Comparison of three different approaches in treatment of mandibular condylar fractures – Our experience

ABSTRACT

Background:

The principal transfacial routes described to approach condylar process fractures are preauricular, retromandibular, high submandibular, and their various modifications. The selection of a specific surgical approach mainly depends on the level of condylar fracture, displacement/dislocation of the proximal segment and time elapsed from the date of trauma. Not too many studies proclaim a unanimous consensus on “gold standard” approaches for particular levels of fracture.

Aim:

This study was conducted with the aim to lay down guidelines for determining the ideal surgical approach for treating different condylar fractures based on different clinical situations.

Methodology:

This prospective study was conducted on 60 patients that underwent open reduction internal fixation of condylar fractures according to preset study design. Inclusion criteria were fracture displacement more than 10 degrees, dislocation, shortening of ramal height more than 2 mm. Patients having maxillofacial fractures other than mandible and condylar fractures in edentulous patients were excluded from this study.

Results:

The risk of facial nerve injury was more in endaural group and parotid fistula was more evident in retromandibular subparotid group but there was no statistical difference between the groups. The surgical scar was inconspicuous in all three groups. Excellent results were achieved in the other parameters such as mouth opening, range of motion, bite force, and occlusion with all the three approaches. Postoperative CT scan showed satisfactory anatomical reduction.

Conclusion:

This study concludes that the decision-making on the approach to be selected for any particular condylar fracture depends on the level of fracture, presence of fracture dislocation, and time elapsed from the date of trauma.

INTRODUCTION

Open reduction internal fixation (ORIF) of a fractured condyle returns the condylar process to its pre traumatic position, restoring skeletal continuity, re-establishing normal mandibular position, and bringing teeth into their proper relationship.[1] Open versus closed treatment of condylar fractures has been a long standing controversy, but recent meta-analysis and systematic reviews have proved ORIF to be better.[1–3]

The principal transfacial routes described to approach condylar process fractures are preauricular, retromandibular, high submandibular and their various modifications. Not too many studies proclaim a unanimous consensus on “gold standard” approaches for particular levels of fracture. Of these, the preauricular incision is suitable for the treatment of diacapitular and condylar neck fractures[4,5] but is rather unsuitable for of subcondylar fractures, wherein fixation becomes cumbersome, as screws cannot be oriented perpendicular to the plate.[6] The retromandibular approach is most commonly used for condylar neck and base fractures whereas high submandibular is a relatively newer approach for the same.[7]

The selection of a specific surgical approach mainly depends on the level of condylar fracture, displacement/dislocation of the proximal segment and additionally time elapsed from the date of trauma. Therefore, this study was designed to prove the efficiency of three approaches for different levels of condylar fractures-preauricular endaural for head fractures, retromandibular subparotid for neck fractures, and high submandibular for base fractures in specific clinical situations.

MATERIAL AND METHODS

This single centre, prospective, non-randomized, comparative study comprised a total number of 60 patients who underwent ORIF condylar fractures who came to the Department of Oral and Maxillofacial Surgery between June 2018 and December 2021. The study protocol was approved by the Institutional Ethical Committee vide no IEC GDCH/OS.2/2019 dated 10-04-2019.

Inclusion Criteria:[2]

• Age >18 years

• Unilateral or bilateral fractures with or without associated mandibular fractures having either:

  • Deranged occlusion and/or limitation of jaw movements.

  • Fracture displacement of more than 10 degrees of proximal segment with distal segment, with or without normal occlusion.

  • Fracture dislocation of condyle with or without normal occlusion.

  • Shortening of ramal height of more than 2 mm, associated with posterior premature contact.

• Medical contraindication of inter maxillary fixation.

Exclusion Criteria:

• Patient having associated maxillofacial fractures other than mandible, as results of occlusion may be biased

• Condylar fractures in edentulous patients, though operated were not included as occlusion could not be judged.

Methodology

Preoperative CT scans were performed to diagnose and evaluate the level, displacement and dislocation of condylar fractures. The condylar fractures were classified according to Luokota et al.[8]

60 consecutive patients with head, neck, and base condylar fractures undergoing ORIF were divided into three groups on the basis of the level of the fracture, fracture dislocation, and days elapsed from the date of trauma.

In the present study, early fracture was considered less than 2 weeks from the date of trauma and delayed fracture, beyond 2 weeks.

This study population were grouped as preauricular endaural (Group A), retromandibular subparotid (Group B), and high submandibular (Group C) approaches for head, neck, and base condylar fractures respectively. For fracture dislocations at any level, the approach used was one level higher, that is, retromandibular for a dislocated base fracture and preauricular for a dislocated neck fracture. For a delayed, malunited, dislocated fracture of condylar process at any level, the approach selected was endaural to check if condyle seats back in the glenoid fossa; in lower level fractures, if fixation was not possible with endaural approach, an additional high submandibular approach was used for fixation. This study design is described in Figure 1.

Figure 1.

Algorithm for approaches to condylar fractures

Surgical procedure

Endaural [Figure 2]

Figure 2.

(a) Endaural incision, (b) Exposure of fracture segment, (c) 6 months follow-up, (d) Preop coronal view showing bilateral condylar head fracture, (e) Postop coronal view showing bilateral transosseous wire fixation, (f) Preop 3D reconstruction, (g) Postop 3D reconstruction

Incision was given just at the junction of the helix with the preauricular skin, superiorly to inferiorly along the length of external ear passing over the tragus. Incision was made to the depth of the superficial layer of the temporalis fascia.

At the base of the zygomatic arch, a 45-degree incision through the superficial temporalis fascia in a superoanterior direction aiming 2 cm above and lateral to lateral canthus exposed the temporal fat pad. Dissecting in that plane permitted sub-periosteal dissection along zygomatic arch to expose the articular eminence while protecting the temporal branch of the facial nerve.

The capsule of the joint was then exposed and opened with a vertical incision along posterior border of the condyle to the disc and the fracture was then exposed.

Retromandibular subparotid [Figure 3]

Figure 3.

(a) Marking of retromandibular incision (2.5 cm), (b) Fixation of fracture with 3D delta plate, (c) 6 months follow-up, (d) Preop coronal view showing dislocated condylar base fracture on right side, (e) Post op coronal view, (f) Preop 3D reconstruction, (g) Postop 3D reconstruction

A 2.5 cm incision through the skin and subcutaneous tissue was placed 0.5 cm below attachment of the ear lobe just behind the posterior border of the ramus. Extensive undermining was done in the supraplatysmal plane anteriorly short of the facial artery and superiorly up to the zygomatic arch and inferiorly up to the lower border of the mandible, to allow ease of retraction.

The scant platysma, SMAS, and parotid capsule together were incised sharply parallel to the posterior border of the mandible. The tail of the parotid was then identified, lifted off masseter muscle and retracted superiorly. The substance of the parotid gland was not entered. At this level generally buccal and/or marginal mandibular branches of facial nerve are visible. Both branches were retracted and a sharp artery forceps was then inserted into the masseter.

Upon touching bone, artery forceps was opened along the long axis of the masseter. Subperiosteal dissection was done and fracture site exposed, without the need to incise the masseter.

High submandibular [Figure 4]

Figure 4.

(a) Marking of high submandibular incision (2 cm), (b) Fixation of fracture with 3D delta plate, (c) 6 months follow-up, (d) Preop coronal view showing right displaced condylar base fracture and left dislocated condylar base fracture, (e) Postop coronal view, (f) Preop 3D reconstruction, (g) Postop 3D reconstruction

A 2 cm skin incision was made anterior to the mandibular angle just below the lower border. A supraplatysmal subcutaneous dissection was performed for 2-3 cms. Then the platysma was cut obliquely toward ear lobe, exposing the underlying masseter muscle.

The superficial fascia covering the masseter houses a branch of facial nerve (usually buccal), which was isolated, dissected free, and retracted. Then a sharp artery forceps was introduced into the masseter and the fracture site exposed as in retromandibular subparotid approach.

Fixation

All the condylar neck and base fractures were fixed with 4-hole 2 mm 3D delta plate system and four, 2*6 mm titanium screws. Head fractures were fixed with single miniplate/lag screws/wires, depending on the size of the condylar head.

Parameters for evaluation

Subjects were evaluated preoperatively, intraoperatively, and postoperatively at 1 week, 1 month, and 6 months: Duration of surgery from the time of incision to the time of complete exposure of fracture segments (in mins) and time taken for fixation of fracture were recorded. Pain-Visual Analogue Scale (VAS), excursive movements (in mm), maximum interincisal opening (MIO), status of occlusion were also evaluated. Bite force was measured posteriorly at right and left 1^st molar and anteriorly at central incisors with gnathodynamometer. Postoperative anatomical reduction was checked on CT. Postoperative complications such as infection, parotid fistula, and facial nerve deficit were noted.

OBSERVATIONS AND RESULTS

60 patients (70% male and 30% female) with 74 condylar fractures were operated and followed up for 6 months. The mean age of the patients was 29.83 years according to the Chi-square test, P values were 0.621 and 0.636 for gender and age, respectively, so all three groups were comparable in gender and age.

Out of a total of 74 fractures, 18 were head fractures (24.32%), 16 neck fractures (21.62%), and 40 were base fractures (54.06%). Unilateral fractures were in 46 (76.67%) and bilateral condylar fractures were in 14 (23.33%) patients.

Mean time elapsed from date of trauma to time of surgery for Group A was 21.3 days, Group B was 9.9 days, and Group C was 8.3 days. However, this difference was because of 6 delayed fractures in Group A. When these delayed fractures were excluded, the results were statistically insignificant (p value-0.2365), hence making the time elapsed after trauma comparable in all 3 groups.

18 head fractures were approached through endaural incision, 14 out of 16 neck fractures were approached through the retromandibular subparotid incision. The remaining 2 neck fractures were approached through endaural incision as they were dislocated fractures. 22 out of 40 base fractures were approached through high submandibular incision, 12 base fractures were approached through retromandibular incision as there was fracture dislocation. Remaining 6 delayed dislocated base fractures of condyle were approached through endaural incision out of which 4 required additional high submandibular incision for fixation. So, for total 74 fractures, 78 incisions were used.

The mean time taken from incision to exposure of fracture in Group A, Group B, and Group C was 12.6 ± 0.96, 10.1 ± 1.7, and 5.9 ± 0.73 minutes and fixation time was 11.9 ± 1.9, 8.4 ± 1.4, and 6.4 ± 1.4, respectively. Comparison of the time taken from incision to exposure and fixation between the three groups was statistically significant (p value-0.0001 and 0.0001, respectively).

Fixation of all the 56 base and neck fractures was done with 3D delta titanium plates of the same company, while head fractures were fixed with transosseous wiring in 4, a single lag screw in 4 and a single miniplate in 10 instances.

Intergroup mouth opening and lateral excursion away from the fracture side was statistically insignificant preoperatively, postoperatively at 1 week, 1 month, and 6 months [Figure 5 and Table 1].

Figure 5.

Bar graph showing intergroup comparison of VAS, mouth opening, and lateral excursion

Table 1.

Mean, standard deviation, and P value for VAS, mouth opening, and lateral excursion at preoperatively, 1 week, 1 month, and 6 months postoperatively

VAS	Group A		Group B		Group C		P
	Mean	SD	Mean	SD	Mean	SD
Pre-op	7.60	1.17	8.10	0.74	8.30	0.67	0.2128
1 week	3.20	0.79	3.30	0.67	3.30	0.82	0.9447
1 month	0.20	0.42	0.20	0.42	0.20	0.42	>0.9999
6 months	0.00		0.00		0.00		>0.05
Mouth Opening	Mean	SD	Mean	SD	Mean	SD	P
Pre-op	18.00	3.61	18.50	2.59	19.00	1.88	0.9221
1 week	25.60	2.75	26.80	1.61	27.10	1.44	0.2339
1 month	34.80	2.25	35.10	1.10	36.40	1.95	0.2075
6 months	38.60	2.01	39.90	1.37	40.40	1.17	0.732
Lateral Excursion (mm)	Mean	SD	Mean	SD	Mean	SD	P
Pre-op	1.77	1.24	1.69	1.49	1.69	1.32	0.9893
1 week	5.0	0.71	5.08	1.04	5.0	1.0	0.9774
1 month	7.31	0.75	7.46	1.13	7.92	0.95	0.3423
6 months	9.69	0.63	9.62	0.51	9.46	0.52	0.6477

VAS-Visual Analogue Scale, mm-milimeter, SD-Standard deviation

Intergroup and intragroup bite force comparison at 1^st molar for left and right side at 6 months postoperatively was statistically insignificant (p value-0.6453 and 0.4079, respectively). All the fractures on postoperative CT scan were found to be reduced in complete anatomical position.

Postoperative occlusal discrepancy was present in four patients of Group A and two patients of Group B which was statistically insignificant (p value-0.3292).

Post operatively infection was absent in all patients of all groups. Parotid fistula was present in 2 patients of Group B postoperatively which was statistically insignificant (p value-0.5850).

Pain was statistically insignificant between the three groups preoperatively (p value-0.2128), postoperatively at 1 week (p value-0.9447), 1 month (0.999). At 6 months postoperatively, no patient complained of pain.

Transient facial nerve injury was present postoperatively in four patients of Group A, which was statistically insignificant (p value-0.3550).

DISCUSSION

Fractures of the condylar process are common maxillofacial injuries accounting for 25-52% of all mandibular fractures.[9,10] Treatment of condylar fractures is challenging, because fractures are difficult to access, bone fragments are small and difficult to align anatomically, and hardware placement is challenging.

In this study, the approaches to the condylar fracture were predecided based on level of fracture, presence of dislocation, time elapsed since trauma. The endaural incision provides excellent access to the lateral anterior and posterior aspect of the condylar head. It has a better esthetic value than the conventional preauricular approach.[11]

The standard retromandibular incision as described by Ed Ellis III measures 3-3.5 cm.[12] The incision used in this study the retromandibular subparotid was almost one centimeter smaller, therefore more conservative and tissue sparing. This approach had no incidence of facial nerve palsy, the least reported in the literature.

In their study of 469 high submandibular approaches, A. Louvrier et al.[13] used 4 cm long incision whereas in present study, only a 2 cm incision was used. Also, strict subcutaneous supraplatysmal dissection and then retracting the facial nerve branches found below the platysma prevented the facial nerve injury and led to a zero incidence of nerve injury again.

The average time taken from incision to exposure of surgical site and fixation in this study was the least for the high submandibular approach. This does not indicate that this incision is a faster or better incision. It just proves that as the level of fracture goes up, the level of difficulty of exposure and fixation increases; and so does the time taken for exposure and fixation.

Total time taken for high submandibular incision by A. Louvrier et al.[13] from incision to closure was 40 minutes. Retromandibular anteroparotid by Narayanan et al.[6] took 46 minutes. This time frame includes exposure, reduction, and fixation. In this study, the time taken from incision to exposure and time taken for fixation were given more importance as the time taken to reduce the fracture could vary on the basis of degree of displacement. Even so, the total mean time taken for high submandibular and retromandibular were 36 and 42 minutes, respectively, both less than the aforementioned studies, despite the fact that the incisions in this study were smaller than those mentioned above.

Preoperatively, the pain was obviously due to fresh trauma to the maxillofacial region. Post operatively, the pain significantly reduced to zero in all three groups at 6 months which was similar to Eckelt et al. 2006.[14]

According to Okeson, excursive movements less than 8 mm are considered to be restricted. Excursive movement away from the fracture side at 6 months for all the patients was more than 8 mm, signifying that all the three approaches provided adequate and stable fixation and function.

In this study, as there were delayed cases in Group A, intergroup statistical analysis for bite force was done at 6 months follow-up only. The bite force at 6 months did not depend on the level of fracture, or fractured and nonfractured side, which correlates with the bite force study in condylar fractures done by Ed Ellis and Thockmorton.[15] The bite force improved significantly from the preop values to 6 months in all the three groups which signifies that all the three approaches had good clinical outcomes.

Mean mouth opening gradually increased to 38.60 mm in Group A, 39.90 mm in Group B, and 40.40 mm in Group C at 6 months follow-up. This is due to resolution of factors interfering with the mouth opening such as pain and hematoma as also due to active physiotherapy adopted by the patients following good reduction and stable fixation. Findings of this study are similar to Li Z.[16]

In this study, preoperatively deviation on mouth opening was present only in four patients of Group A, all of which were delayed fractures. Postoperatively at 1 week, deviation on mouth opening was persistent in all these patients. This could be because of the muscle imbalance which was managed by guiding elastics for 2 weeks. None of these patients had deviation on mouth opening upon further follow-up. Chossegros et al.[17] also reported deviation on mouth opening in two patients out of 19 (11%).

Post operatively, occlusion was deranged in four (20%) patients of Group A and in two (10%) patients of Group B at first week, which was managed by guiding elastics for 2 weeks. Devlin et al.[18] who reported 2 out of 42 (23%) cases of occlusal derangement.

In this study, infection did not occur in any group. Hou et al.[19] and Li et al.[16] also did not report any cases of infection in their study.

Parotid fistula in two patients of Group B was managed successfully with pressure dressing and Tab Glycopyrrolate (antisialogogue) 5 mg twice a day for 1 week. No such complaints were noted in Groups A and C. Hou et al.[19] reported the same in 2 (6.67%) cases out of 30 patients treated with retromandibular approach.

At 1 week, 1 month and 6 months, scars were visible but thin and linear in all the patients. Devlin et al. 2002[18] reported a hypertrophic scar in one patient out of 42 (2.3%).

Transient facial nerve weakness in four patients of Group A resolved within 1 month in two patients and in 6 months in the other 2. Croce et al.,[20] reported 27% occurrence of a temporary paresis of facial nerve using the transparotid retromandibular approach. Ellis et al.,[21] observed this complication in 17.2% of his patients, with return of function spontaneously in 3 months. Tang et al. and Hammer et al.[22] reported damage to facial nerve after preauricular incision ranging from 3.2% to 42.9%.

CONCLUSION

Based on our experience, this study evaluated the endaural, retromandibular subparotid, and high submandibular approaches for head, neck, and base fractures of the condyle as described in the study design Figure 1.

The risk of facial nerve injury was more in endaural group and parotid fistula was more evident in retromandibular subparotid group but there was no statistical difference between the groups. The surgical scar was inconspicuous in all three groups. With the use of precise incisions for particular fracture types the amount of facial nerve palsy could be reduced to 5.1% in this study along with reduction in other complications such as infection, parotid fistula, and occlusal derangement. Excellent results were achieved in the other parameters such as mouth opening, range of motion, bite force, and occlusion with all the three approaches.

Thus, the authors hereby propose Figure 1 as the guidelines for surgical approaches to condylar fractures in terms of level of fracture, presence of fracture dislocation, and time elapsed from the date of trauma. Condylar fractures treated following these recommendations lead to excellent results in terms of appropriate and expeditious exposure of the fracture site, best anatomic reduction, and stable fixation.

Declaration of patient consent

The authors declare that they have obtained consent from patients. Patients have given their consent for their images and other clinical information to be reported in the journal. Patients understand that their names will not be published and due efforts will be made to conceal their identity but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.