Bone Graft Substitutes and Enhancement in Craniomaxillofacial Surgery

Critical-sized bone defects are a reconstructive challenge, particularly in the craniomaxillofacial (CMF) skeleton. The "gold standard" of autologous bone grafting has been the work horse of reconstruction in both congenital and acquired defects of CMF skeleton. Autologous bone has the proper balance of the protein (or organic) matrix and mineral components with no immune response. Organic and mineral adjuncts exist that offer varying degrees of osteogenic, osteoconductive, osteoinductive, and osteostimulative properties needed for treatment of critical-sized defects. In this review, we discuss the various mostly organic and mostly mineral bone graft substitutes available for autologous bone grafting. Primarily organic bone graft substitutes/enhancers, including bone morphogenic protein, platelet-rich plasma, and other growth factors, have been utilized to support de novo bone growth in setting of critical-sized bone defects. Primarily mineral options, including various calcium salt formulation (calcium sulfate/phosphate/apatite) and bioactive glasses have been long utilized for their similar composition to bone. Yet, a bone graft substitute that can supplant autologous bone grafting is still elusive. However, case-specific utilization of bone graft substitutes offers a wider array of reconstructive options.

Antibiotics in mastoid and epitympanic obliteration with S53P4 bioactive glass: A retrospective study

Objective

The role of antibiotics in ear surgery is still controversial. The aim of this study was to assess their need in cholesteatoma surgery when performing obliteration with S53P4 bioactive glass, a biocompatible material with antibacterial properties.

Methods

This retrospective cohort study was conducted in a tertiary referral center between January 2017 and May 2019. Sixty-nine consecutive patients, who underwent surgery for cholesteatoma removal and/or rehabilitation of canal-wall-down mastoidectomy with mastoid and epitympanic obliteration using S53P4 granules were included. Before 2019, antibiotics were routinely used (group "w/AB"). Patients received intravenous antibiotics during surgery, oral treatment was continued for 7 days and topical antibiotics for 1 month. After 2019, no antibiotics were administered (group "w/oAB"). The primary outcome was the occurrence of early surgical site infection. Secondary outcomes were late infection, anatomic and functional results at 3 and 12 months.

Results

Twenty-three patients were included in group "w/oAB" and 46 in group "w/AB", with no significant differences in demographics, medical history or follow-up. Five ears (22%) in group "w/oAB" developed an early infection compared with 2 (4%) in group "w/AB" (p = .03). The relative risk was 6.11, 95CI%[1.09;31.96]. Infections were successfully treated with antibiotics, and no patient underwent surgical removal of the granules. No late infections or complications were observed. There was no difference in graft failure or air-bone gap closure at 1 year.

Conclusion

Peri-/post-operative antibiotics prevent early infection in obliteration surgery with S53P4 granules. Infections can be treated medically without complications or require removal of the implanted material.

Level of evidence

4.

Mid-term outcomes of mastoid obliteration with biological hydroxyapatite versus bioglass: a radiological and clinical study

PURPOSE

Radiological assessment of osseointegration of mastoid grafts: biological hydroxyapatite (Bio-Oss®) (BHA) versus bioglass S53P4 (Bonalive®) (BG).

METHODS

Retrospective (10 ± 4 months post-surgery) monocentric high resolution computed tomography (CT) scan assessment (November 2018 and October 2020) by two independent radiologists (R1, R2), blinded to patient allocation. All patients who had undergone a total mastoid obliteration were eligible. Excluded: complications namely otological acute or chronic infections, unbalanced metabolic disease, long-term cortico-steroid therapy, auto-immune disease, history of allergy to grafting materials and post-surgery CT scan in other centers (n = 8).

PRIMARY OUTCOMES

the ratio between two regions of interests (ROI) (graft to otic capsule).

SECONDARY OUTCOMES

resorption of mastoid grafts and assessment of clinical tolerance.

RESULTS

Included 21 patients (mean age: 29 ± 21 years; 5 females, 16 males). Significantly higher osseointegration for BHA vs. BG (R1 p = 0.043; R2 p = 0.004); almost perfect inter-reader agreement k = 0.922). The ROI ratios for BHA and BG to that of the otic capsule were 0.57 ± 0.11 (R1) and 0.59 ± 0.14 (R2); 0.43 ± 0.11 (R1) and 0.43 ± 0.08 (R2), respectively. Density increased significantly by 399 ± 261 Hounsfield units (HU) (p = 0.008) and decreased by 464 ± 161 HU (p < 0.001) for BHA vs. BG. Resorption rates were 24.1 ± 21.0% and 66.7 ± 15.1% (p = 0.076), respectively. No significant difference in clinical tolerance was observed.

CONCLUSION

Post-operative CT scan of mastoid obliteration seems reliable in assessment of biomaterial graft's mid-term feasibility and stability: BHA seems to provide a more optimal osseointegration versus BG with no significant differences in graft resorption and clinical tolerance.

Implantation of two generations of Bonebridge after mastoid obliteration with bioactive glass S53P4

PURPOSE

After radical surgery for chronic cholesteatoma (CWD mastoidectomy), patients have the option to have the posterior wall of their external auditory canal surgically reconstructed with S53P4 bioactive glass. The procedure eliminates some of the restrictions related to having a postoperative cavity and extends the options for a hearing prosthesis. If classic reconstruction is not possible and a hearing aid is not used, we suggest use of a Bonebridge implant.

METHODS

This study describes, over 18 months of follow-up, 16 patients after a two-stage surgical procedure: obliteration of the mastoid cavity with bioactive glass followed by Bonebridge implantation. There were 7 patients who received the first generation implant (BCI 601) and 9 who used the second (BCI 602). Before and after implantation, pure tone audiometry, sound field thresholds, and free-field audiometry were performed. Speech reception thresholds in noise were assessed using the Polish Sentence Matrix Test. Subjective assessment of benefits was done using the APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire.

RESULTS

During the observation period, no serious complications were found. The study demonstrated the safety and validity of the procedures and confirmed the safety of using S53P4 bioactive glass in otosurgery (antibacterial effect, nonrecurrence of cholesteatoma, and no effect on the inner ear). The audiological benefits expected from using the Bonebridge implant processor were also confirmed.

CONCLUSION

It is concluded that, after reconstructing the posterior wall of the external auditory canal with bioactive glass, two-stage implantation of a Bonebridge implant in a typical site is a safe solution for patients who have difficult anatomical conditions following their CWD mastoidectomy.

Materials used for mastoid obliteration and its complications: a systematic review

OBJECTIVE

The objectives of this review are to identify the types of materials with their associated complications and respective considerations when used to obliterate the mastoid cavity.

METHODS

A systematic search was performed across PubMed, Embase, Medline and Cochrane databases from January 2009 to January 2020 for randomized controlled trials and observational studies of patients that underwent mastoid obliteration. Studies that fulfilled the inclusion criteria were screened and scored according to the MINORS and relevance scores to determine final inclusion. Types of complications were grouped into minor and major complications based on the Clavien-Dindo classification.

RESULTS

Two thousand five hundred and seventy-eight ears were evaluated. There were a total of 165 (7.9%) minor and 142 (6.8%) major complications in the autologous group. Overall complication rate is 14.8%. The major complications were largely recurrent and residual disease requiring revision surgery. There were 10 (18.5%) minor complications and three (5.6%) major complications in the allogenic group. The cumulative complications risk is 24%. For the synthetic group, there were 39 (8.0%) minor and 34 (7.6%) major complications. The cumulative complication rate is 16.6%.

CONCLUSION

Current evidence on materials for mastoid obliteration has been evolving. Each material has its strengths and limitations. The trend over the last decade favours the use of autologous materials. The principle of using a material remains being cautious of not reimplanting skin that can lead to the development of a cholesteatoma. The choice of materials is dependent on patient factors as well as the surgeons' preference and experience.

Bioactive Glass Applications: A Literature Review of Human Clinical Trials

The use of bioactive glasses in dentistry, reconstructive surgery, and in the treatment of infections can be considered broadly beneficial based on the emerging literature about the potential bioactivity and biocompatibility of these materials, particularly with reference to Bioglass® 45S5, BonAlive® and 19-93B3 bioactive glasses. Several investigations have been performed (i) to obtain bioactive glasses in different forms, such as bulk materials, powders, composites, and porous scaffolds and (ii) to investigate their possible applications in the biomedical field. Although in vivo studies in animals provide us with an initial insight into the biological performance of these systems and represent an unavoidable phase to be performed before clinical trials, only clinical studies can demonstrate the behavior of these materials in the complex physiological human environment. This paper aims to carefully review the main published investigations dealing with clinical trials in order to better understand the performance of bioactive glasses, evaluate challenges, and provide an essential source of information for the tailoring of their design in future applications. Finally, the paper highlights the need for further research and for specific studies intended to assess the effect of some specific dissolution products from bioactive glasses, focusing on their osteogenic and angiogenic potential.

The Viability and Growth of HaCaT Cells After Exposure to Bioactive Glass S53P4-Containing Cell Culture Media

HYPOTHESIS

Bioactive glass (BG) S53P4 reduces the viability of epidermal keratinocyte-derived immortalized cell line, HaCaT in sufficient concentrations in vitro.

BACKGROUND

Although used in mastoid obliteration surgery, there is no data available on whether BG S53P4 granules have an inhibitory or excitatory effect on keratinocytes, found in normal skin and ear cholesteatoma in vivo.

METHODS

HaCaT cell cultures were incubated with a direct BG S53P4 granule contact. Microscopic evaluation of the cultures was performed and interleukin-6 (IL-6) and -8 (IL-8) concentrations were measured from the medium samples. In addition, BG granules were incubated in two cell culture media for 6 days and the pure media were used in confluent HaCaT cultures preceding cell viability assay. Finally, a scratch assay test was performed to reveal the possible BG effect on HaCaT cultures.

RESULTS

Eight to ten cell thick layers of dead HaCaT cells were noticed after a 2-day BG granule contact. With a BG concentration of 2.5%, IL-6 and IL-8 concentrations were smaller compared with the control group without BG after 2 days' incubation. Overall, HaCaT cell viability decreased when BG was incubated in keratinocyte growth medium, but did not change in Dulbecco's modified Eagle's medium. In a scratch assay test, cell regrowth in the scratch area was notable in cultures without BG.

CONCLUSIONS

BG S53P4 seems to have an inhibitory effect on HaCaT cell growth. Although further studies are needed, this observation seems advantageous for cholesteatoma treatment.

Mastoid cavity obliteration using bone pâté versus bioactive glass granules in the management of chronic otitis media (squamous disease): a prospective comparative study

OBJECTIVE

To compare the efficacy of bone pâté versus bioactive glass in mastoid obliteration.

METHOD

This randomised parallel groups study was conducted at a tertiary care centre between September 2017 and August 2019. Sixty-eight patients, 33 males and 35 females, aged 12-56 years, randomly underwent single-stage canal wall down mastoidectomy with mastoid obliteration using either bone pâté (n = 35) or bioactive glass (n = 33), and were evaluated 12 months after the operation.

RESULTS

A dry epithelised cavity (Merchant's grade 0 or 1) was achieved in 65 patients (95.59 per cent). Three patients (4.41 per cent) showed recidivism. The mean air-bone gap decreased to 16.80 ± 4.23 dB from 35.10 ± 5.21 dB pre-operatively. The mean Glasgow Benefit Inventory score was 30.02 ± 8.23. There was no significant difference between the two groups in these outcomes. However, the duration of surgery was shorter in the bioactive glass group (156.87 ± 7.83 vs 162.28 ± 8.74 minutes; p = 0.01).

CONCLUSION

The efficacy of both materials was comparable.

Cognizing the crystallization aspects of NaCaPO4 concomitant 53S bioactive-structures and their imprints in in vitro bio-mineralization

Compositional and bio-physico-chemical characteristic features of bioactive glasses are of great importance in biomedical field.

Mastoid Obliteration Using Autologous Bone Dust Following Canal Wall Down Mastoidectomy

OBJECTIVE

To describe a technique for mastoid obliteration following canal wall down (CWD) mastoidectomy for chronic otitis media with cholesteatoma, and review its early results in producing a dry, safe ear, and a small mastoid cavity.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

Forty-three consecutive CWD procedures using bone dust obliteration for chronic otitis media.

INTERVENTION

All patients underwent CWD mastoidectomy and, if indicated, concurrent tympanoplasty and ossicular chain reconstruction. Bone dust harvested from healthy mastoid cortex was used to obliterate selected portions of the tympanomastoid defect. Temporalis fascia and/or an inferiorly-based periosteal flap were used for coverage of the bone dust.

MAIN OUTCOME MEASURES

Postoperative infection, need for mastoid bowl cleaning, incidence of recurrent cholesteatoma, need for revision surgical intervention.

RESULTS

At mean follow-up of 29 months, 95% of ears have remained dry and safe since mastoid obliteration, with a lack of symptoms and no evidence of recurrent disease. Cholesteatoma recurrence rate was 5%. Postoperative otorrhea, while rare, was managed successfully with topical medication in all affected patients. Clinical, radiographic, and surgical appearance of grafted bone dust suggests good take with long-term viability.

CONCLUSIONS

The described technique used for mastoid obliteration using autologous bone dust and cartilage is simple, effective, and safe to reduce the size of the mastoid cavity in patients undergoing CWD mastoidectomy. It might help to reduce morbidity by improving the surgeon's control over mastoid bowl size and shape.

Bioactive glass S53P4 eradicates Staphylococcus aureus in biofilm/planktonic states in vitro

Background: Increasing antimicrobial resistance to antibiotics is a substantial health threat. Bioactive glass S53P4 (BAG) has an antimicrobial effect that can reduce the use of antibiotics. The aim of this study was to evaluate the antimicrobial efficacy of BAG in vitro on staphylococci in biofilm and in planktonic form. Secondary aims were to investigate whether supernatant fluid primed from BAG retains the antibacterial capacity and if ciprofloxacin enhances the effect.Methods: BAG-S53P4 granules, <45 µm, primed in tryptic soy broth (TSB) were investigated with granules present in TSB (100 mg/mL) and after removal of granules (100, 200, and 400 mg/mL). The efficacy of BAG to eradicate Staphylococcus aureus biofilm in vitro was tested using 10 different clinical strains and 1 reference strain in three test systems: the biofilm-oriented antiseptic test based on metabolic activity, the biofilm bactericidal test based on culturing surviving bacteria, and confocal laser scanning microscopy (CLSM) combined with LIVE/DEAD staining.Results: Exposure to 48 h primed BAG granules (100 mg/mL) produced bactericidal effects in 11/11 strains (p = 0.001), and CLSM showed reduction of viable bacteria in biofilm (p = 0.001). Supernatant primed 14 days, 400 mg/mL, reduced metabolic activity (p < 0.001), showed bactericidal effects for 11/11 strains (p = 0.001), and CLSM showed fewer viable bacteria (p = 0.001). The supernatant primed for 48 h, or in concentrations lower than 400 mg/mL at 14 days, did not completely eradicate biofilm.Conclusion: Direct exposure to BAG granules, or primed supernatant fluid, effectively eradicated S. aureus in biofilm. The anti-biofilm effect is time- and concentration-dependent. When BAG had reached its full antimicrobial effect, ciprofloxacin had no additional effect.

Mastoid Obliteration with Synthetic Materials: A Review of the Literature

Canal wall down mastoidectomy is a surgical technique used for the eradication of middle ear disease. The remaining large mastoid bowl is associated with a number of issues; one of the main techniques that have been developed in order to avoid such problems is the obliteration of the mastoid cavity. The materials used for this reason are either biological or synthetic. The purpose of this survey is to review the published literature related to the therapeutic value of mastoid obliteration with synthetic materials. We searched Web of Science, PubMed, and MEDLINE from 2008 to 2018 using the criteria mastoid obliteration, canal wall down mastoidectomy, chronic otitis media, and cholesteatoma. The search focused on papers concerning the mastoid obliteration with synthetic material, as we focused on looking for outcomes and reported complications. Out of a total of 244 citations, 15 articles were identified, where patients underwent mastoid obliteration with synthetic materials. Most authors used bioactive glass as a filler material. Mastoid obliteration resulted in a decrease in the complications associated with the open mastoid cavity. On the basis of the available limited literature, it seems that mastoid obliteration with synthetic materials is a valuable and safe surgical technique for patients who undergo canal wall down mastoidectomy. The bioactive glass appears to be the most reliable synthetic material.

A Large Calvarial Bone Defect in a Child: Osseointegration of an Implant

BACKGROUND

This original report describes the outcome of a cranioplasty at long-term follow-up. A large calvarial bone defect of a child was reconstructed with a bioactive and biostable nonmetallic implant.

CASE DESCRIPTION

In a child with infantile fibrosarcoma of occipital bone, the malignancy was removed at 2.5 years of age, and the defect site was reconstructed with an onlay glass fiber-reinforced composite-bioactive glass implant. The follow-up examination at 5 years 7 months showed no signs of tumor recurrence. During the follow-up period, the contour of the reconstructed area followed skull anatomic development. Computed tomography demonstrated considerably large areas (approximately 70% of the total area) of bone ongrowth to the peridural surface of the implant.

CONCLUSIONS

In the future, a synthetic cranioplasty material that is able to integrate with cranial bone may be considered superior to cryopreserved bone grafts in younger age groups.

Bioactive glass granules for mastoid and epitympanic surgical obliteration: CT and MRI appearance

PURPOSE

To evaluate the appearance of mastoid and epitympanic obliteration using S53P4 bioactive glass (BG) granules in high-resolution computed tomography (HRCT) and MRI.

MATERIALS AND METHODS

Patients undergoing mastoid and epitympanic obliteration between May 2013 and December 2015 were prospectively included in an uncontrolled clinical study. All patients underwent a temporal HRCT scan 1 year after surgery, aimed at evaluating the attenuation, homogeneity, and osseointegration of the BG granules, as well as the ventilation of the middle ear and the volume of the obliterated paratympanic spaces. If a cholesteatoma was found during surgery, additional MRI, including at least pre- and post-contrast T1-weighted, T2-weighted, and axial non-echo-planar diffusion-weighted (DW) sequences, was performed 1 year after surgery, to study the normal signal of the BG granules and the presence of residual cholesteatoma and/or other temporal bone pathologies.

RESULTS

Seventy cases were included. On 1-year HRCT, the mean attenuation of the BG granules was 888.34 ± 166.10 HU. The obliteration was found to be mostly homogeneous with partial osseointegration. The appearance of the BG granules having a low-intensity signal in T2-weighted imaging and DW MRI was always different from the appearance of cholesteatoma. A longer follow-up has shown no attenuation or signal modification of the BG granules compared with the 1-year imaging.

CONCLUSION

Radiological follow-up of patients operated on with mastoid and epitympanic obliteration using BG granules is effective using both HRCT and MRI. A cholesteatoma and/or other potential complications could easily be detected due to the specific radiological appearance of the BG granules.

KEY POINTS

• The appearance of mastoid and epitympanic obliteration by S53P4 bioactive glass (BG) granules on high-resolution computed tomography (HRCT) scans was homogeneous with an attenuation significantly higher than the attenuation of cholesteatoma and lower than mastoid bone attenuation. • The granules have a low-intensity signal on non-echo-planar diffusion-weighted sequences and on T2-weighted images and present contrast enhancement allowing the differential diagnosis with cholesteatoma and effective for the detection of other underlying temporal bone pathologies. • The volume and radiological appearance of the obliteration appear to be stable with time.

Temporal bone trauma effects on auditory anatomical structures in mastoid obliteration

PURPOSE

The risk of temporal bone fractures in head trauma is not negligible, as injuries also depend on the resistance and integrity of head structures. The capacity of mastoid cells to absorb part of the impact kinetic energy of the temporal bone is diminished after open cavity mastoidectomy, even if the surgical procedure is followed by mastoid obliteration. The aim of our study was to evaluate the severity of lesions in auditory anatomical structures after a lateral impact on cadaveric temporal bones in which open cavity mastoidectomy followed by mastoid obliteration was performed, compared to cadaveric temporal bones with preserved mastoids.

METHODS

The study was carried out on 20 cadaveric temporal bones, which were randomly assigned to two groups. In the study group, open cavity mastoidectomy followed by mastoid obliteration with heterologous materials was performed. All temporal bones were impacted laterally under the same conditions. Temporal bone fractures were evaluated by CT scan.

RESULTS

External auditory canal fractures were six times more seen in the study group. Tympanic bone fractures were present in 80% of the samples in the study group and 10% in the control group (p = .005). Middle ear fractures were found in 70% of the samples in the study group and 10% in the control group (p = .02). Otic capsule violating fractures of the temporal bone were present only in the study group.

CONCLUSIONS

Mastoid obliteration with heterologous materials after open cavity mastoidectomy increases the risk of fracture, with the involvement of auditory anatomical structures.

Bioglass reconstruction of posterior meatal wall after canal wall down mastoidectomy

BACKGROUND

Canal wall down (CWD) mastoidectomy has many drawbacks including chronic otorrhea, granulations, dizziness on exposure to cold or hot water and tendency of debris accumulation in the mastoid cavity demanding periodic cleaning. Many of these problems can be solved by reconstruction of the posterior meatal wall (PMW).

OBJECTIVES

To assess the results of PMW reconstruction after CWD mastoidectomy for cholesteatoma using bioactive glass (BAG) that is fabricated and built up intraoperatively.

PATIENTS AND METHODS

This study was applied on 20 patients had atticoantral chronic suppurative otitis media. All cases were subjected to CWD mastoid surgery with complete elimination of the disease and reconstruction of the PMW by BAG that was prepared and built up intraoperatively. All patients were exposed to full preoperative evaluation and full postoperative assessment of complications, appearance of the external auditory canal contour, and the hearing gain expressed by the change of the air bone gap postoperatively.

RESULTS

During a follow up of 12 to 36 months, postoperative appearance of external auditory canal contour was found smooth without hidden pouches, irregularities nor stenosis in all cases. No registered granulation, foreign body reaction, nor extrusion and/or displacement of the BAG material. No reported facial palsy or recurrent cholesteatoma. Significant hearing improvement was statistically reported (p = 0.0006).

CONCLUSION

Surgical reconstruction of the PMW using BAG that operatively fashioned immediately after CWD mastoidectomy appears to be reliable without considerable complications giving smooth appearance of the PMW and improving the hearing.

Recent Evidence on Bioactive Glass Antimicrobial and Antibiofilm Activity: A Mini-Review

Bone defects caused by trauma or pathological events are major clinical and socioeconomic burdens. Thus, the efforts of regenerative medicine have been focused on the development of non-biodegradable materials resembling bone features. Consequently, the use of bioactive glass as a promising alternative to inert graft materials has been proposed. Bioactive glass is a synthetic silica-based material with excellent mechanical properties able to bond to the host bone tissue. Indeed, when immersed in physiological fluids, bioactive glass reacts, developing an apatite layer on the granule’s surface, playing a key role in the osteogenesis process. Moreover, the contact of bioactive glass with biological fluids results in the increase of osmotic pressure and pH due to the leaching of ions from granules’ surface, thus making the surrounding environment hostile to microbial growth. The bioactive glass antimicrobial activity is effective against a wide selection of aerobic and anaerobic bacteria, either in planktonic or sessile forms. Furthermore, bioglass is able to reduce pathogens’ biofilm production. For the aforementioned reasons, the use of bioactive glass might be a promising solution for the reconstruction of bone defects, as well as for the treatment and eradication of bone infections, characterized by bone necrosis and destruction of the bone structure.

Osteotomy Site Grafting in Bilateral Sagittal Split Surgery With Bioactive Glass S53P4 for Skeletal Stability

In orthognathic surgery, the aim of the treatment is to achieve a good occlusion and a satisfying aesthetic outcome. In large mandibular advancements insufficient healing at the mandibular inferior border may lead to loss of support for the overlaying tissue at the osteotomy site. Augmentation can be performed to improve stability, bone regeneration, and the aesthetic outcome. The purpose of this prospective clinical study was to evaluate the use of a novel material for this indication; granules of the antibacterial, osteoconductive, and slowly resorbing bioactive glass S53P4 as filling material in large mandibular advancement in bilateral sagittal split osteotomies. The authors treated 25 patients who underwent bilateral sagittal split osteotomies due to class II dentoskeletal deformities. The mandibular osteotomy site defects (8-15 mm) were augmented with bioactive glass S53P4. The average clinical follow-up was 33 months and the average radiological follow-up with cone beam computerized tomography was 24 months. The clinical and radiological results were good with regard to healing, bone regeneration, and stability of the osteotomy sites. The recontouring of the inferior mandibular border provided a good soft tissue support followed by an excellent aesthetic outcome in 96% of the osteotomy sites. The occlusion was stable in 88% of the patients. The authors' results show that bioactive glass S53P4 is a safe grafting material for osteotomy site defects in significant mandibular advancements with reliable bone regeneration, providing long-term stability at the osteotomy site and at the inferior mandibular border.

Bioactive glass obliteration of the mastoid significantly improves surgical outcome in non-cholesteatomatous chronic otitis media patients

This retrospective follow-up study evaluates the efficacy and safety of bioactive glass (BAG) S53P4 when applied as filler material in mastoid obliteration surgery performed on non-cholesteatomatous chronic otitis media (NC-COM) patients with chronically discharging ears despite conservative therapy. 94 Patients (96 ears) were included. Patients underwent either intact canal wall (ICW) or canal wall down (CWD) mastoid surgery between 2005 and 2015. The intervention group comprised 23 patients (23 ears) who were treated with additional mastoid obliteration using BAG S53P4; the remaining 71 patients (73 ears) were considered controls. All patients underwent preoperative CT scanning of the mastoid. Primary functional outcome, as defined by control of suppuration, was assessed using Merchant's scale. Hearing results as measured by air-bone gap and the incidence of adverse events were assessed as secondary outcomes. Thirty-two ears (44%) in the control group (n = 73) achieved complete control of infection at the most recent postoperative clinic visit vs 17 (74%) in the S53P4 obliteration group (n = 23). Comparing these outcomes yielded an odds ratio (OR) of 3.6 (p = 0.012, 95% CI 1.3-10.3). Complete failure to manage infection significantly differed (p = 0.048) between the control group (11 ears; 15%) and the S53P4 obliteration group (0 ears). No adverse events were observed in either group. Pre- and postoperative ABG results did not differ significantly between groups. Obliteration of the mastoid cavity using BAG S53P4 along with mastoidectomy in patients with chronically discharging NC-COM significantly improves the achievement of a dry and safe ear as compared to mastoidectomy alone. Importantly, no adverse events were observed with S53P4 BAG obliteration.

Mastoid obliteration with S53P4 bioactive glass in cholesteatoma surgery

CONCLUSION

Evaluation of the follow-up of 67 patients shows that S53P4 bioactive glass (BAG) granules are safe and effective as obliteration material in cholesteatoma surgery.

OBJECTIVES

To investigate the safety and efficacy of mastoid obliteration using S53P4 BAG in cholesteatoma surgery. Clinical outcomes were infection control (Merchant's grading), cholesteatoma recidivism, and audiometric performance.

METHODS

Retrospective follow-up study at the Diakonessenhuis, Utrecht, the Netherlands. Eighteen young (age <17 years) and 49 adult (age ≥17 years) patients treated for cholesteatoma underwent tympanomastoidectomy with mastoid obliteration using S53P4 BAG in the period 2012-2015. Outcome was monitored with clinical otoscopy, otorrhea incidence measurement (Merchant's grading), DW-MRI, and audiographic performance analyses (pure tone average and air bone gap).

RESULTS

During the follow-up period (mean = 22 months; range = 12-54 months) cholesteatoma recidivism was observed in 6% of the patients (four ears), mostly in young patients (three ears). An acceptably dry ear (Merchant grade 0-1) was achieved in 96% of all cases. The remaining 4% of cases scored a Merchant grade 2. Overall, both air conduction thresholds and air bone gap were slightly lowered when comparing post-operative values to pre-operative values and significantly in the case of ossicular reconstruction. In none of the patients (0%) did post-operative wound infections occur.

Regeneration of Cystic Bone Cavities and Bone Defects With Bioactive Glass S53P4 in the Upper and Lower Jaws

Cysts and tumors are common lesions in the jaws. To be able to retain a good volume of the alveolar ridge during healing as well as strengthening the angle and body of the mandible and provide an instant improved support for adjacent teeth, reliable long-term bone regeneration is needed. The purpose of this prospective study was to promote bone regeneration by filling bony defects in the upper or lower jaw with granules of the bioactive glass S53P4 (BAG), which have osteostimulative and antimicrobial properties.The authors treated 20 patients (21 defects) surgically; benign tumors, cysts, or infection related to impacted teeth in the maxilla or mandible. The tumor or cyst was removed or enucleated and thorough cleaning of the infected area was performed. The bone cavity was filled with granules of the BAG S53P4 despite signs of chronic infection in the area at the time of surgery. The patients were followed up for an average of 34 months clinically and with cone beam computerized tomography for 28 months. In 20 defects the final outcome was successful. Despite infection at the time of surgery in 65% of the patients, no material associated infection was seen during the follow-up. The BAG S53P4 granules were radiologically remodeled into bone after 2 years follow-up. The use of granules of the BAG S53P4 in the treatment of large bone defects provides infection-free reliable bone regeneration despite chronic infection at the time of surgery, which improves the prognosis of adjacent teeth.

Compression properties and dissolution of bioactive glass S53P4 and n-butyl-2 cyanoacrylate tissue adhesive-composite

Bioactive glass (BG)-containing fiber-reinforced composite implants, typically screw-retained, have started to be used clinically. In this study, we tested the mechanical strength of composites formed by a potential implant adhesive of n-butyl-2-cyanoacrylate glue and BG S53P4 particles. Water immersion for 3, 10 or 30 days had no adverse effect on the compression strength. When cyanoacrylate glue-BG-composites were subjected to simulated body fluid immersion, the average pH rose to 7.52 (SD 0.066) from the original value of 7.35 after 7 days, and this pH increment was smaller compared to BG particle-group or fibrin glue-BG-composite group. Based on these results n-butyl-2 cyanoacrylate glue, by potentially producing a strong adhesion, might be considered a possible alternative for fixation of BG S53P4 containing composite implants. However, the mechanical and solubility properties of the cyanoacrylate glue may not encourage the use of this tissue adhesive with BG particles.

Anatomical, functional and quality-of-life results for mastoid and epitympanic obliteration with bioactive glass s53p4: a prospective clinical study

OBJECTIVE

To analyse the anatomical, functional and quality-of-life results when using bioactive glass in mastoid and epitympanic obliteration.

DESIGN

Prospective clinical study.

SETTING

Tertiary referral centre.

PARTICIPANTS

Forty-one cases (39 patients) operated between May 2013 and January 2015.

MAIN OUTCOME MEASURES

Anatomical results were evaluated by otomicroscopy 1 year after surgery and using imaging to detect residual disease. Functional results were studied by postoperative hearing gain. Quality of life was assessed with the Glasgow Benefit Inventory questionnaire and the success of surgery by a surgery-specific questionnaire.

RESULTS

At 1 year, all patients presented a well-healed external auditory canal, with an intact tympanic membrane. In cases with cholesteatoma (n = 23), no recurrent retraction pockets or residual disease were observed on imaging studies. The overall air-bone gap closure was 7.7 ± 1.84 dB (mean ± se of the mean, P < 0.001, paired t-test). No significant differences were found on hearing results when comparing primary versus revision surgery, canal-wall-up versus canal-wall-down obliterations, type of tympanoplasty and presence of cholesteatoma (multifactor anova). The Glasgow Benefit Inventory improved with an average score of 28 and the success of surgery questionnaire showed a significant improvement in ear discharge and a moderate improvement in hearing and equilibrium.

CONCLUSIONS

The use of bioactive glass for mastoid and epitympanic obliteration in canal-wall-down or canal-wall-up tympanoplasties is an effective procedure in both primary and revision surgery. The anatomical and functional results appear to be well correlated with patient experience and to the improvement in quality of life.

Reconstruction of Vertebral Bone Defects using an Expandable Replacement Device and Bioactive Glass S53P4 in the Treatment of Vertebral Osteomyelitis: Three Patients and Three Pathogens

BACKGROUND AND AIMS

Bioactive glass S53P4 is an antibacterial bone substitute with bone-bonding and osteostimulative properties. The bone substitute has been successfully used clinically in spine; trauma; orthopedic; ear, nose, and throat; and cranio-maxillofacial surgeries. Bioactive glass S53P4 significantly reduces the amount of bacteria in vitro and possesses the capacity to kill both planktonic bacteria and bacteria in biofilm. Three patients with severe spondylodiscitis caused by Mycobacterium tuberculosis, Candida tropicalis, or Staphylococcus aureus were operatively treated due to failed conservative treatment. The vertebral defects were reconstructed using bioactive glass S53P4 and an expandable replacement device.

MATERIAL AND METHODS

Decompression and a posterolateral spondylodesis, using transpedicular fixation, were performed posteriorly in combination with an anterior decompression and reconstruction using an expandable vertebral body replacement device. For patients 1 and 2, the expander was covered with bioactive glass S53P4 only, and for patient 3, the glass was mixed with autograft bone.

RESULTS

The patients healed well with complete neurological recovery. Fusion was observed for all patients. The total follow-up was 4 years for patient 1, 1 year and 8 months for patient 2, and 2 years and 2 months for patient 3. No relapses or complications were observed.

CONCLUSION

The antibacterial properties of bioactive glass S53P4 also make it a suitable bone substitute in the treatment of severe spondylodiscitis.

Mechanical behaviour of Bioactive Glass granules and morselized cancellous bone allograft in load bearing defects

Bioactive Glass (BAG) granules are osteoconductive and possess unique antibacterial properties for a synthetic biomaterial. To assess the applicability of BAG granules in load-bearing defects, the aim was to compare mechanical behaviour of graft layers consisting of BAG granules and morselized cancellous bone allograft in different volume mixtures under clinically relevant conditions. The graft layers were mechanically tested, using two mechanical testing modalities with simulated physiological loading conditions: highly controllable confined compression tests (CCT) and more clinically realistic in situ compression tests (ISCT) in cadaveric porcine bone defects. Graft layer impaction strain, residual strain, aggregate modulus, and creep strain were determined in CCT. Graft layer porosity was determined using micro computed tomography. The ISCT was used to determine graft layer subsidence in bone environment. ANOVA showed significant differences (p<0.001) between different graft layer compositions. True strains absolutely decreased for increasing BAG content: impaction strain -0.92 (allograft) to -0.39 (BAG), residual strain -0.12 to -0.01, and creep strain -0.09 to 0.00 respectively. Aggregate modulus increased with increasing BAG content from 116 to 653MPa. Porosity ranged from 66% (pure allograft) to 15% (pure BAG). Subsidence was highest for allograft, and remarkably low for a 1:1 BAG-allograft volume mixture. Both BAG granules and allograft morsels as stand-alone materials exhibit suboptimal mechanical behaviour for load-bearing purpose. BAG granules are difficult to handle and less porous, whereas allograft subsides and creeps. A 1:1 volume mixture of BAG and allograft is therefore proposed as the best graft material in load-bearing defects.

Cutaneous and Labyrinthine Tolerance of Bioactive Glass S53P4 in Mastoid and Epitympanic Obliteration Surgery: Prospective Clinical Study

Objective. To evaluate the cutaneous and the inner ear tolerance of bioactive glass S53P4 when used in the mastoid and epitympanic obliteration for chronic otitis surgery. Material and Methods. Forty-one cases have been included in this prospective study. Cutaneous tolerance was clinically evaluated 1 week, 1 month, and 3 months after surgery with a physical examination of the retroauricular and external auditory canal (EAC) skin and the presence of otalgia; the inner ear tolerance was assessed by bone-conduction hearing threshold 1 day after surgery and by the presence of vertigo or imbalance. Results. All surgeries but 1 were uneventful: all patients maintained the preoperative bone-conduction hearing threshold except for one case in which the round window membrane was opened during the dissection of the cholesteatoma in the hypotympanum and this led to a dead ear. No dizziness or vertigo was reported. Three months after surgery, healing was achieved in all cases with a healthy painless skin. No cases of revision surgery for removal of the granules occurred in this study. Conclusion. The bioactive glass S53P4 is a well-tolerated biomaterial for primary or revision chronic otitis surgery, as shown by the local skin reaction which lasted less than 3 months and by the absence of labyrinthine complications.

Clinical Applications of S53P4 Bioactive Glass in Bone Healing and Osteomyelitic Treatment: A Literature Review

Nowadays, S53P4 bioactive glass is indicated as a bone graft substitute in various clinical applications. This review provides an overview of the current published clinical results on indications such as craniofacial procedures, grafting of benign bone tumour defects, instrumental spondylodesis, and the treatment of osteomyelitis. Given the reported results that are based on examinations, such as clinical examinations by the surgeons, radiographs, CT, and MRI images, S53P4 bioactive glass may be beneficial in the various reported applications. Especially in craniofacial reconstructions like mastoid obliteration and orbital floor reconstructions, in grafting bone tumour defects, and in the treatment of osteomyelitis very promising results are obtained. Randomized clinical trials need to be performed in order to determine whether bioactive glass would be able to replace the current golden standard of autologous bone usage or with the use of antibiotic containing PMMA beads (in the case of osteomyelitis).

Bioactive-glass in Oral and Maxillofacial Surgery

The use of synthetic materials to repair craniofacial defects is increasing today and will increase further in the future. Because of the complexity of the anatomy in the head and neck region, reconstruction and augmentation of this area pose a challenge to the surgeon. This review discusses key facts and applications of traditional reconstruction bone substitutes, also offering comparative information. It then describes the properties and clinical applications of bioactive-glass (B-G) and its variants in oral and maxillofacial surgery, and provides clinical findings. The discussion of each compound includes a description of its composition and structure, the advantages and shortcomings of the material, and its current uses in the field of osteoplastic and reconstructive surgery. With a better understanding of the available alloplastic implants, the surgeon can make a more informed decision as to which implant would be most suitable in a particular patient.

The use of anatomically drop-shaped bioactive glass S53P4 implants in the reconstruction of orbital floor fractures--A prospective long-term follow-up study

An isolated fracture of the orbital floor needs reconstruction if there is a clear herniation of adipose tissue or of the rectus inferior muscle into the maxillary sinus. A prospective study was carried out treating 20 patients with an isolated blow-out fracture of the orbital floor or with a combined zygomatico-orbito-maxillary complex fracture, using a newly designed anatomically drop-shaped implants made of bioactive glass (BAG) S53P4. Computed tomography (CT) was performed immediately postoperatively to confirm the correct position of the plate. The patients were followed up for an average of 32 months clinically and radiologically with magnetic resonance imaging (MRI) for an average of 31 months. None of the patients had any signs of complications related to the implant and the clinical outcome was very good. None of the patients had persisting diplopia. The level of the pupillas was normal in 15 of 20 patients. Minor hypo-ophthalmos ranging from 0.5 to 1.0 mm was observed in three patients, and moderate hypo-ophthalmos of 2.0 mm was seen in one patient. Hyperophthalmos of 1.0 mm was seen in one patient. Minor enophthalmos on the operated side ranging from 0.5 to 1.0 mm was seen in eight patients. Mild to moderate paraesthesia of the infraorbital nerve was observed in six patients. The immediate postoperative CT and the long term follow-up MRI revealed that the drop-shaped BAG implants retained their correct position in the orbital floor and did not show any evidence of losing their original shape or material resorption. No adverse tissue reaction was associated with the material. Due to the anatomical drop shape, the implants could successfully maintain the orbital volume and compensate for the retrobulbar adipose tissue atrophy.

Paediatric cranial defect reconstruction using bioactive fibre-reinforced composite implant: early outcomes

BACKGROUND

In children, approximately half of cryopreserved allograft bone flaps fail due to infection and resorption. Synthetic materials offer a solution for allograft bone flap resorption. Fibre-reinforced composite with a bioactive glass particulate filling is a new synthetic material for bone reconstruction. Bioactive glass is capable of chemically bonding with bone and is osteoinductive, osteoconductive and bacteriostatic. Fibre-reinforced composite allows for fabricating thin (0.8 mm) margins for implant, which are designed as onlays on the existing bone. Bioactive glass is dissolved over time, whereas the fibre-reinforced composite serves as a biostable part of the implant, and these have been tested in preclinical and adult clinical trials. In this study, we tested the safety and other required properties of this composite material in large skull bone reconstruction with children.

METHOD

Eight cranioplasties were performed on seven patients, aged 2.5-16 years and having large (>16 cm(2)) skull bone defects. The implant used in this study was a patient-specific, glass-fibre-reinforced composite, which contained a bioactive glass particulate compound, S53P4.

RESULTS

During follow-up (average 35.1 months), one minor complication was observed and three patients needed revision surgery. Two surgical site infections were observed. After treatment of complications, a good functional and cosmetic outcome was observed in all patients. The implants had an onlay design and fitted the defect well. In clinical and imaging examinations, the implants were in the original position with no signs of implant migration, degradation or mechanical breakage.

CONCLUSIONS

Here, we found that early cranioplasty outcomes with the fibre-reinforced composite implant were promising. However, a longer follow-up time and a larger group of patients are needed to draw firmer conclusions regarding the long-term benefits of the proposed novel biomaterial and implant design. The glass-fibre-reinforced composite implant incorporated by particles of bioactive glass may offer an original, non-metallic and bioactive alternative for reconstruction of large skull bone defects in a paediatric population.

A comparative study of the use of bioactive glass S53P4 and antibiotic-loaded calcium-based bone substitutes in the treatment of chronic osteomyelitis: a retrospective comparative study

The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed. In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups. After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate. Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes.

Bioactive glass BAG-S53P4 for the adjunctive treatment of chronic osteomyelitis of the long bones: an in vitro and prospective clinical study

BACKGROUND

This study aimed to explore the in vitro antibacterial activity of the bioglass BAG S53P4 against multi-resistant microorganisms commonly involved in osteomyelitis and to evaluate its use in surgical adjunctive treatment of osteomyelitis.

METHODS

In vitro antibacterial activity of BAG-S53P4 against methicillin resistant Staphylococcus aureus and Staphylococcus epidermidis, Pseudomonas aeruginosa and Acinetobacter baumannii isolates was evaluated by means of time kill curves, with colony counts performed after 24, 48 and 72 hours of incubation. In vivo evaluation was performed by prospectively studying a cohort of 27 patients with a clinically and radiologically diagnosed osteomyelitis of the long bones in an observational study. Endpoints were the absence of infection recurrence/persistence at follow-up, no need for further surgery whenever during follow-up and absence of local or systemic side effects connected with the BAG use.

RESULTS

In vitro tests regarding the antibacterial activity of BAG S53P4 showed a marked bactericidal activity after 24 hrs against all the tested species. This activity continued in the subsequent 24 hrs and no growth was observed for all strains after 72 hrs. Results of the clinical study evidenced no signs of infection in 24 patients (88.9%) at the follow-up, while 2 subjects showed infection recurrence at 6 months from index operation and one more needed further surgical procedures. BAG-S53P4 was generally well tolerated.

CONCLUSIONS

The in vitro and in vivo findings reinforce previous observations on the efficacy of BAG-S53P4 for the treatment of chronic osteomyelitis of the long bones, also in the presence of multi-resistant strains and in immunocompromised hosts, without relevant side effects and without the need for locally adding antibiotics.

TRIAL REGISTRATION

Deutschen Register Klinischer Studien (DRKS) unique identifier: DRKS00005332.

Craniofacial bone reconstruction with bioactive fiber-reinforced composite implant

BACKGROUND

A novel, bioactive, fiber-reinforced composite implant is a solution to address the shortcomings in craniofacial bone reconstruction. A longitudinal clinical investigation with a follow-up time of 4 years was conducted.

METHODS

A cranial bone reconstruction with the implant was performed on 12 patients. In these patients, the reasons for craniotomies resulting in craniofacial bone defects were traumatic and spontaneous intracranial bleeding as well as infections to the primary reconstruction material. The implant material consisted of a supporting fiber-reinforced framework, porous inner layers, and a bioactive glass (BG; S53P4) filling. The framework and the porous layers were made of a bisphenol-a-glycidyl methacrylate and triethyleneglycoldi-methacrylate (pBisGMA-pTEGDMA) resin matrix, which was reinforced with silanized E-glass.

RESULTS

In clinical examinations and skull X-rays, the implants were in original positions providing the expected functional and aesthetic outcome at all time points.

CONCLUSION

The implants functioned appropriately, which would provide a potential solution for craniofacial bone reconstruction in the future.

Use of granules of biphasic ceramic in rehabilitation of canal wall down mastoidectomy

The objective of this study is to evaluate the anatomical and functional results of rehabilitation of canal wall down (CWD) mastoidectomy using granules of biphasic ceramic. This is a study design retrospective in a tertiary referral centre Fifty-seven patients (59 ears) operated on between 2006 and 2010 of mastoid obliteration with granules of biphasic ceramic (TricOs, Maurepas, France) have been included (55 revisions and 4 first surgeries). Forty-six patients presented already a CWD mastoidectomy. The mean pre-operative bone conduction (BC) was 29 ± 3.4 dB (mean ± SEM) and mean air conduction (AC) was 57 ± 3.2 dB. Cholesteatoma was found in 33 cases. All but seven cases had post-operative otoscopy examination at 1, 3, 6 months, and 1 year postoperative with a CT scan and pure tone audiometry. Mean follow-up was 14 ± 1.8 months (3-35). At one-year follow-up (n = 52), 47 cases (90 %) presented well-healed external auditory canal. Five cases (10 %) of uncovered granules without sign of infection of external auditory canal skin were observed. Mean post-operative threshold was 25 ± 1.8 and 46 ± 1.9 dB for BC and AC , respectively (n = 47). CT scan (n = 42) showed no opacity suggesting residual disease within or behind obliteration. Mastoid obliteration with granules of biphasic ceramic is a safe and effective procedure that allows restoration of a near normal external auditory canal.