Short-term condylar and glenoid fossa changes in infants with Pierre Robin sequence undergoing mandibular distraction osteogenesis.

The purpose was to evaluate short-term changes in condylar and glenoid fossa morphology in infants with Pierre Robin sequence (PRS) undergoing early (age <4 months) mandibular distraction osteogenesis (MDO) for the management of severe airway obstruction. Computed tomography data from infants with PRS who had MDO were compared to those of age-matched control infants without facial skeletal dysmorphology. Surface/volume, linear, and angular measurements of the condyle and glenoid fossa were obtained and compared between infants with PRS and controls. Eleven infants with PRS met the inclusion criteria. There were five female and six male subjects with a mean age at the time of MDO of 41±32 days. Prior to MDO, PRS mandibles had a smaller condylar articulating surface area and volume than age-matched control mandibles, with a more laterally positioned condylar axis (P≤0.05). Following MDO, there were significant increases in condylar articulating surface area and volume, approaching those of normal controls, with further lateral translation of the condylar axis (P≤0.05). Condyle and glenoid fossa morphology is largely normalized following early MDO in infants with PRS. The condylar axis translates laterally as a result of MDO; this change is not observed with mandibular growth in infants without PRS.

What are the defining characteristics of the most cited publications in orthognathic surgery?

The purpose of this study was to identify the characteristics associated with highly cited papers in orthognathic surgery. This was a cohort study of articles published in the English-language literature from 1900 to 2017. Citation databases were searched for papers related to orthognathic surgery and the most frequently cited papers were identified. For each paper, the following variables were collected: region of origin, time-period of publication, corresponding author specialty, journal of publication, topic area, study design, and number of citations. The outcome variable was the citation index (citations per year). North American investigators published 70% of the 100 most-cited articles in orthognathic surgery. The majority of papers were from oral and maxillofacial surgeons. Frequent content areas were diagnosis, virtual planning, fixation/stability, and complications. The majority (54%) of studies were cohort or case report/series. The mean number of citations was 235.0±126.5; the mean citation index was 9.9±6.1 citations per year. Time-period, content area, and study design were associated with the citation index (all P<0.001). Time-period, content area, and study design predicted the citation index (all P≤0.009). Among frequently cited papers in orthognathic surgery, oral and maxillofacial surgeons had the highest volume of contributions. Diagnosis, treatment planning, and complications were the most common topics studied.

The management of life-threatening haemorrhage following blunt facial trauma.

Life-threatening bleeding is uncommon following blunt facial trauma. There have been few reports in the literature describing its optimal management and a clear approach to treatment is yet to be defined. Reported strategies for control of facial haemorrhage include oro-nasal packing, external carotid artery ligation, transantral ligation of the internal maxillary artery, maxillary reduction and angiographic embolisation. Advances in angiography and selective vessel embolisation have made this the treatment of choice in cases of bleeding following penetrating facial injury. Its use in the management of bleeding following blunt facial trauma is unclear. The combined experience of the facial trauma teams at Harborview Hospital, Seattle, USA and Liverpool Hospital, Sydney, Australia yielded four cases of severe life-threatening haemorrhage following blunt trauma that underwent angiography. The roles of various management strategies were evaluated to generate a preferred management pathway in treating severe bleeding following blunt facial trauma.

Effect of isolation of periosteum and dura on the healing of rabbit calvarial inlay bone grafts.

Little is understood about the role of the recipient site in the revascularization and incorporation of autogenous inlay bone grafts in the craniofacial skeleton. Clinical experience demonstrates that secondary complex cranial vault reconstruction performed with scarred avascular dura or poor soft-tissue coverage may undergo significant resorption, thus compromising the aesthetic outcome. This study was designed to determine the effect of isolating autogenous orthotopic inlay calvarial bone grafts from the surrounding dura and/or periosteum on graft revascularization, healing, and volume maintenance in the adult rabbit. Adult rabbits were randomized into four groups (n = 10 per group); in each rabbit, the authors created a circular, 15-mm in diameter, full-thickness cranial defect followed by reconstruction with an autogenous calvarial bone graft, which was replaced orthotopically and held with microplate fixation. Silicone sheeting (0.5 mm thickness) was used to isolate the dura (group II), the periosteum (group II), or both dura and periosteum (group IV) from the graft interface. No silicone was placed in group I. Animals were killed 10 weeks postoperatively, and calvaria were harvested to assess graft surface area, morphology, quantitative histology, fluorochrome staining, and revascularization. Grafts isolated from both the dura and periosteum exhibited significant decreases in total bone (cortical and trabecular) surface area, blood vessel count, and interface healing compared with nonisolated control grafts. Isolation of either the dura or periosteum significantly (p < 0.05) decreased blood vessel count but had no significant effect on interface healing. Isolation of the dura alone was associated with a significant (p < 0.05) decrease in graft cross-sectional surface area and dural cortical thickness compared with nonisolated control grafts, but this effect was not observed when the periosteum alone was isolated. Quantitative histology performed 10 weeks after surgery indicated that graft isolation was associated with increased marrow fibrosis and necrosis compared with nonisolated controls; it also demonstrated evidence of increased activity in bone remodeling (osteoblast and osteocyte count, new trabecular bone, and surface resorption). Triple fluorochrome staining suggested increased bone turnover in the nonisolated grafts compared with isolated grafts at 1 and 5 weeks postoperatively. This study demonstrates that isolating a rabbit calvarial inlay autogenous bone graft from the dura and/or periosteum results in significantly (p < 0.05) decreased revascularization, interface healing, and cross-sectional areas of amount of mature bone compared with nonisolated control grafts 10 weeks after surgery. At this time point, histologic examination demonstrates a paradoxical increase in bone remodeling in isolated bone grafts compared with controls. It is possible that the inhibition of revascularization results in a delayed onset of the remodeling phase of graft incorporation. However, in the model studied, it is not known whether the quantitative histologic and morphometric parameters measured in these isolated grafts exhibit a "catch-up" phenomenon at time points beyond 10 weeks after surgery. The results of this study emphasize the importance of a healthy recipient site in the healing and incorporation of calvarial bone grafts but stress the need for further investigation at later time points.

Role and mechanism of PKC in ischemic preconditioning of pig skeletal muscle against infarction.

Protein kinase C (PKC) inhibitors, chelerythrine (Chel, 0.6 mg) and polymyxin B (Poly B, 1.0 mg), and PKC activators, phorbol 12-myristate 13-acetate (PMA, 0.05 mg) and 1-oleoyl-2-acetyl glycerol (OAG, 0.1 mg), were used as probes to investigate the role of PKC in mediation of ischemic preconditioning (IPC) of noncontracting pig latissimus dorsi (LD) muscles against infarction in vivo. These drugs were delivered to each LD muscle flap (8 x 12 cm) by 10 min of local intra-arterial infusion. It was observed that LD muscle flaps sustained 43 +/- 5% infarction when subjected to 4 h of global ischemia and 24 h of reperfusion. IPC with three cycles of 10 min ischemia-reperfusion reduced muscle infarction to 25 +/- 3% (P < 0.05). This anti-infarction effect of IPC was blocked by Chel (42 +/- 7%) and Poly B (37 +/- 2%) and mimicked by PMA (19 +/- 10%) and OAG (14 +/- 5%) treatments (P < 0.05), given 10 min before 4 h of ischemia. In addition, the ATP-sensitive K(+) (K(ATP)) channel antagonist sodium 5-hydroxydecanoate attenuated (P < 0.05) the anti-infarction effect of IPC (37 +/- 2%), PMA (44 +/- 17%), and OAG (46 +/- 9%). IPC, OAG, and Chel treatment alone did not affect mean arterial blood pressure or muscle blood flow assessed by 15-microm radioactive microspheres. Western blot analysis of muscle biopsies obtained before (baseline) and after IPC demonstrated seven cytosol-associated isoforms, with nPKCepsilon alone demonstrating progressive cytosol-to-membrane translocation within 10 min after the final ischemia period of IPC. Using differential fractionation, it was observed that nPKCepsilon translocated to a membrane compartment other than the sarcolemma and/or sarcoplasmic reticulum. Furthermore, IPC and preischemic OAG but not postischemic OAG treatment reduced (P < 0.05) muscle myeloperoxidase activity compared with time-matched ischemic controls during 16 h of reperfusion after 4 h of ischemia. Taken together, these observations indicate that PKC plays a central role in the anti-infarction effect of IPC in pig LD muscles, most likely through a PKC-K(ATP) channel-linked signal-transduction pathway.

Factors influencing use of digital prostheses in workers' compensation recipients.

The purposes of this study were to retrospectively identify factors associated with decreased use of digital prostheses in workers' compensation recipients 6 months after fitting and to identify characteristics of those individuals who requested and received a second set of prostheses after demonstrating consistent use of the first set. One hundred seventy-eight patients fitted with 281 digital prostheses completed a questionnaire 6 months after fitting. Forty-nine patients (28%) stated they never or occasionally used their prosthesis (low utilization) and 42 (24%) stated they used them more than 4 hours per day (high utilization). One hundred ten patients (62%) reported stump problems; 37 (21%) stated that the problem interfered with the use of the prosthesis. High utilization was associated with nonmanual employment after the injury. Low utilization was associated with male gender, stump problems, and a distal amputation level. Ring finger prostheses were least likely to be used; small finger prostheses, most likely. The country of origin of the patient was not associated with frequency of use. One hundred sixty-one patients had received the prostheses at least 3 years before the end of the study; 45% of these patients had requested and received a second set of prostheses. Women were more likely to request and receive a second set than men. We could not accurately predict future use of digital prostheses. Each case must be evaluated on an individual basis. (J Hand Surg 2000; 25A:80-85.

Straightening of aberrant carotid arteries with age in velocardiofacial syndrome.

Two cases of velocardiofacial syndrome demonstrated spontaneous straightening over a 4-year period of previously deviated carotid arteries on contrast enhanced computed tomography. Based on this finding, uncomplicated traditional pharyngeal flaps were performed on both patients. It is unknown whether straightening of aberrant vessels with age is the rule or the exception in this patient population.

Use of a fibrillar polylactic acid homopolymer in sheep cranial defects.

Guided tissue regeneration has been shown to permit osteoconduction in otherwise nonhealing cranial defects. The relative importance of preventing the prolapse of soft tissue versus the infiltration of individual connective tissue cells has not been determined. A fibrillar form of polylactic acid (PLA) was tested in 13-mm-diameter defects in the parietal bones of 12 sheep. The polymer was hypothesized to prevent the prolapse of dura and periosteum but allow entrance of individual cells. Control defects in the same sheep were either filled with autogenous bone shavings or left unfilled. The animals were killed at times ranging from 6 to 25 weeks and the defects examined grossly, radiologically, and histologically. The autogenous bone-filled defects were spanned by trabeculated bone by 6 weeks. The unfilled defects demonstrated prolapse of soft tissues into the defect; however, progressive centripetal bone growth was evident. The fibrillar PLA-filled defects were occupied by a full-thickness mixture of fibrous tissue interspersed with PLA. After 19 weeks, small "fingers" of bone were seen to minimally infiltrate the fibrous tissue. Although separation of the dura and periosteum was maintained by the fibrillar PLA, invasion of fibrous tissue restricted osteoconduction.