QUALITY OF LIFE ANALYSIS ON PATIENTS AFTER ARTHROPLASTY OR LUMBAR ARTHRODESIS

ABSTRACT Objective: To perform a retrospective analysis of patients with degenerative disc disease of the lumbar spine undergoing arthrodesis or lumbar arthroplasty in terms of functional capacity and quality of life. Methods: Retrospective observational study analyzing the medical records of patients undergoing arthrodesis or lumbar arthroplasty, followed-up at an outpatient clinic from 2018 to 2020. Patient characteristics were evaluated; the quality of life through the results of the Short Form 36 Health Survey Questionnaire (SF-36) and the functional capacity using the Oswestry Disability Index (ODI) in the pre-surgical and post-surgical periods (6 months, 1 and 2 years). The criterion to establish statistical significance was p≤0.05. Results: Sixty-one patients were evaluated. After the surgical interventions, the individuals migrated from the classification of invalid (61.4%-64.6%) to minimal/moderate disability (17.7%-25.6%). There was a decline in ODI scores over time of follow-up (p≤0.001) as well as in SF-36 values (p≤0.001) for all surgical techniques. In this regard, evaluating the difference in means revealed the better performance of lumbar arthroplasty (p≤0.001). Conclusion: The data suggest that lumbar arthroplasty offers greater benefits to patients regarding functional capacity and quality of life. Level of Evidence III; Retrospective, descriptive, observational study.


INTRODUCTION
Low back pain (LBP) is a symptom of discomfort or pain located between the costal margin and the lower gluteal fold area and may or may not be associated with irradiation to the lower limb, which occurs in up to 60% of cases. 1,2tudies show that low back pain is the most common occupational problem in the world, with an incidence of 139 per 100,000 people per year among the general population of the United States.Low back pain has an important socioeconomic impact.4][5] In Australia, the total cost of managing low back pain was estimated to be $9 billion in 2001.7][8] In the country, the prevalence of low back pain exceeds 50% of the adult population, and chronic cases represent 4.2% and 14.7% of the population.In addition, low back pain is the leading reason for leave from work. 9][12] Initially, the treatment is conservative with bed rest for 2 to 3 days, physical exercise with the restoration of strength, and flexibility, postural education, physical therapy with strengthening and stretching of the paravertebral muscles, use of ultrasound, electrical stimulation, and massage.In pharmacological treatment, non-steroidal anti-inflammatory drugs (NSAIDs) are the first-line agents.Selective transforaminal steroid injections can produce symptomatic relief in many patients and are offered to those who have failed non-invasive measures but are not interested in or are not good candidates for surgical treatment; all are useful in short-term symptomatic relief of low back pain. 13The absolute indication for surgical treatment is progressive neurological deficit and intractable pain.However, patients who present radiological findings of compressive pathology concordant with clinical signs and symptoms and refractory to conservative treatment are considered ideal candidates for surgical approaches.Among the surgical options are segment fusion, associated with bone grafting, to promote the affected segment's arthrodesis.Lumbar arthrodesis is accepted as the gold standard in the surgical treatment of DDD. 14,15Arthrodesis is expected to block motion and instability at symptomatic levels, reducing or eliminating pain in the addressed segment. 16n this regard, there are a few surgical approaches for performing lumbar arthrodesis, among which are the Posterior Lumbar Intervertebral Fusion (TLIF) technique and the Anterior Lumbar Intervertebral Fusion (ALIF).In TLIF, the exposure of the lumbar spine extends laterally to the transverse processes.For this, it is necessary to retract all adjacent soft tissues, 17 and implant a bone-filled Cage with pedicle screw instrumentation.18 With ALIF, access to the lumbar spine is via the abdominal route, avoiding trauma to the posterior musculature, which can reduce pain and postoperative limitations.19 Inherently, arthrodesis produces abnormal conditions in the spine biomechanics that can cause overloading at asymptomatic levels, leading to an increased rate of degeneration of adjacent discs.20 Furthermore, complications with screw placement, failure of synthesis material, and pseudoarthrosis are conditions observed in post-surgical follow-up and have received scrutiny by surgeons over time, driving the development of alternative methods to arthrodesis.21,22 As an option, lumbar arthroplasty, which is technically defined as an artificial total intervertebral disc replacement (TDR-Total Disc Replacement), is used judiciously in the surgical treatment of lumbar DDD in eligible patients, helping to restore and preserve motion in the affected segment and protect the adjacent levels from unphysiological overload.Thus, recent studies show a reduced incidence of degenerative disc disease at the adjacent level.23,24 Recent clinical studies using lumbar arthroplasty have shown sustained clinical and radiographic results over five years, with superior clinical outcomes compared to lumbar arthrodesis.25,26 Thus, arthroplasty has been increasingly used as an alternative surgical treatment for degenerative disc disease in eligible patients.The purpose of this study was to perform a retrospective analysis of patients with DDD of the lumbar spine who underwent single-level lumbar arthrodesis or arthroplasty in terms of functional capacity and quality of life.

Study type and location
A retrospective observational study of analysis of information collected from medical records from 2018 to 2020, of patients followed up as outpatients in tertiary care services in São Paulo state.

Eligibility Criteria
Patients over 18 years of age with DDD, refractory to conservative treatment, and undergoing lumbar arthrodesis or single-level lumbar arthroplasty.For adequacy and standardization of the groups, the eligible patients had a Pfirrmann classification -IV, associated with degenerative discopathy, with the presence of bulging, protrusion, or presence of extruded herniation with pain and irradiation to lower limbs, with outpatient follow-up of at least 06 months, showing the full capacity to understand the research instruments.In contrast, the exclusion criteria were data from patients' medical records with loss of follow-up or less than 06 months of outpatient follow-up.

Data Collection and Research Instrument
A database examiner performed data collection from information contained in the medical records using a form with the patient's characteristics, the Short Form 36 Health Survey Questionnaire (SF-36), and the Oswestry Disability Index (ODI) in the preoperative and postoperative periods (6 months, 1, and 2 years).
The SF-36 is used to assess general health and quality of life that contains 36 items measured by eight domains: Functional Capacity (FC), Limitation by Physical Aspects (LAF), Pain (DOR), General Health Status (GHS), Vitality (VIT), Social Aspects (AS), Limitation by Emotional Aspects (LAE) and Mental Health (SM).The number of response options for each domain ranges from three to six, the calculations of which produce scores of up to 100 points and are considered reliable instruments.The evaluation of the scores advocates that higher scores are related to better health status. 27he ODI is an instrument for functional assessment of the lumbar spine, consisting of 10 items representing different aspects of health, such as pain intensity, physical functioning, impacts on sleep, and social activities.The ODI total score is presented as a percentage, in which lower values are attributed to better functioning. 28The interpretation of the findings is presented as follows: minimal disability (0 -20%), moderate disability (21 -40%), severe disability (41 -60%), disability (61 -80%), bedridden or overestimating their symptoms (81 -100%). 29

Study Variables and Statistical Analysis
The clinical and demographic characteristics of the patients (gender, age, education, lifestyle habits, and comorbidities) were analyzed.ODI findings and quality of life by SF-36 established functional capacity.
After collecting the data on a specific form, they were tabulated in a Microsoft Office Excel 2013 spreadsheet.The Statistical Package for the Social Sciences 25.0 statistical package was used to conduct the relevant statistical analyses.In this aspect, we evaluated the means and standard deviation for the ODI and SF-36 scores and the normality test of the data distribution by the Shapiro-Wilk method.Measures of statistical significance in terms of values and p≤0.05   at all observation times, including for the evaluation of paired samples, were obtained using Student's t-test for normally distributed variables.Given the non-normality of the distribution, the Wilcoxon test was used.The magnitude of the difference in means between the groups was checked by Cohen's test (d), and values ≥0.8 were considered large-magnitude effects.

Ethical Aspects
The research project was submitted to the Ethics and Research Committee of the University Center of the ABC Medical School and approved under the CAAE registration: 54889222.4.0000.0082.

RESULTS
The study population consisted of 61 patients, of whom 14 underwent lumbar arthroplasty, 22 Anterior Lumbar Intervertebral Fusion (ALIF) with Cage Stand -Alone, and 25 Posterior Lumbar Interbody Fusion (TLIF) (Table 1).Regarding comorbidities, the ALIF group reported the highest occurrence of diabetes mellitus and associated systemic arterial hypertension (27.3%).Smoking was also most commonly reported by this group (18.2%).On the other hand, the group with the fewest comorbidities was the TLIF group, in which 64.0% of the patients denied having any disease.
It was noticed that the patients migrated from the invalid classification (61.4%-64.6%) to minimal/moderate disability (17.7%-25.6%)(Figure 1).Furthermore, the analysis of the results for the techniques evaluated showed a consistent decrease in the ODI values over the follow-up time, of which lumbar arthroplasty had the greatest impact of decrease, with statistical significance (p<0.001).
The evaluation of the comparison of the ODI values by the paired-samples technique is shown in Table 2. Again, you can see the differences in the averages and the maintenance of results over time, with better performance for the lumbar arthroplasty technique.
Regarding the SF-36 findings, an increasing mean was observed for the ALIF technique for the investigated domains, except EGS and VIT.More expressive findings were identified for LAF.Statistical significance was observed with values of p<0.001.(Figure 2) For the TLIF technique, it was observed that the mean was increasing for all SF-36 domains, especially for the AS (Figure 3).However, after analyzing the comparison of means, it was noticed that the increment for most domains was lower than that of the other surgical techniques investigated (Table 3).Student's t-test (p<0.001)observed the statistical significance of the correlations.
Regarding the SF-36 results for the lumbar arthroplasty technique, increasing mean values were identified for most of the investigated domains since there was a slight reduction in the LAE and VIT values in the 2-year postoperative period.The most expressive findings were for LAF, the domain with the greatest increase observed among all techniques when comparing the pre-and postoperative periods (0.0 -85.7) (Figure 4).These findings proved to be statistically significant (p<0.001).
The stratified analysis of the SF-36 by surgical technique showed that lumbar arthroplasty presented better results after 02 years of follow-up for LAF, DOR, EGS, and AS (p<0.001).Considering the magnitude of the results for the 08 domains of the SF-36, this surgical technique was the one that presented the greatest benefit for the patients.(Table 2)

DISCUSSION
In this study, 61 patients with disability classification for functional capacity were evaluated and divided into three groups: those who underwent arthrodesis using the ALIF technique with Stand-Alone Cage, those who underwent arthrodesis using the TLIF technique, and those who underwent lumbar arthroplasty with total intervertebral disc replacement.The retrospective evaluation of three postoperative periods (6 months, one year, and two years) showed significant clinical improvement regardless of the surgical technique used; however, the functional capacity and quality of life results were superior in the lumbar arthroplasty group.
Regarding functional capacity, the ODI values for this surgical technique showed a constant reduction in scores over the follow-up period, culminating in an improvement of 47.1 points at two years postoperatively, that is, minimal disability in terms of clinical classification at the end of the follow-up period.Our findings were superior to those of the study by Scott-Young and colleagues, 30 in which the ODI score showed an improvement of 31.7 points.The literature reveals that scores above 18.8 are considered a substantial benefit for patients with high levels of disability preoperatively. 31he specialized literature has suggested the superiority of arthroplasty over intervertebral fusion surgical techniques, 32 data corroborated by our findings.A recent meta-analysis study concluded that after three years of follow-up, the mean percentages for ODI scores were lower among patients who underwent arthroplasty (22.8 points)  than patients in the arthrodesis group (27.6 points). 33he lumbar fusion technique is very well established for treating degenerative disc disease.However, despite the satisfactory clinical results, the change in the original biomechanics of the spine proposed by the technique with consequent immobility caused by the fused segments generates an overload on the adjacent segments and may lead to disc degeneration. 34In clinical terms, this particularity may culminate in negative repercussions for patients, including joint stress, impact on neural structures, and tension on the paravertebral muscles, which may translate into pain, limitation of movement, and loss of quality of life over time.In this respect, arthroplasty emerges as an alternative to arthrodesis by replacing the intervertebral disc with the maintenance of spinal motion and harmonic distribution of the axial load. 35mong our patients, the SF-36 results showed gains mainly in limitation by physical aspect.This finding becomes particularly important considering that our population was classified as economically active.Reduced physical activity substantially influences the maintenance of independence and resumption of work activities, with positive effects on the economy.Low back pain is known as the main cause of absence from work, reverberating in the social security dynamics by absenteeism and the demand for specialized health services. 9he positive findings for SF-36 in our study agree with the results of previous investigations conducted by Joelson, Sigmundsson, and Karlsson 36 for arthrodesis and Scott-Young 37 for arthroplasty, with the maintenance of post-surgical outcomes.We emphasize that our study compared patients who underwent different surgical techniques.Still, all had their surgery performed by the same professional, who used standardized techniques and did not participate in data collection and analysis, thus having no influence on the results presented here.
Regarding the study's limitations, we highlight its retrospective nature, whose inferences were made based on data collected by third parties.In addition, the sample size was relatively small, and patients were not randomly assigned to each surgical technique group.In this respect, we emphasize that the election of patients for a particular technique was made carefully based on well-established clinical criteria.Furthermore, the use of different outcome instruments, both with positive results, and the conduct of robust statistical analyses appropriate for our sample allowed us to affirm our findings.

CONCLUSION
The surgical techniques evaluated had a positive and sustained impact over two years of postoperative follow-up, improving patients' functional capacity and quality of life, of which lumbar arthroplasty had superior performance.
All authors declare no potential conflict of interest related to this article.

CONTRIBUTIONS OF THE AUTHORS:
Each author contributed individually and significantly to the development of this article.SGM: design of the paper; data analysis and interpretation, writing of the manuscript; RLMR: a review of the intellectual concept of the paper and final approval of the manuscript version to be published; LFA: data analysis and revision of the paper; CAEM: substantial contribution in the design of the paper and critical review of its intellectual content.

Figure 1 .
Figure 1.ODI values for the follow-up times according to surgical techniques.

Figure 2 .
Figure 2. SF-36 values for the follow-up times according to the ALIF surgical technique.

Figure 3 .
Figure 3. SF-36 values for the follow-up times according to the TLIF surgical technique.

Figure 4 .
Figure 4. SF-36 values for the follow-up times according to surgical technique Lumbar Arthroplasty.

Table 1 .
Sociodemographic characterization of the study population according to the surgical techniques instituted.

Table 2 .
Comparison of mean difference for ODI values for the follow-up times according to surgical techniques.

Table 3 .
Stratified analysis of the SF-36 for the follow-up periods according to surgical techniques.