Topping-off Surgery Research Articles

The effects of topping-off instrumentation on biomechanics of sacroiliac joint after lumbosacral fusion

BackgroundLumbar/lumbosacral fusion supplemented with topping-off devices has been proposed with the aim of avoiding adjacent segment degeneration proximal to the fusion construct. However, it remains unclear how the biomechanics of the sacroiliac joint (SIJ) are altered after topping-off surgery. The objective of this study was to investigate the biomechanical effects of topping-off instrumentation on SIJ after lumbosacral fusion. MethodsThe validated finite element model of an intact lumbar spine–pelvis segment was modified to simulate L5–S1 interbody fusion fixed with a pedicle screw system. An interspinous spacer, Device for Intervertebral Assisted Motion (DIAM), was used as a topping-off device and placed between interspinous processes of the L4 and L5 segments. Range of motion (ROM), von-Mises stress distribution, and ligament strain at SIJ were compared between fusion (without DIAM) and topping-off (fusion with DIAM) models under moments of four physiological motions. ResultsROM at the left and right SIJs in the topping-off model was higher by 26.9% and 27.5% in flexion, 16.8% and 16.1% in extension, 18.8% and 15.8% in lateral bending, and 3.7% and 7.4% in axial rotation, respectively, compared to those in the fusion model. The predicted stress and strain data showed that under all physiological loads, the topping-off model exhibited higher stress and ligament strain at the SIJs than the fusion model. ConclusionsMotion, stress, and ligament strain at SIJ increase when supplementing lumbosacral fusion with topping-off devices, suggesting that topping-off surgery may be associated with higher risks of SIJ degeneration and pain than fusion alone.

The effect of interlaminar Coflex stabilization in the topping-off procedure on local and global spinal sagittal alignment

PurposeTo investigate the effect of interlaminar Coflex stabilization (ICS) at various segments in the topping-off procedure on local and global spinal sagittal alignment.MethodsEighty-nine consecutive patients with degenerative lumbar spinal stenosis (DLSS) who underwent ICS and transforaminal lumbar interbody fusion (TLIF) were retrospectively reviewed. They were divided into Group A (L4-L5 ICS + L5-S1 TLIF), Group B (L3-L4 ICS + L4-S1 TLIF), and Group C (L2-L3 ICS + L3-S1 TLIF) according to their fusion levels. The measured local sagittal parameters included the implanted segmental angle (ISA), intervertebral disc angle (IDA), intervertebral foreman height (IFH), and disc height. The assessed global sagittal parameters included thoracic kyphosis, lumbar lordosis (LL), the fused segment angle (FSA), the sacral slope, the pelvic tilt, pelvic incidence, and the sagittal vertical axis. The Oswestry Disability Index (ODI) and visual analog scales (VAS) were recorded to evaluate the clinical outcomes.ResultsRegarding the local alignment parameters, the ISA and IDA decreased immediately after surgery in Groups A and B, followed by an increase at the last follow-up (all, P < 0.05). Conversely, the IFH of Groups A and B first increased after surgery and then decreased to approximately the original value (all, P < 0.05). No significant differences were evident between the local sagittal parameters at different time points in Group C. Regarding the global sagittal profiles, the LL and FSA exhibited a significant postoperative increase (both at P < 0.05) in all the groups. All three groups displayed significant improvements in the ODI, VAS-back pain, and VAS-leg pain. Furthermore, 4.5% (4/89) of the patients exhibited radiographic adjacent segment degeneration (ASD) at the last follow-up.ConclusionICS during topping-off surgery led to a temporary loss of local lordosis, especially in the lower lumbar segment, while the intervertebral space realigned after middle-term follow-up. The topping-off procedure with ICS is a feasible and promising surgical option of DLSS since it reduces fusion levels and prevents ASD development.

Topping-off Surgery Versus Transforaminal Lumbar Intervertebral Fusion for Combined One-level Spondylolisthesis and Adjacent Lumbar Disc Herniation: A Comparative Study of Clinical Efficacy and Radiographic Outcomes With a Two-year Follow-up.

To investigate the radiographic and clinical outcomes in patients diagnosed with multilevel lumbar spine degeneration, undergoing hybrid stabilization with an interspinous device (IPD) adjacent to spine fusion, as compared with those experiencing three-segment or two-segment transforaminal lumbar interbody fusion (TLIF) via minimally invasive surgery (MIS). Between 2015-2017, 51 consecutive patients who received three-segment TLIF, interspinous dynamic stabilization combined with two-segment TLIF (topping-off surgery), and two-segment TLIF coupled with adjacent level lumbar discectomy (two-segment TLIF+discectomy) were studied. These three operative procedures were performed by one neurosurgeon at the same hospital. Post-operative analysis of the two-year analysis was conducted by another neurosurgeon. Radiographic and clinical outcomes were compared among the three groups. Duration of surgery was significantly shorter in the topping-off surgery and TLIF+discectomy compared to three-segment TLIF group. Although there was no difference in hospital stay among the three groups, visual analogue scale (VAS) and Oswestry disability index (ODI) were less in the topping-off group than in the three-segment TLIF or two-segment TLIF+discectomy groups after one week and three months follow-up, respectively. Disc high index (DHI) in adjacent segment decreased from before the operation to two years follow-up postoperatively in the two-segment TLIF+discectomy group. In contrast, DHI in the segment adjacent to spondylolisthesis increased from before the operation to last follow-up post-operatively in the three-segment TLIF group. Compared with the two-segment TLIF+discectomy group, the topping-off group showed higher foramen high index at the IPD level. While there was no difference in segment range of motion among the three groups, the topping-off group showed preserved total range of motion at a two-year follow-up, as compared with the three-segment TLIF group. Under strict indications, topping-off surgery is an acceptable alternative to fusion surgery for spondylolisthesis combined with adjacent disc degeneration.

Biomechanical investigation of topping-off technique using an interspinous process device following lumbar interbody fusion under vibration loading.

Topping-off technique has been proposed to prevent adjacent-segment degeneration/disease following spine fusion surgery. Nevertheless, few studies have investigated biomechanics of the fusion surgery with topping-off device under whole-body vibration (WBV). This biomechanical study aimed to investigate the vibration characteristics of human lumbar spine after topping-off surgery, and also to evaluate the effect of bony fusion on spine biomechanics. Based on a healthy finite-element model of lumbosacral spine (L1-sacrum), the models of topping-off surgery before and after bony fusion were developed. The simulated surgical procedures consisted of interbody fusion with rigid stabilizer at L4-L5 segment (rigid fusion) and dynamic stabilizer at degenerated L3-L4 segment. An interspinous implant, Device for Intervertebral Assisted Motion (DIAM, Medtronic Inc., Minnesota, USA), was used as the dynamic stabilizer. The stress responses of spine segments and implants under a vertical cyclic load were calculated and analyzed. The results showed that compared with rigid fusion alone, the topping-off technique significantly decreased disc stress at transition segment (L3-L4) as expected, and resulted in a slight increase in disc stress at its supra-adjacent segment (L2-L3). It indicated that the topping-off stabilization using DIAM might provide a good tradeoff between protection of transition segment and deterioration of its supra-adjacent segment during WBV. Also, it was found that bony fusion decreased stress in L4 inferior endplate and rigid stabilizer but had nearly no effect on stress in DIAM and L3-L4 disc, which was helpful to determine the biomechanical differences before and after bony fusion.

Biomechanical changes of degenerated adjacent segment and intact lumbar spine after lumbosacral topping-off surgery: a three-dimensional finite element analysis

BackgroundPrevious studies have revealed positive effect of Topping-off technique on upper adjacent segment after fusion surgery, while for the cases with fusion surgery on L5-S1 segment, owning maximal range of motion, and preexisting degenerated upper adjacent disc, it is necessary to clarify the superiority of Topping-ff technique and the effect exerted on the lumbar spine.MethodsA young healthy male volunteer was selected for thin-slice CT scanning. Then the image information was imported into the computer to establish the whole lumbar spine model as the health model. The medium degeneration model of intervertebral disc was established by changing the material properties of L4-S1 disc on the basis of the health model, and the fusion model and Topping-off model were respectively established on the basis of the degenerated model. The variation trend of ROM of L2-L5 and the stress changes of L4-L5 intervertebral disc, nucleus pulposus and facet joints were calculated respectively.ResultsThe L4-L5 ROM of fusion model increased significantly but the ROM of L2-L3 and L3-L4 segments did not change significantly. Compared with the degenerated model, L4-L5 activity of the Topping-off model decreased, and ROM of the L2-L3 and L3-L4 increased to some extent in the flexion and extension positions. The stress on the disc, nucleus pulposus and facet joint of the fusion model L4-L5 increased in four positions of flexion, extension, rotation and bending compared with the degenerated model, while the fiber stress on the Topping-off model decreased significantly in all four positions.ConclusionTopping-off technology can decrease the stress and ROM of the adjacent upper degenerated segment, and increase the ROM of other upper segments, thereby protecting the degenerated upper adjacent segments and compensating the lumbar spine mobility.

Topping-off surgery vs posterior lumbar interbody fusion for degenerative lumbar disease: a finite element analysis

BackgroundAdjacent segment disease (ASD) is a common complication after posterior lumbar interbody fusion (PLIF). Recently, a topping-off surgery (non-fusion with Coflex) has been developed to reduce the risk of ASD, yet whether and how the topping-off surgery can relieve ASD remains unclear. The purpose of this study was to explore the biomechanical effect of PLIF and Coflex on the adjacent segments via finite element (FE) analysis and discuss the efficacy of Coflex in preventing ASD.MethodsA FE model of L3–L5 segments was generated based on the CT of a healthy volunteer via three commercially available software. Coflex and PLIF devices were modeled and implanted together with the segment model in the FE software. In the FE model, a pre-compressive load of 500 N, equal to two-thirds of the human body mass, was applied on the top surface of the L3. In addition, four types of moments (anteflexion, rear protraction, bending, and axial rotation) set as 10 Nm were successively applied to the FE model combined with this pre-compressive load. Then, the range of motion (ROM), the torsional rigidity, and the maximum von Mises equivalent stress on the L3–L4 intervertebral disc and the implant were analyzed.ResultsBoth Coflex and PLIF reduced ROM. However, no significant difference was found in the maximum von Mises equivalent stress of adjacent segment disc between the two devices. Interestingly enough, both systems increased the torsional rigidity at the adjacent lumbar segment, and PLIF had a more significant increase. The Coflex implant had a larger maximum von Mises equivalent stress.ConclusionsBoth Coflex and PLIF reduced ROM at L3–L4, and thus improved the lumbar stability. Under the same load, both devices had almost the same maximum von Mises equivalent stress as the normal model on the adjacent intervertebral disc. But it is worthy to notice the torsional rigidity of PLIF was higher than that of Coflex, indicating that the lumbar treated with PLIF undertook a larger load to reach ROM of Coflex. Therefore, we presumed that ADS was related to a higher torsional rigidity.

Topping-off surgery vs posterior lumbar interbody fusion for degenerative lumbar disease: a comparative study of clinical efficacy and adjacent segment degeneration

BackgroundStudies have shown that adjacent segment degeneration (ASD) is a common complication after posterior lumbar interbody fusion (PLIF), even a second surgery is required for some patients. It remains unclear whether the non-fusion surgery can relieve ASD. Therefore, this study aims to investigate the clinical outcomes of Topping-off surgery (fusion combined with Coflex) and PLIF for degenerative lumbar disease (DLD) and the efficacy on preventing ASD.MethodA retrospective analysis was performed on the clinical data of 99 patients with DLD from January 2011 to December 2014, who were performed by Topping-off surgery (L4–5 PLIF + L3–4 Coflex, n = 45) or PLIF (L3–5 PLIF, n = 54). All patients included in the analysis had a minimum of 3 years of follow-up. Clinical data were used to assess the clinical efficacy, and radiographic parameters were measured for evaluation of the incidence of ASD.ResultsThe mean ages of Topping-off group and PLIF group were 53.5 and 65.7 years old, respectively (P < 0.05). The surgical time, intraoperative blood loss, Oswestry disability index (ODI), and visual analog scale (VAS) were significantly different between the two groups (P < 0.05). Intervertebral mobility (L2-L3) of the Topping-off group was not changed significantly at 3 years after surgery than before (P > 0.05), while that of PLIF group was increased considerably (P < 0.05). As to intergroup comparison, intervertebral mobility (L2-L3) of Topping-off group was superior to those of the PLIF group (P < 0.05). Surprisingly, there was no significant difference in the general adjacent segment mobility (GASM) at L2–4 of the Topping-off group and intervertebral mobility (L2–L3) of PLIF group at 3 years after surgery (P > 0.05). Lumbar MRI at three post-operative years indicated that the modified Pfirrman grading of disc (L2–L3) in the Topping-off group was much better than that of the PLIF group (P < 0.05).ConclusionThis study showed that Topping-off surgery had the benefits of less invasiveness, less bleeding, and comparable clinical efficacy as PLIF for DLD. The segment with Coflex insertion undertook part of the mobility and stress in the proximal lumbar spine, which is conducive to alleviating ASD.

Topping-off surgery versus double-segment fusion for treatment of lumbar degenerative disease with mid-long term follow-up

Objective: To compare the mid-long term clinical effect of Topping-off surgery and lumbar fusion surgery for two-segmental lumbar degenerative disease. Methods: From March 2009 to March 2012, one hundred and twenty-six consecutive patients (Topping-off surgery and two-segment PLIF surgery) were studied in Orthopedics Department, Beijing Chao-Yang Hospital, Capital Medical University.The VAS and ODI were used to assess clinical symptoms.All patients underwent flexion/extension radiographs examinations before surgery, 1, 2 years and last follow-up postoperatively.Lumbar lordosis, sacral slop, data of Coflex segment and adjacent segment (disc height index, range of motion, foraminal height, foraminal width and Pfirrmann classification of intervertebral disc in MRI) were recorded.The paired double-tailed t test was used to analyze the differences in the results from baseline to each postoperative time point.The paired double-tailed t test was used in both groups to analyze the differences in the results from baseline to each postoperative time point.The Chi-square test was used to evaluate the differences between the incidences of adjacent segment degeneration(ASD) in the groups. Logistic regression analysis was used to analyze risk factors for developing radiographic ASD. Results: In topping-off group, 60 patients, average operation time was (134.5±10.2) min. The average blood loss was (301.5±64.6) ml.In fusion group, 68 patients, average age (58.3±4.6) years.The average follow-up time was (47.5±5.1) months.The average operation time was (158.6±19.3) min (P=0.000). The average blood loss was (413.6±131.3) ml (P=0.000). Sex, age, body mass index and intervertebral disc grading were matched between the two groups.Better improvement in VAS back pain score was noted in the topping-off group over the fusion group (P=0.030). Both groups achieved good recovery in ODI and improvement in VAS leg pain and back pain scores at last follow-up postoperatively.In the Topping-off group, FH increased from 10.5 mm at baseline to 11.8 mm at 1 year after surgery (P=0.000) and then decreased mildly in the third postoperative year, while in the fusion group, showed no significant change at all postoperative time points.In the fusion group, the disc height and FW at the same segment were no significant change after first year follow-up, while ROM was significantly decreased after surgery (P=0.000). Foraminal height, foraminal width and intervertebral disc height of adjacent segment of Coflex implant level were found decreased at the end of the postoperative follow-up, while compared with preoperative data no significant difference (P>0.05). At last follow-up, eight patients (13.3%) in the Topping-off group and eighteen patients (26.5%) in the fusion group developed ASD (P=0.033). Conclusions: Topping-off surgery compared with two-segment lumbar fusion surgery can achieve a good result in cases with pre-existing mild or moderate adjacent segment degeneration, restrict the adjacent segment's range of motion and reduce the adjacent segment degeneration. Under strict indications, Topping-off surgery is an acceptable alternative to fusion surgery for the treatment of two-segment lumbar disease.

Radiographic study of Coflex interspinous device for lumbar spinal stenosis

To assess the radiography change of lumbar spinal stenosis (LSS) treated with the implantation of Coflex interspinous device retrospectively. Sixty patients (34 male and 26 female) with LSS who underwent the decompression and Coflex device implanted surgery from January 2010 to December 2013 were followed up. The mean age of the patients was 59.4 years. There were 33 cases underwent Coflex surgery and 27 cases underwent Topping-off surgery. The Coflex segment ranged from L1/2 to L4/5 (L1-2: 1, L2-3: 5, L3-4: 19, L4-5: 35). The foraminal height, foraminal width and intervertebral space height change of the Coflex segment as well as its adjacent segment were recorded pre-/post-operatively and at last follow-up.Meanwhile, the Oswestry Disability Index(ODI) and Visual Analog Scale(VAS) were measured in all patient pre-/post-operatively and at last follow-up. The measurement data was recorded asx±s. And the independent and paired samples t-test was used to conduct the statistical analysis. The foraminal height(FH) increased from (19.82±2.38) mm to (22.28±2.95) mm (P<0.05) post-operatively, and the FH decreased to (19.31±3.32) mm at the last follow up(P>0.05, compared to the post-operation). The average foraminal width(FW) was 11.2 mm, 11.58 mm and 11.12 mm at pre-/post-operation and follow up, which had no significant different change(P>0.05). The post-operative intervertebral space height (ISH) increased from (7.84±1.56) mm to (10.05±2.39) mm(P<0.05), and the ISH decreased to (7.91±1.77) mm at the last follow up(P>0.05, compared to the post-operation). The amount of the decreased FH and ISH had no significant difference when comparing the Coflex segment with its adjacent (Coflex±1) segments (P>0.05). The lumbar lordosis(LL) was 43.13°±15.93°, 38.41°±10.82° and 43.10°±13.21° at pre-/post-operation and follow up, there was no significant difference between pre- and post-operation(P>0.05). All patients showed statistically significant improvement(P<0.05) in the clinical outcome assessed in the VAS and ODI at the time of follow up compared to the pre-operation. The ODI score decreased from 65.12±13.56 to 9.89±1.77; the VAS score decreased from 8.02±1.81 to 1.66±0.51. Coflex device could temporarily improve the FH and ISH after operation. However, it could not maintain the improvement as the follow-up time extended. The surgical decompression is the responsible factor for the good clinical outcome but not the improvement of FH.

Interspinous dynamic stabilization adjacent to fusion versus double-segment fusion for treatment of lumbar degenerative disease with a minimum follow-up of three years.

The aim of this study was to assess the outcome of symptomatic lumbar degenerative disease treated with topping-off technique (Coflex(™) combined with fusion) and compare two-segment fusion at mid-long term follow-up; and find out whether the topping-off technique can reduce the rate of adjacent segment degeneration (ASD) after fusion. One hundred and fifty-four consecutive patients who received topping-off surgery (76 patients) and two-segment fusion surgery (88 patients) from March 2009 to March 2012 were studied. All patients included in the analysis had a minimum of threeyears of follow-up. Radiographic and clinical outcomes between the two groups were compared. A logistic regression analysis was used to analyze risk factors for developing radiographic ASD. Significant differences in clinical outcomes were observed between these two groups at three post-operative years (all, p < 0.05). Compared with the fusion group, the topping-off group showed preserved mobility at the Coflex(™) level (p = 0.000), which is associated with less blood loss (p = 0.000), shorter duration of surgery (p = 0.000) and lower incidence of ASD (Chi-square test, rate topping-off vs fusion = 13.2 vs 26.1%, p = 0.039). There were no differences in complications between the two groups. Mid-long term follow-up efficacy and safety between topping-off and fusion were similar, while topping-off reduced the rate of ASD. Under strict indications, topping-off surgery is an acceptable alternative to fusion surgery for the treatment of two-segment lumbar disease.

Efficacy of Topping-Off Surgery in Preventing Adjacent Segment Degenerative Stenosis of the Lumbar Spine: A Radiographical and Clinical Study

Introduction Adjacent segment degeneration or disease (ASD or ASDs) has been one of the most concerned issues after fusion of the lumbar spine. To investigate the radiographical and clinical outcome of adjacent segment degeneration after topping-off (posterior lumbar interbody fusion + above segment interspinous implant) procedure, a retrospective study was conducted. Materials and Methods All lumbar spinal stenosis cases from the department of orthopedics of Beijing Chaoyang hospital that received PLIF + above segment Coflex between August 2008 and October 2012 were analyzed retrospectively. Analysis the gender, age, body mass index of all the patients was done. The X-ray films before and after surgery were measured and got some data (total lordosis, the height of disc, range of motion, lordosis, and olithesis). One-year follow-up were examined by MRI, observed the degeneration of intervertebral disc. All data used SPSS 12.0 for analysis. Results There were 32 patients in topping-off (males 21 and females 11), including (L4/5 PLIF + L5–S1 Coflex) 12 patients in group 1 and (L3/4 PLIF + L4/5 Coflex) 20 patients in group 2. Age averaged 61.5 years (range, 30–79 years) and follow-up averaged 24.6 months (range, 14–63 months). The average surgery time was 110 ± 21 minutes. The average blood loss was 401 ± 110 mL. Postoperation the ODI, JOA, and VAS score improved. There was no significant difference in the height of disc of the Coflex segment and above segment between before and after surgery. Segmental lordosis of Coflex and total lordosis were all increased significantly ( t = −1.9 and −2.0, p &lt; 0.05). There was no significant difference in the number of the disc change of Modic grade of end plate ( p &gt; 0.05). Conclusion Topping-off surgery is fit for the patients who have serious stenosis of lumbar spinal cord with mild and moderate stenosis of adjacent segment, which can restrict the adjacent segment's range of motion and prevent excessive olisthesis of adjacent segment in both extension and flexion, also can sustain the height of Coflex segment. It shows a good result after short-term follow-up. Topping-off surgery plays an active role in preventing the adjacent segmental degeneration.

Efficacy of Topping-Off Surgery in Preventing Adjacent Segment Degeneration of the Lumbar Spine: A Radiographic Study

Introduction The aim of the study is to investigate the image change of adjacent segment degeneration after topping-off (posterior lumbar interbody fusion + above segment interspinous implant). Materials and Methods All lumbar spinal stenosis cases from the department of orthopedics of Beijing Chaoyang Hospital that received PLIF + above segment Coflex between August 2008 and October 2012 were analyzed retrospectively. Analysis the gender, age, body mass index of all the patients was done. The X-ray films before and after surgery were measured and got some data (total lordosis, the height of disc, range of motion, lordosis and olithesis). Modic changes (modic grades) of endplate and disc changes (modified Pfirrmann grades) were recorded. All data used SPSS 12.0 to analysis. Results There were 32 patients in Topping-off (male 21, female 11), including group 1 (L4/5 PLIF+L5S1 Coflex) 12 patients and group 2 (L3/4 PLIF+ L4/5 Coflex) 20 patients. Age averaged 61.5 years old (range, 30-79 years), follow-up averaged 24.6 months (range, 63-11 years). The average surgery time was 110 ± 21 minutes. The average blood loss was 401 ± 110 mL. Postoperatively, the ODI, JOA, and VAS score improved. There was no significant difference in the height of disc of the Coflex segment and above segment between before and after surgery. Segmental lordosis of Coflex and total lordosis were all increased significantly ( t = −1.9 and −2.0, p &lt; 0.05). There was no significant difference in the number of the disc change by modic grade of endplate ( p &gt; 0.05). Preoperative MRI: the disc change of Coflex segment (modified Pfirrmann grades)—9 patients grade 4, 15 patients grade 5, 8 patients grade 6 and modic changes of endplate 6 patients grade 2, 4 patients grade 1, all the others grade 0. The adjacent segment (modified Pfirrmann grades) 27 patients grade 1, 5 patients grade 2, and all the patients of the modic changes of endplate grade 0; over 24 months postoperation 24 patients made MRI, there was no significant difference in the number of the disc changes and modic changes of endplate ( p &gt; 0.05). Conclusion Topping-off surgery is fit for the patients who have serious stenosis of lumbar spinal cord with mild and moderate stenosis of adjacent segment, which can restrict the adjacent segment's range of motion in both extension and flexion, also can sustain the height of Coflex segment. After follow-up over 24 months, MRI indicates that topping-off surgery can prevent the adjacent segmental degeneration. Disclosure of Interest None declared

Adjacent Intervertebral Disc Changes in Patients with Isobar Semirigid Dynamic Stabilization System

Introduction The reported incidence of adjacent segment degeneration (ASD) after lumbar fusion ranges from 8 to &gt; 100%, average 27%. Another literature review reported that 5.2 to 18.5% of patients required surgery for adjacent segment disease after lumbar fusion surgery. Posterior dynamic stabilization systems may prevent the development and progression of ASD after surgery. Hybrid dynamic stabilization with posterior spinal fusion, or “Topping-off surgery,” is applied in patients with preoperative adjacent segment degeneration. The objective of this approach is to protect the degenerative adjacent segment from progressing. Efficacy of this procedure is debated. The objective of this study was to evaluate intervertebral disk changes of the dynamically stabilized spine segment in patients receiving single-level intervertebral fusion and adjacent segment dynamic stabilization using the Isobar (Alphatec Spine, Inc.) semirigid dynamic stabilization system. Materials and Methods Twenty-seven patients with confirmed degenerative disk disease were enrolled in a retrospective study. Patients received single level intervertebral fusion and dynamic stabilization of the adjacent level using the Isobar semi-rigid dynamic stabilization system. Patient outcomes were evaluated by visual analogue scale for pain (VAS) and Chinese version of Oswestry Disability Index (ODI). Intervertebral space ratio (IVS) and range of motion (ROM) were measured on plain radiographs. MRI relative gray-scale values of the central bright area of discs were analyzed by Image J software. Results Of the 27 patients, 16 were male and 11 were female. Ages ranged from 31 to 65 years (average 47 years). Average duration of surgery was 213 (SD = 52) minutes and average blood loss was 225 mL (SD = 105). The average follow-up time was 27 months, ranging from 24 to 40 months. There was no significant change in relative gray-scale value of adjacent disc between preoperative and two year follow-up (23.98 ± 8.86 and 22.22 ± 6.25, respectively, p = 0.46). Relative gray-scale values of first cephalic adjacent disc were reduced at 2 years follow-up compared with baseline (28.63 ± 8.35 and 32.54 ± 10.75, respectively, p = 0.06). Significant difference was found in relative gray-scale value of second cephalic adjacent disc between baseline and 2-year follow-up (35.51 ± 8.15 and 29.29 ± 7.56, respectively, p &lt; 0.01). The inter-vertebral space (IVS) of index level was maintained after the surgery (Table 1). There was no statistical difference between the IVS before the surgery and final follow-up ( p = 0.33). The range of motion (ROM) of the adjacent level was reduced from 6.91 ± 3.14 preoperatively to 2.46 ± 1.03 degrees at the final follow-up ( p &lt; 0.05). There were no significant differences in the index level ROM among any of the follow-up times. VAS and ODI scores significantly improved preoperatively to final follow-up (VAS: 6.12 ± 0.80 and 1.65 ± 0.69, respectively, p = &lt; 0.01; ODI: 54.91 ± 10.96 and 14.61 ± 3.88, respectively, p = &lt;0.01). One patient received a debridement due to wound infection after operation, but the fixation system and interbody cage were not removed. This patient recovered well after the debridement. At the 2-year follow-up, one patient had two screw fractures at S1 level and another patient had two screws loosen. Conclusion Dynamic stabilization of the level adjacent to the fused level using the Isobar TTL Semi-rigid Spinal System seems to prevent progression of degenerative changes in the stabilized spine segment and is associated with favorable patient outcomes. Disclosure of Interest Q. Zhou: Conflict with Third Military Medical University, AO International R. Shi: None declared B. Kopjar: Conflict with AO Foundation, Smith &amp; Nephew, Cerapedics H. Wang: None declared D. Chen: None declared H. Li: None declared N. Di: None declared F. Luo: None declared F. Dai: None declared J. Xu: None declared