- Email: [email protected]
A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients
Journal Pre-proof A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients Ibrahim Mohamed Nowair, PhD, Associate Professor, Mohamed Kamal Eid, PhD, Lecturer, Dr Mohamed Kamal Eid PII:
S1010-5182(19)31153-9
DOI:
https://doi.org/10.1016/j.jcms.2019.12.013
Reference:
YJCMS 3411
To appear in:
Journal of Cranio-Maxillo-Facial Surgery
Received Date: 6 September 2019 Revised Date:
11 November 2019
Accepted Date: 15 December 2019
Please cite this article as: Nowair IM, Eid MK, Kamal Eid M, A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients, Journal of Cranio-Maxillofacial Surgery, https://doi.org/10.1016/j.jcms.2019.12.013. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients
1. Ibrahim Mohamed Nowair Degree: PhD (Oral and Maxillofacial Surgery) Affiliation: Associate Professor of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Egypt Email: [email protected] 2. Mohamed Kamal Eid Degree: PhD (Oral and Maxillofacial Surgery) Affiliation: Lecturer in Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Egypt Email: [email protected] Corresponding author Dr Mohamed Kamal Eid Oral & Maxillofacial Surgery Department, Faculty of Dentistry, Tanta University, Egypt Address: Omar Abdelazez St, Alzzaeafran District, Mansoura – Dakahlia 35511, Egypt Telephone: 002 0502204302 Mobile: 002 01220033033 Email: [email protected]
Introduction Ameloblastoma is a benign but locally invasive tumor, which generally occurs in the jawbone. It is formed of odontogenic epithelium, with fibrous, mature stroma devoid of odontogenic ectomesenchyme (Lau, 2006; Fregnani et al., 2010). Ameloblastomas can be classified clinically as unicystic, solid or multicystic, peripheral, and malignant. These clinical variants are distinguished according to their gross features. Unicystic ameloblastoma often presents as a local cyst-like lesion, while the multicystic or solidtype can grow to huge proportions and infiltrate surrounding tissues (Gortzak et al., 2006). Peripheral ameloblastoma often occurs in the alveolar mucosa. It is the soft-tissue variant, although it can also involve the underlying bone. The malignant ameloblastoma is a rare entity, which comprises ameloblastomas that have already metastasized, while maintaining its classical microscopic features (Corio et al., 1987). The treatment of choice for solid or multicystic ameloblastoma has been radical surgery with 1 cm safe margins and resection of adjacent soft tissue, with subsequent reconstruction (Ooi et al., 2014). Some authors have proposed combined conservative surgery and long-term follow-up as a possible alternative, especially in cases of good patient compliance and low risk of the involvement of adjacent structures (Hammarfjord et al., 2013). For peripheral ameloblastoma, local resection is recommended (Pogrel et al., 2009). The definitive treatment for ameloblastoma is surgery, however, the extent of surgical intervention and the adoption of conservative or radical approaches remain controversial. Conservative surgery refers to marsupialization or enucleation, with or without supplementary techniques (e.g. peripheral ostectomy and/or chemical cauterization),
whereas radical surgery refers to mandibulectomy or segmental resection of the lesion (Hammarfjord et al., 2013). Unicystic ameloblastoma is considered to be a distinct clinicopathological entity. This is largely due to its unilocular radiographic appearance, histological features, association with an unerupted tooth, occurrence in the mandibles of younger patients, and lower recurrence rate after conservative surgical treatment (Rosenstein T et al., 2001; Lee et al., 2004). Surgical resection of the mandible can lead to numerous complications even after reconstruction, such as jaw deformity, dysfunction, and psychological distress, especially for young patients (Lau, 2006; Pogrel et al., 2009; Ohiroa et al., 2019). Conservative treatment, including enucleation, curettage, and surgical excision with peripheral ostectomy, is associated with less serious functional and esthetic impairment; nevertheless, it can result in a higher rate of recurrence if inadequately performed (Rastogi et al., 2010; Almeida et al., 2016). The purpose of this study was to evaluate the dredging method as a modified surgical technique for the management of large unicystic ameloblastomas in young patients, through clinical, radiological, and histological analysis.
Patients and Methods This prospective study included 20 patients (n = 20) with a histological diagnosis of unicystic ameloblastoma. All the patients were clinically examined in the Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Tanta University. The chief complaint in all patients was a slowly growing, painless, mandibular swelling. Histopathological analysis was performed in the Oral Pathology Department, Faculty of Dentistry, Tanta University, based on the diagnostic criteria outlined by
the World Health Organization (WHO). The study was approved by the Research and Ethical Committee of the Faculty of Dentistry, Tanta University. The treatment plan was explained to the patients in simple terms and plain language, with an informed consent form outlining the steps and schedule of surgical management, as well as the follow-up intervals.
Preoperative evaluation Patient history included personal data (name, age, sex, and occupation), date of lesion discovery, mode of growth (rapid or slow), symptoms (e.g. pain and/or ipsilateral paresthesia of the lower lip), and history of previous surgical intervention, if any. Neurosensory function of inferior alveolar nerve (IAN) was evaluated by subjective evaluation and a two-point discrimination test. Clinical examination included the site and extent of mandibular bony expansion, the condition of related teeth (absent, displaced, or mobile), and covering soft tissues (normal, ulcerated from indentation of opposing teeth, or scarred due to previous incisional biopsy). Radiographical examination involved orthopantomography (OPG) and computerized tomography (CT) scans to assess the extent of uni/multilocular radiolucency, mono/bicortical expansion, and the condition of related teeth (displaced, impacted, or unerupted) (Figures 1– 4). Surgical procedure (Figures 5 and 6)
Our treatment protocol involved an initial deflation (marsupialization) step, which was followed by a later enucleation step and subsequent repeated dredging (Acharyaa et al., 2017; Ohiroa et al., 2019). The first marsupialization step involved surgical excision of a portion of the cystic wall, overlying bone, and mucoperiosteum in order to release intracystic pressure and allow the formation of a clear bony outline for the lesion. In the second step, enucleation of the lesion was performed after a clear bony outline had been already achieved. Impacted teeth involved in the lesion, if any, were also surgically removed. Complete removal of the tumor wall was supplemented by peripheral ostectomy involving bone burring; then the bony cavity was kept open. The procedure was followed by repeated dredging to remove any scar tissue that could fill the bony cavity and prevent bone formation. Dredging was carried out at 2–3-month intervals, with the general aim of boosting new bone formation at the expense of potential growth of any residual pathological tissue. Histopathological examination of all specimens was essential to ensure elimination of any residual tumor tissue and decrease recurrence rate. The follow-up periods started after the date of the second of two consecutive pathology-free scar tissue samples. Strict and regular follow-up was maintained throughout the treatment period.
Postoperative evaluation Patients underwent early clinical postoperative evaluation followed by weekly examination for 3 months after marsupialization. Postoperative evaluation was continued for 3 months after enucleation and for 6 months
after the final dredging procedure. Clinical evaluation aimed to assess wound healing, ipsilateral paresthesia of the lower lip, bone formation, and restoration of normal bone contour, as well as to spot any potential lesion recurrence. Regarding
radiography,
OPG
was
performed
3
months
after
marsupialization, 3 months after enucleation, and 6 months after the final dredging. Cone-beam computerized tomography (CBCT) was carried out 6 months after the final dredging to detect any recurrence and to assess bone density, height, and width before installation of dental implants.
Results A total of 20 patients, who presented with unilateral, unilocular, radiolucent, mandibular lesions were diagnosed as having unicystic ameloblastoma by clinical, radiographical, and aspiration testing, and by incisional biopsy for histopathological diagnosis. The study population comprised 16 males and four females, showing evident male predominance (a male:female ratio of 4:1). The age of patients at the time of diagnosis ranged from 13 to 24 years (mean age 18.5 years). The most common site was the ramus of the mandible followed by the body and angle of the mandible (Table 1). Postoperatively, all patients showed uneventful soft tissue healing around the open bony cavity. Two cases complained of temporary ipsilateral paresthesia of the lower lip due to manipulation of the inferior alveolar bundle during peripheral ostectomy by the round surgical bur. Such complaints gradually disappeared within 3 months after the final dredging with the use of oral neurotonics. Postoperative radiographical evaluation showed new bone formation, which filled the hollowed mandible with gradually increasing bone volume and density as compared with the immediate postoperative
radiographs. At the final follow-up stage, a normal mandibular bony contour had been achieved, with complete remodeling and without radiographical signs of recurrence (Figures 7–14).
Discussion The management of ameloblastoma in children and adolescents remains controversial, due to its effects on the growth of the craniofacial skeleton, dentition, and soft tissues. Unicystic ameloblastoma is thought to be less aggressive, with various treatment modalities being advocated. Radical or extensive surgery can result in deformity and dysfunction of the jaw, thereby affecting the physical and psychological development of the young patient. In consideration of the age of patients, and the site, nature, and extent of the lesion, we adopted the conservative dredging method for this study. The treatment protocol consisted of marsupialization to reduce the size of the lesion, followed by enucleation and dredging to prevent recurrence and accelerate new bone formation (Nakamura et al., 1995; Nakamura et al., 2002; Bansal et al., 2015). The conservative technique adopted in our department for the management of large unicystic ameloblastomas in young patients has the following advantages: it is performed under local anesthesia; it requires less hospitalization time because it is performed in the outpatient clinic; there is less donor site morbidity as compared with radical surgery by resection and subsequent reconstruction, and, finally, it induces less fear and apprehension in both patients and parents. Unicystic ameloblastoma is diagnosed in a relatively younger age group of patients. The clinical and radiographical features of unicystic ameloblastoma in our study were generally in line with other series in the literature. The occurrence of unicystic ameloblastoma in patients aged less than 17 years has been reported previously (Kahan,1989; Olaitan et
al., 1997; Rosenstein et al., 2001). The 20 cases in our study had an average age of 18.5 years, which was higher than that reported in the literature (14.5 years). The male-to-female ratio was 4:1, which was in accordance with that reported by Zhang et al. (Zhang et al., 2010). Most patients complained of a gradually increasing, painless swelling of the mandible, with bicortical bony expansion. The mandibular ramus region was the most represented site, which was in agreement with that reported by Takahashi et al. (Takahashi et al.,1998). Continuous and regular follow-up, aimed at detecting any recurrence as early as possible, is essential for the dredging method. Our postoperative follow-up regimen focused on the elimination of the lesion without recurrence and preserving the form and function of the mandible. Such a target would not be possible without the strict follow-up schedule and the cooperation of patients, as previously emphasized (Muller et al., 1985; Ohiro et al., 2019). A limitation of this dredging method as a modified approach for the surgical treatment of unicystic ameloblastoma was the lengthy surgical phase and the long follow-up period. Repeated dredging of scar tissue that filled up the bony cavity and meticulous histopathological analysis of all specimens were essential to ensure elimination of any residual pathology and prevention of recurrence.
Conclusion The dredging method, as a modified surgical technique, may represent a reliable approach for the management of unicystic ameloblastoma in young patients, with good functional and esthetic outcomes and a low risk for recurrence.
Conflict of interest statement
The authors declare no conflicts of interest. Funding The authors received no specific funding for this work. List of references Acharyaa P, Jaisani MR, Dongola A, Yadava RP, Bhattarai N, Mahat AK: Dredging — a conservative treatment for odontogenic tumor of jaws (case report). J Oral Maxillofac Surg Med Pathol 29(5):422–6, 2017. DOI: https://doi.org/10.1016/j.ajoms.2017.03.004 Almeida Rde A, Andrade ES, Barbalho JC, Vajgel A, Vasconcelos BC: Recurrence rate following treatment for primary multicystic ameloblastoma: systematic review and meta-analysis. Int J Oral Maxillofac Surg 45(3):359–67, 2016. DOI: 10.1016/j.ijom.2015.12.016 Bansal S, Desai R.S, Shirsat P, Prasad P, Karjodkar F, Andrade N: The occurrence and pattern of ameloblastoma in children and adolescents: an Indian institutional study of 41 years and review of the literature. Int J Oral Maxillofac Surg 44(6):725–731, 2015. DOI:10.1016/j.ijom.2015.01.002 Corio RL, Goldblatt LI, Edwards PA, Hartman KS: Ameloblastic carcinoma: a clinicopathologic study and assessment of eight cases. Oral Surg Oral Med Oral Pathol 64(5):570–6, 1987. DOI: 10.1016/00304220(87)90063-6 Fregnani ER, da Cruz Perez DE, de Almeida OP, Kowalski LP, Soares FA, de Abreu Alves F: Clinicopathological study and treatment outcomes of 121 cases of ameloblastomas. Int J Oral Maxillofac Surg 39(2):145–9, 2010. DOI: 10.1016/j.ijom.2009.11.022 Gortzak RA, Latief BS, Lekkas C, Slootweg PJ: Growth characteristics of large mandibular ameloblastomas: report of 5 cases with implications for the approach to surgery. Int J Oral Maxillofac Surg 35(8):691–5, 2006. DOI: 10.1016/j.ijom.2006.02.013 Hammarfjord O, Roslund J, Abrahamsson P, Nilsson P, Thor A, Magnusson M, et al.: Surgical treatment of recurring ameloblastoma, are there options? Br J Oral Maxillofac Surg 51(8):762–6, 2013. DOI: 10.1016/j.bjoms.2013.08.013 Kahan MA: Ameloblastoma in young persons: a clinicopathologic anaylsis and etiologic investigation. Oral Surg Oral Med Oral Pathol 67(6):706–15, 1989. DOI: 10.1016/0030-4220(89)90013-3
Lau SL, Samman N: Recurrence related to treatment modalities of unicystic ameloblastoma: a systematic review. Int J Oral Maxillofac Surg 35(8):681–90, 2006. DOI: 10.1016/j.ijom.2006.02.016 Lee PK, Samman N, Ng IO: Unicystic ameloblastoma — use of Carnoy’s solution after enucleation. Int J Oral Maxillofac Surg 33(3):263–7, 2004. DOI: 10.1006/ijom.2003.0496 Muller H, Shootweg PJ: The ameloblastoma, the controversial approach to therapy. J Maxillofac Surg 13(2):79–84, 1985. DOI: https://doi.org/10.1016/S0301-0503(85)80021-7 Nakamura N, Higuchi Y, Tashiro H, Ohishi M: Marsupialization of cystic ameloblastoma: a clinical and histopathologic study of the growth characteristics before and after marsupialization. J Oral Maxillofac Surg 53(7):748–54,1995. DOI: https://doi.org/10.1016/0278-2391(95)90323-2 Nakamura N, Higuchi Y, Mitsuyasu T, Sandra F, Ohishi M: Comparison of long-term results between different approaches to ameloblastoma. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 93(1):13–20, 2002. DOI: https://doi.org/10.1067/moe.2002.119517 Ohiroa Y, Yamadaa T, Kakuguchia W, Kobayashib I, Kitamurac T, Tei K: Modified ‘dredging method’ for complicated solid/multicystic ameloblastoma in the mandible: report of a case treated by fractionated enucleation. J Oral Maxillofac Surg Med Pathol 31(2):121–5, 2019. DOI: https://doi.org/10.1016/j.ajoms.2018.11.001 Olaitan AA, Adekeye EO: Unicystic ameloblastoma of the mandible: a long-term follow-up. J Oral Maxillofac Surg 55(4):345–8, 1997. https://doi.org/10.1016/S0278-2391(97)90122-1 Ooi A, Feng J, Tan HK, Ong YS: Primary treatment of mandibular ameloblastoma with segmental resection and free fibula reconstruction: achieving satisfactory outcomes with low implant–prosthetic rehabilitation. J Plast Reconstr Aesthet Surg 67(4):498–505, 2014. DOI: 10.1016/j.bjps.2014.01.005 Pogrel MA, Montes DM: Is there a role for enucleation in the management of ameloblastoma? Int J Oral Maxillofac Surg 38(8):807– 12, 2009. DOI: 10.1016/j.ijom.2009.02.018 Rastogi V, Pandilwar PK, Maitra S: Ameloblastoma: an evidence based study. J Maxillofac Oral Surg 9(2):173–7, 2010. DOI: 10.1007/s12663010-0060-5 Rosenstein T, Pogrel MA, Smith RA, Regezi JA: Cystic ameloblastoma — behavior and treatment of 21 cases. J Oral Maxillofac Surg 59(11):1311–6, 2001. DOI: 10.1053/joms.2001.27522 Takahashi K, Miyauchi K, Sato K: Treatment of ameloblastoma in children. Br J Oral Maxillofac Surg 36(6):453–6, 1998. DOI: https://doi.org/10.1016/S0266-4356(98)90462-4
Zhang J, Gu Z, Jiang L, Zhao J, Tian M, Zhou J, et al.: Ameloblastoma in children and adolescents. Br J Oral Maxillofac Surg 48(7):549–54, 2010. DOI: 10.1016/j.bjoms.2009.08.020
Captions to illustrations Figure 1: Preoperative OPG of case number 12, showing a well-defined unilocular radiolucent area on the right side of the ramus, angle, and body of the mandible, with an impacted 3rd molar involved within the unicystic lesion. Figure 2: Preoperative CT of case number 16, coronal view, showing unilocular radiolucency on the left side of the ramus, angle, and body of the mandible. Figure 3: Preoperative CT of case number 16, sagittal view, showing unilocular radiolucency on the left side of the ramus, angle, and body of the mandible, with root resorption of the associated 1st molar and impacted 2nd and 3rd molars. Figure 4: Preoperative CT of case number 16, three-dimensional view, showing a huge osteolytic lesion on the left side of the mandible. Figure 5: Intraoral clinical photograph of case number 16, showing the first dredging. Figure 6: Intraoral clinical photograph of case number 16, showing the final dredging. Figure 7: Postoperative OPG photoradiograph of case number 16, 3 months after marsupialization, in which a crestal approach was used after extraction of the 1st molar, with incisional biopsy from the pathological lining and removal of an impacted 2nd molar. Figure 8: Postoperative OPG photoradiograph of case number 16, 3 months after enucleation. Figure 9: Postoperative OPG photoradiograph of case number 16, 6 months after the final dredging, showing bone formation and a normal bone contour. Figure 10: Postoperative CBCT photoradiographs of case number 16, showing a normal bone contour with cortical outline, without evidence of recurrence 18 months after the final dredging. Figure 11: Postoperative CBCT photoradiographs of case number 16, showing virtual implant simulation with suitable-sized dental implants. Figure 12: Postoperative intraoral clinical photograph of case number 16, showing uneventful soft tissue healing after the final dredging. Figure 13: Postoperative intraoral clinical photograph of case number 16, showing insertion of two implants in the left mandibular body region. Figure 14: Postoperative OPG photoradiographs of case number 16, showing osseointegrated dental implants with prosthetic loading.
Table 1: Demographic data (age, sex distribution) and lesion sites for patients undergoing the dredging method for unicystic ameloblastoma (n = 20)
Age range
Gender Male
Site of lesion
Female
Total
Mandibular
Mandibular body
ramus
and angle
13–16
2
0
1
1
2
17–20
6
1
5
2
7
21–24
8
3
6
5
11
Total
16
4
12
8
20
S1010-5182(19)31153-9
DOI:
https://doi.org/10.1016/j.jcms.2019.12.013
Reference:
YJCMS 3411
To appear in:
Journal of Cranio-Maxillo-Facial Surgery
Received Date: 6 September 2019 Revised Date:
11 November 2019
Accepted Date: 15 December 2019
Please cite this article as: Nowair IM, Eid MK, Kamal Eid M, A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients, Journal of Cranio-Maxillofacial Surgery, https://doi.org/10.1016/j.jcms.2019.12.013. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients
1. Ibrahim Mohamed Nowair Degree: PhD (Oral and Maxillofacial Surgery) Affiliation: Associate Professor of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Egypt Email: [email protected] 2. Mohamed Kamal Eid Degree: PhD (Oral and Maxillofacial Surgery) Affiliation: Lecturer in Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Egypt Email: [email protected] Corresponding author Dr Mohamed Kamal Eid Oral & Maxillofacial Surgery Department, Faculty of Dentistry, Tanta University, Egypt Address: Omar Abdelazez St, Alzzaeafran District, Mansoura – Dakahlia 35511, Egypt Telephone: 002 0502204302 Mobile: 002 01220033033 Email: [email protected]
Introduction Ameloblastoma is a benign but locally invasive tumor, which generally occurs in the jawbone. It is formed of odontogenic epithelium, with fibrous, mature stroma devoid of odontogenic ectomesenchyme (Lau, 2006; Fregnani et al., 2010). Ameloblastomas can be classified clinically as unicystic, solid or multicystic, peripheral, and malignant. These clinical variants are distinguished according to their gross features. Unicystic ameloblastoma often presents as a local cyst-like lesion, while the multicystic or solidtype can grow to huge proportions and infiltrate surrounding tissues (Gortzak et al., 2006). Peripheral ameloblastoma often occurs in the alveolar mucosa. It is the soft-tissue variant, although it can also involve the underlying bone. The malignant ameloblastoma is a rare entity, which comprises ameloblastomas that have already metastasized, while maintaining its classical microscopic features (Corio et al., 1987). The treatment of choice for solid or multicystic ameloblastoma has been radical surgery with 1 cm safe margins and resection of adjacent soft tissue, with subsequent reconstruction (Ooi et al., 2014). Some authors have proposed combined conservative surgery and long-term follow-up as a possible alternative, especially in cases of good patient compliance and low risk of the involvement of adjacent structures (Hammarfjord et al., 2013). For peripheral ameloblastoma, local resection is recommended (Pogrel et al., 2009). The definitive treatment for ameloblastoma is surgery, however, the extent of surgical intervention and the adoption of conservative or radical approaches remain controversial. Conservative surgery refers to marsupialization or enucleation, with or without supplementary techniques (e.g. peripheral ostectomy and/or chemical cauterization),
whereas radical surgery refers to mandibulectomy or segmental resection of the lesion (Hammarfjord et al., 2013). Unicystic ameloblastoma is considered to be a distinct clinicopathological entity. This is largely due to its unilocular radiographic appearance, histological features, association with an unerupted tooth, occurrence in the mandibles of younger patients, and lower recurrence rate after conservative surgical treatment (Rosenstein T et al., 2001; Lee et al., 2004). Surgical resection of the mandible can lead to numerous complications even after reconstruction, such as jaw deformity, dysfunction, and psychological distress, especially for young patients (Lau, 2006; Pogrel et al., 2009; Ohiroa et al., 2019). Conservative treatment, including enucleation, curettage, and surgical excision with peripheral ostectomy, is associated with less serious functional and esthetic impairment; nevertheless, it can result in a higher rate of recurrence if inadequately performed (Rastogi et al., 2010; Almeida et al., 2016). The purpose of this study was to evaluate the dredging method as a modified surgical technique for the management of large unicystic ameloblastomas in young patients, through clinical, radiological, and histological analysis.
Patients and Methods This prospective study included 20 patients (n = 20) with a histological diagnosis of unicystic ameloblastoma. All the patients were clinically examined in the Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Tanta University. The chief complaint in all patients was a slowly growing, painless, mandibular swelling. Histopathological analysis was performed in the Oral Pathology Department, Faculty of Dentistry, Tanta University, based on the diagnostic criteria outlined by
the World Health Organization (WHO). The study was approved by the Research and Ethical Committee of the Faculty of Dentistry, Tanta University. The treatment plan was explained to the patients in simple terms and plain language, with an informed consent form outlining the steps and schedule of surgical management, as well as the follow-up intervals.
Preoperative evaluation Patient history included personal data (name, age, sex, and occupation), date of lesion discovery, mode of growth (rapid or slow), symptoms (e.g. pain and/or ipsilateral paresthesia of the lower lip), and history of previous surgical intervention, if any. Neurosensory function of inferior alveolar nerve (IAN) was evaluated by subjective evaluation and a two-point discrimination test. Clinical examination included the site and extent of mandibular bony expansion, the condition of related teeth (absent, displaced, or mobile), and covering soft tissues (normal, ulcerated from indentation of opposing teeth, or scarred due to previous incisional biopsy). Radiographical examination involved orthopantomography (OPG) and computerized tomography (CT) scans to assess the extent of uni/multilocular radiolucency, mono/bicortical expansion, and the condition of related teeth (displaced, impacted, or unerupted) (Figures 1– 4). Surgical procedure (Figures 5 and 6)
Our treatment protocol involved an initial deflation (marsupialization) step, which was followed by a later enucleation step and subsequent repeated dredging (Acharyaa et al., 2017; Ohiroa et al., 2019). The first marsupialization step involved surgical excision of a portion of the cystic wall, overlying bone, and mucoperiosteum in order to release intracystic pressure and allow the formation of a clear bony outline for the lesion. In the second step, enucleation of the lesion was performed after a clear bony outline had been already achieved. Impacted teeth involved in the lesion, if any, were also surgically removed. Complete removal of the tumor wall was supplemented by peripheral ostectomy involving bone burring; then the bony cavity was kept open. The procedure was followed by repeated dredging to remove any scar tissue that could fill the bony cavity and prevent bone formation. Dredging was carried out at 2–3-month intervals, with the general aim of boosting new bone formation at the expense of potential growth of any residual pathological tissue. Histopathological examination of all specimens was essential to ensure elimination of any residual tumor tissue and decrease recurrence rate. The follow-up periods started after the date of the second of two consecutive pathology-free scar tissue samples. Strict and regular follow-up was maintained throughout the treatment period.
Postoperative evaluation Patients underwent early clinical postoperative evaluation followed by weekly examination for 3 months after marsupialization. Postoperative evaluation was continued for 3 months after enucleation and for 6 months
after the final dredging procedure. Clinical evaluation aimed to assess wound healing, ipsilateral paresthesia of the lower lip, bone formation, and restoration of normal bone contour, as well as to spot any potential lesion recurrence. Regarding
radiography,
OPG
was
performed
3
months
after
marsupialization, 3 months after enucleation, and 6 months after the final dredging. Cone-beam computerized tomography (CBCT) was carried out 6 months after the final dredging to detect any recurrence and to assess bone density, height, and width before installation of dental implants.
Results A total of 20 patients, who presented with unilateral, unilocular, radiolucent, mandibular lesions were diagnosed as having unicystic ameloblastoma by clinical, radiographical, and aspiration testing, and by incisional biopsy for histopathological diagnosis. The study population comprised 16 males and four females, showing evident male predominance (a male:female ratio of 4:1). The age of patients at the time of diagnosis ranged from 13 to 24 years (mean age 18.5 years). The most common site was the ramus of the mandible followed by the body and angle of the mandible (Table 1). Postoperatively, all patients showed uneventful soft tissue healing around the open bony cavity. Two cases complained of temporary ipsilateral paresthesia of the lower lip due to manipulation of the inferior alveolar bundle during peripheral ostectomy by the round surgical bur. Such complaints gradually disappeared within 3 months after the final dredging with the use of oral neurotonics. Postoperative radiographical evaluation showed new bone formation, which filled the hollowed mandible with gradually increasing bone volume and density as compared with the immediate postoperative
radiographs. At the final follow-up stage, a normal mandibular bony contour had been achieved, with complete remodeling and without radiographical signs of recurrence (Figures 7–14).
Discussion The management of ameloblastoma in children and adolescents remains controversial, due to its effects on the growth of the craniofacial skeleton, dentition, and soft tissues. Unicystic ameloblastoma is thought to be less aggressive, with various treatment modalities being advocated. Radical or extensive surgery can result in deformity and dysfunction of the jaw, thereby affecting the physical and psychological development of the young patient. In consideration of the age of patients, and the site, nature, and extent of the lesion, we adopted the conservative dredging method for this study. The treatment protocol consisted of marsupialization to reduce the size of the lesion, followed by enucleation and dredging to prevent recurrence and accelerate new bone formation (Nakamura et al., 1995; Nakamura et al., 2002; Bansal et al., 2015). The conservative technique adopted in our department for the management of large unicystic ameloblastomas in young patients has the following advantages: it is performed under local anesthesia; it requires less hospitalization time because it is performed in the outpatient clinic; there is less donor site morbidity as compared with radical surgery by resection and subsequent reconstruction, and, finally, it induces less fear and apprehension in both patients and parents. Unicystic ameloblastoma is diagnosed in a relatively younger age group of patients. The clinical and radiographical features of unicystic ameloblastoma in our study were generally in line with other series in the literature. The occurrence of unicystic ameloblastoma in patients aged less than 17 years has been reported previously (Kahan,1989; Olaitan et
al., 1997; Rosenstein et al., 2001). The 20 cases in our study had an average age of 18.5 years, which was higher than that reported in the literature (14.5 years). The male-to-female ratio was 4:1, which was in accordance with that reported by Zhang et al. (Zhang et al., 2010). Most patients complained of a gradually increasing, painless swelling of the mandible, with bicortical bony expansion. The mandibular ramus region was the most represented site, which was in agreement with that reported by Takahashi et al. (Takahashi et al.,1998). Continuous and regular follow-up, aimed at detecting any recurrence as early as possible, is essential for the dredging method. Our postoperative follow-up regimen focused on the elimination of the lesion without recurrence and preserving the form and function of the mandible. Such a target would not be possible without the strict follow-up schedule and the cooperation of patients, as previously emphasized (Muller et al., 1985; Ohiro et al., 2019). A limitation of this dredging method as a modified approach for the surgical treatment of unicystic ameloblastoma was the lengthy surgical phase and the long follow-up period. Repeated dredging of scar tissue that filled up the bony cavity and meticulous histopathological analysis of all specimens were essential to ensure elimination of any residual pathology and prevention of recurrence.
Conclusion The dredging method, as a modified surgical technique, may represent a reliable approach for the management of unicystic ameloblastoma in young patients, with good functional and esthetic outcomes and a low risk for recurrence.
Conflict of interest statement
The authors declare no conflicts of interest. Funding The authors received no specific funding for this work. List of references Acharyaa P, Jaisani MR, Dongola A, Yadava RP, Bhattarai N, Mahat AK: Dredging — a conservative treatment for odontogenic tumor of jaws (case report). J Oral Maxillofac Surg Med Pathol 29(5):422–6, 2017. DOI: https://doi.org/10.1016/j.ajoms.2017.03.004 Almeida Rde A, Andrade ES, Barbalho JC, Vajgel A, Vasconcelos BC: Recurrence rate following treatment for primary multicystic ameloblastoma: systematic review and meta-analysis. Int J Oral Maxillofac Surg 45(3):359–67, 2016. DOI: 10.1016/j.ijom.2015.12.016 Bansal S, Desai R.S, Shirsat P, Prasad P, Karjodkar F, Andrade N: The occurrence and pattern of ameloblastoma in children and adolescents: an Indian institutional study of 41 years and review of the literature. Int J Oral Maxillofac Surg 44(6):725–731, 2015. DOI:10.1016/j.ijom.2015.01.002 Corio RL, Goldblatt LI, Edwards PA, Hartman KS: Ameloblastic carcinoma: a clinicopathologic study and assessment of eight cases. Oral Surg Oral Med Oral Pathol 64(5):570–6, 1987. DOI: 10.1016/00304220(87)90063-6 Fregnani ER, da Cruz Perez DE, de Almeida OP, Kowalski LP, Soares FA, de Abreu Alves F: Clinicopathological study and treatment outcomes of 121 cases of ameloblastomas. Int J Oral Maxillofac Surg 39(2):145–9, 2010. DOI: 10.1016/j.ijom.2009.11.022 Gortzak RA, Latief BS, Lekkas C, Slootweg PJ: Growth characteristics of large mandibular ameloblastomas: report of 5 cases with implications for the approach to surgery. Int J Oral Maxillofac Surg 35(8):691–5, 2006. DOI: 10.1016/j.ijom.2006.02.013 Hammarfjord O, Roslund J, Abrahamsson P, Nilsson P, Thor A, Magnusson M, et al.: Surgical treatment of recurring ameloblastoma, are there options? Br J Oral Maxillofac Surg 51(8):762–6, 2013. DOI: 10.1016/j.bjoms.2013.08.013 Kahan MA: Ameloblastoma in young persons: a clinicopathologic anaylsis and etiologic investigation. Oral Surg Oral Med Oral Pathol 67(6):706–15, 1989. DOI: 10.1016/0030-4220(89)90013-3
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Captions to illustrations Figure 1: Preoperative OPG of case number 12, showing a well-defined unilocular radiolucent area on the right side of the ramus, angle, and body of the mandible, with an impacted 3rd molar involved within the unicystic lesion. Figure 2: Preoperative CT of case number 16, coronal view, showing unilocular radiolucency on the left side of the ramus, angle, and body of the mandible. Figure 3: Preoperative CT of case number 16, sagittal view, showing unilocular radiolucency on the left side of the ramus, angle, and body of the mandible, with root resorption of the associated 1st molar and impacted 2nd and 3rd molars. Figure 4: Preoperative CT of case number 16, three-dimensional view, showing a huge osteolytic lesion on the left side of the mandible. Figure 5: Intraoral clinical photograph of case number 16, showing the first dredging. Figure 6: Intraoral clinical photograph of case number 16, showing the final dredging. Figure 7: Postoperative OPG photoradiograph of case number 16, 3 months after marsupialization, in which a crestal approach was used after extraction of the 1st molar, with incisional biopsy from the pathological lining and removal of an impacted 2nd molar. Figure 8: Postoperative OPG photoradiograph of case number 16, 3 months after enucleation. Figure 9: Postoperative OPG photoradiograph of case number 16, 6 months after the final dredging, showing bone formation and a normal bone contour. Figure 10: Postoperative CBCT photoradiographs of case number 16, showing a normal bone contour with cortical outline, without evidence of recurrence 18 months after the final dredging. Figure 11: Postoperative CBCT photoradiographs of case number 16, showing virtual implant simulation with suitable-sized dental implants. Figure 12: Postoperative intraoral clinical photograph of case number 16, showing uneventful soft tissue healing after the final dredging. Figure 13: Postoperative intraoral clinical photograph of case number 16, showing insertion of two implants in the left mandibular body region. Figure 14: Postoperative OPG photoradiographs of case number 16, showing osseointegrated dental implants with prosthetic loading.
Table 1: Demographic data (age, sex distribution) and lesion sites for patients undergoing the dredging method for unicystic ameloblastoma (n = 20)
Age range
Gender Male
Site of lesion
Female
Total
Mandibular
Mandibular body
ramus
and angle
13–16
2
0
1
1
2
17–20
6
1
5
2
7
21–24
8
3
6
5
11
Total
16
4
12
8
20