Musings May

Caudal vs. Transforaminal Epidural Steroid Injections as Short Term Pain Relief in Lumbar Spinal Stenosis Patients with Sciatica, Ploumis et al. Pain Medicine Vol 15. No. 3 2014 pp 379 -85.

This study looked at 31 patients with 11 receiving caudal injection and 20 receiving transforaminal injection. 90% of the transforaminal patients had halving or more of their pain at six months, compared to the caudal group of 55%. 100% of the patients with transforaminal injection had a significant improvement in their Oswestry (greater than 15 pt reduction) at six months, whereas only 27% of the caudal epidural patients achieved that endpoint.

Comment: This is suggestive, but not absolute proof, that transforaminal should be the route of choice for patients such as these. That is because it was not a randomised double blind allocation as one Doctor in one hospital performed it caudally and another Doctor in another hospital performed it transforaminally and so we are also comparing two Physician’s techniques, etc. However, in those subset of patients with spinal stenosis who present with radicular symptoms, transforaminal approach should be the preferred option.

Intracranial Pressure in Unresponsive Chronic Migraine, De Simone et al, Journal of Neurology 30^th April 2014

This is a fascinating study from the Headache Centre based at University Federico II of Naples. They looked at 278 patients treated between 2004 and 2011 who had chronic daily migraine and they were treated along standard clinical pathway. 80% of them responded with significant improvement in terms of institution of prophylactic anti-migraine medication with elimination of agents known to promote chronic daily headache (opioids and/or regular Triptan use). They were left with 20% of patients who were unresponsive and these patients had all had initially episodic migraine that had transformed into chronic daily headache. Magnetic Resonance Venography was performed and 90% of the patients were found to have abnormalities which included such as bilateral transverse sinus stenosis/flow gaps, unilateral transverse sinus gaps/stenosis. These patients with positive pathological findings on their Magnetic Resonance Venography underwent therapeutic CSF withdrawal via lumbar puncture (44 patients) and 70% of patients had a reduction in their chronic headache and this was maintained at three months in 45% and at four months in 39%. Specifically, they withdrew 6ml of CSF for patients with an opening pressure of less than 200mm of water and in patients with an opening pressure greater than 200mm of water (the majority) they withdrew 2ml at a time until either the opening pressure had reduced to 100mm of water or 30ml of CSF had been withdrawn. 70% of patients had a time limited orthostatic headache after CSF withdrawal that lasted eight days (range 1 – 30 days). Some patients had immediate resolution of headache and other patients had to wait for their orthostatic headache to abate before they saw improvement.

Comment: This is a landmark paper that will surely stimulate further research in this area as it may open up a new avenue of treatment for patients with truly refractory chronic daily headache who essentially at this stage only have occipital nerve stimulation as a rescue therapy. The paper of course raises more questions than it answers and exactly what portion of these unresponding chronic daily headache patients in fact have intracranial hypertension in the absence of papilloedema is unclear but certainly appears as if there is a significant proportion who do. This may open up the ability for them to be treated with either three monthly therapeutic CSF withdrawal or undergo other therapeutic avenues of treatment for intracranial hypertension.

Modic Type I Changes by Vertebral Augmentation with Bioactive Resorbable Bone Cement, Masala et al. Neuroradiology 1 May 2014

This group from Rome, Italy looked at 218 patients treated with this approach. Patients had to have chronic low back pain present at rest and worsened with activity, pressure soreness over the level involved and MRI evidence of Modic Type I change. They could not include patients with radicular lower limb pain, previous spinal surgery or blocks, osteoporosis, disc protrusions or any other spinal abnormality. They injected 4ml of Cerament into the vertebral body above and below the Modic change of the disc as close to the endplate as they could achieve depositing one third anteriorly, one third in the middle of the vertebra and one third posteriorly. They report that 98% of patients showed a “good response”. Good response is not defined but I assume refers to any amount of reduction in pain from baseline. 80% showed rapid response within the month in terms of pain reduction, whereas 20% had a slower improvement with the same pain reduction evident at one year. The average decrease in the visual analogue scale was 3.4u. The average change in the Oswestry Disability Index was moving from 60 at baseline to 30 at end of one year. No data has been collected beyond one year.

Comment: On paper this would appear to represent a treatment in which all patients can have some degree of pain reduction. The average pain score at the end of one year in the cohort was a VAS of 2.8 vs. a starting VAS of 6.2. A percentage of patients had a 30% reduction in pain and a 50% reduction in pain is not specified in the paper. No long term outcomes to document the state of the affected disc has been conducted as one could potentially be concerned about discal nutrition by placement of bone cement through the vascular channels of the bone. This research should stimulate further work in this area and replication of results and potentially may represent a breakthrough in this treatment, either alone or in conjunction with the evolving work on antibiotic therapy for Modic Type I change associated with disc protusion.

Optimising the Duration of Assessment of Stage One Sacral Neuromodulation in Non-Obstructive Chronic Urinary Retention, Elneil et al, Neuromodulation January 2014 Vol 17 No 1. Pp66 – 71

This study looked at 24 female patients who had a staged procedure of implant. It took until 17 days for 90% of patients to have a positive voiding response. It took until 31 days for all patients who responded to do so.

Comment: This indicates that a trial lead needs to be in place for 30 days as a minimum to determine if a patient is responsive or not to the therapy. The percutaneous unfixed electrode is unlikely to stay in place for this duration of time and therefore patients need to either undergo a permanent lead implant with staged implant of a battery and responders or proceed directly to implant of a full system. This is an extremely important study which will change clinical practice. I believe a similar clinical study needs to be done in patients with persistent pain along the same lines.

Burst Spinal Cord Stimulation Evaluted in Patients with Failed Back Surgery Syndrome and Painful Diabetic Neuropathy, de Vos et al, Neuromodulation February 2014 Vol 17, No. 2 pp 152 – 59

This study looked at 48 patients who had received six months of paraesthesia based spinal cord stimulation and then subsequently underwent novel programming with a burst pattern of stimulation for a period of 14 days. The results of the study showed burst stimulation reduced pain compared to their normal stimulation program for almost all patients and this was a 44% reduction compared to baseline in patients with painful diabetic neuropathy, 28% reduction in patients with Failed Back Surgery Syndrome. In addition, burst stimulation caused little or no paraesthesia sensation and the majority of the patients preferred the burst stimulation pattern. Overall, approximately 60% of the patients experienced further pain reduction upon application of a burst stimulation software programming.

Comment: Burst stimulation is an interesting novel software programming that has shown some early promise in further optimising spinal cord stimulation and relief of pain. It may well become available in the Australian setting in 2015 by which time further studies should have been published. It appears that there is much room for further development of what essentially have been unchanged software parameters since the development of the technology in the late 1960s.