Infection with spinal instrumentation: Review of pathogenesis, diagnosis, prevention, and management

Risk Factors for Wound Infections after Deformity Correction Surgery in Neuromuscular Scoliosis

OBJECTIVE

This study aims to elucidate surgical risk factors in neuromuscular scoliosis (NMS) with respect to wound site infection after spinal fusion.

METHODS

A retrospective review was performed of all patients treated surgically for NMS between January 2008 and December 2016 (minimum 6 months' follow-up). A sub-cohort of 60 patients with minimum 2 years of follow-up data was also analyzed.

RESULTS

In 102 patients (53 boys and 49 girls), the mean age at surgery was 14.0 years (SD ±2.7). Mean follow-up was 2.53 years (±1.66), and mean time to presentation of infection was 2.14 months (±4.95). The overall perioperative complication rate was 26.5%, with 14.7% of patients developing deep wound infection. Gram-negative bacteria were responsible for 60% of infections; 20% were Gram positive, and 20% involved both types. Pulmonary comorbidities (p = 0.007), pre- to postoperative increase in weight (p = 0.010), exaggerated lumbar lordosis at follow-up (p = 0.008), history of seizures (p = 0.046), previous myelomeningocele repair (p = 0.046), and previous operations (p = 0.013) were significant risk factors for infection.

CONCLUSION

Our data suggest that in the pediatric population treated surgically for NMS, wound infection is strongly associated with postoperative increase in body weight, residual lumbar lordosis, pulmonary comorbidity, history of myelomeningocele repair, seizures, and previous operations.

Alcoholism as a predictor for pseudarthrosis in primary spine fusion: An analysis of risk factors and 30-day outcomes for 52,402 patients from 2005 to 2013

Introduction

This study assessed the incidence and risk factors for pseudarthrosis among primary spine fusion patients.

Methods

Retrospective review of ACS-NSQIP (2005-2013). Differences in comorbidities between spine fusion patients with and without pseudarthrosis (Pseud, N-Pseud) were assessed using chi-squared tests and Independent Samples t-tests. Binary logistic regression assessed patient-related and procedure-related predictors for pseudarthrosis.

Results

52,402 patients (57yrs, 53%F, 0.4% w/pseudarthrosis). Alcohol consumption (OR:2.6[1.2-5.7]) and prior history of surgical revision (OR:1.6[1.4-1.8]) were risk factors for pseudarthrosis operation. Pseud patients at higher risk for deep incisional SSI (at 30-days:OR:6.6[2.0-21.8]). Pseud patients had more perioperative complications (avg:0.24 ± 0.43v0.18 ± 0.39,p=0.026).

Conclusions

Alcoholism and surgical revision are major risk factors for pseudarthrosis in patients undergoing spine fusion.

Therapeutic outcome of spinal implant infections caused by Staphylococcus aureus: A retrospective observational study

Spinal implant infection is a rare but significant complication of spinal fusion surgery, and the most common pathogen is Staphylococcus aureus. It is difficult to treat due to this pathogen's biofilm-forming ability and antibiotic resistance. We evaluated the therapeutic outcome of treatments for S aureus spinal implant infections. We retrospectively reviewed all patients with S aureus spinal implant infections at 11 tertiary-care hospitals over a 9-year period. Parameters predictive of treatment failure and recurrence were analyzed by Cox regression. Of the 102 patients with infections, 76 (75%) were caused by methicillin-resistant S aureus (MRSA) and 51 (50%) were late-onset infections. In all, 83 (81%) patients were managed by debridement, antibiotics, and implant retention (DAIR) and 19 (19%) had their implants removed. The median duration of all antibiotic therapies was 52 days. During a median follow-up period of 32 months, treatment failure occurred in 37 (36%) cases. The median time to treatment failure was 113 days, being <1 year in 30 (81%) patients. DAIR (adjusted hazard ratio [aHR], 6.27; P = .01) and MRSA infection (aHR, 4.07; P = .009) were independently associated with treatment failure. Rifampin-based combination treatments exhibited independent protective effects on recurrence (aHR, 0.23; P = .02). In conclusion, among patients with S aureus spinal implant infections, MRSA and DAIR were independent risk factors for treatment failure, and these risk factors were present in the majority of patients. In this difficult-to-treat population, the overall treatment failure rate was 36%; rifampin may improve the outcomes of patients with S aureus spinal implant infections.

Real-Life Evidence for Tedizolid Phosphate in the Treatment of Cellulitis and Wound Infections: A Case Series

Introduction

Tedizolid phosphate 200 mg, once daily for 6 days, has recently been approved for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSIs) in several countries; however, clinical experience in real-life settings is currently limited. Here, we report on the use of tedizolid with an extended treatment duration for complex and severe ABSSSIs in real-world clinical settings.

Methods

Two patients with cellulitis and two patients with surgical site infection (SSI), aged 26–60 years, were treated with tedizolid phosphate 200 mg, intravenous/oral (IV/PO) or IV only, once daily at four different institutions.

Results

Two morbidly obese patients had non-necrotizing, non-purulent severe cellulitis, which were complicated by sepsis or systemic inflammatory response syndrome plus myositis. One female patient failed on first-line empiric therapy with IV cefalotin, clindamycin and imipenem (3–4 days), and was switched to IV/PO tedizolid (7 + 5 days). One male patient received IV clindamycin plus IV/PO tedizolid (5 + 5 days), but clindamycin was discontinued on Day 3 due to an adverse event. For both patients, clinical signs and symptoms improved within 72 h, and laboratory results were normalized by Days 7 and 8, respectively. Two other patients (one obese, diabetic female with chronic hepatitis and chronic obstructive pulmonary disease) had complicated SSIs occurring 10 days after hernia repair with mesh or 3 months after spinal fusion surgery with metal implant. First patient with previous methicillin-resistant Staphylococcus aureus (MRSA) bacteremia received a 7-day tedizolid IV course empirically. The second patient with culture-confirmed MRSA infection received a 14-day IV course. Both patients responded within 72 h, and local and systemic signs normalized by end of treatment. There were no reports of thrombocytopenia.

Conclusion

Tedizolid phosphate 200 mg for 7–14 days was a favored treatment option for patients with severe/complex ABSSSIs, and was effective following previous treatment failure or in late-onset infections.

Funding

Editorial assistance and the article processing charges were funded by Bayer AG, Berlin, Germany.

The effectiveness of pedicle screw immersion in vancomycin and ceftriaxone solution for the prevention of postoperative spinal infection: A prospective comparative study

OBJECTIVE

The aim of this study was to evaluate the efficacy of the local application of vancomycin hydrochloride (HCl)-ceftriaxone disodium hemiheptahydrate onto implants before using them to prevent postoperative infection.

METHODS

The study included 239 patients (153 women and 86 men; mean age: 48.23 ± 16.77 years) who had thoracolumbar stabilization with transpedicular screws. All surgeries were performed by the same surgeon. Patients were divided into two groups. In the group 1 (n = 104), implants were bathed in a solution of local prophylactic antibiotics for 5 seconds just before implantation. In the group 2 (n = 135), implants were not bathed before implantation. Local antibiotics used in the study was effective against gram positive bacteria (including methicillin resistant Staphylococcus aureus) and gram negative bacteria. The rate of surgical site infection and wound healing time were compared between the groups.

RESULTS

A total of 10 patients (4.1%) had deep wound infection and 20 (8.4%) had superficial infection. The most common bacteria was Staphylococcus aureus. One patient died 21 days after the surgery because of sepsis. The wound healed in a mean of 9.66 ± 2.04 days in patients who had no infection and in 32.33 ± 19.64 days in patients with infection (p < 0.001). The patients in group 1 had significantly less deep infection than the patients in group 2 (p < 0.05). However, there was no statistically significant difference between the groups for superficial infection. Patients with vertebral fracture had significantly lower deep infection rate in group 1. The deep infection rate of group 1 patients with diabetes, with bleeding of more than 2000 mL, transfused with blood transfusions above 3 units and with dural injury was significantly lower than those in the group 2. None of the patients had allergic reactions to the drugs used for local prophylaxis.

CONCLUSIONS

This study shown that bathing implants in antibiotics solution was an effective local prophylactic method to prevent deep infections in spinal surgeries with instrumentation.

LEVEL OF EVIDENCE

Level III, Therapeutic study.

Revision spine surgery in patients without clinical signs of infection: How often are there occult infections in removed hardware?

PURPOSE

To examine the incidence of occult infection in revision spine surgeries and its correlation with preoperative inflammatory markers.

METHODS

We retrospectively reviewed all patients who underwent revision spine surgery and hardware removal between 2010 and 2016. Patients who had preoperative clinical signs of infection were excluded. The hardware and surrounding tissue culture results were obtained. The patients' diagnosis and preoperative inflammatory marker (ESR, CRP, and procalcitonin) levels were recorded.

RESULTS

A total of 162 consecutive patients were included in this study. The patients' mean age was 61 years (range 14-88). One hundred and three patients (63.6%) were female. Seventy-two patients (44.4%) had loose hardware and 88 patients (54.3%) had pseudarthrosis. Postoperatively, the hardware and/or surrounding tissue culture was positive in 15 patients (9.3%). The most commonly identified organisms were Propionibacterium acnes (7/15, 46.7%) and Staphylococcus (6/15, 40.0%). The other identified organisms were Pseudomonas aeruginosa (1/15, 6.7%) and Serratia marcescens (1/15, 6.7%). Only four patients with positive cultures had elevated preoperative ESR and CRP levels. Only two patients with positive cultures had elevated preoperative procalcitonin levels. There is no correlation between the patients' preoperative ESR, CRP, procalcitonin levels, and positive culture results (p > 0.05).

CONCLUSIONS

Our study shows that occult infections are present in 9.3% of patients who underwent revision spine surgery and hardware removal although they did not have clinical signs of infection. Those commonly used preoperative inflammatory markers such as ESR, CRP, and procalcitonin may not be sensitive enough to detect occult infections in these patients. These slides can be retrieved under Electronic Supplementary Material.

Complications associated with intrathecal morphine in spine surgery: a retrospective study

Background

Supplemental intrathecal morphine (ITM) represents an option to manage postoperative pain after spine surgery due to ease of administration and ability to confer effective short-term analgesia at low dosages. However, whether ITM increases risk of surgical site infections (SSI), cerebrospinal fluid (CSF) leak, and incidental dural tears (IDT) has not been investigated. Therefore, this study was performed to determine the rates of SSI, CSF leak, and IDT in patients that received ITM.

Methods

Patients that underwent posterior instrumented fusion from January 2010 to 2016 that received ITM were compared to controls with respect to demographic, medical, surgical, and outcome data. Fisher's exact test was used to compare rates of SSI, CSF leak, and IDT between groups. Poisson regression was used to analyze complication rates after adjusting for the influence of covariates and potential confounders.

Results

A total of 512 records were analyzed. ITM was administered to 78 patients prior to wound closure. The remaining 434 patients compromised the control group. IDT was significantly more common among patients receiving ITM (P=0.009). Differences in rates of CSF leak and SSI were not statistically significant (P=0.373 and P=0.564, respectively). After compensating for additional variables, Poisson regression revealed a significant increase in rates of IDT (P=0.007) according to ITM injection and advanced age (P=0.014). There was no significant difference in rates of CSF leak or SSI after accounting for the additional variables (P>0.05).

Conclusions

ITM for pain control in posterior instrumented spinal fusion surgery was linked to increased likelihood of IDT but not CSF leaks or SSI. Age was also noted to be a significant predictor of IDT. Spine surgeons should weigh potential risks against benefits when deciding whether to administer ITM for postoperative pain management following spine surgery.

Retrospective analysis of culture-negative versus culture-positive postoperative spinal infections

Retrospective analysis.This study aimed to investigate the characteristics, clinical features, and outcomes of culture-negative (CN) and culture-positive (CP) postoperative spinal infections (PSIs).Causative organism cultures and the use of adequate antibiotics are essential for treating postoperative spinal wound infections. However, managing infected surgical sites with negative wound culture results is a common clinical problem. Although the outcomes of microbiologically confirmed PSIs have been well studied, the outcomes and clinical characteristics of CN PSIs have not been previously published.Between January 1995 and December 2014, 69 patients diagnosed with PSIs were enrolled. Enrolled patients were classified into 2 groups: CN (28 patients) and CP (41 patients). Baseline data, clinical manifestations, specific treatments, and treatment outcomes were compared with the groups.The overall rate of CN PSI was 40.6% (28/69). Baseline data and clinical manifestations were similar between the 2 groups. There were no significant differences in the duration of parenteral antibiotic use between the CN and CP groups. Revision surgery was required less often for the CN group (64.3%) than for the CP group (87.8%) (P = .020). Revision surgeries were repeated 0.82 times/case in the CN group and 1.34 times/case in the CP group (P = .014). Treatment outcomes, such as poor radiologic findings, need for additional anterior surgery, extension of fusion to adjacent segment surgery, and total length of hospital stay, were not different between groups.Revision surgery was performed less often for the CN group than for the CP group. From the perspective of revision surgery, CN PSIs have better prognosis than CP PSIs. However, clinical presentations and radiologic prognoses were not different between the two groups. We suggest that CN PSIs may be treated in the same way as CP PSIs.

Antisepsis of the skin before spinal surgery with povidone iodine-alcohol followed by chlorhexidine gluconate-alcohol versus povidone iodine-alcohol applied twice for the prevention of contamination of the wound by bacteria: a randomised controlled trial

AIMS

The aim of this study was to determine whether the sequential application of povidone iodine-alcohol (PVI) followed by chlorhexidine gluconate-alcohol (CHG) would reduce surgical wound contamination to a greater extent than PVI applied twice in patients undergoing spinal surgery.

PATIENTS AND METHODS

A single-centre, interventional, two arm, parallel group randomised controlled trial was undertaken, involving 407 patients who underwent elective spinal surgery. For 203 patients, the skin was disinfected before surgery using PVI (10% [w/w (1% w/w available iodine)] in 95% industrial denatured alcohol, povidone iodine; Videne Alcoholic Tincture) twice, and for 204 patients using PVI once followed by CHG (2% [w/v] chlorhexidine gluconate in 70% [v/v] isopropyl alcohol; Chloraprep with tint). The primary outcome measure was contamination of the wound determined by aerobic and anaerobic bacterial growth from samples taken after disinfection.

RESULTS

The detection of viable bacteria in any one of the samples taken after disinfection (culture-positive) was significantly lower in the group treated with both PVI and CHG than in the group treated with PVI alone (59 (29.1%) versus 85 (41.7%), p = 0.009; odds ratio 0.574; 95% confidence interval, 0.380 to 0.866).

CONCLUSIONS

Antisepsis of the skin with the sequential application of PVI and CHG more effectively reduces the contamination of a surgical wound than PVI alone. Cite this article: Bone Joint J 2017;99-B:1354-65.

Risk factors of surgical site infections in instrumented spine surgery

BACKGROUND

The incidence of wound infections associated with instrumented spine surgery ranges from 2 to 20%. These complications may lead to poor outcomes. Knowing the risk factors associated with surgical site infections (SSI) after utilizing spinal implants is essential to avoid these complications, including hardware removal.

METHODS

We reviewed retrospectively 550 patients who underwent spinal fusion surgery from 2011 to 2015; 16 developed SSI after spinal instrumentation. The diagnosis of SSI was established based on positive wound swab or blood cultures, and various clinical, laboratory, and radiological findings. Additional preoperative and intraoperative risk factors were analyzed.

RESULTS

The incidence of SSI after spinal instrumentation surgery was 2.9%. Obesity was a statistically significant parameter (P = 0.013) that contributed to SSI along with the alcoholism and/or drug abuse (P = 0.034); use of a Foley catheter nearly reached significance levels.

CONCLUSIONS

There is an increased risk of SSI in patients who are obese or use drugs and/or alcohol. Clear preoperative identification of these risk factors prior to implanting spinal instrumentation should help prevent SSI in the future.

On-demand antibiotic-eluting microchip for implanted spinal screws

OBJECTIVE

Surgical instrumentation of the spine is susceptible to infection. Intravenous antibiotics is a current mainstay of treating infection; however penetrating the bacterial biofilm and directly targeting the source of the infection is challenging.

METHODS

Using multiple reservoirs of discrete drug doses, microchips represent a new technology capable of on-demand drug release over long periods of time.

RESULTS

A novel solution of integrating vancomycin-eluting microchips into pedicle screws in order directly target and treat spinal infections is proposed.

CONCLUSION

This drug-releasing implant has the potential to provide the particular benefit to high-infection-risk patients in order to avoid reoperation.

Deep spinal infection in instrumented spinal surgery: diagnostic factors and therapy

AIM

Postoperative surgical site infections (SSI) are complication of spinal surgery. These complications may lead to a poor outcome with neurological deficits, spinal deformity and chronic pain. The purpose of this study is to explore the statistical value of diagnostic parameters and the proper therapy.

METHOD

We retrospectively reviewed 550 patients who underwent spinal instrumentation at our department from January 2011 to December 2015. The SSI was present in 16 patients out of 550 operated. Diagnostic criteria of SSI were the positivity of the surgical wound swab or blood culture, the clinical findings, positivity of laboratory tests and radiological elements. All patients had peri-operative antibiotic prophylaxis. Diagnostic laboratory findings were compared with a homogeneous control group of 16 patients and analyzed by univariate statistical analysis with Chi-square test for the discrete variables. P<0,05 was considered statistically significant.

RESULTS

Matching the SSI patients with a group of control, fever was not statistically significant for diagnosis as number of leukocytes, neutrophils and lymphocytes. On the contrary values of ESR and CRP were statistically significant with p <0, 01. The hardware was removed only in 3 patients (18%) out of 16 SSI patients.

CONCLUSION

In this study the statistically significant parameters to diagnose SSI are ESR and CRP values. The leucocytes count, number of lymphocytes and presence of fever integrates the data of ESR and CRP with no statistical significance. Most patients with SSI reach clinical healing with favorable outcome by means of target antibiotic therapy without hardware removal.

Antimicrobial Prophylaxis in Instrumented Spinal Fusion Surgery: A Comparative Analysis of 24-Hour and 72-Hour Dosages

Study Design

Prospective study.

Purpose

To compare the efficacy of 24-hour and 72-hour antibiotic prophylaxis in preventing surgical site infections (SSIs).

Overview of Literature

Antimicrobial prophylaxis in surgical practice has become a universally accepted protocol for minimizing postoperative complications related to infections. Although prophylaxis is an accepted practice, a debate exists with regard to the antibiotic type and its administration duration for various surgical procedures.

Methods

Our institute is a tertiary care hospital with more than 100 spinal surgeries per year for various spine disorders in the department of orthopedics. We conducted this prospective study in our department from June 2012 to January 2015. A total of 326 patients were enrolled in this study, with 156 patients in the 72-hour antibiotic prophylaxis group (group A) and 170 patients in the 24-hour group (group B). Cefazolin was the antibiotic used in both groups. Two surgeons were involved in conducting all the spinal procedures. Our study compared SSIs among patients undergoing instrumented spinal fusion.

Results

The overall rate of SSIs was 1.8% with no statistical difference between the two groups.

Conclusions

The 24-hour antimicrobial prophylaxis is as effective as the 72-hour dosage in instrumented spinal fusion surgery.

Burden of Surgical Site Infections Associated with Select Spine Operations and Involvement of Staphylococcus aureus

BACKGROUND

Spine operations may be indicated for treatment of diseases including vertebral injuries, degenerative spinal conditions, disk disease, spinal misalignments, or malformations. Surgical site infection (SSI) is a clinically important complication of spine surgery. Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA), is a leading cause of post-spinal SSIs.

METHODS

PubMed and applicable infectious disease conference proceedings were searched to identify relevant published studies. Overall, 343 full-text publications were screened for epidemiologic, mortality, health care resource utilization, and cost data on SSIs associated with specified spine operations.

RESULTS

Surgical site infection rates were identified in 161 studies from North America, Europe, and Asia. Pooled average SSI and S. aureus SSI rates for spine surgery were 1.9% (median, 3.3%; range, 0.1%-22.6%) and 1.0% (median, 2.0%; range, 0.02%-10.0%). Pooled average contribution of S. aureus infections to spinal SSIs was 49.3% (median, 50.0%; range, 16.7%-100%). Pooled average proportion of S. aureus SSIs attributable to MRSA was 37.9% (median, 42.5%; range, 0%-100%). Instrumented spinal fusion had the highest pooled average SSI rate (3.8%), followed by spinal decompression (1.8%) and spinal fusion (1.6%). The SSI-related mortality rate among spine surgical patients ranged from 1.1%-2.3% (three studies). All studies comparing SSI and control cohorts reported longer hospital stays for patients with SSIs. Pooled average SSI-associated re-admission rate occurring within 30 d from discharge ranged from 20% to 100% (four studies). Pooled average SSI-related re-operation rate was 67.1% (median, 100%; range, 33.5%-100%). According to two studies reporting direct costs, spine surgical patients incur approximately double the health care costs when they develop an SSI.

CONCLUSIONS

Available published studies demonstrate a clinically important burden of SSIs related to spine operations and the substantial contribution of S. aureus (including MRSA). Preventive strategies aimed specifically at S. aureus SSIs could reduce health care costs and improve patient outcomes for spine operations.

Clinical Characteristics and Outcomes Among Individuals With Spinal Implant Infections: A Descriptive Study

Little is known about the clinical presentation and outcomes associated with spinal implant infections. Here, we describe a single center's experience in a retrospective cohort of 109 individuals with spinal implant infections, including clinical, microbiological, therapeutic, and outcome data.

[Postoperative spinal column]

STANDARD PROCEDURE

As a rule, postoperative imaging is carried out after spinal interventions to document the exact position of the implant material.

INFORMATION

Imaging is absolutely necessary when new clinical symptoms occur postoperatively. In this case a rebleeding or an incorrect implant position abutting a root or the spinal cord must be proven. In addition to these immediately occurring postoperative clinical symptoms, there are a number of complications that can occur several days, weeks or even months later. These include the failed back surgery syndrome, implant loosening or breakage of the material and relapse of a disc herniation and spondylodiscitis.

REVIEW

In addition to knowledge of the original clinical symptoms, it is also important to know the operation details, such as the access route and the material used.

RECOMMENDATION

In almost all postoperative cases, imaging with contrast medium administration and corresponding correction of artefacts by the implant material, such as the dual energy technique, correction algorithms and the use of special magnetic resonance (MR) sequences are necessary.

RECOMMENDATION

In order to correctly assess the postoperative imaging, knowledge of the surgical procedure and the previous clinical symptoms are mandatory besides special computed tomography (CT) techniques and MR sequences.

Microbiologic profile of infections in presumed aseptic revision spine surgery

PURPOSE

Intra-operative cultures may be obtained in revision spine surgery despite the absence of pre-operative clinical markers of infection. The microbiologic profile of culture positive cases in which there is no clear evidence of infection preoperatively has not been described. The aim of this investigation is to report on the microbiologic profile of unexpected culture positive revision spine surgery cases.

METHODS

We retrospectively reviewed 595 consecutive revision spine surgeries performed between 2008 and 2013. Five hundred and seventy-eight revision surgeries were performed for diagnoses other than infection and were included in the study.

RESULTS

Operative cultures were obtained in 112 cases (19.4 %). Cultures were positive in 45 cases. Pseudarthrosis was not only the most common diagnosis overall (49.1 %) in which intra-operative cultures were obtained, it was also the most common revision surgical diagnosis where cultures were positive (55.6 %). Propionibacterium acnes was cultured in 54.2 % of cases with the primary diagnosis of pseudarthrosis, but only in 40.9 % of cases with other diagnoses (P = 0.554). Overall, staphylococcal species were found most commonly (57.8 % of cases), but P. acnes was at least one of the isolates in 48.9 % of cases and was three times more common than any other organism.

CONCLUSIONS

Nearly one in five patients with the diagnosis of pseudarthrosis were culture positive. More specifically, pseudarthrosis was the most common culture positive diagnosis and P. acnes species predominated in this patient population. Propionibacterium acnes was overwhelmingly the most common single organism cultured in revision spine surgery. Given this, we recommend all cultures be held for P. acnes, particularly in the setting of pseudarthrosis.

Multiple recurrent postoperative spinal infections due to an unrecognized presacral abscess following placement of bicortical sacral screws: case report

Postoperative wound infections in spinal surgery remain an important complication to diagnose and treat successfully. In most cases of deep infection, even with instrumentation, aggressive soft-tissue debridement followed by intravenous antibiotics is sufficient. This report presents a patient who underwent L3-S1 laminectomy and pedicle screw placement including bicortical sacral screws. This patient went on to develop multiple (7) recurrent infections at the operative site over a 5-year period. Continued investigation eventually revealed a large presacral abscess, which remained the source of recurrent bacterial seeding via the remaining bone tracts of the bicortical sacral screws placed during the original lumbar surgery. Two years after drainage of this presacral collection via a retroperitoneal approach, the patient remains symptom free.

Safety of instrumentation and fusion at the time of surgical debridement for spinal infection

The present study aims to assess the results of single-stage instrumentation and fusion at the time of surgical debridement of spinal infections; vertebral osteomyelitis or epidural abscess. Nine patients with spinal infection were treated with instrumentation and fusion after radical debridement in a single-stage operation. Predisposing factors and comorbidities, pain, American Spinal Injury Association motor scores, primary pathologies, microbiology and perioperative markers were recorded. Seven patients with pyogenic and two with tuberculous spinal infection were encountered; the most common pathogen was Staphylococcus aureus. Five patients were predisposed to infection because of diabetes mellitus. Duration of antibiotic therapy lasted up to 12 months. Six patients had thoracic infection, two lumbar and one cervical. No post-operative complications were encountered. There was a significant reduction in pain scores compared to pre-operatively. All patients with neurological deficits improved post-operatively. Despite introduction of hardware, no patients had a recurrence of their infection in the 12 month follow up period. Single-stage debridement and instrumentation appeared to be a safe and effective method of managing spinal infections. The combination of debridement and fusion has the dual benefit of removing a focus of infection and stabilising the spine. The current series confirms that placing titanium cages into an infected space is safe in a majority of patients. Stabilisation and correction of spinal deformity reduces pain, aids neurologic recovery and improves quality of life. The small patient population and retrospective nature limit the present study.

[Postoperative spine]

Approximately 15-30 % of surgical procedures involving the lumbar spine are associated with complications that require further diagnostic work-up. The choice of imaging modality for postoperative complications depends on the extent, pattern and temporal evolution of the postoperative neurological signs and symptoms as well as on the preoperative clinical status, the surgical procedure itself and the underlying pathology. The interpretation of imaging findings, in particular the distinction between postoperative complications and normally expected nonspecific postoperative imaging alterations can be challenging and requires the integration of clinical neurological information and the results of laboratory tests. The combination of different imaging techniques might help in cases of equivocal imaging results.

Entero-paraspinous fistula from recurrent spinal metastatic renal cell carcinoma

The authors report a case of entero-paraspinous fistula 2 years after T-12 corpectomy and instrumentation for spinal metastasis from renal cell carcinoma. The pathogenesis in the present case seems to have arisen from local recurrence of T-12 metastatic carcinoma in spite of radiation and corpectomy. As a result of previous nephrectomy and anterolateral dissection for the T-12 corpectomy, the jejunum adhered to the surgical site. Recurrent tumor at T-12 invaded the adherent small bowel loop, resulting in a fistulous communication between the small bowel lumen and the spinal wound. Loss of retroperitoneal fat, scarring, and adhesions from previous surgeries contributed to this complication by having the jejunum close to the T-12 corpectomy site, and eventually to its invasion by recurrent tumor. Avoidance of such a complication is difficult; however, total excision of the spinal malignancy, and when possible, creating a barrier cuff of fascia or fat around the spine to protect abdominal contents, are potential solutions.