Use of the Stone Cone for prevention of calculus retropulsion during holmium:YAG laser lithotripsy: case series and review of the literature.
BACKGROUND
Stone retropulsion during ureteroscopic lithotripsy leads to additional procedures for residual calculi. The Stone Cone (Boston Scientific, Natick, Mass., USA) is a device designed to prevent stone migration.


OBJECTIVE
To determine the incidence of calculus retropulsion and additional procedures after ureteroscopy with intracorporeal lithotripsy while using the Stone Cone.


METHODS
A retrospective review of patients with obstructing ureteral calculi who underwent ureteroscopy and holmium:YAG laser lithotripsy using the Stone Cone as a backstop over a 3-year period at an academic medical center was performed. 133 patients underwent ureteroscopy with holmium:YAG laser lithotripsy using the Stone Cone to prevent calculus retroplusion. Success was defined as no residual fragments >2 mm in size, no changes from semirigid to flexible ureteroscope, and no additional procedures. Post-operative imaging was abdominal plain radiography or computed tomography. A MEDLINE search was performed to indentify all English clinical studies of the Stone Cone.


RESULTS
Of the 133 uses of the Stone Cone, there were 2 (1.5%) residual retropulsed fragments >2 mm which required an additional procedure. There were no changes to flexible ureteroscope secondary to stone retropulsion in 105 cases of semirigid ureteroscopy. There was no instance of ureteral obstruction from residual 2-mm fragments. There were no ureteral strictures or hydronephrosis among 91 patients with long-term follow-up imaging. A review of the literature was performed which yielded 4 clinical publications and 90 reported cases using the Stone Cone with 100% success. Two of these studies showed statistically significant improvement when compared with control patients.


CONCLUSIONS
The Stone Cone minimized stone retropulsion during ureteroscopic laser lithotripsy. The Stone Cone offers the urologist greater certainty during ureteroscopy and may decrease the number of clinically significant residual calculi.
Eisner
Brian H
BH
Kidney Stone Center, Department of Urology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. beisner@partners.org
Dretler
Stephen P
SP
D000046:Academic Medical Centers; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001900:Boston; D002648:Child; D004867:Equipment Design; D005260:Female; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D053844:Lasers, Solid-State / Q000009:adverse effects / Q000627:therapeutic use*; D017602:Lithotripsy, Laser / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000628:therapy*; D018666:Ureteroscopy / Q000009:adverse effects; D055815:Young Adult