Specific back pain – effective diagnosis and treatment from the radiologist’s point of view

Keywords

CT - interventional MR - diagnostic radiology - radiculopathy - back pain - infiltration therapy

Introduction

Specific back pain is a common condition. In radiology it has both diagnostic and therapeutic significance.

Specific back pain can be classified as radicular pain, which, depending on the compressed nerve root, leads to a corresponding pattern in the dermatomes, myotomes, and segment-indicating muscle(s) ([Table 1]). Nociceptive pain is pain caused by acute or chronic irritation in the facet joints, in the region of the end plates of the vertebral bodies, and in the region of the iliosacral joints. Nociceptive pain is usually characterized by localized pain but in some cases it can also radiate out in a pseudoradicular manner ([Table 2]). These types of pain are defined as morphological back pain.

Table 1 Commonly clinically affected nerve roots with corresponding dermatomes and associated movement segments.

Nerve root	Dermatome	Movement segment
C4	Shoulder	Shoulder elevation
C5	Lateral shoulder, deltoid muscle	Elbow flexion
C6	Radial upper arm and forearm, thumb	Wrist joint extension
C7	Fingers II to IV, extension side of the hand and forearm	Elbow extension
C8	Little finger, forearm ulnar side	Hand muscles
Th1	Medial side of the elbow region	Hand muscles
L1	Groin	Hip flexion
L2	Groin, proximal ventral thigh	Hip flexion
L3	Ventral thigh, middle third to distal third	Knee extension, adduction
L4	Lateral thigh, patella, medial lower leg	Knee extension, hip flexion
L5	Extension side of the lower leg, extension side of the foot, big toe	Lifting of the big toe, lifting of the foot
S1	Dorsal thigh, dorsal lower leg, lateral foot, heel	Lowering the foot, thigh extension, thigh external rotation

Table 2 Facet joint degeneration: Location and typical symptoms.

Location	Symptoms
Cervical	Cervical pain, particularly during rotation and/or reclination, headache partially spreading upward.
Thoracic	Thoracic pain during rotation and/or flexion, partially radiating to the ribs, limited mobility.
Lumbar	Low-lying pain primarily after a longer period of strain, morning start-up pain. Radiating into the groin, hip, and lateral thigh.

In specific back pain, it must be taken into consideration that overlying nociplastic pain can also be present, i.e., the back pain is centrally modulated [1] [2]. Depending on the pattern of degenerative or traumatic changes in the spinal column, radicular and nociceptive pain can both be present.

Back pain is an important medical issue as evidenced by multiple key figures. 60% of patients with specific back pain have continuous or recurrent back pain one year after diagnosis. 15–40% of patients with confirmed symptomatic radiculopathy develop a chronic pain syndrome or suffer from regular recurrence [3]. In addition, the prevalence of specific back pain increases with age [4].

Specific back pain must be clearly differentiated from nonspecific back pain. In the case of nonspecific back pain, there is no morphological basis for the pain. In the case of nonspecific back pain, primary imaging is not indicated [5] [6].

The most common degenerative causes of specific back pain in the region of the neck, chest, and the lumbar spine in adults are discussed in the following narrative review. In addition, the diagnostic possibilities, therapeutic options, and their limitations are examined.

Method

A detailed literature search regarding specific back pain, radiological interventions, and imaging was performed. A further focus was on the corresponding German guidelines regarding back pain. The European and American guidelines were also taken into consideration. Complementary areas like surgical/orthopedic therapy, behavioral therapy, and physiotherapy were also included in the expanded search ([Fig. 1]). The plausibility of the results and feasibility of recommendations for practical application in patients under consideration of the available resources in the German health care system were taken into consideration when selecting articles so that the review can provide practice-based and patient-centered information.

Fig. 1 Compilation and selection of literature.

Results

Causes of specific back pain

Intervertebral disc: The intervertebral disc acts as a buffer between the vertebral bodies. Dorsal bulging or herniation results in narrowing of the spinal canal and possibly, depending on the morphology of the damage, also in combined or isolated narrowing of one or both neural foramina or the recess.

Facet joints: As joints between the vertebral bodies, facet joints can exhibit arthritic changes combined over time with hypertrophy and depending on the type of load also with inflammation. Quickly progressing and pronounced facet joint arthritis can also occur when spondylolisthesis is present.

This can result in neural foraminal narrowing with intraforaminal nerve root involvement or spinal narrowing with intraspinal or recess nerve root involvement. These can also occur in isolation or in combination independently of local inflammatory pain symptoms.

Spinal canal: Narrowing of the spinal canal due to disc herniation, spondyloarthritis, lipomatosis, ligamentous hypertrophy, or a combination thereof. This results in nerve involvement in the spine or in the recess.

Vertebral bodies: Degeneration and non-traumatic microfractures of the end plates result in local pain symptoms at the level of the changes.

CNS: When examining specific back pain as well as nonspecific back pain, the central nervous system must also be taken into consideration. Numerous studies have shown that significant morphological changes that do not cause any symptoms are present in many people. In others, slight morphological changes in the spinal column result in significant immobilizing pain. Therefore, pain modulation and pain perception as a result of the nervous system must be taken into consideration [4] [7] [8].

Patient information

Imaging must always be performed based on the symptoms. One study indicates that patients with knowledge of the MRI findings feel worse than patients without knowledge of the findings [9]. Another study showed that particularly patients in whom MRI examination did not show any pathology in the region of the back, experience more severe and longer-lasting symptoms than patients in whom nerve involvement could be shown as the cause on MRI [10].

It should be noted in this connection that there are major differences in the communication of the findings in radiology. Some colleagues avoid the direct communication of findings or explain findings to patients in language that is incomprehensible to medical laymen. Depending on which approach is selected, patients can have a very individualized reaction with respect to the further course and prognosis of their disease [11] [12] [13].

Therefore, it is important, particularly in the case of a condition as common as back pain, to provide the proper support for patients through the phases of their disease. Patients must understand that targeted treatment can only be implemented when the imaging findings coincide with the symptoms, i.e., the pain is specific back pain and not back pain with concomitant, currently asymptomatic pathologies that were only incidentally detected by imaging. In this chain of causation, radiology is the first to deliver the diagnosis and can have a positive effect on the healing process [12].

The guidelines “Lumbar Radiculopathy” as well as “Specific Back Pain” clearly define specific back pain and show that clinical and physical examination provides important information regarding the etiology of the back pain. Based on the patient’s symptoms and an examination, specific back pain can thus be differentiated relatively reliably from nonspecific back pain. In daily practice it may not be possible to perform a sufficiently thorough examination so that imaging is performed too early or is not specific enough.

According to the guidelines above, MRI, possibly supplemented by X-ray on two planes with the patient in a standing position, is to be considered the cross-sectional imaging method of choice.

A CT examination is recommended if MRI is contraindicated.

The guidelines state that a patient’s symptoms can in some cases be aggravated by imaging that is not indicated and incorrect communication of findings [5] [6]. The only literature on this topic is from the year 2005 [9]. Newer studies show that in younger patients under the age of 50 there is an association between back pain and pathologies identified on MRI without being able to show clear causality [7]. In patient groups with severe back pain, a correlation between MRI findings and patient symptoms could also be found [14].

On the other hand, the human body experiences normal wear and tear, which also increases in the spinal column with age. When only considering asymptomatic patients, both intervertebral disc herniation and spondyloarthritis are seen to varying degrees. However, many studies on asymptomatic patients are not focused on the course of the disease but rather on a specific point in time in the medical history. However, since both degeneration of the vertebral joints as well as herniation of the vertebral discs can persist as a morphological imaging finding beyond the symptoms if surgical intervention is not implemented, the method used in many studies should be examined with a critical eye at least with regard to morphological imaging findings in asymptomatic patients. In addition, many studies cited in current reviews are relatively old with an average publication date of 9.8 years ago [7] [15] [16].

In contrast, other studies show that certain degenerative changes causing deformation in the spinal column can be significantly associated with symptoms [4] [17].

There are also some studies that were able to show that there is a correlation between MRI findings and pain symptoms in older people. This is even more pronounced the greater the indication for MRI. This confirms the principle of the guidelines “Specific Back Pain” and “Lumbar Radiculopathy”: clinical examination first, then initiate targeted imaging [4] [5] [6] [18].

In our opinion, radiology must therefore play a key role. Of course, radiology should not replace clinical and referring physicians. However, in the case of a referral for MRI of the complete spinal column with the suspected diagnosis “acute dorsalgia”, a brief conversation with the patient is needed. This can or must be combined with a brief targeted clinical examination. A probable suspected diagnosis must be made, and the examination must be performed in a targeted manner. This makes it possible for the patient to receive a fast and correct diagnosis and quick treatment while also preserving resources.

The guidelines provide very good starting points for the targeted determination of the correct examination [5] [6] ([Table 1], [Table 2]).

Radiological examination

The etiology of back pain must be taken into consideration particularly with regard to a fast and targeted diagnosis.

In the case of nonspecific back pain, imaging should not be performed in the first 6 weeks after the initial onset of symptoms. Exceptions include red flags, i.e., circumstances that indicate an acute risk, like paralysis, limited mobility, clear radicular symptoms, etc. [5] [6]. If it is taken into consideration that there are significant wait times to see a physician or specialist in Germany and many other countries, this requirement must be understood in terms of the guidelines “Non-specific Back Pain” [19]. Imaging should not be performed 6 weeks after the initial consultation but rather 6 weeks after the onset of symptoms in the case of persistent symptoms.

A current study on back pain was able to show that patients 65 years and older went to the doctor on average 10 weeks after symptom onset and patients under the age of 65 contacted the treating physician on average 17 weeks after symptom onset [4].

There is a lack of consensus with respect to the use of conventional X-ray in the workup of back pain. The indication and appropriate use, particularly with regard to radiation protection, are increasingly the topic of critical discussion [20] [21] [22].

In the case of suspicion of a symptomatic pathology caused by malposition or malformation, i.e., scoliosis or spondylolisthesis, based on symptoms and physical examination, conventional X-ray of the spinal column on two planes with the patient in a standing position is indicated [23] [24] [25].

Conventional X-ray of the spinal column on two planes in the case of suspicion of specific, non-traumatic back pain is not recommended due to the limited diagnostic significance. However, X-ray is still permitted according to the guidelines [5] [6] [22].

The diagnostic significance of conventional X-ray is limited. Particularly when spinal or neural foraminal nerve root involvement is suspected, conventional X-ray can provide maximum information to indicate additional cross-sectional imaging. However, an unremarkable X-ray of the spinal column does not rule out spinal or neural forminal nerve root involvement.

If the clinical symptoms result in suspicion of a radicular or pseudoradicular cause, MRI examination of the corresponding region is indicated. Narrowing of the spinal column as well as the neural foramina can be specifically evaluated. In addition, MRI provides not only information about concomitant spondyloarthritis but also shows possible inflammatory spondyloarthritis that can be treated in the case of corresponding symptoms. Contrast agent is not needed for this examination. There are numerous studies showing that bone marrow edema and/or concomitant fluid collection in the joint on fat-suppressed T2-weighted images are a clear indication of activated spondyloarthritis [26] [27].

The opinion in the guidelines that facet joint injection can be performed to confirm the diagnosis is not shared by all experts [28]. In addition, how the medication mixture to be applied to the facet joint is actually distributed should be examined. Due to the anatomically very narrow joint space, some of the medication is always located outside the facet joint and has an effect there. As a result of the immediate proximity to the neural foramen, the exiting nerve is also affected and thus the patho-anatomy may be incorrectly or not fully evaluated, e.g., when neural foraminal narrowing is present in addition to activated spondyloarthitis [4].

MRI examination makes it possible to better understand the underlying disease in such cases by means of precise analysis of the involved structures. Thus, edema in the region of the joints, the nerve root, and the end plates of the vertebral bodies indicates an acute pathology. Direct edema detection is performed using a fat-suppressed T2 sequence. Contrast enhancement in the facet joint as well as perineural contrast enhancement indicate an underlying acute pathology.

Contrast agent is not necessary in most cases since the detectable swelling of the nerve and the edema are sufficient indications of the underlying pathology [29] [30] [31] [32] [33].

Thus, MRI examination appears to be the most diagnostically significant examination available. Moreover, it is radiation-free. It allows both the biomorphological classification of radicular or pseudoradicular symptoms as well as the diagnosis of clearly degenerative changes in the end plates of the vertebral bodies as well as in the facet joints. This method also provides information about whether the degeneration includes acute inflammatory changes at the time of the examination. A diagnosis can thus be confirmed or ruled out, thereby saving the patient from undergoing an unnecessary treatment attempt.

A current MRI examination is recommended both by the neurological guidelines “Lumbar Radiculopathy” and the orthopedic guidelines “Guidelines on Conservative, Surgical, and Rehabilitative Care of Intervertebral Disc Injuries with Radicular Symptoms” with the clear requirement that the patient symptoms and the finding must coincide. In addition, it must be noted that an overinterpretation of the MRI findings must be avoided to prevent patient uncertainty [6] [34]. In our opinion, this should be given special emphasis because based on the morphological criteria above MRI examination makes it possible to determine whether there is nerve root involvement. For this reason, at least one fat-suppressed T2 sequence should be integrated in the MRI protocol ([Table 3]).

Table 3 Sample MRI protocol.

	Cervical spine	Thoracic spine	Lumbar spine
Coil	Head-neck coil, spine coil	Spine coil	Spine coil
Examination volume	Craniocervical junction to cover plate of T1	Base plate of C7 to cover plate of L1	T12 to the sacral bone
Slice thickness 2D	≤ 3mm	≤ 3mm	≤ 3mm
Slice thickness 3D	≤ 1.5mm	≤ 1.5mm	≤ 1.5mm
Sequences	T1, T2, T2 fat saturated; sagittal, transverse, coronal if necessary	T1, T2, T2 fat saturated; sagittal, transverse, coronal if necessary	T1, T2, T2 fat saturated; sagittal, transverse, coronal if necessary

Radiological treatment options

Radiologists also play a decisive role in multidisciplinary pain therapy. If specific back pain is confirmed and a clear origin can be diagnosed clinically and morphologically, minimally invasive treatment can be performed under imaging guidance. It is important to treat in a highly precise manner so that multiple segments are not treated unnecessarily. Therefore, treatment should be as minimal as possible and performed at as few sites as possible. The relative precision is as important as a precisely defined target. Key word: Imaging and symptoms.

MRI, CT-guided epidural/neural foraminal injection, facet joint injection/facet joint denervation or combinations of these methods can be used as possible radiological treatment methods. A further treatment field for interventional radiology in pain therapy is the treatment of space-occupying synovial cysts.

The therapeutic approach should be selected based on the type of nerve compression, e.g., by a disc and/or bone degeneration and/or synovial cyst.

The goal is to limit local inflammation by applying the medication in a targeted manner under imaging guidance to the site at which the pain originates and thus to improve symptoms or ideally to eliminate symptoms.

If the clinical symptoms are caused by nerve root involvement due to intervertebral disc herniation or neural foraminal compression by bone, periradicular therapy should be considered as a promising method.

Transforaminal anterolateral access, transforaminal lateral access, transforaminal posterolateral access, interlaminar dorsal access are used for epidural and peridural injection therapy [35] [36] [37].

In transforaminal interventions, a trocar is placed in the immediate vicinity of the neural foramen under CT or MRI guidance ([Fig. 2]). The position of the trocar is monitored until it reaches an optimal location in the immediate vicinity of the site of pain origination. Once the trocar is correctly positioned, the medication is administered. The medication is usually distributed in the epidural space along the nerve root and can be followed in the epidural space into the spine. Some of the medication can also be detected around the nerve and in the adjacent fat and soft tissue [38].

Fig. 2 Various approaches for minimally invasive radiological pain therapy.

As an alternative, an epidural translaminar approach can be selected with access between the dorsal segments of the vertebral arches being selected and the medication being injected after verification of the correct epidural location [39].

The complication rates of the various approaches are comparably low [40].

If activated facet joint arthritis is the cause of symptoms, the trocar is positioned directly in the facet joint or directly next to it and the medication is injected there. In this case only minimal amounts of the medication are seen directly in the joint gap, while a significant amount is seen around the joint.

In the case of facet joint injection, some authors also differentiate nerve block of the medial branch of the dorsal branch of the facet joint. This nerve block is used to treat the branches innervating the joint capsule and the facet joint [41] [42]. A combination of transforaminal access and accompanying facet joint therapy is also possible in the case of a corresponding clinical and morphological etiology of the symptoms.

Facet joint denervation as a radiological method uses physical ablation of the medial branch of the dorsal branch or the joint capsule of the facet joint. Radiofrequency ablation with various technical modifications like cooled, pulsed, chemical, or thermal radiofrequency ablation can be performed under imaging guidance [43] [44] [45].

Synovial cysts are observed as an accompanying symptom in facet joint degeneration, and some may increase in size over time. These fluid-filled cavities with a capsule are in a periarticular location and can compress the neural foramen, spinal canal, or both spaces depending on the location. The resulting nerve involvement can be resolved by mechanical rupturing of the synovial cyst. During this intervention, the cysts are probed and ruptured by means of an injection. Different work groups use different substances as well as quantities. In many cases, cortisone is used. In some cases, the cyst is ruptured with a physiological saline solution and then cortisone is administered. The interventions have been performed under fluoroscopy guidance as well as cross-sectional imaging guidance [46] [47] [48] [49]

The distribution volume of the administered medication that is anatomically available is very small. In one study the anterolateral epidural space in segment L5/S1 had a mean volume of 1.1 ml in the anatomical cases and 0.9 ml in the surgical cases [50]. According to experimental calculations, the intraarticular space in the facet joint is a few µl and is not filled with fluid detectable on imaging under physiological conditions [51]. The intraarticular space of the facet joint can only be filled with fluid in the case of degeneration or an acute inflammatory or traumatic change. Even in these cases, the distribution volume is very small.

Dosage

In many studies and also in the German guidelines on specific back pain, triamcinolone is described as the medication of choice. 10 mg per injection is recommended as the optimal triamcinolone dose [6] [19] [34] [52] [53]. The literature also reports single doses of up to 80 mg [52]. The basis for this dose recommendation in the range of 10 mg which is also used in the guidelines is the fact that a higher dose was not able to show any statistically significant benefit regarding the symptom elimination and patient satisfaction and at the same time a low dose is desirable to avoid serious side effects of triamcinolone like insomnia, facial flushing, nausea, fever, and in rare cases dysfunction of the hypothalamic-pituitary axis. Hypertension, edema, and menstrual irregularities have also been described as side effects. It must be taken into consideration that in high-risk patients like diabetics and patients with osteoporosis even low doses can cause serious side effects [53]. Since there is a dose-side effect relationship, the dose should be kept as low as possible [6] [53] [54].

Treatment

There are significant differences regarding dose, treatment time intervals, and the total number of treatments performed. Individual studies report performing only one treatment [55]. Many conduct series of treatments with the number of injections varying between 1 and 8.

There is also no consensus in the literature regarding the absolute number of epidural injections that can be performed per year. In addition, different medications are used for the injection. The spectrum ranges from isotonic saline solution and homeopathic drugs to local anesthesia and glucocorticoids. Cytokine antagonists have also been used under experimental conditions. A combination of glucocorticoid and local anesthesia is often administered. The greatest number of results have been reported for this combination [52] [53] [56] [57].

To avoid possible side effects and complications, it must be considered after every treatment whether a further treatment should be implemented. Particularly in the event that no improvement is seen after the first treatment (the patient should have already been informed in the informed consent discussion that it may take a couple of days to see improvement), there is currently no consensus as to whether additional injections should be administered after failure of the initial treatment [58].

Two treatment attempts at the same location are justified when there is a clear correlation between the patient’s symptoms and the morphological correlate on imaging. In the case of multilocular symptoms that coincide with imaging results, a test injection should be performed prior to the administration of drugs containing corticosteroids to precisely locate the relevant pathology, especially since studies show that there is high variability in nerve blocks regarding the size of the response area and the extent and overall response. Thus, the relevant segment can be preselected in certain cases without the unnecessary administration of a glucocorticoid. Such an approach is particularly important in diabetics, who often experience significant metabolic crises as a result of the epidural administration of glucocorticoids [58] [59] [60].

In the case of facet joint injection, there is an even clearer constellation of findings: The symptoms and the inflamed segment must definitively coincide. In cases of doubt, the segment can be checked by pain point marking in combination with fat-suppressed T2-weighted imaging, e.g., STIR, performed immediately before the intervention. Segmental pain should improve greatly after injection. In this case, the combination of glucocorticoids and local anesthesia is recommended. If this does not occur, the position of the trocar and the distribution of the medication mixture must be examined. If both of these factors are correct, the indication must be reviewed and the segment or the type of treatment must be adjusted as needed [61] ([Fig. 3] and [Fig. 4]).

Fig. 3 Flowchart: Radiological workup and treatment in the case of back pain.

Fig. 4 Flowchart: Radiological pain intervention process.

Outcome

The initial improvement in symptoms after imaging-guided interventional treatment of specific back pain is generally considered to be good and reproducible. Only a few long-term studies have been performed after imaging-guided interventional pain treatment [38] [58] [62] [63]. One study shows that 15% of 90 observed patients were completely symptom-free after five to seven years, while approximately 50% reported good symptom improvement but also stated that they had to be treated at least once more in the interim. 25% of patients underwent an operation in the interim. In total, a reduction in the pain score from 6.7 prior to treatment to 3.7 in the follow-up survey after 5 to 7 years was seen in the entire observed group. The study did not include a control group. The follow-up interviews were performed via telephone [64].

Another study reported an improvement in the pain score for PRT patients from 7.3 before the intervention to 4.0 over the course of 54 weeks. Patients who underwent facet joint injection experienced improvement from 6.9 to 4.5 after the intervention [65].

Another study reported an improvement in pain symptoms in 75% of treated patients who specified a pain reduction of 50% or more at the 3-month follow-up. In this patient group, 25% did not see any positive effect after 3 months [55].

Another study reported moderate to good pain reduction in 95% of treated patients and stated that the treatment success lasted 9 months on average [66].

Facet joint therapy also shows initial good improvement of symptoms as a result of both energy ablation therapy and injection of glucocorticoids or other medications. Neuropathic pain has been observed as a complication of electro-ablative and chemical-ablative procedures. During facet join therapy, injection with glucocorticoids typically initially shows a better response and better pain reduction than ablative procedures. Ablative procedures provide longer-lasting pain reduction over time. However, depending on the study, the effect begins to abate after 6 to 24 months [43] [44] [45] [67]. Therefore, even ablative methods have only a limited duration of action [68] [69]. In general, a positive response can be expected within several days of interventional pain therapy [38] [43] [44] [45] [67].

The literature does not show any significant differences in the effectiveness of minimally invasive radiological pain treatment depending on the treatment location. Most studies focus on the cervical spine and lumbar spine, while studies on the thoracic spine are less common [70].

The results after cyst rupture under cross-sectional imaging guidance have success rates of up to 82% with satisfactory to good symptom improvement for patients over an observation period of up to 2 years. Interestingly, if cyst rupture was not successful during the first treatment attempt, future attempts are typically also unsuccessful [46] [47] [48] [49].

In the case of an insufficient response of pain symptoms to treatment, repeated injections can be used for treatment [65] [70] [71].

In radiological pain treatment, the often multifactorial origin of back pain should be taken into consideration and other therapeutic measures should be included in the treatment – ideally in a multidisciplinary/multimodal concept.

Radiological pain intervention often makes it possible for patients to participate in targeted and lasting pain therapy since the quick reduction in pain achieved by the intervention allows patients to regain their mobility. This regained mobility can and should be used for targeted exercises possibly under supervision and also allows patients to participate in life again. Being able to actively participate in life avoids depression, which is a common condition that accompanies back pain, is correlated with a negative outcome, and often becomes chronic [72] [73] [74].

It is even more important in the case of a lack of treatment response to reevaluate the indication and symptoms and to stop treatment early in the case of treatment failure to spare the patient possible treatment-induced side effects and to implement an alternative treatment regime [53] [60] [75].

Medications

The injected medications used In many studies are glucocorticoids as long-lasting anti-inflammatory drugs. As a rule, these are administered in combination with a suitable local anesthesia. However, there are also studies that only administer local anesthesia and achieve good symptom improvement at least in the initial phase. The improvement lasted longer than could be ascribed to the pharmacokinetics [76]. Various pharmacological subgroups of glucocorticoids and local anesthesia are also used and are also compared in some studies [77].. A physiological saline solution has also been used in various studies. Interestingly, one study discusses whether a physiological saline solution can be considered a placebo or whether there is an active component [78].

Gender and age as factors

Current studies show that pain perception is gender-specific. This is interestingly dependent on both the gender identity as well as the gender assigned at birth. The underlying mechanisms are not fully understood. A multifactorial origin can be assumed since hormonal factors, physiological factors, and factors related to the central nervous system have been described with regard to sensation of pain and pain perception.

Pain perception as well as the handling of pain differs between men and women with regard to both the genetic gender and the gender identity. In addition, cultural and socioeconomic factors affect the experience of pain, expression of pain, and pain perception [79] [80] [81]. There is a tendency toward increased occurrence of symptoms with age. However, it must be taken into consideration that the greater incidence of back pain in older patients does not correlate with the degeneration seen with age. The backs of old people compared to young people have more pathologies that can cause pain, but these age-related physiological changes do not automatically result in pain [4] [82].

Non-radiological treatment options

The following focuses on the most common treatment options for specific back pain. Due to the broad spectrum, not all aspects of the possible treatment options can be discussed in this primarily radiological review.

Surgical treatment

In recent years, there has been a focus on surgical interventions for specific back pain, particularly in English-speaking countries. Intervertebral disc replacement as well as expansion of the spinal canal with or without spondylosis typically result in quick elimination of symptoms but do not show a significant advantage compared to conservative treatment over the course of 1 to 2 years [83] [84].

In the case of severe spinal canal stenosis, the literature shows an advantage of surgical treatment compared to conservative methods [85]. In 2016, the NICE guidelines recommended surgical intervention for patients with confirmed spinal stenosis in the case of concordance between symptoms and radiological findings provided that conservative treatment measures have been exhausted without achieving any lasting improvement [86].

Over time, recurrence of pain symptoms in the form of back pain or radicular symptoms or in some cases a combination of both is seen in 10–40% of surgical patients. The following reasons have been described: Adhesions, nerve injury caused by surgery, arachnoiditis, spinal instability [87] [88]

Behavioral therapy, patient education, and physical therapy

It is difficult to treat specific back pain since there is often a psychological component in addition to the morphological cause detected on imaging. A negative attitude, pain-based fear, and various resulting avoidance strategies play an important role [89]. According to the recommendations, bed rest and lack of activity should be avoided. Activities like yoga, tai chi, and targeted exercises have positive side effect-free results [90] [91] [92].

Studies on the use of cognitive behavioral therapy were able to show that restructuring of the patient’s negative perception to a more realistic view of the pain situation and changing of the patient’s perspective can have a positive effect on improvement. Intentional use of mindfulness as a therapeutic instrument can improve pain symptoms [93]. Targeted use of physician-patient interactions can have a positive effect on the course of specific back pain. Multiple studies have shown that a patient-centered, empathetic approach significantly improves patient symptoms [12] [94].

There are indications that targeted patient education in the form of individual therapy or group therapy results in faster pain reduction and better quality of life [95] [96]. Since all of these types of treatment are typically completely side effect-free, they should always be recommended as a supplementary and supportive form of treatment when possible.

Side effects

The intraarticular, epidural, and peridural administration of glucocorticoid derivatives is a common treatment for back pain. There is a risk of disrupting blood glucose metabolism and also disrupting the hypothalamic–pituitary–adrenal axis.

A prospective study including 6 diabetics and 12 non-diabetics who received an epidural injection of 8 mg of dexamethasone with subsequent monitoring of blood glucose metabolism and the adrenocorticotropic hormone axis showed that on day one after the intervention the fasting glucose level in both groups was elevated and the adrenocorticotropic hormone and serum cortisol levels were significantly reduced. The post-prandial glucose values and all values did not deviate significantly over time. This study shows a measurable but clinically irrelevant side effect profile both for diabetics and for non-diabetics [97].

An older study using 250 mg of a prednisone equivalent administered over 3 days – epidural injection as well as intraarticular injection in the shoulder were observed in this study – showed comparable results in relation to day 1 after the intervention. In the further course, the diabetics showed an increase in the postprandial blood glucose level on day 1 and day 7 [98]. Another study compared 14 type II diabetics with 15 non-diabetics with respect to the one-time administration of 40 mg of triamcinolone either into the shoulder joint or as a lumbar epidural injection. An elevated fasting glucose value one day after treatment was detected in all treated patients and suppressed cortisone values were seen one day and seven days after treatment.

Diabetics who received epidural administration of 40 mg of triamcinolone did not show complete normalization of their serum cortisol values after 21 days [99].

On the whole, the literature describes the administration of glucocorticoids as unproblematic even in diabetics. There is a recommendation to use as little glucocorticoid derivatives as possible and to keep the intervals as long as possible in the case of repeat treatment. In addition, patients should intensively monitor their blood glucose levels and administer a corrective dose of insulin if blood glucose levels are elevated in the case of a primary insulin dependence prior to the treatment [53] [97] [98] [99].

Limitations

As shown above, the presentation of specific back pain to be treated radiologically is diverse and multifactorial both with regard to etiology and in relation to treatment options and possible combinations of treatment options.

The fact that central perception and pain experience play an important role complicates the long-term evaluation of imaging-guided interventional pain treatment methods as well as of all other surgical and non-surgical methods. Central pain processing can be modified by medications, lifestyle, and psychological training so that a number of factors that cannot be comprehensively recorded and evaluated affect long-term observation. Therefore, in our opinion, the treating radiologist should either be part of a pain management team so that as many factors as possible can be treated in a targeted manner by various specialist groups or the radiologist informs the patient prior to treatment of the imaging-guided interventional pain treatment options and shows the patient useful further options to support treatment, e.g. exercise, positive social activities, resumption of hobbies, return to work, etc.

Summary

In the case of specific back pain, radiology can use a targeted diagnostic workup in combination with a targeted patient history and physical examination to precisely determine whether a morphological correlate for the patient’s symptoms is present. If this is the case, radiology can provide fast improvement of symptoms with minimal side effects by means of targeted interventional pain therapy. The indication and treatment must be reviewed closely from the beginning and modified if necessary. If treatment is unsuccessful, it must be terminated early. Treatment should also be embedded in an expanded multimodal concept to prevent a recurrence of pain and the possible development of comorbidities.

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