(concurring specially).
Although I concur in the majority’s resolution of the case dismissing the appeal as moot, I believe that an elaboration on mootness is in order since my reasons for dismissing the appeal as moot are different from the other members of the panel. It is well established that if pending an appeal, an event occurs which renders it impossible to grant any relief or which makes a decision unnecessary, the appeal will be dismissed. In re Township of Glendale, Scott County, 288 Minn. 340, 343, 180 N.W.2d 925, 927 (1970); Barnes v. Macken, 252 Minn. 412, 415, 90 N.W.2d 222, 226 (1958). Further, decisions by a court “should be limited to real controversies involving existing facts and rights asserted thereunder.” Dehning v. Marshall Produce Co., 215 Minn. 339, 340, 10 N.W.2d 229, 229 (1943).
A supersedeas bond is not a prerequisite to securing appellate review. Tourville v. Tourville, 289 Minn. 544, 185 N.W.2d 281 (1971). Rule 108.01 of the Minnesota Rules of Civil Appellate Procedure provides that proceedings in the trial court shall be stayed and save all the rights thereby affected if the appellant posts a supersedeas bond “in the amount and from which the trial court shall order and approve * * *.” Moreover, upon motion, the trial court has the discretion to require the filing of a supersedeas bond “if it determines that the provisions of Rule 108 do not provide adequate security to the respondent.” Minn.R.Civ.App.P. 108.01, subd. 7. See State v. Northern Pacific Railway Co., 221 Minn. 400, 22 N.W.2d 569 (1946).
Here, appellant was required to file a supersedeas bond equal to llk times the amount of each lien claim. Appellant refused to do this despite this court’s July 30, 1985 order denying appellant’s motion to reduce or vacate the bond as excessive under Sisto v. Housing and Redevelopment Authority of Duluth, 258 Minn. 391, 104 N.W.2d 529 (1960). Further, appellant’s petition for review of this decision to the supreme court was denied.
Appellant’s claim that the trial court was without jurisdiction to discharge the lis pendens is similarly without merit. In Scofield v. Scheaffer, 104 Minn. 127, 116 N.W. 211 (1908), the trial court retained jurisdiction for purposes of executing a judgment when the appellant failed to file a superse-deas bond. Appellant should not be heard to complain when its own inaction vested the trial court with the power to discharge the lis pendens during pendency of the appeal. Minn.Stat. § 514.08 (1982) provides in part:
The lien shall cease at the end of 90 days after doing the last of such work, or furnishing the last item of such skill, material, or machinery, unless within such period:
(1) A statement of the claim therefor, be filed with the county recorder of the county in which the improved premises are situated, * * *.
The logical import of this provision is that once a lien statement is filed of record, it must be maintained of record after that time. Failure to do so is a fatal defect to a continuing claim that a mechanics lien exists. In reference to the lis pendens, Minn. Stat. § 514.12, subd. 3 (1982) provides in part:
[A]s to a bona fide purchaser, mortgagee, or encumbrancer without notice, the *250absence from the record of a notice of lis pendens of an action after the expiration of the year in which the lien could be so asserted shall be conclusive evidence that the lien may no longer be enforced * * *.
Since both the mechanics lien and the lis pendens were discharged on October 9, 1985, appellant no longer has a basis for enforcement of his claim. The issues are moot and the case should therefore be dismissed.