Vascularized Bone Grafts for Spinal Fusion—Part 1: The Iliac Crest

BACKGROUND Iliac crest autograft has been the gold standard for harvest of fusion materials in spine surgery. The benefits of a vascularized version of this bone graft—including delivery of stem cells, ability to deliver antibiotics to the fusion bed, and relative ease of harvest—make this technique superior to free bone transfer in the achievement of augmented spinal fusion. OBJECTIVE To present a brief summary of similar existing concepts before describing the novel technique of this vascularized posterior iliac crest bone graft. METHODS Vascularized posterior iliac crest bone graft can be harvested from the same midline lumbar incision used for thoracolumbar spinal fusion, through lateral dissection around the paraspinals to the iliac crest. Recipient sites in the posterolateral bony spinal gutters may be as rostral as T12 and caudal as the sacrum. The ability to cover multiple lumbar levels can be achieved with desired lengths of the donor iliac crest. RESULTS Over 14 vascularized iliac crest bone grafts have been performed to augment lumbar fusion for salvage after pseudoarthrosis. Operative time and bleeding are reduced compared to free flap procedures, and no patients have experienced any complications related to these grafts. Indocyanine green (ICG) angiography has been utilized in a novel way to ensure the vascularity of the bone graft prior to arthrodesis. CONCLUSION While long-term follow-up will be required to fully characterize fusion rates and patient morbidity, this innovative surgical option augments spinal fusion in patients with, or at increased risk for, pseudoarthrosis.

Vascularized Posterior Iliac Crest Bone Grafting: Indications, Techniques, Clinical Outcomes, and Alternatives

Pseudarthrosis is a feared complication of spinal fusion procedures. Currently, the gold standard in prevention or treatment of pseudarthrosis is placement of nonvascularized iliac crest bone autograft. While rates of fusion are significantly higher in patients with use of nonvascularized bone autografts than with allografts, patients who have previously failed lumbar arthrodesis or those at a high risk for pseudarthrosis may benefit from a more robust, vascularized bone graft with enhanced osteogenicity. In this article, we discuss the use of iliac crest vascularized bone grafts as an adjunct for high-risk patients undergoing lumbosacral spine arthrodesis.

Maximizing FDG-PET/CT Utility in Staging of Follicular Lymphoma (FL): The Role of Spleen Involvement and Bone Standardized Uptake Values

Background: FDG PET/CT and bone marrow biopsy (BMB) are considered standard procedures for the staging of patients with new, untreated FL. A key issue in FL is the early identification of patients who will fail early. We recently reported (Am J Hematology 2019) that the presence of ≥2 EN sites, spleen, bone or soft tissue involvement as detected by PET all predicted failure to achieve EFS24. In Hodgkin lymphoma and diffuse large B-cell NHL, PET has replaced the routine need for a staging BMB. However, there is no such evidence in FL. The goal of this study was to determine the value of FDG PET/CT in determining bone involvement in FL using BMB as the gold standard. Methods: Patients were identified using the Mayo Clinic Lymphoma Database. 548 patients with newly diagnosed FL grades 1-3A between years 2003-2016, available BMB results, and PET/CT imaging at diagnosis, were included in the analysis. The presence of bone and spleen involvement on PET/CT, SUVmax and SUVmean of the axial skeleton at L3, and BMB results were recorded and compared. Results: In all, 36% (197/548) of patients had a positive BMB, and 34% (189/548) had bone involvement detected on PET/CT. Compared to BMB, the sensitivity and specificity of PET/CT in detecting bone involvement as determined by BMB were 60% and 80%, respectively. We noted that 59 patients had focal bone involvement on PET/CT rather than a diffuse component, and found that 47% (28/59) of these patients had a negative BMB obtained in the posterior iliac crest. Excluding these patients, the sensitivity and specificity of PET/CT in detecting bone involvement were 53% and 88%, respectively (Table 1). With respect to the spleen, 29% (157/548) of patients had evidence of splenic FL involvement on PET/CT, and of these, 69% (109/157) also had a positive BMB. The sensitivity and specificity of spleen involvement on PET/CT in predicting bone involvement on BMB were 55% and 86%, respectively (Table 2). We recorded SUV data at L3 in the 439 patients who had either a diffuse pattern of bone involvement on PET/CT, or a PET/CT read as negative. We analyzed the positive and negative predictive values (PPV and NPV) of SUVmax and SUVmean at several cut-off points to determine whether axial bone SUV is reliable at determining patients with a positive or negative BMB. The NPV for an SUVmax of less than 2.0 was 96% (n=25 patients classified as negative). For SUVmean, the best cut-off point was at less than 1.4, where NPV was 100% (n=15 patients classified as negative). There was no logical cut-off point for a significant PPV > 95%. Conclusion: In newly diagnosed FL, the sensitivity and specificity of bone involvement on PET/CT are insufficient for PET/CT to routinely replace BMB. However, in patients where the need for BMB at staging is being debated, certain factors on PET/CT can help facilitate this decision. The detection of focal bone lesions, especially those that may be missed on posterior iliac crest BMB, can make BMB unnecessary. If both the spleen and bone appear involved on PET/CT, this confers a relatively high chance that BMB will be positive. If SUVmax at L3 is less than 2.0, or if SUVmean is less than 1.4, the BMB will likely be negative, with a NPV > 95%. This decision-making algorithm is outlined in Figure 1 and may serve as a useful guideline for clinical trials and routine practice. Disclosures No relevant conflicts of interest to declare.

Safety Profile of Bone Marrow Aspiration and Biopsies Performed By the Hospitalist Procedure Service at an Academic Center: An Observational Study

Background: Bone marrow sampling is an invasive procedure that can be obtained by aspiration and biopsy(also called trephine biopsy) and as such, requires good technical skills to avoid complications and increase diagnostic yield. Aspirate and biopsy samples are complementary and when obtained together, are an invaluable tool toward obtaining an accurate and comprehensive profile for cellular, cytogenetic, immunophenotypic and cytological assessments. Bone marrow aspiration and trephine biopsy are generally regarded as relatively low risk procedures, however, factors that should be taken into consideration include disseminated intravascular coagulopathy, factor deficiencies, skin infections, and severe thrombocytopenia. In adults, the posterior iliac crest is often the preferred site but other accessed sites include the sternum (aspiration only) and anterior superior iliac crest in obese patients.For procedures performed at the posterior iliac spine, possible complications include pain, bleeding and infection. The hospitalist procedure service is a relatively newer advent that make up a subset of hospital medicine practice, mostly in larger academic centers. They are made up of internal medicine faculty with additional procedural training and expertise in bedside procedural care. Depending on the institution, the service performs a variety of procedures with lumbar punctures, thoracentesis and paracentesis, comprising a bulk of them. Other services include bone marrow sampling, arthrocentesis and chest tube placement. The long term impact of procedure services on inpatient hospital teams continues to be an ongoing area of research, but so far, studies have shown that these services have been associated with an increase in best practice safety process measures, increased patient satisfaction, and faster access to procedures without increasing complication rates. At our institution, this procedure is performed by hematology/oncology staff and fellows and advanced practice providers (APP) in collaboration and with direct supervision by an attending physician. Direct supervision is usually unnecessary once competency is determined. Other services qualified to provide this service at our institution include the inpatient hospitalist bedside procedure service (HBPS) and interventional radiology (particularly if needed under computed tomography (CT) guidance). Other than those performed by hematology/oncology providers, the HBPS at our institution is responsible for the majority of bone marrow aspiration and biopsies performed at the bedside. Methods: We reviewed procedure records kept by the inpatient HBPS from February 2017 through May 2019. Most bone marrow sampling were performed on patients on the adult inpatient hematology/oncology service. Other inpatient services represented included Internal Medicine, Physical Medicine and Rehabilitation (PM&R), Cardiology and Transplant (Surgical and Medical). Informed consent was obtained from all patients and/or patient surrogates. All procedures were performed at either the right or left posterior iliac crest using a powered bone marrow biopsy device (Teleflex Arrow On-Control) with an 11 gauge bone access needle, either 4 or 6 inches in length. The site was obtained via landmarks with the patient in either the prone or lateral decubitus position. Specific orders for the procedure were placed by the inpatient clinician/practitioner requesting the procedure. A technician was present at bedside to prepare slides. Results: Of the 233 patients on which bone marrow aspirates and/or biopsies were attempted, 217 (93%) were performed successfully. 16 (7%) were unsuccessful with those patients subsequently referred to interventional radiology for placement under CT guidance. Of the procedures which were successful, 181 (83.4%) were successful with the first attempt, while 36 (16.6%) required more than one attempt. 1 (0.4%) patient experienced a procedural complication secondary to a hematoma. Conclusions: We propose that bone marrow sampling performed by a hospitalist procedure services is a safe and efficacious option and alternative for busy inpatient hematology/oncology services as it can provide faster access to care for patients who need the procedure. It also helps liberate hematology/oncology providers from performing these procedures to allow them the opportunity to focus on patient care and rounds. Disclosures No relevant conflicts of interest to declare.

Diagnosis and investigation in haematology

This chapter addresses the interpretation of the full blood count, blood film, bone marrow examination, and related tests in the diagnosis of haematological disorders. Examination of a stained blood film, which should always be requested if a blood count abnormality cannot readily be explained by the clinical context, may give clues to the cause of the abnormality or prove diagnostic. Examination of the bone marrow is essential to the proper evaluation and diagnosis of many haematological disorders. The simplest form of marrow examination involves needle aspiration of marrow cells from the posterior iliac crest; smears are made and stained in the same way as a blood film. Bone marrow can also be biopsied for histological examination, at the same time as marrow aspiration.