Assessment of inducible fracture micromotion in distal radial fractures using radiostereometry.

OBJECTIVES: This study examined the potential for measuring dynamic inducible micromotion (DIMM) between fragments in healing distal radial fractures using radiostereometry (RSA). DESIGN: Prospective imaging study. SETTING: University teaching hospital. PATIENTS: Nine patients with low-impact distal radial fractures. INTERVENTION: Volar locked plating of the fracture with insertion of tantalum beads into bone fragments. RSA examinations at 1 day and then 2, 6, 26, and 52 weeks. Motion at the fracture site was induced by maximal voluntary hand grip using a Jamar dynamometer. Radiographs were analyzed using locally developed and UMRSA software. MAIN OUTCOME MEASUREMENTS: DIMM and migration were calculated as translations and rotations of the main distal segment. Clinical precision was assessed under repeatability conditions. RESULTS: Precision (as 95% error limit) ranged from 0.06 to 0.13 mm and 0.5 to 0.8 degrees for migration, and from 0.10 to 0.14 mm and 0.6 to 1.0 degrees for DIMM. DIMM was characterized by axial and dorsal compression with dorsiflexion. The median DIMM of patients reached a maximum at 2 weeks: mainly as 0.3 mm axial compression, 0.3 mm dorsal compression, and 2.5 degrees dorsiflexion. DIMM ceased by 26 weeks, indicating union of all fractures. Fracture collapse continued until the 26-week measurement, ranging between 0.2 and 2.8 mm axially. Instability of some intraosseous markers was observed. CONCLUSIONS: The precision of this RSA method was sufficient to observe inducible movements occurring during fracture healing. This has the potential for quantifying rates of fracture union and improving understanding of the available treatments.

Self-reported benefits from successive bilateral cochlear implantation in post-lingually deafened adults: randomised controlled trial.

Adult users of unilateral Nucleus CI24 cochlear implants with the SPEAK processing strategy were randomised either to receive a second identical implant in the contralateral ear immediately, or to wait 12 months while they acted as controls for late-emerging benefits of the first implant. Twenty four subjects, twelve from each group, completed the study. Receipt of a second implant led to improvements in self-reported abilities in spatial hearing, quality of hearing, and hearing for speech, but to generally non-significant changes in measures of quality of life. Multivariate analyses showed that positive changes in quality of life were associated with improvements in hearing, but were offset by negative changes associated with worsening tinnitus. Even in a best-case scenario, in which no worsening of tinnitus was assumed to occur, the gain in quality of life was too small to achieve an acceptable cost-effectiveness ratio. The most promising strategies for improving the cost-effectiveness of bilateral implantation are to increase effectiveness through enhanced signal processing in binaural processors, and to reduce the cost of implant hardware.

Born again bone: tissue engineering for bone repair.

Destruction of bone tissue due to disease and inefficient bone healing after traumatic injury may be addressed by tissue engineering techniques. Growth factor, cytokine protein, and gene therapies will be developed, which, in conjunction with suitable carriers, will regenerate missing bone or help in cases of defective healing.

Direct measurement of cerebrospinal fluid pressure through the cochlea in a congenitally deaf child with Mondini dysplasia undergoing cochlear implantation.

OBJECTIVE: Perilymph/cerebrospinal fluid (CSF) "gushers" may occur at cochleostomy during cochlear implant surgery, particularly in patients with congenital cochlear duct malformation in which CSF in the internal auditory meatus is in direct communication with the perilymphatic space in the cochlea. The object of the study was to measure the pressure and flow of a CSF gusher at cochleostomy. STUDY DESIGN: The design was a preoperative pressure measurement. SETTING: The setting was a multidisciplinary cochlear implant program. PATIENT: A 4-year-old girl with bilateral Mondini deformity undergoing cochlear implantation was studied. INTERVENTION: A size 23 FG intravenous cannula was inserted into the cochlea and connected to a pediatric drip set to form an improvised manometer. MAIN OUTCOME MEASURE: Intracochlear fluid pressure was measured at 14 cm H2O, equivalent to the normal CSF pressure that would be recorded in a child of this age at lumbar puncture. An indirect measurement of the likely size of the CSF/perilymph defect was made. RESULTS: This technique may allow better assessment of the risk of postoperative CSF leakage and meningitis. CONCLUSION: This simple technique of measuring the pressure in a perilymph gusher can be used to assess the need for careful sealing of the cochleostomy, to measure the reduction in pressure produced by head elevation or a spinal drain, and to assess the probable size of a defect in the lamina cribrosa.

Open fractures of the tibia in children.

The results of the treatment of open tibial fractures in 58 children aged between 3 and 15 years are reviewed. There were 25 Gustilo Type I, 22 Type II and 10 Type III fractures. At operation 37 wounds were closed primarily and 21 wounds were left open. Of these 21, 13 healed by secondary intention and eight required split skin grafting or soft tissue flap coverage. Stable fractures were immobilized in an above-knee plaster in 48 cases (83 per cent) and six fractures treated with external fixation (10 per cent). Two patients (3.5 per cent) had cast immobilization of the tibial fracture and traction for an ipsilateral femoral fracture. Two patients (3.5 per cent) with Gustilo Type IIIc injuries required an amputation, one 'de novo' as the limb was not salvageable and one 4 days after failed vascular reconstruction. All fractures healed primarily without bone grafting, although there were three cases of delayed union and seven cases of malunion. Six children had superficial wound infections but there were no cases of deep infection or osteomyelitis. There was one case of compartment syndrome.

Interface pressures in below elbow casts.

Intra-cast pressures were measured in casts worn by patients with Colles' fractures and by volunteers. This study has shown that the loading as determined by the interface pressures in conventional backslab-below elbow casts is low and generally nonspecific. However, moulding the backslab increases the intra-cast pressures and these higher pressures are maintained throughout the period of immobilization as compared with non-moulded casts. There is no evidence of three-point loading in the casts; as a method of applying forces to the fracture site conventional casting does not appear to be particularly effective.

Extra-tympanic electrocochleography.

A non-invasive technique for recording the cochlear action potential in adults without recourse to sedation or local anaesthesia is presented. This technique has been assessed in two ways: (1) A group of normal subjects was tested to obtain distributions of response amplitude and latency as functions of stimulus intensity. (2) A group of patients with Meniere's disease was tested with trans- and extra-tympanic electrocochleography to compare the intensity amplitude functions and wave-forms obtained from the two methods. On the basis of this study the use of extra-tympanic electrocochleography as a replacement for the trans-tympanic method is discussed.

Effects of incubator noise on the cochlea of the newborn.

The possible effects of incubator noise on the hearing of premature babies have long been debated. The type of hearing loss found in 12 low-birthweight children was examined; and the variable noise level in regularly used incubators was measured. This noise, applied to guinea pigs continuously during their second week after birth, was shown histologically to destroy a proportion of the sensory cells in the cochlea. Adult guinea pigs, however, were not vulnerable in this way. The conclusion is that there is definite circumstantial evidence of the damaging effect of many incubators on the hearing of premature infants.

Deep vein thrombosis in ear, nose and throat surgery.

I. One hundred and three patients undergoing head and neck or ear operations were screened for deep vein thrombosis using I125 labelled fibrinogen. 2. No thrombosis was detected in thirty-five patients undergoing ear operations. 3. Nine (16%) of fifty-six patients who underwent head and neck operations subsequently developed deep vein thrombosis. In a further twelve patients undergoing head and neck operations the ankle was used as a drip site and seven of these patients developed thrombosis in that leg.