Measuring 3D facial displacement of increasing smile expressions.

BACKGROUND: Following paralysis, facial reanimation surgery can restore movement by nerve and/or muscle transfer within the face. The subtleties of lip and cheek movements during smiling are important aspects in assessing reanimation. This study quantifies average 3D movement vectors of the face during smiling based on the diverse Binghamton University 3D facial expression database to yield normative measures of lip and cheek movement. METHODS: The analysis was conducted on 100 subjects with 3D facial scans in a neutral and 4 increasing smile intensities, as well as associated labeled 3D landmark points. Each subject set of 3D scans was rigidly registered to measure average displacement vectors (distance, azimuth, and elevation) between the neutral and happy expressions. RESULTS: The average lip commissure displacement was found to be 9.2, 11.4, 13.5, and 16.0 mm for increasing smile levels 1-4, respectively. Similarly, the average commissure azimuth angle across all 4 smile levels is ∼44 ± 21 degrees, and the average elevation angle across all 4 smile levels is ∼37 ± 15 degrees. The maximum cheek displacement from the neutral expression was 4.5, 5.7, 6.8, and 7.9 mm for the smile levels 1-4, respectively. The average cheek movement azimuth angle is outward (increasing 1-13 degrees), and the elevation angle is upward (increasing 51-59 degrees) from the face. CONCLUSIONS: These data quantifying 3D lip and cheek smile displacements improve the understanding of facial movement and may be applicable to future assessment/planning of facial reanimation surgeries.

Sensitivity analysis of a validated subject-specific finite element model of the human craniofacial skeleton.

Developing a more complete understanding of the mechanical response of the craniofacial skeleton (CFS) to physiological loads is fundamental to improving treatment for traumatic injuries, reconstruction due to neoplasia, and deformities. Characterization of the biomechanics of the CFS is challenging due to its highly complex structure and heterogeneity, motivating the utilization of experimentally validated computational models. As such, the objective of this study was to develop, experimentally validate, and parametrically analyse a patient-specific finite element (FE) model of the CFS to elucidate a better understanding of the factors that are of intrinsic importance to the skeletal structural behaviour of the human CFS. An FE model of a cadaveric craniofacial skeleton was created from subject-specific computed tomography data. The model was validated based on bone strain measurements taken under simulated physiological-like loading through the masseter and temporalis muscles (which are responsible for the majority of craniofacial physiologic loading due to mastication). The baseline subject-specific model using locally defined cortical bone thicknesses produced the strongest correlation to the experimental data (r2 = 0.73). Large effects on strain patterns arising from small parametric changes in cortical thickness suggest that the very thin bony structures present in the CFS are crucial to characterizing the local load distribution in the CFS accurately.

Modeling and measuring average nasal asymmetry by dorsum midline and nose tip lateral deviation.

In rhinoplasty and nasal reconstruction, achieving symmetry is critical for optimal patient outcomes and reducing re-operation rates. Assessing nasal asymmetry is challenging, both pre- and intra-operatively, if based on only a surgeons' visual perception to assess and adjust the small distances important to cosmesis (<2-3 mm). To measure nasal symmetry, we first developed an algorithm to analyze lateral nasal deviation on facial three-dimensional (3D) scans captured by external surface scanning. In this, nasal deviation is measured by first registering a 3D facial scan to orthogonal axes in order to remove tilt. The lateral position of the nasal midline is then found across transverse planes along the dorsum and nasal tip regions by probing midpoints 1 and 2 mm back from the local maximum projection. The nasal deviation measurement algorithm was validated on a simulated asymmetrical nose model with known nasal deviation. Simulated deviations were applied to the symmetrical average nose using an exponential twist away from the face, with control of the maximum deviation and degree of curvature. Modeled deviations were evaluated with the algorithm at clinically negligible (0.02-0.06 mm) average differences and for small lateral deviations (1-5 mm). Nasal deviation using the algorithms was then measured for the 100 multi-ethnic subjects in the Binghamton University 3D Facial Expression database. Average values for maximum lateral deviation, deviation across the whole nose, and deviation at the nose tip were measured to provide context to deviation measurements in surgical planning. This research presents a new nasal assessment tool that can be useful in improving symmetry in rhinoplasty and reconstruction.

Fournier's gangrene with an unusual urologic etiology.

Fournier's gangrene is a necrotizing infection affecting the male genitalia and perineum, caused by synergistic aerobic and anaerobic organisms. We report on a previously undescribed upper urinary tract etiology for this life-threatening infection.

Use of a biomimetic strategy to engineer bone.

Engineering trabecular-like, three-dimensional bone tissue throughout biodegradable polymer scaffolds is a significant challenge. Using a novel processing technique, we have created a biodegradable scaffold with geometry similar to that of trabecular bone. When seeded with bone-marrow cells, new bone tissue, the geometry of which reflected that of the scaffold, was evident throughout the scaffold volume and to a depth of 10 mm. Preseeded scaffolds implanted in non-healing rabbit segmental bone defects allowed new functional bone formation and bony union to be achieved throughout the defects within 8 weeks. This marks the first report of successful three-dimensional bone-tissue engineering repair using autologous marrow cells without the use of supplementary growth factors. We attribute our success to the novel scaffold morphology.

The effect of infection and lag screw fixation on the union of membranous bone grafts in a rabbit model.

Infection complicating craniofacial procedures contributes significantly to patient morbidity and health care costs. The role of fixation materials in this setting remains unclear. As foreign material, does fixation hardware increase patients' susceptibility to developing postoperative infection? Furthermore, once infection is established, should fixation hardware be removed? To answer these questions, we performed an onlay membranous bone grafting procedure to the mandible in 94 New Zealand White rabbits, applied lag-screw fixation in half the animals, and inoculated the wounds with different bacterial doses. We quantified the differential rates of infection and rates of graft union in the presence of infection. The infection rates for the rigidly fixated group were not significantly different from the rates for the nonfixated group for a range of bacterial inoculum doses. There was no significant difference in the rates of resolution of infection and sepsis between the two groups. Gross and histologic assessments revealed a significantly lower union rate for infected grafts when compared with uninfected grafts. Furthermore, grafts rigidly fixated with a lag screw showed a higher rate of union when compared with nonfixated grafts in the presence of infection. In the absence of infection, the union rates for fixated and nonfixated groups did not differ significantly. While fixation hardware has been cited as a risk factor for postoperative infection, we were unable to show that lag-screw fixation contributes to this risk. Although infection impaired the union of membranous bone grafts to the recipient mandible, fixation of the grafts with a lag screw significantly decreased this deleterious effect of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of infection and lag screw fixation on revascularization and new bone deposition in membranous bone grafts in a rabbit model.

We have suggested that rigid fixation of membranous bone grafts in the presence of infection may improve graft-recipient bone union by facilitating graft revascularzation. To test this hypothesis, we grafted autogenous membranous bone grafts to the mandibles of 94 New Zealand White rabbits. Lag screw fixation was applied in half the animals. The wounds were inoculated with a range of Staphylococcus aureus doses. Infected and noninfected rabbits were injected weekly over a 5-week course with fluorescein bone markers and with a marker of vascular endothelium (procion red) just prior to sacrifice. Revascularization and new bone deposition in the grafts were then quantified histologically for the 75 rabbits available for data collection. Infection decreased the amount of graft revascularized and the amount of new bone deposited for both rigidly fixated and nonfixated grafts. Grafts fixated with a lag screw showed a greater amount of revascularization and new bone deposition in the presence and absence of infection when compared with nonfixated grafts, supporting the hypothesis that rigid fixation of membranous bone grafts in the presence of infection may promote graft survival and union by improving revascularization and osteogenesis within the graft.

A stereotactic system for guiding complex craniofacial reconstruction.

A stereotactic system has been designed to address the problem of achieving symmetry in complex and extensive craniofacial defects. Preliminary testing suggests that such a system, which allows for the intraoperative application of preoperative CT planning, will be useful in guiding the reconstruction of congenital or acquired bony time, is being used to investigate the correlation of intraoperative globe position following enophthalmos correction with long-term outcome, particularly as it relates to the size and location of the orbital defect, and the timing of the procedure.

High pressure injection injuries: an overview.

Injuries resulting from the use of high pressure injectors and spray guns are relatively rare; however, the potential tissue damage caused by the injury as well as the extent of the injury itself may go unrecognized by the primary physician. The purpose of this paper is to inform the emergency physician of the nature and standard management of this type of injury. A basic understanding of the pathophysiology of the high pressure injection injury (HPII) is essential in avoiding the mistakes in management that have been reported in the literature. The emergency management of the HPII includes: evaluation and immobilization, tetanus and antimicrobial prophylaxis, supportive and resuscitative measures, analgesia, and minimizing the time to definitive surgical treatment.

An optimized process flow for rapid segmentation of cortical bones of the craniofacial skeleton using the level-set method.

Accurate representation of skeletal structures is essential for quantifying structural integrity, for developing accurate models, for improving patient-specific implant design and in image-guided surgery applications. The complex morphology of thin cortical structures of the craniofacial skeleton (CFS) represents a significant challenge with respect to accurate bony segmentation. This technical study presents optimized processing steps to segment the three-dimensional (3D) geometry of thin cortical bone structures from CT images. In this procedure, anoisotropic filtering and a connected components scheme were utilized to isolate and enhance the internal boundaries between craniofacial cortical and trabecular bone. Subsequently, the shell-like nature of cortical bone was exploited using boundary-tracking level-set methods with optimized parameters determined from large-scale sensitivity analysis. The process was applied to clinical CT images acquired from two cadaveric CFSs. The accuracy of the automated segmentations was determined based on their volumetric concurrencies with visually optimized manual segmentations, without statistical appraisal. The full CFSs demonstrated volumetric concurrencies of 0.904 and 0.719; accuracy increased to concurrencies of 0.936 and 0.846 when considering only the maxillary region. The highly automated approach presented here is able to segment the cortical shell and trabecular boundaries of the CFS in clinical CT images. The results indicate that initial scan resolution and cortical-trabecular bone contrast may impact performance. Future application of these steps to larger data sets will enable the determination of the method's sensitivity to differences in image quality and CFS morphology.

Extramammary Paget disease: review of patients seen in a non-melanoma skin cancer clinic.

Extramammary Paget disease (EMPD) is a rare skin disease commonly found in the anogenital region. In this study, we aimed to identify EMPD patients seen in the non-melanoma skin cancer clinic at Odette Cancer Centre and to describe the treatments delivered and outcomes achieved. From 2000 to 2009, 14 patients were seen. Initial treatment recommendations included imiquimod and surgical excision, although half the patients required more than one treatment modality, highlighting the difficulty of achieving complete eradication of this disease.

Autosomal dominant craniometaphyseal dysplasia with atypical features.

Craniometaphyseal dysplasia (CMD) is a rare genetic disorder of bone modelling characterised by hyperostosis and sclerosis of the craniofacial bones, and abnormal modelling of the metaphyses. Clinically, autosomal dominant (AD) CMD is characterised by facial distortion and cranial-nerve compression. The goals of surgical treatment for AD CMD are cosmetic recontouring of the sclerotic craniofacial bones, correction of nasal obstruction and correction or prevention of neurological manifestations. We describe the successful correction of AD CMD craniofacial manifestations in an individual with atypical findings, and outline an approach for correcting the craniofacial deformities associated with this rare disorder.

Warmed local anesthetic reduces pain of infiltration.

The effect of warming local anesthetic on the amount of pain experienced during local infiltration was tested by comparing equal volumes of 40 degrees C- and 21 degrees C-infiltrates in each of 26 subjects. Six subjects were patients undergoing excision of two benign asymptomatic nevi in separate locations, and 20 subjects were healthy adult volunteers who were injected in bilateral antebrachial sites. The warmed and room temperature solutions were randomized to each side, so that each subject received both temperature injections in random order. All subjects and the injector were blinded. The rate of injection was time-controlled (0.05 ml/sec). Following both injections, subjects were asked to rate the pain experienced at each site. In addition, the subject was asked if there was no difference, a slight difference, or a substantial difference between the two sites. A two-tailed paired t-test was used to analyze the mean difference in pain scores for all subjects. Paired analysis of the pain scores for each subject eliminated intersubject variance of pain tolerance. The mean difference in pain score between the room temperature and warmed solutions was +1.5 (p < 0.0001). Of the 21 subjects (81%) who found the warmed solution less painful, 11 (52%) found the difference to be significant, while 10 (48%) found the difference to be slight. Two subjects (8%) found no difference between the two, while 3 subjects (11%) found the colder solution slightly less painful. We conclude that warming local anesthetic to 40 degrees C prior to subcutaneous injection is a simple, inexpensive means of reducing the pain of local infiltration.

The Langer-Giedion phenotype associated with a unique skeletal finding in a mentally retarded adolescent male. A case report.

A case of a mentally retarded male patient with associated physical abnormalities resembling the multiple exostoses-mental retardation syndrome (MEMR, Langer-Giedion or Ale-Calo syndrome) is reported. The patient represents one of the most severe examples of this condition; he also has a triphalangeal thumb with double distal phalanges, a feature not reported previously.

Reassessing the efficacy of the Dornier MFL-5000 lithotriptor.

PURPOSE: The Dornier MFL-5000* is a multifunctional lithotriptor unit that has been purported to be highly efficacious for treating stones. Our experience led us to believe that the actual success rates are not as high as those reported by others. We objectively reexamined the efficacy of this device and factors contributing to treatment success or failure. MATERIALS AND METHODS: We retrospectively reviewed the records and x-rays of 105 consecutive patients treated with extracorporeal shock wave lithotripsy (ESWL*) using the MFL-5000 during an 18-month period from September 1997 to March 1999. One patient was excluded from study due to a stone within a caliceal diverticulum. Patients were divided evenly by gender and stone laterality. In 70% of cases a stent was placed preoperatively to relieve obstruction and/or facilitate the passage of calculous fragments. The majority of stones (70%) were 10 mm. or less. Treatment success was determined by examining x-rays done preoperatively and at a median of 4 weeks postoperatively. RESULTS: ESWL was successful in only 47% of our patients, defined as residual stone fragments 2 mm. or less. A secondary procedure was required in 27% of the patients, including repeat ESWL in 6, ureteroscopic stone manipulation in 14, percutaneous tube placement in 1 and percutaneous nephrolithotripsy in 7. Factors contributing to secondary procedures and poor stone clearance were a stone burden of greater than 100 mm.2 and mid pole location (p = 0.0242 and 0.016, respectively). Poor stone fragmentation and clearance were noted despite significantly more shocks delivered (p = 0.0122). Only a small stone burden of 50 mm.2 or less responded well to ESWL (p = 0. 0142). CONCLUSIONS: These results compel us to reconsider the effectiveness of the Dornier MFL-5000 lithotriptor. We encourage groups at other institutions to reexamine and report their success rates. We recommend the use of this lithotriptor only for a stone burden of 50 mm.2 or less.

Is tube repair of aortic aneurysm followed by aneurysmal change in the common iliac arteries?

To address the concern that tube repair of an abdominal aortic aneurysm might be followed by aneurysmal change in the common iliac arteries, 23 patients who had undergone the operation were re-examined 3 to 5 years later. Although 9 had had minimal ectasia of these arteries preoperatively, in none of the 23 was there symptomatic or radiologic evidence of aneurysmal change on follow-up. Measurements of the maximum intraluminal diameters were made by computed tomography; they indicated no significant differences between the preoperative and follow-up sizes of the common iliac arteries. The variation in time to follow-up also showed no significant correlation with change in artery diameter.

Postoperative infections in craniofacial reconstructive procedures.

The rate of, and possible risk factors for, postoperative craniofacial infection is unclear. To investigate this problem, we reviewed 349 cases of craniofacial skeletal procedures performed from 1996 to 1999 at our institution. Infection rate was determined and correlated with the use of implants, operative site, and cause of deformity. The inclusion criteria consisted of all procedures requiring autologous or prosthetic implantation in craniofacial skeletal sites, as well as all procedures involving bone or cartilage resection, osteotomies, debridement, reduction and/or fixation. Procedures that did not involve bone or cartilage surgery were excluded. The criteria for diagnosis of infection included clinical confirmation and one or more of 1) intravenous or oral antibiotic treatment outside of the prophylactic surgical regimen; 2) surgical intervention for drainage, irrigation, and or debridement; and 3) microbiological confirmation. Among the 280 surgical cases that fit the inclusion criteria and had complete records, there were 23 cases of postoperative infection (8.2%). The most common site for postoperative infection was the mandible (infection rate = 16.7%). Multiple logistic regression analysis revealed gunshot wound to be the most significant predictor of postoperative infection. Additionally, porous polyethylene implantation through a transoral route was correlated with a significant risk of postoperative infection.