The complexity of the problem of pain has made it necessary for doctors to specialise in pain management. The goal of the painmanagement specialist is to help manage the pain and return the patient to a functional and reasonable quality of life. Often a multidisciplinary approach works best in the treatment of pain and setting up of pain management centres has been recognised internationally as a medical landmark phenomenon. Often, pain management clinics provide relief to people with chronic and acute pain when every other part of the health care system has given up.

Our approach begins with a comprehensive initial assessment to ascertain the type, cause and severity of pain as well as the functional and psychological disability. A multi-modal treatment plan is then formulated and individually tailored for the patient.

Analgesics include paracetamol, NSAIDS, Tramadol, Opioids and topical agents. Adjuvant drugs are needed especially in neuropathic pain and may include anti-convulsants, anti-depressants, membrane stabilisers and muscle relaxants.

Interventional pain procedures are used for specific conditions as indicated.

Sometimes it is not possible to alleviate the pain completely but reduce it to a level which allows reasonable function. Often it is not one modality of treatment that works but a combination of medical, interventional, psychological and rehabilitation techniques.

When a patient has difficulty in managing pain problems, the pain management team will hold a multidisciplinary conference to develop an individualized treatment plan involving various disciplines.

Interventional Pain Procedures
These procedures are performed under sterile technique using fluoroscopic guidance

Some of the procedures we perform include:
1. Facet joint and medial branch blocks
2. Sacroiliac joint injections
3. Epidural injections
4. Radiofrequency neurotomy for facet and sacroiliac joint
5. Epidural neuroplasty and adhesiolysis
6. Implanted intrathecal or epidural administration systems
7. Implanted spinal cord stimulators
8. Sympathetic blocks like coeliac plexus, lumbar sympathetic and stellate ganglion
9. Cranial nerve and ganglion blocks
10. Peripheral Nerve and Plexus blocks and indwelling catheters

Epidural Steroid Injection
Steroids such as dexamethasone or triamcinolone are administered via caudal, interlaminar or transforaminal routes into the epidural space.(3,4) using fluoroscopic guidance. Patients who benefit are those with radicular symptoms caused by local inflammation due to prolapsed or damaged discs, facet joint hypertrophy or trauma.

Relief is not instantaneous, but most patients report initial benefit in two to five days and maximum relief in one or two weeks after the injection.

Properly performed, controlled diagnostic selective nerve root blocks can also be an effective technique in evaluating patients with multilevel pathology to help identify the pain generator. Surgery can then be performed in selected patients at the appropriate level.

Rarely complications include dural puncture, infection, intravascular injection, air embolism, vascular trauma, particulate embolism, cerebral thrombosis, epidural hematoma, neural or spinal cord damage, and complications related to administration of steroids. These complications are minimized by careful technique, trained specialists and fluoroscopic guidance.
Fluoroscopic Image of Transforaminal
Epidural Steroids

Facet Joint Blocks
Facet joint pain may be managed by intraarticular injections of steroids, medial branch blocks or radiofrequency neurotomy of medial branches.(5,6) Utilizing traditional radiofrequency neurotomy techniques of medial branches in the cervical and lumbar regions, the evidence is strong for short-term and moderate for long-term relief.

Facet joints have been implicated as responsible for spinal pain in 15% to 45% of patients with low back pain, 54% to 67% of patients with neck pain and 42% to 48% of patients with thoracic pain.(3)

Peripheral Nerve Blocks - Occipital nerve block
Occipital nerve block is most frequently used to diagnose and treat a type of headache most likely due to occipital neuralgia or an irritation of the Greater or Lesser Occipital Nerve. This treatment has brought relief to many patients who suffer from pain caused by occipital tension headaches.

Pain relief is usually felt fairly quickly after the injection. When a local anesthetic and steroid are used, there is some initial pain relief that may then dissipate when the local anesthetic has worn off. Additional pain relief is felt roughly 48 hours later when the steroid medication begins to take effect.

Implanted Spinal Portal System
A spinal portal system is an implanted system which allows access to the epidural or intrathecal space. A port is a small disc with a raised "septum" in the center. It is easily felt through the surface of the skin. The port is usually implanted under the skin on the chest.

Attached to the base of the port is a narrow catheter. The catheter runs beneath the skin from the epidural or intrathecal space to the port. The entire system is implanted under the skin reducing the risk of infection greatly. The septum is made of self sealing material which may be punctured many times and it reseals itself instantly.

The intrathecal space is more commonly used to administer drugs in this way. It is entered using a needle guided by fluoroscopy. The catheter is then inserted through the needle and the tip positioned near the nerves corresponding to the areas of pain. Drugs infused continuously include local anaesthetics, morphine and others.

This system is more commonly used to administer drugs to control severe cancer pain which failed to be controlled by other measures.        
Intrathecal Porta-Cath System Placement
under Fluoroscopic Guidances

Intrathecal Programmable Pump
The intrathecal programmable pump is an implanted device used to deliver local anaesthetics and opioids directly into the cerebrospinal fluid. The system consists of an infusion pump, a spinal catheter, and an external programmer.

This treatment has brought relief to many patients who suffer from severe cancer pain and also from chronic and severe spasticity of spinal cord origin.

The pump is programmed immediately upon placement, before leaving the surgical suite. The effect of the medication occurs within minutes to hours, depending on the choice of medication placed in the pump. 

Implantable programmable  Intrathecal Catheter & Pump

Spinal Cord Stimulator
Spinal cord stimulation can relieve chronic pain in the back, arms or legs. It works by electrically stimulating the spinal cord. Instead of pain, the patient feels a tingling or buzzing sensation.

The spinal cord stimulation system consists of several parts:
• A battery-powered device called a pulse generator is implanted in the back or abdomen. It generates low-voltage electrical stimulation at the spinal cord through an insulated wire lead.

• A lead is implanted in the epidural space near the nerves that correspond to the patient’s areas of pain.

• An external programmer allows tuning of therapy within physician prescribed parameters to address different levels and types of pain

The spinal cord stimulator may be used for patients with one of the following conditions who have not responded well to more conservative therapies:
• Complex Regional Pain Syndrome
• Failed Back Syndrome
• Phantom Limb Pain
• Other Neuropathic Pain Syndromes

Spinal Cord Stimulation involves a two part process - implantation of temporary spinal cord stimulator trial leads and permanent implantation of a spinal cord stimulator generator if the trial is successful.

Conclusion
Effective pain management involves multiple modalities and often a multidisciplinary approach. The staff at the Pain Management Centre at the Singapore General Hospital has a vision and a mission to address effectively and comprehensively, the problem of pain among our patients.

References
1. Pain in Europe – A Report

2. Gureje O, M Von Korff, Simon GE, Gater R. Persistent Pain and Well-being JAMA 1998; 280:147-151

3. Boswell MV, Shah RV, Everett CR, Sehgal N, Mckenzie-Brown AM, Abdi S, Bowman RC, Deer TR, Datta S, Colson JD, Spillane WF, Smith HS, Lucas- Levin LF, Burton AW, Chopra P, Staats PS, Wasserman RA, Manchikanti L. Interventional techniques in the management of chronic spinal pain: Evidence based practice guidelines. Pain Physician 2005; 8:1-47. ISSN 1533-3159

4. Boswell M, Hansen H, Trescot A, Hirsch J. Epidural steroids in the management of chronic spinal pain and radiculopathy. Pain Physician 2003; 6:319-334.

5. Niemisto L, Kalso E, Malmivaara A, Seitsalo S, Hurri H. Cochrane Collaboration Back Review Group. Radiofrequency denervation for neck and back pain: a systematic review within the framework of the Cochrane collaboration back review group. Spine 2003; 28:1877-1888.

6. Slipman CW, Bhat AL, Gilchrist RV, Isaac Z, Chou L, Lenrow DA. A critical review of the evidence for the use of zygapophysial injections and radiofrequency denervation in the treatment of low back pain. Spine J 2003; 3:310-316.

7. Boswell MV, Trescot AM, Sukdeb Datta et al. Interventional Techniques: Evidence-based Practice Guidelines in the Management of Chronic Spinal Pain. Pain Physician 2007; 10:7-111