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SURGICAL WEBSITES BREAST DISEASE LIVER ABSCESS Anatomy of liver SURGICAL WEBSITES KIDNEY SURGERY POSTGRADUATE SURGERY LINKS
BREAST DISEASE Breast cancer Breast lump Breast awareness Breast calcifications Breast cysts Breast pain Duct ectasia Fat necrosis Fibroadenoma Hyperplasia Intraductal papilloma Phyllodes tumour Sclerosing adenosis
LIVER ABSCESS Anatomy of liver Physiology of liver Method of examination of liver Haematology of liver disease. Amoebic liver abscess .Pyogenic liver abscess. Percutaneous needle aspiration of liver abscess. Case study. Result Result continued Discussion
CHOLECYSTECTOMY Introduction Historical Review Anatomy of Gallbladder Physiology of Gallbladder Physiologic effects of pneumoperitoneum Pathology of Gallbladder Investigations Pre- operative preparation of laparoscopic cholecystectomy Contraindications Treatment modalities for gallstones. Anaesthesia
INGUINAL HERNIA HOW SURGICAL OPERATION IS DONE THYROID EXAMINATION MANAGEMENT OF SEVERELY INJURED PATIENT SEPSIS AND MULTIPLE ORGAN FAILURE CHEST TRAUMA BRONCHOGENIC CARCINOMA TETANUS AND ANAEROBIC INFECTIONS
PERCUTANEOUS NEEDLE ASPIRATION OF THE LIVER ABSCESS PERCUTANEOUS NEEDLE ASPIRATION OF THE LIVER ABSCESS.
Indications
Liver abscess once diagnosed should initially be treated with drugs, however if no clinical improvement occurs in 48 to 72 hours one should not delay aspirating abscess. All large abscesses (especially those presenting as localised swellings or bulges of the right lower thorax), superficial abscess, abscesses causing severe pain or having marked point tenderness or oedema and abscess with marked elevation of the diaphragm should be aspirated as early as possible.
A clinical picture suggesting an impending perforation and cases with left lobe abscess, where fatal complications of rupture into the pericardial sac or peritoneal cavity can occur at any time are indications for immediate aspirations.
Contraindications
Whenever the diagnosis is in doubt, it is preferable to institute conservative management rather than entering into a hydatid cyst with consequent anaphylactic shock or a haemangioma which may result in internal haemorrhage leading to shock. It is preferable to delay aspiration in uncooperative patients. Aspirations should be avoided in patients with bleeding diorders.
Preparation
Investigations like routine blood count, prothrombin time, bleeding and clotting time, LFTs, blood grouping and cross match. Medical management must be instituted prior to aspiration. Vitamin K must be prescribed in the presence of jaundice or raised prothrombin time.
Procedure
The patient is made to fast for six hours. To counteract vagal shock atropine is injected in a dose of 0.6mg half an hour before procedure. The procedure should be carefully explained to the patient. Intravenous line should be maintained with a wide bore cannula and oxygen should be available.
Ideally the aspiration should be undertaken in the operation theatre or in specially designed minor theatre adjacent to the ultrasonology or invasive radiology department and the attendants should be masked gowned and gloved as for any other surgical procedure. Meticulous attention must be paid to asepsis as secondary bacterial infection may worsen the prognosis of amoebic abscess considerably.
The site of aspiration is next determined by as per following criteria:
- The cavity should be localised under ultrasound guidance and a shorter and a safer route should be looked for.
- Presence of a pointing abscess or a localised bulge of the chest wall.
- The location of the point of tenderness.
- In the absence of a point tenderness the needle may be introduced either in the ninth intercostal space in the mid axillary line or the seventh intercostal space in the mid clavicular line.
- Posterio-anterior or the lateral X-ray chest would often indicate the site of puncture.
Liver scan if available is much useful. Ultrasonography is the most accurate investigation available to guide the needle to the right spot. This investigation also indicates the depth to which the needle is to be introduced. When an abscess is pointing and the overlying skin is taught and thin, the puncture should be made in the surrounding healthy skin to avoid sinus formation and subsequent secondary infection.
The position of the patient is determined by the site chosen for the puncture. If anterior or lateral, the patient lies semi-recumbent leaning against a back rest; if, however the site is posterior, the patient is made to lean forward on a cardiac table. The selected area after being subjected to meticulous surgical toilet is infiltrated with 4 to 5 ml of 2% Xylocaine using a 4 inches 24 G needle. A specially designed ultrasound probe with needle attachment can be used for accurate insertion and prompt drainage of the pus and multiple punctures can be avoided. The infiltration should include the diaphragm and tissues upto the capsule of the liver. Adequate time of about 5minutes should be allowed for the anaesthetic to act.
In a small percentage of cases, the periphery of the abscess is so close to the chest wall, that pus is [bad word] even with the small needle through which the local anaesthetic is given.
A small puncture with stab knife may be made in the skin at the site of needle puncture. This reduces any chance of needle carrying skin bacteria into abscess cavity and permits free movement of the needle inside to aspirate the entire contents completely. Percutaneous aspiration may be done with any large bore cannula (No18) or lumbar puncture needle.
While the needle is being withdrawn or introduced, the patient is asked to take shallow breath throughout the procedure and hold his breath to minimise the liver trauma and haemorrhage. While aspirating every attempt should be made to avoid traversing the pleural or peritoneal cavity.
Once the needle enters the abscess cavity, the pus often gushes out if it is under pressure. A 20 ml syringe is now attached and used to create a negative force which can be regulated according to the resistance to the flow of pus. A bivalve greatly facilitates the procedure. If pus is not encountered even after inserting the needle in two or three directions, the procedure should be abandoned and a re-ultrasound should be done to see if the cavity has drained intraperitoneally. The practice of multiple exploratory thrusts in different directions should be deplored. When an abscess just cannot be located laparotomy is safer. 10 cms is the limit to which the aspirating needle may be inserted so the puncture to the portal radicle can be avoided.
The procedure should be abandoned if the patient seems to be distressed.
Aspiration is continued until no more pus can be evacuated. The last part of the aspirate has a more bloody appearance and at this stage the patient may experience an aching pain in the liver or right shoulder. Occasionally he may even start coughing. The terminal aspirate is rich in trophozoites and therefore should be send immediately for culture and smear in proper sterile containers and either the laboratory should be informed before start of procedure or necessary arrangements should be available at the site of aspiration.
It is usually not possible to evacuate completely as the abscess walls cannot collapse much. However healing occurs in the presence of the residual pus. As this pus is not under pressure, there is no risk of a leak along the aspiration track.
The puncture wound is sealed and covered with dressing. Analgesics should be given to relieve the pain and intravenous antibiotic or amoebicidal should be given as necessary if not given at the start of the procedure. For the first twelve to twenty four hours a half hourly watch is kept on the temperature, pulse, respiration, and abdominal girth so that signs of haemorrhage or peritonitis may not be missed. For the same reason it is preferable to avoid sedation. Once haemorrhage or peritonitis is diagnosed blood transfusion should immediately be started and preparation made for laparotomy. Intracardiac rupture have also been treated by percutaneous method alone 94.
Spinal Needle, ultrasound probe attachment, sterile foil use and aspiration is shown in figures 29 to 32.
Complications
The complications are more commonly encountered as secondary infections and haemorrhage. Anatomical variation may lead to haemorrhage 95.
Aspiration continues as one of the routes by which bacteria can enter amoebic liver abscess and secondarily infect it. (The other routes are haematogenous or after rupture into the lung, viscus, etc.). Secondary bacterial infection is often endogenous in origin occurring after primary aspiration due to disintegration of the lining wall of the cavity, allowing the entrance of portal blood containing organisms from the damaged bowel.
Clinically if the patient remains toxic and the fever does not settle down inspite of vigorous therapy, a secondary infection should be suspected. If aspiration is now repeated the pus is usually found thinner, yellowish in colour and may have an odour. A gram stained slide may demonstrate the organism.
When such complication occurs vigorous treatment with specific antibiotic (dictated by culture and sensitivity test) should be administered in addition to the normal amoebicidal therapy. Aspiration will greatly aid recovery. Most cases will respond to this line of treatment. If the patient shows no improvement or the amount of pus aspirated at each session does not diminish, open drainage may be considered.
Haemorrhage could occur during or after procedure and could be associated with tear of the liver substance. Intrahepatic haematoma peritonitis, pleural effusion, pneumothorax and death due to vagal shock have been described. Amoebic ulcer formation at the site of aspiration have also been reported.
Dry tap
Failure to aspirate pus indicates wrong technique, improper localisation of the abscess or a mistaken diagnosis. On some occasions an abscess may be filled with a solid jelly like substance which will not flow out through even a wide bore cannula. Such lesions are however rare.
Repeated aspirations
The number of aspirations required in any patient is dictated by the clinical response. In general it may be said that if more than 200ml pus is removed, further aspirations in two to three day’s time should be done.
Repeated aspirations is required in any patient with a large abscess in whom the symptom persist or worsen a few days after the primary aspiration. Persistence of X-ray signs after primary evacuation of a sufficient quantity of pus also constitutes an indication for repeating aspiration.
Disadvantages
Thorough surgical drainage is not possible. Surgical treatment is a good alternative in septic patients with severe disease where a delay in adequate drainage, can cause irreversible damage 96.
ROLE OF LAPAROSCOPY
Of all the abdominal viscera the liver lend itself most readily to peritoneoscopic visualisation. More and more diseases of the abdominal cavity are the indications for the laparoscopic intervention to reduce the morbidity and mortality. Laparoscopy is now being used for the management of liver disease 97. Liver abscess is one of them which is potentially fatal if treated improperly and gives excellent results with laparoscopic techniques. Laparoscopic guided trocar insertion can be used for percutaneous introduction of drains into abdomen for draining the abscess perforated intra-abdominally 98. There have been reports of management of complicated multiple abscesses secondary to perforation of gallbladder and spread of the infection into the liver and ultrasound and computerised tomography were inconclusive, and the diagnosis was established by laparoscopy 99. Most of the literature of the on laparoscopic visualisation is from the West.
The following are the main indications of laparoscopy
Patients suspected of amoebic liver abscess and extrahepatic masses could not be excluded with confidence.
A patient with hepatomegaly and atypical symptoms not fitting into the diagnosis of liver abscess.
A negative aspiration in a diagnosed case of liver abscess.
Suspected leak of abscess or haemorrhage after aspiration.
To exclude malignancy.
After creating the pneumoperitoneum the trocar and the telescopes are introduced through the infra umbilical stab incision. By tilting the operation table up or down, right or left lateral the entire surface of the left lobe of the liver and the entire surface of the right lobe of the liver with exception of the posterio-medial surface are visualised.
The superior and the lateral surface abscess could become adherent to the neighbouring parities and the presence of an underlying abscess could be confirmed by endoscopic palpation of the adjacent liver surface for underlying softening with a probe. Under laparoscopic control these abscess can be aspirated by inserting the aspiration needle through the area of adhesions, preventing any peritoneal contamination by leakage of pus.
In the inferior surface abscess the liver surface overlying the abscess could be adherent to omentum in most cases and to transverse colon in others.
OPEN DRAINAGE AND OTHER SURGICAL PROCEDURES
Surgical evacuation provides a means of complete drainage of liver abscess. It provides good exposure of the diseased organ. Only in the events of complications, open drainage and other surgical procedures are indicated. The indication for surgical treatment of the abscess usually reported were patients in septic conditions, underlying intra-abdominal surgical disease and the failure/contraindication of other therapeutic methods. Herman has described the surgical treatment as a good alternative as a first step not only for the treatment of the primary cause of the abscess in patients with severe disease where a delay in adequate drainage, can lead to high morbidity and mortality rates 100.
OPEN DRAINAGE
The role of open surgical drainage is decreased in the past few years due to the use of modern amoebicidal drugs and antibiotics and more and more patients are being treated by conservative therapy.
Indications of open drainage
1. The main indication is failure of response of the of the conservative therapy and needle aspiration.
2. Left lobe abscess may be an indication for open drainage. If after 24-48 hours of medical treatment there is no response laparotomy may be performed. The abscess is aspirated first, the cavity should be explored there after.
3. Presence of more than one abscess is some times considered indication for drainage.
4. Surgical drainage is a definite indication in the cases of burst or leaking liver abscess with peritonitis.
5. Increase in the size of cavity with deteriorating general condition after needle aspiration is another indication of drainage.
6. If the diagnosis is not confirmed.
7. If a co-morbid condition makes the laparotomy necessary.
Anaesthesia
Careful preoperative preparation, control of blood volume and avoidance of anoxia are more important than the choice of anaesthetic agent. General anaesthesia is offered to the patient. Induced by a small dose of I.V. Pentathol. Hypoxia must be avoided using controlled ventilation. The patient is hyperventilated with a mixture of 50% oxygen and 50% nitrous oxide. Relaxation should be maintained during the procedure. However, because of the possible relationship between liver damage and the use of halogenated anaesthetics the use of Halothane or any potentially hepatotoxic drugs should be avoided as far as possible. Multiple liver abscesses with the presence of jaundice or abnormal liver function test increases the risk of complications and anaesthesia should be given carefully in such situation. In toxic patients epidural block is the anaesthesia of choice. Great care must be given in giving anaesthesia to the patients in liver disease as the metabolism of various drugs could be altered, like the metabolism of atracurium is altered 101.
Principles of Surgery
(a) To avoid the contamination of pleural or peritoneal cavities best accomplished by anterior extra peritoneal or posterior retroperitoneal routes.
(b) To evacuate the contents completely and quickly and establish a drain.
(c) To send the material for culture and sensitivity and for the presence of amoeba.
Operative preparations
Patients with abnormal liver functions requires thorough pre-operative management. In addition, in these patients as well as those with normal liver function, ambulation should be continued up to the day of operation. Blood volume deficits should be replaced and the patient should stop smoking as early as possible prior to surgery. In anticipation of possible hepatic insufficiency, chemical or mechanical preperation of bowel should be accomplished in the period before operation. It is also wise to assure the availability of four units of fresh whole blood, fresh frozen plasma and other agents that may prove useful for the management of post operative complications. Appropriate intra-operative monitoring should include arterial and central venous pressure measurement.
Surgical routes to the liver
The evacuation of a large hepatic abscess by surgical measures (Hepatotomy) is done as the method of drainage when all others fail. The median hepatotomy can be easily and safely performed with the knowledge of hepatic anatomy 102. The location of the abscess and direction in which it enlarges most freely determine the route by which it must be evacuated whether subcostally through the abdominal wall. Under no circumstances should a pyogenic hepatic abscess be drained transpleurally because of danger of contaminating the pleural cavity. Contaminating of both the pleural and peritoneal cavities can be avoided by retroperitoneal operations. However, a right subphrenic or a liver abscess on the right dome of the right lobe of the liver causes sufficient elevation of the right leaf of the diaphragm with obliteration of the costophrenic sulcus, to make a direct approach through the bed of the 9th or 10th rib safe. Certainly a direct approach through the diaphragm allows for better drainage than the long route from the subcostal incisions.
PROCEDURE
ANTERIOR APPROACH
Position
The patient should be placed on the operating table with the right side elevated about 30 degrees. Rotation of the shoulder somewhat more than the hips by the use of appropriately pads will facilitate the thoracic extension of incision. The right arm should be placed in a position that will not cause undue pressure or traction. Suspending arm from a soft sling attached to the either screen is satisfactory.
Incision and exposure
The anterior approach is best suited for abscess in the inferior, anteriolateral and superior aspects of the liver. Of several suitable incisions a long right subcostal transverse incision extending across the left rectus muscle and then extended in a T fashion in to the chest through the seventh or eighth right space provides adequate exposure or by an oblique subcostal incision immediately below the costal arch. Continuation of the incision allows exposure of the left lobe.
Details of procedure
Incision is deepened up to the peritoneum which is then separated with finger till the abscess is palpated. This is now opened by plunging the finger through the wall and the pus is carefully evacuated. Closure
The edges of the wall are re-approximated. Preferably two drains are placed in the abscess cavity or near it to facilitate better drainage. One end of a large soft rubber tube or catheter type drain is introduced into the abscess cavity while other is brought out through a separate stab incision situated slightly below the initial incision, other one is placed in a similar way. The incision is closed in layers and firm dressing applied.
POSTERIOR APPROACH
The posterior approach is preferred in abscess situated posteriorly.
Position
The patient should be placed on the operating table in the left lateral position. The right arm should be supported by a pillow placed to in a position that will not cause undue pressure or traction. Pelvis should be supported by a strap across the table. Bridge can be raised over the lumbar area.
Incision and exposure
The incision is made over the twelfth rib which is resected subperiostealy. A transverse incision through the bed of the twelfth rib at the level of the first lumbar vertebra avoids accidental entry into the pleura.
Details of procedure
On reaching the peritoneum it is separated with a finger in the retroperitoneal space until the abscess is felt. The pus is evacuated and a drain is established and closure is done as described earlier.
Thoracic subpleural route.
This is done by subperiosteal excision of one or more of the ribs in mid axillary line, at the level above the diaphragm, but below the line of pleural reflection
Recent advances
After surgical debridement, the abscess cavity can be filled with two pedunculated greater omentum flaps as a direct feeder road of granulocytes to the infectious focus. An average of 48.5 x 109 granulocytes a day harvested from G-CSF-prestimulated donors can be transfused for a total of 8 days without side effects Combination of greater omentum flaps and transfusion of G-CSF-prestimulated granulocytes may be the optimal treatment for pyogenic liver abscesses due to gp91phax-deficient chronic granulomatous disease refractory to conventional therapy 103.
After care
The after care is mainly the same as for needle aspiration and special attention is paid to the care of drainage tube and specific antibiotic therapy. When the drainage from the catheter gradually diminishes, a process that will take two to three weeks on an average, the drain is gradually shortened. It is preferable to do a contrast “cavitogram” X-ray to ensure that the cavity is obliterated from below up, before the drain is finally removed.
LAPAROSCOPIC DRAINAGE:
The mainstay of the management of liver abscesses has been intravenous antibiotics and radiologically guided percutaneous drainage. However, not all abscesses are treated successfully in this way, and some require surgical drainage. Laparoscopic drainage of liver abscesses may be an alternative to open surgical drainage. In combination with systemic antibiotics, is a safe and viable alternative in all patients who require surgical drainage following failed medical or percutaneous treatment, and in those with large abscesses 104.
Complications
The complication include the spread of infection to other areas. Most other complications are those following any other abdominal operation but bleeding from liver is an important complication which is discussed separately.
HEPATIC RESECTION
Hepatic resection is carried out by several surgeons along with saucerisation and debridment of liver tissues but drainage along with the use of antibiotics and amoebicidal drugs decreases the role of extensive hepatic resections. Hpatectomy (Right or Left) is indicated in the management of difficult cases which are in septic condition and having other complications like thrombocytopenia with multiloculation.
SURGICAL TREATMENT OF COMPLICATIONS
Pericardial involvement requires immediate and repeated aspirations. Some times drainage may be necessary.
Laparotomy with meticulous peritoneal toilet may be necessary in cases of peritonitis following a rupture of the abscess
Amoebic cerebral abscess is a fatal complication. It appears to be unresponsive to amoebicidal drugs and is best treated by early aspirations.
Abscess of the liver which rupture spontaneously into the stomach or intestine generally heal rapidly if the patient survives the initial shock because the position of the opening is favourable for cicatrisation. Usually the drainage is adequate and even large abscesses may heal in three to four weeks
Treatment of pleuropulmonary complications.
Pleuritis and sympathetic pleural effusion usually responds rapidly to the systemic drugs. A small effusion is reabsorbed in the course of few days to a week and hence does not need aspiration. In the cases of amoebic empyaema or a massive amoebic pleural effusion, repeated aspirations of as much fluid as possible hastens healing and prevents troublesome sequel. Rarely the pus is so thick that it is difficult to aspirate in such cases there should be no hesitation in institution of open drainage. Moreover if the volume of pus at successive aspirations does not diminish open drainage should be resorted to.
LEFT HEPATIC LOBECTOMY
In the left hepatic lobectomy, the left lobe is freed from the diaphragm by division of the coronary ligament, drawn down into the wound, and rotated outward and to the right, exposing the undersurface of the lobe and the portal fissure. The posteriolateral aspect of the pedicle is brought into view by this maneuver. The left branch of the portal vein is the first structure and is ligated. The left hepatic duct is then ligated and divided, and finally the left branch of the hepatic artery is ligated and divided, after carefully demonstrating the circulation to the right lobe. The lobe quickly demarcates and excision can then follow the less vascular and relatively fibrous plane of cleavage between the lobes. The incision starts at the sagittal fissure and extends along the septum backward and downward until the left hepatic vein is encountered, isolated and ligated. Mattress sutures are used to compress the cut edge of the liver and if possible the falciform ligament is used to cover the raw surface.
RIGHT HEPATIC LOBECTOMY
In the right hepatic lobectomy the dissection is begun at the hilum of the liver by incising the peritoneum over the common duct. The hepatic artery is identified and followed to its bifurcation, care being taken to demonstrate either the regular division of the common hepatic artery or to demonstrate an anomalous vessel arising from the celiac or superior mesenteric artery supplying the remaining left lobe of the liver. The cystic duct is clamped, cut, and ligated and after the right hepatic duct has been isolated it is divided. The right portal vein is then clamped and ligated. The liver is now rotated towards the midline and the peritoneum overlying the vena cava is incised, exposing the hepatic veins as they enter the vena cava. Usually three or more veins are encountered as it one approaches the “attic.” The main right hepatic veins is identified and ligated, care being exercised to avoid wounding these thin walled vessels. In rotating the liver to the right attention must be paid to avoid kinking the vena cava as it passes through the diaphragm, as this will interfere with the filling of the right heart with its concomitant cardiac irregularity and arrest.
After the pedicle has been carefully exposed and ligated and the hepatic vein ligated and divided the right lobe of the liver can be removed with relatively little blood loss. The parenchyma of the liver can be divided by finger fracture or blunt dissection with the handle of the scalpel and the ligature of the larger vessels and the bile duct. However the use of double row of interlocking No 1 chromic catgut on atraumatic liver needles makes for a minimal blood loss during dissection of the liver parenchyma. The raw surface then covered with the falciform ligament or an omental graft or can be sutured against the under surface of the diaphragm. The left lobe of the liver is found to be swollen, with rounded edges since the total portal venous and hepatic arterial supply must find its way through the remaining 20 percent of the liver tissue. This engorgement will frequently compress the hepatic radicals and results in jaundice in the early post operative period, which rapidly clears when the left lobe compensates for the increased blood supply.
The use of cautery, hemostatics, and other foreign materials should have no place in hepatobiliary surgery, since there is a tendency for bleeding to occur as these substances separate. Packing should be used only in an emergency. Once the patient is in good condition, controlled ligation of the supply to the damaged area of the liver should be carried out. Traumatic rupture of the liver if any proportion, is best handled by hepatic lobectomy.
Ligation of the hepatic artery or its branches is dangerous in proportion to the amount of the liver tissue infarcted. If the hepatic artery is ligated closed to the celiac axis, no difficulty will be encountered unless thrombosis distal to the ligature takes place. If one proceeds terminally, the morbidity and mortality increases until the survival becomes possible. Damage to the common hepatic artery requires immediate repair either by suture or transplant, if the patient is to survive. The use of cryotherapy, the actual cautery and electrosurgery have all been tried and abandoned as inadequate in the management of the haemorrhage from the liver, which may be exsanguinating either from oozing from the liver surface or from open vessels. A tourniquet around the hepatic triad can control bleeding but cannot be left in place for any length of time because of the sensitivity of the liver tissue to oxygen deprivation and the rapid appearance of the anaerobic organism in the infarcted tissue. Careful dissection and ligation of the subtending artery is important. In damage to or sacrifice of the hepatic artery, arterialisation of the portal vein has been proposed as a method of salvaging the patient. However transplant or use of vascular prosthesis should be attempted first, and the arterialisation of the portal vein should be used as a last resort.
The operation of controlled hepatic lobectomy can also be used for primary and metastatic tumours of the liver as well as tumours of the gall bladder and the bile duct, provided the lesion in the bile duct is limited to the right or the left hepatic duct. The tumour of the gallbladder tend to metastasise to the lymph node the retroperitoneal region as well as the juxtacardiac nodes near the diaphragm.
BLEEDING IN LIVER SURGERY:
Despite the many advances made in anaesthesia, antibiotic therapy, transfusion and other supportive measures the liver has remained almost immune to the surgical attack until recently. The knowledge of the liver function and the physiological studies done in the animal laboratory have shown that 70 percent of the liver can be resected and because of the liver’s enormous power of regeneration the patient survives.
The liver is a huge vascular sponge processing about 1500 ml of blood per minute. Its substance is friable and the capsule is delicate, making any but the smallest incision dangerous because of severe haemorrhage. Study of the anatomy and the vascular supply has made possible the control of blood flow to the segment to be operated before the incision in the liver is made.
The Couinaud classification divides the liver into 8 independent segments each of which has its own vascular flow, outflow and biliary drainage. Because of this division into self-contained units each can be resected without damaging those remaining. For the liver to remain viable, resections must proceed along the vessels that define the peripheries of these segments. In general, this means resection lines parallel the hepatic veins while preserving the portal veins bile ducts, and hepatic arteries that provide vascular inflow and biliary drainage through the centre of the segment.
DEFINITIVE TREATMENT:
The segmental arrangements of the arterial supply and the portal vein is useful in controlled hepatic lobectomy, but hepatic venous system follows an independent course unrelated to the other vessels, making excision of the larger segmental portions of the liver hazardous. The entire right half of the liver must be considered as a surgical unit to be excised in toto.
Total right or left hepatic lobectomy is an infinitely safe procedure than segmental excision, because blood loss is greatly reduced by the preliminary identification and ligation of the vessels to the lobe. Less than 20 percent of the normal liver tissue is necessary to maintain life and liver has great potential for regeneration
Left hepatic lobectomy and extended right hepatic lobectomy are now practical through control of the hepatic pedicle with ligations of the vessels to the individual lobes. The hepatic blood flow is normally 1500ml per minute. The greater quantity of this blood (80 per cent) comes through the portal vein where the pressure is lowest (8 to 12 mmHg) and oxygen tension is only 50 per cent. The hepatic artery, although delivering less blood has a higher pressure (about 120mmHg) and a very high oxygen tension.
Normally the hepatic artery arises as a single vessel from the celiac axis, dividing into right middle and the left hepatic branch before entering into the liver parenchyma. With in the liver further regular divisions takes place to supply the various segments and lobules in 25 percent of the patients anomalous vessels will be found. It is necessary to carefully dissect and demonstrate arterial blood supply to the remaining portions of the liver before any ligation is carried out.
The portal vein averages about 6.5 cm in length and is regular in its division to the right ant left branch, however is short and embedded in the liver hilum, making ligation difficult and hazardous.
The return of the flow to the caval system is through the hepatic veins. From the surgical stand point the relative inaccessibility and the huge volume of blood they carry (1500 ml per minute) make any accident to these thin walled venous channels result in serious blood loss. The large hepatic veins enter the vena cava in so called “attic” of the liver which can be approached from the above the diaphragm. The left hepatic vein draining the left hepatic lobe and the middle hepatic vein draining the quadrate lobe may enter the vena cava as a single vessel or they may enter as a separate vessels side by side. The possible variation is of importance of lobectomy. The left hepatic vein is joined by superior left hepatic vein before entering the vena cava. From the middle of the caudate lobe the caudate hepatic veins enter the vena cava as a separate vessels. The right lobe of the liver is drained by the right hepatic vein and the right dorsal hepatic vein. The dorsal hepatic veins drains the dorsal surface of the liver, and the interior dorsal hepatic vein drains the zone lying between the right margin of the gall bladder.
POST OPERATIVE INVESTIGATIONS TO MONITOR LIVER FUNCTION
Studies have suggested that changes in liver function tests may vary with the postoperative time interval and may be related to the extent of hepatic damage. Routine postoperative management in lobectomy patients included assessment of liver function tests and enzymes daily for the first week, then at approximately 2 and 4 weeks postoperatively. These tests included: prothrombin time (PT), partial thromboplastin time, total serum bilirubin, total protein (TP), aspartate transaminase, lactate dehydrogenase (LDH), alkaline phosphatase, albumin (A), and glucose. Patients undergoing wedge resections had these values checked less frequently, approximately 3 to 5 days, 2 weeks, and 4 weeks postoperatively. Patients undergoing major hepatic resection have characteristic postoperative profiles of liver enzymes and liver function tests. The profiles reflect changes in volume status, parenchymal liver destruction, transient hepatic insufficiency, and postoperative hepatic regeneration. However, except possibly for PT and bilirubin, the routine use of these tests is not recommended, given that the results do not alter clinical management 105.
Washington, DC Registry
Last modified: Monday, 29-Nov-2004 07:08:32 EST |
