Isobar TTL Research Articles

Correlation of the single-segment dynamic stabilization with different segmental mobility and zygapophysial (facet) joint degeneration: a retrospective study in northern China

ObjectiveTo compare the clinical and radiographic outcomes of single-segment posterior decompression combined with two different non-fusion dynamic stabilization systems, Isobar EVO and Isobar TTL, in the context of facet joint degeneration and segmental mobility.MethodA retrospective study was conducted on 47 patients who underwent single-segment surgery at the L4/5 level using either the Isobar EVO (n = 23) or Isobar TTL (n = 24) systems. We assessed facet joint degeneration on both sides of the fixed (L3/4, L4/5) and superior adjacent (L2/3) segments using the Fujiwara MRI grading system. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain at baseline, 12 months, and 24 months postoperatively.ResultBoth groups exhibited significant facet joint degeneration at the fixed segments (L3/4 and L4/5) at 24 months. The TTL group also showed significant degeneration at the superior adjacent segment (L2/3), whereas the EVO group did not. Restoration of lumbar lordosis was significantly better in the EVO group. Pain and disability scores improved more in the EVO group than in the TTL group at both 12 and 24 months postoperatively.ConclusionThe Isobar EVO system, with its enhanced mobility, may delay facet joint degeneration in the superior adjacent segment compared to the Isobar TTL system. However, both systems result in degeneration at the fixed segment, indicating a need for further improvements to mimic the natural biomechanics of the spine more closely.

Long-term Outcome of Isobar TTL System for the Treatment of Lumbar Degenerative Disc Diseases.

The Isobar TTL dynamic fixation system has demonstrated favorable outcomes in the short-term treatment of lumbar degenerative disc diseases (LDDs). However, there is a paucity of extensive research on the long-term effects of this system on LDDs. This study aimed to evaluate the long-term clinical and radiological outcomes of patients with LDDs who underwent treatment utilizing the Isobar TTL dynamic fixation system. The study analyzed the outcomes of 40 patients with LDDs who underwent posterior lumbar decompression and received single-segment Isobar TTL dynamic internal fixation at our hospital between June 2010 and December 2016. The evaluation of clinical therapeutic effect involved assessing postoperative pain levels using the visual analogue scale (VAS) and Oswestry disability index (ODI), both before surgery, 3 months after, and the final follow-up. To determine the preservation of functional motion in dynamically stable segments, we measured the range of motion (ROM) and disc height of stabilized and adjacent segments preoperatively and during the final follow-up. Additionally, we investigated the occurrence of adjacent segment degeneration (ASD). Forty patients were evaluated, with an average age of 44.65 years and an average follow-up period of 79.37 months. Fourteen patients belonged to the spondylolisthesis group, while the remaining 26 were categorized under the stenosis or herniated disc group. The preoperative ROM of the stabilized segment exhibited a significant reduction from 8.15° ± 2.77° to 5.00° ± 1.82° at the final follow-up (p < 0.001). In contrast, there was a slight elevation in the ROM of the adjacent segment during the final follow-up, increasing from 7.68° ± 2.25° before surgery to 9.36° ± 1.98° (p < 0.001). The intervertebral space height (IH) in the stabilized segment exhibited a significant increase from 10.56 ± 1.99 mm before surgery to 11.39 ± 1.90 mm at the one-week postoperative follow-up (p < 0.001). Conversely, there was a notable decrease in the IH of the adjacent segment from 11.09 ± 1.82 mm preoperatively to 10.86 ± 1.79 mm at the one-week follow-up after surgery (p < 0.001). The incidence of ASD was 15% (6/40) after an average follow-up period of 79.37 months, with a rate of 15.38% (4/26) in the stenosis or herniated disc group and 14.29% (2/14) in the spondylolisthesis group; however, no statistically significant difference was observed in the occurrence of ASD among these groups (p > 0.05). The Isobar TTL dynamic fixation system is an effective treatment for LDDs, improving pain relief, quality of life (QoL) and maintaining stabilized segmental motion. It has demonstrated excellent long-term clinical and radiographic results.

Clinical Outcomes of Isobar TTL System with Isthmic Bone Grafting and Pedicle Screw-Vertebral Plate Hook with Direct Repair of Defect for Lumbar Spondylolysis: A Matched-Pair Case Control Study.

Although direct isthmic repair, such as PSVPH, did not affect the mobility of the fixed segment and adjacent segment, it has a relatively low rate of isthmic fusion compared with conventional fusion. The Isobar TTL dynamic internal fixation system has been widely used in clinical practice and has achieved satisfactory clinical results. However, the use of the Isobar TTL system in combination with direct isthmic repair for lumbar spondylolysis has rarely been reported. The aim of this study was to compare the clinical and radiologic outcomes between patients who underwent Isobar TTL system and PSVPH with direct repair of defect for lumbar spondylolysis. Stepwise propensity score matching (PSM) for age and sex were performed to keep comparable clinical data between groups in this retrospective and matched-pair case control study. A total of 50 patients diagnosed with lumbar spondylolysis underwent surgical implantation of the Isobar TTL group (n = 25) or PSVPH group (n = 25) from June 2009 to June 2016. Clinical outcomes were assessed using the Oswestry disability index (ODI), and visual analog score (VAS). Radiographic evaluations included range of motion (ROM) and the disc heights of stabilized segment and adjacent segment, adjacent segment degeneration (ASD) and bony fusion. Three-dimensional reconstruction of lumbar CT scan was obtained to evaluate bone fusion of the isthmic at final follow-up. The independent Student's t test and chi-square test were applied to compare the differences between groups. A total of 25 patients from TTL group were matched to 25 patients in PSVPH group for age, sex, body mass index (BMI), defect side, spondylolisthesis meyerding, and follow-up duration. The intervertebral space height (IH) of stabilized segment at postoperative 1 week and final follow-up in the TTL group was higher than those in the PSVPH group, respectively (P = 0.030; P = 0.013). The ROM of stabilized segment at final follow-up in the TTL group was significantly lower than that in the PSVPH group (P < 0.001). The bony fusion rate at the final follow-up was 88.0% (22/25 cages) in the TTL group and 80.0% (20/25 cages) in the PSVPH group. The ODI score at final follow-up in the TTL group was significantly lower than that in the PSVPH group (P = 0.007). Overall, our data suggest that the Isobar TTL system outcomes are comparable to those in the PSVPH, with a similar high bony fusion rate as PSVPH, especially its wider indications as a new surgery.

Isobar hybrid dynamic stabilization with posterolateral fusion in mild and moderate lumbar degenerative disease

ObjectiveThe aim of this study was to investigate the feasibility of using the Isobar TTL system and posterolateral fusion in a two-segment hybrid fixation approach, combined with spinal decompression, for treating mild and moderate lumbar degenerative disease. Specifically, we sought to evaluate the effectiveness of this approach for managing two-segment mild and moderate lumbar degenerative disease, and to determine whether it could provide a safe and reliable alternative to traditional surgical methods.MethodsThis retrospective study included 45 consecutive patients with two-level lumbar disc herniation or spinal stenosis, 24 of whom underwent the TTL system and posterolateral fusion combined (TTL group), and 21 of whom underwent posterolateral fusion alone (Rigid group). The surgical segment, admission diagnosis, operation time, and intraoperative bleeding were recorded separately for the two groups of patients. Imaging studies included pre- and postoperative radiography, magnetic resonance imaging, and computed tomography. The clinical outcomes were measured by Oswestry Disability Index (ODI) scores, and a visual analogue scale (VAS) for back and leg pain.ResultsAll patients completed the surgery successfully with a mean follow-up of 56.09 months. The operative time and intraoperative bleeding were lower in the TTL group than in the Rigid group (p < 0.05). All patients showed significant improvements in clinical outcomes, including VAS for back and leg pain, and ODI scores (p < 0.05). ODI scores, the TTL group was better than the Rigid group at 1 year after surgery and at the final follow-up (p < 0.05). Postoperative surgical segment range of motion (ROM) decreased in both groups (p < 0.05). The postoperative ROM of the upper adjacent segment increased in both groups and was significantly higher in both groups at the last follow-up compared with the preoperative period (p < 0.05), and the superior adjacent segment rom of the TTL group was lower than the Rigid group (p < 0.05). The modified Pfrrmann classification of the superior adjacent segment was significantly increased in both groups at the last follow-up (p < 0.05). And in the TTL group, ROM, DH, and modified Pfrrmann grading of dynamic segment outperformed fusion segments. According to the UCLA classification, the incidence of adjacent segment degeneration (ASD) was 4.2% in the TTL group and 23.8% in the Rigid group, and the incidence of ASD was lower in the TTL group than in the Rigid group (P < 0.05).ConclusionThe Isobar TTL System was utilized in two-level lumbar hybrid surgery, resulting in no evident indications of lumbar instability being detected on X-rays captured at a minimum of 4 years after the operation, while retaining partial range of motion of the surgical segment. The general clinical efficacy is equivalent to titanium rod fusion surgery, presenting an alternative treatment for individuals with mild and moderate lumbar degenerative disease.

Correlation between surgical segment mobility and paravertebral muscle fatty infiltration of upper adjacent segment in single-segment LDD patients: retrospective study at a minimum 2 years’ follow-up

ObjectiveThe purpose of this study was to investigate the relationship between surgical segment mobility and fatty infiltration of the adjacent segment paravertebral muscles in patients with single-segment lumbar degenerative disease (LDD) who underwent decompression with fusion or dynamic stabilization.MethodsRetrospective analysis of patients who underwent lumbar decompression combined with titanium rod fixation intertransverse fusion (PITF group), Isobar TTL dynamic stabilization (TTL group) or Isobar EVO dynamic stabilization (EVO group) for single-segment lumbar degenerative disease, from March 2012 to July 2018. The preoperative and final follow-up clinical indexes C-LDSI and the measured imaging indexes (range of motion of the surgical segment and the upper adjacent segment, and Goutallier grade of the upper adjacent segment) were counted, and the differences between the preoperative and final follow-up indexes were compared.ResultsAccording to the inclusion and exclusion criteria, 68 patients were included in this study, 21 in the PITF group, 24 in the TTL group, and 23 in the EVO group. At the final follow-up, the C-LSDI score had significantly higher in the PITF group than the TTL and EVO groups, and the C-LSDI score was a very strongly negatively correlated with ROM of surgical segment (r=-0.7968, p < 0.001). There was a strong negative correlation between surgical segment and upper adjacent segment mobility (r = -0.6959, p < 0.001). And there was a very strong negative correlation between ROM of surgical segment and upper adjacent segment paravertebral muscle Goutallier classification (r = -0.8092, p < 0.001), whereas the ROM of the upper adjacent segment was strong positive correlated with the Goutallier classification (r = 0.6703, P < 0.001).ConclusionCompared with decompression combined with rigid fusion, decompression combined with dynamic fixation for single-segment lumbar degenerative disease can significantly reduce postoperative low back stiffness. And a certain range of increased mobility of the dynamic stabilization device can effectively reduce the compensatory mobility of the upper adjacent segment and slow down the fatty infiltration of the paravertebral muscle in the adjacent segment.

Comparison between single-segment Isobar EVO dynamic stabilization and Isobar TTL dynamic stabilization in the treatment of lumbar degenerative diseases: a single center retrospective study over 4 years

ObjectivePosterior instrumented fusion is the most widely accepted surgical treatment for spinal stenosis and disc herniation. However, fusion can affect daily activities due to lumbar stiffness. In recent years, dynamic stabilization has been introduced to overcome the drawbacks of fusion, however, it is inconclusive whether dynamic stabilization requires the maintenance of a level of activity that is closer to the physiological state of activity for better clinical efficacy. The purpose of this study was to compare the effectiveness of dynamic stabilization with different levels of activity (Isobar EVO and TTL) in the treatment of spinal stenosis and disc herniation.MethodsThis study retrospectively reviewed 80 consecutive patients with lumbar degenerative diseases who were undergoing surgical treatment between March 2014 and July 2018. 41 patients (EVO group) and 39 patients (TTL group) underwent fenestrated decompression with Isobar EVO stabilization and Isobar TTL stabilization, respectively. Clinical outcomes, radiographic data, and postoperative complications were compared between the two groups.ResultsAt an average follow-up of 52.23 ± 2.97 months, there were no significant differences in the oswestry disability index (ODI) (P > 0.05). The visual analog scale for back pain (VASback) and visual analog scale for the leg pain (VASleg) of the EVO group were lower compared with the TTL group (P < 0.05). The range of motion (ROM) of operated segments were significantly higher in the EVO group as compared to the TTL group (P < 0.05). The intervertebral space height (ISH) of upper adjacent segments were significantly higher in the EVO group as compared to the TTL group (P < 0.05). The overall complications were less in the EVO group, but the difference was not statistically significant (P > 0.05).ConclusionBoth Isobar EVO dynamic stabilization and TTL dynamic stabilization can improve clinical outcomes of patients with spinal stenosis and disc herniation. Isobar EVO has advantages over Isobar TTL in terms of improving low back and leg pain, maintaining mobility of the operated segment, and preventing further degeneration of the upper adjacent segment.

Analysis of clinical effect and radiographic outcomes of Isobar TTL system for two-segment lumbar degenerative disease: a retrospective study

BackgroundNonfusion fixation is an effective way to treat lumbar degeneration. In the present study, we analyzed the clinical effects and radiographic outcomes of the Isobar TTL system used to treat two-segment lumbar degenerative disease.MethodForty-one patients diagnosed with two-segment lumbar degenerative disease underwent surgical implantation of the Isobar TTL dynamic stabilization system (n = 20) or a rigid system (n = 21) from January 2013 to June 2017. The mean follow-up time was 23.6 (range 15–37) months. Clinical results were evaluated with the Oswestry Disability Index (ODI), modified Macnab criteria, and the visual analog score (VAS). Radiographic evaluations included the height of the intervertebral space and the range of motion (ROM) of the treated and adjacent segments. The intervertebral disc signal was classified using the modified Pfirrmann grading system and the University of California at Los Angeles (UCLA) system.ResultsThe clinical results, including the ODI and VAS, showed that there was significant improvement in the two groups after implantation and that the difference between the two groups was not significant. In addition, the clinical efficacy indicated by the modified Macnab criteria for the two groups was similar. Radiological outcomes included the height of the intervertebral space, lumbar mobility, and intervertebral disc signal. The height of the intervertebral space of the upper adjacent segment L2/3 in the rigid group was significantly lower than that in the Isobar TTL group at the last follow-up. Furthermore, the number of ROMs of the fixed-segment L3/4 in the Isobar TTL group was significantly less than that before implantation, suggesting that the fixed-segment ROMs in the Isobar TTL group were limited. In addition, the ROM of the upper adjacent segment L2/3 in the last follow-up of the rigid group increased significantly, while that of the Isobar TTL group did not change after implantation. Finally, the incidence of adjacent-segment degeneration (ASD) was significantly greater in the rigid group than in the Isobar TTL group according to the UCLA system.ConclusionThe Isobar TTL system can be clinically effective for treating two-segment lumbar degenerative disease. Compared with rigid fixation, the Isobar TTL system yielded better radiographic outcomes and maintained the mobility of the treated segments with less impact on the proximal adjacent segment.

Therapeutic effect of Isobar TTL fixation system on lumbar degenerative disease and discussion on postoperative fusion rate

To evaluate the therapeutic effect of Isobar TTL dynamic internal fixation system on lumbar degenerative disease and to explore the postoperative fusion rate. The clinical data of 80 patients with lumbar degenerative disease underwent Isobar TTL dynamic internal fixation system from April 2013 to January 2016 were retrospectively analyzed. There were 39 males and 41 females, aged from 28 to 69 years old with an average of 46.4 years, 42 cases of single segment and 38 cases of double segments. Visual analogue scale (VAS), Oswestry Disability Index (ODI) and the modified Macnab criteria were used to evaluate the clinical effects. The intervertebral range of motion (ROM) and intervertebral height ratio (ISR) were measured by X-ray films. According to the standard established by SUK to evaluate the intervertebral fusion of dynamic fixed segment. All the patients were followed up for 17 to 45 months with an average of 31.9 months, a total of 30 cases completed imaging review. VAS and ODI scores of 80 cases respectively were 9.15±1.55, 38.65±9.60 before operation, 0.55±1.18, 1.06±2.17 at 2 weeks after operation, 0.24±0.70, 0.16±0.48 at the final follow-up. The VAS and ODI scores at 2 weeks and the final follow-up were significantly lower than those preoperative(P<0.05). At the final follow-up, according to modified Macnab criteria to evaluate the clinical effect, 65 cases obtained excellent results, 14 good, 1 fair. In the 30 cases completed imaging review, the ROM of the dynamic fixed segment was decreased from (6.87±2.18)° preoperatively to (3.52±2.80)°, (3.14±2.60)° at 2 weeks after operation and at the final follow-up(P<0.05). The ROM of the adjacent segment was increased from (4.36±1.28)° preoperatively to (4.80±1.99)°, (6.54±4.83)° at 2 weeks after operation and at the final follow-up(P<0.05). The ISR of dynamic fixed segment and adjacent segment were increased from (36.73±6.36)%, (40.74±7.29)% preoperatively to (38.37±6.35)%, (41.59±7.77)% at 2 weeks postoperatively(P<0.05), and at the final follow-up were decreased to (36.58±9.53)%, (38.25±8.08)%, there was no significant difference between preoperative and the final follow-up(P>0.05). Among them, 20 cases got possible fusion and 10 cases got non-fusion, with the possible fusion rate of 66.7%. Isobar TTL dynamic internal fixation system has a good clinical effect in the treatment of lumbar degenerative disease. Although the ROM of adjacent segments is increased, it can effectively prevent the degeneration of the adjacent segments in the short term. And the dynamic fixation segment tends to fusion.

Clinical outcome of ISOBAR TTL dynamic stabilization with pars bone grafting for treatment of lumbar spondylolysis

To evaluate the effectiveness of ISOBAR TTL dynamic stabilization with pars bone grafting for the treatment of lumbar spondylolysis. A retrospective analysis was made the clinical data of 26 patients with lumbar spondylolysis who received ISOBAR TTL dynamic stabilization with pars bone grafting between September 2009 and March 2014. There were 14 males and 12 females, with a mean age of 31 years (range, 19-47 years). The disease duration ranged from 9 to 60 months (mean, 16 months). Preoperative lumbar anteroposterior and lateral X-ray films, CT three-dimensional reconstruction, and MRI scans were performed to identify the location of pars defect. The involved levels were L 4 in 9 cases and L 5 in 17 cases. There were 10 cases of pure spondylolysis and 16 cases of spondylolysis accompanied with I degree slipping. The clinical outcome was assessed by visual analogue scale (VAS) and Oswestry disability index (ODI) scores at preoperation and 1 week, 3 months, 6 months after operation, and at last follow-up. The lumbar CT three-dimensional reconstruction was obtained at 6 months after operation to evaluate bone fusion of the pars. The adjacent segment degeneration was assessed by the University of California at Los Angeles (UCLA) grading scale at preoperation and last follow-up. All incisions healed by first intention; no infection, cerebrospinal fluid leakage, or pain at iliac crest donor site occurred. Twenty-six patients were followed up 2-5 years (mean, 36.5 months). No secondary spondylolisthesis, internal fixation loosening and breakage were found during follow-up. The postoperative VAS and ODI scores showed significant differences ( P<0.05) when compared with preoperative scores, and the scores at 3 months, 6 months, and last follow-up were significantly better than that at 1 week ( P<0.05), but no significant difference was shown between the other time points after operation ( P>0.05). The CT three-dimensional reconstruction indicated satisfactory union at the pars in 23 cases (88.5%) at 6 months after operation. Of the 3 nonunion patients, good union was obtained in 1 patient at 1 year after operation; nonunion was observed in 2 patients at last follow-up, but low back pain was obviously alleviated. According to the UCLA grading scale, 20 cases were rated as grade I and 6 cases as grade II at last follow-up, which was the same as preoperative grade and indicated no adjacent segment degeneration. It is safe and effective to use the ISOBAR TTL dynamic stabilization with pars bone grafting technique to treat lumbar spondylolysis with or without degree I slipping. The fusion rate is satisfactory, and adjacent segment degeneration can be slowed down after lumbar fusion surgery.

Biomechanics of Posterior Dynamic Fusion Systems in the Lumbar Spine

A comparative biomechanical human cadaveric spine study of a dynamic fusion rod and a traditional titanium rod. The purpose of this study was to measure and compare the biomechanical metrics associated with a dynamic fusion device, Isobar TTL Evolution, and a rigid rod. Dynamic fusion rods may enhance arthrodesis compared with a rigid rod. Wolff's law implies that bone remodeling and growth may be enhanced through anterior column loading (AL). This is important for dynamic fusion rods because their purpose is to increase AL. Six fresh-frozen lumbar cadaveric specimens were used. Each untreated specimen (Intact) underwent biomechanical testing. Next, each specimen had a unilateral transforaminal lumbar interbody fusion performed at L3-L4 using a cage with an integrated load cell. Pedicle screws were also placed at this time. Subsequently, the Isobar was implanted and tested, and finally, a rigid rod replaced the Isobar in the same pedicle screw arrangement. In terms of range of motion, the Isobar performed comparably to the rigid rod and there was no statistical difference found between Isobar and rigid rod. There was a significant difference between the intact and rigid rod and also between intact and Isobar conditions in flexion extension. For interpedicular displacement, there was a significant increase in flexion extension (P=0.017) for the Isobar compared with the rigid rod. Isobar showed increased AL under axial compression compared with the rigid rod (P=0.024). Isobar provided comparable stabilization to a rigid rod when using range of motion as the metric, however, AL was increased because of the greater interpedicular displacement of dynamic rod compared with a rigid rod. By increasing interpedicular displacement and AL, it potentially brings clinical benefit to procedures relying on arthrodesis.

Short-Term Therapeutic Efficacy of the Isobar TTL Dynamic Internal Fixation System for the Treatment of Lumbar Degenerative Disc Diseases

Background: At present, posterior interbody fusion surgery with pedicle internal fixation is the gold standard for the treatment of lumbar degenerative disc diseases. However, an increasing number of studies have shown that because fused lumbar vertebrae lose their physiological activity, the compensatory range of motion (ROM) of the adjacent levels increases. To address this issue, dynamic internal fixation systems have been developed. Objective: Our goal was to investigate the short-term therapeutic efficacy of the Isobar TTL dynamic internal fixation system for the treatment of lumbar degenerative disc diseases and its effect on the ROM of the surgical segments. Study Design: Retrospective Evaluation. Setting: Tertiary hospital setting in China. Methods: Twenty-four lumbar degenerative disc disease patients who underwent posterior lumbar decompression and single-segment Isobar TTL dynamic internal fixation at our hospital between January 2013 and July 2014 were retrospectively analyzed. The preoperative and one month, 3 month, and 12 month postoperative visual analog scale (VAS) pain scores, Japanese Orthopedic Association (JOA) scores, and Oswestry Disability Index (ODI) scores were observed and recorded to assess the clinical therapeutic effect; the lumbar ROM was measured preoperatively and at the last follow-up to evaluate the preservation of functional movement in the dynamically stabilized segment. Results: All patients underwent the operation successfully without complications during hospitalization and were followed for 12 to 27 months, with an average of 18 months. The patients’ preoperative and one month, 3 month, and 12 month postoperative VAS scores were 6.42 ± 0.72, 1.71 ± 0.86, 1.38 ± 0.65, and 1.37 ± 0.58, respectively, and their JOA scores were 9.54 ± 1.89, 21.21 ± 1.98, 22.50 ± 1.47, and 23.46 ± 1.32, respectively. The preoperative ODI score was 42.04 ± 2.63; the one month, 3 month, and 12 month postoperative ODI scores were 22.79 ± 1.61, 18.63 ± 1.61, and 15.08 ± 1.21, respectively. These results suggest that the VAS score at each postoperative time point was significantly lower than the preoperative score and that function was significantly improved postoperatively compared with preoperative function; all of the differences had statistical significance (P &lt; 0.05). The patients’ preoperative lumbar ROM and the ROM at 12 months post operation were 3.46 ± 1.02 and 2.25 ± 0.79, respectively; the difference was not statistically significant (P = 0.11). Limitations: The follow-up time is not long enough. Conclusions: The treatment of lumbar degenerative disc diseases with the Isobar TTL dynamic internal fixation system can effectively relieve pain, improve quality of life, and preserve the lumbar ROM of the stabilized segment with a satisfactory clinical therapeutic effect. Key words: Lumbar degenerative disc diseases, dynamic internal fixation system, Isobar TTL, range of motion

Influence of isobar ttl dynamic internal fixation system on adjacent segment degeneration by mri measurement of lumbar nucleus pulposus volume

?To investigate the influence of ISOBAR TTL dynamic internal fixation system on degeneration of adjacent intervertebral disc by MRI measurement of lumbar nucleus pulposus volume in treating lumbar degenerative disease after operation. ?Between March 2010 and October 2011, 34 patients with lumbar intervertebral disc herniation (23 cases of paracentral type and 11 cases of lateral type) underwent operation with ISOBAR TTL dynamic internal fixation system for fixation of single segment, and the clinical data were analyzed retrospectively. There were 20 males and 14 females, aged 39-62 years (mean, 47.5 years). The disease duration was 6-18 months (mean, 14 months). Involved segments included L4, 5 in 21 cases and L5, S1 in 13 cases. The X-ray films and MRI images were taken at 6, 12, 18, 24, 36, and 48 months after surgery. Based on X-ray films, the height of intervertebral space was measured using angle bisectrix method. The nucleus pulposus volume was measured based on the MRI scan. The postoperative change of nucleus pulposus volume and intervertebral disc height were used to evaluate the influence of ISOBAR TTL system on degeneration of adjacent intervertebral disc nucleus pulposus. ?Thirty patients were followed up 48 months. The height of intervertebral space showed no significant difference between at pre-and post-operation (P>0.05). The nucleus pulposus volume increased after operation, showing no significant difference at 6, 12, and 18 months when compared with preoperative value (P>0.05), but significant difference was found at 24, 36, and 48 months when compared with preoperative value (P<0.05). The height of nucleus pulposus increased after operation but the width was decreased; the values showed no significant difference at 6, 12, and 18 months when compared with preoperative ones, but showed significant difference at 24, 36, and 48 months when compared with preoperative ones (P<0.05). The diameter of nucleus pulposus at 18, 24, 36, and 48 months after operation was significantly langer than that at preoperation (P<0.05). ?ISOBAR TTL dynamic internal fixation system can prevent or delay the degeneration of intervertebral discs.

Nursing Care of Lumbar Spine Fusion Surgery Using a Semi-Rigid Device (ISOBAR)

Aging frequently induces degenerative changes in the spine. Patients who suffer from lumbar degenerative disease tend to have lower back pain, neurological claudication, and neuropathy. Furthermore, incontinence may be an increasing issue as symptoms become severe. Lumbar spine fusion surgery is necessary if clinical symptoms continue to worsen or if the patient fails to respond to medication, physical therapy, or alternative treatments. However, this surgical procedure frequently induces adjacent segment disease (ASD), which is evidenced by the appearance of pathological changes in the upper and lower sections of the spinal surgical sites. In 1997, ISOBAR TTL dynamic rod stabilization was developed for application in spinal fusion surgery to prevent ASD-related complications. The device has proven effective in reducing pain in the lower back and legs, decreasing functional disability, improving quality of life, and retarding disc degeneration. However, the effectiveness of this intervention in decreasing the incidence of ASD requires further research investigation, and relevant literature and research in Taiwan is still lacking. This article discusses lumbar degenerative disease, its indications, the contraindications of lumbar spine fusion surgery using ISOBAR, and related postoperative nursing care. We hope this article provides proper and new knowledge to clinical nurses for the care of patients undergoing lumbar spine fusion surgery with ISOBAR.

Posterior Dynamic Stabilization With Direct Pars Repair via Wiltse Approach for the Treatment of Lumbar Spondylolysis: The Application of a Novel Surgery.

A retrospective study to evaluate the clinical outcomes of a novel surgical method for treating patients with lumbar spondylolysis. The aim of this study was to investigate the effectiveness of posterior ISOBAR TTL stabilization of the lumbar spine with direct pars repair using Wiltse approach for the treatment of lumbar spondylolysis with or without slight spondylolisthesis and discuss the indications of this surgery. Surgical treatment of lumbar spondylolysis has yielded relatively good results. However, there are still many limitations of the current surgical methods, including, adjacent level degeneration, restricted indications, and soft tissue damage. Between August 2010 and January 2013, 13 (9 males and 4 females; mean age: 28.2 yrs), patients with lumbar spondylolysis with or without slight spondylolisthesis underwent posterior ISOBAR TTL stabilization of the lumbar spine, with direct pars repair via Wiltse approach. All patients were followed up for at least 24 months at outpatient visits or telephonically. Pre-operative and postoperative radiological assessments included anteroposterior, lateral and flexion extension radiographs, 3-dimensional reconstruction computed tomography (CT), and magnetic resonance imaging (MRI). Data pertaining to intraoperative blood loss, duration of operation, visual analog score (VAS), Oswestry disability index (ODI) scores, and other assessments were collected. The median follow-up duration was 36 months (range, 24-53 months). Surgery was successful in all patients with no complications; bony fusion of pars was confirmed on CT scan at postoperative 2 years. Significant pain relief was achieved in all patients including those with discogenic pain, those >30 years of age, and those with severe disc degeneration (P < 0.01). We evaluated a new surgical technique for the treatment of patients with spondylolysis with or without slight spondylolisthesis. Besides the good clinical results, the indications for this new surgery are much wider and can potentially overcome the limitations of earlier techniques. 4.

A Comparison of Outcome between Isobar TTL and Conventional Transforaminal Lumbar Interbody Fusion

Background Spine fusion using posterior instrumentation is currently considered the gold standard in surgical treatment for degenerative disease of the lumbar spine. Treatment-related problems for spinal fusion include stiffness, pseudoarthrosis, mechanical failure, and “adjacent segment disease (ASD).” The Isobar TTL is a form of pedicle screw–based dynamic stabilization (PDS) device. Several studies have shown the Isobar TTL to have good short-term outcomes in terms of fusion and decreasing the incidence of ASD. However, there are limited studies comparing the functional outcomes of the Isobar TTL with the conventional two-level transforaminal interbody fusion (TLIF). Methods This is a retrospective analysis of spine fusion and hybrid fusion cases done for degenerative lumbar disease in our institution during 2009 to 2012. Functional outcomes were measured preoperatively and at 12 and 24 months postoperatively using a 100-scaled visual analogue score (VAS), Oswestry Disability Index (ODI), and Short-Form 36 (SF-36) mental and physical components. Radiographic parameters to assess for ASD were also measured on standing lumbar films. These included disc height at the level of dynamic stabilization, disc height of the adjacent levels, foraminal height of the index level and adjacent levels, adjacent level disc angle, lumbar lordosis, and sacral slope. t test was used to analyze the data. p value of &lt; 0.05 was determined significant. Results A total of 30 cases were studied, 15 of which used Isobar TTL (Scient'x USA, Maitland, Florida, United States) treatment and 15 underwent a two-level TLIF. Mean length of follow-up was 24 months. VAS and ODI scores were slightly lower in the TLIF group at 12 and 24 months postoperatively ( p = 0.86). The SF-36 mental component was 5.51 points higher in the Isobar TTL group at 12 months post-op but was closer to TLIF values by the end of 24 months ( p = 0.8). SF-36 physical component was higher in the TLIF at both 12 ( p = 0.91) and 24 months ( p = 0.37). Disc height showed deterioration in both groups at 12 months postoperatively with a greater reduction in height in the Isobar TTL group ( p = 0.71). Disc angle was better preserved in the Isobar TTL group with an improvement of 1.3 and 0.61 degrees at 12 and 24 months, respectively. Lumbar lordosis was better preserved in the TLIF group with an increment of 1.36 degrees at 12 months ( p = 0.3) and 2.56 degrees at 24 months ( p = 0.77). The Isobar TTL group showed an initial reduction in lumbar lordosis by 3.4 degrees. This improved by 1.49 degrees at the end of 24 months. Among the radiographic parameters, only sacral slope was found to have a significant difference between the Isobar TTL and TLIF groups (mean difference 5.53, p = 0.03). Operation time was longer by 90.83 minutes in the Isobar TTL group ( p = 0.09). The duration of hospital stay was the same for all the patients with an average of 8.83 ± 5.71 days ( p = 0.94). Conclusions The Isobar TTL is a valid treatment option in the management of degenerative lumbar disease. Short-term results of the Isobar TTL are comparable to a two-level conventional TLIF in terms of functional and radiographic outcomes.

The experimental study of ISOBAR TTL dynamic stabilization system: the effect on lumbar segmental zygapophysial joint stress

Objective To study the effect of the TTL dynamic stabilization(DS)system on the zygapophysial joint stress(ZJS)of the lumbar motive segment. Methods Six fresh adult lumbar samples were tested. The L3- L4 segment,being studied in normal and disectomy state, was stabilized by TTL system. Insert pressure sensitive film(PSF)into the zygapophysial joint space, in the position of flexion 10°,extension 10°, left bending 10°, left rotation 10°, MTS provided 400 N axial load, then unloaded after maintaining the utmost load for about 1 min, pick out the PSF. Repeated testing for 3 times, then took the mean as the pressure value of that state.The image will be input in the computer to analyse. Results After stabilization, the ZJS decreased obviously in every state. In the TTL group, the ZJSin erection, flexion, extension and rotation state decreased to 4.01%, 0.74%, 3.78%, 3.45%, 19.6% of the axial load(400 N), and 24.99%, 17.23%, 17.0%, 18.40%, 35.99% of the normal state respectively. There existed statistical significence (P<0.05). After the disc was removed, the ZJS increased manifestly, but decreased obviously in flexion state. Conclusion TTL system can alleviate the ZJS of the fixed segment obviously. Key words: Lumbar; Motion preservation; Biomechanics; Zygapophysial joint

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

Pedicle screw‐based posterior dynamic stabilizers for degenerative spine: In vitro biomechanical testing and clinical outcomes

AbstractDynamic stabilization in a degenerate symptomatic spine may be advantageous compared with conventional fusion procedures, as it helps preserve motion and minimizes redistribution of loads at instrumented and adjacent segments. This article presents a systematic review of biomechanical and clinical evidence available on some of the pedicle screw based posterior dynamic stabilization (PDS) devices. Using Medline, Embase, and Scopus online databases, we identified four pedicle‐screw‐PDS devices for which both, biomechanical testing and clinical follow‐up data are available: Graf artificial ligaments, Isobar TTL, Polyetheretherketone rods, and Dynesys. The current state‐of‐the‐art of pedicle‐screw‐PDS devices is far from achieving its desired biomechanical efficacy, which has resulted in a weak support for the posited clinical benefits. Although pedicle‐screw‐PDS devices are useful in salvaging a moderately degenerate functionally suboptimal disc, for severe disc degeneration cases fusion is still the preferred choice. We conclude that a pedicle‐screw‐PDS device should aim at restoring load sharing amongst spinal elements while preserving the qualitative and quantitative nature of spinal motion, especially minimize posterior shift of the helical axis of motion. More precise and objective assessment techniques need to be standardized for in vivo evaluation of intervertebral motion and load sharing amongst spinal elements across different pedicle‐screw‐PDS devices. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3324–3340, 2014.

Finite element analysis of Isobar TTL techniques and universal spinal system for lumbar spine: a comparison

Objective To establish finite element models of universal spinal system(USS) and Isobar TTL on L3-S1 with fine anatomical structures and to compare the characteristics of stress distribution of the two models,so as to explore the influence of dynamic internal fixation system(DIFS) on the lumbar biomechanics,providing a theoretical basis for clinical application of DIFS. Methods The lumbar spine geometries were determined using the CT images of a 26-year-old healthy man.The finite element models of USS and Isobar TTL were constructed by using package Mimics 11.1,Geomagic studio 10.0,HyperMesh 10.0 and Abaqus 6.8.The ranges of motion,intervertebral disc stress of adjacent segments,and stress distribution and peak of internal fixation were recorded when the models were subjected to 150 N preload and 10 Nm moment of forces under different conditions: flexion,extension,lateral bending and axial rotation. Results We have successfully constructed the definite element model of L3-S1 with fine anatomical structures and the postoperation models of Isobar TTL and USS.The stress of Isobar TTL and USS model was mainly distributed on the screws,with the maximal stress on USS model being higher than that on the Isobar TTL model.The screws had high stress at the middle part,with the maximal stress being all less than 100 MPa under different conditions.The intervertebral stability of Isobar TTL model was not greatly different from that of normal model;however,the overall motion of USS model was obviously deceased,especially when at flexion and extension condition.For Isobar TTL model,the increases of intervertebral disc stress of adjacent segments of L3/L4 for forward bending,backward extension,lateral bending and rotation were 6.2%,9.7%,3.6%,and 3.8%,respectively,and the numbers for USS model were 8.5%,13.5%,4.3% and 4.8 %,respectively. Conclusion The maximal stress of Isobar TTL system can effectively maintain the range of motion of the lumbar spine,reduce the resistance of stress,and delay adjacent segment degeneration in theory.

Pedicle screw-based posterior dynamic stabilizers for degenerative spine: in vitro biomechanical testing and clinical outcomes

Dynamic stabilization in a degenerate symptomatic spine may be advantageous compared with conventional fusion procedures, as it helps preserve motion and minimizes redistribution of loads at instrumented and adjacent segments. This article presents a systematic review of biomechanical and clinical evidence available on some of the pedicle screw based posterior dynamic stabilization (PDS) devices. Using Medline, Embase, and Scopus online databases, we identified four pedicle-screw-PDS devices for which both, biomechanical testing and clinical follow-up data are available: Graf artificial ligaments, Isobar TTL, Polyetheretherketone rods, and Dynesys. The current state-of-the-art of pedicle-screw-PDS devices is far from achieving its desired biomechanical efficacy, which has resulted in a weak support for the posited clinical benefits. Although pedicle-screw-PDS devices are useful in salvaging a moderately degenerate functionally suboptimal disc, for severe disc degeneration cases fusion is still the preferred choice. We conclude that a pedicle-screw-PDS device should aim at restoring load sharing amongst spinal elements while preserving the qualitative and quantitative nature of spinal motion, especially minimize posterior shift of the helical axis of motion. More precise and objective assessment techniques need to be standardized for in vivo evaluation of intervertebral motion and load sharing amongst spinal elements across different pedicle-screw-PDS devices. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3324–3340, 2014.