The safety and efficacy of cadaveric allografts and titanium cage as a fusion substitutes in pyogenic osteomyelitis

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.

A novel nanohydroxyapatite/polyamide 66 strut for reducing subsidence after one-level anterior cervical corpectomy and fusion: a finite-element study

BACKGROUND

The aim of this study is to introduce a novel nanohydroxyapatite/polyamide 66(n-HA/PA66)n strut to improve biomechanical performance and reduce subsidence.

METHODS

One validated intact and 2 ACCF-simulated C3-C7 cervical spine models were developed (old strut: Group A, new strut: Group B). In the ACCF models, C5 underwent corpectomy and was fixed by an anterior cervical plate. Screw angles were categorized as 1 (0 ) and 2 (45 ) and divided into 4 groups, A1, A2, B1 and B2, for each model. An axial force of 74 N and a moment couple of 1.0 Nm were imposed on the C3 vertebra. The range of motion (ROM) of each segment and the stress distribution on the screw-vertebra interface, strut, and strut-endplate interface were recorded and analysed.

RESULTS

There was no significant difference in ROM between Group A and Group B during bending, extension and rotation under 74 N axial pressure. The stress concentration on the strut body in Group A was higher than that in Group B. The peak stress values at the screw-vertebral interface in Groups A1 and A2 were higher than those in Groups B1 and B2, except for during extension and lateral bending. Under axial pressure, the peak stress values at the strut body-endplate interface during bending, extension and rotation were lower in the A1 and A2 groups than in the B1 and B2 groups. The Group B model showed much higher graft stress than the Group A model.

CONCLUSIONS

Based on finite-element analysis, compared with the old strut, the novel strut showed better biomechanical performance at the screw-vertebra interface.

Clinical Outcomes and Cost Profiles for Cage and Allograft Anterior Cervical Discectomy and Fusion Procedures in the Adult Population: A Propensity Score-Matched Study

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To characterize the postoperative outcomes and economic costs of anterior cervical discectomy and fusion (ACDF) procedures using synthetic biomechanical intervertebral cage (BC) and structural allograft (SA) implants.

OVERVIEW OF LITERATURE

ACDF is a common spine procedure that typically uses an SA or BC for the cervical fusion. Previous studies that compared the outcomes between the two implants were limited by small sample sizes, short-term postoperative outcomes, and procedures with single-level fusion.

METHODS

Adult patients who underwent an ACDF procedure in 2007-2016 were included. Patient records were extracted from MarketScan, a national registry that captures person-specific clinical utilization, expenditures, and enrollments across millions of inpatient, outpatient, and prescription drug services. Propensity-score matching (PSM) was employed to match the patient cohorts across demographic characteristics, comorbidities, and treatments.

RESULTS

Of 110,911 patients, 65,151 (58.7%) received BC implants while 45,760 (41.3%) received SA implants. Patients who underwent BC surgeries had slightly higher reoperation rates within 1 year after the index ACDF procedure (3.3% vs. 3.0%, p=0.004), higher postoperative complication rates (4.9% vs. 4.6%, p=0.022), and higher 90-day readmission rates (4.9% vs. 4.4%, p =0.001). After PSM, the postoperative complication rates did not vary between the two cohorts (4.8% vs. 4.6%, p=0.369), although dysphagia (2.2% vs. 1.8%, p<0.001) and infection (0.3% vs. 0.2%, p=0.007) rates remained higher for the BC group. Other outcome differences, including readmission and reoperation, decreased. Physician's fees remained high for BC implantation procedures.

CONCLUSIONS

We found marginal differences in clinical outcomes between BC and SA ACDF interventions in the largest published database cohort of adult ACDF surgeries. After adjusting for group-level differences in comorbidity burden and demographic characteristics, BC and SA ACDF surgeries showed similar clinical outcomes. Physician's fees, however, were higher for BC implantation procedures.

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.

Management of vertebral osteomyelitis in adults

Vertebral osteomyelitis is a condition that predominantly affects older men with chronic comorbidities, such as diabetes, renal and hepatic failure, or immunosuppression. Symptoms develop insidiously and a high index of suspicion is required to diagnose the condition; this is achieved through serological testing and imaging. The mainstay of treatment is long-term antibiotic therapy, lasting a minimum of 6 weeks; however, surgical debridement with stabilisation is required when conservative treatment is proving ineffective and infection progresses. It is critically important that sufficient treatment is provided for those experiencing vertebral osteomyelitis, as not doing so could lead to severe neurological compromise and death.

Safety and Feasibility of DTRAX Cervical Cages in the Atlantoaxial Joint for C1/2 Stabilization

BACKGROUND

Pathological changes in the atlantoaxial joint often lead to instability, pain, and neurological deterioration. One treatment option is the surgical stabilization of the atlantoaxial joint. In other areas of the spine, fusion rates have been improved by the introduction of an interbody cage. Our aim was to use cervical interbody spacers, originally designed to augment fusion across subaxial posterior cervical facets, to optimize the conditions for atlantoaxial fusion.

OBJECTIVE

To evaluate the safety and efficacy of implanting cervical cages in the atlantoaxial joint for C1/2 stabilization.

METHODS

Our retrospective study evaluated patients who had undergone C1/2 cervical fusions by the Harms/Goel technique. This technique was modified by implanting a titanium cervical interbody spacer into the joint space. Mean overall pain, as measured by a 0 to 10 visual analog scale (VAS) and neurological outcomes were measured preoperatively and postoperatively. In addition, radiological outcomes were collected using follow-up imaging.

RESULTS

Nine patients were included in this case series. The mean preoperative VAS for overall pain was 5.0 ± 4.0, which changed to a mean VAS of 2.0 ± 3.0 after an average follow-up period of 41.4 ± 20.4 (P = .043). All patients showed a bony fusion in our case series. None of the radiological imaging during follow-up showed screw loosening, hardware breakage, implant migration, or nonunion.

CONCLUSION

The implantation of cervical titanium cages into the atlantoaxial joint in combination with posterior fixation appears to be a safe and effective method for achieving C1/2 fusion.

Recent advances in the local antibiotics delivery systems for management of osteomyelitis

Chronic osteomyelitis is a challenging disease due to its serious rates of mortality and morbidity while the currently available treatment strategies are suboptimal. In contrast to the adopted systemic treatment approaches after surgical debridement in chronic osteomyelitis, local drug delivery systems are receiving great attention in the recent decades. Local drug delivery systems using special carriers have the pros of enhancing the feasibility of penetration of antimicrobial agents to bone tissues, providing sustained release and localized concentrations of the antimicrobial agents in the infected area while avoiding the systemic side effects and toxicity. Most important, the incorporation of osteoinductive and osteoconductive materials in these systems assists bones proliferation and differentiation, hence the generation of new bone materials is enhanced. Some of these systems can also provide mechanical support for the long bones during the healing process. Most important, if the local systems are designed to be injectable to the affected site and biodegradable, they will reduce the level of invasion required for implantation and can win the patients’ compliance and reduce the healing period. They will also allow multiple injections during the course of therapy to guard against the side effect of the long-term systemic therapy. The current review presents different available approaches for delivering antimicrobial agents for the treatment of osteomyelitis focusing on the recent advances in researches for local delivery of antibiotics.

HIGHLIGHTS

Chronic osteomyelitis is a challenging disease due to its serious mortality and morbidity rates and limited effective treatment options.

Local drug delivery systems are receiving great attention in the recent decades.

Osteoinductive and osteoconductive materials in the local systems assists bones proliferation and differentiation

Local systems can be designed to provide mechanical support for the long bones during the healing process.

Designing the local system to be injectable to the affected site and biodegradable will reduces the level of invasion and win the patients’ compliance.

Spondylodiscitis treated with freeze-dried bone allograft alone or combined with autograft: A randomized and blinded trial

PURPOSE

To compare the bone fusion of freeze-dried allograft alone versus freeze-dried allograft combined autograft in spinal instrumentation due to spondylodiscitis.

METHODS

A randomized prospective trial of patients with spondylodiscitis treated with surgical debridement and spinal fixation with freeze-dried bone allograft and autograft (Group 1) or freeze-dried bone allograft alone (Group 2) was performed. Patient follow-up was assessed with a CT-scan for bone fusion; consecutive serum inflammatory marker detection (C-reactive protein, [CRP], and erythrocyte sedimentation rate, [ESR]) and clinical assessment (pain, functional disability, and spinal cord injury recovery) were other outcome parameters. The primary outcome was the grade of bone allograft integration with the scale of Tan (which ranges from 1 to 4, with lower scores indicating a better fusion rate) at 1 year after surgery.

RESULTS

A total of 20 patients were evaluated, 13 (65%) men and 7 (35%) women with a mean age of 47.2 (±14.3) years. Homogeneous distribution of demographic data was observed. A similar satisfactory bone graft fusion grade was observed in both graft groups at 1 year after surgery (p = 1.0000). Serum inflammatory markers gradually decreased in both groups after surgical intervention (CRP, p < 0.001; ESR, p < 0.01). At one-year follow-up, gradual improvement of pain, functional disability, and neurological spinal injury recovery in both graft groups were achieved.

CONCLUSION

Freeze-dried allograft alone could be a therapeutic option for spinal fixation surgery due to spondylodiscitis since it achieves a satisfactory graft fusion rate and clinical improvement.

LEVEL OF EVIDENCE

Level 1. Treatment.

REGISTER

NCT03265561.

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.

Evaluation and Management of Pyogenic and Tubercular Spine Infections

PURPOSE OF REVIEW

To review the most current diagnostic tools and treatment options for pyogenic and tubercular spine infection.

RECENT FINDINGS

Recent studies have focused on risk factors for failed nonoperative management in order to improve patient selection. Also, spine instrumentation and different grafting options have been safely utilized in the setting of an active infection without increasing the incidence of reoccurrence. However, the optimal surgical technique has yet to be established and instead should be patient specific. Spine infections include a broad spectrum of disorders including discitis, vertebral osteomyelitis, and spinal epidural abscess. It is paramount to recognized spine infections early due to the potential catastrophic consequences of paralysis and sepsis. The management of spine infections continues to evolve as newer diagnostic tools and surgical techniques become available. Magnetic resonance imaging with contrast is the imaging study of choice and computed tomography-guided biopsies are crucial for guiding antibiotic selection. Antibiotics are the mainstay of treatment and surgery is indicated in patients with neurological deficits, sepsis, spinal instability, and those who have failed nonoperative treatment.

A Novel Anterior Transpedicular Screw Artificial Vertebral Body System for Lower Cervical Spine Fixation: A Finite Element Study

A finite element model was used to compare the biomechanical properties of a novel anterior transpedicular screw artificial vertebral body system (AVBS) with a conventional anterior screw plate system (ASPS) for fixation in the lower cervical spine. A model of the intact cervical spine (C3–C7) was established. AVBS or ASPS constructs were implanted between C4 and C6. The models were loaded in three-dimensional (3D) motion. The Von Mises stress distribution in the internal fixators was evaluated, as well as the range of motion (ROM) and facet joint force. The models were generated and analyzed by mimics, geomagic studio, and ansys software. The intact model of the lower cervical spine consisted of 286,382 elements. The model was validated against previously reported cadaveric experimental data. In the ASPS model, stress was concentrated at the connection between the screw and plate and the connection between the titanium mesh and adjacent vertebral body. In the AVBS model, stress was evenly distributed. Compared to the intact cervical spine model, the ROM of the whole specimen after fixation with both constructs is decreased by approximately 3 deg. ROM of adjacent segments is increased by approximately 5 deg. Facet joint force of the ASPS and AVBS models was higher than those of the intact cervical spine model, especially in extension and lateral bending. AVBS fixation represents a novel reconstruction approach for the lower cervical spine. AVBS provides better stability and lower risk for internal fixator failure compared with traditional ASPS fixation.

Mesh cage for treatment of hematogenous spondylitis and spondylodiskitis. How safe and successful is its use in acute and chronic complicated cases? A systematic review of literature over a decade

BACKGROUND

Surgical treatment of hematogenous pyogenic spondylitis and spondylodiskitis includes anterior debridement, stabilization, and fusion. Titanium mesh cage (TMC) has been advocated to immediately correct deformity and eradicate infection with low recurrence rates. There are no comprehensive reviews on TMC.

PURPOSE

To evaluate recorded information regarding surgical outcome with the use of TMC for treating patients with pyogenic spinal infection.

STUDY DESIGN

Comprehensive review.

METHODS

The terms "titanium cage", "spine", "infection" were searched. A total of 486 peer-reviewed papers published from 2002 to 2012 were obtained from PubMed search. Fifteen Level IV articles with 363 patients were enrolled for consideration. Finally, 192 (53 %) patients who received TMC were eligible and included in this review. Age, comorbidities, indications for surgery, abscess formation, time lapsed between symptoms initiation and surgery, microbiology, radiological spine restoration, neurological outcome, and complications following surgery are evaluated.

RESULTS

The average age at the index surgery was 57 years, range 15-85 years. The reported time lapsed from symptoms presentation to diagnosis varied significantly from 1 week to 2 years. On admission, there reported paravertebral and/or epidural abscess in 48 % and neurological impairment in 51 % of the patients. One hundred and seventy-seven comorbidities were recorded in 192 patients. Bone biopsy and culture revealed gram (+) bacteria in 71 %, gram (-) in 24 %, and multiple bacteria in 1 %, while it was negative in 3.1 % of the patients. TMC was most commonly (49 %) implanted in the lumbar spine. The follow-up observation following surgery averaged 26 months, range 10-116 months. Most of the studies reported decrease in segmental kyphosis and neurological improvement in incomplete lesions postoperatively. TMC was primarily revised for early dislodgment or cage misplacement in 3.2 % of the patients. Infection recurrence was recorded in two patients (1.3 %), but revision surgery needed in one (0.65 %) patient. Mortality was reported in 5.8 % of the patients.

CONCLUSIONS

TMC offers an advantageous and safe technique for spinal debridement and fusion for hematogenous spinal infection. TMC safeguarded medium-term spinal stability with low infection recurrence rates, which were independent form causative pathogen, age, and comorbidities.

Evaluation of a new type of titanium mesh cage versus the traditional titanium mesh cage for single-level, anterior cervical corpectomy and fusion

STUDY DESIGN

A retrospective review of prospectively collected data in an academic institution.

OBJECTIVE

To evaluate the safety and efficacy of a new type of titanium mesh cage (TMC) in single-level, anterior cervical corpectomy and fusion (ACCF).

METHODS

Fifty-eight patients consecutive with cervical spondylotic myelopathy (CSM) from cervical degenerative spondylosis and isolated ossification of the posterior longitudinal ligament were treated with a single-level ACCF using either a new type of TMC (28 patients, group A) or the traditional TMC (30 patients, group B). We evaluated the patients for TMC subsidence, cervical lordosis (C2-C7 Cobb and Cobb of fused segments) and fusion status for a minimum of 30 months postoperatively based on spine radiographs. In addition, neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) scores. Neck pain was evaluated using a 10-point visual analog scale (VAS).

RESULTS

The loss of height of the fused segments was less for group A than for group B (0.8 ± 0.3 vs. 2.8 ± 0.4 mm) (p < 0.01); also, there was a lower rate of severe subsidence (≥3 mm) in group A (4 %, 1/28) than in group B (17 %, 5/30) (p < 0.01). There were no differences in the C2-C7 Cobb and Cobb of fused segments between the groups preoperatively or at final follow-up (p > 0.05), but the Cobb of fused segments immediately postoperative were significantly less for group B than for group A (p < 0.01). All patients, however, had successful fusion (100 %, each). Both groups had marked improvement in the JOA score after operation (p < 0.01), with no significant differences in the JOA recovery ratio (p > 0.05). The postoperative VAS neck pain scores for group A were significantly less than that for group B (p < 0.05); severe subsidence was correlated with neck pain.

CONCLUSIONS

The new type of TMC provides comparable clinical results and fusion rates with the traditional TMC for patients undergoing single-level corpectomy. The new design TMC decreases postoperative subsidence (compared to the traditional TMC); the unique design of the new type of TMC matches the vertebral endplate morphology which appears to decrease the severity of subsidence-related neck pain in follow-up.