Congenital Absence of a Lumbar Pedicle Presenting With Contralateral Lumbar Radiculopathy

Abstract

The authors describe a rare case of a congenital absence of the right L5 pedicle in a 54-year-old man presenting with low back pain and radicular pain of his left leg. Plain x-ray films, computed tomography scan (CT) after myelography, and three-dimensional CT revealed the absence of the L5 pedicle and anomaly of the L4-L5 facet joint on his right side. On the left side, there were severe degenerative changes that were thought to be the result of an overload and instability. The degenerative changes led to late-onset neurologic impairment of the contralateral side, which was treated with spinal fusion. To our knowledge, this is the first report of contralateral symptoms due to unilateral defect of the facet joint accompanied by aplasia of a pedicle.

Congenital hypoplasia or aplasia of the lumbosacral pedicle as an unusual cause of spondylolisthesis in the pediatric age group

“…7,[9][10][11]22 Only a few cases have presented with intractable low-back pain or radiculopathy necessitating surgical intervention. 5,13 To the best of our knowledge, the present report features the first cases of congenital absence or hypoplasia of a lumbosacral pedicle associated with spondylolisthesis and intractable lowback pain requiring surgical stabilization.…”

“…If one of the facet joints is incompetent, the contralateral joint must bear a greater load. 5 In our Case 2, such overload and instability at the lumbosacral junction resulted in severe degenerative changes of the contralateral L5-S1 facet joint. Kaito et al 5 reported a similar condition in which the unilateral absence of an L-5 pedicle resulted in degeneration in the contralateral facet joint.…”

“…5 The main role of the facet joints at the lumbosacral junction is stabilization against extension and rotation stresses. 8,16 Biomechanical tests have demonstrated that total facetectomy, even unilaterally, makes the lumbosacral spine significantly unstable in axial rotation and flexion.…”

“…When this anomaly does come to clinical attention, low-back pain is the only associated symptom reported thus far. 5 To the best of our knowledge, our 2 cases are the first instances of the absence or hypoplasia of the pedicles of the lumbar spine or sacrum associated with low-back pain and spondylolisthesis in the pediatric age group.…”

“…The absence of a lumbar or sacral pedicle is extremely rare. 2,[4][5][6]14,15,21 Most cases of absent or hypoplastic lumbosacral pedicles are asymptomatic and usually found incidentally on diagnostic imaging. When this anomaly does come to clinical attention, low-back pain is the only associated symptom reported thus far.…”