Limitations of minimal access surgery

To perform minimal access surgery with safety, the surgeon must operate remote from the surgical field using an imaging system which provides a two-dimensional representation of the operative site. The endoscope offers a whole new anatomical landscape which the surgeon must learn to navigate without the usual cues which make it easy to judge depth. The instruments are longer and sometimes more complex to use than those common in open surgery. The result of all this is that the beginner in minimal access surgery is faced with significant problems of hand—eye co-ordination. Stereoscopic imaging for laparoscopy is still in its infancy. Future improvements in these systems will greatly enhance manipulative ability in critical procedures such as knot tying and dissection of closely underlying tissues. There are, however, some drawbacks, such as reduced display brightness and interference with normal vision due to the need to wear specially designed glasses. It is probable that brighter projection displays will be developed, at increased cost. However, the need to wear glasses will not be easily overcome. Looking further to the future, it is evident that the continuing reduction in costs of elaborate image processing techniques will make a wide range of transformed presentations available. It will ultimately be possible for a surgeon to call up any view of the operative region that is accessible to a camera and present it stereoscopically in any size or orientation, superimposed on past images taken in other modalities. It is for the medical community to decide which of these many imaginative possibilities will contribute most to effective surgical procedures.

Another problem occurs when there is intraoperative arterial bleeding. Haemostasis may be very difficult to achieve endoscopically because blood obscures the field of vision and there is a significant reduction of the image quality owing to light absorption.

Some of the procedures performed by this new approach are more technically demanding and are slower to perform. Indeed, on occasion a minimally invasive operation is so technically demanding that both patient and surgeon are better served by conversion to an open procedure. Unfortunately, there seems to be a sense of embarrassment or humiliation associated with conversion which is quite unjustified. It is vital for surgeons and patients to appreciate that the decision to close or convert to an open operation is not a complication but instead usually implies sound surgical judgement.

Another disadvantage of laparoscopic surgery is the loss of tactile feedback. Laparoscopic ultrasonography might be a substitute for the need ‘to feel’ in intraoperative decision making. Although ultrasonography has progressed significantly in the past several years, laparoscopic ultrasound remains in its infancy. The rapid progress in advanced laparoscopic techniques, including biliary tract exploration and surgery for malignancies, has provided a strong impetus for the development of laparoscopic ultrasound. Although in­completely developed, this technique already has advantages that far outweigh its disadvantages.

In more advanced techniques the large piece of resected tissue, such as the lung or colon, has to be extracted from the body cavity. Occasionally, the extirpated tissue may be removed through a nearby natural orifice, such as the rectum or the mouth. At other times a novel route may be employed. For instance, a benign colonic specimen may be extracted through an incision in the vault of the vagina. Although tissue ‘morcellators, mincers and liquidisers’ could be used in some circumstances, this has the disadvantage of reducing the amount of information available to the pathologist. Recent reports of tumour implantation in the sites of port holes have raised important questions about the future of the laparoscopic treatment of malignancy.

Hand-assisted laparoscopic surgery is a newly developed technique. It involves the intra-abdominal placement of a hand or forearm through a minilaparotomy incision whilst pneumoperitoneum is maintained. In this way the surgeon s hand can be used as in an open procedure. It can be used to palpate organs or tumours, to reflect organs atraumatically, to retract structures, to identify vessels, to dissect bluntly along a tissue plane and to provide finger pressure to bleeding points while proximal control is achieved. In addition, several reports have suggested that this approach is more economical than a totally laparoscopic approach, reducing both the number of laparoscopic ports and the number of instruments required. Some advocates of the technique claim that it is also easier to learn and perform than totally laparoscopic approaches, and that there may be increased patient safety.

There is a growing need for improvement in dissection techniques in laparoscopic surgery and, specifically, for improving the safe use of electrosurgery and lasers. Ultrasonic dissection and tissue removal has been utilised by a growing number of specialities for several years. The adaptation of the technology to laparoscopic surgery grew out of the search for alternative, possibly safer, methods of dissection. The current units combine the functions of three or four separate instruments, reducing the need for instrument exchanges during a procedure. This flexibility, combined with the ability to provide a clean, smoke-free field, improves safety while shortening operating times.

Although dramatic cost savings are possible with laparo­scopic cholecystectomy, the position is less clear cut with other procedures. There is another factor which may com­plicate the computation of cost benefit. A significant rise in the rate of cholecystectomy followed the introduction of the laparoscopic approach as the threshold for referring patients for surgery lowered. The increase in the number of procedures performed has led to an overall increase in the cost of treating symptomatic gallstones.