Application of titanium and polyetheretherketone cages in the treatment of pyogenic spondylodiscitis

Use of Patient-Specific Interbody Cages Through a Minimally Invasive Lateral Approach for Unstable Lumbar Spondylodiskitis

BACKGROUND AND OBJECTIVES

Patients with diskitis/osteomyelitis who do not respond to medical treatment or develop spinal instability/deformity may warrant surgical intervention. Irregular bony destruction due to the infection can pose a challenge for spinal reconstruction. The authors report a lateral approach using patient-specific interbody cages combined with posterior or lateral instrumentation to achieve spinal reconstruction for spinal instability/deformity from spondylodiskitis.

METHODS

This is a retrospective review of 4 cases undergoing debridement, lateral lumbar interbody fusion using patient-specific interbody cages, and supplemental lateral or posterior instrumentation for spinal instability/deformity after spondylodiskitis. The surgical technique is reported, as are the clinical and imaging outcomes.

RESULTS

Four male patients with a mean age of 69 years comprised this study. One had lateral lumbar interbody fusion at L2/3 and 3 at L4/5. The mean hospital stay was 5.8 days. The mean follow-up was 8.5 months (range 6-12 months). There were no approach-related neurological injuries or complications. The mean visual analog scale back pain scores improved from 9.5 to 1.5, and the mean Oswestry disability index improved from 68.5 to 23 at the end of the follow-up. The mean lumbar lordosis increased from 18° to 51°. The segmental angle increased from 6.5° to 18°. The coronal shift was 2.8 cm preoperatively and 0.9 cm postoperatively. The coronal Cobb angle reduced from 8.8° preoperatively to 2.8° postoperatively. On postoperative computed tomography, all patients had interval development of bridging bone across the surgical level through or around the cage. None of them developed cage migration or subsidence.

CONCLUSION

Patients with irregular bony destruction due to diskitis/osteomyelitis may benefit from patient-specific cages for spinal reconstruction to address spinal instability and deformity.

Spondylodiscitis instrumented fusion, a prospective case series on a standardized neurosurgical protocol with long term follow up

PURPOSE

To investigate the fusion construct properties, construct length, intervertebral prosthesis (IVP) selection, bone grafting methods, complications management, and follow-up outcomes of spondylodiscitis fusion.

METHOD

This case series was conducted in Al-Zahra University referral hospital from March 2016 to November 2021. All the surgery-eligible patients were enrolled. Those who did not participate or failed the neurosurgical intervention were excluded. A unified neurosurgical protocol was defined. After operation and follow-up, all variables were documented. IBM SPSS v.26 was used for data analysis. P-value ≤ 0.05 was considered significant.

RESULT

Ninety-two patients were reviewed in the final analysis with 65.2 % males. The mean age was 55.07 ± 14.22 years old. The most frequent level of pathology and surgery was the lumbar spine (48.9 %). Short and long constructs were almost equally used (57.6 and 42.4 %, respectively). Bone graft mixture was the dominant IVP (75 %). The most frequent persistent postoperative symptom was back pain (55.4 %), while the neurological deficits resolution rate was 76.7 %. The fusion rate was 92.3 %. Proximal junctional kyphosis incidence was 16.3 % and had a significant association with on-admission neurological symptoms, thoracic and thoracolumbar junction involvements (p < 0.05). Follow-up Oswestry disability index scores showed 44.6 % of the patients had mild or no functional disabilities. Advanced age, On-admission deficits, comorbidities, titanium cages, and poor fusion status were associated with poor functional outcomes and higher mortality rates (P < 0.05).

CONCLUSION

The introduced neurosurgical protocol could effectively achieve acceptable SD treatment, spine stabilization, and fusion with low long-term surgical complications. Autologous bone graft mixture in comparison to titanium cages showed a higher fusion rate with a lower mortality rate. Patients with older age, neurological symptoms, and comorbidities are expected to experience less favorable clinical outcomes.

Comparison of Long-term Follow-Up of n-HA PA66 Cage and PEEK Cage of Lumbar Interbody Fusion in Multi-level Degenerative Lumbar Diseases: A Stepwise Propensity Score Matching Analysis

OBJECTIVE

Previous studies have confirmed that the nanohydroxyapatite/polyamide-66 (n-HA/PA66) cage is an ideal alternative material for degenerative lumbar disease (DLD) comparable to the polyether ether ketone (PEEK) cage due to its similar radiographic fusion, subsidence rate, and clinical results. However, these studies were restricted to one-level surgery. The aim of this study was to analyze the long-term clinical and radiologic outcomes between n-HA PA66 cage and PEEK cage for patients with multi-level degenerative lumbar diseases (DLDs).

METHODS

We retrospectively reviewed all patients who underwent multi-level transforaminal lumbar interbody fusion (TLIF) from June 2010 to December 2016 with a minimum 6-year follow-up. Matched-pair analysis was performed using a 1-to-1 closest neighbor approach to match patients who received an n-HA PA66 cage with those who received a PEEK cage. Clinical outcomes and radiographic evaluations were compared between the two groups. The independent student's t-test and χ2 -test were applied to compare the differences between groups.

RESULTS

At the end of the propensity score matching (PSM) analysis, 48 patients from n-HA/PA66 group were matched to 48 patients in the PEEK group. No significant difference was observed in cage subsidence and bony fusion except for adjacent segment degeneration (ASD). The occurrence of ASD was 14.58% (7/48) in the n-HA/PA 66 group, which was significantly less than that in the PEEK group (33.33% [16/48]) (p = 0.031). Although the intervertebral space height (IH), segmental angle (SA) and lumbar lordosis (LL) significantly increased after surgery in both groups, there was no significant difference at any time point after surgery (p > 0.05). The visual analogue scale (VAS) and Oswestry disability index (ODI) scores significantly improved in both groups at 3m postoperative, 1y postoperative and at final follow-up. However, there were no significant differences in the VAS and ODI score at any time point (p > 0.05). The total complications and re-admission rate were not different between the two groups.

CONCLUSION

Overall, our data suggest that the outcomes of n-HA/PA66 cage group are comparable to those of the PEEK cage group, with a similar high fusion rate and low cage subsidence rate as PEEK cages, except its lower rate of ASD occurrence.

Influence of instrumentation type on outcomes after surgical management of spondylodiscitis: a systematic review and meta-analysis

OBJECTIVE

Spondylodiscitis refers to infection of the intervertebral disk and neighboring structures. Outcomes based on instrumentation type are not well reported in the literature, but are important in establishing guidelines for surgical management of spondylodiscitis. This study aims to clarify the effect of instrumentation material selection on clinical and radiographic outcomes in patients with spondylodiscitis.

METHODS

Studies that evaluated the use of polyetheretherketone (PEEK), titanium, allograft, and/or autologous bone grafts for spondylodiscitis were identified in the literature. Radiographic and clinical data were analyzed using a meta-analysis of proportions, with estimated risk and confidence intervals reported for our primary study outcomes.

RESULTS

Thirty-two retrospective studies totaling 1088 patients undergoing surgical management of spondylodiscitis with PEEK, TTN, allograft, and autologous bone graft instrumentation were included. There were no differences in fusion rates (p-interaction = 0.55) with rates of fusion of 93.4% with TTN, 98.6% with allograft, 84.2% with autologous bone graft, and 93.9% with PEEK. There were no differences in screw loosening (p-interaction = 0.52) with rates of 0.33% with TTN, 0% with allograft, 1.3% with autologous bone graft, and 8.2% with PEEK. There were no differences in reoperation (p-interaction = 0.59) with rates of 2.64% with TTN, 0% with allograft, 1.69% with autologous bone graft, and 3.3% with PEEK.

CONCLUSIONS

This meta-analysis demonstrates that the choice of instrumentation type in the surgical management of spondylodiscitis resulted in no significant differences in rate of radiographic fusion, screw loosening, or reoperation. Future comparative studies to optimize guidelines for the management of spondylodiscitis are needed.

Surgical strategies for spinal infections: A narrative review

The successful operative management of spinal infections necessitates a thoughtful approach. Ideal treatment combines the universal goals of any spine operation, which are decompression of the neural elements and stabilization of instability, with source control and eradication of infection. Techniques to treat infection have evolved independently and alongside advances in implant technology and surgical techniques. This review will seek to outline current thinking on approaches to both primary and secondary spinal infections.

Comparison between Three-Dimensional Printed Titanium and PEEK Cages for Cervical and Lumbar Interbody Fusion: A Prospective Controlled Trial

OBJECTIVES

The three-dimensional printing titanium (3DPT) cage with excellent biomechanical properties and osseointegration capabilities has been initially used in spinal fusion, while the polyetheretherketone (PEEK) cage, a bioinert material device, has been a widely used for decades with relatively excellent clinical outcomes. This study was performed to investigate the early radiographic and clinical outcomes of 3DPT cage versus PEEK cage in patients undergoing anterior cervical discectomy and fusion (ACDF) and transforaminal lumbar interbody fusion (TLIF).

METHODS

This prospective controlled trial, from December 2019 to June 2022, included patients undergoing ACDF and TLIF with 3DPT cages and compared them to patients using PEEK cages for treating spinal degenerative disorders. The outcome measures included radiographic parameters (intervertebral height [IH], subsidence, fusion status, and bone-cage interface contact) and clinical outcomes (Japanese Orthopaedic Association [JOA], Neck Disability Index [NDI], Oswestry Disability Index [ODI], Short Form 12-Item Survey [SF-12], Visual Analog Scale [VAS], and Odom's criteria). Student's independent samples t test and Pearson's chi-square test were used to compare the outcome measures between the two groups before surgery and at 1 week, 3 and 6 months after surgery.

RESULTS

For the patients undergoing ACDF, the 3DPT (18 patients/[26 segments]) and PEEK groups (18 patients/[26 segments]) had similar fusion rates at 3 months and 6 months follow-up (3 months: 96.2% vs. 83.3%, p = 0.182; 6 months: 100% vs. 91.7%, p = 0.225). The subsidence in the 3DPT group was significantly lower than that in the PEEK group (3 months: 0.4 ± 0.2 mm vs. 0.9 ± 0.7 mm p = 0.004; 6 months: 0.7 ± 0.3 mm vs. 1.5 ± 0.8 mm, p < 0.001). 3DPT and PEEK cage all achieved sufficient contact with the cervical endplates. For the patients undergoing TLIF, the 3DPT (20 patients/[26 segments]) and PEEK groups (20 patients/[24 segments]) had no statistical difference in fusion rate (3 months: 84.6% vs. 58.3%, p = 0.059; 6 months: 92.3% vs. 75%, p = 0.132). The subsidence was lower than that in the PEEK group without significantly difference (3 months: 0.9 ± 0.7 mm vs.1.2 ± 0.9 mm p = 0.136; 6 months: 1.6 ± 1.0 mm vs. 2.0 ± 1.0 mm, p = 0.200). At the 3-month follow-up, the bone-cage interface contact of the 3DPT cage was significantly better than that of the PEEK cage (poor contact: 15.4% vs. 75%, p < 0.001). The values of UAR were higher in the 3DPT group than in the PEEK group during the follow-up in cervical and lumbar fusion, there were more statistical differences in lumbar fusion. There were no significant differences in the clinical assessment between 3DPT or PEEK cage in spinal fusion.

CONCLUSION

The 3DPT cage and PEEK cage can achieve excellent clinical outcomes in cervical and lumbar fusion. The 3DPT cage has advantage in fusion quality, subsidence severity, and bone-cage interface contact than PEEK cage.

[Spondylodiscitis]

Spondylodiscitis is a severe infectious disease of the spine that affects the intervertebral discs and adjacent vertebrae. It can lead to nonspecific pain, limited mobility, and destruction of spinal structures. Various pathogens, such as bacteria, fungi, or parasites, can trigger the disease. An early diagnosis and targeted treatment are crucial to reduce the risk of serious complications. Magnetic resonance imaging (MRI) with contrast agent and blood tests are essential for the diagnosis and assessing the course of the disease. The treatment includes conservative and surgical approaches. Conservative treatment consists of a minimum 6‑week antibiotic course and immobilization of the affected area. Surgical interventions, along with several weeks of antibiotic therapy, are indicated for instabilities or complications in order to eliminate the infection focus and to restore spinal stability.

Cervical spine spondylodiscitis: Review of literature on current treatment strategies

Infections of the spine are an ever-increasing health concern requiring an often complex and prolonged treatment that can lead to significant morbidity. Of particular interest is the cervical spine where there is an increase rate of post-infectious deformity, secondary neurological deficits and substantially higher rates of associated morbidity and mortality than the thoracic or lumbar spine. In this review, we explore the diagnosis and treatment of spondylodiscitis with particular focus on the cervical spine.

Safety and Efficacy of Polyetheretherketone (PEEK) Cages and Cadaveric Allografts in Transforaminal Lumbar Interbody Fusion (TLIF) for Treating Lumbar Pyogenic Spondylodiscitis

Purpose

There have been many studies in the operative management of pyogenic spondylodiscitis with foreign materials. However, it still remains an issue of debate on whether the allografts may be used in pyogenic spondylodiscitis. This study sought to evaluate the safety and effectiveness of PEEK cages and the cadaveric allograft in transforaminal lumbar interbody fusion (TLIF) for treating lumbar pyogenic spondylodiscitis.

Methods

From January 2012 to December 2019, 56 patients underwent surgery for lumbar pyogenic spondylodiscitis. The posterior debridement of all patients and their fusion with allografts, local bone grafts, and bone chip cages were performed before posterior pedicle screw fusion. An assessment of the residual pain, the grade of neurological injury, and the resolution of infection was conducted on 39 patients. The clinical outcome was evaluated using a visual analog scale (VAS) and the Oswestry Disability Index (ODI), and neurological outcomes were appraised based on Frankel grades. The radiological outcomes were evaluated via focal lordosis, lumbar lordosis, and the state of the fusion.

Results

Staphylococcus aureus and Staphylococcus epidermidis were the most common causative organisms. The mean preoperative focal lordosis was -1.2° (-11.4° to 5.7°), and the mean postoperative focal lordosis increased to 10.3° (4.3°-17.2°). At the final follow-up, there were five cases with subsidence of the cage, no case of recurrence, and no case with cage and screw loosening or migration. The mean preoperative VAS and ODI scores were 8.9 and 74.6%, respectively, and improvements in VAS and ODI were 6.6 ± 2.2 and 50.4 ± 21.3%, respectively. The Frankel grade D was found in 10 patients and grade C in 7. Following the final follow-up, only one patient improved from Frankel grade C to grade D while the others recovered completely.

Conclusion

The PEEK cage and cadaveric allograft combined with local bone grafts is a safe and effective choice for intervertebral fusion and restoring sagittal alignment without increased incidence of relapse for treating lumbar pyogenic spondylodiscitis.

Mortality, complication risks, and clinical outcomes after surgical treatment of spinal epidural abscess: a comparative analysis of patients aged 18-64 years, 65-79 years, and ≥ 80 years, with a 3-year follow-up

Spinal epidural abscess (SEA) with pyogenic vertebral osteomyelitis (PVO) is a rare illness with a steadily increasing incidence. However, comparative analyses of young and older patients with SEA are lacking. We aimed to compare the clinical course of patients aged 18-64 years, 65-79 years, and ≥ 80 years undergoing surgery for SEA. Clinical and imaging data were retrospectively collected from the institutional database between September 2005 and December 2021. Ninety-nine patients aged 18-64 years, 45 patients aged 65-79 years, and 32 patients ≥ 80 years were enrolled. Patients ≥ 80 years presented with a poorer baseline history (9.2 ± 2.4), as indicated by the CCI, than their younger counterparts (18-74 years: 4.8 ± 1.6;6.5 ± 2.5; p < 0.001). Patients aged 65-79 years and 80 years had a significantly longer length of stay. In-hospital mortality was significantly higher in those aged ≥ 80 years compared to their younger counterparts (≥ 80 years, n = 3, 9.4% vs. 18-64 years, n = 0, 0.0%; 65-79 years, n = 0, 0.0%; p < 0.001), while no differences in 90-day mortality or 30-day readmission were observed. After surgery, a significant decrease in C-reactive protein levels and leukocytes and amelioration of motor scores were observed in all the groups. Of note, older age (> 65 years), presence of comorbidities, and poor preoperative neurological condition were significant predictors of mortality. Surgical management led to significant improvements in laboratory and clinical parameters in all age groups. However, older patients are prone to multiple risks, requiring meticulous evaluation before surgery. Nevertheless, the risk profile of younger patients should not be underestimated. The study has the limitations of a retrospective design and small sample size. Larger randomized studies are warranted to establish the guidelines for the optimal management of patients from every age group and to identify the patients who can benefit from solely conservative management.

Surgical Treatment Strategies for Pyogenic Spondylodiscitis of the Thoracolumbar Spine

BACKGROUND

Despite advances, the morbidity and mortality rates of patients with spondylodiscitis remains high, with an increasing incidence worldwide. Although conservative therapy has progressed, several cases require surgical intervention. However, the indication and opportunities for surgical treatment are still disputable.

METHODS

In a joint consensus, the members of the 'Spondylodiscitis' working group of the Spine Section of the German Society for Orthopaedics and Trauma Surgery considered current literature, particularly the newly published S2k guideline of the AWMF, and examined the surgical indications and treatment strategies for thoracolumbar spondylodiscitis.

RESULTS

Surgical intervention for spondylodiscitis is only required in a small percentage of patients. In studies comparing conservative and surgical therapies, most patients benefitted from surgery, regardless of the surgical technique selected. Presently, the standard procedure is a combined dorsoventral approach, in which a monolateral attempt should always be made. The choice of material (PEEK, titanium) for ventral support does not influence the clinical result.

A Systematic Review and Meta-Analysis of Silicon Nitride and Biomaterial Modulus as it Relates to Subsidence Risk in Spinal Fusion Surgery

Introduction

For decades, researchers and surgeons have sought to determine the optimal biomaterial for spinal fusion implants. Successful fusion is associated with improved quality of life while failures are often associated with costly and complex revisions. One common failure is subsidence. Biomaterials with higher modulus are thought to be related to subsidence risk but this has not been thoroughly investigated. The aim of this systematic review and meta-analysis is to assess silicon nitride and biomaterial modulus as they relate to subsidence risk in spinal fusions.

Methods

A systematic review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Databases searched included PubMed-Medline, Google Scholar, Embase, EBSCO, and Cochrane Library. Study quality was assessed according to the Newcastle-Ottawa Scale. A network meta-analysis was chosen, allowing for direct and indirect comparisons for multiple treatments using a Bayesian hierarchical framework with Markov chain Monte Carlo methods. Outcomes were reported as odds ratios with 95% confidence intervals. Heterogeneity between studies was evaluated using the I² test. A pairwise meta-analysis was also produced to compare the results of network analysis for consistency. Publication bias was assessed using a funnel plot, Egger test, and Begg test. All analyses were conducted using R (Project for Statistical Computing, ver. 4.0.4).

Results

The initial search yielded a total of 821 articles. After removal of duplicates and screening based on inclusion and exclusion criteria, 64 articles were available for review and 13 were selected for meta-analysis. Biomaterial implant types in the final studies included: silicon nitride (Si₃N₄), polyetheretherketone (PEEK), titanium (Ti), and two composites, nano-hydroxyapatite/polyamide 66 (n-HA/PA66) and a carbon fiber reinforced polymer (CFRP). A total of 1,192 patients were included in this analysis – 419 with titanium implants, 460 with PEEK, 96 with Si₃N₄, 332 with n-HA/PA66, and 35 with CFRP. Titanium had the highest rate of subsidence compared to other biomaterials. Pairwise analysis was consistent with these results. Both the Egger test (p = 0.28) and Begg test (p = 0.37) were found to be non-significant for publication bias.

Conclusions

Spinal fusion implants derived from Si₃N₄, compared to PEEK and titanium, do not appear to be correlated with increased subsidence risk.

Surgical Management of Spinal Epidural Abscess in Elderly Patients: A Comparative Analysis Between Patients 65-79 Years and ≥80 Years with 3-Year Follow-Up

BACKGROUND

Recently, the incidence of pyogenic vertebral osteomyelitis with spinal epidural abscess (SEA) has increased. However, the most appropriate surgical management remains debatable, especially for older patients. This study aimed to compare the clinical course in older patients aged between 65 and 79 years and those 80 years or older undergoing surgery for SEA.

METHODS

Data on patient demographics, surgical characteristics, complications, hospital clinical course, and 90-day mortality of patients diagnosed with pyogenic vertebral osteomyelitis and SEA between September 2005 and December 2021 were collected. Comorbidities were assessed using the age-adjusted Charlson comorbidity index.

RESULTS

We enrolled 45 patients aged 65-79 years and 32 patients ≥80 years. Patients ≥80 years had significantly higher rates of Charlson comorbidity index (9.2 ± 2.4) than younger patients (6.5 ± 2.5; P < 0.001). Arterial hypertension, renal failure, and dementia were significantly more prevalent in octogenarians (P < 0.05). Patients aged ≥80 years had a significantly longer length of hospitalization, while the intensive care unit stay was similar between groups. In-hospital mortality was significantly greater in those ≥80 years (n = 3, 9.4% vs. n = 0, 0.0%; P = 0.029), whereas no differences in 90-day mortality or 30-day readmission were observed. In the second-stage analysis, significant improvements in blood infection parameters and neurologic status were detected in both groups. Of adverse events, pneumonia occurred significantly more frequently in patients aged ≥80 years.

CONCLUSIONS

Surgical management leads to significant improvements in both laboratory and clinical parameters in older patients. Nevertheless, a personalized medical approach is mandatory in frail patients, especially octogenarians. A clear discussion regarding the potential risk is unambiguously recommended.

Biodegradable interbody cages for lumbar spine fusion: Current concepts and future directions

Lumbar fusion often remains the last treatment option for various acute and chronic spinal conditions, including infectious and degenerative diseases. Placement of a cage in the intervertebral space has become a routine clinical treatment for spinal fusion surgery to provide sufficient biomechanical stability, which is required to achieve bony ingrowth of the implant. Routinely used cages for clinical application are made of titanium (Ti) or polyetheretherketone (PEEK). Ti has been used since the 1980s; however, its shortcomings, such as impaired radiographical opacity and higher elastic modulus compared to bone, have led to the development of PEEK cages, which are associated with reduced stress shielding as well as no radiographical artefacts. Since PEEK is bioinert, its osteointegration capacity is limited, which in turn enhances fibrotic tissue formation and peri-implant infections. To address shortcomings of both of these biomaterials, interdisciplinary teams have developed biodegradable cages. Rooted in promising preclinical large animal studies, a hollow cylindrical cage (Hydrosorb™) made of 70:30 poly-l-lactide-co-d, l-lactide acid (PLDLLA) was clinically studied. However, reduced bony integration and unfavourable long-term clinical outcomes prohibited its routine clinical application. More recently, scaffold-guided bone regeneration (SGBR) with application of highly porous biodegradable constructs is emerging. Advancements in additive manufacturing technology now allow the cage designs that match requirements, such as stiffness of surrounding tissues, while providing long-term biomechanical stability. A favourable clinical outcome has been observed in the treatment of various bone defects, particularly for 3D-printed composite scaffolds made of medical-grade polycaprolactone (mPCL) in combination with a ceramic filler material. Therefore, advanced cage design made of mPCL and ceramic may also carry initial high spinal forces up to the time of bony fusion and subsequently resorb without clinical side effects. Furthermore, surface modification of implants is an effective approach to simultaneously reduce microbial infection and improve tissue integration. We present a design concept for a scaffold surface which result in osteoconductive and antimicrobial properties that have the potential to achieve higher rates of fusion and less clinical complications. In this review, we explore the preclinical and clinical studies which used bioresorbable cages. Furthermore, we critically discuss the need for a cutting-edge research program that includes comprehensive preclinical in vitro and in vivo studies to enable successful translation from bench to bedside. We develop such a conceptual framework by examining the state-of-the-art literature and posing the questions that will guide this field in the coming years.

Decompression only versus fusion in octogenarians with spinal epidural abscesses: early complications, clinical and radiological outcome with 2-year follow-up

Despite increased life expectancy due to health care quality improvements globally, pyogenic vertebral osteomyelitis (PVO) treatment with a spinal epidural abscess (SEA) remains challenging in patients older than 80 years. We aimed to assess octogenarians for PVO prevalence with SEA and compare after-surgery clinical outcomes of decompression and decompression and instrumentation. A retrospective review of electronic medical records at a single institution was conducted between September 2005 and December 2020. Patient demographics, surgical characteristics, complications, hospital course, and 90-day mortality were collected. Comorbidities were assessed using the age-adjusted Charlson comorbidity index (CCI). Over 16 years, 35 patients aged ≥80 years with PVO and SEA were identified. Eighteen patients underwent surgical decompression (“decompression group”), and 17 underwent surgical decompression with instrumentation (“instrumentation group”). Both groups had a CCI >6 (mean±SD, 8.9±2.1 vs. 9.6±2.7, respectively; p=0.065). Instrumentation group patients had a significantly longer hospital stay but no ICU stay. In-hospital and 90-days mortality rates were similar in both groups. The mean follow-up was 26.6±12.4 months. No further surgeries were performed. Infection levels and neurological status were improved in both groups at discharge. At the second-stage analysis, significant improvements in the blood infection parameters and the neurological status were detected in the decompression group. Octogenarians with PVO and SEA have a high adverse events risk after surgical procedures. Surgical decompression might contribute to earlier clinical recovery in older patients. Thus, the surgical approach should be discussed with patients and their relatives and be carefully weighed.

PMMA-Cement-PLIF Is Safe and Effective as a Single-Stage Posterior Procedure in Treating Pyogenic Erosive Lumbar Spondylodiscitis—A Single-Center Retrospective Study of 73 Cases

Background: Surgical treatment for erosive pyogenic spondylodiscitis of the lumbar spine is challenging as, following debridement of the intervertebral and bony abscess, a large and irregular defect is created. Sufficient defect reconstruction with conventional implants using a posterior approach is often impossible. Therefore, we developed the “Cement-PLIF”, a single-stage posterior lumbar procedure, combining posterior lumbar interbody fusion (PLIF) with defect-filling using antibiotic-loaded polymethylmethacrylate (PMMA). This study first describes and evaluates the procedure’s efficacy, safety, and infection eradication rate. Radiological implant stability, bone-regeneration, sagittal profile reconstruction, procedure-related complications, and pre-existing comorbidities were further analyzed. Methods: A retrospective cohort study analyzing 73 consecutive patients with a minimum of a one-year follow-up from 2000–2017. Patient-reported pain levels and improvement in infectious serological parameters evaluated the clinical outcome. Sagittal profile reconstruction, anterior bone-regeneration, and posterior fusion were analyzed in a.p. and lateral radiographs. A Kaplan–Meier analysis was used to determine the impact of pre-existing comorbidities on mortality. Pre-existing comorbidities were quantified using the Charlson-Comorbidity Index (CCI). Results: Mean follow-up was 3.3 (range: 1–16; ±3.2) years. There was no evidence of infection persistence in all patients at the one-year follow-up. One patient underwent revision surgery for early local infection recurrence (1.4%). Five (6.9%) patients required an early secondary intervention at the same level due to minor complications. Radiological follow-up revealed implant stability in 70/73 (95.9%) cases. Successful sagittal reconstruction was demonstrated in all patients (p < 0.001). There was a significant correlation between Kaplan–Meier survival and the number of pre-existing comorbidities (24-months-survival: CCI ≤ 3: 100%; CCI ≥ 3: 84.6%; p = 0.005). Conclusions: The Cement-PLIF procedure for pyogenic erosive spondylodiscitis is an effective and safe treatment as evaluated by infection elimination, clinical outcome, restoration, and maintenance of stability and sagittal alignment.

Single-stage debridement via autogenous iliac bone graft through the OLIF corridor and lateral fixation in treating spontaneous single-level lumbar pyogenic spondylodiscitis

BACKGROUND

The aim of the present study was to investigate the efficacy and safety of mini-open oblique debridement and lumbar interbody fusion combined with lateral screw fixation for treating single-level pyogenic spondylodiscitis.

METHODS

Twelve patients with single-level lumbar pyogenic spondylodiscitis underwent OLIF combined with lateral screw fixation were analyzed. Patients underwent follow-up for 12 to 24 months. The clinical characteristics, etiological examinations, operative time, intraoperative blood loss, Oswestry Disability Index (ODI), visual analog scale score (VAS), postoperative complications, and the bony fusion rate were recorded.

RESULTS

The mean follow-up period of time was 14.8 months. The average operative time and intra-operative blood loss were 129.0 ± 19.76 min and 309.2 ± 92.96 mL, respectively. No severe intra-operative complications were observed during surgery, except in 1 case that develops abdominal pain and distension after surgery, 2 cases that develop left-sided transient thigh pain/numbness and 8 cases that complains of donor site (iliac crest) pain. All of these symptoms disappeared 8 weeks after surgery. Tissue sample cultures were obtained from all patients intraoperatively and four (33.3%) were positive, including 2 with Staphylococcus aureus, 1 with Staphylococcus epidermidis, and 1 with Escherichia coli. During an average of 22.5 ± 2.1 days (range, 14-29 days) after surgery, WBC, CPR, and ESR levels in all patients had returned to normal. All patients were pain free with no recurring infection. Solid bony fusions were observed in all cases within 6 months, including 10 with I grade fusion, 2 with II grade fusion according to the classification suggested by Burkus et al. No fixation failure was observed during follow up and solid bony fusions were observed in all 12 patients at finally follow-up. A significant postoperative increase was also observed in the mean segmental height and lordosis (P < 0.05), followed by a slight decrease of segmental height and lordosis at final follow-up. At the final follow up, the mean VAS (1.5 ± 0.6) and ODI (18.9 ± 7.6) were significantly lower than VAS (8.4 ± 2.7) and ODI (71.2 ± 16.5) before surgery (P < 0.01).

CONCLUSION

Single-stage debridement with autogenous iliac bone graft through the OLIF corridor and lateral fixation was a feasible surgical approach in our consecutive 12 cases of pyogenic spondylitis.

PEEK vs Titanium Cage for Anterior Column Reconstruction in Active Spinal Tuberculosis: A Comparative Study

Background

Posterolateral decompression and debridement in patients with TB spine led to defect in the anterior column which makes the spinal column unstable, thus making anterior column reconstruction an important step in surgical management.

Objective

Through the study, authors sought to answer the following questions: 1) What are the differences in clinical outcomes between patients with TB spine undergoing anterior column reconstruction using titanium mesh cage versus PEEK cage? 2) What are the differences in radiological outcomes between these two groups of patients?

Methods

This is a retrospective comparative study including patients with TB spine undergoing surgical management. The included subjects were divided into groups A and B depending on the implantation of PEEK or titanium mesh cage respectively for anterior column reconstruction. Outcome criteria analyzed included clinical criteria like VAS and ODI scores, radiological criteria like kyphosis correction, loss of kyphosis at follow-up, cage subsidence, and bony fusion on a 2D CT scan.

Results

The study population included 14 patients in Group A and 15 patients in Group B. Improvement in VAS and ODI scores was comparable between groups. There was no significant difference in radiological outcome measures between the two groups, however, two patients from group B showed implant-related complications needing revision. All patients showed good bony fusion at the final follow-up.

Conclusion

PEEK and titanium cages have comparable clinico-radiological outcomes for anterior column reconstruction in patients with active TB spine. Its advantages for being radiolucent and its ease of use may make it a choice of implant.

[Infections of the spine : Pyogenic spondylodiscitis and implant-associated vertebral osteomyelitis]

Pyogenic (unspecific) spondylodiscitis and implant-associated vertebral osteomyelitis (IAVO) are important diseases with the risk of neurological and septic complications. An early diagnosis is essential in which magnetic resonance imaging (MRI), histopathology and microbiological identification of the pathogen play key roles. The goals of conservative treatment in uncomplicated spondylodiscitis are antibiotic infection control and pain management. In the case of sepsis, neurological deficits, segmental instability or epidural abscesses surgical treatment of the infection with stabilization of the spine should be considered. In IAVO the formation of a mature biofilm represents the transition from acute to chronic infection. Acute infections can be treated by extensive debridement in combination with biofilm-active antibiotic treatment while retaining the implant. In chronic infections implant removal or exchange in combination with several weeks of antibiotic treatment is often necessary.

Early surgery with antibiotic medication was effective and efficient in treating pyogenic spondylodiscitis

Background

Pyogenic spondylodiscitis (PSD) is challenging to the orthopedist with regards to diagnosis and treatment. The present study was designed to assess and suggest the most indicative diagnostic method and evaluate the effect of surgery comprising of debridement, instrumentation and fusion in treating PSD.

Methods

Seventy-six patients with PSD who underwent surgical intervention were retrospectively enrolled. Their medical documents, corrections of spinal alignment and improvements in neurological function were assessed. Surgical approaches were compared in lumbar surgeries regarding the improvements in lordotic angle and neurological function.

Results

Elevated c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were found in 77.6 and 71.1% patients respectively. Infectious lesions were found at lumbar (85.5%), cervical (10.5%) and thoracic (3.9%), ascertained with contrast-enhanced MRI. For lumbar patients, surgery was performed through the anterior (26.2%), posterior (49.2%) or combined approach (24.6%), and differences in improvement of lordosis and neurological function between each approach were insignificant. The pathogen was identified in 22.4% of the patients. Postoperative antibiotic therapy was managed against the result of susceptibility test, or empirically given to patients with negative cultures. All antibiotic therapy was initiated intravenously for 4–6 weeks and orally for 6 weeks.

Conclusion

Elevated CRP and/or ESR, with focal hyper-intensity on contrast-enhanced MRI are suggestive of possible PSD. Surgical intervention comprising of debridement, short-segment instrumentation and fusion that early applied to the PSD patients followed by postoperative antibiotic therapy have demonstrated preferable outcomes, but require further study.

The translational potential of this article

This article advocates early surgery to enable prompt diagnosis and treatment of PSD, and thus guarantee favorable outcomes for patients, as is shown in our study. In addition, different surgical approaches to the lesions were compared and discussed in this manuscript, but no differences in outcome between approaches were found. This suggests that thorough debridement should be prioritized over selection of surgical approach. In summary, this article has large translational potential to be applied clinically.

Titanium (Ti) cages may be superior to polyetheretherketone (PEEK) cages in lumbar interbody fusion: a systematic review and meta-analysis of clinical and radiological outcomes of spinal interbody fusions using Ti versus PEEK cages

AIM

Interbody cages are commonly used to augment interbody fusion. Commonly used materials include titanium (Ti) and polyetheretherketone (PEEK), with their inherent differences. The aim of this study is to perform a systematic review and meta-analysis to compare between the various clinical and radiological outcomes of Ti and PEEK interbody spinal cages.

METHODS

A systematic review and meta-analysis comparing clinical and radiological outcomes between Ti and PEEK interbody cages in patients undergoing spinal fusion was performed. PubMed, Scopus, Web of Science, Embase, and Cochrane Central Register of Controlled Trials database were searched. All studies that compared the clinical and radiological outcomes of patients who underwent Ti and PEEK cages were included. Subgroup analyses was performed to differentiate between patients who had cervical and lumbar interbody fusion.

RESULTS

A total of 11 articles were identified, with a total of 743 patients. Spinal fusion rates at final follow-up did not differ between Ti and PEEK cages (OR 1.50, 95% CI 0.57-3.94, P = 0.41), although in patients undergoing lumbar fusion, Ti cages demonstrated superior fusion (OR 2.12, 95% CI 1.05-4.28, P = 0.04). In patients with non-infective etiologies, Ti cages had a higher rate of cage subsidence (RR 2.17, 95% CI 1.13-4.16, P = 0.02). Both types of cages had similar operating time, postoperative hematoma formation, neuropathic pain, segmental angle correction and postoperative clinical outcome improvement.

CONCLUSION

In non-infective lumbar spine conditions, Ti cage may be the superior option due to the higher fusion rate.

LEVEL OF EVIDENCE

III.

Bacterial adhesion characteristics on implant materials for intervertebral cages: titanium or PEEK for spinal infections?

PURPOSE

Surgical intervention with intercorporal stabilisation in spinal infections is increasingly needed. Our aim was to compare titanium and polyetheretherketon (PEEK) cages according to their adhesion characteristics of different bacteria species in vitro.

METHODS

Plates made from PEEK, polished titanium (Ti), two-surface-titanium (TiMe) (n = 2-3) and original PEEK and porous trabecular structured titanium (TiLi) interbody cages (n = 4) were inoculated in different bacterial solutions, S.aureus (MSSA, MRSA), S.epidermidis and E.coli. Growth characteristics were analysed. Biofilms and bacteria were visualised using confocal- and electron microscopy.

RESULTS

Quantitative adherence of MSSA, MRSA, S.epidermidis and E.coli to Ti, TiMe and PEEK plates were different, with polished titanium being mainly advantageous over PEEK and TiMe with significantly less counts of colony forming units (CFU) for MRSA after 56 h compared to TiMe and at 72 h compared to PEEK (p = 0.04 and p = 0.005). For MSSA, more adherent bacteria were detected on PEEK than on TiMe at 32 h (p = 0.02). For PEEK and TiLi cages, significant differences were found after 8 and 72 h for S.epidermidis (p = 0.02 and p = 0.008) and after 72 h for MSSA (p = 0.002) with higher bacterial counts on PEEK, whereas E.coli showed more CFU on TiLi than PEEK (p = 0.05). Electron microscopy demonstrated enhanced adhesion in transition areas.

CONCLUSION

For S.epidermidis, MSSA and MRSA PEEK cages showed a higher adherence in terms of CFU count, whereas for E.coli PEEK seemed to be advantageous. Electron microscopic visualisation shows that bacteria did not adhere at the titanium mesh structure, but at the border zones of polished material to rougher parts.

Skipping Pedicle Screw Insertion Into Infected Vertebra is a Risk Factor for Revision Surgery for Pyogenic Spondylitis in the Lower Thoracic and Lumbar Spine

BACKGROUND

Surgical intervention for pyogenic spondylitis is indicated when conservative treatment fails and biomechanical instability persists. Whether to insert pedicle screws into all vertebrae, including the most erosive vertebrae, or whether to skip 1 vertebra in pedicle screw insertion remains controversial.

METHODS

A single-institution retrospective cohort study was conducted in consecutive patients with pyogenic spondylitis in the lower thoracic and lumbar spine (T9-S1) between January 2008 and December 2016. The patients were treated with interbody fusion plus posterior stabilization using pedicle screws and were divided into 2 groups as follows: (1) patients in whom 1 vertebra, usually the most erosive, was skipped in pedicle screw insertion (Group Skipping) and (2) pedicle screw insertion into all vertebrae (Group All). Patients' operation data were evaluated, and clinical outcomes were compared between the 2 groups. There were no significant differences between the 2 groups in terms of age, sex, past histories, blood loss, operation time, the presence of abscesses, or operative approach.

RESULTS

The length of fixation was greater by 1 vertebral level in the Group Skipping than in the Group All, and the rate of revision surgery for pseudarthrosis was higher in the Group Skipping than in the Group All (P = .02). There was no statistically significant difference between the 2 groups in terms of the mean segmental lordotic angle or Barthel Index.

CONCLUSIONS

Skipping pedicle screw insertion for pyogenic spondylitis in posterior fixation led to an increased number of fixed vertebrae and may be a risk factor for revision surgery for pseudarthrosis.

LEVEL OF EVIDENCE

4.

CLINICAL RELEVANCE

The insertion of short pedicle screws at the infected vertebra can prevent early treatment failure and increase the biomechanical stability of construct.

Surgical revision strategies for postoperative spinal implant infections (PSII)

Over the last years the number of spine surgeries with instrumentation has grown to an indispensable column in the treatment for different pathologies of the spine. A further increase in the incidence of instrumented spinal surgery is expected throughout the next years. Although the implementation and development of new techniques offer faster and more minimal invasive procedures, shortening surgery time, reducing soft tissue injury and revision due to hardware misplacement, the incidence of postoperative spinal implant infections (PSII) remains high. PSII related complications and revision procedures pose an enormous socioeconomic burden. Therefore, standardized strategies and protocols for treatment of PSII are urgently needed. While in former times hardware exchange or hardware removal was common practise in the field of spine surgery this approach has changed over the last years. Although the evidence from clinical studies in the field of PSII is of limited evidence, critical variables for revision strategies of PSII have been identified. Further, to quickly advance in the field of PSII it is certainly important to extrapolate and learn using data regarding the management from other fields of prosthetic joint infections. This should include clinical as well as experimental work in particular in the context of the biofilm, sonication as well as microbiological concepts. Over the last years, at our institution standardized procedures for diagnostic, surgical as well as antimicrobial treatment have been developed, based on the latest recommendations in peer-reviewed literature and our own data. Here we give an overview about surgical revision strategies for PSII and discuss the key points of our standardized protocol.

Antibiotic-impregnated polymethylmethacrylate strut graft as a treatment of spinal osteomyelitis: case series and description of novel technique

OBJECTIVE

The surgical treatment of osteomyelitis and discitis of the spine often represents a challenging clinical entity for a multitude of reasons, including progression of infection despite debridement, development of spinal deformity and instability, bony destruction, and seeding of hardware. Despite advancement in spinal hardware and implantation techniques, these aforementioned challenges not uncommonly result in treatment failure, especially in instances of heavy disease burden with enough bony endplate destruction as to not allow support of a modern titanium cage implant. While antibiotic-infused polymethylmethacrylate (aPMMA) has been used in orthopedic surgery in joints of the extremities, its use has not been extensively described in the spine literature. Herein, the authors describe for the first time a series of patients treated with a novel surgical technique for the treatment of spinal osteomyelitis and discitis using aPMMA strut grafts with posterior segmental fusion.

METHODS

Over the course of 3 years, all patients with spinal osteomyelitis and discitis at a single institution were identified and included in the retrospective cohort if they were surgically treated with spinal fusion and implantation of an aPMMA strut graft at the nidus of infection. Basic demographics, surgical techniques, levels treated, complications, and return to the operating room for removal of the aPMMA strut graft and placement of a traditional cage were examined. The surgical technique consisted of performing a discectomy and/or corpectomy at the level of osteomyelitis and discitis followed by placement of aPMMA impregnated with vancomycin and/or tobramycin into the cavity. Depending on the patient's condition during follow-up and other deciding clinical and radiographic factors, the patient may return to the operating room nonurgently for removal of the PMMA spacer and implantation of a permanent cage with allograft to ultimately promote fusion.

RESULTS

Fifteen patients were identified who were treated with an aPMMA strut graft for spinal osteomyelitis and discitis. Of these, 9 patients returned to the operating room for aPMMA strut graft removal and insertion of a cage with allograft at an average of 19 weeks following the index procedure. The most common infections were methicillin-sensitive Staphylococcus aureus (n = 6) and methicillin-resistant S. aureus (n = 5). There were 13 lumbosacral infections and 1 each of cervical and thoracic infection. Eleven patients were cured of their infection, while 2 had recurrence of their infection; 2 patients were lost to follow-up. Three patients required unplanned return trips to the operating room, two of which were for wound complications, with the third being for recurrent infection.

CONCLUSIONS

In cases of severe infection with considerable bony destruction, insertion of an aPMMA strut graft is a novel technique that should be considered in order to provide strong anterior-column support while directly delivering antibiotics to the infection bed. While the active infection is being treated medically, this structural aPMMA support bridges the time it takes for the patient to be converted from a catabolic to an anabolic state, when it is ultimately safe to perform a definitive, curative fusion surgery.

Consensus on Implants in Infections After Spine Surgery

In July of 2018, the Second International Consensus Meeting (ICM) on Musculoskeletal Infection convened in Philadelphia, PA was held to discuss issues regarding infection in orthopedic patients and to provide consensus recommendations on these issues to practicing orthopedic surgeons. During this meeting, attending delegates divided into subspecialty groups to discuss topics specifics to their respective fields, which included the spine. At the spine subspecialty group meeting, delegates discussed and voted upon the recommendations for 63 questions regarding the prevention, diagnosis, and treatment of infection in spinal surgery. Of the 63 questions, 9 focused on implants questions in spine surgery, for which this article provides the recommendations, voting results, and rationales.

Application of polyetheretherketone cages through minimally invasive oblique retroperitoneal approach for the treatment of lumbar polymicrobial spondylodiscitis: A STROBE-compliant retrospective study with 7 cases

Despite the plethora of evidence in support of the use of structural osseous autograft in lumbar spondylodiscitis, attention has recently been turned to the addition of synthetic materials such as polyetheretherketone (PEEK) to restore anterior vertebral column support.From January 2015 to April 2017, 7 patients with lumbar polymicrobial spondylodiscitis were surgically treated with a minimally invasive oblique retroperitoneal approach to the infected focus. The patients underwent a standard lateral minimally invasive oblique retroperitoneal approach using direct lateral interbody fusion system. The PEEK cages were loaded with autologous bone graft. All the patients underwent posterior fixation with percutaneous pedicle screw instrumentation. Lumbar function was measured using Oswestry Disability Index, and pain was measured with visual analog scale. Fusion and subsidence were also recorded.The study included 5 female and 2 male patients. The median age was 58.9 years. The duration of follow-up was 31.8 ± 6.1 months (range: 24-47). All patients recovered from the infection without relapse within 24-month follow-up. Visual analog scale significantly declined from 7.57 ± 0.53 before surgery to 1.57 ± 0.53 at 12-month follow-up. Mean Oswestry Disability Index decreased from 72.14 ± 6.82 before surgery to 22.28 ± 2.13 after surgery. All patients had solid fusion at 2-year follow-up. Fusion occurred at 6 to 15 months (mean 9.8 months).The specific use of PEEK cages in lumbar polymicrobial spondylodiscitis suggests reliable outcome in terms of clinical and imaging outcomes in our limited cases.

Medium-term outcome of posterior surgery in the treatment of non-tuberculous bacterial spinal infection

Objective

to evaluate the outcome of posterior spinal stabilization surgery for the management of bacterial spinal infection.

Methods

21 patients with bacterial infection were managed surgically with posterior stabilization. Outcome measures included neurological status. Follow-up data collected using Spine Tango COMI questionnaires and Euro Qol EQ-5D.

Results

The mean improvement in neurological deficits was 0.91 Frankel grade. Residual symptoms of pain had no or minor effect on the work or usual activities in 52% of subjects, with 88% reported having either no or mid problems with mobility.

Conclusion

Posterior surgery can improve neurological outcome in approximately half of the patients.

Single-approach vertebral osteosynthesis in the treatment of spinal osteolysis by spondylodiscitis

OBJECTIVEBoth spontaneous and iatrogenic spondylodiscitis are becoming ever more frequent, yet there are no definite treatment guidelines. For many years the treatment protocol was conservative medical management or surgical debridement with patients immobilized or bedridden for weeks and often resulting in spinal deformity. The eventual development of spinal deformity can be difficult to treat. Over the last few years, the authors have preferred a single-approach instrumented arthrodesis when spondylolysis that evolves in deformity from somatic wedging occurs.METHODSThe authors retrospectively reviewed the clinical, radiological, and surgical records of 11 patients treated over the past 3 years for spondylodiscitis with osteosynthesis.RESULTSOverall, the authors treated 11 patients: 3 cases with tuberculous spondylodiscitis (1 dorsal, 2 lumbar); 6 cases with Staphylococcus aureus spondylodiscitis (1 cervical, 2 dorsal, 2 lumbar, 1 dorsolumbar); 1 spondylodiscitis with postsurgical lumbar deformity; and in 1 dorsolumbar case the germ was not identified. Surgical approaches were chosen according to spinal level: In 8 dorsolumbar cases a posterior osteosynthesis was achieved. In 1 cervical case an anterior approach was performed with autologous bone graft from iliac crest. In 2 thoracolumbar cases a posterolateral costotransversectomy was needed. In 1 lumbosacral case iliac somatic grafting was used. Ten patients received adequate antibiotic treatment with clinical remission, and 1 case is in initial follow-up. No complications due to instrumentation were recorded. Spinal deformity was prevented in 10 cases, whereas preexisting spinal deformity was partially corrected in 1 case. In all cases, arthrodesis achieved vertebral stability.CONCLUSIONSThis study has the limitations of a retrospective review with a limited number of patients. Instrumentation does not appear to hamper healing from infection. Moreover, spinal stabilization, which is assisted by the infectious process even in the absence of bone graft, allows early mobilization. Instrumented osteosynthesis should be preferred for spondylodiscitis with osteolysis and spinal instability because it allows early mobilization and rehabilitation whenever necessary. It prevents spinal deformity and does not hamper healing of infections.

Presentation and Outcomes After Medical and Surgical Treatment Versus Medical Treatment Alone of Spontaneous Infectious Spondylodiscitis: A Systematic Literature Review and Meta-Analysis

STUDY DESIGN

Systematic literature review.

OBJECTIVES

The aims of this study were to (1) describe the clinical features, disabilities, and incidence of neurologic deficits of pyogenic spondylodiscitis prior to treatment and (2) compare the functional outcomes between patients who underwent medical treatment alone or in combination with surgery for pyogenic spondylodiscitis.

METHODS

A systematic literature review was performed using PubMed according to PRISMA guidelines. No year restriction was put in place. Statistical analysis of pooled data, when documented in the original report (ie, number of patients with desired variable and number of patients evaluated), was conducted to determine the most common presenting symptoms, incidence of pre- and postoperative neurologic deficits, associated comorbidities, infectious pathogens, approach for surgery when performed, and duration of hospitalization. Outcomes data, including return to work status, resolution of back pain, and functional recovery were also pooled among all studies and surgery-specific studies alone. Meta-analysis of studies with subgroup analysis of pain-free outcome in surgical and medical patients was performed.

RESULTS

Fifty of 1286 studies were included, comprising 4173 patients undergoing either medical treatment alone or in combination with surgery. Back pain was the most common presenting symptom, reported in 91% of patients. Neurologic deficit was noted in 31% of patients. Staphylococcus aureus was the most commonly reported pathogen, seen in 35% of reported cases. Decompression and fusion was the most commonly reported surgical procedure, performed in 80% of the surgically treated patients. Combined anterior-posterior procedures and staged surgeries were performed in 33% and 26% of surgeries, respectively. The meta-analysis comparing visual analog scale score at follow-up was superior among patients receiving surgery over medical treatment alone (mean difference -0.61, CI -0.90 to -0.25), while meta-analysis comparing freedom from pain in patients receiving medical treatment alone versus combined medical and surgical treatment demonstrated superior pain-free outcomes among surgical series (odds ratio 5.35, CI 2.27-12.60, P < .001), but was subject to heterogeneity among studies (I ² = 56%, P = .13). Among all patients, freedom from pain was achieved in 79% of patients, and an excellent outcome was achieved in 73% of patients.

CONCLUSION

Medical management remains first-line treatment of infectious pyogenic spondylodiscitis. Surgery may be indicated for progressive pain, persistent infection on imaging, deformity or neurologic deficits. If surgery is required, reported literature shows potential for significant pain reduction, improved neurologic function and a high number of patients returning to a normal functional/work status.

Strategies for the Prevention and Treatment of Surgical Site Infection in the Lumbar Spine

Surgical site infection (SSI) following spine surgery can be devastating for both the patient and the surgeon. It leads to significant morbidity and associated health care costs, from readmissions, reoperations, and subsequent poor clinical outcomes. Complications associated with SSI following spine surgery include pseudarthrosis, neurological deterioration, sepsis, and death. Its management can be very challenging. The diagnosis of SSI involves the interpretation of combined clinical, laboratory, and occasionally radiologic findings. Most infections can be treated with an appropriate course of antibiotics and bracing if required. Surgical intervention is usually reserved for infections resistant to medical management, the need for open biopsy/culture, evolving spinal instability or deformity, and neurologic deficit or deterioration. A thorough knowledge of associated risk factors is required and patients should be stratified for risk preoperatively. The multifaceted approach of risk stratification, early diagnosis and effective treatment, is essential for successful prevention and effective treatment and crucial for a satisfactory outcome.

Clinical and Radiographic Results of a Minimally Invasive Lateral Transpsoas Approach for Treatment of Septic Spondylodiscitis of the Thoracolumbar and Lumbar Spine

BACKGROUND

The minimally invasive lateral transpsoas approach allows retroperitoneal access for discectomy and graft placement. However, the procedure has rarely been used for the treatment of septic spondylodiscitis. The purposes of this study were to evaluate the clinical and radiographic outcomes from this minimally invasive procedure for septic spondylodiscitis.

METHODS

Thirty-one consecutive patients (17 males and 14 females) were included in this study from July 2013 to January 2016. Clinical outcomes were assessed by Oswestry Disability Index, visual analog scale, modified Macnab criteria, and inflammatory parameters. Radiographic results were analyzed by studying the changes in diseased disc height, lordosis, and fusion status.

RESULTS

The Oswestry Disability Index and visual analog scale score improved by 58% and 69% at the last follow-up. The modified Macnab criteria were found to be excellent in 21 patients (68%) and good in 10 (32%). Inflammatory parameters normalized over the average 24 months follow-up. There were no major complications that might have influenced the outcomes in this cohort. A complete fusion after 12 months was achieved in 87% of patients. A mean 7.5 mm restoration in disc height and 6.4° restoration in lumbar lordosis were observed in all patients, whereas an average 4.5 mm loss in restored height resulting from graft subsidence was observed in 24 patients during the follow-up. However, graft subsidence did not influence clinical outcomes significantly.

CONCLUSIONS

A minimally invasive lateral transpsoas approach in combination with instrumentation provides a novel treatment for patients with septic spondylodiscitis without severe kyphosis and neurologic impairment.

Spondylodiscitis revisited

Spondylodiscitis may involve the vertebral bodies, intervertebral discs, paravertebral structures and spinal canal, with potentially high morbidity and mortality rates.

A rise in the susceptible population and improved diagnosis have increased the reported incidence of the disease in recent years.

Blood cultures, appropriate imaging and biopsy are essential for diagnosis and treatment.

Most patients are successfully treated by conservative means; however, some patients may require surgical treatment.

Surgical indications include doubtful diagnosis, progressive neurological deficits, progressive spinal deformity, failure to respond to treatment, and unresolved pain.

Cite this article: EFORT Open Rev 2017;2:447–461. DOI: 10.1302/2058-5241.2.160062

Titanium vs. polyetheretherketone (PEEK) interbody fusion: Meta-analysis and review of the literature

Spinal interbody fusion is a standard and accepted method for spinal fusion. Interbody fusion devices include titanium (Ti) and polyetheretherketone (PEEK) cages with distinct biomechanical properties. Titanium and PEEK cages have been evaluated in the cervical and lumbar spine, with conflicting results in bony fusion and subsidence. Using Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, we reviewed the available literature evaluating Ti and PEEK cages to assess subsidence and fusion rates. Six studies were included in the analysis, 3 of which were class IV evidence, 2 were class III, and 1 was class II. A total of 410 patients (Ti-228, PEEK-182) and 587 levels (Ti-327, PEEK-260) were studied. Pooled mean age was 50.8years in the Ti group, and 53.1years in the PEEK group. Anterior cervical discectomy was performed in 4 studies (395 levels) and transforaminal interbody fusion in 2 studies (192 levels). No statistically significant difference was found between groups with fusion (OR 1.16, 95% C.I 0.59-2.89, p=0.686, I²=49.7%) but there was a statistically significant the rate of subsidence with titanium (OR 3.59, 95% C.I 1.28-10.07, p=0.015, I²=56.9%) at last follow-up. Titanium and PEEK cages are associated with a similar rate of fusion, but there is an increased rate of subsidence with titanium cage. Future prospective randomized controlled trials are needed to further evaluate these cages using surgical and patient-reported outcomes.

Minimally invasive spine surgery in lumbar spondylodiscitis: a retrospective single-center analysis of 67 cases

BACKGROUND

Minimally invasive surgical techniques have been developed to minimize tissue damage, reduce narcotic requirements, decrease blood loss, and, therefore, potentially avoid prolonged immobilization. Thus, the purpose of the present retrospective study was to assess the safety and efficacy of a minimally invasive posterior approach with transforaminal lumbar interbody debridement and fusion plus pedicle screw fixation in lumbar spondylodiscitis in comparison to an open surgical approach. Furthermore, treatment decisions based on the patient´s preoperative condition were analyzed.

METHODS

67 patients with lumbar spondylodiscitis treated at our department were included in this retrospective analysis. The patients were categorized into two groups based on the surgical procedure: group (MIS) minimally invasive lumbar spinal fusion (n = 19); group (OPEN) open lumbar spinal fusion (n = 48). Evaluation included radiological parameters on magnetic resonance imaging (MRI), laboratory values, and clinical outcome.

RESULTS

Preoperative MRI showed higher rates of paraspinal abscess (35.5 vs. 5.6%; p = 0.016) and multilocular location in the OPEN group (20 vs. 0%, p = 0.014). Overall pain at discharge was less in the MIS group: NRS 2.4 ± 1 vs. NRS 1.6 ± 1 (p = 0.036). The duration of hospital stay was longer in the OPEN than the MIS group (19.1 ± 12 days vs. 13.7 ± 5 days, p = 0.018).

CONCLUSION

The open technique is effective in all varieties of spondylodiscitis inclusive in epidural abscess formation. MIS can be applied safely and effectively as well in selected cases, even with epidural abscess.

[Spondylodiscitis : Current strategies for diagnosis and treatment]

Spondylodiscitis is a severe infectious disease of the intervertebral discs and of the adjacent parts of the vertebral bodies, culminating in destruction of the mobile segment. It is accompanied by a mortality rate of approximately 15%. Severe courses of the disease can also lead to abscess formation and dispersal of sepsis. Malpositioning of the axis organ and deficits in neurological function up to paraplegia are also possible complications. Timely diagnostics and targeted therapy contribute to minimizing the risk of significant health disorders. This review article gives a summary of important algorithms in the diagnostics and treatment and discusses them against the background of currently available literature. According to the current state of knowledge the surgical treatment of spondylodiscitis provides many advantages and is therefore the method choice, even if a conservative approach can be successful in selected cases. The endpoints of treatment are cleansing of the infection with normalization of laboratory parameters of inflammation and the osseous fusion of the mobile segment.

Safety and efficacy of polyetheretherketone (PEEK) cages in combination with posterior pedicel screw fixation in pyogenic spinal infection

BACKGROUND

To date, there is growing consensus that PEEK material may be used for interbody fusion in spinal infections. Data supporting that claim are however restricted to a few very small clinical series. The aim of this study is to evaluate the outcome of surgical treatment of pyogenic spinal infections with PEEK cages in combination with posterior pedicel screw fixation.

METHODS

Between 2006 and 2013, a total of 211 patients suffering from spondylodiscitis underwent surgical debridement and instrumentation. There were 52 cases where PEEK cages were used. Laboratory and physical examinations were assessed at a 3-month follow-up. Last follow-up was performed with at a minimum of 12 months after surgery via a telephone interview.

RESULTS

Mean age at presentation was 67 years, with 19 (37 %) male patients and 33 (63 %) female. Distribution of the infection was lumbar in 29 (56 %%), thoracic in 3 (6 %) and cervical in 11 (21 %) cases. Nine patients (17 %) had concomitant non-contiguous spondylodiscitis. Epidural abscess was found in 17 patients (33 %); 48 (92 %%) had pain; neurological deficits were found in 20 patients (38 %). All patients in this series underwent surgical debridement with instrumentation of the spine. Postoperative intravenous antibiotics were administered for 15.4 ± 6.8 days followed by 2.9 ± 0.5 months of oral antibiotics. Complete resolution of the infection was achieved in all cases. Of the 28 patients with neurological deficits, 6 had full recovery and 10 had improved incompletely after surgery. One patient suffered from a pulmonary embolism postoperatively. There were no mortalities.

CONCLUSIONS

Use of PEEK cages for interbody fusion is feasible and safe in patients suffering from a pyogenic spinal infection.

Posterior Titanium Screw Fixation without Debridement of Infected Tissue for the Treatment of Thoracolumbar Spontaneous Pyogenic Spondylodiscitis

Study Design

Retrospective study.

Purpose

The aim of our study was to analyze the safety and effectiveness of posterior pedicle screw fixation for treatment of pyogenic spondylodiscitis (PSD) without formal debridement of the infected tissue.

Overview of Literature

Posterior titanium screw fixation without formal debridement of the infected tissue and anterior column reconstruction for the treatment of PSD is still controversial.

Methods

From March 2008 to June 2013, 18 patients with PSD underwent posterior titanium fixation with or without decompression, according to their neurological deficit. Postero-lateral fusion with allograft transplantation alone or bone graft with both the allogenic bone and the autologous bone was also performed. The outcome was assessed using the visual analogue scale (VAS) for pain and the Frankel grading system for neurological status. Normalization both of C-reactive protein (CRP) and erythrocyte sedimentation rate was adopted as criterion for discontinuation of antibiotic therapy and infection healing. Segmental instability and fusion were also analyzed.

Results

At the mean follow-up time of 30.16 months (range, 24–53 months), resolution of spinal infection was achieved in all patients. The mean CRP before surgery was 14.32±7.9 mg/dL, and at the final follow-up, the mean CRP decreased to 0.5±0.33 mg/dL (p <0.005). Follow-up computed tomography scan at 12 months after surgery revealed solid fusion in all patients. The VAS before surgery was 9.16±1.29 and at the final follow-up, it improved to 1.38±2.03, which was statistically significant (p <0.05). Eleven patients out of eighteen (61.11%) with initial neurological impairment had an average improvement of 1.27 grades at the final follow-up documented with the Frankel grading system.

Conclusions

Posterior screw fixation with titanium instrumentation was safe and effective in terms of stability and restoration of neurological impairment. Fixation also rapidly reduced back pain.

Pyogenic lumbar spondylodiscitis treated with transforaminal lumbar interbody fusion: safety and outcomes

PURPOSE

Our aim was to study the safety and outcomes of posterior instrumentation and transforaminal lumbar interbody fusion (TLIF) for treating pyogenic lumbar spondylodiscitis.

METHODS

Retrospective analysis was performed on prospectively collected data of 27 consecutive cases of lumbar pyogenic spondylodiscitis treated with posterior instrumentation and TLIF between January 2009 and December 2012. Cases were analysed for safety, radiological and clinical outcomes of transforaminal interbody fusion using bone graft ± titanium cages. Interbody metallic cages with bone graft were used in 17 cases and ten cases used only bone graft. Indications for surgical treatment were failed conservative management in 17, neurodeficit in six and significant bony destruction in four.

RESULTS

There were no cases reporting cage migration, loosening, pseudoarthrosis or recurrence of infection at a mean follow-up of 30 months. Clinical outcomes were assessed using Kirkaldy-Willis criteria, which showed 14 excellent, nine good, three fair and one poor result. Mean focal deformity improved with the use of bone graft ± interbody cages, and the deformity correction was maintained at final follow-up. Mean pre-operative focal lordosis for the graft group was 8.5° (2-16.5°), which improved to 10.9 °(3.3-16°); mean pre-operative focal lordosis in the group treated with cages was 6.7 °(0-15°), which improved to 7°(0-15°) .

CONCLUSION

TLIFs with cages in patients with pyogenic lumbar spondylodiscitis allows for acceptable clearance of infection, satisfactory deformity correction with low incidence of cage migration, loosening and infection recurrence.

Outcome of conservative and surgical treatment of pyogenic spondylodiscitis: a systematic literature review

BACKGROUND

Spondylodiscitis is a spinal infection affecting primarily the intervertebral disk and the adjacent vertebral bodies. Currently many aspects of the treatment of pyogenic spondylodiscitis are still a matter of debate.

PURPOSE

The aim of this study was to review the currently available literature systematically to determine the outcome of patients with pyogenic spondylodiscitis for conservative and surgical treatment strategies.

METHODS

A systematic electronic search of MEDLINE, EMBASE, Cochrane Collaboration, and Web of Science regarding the treatment of pyogenic spondylodiscitis was performed. Included articles were assessed on risk of bias according the Cochrane Handbook for Systematic Reviews of Interventions, and the quality of evidence and strength of recommendation was evaluated according the GRADE approach.

RESULTS

25 studies were included. Five studies had a high or moderate quality of evidence. One RCT suggest that 6 weeks of antibiotic treatment of pyogenic spondylodiscitis results in a similar outcome when compared to longer treatment duration. However, microorganism-specific studies suggest that at least 8 weeks of treatment is required for S. aureus and 8 weeks of Daptomycin for MRSA. The articles that described the outcome of surgical treatment strategies show that a large variety of surgical techniques can successfully treat spondylodiscitis. No additional long-term beneficial effect of surgical treatment could be shown in the studies comparing surgical versus antibiotic only treatment.

CONCLUSION

There is a strong level of recommendation for 6 weeks of antibiotic treatment in pyogenic spondylodiscitis although this has only been shown by one recent RCT. If surgical treatment is indicated, it has been suggested by two prospective studies with strong level of recommendation that an isolated anterior approach could result in a better clinical outcome.

A paradigm for the evaluation and management of spinal coccidioidomycosis

Background:

Coccidioidomycosis is a fungal infection that is endemic to parts of the Southwestern United States. When infection involves the spine, the treatment strategies can be challenging. We have devised a management protocol for spinal coccidioidomycosis based on a review of the literature and our experience.

Methods:

The electronic literature search of National Library of Medicine for publications from 1964 to 2014 was performed using the following keywords: Coccidioidomycosis and spine. The search yielded 24 papers. Treatment strategies were summarized into a treatment protocol.

Results:

A total of 164 cases of spinal coccidioidomycosis were identified, ranging in age from <10 to >80 years. Males (n = 131) and African-Americans (n = 79) were strikingly over-represented. Medical therapy: Once a diagnosis of spinal coccidioidomycosis is established, antifungal therapy should always be started. Antifungal therapy with amphotericin B or azoles like fluconazole. Medical therapy needs to be continued for many years and sometimes indefinitely to reduce disease recurrence or progression. Surgical management is indicated in cases with mechanical instability, neurologic deficit, medically intractable pain, or progression of infection despite antifungal therapy.

Conclusions:

This work provides a working protocol involving assessment and reassessment for the management of spinal coccidioidomycosis. Medical management with antifungal agents in some cases can provide satisfactory disease control. However, in patients with mechanical instability, neurologic deficit, medically intractable pain or disease progression disease control may only be achieved with surgical debridement and stabilization.

Distribution of HIV-1 in the genomes of AIDS patients

The localization of HIV-1 proviruses in compositional DNA fractions from 27 AIDS patients during the chronic phase of the disease with depletion of CD4+ and different levels of viremia showed the following. (1) At low viremia, proviruses are predominantly localized in the GC-richest isochores, which are characterized by an open chromatin structure; this result mimics findings on HIV-1 integration in early infected cells in culture. (2) At higher viremia, an increased distribution of proviruses in GC-poor isochores (which match the GC poorness of HIV-1) was found; this suggests a selection of cells in which the 'isopycnic' localization leads to a higher expression of proviruses and, in turn, to higher viremia. (3) At the highest viremia, integrations in GC-rich isochores are often predominant again, but generally not at the same level as in (1); this may be the consequence of new integrations from the extremely abundant RNA copies.