Applications of coronoid process as a bone graft in maxillofacial surgery

Examination of coronoid foramen and coronoid canal with CBCT

Objective

This study aimed to examine the coronoid foramen using CBCT not only according to its localization, distribution to gender and age but also to determine whether there are canals associated with the coronoid foramen and to identify them and their clinical significance.

Methods

488 images obtained between 2022 and 2023 were retrospectively evaluated in sagittal, horizontal, and coronal sections. During the evaluation of the images, the number and localization of the coronoid foramen and the coronoid canals originating from this foramen were recorded and examined. In addition, the patient images were divided into different age groups and the presence of coronoid foramen was analyzed.

Results

Coronoid foramen was detected in 5.1 % and coronoid canal in 1.6 % of the images. Unilateral coronoid foramen was found in 1.4 % and bilateral coronoid foramen was found in 3.7 % of the patients. Unilateral coronoid canal was found in 1.0 % and bilateral coronoid canal in 0.6 % of the patients. When the presence of coronoid foramen was analyzed according to age groups, no significant difference was found between age groups.

Conclusion

Recognition of the coronoid foramen and coronoid canal will not only reduce the likelihood of complications in surgical procedures but also influence the treatment plan. Further research is needed to recognize the content of this variations.

The Regrowth of Mandibular Coronoid Process After Coronoidectomy: A Retrospective Analysis of 57 Cases

PURPOSE

Coronoidectomy is carried out frequently as a part of the cranial-maxillofacial surgery procedure. There are few articles on the fate of coronoid process after coronoidectomy, except that several case reports mentioned that coronoid process had regenerated. This study aimed to radiographically access the anatomic outcomes of coronoid process and investigate which factors were associated with the outcomes after coronoidectomy.

MATERIALS AND METHODS

A retrospective cohort study included patients undergoing coronoidectomy over a 7-year period. The primary outcome variable was the new coronoid process occurrence (yes/no). Secondary outcome variable was the type of the new coronoid process by evaluating its size, shape and position. Radiograph at 1-year postoperative visit was used to determine the outcomes. The predictor variables included age, sex, surgical purpose, surgical side, surgical approach and the maximal interincisal opening. Appropriate statistics were analyzed by SPSS version 22. χ² test and binary logistic regression were used to assess the association between predictor factors and anatomic outcomes (P <.05).

RESULTS

The study sample included 57 patients. In total, 96 coronoidectomies were performed. Seventy-four coronoid processes (77.1%) showed complete (n = 44, 45.8%), nonunion (n = 19, 19.8%) or partial (n = 11, 11.5%) regrowth, whereas no evidence of regeneration in 22 sites was observed radiographically at 1-year postoperative visit. Binary logistic regression showed that a young age (odds ratio 0.704; 95% confidence interval 0.562-0.882; P = .002) was significantly associated with regeneration of coronoid process.

CONCLUSIONS

Coronoid process can mostly regenerate after coronoidectomy. A young age may contribute to regrowth of coronoid process.

Preclinical and Clinical Applications of Biomaterials in the Enhancement of Wound Healing in Oral Surgery: An Overview of the Available Reviews

Oral surgery has undergone dramatic developments in recent years due to the use of biomaterials. The aim of the present review is to provide a general overview of the current biomaterials used in oral surgery and to comprehensively outline their impact on post-operative wound healing. A search in Medline was performed, including hand searching. Combinations of searching terms and several criteria were applied for study identification, selection, and inclusion. The literature was searched for reviews published up to July 2020. Reviews evaluating the clinical and histological effects of biomaterials on post-operative wound healing in oral surgical procedures were included. Review selection was performed by two independent reviewers. Disagreements were resolved by a third reviewer, and 41 reviews were included in the final selection. The selected papers covered a wide range of biomaterials such as stem cells, bone grafts, and growth factors. Bioengineering and biomaterials development represent one of the most promising perspectives for the future of oral surgery. In particular, stem cells and growth factors are polarizing the focus of this ever-evolving field, continuously improving standard surgical techniques, and granting access to new approaches.

[Long-term effects of autogenous coronoid grafts on the facial growth of children with unilateral temporomandibular joint ankylosis and reconstructed mandibular condyle]

OBJECTIVE

Mandibular condyle injury usually results in malocclusion and disharmony of facial growth in growing children. This study aimed to evaluate the long-term effects of autogenous coronoid grafts on the facial growth of children with unilateral temporomandibular joint (TMJ) ankylosis who underwent mandibular condyle reconstruction.

METHODS

Ten growing patients with unilateral bony TMJ ankylosis admitted in West China Hospital of Stomatology, Sichuan University between January 1st, 2008 and December 31st, 2016 were followed up and evaluated. These patients include three males and seven females with ages ranging from 5 years to 12 years at the time of surgery. Each patient underwent gap arthroplasty, condyle reconstruction with ipsilateral coronoid, and interposition of the pedicled temporalis fascial flap in a single operation. The postoperative follow-up ranged from 3 years to 8 years with an average of 4.9 years. Postoperative panoramic radiographs determined the growth of the mandibular height and length on the affected side and compared it with those of the healthy side.

RESULTS

All patients recovered uneventfully after surgery. At the end of follow-up period, the maximal mouth opening ranged from 32 mm to 41 mm with an average of 35.6 mm. Mandibular height and length continued to grow after the successful treatment of ankylosis using autogenous coronoid grafts for condyle reconstruction. However, growth deficit still existed. The final ramus height and mandibular length of the affected side at the end of follow-up increased by 25.3% (P<0.05) and 26.1% (P<0.05), respectively, compared with the initial values measured immediately after surgery. Growth rates of ramus height and mandibular length of the affected side were 47.1% and 27.2% lower (P<0.05) than those of the healthy side, respectively.

CONCLUSIONS

Mandibular height and length continued to grow after the successful treatment of ankylosis by using autogenous coronoid grafts for condyle reconstruction. However, growth deficit still existed. The growth rate of the affected mandible was reduced compared with that of the undisturbed side even after treatment of ankylosis.

Bone grafting materials in dentoalveolar reconstruction: A comprehensive review

Bone deficits of the jaws are often attributed to accidents, surgical removal of benign lesions or malignant neoplasms, congenital abnormalities, periodontal inflammation, tooth abscess or extraction and finally jaw atrophy due to advanced age or general disease. These bone defects require rehabilitation for a variety of reasons, e.g. maintaining the normal anatomic outline, eliminating empty space, aesthetic restoration and placing dental implants. Today, several techniques have been developed to eliminate these bone deformities including bone grafting, guided bone regeneration, distraction osteogenesis, use of growth factors and stem cells. Bone grafts consist of materials of natural or synthetic origin, implanted into the bone defect site, documented to possess bone healing properties. Currently, a variety of bone restorative materials with different characteristics are available, possesing different properties. Despite years of effort the 'perfect' bone reconstruction material has not yet been developed, a further effort is required to make this objective feasible. The aim of this article is to provide a contemporary and comprehensive overview of the grafting materials that can be applied in dentoalveolar reconstruction, discussing their properties, advantages and disadvantages, enlightening the present and the future perspectives in the field of bone regeneration.

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.

[Transoral coronoidectomy: Technical note]

INTRODUCTION

Among the skeletal causes of limited mouth opening, uni- or bilateral coronoid process hypertrophy, or Langenbeck disease, is the most frequent. It can be associated with an osteochondroma or a coronoid-malar bone conflict and is then called Jacob disease, an unilateral pathology. Treatment rests on coronoidectomy in both cases. This technique is illustrated via two cases, one Langenbeck and one Jacob disease.

TECHNICAL NOTE

A transoral approach was performed. After subperiosteal dissection, the coronoid process was cleared. The process was than severed at its base by means of a burr, freed from its temporal muscular fibers and removed. Mouth opening improved peroperatively. The surgical procedure was completed by active long-term physiotherapy beginning immediately after surgery.

DISCUSSION

Transoral coronoidectomy is a simple, quick and safe procedure. Extra-oral approaches present a high risk of facial nerve injury. In our first case, mouth opening improved from 24 to 36 mm after bilateral coronoidectomy and to 40 mm after physiotherapy. In our second case, mouth opening improved from 22 to 38 mm after unilateral coronoidectomy and to 43 mm after one year physiotherapy. Long-term post-operative physiotherapy is mandatory to get and maintain good results.