[Joint DGN, OGNMB and SGNM S1 guideline for radiosynoviorthesis]

[Pain reduction by radiosynoviorthesis in rheumatism-induced synovitis of the elbow : Results of a retrospective multicenter data analysis]

BACKGROUND

Radiosynoviorthesis (RSO) is a nuclear medical local treatment modality for inflammatory joint diseases. It is indicated in patients with rheumatoid arthritis (RA) in joints with persistent synovitis despite adequate pharmacotherapy. Arthritis of the elbow joint occurs in up to 2/3 of patients with RA. Intra-articular radiotherapy using the beta emitter [186Re] rhenium sulfide leads to sclerosis of the inflamed synovial membrane with subsequent pain alleviation. The clinical efficacy in cubital arthritis, however, has so far only been described in small monocentric studies.

OBJECTIVE

The degree of pain alleviation by RSO was analyzed in patients with rheumatoid cubital arthritis, treated in several nuclear medical practices specialized in RSO.

MATERIAL AND METHODS

The subjective pain intensity before and after RSO was documented in a total of 107 patients with rheumatic cubital arthritis using a 10-step numeric rating scale (NRS). A difference of ≥ -2 is rated as a significant improvement. Follow-up examinations were done after a mean interval of 14 months after RSO (at least 3 months, maximum 50 months).

RESULTS

The mean NRS value was 7.3 ± 2.1 before RSO and 2.8 ± 2.2 after RSO. A significant pain alleviation was seen in 78.5% of all patients treated. The subgroup analysis also showed a significant improvement in the pain symptoms in all groups depending on the time interval between the RSO and the control examination. A significant pain progression was not observed. The degree of pain relief was independent of the time of follow-up.

CONCLUSION

Using RSO for local treatment of rheumatoid cubital arthritis leads to a significant and long-lasting pain relief in more than ¾ of the treated patients.

[Radiosynoviorthesis of the thumb's carpometacarpal joint]

Radiosynoviorthesis (RSO) is an established therapeutic method for the local treatment of pain in aseptic joint inflammation (e.g. arthritis, activated osteoarthritis, synovitis). RSO can be used for the treatment of synovial membrane inflammation of the finger joints such as the thumb's carpometacarpal joint. The beta emitter Erbium-169 (Er-169) is injected into the joint space, which irradiates the inflamed synovialis, thereby leading to fibrosis and obliteration of the pain receptors of the synovial membrane. The chances of success in the treatment of the thumb's carpometacarpal joint by RSO are estimated to be 54-100% within 2-6 weeks after therapy.

[The Baker's cyst - a blunt sword of Damokles in radiosynoviorthesis (RSO)?]

The existence of a popliteal Baker's cyst was regarded as a contraindication for radiosynoviorthesis of the knee joint since decades. A so-called "ventile mechanism" was discussed leading to a significant concentration of the intraarticularly applied, high energy beta emitting radiopharmaceutical yttrium-90-colloid in the cyst. This cyst arises from a bursa beneath the tendon of the medial head of the gastrocnemius muscle, normally communicating with the knee joint space. Since the cyst wall is much thinner than the knee joint capsule, a radiogenic rupture of the cyst was feared, leading to severe radiogenic necroses of the surrounding soft tissue. Due to this potential hazard, knee joint ultrasound is mandatory prior to radiosynoviorthesis to check for any popliteal cysts. New studies however decline the risk of a radiogenic cyst rupture after an appropriately performed radiosynoviorthesis of the knee joint.In case of a preexistent cyst rupture, the risk of a radiogenic tissue damage remains an issue and magnetic resonance imaging (MRI) is the method of choice to exclude this potential hazard. However, MRI sometimes leads to equivocal results. Scintigraphy of the knee joint after intraarticular application of Tc-99m-nanocolloid offers the possibility to check for the integrity of the Baker's cyst in these patients to be sure that radiosynoviorthesis will not lead to a relevant extraarticular leakage with soft tissue necroses. This study describes the procedure of intracavitary distribution scintigraphy by means of representative case reports.

The EANM guideline for radiosynoviorthesis

Purpose

Radiosynoviorthesis (RSO) using the intraarticular application of beta-particle emitting radiocolloids has for decades been used for the local treatment of inflammatory joint diseases. The injected radiopharmaceuticals are phagocytized by the superficial macrophages of the synovial membrane, resulting in sclerosis and fibrosis of the formerly inflamed tissue, finally leading to reduced joint effusion and alleviation of joint pain.

Methods

The European Association of Nuclear Medicine (EANM) has written and approved these guidelines in tight collaboration with an international team of clinical experts, including rheumatologists. Besides clinical and procedural aspects, different national legislative issues, dosimetric considerations, possible complications, and side effects are addressed.

Conclusion

These guidelines will assist nuclear medicine physicians in performing radiosynoviorthesis. Since there are differences regarding the radiopharmaceuticals approved for RSO and the official indications between several European countries, this guideline can only give a framework that must be adopted individually.