Besides aspiration (described in the previous chapter), surgical intervention is needed very rarely. Only in the event of complications, open drainage and other surgical procedures may be indicated.

1. Open drainage
Enthusiastic use of surgical incision and drainage of amoebic liver abscess at the turn of the century accounted for the then high mortality rate. Surgeon Valdesstaunch exponent of ¹ was a this method. Similarly Schapirois a must and that ² was convinced that early open drainage there are no additional hazards if necessary precautions are taken.
With the development of powerful amoebicides, open drainage fell into disrepute. In 1923, Manson-Bahr strongly condemned this procedure with its risks of secondary infection resulting in sinuses, peritonitis and other unpleasant sequelae.
However, the alarmingly high mortality of the past has recently come down dramatically, probably due to the availability of modern drugs, anaesthesia and surgical procedures. Table I shows fall in mortality rate from 14% in the late sixties to 8% in the early seventies.³

TABLE - I

The total number of patients requiring surgery has been decreasing as most of them are treated successfully by conservative therapy.

Indications
Today, the most important indication for open drainage of an amoebic liver abscess is secondary infection, which fails to respond to appropriate antibiotics in addition to amoebicidal therapy and aspiration.
A left lobe abscess may also 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. It should then be entered and dependent penrose drain established.⁴ (Currently, in centres with scanning facilities, most of these patients are being aspirated percutaneously with success.)
Presence of more than one abscess is considered by some authors to be an indication. We have had to resort to it rarely and only when tapping did not yield enough pus.
Surgical drainage as discussed elsewhere has to be undertaken in cases of rupture with peritonitis.
In the present era of specific amoebicides, previous indications like failure to evacuate pus by aspiration, necessity for repeated aspirations and minimal clinical improvement⁵ no longer warrant surgical intervention. However, after three to four aspirations if the quantity of pus which can be removed does not decrease, open drainage is indicated.

Procedure
The patient is prepared as in any other abdominal operation.

Anaesthesia
General anaesthesia is induced by a small dose (not more than 200 mgm.) of 1. V. Pentothal. Injection of scoline is given 1. V. in a dose of not more than 50 to 75 mgm. Hypoxia must be avoided by using controlled respiration. The patient is hyperventilated with a mixture of 50% oxygen and 50% nitrous oxide. For maintaining relaxation, Flaxedil should be used. The use of Tubarine and Halothane should be avoided as far as possible. In patients having multiple liver abscesses, jaundice or abnormal liver function tests, Scoline should be avoided. In toxic patients (and many cases coming to surgery are toxic) epidural block is the anaesthesia of choice.

The principles of the operation are:

1. To avoid contamination of pleural or peritoneal cavities best accomplished by anterior extraperitoneal or posterior retroperitoneal routes,
2. to evacuate the contents quickly and completely and to establish a drain,
3. to send the material for culture and sensitivity tests and institute specific antibiotic therapy.

The anterior approach is best suited for abscesses in the inferior, antero-lateral and superior aspects of the liver. A subcostal transverse incision is made and deepened upto the peritoneum which is then separated with a finger till the abscess is palpated. This is now opened by plunging the finger through the wall and the pus is carefully evacuated. One end of a large soft rubber tube is introduced into the abscess cavity while the other is brought out through a separate stab incision situated slightly below the initial incision.^6-8 The incision is sutured and a firm dressing applied.
The posterior approach is preferred in abscesses situated posteriorly. The incision is made over the twelfth rib which is resected subperiostealy. A transverse incision through the bed of this rib at the level of the first lumbar vertebra avoids accidental entry into the pleura. 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 established as described earlier.
The after care is the same as described in the previous chapter and special attention is paid to the care of the drainage tube and specific antibiotic therapy. When the drainage from the catheter gradually diminishes, a process requiring two to three weeks on an average, the drain is gradually shortened.³ 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.
The most important complication of open drainage is secondary infection, the onset of which is heralded by increasing pain, rising fever, leucocytosis and a change in the character of the drainage fluid. It has been discussed in detail earlier. After culture and sensitivity tests, the specific antibiotics should immediately be started. Most other complications are those following any abdominal operation and are best dealt with in any text book of surgery. Others like skin amoebiasis have already been discussed.

2. Hepatic Resection
Balasegaram⁹ carried out hepatic resection in seven of his cases. He also did saucerization with debridement of liver tissue in some cases.
With the availability of modern amoebicidal drugs and antibiotics, hepatic resection would be considered obsolete by many authorities.

3. Surgical Treatment of Complications
Pericardial involvement requires immediate and repeated aspirations. Sometimes drainage may be necessary.¹⁰ The subject has also been dealt with in chapter on Amoebic pericarditis.
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 aspiration.¹¹
Abscesses 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 cicatrization. Usually the drainage is adequate and even large abscesses may heal in three to four weeks.¹²
The treatment of pleuropulmonary complications is discussed in the next chapter.

References

1. Valdes, U. Surg. Gyn. Obst. (I.A.S ),1926, 42, 822.
2. Schapiro, M M, Arch. Surg., 1956, 73, 780.
3. Bautista O'Farrill, I, Proc. Internat. Conf. on Amoebiasis, 1975, Ed. by Sepulveda B. and Diamond, L S. Instituto Mexicano Del Seguro Social; Mexico, 1976.
4. Bockus, H L, Gastroenterology, Vol IV, 3rd Edition, W B Saunders & Co., Philad.. 1976.
5. Wilmot, A J, Clinical Amoebiasis, Blackwell Scientific Publications, Oxford, 1962.
6. Davis L, Christopher's Textbook of Surgery, 11th Edition, W B Saunders & Co., Igakussion Asianed, Tokyo, 1977.
7. Schwartz, S L, Principhs of Surgery, Vol. II, 2nd Edition, McGraw-Hill Book Co., New York, 1974.
8. Ochsner, A, Maingot's Abdominal Operations, Vol 1. 5th Edition. Appleton Centurv Crofts. Publishing Division Prentice Incorporation, New York, 1974,
9. Balasegaram, M, Ann. Surg., 1972,175, 528.
10. Lamont, N M, and Pooler, N R. Quart. J. Med., 1958, 27, 389.
11. Huges, F B. J. Pediatrics, 1975, 86, 95.
12. Paul Milroy, Brit. J. Surg, 1960, 47, 502.