LVM Encrypted Partition without Partition Table

I have the following Problem. My Laptop is fully encrypted with LVM I know the Passphrase, but the partition table is broken. I booted from an USB Stick in this Case sdb1. Is there any hope to get /dev/sda2 working again? sda1 ist mountable If I try to boot I will fall into initframs with no Volumne Groups found.

System is a Linux Mint Qiana.

 sudo fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000ca01e

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      499711      248832   83  Linux
/dev/sda2          501758   976771071   488134657    5  Extended
Partition 2 does not start on physical sector boundary.

Disk /dev/sdb: 31.9 GB, 31910264832 bytes
255 heads, 63 sectors/track, 3879 cylinders, total 62324736 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00023cc3

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048    62324735    31161344    c  W95 FAT32 (LBA)

Thanks for any help