This document describes the use of microdialysis catheters to monitor free flaps in reconstructive surgery at Aarhus University Hospital in Denmark. It presents two case studies where microdialysis detected issues with free flaps earlier than clinical observation alone. In the first case, microdialysis identified a problem with venous outflow in a fibula flap that was corrected surgically. In the second case, microdialysis found an issue with arterial inflow in a muscle flap that also required reoperation. The document advocates for microdialysis as an objective and sensitive monitoring method that can facilitate early intervention to save compromised free flaps.

1. LENA KEHR 2015
exempel på genomförda
formgivningsprojekt
CMA Microdialysis
grafisk profil & logotyp
www.microdialysis.com

2. LENA KEHR 2015
exempel på genomförda
formgivningsprojekt
CMA Microdialysis
grafisk profil & loogotyp

3. LENA KEHR 2015
exempel på genomförda
formgivningsprojekt
CMA Microdialysis
produktkatalog 76 sidor
mobil utställningsmonter

4. LENA KEHR 2015
exempel på genomförda
formgivningsprojekt
CMA Microdialysis
CMA Microdialysis
25 års jubileum
logotype
stickers
clip
bag

5. exempel på medicinska illustrationer

6. LENA KEHR 2015
exempel på genomförda
formgivningsprojekt
MDialysis
modifierad katalog
ny design omslag och av
sidor i inlaga
design applikatonsblad
foldrar
broschyrer
www.mdialysis.com
Ref.No.8011142CJan2014
Literature:
Clinical studies listed below demonstrate that the concentra-
tion of glucose decreases in a flap during ischemia while the
concentrations of lactate and glycerol rise. These metabolic
changes indicate ischemia at an early stage, often hours before
clinical signs become evident. When the perfusion in the flap is
restituted e.g. by surgical intervention the Microdialysis values
return to normal levels.
Microdialysis in clinical practice: monitoring intraoral free flaps.
Ann Plast Surg. 2006 Apr;56(4):387-93. Jyränki J. et al
Department of Plastic Surgery, Helsinki University Hospital,
Helsinki, Finland.
Tracheostomy tape: more trouble than it’s worth?
Int J Oral Maxillofac Surg. 2007 Jun;36(6):550-1.
Case report Burke GA et al, Maxillofacial Unit, University Hospital Bir-
mingham, Birmingham, UK
Microdialysis: use in the assessment of a buried bone-only fibular
free flap.
Plast Reconstr Surg. 2007 Oct;120(5):1363-6.
Case report Mourouzis C et al, Department of Oral and Maxillofacial
Surgery, Queen Alexandra Hospital, Portsmouth, UK
Cost Analysis of 109 Microsurgical Reconstructions and Flap
Monitoring with Microdialysis
J Reconstr Microsurg. 2009 Nov;25(9):521-6.
Setälä L et al, Department of Plastic Surgery, Kuopio University
Hospital, Finland.
Pure Muscle Transfers Can Be Monitored by Use of Microdialysis
J Reconstr Microsurg. 2010 Nov;26(9):623-30.
Birke-Sorensen et al, Department of Plastic Surgery, Aarhus
University Hospital, Aarhus, Denmark.
Glucose and lactate metabolism in well-perfused and compro-
mised microvascular flaps.
J Reconstr Microsurg. 2013 Oct;29(8):505-10. doi: 10.1055/s-
0033-1348039. Setala et al. Department of Plastic Surgery, Kuopio
University Hospital, Finland.
M Dialysis AB
M Dialysis is the leading company devoted to the development, manufacturing and
marketing of the Microdialysis technique.
The head office is located in Stockholm, Sweden, with a subsidiary in Boston MA, USA.
M Dialysis has distributors across the globe, responsible for local sales, service and
support.
M Dialysis AB, Box 5049, SE-121 05 Stockholm, Sweden,
Tel: +46 8 470 10 20, Fax: +46-8-470 10 55
E-mail: info@mdialysis.se, www.mdialysis.com
Distributor
Flow chart
Reference:
Pure Muscle Transfers Can Be Monitored by Use of Microdialysis
J Reconstr Microsurg. 2010 Nov;26(9):623-30.
Birke-Sorensen et al, Department of Plastic Surgery, Aarhus University Hospital, Aarhus, Denmark.
Reconstructive Surgery
Microdialysis
casereport1
M Dialysis AB, Box 5049, SE-121 05 Stockholm, Sweden
Tel: +46 8 470 10 20, Fax: +46-8-470 10 55, E-mail: info@mdialysis.se, www.mdialysis.com
A free osteocutaneous
fibula flap monitored by
clinical observations and
Microdialysis.
Introduction
Microdialysis has been the method of monitoring free flaps in the Department of Plastic Surgery, Århus University Hospital since Septem-
ber 1998. In the beginning free flaps were monitored both with microdialysis and clinically. From 2000 microdialysis has been the routine
method of monitoring, and based on clinical experience, it has been possible to identify normal as well as
critical values for the different free flaps.
Case story
A twenty year old man with a sarcoma in the right mandible was referred for surgical treatment.
Operation
The operation was performed with two surgical teams working in parallel.The ablative team removed the cancer including almost half of
the mandible.The reconstructive team was operating on the left leg, preparing an osteo-cutaneous fibula flap.
In the neck the right facial artery and vein were selected as recipient vessels, and they were prepared to anastomose.
The free flap was taken to the neck.The fibula was fractured to form a new left side of the mandible.The vessels were anastomosed end-
to-end using double vessel clamps and nylon 9-0 interrupted sutures. After removing the clamps perfusion of the free flap was seen with
palpable pulse peripheral in the free flap and bleeding from bone as well as the skin island.The skin island was sutured in place intra-orally,
and the incisions in the face and neck were closed.
Microdialysis
To monitor the free flap a 60 Microdialysis Catheter was placed in the subcutaneous tissue of the skin island. Before the
patient left the operating room analysis were made of the first dialysates.
Postoperative observation plan
The free flap was observed every 30 minutes by both the clinical control of the free flap and analysis of microdialysis values.
Two hours postoperatively the micro-dialysis values were pathological, but clinically there were no signs of ischemia or
venous obstruction.
The flap was pink with a normal capillary refill. the face and neck were closed.
Re-operation decided
During the next hours the microdialysis values deteriorated with a high lactate and low glucose. However, no clinical signs of flap ischemia.
A decision was taken to re-operate and explore the anstomosing vessels and the anastomoses, fig.1 (see next page).
Re-operation
At the re-operation the anastomoses was found to be all right, but the recipient vein was bent in such a way, that no blood could leave the
flap.The vein was opened, and large amounts of thrombus material was withdrawn from the lumen.The vein was shortened and a new
anastomosis was performed. After half an hour the vein still had a good function, and the re-operation was completed. Before the patient
left the operating room, microdialysis values were normalized with a decrease in lactate and an increase in glucose, fig 2 (see next page).
The venous obstruction was never detected by clinical signs or observations in the flap.
After surgery
The young man did well and could go home after 10 days.The free osteocutaneous fibula flap survived and healing was found at control
after 4 months.
Microdialysis monitoring in Plastic Surgery
Hanne Birke Sørensen, MD, Consultant, Department of Plastic Surgery,
Århus University Hospital, Denmark
casereport2
A free muscle flap monitored
with Microdialysis.
Microdialysis monitoring in Plastic Surgery
Hanne Birke Sørensen, MD, Consultant, Department of Plastic Surgery,
Århus University Hospital, Denmark
Introduction
Microdialysis has been the method of choice for monitoring free flaps in Århus University Hospital since September 1998. In the
beginning the free flaps were monitored with microdialysis and clinical observation. From the beginning of 2000 microdialysis has
been the routine method of monitoring, and based on clinical experiences, it has been possible during this period to identify normal
as well as critical values for the different sorts of free flaps.
Case story
A 71-year-old man with an open fracture of the right tibia was referred to the Plastic Surgery department in March 2004 for soft tis-
sue covering of the fracture. At the time of operation the fracture was 5 weeks old, but unstable despite external fixation. The patient
was diabetic and suffered from arterial hypertension.
Operation
The operation was performed with the patient in general anaesthesia combined with epidural analgesia. At the right leg the wound
and the fracture was revised and stabilized. The posterior tibial artery and vein were dissected free proximal to the fracture. At the
abdomen the left rectus abdominis muscle was prepared as a free flap based on the inferior epigastric vessels. The muscle was
taken to the leg and the anastomoses were performed end-to-end using Ackland clamps and interrupted sutures. After removing
the clamps there was no pulse distally in the flap, but bleeding was observed in the peripheral part of the flap, and the situation
seemed acceptable. The muscle was folded on itself and could easily cover the fracture as well as the vessels. Split skin grafts
were harvested at the right femur for later use.
Microdialysis
A 60 Microdialysis Catheter was placed in the medial part of the flap passing through the adjacent skin. Before the patient left the operating
room an analysis was made of the first dialysates which showed normal values.
Postoperative observation plan
The Surgeons were confident with using Microdialysis as the only monitoring tool, therefore the free flap was covered up with no
plans for an inspection of the flap until the following day when they were to put on the split skin.
Analysis of microdialysates was made every 30 minutes for the next 24 hours.
Re-operation decided
During the first four hours postoperatively the microdialysis values changed pathologically; glucose decreased rapidly and lactate
increased to more than 20 mM, fig. 1 (see other side). The patient was stable with respect to pulse and blood pressure. The muscle
flap was covered up and the leg was elevated. Based on the Microdialysis data the decision was made to re-operate.
Re-operation
In the operating room the leg was unwrapped. The free muscle flap clinically looked satisfactory without any signs of ischemia or
venous obstruction. There was still bleeding from the peripheral part. The vessels were inspected thoroughly and no flow was seen
in the posterior tibial artery, meaning that bleeding from the flap had to be based on venous inflow from the posterior tibial vein with
insufficient valves. The artery was dissected 5 centimeters further proximally and a new anastomosis was performed. Immediately
there was good perfusion of the free flap and a pulse in the very distal part of the flap. A new vein anastomosis was performed
since the flap had to be placed further proximally. Before leaving the operating room glucose and lactate values were thoroughly
improving fig. 2 (see other side).
After Surgery
The next day the split skin was put on the muscle and it healed well except for 5 % where a new split skin graft was put on a couple
of weeks later.
M Dialysis AB, Box 5049, SE-121 05 Stockholm, Sweden
Tel: +46 8 470 10 20, Fax: +46-8-470 10 55,E-mail: info@mdialysis.se, www.mdialysis.com
Saving free flaps, reducing
healthcare costs
Monitoring metabolic markers with Microdialysis
Following microvascular free flap surgery, it is essential to monitor the perfusion of the transferred flap
because of the risk of anastomotic failure and ischemia. Monitoring of the flap is commonly made by
clinical observation of signs that appear following arterial or venous ischemia.
Metabolic monitoring offers early signs of complications
Microdialysis is a unique technique, which offers the possibility to continuously monitor the metabolism of the flap. Ischemia can be
detected by monitoring the changes in Glucose, Lactate, and Pyruvate levels in interstitial fluid of the specific tissue.1
Microdialysis
can reliably detect flap ischemia at an early stage.2
The performance of the analysis is easy and can be done by even less experienced nursing staff working in institutes with a low
frequency of microsurgery. 2
Excellent studies confirm results
In a recent Finnish study2
Microdialysis was used in the follow-up of 80 consecutive microvascular flaps. The salvage rate of all
thrombosed flaps was 77 percent, with a final success rate in microvascular reconstruction of 95 percent. No flap was lost due to
a delay in the diagnosis of secondary ischemia, if on-line Microdialysis monitoring was available. All thromboses were clearly rec-
ognized by Microdialysis via a decrease in the Glucose concentration in the tissue and an increase in the Lactate concentrations.
In another Finnish prospective study1 twenty-five consecutive patients who underwent oral cavity/oropharynx cancer resection and
immediate reconstruction with free flaps were monitored with Microdialysis. Two flaps out of 25 failed in spite of reoperations. In both
problem cases, Microdialysis indicated ischemia 1 to 2 hours before it became clinically evident. During flap ischemia, the Lactate/
Pyruvate ratio increased to a level clearly above 25, and at the same time the Glucose concentration diminished and remained below
0.4 mmol/L, whereas the Lactate level increased.
Microdialysis has several advantages compared to other monitoring techniques: objective measurements, different curves for ve-
nous and arterial thrombosis and early diagnosis. 3
It is a clinically feasible and sensitive monitoring method for all kinds of microvas-
cular flaps, especially for those in which clinical observation is difficult or impossible.2
In a Danish study4
fourteen women who underwent reconstruction with a free TRAM flap were monitored with Microdialysis. During
flap ischemia, the concentration of Glucose was reduced, while the Lactate and Glycerol levels increased. The differences between
the flaps and controls were statistically highly significant. The study concluded that Microdialysis could detect ischemia in free flaps
at an early stage making early surgical intervention possible.
MicrodialysisinPlasticSurgery
August2013
applicationnote7
M Dialysis AB, Box 5049 SE-121 05 Stockholm, Sweden
Tel: +46 8 470 10 20, Fax: +46-8-470 10 55, E-mail: info@mdialysis.se, www.mdialysis.com
Flowchart for monitoring
free flaps by use of
Microdialysis
if
• Glucose < 1 mmol/l
• Lactate > 10 mmol
• Ischemic trend
Go to Level-1 alarm
if
the ischemic trend
can be reverted
Return to standard
monitoring
Level-2 alarm
• Prepare the patient for
re-operation with exploration
of the pedicle and the
anastomosis
Level-1 alarm
• Evalution of the patient
• Evalution of the free flap
• 20 min sampling frequency
Action is taken in case of
• Inappropriate positioning
• Low blood pressure etc.
Standard monitoring
For the next 24 hours
MD-analysis every hour
For the first 24 hours
MD-analysis every 30 min
Introduction
“Microdialysis has been the standard procedure for surveillance of all free flaps at our Department of Plastic Surgery since 1998.
We analyze glucose, lactate, pyruvate and glycerol every half hour for the first 24 hours and with longer intervals until removal of
the catheter after 5 days. Glucose, lactate and glycerol are the main metabolites of significance. Standard alarm limits for evalu-
ation of the patient and the flap are: glucose below 1 mM and lactate above 10 mM or a clear trend in the values. Standard alarm
limits for re operation are:
Glucose below 0.1 mM and lactate above 15 mM or continuously ischemic trend without effect of interaction.”
Dr. Hanne Birke Sorensen,
Department of Plastic Surgery, Aarhus University Hospital, Aarhus, Denmark
Flowchart
if
Glucose < 0.1 mmol/l
Lactate > 15 mmol/l
Critical ischemic trend
Go to Level-2 alarm
if
the free flap is
revascularized
Return to standard
monotoring
For the following 2-3 days
MD-analysis every 2 hours
M Dialysis AB, Box 5049 SE-121 105Stockholm, Sweden
Tel: +46 8 470 10 20, Fax: +46-8-470 10 55, E-mail: info@mdialysis.se, www.mdialysis.com
MicrodialysisinPlasticSurgery
February2012
applicationnote10

7. LENA KEHR 2015
exempel på genomförda
formgivningsprojekt
MDialysis
mobil monter
www.mdialysis.com