Paediatric tracheostomy tubes: recent developments and our current practice.

OBJECTIVE: A variety of paediatric tracheostomy tubes are available. This article reviews the tubes in current use at Great Ormond Street Hospital for Children and Evelina London Children's Hospital. METHODS: This paper outlines our current preferences, and the particular indications for different tracheostomy tubes, speaking valves and other attachments. RESULTS: Our preferred types of tubes have undergone significant design changes. This paper also reports further experience with certain tubes that may be useful in particular circumstances. An updated sizing chart is included for reference purposes. CONCLUSION: The choice of a paediatric tracheostomy tube remains largely determined by individual clinical requirements. Although we still favour a small range of tubes for use in the majority of our patients, there are circumstances in which other varieties are indicated.

A rare case of foreign body impaction requiring oesophagotomy.

We report a rare case of ingestion of a large stone in a male patient with a known psychiatric disorder. Failure of endoscopic removal necessitated retrieval of the impacted stone by an open oesophagotomy. This case highlights an important yet unusual presentation and management of an oesophageal foreign body.

Beware the silent presentation of a high and dehiscent jugular bulb in the external ear canal.

OBJECTIVE: We report two rare cases of high and dehiscent jugular bulbs protruding into the external ear canal; one case was silent, the other symptomatic. METHOD: The cases are presented and the relevant literature reviewed and discussed. RESULTS: A 52-year-old woman underwent mastoid exploration for suspected cholesteatoma. On raising the tympanomeatal flap, while still lateral to the annulus, brisk venous bleeding occurred from a high, dehiscent jugular bulb in the external ear canal. The second patient, a 42-year-old man, underwent imaging for suspected glomus tumour. A high, dehiscent jugular bulb was found protruding into the external ear canal and hypotympanum. CONCLUSION: High jugular bulbs in the middle ear have been reported many times. To our knowledge, there has only been one previous report of a high jugular bulb in the external ear. These cases illustrate the importance of full, accurate assessment of high resolution computed tomography images, and of appropriate, immediate management of bleeding.

What is the short term effect of perfumes on olfactory thresholds?

OBJECTIVES: Body sprays and perfumes are commonly worn by patients attending ENT out-patients clinics. Their effect on performance in olfactory testing is unknown. The aim of this study was to determine whether olfactory thresholds are altered by the presence of such fragrances. MATERIALS AND METHODS: One hundred and sixty healthy volunteers, aged 18 to 65 years, underwent olfactory thresholds testing. Each was then exposed to one of four strong perfumes, applied in a facemask for two minutes, and the thresholds were retested. RESULTS AND ANALYSIS: All olfactory thresholds worsened after being exposed to the strong perfumes of Lynx and Impulse body sprays, with the strongest effect being on olfactory detection of phenylethyl alcohol (p<0.001). CONCLUSIONS: Strong perfumes can have a negative effect on olfactory thresholds. SIGNIFICANCE: Patients attending olfactory threshold testing need to be advised not to wear body sprays or perfumes.

Histopathological changes in the human larynx following expanded polytetrafluroethylene (Gore-Tex(R)) implantation.

BACKGROUND: Expanded polytetrafluroethelyne (e PTFE, Gore-Tex(R)) has been advocated as an implant material for medialization of the vocal fold. Animal studies involving rabbits and a porcine model have demonstrated host tolerance of the implant. There have been no reports describing the histological changes in a human laryngectomy specimen with a Gore-Tex implant. CASE PRESENTATION: The histological findings in a laryngectomy specimen of a patient previously implanted with e PTFE for medialization of a paralyzed vocal fold following excision of a vagal neurofibroma were studied.Histopathology revealed a mild foreign-body giant cell granulomatous reaction with some associated fibrosis. The granulomatous response was limited to the periphery of the Gore-Tex and although it closely followed the profile of the material it did not encroach into or significantly break up the material. There was no significant neutrophilic or lymphocytic inflammation. CONCLUSIONS: Our findings are consistent with the animal models confirming that Gore-Tex implantation does not result in a significant granulomatous reaction in the human larynx over a 13-month period. Moreover, there is no evidence of resorption or infection. Further, the lack of lymphocytes in association with the granulomas indicates that there is no significant immunological hypersensitivity. Histologically, the slight permeation by connective tissue is similar to that seen in Gore-Tex vascular and cardiac implants. The degree of the slight giant cell response appears to be dependent on the profile of the material; a sharp edge incited more of a response than a flat surface.

Dementia: the cost of care for behaviourally disturbed patients living in the community.

OBJECTIVE: To determine the cost of care of people with dementia and behavioural disturbances living in the community, which is currently unknown. DESIGN, SETTING & PATIENTS: This is a study of 12 randomly selected subjects attending a continuing care dementia day facility for people with behavioural disturbances. MEASURES: Hours of care received from different sources were recorded and costed. RESULTS: The total mean direct costs to the public services was pound400 per person per week. Caregiver's time costed at professional rates were pound1208 per person per week. CONCLUSIONS: Unpaid caregivers supported by publicly funded agencies provide a less expensive service compared to specialised institutional care.

Alignment of total knee arthroplasty: the relationship to radiolucency around the tibial component.

Between January 1982 and July 1985, 122 cemented 'Accord' total knee replacements were performed. Out of this number, 21 were lost to follow-up because of death (in 16), revision (2) due to infection, and failure to attend (3). The post-operative alignment of 101 prostheses were compared to the incidence of radiolucencies around the tibial component at 5 years follow-up. The mechanical axis was used as a reference. The mean alignment was 0.99 degrees valgus with a standard deviation of 2.48 degrees. Some 72% of knees were within 3 degrees and 94% within 5 degrees of true alignment. Using two methods of assessing radiolucencies there was a non-significant relationship between the alignment and radiolucencies. The alignment tolerance with this prosthesis is, therefore, at least 5 degrees.

A tribological study of a series of retrieved accord knee explants.

A tribological study of a series of 27 retrieved Accord meniscal bearing knee joints has been carried out. The roughness of the articulating surfaces of the meniscal and the femoral components was investigated, and the penetration into the polyethylene meniscal component was determined. There was generally little damage to the highly polished metallic femoral components. A general polishing and smoothing of the ultra high molecular weight polyethylene meniscal components was observed, although there was some subsequent deterioration of the polyethylene surfaces in certain cases. The penetration rate of the femoral components into the menisci was low, and was found to be similar to that reported for other meniscal knee joints.

The collateral ligament flexion-extension test (CLEFT) in total knee replacement.

We present a simple preoperative clinical test, the collateral ligament extension-flexion test (CLEFT). In patients undergoing total knee arthroplasty, with a preoperative valgus or varus deformity, this test establishes which knees have balanced collateral ligaments. It predicts which knees will not require soft tissue adjustment during the course of their surgery despite, in some cases, large deformities. The mechanism of the test is based on the observation that, in certain patients, a deformity present in extension is seen to correct in flexion. The sensitivity of this observation was checked in 44 consecutive patients undergoing total knee arthroplasty, and who had either a valgus or varus deformity in extension greater than 10 degrees. In 34 patients the test was positive, and none of these required ipsilateral collateral ligament release. All of the 10 patients with a negative test required soft tissue adjustment. In patients undergoing unconstrained total knee arthroplasty this test is reliably predictive of those knees with preoperative deformity which can be corrected simply by correctly aligned bone cuts. It supports the principle of bony resection prior to soft tissue adjustment in this form of surgery.

Factors affecting the range of movement of total knee arthroplasty.

We have investigated those factors which influence the range of movement after total knee arthroplasty, including sex, age, preoperative diagnosis and preoperative flexion deformity and flexion range. We also compared cemented and cementless tibial fixation, the influence of collateral ligament and lateral parapatellar releases and of replacement of the patella, and of the period of postoperative immobilisation. We reviewed 516 Johnson-Elloy (Accord) knee arthroplasties performed between 1982 and 1989, with a minimum follow-up of 12 months. The most important factors in the range of flexion achieved after arthroplasty are the diagnosis and the preoperative range of flexion. In patients with osteoarthritis there was a mean loss of flexion; in rheumatoid arthritis there was a mean gain. In both groups, the stiffer knees gained motion and the more mobile knees lost it. Post-operative range of motion was not influenced significantly by cement fixation, collateral ligament or patellar retinacular releases, prolonged immobilisation or patellar replacement.

Five to eight year results of the Johnson-Elloy (Accord) total knee arthroplasty.

Between February 1982 and December 1985, 133 knees in 107 patients were replaced with a cemented Johnson-Elloy (Accord) total knee arthroplasty. Thirty-five knees were lost during the follow-up period because of death in 29, revision in 3, infection in 1, and refusal of follow-up evaluation in 2. The results of the remaining 98 knees in 76 patients with a 5-8 year follow-up period are presented. The procedure was carried out in all cases presenting for surgery, irrespective of pathology and degree of deformity. The range of flexion achieved as a mean of 93.5 degrees in the osteoarthritic group and 100 degrees in the rheumatoid arthritic group. Eighty-seven percent of the osteoarthritic group and 95% of the rheumatoid arthritic group achieved between 10 degrees and 50 degrees of rotation at 90 degrees of flexion, which was maintained for the duration of the study. Adequate stability in both groups, valgus-varus and rotation in extension, and anteroposterior in flexion was achieved. Survivorship was 97.7% at 80 months.

Accuracy of intramedullary alignment in total knee replacement.

The accuracy of a system of intramedullary alignment using 6 mm rods was assessed in 100 patients undergoing total knee replacements. Post-operative, full length weight-bearing X-rays were used; the mechanical axis from head was used as the reference axis. The method of calculating the errors produced by flexion and rotation of the limb in relation to the X-ray beam is described, the mean deviation from the mechanical axis in 100 cases being 0.67 degrees valgus with a standard deviation of 2.47 degrees. The maximum error was 6.68 degrees valgus and 4.62 degrees varus. The purpose of this study is twofold, first to assess the accuracy of this system of intramedullary alignment and, second, to develop a method of correcting for apparent radiological misalignment using standard radiographic equipment.

Holding power impaired in rheumatoid femoral heads. Cadaveric study of fracture fixation devices.

A measurement was made of the holding strength and the energy needed to extract a NoLok hip screw, a von Bahr screw, and a Hansson hookpin from cadaveric femoral heads. The specimens were obtained from female subjects aged 65 years or more, with 36 specimens each from rheumatoid (RA) and nonrheumatoid (non-RA) donors. Retraction of the implants was made by a continuous uniaxial pullout at 10 mm/min. For each type of device, the holding strength in rheumatoid femoral heads was less than in non-RA specimens. In rheumatoid specimens the maximum holding strength for the NoLok screw (1,622 N) was higher than that of the other two devices, whereas the von Bahr screw (1,177 N) had a higher maximum holding strength than the Hansson hook-pin (603 N). In non-RA, there was no difference in maximum holding power between the NoLok screw (2,549 N) and the von Bahr screw (2,282 N); however, both had a higher holding strength than the Hansson hook-pin (851 N). A rapid fall off was experienced in the force required to continue extraction of both types of screws, whereas for the Hansson hook-pin the strength decreased slowly. For each type of device, the energy needed for extraction of the implant was less in the RA group femoral heads, while there were no differences in total extraction energy between devices.

A new system to produce intraoperatively custom femoral prosthesis from measurements taken during the surgical procedure.

A system has been developed that allows the surgeon to match a prosthesis to any femoral cavity. The surgeon may choose how and where it will preferentially fit. The surgeon does not have to create a cavity to suit a premade prosthesis. The system is based on a novel technique for making a mold of the prepared femoral cavity. This is accurately and thoroughly measured using a laser. An implant is designed and manufactured while the operation is in progress using state-of-the-art computer and machining techniques. All important parameters such as neck length, offset, and anteversion are fully variable intraoperatively. To date, more than 800 consecutive procedures have been carried out. In a limited trial, no subjective difference was found with a cemented Charnley total hip arthroplasty at one year. It currently takes about 40 minutes to manufacture the implant and make it available in the operating room, and this time is being continually reduced. Using a femur first approach, operating time is not greatly extended. In the future, perhaps the operating time will not be extended at all. All data including cavity geometry are centrally recorded for analysis.

Fixation of unstable trochanteric hip fractures. A cadaver study comparing three different devices.

A four-fragment trochanteric fracture was produced in 24 human cadaver femora. After reduction to anatomic position, the fractures were stabilized by either a Jewett 135 degree nail-plate, a 135 degree Nolok sliding screw-plate without a key, or a 140 degree Hansson pin-plate with an additional trochanteric plate. Using a hip-force simulator, the preparations were subjected to 10,000 loading cycles simulating partial weight bearing, followed by another 10,000 cycles with full weight bearing, while measuring the elastic and permanent fracture displacements. Failure occurred in 3/8 of the Jewett stabilized fractures and in 1/8 each of the Nolok and Hansson stabilized specimens. Each failure was preceded by an increase in elastic tilt and rotation followed by a permanent rotation after which failure occurred as varus angulation of the fracture. Further, two Jewett nails, one Nolok screw, and three Hansson pins showed bending. Due to the controlled telescopic action in the Nolok and Hansson dynamic devices, the resistance to fatigue when subjected to repetitive loadings was increased and thereby a better overall result was achieved when compared with the rigid Jewett nail-plate. To maintain the dynamic function, the strength of the dynamic screw-pin must be sufficient to withstand physiologic loadings without bending; otherwise, the telescopic action will be obstructed.

Stability of osteosynthesis in trochanteric fractures. Comparison of three fixation devices in cadavers.

Stable trochanteric fractures were produced in 12 pairs of human cadaver femora, which were fixed by either a 135 degree Jewett nail plate, a 135 degree NoLok sliding screw/plate, or a 140 degree Hansson pin/plate. The bone-implant preparations were then subjected to 20,000 load cycles simulating full weight bearing, measuring the elastic and permanent fracture displacement. In each case, elastic displacement occurred during loading. For the Jewett-stabilized fractures, a steady increased elastic displacement, as well as permanent displacement, was seen throughout the test, causing 2/8 failures when the implant penetrated the femoral head. In the NoLok- and Hansson-stabilized fractures, there were no failures, both giving better overall stability than the Jewett device with sufficient fracture stability throughout the test.

Fixation of trochanteric hip fractures. A cadaver study of static and dynamic loading.

Human cadaveric femora were subjected to static and uniaxial dynamic load applied on the femoral head by a simulator. By two transducer-mounted aluminium rings attached to the bone, the static and the dynamic load causing an elastic deformation of 1 mm in the trochanteric region was assessed. A trochanteric fracture was then produced and stabilized by one of three fixation devices, after which the test was repeated. The unfractured femora had the most rigid appearance (static load, 25.9 KN/mm; dynamic load, 33.1 KN/mm). Of the fractured and stabilized specimens, the Jewett nail-plate gave the most rigid fixation (static load, 5.4 KN/mm; dynamic load, 11.5 KN/mm). The least rigid femora were those stabilized by the dynamic Nolok (static, 4.7 KN/mm; dynamic, 9.2 KN/mm) and Hansson (static, 3.2 KN/mm; dynamic 6.1 KN/mm) telescoping devices. Because of the viscoelastic properties of bone, the load applied in a hip simulator should be dynamic; otherwise, the ability of the device to withstand in vivo loading might be underestimated.