Cheeklift With and Without Posterior Lamellar Spacer Grafts for Treatment of Lower Eyelid Retraction.

BACKGROUND: To compare outcomes of lower eyelid retraction repair using a subperiosteal midface lifting technique with and without posterior lamellar grafts. METHODS: Charts of patients undergoing a sub-periosteal midface lift for treatment of lower eyelid retraction using 4 techniques for posterior lamellar reconstruction were reviewed. Thirty patients were included in each of the groups: midface with hard palate graft (HPG), midface lift with acellular cadaveric graft (ADG), midface lift with retractor disinsertion (RD) and midface lift alone (NG). Measurements of distance from pupil center to lower lid margin (MRD2) and from lateral limbus to lower lid margin (MRD2limbus) were taken from pre- and postoperative photographs and compared. Secondary outcomes included rates of reoperation, major and minor complications, resolution of symptoms and keratopathy. RESULTS: One hundred twenty operations were assessed (n = 30 for each surgical group). The average follow-up time was 20 weeks. The median MRD2 elevation was 0.95 mm (NG), 0.85 mm (HPG), 1.59 mm (ADG) and 1.02 mm (RD). The median MRD2limbus elevation was 1.06 mm (NG), 0.92 mm (HPG), 1.45 mm (ADG) and 1.12 mm (RD). There were no significant differences in MRD2 or MRD2limbus between the 4 groups (p = 0.06 and 0.29, respectively). Reoperation rates were highest with in the hard palate graft group (33%) compared to other techniques (p = 0.0006). CONCLUSIONS: Similar degrees of lower eyelid elevation were achieved with all the midface lifting techniques, and complication rates did not significantly differ between techniques. However, the higher reoperation rates with the use of spacer grafts suggest that a no-graft technique may be preferable. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Conjunctival Müllerectomy With or Without Tarsectomy Using Absorbable Versus Nonabsorbable Suture.

PURPOSE: To compare the outcomes of blepharoptosis repair using conjunctival Müllerectomy with or without tarsectomy (CM±T) using absorbable suture versus nonabsorbable suture. METHODS: Retrospective case-series of all consecutive cases of CM±T ptosis repair between January 1, 2019, and August 31, 2021. Patients were placed in groups based on whether they had absorbable or nonabsorbable suture used during their procedure. Preoperative and postoperative measurements of MRD1 were gathered in both groups, and information on patient satisfaction, symmetry, complications, and reoperations. RESULTS: Ninety-two patients had surgery using nonabsorbable suture and 96 patients had surgery using absorbable suture, with average age of 72.0 and 70.9 years, respectively ( p = 0.488). When comparing nonabsorbable to absorbable suture, the groups did not differ on average preoperative MRD1 (1.11 mm [±0.96] vs. 0.96 mm [±0.86]; p = 0.161), average postoperative MRD1 (3.18 mm [±0.54] vs. 3.20 mm (±0.51); p = 0.736) or average MRD1 improvement (2.09 mm (±0.86) vs. 2.25 mm (±0.79); p = 0.089). Goal MRD1 was achieved in 85.3% of nonabsorbable cases and 82.8% of absorbable cases ( p = 0.562) and the rate of reoperation between groups was not significant ( p = 0.63). Good postoperative symmetry was noted in 91.6% of nonabsorbable and 91.0% absorbable suture cases ( p = 0.83). No difference in the number of complications was noted between groups ( p = 0.88), including need for contact lens placement (2.7% nonabsorbable, 1.3% absorbable; p = 0.37). CONCLUSIONS: The use of absorbable suture was found to have predictable and effective outcomes similar to cases using nonabsorbable suture for CM±T without an increase in complications or rate or reoperation.

Biplanar-pivoted V-Y Flap for Reconstruction of Medial Canthal Defects.

PURPOSE: To determine the safety and effectiveness of a biplanar-pivoted V-Y flap design in reconstructing medial canthal defects of all sizes. METHODS: Retrospective review of patients who underwent repair of medial canthal region defects with the biplanar-pivoted V-Y flap from January 2016 to May 2021. Variables collected included age, gender, surgical indication, defect sizes and location, flap(s) and/or graft(s) used, and follow-up time. Outcome measures included complications, patient satisfaction with cosmesis, ability to close the defect with minimal wound tension, and additional surgeries. RESULTS: Eighteen cases of medial canthal, nasal sidewall, and nasojugal fold area reconstruction were performed using a biplanar-pivoted V-Y flap in 18 patients. The cohort included 7 males and 11 females with a mean age of 72.4 years (range, 52-92 years) and mean follow-up time of 4.4 months (range, 1-14 months). Mean defect size was 2.0 × 1.4 cm (range, 0.5-5.5 cm). Eight patients received concomitant full-thickness skin grafts, five patients underwent simultaneous rotational flap repair, one patient underwent simultaneous nasoglabellar myocutaneous flap repair, and one patient received a simultaneous traditional, nonbiplanar V-Y plasty of the upper eyelid. All defects were closed with no wound tension. No cases of infection, hemorrhage, or wound dehiscence occurred during follow-up. Complications included mild ectropion (2 patients) and mild tip necrosis (1 patient). No patients elected for reoperation. No trapdoor deformity was observed. No patients underwent reoperation for local tumor recurrence. CONCLUSIONS: The extended mobility of the biplanar-pivoted V-Y flap provides excellent closure of defects involving the medial canthal region with minimal surgical complications.

Unilateral Ptosis, Proptosis, and Orbital Myositis After Shingles Vaccination.

Vaccinations for shingles are recommended for most adults over 60 years of age and are typically well tolerated. The present case describes acute onset of unilateral ptosis, proptosis, and orbital myositis developing within days after administration of shingles vaccination. The episode resolved to baseline after 1 week of treatment with steroids. To the authors' knowledge, this is first reported case of orbital inflammation following shingles vaccination. Given the temporal relationship and rapid response to treatment, this may represent an autoimmune reaction to the shingles vaccine.

Dimensions, Function and Applications of the Auricular Muscle in Facial Plastic Surgery.

PURPOSE: To determine the dimensions and function of the auricular muscle and to consider applications of this muscle in facial plastic surgery. METHODS: Nonpreserved fresh frozen human cadaver dissections from the (HOSPITAL-Blinded) Body Donation program were dissected. The length and width of the superior auricular muscle were measured. One surgeon performed all dissections and measurements. RESULTS: A total of seven left and five right hemifaces were studied. The average central height of the superior auricular muscle was 4.7 cm, and an average width was 5.0 cm. There was no significant difference between the average values of the left versus the right hemiface measurements. The muscle originated in the fibers of the galea and temporal fascia and inserted into the conchal cartilage in each specimen. Engaging the muscle in its line of action yielded slight elevation of the forehead and prevented movement of the galea along the vertex of the scalp. CONCLUSIONS: The auricular muscle acts as an occipitofrontalis stabilizer and a weak brow elevator. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors - www.springer.com/00266 .

Longitudinal Changes in Adult Bony Orbital Volume.

PURPOSE: To our knowledge, no prior study has measured bony orbital volume in a group of subjects over time. This study evaluates longitudinal changes in bony orbital volume with age. METHODS: A search was created for patients with digitized CT imaging studies of the orbit at least 8 years apart. Charts with a history of prior head trauma, head and neck tumors, sinus disease, head surgery, elevated intracranial pressure, thyroid eye disease, or conditions that could affect bone metabolism were excluded. Three outcome measures were used: orbital volume, medial orbital wall length, and lateral orbital wall length. Categorical data were summarized with frequency (%); normally distributed continuous data are summarized with mean (standard deviation), and non-normally distributed data were summarized with median. Normality was verified with Shapiro-Wilk Test. Paired t-tests were used to analyze the differences in the 3 outcome variables. RESULTS: One hundred and eighty-two subjects, 91 males and 91 females, were included. The median time between CT scans was 9.4 years. Orbital volume was significantly larger at the second scan than the first (p < 0.001). The average difference in orbital volume was 0.91 ml, an increase of 4.1%. Lateral orbital length was significantly shorter in the second scan than in the first (p = 0.046) though the difference was only 0.4 mm. There was no statistically significant change in medial orbital wall length. CONCLUSIONS: Bony orbital volume increases in individuals with age. This increase in orbital volume occurs in the context of soft tissue changes to contribute to the aging appearance of the periorbital region.

Comparison of Orbital Volume in Young Versus Senescent Human Skulls.

PURPOSE: To compare bony orbital volumes in young skulls with those of older skulls to elucidate aging-associated changes of the orbit. METHODS: One hundred Caucasian male skulls from the Hamann-Todd collection of the Cleveland Museum of Natural History were studied. There were 50 young skulls (age range, 19-33 years) and 50 senescent skulls (age range, 79-96 years). Volcanic sand was used to fill each orbit in an identical fashion and weighed as a proxy for volume. Digital calipers were used to perform linear measurements of the orbit. The relationship between orbit measures and skull size was assessed using Pearson's correlations and 95% CI, and statistical models to compare age groups adjusted for skull size. RESULTS: The volume of the orbits (P < 0.001), the horizontal diameter of the orbit (P = 0.015), and the orbital depth (P < 0.001) were significantly larger in the senescent group of skulls after adjusting for skull surface area. No significant differences were found in the vertical diameters of the orbit between the 2 groups. Skull size did not statistically differ between the age groups. CONCLUSIONS: Increases in the depth and horizontal dimensions of the orbit lead to increasing bony orbital volume with increasing age. These changes in size and shape of the orbit with age may contribute to phenotypic changes of aging and may affect disease processes and management.

Temporal Fat Pad Volume in Patients With Thyroid Eye Disease.

PURPOSE: To determine whether thyroid eye disease (TED) is associated with a change in temporal fossa soft tissue volume. METHODS: CT imaging studies were selected from patients with TED considering orbital decompression surgery and from an age-matched group of controls presenting to the Emergency Department for nontraumatic conditions requiring CT imaging. Measurements of the temporal fossa fat pad and soft tissue thickness were used as a proxy for volume and were performed using the zygomaticotemporal suture as a reference point. Categorical variables were described using frequencies and percentages, while continuous variables were described using medians and standard deviations. Chi-square tests were used to assess the relationship between gender and age group, while t-tests were used to examine the relationship between continuous variables and age group. RESULTS: A total of 56 CT scans were evaluated, including scans from 28 patients with TED and 28 controls. The following measurements were found to be significantly larger in the TED population: left fat pad measured 5 mm above the zygomaticotemporal suture (p = 0.012), right fat pad measured 15 mm above the suture (p = 0.005), right soft tissue measured 15 mm above the suture (p = 0.026), left fat pad measured 15 mm above the suture (p = 0.006), and the left soft tissue measure 15 mm above the suture (p = 0.032). CONCLUSIONS: Thyroid eye disease is associated with an increase in temporal fossa fat pad and soft tissue volume. These findings suggest that TED disease may produce pan-facial changes rather than changes confined to the peri-orbital region.

Perioperative Prophylactic Antibiotics in 1,250 Orbital Surgeries.

PURPOSE: Intravenous antibiotic prophylaxis is used for many clean-contaminated surgeries or clean surgeries with an implant, but its value for clean orbital surgery has not been determined. This study investigated infection risks and adverse effects related to antibiotics in patients undergoing orbital surgery. METHODS: A prospective, nonrandomized comparative case series of all patients undergoing orbital surgery with participating surgeons between October 1, 2013, and March 1, 2015. Types of surgery, antibiotic regimens, corticosteroid use, antibiotic side effects, and surgical site infections (SSIs) were entered into an electronic database and subsequently analyzed. Cases in which patients received postoperative oral antibiotics were analyzed separately. RESULTS: Of 1,250 consecutive orbital surgeries, 1,225 met inclusion criteria. A total of 1208 patients were included in the primary analysis: 603 received no antibiotic prophylaxis (group A), and 605 received a single dose of intravenous antibiotic (group B). Five patients (0.42%) developed an SSI, 3 in group A and 2 in group B. The difference in SSI rates was not statistically significant between the 2 groups (p = 0.66). Antibiotic prophylaxis, alloplastic implants, paranasal sinus entry, and corticosteroid use were not associated with differences in SSI rates. All SSIs resolved on a single course of oral antibiotics; an implant was removed in 1 case. There were no complications associated with a single dose of intravenous prophylaxis. However, 12% of 17 patients (group C) who received 1 week of oral postoperative prophylactic antibiotics developed antibiotic-related complications (diarrhea, renal injury), yielding a number needed to harm of 8.5. CONCLUSIONS: In this large series, antibiotic prophylaxis does not appear to have reduced the already low incidence of SSI following orbital surgery. Given the detriments of systemic antibiotics, the rarity of infections related to orbital surgery, and the efficacy of treating such infections should they occur, patients undergoing orbital surgery should be educated to the early symptoms of postoperative infection and followed closely, but do not routinely require perioperative antibiotics.

Anatomic Variations of the Infraorbital Foramen in Caucasian Versus African American Skulls.

PURPOSE: The infraorbital foramen (IOF) represents a highly conserved structure but demonstrates morphologic variability. The purpose of this study is to describe the IOF location, size, and supernumerary foramina in an African American population and compare it with a Caucasian population. METHODS: Sixty African American and 60 Caucasian skulls from the Hamann-Todd collection of the Cleveland Museum of Natural History were studied. The primary outcome was the number of accessory IOF and measurements of the location, size, shape, and direction of each foramen. Pearson chi-square, t tests, Fisher exact test, and Wilcoxon rank sum tests were used to analyze the data. RESULTS: The African American population had a smaller vertical IOF diameter (mean = 2.81 mm) compared with the Caucasian population (mean = 3.08 mm) on the right side (p < 0.01). The distance from the IOF to the anterior nasal spine on the left side was greater in the African American population (mean = 33.93 mm) compared with the Caucasian population (Caucasian mean = 32.84 mm, p = 0.03). The distance from the IOF to the zygomaticomaxillary suture was significantly shorter in the African American population (mean = 11.85 mm) compared with the Caucasian population (mean = 13.21 mm) on the left side (p = 0.01). Accessory foramina were found in 13 Caucasian skulls (21.7%) and 6 African American skulls (10%; p = 0.08). Two distinct types of IOF existed in each population, one close to the main foramen and one within the sutura notha. CONCLUSIONS: The IOF is smaller and exits more laterally, with a lower proportion of accessory foramina in an African American population compared with a Caucasian population. Both groups exhibit 2 distinct types of IOF. These morphologic differences should be noted during surgeries and anesthetic planning to avoid neurovascular complications.

Age-related Changes in Globe Position.

PURPOSE: To longitudinally evaluate for changes in globe position as part of the natural aging process. METHODS: A Cleveland Clinic Foundation imaging database of all head imaging scans performed from 1995 to 2017 was used to identify adults with normal orbits undergoing imaging studies at least 20 years apart. A total of 100 patients (200 globes) who had CT or MRI scans were studied. Globe position was determined by measuring the distance from the anterior aspect of the cornea to the zygomaticofrontal processes baseline. Clinically significant changes in globe position were defined as changes of ≥2 mm posteriorly (enophthalmos) or anteriorly (exophthalmos). RESULTS: On average, globe projection decreased by 0.25 ± 2.3 and 0.26 ± 2.2 mm in the right and left eyes, respectively. Clinically significant enophthalmos with age was measured in 55 (27.5%) globes in 35 (35%) individuals, while clinically significant exophthalmos with age was measured in 43 (21.5%) globes in 26 (26%) individuals. The proportion of cases that developed enophthalmos, exophthalmos, or experienced no change were not significantly different from each other (p = 0.26). No patients developed clinically significant enophthalmos in one eye and exophthalmos in the other. CONCLUSIONS: Adults may develop clinically significant enophthalmos, exophthalmos, or no change in globe position over a 20-year period. This lack of uniform change in globe position with age impacts surgical considerations for treatment of the aging periocular region.

Dimensions and Morphologic Variability of the Retro-Orbicularis Oculi and Frontalis Muscle Fat Pad.

PURPOSE: To quantify the complete dimensions of the retro-orbicularis oculi fat (ROOF) pad and to determine its relationship to other fat compartments of the forehead. METHODS: The entire forehead of 14 hemifaces of seven fresh frozen human cadavers (four female, three male) was dissected in the subcutaneous and submuscular planes. For each plane, a ruler was placed at the facial midline, and images of the dissection plane were taken at 90° and 45°. Images were analyzed for vertical height, horizontal length, the distance to midline from the point of maximal height, and area for each hemiface of the ROOF and for the entire fat compartment contiguous with the ROOF. A two-tailed t test was conducted between ROOF and ROOF plus the extended fat plane across all measurements. A Wilcoxon nonparametric signed rank test was performed to determine equivalent fat distribution of the extended fat plane over each cadaver's respective eye. RESULTS: The deep fat originating from the ROOF consistently extended laterally and superiorly in each specimen, distinctly separated via septae from the deep central, deep lateral, and the deep temporal fat compartments. The color, composition, and distribution of this contiguous deep fat did not differ phenotypically from the traditional ROOF. The extended deep fat plane possessed an average vertical height of 3.09 ± 0.68 cm, average distance to midline from point of maximal height of 3.56 ± 0.53 cm, an average horizontal length of 5.37 ± 0.82 cm, and an average area of 13.40 ± 2.69 cm. The extended deep fat demonstrated a statistically significant increase in maximal height, length, and total area compared with the ROOF. A Wilcoxon nonparametric signed rank test was nonsignificant (α = 0.01) across all measurements, demonstrating that the extended fat plane was similarly distributed over each eye. CONCLUSIONS: A layer of deep fat originating from the traditionally defined ROOF extends superiorly and laterally beneath the frontalis muscle, separate from the deep lateral, deep central, and deep temporal fat pads. This is the first study to clearly demonstrate a contiguous superficial musculoaponeurotic system layer of fat extending under both the orbicularis oculi and frontalis muscles. This plane of fat is more appropriately described as the retro-orbicularis oculi and frontalis fat.

Collagenoma of the Eyelid.

The rare case of an eyelid lesion comprised of hamartomatous dermal collagen, known as a collagenoma, is presented. Collagenomas may be sporadically acquired, or inherited as part of numerous autosomal dominant syndromes. In the appropriate clinical context, their diagnosis should prompt a thorough review of systems, systemic examination, and inquiry into family history, to assess for underlying autosomal dominant syndromes. Recognition of collagenomas may thus allow diagnosis of inherited syndromes, allowing patients to obtain appropriate genetic counseling, as well as screening and treatment of associated systemic pathology.

Retrobulbar Injection for Hyaluronic Acid Gel Filler-Induced Blindness: A Review of Efficacy and Technique.

While blindness after hyaluronic acid gel filler injection occurs only very rarely, it represents a devastating complication for the patient and the surgeon. Retrobulbar injection with hyaluronidase is the only known potential means of reversing this adverse event. However, positive outcomes remain anecdotal. We have attempted to review the current literature regarding possible efficacy and detail the indications and technique to be utilized, if hyaluronidase retrobulbar injection is to be attempted. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Anatomical Description of Zygomatic Foramina in African American Skulls.

PURPOSE: The zygomaticofacial/temporal/orbital nerve is a terminal branch of the zygomatic nerve and exits the orbit through zygomatic foramina. The nomenclature in the literature varies with some studies identifying all 3 foramina on the malar surface of the zygoma, while others describe each along different aspects of the zygoma. In this study, foramen on the malar surface of the zygoma is termed zygomatic foramen, and the authors describe anatomical variations in the position and number of these foramina in an African American population. METHODS: Sixty-two African American skulls from the Hamann-Todd collection of the Cleveland Museum of Natural History were studied. The primary outcome was the number of zygomatic foramina on the malar surface of the zygomatic bone. Secondary outcomes included the location of foramina relative to the orbital rim and the frontozygomatic suture. Mean and standard deviation were used to describe measurements. Chi-squared and Wilcoxon signed rank tests were used to analyze measurements between left and right hemicrania. RESULTS: The average number of foramina was 1.98 ± 0.93. More foramina were found on the right (2.13 ± 0.98) when compared with the left (1.68 ± 0.79; p = 0.001). The average distance between the lateral-most and medial-most foramina was 9.7 ± 5.0 mm. The distance from the orbital rim to the lateral foramen was 8.4 ± 4.2 mm, and distance from the orbital rim to the medial foramen was 7.7 ± 2.1 mm. The frontozygomatic suture was 22.9 ± 3.9 mm from the lateral foramen and 27.9 ± 3.6 mm from the medial foramen. CONCLUSION: The locations of the foramina in relation to the frontozygomatic suture and orbital rim were consistent with other populations. However, in this African American population, more zygomatic foramina were noted compared with previously published results in Korean, Indian, Brazilian, and West Anatolian populations. Surgeons should be cognizant of zygomatic foramina in this population to reduce potential neurovascular complications.

Microanatomical Location of Hyaluronic Acid Gel Following Injection of the Upper Lip Vermillion Border: Comparison of Needle and Microcannula Injection Technique.

PURPOSE: To compare needle and microcannula injection techniques in regards to the microanatomical location of hyaluronic acid (HA) gel injected in the upper lip vermillion border of cadaver specimens. METHODS: The upper lip vermillion border was injected transcutaneously with HA gel in 8 fresh hemifaces of 4 female human cadavers. Each hemiface was injected by a single experienced injector, the right side using a 27-gauge microcannula and the left side using a 30-gauge needle. A 2-cm region of each lip was excised lateral to a point 1-cm lateral to the philtrum. Specimens were fixed in 95% alcohol, embedded in paraffin, and stained with hematoxylin-eosin for histologic examination. RESULTS: Most HA injected with either a needle or a microcannula was located within the orbicularis oris muscle, and the remaining HA resided within the subcutaneous fat. In 3/4 right (microcannula) hemifaces, 100% of the HA was located within the muscle. Only 2/4 left (needle) hemifaces had at least 95% of the HA located within the muscle. Overall, in right (microcannula) hemifaces, 93% of the filler was located within the muscle, and in left (needle) hemifaces, 79% of the filler was located within the muscle (p =0.14). CONCLUSIONS: Most HA filler injected into the vermillion border after either microcannula or needle injection resides within the orbicularis oris muscle rather than in a subcutaneous/submucosal location. Injection with a microcannula shows a trend for more uniform intramuscular location compared with needle injection.

Paracanthal "One-Snip" Decompression in a Cadaver Model of Retrobulbar Hemorrhage.

PURPOSE: The authors assess the effectiveness of a modified paracanthal or "one-snip" procedure compared with the traditional lateral canthotomy and inferior cantholysis in the reduction of intraocular pressure (IOP) and proptosis in a human cadaveric model of retrobulbar hemorrhage. METHODS: This study comprised a comparative interventional study in a cadaveric model of retrobulbar hemorrhage. Six orbits of 3 fresh cadavers were included in the study. Baseline measurements of IOP and proptosis were recorded for all 6 orbits before and after simulation of retrobulbar hemorrhage as previously described. Right orbits (n = 3) underwent traditional lateral canthotomy and inferior cantholysis. Left orbits (n = 3) underwent modified paracanthal or "one-snip" procedure. The primary outcome measures were reduction in IOP and proptosis between the 2 techniques. RESULTS: Following lateral canthotomy and inferior cantholysis of each right orbit, the average IOP dropped to 14 mm Hg (range of 11-18 mm Hg), corresponding to a mean decrease of 32 mm Hg. Following the "one-snip" procedure of each left orbit, the average IOP dropped to 19 mm Hg with a range of 16 to 23 mm Hg, corresponding to a mean decrease of 22 mm Hg. There was no statistically significant difference in IOP reduction (p = 0.36) or proptosis reduction (p = 0.23) between the 2 treatment groups. CONCLUSIONS: Compared with traditional lateral canthotomy xand inferior cantholysis, the modified paracanthal or "one-snip" procedure is effective for IOP reduction and led to mild improvement of proptosis in a cadaveric model of retrobulbar hemorrhage. The authors hope this study helps improve orbital compartment syndrome outcomes by providing an option that more providers will feel comfortable performing and therefore decreasing time to surgical decompression.

Continuous Positive Airway Pressure Thresholds for Nasolacrimal Air Regurgitation in a Cadaveric Model.

PURPOSE: To elucidate the mechanisms underlying nasolacrimal air regurgitation (AR) in the setting of continuous positive airway pressure therapy. METHODS: Twelve nasolacrimal systems of 6 fresh female human cadavers were evaluated individually for AR using continuous positive airway pressure therapy before any nasolacrimal procedure. Cadavers were then randomly assigned to undergo nasolacrimal duct probing or endoscopic dacryocystorhinostomy and then each hemisystem was again evaluated for AR. The pressure where AR was first observed (discovery pressure) or maximum possible pressure in systems without AR was recorded. In systems that demonstrated AR, the pressure was then gradually decreased to the lowest pressure where regurgitation persisted. This pressure was recorded as the secondary threshold pressure. RESULTS: None of the 12 unoperated nasolacrimal systems or the 6 systems that underwent nasolacrimal duct probing demonstrated AR through the maximum continuous positive airway pressure therapy (30 cm H2O). After endoscopic dacryocystorhinostomy, all 6 nasolacrimal systems demonstrated AR. The mean discovery pressure was 16.0 cm H2O (range, 14.0-18.0 cm H2O) and mean secondary threshold pressure was 7.25 cm H2O (range, 6.5-8.0 cm H2O). CONCLUSIONS: Air regurgitation during continuous positive airway pressure therapy in the setting of prior endoscopic dacryocystorhinostomy can be replicated in a cadaver model. The secondary threshold pressures required for AR in this model were similar to AR pressures reported clinically. Prior to dacryocystorhinostomy, patients using continuous positive airway pressure therapy should be counseled on AR, and physicians should consider this phenomenon when evaluating ophthalmic complaints in postoperative patients on positive airway pressure therapy.

Deoxycholic Acid and the Marginal Mandibular Nerve: A Cadaver Study.

BACKGROUND: One of the rare but serious complications observed with deoxycholic acid administration is damage to the marginal mandibular nerve. In this study, we evaluated if deoxycholic acid directly induces histologic damage to fresh cadaveric marginal mandibular nerve. METHODS: A segment of marginal mandibular nerve was harvested from 12 hemifaces of 6 fresh cadavers. The nerve specimen was exposed to either 0.9% sterile saline for 24 h, deoxycholic acid (10 mg/ml) for 20 min, or deoxycholic acid (10 mg/ml) for 24 h. The nerve specimens were then fixed in glutaraldehyde for a minimum of 24 h. Toluidine blue stained sections were evaluated for stain intensity using light microscopy and color deconvolution image analysis. Supraplatysmal fat was harvested as a positive control and exposed to the same treatments as the marginal mandibular nerve specimens, then evaluated using transmission electron microscopy. RESULTS: Toluidine blue staining was less in the marginal mandibular nerve exposed to deoxycholic acid when compared to saline. The specimen exposed to deoxycholic acid for 24 h showed less toluidine blue staining than that of the nerve exposed to deoxycholic acid for 20 min. Transmission electron microscopy of submental fat exposed to deoxycholic acid revealed disruption of adipocyte cell membrane integrity and loss of cellular organelles when compared to specimens only exposed to saline. CONCLUSIONS: Deoxycholic acid (10 mg/ml) damages the marginal mandibular nerve myelin sheath in fresh human cadaver specimens. Direct deoxycholic acid neurotoxicity may cause marginal mandibular nerve injury clinically. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .