Is Laparoscopic Partial Nephrectomythe 'Gold Standard' for Small Renal Masses?

Laparoscopic Partial Nephrectomy (LPN) is an evolving treatment for the management of small renal cell carcinomas (RCC). Whilst open partial nephrectomy remains the mainstay of nephron sparing surgery, LPN is increasingly considered an alternative therapy in the hands of experienced laparoscopists in high-volume centres. However it remains one of the most challenging urological operations.

Whilst RCC represents a relatively uncommon malignancy, the steadily increasing incidence of this heterogeneous tumour warrants exploration of new methods and techniques in its management. The earlier detection of pre-symptomatic lesions, contributed to in part by an increase in ultrasound and cross-sectional imaging utilisation, corroborates this argument.

Indications

The indications for LPN follow the rationale of general indications for nephron-sparing surgery. An 'elective' case is justified by small renal tumours (T1a) in a position amenable to the technique. 'Relative' indications are those that suggest that the contralateral renal unit is at future risk, such as hereditary cancers, diabetes, hypertension, stone disease and renal impairment. Alternatively, 'absolute' indications are those where the contralateral unit is already affected, such as single functioning kidney, absent kidney or bilateral tumours.

The procedure

LPN may be performed by either an extraperitoneal or a transperitoneal approach, dependent on experience of the surgeon and the anatomy of the tumour. Generally an extraperitoneal approach is favoured for access to posterior and particularly postero- medial tumours. Transperitoneal approach allows for a wider working area and superior angulation of instruments to facilitate reconstruction of the kidney 1.

Whichever approach is used, the overall principles remain the same. Pre-operative imaging should be studied carefully, and 3- dimensional and 2-dimensional reconstructions of cross sectional imaging may provide important useful additional information. Good exposure of the kidney and tumour is paramount. Various mechanisms of achieving vascular control have been explored. Some units prefer temporary cross-clamping of the renal artery and vein as one. In our particular institution we prefer to isolate and clamp the renal artery alone. On-table radiological assistance is utilised in some centres where this expertise exists, whereby tumour position and size is confirmed by intra-operative laparoscopic ultrasound. Much debate exists as to the potentially deleterious affect on renal function by clamping of the hilar vessels, and in order to keep the dysfunction to a minimum the time is limited to 30 minutes, generally. This may be minimised by adequate exposure and meticulous operative preparation, focusing on both equipment and personnel. Various cooling mechanisms have been utilised, but most are difficult to execute effectively when performed laparoscopically, although new methods are currently being researched.

Excision of the tumour is performed with scissors or alternatively harmonic scalpel, and it is of course paramount to achieve adequate surgical and pathological clearance. To this end the oncological outcome of the procedure should always remain the main focus of the surgeon, given the good outcomes presented by the alternative modality of open surgery. Again, where available frozen- section intra-operative analysis may be of use.

Closure of the collecting system should be performed with absorbable sutures, and using a ureteric catheter and retrograde injection of methylene blue dye may facilitate this. Parenchymal closure is not particularly necessary, and commonly a 'buttress' technique is used, using collagen matrix and tissue glue, supported by interrupted sutures. A drain is placed postoperatively, and the patient is closely monitored for signs of complications, such as haemorrhage or urinary leak.

Outcomes of surgery

One of the largest comparative studies by Gill et al. provides us with the broadest insight into LPN. In comparing 1800 patients who had undergone either LPN or open surgery, LPN offered the advantages of reduced operating time, reduced blood loss and shorter hospital stay. LPN was however associated with additional postoperative morbidity, which was mainly urological in origin2. Their 3-year cancer outcomes were essentially equivalent when comparing the two groups. One must bear in mind that these data have been provided to us by perhaps the most prolific laparoscopic urology center in the world. Although LPN is a novel technique that provides the potential advantages of minimally invasive surgery, recent concerns have arisen. A large study from the Cleveland Clinic has suggested that the increased warm ischaemia time associated with LPN may be responsible for the increased requirement for renal support and dialysis in patients with solitary kidneys, and may be associated with higher complication rates3 . In terms of cost effectiveness, it has been shown that LPN is of approximately equivalent cost to open procedures. The shorter length of stay is thought to make up for the higher equipment costs4.

Future developments

Various developments have been introduced to improve the procedure, and many have focussed on ways of reducing warm isch- Is Laparoscopic Partial Nephrectomy the 'Gold Standard' for Small Renal Masses? John Bycroft, Faiz Mumtaz 2008-aemia time or implementing methods of cooling. A recent study has suggested that the need for a 'bolster' may be obviated in selected central renal tumours 5. Exciting developments involving novel cooling techniques may soon be clinically available pending adequate 'wet lab' investigations 6.

Recent studies have suggested that robotic partial nephrectomy is a safe and feasible option for patients with complex renal tumours, for example multiple lesions, endophytic and hilar lesions 7. Whether LPN follows the 'robotic' pathway of procedures such as radical prostatectomy is yet to be seen.

Although it is important to consider other minimally invasive options, such a Radiofrequency Ablation and Cryotherapy, most would classify these procedures as being in their infancy.

Summary

Laparoscopic partial nephrectomy is one of the most demanding procedures performed by minimally invasive urological surgeons. It should only be performed by those who are sufficiently trained in laparoscopy. It may offer several advantages to patient and surgeon alike. The procedure should be carefully audited in order to confirm the longterm oncological outcomes.

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