Vol. 117 No. 3 March 2014
A new surgical approach to treat medial or low condylar fractures: the minor parotid anterior approach Jia Hou, DMD,1 Lin Chen, DMD,1 Tingting Wang, DMD, Wei Jing, MD, Wei Tang, MD, Jie Long, MD, Weidong Tian, MD, DMD, and Lei Liu, MD, DMD West China Hospital of Stomatology, Sichuan University, Chengdu, China
Objective. A new surgical approach, denoted as the minor parotid anterior approach, was designed to treat medial or low mandibular condylar fractures. Study Design. Sixty patients (72 sides) with medial or low condylar fractures were treated surgically. Thirty-six patients (42 sides) were treated with the minor parotid anterior approach, and 24 patients (30 sides) were treated with a retromandibular approach. Data on the surgical procedures and complications were recorded. The follow-up period was 3 to 12 months. Results. Four patients suffered facial nerve injury in the group treated with the retromandibular approach. No cases of facial nerve injury occurred in the minor parotid anterior approach group. Conclusions. The minor parotid anterior approach avoided facial nerve injury, resulted in less visible facial scarring, and required less manipulation time. Therefore, the minor parotid anterior approach is worth application in the clinical setting. (Oral Surg Oral Med Oral Pathol Oral Radiol 2014;117:283-288)
One-third of all mandibular fractures involve the condylar region.1-3 Condylar fractures usually result in malocclusion, limited mouth opening, and dysmasesia, which cause serious problems in patients’ daily and social lives. Even when condylar fractures are surgically repaired, there remains a possibility of dysfunction of the temporomandibular joint, condylar deformity, and limited mouth opening. Therefore, the treatment of condylar fractures remains a great challenge to surgeons. With recent developments in medical imaging and internal fixation materials technology, open reduction and internal fixation (ORIF) has become the main treatment of condylar fractures. Surgery has become the preferred treatment, especially for medial or low condylar fractures. Surgical repair of condylar fractures must follow 3 rulesdprecise reduction, reliable fixation, and minimal damage4dand the choice of approach is the first issue. There are many complex anatomic structures around the condyle, such as the parotid gland, facial nerve, superficial temporal vessels, and maxillary vessels. Compared with other maxillofacial fractures, condylar fractures are more difficult to expose. As a result, many surgical approaches have been used to meet the principle of 1 Jia Hou and Lin Chen contributed equally to this article. This study was supported by the National Natural Foundation of China (81070802, 81271096), the Research Fund for the Doctoral Program of Higher Education of China (20090181110057), and the Fundamental Research Funds for the Central Universities of China. Trial Registration: Clinicaltrials.gov (NCT01851031). Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University. Received for publication May 14, 2013; returned for revision Sep 6, 2013; accepted for publication Nov 1, 2013. Crown Copyright Ó 2014 Published by Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter http://dx.doi.org/10.1016/j.oooo.2013.11.491
SEOA (safe, good exposure, easy surgical procedure, aesthetics). Several different approaches for the treatment of dislocated condylar fractures have been used, including the preauricular approach, the submandibular approach, the intraoral approach, and the retromandibular approach.5 Thoma6 described the classic preauricular approach in 1945. The incision is in the preauricular skin crease anterior to the tragus. The skin flap is reflected anteriorly after the incision, and careful dissection is necessary to avoid damage to the temporal branch of the facial nerve. The temporal fascia is cut to expose the superficial temporal artery, and the temporal branch is dissected along the plane of the earlobe, thus protecting the facial nerve. The joint capsule and periosteum are then cut, and ORIF is performed once the fracture site is exposed. The preauricular approach has long been advocated by surgeons for the treatment of high condylar fractures.7-9 The advantages of the preauricular approach are obvious, such as direct vision of the fracture site and ease of manipulation of the condyle.6 Especially for the high condylar fractures, this approach provides better exposure of the fracture fragments and reduction. However, there are
Statement of Clinical Relevance A new surgical approach, denoted as the minor parotid anterior approach, was designed to treat medial or low condylar fractures. The results showed the new approach avoided facial nerve injury, resulted in less visible scarring, and required less manipulation time. 283
ORAL AND MAXILLOFACIAL SURGERY 284 Hou et al.
several disadvantages. First, the medial and low condylar regions are difficult to expose adequately using this approach, and an additional incision is occasionally required to obtain satisfactory reduction and fixation.10 Second, trauma to this area may lead to some complications, such as injury to the temporal branch of the facial nerve and severe hemorrhage. Therefore, the preauricular approach is mainly used for high or medial condylar fractures, and especially for high fractures. The submandibular approach was first described by Perthes in 1924.11 Both Thoma6 and Henny12 reported reduction of a subcondylar fracture through a modified submandibular approach in 1951, but the classic submandibular approach was described by Malkin13 in 1964. In this approach, a slightly curved submandibular incision is made from just below the earlobe to 2.5 cm anterior to the angle of the mandible, parallel to and 1 cm below the border of the mandible. The dissection is continued through the platysma muscle and the subcutaneous tissue to the masseter muscle at the inferior border of the mandible. The masseter muscle and the periosteum are reflected from the ramus to expose the fracture site, and the fracture is then reduced and fixed. Compared with the preauricular approach, the condylar head and temporomandibular joint need not be involved in the dissection using the submandibular approach unless the head of the condyle is displaced from the fossa or is fractured, and this approach is also a short procedure.13 In the past, the submandibular approach was the first option for a surgical procedure for subcondylar fractures,14 and it is still used by some surgeons.15 However, the submandibular approach also has some disadvantages. The main problems with this approach are the probability of injury to the marginal mandibular branch of the facial nerve and that the fracture fragments can only be well exposed with a long incision. Moreover, the surgical procedures can sometimes be very difficult because of the extended distance from the incision to the fracture site, especially for high condylar fractures.4 The retromandibular approach was first proposed by Hinds and Girotti in 1967.16 The incision is parallel to the posterior border of the mandible; it begins just 0.5 cm below the earlobe and continues inferiorly 3 to 3.5 cm. The line of incision is through the masseter muscle, traversing the parotid gland from its posterior or inferior lobe to expose the fracture site to allow for ORIF. Compared with the previous approaches, the retromandibular approach is favored by many surgeons because it has the following advantages: it is closer to the condylar process, and it provides better exposure of the fracture ends and the posterior edge of the ramus.16,17 Ellis and Dean5 reported that the retromandibular approach was their favored approach and it
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was used in the vast majority of their surgical procedures. However, extensive clinical experience showed that the retromandibular approach had the disadvantages of facial nerve injury, salivary fistula, and visible scars. In general, the preauricular, retromandibular, and submandibular approaches provide very good results and are useful for condylar fractures. Meanwhile, they also have some disadvantages, such as injury of the facial nerve, visible scars, salivary fistula, and a large amount of surgical trauma.18 Thus there is still a need to design a new and better approach for condylar fractures. Currently, surgeons are using more minimally invasive surgery (MIS). Initially, surgeons used an intraoral approach for ORIF in condylar fractures, which was considered revolutionary. The approach was first described by Silverman,19 and Steinhauser20 was the first to report a successful osteosynthesis using an intraoral incision. The approach has been used more frequently since that time.5,21 The intraoral approach requires an incision through the vestibular mucosa along the anterior edge of the ascending ramus.21 The temporalis muscle is stripped from the anterior border of the ascending ramus, and the masseter is stripped by subperiosteal dissection.5 ORIF is performed using a transbuccal trocar or, alternatively, an angled screwdriver. Endoscopy is required for reduction and fixation because the posterior edge of the ascending ramus cannot be inspected unaided. The advantages of this approach are apparent. It does not cause a visible facial scar, and there is no risk of damage to the facial nerve. The technology fully embodies the characteristics of MIS, and it is the future surgical trend. However, as the approach gained clinical use, surgeons found that the approach had several limitations and strict indications. The major disadvantage of this approach is limited access, and it is difficult to reduce some fractures as a result, especially those that are displaced to the medial side of the mandible.5 Complications such as loosening of plates and secondary displacement have also occurred, owing to a restricted view and inadequate osteosynthesis.22 An added disadvantage is that the specialized instruments, the need for endoscopy, and the advanced surgical technology increase the difficulty. Therefore, the intraoral approach should be used only in cases where it is clearly indicated, such as subcondylar fractures with minimal dislocation. For condylar fractures with serious dislocation, medial dislocation, or comminution, an external application is still necessary. Although there have been many surgical approaches used for the treatment of the medial or low condylar fractures, all have their distinct disadvantages. Therefore, the authors designed a new approach to treat medial or low condylar fractures: the minor parotid anterior approach. We compared this new approach
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ORIGINAL ARTICLE Hou et al. 285
Fig. 1. Line drawings of the minor parotid anterior approach. A, The incision. B, The anteroinferior edge of the parotid gland was exposed. C, The parotid gland was retracted backward and upward so that the masseter muscle attached on the surface of the mandibular ramus could be exposed. D, Exposure of the fracture site. E, Reduction and fixation of the fragments.
with the retromandibular approach to evaluate its therapeutic effect and advantages.
PATIENTS AND METHODS Ethical approval for the study was obtained from the Research Ethics Board of the Ethics Committee, West China Hospital of Stomatology, Sichuan University. All patients fulfilled the following inclusion criteria: (1) clinical and imaging diagnosis of medial or low condylar fractures; (2) obviously dislocated bone fragments affecting the patients’ appearance and function and requiring surgical intervention; and (3) no previous surgical treatment. Exclusion criteria were (1) medial or low condylar fractures without obvious displacement; (2) previous unsuccessful surgery; and (3) a traumatic scar at the planned surgical site, preventing the usual placement of the incision. All patients were treated under general anesthesia with nasotracheal intubation. When repairing coexistent fractures, with a need to expose the maxilla and the zygomatic arch, we used an auxiliary incision, such as the intraoral vestibular incision or the coronal incision. Sixty patients with medial or low condylar fractures (72 sides) from February 2009 to June 2012 were enrolled into this study. Patients ranged in age from 5 to 56 years (average, 32.5 years). Patients were randomly divided into 2 groups: 36 patients (42 sides) received the minor parotid anterior approach, and 24 patients
(30 sides) received the retromandibular approach. All medical records were collected. The patients were followed up for 3 months. Data related to these visits were recorded for outcomes and analysis of the related complications. On admission, all patients underwent preoperative and postoperative imaging, including preoperative and postoperative radiography or computed tomography. Experimental group of 36 cases treated with the minor parotid anterior approach The incision extended from the tragus, beginning 1 cm above the fracture line and continuing inferiorly 2 to 2.5 cm (Figure 1, A, and Figure 2, A), which is close to the earlobe and almost in parallel with the ramus of the mandible. The skin, subcutaneous tissue, and superficial fascia were retracted forward and downward until the anteroinferior edge of the parotid gland (which is between the low buccal branch and the marginal mandibular branch of the facial nerve) was exposed clearly (see Figure 1, B, and Figure 2, B). Then, blunt dissection was performed between the parotid gland and the masseter muscle so that the parotid gland could be retracted easily backward and upward. At this time, the masseter muscle attached on the surface of the mandibular ramus could be exposed clearly (see Figure 1, C, and Figure 2, C). The masseter could be cut longitudinally to expose the fracture site using an electrotome (see Figure 1, D, and
ORAL AND MAXILLOFACIAL SURGERY 286 Hou et al.
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Fig. 2. Surgical photographs of the minor parotid anterior approach. A, The incision. B, Exposed the anteroinferior edge of the parotid gland. C, The parotid gland was retracted backward and upward so that the masseter muscle attached on the surface of the mandibular ramus could be exposed. D, Exposure of the fracture site. E, Reduction and fixation of the fragments. F, The minor parotid anterior incision was sutured.
Figure 2, D). ORIF could be performed under direct vision (see Figure 1, E, and Figure 2, E). The fracture site was then irrigated and sutured (see Figure 2, F), with suture removal occurring after 7 days. Postoperatively, early training for active and passive mouth opening was conducted. All of the patients were followed up for 3 months to evaluate prognoses and the frequency of complications. Control group of 24 cases treated with the retromandibular approach The retromandibular approach was used as previously described. The incision was parallel to the posterior border of the mandible, beginning 0.5 cm below the earlobe and continuing inferiorly 3 to 3.5 cm, through the masseter muscle, traversing the parotid gland from its posterior or inferior lobe to expose the fracture site, allowing for rigid internal fixation. After the completion of the internal fixation, the management of the patients was similar to that in the group with the minor parotid anterior approach.
RESULTS All 60 enrolled patients completed the study, and all of the surgical procedures were finished successfully. The reductions were ideal, and the fixations were reliable. Most patients experienced significant improvement with respect to both aesthetic appearance and function, and none of the common complications (such as hemorrhage, malocclusion, and infection) occurred. The postoperative gape degree of all patients was well
recovered. No cases of facial nerve injury were observed in the minor parotid anterior approach group. Four patients suffered injuries to the marginal mandibular branch of the facial nerve in the retromandibular approach group, one of which was permanent. Because the incision was short and located in the skin wrinkles, the facial scar was less visible in the minor parotid anterior approach group than in the retromandibular approach group. The average surgical procedure time was approximately 55 minutes in the minor parotid anterior approach group, significantly shorter than the 85 minutes in the retromandibular approach group. Salivary fistula occurred in 1 patient in the minor parotid anterior approach group and in 2 patients in the other group. There were no other complications in either group.
DISCUSSION MIS is the surgical trend in the 21st century, and with it, the use of small incisions is increasing. The advantages of small incisions are apparent and include less surgical trauma, less bleeding, fewer and smaller scars, good aesthetics, and reduction of infection risk. The number of days in the hospital is significantly shorter, and manpower and material resources are saved. Because of this trend to smaller incisions, the authors designed the minor parotid anterior approach to treat medial or low condylar fractures. There is a potential anatomic space in the parotideomasseteric region between the parotid myofascial tissue and the superficial fascia. Using the minor parotid anterior approach, the skin, subcutaneous tissue, and
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superficial fascia can be pulled forward 2 to 3 cm, which is enough to reach the anteroinferior edge of the parotid gland. The approach also provides potential clearance between the parotid gland and the masseter to allow the parotid tissue to be pulled backward to expose the masseter overlying the fracture site. The medial and low areas of the condyle can be exposed under direct vision when the masseter and periosteum are cut, thereby increasing the ease of ORIF. In our study, 36 patients with medial or low condylar fractures were treated using this approach, and we obtained ideal reduction and fixation with minimal complications, confirming its usefulness. The minor parotid anterior approach has obvious advantages. The first is that the marginal branch of the facial nerve is not injured unless patients have marked facial anatomic variation. In this study, no patients suffered damage to the marginal branch of the facial nerve in the minor parotid anterior approach group. However, 4 patients in the retromandibular approach group did suffer marginal mandibular branch injury. Anatomically, the most likely section of the facial nerve to sustain damage with the minor parotid anterior approach is the low buccal branch. Damage to the marginal branch causes drooping on the affected side of the face, which greatly affects the patients’ appearance. In contrast, damage to the low buccal branch has little clinical effect. Also, the upper and lower buccal branches act similarly, so that even if the buccal branch was injured inadvertently, other branches can compensate. The second main advantage of the minor parotid anterior approach is that the length of its incision is from 2 to 2.5 cm, compared with 3 to 3.5 cm in the retromandibular approach. The shorter incision produces less scarring. Scars were not obvious 3 months after the surgical procedures in our study in the minor parotid anterior approach group, with almost no effect on the appearance of the patients. The third main advantage of the minor parotid anterior approach is that although its incision is minor, the location overlies the fracture site and provides the surgeon with excellent visual exposure of the fracture fragments, much better than with the retromandibular approach. The surgical procedure is simple and quick, because the approach avoids important anatomic structures. The operating time is shortened, and the approach better reflects the characteristics of MIS.
CONCLUSIONS In conclusion, the minor parotid anterior approach has many advantages: good exposure, minimal scar, simple manipulation, short operating time, and minimal risk to the facial nerve. Therefore, it is the best choice for
ORIGINAL ARTICLE Hou et al. 287
medial or low condylar fractures and is worthy of application in the clinical setting. We deeply thank the patients and their families for participation in the study.
REFERENCES 1. Oji C. Jaw fractures in Enugu, Nigeria, 1985-95. Br J Oral Maxillofac Surg. 1999;37:106-109. 2. Devlin MF, Hislop WS, Carton AT. Open reduction and internal fixation of fractured mandibular condyles by a retromandibular approach: surgical morbidity and informed consent. Br J Oral Maxillofac Surg. 2002;40:23-25. 3. Marker P, Nielsen A, Bastian HL. Fractures of the mandibular condyle, part 1: patterns of distribution of types and causes of fractures in 348 patients. Br J Oral Maxillofac Surg. 2000;38: 417-421. 4. Ellis E 3rd, Throckmorton GS, Palmieri C. Open treatment of condylar process fractures: assessment of adequacy of repositioning and maintenance of stability. J Oral Maxillofac Surg. 2000;58:27-34;discussion 35. 5. Ellis E, Dean J. Rigid fixation of mandibular condylar fractures. Oral Surg Oral Med Oral Pathol. 1993;76:6-15. 6. Thoma KH. Fractures and fracture dislocations of the mandibular condyle: a method for open reduction and internal wiring and one for skeletal fixation, with a report of thirty-two cases. J Oral Surg. 1945;3:3-19. 7. Peters RA, Caldwell JB, Olsen TW. A technique for open reduction of subcondylar fractures. Oral Surg Oral Med Oral Pathol. 1976;41:273-280. 8. MacArthur CJ, Donald PJ, Knowles J, Moore HC. Open reduction fixation of mandibular subcondylar fractures. Arch Otolaryngol Head Neck Surg. 1993;119:403-406. 9. Pereira MD, Marques A, Ishizuka M, Keira SM, Brenda E, Wolosker AB. Surgical treatment of the fractured and dislocated condylar process of the mandible. J Craniomaxillofac Surg. 1995;23:369-376. 10. Takenoshita Y, Oka M, Tashiro H. Surgical treatment of fractures of the mandibular condylar neck. J Craniomaxillofac Surg. 1989;17:119-124. 11. Perthes G. Uber Frakturen und Luxationsfrakturen des Kiefergelenkkopfchens und ihre operative Behandlung. Verh Dtsch Ges. 1924;133:418-434. 12. Henny FA. A technique for open reduction of fractures of the mandibular condyle. J Oral Surg. 1951;9:233-237. 13. Malkin M, Kresberg H, Mandel L. Submandibular approach for open reduction of condylar fracture. Oral Surg Oral Med Oral Pathol. 1964;17:152-157. 14. Chossegros C, Cheynet F, Blanc JL, Bourezak Z. Short retromandibular approach to subcondylar fractures: clinical and radiologic long-term evaluation. Oral Surg Oral Med Oral Path Oral Radiol Endod. 1996;82:248-252. 15. Eckelt U. Fractures of the mandibular condyle. Mund Kiefer Gesichtschir. 2000;4:S110-S117 [review] [in German]. 16. Hinds EC, Girotti WJ. Vertical subcondylar osteotomy: a reappraisal. J Oral Surg. 1967;24:164-170. 17. Tang W, Gao C, Long J, et al. Application of modified retromandibular approach indirectly from the anterior edge of the parotid gland in the surgical treatment of condylar fracture. J Oral Maxillofac Surg. 2009;67:552-558. 18. Weinberg MJ, Merx P, Antonyshyn O, Farb R. Facial nerve palsy after mandibular fractures. Ann Plast Surg. 1995;34:546-549 [review].
ORAL AND MAXILLOFACIAL SURGERY 288 Hou et al. 19. Silverman SL. A new operation for displaced fractures at the neck of the mandibular condyle. Dental Cosmos. 1925;67: 876-877. 20. Steinhauser E. Eingriffe am Processus articularis auf dem oralen Weg. Dtsch Zahnarztl Z. 1964;19:694-700. 21. Hochban W, Ellers M, Umstadt HE, Juchems KI. Zur operativen reposition und fixation von unterkiefergelenkfortsatzfrakturen von enoral. Fortschr Kiefer Gesichtschir. 1996;41: 80-85. 22. Schneider M, Lauer G, Eckelt U. Surgical treatment of fractures of the mandibular condyle: a comparison of long-term results following different approachesdfunctional, axiographical, and
OOOO March 2014 radiological findings. J Craniomaxillofac Surg. 2007;35: 151-160. Reprint requests: Lei Liu Department of Oral and Maxillofacial Surgery West China Hospital of Stomatology Sichuan University Chengdu 610041 China [email protected]
A new surgical approach to treat medial or low condylar fractures: the minor parotid anterior approach Jia Hou, DMD,1 Lin Chen, DMD,1 Tingting Wang, DMD, Wei Jing, MD, Wei Tang, MD, Jie Long, MD, Weidong Tian, MD, DMD, and Lei Liu, MD, DMD West China Hospital of Stomatology, Sichuan University, Chengdu, China
Objective. A new surgical approach, denoted as the minor parotid anterior approach, was designed to treat medial or low mandibular condylar fractures. Study Design. Sixty patients (72 sides) with medial or low condylar fractures were treated surgically. Thirty-six patients (42 sides) were treated with the minor parotid anterior approach, and 24 patients (30 sides) were treated with a retromandibular approach. Data on the surgical procedures and complications were recorded. The follow-up period was 3 to 12 months. Results. Four patients suffered facial nerve injury in the group treated with the retromandibular approach. No cases of facial nerve injury occurred in the minor parotid anterior approach group. Conclusions. The minor parotid anterior approach avoided facial nerve injury, resulted in less visible facial scarring, and required less manipulation time. Therefore, the minor parotid anterior approach is worth application in the clinical setting. (Oral Surg Oral Med Oral Pathol Oral Radiol 2014;117:283-288)
One-third of all mandibular fractures involve the condylar region.1-3 Condylar fractures usually result in malocclusion, limited mouth opening, and dysmasesia, which cause serious problems in patients’ daily and social lives. Even when condylar fractures are surgically repaired, there remains a possibility of dysfunction of the temporomandibular joint, condylar deformity, and limited mouth opening. Therefore, the treatment of condylar fractures remains a great challenge to surgeons. With recent developments in medical imaging and internal fixation materials technology, open reduction and internal fixation (ORIF) has become the main treatment of condylar fractures. Surgery has become the preferred treatment, especially for medial or low condylar fractures. Surgical repair of condylar fractures must follow 3 rulesdprecise reduction, reliable fixation, and minimal damage4dand the choice of approach is the first issue. There are many complex anatomic structures around the condyle, such as the parotid gland, facial nerve, superficial temporal vessels, and maxillary vessels. Compared with other maxillofacial fractures, condylar fractures are more difficult to expose. As a result, many surgical approaches have been used to meet the principle of 1 Jia Hou and Lin Chen contributed equally to this article. This study was supported by the National Natural Foundation of China (81070802, 81271096), the Research Fund for the Doctoral Program of Higher Education of China (20090181110057), and the Fundamental Research Funds for the Central Universities of China. Trial Registration: Clinicaltrials.gov (NCT01851031). Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University. Received for publication May 14, 2013; returned for revision Sep 6, 2013; accepted for publication Nov 1, 2013. Crown Copyright Ó 2014 Published by Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter http://dx.doi.org/10.1016/j.oooo.2013.11.491
SEOA (safe, good exposure, easy surgical procedure, aesthetics). Several different approaches for the treatment of dislocated condylar fractures have been used, including the preauricular approach, the submandibular approach, the intraoral approach, and the retromandibular approach.5 Thoma6 described the classic preauricular approach in 1945. The incision is in the preauricular skin crease anterior to the tragus. The skin flap is reflected anteriorly after the incision, and careful dissection is necessary to avoid damage to the temporal branch of the facial nerve. The temporal fascia is cut to expose the superficial temporal artery, and the temporal branch is dissected along the plane of the earlobe, thus protecting the facial nerve. The joint capsule and periosteum are then cut, and ORIF is performed once the fracture site is exposed. The preauricular approach has long been advocated by surgeons for the treatment of high condylar fractures.7-9 The advantages of the preauricular approach are obvious, such as direct vision of the fracture site and ease of manipulation of the condyle.6 Especially for the high condylar fractures, this approach provides better exposure of the fracture fragments and reduction. However, there are
Statement of Clinical Relevance A new surgical approach, denoted as the minor parotid anterior approach, was designed to treat medial or low condylar fractures. The results showed the new approach avoided facial nerve injury, resulted in less visible scarring, and required less manipulation time. 283
ORAL AND MAXILLOFACIAL SURGERY 284 Hou et al.
several disadvantages. First, the medial and low condylar regions are difficult to expose adequately using this approach, and an additional incision is occasionally required to obtain satisfactory reduction and fixation.10 Second, trauma to this area may lead to some complications, such as injury to the temporal branch of the facial nerve and severe hemorrhage. Therefore, the preauricular approach is mainly used for high or medial condylar fractures, and especially for high fractures. The submandibular approach was first described by Perthes in 1924.11 Both Thoma6 and Henny12 reported reduction of a subcondylar fracture through a modified submandibular approach in 1951, but the classic submandibular approach was described by Malkin13 in 1964. In this approach, a slightly curved submandibular incision is made from just below the earlobe to 2.5 cm anterior to the angle of the mandible, parallel to and 1 cm below the border of the mandible. The dissection is continued through the platysma muscle and the subcutaneous tissue to the masseter muscle at the inferior border of the mandible. The masseter muscle and the periosteum are reflected from the ramus to expose the fracture site, and the fracture is then reduced and fixed. Compared with the preauricular approach, the condylar head and temporomandibular joint need not be involved in the dissection using the submandibular approach unless the head of the condyle is displaced from the fossa or is fractured, and this approach is also a short procedure.13 In the past, the submandibular approach was the first option for a surgical procedure for subcondylar fractures,14 and it is still used by some surgeons.15 However, the submandibular approach also has some disadvantages. The main problems with this approach are the probability of injury to the marginal mandibular branch of the facial nerve and that the fracture fragments can only be well exposed with a long incision. Moreover, the surgical procedures can sometimes be very difficult because of the extended distance from the incision to the fracture site, especially for high condylar fractures.4 The retromandibular approach was first proposed by Hinds and Girotti in 1967.16 The incision is parallel to the posterior border of the mandible; it begins just 0.5 cm below the earlobe and continues inferiorly 3 to 3.5 cm. The line of incision is through the masseter muscle, traversing the parotid gland from its posterior or inferior lobe to expose the fracture site to allow for ORIF. Compared with the previous approaches, the retromandibular approach is favored by many surgeons because it has the following advantages: it is closer to the condylar process, and it provides better exposure of the fracture ends and the posterior edge of the ramus.16,17 Ellis and Dean5 reported that the retromandibular approach was their favored approach and it
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was used in the vast majority of their surgical procedures. However, extensive clinical experience showed that the retromandibular approach had the disadvantages of facial nerve injury, salivary fistula, and visible scars. In general, the preauricular, retromandibular, and submandibular approaches provide very good results and are useful for condylar fractures. Meanwhile, they also have some disadvantages, such as injury of the facial nerve, visible scars, salivary fistula, and a large amount of surgical trauma.18 Thus there is still a need to design a new and better approach for condylar fractures. Currently, surgeons are using more minimally invasive surgery (MIS). Initially, surgeons used an intraoral approach for ORIF in condylar fractures, which was considered revolutionary. The approach was first described by Silverman,19 and Steinhauser20 was the first to report a successful osteosynthesis using an intraoral incision. The approach has been used more frequently since that time.5,21 The intraoral approach requires an incision through the vestibular mucosa along the anterior edge of the ascending ramus.21 The temporalis muscle is stripped from the anterior border of the ascending ramus, and the masseter is stripped by subperiosteal dissection.5 ORIF is performed using a transbuccal trocar or, alternatively, an angled screwdriver. Endoscopy is required for reduction and fixation because the posterior edge of the ascending ramus cannot be inspected unaided. The advantages of this approach are apparent. It does not cause a visible facial scar, and there is no risk of damage to the facial nerve. The technology fully embodies the characteristics of MIS, and it is the future surgical trend. However, as the approach gained clinical use, surgeons found that the approach had several limitations and strict indications. The major disadvantage of this approach is limited access, and it is difficult to reduce some fractures as a result, especially those that are displaced to the medial side of the mandible.5 Complications such as loosening of plates and secondary displacement have also occurred, owing to a restricted view and inadequate osteosynthesis.22 An added disadvantage is that the specialized instruments, the need for endoscopy, and the advanced surgical technology increase the difficulty. Therefore, the intraoral approach should be used only in cases where it is clearly indicated, such as subcondylar fractures with minimal dislocation. For condylar fractures with serious dislocation, medial dislocation, or comminution, an external application is still necessary. Although there have been many surgical approaches used for the treatment of the medial or low condylar fractures, all have their distinct disadvantages. Therefore, the authors designed a new approach to treat medial or low condylar fractures: the minor parotid anterior approach. We compared this new approach
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ORIGINAL ARTICLE Hou et al. 285
Fig. 1. Line drawings of the minor parotid anterior approach. A, The incision. B, The anteroinferior edge of the parotid gland was exposed. C, The parotid gland was retracted backward and upward so that the masseter muscle attached on the surface of the mandibular ramus could be exposed. D, Exposure of the fracture site. E, Reduction and fixation of the fragments.
with the retromandibular approach to evaluate its therapeutic effect and advantages.
PATIENTS AND METHODS Ethical approval for the study was obtained from the Research Ethics Board of the Ethics Committee, West China Hospital of Stomatology, Sichuan University. All patients fulfilled the following inclusion criteria: (1) clinical and imaging diagnosis of medial or low condylar fractures; (2) obviously dislocated bone fragments affecting the patients’ appearance and function and requiring surgical intervention; and (3) no previous surgical treatment. Exclusion criteria were (1) medial or low condylar fractures without obvious displacement; (2) previous unsuccessful surgery; and (3) a traumatic scar at the planned surgical site, preventing the usual placement of the incision. All patients were treated under general anesthesia with nasotracheal intubation. When repairing coexistent fractures, with a need to expose the maxilla and the zygomatic arch, we used an auxiliary incision, such as the intraoral vestibular incision or the coronal incision. Sixty patients with medial or low condylar fractures (72 sides) from February 2009 to June 2012 were enrolled into this study. Patients ranged in age from 5 to 56 years (average, 32.5 years). Patients were randomly divided into 2 groups: 36 patients (42 sides) received the minor parotid anterior approach, and 24 patients
(30 sides) received the retromandibular approach. All medical records were collected. The patients were followed up for 3 months. Data related to these visits were recorded for outcomes and analysis of the related complications. On admission, all patients underwent preoperative and postoperative imaging, including preoperative and postoperative radiography or computed tomography. Experimental group of 36 cases treated with the minor parotid anterior approach The incision extended from the tragus, beginning 1 cm above the fracture line and continuing inferiorly 2 to 2.5 cm (Figure 1, A, and Figure 2, A), which is close to the earlobe and almost in parallel with the ramus of the mandible. The skin, subcutaneous tissue, and superficial fascia were retracted forward and downward until the anteroinferior edge of the parotid gland (which is between the low buccal branch and the marginal mandibular branch of the facial nerve) was exposed clearly (see Figure 1, B, and Figure 2, B). Then, blunt dissection was performed between the parotid gland and the masseter muscle so that the parotid gland could be retracted easily backward and upward. At this time, the masseter muscle attached on the surface of the mandibular ramus could be exposed clearly (see Figure 1, C, and Figure 2, C). The masseter could be cut longitudinally to expose the fracture site using an electrotome (see Figure 1, D, and
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Fig. 2. Surgical photographs of the minor parotid anterior approach. A, The incision. B, Exposed the anteroinferior edge of the parotid gland. C, The parotid gland was retracted backward and upward so that the masseter muscle attached on the surface of the mandibular ramus could be exposed. D, Exposure of the fracture site. E, Reduction and fixation of the fragments. F, The minor parotid anterior incision was sutured.
Figure 2, D). ORIF could be performed under direct vision (see Figure 1, E, and Figure 2, E). The fracture site was then irrigated and sutured (see Figure 2, F), with suture removal occurring after 7 days. Postoperatively, early training for active and passive mouth opening was conducted. All of the patients were followed up for 3 months to evaluate prognoses and the frequency of complications. Control group of 24 cases treated with the retromandibular approach The retromandibular approach was used as previously described. The incision was parallel to the posterior border of the mandible, beginning 0.5 cm below the earlobe and continuing inferiorly 3 to 3.5 cm, through the masseter muscle, traversing the parotid gland from its posterior or inferior lobe to expose the fracture site, allowing for rigid internal fixation. After the completion of the internal fixation, the management of the patients was similar to that in the group with the minor parotid anterior approach.
RESULTS All 60 enrolled patients completed the study, and all of the surgical procedures were finished successfully. The reductions were ideal, and the fixations were reliable. Most patients experienced significant improvement with respect to both aesthetic appearance and function, and none of the common complications (such as hemorrhage, malocclusion, and infection) occurred. The postoperative gape degree of all patients was well
recovered. No cases of facial nerve injury were observed in the minor parotid anterior approach group. Four patients suffered injuries to the marginal mandibular branch of the facial nerve in the retromandibular approach group, one of which was permanent. Because the incision was short and located in the skin wrinkles, the facial scar was less visible in the minor parotid anterior approach group than in the retromandibular approach group. The average surgical procedure time was approximately 55 minutes in the minor parotid anterior approach group, significantly shorter than the 85 minutes in the retromandibular approach group. Salivary fistula occurred in 1 patient in the minor parotid anterior approach group and in 2 patients in the other group. There were no other complications in either group.
DISCUSSION MIS is the surgical trend in the 21st century, and with it, the use of small incisions is increasing. The advantages of small incisions are apparent and include less surgical trauma, less bleeding, fewer and smaller scars, good aesthetics, and reduction of infection risk. The number of days in the hospital is significantly shorter, and manpower and material resources are saved. Because of this trend to smaller incisions, the authors designed the minor parotid anterior approach to treat medial or low condylar fractures. There is a potential anatomic space in the parotideomasseteric region between the parotid myofascial tissue and the superficial fascia. Using the minor parotid anterior approach, the skin, subcutaneous tissue, and
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superficial fascia can be pulled forward 2 to 3 cm, which is enough to reach the anteroinferior edge of the parotid gland. The approach also provides potential clearance between the parotid gland and the masseter to allow the parotid tissue to be pulled backward to expose the masseter overlying the fracture site. The medial and low areas of the condyle can be exposed under direct vision when the masseter and periosteum are cut, thereby increasing the ease of ORIF. In our study, 36 patients with medial or low condylar fractures were treated using this approach, and we obtained ideal reduction and fixation with minimal complications, confirming its usefulness. The minor parotid anterior approach has obvious advantages. The first is that the marginal branch of the facial nerve is not injured unless patients have marked facial anatomic variation. In this study, no patients suffered damage to the marginal branch of the facial nerve in the minor parotid anterior approach group. However, 4 patients in the retromandibular approach group did suffer marginal mandibular branch injury. Anatomically, the most likely section of the facial nerve to sustain damage with the minor parotid anterior approach is the low buccal branch. Damage to the marginal branch causes drooping on the affected side of the face, which greatly affects the patients’ appearance. In contrast, damage to the low buccal branch has little clinical effect. Also, the upper and lower buccal branches act similarly, so that even if the buccal branch was injured inadvertently, other branches can compensate. The second main advantage of the minor parotid anterior approach is that the length of its incision is from 2 to 2.5 cm, compared with 3 to 3.5 cm in the retromandibular approach. The shorter incision produces less scarring. Scars were not obvious 3 months after the surgical procedures in our study in the minor parotid anterior approach group, with almost no effect on the appearance of the patients. The third main advantage of the minor parotid anterior approach is that although its incision is minor, the location overlies the fracture site and provides the surgeon with excellent visual exposure of the fracture fragments, much better than with the retromandibular approach. The surgical procedure is simple and quick, because the approach avoids important anatomic structures. The operating time is shortened, and the approach better reflects the characteristics of MIS.
CONCLUSIONS In conclusion, the minor parotid anterior approach has many advantages: good exposure, minimal scar, simple manipulation, short operating time, and minimal risk to the facial nerve. Therefore, it is the best choice for
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medial or low condylar fractures and is worthy of application in the clinical setting. We deeply thank the patients and their families for participation in the study.
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OOOO March 2014 radiological findings. J Craniomaxillofac Surg. 2007;35: 151-160. Reprint requests: Lei Liu Department of Oral and Maxillofacial Surgery West China Hospital of Stomatology Sichuan University Chengdu 610041 China [email protected]
