Evaluation of (111) Indium-Labeled Autologous Leukocyte Scintigraphy for the Diagnosis of Chronic Osteomyelitis in Patients With Grade IV Pressure Ulcers, as Compared With a Standard Diagnostic Protocol

Imaging tests for the detection of osteomyelitis: a systematic review

BACKGROUND

Osteomyelitis is an infection of the bone. Medical imaging tests, such as radiography, ultrasound, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and positron emission tomography (PET), are often used to diagnose osteomyelitis.

OBJECTIVES

To systematically review the evidence on the diagnostic accuracy, inter-rater reliability and implementation of imaging tests to diagnose osteomyelitis.

DATA SOURCES

We conducted a systematic review of imaging tests to diagnose osteomyelitis. We searched MEDLINE and other databases from inception to July 2018.

REVIEW METHODS

Risk of bias was assessed with QUADAS-2 [quality assessment of diagnostic accuracy studies (version 2)]. Diagnostic accuracy was assessed using bivariate regression models. Imaging tests were compared. Subgroup analyses were performed based on the location and nature of the suspected osteomyelitis. Studies of children, inter-rater reliability and implementation outcomes were synthesised narratively.

RESULTS

Eighty-one studies were included (diagnostic accuracy: 77 studies; inter-rater reliability: 11 studies; implementation: one study; some studies were included in two reviews). One-quarter of diagnostic accuracy studies were rated as being at a high risk of bias. In adults, MRI had high diagnostic accuracy [95.6% sensitivity, 95% confidence interval (CI) 92.4% to 97.5%; 80.7% specificity, 95% CI 70.8% to 87.8%]. PET also had high accuracy (85.1% sensitivity, 95% CI 71.5% to 92.9%; 92.8% specificity, 95% CI 83.0% to 97.1%), as did SPECT (95.1% sensitivity, 95% CI 87.8% to 98.1%; 82.0% specificity, 95% CI 61.5% to 92.8%). There was similar diagnostic performance with MRI, PET and SPECT. Scintigraphy (83.6% sensitivity, 95% CI 71.8% to 91.1%; 70.6% specificity, 57.7% to 80.8%), computed tomography (69.7% sensitivity, 95% CI 40.1% to 88.7%; 90.2% specificity, 95% CI 57.6% to 98.4%) and radiography (70.4% sensitivity, 95% CI 61.6% to 77.8%; 81.5% specificity, 95% CI 69.6% to 89.5%) all had generally inferior diagnostic accuracy. Technetium-99m hexamethylpropyleneamine oxime white blood cell scintigraphy (87.3% sensitivity, 95% CI 75.1% to 94.0%; 94.7% specificity, 95% CI 84.9% to 98.3%) had higher diagnostic accuracy, similar to that of PET or MRI. There was no evidence that diagnostic accuracy varied by scan location or cause of osteomyelitis, although data on many scan locations were limited. Diagnostic accuracy in diabetic foot patients was similar to the overall results. Only three studies in children were identified; results were too limited to draw any conclusions. Eleven studies evaluated inter-rater reliability. MRI had acceptable inter-rater reliability. We found only one study on test implementation and no evidence on patient preferences or cost-effectiveness of imaging tests for osteomyelitis.

LIMITATIONS

Most studies included < 50 participants and were poorly reported. There was limited evidence for children, ultrasonography and on clinical factors other than diagnostic accuracy.

CONCLUSIONS

Osteomyelitis is reliably diagnosed by MRI, PET and SPECT. No clear reason to prefer one test over the other in terms of diagnostic accuracy was identified. The wider availability of MRI machines, and the fact that MRI does not expose patients to harmful ionising radiation, may mean that MRI is preferable in most cases. Diagnostic accuracy does not appear to vary with the potential cause of osteomyelitis or with the body part scanned. Considerable uncertainty remains over the diagnostic accuracy of imaging tests in children. Studies of diagnostic accuracy in children, particularly using MRI and ultrasound, are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017068511.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 61. See the NIHR Journals Library website for further project information.

Diagnosing pelvic osteomyelitis in patients with pressure ulcers: a systematic review comparing bone histology with alternative diagnostic modalities

Accurate diagnosis of osteomyelitis underlying pressure ulcers is essential, as overdiagnosis exposes patients to unnecessary and prolonged antibiotic therapy, while failure to diagnose prevents successful treatment. Histopathological examination of bone biopsy specimens is the diagnostic gold standard. Bone biopsy can be an invasive procedure, and, for this reason, other diagnostic modalities are commonly used. However, their accuracy is questioned in literature. This systematic review aims to assess accuracy of various modalities (clinical, microbiological and radiological) for the diagnosis of pelvic osteomyelitis in patients with pressure ulcers as compared to the gold standard. A systematic literature search was conducted in July 2019 using the MEDLINE (Medical Literature Analysis and Retrieval System - MEDLARS - Online) and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases. The search terms were "decubitus ulcer", "pressure ulcer", "pressure sore", "bedsore" and "osteomyelitis". The inclusion criteria were original full-text articles in English comparing the results of bone histology with those of other diagnostic modalities in adult patients with pelvic pressure ulcers. Six articles were included in the systematic review. Clinical diagnosis was found to be neither specific nor sensitive. Microbiological examination, and in particular cultures of bone biopsy specimens, displayed high sensitivity but low specificity, likely reflecting contamination. Radiological imaging in the form of X-ray and CT (computed tomography) scans displayed high specificity but low sensitivity. MRI (magnetic resonance imaging), bone scanning and indium-labelled scintigraphy displayed high sensitivity but low specificity. Our systematic review did not find any diagnostic method (clinical, microbiological or radiological) to be reliable in the diagnosis of pelvic osteomyelitis associated with pressure ulcers as compared to bone histology.

The ideal dual-isotope imaging combination in evaluating patients with suspected infection of pelvic pressure ulcers

INTRODUCTION

The successful management of infected pelvic pressure ulcer patients (PPUP) depends on the distinction between infections limited to soft tissue (STI) and those with underlying osteomyelitis (OM), which can be difficult to determine clinically. Dual-isotope (DI) comprehensive imaging has excellent accuracy in localizing diabetic foot infection and differentiating OM from STI with SPECT/CT utilization. In this study, we assess the accuracy and confidence of the different DI SPECT/CT imaging steps in PPUP with confirmed diagnoses.

PATIENTS AND METHODS

Pelvic flow and blood pool imaging were followed by labeled white blood cell reinjection and Tc-99m hydroxymethylene-diphosphonate bone (bone scan) and In-111-leukocytes (white blood cell scan) DI planar and SPECT/CT (step 1) acquisitions. Tc-99m sulfur colloid (bone marrow scan)/WBCS SPECT/CT (step 2) images were obtained on the following day. DI step 1 planar, step 1 SPECT/CT, step 2 SPECT/CT, and combined step 1/step 2 SPECT/CT were reviewed separately for diagnosis and diagnosis confidence. The final diagnosis was confirmed by culture/pathology in 21 patients and clinical/imaging follow-up in 12 patients.

RESULTS

There were 19 OM patients, three STI patients, and 11 patients with no infection. The final diagnosis agreement to DI combined step 1/step 2 SPECT/CT was higher than DI step 2 or step 1 SPECT/CT alone, or DI step 1 planar, as assessed by λ and error reduction %, respectively. Combined DI step 1/step 2 SPECT/CT was more sensitive than DI step 2 SPECT/CT and more specific than DI step 1 SPECT/CT, and showed higher diagnostic confidence than both imaging techniques.

CONCLUSION

DI SPECT/CT is highly useful in evaluating PPUP with suspected infection. DI step 1 is more sensitive, whereas step 2 is more specific. Both step 1 and step 2 DI SPECT/CT images are needed to accurately and confidently assess for infection and distinguish OM from STI, which are crucial for optimal management.

Two-stage treatment of ischial pressure ulcers in spinal cord injury patients: Technique and outcomes over 8 years

BACKGROUND

Despite newly introduced techniques, reconstruction of ischial pressure ulcers remains a difficult problem with high-reported failure rates.

METHODS

A retrospective chart review was performed on all spinal cord injury patients who underwent ischial pressure ulcer reconstruction by the senior author (V.L.) between 2004 and 2012. The two-stage procedure consisted of debridement and bone biopsy, followed by bursectomy, partial ischiectomy, fascial release, and gluteus maximus and hamstring advancement flaps. Postoperative care included 2-week supine bed rest on an air-fluidized bed, sitting tolerance rehabilitation, and thorough behavioral training.

RESULTS

Sixty-five patients (74 flaps) were identified. A 45.9% had a previous attempt at reconstruction. The median follow-up period was 622 days. Overall, 67.6% of flaps were intact at the last follow-up. Superficial and deep dehiscence rates were 16.2 and 28.4%, respectively. Seven out of 35 flaps suffered late recurrence after being well healed for more than 1 year. History of previous reconstruction was found to be associated with increased odds of superficial (OR 6.02, 95% CI 1.55-23.3) and deep dehiscence (OR 12.3, 95% CI 1.99-76.9).

CONCLUSIONS

The evolution of the senior author's decades of practice has led to the development of a simpler repair, which relies on plane-by-plane release of scarred tissues to improve the mobility of muscle and skin flaps without large tissue movements, even in the setting of apparent extensive tissue loss. This technique is a reliable option, particularly for the primary ischial pressure ulcer.

Critically evaluating the role of diagnostic imaging in osteomyelitis

Early diagnosis, essential for timely appropriate treatment and reduction of complications, can be difficult. This article aims to give an overview of the role that different imaging modalities have to play in the diagnosis of osteomyelitis. Osteomyelitis is a heterogeneous disease in its pathophysiology, clinical presentation, and management. It infers inflammation of bone and marrow, whereas osteitis is inflammation of the bone only. Thus, a soft-tissue infection that reaches the bone surface but has not infected the marrow is osteitis and not osteomyelitis. Chronic osteomyelitis is divided into active and inactive forms. Newly appearing periosteal reaction or bone destruction within the chronic involucrum are indicators of activation. Imaging modalities represent different underlying pathophysiological processes that may be represented in differing types and differing phases of osteomyelitis. Sequential selection of appropriate imaging modalities requires a thorough understanding of the disease processes and the process by which each modality visualizes this dynamic disease process.

Successful truncated osteomyelitis treatment for chronic osteomyelitis secondary to pressure ulcers in spinal cord injury patients

Time-tested treatments for chronic osteomyelitis involve prolonged courses of costly antibiotic treatment. Although such treatment remains unquestioned in acute osteomyelitis, it is an excessive regiment for chronic osteomyelitis. With appropriate surgical debridement and careful operative care, antibiotic treatment can be truncated in diagnoses of chronic osteomyelitis. This study represents the clinical practice of the pressure ulcer management program at Rancho Los Amigos National Rehabilitation Center in dealing with this difficult problem. One hundred fifty-seven patients with similar pressure ulcer wounds were studied retrospectively. Three groups of patients with pathologic diagnoses of acute osteomyelitis, chronic osteomyelitis, and negative osteomyelitis were compared for (1) postoperative stay, (2) wound infection, (3) wound breakdown requiring reoperation, and (4) same-site ulcer recurrence. In all cases, shallow bone shavings were sent for diagnosis via histologic study, and deep shavings were also sent to ensure adequate bone debridement and microbiologic study. All ulcers were subsequently closed with muscle and/or myocutaneous flaps. The negative and chronic osteomyelitis groups were treated with 5 to 7 days of IV antibiotics, whereas the acute group underwent a full 6-week course according to bone bacteriological culture and sensitivity. There was no statistical difference between the chronic osteomyelitis group and the control (negative) osteomyelitis group with respect to postoperative stay (70 days for chronic group, 72.4 for control), wound breakdown rate (10.7% for chronic, 10.2% for control), or ulcer recurrence (1.8% for chronic, 4.1 for control). The acute osteomyelitis group incurred longer hospital stays, greater incidence of wound breakdown, and statistically significantly greater ulcer recurrence (78.6 days, 13.2% and 17.0%, respectively). In cases of pressure ulcer management with bony involvement, bone pathologic diagnosis of chronic osteomyelitis allows for a shorter antibiotic course with better results when the offending tissue has been adequately debrided and closed with viable tissue flap coverage, than simple long-term (4-6 weeks) antibiotic treatment. Because of the extreme contaminated nature of these wounds, if such therapy works in these patients, it may be applicable to chronic osteomyelitis in more varied contaminated surgical cases involving bone.