DiSALLE, Judge:

Appellant, Alvin Miller, was found guilty in a jury trial of kidnapping, unlawful restraint, false imprisonment, simple assault, terroristic threats, and theft. The jury rejected appellant's contention that he was not guilty by reason of insanity. On April 14, 1980, appellant was sentenced to be imprisoned for a minimum of four years and a maximum of ten years. This appeal follows the denial of his post-trial motions.

Appellant's first contention is that the lower court erred in not declaring a mistrial when the prosecution asked Dr. Brickhouse, a psychiatrist appearing on behalf of appellant, whether he was aware that appellant had been "found sane in Florida." We disagree.

In reviewing a mistrial motion on appeal we are initially guided by the rule that trial courts are granted discretionary powers, . . . and their rulings "will not be reversed unless there is a flagrant abuse of discretion." . . . In determining whether to grant the request, the necessary inquiry is whether the alleged occurrence was prejudicial to the defendant, "that is, [whether] it is of such a nature . . . that it may reasonably be said to have deprived the defendant of a fair and impartial trial."

(citations omitted). Commonwealth v. Farrell, 265 Pa. Super. 41, 52-53, 401 A.2d 790, 796 (1979).

Here, the offending question, taken in context, and followed, as it was, by the prosecution's clarifying statement to the jury and the lower court's curative instruction to the jury was not so prejudicial as to require a mistrial. The lower court, therefore, did not abuse its discretion in denying appellant's motion. Id.

Appellant's second contention is that the lower court erred in not permitting Dr. Patterson, another psychiatrist appearing on behalf of appellant, to testify as to the probable length of appellant's treatment if he was adjudicated insane and committed to an institution. Appellant argues that such information is a "natural extension" of Commonwealth v. Mulgrew, 475 Pa. 271, 380 A.2d 349 (1977).

In Mulgrew, our Supreme Court held that a jury must be given an explanation of what would be the consequences of a verdict of not guilty by reason of insanity. The Court adopted as its rationale the language of Lyles v. United States, (citation omitted), which held:

"The issue of insanity having been fairly raised, the jury may return one of three verdicts, guilty, not guilty, or not guilty by reason of insanity. Jurors, in common with people in general, are aware of the meanings of verdicts of guilty and not guilty. . . . But a verdict of not guilty by reason of insanity has no such commonly understood meaning. . . . It means neither freedom nor punishment. It means the accused will be confined in a hospital for the mentally ill until the superintendent of such hospital certifies, and the court is satisfied, that such person has recovered his sanity and will not in the reasonable future be dangerous to himself or others. We think the jury has a right to know the meaning of this possible verdict as accurately as it knows by common knowledge the meaning of the other two possible verdicts." (Emphasis added.)

Mulgrew, 475 Pa. at 275-76, 380 A.2d at 351.

Here, the lower court instructed the jury that "when a defendant is found not guilty by reason of insanity, he may be the subject of an immediate court proceeding to commit him to a mental treatment facility; and if committed, his commitment will continue as long as there is found a reasonable probability that similar conduct will be repeated." We find this instruction to be in compliance with Mulgrew.

We expressly reject appellant's argument that we should expand Mulgrew. To permit, as appellant advocates, a defendant to present testimony as to the probable length of his commitment would only serve to cloud the issue of his guilt. The lower court correctly pointed out that, "[t]he length of commitment, be it to a penal institution or a mental institution, is not relevant to any determination in that the jury might properly be called upon to make." See III ABA Standards For Criminal Justice § 18-1.1 (2d ed. 1980).

Appellant's third contention is that the lower court erred in denying his motion for bifurcation of the trial. The Act of July 9, 1976, P.L. 817, No. 143, § 404, effective in 60 days; 50 P. S. § 7404(c) (Supp. 1981-82). He argues that the insanity defense made it difficult for the jury to consider the other defenses he raised, thereby denying him a fair and impartial trial. These other defenses consisted solely of appellant's failure to remember or be aware of certain events: placing the rope around the victim's neck, threatening the victim, and stealing the victim's car.

The lower court determined that bifurcation was not necessary because the issues were "straightforward enough" and that bifurcation would result in two almost identical trials utilizing the same witnesses and evidence. We agree and hold that the lower court did not abuse its discretion in refusing bifurcation. 50 P. S. § 7404(c). See 1 Pa.C.S.A. § 1903 ("words . . . shall be construed according to their common and approved usage. . . .").

It is clear that appellant's other defenses were not separate defenses, but were, in fact, rooted in his insanity defense. Therefore, once the jury rejected appellant's insanity defense, they were free to find him guilty of the charges against him based upon the Commonwealth's uncontested evidence.

Appellant's final contention is that the lower court erred in not instructing the jury that they should return a verdict of not guilty by reason of insanity if they found that appellant's actions were the offspring or product of a mental disorder. Appellant argues that our court should reexamine the presently used M'Naghten test for legal insanity in light of recent advancements in psychology.

We reject appellant's argument and rely on our Supreme Court's recent reaffirmation of the M'Naghten test in Commonwealth v. Hicks, 483 Pa. 305, 396 A.2d 1183 (1979). The lower court's charge to the jury was in accordance with the M'Naghten test and, therefore, proper.

Judgment of sentence affirmed.