Spinal Cord Stimulation- A first choice for patients with severe spine abnormalities?

This case study presents a successful implantation of a spinal cord stimulator in a patient with severe kyphoscoliosis. The patient had previously undergone three operations in order to correct the spinal abnormalities that had left her with failed back surgery syndrome (FBSS) in which neither daily pain-relief medication nor nine previous epidurals were successful in treating. Due to the patients extensive kyphoscoliosis implanting a spinal cord stimulator had a higher than usual degree of risk associated with the procedure; however with technical expertise on behalf of the surgeons the implantation was a success. The post-operative benefits for the patient were excellent in terms of pain relief and increased mobility.1

Spinal cord stimulation (SCS) is becoming an increasingly prevalent treatment for failed back surgery syndrome (FBSS).

SCS is a minimally invasive procedure in which a device is implanted on the spine with leads that extend to the nerves to inhibit pain signals to the brain.² As this is a relatively new treatment option it is becoming necessary to develop ways of overcoming certain anatomical and methodological challenges that are associated with spinal surgery for abnormal spine curvature and structure.

Ms Amal Helou, President of the Australian Pain Society and Nurse Practitioner in Pain Management said "In the short term SCS is a costly option,  and currently has limited funding available in some jurisdictions for public uninsured patients, however in the long term many patients will save money by not having to  undergo further surgery, repeated physiotherapy, ongoing medications consumption, repeated medical consultations and unnecessary suffering."

To researchers’ knowledge this case study was the first to describe the successful implantation of a SCS device in a patient with kyphoscoliosis. Two main obstacles were faced on implantation of the device;¹

• The patient had fused lumber segments which automatically ruled out placement of the leads in this section and also presented difficulties associated with lead threading.
• A major difficulty was the lack of procedural visibility due to the abnormal spine curvature. In this case it was impossible to see the leads using an oblique view therefore the surgeons needed to constantly change the angle of the fluoroscopic visualisation with each level of the vertebrae that the lead advanced to.

The 72 year old female patient had kyphoscoliosis with constant localised pain in the lumbar spine which was confirmed as chronic L4 and L5 radiculopathy by nerve conduction studies. The patient had previously undergone three spinal operations to correct her kyphoscoliosis which had left her with failed back surgery syndrome (FBSS). She had also undergone physical therapy and had nine epidural steroid injections over three sessions. Her current medication at the time of SCS implantation was gabapentin and hydrocodone, causing adverse sedation. All treatments to date had failed to relieve her pain and on initial examination the patient was unable to put pressure on her heels or toes and had very limited movement around the lumbar region.¹

Ms Helou said, "Kyphoscoliosis is not one of the more common indications for implanting spinal cord stimulation devices, however in the hands of an expert implanting physician/surgeon SCS should definitely be considered after even one unsuccessful corrective surgery."

Minimising the duration and number of procedures associated with implanting the SCS device was a major aim for this patient; as it is for any patient who has already undergone multiple spine correction operations. In order to ensure the success of the implantation, two major steps were taken:¹

• The patient remained conscious while the first device lead was fitted to the nerves. This allowed the patient to communicate to the surgeons when she felt the maximum pain relief. Her response would also dictate whether a second lead needed to be implanted. Not only does this reduce the possibility of a further procedure to change the placement of the lead but it reduces the risk of unnecessary operating time by placing a second lead.
• A permanent lead was used instead of first implanting a temporary lead for the trial period; this way if the trial period was successful no further procedures would be necessary.

The case study presented two main technical challenges that arose due to the nature of the spine:¹

• Entering epidural space. The patients L2-L5 sections were fused which excluded them from lead placement and needle entry. The epidural was inserted using a paramedian approach at the levels of L1-L2. These levels were determined to be possible candidates for lead placement after examination of the radiographs taken of the patient’s spine.
• Midline advancement of the lead to the desired column level was made difficult due to the curvature of the spine. This was overcome by rotating the fluoroscopy as each level of the vertebrae advancement.

The patient reported initial pain relief during the surgery so the second lead was not required. Significant pain relief was also reported post-surgery. By ten weeks the patient had a significantly improved disability index (from severe disability to mild disability), physical activity was increased substantially and the pain relief medication was ceased.¹

This case study has presented a condition with multiple procedural hurdles that were overcome and resulted in marked improvements in quality of life for the patient. Like this case each SCS candidate needs to be assessed thoroughly in order to identify all possible difficulties during implantation. Surgeons with technical expertise are needed in cases similar to this, when the patient’s condition presents multiple hurdles.¹

Dr John Ditton, pain management specialist and leading spinal cord stimulator implantor said, "In terms of effectiveness it is difficult to compare the use of strong analgesics to spinal cord stimulation in treating chronic pain as there have been very little controlled clinical trials conducted to directly compare the two. Compared to surgical interventions, double-blind drug trials are much easier to conduct. So although there may be more empirical evidence for chronic pain relief with medication the comparitive effectiveness of the two need to be further investigated. In situations such as this where the patient requires long term pain relief spinal cord stimulation should be favoured over epidural injections."

Dr Ditton and Ms Helou both conceded that spinal cord surgery is not a first line treatment option. Ms Helou said "Less invasive options should still be considered as the first-line treatment option for back pain. However once medication, physiotherapy and corrective surgery have been attempted and have failed, spinal cord stimulation should definitely be considered. I commend these implanters on undertaking this difficult procedure."

References

1. Atallah J, Armah FA, Wong D, Weis PA, Fahy BG. Use of spinal cord stimulator for treatment of lumbar radiculopathy in a patient with severe kyphoscoliosis. Pain Phyiscian. 2008; 11(4): 555-559.
2. Barolat G. & Sharan A. D. 2000 ‘Future Trends in Spinal Cord Stimulation’, Neurological research, vol. 22, no. 3, pp. 279 – 285.