Spring-mass behavioural adaptations to acute changes in prosthetic blade stiffness during submaximal running in unilateral transtibial prosthesis users

BACKGROUND

Individuals with lower-limb amputation can use running specific prostheses (RSP) that store and then return elastic energy during stance. However, it is unclear whether varying the stiffness category of the same RSP affects spring-mass behaviour during self-selected, submaximal speed running in individuals with unilateral transtibial amputation.

RESEARCH QUESTION

The current study investigates how varying RSP stiffness affects limb stiffness, running performance, and associated joint kinetics in individuals with a unilateral transtibial amputation.

METHODS

Kinematic and ground reaction force data were collected from eight males with unilateral transtibial amputation who ran at self-selected submaximal speeds along a 15 m runway in three RSP stiffness conditions; recommended habitual stiffness (HAB) and, following 10-minutes of familiarisation, stiffness categories above (+1) and below (-1) the HAB. Stance-phase centre of mass velocity, contact time, limb stiffness' and joint/RSP work were computed for each limb across RSP stiffness conditions.

RESULTS

With increased RSP stiffness, prosthetic limb stiffness increased, whilst intact limb stiffness decreased slightly (p<0.03). Centre of mass forward velocity during stance-phase (p<0.02) and contact time (p<0.04) were higher in the intact limb and lower in the prosthetic limb but were unaffected by RSP stiffness. Intact limb hip joint positive work increased for both the +1 and -1 conditions but remained unchanged across conditions in the prosthetic limb (p<0.02).

SIGNIFICANCE

In response to changes in RSP stiffness, there were acute increased mechanical demands on the intact limb, reflecting a reliance on the intact limb during running. However, overall running speed was unaffected, suggesting participants acutely adapted to an RSP of a non-prescribed stiffness.

Pelvic organ motion and dosimetric implications during horizontal patient rotation for prostate radiation therapy

PURPOSE

Gantry-free radiation therapy systems utilizing patient rotation would be simpler and more cost effective than the conventional gantry-based systems. Such a system could enable the expansion of radiation therapy to meet global demand and reduce capital costs. Recent advances in adaptive radiation therapy could potentially be applied to correct for gravitational deformation during horizontal patient rotation. This study aims to quantify the pelvic organ motion and the dosimetric implications of horizontal rotation for prostate intensity-modulated radiation therapy (IMRT) treatments.

METHODS

Eight human participants who previously received prostate radiation therapy were imaged in a clinical magnetic resonance imaging (MRI) scanner using a bespoke patient rotation system (PRS). The patients were imaged every 45 degrees during a full roll rotation (0-360 degrees). Whole pelvic bone, prostate, rectum, and bladder motion were compared to the supine position using dice similarity coefficient (DSC) and mean absolute surface distance (MASD). Prostate centroid motion was compared in the left-right (LR), superior-inferior (SI), and anterior-posterior (AP) direction prior to and following pelvic bone-guided rigid registration. Seven-field prostate IMRT treatment plans were generated for each patient rotation angles under three adaption scenarios: No plan adaption, rigid planning target volume (PTV)-guided alignment to the prostate, and plan re-optimization. Prostate, rectum, and bladder doses were compared for each adaption scenario.

RESULTS

Pelvic bone motion within the PRS of up to 53 mm relative to the supine position was observed for some participants. Internal organ motion was greatest at the 180-degree PRS couch angle (prone), with prostate centroid motion range < 2 mm LR, 0 mm to 14 mm SI, and -11 mm to 4 mm AP. Rotation with no adaption of the treatment plan resulted in an underdose to the PTV -- in some instances up to 75% (D95%: 78 ± 0.3 Gy at supine to 20 ± 15.0 Gy at the 225-degree PRS couch angle). Bladder dose was reduced during the rotation by up to 98% (V60 Gy: 15.0 ± 9.4% supine to 0.3 ± 0.5% at the 225-degree PRS couch angle). In some instances, the rectum dose increased during rotation (V60Gy: 20.0 ± 4.5% supine to 25.0 ± 15.0% at the 135-degree PRS couch angle). Rigid PTV-guided alignment resulted in PTV coverage which, though statistically lower (P < 0.05 for all D95% values), was within 1 Gy of the supine plans. Plan re-optimization resulted in a statistically equivalent PTV coverage compared to the supine plans (P > 0.05 for all D95% metrics and all within ±0.4 Gy). For both rigid PTV-guided alignment and plan re-optimization, rectum dose volume metrics were reduced compared to the supine position between the 90- and 225-degree PRS couch angles (P < 0.05). Bladder dose volume metrics were not impacted by rotation.

CONCLUSION

Pelvic bone and internal organ motion are present during patient rotation. Rigid PTV-guided alignment to the prostate will be a requirement if prostate IMRT is to be safely delivered using patient rotation. Plan re-optimization for each PRS couch angle to account for anatomical deformations further improves the PTV coverage.

Chronic low back pain in traumatic lower limb amputees

Objective: To ascertain the prevalence of back pain amongst traumatic lower limb amputees attending a regional rehabilitation centre and to determine the possible causes of back pain.

Design: All traumatic lower limb amputees given a semi-structured questionnaire to complete and a comparative subgroup of amputees with back pain and without back pain underwent physical examination, gait analysis, magnetic resonance scanning (MRI) and gait/standing stability analysis.

Setting: A subregional amputee rehabilitation centre.

Results: Transfemoral amputees were more likely to suffer from back pain (81%) than transtibial amputees (62%) (p≤0.05) and of those suffering from severe back pain, 89% and 81% also suffered from severe pain in the phantom limb and severe stump pain respectively. In two comparative subgroups of amputees there was no significant difference between back pain and pain-free groups except those with pain were more likely to have a body mass index (BMI) ratio above 50% of the recommended ratio. No difference in degeneration or disc disease between the groups on MR scans was found. Impact ground reaction forces during walking, irrespective of limb, were significantly greater (p≤0.05) in the pain-free group than in the pain group, as was walking speed. Gait asymmetry measures were similar in both groups. Centre of pressure displacement measures during standing were greater in the pain group than in the pain-free group.

Conclusions: Low back pain in amputees is a significant problem equal to that of pain in the phantom limb and a biomechanical (myofascial) rather than a degenerative aetiology is suggested.

The mechanics of landing when stepping down in unilateral lower-limb amputees

BACKGROUND

The ability to successfully negotiate stairs and steps is an important factor for functional independence. While work has been undertaken to understand the biomechanics of gait in lower-limb amputees, little is known about how amputees negotiate stairs and steps. This study aimed to determine the mechanics of landing in unilateral lower-limb amputees when stepping down to a new level. A secondary aim was to assess the effects of using a shank-mounted shock-absorbing device (Tele-Torsion Pylon) on the mechanics of landing.

METHODS

Ten unilateral amputees (five transfemoral and five transtibial) and eight able-bodied controls performed single steps down to a new level (73 and 219 mm). Trials were repeated in amputees with the Tele-Torsion Pylon active and inactive. The mechanics of landing were evaluated by analysing peak limb longitudinal force, maximal limb shortening, lower extremity stiffness, and knee joint angular displacement during the initial contact period, and limb and ankle angle at the instant of ground-contact. Data were collected using a Vicon 3D motion analysis system and two force platforms.

FINDINGS

Amputees landed on a straightened and near vertical limb. This limb position was maintained in transfemoral amputees, whereas in transtibial amputees knee flexion occurred. As a result lower extremity stiffness was significantly greater in transfemoral amputees compared to transtibial amputees and able-bodied controls (P<0.001). The Tele-Torsion Pylon had little effect on the mechanics of landing in transtibial amputees, but brought about a reduction in lower extremity stiffness in transfemoral amputees (P<0.05).

INTERPRETATION

Amputees used a stepping strategy that ensured the direction of the ground reaction force vector was kept anterior of the knee joint centre. Using a Tele-Torsion Pylon may improve the mechanics of landing during downward stepping in transfemoral amputees.

The gait initiation process in unilateral lower-limb amputees when stepping up and stepping down to a new level

BACKGROUND

Unilateral lower-limb amputees lead with their intact limb when stepping up and with their prosthesis when stepping down; the gait initiation process for the different stepping directions has not previously been investigated.

METHODS

Ten unilateral amputees (5 transfemoral and 5 transtibial) and 8 able-bodied controls performed single steps up and single steps down to a new level (73 and 219 mm). Duration, a-p and m-l centre of mass and centre of pressure peak displacements and centre of mass peak velocity of the anticipatory postural adjustment and step execution phase were evaluated for each stepping direction by analysing data collected using a Vicon 3D motion analysis system.

FINDINGS

There were significant differences (in the phase duration, peak a-p and m-l centre of pressure displacement and peak a-p and m-l centre of mass velocity at heel-off and at foot-contact) between both amputee sub-groups and controls (P<0.05), but not between amputee sub-groups. These group differences were mainly a result of amputees adopting a different gait initiation strategy for each stepping direction.

INTERPRETATION

Findings indicate the gait initiation process utilised by lower-limb amputees was dependent on the direction of stepping and more particularly by which limb the amputee led with; this suggests that the balance and postural control of gait initiation is not governed by a fixed motor program, and thus that becoming an amputee will require time and training to develop alternative neuromuscular control and coordination strategies. These findings should be considered when developing training/rehabilitation programs.

Surgical treatment of cervical node metastases from squamous carcinoma of the upper aerodigestive tract: evaluation of the evidence for modifications of neck dissection

BACKGROUND

This review article examines the role of the different types of neck dissection in the treatment of squamous carcinoma metastases to the cervical nodes.

METHODS

A critical evaluation of the literature on the pathologic basis, oncologic effectiveness, and functional outcome of neck dissection.

RESULTS

Pathologic data show preferential metastasis to different lymph node levels, in N0- and N+-staged disease, depending on the primary tumor site. Comparative studies on control of regional metastases suggest that modified radical is no less effective than radical neck dissection, but there is insufficient data to draw firm conclusions on the role of selective neck dissection. Selective and modified radical dissections result in less shoulder disability than radical neck dissection.

CONCLUSIONS

Modified radical neck dissection is supported by pathologic and clinical evidence in N1- and 2-staged disease. There may be a role for selective dissection, but there is a need for more information on oncologic outcome. Prospective multicenter systematic data collection on the outcome of neck dissection is a pragmatic alternative to a trial.

The treatment of distant metastases in head and neck cancer--present and future

At the present time the occurrence of distant metastases in patients with head and neck squamous cell carcinoma means that lifespan is measured in months. In most instances treatment is purely palliative. Isolated lung metastasis can be successfully removed with long-term disease control in selected patients. Radiotherapy can be useful for palliation of bone metastases and occasionally lung or brain metastases. Chemotherapy does not have a major impact at the present time except for the treatment of metastases from nasopharyngeal cancer. Palliative symptomatic care, along with appropriate pain control, is essential since pain management is very important in these patients. A significant change in the survival of patients with head and neck cancer is only likely to occur by the development of new approaches to treatment. Blocking tumor angiogenesis and treatment based on genetic abnormalities or cell surface receptors offer the two strategies that are most likely to be successful.

General considerations on distant metastases from head and neck cancer

Mortality in head and neck cancer is due to locoregional disease, distant metastases or intercurrent disease. As treatment of the primary tumor and cervical metastases has improved, the proportion of deaths from co-morbidity and from distant metastases has increased. Distant metastases almost invariably herald a poor prognosis in head and neck cancer with an average survival of 4.3-7.3 months and treatment is usually palliative. Reliable detection is important to prevent inappropriate treatment. The risk is related to the site, stage and histology of the primary tumor and the presence of cervical metastases. Early detection and treatment of cervical metastases may prevent distant metastases. Accurate staging of tumors helps to identify high-risk tumors that should be specifically investigated for distant metastases.

Screening tests to evaluate distant metastases in head and neck cancer

Investigation for distant metastases is part of the staging process of a primary tumor or recurrent disease before treatment. The lung is the most frequent site followed by bone and liver. Advanced stage and cervical metastases are the most important predictors of metastases. Almost all distant metastases are associated with lung metastases. Computed tomography scan of the chest is the single most effective investigation. The value of routine screening tests is questionable and merits further investigation.

Muscle power patterns in the mid-acceleration phase of sprinting

To assess the role of the lower limb joints in generating velocity in the mid-acceleration phase of sprinting, muscle power patterns of the hip, knee and ankle were determined. Six male sprinters with a mean 100 m time of 10.75 s performed repeated maximal sprints along a 35 m indoor track. A complete stride across a force platform, positioned at approximately 14 m into the sprint, was video-recorded for analysis. Smoothed coordinate data were obtained from manual digitization of (50 Hz) video images and were then interpolated to match the sampling rate of the recorded ground reaction force (1000 Hz). The moment at each joint was then calculated using inverse dynamics and multiplied by the angular velocity to determine the muscle power. The results showed a proximal-to-distal timing in the generation of peak extensor power during stance at the hip, the knee and then the ankle, with the plantar flexors producing the greatest peak power. Apart from a moderate power generation peak towards toe-off, knee power was negligible despite a large extensor moment throughout stance. The role of the knee thus appears to be one of maintaining the centre of mass height and enabling the power generated at the hip to be transferred to the ankle.

Cervical node metastases in laryngeal and hypopharyngeal cancer: a prospective analysis of prevalence and distribution

BACKGROUND

We have prospectively analyzed the prevalence and distribution of histologic cervical node metastases in laryngeal and hypopharyngeal squamous carcinoma to determine the most appropriate form of neck dissection.

METHODS

We have examined specimens from 100 consecutive patients in whom neck dissection was part of the primary treatment of laryngeal and hypopharyngeal carcinoma. Fifty eight patients were treated by unilateral or bilateral selective dissection of levels I to IV +/- VI for N0 disease and 42 by comprehensive dissection for N+ disease. Assessment was by separation of the specimens into node levels at the time of surgery and embedding all the resected material for histologic analysis.

RESULTS

Nodal metastases were found in 36% of ipsilateral and 27% of contralateral dissections in the N0 cases. The corresponding prevalences in N+ cases were 90% and 37%, respectively. All metastases in N0 and N1 disease were confined to levels II, III, IV, and VI. Metastases to levels I and V were infrequent even in N+ disease.

CONCLUSIONS

Our results support the use of elective dissection of node levels II to IV for N0 laryngeal and hypopharyngeal carcinoma. We suggest the inclusion of level VI nodes for tumors invading the subglottis, pyriform fossa apex, and postcricoid region. The prevalence of bilateral metastases is great enough in midline or bilateral tumors to justify bilateral selective dissection. It is possible that selective neck dissection is also adequate for small palpable metastases, but greater numbers are required to confirm this.

Biomechanical adaptations of transtibial amputee sprinting in athletes using dedicated prostheses

OBJECTIVE

To determine the biomechanical adaptations of the prosthetic and sound limbs in two of the world's best transtibial amputee athletes whilst sprinting.

DESIGN

Case study design, repeated measures.

BACKGROUND

Using dedicated sprint prostheses transtibial amputees have run the 100 m in a little over 11 s. Lower-limb biomechanics when using such prostheses have not previously been investigated.

METHODS

Moments, muscle powers and the mechanical work done at the joints of the prosthetic and sound limbs were calculated as subjects performed repeated maximal sprint trials using a Sprint Flex or Cheetah prosthesis.

RESULTS

An increased hip extension moment on the prosthetic limb, with an accompanying increase in the amount of concentric work done, was the most notable adaptation in Subject 1 using either prosthesis. In Subject 2, an increased extension moment at the residual knee, and an accompanying increase in the amount of total work done, was the most notable adaptation using either prosthesis. This later adaptation was also evident in Subject 1 when using his Sprint Flex prosthesis.

CONCLUSIONS

Increased hip work on the prosthetic limb has previously been shown to be the major compensatory mechanism that allow transtibial amputees to run. The increased work found at the residual knee, suggests that the two amputee sprinters used an additional compensatory mechanism.

RELEVANCE

These findings provide an insight into the biomechanical adaptations that allow a transtibial amputee to attain the speeds achieved when sprinting.

Cancer spread in the larynx: a pathologic basis for conservation surgery

BACKGROUND

Previous pathologic studies of the spread of laryngeal carcinoma have drawn inferences about the site of origin of tumors, their mechanisms of growth, or the role of structures as potential barriers to tumor spread. Most of the information is based on the study of advanced or recurrent tumors and is difficult to apply to conservation surgical technique. We carried out a systematic analysis of a wide range of laryngeal tumors with the aim of providing a basis for conservation surgery.

METHODS

We analyzed tumor invasion of the laryngeal spaces and the laryngeal framework in relation to the mucosal tumor extent by axial sectioning of 80 sequential partial and total laryngectomy specimens.

RESULTS

Invasion of a particular laryngeal space could be accurately predicted by mucosal tumor extent and vocal cord mobility. Invasion of the laryngeal framework was associated with tumor extension to the ventricle, subglottis, or pyriform fossa. The thyroid cartilage and the cricothyroid space and ligament were the most frequent sites of invasion.

CONCLUSIONS

The mucosal distribution of a tumor and observation of vocal cord mobility can be used to determine accurately the extent of tumor invasion of the laryngeal spaces and framework and therefore the extent of resection necessary.

Sprint kinematics of athletes with lower-limb amputations

OBJECTIVE

To determine and compare the kinematics of the sound and prosthetic limb in five of the world's best unilateral amputee sprinters.

SUBJECTS

Five men, all unilateral lower-limb amputee (one transfemoral, four transtibial) athletes. The individual with transfemoral amputation used a Endolite Hi-activity prosthesis incorporating a CaTech hydraulic swing and stance control unit, a Flex-Foot Modular III, and an ischial containment total contact socket. Those with transtibial amputations used prostheses incorporating a Flex-Foot Modular III and patellar tendon-bearing socket, with silicone sheath liner (Iceross) and lanyard suspension.

DESIGN

Case series. Subjects were videotaped sprinting through a performance area. Sagittal plane lower-limb kinematics derived from manual digitization (at 50 Hz) of the video were determined for three sprint trials of the prosthetic and sound limb. Hip, knee, and ankle kinematics of each subject's sound and prosthetic limb were compared to highlight kinematic alterations resulting from the use of individual prostheses. Comparisons were also made with mean data from five able-bodied men who had similar sprinting ability.

RESULTS

Sound limb hip and knee kinematics in all subjects with amputation were comparable to those in able-bodied subjects. The prosthetic knee of the transfemoral amputee athlete fully extended early in swing and remained so through stance. In the transtibial amputee athletes, as in able-bodied subjects, a pattern of stance flexion-extension was evident for both limbs. During stance, prosthetic ankle angles of the transtibial amputee subjects were similar to those of the sound side and those of able-bodied subjects.

CONCLUSION

Prosthetic limb kinematics in transtibial amputee subjects were similar to those for the sound limb, and individuals achieved an "up-on-the-toes" gait typical of able-bodied sprinting. Kinematics for the prosthetic limb of the transfemoral amputee subject were more typical of those seen for walking. This resulted in a sprinting gait with large kinematic asymmetries between contralateral limbs.

Fine needle cytology of palpable head and neck lesions: a comparison of sampling methods with and without suction

Patients attending the ear, nose and throat (ENT) department at St James's University Hospital, Leeds, UK, for evaluation of palpable head and neck lesions have a fine needle cytology (FNC) specimen taken and receive the result at the same out-patient visit. This study was designed to discover if there is a significant difference in the efficiency of the methods with and without suction. The method was chosen randomly on each occasion and the adequacy or otherwise of the specimen was determined taking into account the site and nature of the lesion and the total cellularity of the sample. The level of blood contamination was also compared by each method. When benign and malignant lesions from all sites were analysed together the method with suction produced a significantly higher number of adequate samples than the method without suction. The exception was in the case of samples from lymph node lesions measuring < 1 cm, where adequate specimens were only obtained without suction. The non-suction technique was particularly poor at sampling salivary gland lesions in the 1-1.5 cm category. There was no significant difference in the level of blood contamination between the two methods at any site. These results are at variance with most other similar studies and possible reasons for this are discussed.

An evaluation of the changes in maxillary pulpal blood flow associated with orthognathic surgery

The objective of this study was to evaluate the use of the Laser Döppler Flowmeter (LDF) in the measurement of pulpal blood flow following orthognathic surgery and to conduct an initial study of the effects of a Le Fort I osteotomy on the pulpal blood flow of the maxillary central incisors. The design consisted of a preliminary prospective controlled consecutive clinical trial undertaken at the Orthodontic Clinic, University Dental Hospital NHS Trust, Wales, 1994. The study group consisted of 15 consecutive patients who were to receive a standard advancement Le Fort I osteotomy. Seven patients who were to undergo a mandibular advancement only acted as a control. A further 20 separate patients participated in a study for the assessment of measurement error. The blood flow in relative perfusion unit v. time, was measured using a Laser Döppler Flowmeter. Measurement error for flowmeter recordings with hand-held application and custom-made splint support showed no consistent difference or significant random variation between the two methods for holding the probe against the teeth (pooled S.D. of reproducibility 1/1 = 1.91/1.39 for custom splint location as opposed to 0.96/1.07 for hand-held/fixed bracket location). For the surgical patients under investigation no significant differences for maxillary pulpal blood flow were found in the control group (mandibular osteotomy) over time. However, in the maxillary osteotomy patients there was a tendency for an initial rise in the maxillary perfusion post-surgery as measured at the central incisor pulps, followed by an overall reduction at 6 months. As an example, the mean value for the upper right central showed a significant increase in blood flow during the immediate post-operative period (P < 0.05), but at 6 months after surgery demonstrated a statistically significant overall reduction in comparison with the presurgical reading (P < 0.001). The laser Döppler flowmeter is not an easy instrument to use in the clinical assessment of pulpal blood flow. However, it would appear from these longitudinal series of readings, taken over a 6-month period on 15 patients, that the maxillary perfusion recorded at the central incisor pulps may be permanently affected in many Le Fort I osteotomy patients. For patients that already have a prejudiced blood supply this could lead to devitalization and discoloration of incisors. It is not known if this affect on the perfusion of the pulp continues beyond 6 months post-surgery.

Temporalis fascia grafts shrink

Temporalis fascia, placed as an underlay graft, is commonly used to repair tympanic membrane perforations. Graft failure, however, is a well recognized complication. Grafts are often allowed to dry out during the procedure and, therefore, are often positioned in a dry or partially dehydrated state and only become fully rehydrated after placement. This study looked at how the size of the temporalis fascia alters with its state of hydration. The size of 20 temporalis fascia grafts was measured when fresh, after flattening and allowing them to dry, and finally after rehydrating the grafts with 0.9 per cent saline solution. Significant shrinkage was demonstrated. It is therefore proposed that a cause of increased failure rates, particularly in anterior myringoplasties, is loss of underlay due to graft rehydration and shrinkage. Thus graft shrinkage should be considered when positioning the graft.

Energy cost of walking: comparison of "intelligent prosthesis" with conventional mechanism

OBJECTIVE

To determine physiological energy cost with Blatchford's "Intelligent Prosthesis" (IP) compared to energy cost with a conventional pneumatic swing phase control (PSPC) mechanism.

DESIGN

Before-After trial: subjects fitted with IP walked on programmable treadmill at speeds: 6 min slow, 6 min fast, 8 min while speed changed, between slow, normal, and fast, every minute, and 6 min normal. Breath-by-breath analysis of subject's expired air determined average Vo2 (L/min) within each period. Procedure repeated after 1-week interval using PSPC prosthesis. Testing sessions supervised by experienced prosthetist.

SETTING

Rehabilitation centre.

SUBJECTS

Volunteer sample. Three men, unilateral transfemoral traumatic amputee patients, ages 39 to 59 years. Normally used ischial containment socket, Blatchford Endolite Stabilised Stance Flex knee with PSPC and Multiflex foot and ankle.

INTERVENTIONS

Fitting, programming, and alignment of IP (own socket) by Bioengineering Unit's resident prosthetist, IP's microprocessor programmed to facilitate five walking speeds.

MAIN OUTCOME MEASURE

Physiological energy cost (Vo2), of using IP compared to using PSPC mechanism.

RESULTS

Two subjects displayed reduced Vo2 of between 5.6% and 9.0% using IP compared to PSPC prosthesis at a pace either faster or slower than their normal pace. Third subject showed no significant change in oxygen consumption despite IP unit being heavier. All subjects displayed reduced Vo2 (averaging 4.1%) using IP for period of variable speed walking.

CONCLUSIONS

Although differences were small, they tend to indicate that use of the heavier IP unit lowered the energy cost of walking at speeds other than the amputee's normal pace.

The location and tracking of swallowed dental appliances: the role of radiology

Two cases of swallowing mishaps, one involving a spoon-denture and the other an orthodontic partial arch wire, are reported. The former was recovered following interventional radiology, the latter by proctoscopy. The role of radiographic investigation and possible measures to prevent such potential life-threatening emergencies are discussed.

A critique of bond strength testing in orthodontics

The literature contains a large number of publications on in vitro bond strength testing of materials used in orthodontics. The results are often quoted by manufacturers to support their products. Little attention has been paid to the detail of the test procedures used. However, a review of the literature revealed a large variation in the methods used for bond strength testing in orthodontics making comparison of papers difficult and often impossible. The case for a possible standard technique is suggested. It is hoped that this will lead to more meaningful testing of new products, which will produce more reliable guidance for the clinical orthodontist.

Villous adenoma of the common bile duct

A villous adenoma of the common bile duct (CBD) causing obstructive jaundice was demonstrated by sonography and ERCP in a 34-year-old man. The radiological and clinical features of this rare tumor are herein presented.

Late onset renal allograft anastomotic pseudoaneurysm with absent Doppler signal

A large extrarenal pseudoaneurysm, originating from the arterial anastomosis of a renal allograft, occurred spontaneously 7 years after transplantation in a 29-year-old diabetic patient. Although the scintigraphic examination was diagnostic of a pseudoaneurysm, pulsed Doppler and color coded Doppler ultrasound failed to demonstrate a Doppler signal, suggesting erroneously a nonvascular fluid collection. The role of scintigraphy combined with duplex ultrasound in this rare but potentially fatal complication of renal transplantation is discussed.

Hypoplastic superficial femoral artery associated with bilateral persistent sciatic arteries: a diagnostic pitfall

A patient with unsuspected bilateral persistent sciatic arteries (PSAs) underwent angiography following a gunshot wound to the right thigh. A hypoplastic superficial femoral artery associated with this rare vascular anomaly was misdiagnosed as being traumatically occluded. Pitfalls in the diagnosis of PSA as well as the embryology, clinical features, and complications are discussed.

Serendipitous scintigraphic detection of asymptomatic anastomotic pseudoaneurysms in human pancreatic allografts

Two cases of scintigraphically detected asymptomatic graft anastomotic pseudoaneurysms are reported. Both patients previously underwent simultaneous renal and pancreatic transplantation. The role of imaging in the diagnosis of this relatively rare, but potentially lethal, vascular complication of pancreatic transplantation is discussed. This is the first report of anastomotic pseudoaneurysms in pancreatic transplants being diagnosed by scintigraphy.

Submucous resection of the nasal septum as an outpatient procedure

We report our experience of submucous resection of the nasal septum under local anaesthesia as an outpatient procedure. We have audited 50 consecutive cases and compared the results with a similar group of patients in whom the operation was carried out in the usual way under general anaesthesia. We have found the procedure to be safe, effective and economically advantageous.

Does post-operative nasal packing cause nocturnal oxygen desaturation?

Previous studies have shown an increased frequency and duration of apnoeic episodes during sleep when the nose is occluded. The aim of this study was to ascertain whether oxygen desaturation occurs with nasal occlusion by post-operative packing. Continuous digital pulse oximetry was carried out before and after submucous resection of the nasal septum in 17 otherwise healthy patients. Post-operative nasal packing produced a statistically significant change in oxygen saturation during sleep. The change was, however, of such small magnitude that it is unlikely to be clinically significant.

Mid-line presentation of cervical lymphomata

Three cases of lymphoma are reported, all of which presented as a mid-line cervical swelling and appeared to be localised disease. The importance of early removal of such lesions is emphasized.

Unterberger stepping test: a useful indicator of peripheral vestibular dysfunction?

Deviation of gait in a stepping test has been proposed as a useful indicator of peripheral labyrinthine dysfunction. A prospective study of 26 patients suspected of having uncompensated peripheral labyrinthine dysfunction and 49 normal patients with normal labyrinthine dysfunction showed no significant difference in performance of the Unterberger stepping test between patients with electronystagmographically significant canal paresis and those with normal vestibular function.

Electrocochleography: a new technique

The near field monitoring of an auditory evoked response from the cochlear (electrocochleography) is a tried and trusted clinical tool. Conventional techniques for performing electrocochleography are cumbersome to use and frequently uncomfortable for the patient. We present a simple, modified technique which provides more flexibility with regard to where and when electrocochleography may be performed and also improves patient comfort during the test.

Adenoidal hypertrophy as the presenting feature of HIV infection

A case of symptomatic recurrent adenoidal hypertrophy, as the presenting feature of HIV infection in a haemophiliac child, is reported. The incidence of non-malignant nasopharyngeal lymphoid hyperplasia in HIV infection is examined and the relevance of the histological appearance is discussed in relation to progression of disease.

Total laryngotracheal hypoplasia in a case of G syndrome

We report a case of congenital hypoplasia of the larynx and trachea in the presence of an essentially normal cartilaginous structure. To our knowledge this abnormality is not recognised in the literature. Previously reported hypoplastic laryngeal anomalies have all shown anatomical defects ranging from clefts to atresia (Smith and Bain 1965, Gatti et al., 1987). Similarly total congenital tracheal stenosis is accompanied by abnormalities of the cartilaginous structure, usually complete tracheal rings. These types of anomaly typically present either at, or soon after, birth and are associated with other congenital abnormalities. In this particular case the laryngotracheal hypoplasia occurred in the context of a herditary condition of multiple congenital abnormalities known as G syndrome (also known as Opitz-Frias syndrome or the Opitz-G syndrome).

Kikuchi's disease--apparent malignancy of a neck mass

We report a case of Kikuchi's disease presenting as cervical lymphadenopathy in an adolescent. The original histological diagnosis in this case was a metastatic neoplasm. We wish to highlight the importance of this rare condition because of its potential for mimicking malignancy.