The patient  came to the clinic 15-March-2012 complaining of numbness both hands more the left and right foot for one year. She has neck pain for 4 years with weak both lower limbs, that she cannot walk more than 200 meters. The condition is deteriorating. MRI of the cervical spine performed 04-May-2011 showing subluxation of dense of C2 with severe compression of the lower medulla with malacia of the spinal cord. The patient is dwarf with clinical pictures of Morquio's syndrome (MPS IV) with odontoid hypoplasia.

On examination, the patient has waddling gait with all muscles of the four limbs are at best -4/5 with extension of the right hand and dorsiflexion right foot -3/5.Patologic reflexes are present in the four limbs with hyperreflexia of the deep reflexes and clonus both legs. She has hypalgesia of the left upper limb and the right hand and foot.

In the prone position with head under traction of 5 Kg and using image-intensifier to follow the position of C1 posterior ring in relation to the lamina of C2, to be as near as possible to avoid accidental compression of the spinal cord and lower medulla, skeletonization of posterior ring of C1 and the lamina of C2 and the occiput near the foramen and partially the C3 lamina upper half. The ring of C1 is flail, which is a welcome sign. The posterior rim of the foramen magnum was drilled about 6-7 mm to gain further decompression. The spinous process of C2 was nibbled out to be used as bone graft. Using Medtronic Vertix 7 mm to upper edge of C1 and 4.5 mm to the lower edge of C2, fusion of the C1 and C2 was achieved with compression to bring the C1 ring abutting the lamina of C2. Spinal rods 25 mm were used and the bone graft was filled to the area between the rods.

Routine closure of the wound. Smooth postoperative recovery and the power of the four limbs became dramatically better.

The patient has deep tetraparesis with flail C1 compressing the spinal cord and lower medulla. There is malacia of the neural elements due to repetitive mechanical compression. The best option of treatment is to fuse the C1 and C2 without violating the skull base.