Risk factor analysis of adjacent segment disease requiring surgery after short lumbar fusion: the influence of rheumatoid arthritis

Complications After Open Reduction and Internal Fixation for Distal Radius Fractures in Patients With and Without Rheumatoid Arthritis

PURPOSE

Rheumatoid arthritis (RA) can have severe impact on patients' functional abilities and increase the risk of fragility fractures. Little is known about how patients with RA fare after operative management of distal radius fractures. The purpose of this study was to compare postoperative complications after surgical fixation in patients with RA and controls, hypothesizing that patients with RA would have higher levels of postoperative complications.

METHODS

Patients were identified using Current Procedural Terminology and International Classification of Diseases, Ninth and Tenth Revision, codes for open treatment of distal radius fractures and RA at 3 level 1 trauma centers over a 5-year period (2015-2019). Chart abstraction provided details regarding injuries and treatment. Age- and sex-matched controls were identified in a 2:1 ratio. Postoperative complications were classified according to the Clavien-Dindo-Sink classification system and divided into early (less than 90 days) and late groups.

RESULTS

Sixty-four patients (21 with RA and 43 controls) were included. The patients were predominantly women, with a mean age of 62 years and a mean Charlson comorbidity index of 2.1. The RA medications at the time of injury included conventional synthetic disease-modifying antirheumatic drugs (5/21), biologic disease-modifying antirheumatic drugs (5/21), or chronic oral prednisone (6/21). Rheumatoid medications, except hydroxychloroquine, were withheld for 2-3 weeks after surgery. Rheumatoid patients were significantly more likely to sustain a complication compared with the control group, although this was no longer significant on adjusted analysis. Class I complications were the most common. The incidence of early versus late complications was similar between the groups. A high rate of early return to surgery for fixation failure occurred in the RA group compared with none in the control group.

CONCLUSIONS

Patients with RA undergoing operative management of distal radius fractures are at risk of postoperative complications, particularly fracture fixation failure, necessitating return to the operative room. High levels of pain, stiffness, and mechanical symptoms were noted in the RA group.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Failed Back Surgery Syndrome: No Longer a Surgeon's Defeat-A Narrative Review

The introduction of the term Persistent Spinal Pain Syndrome (PSPS-T1/2), replacing the older term Failed Back Surgery Syndrome (FBSS), has significantly influenced our approach to diagnosing and treating post-surgical spinal pain. This comprehensive review discusses this change and its effects on patient care. Various diagnostic methods are employed to elucidate the underlying causes of back pain, and this information is critical in guiding treatment decisions. The management of PSPS-T1/2 involves both causative treatments, which directly address the root cause of pain, and symptomatic treatments, which focus on managing the symptoms of pain and improving overall function. The importance of a multidisciplinary and holistic approach is emphasized in the treatment of PSPS-T1/2. This approach is patient-centered and treatment plans are customized to individual patient needs and circumstances. The review concludes with a reflection on the impact of the new PSPS nomenclature on the perception and management of post-surgical spinal pain.

Biomechanical Evaluation of Lateral Lumbar Interbody Fusion with Various Fixation Options for Adjacent Segment Degeneration: A Finite Element Analysis

OBJECTIVE

Adjacent segment degeneration (ASD) is a common phenomenon after lumbar fusion. Lateral lumbar interbody fusion (LLIF) may provide an alternative treatment method for ASD. This study used finite element analysis to evaluate the biomechanical effects of LLIF with various fixation options and identify an optimal surgical strategy for ASD.

METHODS

A validated L1-S1 finite element model was modified for simulation. Six finite element models of the lumbar spine were created and were divided into group 1 (L4-5 posterior lumbar interbody fusion [PLIF] + L3-4 LLIF) and group 2 (L5-S1 PLIF + L4-5 LLIF). Each group consisted of 1) cage-alone, 2) cage + lateral screw fixation (LSF), and 3) cage + bilateral pedicle screw fixation (BPSF) models. The range of motion, intradiscal pressure, and facet loads of adjacent segments as well as interbody cage stress were analyzed.

RESULTS

The stress on the LLIF cage-superior endplate interface was highest in the cage-alone model followed by the cage + LSF model and cage + BPSF model. The increase in range of motion, intradiscal pressure, and facet loads at the adjacent segment was highest in the cage + BPSF model followed by the cage + LSF model and cage-alone model. However, the biomechanical effect on the adjacent segment seemed similar in the cage-alone and cage + LSF models.

CONCLUSIONS

LLIF with BPSF is recommended when performing LLIF surgery for ASD after L4-5 and L5-S1 PLIF. Considering cage subsidence and biomechanical effects on the adjacent segment, LLIF with LSF may be a suboptimal option for ASD surgery.

Biomechanical evaluation of a short-rod technique for lumbar fixation surgery

Objective: The purpose of this study was to analyze the stability and instrument-related complications associated with fixation of the lumbar spine using the Short-Rod (SR) technique.

Methods: Using finite element analysis, this study assessed the stability of a bilateral lumbar fixation system when inserting the pedicle screws at angles of 10°, 15°, and 20° to the endplate in the sagittal plane. Using the most stable construct with a screw angle, the model was then assessed with different rod lengths of 25, 30, 35, and 45 mm. The optimal screw inclination angle and rod length were incorporated into the SR model and compared against traditional parallel screw insertion (pedicle screws in parallel to the endplate, PPS) in terms of the stability and risk of instrument-related complications. The following parameters were evaluated using the validated L4–L5 lumbar finite element model: axial stiffness, range of motion (ROM), stress on the endplate and facet joint, von-Mises stress on the contact surface between the screw and rod (CSSR), and screw displacement.

Results: The results showed that the SR model with a 15° screw inclination angle and 35 mm rod length was superior in terms of construct stability and risk of complications. Compared to the PPS model, the SR model had lower stiffness, lower ROM, less screw displacement, and lower stress on the facet cartilage, the CSSR, and screws. However, the SR model also suffered more stress on the endplate in flexion and lateral bending.

Conclusion: The SR technique with a 15° screw inclination and 35 mm rod length offers good lumbar stability with a low risk of instrument-related complications.

The Influence of Rheumatoid Arthritis on Higher Reoperation Rates over Time Following Lumbar Spinal Fusion-A Nationwide Cohort Study

This study aimed to compare the rates of reoperation over time following first lumbar fusion in rheumatoid arthritis (RA) patients and non-RA patients. This study was conducted using Korean Health Insurance Review and Assessment (HIRA) data. We identified the RA group as 2239 patients who underwent their first lumbar fusion with RA and the control group as 11,195 patients without RA. This reflects a ratio of 1:5, and the participants were matched by sex, age, and index surgery date. The index dates were between 2012 and 2013. When comparing the rate of patients undergoing reoperation, the adjusted HR was 1.31 (95% CI: 1.10−1.6) in the RA group (p = 0.002). In terms of the three time intervals, the values in the time frames of <3 months and 3 months−1 year were not statistically significant. However, at 1 year post-surgery, there was a higher risk of reoperation in the RA group, as demonstrated by the Kaplan−Meier cumulative event analysis. This higher risk of reoperation continued to increase throughout 5 years of follow-up, after which it was stable until the last follow-up at 7 years. This population-based cohort study showed that the RA patients had a 1.31 times higher risk of reoperation following lumbar fusion than did the controls. This difference was more pronounced at 1 year post-surgery.

Postoperative outcomes after degenerative lumbar spine surgery in rheumatoid arthritis patients -a propensity score-matched analysis

Background

Although treatment options for rheumatoid arthritis (RA) have evolved significantly since the introduction of biologic agents, degenerative lumbar disease in RA patients remains a major challenge. Well-controlled comparisons between RA patients and their non-RA counterparts have not yet been reported. The objective of the present study was to compare postoperative outcomes of lumbar spine surgery between RA and non-RA patients by a retrospective propensity score-matched analysis.

Methods

Patients who underwent primary posterior spine surgery for degenerative lumbar disease in our prospective multicenter study group between 2017 and 2020 were enrolled. Demographic data including age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) physical status classification, diabetes mellitus, smoking, steroid usage, number of spinal levels involved, and preoperative patient-reported outcome (PRO) scores (numerical rating scale [NRS] for back pain and leg pain, Short Form-12 physical component summary [PCS], EuroQOL 5-dimension [EQ-5D], and Oswestry Disability Index [ODI]) were used to calculate a propensity score for RA diagnosis. One-to-one matching was performed and 1-year postoperative outcomes were compared between groups.

Results

Among the 4567 patients included, 90 had RA (2.0%). RA patients in our cohort were more likely to be female, with lower BMI, higher ASA grade and lower current smoking rate than non-RA patients. Preoperative NRS scores for leg pain, PCS, EQ-5D, and ODI were worse in RA patients. Propensity score matching generated 61 pairs of RA and non-RA patients who underwent posterior lumbar surgery. After background adjustment, RA patients reported worse postoperative PCS (28.4 vs. 37.2, p = 0.008) and EQ-5D (0.640 vs. 0.738, p = 0.03), although these differences were not significant between RA and non-RA patients not on steroids.

Conclusions

RA patients showed worse postoperative quality of life outcomes after posterior surgery for degenerative lumbar disease, while steroid-independent RA cases showed equivalent outcomes to non-RA patients.

Incidence of and risk factors for spondylolisthesis, scoliosis, and vertebral fracture in rheumatoid arthritis

INTRODUCTION

Although lumbar lesions such as spondylolisthesis, scoliosis, and vertebral fracture are not specific to rheumatoid arthritis (RA), the prevalence is high in RA patients. However, no longitudinal study has evaluated lumbar lesions in RA. This study aimed to investigate the incidence of and risk factors for lumbar lesions in RA by a prospective longitudinal cohort study.

MATERIALS AND METHODS

The study cohort comprised 110 patients with RA from the 'analysis of factors for RA spinal disorders (AFFORD)' study who completed the secondary survey at a single orthopaedic outpatient RA clinic. Radiological examination included standing radiographs and magnetic resonance imaging (MRI) of the lumbar spine. New development of spondylolisthesis, scoliosis, and vertebral fracture were assessed between baseline and secondary survey.

RESULTS

The incidences of spondylolisthesis, scoliosis, and vertebral fracture were 42%, 16%, and 12%, respectively, during a mean follow-up of 7 years. The independent risk factor for de novo scoliosis was poor control of RA (adjusted odds ratio [aOR] 4.81, p = 0.011), while the independent risk factors for new vertebral fracture was use of glucocorticoid at secondary survey (aOR 14.87, p = 0.012). Patients with de novo scoliosis exhibited more severe low back pain and lower quality of life than those without.

CONCLUSION

The incidence of scoliosis was related in patients with poor control of RA, while new vertebral fracture was more common in patients with use of glucocorticoid. Control of disease activity might be important in preventing radiological lumbar disorders in RA.

Surgical risk factors associated with the development of adjacent segment pathology in the lumbar spine

Adjacent segment pathology (ASP) is a major cause of disability, and the recognition of the surgical risk factors associated with the development of this condition is essential for its prevention.

Different surgical approaches, from decompression without fusion to non-instrumented and instrumented fusion, have distinct contributions to the development of ASP.

Although motion-preservation procedures could reduce the prevalence of ASP, these are also associated with a higher percentage of complications.

Several risk factors associated with previous surgery, namely the chosen surgical approach and anatomical dissection, the choice of interbody fusion, the increment and length of the fusion, and the restoration of sagittal alignment, may influence the development of ASP.

Cite this article: EFORT Open Rev 2021;6:966-972. DOI: 10.1302/2058-5241.6.210050

Patient-Related Risk Factors for the Development of Lumbar Spine Adjacent Segment Pathology

Objectives

Individual risk factors for the development of adjacent segment pathology (ASP) need to be investigated and identified to address possible modifiable factors in advance and improve outcomes and reduce medical costs. This study aimed to review the literature regarding patient-related risk factors and sagittal alignment parameters associated with ASP development.

Methods

The authors performed an extensive review of the literature addressing the objectives mentioned earlier.

Results

Certain patient factors such as age, gender, obesity, preexisting degeneration, osteoporosis, postmenopausal state, rheumatoid arthritis, and facet tropism may contribute to adjacent segment degeneration. Genetic influences, such as polymorphisms of the vitamin D receptor and collagen IX genes, can also be a potential cause for disc degeneration with consequent deterioration of the motion segment.The influence of sagittal imbalances, particularly after lumbar fusion, is a significant parameter to be taken into account as an independent risk factor for ASP development.

Conclusions

Patient-specific risk factors, such as age, gender, obesity, preexisting degeneration, and genetic features increase the likelihood of developing ASP. On the other hand, sagittal alignment plays a significant role in the development of this condition.

The radiological outcome in lumbar interbody fusion among rheumatoid arthritis patients: a 20-year retrospective study

BACKGROUND

Clinical outcomes amongst Rheumatoid Arthritis (RA) patients have shown satisfactory results being reported after lumbar surgery. The increased adoption of the interbody fusion technique has been due to a high fusion rate and less invasive procedures. However, the radiographic outcome for RA patients after receiving interbody fusion has scarcely been addressed in the available literature.

METHODS

Patients receiving interbody fusion including ALIF, OLIF, and TLIF were examined for implant cage motion and fusion status at two-year follow-up. Parameters for the index correction level including ADH, PDH, WI, SL, FW, and FH were measured and compared at pre-OP, post-OP, and two-year follow-up.

RESULTS

We enrolled 64 RA patients at 104 levels (mean 64.0 years old, 85.9% female) received lumbar interbody fusion. There were substantial improvement in ADH, PDH, WI, SL, FW, and FH after surgery, with both ADH and PDH having significantly dropped at two-year follow up. The OLIF group suffered from a higher subsidence rate with no significant difference in fusion rate when compared to TLIF. The fusion rate and subsidence rate for all RA patients was 90.4 and 28.8%, respectively.

CONCLUSIONS

We revealed the radiographic outcomes of lumbar interbody fusions towards symptomatic lumbar disease in RA patients with good fusion outcome despite the relative high subsidence rate amongst the OLIF group. Those responsible for intra-operative endplate management should be more cautious to avoid post-OP cage subsidence.

[Study of modified subcutaneous lumbar spine index as a predictor for short-term effectiveness in transforaminal lumbar interbody fusion]

Objective

To explore the value of modified subcutaneous lumbar spine index (MSLSI) as a predictor for short-term effectiveness of transforaminal lumbar interbody fusion (TLIF) in treatment of lumbar degenerative disease (LDD).

Methods

Between February 2014 and October 2019, 450 patients who were diagnosed as LDD and received single-segment TLIF were included in the study. Based on the MSLSI measured by preoperative lumbar MRI, the patients were sorted from small to large and divided into three groups ( n=150). The MSLSI of group A was 0.11-0.49, group B was 0.49-0.73, and group C was 0.73-1.88. There was no significance in gender, age, disease duration, diagnosis, surgical segment, and improved Charlson comorbidity index between groups ( P>0.05). There were significant differences in the subcutaneous adipose depth of the L ₄ vertebral body and body mass index (BMI) between groups ( P<0.05). The operation time, intra-operative blood loss, length of incision, drainage tube placement time, drainage volume on the 1st day after operation, drainage volume on the 2nd day after operation, total drainage volume, antibiotic use time after operation, walking exercise time after operation, hospital stay, the incidences of surgical or non-surgical complications in the three groups were compared. Pearson correlation analysis was used to analyze the correlation between MSLSI and BMI, and partial correlation analysis was used to study the relationship between MSLSI, BMI, improved Charlson comorbidity index, subcutaneous adipose depth of the L ₄ vertebral body and complications. The Receiver Operating Characteristic (ROC) curve was used to evaluate the value of SLSI and MSLSI in predicting the occurrence of complications after TLIF in treatment of LDD.

Results

There was no significant difference in operation time, length of incision, antibiotic use time after operation, walking exercise time after operation, drainage tube placement time, drainage volume on the 1st day after operation, drainage volume on the 2nd day after operation, and total drainage volume between groups ( P>0.05). The amount of intra-operative blood loss in group C was higher than that in groups A and B, and the hospital stay was longer than that in group B, with significant differences ( P<0.05). Surgical complications occurred in 22 cases (14.7%), 25 cases (16.7%), and 39 cases (26.0%) of groups A, B, and C, respectively. There was no significant difference in the incidence between groups ( χ ²=0.826, P=0.662). The incidences of nerve root injury and wound aseptic complications in group C were higher than those in groups A and B, and the incidence of nerve root injury in group B was higher than that in group A, with significant differences ( P<0.05). There were 13 cases (8.7%), 7 cases (4.7%), and 11 cases (7.3%) of non-surgical complications in groups A, B, and C, respectively, with no significant difference ( χ ²=2.128, P=0.345). There was no significant difference in the incidences of cardiovascular complications, urinary system complications, central system complications, and respiratory system complications between groups ( P>0.05). There was a correlation between MSLSI and BMI in 450 patients ( r=0.619, P=0.047). Partial correlation analysis showed that MSLSI was related to wound aseptic complications ( r=0.172, P=0.032), but not related to other surgical and non-surgical complications ( P>0.05). There was no correlation between BMI, improved Charlson comorbidity index, subcutaneous adipose depth of the L ₄ vertebral body and surgical and non-surgical complications ( P>0.05). ROC curve analysis showed that the area under ROC curve (AUC) of MSLSI was 0.673 (95%CI 0.546-0.761, P=0.025), and the AUC of SLSI was 0.582 (95%CI 0.472-0.693, P=0.191).

Conclusion

MSLSI can predict the short-term effectiveness of TLIF in treatment of LDD. Patients with high MSLSI suffer more intra-operative blood loss, longer hospital stay, and higher incidence of nerve root injury and postoperative incision complications.

Long-Term Results of Anterior-Only Lumbar Interbody Fusions in Rheumatoid Arthritis Patients: Comparative Retrospective Cohort Study

OBJECTIVE

Rheumatoid arthritis (RA) is a risk factor of lumbar spine surgical failure. The interest of anterior lumbar fusion in this context remains unknown. This retrospective study aimed to compare the outcome of anterior-only fusions between RA patients and non-RA (NRA) patients to treat lumbar spine degenerative disorders.

METHODS

NRA and RA groups including anterior-only fusion were compared. Clinical data (Visual Analog Scale score axial back pain scale, the Oswestry Disability Index, and a questionnaire of satisfaction regarding the surgical result); radiologic data (bone fusion, sagittal balance analysis); and adverse events were assessed using repeated measure 1-way analysis of variance.

RESULTS

The mean follow-up was 9.5 years (95% confidence interval [7.1-12.2]) for the RA group (n = 13) and 9.4 years (95% confidence interval [8.7-10.3]) for the NRA group (n = 36). Anterior fusion improved clinical outcome without any effect of RA (Visual Analog Scale score axial back pain scale; P < 0.001/Oswestry Disability Index; P = 0.01). The presence of RA influenced neither the satisfaction as the regards the surgical result nor spine balance nor bone fusion. Context of RA increased the surgical revision rate (10 patients [76.9%] for RA group vs. 3 patients [8.8%] for the NRA group; P = 0.001) because of the occurrence of an adjacent segment disease needing surgical revision (P = 0.028), especially the occurrence of intervertebral frontal dislocation (P = 0.02).

CONCLUSIONS

As noticed for posterior-only fusion, the anterior lumbar approach in RA patients does not seem to avoid the occurrence of an adjacent segment disease.

Radiological and clinical comparisons of the patients with rheumatoid arthritis operated with rigid and dynamic instrumentation systems due to lumbar degenerative spinal diseases

BACKGROUND

It is extremely difficult to treat spine disorders with stabilization in patients with rheumatoid arthritis. Because revision rates are significantly higher in rigid stabilization. To date, there is no data about patients with rheumatoid arthritis treated with dynamic stabilization. Our aim was to compare the radiological and clinical results of patients with rheumatoid arthritis who underwent lumbar rigid stabilization or dynamic stabilization with Polyetheretherketone rod (PEEK).

METHODS

Patients with degenerative lumbar spine disease with rheumatoid arthritis who underwent dynamic stabilization between 2013 and 2015 and rigid stabilization between 2010 and 2012 were evaluated radiologically for adjacent segment disease, proximal junctional kyphosis, system problem (nonunion, screw loosening, instrumentation failure, pull out). It was also compared according to both the revision rates and the Visual Analog Scale and Oswestry Disability Index scores at the 12th month and 24th month.

RESULTS

The difference of decrease in Visual Analog Scale and Oswestry Disability Index scores from preoperative to 12th month between patients who underwent dynamic stabilization and rigid stabilization was statistically insignificant. However, there was a significant difference of increase in Visual Analog Scale and Oswestry Disability Index scores between the 12th month and 24th month of patients who underwent rigid stabilization, compared with patients with dynamic stabilization. In patients with dynamic stabilization, the problems of instrumentation were seen less frequently. Revision rates were high in patients with rigid stabilization when compared the patients with dynamic stabilization.

CONCLUSION

Radiological and clinical outcomes in patients with rheumatoid arthritis operated with dynamic stabilization are more significant when compared to rigid stabilization. These patients have lower pain and disability scores in their follow up periods. Revision rates are lower in patients with dynamic stabilization.

A Study to Compare the Efficacy of a Biodegradable Dynamic Fixation System With Titanium Devices in Posterior Spinal Fusion Between Articular Processes in a Canine Model

The objective of this study was to apply a biodegradable dynamic fixation system (BDFS) for lumbar fusion between articular processes and compare the fusion results and biomechanical changes with those of conventional rigid fixation. Twenty-four mongrel dogs were randomly assigned to 2 groups and subjected to either posterior lumbar fusion surgery with a BDFS or titanium rods (TRs) at the L5-L6 segments. Six animals in each group were sacrificed at 8 or 16 weeks. Fusion conditions were evaluated by computed tomography (CT), manual palpation, biomechanical tests, and histological analysis. Biomechanical tests were performed at the L4-7 (for range of motion (ROM)) and L5-6 (for fusion stiffness) segments. Histological examination was performed on organs, surrounding tissues, and the fused area. The magnesium alloy components maintained their initial shape 8 weeks after the operation, but the meshing teeth were almost completely degraded at 16 weeks. The biomechanical analysis revealed an increased lateral bending ROM at 8 weeks and axial torsion ROM at 16 weeks. The L4-5 extension-flexion ROMs in the BDFS group were 2.29 ± 0.86 deg and 3.17 ± 1.08 deg at 16 weeks, respectively, compared with 3.22 ± 0.56 deg and 5.55 ± 1.84 deg in TR group. However, both groups showed similar fusion results. The BDFS design is suitable, and its degradation in vivo is safe. The BDFS can be applied for posterior lumbar fusion between articular processes to complete the fusion well. Additionally, the BDFS can reduce the decline in lateral motion and hypermotion of the cranial adjacent segment in flexion-extension motion.

[Research progress in effect of obesity on the effectiveness of posterior lumbar fusion]

Objective

To review the effect of obesity on the effectiveness of posterior lumbar fusion in patients with lumbar degenerative diseases (LDD).

Methods

The related literature at home and abroad was extensively reviewed. And the difficulty of operation, risk of complications, and long-term effectiveness of posterior lumbar fusion for obese patients with LDD were summarized.

Results

Although some relevant literature suggest that the posterior lumbar fusion for obese patients is difficult and the risk of postoperative complications is high, the overall research results do not suggest that obesity is a risk factor for the implementation of posterior lumbar fusion. By assessing the physical condition of patients and strictly grasping the surgical indications, obese patients can obtain good surgical efficacy.

Conclusion

Posterior lumbar fusion is an effective method for the treatment of LDD in obese patients. However, relevant studies need to be completed to further evaluate the safety and efficacy of posterior lumbar fusion for obese patients.

Does Rheumatoid Arthritis Affect the Infection and Complications Rates of Spinal Surgery? A Systematic Review and Meta-Analysis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that produces synovial membrane inflammation and causes progressive articular damage with function loss. Some controversy exists regarding whether RA is associated with infection and complications after spinal surgery. The present study aimed to determine the effect of RA on spinal surgery infection and complications.

METHODS

A systematic literature search was performed in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. All studies that had compared patients who had undergone spinal surgery with and without RA were included in the analysis.

RESULTS

We found significantly greater rates statistically of complications (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.20-1.70; P < 0.05) and infections (OR, 1.69; 95% CI, 1.46-1.95, P < 0.05) in those with RA than in those without RA after spinal surgery. When registry data were excluded, the results suggested that the incidence of complications (OR, 2.24; 95% CI, 0.92-5.44; P = 0.08) and infections (OR, 1.76; 95% CI, 1.50-2.07; P < 0.05) was still greater for the RA group than for the non-RA group.

CONCLUSION

When undergoing spinal surgery, patients with RA have a greater risk of operative complications and infection. Surgeons should be aware of these risks and appropriately plan spinal operation for patients with RA to reduce the risk of complications.

Surgical Management of the Lumbar Spine in Rheumatoid Arthritis

STUDY DESIGN

Narrative review.

OBJECTIVE

To provide an overview on the diagnosis and surgical management of rheumatoid involvement of the lumbar spine. Rheumatoid arthritis (RA) is a chronic inflammatory disease of synovial joints, most commonly appendicular followed by axial. Although cervical spine involvement of RA is well documented, data on lumbar spine involvement and surgical management remains limited.

METHODS

Using PubMed, studies published prior to November 2018 with the keywords "RA, etiology"; "RA, spine management"; "RA, surgical management"; "RA, treatment"; "RA, DMARDs"; "RA, lumbar spine"; "RA, spine surgical outcomes"; "RA, imaging" were evaluated.

RESULTS

The narrative review addresses the epidemiology, manifestations, imaging, surgical complications, and operative and nonoperative management of RA involvement of the lumbar spine.

CONCLUSIONS

Rheumatoid involvement of the lumbar spine can present with lower back pain, neurogenic claudication, radiculopathy, spinal deformity, and instability. Patients with RA have significantly higher rates of vertebral fractures and complications following surgical intervention. However, in the setting of instability and spinal deformity, thoughtful surgical planning in conjunction with optimal medical management is recommended.

A novel dynamic fixation system with biodegradable components on lumbar fusion between articular processes in a canine model

The objective of this study was to design a novel dynamic fixation system with biodegradable components, apply it for lumbar fusion between articular processes and compare the fusion results and biomechanical changes to those of conventional rigid fixation. The novel dynamic fixation system was designed using a finite element model, stress distributions were compared and 24 mongrel dogs were randomly assigned to two groups and subjected to either posterior lumbar fusion surgery with a novel dynamic fixation system or titanium rods at the L5-L6 segments. Lumbar spines were assessed in both groups to detect radiographic, manual palpation and biomechanical changes. Histological examination was performed on organs and surrounding tissues. In the novel dynamic fixation system, stress was mainly distributed on the meshing teeth of the magnesium alloy spacer. The magnesium alloy components maintained their initial shape 8 weeks after the operation, but the meshing teeth were almost completely degraded at 16 weeks. The novel dynamic fixation system revealed an increased lateral bending range of motion at 8 weeks; however, both groups showed similar radiographic grades, fusion stiffness, manual palpation and histological results. The novel dynamic fixation system design is suitable, and its degradation in vivo is safe. The novel dynamic fixation system can be applied for posterior lumbar fusion between articular processes and complete the fusion like titanium rods.