Septal fracture in Nautilus: implications for cephalopod paleobathymetry

Analysis of septal geometry, as embodied in the septal strength index model developed by Westermann (1973, Lethaia 6). , has become a prime avenue for estimating living depths of fossil cephalopods. We have examined the fracturing of Nautilus septa, and its bearing on strength index, by inducing septal rupture under the action of hydrostatic pressure. We found that: (1) septa which actually fail under pressure are not generally weakest as defined by their strength indices; (2) septal strength as defined by the strength index is not correlated with rupture pressure; and (3) most instances of septal failure originate in septal sutures, not in the septa. These results indicate that: (1) septal strength index does not yield wholly reliable strength or depth estimates; and (2) the shortcomings of the strength index model stem from its inability to account for complexities of mechanical failure in morphologically complex cephalopod shells.     

Combined conchal cartilage-ethmoid bone grafts in nasal surgery

Septal cartilage grafts are frequently required in rhinoplasties and nasal reconstructions. Unfortunately, sufficient septum is not always available for graft purposes. Conchal cartilage can serve as a substitute, but its usefulness is limited because of its soft, elastic nature. Applying thin sheets of pliable ethmoid bone to conchal cartilage gives the cartilage greater strength and, at the same time, allows it to retain some flexibility. This article examines the role of combined conchal cartilage-ethmoid bone grafts in nasal surgery. These grafts are simple to construct and are versatile in their application. By maintaining a free cartilage edge, they are readily sutured into place. The results seem to last long term.     

Nasal fracture management: minimizing secondary nasal deformities

Current management techniques for acute nasal fractures result in a high incidence of posttraumatic nasal deformity (14 to 50 percent). Associated traumatic edema, preexisting nasal deformity, and occult septal injury account for most of these acute reduction failures. Working with a detailed patient history and a physical examination that included rigid nasal endoscopy, the authors formulated a clinical algorithm for acute nasal fracture management, the use of which can reduce the incidence of posttraumatic nasal deformity. In this article, the authors review the literature, then discuss their management techniques over the past 11 years in 110 cases with a 9 percent nasal revision rate. This low incidence of revision is attributed to complete nasal assessment (bony and septum), use of outpatient controlled general anesthesia, and primary septal reconstruction in cases with severe septal fracture dislocation.     

A simple bone dust collector

A new instrument for harvesting craniotome bone dust is described. This has been designed with the contours of the skull in mind and the ideal bone fragment size for satisfactory graft take.     

Redefining the Septal L-Strut in Septal Surgery

In septal surgery, the surgeon preserves the L-strut, the portion anterior to a vertical line drawn from the rhinion to the anterior nasal spine (ANS) and at least a 1-cm width of the dorsal and caudal septal segment, to decrease the potential for loss of the tip and dorsal nasal support. However, nasal tip collapse and saddle deformities occur occasionally. We utilized a mechanical approach to determine the safe width size for the L-strut in contact with the maxillary crest. Five L-strut models were designed based on computed tomography data (80 patients) and previous studies (55 patients). All L-strut models connected the perpendicular plate of the ethmoid bone (PPE) and the maxillary crest and were assumed to be fixed to the PPE and maxillary crest. An approximated daily load was applied to the dorsal portion of the L-strut. Finite element analyses were performed to compare the stress, strain, and displacement distribution of all L-strut models. According to the differences in the contact area between the caudal L-strut and maxillary crest, there are significant differences in terms of the stress, strain, and displacement distribution in the L-strut. High stresses occurred at the inner corner of the L-strut when 60 - 100% of the strut was in contact with the maxillary crest. High stresses also occurred at the inferior portion of the caudal L-strut when 20 - 40% of the caudal strut was in contact with maxillary crest. We conclude that it is important to preserve the 1-cm width L-strut caudal segment, which corresponds to the portion posterior to a vertical line drawn from the rhinion to the ANS. In particular, we must maintain more than 40% of the contact area between the L-strut and the maxillary crest when the septal cartilage in the caudal portion of the L-strut is harvested.     

Cantilever nasal bone grafting with miniscrew fixation

A technique of rigid miniscrew fixation of cantilever nasal bone grafts is described. This produces stable, predictable nasal contour and tip projection without significant bone graft resorption.     

Bold螺钉治疗内踝骨折的疗效分析

目的：对比Bold螺钉和普通空心螺钉内固定治疗单纯内踝骨折的疗效。方法：空心螺钉治疗单纯内踝撕脱骨折57例,分为A组Bold螺钉内固定治疗内踝骨折25例,B组使用普通空心螺钉内固定32例。结果：两组57例均获得随访,两组病例远期均能得到较坚强的固定和良好的功能恢复,但Bold螺钉组相对普通螺钉组愈合时间更快（P〈0.05）,下床活动时间更早（P〈0.05）,早期踝关节功能评分高（P〈0.05）,但六个月后没有明显差异。结论：Bold螺钉内固定有助于内踝骨折早期愈合和早期功能锻炼,是一种比较好的内固定材料,值得推广。     

Bold 螺钉治疗内踝骨折的疗效分析

目的:对比Bold螺钉和普通空心螺钉内固定治疗单纯内踝骨折的疗效。方法:空心螺钉治疗单纯内踝撕脱骨折57例,分为A组Bold螺钉内固定治疗内踝骨折25例,B组使用普通空心螺钉内固定32例。结果:两组57例均获得随访,两组病例远期均能得到较坚强的固定和良好的功能恢复,但Bold螺钉组相对普通螺钉组愈合时间更快(P<0.05),下床活动时间更早(P<0.05),早期踝关节功能评分高(P<0.05),但六个月后没有明显差异。结论:Bold螺钉内固定有助于内踝骨折早期愈合和早期功能锻炼,是一种比较好的内固定材料,值得推广。     

Correction of collapsed nasal alae; a simple surgical procedure

Collapse of the nasal alae against the septum brings about a serious obstruction to the airway. Collapse may be overlooked on routine examination because the speculum may prevent it. In most cases alar collapse can be corrected by a simple surgical procedure, herein described, which can be readily done at the same time as operation on the caudal portion of the septum.     

Advances in the fracture mechanics of cortical bone

As cortical bone is a semi-brittle solid, its fracture is dependent not only on the magnitude of the applied stress, but also on the nature of any intrinsic or introduced cracks. Consequently a variety of fracture mechanics techniques have been utilised to evaluate the fracture toughness of cortical bone, including the single edge notched, centre notched cylindrical and compact tension methods, and values have been established for the critical stress intensity factor (Kc) and the critical strain energy release rate (Gc). The Kc and Gc values obtained depend on the orientation of the cortical bone, as well as on bone density, the velocity of crack propagation and specimen geometry. The significance of these fracture mechanics parameters for cortical bone is critically reviewed.