A new instrument design for orbital floor osteotomies performed by an intraoral approach

A new osteotome is described that enables the creation of an osteotomy of the orbital floor by an intraoral approach. The osteotome is S shaped and 11 cm long, with a curved cutting edge that is inserted like a hook onto the orbital floor. The main body and striking head of the osteotome are located just outside of the oral cavity. The S shape of the handle allows for ease of both insertion and instrument use. The new osteotome makes it possible to follow a specifically designed osteotomy line along the orbital floor, ensuring a rapid and reliable procedure.     

Esthetic incisions in traumatology involving the mid-face region

For exposure of the facial bones and orbital floor, various types of incisions can be employed. For exposing the orbital rim, a subciliary incision may have the disadvantage of producing chronic edema and shortening of the lower lid. The transconjunctival approach combined with lateral canthotomy avoids an external scar and allows sufficient exposure of orbital floor and zygomatico-frontal suture line. The placements of implants and osteosynthesis are then possible. In severe midfacial trauma the authors prefer temporo-temporal incision combined with a conjunctival approach, lateral canthotomy and intraoral access to the zygomatico-maxillary area.     

Orbital volume measurement in the management of pure blowout fractures of the orbital floor

With the recent advent of accurate orbital volume assessment by computed tomography, a retrospective analysis was made of 31 patients with 'pure' blowout fracture of the orbital floor, managed either surgically or conservatively, to determine whether orbital volume measurement could provide an additional parameter of use in the management of such fractures. There was a significant difference in orbital volume discrepancy between patients managed surgically or conservatively suggesting that this investigation may be of use in decision making on surgical intervention in patients with orbital blowout fractures.     

Lacrimal obstruction after migration of orbital floor implant

A 7-year-old girl developed epiphora, recurrent purulent conjunctivitis, and dacryocystitis 32 months after the repair of a traumatic orbital floor fracture. Dacryocystography and surgical exploration revealed that migration of the orbital floor implant had caused obstruction of the nasolacrimal duct at the sac. Migration of the implant was probably due to a failure to anchor the implant properly to bone.     

A histogram-based algorithm for semiautomated three-dimensional craniofacial modeling

RATIONALE AND OBJECTIVES: I conducted a study designed to facilitate thresholding and reduce volume averaging in three-dimensional (3D) computed tomography (CT) craniofacial modeling. METHODS: Three-dimensional CT reconstructions of orbits from two cadavers and seven clinical cases were generated from paired axial and coronal data. A histogram-based algorithm that was based on preliminary phantom and craniofacial specimen trials was applied to orbital data to identify volume averaged regions of thin bone to be used in conjunction with standard bone thresholds. Region-of-interest measurement of the orbital floors on the original two-dimensional slice data assessed algorithm performance. RESULTS: In five of the nine cases (55%), configuration of the superimposed histograms predicted regions of volume averaging. In only one case did such a region localize to the orbital floor. In the remaining four cases, the air-mucosa interface deep to the orbital floor was identified by the histogram method. CONCLUSION: Operator-dependent editing remains superior to this histogram-based algorithm in reducing volume averaging in 3D craniofacial modeling.     

Gelfilm and blowout fractures

A variety of alloplastic and natural substances have been utilized for support of the orbital floor following a blowout fracture. The employment of Gelfilm is herein recommended for the smaller floor defects. Sterile Gelfilm is manufactured from denaturated collagen, is 0.075 mm. thick, and is known to be tolerated well by ocular tissues. Complete absorbsion of Gelfilm occurs in two to three months, obviating the need for removal of a prosthetic material or the lifetime presence of an alloplast in the orbit. In contrast to autografts no additional surgery is required for its preocurement.     

Manufacturing and microscopical characterisation of polyurethane nerve guidance channel featuring a highly smooth internal surface

The present study demonstrates the possibility of manufacturing polyurethane [ChronoFlex (CF)] nerve guidance channels (NGCs) featuring a highly smooth internal surface. Comparative SEM and AFM observations prove marked differences between the internal surface microgeometry of Silastic and CF channels. SEM of CF samples shows a surface with no detectable roughness, while Silastic channels show transversal rows along the entire surface. AFM digital image of Silastic samples show a surface with a rough microgeometry defined by a tridimensional pattern with peaks up to 1400 nm. AFM digital image of CF samples show, indeed, an essentially flat microgeometry with the highest level at 545 nm. These preliminary results suggest that the association of an innovative sequential deposition manufacturing technique with the new CF polyurethane may produce NGCs with a smoother surface microgeometry, in comparison to NGCs obtained from commercial Silastic tubes.     

An analysis of objective quality indicators on Year Book citations: implications for MEDLINE searchers

OBJECTIVE: To develop objective criteria with which to identify patients with zygomatic complex (ZMC) or midface fractures who require a surgical exploration and treatment of the orbital component of their fracture to prevent postoperative enophthalmos, diplopia, or malar depression. DESIGN: Nonrandomized, prospective management of facial trauma patients. SETTING: Urban, university referral center. PARTICIPANTS: Ninety-seven patients with facial fractures (72 with ZMC fractures and 25 with midface fractures) who presented to the maxillofacial and oculoplastics trauma teams at the University of Cincinnati, Cincinnati, Ohio, for management. INTERVENTION: The decision whether to include an orbital exploration as part of the management plan was made based on a specific set of physical and radiological criteria that are detailed in the text. OUTCOME MEASURE: Patients were evaluated postoperatively for possible complications related to the orbital and periorbital portions of their fractures. RESULTS: Thirty-four percent of the study patients (30% of the patients with ZMC fractures and 44% of the patients with midface fractures) underwent orbital rim exposure and orbital floor exploration as part of their fracture management. Sixt-six percent of these patients (70% of the patients with ZMC fractures and 56% of the patients with midface fractures) were managed without orbital exploration. Postoperatively, none of the patients who did not undergo exploration experienced diplopia or enophthalmos and only 1 patient had a residual malar depression. CONCLUSIONS: The criteria reported herein allow surgeons to identify the minority of patients with midfacial and ZMC fractures who require an orbital exploration for optimal fracture management. Orbital exploration, and its potential complications, can be avoided in the majority of patients with ZMC and midface fractures without significantly increasing the risk of morbidity related to the orbital component of their fractures.     

Effect of acid concentration on chromogen formation from hexoses in sulfuric acid-based reactions

Dynamic mechanical properties of Silastic HP-100 finger joint implants were studied. Sixteen sections of unimplanted and 14 sections of retrieved implants were analyzed with standard thermal analysis techniques. Results show that implantation does not alter the viscoelastic properties of Silastic HP-100 elastomers. The authors conclude that fracture of Silastic HP-100 implants cannot be attributed to changes in rheologic properties of the implanted elastomer.     

Pathology and pathogenesis of mucoviscidosis (author''s transl)

The section of the cat's mesotympanum, denuded of mucosa, to Silastic and gelatin film was studied and compared with the contralateral control ear, which was also denuded of mucosa. The ears were studied by horizontal pathological sections taken one, two, four, and six months post-lympanotomy and insertion of either gelatin film or Silastic. The Silastic, gelatin film and control ears were compared for inflammatory reaction, amount of fibrosis, and the quality and quantity of mucosal regeneration. The inflammatory reaction was increased in the ears with Silastic compared with their corresponding control ears or to the ears with gelatin film. The amount of fibrosis and the quality and quantity of mucosal regeneration was essentially the same in the Silastic, gelatin film, and control ears. This study shows that both substances are well tolerated in the middle ear and that neither substance stimulated or inhibited the regrowth of mucosa or fibrous tissue when compared with the control.     

Deep ocular socket reconstruction

A technique to reconstruct totally contracted sockets forms spacious, deep ocular fornices to accommodate ocular prostheses. Fixation of the midperiphery of mucous-membrane-lined, custommade conformers to the superior and inferior orbital rims secures the posterior periphery of the conformer deep in the orbit. The method restores the normal anatomy of the ocular fornices that not only extends to the orbital rims but also penetrates deeply into the orbit along its roof and floor. The procedure contrasts with conventional, frequently unsuccessful methods of socket reconstruction that form fornices only to the superior and inferior orbital rims without extending posteriorly into the orbit. Using this technique, we reconstructed deep, spacious sockets in five patients with serious socket contracture, allowing the patients to retain cosmetically acceptable artificial eyes. The principles advocated apply to all contracted sockets.     

An orbital roof fracture causing diplopia

Fractures of the orbital floor are frequently accompanied by diplopia. There are other bony injuries that may produce similar symptoms; however, these are rare. We will describe a case in which a fracture of the roof of the orbit, essentially involving the anterior cranial fossa, produced entrapment with diplopia. A six-month follow-up demonstrated excellent surgical and functional results.     

A case of orbital mesenchymal chondrosarcoma

A 22-year-old male presented with proptosis of his right eye of one month's duration. No abnormalities were present regarding visual acuity, ocular motility, or fundus findings. Systemic examinations gave negative results. An orbital tumor, 25 mm in size, was detected by computed tomography and magnetic resonance imaging in the affected side. The tumor was located nasal-posterior to the eyeball and appeared to be in apposition with the orbital floor. The tumor was removed through a maxillary sinus approach. Histopathological studies led to the diagnosis of extraskeletal mesenchymal chondrosarcoma. To the best of our knowledge, this is only the fifth case reported in Japan of mesenchymal chondrosarcoma. Originating in the orbit.     

Reconstruction of total maxillectomy defects with preservation of the orbital contents

Reconstruction after total maxillectomy with preservation of the orbital contents is technically more challenging than when the maxillectomy is combined with orbital exenteration. Reconstruction of such defects should (1) provide support to the orbital contents, (2) obliterate any communication between the orbit and nasopharynx, (3) reconstruct the palatal surface, and (4) achieve facial symmetry and a good aesthetic result. We report our experience in performing reconstructive surgery on 14 patients who had a total maxillectomy and preservation of the orbital contents using nonvascularized bone grafts for reconstruction of the orbital floor and maxilla, in conjunction with a soft-tissue free flap or pedicled muscle flap. The orbital floor was reconstructed using split ribs in six cases (42.9 percent), split calvaria in six cases (42.9 percent), and iliac crest graft in two cases (14.3 percent). A myocutaneous rectus abdominis free flap was used for soft-tissue reconstruction and resurfacing of the palatal mucosa in twelve patients (85.7 percent), and a temporalis muscle transposition was used in two elderly patients (14.3 percent). One patient died 2 days after surgery. Mean follow-up and aesthetic and functional results were assessed in the remaining 13 patients a minimum of 6 months postoperatively. In 9 of these 13 patients (69.2 percent), postoperative radiotherapy was administered. No reexplorations or free flap failures were observed. One rectus flap developed partial necrosis of the skin island intraorally without affecting the final result. All patients had adequate functional vision. One patient had a mild vertical dystopia; there were no cases of enophthalmos. Ectropion was the most common undesirable result and was present in 10 of 13 cases (76.9 percent). It was graded as mild in four cases (40.0 percent), moderate in four cases (40.0 percent), and severe in the remaining two cases (20.0 percent). Speech was considered normal in six cases (46.2 percent), near normal in six cases (46.2 percent), and intelligible in one case (7.7 percent). Chewing function was considered good (soft to unrestricted diet) in all cases except for one patient who was only able to eat a pureed diet. Aesthetic results after immediate reconstruction were considered good in nine cases (69.2 percent) and fair in four cases (30.8 percent). Primary reconstruction of total maxillectomy defects with orbital content preservation remains a complex problem without a perfect solution. The combination of nonvascularized bone grafts for orbital/maxillary reconstruction with a soft-tissue free flap is a safe, reliable, and effective method of maximizing postoperative functional and aesthetic results.     

Subtle diagnostic markers of orbital floor blow-out fracture on coronal CT scan

The sagittal plane, computerized tomography (CT) scan has been proposed as the most important radiological view in the diagnosis of orbital floor blow-out fractures. This view however is impractical and unnecessary. Direct, coronal plane CT scan with careful attention paid to the shape of the inferior rectus muscle and antral roof will successfully diagnose this traumatic condition, as in our reported case in which no other radiological abnormalities were present.     

Endolymphatic subarachnoid shunt failure caused by Silastic allergy

During the period from 1964 through 1994, the endolymphatic subarachnoid shunt operation was initially successful in eliminating endolymphatic hydrops and the symptoms and findings it produces in 76% of 645 ears of patients with Meniere's disease. After initial success, lasting from five weeks to nine years, endolymphatic hydrops suddenly returned due to obstruction of the Silastic shunt tube in 11% of patients. In these cases, prompt revision can often restore an initial good result. Histologic and immunologic examination of the material surrounding and occluding the tubes showed an allergic response to the Silastic material in most instances. Efforts to eliminate this cause of failure using a tube of new design and different plastic material are described.     

Vasectomy and vasovasostomy. II. A comparison of two methods of vasovasostomy: silastic versus chromic stents

Twelve adult, bilaterally vasectomized dogs were used to compare two different procedures for reuniting the severed vas deferens. Approximately 5 months postvasectomy six dogs had vasovasostomies utilizing Silastic stents and the vasa deferentia of six additional dogs were rejoined with intravasal chromic stents. Ejaculates were subsequently obtained at 2-week intervals and evaluated for sperm count, motility, viability, and seminal ion concentrations. All of the dogs in which Silastic had been utilized as the stent had sperm reappear in the ejaculate, whereas only 40% of the dogs in which chromic catgut had been utilized had reappearance of spermatozoa. The over-all quality of the ejaculate was also better in the animals in which Silastic had been utilized. Testicular and epididymal histology was normal in most dogs of both groups, but three of the dogs with chromic stents in which the anastomosis had not been a success had abnormal histology, with reduced numbers of spermatocytes, spermatids, and spermatozoa. The data suggest that Silastic stents are better than chromic stents for vas reanastomosis. They also suggest that some dog testes react negatively to vasectomy and do not recover by 1 year postvasectomy when vas patency is not reversed.     

Clinical and laboratory experience with heparin-impregnated silicone shunts for carotid endarterectomy

Our experience with use of a Silastic shunt for carotid endarterectomy is reviewed briefly, and the complication of shunt thrombosis despite intraoperative administration of heparin is noted. Of obvious importance are the reduction of blood flow and the possibility of embolization caused by accumulating thrombus. Shunt thrombosis has been abolished by the use of heparin-impregnated Silastic shunts. In experiments in dogs, such heparin-treated shunts showed greater thromboresistance than did untreated shunts.     

Eye movement in amyotrophic lateral sclerosis: a longitudinal study

Conservative therapy in cases of severe dysthyroid ophthalmopathy (DO) has not given satisfactory results. Since 1986, 51 patients (99 orbits) with marked DO have been treated by surgical decompression of the orbits. The procedure begins within the upper eyelid. The excision of the excessive skin and subcutaneous tissue is performed and eyelid fat is removed. In order to obtain the correction of the upper eyelid retraction, the levator aponeurosis is divided by 2-3 transverse incisions in its central part and Muller's muscle is sectioned at the level of its tarsal insertion. Through an incision in the lower eyelid, the posterior part of the orbital floor, the lateral orbit wall, as well as the periorbital and intraorbital fat are removed. Through an incision made over the medial margin of the orbit, the ethmoidal part of the medial orbital wall and the retrobulbar fat are removed. The periorbital periosteum should be incised at several sites. After operation all patients showed a significant reduction of exophthalmos (5-11 mm, 7.16 mm on average), significant reduction of intraocular pressure, marked improvement in ocular muscle function, as well as considerable reduction or disappearance of subjective symptoms. There was an improvement in vision in 68% patients who had impaired vision before the operation. There were no cases of subsequent impairment of vision or ocular motility. Mild relapse was recorded in three cases only and only one patient required unilateral reoperation. Strabismus surgery had to be performed in five patients due to unsatisfactory correction of double vision. It can be concluded that this method of orbital decompression gives very good functional and aesthetical long-term results.     

Mandibular erosion from silastic implants: evaluation with a dental CT software program

Silastic implants used to augment the chin during cosmetic surgery may cause erosive bone changes and complications. We describe the radiologic appearance of these changes and the dental CT reformatting programs by which they may be assessed. Multiplanar CT scans of four patients with Silastic chin implants were evaluated retrospectively for implant density, presence and size of bone defects, relationship of defects to root apices, relationship of defects to mental foramen, and associated findings. The dental CT software program was instrumental in delineating the relationship between the bone defects and the root apices.