[Pyogenic spondylodiscitis: therapy algorithm and a new classification for therapeutic decision-making]

Value of [18F]FDG PET/CT in Diagnosis and Management of Spondylodiscitis

Vertebral osteomyelitis is the third most common form of osteomyelitis in patients over 50 years of age.Whereas prompt (pathogen-directed) therapy is crucially associated with better outcomes, the heterogeneous clinical presentation of disease with unspecific symptoms often delays adequate treatment initiation. Diagnosis requires a careful investigation of medical history, clinical findings and diagnostic imaging, including magnetic resonance imaging and nuclear medicine techniques.Due to its high sensitivity, [18F]FDG PET/CT is becoming increasingly important in diagnosis and management of spondylodiscitis, especially in the postoperative setting with presence of spinal hardware or other implantable devices in which MRI is limited.

Value of [18F]FDG PET/CT in diagnosis and management of spondylodiscitis

Vertebral osteomyelitis is the third most common form of osteomyelitis in patients over 50 years of age.Whereas prompt (pathogen-directed) therapy is crucially associated with better outcomes, the heterogeneous clinical presentation of disease with unspecific symptoms often delays adequate treatment initiation. Diagnosis requires a careful investigation of medical history, clinical findings and diagnostic imaging, including magnetic resonance imaging and nuclear medicine techniques.Due to its high sensitivity, [¹⁸F]FDG PET/CT is becoming increasingly important in diagnosis and management of spondylodiscitis, especially in the postoperative setting with presence of spinal hardware or other implantable devices in which MRI is limited.

A new classification of spondylodiscitis: possibility of validation and multidisciplinary expert consensus

Objective. To perform validation study of the E. Pola classification (2017) and to assess expert consensus on the diagnosis and treatment of infectious lesions of the spine in the national professional community.

Material and Methods. A clinical and radiological database on 15 cases of infectious spondylitis, as well as the information about original article by Pola and a Russian translation of the classification and tactical tables from this article, were distributed to 408 orthopedic traumatologists, neurosurgeons and radiologists who have experience in treating patients with spinal pathology and whose data are available in the registers of the relevant professional associations of the Russian Federation. The coincidence/difference in the responses concerning the definition of lesion types and the choice of treatment tactics, as well as proposals for the use of classification were assessed.

Results. Answers were obtained from 37 respondents from 11 regions of the Russian Federation. The general interobserver agreement index (Fleiss kappa) for all types of spondylodiscitis was 0.388 (95 % CI 0.374–0.402), including for lesion types: type A – 0.480 (95 % CI 0.460–0.499, type B – 0.300 (95 % CI 0.281–0.320), and type C – 0.399 (95 % CI 0.380–0.419). Agreement levels were higher among radiologists (type A – 0.486, type B – 0.484, and type C – 0.477), orthopedic traumatologists (type A – 0.474, type B – 0.380, and type C – 0.479), and specialists with clinical experience less than 10 years (type A – 0.550, type B – 0.318, and type C – 0.437). The pooled data for all 12 lesion subtypes showed general poor agreement (k = 0.247, CI 0.240–0.253), satisfactory level was found for B3.2 type (k = 0.561, CI 0.542–0.581), good agreement (k > 0.61) was achieved between orthopedic traumatologists for type B3.2 and between radiologists for B3.1 and B3.2 lesion types. Respondents refused to use basic treatment options for type A in 15.1 %, type B in 7.5 % and type C in 3.2 % of answers, while indicating the need for interventions through anterior approach in 24.7 %, 43.0 % and 46.2 %, respectively. Limitations of the classification use depending on the localization and etiology of spondylitis were noted. Authors recommended taking into account the presence of systemic inflammatory response syndrome, mandatory CT scanning, clarification of spinal instability criteria, and the addition of anterior surgical interventions to the treatment algorithm.

Conclusion. The Pola classification of spondylodiscitis is currently considered the most successful for tactical algorithms and implementation in broad clinical practice for spondylodiscitis. However, at the stages of its clinical application, there is an unsatisfactory interobserver expert consensus on the types of lesions, and there are limitations related to the etiology, localization and severity of the disease. A modified classification taking into account the identified limitations and including anterior procedures in the tactical options is advisable.

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.

[Pyogenic spondylodiscitis: symptoms, diagnostics and therapeutic strategies]

BACKGROUND

Pyogenic spondylodiscitis is a rare disease that is being diagnosed with increasing frequency in recent years. It is associated with a high morbidity and mortality.

DIAGNOSIS

Often, because of its nonspecific symptoms, pyogenic spondylodiscitis is diagnose with some delay. In addition to pathogen detection, MRI is the gold standard to diagnose pyogenic spondylodiscitis. Also, x-ray imaging and CT can be carried out for surgical planning and for subsequent follow-up imaging. If blood or tissue cultures are negative, open surgical biopsies should be preferred over CT-guided biopsies.

THERAPY

The therapy can be conservative, such as immobilization, as well as antibiotics and analgesics, or surgical. If, for example, neurological deficits, spinale instabilities or deformities, septic disease progression or extensive abscess formations are present, surgical therapy is indicated. The surgical treatment strategies depend on the severity of the disease.

OUTLOOK

The prognosis is dependent on a rapid diagnosis and a swift start to therapy. There is no clear evidence with regard to treatment options (conservative vs. surgical therapy).

Pyogenic spondylodiscitis : The quest towards a clinical-radiological classification

BACKGROUND

Pyogenic spondylodiscitis (PS) is a debilitating condition laden with orthopedic and neurological complications. The choice of the best step in management is often delayed due to the controversy encompassing its multiple facets. Several classification systems were proposed in the literature to define optimal management; however, consensus was not achieved.

OBJECTIVE

The aim of this study was to review the literature and critically appraise the classification systems of PS and the rationale behind the classification criteria.

METHODS

A literature search was conducted in PubMed. Titles and abstracts of articles were searched using different synonyms of spondylodiscitis and its classification. No restrictions regarding language of publication or date of publication were applied.

RESULTS

A total of 43 papers with 5 encompassing 3 main classifications were found in the literature. These classifications were overlapping but different. They encompassed neurologic deficits, abscess formation and segmental instability, laboratory parameters and morphological changes in magnetic resonance imaging (MRI) as the most important factors used to classify PS, assess the severity and guide treatment.

CONCLUSION

The current classification schemes overlap and encompass the most clinically relevant factors; however, some could be too complex for interdisciplinary clinical practice and do not adequately address unique entities, such as PS of the cervical spine, anterolisthesis and retrolisthesis. Most importantly, some criteria must be utilized in concert with recently published guidelines and should be re-assessed for validity and reliability. A uniform orthopedic parlance is required to optimize the management of this debilitating and life-threatening condition.

A unilateral less invasive posterolateral approach for disc debridement and titanium cage insertion supplemented by contralateral transfascial screw fixation for high-morbidity patients suffering from septic thoracolumbosacral spondylodiscitis

PURPOSE

This case series reports on the efficacy and safety of a less invasive posterolateral approach for septic thoracolumbosacral spondylodiscitis in high-morbidity patients.

METHODS

Twenty consecutive severe sick (ASA > III) patients (14 men and 6 women), with an average age of 64 ± 14 years, suffering from septic subacute and chronic thoracolumbosacral spondylodiscitis were selected to undergo a one-stage less invasive unilateral posterolateral disc space debridement, supplemented by an ipsilateral titanium cage implantation and pedicle screw fixation plus a contralateral transfascial pedicle screw fixation.

RESULTS

Two high-risk patients with severe comorbidities (ASA stage IV and V, respectively) died on days 1 and 8 postoperatively because of non-surgical complications such as massive lung embolism and acute myocardial infract, respectively. Three patients with incomplete paraplegia (ASIA C) preoperatively were improved after the surgery to ASIA D (two patients) and E (one patient), respectively, while there was no neurological deterioration in any patient postoperatively. From the 18 patients that survived, ten patients were available for the final follow-up 8.8 ± 2.7 years postoperatively. In two patients with spondylodiscitis caused by gram(-) bacteria, the posterior instrumentation was finally removed because of asymptomatic fistula emerging from posterior instrumentation solely, 15 and 19 months after surgery. The survivals at 2.5 and 10 years with revision as end point was 87.4% (95% CI 58.1-96.7); while in the "worst case scenario" the survivals at 2.5 and 10 years were: 66.7% (95% CI 40.4-83.4%); 47.7% (95% CI 23.2-68.8%) and 47.7% (95% CI 23.2-68.8%), respectively.

CONCLUSIONS

The less invasive posterolateral approach for disc debridement and titanium cage insertion seems to be an alternative surgery for severe sick adult immunosuppressed patients with septic thoracolumbosacral spondylodiscitis that cannot tolerate traditional open transthoracic, thoracolumbar, retroperitoneal or combined approaches. The study has been registered in the Public Registry ClinicalTrials.gov PRS with the ID: NCT03472131.

Outcome of Transforminal Lumbar Thorough Debridement, Decompression, and Spondylodesis Technique in Treatment of 25 Patients with Pyogenic Spondylodiscitis

BACKGROUND

Lumbar pyogenic spondylodiscitis (LPS) is still a tangled problem in its management, especially with increasing rates of cases who underwent different spinal procedures and in patients with chronic medical disease. One-stage posterior direct transforminal lumbar thorough debridement of septic lesion, decompression, and spondylodesis (TLTDDS) are the main goals in treatment of complicated LPS without additional morbidity of anterior surgery. This is a retrospective assessment of the clinical, laboratory, functional, and radiologic outcomes in 25 patients with LPS who underwent the TLTDDS procedure.

METHODS

Twenty-nine patients with complicated LPS were treated surgically by TLTDDS surgery from January 2014 to August 2017. Complete records of 25 patients were available for evaluation. All patients were examined clinically for back or leg pain using a visual analog scale (VAS) and neurological assessment by the American Spine Injury Association. Perioperative outcome and complications were documented. All patients were serially followed up between 12 and 32 months as regard pain (VAS), functional status by Kirkaldy Willis criteria, and Oswestry disability index, laboratory, and radiologic outcomes (angle of segmental kyphosis, lumbar lordosis correction, and fusion criteria).

RESULTS

Definitive solid bony fusion was seen between 6 and 14 months, except in 3 cases, which showed probable fusion. There was significant improvement in VAS, American Spine Injury Association index, laboratory investigations, and Oswestry disability index. One patient (5%) had transient neurological deficit, which resolved completely within 2 months.

CONCLUSIONS

TLTDDS surgery is an effective procedure in the treatment of symptomatic LPS and allows abscess evacuation with adequate neural decompression, segmental kyphosis correction, and functional improvement.

[Chameleon spondylodiscitis : Challenge for geriatricians]

The incidence of spondylodiscitis is increasing and attributable to an aging population with multimorbidities. Spondylodiscitis represents a life-threatening disease. Typical clinical manifestations often involve nonspecific symptoms with back pain; however, due to the frequent absence of fever the disease is often overlooked. Pathogen detection and spinal imaging with magnetic resonance imaging (MRI) are essential for the diagnosis. Identification of the causative pathogen is particularly important for initiating targeted antibiotic treatment. Debridement and stabilization are the mainstays of surgical management, even though foreign material must be implanted into the focus of inflammation.

[Chameleon spondylodiscitis : Challenge for geriatricians]

The incidence of spondylodiscitis is increasing and attributable to an aging population with multimorbidities. Spondylodiscitis represents a life-threatening disease. Typical clinical manifestations often involve nonspecific symptoms with back pain; however, due to the frequent absence of fever the disease is often overlooked. Pathogen detection and spinal imaging with magnetic resonance imaging (MRI) are essential for the diagnosis. Identification of the causative pathogen is particularly important for initiating targeted antibiotic treatment. Debridement and stabilization are the mainstays of surgical management, even though foreign material must be implanted into the focus of inflammation.

Single-stage debridement and spinal fusion using PEEK cages through a posterior approach for eradication of lumbar pyogenic spondylodiscitis: a safe treatment strategy for a detrimental condition

Background

Pyogenic infections of the lumbar spine are a rare but critical pathology, yet with considerably high mortality rates. In cases indicating surgical therapy, the implantation of titanium cages or autologous bone grafts represent today's gold standard. Although non-metallic implants such as poly-ether-ether-ketone (PEEK) have proven to be advantageous in diverse degenerative conditions, their saftey and practicability in lumbar spine infection remains questionable. Moreover, the efficacy of a single-step radical debridement of the infected disc space with subsequent fusion from a strictly posterior approach continues to be an issue of debate. We therefore sought to evaluate the feasibility, clinical and radiological outcome of a single-step TLIF procedure using oblique PEEK cages in the surgical management of patients with lumbar pyogenic spondylodiscitis.

Methods

From January 2009 through December 2013, all patients meeting the indication for surgical treatment of lumbar pyogenic spondylodiscitis were included. Patients demonstrating intact cortical bone on preoperative CT received a single-step radical debridement of the infected intervertebral disc space, posterior screw-and-rod instrumentation and implantation of an oblique PEEK cage using the TLIF technique. Oral antibiotics were continued for 12 weeks postoperatively and clinical and radiological results recorded throughout a minimum 1-year clinical follow-up.

Results

A total of 104 patients were admitted to receive surgical therapy for lumbar pyogenic spondylodiscitis. Within this patient population, 18 patients met the diagnostic criteria to receive the implantation of an oblique PEEK cage. Pathogens were detected in 13 cases with Staph. aureus being the predominant causative organism. All patients were discharged to recover in their domestic environment. Throughout the first year of clinical and radiological follow-up and beyond, none of the 18 patients demonstrated any signs of residual neurologic deficits or recurrent infection. Furthermore, two-plane conventional X-rays showed no significant implant subsidence or failure at any of the given time-points in up to 5 years postoperatively.

Conclusions

In patients meeting the criteria for surgical treatment of lumbar pyogenic spondylodiscitis, the implantation of PEEK cages using a single-step TLIF approach is a safe and feasible procedure. Based on our experience, the concern of a recurrent infection when implanting non-metallic cages may be refuted in carefully selected patients.

[Dorsolateral access and interbody spinal fusion in spondylodiscitis of the thoracolumbar spine (TLIF technique)]

SURGICAL GOAL: Resolve infection and achieve primary stability of instrumentation and permanent fusion of the affected spinal segment by means of debridement of the focus of infection. Defect-filling using autologous/allograft bone or a spacer, as well as immobilization by means of dorsal instrumentation.

INDICATION

Acute and chronic thoracolumbar spondylodiscitis.

CONTRAINDICATIONS

Purely epidural abscesses requiring only decompression (fenestration). Defects whose size make a ventral approach necessary.

SURGICAL TECHNIQUE

Classic dorsal approach to the thoracolumbar spine. Pedicle placed using screws depending on the size of the spinal defect for mono-, bi-, or multisegmental spinal fusion. Exposure performed at the level of the infected spinal disc or vertebral body on the more strongly affected side. Focus of infection removed. Depending on the degree of infection, defect filling is carried out using autologous bone or cancellous allograft, followed by rod assembly.

POSTOPERATIVE MANAGEMENT

Back brace-free follow-up treatment, physiotherapy and back training. Antibiotic administration until inflammation values fall within the normal range, or for at least 14 days.

RESULTS

Successful fusion of affected segments, including resolution of infection, is reported in over 90% of cases described in the literature. The revision rate among our mostly multimorbid patient group with an average age of 66 years was 16%. Of 39 of the 114 (34%) patients with preoperative neurological deficits, 26 (66%) demonstrated postoperative regression. Nine patients (23%) showed no improvement, whilst exacerbation of existing neurological deficits was seen in four patients (11%). Staphylococcus was the major pathogen in 34% of cases.