Primary or metastatic hepatic malignancies are life-threatening. Complete surgical resection is the only potentially curative treatment. In hepatic surgery, more important than what we remove is what we leave. The amount of remaining liver is paramount. At the end of the surgery, a patient must have at least two contiguous segments with both good blood inflow and outflow and with adequate biliary drainage.
The remaining liver volume, the Future Liver Remnant (FLR), is paramount to maintain function. In a normal functioning liver, a FLR of 25% is enough to live. In patients with hepatic dysfunction, an FLR of 40% is mandatory. However, “resectability” is not clearly defined. One interesting way to decide the "resectability" of a tumor is to estimate the FLR to body weight ratio, if it is >0,5 we can achieve a good “resectability”.
Radical resection is the only potentially curative treatment for primary or metastatic liver malignancies.
To overcome the “resectability” issue of some patients, hepatic resection strategies have been used. A 2-staged resection is one possible technique for bilateral disease. Another option is the occlusion of the portal vein (PV) in the tumor-bearing lobe, which will induce atrophy of the diseased lobe with hypertrophy of the contralateral lobe. Portal vein embolization (PVE) or surgical portal vein ligation (PVL) are both valid options with similar results. However, in some cases of PV occlusion, tumor progression occurs during the time gap between PV occlusion and surgery.
Associating Liver Partition and Portal vein Ligation for Staged hepatectomy (ALPPS) is a recent technique aiming at allowing extended hepatic resection in patients with limited functional reserve. ALPPS was first described in 2012 by Dr. Andreas Schnitzbauer from the University Hospital of Regensburg, Germany, and published in the Annals of Surgery. These authors from the group led by Dr Hans Schlitt described a novel concept of 2-staged extended right hepatectomy, with the first stage including right PVL and in situ splitting (ISS) along the right side of the falciform ligament. In this first report, the authors conducted a retrospective analysis of 25 patients and analyzed the increase in the volume of the left lobe from before ISS till immediately before the second surgery.
Future Liver Remnant is paramount to maintain function after resection.
ALPPS as it was first described:
Step 1 – first stage:
Exploratory laparotomy was conducted with intraoperative ultrasonography confirming resectability with a tumor-free left lobe.
The right portal vein was ligated and divided. All portal, arterial, and biliary branches for segment IV were ligated along the right rim of the round ligament.
The right liver lobe was completely mobilized, and a total or near-total parenchymal dissection was performed along the right side of the falciform ligament, completing the in-situ splitting (ISS). Branches to the segment I were only ligated if segment I was to be included in resection. After ISS, the extended right lobe (right liver) was covered in a plastic bag to prevent adhesions. Central venous pressure was always below 5 mmHg.
Step 2 – second surgery:
After 5-28 days (median of 9 days) a CT volumetry was conducted.
Completion surgery was performed on the same day or the next: right artery was ligated, biliary drainage was ligated, right and middle hepatic veins were divided, remaining parenchymal bridges were divided. In a minimum number of patients, an additional atypical resection of small nodules in segment II was performed. The left lobe was fixed to the abdominal wall to prevent malrotation.
Before the ISS, the median volume of the left lobe was 310 ml, with a median left lateral liver lobe to body weight ratio (LLLL/BW ratio) of 0,38, meaning there was a high risk of not having enough FLR to maintain function. Before the second surgery, the data recorded were impressive. After 9 days of ISS, the median volume of the left lobe was 536ml, meaning there was a 74% increase in left lobe volume. The mean LLLL/BW ratio was 0,61. I would like to highlight the fact that in one patient the volume of the left lobe increased 192%. Amazing the liver is. Do you remember Prometheus? He is the historical proof of the regeneration ability of this amazing organ. Schnitzbauer et al. also concluded that preoperative chemotherapy did not influence hypertrophy. This is very important, I think. Completion surgery was performed if LLLL/BW ratio was higher than 0,45. However, one female patient with LLLL/BW of 0,35 was submitted to resection surgery. Recovery was uneventful. Should that cut-off of 0.45 be an absolute indication?
ALPPS is a 2-staged hepatectomy.
The first stage combines PVL with in-situ splitting (ISS).
As the authors state, “the only chance to obtain long-term survival in patients with hepatic tumor or metastasis from other primary cancers is complete tumor resection in the liver”. This means surgery is the only curative treatment and all efforts must be done to accomplish an R0 resection. Other treatment options have limited indications and most of the time are offered to patients unfit for surgery. However, there are patients fit for surgery but with large tumors or small tumors in central locations, for whom the remaining liver volume after radical resection might not be enough to maintain function. In that setting, all strategies to increase FLR volume are welcome. PVE and PVL are both valid options. These techniques induce an increase in FLR volume up to 46% and 38-53% in 2-8 weeks, respectively. ALPPS described in 2012 for an extended right hepatectomy allows for a 75% hypertrophy of the left lobe within 9 days. So ALPPS induces faster and greater hypertrophy. Impressive!
One reason for the worse results with PVE and PVL is the formation of collaterals between the two liver lobes, and missing embolization of some branches for segment IV. By including in-situ splitting (ISS), ALPPS completely removes vascularization for segment IV and prevents collaterals to form between both lobes. According to the authors, the earlier occurrence of hypertrophy may be explained by an earlier liver regeneration rate peak following resection. In conclusion, both PVL (including left branches for segment IV) and ISS are responsible for the fantastic and impressive regeneration rate and increase in left liver lobe volume with the ALPPS.
ALPPS induces a faster and greater hypertrophy (75%) than PVL or PVE.
In 2012, Schnitzbauer et al. concluded that this was a heterogeneous group of patients, meaning more data were necessary to define which group of patients might benefit from ALPPS. An open mind is always necessary for medicine and surgery to evolve. Congrats to Schnitzbauer et al. for this innovation and for “thinking out of the box”. More lives may now be saved.
Link to PubMed:
Dr. Carlos Eduardo Costa Almeida
General Surgeon
#ALPPS #liver #liver_resection #hepatic_surgery #cancer #metastasis #metastases #future_liver_remnant #FLR #PVL #PVE #portal_vein_ligation #portal_vein_embolization #hepatocarcinoma