18F-NaF PET/CT imaging of bone formation induced by bioactive glass S53P4 after mastoid obliteration

Cholesteatoma surgery in the pediatric population: remaining challenges in the era of mastoid obliteration

PURPOSE

To present the first pediatric study on the safety and efficacy of mastoid obliteration using S53P4 bioactive glass (BAG) for cholesteatoma surgery.

METHODS

A single-center retrospective cohort study was conducted. Inclusion criteria were pediatric cases (≤ 18 years) and at least at least one year of follow-up including non-echo planar diffusion-weighted MRI to assess cholesteatoma recidivism. Both canal wall up (CWU) and canal wall down (CWD) procedures were evaluated.

RESULTS

A total of 61 cases (56 patients) were included. Most cases had an otologic history before the development of the cholesteatoma. CWU procedure was performed in 18 cases (30%) and CWD procedure in 43 cases (70%). The cholesteatoma recidivism rate was 33% after a mean follow-up period of 58 months. Kaplan-Meier curve estimated a 5-year recidivism rate of 40%. Few complications were seen that were all minor and resolved spontaneously or after local or systemic treatment. Control of the infection (merchant grade 0-1) was achieved in 98% of the cases. Closure of the air-bone gap within 20 dB was achieved in 22% of the cases with complete audiometric evaluation.

CONCLUSION

In this MRI-controlled study, we show the safety and efficacy of S53P4 BAG for mastoid obliteration in a pediatric cholesteatoma cohort. Postoperative complications were both rare and minor, and a dry ear was achieved in almost all patients. Nevertheless, persistent hearing loss and the apparent high recidivism rate reflect the challenging nature of pediatric cholesteatoma.

Bioactive glass (S53P4) as obliteration material in subtotal petrosectomy: initial experience

BACKGROUND

Subtotal petrosectomy for chronic suppurative otitis media requires obliteration of the mastoid cavity and middle ear. Usually, abdominal fat is used for this purpose. However, infection is a risk of using fat, which might require revision surgery. The use of S53P4 bioactive glass with antibacterial properties seems an attractive alternative.

METHODS

Two patients with a history of chronic suppurative otitis media, complicated by profound perceptive hearing loss, had already been surgically treated, and were thereafter extensively treated conservatively. Because of recurrent chronic otorrhoea and pain, subtotal petrosectomy with obliteration of the cavity with S53P4 bioactive glass was performed.

RESULTS

Follow-up duration was 84 months and 18 months, respectively. No complications occurred peri-operatively. A dry ear was obtained and no late adverse events were observed.

CONCLUSION

S53P4 bioactive glass is feasible to use for obliteration after subtotal petrosectomy. Elimination of chronic suppurative otitis media can be achieved with this technique. The bioactive glass granules might be an attractive alternative to abdominal fat, which has a risk of infection.

Mastoid Obliteration Using S53P4 Bioactive Glass in Cholesteatoma Surgery: A 10-Year Single-Center Experience in 173 Adult Patients with Long-Term Magnetic Resonance Imaging Controlled Follow-up

OBJECTIVE

To present the long-term outcomes of mastoid obliteration in cholesteatoma surgery using S53P4 bioactive glass (BAG) in an adult population.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single-center study.

PATIENTS

All 173 adult patients who underwent primary or revision surgery for cholesteatoma with mastoid obliteration using S53P4 BAG with at least 1 year of follow-up including nonecho planar diffusion-weighted magnetic resonance imaging (MRI) (non-EP DWI MRI) and/or second-look surgery to evaluate recidivism. Both canal wall up (CWU) and canal wall down (CWD) procedures were included.

INTERVENTIONS

Patients underwent CWU or CWD mastoidectomy using S53P4 BAG.

MAIN OUTCOME AND MEASURES

Cholesteatoma recidivism, postoperative complications, Merchant grade, hearing outcome.

RESULTS

Cholesteatoma recidivism was assessed by MRI in 97% of all cases and second-look surgery look surgery in 3% of cases. After a mean follow-up period of 53 months, cholesteatoma recidivism was seen in 10% of the cases (n = 18). Using the Kaplan-Meier curve to extrapolate, a 5-year recidivism rate of 12% was estimated. Only minor complications occurred, all resolving spontaneously or after minor treatment. Merchant grade of 0 to 1 was achieved 95% of the patients, no persistently wet ears were observed. Closure of the air-bone gap within 20 dB was possible in 32%.

CONCLUSION

In this long-term (up to 10 yr) follow-up study, we demonstrated the safety of S53P4 BAG. Minimal and only minor postoperative complications were observed. The effectiveness of BAG was indicated by the low rate of recidivism, even when using non-EP DWI MRI, a sensitive and specific noninvasive technique to detect cholesteatoma recidivism.

Efficacy of treating segmental bone defects through endochondral ossification: 3D printed designs and bone metabolic activities

Three-dimensional printing (3D printing) is a promising technique for producing scaffolds for bone tissue engineering applications. Porous scaffolds can be printed directly, and the design, shape and porosity can be controlled. 3D synthetic biodegradable polymeric scaffolds intended for in situ bone regeneration must meet stringent criteria, primarily appropriate mechanical properties, good 3D design, adequate biocompatibility and the ability to enhance bone formation. In this study, healing of critical-sized (5 ​mm) femur defects of rats was enhanced by implanting two different designs of 3D printed poly(l-lactide-co-ε-caprolactone) (poly(LA-co-CL)) scaffolds seeded with rat bone marrow mesenchymal stem cells (rBMSC), which had been pre-differentiated in vitro into cartilage-forming chondrocytes. Depending on the design, the scaffolds had an interconnected porous structure of 300-500 ​μm and porosity of 50-65%. According to a computational simulation, the internal force distribution was consistent with scaffold designs and comparable between the two designs. Moreover, the defects treated with 3D-printed scaffolds seeded with chondrocyte-like cells exhibited significantly increased bone formation up to 15 weeks compared with empty defects. In all experimental animals, bone metabolic activity was monitored by positron emission tomography 1, 3, 5, 7, 11 and 14 weeks after surgery. This demonstrated a time-dependent relationship between scaffold design and metabolic activity. This confirmed that successful regeneration was highly reproducible. The in vitro and in vivo data indicated that the experimental setups had promising outcomes and could facilitate new bone formation through endochondral ossification.

Long-Term Metabolic Assessment of Cryopreserved Sternal Allograft: A Case Series

BACKGROUND

Sternal resection and reconstruction with cryopreserved allografts provides a safe alternative to traditional methods of anterior chest wall reconstruction. Despite favorable results, successful integration of the graft sternum has never been demonstrated owing to the invasiveness of bone biopsy. We describe our experience of using 18F-sodium fluoride positron emission tomography/computed tomography scans as a noninvasive method of evaluating graft integration.

METHODS

Seven patients underwent surgery and radiologic follow-up. Surgical indications were sternal metastases (n = 5) and sternal dehiscence (n = 2). Sternal reconstruction was performed using a cryopreserved cadaveric sternal allograft fixed in place with titanium plates and screws. Follow-up with 18F-sodium fluoride positron emission tomography/computed tomography scans was performed at 1 and 2 years after surgery.

RESULTS

Three patients underwent total sternectomy. Two underwent partial upper sternectomy involving the manubrium, clavicle (1 patient only), and upper sternal body; and 2 had partial sternectomy of the sternal body and xiphoid process. Focal tracer accumulation occurred at the junctions between native bone and graft bone. The median maximum standardized uptake value at 1 year was 16.8 (range, 11.2 to 37.9; interquartile range, 13.6 to 19.4), and at 2 years it was 10.8 (range, 6.1 to 30.2; interquartile range, 8.9 to 15.1). In 6 cases accumulation was lower at the second scan, whereas in 1 patient the accumulation was higher at the second scan.

CONCLUSIONS

Sternal reconstruction with cryopreserved allograft is safe and well tolerated. The 18F-sodium fluoride positron emission tomography/computed tomography scans are a useful and promising noninvasive method of demonstrating the metabolic activity of the graft and its incorporation into the host skeleton during follow-up.