The purse-string suture in nephron-sparing surgery for renal cell carcinoma

Authors


L. Safarik, Charles University Prague, Urology, Prague 2, Czech Republic.
e-mail: lsafarik@hotmail.com

INDICATIONS

Nephron-sparing surgery has gained popularity in surgery for RCC, since Novick and others reported its efficacy for tumour control, long-term survival and outstanding functional results [1–4]. Previously, resections were accomplished only in those with a solitary kidney or with several kidney impairments and synchronous tumour masses. Currently, nephron-sparing surgery was extended to cases where tumours are < 4 cm in diameter and confined to one or both kidneys, usually avoiding the mesorenal region (Fig. 1). There has been always dispute over the consequences and duration of renal warm and cold ischaemia. Temporary clamping of the renal pedicle is recognized as the mainstay of blood control (with or with no ice-slush cooling). A purse-string suture (single or double) can successfully replace pedicle clamping in many cases and spare the kidney even the briefest ischaemia. Blood loss control is excellent, before and after surgery, and for closing the defect bridging sutures are secured in situ on the reinforced cavity edges, through the purse-string suture. Since 1997 we have treated 17 patients with this technique, with no complications, giving excellent disease control and functional outcome of the kidney.

Figure 1.

A left-sided RCC tumour, 40 × 30 × 20 mm.

METHODS

In all, 29 patients were treated for RCC with the purse-string technique (17) or with the standard resection (12) over the past 4 years. Through an intercostal incision the retroperitoneal space is developed and the kidney exposed through Gerota's fascia [5]. The fatty tissue is left only on the tumour protrusion, but the surrounding kidney is cleared of all fat. The kidneys are not cooled. The renal hilus is left intact, with no dissection around it. A thick suture of braided absorbable material, e.g. no. 1 polyglactin, is placed 8–10 mm from the outer margin of the tumour (Fig. 2a,b) including extensive ’bites’ into the parenchyma. It is important to use the semicircular round-bodied needle (no. 30) or a little larger, and it is probably better to have two sutures placed next to each other (double string) so that when one thread exits the tissue the complementary one meets it, and vice versa. Before tying, both ties should form an uninterrupted intermingling circle around the tumour margin. The suture ends are tied, making the tumour slightly raised above the surrounding kidney surface and more ischaemic by compression of adjacent renal tissue. Then a harmonic scalpel is used (or monopolar diathermy) to excise the tumour with a 5-mm margin circumferentially. It is important to work slowly to enable the harmonic scalpel to seal all the bleeding vessels. If a major vessel is opened bipolar forceps are used to close it satisfactorily. Lateral compression from the purse-string suture holds the major arteries and leaves only minor oozing from the sites of the cavity in most cases. The most annoying bleeding comes from a few arteries at the bottom of the cavity, where the compression from lateral ties is absent, but these sources are quickly controlled with either bipolar diathermy or one suture of 3–0 polyglactin. When the tumour is excised and a basal biopsy taken, the bridging sutures (No. 1) are anchored just behind the tied purse string(s) threads on opposite sides of the renal cavity. Polyglycolic acid mesh (Surgicel(r), Johnson & Johnson, USA) is laid into the cavity and bridging interrupted sutures tied over it. Inserting bridging sutures behind the circular suture on both sides has the advantage of reinforcing the fragile renal tissue and hence the sutures can be tied with no renal tearing (Fig. 2c). When finished the haemostasis is excellent. A Penrose drain is placed next to the sutured kidney and Gerota's fascia and upper layers closed appropriately.

Figure 2.

Figure 2.

(a,b,c) The scheme of the double purse-string suture tied around the tumour, and in vivo after the tumour was removed with no pedicle clamping, and re-approximating sutures put across the tied purse-string suture.

Figure 2.

Figure 2.

(a,b,c) The scheme of the double purse-string suture tied around the tumour, and in vivo after the tumour was removed with no pedicle clamping, and re-approximating sutures put across the tied purse-string suture.

Figure 2.

Figure 2.

(a,b,c) The scheme of the double purse-string suture tied around the tumour, and in vivo after the tumour was removed with no pedicle clamping, and re-approximating sutures put across the tied purse-string suture.

Both the ’purse-string’ and ’control’ patients were treated during the development of improvements in the technique of kidney resection so initially more patients had the classical resection approach, but in last 2.5 years only the purse-string method was used whenever appropriate, because it is simpler and causes less blood loss.

Blood loss during the surgery was estimated by weighing the sponge pads and gauze (which absorb ≈ 20 mL) and blood from the aspiration. The output from the Penrose drain was measured and added to the total blood loss from surgery. An unpaired t-test was used to compare the two groups.

The surgery was undertaken by four urological surgeons, including two residents in-training, in the 29 patients. To compare the blood loss with the standard technique, 12 consecutive patients were operated with a tourniquet or a clamped renal pedicle and separate ligation of the bleeding vessels with 3–0 polyglactin. Surgicel mesh was used in both groups to help haemostasis after tumour excision. The harmonic scalpel was used in all, so that the only variable was the purse-string modification around the tumour. The mean duration of surgery was similar (116 vs 123 min), and the total blood loss (before and after surgery) was 194 mL for the purse-string and 354 mL for the standard method (P < 0.001; Table 1). The patients were mobilized 3 days after surgery. A blood transfusion was required once in the purse-string group and five times in the other group; the only case in the former was when the purse-strings were cut accidentally with the harmonic scalpel during resection. The sudden blood loss was 1450 mL in the aspirant and the renal pedicle was compressed manually until another double purse-string was placed and tied to control the bleeding (blood loss in this case was estimated separately before, during and after the accident). The final results, both morphological and functional, are shown in Fig. 3a,b as an example. A DMSA scan was taken 1 year after resection of the largest (4 cm) tumour; the proportion of functioning renal tissue was 60:40 in favour of the unresected kidney. This was the largest tumour resected with the new technique and we consider the tracer deficit was probably a result of the malignant renal tissue removed rather than ischaemia after surgery, which should be minimal with this technique.

Table 1.  The tumour diameter, position and blood loss in both groups of patients
PatientPurse-stringStandard
Tumour, mmLoss, mLTumour, mmLoss, mL
  1. LP, lower pole; M, mid part; UP, upper pole.

 121 LP 14525 M320
 226 LP 16927 LP387
 339 LP  21116 M412
 429 M 25336 LP390
 538 LP 24039 LP245
 637 LP 16328 M368
 726 M 17838 LP302
 828 UP 23637 LP248
 926 M 21035 LP390
1034 M214026 M368
1140 LP240130 LP420
1233 LP264234 LP400
1327 M 147  
1426 M 138  
1522 LP 174  
1637 LP 164  
1734 LP 155  
Mean30.76 194.230.9354.2
Figure 3.

Figure 3.

(a,b) A CT and DMSA scan of the same patient, taken 1 year after the previous removal of a 40 mm tumour.

Figure 3.

Figure 3.

(a,b) A CT and DMSA scan of the same patient, taken 1 year after the previous removal of a 40 mm tumour.

COMPARISON WITH OTHER METHODS

Nephron-sparing surgery is a vital technique which has been confirmed to have the advantage of leaving as much functioning renal parenchyma as possible and to maximize the possibility of a clear oncological margin [6,7]. The oncological perspective is important, as patients after kidney resection for a malignancy have a 75–95% 5-year cancer-specific survival, and the risk of recurrence is 6–10%[8]. Thus preserving the renal parenchyma is important, particularly in younger individuals, whose life expectancy is likely to be decades. Resection techniques have developed steadily, using different technological advances (lasers, water-jets, etc.), but all rely more or less on some type of pedicle clamping, and sometimes on other types of renal hypoperfusion for the kidney (cooling) [9]. Using the double purse-string suture around the tumour before resection considerably reduces the blood loss during resection and avoids the need for renal hilar compression with a clamp or fingers, at least temporarily. Dissecting around the renal hilus and subsequent hilar clamping almost inevitably causes partial renal ischaemia with subsequent adverse effects on the kidney's blood supply. Leaving the renal pedicle intact during resection does not compromise this sensitive area, and any possible subsequent nephrectomy for future recurrences or other renal illness is much easier than after previous dissection and healing around the hilus. If a subsequent resection is attempted for recurrent or metachronous tumour, the perirenal and perivascular adhesions would possibly be less pronounced than after complete dissection and routine pedicle control with a clamp. Particularly patients with multiple renal tumours (von Hippel-Lindau disease) might benefit from this new technique. The importance of an appropriately placed purse-string suture(s) was evident in the one case where the suture was cut and the sudden blood loss was 1450 mL. Some authors do not consider the harmonic scalpel to be as efficient in controlling bleeding, but our experience with purse-strings combined with the harmonic scalpel was satisfactory [10]. During the procedure the kidney does not need to be so extensively exposed, as recently reported with the use of a DeBakey aortic clamp [11]. The favourable low blood loss during and after surgery was mostly attributed to the sustained and more durable blood vessel control in the renal cavity by the purse-string, as it was the only major difference in the management of the present patients. The purse-string seems to prevent bridging sutures from tearing through during tying, and thus becoming loose in the fragile renal tissue after surgery. Hence patients can be safely mobilized 3 days after surgery, with no haematoma apparent on ultrasonography. To date we have detected no recognisable haematoma when the patients were discharged from hospital (at 7–10 days). The lower uptake of radioactive tracer after surgery could be ascribed to the resected tissue rather than ischaemia, as the tracer was dispersed evenly with a similar intensity to that on the other side.

ACKNOWLEDGEMENTS

Supported by grant MSMT J 13/98111100005

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