Iain R. Mackay

A direct comparison of pulsed dye, alexandrite, KTP and Nd:YAG lasers and IPL in patients with previously treated capillary malformations

Several studies have reported laser treatment of Capillary Malformations (CMs) using systems other than pulsed dye lasers (PDL). Few, however, have compared different systems in the same patients. This study aimed to directly compare CM fading using five different systems.

The effect of varying pulse duration, wavelength, spot size, and fluence on the response of previously treated capillary vascular malformations to pulsed-dye laser treatment.

Modern lasers allow different parameters to be altered in an effort to gain further improvement in otherwise resistant capillary vascular malformations (CMs). The aim of this study was to examine the effect of changing the pulse duration, wavelength, spot size, and fluence on the color and capillary architecture of 585-nm pulsed-dye, laser-resistant CMs. Eighteen patients were assessed with a depth measurement videomicroscope (DMV) before and after 12 test patches with ScleroPlus and V-Beam lasers at specified parameters. In the majority of the test patch areas, there was little improvement after treatment. However, 44% of patients had greater than 75% clearance in at least 1 test patch site. This study demonstrates that both lasers can achieve further lightening in 585 nm 0.45 msec pulsed-dye laser-resistant CMs. However, in CMs consisting of small-diameter deep vessels, further improvement is unlikely.

Q-switched ruby laser in the treatment of labial melanotic macules

The term, labial melanotic macule, refers to a benign entity. The Q‐switched ruby laser (QSRL) has been used to treat such lesions but the numbers are small with relatively short follow‐up.

Effects of perforator number and location on the total pedicle flow and perfusion of zone IV skin and fat of DIEP flaps

BACKGROUND DIEP flaps are a popular choice for autologous breast reconstruction, though many surgeons routinely discard zone IV, limiting transferrable tissue. We investigated the effect of altering number and location of perforators supplying the flap on total pedicle flow and perfusion of skin and fat of zone IV. METHODS 20 cranially-based abdominal epigastric perforator flaps were raised in rats on two perforators. The perforators were sequentially clamped and released in a randomised order and total pedicle flow measured using microvascular flow-probes, on the following perforator combinations: 13 DIEP flaps were raised in post-mastectomy patients requiring breast reconstruction on two perforators. These were clamped and released as before to assess perfusion of fat and skin in zone IV using SPY indocyanine-green-fluorescence-angiography scans on the same perforator combinations as in our animal study, listed above. RESULTS All data were analysed using 2-way-ANOVA and revealed that vascular flow was significantly (p < 0.0001) greater on one perforator as opposed to two. These results were supported by our human study, revealing both zone IV fat and skin perfusion were significantly (p < 0.0001) greater when a single perforator was used. CONCLUSIONS Our data suggests total pedicle flow and perfusion of zone IV fat and skin is significantly higher on a single perforating blood vessel as opposed to two. Reasons for these observed differences could be due to changing pressure gradients across a piece of tissue prone to venous congestion, with maintenance of flow better in a single lumen.

Closed Rush pinning of fractures of the humeral shaft

Twenty-three simple and pathological fractures of the shaft of the humerus were treated by insertion of a Rush pin through the greater tuberosity, without exposing the fracture site. An image intensifier was used during the insertion of the pins. This technique results in few complications with simple fractures, and in pathological fractures relief of pain can be achieved without exposing the fracture site or surrounding soft tissues, which are often diseased.

Capillary vascular malformation response to increased ambient temperature is dependent upon anatomical location

Background:It has been documented that capillary malformations (CMs) located on the limbs tend to respond less well to laser treatment than those sited on the head and neck. However, there is little evidence available to explain this observation. Objectives:To investigate potential differences between CMs located on the head and neck with those on the limbs, by comparing their response to increasing ambient temperature. Methods:Fifteen previously untreated subjects with CMs were compared as the ambient temperature was increased from 20°C to 28°C. These included 10 with head and neck CMs and 5 with limb CMs. The following measurements were taken at 2°C intervals: cutaneous blood flow, capillary diameter, density and depth, CM color, skin and core temperatures. Results:There were no statistically significant differences in mean capillary depth, diameter, density, or CM color between groups. Cutaneous blood flow increased with ambient temperature in the head and neck CMs (P = 0.009) and was significantly higher than that in the limb CMs at all temperatures (P < 0.001), while the limb CMs did not demonstrate any increase in cutaneous blood flow with temperature. Conclusions:These results suggest a possible reason for the poorer response to laser treatment seen in limb CMs: since cutaneous blood flow is a product of the blood flow velocity and hemoglobin concentration, malformations with lower blood perfusion would have less chromophore available and therefore be less suitable for laser destruction.

Determining reactive hyperaemia time in Deep Inferior Epigastric perforators after temporary occlusion to allow the intraoperative comparison of vascular territories

Studies comparing the vascular territories of vessels to a flap, for example the DIEP and SIEA vessels in the lower abdomen, involve the sequential occlusion of vessels. By clamping, unclamping and reclamping, the vascular territories of each individual vessel can be compared. Microvascular studies describe a blood flow ‘stabilisation’ period of 10 min or longer after releasing the vessel clamp, before assessing a vessel using methods including laser Doppler, indocyanine green, videoangiography, tissue spectrophotometry and near-infrared. This period of reperfusion is ill defined and is of importance in intra-operative studies assessing multiple vessels in free flap transfer. The lower abdominal skin and Deep Inferior Epigastric Perforator (DIEP) flap was used as a model in this feasibility study, designed to clarify effects of different microvascular clamp times, and laser doppler scanning times following clamp release, to define the period of reactive hyperaemia, with a view to subsequently investigating physiological territories of vessels using intra-operative studies. Knowledge of these parameters would allow the design of further intraoperative studies and maximise the information gathered within operative time constraints. Eight patients undergoing breast reconstruction with DIEP flaps were recruited. A Laser Doppler Scanner LDI2eIR (Moor Instruments, UK) was used to non-invasively measure blood flow to the skin of the DIEP flap intraoperatively before flap transfer. The DIEP flap was raised on perforating vessels chosen by the surgeon. The patients were split into two groups; four patients had a clamp time of 5 min with laser doppler scans performed at 5, 10 15 and 20 min after clamp release, and four patients had a clamp time of

Microdialysis as a Method of Investigating Factors Controlling Microcirculation Following Free Flap Transfer.

MATERIALS AND METHODS: Eleven patients undergoing DIEP flap breast reconstruction were recruited for this pilot study. Microdialysis catheters with specialised ‘high cut-off’ membranes for the collection of larger molecules were chosen to measure changes in tissue fluid in DIEP flaps, a technique not previously reported in free flaps. Three catheters per patient were inserted intraoperatively into Hartrampf4,5 DIEP zones 1, 2 and 4. Microdialysis continued for 72 hours with dialysate collected every 4 hours. Initial analysis was performed as planned on a subset of six of the eleven patients as part of an investigative phase. ELISA kits were used to detect human interleukin-6, fibroblast growth factor and tumour necrosis factor alpha.

Developments in the videomicroscopic assessment of capillary vascular malformations

The use of pulsed dye laser for the treatment of Capillary Vascular Malformations (CVMs) only leads to complete clearing of the abnormality in a minority of cases. In order to examine the characteristics of a CVM, which determine its response to laser treatment, we have used videomicroscopy. By using a videomicroscope to determine the vessels diameters within a CVM in-vivo it is hoped that treatment parameters can be chosen which would be most appropriate to achieve the best response. To increase the clarity of our images and reduce reflection we carried out a videomicrographic examination using both normal white light and green filtered light on 24 sites on 18 patients. For the deeply placed reticular vessels we found no difference between the results obtained with the two techniques. However, for the superficial papillary vessels we found a statistically significant (p < 0.01) increase in the recordings taken with the green filtered lens. We attribute this difference to the reduction in reflection seen with the green filter. We have also developed a depth measuring videomicroscope, which allows the calculation of vessel depth as well as vessel diameter.