Interventional Pain Management

The algorithmic approach to interventional pain management imply to use simple, low cost and less invasive procedure at first and then more invasive and high cost ones. Usually the first interventional procedure is a diagnostic and therapeutic block. Then, depending on the site of pain; neurolysis, radiofrequency, intradiscal procedure, intrathecal pump and spinal cord stimulation would be considered [5,6].


Introduction
There are many approaches for managing patient with chronic or acute pain: pharmacologic, psychological, interventional, different medical, to call the foremost common.All of those ways has its benefits and disadvantages.Knowing the way to perform a treatment strategy is additionally critically vital.
The field of interventional pain management methods including diagnosis and treatment of pain using various techniques such as nerve blocks, anesthetic or corticosteroid injection, intrathecal opioids, methods of destruction of nerve, such as assisted radiofrequency, nerve stimulation techniques such as spinal cord stimulation and intrathecal pump.
Interventional procedures for pain management have been developed as a new technique since 1960, its progress with the efforts of John J. Bonica in 1975.Steven Waldman first used this word in 1996.Professor Raj lifelong educational efforts have devoted his career for the education and training of Interventional pain specialists around the world.What was previously the role of anesthesiologists to do such procedures is now open to many other specialists (physical medicine and rehabilitation, neurologists, neurosurgeons, and so on).Imaging techniques have become a part of this new advance and are considered a good practice for interventional procedures in pain management.There are numerous developments in our ability to image the human body during interventional procedures.These include ultrasound, fluoroscopy, CT scanning [1][2][3][4].vascular pains (Raynaud's phenomenon and disease, Buerger's disease), lower limbs profuse sweating, urogenital pain and in the lower limbs complex regional pain syndrome.Lumbar dorsal root ganglia block is effective in controlling sciatica [1][2][3][10][11][12][13]. Lumbar dorsal root ganglion block is also effective in controlling pain in amputated limbs [14,15].Lumbar, thoracic and cervical Medial Branch Block (MBB) which block nerves that innervated facet joints, reduce pain in patients with chronic facetogenic low back pain, mid back pain and chronic neck pain or cervicogenic headache.Gasserian ganglion block is effective in controlling cluster headache and trigeminal neuralgia, persistent ear pain and facial pain caused by cancer or multiple sclerosis.Sphenopalatine ganglion block is indicated in migraine headache, atypical facial pain, ocular herpes, trigeminal neuralgia and sphenopalatine neuralgia.Occipital block is useful in reducing migraine and tension headaches caused by neck problems and occipital neuralgia.nerve blocks are effective in reducing shoulder pain.Sacroiliac joint blocks are effective in lumbar pain management [16][17][18][19][20].

Neurolysis
Radiofrequency neurolysis also called ablation, denervation, rhizotomy etc.It uses heat generated by radio waves to damage specific nerves and temporarily interfere with their ability to transmit pain signals.
Conventional radiofrequency or pulse radiofrequency could be used depending to the site of procedure.In dorsal root ganglion PRF is used to prevent permanent damage due to high temperature of CRF.Temperature in PRF is below 42, and therapeutic effect of electrical field managed pain.CRF is used in MBB and its therapeutic effect is superior to PRF in this region.In mixed nerves (e.g.sciatic, intercostals, femoral, median) PRF is used.Although PRF is not destructive but effect of high electrical field at the needle tip and hot flash may have destructive effect.So it is recommended to use sensory nerve stimulation at 0.5-0.7 and not put needle into the nerve, then applied PRF [21][22][23].

Spinal Cord Stimulation
Spinal Cord Stimulation (SCS) is a method of treatment in which a surgically implanted pulse generator sends electrical currents through the spine in order to interfere with nerve impulses that cause chronic pain.The pulse generator is inserted in the abdomen, and small, coated wires run to the point in the spinal canal where the pain originates.The pain is reduced because the electrical current interrupts the pain signal from reaching your brain.This method of treatment may be recommended for people who have Failed Back Surgery Syndrome (FBSS) or severe neurogenic pain caused by a degenerative spine condition.This method is also effective in neuropathic and ischemic pain [3,12,24].

Implantable Pumps
Patients who are suffering from terminal illnesses like cancer and patients with intolerable pain, who cannot tolerate side effects of the higher-dose oral medications, are candidate for these pumps.This type of therapy is generally recommended for individuals with a life expectancy of greater than six months.
By implantable pumps, opioids and other approved medications, such as clonidine, Ziconotide, anesthetic drugs such as bupivacaine, tetracaine and ropivacaine pumped directly into the spinal cord.
Intrathecal pumps deliver small doses of medication directly to the spinal fluid.It consists of a small battery-powered, programmable pump that's deep-seated underneath the subcutaneous tissue of the abdomen and connected to a small catheter tunneled to the site of spinal entry.A pain pump may be a treatment option if all other traditional methods have failed to relieve symptoms [10,12].

Kyphoplasty and Vertebroplasty
vertebroplasty and kyphoplasty are similar medical spinal procedures in which bone cement is injected through a small hole in the skin into a fractured vertebra with the goal of relieving back pain caused by vertebral compression fractures, and is also sometimes performed for other conditions that may have led to a spinal fracture (e.g.tumor metastases to vertebral).Kyphoplasty is a variation of a vertebroplasty which attempts to restore the height and angle of kyphosis of a fractured vertebra.The procedure generally includes the employment of a small balloon that is inflated in the vertebral body to create a void within the bone prior to cement delivery.These techniques not only control pain, but also adjust vertebral high and prevent complication due to kyphosis.They are minimally invasive and are suitable in older patients with co morbidity [3,25].

The Intradiscal Methods
The methods are used to control pain from herniated discs and sciatica pain.This technique is less invasive and a needle enters into the disc space from skin and relieves pressure inside the disc (nucleoplasty, decompressor) or can cause nerve neurotomy (radiofrequency, laser) or both.
In percutaneous disc nucleoplasty pulses of radio waves sends into the nucleus of a herniated disc.These radio waves vaporize little amounts of disc material, making associate empty area among the disc and the pressure on nerve roots or the spinal cord will disappear, providing immediate pain relief.
In dekompressor discectomy a small needle is advanced to the herniated disc guided by fluoroscope.A probe with a rotating tip is then inserted through the needle to achieve the ruptured intervertebral disc, once the probe is turned on, its tip drills away a part of the disc nucleus, making area for the ruptured intervertebral disc wall and relieving pressure on the nerve Percutaneous intradiscal radiofrequency thermo coagulation is a procedure that allows the controlled delivery of heat to the intervertebral disc via an electrode or coil and coagulated disc.
Laser disc decompression has been used to deflate a disk somewhat.An optical fiber inserted into the disc by a needle.The heat created takes out a small amount of the middle of the disc.The warmth might cut back pain by moving the chemical structure within the disc [3,12].

Caudal Neuroplasty
Adhesions and scarring as epidural fibrosis may occur after spinal surgery that restricts the free movement of nerve roots, causing tethering and leading to pain.Caudal neuroplasty is introducing a catheter into the epidural space at caudal region.It has been shown to assist diminish scar formation, thereby decreasing the number of irritations on the spinal nerves Today's the term of epidural adhesiolysis is used.This procedure is performed not solely in caudal regions of the spine, however additionally within the cervical, thoracic and lumbar regions.It has evolved over the years as an important treatment option for patients with intractable cervical, thoracic, and low back and leg pain too [3,11].

Ultrasound Guided Pain Management
Interventional procedures in pain medicine are performed under fluoroscopy or CT guidance.US is used almost for every block which could be done under fluoroscopy or CT guidance.Some procedure like TAPB (Transverse Abdominal Plane Block), illioinguinal and iliohypogastric block, a rectus sheath block could be done only by the US [26].Interventional block in thoracic region due to possibility of needle puncture of pleura is mostly done by the US.
US systems are more available and cheap these days.Transportable devices give high resolution and quality pictures.This device is available in almost every hospital.Potential advantages of ultrasound are: no hazard of radiation exposure, it could be done in every position, visualization of nerves and surrounding structures: vessels, muscles, bone and viscerapleura, lung, peritoneum, bowel, diagnostic recognizing anatomical variability and pathology real time image of needle, needle nerve contact and inject it spread, reduce complication: nerve injury, vessels puncture, pneumothorax etc., higher success rate, quicker onset, reduces performance time, reduce volume of local anesthetic [27][28][29][30][31][32].

Conclusion
Interventional pain management is an effective pain control method .Physicians must be familiar with its techniques and their application, as well as full assessment of painful cases.Using these methods at the appropriate time is very useful in controlling pain.These methods are useful in the management of persistent pain.And not only improves the quality of life but also helpful in reducing opioid use.