**1. Introduction**

Spinal orthoses are used for spinal complaints in a very undifferentiated manner. This concerns the medical clarification as well as the selection of the aids. The international literature has referred to the clarification of a treatment algorithm.

The goal of orthotic care for spinal disorders is to reduce discomfort while activating the patient. This is achieved by segmental spinal stabilization and/or position correction. However, a targeted reduction of discomfort is only possible if the cause of the discomfort is known. This results in the requirement for a structured clinical examination, followed by imaging procedures.

A structured treatment concept is required for orthotic care, comparable to surgical planning. Undifferentiated indications bring orthotic treatment into disrepute, and the opinion of physicians regarding this form of treatment may be classified as negative. Nevertheless, the prescribing behavior is surprisingly generous in, for example, Austria. It is not the intention of this article to present this discrepancy. Rather, it aims to provide a guideline for structured care. The structure of this article is based on orthotics of the thoraco-lumbo-sacral spine.

The current literature is focused on lumbar complaints and thus on quickly available adaptable orthoses (adaptable device = industrial products).

This article attempts to reconcile the medical indications with the biomechanical criteria for orthotic fitting, and to address the following questions: does the current literature support the indication of spinal orthosis treatment in low back pain, and what treatment concept can be derived from the result? We hypothesized that if the cause of low back pain is not clarified and differentiated, no targeted effect may be expected from orthotic fitting.

## **2. Methods**

The present article follows the current PRISMA criteria from 2020. This report comprises a literature review for which the current literature was first searched in PubMed on 30 October 2021 for the MESH terms "low back pain and spine orthoses", then updated on 30 December 2021. Excluded were all articles related to Kinesio Taping, scoliosis, physical exercise programs and articles unrelated to treatment effect. Papers related only to a side effect were not included in the literature list. A general definition of low back pain and spine orthoses is given. Thus, the literature list refers only to "low back pain and spine orthoses" and resulted in 30 matches [1–30]. If the cause of the complaints was mentioned in an article, said article was assigned to group (A) with specific diagnosis.

Papers that did not provide a definite indication of the cause of pain were assigned to group (B), "specific diagnosis is not given". Orthoses were differentiated in the same way. Articles with clear biomechanical information about the orthosis were called "diagnosis based orthosis" (group C). All other articles with only general biomechanical information were assigned to the group "unspecific orthotic treatment" (group D).

For the treatment concept, the next step was to create a structured differentiation of the orthoses. The differentiation was made in accordance with colloquial terms because a generally accepted definition or classification does not exist. In a further step, a standardization of the orthotic indication was created in accordance with the different causes of pain. This resulted in a clarification concept for the cause of pain and subsequently a functional, biomechanical treatment goal for the orthosis selection. This concept was summarized in tabular form.

The risk of bias lies in the choice of the MESH terms. The synthesis of the results yielded a clinical treatment concept based on findings from the current literature.

#### **3. Results**

In the first search, 43,153 papers ("low back pain") were found; when adding "brace", 318 remained, 4949 for "spine support" and 3623 for "lumbar support". For "orthoses", 391 papers remained. The abstracts were searched for the exclusion criteria as described

above. Thereafter, 54 papers remained for full-text screening, which resulted in full-text analysis of the 30 papers presented here with clinical relevance ([1–30], Figure 1).

**Figure 1.** Flow diagram.

Literature citations with 1749 patients and 2160 citations were processed. Ultimately, 21 prospective clinical or biomechanical studies and 9 review articles were included.

The following definitions of low back pain and spine orthoses were used:

Low back pain was defined as pain of musculoskeletal origin extending from the lowest rib to the gluteal fold that may at times extend as somatic referred pain into the thigh (above the knee). The definition of the North American Spine Society (978-1-929988- 65-5) of an orthosis is as follows: A brace, splint, or other artificial external device serving to support the limbs or spine or to prevent or assist relative movement [13].

Many different terms are used for back orthoses (spinal orthoses, spine support, back supports, braces, bandage, girdle spine support, bodice, corsage, corset etc.).

This concerns the choice of words used, the indication for the orthotic fitting as well as its mode of action and design. A generally valid definition is lacking. There is only a general classification in ISO 8549-3:2020(en) (see Tables 1–3).

#### *3.1. Overview of the Current Literature*

The cause of the complaint must be diagnostically narrowed down.

The orthosis must be clearly defined in terms and function (Table 1).

Only when a differentiated cause of the complaint according to "specific diagnosis" was determined (group A) and the appropriately adapted "diagnosis based orthosis" was used (group C), were positive effects found in prospective studies ([2,5,9,22,28,30], Table 1), one retrospective study ([28], Table 1) and one review article ([10], Table 2).

No positive effect was prescribed in postoperative prospective studies ([20,23,25], Table 1) and one review article ([29], Table 2).

When no specific diagnosis is given (group B) and nonspecific orthotic treatment is administered (group D), no consistent result can be expected. The listed prospective studies ([1,6,8,11,14,17–19], Table 1) and review articles ([12,13,15,16,24,26,27], Table 2) demonstrated no positive effect. An effect was described in three biomechanical studies ([3,4,7], Table 1) and one postoperative study [21].

All meta-analyses and literature research reviewed did not provide medical or technical differentiation [1,6,8,11–19,24,26,27]. Thus, general orthotic designations such as "lumbar support" are used in the following. A general conclusion could not be found.

No review articles were identified where specific diagnosis was not given and orthosis with unspecific treatment was combined.

**Table 1.** Therapy effect in the literature for prospective studies and one retrospective study, depending on cause of complaint and orthosis.


**Table 2.** Therapy effect in the literature for review articles depending on cause of complaint and orthosis.


*3.2. Summary of the Literature and Whether It Supports the Indication of Spinal Orthosis Treatment in Low Back Pain*

In the examined scientific literature we found a wide range of terms for orthoses. The terms did not give a clear indication of the orthosis used (orthosis, lumbar support, lumbar belt, brace, bandage, bodice, corset, pelvic orthosis, LSO (lumbosacral orthosis), low-profile exosuit, TLSO (thoraco-lumbar orthosis), hip orthosis, lumbar corset, bracing, back belt, rigid brace). Conversely, in biomechanical studies, clear descriptions could be found ([1–5,7,11], Table 1).

The medical descriptions of the complaint did not always indicate the cause of pain. Wordings were non-specific with regard to low back pain, back pain, etc. [6,8,14,17–19,22,27,28]. Within meta-analyses, review articles and an online survey, the causes of the pain were not differentiated [10,12,15,16,24,26,29]. In all cases of postoperative treatment, clear information about the clinical situation was given [20,21,23,25,29]. Only in one clinical study was clear information (MRI-Modic 1) given [28].

#### *3.3. Differentiation of Spine Orthoses*

In the following we make an effort to systematize the different terms used to describe orthoses and to link them to complaints and diagnostics.

Bandage (Soft orthosis with or without pads):

Protective, supporting bandage, soft/elastic (i.e., encompassing body parts with/ without pads).

The indications for fitting are acute or chronic complaints diagnosed by clinical examination. The mode of action is through a circular socket and force application via a pad.

The diagnosis is considered to be mild, chronic or recurrent pain in the lumbar region (back support brace with dynamic pad, Figure 2).

**Figure 2.** Bandage "Soft orthosis with or without pads".

Furthermore, spinal pain with moderate instability and lumbalgia are specified (lordosis/correction/bandage).

Bodice (girdle spine support, soft orthoses with struts, spine support, corsage):

Locally differentiated diagnoses are defined as indications for bodices. X-ray imaging is recommended for indication.

The mode of action is via stiffening elements that overlap and stabilize body regions. Delordosing of the lumbar spine is the major goal.

The diagnosis of recurrent pain in the lumbar spine or at the thoraco-lumbar transition is the primary focus (e.g., lumbalgia, dorsalgia), postnucleotomy syndrome and for postoperative immobilization, but also instability, etc. (spine support with struts, Figure 3).

A distinction must be made between height differentiations with anatomical assignment as stretching only the lumbar spine (LSO) or including the thoracic spine (TLSO), etc.

Spine support with abdominal sling for delordosis and relief of the segments of the lumbar spine (in case of highly protruding abdomen, pregnancy, etc.).

Corset (soft orthoses with a rigid part to encompass the pelvis or a rigid orthoses):

Diagnosis of ailments that can be treated by correction and/or stabilization over the pelvic area form the indication for corsets.

Their mode of action is the correction in the sagittal and frontal planes and the limitation of rotation. This results in a degree of limitation that recommends slice imaging (CT or MRI) in most cases.

Segmental instabilities, spondylitis or spondylodiscitis, tumors and metastases, fractures without significant change in shape etc. are the most common indications.

A special form of indication is a bridging corset with the possibility of gradual release of movement (e.g., as postoperative care; Figure 4). The corset becomes a bodice by removing the pelvic frame and a bandage by removing the stiffening elements. This gradually increases mobility.

**Figure 3.** Bodice "soft orthosis with struts".

**Figure 4.** Corset "Soft orthoses with a rigid part encompass the pelvis".

Back brace with shoulder straps to erect the spine: dorsal struts with shoulder straps to erect the thoracic spine.

Symptomatic osteoporosis and hyperkyphosis in seniors are the most common indication for this treatment (Figure 5) [30].

Spinal orthosis which does not encompass the body to relieve spine: orthoses that do not encircle the trunk in a circular manner. Their aim is correction, especially in the sagittal plane. Thus, the indication for straightening the spine is in the primary focus. Vertebral fracture treatment without significant bony deformity forms the main indication (Figure 6).

**Figure 5.** Back brace with shoulder straps to erect spine.

**Figure 6.** Spinal orthosis to relieve the spine.

Our goal was to derive a treatment concept on the basis of a delineation of the indications for different orthoses.

According to the results of the literature review and classification of spinal orthosis, we made a standardization of indication. A clarification concept of the complaints followed by the orthosis selection depending on anatomical cause of the complaint was an element of the treatment concept.

In Table 3, pain localization is linked to pathology and orthosis selection is based on the anatomical localization and cause of the complaint. Table 3 gives an overview for a basic concept.

The result of a clinical examination is sufficient for the prescription of a bandage. Bandages can relieve pressure through the circular socket and, through the use of pads, provide targeted force application and thus pain relief (Figure 2).

Diagnoses derived from X-ray findings allow segmental assignment. Thus, a segmental force application or change in position of the spine is required to alleviate the symptoms. This correction can be achieved by a bodice (girdle spine support) (Figure 3).

A differentiated diagnosis by means of CT or MRI provides information that can be assigned to segmental anatomical structures. Only wearing a corset can provide the resulting stabilization or change of spine positioning (Figure 4).

In everyday use, there are overlaps between bodices and corsets.

A back brace with shoulder straps is indicated to erect the spine without affecting breathing. A fragile kyphotic spine, especially in elderly people, is the main indication (osteoporosis, metastasis, etc.) (Figure 5).

Spine supports which do not encompass the body are a possible treatment of vertebral body fractures without loss of stability, and support the healing conservatively (according to AO classifications A0 and A1) (Figure 6).

For prevention, wearables have become increasingly available as a training device for postoperative treatment and to avoid discomfort. The line between medical treatment and sports equipment is becoming increasingly blurred.

**Table 3.** Standardization of indication and therapy goals.

