试图从数组PHP中删除会话数组

Im trying to remove a session['cart_items] array from a multi array and I can't seem to get the delete part to work.

I'm getting the id through: $_POST['product] however I've tried the following and getting a bit stuck:

$temp = array_flip($_SESSION['cart_items']);    
unset($_SESSION['cart_items'][$temp[$_POST['product']]]);

I've also tried:

unset($_SESSION['cart_items'][$key]);

My output is:

Array
(
[0] => Array
    (
        [0] => Array
            (
                [item_id] => 407
                [item_name] => Am I Bothered? About Homophobia
                [item_qty] => 22
            )

    )

)

An help would be great

Multiple array result:

array(1) {
  ["cart_items"]=>
array(2) {
[1]=>
array(1) {
  [0]=>
  array(3) {
    ["item_id"]=>
    string(3) "407"
    ["item_name"]=>
    string(31) "Am I Bothered? About Homophobia"
    ["item_qty"]=>
    string(2) "50"
  }
}
[2]=>
array(1) {
  [0]=>
  array(3) {
    ["item_id"]=>
    string(4) "1131"
    ["item_name"]=>
    string(50) "10 Ways A Condom Can’t Protect You – Postcards"
    ["item_qty"]=>
    string(2) "14"
  }
}
}
}

for(i=0;i<sizeof($_SESSION['cart_items'][0]);i++){
    if($_SESSION['cart_items'][0][i]['item_id'] == $key);
        unset($_SESSION['cart_items'][0][i]['item_id']);
}