Pain and functional disability after lumbar microdiscectomy and their correlations with gender, depression and recovery expectations

Background/Aim. Among the various factors that after lumbar microdiscectomy
 can influence on continued postoperative back pain and/or leg pain and
 functional disability are gender, depression and pessimism. The aim of this
 study was to determine the correlations between these factors. Methods. The
 research was conducted after microdiscectomy on 198 patients (95 men and 103
 women), with mean age 50.20 ? 10.26 years. For examinations were used the
 following questionnaires: for assessment of pain and its intensity and
 character - PainDETECT Test; for functional disability - Oswestry Low Back
 Pain Disability Questionnaire; for the presence and degree of depression -
 Beck Depression Inventory II; and questionnaire for the assessment of
 personal expectations (pessimistic / optimistic) about the treatment
 results. These assessments were carried out after microdiscectomy in the
 terms: just before rehabilitation treatment, one month later and then 3 and
 6 months after microdiscectomy. Results. On the pain and functional
 disability significant negative influences had depression (p<0.01) and
 pessimism (p<0.01). The subjective sensation of pain was significant higher
 in women than in men (p<0.01), while men had a greater degree of functional
 disability (p<0.01) than women. Conclusion. Pain and functional disability
 of the patients after lumbar microdiscectomy are significantly
 interconnected with gender, depression and pessimism. The sensation of the
 pain was higher in women, while men had a greater degree of functional
 disability. Globally, intensity of pain and functional disability were
 significantly greater in patients with a higher degree of depression and
 pessimism and by registering mentioned factors it is possible to predict the
 postoperative results.


Introduction
Microdiscectomy is one of the modern surgical methods for the treatment of low back pain (LBP) and radiculopathy, caused by a herniated intervertebral lumbar disc.
Continued postoperative back pain and/or leg pain, after lumbar decompression back surgery interventions is commonly called failed back surgery syndrome (FBSS), but there are also other terms for the same disorder such as postlumbar surgery syndrome, failed back syndrome, postoperative persistent syndrome, etc. [1,2]. Patients with FBSS describe persistent back, back/leg or leg pain, with functional insufficiency, with or without sciatica, in 10-40% cases after all spinal surgeries [3,4,5]. FBSS is a chronic disorder that has many impacts on the patients, their disability and quality of life and health care systems. FBSS can be caused by various mechanical, biological, psychological and social factors [3,4]. They were the subject of a number investigations which often confirmed the mutual interconnectivity of these factors. Among these factors, Bordoni B. and Epker J. [3,5] found that psychosocial factors such as depression, poor coping, anxiety, somatization, and hypochondriasis have been associated with the development of FBSS.
Also other authors confirmed that intense and long-lasting pain, particularly neuropathic pain, can cause functional disability associated with various psychological disorders: fear, anxiety, depression, pessimism, fear / avoidance beliefs of physical activity and work and quality of life, as well as the social problems [6 -11].
FBSS may be associated with severe pain, disability and higher depression scores.
Because this group of patients should be subjected to a clinical examination and evaluated psychiatrically and treated by using a multidisciplinary approach, containing surgical interventions, rehabilitation and and if necessary psychotherapy [4,5,8].
Among other risk factors for FBSS and poor recovery is also male gender, which may be associated with heavy physical work and more intensive smoking in this population [10].
Using the appropriate questionnaires and registering mentioned factors, it is possible to predict the functional recovery and if necessary to implement on time additional diagnostic and therapeutic procedures to improve the postoperative results [11].
The aim of our study was to detect in our patients after lumbar microdiscectomy the presence of FBSS and functional disability and their association with gender, depression and negative attitudes and beliefs, i.e. pessimism of patients about their own recovery.

Methods
The research was conducted on 198 patients (95 men and 103 women), of various professions and mean age 50.20 ± 10.26 years (range 29-69 years). The study involved patients after surgical treatment of disc herniation by lumbar microdiscectomy, who were These assessments were carried out after microdiscectomy: just before the rehabilitation treatment, one month later and then 3 and 6 months after microdiscectomy.
In statistical analysis as indicators of basic data were used arithmetic mean, median, mode, mode frequency, minimum and maximum values, standard deviation and confidence interval. In addition to standard statistical methods and Student's test were used techniques of mixed model ANOVA with the use of software package STATISTICS 12, serial number AXA 302C271408AR-B. Values of p < 0.05 were regarded as statistically significant, and p < 0.01 as statistically highly significant.

Results
The number, gender and age of of the examined patients are shown in Table 1. Table 1.
The mean age of examined persons was 50.2 years, without significant differences between men and women.

The current pain intensity in the monitored periods
Current intensities of pain expressed by Numeric pain rating scale (NPRS) with range 0 to 10, estimated at the start, after 1, 3 and 6 months, are shown in Table 2. Table 2.
The decrease of pain intensity during the observed period, in comparison with the value at the start, was highly significant (p<0.01), as can be seen in Table 2.
The presence of pain and its neuropathic component were evaluated by Pain DETECT Test. According to the score results the patients with pain were divided into three categories:

A neuropathic pain component is unlikely (probability less than 15%)
2. Result is ambiguous, however a neuropathic pain component can be present

A neuropathic pain component is likely (probability greater than 90%).
The results during the examined period are shown in Table 3. Table 3.
After the relocation of patients from the Clinic for neurosurgery to the Medical Rehabilitation Clinic (0. month) all 198 (100%) patients had the pain. Among them 125 (63.1%) patients were with ambiguous result (possible neuropathic pain) and 73 (36.9%) with likely neuropathic pain (probability greater than 90%). After three months the pain had 15 (7.6%) patients, of whom only 1 (6.7%) was with neuropathic pain. After 6 months only 8 (4,0%) patients had pain, but none of them had neuropathic pain. These results can be seen on the table 3.

Functional disability during examined period
The values of functional disability expressed by Oswestry disability index (ODI) are shown in Table 4. Table 4.
Mean ODI values during testing period decreased after microdiscectomy highly significant (p <0.01) in comparison with the value at the start (Table 4).

Depression during examined period
Levels of the depression were evaluated by using Beck Depression Inventory and their values during the study period are shown in Table 5. Over time, the numbers and percentages of patients with low, moderate and high level of depression were changed as can be seen in Table 6. Table 6.
During testing period the numbers of patients with moderate and high levels of depression gradually decreased ( Table 6).

The intensity of the pain in men and women
Current pain intensity, expressed by a Numeric pain rating scale (NPRS), was registered among women and men at the beginning of physical therapy (0. month), then after 1 month and 3 and 6 months after microdiscectomy. The results are shown in Figure 1. Global reduction of pain intensity in the 1st, 3rd and 6th month was very significant compared to the initial state, but the pain all the time was more intensive in women than in men.

Functional disability in men and women
Results of Oswestry Disability Questionnaire expressed as Oswestry Disability Index (ODI) for men and women during the examined period are shown in the Figure 2. Global ODI values over time significantly decreased, but all ODI values during the monitored period were lower in women than in men, as it can be seen in Figure 2.  The greatest intensity of pain in all periods of examination had patients with clinically severe depression, lower pain had people with moderate depression, while pain intensity was the lowest among those who had mild i.e. minimal depression (Figure 3). Anyway, globally in all groups, the intensity of pain during the study period was significantly reduced (p <0.01).

Depression and functional disability
The impact of depression on functional disability is shown in Figure 4. The degree of depression was estimated with Beck Depression Inventory and the degree of functional disability by using the Oswestry disability questionnaire index (ODI). The results in Figure 4 show that the highest degree of functional disability (ODI) had patients with clinically severe depression, lower degree of disability had those with moderate depression, and the lowest disability showed patients who were practically without depression. The difference of these results was statistically highly significant (p <0.01).

The patient's expectations of the recovery (optimism / pessimism) and the intensity of pain
According to the expectations of patients in relation to their own recovery after a surgical procedure and performed physical therapy, patients were classified into groups in which then, during the examined period, was estimated the intensity of the current pain. This classification into groups was carried out according to the following patient's own expectations of recovery: totally, mainly, partly, a little, I don't know. This classification also showed the degree of optimism or pessimism in the investigated patients.
The link between expectations, ie. the degree of optimism and pessimism of the patients about their recovery, with the pain intensity after operation, in the monitored period, are shown in Figure 5. As can be seen in Figure 5, during the postoperative monitoring, the lowest pain intensity had patients who were optimistically oriented and who expected that treatment will be successful and that they will be totally recovered. On the other side, greater intensity of pain had the groups of patients who expected partially or just a little improvement of their own health and functional status and patients whose expectations were undetermined.

Expectations regarding the recovery and the degree of disability of patients
The link of expectations, ie. the degree of optimism and pessimism of the patients about their recovery, with the ability / disability estimated by Oswestry disability questionnaire index (ODI) after operation, in the monitored period, are shown in Figure 6. During the postoperative monitoring the lowest ODI had patients who were optimistically oriented and who expected that treatment will be successful ie. that they will be totally recovered. On the other side, the greatest disability had the groups of patients who expected partially or just a little improvement of their own health and functional status ( Figure 6).
Chronic pain has negative impact on the psychological and emotional state, functionality, and quality of life [12][13][14]. On the other hand, negative emotions and psychological disorders have reverse effects and can increase the intensity of pain perceptions and disability. Mentioned factors in chronic LBP are essentially mutually widely connected and have an interactive relationship with each other. Therefore, these factors should be registered in the diagnostic and included in the treatment procedures because it will enable better success in treatment and faster functional recovery [12][13][14].
According to published data, patients describe FBSS with uncontrolled persistent back, back/leg or leg pain, with or without sciatica, with a wide incidence ranges from 10-40% [3,4,5]. In our study in first month of examinations 39 (19.7%) patients had the pain .
For assessing the intensity and character of pain in our study was used PainDETECT questionnaire, simple and in practice proved as a valuable [15]. The results of this test have shown that during the follow-up period, the number of patients with pain and the number of those with neuropathic or potentially neuropathic pain significantly decreased. These reductions of pain are useful because people with neuropathic pain show higher ratings of pain intensity, depression, anxiety and functional disability [15,16].
In our patients the intensity of the pain and functional disability were in all subjects during the test period significantly reduced in comparison with baseline values. However, women had all the time a higher pain intensity than men, while men had significant greater degree of functional disability. This could be explained by the presence of greater emotional sensitivity in women and higher mechanical and physical workload of the spine in men due to the nature of their job.
Also, Shi J. et al. found that FBSS was more common in men than in women [10]. They concluded that besides hard physical work also smoking and duration of preoperative symptoms significantly influenced clinical outcome [10].
Among the various psychological factors negative influence on postoperative recovery may have depression and pessimism [17 -20]. Also, similarly negative influence may have anxiety, fear and avoidance beliefs [18,19]. This was also the theme in one of our research.
Most of the researches emphasizes the psychological factors and their impact on pain, postoperative recovery and functionality after microdiscectomy. However, there are also reversed attitudes that the reduction of pain after microdisectomy is the primary and the most important factor which decreases the negative psychological attitudes [19,20]. For example microdiscectomy and decompression of the nerve reduce the pain-associated depression, and improve mental well-being and functional status in patients with herniated lumbar disc [19,20].
Such results were also in the examination of our patients and with the reduction of pain intensity also decreased the level of depression and functional disability. In conclusion it may be noted that the most acceptable attitude could be that all of the above mentioned factors are in mutual reciprocal connection and that all together have an influence on recovery and functionality of patients after microdiscectomy. On these conclusions also suggest the results of our examination since the reduction of pain and improvement of psychological state and functionality of the patients during the examined period were parallel. As the treatment of these conditions is complicated, it requires a multidisciplinary approach in many cases.
The mentioned approaches and procedures deserve attention, as well as their application in the future in our region in patients who will undergo a microdiscectomy for the treatment of low back pain. It will be the goal of our future activities.

Conclusion
The intensity of pain and functional disability are significantly associated with depression and pessimism in the patients after lumbar microdiscectomy. The sensation of pain was higher in women, while men had a greater degree of functional disability.
Registering mentioned factors it is possible to predict the recovery of the patients after lumbar microdiscectomy.