SPINAL INJECTIONS SECTION 5 SPINAL INJECTION GUIDELINES 219

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1 SECTION 5 SPINAL INJECTIONS SPINAL INJECTION GUIDELINES 219 Overview 219 Safety 219 Accuracy 220 Efficacy 220 Indications for spinal injection 221 Summary 222 EXAMINATION OF THE SPINE 223 CAUDAL EPIDURAL 224 Acute or chronic low back pain or sciatica 224 LUMBAR FACET JOINT 226 Chronic capsulitis 226 LUMBAR NERVE ROOT 228 Nerve root inflammation 228 SACROCOCCYGEAL JOINT 230 Coccydynia strain of coccygeal ligaments, subluxation 230 SACROILIAC JOINT 232 Acute or chronic sprain or capsulitis 232

2 CERVICAL FACET JOINT 234 Acute or chronic capsulitis 234 SUMMARY OF SUGGESTED SPINAL DOSAGES 236 REFERENCES 236

3 SPINAL INJECTION GUIDELINES 219 SPINAL INJECTION GUIDELINES We strongly recommend that clinicians wishing to give spinal injections attend recognized training courses and undergo a period of supervised practice with an experienced colleague before attempting them on their own. OVERVIEW Low back pain without disc herniation is the most common problem among chronic pain disorders, but a patho-anatomical cause can be established in only 15 % of all cases. 1 Treatments to relieve this affliction have been many, among them spinal injections engendering much controversy in the literature; opinions about efficacy, safety and relevance have differed greatly since their inception in the 1920s, with many studies considered poor quality Although epidural injections are one of the most commonly used invasive interventions in the treatment of low back pain, with or without radicular pain, there is currently little consensus about this technique and wide variation in practice. 21 There is also no agreement on the most effective approach for lumbar epidural injection, whether to use steroid, local anaesthetic, saline or a combination, or the exact volume required. Depot steroids are not licensed for spinal use 18,19 but orthopaedic and pain specialists, rheumatologists and others use these injections extensively. 20 The caudal route of administration may require a larger volume but is least likely to cause dural puncture. 22,23 A paucity of well designed, randomized controlled studies, and a lack of statistically significant results in the existing literature mean that a solid foundation for the effectiveness of spinal injection therapy is lacking. 9 NICE, the UK National Institute for Health and Clinical Excellence, recommended that patients with persistent non-specific low back pain should not be offered injections of therapeutic substances, 24 but what impact this has had on clinical practice is uncertain. A Cochrane Review found minor side-effects such as headache, dizziness, transient local pain, tingling, numbness and nausea reported in a small number of patients in only half the trials reviewed. The review concluded that there is no strong evidence for or against the use of any type of injection therapy for individuals with subacute or chronic low-back pain. 10 ã 2012, Elsevier Ltd. SAFETY All the contraindications listed in Section 2 apply, but particularly: l anticoagulant therapy with warfarin is an absolute contraindication. The incidence of intravascular uptake during lumbar spinal injection procedures is approximately 8.5%; it is greater in patients over 50, and if the caudal route is used rises to 11%. Absence of flashback of blood on pre-injection aspiration does not predict extravascular needle placement. 31 Epidural steroid injection is safe in patients receiving aspirin-like antiplatelet medications, with no excess risk of SECTION 5

4 220 SPINAL INJECTIONS serious haemorrhagic complications, i.e. spinal haematoma. Increased age, large needle gauge, needle approach, insertion at multiple interspaces, number of needle passes, large volume of injectant and accidental dural puncture are all relative risk factors for minor haemorrhagic complications. 32 Safety precautions and strict aseptic techniques are the same as for all injections. An additional hazard is the rare possibility of an intrathecal injection of local anaesthetic which may be avoided by using corticosteroid alone. The rationale is that the benefit of the brief relief of pain and the diagnostic information obtained from using an anaesthetic does not outweigh the potential risks. Normal saline can be added or Adcortyl used instead of Kenalog if additional volume is required. New neurological symptoms or worsening of pre-existing complaints that persist for more than 24 hours (median duration of symptoms 3 days, range 1 20 days) might occur after epidural injection, 32 but in the authors experience this is rare. The British Society for Rheumatology and the Royal College of Anaesthetists produce guidelines for the use of epidural injections. We commend them to all practitioners who give these injections. They can be found at: l l ACCURACY Performing spinal injections under imaging can ensure correct placement but requires specialized training and is expensive to perform, especially if done in theatre; many doctors perform these techniques blind and obtain satisfactory results. Accuracy of blind caudal epidural injections compared with targeted placement has been assessed in a few studies. In one, successful placement on the first attempt occurred in three out of four subjects. Results were improved when anatomical landmarks were identified easily (88%) and no air was palpable subcutaneously over the sacrum when injected through the needle (83%). The combination of these two signs predicted a successful injection in 91% of attempts. In another study blind injections were correctly placed in only two out of three attempts, even when the operator was confident of accurate placement. When the operator was less certain, the success rate was less than half and if the patient was obese the success rate reduced even further. In a third prospective randomized, double-blind trial, the results showed no advantage of spinal endoscopic placement compared with the more traditional caudal approach ,34,39 EFFICACY Lumber epidurals: a systematic review of epidural corticosteroids for back pain found at least 75% pain relief in the short term (1 60 days) with the number needed to treat (NNT) of 7 (7 16) and at least 50% pain relief in the long term (3 12 months) with NNT of 13 (7 314). 3 A randomized, double-blind, controlled trial concluded that lumbar interlaminar epidural

5 SPINAL INJECTION GUIDELINES 221 of local anaesthetic with steroid was effective in 86% of patients, and without steroid in 74%. 31 A systematic review indicated positive evidence (Level II-2) for short-term relief of pain from disc herniation or radiculitis utilizing blind interlaminar epidural steroid injections; there was less strong evidence for long-term pain relief for these conditions and for the short- and long-term relief of pain from spinal stenosis and from discogenic pain without radiculitis or disc herniation. 25 Another review of both caudal and lumbar epidurals also concluded that the best studies showed inconsistent results and benefits were of short duration only. 6 Yet another showed strong evidence for epidurals in the management of nerve root pain due to disc prolapse, but limited evidence in spinal stenosis. 22 A multicentre randomized controlled trial of epidurals for sciatica reported significant relief at 3 weeks but no long-term benefit. 14 In the past, large volumes have been injected into the epidural space; 33 however, a total injection volume of 8 ml is sufficient for a caudal epidural injection to reach the L4/5 level. 34 Selective guided nerve-root injections of corticosteroids are significantly more effective than those of bupivacaine alone in obviating the need for operative decompression for months following the injections in operative candidates. This finding suggests that patients who have lumbar radicular pain at one or two levels should be considered for treatment with selective nerve-root injections of corticosteroids prior to operative intervention. A significantly greater proportion of patients treated with transforaminal injection of steroid achieve relief of pain compared with those treated by transforaminal injection of local anesthetic or saline or intramuscular steroids. 30 When symptoms have been present for more than 12 months, local anaesthetic alone may be just as effective as steroid and local anaesthetic together. When conservative measures fail, nerve-root injections are effective in reducing radicular pain in patients with osteoporotic vertebral fractures and no evidence of nerve root palsy. These patients may be considered for this treatment before percutaneous vertebroplasty or operative intervention is attempted. 35,36,38 Injection of the sacroiliac joints for painful sacroiliitis appears to be safe and effective. It can be considered in patients with contraindications or complications with NSAIDs, or if other medical treatment is ineffective, 37 though often manipulative techniques can obviate the need for an injection. However, accurate placement of the drug without the use of fluoroscopy is estimated to be successful in only 12 % of patients. 40 INDICATIONS FOR SPINAL INJECTION The techniques described here include caudal epidural, nerve root, facet joint, sacroiliac joint and sacrococcygeal joint injections and the far less common technique for cervical nerve root pain. The choice between giving a caudal ornerverootinjectioncanbeaidedbythesiteofpain;ifthisisclearly unilateral in the lumbar area, or radiating down one leg, a nerve root injection may be effective. If the pain is bilateral or central in the lumbar spine, a caudal epidural may be a better choice; however, this guide is not an absolute. SECTION 5

6 222 SPINAL INJECTIONS The following are the main indications for caudal and nerve root injections: l Acute back and/or leg pain where pain makes manipulation impossible to perform l Chronic back and/or leg pain where conservative treatment has failed l Prior to considering surgery. Older patients with chronic back pain and stiffness increased on active extension may benefit from facet joint injections. A retrospective study of patients with spinal stenosis found that 35 % of patients had at least 50 % improvement; those with spondylolisthesis, single level stenosis and older than 73 had better outcomes. 28 Less commonly, injections for coccydinia or sacroiliac joint pain can be attempted in cases of acute traumatic or post-natal pain. SUMMARY There is a wide variation of opinion about the efficacy of spinal injections for back pain; adverse effects are generally minor and it cannot be ruled out that specific subgroups of patients may respond to a specific type of injection therapy. A cost-effective intervention which may be performed safely as an outpatient procedure and rapidly relieve pain, even in the short term, is worth considering for carefully selected patients with both acute and chronic low back pain provided that, as with all injection techniques, resuscitation facilities are available and the guidelines on aseptic technique are strictly followed.

7 EXAMINATION OF THE SPINE 223 EXAMINATION OF THE SPINE The capsular pattern is a set pattern of loss of motion for each joint. It indicates that there is some degree of joint capsulitis caused by degeneration, inflammation or trauma. There may be a hard end feel in advanced capsulitis. Cervical spine tests Active: flexion rotations side flexions extension Passive: rotations side flexions extension Resisted: shoulder abduction C5 shoulder lateral rotation C5 shoulder medial rotation C6 elbow flexion C6 elbow extension C7 shoulder adduction C7 wrist extension C6 wrist flexion C7 thumb extension C8 finger adduction T1 Reflexes: brachioradialis C5, biceps C6, triceps C7 Cervical capsular pattern: equal loss of rotations and side flexions, more loss of extension than flexion Lumbar spine tests Active: extension side flexions flexion Passive: hip flexion hip rotations Resisted: Resisted: foot plantarflexion S1 hip flexion L2 foot dorsiflexion L4 big toe extension L4/5 foot eversion L5/S1 knee extension L3 knee flexion S1 glutei S1 straight leg raise Reflexes: knee L3, ankle L5, S1/2 Lumbar capsular pattern: equal loss of side flexions, more loss of extension than flexion SECTION 5

8 224 SPINAL INJECTIONS CAUDAL EPIDURAL Acute or chronic low back pain or sciatica Causes and findings l Disc lesion, acute nerve entrapment l Central or bilateral pain in low back with or without sciatica or root signs l Painful: flexion and usually side flexion away from pain with nerve root tension signs Equipment Syringe Needle Adcortyl Lidocaine Total volume 5 ml Green 21G 40 mg Nil 4 ml 1.5 (40 mm) Anatomy Technique Comments Alternative approach Aftercare The spinal cord ends at the level of L1 and the thecal sac ends at S2 in most individuals. The aim of this injection is to pass a disinflaming solution through the sacral hiatus and up the canal so that it bathes the posterior aspect of the intervertebral disc, anterior aspect of the dura mater and any affected nerve roots centrally. The sacral cornua are two prominences that can be palpated at the apex of an equilateral triangle drawn from the posterior superior spines on the ileum to the coccyx. There is a thick ligament at the entrance to the canal. The angle of the curve of the canal varies widely and the placement of the needle reflects this. l Patient lies prone over small pillow l Identify sacral cornua at base of imaginary triangle with thumb l Insert needle between cornua and pass horizontally through ligament l Pass needle a short distance up canal adjusting angle to curve of sacrum l Aspirate to ensure needle has not penetrated thecal sac or blood vessel l Slowly inject solution into epidural space l Keep hand on sacrum to palpate for swelling caused by suprasacral injection Occasionally the canal is difficult to enter. This might be because of a bifid or very small canal or because the angle of the sacrum is very concave. If this is encountered, a small amount of local anaesthetic can be injected into the ligament to make penetration more comfortable and reangulation of the needle might be necessary. If clear fluid or blood is aspirated at any point the procedure is abandoned and attempted a few days later. If the affected level is higher than the common L5/S1 level or the patient is large, more volume may be required to reach these levels. In this case we recommend the addition of up to 10 ml of normal saline, depending on the level of the lesion and the size of the patient. 39 The patient is advised to keep active within pain limits and is reassessed about 10 days later. If the injection has only partially helped it can be repeated as long as improvement continues. The causes of the back pain should then be addressed weight, posture, work positions, lifting techniques, exercise, abdominal control, etc.

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10 226 SPINAL INJECTIONS LUMBAR FACET JOINT Chronic capsulitis Causes and findings l Osteoarthritis, traumatic capsulitis, ankylosing spondylitis, spondylolysis l Uni- or bilateral low back pain, sometimes with dull vague aching down leg/s l Painful: capsular pattern limitation, in spondylolysthesis combined extension with side flexion to the painful side may be the most painful movement. Equipment Syringe Needle Kenalog Lidocaine Total volume 1 ml Spinal 22G 40 mg Nil 1 ml 3 5 (90 mm) Anatomy Technique Comments Alternative approach Aftercare The lower lumbar facet or zygaphophyseal joints lie lateral to the spinous processes approximately one finger width at L3, one and a half at L4 and two fingers width at L5. They cannot be palpated but are located by marking a vertical line along the centre of the spinous processes and horizontal lines across between each process. The posterior capsule of the joint is found by inserting the needle the correct distance for that level laterally on the horizontal line. l Patient lies prone on small pillow to aid localization of spinous interspace l Identify and mark one or more tender levels l Insert needle at first selected level vertically l Angle needle slightly cephalad and medially and pass slowly down to bone l Aspirate to ensure needle point is not intrathecal or in blood vessel l Deposit solution into and around capsule l Withdraw needle and repeat at different levels if necessary Sometimes it is impossible to enter the joint, but controlled studies have shown that depositing the solution into the capsule can be therapeutically effective 11. These injections are often performed under imaging but this is less cost effective. Patient avoids excessive movement while maintaining activity. Abdominal strengthening and mobilizing exercises should be performed regularly. Occasional mobilization and hamstring stretching will help to maintain flexibility. A lumbar support may be used during activities.

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12 228 SPINAL INJECTIONS LUMBAR NERVE ROOT Nerve root inflammation Causes and findings l Spinal stenosis, nerve-root entrapment l Acute or chronic sciatica with or without root signs l Painful: flexion and usually side flexion away from pain plus nerve root tension signs Equipment Syringe Needle Kenalog Lidocaine Total volume 1 ml Spinal 22G 40 mg Nil 1 ml 3.5 (90 mm) Anatomy Technique Comments Aftercare The lumbar nerve roots emerge obliquely from the vertebral canals between the transverse processes at the level of the spinous process. Draw a vertical line along the centre of the spinous processes and horizontal lines at each spinous level. A thumb s width laterally along the horizontal line marks entry site for the needle. l Patient lies prone over small pillow to aid localization of spinous processes l Identify spinous process at painful level and mark spot along horizontal line l Insert needle and pass perpendicularly to depth of about 3 (7 cm) l Aspirate to ensure needle point is not intrathecal l Inject solution as a bolus around nerve root This injection can be especially effective when the patient is in severe pain and conservative manual therapy techniques are impossible to administer. It can also be given when caudal epidural has proved unsuccessful the caudal is technically an easier procedure but the solution might not reach the affected part of the nerve root. The needle must be repositioned if it encounters bone at a distance of about 2 (5 cm) as this means it is touching the lamina or facet joint. Equally, repositioning is necessary if the patient complains of sharp electric shock sensation because the needle will be in the nerve root. If clear fluid is aspirated the needle is intrathecal and the procedure must be abandoned, although it can be attempted a few days later. Two levels can be infiltrated at a time. A large patient may require a longer needle. If the first level injected does not relieve the symptoms, a level above or below can be tried. This is well worth trying before considering surgery. Patient keeps mobile within pain limits and is reassessed 10 days later. Repeat as necessary.