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Biomedical subjects

D M Knize

Publications and source records attributed to D M Knize.

At least 19 recordsLinked to original sources
PubMed2000

Muscles that act on glabellar skin: a closer look.

The coronal incision forehead lift became a component of the face-lift procedure 35 years ago and increased the cosmetic benefit for the facial aesthetic surgery patient. Later, this enhanced cosmetic effect achieved from eyebrow resuspension was complemented by treatment of the glabellar skin lines by modifying corrugator supercilii and procerus muscle function through the same coronal incision. In recent years, newer procedures for treating the corrugator supercilii and procerus muscles by using endoscopy or limited incision techniques have eliminated the need for the coronal incision. With these newer techniques has come a renewed interest in the surgical anatomy of the muscle complex that acts on glabellar skin. This study was designed to examine the current understanding of the anatomy of these muscles and to resolve misconceptions and controversy concerning them. Fresh cadaver dissections and simulated muscle action studies done on the glabellar musculature of four specimens were correlated with nerve blockade studies performed in 10 subjects on the temporal and zygomatic branches of the facial nerve. The presence of the depressor supercilii muscle as a distinct entity was confirmed. The little-appreciated oblique head of the corrugator supercilii muscle was identified. The conclusions from this study suggest that the transverse head of the corrugator supercilii muscle produces the vertical component of the glabellar skin line and also contributes to the formation of the oblique component of the glabellar skin line. The oblique head of the corrugator supercilii muscle, the depressor supercilii muscle, and the medial head of the orbital portion of the orbicularis oculi muscle all appear to depress the medial head of the eyebrow and contribute to the formation of the oblique glabellar skin line. The nerve block study provided evidence that the zygomatic branch of the facial nerve supplies the three medial eyebrow depressor muscles, which opens the possibility for future nerve ablation techniques to control the action of the medial eyebrow depressor muscle group. This nerve block study also supports the concept of "physiologic" elevation of the medial eyebrow as an effective component of foreheadplasty.

Adult↗
PubMed1999

Periauricular face lift incisions and the auricular anchor.

There is one problematic part of the facialplasty procedure that has been addressed with relative infrequency in the plastic surgery literature. This is the aesthetic management of the periauricular incisions and the resultant wound. The following problems associated with the design and closure of the periauricular incisions are recognized: (1) wide, hypertropic, or hypopigmented scars; (2) excessively elevated temporal hairline and a postauricular hairline "step" deformity; (3) "hidden" or "buried" tragus; (4) low, visible mastoid skin scars; and (5) deformed ear lobule or "pixie ear" deformity. Prevention of these undesirable results of facialplasty and cosmetic enhancement of the periauricular area for the facialplasty patient is the surgical challenge about which this article is concerned. The author's approach to the management of the periauricular area has been used successfully on 770 patients since 1985. This approach includes a unique incision design as well as a technique for internally splinting the periauricular incision at the time of wound closure. The incision design can eliminate the problems of elevated temporal hairline, disruption of the postauricular hair-line, and visible mastoid skin scarring. The incorporated internal splinting technique reduces skin level closure tension to improve the quality of the skin scar formation. This approach further allows for retaining a natural-appearing shape of both the tragus and the lobule of the ear. The biomechanical basis for the internal splinting technique was examined by measuring the forces required to transpose facialplasty flaps to the periauricular area. The auricular cartilage was demonstrated to be a remarkably stable structure to which these flaps could be anchored.

Cicatrix↗
PubMed1998

Limited incision submental lipectomy and platysmaplasty.

Thirty years ago, submental fat deposition and platysma band formation were inadequately addressed by surgeons attempting facial rejuvenation procedures. Simple skin envelope tightening as practiced commonly at that time resulted in reappearance of submental bands within months, disappointing both patient and surgeon. During each subsequent decade, existing techniques for aesthetic surgical treatment of the submental and neck areas were refined, and new techniques were introduced. The earliest in this evolution of surgical approaches to rejuvenate the aging submental region was direct excision of redundant anterior cervical skin and platysma muscle bands. Later, periauricular incision approaches without anterior skin excision were used to address platysma muscle bands and remove excess submental fat. Today, the standard approach for submental and anterior neck rejuvenation is some variation of "corset" platysmaplasty and suction-assisted lipectomy both superficial and deep to the platysma muscles. The introduction of endoscopy to plastic surgery has stimulated interest in performing many surgical procedures through limited-incision approaches. While endoscopic techniques may not have a clear application for the submental area, redundant submental soft tissues producing obliquity of the cervicomandibular angle may be treated through a single submental incision approach under direct vision. A technique practiced by the author since 1981 for performing submental lipectomy and platysmaplasty through a single limited anterior submental incision without skin excision is described and discussed. Postoperative compression of the submental area with an elastic garment facilitates smooth skin contraction and redraping for all patients except those with poor or no residual skin elasticity.

Adolescent↗
PubMed1998

Reassessment of the coronal incision and subgaleal dissection for foreheadplasty.

Thirty years ago, the aging upper face was generally ignored by surgeons performing facial rejuvenation surgery. Ultimately, the coronal incision forehead lift technique became an accepted procedure, with most surgeons raising the forehead flap at the subgaleal plane. These surgeons found the subgaleal plane to be the "natural" or most accessible dissection plane to use, and it continues to be the most commonly used dissection plane for foreheadplasty today. However, some surgeons have begun to advocate using the subperiosteal plane, and controversy surrounds the question of which dissection plane is more surgically sound for raising a forehead flap. On the basis of 25 fresh cadaver dissections and more than 20 years of clinical experience with foreheadplasty, the author concludes that dissection done at the subperiosteal rather than the subgaleal plane provides greater benefit to the patient. Although both subgaleal and subperiosteal planes can provide relative ease of dissection, elevation of the forehead flap at the subperiosteal plane can maximally preserve blood supply for the forehead flap and predictably preserve long-term frontoparietal scalp sensation. The deep division of the supraorbital nerve, which provides sensation to the frontoparietal scalp, is placed at risk for transection with subgaleal elevation of the forehead flap. The skin incision approach chosen for the forehead flap can also affect postoperative frontoparietal scalp sensation. The deep division of the supraorbital nerve will always be transected by a coronal incision approach for forehead flap elevation, with dissection done at either the subgaleal or the subperiosteal level. Only limited scalp incisions placed to avoid the course of the deep division of the supraorbital nerve can avoid transecting this nerve, and only subperiosteal dissection of the forehead flap can predictably preserve this nerve while elevating the forehead flap.

Endoscopy↗
PubMed1997

Use of preoperative subcutaneous "wetting solution" and epidural block anesthesia for liposuction in the office-based surgical suite.

Uniform saturation of subcutaneous fat using the "wetting solution" formula described by Klein for his "tumescent technique" has been shown to decrease operative blood loss associated with liposuction procedures and to eliminate the requirement for general anesthesia for selected patients. However, we found this infusate provided an inadequate level of anesthesia for many of our patients. We use preoperative infusion of Klein's epinephrine and lidocaine containing wetting solution in our lipoplasty practice only for control of blood loss and postoperative pain. Our anesthetic of choice for liposuction is the epidural block technique, which provides consistent intraoperative comfort for the patient. We report our experience with 85 consecutive lipoplasty patients who underwent liposuction under epidural anesthesia after subcutaneous fat perfusion with Klein's wetting solution. Our epidural block technique uses the rapidly metabolized local anesthetic agent, chloroprocaine, which has the lowest systemic toxicity risk of any local anesthetic agent. Chloroprocaine's anesthetic characteristics are particularly well suited for the outpatient surgery patient with few undesirable side effects.

Ambulatory Surgical Procedures↗
PubMed1996

An anatomically based study of the mechanism of eyebrow ptosis.

The development of eyebrow ptosis with aging is commonly attributed to progressive laxity of scalp and forehead soft tissues. If the change in eyebrow position with aging resulted entirely from this basic mechanism of tissue stretching, uniform lowering of the medial and lateral eyebrow segments should occur. Clinical observations show, however, that the lateral eyebrow segment usually becomes ptotic earlier than the medial segment, indicating that a more complex mechanism exists. To clarify this process, anatomic studies were done on 20 (40 half-head) fresh cadaver specimens. Histologic studies also were performed to complement the gross anatomic findings. These studies confirm that the mechanism producing eyebrow ptosis has a relatively greater effect on the lateral eyebrow segment. The lateral eyebrow has less support from deeper structures than the medial eyebrow, and the balance of forces acting on the eyebrow selectively depresses the lateral segment. Structures that may promote mobility and gravitational descent of the eyebrow, especially the lateral eyebrow segment, are (1) the galea fat pad, (2) the preseptal fat pad, and (3) the subgalea fat pad glide plane space. Three forces that act on the lateral eyebrow are (1) frontalis muscle resting tone, which suspends that eyebrow segment medial to the temporal fusion line of the skull, (2) gravity, which causes the soft-tissue mass lateral to the temporal line to slide over the temporalis fascia plane and push the lateral eyebrow segment downward, and (3) corrugator supercilii muscle hyperactivity in conjunction with action of the lateral orbicularis oculi muscle, which can antagonize frontalis muscle activity and directly facilitate descent of the lateral eyebrow. The axis point for these forces is the temporal fusion line of the skull near the superior orbital rim. The interaction of those structures and forces contributing to the mechanism producing eyebrow ptosis is discussed. Derived concepts are applied to the execution of the forehead lift procedure.

Cadaver↗
PubMed1996

Limited-incision forehead lift for eyebrow elevation to enhance upper blepharoplasty.

Treatment of eyebrow ptosis to enhance the cosmetic effect from blepharoplasty is commonly done with a forehead lift using a coronal incision approach. The coronal scalp incision is associated with the annoying sequelae of frontoparietal scalp numbness, itching, and paresthesias, all of which can be permanent. A forehead lift technique with temporal scalp incisions only 4.5 to 5.0 cm in length can produce a result comparable with that of the coronal incision approach when combined with transpalpebral resection of the corrugator supercilii muscles and transection of the procerus muscle. This eyebrow elevation technique, like the endoscopic approach, minimizes the risk of permanently injuring the supraorbital nerve branches that innervate the frontoparietal scalp. Unlike the approach using only endoscopy, however, this technique can effectively treat cases of advanced eyebrow ptosis. The appropriate area of eyelid skin for excision may be difficult to assess when a forehead lift and upper blepharoplasty are done concomitantly. The described forehead lift incorporates a method to determine this area. This forehead lift technique, combined with a technique for protecting against overresecting upper eyelid skin, is described as used effectively on 140 blepharoplasty cases followed for 3 months to 4 years.

Eyebrows↗
PubMed1995

A study of the supraorbital nerve.

A detailed description of the anatomical relationships of the supraorbital nerve as it courses across the forehead and under the scalp cannot be found in most anatomy textbooks, and illustrations of the nerve beyond the superior orbital rim frequently misrepresent its course. Because the supraorbital nerve is a structure at risk in many plastic surgical techniques, the plastic surgeon would benefit from a clearer understanding of its anatomy and function. The supraorbital nerve was studied anatomically in 12 (24 half-head) fresh cadaver specimens, and its sensory distribution was studied in 30 living subjects using selective nerve blocks. Beyond the orbital rim, the supraorbital nerve has two consistently present divisions: (1) a superficial (medial) division that passes over the frontalis muscle, providing sensory supply to the forehead skin and only to the anterior margin of the scalp in 90 percent of the study subjects; and (2) a deep (lateral) division that runs cephalad across the lateral forehead between the galea aponeurotica and the pericranium as the sensory nerve to the frontoparietal scalp. When a forehead lift is performed, injury to this deep division causes most of the distressful sequelae of scalp numbness and paresthesia. Unlike the superficial division, the course of the deep division in all cadaver specimens and its sensory distribution in all living volunteer subjects was consistent. This study has application for any procedure requiring scalp or forehead incisions, such as the forehead lift and the endoscopic facial techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Eyelids↗
PubMed1995

Transpalpebral approach to the corrugator supercilii and procerus muscles.

The most effective method for treating glabellar area skin contour irregularities produced by hyperactive corrugator supercilii and/or procerus muscles is resection of the former and at least transection of the latter. The usual surgical approach is a coronal incision, which produces recognized sequelae of scalp or prefrontal hairline scarring and scalp dysesthesia; potential complications include injury to the frontal branch of the facial nerve, postoperative alopecia, and excessive recession of the frontal hairline. Hyperactive corrugator supercilii muscles may be excised and procerus muscles transected without a coronal incision. These muscles can be treated through an upper blepharoplasty incision without compromise to the blepharoplasty procedure. A transpalpebral technique as performed on 40 patients followed 6 to 24 months is described, and the cadaver and nerve block studies upon which this technique is based are discussed. The postoperative cosmetic improvement of the glabellar area is comparable in appearance with that achieved from a coronal incision approach.

Face↗