Postureteroscopic Lesion Scale: A New Management Modified Organ Injury Scale

Abstract

Background and Purpose:

Objective parameters for the classification of ureteral injuries and resulting indications for ureteral stent placement after ureteroscopy are lacking. We hereby present a new classification system including proof of interrater reliability and validation of recommendations for postoperative ureteral stent placement.

Patients and Methods:

The Postureteroscopic Lesion Scale (PULS) was applied in 435 patients undergoing ureteroscopy. Interrater reliability between three surgeons (junior resident, senior resident, and specialist) was evaluated in 112 patients. Postoperative ureteral stent placement was performed according to PULS. For follow-up with ultrasonography, we assumed hydronephrosis to be an indirect sign for significant postoperative ureteral obstruction.

Results:

No ureteral lesion was seen in 46.2% of patients (grade 0). A grade 1, 2, or 3 lesion was seen in 30.8%, 19.1%, and 3.9% of patients, respectively. No grade 4 or 5 lesions were observed in our series. Interrater reliability was high (Kendall W=0.91; mean Spearman Rho=0.86). This was particularly true between senior resident and specialist (Rho=0.95), compared with junior resident and senior resident or specialist (Rho=0.83, Rho=0.79, respectively). All patients with documented lesions had a Double-J stent placed. Indwelling time varied according to PULS. Results of a postoperative ultrasonographic follow-up could be obtained in 95.6% of cases. No patient showed clinical or sonographic signs of upper urinary tract obstruction.

Conclusions:

According to these preliminary data for the clinical application of PULS, interrater reliability is high. Standardized empiric recommendations for the use and duration of postoperative stent placement after ureteroscopy might be useful in guiding urologists in this conversely discussed issue, ultimately preventing ureteral strictures as a late complication of ureteroscopy. These will have to be confirmed, however, by controlled trials in the future.

Introduction

S emirigid and flexible ureterorenoscopy (URS, f-URS) have become increasingly popular for the treatment of patients with urolithiasis and other pathologies of the upper urinary tract. Different access techniques have been proposed; eg, the use of an access sheath compared with “wireless and sheathless.”¹ Stone-free rates, effective tumor ablation, and complication rates have significantly improved during the last decade. Stone-free rates of up to 99% and complication rates ranging between 9% and 11% overall, with ureteral perforation accounting for 1% to 4%, have been reported.^2

–6

Postendoscopic ureteral stent placement, however, remains a subject of ongoing discussion.^7,8 Various randomized controlled trials have been conducted on this topic. As a general consensus, supported by the latest meta-analysis by Pengfei and associates,⁹ a Double J stent after an “uncomplicated” URS is not necessary, thus avoiding stent-related side effects and complications.^8

–13

All these studies, however, remain vague in their definition of “uncomplicated” vs “complicated” URS. In fact, definitions vary between studies. Therefore, there is a need to unequivocally define ureteral lesions (UL) by an easily employable grading system. Ultimately, this would allow the evaluation of standardized recommendations as to when and for how long a Double J stent should be inserted after ureteroscopy depending on the grade of lesion present.

Patients and Methods

A systematic search of the PubMed^® database was performed for the terms “urolithiasis,” “ureter,” “ureteral,” “ureteric,” “renal,” “calculi,” “stone,” “flexible,” “ureteroscopy,” “ureterorenoscopy,” “injury,” “damage,” “classification,” and “scale” using different combinations.

Previously, a new classification system called the Endoluminal Ureteral Injury Scale, based on the existing American Association for the Surgery of Trauma (AAST) classification of ureteric injuries,¹⁴ (Table 1) had been developed and presented at the Annual Congress of the German Urological Society.¹⁵ In collaboration with the urology department of Barts and The London Hospital, this classification was further refined to accommodate linguistic intricacies and include a reference to the Dindo-modified Clavien Classification of Surgical Complications¹⁶ (Table 2). The present version was termed Postureteroscopic Lesion Scale (PULS) (Table 3).

Table 1.

American Association for the Surgery of Trauma Organ Injury Severity Scale for the Ureter ¹⁴

AAST Organ Injury Severity Scale for the Ureter
Grade I	Hematoma only
Grade II	Laceration <50% of circumference
Grade III	Laceration >50% of circumference
Grade IV	Complete tear <2 cm of devascularization
Grade V	Complete tear >2 cm of devascularization

AAST=American Association for the Surgery of Trauma.

Table 2.

Dindo-Modified Clavien Classification of Surgical Complications ¹⁶

Dindo-modified Clavien Classification of Surgical Complications
Grades	Definition
I	Any deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic, and radiological interventions. Allowed therapeutic regimens include drugs, such as antiemetics, antipyretics, analgesics, diuretics, and electrolytes, and physiotherapy. This grade also includes wound infections opened at the bedside.
II	Requiring pharmacological treatment with drugs other than those allowed for grade 1 complications. Blood transfusions and total parenteral nutrition are also included.
III	Requiring surgical, endoscopic, or radiological intervention
IIIa	Intervention not under general anesthesia
IIIb	Intervention under general anesthesia
IV	Life-threatening complications (including CNS complications)^a requiring IC/ICU-management
Iva	Single-organ dysfunction (including dialysis)
IVb	Multi-organ dysfunction
V	Death of a patient
Suffix “d”	If the patients suffer from a complication at the time of discharge, the suffix “d” (for “disability”) is added to the respective grade of complication. This label indicates the need for a follow-up to fully evaluate the complication.

brain hemorrhage, ischemic stroke, subarrachnoidal bleeding, but excluding transient ischemic attacks.

CNS=central nervous system; IC=intermediate care; ICU=intensive care unit.

Table 3.

Postureteroscopic Lesion Scale

Postureteroscopic Lesion Scale
Grade 0	No lesion	Uncomplicated URS (no grading according to the Dindo-modified Clavien classification of surgical complications)
Grade 1	Superficial mucosal lesion and/or significant mucosal edema/hematoma
Grade 2	Submucosal lesion
Grade 3	Perforation with less than 50% partial transsection	Complicated URS (Grade 3a or b according to the Dindo-modified Clavien classification of surgical complications)
Grade 4	More than 50% partial transsection
Grade 5	Complete transsection

URS=ureterorenoscopy.

Between July 2009 and August 2011, the new classification (PULS) was applied in 435 patients who were treated for urolithiasis or other pathologies (diagnostic URS, tumor ablation, etc.) by either URS or f-URS. Perioperative data and PULS grading as assessed by the operating surgeon, as well as complications other than UL (ie, postoperative fever/urinary tract infection, secondary hydronephrosis/Double J stent placement, readmittance to hospital), Clavien classification, and stone-free rate were recorded.

Interrater reliability between a junior resident, a senior resident, and a specialist was evaluated in a subgroup of 112 patients. At the end of a ureteroscopy, all three surgeons judged the ureteral trauma/lesion according to the PULS (grades 0–5) while closely observing the last endoscopic passage exiting the ureter. Only after the two observers had left the operating room, the surgeon in charge decided whether a Double J stent would be placed after PULS recommendations based on his own observation. The ratings of each individual observer were recorded, and interrater reliability was validated using Kendall and Spearman tests.

Double J stent placement was performed according to PULS as follows: For PULS grade 0 (no lesion) and 5 (complete tear), treatment followed the generally accepted approaches, namely, no ureteral stent after uncomplicated URS^9,11 and open reconstruction after complete tear.¹⁷

For PULS grades 1 to 4, a comprehensive empiric time-tested treatment schedule, based on 30 years of ureteroscopic surgery experience at both institutions, was used:

• A superficial mucosal lesion (grade 1) was treated by ureteral stent placement for 2 days to account for postoperative edema and temporary hydronephrosis. A Double J stent with a suture attached to the distal end was used, and the suture was fixed outside the external urethral meatus with sticky tape. After 2 days, the stent was simply pulled out without the need for cystoscopy.

• A submucosal lesion with complete tearing of the mucosa (grade 2), typically caused by ureteral dilation, the use of an access sheath, or the ureteroscope itself, was treated by ureteral stent placement for 10 to 14 days. This is a sufficient period to allow for granulation and epithelialization.¹⁸

• A localized perforation (grade 3) was treated by ureteral stent placement for 4 weeks to allow enough time for healing of the urothelial layer, which takes 3 to 4 weeks.^19,20

• In cases of a laceration of more than 50% of the circumference with a preserved tissue bridge (grade 4), a ureteral stent was left indwelling for 6 to 8 weeks; this period corresponds to the estimated healing time for all ureteral layers.^21,22

All patients were followed up either at our own outpatient clinic or by an office-based associated urologist. Postoperative follow-up included a full medical interim history, physical examination, serum creatinine levels examination, and renal sonography. Patients with residual or recurrent urolithiasis and/or ongoing treatment for urolithiasis were excluded from the study. Symptom-free patients without postoperative complications, a significant rise in serum creatinine level (>25% of preoperative value), or signs of obstruction on sonography during the follow-up period were considered to have been treated effectively with no late complications as a result of the ureteral iatrogenic lesions.

Results

This study included 435 patients (121 women [28%] and 314 men [72%]; mean age 53 years [range 16–87 years]). Indications for ureteroscopy were as follows: 337 urolithiasis, 78 diagnostic, 18 laser ablation for tumor, and 2 extraction of foreign body (encrusted Double J stent). All patients received perioperative antibiotic prophylaxis (ciprofloxacin or another antibiotic if earlier antibiograms warranted it).

A total of 261 (60%) patients were treated using URS, and 174 (40%) were treated by f-URS. f-URS included use of an access sheath in 111 (63.8%) cases. Operative times were on average 31 minutes (5–120 min) and 65 minutes (20–160 min) for URS and f-URS, respectively. Stone-free rates were 100% for ureteral stones and 98.1% for renal stones. Early and late complications and Clavien classification (with PULS grade 3+ injuries graded as Clavien grade 3) are shown in Table 4.

Table 4.

Early And Late Complications and Clavien Grading of Ureteroscopically Treated Patients

Complications (n=435)	42 (9.7%)
Intraop.:
Ureteral perforation (PULS 3=Clavien 3)	17 (3.9%)
Postop.:
Symptomatic UTI/antibiotic treatment (Clavien 2)		12 (2.9%)
Secondary hydronephrosis/ DJ stent (within 30 days, Clavien 3)		9 (2.1%)
DJ intolerance (early removal) (n=243)		14 (5.8%)
Readmittance to hospital (within 30 days)		7 (1.6%)
Dindo-modified Clavien grading
1		Not recorded
2		12 (2.9%)
3		26 (6.0%)
4/5		None

Intraop=intraoperative; PULS=Postureteroscopic Lesion Scale; postop=postoperative; UTI=urinary tract infection; DJ=Double J.

Of 435 patients, 46.2% had no UL (grade 0). A grade 1, 2, or 3 lesion was seen in 134 (30.8%), 83 (19.1%), and 17 (3.9%) patients, respectively. No grade 4 or 5 injuries were observed in our series (Table 5). Patients with UL grade 1, 2, or 3 were treated by Double J stent placement for 2 days, 10 to 14 days, and 3 to 4 weeks, respectively. Stent removal was performed by pulling on the attached string (in cases of 2 days stent placement, as described above) or by flexible cystoscopy under local anesthesia.

Table 5.

Gradings In Postureteroscopic Lesion Scale

PULS gradings of ureteroscopically treated patients (n=435)
Grade	n
0	201 (46.2%)
1	134 (30.8%)
2	83 (19.1%)
3	17 (3.9%)
4 or 5	0 (0%)

Nine (2.1%) patients who had been classified “no lesion” (grade 0) and therefore not been provided with a Double J stent during the operation had to have stent insertion later (within 30 days postoperatively) because of secondary hydronephrosis and/or persistent flank pain. Stent intolerance (dysuria or pain) with consequent early removal was seen in 14 (5.8%) of the 243 patients with stents. These incidences (secondary hydronephrosis and stent intolerance) accounted for six readmissions (one additional patient was admitted for fever/urinary tract infection).

Interrater reliability in general was high. This was particularly true between the senior resident and specialist, compared with the junior resident and the senior resident or the specialist (Table 6).

Table 6.

Interrater Reliability of the Postureteroscopic Lesion Scale

Interrater reliability PULS (n=112)
	Overall: Junior vs senior vs experienced surgeon	Junior vs senior resident	Junior resident vs experienced surgeon	Senior resident vs experienced surgeon
Kendall W	0.91	0.92	0.90	0.98
Spearman Rho	0.86	0.83	0.79	0.95

PUL=Postureteroscopic Lesion Scale.

After stent removal and follow-up for an average of 11.7 months (1–25 mos), no clinical or sonographic signs of renal obstruction or significant elevations in serum creatinine level (n=410) were observed. Nine (2.0%) patients were excluded from the study during follow-up because of recurrent stone formation and/or stone treatment. Sixteen (3.7%) patients were lost to follow-up.

Discussion

UL are usually described using the AAST organ injury severity scale for the ureter¹⁴ (Table 1). This grading system has been taken over by the European Association of Urology guidelines committee.¹⁷ Generally, UL are rare and account for only 1% of genitourinary injuries, with 75% of these being iatrogenic, 18% result from blunt trauma, and 7% from penetrating trauma.¹⁴ General recommendations specify that UL grades I to II (laceration <50% of circumference) should be treated by ureteral stent placement or placement of a nephrostomy tube, and that UL grades III to V should be treated by open reconstructive surgery.¹⁷

The Dindo-modified Clavien classification of surgical complications (Table 2) defines and grades postoperative complications based on the therapy used to manage a complication.¹⁶ Both AAST and Clavien classification, however, are of limited value in the context of ureteroscopic procedures and resulting ureteral trauma.²³ The new classification system (PULS, Table 3) proposed in this study is more user-friendly in clinical applications and is associated with a high interrater reliability.

The most common type of ureteral damage during URS is some degree of mucosal or submucosal lesion. Possible causes of intraoperative ureteral trauma include large diameter of the instruments inserted, traumatic passage of instruments during insertion, intraureteral lithotripsy, ureteral dilation, and the use of access sheaths. Postoperative Double J stent placement for varying periods, in particular if UL have been identified, is common practice. It is generally agreed that short-term placement of an ureteral stent (after URS) or a nephrostomy tube (after percutaneous nephrolithotripsy, PCNL) is an integral part of the procedure rather than a complication,^23,24 not unlike a surgical drain after open surgery.

Nevertheless, because ureteral stent placement is associated with considerable morbidity, such as urinary frequency, urgency, and pain,¹² indications for Double J stent insertion should be based on solid evidence. According to two current meta-analyses,^9,13 it seems appropriate to leave patients without a stent after uncomplicated URS, whereas as complicated cases warrant postoperative ureteral stent placement or any other adjuvant treatment. These studies, however, do not provide a clear distinction between uncomplicated and complicated cases. Minor trauma or injuries and the respective treatment might be classified as complications in a generally applicable system, such as the Clavien classification. Therefore, the need for a management-modified Clavien classification for specific procedures such as URS and PCNL has been postulated previously.²⁴

Consequently, the new classification system was developed. Over several years, minor changes in definitions of the grading of the respective UL were adopted until the final version, comprising implications for rating according to the Dindo-modified Clavien classification of surgical complications, was accepted for use (Table 3). PULS grades 1 and 2 represent minor lesions and consecutive treatment (Double J stent) can be seen as an integral part of the procedure. We suggest that these grades should not be addressed as (postoperative) complications in the Clavien classification. In contrast, PULS grades 3 to 5 are major lesions/injuries that afford postoperative treatment by Double J stent placement for several weeks or surgery and therefore “translate” into Clavien complications grade IIIa (under local anesthesia) or IIIb (under general anesthesia).

As realized in the original AAST scales, we attempted to keep descriptions of the different grades as simple as possible, yet clear and distinctive. This allowed for a high interrater reliability (Table 6). Notably, it was higher between more experienced observers—ie, the senior resident and the specialist—than between the junior resident and the senior resident or specialist.

In contrast to the AAST scale, PULS describes trauma to the ureter more precisely in the setting of ureteroscopic surgery. The AAST scale has been developed for injuries through an external trauma, such as accidents or open surgery. Ureteral injuries through ureteroscopic treatment are from inside to outside, which in itself demands a different perspective. Our series shows that 96.1% of patients were rated PULS 0 to 2 (no lesion, superficial mucosal, or submucosal lesions, respectively). As pointed out above, these procedures should be considered an uncomplicated URS and therefore be graded as no complication according to the Dindo-modified Clavien classification. Nevertheless, our experience shows that patients with superficial defects PULS 1 and 2 (30.8% and 19.1%, respectively) will benefit from a short period of postoperative ureteral stent placement.

Because the available meta-analyses on postureteroscopic stent placement^13,23,24 do not differentiate between grades of ULs, there are no data conducive to recommendations as to whether and for how long ureteral stent placement should be applied in cases of superficial or deeper lesions.

Regarding indication and duration of postprocedural ureteral stent placement, our data support the proposed schedule, which is based on long-term empiric evidence from two major tertiary international centers specialized in treatment of patients with urolithiasis:

• Ureteral stent placement for 2 days (PULS 1) and 10 to 14 days (PULS 2) leads to low rates of early readmissions (eg, for symptomatic hydronephrosis from postoperative edema after superficial lesions) and decreased secondary hydronephrosis from ureteral stricture during follow-up.

• The same applies to PULS 3, according to which 17 (3.9%) cases had been treated by ureteral stent plcement for 3 to 4 weeks.

These are empiric “safe” indwelling times. Latest reports show that the duration of stent placement might potentially be reduced, because even after balloon dilation of the ureteral orifice, stent placement is not mandatory,²⁵ and favorable results are seen within 2 to 3 weeks of stent placement after endopyelotomy.^26,27

Conclusion

PULS is an attempt to standardize clinical practice in the conversely discussed field of post-URS stent placement. Whereas adjuvant treatment of major lesions is defined more clearly, there remains a large grey zone for no or minor lesions after URS. First, lesions have to be clearly defined and classified. PULS provides such a classification. Second, PULS required validation with respect to clinical applicability and interobserver reliability. These parameters have been studied using a sufficiently large cohort of patients, and the results are encouraging.

Finally, recommendations for post-URS Double J stent insertion can be derived from such a classification combined with clinical experience. Again, PULS provides a platform for such recommendations that have been integrated on an empiric basis.

Admittedly, follow-up is short (<1 year) and relies on indirect assessments (ultrasonography for strictures). More invasive diagnostics, however, with the use of instrumentation or contrast media would not be ethically acceptable.

Currently, an international multicentric study is under way to further evaluate interrater reliability of PULS. Eventually, this might pave the way for a randomized controlled trial on postoperative stent placement after URS.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

References

Johnson

, Portela

, Grasso

. Advanced ureteroscopy: Wireless and sheathless. J Endourol, 2006; 20:552–555.

Geavlete

, Georgescu

, Nita

et al. Complications of 2735 retrograde semirigid ureteroscopy procedures: A single-center experience. J Endourol, 2006; 20:179–185.

Bader

, Sroka

, Gratzke

et al. Laser therapy for upper urinary tract transitional cell carcinoma: Indications and management. Eur Urol, 2009; 56:65–71.

Breda

, Ogunyemi

, Leppert

, Schulam

. Flexible ureteroscopy and laser lithotripsy for multiple unilateral intrarenal stones. Eur Urol, 2009; 55:1190–1196.

Perlmutter

, Talug

, Tarry

et al. Impact of stone location on success rates of endoscopic lithotripsy for nephrolithiasis. Urology, 2008; 71:214–217.

Schoenthaler

, Wilhelm

, Katzenwadel

et al.

Retrograde intrarenal surgery in treatment of nephrolithiasis: Is a 100% stone-free rate achievable?

J Endourol, 2012; 26:489–493.

Keeley

Jr , Timoney

. Routine stenting after ureteroscopy: Think again. Eur Urol, 2007; 52:642–644.

Damiano

, Autorino

, Esposito

et al. Stent positioning after ureteroscopy for urinary calculi: The question is still open. Eur Urol., 2004; 46:381–388.

Pengfei

, Yutao

, Jie

et al. The results of ureteral stenting after ureteroscopic lithotripsy for ureteral calculi: A systematic review and meta-analysis. J Urol, 2011; 186:1904–1909.

10.

Djaladat

, Tajik

, Payandemehr

, Alehashemi

. Ureteral catheterization in uncomplicated ureterolithotripsy: A randomized, controlled trial. Eur Urol, 2007; 52:836–841.

11.

Tang

, Gao

, Xu

et al.

Placement of ureteral stent after uncomplicated ureteroscopy: Do we really need it?

Urology, 2011; 78:1248–1256.

12.

Nabi

, Cook

, N'Dow

, McClinton

. Outcomes of stenting after uncomplicated ureteroscopy: Systematic review and meta-analysis. BMJ, 2007; 334:572.

13.

Makarov

, Trock

, Allaf

, Matlaga

. The effect of ureteral stent placement on post-ureteroscopy complications: A meta-analysis. Urology, 2008; 71:796–800

14.

Moore

, Cogbill

, Jurkovich

et al. Organ injury scaling. III: Chest wall, abdominal vascular, ureter, bladder, and urethra. J Trauma, 1992; 33:337–339.

15.

Miernik

, Schönthaler

, Wilhelm

, Wetterauer

. Validierung einer Klassifkation endoluminaler Harnleiterverletzungen (Endoluminal Ureteral Injury Scale, EUIS) im Rahmen endourologischer Therapien (modifiziert nach AAST/EAU) Der Urologe, 2011; 50,suppl 1:24.

16.

Dindo

, Demartines

, Clavien

. Classification of surgical complications: A new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg, 2004; 240:205–213.

17.

Lynch

, Martinez-Pineiro

, Plas

et al. EAU guidelines on urological trauma. Eur Urol, 2005; 47:1–15

18.

F. Pollock

, Brunicardi

, Andersen

et al. The cellular, biochemical, and mechanical phases of wound healing. Brunicardi

, Andersen

, Billiar

, Dunn

, Hunter

. Schwartz's Principles of Surgery, 9 ^th. New York: McGraw-Hill Professional, 2009.

19.

Andreoni

, Lin

, Olweny

et al. Comprehensive evaluation of ureteral healing after electrosurgical endopyelotomy in a porcine model: Original report and review of the literature. J Urol, 2004; 171:859–869.

20.

Davis

, Strong

, Drake

. Intubated ureterotomy; experimental work and clinical results. J Urol, 1948; 59:851–862.

21.

Rehman

, Ragab

, Venkatesh

et al. Smooth-muscle regeneration after electrosurgical endopyelotomy in a porcine model as confirmed by electron microscopy. J Endourol, 2004; 18:982–988.

22.

Tallai

, Salah

, Flasko

et al. Endopyelotomy in childhood: Our experience with 37 patients. J Endourol, 2004; 18:952–958.

23.

Rioja

, Mamoulakis

, Sodha

et al. A plea for centralized care for ureteroscopy: Results from a comparative study under different conditions within the same center. J Endourol, 2011; 25:425–429.

24.

Tefekli

, Ali Karadag

, Tepeler

et al. Classification of percutaneous nephrolithotomy complications using the modified clavien grading system: Looking for a standard. Eur Urol, 2008; 53:184–190.

25.

Baseskioglu

, Sofikerim

, Demirtas

et al. Is ureteral stenting really necessary after ureteroscopic lithotripsy with balloon dilatation of ureteral orifice? A multi-institutional randomized controlled study. World J Urol, 2011; 29:731–736.

26.

Mandhani

, Kapoor

, Zaman

et al.

Is a 2-week duration sufficient for stenting in endopyelotomy?

J Urol, 2003; 169:886–889.

27.

Soria

, Rioja

, Blas

et al. Evaluation of the duration of ureteral stenting following endopyelotomy: Animal study. Int J Urol, 2006; 13:1333–1338.

Postureteroscopic Lesion Scale: A New Management Modified Organ Injury Scale—Evaluation in 435 Ureteroscopic Patients

Abstract

Background and Purpose:

Patients and Methods:

Results:

Conclusions:

Introduction

Patients and Methods

Results

Discussion

Conclusion

Footnotes

Disclosure Statement

Abbreviations Used

References