Efficacy of Respiratory Training in Relieving Postoperative Pain in Patients with Spinal Nerve Root Entrapment Syndrome.

Background: Breathing exercise can help patients with dyspnea to change the wrong breathing pattern, improve the degree of freedom of respiratory muscles, increase alveolar ventilation, promote breathing, and relieve the symptoms of dyspnea patients. Therefore, this study is aimed at investigating the role of breathing training in alleviating postoperative pain in patients with spinal nerve root entrapment syndrome. Objective: To explore the effect of respiratory training in relieving postoperative pain in patients with spinal nerve root entrapment syndrome.
Methods: Fifty-eight patients with spinal nerve root entrapment syndrome treated in our hospital from May 2020 to May 2021 were analyzed retrospectively. The patients were randomly divided into a control group (n = 29) and an observation group (n = 29). The control group was given routine postoperative pain nursing, and the observation group was given respiratory training on the basis of the control group. The scores of visual analogue scale (VAS), self-rating anxiety scale (SAS), Oswestry dysfunction index questionnaire (ODI), the dosage of postoperative analgesics, and the time of first out-of-bed activity were recorded before pain nursing intervention and 3 days and 7 days after intervention.
Results: The VAS, SAS, and ODI scores of the observation group after 3 d and 7 d of intervention were lower than those of the control group. Compared with the same group, the scores of VAS, SAS, and ODI after 3 d and 7 d of intervention were lower than those before intervention, and those after 7 d of intervention were lower than those after 3 d of intervention (P < 0.05). The dosage of postoperative analgesics and the time of first out-of-bed activity in the observation group were lower than those in the control group (P < 0.05).
Conclusion: Respiratory training can effectively relieve postoperative pain, reduce anxiety, and improve spinal function in patients with spinal nerve root entrapment syndrome, which is beneficial to the prognosis of patients and is worthy of promotion.

1. Introduction

Spinal nerve root entrapment syndrome (SNRES) is mainly caused by mechanical entrapment of nerve roots due to complications caused by diseases such as disc herniation and spinal canal stenosis [1]. Minimally invasive decompression surgery is mainly used to alleviate the disease. The spinal nerve roots originate in the spinal cord and are the initial part of the peripheral nerves of the limb. Decompression surgery is more pronounced for pain caused by mechanical damage to the nerve, and patients need bed rest after surgery. There is some risk of pulmonary infection, causing coughing, inflammation, and other pain, which seriously affect the postoperative recovery of patients [2]. Respiratory function training is through training, so that patients can use all inspiratory muscles (diaphragm, sternocleidomastoid muscle, external intercostal muscle, and scalenus muscle) and expiratory muscle (abdominal muscle, intercostal muscle) to actively participate in contraction, in order to achieve the purpose of increasing the strength and endurance of respiratory muscles [3]. Breathing exercise can help patients with dyspnea change wrong breathing patterns, improve the freedom of respiratory muscles, increase alveolar ventilation, promote breathing, and alleviate the symptoms of patients with dyspnea [4]. The advantage of breathing training method is that it can alleviate the dyspnea of patients under the premise of noninvasive and can be better accepted by patients [5]. Respiratory training method has been widely used in clinical prevention and treatment of respiratory diseases to improve the lung function of patients and alleviate the symptoms of dyspnea. Some studies have shown that breathing training can significantly reduce the symptoms of dyspnea in patients with chronic obstructive pulmonary disease (COPD) and prolong the survival time [6]. Respiratory training for patients undergoing abdominal surgery before and after surgery can reduce the risk of complications such as pulmonary infection, thus shortening the length of stay of patients [7]. In addition, previous research has shown that breathing training can alleviate the symptoms of dyspnea and prolong survival time [8]. Respiratory training can relieve pain by guiding patients to consciously prolong the time of spontaneous breathing and controlling abdominal ups and downs to carry out regular breathing exercise [9, 10]. Therefore, the purpose of this study was to explore the effect of respiratory training in relieving postoperative pain in patients with spinal nerve root entrapment syndrome.

2. Materials and Methods

2.1. General Information

Fifty-eight patients with spinal root entrapment syndrome treated in our hospital from May 2020 to May 2021 were analyzed retrospectively. The patients were randomly divided into a control group (n = 29) and an observation group (n = 29). There was no significant difference in general data between the two groups (P > 0.05, Table 1).

Table 1

General information (n (%), ).

Group	Control group (n =29)	Observation group (n =29)	t/χ2	P
Gender (male/female)	21/8	20/9	0.083	0.773
Age (years)	41.86 ± 2.54	42.17 ± 2.68	0.453	0.653
Preoperative course of disease (year)	1.72 ± 0.75	1.69 ± 0.76	0.174	0.863
Type of operation (example)
Minimally invasive passage technique for intervertebral disc herniation	16 (55.2)	17 (58.6)	0.516	0.915
Resection of intraspinal neurilemmoma	3 (10.3)	3 (10.3)
Resection of intraspinal neurofibroma	2 (6.9)	3 (10.3)
Minimally invasive passage technique for spinal canal stenosis	8 (27.6)	6 (20.7)

Inclusion criteria were as follows: (1) the patients with spinal nerve root entrapment syndrome by clinical imaging examination; (2) the patients who underwent intervertebral and spinal canal surgery for the first time at the age of 20-60 years old; (3) loss of consciousness after operation and stable vital signs; and (4) the patients without surgical contraindications.

Exclusion criteria were as follows: (1) the patients with other chronic pain; (2) the patients with other serious lumbar diseases, such as lumbar osteoporosis and fracture; (3) the patients with respiratory diseases; (4) the patients with severe heart, liver, and renal insufficiency; (5) the language communication and expression disorders; (6) patients who lacked complete medical record data; (7) psychiatric patients; (8) pregnant women around 3 months of gestation; and (9) patients with bleeding tendencies and coagulation mechanism dysfunction.

2.2. Methods

The controlled cases were given routine pain nursing. The observation cases were given respiratory training on the basis of routine nursing care in the control group. After the operation, the patients were instructed to do respiratory training and the patients were assisted to take off the pillow in a supine position. The patient's legs were naturally spread apart, shoulder-width apart. The nurse instructed them to take the initiative and inhale slowly through the nose, causing the abdomen to bulge and the diaphragm to sink as far as possible, then stop for 1 to 2 seconds. Exhale with the mouth in an O shape, and exhale slowly to promote upward movement of the diaphragm, assisted by gentle pressure on the abdomen with both hands. Exhale as much as possible, adjusting the breathing ratio to 1 : 2. Slow and lengthen your breathing, with an appropriate breathing rate of 6 : 8 breaths/min and breathing exercises for 20-30 min/time. Do this 3 times a day in the morning before getting up, in the afternoon, and in the evening before going to sleep. In the process of breathing training, the whole-body relaxation is emphasized, and at the same time, patients are accustomed to abdominal breathing during activities.

2.3. Observation Index

The observation indexes were as follows: (1) comparison of postoperative pain between the two groups. The patients in both groups were evaluated with visual analogue scale (VAS) [11] at rest before and 3, and 7 days after the intervention. The Vernier was scaled back to the patient. The patient marked the position that could express the degree of pain. The degree of pain ranged from high to low to 10-0; (2) comparison of postoperative anxiety between the two groups. The postoperative anxiety of the two groups was evaluated with self-rating anxiety scale (SAS) before and 3 and 7 days after the intervention. SAS used 4 grades with a total of 20 items, with a total score of ×1.25. The standard score was normal < 50 points and mild anxiety score of 50-59 points, 60-69 moderate anxiety, and >69 severe anxiety [12]; (3) comparison of postoperative function between the two groups. The pain nursing care of the two groups was evaluated with Oswestry Disability Index questionnaire (ODI) before and 3 days and 7 days after intervention. There were 10 items in ODI [13], and each item was scored 0.5; (4) the dosage of postoperative analgesics and the time of getting out of bed for the first time in both groups. The dosage of postoperative analgesics and the time of getting out of bed for the first time were recorded in both groups.

2.4. Statistical Analysis

All statistical analysis of data in this study was performed using SPSS 24.0 software. The statistical graphics were drawn using GraphPad Prism 8.0. Measurement data conforming to normal distribution were expressed as mean ± standard deviation. The intragroup comparison was performed by paired-sample t-test, and the comparisons between various groups were by independent-samples t-test. P < 0.05 was considered statistically significant. If it was not consistent, it was expressed by the median (lower quartile to upper quartile). Paired-sample nonparametric test was used for intragroup comparison, and independent sample nonparametric test was used for intergroup comparison. The grade data were tested by Fisher accurate method. P < 0.05 was considered statistically significant.

3. Results

3.1. The VAS Scores before Intervention and 3 Days and 7 Days after Intervention Were Compared between the Two Groups

The VAS score of the observation group was lower than that of the control group after 3 and 7 days of intervention. The VAS score of the observation group after 3 and 7 days of intervention was lower than that of before intervention, and that of 7 days after intervention was lower than that of 3 days of intervention (P < 0.05, Table 2).

Table 2

Comparison of VAS scores before intervention and 3 days and 7 days after intervention between the two groups (, points).

Group	Before intervention	After 3 days of intervention	7 days after intervention
Control group (n = 29)	6.22 ± 1.24	5.22 ± 0.74	4.66 ± 0.51
Observation group (n = 29)	6.15 ± 1.31	4.11 ± 0.46	2.62 ± 0.13
t	0.209	6.860	20.873
P	0.835	<0.001	<0.001

3.2. The SAS Scores before Intervention and 3 Days and 7 Days after Intervention Were Compared between the Two Groups

The SAS score of the observation group was lower than that of the control group after 3 and 7 days of intervention. The SAS score of the observation group after 3 and 7 days of intervention was lower than that of before intervention, and that of 7 days after intervention was lower than that of 3 days of intervention (P < 0.05, Table 3).

Table 3

The SAS scores before intervention and 3 days and 7 days after intervention were compared between the two groups (, points).

Group	Before intervention	After 3 days of intervention	7 days after intervention
Control group (n = 29)	58.38 ± 6.48	54.66 ± 5.24	49.14 ± 5.18
Observation group (n = 29)	58.66 ± 6.32	50.48 ± 4.59	42.62 ± 4.27
t	0.167	3.231	5.230
P	0.868	0.002	<0.001

The ODI score of the observation group was lower than that of the control group after 3 and 7 days of intervention. The ODI score of the observation group after 3 and 7 days of intervention was lower than that of before intervention, and that of 7 days after intervention was lower than that of 3 days of intervention (P < 0.05, Table 4).

Table 4

The ODI scores before intervention and 3 days and 7 days after intervention were compared between the two groups (, points).

Group	Before intervention	After 3 days of intervention	7 days after intervention
Control group (n = 29)	31.24 ± 2.85	25.72 ± 2.52	19.86 ± 2.15
Observation group (n = 29)	30.62 ± 2.67	22.52 ± 2.26	15.17 ± 1.62
t	0.855	5.091	9.382
P	0.396	<0.001	<0.001

3.3. Dosage of Postoperative Analgesics and Time to Get Out of Bed for the First Time

The dosage of postoperative analgesics and the time of first out-of-bed activity in the observation group were lower than those in the control group (P < 0.05, Figure 1).

Figure 1

The amount of analgesic drugs used after operation and the time of first out-of-bed activity in the two groups.

4. Discussion

The main clinical manifestations of spinal nerve root entrapment syndrome are nerve root symptoms, which are mostly complications of cervical spondylosis, lumbar spinal canal stenosis, intervertebral foramen stenosis, and intervertebral disc herniation. The concept of spinal nerve root entrapment syndrome was first proposed by Arnoldi et al. in 1976, which was used to cover a series of spinal diseases mainly manifested as nerve root symptoms. This can play a positive role in the diagnosis and surgical treatment of spinal nerve root compression, which has lack of early imaging examination and can only be judged according to clinical symptoms and signs. Subsequently, some diseases causing nerve root entrapment and the imaging evidence of nerve root entrapment were confirmed, and the diagnosis of spinal root entrapment syndrome was rarely used. More diseases such as intervertebral disc herniation, spinal canal stenosis, and cervical spondylitis radiculopathy are used for diagnosis. In recent years, many minimally invasive spinal surgeons have gradually realized that when nerve root mechanical compression is caused by different diseases, trauma is the common clinicopathological manifestation, and remarkable curative effect can be obtained by using the same minimally invasive decompression technique. Based on this, nerve root entrapment syndrome has been paid more and more attention. As the initial part of the peripheral nerve of the limb, the spinal nerve root has the anatomical basis of entrapment in the spinal cord [14]. In the spinal canal, the spinal nerve root is adjacent to some important structures. The posterior longitudinal ligament, vertebral body, and intervertebral disc are located within the anterior and anterolateral of the spinal nerve root; the ligamentum flavum and lamina are located within the posterior and posterolateral. However, the pedicle is located outside. After going out of the intervertebral foramen, the intervertebral disc is in the posterior medial side of the nerve root. There are also corresponding ligaments, muscles, and fascia structures in this area [15]. In the cervical vertebrae, the uncinate joint is located on the inside of the cervical spinal nerve root. When pathological changes occur in structures adjacent to spinal nerve roots, the nerve root may be compressed due to the narrowing of the anatomical space for the nerve root. In the cervical vertebra, when the cervical spinal nerve root passes through the intervertebral foramen, it can be oppressed from the outside by the hypertrophic and hyperplastic facet joint. After getting out of the intervertebral foramen, it can be oppressed medially by the osteophyte on the uncinate joint [16]. In the thoracic vertebrae, the thoracic spinal nerve roots can also be oppressed by structures such as protruded intervertebral discs, showing clinical symptoms such as banding sensation. In the lumbar spine, the lumbar nerve root can be squeezed by protruded intervertebral disc, hypertrophic ligamentum flavum, narrow lateral recess, and intervertebral foramen, resulting in corresponding pathological and clinical changes of nerve root compression [17].

With the deepening of the understanding of spinal diseases and the improvement of modern auxiliary examination techniques, it is possible to accurately locate the compression site of the spinal nerve root and determine what structure the nerve root is compressed by in most cases [18-20]. Therefore, the authors believe that the generalized spinal nerve root entrapment syndrome can be defined as a spinal disease with nerve root symptoms as the main clinical manifestation and imaging examination showing definite spinal nerve root compression. Generalized spinal nerve root entrapment syndrome includes cervical spondylotic radiculopathy, intervertebral disc herniation and lumbar spinal canal stenosis, intervertebral foramen stenosis, and cauda equina syndrome [21]. At the same time, the diagnosis of spinal root entrapment syndrome has pointed out the common characteristics of these spinal diseases and nerve root entrapment, which can deepen the understanding of these diseases [22]. A narrow definition of spinal nerve root entrapment syndrome is as follows: nerve root symptoms as the main clinical manifestation; imaging examination showed a clear spinal nerve root compression. At present, there is no clear diagnostic name of spinal disease. For example, the patients can show clinical symptoms and signs of spinal nerve root compression in clinical practice. The evidence of nerve root compression is clearly observed in imaging examinations. However, no other lesions can be found [23]. Minimally invasive decompression surgery can also be used when mechanical compression of the nerve root is the main clinicopathological manifestation. The aim of treatment is to decompress and relax the mechanically compressed nerve root and to relieve the nerve root pain [24, 25]. However, minimally invasive surgery is an invasive operation, which has a variety of pain symptoms, such as surgical wound, muscle traction, and postoperative abdominal pain.

Several studies have shown that the diaphragm has the dual functions of controlling breathing and trunk stability [26]. The impairment of diaphragm function will increase the risk of low back pain, so correct breathing training can enhance the stability of trunk muscles and the range of motion of the chest [27]. Among them, abdominal breathing training is a commonly used clinical breathing training method. Meanwhile, improving abnormal breathing patterns can increase blood oxygen levels for self-regulation of the body and mind [28]. Breathing training methods are divided into different muscle groups according to the exercise, mainly including inspiratory training and expiratory training [29]. The training the muscle groups will be used in the inspiratory process. Inhalation is an active process that requires active contraction to expand the chest and reduce the pressure in the lungs. When the pressure in the lungs is lower than the atmospheric pressure, the air is sucked into the lungs. The diaphragm and intercostal muscles are responsible for normal inhalation. The diaphragm and the intercostal muscles are responsible for normal inspiration. When the diaphragm and the external intercostal muscles contract at the same time, the chest volume increases and the pressure decreases, so that air is drawn into the lungs [30]. In addition to the contraction of the diaphragm, inspiratory assist muscles are required during deep breathing and forced inhalation. The contraction of the steroid muscle raises the sternum, and the contraction of the scalenus muscle raises the ribs. As a result of these muscle contractions, the chest is lifted. Some auxiliary equipment can be used to train the inspiratory muscles to provide appropriate resistance. Inspiratory muscle training can increase the depth and breadth of breathing and improve the efficiency of breathing [31]. The mechanism of exhalation is the same as that of inhalation, both because of the difference in pressure, but because the pressure in the lungs is greater than the atmospheric pressure. When you exhale normally, the muscles do not contract. When the diaphragm and external intercostal muscles relax, the chest becomes smaller. When the pressures on the lungs increases, the air is expelled from the body. However, when some patients with or have had chronic lung disease or when the external airflow is limited, exhalation is not a completely relaxing process, instead of requiring the assistance of expiratory muscles [32]. When exhaling hard, the abdominal and internal intercostal muscles begin to contract, causing the ribs to move downwards. The contraction of the internal intercostal muscles also moves the ribs downwards, compressing the abdominal organs and forcing the diaphragm to rise, thus reducing the volume of the chest and increasing the pressure in the lungs, exhaling large amounts of carbon dioxide from the body [33]. Expiratory breath training can significantly improve the efficiency of gas exchange in the body [34]. In addition, the mechanism of airway concussion is often added to the auxiliary equipment of expiratory breathing training, so that patients with chronic lung disease can loosen sputum and promote sputum excretion while training breathing.

The common clinical breathing training methods are cough training and abdominal breathing. Its main purpose is to expel sputum from the main airway. Segmented cough or vocal cough instructs the patient to inhale deeply, then cough softly or gently, moving sputum from the distal bronchioles to the larger main trachea. Abdominal breathing is also called diaphragm breathing. During breathing, the diaphragm increased 1 cm and pulmonary ventilation increased 250 mL~300 mL [35]. The most important method of abdominal breathing exercise is to restrict the activity of the chest and force the abdominal movement to coordinate the vitality of the patient's diaphragm and abdominal muscle in the respiratory movement. The patient's chest breathing is changed into abdominal breathing. The method of abdominal breathing training is generally for the patient to take the supine position to relax the abdominal muscle, place the right hand on the sternal handle, place the patient's left hand on the navel, and remind the patient to inhale slowly with his nose to relax the patient's abdominal muscle as much as possible. As you exhale, push your left hand slightly upward. The patients are helped to tighten their abdomen, repeating for a period, and then rest for a period (1 : 2); circulatory breathing 10 min is 1 and 4 times per day [36]. Abdominal breathing exercise can improve patients' lung function and alleviate patients' dyspnea. The abdominal breathing exercise is more convenient, simple, and easy, without higher requirements for the physical quality of patients. Therefore, it can be widely accepted by patients and their families and in clinic. Some scholars have conducted a study on abdominal breathing training for patients with pulmonary dysfunction. After 20 days of intervention, it was found that the pulmonary function indexes FVC, FEV1, PaO2, and SpO2 of patients with type II respiratory failure increased significantly after abdominal breathing training, while PaCO2 decreased significantly [37]. Other scholars believe that abdominal breathing training can improve the enthusiasm and compliance of COPD patients to participate in treatment, shorten the length of stay of patients, and improve their quality of life [38]. In addition, based on routine treatment, Chinese scholars studied the effect of pike abdominal breathing on the respiratory function of patients undergoing laparotomy and compared the pulmonary function indexes with those before treatment. It was found that after two courses of treatment, the pulmonary function indexes FVC, FEV1/FVC, PaO2, SpO2, and PaCO2 were significantly improved [39]. The research results of other scholars showed that abdominal breathing training could not only improve patients' PaCO2 index and increase patients' pulmonary ventilation to prevent further deterioration of patients' condition but also relieve patients' anxiety, which has a good effect on patients [40].

The results of this study showed that the VAS score of the observation group after 3 d and 7 d of intervention was lower than that of the control group. Compared with the same group, the VAS score after 3 d and 7 d of intervention was lower than that before intervention, and that after 7 d of intervention was lower than that after 3 d of intervention, indicating that breathing training can be effective in improving postoperative pain in spinal nerve root entrapment syndrome, which is in line with relevant studies by Songhao and Linwen [41]. Respiratory training can increase pulmonary ventilation, improve pulmonary circulatory blood volume, increase blood oxygen content, promote pulmonary compliance, reduce sympathetic excitement and stress levels, and help patients relax and distract their attention, gradually relieving pain in the process of constantly adjusting breathing. The reason may be related to the decrease of patients' pain. The respiratory training diverts the patient's attention to pain in the process of adjusting breathing and improves the anxiety symptoms caused by a variety of postoperative pain. At the same time, through the deepening of respiratory exercise, effectively mobilize lung ventilation, the patients regulate autonomic nervous relaxation and reduce anxiety [42]. Our results have indicated that respiratory training after operation of spinal nerve root entrapment syndrome could promote the recovery of body function. Some studies have shown that abdominal breathing training can effectively reduce the sagittal angle of the spine and is conducive to the recovery of spinal function [43]. At the same time, abdominal breathing exercises can help patients with pulmonary ventilation, facilitating a speedy recovery and restoration of physical function. The method of respiratory training is simple and safe, so that the compliance of patients is improved. Our data has been related to the pain relief effect of respiratory training and the promotion of patients' initiative. At the same time, the medical staff should pay attention to pre- and postoperative care during the process of respiratory training. The patient is seen as an active individual, and the patient's initiative is given full play so that the patient is more actively involved in the rehabilitation process [44]. There are some limitations in this study. First, the sample size of this study is not large and it is a single-center study, so bias is inevitable. In future research, we will carry out multicenter, large-sample prospective studies, or more valuable conclusions can be drawn.

To sum up, respiratory training can effectively relieve postoperative pain, reduce anxiety, and improve spinal function in patients with spinal nerve root entrapment syndrome, which is beneficial to the prognosis of patients and is worthy of promotion.