Lateral Orbital Rim Research Articles

Superolateral Approach to Orbital Tumors

The conventional lateral approach to the orbit (Krönlein) does not allow a satisfactory view of the superior part of the orbit and the operative field is rather narrow. Therefore, large tumors which have developed not only laterally but also superiorly are usually approached transcranially. The craniotomy and exposure of the dura may be avoided when the tumor does not extend too far posteriorly and medially, by turning a larger orbital bone flap than the Krönlein's one. This technique was described by Nakamura as "type I orbitotomy" and can be referred to as a superolateral approach. After a bicoronal skin incision, a free orbital bone flap is cut. It includes the lateral orbital rim, a large external part of the superior orbital rim, and the lateral orbital wall. From 1985 to 1990 this approach was performed on 23 patients presenting with lacrimal gland tumors in 14 cases (11 pleomorphic adenomas, 2 adenoid cystic carcinomas, 1 adenocarcinoma), schwannomas in 2 cases, dermoid cyst in 1 case, hydatic cyst in 1 case, cavernous hemangiomas in 2 cases, inflammatory pseudotumor in 1 case, and mucoceles in 2 cases. This superolateral approach provides a wider exposure to the superolateral orbit than the classical Krönlein's approach and avoids the drawbacks of a craniotomy. A direct incision through the eyebrow can be used for bald people or for patients in poor condition.

Temporal Contour Deformity After Coronal Flap Elevation

Temporal contour deformity is defined as a concavity or depression in the temporal region located superior to the zygomatic arch and immediately posterior to the lateral orbital rim. The deformity can present as a consequence of extended coronal flap elevation for exposure of the lateral craniofacial skeleton. This study describes the anatomical and pathological features of the deformity and identifies causative factors. The series consists of unilateral temporal contour deformities after coronal flap elevation in 6 patients. A standardized data sheet was used in documenting details of the initial temporal dissection, clinical findings, and radiological features. Elevation of the temporal soft tissues was based on a qualitative analysis of coronal magnetic resonance imaging (MRI) scans comparing the affected and the unaffected temporal regions. The MRI studies demonstrated normal volume of the temporalis muscle in all cases, with no evidence of atrophy or disinsertion of the muscle. Diminution in the volume of the superficial temporal fat pad was identified in 4 patients, whereas inferior displacement or prolapse of the superficial temporal fat pad was noted in 2 patients.

Safe Management of Dermolipomas

Most reports on dermolipomas describe the serious complications arising from their removal. The aim of this article was to describe a safe and effective method of removing dermolipomas. Forty-five consecutive eligible patients underwent surgical removal of their dermolipomas over a 20-year period. Of the two complications, only one, a restrictive symblepharon, required further surgery. The techniques for excising simple dermolipomas and dermolipomas associated with a deformity of the lateral canthal angle are described. Safe removal of dermolipomas may be accomplished with minimal resection of the conjunctiva, including the pilosebaceous area, identification of contiguous structures, and removal of only that portion of the dermolipoma anterior to the lateral orbital rim.

Hertel Exophthalmometry without Orbital Rim Contact

The Hertel exophthalmometer is the most widely used instrument for the measurement of globe malposition, but an absent or damaged lateral orbital rim will preclude its application. To circumvent this shortcoming, the authors have developed a fixation adapter that attaches to a standard Hertel instrument and transfers fixation to the forehead and nasion from the lateral orbit. The adapter design is presented and discussed, along with illustrative clinical cases. A study of 30 healthy patients was performed to assess the validity of the adapter with respect to the Hertel standard. The agreement was then evaluated by comparing the Hertel adapter measurements from each patient with that of the adapter. A Wilcoxon statistic was performed to assess differences in the paired values from each patient for both techniques. Analysis on a sample (n = 30) of a healthy adult population does not show a statistical difference between the Hertel adapter and the adapter data (P > 0.05). In addition, more than 90% of the differences fall within +/- 1 mm (standard deviation = 1.02 mm) of the means for both eyes, which is within the accepted variance for the Hertel instrument. The new fixation adapter promises to become useful in assessing trauma and surgical cases where the lateral orbital rim has been violated and will expand the application of Hertel exophthalmometry to these situations.

Metopic Synostosis

Our study applied a method of using 14 clinically relevant measurements of CT scan images to document skeletal dysmorphology in patients with metopic synostosis to determine the effectiveness of their surgical procedure after a minimum of 1 year. Ten consecutive patients with metopic synostosis who underwent a standard surgical procedure were reviewed. Preoperative and postoperative (>1 year) CT scans were compared with those of age-matched controls. Percentages of normal were then compared for significant differences. Preoperative cranial vault measurements revealed a narrowed anterior inter-coronal distance at 92 percent of normal. Orbital measurements showed a narrowed anteromedial wall interorbital distance at 79 percent of normal, a narrowed lateral orbital wall distance at 94 percent, and an elevated medial orbital wall protrusion beyond the plane of the lateral orbital walls at 115 percent. After surgery, the intercoronal distance was significantly corrected to 101 percent, the anteromedial wall interorbital distance was improved but remained undercorrected at 90 percent, and the medial wall protrusion was significantly decreased to 98 percent of normal. Quantitative measurements of CT scan images confirmed clinically observed physical findings in unoperated trigonocephaly to be orbital hypotelorism, retruded lateral orbital rims, and a narrowed bitemporal width. The surgical technique corrected the lateral orbital wall aspects of the deformity as well as the narrowed anterior cranial vault width and improved the orbital hypotelorism. (Plast. Reconstr. Surg. 93: 16, 1994.)

Optic Nerve Sheath Fenestration Through a Lateral Canthotomy Incision

Optic nerve sheath fenestration is an increasingly useful surgical technique for relief of visual loss due to a number of optic disc pathologic conditions. To date, surgeons have employed either a medial approach with disinsertion of the medial rectus muscle or a lateral approach with removal of the lateral orbital rim to gain access to the retrobulbar optic nerve. We report herein a technique for approaching the optic nerve through a lateral canthotomy incision that does not require removal of bone or disinsertion of an extraocular muscle. It has been used to provide ready surgical exposure of the optic nerve in 17 eyes of 14 patients. This technique combines the advantages of lateral exposure of the optic nerve with an ease of operation similar to that of the medial approach.

Use of Porous High-Density Polyethylene Implants in Temporal Contour Reconstruction

A temporal contour deformity is characterized by a concavity or depression in the soft-tissue contour of the temporal region and is associated with exaggerated relief of the lateral orbital rim and the zygomatic arch. The etiology of the deformity is varied, comprising any condition that results in displacement, atrophy, or absence of the temporalis muscle or the superficial temporal fat pad. We describe reconstruction of this deformity with porous high-density polyethylene implants in 16 consecutive patients, treated between July 1988 and September 1990. The etiology of the deformity and the surgical treatment are described. The results of treatment are assessed on long-term follow-up, ranging from 2 to 4 years postoperatively.

A superior and inferior orbital rim-based orbitometer

In exophthalmometry, alterations in the lateral orbital rim cause inaccuracy in serial readings when this structure is used as a fixation base. The authors have found that, compared with the Hertel-type lateral-rim-based instrument, an exophthalmometer based on the superior and inferior orbital rim areas bilaterally appears to be more accurate and is more comfortable, making it especially useful with pediatric patients. That the new exophthalmometer can be aligned at the mid-pupil horizontally and vertically with a vertical fixation bar enhances accuracy. In addition, the device can measure hypo-ophthalmos and hyperophthalmos by virtue of a vertical bar gradient scale.

A Superior and Inferior Orbital Rim-Based Exophthalmometer (Orbitometer)

In exophthalmometry when the lateral orbital rim is used as the instrument's fixation base, any alteration in the rim will render serial measurements inaccurate. The exophthalmometer we describe (technically, an "orbitometer") uses the superior and inferior orbital rim areas as a base of reference, making it particularly useful in lateral orbitotomy procedures. This instrument can be aligned at the midpupil horizontally and vertically with a vertical fixation bar. In addition, a vertical bar gradient scale allows measurement of hypoophthalmos and hyperophthalmos.

Miniplate Reconstruction of the Lateral Orbital Rim after Orbital Decompression for Graves Disease

Removal of lateral orbital bone with or without simultaneous removal of the lateral orbital rim is an accepted method of orbital decompression for Graves disease. Once removed, the bone is no longer available for reconstruction and secondary complications such as rounding of the canthal angle, canthal dystopia, and globe dystopia may result. The authors replaced the excised bone with a titanium miniplate to protect the globe and fixate the lateral canthal tendon in 18 patients (33 orbits). The orbital rim and lateral orbital wall were completely removed, and the inner aspect of the orbit was enlarged with a cutting burr. A standard titanium miniplate was then anchored to remaining bone, and soft tissue was secured to the miniplate to reconstruct the lateral canthus. The results, as manifest by appearance of the lateral canthus and position of the eyelid in apposition to the globe, were graded as excellent in all patients and orbits. There were no early or late complications. Miniplate reconstruction of the lateral orbital rim after decompression for Graves disease allows the beneficial affect of lateral decompression and preserves the functional aspect of the lateral orbital wall.

Orbital Decompression for Graves' Disease: Exposure Through a Modified Blepharoplasty Incision

A "transorbital" three-wall decompression through a modified blepharoplasty incision was used to treat 19 orbits for either cosmetic disfigurement or optic neuropathy. In the 14 orbits with disfigurement, surgical retroplacement averaged 5.2 mm; vision improved to 20/40 or better in four of five eyes with optic neuropathy. Complications attributed to the surgery included: acquired strabismus (two transient, one permanent) and infraorbital hypesthesia (one transient, one permanent). This technique's advantages are: 1) a single incision with wide exposure, 2) a low incidence of permanent strabismus, 3) a lateral orbital rim and canthal tendon preservation, and 4) a large reduction in proptosis.

Modified Supraorbital Craniotomy

The authors present a surgical approach that incorporates the frontal sinus and extends a supraorbital craniotomy to include the lateral orbital rim and zygoma. The craniotomy provides wide exposure of the anterior fossa, orbit, ipsilateral middle fossa, and cavernous sinus. The procedure can be performed easily, and the bone flaps can be secured rapidly back into the anatomical position at the time of closure. This modified supraorbital craniotomy is ideal for large benign lesions originating along the sphenoid wing or orbit that expand into the anterior fossa.

Orbital rim and malar advancement for unilateral coronal synostosis in the older pediatric age group

The authors describe a technique for lateral orbital rim and malar advancement in patients in the older pediatric age group. The technique makes use of a strip craniotomy containing the supraorbital margin, greater sphenoid wing, and temporal bone, with en bloc inclusion of the lateral orbital rim, zygoma, and malar prominence. The method allows a contoured yet stable construction secured in a tongue-in-groove fashion with plate-and-screw fixation. It creates a symmetrical reconstruction of both frontal and lateral orbital aspects in the untreated or inadequately treated older plagiocephalic child with orbital dystopia. The accompanying malar recession is likewise corrected.

Temporal and Malar-Zygomatic Reduction and Augmentation

The temporal fossa, zygomatic arch, and malar-midface should be considered jointly when augmentation of the temporal area or reduction of the zygomatic arch are to be carried out. These anatomic areas relate so closely to one another that altering one affects the other. In addition, augmentation of the malar-midface area may be done if one of the other two procedures is to be considered, or if a brow lift, subperiosteal face lift, or other reason for using a coronal incision exists. Use of the coronal incision for malar augmentation is probably not justified because of the large amount of surgery required in spite of the lesser morbidity associated with this approach in terms of amount of infections, lip stiffness, and hypesthesia. Planning a surgical procedure must be done in the office, by examining the patient at eye level to determine the amount of zygomatic arch reduction and the amount of temporal fossa augmentation necessary. Similarly, the three zones of the malar-midface complex must be assessed, with the amount of augmentation of each zone determined prior to the day of surgery. The surgical procedure is then executed through a coronal incision, with the dissection extending down to the zygomatic arch. If the temporal muscle is to be elevated out of its fossa, it is cut on its anterior, superior, and posterior edges, elevating it out of its fossa so that a Proplast implant, typically 3 to 4 mm thick and finely tapered on its superior and posterior edges, with suturing done anteriorly, may be inserted. The muscle is then resutured to its aponeurosis on all three edges. If the zygomatic arch and malar-midface area are to be approached, the dissection is carried to the deep and superior edge of the zygomatic arch, and the periosteal elevator is used to elevate the soft tissue off the lateral and inferior edge. The arch and malar-midface are cleared of soft tissue, extending the tunnel to the upper buccal sulcus. The arch is then reduced with a contouring burr to the thinness desired. Alternatively, the malar-midface area may be augmented with synthetic material precisely positioned, with a suture around the zygomatic arch, holding it in position as measured from the lateral orbital rim. The incision in the temporal fascia is then resutured, and the coronal incision is closed.(ABSTRACT TRUNCATED AT 400 WORDS)

Surgical Correction of Tessier Number 8 Cleft

The number 8 Tessier cleft can be a discrete horizontal shadow at the level of the lateral canthus of the palpebral fissure or a true coloboma with absence of the commissure between the upper and lower eyelids. A surgical technique, which has been used in eight patients, is described to correct this congenital defect. Four flaps are created and transposed as two Z-plasties. The lateral canthal ligament is fixed to the lateral orbital rim, and the orbicularis muscle is interdigitated to restore its continuity. This procedure reconstructs the depth of the conjunctival fornix, provides proper form and length to the palpebral fissure, and restores continuity and an anatomic angle to the malformed canthus.

Postaural apocrine hydrocystoma

Benign apocrine hydrocystoma is a rare lesion, especially in the postauricular region, the commonest site being the lateral orbital rim. It is a slow growing, asymptomatic transluscent swelling whose definitive diagnosis can only be made by histopathological study and the chemical analysis of the fluid. Surgical excision in toto is the treatment of choice. A case of benign apocrine hydrocystoma in the postauricular region is described with review of relevant literature.

Floating C-shaped orbital osteotomy for orbital rim advancement in craniosynostosis: preliminary report

A method of lateral orbital rim advancement is described for periorbital deformities associated with coronal and metopic synostosis in infants. The technique offers the advantages of a smooth lateral rim contour and improvement in accompanying malar recession. In 13 patients with follow-up periods of up to 2 years following surgery, improved orbital contour has been appreciated. Further observation is warranted to determine whether this improvement will last into adulthood.

Minimizing and measuring lens dose when giving cranial irradiation.

Three different techniques of administering cranial irradiation were used to determine the dose to the lens as measured in the Rando phantom. The techniques employed were as follows: (1) the central axis of the radiation beam was placed at the thickest portion of the cranium; (2) the central axis of the radiation beam was placed at the lateral orbital rim (bony canthus); (3) the central axis of the radiation beam was placed at the thickest portion of the cranium but with the beam angled 5 degrees posteriorly away from the eye. Thermal luminescent dosimeters (TLD) were placed in a phantom, at a point determined from a life-sized anatomical section of the plane through the midsection of the eye, to be at the location of the posterior capsule of the lens. In addition, TLDs were placed on the outer surface of the phantom head, directly lateral to the location determined to be where the lens would lie. With equally weighted lateral opposed beams, delivering a midplane dose of 200 cGy, the TLDs at the point of the lens measured 21, 9.9 and 10.6% of the midplane doses from the three techniques respectively. TLDs placed directly lateral to the lens on the surface of the phantom head gave an approximation of the lens dose, particularly when techniques 2 and 3 were used. Isodose curve generated by a General Electric treatment planning computer gave lens doses similar to those of the phantom data for each of the three different radiotherapy techniques. Cranial irradiation should be carried out by either technique 2 or technique 3 to minimize radiation dose to the lens.

Bending but not breaking the supraorbital bar.

Surgical bending or contouring of the supraorbital bar may cause inadvertent fractures during craniofacial surgery. Wires may be placed in the bony segments themselves to facilitate reshaping with the Tessier rib bender. The wires are especially helpful in stabilizing the more acute curve at the lateral orbital rim.

Periorbital marginotomies: Anatomy and applications

The application of craniofacial techniques has led to a greater variety of methods for operative exposure. In the orbital region, the inferior marginotomy of Tessier is a valuable adjunct in the reconstruction of severe orbital floor fractures and their sequelae. This concept has been extended to the superior, lateral, and medial orbital rims to improve the exposure of the respective orbital wall. These marginotomies have been used for a variety of problems. There have been no complications related to the inclusion of a periorbital marginotomy, and its use in appropriate patients is strongly recommended.