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28. INTERVENTIONAL CHRONIC pain, nonradicular arm pain, groin pain, noncardiac spinal and myofascial pain); and anticonvulsants TREATMENT IN MATURE THEATERS , and . The most common diag- and tricyclic antidepressants (usually prescribed for OF OPERATION noses conferred on these patients were lumbosacral radicular and other forms of ). The , recurrence of postsurgical pain, large majority of patients received at least one inter- IMPACT OF NONBATTLE-RELATED facetogenic pain, myofascial pain, neuro- ventional procedure. The most frequently employed AND TREATMENT pathic pain, and lumbar degenerative disc . blocks were lumbar transforaminal epidural The most common noninterventional treatments steroid injections (ESIs), trigger point injections, Acute nonbattle injuries (NBIs) and have been nonsteroidal antiinflammatory drugs cervical ESIs, lumbar facet blocks, various groin conditions that recur during war have been termed (NSAIDs; > 90%); physical referral (for back blocks, and plantar fascia injections. Table 28-1 lists the “hidden epidemic” by the former pain, neck pain, and leg pain); muscle relaxants (for procedures for common nerve blocks conducted in general of the US Army, James Peake. Since statistics have been kept, the impact of NBIs on unit readiness TABLE 28-1 has increased. In World War I, NBI was the fourth leading cause of soldier attrition. In World War II PROCEDURES FOR COMMON NERVE BLOCKS CONDUCTED IN THEATER and the Korean conflict, NBIs were the third leading cause of morbidity. By the Vietnam War, NBIs had Injection Injectate Need for Comments become the leading cause of admissions, Volume* (mL) ? where they have remained ever since. However, increasing evidence demonstrates that in-theater Cervical ESI 2–4 Yes Use of local anesthetic controversial. Cervical TFESI may management of NBIs and recurrent chronic pain result in death or paraplegia and should not be done in austere environment. syndromes can improve return-to-duty rates. The current system of military treatment levels, Interlaminar lumbar ESI 3–5 Strongly Performing blind ESI associated with a high likelihood of advised injectate failing to reach targeted area. designed to facilitate the rapid evacuation of wounded soldiers based on their medical condi- Transforaminal lumbar 2–3 Yes Superior outcomes compared to interlaminar ESI. tion and needs, was developed in World War ESI II—predating the establishment of Intraarticular facet blocks Cervical: 1 Yes Likelihood of relief higher in patients with acute as a . No personnel are currently Lumbar: 1–2 inflammatory process. deployed specifically for pain management (acute or Trochanteric bursa 3–5 No Similar outcomes for fluoroscopically and landmark- chronic) at level-III combat support hospital (CSH) injection guided injections. facilities in either Iraq or Afghanistan. Instead, anes- Sacroiliac block 2–4 Yes < 25% chance of intraarticular spread in landmark-guided thesiologists and other pain specialists are deployed injections. in their primary specialties and are expected to Lateral epicondylar 0.5–1.5 No Mixed results for treatment. provide pain management services as needed in ad- injection dition to their regular full-time duties. This situation Subacromial bursa 4–10 Advised May use posterior or anterolateral approach; 50%–80% has resulted in a varying standard of pain manage- injection accuracy rate for blinded injections. ment care in theaters of operation. The modern CSH has key infrastructure such as services (eg, Piriformis muscle 3–8 Yes May use nerve stimulator to locate (adjacent injection to muscle) if fluoroscopy is not available. Injection of local fluoroscopy, , computed tomography) anesthetic may cause sciatic nerve . and full surgical, laboratory, and support, which can facilitate chronic pain clinical services if Carpal tunnel injection 1–2 No Not superior to NSAID treatment after 2 months. properly staffed. Greater occipital nerve 2–4 No Difficult to clinically distinguish from referred cervical The most common presenting complaints of NBI injection pain. during Operation Iraqi Freedom have been radicular ESI: epidural steroid injection. NSAID: nonsteroidal antiinflammatory drug. TFESI: transforaminal epidural steroid injection. leg pain, axial low (LBP), nonradicular leg *Volume of injectate consists of 1 to 2 mL of depot (long-acting) corticosteroid plus local anesthetic. 107 28 INTERVENTIONAL CHRONIC PAIN TREATMENT IN MATURE THEATERS OF OPERATION

theater. Significantly, when treated in theater, 94.7% A mainstay interventional treatment for LBP Zygapophyseal Joint Pain. Lumbar zygapophyseal of soldiers returned to their units. Differences in is ESI. ESIs exert their beneficial effects through (facet) joint pain accounts for approximately 15% of return-to-duty rates support aggressive pain man- their antiinflammatory properties, inhibition of patients with chronic axial LBP. Typical presentation is agement in forward-deployed areas. the enzyme phospholipase A2, and suppression of a dull aching pain, usually bilateral, that radiates from ectopic discharges from injured neurons. Although the low back into the buttocks and thigh. Although TRIAGING PATIENTS FOR TREATMENT ESIs have been successfully used to treat axial back the history and can be sugges- As a result of limited pain management pain, ideal candidates for the procedure are those tive of facet joint pain, an analgesic response to fluo- resources, coupled with the risk involved with with pain of less than 6 months’ duration, leg pain roscopically guided low-volume diagnostic blocks, soldier transport, healthcare providers must triage greater than back pain, young age, intermittent of either the zygapophyseal themselves or the NBI pain patients based on the anticipated risk– pain, and absence of concomitant . medial branches that innervate them, is the gold stan- benefit ratio. Soldiers with acute or recurrent The use of fluoroscopic guidance is highly recom- dard for diagnosis. The interventional treatment of overuse injuries (eg, tendonitis or ) can mended for interlaminar ESIs and is required for facetogenic pain consists of either intraarticular injec- usually be handled at a level I facility such as a transforaminal ESIs. ESIs performed without the tions with corticosteroid, which may benefit a small battalion aid station. For soldiers who require more fluoroscope have a high technical failure rate, even percentage of patients with an acute inflammatory sophisticated interventions, the battalion or brigade when performed by experienced practitioners. component, or more frequently radiofrequency dener- surgeon must decide whether a medical evacuation Transforaminal ESIs, although technically more vation of the that innervate the painful joints. to a CSH is warranted. This decision is based upon challenging than interlaminar ESIs, are generally Because of the lack of radiofrequency capability, com- several factors: the likelihood of quick resolution of associated with superior outcomes because medica- bination diagnostic/therapeutic intraarticular facet the pain issue, the soldier’s motivation to remain in tion is deposited directly over the affected nerve injections are recommended in theater. In patients theater, the soldier’s military occupational specialty, root (Figure 28-1). with radiological evidence of an acute inflammatory the probability of recurrence, the commander’s Patients suspected of radicular pain should process, intraarticular corticosteroids may afford up to desire to keep the soldier in theater, the treatment receive computed tomography (CT) scans of the 3 months of excellent pain relief (Figure 28-2). capabilities at the CSH, and the risk of medical appropriate spine evacuation. level. Whereas magnetic resonance Figure 28-1. Lateral fluoroscopic view demonstrat- Figure 28-2. Antero-posterior fluoroscopic view CHRONIC PAIN CONDITIONS ENCOUNTERED imagery (MRI) is the ing needle position for L4-5 transforaminal epidural demonstrating needle position for bilateral L3 and steroid injection. L4 facet joint (medial branch) nerve blocks. IN THE FIELD gold standard for imaging soft . LBP is the most common complaint and disc , CT likely to be encountered by the pain practitioner scans are sensitive deployed to the CSH. Its high incidence is probably at determining caused by a combination of factors encountered the presence of in theater: the heavy loads service members must disc . carry, frequent transportation over rough terrain in Although ESIs are military vehicles with stiff suspensions, heavy indi- considered by many vidual body armor, , and the high practitioners to be the degree of psychosocial stressors faced by soldiers best interventional deployed to combat zones. Among the various therapy for radicular causes of LBP, radiculopathy from ir- pain, controversy ritation may be the most commonly encountered exists regarding their condition. long-term efficacy.

108 INTERVENTIONAL CHRONIC PAIN TREATMENT IN MATURE THEATERS OF OPERATION 28

Sacroiliac Joint Pain. Sacroiliac (SI) joint pain is a 28 frequent source of axial LBP, accounting for roughly 15%to 20% of cases. Compared to other causes of back pain, SI joint pain is more likely to result from a specific inciting event such as a fall, motor vehicle accident, or airplane jump. The primary pain generator in younger patients with documented SI joint pain tends to be extraarticular (ie, surrounding ligaments or muscles). The typical presentation of SI joint pain is a unilateral aching pain in the low back or buttock. SI joint pain, typically associated with tenderness overlying the affected joint, is often reproducible. In patients with SI joint pain, multiple studies have demonstrated good intermediate- to long-term pain relief with intraarticular or periartic- Figures 28-4 and 28-5. Antero-posterior and lateral fluoroscopic views demonstrating right-sided C4 and C5 ular injections of corticosteroid with local anesthet- facet joint (medial branch) nerve blocks. ic. Previous studies have demonstrated that radio- graphic guidance is necessary to achieve accurate placement in or around the joint (Figure 28-3). Myofascial Pain. Myofascial pain accounts for a Cervical Spine Pain. An estimated 16% to 22% of significant percentage of axial LBP cases, with an adults suffer from chronic neck pain, with a higher estimated prevalence of around 20%.26 Frequently, prevalence seen in women. Among patients with muscle spasm is superimposed on a more acute, chronic neck pain, approximately 30% report a underlying condition. The hallmark of treatment of history of neck , most commonly the result of myofascial pain is to identify and a motor vehicle accident . In military pain , treat the underlying cause, and pharmacotherapy neck pain and cervicogenic account for Figure 28-3. Antero-posterior fluoroscopic view about 10% to 15% of NBIs. demonstrating a right side sacroiliac . with muscle relaxants and NSAIDs. When discrete bands of contracted muscle are palpable, trigger Numerous predisposing factors for neck pain point injections can provide excellent relief. are prevalent in soldiers, including prolonged static loads (from body armor), abnormal postures Spinal Stenosis and Degenerative Disc Disease. (secondary to body armor or in snipers), work- Spinal stenosis and degenerative disc disease related stress, and full-force exertion. In patients are other common causes of LBP, with a higher with acute neck or upper thoracic pain, the etiology incidence among the elderly. Whereas ESIs can is likely to be myofascial in origin. In chronic axial sometimes provide pain relief for these con- neck pain or injury, the facet joints are the ditions, the benefit is often incomplete and most common source of pain. Myofascial pain can transient. Less frequent sources of back and leg be treated with muscle relaxants, NSAIDs, tricyclic pain that need to be ruled out include osteomy- antidepressants, short-term duty modification, and elitis, vertebral fractures, and acute or worsening trigger point injections. For cervical facetogenic . pain, intraarticular steroids can provide intermedi- ate-term relief in patients with an acute inflamma- tory process (Figures 28-4 and 28-5).

109 28 INTERVENTIONAL CHRONIC PAIN TREATMENT IN MATURE THEATERS OF OPERATION

Cervical radiculopathy typically manifests provocation by various movements. Sometimes as neck pain radiating down one or both arms called “pseudosciatica,” TB can radiate into the in a dermatomal distribution, sometimes ac- distal thigh but rarely extends below the knee. companied by weakness and sensory changes. Risk factors for TB include coexisting lumbar Similar to lumbar radicular pain, cervical ra- spine pathology, gait and postural abnormalities, diculopathy can be treated with cervical ESIs leg length discrepancy, female gender, and (Figures 28-6 and 28-7). Because of reports of advanced age. It is important to note that a death and , cervical transforaminal ESIs majority of patients clinically diagnosed with TB are not recommended in an austere environment. have no MRI evidence of bursa . In Possible causes of cervicogenic headaches that these patients, the true pain generator is often may be amenable to injection therapy include tendonitis, muscle tears, or trigger points (Figure atlantooccipital and atlantoaxial joint pain. 28-9). Occipital , a frequent cause of occipital Plantar has a lifetime prevalence of headaches, is best diagnosed and treated with in- almost 10% in the general population but tends Figure 28-8. Needle position demonstrating bilateral to be more common in soldiers. Risk factors jections containing local anesthetic and corticos- greater occipital nerve blocks. teroid (Figure 28-8). include excessive walking or running, espe- cially in the early morning, on uneven surfaces, Nonradicular Leg Pain. Nonradicular leg pain or wearing heavy backpacks; having (eg, , plantar fascitis, and sociated with overuse of the affected body part. or high arches; being ; and being greater trochanteric bursitis [TB]) accounts for Piriformis syndrome tends to present as unilat- middle age or older. Conservative treatment approximately 10% of pain visits from eral buttock pain and, depending on the extent includes rest, night splints or , stretching NBIs. Many of these conditions tend to be as- of sciatic nerve involvement, pain extending into the lower leg. The diagnosis of piri- Figure 28-9. Antero-posterior fluoroscopic view demonstrating tro- chanteric bursa injection. formis syndrome Figures 28-6 and 28-7. Antero-posterior and lateral fluoroscopic views demonstrating a C5-6 epidural steroid injection. is predicated on a positive response to fluoroscopically guided intramus- cular injection. In addition to their di- agnostic utility, these injections can also be therapeutic. TB is a clinical diagnosis characterized by the association of lateral hip pain, tenderness to palpation, and pain 110 INTERVENTIONAL CHRONIC PAIN TREATMENT IN MATURE THEATERS OF OPERATION 28 exercises, and NSAIDs. Corticosteroid injections Lastly, male groin pain, , and SUMMARY may also relieve symptoms. female pelvic pain are the least likely pain condi- tions to improve with the interventional therapy In modern combat, the most common cause of Less Common Pain Complaints. Nonradicular arm available in theater. Common to all three of these soldier attrition is not battle-related injuries, but pain is less frequently encountered than nonradicu- conditions is the diagnostic dilemma each poses, the rather acute and recurrent NBIs similar to those en- lar leg pain. Aside from complex regional pain lack of any reliable pharmacologic or interventional countered in civilian pain clinics. Although recent syndrome, which is rarely encountered in soldiers treatments, and the high prevalence of coexisting evidence indicates that higher return-to-unit rates at level III facilities, other causes of nonradicular psychopathology. When a surgical is present, can be obtained with forward-deployed interven- arm pain include medial and lateral epicondylitis scar injections with corticosteroid and local anes- tional pain management capabilities, these tech- (“”), tendonitis, bursitis, and carpal thetic may afford pain relief by virtue of releasing niques are not always practical early in warfare. tunnel syndrome. Injection of any of these overuse entrapped nerves or suppressing ectopic discharges Chronic pain management in the operational setting inflammatory conditions with corticosteroid and from injured neurons. Even in soldiers who will is fraught with a unique and often dynamic set of local anesthetic may result in significant pain relief require medical evacuation, short-term relief can challenges, but the procedures can provide consid- and functional improvement. Since these injections often be obtained with nerve blocks. Most of these erable benefit in a mature theater of war with de- are targeted by palpation and landmarks, they can blocks tend to be landmark-guided, so fluoroscopy ployment of personnel and equipment as described usually be done in the field. is generally not necessary (see Table 28-1). in this chapter.

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