Degenerative lumbar stenosis surgery: predictive factors of clinical outcome. Experience with 1001 patients

BACKGROUND: Degenerative lumbar spinal stenosis (DLSS) carries a high risk of morbidity and represents a financial burden to society. A late diagnosis can lead to severe disability. Although lumbar decompressive surgery enjoys a heavy worldwide application, proper preoperative factors to define the ideal candidates for decompression are missing.

MATERIAL AND METHODS: 1001 patients who underwent decompressive surgery from 2012 to 2019 for DLSS were screened for the presence of nine clinical and radiological parameters. For all cases, differences between baseline and post-surgical ODI were calculated and the results were subsequently categorized as five different classes (ranging from a very poor outcome to an excellent one) according to the specific scores. Generalized ordinal logistic regression was then utilized to analyze the significance of the nine parameters (coded as dummy variables) in predicting outcome as measured by ODI improvement after surgery.

RESULTS: eight parameters were found to be significant predictors. Radiological grade of compression was the strongest, followed by polyneuropathy, obesity, symptoms duration, gait autonomy, radicular deficits, ASA score and levels of surgery. Conversely, having undergone a previous back surgery did not predict outcome.

CONCLUSION: Our findings indicate that the ideal candidate for surgery has the following pre-surgical characteristics: Schizas grade D, no signs of peripheral polyneuropathy, BMI < 30 kg/m2, symptom duration < 2 years, gait autonomy inferior to 100 meters, no radicular deficits, one level of stenosis, and an ASA score of 1, 2 or 3.