The coronoid process for paranasal augmentation in the correction of midfacial concavity

Tunneled Paranasal Augmentation Using Diced Autologous Costal Cartilage in Asian Rhinoplasty: A Comparative Study

Due to the prevalence of anterior maxilla dysplasia in Asian population, paranasal concavity is a common accompaniment to low nose, but its impact on facial harmonization is often underestimated. A retrospective comparative study was conducted on patients diagnosed as low nose with paranasal concavity between June 2017 and June 2021, with a total of 56 patients followed up successfully. The control and observation groups were established according to whether the paranasal augmentation was performed. Demographic data were collected. Cosmetic enhancement was quantitatively evaluated by sagittal planimetry, establishing related anatomical landmarks and measuring columella base prominence (CBP) and alar base prominence (ABP). Subjective evaluation concluded the patient-reported satisfaction (FACE-Q-Rhinoplasty Module and Facial Appearance Module) and the third-party physician assessment (Global Aesthetic Improvement Scale, GAIS).Significant improvements in CBP and ABP were reported both in the control and the observation group (p < 0.01). In postoperative intergroup comparisons, the observation group was superior to the control group regarding ABP values (2.5 ± 0.75 degrees, p < 0.01), FACE-Q-Facial scores (7.49 ± 3.70, p < 0.05), and GAIS scores (p < 0.05). However, no statistical difference was found in CBP values and FACE-Q-Rhinoplasty scores. Paranasal augmentation-related complications included asymmetry of alar bases (6.9%) and facial or intraoral foreign body sensation (34.5%). This study affirmed that paranasal augmentation using diced costal cartilage in rhinoplasty is a safe procedure effective in remedying paranasal concavity and improving facial satisfaction. LEVEL OF EVIDENCE::  IV.

Application of Paranasal Augmentation Rhinoplasty in Asians With Midfacial Concavity

BACKGROUND

For Asian rhinoplasty patients with midfacial concavity, the conventional method is to solve the problem by using structural rhinoplasty to increase the nasal height and length. However, the results are not satisfying, and many complications are caused.Paranasal augmentation as an adjunct to rhinoplasty can improve surgical results and increase satisfaction. However, there are limited studies focusing on the details and evaluation of this technique.

OBJECTIVES

To investigate a minimally invasive method to correct midfacial concavity simultaneously with rhinoplasty, as well as improve satisfaction and reduce complications.

MATERIALS AND METHODS

Between January 2010 and December 2019, we reviewed all rhinoplasty patient records from patients who had midfacial concavity and underwent simultaneous paranasal augmentation with our technique. The patient demographics, surgical characteristics, and outcomes were reviewed retrospectively. Satisfaction was evaluated by an independent medical staff who reviewed the preoperative and postoperative photos.

RESULTS

Sixty-seven patients were included in the study. The mean age of the patients was 28.7 ± 8.0 years, and the median follow-up time was 26 months (range, 2-60 months). Overall satisfaction was high (90%). Eight (12%) patients had complications, including 5 (7.4%) cases of implant displacement and 3 (4.4%) cases of infection. All patients healed uneventfully after revision surgery.

CONCLUSIONS

Paranasal augmentation can improve the outcome and increase satisfaction in Asian rhinoplasty patients who have midfacial concavity. Preoperative patient evaluation, surgery planning, and surgery details are crucial to ensure a favorable result. The expanded polytetrafluoroethylene implant has advantages over other materials and therefore is recommended in paranasal augmentation surgery.

Nasolabial Sulcus Rejuvenation: Paranasal Augmentation Using a Folded Dermal Graft

BACKGROUND

Nasolabial sulcus rejuvenation is steadily gaining popularity among Asians. Though many treatment options using synthetic grafts and autografts have been introduced, none of them has yet been accepted as an ideal technique. This study describes the operative procedure and evidence-based clinical outcomes of paranasal augmentation using dermal grafts.

METHODS

From March 2015 to August 2019, 56 patients underwent paranasal augmentation. The dermal graft, harvested from the buttock, was folded into 4 to 6 layers and inserted into the supraperiosteal pocket through a gingivobuccal incision. Ultrasonographic evaluation was performed at postoperative months 1, 6, 12, and 18 to appraise the change in the thickness of the graft.

RESULTS

No major complications, including foreign body sensation and graft extrusion, occurred. The average dermal thickness was 10.31 mm at postoperative month 1 and 6.30 mm, 5.21 mm, and 5.17 mm at postoperative months 6, 12 and 18, respectively. The average absorption rates were 38.72%, 49.36%, and 49.92% at postoperative months 6, 12, and 18, respectively.

CONCLUSIONS

Paranasal augmentation using a folded dermal graft serves as a useful method to rejuvenate the midface with durable and aesthetically satisfactory outcomes. By virtue of biocompatibility, complications occurred rarely compared with the artificial implants.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Comparative Study of the Effect of Paranasal Augmentation With Autologous Bone in Orthognathic Surgery

PURPOSE

The purpose of the present study was to compare the effectiveness of the 3 orthognathic surgical options among the patients who had had mandibular prognathism with a concave midfacial profile.

PATIENTS AND METHODS

A total of 72 patients with mandibular prognathism with a concave midfacial profile were divided into 3 groups. We compared the lateral profile changes using lateral cephalograms. The images were taken before surgery (T0) and at least 6 months to 1 year after surgery (T1). After computerization of the preoperative cephalograms (T0), the surgical changes (T1 minus T0) were measured by computerizing the postoperative cephalograms. Group 1 (n = 21) had undergone bilateral sagittal split osteotomies, group 2 (n = 36) had undergone bilateral sagittal split osteotomy with autologous bone paranasal augmentation, and group 3 (n = 15) had undergone bilateral sagittal split osteotomies and Le Fort I osteotomy.

RESULTS

After surgery, all the landmarks and values showed changes. Among them, quantitative changes could be observed in all the cheek points and cheek lines. The average of the overall cheek points had increased by ∼0.56 mm in group 1, ∼1.85 mm in group 2, and ∼2.39 mm in group 3, horizontally.

CONCLUSIONS

The results of the present study suggest approximately comparative values among the 3 surgical options for patients and surgeons considering orthognathic surgery. In addition, autologous bone paranasal augmentation can be considered as an alternative for Le Fort I osteotomy in specific conditions.

The Inverted Coronoid-Ramus Graft for Condylar Reconstruction

The purpose of this article is to describe a creative, versatile technique for condylar reconstruction using autogenous mandibular bone. The technique has been used for reconstruction of small condyle and/or ramus defects (approximately 35 to 40 mm in length) typically associated with condylar hyperplasia, condylar tumors, idiopathic condylar resorption, and failed reconstruction attempts. The technique involves excision of the ipsilateral coronoid process-mandibular ramus, inverting it and rotating the segment 180° along its horizontal axis to replace the excised condyle. The resultant graft simulates the morphology of the posterior aspects of the ramus and condyle and has been shown to resist resorption typical of endochondral bone grafts harvested from the rib or iliac crest. Grafting is carried out via vestibular and preauricular or endaural incisions. Four cases followed over a period of 3 to 40 months (average, 21 months) are presented. No adverse functional results, including ankylosis, removal of hardware or adverse remodeling, have occurred. A period of intermaxillary fixation is used because it is considered beneficial for intra-articular scarring of the subglenoid fossa pad (disc or retrodiscal tissue and fibrocartilage) and initial healing. Physical therapy has not been prescribed. The inverted coronoid graft is a versatile technique when virtual surgical planning is used to assess feasibility, as well as defect and graft dimensions; fabricate custom bone plate and drilling guides; and determine screw osteosynthesis sites. In general terms, a post-reconstruction opening of 35 mm allows for adequate function and guards from contralateral symptomatic hypermobility given disparate right- and left-sided joint mechanics. In the cases described, a mean of 40.5 mm was achieved; however, in 2 of these cases, this was measured with undesirable asymptomatic (preoperative) deviation to the ipsilateral side by greater than 4 mm and by 6 mm. The inverted coronoid graft technique reduces operative time, can be executed with few external scars, and reduces the number of operative fields.

Alternative intraoral donor sites to the chin and mandibular body-ramus

Background

Provide a review of alternative intraoral donor sites to the chin and body-ramus of the mandible that bring fewer complications and that may be used to regenerate small and medium defects.

Material and Methods

A review was conducted using the search engine PUBMED and looking manually into scientific journals.

Results

From the 35 articles included, 6 corresponded to the coronoids, 3 corresponded to the zygomatic body, 5 corresponded to the anterior maxillary sinus wall, 3 corresponded to the zygomatic alveolar process, 2 corresponded to the incisive fossa, 2 corresponded to the anterior nasal spine, 2 corresponded to the palatal region, 5 corresponded to the tuberosity, and 7 corresponded to the palatal and mandibular tori.

Conclusions

Although there are few complications described when using alternative intraoral donor sites, the main problem with these types of grafts is their scarce bone volume, with only the zygomatic body, anterior sinus wall, and palate sites being able to be used in medium defects. More clinical trials are necessary in order to evaluate the behavior of the alternative donor sites over time. Key words:Grafting, autologous bone, autografts, mandible, maxilla, palate hard, zygoma.

Cone-beam computed tomography evaluation of the maxillofacial features of patients with unilateral temporomandibular joint ankylosis undergoing condylar reconstruction with an autogenous coronoid process graft

Objective

To evaluate the changes in the jaws and the upper airways of unilateral temporomandibular joint ankylosis patients who underwent condylar reconstruction via autogenous coronoid process grafts using cone-beam computed tomography (CBCT).

Study design

The 27 included patients underwent CBCT examinations at three stages: T0 (within two weeks before surgery), T1 (two weeks after surgery), and T2 (an average of 13 months after surgery). Forty items related to the maxillofacial hard tissues and the upper airway collected at the three times and the coronoid process graft volumes after surgery were compared.

Results

Some integral items related to the mandibular hard tissues exhibited statistical difference shortly after surgery. Some integral items related to maxillofacial hard tissues changing obviously long period after surgery may result from graft remodeling. Asymmetry-related item regarding local neo-condyle and some airway items were significantly different between T0 and T1. Due to variations in graft remodeling, some related local asymmetry items and airway items differed significantly between T0 and T2.

Conclusions

Anteriorly and inferiorly located neo-condyles and a trend toward the pronation of the mandible were observed and the narrowness of the upper airway was improved shortly after surgery. The grafts remodeled differently and some integral and asymmetry items related to neo-condyle changed. The improvements in the upper airway were slightly reduced.

Re-Assessment of Coronoid as a Graft for Condylar Reconstruction in TMJ Ankylosis Patients: A Prospective Study and Literature Review

INTRODUCTION

Treatment for TMJ ankylosis aims at restoring joint function, improving the patient's aesthetic appearance and quality of life and preventing re-ankylosis. To rebuild a structurally and functionally satisfactory neocondyle is a challenging problem. Aim of this study is to re-assess the coronoid as a graft for condyle reconstruction.

MATERIALS AND METHODS

Twenty patients of TMJ ankylosis without involvement of the coronoid process in ankylotic mass, coming in age group elder than 14 years were selected for the study over a period 3 years from 2011 to 2014. Clinical examination, radiographs, and photographs were used postoperatively to evaluate the grafts and TMJ function. After osteoarthrectomy coronoid process was detached and fixed with a 4 hole L-shaped titanium miniplate to form neo condyle.

RESULT

No donor site morbidity was observed as reported with other autogenous grafts. Satisfactory mouth opening was observed during follow up period with mean mouth opening 37.33 ± 4.20 mm except one case which required graft removal due to postoperative infection. Radiographically moderate amount of resorption of grafted coronoid process was observed in nearly all the cases however satisfactory mandibular function and occlusion was observed.

Silicone Implant-Based Paranasal Augmentation for Mild Midface Concavity

Background

Midface concavity is a relatively common facial feature in East Asian populations. Paranasal augmentation is becoming an increasingly popular procedure for patients with mild concavity and normal occlusion. In this study, we evaluate clinical outcomes following a series of paranasal augmentation.

Methods

A retrospective review was performed for patients with Class I occlusion who had undergone bilateral paranasal augmentation using custom-made silicone implants, between October 2005 and September 2013. Patient charts were reviewed for demographic information, concomitant operations, and postoperative complications. Preoperative and postoperative (1-month) photographs were used to evaluate operative outcome.

Results

The review identified a total of 93 patients meeting study criteria. Overall, aesthetic outcomes were satisfactory. Five-millimeter thick silicone implant was used in 81 cases, and the mean augmentation was 4.26 mm for this thickness. Among the 93 patients, 2 patients required immediate implant removal due to discomfort. An additional 3 patients experienced implant migration without any extrusion. Nine patients complained of transient paresthesia, which had resolved by 2 weeks. There were no cases of hematoma or infection. All patients reported improvement in their lateral profile and were pleased at follow-up. Complications that arose postoperatively included 9 cases of numbness in the upper lip and 3 cases of implant migration. All cases yielded satisfactory results without persisting complications. Sensations were fully restored postoperatively after 1 to 2 weeks.

Conclusion

Paranasal augmentation with custom-made silicone implants is a simple, safe, and inexpensive method that can readily improve the lateral profile of a patient with normal occlusion. When combined with other aesthetic procedures, paranasal augmentation can synergistically improve outcome and lead to greater patient satisfaction.

Applications of coronoid process as a bone graft in maxillofacial surgery

The coronoid process can be easily harvested as a donor bone by an intraoral approach during many maxillofacial surgery procedures. The purpose of this study was to evaluate the utility of autogenous coronoid process bone grafts for maxillofacial reconstructive surgery. Twelve patients, who underwent coronoid process grafts for reconstruction of maxillofacial deformities due to trauma, alveolar atrophy, or temporomandibular joint ankylosis, were included in the study. There were 3 orbital defects after extended maxillectomy, 1 blowout fracture of the orbit, 2 cases of reconstruction after temporomandibular joint ankylosis surgery, 1 case of additional chin augmentation following horizontal flip genioplasty, 1 defect of anterior wall of maxilla due to trauma, 2 mandibular defects, and 2 cases of bone augmentation for implants.We recommend the use of coronoid process of the mandible as a source for autogenous bone graft as it can provide sufficient bone in quantity and quality for selected maxillofacial reconstructions.

Closure of large oroantral communication using coronoid process pedicled on temporalis muscle flap: a new alternative approach

Proximity of maxillary molar teeth roots to the maxillary sinus floor can potentiate oroantral communication (OAC) after extraction. Considering the defect size and situation, surgical treatment may become essential. Surgical treatment modalities are variable and would be indicated in special clinical circumstances.In this article, a chronic case of OAC with a size of 25 × 15 mm(2) in a 30-year old man with history of heavy smoking and drug abuse was treated with combination of buccal fat pad (for covering sinus floor), coronoid process pedicled on temporalis flap, and mucosal closure. There was no complication during and after operation. Short- and long-term follow-up revealed success of this novel technique despite the patient's poor compliance.

[Le Fort I osteotomies combined with post-operative bone grafts]

INTRODUCTION

We present and assess a surgical technique for maxillary auto-bone grafting concomitantly with Le Fort I osteotomy. The graft has 2 main objectives: to fill in the space between the 2 advanced segments of the maxilla to help bone consolidation, and to increase the volume of the malar, para-nasal spaces to improve post-operative esthetic results.

TECHNICAL NOTE

Bone fragments, removed during the Le Fort I osteotomy, are stored and wrapped in a Surgicel(®) sheet, then grafted in the space left by the osteotomy, or on the anterior maxilla in the para-nasal area or on the malar bone. One hundred and twenty-three patient records, operated from 2007 to 2012, were collected to assess the post-operative course retrospectively. The post-operative course was uneventful in 93.5% of cases. About 8.4% of patients (7 cases) presented with a persistent post-operative maxillary edema. 1 patient (1.2%) presented with a sinus infection without any determined etiology. The grafts were all osteointegrated at the end of follow-up.

DISCUSSION

The technique is simple and quickly performed; it improves bone healing and cosmetic results, without increasing morbidity or surgical time. It is a good alternative to bone grafts from a secondary sample site. It can be applied to all Le Fort I osteotomies.

Comparison of intraoral harvest sites in the edentulous versus dentate specimen

OBJECTIVE

The aim of this study was to compare the edentulous vs dentate specimen intraoral bone harvest sites. We wished to identify if there were any sites that yielded similar quantities of bone regardless of the status of the dentition.

STUDY DESIGN

There were 59 cadavers in the study. Three continuous outcomes (area, thickness, and volume) were measured for each cadaver at 4 sites (zygoma, symphysis, ramus, and coronoid).

RESULTS

Status of the dentition was not a factor in the quantity of harvested bone in regard to surface area and volume. The only difference noted between the dentate and edentulous groups was the thickness in the symphysis and zygomaticomaxillary buttress, with the dentate group, on average, having greater thickness.

CONCLUSIONS

There appeared to be similar amounts of bone available in dentate and edentulous specimens in our study. This information should encourage clinicians to consider intraoral bone harvest for augmentation of an edentulous ridge regardless of the status of the dentition.

Correction of midface hypoplasia using a novel trapezoidal osteotomy

BACKGROUND

Currently, investigating an optimal method to deal with midface hypoplasia has become a significant issue in the field of facial aesthetic surgery. Traditional ways to address this problem primarily include segmental osteotomies and using autogenous bone or cartilage grafts or synthetic implants. For the patients with paranasal hypoplasia but without malocclusion, autogenous bone grafts or implants are recommended. However, some of these patients have a flattened nose and protrusive malar, especially in the Eastern Asian; the nose will seem more flattened after augmentation the paranasal area. Hence, osteotomy is necessary in these patients to bring the flattened nose forward to get a more satisfying contour of the midface.

METHODS

We propose a novel osteotomy through the application of model surgery to solve the problem of midface hypoplasia combined with flattened nose but without malocclusion. When compared with other techniques, this novel method not only allows the augmentation to be performed on a broader scale composed of different segments of the midface skeleton, but also results in a lower surgical risk and maintenance of the stability of occlusion.

RESULTS

This novel osteotomy can bring the premaxilla in combination with the nasal bone forward to solve the problem of midface hypoplasia combined with flattened nose in patients with normal occlusion.

CONCLUSIONS

Through simultaneous augmentation of the different segments of the midface through this novel osteotomy, a more pleasing contour of the midface in all 3 dimensions can be achieved.

Midfacial soft-tissue changes after mandibular setback surgery with or without paranasal augmentation: cone-beam computed tomography (CBCT) volume superimposition

The aim of this article is to compare the soft-tissue changes in the midfacial areas of patients who had undergone mandibular setback sagittal split ramus osteotomy (SSRO) with that of mandibular setback SSRO with paranasal augmentation. The subjects included 15 patients (group I), SSRO with paranasal augmentation and 20 patients (group II), SSRO alone. To evaluate the difference of the midfacial soft-tissue changes between groups, cone-beam computed tomography superimposition was utilized and the soft-tissue changes were measured both preoperatively and postoperatively by a 10 × 27 grid. In group I, the soft tissues were changed at the areas bounded superiorly by the infraorbital foramen, zygomatic eminence, posteriorly by the masseteric muscle and medially by the lateral aspect of the nose and following the nasolabial fold. In group II, the midfacial soft-tissue measurements were unchanged. This study may help clinicians to predict improvement in the midfacial region from mandibular setback SSRO with or without a paranasal augmentation procedure in class III deformities.

Autogenous grafts for condylar reconstruction in treatment of TMJ ankylosis: current concepts and considerations for the future

Temporomandibular joint (TMJ) ankylosis is characterized by difficulty or inability to open the mouth due to fusion of the temporal and the mandible, resulting in facial symmetry/deformity, malocclusion and dental problems. The only treatment option for TMJ ankylosis is surgical with or without condylar reconstruction. Various autogenous grafts are available for condylar reconstruction after freeing the ankylotic mass such as costochondral, sternoclavicular, fibular, coronoid, and metatarsophalangeal. Costochondral graft is preferred by surgeons, but distraction osteogenesis is slowly gaining popularity and may ultimately become the standard procedure, providing a cost-effective approach with low morbidity and excellent functional outcomes. Tissue engineering is another budding field which has shown promising results in animal studies but has not been applied to humans. To date, there is no ideal autogenous graft for condylar reconstruction that satisfies the complex anatomy and the myriad of functions of a missing condyle.

Bone grafting the mandible

Many bone grafting techniques have been used to reconstruct the partially dentate and edentulous mandible. This article discusses the various bone grafting techniques to reconstruct mandibular defects. Also included are issues such as whether autogenous bone is necessary for reconstruction of the mandibular ridge and the importance of membranes.

Bone grafting the mandible

Many bone grafting techniques have been used to reconstruct the partially dentate and edentulous mandible. This article discusses the various bone grafting techniques to reconstruct mandibular defects. Also included are issues such as whether autogenous bone is necessary for reconstruction of the mandibular ridge and the importance of membranes.

Bone graft harvesting from regional sites

Bone grafts are widely used in the reconstruction of osseous defects in the oral and maxillofacial region. Successful osseointegration of dental implants requires sufficient bone surrounding the implant. Although bone substitutes and augmentation techniques offer viable prognoses for achieving the required amount of hard tissue augmentation, autologous bone is the gold standard with regard to quantity, quality, and an uneventful healing. Autogenous bone grafts are generally obtained from the ilium, the rib, and the calvarium. Alternative sources for local harvesting in the mandible can be evaluated by careful clinical and radiographic examinations of the patient. This article discusses the various sources of grafts and the techniques used to harvest bone.

Mandibular ramus/coronoid process grafts in maxillofacial reconstructive surgery

PURPOSE

To evaluate the utility of autogenous extended mandibular ramus and coronoid process bone grafts for maxillofacial reconstructive surgery.

PATIENTS AND METHODS

Twelve patients aged 23 to 76 years (mean, 52) who underwent extended ramus/coronoid process grafts for reconstruction of maxillofacial deformities due to trauma, alveolar atrophy, or iatrogenic nasal deformity. All patients had either unilateral or bilateral combined coronoid process-mandibular ramus bone grafts for their reconstruction. There was 1 nasal reconstruction, 2 unilateral mandibles, 1 bilateral mandible, 4 unilateral maxillas, 1 unilateral maxilla and mandible combined, and 1 bilateral maxilla and mandible combined.

RESULTS

The procedure was considered a success when the patient's deformities were reconstructed ad integrum and when there were no failures of the dental implants placed in the augmented areas as of the longest follow-up. All patients were successfully reconstructed. There was 1 infection at a donor site that resolved with local care and oral antibiotics. All but 1 of the maxillary and mandibular alveolar augmentations underwent endosteal implant placement approximately 4 to 6 months following grafting. The nasal reconstruction restored normal function and symmetry.

CONCLUSION

Using both the coronoid process of the mandible and the mandibular ramus as a source for autogenous bone graft can provide sufficient bone in quantity and quality for selected maxillofacial reconstructions.

Free grafting of autogenous coronoid process for condylar reconstruction in patients with temporomandibular joint ankylosis

OBJECTIVE

This article describes the clinical effects of condylar reconstruction by free grafting of autogenous coronoid process in patients with temporomandibular joint (TMJ) ankylosis.

STUDY DESIGN

Fifteen cases of uni- or bilateral TMJ ankylosis during a 3-year period from March 2004 to March 2007 were surgically treated, and the average observation period was 22 months. All patients were treated by condylar reconstruction of immediate autogenous coronoid process grafts. Temporal muscle myofascial flaps or native articular disc was used as an interpositional tissue. Clinical examination, radiographs, and photographs were used postoperatively to evaluate the grafts and TMJ function.

RESULTS

Satisfactory mouth opening was achieved in 14 cases, and 1 patient showed signs of reankylosis of the joint (20 mm mouth opening). Radiographic examination showed that bone union occurred between the grafts and the ramus in all cases. Some bony resorption of the grafted coronoid process was observed in all patients, but no occlusal changes were noted.

CONCLUSION

Satisfactory clinical outcomes are obtained after the condylar reconstruction by free grafting of autogenous coronoid process. Therefore, autogenous coronoid process may be a suitable bone resource for condylar reconstruction in patients with TMJ ankylosis.

Autogenous coronoid process as a new donor source for reconstruction of mandibular condyle: an experimental study on goats

OBJECTIVE

To evaluate the feasibility and effectiveness of autogenous coronoid process grafts for reconstruction of the mandibular condyle.

STUDY DESIGN

Two groups of 9 goats each were used. Each animal underwent unilateral total condyle and disk removal and was treated by grafting an autogeneous coronoid process. The animals in group A were sacrificed at 4, 12, and 24 weeks after surgical procedure, and their grafted coronoid processes were harvested for histological observation. All animals in group B received 3-dimensional CT scanning examination at different times and were sacrificed at 24 weeks after surgical procedure. The items of ramus height (RH), transverse dimension of the condyle (CT), and posteroanterior dimension of the condyle (CP) were measured for comparison with the operated and nonoperated sides.

RESULTS

Despite the differences in the measurements of RH, CT, and CP between the operated and nonoperated sides, the grafted coronoid process had a similar shape and histological structures to the normal condyle at 24 weeks after surgical procedure. The head of the neocondyle was covered by a cap of fibrous tissue, which might play the role of the articular disc.

CONCLUSIONS

Under the mechanical stimuli of the temporomandibular joint site, the grafted coronoid process could gradually remodel to a neocondyle with functional shape and structure in goats. This animal study suggests that autogenous coronoid process could be considered as a new donor source for reconstruction of the mandibular condyle.

The medial surface of the mandible as an alternative source of bone grafts in orthognathic surgery

A technique of harvesting bone grafts from the medial surface of the angle of the mandible during a bilateral sagittal split osteotomy procedure is described. In 20 patients who underwent mandibular setback for the correction of class III dentofacial deformities, bone grafts were harvested from the medial mandibular angle and used for simultaneous augmentation of the midface or for interpositioning and stabilization of the maxilla after LeFort I maxillary anterior or inferior repositioning. The mean postoperative follow-up was 6 months (range, 3-12 months). No complications occurred, and postoperative morbidity was similar to that encountered by patients who undergo sagittal split osteotomy without bone harvest. The technique described shows that the medial mandibular angle is a suitable donor site for membranous bone grafts in patients who undergo sagittal split osteotomy.

The zygomatic bone as a potential donor site for alveolar reconstruction--a quantitative anatomic cadaver study

The aim of this cadaver study was to evaluate the possibility of using the zygomatic bone as an intraoral bone harvesting donor site and to determine the safety of this harvesting procedure. In addition, the volume of bone material harvested from the zygomatic bone was measured. Twenty fixed adult cadavers were used to yield a total of 40 zygomatic bone harvest sites, from which bone was collected. The volume of bone obtained from the zygomatic harvests was measured with a water displacement method and by compressing the graft into a syringe. The safety of the technique was evaluated by assessing possible encroachment upon the neighbouring structures. After bone harvesting, the zygomatic sites were exposed and evaluated for visible perforations or fractures. Possible damage to the neighbouring tissues was also examined with computed tomography scans at 18 sites in nine cadavers. The average bone graft volume obtained from the zygomatic bone was measured to be 0.53 ml (SD 0.25) with water displacement and 0.59 ml (SD 0.26) with the syringe. The complications in the zygoma included 15 small perforations into the maxillary sinus and 7 perforations into the infratemporal fossa. CT scans showed that bone could be harvested safely without encroaching upon the orbital floor or the surrounding nerves and vessels in the zygoma. The zygomatic bone is a safe intraoral donor site for the reconstruction of small- to medium-sized alveolar defects.

The ascending ramus of the mandible as a donor site in maxillofacial bone grafting

PURPOSE

The goal of this study was to quantify the amount of bone graft material present in the anterior part of ascending ramus while avoiding the inferior alveolar neurovascular bundle injury.

MATERIALS AND METHODS

This study was made on 16 samples of dry skull. Osteotomies were made in front of the mandibular canal from the mandibular notch to 3 mm posterior of the root of the third molar. The dimensions, the surface area, and the volume of the bone grafts were measured and evaluated.

RESULTS

The average dimensions of the graft material obtained from the anterior part of ascending ramus were 37.60 x 33.17 x 22.48 x 9.15 mm; the average bone volume was 2.36 mL; and the average surface area of the graft material was 495.13 mm(2).

CONCLUSION

The results of the present study show that the anterior part of ascending ramus can be used as the donor site for reconstruction of small bone defects in the oral and maxillofacial region.

Evaluation of the mandible as an alternative autogenous bone source for oral and maxillofacial reconstruction

The objective of this study was to quantify the amount of bone graft material present in the different regions of the mandible while avoiding the inferior alveolar neurovascular bundle, mental foramen and tooth injury. The study was carried out on 16 samples of dry, cadaverous skull. The dimensions of the anterior part of ascending ramus, mandibular symphysis and mandibular body in these samples were evaluated. The osteotomy lines in the anterior part of the ascending ramus were made in front of the mandibular canal from the mandibular notch to 3 mm posterior of the root of the third molar. The osteotomy line in the mandibular body was made just medial to the external oblique ridge from the ascending ramus to approximately 3 mm posterior to the mental foramen. Vertical osteotomy lines were then made from the cut ends of the first osteotomy down to the lower border of the mandible. The osteotomy lines in the mandibular symphysis were performed on the mandible with 5-mm safety margins caudal to the expected position of the mandibular dentition, anterior to the position of the mental foramen, and cephalad to the inferior border of the mandible. It was determined that the dimensions of the anterior part of the ascending ramus were 37.60 mm x 33.17 mm x 22.48 mm x 9.15 mm, and the thickest part of the graft material was 12.23 mm. The average horizontal length of the mandibular body bone was 35.10 mm, and the average vertical length was 19.13 mm. The dimensions of the bone graft obtained from the mandibular symphysis were 45.36 mm x 10.31 mm, and the average thickness was 9.63 mm. Based on the results of this study, it is apparent that the different regions of the mandible can reliably be selected as the harvest site in a variety of oral and maxillofacial reconstructive procedures.