Review of Maxillofacial Hardware Complications and Indications for Salvage

Robot-assisted versus traditional fixation for the treatment of calcaneal fractures: a meta-analysis

OBJECTIVE

With the development of surgical technology, the level of digital medicine is constantly improving. The birth of new technologies has a certain impact on traditional methods. At present, robot-assisted technology has been applied to patients with calcaneal fractures, which poses a challenge to traditional surgery. We aimed to assess whether robot-assisted internal fixation confers certain surgical advantages through a literature review.

DESIGN

The databases PubMed, EMBASE, the Cochrane Library, the China National Knowledge Infrastructure (CNKI), and the Wanfang Data Knowledge Service Platform were systematically searched for both randomized and nonrandomized studies involving patients with calcaneal fractures.

MAIN RESULTS

Five studies were identified that compared clinical indexes. For the clinical indexes, robot-assisted surgery is generally feasible because of intraoperative fluoroscopy, complications, the Gissane angle, the calcaneal width, and the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score 3 and 6 months after the operation (P < 0.05). However, on the operation time, Böhler's angle at 3 and 6 months, Gissane angle and calcaneal width at 6 months after the operation did not show good efficacy compared with those of the traditional group (P > 0.05).

CONCLUSIONS

Based on the current evidence, the advantages of robot-assisted fixation over traditional fixation are clear. The long-term clinical effects of the two methods are also good, and the short-term effect of robot assistance is better. However, the quality of some studies is low, and more high-quality randomized controlled trials (RCTs) are needed for further verification.

The role of CT-DCG in hardware - associated secondary acquired lacrimal duct obstruction: SALDO update study - (SUP) - Paper III

Purpose

To study cases of hardware-associated secondary acquired lacrimal duct obstructions (SALDO) and the role of computed tomography dacryocystography (CT-DCG) scans in its diagnosis and management.

Observations

Retrospective, interventional case review of four patients diagnosed as Hardware-associated SALDO, with primary maxillofacial repair performed elsewhere, were analyzed. The mean age was 36.5 years (range: 22-74 years), three of them being males. Left and right lacrimal systems were equally involved. Epiphora, swelling and discharge were the main presenting features. Three lacrimal sacs and nasolacrimal ducts on CT-DCG showed the screws of the orbital fracture plate directly piercing their walls, whereas a single case showed the sac displaced and pierced by the medial side of the orbital floor implant. Two cases underwent dacryocystorhinostomy with intubation, and the remaining two had to undergo dacryocystectomy due to extensive damage. Post-operatively all four cases were doing well at a mean follow-up of 2 months.

Conclusions

The present series highlights the role of CT-DCG in delineating spatial relationship of lacrimal drainage system with the surrounding structures, facilitating planning as well as choice of surgery, and anticipating the intraoperative challenges. It also signifies importance of interdisciplinary coordination between oculoplastic and maxillofacial surgeons to avoid iatrogenic trauma to the lacrimal drainage system.

A Comprehensive Review on Managing Fracture Calcaneum by Surgical and Non-surgical Modalities

This comprehensive review delves into the multifaceted landscape of calcaneal fractures, thoroughly examining their aetiology, clinical presentation, and diverse management strategies. Encompassing surgical and non-surgical approaches, the review scrutinises critical aspects such as patient compliance, rehabilitation protocols, and long-term follow-up considerations. Surgical modalities, propelled by recent innovations like minimally invasive techniques and advanced fixation materials, are juxtaposed with non-surgical interventions, emphasising the pivotal role of patient education and adherence to optimise outcomes. The synthesis of critical findings underscores the need for individualised care and multidisciplinary collaboration in clinical practice. Moreover, the review outlines recommendations for healthcare practitioners and identifies promising areas for future research, including biomechanical studies and telerehabilitation. This comprehensive exploration aims to contribute to the ongoing evolution of calcaneal fracture management, ultimately enhancing patient care and outcomes in this complex orthopaedic realm.

Risk Factors for Hardware Removal Following Bimaxillary Surgery: A National Database Analysis

Orthognathic surgery typically relies on the rigid fixation of fracture fragments using metal hardware. Though hardware is usually intended to be implanted permanently, the removal of hardware (ROH) is sometimes indicated for a variety of reasons. The authors sought to identify risk factors for ROH following orthognathic surgery. The authors conducted a retrospective analysis of the Merative MarketScan Research Databases, 2007-2021 using Current Procedural Terminology (CPT) and International Classification of Disease (ICD-9 and ICD-10) codes to identify patients who underwent an index Le Fort 1 osteotomy and bilateral sagittal split osteotomy operation on the same day. Statistical analysis involved χ2, Shapiro-Wilk, Wilcoxon-Mann-Whitney, Poisson regression, and multivariable logistic regression tests. 4698 patients met the inclusion criteria. The mean age at surgery was 25 years, and 57% were female. ROH occurred in 5.9% of patients. The mean time to hardware removal was 190.5±172.4 days. In a multivariate logistic regression, increased odds of ROH were associated with older patient age [OR: 1.02 (1.01-1.03), P=0.046], sleep apnea [OR: 1.62 (1.13-2.32), P=0.018], and craniofacial syndrome and/or cleft diagnoses [OR: 1.88 (1.14-2.55), P<0.001]. In the same model, postoperative oral antibiotic prophylaxis was not associated with ROH (P=0.494). The incidence of all-cause complications [IRR: 1.03 (1.01-1.05), P<0.001] rose over the study period, while the incidence of ROH did not change significantly (P=0.281). Patients at elevated risk should be counseled on the increased possibility of a second operation for ROH before having orthognathic surgery to ensure expectations and health care utilization decisions align with the evidence.

Management of Complications and Secondary Deformity After Fractures of the Midface, Orbit, and Upper Third of the Maxillofacial Skeleton

Craniomaxillofacial trauma is a challenging entity to manage effectively and often necessitates serial evaluation and treatment. A multidisciplinary team is best served to evaluate and treat these complex injury patterns with the use of necessary adjuncts, such as neuronavigation, intraoperative imaging, custom implant use, and virtual surgical planning. Complications of facial trauma can present at a spectrum of time points and manifest in a variety of manners and as such patients should be observed closely and longitudinally. Although not all complications and secondary deformities can be avoided, this article highlights some common pitfalls and our unique management strategies.

Characteristics and Complication Rates of Mandibular Fractures Caused by Violent Mechanisms Versus Nonviolent Mechanisms

Background

Mandibular fractures due to intentionally violent mechanisms represent a unique subset of facial fractures. The objective of our research is to identify how violence affects patterns of mandibular fractures and their outcomes.

Methods

In this institutional review board-approved, retrospective study, we examined our institution's records for adult patients >18 years of age who presented with ≥ 1 mandibular fractures from January 2011 to January 2022. Violence was defined as trauma intended to hurt another or self. Demographics, fractures, mechanism, concomitant injuries, treatment, and complications were analyzed with Excel and SPSS statistical software.

Results

A total of 692 patients were diagnosed with mandibular fractures, with 323 of these due to violence (47%). These patients of violence (POVs) had an average fracture per patient of 1.6 ± 0.7. The majority (88%) were male and African American (33%), and the average age was 34.3 ± 13.2 years. The most common violent mechanism was a punch (68%). The POVs presented with fewer concomitant injuries, were less likely to be admitted to the intensive care unit, and were more often surgically managed with open reduction than were patients of nonviolence (PONVs) (P < .01). POVs were more likely to have healing complications; though not statistically significant, this population was observed to be frequently lost to follow-up (P = .12). POVs notably had a much higher proportion of hardware exposure among complications than was seen in PONVs (23% vs 9%).

Conclusions

Patients with violent fracture mechanisms may tend to be predisposed to more complications compared with patients who have nonviolent fracture mechanisms despite lesser severities due to social determinants of health. Characteristics of this patient subset may tend to cause difficulties in postoperative care and follow-up. Effective discharge instruction communication, patient outreach programs, and homelessness and drug abuse screening in this subset may help reduce healing complications.

Prophylactic removal of titanium osteosynthesis miniplates in patients after midface fractures - A retrospective cohort study

The aim of the study was to evaluate prophylactic removal of titanium osteosynthesis miniplates in patients after midface fractures. Complaints after fracture treatment and complications after plate removal were analyzed, retrospectively. A total of 205 patients were included. Plate removal was performed in 99 cases. Complaints related to the osteosynthesis material resulted in more frequent plate removal (p < 0.001). Complications were noted in 22 patients after plate removal. Duration of plate removal did not correlate with postoperative complications. In 69 patients, plates were removed without previous symptoms. Of these patients, postoperative complications were recorded in 15 cases. In patients with complaints after osteosynthesis, complications after plate removal occurred in seven (23.3%) patients. Ectropia developed significantly more often with increasing age (p < 0.05). CONCLUSION: Within the limitations of the study it seems that prophylactic plate removal is a treatment option that is not associated with an increased complication rate.

Comprehensive analysis of patients with failure of mandibular hardware

OBJECTIVE

The purpose of the study was to characterize patients who had failure of mandibular hardware (FMH).

STUDY DESIGN

This retrospective cohort study consisted of patients with mandible fractures (MFs) that required surgical intervention from 2012 to 2020. Patients were included when mandibular hardware failed. Descriptive variables were collected.

RESULTS

During the study period, 57 patients (47 male, average age 38.7 years) met the inclusion criteria. Incidence of FMH was 7.4%. Most patients were African American (n = 45, 78.9%) with American Society of Anesthesiologists classification II (n = 40, 70.2%). Tobacco use (n = 31, 54.4%) and/or alcohol (n = 33, 57.9%). The most common etiology was assault (n = 28, 49.1%). The most common location was the angle of the mandible. Most mandibles had fracture at 1 location (n = 31, 54.4%) and a tooth was involved in the fracture line (n = 44, 77.2%). More than half of patients were treated with transoral surgical approach (n = 35, 61.4%). The majority of patients received preoperative antibiotics (n = 51, 89.4%). Patients had varying levels of compliance with postoperative care, and most were not compliant. Infection (n = 45) was the most common presentation of FMH.

CONCLUSION

High American Society of Anesthesiologists score, smoking, excessive alcohol use, parafunctional habits, and compliance with postoperative instructions may affect surgical outcome.

Biodegradable Zn-Cu-Fe Alloy as a Promising Material for Craniomaxillofacial Implants: An in vitro Investigation into Degradation Behavior, Cytotoxicity, and Hemocompatibility

Zinc-based nanoparticles, nanoscale metal frameworks and metals have been considered as biocompatible materials for bone tissue engineering. Among them, zinc-based metals are recognized as promising biodegradable materials thanks to their moderate degradation rate ranging between magnesium and iron. Nonetheless, materials’ biodegradability and the related biological response depend on the specific implant site. The present study evaluated the biodegradability, cytocompatibility, and hemocompatibility of a hot-extruded zinc-copper-iron (Zn-Cu-Fe) alloy as a potential biomaterial for craniomaxillofacial implants. Firstly, the effect of fetal bovine serum (FBS) on in vitro degradation behavior was evaluated. Furthermore, an extract test was used to evaluate the cytotoxicity of the alloy. Also, the hemocompatibility evaluation was carried out by a modified Chandler-Loop model. The results showed decreased degradation rates of the Zn-Cu-Fe alloy after incorporating FBS into the medium. Also, the alloy exhibited acceptable toxicity towards RAW264.7, HUVEC, and MC3T3-E1 cells. Regarding hemocompatibility, the alloy did not significantly alter erythrocyte, platelet, and leukocyte counts, while the coagulation and complement systems were activated. This study demonstrated the predictable in vitro degradation behavior, acceptable cytotoxicity, and appropriate hemocompatibility of Zn-Cu-Fe alloy; therefore, it might be a candidate biomaterial for craniomaxillofacial implants.

In Silico Biomechanical Evaluation of WE43 Magnesium Plates for Mandibular Fracture Fixation

Titanium fixation devices are the gold standard for the treatment of mandibular fractures; however, they present serious limitations, such as non-degradability and generation of imaging artifacts. As an alternative, biodegradable magnesium alloys have lately drawn attention due to their biodegradability and biocompatibility. In addition, magnesium alloys offer a relatively high modulus of elasticity in comparison to biodegradable polymers, being a potential option to substitute titanium in highly loaded anatomical areas, such as the mandible. This study aimed to evaluate the biomechanical competence of magnesium alloy WE43 plates for mandibular fracture fixation in comparison to the clinical standard or even softer polymer solutions. A 3D finite element model of the human mandible was developed, and four different fracture scenarios were simulated, together with physiological post-operative loading and boundary conditions. In a systematic comparison, the material properties of titanium alloy Ti-6Al-4V, magnesium alloy WE43, and polylactic acid (PLA) were assigned to the fixation devices, and two different plate thicknesses were tested. No failure was predicted in the fixation devices for any of the tested materials. Moreover, the magnesium and titanium fixation devices induced a similar amount of strain within the healing regions. On the other hand, the PLA devices led to higher mechanical strains within the healing region. Plate thickness only slightly influenced the primary fixation stability. Therefore, magnesium alloy WE43 fixation devices seem to provide a suitable biomechanical environment to support mandibular fracture healing in the early stages of bone healing. Magnesium WE43 showed a biomechanical performance similar to clinically used titanium devices with the added advantages of biodegradability and radiopacity, and at the same time it showed a remarkably higher primary stability compared to PLA fixation devices, which appear to be too unstable, especially in the posterior and more loaded mandibular fracture cases.

In vivo biocompatibility evaluation of 3D-printed nickel-titanium fabricated by selective laser melting

Nickel-titanium (NiTi) belongs to the group of shape-memory alloys (SMAs), which are characterized by flexibility and reversible deformability. Advanced techniques in 3D printing by selective laser-melting (SLM) process allow the manufacturing of complex patient-specific implants from SMAs. Osteosynthesis materials made of NiTi could be used for minimally invasive surgical approaches in oral- and maxillofacial surgery. However, the in vivo biocompatibility has not yet been fully investigated, especially in load-sharing and load-bearing implants. The aim of this study was to evaluate the in vivo biocompatibility of SLM-produced NiTi for intraosseous and subperiosteal applications. Test specimens were implanted into the frontonasal bone of ten miniature pigs. To assess peri-implant bone metabolism, fluorescent dye was administered after 2, 4, 6, 10, 12, and 14 weeks intraperitoneally. Specimens and the surrounding tissues were harvested after 8 and 16 weeks for histological analysis. While the NiTi implants presented a higher bone-to-implant contact ratio (BIC) after 8 than after 16 weeks (43.3 vs. 40.3%), the titanium implants had a significantly higher BIC after 16 weeks (33.6 vs. 67.7%). Histologically, no signs of peri-implant inflammation or foreign-body reaction were detectable. With respect to this preliminary study design, 3D-printed NiTi shows sufficient biocompatibility for intraosseous and subperiosteal implant placement.

Improved in vivo osseointegration and degradation behavior of PEO surface-modified WE43 magnesium plates and screws after 6 and 12 months

Magnesium is a highly promising candidate with respect to its future use as a material for resorbable implants. When magnesium degrades, hydrogen gas is released. High doses of gas emergence are reported to impair osseointegration and may therefore lead to fixation failure. The successful delay and reduction of the degradation rate by applying plasma electrolytic oxidation (PEO) as a post processing surface modification method for magnesium alloy has recently been demonstrated. The aim of this study was thus to compare the degradation behavior of a WE43-based plate system with and without respective PEO surface modification and to further investigate osseointegration, as well as the resulting effects on the surrounding bony tissue of both variants in a miniature pig model. WE43 magnesium screws and plates without (WE43) and with PEO surface modification (WE43-PEO) were implanted in long bones of Göttingen Miniature Pigs. At six and twelve months after surgery, micro-CT and histomorphometric analysis was performed. Residual screw volume (SV/TV; WE43: 28.8 ± 21.1%; WE43-PEO: 62.9 ± 31.0%; p = 0.027) and bone implant contact area (BIC; WE43: 18.1 ± 21.7%; WE43-PEO: 51.6 ± 27.7%; p = 0.015) were increased after six months among the PEO-modified implants. Also, surrounding bone density within the cortical bone was not affected by surface modification (BVTV; WE43: 76.7 ± 13.1%; WE43-PEO: 73.1 ± 16.2%; p = 0.732). Intramedullar (BV/TV; WE43: 33.2 ± 16.7%; WE43-PEO 18.4 ± 9.0%; p = 0.047) and subperiosteal (bone area; WE43: 2.6 ± 3.4 mm²; WE43-PEO: 6,9 ± 5.2 mm²; p = 0.049) new bone formation was found for both, surface-modified and non-surface-modified groups. After twelve months, no significant differences of SV/TV and BV/TV were found between the two groups. PEO surface modification of WE43 plate systems improved osseointegration and significantly reduced the degradation rate within the first six months in vivo. Osteoconductive and osteogenic stimulation by WE43 magnesium implants led to overall increased bone growth, when prior PEO surface modification was conducted.

Reconstruction of Posttraumatic Nasal Defect Through Paramedian Frontal Flap

ABSTRACT

Facial injuries caused by motorcycle accidents represent a challenge for reconstructions. Currently, the most indicated treatment for facial fractures is anatomical reduction and internal fixation, however, this procedure is not exempt from complications, such as infection and exposure of osteosynthesis material, thus requiring a new surgical procedure and repair. In this study, the authors describe a case of a 60-year-old woman who was the victim of a motorcycle accident and developed exposure of osteosynthesis material on the nasal dorsum after treatment of facial fractures. The patient underwent surgical treatment with objective of removing the osteosynthesis material and associated infected tissue, as well as reconstruction using a paramedian frontal flap, which resulted in a harmonic relationship and skin color similar to the recipient area. This case shows the importance of anatomical knowledge and reconstructive techniques for hard and soft tissues.

Hardware Removal in Maxillofacial Trauma: A Retrospective Study

Background

Miniplates are commonly used for the fixation of maxillofacial fracture segments. Removal of the hardware is controversial. A retrospective study of medical records was performed to observe the reasons for plate removal.

Materials and Methods

A 10-year retrospective study of medical records was performed. Demographics, type of fracture, location, type of miniplate used, the time gap between the insertion and removal, and causes of hardware removal were assessed.

Results

About 1472 patients had undergone internal fixation for the facial fractures. Stainless steel miniplate was used in 489 patients, and titanium was used in 983 patients. Out of the 42 cases, 22 cases involved the removal of titanium hardware and 20 patients involved the removal of stainless steel hardware. Infection/osteomyelitis was the main cause of hardware removal. The maximum amount of hardware failure was in the mandible. 78.6% of hardware removal was performed in males.

Conclusion

Based on our study, routine removal of titanium miniplates can be performed in children to avoid growth disturbances, not indicated in adult patients unless symptomatic.

Heparin-mediated antibiotic delivery from an electrochemically-aligned collagen sheet

BACKGROUND

Implantable medical devices and hardware are prolific in medicine, but hardware associated infections remain a major issue.

OBJECTIVE

To develop and evaluate a novel, biologic antimicrobial coating for medical implants.

METHODS

Electrochemically compacted collagen sheets with and without crosslinked heparin were synthesized per a protocol developed by our group. Sheets were incubated in antibiotic solution (gentamicin or moxifloxacin) overnight, and in vitro activity was assessed with five-day diffusion assays against Pseudomonas aeruginosa. Antibiotic release over time from gentamicin-infused sheets was determined using in vitro elution and high performance liquid chromatography (HPLC).

RESULTS

Collagen-heparin-antibiotic sheets demonstrated larger growth inhibition zones against P. aeruginosa compared to collagen-antibiotic alone sheets. This activity persisted for five days and was not impacted by rinsing sheets prior to evaluation. Rinsed collagen-antibiotic sheets did not produce any inhibition zones. Elution of gentamicin from collagen-heparin-gentamicin sheets was gradual and remained above the minimal inhibitory concentration for gentamicin-sensitive organisms for 29 days. Conversely, collagen-gentamicin sheets eluted their antibiotic load within 24 hours. Overall, heparin-associated sheets demonstrated larger inhibition zones against P. aeruginosa and prolonged elution profile via HPLC.

CONCLUSION

We developed a novel, local antibiotic delivery system that could be used to coat medical implants/hardware in the future and reduce post-operative infections.

Complications of Poly-l-Lactic Acid and Polyglycolic Acid (PLLA/PGA) Osteosynthesis Systems for Maxillofacial Surgery: A Retrospective Clinical Investigation

Two second-generation PLLA/PGA bioresorbable osteosynthetic plate systems for oral and maxillofacial surgery are available in Japan. The two systems have different PLLA-PGA component ratios (RapidSorb^®, 85:15; Lactosorb^®, 82:18) and plate and screw shapes. We conducted a retrospective study to compare our clinical evaluation and examine the incidence of postoperative complications between the two plate systems. A retrospective survey was conducted in 148 patients (midfacial fracture/trauma (68.2%) and dentofacial deformity patients (31.8%); males (54.7%); median age, 37.5 years) treated using maxillofacial osteosynthetic plate systems. The complications included plate exposure (7.4%), infection, (2.7%), and plate breakage (0.7%). Multivariate logistic regression analysis showed a significant correlation between sex (female), plate system (Lactosorb^®), number of plates, and pyriform aperture and periorbital sites of plate placement (p < 0.05). Additionally, the propensity score-adjusted model showed a significant correlation between Lactosorb^® and postoperative complications (odds ratio 1.007 (95% confidence interval, 1.001–1.055), p < 0.01). However, the two plate systems showed a low incidence rate of complications, and the plate integration and survivability were similar using 2.0-mm or 1.5-mm resorbable plate regardless of the plate system. Our findings suggest that female sex and a greater number of plates are risk factors for postoperative complications, whereas pyriform aperture and periorbital plate placements reduce the risk.

Is Decreased Local Bone Quality an Independent Risk Factor for Complications Following Fracture Fixation of Facial Bones

PURPOSE

Although osteoporosis is associated with increased risks of complications of fracture fixation in the orthopedic literature, the association between local bone quality (LBQ) and complications of facial fracture fixation is unknown. The authors aim to identify that if decreased LBQ is an independent risk factor for complications following facial fracture fixation?

METHODS

The authors conducted a prospective cohort study on patients over age of 50 years who underwent open reduction and rigid internal fixation for facial fractures. The primary predictor was LBQ (low or normal), decided by a combination of 3 panoramic indices. Other predictors included age, gender, body mass index (BMI), comorbidities, trauma-related characteristics, etc. The outcome variable was the presence of hardware-related, fracture-healing, wound, or neurosensory complications during 2-year follow-up. Univariate and multivariate regressions were performed to identify any significant association between predictor and outcome variables.

RESULTS

The sample was composed of 69 patients (27 females) with an average age of 58.6 ± 8.6 years and BMI of 25 ± 3.8. Low-LBQ patients were significantly older, more females, had lower BMI, mainly injured from falls, had more complications compared to their normal-LBQ counterparts. However, multivariable logistic regressions demonstrated that only age (adjusted OR: 1.12, P = 0.031, 95% CI: 1.01, 1.23) and diabetes (adjusted OR: 12.63, P = 0.029, 95% CI: 1.3, 122.53) were significantly associated with overall complications after confounding adjustment.

CONCLUSIONS

The results of the present study indicate that reduced LBQ is not an independent risk factor for complications following facial fracture fixation. The increased risk of complications in low-LBQ patients is more likely to be attributed to other age-related comorbidities such as diabetes. Therefore, the authors recommend detailed workup and good control of comorbidities in elderly trauma patient.

The healthcare burden and associated adverse events from total alloplastic temporomandibular joint replacement: a national United States perspective

The purpose of this study was to provide a United States perspective on alloplastic total joint replacement. We sought to estimate the inpatient burden and report the most common adverse events using two administrative datasets. The National Inpatient Sample was queried from October 2015 to December 2016 for total joint replacement admissions using International Classification of Diseases 10^th revision codes, and the Manufacturer and User Facility Device Experience registry was queried from January 2009 to September 2019 using manufacturer brands. The combined final sample included 114 inpatient admissions and 392 adverse events. Mean age was 43.1 years, and most patients were white (82.7%) and female (86.0%). The mean hospital charge was $108,709.43 and the mean length of stay was 2.6 days. The most common adverse events were infection (26.3%), heterotopic bone (20.9%), and poor intraoperative fit (14.0%). Fifty-four percent of cases had bilateral total joint replacements, 24.6% had simultaneous subcutaneous abdominal fat grafting, and 11.4% had simultaneous maxillary repositioning. Fat grafting and maxillary repositioning were not associated with any significant difference in the length of stay or cost. Compared to unilateral cases, bilateral total joint replacements carried significantly greater charges (P<0.01), but no increased length of stay (P=0.70), suggesting that bilateral and unilateral cases may experience a similar postoperative course.

A mechanical study of novel additive manufactured modular mandible fracture fixation plates - Preliminary Study with finite element analysis.✰

The paper presents an innovative osteofixation system designed for bone fracture stabilization. Its special feature, which makes it different from other similar systems, is the possibility to precisely adjust the implant to the shape of the bone. Such a precise adjustment is particularly important in the case of multiple fractures, where proper stabilization is a condition for restoring bone geometry and thus obtaining the biomechanical function of a given segment of the body lost due to fracture. Based on the tested properties of the implant material, the presented system structure was verified for loading, stress, and share forces in multi-site fractures of the mandible. Numerical tests were performed for three different fracture models: unilateral double fracture of the body of mandible, unilateral double fracture of the body and the angle of mandible, and bilateral fracture of the mandible at the angle and body of the mandible. The results indicate that the proposed system may be used to stabilize broken bone fragments successfully, and the obtained stabilization would allow unrestricted use of the chewing function during bone healing and remodeling. The authors point out the advantages of the proposed implantation method thanks to which it is possible to obtain any shape of the implant and thus stabilize bone fragments in any case.

The Implications of Titanium Alloys Applied in Maxillofacial Osteosynthesis

Titanium alloys are known for their biological, mechanical and chemical properties, which have successfully expanded their use in the maxillofacial field. The internal fixation using titanium miniplates and screws offer a new perspective for the treatment of trauma and in orthognathic surgery and maxillofacial oncology. Although, titanium is highly recommended for its excellent biocompatibility, recent research has focused on identifying the potential local and general implications of the interactions between the human tissue and the metallic particles. This present review aims to outline the existing tissue changes, cellular alterations and future perspectives regarding the use of titanium-based alloys as osteosynthesis materials, taking into consideration the existing present debate whether the routinely removal of these materials should be an indication.

Miniplate removal in operated cases of maxillofacial region in a dental institute in Rajasthan, India

Background

The long term management of miniplate fixation osteosynthesis remains debatable and controversial with few authors advocating routine removal of the miniplates after 3–6 months of placement, while others recommend retention of the miniplates unless their removal is clinically indicated.

Objective

The aim was to study the incidence, indications, time gap, role of metallic composition and site of removal of miniplates in operated cases of maxillofacial region over a two-year period.

Methods

Patients undergoing removal of miniplates over 2-year period were studied and evaluated regarding the number of miniplates removed, time gap present between fixation and removal of miniplates, indications for removal, metallic composition of miniplates removed, sites of removal and complications. Correlations between indications for miniplate removal based upon time gap, metallic composition, age group and number of miniplates present were determined using Chi-square test. Correlation between metallic composition of miniplate and time gap was also determined using Chi-square test.

Results

The miniplates were removed in 20 patients (16 males and 4 females). Most common indication for removal was infection (45%). Forty-five percent of the patients underwent miniplate removal within 1 year of placement. Thirty-four miniplates and 118 screws were removed. The correlation between indications for miniplate removal and time gap was found to be statistically significant (P = 0.04).

Conclusion

Most of the hardware removal is performed subsequent to complications associated with hardware and local factors play more important role than metallic composition. Routine asymptomatic miniplates do not require removal and is not recommended.

In vivo study of the efficacy, biosafety, and degradation of a zinc alloy osteosynthesis system

In this study, a comprehensive analysis of a novel zinc alloy osteosynthesis system in a canine mandibular fracture model is presented. The efficacy of the system was compared for PLLA (poly-l-lactic acid) and titanium materials using X-ray radiography, micro-CT tomography, undecalcified bone histomorphometry, and a three-point bending test. Histology, blood normal, blood biochemical, and serum zinc concentration tests were also performed to assess the biosafety of the zinc alloy osteosynthesis system. The degradability of the zinc alloy was evaluated using a micro-CT and scanning electron microscope during the 24-week post operation period. The results showed that zinc alloy possesses good mechanical properties that support fracture healing. Its uniform and slow corrosion leads to adequate degradation behavior in 24 weeks. Additionally, the zinc alloy proved to be biocompatible, indicating that this novel osteosynthesis system is safe for use in the body. The results of the study demonstrate that this zinc alloy-based osteosynthesis system is a promising candidate for a new generation of osteosynthesis systems, with further improvements required in the future.

Influence of surface modifications on the degradation of standard-sized magnesium plates and healing of mandibular osteotomies in miniature pigs

Biodegradable magnesium alloys are suitable osteosynthesis materials. Despite the alloy composition, surface modifications appear to have an influence on the degradation process and biocompatibility. The aim of this study was to investigate the impact of hydrogenation and fluoridation of the surface in a mandibular osteotomy model. Standard-sized plates and screws were implanted in an osteotomy at the mandibular angle in nine miniature pigs. The plates and screws were harvested together with the adjacent tissues at 8 weeks after surgery and were investigated by micro-computed tomography and histological analysis. The bone healing of the osteotomy was undisturbed, independent of the surface properties. The adjacent bone tissue showed new bone formation at the implant surface; however, formation of some lacunae could be observed. The corrosion was between 9.8% and 11.6% (fluoridated<hydrogenated<non-modified) in histological specimens, while radiologically neither the volume nor the density of the osteosynthesis material was reduced in any treatment group. The soft tissues exhibited full biocompatibility with every surface property. In summary, surface modification by hydrogenation and fluoridation did not significantly influence bone healing, biocompatibility, or corrosion kinetics of the magnesium osteosynthesis at the mandibular angle.

Investigation of zinc‑copper alloys as potential materials for craniomaxillofacial osteosynthesis implants

In this study, zinc‑copper (ZnCu) alloys were investigated regarding their feasibility as absorbable metals for osteosynthesis implants, especially in the craniomaxillofacial area. Mechanical properties and in vitro corrosion behavior of as-rolled Zn-xCu (x = 1, 2 and 4 wt%) alloys were systematically evaluated and screened. The as-rolled Zn4Cu alloy had mechanical properties that were superior to the most absorbable craniomaxillofacial osteosynthesis materials recently reported. The addition of Cu to Zn showed to have no apparent effect on the corrosion rates of the samples. The rolling process on Zn and Zn1Cu resulted in more uniform corrosion than on as-cast counterparts after 28 days immersion. Furthermore, the Zn4Cu alloys exhibited no apparent cytotoxic effect towards L929, TAg or Saos-2 cells. Proliferation rates of TAg and Saos-2 cells were shown to be activated by specific Zn ion concentrations in the as-rolled Zn4Cu alloy extracts. Analysis of in vitro antibacterial properties revealed that the as-rolled Zn4Cu alloy possessed the potential to inhibit biofilm formation of mixed oral bacteria. We conclude that the as-rolled Zn4Cu alloy might be a promising material for fabrication of craniomaxillofacial osteosynthesis implants.

Osteosynthesis of a cranio-osteoplasty with a biodegradable magnesium plate system in miniature pigs

Biodegradable magnesium alloys are a new class of implant material suitable for bone surgery. The aim of this study was to investigate plates and screws made of magnesium for osteosynthesis in comparison to titanium in a cranial fracture model. Implants were used for internal fixation of a cranio-osteoplasty in nine minipigs. Computed tomography was conducted repeatedly after surgery. The implants and the adjacent tissues were harvested 10, 20 and 30weeks after surgery and investigated by micro-computed tomography and histological analysis. The surgical procedure and the inserted osteosynthesis material were well tolerated by the animals, and the bone healing of the osteoplasty was undisturbed at all times. The adjacent bone showed formation of lacunas in the magnesium group, resulting in a lower bone-to-implant contact ratio than that of titanium (72 vs. 94% at week 30), but this did not lead to clinical side effects. Radiological measurements showed no reduction in osteosynthesis material volume, but indicated signs of degradation: distinct volumes within the magnesium osteosynthesis group had lower density in micro-computed tomography, and these volumes increased up to 9% at week 30. The histological preparations showed areas of translucency and porosity inside the magnesium, but the outer shape of the osteosynthesis material remained unchanged. No fracture or loosening of the osteosynthesis devices appeared. Soft tissue probes confirmed sufficient biocompatibility. Given their biodegradable capacity, biocompatibility, mechanical strength and visibility on radiographs, osteosynthesis plates made of magnesium alloys are suitable for internal fixation procedures.

STATEMENT OF SIGNIFICANCE

To the best of our knowledge this is the first study that used biodegradable magnesium implants for osteosynthesis in a cranial fracture model. The cranio-osteoplasty in miniature pigs allowed in vivo application of plate and screw osteosynthesis of standard-sized implants and the implementation of surgical procedures similar to those conducted on human beings. The osteosynthesis configuration, size, and mechanical properties of the magnesium implants within this study were comparable to those of titanium-based osteosynthesis materials. The results clearly show that bone healing was undisturbed in all cases and that the biocompatibility to hard- and soft tissue was sufficient. Magnesium implants might help to avoid long-term complications and secondary removal procedures due to their biodegradable properties.

Comparison of the long-term clinical performance of a biodegradable and a titanium fixation system in maxillofacial surgery: A multicenter randomized controlled trial

BACKGROUND

Biodegradable fixation systems could reduce or eliminate problems associated with titanium removal of implants in a second operation.

AIM

The aim of this study was to compare the long-term (i.e. >5 years postoperatively) clinical performance of a titanium and a biodegradable system in oral and maxillofacial surgery.

MATERIALS AND METHODS

The present multicenter Randomized Controlled Trial (RCT) was performed in four hospitals in the Netherlands. Patients treated with a bilateral sagittal split osteotomy (BSSO) and/or a Le Fort-I osteotomy, and those treated for fractures of the mandible, maxilla, or zygoma were included from December 2006 to July 2009. The patients were randomly assigned to either a titanium (KLS Martin) or a biodegradable group (Inion CPS).

RESULTS

After >5 years postoperatively, plate removal was performed in 22 of the 134 (16.4%) patients treated with titanium and in 23 of the 87 (26.4%) patients treated with the biodegradable system (P = 0.036, hazard ratio (HR) biodegradable (95% CI) = 2.0 (1.05-3.8), HR titanium = 1). Occlusion, VAS pain scores, and MFIQ showed good and (almost) pain free mandibular function in both groups.

CONCLUSION

In conclusion, the performance of the Inion CPS biodegradable system was inferior compared to the KLS Martin titanium system regarding plate/screws removal in the abovementioned surgical procedures.

TRIAL REGISTRATION

http://controlled-trials.com ISRCTN44212338.