The pilot study was carried out in the Department of Anesthesiology, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Dehradun over a period of 6 months between October 2015 and March 2016 with due approval of ethics committee. This study included patients with findings of lumber disc herniation/prolapse in MRI, of either sex with age less than 65 years, having complaints of backache ± radiculopathy for more than 4 weeks duration with a positive Straight Leg Raising Test (SLRT) and not responding to the conventional treatment.

Patients presenting for epidural analgesia between October 2015 and March 2016. Exclusion criteria included patient refusal, sepsis at site of injection, any spinal deformity or fracture, raised intracranial pressure, bowel bladder involvement, coagulation disorders, fever, sepsis and use of corticosteroids by mouth or intravenous within two weeks of PRP procedure.

After fulfilling the criteria, patients were explained in detail about the treatment modality & a written informed consent was taken. Diagnostic work up included complete haemogram with ESR, coagulation profile, blood sugar, X-Ray Spine (AP and lateral view). Patients were kept nil per oral 4 hours before the procedure. Baseline Visual Analogue Scale (VAS) score [2], Modified Oswestry Disability Questionnaire (MODQ) [2], SLRT [1] and neurological examination of lower limb prior to the procedure was recorded. PRP was prepared under aseptic condition from patient own blood. About 100ml of patients own blood was taken which was centrifuged and 5ml of platelet rich plasma was prepared in blood bank.

Under strict aseptic precautions a single injection of five ml autologous PRP was administered in the epidural space via interlaminar approach with 18G tuohys needle using fluoroscopic guidance. After the procedure haemodynamic parameters were monitored and recorded every 5 minutes for 30 minutes and also for any possible complications.

Patients were evaluated after 1 hour of procedure and discharged with advice to avoid too much bending, lifting heavy weight or walking long distances and told to follow-up at 3 week and 3 month. VAS score, MODQ and SLRT were noted at all times. Neurological examination of lower limb was also done which included motor examination in form tone, power, reflexes and sensory examination.

It was seen in our study that 10 patients who underwent autologous PRP injection via lumbar epidural showed a gradual improvement of symptoms in terms of VAS scores, MODQ index and SLRT. This gradual improvement of symptoms was sustained through a period of 3 months till the patients were followed up. Apart from one patient whose VAS score was 5, rest of them showed improvement and their VAS SCORE was 4 or less than 4 at three months. For most of the patients MODQ score was less than 30% and SLRT improved to >70 at three months. It showed that the gradual improvement seen was sustained till the follow-up period of 3 months. There were no complications seen and patients were able to do their daily activities without use of pain medications [1,2 and Table/Fig-3].

Our results are consistent with study done by Akeda et al., [9]. They injected PRP into the discs of patients having chronic low back pain and Degenerative Disc Disease in one or more lumbar segments. Improvement was seen in VAS scores from 7.1±1.2 to 1.8 ± 2.0, p<0.01 and it was sustained over a period of 6 months [9].

Similarly Bodor et al., reported positive effects to single intradiscal PRP which were sustained for a period of 6-12 months in almost 2/3^rd of patients. Half of them had “excellent” and half “good” response on the basis of pain resolution and ability to return to activities of daily living and exercise [10].

In an interesting case Lemper et al., administered PRP epidurally for pain management where in the patient being treated for cervical and lumbar pain became pregnant and thus became a preferable candidate for PRP injection over epidural steroid [3].

PRP is defined as a sequestration and concentration of platelets within the plasma fraction of autologous blood. The rationale behind the use of PRP is the deliver a high concentrations of growth factors and cytokines which can improve the healing process [3].

Each platelet contains 50 to 80 alpha granules which have more than 30 bioactive proteins. These proteins play an essential role in haemostasis and hard and soft tissue healing. Platelet counts of 150,000 to 300,000/microL are considered normal [3].

Alpha granules contain numerous proteins and peptides that help in cellular migration and growth including platelet derived growth factor (PDGF), transforming growth factor (TGF-beta), insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), platelet factor 4, interleukin-1 (IL-1), platelet derived angiogenesis factor, platelet derived endothelial growth factor, epithelial cell growth factor, osteocalcin, osteonectin, fibrinogen, vitronectin, fibronectin and thrombospondin. PRP count of 1,000,000 microL is regarded as the benchmark for PRP. PRP causes a three to five fold increase in platelet concentration over baseline and exogenous delivery of activated PRP leads to platelet aggregation and clotting after approximately 10 minutes and within 1 hour approximately 95% of the alpha granule contents have been secreted [3]. The motive behind use of PRP is to increase the concentration of activated platelets at the site of chronic injury which restarts the inflammatory phase, leading to healing [3].

Tolbert et al., described a 3 patient case series in which ultrasound-guided approach was used. Both hypertonic dextrose and PRP were injected to the facet joint capsules, the sacroiliac ligaments and joint and the caudal epidural space [11].

Takeuchi et al., conducted a study related to role of PRP in axonal growth in spinal cord tissues [12]. Anjayani et al., found that perineural PRP injection around the peripheral nerves of leprosy patients with peripheral neuropathy had a positive effect on sensory function at two weeks post-injection [13]. Doss et al., reported a case showing efficacy of ultrasound- guided PRP to the distal branches of the trigeminal nerve in a patient with trigeminal neuralgia, showing that PRP played a role in myelination and potentially modulated neuronal activity [14]. A large number of patients with radiculopathy wanted alternative non-surgical treatments after failing traditional conservative measures at the spine division of physical medicine and rehabilitation clinic. Thirty of these patients received epidural PRP via the caudal or lumbar transforaminal route with volumes ranging from 2-3cc of PRP into the foramen to 6-8cc into the caudal canal. There were no complications or increases in pain [8].

Bret Ferree has used PRP to replace the blood patch used to heal the dural rent causing Cerebrospinal fluid (CSF) leak and sometimes refractory post dural puncture headache [15].

In our tecchnique we have used interlaminar approach for injecting PRP in epidural space which involves passage of a needle through ligamentum flavum. Interlaminar epidural injections have been studied extensively regarding their role in radicular pain due to disk herniation, pain due to spinal stenosis, axial back pain in the absence of disk herniation and failed back surgery syndrome. Advantages include the increased likelihood that injected PRP will reach adjacent spinal levels, the ability to treat bilateral pain and the need for a lower volume of PRP. There appears to be a good evidence for the treatment of radicular pain due to disk herniation and somewhat weaker evidence for treatment of spinal stenosis, discogenic pain and postsurgical pain with this technique [4].

The limitations of ongoing study include the gradual improvement of pain symptoms. Patients in acute pain may not get immediate effect and may need to be supplemented with pain killers for a few days post PRP injection. Second limitation is more of subjective in nature as many patients are hesitant in nature to donate their own blood. Patients need to be counseled properly pre-procedurally about benefits.

This pilot study suggests a definitive role for PRP via lumbar epidural injection for chronic prolapsed intervertebral disc patients. This needs to be further validated by doing more research by randomized controlled trials which we are doing currently.