Comparison of analgesic efficacy of transforaminal epidural steroid versus steroid with ketamine in patients with lumbosacral radiculopathy - A randomized controlled trial

Lumbosacral Radiculopathy is term used to describe the pain syndrome caused by compression or irritation of nerve roots in the lower back. It can be caused by disc herniation, degeneration of spinal vertebra, and narrowing of neural foramen. Clinical manifestations include lower back pain thatradiates to lower extremities in a dermatomal pattern, numbness, weakness, loss of reflexes. Treatment options includes conservative medical management and non pharmacological which includes physical therapy, accupunture, chiropractic manipulation etc. Nowadays interventional techniques are commonly used to treat lower back pain reducing the need for surgical interventional. Transforaminal epidural steroid injection is one such interventional technique commonly used, addition of adjuvants to these epidural steroid injections like Ketamine has shown promising results by providing better clinical outcome and reducing frequency of repeated blocks.

In our study we are comparing the analgesic efficacy of transforaminal epidural steroid injection to that  of addition of Ketamine to steroid in patients with lumbosacral radiculopathy. In our study we are expecting that addition of ketamine to steroid in transforaminal epidural steroid injection will provide a longer duration of analgesia and pain free period than administering steroid alone.

The patients will be randomly allocated into any of the 2 groups based on a computer-generated block random number table and allocation into the groups will be concealed by the Serially Numbered Opaque Sealed Envelopes (SNOSE) technique. Two groups studied in this trial include Group SN (receives transforaminal epidural steroid injections), Group SK (receives transforaminal epidural steroid plus ketamine).

Intravenous cannula will be secured, a lignocaine test dose will be given, and the patient will be shifted to the operation theatre. In the operation theatre, the patient will be positioned prone on the table with a pillow between the lower abdomen and iliac crest to reduce lumbar lordosis. All ASA (American Society of Anesthesiologists) standard monitors will be attached which includes pulse oximetry, non-invasive blood pressure and electrocardiogram. Under sterile precautions, parts will be cleaned and draped. The level and the side to be blocked will be marked and confirmed again. Level identification will be done using sequential fluoroscopic images. The true anteroposterior image will be obtained by appropriate cephalo-caudal tilt, followed by same-side (pathology side) oblique tilt to obtain the Scotty dog appearance. At the appropriate lumbar-sacral spine level (L1-S1), local infiltration with 1% lignocaine will be given in the 6 o’clock position to the pedicle on the same side. The tip of a 23-gauge, Quincke’s spinal needle will be gradually advanced from the 6 o’clock direction, towards the target inferior to the pedicle under radiologic guidance. During the procedure, the lateral view will be obtained, and the needle will advance in the anterior and superior direction of the neural foramen. Optimal needle placement for injection into the anterior epidural space is confirmed by injecting a small volume of radio contrast media under intermittent fluoroscopic imaging. The contrast material (Iohexol Contrapaque®350, 350mg/ml) 1ml will be injected to confirm the transforaminal spread along the desired nerve root and also to rule out intravascular injection under fluoroscopic guidance. Drug with a volume of 6 ml will be injected in the respective nerve root depending on the group patient belongs to. In Group SN: The Patient will receive 6 ml of study drug comprises of 0.5% bupivacaine (3 ml) with 40 mg triamcinolone (1ml) and 0.9% normal saline 2ml and in Group SK: The patient will receive 6ml of study drug comprising of 0.5% bupivacaine (3ml) with 40 mg triamcinolone (1ml) and injection ketamine preservative-free 30 mg (0.6ml) and 0.9% normal saline (1.4ml). Vitals will be monitored every 1 minute for 5 minutes on the operating table after taking the patient to a supine position. Then the patient will be shifted to the pain ward and all ASA standard monitoring will be done every 5 minutes for 30 minutes and then every hour for 3-4 hours. For both groups, following initial interventions, the patients will be advised to perform rehabilitation exercises for strengthening the back muscles based on a homogenized physiotherapy protocol. All patients will be evaluated for the reduction in the VAS score at rest and movement 30 minutes immediately following post-procedure and at 4 hours (pain ward), 24hours, 2nd week and every month for the 1st 3 months. Oswestry Disability index, and Medication Quantification Scale (MQS) will be noted at baseline, 24 hrs, 2nd week and every month for the 1st 3 months. All patients will be advised for a tablet paracetamol 500 mg thrice daily and a tablet Tramadol 50 mg SOS and the analgesic requirements in both the groups will be noted. Any patient presenting post procedure with moderate to severe VAS score >4 after two months, repeat block will be considered and noted. In case if patient is not having more than 50% reduction in VAS score from baseline, it will be considered as block failure. In case of failure rescue analgesics Tab. Tramadol 50 mg thrice daily, Tab. Paracetamol 500 mg thrice daily will be continued.