Volume function planning in liver surgery

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Liver tumors such as hepatocellular carcinoma or colorectal liver metastases can be treated curatively by liver surgery with removal of the diseased liver parenchyma . Not all patients can cope with such a liver resection due to certain previous illnesses . The decisive criterion for operability is that there is still enough functional liver tissue left to fulfill the physiological functions of the liver after the operation. Preoperative volume function planning in liver surgery is used to determine the residual liver function to be expected after the operation (FLRF, Future Liver Remnant Function ) and is used in the clinic to assess the risk of postoperative liver failure ( posthepatectomy liver failure , PHLF). The fundamental aim is the reliable identification of those patients in whom a liver resection can be carried out with as few complications as possible.

description

To determine the FLRF, the liver function is determined using the LiMAx test and combined with a cross-sectional image-based ( CT , MRT ) liver volume calculation. There are other methods for dynamic liver function measurement whose application for volume function planning has not yet been researched in detail. In detail, according to Stockmann et al., With preoperative LiMAx values ​​of ≥315 µg / kg / h major resections (> 4 segments) are classified as safely feasible. If the preoperative LiMAx values ​​are low in the range 140–314 µg / kg / h, a preoperative volume-function analysis is indicated, since these patients end up in a critically low liver function area after the operation and therefore have an increased risk of postoperative complications (including PHLF ) wear. In these cases, the most exact possible preoperative survey of the FLRF is desirable for the best possible support for surgical decision-making.

The confirmation that there is a significant correlation (r = 0.85, p <0.001) between the preoperative prediction of the FLRF and the actual FLRF, measured within 24 h after the operation, was also provided by Stockmann et al. provided. On average, there was a difference (± standard deviation ) of −36 ± 43 µg / kg / h between the LiMAx predicted preoperatively and the one actually measured postoperatively. The study by Malinowski et al. who discusses intraoperative ischemia and postoperative hypoperfusion of individual liver areas as possible causes of the discrepancy between preoperative prediction of FLRF and actually measured postoperatively function and proposes the introduction of a "safety interval". A further influence on the FLRF could be the presence of residual CYP1A2 activity in tumorous liver tissues, the CYP1A2 activity of which is mentioned above. Formula with 0 is assumed. A study by Wuensch et al. was able to show in this regard that the residual CYP1A2 activity in tumorous liver tissue ( hepatocellular carcinoma , colorectal liver metastases ) is negligibly low (<2% of the CYP1A2 activity in healthy liver tissue), while the residual CYP1A2 activity in hepatocellular adenoma tissue is approx. 12% the CYP1A2 activity in healthy liver tissue, has a more pronounced influence on the overall CYP1A2 liver performance. These data confirm that the calculation of the residual liver function in cases of hepatocellular carcinoma and colorectal liver metastases using the above formula provides an accurate prediction.

Exemplary representation of an MRT scan with marking of the total area of ​​the liver (yellow), the tumor area (red) and the remaining area of ​​the liver (green). For the volumetric calculation, all sectional images are marked analogously to the example and the volumes of the entire liver (V G ), the tumor (V T ) and the residual liver after surgery (V FLRV ) are determined using software .

Methodical approach and calculation

To determine the residual liver function, the total liver volume (V G ) is first identified from sectional images using suitable software . Then the tumorous area (V T ) is marked and the surgical cut surface is drawn in, which enables the division into resected tissue (V R ) and residual liver volume (V FLRV , Future Liver Remnant Volume) (Figure 1). The dedicated procedure just described is necessary because it is assumed that the tumorous volume has no CYP1A2 activity and thus does not contribute to the overall liver function determined using LiMAx. The following formula is used to calculate the FLRF:

With a calculated residual liver function (FLRF) of> 100 µg / kg / h, the procedure can be assumed to be safe for the patient, while an FLRF between 80 and 100 µg / kg / h is associated with an increased risk and with a FLRF <80 µg / kg / h should not be operated on at all (38.1% postoperative mortality).

Clinical application

An evaluation of patient data could show that the residual postoperative liver function anticipated by means of LiMAx and imaging has predictive value both for immediately postoperative complications and for PHLF. In addition, it was able to prove that the use of the LiMAx test actually contributes to improving patient care in liver surgery. In a retrospective analysis of 1170 patients who underwent elective hepatectomy between 2006 and 2011, it could be shown that the rate of postoperative liver failure and the associated mortality decreased significantly after the implementation of the LiMAx decision algorithm. In a randomized controlled multicenter study, surgical patients with intrahepatic tumors were either treated according to the prevailing clinical standard (control group) or received two perioperative LiMAx tests (intervention group). The preoperative LiMAx test was used for preoperative risk assessment (including volume and function planning) and surgical planning in accordance with the LiMAx algorithm and the postoperative LiMAx test to optimize postoperative treatment. The rate of severe complications was significantly reduced in the intervention group, while the overall length of stay in hospital and length of stay in the intensive care unit were significantly reduced on average.

Individual evidence

  1. ^ Nuh N. Rahbari, O. James Garden, Robert Padbury, Mark Brooke-Smith, Michael Crawford: Posthepatectomy liver failure: A definition and grading by the International Study Group of Liver Surgery (ISGLS) . In: Surgery . tape 149 , no. 5 , 2011, p. 713-724 , doi : 10.1016 / j.surg.2010.10.001 ( elsevier.com [accessed June 7, 2019]).
  2. ↑ a b Martin Stockmann , Johan F. Lock, Björn Riecke, Karsten Heyne, Peter Martus: Prediction of Postoperative Outcome After Hepatectomy With a New Bedside Test for Maximal Liver Function Capacity . In: Annals of Surgery . tape 250 , no. 1 , July 2009, ISSN  0003-4932 , p. 119-125 , doi : 10.1097 / sla.0b013e3181ad85b5 .
  3. ↑ a b Martin Stockmann, Johan F. Lock, Maciej Malinowski, Stefan M. Niehues, Daniel Seehofer: The LiMAx test: a new liver function test for predicting postoperative outcome in liver surgery . In: HPB . tape 12 , no. 2 , March 2010, ISSN  1365-182X , p. 139-146 , doi : 10.1111 / j.1477-2574.2009.00151.x .
  4. ↑ a b c Maciej Malinowski, Johan Friso Lock, Daniel Seehofer, Bernhard Gebauer, Antje Schulz: Preliminary study on liver function changes after trisectionectomy with versus without prior portal vein embolization . In: Surgery Today . tape 46 , no. 9 , December 31, 2015, ISSN  0941-1291 , p. 1053-1061 , doi : 10.1007 / s00595-015-1293-1 .
  5. ↑ Tilo Wuensch, Niklas Heucke, Jonas Wizenty, Janina Quint, Bruno Sinn: Hepatic CYP1A2 activity in liver tumors and the implications for preoperative volume-function analysis . In: American Journal of Physiology-Gastrointestinal and Liver Physiology . tape 316 , no. 5 , May 2019, ISSN  0193-1857 , p. G608 – G614 , doi : 10.1152 / ajpgi.00335.2018 .
  6. ↑ Elisabeth Blüthner, Maximilian Jara, Ritesh Shrestha, Wladimir Faber, Johann Pratschke: The predictive value of future liver remnant function after liver resection for HCC in noncirrhotic and cirrhotic patients . In: HPB . February 2019, ISSN  1365-182X , doi : 10.1016 / j.hpb.2018.11.012 .
  7. ↑ Maximilian Jara, Tim Reese, Maciej Malinowski, Erika Valle, Daniel Seehofer: Reductions in post ‐ hepatectomy liver failure and related mortality after implementation of the LiMAx algorithm in preoperative work ‐ up: a single ‐ center analysis of 1170 hepatectomies of one or more segments . In: HPB . tape 17 , no. 7 , July 2015, ISSN  1365-182X , p. 651-658 , doi : 10.1111 / hpb.12424 .
  8. ↑ M. Stockmann, FWR Vondran, R. Fahrner, HM Tautenhahn, J. Mittler: Randomized clinical trial comparing liver resection with and without perioperative assessment of liver function . In: BJS Open . tape 2 , no. 5 , June 14, 2018, ISSN  2474-9842 , p. 301-309 , doi : 10.1002 / bjs5.81 .