The gold standard in the treatment of lumbar degenerative spinal diseases is the posterolateral fusion with rod and screws. Semi-rigid systems were first designed to stabilize the abnormal segment and to unload degenerated discs and facet joints. One commonly observed consequence of fusing spinal motion levels has been adjacent segment disease (ASD). Due to prevention of ASD is a complicated and controversial topic, the aim of this study was to assess the role of combined dynamic and rigid posterolateral fixation systems in prevention of ASD. Patients and Methods: A total of 76 adult patients with various lumbar spine pathologies, treated with posterior fusion and pedicle screw fixation between T12 and sacrum were included in this study. The prevalence of radiological and clinical ASD was measured and the functional outcome of the patients was evaluated using the Oswestry questionnaire. Results: Evidence of radiographic ASD was noted in 6 of the 76 patients (7.9%), of whom one patient was symptomatic (16.67%). The mean preoperative Oswestry score was 27.2 ± 20.7 and the mean postoperative Oswestry score was 15.4 ± 20.3. There was a significant difference between the 2 scores (p=0.027). The mean postoperative lumbar lordosis was -53° ± 2.08 and the pelvic incidence 61° ± 3.12. Related to the complications, 6 patients with superficial wound infections, one patient with deep venous thrombosis (DVT), and one patient with ASD were reported. Discussion: In our study, the very low incidence of ASD is achieved by the mean of preservation of the top facet joint, correction and preservation of coronal and sagittal balance, preservation of motion in the lumbar spine with the use of semi-rigid devices, and early rehabilitation accompanying by the training of the patient regarding to the body balance. Semi-rigid fixation significantly reduces the risk of screw fracture by the absorption of the stress on the interpedicular damper and enhances the bone fusion by maintaining constraints on the cages which remain under a compressive load.

Cervical artificial disc replacement with ProDisc-C: Clinical and radiographic outcomes with long-term follow-up

Cervical artificial disc replacement (ADR) is indicated for the treatment of severe radiculopathy permitting neural decompression and maintenance of motion. We evaluated the clinical and radiographic outcomes in cervical ADR patients using the ProDisc-C device (DePuy Synthes, West Chester, PA, USA) with a 5–9year follow-up. Data were collected through a prospective registry, with retrospective analysis performed on 24 consecutive patients treated with cervical ADR by a single surgeon. All patients underwent single- or two-level ADR with the ProDisc-C device. Outcome measures included neck and arm pain (visual analogue scale), disability (neck disability index [NDI]), complications and secondary surgery rates. Flexion-extension cervical radiographs were performed to assess range of motion (ROM) of the device and adjacent segment disease (ASD). Average follow-up was 7.7years. Neck and arm pain improved 60% and 79%, respectively, and NDI had an improvement of 58%. There were no episodes of device migration or subsidence. Mean ROM of the device was 6.4°. Heterotopic ossification was present in seven patients (37%). Radiographic ASD below the device developed in four patients (21%) (one single-level and three two-level ADR). No patient required secondary surgery (repeat operations at the index level or adjacent levels). Fourteen out of 19 patients (74%) were able to return to employment, with a median return to work time of 1.3months. The ProDisc-C device for cervical ADR is a safe option for patients providing excellent clinical outcomes, satisfactory return to work rates and maintenance of segmental motion despite radiographic evidence of heterotopic ossification and ASD on long-term follow-up.

Congenital Stenosis and Adjacent Segment Disease in the Cervical Spine

Symptomatic adjacent segment disease (ASD) after anterior cervical fusion (ACF) is reported in 25% of patients at 10 years postoperatively. Debate continues as to whether this degeneration is due to the natural history of the disk or the changed biomechanics after ACF. This study explored whether congenital stenosis predisposes patients to an increased incidence of ASD after ACF. A retrospective review of 635 patients with myelopathy or radiculopathy was performed; 364 patients had complete records for review. Patients underwent 1- to 5-level ACF (94 one-level, 145 two-level, 79 three-level, 45 four-level, and 1 five-level). Radiographs were evaluated for bony congenital stenosis using validated parameters, and ASD was measured according to Hilibrand's criteria and correlated with symptomatic ASD. Congenital stenosis was found in 21.7% of patients and radiographic ASD in 33.5%, with a significant association between these parameters. However, symptomatic ASD occurred in 11.8% of patients; no association between congenital stenosis and symptomatic ASD or myelopathy and ASD was found. Clinical results demonstrated excellent or good Robinson scores in 86.2% of patients and Odom scores in 87% of patients. Despite mostly excellent to good outcomes, symptomatic ASD is common after ACF. Although congenital stenosis appears to increase the incidence of radiographic ASD, it does not appear to predict symptomatic ASD.

Adjacent segment disease and C-ADR: promises fulfilled?

Study design: Systematic review.Clinical question: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) in patients treated for cervical degenerative disc disease?Methods: A systematic search of MEDLINE/PubMed and bibliographies of key articles was done to identify studies with long-term follow-up for symptomatic and/or radiographic ASD comparing C-ADR with fusion for degenerative disc disease of the cervical spine. The focus was on studies with longer follow-up (48–60 months) of primary US Food and Drug Administration trials of Prestige ST, Prodisc-C, and Bryan devices as available. Trials of other discs with a minimum of 24 months follow-up were considered for inclusion. Studies evaluating lordosis/angle changes at adjacent segments and case series were excluded.Results: From 14 citations identified, four reports from three randomized controlled trials and four nonrandomized studies are summarized. Risk differences between C-ADR and ACF for symptomatic ASD were 1.5%–2.3% and were not significant across RCT reports. Time to development of ASD did not significantly differ between treatments. Rates of radiographic ASD were variable. No meaningful comparison of ASD rates based on disc design was possible. No statistical differences in adjacent segment range of motion were noted between treatment groups.Conclusion: Our analysis reveals that, to date, there is no evidence that arthroplasty decreases ASD compared with ACDF; the promise of arthroplasty decreasing ASD has not been fulfilled.

Surgical Outcomes of Degenerative Spondylolisthesis With L5–S1 Disc Degeneration

A retrospective clinical and radiographic study was performed. The purpose of this study was to compare outcomes of patients with degenerative spondylolisthesis and a preexisting degenerative L5-S1 disc treated with a lumbar floating fusion (LFF) versus lumbosacral fusion (LSF). Fusion for treatment of degenerative spondylolisthesis often ends at the L5 level. These patients usually had a preexisting L5-S1 disc degeneration; however, no literature mentions the role of prophylactic LSF in degenerative spondylolisthesis associated with L5-S1 disc degeneration. A total of 107 patients with a minimum 5-year follow-up who had lumbosacral or LFF with pedicle instrumentation for degenerative spondylolisthesis were included. UCLA (University of California, Los Angeles) classification was used to evaluate the radiographic results of the L5-S1 segment. The Oswestry Disability Index (ODI) and modified Brodsky's criteria were used to evaluate patients' clinical results. The incidence of adjacent segment disease (ASD) (includes radiographic and clinical ASD) of both ends was recorded. There were no statistically significant differences in sex, age distribution, or amount of follow-up between the LFF and LSF groups. The LSF group had a higher percentage of patients that underwent total L5 laminectomy with loss of L5-S1 posterior ligament integrity (LSF = 92% vs. LFF = 67%, P = 0.019). The higher incidence of cephalic ASD in the LSF group was statistically significant (LSF = 25% vs. LFF = 9.7%, P = 0.049). Although no patient in the LSF group developed L5-S1 ASD, need for L5-S1 segment revision surgery was not prevented with LSF. Clinical outcomes on the basis of the success rate (LFF = 85.5% vs.LSF = 70.8%, P = 0.103) and ODI difference (LFF = 28.97 ± 15.82 vs. LSF = 23.04 ± 10.97, P = 0.109), there were no statistically significant difference between these two groups. Posterior instrumentation with posterolateral LFF for the treatment of degenerative spondylolisthesis with concomitant L5-S1 disc degeneration results in a high percentage of satisfactory clinical results. Extended fusion to the sacrum did not provide a better clinical result. LSF could not reduce the incidence of revision surgery at the L5-S1 segment and involved greater incidence of cephalic ASD.