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Posterior Lumbar Interbody Fusion (P.L.I.F.) Surgical Techniques

Ruptured Cervical Intervertebral Discs Cervical Spondylosis


Lumbar Disc Lesion

A word from Dr. Cloward

The surgical technique for removal of ruptured lumbar intervertebral discs has changed very little since it was introduced by Mixter and Barr in 1934. Protrusion of the nucleus pulposus or intraspinal herniation of fragments of the annulus fibrosus causes unilateral nerve root compression. A unilateral operation, either a hemilaminectomy or an interlaminal approach, is employed to remove the lesion from the spinal canal.

The technique of the interlaminar operation used by early neurosurgeons [Spurling, Semmes, Raaf] consists of a vertical midline skin incision and unilateral stripping of lumbosacral fascia and muscles to exposure of spines and lamina. Part of the ligamentum flavum is removed, a notch is made in one or both margins of the laminae with a rongeur creating an oval opening into the spinal canal 1 to 1.5 cm in diameter directly over or medial to the nerve root. The nerve root is retracted medially to expose the intervertebral disc protrusion. Bleeding from epidural veins is controlled before the disc lesion is visualized and removed. Recently, the procedure of 'micro discectomy' has gained popularity, for improved lighting and smaller incision.

The technical difficulties and surgical failures encountered with this discectomy operation can be partially attributed to an inadequate exposure of the spinal canal. The small unilateral opening precludes extensive exploration above and below and medial to the nerve root necessary to locate and remove multiple and elusive disc fragments. Forceful manual retraction of the nerve root required to arrest bleeding and visualize and remove disc fragments, may account for postoperative pain and neurological deficits.

The primary cause for the low long-term success rate of the "simple" discectomy operation is the failure to recognize the equally important symptoms of low back pain. Loss of the supporting function of the nucleus pulposus results in instability of the 'motion segment" and chronic low back pain. Surgeons remove the protruding disc fragment from the nerve root and relieve the leg pain but ignore the back pain.

There is no unanimity of thought among spine surgeons as to whether a patient should or should not be treated with a spinal fusion operation at the time of the discectomy. Dr. Mixter, one of the founding fathers of lumbar disc surgery replied to this question in 1947: "If an operative procedure can be devised which will give satisfactory fusion as well as satisfactory disc removal, and without lengthening the convalescent period, then I would concur with the idea of a fusion as part of the original operation."

These criteria laid down by Dr. Mixter are fully met by the Posterior Lumbar lnterbody Fusion (P.L.I.F.) operation, originated by the author in 1943. A combined disc removal and interbody fusion has been performed on every patient operated on for lumbar disc disease in over 45 years. More than 2,500 patients have had 92% complete (long-term) cure rate.

The operative technique of P.L.I.F. is not difficult to learn for the average disc surgeon. However, three prerequisites are necessary for success of this operation:

  • The surgeon must be motivated to spend time at the operating table to properly perform and complete the operation.
  • He must have available and be properly trained to use the special instruments designed for and required to do the operation.
  • He should have a bone bank with adequate supply of good quality bone grafts.
If these criteria are met, most lumbar disc operations will be gratifyingly successful.


RALPH B. CLOWARD, M.D.


Copyright 2006 Cloward Instrument Corporation