Repositioning the orbicularis oculi muscle in the composite rhytidectomy.

While blepharoplasties are routinely done with face lift procedures, the improvement is accomplished by removing excess orbital fat with eyelid skin and muscle along the incisional line. The orbicularis oculi muscle remains intact as its inferior border, which has become ptotic and redundant with aging, and actually remains in the same position following a conventional lower lid blepharoplasty and rhytidectomy. However, by elevating the orbicularis oculi with the cheek fat and platysma in a composite face lift flap, and by excising the redundant inferior border of the orbicularis muscle, a total rejuvenation of the malar area is accomplished. The descent of the orbicularis oculi muscle is in an inferolateral vector, whereas the vector of facial aging is inferomedial. Thus, repositioning the orbicularis oculi is in a superomedial vector and is obligatory in a composite rhytidectomy.     

Composite rhytidectomy.

Signs of aging in the face reflect the change in position of deep anatomic elements, which are the platysma muscle, cheek fat, and the orbicularis oculi muscle. These changes occur from progressive ptosis of these elements, which continue to keep their intimate relationship with each other throughout the aging process. Conventional face lift procedures disrupt this normal relationship by separating the skin from these elements. All SMAS techniques reposition only the platysma muscle without repositioning the cheek fat and orbicularis muscle. This composite rhytidectomy allows elevation of a composite musculocutaneous flap containing all three elements for repositioning while maintaining their intimate relationship with each other and with the skin. One-hundred and sixty-seven composite rhytidectomies have been done with impressive results and minimal complications.     

Refinements in face lifting: enhanced facial contour using vicryl mesh incorporated into SMAS fixation

As we have gained experience with the extended superficial musculoaponeurotic system (SMAS) technique in face lifting, refinements in our procedure have led to increased consistency in results. The important factors that have led to our technical modifications include the following: (1) the significance of the retaining ligaments of the midface, which determine the degree of surgical dissection required for both skin and SMAS in rhytidectomy; (2) the changes in facial shape that occur with aging, secondary to the descent of facial fat; (3) the possibility of modifying facial shape through the repositioning of facial fat in an extended SMAS face lift; (4) the improved longevity of result to be obtained by incorporating Vicryl mesh into SMAS fixation; (5) the artistic nuances of incision design that help to minimize scar perceptibility. Understanding these factors enables surgeons to use the extended SMAS technique successfully with more challenging cases, enhancing facial appearance while minimizing signs that the patient has undergone a surgical procedure.     

Circumauricular incision (water-drop shape) for mid- to lower face lift

The conventional method of mid- to lower face rhytidectomy that involves removing a strip of occipital scalp always creates a conspicuous transverse scar crossing the postauricular skin, which may leave a stair-step deformity at the occipital hairline. The author has designed a new face lift method using a circumauricular incision, shaped like a water droplet, that curves around the auricle. In this new method, the upper part of the "O" shape is modified to the tip of a water droplet. The dissection of the cheek and neck is performed as in the conventional method with light-retractor assistance. The temporal region above the deep temporal fascia is managed under endoscopic control. This dissection can extend to the forehead region lateral to the supraoptic nerve and around the lateral orbital rim to release the arcus marginalis. A mesentery of superficial temporal fascia is created cephalic to the zygomatic arch. The postauricular dissection is performed beneath the galea in the upper part and beneath the occipital scalp and neck skin in the lower area. The lifting vector is upward and backward for the anterior skin flap and upward for the posterior skin flap. The excess skin is trimmed around the ear. The wound at the upper pole of the incision is closed in a V-to-Y advancement fashion. The dog-ear is left above the normal hairline, and there is little or no hairy scalp to be removed. The skin pleating in the postauricular region will settle down spontaneously after several months. The dog-ear in the scalp will become smaller and flat as well. The scar around the ear is quite inconspicuous and well covered under the upper pole of the auricle. From the author's experience, the new "water drop" circumauricular incision is a good alternative for the mid- to lower face lift. It can also be used in conjunction with endoforehead lift for full-face rejuvenation.     

Stretching and tissue expansion for rhytidectomy: an improved approach

Intraoperative expansion of the skin of the face supplies additional tissue that permits closure of the face lift incision with minimal tension. This paper presents the findings in rhytidectomy patients over the last 3 years using both intraoperative stretching and intraoperative stretching combined with tissue expansion utilizing the Man face lift expander. Sixty-seven patients underwent rhytidectomy surgery, of whom 50 were treated with stretching techniques alone and 17 were treated with the combined stretching and expansion method. The patients' ages ranged from 28 to 78 years. Results indicate that the patients treated with combined stretching and expansion had significantly more skin removed. This new technique appears to offer significant clinical advantages over usual face lifts.     

Biomechanical and viscoelastic properties of skin,SMAS, and composite flaps as they pertain to rhytidectomy

Previous studies have focused on biomechanical and viscoelastic properties of the superficial musculoaponeurotic system (SMAS) flap and the skin flap lifted in traditional rhytidectomy procedures. The authors compared these two layers with the composite rhytidectomy flap to explain their clinical observations that the composite dissection allows greater tension and lateral pull to be placed on the facial and cervical flaps, with less long-term stress-relaxation and tissue creep. Eight fresh cadavers were dissected by elevating flaps on one side of the face and neck as skin and SMAS flaps and on the other side as a standard composite rhytidectomy flap. The tissue samples were tested for breaking strength, tissue tearing force, stress-relaxation, and tissue creep. For breaking strength, uniform samples were pulled at a rate of 1 inch per minute, and the stress required to rupture the tissues was measured. Tissue tearing force was measured by attaching a 3-0 suture to the tissues and pulling at the same rate as that used for breaking strength. The force required to tear the suture out of the tissues was then measured. Stress-relaxation was assessed by tensing the uniformly sized strips of tissue to 80 percent of their breaking strength, and the amount of tissue relaxation was measured at 1-minute intervals for a total of 5 minutes. This measurement is expressed as the percentage of tissue relaxation per minute. Tissue creep was assessed by using a 3-0 suture and calibrated pressure gauge attached to the facial flaps. The constant tension applied to the flaps was 80 percent of the tissue tearing force. The distance crept was measured in millimeters after 2 and 3 minutes of constant tension. Breaking strength measurements demonstrated significantly greater breaking strength of skin and composite flaps as compared with SMAS flaps (p < 0.05). No significant difference was noted between skin and composite flaps. However, tissue tearing force demonstrated that the composite flaps were able to withstand a significantly greater force as compared with both skin and SMAS flaps (p < 0.05). Stress-relaxation analysis revealed the skin flaps to have the highest degree of stress-relaxation over each of five 1-minute intervals. In contrast, the SMAS and composite flaps demonstrated a significantly lower degree of stress-relaxation over the five 1-minute intervals (p < 0.05). There was no difference noted between the SMAS flaps and composite flaps with regard to stress-relaxation. Tissue creep correlated with the stress-relaxation data. The skin flaps demonstrated the greatest degree of tissue creep, which was significantly greater than that noted for the SMAS flaps or composite flaps (p < 0.05). Comparison of facial flaps with cervical flaps revealed that cervical skin, SMAS, and composite flaps tolerated significantly greater tissue tearing forces and demonstrated significantly greater tissue creep as compared with facial skin, SMAS, and composite flaps (p < 0.05). These biomechanical studies on facial and cervical rhytidectomy flaps indicate that the skin and composite flaps are substantially stronger than the SMAS flap, allowing significantly greater tension to be applied for repositioning of the flap and surrounding subcutaneous tissues. The authors confirmed that the SMAS layer exhibits significantly less stress-relaxation and creep as compared with the skin flap, a property that has led aesthetic surgeons to incorporate the SMAS into the face lift procedure. On the basis of the authors' findings in this study, it seems that that composite flap, although composed of both the skin and SMAS, acquires the viscoelastic properties of the SMAS layer, demonstrating significantly less stress-relaxation and tissue creep as compared with the skin flap. This finding may play a role in maintaining long-term results after rhytidectomy. In addition, it is noteworthy that the cervical flaps, despite their increased strength, demonstrate significantly greater tissue creep as compared with facial flaps, suggesting earlier relaxation of the neck as compared with the face after rhytidectomy.     

Intraoperative tissue expansion in rhytidectomy revisited

Intraoperative tissue expansion is an adjunct that has been used during rhytidectomy to rejuvenate the face and neck. This technique has been thought to allow for additional skin resection and, thus, increased skin tightening during rhytidectomy. The stretch of the skin by expansion should allow for additional skin resection before closure. Also, when the force of the underlying expander is removed, the expanded skin would recoil and the advancement of the flap should become tighter, with improved results. The technique achieved some popularity a few years ago but has received little recent attention. In this study, the authors attempted to compare face-lift results of adjunctive intraoperative tissue expansion during rhytidectomy with similar techniques without intraoperative expansion. The results of 50 female patients who underwent rhytidectomy for midface rejuvenation by a single operating surgeon composed the study group. Twenty-five of the patients had undergone rhytidectomy that addressed the cheek, chin, and neck areas without expansion (nonexpanded rhytidectomy group). The other 25 patients (expanded rhytidectomy group) had adjunctive intraoperative tissue expansion performed with the rhytidectomy. A tissue expander was temporarily placed beneath the rhytidectomy flaps on each side and expanded in a standard manner before final skin resection and closure. Frontal and lateral photographs were evaluated by 54 examiners. Preoperative and postoperative photographs of the 50 patients were viewed side-by-side by the examiners. The patients were presented in blind fashion and random order. The examiners graded the results of each patient on a scale of improvement from 1 to 10, with 10 being the maximum level of improvement. The scores were recorded and statistically evaluated by using the two-sample test. Evaluation of the examiners' scores showed that the mean rating given to patients in the expanded rhytidectomy group was 5.07 (SD = 1.12). The mean rating for the nonexpanded rhytidectomy group was 5.27 (SD = 1.57). When the two groups were compared using the two-sample test, the difference between the two was not statistically significant (p = 0.6127). Intraoperative tissue expansion as an adjunct to rhytidectomy did not result in improved facial rejuvenation in this patient series. The authors' impression is that the benefits of tissue expansion do not justify the added expense, time, and risks associated with using tissue expansion during rhytidectomy.     

A study of the long-term effect of malar fat repositioning in face lift surgery: short-term success but long-term failure

In 1990, the author reported on a series of 403 cases of deep plane face lifts, the first published technique describing the repositioning of the cheek fat, known as malar fat, in face lift surgery. This study examines the long-term results of 20 of the original series in an attempt to determine what areas of the rejuvenated face (specifically, the malar fat) showed long-term improvement. The results were judged by comparing the preoperative and long-term postoperative views in a half-and-half same-side hemiface photograph. The anatomy of the jawline (superficial musculoaponeurotic system [SMAS]), the nasolabial fold (malar fat), and the periorbital diameter were evaluated. The results confirmed that repositioning of the SMAS remained for longer than improvement in the nasolabial fold and that the vertical diameter of the periorbit did not change at all. The early results of malar fat repositioning shown at 1 to 2 years were successful, but the long-term results showed failure of the early improvement, manifested by recurrence of the nasolabial folds. There was, however, continuation of the improved results of the forehead lift and SMAS maneuvers of the original procedure. The conclusion is that only a direct excision will produce a permanent correction of the aging nasolabial fold.     

The biomechanical effects of deep tissue support as related to brow and facelift procedures

The adverse effects of increased tension across a healing wound are well known. However, the effect of closing a wound in layers in order to decrease tension on the epidermis has been a source of controversy. It is hypothesized that deep tissue support decreases skin tension upon wound closure. In order to clarify this issue, a two-part study was designed to address the immediate effects of deep tissue support in vitro using fresh-frozen cadavers and in vivo on patients undergoing scheduled surgery. Closing skin tension was measured at standard reference points in coronal brow lift and rhytidectomy procedures performed with and without galeal closure and superficial musculoaponeurotic system (SMAS) procedures, respectively. Deep tissue support was found to significantly (p less than 0.05) decrease skin tension at the time of skin closure at standard reference points in coronal brow lift and rhytidectomy procedures performed on fresh-frozen cadavers. Similar significant (p less than 0.05) decreases in closing skin tension also were found in vivo in patients undergoing similar surgical procedures. Stress relaxation was not found to play a significant role in contributing to this immediate decrease in closing skin tension. It would appear, therefore, that deep tissue support, in the form of galeal closure and an SMAS procedure in coronal brow lift and rhytidectomy procedures, respectively, provides increased viscoelastic support, producing immediate significant decreases in closing skin tension in these procedures. The beneficial effects on wound healing, scar formation, tension-related trophic skin changes, and possible improved long-term results are discussed.     

The role of the septal reset in creating a youthful eyelid-cheek complex in facial rejuvenation

Resetting of the septum orbitale over the orbital rim, or "septal reset," is the latest step in achieving periorbital rejuvenation in composite rhytidectomy. The first significant step was the addition of orbicularis repositioning to conventional lateral vector deep plane rhytidectomy, followed by orbital fat preservation using the arcus marginalis release and fat transposition over the orbital rim. Those early procedures have been further refined to include the zygomaticus muscles with the orbicularis oculi in the composite flap, or zygorbicular cheek flap, and a septal reset. The septum orbitale reset has distinct advantages over transposition of orbital fat alone, as it creates a firmer undersurface for the lower eyelid. This maneuver will create a truly youthful lower eyelid-cheek complex, as the normal concave aging skeletonization of the periorbit is transformed to a convex contour of youth. The effectiveness of this operation can be demonstrated in most variations of human anatomy, whether congenital or iatrogenic, allowing the plastic surgeon to utilize the septal reset in virtually every patient undergoing and desiring a harmonious facial rejuvenation.     

The extended subperiosteal face lift: a definitive soft-tissue remodeling for facial rejuvenation.

The subperiosteal face lift described by Psillakis has been criticized for not showing a more dramatic improvement over conventional brow/face lift procedures. His approach also has a significantly high incidence of nerve injury. This study reports our anatomic findings and surgical modifications, which have permitted a significant improvement in the safety of execution and clinical results using the subperiosteal face lift concept. Pertinent points of applied local anatomy and dissection techniques are as follows: First, we use extensive interconnected subperiosteal dissection that includes the entire zygomatic arch. This allows better repositioning of the deep soft tissues of the entire upper face, most of the midface, and indirectly, key structures of the lower face. Second, the upward pull of the muscles of the cheek and mouth will produce an elevation of the corner of the mouth, affecting positively the smiling mechanism, the oral frowning, and the jowls. Third, the dissection deep to both layers of the temporal fascia decreases the risk of injury to the frontalis nerve. Fourth, the temporal fascia is used as a lifter and anchoring element of the entire cheek-perioral soft tissues as opposed to the periorbital fibrofatty tissues. This will decrease the risk of injuring the frontal and zygomatic branches of the facial nerve. These modifications have been used in 28 patients. Our rate of patient satisfaction has been high, and no complications with regard to nerve injury have been observed. This compares favorably with our initial 60 patients, in whom the Psillakis or Tessier approach was used. In these patients, there was an 11 and 20 percent rate of nerve injury, respectively.     

Restoring facial shape in face lifting: the role of skeletal support in facial analysis and midface soft-tissue repositioning

Aesthetic analysis in facial rejuvenation has traditionally been subordinate to technical solutions. While concerns regarding correction of facial laxity, a reduction in the depth of the nasolabial fold, and improvement of both the jowl and the jawline are worthy goals in rhytidectomy, the aesthetic concept of restoring facial shape to a more youthful appearance is equally important. Restoring facial shape in face lifting requires an understanding of how the face ages and then the formulation of a treatment plan that is individualized for the patient. Re-establishment of facial contour is significantly influenced by the re-elevation of descended facial fat through superficial musculoaponeurotic system manipulation; it can be approached through a variety of technical solutions. Underlying skeletal support affects not only the appearance of the face in youth but also how the face ages and influences the operative plan in terms of the requirements for fat repositioning. Formulating a treatment plan that is patient specific and based on the artistic goals as influenced by skeletal support is the key element for consistency in restoring facial shape in face lifting.     

Subperiosteal approach as an improved concept for correction of the aging face

A harmonious facial appearance is determined by a balanced relationship among all tissues of the face. With advancing age, balance is lost among the bone, muscle, fat, and skin as progressive changes occur in their volume, shape, position, and consistency. Study of clinical cases and fresh cadaver dissections has led to better understanding of the superficial musculoaponeurotic system (SMAS) and its relationship with the facial muscles and their bony insertions. From these anatomic studies we have developed an improved concept of rhytidectomy with the subperiosteal detachment of all soft tissues from the orbit, upper maxilla, malar bone, and nose. Following this detachment, the soft tissues of the cheek, forehead, jowls, nasolabial folds, lateral canthus, and eyebrows can be lifted to reestablish their youthful relationship with the underlying skeleton. Our 4-year experience includes 105 patients. Sixty percent of these patients were admitted to the hospital and had their procedure under general anesthesia; forty percent, however, had their procedure in an outpatient setting requiring only local anesthesia (lidocaine hydrochloride 1% plus epinephrine) and intravenous sedation (midazolam, ketamine). Complications have been minimal except for temporary paralysis of the frontal nerve in seven patients; guidelines for prevention have subsequently been developed. The subperiosteal rhytidectomy is excellent and appears more natural for rejuvenation of the upper and central face, eyebrows, periorbita, external canthus, cheeks, and nasolabial fold.     

Submental suction-assisted lipectomy without platysmaplasty: pushing the (skin) envelope to avoid a face lift for unsuitable candidates

Patients with submental fullness may not be candidates for a full or short-scar face lift because of medical contraindications, uncontrolled hypertension, a refractory nicotine habit, or anticoagulant medications, or patients may disqualify themselves because of cost, unavailable recovery time, or emotional resistance. Submental suction-assisted lipectomy has traditionally been reserved for younger patients. For older patients, suction-assisted lipectomy is typically used as an adjunct for face/neck lifts. This report describes experiences with suction-assisted lipectomy for older patients who were not face lift candidates, for the aforementioned reasons. The study goals were to better delineate the indications for submental suction-assisted lipectomy, as opposed to a face lift, and to obtain improved results with a less-invasive procedure. A 6-year study involving 132 patients (21 to 73 years of age), of whom 4.5 percent were men, was performed. Eighty-eight patients (67 percent), the primary focus of this study, were more than 40 years of age. Of those 88 patients, 24 patients (18 percent of the 132 patients in this series) were in their forties, 45 (34 percent) were in their fifties, 16 (12 percent) were in their sixties, and three (2.3 percent) were at least 70 years of age. The median follow-up time in this series was more than 1 year. The results were assessed with the five criteria for facial rejuvenation described by Ellenbogen and Karlin. All patients demonstrated improvement, with three to five of the Ellenbogen-Karlin neck rejuvenation criteria being met for each patient. All patients demonstrated an improved submandibular border, a more visible anterior sternocleidomastoid muscle border, and an improved neck angle (as determined with angle measurements). For many patients, all five of the Ellenbogen-Karlin criteria were met. A visible subhyoid depression and a visible thyroid cartilage bulge were the two criteria most often not met. A retrospective evaluation using Baker's preoperative classification of patient types for short-scar face lifts was performed. Results for patients more than 64 years of age (11 patients) were less satisfactory, often with redundant or crepe paper-like skin. Submental suction-assisted lipectomy, as opposed to a face lift, was observed to be a reasonable alternative for older patients who were unable or unwilling to undergo a face lift. Localized fullness in the midline was observed to be the best predictor of a good outcome (even better than age or skin tone). A crepe paper appearance of the skin preoperatively was the best predictor of failure. The surgical anatomical features, technique, advantages, disadvantages, and principles are discussed. Complications and their treatment are addressed. It is concluded that submental suction-assisted lipectomy alone, without platysmaplasty, can be helpful for patients with submental fullness who are unsuitable candidates for a face lift and who accept the limitations of liposuction without platysmaplasty. Suction-assisted lipectomy can sufficiently contract and smooth the skin envelope for selected patients, with less consideration for age than previously proposed.     

Laser blepharoplasty with transconjunctival orbicularis muscle/septum tightening and periocular skin resurfacing: a safe and advantageous technique

Carbon dioxide (CO2) laser blepharoplasty with orbicularis oculi muscle tightening and periorbital skin resurfacing is a safe procedure that produces excellent aesthetic results and diminishes the occurrence of complications associated with skin and muscle resection in the lower lid, particularly permanent scleral show and ectropion. The authors present a review of 196 cases of carbon dioxide laser blepharoplasty and periocular laser skin resurfacing performed at their center from April of 1994 to September of 1998. Of these cases, 113 patients underwent four-lid blepharoplasty, 59 underwent upper lid blepharoplasty only, and 24 underwent lower lid blepharoplasty only. Prophylactic lateral canthopexy was performed in 24 patients. Concomitant procedures (brow lift/rhytidectomy/rhinoplasty) were performed in 92 patients. The carbon dioxide laser blepharoplasty procedure resulted in no injuries to the globe, cornea, or eyelashes. Combined with laser tightening of the orbicularis oculi muscle and septum and periocular skin resurfacing, the transconjunctival approach to lower blepharoplasty preserves lower lid skin and muscle. Elimination of the traditional scalpel skin/muscle flap procedure results in a dramatically lower complication rate, particularly with regard to permanent ectropion and scleral show. Laser shrinkage of the orbicularis muscle and septum through the transconjunctival incision enables the correction of muscle aging changes such as orbicularis hypertrophy and malar festoons. The addition of periocular resurfacing enables the correction of skin aging changes of the eyelid that are not addressed by traditional scalpel blepharoplasty. In addition, lateral canthopexy constitutes an important adjunct to the laser blepharoplasty procedure for the correction of lower lid canthal laxity.     

SMAS-platysma face lift

Correction of laxity in the submental area and of hypertrophic neck cords has been enhanced with the SMAS-platysma face life over that which was achieved with a standard skin face lift. Evaluation of a 6-year experience with the SMAS-platysma face lift reveals that the operation can be safely performed with an acceptably low incidence of complications. The incidence of hematoma and associated complications is less than that which occurs when cervical and submental defatting is performed in conjunction with a skin face lift.     

Transconjunctival orbital fat repositioning: transposition of orbital fat pedicles into a subperiosteal pocket

Rejuvenation of the lower eyelid complex is based on the principle that the contour changes characterizing aging involve not only prolapse of orbital fat but also descent of the cheek tissues, resulting in accentuation of the orbital rim and tear trough groove. When a deep groove is present along the orbital rim in the area of the tear trough deformity, it is advantageous, rather than removing orbital fat, to reposition the fat over the orbital rim through the opened arcus marginalis onto the superior face of the maxilla. Orbital fat repositioning can be accomplished through a transconjunctival approach. The arcus marginalis is exposed and incised, and a subperiosteal pocket is created over the superior face of the maxilla. The subperiosteal pocket shape and location are customized based on the desired location of the orbital fat pedicle; often the origins of the levator superioris labialis and the levator alae nasi muscles are partially dissected. Medial and central fat pedicles are created and rotated over the orbital rim into the subperiosteal pocket. A 6-0 polypropylene externalized sutured is used to fixate the fat pedicle in position. The suture can be removed after 3 to 5 days. Twenty-four patients were followed clinically after orbital fat repositioning, with follow-up ranging from 6 to 30 months. Although the fat pedicle undergoes some variable resorption, the viability of the graft, the texture and contour of the repositioned fat after a healing period of 1 to 2 months, and the excellent patient acceptance are indicative of the viability of orbital fat repositioning.     

In vivo and in vitro bone strain in the owl monkey circumorbital region and the function of the postorbital septum

Anthropoids and tarsiers are the only vertebrates possessing a postorbital septum. This septum, formed by the frontal, alisphenoid, and zygomatic bones, separates the orbital contents from the temporal muscles. Three hypotheses suggest that the postorbital septum evolved to resist stresses acting on the skull during mastication or incision. The facial-torsion hypothesis posits that the septum resists twisting of the face about a rostrocaudal axis during unilateral mastication; the transverse-bending hypothesis argues that the septum resists caudally directed forces acting at the lateral orbital margin during mastication or incision; and the tension hypothesis suggests that the septum resists ventrally directed components of masseter muscle force during mastication and incision. This study evaluates these hypotheses using in vitro and in vivo bone strain data recorded from the circumorbital region of owl monkeys. Incisor loading of an owl monkey skull in vitro bends the face upward in the sagittal plane, compressing the interorbital region rostrocaudally and “buckling” the lateral orbital walls. Unilateral loading of the toothrow in vitro also bends the face in the sagittal plane, compressing the interorbital region rostrocaudally and buckling the working side lateral orbital wall. When the lateral orbital wall is partially cut, so as to reduce the width of its attachment to the braincase, the following changes in circumorbital bone strain patterns occur. During loading of the incisors, lower bone strain magnitudes are recorded in the interorbital region and lateral orbital walls. In contrast, during unilateral loading of the P³, higher bone strain magnitudes are observed in the interorbital region, and generally lower bone strain magnitudes are observed in the lateral orbital walls. During unilateral loading of the M², higher bone strain magnitudes are observed in both the interorbital region and in the lateral orbital wall ipsilateral to the loaded molar. Comparisons of the in vitro results with data gathered in vivo suggest that, during incision and unilateral mastication, the face is subjected to upward bending in the sagittal plane resulting in rostrocaudal compression of the interorbital region. Modeling the lateral orbital walls as curved plates suggests that during mastication the working side wall is buckled due to the dorsally directed component of the maxillary force which causes upward bending of the face in the sagittal plane. The balancing side lateral orbital wall may also be buckled due to upward bending of the face in the sagittal plane as well as being twisted by the caudoventrally directed components of the superficial masseter muscle force. The in vivo data do not exclude the possibility that the postorbital septum functions to improve the structural integrity of the postorbital bar during mastication. However, there is no reason to believe that a more robust postorbital bar could not also perform this function. Hypotheses stating that the postorbital septum originally evolved to reinforce the skull against routine masticatory loads must explain why, rather than evolving a postorbital septum, the stem anthropoids did not simply enlarge their postorbital bars. © 1996 Wiley-Liss, Inc.     

The SMAS and the nasolabial fold.

In a series of histologic sections and clinical and cadaver dissections, the superficial musculoaponeurotic system (SMAS) is seen to become the investing fascia of the zygomaticus major and minor muscles in the medial cheek. The pull on the cheek flap during rhytidectomy is diffused by the attachment of the SMAS to these muscles. I believe that this attachment accounts for the minimal change in the nasolabial crease after a Skoog-type sub-SMAS face lift.     

Transblepharoplasty endoscopic subperiosteal midface lift

The use of endoscopy in the transblepharoplasty midface lift is essential for preventing the complications of facial nerve injury and bleeding. Complete observation allows precise dissection and release of all structures in the composite flap. This technique fully preserves the zygo-orbicular nerve plexus and prevents denervation of the orbicularis oculi and zygomaticus muscles. Blind dissection has a significant probability of denervation of the entire zygo-orbital muscle complex, and avulsion of the zygomaticofacial vessels, with associated postoperative bleeding complications. The modification involving suturing of the "vest" of the combined lateral orbital periosteal and superficial layers of the deep temporal fascia over the elevated "pants" of the orbicularis periosteal flap provides very secure fixation for suspension of the lower eyelid and midface. The use of slowly absorbable polydioxanone sutures for this technique prevents the problems caused by permanent sutures beneath the very thin skin of the lateral canthal area. Careful trimming of the prominent roll of the orbicularis muscle that often develops with suspension eliminates the uneven contour and yields a smooth lower lid appearance. The details and modifications described should decrease the complications and morbidity that can occur with this procedure and provide for a more precise and reliable procedure for rejuvenation of the lower eyelid and midface.