The influence of local and systemic preconditioning on oxygenation, metabolism and survival in critically ischaemic skin flaps in pigs

Stress proteins represent a group of highly conserved intracellular proteins that provide adaptation against cellular stress. The present study aims to elucidate the stress protein-mediated effects of local hyperthermia and systemic administration of monophosphoryl lipid A (MPL) on oxygenation, metabolism and survival in bilateral porcine random pattern buttock flaps. Preconditioning was achieved 24h prior to surgery by applying a heating blanket on the operative site (n = 5), by intravenous administration of MPL at a dosage of 35 microg/kg body weight (n = 5) or by combining the two (n = 5). The flaps were monitored with laser Doppler flowmetry, polarographic microprobes and microdialysis until 5h postoperatively. Semiquantitative immunohistochemistry was performed for heat shock protein 70 (HSP70), heat shock protein 32 (also termed haem oxygenase-1, HO-1), and inducible nitrc oxide synthase (iNOS). The administration of MPL increased the impaired microcirculatory blood flow in the proximal part of the flap and partial oxygen tension in the the distal part by approximately 100% each (both P<0.05), whereas both variables remained virtually unaffected by local heat preconditioning. Lactate/pyruvate (L/P) ratio and glycerol concentration (representing cell membrane disintegration) in the distal part of the flap gradually increased to values of approximately 500 mmol/l and approximately 350 micromol/l, respectively (both P<0.01), which was substantially attenuated by heat application (P<0.01 for L/P ratio and P<0.05 for glycerol) and combined preconditioning (P<0.01 for both variables), whereas the effect of MPL was less marked (not significant). Flap survival was increased from 56% (untreated animals) to 65% after MPL (not significant), 71% after heat application (P<0.05) and 78% after both methods of preconditioning (P<0.01). iNOS and HO-1 were upregulated after each method of preconditioning (P<0.05), whereas augmented HSP70 staining was only observed after heat application (P<0.05). We conclude that local hyperthermia is more effective in preventing flap necrosis than systemic MPL administration because of enhancing the cellular tolerance to hypoxic stress, which is possibly mediated by HSP70, whereas some benefit may be obtained with MPL due to iNOS and HO-1-mediated improvement in tissue oxygenation.

Architecture of European plastic surgery

The architecture of European Plastic Surgery was published in 1996 [Nicolai JPA, Scuderi N. Plastic surgical Europe in an organogram. Eur J Plast Surg 1996; 19: 253-256.] It is the objective of this paper to update information of that article. Continuing medical education (CME), science, training, examination, quality assurance and relations with the European Commission and Parliament all are aspects covered by the organisations to be discussed.

Improved skin flap survival after local heat preconditioning in pigs

BACKGROUND

Preconditioning induces the expression of heat shock proteins (HSPs), which can help a cell survive an acute episode of stress. Similar to the induction of HSP expression, the cell protection is independent of the type of stress. The aim of this study was to test in a large, randomized animal model, if skin flap survival may be improved by local heat preconditioning and induction of HSP 70.

MATERIALS AND METHODS

Twenty-four hours before surgery, a heating blanket was laid on the buttocks of large white pigs. In the preconditioned group (n = 6), the blanket was warmed up to 43 degrees C for 3 x 30 min, whereas it was kept at room temperature in between the heating episodes as well as in the control animals (n = 6). A random pattern skin flap was raised on both sides of the buttocks. Flap survival was measured clinically. Induction of HSP and apoptosis were assessed quantitatively by immunohistochemistry and TUNEL assay, respectively.

RESULTS

Preconditioning reduced flap necrosis from 40 +/- 8% of the total flap surface to 7 +/- 14% (P < 0.01). Induction of HSP was significantly higher in the experimental group (79 +/- 12% versus 42 +/- 13%, P < 0.01), whereas apoptosis in healthy flap tissue was reduced from 30 +/- 11 to 11 +/- 6 cells/visual field (P < 0.01).

CONCLUSION

In the present study, necrosis and apoptosis rate of skin flaps could be reduced significantly due to local heat preconditioning. Our results suggest that ischemia-related wound healing complications could be diminished with local heat application, a most simple and least invasive method of preconditioning.

Morbidity and outcome after sentinel lymph node dissection in patients with early-stage malignant cutaneous melanoma

OBJECTIVE

Prospective analysis of the morbidity and outcome of the sentinel lymph node (SLN) technique in a consecutive series of patients with early-stage melanoma.

METHODS

Between 1997 and 1998, 60 patients with stage IB-II malignant melanoma underwent SLN dissection. Preoperative dynamic lymphoscintigraphy with mapping of the lymph vessels and lymph nodes and location of the sentinel node was performed the day before SLN dissection. SLN was identified by use of the blue dye technique. SLN was assessed for histopathological and immunohistochemical examination. Postoperative morbidity and mortality were recorded. Follow-up consisted of repetitive clinical examination with lymph nodes status, laboratory and radiologic findings.

RESULTS

Tumor-positive SLN was observed in 18% of the patients and stage II disease was found in 91% of the patients with positive SLN. Breslow thickness was the only significant factor predicting involvement of a SLN (p = 0.02). In 36% of the positive SLN, metastases could be assessed only by immunohistochemical examination. Postoperative complications after SLN dissection were observed in 5% in comparison with 36% after elective lymph node dissection. After a mean follow-up of 32 months, recurrence was observed in 3% with a mean disease-free survival of 8 months. Overall survival was 82% and 90% in patients with positive and negative SLN, respectively. Overall mortality was 15%, due to distant metastases in 78% of the cases.

CONCLUSIONS

Staging of early-stage melanoma with the SLN dissection by use of the blue dye technique combined to lymphoscintigraphy and immunohistochemistry is reliable and safe, with less morbidity than elective lymphadenectomy. Long-term follow-up is mandatory to establish the exact reliability of SLN dissection.

Squamous cell carcinoma of the penile skin in a neovagina 20 years after male-to-female reassignment

We present a patient who underwent male-to-female reassignment, and then developed squamous cell carcinoma during a complicated long-term follow-up. In very rare cases, squamous cell carcinoma may be considered in the differential diagnosis of sustained ulceration in neovaginas constructed by inverting the penile skin in male-to-female reassignments, in particular because clinical examination may be hampered by contractile scar formation of the neovaginal canal. Despite the lack of statistical evidence, it may be assumed that the heterotopic penile skin is at an increased risk of developing HPV-induced squamous cell carcinoma, especially if, over the years, there is a personal history of venereal warts.

Radical sternectomy and primary musculocutaneous flap reconstruction to control sternal osteitis

OBJECTIVE

Sternal osteitis after median sternotomy is associated with considerable morbidity and mortality. The use of muscle and omentum flaps has been proved as valid adjunct to combat these severe infections. In this study we present our experience with a more radical approach.

METHODS

Sternectomy consisted of the resection of the entire sternum, including the costochondral arches and the sternoclavicular joints, and was followed by the repair of the defect with musculocutaneous flaps without any restabilization of the thoracic wall. Thirteen patients received a vertical rectus abdominis musculocutaneous flap, 14 patients received a pedicled latissimus dorsi musculocutaneous flap, and 12 patients received a free latissimus dorsi musculocutaneous flap (total of 40 flaps in 39 patients of 66 patients who required surgical revision for sternal osteitis of 6078 total patients with sternotomies).

RESULTS

Two patients died within 30 days after the operation (early mortality of 5.1%); however, they did not die of sternal infection, which was cured without any recurrence in all cases. Seventeen patients (44%) required secondary, mostly minor operations for local complications. Despite some paradoxic chest movements, the patient satisfaction rating was unanimously high at the long-term follow-up (0.4 to 8.5 years, median 2.3 years). The short- and long-term complication rates were similar in the three groups.

CONCLUSION

We conclude that radical sternectomy and immediate musculocutaneous flap repair provided definitive control of sternal infection in even the most severe cases, thus reducing infection-related mortality. The trade-off was a substantial rate of local complications; however, these did not cause any relevant morbidity.

Comparative in vitro study of tissue welding using a 808 nm diode laser and a Ho:YAG laser

In vitro porcine arteries and veins have been welded end-to-end using either a 808 nm diode laser combined with an indocyanine green enhanced albumin solder, or with a continuous-wave (cw) Ho:YAG laser without biological solder. The vascular stumps were approached to each other over a coronary dilatation catheter in order to obtain a precise alignment and good coaptation. Standard histology revealed for both welding techniques lateral tissue damage between 2 and 3 mm caused by laser-induced heat. Good solder attachment to the tissue was observed by the use of a scanning electron microscope. The vessels soldered with the 808 nm diode laser using albumin solder showed considerably higher tensile strength (1 N compared to 0.3 N) than vessels welded exclusively by Ho:YAG laser radiation. In contrast, leaking pressure (350 +/- 200 mmHg) and bursting pressure (457 +/- 200 mmHg) were found to be independent of the welding technique used. This study demonstrates that fast (total welding time about 2-5 min), stable and tight microvascular anastomosis can be achieved with the use of a dye-enhanced albumin laser soldering technique and an ancillary coronary dilatation catheter.

Hibernoma: imaging characteristics of a rare benign soft tissue tumor

Hibernoma is a rare benign soft tissue tumor of brown fat. Awareness of the MR imaging appearances of this lesion may allow for improved preoperative diagnosis or at least inclusion of hibernoma as a possible benign differential diagnosis prior to surgery.

Endothelin receptor blockade improves oxygenation in contralateral TRAM flap tissue in pigs

Partial skin and fat necrosis is the most common complication occurring in TRAM flaps. It is related to disturbances of the microcirculation and oxygenation in the contralateral part of the flap. It may be hypothesised that the development of necrosis is promoted by the vasoconstrictor endothelin, the production of which is enhanced in ischaemic flap tissues. The purpose of this study was to evaluate the effect of tezosentan, a new endothelin receptor blocker, on microcirculation and oxygenation in experimental TRAM flaps. The administration of tezosentan began preoperatively (3 mg/kg body weight) and then continued at a rate of 1.5 mg/kg/h. A TRAM flap with a skin island measuring 16 x 8 cm was raised in the middle of the epigastrium in minipigs. The flap was pedicled on the right superior epigastric vessels. Microcirculatory blood flow was measured with laser Doppler flowmetry and tissue oxygen tension was measured with a Clark-type microprobe. Dominant subcutaneous veins were cannulated in both the ipsilateral and the contralateral parts of the flap. Subdermal tissue oxygen tension in the contralateral part of the flap was significantly reduced 4h after surgery to 5 mmHg (ca. 48 mmHg in normal tissue) in the control group, but to only 12 mmHg in the group that had been administered tezosentan (P< 0.05). Furthermore, tezosentan significantly attenuated venous hypertension (14 mmHg versus 24 mmHg), as well as lactate (4.0 mmol/l versus 5.6 mmol/l) and haemoglobin (10.2 g/dl versus 11.4 g/dl) concentrations in the venous effluent of the contralateral part of the flap, although microcirculatory blood flow remained virtually unchanged. Our findings suggest that tezosentan improves oxygenation and metabolism in the jeopardised contralateral flap tissue, probably as a result of a decrease in venous vascular resistance and fluid extravasation.

A comparative evaluation of intrathoracic latissimus dorsi and serratus anterior muscle transposition

BACKGROUND

Comparison of intrathoracic latissimus dorsi (LD) versus serratus anterior (SA) muscle transposition for treatment of infected spaces, broncho-pleural fistulae, and for prophylactic reinforcement of the mediastinum after extended resections following induction therapy.

PATIENTS AND METHODS

Twenty LD and 17 SA transfers were performed for prophylactic reinforcement (11 LD; nine SA), and treatment of infections (nine LD; eight SA) from 1995 to 1998.

RESULTS

The 30-day mortality was 0% following prophylactic reinforcement and 29% following treatment of infections (three LD; two SA). Prophylactic mediastinal reinforcement was successful in 11 of 11 patients with LD and nine of nine with SA transpositions, and treatment of infected spaces in eight of nine patients with LD and two of three with SA transfers. Morbidity requiring re-intervention consisted of flap necrosis (one LD), bleeding (one SA), and skin necrosis over a winged scapula (one SA). Subcutaneous seromas and chest wall complaints were more frequent following LD (45 and 36%, respectively) compared with SA transfers (29 and 27%, respectively), whereas impaired shoulder girdle function was more frequent after SA than after LD transfer (27 vs. 21%).

CONCLUSION

Intrathoracic LD and SA muscle transpositions are both efficient for the prevention or control of infections following complex thoracic surgery, and are both associated with similar and acceptable morbidity and long-term sequelae.

Dynamic study of the distribution of microcirculatory blood flow in multiple splanchnic organs in septic shock

OBJECTIVES

To study dynamic distribution of microcirculatory blood flow in multiple splanchnic organs during septic shock; to test the hypothesis that changes in microcirculatory blood flow in splanchnic organs correlate with changes in regional flow during septic shock.

DESIGN

A prospective, controlled, animal study.

SETTING

Animal laboratory in a university medical center.

SUBJECTS

Nine anesthetized and mechanically ventilated domestic pigs.

INTERVENTIONS

Systemic flow (cardiac output) was measured with thermodilution and regional (superior mesenteric artery) flow with transit time flowmetry. Local blood flow (microcirculatory flow) was continuously measured in splanchnic organs (gastric, jejunal, and colon mucosa, liver, and pancreas) and the kidney with multichannel laser Doppler flowmetry. Septic shock was induced with fecal peritonitis. After 240 mins of sepsis, intravenous fluids were administered to alter hypodynamic shock to hyperdynamic septic shock.

MEASUREMENTS AND MAIN RESULTS

In this severe septic shock model, systemic and regional flows decreased by approximately 50% during the first 240 mins. Similar reductions were recorded in microcirculatory flow in the mucosa of the stomach (-41%; p < .001) and colon (-47%; p < .001). In the jejunal mucosa, on the other hand, flow remained virtually unchanged. Microcirculatory flow was also significantly decreased in the liver (-49%; p < .001), pancreas (-56%; p < .001), and kidney (-44%; p < .001). Administration of intravenous fluids at 240 mins was followed by three-fold increases in systemic and regional flows (approximately 70% above baseline). In the jejunal mucosa, flow also increased significantly above baseline (42%; p < .001), whereas in the stomach and the colon, it barely reached baseline. Kidney blood flow increased to baseline, whereas pancreas and liver flows remained 26% (p < .05) and 34% (p < .001), respectively, below baseline.

CONCLUSION

Changes in microcirculatory blood flow in the splanchnic organs are heterogeneous, both in early hypodynamic and in hyperdynamic septic shock, and cannot be predicted from changes in systemic or regional flows. Microcirculatory blood flow in the jejunal mucosa remains constant during early septic shock, whereas pancreatic blood flow decreases significantly more than regional flow.

The effect of pedicle artery vasospasm on microhemodynamics in anatomically perfused and extended skin flap tissue

The aim of this study was to evaluate quantitatively the influence of pedicle artery vasospasm on the microcirculation in skin flaps, particularly in the jeopardized extended portions. For this purpose, the hamster island skin flap model was used, which allowed for simultaneous assessment of hemodynamics in both the pedicle artery and the microvasculature of the flap by intravital microscopy. Vasospasm was induced by applying a V3 microvascular clamp for 30 seconds. Clamping resulted in a severe vasospasm, with the artery exhibiting a diameter of 7% +/- 2% (mean +/- standard error) of its original diameter (n = 10; p < 0.01), and with a reduction of total blood flow to the flap of 11% +/- 2% (p < 0.01). Diameter and blood flow recovered gradually to baseline levels after 25 and 15 minutes respectively. During recovery from severe pedicle artery vasospasm (moderate to mild vasospasm), the arterioles in the anatomically perfused flap tissue (n = 38) showed reactive vasodilation (p < 0.01), which was absent in the extended tissue (n = 49; p < 0.01 vs. anatomic). At a pedicle artery vasospasm of 50% of the original diameter, blood flow was restored to normal levels in the anatomically perfused arterioles, but remained below baseline in the extended part (partly p < 0.05 vs. baseline and anatomic). The findings suggest that the development of ischemic necrosis in extended flap portions may be promoted by prolonged, moderate vasospasm, which is well tolerated in the anatomically perfused tissue because of its high capacity for implementing compensatory local regulatory mechanisms.

Continuous measurements of microcirculatory blood flow in gastrointestinal organs during acute haemorrhage

Hypoperfusion of splanchnic organs is an important contributor to the development of multiple organ failure after major surgery and trauma. During general anaesthesia and surgery we compared changes in systemic haemodynamics and regional blood flow with changes in the distribution of microcirculatory flow (MBF) in multiple splanchnic organs in pigs exposed to acute haemorrhage. Seven pigs (25 kg) were bled to a mean arterial pressure of 40 mm Hg; 180 min later the shed blood was retransfused. MBF was measured in the intestinal mucosa (stomach, jejunum, colon), pancreas, liver and kidney using a six-channel laser Doppler flowmeter. Cardiac output was measured by thermodilution and superior mesenteric artery flow by ultrasonic flowmetry. During haemorrhage, MBF in the gastric and colon mucosa and flow in the liver and kidney decreased to a similar extent to regional and systemic flows (30-50%). In contrast, MBF in the jejunal mucosa remained virtually unchanged and flow in the pancreas decreased significantly more than systemic and regional flows (60%, P < 0.05). We conclude that: (1) changes in the distribution of MBF in the gastrointestinal tract during acute haemorrhage are heterogeneous and cannot be predicted from changes in systemic or regional haemodynamics; (2) MBF in the jejunal mucosa did not decrease during haemorrhage, indicating that autoregulation of blood flow in the mucosa remained intact during shock; and (3) MBF in the pancreas decreased significantly more than systemic and regional flows during shock, suggesting that the pancreas is particularly vulnerable to haemorrhage.

Functional assessment of chest wall integrity after methylmethacrylate reconstruction

BACKGROUND

All patients with extensive resection of the anterolateral chest wall and the sternum followed by reconstruction with methylmethacrylate substitutes were assessed prospectively 6 months after the operation to delineate chest wall integrity with pulmonary function and cine-magnetic resonance imaging.

METHODS

Twenty-six patients underwent chest wall reconstruction by use of methylmethacrylate between 1994 and 1998 due to primary tumors in 35%, metastases in 27%, T3 lung cancer in 19%, and debridement for radionecrosis and osteomyelitis in 19% of patients. Three to eight ribs were resected and additional sternum resection was performed in 39% of patients.

RESULTS

There was no 30-day mortality. All patients were extubated after the operation without need for reintubation. Prosthesis dislocation occurred in 1 patient and infection in 2 patients during follow-up. Nineteen patients (73%) suffered no restrictions of daily activities. Clinical examination revealed normal shoulder girdle function in 77% of patients. There was no significant difference between preoperative and postoperative FEV1 (forced expiratory volume in 1 second) measurements in patients with lobectomy or wedge resections. Cinemagnetic resonance imaging revealed concordant chest wall movements during respiration in 92% of patients without paradoxical movements or implant dislocations being observed.

CONCLUSIONS

Large defects of the anterolateral chest wall and sternum can be reconstructed efficiently with methylmethacrylate substitutes with minimal morbidity and excellent cosmetic and functional outcome.

Quantitative assessment of microhemodynamics in ischemic skin flap tissue by intravital microscopy

Skin flaps are susceptible to ischemia, which may result in tissue necrosis particularly in areas deprived of their original anatomic blood supply. The pathophysiology of skin flap failure has been debated for many years, but due to methodological insufficiencies, every proposed theory has remained hypothetical. The aim of this study was to gain more evidence for the mechanisms involved in flap ischemia by assessing quantitatively hemodynamic parameters such as diameter, flow velocity, and volume flow in the microcirculation of a flap. To this end the authors developed a new island flap on the back of Syrian golden hamsters that allowed intravital microscopic investigation. The flap included an extended portion, which was deprived of its original anatomic blood supply. One hour after flap dissection, blood flow was 42% to 66% lower in all microvessels in the extended area than in the anatomically perfused part of the flap (p<0.05). In the entire microvasculature, a significant gradual decline of blood flow was observed over time. Any blood flow reduction was caused to a major extent by diminished flow velocity. At all times, microvascular diameters were slightly larger in the extended portion of the flap than in the anatomically perfused portion of the flap. The authors conclude that their new model is a unique tool for investigating microhemodynamic mechanisms involved in flap ischemia. This study reveals hypoperfusion of extended flap tissue, which is attributed to diminished arterial perfusion pressure but not to vasoconstriction or arteriovenous shunting.

Haemodynamics and oxygen tension in the microcirculation of ischaemic skin flaps after neural blockade and haemodilution

The aim of this study was to evaluate the effects of neural blockade and extended normovolaemic haemodilution on haemodynamics and oxygenation in the microcirculation of ischaemic skin flaps using a recently developed island flap on the back of Syrian golden hamsters. One part of the flap was made ischaemic by inducing a random perfusion pattern following interruption of the axial blood supply. The model permitted quantitative assessment of the microhaemodynamics and oxygen tension in all microvascular segments by the use of intravital microscopy. Oxygen tension was measured with the phosphorescence decay method. Neural blockade was induced by applying 2% lidocaine to the neurovascular flap pedicle. Haemodilution was achieved by isovolaemic exchange of 50% of the total blood volume with dextran 70. One hour after surgery (baseline), centreline velocity was significantly reduced to 20-44% in all the microvessels in the randomly as compared to the axially perfused part, whereas the diameters were slightly larger (ns). In the control group, blood flow declined by 20-75% (P< 0.01 vs. baseline) over time in the entire flap. Flow reduction was significantly attenuated by haemodilution in the entire flap, but more pronounced in the ischaemic part. Neural blockade caused marked vasodilatation and significantly improved blood flow in the axially but not in randomly perfused microvessels. After 8 h, oxygen tension ranged from 4.0 to 6.1 mmHg in the axial part (means, ns between groups), whereas in the ischaemic part, it was 0.8-1.0 mmHg (P< vs. axial) in the control and neural blockade groups, and 1.7 mmHg (ns vs. axial and between groups) after haemodilution. Our findings indicate that neural blockade does not improve microcirculation and oxygenation in randomly perfused flap tissue because the sympathetic regulation of its microcirculation is overruled by autoregulatory mechanisms. Normovolaemic haemodilution, even after a 50% exchange, augments oxygenation in ischaemic flap tissue due to increased blood flow particularly in the randomly perfused tissue.

Effects of epidural anaesthesia on microcirculatory blood flow in free flaps in patients under general anaesthesia

It has been suggested that epidural anaesthesia may increase blood flow in free flaps on the lower extremity. The objective of the present study was to test this hypothesis in 21 patients undergoing reconstructive surgery of the lower extremity with free muscle (n = 8), fasciocutaneous (n = 6) or musculocutaneous (n = 7) flaps. Microcirculatory blood flow was measured continuously with a multichannel laser Doppler flowmetry, both in muscle and skin of the free flap as well as in the intact skin and muscle on the same extremity. After completion of surgery, general anaesthesia was continued and the epidural block was induced by an injection of 2% lignocaine-hydrochloride into a pre-operatively inserted and tested epidural catheter. The epidural block caused no change in microcirculatory flow in the intact skin and muscle, however, it resulted in a marked decrease in microcirculatory blood flow in all the free flaps studied (20-30%; P < 0.05). The epidural block also caused a significant decrease in mean arterial blood pressure, from 85 (+/- 2.8) mmHg to 68 (+/- 2.8) mmHg (P < 0.01). It was concluded that epidural anaesthesia may decrease microcirculatory blood flow in free flaps on the lower extremity by diverting flow away from the flap to normal intact tissues (a steal phenomenon).

Regular slow wave flowmotion in skeletal muscle is not determined by nitric oxide and endothelin

In a previous study we showed that the generation of regular slow wave flowmotion (rSWFM, 1-3 cycles per minute) in skeletal muscle of anesthetized rats was related to local changes of arterial pressure and microcirculatory blood flow (MBF), which suggests an involvement of pressure- or flow-induced mechanisms. The present experiments were designed to test the role of flow-dependent endothelial autacoids, such as nitric oxide (NO) and endothelin, in the generation of SWFM. The effects of NO-donor sodium nitroprusside (SNP), the partly NO-dependent metabolite adenosine (ADO), the NO-synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), and the mixed endothelin receptor blocker bosentan (BOS) were analyzed. MBF and rSWFM were assessed by laser Doppler flowmetry. rSWFM appeared in 7 out of 14 preparations after ADO (200 microg/kg/min), but not after SNP (100 microg/kg/min), L-NAME (30 mg/kg iv), and BOS (10 mg/kg iv). Its occurrence was associated with a significant decrease in arterial pressure to 50 +/- 3% (mean +/- SEM) of the baseline, provided that MBF was not enhanced. When given after induction of rSWFM by a 25% hemorrhage, SNP (50 microg/kg/min) totally abolished rSWFM and ADO (100 microg/kg/min) reduced rSWFM frequency from 2.17 +/- 0.08 to 1.72 +/- 0.08 cycles per minute (cpm) (P < 0.05), whereas the frequency was not affected by the other drugs. ADO, l-NAME (30 mg/kg iv), and BOS (10 mg/kg iv) lead to changes in rSWFM amplitude which showed a drug-independent negative correlation to changes in both MAP and MBF (R(2) = 0.61, multiple regression) in the ranges of 57-176% of MAP before drug application, and 72-120% of MBF, respectively. We conclude that NO and endothelin are not involved in the generation of rSWFM. Our findings strongly suggest that the activity of rSWFM depends on a reduction of vascular wall tension and is inhibited by SNP.

[Surgical treatment of malignant melanoma]

Early diagnosis and total tumor excision are fundamental to assure a favorable outcome in the treatment of the malignant melanoma. Previously a large local excision up to 5 cm was recommended. In the past two decades some prospective studies showed the same survival rate when using narrower margins of excision (1-3 cm). The elective lymphadenectomy increases the survival rate only in a small group of patients and has a high rate of complications. The concept of lymphatic mapping can greatly help in finding the lymph node ("sentinel lymph node") which is the first one to receive lymphatic drainage from the affected area. This node has the highest probability of containing a metastasis and is excised. With this procedure the number of patients requiring lymphadenectomy can be limited to those who have documented lymph node metastases. The sentinel biopsy technique can provide new insight into the tumor biology of melanoma and helps in determining adjuvant therapy. In order to evaluate the influence of sentinel node biopsy on survival rate of melanoma patients clinical trials have been designed. Systemic melanoma metastases carry a poor prognosis. Surgical resection of isolated metastases may provide good palliation, in combination with other therapies.

Comparative objective and subjective analysis of temporalis tendon and microneurovascular transfer for facial reanimation

The aim of this study was to compare objectively and subjectively the results after temporalis tendon and microneurovascular transfer for reanimation of the paralysed face. For the objective analysis, measurements of the distances between static and dynamic points in three-dimensional space were performed at rest and during smiling. The patients were assessed subjectively by non-professionals scoring videotapes. The range of motion of the oral commissure on smiling was 1.7 mm (0.8, mean and SE) after tendon and 5.5 mm (1.6) after microneurovascular transfer (P < 0.05) without showing teeth, and 0.6 mm (1.3) vs 3.6 mm (2.4, ns) with showing teeth. Compared with the healthy side, the excursions reached 6% (16) after tendon and 71% (26, P < 0.05) after microneurovascular transfer for smiling without, and -4% (14) vs 19% (14, ns) for smiling with showing teeth, respectively. Virtually no difference was found in the measurements at rest as well as in the subjective evaluation. Swelling of the cheek (28%) and tethering of the skin (24%) were shown to be the most disturbing symptoms after microneurovascular transfer. Better excursion and symmetry of the oral commissure were achieved by microneurovascular reconstruction for voluntary smile. However, the aesthetic outcome after microneurovascular transfer is markedly impaired by chronic complications including swelling of the cheek and tethering of the skin, which were not detected by the three-dimensional measurement technique used. We conclude that the aesthetic appearance should be considered equally important as the range of motion in the reanimated face.

[Body contouring by removal of skin and fatty tissue]

There is an increasing demand for surgical correction of the body contour in the modern society. We present a summary of the indications and techniques of the most important interventions on the abdomen, hip, thigh and arm. The operations aim at the correction of localized excesses of fat and skin tissue with liposuction and dermolipectomy. Liposuction is performed through small skin incisions, which results in minimal scar formation; and which is associated with minimal complication rates. The indication for liposuction is restricted to the conditions in which the overlying skin is capable to retract and adapt itself to the new contour. Otherwise, or if an excess of skin is the cause of the deformity, a dermolipectomy is required. In this case, the incisions are chosen in a way that the resulting scar may be hidden as well as possible.

Effects of sodium nitroprusside and phenylephrine on blood flow in free musculocutaneous flaps during general anesthesia

BACKGROUND

Hypoperfusion and necrosis in free flaps used to correct tissue defects remain important clinical problems. The authors studied the effects of two vasoactive drugs, sodium nitroprusside and phenylephrine, which are used frequently in anesthetic practice, on total blood flow and microcirculatory flow in free musculocutaneous flaps during general anesthesia.

METHODS

In a porcine model (n = 9) in which clinical conditions for anesthesia and microvascular surgery were simulated, latissimus dorsi free flaps were transferred to the lower extremity. Total blood flow in the flaps was measured using ultrasound flowmetry and microcirculatory flow was measured using laser Doppler flowmetry. The effects of sodium nitroprusside and phenylephrine were studied during local infusion through the feeding artery of the flap and during systemic administration.

RESULTS

Systemic sodium nitroprusside caused a 30% decrease in mean arterial pressure, but cardiac output did not change. The total flow in the flap decreased by 40% (P < 0.01), and microcirculatory flow decreased by 23% in the skin (P < 0.01) and by 30% in the muscle (P < 0.01) of the flap. Sodium nitroprusside infused locally into the flap artery increased the total flap flow by 20% (P < 0.01). Systemic phenylephrine caused a 30% increase in mean arterial pressure, whereas heart rate, cardiac output, and flap blood flow did not change. Local phenylephrine caused a 30% decrease (P < 0.01) in the total flap flow.

CONCLUSIONS

Systemic phenylephrine in a dose increasing the systemic vascular resistance and arterial pressure by 30% appears to have no adverse effects on blood flow in free musculocutaneous flaps. Sodium nitroprusside, however, in a dose causing a 30% decrease in systemic vascular resistance and arterial pressure, causes a severe reduction in free flap blood flow despite maintaining cardiac output.

Dissociation between volume blood flow and laser-Doppler signal from rat muscle during changes in vascular tone

Although the laser-Doppler flowmetry (LDF) signal from skeletal muscle has been shown to provide a good measure of blood flow under some conditions, its behavior during administration of vasoactive substances has never been addressed. The aims of this study were to compare 1) changes in LDF signal with those in total muscle blood flow measured with radioactive microspheres after ganglionic blockade (chlorisondamine) and during administration of angiotensin II (ANG II), phenylephrine (PE), and isoproterenol (Iso) and 2) changes in vascular resistance estimated by the two techniques. The LDF signal from the biceps femoris muscle was investigated in anesthetized male Wistar rats. Ganglionic blockade led to a significant (P < 0.05) fall in mean arterial pressure (MAP) [medians (lower, upper quartiles): 78 (72, 83) vs. 127 (114, 138) mmHg under basal conditions], muscle blood flow (MBF, microsphere technique; 61%), and the LDF signal (29%). Muscle vascular resistance (MVR = MAP/MBF) was increased (64%, P < 0.05), but vascular resistance estimated as MAP/LDF signal (MVRLDF) was unchanged. During ANG II and PE infusions, MAP rose (P < 0.05) to 178 (155, 194) and 127 (124, 142) mmHg, respectively; MBF did not change compared with the preinfusion (postganglionic blockade) level and remained significantly (P < 0.05) lower than baseline, whereas the LDF signal increased up to a level not different from baseline. MVR rose and was significantly (P < 0.05) higher than baseline, whereas MVRLDF did not differ significantly from baseline. During Iso infusion, MAP fell [58 (56, 60) vs. 94 (92, 102) mmHg, P < 0.05], the LDF signal was reduced (49%, P < 0.05) despite a large increase in MBF (139%, P < 0.05), and MVR fell (74%, P < 0.05), whereas MVRLDF did not change vs. preinfusion level. Our results suggest that 1) changes in the LDF signal from muscle may not correlate with changes in total muscle blood flow measured by the microsphere technique during infusion of vasoactive substances and 2) the use of LDF data for estimation of MVR during changes in vascular tone in rat skeletal muscle is probably not appropriate.

Effects of extradural anesthesia on microcirculatory blood flow in free latissimus dorsi musculocutaneous flaps in pigs

Free musculocutaneous flaps are used frequently in plastic surgery to reconstruct soft-tissue defects after radical cancer surgery and trauma. Despite improved surgical techniques, some of these flaps fail due to insufficient blood supply. Extradural anesthesia causes both sensory (pain relief) and sympathetic (vasodilatation) block that may be advantageous in free-flap surgery. This hypothesis, however, has not yet been studied. An experimental model in pigs was developed in which clinical conditions for anesthesia and microvascular surgery on the lower extremity were simulated as closely as possible. The effects of extradural anesthesia as well as phenylephrine infusion, combined with general anesthesia, on central hemodynamics and on microcirculatory blood flow in skin and muscle of the latissimus dorsi free flap were studied. After surgery, seven animals received extradural anesthesia during stable normovolemic conditions and another seven during mild hypovolemia (10 percent blood loss). The extradural block was objectively evaluated using the temporal summation test. Thirty minutes after induction of extradural anesthesia, the animals received an intravenous infusion of phenylephrine 1 microgram/kg per minute over a period of 15 minutes. Multichannel laser-Doppler flowmetry was used to measure microcirculatory blood flow in skin and muscle of the free flap as well as in control skin and muscle on the same extremity simultaneously. In normovolemic animals, extradural block caused a 10 percent decrease in mean arterial pressure and cardiac output and an approximately 20 percent decrease in microcirculatory blood flow in both the skin and muscle of the flap (all changes were nonsignificant). In slightly hypovolemic animals, however, extradural anesthesia caused a significant decrease in cardiac output (31 percent, p < 0.01), mean arterial pressure (24 percent, p < 0.01), and in mean blood flow in the flap muscle (22 percent, p < 0.05) and skin (20 percent, p < 0.05). During phenylephrine infusion, mean arterial pressure increased significantly (p < 0.05) in both hypovolemic and normovolemic animals, while cardiac output and microcirculatory blood flow in the flap remained almost unchanged. Extradural anesthesia does not improve microcirculatory blood flow in free musculocutaneous flaps in pigs. It causes a significant decrease in cardiac output, mean arterial pressure, and microcirculatory blood flow in slightly hypovolemic animals. During phenylephrine infusion, the microcirculatory blood flow in free flaps slightly improves due to the increase in mean arterial pressure. We suggest that extradural anesthesia for microvascular surgery should be used with great caution until human data are available.

Relationship between arterial pressure and blood flow in the generation of slow-wave flowmotion in rat skeletal muscle

The objective of this study was to determine the role of hypotension and hypoperfusion in the induction of regular slow-wave flowmotion (SWFM) in skeletal muscle in vivo. SWFM and microcirculatory muscle blood flow (MBF) were assessed by laser Doppler flowmetry in anesthetized rats exposed to: (1) graded hemorrhage (n = 15); (2) partial occlusion of the feeding artery (n = 6); (3) partial occlusion of the vein (n = 6), and (4) the vasodilator hydralazine (n = 10). Mean arterial pressure (MAP) was significantly reduced to 65 +/- 2.1% after hemorrhage and hydralazine before (64 +/- 2.4%) and after (42 +/- 1.8%) additional blood loss, but remained unchanged after venous occlusion. The pressure of the feeding artery fell to 38 +/- 1.2% after partial occlusion. MBF dropped significantly to 74 +/- 4.2% after hemorrhage, 54 +/- 5.6% after arterial and 53 +/- 3.0% after venous occlusion. Hydralazine caused MBF to rise to 192 +/- 21.8% before additional blood withdrawal and returned to normal values after it. SWFM was observed in all animals after hemorrhage and arterial occlusion, but in none after venous occlusion. In the hydralazine group, SWFM occurred only after blood loss. The hemoglobin concentration was reduced to 82 +/- 2.1% after hemorrhage. It remained normal after hydralazine administration, but decreased to 79 +/- 1.2% after the subsequent blood withdrawal. We conclude that arterial hypotension, but not hypoperfusion, induces SWFM, and hyperperfusion prevents it. Our results support the hypothesis that SWFM is generated by a reduction of vascular wall tension.

Descending necrotizing mediastinitis: surgical treatment via clamshell approach

BACKGROUND

Descending necrotizing mediastinitis requires an early and aggressive surgical approach to reduce the high morbidity and mortality associated with this disease. The clamshell incision has provided excellent exposure of the entire mediastinum and both pleural cavities and was assessed in patients suffering from descending necrotizing mediastinitis.

METHODS

Three patients with descending necrotizing mediastinitis and bilateral pleural empyema due to invasive streptococcal infections were operated on with this method. Radical debridement of the mediastinum and bilateral decortication was performed through a clamshell incision, including pericardiectomy in 2 patients. All patients received initially a high dose of antibiotic regimen, 2 had bilateral chest tube drainage, and 1 had mediastinal drainage and pleural debridement via cervical mediastinotomy and thoracoscopy, respectively. All these measures alone, however, failed to control the disease.

RESULTS

The clamshell incision offered an excellent exposure for bilateral decortication and debridement of the entire mediastinum including pericardiectomy. One patient, who was referred in critically ill condition, died of multiorgan failure in the postoperative period. The remaining 2 patients recovered without further interventions and without evidence of phrenic nerve palsy, sternum osteomyelitis, or sternal override.

CONCLUSIONS

The clamshell approach offers an excellent exposure for a complete one-stage surgical treatment with mediastinal debridement and bilateral decortication in patients suffering from descending necrotizing mediastinitis in the absence of profound septic shock.

A dynamic study of the circulation in the gracilis muscle in humans

The aim of the present study was an evaluation of the relative importance of the proximal and distal pedicles for the perfusion of the gracilis muscle flap, as well as to evaluate the importance of the functional connections between the proximal and distal vascular territories. Ten gracilis muscles were investigated in nine patients. They were all operated on in the supine position under general anesthesia. Microcirculatory blood flow (MBF) in the muscle was measured by a dual-channel laser Doppler flowmeter. Two angled probes were sutured opposite to the entry of the proximal and distal pedicles into the muscle, and were kept in place throughout the measurements. Data were acquired on line via a multichannel interface with acquisition/analysis software to a portable computer. The following measurements were done: during baseline with both pedicles intact; during occlusion of the proximal pedicle; after clamp release; during occlusion of the distal pedicle; after clamp release; after motor-nerve transection; and after disinsertion of the muscle from bone attachments. After clamping the proximal pedicle, MBF decreased proximally to 57 +/- 5 percent (p < 0.01), but remained unchanged distally. After occlusion of the distal pedicle, MBF remained virtually unchanged proximally (92 +/- 4 percent, NS), but decreased to 72 +/- 6 percent (p < 0.05) distally. There was a significantly greater decrease in MBF when the proximal pedicle was clamped, than after clamping the distal pedicle (p < 0.01). There was a strong linear correlation (r = 0.85) between the proximal and distal MBF after occlusion of the corresponding pedicle. Transection of the motor nerve resulted in a moderate increase in MBF values proximally (130 +/- 10 percent, p < 0.05), but not distally (108 +/- 18 percent, NS). Detachment of the muscle led to a distinct increase of MBF in both vascular territories (proximally 175 +/- 28, percent p < 0.05; distally 157 +/- 20 percent, p < 0.05). These measurements demonstrated the dominant role of the proximal pedicle in the gracilis muscle in humans. Furthermore, it was shown that each of the two pedicles (proximal and distal) has its own vascular territory, and that both territories are partially connected by intramuscular vascular anastomoses. The predictable extent of blood flow varies in individual cases and should be measured intraoperatively. In cases of marginal perfusion to the distal part of the muscle, a delay procedure should be considered.

Free latissimus dorsi flap for chest wall repair after complete resection of infected sternum

BACKGROUND

Radical debridement, followed by muscle flap cover, has significantly reduced morbidity and mortality of infected sternotomy wounds. The pectoralis major, rectus abdominis, and greater omentum flaps are most commonly used, whereas the latissimus dorsi muscle is rarely employed.

METHODS

In 7 patients with persistent infection and necrosis of the sternum, radical and extensive debridement including the sternum, costochondral arches, manubrium and sternoclavicular joints was performed. A free latissimus dorsi flap was used for soft tissue reconstruction without additional stabilization of the chest wall.

RESULTS

All flaps survived without revision of the anastomosis. In the follow-up period (22 months to 5 years) no recurrent infection was observed. Three patients died during the study period (3 to 24 months after operation) due to causes not related to sternum operation. No additional weakness, pain, or restricted movements of the shoulders due to missing sternum was observed.

CONCLUSIONS

Our findings suggest that the use of free latissimus dorsi flap after complete sternectomy for infection has several advantages: it provides abundant tissue to allow radical and extensive debridement, obliterates completely the dead space, and helps to control infection. Even without additional chest wall reconstruction it gives enough stability to allow pain-free normal daily activities.

Haemorrhage during anaesthesia and surgery: continuous measurement of microcirculatory blood flow in the kidney, liver, skin and skeletal muscle

Multichannel laser Doppler flowmeters allow continuous, simultaneous measurement of perfusion in several organs. We measured microcirculatory blood flow in the kidney, liver, skin and skeletal muscle in 10 anaesthetized rats subjected to abdominal surgery and graded haemorrhage (withdrawal of 5% total blood volume every 10 min). Mean arterial blood pressure, heart rate and haemoglobin concentrations were also measured. Muscle blood flow decreased after only 10% blood loss, but without significant changes in the other organs. At this time the perfusion signal from the muscle was cycling 2-3 times per min (slow wave flowmotion) which was never seen in any other organ. After 35% blood loss, all organs monitored maintained approximately 70% of initial flow, despite a 45% decrease in mean arterial pressure from 104 +/- 12 to 55 +/- 9 mmHg (mean +/- SD). After 40% blood loss there was a sharp decrease in blood flow in all organs. Haemoglobin concentration decreased from 14.4 +/- 0.8 to 10.8 +/- 1.3 mg dL-1 after 45% blood loss. We conclude that laser Doppler flowmetry is useful for continuous measurement of microcirculatory blood flow in several organs simultaneously during haemorrhagic hypovolaemia. It showed that microcirculatory blood flow in skeletal muscle is particularly sensitive to lesser degrees of blood loss during anaesthesia. Hypovolaemia-induced slow wave flowmotion occurred only in skeletal muscle, which may be linked to fluid mobilization during haemorrhage.

Late results of breast reconstruction with free TRAM flaps: a prospective multicentric study

When the free TRAM flap was introduced for breast reconstruction, it was supposed to have many advantages over the pedicled TRAM flap: good perfusion of all four zones, better mobility and easier shaping of the breast, lower incidence of abdominal-wall complications, and less restrictive selection of patients. However, we have experienced several complications after free TRAM flaps in our practice, including fat necrosis, partial and complete flap necrosis, abdominal-wall weakness, and hernias. In order to evaluate the incidence and types of complications, as well as the influence of preoperative risk factors (chemotherapy, radiotherapy, overweight, smoking habits, and abdominal scars), on complications, a multicentric prospective study including Bern (Switzerland), Leuven (Belgium), Stuttgart (Germany), and Verona (Italy) was designed. In 111 consecutive patients, operated on over a period of 18 months, 123 flaps were done; 99 flaps were unilateral and 24 bilateral, and 36 were used for primary and 87 for late reconstruction. There was no preoperative selection of patients. The follow-up period was from 8 to 24 months (average 19 months). A two-team operating approach was used. All four zones were always included in the flap, and the end-to-end anastomoses were done to the thoracodorsal, the circumflex scapular, or the internal mammary arteries. The total number of fat and flap necroses was 24 (19.5 percent), 6 (5 percent) minor and 4 (3 percent) major fat necroses, 2 (1.6 percent) minor and 6 (5 percent) major flap necroses, and 6 (5 percent) total flap necroses. Twenty-two (20 percent) patients had abdominal-wall complications. The results of this study show that the complication rate of free TRAM flaps is considerable. Preoperative risk factors did not play a major role in the development of complications and should not be considered as contraindications for free TRAM flap surgery. All total flap failures resulted from impaired arterial inflow to the flap, and the choice of recipient vessel did not influence the outcome. The incidence of total flap failures might be reduced by good postoperative flap monitoring and early revision of the anastomosis. Partial fat and flap necroses might be prevented by removing the fat under the scarpa fascia in zones 4 and 3 or by reducing zone 4. Sparingly harvesting the rectus muscle and its sheath as well as the use of mesh in the rectus sheath repair may reduce the abdominal-wall complications.

Continuous perioperative monitoring of microcirculatory blood flow in pectoralis musculocutaneous flaps

Hypovolemia and hypotension in traumatized patients as well as those undergoing long-lasting surgical procedures lead to hypoperfusion of tissues. Combined with the trauma of flap elevation and the warm ischemia during performance of the anastomoses, hypoperfusion of flap tissues may lead to flap failure. The influence of hypovolemia, ischemia and reperfusion on flap macro- and microcirculation was studied in an acute experiment on a new musculocutaneous pectoralis flap developed in minipigs. Using a multichannel laser Doppler system we studied, simultaneously and continuously, microcirculatory flow (MBF) in both the skin and muscle of the flap as well as in the contralateral control skin and muscle in anesthetized minipigs (n = 7). Measurements were done before and after raising the flap, after 90 min of flap ischemia, during mild to moderate hypovolemia (5%, 10%, 15%, and 20% blood loss) and during and after restoration of blood volume. Electromagnetic flowmetry was used to measure total blood flow (TBF) to the flap. All animals remained hemodynamically stable during the experiment. The flap MBF decreased by 20% in the skin and 25% in the muscle after flap elevation with no changes in the control skin and muscle. After flap ischemia and reperfusion, MBF returned to post-elevation values while TBF showed a significant increase as compared to MBF (P < 0.05). Hypovolemia caused a gradual drop in cardiac output (25%) and mean arterial pressure (40%), but both recovered above the baseline after reinfusion of shed blood. Hypovolemia also caused a 60% reduction in MBF in both flap skin and muscle, and only 20-23% in control skin and muscle (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of halothane and isoflurane anaesthesia on microcirculatory blood flow in musculocutaneous flaps

Hypoperfusion and necrosis in musculocutaneous flaps used for reconstruction of tissue defects is still a significant clinical problem. Although the causes of hypoperfusion are frequently surgical in nature, little is known about the effects of anaesthetic management on blood flow in flaps or the outcome of flap surgery. We compared in minipigs the effects of halothane and isoflurane anaesthesia in equipotent doses on microcirculatory blood flow (MBF) in the skin and muscle part of musculocutaneous flaps and also in intact (control) skin and muscle. Measurements were made during stable normovolaemic conditions and during mild to moderate hypovolaemia (withdrawal of 5%, 10% and 15% of total blood volume). Multi-channel laser Doppler flowmetry (LDF) was used to measure MBF and electromagnetic flowmetry (EMF) for total flap blood flow. During normovolaemic conditions there was no significant difference between the two groups in central haemodynamic or respiratory data. After 15% blood loss, however, there was a significant decrease in mean arterial pressure and cardiac output in the halothane group while there was no significant change in the isoflurane group (P < 0.05). MBF in control skin, control muscle and flap muscle remained approximately 10-15% higher in the isoflurane than in the halothane group throughout the study. In the isoflurane group, MBF in flap skin was unchanged during normovolaemia and there was less than 10% decrease during hypovolaemia. In the halothane group hypovolaemia caused a significant decrease in MBF in flap skin: 27% decrease after 5% blood loss, 45% decrease after 10% blood loss and 49% decrease after 15% blood loss compared with 5%, 20% and 21%, respectively, in intact skin.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of age on the cardiovascular response during graded haemorrhage in anaesthetized rats

The present study was designed to follow the cardiovascular response to graded haemorrhage in two groups of adult rats of different ages. Group A (n = 10) had a mean body weight (bwt) of 655 g (50 weeks old) and group B (n = 10) had a mean bwt of 250 g (12 weeks old). After induction of anaesthesia, the carotid artery was cannulated for continuous intra-arterial blood pressure monitoring and for controlled haemorrhage. Five per cent of the total blood volume (TBV) was removed every 15 min until a maximum of 50% was reached. Mean arterial pressure (MAP) fell by 4-9 mm Hg each time 5% TBV was removed in both groups, and at the end of the study the MAP was comparable in the two groups (34 +/- 10 mm Hg in group A and 28 +/- 8 mm Hg in group B). There were no significant changes in heart rate (HR) in the young animals during haemorrhage, while there was a significant drop in heart rate in the older animals when blood loss exceeded 15% of TBV (P < 0.05). A significant difference was also observed in HR between the two groups of animals with blood loss in excess of 20% TBV (P < 0.05). It was concluded that although the hypotension induced by graded haemorrhage was similar in young and old rats, the older animals were less able to maintain their HR, probably as a consequence of age- and anaesthetic-related changes in sympathetic activity.

Double vascularized fibulas for reconstruction of large tibial defects

Vascularized fibular grafts have proven to have many advantages over nonvascularized transplants for treatment of large segmental bone defects in the extremities. Fibulas are typically impacted into the medullary canal and fixed with wires or screws. Consolidation has often been delayed and full weightbearing was only possible after graft hypertrophy, usually 12 to 18 months after reconstruction. In order to shorten the time of consolidation and to achieve early full weightbearing, the authors propose a sound biomechanical reconstructive concept: a) stable but not devascularizing osteosynthesis of the osteotomy to shorten the time of consolidation; b) a double-strut fibular graft that yields enough strength for early weightbearing, without the need for bone hypertrophy; and c) additional cancellous bone grafts, to enhance the long-term stability of the reconstruction. Seven patients with tibial defects ranging between 6 and 17.5 cm were treated according to this concept. In four cases, free vascularized fibula was transferred first. Six weeks later, a vascularized, ipsilateral fibula-pro-tibia procedure was done, and the space between the fibulas was filled with cancellous bone grafts. In three patients, a free, vascularized, double-barrel, fibula transfer was done, since the tibial defect was less than 10 cm. Cancellous bone grafts between the fibulas were added only 6 weeks later. In five cases, the free fibula transfer was combined with a latissimus dorsi myocutaneous flap. In six patients, healing was uneventful. In one patient, hypoperfusion of the lower extremity and the vascularized grafts eventually resulted in a below-knee amputation. In all six successful cases, union resulted within 3 months.(ABSTRACT TRUNCATED AT 250 WORDS)

[Reconstruction of the lower extremity using partially destroyed or amputated parts]

We are often confronted with heavy destructions of the lower extremities, where there is no possibility to conserve the limb, because of the general or/and local conditions. In this situation it's wise to preserve vital rest structures that can be used for primary or secondary reconstructions of the injured limb. There are different possibilities, some of them are presented in the cases described in this article.

Effects of ketoprofen on respiratory and circulatory changes in endotoxic shock

OBJECTIVE

To study the effects of ketoprofen, a dual inhibitor of the arachidonic acid metabolism, on hemodynamic and respiratory changes during endotoxic shock.

DESIGN

Prospective, randomised, controlled study using an established intact animal model of endotoxic shock in sheep.

SETTING

An animal laboratory in a university hospital.

INTERVENTIONS

4 groups were studied (n = 7 in each). Group K received ketoprofen and group A received aspirin 30 min before start of endotoxin infusion. Group E received endotoxin, but no drug treatment. Group C received neither endotoxin nor drug treatment. All the animals were anaesthetised with ketamine, had controlled ventilation with FiO2 = 0.5 and received Ringer's lactate at an infusion rate that would keep the pulmonary capillary wedge pressure constant.

RESULTS

Both ketoprofen and aspirin prevented the early rise in pulmonary arterial pressure that occurred in group E a few minutes after start of i.v. infusion of endotoxin. Furthermore, ketoprofen prevented any significant changes in arterial blood pressure, arterial oxygen tension, oxygen delivery index, oxygen extraction ratio, respiratory compliance, intrapulmonary shunt fraction, and platelet counts that occurred in group E. Aspirin, on the other hand, provided only partial and time limited (1-2 h) protection against these changes. Wet-to-dry weight ratios of the lungs were significantly lower in the ketoprofen treated than in the untreated shock controls and the aspirin treated animals.

CONCLUSION

Ketoprofen completely prevented the changes in hemodynamics and respiratory function observed in control-endotoxin-treated animals.

Doppler duplex for the evaluation of the degree of stenosis in carotid arteries in the rat

This study evaluates the accuracy of the Doppler duplex technique for providing reliable information about the level of stenosis in microanastomoses. Stenoses ranging between 30 and 85 percent of the cross-sectional area of carotid arteries were evaluated in rats. Peak systolic velocities were measured in prestenotic, stenotic, and poststenotic segments, using the duplex technique. Surgical results with duplex measurements were expressed as percentage of stenosis (calculated from a ratio of two cross-sectional areas), and later correlated. The correlation coefficient between the two sets of measurements was 0.82 (p < 0.01), and the hypothesis of a simple linear relationship was clearly accepted (p = 0.92). Results of the study show that duplex measurements become increasingly unreliable in stenoses with severity less than 50 percent. With increasing degrees of stenosis (50 percent and above), the variance of measurements with duplex decreases. According to the data, the limiting value for the duplex method appears to lie at about 85 percent. When methods for continuous measurement of flap perfusion indicate a hindrance of inflow, Doppler duplex can provide valuable information about the causes. This technique can be used clinically for the evaluation of microanastomoses in 1-mm vessels. In clinical cases, if a 50 percent or more stenosis is diagnosed by duplex technique, the measurement should be repeated within 1 to 2 hr. If the stenosis persists or intensifies, revision should be considered.

Evaluation of red blood cell and plasma flow and volume by the use of a dynamic and dual static acquisition radionuclide technique in arterial flaps in sheep

The aim of this study was to investigate whether in the distal, poorly perfused part of a flap the pressure gradient remains sufficient to allow flow of plasma and red blood cells (RBCs) within the first hour after flap elevation. For this purpose 99Tcm-labelled RBCs and 111In-chloride-labelled plasma proteins in an arterial skin flap that extended beyond the boundaries of its vascular territory in sheep has been used. Flow information was derived for both plasma and RBCs from dynamic acquisitions, while volume information was derived from dual energy static acquisition at equilibrium (steady-state). Results indicate that the mean flow and the mean volume of plasma are equal through the entire length of the flap. Although the flow is minimal, there is no stasis of plasma in the poorly perfused part of the flap. By comparing the mean flow of RBCs to their mean volume, no difference is seen in the well-perfused proximal two-thirds of the flap. In the distal, poorly perfused part, flow decreases while the volume increases. The increased volume of RBCs at minimal flow indicate pooling of RBCs in this region already in the first hour after flap elevation.

Effect of Ridogrel, a thromboxane receptor blocker and synthesis inhibitor on plasma and red blood cell flow in an arterial skin flap in sheep

This study evaluates the effect of the new combined thromboxane synthesis inhibitor and receptor blocker, ridogrel, on the circulation of arterial skin flaps in sheep. Sixteen flaps, 8 controls and 8 treated with 5 mg/kg ridogrel, were investigated using 111Indium chloride labelled plasma and 99mTc labelled red blood cells (RBCs). Dynamic imaging was performed after a bolus injection using a GE 400 AT gamma camera. For each flap quantitative analysis of plasma and RBC flow was based on time activity curves obtained from 12 regions of interest. Analysis of flow data was made immediately after flap elevation and three hours later. Both plasma and RBC flows declined after 3 hours. Treatment with ridogrel significantly prevented deterioration of perfusion by increasing plasma and RBC flow mostly in the distal, ischaemic regions of the flap where stasis was evident in the control flaps.

Evaluation of the microcirculation in a sheep island pedicle flap with laser Doppler flowmeter and 99m-Tc-labelled red blood cells

The aim of the study was experimentally to evaluate the capability and reliability of laser Doppler flowmetry (LDF) in conditions of circulatory deficiency, by correlating it to flow-related parameters measured by a radionuclide-imaging technique and using 99m-Tc red blood cells (RBCs). For this purpose, a pedicle island flap in the sheep was used, with well-perfused proximal parts and with evident stasis in the distal third of the flap. No correlation was found between results obtained with the two techniques. In regions with evident stasis, falsely high LDF readings were recorded. This may be due to a back-and-forth motion of the RBCs under the probe, rather than to true flow. It was concluded that, while LDF seems reliable in detecting complete arterial occlusion, it is unreliable in predicting either complete venous occlusion or partial obstruction of the flow to and from the flap. Clinical use for this purpose cannot be recommended.

A comparative study of the use of 9-0 PDS and 9-0 prolene in microvascular anastomosis

9-0 absorbable polydioxanone (PDS) has been compared to 9-0 nonabsorbable Prolene in order to evaluate any advantages of either suture in microvascular surgery. In each of 29 rats, one carotid artery was anastomosed end-to-end with PDS and the other with Prolene. Specimens were harvested 48 hr, 14 days, and three, and five months postoperatively. Histologic examination of the carotids followed postmortem using 4.5 x magnification angiography. Histologic analysis of inflammation, fibrosis, and medical necrosis of the anastomoses revealed no significant differences between the two materials. There was no difference as regards stenosis and aneurysm formation, when evaluated independently by the two methods. It was observed that saccular aneurysms formed as a result of medial necrosis and could develop at any time. Fusiform aneurysms formed where the media was replaced by bulging fibrosis and they appeared late. External support of adherent skeletal muscle prevented aneurysm formation. It can be concluded that the amount of inflammation and fibrosis leading to stenosis is related to the amount of trauma at the time of surgery and not to the type of suturing material used.

Magnification angiography and histology for the evaluation of microvascular anastomosis

Magnification angiography was compared with histology in order to assess the value of each of the two techniques for the evaluation of microvascular anastomoses. At postmortem, angiography of 108 end-to-end anastomoses of the rat carotid artery (4.5 X magnification) was performed, followed by histological examination. Each method assessed the degree of stenosis or aneurysmal dilatation independently, expressing it as a percentage of lumen change compared to a noninvolved vessel segment of the same artery. Results were plotted for each carotid separately. Both methods were found to be equally useful, but were of rather low sensitivity and specificity. Each failed to diagnose roughly one-third of all stenoses and even more aneurysms. A possibility for further improvement of the results is discussed. Both methods proved to be complementary; at least one-third of the vascular changes would have been missed if only one method had been used. A combination of both techniques should therefore be used in studies of microvascular anastomoses.

Radionuclide methodology for the assessment of the microcirculation in island pedicle flaps in a sheep model

Island pedicle flaps with a proximal well-perfused part and a distal poorly-perfused part were raised in eight anaesthetized sheep. Autologous red blood cells were labelled in vitro with 99TcmO4 and plasma with 111In chloride. The labelled cells and plasma were injected intraarterially and both dynamic and static images of the time-course of radioactivity were obtained with a gamma camera. Time activity curves were generated for selected regions of interest of the flap. For both plasma and red cells there was a substantial decline in the amount of tracer reaching the distal part of the flap; the time to maximum counts increased and the time activity curves indicated a minor uptake and almost no clearance pattern. In general there were marked local differences in the flow of plasma and red cells. The flow of plasma was more rapid than that of the red cells in five of the eight sheep. The model provides a standardized pedicle flap having a proximal part with adequate circulation and a distal part with inadequate circulation. It is concluded that this sheep model is suitable for radionuclide studies examining those factors that influence the distribution of blood flow within this tissue.

Latissimus dorsi free flaps for total repair of extensive lower leg injuries in children

A well-established belief is that with crushed and contaminated wounds closure should be delayed. However, an emergency procedure involving very thorough debridement, complete reconstruction of all injured tissues, and cover by a latissimus dorsi free flap in the same operation is evaluated in 15 children presenting with severe injuries to the lower limb. It is felt that the procedure is superior to the established method because it is a one-stage procedure that minimizes the danger of infection, prevents growth impairment, shortens hospitalization, and allows early mobilization, thus being, in some cases, a limb-saving procedure.