Influence of the sagittal spinal profile type on the long-term outcome of patients with symptomatic lumbar spinal stenosis after microsurgical decompression

OBJECTIVE Microsurgical decompression for patients with symptomatic lumbar spinal stenosis (LSS) has demonstrated long-term improvement concerning pain and function. Nonetheless, a considerable proportion of these patients do not experience satisfactory alleviation of symptoms. Previous studies have not found a direct influence of single sagittal parameters on patient outcomes. However, recent research indicates that a composite of parameters, presented in specific sagittal profile types (SPTs) that were defined by Roussouly and colleagues, may affect these outcomes. This study aims to investigate the impact of SPT on long-term outcomes of patients with LSS following microsurgical decompression. METHODS This study is a prospective clinical observation. Patients with symptomatic LSS, who underwent microsurgical treatment and had long-term follow-up data for at least 36 months, were included. Patients with spinal deformity, fractures, or significant instability were excluded. Outcomes were measured using the numeric rating scale for pain, 36-Item Short Form Health Survey for quality of life, walking distance, Oswestry Disability Index, Roland-Morris Disability Questionnaire, and Odom's criteria. SPT was determined in blinded fashion by using preoperative long standing radiographs. RESULTS The initial population of this observational study consisted of 128 patients, with long-term results available for 87 individuals, including 24 patients with SPT1, 20 with SPT2, 27 with SPT3, and 16 with SPT4. The average age was 70 years, with a slight male majority (56.3%) and a mean BMI of 27.9 kg/m2. 2 . After a median follow-up of 48 months, all groups showed significant improvement in walking distance, leg pain, and disability. Overall, 75% reported satisfaction with the surgery. However, patients with SPT1, which is characterized by low sacral slope and specific spinal curvatures, experienced significantly less improvement in back pain (p = 0.018) and related disability (p = 0.030), and lower satisfaction compared to other SPT groups (p = 0.008). CONCLUSIONS The sagittal spinal type is influencing the long-term outcome of patients suffering from symptomatic LSS. Patients with a combination of a flat sacral slope and a low overall lumbar lordosis with a high lordosis in the lower lumbar spine (i.e., spinal SPT1) showed worse outcome concerning back pain and had decreased satisfaction with surgery than comparable subjects from other SPT groups. Consequently, the authors recommend the assessment of sagittal spinal types in patients diagnosed with symptomatic spinal stenosis prior to decompression surgery. Inclusion of SPT in the preoperative consultation process can provide valuable insights, potentially guiding practitioners to more tailored patient counseling.