Reductions in home-range size and social interactions among dehorned black rhinoceroses (Diceros bicornis).

Poaching for horns and tusks is driving declines of megaherbivores worldwide, including the critically endangered African black rhinoceros (Diceros bicornis). By proactively dehorning entire rhinoceros populations, conservationists aim to deter poaching and prevent species loss. However, such conservation interventions may have hidden and underestimated effects on animals' behavior and ecology. Here, we combine >15 y of black rhino-monitoring data across 10 South African game reserves, comprising >24,000 sightings of 368 individuals, to determine the consequences of dehorning for black rhino space use and social interactions. While preventative dehorning at these reserves coincided with a nationwide decrease in black rhino mortality from poaching and did not infer increased natural mortality, dehorned black rhinos decreased their home range area by, on average, 11.7 km2 (45.5%) and were 37% less likely to engage in social encounters. We conclude that dehorning black rhinos as an antipoaching measure alters their behavioral ecology, although the potential population-level effects of these changes remain to be determined.

Group B streptococcal retropharyngeal cellulitis in a young infant: a case report and review of the literature.

The diagnosis of retropharyngeal cellulitis and abscess, although most common in children under 6 years of age, is often misdiagnosed in the newborn or early infancy period. The clinical signs of drooling, neck swelling, dysphagia, and torticollis may be absent or not easily identifiable. The following case report details a 2 1/2-month-old infant who presented with fever and irritability, and was subsequently diagnosed with group B streptococcal retropharyngeal cellulitis. Retropharyngeal cellulitis and abscess should be considered in the differential diagnosis of infants and young children who present with fever and irritability, particularly when lumbar puncture results are normal. This case also serves to highlight a rare manifestation of late-onset group B steptococcal disease.

A new design of a dorsal flap in the rat to study skin necrosis and its prevention.

BACKGROUND: The Mcfarlane flap or dorsal pedicled flap has become the standard model for pedicled rat skin flap study but its reliability has been called to question. In the past, there were possible confounding variable with the McFarlane flap and various methods were used to adjust these variables. We have developed a new model for studying skin flap necrosis and its prevention that eliminates these confounding variables. METHODS: The flap is a significant modification of the McFarlane flap where we form a blind ended pedicled tube using a 3 cm x 9 cm dorsal flap. Survival area is measured using digital photography and computer assisted analysis. This new flap is compared with the standard McFarlane flap with n=25 in each group. RESULTS: The mean survival area of the new flap (15.673 cm(2)+SD3.37) is comparable with the McFarlane flap (18.904 cm(2)+SD3.79). The relative merit lies in the elimination of the confounding variable of the graft bed influence on our flap without a significant reduction in the survival area. CONCLUSION: A new rat model is presented that may be used in studying the effect of various treatment modalities on pedicled skin flaps. This model has the benefit of eliminating graft bed effect without the risk of flap and wound infection or desiccation that have been encountered using other models. The new flap also has better demarcation of necrosis area in this study.

Functional anastomotic relationship between the supratrochlear and facial arteries: an anatomical study.

BACKGROUND: For the past 15 years, a forehead flap with its pedicle based at or below the medial canthus has been used without any flap loss. This study describes the anatomical vascular relationships allowing this flap design to be successful. METHODS: Nine fresh frozen cadaver heads were studied in three groups. Six heads were injected with red latex. In group I, the supraorbital, supratrochlear, and facial arteries of four heads were dissected out under the operating microscope. In group II, using two latex-injected heads, the median forehead flap was elevated in the extended fashion and the arteries within the flap were dissected. The distal portion of the flap was elevated supraperiosteally and the proximal portion was elevated subperiosteally. In group III, the arterial systems of three heads were injected with barium solution after the flaps had been elevated. Radiographic assessment was used to demonstrate the vascular pattern within the flap. RESULTS: Group I showed an anastomotic relationship between the supratrochlear and facial arteries and a consistent relationship between the infraorbital and facial arteries. Group II showed that the above-mentioned connections could be protected during the supraperiosteal and subperiosteal flap elevation. This was confirmed by radiographic assessment in group III. The vascular network of the flap was filled through the facial artery by means of the dorsal nasal and supratrochlear arteries. CONCLUSIONS: Within the paranasal and medial canthal region, there is an anastomotic relationship between the supratrochlear, infraorbital, and branches of the facial arteries, and branches from the contralateral side, creating a rich vascular arcade. This allows a median forehead flap to be narrowly based at the level of the medial canthus.

Repairing critical-sized rat calvarial defects with a periosteal cell-seeded small intestinal submucosal layer.

BACKGROUND: Small intestinal submucosa was evaluated as a bioscaffold candidate for periosteum-derived osteoblasts, and its suitability as a bone replacement material for cranial defects was investigated. METHODS: In the in vitro phase, osteoblasts were expanded in osteogenic medium and were then seeded onto small intestinal submucosa. To confirm osteoblast phenotype, they were tested for alkaline phosphatase, collagen type 1, and calcium expression. In the in vivo phase, calvarial critical-sized defects were created in 35 rats. The defects were either left untreated for surgical control (group 1), treated with small intestinal submucosa alone (group 2), treated with an osteoblast-embedded construct (group 3), or treated with an autogenous bone graft (group 4). The results were evaluated 12 weeks after surgery with radiopacity measurements and with stereologic analysis. RESULTS: Periosteal cells grew successfully in vitro. The percentage radiopaque area at the defect was measured to be 42, 74, 76, and 89 percent for groups 1, 2, 3, and 4, respectively. The pixel intensity of the same site was 36.4, 48.1, 47.5, and 54.5 for the same groups, respectively. Tissue-engineered constructs did not achieve enough bone formation and calcification to be effective as autogenous bone grafts and were not superior to the small intestinal submucosa alone. However, both small intestinal submucosa and cell-seeded small intestinal submucosa showed significantly more bone formation compared with the untreated group. CONCLUSIONS: Although it was demonstrated that the small intestinal submucosa itself has osteogenic properties, it was not significantly increased by adding periosteum-derived osteoblasts to it. The osteogenic properties of small intestinal submucosa are promising, and its role as a scaffold should be investigated further.

An alternative method for harvest and processing fat grafts: an in vitro study of cell viability and survival.

BACKGROUND: Adipocyte viability has been emphasized as essential for fat graft survival. There is no universal agreement on the methodology for handling fat grafts. OBJECTIVE: Two different methods of fat harvesting and techniques of tissue processing were compared by assessing cell viability, damage, and growth in vitro. METHOD: Fat was harvested from Zucker rats (n = 5) using (1) a 3-mm liposuction cannula with a 60-cc syringe (right side) or (2) a 2-mm blunt needle with a 10-cc syringe adapted to a fine-needle aspiration apparatus (left side). Tissues were then processed by decantation or cotton towel drying. Five samples for each of the four techniques were studied. Fat samples were processed for culture, and adipocytes and preadipocytes were plated in culture medium and expanded in vitro. Cell viability was assessed using cell counts, the MTT proliferation assay, G3PDH activity, and Oil Red O stain. RESULTS: Method 1 exerted significantly higher pressure (p = 0.009) than method 2 (643 +/- 2.5 versus 537 +/- 13.6 mm Hg). A larger oil layer was apparent with method 1 (1.11 +/- 0.29 g) than with method 2 (0.56 +/- 0.28 g). In addition, the highest number of viable preadipocytes was obtained using method 2B (p = 0.017). In culture, preadipocytes plated in 4F differentiation medium started to differentiate after 1 week, while those in Dulbecco's modified Eagle's medium/F12 with serum proliferated but did not differentiate. Mature adipocytes in adipogenic medium dedifferentiated and later redifferentiated into fat cells. CONCLUSIONS: Fat viability was better when fat was harvested by fine-needle aspiration. The plasticity of mature adipocytes and preadipocytes in vitro suggested that both might be involved in fat graft integration.

Age-dependent closure of bony defects after frontal orbital advancement.

BACKGROUND: The ability of the immature skull to spontaneously heal large bony defects created after craniofacial procedures was examined over a 25-year period of craniofacial surgery at the Children's Hospital of Philadelphia. METHODS: Only patients who underwent frontal orbital advancement and reconstruction, had at least 1 year of documented follow-up, and had the presence or absence of a bony defect documented on clinical examination were included. The sex, age at operation, diagnosis, history of a prior craniectomy, and presence or absence of a postoperative infection were determined for each patient. A variety of statistics were applied to the data. RESULTS: Eighty-one patients met the inclusion criteria. A statistically significant association between age at operation and closure of bony defect was demonstrated. Children who closed a bony defect after frontal orbital advancement and reconstruction were significantly younger than those children who had a persistent bony defect. Iterative regression analyses demonstrated that a transition point between closure and the inability to close bony defects occurred between 9 and 11 months of age. Closure of bony defects was not statistically associated with sex, prior craniectomy, an FGFR mutation, or a postoperative infection in the regression analysis. CONCLUSIONS: Healing of bony defects after frontal orbital advancement and reconstruction is significantly related to age at initial operation, with a mean age for closure of less than 12 months. Between 9 and 11 months of age, a change occurs that results in an increasingly lower probability of bony defect closure; thus, all other considerations being equal, initial frontal orbital advancement and reconstruction would ideally take place before this occurs.

Compartmentalization of massive vascular malformations.

A total of 18 patients with massive vascular malformations of the head and neck region were treated with compartmentalization using nonabsorbable sutures followed by injection of a sclerosant agent into each compartment. The indication for compartmentalization was either to stop potentially uncontrollable, life-threatening hemorrhage during the dissection of the lesion or to reduce its vascularity to allow a less dangerous subsequent resection. Compartmentalization was used in both high-flow and low-flow vascular malformations. In this technique, large nonabsorbable sutures are placed deeply in multiple areas within the lesion. The aim is to divide the malformation into multiple compartments by changing the direction of the suturing; in this way the sclerosing agent is provided with a more effective environment. The sclerosant used was either sodium tetradecyl sulfate 3%, absolute alcohol, or both. The total amount of infiltrate varied from 3 to 35 cc, according to the size of malformation. After compartmentalization, swelling was the most noticeable complication. With this technique, it was possible to treat what were considered untreatable malformations using standard techniques and to control the inevitable serious bleeding.

Cranial bone grafting for orbital reconstruction: is it still the best?

A variety of etiologies may result in functional and aesthetic deficiencies requiring orbital reconstruction. These are discussed, as are some of the possible repair techniques. In the current study, a randomized, retrospective chart review of one surgeon's experience with orbital reconstruction using cranial bone grafts was performed. The results of the chart reviews are presented, including preoperative diagnosis, clinical signs and symptoms, and postoperative findings. This study allowed a comparison and contrast to be made between exogenous materials and autogenous bone for orbital reconstruction. The differences between cranial and iliac bone as autogenous sources of reconstructive material were examined. The study indicates that cranial bone grafting for reconstruction of the orbit remains the material of choice.

Transphyseal bioabsorbable screws cause temporary growth retardation in rabbit femur.

A self-reinforced bioabsorbable poly-L-lactide/polyglycolide (SR-PLGA) 80/20 screw 2.0 mm in diameter was implanted transphyseally across the distal growth plate of the right femur in 24 immature rabbits. Radiologic evaluation revealed a mean shortening of 3.1 mm at 3 weeks, 11.1 mm at 6 weeks, 9.3 mm at 24 weeks, 9.0 mm at 48 weeks, and 12.6 mm at 72 weeks compared with the intact contralateral femur. In 13 control rabbits, drilling without screw placement did not cause any statistically significant femoral shortening. Therefore, the transphyseal SR-PLGA 80/20 screw caused growth retardation for 6 weeks postoperatively, after which the normal growth tendency was recovered until the growth plate was closed. The duration of temporary growth retardation correlated with that of strength retention of the SR-PLGA 80/20 copolymer. These findings suggest that SR-PLGA 80/20 screws can be applied in transphyseal bone fixation. The use of bioabsorbable screws for temporary epiphysiodesis seems attractive but requires further study.

Treatment of chronic frontal sinus disease with the galeal-frontalis flap: a long-term follow-up.

BACKGROUND: Management of benign chronic frontal sinus disease is difficult. Patients are frequently seen by multiple specialties for medical treatment and endonasal procedures before they seek or require definitive treatment with frontal sinus obliteration. The progression of the disease may lead to serious or life-threatening conditions such as local bone destruction, periorbital abscess, osteomyelitis, meningitis, cranial epidural abscess, or septicemia. This study presents the use of the galeal-frontalis myofascial flap as part of the treatment of this disease. METHODS: Thirty-one patients with chronic frontal sinus disease requiring obliteration were included in this study; all were approached through a coronal incision. The anterior wall of the frontal sinus was removed and the frontal sinus disease was evacuated. The sinus mucosa was completely removed, and the frontal sinus and nasofrontal duct were totally obliterated with either a unilateral flap or a bilateral galeal-frontalis flap. RESULTS: All patients had failed medical therapy and many had failed endonasal and endoscopic procedures. The mean follow-up was 43.6 months (range, 1 to 125 months). There were two early complications, a seroma and a hematoma. Sinus infection recurred in one patient 3 months postoperatively. The recurrent infection was treated in the same manner, using the available and viable galeal-frontalis flap to obliterate the frontal sinus, with no recurrence after 40 months. CONCLUSIONS: The galeal-frontalis flap has been investigated by angiography and is based on the supratrochlear and supraorbital vessels. Its location and vascularity make it reliable and effective for frontal sinus obliteration. In the head and neck area and elsewhere, filling defects with vascularized tissue prevents infection. A further advantage is that any residual defects are usually well tolerated by patients, and those requesting correction can be easily accommodated. The risks and complications from using exogenous materials and from performing secondary procedures for graft harvest are avoided. Considering that most patients presented with complications from advanced disease and that after one revision no patients have had recurrence of disease, obliterative treatment with the galeal-frontalis myofascial flap should be contemplated earlier in treating patients with chronic frontal sinus disease.

Management of frontal sinus fractures.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the radiographic and clinical diagnosis of frontal sinus fractures. 2. Identify various management approaches to the frontal sinus fracture and the indications for each. 3. Understand the rationale behind the decision of sinus obliteration when needed. 4. Recognize the most common complications arising from frontal sinus fracture treatment and the methods of avoiding or managing these complications. SUMMARY: Frontal sinus fracture management is still controversial and involves preserving function when feasible or obliterating the sinus and duct, depending on the fracture pattern. There is no single algorithm for the choice of management, but appropriate treatment depends on an accurate diagnosis using physical examination, computed tomography data, and the findings of intraoperative exploration. The amount and location of fixation and the need for frontonasal duct and sinus obliteration or elimination of the entire sinus depend on the anatomy of the fracture in general and the extent of involvement of the anterior wall of the sinus, the frontonasal duct, and the posterior wall in particular. This article discusses an algorithm for frontal sinus fractures that was obtained from the literature and modified according to the authors' experience. The decision-making process presented by the authors has withstood the test of time over a period of more than 20 years in their practice and has been proven to be safe and efficacious in treating frontal sinus fractures of all types.

Medial canthopexy: a proven technique.

The medial canthus comprises three limbs and functions to maintain the shape of the eye and to assist in drainage of the lacrimal sac. Repair of the medial canthal tendon is often complicated by canthal drift, extrusion of wires or sutures, and in-fracture of the contralateral orbital bones from pressure by transnasal wires. A technique used successfully for more than 25 years with a low rate of complications is described in a stepwise manner. The long-term outcomes of using this technique are reviewed. Thirty-three patient charts were reviewed. The mean age of patients was 22.4 years (range, 3 to 59 years). The surgical indications were trauma, neoplasm, and congenital deformity. Only 2 cases of canthal drift were noted after this procedure and were corrected with the same technique without recurrence. Traditional methods of medial canthopexy frequently result in complications; the technique described eliminates most if not all of these.

Vascular iliac crest with inner table of the ilium as an option in maxillary reconstruction.

Reconstruction of large maxillary defects has been a long-standing challenge to the reconstructive surgeon. Total maxillary reconstruction is desirable but often not possible; ideally, this would provide all the anatomical structural support, function, and esthetics missing because of the defect. A case is presented in which all the criteria for total maxillary reconstruction have been fulfilled. The patient is a 60-year-old man who had wide excision of his maxilla for ameloblastoma, followed by temporal bone flap reconstruction, which failed. He presented to our institution for further evaluation and possible treatment options; these were discussed with the patient and the multidisciplinary team that deals with congenital and acquired deformities in the head and neck area. An iliac crest free flap that included the inner table of the ilium based on the deep circumflex iliac artery was used for the reconstruction. The procedure is described, including restoration of a nasal lining. Osseointegrated implants were used for dental rehabilitation. Ameloblastoma is briefly discussed. The goals of maxillary rehabilitation and obstacles to obtaining those goals are presented. Options available for maxillary reconstruction are discussed, along with some of their advantages and disadvantages, as is the reason why the iliac crest free flap with the inner table of the ilium was chosen. An iliac crest free flap with microvascular anastomosis to facial vessels was used to reconstruct a large maxillary defect. Osseointegrated implants were used to facilitate dental rehabilitation. Our patient has excellent restoration of oronasal function with a satisfactory esthetic result.