this 
 single centre series describes 40 laparoscopic liver procedures carried out 
 between september 1997 and november 2006 . included
are both anatomical and 
 nonanatomical laparoscopic resections for both malignant and benign tumours and 
 novel use of the microwave ablation probe on hepatocellular carcinoma and other 
 benign lesions .
operating times , resection margins , length of hospital stay , 
 amount of blood loss , and technical aspects of laparoscopic liver surgery are 
 discussed .
forty patients undergoing laparoscopic liver surgery by two surgeons 
 were identified from operating diaries between september 1997 and november 
 2006 .
information was gathered on a standard proforma retrospectively from 
 operating notes , anaesthetic charts , histology reports , hospital notes , 
 hospital computer systems , general practitioner records , and direct observation 
 of procedures .  
no patient was excluded and patients were selected for laparoscopic 
 surgery as having a lesion which was technically possible to resect or treat 
 laparoscopically whilst leaving an adequate resection margin where applicable . 
 in the case of patients with hepatic tumours ,
a standard multidisciplinary team 
 approach in regards to preoperative staging , treatment , and selection was 
 adopted .
patients selected for microwave ablation included : patients with hcc 
 who would not withstand formal liver resection due to poor hepatic function , 
 one patient undergoing laparoscopic left lateral lobectomy for a suspicious 
 lesion ( at operation suspected to be fnh ) , and a similar suspicious lesion in 
 segment 4a which was biopsied and then microwaved  this prevented a major 
 hemihepatectomy in a young patient for benign disease , an inaccessible 
 haemangioma in segment 7 , and a metastasis from a parathyroid carcinoma in 
 segment 4 preventing a major resection in a frail patient .
laparoscopic liver surgery was carried with most patients in a supine 
 low lloyd - davies position , some right sided lesions were accessed by 
 positioning the patient on their left side .
one surgeon ( dml ) used an open 
 approach for obtaining a pneumoperitoneum for all candidates including those 
 who had had prior midline laparotomies . the second surgeon ( gsr ) 

preferred to use a veress needle inserted at palmer 's point ( just 
 below the left costal margin in the midclavicular line ) , to insufflate the 
 abdomen and introduced a 5 mm laparoscope in the left upper quadrant to avoid 
 any adhesions whilst introducing the umbilical trocar in those with prior 
 midline laparotomies . in 
 patients with no prior surgery ,
carbon dioxide pressures were maintained 
 between 812 mmhg . in general 5 ports including two 10/12 ports to interchange the cavitronic 
 ultrasound surgical aspirator ( cusa ) ( valleylab tyco healthcare , boulder , colo , usa ) and camera 
 were used .
resections were carried out using the 
 harmonic scalpel ( ethicon endosurgery , cincinnati , ohio , usa ) 
 or argon beam coagulator ( valleylab tyco healthcare ) to cut through the 
 capsule , and cusa for parenchymal dissection in conjunction with an allports 
 vascular staple gun ( ethicon endosurgery ) , or a multiple clip applier for clipping 
 vessels .
the harmonic scalpel uses ultrasonic energy vibrating at 55 500 hz to allow precise cutting and focussed coaptive 
 coagulation allowing preservation of important structures such as bile ducts 
 and larger blood vessels .
coaptive coagulation requires a lower temperature 
 ( 50c to 100c ) than electrocautery or lasers to denature proteins in the 
 tissues forming a haemostatic protein coagulum which seals smaller blood 
 vessels , when the effect is prolonged , secondary heat is produced and can seal 
 larger vessels useful for fast effective haemostasis in laparoscopic 
 hepatectomy .
the argon beam coagulator is useful in laparoscopic hepatectomy as it may coagulate a 
 large area such as the cut surface of the liver after resection using lower 
 temperatures ( 50c to 104c ) than standard electrocautery , thus minimising eschar and damage to 
 important structures such as bile ducts and large vessels .
a single pringle manoeuvre was applied for 30 minutes during the laparoscopic 
 right hemihepatectomy , no other resections required a pringle manoeuvre and no 
 outflow control was necessary in any procedure .
intraoperative ultrasound ( bk medical , herlev , denmark ) was used to assess extent of 
 malignant tumours in all cases . at the end of the resection
, fibrin glue 
 ( johnson and johnson , cincinnati , oh , usa ) was used to seal the resection 
 site .
all tumours were sealed in a retrieval pouch ( espiner medical limited retrieval products , bristol , uk ) 
 or an endocatch ( autosutures , tyco healthcare , hampshire , uk ) 
 before removal from the abdomen . for microwave ablation
( microsulis medicial 
 limited , hampshire , uk ) the 5 mm probe was inserted 
 through a laparoscopic port and the ceramic tip of the probe inserted directly 
 into the lesion , microwaves were then radiated from the tip .
ablation progress 
 was monitored by real - time laparoscopic intraoperative ultrasound . at the end of 
 the operation ,
a tube drain is placed in the liver bed to monitor any 
 postoperative bile leaks .
when deroofing large liver and bile duct cysts a 
 portion of omentum is sutured into the defect to prevent bile leaks and a tube 
 drain is again left in situ for 
 postoperative monitoring .
forty - three procedures including 41 laparoscopic liver procedures on 40 
 patients were performed between september 1997 and november 2006 .
the mean age 
 of patient at operation was 59 years , 17/40 of patients were male and 23/40 
 were female .
benign lesions 
 treated included haemangiomas , liver cell adenoma , focal nodular hyperplasia , 
 and deroofing of liver cysts and a bile duct cyst .
microwave ablation was 
 utilised for hepatocellular carcinoma , haemangioma , metastatic parathyroid 
 carcinoma , and focal nodular hyperplasia .
three operations incorporated 
 multiple procedures these included a 74-year - old frail male patient who had a 
 right inguinal hernia repair immediately before proceeding to a planned segment 
 5 resection of a colorectal metastasis .
a 73-year - old male who had a wedge excision of a haemangioma in 
 segment 5 and microwave ablation of a second highly vascular haemangioma in 
 segment 6 , minimising the amount of tissue resected for benign disease . a 
 34-year - old female undergoing laparoscopic left lateral lobectomy for a 
 suspicious lesion thought to be fnh , with a similar suspicious lesion found in 
 segment 4a , intraoperative frozen section confirmed this lesion also to be fnh 
 and a successful microwave ablation was performed preventing a formal hemihepatectomy in a 
 young patient with benign disease .
the operations included right 
 hemihepatectomy n = 1 , ( a second right hemihepatectomy was aborted due to 
 widespread peritoneal disease following an exploratory laparoscopy n = 1 ) , left 
 lateral lobectomy n = 4 , bisegmentectomy n = 2 , segmetectomy n = 8 , wedge resection 
 n = 11 , microwave ablation n = 8 , and deroofing of liver and bile duct cysts n = 7 , 
 right inguinal hernia repair n = 1 .
table 1 describes the demographic , 
 intraoperative and postoperative details of all the patients .
median operating time for the entire group of patients as judged by 
 length of time under general anaesthetic in theatre was 120 minutes ( range 40240 minutes ) . 
 mean blood loss was 78 ml and only one patient required transfusion .
conversion 
 to open operation was carried out in 1 out of 40 patients ; this was a segment 5 
 resection for a colorectal metastasis and was due to cusa failure .
median operating time excluding patients having only cyst deroofing or 
 microwave ablation , and excluding the patient who was converted to open hepatectomy 
 and the patient having a failed right hemihepatectomy due to the presence of 
 peritoneal metastasis , was unchanged at 120 minutes ( range 60240 minutes ) , 
 mean blood loss was 104 ml , and median length of stay remained 3 days for this 
 group .
median resection margins given by the pathologist were 10 mm ( range 145 mm ) , where 
 actual resection margins were not given malignant lesions were described as 
 completely excised ( ce ) .
of the 17 
 malignant tumours , one patient has died of coronary artery disease and one 
 patient who had a segment 5 resection of colorectal liver metastasis has 
 developed lung metastases .
the benefits and indications for laparoscopic liver surgery have yet to 
 be fully established .
the first reported laparoscopic liver resection was 
 undertaken in 1991 for a benign lesion . since then data from a recent 

review suggests that most laparoscopic resections 
 have been nonanatomical or simple wedge resections or cyst fenestration and deroofing 
 for liver cysts .
left lateral lobectomy ( couinaud segments 2 and 3 ) has 
 been carried out and also more rarely formal left or right hemihepatectomy .
approximately 70% of resections have been 
 carried out for benign lesions and 30% malignant lesions .
laparoscopic liver surgery is a developing field and our experience and 
 learning curve together with a discussion pertaining to indications , safety , 
 and efficacy of laparoscopic hepatic resection and technical aspects of the 
 surgery is presented .
the first laparoscopic liver resection at our institution was a left 
 lateral lobectomy in 1997 for focal nodular hyperplasia . since then the number 
 of hepatic resections carried out laparoscopically
lesions selected for laparoscopic resection at our institution are in 
 the easily accessible segments : 2 , 3 , 4a , 5 , and 6 well away from the major 
 hepatic veins .
these lesions are often visible on the liver surface and well 
 characterised by saggital and coronal magnetic resonance images .
initially only 
 benign lesions were resected due to concerns regarding oncological adequacy of 
 laparoscopic resection margins and the risk of tumour seeding in the port sites . 

the publication of the conventional versus laparoscopic - assisted surgery in 
 patients with colorectal cancer ( clasicc ) trial verified that there were no 
 significant differences between open surgery and laparoscopic - assisted 
 colorectal tumour excision with respect to tumour and nodal status , therefore , 
 laparoscopic surgery in relation to excision of malignant hepatic tumours 
 seemed justified .
microwave ablation has been under investigation by the authors for the 
 treatment of liver tumours in both animal models and human patients [ 810 ] . 

the indications for the use of microwave ablation are , as yet , not clearly 
 defined though patients with hcc who could not withstand a formal hepatectomy 
 due to loss of hepatic tissue , symptomatic benign tumours ( excluding liver cell 
 adenoma ) , unusual single liver tumours , and patients with tumour recurrence in 
 a liver that has previously undergone a resection are all potential candidates 
 and have been described in this series .
one large seriesreports 
 median resection margins of 5 and 10 mm for colorectal metastasis and hcc , respectively 
 .
usage of the intraoperative ultrasound probe has been shown by gigot et al .   to improve adequacy of 
 resection margin . the intraoperative ultrasound probe is therefore used 
 routinely in our establishment when resecting malignant tumours .
there are currently no randomised controlled trials comparing open and 
 laparoscopic hepatectomy but several small nonrandomised comparative trials 
 have suggested that 
 there is no difference in adequacy of resection margin between open and 
 laparoscopic hepatectomy [ 1215 ] .
the median resection margin for 
 malignant tumours in this study is 10 mm and there has been no local recurrence . 

recent studies have now suggested that the width of a negative resection margin 
 does not affect survival , recurrence risk , or site of recurrence for colorectal 
 metastasis .
it is of note that anatomical resections for colorectal 
 metastases have also not been shown to be superior to wedge resections as long 
 as the tumour is clear at the resection margins .
abdominal wall metastasis at port sites has been reported after 
 laparoscopic surgery for malignant tumours .
recent data has shown that there is no 
 difference in wound - site tumour recurrence between open and laparoscopic 
 colorectal surgery for if conventional 
 oncological techniques such as no touch technique and sealing resected 
 specimens in retrieval pouches before removal are employed , rates should be 
 less than 1% .
some surgeons have raised concerns for the possibility of gas embolism 
 due to transection of low pressure veins under pneumoperitoneum .
this has led 
 some centres to adopt a gasless laparoscopy technique , whereby intra - abdominal 
 space is created by abdominal suspension techniques .
others have used a 
 lower pressure carbon dioxide pneumoperitoneum , maintained between 1012 mmhg 
 [ 4 , 12 ] .
usage of the argon beam coagulator in both laparoscopic cholecystectomy 
 and laparoscopic liver surgery has been associated with a clinical diagnosis of 
 venous gas embolism in several case reports [ 2123 ] .
a recent review 
 suggests that the incidence of clinical gas embolism in 700 laparoscopic liver procedures carried 
 out worldwide is reportedly 0.3% .
it is , however , of interest that 
 following laparoscopic cholescystectomy intravascular gas bubbles have been 
 routinely observed using transoesophageal echocardiography ; this does not seem 
 to correlate with the clinical picture of gas embolism .
an experimental study assessing the usage of argon - enhanced coagulation 
 of cut sections of liver in a porcine model , whereby gas emboli were detected 
 using a doppler flow cuff around the caudal vena cava , demonstrated that the 
 number of gas emboli produced increased with increasing gas flow rates but was 
 not affected by coagulation power .
this study recommended that surgeons and 
 anaesthetists should be aware that there is a potential to develop a clinically important gas 
 embolism and that adequate precautions should be taken to prevent this such as 
 selecting a low flow setting on the argon beam coagulator and adequate venting 
 of the abdomen through chimneys in laparoscopic ports to maintain safe 
 pressures of between 812 mmhg . 

these measures have been adopted at our institution where argon gas flow is set 
 to 4 l / min ( low flow ) on the laparoscopic setting which incorporates an alarm if 
 intra - abdominal pressures exceed preselected limits12 mmhg for 
 laparoscopic hepatectomy which alerts the surgeon who can open the port chimney to vent the abdomen .
no 
 clinical signs of gas embolism have been observed in association with the argon 
 beam coagulator .
hepatectomy can be associated with severe haemorrhage and a 
 major concern to some is the threat of uncontrollable haemorrhage with minimal 
 access to the abdomen .
this series presents an extremely low operative blood 
 loss rate with a mean blood loss of 78 ml .
it is worthwhile noting that where 
 laparoscopic liver resections are converted to open procedures it is often due 
 to bleeding . in general , some studies comparing laparoscopic versus open procedures 
 have demonstrated that the laparoscopic approach may well be associated with 
 less blood loss than open equivalents [ 14 , 26 ] .
this observation may be due 
 to the tamponading effect of a pneumoperitoneum and the anaesthetists at our 
 institution raise the central venous pressure to between 710 mmhg whilst 
 the surgeons decrease the carbon dioxide insufflation pressure at the end of 
 all laparoscopic liver procedures in order to assess safely for haemostasis . 

additional anaesthetic considerations pertaining to laparoscopic liver surgery 
 include initially running a lower central venous pressure of 1 - 2 mmhg to 
 decrease bleeding and placement of a central line for central venous pressure 
 monitoring , but an epidural is not required as postoperative analgesia 
 requirements are usually confined to oral preparations .
the final consideration for safe laparoscopic surgery pertains to 
 technical ability and experience of the surgeon .
it is recommended by the 
 specialist advisory committee to the national institute of clinical excellence 
 that laparoscopic liver resections should only be carried out in specialist 
 centres and by those with advanced skills in hepatic resection and laparoscopy 
 .
it is also apparent that the lesions most suitable for laparoscopic 
 resection are those situated in the left lateral and right anterior segments 
 away from the main hepatic veins this in turn reduces the risk of serious 
 haemorrhage . in conclusion
patients experience a shorter hospital stay , 
 minimal blood loss , shorter operation time , and short - term data indicates 
 equivalent oncological results when compared with conventional open 
 hepatectomy .
randomised controlled trials assessing the oncological efficacy of 
 laparoscopic and open hepatectomy for selected lesions are indicated at this 
 stage .
 
 objective . this series describes a developing experience in laparoscopic liver surgery presenting results from 40 procedures including right hemihepatectomy , left lateral lobectomy , and microwave ablation therapy . 
 methods . 
 forty patients undergoing laparoscopic liver surgery between september 1997 and november 2006 were included . 
 the data set includes : operative procedure and duration , intraoperative blood loss , conversion to open operation rates , length of hospital stay , complications , mortality , histology of lesions / resection margins , and disease recurrence 
 . results . 
 mean age of patient : 59 years , 17/40 male , 23/40 female , 23/40 of lesions were benign , and 17/40 malignant . 
 operations included : laparoscopic anatomical resections n = 15 , nonanatomical resections n = 11 , microwave ablations n = 8 and deroofing of cysts n = 7 . 
 median anaesthetic time : 120 minutes ( range 40240 ) , mean blood loss 78 ml and 1/40 conversions to open . 
 median resection margins were 10 mm ( range 114 ) and median length of stay 3 days ( range 110 ) . 
 operative and 30-day mortality were zero with no local disease recurrence . 
 conclusion . 
 laparoscopic liver surgery appears safe and effective and is associated with reduced hospital stay . 
 larger studies are required to confirm it is oncologically sound . 
1. INTRODUCTION
2. PATIENTS AND METHODS
3. RESULTS AND DISCUSSION
4. DISCUSSION