The patient was operated by me 20-January-2013 for extruded disc C3-4 and C4-5 with OPLL. The patient showed dramatic improvement after surgery with dramatic recovery of the four limbs. The 5th postoperative day, he showed severe deterioration of the power of the left upper and lower limb.

On examination 05-February-2013: The patient is limping with inability to walk alone due to severe weak left side of the body. The patient is unable to extend or flex the left hand. The power of the left foot is 5/5 but the quadriceps is weak 3/5. There is hypalgesia of the thumb of the left hand and both feet. The power of the right limbs are normal. Babinski positive in the left side. The patient sent for investigations.

MRI brain done 10-February-2013 was uneventful with sinusitis. MRI cervical spine showed de novo posterior compression behind the C4-5 level. This elements was not seen in the preoperative MRI. There is also edema of the OPLL elements with slight edema of the spinal cord.

Decompressive laminectomy C3,4,5 and upper half of C6 and lower third of C2. There is no epidural fat and the dura have slight pulsation.

Routine closure of the wound. Smooth postoperative recovery. The neurological status of the patient still the same.

Usually deterioration take place immediately after surgery if iatrogenic injury is the cause. Here the deterioration took place 5 days after dramatic improvement. Edema of the OPLL structures is not reported in the literature, but here it is well demonstrated by the MRI findings. This edema could take gradual onset and it is not clear why it became swollen.

The area is fixed by plate and screws and the posterior compression also cannot be understood, why it emerged after surgery. MRI is still not reliable for reading. This posterior compression could have place before surgery, or it is de novo event. The presence of this posterior compression mandate posterior decompression.