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Byline: Muhammad Salim, Babur Salim and Sadia Ahsin


Objective: To compare the clinical and cost effectiveness of Psoas compartment block (PCB) and lumbar epidural over a period of one month in patients suffering from low back pain and radiclupathy.

Methods: This study was conducted at Railway Hospital Rawalpindi over a period of one year from September 2011 to September 2012. Patients of either sex between 30 to 80 years of age, full filling the study diagnostic criteria were selected by non probability purposive sampling. Patients were divided into two treatment groups. One received epidural analgesia and other received psoas compartment block. Relevant history was recorded on proforma. Pre and post treatment pain scores were recorded using VAS and Pakistan Coin Scale (PCS) at day 1, week 1, and at the end of 1 month. In group 1 PCB was administered and in group 2 lumbar epidural was given under strict aseptic measures. In each group dose of depomedrol with lignocaine was injected according to patient's weight.

Data Analysis and Result: At baseline, average VAS for group-I was 7.209 (SD = 0.640) while in group-II it was 7.310 (SD=0.680). Both the groups had similar VAS at baseline with insignificant difference (p = 0.438).

At day 1, average VAS was significantly lower (p less than 0.001) in group-I as compared to group-II i.e. 2.030 +- 0.491 vs. 3.357 +- 1.008. After one week, average VAS for group-I was 2.851 (SD = 0.609) while in group-II it was 3.810 (SD= 1.087). Group-II had significantly higher VAS as compared to group-I (p less than 0.001). After one month, average VAS for group-I was 3.060 (SD=0.625) while in group-II it was 4.333 (SD=1.004). VAS of group-II was significantly higher as compared to group-I (p less than 0.001).

Conclusion: Patients who were given Psoas compartment block were more satisfied as compared to epidural. Their VAS was significantly lower, at day one, but after one week and at the end of one month VAS/PCS was still lower in group I and it was significant. So PCB is easy to apply and it is cost effective as compare to lumbar epidural.



Low Back Pain (LBP) and sciatica continue to be a leading cause of disability in Pakistan with socio economic impact. In most cases the pain will resolve on its own within a few weeks but there is significant incidence of recurrence, usually in less than a year1.

Low back pain is usually due to disc herniation, radiculopathy or spinal stenosis2. The patient complains of pain usually on one side or both legs. Lumbar epidural with steroids are commonly used for such patients, but the response is variable3. The Psoas compartment block (PCB) is easy to employ as compare to epidural, it is also cost effective. PCB has successfully been used in postoperative pain relieve for total hip replacement4. The psoas muscle is the muscle involved with the curve of the pelvis and spine, which starts at the thoracic vertebrae to connect with lower vertebral body and transverse process. It goes past the pelvis and extends up the lesser trochanter5. When standing, it pulls the spine forward, while keeping the balance of the body when sitting, so it has an important role during walking motion. Therefore, when the psoas muscle continuously contracts from injury or stress, the vital dynamics of the pelvis, lumbar, and even the cervical vertebrae can be disturbed.

This incongruity can cause pain in the lower back, pelvis, buttocks, and the femoral region. Also there, could be a transformation in the hip joint curve, and as a result, movement can be limited when using the hip joint. Thus, when there is a problem in the psoas muscle, it can trigger a distinctive psoas gait, where the patient drags his leg while walking as the leg cannot be strongly pushed forward6.

The psoas compartment is the space located between the psoas muscle and quadratus lumborum, and is surrounded by the psoas muscle and its fascia in the front, the lumbar, and the transverse process of the lumbar, ligament, muscle, and quadratus lumborum in the back8. Within this compartment, the lumber plexus, the ventral ramus of the sacral plexus, iliohypogastric nerve, ilioinguinal nerve, genitofemoral nerve, lateral femoral cutaneous nerve, femoral nerve, obturator nerve, and parts of the sciatic nerve pass through7. The psoas compartment block is generally performed on the L3 or L4 disc and serves to block the lateral femoral cutaneous nerve, femoral nerve, and the obturator nerve, so the block is also known as the posterior lumbar plexus block. The iliohypogastric, ilioinguinal, and genitofemoral nerve can be further blocked if medication is expanded toward the cephalic and within the fascia9.

The PCB has successfully been used but very scanty literature is available regarding therapeutic effectiveness of local anaesthetic with steroids in lumbar paravertebral injections in patients with spinal stenosis, low back pain and painful lower limb radiculopathies11.

The psoas compartment block has successfully been used in low back pain however its therapeutic effectiveness compared to epidural, using local anaesthetic with steroids needs further investigation.


This clinical trial took place at Railway Hospital Rawalpindi in collaboration with Riphah International University over a period of one year. Patients of low back ache, sciatica, radiculopathy and spinal stenosis from three teaching hospitals of Rawalpindi were selected. Patients with diabetes, hypertension or any associated disease such as caries spine and hepatitis were excluded from the study. Patients were selected by non probability purposive sampling technique. They were thoroughly examined. The written consent for the procedure was taken. A total of 120 patients were enrolled and were divided two equal groups. To group-I PCB was given and the group-II lumbar epidural was given. Relevant history was recorded on proforma. VAS (0-no pain 10-maximum pain) was explained to the patients those who could not understand VAS were offered Pakistan Coin Scale10. Pre and post treatment responses were recorded on day 1, week one and at the end of one month.

Cost of required equipment for both procedures was calculated for each patient.

Technique of PCB

A number of approaches exist for psoas compartment block12, however, the approach by Capdevila and colleagues, using a nerve stimulation technique is reliable and thus employed in current study.

Intravenous access, ECG, pulse oxymetry, and blood pressure were monitored. Emergency equipment and medications were checked. The patient was placed in the lateral (Sims) position with the side to be blocked uppermost. The hip on the side to be blocked was flexed to 300 and the ipsilateral knee flexed to 900. The skin was prepared with antiseptic solution.

The site of needle insertion was determined by drawing a line connecting the iliac crests (intercristal line i.e, Toffier line). The spinous process (SPs) were marked and PSIS was identified. A line through the PSIS was drawn parallel to the line joining the SPs. The site of needle insertion became at the junction of the lateral third and medial two thirds of the line between the SPs and the PSIS and 1 cm cephalad to the intercristal line (L4). The needle was inserted perpendicular to all planes. A 100 mm stimulating needle was inserted connected to a nerve stimulator with a starting output of 1.5 mA and 2 Hz. The needle was advanced until quadriceps twitches were elicited or bony contact (presumed to be transverse process of L4) was made. If bone was encountered, the needle was withdrawn and directed caudally under the transverse process and advanced no further than 15-20 mm, until twitches of the quadriceps muscles were elicited with currents between 0.3 and 0.5 mA.

After negative aspiration, 10-15 ml 0.5% of lignocaine with 80 mg depo medrol was injected incrementally over 3-5 min with regular aspiration for blood or cerebrospinal fluid (CSF).

In some patients fluoroscope had to be used to locate L4 transverse process.

Technique for Epidural:

In lumbar epidural 18 gauge Tuohy needle was used. Third and 4th lumbar space was located and after ensuring aseptic measures Tuohy needle was passed in the inter space. Loss of resistance was tested and desired amount of local anaesthetic and depo medrol was given.

Data Analysis:

Data were subjected to SPSS version 17. Means and average values were calculated. Difference in pain relief and cost effectiveness in the two study groups was considered significant if p value was found less than 0.05 using paired sample t test.


Out of 120 enrolled patients, 67 patients from group I while 42 from group-II completed the study. No significant adverse effects of both procedures were observed. Demographic data regarding age, sex and type of disease is shown in table 1.

Table-1: Demographic data showing age, sex and type of disease in both treatment groups.

Demographic variables###Group-I (n =67)###Group-II (n = 42)###p-value


Male###35 (52.2 %)###23 (54.8 %)###0.797

Female###32 (47.8 %)###19 (45.2 %)

Age###27 (40.3 %)###24 (57.1 %)###0.8

Average weight###74 kg###72.5 kg###0.7

Mechanical Backache###21 (31.3 %)###10 (23.8 %)###0.531

Facet Joint Pain###18 (26.9 %)###10 (23.8 %)

Radiculopathy###15 (22.4 %)###9 (21.4 %)

Spondylosis###13 (19.4 %)###12 (28.6 %)

Spinal Stenosis###0 (###0%)###1 ( 2.4 %)

At baseline, average VAS for group-I was 7.209 (SD = 0.640) while in group-II it was 7.310 (SD = 0.680). Both the groups had similar VAS at baseline with insignificant difference (p = 0.438).

At day 1, average VAS was significantly lower (p less than 0.001) in group-I as compared to group-II i.e 2.030 +- 0.491 vs. 3.357 +- 1.008.

After one week, average VAS for group-I was 2.851 (SD = 0.609) while in group-II it was 3.810 (SD = 1.087). Group-II had significantly higher VAS as compared to group-I (p less than 0.001).

After one month, average VAS for group-I was 3.060 (SD=0.625) while in group-II it was 4.333 (SD=1.004). VAS of group-II was significantly higher as compared to group-I (p less than 0.001).

Epidural procedure (Approx Rs 1000/ procedure) was found more expensive compared to procedure adopted for psoas block (Rs 200/ procedure) (p=0.00).

It is important to mention that 65% patients in group-I used analgesics while in group-II, 84% of the patients used analgesics. Difference in intake of analgesic in the two groups was found to be significant (p = 0.522).


Spinal pain usually arises from damage to or degenerative changes in the spinal nerves, intervertebral discs, facet joints, muscle/fascia, and dural tissue surrounding the spinal nerve roots. Facet joints may be responsible for 14-45% of cases of LBP, most often as a result of degenerative changes or trauma that causes inflammation of the joint capsule from overloading. Degenerated and herniated discs are other common causes of LBP and sciatica. Though the mechanism is still not certain, animal studies indicate that when there is nucleus pulposus tissue in the epidural space, it induces an inflammatory response, neurotoxicity, and thrombosis, all of which can lead to nerve root ischemia and irritation. Fissured, degenerative discs are thought to cause pain by allowing growth of sensory fibers from the sinuvertebral nerve into the inner layer of the annulus fibrosis and nucleus pulposus which are normally not innervated13,14.

It remains unclear to what degree nerve root compression or irritation is responsible for radicular pain and LBP. In general, sciatica type pain is most-likely due to nerve root compromise (radiculopathy), while axial back pain is more indicative of a "mechanical origin" such as facet syndrome, discogenic pain, or muscular pain. Radicular-dominant pain is many fold more likely to respond to epidural steroid injections than back-dominant pain. Caudal and transforaminal ESIs provide strong short term relief and moderate long term relief. All techniques have limited benefit in managing post laminectomy syndrome and spinal stenosis.

Although the actual mechanism of action is not fully known, there is evidence that corticosteroids achieve pain relief by inhibition of pro-inflammatory mediators (e.g. neural peptides, phospholipase A, acid hydrolases, histamine, and kinin) and by causing a reversible local anesthetic effect (decreased sensitivity of nerve roots to irritants)12.

The epidural space is a potential space that surrounds the thecal sac circumferentially from the foramen magnum to the sacral hiatus. It is bordered anteriorly by the posterior longitudinal ligament, posteriorly by the ligamentum flavum, and laterally by the intervertebral foramina and pedicles. Its contents include neural tissue (spinal cord and nerve roots), as well as fat and vascular tissue. The posterior epidural space is highly compartmentalized with connective tissue planes and a medial divider (plica mediana dorsalis), all of which influence the direction of flow of injectate within the epidural space. In one study, 84% of interlaminar injections resulted in unilateral flow,13 which can be critical issue when treating unilateral or bilateral symptoms. Blind injections cannot confidently be placed on the right or left, or at a specific level, let alone in the epidural space14,15.

Contrast enhanced, image-guided, fluoroscopic injections are the only reliable method to place injected agents accurately in the epidural space.

Psoas muscle takes its origin proximally on the borders of the vertebrae T12 to L4. It crosses a total 8 joints including the sacroiliac joint and is attached distally on the lesser trochanter of the femur. The eight joints crosses over are from T12-L1, L1-L2, L2-L3, L3-L4, L4-L5, L5-Sacrum, Sacroiliac joint and last the hip joint. The psoas can have an effect on all of these vertebrae joints and lead to back pain. Psoas muscle often goes into spasm whenever there is any pathological change in the vertebral disc. It can create stronger lordotic curve. PCB releases the spasm and relaxes the muscle leading to relieve from back pain. Our results show the positive effects of psoas compartment block as compare to epidural. Efficacy, patient's satisfaction and safety with psoas compartment block were assessed in terms of overall reduction of pain relief and amount of analgesics, duration of pain relief and overall improvement in daily activities.

In our study majority of the patients reported either a marked relief in pain or their pain remained below three VAS for more than one month.

We used local anaesthetic (Lignocain) and depomadrol. The reason for corticosteroid therapy is preliminary from the evidence that biochemical and neurochemical inflammatory mediators may play a role in the occurrence of lumbar radiculopathy16,17. Corticosteroid also known to inhibit prostaglandin synthesis, and to repair cell mediated and immunologic responses. The other postulated actions of corticosteroids includes membrane stabilizing, suppression of neuropathies, blocking phospholipase A2 activity, and blocking nociceptive C-fibers conduction. Psoas block with steroid and local anaesthetic in patients had shorter lasting lumbar radicular pain18.

Epidural block is commonly used for low back pain. It is technically difficult as compared a to PCB. Psoas block is cost effective and can easily be learned. In our study results were slightly better in PCB as compared to epidural.

The literature is full with descriptions of epidural corticosteroid injections providing a certain level of efficacy by their anti-inflammatory, immune-suppressive, anti-edema effects, as well as the inhibition of neurotransmission within the C-fibers22-25. Local anesthetics also have been described as providing long-term symptomatic relief, even though the mechanism of action continues to be an enigma26-28. Local anesthetics have been postulated to provide relief by various mechanisms including suppression of nociceptive discharge,29 the blockade of the axonal transport, the block of the sympathetic reflex arc and sensitization,30-31 and anti-inflammatory effects32. The long-term effectiveness of local anesthetics has been shown in many previous studies as a result of local anesthetic nerve blocks or epidural injections33.

Lumbar plexus blocks produce anesthesia of most of the lumbar nerve roots and some of the sacral nerve roots. It therefore produces anesthesia to the lower extremity in the distribution of the femoral nerve, the obturator nerve and the lateral cutaneous nerve of the thigh. If anesthesia to the lower leg or posterior thigh is needed for the procedure, sacral nerve roots block must be added, typically in the form of a sciatic nerve block. The psoas compartment is a relatively large and well-defined compartment and the psoas muscle is a loosely compacted muscle. A large volume of local anesthetic agent is therefore needed to fill this compartment to produce surgical anaesthesia. We have used small doses of local anaesthetic to relieve pain of radiculopathy.


Patients given psoas compartment block were more satisfied compared to epidural as depicted by their VAS after 1 day, 1 week and 1 month duration. PCB was found easy to apply and cost effective as compare to lumbar epidural.


We are grateful to HEC for their financial support (project no. 2029/R and D/HEC 2011) to conduct this study.


1. James D. Artuso Back pain and needles: Epidural steroid injections for radicular boverk pair. JLGH 2007; (2):1-2.

2. Rosen CD, Kahanovitz N, Bernstein R, Viola K. A retrospective analysis of the efficacy of epidural steroid injections. Clin orthop Relat Res 1988; 228: 270-2.

3. Brooks DM. Psoas compartment block. CRNA. 2000; 11: 62-5.

4. Capdevila X, Macaire P, Dadure C, Choquet O, Bibovlet P, Ryckwaert Y et al. Continous psoas compartment block provide optional analgesia after hip arthoplasty. Anesth Analg 2002; (94): 1606-13.

5. Bogduk N, Pearcy M, Hadfield G. Anatomy and biomechanics of psoas major. Clin Biomech (Bristol, Avon) 1992; 7:109-119.

6. Travell JG, Simons DG. Myofascial pain and dysfunction: the trigger point manual. Baltimore: Lippincott Williams and Wilkins; 1983; 89-109.

7. Brown DL. Atlas of regional anesthesia. 3rd ed. Philadelphia: Elsevier / Saunders; 2006. Psoas compartment block; pp. 95-96.

8. Torres GM, Cerniliaro JG, Abbitt PL, Mergo PJ, Hellein VF, Fernandez S, et al. Iliopsoas compartment: normal anatomy and pathologic processes. Radiographics. 1995; 15:1285-1297. [PubMed]

9. Mannion S. Psoas compartment block. Contin Educ Anaesth Crit Care Pain. 2007; 7:162-166.

10. Salim M, Pakistan Coin Pain Scale 1993; 52(3): 373-74.

11. Khan MU, Hussain SZ. Role of Psoas Comptment and coudal epidural steroid injection in spinal stenosis patients associated with low back pain and lower limb radiculopalhy. J Pak Med Assoc 2008; (58): 490-93.

12. Award IT, Duggan EM. Posterior lumbar plexus block, anatomy, approach and techniques, Reg Anaesth Pain Med 2005; 30: 143-9.

13. Botwin KP, Natalicchio J, Hanna A. Fluoroscopic guided lumbar interlaminar epidural injections: a prospective evaluation of epidurography contrast patterns and anatomical reviewof the epidural space. Pain Physician. 2004; (7):77-80.

14. Sung MS. Epidural steroid injection for lumbosacral radiculpathy. Korean J Radiol 2006; (7): 77-79.

15. Bartynski WS, Grahovac SZ, Rothfus WE. Incorrect needle position during lumbarepidural steroid administration: Inaccuracy of loss of air pressure resistance and requirement of fluoroscopy and epiduroscopy during needle insertion. Am. Journal of Neuroradiology 2005; (26):502-05.

16. Rinehart JJ, Sagone AL, Balcerzak SP, Ackerman GA, LoBglio AF. Effects of corticosteroid therapy on human monocyte function. N Engl J Med 1975; (30):236-41.

17. Storm PB, Chou D, Tamargo RJ. Lumbar spinal stenosis, cauda equine syndrome, and multiple lumbosacral radiculopathies. Phys Med Rehabil Clin N Am. 2002; 13: 713-33

18. Styczyski T, Parnarauskiene R, Zarski S, Kaubrys G, Klezys V, Krzemiska Dabrowska I, et al. The assessment of therapeutic effectiveness of paravertebral blockades in patients with painful radicular syndromes in discopathy and in lumbar spine spondylosis. Neurol Neurochir Pol. 1997; 31: 939-49.

19. Boswell MV, Shan RV, Everetl CR, Sehqal N, Mckenzie Broom AM, Abdi S et al. Interventional techniques in the management of chronic spinal pain: evidence-based practice guidelines. Pain Physician. 2005; 8(1): 1-47.

20. Otani K, Arai I, Mao GP, Konno S, Olmarker K, Kikuchi S. Experimental disc herniation: evaluation of the natural course. Spine. 1997; 22: 2894-99.

21. Manchikanti L. Transforaminal lumbar epidural steroid injections. Pain Physician. 2000;3:374-398.

22. Hayashi N, Weinstein JN, Meller ST, et al. The effect of epidural injection of betamethasone or bupivacaine in a rat model of lumbar radiculopathy. Spine (Phila Pa 1976) 1998; 23: 877-85.

23. Lee HM, Weinstein JN, Meller ST, Hayashi N, Spratt KF, Gebhaut GF. The role of steroids and their effects on phospholipase A2. An animal model of radiculopathy. Spine 1998; (23): 1191-6.

24. Johansson A, Hao J, Sjolund B. Local corticosteroid application blocks transmission in normal Nociceptive C-fibers. Acta Anaesthesiol Scand. 1990; 34: 355-8.

25. Pasqualucci A, Varrassi G, Braschi A. Epidural local anesthetic plus corticosteroid for the treatment of cervical brachial radicular pain: Single injection verus continuous infusion. Clin Pain . 2007; 23: 551-7.

26. Arner S, Lindblom U, Meyerson BA. Prolonged relief of neuralgia after regional anesthetic block. A call for further experimental and systematic clinical studies. Pain. 1990; 43: 287-97.

27. Wertheim HM, Rovenstine EA. Suprascapular nerve block. Anesthesiology 1941; 2:541-5.

28. Bisby MA. Inhibition of axonal transport in nerves chronically treated with local anesthetics. Exp Neurol. 1975; 47: 481-89.

29. Lavoie PA, Khazen T, Filion PR. Mechanisms of the inhibition of fast axonal transport by local anesthetics. Neuropharmacology. 1989; 28: 175-81.

30. Katz WA, Rothenberg R. The nature of pain: Pathophysiology. J Clin Rheumatol 2005; 11: S11-5.

31. Melzack R, Coderre TJ, Katz J. Central neuroplasticity and pathological pain. Ann N Y Acad Sci. 2001; 933: 157-74.

32. Cassuto J, Sinclair R, Bonderovic M. Anti-inflammatory properties of local anesthetics and their present and potential clinical implications. Acta Anaesthsiol Scand. 2006; 50: 265-82.

33. Riew KD, Park B, Cho YS, Gilula L, Patel A, Lenke LG et al. Nerve root blocks in the treatment of lumbar radicular pain. A minimum five-year follow-up. J Bone Joint Surg Am 2006; 88: 1722-5.

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Publication:Pakistan Armed Forces Medical Journal
Geographic Code:9PAKI
Date:Sep 30, 2013

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