Evaluation of microvascular bone graft reconstruction of the head and neck with 3-D 99mTc-DPD SPECT scans

Facial Reconstruction: A Systematic Review of Current Image Acquisition and Processing Techniques

Introduction: Plastic and reconstructive surgery is based on a culmination of technological advances, diverse techniques, creative adaptations and strategic planning. 3D imaging is a modality that encompasses several of these criteria while encouraging the others. Imaging techniques used in facial imaging come in many different modalities and sub-modalities which is imperative for such a complex area of the body; there is a clear clinical need for hyper-specialized practice. However, with this complexity comes variability and thus there will always be an element of bias in the choices made for imaging techniques. Aims and Objectives: The aim of this review is to systematically analyse the imaging techniques used in facial reconstruction and produce a comprehensive summary and comparison of imaging techniques currently available, including both traditional and novel methods. Methods: The systematic search was performed on EMBASE, PubMed, Scopus, Web of Science and Cochrane reviews using keywords such as "image technique/acquisition/processing," "3-Dimensional," "Facial," and "Reconstruction." The PRISMA guidelines were used to carry out the systematic review. Studies were then subsequently collected and collated; followed by a screening and exclusion process with a final full-text review for further clarification in regard to the selection criteria. A risk of bias assessment was also carried out on each study systematically using the respective tool in relation to the study in question. Results: From the initial 6,147 studies, 75 were deemed to fulfill all selection criteria and selected for meta-analysis. The majority of papers involved the use of computer tomography, though the use of magnetic resonance and handheld scanners using sonography have become more common in the field. The studies ranged in patient population, clinical indication. Seminal papers were highlighted within the group of papers for further analysis. Conclusions: There are clearly many factors that affect the choice of image acquisition techniques and their potential at being ideal for a given role. Ultimately the surgical team's choice will guide much of the decision, but it is crucial to be aware of not just the diagnostic ability of such modalities, but their treatment possibilities as well.

Predicting Vascularized Bone Graft Viability Using 1-Week Postoperative Bone SPECT/CT After Maxillofacial Reconstructive Surgery

Purpose

We aimed to evaluate the performance of hybrid bone single-photon emission computed tomography (SPECT)/computed tomography (CT) in predicting bone graft viability after maxillary or mandibular reconstructive surgery with vascularized bone grafts.

Methods

We retrospectively reviewed 46 bone planar scintigraphy and SPECT/CT images of 45 adult patients taken at 1 week (5-8 days) after maxillary or mandibular reconstructive surgery with vascularized bone grafts. By visual analysis, two nuclear medicine physicians scored the uptake degrees of each bone graft segment compared with the calvarium uptake on planar bone scintigraphy and SPECT/CT, respectively (0 = absence of uptake, 1 = less uptake, 2 = similar uptake, and 3 = more uptake). The imaging results were compared with clinical follow-up for assessing bone graft viability.

Results

During follow-up, five bone graft segments were surgically removed and confirmed as nonviable-one had a score of 0, although the other four had a score of 1-3 on planar bone scintigraphy. All five bone graft segments were scored 0 on SPECT/CT and eventually confirmed as nonviable. All other graft segments with a score of > 1 on SPECT/CT were viable and uneventful. The anatomical CT information on SPECT/CT images was helpful in discriminating bone graft uptake from adjacent bone or soft tissue uptake.

Conclusions

The absence of tracer uptake by the vascularized bone graft on bone SPECT/CT at 1 week after maxillary or mandibular reconstructive surgery can predict graft failure. Bone SPECT/CT can be used to predict vascularized bone graft viability postoperatively.

Outcomes of microvascular bone flaps versus osteocutaneous flaps in head and neck reconstruction

BACKGROUND

Surgical resection of head and neck (H&N) neoplasms requiring osseous reconstruction have underdefined complication profiles. This study aimed to characterize postoperative outcomes of patients with H&N neoplasia undergoing osteocutaneous flap (OCF) or bare bone flap (BBF) reconstructions.

MATERIALS AND METHODS

Retrospective analysis of the National Surgical Quality Improvement Program (NSQIP) 2005-2017 databases. Queried for diagnosis and procedural codes extracted patients with H&N neoplasms undergoing BBF or OCF reconstruction. Postoperative complications were evaluated. Multivariable regression generated adjusted odds ratios.

RESULTS

A cohort of 746 patients were identified. Of reconstructions, 24.9% (n = 186/746) were BBFs while 75.1% (n = 560/746) were OCFs. 58.1% of the BBF cohort and 59.9% of the OCF cohort experienced an all-cause complication (p = .654). Sub-stratified, 24.2% of BBF and 17.5% of OCF patients experienced a wound complication (p = .045). Regression analysis demonstrated no difference in risk for medical complications between cohorts. However, patients receiving OCFs had a decreased likelihood of developing a wound complication (OR 0.652; 95%CI 0.430-0.989; p = .044) compared to patients receiving BBFs.

CONCLUSION

The incidence of complications following osseous reconstruction of the H&N is considerable. Although several complication outcomes do not seem to differ between BBF or OCF reconstructions, OCFs is associated with a decreased likelihood of wound complications.

Determination of structural femoral head allograft viability and integrity with a novel diagnostic tool: SPECT/CT. A preliminary study

OBJECTIVE

To evaluate the viability and integrity of fresh frozen bulk femoral head allografts obtained from the institutional bone bank that were used to reconstruct severe acetabular defects and to validate the SPECT/CT method which gives both anatomical and functional data for this purpose.

METHODS

We retrospectively reviewed 9 patients (6 female, 3 male; mean age 63.6 years). Preoperative and postoperative leg lengths, existence of the Trendelenburg sign, range of motion of the hip, visual analogue score (VAS), Harris Hip Score (HHS) and any complication were assesed at each follow-up. Radiographically, position of the cup, signs of loosening or migration, and union of the graft were all determined. At the latest follow-up, patients were evaluated with hybrid SPECT/CT.

RESULTS

The average duration of follow-up was 38.1 months (24-50 months). The overall mean HHS and VAS scores were significantly improved (p<0.05). When hybrid SPECT/CT results were evaluated, the vascular phase of scintigraphy showed hyperaemia of the graft and the bone phase of scintigraphy showed normal or increased radiotracer uptake in the graft site in 7 patients. SPECT/CT images were used to determine the exact localisation of osteoblastic activity. 1 patient with minor resorption of the graft without clinical symptoms revealed mild osteoblastic activity. The patient who had no activity in the graft site was rerevised because of infection.

CONCLUSIONS

Institutional bank allografts are still excellent options for treating large acetabular defects in revision total hip arthroplasty where trabecular metals are not available or in common use. The Hybrid SPECT/CT method is a reliable, noninvasive method for evaluating both the integrity and viability of a bulk graft in 3-D.

Scintigraphic and histopathologic evaluation of combined bone grafts

OBJECTIVES

We aimed to assess various bone grafts on bone formation using bone scintigraphy and histology, especially the first study that evaluated the demineralized bone matrix (DBM) + tricalcium phosphate (TCP) + hyaluronic acid (HA) combination.

MATERIALS AND METHODS

A total of 44 pieces in groups of autogenous bone graft, TCP, DBM, DBM + TCP combination, and DBM + TCP + HA combination were applied to parietal bones of 24 New Zealand rabbits. Bone scintigraphies of the rabbits were performed at 2, 6, and 12 weeks. The uptake ratios were compared for the different types of grafts. In addition, in 2, 6, and 12 weeks, the graft areas were taken from the sacrificed rabbits and examined histologically.

RESULTS

In the 2-week evaluation, DBM + TCP combination and DBM + TCP + HA combination had more osteoblastic activity accumulation than the TCP and DBM groups. These findings supported that the DBM + TCP combination group showed new bone formation earlier in the histopathological evaluation. The DBM + TCP + HA combination had more uptake than the TCP and DBM groups on bone scintigraphy at 2 weeks, and this uptake ratio decreased in the following weeks. It was thought that the increased uptake in DBM + TCP + HA combination at 2 weeks was due to severe inflammation seen in the histopathological evaluation.

CONCLUSION

The DBM + TCP + HA combination should not be used for graft repair, although it was thought to be a good combination in the early weeks.

Influence of architecture of β-tricalcium phosphate scaffolds on biological performance in repairing segmental bone defects

BACKGROUND

Although three-dimensional (3D) β-tricalcium phosphate (β-TCP) scaffolds serve as promising bone graft substitutes for the segmental bone defect treatment, no consensus has been achieved regarding their optimal 3D architecture.

METHODS

In this study, we has systematically compared four types of β-TCP bone graft substitutes with different 3D architectures, including two types of porous scaffolds, one type of tubular scaffolds and one type of solid scaffolds, for their efficacy in treating segmental bone defect in a rabbit model.

RESULTS

Our study has demonstrated that when compared to the traditional porous and solid scaffolds, tubular scaffolds promoted significantly higher amount of new bone formation in the defect regions as shown by X-ray, micro CT examinations and histological analysis, restored much greater mechanical properties of the damaged bone evidenced by the biomechanical testing, and eventually achieved the complete union of segmental defect. Moreover, the implantation of tubular scaffolds enhanced the neo-vascularization at the defect region with higher bone metabolic activities than others, as indicated by the bone scintigraphy assay.

CONCLUSIONS

This study has further the current knowledge regarding the profound influence of overall 3D architecture of β-TCP scaffolds on their in vivo defect healing performance and illuminated the promising potential use of tubular scaffolds as effective bone graft substitute in treating large segmental bone defects.

The repair of large segmental bone defects in the rabbit with vascularized tissue engineered bone

Management of segmental bone defects is a considerable challenge for orthopedic surgeons. Tissue engineering is a promising method for repairing bone defects, and vascularization is critical to the performance of a tissue engineered bone. We report herein the construction of a vascularized tissue engineered bone with mesenchymal stem cells (MSCs) and MSC-derived endothelial cells (ECs) co-cultured in porous beta-tricalcium phosphate ceramic (beta-TCP) to repair 1.5-cm ulnar defects in the rabbit. Examination by X-ray and single photon emission computed tomography (SPECT), histologic analysis, and biomechanical tests were used to evaluate repair and the vascularization of the implants. The results showed that by co-seeding MSCs and MSC-derived ECs, the resulting vascularization was able to promote osteogenesis and improve mechanical properties. The rabbits treated with vascularized tissue engineered bone exhibited far more extensive osteogenesis and good vascularization. Therefore, we suggest that the vascularized tissue engineered bone constructed by co-culture of MSCs and MSC-derived ECs in porous beta-TCP may be an effective approach to promote repair of segmental bone defects and have potential for repairing large segmental bone defects in a clinical setting.

Early postoperative bone scintigraphy in the evaluation of microvascular bone grafts in head and neck reconstruction

BACKGROUND

Bone scintigraphy was performed to monitor anastomotic patency and bone viability.

METHODS

In this retrospective study, bone scans were carried out during the first three postoperative days in a series of 60 patients who underwent microvascular bone grafting for reconstruction of the mandible or maxilla.

RESULTS

In our series, early bone scans detected a compromised vascular supply to the bone with high accuracy (p < 10-6) and a sensitivity that was superior to the sensitivity of clinical monitoring (92% and 75% respectively).

CONCLUSION

When performing bone scintigraphy during the first three postoperative days, it not only helps to detect complications with high accuracy, as described in earlier studies, but it is also an additional reliable monitoring tool to decide whether or not microvascular revision surgery should be performed. Bone scans were especially useful in buried free flaps where early postoperative monitoring depended exclusively on scans. According to our experience, we recommend bone scans as soon as possible after surgery and immediately in cases suspicious of vascularized bone graft failure.

Role of radionuclide imaging in the orthopedic patient

Since its introduction more than 40 years ago, nuclear medicine has played an important role in the diagnosis and detection of soft tissue and skeletal disorders. Skeletal scintigraphy or bone scanning is a diagnostic study used to evaluate the distribution of osteoblastic activity or active bone formation within the body. Because no single imaging technique is ideal in all clinical situations, selecting an appropriate imaging test depends on understanding the pathophysiology of the suspected condition and limitations of each technique. This article provides a brief overview of bone scintigraphy, infection imaging, and positron emission tomography in the context of current, adult orthopedic practice.