Sciatica Following a Repeat Epidural Blood Patch

We hereby present a case of sciatica following a repeat epidural blood patch for post dural puncture headache (PDPH).

A 27 year old fit and well para 1 female (BMI 33) had an attempted difficult lumbar epidural during labour. Epidural was abandoned as the patient felt an urge to push. She had an uneventful spontaneous vaginal delivery within one hour.

She developed PDPH which was treated with an epidural blood patch (EBP) 48 hours post delivery. She felt immediate improvement with some right sided headache which resolved spontaneously. A second EBP was performed 72 hours after the first EBP for recurrent PDPH. Following the EBP she developed transient right sided headache with hypertension (Blood pressure 145/90) which resolved spontaneously.

On day five after the 2^nd EBP she was readmitted with three days history of low back ache with severe shooting pain radiating to the back of left thigh up to her knees which was worse on standing tenderness over lumbar area along with tenderness over epidural site. Her symptoms got worse over next 48 hours with shooting pain to the back of both thighs, left side worse than right. Her infection markers were within normal limits.

A contrast MRI showed blood clot in subarachnoid space from L5 to sacral canal and no mass effect or dural leak. Discs, para-spinal spaces and subcutaneous space were normal. She was diagnosed having sciatic possibly due to direct irritation with blood in Intrathecal space in absence of any nerve compression. After ruling out any surgical intervention she was started on Gabapentin titrating up to 900 mg per day and advised further follow-up and MRI. Her symptoms completely resolved over next ten days.

Discussion

Placing autologous blood in the epidural space for PDPH was first described by Gormley in 1960 using just two to three mL, with a reported 100% success rate [1].Since then epidural blood patch is a widely used technique to treat PDPH and persistent leak of cerebrospinal fluid (CSF) from the subarachnoid space. It is probably the most efficacious of therapies, although this is unproven, and plays an important part in the management of this condition. It is reported that between 61% and 85% of patients will have complete and permanent recovery from headache in less than24 h [2, 3].

Physiologic mechanisms by which the EBP is effective include a physical “patch” effect, in which injected blood directly forms a seal over a dural leak, a “pressure” effect, in which increased epidural pressure is transmitted to the cerebrospinal fluid (CSF) space, thus alleviating a component of intracranial hypotension and the attenuation of initial cerebral vasodilatation.[2]

When a complication occurs after EBP, it is occasionally difficult to determine the causative factor. It is possibly related to the initial epidural placement, a result of the EBP, or the result of both procedures. Although complications from EBP are rare, they can potentially be quite serious. The most common complaint following EBP is transient low back pain [4]. Rare complications include radicular pain [5]. Possible mechanism of low back pain includes Compression, irritation, infection and arachnoiditis [6].

Increasingly severe back or radicular pain after EBP is always abnormal, and should be thoroughly and promptly evaluated to exclude neuraxial hematomas and other serious etiologies. In patients with unresolving or worsening neurological symptoms, lumbo-sacral MRI should be performed to assess for any surgical intervention. MRI may demonstrate collections of iron-laden hematomas.

Unlike previous case reports of radiculopathy, where large volumes of blood was used for EBP, in our case, we used only 20ml autologus blood at a time and our patient did not have a haematoma or compressive myelopathy. However the cumulative volume of blood used over 72 hours was 40ml which may have contributed to the development of symptoms even though there is not enough evidence to suggest this on MRI.

Based on the MRI findings, other possible mechanism of pain in our patient would have been blood in the intrathecal space causing irritation and pressure effect even thought there were no signs of nerve root compression in MRI. But a retrospective study by Arpino I et al in 94 cases failed to demonstrate a correlation between Intrathecal spread of blood and radicular pain [7].

In summary, EPB is not without serious complications and indication for EBP should be considered case by case. Patients should be followed up for any adverse incidents up to one month as per OAA recommendations. Persistent radicular symptoms in post-EBP patients act as warning signals for compressive lumbar radiculopathy that requires active interventions including analgesics, Urgent MRI and neurosurgical consultation. It may be worth considering CT or MR myelography to confirm the ongoing CSF leak before performing the second EBP or cases where diagnosis in doubtful(8). Clinicians are urged to educate patients regarding unusual risks prior to performing EBP and to be aware of symptoms of serious injury should they arise. EBP is an invasive procedure with the potential for serious morbidity.

References

1) Gormley JB. Treatment of post-spinal headache. Anesthesiology 1960;21:565-566.

2) Duffy PJ, Crosby ET. The epidural blood patch. Resolving the controversies. Can J Anaesth. 1999; 46: 878–886.

3) Tarkkila PJ, Miralles JA, Palomaki EA. The subjective complications and efficiency of the epidural blood patch in the treatment of postdural puncture headaches. Reg Anesth. 1989;14: 247–250

4) Abouleish E, Vega S, Blendinger I, Tio TO. Long-term follow-up of epidural blood patch. Anesth Analg 1975; 54: 459-63.

5) Cornwall RD, Dolan WM. Radicular back pain after lumbar epidural blood patch. Anesthesiology 1975; 43: 692-3

6) Gupta D et al. Transient compressive lumbar radiculopathy following post epidural blood patch. J Anaesthesiol Clin Pharmacol 2014 Jan;30(1);112-4.

7) Arpino I et al. Intrathecal blood spread after epidural blood patch: can it give arachnoiditis? EJA. June 2012; 29; 118

8) C.M. Wendl et al. CT Myelography for the Planning and Guidance of Targeted Epidural Blood Patches in Patients with Persistent Spinal CSF Leakage. Am J Neuroradiol 2012 mar; 33; 541– 44.

My Learning Points

• EBP can lead to potential serious and permanent neurological complications. Hence we should consider confirming the diagnosis of PDPH with appropriate radiological investigation such as CT or MR myelogram if diagnosis is doubtful.

• Possible risk factors for neuropathy may be related to increasing volume of blood used for EBPor a repeat EBP. Hence diagnosis of PDPH should be reassessed before considering a second blood patch.

• Patient should be clearly explained about high incidence of backache following EBP.

• Patient should be informed to seek medical help promptly, should she develop adverse neurological signs.

• Prognosis and recovery following neuropathy is quite variable. Clear communication with the patient is the key in managing these cases and appropriate long term follow up at high risk clinic and pain clinic should be organised.