Interventional Pain Management



Interventional Pain Management


Joseph Walker

Miguel Ernesto Velez

Moorice Caparó



Introduction

Interventional pain treatment options are an important component in the multimodal approach for pain management. Interventional pain options treat the symptom of pain, potentially allowing the individual to participate in other available treatment options such as physical therapy and cognitive behavioral therapy. This reduction in pain level can improve functional outcomes. Many interventional treatments are available for the patient, and the indications for them vary as well. Selecting the correct interventional procedure, whether for spinal pain, neuropathic pain, orthopedic pain, head/neck pain, or malignant pain, can help the progression of a patient’s healing. The goal of this chapter is to give an organized overview of the various interventional pain treatment modalities that are available for a patient’s plan of care.



Spinal Pain Interventions

Spinal pain encompasses diagnoses that involve the structural components of the cervical, thoracic, lumbar, or sacrum. The potential treatment targets within the spinal column include the spinal nerve roots, the spinal articular structures, and even the spinal cord itself.



Epidural Steroid Injections


Introduction

Epidural steroid injections have been a mainstay of both subacute and chronic back pain management for many years. The procedure is used to treat radicular pain originating from the cervical, thoracic, or lumbar regions of
the spine. There are many underlying causes of radicular pain. The most common include: (1) nerve root compression from disk herniation, (2) spondylosis, (3) spinal stenosis, or (4) postlaminectomy pain syndrome (Boswell et al., 2007).

Epidural steroid injections can help maintain conservative treatment, predict surgical outcome, reduce opioid use, and improve return to work.


Clinical Features

Although a patient’s presentation may vary, radicular symptoms are generally described as sharp, burning, or shooting sensation that radiates down an extremity. This radiating referral pattern typically follows a specific dermatomal distribution. Paresthesia may also be reported. Patient may also complain of motor weakness when performing certain functions such as dorsiflexion (L4-L5), hip flexion (L2-L4), and plantar flexion (S1). Patients with spinal stenosis will have complaints because of symptoms of neurogenic claudication. This includes (1) pain that is worse after standing and walking followed by pain relief soon after sitting down and (2) pain while going downstairs compared to going up as stenosis and pain are reduced with spine flexion (Friedrich & Harrast, 2010). For all patients presenting with radicular pain, a history of bowel and bladder function must be obtained as impaired function may point toward spinal cord compression needing neurosurgical consultation. Severe and/or rapidly progressing neurologic symptoms should also warrant further workup and possible neurosurgical evaluation (Allegri et al., 2016).


Physical examination findings

Careful physical examination of the myotome (motor strength), dermatome (sensation), and deep tendon reflexes of the various spinal segments must be performed in order to help clinically localize the spinal level of involvement. Examples of lumbar myotomal weakness include: weakness with plantar flexor or hip extension for an S1 root involvement, weakness with foot eversion or hip abduction for L5 root involvement, or weakness with ankle dorsiflexion or knee extension for L4 root involvement. Within a specific dermatomal distribution, the patient may exhibit loss of sensation to light touch, allodynia with the pinch-roll test, or hyperalgesia with pinprick test. Neural tension maneuvers on physical examination, such as the Spurling’s maneuver for the cervical spine and supine straight leg raise for the lumbar spine, may help localize nerve root impingement because of disk herniation. These physical examination tests also screen for spinal cord involvement in red flag situations such as myelopathy or central cord syndrome. Signs of spinal cord involvement include frank hyperreflexia, clonus, or absent/pathologic reflexes (Hoffman or Babinski signs) (Allegri et al., 2016).


Interventional procedure type




Brief description of procedure

The procedure consists of placing steroid medication to the epidural space. The epidural space is located between the dura and the spinal canal. The dura is the outermost covering of spinal cord. Both the epidural injection procedure approach and the selected spinal level to inject are individualized. These two variables depend on (1) patient presentation, (2) findings on imaging, (3) practice preference, (4) prior surgery, and (5) previous response to other epidural injections (Patel, Wasserman, & Imani, 2015).



  • Transforaminal Approach (Figure 9-1)—The target for this approach is the space between each vertebra where the nerve exits the spinal canal, called the neural foramina. The neural foramina are located more laterally. This approach places the medication more anteriorly in the epidural space and closely targets the specific nerve root that exits at that level on that side.


  • Interlaminar Approach (Figures 9-2 and 9-3)—The target for this approach is the space between the lamina of subsequent vertebrae. The space is located posteriorly just slightly off midline. This approach places the medication more in the posterior aspect of the epidural space.


  • Caudal Approach (Figure 9-4)—The target for this approach is the sacral hiatus that is located at the distal part of the sacrum and may access the epidural space. This approach places the medication in the caudal aspect of the spinal column, targeting more of the lower lumbar and sacral roots. This technique can be useful in the postsurgical spine as the transforaminal and interlaminar space may be altered.






Figure 9-1. Transforaminal approach for epidural steroid injection.







Figure 9-2. Interlaminar approach for epidural steroid injection of the lumbar spine.






Figure 9-3. Interlaminar approach for epidural steroid injection of the cervical spine.







Figure 9-4. Caudal approach for epidural steroid injection.



Risk/potential adverse effects

Direct injection into the nerve root or even spinal cord can result in acute spinal cord injury. Needle puncture and injection into the intervertebral disk may predispose to diskitis (Patel, Wasserman, & Imani, 2015). Epidural hematomas may result from injury to the vascular bundle as it enters the neural foramina. Dural tears, vasovagal syncope, and systemic corticosteroid side effects have also been seen in practice (Friedrich & Harrast, 2010).


Imaging modalities used to perform procedure

Epidural steroid injections were originally done without any image guidance. This lack of visual confirmation resulted in inaccurate needle placement in up to 30% of cases. This was even in the hands of experienced clinicians (Patel, Wasserman, & Imani, 2015).


Fluoroscopy is by far more common as it involves less radiation overall. Ultrasound guidance has been used for needle placement as well.



Type of medications used

A combination of steroid and local anesthetic is used within the injectate. There is no consensus in the dosage or type of corticosteroid used. Radiopaque water-soluble contrast is used to confirm needle placement. Contrast material is used to assist with avoidance of intravascular injection of the steroid injectate (Patel, Wasserman, & Imani, 2015).


Sedations used

Sedation is not typically used for this procedure.


Length of time for the procedure

Five to 10 minutes.


Expected postprocedural care

Typical postprocedural restrictions/limitations include: (1) avoidance of driving, (2) avoidance of strenuous activity following procedure, and (3) avoidance of submerging the injection site in water. The patient should be closely monitored for worsening of pain, signs of infection, or systemic corticosteroid side effects. Immediate medical help should be sought if patient experiences sudden-onset weakness or loss of bowel/bladder function following procedure.


Frequency of having this procedure

There is no consensus on timing and frequency of epidural steroid injections. Some international interventional spine societies recommend no more than four injections in a 6-month period.


Gauging the patient’s response to prior injection is essential to determine if another injection is warranted (Friedrich & Harrast, 2010).


Ways of documentation of efficacy

Documentation of treatment outcome can be done via (1) the numeric rating scale and (2) the visual analog scale at different time intervals during treatment.


Zygapophyseal Joint Interventions


Introduction

The zygapophyseal, or facet, joints are a common cause of chronic back and neck pain. Over time, the zygapophyseal joints undergo osteoarthritic degenerative changes. These degenerative joint changes when combined with degenerative disk changes are collectively called spondylosis. Spondylosis accounts for 10% to 50% of all chronic lower back pain cases (Schwarzer et al., 1994).

The superior articular processes of the lower vertebrae articulate with the inferior articular processes of the vertebrae above (Gellhorn, Katz, & Suri, 2013).
Facet joints are innervated by the medial branches of the dorsal primary rami of the spinal nerves.



Clinical features

The axial pain may be unilateral or bilateral. Zygapophyseal joint-mediated pain may also radiate into the upper and lower extremities. This type of pain may present with localized referred patterns to the occiput, posterior scapular/shoulder, buttocks, or the thighs (Gellhorn, Katz, & Suri, 2013).



Physical examination findings

Specific physical examination findings for facet joint-mediated pain are worsening pain with extension, pain with extension-rotation also known as Kemp’s test, and palpatory tenderness along facet joint line.



Interventional procedure type

The injection is either intraarticular into the facet joint or onto the medial branch nerve. The rhizotomy targets the medial branch nerve.


Brief description of procedure

A radiofrequency ablation (RFA) is also known as facet joint neurotomy or rhizotomy. RFA is typically performed after the medial branch block or facet joint injection. This procedure is primarily therapeutic and can provide pain relief for as long as 6 to 12 months. While the patient is in the prone position, the skin is cleaned and draped in a sterile fashion. The target levels are determined based on anatomic landmarks under fluoroscopy.




  • ▶ For facet joint injections (Figures 9-5 and 9-6): After administering local anesthetic superficially, the spinal needle is guided intraarticularly into the zygapophyseal joint. A combination of anesthetic and steroid is then administered. The facet joint injection is a therapeutic procedure.


  • ▶ For medial branch block: After administering local anesthetic superficially, the spinal needle is guided to the location of the medial branch nerve. The medial branch nerve is found at the junction of the superior articular process and transverse process (for thoracic and lumbar) or at the lateral masses (for cervical). The zygapophyseal joint is dually innervated and as such two medial branches need to be injected for a single zygapophyseal joint. Anesthetic and/or steroid is then administered. The medial branch block is a diagnostic procedure.







    Figure 9-5. Facet joint injection of the lumbar spine.






    Figure 9-6. Facet joint injection of the cervical spine.


  • ▶ For RFA: After administering local anesthetic, a radiofrequency probe is guided to the location of the medial branch nerve (Gadsen, 2013). The medial branch nerve is found at the junction of the superior articular process and transverse process (for thoracic and lumbar) or at the lateral masses (for cervical). Sensory and motor stimulation is done to confirm that the ventral ramus
    or spinal nerves are not being ablated. Ablation is then performed with the radiofrequency generator at 80°C to 85°C for 90 seconds (Manchikanti et al., 2003). Once again, the zygapophyseal joint is dually innervated and as such the ablation is performed at a minimum of two medial branches to influence a single zygapophyseal joint. RFA is a therapeutic procedure.



Risk/potential adverse effects

As with other spinal injections, the complications are usually related to needle placement and drug administration. The complications include dural puncture, spinal cord injury, infection, intravascular injection, spinal anesthesia, chemical meningitis, neural trauma, pneumothorax, and hematoma formation. Vertebral artery injury is more common with cervical intraarticular injections (Manchikanti et al., 2003). Most problems, such as local swelling, pain at the site of the needle insertion, and pain in the low back, are typically self-limited.


Imaging modalities used to perform procedure

The procedure is most commonly performed under fluoroscopic guidance. Ultrasound has been utilized also for visualization of needle/radiofrequency probe placement. Other less commonly used imaging modalities include CT and magnetic resonance imaging (MRI) (Manchikanti et al., 2015).


Type of medications used

Facet joint injections and RFA both typically use local anesthetics such as lidocaine or bupivacaine for superficial infiltration. Facet joint injections use a steroid as the primary injectate into the joint. Medial branch blocks use either a short-acting or a long-acting local anesthetic alone for the injection of the medial branch nerve. During the RFA procedure, some providers may inject steroid at the nerve in addition to the rhizotomy, although evidence of improved pain relief is limited.


Sedations used

These procedures are usually without sedation, although this may vary depending on the patient or provider. If sedation is utilized, midazolam or fentanyl is typically used. Studies have shown that administration of sedation can be a confounding factor in the diagnosis of facet joint-mediated pain with medial branch block (Manchikanti et al., 2004, 2016).


Length of time for the procedure

Five to 30 minutes. Length of time for the procedure depends on the provider skillset and the number of levels being done.



Expected postprocedural care

Patients are typically advised to rest for the remainder of the day, to limit heavy lifting and to avoid strenuous activity. If sedation is administered, the patient is to avoid driving and operating heavy machinery for the remainder of the day after the procedure.


Frequency of having this procedure

The specific frequency of the treatments performed may vary depending on the effect of the procedure and provider preference.



Ways of documentation of efficacy

Documentation of treatment outcome can be done via (1) numeric rating scale, (2) visual analog scale, (3) functional status, and (4) health-related quality of life scale (EuroQual-5 dimensions; EQ5D) (Manchikanti et al., 2015).


Sacroiliac Joint Injections


Introduction

The sacroiliac joint is a true synovial joint between the sacrum and the ilium, and although it is a relatively immobile joint, it is involved in transferring weight from the trunk to the lower extremities (Raj & Dulebohn, 2017). Pain and dysfunction can be attributed to abnormal movement or misalignment, trauma, inflammation, and pregnancy (Forst, Wheeler, Fortin, & Vilensky, 2006).



Clinical features

The radiating pain does not usually extend below the knee. Groin pain is another referral pattern in a subset of patients (Jung et al., 2007).


Physical examination findings

The patient may point directly to the area within 1 cm of the posterior superior iliac crest (Fortin’s finger test). Pain can be reproduced by placing direct stress on the sacroiliac joint. This can be done via the sacroiliac joint distraction maneuver, sacral thigh thrusts in supine position, or with compression at the lateral hip while patient is side lying. Patrick’s test also known as FABER (Flexion, Abduction, and External Rotation) test has been reported as having highest positivity in patients with confirmed sacroiliac joint pathology (Telli et al., 2018). Other provocative tests include Gaenslen’s test in which the patient is placed at the edge of the examination table in supine position, with one hip maximally extended and the opposite hip maximally flexed.




Interventional procedure type

The injection is intraarticular into the sacroiliac joint.


Brief description of procedure

Patient is placed prone. The fluoroscopy machine is positioned over distal one third to one fifth of sacroiliac joint. The spinal needle is guided toward posterior aspect of joint (Figure 9-7). Needle depth can be confirmed with an oblique or lateral fluoroscopic view. Once the intraarticular joint space is reached, needle placement is confirmed with radiopaque contrast. Approximately 1 to 3 mL of injectate, a combination of steroid and local anesthetic, is then injected into the joint (Patel, Wasserman, & Imani, 2015).



Risk/potential adverse effects

The complications are usually related infection, spread of medication to adjacent tissue, bleeding, bruising, and pain at injection site.


Imaging modalities used to perform procedure

Sacroiliac joint injections may be done without image guidance. This, however, increases the risk of injury to surrounding tissue given the deep nature of the sacroiliac
joint (Pang, Mahajan, & Fishmann, 2005). Fluoroscopic guidance is preferred over CT guidance because of concern for increased radiation exposure and overall expense. Low-dose CT protocols may decrease radiation exposure to that of pulsed fluoroscopy (Artner, Cakir, Reichel, & Lattig, 2012). Ultrasound is also an emerging way for needle guidance.






Figure 9-7. Sacroiliac joint injection.


Type of medications used

An anesthetic such a lidocaine or bupivacaine is usually mixed with a corticosteroid for longer term effects. Viscosupplementation with hyaluronic acid may be used (Srejic, Calvillo, & Kabakibou, 1999).


Sedations used

Sedation is not used during this procedure.


Length of time for the procedure

Five to 10 minutes.


Expected postprocedural care

Patients are typically advised to avoid submerging injection site in water and to avoid strenuous activity immediately following procedure (Dussault, Kaplan, & Anderson, 2000).


Frequency of having this procedure

The number of procedures yearly varies but typically numbers about three in a 12-month period. Frequency will depend on patient’s response to treatment and physician’s preference.


Ways of documentation of efficacy

Documentation of treatment outcome can be done via (1) visual analog scale and (2) numeric pain rating scale (Scholten, Patel, Christos, & Singh, 2015).


Spinal Cord Stimulation


Introduction

Used to treat chronic and intractable pain, spinal cord stimulation (SCS) is accomplished via an implantable subcutaneous device.


Common indications for SCS include complex regional pain syndrome (CRPS) (Types I and II), failed back surgery syndrome (FBSS), peripheral vascular disease, visceral pain (such as intractable angina), and peripheral neuropathy (Mekhail et al., 2011; Latif, Nedeljkovic, & Stevenson, 2001). CRPS (Types I and II) and FBSS account for 82% of the cases where SCS is utilized.



Clinical features

The two most common indications for SCS are briefly reviewed here.




  • ▶ Complex Regional Pain Syndrome: CRPS (Types I and II) is neuropathic/sympathetically mediated pain syndrome. CRPS Type I presents without a known nerve damage, whereas Type II presents with known nerve damage. Patients typically report hyperesthesia, allodynia, temperature changes, skin color changes, decreased range of motion, decreased strength, trophic changes (such as changes in hair, nail, or skin), and edema (Freedman et al., 2014).


  • ▶ Failed back surgery syndrome: FBSS encompasses a constellation of conditions describing recurring low back pain, with or without neuropathic pain, following one or more spine surgeries. It is important to (1) assess the pain characteristics, (2) exclude other serious diagnoses, and (3) compare to the patient’s presurgical pain (Chan & Peng, 2011).


Physical examination findings



  • ▶ CRPS: Physical examination findings may include hyperalgesia to pinprick, allodynia to pinch and roll test, temperature asymmetry, sweating changes or asymmetry, decreased range of motion, weakness, tremor, dystonia, and trophic changes (Freedman et al., 2014; Maleki et al., 2000).


  • ▶ FBSS: The physical examination is similar to any comprehensive back pain examination and it should be focused and directed by the findings provided on the history (Chan & Peng, 2011).


Interventional procedure type

The SCS trial is an outpatient interventional spine procedure. The SCS permanent placement is a surgical procedure.


Brief description of procedure

Before a permanent subcutaneous device is implanted, an SCS trial lasting between 5 and 7 days is done with an external device. However, lead placement is done in a similar fashion in both cases. General anesthesia is then administered. Spinal anatomic landmarks are determined by using fluoroscopy. A needle is inserted into the epidural space. A stimulator lead is then advanced through the needle. The second lead is placed in the same fashion on the opposite side. After coverage of stimulation is confirmed, the needles are withdrawn, leaving the leads in place. If a paddle lead is used for a greater coverage area, a laminectomy may need to be done for permanent lead placement. If the lead trial is successful in terms of pain relief, functioning, and decreased analgesic medication usage, the permanent leads and device are then placed.




Risk/potential adverse effects

The complications of this procedure include poor paresthesia coverage, lead migration or breakage, failure of electrode lead, infection, bleeding, paralysis, nerve injury, and death (Manchikanti et al., 2003).


Imaging modalities used to perform procedure

Both the SCS trial and permanent placement are done under fluoroscopic guidance.


Type of medications used

Local anesthetic such as lidocaine is typically used superficially.


Sedations used

General anesthesia is typically done for lead placement.


Length of time for the procedure

The lead insertion placement may require between 30 minutes and 1 hour. The patient may require an overnight hospital stay.


Expected postprocedural care

Recovery takes between 6 and 8 weeks. Patients should refrain from strenuous physical activity, twisting, bending, or heavy lifting (Sjm.com, 2018).


Frequency of having this procedure

After an SCS trial and permanent device placement, further procedures are typically not performed unless a revision is needed.


Ways of documentation of efficacy

Documentation of treatment outcome can be done via visual analog pain scale, Oswestry Disability Index, sickness impact profile (SIP), health-related quality of life, EQ5D, functional level, activities of daily living, analgesic use, work status, and CRPS severity score (Barolat et al., 2001; Burton, 1975; Manchikanti et al., 2003).


Intrathecal Drug Delivery Systems


Introduction

Intrathecal drug delivery systems are established alternatives for the management of pain and spasticity when less invasive options are not feasible or have proven ineffective.


Medication is delivered directly into the intrathecal space via subcutaneously inserted pump and catheter system. Standard practice includes a trial of the medication injected directly into intrathecal space. If it proves effective, then the patient will undergo permanent surgical implantation of pump and reservoir system (Duarte, Raphael, & Eldabe, 2016).



Clinical features

The typical patient who presents for intrathecal drug delivery has (1) the above-mentioned diagnoses, (2) a long-standing and complex pain history, and (3) attempted multiple treatment modalities such as oral medications and invasive procedures. The physical examination performed is specific for the presenting diagnosis. Spasticity is graded using the Modified Ashworth Scale (Duarte et al., 2011).


Interventional procedure type

The trial for the efficacy of the intrathecal drug is an outpatient interventional procedure. The implantation of the intrathecal drug delivery system is a surgical procedure. The delivery system is subcutaneously implanted and the corresponding reservoir system is placed intrathecally. Both are connected to each other via a catheter.


Brief description of procedure

Device implantation usually occurs after a successful trial of medication delivered intrathecally whereupon the patient had some sustained pain relief. The procedure consists of two incisions. The first incision is for the intrathecal catheter that is placed in the thoracolumbar area posteriorly, which is anchored to the underlying fascia. The second incision is for pump and reservoir system implantation that is typically positioned in the abdominal wall but may also be positioned in other areas. Specific pump placement will vary depending on patient preference (such as sleeping position), avoidance of bony landmarks, and other anatomic limitations. Pump system is placed at a depth of 1.5 to 2.5 cm to allow for easy access for refilling procedures. Reservoir systems will need to be refilled at least every 6 months, although they are usually refilled on a 3- to 4-month basis depending upon medication dosing. During the refilling process, the pump is accessed percutaneously via the self-sealing silicone septum that is located in the center of the anterior aspect of the pump system (Bottros & Christo, 2014).




Risk/potential adverse effects

The potential adverse effects from this procedure are both general and specific. Generally, as with any other surgery, surgical site infection, bleeding, and bruising postprocedure can be encountered.


Patients need to be monitored closely for signs of withdrawal and overdose of medication being used intrathecally. Symptoms of withdrawal include sudden increase in spasticity, fever, tachycardia, hallucinations, and seizures. Other device-specific complications include: catheter kinking, catheter dislodgement, delivery device failure, programming failure, and neural axial infections (epidural abscess, meningitis). Although rare, neurologic deficits have been reported from inflammatory mass development at catheter tip and neurotoxicity of medication (Knight, Brand, Mchaourab, & Veneziano, 2007).


Imaging modalities used to perform procedure

The trial and the implantation procedure is performed under fluoroscopy guidance to confirm intrathecal positioning (Duarte, Raphael, & Eldabe, 2016).


Types of medications used

The most common medications used for continuous intrathecal delivery include: (1) opioids (such as morphine and hydromorphone), (2) local anesthetics (such as bupivacaine), (3) antispasmodic medications (such as baclofen), and others such as clonidine and ziconotide (Eldabe et al., 2015).


Sedations used

The trial is done under local anesthesia. The permanent device implantation is done under sedation. The refilling process requires local anesthesia.


Length of time for the procedure

The procedural time for the intrathecal trial of medication usually is 15 to 30 minutes. The implantation of the delivery device, reservoir, and intrathecal catheter may take 1 to 4 hours. Postimplantation surgical care will likely require an overnight stay for vital sign monitoring and medication dose titration. Refilling procedure is an outpatient procedure and typically takes 15 to 30 minutes.


Expected postprocedural care

Careful monitoring is done for any signs and symptoms of complications such as medication overdose/withdrawal, infections, and cerebrospinal fluid leak. Patients must have clearly defined pathways for dealing with complications and possible adverse effects (i.e., knowing who to call or where to go if a situation were to arise). Patients are instructed to avoid hot tubs/hot showers/saunas as well as scuba diving over 10 m as changes in pressure and temperature may affect the flow rate of the medication within the system (Eldabe et al., 2015; Knight et al., 2007).



Frequency of having this procedure

Implantation is typically a one-time permanent procedure but may be removed if any complication occurs. The refilling process typically occurs once to twice a year.


Ways of documentation of efficacy

Documentation of treatment outcome can be done via (1) visual analog pain scale, (2) patient self-reported side effects, (3) Modified Ashworth Scale, and (4) impairment of activities of daily living for spastic patients (Bottros & Christo, 2014).


Diskography


Introduction

The intervertebral disks are innervated by the sinuvertebral nerve. This nerve has nociceptive and sympathetic innervation. Irritation and disruption of this nerve can cause pain. As such, the intervertebral disk can be a source of back pain. Internal disk disruption (IDD) is thought to be the most common cause of diskogenic pain. IDD results from disk degradation and development of radial fissures from the nucleus pulposus into the annulus fibrosus (Simon, McAuliffe, Shamim, Vuong, & Tahaei, 2014).


This process entails puncture, stimulation, and assessment of the intervertebral disk. This procedure is the next step in the diagnostic algorithm if noninvasive diagnostic testing has not confirmed an etiology for a patient’s presenting pain complaint (Manchikanti et al., 2003).


Clinical features

This pain may be described as deep/dull, associated with paraspinal muscle tightness, and worsens with Valsalva-type maneuvers (Simon et al., 2014).



Physical examination findings

On physical examination, pertinent findings include limited lumbar range of motion, kinesiophobia (fear of movement), and positive neural tension tests reproducing lower extremity or buttock pain (Simon et al., 2014).



Interventional procedure type

Diskography is an outpatient interventional diagnostic procedure.


Brief description of procedure

The patient is placed prone for the procedure. Under fluoroscopic guidance, a radiopaque contrast is injected into the nucleus pulposus of the disk (Figure 9-8).







Figure 9-8. Diskography of L3-L4, L4-L5, and L5-S1.

The pressures are recorded via manometry. After the fluoroscopic diskogram procedure is completed, the patient has a spinal CT scan. This scan further elucidates the morphology of the tested intervertebral disks.



Risk/potential adverse effects

Complications for the procedure include infection (diskitis), neural trauma, intravascular penetration, and spinal cord trauma (Manchikanti et al., 2003).


Imaging modalities used to perform procedure



Type of medications used

Local anesthetic such as lidocaine may be used for superficial anesthesia. A radiopaque contrast, such as iohexol, is typically injected into the disk to obtain the information noted earlier. Frequently, an antibiotic (cephalosporin class) is injected as well to reduce the risk of postprocedural infection.



Sedations used

Typically, sedation is not used during this procedure as it may confound the diagnostic results.


Length of time for the procedure

Procedure may last between 30 minutes and 1 hour. The variance of time depends on the number of disks evaluated.


Expected postprocedural care

After the procedure, the patient is to avoid overly strenuous activity. The patient may have a few days of postprocedural soreness. After the procedure, it is important to monitor for signs of infection such as fevers or chills.


Frequency of having this procedure

The goal of the test is to determine if the intervertebral disk is the main etiology of a patient’s pain compliant. During the course of the clinical workup, this procedure is typically performed once.



Ways of documentation of efficacy

Documentation of treatment outcome can be done via (1) numeric rating scale, (2) modified Dallas Discogram Criteria, (3) American Medical Association (AMA) functional impairment guidelines, and (4) Oswestry Disability Index.


Neuropathic Pain Interventions

Neuropathic pain is pain resulting from damage to the peripheral nerves or to the central nervous system itself. More than 1.5 billion people worldwide suffer from chronic pain; approximately 3% to 4.5% of the global population suffers from neuropathic pain, with incidence rate increasing with age. Various interventional procedures are available for the treatment of this category of pain.


Neuropathic Pain: Peripheral Interventions


Peripheral Nerve Blocks


Introduction

Peripheral nerve blocks are utilized in acute situations, in surgical care, and to assist the management of persistent and chronic pain. The goal of these injections is to extinguish to nociceptive originating from a site of injury and to extinguish maladaptive neuropathic input from the nerves themselves (Garmon & O’Rourke, 2018).


Common targets of the upper quarter in chronic pain management include: median nerve, ulnar nerve, radial
nerve, suprascapular nerve, and the intercostal nerves. Common targets of the lower quarter in chronic pain management include: lateral femoral cutaneous nerve, saphenous nerve, recurrent genicular nerve, ilioinguinal/iliohypogastric nerve, tibial nerve, and fibular nerve. Common facial and cranial nerve blocks are discussed in the head and neck section. Peripheral nerve blocks are commonly used in order to avoid systemic side effects of other medications and to decrease overall opioid use. Peripheral nerve blocks are a great alternative for anesthesia in an ambulatory setting especially as minimally invasive surgery technique continues to advance (Joshi, Gandhi, Shah, Gadsden, & Corman, 2016; Lin, Choi, & Hadzic, 2013).


Clinical features

The patient will typically describe paresthesia, hyperesthesia, allodynia, and anesthesia within the distribution of a peripheral nerve. Specifically, they will complain of a paroxysmal burning, tingling, numbness, and radiating pain. The patient may complain that specific compressive movements can increase the pain and that the pain is worse at night.


Physical examination findings

In general, the goal of the physical examination is to determine the specific involved peripheral nerve. This is done by determining topographically the dermatomal distribution of the complaint and testing for motor inhibition of the myotomes innervated by involved peripheral nerves. Two important physical examination tests to determine the dermatomal distribution are the (1) pinch and roll test for allodynia and (2) pinprick test for hyperesthesia. Special tests like Tinel’s test can determine if there is any compressive influence on the nerve. Patient’s history and physical examination findings will specify the nerve involved and the nerve’s unique properties.


Interventional procedure type

Peripheral nerve blocks are an outpatient procedure. They are either (1) a single perineural injection or (2) a continuous infusion conducted via a perineural catheter.


Brief description of procedures/image modalities used

Procedure will vary depending on indication and target nerve. Different techniques may be employed for nerve guidance such as ultrasound, which may be used to identify superficial and deep nerves. Nerve stimulation may also be used to guide catheter or needle placement. Recent studies show ultrasound guidance is more cost-effective than nerve stimulation for continuous nerve block (Chang & White, 2017; Ehlers, Jensen, & Bendtsen, 2012).



Apr 16, 2020 | Posted by in NURSING | Comments Off on Interventional Pain Management
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