This study demonstrated that patients with DLS enjoyed significant improvement in pain, physical function and deformity after long-level fusion, which was similar to previous studies. Patients with high levels of disability due to sagittal imbalance or spinal stenosis had been demonstrated to experience substantial benefit from total lumbar arthrodesis surgery as compared with nonoperative treatment with respect to reductions in leg and back pain and improvements in physical function[21, 14, 22–25]. However, despited the benefits of correction surgery, extensive spinal fusion also resulted in limited flexibility and to some extent impaired ADL, especially for elderly patients[13].
Stiffness, liked pain, was to some extent a subjective complaint. Although it was possible to measure actual range of motion using radiography[10] or other motion tracking techniques, such approaches did not necessarily informed us of patients’ perceptions of their flexibility, and more specifically of any effects of stiffness on their everyday functional abilities. A self-reported questionnaire such as the LSDI remained the best clinical tool for such an assessment[26].
Previous studies revealed that elder and female patients might be more susceptible to the development of DLS in Chinese Han population[1]. Elderly female in China might face more need for household chores, rather than self-driving, and compared with Korean population, we were also different from their floor-living lifestyle without the use of a bed or a chair. Given the above states, we designed C-LSDI by modifying LSDI and K-LSDI. In this study group of 129 Chinese adult lumbar arthrodesis patients, C-LSDI demonstrated excellent internal consistency and retest reliability compared with LSDI and K-LSDI, Several shortcomings must be considered when interpreting the data, in order to solve the matter of linguistic discrepancies, we translated LSDI and K-LSDI into Chinese, which might introduce bias as data collecting.
Our data showed that increased length of lumbar fusions seemed to increase the stiffness that impaired their ability to wash lower body, perform perineal hygiene after toileting, clean floor, get out of chair, get out of bed and get out of car, and of these disabilities, some patients had significant difficulty in doing perineal self-care functions because of limited range of motion after extended fusion. Bafus et al[6] observed increased difficulties with perineal care compared with their preoperative functional ability were reported by five of the14 patients (36%) having thoracolumbar fusions to L5 or to the sacrum. The result might indicated activities, the higher requirement for flexibility, the more vulnerable.
Another issue was the potential differences in impact of stiffness on ADL after instrumented total lumbar fusions to S1; specifically between patients with UIV within the upper thoracic (UT) versus the thoracolumbar (TL) region. Sciubba et al[14] defined cohort based on the UIV as UT (T1–T6) or TL (T9–L1), and found UT had greater impairment in performing hygiene after toileting. Choi et al[16] categorized patients into 2 group based on UIV, group 1 was above T10 of UIV, group 2 was L1 or L2, and observed group 1 showed higher score compared to group 2 except for question 11(sexual intercourse) in K-LSDI. Interestingly, while patients fused to the upper thoracic spine reported higher mean C-LSDI scores than patients with thoracolumbar stopping points, this did not reach statistical significance in our study. There might be structural or radiographic aspects of patients’ preoperative deformity which lead surgeon to choose upper thoracic versus thoracolumbar endpoints, but we were unable to assess this question in the current analysis. The functional significance of isolated L5-S1 motion still was not completely defined. Given the relatively small sample size, our study did not allow meaningful statistical comparisons, which was similar with previous study, Bafus et al[6] found that the incidence of perineal care difficulties was similar between patients having fusion to L5 and patients having fusion to the sacrum, maintenance of L5-S1 segmental motion did not seem to reduce occurrence of perineal care problems.
In a cohort of patients with an average of 10 motion segments fused, Wilk et al[27] used a tool of computerized movement analysis and found that compared to normal subjects and unfused patients, patients who had lumbar fusions extending to L3 or L4 had 36% less total lumbar motion (P < 0.05). However, Winter et al[28] observed that as the distal level of fusion moved caudally from T12 to L4, there was no significant change in functional spinal motion until the construct extended to L4. The above discrepancy indicated the difference between instrument-assisted methods and patient-reported outcome tools.
Data collection from 129 patients with DLS after long-level fusion, Patients were satisfied with the arthrodesis procedure, which was similar to previous study. Hart et al[29] showed overall among the entire cohort, 46% (27/59) of patients indicated that they experienced significant limitations in daily activity due to back stiffness, however, a large majority of patients indicated that they would undergo the same procedure again (97%, 55/57) and thought that any increase in stiffness from the surgery was an acceptable trade-off for overall functional improvement (91%, 52/57).
Although these results demonstrated sufficiently strong validity and reliability of the C-LSDI to support its use in the clinical outcome research, prospective application of the tool was needed to establish whether reported functional limitations were truly a result of the arthrodesis procedure. The data presented here could not be interpreted as showing that increased limitations were caused by the fusion because this was a retrospective cohort. The association between pain and spinal stiffness was
complex[30, 15], it was possible that patients’ answers regarding the functional domains of C-LSDI might be affected by issues other than lumbar stiffness, such as low back pain or hip and knee pathology[15]. Rather, the intent of this study was to establish the validity and psychometric properties of the C-LSDI. Further work to assess the minimum clinically important differences in C-LSDI scores as well as the relative importance of the C-LSDI to patients in comparison with the current pain and deformity-related outcome will also be helpful to address patient questions regarding these potential impacts from surgery[31].
One limitation of our study was that we had not made measurements of our patients’ actual lumbar range of motion to establish a true ‘‘gold standard.’’ However, prior work had established that the LSDI did indeed correlate to radiographic measurements of lumbar mobility[13]. Despite this, the study had certain advantages. This study expanded on prior work demonstrating the validity and utility of the C-LSDI in assessing stiffness impacts among Chinese patients, and this study also focuses on a single diagnostic and surgical treatment category, i.e., patients with DLS underwent long-level fusion. These data might enhance understanding of functional outcome measurements related to spinal stiffness in patients with DLS before arthrodesis, and might allow for more informed preoperative counseling to patients indicated for such surgical interventions.