Background context: The selection of appropriate patients for lumbar disc surgery is a challenging task involving a highly variable, multifactorial decision process complicated by a lack of reliable, validated clinical signs and imaging findings. Recently, multiple studies have demonstrated the reliability and diagnostic utility of a standardized form of spinal assessment using repeated end-range test movements while monitoring patterns of pain response (McKenzie assessment).
Purpose: It is the aim of this article to evaluate the utility of this assessment system and its literature support in the selection of candidates for surgery for disc-related pain.
Study design and methods: A literature review.
Results: Most patients under consideration for lumbar disc surgery, when examined using this form of dynamic mechanical spinal evaluation, based on patients' patterns of pain response to standardized repeated end-range lumbar test movements and positions, fall into one of three subgroups: 1) a reversible condition, 2) an irreversible condition or 3) an unaffected condition. Reversible conditions in acute to chronic low back and/or leg pain are recoverable, often rapidly so, using nonoperative self-care dictated by the patient's assessment findings. The elicitation of pain "centralization," an improvement (favorable change) in pain location in response to repetitive end-range testing, typically occurring with only one direction of test movement(s), predicts a high likelihood of successful response to conservative care, even in the presence of neurologic deficits. Irreversible conditions are characterized by symptom aggravation by all directions of testing, including the absence of the centralization response, predicting a poor response to nonsurgical care. In those whose pain is unaffected with similar testing, evidence indicates the pain is likely nondiscogenic. A dynamic disc model has been described as a possible model for these varying pain responses. Insight into annular integrity of symptomatic discs is also provided using this repeated end-range/pain response (McKenzie) assessment.
Conclusions: As described, the literature supports the use of a repeated end-range/pain response assessment (dynamic mechanical evaluation) in obtaining diagnostic and therapeutic information in patients with low back and leg pain. This may contribute to improving the selection process of surgical patients.