In the lateral part, the incision was extended without lateral canthotomy. The lateral canthal tendon was released as part of the subperiosteal undermining of the lateral orbital wall. The lateral orbital wall was degloved. In the first cadaver, no further degloving was executed through this incision. Osteotomies of the zygomaticofrontal junction were performed with the piezoelectric scalpel with a straight blade (Fig. 2B). Osteotomies of the medial orbital wall, the orbital floor, and the lateral orbital wall were performed with a 90° tip blade (Fig. 2C). In the second cadaver, a tunneled subperiosteal dissection of the orbital process of the malar bone of 1 cm of width formed the access to the anterior part of the zygomatic arch. The zygomatic osteotomy was performed with the piezotome with a 90° tip blade through this tunneled access and was endoscopically verified (Fig. 2D).
Single-Vertical Glabellar Incision
A short (8 mm) vertical incision was made on the midline of the glabellar region (Figs. 1 and 3A). A freer elevator was used to create a subperiosteal tunnel of the frontonasal bone surface and the medial orbital wall. The tip of the freer elevator must be visualized via the transconjunctival approach (Fig. 2A). Care must be taken to keep the medial canthal ligaments intact. The piezotome with a 15 mm straight blade was used for the nasofrontal osteotomy. The piezotome is directed toward the back of the nasal septum, while placing a finger behind the soft palate at the posterior spine. Only the first 1 cm of the nasal septum was cut by the piezotome. The septal osteotomy was completed with an 8 mm straight Bauer osteotome (Fig. 3B) under endoscopic guidance (Fig. 3C). The osteotomy of the medial orbital wall was performed through the vertical glabellar incision, while visualizing the tip of the piezotome via the transconjunctival approach.
In the first patient, the zygomatic osteotomy was performed via a 1.5 cm mucosal incision on each side. The mucosa was incised 1 cm above the gingivobuccal sulcus at the level of the first molar. A Molt periosteal elevator was used for a tunneled subperiosteal dissection of the maxillary process of the zygoma, the anterior part of the zygomatic arch, and the pterygomaxillary junction. The zygomatic osteotomy was performed with the piezotome with straight blade. An Obwegeser pterygoid osteotome was used to complete the pterygomaxillary osteotomy. In the second patient, the zygomatic osteotomy was performed through the transconjunctival approach. The bilateral pterygomaxillary osteotomy was performed by intraoral transmucosal placement of the Obwegeser pterygoid osteotome without subperiosteal dissection.
The Rowe maxillary disimpaction forceps were used to complete the Le Fort III osteotomy. The completeness of the osteotomy was verified manually, endoscopically, and radiographically by CT.
The minimally invasive Le Fort III osteotomy was successfully performed in both cadavers. The midface could be completely mobilized with the Rowe forceps. The endoscope proved its value in assisting the surgery, but more importantly, in verifying the completeness of the osteotomy. Computed tomography data could confirm this and showed no malpositioned osteotomy lines. Operative times of the minimally invasive Le Fort III osteotomy were 125 and 140 min.
By standardizing the Le Fort III osteotomy for the surgical treatment of many types of craniofacial abnormalities, Tessier5 promoted the coronal incision for the surgical exposure of the midface. The coronal incision provided an alternative approach for the visible scars in the region of the nasion, the zygomaticomaxillary suture, or the lateral canthus, which earlier the authors avocated.2–4 It provided a better exposure and more extensive deglovement to facilitate immediate per-operative advancement of the midface. Furthermore, a coronal incision led to a closer visual control of the displacement of the midface in the 3 planes and allowed straightforward seating of bone grafts. The introduction of distraction osteogenesis, however, made stabilizing bone grafts and extensive deglovement superfluous. This clearly affected the incidence of complications12,13 and the peri- and postoperative morbidity,14 but could also make us reconsider the coronal approach. Although this approach has been well established and validated, it can be time consuming and leaves a visible ear-to-ear scar. Nowadays, the demand for methods to further lower the comorbidity of the surgery is prominent. Reconsidering a combination of the minimal incisions of the earliest pioneers2–4 to move away from a coronal incision should therefore be considered.
Several recent attempts have been made to revive the spirit and ideas of the old masters. Hollier et al7 demonstrated a shorter operative time and a reduction in blood loss by using a combination of a medially extended upper blepharoplasty, a transconjunctival incision with lateral canthotomy, and an intraoral retromolar incision. Taylor et al8 added the value of the use of endoscopic visualisation and an ultrasonic scalpel.
The authors tried to overcome the drawbacks of the incisions of the earliest publications on midface surgery. These were mainly related to the localization of the smaller incisions in a visible area. However, none of the proposed alternative approaches have been popularized or considered in the standard protocol for the treatment of midface deficiency. The coronal approach remains the gold standard. This is due to remaining issues with the proposed alternative access incisions, as mentioned in the introduction. The achievement of this dissection study is that it repositioned and further limited the minimally invasive surgical access incisions to reduce the risk of incision-related complications (transconjunctival incision without lateral canthotomy) and to facilitate the surgical access to the nasofrontal osteotomy (glabellar incision).
Syndromic severe midface hypoplasia causes ocular proptosis and chronic corneal exposure. During midface surgery, care must be taken to avoid corneal trauma. Perioperative protection with a Frost suture is essential. Advocating a transconjunctival approach as an alternative approach in these syndromic patients can encounter opposition, as a transconjunctival approach implies a greater risk for perioperative corneal damage. However, the authors believe that the transconjunctival incision has the potential to be used as a protective measure to avoid corneal damage. As soon as the approach to the infraorbital rim and the retrocaruncular approach have been completed, the anterior edge of the conjunctival flap can be sutured to the upper lid margin (Fig. 4). The delicate cornea is, therefore, hydrated and protected by a vascularized mucosal flap. Furthermore, we have proven that a lateral canthotomy is redundant to acquire a sufficient surgical exposure. Lateral canthotomies are associated with a high rate of lower eyelid malposition. The need to perform a reattachment of the lateral canthus at the end of every Le Fort III complicates even more the aesthetic repositioning of the lower eyelid if a lateral canthotomy is executed. We have shown that a lateral canthotomy can be avoided without compromising the surgical field.
The authors consider the osteotomy of the nasal septum as one of the most hazardous osteotomies of the Le Fort III procedure. The associated craniosynostosis with oxycephaly limits the anteroposterior width of the anterior cranial base. A minimal error in determining the direction of the osteotomy could damage the anterior cranial base, resulting in cerebrospinal fluid leakage or a subgaleal hematoma. The surgeon must be able to direct the osteotome toward the back of the nasal septum, while placing his finger behind the soft palate at the posterior spine. The virtual line between the osteotome and the surgeon's finger will determine the osteotomy line. A lateral approach through a blepharoplasty incision7,8 does not allow the surgeon to align the osteotome and his finger. The glabellar incision, however, maintains the option to align the osteotome in a similar way as in the coronal approach. The progression of the osteotome along the nasal septum can be guided by an intranasally positioned endoscope (Fig. 3C). Another advantage of the vertical glabellar scar is that the vector of distraction of the midface is parallel to the scar. Similar to the concept of the Lange relaxed skin tension lines, this theoretically could lead to a better wound healing. On the contrary, the extended upper blepharoplasty scars are submitted to a perpendicular traction by the distraction device.
Two different approaches to the zygomatic arch osteotomy have been described in this article. Alongside the traditional intraoral approach, the feasibility of a transconjunctival access to the zygoma osteotomy was assessed. Use of the piezotome with a 90° tip blade is essential to overcome the limitation in surgical exposure. Although feasible, substantial traction has to be applied to the lower eyelid and lateral canthal region.
Therefore, we do not recommend the transconjunctival access and prefer to use the traditional intraoral approach for the zygomatic arch osteotomy.
This technique has been developed to make midfacial distraction osteogenesis possible in a patient in whom a coronal approach has a significant infection risk due to the presence of a prosthetic forehead and cranial vault reconstruction. The applicability of this technique for other patients is limited to distraction patients. A conventional Le Fort III advancement with bone grafting and rigid fixation is not feasible through this minimal invasive approach.
By popularizing the Le Fort III osteotomy for the treatment of severe midface hypoplasia, Tessier promoted the coronal approach for surgical exposure. Earlier authors had been using a combination of smaller incisions to acquire enough access to perform the different osteotomies. Tessier discarded this strategy because of the localization of the scars in visible facial zones and the need for a more extensive deglovement to allow intraoperative static advancement of the midface. The shift from static osteosynthesis and bonegrafting to distraction osteosynthesis, and the constant demand to further lower comorbidity, could make us reconsider the coronal incision however. Although still the golden standard, the coronal approach can be time-consuming and leaves an ear-to-ear scar. An alternative to the coronal approach is presented that combines a minimally visible 8 mm glabellar scar with an intraoral and a transconjunctival incision. The glabellar vertical midline incision is used to have an uncompromised access to the nasofrontal bone and the nasal septum. The bilateral transconjunctival incisions without lateral canthotomy and a bilateral 1.5 cm intraoral incision provide enough surgical exposure to perform an endoscopically assisted piezo-electric Le Fort III osteotomy. Based on the cadaveric setup described in this report, this minimally invasive Le Fort III approach has proven its feasibility and efficiency for clinical use.
The authors thank Yolanda Busto and Eduardo Goenaga from Osteoplac for the use of the instrumentarium and the VarioSurg3.
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Keywords:© 2017 by Mutaz B. Habal, MD.
Craniofacial abnormalities; endoscopic surgical procedures; Le Fort osteotomy; midface hypoplasia; minimal invasive surgical procedures