1. Role of Imaging in Minimally Invasive Spine Interventions Abstract/Submission No: 2958 Authors: N Peri, R Rojas, J Nagda Beth Israel Deaconess Medical Center, Boston, MA

2. PURPOSE (a) To describe the different types of minimally invasive spine interventions useful in the management of pain (b) the role of different imaging modalities in planning and performing procedures (c) the associated complications

3. INTRODUCTION Spinal pain is a very common condition resulting from a variety of causes and significant impact on the quality of life. Most patients with spinal pain are treated conservatively with analgesics and/or physical therapy. Some patients need surgery based on the etiology of spinal pain. However, surgical procedures are associated with risks and complications and variable in results. Minimally invasive conservative treatment procedures can be performed to relieve symptoms and in some patients can be tried as alternative or prior to surgery.

4. MINIMALLY INVASIVE SPINE PROCEDURES There are different types of minimally invasive spine interventions that are performed for relief of pain, neuropathic symptoms, etc. These include (a) neural blocks (epidural blocks, foraminal or nerve root blocks, facet blocks, Sacro-iliac joint injection (b) radiofrequency nerve ablation, (c) spinal cord and peripheral nerve stimulation (d) vertebroplasty, kyphoplasty (e) discal procedures such as discography, percutaneous disc ablation, percutaneous disc decompression, etc.

5. AGENTS FOR NEURAL BLOCKS AGENTS USED FOR NEURAL BLOCKS LOCAL ANESTHETICS: Lidocaine (fast acting, low toxicity), Bupivacaine (long acting, longer delay and more toxic) CORTICOSTEROIDS: Long acting steroids (1-6 weeks)- Cortivazol, Betamethasone, Prednisolone CONTRAST AGENTS: To identify the needle location on imaging Non-ionic iodinated contrast agents similar to myelography- Iopamidol

6. CONTRA-INDICATIONS Contra-indications: coagulopathy, local infection, motor deficit, conus medullaris symptoms; appropriate precautions to be taken if history of allergy, diabetes, Cushing syndrome, congestive cardiac failure, etc.

7. Some of the procedures are briefly described in the following slides. Details about the actual performance of the procedures and complications can be found in detail in textbooks of Pain Medicine.

8. EPIDURAL BLOCKS Epidural space is located between the periosteum of the vertebral component and dura and contains fat, connective tissue, vessels and nerves. Epidural block can be performed as single injection of local anesthetics or or as prolonged administration of drugs or electrical pulses through an indwelling catheter into the epidural space. Injection into anterior epidural space is performed through foraminal approach and into posterior epidural space through inter-laminar space. Caudal epidural injection – injection below S2 level

10. Epidural blocks [Contd.] Indications: Disco-radicular pain, spinal stenosis, facet arthropathy with significant foraminal narrowing, postoperative fibrosis, adhesive arachnoiditis Complications: Vagal reaction, pain, transient motor weakness, inadvertent injury to nerves or cord or vascular structures, bleeding, infection, etc.

11. FACET BLOCKS Facet joint is is well innervated by nerves that can get irritated and result in pain –facet joint syndrome. This can occur with degenerative arthritis, inflammatory arthritis, synovial cyst or repeated micro trauma from motion. Facet block with injection of anesthetics or steroids into facet joint may help in pain relief in appropriately selected patients. For C1-C2 facet injection-prone position For all other cervical levels: lateral access

12. Indication: Facet joint syndrome from degenerative or inflammatory changes, cervico-brachial radiculopathy; pain with or without radiculopathy, local paraspinal stiffness Complications: Vagal reaction, pain, inadvertent injury to nerves or vascular structures, bleeding, infection, etc.

13. FACET JOINT INJECTION

14. NERVE BLOCKS Spinal nerves and branches can be irritated by inflammatory and pain mediators from adjacent degenerative and inflammatory changes in the disc and spine and result in spinal pain. Nerve blocks are selective injections into the nerve or its branch that is thought to be the cause of the pain. Unlike epidural and facet joint injections where the injected material can spread more diffusely into the injected space and provide more diffuse pain relief, nerve blocks are more selective as targeted onto specific nerve or its branch. However, this can also pose greater risk of damage to the injected nerve.

15. MEDIAL BRANCH BLOCK

16. NERVE BLOCKS [CONTD] Cervical level: CT guidance better than fluoroscopic guidance to avoid vascular injury Needle tip advanced from the anterior aspect of facet joint into the foramen to inject Dorsal/Thoracic level: Needle tip advanced to the inferior part of the rib; can be done under fluoroscopic guidance. Lumbar and Sacral: Needle tip projected below the pedicle on oblique “Scotty dog” projection and should not progress beyond the inner part of the pedicle.

17. Radiofrequency Ablation Selective nerve roots, ganglia and sympathetic chain can also be targeted by radiofrequency ablation to provide pain relief, more permanent than steroid injections. New radiofrequency generators use pulsed radiofrequency waves without over heating the tissues compared to some of the older generators. Certain chemicals such as alcohol can also be used for chemical ablation of the nerves and ganglia.

18. RADIOFREQUENCY ABLATION

19. SPINAL CORD STIMULATORS Spinal cord stimulators are placed through percutaneous approach with the tip of the leads into the spinal cord and can help in pain relief. However, these preclude further imaging with MRI as contra-indicated.

20. VERTEBROPLASTY Vertebroplasty is injection of bone cement –poly-methyl- methacrylate (PMMA) under imaging guidance ( fluoroscopic or CT guidance) into a collapsed vertebral body to strengthen it and relieve pain in patients with compression fractures. Certain lesions such as moderate-large hemangiomas can also be treated by vertebroplasty if resulting in pain. Kyphoplasty involves introducing and inflating a balloon into the vertebral body and then injecting the material. These can be performed through transpedicular approach bilaterally or oblique unilateral approach. Trans-oral approach can be used for C1&C2 levels with appropriate precautions.

21. VERTEBROPLASTY [CONTD] Complications include perivertebral leakage, embolism of cement particles into adjacent venous structures or beyond, inappropriate needle placement into vascular structures and resultant consequences.

22. MINIMALLY INVASIVE SPINE PROCEDURES [CONTD] Vertebral and disc biopsy is commonly performed under imaging guidance (usually CT) for diagnosis. Various types of discal procedures can be performed for pain relief though not commonly performed.

23. ROLE OF IMAGING Pre-procedural testing and planning: Plain radiographs are usually performed as screening for non-specific spinal pain. CT has higher spatial resolution and provides greater detail of osseous structures, traumatic and degenerative changes and osseous lesions. MRI provides details about marrow changes that can be seen with degenerative or inflammatory/infectious processes, details about nerves, cord and soft tissues.

24. ROLE OF IMAGING [CONTD] The different modalities complement in the evaluation of spine in patients with spinal pain and help in planning and performing appropriate procedures. It is important to label and number the spine on the imaging studies to perform procedures at the correct and clinically appropriate levels and avoid wrong-level procedures, in particular in patients with transitional anatomy.

25. FACET JOINT CHANGES Sagittal STIR MR sequence: Edema in and around facet joint with small synovial cyst posteriorly

26. Lumbar spinal stenosis Multilevel, multifactorial degenerative changes predominaly related to discs, facets and ligamentum flavum resulting in moderate- severe spinal canal stenosis with compression of cauda equina nerves

27. Subarticular disc extrusion - Sagittal T2W MR sequence

28. Foraminal stenosis by disc and facet degenerative changes- Sagittal T2W MR

29. CT- SAGITTAL 2D AND 3D REFORMATIONS IN POSTOP SPINE SHOWING HARDWARE AND OSSEOUS DETAILS

30. S/P EPIDURAL INJECTION: AGGRAVATED PAIN AND INABILITY TO MOVE Sagittal MR images show a posterior epidural collection without enhancement that can related to focal accumulation of injected material or blood or a combination of both.

31. ROLE OF IMAGING [CONTD] For most of the spine procedures described above, X-ray fluoroscopic guidance is used for needle placement and injection of material. The equipment is easily available and less expensive with low radiation dose. However, limitations are lack of real time information about soft tissue and vascular structures and certain osseous details.

32. EPIDURAL INJECTION – FLUOROSCOPIC GUIDANCE

33. Lumbar medial branch injection - multilevel

34. Lumbar medial branch injection – multilevel [Contd]

35. VERTEBROPLASTY UNDER FLUOROSCOPIC GUIDANCE

36. ROLE OF IMAGING [CONTD] Advanced methods such as intra-operative CT, MRI/CT image registration, 3D visualization and robotics for percutaneous placement can be very helpful in better localization and guidance for performing the procedures. However, these are not widely available for routine use.

37. ROLE OF IMAGING [CONTD] Imaging is also helpful in the assessment of some complications and followup evaluation. Epidural hematoma, infection, abscess can occasionally occur as complications. MRI is very helpful in the evaluation of these complications. Progression of degenerative changes and vertebral height loss after vertebroplasty can be performed by radiographs, CT or MRI.

38. CONCLUSION The present educational exhibit describes briefly the different types of minimally invasive spine interventions for pain management, the role of different imaging modalities and associated complications. Categories: SPINE, Intervention (e.g., Vertebroplasty, Biopsy, Pain Management)

39. REFERENCES 1. A.D. Kelekis, T. Somon, H. Yilmaz et al. Interventional spine procedures. European Journal of Radiology 55 (2005) 362-383 2. K. Cleary, M. Clifford, D. Stoianovici et al. Technology Improvements for Image-Guided and Minimally Invasive Spine Procedures. IEEE Transactions on Information Technology in Biomedicine Vol 6, No. 4 December 2002 3. Reddy AS, Dinobile D, Orgeta JE, Peri N. Transoral approach to CT-guided C2 interventions. Pain Physician. 2009 Jan-Feb;12(1):253-8.

40. REFERENCES [CONTD] 4. Diagrams- Internet search http://www.thespinecenter.com/EpiduralSteroidI njectionhttp:// http://www.thespinecenter.com/EpiduralSteroidI njectionhttp:// http://southlakepainrelief.com/chronic-lower- back-pain/lumbar-facet-injection/ https://www.preferredpaincenter.com/medial- branch-block.html https://www.preferredpaincenter.com/medial- branch-block.html www.floridapainreliefgroup.com/florida-pain- treatments-procedures/radio-frequency- ablation/

41. THANK YOU