Interventional radiology in Pain management

Radiology and international radiology in Pain management

1. Pain management DR K R MYTHILI JUNIOR RESIENT STANLEY RADIOLOGY

2. Chronic pain is a complex syndrome that is difficult to treat and closely linked to opioid use disorder (OUD), a growing public health concern. The need for pain management is growing given increasing numbers of patients living with chronic diseases such as malignancy, osteoporosis, and osteoarthritis. Interventional radiologists who perform minimally invasive treatments for chronic pain are favorably suited to provide relief and circumvent the vicious cycle of OUD.

3. Minimally invasive procedures: Vertebral augmentation Sacroplasty Thermal ablation of osseous metastasis Nerve blocks Gonadal vein embolization Knee and shoulder embolization for osteoarthritis

4. Vertebral Augmentation: Vertebral fragility fractures or vertebral compression fractures are frequent in women after menopause. Also occur in men and younger patients with risk factors for bone fragility. Non surgical management of vertebral compression fractures includes a combination of bed rest, spine support, and pain medications including narcotics.

5. Vertebral augmentation (VA) includes both vertebroplasty and kyphoplasty . Purpose - stabilize the fracture and restore spinal support , which in turn leads to a reduction in pain and improvement in quality of life. Vertebroplasty - injection of polymethylmethacrylate into a fractured vertebral body Vertebroplasty on three adjacent levels showing transpedicular needles in situ and cement being injected at the most superior level. (B) Final effect of the vertebroplasty shown in 2

6. Leakage of cement outside of the vertebral body, with extravasation into paravertebral veins. Large extravasation with penetration of cement into systemic venous circulation may result in cement pulmonary emboli . Epidural or neural foraminal extravasation may lead to compression of neural structures requiring surgical decompression. Cement extravasation into the intervertebral space to increase the risk of fractures of adjacent vertebrae post procedure. Complication :

7. Kyphoplasty refers to inflation of high-pressure balloons within the collapsed vertebral body to restore vertebral body height and reduce kyphotic deformity followed by injection of polymethylmethacrylate . More recently, several vertebral implants including stents, jacks, cages, and fracture reduction systems, have been used for VA.

8. Contraindication : Absolute: Infection, either at the operative site or in the blood stream. Relative : Presence of coagulopathy Myelopathy Neural impingement Spinal instability

9. Role of Imaging prior to VA: MRI of the spine : Edema of the vertebral body (increases the likelihood of post-procedural pain relief) and spinal canal patency are well evaluated. To exclude malignancy , discitis, osteomyelitis. Helps in pre-procedure planning. Bone scan : When MRI cannot be done. Fractures of the spine or elsewhere manifest as areas of increased tracer uptake on bone scan . CT : To identify endplate fractures , loss of vertebral body height, vacuum changes in the intervertebral discs.

10. Sacroplasty : Sacral fractures are underdiagnosed and undertreated . Risk factors: Osteoporosis Other causes of osteopenia including radiation to the pelvis, steroid use, and lytic sacral tumors . Bone scan and MRI both have a high sensitivity in the detection of sacral fracture. MRI offers the advantage of identifying alternative causes for pain . Edema - fat suppressed T2-weighted or STIR images Fracture line - non-fat suppressed T1-weighted images.

11. The procedure is usually performed in the prone position using CT guidance. Long axis, short axis, or oblique approaches can be used.

12. CT-guided balloon assisted sacroplasty

13. Complications and contraindications are similar to VA procedures . More recently, a systematic review and metaanalysis - concluded that sacroplasty is safe and effective for treatment of sacral insufficiency fractures and provides long term pain relief .

14. Thermal Ablation (TA) and Cementoplasty for Metastatic Bone Tumors: Bone metastases causing primaries: lung, breast, prostate cancers, renal cancers, thyroid cancers. Osseous metastases often reduce patient performance status and quality of life due to impaired mobility, intractable pain, and pathologic fractures . Osseous metastases are usually treated with a combination of analgesic medications, bisphosphonates and systemic chemotherapy or hormonal therapy targeted to the primary tumor.

15. Palliative TA : Much shorter response time and indicated in patients with at least moderate pain . Osteolytic, mixed osteolytic-osteoblastic, or osseous tumors with a predominant soft tissue component are best suited for TA . Prior CT or MRI - to accurately assess : The extent of disease Integrity of the surrounding cortical or subchondral bone Proximity to neurovascular and other critical structures

16. RFA vs CRYOABALATION : RFA: Most widely adopted modality. More painful , necessitating the use of general anesthesia. Cryoablation : Cost-effective Following RT much quicker pain relief . Ability to simultaneously use multiple probes to create a larger confluent ablation zone , better visualization of the ablation zone or “ice ball” on imaging. Less intra-procedural pain .

17. PET–CT scan shows a sacral bone metastasis in a 52-year-old woman with thyroid cancer. b CT-guided radiofrequency thermal ablation was done. c Complete normalization of the PET–CT 6 months after treatment

18. A 32-year-old man with metastatic RCC to the right sacrum and iliac bone (arrows) (A, B). Cryoablation was performed for pain control (C, D)

19. CT guidance is used for probe placement in the treatment of most extra-spinal metastatic bone tumors. The ablation probes may be placed directly into the lesion or through co-axial bone needles depending on the integrity of the overlying cortical bone. Ablation of metastases in axial load-bearing bones such as the spine and pelvis can be augmented by injecting polymethylmethacrylate both within and around the ablation zone ( cementoplasty ), to treat or prevent pathologic fractures.

20. A 50-year-old man with lung adenocarcinoma. A metastatic lytic lesion to the right acetabular roof resulted in mechanical pain with weight bearing (arrows) (A, B). Consolidative treatment with percutaneous cementoplasty was performed

21. Complications : Unintended thermal injury to near by structures , such as nerves and skin. Neural injury following ablation of musculoskeletal tumors may occur due to proximity of central and major peripheral neural structures to the target lesion . Several techniques, including fluid or gas dissection, balloon separation, heating or cooling systems and temperature monitoring, have been reported to protect these critical structures from thermal damage.

22. Nerve Blocks : Epidural Steroid Injection : Epidural steroid injection is one of the most common procedures performed in patients with back pain .

23. The caudal approach to epidural injection is typically performed in patients with back pain and extensive thoracolumbar fusion.

24. Patients with spinal stenosis, bilateral radicular pain, and/or multi-level degenerative disc disease receive an inter-laminar epidural steroid injection.

25. In patients with unilateral radicular pain that can be attributed to a single level disc bulge or herniation, a trans- foraminal epidural approach is utilized.

26. Lumbar epidural injections are typically performed with fluoroscopic guidance . Using CT fluoroscopy , the needle can be positioned more precisely and rapidly at the desired level. Potential problems identified prior to needle insertion - spinal stenosis and synovial cysts.

27. Cervical transforaminal epidural steroid injection (AP) fluoroscopic view of the cervical spine demonstrating a needle tip within the right C6–7 intervertebral foramen. The C7 vertebral level is identified on the image. An AP fluoroscopic view of the cervical spine demonstrating the injection of contrast medium into C6–7 intervertebral foramen, and following injection of local anesthetic.  White arrows  identify contrast spread into small vertebral veins on the patient’s contralateral side 

28. Thoracic transforaminal epidural steroid injection . An anteroposterior fluoroscopic view of thoracic spine demonstrating the needle tip within T11–12 foramen, with contrast medium outlining the T11 nerve root and lateral epidural spread.

29. Lumbar transforaminal epidural steroid injection An anteroposterior fluoroscopic view of the lumbar spine demonstrating the needle tip within intervertebral foramen at L4–5, with contrast medium outlining the L4 nerve root. A lateral fluoroscopic view of the lumbar spine showing a well-demarcated line of contrast medium indicative of ventral epidural spread from the mid-body of L5 to the inferior body of L3.

30. Intercostal Nerve Block for Post-Thoracotomy Pain Syndrome (PTPS) : PTPS is persistent or recurrent pain for at least 2 months after thoracotomy and affects approximately 50% of post-thoracotomy patients . The pathogenesis remains unclear, but PTPS is most likely from a combination of neuropathic and myofascial pain related to intercostal nerve trauma. Management of PTPS can be challenging and refractory to commonly recommended treatments including non-steroidal anti-inflammatory analgesics, opioids, gabapentin, antidepressants, and local or regional anesthesia.

31. Fluoroscopic image of a trajectory view of a T9 intercostal nerve block with the needle in position at the inferior border of the ninth rib. 

32. Intercostal nerve cryoablation to temporarily impair nerve conduction , rather than cause permanent nerve damage or injury. The post-ablation relief lasts for approximately 6-9 months in most patients. The intercostal nerve is targeted at the inferior margin of the rib and cryoablation is performed for 3 minutes at 60% of the power . Cryoablation Vs RFA: Cryoablation is better tolerated and less likely to cause neuroma formation

33. Celiac Plexus Neurolysis : The celiac plexus is a network of ganglia located in the para-aortic region of the retroperitoneum at the level of the celiac axis , with sympathetic and parasympathetic efferent fibers as well as sensory afferent fibers from the upper abdominal viscera . Celiac plexus neurolysis (CPN) is a palliative treatment option for patients with intractable upper abdominal pain , often from upper abdominal malignancies or chronic pancreatitis. Meta-analysis of endoscopic ultrasound-guided CPN reported response rates of 59% in chronic pancreatitis and 80% in pancreatic cancer.

34. CPN is most frequently performed using CT or endoscopic ultrasound guidance. CT guidance for CPN has several advantages , including accurate depiction of the needle trajectory , relationship to surrounding structures, anatomical variation in the region, and the extent of neurolytic spread, which has been shown to correlate with post-treatment response . CPN is most frequently performed via an anterior or posterior approach , but lateral decubitus, posterior intradiscal , and trans-aortic approaches have been described.

35. Procedure : Using CT guidance, 22-gauge needles are placed approximately 1-2 cm anterior to the aorta between the celiac axis and SMA. Following this, 1% lidocaine mixed with a small amount of contrast is injected to determine the region of opacification, ensure extravascular needle position, and assess whether the patient experiences pain relief from the lidocaine injection . CPN is then generally performed using absolute alcohol mixed with contrast and 0.5% bupivacaine. The injection volumes vary but are typically in the range of 20- 30 cc on each side.

36. The anterior approach to CT-guided celiac plexus neurolysis in a 65-year-old woman with metastatic biliary cancer.

37. Complications : less than 2% Minor : Temporary abdominal or back pain radiating to the shoulder Diarrhea Orthostatic hypotension Major: Retroperitoneal hematoma Abdominal aortic injury Chylothorax or pneumothorax Solid organ injury Neurological deficits

38. Superior Hypogastric and Ganglion of Impar Neurolysis : The superior hypogastric plexus is located anterior to the L5-S1 disc, and the ganglion of Impar is located anterior to the sacrococcygeal joint . These neural structures are involved in transmission of pain sensation from the pelvic organs. The pain associated with lower abdominal or pelvic malignancies can be treated with combination of superior hypogastric and ganglion of Impar neurolysis . This can be performed from an anterior or posterior transdiscal approach . The ganglion of Impar can be targeted posteriorly through the sacrococcygeal joint.

39. superior hypogastric plexus is a confluence of the lumbar sympathetic chains and comes together just anterior to the L5 and S1 bodies. It innervates the pelvic viscera.

40. T ransdiscal approach S uperior hypogastric plexus block

41. ganglion impar  is a group of  sympathetic  ganglia which are located anterior to the sacrococcygeal junction; it carries nociceptive signals from the perineum area.

42. Injectate mixture:40mg of Kenalog or Depo-Medrol (or 7.2mg of Celestone ) with 5+ml of local anesthetic (bupivacaine 0.5%). 22-25 gauge, 2+-inch needle

43. Gonadal vein embolization for pelvic venous congestion : Causes of CPP in women : Endometriosis, pelvic inflammatory disease, and pelvic varicosities. Imaging in pelvic venous congestion: Ultrasound: Dilated ovarian veins > 5-6 mm in diameter with slowed or reversed blood flow. Dilated tortuous parauterine veins with width of > 4 mm . Dilated arcuate veins communicating with bilateral pelvic varicocities across the myometrium . Associated polycystic ovaries . On CT and MRI - ovarian vein diameter > 5-6 mm. The presence of severe labial, perineal or lower extremity varicosities.

44. Medical management : Gabapentin Amitriptyline opioid or nonsteroidal analgesia medroxyprogesterone acetate gonadotropin-releasing hormone analogue

45. Gonadal vein embolization : Performed after failed medical management. Venographic diagnostic criteria for pelvic venous incompetence, which should be established prior to embolization . Additionally, a left renocaval pressure gradient > 4 mmHg may suggest concomitant renal vein compression .

46. The femoral or jugular vein may be accessed for the procedure. The gonadal vein should be embolized along its entire length to prevent residual incompetent patent segments from collateralizing with retroperitoneal veins and re-establishing the reflux circuit . A embolising agents used - vascular plugs, coils, glue, gelatin sponge or foam sclerosants . The “ sandwich” technique , where a foam sclerosant is injected between coils or plug occluders at various segments of the ovarian vein is quite common .

47. Left renal venogram - reflux of contrast in the left ovarian vein Left ovarian venogram - reflux into large pelvic veins with cross-pelvic collaterals Left ovarian vein was embolized with a sclerosant and gelatin slurry followed by metallic coils Reverse curve catheter was used to select the right ovarian vein, and embolization done.

48. venogram demonstrates reflux down and incompetent left ovarian vein. Pelvic images of the same patient demonstrates venous varicocities in the left side of the pelvis, refluxing across the midline to the right via dilated uterine veins. Platinum coils are seen in the ovarian vein which is now occluded.

49. Balloon occlusion venography of the internal iliac veins and its branches is used to map the complex venous anatomy and also for sclerosis or embolization of the incompetent veins . Embolization of pelvic varicosities arising from the internal iliac vein is typically performed using foam sclerosants without mechanical occlusion. The sclerosant is injected during balloon occlusion of the targeted branch and allowed to dwell for 5-10 minutes before deflating the balloon .

50. venogram - coronal view of left internal iliac vein, highlighting multiple outflow branches (arrows). B, Embolization of the common outflow trunk of the internal iliac venous (IIV) aneurysm with two 0.018-inch 10/4 Tornado embolization coils. C, Completion venogram revealing minimal outflow after coil embolization of the aneurysmal venous outflow branches.

51. Emerging Use of Ablation and Embolization in the Knee and Shoulder: RFA to treat chronic knee pain form osteoarthritis by targeting genicular nerves (neuromodulation). This procedure is used for a variety of conditions including: Osteoarthritis (OA) Chronic Knee Pain Degenerative Joint Disease Total Knee Replacement (before or after) Partial Knee Replacement (before or after) Patients unfit for knee replacement Patients who want to avoid a knee replacement ADVANTAGES : Inexpensive Outpatient procedure only local anesthetic Minimal risk of infection No need for blood thinners Virtually non-existent recovery period Little to no postoperative pain Can return to normal activities in a matter of days

52. Angiogenesis is known to contribute to chronic pain in osteoarthritis by enabling growth of new unmyelinated sensory nerves along their path. Transcatheter arterial embolization around the knee and shoulder using antibiotic agents (Imipenem/ cilastatin sodium) or permanent embolic microspheres (100-75 µm) . Imipenem/ cilastatin sodium is an approved antibiotic and forms 10-70 µm insoluble particles when suspended in contrast, allowing for embolization of small vessels. These minimally invasive procedures - prevent or prolong the need for major operations such as knee replacement or manipulation under anesthesia for frozen shoulder.

53. Angiography of the branches of the superior medial genicular artery shows hypervascular “ blush ” (arrow) over the medial inferior aspect of the knee. Angiography after embolization depicts the end point of “ pruning ” of the hypervascular synovium. The parent genicular artery remains patent.

54. QUIZ ( True / False ) Medications used in the nerve blocks include local anesthesia , corticosteroids , neurolytic agents . Alcohol ( 50-100% ) and phenol ( 4%-15%) are the commonly used neurolytic agents . The temperature may go upto 85 degree in conventional RF and beyond 42 degree in pulsed RF . Ganglion of impar / Walther is the termination of paired paravertebral chains which is located posterior to sacrococcygeal junction .

55. Ans : True True False - The temperature may go upto 85 degree in conventional RF and not beyond 42 degree in pulsed RF . False - Ganglion of impar / Walther is the termination of paired paravertebral chains which is located anterior to sacrococcygeal junction .

56. Name the nerve block

57. Sciatic nerve block .

58. Name the nerve block

59. Stellate ganglion / cervical sympathetic block

60. Thank you