The Surgical Treatment of Pyogenic Spondylodiscitis using Carbon-Fiber-Reinforced Polyether Ether Ketone Implants: Personal Experience of a Series of 81 Consecutive Patients

Cervical Pyogenic Spondylitis: A Comprehensive Review of Diagnosis and Treatment Strategy

Cervical pyogenic spondylitis (CPS) is a rare but serious spinal infection with a high risk of neurological compromise due to the cervical spine's narrow canal and proximity to critical neurovascular structures. Early diagnosis relies on a high index of suspicion supported by MRI, inflammatory markers, blood cultures, and tissue biopsy. Empirical intravenous antibiotics remain the cornerstone of initial treatment, followed by pathogen-specific therapy. Surgical intervention is indicated in cases of neurological deterioration, spinal instability, or failure of conservative management. Anterior approaches, including anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF), are widely used, with anterior plating providing biomechanical advantages in select cases. Posterior or combined anterior-posterior approaches are recommended in multilevel disease, deformity, or posterior element involvement. Graft selection-typically autograft or titanium/PEEK cages-must consider infection severity and biomechanical demands. Challenges in CPS management include optimal debridement extent, graft choice in infected environments, the standardization of antibiotic protocols, and the prevention of recurrence. This narrative review synthesizes the cervical-spine-specific literature on diagnosis, treatment strategies, surgical techniques, and postoperative care and proposes the following practical clinical guidance: (1) early MRI for timely diagnosis, (2) prompt surgical intervention in patients with neurological deficits or mechanical instability, and (3) individualized graft selection based on infection severity and bone quality.

Management of Pyogenic Spondylodiscitis in Adults

High index of suspicion, MRI, multidisciplinary collaboration, and CT-guided biopsy are the cornerstones for an early diagnosis of infectious spondylodiscitis. The incidence of spondylodiscitis admissions is increasing. A notable proportion of patients present with neurological deficit. Unfortunately, IV drug users, frail and immunocompromised patients, and patients with HIV are most susceptible to have pyogenic spondylodiscitis and its complications. These infections have a mortality rate of up to 20%. Pyogenic spondylodiscitis should be managed with at least 6 weeks of IV antibiotics. It is best to involve an infectious disease specialist because of the wide variety of organisms involved and the emergence of resistance. Neurological deficits, instability, pain, deformity, and frailty are the factors that decide whether and when to perform surgery. Surgery can reduce morbidity, mortality, and length of hospital stay for these debilitating infections. Some studies have recommended stabilization without aggressive débridement, especially in frail patients. Implants (titanium and PEEK) as well as bone grafts (autograft and allograft) are safe in pyogenic spondylodiscitis. Minimally invasive spinal surgery reduces blood loss, surgical time, and hospital stay over classical open surgery. Endoscopic spine surgery is useful for debulking the infection and obtaining samples for diagnostic purposes.

An overview of magnesium-based implants in orthopaedics and a prospect of its application in spine fusion

Due to matching biomechanical properties and significant biological activity, Mg-based implants present great potential in orthopedic applications. In recent years, the biocompatibility and therapeutic effect of magnesium-based implants have been widely investigated in trauma repair. In contrast, the R&D work of Mg-based implants in spinal fusion is still limited. This review firstly introduced the general background for Mg-based implants. Secondly, the mechanical properties and degradation behaviors of Mg and its traditional and novel alloys were reviewed. Then, different surface modification techniques of Mg-based implants were described. Thirdly, this review comprehensively summarized the biological pathways of Mg degradation to promote bone formation in neuro-musculoskeletal circuit, angiogenesis with H-type vessel formation, osteogenesis with osteoblasts activation and chondrocyte ossification as an integrated system. Fourthly, this review followed the translation process of Mg-based implants via updating the preclinical studies in fracture fixation, sports trauma repair and reconstruction, and bone distraction for large bone defect. Furthermore, the pilot clinical studies were involved to demonstrate the reliable clinical safety and satisfactory bioactive effects of Mg-based implants in bone formation. Finally, this review introduced the background of spine fusion surgeryand the challenges of biological matching cage development. At last, this review prospected the translation potential of a hybrid Mg-PEEK spine fusion cage design.

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.

Diabetes-related Screw Loosening: The Distinction of Surgical Sites and the Relationship among Diabetes, Implant Stabilization and Clinical Outcomes

OBJECTIVES

Diabetes mellitus (DM) is correlated with poor clinical outcomes in spinal surgery. However, the effect of it on screw stabilization has not been investigated. The aim of this study was to evaluate the screw loosening rate and postoperative outcomes in diabetic patients and to identify potential risk factors associated with loosening.

METHODS

This was a retrospective study. Two hundred and forty-three patients who received cervical or lumbar internal fixation between 2015 and 2019 were enrolled. Screw loosening was assessed on radiography, and clinical outcomes were evaluated by the improvement of visual analogue scale (VAS), Oswestry disability index (ODI) or Japanese Orthopaedic Association (JOA) scores. The relationship of DM, screw loosening and clinical outcomes were analyzed with chi-square tests and regression analyses.

RESULTS

One hundred and twenty-two patients (50.2%) with diabetes were included in this study. Diabetes led to the increase of the rate of screw loosening in the lumbar spine, while the loosening rate did not vary significantly in the cervical spine. The occurrence of screw loosening in the lumbar spine was more likely to be associated with clinical outcomes for motor performance including walking and sitting. However, no significant effect on JOA and VAS scores in the cervical spine of screw loosening was found. Moreover, the history of DM affected the outcomes of the patients who underwent spinal surgery.

CONCLUSION

DM had an adverse effect on screw stabilization. The impaired improvement of clinical outcomes in diabetics after spinal surgery was related to screw loosening. In addition to the direct effects on operative wounds and neural function, the impact on the screws due to DM was also worth noting.

The one-stop-shop approach: Navigating lumbar 360-degree instrumentation in a single position

Objective

Treatment strategies of patients suffering from pyogenic spondylodiscitis are a controverse topic. Percutaneous dorsal instrumentation followed by surgical debridement and fusion of the infectious vertebral disc spaces is a common approach for surgical treatment. Technical advances enable spinal navigation for dorsal and lateral instrumentation. This report investigates combined navigated dorsal and lateral instrumentation in a single surgery and positioning for lumbar spondylodiscitis in a pilot series.

Methods

Patients diagnosed with 1- or 2-level discitis were prospectively enrolled. To enable posterior navigated pedicle screw placement and lateral interbody fusion (LLIF) patients were positioned semi-prone in 45-degree fashion. For spinal referencing, a registration array was attached to the pelvic or spinal process. 3D scans were acquired intraoperatively for registration and implant control.

Results

27 patients suffering from 1- or 2-level spondylodiscitis with a median ASA of 3 (1–4) and a mean BMI of 27.9 ± 4.9 kg/m2 were included. Mean duration of surgery was 146 ± 49 min. Mean blood loss was 367 ± 307 ml. A median of 4 (4–8) pedicle screws were placed for dorsal percutaneous instrumentation with an intraoperative revision rate of 4.0%. LLIF was performed on 31 levels with an intraoperative cage revision rate of 9.7%.

Conclusions

Navigated lumbar dorsal and lateral instrumentation in a single operation and positioning is feasible and safe. It enables rapid 360-degree instrumentation in these critically ill patients and potentially reduces overall intraoperative radiation exposure for patient and staff. Compared to purely dorsal approaches it allows for optimal discectomy and fusion while overall incisions and wound size are minimized. Compared to prone LLIF procedures, semi-prone in 45-degree positioning allows for a steep learning curve due to minor changes of familiar anatomy.

CFR-PEEK Pedicle Screw Instrumentation for Spinal Neoplasms: A Single Center Experience on Safety and Efficacy

Simple Summary

Advances in screening methods and new therapeutic strategies have lead to a continuous decline in cancer death rates, especially over the last ten years. As a consequence, the number of patients with spinal metastases is increasing. In modern oncological treatment surgery followed by postoperative radiotherapy for spinal metastases has gained a decisive role. For spinal stabilization, pedicle screws and rods are used. They used to be made of titanium or cobalt–chrome alloys. Recently, carbon-fiber-reinforced (CFR) polyethyl-ether-ether-ketone (PEEK) was introduced as a new material reducing artifacts on imaging and showing less perturbation effects on photon radiation. The aim of this study is to report on the safety and efficacy of CFR-PEEK pedicle screw systems for spinal neoplasms in a large cohort of consecutive patients. We could show that implant-related complications, such as intraoperative screw breakage and screw loosening, were rare. So, we conclude that CFR-PEEK is a safe and efficient alternative to titanium for oncological spinal instrumentation.

Abstract

(1) Background: Surgery for spinal metastases has gained a decisive role in modern oncological treatment. Recently, carbon-fiber-reinforced (CFR) polyethyl-ether-ether-ketone (PEEK) pedicle screw systems were introduced, reducing artifacts on imaging and showing less perturbation effects on photon radiation. Preliminary clinical experience with CFR-PEEK implants for spinal metastases exists. The aim of this monocentric study is to report on the safety and efficacy of CFR-PEEK pedicle screw systems for spinal neoplasms in a large cohort of consecutive patients. (2) Methods: We retrospectively analyzed prospectively the collected data of consecutive patients being operated on from 1 August 2015 to 31 October 2021 using a CFR-PEEK pedicle screw system for posterior stabilization because of spinal metastases or primary bone tumors of the spine. (3) Results: We included 321 patients of a mean age of 65 ± 13 years. On average, 5 ± 2 levels were instrumented. Anterior reconstruction was performed in 121 (37.7%) patients. Intraoperative complications were documented in 30 (9.3%) patients. Revision surgery for postoperative complications was necessary in 55 (17.1%) patients. Implant-related complications, such as intraoperative screw breakage (3.4%) and screw loosening (2.2%), were rare. (4) Conclusions: CFR-PEEK is a safe and efficient alternative to titanium for oncological spinal instrumentation, with low complication and revision rates in routine use and with the advantage of its radiolucency.