Arun K. Gosain

To distract or not to distract: An algorithm for airway management in isolated Pierre Robin sequence

Approaches advocated for treatment of airway obstruction among neonates with Pierre Robin sequence include positioning, tongue-lip adhesion, mandibular distraction, and tracheostomy, with no established guidelines regarding which modality is appropriate for a specific patient. This report proposes an algorithm for the management of neonatal upper airway obstruction among patients with isolated Pierre Robin sequence. Data for 21 patients with isolated Pierre Robin sequence who were treated by one surgeon during a 9-year period were reviewed. Eighteen patients presented during the first 1 week of life and three patients presented late, between 12 and 33 months of age. Follow-up periods ranged from 9 to 70 months (median, 33 months). Successful airway management was achieved with positioning alone for 10 patients, with tongue-lip adhesion for seven of nine patients, with tracheostomy for two patients, and with mandibular distraction for three patients. Changes in the maxillary-mandibular discrepancy were significant with natural mandibular growth during the first 1 year of life (p < 0.0001). Oromotor studies performed 3 months or more after tongue-lip adhesion reversal (n = 9) demonstrated no appreciable deficits in tongue function, relative to other children with cleft lips/palates. A multidisciplinary team should evaluate all patients with isolated Pierre Robin sequence, to fully assess the maxillary-mandibular relationship, anatomically define the site of airway obstruction, and identify feeding difficulties. Patients should be evaluated for episodes of desaturation occurring spontaneously, during feeding, or during sleeping. Patients with desaturation should be further evaluated with double endoscopy (nasoendoscopy and bronchoscopy). If the airway obstruction is localized to the tongue base alone and cannot be controlled with positioning, then tongue-lip adhesion is the initial treatment of choice, because such patients demonstrate significant mandibular growth during the first 1 year of life. Mandibular distraction among neonates is reserved for failures of tongue-lip adhesion in which isolated tongue-base airway obstruction is documented. Neither of the patients who experienced failure of tongue-lip adhesion in this series would have been a candidate for distraction with the algorithm presented. Avoiding routine neonatal distraction serves to avoid facial scarring, nerve and tooth bud injury, and potential disturbances of intrinsic mandibular growth. Patients with persistent respiratory difficulties beyond age 9 months require reevaluation for multiple sites of airway obstruction. Mandibular distraction may be one of several modalities required to avoid tracheostomy for such patients.

Osteogenesis in calvarial defects: contribution of the dura, the pericranium, and the surrounding bone in adult versus infant animals.

Guided bone regeneration is a promising means for reconstructing bone defects in the cranium. The present study was performed to better define those factors that affect osteogenesis in the cranium. The authors studied a single animal model, investigating the contribution of the dura, the pericranium, and the adjacent calvarial bone in the process of calvarial regeneration in both mature and immature animals. Bilateral, 100-mm2, parietal calvariectomies were performed in immature (n = 16) and mature (n = 16) rabbits. Parietal defects were randomized to one of four groups depending on the differential blockade of the dura and/or the pericranium by expanded polytetrafluoroethylene membranes. Animals were humanely killed after 12 weeks, and histometric analysis was performed to quantitate the area of the original bone defect, new bone formation, and new bone density. Bone formation was quantified separately both at the periphery and in the center of the defects. Extrasite bone formation was also quantified both on the dural and on the pericranial sides of the barriers. Bone regeneration was incomplete in all groups over the 12-week study period, indicating that complete bone healing was not observed in any group. The dura was more osteogenic than the pericranium in mature and immature animals, as there was significantly more extrasite bone formed on the dural side in the double expanded polytetrafluoroethylene barrier groups. In both the dural and the double expanded polytetrafluoroethylene barrier groups, dural bone production was significantly greater in immature compared with mature animals. The dura appeared to be the source of central new bone, because dural blockade in the dural and double expanded polytetrafluoroethylene groups resulted in a significant decrease in central bone density in both mature and immature animals. Paradoxically, isolation of the pericranium in mature animals resulted in a significant reduction in total new bone area, whereas pericranial contact appeared to enhance peripheral new bone formation, with the control group having the greatest total new bone area. The present study establishes a model to quantitatively study the process of bone regeneration in calvarial defects and highlights differences in the contribution of the dura and pericranium to calvarial bone regeneration between infant and adult animals. On the basis of these findings, the authors propose that subsequent studies in which permeability of the expanded polytetrafluoroethylene membranes is altered to permit migration of osteoinductive proteins into the defect while blocking prolapse of adjacent soft tissues may help to make guided bone regeneration a realistic alternative for the repair of cranial defects.

Giant congenital nevi: A 20-year experience and an algorithm for their management

A variety of treatment options exists for the management of giant congenital nevi. Confusion over appropriate management is compounded because not all giant congenital nevi are pigmented, and malignant potential varies between different types. The present study sought to define factors in the presentation of giant congenital nevi that could provide an algorithm for their management, with respect to both the extent of resection and subsequent reconstructive options. A retrospective review of all patients who presented with a congenital nevus of 20 cm2 or greater since 1980 was performed, distinguishing among nevi involving the head and neck, the torso, and the extremities. Sixty‐one patients with giant congenital nevi were evaluated (newborn to age 16 years), of which 60 nevi in 55 patients have been operated on. Giant congenital nevi having malignant potential were pigmented nevi (53 patients) and nevus sebaceus (four patients). Those not having malignant potential were verrucous epidermal nevi (three patients) and a woolly hair nevus (one patient). Of the 60 giant congenital nevi operated on, expanded flaps were used in 25, expanded full‐thickness skin grafts were used in 10, split‐thickness or nonexpanded full‐thickness skin grafts were used in 13, and serial excision was used in 30. After 1989, operations tended to use multimodality treatment plans, with an increased use of expanded full‐thickness grafts and immediate serial tissue expansion. The use of serial excision, particularly in the extremities, also increased after 1989. Serial excision was the treatment of choice when it could be completed in two procedures or less, which occurred in more than 80 percent of cases using serial excision alone. Expanded flaps were the most common mode of reconstruction in the head and neck region and were used in 49 percent of these procedures. Serial excision was the most common form of treatment in the extremities, used in 50 percent of procedures. Tissue expansion in the extremities was infrequently used to provide an expanded flap (8 percent of procedures), whereas it was frequently used to provide expanded full‐thickness skin grafts harvested from the torso (used in 31 percent of procedures). On the basis of these data, algorithms for the extent of resection and subsequent reconstructive options for giant congenital nevi were developed. Their management should be formulated relative to pigmentation, malignant potential, and anatomic location of the respective lesions. (Plast. Reconstr. Surg. 108: 622, 2001.)

A dynamic analysis of changes in the nasolabial fold using magnetic resonance imaging : Implications for facial rejuvenation and facial animation surgery

&NA; An anatomic study was performed on living subjects using magnetic resonance imaging (MRI) to distinguish the relative contribution of skin, subcutaneous tissue, and muscle to dynamic changes in the nasolabial fold during facial animation and aging. MRI scans with the face in repose and then holding a full smile were performed in both young and old adult subjects. Anatomic landmarks were identified, and measurements characterizing their position were made on the MRI console. MRI resulted in excellent image resolution of facial tissue planes. Comparison between young and old subjects with the face in repose demonstrated that progressive thickening of the dependent portion of the cheek fat pad and overlying skin, with no appreciable change in the muscle plane comprising the levators of the upper lip, resulted in a deeper and more acute nasolabial fold in older subjects. In both age groups there was significant shortening of the mimetic muscles with smiling, with the lateral mimetic muscles drawn closer to the underlying facial bones. This was accompanied by redistribution of the cheek fat pad, thereby maintaining projection of surface landmarks within the cheek mass in young subjects with smiling. These findings indicate that in order to diminish the nasolabial fold, surgery for facial rejuvenation should be directed to the skin and subcutaneous tissue planes superficial to the mimetic muscles to the upper lip. In order to recreate a natural nasolabial fold during surgery for facial reanimation, contraction of the levator muscles to the upper lip should result in redistribution of the cheek fat pad without change in surface projection of the cheek mass or upper lip; this can only be accomplished if the reconstructed levator muscle is positioned deep to the cheek fat pad, with its insertion toward the deep (mucosal) surface of the upper lip.

A volumetric analysis of soft-tissue changes in the aging midface using high-resolution MRI: implications for facial rejuvenation.

Background: The present study evaluated volumetric changes in the aging midface. Both young and old living subjects were studied using high-resolution magnetic resonance imaging (MRI) to investigate the distribution and volume of the muscle and subcutaneous components of the midface. Methods: MRI with a customized radiofrequency coil was performed in 20 healthy Caucasian female volunteers equally divided between young (16 to 30 years) and old (>59 years) age groups. Sagittal oblique images were obtained at 1-mm intervals through the midface, perpendicular to the nasolabial fold. Quantitative analyses of the cheek fat pad overlying the levator labii superioris and zygomaticus major muscles were performed separately. Results: For both mimetic muscles, there were no significant differences between young and old subjects in muscle length, thickness, or volume from muscle origin to nasolabial fold. In addition, there were no significant differences between age groups in fatty infiltration of the muscles. The volumes of the medial and lateral aspects of the cheek fat pad were significantly greater in old than in young subjects (p < 0.05). In young subjects the greatest distribution of fat pad volume was found in the middle third of the cheek mass. There was a significant reduction in that portion of the fat pad distributed in the upper third and a further reduction in the lower third (p < 0.01). In old subjects, because of the increased distribution of fat in the upper third of the cheek fat pad, there was no significant difference in volume between the upper and middle thirds of the cheek fat pad. The percentage increase in fat in the upper third relative to the remainder of the midface was significantly greater in old compared with young subjects (p < 0.01). In contrast, the volume of the lower third of the midface was not significantly different between young and old subjects. Conclusions: The present study indicates that ptosis alone does not account for the changes observed in the aging midface. Selective hypertrophy of the upper portion of the cheek fat pad was also observed. The mimetic muscles, on the other hand, showed no significant differences with aging. To attain maximum precision in facial rejuvenation, these data suggest that after suspension of the ptotic cheek fat pad, each patient should be evaluated for excess bulk in the upper portion of the cheek fat pad. If excess bulk is present, patients may benefit further from selective reduction directed to the upper portion of the cheek fat pad, remaining superficial to the mimetic muscles of the face.

The nasolabial fold ; an anatomic and histologic reappraisal

The nasolabial fold was analyzed by anatomic and histologic evaluation of the tissue planes that create and surround the fold. A fascial-fatty layer exists in the superficial subdermal space extending from the upper lip across the nasolabial fold to the cheek mass. The SMAS is present in the upper lip as the superficial portion of the orbicularis oris muscle. Traction on the SMAS or periosteum lateral to the nasolabial fold can deepen the fold, while traction on the fascial-fatty layer lessens the fold. The fascial-fatty layer and skin of the cheek mass are suggested as the primary ptotic elements responsible for facial aging. (Plast. Reconstr. Surg. 93: 60, 1994.)

Giant congenital melanocytic nevi.

Background: Giant congenital melanocytic nevi are rare lesions with the potential to regress into malignant melanoma and/or neurocutaneous melanosis. Appropriate investigations include a screening magnetic resonance imaging scan, neurologic evaluation, and serial clinical observations looking for the development of these complications. Numerous excisional and nonexcisional options have been described for the management of giant congenital melanocytic nevi. Methods: A MEDLINE search was performed to obtain all relevant citations. Conclusions: To successfully treat these complex lesions, the plastic surgeon must understand the disease process, the natural history and complications, and the options for treatment.

Osteogenesis in cranial defects: Reassessment of the concept of critical size and the expression of TGF-β isoforms

Transforming growth factor-betas (TGF-&bgr;) have been demonstrated to be upregulated during osteoblast function in vitro and during cranial suture fusion in vivo. The authors hypothesized that spontaneous reossification of calvarial defects was also associated with upregulation of TGF-&bgr;. The present study was designed to (1) evaluate the concept of a critical-size defect within the calvaria in an adult guinea pig model and (2) investigate the association between the reossification of calvarial defects and TGF-&bgr; upregulation. Paired circular parietal defects with diameters of 3 and 5 mm and single parietal defects with diameters of 8 or 12 mm were made in 45 six-month-old skeletally mature guinea pigs. Three animals per defect size were killed after survival periods of 3 days, 1 week, 4 weeks, 8 weeks, or 12 weeks. New bone ingrowth was evaluated by assessing for linear closure by a traditional linear method and by a modified cross-sectional area method using an image analysis system in which the thickness of new bone was taken into account. Immunohistochemistry was performed using rabbit polyclonal antibodies to localize TGF-&bgr;1, -&bgr;2, and -&bgr;3. All specimens were photographed, and the intensity of immunostaining was graded based on subjective photographic assessment by three independent reviewers. No defect demonstrated any measurable bone replacement after a survival period of 3 days. All 3- and 5-mm defects were completely reossified after 12 weeks based on the linear analysis of new bone, indicating these defects to be less than critical size. However, new bone formation in the 5-mm defects never exceeded a mean of 40 percent by cross-sectional area of new bone. Percent of new bone formation by cross-sectional area was significantly higher within 3-mm defects than in all larger defects 4 weeks after the craniotomy, reaching a mean of 89 percent new bone by 12 weeks. Persistent gaps were noted on linear analysis of the 8- and 12-mm wounds by 12 weeks, and mean percent new bone by cross-sectional area remained below 30 percent. Immunolocalization demonstrated osteogenic fronts at the advancing bone edge and the endocranial side, in which the osteoblasts stained strongly for all isoforms of TGF-&bgr;. The intensity of osteoblast expression waned considerably after the majority of the defect had reossified. These data indicate that histometric analysis based on cross-sectional area more accurately reflects the osteogenic potential of a cranial defect than does linear inspection of defect closure. Although the interpretation of immunolocalization studies is highly subjective, independent assessment by three reviewers indicates that isoforms of TGF-&bgr; were upregulated during a limited “window” of time corresponding to the period of active calvarial reossification, and expression of TGF-&bgr; corresponded to osteoblast activity within osteogenic fronts. (Plast. Reconstr. Surg. 106: 360, 2000.)

Propranolol induces regression of hemangioma cells through HIF-1α-mediated inhibition of VEGF-A

Objective: To investigate the mechanism of propranolol on regression of infantile hemangiomas. Background: Propranolol has been found to be effective in treatment of severe hemangiomas of infancy. However, its mechanism of action is as yet unknown. Methods: Cultured proliferating and involuting hemangioma endothelial cells were treated with varying concentrations of propranolol for up to 4 days. Analysis was performed using cell viability, migration, and tubulogenesis assays, as well as quantitative RT-PCR and flow cytometry. Western blots and ELISA assays were used to assess protein expression. Results: Treatment with propranolol led to a dose dependent cytotoxic effect in hemangioma endothelial cells with decreased cell viability, migration, and tubulogenesis. This cytotoxic effect was VEGF (vascular endothelial growth factor) dependent, as demonstrated by decreased VEGF, VEGF-R1, and VEGF-R2 production. Decreased signaling through the VEGF pathway resulted in downregulation of PI3/Akt and p38/MAPK activity. Decreased VEGF activity was mediated through the hypoxia inducible factor (HIF)-1&agr; pathway but not through NF-&kgr;&bgr; signaling. Conclusions: Collectively, these data suggest that propranolol exerts its suppressive effects on hemangiomas through the HIF-1&agr;-VEGF-A angiogenesis axis, with effects mediated through the PI3/Akt and p38/MAPK pathways. These findings provide a plausible mechanism of action of propranolol on regression of infantile hemangiomas.

A CT scan technique for quantitative volumetric assessment of the mandible after distraction osteogenesis

Distraction osteogenesis has become an accepted method of treatment for patients requiring reconstruction of hypoplastic mandibles. We present a quantitative analysis of volumetric changes after distraction osteogenesis in a series of 10 patients. Group I (n = 5 patients, 3 unilateral craniofacial microsomia, 1 Goldenhaar syndrome, and 1 bilateral craniofacial microsomia) underwent unilateral distraction of the mandible. Group II (n = 5 patients, 1 Nager syndrome, 1 bilateral craniofacial microsomia, 1 developmental micrognathia, and 2 Treacher Collins syndrome) underwent bilateral distraction of the mandible. Predistraction and postdistraction axial and three-dimensional computed tomographic (CT) scans were digitized and transferred to a computer for analysis with image-processing software to determine the changes in volume of the mandible and bony regenerate. The CT-derived volume method was validated by scanning three dry cadaver mandible specimens and comparing the volume data with those derived from a water-displacement method. The difference between the two methods was less than 5 percent. The mean distracted length, as recorded from the calibrated device, was 22.6 mm in the 10 patients. In the unilateral distraction group, the mean increase in hemimandibular bone volume was 2.8 cc, with a mean percentage increase of 27 percent in the distracted hemimandible. In the bilaterally distracted patients, the mean increase in total mandibular volume was 7.9 cc, with a mean percentage increase in bone volume of 25 percent. This study represents the first attempt to quantify the increase in bone volume resulting from distraction osteogenesis. Quantitative volumetric analysis of CT scans is an accurate method to measure the amount of bone regenerate in patients undergoing distraction osteogenesis of the mandible or the extremities. The concept and utility of quantifying the volumetric changes in bone following distraction osteogenesis may become more important as multiplanar devices are developed and used in other areas of the craniofacial skeleton.