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D M Knize

Publications and source records attributed to D M Knize.

12 recordsLinked to original sources
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↗