【Introduction】

TSS (Tandem Spine Stenosis) is increasing, but the pathophysiology and pathogenesis are unclear, and there is no consensus on the surgical procedure as to whether it is one-stage or 2-stage. We compared spinal alignments, clinical symptoms, skeletal muscle mass, and surgical results between TSS patients who underwent simultaneous cervical and lumbar decompression and lumbar spinal stenosis (LSS) patients who underwent lumbar decompression, and the characteristics of the TSS patient and the usefulness of one-stage surgery were examined.

【Methods】

The subjects were 82 patients who visited our outpatient department of orthopedics, received surgical treatment. Of the 82 cases, TSS was 13 cases and LSS was 69 cases. Regarding the evaluation of spinal alignments, Lumbar scoliosis (LS),  Sagittal vertical axis (SVA),Lumbar lordosis (LL), Pelvic tilt (PT), Pelvic incidence (PI), and Sacral slope (SS) were evaluated. Regarding the evaluation of clinical symptoms, the visual analogue scale (VAS) score for low back pain (LBP) and leg pain and leg numbness, the Japanese Orthopedic Association scoring system (JOA score), the Roland-Morris Disability Questionnaire (RDQ), the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ), and Oswestry Disability Index (ODI) were evaluated. A bioelectrical impedance analyzer (BIA) was used to measure systemic skeletal muscle mass and phase angle, which is an index of cell membrane aging. Preoperative skeletal muscle mass, phase angle, clinical symptoms, and surgical results were compared and examined in both groups.

【Results】

The operation time was significantly longer in the TSS group than in the LSS group (p <.05), but the amount of bleeding was not significantly different between the two groups (p> .05). In addition, phase angle of the trunk and both lower limbs were significantly lower in the TSS group than in the LSS group (p <.05). Postoperative SVA, LL, PT, and SS in the TSS group were insignificantly improved and in the LSS group were significantly improved. Regarding preoperative clinical symptoms, the proportion of JOABPEQ gait dysfunction that was difficult to climb stairs was 83% in the TSS group, and social life disturbance that was difficult to engage in ordinary activities was 67% in the TSS group, which were significantly higher than that in the LSS group (p <.05). Although clinical symptoms improved by surgery in both groups (p <.05), there was no significant difference in the degree of clinical symptom improvement (p> .05).

【Discussion】

TSS decreased in the phase angle of the trunk and both lower limbs, suggesting the progression of trunk muscle atrophy and aging due to the decrease in activity. About 85% of TSS cases are characterized by difficulty in climbing stairs, and it was shown that TSS should be treated with TSS in mind in LSS cases where it is difficult to climb stairs. Spinal surgery significantly improved SVA, LL, and PT in LSS, and TSS also showed a tendency to improve spinal alignment.　A one-stage operation was performed on TSS, and the amount of intraoperative bleeding was equivalent to that of LSS alone and minimally invasive. The one-term approach seems to be effective.