The committee discussion (in 2018) was on iFuse with the original titanium plasma spray coated implants, which is likely to be clinically equivalent to iFuse-3D. [2022]
The committee recognised the uncertainties in the published evidence but concluded that using iFuse to treat chronic sacroiliac pain is likely to lead to less pain, reduced disability and a better quality of life compared with non-surgical management.
The committee heard from a patient expert adviser who had complete pain relief soon after having iFuse implanted. They explained that iFuse had had a transformative effect on their life; after treatment, they were able to return to daily activities without being restricted by chronic pain. The clinical expert advisers confirmed that this accurately reflected the experience of their own patients who had iFuse implanted. The committee concluded that using iFuse could lead to considerable clinical benefits for people with chronic sacroiliac joint pain.
The clinical expert advisers explained that people with sacroiliac joint pain are generally offered non-surgical management, with only a few centres offering sacroiliac joint fusion. When joint fusion is an option, minimally invasive techniques are usually preferred. The clinical expert advisers explained that open surgical sacroiliac joint fusion is not normally done because it is a technically challenging procedure that is associated with long recovery times, high revision rates and poor long-term results. The committee therefore concluded that non-surgical management was the most appropriate comparator in standard NHS practice against which iFuse should be assessed.
The clinical and patient expert advisers explained that chronic sacroiliac joint pain is an extremely debilitating condition that can restrict daily activities, affect mood and impair sleep. People with chronic sacroiliac joint pain are therefore likely to need strong analgesic medication that may include regular doses of opioids. People may also be offered steroid joint injections; the patient expert adviser explained that these injections are associated with a recovery period before discharge, such that they often involve taking time off work or away from other responsibilities. The clinical expert advisers explained that steroid joint injections may be done every 6 months, but that the effects often last for only around 3 months. This can lead to some patients having a recurrence of chronic pain after a period of relief. They also noted that some commissioning bodies may not fund ongoing and repeated steroid injections. The committee also heard from the expert advisers that radiofrequency ablation is of limited therapeutic benefit. It concluded that chronic sacroiliac joint pain is generally managed with non-surgical treatments that are associated with potential side effects, patient inconvenience, and recurrent and inadequately controlled symptoms.
The clinical expert advisers explained that chronic sacroiliac joint pain typically affects adults in middle age and that it is more common in women. Most patients are younger than 60 years, so face living with recurring symptoms over many years. The clinical expert advisers explained that chronic sacroiliac joint pain may result from inflammatory conditions affecting the joint, previous pelvic trauma (including from childbirth) and the transmitted shear stresses associated with previous spinal fusion. Some inflammatory conditions may resolve over time or with medication, so joint fusion procedures may not always be appropriate. The clinical expert advisers stated that they would not recommend using iFuse in people with osteoporosis in the bone adjacent to the sacroiliac joint, because this would increase the risk of device instability and incomplete joint fusion. However, they noted that once iFuse is implanted and the joint has fused, the risk of device and joint instability is low.
The clinical expert advisers explained the importance of an accurate diagnosis of chronic sacroiliac joint pain before iFuse is considered (that is, confirmation that the pain originates from sacroiliac joint dysfunction). The diagnosis needs to be confirmed by injecting local anaesthetic into the joint under image guidance. If the signs and symptoms are characteristic and the local anaesthetic joint injection provides pain relief, a diagnosis of chronic sacroiliac joint pain can be confirmed. MRI and CT scanning may also provide useful diagnostic information, particularly in people with multiple back issues.
The clinical expert advisers stated that sacroiliac joint pain is often misdiagnosed as pain originating from the lumbar spine or hip joint, and that sacroiliac joint dysfunction may sometimes not be considered as the cause for back pain. The patient expert adviser explained that this was reflective of their own experience. The committee concluded that sacroiliac joint pain is likely to be underdiagnosed, and an increased awareness of the condition among clinicians when assessing and treating low back pain would be beneficial.
Implanting iFuse is a technically challenging procedure during which there is a risk of damaging nerve roots and blood vessels adjacent to the sacroiliac joint. The company provides relevant and necessary training. The clinical expert advisers described the importance of taking part in training courses and in first doing the procedure under the supervision of a trained and experienced surgeon.
The committee noted that the company had submitted 2 models, 1 of which compared iFuse with open surgery. Having acknowledged that open surgical sacroiliac joint fusion is rarely done, the committee concluded that this model was not relevant to current NHS practice. It instead focused on the model that compared iFuse with non-surgical management.
The committee agreed with the changes the external assessment centre (EAC) had made to the company's cost model comparing iFuse with non‑surgical management. The clinical expert advisers confirmed that the assumptions used in the cost models were representative of their experience with iFuse. For example, the model assumed that an overnight stay in hospital would usually be needed after having iFuse implanted, and that 3 (or occasionally 2 or 4) implants are used per joint treated. The expert advisers explained that single joint procedures are more common, but that some patients with bilateral disease may need a second procedure in the opposite joint months or years later. Around 60% of people have pain in both sacroiliac joints, but symptoms are usually more severe in 1 joint. The clinical expert advisers explained that standard practice would be to treat the joint with the most severe pain first, and then observe the treatment response before deciding on whether to use iFuse for the other joint.
The committee discussed the additional modelling by the EAC, which extended the time horizon to 30 years. The clinical expert advisers stated that most people with chronic sacroiliac joint pain will have repeated steroid joint injections (up to 3 a year) but that the injections will become less effective over time. They explained that it is unlikely anyone would have repeated steroid joint injections for up to 30 years because of the nature of the procedure and their reducing efficacy with time. After 30 years, people will have exhausted all other non-surgical management options and are likely to have to rely on analgesic medication alone. The committee noted that this was reflected in the longer 30‑year time horizon implemented by the EAC, but the rate at which steroid injections decreased was based on informed opinion because no data were available.
The committee considered the longer time horizon to be appropriate and that it provided additional information but recognised that it introduced uncertainty. Nonetheless, the experts predicted that the long-term performance of iFuse is likely to be good and that the risk of fracture or need for revision is low. They explained that any revisions are usually needed in the first few years after implantation; after this, the bone grows over the implant and across the sacroiliac joint, creating a permanent fusion that is stronger than the original joint and the surrounding bone. A company representative stated that the first iFuse devices were implanted in 2010 and that there are, to date, no reports of device failure after 2 years. The committee considered it plausible that iFuse may permanently relieve the symptoms of chronic sacroiliac joint pain. The committee concluded that after 8 years, using iFuse instead of non‑surgical management could save around £129 per patient. It is likely after 8 years, these savings will increase over time to provide further value to the NHS.
Results for the 2022 updated model shows iFuse is cost incurring up to 8 years (by £323) before becoming cost saving from year 9 (by £230.37). iFuse-3D becomes cost saving from year 10 (by £172.31) onwards. [2022]