ARTICLE IN PRESS
YBJOM-4153; No. of Pages 5
Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach Ongkila Bhutia a,∗ , Lalit Kumar a , Anson Jose a , Ajoy Roychoudhury a , Anjan Trikha b a b
Department of Oral & Maxillofacial Surgery, All India Institute of Medical Sciences, New Delhi 110029, India Department of Anaesthesia, All India Institute of Medical Sciences, New Delhi 110029, India
Accepted 1 December 2013
Abstract The objective of this study was to evaluate any damage to the facial nerve after a retromandibular transparotid approach for open reduction and internal fixation (ORIF) of a subcondylar fracture. We studied 38 patients with 44 subcondylar fractures (3 bilateral and 38 unilateral) treated by ORIF through a retromandibular transparotid approach. All patients were followed up for 6 months. Postoperative function of the facial nerve was evaluated within 24 h of operation, and at 1, 3, and 12 weeks, and 6 months. Variables including type of fracture, degree of mouth opening, postoperative occlusion, lateral excursion of the mandible, and aesthetic outcome were also monitored. Nine of the 44 fractures resulted in transient facial nerve palsy (20%). Branches of the facial nerve that were involved were the buccal (n = 7), marginal mandibular (n = 2), and zygomatic (n = 1). In the group with lateral displacement, 2/15 showed signs of weakness, whereas when the fracture was medially displaced or dislocated 7/23 showed signs of weakness. Of the 9 sites affected, 7 had resolved within 3 months, and the remaining 2 resolved within 6 months. The mean (range) time to recovery of function was 12 weeks (3–6 months). There was no case of permanent nerve palsy. The retromandibular transparotid approach to ORIF does not permanently damage the branches of the facial nerve. Temporary palsy, though common, resolves in 3–6 months. Postoperative occlusion, mouth opening, and lateral excursion of the mandible were within the reference ranges. We had no infections, or fractured plates, or hypertrophic or keloid scars. © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Retromandibular transparotid approach; Condylar fracture; Facial nerve; Morbidity
Introduction It has been reported that condylar fractures account for 25–50% of all mandibular fractures.1,2 However, despite the high incidence, their management is controversial. The main conflict hinges on a choice between conservative and surgical management.3,4 Those who prefer closed treatment question the need for surgical management, because of the risks of infection, haemorrhage, an unsightly scar, and (most importantly) the possibility of injury to the branches of the facial nerve. Supporters of open reduction claim that only it can
∗
Corresponding author. Tel.: +91 9313349564. E-mail address: dr [email protected] (O. Bhutia).
give satisfactory results, and that it prevents long term effects such as shortening of the ramus, facial asymmetry, arthrosis of the temporomandibular joint, and impaired eating and speaking.2,5 The risk of facial nerve palsy is one of the main arguments against surgical management.6,7 Several approaches to the mandibular condyle have been described, which include preauricular, submandibular, intraoral, rytidectomy, and retromandibular.8,9 The retromandibular approach was first described by Hinds and Girroti in 196710 and modified by Koberg and Momma in 1978.11 It has an advantage over the other methods in that it involves minimal working distance from the incision to the fracture site and less morbidity to the facial nerve, which can be identified and retracted under direct vision. Other advantages include excellent exposure,
0266-4356/$ – see front matter © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bjoms.2013.12.002
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
YBJOM-4153; No. of Pages 5
2
ARTICLE IN PRESS O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
and aesthetically pleasing results because of the less conspicuous scar as it does not involve any supplemental incision and reduction is easy.12,13 Our aim was to document the damage to the facial nerve when the retromandibular transparotid approach was used for the treatment of subcondylar fractures.
Patients and methods This prospective clinical study included 38 patients with 44 fracture sites in the subcondylar region. Institutional ethics clearance was obtained before the study started. Only adult patients with fractures of the condylar neck and subcondyle with discrepancies in occlusion, those in whom pretraumatic occlusion could not be achieved by closed reduction, and those who were not willing to have intermaxillary fixation, were included. The function of the facial nerve preoperatively was within the reference ranges in all cases. Surgical technique Patients were operated on by a senior surgeon. Access to the fracture site was obtained through a retromandibular transparotid approach with an incision 0.5 cm below the ear lobe posterior to the posterior border of the ramus of the mandible, which extended inferiorly 3–3.5 cm up to the angle of the mandible. After the skin and subcutaneous incision had been incised a thin layer of platysma muscle was incised so that the parotid capsule was visible. We used blunt dissection parallel to the branches of the facial nerve, taking extra precautions to avoid injury to any of them. The posterior border of the ramus was then identified and the pterygomassetric sling incised. The site of the fracture was exposed subperiosteally to expose the bone so that a suitable retractor could be used to expose the site as high as possible. The reduction of a laterally-displaced fracture was easy. Light elastics were placed in the arch bars and a broad instrument placed between the occlusal surfaces was used to distract the mandible slightly caudally, while we simultaneously manipulated the condylar fragment into the fossa and reduced it. Medially-displaced fractures required an assistant to push down the ipsilateral molar region to give enough space to raise the medially-displaced fracture and to convert it into a laterally-displaced.fracture. When the fragments were small and could not be moved, a 2 mm screw was inserted and the head of the screw was held by a heavy artery forceps to facilitate the fragment in 3dimensional reduction. Before the plate was fixed, we did a maxillomandibular fixation. The fracture was fixed with titanium miniplates and screws using either 2 plates of a 2.0 mm non-locking adaptive system, or a single locking 2.0 mm plate. Once the fracture site had been fixed, the intermaxillary fixation was released and occlusion was checked. The wound was closed in layers, extra care being taken while suturing the parotid capsule to avoid a parotid fistula.
Fig. 1. Three-dimensional computed tomographic scan showing displacement of the subcondylar fracture.
Follow up Postoperative follow up radiograph or computed tomographic (CT) scan were taken to confirm reduction (Figs. 1 and 2). Standard assessment of motor response of facial nerve branches was made postoperatively as soon as the patient started to obey commands for voluntary facial muscle movements (within 24 h) (Table 1) and 1, 3, and 12 weeks, and 6 months postoperatively by one of the consultants. Ease of access to the fracture site, occlusion, lateral excursion of the mandible, mouth opening, parotid fistulation, duration of operation, infection of plates, and aesthetic outcome of wound were also monitored.
Results We evaluated 44 subcondylar fractures treated by ORIF using the retromandibular transparotid approach in all cases. No patient was lost to follow up at 6 months. The age range was 18–56 years. The aetiology of the fractures was mainly road
Fig. 2. Postoperative computed tomographic scan after fixation of the subcondylar fracture.
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
ARTICLE IN PRESS
YBJOM-4153; No. of Pages 5
O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx Table 1 Tests used to assess the function of the facial nerve.
1 2 3 4
Movement that patients were asked to make
Muscle
Nerve
Frown and wrinkle forehead Close eyes tightly Puff up cheeks and pucker lips Move lower lip downwards and laterally and evert vermilion border
Frontalis
Temporal branch
Orbicularis oculi Buccinator, orbicularis oris Depressor anguli oris, depressor labii inferioris, mentalis
Zygomatic branch Buccal Marginal mandibular
traffic crashes (n = 26, 68%) followed by fall (n = 6, 16%) and assault (n = 6, 16%). Fifteen sites had displaced condylar fragments with lateral overlap, in 23 there was dislocation with medial overlap, and 6 were not displaced. There was transient facial nerve palsy in the immediate postoperative period (24 h) in 9 sites (20%). In the group with lateral displacement (n = 15) some weakness was apparent in 2, whereas when the fracture was medially displaced or dislocated (n = 23) there were signs of weakness in 7. Seven sites completely recovered within 3 months and the remaining 2 within 6 months. The buccal nerve was involved most often (n = 7) followed by the marginal mandibular nerve (Table 2). All the sites that took 6 months to recover involved the buccal nerve. We also evaluated ease of access through exposure of fracture site, and 39/44 sites (89%) were straightforward and the operation took only about 30 min. The medially overlapped and dislocated fractures were difficult to locate and took more than 30 min. The retromandibular transparotid approach provided adequate access for reduction of the fracture. Clinical and radiographic evaluation showed good reduction in 38/44 sites (86%), but in the remaining 6 there was some discrepancy. The sites with medial overlap required a great deal of retraction and the operating time was prolonged. Immediate palsy of one or more branches of the facial nerve was more likely to develop in sites in which there were signs of dislocation and medial overlap. The postoperative occlusion, mouth opening, and lateral excursion of the mandible were within the reference ranges in all cases. No patient developed infection or fractured the plate, and there were no hypertrophic scars or keloid. Three parotid fistulas responded to local measures in 2–3 weeks postoperatively.
Discussion The incidence of transient damage to branches of the facial nerve has been reported to be between 12% and 48% (Table 2) when the retromandibular transparotid approach is used.5,7,8,13–16 Our incidence was 9/44 (20%). Such a high incidence may be attributed to the fact that access is between the branches
3
of the parotid gland and retraction can lead to transient neuropraxia resulting in palsy. The sites that required extra retraction because of medial overlap and dislocated condylar fragments developed more transient nerve palsies than the ones with lateral overlap. When the fracture was laterally displaced or dislocated, only 2/15 showed signs of weakness, whereas when the fracture was medially displaced or dislocated 7/23 showed signs of weakness. Neither in the studies reported elsewhere nor in our series was there any permanent damage (Table 3). A preauricular incision can be used to avoid retraction and is not in the vicinity of branches of the facial nerve. The low subcondylar fractures would be difficult to reduce through an incision too high for such fractures, and it may be good only for high condylar fractures. The incidence of facial nerve damage has been reported to be 3–48%17 with the preauricular approach. A submandibular approach can also be used for condylar fractures, but this has the disadvantage that it is a large incision with limited access to the condylar fragment, and this might compromise the quality of the reduction and fixation. The submandibular approach has also been reported to have an incidence of damage to the facial nerve of 5–48%.18 Though injuries to the facial nerve using an intraoral route have not to our knowledge been reported, comparisons with other extraoral approaches cannot be drawn because there is limited accessibility to the fracture site and a trochar and cannula are used for fixation. A review of reports that compared outcomes of traditional ORIF and endoscope-assisted ORIF of fractures of the mandibular condyle by Haug and Brandt19 showed a similar incidence of damage to the facial nerve, and it also has a steep learning curve and requires expensive equipment. Wilson et al.20 described the transmasseteric anteroparotid technique, which claims to reduce the occurrence of salivary fistulation and damage to the facial nerve. The transparotid approach, however, requires blunt dissection of the parotid capsule and parenchyma of the parotid, which increases the incidence of parotid fistulas and temporary damage to the facial nerve. Obese patients with fat cheeks also pose problems. Trost et al.21,22 showed that the damage to the facial nerve can be minimised if a high cervical transmasseteric anteroparotid approach is used. The retromandibular transparotid approach gives direct access to the fractured area and is the only incision that is close to the fracture line. The facial nerve divides into the temporofacial branch (consisting of the temporal and zygomatic branches) and the cervicofacial branch (the buccal, marginal mandibular, and cervical branches). The window between the buccal and marginal mandibular branches is the area of dissection. The superior margin of incision is required to be retracted more for plating or for locating the medial overlapping condyle. This may the reason for the increased incidence of neuropraxia in the buccal branch that was not found in the studies of Ellis and Dean8 and Manisali et al.13 Similar high incidences of buccal nerve palsy were also reported by Vesnaver et al.5 and Hyde et al.14 It is possible to reduce
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
ARTICLE IN PRESS
YBJOM-4153; No. of Pages 5
4
O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
Table 2 Reported incidences and sites of damage to the facial nerve. First author and reference no.
Year
No. of patients
No. of sites
No. (%) with transient facial nerve palsy
Branches affected
Ellis8 Ellis7
1993 2000
Not stated 83
29 83
14 (48) 16 (19)
Hyde14 Manisali13
2002 2003
25 20
25 20
3 6
Vesnaver5
2005
34
36
8 (22)
Downie15
2009
50
51
7 (14)
Yang16
2012
42
48
8 (18)
38
44
9 (20)
Marginal mandibular Marginal mandibular, buccal, n = 5, periorbital, n = 2 Buccal Marginal mandibular, n = 6, buccal, n = 1 Buccal, or zygomatic, or both Buccal, n = 4, zygomatic, n = 3 Buccal, or zygomatic, or both Buccal, n = 7, marginal mandibular, n = 2, zygomatic, n = 1
Present study
the incidence of buccal nerve palsy by dissecting the nerve and protecting it from retraction with a suitable instrument. We made no attempt to visualise the nerve during dissection, but if we encountered it we retracted it away from the site. To minimise the amount of retraction needed, particularly in medially-displaced condylar fragments, a vertical subsigmoid osteotomy could be made so that the medial condyle could be located and fixated extracorporeally as shown by Ellis and Dean.8 The cut bone would be devoid of periosteal and muscular attachments and would act as a non-vascularised bone graft plated to the ramus. Zygomatic nerve palsy was seen in one patient with a medially dislocated condyle, and we encountered extreme difficulty during reduction of the fractured segments as they required more retraction of soft tissue over a longer period,
which resulted in retraction paralysis of this branch. The facial nerve palsies that took longest to recover were associated with medially displaced condylar fractures, where longer operating time and more retraction of soft tissues were required to locate and retrieve the fragments, and this probably resulted in traction neuropraxia of the facial nerve. In neuropraxia functional recovery takes place within 0–12 weeks. However, during the postoperative period as oedema increases the inflow of nutrients to the nerve decreases. This results in axonal death (axonotmesis) and retrograde degeneration. However, the endoneurium in this type of injury is intact and axons will regrow through the channels, and this results in late recovery of function (3–6 months).23 A similar recovery pattern was seen in the present series. The transient palsy was probably the result of excessive retraction
Table 3 Reported duration of recovery after damage to the facial nerve. First author and reference no.
Year
Branches affected
Duration of recovery
Time until full recovery
Ellis8
1993
Marginal mandibular
All within 16 weeks
Ellis7
2000
6 weeks, transient palsy of all branches
Hyde14 Manisali13
2002 2003
Vesnaver5
2005
Marginal mandibular, buccal, n = 5, periorbital, n = 2 Buccal Marginal mandibular, n = 6, buccal, n = 1 Buccal, or zygomatic, or both
No case of total paralysis All within 6 months
Downie15
2009
–
Yang16
2012
Buccal, n = 4, zygomatic, n = 3 Buccal, or zygomatic, or both Buccal, n = 7, marginal mandibular, n = 2, zygomatic, n = 1
Present study
– 2 within 1 month
1 month All within 3 months
6 within 4–8 weeks
All within 2–4 weeks
1 mild weakness of upper lip and lower eyelid at 13 months All within 5–15 months 1 month
7 within 3 months
All within 6 months
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
YBJOM-4153; No. of Pages 5
ARTICLE IN PRESS O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
rather than neurotomesis. The mean duration of recovery was 12 weeks (Table 3). The parotid fistulas were managed by local dressings, having been the result of inadequate closure of the parotid capsule as also reported by Vesnaver et al.5 Water tight closure of the parotid capsule is recommended. The retromandibular transparotid approach is useful for treating undisplaced and laterally displaced subcondylar fractures, and it has the advantages of direct access to the fracture site, an inconspicuous scar, no permanent damage to the facial nerve, and easy open reduction and internal fixation. There may be a high incidence of transient nerve palsy but permanent damage has not been reported to our knowledge. When this approach is used for ORIF of subcondylar fractures care should be taken to be gentle when retracting soft tissues. There is a role for preoperative and postoperative counselling of patients who opt for this approach about temporary facial nerve palsy.
Sources of support in the form of grants No sources of support in the form of grants.
Competing interests None declared.
Ethical approval Approved by Institutional Ethical Committee.
References 1. Rowe NL, Killey HC, editors. Fractures of the facial skeleton. 2nd ed. Edinburgh: Churchill Livingstone; 1968. p. 80–92. 2. Silvennoinen U, Iizuka T, Lindquist C, et al. Different patterns of condylar fractures: an analysis of 382 patients in a 3-year period. J Oral Maxillofac Surg 1992;50:1032–7. 3. Takenoshita Y, Ishibashi H, Oka M. Comparison of functional recovery after nonsurgical and surgical treatment of condylar fractures. J Oral Maxillofac Surg 1990;48:1191–5. 4. Konstantinovic VS, Dimitrijevic B. Surgical versus conservative treatment of unilateral condylar process fractures: clinical and radiographic evaluation of 80 patients. J Oral Maxillofac Surg 1992;50:349–52.
5
5. Vesnaver A, Gorjanc M, Eberlinc A, et al. The preauricular transparotid approach for open reduction and internal fixation of condylar fractures. J Craniomaxillofac Surg 2005;33:169–79. 6. Chossegros C, Cheynet F, Blanc L, et al. Short retromandibular approach of subcondylar fractures – clinical and radiologic long term evaluation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82:248–52. 7. Ellis III E, McFadden D, Simon P, et al. Surgical complications with open treatment of mandibular condylar process fractures. J Oral Maxillofac Surg 2000;58:950–8. 8. Ellis III E, Dean J. Rigid fixation of mandibular condylar fractures. Oral Surg Oral Med Oral Pathol 1993;76:6–15. 9. Ellis III E, Zide MF. Transfacial approaches to the mandible. In: Ellis III E, Zide MF, Manson PN, editors. Surgical approaches to facial skeleton. Baltimore: Lippincott Willams & Wilkins; 1995. p. 123–85. 10. Hinds E, Girotti W. Vertical subcondylar osteotomy: a reappraisal. J Oral Surg 1967;24:164–70. 11. Koberg WR, Momma W. Treatment of fractures of the mandibular process by functional stable osteosynthesis using miniaturized dynamic compression plates. Int J Oral Surg 1978;7:256–62. 12. Zide MF, Kent JN. Indication for open reduction of mandibular condyle fractures. J Oral Maxillofac Surg 1983;41:89–98. 13. Manisali M, Amin M, Aghabeigi B, et al. Retromandibular approach to the mandibular condyle: a clinical and cadaveric study. Int J Oral Maxillofac Surg 2003;32:253–6. 14. Hyde N, Manisali M, Aghabeigi B, et al. The role of open reduction and internal fixation in unilateral fractures of the mandibular condyles: a prospective study. Br J Oral Maxillofac Surg 2002;40:19–22. 15. Downie JJ, Devlin MF, Carton AT, et al. Prospective study of morbidity associated with open reduction and internal fixation of the fractured condyle by the transparotid approach. Br J Oral Maxillofac Surg 2009;47:370–3. 16. Yang L, Patil PM. The retromandibular transparotid approach to mandibular subcondylar fractures. Int J Oral Maxillofac Surg 2012;41:494–9. 17. Hammer B, Schier P, Prein J. Osteosynthesis of condylar neck fractures: a review of 30 patients. Br J Oral Maxillofac Surg 1997;35:288–91. 18. Widmark G, Bagenholm T, Kahnberg KE, et al. Open reduction of subcondylar fractures. A study of functional rehabilitation. Int J Oral Maxillofac Surg 1996;25:107–11. 19. Haug RH, Brandt MT. Traditional versus endoscope-assisted open reduction with rigid internal fixation (ORIF) of adult mandibular condyle fractures: a review of the literature regarding current thoughts on management. J Oral Maxillofac Surg 2004;62:1272–9. 20. Wilson AW, Ethunandan M, Brennan PA. Transmasseteric antero-parotid approach for open reduction and internal fixation of condylar fractures. Br J Oral Maxillofac Surg 2005;43:57–60. 21. Trost O, Abu El-Naaj I, Trouilloud P, et al. High cervical transmasseteric anteroparotid approach for open reduction and internal fixation of condylar fracture. J Oral Maxillofac Surg 2008;66:201–4. Erratum: J Oral Maxillofac Surg 2008;66:607. 22. Trost O, Trouilloud P, Malka G. Open reduction and internal fixation of low subcondylar fractures of mandible through high cervical transmasseteric anteroparotid approach. J Oral Maxillofac Surg 2009;67:2446–51. 23. Selesnick SH, Patwardhan A. Acute facial paralysis: evaluation and early management. Am J Otolaryngol 1994;15:387–408.
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
YBJOM-4153; No. of Pages 5
Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach Ongkila Bhutia a,∗ , Lalit Kumar a , Anson Jose a , Ajoy Roychoudhury a , Anjan Trikha b a b
Department of Oral & Maxillofacial Surgery, All India Institute of Medical Sciences, New Delhi 110029, India Department of Anaesthesia, All India Institute of Medical Sciences, New Delhi 110029, India
Accepted 1 December 2013
Abstract The objective of this study was to evaluate any damage to the facial nerve after a retromandibular transparotid approach for open reduction and internal fixation (ORIF) of a subcondylar fracture. We studied 38 patients with 44 subcondylar fractures (3 bilateral and 38 unilateral) treated by ORIF through a retromandibular transparotid approach. All patients were followed up for 6 months. Postoperative function of the facial nerve was evaluated within 24 h of operation, and at 1, 3, and 12 weeks, and 6 months. Variables including type of fracture, degree of mouth opening, postoperative occlusion, lateral excursion of the mandible, and aesthetic outcome were also monitored. Nine of the 44 fractures resulted in transient facial nerve palsy (20%). Branches of the facial nerve that were involved were the buccal (n = 7), marginal mandibular (n = 2), and zygomatic (n = 1). In the group with lateral displacement, 2/15 showed signs of weakness, whereas when the fracture was medially displaced or dislocated 7/23 showed signs of weakness. Of the 9 sites affected, 7 had resolved within 3 months, and the remaining 2 resolved within 6 months. The mean (range) time to recovery of function was 12 weeks (3–6 months). There was no case of permanent nerve palsy. The retromandibular transparotid approach to ORIF does not permanently damage the branches of the facial nerve. Temporary palsy, though common, resolves in 3–6 months. Postoperative occlusion, mouth opening, and lateral excursion of the mandible were within the reference ranges. We had no infections, or fractured plates, or hypertrophic or keloid scars. © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Retromandibular transparotid approach; Condylar fracture; Facial nerve; Morbidity
Introduction It has been reported that condylar fractures account for 25–50% of all mandibular fractures.1,2 However, despite the high incidence, their management is controversial. The main conflict hinges on a choice between conservative and surgical management.3,4 Those who prefer closed treatment question the need for surgical management, because of the risks of infection, haemorrhage, an unsightly scar, and (most importantly) the possibility of injury to the branches of the facial nerve. Supporters of open reduction claim that only it can
∗
Corresponding author. Tel.: +91 9313349564. E-mail address: dr [email protected] (O. Bhutia).
give satisfactory results, and that it prevents long term effects such as shortening of the ramus, facial asymmetry, arthrosis of the temporomandibular joint, and impaired eating and speaking.2,5 The risk of facial nerve palsy is one of the main arguments against surgical management.6,7 Several approaches to the mandibular condyle have been described, which include preauricular, submandibular, intraoral, rytidectomy, and retromandibular.8,9 The retromandibular approach was first described by Hinds and Girroti in 196710 and modified by Koberg and Momma in 1978.11 It has an advantage over the other methods in that it involves minimal working distance from the incision to the fracture site and less morbidity to the facial nerve, which can be identified and retracted under direct vision. Other advantages include excellent exposure,
0266-4356/$ – see front matter © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bjoms.2013.12.002
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
YBJOM-4153; No. of Pages 5
2
ARTICLE IN PRESS O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
and aesthetically pleasing results because of the less conspicuous scar as it does not involve any supplemental incision and reduction is easy.12,13 Our aim was to document the damage to the facial nerve when the retromandibular transparotid approach was used for the treatment of subcondylar fractures.
Patients and methods This prospective clinical study included 38 patients with 44 fracture sites in the subcondylar region. Institutional ethics clearance was obtained before the study started. Only adult patients with fractures of the condylar neck and subcondyle with discrepancies in occlusion, those in whom pretraumatic occlusion could not be achieved by closed reduction, and those who were not willing to have intermaxillary fixation, were included. The function of the facial nerve preoperatively was within the reference ranges in all cases. Surgical technique Patients were operated on by a senior surgeon. Access to the fracture site was obtained through a retromandibular transparotid approach with an incision 0.5 cm below the ear lobe posterior to the posterior border of the ramus of the mandible, which extended inferiorly 3–3.5 cm up to the angle of the mandible. After the skin and subcutaneous incision had been incised a thin layer of platysma muscle was incised so that the parotid capsule was visible. We used blunt dissection parallel to the branches of the facial nerve, taking extra precautions to avoid injury to any of them. The posterior border of the ramus was then identified and the pterygomassetric sling incised. The site of the fracture was exposed subperiosteally to expose the bone so that a suitable retractor could be used to expose the site as high as possible. The reduction of a laterally-displaced fracture was easy. Light elastics were placed in the arch bars and a broad instrument placed between the occlusal surfaces was used to distract the mandible slightly caudally, while we simultaneously manipulated the condylar fragment into the fossa and reduced it. Medially-displaced fractures required an assistant to push down the ipsilateral molar region to give enough space to raise the medially-displaced fracture and to convert it into a laterally-displaced.fracture. When the fragments were small and could not be moved, a 2 mm screw was inserted and the head of the screw was held by a heavy artery forceps to facilitate the fragment in 3dimensional reduction. Before the plate was fixed, we did a maxillomandibular fixation. The fracture was fixed with titanium miniplates and screws using either 2 plates of a 2.0 mm non-locking adaptive system, or a single locking 2.0 mm plate. Once the fracture site had been fixed, the intermaxillary fixation was released and occlusion was checked. The wound was closed in layers, extra care being taken while suturing the parotid capsule to avoid a parotid fistula.
Fig. 1. Three-dimensional computed tomographic scan showing displacement of the subcondylar fracture.
Follow up Postoperative follow up radiograph or computed tomographic (CT) scan were taken to confirm reduction (Figs. 1 and 2). Standard assessment of motor response of facial nerve branches was made postoperatively as soon as the patient started to obey commands for voluntary facial muscle movements (within 24 h) (Table 1) and 1, 3, and 12 weeks, and 6 months postoperatively by one of the consultants. Ease of access to the fracture site, occlusion, lateral excursion of the mandible, mouth opening, parotid fistulation, duration of operation, infection of plates, and aesthetic outcome of wound were also monitored.
Results We evaluated 44 subcondylar fractures treated by ORIF using the retromandibular transparotid approach in all cases. No patient was lost to follow up at 6 months. The age range was 18–56 years. The aetiology of the fractures was mainly road
Fig. 2. Postoperative computed tomographic scan after fixation of the subcondylar fracture.
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
ARTICLE IN PRESS
YBJOM-4153; No. of Pages 5
O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx Table 1 Tests used to assess the function of the facial nerve.
1 2 3 4
Movement that patients were asked to make
Muscle
Nerve
Frown and wrinkle forehead Close eyes tightly Puff up cheeks and pucker lips Move lower lip downwards and laterally and evert vermilion border
Frontalis
Temporal branch
Orbicularis oculi Buccinator, orbicularis oris Depressor anguli oris, depressor labii inferioris, mentalis
Zygomatic branch Buccal Marginal mandibular
traffic crashes (n = 26, 68%) followed by fall (n = 6, 16%) and assault (n = 6, 16%). Fifteen sites had displaced condylar fragments with lateral overlap, in 23 there was dislocation with medial overlap, and 6 were not displaced. There was transient facial nerve palsy in the immediate postoperative period (24 h) in 9 sites (20%). In the group with lateral displacement (n = 15) some weakness was apparent in 2, whereas when the fracture was medially displaced or dislocated (n = 23) there were signs of weakness in 7. Seven sites completely recovered within 3 months and the remaining 2 within 6 months. The buccal nerve was involved most often (n = 7) followed by the marginal mandibular nerve (Table 2). All the sites that took 6 months to recover involved the buccal nerve. We also evaluated ease of access through exposure of fracture site, and 39/44 sites (89%) were straightforward and the operation took only about 30 min. The medially overlapped and dislocated fractures were difficult to locate and took more than 30 min. The retromandibular transparotid approach provided adequate access for reduction of the fracture. Clinical and radiographic evaluation showed good reduction in 38/44 sites (86%), but in the remaining 6 there was some discrepancy. The sites with medial overlap required a great deal of retraction and the operating time was prolonged. Immediate palsy of one or more branches of the facial nerve was more likely to develop in sites in which there were signs of dislocation and medial overlap. The postoperative occlusion, mouth opening, and lateral excursion of the mandible were within the reference ranges in all cases. No patient developed infection or fractured the plate, and there were no hypertrophic scars or keloid. Three parotid fistulas responded to local measures in 2–3 weeks postoperatively.
Discussion The incidence of transient damage to branches of the facial nerve has been reported to be between 12% and 48% (Table 2) when the retromandibular transparotid approach is used.5,7,8,13–16 Our incidence was 9/44 (20%). Such a high incidence may be attributed to the fact that access is between the branches
3
of the parotid gland and retraction can lead to transient neuropraxia resulting in palsy. The sites that required extra retraction because of medial overlap and dislocated condylar fragments developed more transient nerve palsies than the ones with lateral overlap. When the fracture was laterally displaced or dislocated, only 2/15 showed signs of weakness, whereas when the fracture was medially displaced or dislocated 7/23 showed signs of weakness. Neither in the studies reported elsewhere nor in our series was there any permanent damage (Table 3). A preauricular incision can be used to avoid retraction and is not in the vicinity of branches of the facial nerve. The low subcondylar fractures would be difficult to reduce through an incision too high for such fractures, and it may be good only for high condylar fractures. The incidence of facial nerve damage has been reported to be 3–48%17 with the preauricular approach. A submandibular approach can also be used for condylar fractures, but this has the disadvantage that it is a large incision with limited access to the condylar fragment, and this might compromise the quality of the reduction and fixation. The submandibular approach has also been reported to have an incidence of damage to the facial nerve of 5–48%.18 Though injuries to the facial nerve using an intraoral route have not to our knowledge been reported, comparisons with other extraoral approaches cannot be drawn because there is limited accessibility to the fracture site and a trochar and cannula are used for fixation. A review of reports that compared outcomes of traditional ORIF and endoscope-assisted ORIF of fractures of the mandibular condyle by Haug and Brandt19 showed a similar incidence of damage to the facial nerve, and it also has a steep learning curve and requires expensive equipment. Wilson et al.20 described the transmasseteric anteroparotid technique, which claims to reduce the occurrence of salivary fistulation and damage to the facial nerve. The transparotid approach, however, requires blunt dissection of the parotid capsule and parenchyma of the parotid, which increases the incidence of parotid fistulas and temporary damage to the facial nerve. Obese patients with fat cheeks also pose problems. Trost et al.21,22 showed that the damage to the facial nerve can be minimised if a high cervical transmasseteric anteroparotid approach is used. The retromandibular transparotid approach gives direct access to the fractured area and is the only incision that is close to the fracture line. The facial nerve divides into the temporofacial branch (consisting of the temporal and zygomatic branches) and the cervicofacial branch (the buccal, marginal mandibular, and cervical branches). The window between the buccal and marginal mandibular branches is the area of dissection. The superior margin of incision is required to be retracted more for plating or for locating the medial overlapping condyle. This may the reason for the increased incidence of neuropraxia in the buccal branch that was not found in the studies of Ellis and Dean8 and Manisali et al.13 Similar high incidences of buccal nerve palsy were also reported by Vesnaver et al.5 and Hyde et al.14 It is possible to reduce
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
ARTICLE IN PRESS
YBJOM-4153; No. of Pages 5
4
O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
Table 2 Reported incidences and sites of damage to the facial nerve. First author and reference no.
Year
No. of patients
No. of sites
No. (%) with transient facial nerve palsy
Branches affected
Ellis8 Ellis7
1993 2000
Not stated 83
29 83
14 (48) 16 (19)
Hyde14 Manisali13
2002 2003
25 20
25 20
3 6
Vesnaver5
2005
34
36
8 (22)
Downie15
2009
50
51
7 (14)
Yang16
2012
42
48
8 (18)
38
44
9 (20)
Marginal mandibular Marginal mandibular, buccal, n = 5, periorbital, n = 2 Buccal Marginal mandibular, n = 6, buccal, n = 1 Buccal, or zygomatic, or both Buccal, n = 4, zygomatic, n = 3 Buccal, or zygomatic, or both Buccal, n = 7, marginal mandibular, n = 2, zygomatic, n = 1
Present study
the incidence of buccal nerve palsy by dissecting the nerve and protecting it from retraction with a suitable instrument. We made no attempt to visualise the nerve during dissection, but if we encountered it we retracted it away from the site. To minimise the amount of retraction needed, particularly in medially-displaced condylar fragments, a vertical subsigmoid osteotomy could be made so that the medial condyle could be located and fixated extracorporeally as shown by Ellis and Dean.8 The cut bone would be devoid of periosteal and muscular attachments and would act as a non-vascularised bone graft plated to the ramus. Zygomatic nerve palsy was seen in one patient with a medially dislocated condyle, and we encountered extreme difficulty during reduction of the fractured segments as they required more retraction of soft tissue over a longer period,
which resulted in retraction paralysis of this branch. The facial nerve palsies that took longest to recover were associated with medially displaced condylar fractures, where longer operating time and more retraction of soft tissues were required to locate and retrieve the fragments, and this probably resulted in traction neuropraxia of the facial nerve. In neuropraxia functional recovery takes place within 0–12 weeks. However, during the postoperative period as oedema increases the inflow of nutrients to the nerve decreases. This results in axonal death (axonotmesis) and retrograde degeneration. However, the endoneurium in this type of injury is intact and axons will regrow through the channels, and this results in late recovery of function (3–6 months).23 A similar recovery pattern was seen in the present series. The transient palsy was probably the result of excessive retraction
Table 3 Reported duration of recovery after damage to the facial nerve. First author and reference no.
Year
Branches affected
Duration of recovery
Time until full recovery
Ellis8
1993
Marginal mandibular
All within 16 weeks
Ellis7
2000
6 weeks, transient palsy of all branches
Hyde14 Manisali13
2002 2003
Vesnaver5
2005
Marginal mandibular, buccal, n = 5, periorbital, n = 2 Buccal Marginal mandibular, n = 6, buccal, n = 1 Buccal, or zygomatic, or both
No case of total paralysis All within 6 months
Downie15
2009
–
Yang16
2012
Buccal, n = 4, zygomatic, n = 3 Buccal, or zygomatic, or both Buccal, n = 7, marginal mandibular, n = 2, zygomatic, n = 1
Present study
– 2 within 1 month
1 month All within 3 months
6 within 4–8 weeks
All within 2–4 weeks
1 mild weakness of upper lip and lower eyelid at 13 months All within 5–15 months 1 month
7 within 3 months
All within 6 months
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
YBJOM-4153; No. of Pages 5
ARTICLE IN PRESS O. Bhutia et al. / British Journal of Oral and Maxillofacial Surgery xxx (2013) xxx–xxx
rather than neurotomesis. The mean duration of recovery was 12 weeks (Table 3). The parotid fistulas were managed by local dressings, having been the result of inadequate closure of the parotid capsule as also reported by Vesnaver et al.5 Water tight closure of the parotid capsule is recommended. The retromandibular transparotid approach is useful for treating undisplaced and laterally displaced subcondylar fractures, and it has the advantages of direct access to the fracture site, an inconspicuous scar, no permanent damage to the facial nerve, and easy open reduction and internal fixation. There may be a high incidence of transient nerve palsy but permanent damage has not been reported to our knowledge. When this approach is used for ORIF of subcondylar fractures care should be taken to be gentle when retracting soft tissues. There is a role for preoperative and postoperative counselling of patients who opt for this approach about temporary facial nerve palsy.
Sources of support in the form of grants No sources of support in the form of grants.
Competing interests None declared.
Ethical approval Approved by Institutional Ethical Committee.
References 1. Rowe NL, Killey HC, editors. Fractures of the facial skeleton. 2nd ed. Edinburgh: Churchill Livingstone; 1968. p. 80–92. 2. Silvennoinen U, Iizuka T, Lindquist C, et al. Different patterns of condylar fractures: an analysis of 382 patients in a 3-year period. J Oral Maxillofac Surg 1992;50:1032–7. 3. Takenoshita Y, Ishibashi H, Oka M. Comparison of functional recovery after nonsurgical and surgical treatment of condylar fractures. J Oral Maxillofac Surg 1990;48:1191–5. 4. Konstantinovic VS, Dimitrijevic B. Surgical versus conservative treatment of unilateral condylar process fractures: clinical and radiographic evaluation of 80 patients. J Oral Maxillofac Surg 1992;50:349–52.
5
5. Vesnaver A, Gorjanc M, Eberlinc A, et al. The preauricular transparotid approach for open reduction and internal fixation of condylar fractures. J Craniomaxillofac Surg 2005;33:169–79. 6. Chossegros C, Cheynet F, Blanc L, et al. Short retromandibular approach of subcondylar fractures – clinical and radiologic long term evaluation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82:248–52. 7. Ellis III E, McFadden D, Simon P, et al. Surgical complications with open treatment of mandibular condylar process fractures. J Oral Maxillofac Surg 2000;58:950–8. 8. Ellis III E, Dean J. Rigid fixation of mandibular condylar fractures. Oral Surg Oral Med Oral Pathol 1993;76:6–15. 9. Ellis III E, Zide MF. Transfacial approaches to the mandible. In: Ellis III E, Zide MF, Manson PN, editors. Surgical approaches to facial skeleton. Baltimore: Lippincott Willams & Wilkins; 1995. p. 123–85. 10. Hinds E, Girotti W. Vertical subcondylar osteotomy: a reappraisal. J Oral Surg 1967;24:164–70. 11. Koberg WR, Momma W. Treatment of fractures of the mandibular process by functional stable osteosynthesis using miniaturized dynamic compression plates. Int J Oral Surg 1978;7:256–62. 12. Zide MF, Kent JN. Indication for open reduction of mandibular condyle fractures. J Oral Maxillofac Surg 1983;41:89–98. 13. Manisali M, Amin M, Aghabeigi B, et al. Retromandibular approach to the mandibular condyle: a clinical and cadaveric study. Int J Oral Maxillofac Surg 2003;32:253–6. 14. Hyde N, Manisali M, Aghabeigi B, et al. The role of open reduction and internal fixation in unilateral fractures of the mandibular condyles: a prospective study. Br J Oral Maxillofac Surg 2002;40:19–22. 15. Downie JJ, Devlin MF, Carton AT, et al. Prospective study of morbidity associated with open reduction and internal fixation of the fractured condyle by the transparotid approach. Br J Oral Maxillofac Surg 2009;47:370–3. 16. Yang L, Patil PM. The retromandibular transparotid approach to mandibular subcondylar fractures. Int J Oral Maxillofac Surg 2012;41:494–9. 17. Hammer B, Schier P, Prein J. Osteosynthesis of condylar neck fractures: a review of 30 patients. Br J Oral Maxillofac Surg 1997;35:288–91. 18. Widmark G, Bagenholm T, Kahnberg KE, et al. Open reduction of subcondylar fractures. A study of functional rehabilitation. Int J Oral Maxillofac Surg 1996;25:107–11. 19. Haug RH, Brandt MT. Traditional versus endoscope-assisted open reduction with rigid internal fixation (ORIF) of adult mandibular condyle fractures: a review of the literature regarding current thoughts on management. J Oral Maxillofac Surg 2004;62:1272–9. 20. Wilson AW, Ethunandan M, Brennan PA. Transmasseteric antero-parotid approach for open reduction and internal fixation of condylar fractures. Br J Oral Maxillofac Surg 2005;43:57–60. 21. Trost O, Abu El-Naaj I, Trouilloud P, et al. High cervical transmasseteric anteroparotid approach for open reduction and internal fixation of condylar fracture. J Oral Maxillofac Surg 2008;66:201–4. Erratum: J Oral Maxillofac Surg 2008;66:607. 22. Trost O, Trouilloud P, Malka G. Open reduction and internal fixation of low subcondylar fractures of mandible through high cervical transmasseteric anteroparotid approach. J Oral Maxillofac Surg 2009;67:2446–51. 23. Selesnick SH, Patwardhan A. Acute facial paralysis: evaluation and early management. Am J Otolaryngol 1994;15:387–408.
Please cite this article in press as: Bhutia O, et al. Evaluation of facial nerve following open reduction and internal fixation of subcondylar fracture through retromandibular transparotid approach. Br J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.bjoms.2013.12.002
