Biomedical subjects

Andrew Edwards

Publications and source records attributed to Andrew Edwards.

13 recordsLinked to original sources

PubMed2007

Double-bundle "anatomic" anterior cruciate ligament reconstruction: a cadaveric study of tunnel positioning with a transtibial technique.

PURPOSE: The aim of this study was to examine whether a double-bundle anterior cruciate ligament (ACL) reconstruction with a transtibial approach could position the tibial and femoral tunnels accurately in the native bundle attachments. METHODS: In 21 fresh-frozen knees the tibial and femoral attachments of the anteromedial (AM) and posterolateral (PL) bundles were outlined. The AM tibial tunnel guidewire was drilled with the 65 degree Howell tibial guide (Arthrotek, Warsaw, IN) located against the femur in the extended knee. The PL tibial wire was drilled through a prototype attachment to the Howell guide. Of the knees, 14 were available for the femoral part of the study. The AM femoral guidewire used an aimer offset 3 mm from the over-the-top position. The PL wire was drilled transtibially at 70 degrees of flexion, with external rotation and posterior drawer loads being applied. The plateaus and condyles were photographed and the wire positions measured. RESULTS: With regard to the tibia, 17 of 21 AM wires were in the AM bundle attachment (at 61% and 36% of the natural ACL posteroanterior and mediolateral length, respectively) and 19 of 21 PL wires were in the PL bundle attachment (at 28% and 36% of the posteroanterior and mediolateral length, respectively). With regard to the femur, 12 of 14 AM wires and 9 of 14 PL wires were in the correct native bundle attachment. The AM wire was 3% more shallow than the center of the AM attachment (P = .03) and 6% more superior (P < .001), where 100% was the diameter of the posterior lateral condyle. The PL wire was 4% more shallow than the center of the PL attachment (P = .026) and 6% more superior (P < .001). CONCLUSIONS: Anatomic and reproducible tibial guidewire positioning was achieved. Femoral wires were reproducibly positioned, but both were superior to and more shallow than the natural ACL bundle attachments, so further development or a different approach is appropriate. CLINICAL RELEVANCE: The double-bundle reconstruction aims to restore anterior drawer and rotational stability. This technique ensures anatomic tibial positioning. Further improvements are needed with regard to the femur.

Anterior Cruciate Ligament↗

PubMed2006

A single surgeon's experience of treatment of Lisfranc joint injuries.

This paper assesses the outcomes and complications of Lisfranc joint injuries treated at a regional trauma centre under the care of a single surgeon. We performed a retrospective study of all patients that underwent ORIF of a Lisfranc joint injury over a 5-year period. Case note review, radiology review, and questionnaire assessment were performed. We analysed for correlations between outcome and injury type, mechanism of injury, and presence of other ipsilateral limb injury and pure ligamentous injury. All injuries were classified according to a system described by Myerson et al. (Types A, B1, B2, C1, C2). Radiographs were also assessed for the presence of pure ligamentous injury. Outcome was measured using the American Orthopaedic Foot and Ankle society (AOFAS) midfoot score. Twenty-five injuries (24 patients) were identified and 16 injuries (15 patients) were available for follow. The mean duration of follow up was 42.6 months (11-69). The mean outcome score was 78.3 (38-100). The outcome scores for pure ligamentous injury (74.9) and for mixed bony and ligamentous injury (80.9) had no significant difference (p=0.61). High-energy trauma accounted for 50% of cases, and scored significantly less than low energy trauma (69.1 versus 87.4, p<0.05). There was an associated injury in the ipsilateral limb in 31% of cases and this group had a poorer outcome (63.0 versus 85.3, p<0.035). The most common injury type was B2 (38%). Type C2 injuries (divergent with total displacement) had a worse outcome than the mean outcome of all other categories (60.5 versus 84.4, p<0.01). Our mean outcome from ORIF of Lisfranc joint injuries is comparable to internationally quoted figures. Pure ligamentous injuries did no worse statistically than mixed bony and ligamentous injuries. Poorer outcome was associated with high-energy trauma, associated injury on the ipsilateral limb, and Type C2 injuries.

Adolescent↗

PubMed2006

Validation of the 65 degrees Howell guide for anterior cruciate ligament reconstruction.

PURPOSE: To study in cadaver knees the position of the tibial tunnel in anterior cruciate ligament (ACL) reconstruction using the 65 degrees Howell guide (Arthrotek, Ontario, CA). TYPE OF STUDY: Controlled laboratory study in vitro. METHODS: Twenty-one fresh-frozen cadaver knees were used. The ACL was resected and its tibial attachment was demarcated. To drill the guidewire, we used the Howell 65 degrees tibial guide, which references off of the intercondylar roof in extension to avoid impingement. The intra-articular position of the wire was digitized with a digital camera and referred to a transverse axis passing through the over-the-back position and a sagittal axis passing through the lateral aspect of the medial spine. The percentage position of the wire within the ACL attachment was also calculated, taking the posterior and medial limits as the 0% positions. RESULTS: All the wires were within the ACL attachment: 17 were in the ACL posterolateral bundle attachment and the other 4 in the anteromedial. The average distance of the wire from the transverse and sagittal axes was 12 mm (SD, 3 mm) anterior and 1 mm (SD, 1 mm) lateral, respectively. The wire was positioned at 38% (SD, 16%) of the length of the ACL attachment and at 40% (SD, 17%) of the width. Eighty percent of the wires were positioned at between 35% and 48% of the attachment length. CONCLUSIONS: The 65 degrees Howell guide, which positions the tibial tunnel in extension to avoid roof impingement, ensures anatomic positioning of the graft on the tibial side and reproducibility can be expected. CLINICAL RELEVANCE: This study proves that a commonly used drill guide succeeds in placing the ACL graft in the tibial anatomic attachment.

Anterior Cruciate Ligament↗

PubMed2006

Maternal serum activin A and the prediction of intrauterine growth restriction.

BACKGROUND: Differentiating between the small healthy fetus and the high risk growth restricted fetus remains a significant obstetric challenge. It has been previously shown that maternal activin A levels are increased in association with fetal growth restriction. AIM: To evaluate maternal serum activin A as a marker of fetal growth restriction. METHODS: Prospective cohort study of 62 women referred for fetal assessment because of a clinical suspicion of a small for gestation fetus. Maternal serum levels of activin A were measured with an ELISA. RESULTS: Activin A levels, expressed as median (95% CI) MoMs, were similar in the women with a normal-sized fetus and in those with a healthy small for gestational age fetus, 1.14 (95% CI 1.0-1.5) and 1.31 (95% CI 0.8-2.1), respectively (P = 0.97). Compared to the women with a normal-sized fetus or a healthy small fetus, activin A levels were significantly elevated in the women who had an intrauterine fetal growth restriction fetus 2.37 (95% CI 1.6-3.7; P = 0.01 compared to normal and P = 0.04 compared to healthy small). CONCLUSIONS: These data confirm that circulating activin A is increased in association with fetal growth restriction. However, a single blood sample for activin A will not efficiently discern between healthy and compromised small fetuses.

Activins↗

PubMed2005

Dissecting intramural haematoma of the oesophagus.

Dissecting intramural haematoma of the oesophagus (DIHO) is a rare condition, which has an excellent prognosis when managed conservatively. Awareness of this condition is vital to guide subsequent investigations and avoid inappropriate treatment or unnecessary surgical intervention. We describe an unusual case of massive DIHO causing left atrial compression presenting with pericarditic electrocardiographic changes and document the utility of endoscopic ultrasound/computed tomography to make the diagnosis.

Adult↗

PubMed2005

Acoustic streaming in ovarian cysts.

OBJECTIVE: The purpose of this study was to investigate the hypothesis that endometriomas do not show acoustic streaming and then to quantify the streaming velocity of the particles within ovarian cysts that do show acoustic streaming. METHODS: Ovarian cysts greater than 2 cm in diameter, with internal echoes seen on B-mode sonography, were prospectively evaluated for the presence of acoustic streaming. If acoustic streaming was present, a 2-mm pulsed Doppler sample volume was then placed within the distal portion of the cyst, and the streaming velocity was recorded. Follow-up included review of subsequent sonographic examinations, surgical notes, and histopathologic reports, with the latter being considered the final results if available. RESULTS: Acoustic streaming was detected in 10 (38%) of 26 ovarian cysts, but of the 10 endometriomas, none (0%) showed acoustic streaming (P = .002). Acoustic streaming was detected in 86% (n = 6) of cystadenomas. Four of these were serous cystadenomas, which all showed acoustic streaming, with a velocity range of 1.5 to 3.6 cm/s. Two mucinous cystadenomas showed acoustic streaming with velocities of 0.8 and 2.0 cm/s. CONCLUSIONS: Endometriomas appear as cysts containing homogeneous, low-level, "ground glass" echoes on gray scale sonography. Other types of ovarian cysts can also have these appearances. Endometriomas do not show acoustic streaming. Cystadenomas may have streaming velocities within a defined range. Acoustic streaming assessment may therefore prove to be an additional useful tool in assessing ovarian cysts and in completely excluding endometrioma as a diagnosis if a cyst shows acoustic streaming.

Adolescent↗

PubMed2004

Acoustic streaming: an in vitro study.

The aims of this study were, first, to determine if cyst size and cyst-to-transducer distance have an impact upon acoustic streaming and, second, to investigate the effect of cyst content viscosity on acoustic streaming using an artificial ovarian cyst model. Artificial ovarian cysts were constructed and suspended in a tissue-mimicking bath. Although there was no subjective difference in acoustic streaming velocity between cyst sizes during B-mode insonation, with colour Doppler and pulsed Doppler examination, higher acoustic streaming scores were recorded for larger cysts. When the cyst-to-transducer distance was increased, the acoustic streaming velocity was noted to decrease in all scanning modalities. The second stage of the study demonstrated decreasing acoustic streaming velocity as the viscosity of the cyst content was increased. The finding of a clear association between cyst content viscosity and acoustic streaming velocity raises the exciting possibility that we may be able to make estimations of the viscosity of ovarian cyst contents, in the clinical setting, by sonographic means.

Body Fluids↗

PubMed2003

The effect of image size on nuchal translucency measurement.

OBJECTIVES: To assess the effect of altering image size on the absolute nuchal translucency (NT) measurement. METHODS: NT was measured at three image magnifications (60%, 100% and 200%) in 120 singleton pregnancies. RESULTS: The mean +/- SD NT measurements were 1.52 +/- 0.57 mm, 1.35 +/- 0.53 mm and 1.18 +/- 0.48 mm at 60%, 100% and 200% magnification, respectively (p = 0.00001). CONCLUSIONS: The measurement of NT decreases significantly with increasing image size. Optimisation of NT as a method of screening will require agreed standardisation of image magnification.

Adolescent↗

PubMed2003

Betamethasone associated changes in umbilical artery flow velocity waveforms in multiple pregnancies with umbilical artery absent end diastolic flow.

OBJECTIVES: It has been previously shown that glucocorticoids alter umbilical artery flow velocity waveforms in singleton pregnancies complicated by umbilical artery absent end diastolic flow. Whether similar effects are evident in multiple pregnancies where one fetus has umbilical artery absent end diastolic flow is not known. METHODS: Women with a twin or triplet pregnancy complicated by umbilical artery absent end diastolic flow in one fetus were admitted to hospital for intensive fetal surveillance including daily umbilical artery flow velocity waveform studies, as per hospital protocol. All women received prophylactic betamethasone (11.4 mg x 2, 24 h apart) in anticipation of preterm delivery. RESULTS: Between October 1996 and February 2002, 24 women with a multiple pregnancy complicated by umbilical artery absent end diastolic flow were cared for. Of these, six had a pregnancy with feto-fetal transfusion and excluded from further analysis. Of the remaining 18 women, eight had monochorionic diamniotic twins, eight had dichorionic twins, and two had trichorionic, triamniotic triplets. The median (range) gestation at diagnosis of umbilical artery absent end diastolic flow was 210.5 days (173-241). In nine (50%) of the 18 pregnancies the administration of betamethasone was associated with return of umbilical artery end diastolic flow for a median of 5 days. There was no association between this effect and chorionicity. The median (range) interval from diagnosis of umbilical artery absent end diastolic flow to delivery was 11 days (1-46). CONCLUSIONS: As previously reported in singleton pregnancies, the maternal administration of betamethasone in multiple pregnancies with umbilical artery absent end diastolic flow is associated with a transient return of end diastolic flow.

Betamethasone↗

PubMed2003

Changes in umbilical artery flow velocity waveforms following maternal administration of betamethasone.

In a retrospective cohort study we have previously shown that administration of betamethasone to women with a pregnancy complicated by absent end-diastolic flow in the umbilical artery (UA) is associated with altered UA flow velocity waveforms. To examine this phenomenon further we undertook a prospective study of 30 similar singleton pregnancies. Umbilical artery FVWs were recorded before and after betamethasone administration using real-time pulsed wave colour flow Doppler. The results of this prospective cohort were similar to those of the retrospective study allowing pooling of the data. Of the 55 total pregnancies with umbilical artery AEDF studied betamethasone administration was associated with the return of end-diastolic flow in 39 (71 per cent; 95 per centCI: 59-83 per cent). The median (range) duration of this change was 3 (1-10) days. There is no evidence that this change has either a beneficial or detrimental effect on foetal health. Administration of betamethasone to women with a pregnancy complicated by umbilical artery AEDF is associated with the transient return of end-diastolic flow in most cases. While the mechanisms underlying this effect are yet to be fully elucidated it has implications for foetal surveillance in these high-risk pregnancies.

Adult↗

PubMed2003

Maternal serum activin A levels in association with intrauterine fetal growth restriction.

OBJECTIVE: To assess maternal serum activin A as a potential marker of fetal growth restriction. DESIGN: A cohort study. SETTING: A maternal-fetal medicine unit, university teaching hospital. POPULATION: Fifty-seven women with a small fetus (less than 10th centile for gestation) referred for assessment of fetal size by ultrasound biometry. METHODS: At the time of presentation for fetal biometry, maternal blood was collected for activin A measurement. The case records of each woman were independently reviewed after delivery and the pregnancy grouped into one of three groups: constitutionally small fetus, intrauterine growth restricted (IUGR) fetus or IUGR fetus and maternal pre-eclampsia (IUGR-pre-eclampsia). Activin A levels in the three groups were compared. MAIN OUTCOME MEASURES: Maternal serum activin A levels. RESULTS: Sixteen of the 57 pregnancies were classified as constitutionally small, 17 as IUGR and 24 as IUGR-pre-eclampsia. Expressed as multiples of a normal median (MoMs), the median (95% CI) activin A level in the constitutionally small pregnancies was 1.12 (0.72-1.39) MoMs significantly lower than the level in both the IUGR pregnancies, 3.00 (1.84-4.11) MoMs, and the IUGR-pre-eclampsia pregnancies, 7.96 (5.73-10.62) MoMs (P = 0.002 and 0.0001 for IUGR vs constitutionally small and IUGR-pre-eclampsia vs constitutionally small, respectively). CONCLUSIONS: Maternal serum activin A may be useful in the assessment of the small for gestational age fetus.

Activins↗

PubMed2002

Optimising the timing for nuchal translucency measurement.

It appears from current evidence that the most effective screening strategy for Down syndrome will involve a combination of first trimester nuchal translucency and serum biochemistry, whether performed in the first or second trimester. The aim of this study was to determine the optimum gestation based upon menstrual dates at which to schedule nuchal translucency (NT) measurement for the evaluation of fetal Down syndrome risk. Five thousand eight hundred and thirty-five pregnancies had an ultrasound scan scheduled between 11 and 14 completed weeks of gestation based upon either the last menstrual period (n = 3199) or a prior ultrasound scan (n = 2636). For last menstrual period-based ultrasound scans, with advancing gestation the frequency of missed miscarriage significantly decreased (p = 0.009, chi squared test), as did the need to reschedule a further scan because the gestation of the scheduled scan was too early to measure NT (p < 0.0001, Chi-squared test). In contrast, with advancing gestation the rate of unsuccessful NT measurement because the crown-rump length (CRL) was greater than 84 mm significantly increased (p < 0.0001, Chi-squared test). Of the women who had had an earlier ultrasound, 42 (1.6%) had a missed miscarriage and 9 (0.3%) were over gestation at the time of the NT scan. These data suggest that when only the last menstrual period is known the optimum time to schedule a nuchal translucency measurement is at 12 to 13 weeks' gestation.

Adult↗

PubMed2002

Phalen's test with carpal compression: testing in diabetics for the diagnosis of carpal tunnel syndrome.

Phalen's test with carpal compression is a reliable clinical test for the diagnosis of carpal tunnel syndrome. Along with classical clinical symptoms and positive clinical tests there may be no need to perform additonal electrodiagnostic studies, thus saving time and money. However, in the diabetic population this test has been shown to be a less reliable clinical tool in the diagnosis of carpal tunnel syndrome. Therefore, Phalen's test with carpal compression is not a predictive indicator of carpal tunnel syndrome in the diabetic population.

Adolescent↗