"Reasonable threshold" of spinopelvic parameters after fixation on distal stenosis in patients with degenerative thoracolumbar kyphosis: A STROBE-compliant article

The short-segment instrument for precision treatment of lumbar stenosis syndrome (LSS) combined with degenerative thoracolumbar kyphosis (DTLK) receives more attention and the reasonable range of sagittal parameters is debatable in these elderly patients. This study aimed to include LSS patients combined with DTLK performed short-segmental fixation on LSS, to evaluate the efficacy of this procedure, and to determine the reasonable threshold of sagittal parameters. Overall 138 patients (female, 62.3%) were eligible (mean age of 68.8 ± 7.7 years) with a follow-up time of 24.6 ± 11.1 months. Spinopelvic sagittal parameters containing TLK, lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sagittal vertical axis were obtained at baseline and final visit, where |PI-LL|, PT, and sagittal vertical axis were seen as the main parameters. Quality of life was evaluated by the Oswestry Disability Index (ODI), which were divided into 4 quarters orderly. The reasonable threshold of parameters corresponding to ODI was determined by both linear regression and logistic regression. For all participants, TLK decreased by a mean of 8.3° and cases got TLK correction occupied 40.4%. ODI got improvement by the change of 29.9 ± 9.9. At baseline, ODI was correlated to |PI-LL|, while at final, ODI was correlated to |PI-LL| and PT. The independent factor affecting preoperative ODI was |PI-LL|, with ODI = 0.19 × |PI-LL| + 36.9 and the mean threshold of preoperative |PI-LL| was 10.7°. At final, PT was the influencing factor with ODI = 0.21 × PT + 3.16 and PT = 0.60 × |PI-LL| + 12.22. The mean threshold of postoperative |PI-LL| was 16.0° and PT was 23.1° by both linear regression and logistic regression. With short-segment fixation on LSS, >40% of patients with DTLK acquired TLK correction. |PI-LL| = 16.0° and PT = 23.1° was the "reasonable threshold" of sagittal parameters with the procedure for this population.

Posterior instrumented fusion on lumbar stenosis syndrome can bring benefit to proximal degenerative kyphosis: A CONSORT-compliant article

ABSTRACT

The effect on degenerative thoracolumbar kyphosis (DTLK) after short-segment instrument for lumbar spinal stenosis syndrome (LSS) remains controversial. Based on the biomechanics and compensatory of the global spino-pelvic alignment, it was assumed that the interference on the lumbar spine, instead of the thoracolumbar segment, could still make a difference on the proximal spine.To explore whether DTLK could improve with only surgery for LSS and identify influencing factors on postoperative TLK.The study was performed from January 2016 to December 2018. Sixty-nine participants (25 male) diagnosed LSS with DTLK were enrolled and surgery was only for LSS. Radiological parameters included TLK, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, and osteoporosis. Clinical outcomes were visual analogue scale and Oswestry disability index. According to lower instrumented vertebrae (LIV) on L5 or S1, inter-group comparisons were performed between LIV on L5 (L5 group) and S1 (S1 group).Demographics were well-matched between L5 and S1 group with a mean follow-up of 24.3 ± 12.1 (m). TLK improved with a mean of 16.2 ± 7.6 (°) (P < .001). There was no significance on radiological and clinical parameters between L5 and S1 groups except for a larger pelvic tilt in S1 group (P = .046). Visual analogue scale (P = .787) and Oswestry disability index (P = .530) were both indifferent between normal TLK and DTLK at last (P > .05). Postoperative TLK was affected by osteoporosis and sacral slope, the latter was dominated by pelvic incidence and pelvic rotation. Osteoporosis was the risk factor for TLK correction (P = .001, odd risk = 9.58).DTLK decreased if instrument only performed for LSS, where TLK and clinical outcomes are comparably affected whether L5 or S1 is selected as LIV. This study supplements the compensatory mechanism of spino-pelvic alignment, especially for cases with severe osteoporosis.

Correlation between Degenerative Thoracolumbar Kyphosis and Lumbar Posterior Muscle

The relationship between spinal alignment, particularly degenerative thoracolumbar kyphosis (DTLK) combined with lumbar spine stenosis (LSS), and paraspinal muscle content remains underexplored. This study aimed to elucidate the characteristics of paraspinal muscle distribution in DTLK patients and its association with lumbar lordosis (LL) and body mass index (BMI).

METHODS

A case-control study was conducted comparing 126 patients with DTLK and LSS against 87 control patients. The lumbar crossing indentation value (LCIV) was introduced as a novel measurement for paraspinal muscle content, and its relationship with thoracolumbar kyphosis (TLK), BMI, and LL was assessed.

RESULTS

LCIV in DTLK patients was found to be lower than in the control group, with a progressive increase from the upper to lower lumbar spine. In the control group, paraspinal muscle content was observed to increase with age and BMI, and LCIV was higher in males. However, the DTLK group showed no gender difference. LCIV in the DTLK group was more pronounced in patients with increased LL. The degree of TLK was not influenced by BMI but was associated with the content of the paravertebral muscle.

CONCLUSIONS

Paraspinal muscle content, as measured by LCIV, is significantly associated with DTLK and LSS. The study emphasizes the importance of considering paraspinal muscle health in DTLK patients and offers valuable insights for diagnosis and therapeutic interventions.