Listhesis

Listhesis is a medical term used to describe the displacement of a vertebral body relative to the adjacent vertebra below it. In practice, it most often refers to anterior translation of a lumbar vertebra (the condition commonly called spondylolisthesis), but the word can denote displacement in other directions as well, including posterior or lateral slippage. The condition constitutes the mechanism behind spondylolisthesis and is most noticeable on standing lateral spine images.

Causes and classification are broad. Listhesis can arise from congenital or developmental factors (dysplastic type), stress fractures of the pars interarticularis (isthmic type), degenerative changes such as facet joint arthropathy and disc degeneration (degenerative type), traumatic injury, or pathological processes affecting the bone (e.g., tumors or infection). The direction and degree of slip may vary, and grades of slip are commonly described using the Meyerding scale, where Grade I is less than 25% slippage and higher grades represent increasing displacement, with Grade V indicating spondyloptosis (complete anterior dislocation).

Clinical features range from mild, episodic back pain to persistent low back pain with radicular leg symptoms or neurogenic claudication. Some patients may have a palpable step-off in the lower back. The presentation often depends on the level involved and the amount of slip; severe slips or associated neural compression may cause neurological deficits.

Diagnosis typically begins with standing lateral radiographs, sometimes with oblique views, to assess slippage and stability on flexion and extension. MRI provides information about neural elements and soft tissues, while CT can detail bony anatomy when surgical planning is considered.

Treatment is individualized. Conservative management includes analgesia, physical therapy, activity modification, and sometimes bracing, suitable for mild cases. Surgical intervention, usually after failed conservative therapy or in cases of progression or neurological deficit, often involves decompression with spinal fusion (an instrumented fusion). The prognosis depends on slip severity, symptoms, and the presence of instability or neurological involvement. Listhesis is most commonly encountered in the lumbar spine, particularly at L4-L5 and L5-S1 levels.