- Email: [email protected]
Response to Drs Robiony and Sembronio
LETTER TO THE EDITOR J Oral Maxillofac Surg -:1-2, 2016
RESPONSE TO DRS ROBIONY AND SEMBRONIO In reply:—We appreciate Drs Robiony and Sembronio for their comments concerning our recent article ‘A modified preauricular approach for treating intracapsular condylar fractures to prevent facial nerve injury: The supratemporalis approach.’’1 We are glad that there are some similar views between those of Politi et al2 and ours in the surgical approach preventing facial nerve injury. However, it should be noted that several major differences between these 2 different modified preauricular approaches occur and are outlined herein. First, the shape and length of both the approaches are different. Our vertical leg was made anterior to the tragus and descended to stop at the earlobe, as shown in Figure 1A of our article,1 unlike the vertical part of the skin incision in the approach of Politi et al,2 extending just to the lower portion of the tragus, as shown in Figure 1 of their article, the location of which is much higher. The existence of this difference is due to the different indications of these 2 surgical approaches. The deep subfascial approach of Politi et al is mainly for temporomandibular joint (TMJ) ankylosis, TMJ arthrosis, mandibular hyperplasia, ossifying fibroma, etc., and the surgical procedures for these TMJ diseases mainly included a condylar shave, condylectomy, and arthroplasty. However, our approach is mainly for complex intracapsular condylar fractures that involved surgical treatment. Compared with the deep subfascial approach adopted by Politi et al, a greater exposure of the surgical field was required in our approach. Most of our surgical field arrived inferiorly at the sigmoid notch and condylar base, and some even extended anteriorly to the mandibular coronoid process, when the surgical procedure involved TMJ reconstruction with coronoid process graft. Second, the specific location of the modified incision in the plane of the deep temporalis fascia and the flaps of these 2 surgical approaches are quite different. In the deep subfascial approach of Politi et al,2 the incision was deepened into the areolar fat tissue and blunt dissection was carried out downward. Then, the first flap was produced, including the skin, the subcutaneous tissue, the superficial temporalis fascia, and the areolar fat tissue. At a level 2 cm above the malar arch, the modified incision of the upper and lower layers of the deep temporalis fascia was made, as shown in Figures 2 and 3 of the article of Politi et al, and then the second flap was produced, including the upper and lower layers of the deep temporalis fascia and the superficial temporal fat pad. However, in our technique, the skin incision was deepened into the superficial temporalis fascia, and the location of the modified incision that carried through the deep temporalis fascia was just below the skin incision, approximately at a level 3 to 5 cm above the zygomatic arch, exposing the temporal muscle, as shown in Figure 1B-D in our article.1 Then, a flap that included skin, subcutaneous tissue, the superficial temporal fascia, the areolar fat tissue, the deep temporalis fascia, and the superficial temporal fat pad was reflected as a whole anterior to the ear. Thus, no matter how variable the course of the temporal and zygomatic branch of the facial nerve is in the zygomaticotemporal region, it is enwrapped within this entire flap and can be well protected with the supratemporalis approach. Moreover, injury to the facial nerve is prevented, which can be confirmed from our clinical experience. Therefore, these 2 surgical approaches are different.
The second question we want to discuss is about the distributions of the facial nerve in the zygomaticotemporal region. In most cases, the temporal branches of the facial nerve run in the undersurface of the superficial temporalis fascia. This is the exact reason injury to the facial nerve does not occur with the traditional preauricular approach in most situations. However, both previous research3-5 and our clinical experience confirm that the incidence of anatomic variation of the facial nerve is not small. An aberrant temporal branch of the facial nerve may run in the undersurface of the deep temporalis fascia or within the superficial temporal fat pad, as shown in Figure 2 of our article.1 This anatomic variation can result in injury to the facial nerve during the dissection in the traditional approach. In fact, the anatomic variation of the facial nerve also is supported by Politi et al,2 stating ‘‘The risk of significant temporal branch injury has been attributed to the finding that it is significantly more superficial than the remaining branches of the facial nerve anterior to the parotid edge, to the dense fusion of the deep fascial layers as the nerve crosses over the zygomatic arch,’’ and confirmed in Figure 6 of their article. What our Figure 2 shows is exactly this anatomic variation of the facial nerve, and detailed explanation can be seen in our article. This is our main reason to adopt the supratemporalis approach for treating intracapsular condylar fractures to prevent facial nerve injury. We also are delighted to address the third concern regarding the nomenclatural issue of the term ‘‘supratemporalis approach.’’ The traditional view is that the deep temporalis fascia is split into 2 layers approximately 2 to 3 cm above the zygomatic arch. We feel obliged to point out that this is not exactly true. Until now, we have carried out more than 200 operations in patients with zygomaticofacial fractures and thus have been familiar with the anatomic structures in the temporal region. Among these surgical procedures, we did find that this so-called deep layer of the deep temporalis fascia did not exist. In fact, the superficial temporal fat pad is closely attached to temporal muscle above the zygomatic arch. The deep temporalis fascia is not separated into 2 layers; instead, it is only a single layer above the zygomatic arch. Cranial to the superotemporal line, it is in continuity with the pericranium. Continuing inferiorly to the zygomatic arch, it lies on the surface of the temporal muscle and the superficial temporal fat pad successively. In the supratemporalis approach, the surgical dissection plane over the point 3 to 4 cm above the zygomatic arch lies between the temporal muscle and the deep temporalis fascia, which below the point 3 to 4 cm above the zygomatic arch lies between the temporal muscle and the superficial temporal fat pad. To avoid the confusion of our modified dissection plane, the term ‘‘supratemporalis approach’’ emphasizes the precise dissection tissue plane, which is above the temporalis. This is the key reason for the nomenclature of this technique, called the ‘‘supratemporalis approach.’’ Finally, although there are some similarities between these 2 modified preauricular approaches, they are indeed different surgical techniques, as stated earlier. We thank Drs Robiony and Sembronio again for their comments and are willing to have more communication in the field of oral and maxillofacial surgery.
1
2
LETTER TO THE EDITOR HUI LI, DMD LEI LIU, PHD, MD Chengdu, China
References 1. Li H, Zhang G, Cui J, et al: A modified preauricular approach for treating intracapsular condylar fractures to prevent facial nerve injury: The supratemporalis approach. J Oral Maxillofac Surg 74:1013, 2016 2. Politi M, Toro C, Cian R, et al: The deep subfascial approach to the temporomandibular joint. J Oral Maxillofac Surg 62:1097, 2004
3. Ammirati M, Spallone A, Ma J, et al: An anatomicosurgical study of the temporal branch of the facial nerve. Neurosurgery 33:1038, 1993 4. Coscarella E, Vishteh AG, Spetzler RF, et al: Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontalis branch of the facial nerve: Technical note. J Neurosurg 92:877, 2000 5. Gosain AK, Sewall SR, Yousif NJ: The temporal branch of the facial nerve: How reliably can we predict its path? Plast Reconstr Surg 99:1224, 1997
http://dx.doi.org/10.1016/j.joms.2016.07.028
RESPONSE TO DRS ROBIONY AND SEMBRONIO In reply:—We appreciate Drs Robiony and Sembronio for their comments concerning our recent article ‘A modified preauricular approach for treating intracapsular condylar fractures to prevent facial nerve injury: The supratemporalis approach.’’1 We are glad that there are some similar views between those of Politi et al2 and ours in the surgical approach preventing facial nerve injury. However, it should be noted that several major differences between these 2 different modified preauricular approaches occur and are outlined herein. First, the shape and length of both the approaches are different. Our vertical leg was made anterior to the tragus and descended to stop at the earlobe, as shown in Figure 1A of our article,1 unlike the vertical part of the skin incision in the approach of Politi et al,2 extending just to the lower portion of the tragus, as shown in Figure 1 of their article, the location of which is much higher. The existence of this difference is due to the different indications of these 2 surgical approaches. The deep subfascial approach of Politi et al is mainly for temporomandibular joint (TMJ) ankylosis, TMJ arthrosis, mandibular hyperplasia, ossifying fibroma, etc., and the surgical procedures for these TMJ diseases mainly included a condylar shave, condylectomy, and arthroplasty. However, our approach is mainly for complex intracapsular condylar fractures that involved surgical treatment. Compared with the deep subfascial approach adopted by Politi et al, a greater exposure of the surgical field was required in our approach. Most of our surgical field arrived inferiorly at the sigmoid notch and condylar base, and some even extended anteriorly to the mandibular coronoid process, when the surgical procedure involved TMJ reconstruction with coronoid process graft. Second, the specific location of the modified incision in the plane of the deep temporalis fascia and the flaps of these 2 surgical approaches are quite different. In the deep subfascial approach of Politi et al,2 the incision was deepened into the areolar fat tissue and blunt dissection was carried out downward. Then, the first flap was produced, including the skin, the subcutaneous tissue, the superficial temporalis fascia, and the areolar fat tissue. At a level 2 cm above the malar arch, the modified incision of the upper and lower layers of the deep temporalis fascia was made, as shown in Figures 2 and 3 of the article of Politi et al, and then the second flap was produced, including the upper and lower layers of the deep temporalis fascia and the superficial temporal fat pad. However, in our technique, the skin incision was deepened into the superficial temporalis fascia, and the location of the modified incision that carried through the deep temporalis fascia was just below the skin incision, approximately at a level 3 to 5 cm above the zygomatic arch, exposing the temporal muscle, as shown in Figure 1B-D in our article.1 Then, a flap that included skin, subcutaneous tissue, the superficial temporal fascia, the areolar fat tissue, the deep temporalis fascia, and the superficial temporal fat pad was reflected as a whole anterior to the ear. Thus, no matter how variable the course of the temporal and zygomatic branch of the facial nerve is in the zygomaticotemporal region, it is enwrapped within this entire flap and can be well protected with the supratemporalis approach. Moreover, injury to the facial nerve is prevented, which can be confirmed from our clinical experience. Therefore, these 2 surgical approaches are different.
The second question we want to discuss is about the distributions of the facial nerve in the zygomaticotemporal region. In most cases, the temporal branches of the facial nerve run in the undersurface of the superficial temporalis fascia. This is the exact reason injury to the facial nerve does not occur with the traditional preauricular approach in most situations. However, both previous research3-5 and our clinical experience confirm that the incidence of anatomic variation of the facial nerve is not small. An aberrant temporal branch of the facial nerve may run in the undersurface of the deep temporalis fascia or within the superficial temporal fat pad, as shown in Figure 2 of our article.1 This anatomic variation can result in injury to the facial nerve during the dissection in the traditional approach. In fact, the anatomic variation of the facial nerve also is supported by Politi et al,2 stating ‘‘The risk of significant temporal branch injury has been attributed to the finding that it is significantly more superficial than the remaining branches of the facial nerve anterior to the parotid edge, to the dense fusion of the deep fascial layers as the nerve crosses over the zygomatic arch,’’ and confirmed in Figure 6 of their article. What our Figure 2 shows is exactly this anatomic variation of the facial nerve, and detailed explanation can be seen in our article. This is our main reason to adopt the supratemporalis approach for treating intracapsular condylar fractures to prevent facial nerve injury. We also are delighted to address the third concern regarding the nomenclatural issue of the term ‘‘supratemporalis approach.’’ The traditional view is that the deep temporalis fascia is split into 2 layers approximately 2 to 3 cm above the zygomatic arch. We feel obliged to point out that this is not exactly true. Until now, we have carried out more than 200 operations in patients with zygomaticofacial fractures and thus have been familiar with the anatomic structures in the temporal region. Among these surgical procedures, we did find that this so-called deep layer of the deep temporalis fascia did not exist. In fact, the superficial temporal fat pad is closely attached to temporal muscle above the zygomatic arch. The deep temporalis fascia is not separated into 2 layers; instead, it is only a single layer above the zygomatic arch. Cranial to the superotemporal line, it is in continuity with the pericranium. Continuing inferiorly to the zygomatic arch, it lies on the surface of the temporal muscle and the superficial temporal fat pad successively. In the supratemporalis approach, the surgical dissection plane over the point 3 to 4 cm above the zygomatic arch lies between the temporal muscle and the deep temporalis fascia, which below the point 3 to 4 cm above the zygomatic arch lies between the temporal muscle and the superficial temporal fat pad. To avoid the confusion of our modified dissection plane, the term ‘‘supratemporalis approach’’ emphasizes the precise dissection tissue plane, which is above the temporalis. This is the key reason for the nomenclature of this technique, called the ‘‘supratemporalis approach.’’ Finally, although there are some similarities between these 2 modified preauricular approaches, they are indeed different surgical techniques, as stated earlier. We thank Drs Robiony and Sembronio again for their comments and are willing to have more communication in the field of oral and maxillofacial surgery.
1
2
LETTER TO THE EDITOR HUI LI, DMD LEI LIU, PHD, MD Chengdu, China
References 1. Li H, Zhang G, Cui J, et al: A modified preauricular approach for treating intracapsular condylar fractures to prevent facial nerve injury: The supratemporalis approach. J Oral Maxillofac Surg 74:1013, 2016 2. Politi M, Toro C, Cian R, et al: The deep subfascial approach to the temporomandibular joint. J Oral Maxillofac Surg 62:1097, 2004
3. Ammirati M, Spallone A, Ma J, et al: An anatomicosurgical study of the temporal branch of the facial nerve. Neurosurgery 33:1038, 1993 4. Coscarella E, Vishteh AG, Spetzler RF, et al: Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontalis branch of the facial nerve: Technical note. J Neurosurg 92:877, 2000 5. Gosain AK, Sewall SR, Yousif NJ: The temporal branch of the facial nerve: How reliably can we predict its path? Plast Reconstr Surg 99:1224, 1997
http://dx.doi.org/10.1016/j.joms.2016.07.028