Try this,
First Create a UIButton then Create one UIBarButtonItem with Custom view, considering UIButton as custom view for UIBarButtonItem.
Consider button to target event for popping view controller.
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(0, 0, 35, 35);
[button setImage:[UIImage imageNamed:@"dots.png"] forState:UIControlStateNormal];
[button addTarget:self action:@selector(backBarButton:) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *backBarButton = [[UIBarButtonItem alloc] initWithCustomView:button];
self.navigationItem.leftBarButtonItem = backBarButton;
- (void)backBarButton:(id)sender {
NSLog(@"%s", __FUNCTION__);
self.navigationController.navigationBarHidden = YES;
[self.navigationController popViewControllerAnimated:YES];
}