The dot shows outlier cadaver 3. Boxes represent interquartile range. Bars represent minimum and maximum values.
The dots show outlier cadavers 3 and 4. Boxes represent interquartile range. Bars represent minimum and maximum values.
Moubayed SP, Labbé D, Rahal A. Lengthening Temporalis Myoplasty for Facial Paralysis ReanimationAn Objective Analysis of Each Surgical Step. JAMA Facial Plast Surg. 2015;17(3):179-182. doi:10.1001/jamafacial.2015.46
Lengthening temporalis myoplasty is a dynamic procedure used to reanimate the middle third of the paralyzed face. Since its original description, it has been progressively modified over the years, with a reduction in the number of surgical steps. However, these modifications can decrease lengthening needed for the tendon to reach the oral commissure and upper lip without tension or overcorrection.
To evaluate the maximal lengthening of the temporalis tendon that is possible with this technique and to assess the contribution of each surgical step to total lengthening.
Design, Setting, and Participants
Cadaveric dissection study from September 16 to 23, 2013, at a tertiary referral center using 10 cadaveric hemifaces.
Main Outcomes and Measures
Surgical exposure was obtained using coronal and melolabial incisions. The original surgical technique was broken down into 7 steps. Measurement of temporalis tendon lengthening relative to a fixed point was performed by a single surgeon after each surgical step using a millimeter ruler.
Each surgical step resulted in progressive temporalis tendon lengthening for a median maximal total lengthening of 43.5 mm. The steps that contributed most to this lengthening were coronoidotomy and intraoral temporalis tendon dissection (median, 12.0 mm), incision of temporalis fascia insertion over the orbital rim (median, 6.5 mm), and zygomatic osteotomy with dissection of masseteric fibers (median, 11.5 mm), which represent the first and last 2 steps of the procedure, respectively.
Conclusions and Relevance
Modifications of lengthening temporalis myoplasty must be considered with caution because the maximal lengthening potential can be obtained only when performing all 7 surgical steps. These modifications must be chosen appropriately based on the lengthening required for the temporalis tendon to reach the oral commissure and upper lip without tension or overcorrection.
Level of Evidence
Rehabilitation of the paralyzed face is especially important to the patient with chronic facial paralysis. Several methods have been described to restore the static and dynamic symmetry of the middle third of the face. Lengthening temporalis myoplasty (LTM), originally described in 1997 by Labbé,1 consists of a regional muscle and tendon transfer in which the temporalis tendon is transferred from its attachment on the coronoid process to the oral commissure after complete mobilization of the temporalis muscle through a coronal approach and zygomatic arch osteotomy.1 We believe that the temporalis tendon needs to be reattached directly (without any graft or fascia) to the oral commissure and upper lip without any tension or overcorrection to achieve an optimal result. This requires mobilization of the temporalis muscle to be lengthened to the appropriate level. Lengthening required to achieve that goal was initially clinically measured as approximately 4 cm.1 The original technique was subsequently modified by Labbé2 in 2009 (LTM version 2) and consisted of detaching only the posterior half of the temporalis fascia but dissecting the whole muscle from its fossa and avoiding zygomatic osteotomy. Boahene et al3 proposed detaching the temporalis tendon from the coronoid process and avoiding temporalis muscle dissection altogether. This procedure was called temporalis tendon transfer. All these procedures are different variations of orthodromic temporalis myoplasty without an extension graft. To date, the lengthening potential of these progressive modifications has not been evaluated. We hypothesize that modification of the original LTM technique might result in a decreased lengthening potential. Therefore, we conducted a cadaveric dissection study to evaluate the maximal lengthening possible with LTM and to assess the contribution of each surgical step to total temporalis tendon lengthening.
A cadaveric dissection study using 10 fresh cadaveric hemifaces was conducted from September 16 to 23, 2013. The institutional review board at Maisonneuve-Rosemont Hospital (Montreal, Quebec, Canada) approved the study. Surgical exposure was obtained using coronal and melolabial incisions in all cadaveric heads.
We started with the melolabial approach and exposure of the coronoid process and temporalis tendon. A hole was then drilled though the distal part of the coronoid process, and a 2-0 polypropylene suture was passed through the hole and then firmly tied to the coronoid process before coronoidotomy. A Kocher clamp was placed at the end of the suture at the level of the melolabial fold. This process defined our zero starting point. After each surgical step, the same surgeon (A.R.) exerted uniform tension on the Kocher clamp until resistance was felt. The distance from the Kocher clamp to the melolabial fold was measured by the same surgeon using a millimeter ruler. This process defined our lengthening for each step.
The original surgical technique of LTM was described in 1997 by Labbé.1 Based on this technique and its subsequent modifications, we broke down the procedure into the following 7 steps for our measurements: (1) coronoid process osteotomy and intraoral temporalis tendon dissection (dissection of the temporalis tendon from all its attachments laterally from the masseter muscle and medially from the pterygoid muscles), (2) coronal approach and retrozygomatic dissection (dissection between the deep aspect of the zygomatic arch and the temporalis muscle), (3) incision of the posterior half of the temporalis fascia and dissection of only the posterior half of the temporalis muscle from the fossa, (4) dissection of the rest of the temporalis muscle from the fossa but leaving the anterior fascia attached to the temporal line, (5) incision of anterior temporalis fascia up to the orbital rim, (6) incision of temporalis fascia insertion over the orbital rim, and (7) zygomatic arch osteotomy, followed by dissection of residual masseteric fibers from the surface of the temporalis muscle. Total and relative lengthening after each step is reported in millimeters.
Total and relative lengthening for each cadaveric hemiface is summarized in Table 1. The cumulative and individual contributions of each surgical step to total temporalis tendon lengthening are summarized in Table 2, Figure 1, and Figure 2. Data are presented using medians and box and whisker plots because of nonnormal distributions.
The median maximal total lengthening measured in our study after completing all 7 steps of the original technique was 43.5 mm. This cadaveric finding confirms the lengthening potential clinically identified as approximately 40 mm in the initial description of the technique.1 Our results elucidate the importance of all 7 surgical steps to achieve the maximal temporalis tendon lengthening.
Three surgical steps contributed most to this lengthening. The first step, which is coronoidotomy and intraoral temporalis tendon dissection, produced the most lengthening (median, 12.0 mm). We believe that lengthening achieved with this step is mainly due to the anterior rotation of the tendon after having completed the coronoidotomy and the resultant sliding through the buccal space. This step cannot be avoided in any modification of orthodromic temporalis myoplasties because it is the basis of the full procedure. An essential part of this step is to completely skeletonize the temporalis muscle tendon by bluntly separating all the parasitic fibers of the medial pterygoid and the masseter muscles using a large periosteal elevator to allow it to slide anteriorly and inferiorly as much as possible.
The last step of the procedure (zygomatic osteotomy with dissection of masseteric fibers) produced a median lengthening of 11.5 mm. In a cadaveric study published in 2011, Guerreschi et al4 described fibers of the masseter muscle that pass up to the zygomatic arch and terminate on the deep surface of the temporalis fascia. Release of these parasitic fibers that belong to the deep masseter muscle seems to contribute greatly to lengthening of the tendon. Also, the zygomatic arch osteotomy facilitates dissection of the temporalis muscle lower down toward the lateral skull base. Dissection in this area should extend up to the sphenotemporal crests, and one should release the fascial insertion of the deep portion of the temporalis muscle around these crests at the level of the skull base.
Another important step was incision of temporalis fascia insertion over the orbital rim (step 6), which produced a median lengthening of 6.5 mm. This result is probably due to release of the most anterior temporalis muscle fibers along the lateral orbital rim.
The LTM version 2 modification described in 2009 by Labbé2 avoids anterior temporal fascia disinsertion and zygomatic osteotomy. When translated in terms of our surgical steps, this technique uses steps 1 to 4 only. Based on our results herein, the median maximal total lengthening possible using this technique is 23.0 mm. Compared with the maximal lengthening potential using all 7 steps, the loss of potential lengthening is 20.5 mm. The second modification by Boahene et al3 in 2011 avoided temporalis muscle dissection altogether and is based on coronoidotomy and intraoral temporalis tendon dissection (step 1) and on retrozygomatic dissection (step 2). Using our data herein, the modification could produce a median maximal total lengthening of 15.0 mm. This translates into a loss of 28.5 mm of potential lengthening compared with the original LTM procedure.
The relative lengthening achieved by each step is dependent on completion of the previous steps. Despite our use of a cadaveric model, our results demonstrate that orthodromic temporalis myoplasties are not equivalent in terms of the lengthening potential. Although extrapolation of our results in terms of facial symmetry at rest and facial dynamic restoration has not been studied to date, the surgeon performing temporalis myoplasty must remain aware that each surgical step contributes to the lengthening potential.
The sequence used in our study (steps 1 to 7) should guide the surgeon performing this procedure. He or she must always be ready to perform the steps required for the tendon to reach its point of attachment in the midface, with minimal tension or overcorrection, unless the surgeon wants to add an extension graft to the temporalis tendon (fascia lata or allograft).
However, a common feature of allografts and autografts in fascial suspension techniques is unpredictable stretching over time,5 as well as risk of infection or extrusion with allografts. For this reason, we prefer to not use any grafts between the tendon and commissure. When the tendon reaches the middle third of the face without tension or overcorrection, we believe that the static and dynamic symmetry is optimal and will be maintained over time.
With our current method, it is impossible to determine whether total lengthening was obtained from true lengthening, sliding, or stretching of the temporalis muscle tendon. Moreover, although this study analyzed the potential for temporalis tendon mobilization, it could not provide data on contractility of the muscle tendon unit given the cadaveric nature of the methods.
Based on our results, the median maximal total lengthening possible with LTM is 43.5 mm and requires all 7 steps to be completed. The steps that contributed most to tendon lengthening are coronoidotomy and intraoral temporalis tendon dissection (median, 12.0 mm), incision of temporalis fascia insertion over the orbital rim (median, 6.5 mm), and zygomatic osteotomy with dissection of masseteric fibers (median, 11.5 mm). Modifications of the original LTM procedure must be considered with caution because the maximal lengthening potential can be obtained only when performing all 7 surgical steps. The surgeon must always be ready to perform the steps that are required for the temporalis tendon to reach its point of attachment in the midface, with minimal tension or overcorrection, unless he or she wants to add an extension graft to the temporalis tendon (fascia lata or allograft).
Accepted for Publication: January 4, 2015.
Corresponding Author: Akram Rahal, MD, Otolaryngology–Head and Neck Surgery Service, Department of Surgery, Maisonneuve-Rosemont Hospital, 5415 Blvd de l’Assomption, Montréal, QB H1T 2M4, Canada (email@example.com).
Published Online: March 12, 2015. doi:10.1001/jamafacial.2015.46.
Author Contributions: Dr Moubayed had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: All authors.
Acquisition, analysis, or interpretation of data: Moubayed, Rahal.
Drafting of the manuscript: Moubayed, Rahal.
Critical revision of the manuscript for important intellectual content: Labbé, Rahal.
Conflict of Interest Disclosures: None reported.