A review of high frequency oscillation ventilation in the neonate

In this study the use of high frequency oscillation (HFO) to treat neonates with respiratory failure is analysed. The theories behind gas exchange during HFO are reviewed and its specific application to neonatal care discussed. The mechanical performance of three HFO ventilators currently in use is compared with the views of medical staff operating them on a regular basis. The complex interactions between initial ventilator settings have led to difficulties in accurately comparing performance characteristics and ventilation strategies; each ventilator is seen to have its own strengths and weaknesses that contribute to the ventilator selection made. These interactions together with the specific HFO modes available on each ventilator should be taken into account when using a HFO for the first time or when switching from an alternative ventilation method. Medical staff who care for neonates suggest staff education and training into the variations of HFO will greatly improve its use in neonatal medicine.

Lubrication regime of the contact between fat and bone in bovine tissue

Fat pads are masses of encapsulated adipose tissue located throughout the human body. Whilst a number of studies describe these soft tissues anatomically little is known about their biomechanics, and surgeons may excise them arthroscopically if they hinder visual inspection of the joint or bursa. By measuring the coefficient of friction between, and performing Sommerfeld analysis of, the surfaces approximating the in vivo conjuncture, this contact has been shown to have a coefficient of friction of the order of 0.01. The system appears to be lubricated hydrodynamically, thus possibly promoting low levels of wear. It is suggested that one of the functions of fat pads associated with subtendinous bursae and synovial joints is to generate a hydrodynamic lubricating layer between the opposing surfaces.

Applications of nanotechnology in orthopaedics

Nanotechnology is the application of science and engineering at the nanoscale. A diverse range of applications are beginning to emerge in all areas of medicine. We performed a survey from November 2005 to March 2006 using the Internet search engines PubMed, ScienceDirect, ISI Web of Knowledge, and Google Scholar. We report on the role of nanotechnology in orthopaedics, exploring current and potential applications. Nanostructured materials have been proposed as the next generation of orthopaedic implant properties by creating a surface environment more conducive for osteoblast function. Bone substitute materials, whose nanoscale composition emulates the hierarchic organization of natural bone, shows initiation of the desirable formation of an apatite layer. Nanotechnology also has been harnessed to improve the cutting performance and quality of surgical blades. Postoperative infection rates may be reduced by using nanofibrous membrane wound dressings containing antibacterial properties. The most notable application of nanotechnology in orthopaedics may be drug delivery, including nanotherapeutics for treating bone cancer and arthritis. Nanotechnology is being used in orthopaedics, and likely will play a valuable role in future developments.

Literature review of current techniques for the insertion of distal screws into intramedullary locking nails

The procedure for distal interlocking of intramedullary nails can be difficult and time consuming. Following nail insertion, the problems associated with the location of the distal holes and correct screw placements are well known. Numerous techniques and devices have been proposed to aid distal targeting, in attempts to overcome some of the associated problems. The development of the techniques and devices continues. A review of the literature is therefore timely, in order to provide awareness of the current situation. An overview is presented of the various distal targeting methods reported in the literature.

A model of dynamic sacro–iliac joint instability from malrecruitment of gluteus maximus and biceps femoris muscles resulting in low back pain

The objective of this work is to propose a biomechanical model of sacro-iliac joint dysfunction as a cause of low back pain. Sacro-iliac joint is known to be a source of low back pain. We also know that it is a very stable joint with little mobility. Surrounding lower limb and back muscles contribute a major part of this stability. Gait analysis studies have revealed an orderly sequence of muscle activation when we walk - that contributes to efficient stabilisation of the joint and effective weight transfer to the lower limb. Gluteus maximus fibres-lying almost perpendicular to the joint surfaces are ideally oriented for this purpose. Biceps femoris is another important muscle that can also influence joint stability by its proximal attachment to sacrotuberous ligament. Altered pattern of muscle recruitment has been observed in patients with low back pain. But we do not know the exact cause-effect relationship. Because of its position as a key linkage in transmission of weight from the upper limbs to the lower, poor joint stability could have major consequences on weight bearing. It is proposed that sacro-iliac joint dysfunction can result from malrecruitment of gluteus maximus motor units during weight bearing. This results in compensatory biceps over activation. The resulting soft tissue strain and joint instability may manifest itself in low back pain. If our hypothesis holds true, it may have positive implications for patients with sacro-iliac joint dysfunction - who could be offered a definite diagnosis and targeted physiotherapy. It may be possible to identify patients early in a primary care setting and offer direct physio referral. They could benefit from exercises to improve strengthening and recruitment of the affected muscles.

Subdural haemorrhage sustained in a baby-rocker? A biomechanical approach to causation

An unconscious 8 weeks old infant was admitted to hospital and found to have bilateral, subdural and retinal haemorrhages. He died the following day. The explanation for the subdural haemorrhage put forward by his carers was that the infant had been in a baby-rocker and that the carers had seen the rocker being rocked vigorously by their 14 months old daughter on two separate occasions. This paper describes the biomechanics of an infant model in the particular baby-rocker used and determines the maximum forces generated, comparing them with the 'forces' thought to be compatible with the causation of subdural haemorrhage.