Can HBOT Support CRPS and RSD Pain Management During Pain Awareness Month?

Pain Awareness Month is an opportunity to look at chronic pain conditions that can affect movement, sleep, work, and daily life. Complex Regional Pain Syndrome (CRPS) is one of the more difficult conditions to manage because the pain is often accompanied by changes in sensation, swelling, skin temperature, color, sweating, and movement. CRPS can develop after an injury, fracture, surgery, or other trauma. In some patients, pain continues long after the original injury should have healed. The condition may affect the back, neck, an arm, hand, leg, or foot and can become persistent without appropriate treatment. The term Reflex Sympathetic Dystrophy (RSD) is still used in older medical records and patient discussions. Modern medicine generally uses CRPS-I for cases without a confirmed nerve injury and CRPS-II for cases with a documented nerve injury.

Hyperbaric Oxygen Therapy (HBOT) has been studied as a possible adjunctive treatment for CRPS. The clinical evidence is limited, so the question is not whether HBOT is a cure for CRPS. The more useful question is whether it may help selected patients with specific symptoms while remaining part of a broader pain and rehabilitation plan.

What Is Complex Regional Pain Syndrome?

CRPS is a chronic pain disorder that usually develops in a specific limb after an injury, medical surgery, or procedure. The severity of the pain may be greater than expected from the original injury, and the symptoms can involve several body systems.

Patients may experience allodynia, in which normally harmless touch causes pain, or hyperalgesia, in which painful stimuli feel unusually severe. Swelling, changes in skin color or temperature, abnormal sweating, stiffness, weakness, and reduced movement can also occur.The condition is diagnosed clinically. There is no single blood test or scan that confirms CRPS. Physicians use the patient's history, physical findings, and accepted diagnostic criteria while considering other possible causes of the symptoms. The Budapest clinical criteria are widely used and were developed to improve diagnostic accuracy.

Accurate diagnosis matters because several neurological, vascular, musculoskeletal, and inflammatory conditions can produce symptoms that resemble CRPS.

CRPS-I, CRPS-II, and the Earlier Term RSD

CRPS is generally divided into two types.

CRPS-I occurs without evidence of a specific nerve injury. This form was historically called Reflex Sympathetic Dystrophy or RSD.

CRPS-II occurs after a confirmed injury to a specific peripheral nerve. The older term causalgia was used for this form.

The distinction helps clinicians describe the condition, although both forms can produce severe pain and functional impairment.

Patients may still see RSD written in older medical records or hear the term from healthcare providers who have treated them for many years. Knowing that RSD is an older term for what is now generally classified as CRPS-I can make those records easier to understand.

Why Can CRPS Pain Continue After the Original Injury?

The original injury is only the starting point for many CRPS cases. The ongoing pain appears to involve changes in how the peripheral and central nervous systems process sensory information.

A light touch may become painful. A normally painful stimulus may produce an exaggerated response. Changes in the autonomic nervous system can contribute to differences in skin temperature, sweating, and blood-vessel behavior. Swelling and reduced movement may add further limitations.

Inflammatory and immune-related mechanisms have also been investigated. Current research does not point to one single process that explains every case. CRPS appears to involve several interacting mechanisms, which helps explain why patients can have very different symptoms and why treatment response varies.

This complexity also means that treating CRPS requires more than focusing on pain intensity alone.

Why Is CRPS Management Usually Multidisciplinary?

The main goal of CRPS care is to help the patient regain function while controlling pain well enough to participate in rehabilitation.Physical and occupational therapy are important parts of treatment. Depending on the patient, care may also include medications for neuropathic pain, approaches to reduce swelling, psychological support, sympathetic nerve blocks, or neuromodulation.

The European Pain Federation has established standards covering diagnosis, assessment, pain management, physical rehabilitation, psychological support, and coordinated care.

Recent clinical guidance also emphasizes individualized treatment because CRPS does not behave the same way in every patient. Research across CRPS treatments remains uneven, with many studies involving small patient groups or producing mixed results.

This is relevant to Hyperbaric Oxygen Therapy (HBOT). Any potential role for hyperbaric treatment should be considered alongside established rehabilitation and pain-management strategies rather than in isolation.

Case Study 1: HBOT Outcomes in 83 Patients With Complex Regional Pain Syndrome

A retrospective case series from the Centre of Hyperbaric Medicine Ostrava reviewed 83 patients with CRPS treated with HBOT between 2018 and 2019. Treatments were administered once daily at 2.0–2.4 ATA, with patients receiving an average of about 22 sessions.

Before treatment, pain was reported by 98% of patients, while 92% had limited movement, 87% had limb swelling, and 70% reported sensory problems. At the end of treatment, 86% of the assessed patients reported symptom relief. Average pain at rest decreased from 3.2 to 1.6, while pain during activity decreased from 6.1 to 3.7. Functional assessment of the affected limb also improved, falling from 7.0 to 4.3, with statistically significant changes reported for each measure.

Among the 79 patients included in the final assessment, 23 (29%) had a large clinically significant response and 48 (61%) had a partial response meeting the study's minimally important difference. The researchers also found a stronger treatment effect among patients whose CRPS had been present for three to six months or less. No serious HBOT-related complications were reported in the case series.

The findings suggest that HBOT may have potential as an adjunctive option for selected patients with CRPS, particularly earlier in the course of the condition. However, because this was a retrospective case series without a control group, the results cannot establish that HBOT alone caused the improvements. Further controlled research is needed to determine its effectiveness and the patients most likely to benefit.

For readers who want to examine the research in greater depth, the full case study provides additional details on patient outcomes, HBOT protocols, and clinical findings.

Case Study 2: https://pubmed.ncbi.nlm.nih.gov/39878056/

Case Study 3: https://pubmed.ncbi.nlm.nih.gov/41913797/

What Did the Randomized CRPS Trial Find?

One of the most important clinical studies of HBOT for CRPS was a double-blind, randomized, placebo-controlled trial involving 71 patients.

Thirty-seven patients received HBOT, while 34 received normal air inside a hyperbaric chamber as the control treatment. Both groups underwent 15 sessions. Researchers measured pain, edema, and wrist range of motion before treatment, after the 15th session, and again on day 45.

The HBOT group experienced significant reductions in pain and swelling and a significant improvement in wrist movement. Compared with the control group, the HBOT group had better outcomes for most measured variables, although wrist extension did not show a significant difference.

This trial is important because it used a controlled design rather than simply observing patients who chose HBOT. At the same time, the study involved a relatively small number of participants and evaluated a specific treatment protocol. Its findings therefore provide evidence of possible benefit without establishing HBOT as a universal CRPS treatment.

What Are the Main Limitations of the Evidence?

The biggest limitation is the size and diversity of the available research.

CRPS is relatively uncommon, and patients can differ considerably in disease duration, affected body region, symptoms, and previous treatment. This makes it difficult to enroll large, uniform groups for clinical trials.

HBOT studies also use different treatment schedules and outcome measures. One study may focus on pain and swelling, while another may evaluate movement or functional status. Such differences make it harder to combine results and determine exactly which patients are most likely to benefit.

For these reasons, current evidence supports continued investigation rather than broad claims of established effectiveness.

Could HBOT Be Used Alongside CRPS Rehabilitation?

For a patient being considered for HBOT, the treatment goal should be specific and measurable. A physician may review the duration of CRPS, affected limb, degree of pain, swelling, range of motion, sensory changes, previous therapies, medications, and ability to participate in rehabilitation.

The patient's existing pain-management team can remain involved. This is particularly important because physical rehabilitation remains central to CRPS care. If pain is reduced enough to allow more effective movement or therapy, functional improvement becomes a more meaningful outcome than pain reduction alone.

HBOT should therefore be viewed as a possible adjunctive therapy under medical supervision, not as a substitute for physical rehabilitation, pain management, or other appropriate care.

Closing Thoughts:

CRPS shows why chronic pain cannot always be understood by looking at the original injury alone. The condition can involve changes in sensation, autonomic function, movement, swelling, and pain processing, and its presentation can vary substantially between patients. Research into HBOT has produced encouraging findings. The randomized trial involving 71 patients reported improvements in pain, edema, and wrist movement after treatment. More recent reviews also identify potential benefits while emphasizing the small and varied nature of the evidence base.  That balance matters. HBOT is not established as a cure for CRPS or RSD, and current evidence does not justify replacing standard rehabilitation and pain-management care with hyperbaric treatment. For selected patients, however, it remains an area of clinical research and may be considered as an adjunct after appropriate medical evaluation. At Advanced Hyperbaric Recovery Inc., patients considering medical-grade Hyperbaric Oxygen Therapy can discuss their diagnosis, previous treatment, symptoms, and goals with a clinical team. A physician-directed assessment can help determine whether HBOT has a reasonable role in an individual's broader treatment plan.

For Pain Awareness Month, the most useful message is that CRPS requires careful diagnosis, individualized care, and realistic expectations. Treatment decisions should follow the patient's clinical presentation and the strength of available evidence rather than broad claims about any single therapy.

FAQs:

1. What is Complex Regional Pain Syndrome (CRPS)?

CRPS is a chronic pain condition that can develop after injury or surgery. It may cause severe pain, swelling, sensitivity, temperature changes, and reduced movement in an affected area or limb.

2. Is RSD the same as CRPS?

RSD is an older term for CRPS-I, which occurs without confirmed nerve injury. CRPS-II involves a documented nerve injury and was previously called causalgia.

3. Can HBOT help people with CRPS?

Research suggests HBOT may reduce pain and improve limb function in some patients with CRPS. Current evidence remains limited, so treatment should be individually evaluated and medically supervised if all other traditional care fails.

4. Should HBOT replace standard CRPS treatment?

No. HBOT should not replace established CRPS care. Physical rehabilitation, pain management, and other appropriate treatments remain important parts of an individualized treatment plan. HBOT should only be considered after all other traditional medical care fails. 

5. Does starting HBOT earlier improve CRPS outcomes?

Some research has reported greater clinical improvement among patients treated earlier after CRPS diagnosis. However, stronger controlled studies are needed to determine the effect of treatment timing. HBOT should only be considered after all other traditional care has been tried and fails. For the rare patient who does not respond to normal pathways and/or who has adverse reactions to medications normally used for CRPS treatment. 

If you would like more information or to schedule a comprehensive consultation with one of our Hyperbaric physicians, please call 415-785-8652 now.