TECHNICAL STRATEGY
Bone Flap Technique for Impacted Teeth Extraction and Bone Cysts Removal Gianmarco Saponaro, MD, Sandro Pelo, MD, Paolo De Angelis, DDS, Mario Forcione, MD,y Giuseppe D’Amato, DDS, and Alessandro Moro, MD Abstract: The treatment of cystic lesions and the extraction of impacted third molars are 2 of the most common procedures in oral and maxillofacial surgery. The surgical treatment of cysts of the jaws can consist of a cystectomy, a cystotomy, or a staged combination of the 2 procedures. The surgical techniques developed for the extraction of impacted third molars are: coronectomy, orthodontic extraction, and surgery using intraoral or extraoral methods. There are various complications related to both surgical treatments. With regards to these complications, authors’ department has developed a new surgical technique based on a previously described technique, which provides better support to the mucoperiosteal flap and improves bone regeneration after healing. Additionally, authors’ goal was to reduce the risk of nerve injury, which has been achieved thanks to a direct visualization of the inferior alveolar nerve as well as cystic lesion or the dental element. The surgical procedure described produces major advantages over the traditional alternatives, despite needing a longer operation. This technique is particularly useful in the treatment of cystic lesions that have caused considerable bone loss. It can also be utilized for cysts or impacted dental elements strictly linked to the inferior alveolar nerve. Key Words: Bone cyst, bone flap, cystectomy, dental extraction, impacted molar, impacted teeth, inferior alveolar nerve (J Craniofac Surg 2016;27: 1084–1086)
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he treatment of cystic lesions and the extraction of impacted third molars are 2 of the most common procedures in oral and maxillofacial surgery. Cystic lesions of the jaws can be treated with conservative nonsurgical management or surgical management. Conservative nonsurgical procedures should be used for all inflammatory periapical lesions whose size and extent are not of critical importance.1 The surgical treatment of cysts of the jaws can consist of a cystectomy, a cystotomy, or a staged combination of the 2 procedures. The surgical techniques developed for the extraction From the Department of Oral and Maxillo-facial Surgery, Catholic University of the Sacred Hearth Medical School, Rome, Italy; and yDepartment of Neurosurgery, Queen Elizabeth Hospital, Birmingham, UK. Received October 16, 2015; final revision received December 29, 2015. Accepted for publication January 31, 2016. Address correspondence and reprint requests to Gianmarco Saponaro, MD, Department of Oral and Maxillo-Facial Surgery, ‘‘A. Gemelli’’ Teaching Hospital, Catholic University of the Sacred Hearth Medical School, Via G Moscati 31, 00168 Rome, Italy; E-mail:
[email protected] The authors report no conflicts of interest. Copyright # 2016 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000002606
of impacted third molars are: coronectomy which was introduced by Pogrel et al2; orthodontic extraction and surgery using intraoral or extraoral methods. There are various complications related to both surgical treatments. A pathologic fracture of the mandible after a cystectomy is rare 3,4 but it may occur in those patients who have lost a large amount of bone due to cysts. A mandibular fracture after the removal of an impacted lower third molar is a major complication but it is also rare.5 A wound breakdown is a frequent complication, especially when the defect is extensive and it can increase the risk of infection. Another relevant complication is an inferior alveolar nerve injury that can cause temporary or permanent anesthesia, dysesthesia, or a paresthesia along the region innervated by the inferior alveolar nerve. Furthermore, the extraction of an impacted third molar can result in damage to the osteoperiodontal complex of the second molar. In addition, the characteristics of the bone defect may influence bone regeneration after healing. With regards to these complications, our department has developed a new surgical technique based on the technique recently described by Chen et al,6 which provides better support to the mucoperiosteal flap and improves bone regeneration after healing. Additionally, our goal was to reduce the risk of nerve injury, which has been achieved thanks to a direct visualization of the inferior alveolar nerve as well as cystic lesion or the dental element.
DESCRIPTION OF THE TECHNIQUE The incision is performed through the mucosa and a mucoperiosteal flap is elevated. The area of the cyst or of the retained tooth is marked and a squared bone flap is designed and prepared with a rotating burr (Fig. 1). The bone flap is elevated and the cyst, or the retained element, is removed through the opening with a direct visualization of the inferior alveolar nerve. The bone flap is then repositioned and secured through four holes on the edges of the flap with a 2/0 resorbable suture (Fig. 2). The mucoperiosteal flap is then repositioned and sutured.
METHODS In total, 20 patients were treated with this technique by our department between January 1, 2014 and January 1, 2015. Their ages ranged between 21 and 50 years with an average age of 30. Nine of the patients (5 females and 4 males) were suffering from impacted dental elements in close proximity to the inferior alveolar nerve and 11 patients (6 females and 5 males) had a cystic bone lesion that displaced the nerve, the smallest lesion being 1.5 cm in diameter and the largest, 4 cm. All patients underwent radiological examinations prior to surgery. A panorex and a computed tomography Dentascan were performed to document the position and the involvement of the inferior alveolar nerve. All patients underwent the surgical procedure using the aforementioned technique.
1084 The Journal of Craniofacial Surgery Volume 27, Number 4, June 2016 Copyright © 2016 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
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Bone Flap Technique for Jaw Cysts
There were no patients of postsurgical atrophy or mal-union of the bone flap.
DISCUSSION
FIGURE 1. Clockwise direction—design of the flap on the mandibular bone containing an odontogenic cyst; bone flap elevation; visualization of the inferior alveolar nerve.
Clinical follow-ups were performed at 1 week, 3 months, and 6 months after surgery. A radiological follow-up was performed 3 months after the operation with panorex. Further follow-ups ranged between 6 and 18 months, with the average follow-up time being 14 months. The sensitivity of the areas innerved by the inferior alveolar nerve was evaluated at every clinical examination with the 2-point discrimination test. The presence of bone atrophy was evaluated on x-ray.
RESULTS There were no patients of intraoperative damage of the inferior alveolar nerve. All patients were administered intravenous corticosteroid therapy in the first 2 days after the operation. Eighteen of the 20 patients reported an alteration in sensitivity in the inferior alveolar nerve immediately after the operation. Spontaneous recovery was documented in 15 patients in the first week and in the first month for 3 patients. No permanent nerve injury was documented in this series. No patient of infection was reported.
FIGURE 2. Schematic picture of the bone flap with hole drilled at its edge for retain with suture.
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Cystotomy is a simple procedure, it involves opening the cyst to form a surgical window in the wall of the cyst, removing the contents of the cyst, and maintaining a connection between the cyst and the oral cavity. The only part of the cyst that is eliminated is the one within the surgical window, the rest of the cystic lining is left in situ. Cystotomy can be used on its own or it can be used as the first phase in management, delaying enucleation. The main advantages of a cystotomy are the preservation of vital structures and the possibility to promote the eruption of an unerupted teeth. For this reasons it can be indicated in children in which the cyst is preventing dental elements to erupt and also for the prevention of oronasaloroantral fistula or pathologic fractures. Moreover, it is the surgical procedure that incurs the least stress in debilitated patients. The main problem with Cystotomy is that the pathologic tissue remains in situ without a histological examination, which increases the possibility of recurrences of the lesion. Furthermore, the patient has significant postoperative discomfort and needs considerable care to avoid the risk of infection. All these problems can continue for a few months, depending on the size of the cystic cavity and the rate of bone fill. Given these disadvantages, most of cysts are now treated with cystectomy and not with cystotomy. Cystectomy procedures involve the opening the cystic walls, the removal of the cystic lining and conclude with the primary closure of the cavity. This procedure has certain advantages over Cystotomy. First is the primary closure of the wound; second the wound heals faster; third it results in less postoperative discomfort and reduces the need for postoperative care, and fourth it allows for examination of the entire cystic lining. A cystectomy can be performed only when it is possible to remove the cystic lining entirely and if the defect can be covered with soft tissue. This procedure is chosen for the treatment of small cysts with a diameter of up to 2 cm. Extensive defects will give rise to large clots and are prone to secondary infections with subsequent wound breakdown.7 Thanks to the creation of a bone window and the repositioning of the bone flap, our technique prevents the wound from collapsing or dehiscing, as it provides support to the mucoperiosteal flap. After a cystectomy, bone regeneration in the central area of the defect may be incomplete during the healing process.3,8– 10 Better bone regeneration was observed in young patients and in monocortical defects compared in bicortical defects.9,10 In contrast to cystectomy, the creation of a bone flap prevents soft tissue growth into the bone cavity. This procedure uses the principle of guided bone regeneration and the bone flap acts like a space-making and space maintenance barrier which increases bone regeneration. In this way, it is possible to avoid the risk of surgical atrophy. Mandibular cysts can affect the inferior alveolar nerve and a cystectomy can damage it. Cysts may displace or encompass the inferior alveolar nerve. The elevation of the bone flap allows us a direct visualization of the neurovascular bundle and the surgeon can complete a microdissection and expose its course through the cyst. When the neurovascular bundle has been properly protected, the cyst can be removed.11 The third molar roots can be in close contact with the inferior alveolar nerve. After the extraction of mandibular third molars, damage to the inferior alveolar nerve has been reported in up to 8.4% of patients.12 For this reason, new techniques have been developed as alternatives to traditional extraction methods. Among these new techniques is coronectomy. Coronectomy, or deliberate vital tooth retention, removes the crown of a tooth and
1085 Copyright © 2016 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited. 2016 Mutaz B. Habal, MD
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leaves the root in situ reducing the possibility of nerve damage.2 On the other hand, this procedure has some limitations. The failure rate of coronectomy ranged from 2.3% to 38.3%, and reoperation rates ranged from 0 to 4.9%.13 The most common complication reported for this technique was tooth migration from the mandibular canal and subsequent root exposure.14,15 Our technique avoids these complications and allows a view of the root, the inferior alveolar nerve, and their connections. Orthodontic extraction is another technique that has been introduced to decrease the risk of nerve injury. This procedure consists of an orthodontic phase followed by a surgical one. The length of the orthodontic phase is the main problem of this procedure.12 Furthermore, if the inferior alveolar nerve is trapped between the roots of the tooth this technique cannot be used.
4. 5. 6. 7. 8. 9. 10.
CONCLUSIONS In summary, the surgical procedure described allows major advantages over the traditional alternatives, despite needing a longer operation. This technique is particularly useful in the treatment of cystic lesions which have caused considerable bone loss. It can also be utilized for cysts or impacted dental elements strictly linked to the inferior alveolar nerve, where this technique has proved extremely useful if the wound has to be sutured without bone support.
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REFERENCES
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1. Fernandes M, de Ataide I. Nonsurgical management of periapical lesions. J Conserv Dent 2010;13:240–245 2. Pogrel MA, Lee JS, Muff DF. Coronectomy: a technique to protect the inferior alveolar nerve. J Oral Maxillofac Surg 2004;62:1447–1452 3. Chiapasco M, Rossi A, Motta JJ, et al. Spontaneous bone regeneration after enucleation of large mandibular cysts: a radiographic computed
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analysis of 27 consecutive cases. J Oral Maxillofac Surg 2000;58: 942–948 Kreusch T, Wittig J, Friedrich M, et al. Therapy of jaw cysts: procedures and results [in German]. German Dental Journal 2010:65 Krimmel M, Reinert S. Mandibular fracture after third molar removal. J Oral Maxillofac Surg 2000;58:1110–1112 Chen K-W, Chang W-C, Wu C-T, et al. New technique for prevention of the wound dehiscence after jaw bone surgery a case report. Taiwan J Oral Maxillofac Surg 2015;26:84–92 Pedlar J, Frame JW. Oral and Maxillofacial Surgery. Philadelphia, PA: Elsevier’s Health Sciences, Churchill Livingstone; 2007 Ettl T, Gosau M, Sader R, et al. Jaw cysts—filling or no filling after enucleation? A review. J Craniomaxillofac Surg 2012;40:485–493 Ihan Hren N, Miljavec M. Spontaneous bone healing of the large bone defects in the mandible. Int J Oral Maxillofac Surg 2008;37:1111–1116 Kim TS, Lee JH. Spontaneous bone regeneration after enucleation of jaw cysts: a comparative study of panoramic radiography and computed tomography. J Korean Assoc Oral Maxillofac Surg 2010;36:100–107 Gasparini G, Boniello R, Saponaro G, et al. Long term follow-up in inferior alveolar nerve transposition: our experience. Biomed Res Int 2014;2014:170602 Kalantar Motamedi MR, Heidarpour M, Siadat S, et al. Orthodontic extraction of high-risk impacted mandibular third molars in close proximity to the mandibular canal: a systematic review. J Oral Maxillofac Surg 2015;73:1672–1685 Long H, Zhou Y, Liao L, et al. Coronectomy vs. total removal for third molar extraction: a systematic review. J Dent Res 2012;91:659–665 Agbaje JO, Heijsters G, Salem AS, et al. Coronectomy of deeply impacted lower third molar: incidence of outcomes and complications after one year follow-up. J Oral Maxillofac Res 2015;6:e1 Monaco G, De Santis G, Pulpito G, et al. what are the types and frequencies of complications associated with mandibular third molar coronectomy? A follow-up study. J Oral Maxillofac Surg 2015;73:1246–1253
# 2016 Mutaz B. Habal, MD 1086 Copyright © 2016 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
