Multimodal pain therapy in patients with endometriosis: Care structure in German pain centers

An estimated one in ten women of childbearing age has endometriosis. This equates to around 1.7 million affected women in Germany. There are approximately 40,000 new diagnoses each year (Diedrich et al. 2006). The most important symptom is severe pain during menstruation, but also abdominal pain independent of menstruation. The more severe the pain, the greater the impairment of quality of life (Facchin et al. 2015). Depending on the location of endometriosis lesions, other symptoms, functional complaints, and accompanying complications may occur. Endometriosis is a chronic pain disorder, which often takes several years to diagnose. Furthermore, current treatments result in high recurrence rates, and the cause of the disease remains unclear (Diedrich et al. 2006; AWMF 2020). The long-lasting pain leads to complex neurological changes, which often cause the pain to become chronic (Ball and Khan 2020; Brawn et al. 2014). Pain is defined as chronic if it lasts more than three months or is recurrent (Treede et al. 2019).

>> Improving the quality of life in everyday life through information and self-help, multimodal pain therapy, and low-threshold access to specialized and interdisciplinary support for all affected individuals should be one of the primary goals of endometriosis therapy. Expert recommendations, guidelines, and review articles agree on this (Arnold et al. 2014; As-Sanie et al. 2019; Greco 2003; Glier 2019; Becker et al.). At the same time, researchers (As-Sanie et al. 2019), treating physicians, and patients (Weber et al. 2023) denounce the current
They point to inadequate care for endometriosis patients and call for a holistic treatment approach for endometriosis both in Germany and internationally. Access to multimodal therapy is limited in Germany. The Robert Koch Institute (RKI) care report highlights a care gap: a low number of inpatient rehabilitation programs for endometriosis, and outpatient interdisciplinary disease management programs for endometriosis are unavailable (Robert Koch Institute (RKI) 2020).
Opinions among various experts regarding the content and coordination of cross-sector, cross-intervention, and cross-disciplinary therapeutic approaches for pain management of patients with endometriosis differ. For this study, the definition of Arnold et al. (2009) and the German Pain Society (2014) is used (Arnold et al. (2014; Arnold et al. (2009)): "Multimodal pain therapy refers to the comprehensive treatment of patients with chronic pain syndromes, closely coordinated in terms of timing and content, in which various somatic, physical exercise, psychological exercise, and psychotherapeutic procedures are integrated according to a predetermined treatment plan with an identical therapeutic goal agreed upon by the therapists."
Although multimodal pain therapy is considered the standard of care for patients with chronic pain due to endometriosis, there is little literature on the care structure in Germany (Willimann 2012; Mechsner 2021a, 2021b; Maass and Janni 2015; Kayser et al. 2022; Carl 2021).
This study examines the current care structures for endometriosis patients in German pain centers. The aim is to analyze the specific challenges in the care of patients with endometriosis from the perspective of pain centers. Furthermore, the therapeutic needs regarding pain therapy for endometriosis patients are identified. Furthermore, an overview of the treatments used in pain centers for multimodal pain therapy of patients with endometriosis, as well as their reimbursement structures, is provided.
methodology
Study design
This study conducted an online survey and expert interviews. The online survey was conducted using the SoSci Survey web application. The expert interviews were conducted by the authors (Charlotte Weber, Teresa Götz, Roman Spelsberg) by telephone or online and were conducted separately from the online survey. The semi-structured interview guide was based on initial results of the online survey and was provided to the experts prior to the interviews.

recruitment
Recruitment for the study took place online from August 1, 2023, to September 30, 2023. Pain centers were contacted through participating experts and institutions, as well as professional societies and publicly available contact information. Invitations to participate in the study, including a link to the online survey, were sent to the pain centers via email. All participants were informed about the study objectives and the anonymity of their data and received contact information for the study director.

study population
Pain centers offering multimodal pain therapy (outpatient, day-care, or inpatient) were included in the study. They were located in Germany and had internet access and the motivation to complete the online survey. The exclusion criterion was lack of consent to participate in the study.
The study population for the expert interviews consisted of a subset of experts who had received an invitation to the online survey by email or who had participated in it. Following the online survey, the experts were able to indicate their willingness to participate voluntarily in the expert interviews.

Evaluation
To evaluate the quantitative questions of the online survey, descriptive analyses were conducted using SPSS. These included the number of responses as well as the maximum, minimum, median, and mean values of the responses on the rating scales.
Mayring's summary content analysis (Mayring 1994) was used to evaluate the expert interviews. This analysis was conducted by authors who were not involved in the interviews.
Results
Between August 4 and September 13, 2023, 294 German pain centers were contacted. Nineteen experts from pain centers participated in the online survey, 10 of whom completed the questionnaire in full. In addition, nine experts participated in interviews.
Some of the interviewees had previously participated in the online survey. All nine interviewees had completed specialist training in a relevant field. Eight of the nine interviewees had completed specialist training in anesthesiology with the additional designation in specialized pain therapy. Seven of the nine experts held senior physician or other management positions. Four of the participants worked in university institutions, three in non-university clinics, and two in outpatient pain centers.
In the online survey, the experts at the pain centers (N = 10) reported caring for an average of 206 pain patients per quarter (SD = 144.9), of which an average of 5.9 were endometriosis patients (SD = 2.6). 83.1% of the pain patients in the surveyed centers are covered by statutory health insurance (SD = 28.2%).
Procedure for multimodal pain therapy in endometriosis patients
Figure 1 schematically depicts the treatment process of endometriosis patients treated in pain centers based on the study results and a systematic literature review.
Various procedures are used to make the diagnosis. Initially, unimodal pain management measures are applied. Regarding the diagnosis, both the online survey and the expert interviews addressed the excessively long diagnosis time for endometriosis due to gaps in care. The experts also agree that the treatment path to multimodal pain therapy for endometriosis needs to be significantly shortened. During one of the expert interviews, one expert commented: "I think women come far too late, and most of them come when they are no longer able to work. That's a shame, because a regular daily routine, a certain amount of recognition, appreciation, and meaning are part of coping with and managing the illness, and self-efficacy."
One problem is the visibility of endometriosis patients in pain centers. In both survey modalities, experts report that approximately half of the patients who are also treated for symptoms of endometriosis receive a different primary diagnosis. The primary diagnosis and referral diagnosis is usually chronic pain disorder with physical and psychological factors (F45.41). This can prolong the time until the necessary specific treatment is initiated.
Both the online survey and the expert interviews show that pain therapy treatment processes vary depending on the center, clinic, or practice. The initial step is usually an assessment, including evaluation of the German Pain Society's pain questionnaire. Medicinal and non-medicinal measures are applied with a holistic approach to the patient, strengthening individual resources and creating a salutogenic counterbalance to the burden of illness and providing pain relief.
According to the experts interviewed, multimodal pain therapy in the narrower sense involves forming a team comprised of representatives from the relevant disciplines. Coordination is carried out by medical staff. A team typically cares for a group of approximately eight patients. The duration of therapy is individualized and, in this outpatient/outpatient setting, ranges from approximately one to five weeks, with inpatient stays being shorter than outpatient stays. A minimum duration of three weeks is aimed for sustained therapy effectiveness. During this time, the therapy components are continuously adapted to the patient's needs.
According to most of the experts interviewed, a follow-up appointment takes place approximately six months after the end of the stay, in which the individual's success in everyday life is discussed and, if necessary, adjustments to the measures are made.
At the end of multimodal treatment, an individualized therapy plan is developed that should be followed up. The success of the subsequent connection depends on a variety of circumstances, such as location, age, or comorbid psychiatric conditions. Pain centers strive to assist in connecting patients with suitable specialists, but long wait times are often still encountered.
The core goal of multimodal pain therapy is to improve quality of life by empowering patients to individually design self-help measures that they can continue independently in their daily lives (e.g., sleep hygiene, regular exercise).
However, this objective of the experts often does not correspond to the reality of care. Instead of receiving individually tailored multimodal pain treatment, many endometriosis sufferers are left alone with their pain or, for example, undergo a second operation after an already unsuccessful one, with the same result.
Content of multimodal pain therapy in endometriosis patients
The core components of multimodal pain therapy are pain medicine, psychosomatics/psychotherapy education/therapy, and physiotherapy. According to experts, these core components should be supplemented by a variety of other treatment options, such as nutritional therapy or music therapy, tailored to each patient's individual needs.
Both the online survey and the expert interviews reveal a wide range in the frequency of individual therapy options, as each option is designed to be tailored to the individual patient in terms of design and frequency. A mix of group and individual treatments is mentioned.
There are no guidelines for the treatment of endometriosis-related chronic pain, but as part of the individual therapy design for endometriosis patients, a special therapeutic focus is placed on the pelvic and lower abdominal area as well as the endometriosis-specific symptoms.
Interdisciplinary collaboration is crucial for multimodal pain therapy. Eleven centers responded to the question about providers involved in interdisciplinary treatment sessions for interdisciplinary, multimodal pain therapy for endometriosis patients (see Figure 2). Other providers listed in the free text were: "osteopath," "internal medicine specialist," "physician in physical medicine," and "nutritionist."
In the expert interviews, multimodal pain therapy is also distinguished from other forms of therapy by its intensive interdisciplinary collaboration. The mix of diverse options and the individual adaptation of this holistic approach are seen as therapeutic advantages. Another advantage cited is the comparatively longer duration of individual appointments, which is often lacking in other settings to do justice to the complexity of the disease.
A key theme of the expert interviews is the need for multimodal therapy options outside of inpatient treatment. The majority of multimodal pain therapy currently takes place in inpatient settings. Outpatient care is currently limited to nonexistent, partly because it is currently not cost-effective. Reimbursement for multimodal pain therapy in the narrow sense only covers the resulting costs in the case of partial or inpatient admission and reimbursement through daily or case-based flat rates.
Multimodal therapy options outside of inpatient treatment are very attractive to many patients due to their local commitments and could be utilized by a larger number of people. They could provide a broader range of treatment options and be applied earlier and preventively, before pain becomes chronic. This contrasts with inpatient treatment, which is often only initiated when pain has advanced and symptoms are severe, when the prospects for treatment success have already significantly deteriorated. Therefore, from an expert perspective, multimodal therapy options outside of inpatient treatment are desirable, but they fail not only due to remuneration but also due to functional concepts, the necessary specialists, and close interdisciplinary coordination.
Billing for multimodal pain therapy in endometriosis patients
Although multimodal pain
Although experts consider multimodal pain therapy to be the standard of care for endometriosis patients with chronic pain, a gap in care exists. This is due not least to the billing situation. As in other disease areas, care is dependent on reimbursement. While there are established billing modalities for multimodal pain therapy in inpatient and day-care settings (see Table 1 and Table 2), billing options in the outpatient setting are inadequate. The experts point to the potential of outpatientizing multimodal pain therapy for endometriosis patients. Where billing options were identified in the outpatient setting, attempts were made to characterize them, always emphasizing the individualized nature of the therapy, which must be the top priority of multimodal therapy (see Table 3).
As part of the care provided in university outpatient clinics or pain
In outpatient clinics, a portion of the services of multimodal pain therapy are billed via flat-rate fees. In an exemplary case, this flat rate amounts to 150 euros per patient per quarter. This covers basic pain management care, consisting of assessment, therapy planning, and therapy education. Services for physiotherapy and psychotherapy are not included in this flat rate and are billed separately. These services are billed according to the Uniform Assessment Standard (EBM). Furthermore, care contexts were described in which the core services of multimodal pain therapy are coordinated in a medical care center (MVZ) and billed according to the EBM. Following an initial assessment with up to 5 trial sessions, this outpatient care offers a three-week therapy program consisting of at least 12 units of physiotherapy, 6 sessions of behavioral therapy, 4 consultation appointments, and additional treatment options tailored to the individual patient. In addition, 4 pain therapy case conferences are held to coordinate treatment.
challenges
The online questionnaire presented 15 hypotheses regarding the treatment of patients with endometriosis in Germany, which could be rated on a scale of 1 ("agree") to 5 ("disagree"). The results are presented in Table 4.
Overall, the experts surveyed see major gaps in the treatment of endometriosis patients in Germany.
In both survey modalities, the often very advanced chronicity of the patients is addressed as a challenge. Multimodal pain therapy is often used as a last resort after various other therapies have failed. Preventive therapy to prevent pain chronicity is cited as the ideal treatment. However, since there are currently no resources available for such prevention, it is considered one of the greatest challenges and gaps in care.
The expert interviews also address the need to raise awareness among gynecologists and general practitioners about pain in women, interdisciplinary collaboration, and multimodal pain therapy in order to improve care.
The care situation varies regionally and is particularly critical in rural areas. One expert notes: "I don't believe that pain centers can generally meet the demand." Another expert explains: "There are certainly areas where sufficient capacity exists. And then there are areas where there is no pain therapy center at all."
This affects access to multimodal pain therapy and follow-up treatment. Identified treatment concepts often cannot be implemented. Waiting times are often longer than six months. The shortage of skilled workers, particularly among psychotherapists and psychosomaticists, poses a challenge for care both within and outside of multimodal pain therapy. Furthermore, current care is not geared towards endometriosis-related chronic pain and focuses on the most common chronic pain conditions, such as chronic back pain.
Finally, the media attention given to endometriosis is addressed. On the one hand, this increases patients' awareness. On the other hand, there is still a lack of understanding of the topic of "pain" and the associated burdens in society. Nevertheless, a dramatic portrayal of the disease should be avoided. The experts recommend transparent, competent, and encouraging information.
discussion
This study demonstrates the importance of interdisciplinary, multimodal pain therapy for endometriosis patients, both curatively and preventively (Mechsner 2021a; Pickett et al. 2023). Key to treatment success is finding individually tailored strategies for each patient that can be applied in everyday life (Kieselbach et al. 2022). Multimodal pain therapy is considered the standard of care. However, this does not reflect the reality of care; instead, gaps in care exist. Various factors play a role.
Availability poses a major challenge in many regions of Germany. A shortage of skilled workers is often a problem (Mechsner 2021a). Current reimbursement structures sometimes hamper or even prevent adequate pain therapy for endometriosis patients (Mechsner 2021b). General practitioners and gynecologists are often under-informed and only refer patients for multimodal pain therapy after significant chronification. This, along with the long duration of diagnosis, leads to inadequate care, especially for patients with subchronic pain (Kieselbach et al. 2022; Mechsner 2021b). In addition, misdiagnoses can delay appropriate treatment.
(Mechsner 2021a).
Experts see an important approach to closing the gaps in care in the expansion of preventive measures to prevent pain from becoming chronic. In the long term, this could reduce costs in the healthcare system, which are currently incurred, for example, by multiple surgeries and long periods of incapacity for work in endometriosis patients. This could be possible, for example, in a step-by-step approach in which treatment is tailored to the severity and type of pain as well as the overall disease situation (Mechsner 2021b, 2021a). Digital concepts that can be used by a larger number of sufferers, even in the early stages of pain, could be part of this step-by-step approach. This is in line with experts' recommendations for expanding multimodal pain therapy outside of inpatient treatment, as in the outpatient sector, chronic pain patients are currently often under- and inadequately treated due to a lack of reimbursement, functional concepts, and the necessary specialists (Mechsner 2021a; Kieselbach et al. 2022).
limitations
The study uses various operations, online survey and expert interviews, to mutually validate the subjective data using a triangulation convergence model.
A limitation of the study is the low response rate from the contacted pain centers and the resulting small study sample. Furthermore, participants were not randomly selected; rather, self-selection by experts interested in the topic of endometriosis cannot be ruled out. Furthermore, qualitative expert interviews are always subject to the selective and subjective opinions of the respondents. Finally, the perspective of those affected on their care situation was not captured and should be analyzed in future studies.