Surgical Repositioning of the Premaxilla: Incidence, Indications and Growth Study About a 189 Bilateral Cleft Lip ± Palate Population

OBJECTIVE

We aimed to evaluate the rate of patient requiring Surgical Repositioning of the Premaxilla in a population carrying BCL  ±  P, retrieve age and operative indication. Our secondary objective was to present further facial growth characteristics.

SETTINGS

This was a retrospective, single-center cohort study conducted in Nantes University Hospital, Oral and Maxillofacial Surgery department, tertiary cleft center.

PATIENTS

Patients with BCL  ±  P born between 1980 and 2019 treated at Nantes University Hospital were included.

MAIN OUTCOME MEASURE

Our primary outcome measure was the rate of patient requiring SRP.

RESULTS

Over the whole period, 189 patients with BCL  ±  P were identified. Three patients (1,58%) underwent SRP. Patients who underwent SRP all had BCLP. SRP was performed during their primary dentition period. The indication for surgical repositioning was always premaxilla vertical overgrowth with an overbite over 10 mm. Facial growth features in the three patients were mostly comparable with a population carrying BCLP who had no premaxillary surgery.

CONCLUSION

Our results showed a low incidence of SRP. No SRP was necessary during early infancy (ie, before lip repair) or during adulthood. Surgical repositioning of the premaxilla is beneficial for patient with orthodontically uncorrectable vertical premaxillary excess, even more since facial development compared with other patients with BCLP appears comparable.

Bone characteristics in condylar hyperplasia of the temporomandibular joint: a microcomputed tomography, histology, and Raman microspectrometry study

Unilateral condylar hyperplasia (UCH) of the temporomandibular joint is a progressive deformation of the mandibular condyle of unknown origin. UCH is characterized by excessive growth of the condylar head and neck, leading to an increase in size and volume. The aim of this study was to investigate the characteristics of the bone in patients with UCH using microcomputed tomography (micro-CT), histology, and Raman microspectroscopy. The mandibular condyles of six patients with UCH were analysed using micro-CT, histology, and Raman microspectrometry and imaging, and the results were compared with those obtained for a normal control subject. Three-dimensional micro-CT models revealed focal abnormalities of the bone microarchitecture, with foci of osteosclerosis. Histological sections showed that these foci included islands of calcified cartilage matrix with live chondrocytes. Raman analysis revealed that the cartilage matrix was more heavily calcified than the bone matrix and that the cartilage could be identified by the phenylalanine (PHE) band of its matrix, as well as by its glycosaminoglycan (GAG) content. The persistence of foci of live and active chondrocytes within the bone matrix is intriguing and appears to be pathognomonic of UCH. These new findings on UCH could help to determine its pathophysiology and thus prevent this disease, which can lead to major facial deformity.

Signature of the vascular tumor microenvironment as a marker of the therapeutic response to doxorubicin in a preclinical model of osteosarcoma

Predicting a response of osteosarcoma patients to chemotherapy, such as doxorubicin or high-dose methotrexate cocktail, remains a challenge in the clinic. Moreover, the prognostic value of currently used necrosis analysis is debatable. New markers of the therapeutic response or the prognostic response are urgently needed. The microenvironment plays a key role in the vascularization of highly heterogeneous tumors. Using the syngeneic MOS-J mouse model of osteosarcoma, we focused our study on the immunohistochemistry of tumor vascularization in order to identify new vessel markers, and to search for potential markers of the therapeutic response. Endomucin+, CD31+, and α-SMA+-positive elements were quantified in control (n=6) and doxorubicin-treated (n=6) mice in three different intra-tumor locations. We also used co-labeling to assess CD31+/Endomucin+ and CD31+/α-SMA+ co-expression. We identified a central tumor zone with a low vascularization profile for all of these markers. We identified two distinct types of vessels: CD31+/Endomucin+ vessels with a sprouting, neo-angiogenic, interlaced appearance, and CD31+/α-SMA+ vessel with a well-defined, mature structure. Doxorubicin appeared to reduce CD31+ expression in the tumor invasion front. In the doxorubicin-sensitive model, there were four times more CD31+/α-SMA+ elements than in the poorly responsive model. Therefore, we propose a methodology based on immunohistochemistry and multiplexed immunofluorescence to use endomucin as a promising new vascular marker in the osteosarcoma model. Moreover, our results suggest that CD31+/α-SMA+ vessels could be considered to be indicators of vasculature normalization and they may be used as specific markers of a good therapeutic response.

Significant decrease of facial cellulitis admissions during COVID-19 lockdown in France: A multicentric comparative study

During the 2020 coronavirus pandemic, a lockdown was imposed in France during the first wave. An apparent decrease in incidence of cellulitis of odontogenic origin was noticed then. This study aimed to compare the incidence of cellulitis during this extraordinary period with the same period in 2018 and 2019, based on retrospective multicentric data. All maxillofacial surgery departments in French public hospitals were contacted. Responders were asked to include all patients admitted for the surgical drainage of a head and neck abscess of odontogenic origin during the first 2020 lockdown period, and in a similar time frame in 2018 and 2019 (control group), based on screening the French diagnostic and therapeutic classification of medical acts. We report a 44% significant nationwide decrease in the incidence of admissions for cellulitis. There were 187 patients in 2020 for 334 and 333 patients in 2018/2019 respectively. The reasons to explain this finding are hypothetical (organizational reasons leading to earlier management, patients' fear to seek for medical management, usual excess in surgical indications or concomitant decrease of non-steroidal anti-inflammatory drugs delivery). Whatever the explanation, it would be of great interest to find it out in order to improve the prevention of cellulitis.

Impact of the COVID-19 lockdown on the epidemiology of maxillofacial trauma activity: a French multicentre comparative study

The coronavirus disease 2019 (COVID-19) outbreak has had a major impact on medical and surgical activities. A decline in facial trauma incidence was noticed during the lockdown period. The aim of this study was to evaluate the decline in maxillofacial trauma in France during this particular period. A retrospective multicentre comparative study was initiated in 13 major French public hospital centres. The incidence of facial trauma requiring surgery during the first month of lockdown was compared to that during equivalent periods in 2018 and 2019. Differences in the types of trauma were also analysed. Thirteen maxillofacial departments participated in the study. A significant decline in maxillofacial trauma volumes was observed when compared to equivalent periods in 2018 and 2019 (106 patients compared to 318 and 296 patients, respectively), with an average reduction of 65.5% (P = 0.00087). The proportion of trauma due to sports and leisure was reduced when compared to reports in the literature. As a consequence, in the context of a pandemic, the material and human resources related to this activity could be reallocated to the management of other pathologies that cannot be postponed.

Conception and use of a custom-made facial mask for pressure therapy in complex facial wounds

Pressure therapy (PT) is commonly used to manage hypertrophic scars. It is often based on the use of elastic pressure garments, which are poorly suited for a facial localization. We describe the conception, fabrication, and use of a custom-made PT facial mask for primary prevention of hypertrophic scarring of complex facial wounds. The main advantage of the device is that it is quick and easy to manufacture in a conventional prosthetics laboratory, with a good level of observance and tolerance in our experience of 20 treated patients.

Fibrous dysplasia of the orbital region: Series of 12 cases and review of the literature

PURPOSE

Fibrous dysplasia (FD) is a benign fibro-osseous developmental disorder of growing bone, sometimes involving the craniofacial skeleton (CFD). We wish to present a patient series with CFD of the orbital region and discuss treatment modalities.

METHODS

Twelve patients were referred for orbital CFD in the Nantes University Hospital between 2000 and 2018 and studied according to the clinical parameters, radiological features, and modalities of treatment.

RESULTS

The mean age was 25.6 years. Ten patients exhibited facial asymmetry with vertical globe dystopia (75%), proptosis (58%) and facial bump (50%). The disease was monostotic in 83% of patients, involving the frontal bone (25%), the sphenoidal bone (33%), the fronto-sphenoidal complex (25%), and the skull base (17%). Unilateral radiological proptosis was found in 7 patients, with a mean protrusion 3.9mm. The optic canal was involved in 75% of patients, with no functional impairment. Three patients were treated with bisphosphonate therapy to stop progression of the disease; 6 patients were given a bone remodelling procedure with good aesthetic outcomes.

CONCLUSION

The orbit is a rare localization for FD causing aesthetic and functional disabilities. Medical and surgical treatment can be proposed as part of a multidisciplinary approach.

Role of mechanical cues and hypoxia on the growth of tumor cells in strong and weak confinement: A dual in vitro-in silico approach

Characterization of tumor growth dynamics is of major importance for cancer understanding. By contrast with phenomenological approaches, mechanistic modeling can facilitate disclosing underlying tumor mechanisms and lead to identification of physical factors affecting proliferation and invasive behavior. Current mathematical models are often formulated at the tissue or organ scale with the scope of a direct clinical usefulness. Consequently, these approaches remain empirical and do not allow gaining insight into the tumor properties at the scale of small cell aggregates. Here, experimental and numerical studies of the dynamics of tumor aggregates are performed to propose a physics-based mathematical model as a general framework to investigate tumor microenvironment. The quantitative data extracted from the cellular capsule technology microfluidic experiments allow a thorough quantitative comparison with in silico experiments. This dual approach demonstrates the relative impact of oxygen and external mechanical forces during the time course of tumor model progression.

Management of maxillofacial trauma in the elderly: A European multicenter study

BACKGROUND/AIMS

Management of maxillofacial trauma in the geriatric population poses a great challenge due to anatomical variations and medical comorbidities. The aim of this study was to analyze the management variables, timing, and outcomes of facial fractures in elderly patients (aged 70 years or more) at several European departments of oral and maxillofacial surgery.

MATERIALS AND METHODS

This study was based on a systematic computer-assisted database that allowed the recording of data from all geriatric patients with facial fractures from the involved maxillofacial surgical units across Europe between 2013 and 2017.

RESULTS

A total of 1334 patients were included in the study: 665 patients underwent closed or open surgical treatment. A significant association (P < .005) was found between the presence of concomitant injuries and a prolonged time between hospital admission and treatment. The absence of indications to treatment was associated with comorbidities and an older age (P < .000005).

CONCLUSIONS

Elderly patients require specific attention and multidisciplinary collaboration in the diagnosis and sequencing of trauma treatment. A prudent attitude may be kept in selected cases, especially when severe comorbidities are associated and function is not impaired.

Surgical management of unilateral body fractures of the edentulous atrophic mandible

INTRODUCTION

Management of body fractures in patients with edentulous atrophic mandibles represents a challenging task due to patient's age, medical comorbidities, poor bone quality, and vascularity, as well as reduced contact area between the fracture ends. The aim of the study was to assess the demographic and clinical variables, the surgical technique, and outcomes of unilateral body fractures of the edentulous atrophic mandible managed at several European departments of oral and maxillofacial surgery.

METHODS

This study is based on a systematic computer-assisted database that allowed the recording of data of all patients with fractures of the atrophic edentulous mandible from the involved maxillofacial surgical units across Europe between 2008 and 2017. The following data were recorded for each patient: gender, age, comorbidities, etiology, synchronous body injuries, degree of atrophy of the mandible according to Luhr classification, type of surgical approach and fixation, length of hospitalization, and presence and type of complications.

RESULTS

A total of 43 patients were included in the study: 17 patients' mandibles were classified as class I according to Luhr, 15 as class II, and 11 as class III. All patients underwent open reduction and internal fixation by extraoral approach in 25 patients, intraoral in 15 patients, and mixed in 3 patients. A single 2.0 miniplate was used in 16 patients, followed by a single 2.4 reconstruction plate in 13 patients, by two 2.0 miniplates, and three 2.0 miniplates. Outcome was considered to be satisfying in 30 patients, with no complications. Complications were observed in 13 cases.

CONCLUSIONS

Treatment of unilateral body fractures of the edentulous mandible must still be based on the type of fracture, degree of atrophy, experience of the surgeon, and patients' preference. An adequate stability can be obtained by different plating techniques that have to be appropriately tailored to every single specific patient.

Management of mandibular condylar fractures in patients with atrophic edentulous mandibles

INTRODUCTION

Treatment of condylar fractures in patients with atrophic edentulous mandibles is a peculiar field that has been little considered in the literature. The aim of the study was to assess the demographic and clinical variables as well as management and outcome of mandibular condylar fractures in edentulous patients with atrophic mandibles that were treated at several European departments of oral and maxillofacial surgery.

METHODS

The data of all patients with fractures of the atrophic edentulous mandible from the involved maxillofacial surgical units across Europe between January 1, 2008, and December 31, 2017. Only patients that were diagnosed with condylar fractures of the edentulous atrophic mandible were included.

RESULTS

A total of 52 patients met the inclusion criteria and were included in the study: 79% of patients reported one or more comorbidities. Thirty-four unilateral neck or subcondylar fractures, 9 bilateral neck or subcondylar condylar fractures, 7 unilateral head condylar fractures, and 2 bilateral head condylar fractures were diagnosed. No treatment was performed in 37 cases, whereas in 4 patients a closed treatment was decided, and 11 patients underwent open reduction and internal fixation. Outcome was considered to be satisfying in 48 patients, with no complications.

CONCLUSIONS

The golden rule still remains that the diagnosis of a subcondylar or neck fracture in an edentulous patient should constitute an indication for open reduction and internal fixation. However, an appropriate choice of management options has to be individualized on a case by case basis, also depending on the patient consent.

Vertical lengthening genioplasty: A new osteotomy technique

Vertical insufficiency of the chin imbalances the orofacial and aesthetic parameters of the lower third of the face. We here propose a new osteotomy technique for chin lengthening. Our procedure is based on a single osteotomy and it does not require any interposition of a bone graft. In our experience with seven patients, we report good aesthetic and morphometric outcomes at one year.

Epidemiology of maxillofacial trauma in the elderly: A European multicenter study

INTRODUCTION

The progressive aging of European population seems to determine a change in the epidemiology, incidence and etiology of maxillofacial fractures with an increase in the frequency of old patients sustaining craniofacial trauma. The objective of the present study was to assess the demographic variables, causes, and patterns of facial fractures in elderly population (with 70 years or more).

MATERIALS AND METHODS

The data from all geriatric patients (70 years or more) with facial fractures between January 1, 2013, and December 31, 2017, were collected. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, etiology, site of facial fractures, synchronous body injuries, Facial Injury Severity Score (FISS).

RESULTS

A total of 1334 patients (599 male and 735 female patients) were included in the study. Mean age was 79.3 years, and 66% of patients reported one or more comorbidities. The most frequent cause of injury was fall and zygomatic fractures were the most frequently observed injuries. Falls were associated with a low FISS value (P<.005). Concomitant injuries were observed in 27.3% of patients. Falls were associated with the absence of concomitant injuries. The ninth decade (P<.05) and a high FISS score (P<.005) were associated with concomitant body injuries too.

CONCLUSIONS

This study confirms the role of falls in the epidemiology of facial trauma in the elderly, but also highlights the frequency of involvement of females, and the high frequency of zygomatic fractures.

Mandibular bone effects of botulinum toxin injections in masticatory muscles in adult

OBJECTIVE

Botulinum toxin (BTX) is injected into masticatory muscles to treat various conditions. Animal studies have demonstrated bone loss at the condylar and alveolar regions of the mandible after BTX injection into masticatory muscles. The aim of the present study was to investigate mandibular bone changes in patients who received BTX injections in masticatory muscles.

STUDY DESIGN

Twelve adult patients who received BTX injections into masticatory muscles were included in this study. Cone beam computed tomography (CBCT) was performed before and 12 months after the injection. The condylar and alveolar regions of the mandible were analyzed by using texture analysis of the CBCT images with the run length method. Condylar cortical thickness was measured, and 3-dimensional analysis of the mandible was also performed. Six patients who did not receive BTX injections were used as controls.

RESULTS

A run length parameter (gray level nonuniformity) was found to be increased in condylar and alveolar bones. A significant cortical thinning was found at the anterior portion of the right condyle. Three-dimensional analysis showed significant changes in the condylar bone and at the digastric fossa. No changes in mandibular angles were found.

CONCLUSIONS

This study identified mandibular bone changes in adult patients who received BTX injection into masticatory muscles.

The "European zygomatic fracture" research project: The epidemiological results from a multicenter European collaboration

PURPOSE

Fractures of the zygomaticomaxillary complex (ZMC) are common injuries that may lead to loss of an aesthetically pleasing appearance and functional impairment. The aim of this study was to analyze the demographics, causes, characteristics, and outcomes of zygomatic fractures managed at several European departments of oral and maxillofacial surgery.

MATERIALS AND METHODS

This study is based on a multicenter systematic database that allowed the recording of all patients with ZMC fractures between 1 January 2013 and 31 December 2017. The following data were recorded: gender, age, personal medical history, etiology, side of zygomatic fracture, classification of ZMC fracture, associated maxillofacial fractures, symptoms at diagnosis, type of performed treatment, and sequelae/complications.

RESULTS

A total of 1406 patients (1172 males, 234 females) were included in the study. Statistically significant correlations were found between assault-related ZMC fractures and the A3 class (p < .0000005) and between Infraorbital Nerve (ION) anesthesia and B class (p < .00000005).

CONCLUSION

The most frequent cause of ZMC fractures was assault, followed by falls. The most frequently involved decade of age was between 20 and 29 years. The decision and type of surgical treatment of ZMC fractures depends on several issues that need to be considered on a case by case basis.

A giant parapharyngeal lipoma causing obstructive sleep apnea

Lipoma is the most common soft tissue mesenchymal neoplasm. Its occurrence is low in the oral cavity (1 to 4%) and in head and neck region (20 to 25%). Usually asymptomatic and slowly growing, lipoma can compress neighboring cervico-facial structures causing dysphagia, dyspnea, or obstructive sleep apnea. We describe an unusual case of giant cervico-parapharyngeal lipoma causing an obstructive sleep apnea in a 69-year-old man and with the complete remove of OSA after surgical procedure.

Associated relaps factors in Le Fort I osteotomy. A retrospective study of 54 cases

PURPOSE

The Le Fort I osteotomy (LFI) procedure is commonly used to restore morpho-functional balance. The goal of maxillofacial surgeons with this procedure is to achieve occlusal stability. To identify factors associated with relapse after maxillary advancement in cleft lip and palate patients, the one-year post-operative stability of Le Fort I osteotomy was evaluated.

METHODS

Horizontal and vertical relapse were analysed on lateral cephalograms by retrospectively using tracing paper in an orthonormal landmark in 54 patients undergoing unilateral cleft lip and palate surgery who were monitored at Nantes University Hospital. The lateral cephalograms were performed pre-operatively, immediately post-operatively, and after one year. Several variables were studied such as population data, intra-operative and post-operative surgical treatment, and surgical movement.

RESULTS

At point A, the subspinale point, the mean advancement during surgery was 4.2 mm, with a relapse of 0.8 mm (20.1%). The mean downward movement was 2.0 mm in 26 patients who had a clockwise rotation of the maxilla, with a relapse of 0.6 mm (28.4%). The mean upward movement was 2.3 mm in 27 patients who had a counterclockwise rotation, with a deterioration of 0.2 mm (7%). A 7-millimetre surgical advancement corresponded to the threshold value beyond which relapse appeared to be significantly greater but still less than two millimetres in 75% of cases.

CONCLUSION

The degree of advancement appears to be the only variable correlated with the amplitude of the relapse.

About a pediatric facial trauma

Less-lethal weapon are more and more used in law enforcement to neutralize combative individuals and to disperse riot crowds. Even if this type of weapon has been created to be less damaging than classical firearms, it has been incriminated many times in cases of facial injuries with functional consequences, even death. In many countries, these guns can be possessed by average citizens. They could be extremely harmful when handled by inexperienced users and cannot be considered solely as defense weapons. Interestingly, little literature is available concerning facial injuries caused by the less-lethal weapons. We report the case of a ballistic wound on a 3-year-old child.

Assessing the effectiveness of botulinum toxin injections into masticatory muscles in the treatment of temporomandibular disorders

Introduction: Temporomandibular disorders (TMD) are a common and invalidating disease sometimes difficult to treat. Current international recommendations favour reversible and non-invasive treatments, including the injection of botulinum toxin (BTX) into masticatory muscles. There is no strong evidence of its effectiveness. Objective: The main goal of this study was to assess the effectiveness of BTX six months following injection, in terms of pain, mouth opening, improvement of symptoms and duration of effect. Materials and methods: A retrospective study carried out at Nantes University Hospital between 2014 and 2016. Results: Thirty-four patients were included. The mean age was 37 years (17–76) and seventy six percents were female. Eighty percent of patients reported a significant improvement, notably in cases of arthralgia, which decreased in 8/18 (44%) patients (p < 0.05). The mean duration of measured efficacy was 4.2 months. Discussion: Significant improvement in cases of arthralgia and a tendency for improvement in cases of myalgia, with a mean duration of action of 4.2 months. Although BTX injection do not guarantee complete resolution of myofascial pain, it have been shown to have beneficial effects on some symptoms have been shown. Conclusion: Botulinum toxin should be considered as an alternative treatment when other conservative methods fail to yield satisfactory results. A thorough multicentre assessment is necessary in the future to scientifically validate its use.

Skeletal unit construction of rat mandible based on the masticatory muscle anatomy and double microcomputed tomography

This study aimed to divide the mandible into skeletal units based on three-dimensional (3D) muscular anatomy with microcomputed tomography (micro-CT) of Sprague-Dawley rat. Five normal rats were micro-CT scanned at 12 weeks of age before and after contrast enhancements for the masticatory muscles. Three-dimensional reconstruction of the mandible was performed from the initial micro-CT images, followed by segmentation of the masticatory muscles using the second enhanced micro-CT data. Bone and muscle models were superimposed based on the teeth and bony structures to evaluate muscular orientation and attachment. The mandible was divided into skeletal units using the bony structures and muscle attachments. The mandibular foramen and mental foramen were adopted as the reference points based on their anatomical and developmental significance. The skeletal units consisted of the condylar, coronoid, angular, body and symphyseal units. Further evaluation of these units in relation to development, growth, and other biology and medicine will be helpful in elucidating their biological identities.

Familial autosomal dominant severe ankyloglossia with tooth abnormalities

Ankyloglossia is a congenital oral anomaly characterized by the presence of a hypertrophic and short lingual frenulum. Mutations in the gene encoding the transcription factor TBX22 have been involved in isolated ankyloglossia and X-linked cleft palate. The knockout of Lgr5 in mice results in ankyloglossia. Here, we report a five-generation family including patients with severe ankyloglossia and missing lower central incisors. Two members of this family also exhibited congenital anorectal malformations. In this report, male-to-male transmission was in favor of an autosomal dominant inheritance, which allowed us to exclude the X-linked TBX22 gene. Linkage analysis using short tandem repeat markers located in the vicinity of LGR5 excluded this gene as a potential candidate. These results indicate genetic heterogeneity for ankyloglossia. Further investigations with additional families are required in order to identify novel candidate genes.

Surgical management of lower lip pits in Van der Woude syndrome

Van der Woude syndrome (VDWS) is characterized by the presence of lower lip pits which may be of concern to patients due to aesthetic considerations. By presenting three clinical cases, we provide an overview of the surgical techniques currently available to treat labial pits. Fusiform excision with dissection of the entire pit is still the most commonly used procedure and it generally yields good functional and aesthetic outcomes. The split-lip advancement technique and the inverted T-lip reduction nonetheless represent good surgical alternatives. Proper management of the lower pits that occur with VDWS requires thorough knowledge of the available surgical procedures.

Vertical ramus elongation and mandibular advancement by endobuccal approach: Presentation of a new osteotomy technique

INTRODUCTION

Several surgical procedures have been proposed for the treatment of hyperdivergent dentoskeletal deformities. We propose a new osteotomy technique allowing for lengthening and advancement of the mandibular ramus by intra-oral approach.

SURGICAL PROCEDURE

This technique differs from the conventional sagittal split osteotomyin that which the anterior osteotomy line is not continued until the basilar edge but stopped 5-6mm above it. Cutting of the pterygomasseteric sling is systematically done allowing for the lowering of the mandibular angle. Osteosynthesis is performed by transjugal and intra-oral approaches, using two adjustable miniplates. Our supra-angular technique allows for both elongation of the ramus and advancement of the mandible. Unlike the vertical ramus osteotomy proposed by Caldwell-Letterman, external incision and intraoperative cervical hyperextension are not required.

Design of metallic nanoparticle gratings for filtering properties in the visible spectrum

Plasmonic resonances in metallic nanoparticles are exploited to create efficient optical filtering functions. A finite element method is used to model metallic nanoparticle gratings. The accuracy of this method is shown by comparing numerical results with measurements on a two-dimensional grating of gold nanocylinders with an elliptic cross section. A parametric analysis is then performed in order to design efficient filters with polarization dependent properties together with high transparency over the visible range. The behavior of nanoparticle gratings is also modeled using the Maxwell-Garnett homogenization theory and analyzed by comparison with the diffraction of a single nanoparticle. The proposed structures are intended to be included in optical systems that could find innovative applications.