Dynesys Group Research Articles

COMPARISON OF DYNESYS AND HYBRID SYSTEM FOR MULTI-SEGMENTAL LDD.

To compare effectiveness of Dynesys and hybrid system in treating patients with multi-segmental lumbar degenerative disease (LDD). Patients involved in this retrospective study were divided into Dynesys (n = 22) and Hybrid (n = 13) groups. Clinical outcomes were evaluated using Oswestry Disability Index (ODI), and Visual Analogue Scale (VAS). Radiologic evaluations included X-ray, MRI, and CT. Furthermore, different complications were analyzed. At the last follow-up, ODI and VAS of each group were improved (p < 0.05), and the range of motion (ROM) of operating segments decreased. However, Dynesys group preserved a larger extent of ROM at the final follow-up (p < 0.05). ROM of the upper adjacent segment was increased in both groups (p < 0.05), while the disc heights were decreased at the final follow-up (p < 0.05). Besides, Dynesys group had a more obvious decrease in the disc height of dynamic segments (p < 0.05). No significant difference existed in complications between both groups (p > 0. 05). In our study, similar satisfactory results were obtained in both groups. Both surgical procedures can be employed as effective treatments for middle-aged and physically active patients with multi-segmental LDD. Level of Evidence III; Retrospective Comparative Study.

Medium and long-term radiographic and clinical outcomes of Dynesys dynamic stabilization versus instrumented fusion for degenerative lumbar spine diseases

BackgroundDynesys stabilization (DS) is utilized to preserve mobility at the instrumental segments and prevent adjacent segment pathology in clinical practice. However, the advantages of DS method in medium and long-term follow-up remain controversial.ObjectiveTo compare the radiographic and clinical outcomes between DS and instrumented fusion in the treatment of degenerative lumbar spine disease with or without grade I spondylolisthesis with a minimum follow-up period of 2 years.MethodsWe conducted a comprehensive search of PubMed, EMBASE, Cochrane, and Web of Science databases, Chinese National Knowledge Databases, and Wanfang Database for potentially eligible articles. Clinical outcomes were assessed in terms of VAS and ODI scores, screw loosening and breakage, and surgical revision. Radiographic outcomes were assessed in terms of postoperative range of movement (ROM) and disc heigh. Moreover, adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis) were evaluated.ResultsSeventeen studies with 1296 patients were included in the meta-analysis. The DS group was associated with significantly lower postoperative VAS scores for low-back and leg pain, and lower rate of surgical revision than the fusion group. Moreover, the Dynesys group showed significantly less ASDeg than the fusion group but showed no significant advantage over the fusion group in terms of preventing ASDis. Additionally, the ROM at the stabilized segments of the fusion group decreased significantly and that at the adjacent segments increased significantly compared with those of the DS group.ConclusionDS showed comparable clinical outcomes and provided benefits in preserving the motion at the stabilized segments, thus limiting the hypermobility at the adjacent segments and preventing ASDeg compared with the fusion method in degenerative disease with or without grade I spondylolisthesis.

Evaluation of outcomes of discectomy with a dynamic neutralization system in treatment of lumbar disk herniation

ObjectiveThe study aimed to explore the clinical outcomes of discectomy with dynamic neutralization system (Dynesys) for single-segmental lumbar disk herniation (LDH) versus simple discectomy. MethodsThe eligible patients with single-segmental LDH were randomly divided into the discectomy with Dynesys group (group A) and the simple discectomy group (group B). The Oswestry disability index (ODI), visual analog score (VAS), radiological results of intervertebral height and range of motion (ROM) of the treated segment were evaluated pre- and post-operatively in both groups. Operation duration and blood loss were recorded. Complications, reoperation, and mortality were also assessed. All patients received a 2-year follow-up. Results123 (96.1%) participants completed the follow-up. The operation duration and blood loss of group B were significantly lower than those of group A (p<0.05). After operation, ODI and VAS were improved significantly in both groups, and there was no significant difference between the two groups immediately after surgery. But a rising trend was found in ODI and VAS of group B, especially after the 1-year follow-up (p<0.05). X-rays showed a continuing loss of intervertebral height of the treated segment in group B, while it was preserved in group A (p<0.05). ROM of the treated segment was also maintained stable in group A. ConclusionDiscectomy with Dynesys is safe and effective for LDH treatment.

Evaluation of outcomes of discectomy with a dynamic neutralization system in treatment of lumbar disk herniation

ObjectiveThe study aimed to explore the clinical outcomes of discectomy with dynamic neutralization system (Dynesys) for single-segmental lumbar disk herniation (LDH) versus simple discectomy. MethodsThe eligible patients with single-segmental LDH were randomly divided into the discectomy with Dynesys group (group A) and the simple discectomy group (group B). The Oswestry disability index (ODI), visual analog score (VAS), radiological results of intervertebral height and range of motion (ROM) of the treated segment were evaluated pre- and post-operatively in both groups. Operation duration and blood loss were recorded. Complications, reoperation, and mortality were also assessed. All patients received a 2-year follow-up. Results123 (96.1%) participants completed the follow-up. The operation duration and blood loss of group B were significantly lower than those of group A (p<0.05). After operation, ODI and VAS were improved significantly in both groups, and there was no significant difference between the two groups immediately after surgery. But a rising trend was found in ODI and VAS of group B, especially after the 1-year follow-up (p<0.05). X-rays showed a continuing loss of intervertebral height of the treated segment in group B, while it was preserved in group A (p<0.05). ROM of the treated segment was also maintained stable in group A. ConclusionDiscectomy with Dynesys is safe and effective for LDH treatment.

Comparison between Dynamic Stabilization and Instrumented Fusion in the Treatment of Spinal Stenosis with Degenerative Lumbar Scoliosis

Objective Posterior instrumented fusion is the most widely accepted surgical treatment for spinal stenosis with degenerative lumbar scoliosis (DLS). However, long fusion can affect daily activities due to lumbar stiffness. Dynamic stabilization has been introduced to overcome the drawbacks of fusion in recent years. This study aimed to compare the outcomes of dynamic stabilization (Dynesys system) with posterior instrumented fusion for the management of spinal stenosis with DLS. Methods This study retrospectively reviewed 65 consecutive patients with spinal stenosis and DLS who were undergoing surgical treatment between January 2013 and December 2017. Among them, 34 patients (Dynesys group) had fenestration decompression and Dynesys stabilization, whereas 31 patients (fusion group) underwent posterior instrumented fusion. Clinical outcomes, radiographic data, and postoperative complications were compared between the two groups. Results The mean number of fixed segments was 3.6 ± 0.9 in the Dynesys group and 4.2 ± 1.0 in the fusion group. Lower average values of operating time and blood loss were observed in the Dynesys group (P < 0.05). At an average follow-up of 42 months, there were no significant differences in the visual analog scale for the leg pain (VASleg), the scoliosis Cobb's angle, and the lumbar lordosis between the two groups (P > 0.05). The visual analog scale for back pain (VASback), oswestry disability index (ODI), and lumbar stiffness disability index (LSDI) scores of the Dynesys group were lower compared with the fusion group (P < 0.05). The range of motion (ROM) of implanted segments was significantly higher in the Dynesys group as compared to the fusion group (P < 0.05). The overall complications were less in the Dynesys group, but the difference was not statistically significant (P > 0.05). Conclusion Both dynamic stabilization and instrumented fusion can improve the clinical outcomes of patients with spinal stenosis and mild DLS. Compared to instrumented fusion, dynamic stabilization has the advantages of less invasion and motion preservation.

Implant failure following pedicle based dynamic stabilization of the lumbar spine

Pedicle-based dynamic stabilization (PBDS) devices such as Dynesys are promoted as an alternative and less invasive option for rigid stabilization of one and even more levels of the lumbar spine. Promising features of the Dynesys system, as well as shortcomings, became obvious in several clinical studies. Since 2012, we started using a new PBDS device as an alternative for the Dynesys, to avoid the screw loosening and the kyphosing effect. The objective is to compare failure rates between the Dynesys and Balan-C type PBDS implant and factors affecting outcome. In a retrospective study we investigated a total of 90 patients with lumbar pedicle screw dynamic stabilization (a group of 64 patiënts with Dynesys stabilization is compared to a group of 26 patients with Balan-C stabilization). Mean follow-up was 48 and 38 months, respectively. Using logistic regression analysis the impact of baseline characteristics such as gender, age, body mass index (BMI), indication for surgery, primary or revision surgery, single versus more level surgery, surgeon's experience and type of the implant on implant failure was analyzed. We found a statistically significant difference in failure rates between the two systems (13% in the Dynesys group versus 62% in the Balan-C group). In multivariate analysis, type of implant was associated with implant failure (odds ratio : 13). Our current results call for an optimization of the pre-and post-marketing surveillance of pedicle-based dynamic stabilization.

Multi-segmental lumbar spinal stenosis treated with Dynesys stabilization versus lumbar fusion in elderly patients: a retrospective study with a minimum of 5 years’ follow-up

Middle- and long-term outcomes of multi-segmental lumbar spinal stenosis treated with Dynesys stabilization (DS) have rarely been reported. Older age and multi-segmental degeneration may be positive factors in achieving satisfactory outcomes following DS. The present study aimed to compare the middle- and long-term outcomes of DS with lumbar fusion for treatment of multi-segmental lumbar spinal stenosis (ms-LSS) in elderly patients. This study retrospectively analyzed patients with ms-LSS treated by DS or lumbar fusion from January 2011 to April 2013. Twenty-two patients were included in the Dynesys group, and 44 patients treated by lumbar fusion and rigid fixation were included in the fusion group. Clinical outcomes were assessed by VAS and ODI. Radiological outcomes were measured by range of motion (ROM) of stabilized segments and the proximal adjacent segment, intervertebral disc height (DH) and L1-S1 lumbar lordosis angle (LL). Modified Pfirrmann grade score was used to access disc degeneration. The mean follow-up time of the Dynesys group and fusion group was 68.50 ± 6.40 and 70.14 ± 7.26months, respectively. Baseline data were similar between the two groups. There were no significant differences between the two groups in terms of improvement of clinical outcomes (VAS and ODI). DS preserved a certain degree of ROM (3.74 ± 2.00) of surgical segments. ROM of proximal adjacent segment underwent an increase in both groups at the final follow-up. The DH of the surgical segments and proximal adjacent segment in both groups was significantly lower than that before surgery (P = 0.000). LL of both groups improved (P = 0.000), and there was no significant difference between the two groups. The modified Pfirrmann score of proximal adjacent segment of both groups increased at the final follow-up. The fusion group underwent a more significant increase (P = 0.000), whereas the inter-group difference showed no significance (P = 0.090). DS is a safe and effective surgical treatment of multi-segmental lumbar spinal stenosis in the elderly population. DS preserves a certain degree of mobility of surgical segments.

Dynesys and posterior decompression and fusion internal fixation for the treatment of lumbar degenerative diseases: a systematic review

Meta analysis was used to evaluate the efficacy and safety of Dynesys and posterior decompression and fusion internal fixation for lumbar degenerative diseases. The computer was used to retrieve the Cochrane library, Medline, Embase, CNKI, Wanfang database and Chinese biomedical literature database; and the references and main Chinese and English Department of orthopedics journals were manually searched. All the prospective or retrospective comparative studies on the clinical efficacy and safety of Dynesys and posterior decompression and fusion internal fixation were collected, so as to evaluate the methodological quality of the study and to extract the data. The RevMan 5.2 software provided by Cochrane collaboration was used for systematic evaluation. A total of 9 clinical studies were included, including 3 prospective randomized controlled trials(RCT) and 6 retrospective controlled observational studies, which included 692 patients, with 336 cases in Dynesys group, and 356 cases in posterior decompression and fusion internal fixation (PLIF) group. The results showed that compared with PLIF, Dynesys system significantly decreased operation time(P<0.01), intraoperative blood loss (P<0.01). Both Dynesys and PLIF groups experienced improved ODI and back/leg pain VAS scores at final follow-up, and no statistically significant difference was noted according to the two surgical procedures(P>0.05). Dynesys could remain the range of motion (ROM) of surgical segments with less increased ROM of adjacent segments compared with that of PLIF group(P<0.01). Regarding the disc height of surgical segments, no statistically significant difference was noted according to the two groups(P>0.05), but postoperative complications incidence rate in PLIF group was higher than that in Dynesys group (P<0.05). Both Dynesys system and PLIF can improve clinical outcomes of lumbar degenerative diseases effectively. Compared with PLIF, Dynesys could remain the range of motion(ROM) of surgical segments with less increased ROM of adjacent segments and lower complication incidence rate. But the ability to prevent adjacent segments degeneration needs more RCTs with long-term follow-up to confirm.

Short-term effects of minimally invasive dynamic neutralization system for the treatment of lumbar spinal stenosis: An observational study.

The aim of the study was to evaluate the safety and short-term effects of dynamic stabilization via minimally invasive system for degenerative lumbar spinal stenosis. Patients with degenerative lumbar spinal stenosis and treated with Transforaminal Lumbar Interbody Fusion via minimally invasive minimally system (mis-TLIF) were served as the control group.From April 2011 to March 2015, 47 patients (29 male, 18 female; mean age 47.6 [range, 26–52] years) with lumbar spinal stenosis were treated with decompression and excision of herniated disk via the minimally invasive system combined with the dynamic fixation technique, and 42 patients as control group with mis-TLIF. Minimally invasive surgeries were performed via the posterior incision approach. The clinical outcomes were evaluated by comparing the Visual Analog Scale (VAS) score, Oswestry Disability Index (ODI) scores, and the ROMs of the adjacent segment before and after surgery. The postoperative complications related to the implants were identified.A total of 83 patients (43 of Dynesys group and 40 of mis-TLIF group) were followed for an average duration of >35 months. Dynesys stabilization resulted in significantly higher preservation of motion at the index level (P < .05), and significantly less hypermobility at the adjacent segments. VAS for the back and leg pain and ODI improved significantly (P < .05) in 2 groups; however, there is no significant difference between the groups. In Dynesys group, 3 cases suffered skin flay necrosis, 1 of them had a wound infection that was treated with washing and drainage combined with antibiotic therapy. Skin flay necrosis were also observed in 2 cases of mis-TLIF group. Reoperation was performed in one case of Dynesys group for rupture of the internal fixation. No rupture of internal fixation was observed in mis-TLIF group.The nonfusion fixation system Dynesys may be used to treat degenerative spinal stenosis without posterior element damage. This surgical technique is safe and effective. However, utilizing higher preservation of motion may lead to the failure of internal fixation.

Posterolateral fusion versus Dynesys dynamic stabilization: Retrospective study at a minimum 5.5 years’ follow-up

IntroductionLumbar fusion is one of the most widespread techniques to treat degenerative lumbar pathology. To prevent complications such as non-union or adjacent segment degeneration, dynamic stabilization techniques were developed, but with controversial results. The aim of the present study was to compare long-term radiologic and clinical results between fusion and dynamic stabilization. Material and methodsA single-center retrospective study included patients with recurrent lumbar discal hernia or lumbar canal stenosis managed by posterolateral fusion or by dynamic stabilization associated to neurologic release. Patients were seen in follow-up for radiological and clinical assessment: visual analog pain scale (VAS), Oswestry Disability Index (ODI), Short Form-12 (SF-12), adjacent segment disease (ASD), and intervertebral range of motion (ROM). ResultsFifty-eight patients were included: 25 in the fusion group (FG), and 33 in the Dynesys® group (DG). VAS scores were significantly lower in DG than FG. ODI was 14.6±2.8 in DG, versus 19.4±3.3 in FG (P=0.0001). SF-12 physical subscore was significantly higher in DG. ROM was 4.1±2° in DG, vs. 0.7±0.5° in FG (P=0.001). Radiologic ASD was significantly greater in FG than DG (36% vs. 12.1%; P=0.012), without difference in clinical expression (DG, 1 case; FG, 2 cases). ConclusionDynamic stabilization provided clinical and radiological results comparable to those of posterolateral fusion in these indications (although level L5-S1 was not studied). Level of evidenceIV.

Facet joint changes after application of lumbar nonfusion dynamic stabilization

OBJECTIVE The long-term effects on adjacent-segment pathology after nonfusion dynamic stabilization is unclear, and, in particular, changes at the adjacent facet joints have not been reported in a clinical study. This study aims to compare changes in the adjacent facet joints after lumbar spinal surgery. METHODS Patients who underwent monosegmental surgery at L4-5 with nonfusion dynamic stabilization using the Dynesys system (Dynesys group) or transforaminal lumbar interbody fusion with pedicle screw fixation (fusion group) were retrospectively compared. Facet joint degeneration was evaluated at each segment using the CT grading system. RESULTS The Dynesys group included 15 patients, while the fusion group included 22 patients. The preoperative facet joint degeneration CT grades were not different between the 2 groups. Compared with the preoperative CT grades, 1 side of the facet joints at L3-4 and L4-5 had significantly more degeneration in the Dynesys group. In the fusion group, significant facet joint degeneration developed on both sides at L2-3, L3-4, and L5-S1. The subjective back and leg pain scores were not different between the 2 groups during follow-up, but functional outcome based on the Oswestry Disability Index improved less in the fusion group than in the Dynesys group. CONCLUSIONS Nonfusion dynamic stabilization using the Dynesys system had a greater preventative effect on facet joint degeneration in comparison with that obtained using fusion surgery. The Dynesys system, however, resulted in facet joint degeneration at the instrumented segments and above. An improved physiological nonfusion dynamic stabilization system for lumbar spinal surgery should be developed.

Short term outcome of posterior dynamic stabilization system in degenerative lumbar diseases.

Background:Decompression and fusion is considered as the ‘gold standard’ for the treatment of degenerative lumbar diseases, however, many disadvantages have been reported in several studies, recently like donor site pain, pseudoarthrosis, nonunion, screw loosening, instrumentation failure, infection, adjacent segment disease (ASDis) and degeneration. Dynamic neutralization system (Dynesys) avoids many of these disadvantages. This system is made up of pedicle screws, polyethylene terephthalate cords, and polycarbonate urethane spacers to stabilize the functional spinal unit and preserve the adjacent motion after surgeries. This was a retrospective cohort study to compare the effect of Dynesys for treating degenerative lumbar diseases with posterior lumbar interbody fusion (PLIF) based on short term followup.Materials and Methods:Seventy five consecutive patients of lumbar degenerative disease operated between October 2010 and November 2012 were studied with a minimum followup of 2 years. Patients were divided into two groups according to the different surgeries. 30 patients underwent decompression and implantation of Dynesys in two levels (n = 29) or three levels (n = 1) and 45 patients underwent PLIF in two levels (n = 39) or three levels (n = 6). Clinical and radiographic outcomes between two groups were reviewed.Results:Thirty patients (male:17, female:13) with a mean age of 55.96 ± 7.68 years were included in Dynesys group and the PLIF group included 45 patients (male:21, female:24) with a mean age of 54.69 ± 3.26 years. The average followup in Dynesys group and PLIF group was 2.22 ± 0.43 year (range 2-3.5 year) and 2.17 ± 0.76 year (range 2-3 year), respectively. Dynesys group showed a shorter operation time (141.06 ± 11.36 min vs. 176.98 ± 6.72 min, P < 0.001) and less intraoperative blood loss (386.76 ± 19.44 ml vs. 430.11 ± 24.72 ml, P < 0.001). For Dynesys group, visual analogue scale (VAS) for back and leg pain improved from 6.87 ± 0.80 to 2.92 ± 0.18 and 6.99 ± 0.81 to 3.25 ± 0.37, (both P < 0.001) and for PLIF, VAS for back and leg pain also improved significantly (6.97 ± 0.84–3.19 ± 0.19 and 7.26 ± 0.76–3.56 ± 0.38, both P < 0.001). Significant improvement was found at final followup in both groups in Oswestry disability index (ODI) score (both P < 0.001). Besides, Dynesys group showed a greater improvement in ODI and VAS back and leg pain scores compared with the PLIF group (P < 0.001, P = 0.009 and P = 0.031, respectively). For radiological, height of the operated level was found increased in both groups (both P < 0.001), but there was no difference between two groups (P = 0.93). For range of motion (ROM) of operated level, significant decrease was found in both groups (P < 0.001), but Dynesys showed a higher preservation of motion at the operative levels (P < 0.001). However, no significant difference was found in the percentage change of ROM of adjacent levels between Dynesys and PLIF (0.74 ± 8.92% vs. 0.92 ± 4.52%, P = 0.91). Some patients suffered from degeneration of adjacent intervertebral disc at final followup, but there was no significant difference in adjacent intervertebral disc degeneration between two groups (P = 0.71). Moreover, there were no differences in complications between Dynesys and PLIF (P = 0.90), although the incidence of complication in Dynesys was lower than PLIF (16.67% vs. 17.78%).Conclusion:Dynamic stabilization system treating lumbar degenerative disease showed clinical benefits with motion preservation of the operated segments, but does not have the significant advantage on motion preservation at adjacent segments, to avoid the degeneration of adjacent intervertebral disk.

Dynesys Dynamic Stabilization Technique and Fusion Technique as Treatments for Degenerative Lumbar Disease: A Short-Term Comparative Clinical Study

Introduction More than 2 years after surgery, the short-term results of Dynesys dynamic stabilization technique and fusion technique used for the patients with degenerative lumbar disease were compared, to evaluate the efficacy of Dynesys system and its prevention for adjacent segment disease. Materials and Methods From December 2008 to November 2010, 70 patients who got single segment fixation underwent Dynesys dynamic stabilization, and then they were followed up for 24 to 47 months (average 33 months). The surgery duration, blood loss, hospital time, operative outcomes, ODI scores, VAS scores between preoperation and postoperation, and the ROM of operative segment and upper segment postoperatively were evaluated and compared with those of the 70 cases who got single segment lumbar spinal fusion in the same period. Results The pain and neurological function were improved obviously and there was no screws loosen, fracture, and displacement in both groups by the latest follow-up. When after 2 years postoperatively, outcomes of Dynesys group and fusion group were 93.15 and 90.67% retrospectively. Surgical duration, blood loss, and hospital time were less in Dynesys group than in fusion group; however, ODI and VAS scores were found no difference in the both groups. The ROM of operative segment was greater in Dynesys group than in fusion group; however, the ROM of upper segment was found no difference between the groups. Adjacent segment disease occurred in two cases (2/70, 2.9%) belonged to fusion group. Conclusion With right indications preoperationally, compared with fusion technique, Dynesys technique contributed to reducing operative invasion and hospital stay, getting the good efficacy. And whether it could reduce the incidence of adjacent segment disease needs more long-term follow-up. Disclosure of Interest None declared References Dubois G, de Germay B, Prere J, et al. Dynamic neutralisation: treatment of mobile vertebral instability. In: Spinal Restabilization Procedures. Amsterdam, The Netherlands: Elsevier; 2002:345–354 Lawhorne TW III, Girardi FP, Mina CA, Pappou I, Cammisa FP Jr. Treatment of degenerative spondylolisthesis: potential impact of dynamic stabilization based on imaging analysis. Eur Spine J 2009;18(6):815–822 Schwarzenbach O, Berlemann U. [Dynamic posterior stabilization with the pedicle screw system DYNESYS®]. Oper Orthop Traumatol 2010;22(5-6):545–557 Putzier M, Schneider SV, Funk J, Perka C. [Application of a dynamic pedicle screw system (DYNESYS) for lumbar segmental degenerations - comparison of clinical and radiological results for different indications]. Z Orthop Ihre Grenzgeb 2004;142(2):166–173 Klöckner C, Beck A. [Polysegmental Dynesys system]. Orthopade 2011;40(2):156–161 Di Silvestre M, Lolli F, Bakaloudis G, Parisini P. Dynamic stabilization for degenerative lumbar scoliosis in elderly patients. Spine 2010;35(2):227–234 Grob D, Benini A, Junge A, Mannion AF. Clinical experience with the Dynesys semirigid fixation system for the lumbar spine: surgical and patient-oriented outcome in 50 cases after an average of 2 years. Spine 2005;30(3):324–331 Bothmann M, Kast E, Boldt GJ, Oberle J. Dynesys fixation for lumbar spine degeneration. Neurosurg Rev 2008;31(2):189–196 Klöckner C. [Long-term results of the Dynesys implant]. Orthopade 2010;39(6):559–564 Němec F, Ryba L, Repko M, Chaloupka R. [Quality of life in the patients treated for degenerative lumbar spinal stenosis: a three-year follow-up study]. Acta Chir Orthop Traumatol Cech 2010;77(6):484–488 Hoppe S, Schwarzenbach O, Aghayev E, Bonel H, Berlemann U. Long-term outcome after monosegmental l4/5 stabilization for degenerative spondylolisthesis with the Dynesys device. J Spinal Disord Tech 2012 Yu SW, Yen CY, Wu CH, Kao FC, Kao YH, Tu YK. Radiographic and clinical results of posterior dynamic stabilization for the treatment of multisegment degenerative disc disease with a minimum follow-up of 3 years. Arch Orthop Trauma Surg 2012;132(5):583–589

Dynesys dynamic fixation and lumbar spinal fusion for treatment of lumbar degenerative disease: a clinical comparative study

Objective To evaluate the value of Dynesys dynamic fixation for treatment of lumbar degenerative disease by comparing with lumbar spinal fusion.Methods The clinical data of 60 patients with lumbar degenerative disease,who were treated in Changhai Hospital from June 2009 to June 2010,were retrospectively analyzed.Twenty-six patients,including 15 males and 11 females,with age ranging 32-56years(average[42.45±10.12]years),received Dynesys implantation for segments L4-L5(13cases)and L5-S1(13cases).Thirty-four patients,including 20 males and 14 females,with age ranging 38-60years(average[45.24±12.15]years),received fusion implantation for segments L4-L5(18cases)and L5-S1(16cases).The following parameters were observed and compared between the two groups:operation time,blood loss,hospital stay,preoperative Oswestry disability index(ODI),ODI at last follow-up,low back and leg pain visual analogue scale(VAS),results of health status questionnaire(SF-36),segmental angulation degree of lumbar spine,and intervertebral height.Results All the 60 patients were followed up for 3-4years(average[3.2±0.2]years).The operation time and intra-operative blood loss were significantly different between the two groups(P0.05),and no difference was found for average hospital days.The ODI,VAS,and SF-36 clinical scores at last follow-up were significantly improved compared with those before operation in the two groups(P0.01),with the improvement in Dynesys group being more significant than the fusion group(P0.01).The segmental angulation degree of lumbar spine had no noticeable improvement in the two groups at last followup,and there were no significant differences between the two groups.There was no intervertebral height loss at the last follow-up in the two groups,and there was no significant difference in intervertebral heights between the two groups.ConclusionDynesys dynamic lumbar fixation shows no more advantages in terms of radiological results compared with the fusion group.Moreover,fusion fixation is not suggested to have more adjacent segment degeneration(ASD)than Dynesys dynamic lumbar fixation.But clinically Dynesys dynamic lumbar fixation yields a greater improvement,with the advantages of less bleeding and shorter operation time.In middle-aged and elderly patients with degenerative diseases,Dynesys dynamic lumbar fixation is an acceptable choice.

An in vivo kinematic comparison of dynamic lumbar stabilization to lumbar discectomy and posterior lumbar fusion using radiostereometric analysis

BackgroundBiomechanical studies have shown that dynamic stabilization restores the neutral zone and stabilizes the motion segment. Unfortunately, there are limitations to clinical measurement of lumbar motion segments when using routine radiographs. Radiostereometric analysis is a 3-dimensional technique and can measure the spinal motion segment more accurately than techniques using plain film radiographs. The purpose of this study was measure and compare the range of motion after dynamic stabilization, posterior lumbar fusion (PLF), and lumbar discectomy. MethodsFour patients who underwent lumbar decompression and dynamic stabilization (Dynesys; Zimmer Spine, Inc., Warsaw, Indiana) for treatment of lumbar spondylosis were compared with 4 patients with a similar diagnosis who were treated by PLF and pedicle screw fixation (PLF group) and 8 patients who had undergone lumbar microdiscectomy (discectomy group) for treatment of radiculopathy. During the surgical procedure, 3 to 5 tantalum beads were placed into each of the operative segments. The patients were followed up postoperatively at 1 month, 1 year, and 2 years. At each follow-up time point, segmental motions (flexion, extension, and total sagittal range of motion [SROM]) were measured by radiostereometric analysis. ResultsFlexion, extension, and SROM measured 1.0° ± 0.9°, 1.5° ± 1.3°, and 2.3° ± 1.2°, respectively, in the Dynesys group; 1.0° ± 0.6°, 1.1° ± 0.9°, and 1.5° ± 0.6°, respectively, in the PLF group; and 2.9° ± 2.4°, 2.3° ± 1.5°, and 4.7° ± 2.2°, respectively, in the discectomy group. No significant difference in motion was seen between the Dynesys and PLF groups or between the Dynesys and discectomy groups in extension. Significant differences in motions were seen between the PLF and discectomy groups and between the Dynesys and discectomy groups in flexion (P = .007) and SROM (P = .002). There was no significant change in the measured motions over time. ConclusionsIn this study a significantly lower amount of motion was seen after dynamic stabilization and PLF when compared with discectomy. A future study with a larger cohort is necessary to examine what effect, if any, these motions have on clinical outcomes.

Radiographic and clinical results of posterior dynamic stabilization for the treatment of multisegment degenerative disc disease with a minimum follow-up of 3 years

This study aims to compare radiographic and clinical outcomes of Dynesys and posterior lumbar interbody fusion (PLIF) for the treatment of multisegment disease. Thirty-five consecutive patients who received Dynesys implantation at three levels from L1 to S1 from November 2006 to July 2007 were studied. A retrospective analysis of the medical records of 25 patients with the same indications who received 3-level PLIF (L1-S1) was also conducted. Radiographic and clinical outcomes between the groups were compared. All patients included in the analysis completed 3-year follow-up. Dynesys stabilization resulted in higher preservation of motion at the operative levels, as well as total range of motion from L1 to S1. A decrease of anterior disc height was seen in the Dynesys group and an increase was seen in the PLIF group. An increase in posterior disc height was noted in both groups; however, was greater in the PLIF group at 3 years. The Dynesys group showed a greater improvement in Oswestry Disability Index and visual analogue scale back pain scores at 3 years postoperatively. There were no differences in complications between the two groups. In conclusion, Dynesys is an acceptable alternative to PLIF for the treatment of multisegment lumbar disease.

Adjacent Segment Mobility After Rigid and Semirigid Instrumentation of the Lumbar Spine

Retrospective radiographic analysis of lumbar spine range of motion (ROM) after monosegmental fusion and posterior dynamic stabilization at the level L4-L5. Comparison of segmental ROM at the index level and the cranial and caudal adjacent levels and of global lumbar spine ROM after monosegmental fusion and posterior dynamic stabilization. The postulated advantage of nonfusion technology compared with fusion is based on the assumption that preservation of motion at the treated segment reduces the incidence of adjacent segment effects. Therefore, it is imperative to provide evidence that dynamic stabilization devices avoid hypermobility at the adjacent segments because this might substantiate a protective effect on the adjacent segments. Twenty-six patients with low back pain and claudication due to degenerative instability at the level L4-L5 with concomitant spinal stenosis were treated either with decompression and Dynesys (n = 11) or with decompression and fusion (n = 15). All patients underwent flexion/extension radiographs before surgery and at latest follow-up. ROM was assessed at the index level (L4-L5), the cranial/caudal adjacent levels (L3-L4/L5-S1), and at the lumbar spine from L2 to S1. There was a significant reduction of the global ROM of the lumbar spine (L2-S1) and the segmental ROM at the index level (L4-L5) in the fusion group, whereas adjacent level ROM did not change significantly. In the Dynesys group, no significant changes of global lumbar spine ROM (L2-S1) and segmental ROM (index level and cranial/caudal adjacent levels) were seen. This study shows that neither monosegmental instrumented fusion nor monosegmental posterior dynamic stabilization with Dynesys alter the ROM of the cranial and caudal adjacent levels. Consequently, monosegmental posterior dynamic stabilization with Dynesys has no effect with regard to adjacent segment mobility compared with monosegmental fusion.