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CASE REPORT - TRAUMA
Year : 2019  |  Volume : 9  |  Issue : 1  |  Page : 218-220

Mandibular body fracture during inferior alveolar nerve transposition: Review of literature


1 Oral and Maxillofacial Diseases Research Center; Department of Oral and Maxillofacial Surgery, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
2 Dental Research Center; Department of Oral and Maxillofacial Pathology, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran

Date of Web Publication13-Jun-2019

Correspondence Address:
Dr. Saeedeh Khajehahmadi
Dental Research Center, Mashhad University of Medical Sciences, Vakilabad Blvd, Mashhad
Iran
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DOI: 10.4103/ams.ams_2_19

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  Abstract 


Inferior alveolar nerve transposition is a useful adjunctive surgery in implant dentistry when there is insufficient bone between the ridge crest and the inferior dental canal. However, if this surgery is done carelessly, complications such as mandibular fracture and permanent lower lip numbness can occur. This article reports the first case of bilateral mandibular body fracture occurring during inferior alveolar nerve transposition. The surgical management of a complicated bilateral displaced mandibular body fracture is explained herein. A literature review of mandibular fracture after inferior alveolar nerve transposition is also presented. Adhering to the principles of fracture, treatment is mandatory for the successful management of mandibular fracture after inferior alveolar nerve transposition.

Keywords: Dental implant, inferior alveolar nerve, mandibular fracture


How to cite this article:
Rahpeyma A, Khajehahmadi S. Mandibular body fracture during inferior alveolar nerve transposition: Review of literature. Ann Maxillofac Surg 2019;9:218-20

How to cite this URL:
Rahpeyma A, Khajehahmadi S. Mandibular body fracture during inferior alveolar nerve transposition: Review of literature. Ann Maxillofac Surg [serial online] 2019 [cited 2019 Jul 16];9:218-20. Available from: http://www.amsjournal.com/text.asp?2019/9/1/218/260332




  Introduction Top


Mandibular fracture after inferior alveolar nerve transposition is extremely rare. Most occurrences are presented in the literature as case reports. When such a rare complication occurs, the case should be managed according to previously reported cases and surgeon experience. The inferior alveolar nerve transposition is an advanced surgery in the field of implant dentistry that requires special training. It was first introduced in 1977 for pain relief of denture pressure on superficially located mental nerves.[1] After dental implants became popular, this technique was re-introduced to increase implant length in the posterior mandible with insufficient space between the ridge crest and the inferior dental canal.[2] Complications are often focused on the neurosensory alterations in the lower lip; however, mandibular fracture is reported as a rare but major complication of this surgery.[3],[4] This event is iatrogenic; however, the management should follow the principles of mandibular jaw fracture treatment.


  Case Report Top


The patient was a 51-year-old female who required mandibular posterior dental implants. A preoperative cone-beam computed tomography showed 7 mm of bone between the ridge crest and the inferior dental canal. The surgeon decided to do a bilateral inferior alveolar nerve transposition concomitant with dental implant insertion.

In this patient, bilateral jaw fracture occurred after nerve transposition and bicortical insertion of dental implants (two on each side). The surgeon put the patient in intermaxillary fixation (IMF) with IMF screws and used only wire osteosynthesis near the fracture edges on the left side. The right-side fracture was treated by closed reduction.

In the postoperative radiograph, a wire was pulled through the bone, and proximal segments were rotated bilaterally in the superior and medial direction.

The patient came back 6 months later with malocclusion and mandibular angle depression. Malunion on the left side and nonunion with rounding of bony edges on the right side were observed. There was also a limitation in mouth opening (30 mm/MIO).

One week before surgery, botulinum toxin (Botox)® was injected into the masseter and temporal muscles to reduce the muscle forces and eliminate the need for coronoidectomy.

The extraoral submandibular incision was used to access the fracture sites. The malunion segments on the left side were osteotomized, and after the teeth were placed into the appropriate occlusion, internal fixation with a reconstruction plate was done. On the right side, there was a 25-mm gap between the two segments. Dental implants inserted in the left mandibular body prevented drill penetration into the bone adjacent to the fracture for osteosynthesis. A 5-hole titanium miniplate and a 5-hole titanium reconstruction plate were used for internal fixation. Cancellous chips were used to fill the bony gap on the right side. This gap was maintained using an 8-hole titanium reconstruction plate [Figure 1]. The postoperative period was uneventful.
Figure 1: (a) Bilateral mandibular fracture after inferior alveolar nerve transposition, (b) open reduction and internal fixation with bone grafting

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  Discussion Top


Fracture of the mandible after inferior alveolar nerve relocation is mentioned as being rare; it is the most infrequent complication of inferior alveolar nerve transposition.[5] This event happens in jaws with narrow buccolingual dimensions and lingual position of the inferior alveolar nerve. The apicobasal distance of the mandibular canal from the mandibular inferior border is another important measurement. Using large diameter implants adjacent to each other and the engagement of the inferior alveolar nerve by the implants can also weaken the compression band of the mandible. This can also serve as a contributing factor.[6]

The buccal cortical plate reaches its maximum thickness in the second molar region. The dimensions of the buccal window play a vital role in this topic. The lowest limit of the bony window to the inferior mandibular border is recommended to be >7 mm,[7] and the window should measure 6 mm vertically.[8] The maximum amount of bone superior to the buccal bony window should be preserved for the anchorage of dental implants. If these requirements are not present, then bone grafting before inferior alveolar nerve transposition is recommended.[9]

The surgeon should avoid large diameter bicortical dental implants in jaws with small buccolingual and occluso-apical dimensions. Using the bridge design in the posterior mandible weakens bone less than using three adjacent fixtures. Conservative bone removal is recommended to bring out the inferior alveolar nerve from the mandible instead of large buccal bony window [Figure 2].[10]
Figure 2: Schematic pictures: (a) bicortical implants and large buccal bony window weakens the jaw; (b) slot technique with small buccal bony window not engaging inferior mandibular border

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If mandibular body fracture occurs during the inferior alveolar nerve transposition, the surgeon should adhere to the principles of jaw fracture treatment.[11] If the orientation of the fracture line prevents displacement of the fragments, holding the teeth in appropriate occlusion for 4 weeks is sufficient.[12] The majority of fractures are delayed and occur in the 1st month after surgery with a radiolucent rim around the dental implants. The need to remove the loose implants causes the fracture to resemble comminuted fractures with bone loss. In such cases, the segments are not stable, and thus, internal fixation with a reconstruction plate is mandatory.

When a complication occurs that is beyond the expectations of the patient; the surgeon tries to manage it in the simplest possible way. However, in jaw fractures, the surgeon should adhere strictly to the principles of treatment to prevent further complications.

A search of the PubMed database for English-language articles on inferior alveolar nerve transposition/lateralization and mandibular fracture revealed only nine previous cases [Table 1].[10],[12],[13],[14],[15],[16],[17] All of them were unilateral events in partially edentulous patients, and all fractures except the case presented in this article had occurred late and not as an intraoperative complication. The term “late” is defined arbitrarily when describing surgical complications. In this study, a fracture occurring after patient discharge from the operating room, but before completion of prosthodontic fibrication and fixation was considered to be late. If a fracture occurs after the osseointegration of the dental implants, it is not considered to be a complication of the inferior alveolar nerve transposition.[18]
Table 1: Demographic information of nine reported cases of mandibular fracture after inferior alveolar nerve transposition

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The current case is the first bilateral fracture of the mandible after inferior alveolar nerve repositioning. Soft/liquid diet and IMF as a conservative treatment are recommended in incomplete mandibular fractures. Titanium meshes or reconstruction plates are devices used for internal fixation in displaced fractures. Free bone grafting may be needed if the mandible has severe atrophy.


  Conclusion Top


When a surgeon performs an advanced dental implant procedure, complicated conditions are unavoidable. Adhering to the principles of fracture, the treatment is mandatory for the successful management of mandibular fracture after inferior alveolar nerve transposition.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Alling CC. Lateral repositioning of inferior alveolar neurovascular bundle. J Oral Surg 1977;35:419.  Back to cited text no. 1
    
2.
Jensen O, Nock D. Inferior alveolar nerve repositioning in conjunction with placement of osseointegrated implants: A case report. Oral Surg Oral Med Oral Pathol 1987;63:263-8.  Back to cited text no. 2
    
3.
Khajehahmadi S, Rahpeyma A, Bidar M, Jafarzadeh H. Vitality of intact teeth anterior to the mental foramen after inferior alveolar nerve repositioning: Nerve transpositioning versus nerve lateralization. Int J Oral Maxillofac Surg 2013;42:1073-8.  Back to cited text no. 3
    
4.
Turhani D, Ohlmeier KH, Sutter W, Kielbassa AM. Undesirable course of an oral implant rehabilitation in a patient with a long history of bulimia nervosa: Case report and review of the literature. Quintessence Int 2019;50:68-79.  Back to cited text no. 4
    
5.
Boffano P, Roccia F, Gallesio C, Berrone S. Pathological mandibular fractures: A review of the literature of the last two decades. Dent Traumatol 2013;29:185-96.  Back to cited text no. 5
    
6.
Oh WS, Roumanas ED, Beumer J 3rd. Mandibular fracture in conjunction with bicortical penetration, using wide-diameter endosseous dental implants. J Prosthodont 2010;19:625-9.  Back to cited text no. 6
    
7.
Al-Siweedi SY, Nambiar P, Shanmuhasuntharam P, Ngeow WC. Gaining surgical access for repositioning the inferior alveolar neurovascular bundle. ScientificWorldJournal 2014;2014:719243.  Back to cited text no. 7
    
8.
Jensen J, Reiche-Fischel O, Sindet-Pedersen S. Nerve transposition and implant placement in the atrophic posterior mandibular alveolar ridge. J Oral Maxillofac Surg 1994;52:662-8.  Back to cited text no. 8
    
9.
Proussaefs P. Vertical alveolar ridge augmentation prior to inferior alveolar nerve repositioning: A patient report. Int J Oral Maxillofac Implants 2005;20:296-301.  Back to cited text no. 9
    
10.
Kan JY, Lozada JL, Boyne PJ, Goodacre CJ, Rungcharassaeng K. Mandibular fracture after endosseous implant placement in conjunction with inferior alveolar nerve transposition: A patient treatment report. Int J Oral Maxillofac Implants 1997;12:655-9.  Back to cited text no. 10
    
11.
Soehardi A, Meijer GJ, Manders R, Stoelnga PJ. An inventory of mandibular fractures associated with implants in atrophic edentulous mandibles: A survey of dutch oral and maxillofacial surgeons. Int J Oral Maxillofac Implants 2011;26:1087-93.  Back to cited text no. 11
    
12.
Luna AH, Passeri LA, de Moraes M, Moreira RW. Endosseous implant placement in conjunction with inferior alveolar nerve transposition: A report of an unusual complication and surgical management. Int J Oral Maxillofac Implants 2008;23:133-6.  Back to cited text no. 12
    
13.
dos Santos PL, Gaujac C, Shinohara EH, Filho OM, Garcia-Junior IR. Incomplete mandibular fracture after lateralization of the inferior alveolar nerve for implant placement. J Craniofac Surg 2013;24:e222-4.  Back to cited text no. 13
    
14.
Losa PM, Cebrian JL, Guiñales J, Burgueño M, Chamorro M. Mandibular fracture after inferior alveolar nerve lateralization: A rare and misunderstood complication. J Craniofac Surg 2015;26:e682-3.  Back to cited text no. 14
    
15.
Karlis V, Bae RD, Glickman RS. Mandibular fracture as a complication of inferior alveolar nerve transposition and placement of endosseous implants: A case report. Implant Dent 2003;12:211-6.  Back to cited text no. 15
    
16.
Khojasteh A, Hassani A, Motamedian SR, Saadat S, Alikhasi M. Cortical bone augmentation versus nerve lateralization for treatment of atrophic posterior mandible: A retrospective study and review of literature. Clin Implant Dent Relat Res 2016;18:342-59.  Back to cited text no. 16
    
17.
Sharifi R, Beshkar M, Mobayeni MR, Hasheminasab M. Inferior alveolar nerve medialization for dental implant placement: Case report with the introduction of a new technique. Int J Oral Maxillofac Implants 2018;33:e113-e115.  Back to cited text no. 17
    
18.
da Costa Ribeiro R, Barbosa Luna AH, Sverzut CE, Sverzut AT. Failure of osseointegrated dental implant after alveolar nerve transposition: A report of an unusual complication and surgical management. Implant Dent 2017;26:645-8.  Back to cited text no. 18
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1]



 

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