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Biomedical subjects

V C Lees

Publications and source records attributed to V C Lees.

At least 19 recordsLinked to original sources
PubMed2006

Contact area inside the distal radioulnar joint: effect of axial loading and position of the forearm.

BACKGROUND: A biomechanical study was performed to define the normal profiles of contact area inside the distal radioulnar joint and how these profiles change as a result of damage to the distal radioulnar ligaments. METHODS: Twelve cadaver arms were used and a custom-made jig was designed to allow axial loading of the hand. Tekscan sensor film was used to measure the contact area inside the joint. Measurements were taken with different loads and in different positions of the forearm. The same measurements were taken after dividing either the volar or dorsal distal radioulnar ligament. Finally the measurements were repeated after reconstruction of the divided ligament. FINDINGS: The contact area increases with axial loading of the hand and is greater in supination than pronation. Division of a single distal radioulnar ligament increases the contact area inside the distal radioulnar joint (123% of normal) and reconstruction of the divided distal radioulnar ligament restores the contact patterns towards the normal values (113% of normal). INTERPRETATION: The results show that axial loading of the hand and position of the forearm has a significant effect on the contact area inside the distal radioulnar joint. The study also shows that injury of the distal radioulnar ligament disturbs the normal profiles of contact.

Aged↗
PubMed2006

Aesthetic surgical training in the UK independent sector--the clients' view: Results of a survey on 155 private patients.

As training opportunities in cosmetic surgery become less frequent in teaching hospitals, this survey set out to examine the attitudes of patients towards extending this training into the independent health sector. We questioned 155 private patients, 95% of who were happy for trainees to sit in during their consultations. Of these, 85% were comfortable with the presence of the trainee throughout their appointments and 92% said they saw advantages in having such trainees present. However, patients were less enthusiastic about trainees carrying out procedures, under consultant supervision and for a reduced fee. The survey found that while 49% felt it was a good idea, only 32% would consider it for themselves. Seventeen percent of patients thought this offer alone was inappropriate. This survey has shown that while the vast majority of private patients supported and were happy to participate in higher surgical training during private consultations, fewer would consider the possibility of cosmetic surgery performed by supervised trainees for reduced fees. The implications of these findings for higher surgical training in Plastic Surgery in the UK are discussed.

Adolescent↗
PubMed2006

The load-bearing characteristics of the forearm: pattern of axial and bending force transmitted through ulna and radius.

A biomechanical study was performed on 12 cadaveric arms to define the normal profiles of force transmission through the ulna and radius and demonstrate the effect on these of simulated injury of the distal radioulnar joint (DRUJ). Strain gauges were used to measure the axial and bending forces transmitted through each bone. Axial force transmitted through the ulna is, broadly, reciprocal to that seen in the radius, with the greatest force seen in supination. In all 12 arms, axial loading of the hand created an anterior bending force (to create a posterior convexity) in the distal radius. Axial loading of the hand created an anterior bending force in the distal ulna for half the specimens and a posterior bending force in the remaining half. Division and division with reconstruction of either the volar or the dorsal distal radioulnar ligament (DRUL) had no significant effect on force transmission through the ulna and radius, while excision of the ulnar head significantly disrupted the profiles of the axial and bending forces.

Aged↗
PubMed2005

The two parts of the dorsal radiocarpal (radiolunotriquetral) ligament.

An anatomical study was performed to identify the configuration of the dorsal radiocarpal ligament. Fourteen fresh frozen wrists from seven cadavers (mean age 65 years) were dissected under loupe magnification. The study demonstrates that the dorsal radiocarpal ligament had, in every case examined, an additional superficial component which has not been previously described. It arises from the distal part of the interosseous border of the radius. It runs obliquely, distally and ulnarward, over the distal ulna to attach to the lunate and triquetrum. The dorsal radiocarpal ligament blends with the underlying dorsal radioulnar ligament which runs transversely, at a deeper plane, between the radius and ulna. The paper discusses the clinical implications of this finding.

Cadaver↗
PubMed2004

An evaluation of the influence of practitioner-led hand clinics on rupture rates following primary tendon repair in the hand.

Practitioner-led hand clinics were introduced in our unit in the year 2000 as a response to the high and increasing number of postoperative hand trauma patients coming to consultant clinics. The aim of this study was to evaluate the influence of these clinics on rupture rates following primary tendon repair in the hand. The study specifically examined:zone II flexor tendon repairsflexor pollicis longus (FPL) tendon repairsextensor pollicis longus (EPL) tendon repairs. Prospective data collection were undertaken for these particular operations over a 17-month study period. Prior to the introduction of the practitioner-led hand clinics previous audits had demonstrated rupture rates of 30% zone II flexor tendon repairs, 16% for FPL repairs and 5% for EPL repairs. Rupture rates after the introduction of practitioner-led hand clinics fell in all of the study categories-to 17% for zone II flexor tendon repairs, 4% for FPL repairs and 0% for EPL repairs. It is suggested that improved continuity of care by experienced hand therapists may have contributed to the observed improvements in outcome.

Adult↗
PubMed2003

Efficacy of ADCON-T/N after primary flexor tendon repair in Zone II: a controlled clinical trial.

A prospective double-blind, randomized, controlled clinical trial was conducted to assess the use of ADCON-T/N after flexor tendon repair in Zone II. Forty-five patients with 82 flexor tendon repairs in 50 digits completed the study. ADCON-T/N was injected into the tendon sheath after tenorrhaphy in the experimental group while the control group was not treated with ADCON-T/N. ADCON-T/N had no statistically significant effect on total active motion at 3, 6 and 12 months but the time taken to achieve the final range of motion was significantly shorter in treated patients. ADCON-treated patients had a higher rupture rate but this was not significant.

Adult↗
PubMed2003

A biomechanical study of reattachment versus distal multistrand repair in distal division of the flexor digitorum profundus.

Distal division of the flexor digitorum profundus (FDP) within 10mm of its insertion is commonly treated in the same manner as avulsion of the FDP, using the "button" technique or bone suture anchor fixation. Button and bone suture anchor fixation techniques have been associated with significant complications. Importantly, both lead to shortening of the FDP which may cause flexion contracture at the distal interphalangeal joint. This study compared the breaking strength of a multistrand distal suture with reattachment using the "button-on-the-nail" technique in a laboratory cadaver model of distal FDP division. The data showed that multistrand distal suture repair was at least as strong as reattachment and has the theoretical advantage of avoiding some of the acknowledged complications of reattachment techniques.

Biomechanical Phenomena↗
PubMed2003

Lessons learned from the management of complex intra-articular fractures at the base of the middle phalanges of fingers.

The use of dynamic traction splintage is established in the treatment of complex intra-articular phalangeal fractures. Several different systems have been used and we report our experience with one of these, the Pins and Rubber Traction System. A cohort of 14 patients with complex intra-articular fractures at the base of the middle phalanges of the fingers were treated and assessed prospectively over a 2.5-year period (mean, 20 months; range, 7-28 months). The mean active range of motion regained, at the proximal interphalangeal joint, was 74 degrees (range, 0-100 degrees ). The mean total active motion of the injured digit was 196 degrees (range, 40-275 degrees ). Refinements in the regime are suggested as a result of this investigation.

Adolescent↗
PubMed1999

Successful revascularization of subtotal amputation of a digit in a neonate.

A successful revascularization was performed in a neonate who sustained a subtotal amputation of the right ring finger with cord scissors while the umbilical cord was being cut. Successful revascularization of the digit was achieved within 5 hours of the injury using standard microsurgical techniques.

Amputation, Traumatic↗
PubMed1998

The surgical management of the upper extremity anomalies associated with Du Pan syndrome.

Du Pan syndrome is a rare condition comprising complex brachydactyly with fibular hypoplasia that is inherited in an autosomal recessive manner. This article describes experience gained through the management of four patients with this disorder. The surgical management of the upper limb abnormalities is discussed and a detailed timetable for their treatment is suggested.

Abnormalities, Multiple↗
PubMed1995

Thymidine phosphorylase is angiogenic and promotes tumor growth.

Platelet-derived endothelial cell growth factor was previously identified as the sole angiogenic activity present in platelets; it is now known to be thymidine phosphorylase (TP). The effect of TP on [methyl-3H]thymidine uptake does not arise from de novo DNA synthesis and the molecule is not a growth factor. Despite this, TP is strongly angiogenic in a rat sponge and freeze-injured skin graft model. Neutralizing antibodies and site-directed mutagenesis confirmed that the enzyme activity of TP is a condition for its angiogenic activity. The level of TP was found to be elevated in human breast tumors compared to normal breast tissue (P < 0.001). Overexpression of TP in MCF-7 breast carcinoma cells had no effect on growth in vitro but markedly enhanced tumor growth in vivo. These data and the correlation of expression in tumors with malignancy identify TP as a target for antitumor strategies.

Animals↗
PubMed1995

Angiogenesis in a delayed revascularization model is accelerated by angiogenic oligosaccharides of hyaluronan.

BACKGROUND: A delayed revascularisation model has been used to assess the angiogenic activity of hyaluronan fragments on impaired wound healing. EXPERIMENTAL DESIGN: Revascularisation of single, full thickness skin autografts in rats was delayed by subjecting isolated grafts to a sublethal cryoinjury (freeze injury) before implantation. Hyaluronan fragments were delivered to the grafts using slow release pellets (ethylene vinyl acetate copolymer). Rates of release were measured in vitro by ELISA. The angiogenic response to the application of 100 micrograms of low (1 to 4 kDa) molecular weight hyaluronan and 100 micrograms of medium (33 kDa) molecular weight hyaluronan was tested in separate groups of 15 rats and was compared with unstimulated cryoinjured controls (n = 40). The effect of low (1 to 4 kDa) molecular weight hyaluronan on uninjured grafts was also investigated. Return of graft blood flow was measured on anesthetised animals over a 10-day period using laser Doppler flowmetry and 133Xe clearance. Quantitative histologic assessment of the graft vasculature was performed on Days 3, 7, and 10 after implantation. RESULTS: The 1- to 4-kDa hyaluronan fragments increased blood flow (p < 0.001), as measured by both flow measuring techniques, and increased graft vessel growth, as assessed histologically at each of the three time points (p < 0.05). By contrast, the 33-kDa fragments had no such effect on graft blood flow or vessel growth. Low molecular weight hyaluronan had no effect on either graft blood flow or on vessel growth in uninjured skin grafts. CONCLUSIONS: The hypothesis that there may be physiologic regulation of angiogenesis by hyaluronan and its metabolites is supported by the results of these studies. The data provide further evidence of the utility of the cryoinjured graft model for the study of in vivo angiogenesis.

Animals↗
PubMed1994

A freeze-injured skin graft model for the quantitative study of basic fibroblast growth factor and other promoters of angiogenesis in wound healing.

A new in vivo model has been developed for the quantitative study of promoters and potential promoters of angiogenesis. Full thickness rat skin autografts received a reproducible and uniform freeze injury, before being applied to full thickness wounds, in order to delay revascularisation. Blood flow in the grafts was measured during the healing period using noninvasive (laser Doppler flowmetry) and invasive (133Xe clearance) techniques. The increase in blood flow over a period of 10-14 days was taken as an index of angiogenesis. These measurements were corroborated by histological assessment of the graft vasculature, using a laminin stain to highlight vascular basement membrane. Freeze injury delayed but did not ultimately prevent full graft revascularisation (p < 0.01 for laser Doppler flowmetry and 133Xe clearance). Application of the angiogenic agent basic fibroblast growth factor (bFGF), in slow release pellet form, stimulated angiogenesis in cryoinjured grafts in a dose-related fashion. Doses of 500 and 5000 ng bFGF produced significant stimulation (500 ng bFGF, p < 0.001, and 5000 ng bFGF, p < 0.01, for both laser Doppler flowmetry and 133Xe clearance; increased vessel profile counts, p < 0.05, at each time point tested for both doses) while 50 ng bFGF had no significant effect. By contrast, 500 ng bFGF had no measurable effect on uninjured grafts. In addition, bFGF-stimulated angiogenesis in cryoinjured grafts was antagonised by a neutralising antibody to bFGF, demonstrating the specificity of action of bFGF in this model.

Animals↗
PubMed1994

A prospective investigation of the healing of grafted pretibial wounds with early and late mobilisation.

The aims of this study were to determine whether early mobilisation delays wound healing after meshed split skin graft repair of pretibial wounds and to identify other factors delaying the healing of these wounds. A prospective randomised controlled trial was conducted to compare the time to complete healing of patients mobilised early (the first postoperative day) against those who mobilised late (the tenth postoperative day). There was no difference in time to complete healing. Patients with a history of oral steroid therapy had a mean delay in wound healing of approximately 8 days (p < 0.02). The severity of tissue damage, as indicated by undermining of the skin margins, damage to the fascia and exposure of the periosteum, correlated with delayed wound healing (p < 0.05).

Aged↗