A thorough history of the RA including severity and duration of the disease, drug treatments and systemic complications should be taken, and meticulous assessment of the airway should be performed. Screening for the cardiovascular complications described above, especially heart failure, should be carried out. A summary of potential difficulties is summarised in Table 5.
Table 5. Anaesthetic concerns in patients with rheumatoid arthritis.
|Increased cardiovascular risks in those with:|
| Seropositive disease (RhF, ACPA)|
| Symptoms of heart failure|
| Poorly controlled disease|
| ‘Rheumatoid cachexia’|
|Likely pre-existing anaemia; increased requirement for red-cell transfusion|
|Very fragile skin; extreme care required when handling and positioning|
|Deformities and fixation of joints can make positioning, especially pronation, difficult|
|Patients are often in considerable pain; care required during examination and anaesthetic preparations, e.g. ‘shaking hands’|
|Poor peripheral venous access; arterial and central venous access are often difficult|
|Airway management may be difficult|
|Glucocorticoid supplementation is required if on long-term steroid therapy|
|Risk of higher than expected spinal block|
|Risk of post-extubation oedema due to cricoarytenitis|
|Postoperative ventilation may be required for those with severe myopathy who are at risk of respiratory failure|
|Possibility of peri-operative neurological damage|
Care should be taken when examining rheumatoid patients who are often in pain and suffer with deformities that restrict simple movements (pronation, shaking hands) and fragile skin. The anaesthetist should note which movements are particularly difficult or painful and anticipate how this may affect positioning when performing procedures peri-operatively (e.g. intravascular access and regional nerve blocks) to minimise injury and discomfort. Involvement of the joints of the wrists and fingers also has implications for the postoperative analgesic plan, as the use of standard patient-controlled analgesia (PCA) may not be a realistic option.
General examination of the patient beyond the cardiovascular and respiratory systems should look for active synovitis in the affected joints. The body mass index should also be noted, as it may indicate rheumatoid cachexia, and poorly controlled disease is associated with an increased long-term cardiovascular risk. Cachexia and poor muscle bulk may also indicate myopathy which may impair respiratory muscle function, and such patients may need to be considered for postoperative mechanical ventilation.
Adequate airway assessment is essential. Patients with RA requiring cervical spine surgery have a high prevalence of grade-3 or -4 laryngoscopy. The Mallampati score and mandibular protrusion (Table 6) both have a high positive predictive value, but may miss up to half the difficult cases. Plain flexion and extension lateral radiographs, looking for C1/C2 joint space loss, better predicts difficult laryngoscopy in these cases .
Table 6. Classification of mandibular protrusion.
|A||Anterior to upper incisors|
|B||Edge to edge with upper incisors|
|C||Posterior to edge of upper incisors|
Symptoms of AAS associated with RA may include neck pain radiating to the occiput and tingling, paraesthesia or numbness of the shoulders and/or arms. It is, however, primarily a radiological diagnosis. Acute subluxation due to neck manipulation can lead to quadriplegia or sudden death due to compression of the spinal cord or vertebral arteries . In the presence of neurological symptoms, patients should be referred to a rheumatologist or spinal surgeon as current opinion favours early fixation. A flexion/extension CT or MRI should be considered, especially if symptoms are associated with severe pain, in the presence of neurological signs or if there is significant abnormality noted on plain X-ray films. However, AAS may be asymptomatic and, even in the presence of suggestive symptoms, it can only be demonstrated by radiological evaluation.
The risks of AAS are dependent on the subtype of instability (see Table 7). The most common subtype (anterior AAS) is worsened by C1/C2 flexion, and therefore direct laryngoscopy should be tolerated. In anterior AAS, C1 and the head tend to move as a unit, so that subluxation is worsened by the head moving anteriorly whilst the upper cervical spine is left behind, e.g. putting a pillow behind the head. A useful technique is to keep the upper cervical spine supported whilst the head is not moved anteriorly, e.g. using a doughnut head ring with a large enough hole to accommodate the occiput . This type of head support, which supports the cervical spine without anterior translation of the head, is a logical choice for rheumatoid patients. Posterior or vertical AAS both pose the risk of spinal cord compression during C1/C2 extension, the movement of which occurs during direct laryngoscopy, which should therefore be avoided. They are, however, much less common than anterior AAS, and are very rarely asymptomatic. Subluxation can also occur due to bony erosion and ligament damage at sub-axial levels: the ‘staircase spine’. Spinal canal stenosis is another possible complication, causing myelopathy due to pannus formation in the spinal canal.
Table 7. Subclassification of atlantoaxial subluxation.
|Anterior||80%||C1 moves anteriorly on C2 |
Destruction of transverse and apical ligaments
|> 3 mm gap between odontoid peg and arch of atlas on lateral flexion film|
|Posterior||< 5%||C1 moves posteriorly on C2 |
Destruction of odontoid peg
|Loss of odontoid peg on lateral flexion film|
|Vertical||10–20%||Odontoid peg translocates through the foramen magnum |
Destruction and erosion of lateral masses of C1 and C2
|> 4.5 mm migration of odontoid above McGregor line (from hard palate to base of occiput) on lateral film|
|Lateral/rotatory||5–10%||Lateral or rotational movement of C1 with respect to C2 |
Degenerative changes at the C1/C2 facet joints
|> 2 mm of loss of lateral alignment of C1/C2 via frontal, open-mouth odontoid film|
|Subaxial (below C2)||Rare||Lateral movement of any vertebra below C2 |
Facet joint degeneration
|> 2 mm loss of lateral alignment on frontal PA films. |
‘Staircase spine’ if at multiple levels
The extent of neck flexion and extension should be assessed and documented, with the aim of avoiding exceeding this range peri-operatively. In practice, however, this is difficult to do accurately as clinical methods are unreliable and anaesthetists are not accustomed to using specialised devices e.g. geniometers. Although neck rotation does not have important implications regarding airway management, excessive rotation may worsen lateral AAS. If present, a history of cervical fixation should be elicited, as cervical fixation devices may cause impaired cervico-cranial extension. It is also worth noting that patients who have had atlantoaxial fixation may have a significantly decreased C1-T1 rotation angle .
The Bellhouse technique (angle from the neutral head position to extreme extension, without moving the neck) of assessing the occipito-atlanto-axial (OAA) extension capacity may be unreliable due to compensatory subaxial extension, which may mask underlying pathology of the OAA complex . One study has found the hyo mental distance ratio (difference between hyo mental distance in extended and neutral head positions) to correlate well with OAA capacity .
There are no published evidence-based guidelines or general consensus on the need to obtain cervical spine X-rays before surgery in asymptomatic patients. The arguments for and against the routine use of this investigation are listed in Table 8.
Table 8. Competing arguments for pre-operative cervical radiographs in rheumatoid arthritis.
|Asymptomatic subluxation is common ||Decline in the incidence and severity of cervical instability and associated neurological involvement in recent years |
|Flexion/extension radiographs good predictors of difficult direct laryngoscopy ||No difference in anaesthetic management of patients with or without cervical instability. No reported neurological complications |
|No standard ‘safe’ head position – the ‘protrusion position’ may reduce atlanto-dental interval in anterior AAS, but may worsen posterior subluxation ||Seventy-seven rheumatoid patients underwent 132 operations. A third of the pre-operative cervical spine X-rays were inadequate or of limited diagnostic value |
|Proven instability on radiographs alters anaesthetic management by reducing neck manipulation ||Serial cervical radiographs over the past 2 years in 14 patients with craniocervical instability showed no progression |
|Incidence of AAS progresses over time, rising fourfold after the third decade. Serial X-rays may show disease progression regardless of findings on previous films ||May delay surgery, expose patients to unnecessary radiation and not alter management|
Temporomandibular joint involvement can make direct laryngoscopy very difficult. This can be assessed pre-operatively using the Mallampati score, mouth opening and mandibular protrusion.
As discussed above, cricoarytenoid arthritis is variable in frequency, intermittent and often unrecognised. Patients have both joint and soft tissue swelling, so that the overall effect is of stenosis. Symptoms may include hoarseness, stridor, a sense of pharyngeal fullness when speaking and swallowing or dyspnoea. Secondary infection of the upper respiratory tract may worsen any swelling/stenosis and tracheostomy may be required [51, 52]. A pre-operative nasendoscopy is advisable if there is any suspicion of involvement, and consideration given to:
- 1 Using a facemask or supraglottic airway device.
- 2 Using the smallest internal diameter tracheal tube possible.
- 3 Avoiding trauma at intubation.
- 4 Considering the use of an airway exchange catheter at extubation.
- 5 Extubating in a suitable environment and at the appropriate time (obstruction often develops some time after extubation).
- 6 In severe cases, a pre-operative tracheostomy may be required.
Other considerations and investigations
Anaemia is common and may be due both to anaemia of chronic disease (normocytic, normochromic) and from treatment toxicity (gastrointestinal haemorrhage, myelosuppression). Patients with RA are therefore more likely to require perioperative blood transfusion.
An electrocardiogram should be performed to check for left ventricular hypertrophy and conduction disturbances. An echocardiogram with a reported normal ejection fraction may be falsely reassuring. Requests to perform this study should ask specifically for evidence of diastolic dysfunction, left ventricular hypertrophy and valvular abnormalities. Diastolic dysfunction may be suggested by the echocardiographic analysis of the E:A ratio which relates to the relative proportion of ventricular filling during early diastole (E) or following atrial contraction (A) measured at the level of the left ventricular inflow or mitral valve annulus. In diastolic dysfunction, there may be an increase in the atrial component (high A peak, reversed ratio) or rapid fall in the E peak. In addition, there may be an enlarged left atrium (in the absence of atrial fibrillation or mitral valve disease), and inspection of the ventricular myocardium in early diastole should be performed to assess its recoil as measured by tissue doppler.
There should be a low threshold for ordering respiratory investigations (e.g. chest radiographs, arterial blood gases and lung function tests with flow volume loops) due to the possibility of pulmonary involvement (fibrosis, nodules, effusions) or respiratory myopathy.
Most studies have suggested that methotrexate can be continued in the peri-operative period without impaired wound healing or a substantially raised risk of peri-operative infection. Furthermore, good disease control in the peri-operative period is beneficial. Unfortunately, there is lack of data regarding the use of other immunosuppressants; however, knowledge of available therapy and its possible side effects should be weighed against the risk of flare-up for each patient .
Peri-operative discontinuation of biological therapy for elective surgery remains controversial. A study in 2006 showed that the peri-operative use of anti-TNF agents was associated with a high incidence of postoperative infections . However, a more recent study suggested that their use does not cause specific adverse effects and may improve recovery from postoperative anaemia . An immunisation history for pneumococcal and influenza vaccines should be recorded for patients on biological or combination therapy.
Choice of anaesthetic technique will depend on the patient’s general condition, type of surgery, patient preference and anaesthetic skill. Regional anaesthesia, general anaesthesia or a combination of the two may be employed.
Regional anaesthesia, if feasible, should always be considered, as it minimises neck movement and avoids airway manipulation. It also provides good postoperative pain relief and reduces polypharmacy. Regional blocks, however, may be technically difficult due to severe lumbar and thoracic spine arthritis and loss of anatomical landmarks from contractures or deformities. Furthermore, if surgery is prolonged, positioning of the patient may be uncomfortable and the operation may outlast the duration of anaesthesia.
For patients undergoing spinal anaesthesia, a higher than normal block should be anticipated. In a recent study, subarachnoid injection of plain bupivacaine in rheumatoid patients resulted in the mean spread of sensory block 1.5 segments higher than in patients without the disease .
If a general anaesthetic is indicated and considered appropriate, there are several options for managing the airway depending on the patient and the type and duration of surgery.
Laryngeal mask airways (LMAs) and other supraglottic airway devices have the advantages of requiring minimal neck manipulation for insertion and causing relatively little trauma and subsequent laryngeal oedema compared with a tracheal tube. They may, however, be difficult to insert in patients with fixed flexion deformities of the neck, in which case a reinforced LMA may be more appropriate.
Tracheal intubation may be indicated depending on the patient’s size, aspiration risk and the type and length of surgery. There are several reasons why a difficult intubation may be encountered and should be anticipated, as discussed above.
If tracheal intubation is indicated, neck manipulation should be minimised, ideally with manual, in-line stabilisation, even if there is no overt cervical spine instability. To date, there are no case reports of spinal cord injury secondary to direct laryngoscopy, nor is there any evidence of outcome difference with a particular technique. Furthermore, intubation is inevitably followed by a variety of other hazards to cervical stability, thus confounding the risks of laryngoscopy alone in patients who suffer subsequent neurological deterioration. However, lack of evidence does not mean that the phenomenon does not exist .
The intubating LMA could be used to aid intubation with minimal neck manipulation. However, the risk of failure and associated trauma to the airway limit its widespread use.
Fibreoptic intubation is considered the appropriate and safer option in rheumatoid patients with an anticipated difficult airway or known cervical spine instability. It generally carries less risk of major difficulties than tracheal intubation using direct laryngoscopy in this subgroup of patients . Awake fibreoptic intubation under sedation should be considered in patients with known cervical spine subluxation, which allows for assessment of neurological symptoms indicating spinal compression. Expertise is required for this technique, and it is unlikely to be appropriate under emergency conditions, or if excessive blood or secretions are in the airway.
A surgical tracheostomy under local anaesthesia may be indicated in emergency situations and in patients who have symptoms of upper airway obstruction.
Intra-operatively, patients with RA present problems with positioning due to joint deformities and fragile skin due to steroid therapy. Pressure points should be meticulously padded, the neck adequately supported and skin handled with care. Excessive manipulation of stiff and fixed joints should be avoided.
It is worth noting that the prolonged, relative spinal malposition inherent in the use of general anaesthesia, in a patient with possible spinal stenosis, may have a profound deleterious effect. In the American Society of Anesthesiologists Closed Claims Analysis, most cervical cord injuries occurred in the absence of traumatic injury, instability and airway difficulties. Cervical spine procedures and operations performed in the sitting position were identified as being particularly high-risk .
‘Awake’ cervical positioning is a potential solution for such procedures, but it cannot be predicted whether a position will still be tolerable some hours later. Attention to the maintenance of spinal cord perfusion may be important and hypotension should be avoided. Spinal cord monitoring techniques (sensory and motor evoked potentials) may be of use in assessing cord perfusion and preventing prolonged hypotension, but they have not been shown to improve outcome .
In patients receiving general anaesthesia, special attention should be considered in patients receiving methotrexate due to the potential interaction with nitrous oxide. The potential for folate depletion has only been demonstrated experimentally, but these studies suggest nitrous oxide should be avoided [32, 33].
The use of immunosuppressive treatments put patients with RA at an increased risk of infections. Strict aseptic technique should be adopted for intravascular access and regional blocks. Appropriate antibiotic prophylaxis should be given before starting surgery.
Patients taking more than 10 mg prednisolone per day should be given appropriate peri-operative steroid cover. Patients should continue their regular prednisolone and receive hydrocortisone intra-operatively to cover the stress response to surgery. Depending on the type of procedure, hydrocortisone may need to be continued into the postoperative period .
Careful observation of the airway and breathing are required in the immediate postoperative period. Pre-existing glottic stenosis due to bilateral ankylosis of the cricoarytenoid joints (see above) may be asymptomatic pre-operatively, but with the additional oedema caused by tracheal intubation, complete airway obstruction may occur following extubation. There are multiple case reports highlighting this complication, which may arise several hours postoperatively, necessitate reintubation or in some cases a tracheostomy, and may be fatal [12, 61–63].
Appropriate thromboprophylaxis should be prescribed, as patients with RA tend to have a slower recovery and return to mobilisation. Patients with RA, in general, are considered to be in a hypercoagulable state. Such patients receiving corticosteroids showed a hypercoagulable state compared with patients suffering from osteoarthritis in the peri-operative period following total knee arthroplasty .
Patients with RA may be at higher risk of peptic ulceration, especially if they are on a combination of steroids and NSAIDs, and appropriate prophylaxis should be considered.
Standard physiotherapy and breathing exercises should be instituted as early as possible due to the increased infection risk. Importantly, if signs of a postoperative infection develop, DMARDs should be suspended temporarily.
Pain should be adequately controlled to avoid delayed mobilisation, venous thromboembolism and chest infections. Opioid analgesia can be used in carefully monitored doses to reduce the incidence of side effects. Patients may find it difficult or impossible to use a PCA due to joint deformity and muscle weakness. In these cases, nurse-controlled analgesia or modified devices are possible alternatives.