The art of open stone surgery for huge complete complex stag horn renal stone: Anatrophic Nephrolithotomy “

These days, renal stones can be treated with non-invasive procedure like Extra-corporeal Shock Wave Lithotripsy (ESWL) and minimally-invasive procedure like Percutaneous Nephrolithotripsy (PCNL). However, huge complete complex stag horn stones remain a challenge because it is difficult to have complete stone clearance with these treatment modalities in a single setting. Additional or auxiliary procedures are usually required for stone clearance which lead to higher costs and burden for the patients.

Staghorn Calculi

Staghorn stone are large renal calculi that occupy most or all of the renal collecting systems. The name arises from the fact that these stones look like the antlers of a deer or stag on imaging.

Anthropology history provides evidence suggesting that urinary stones existed as long as 7000 years ago and perhaps longer. (Clendening, L., 1942)
Untreated, staghorn stones are associated with recurrent UTIs, urosepsis events, renal function deterioration and a higher likelihood of death. Complete renal function loss in 50% of affected kidneys can occur after 2 years without treatment. (Blandy and Singh, 1976; Koga et al., 1991; Segura et al., 1994; Teichman et al., 1995)

Various Options of Treatment of Huge Complex Complete Staghorn Stones :

If PCNL alone is chosen for these stones, multiple access is unavoidable and that can cause more bleeding necessitating blood transfusions. On top of that, cost-effectiveness is a priority in our clinical scenario and majority of the hospitals and patients cannot afford multiple treatment modalities.
We have tried laparoscopic surgery on stag horn stones. We found out that partial staghorn stones are suitable for it but complex complete stag horn stones demand longer operation time hampering renal function.
Thus open surgery, Anatrophic Nephrolithotomy is the most appropriate procedure for these cases in our country at this time.

The Art of Open Stone Surgery:

This article is aimed to provide tips and tricks and highlight some of the important steps to avoid mishaps in surgical procedure for huge complex complete stag horn renal stones.

Preoperative antibiotics as dictated by urine C&S need to be given at the time of induction. Procedure is usually done under general anesthesia and patient in the kidney position, flexed to widen the area between costal margin and iliac crest. The incision is usually supra 12.

The incision can be extended laterally about 1 to 2cm from the tip of 12th rib. By reflecting the diaphragm from posterior aspect of 12th rib with the finger internally, we can prevent accidental opening of the pleura. In obese patients, through 12 incisions is used.
When the lower pole of the kidney is mobilised, if there is dense fibrosis, IVC can be very close and stuck to it. Thus proper care is essential not to tear it accidentally. In upper pole dissection, care must be taken not to injure Upper pole artery and adrenal gland.
Then, mobilised kidney is raised up by a sling and the renal artery is identified. The renal artery can be branched early when arising from the aorta and both posterior and anterior branches need to be identified. Polar artery and lower pole aberrant artery should not be missed if present. Tactile sensation is useful. The key to success of further steps depend on identification of all arteries supplying the kidney and control them. After identifying all arteries, they are slinged.
Our practice is using normal saline ice sludge to cool down the kidney for 10 minutes. Ten minutes immersion can cool down the core temperature of the kidney to 15 degree centigrade and that state allows 30 minutes of warm ischemia time without impairing renal function.
After that, the main renal artery or all arterial branches are temporarily clamped with bull-dog clamps. The incision is made along the Brodel’s line and that is the area between anterior and posterior segmental arteries .All the stones are easily identified and removed. 
Those hidden in calyces can be detected by ultrasound and fluoroscopy.
This is a solitary kidney with staghorn stones with sepsis. Procedure was as before. When all stones are removed, infundibuloplasty (Calycorrhaphy) (Figure 2) is done in to make the whole calyceal complex into one broad system. Infundibuloplasty is approximating adjacent calyceal walls as shown. The suture is 30 vicryl. Now all the calyceal systems become one big system. That will minimize stasis and the chance for recurrent stone formation is reduced. After that, double J stent is inserted. (Figure3)
Now, the opened up kidney is to be closed back. The inner layer is approximated by vicryl 30 with round needle in continuous fashion. The bites should not be deep in parenchyma tissue. All calyceal system needs to be closed in inner layer. The outer layer that is cortical border is closed with chromic 20 or vicryl 20, round needle 40 mm in vertical mattress fashion. (Figure4).

The bites should not be deep.
The whole process must be finished in twenty to thirty minutes. Then, the arterial clamps are removed and check oozing or bleeding from incision or bleeding from the calyces flowing down to pelvis and ureter.
Some oozing from the incision line can be stopped by the compression with the swab for a few minutes. If there is persistent oozing, a new bite with Chromic or vicryl 20 on that site after test pressing will stop the bleeding.
Post-operative KUB is taken on 4th day and discharge on 5th to 7th day. In our 18 year study, Stone Free Rate (SFR) is 94.6%. The SFR of initial four years is less than the later part of the study.
Due to the concern of renal function after surgery, a post operative functional study was done at one month.
If the case had previous surgery with dense fibrosis, approach hilum through virgin area.
If pleura is opened up accidentally, if noticed in intra operative period, put purse string absorbable suture around tear, put one end of infusion set into pleural cavity and another end inside the kidney dish with water, creating an underwater seal tube. Then the Anaesthetist should inflate fully, purse string is tightened and knot the suture.
If the hilum has dense fibrosis and impossible to identify artery and vein seperately, use Satinsky clamp to clamp all together.
If IVC is accidentally torn, use satinsky and 4 0 proline.
Malleable brain retractor are useful to retract the opened up kidney to get proper exposure of calyceal system in performing infundibuloplasty.

Discussion:

Despite the availability of non-invasive and minimally invasive procedures, open stone surgery , in the form of Anatrophic Nephrolithotomy remains an appropriate procedure for huge complex complete stag horn renal stone at this time in our clinical settings.
Master of Medical Science MMedSc (Urology) program was started in 2016 according to the curriculum created after working together with the Royal College of Surgeons, Edinburgh.
The first batch of 23 urologists was produced at the end of 2018. They will be further trained for 2 years at the Departments of Urology of our Universities. After that some will be serving as independent urologists at remote state and divisional hospitals. The people living in remote areas tend to have large stones compared to those living in urban areas as the disease is usually found at the advanced stage.
This paper is particularly aimed for those upcoming urologists to be produced every year from now on and the senior consultant surgeons who are working at the state and divisional hospitals and already having independent surgical experience of more than 5 years.

Conclusion:
In the past, in state and divisional hospitals , when such complex cases are encountered, they could end up with nephrectomy.
Our aim of surgical treatment is successful removal of large complex complete stag horn stones completely with conservation of the affected kidney.

Toe Lwin FRCS FACS Dr.Med.Sc
Hon. Professor 
Department of Urology
University of Medicine 1 Yangon