Jason Miller

Infant mandibular distraction with an internal curvilinear device.

Mandibular distraction has proven to be a valuable tool for lengthening the hypoplastic mandible and relieving airway obstruction in infants. Numerous devices have been developed to achieve the desired mandibular lengthening. Complications including poor vector control, need to mold regenerate, facial scarring, external pin loosening, and bulky hardware have been associated with previous devices. In an attempt to circumvent some of these problems, the senior author developed an internal curvilinear device (Osteomed Corporation, Dallas, TX), which is applicable to the infant mandible. The aim of this paper is to describe the use of this distractor as well as its indications and outcomes. Twelve micrognathic infants (ages range from 9 days to 8 months) who underwent mandibular distraction between March 2005-May 2006 at Lucile Packard Childrens Hospital were included in the study. Preoperative workup included an evaluation by a multidisciplinary team including a pediatric otolaryngologist, neonatal intensivist, pediatric pulmonologist, occupational therapist, and craniofacial surgeon. Pre and postoperative maxillomandibular discrepancy, sleep study, feeding evaluation, and three-dimensional computerized tomography scans were compared. All patients tolerated the distraction process well to completion without postoperative complication, except for one patient who had temporary facial nerve weakness, which resolved in 2 months. All patients with obstructive apnea had the obstructive component improved. The last six patients had pre and postoperative polysomnograms to document the improvement. Two patients with neurologic impairment had persistent central apnea. One nonsyndromic patient with inability to feed and feeding-related airway obstruction was taking complete oral feeds 2 weeks after distraction. Mandibular distraction with an internal curvilinear device is effective at relieving airway obstruction in micrognathic infants, while avoiding some previously reported complications.

Forecasting market prices in a supply chain game

Predicting the uncertain and dynamic future of market conditions on the supply chain, as reflected in prices, is an essential component of effective operational decision-making. We present and evaluate methods used by our agent, Deep Maize, to forecast market prices in the trading agent competition supply chain management game (TAC/SCM). We employ a variety of machine learning and representational techniques to exploit as many types of information as possible, integrating well-known methods in novel ways. We evaluate these techniques through controlled experiments as well as performance in both the main TAC/SCM tournament and supplementary Prediction Challenge. Our prediction methods demonstrate strong performance in controlled experiments and achieved the best overall score in the Prediction Challenge.

Prevention of tissue damage by water jet during cavitation

Cavitation bubbles accompany explosive vaporization of water following pulsed energy deposition in liquid media. Bubbles collapsing at the tip of a surgical endoprobe produce a powerful and damaging water jet propagating forward in the axial direction of the probe. We studied interaction of such jet with tissue using fast flash photography and modeled the flow dynamics using a two-dimensional Rayleigh-type hydrodynamic simulation. Maximal velocity of the jet generated at pulse energies of up to 1 mJ was about 80 m/s. The jet can produce tissue damage at a distance exceeding the radius of the cavitation bubble by a factor of 4. We demonstrate that formation of this flow and associated tissue damage can be prevented by application of the concave endoprobes that slow down the propagation of the back boundary of the bubble. Similar effect can be achieved by positioning an obstacle to the flow, such as a ring behind the tip.

Effect of the probe geometry on dynamics of cavitation

Cavitation bubbles accompany explosive evaporation of water after pulsed energy deposition during endosurgery. Bubbles collapsing at the time of an endo-probe produce a powerful and damaging water jet propagating forward in the axial direction of the probe. We demonstrate that formation of this flow and associated tissue damage can be prevented by application of the concave probes that slow the propagation of the back boundary of the bubble. A similar effect can be achieved by positioning an obstacle to the flow, such as a ring or a pick tip in a close proximity to the back, side or front of the tip. Dependence of the flow dynamics on geometry of the probe was studied using fast flash photography and particle velocimetry. With a flat tip a maximal jet velocity of 80 m/s is achieved at a pulse energy of 0.12 mJ, while with an optimized concave probe the jet is completely stopped. The maximal distance between the probe and the tissue at which cells were affected by the water jet was measured using choriallantoic membrane of a chick embryo and Propidium Iodide staining. Changing the tip geometry from flat or convex to an optimized concave shape resulted in reduction of the damage distance by a factor of 4 with pulse energies varying from 0.02 to 0.75 mJ. Elimination of the water jet dramatically improves precision and safety of the pulsed endosurgery reducing the axial damage zone to a size of the cavitation bubble at its maximal expansion.

Invited discussion: Surgical treatment of Treacher Collins syndrome.

The authors present their retrospective review of 50 patients operated on at the Hospital of Plastic Surgery in Polanica Zdroj between 1976 and 2005. They performed 258 total operations, for an average of 5.2 procedures per patient. Previously described techniques were used in the surgical management of these patients. These included mandibular distraction, palatoplasty, musculocutaneous eyelid flaps, dermal grafts, iliac crest bone grafts, chin osteotomies, auricular reconstruction, and nasal osteotomies. From their review, they conclude that a multidisciplinary approach is required, with emphasis on hearing impairment and occlusal disturbances. Methods other than nonvascularized bone grafts are also recommended to correct the orbitomalar tissue deficiency due to significant resorption. Typical craniofacial features of Treacher Collins syndrome (TCS) include a reduced cranial base angle (basilar kyphosis), mandibular hypoplasia with obtuse gonial angle and antegonial notching producing an angle class II malocclusion with anterior open bite, hypoplasia of the maxillary and zygomatic bones, and abnormalities of the middle-ear ossicles. Other features include lower-eyelid colobomas and eyelash deficiency, palpebral fissure anomaly with antimongoloid slant, external ear malformation, cleft palate, dorsal nasal hump, and variable soft tissue deficit of the midface. These combined features produce the typical facial features. Although expression of TCS is variable and each patient’s deformity unique, general guidelines for treatment are useful.

Curvilinear mandibular distraction in a patient with mandibulofacial dysostosis associated with Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) is a congenital erythroid aplasia or hypoplasia presenting in infancy as a macrocytic anemia. It has been linked to a gene defect resulting in the absence of specific ribosomal proteins that enable erythroid maturation. Treacher Collins syndrome is also associated with defective ribosomal biogenesis. Fifty percent of patients with DBA also present with additional physical abnormalities including growth delay, craniofacial abnormalities, upper limp abnormalities, cardiac defects, urogenital malformations, and cleft palate. Upper airway obstruction may be a complication from craniofacial disorders and may be responsible for life-threatening sleep apnea that may result in pneumonia or respiratory failure. This report is of a patient with DBA who presented at birth with respiratory distress secondary to tongue-based obstruction of the airway due to mandibulofacial dysostosis leading to need for intubation. In an effort to avoid a tracheostomy, the patient underwent bilateral internal mandibular osteodistraction on day 4 of life with a latency period of 0 days and a distraction at a rate of 2 mm/d for 10 days until a class 3 dental occlusion existed with 5 mm of overcorrection. In addition, the patient was born with choanal atresia that was repaired at day 30 of life. After completion of the mandibular distraction, the patient has avoided tracheostomy and is now 6 months of age. Recent polysomnogram has demonstrated no significant apnea or hypopnea.

Anterior Cranial Vault Distraction for the Treatment of Normocephalic Pancraniosynostosis.

Normocephalic pancraniosynostosis is a rare form of craniosynostosis that usually presents later in life secondary to a delayed onset of symptoms and the presence of a normal head shape. Since its initial description in the literature in 2010, normocephalic pancraniosynostosis remains a rare clinical entity that has only been reported in 6 patients. Surgical treatment in the 2 published reports has been by staged total calvarial reconstruction or anterior cranial vault remodeling with bilateral frontoorbital advancement. In this case report, the authors present 1 patient with normocephalic pancraniosynostosis and propose surgical treatment by anterior cranial vault expansion with distraction osteogenesis.

Unusual presentation of hemifacial microsomia

Hemifacial microsomia is a well known yet rare collection of developmental facial defects. Almost half of all known cases exhibit additional anomalies beyond the classic malformations of the first and second brachial arches. This case is unique in that it describes a child with hemifacial microsomia and an associated oropharyngeal stenosis, nasal stenosis and a v-shaped mandibular deformity.

Pulsed liquid microjet for intravascular injection

Occlusions of the retinal veins and arteries are associated with common diseases such as hypertension and arteriosclerosis and usually cause severe and irreversible loss of vision. Treatments for these vascular diseases have been unsatisfactory to date in part because of the difficulty of delivering thrombolytic drugs locally within the eye. In this article we describe a pulsed liquid microjet for minimally invasive intra-vascular drug delivery. The microjet is driven by a vapor bubble following an explosive evaporation of saline, produced by a microsecond-long electric discharge in front of the 25 micrometers electrode inside the micronozzle. Expansion of the transient vapor bubble produces a water jet with a diameter equal to the diameter of the nozzle, and with a velocity and duration that are controlled by the pulse energy. We found that fluid could be injected through the wall of a 60-micrometers -diameter artery in choriallantoic membrane using a 15-micrometers diameter liquid jet traveling at more than 60 m/s. Histological analysis of these arteries showed that the width of the perforation is limited to the diameter of the micronozzle, and the penetration depth of the jet is controlled by the discharge energy. The pulsed liquid microjet offers a promising technique for precise and needle-free intravascular delivery of thrombolytic drugs for localized treatment of retinal vascular occlusions.