Interventional Pain Management Low Back Pain

Interventional Pain Management of Low Back Pain Low back pain is defined as acute/ sub acute or chronic discomfort localized to anatomic area below the posterior ribs and above the lower margin of the buttock line. Back pain is most expensive health care problem because it affects 20 to 50 years age group which is the most productive age. Eighty-five percent of our population suffers at least one episode of back pain a year. Most of them (Between 75% and 90%) resolve with in 2-4 weeks time and, about 5% to 10% of LBP patients required Interventional management however, degree of invasiveness and costs of different treatment modalities varies. Interventional Pain Management is some minimally invasive procedures (procedures including percutaneous precision needle placement, with placement of drugs in targeted areas or ablation of targeted nerves) which gives permanent/long term pain relief. It fills the gap between pharmacologic management of pain & operative procedures. This new discipline of medicine devoted to the diagnosis and treatment of pain and related disorders by the application of interventional techniques in managing sub-acute, chronic, persistent, and intractable pain, independently or in conjunction with other modalities of treatments. Mechanism of Action: IPM procedures acts through different mechanism of actions • Targeted delivery of drugs. • Aims to correct the pathology • Blocking of nerve signals • Neuromodulation and correction of neuropathy Low Back Pain is multifacorial having a long list of causes however, 4-5 major causes contribute to more than 90% of LBP. Major Causes of Low Back Pain: 1. Facet joint arthropathy 15-45% 2. Intervertebral disc disruption 25-40% 3. Sacro-Iliac joint arthropathy 15-30% 4. Disc prolapse / herniated disc/ slipped disc-5% 5. CRPS/ RSD 2-8%

Other causes of Low Back Pain 1. 2. 3. 4. 5.

6. 7. 8.

Osteoporotic Compression fracture 3-5% Other Fractures <1% Fibromyalgia & Myofascial Pain 2-5% Spinal canal stenosis 2-3% Spondylolisthesis 2-3% Tumor <1% Infection <1% Failed Back FBSS <1%

Approach and Decision making in IPM for Low Back Pain: The important point during management of LBP is to remember that, the positive finding in X-ray and MRI may not be indicative of pain pathology. It has been observed that in healthy volunteers without any symptoms of LBP, positive MRI finding may be seen in 20-50% patients showing various degree of degenerative disc pathology. Contrary to this, it is also possible that patients suffering with severe LBP, X-ray/CT/MRI or other conventional tests may not be able to diagnose the condition which is causing pain. A stepwise approach (An algorithmic approach) should be adopted to manage low back pain as it helps in reducing the economic burden and degree of invasiveness of the procedure. It also helps in practice of evidence based interventional pain management. Therefore, before proceeding for any intervention, differentiation of non-specific and uncomplicated pain should be done from radicular symptoms and alarming symptoms (Red Flag Signs) that need a referral to a spine surgeon. RED FLAG SIGNS:

• Possible fracture, • Signs of tumor or infection. • Bladder or Bowel dysfunction. • Severe or progressive neurological dysfunction in the legs. • Major motor weakness in quadriceps, plantar flexors, evertors, and dorsiflexors.

Low Back Pain Management Algorithmic approach*

Fig-2 Low Back Pain Management Algorithmic approach

Why to do interventions in spinal pain? Low back pain is a dynamic situation where acute pain have tendency to change in chronic pain. Longer the duration of nerve root irritation pain, more the incidence of neuropathic component of pain. Constant inflammation & irritation of the root can initiate the process of central sensitization. Disabling pain, Paresthesia can deteriorate the quality of life significantly. Interventions are used to diagnose (pin point the origin of pain) and than manage them accordingly.

Diagnostic IPM Procedures for Low Back Pain: • Facet joint block • Provocative discography • Epidurogram • Epiduroscopy • Selective nerve root block • SI joint block • Sympathetic Nerve Blocks Therapeutic IPM procedures for Low Back Pain: • Prolotherapy & Prolozone therapy • Epidurolysis • Epiduroscopy • Ozone nucleolysis • Percutaneous Discectomy/ Decompression • Percutaneous Vertebroplasty • Implantable drug delivery system • Spinal cord stimulator Structures Responsible for Low Back Pain

Interventional Procedures in Low Back Pain Lumber Discogram • Discography is a provocation test to diagnose discogenic pain which is responsible for LBP in 20-26% patients. A 22 WG long sterile spinal needle is placed into the center of the Intervertebral disc (IVD) under fluoroscopic guide and radio-opaque contrast is instilled to provoke pain, and to assess radiological disc morphology. Radiopaque contrast Iohexol (omnipaque) is injected in 0.05 ml aliquots and developed pressure and pain is recorded above the opening pressure (pressure at which contrast starts appearing in disc, it is about 15psi in prone position) by special pressure monitor. The interpretation is done as: <15psi above opening pressure ----- Chemically sensitive disc 16-50psi above opening pressure--- Mechanically sensitive disc 50-90psi above opening pressure----- indeterminately sensitive >90psi above opening pressure------ Normal Disc

Discogram; contrast seen in the disc

Disc pressure monitor

Other disc procedures Intervertebral disc has two parts; outer fibrous ring Annulus fibrosus which is supplied by vertebral nerves (SVN), Gray rami(GR),& Sympathetic nerves (SC) responsible for LBP and nucleus pulposus which it self is free of nerves but when comes in contact with either nerve roots or outer layer of fibrosus, causes sever inflammation and pain. This happens when fibrous ring is torn due to degeneration or trauma.

Nucleus Pulposus

Annulus Fibrosus

Stages of Disc Degeneration Pain Producing condition of disc and indicated IPM procedures: Condition of disc Disc disruption; small tears in annulus Prolapsed disc Extruded disc Sequestered disc

Cause of pain Pulposus irritating nerves & inflammation Pressure on nerve roots Physical pressure on nerve root and inflammation Physical pressure on nerve root and inflammation

Procedure Epidural steroid injection, Intradiscal RF, Intradiscal Electrothermal Therapy (IDET) Trans Foraminal steroid, Ozone nucleolysis, RF,IDET, Percutaneous Discectomy, Trans Foraminal steroid, Ozone nucleolysis, RF,IDET Percutaneous Discectomy, Trans Foraminal steroid, Ozone nucleolysis, RF,IDET (Results are less satisfactory )

Lumbar Facet Joint Block Lumber zygopophyseal joints (Facet joint) are synovial joints supplied by two medial branches of dorsal rami, one at the same level and other from one level up. Diagnosis of pain due to facet joint is done by blocking these nerves with local anaesthetic and, once confirmed radiofrequency ablation is done for prolonged pain relief. Steroid mixed with local anaesthetics can also be given either in or around the affected joints to treat LBP but duration of pain relief is short lasting. Under fluoroscopy and Patient is in prone position facet joints are focused by getting “Scottie Dog” appearance where superior and inferior articular process of facet joint is seen as two ears of the dog. A 22 WG spinal needle is directed towards the eye of dog to block the medial branch and between ears to enter in the joint capsule.

“Scottie Dog”

“Scottie Dog” View

Radiofrequency Ablation of Medial Nerve To get longer pain relief due to facet joint involvement, medial branch supplying the facet joint is treated with radio waves and procedure is known as radiofrequency ablation. With the help of thermocouple radio waves are focused on affected nerves. Due to heat generated and inherent properties of radio waves Neuromodulation occurs in the nerves and pain signals are blocked for 12-16months. A precaution is taken while radio-ablating the sensory nerves that motor fibers should not be affected.

Lumber Selective Nerve Root Block and Root Adhesinolysis Lumber dorsal and ventral root arise from the spinal cord and join together to form spinal nerve in intervertebral foramen. The cause of radicular pain is stretch and ischemia of nerve root because nerve root is surrounded by inflammatory deposits or adhesions which prevent the movement of that root during movement of body. Interventional procedures are used to reduce the edema around the nerve root and make it free to move in and out of foramen when nerve movement is required. The affected nerve root is targeted in upper and outer quadrant of foramen. This procedure is diagnostic as well as therapeutic in lumber radicular pain. Local anaesthetics are injected in affected nerve root; if pain is relieved than steroid (Depomaderol 20mg for each root) mixed with 1-2ml local anaesthetic is injected near the nerve root through intervertebral foramen under fluoroscopic guidance. Needle position is repeatedly checked in AP, Oblique and Lateral position to confirm the needle position to avoid nerve root injury. If nerve root is entrapped by adhesion due to scar of previous surgery, a catheter can be passes along the exiting root and adhesinolysis can be done by catheter movement or by injection of hypertonic saline/ infusion of normal saline. Catheter is left for three days and removed after giving steroid plus local anaesthetic mixture to prevent further inflammation and edema. This procedure requires high degree of precision to insert the catheter at desired level and it is helped by radiopaque contrast and fluoroscopy. Before the popularity of IPM, epidural steroid was most common procedure to treat radicular pain due to nerve root compression by disc or root inflammation. Large volume of local anaesthetic and higher dosage of steroid were used to reach the targeted roots. With transforaminal approach a small amount of drug is required and results are superior to epidurals.

Trans Foraminal Selective Nerve Root Block; (L4 nerve root is seen) (S1 nerve root is seen) Caudal Decompressive Neuroplasty When lumber and sacral roots are entrapped in fibrous tissue either due to previous surgery or chronic disc protrusion resulting in inflammation and edema, a special steel catheter coated with polymer (Racz catheter) is inserted through sacral hiatus and negotiated through adhesions with the help of contrast and fluoroscopy. A mixture of local anaesthetic, steroid, hyaluronidase and hypertonic saline is injected every day for three days. The effect on adhesion can be immediately confirmed by injecting contrast through catheter and compared with previous contrast study which showed various filling defects around nerves.

Black Arrow Showing Filling Defects

Filling Defects Removed

Epiduroscopy It is the process of visualization of epidural space by fiber optic scope inserted through sacral hiatus. It visualizes adhesions, sequestrated tissues fibrosis and stenotic changes. This can be used for aspiration and tissue biopsy from diseased areas. Adhesion can be released under direct vision, epidural and subarachnoid catheter and electrodes of spinal stimulator can be placed with its guidance. Drugs can be given at targeted areas more precisely.

Vertebroplasty It is a minimally invasive percutaneous procedure in which injectable rapidly hardening polymer (bone cement) is placed in vertebral body which relieve LBP due to fracture of vertebra. • Done for vertebral compression fracture with severe pain (osteoporosis, cancer metastasis, haemangioma etc.) • 11G needle is introduced through pedicle under C-armàthen low viscosity bone cement is injected. • Caution taken so that bone cement does not come in contact with nerves in the epidural space/foramen. • It is very rewarding procedure it stabilizes the spine and gives immediate pain relief.

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givemmediate pain

Bone Cement seen in the vertebra

Kit for Vertebroplasty

Spinal Cord Stimulator: It works on the principle of Gate Control Theory of Pain where low threshold stimulation blocks the pain signals. Electrode are placed in epidural space at the level of corresponding area of pain and through implantable pulse generator electrodes are stimulated through leads connecting the electrodes and source

Evidence based practices & IPM: Before IPM in a case of LBP (low back pain) an exact etiology was identifiable in only about 15% & in the majority of cases the exact cause of low back pain was not identified. Pang WW et al & Manchikanti L et al in their study of 104 and 120 patients of LBP reported that, with IPM it is possible to pin point the cause of LBP in >85% of the cases Algorithm of indication of various interventional techniques in different LBP conditions

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Acknowledgements: Dr. Gautam Das MD, FIPP (Director Daradia-The Pain Clinic, Kolkata) Dr. Vikram B Patel MD, FIPP (Director ACMI Pain Clinic Chicago USA

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References: 1. Diagnosis of Low Back Pain without disc herniation. Pain Physician 2003; 6: 3-80. 2. Manchikanti L et al. Evaluation of the relative contributions of various structures in chronic low back pain. Pain Physician 2001; 4:308-316. 3. Pang WW et al. Application of spinal pain mapping in the diagnosis of low back pain—analysis of 104 cases. Acta Anaesthesiol Sin 1998; 36:7174. 4. Ortiz AO, Johnson B. Discography. Techniques in Vascular & Interventional Radiology 2002; 5(4): 207-16. 5. Waldman SD. Interventional pain management. 55-57, WB Saunders, 2nd Edition 2001. 6. Handbook on Interventional Pain Procedures. Gautam Das, Vikram B Patel, Kartik Babu Natrajan (Editors). Daradia-the pain Clinic Kolkata (Publication) - 1st Edition 2009. Dr Ashok Jadon, MD DipNB, MNAMS, Fellowship Interventional Pain Management Sr Consultant & HOD Dept. of Anaesthesia & Pain Clinic Tata Motors Hospital, Jamshedpur-831004, India Address for correspondence: Duplex 63, Vijaya heritage phase 6, Uliyan Kadma, Jamshedpur-831005, India Mob: +91 9234554341