SpineUniverse Case Study Library

Progressive Low Back Pain in an At-risk Patient

Implantable Stimulation for Increasing the Probability of Fusion Success

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A 71-year-old widowed housewife presents with a long history of progressive low back pain.  At presentation, her VAS is 8.  Onset was insidious without a clear precipitating event.  She describes her pain as deep and aching with occasional sharp exacerbation, involving the low back, bilateral buttocks and anterior thighs to the knees.  There is associated numbness and tingling of the entire lower extremities, previously attributed to diabetic neuropathy.

The patient’s medical history is significant for diabetes and diabetic neuropathy, obesity, hypertension, coronary artery disease (cardiac stent), and depression.  She does not use tobacco or alcohol. 

Bending, twisting, lifting, and other activities worsen pain.  Rest helps ameliorate symptoms.


The patient is well-developed and well-nourished with no acute distress.  She is 5’2” tall, weighs 175 pounds, with a BMI of 32.0.

  • Strength: 5/5 throughout
  • Sensation is diminished in stocking distribution below her ankles
  • Deep tendon reflexes are normal, except:
  1. Ankle jerk reflex: 0
  2. Knee jerk reflex: 1+
  • Back flexion and extension are limited due to discomfort
  • Lower back is tender and motion is guarded
  • Straight leg testing elicits back pain only
  • Antalgic gait with forward flexion

Prior Treatment

Non-operative treatment did not improve or resolve the patient’s symptoms.

  • Medications
  • Physical Therapy
  • Injections

Pre-treatment Images

Degenerative disc disease (DDD) and spondylotic changes are most apparent at L4-L5 and L5-S1 (Figs. 1, 2). Grade I spondylolisthesis at L4-L5 is evident in Figure 2.

degenerative disc disease, spondylotic changes at L4-L5, L5-S1
Figure 1

grade 1 spondylolisthesis at L4-L5
Figure 2

Sagittal (Figs. 3-6) and axial MRIs (Figs. 7-10) reveal herniated nucleus pulposus, DDD and foraminal stenosis at L4-L5 and L5-S1 (Figs. 3-6).

sagittal MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 3

sagittal MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 4

sagittal MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 5

sagittal MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 6

axial MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 7

axial MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 8

axial MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 9

axial MRI, herniated disc, degenerative disc disease, spinal stenosis
Figure 10



  • DDD and spondylosis, L4-S1
  • Grade 1 spondylolisthesis, L4-L5

Suggest Treatment

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Selected Treatment

  • L4-S1 decompressive laminectomies
  • L4-S1 posterior lateral arthrodesis with autologous bone
  • L4-S1 segmental fixation
  • SpF® Implantable Spine Fusion Stimulator

The patient was admitted for 3 days with a lumbosacral brace.  She began to participate in organized physical therapy at 6 weeks.

Surgeon's Treatment Rationale

The posterior approach allowed direct decompression and stabilization through one incision. Shorter segment surgery is symptom-specific and allows addressing of symptoms without necessarily embarking on a much more extensive correction. The use of the SpF® Implantable Spine Fusion Stimulator mitigates against age, race, post-menopausal status, diabetes, and multiple level surgical risk factors for pseudarthrosis. I have also found in my experience that fusion occurs noticeably more quickly with the use of a bone growth stimulator.


The patient’s post-op VAS is 2.

Post-operative x-rays at 6 weeks

post-operative x-ray, 6 weeks
Figure 11

post-operative lateral x-ray, 6 weeks
Figure 12

The SpF® Implantable Spine Fusion Stimulator was not removed by the patient’s choice.  I do not routinely remove the device, but allow my patients the option to remove the bone fusion stimulator via a local outpatient procedure, or to forego an additional surgical procedure.

Promotional material provided by Biomet, Inc.
BIOMET Spine and Bone Healing Technologies
Parsippany, NJ

Disclaimer: Reginald J. Davis, MD, FACS is a consultant for Biomet Spine.  He did not receive compensation for this case presentation.

Note to Patients: Your surgeon may prescribe the SpF® Implantable Spine Fusion Stimulator, an implantable electrical device that has been shown to increase the probability of fusion success.1, 2, 3, 4 Electrical stimulation therapies have been used for more than 30 years to promote spinal fusion.4, 5 Backed by clinical studies, the SpF® Stimulator is a proven, safe and effective adjunctive treatment that increases the probability of the healing of your fusion.


  1. Kane, W.J. Direct current electrical bone growth stimulation for spinal fusion. Spine (Phila Pa 1976), 1988.13(3): p. 363-5.
  2. Rogozinski, A. and Rogozinski, C. Efficacy of implanted bone growth stimulation in instrumented lumbosacral spinal fusion. Spine (Phila Pa 1976), 1996. 21(21):p. 2479-83.*
  3. Kucharzyk, D.W. A controlled prospective outcome study of implantable electrical stimulation with spinal instrumentation in a high-risk spinal fusion population. Spine (Phila Pa 1976), 1999. 24(5): p. 465-8; discussion 469.*
  4. Source: SpF® Implantable Spinal Fusion Stimulator Technical Monograph,
    BSP196276L 05/10.
  5. Dwyer, A.F. and Wickham, G.G. Direct current stimulation in spinal fusion. Med
    J Aust, 1974. 1(2): p. 73-5. P850035/S0333 SpF® PLUS-Mini (60 μA/W) and
    SpF® Plus-Mini (60 μA/M). P850035/S022 SpF®-XL IIb Implantable Spine Fusion
    Stimulator. P850035/S023 SpF®-XL IIb 2/DM and 2/DW

In vitro cellular and pre-clinical studies may not be indicative of human clinical outcomes.

*Financial: In support of their research or for preparation of this work, one or more of the authors may have received, in any one year, outside funding or grants from Biomet, EBI, LLC or Biolectron, Inc.

Indications: The SpF® PLUS-Mini (60μA/W) & SpF® PLUS-Mini (60μA/M) Implantable Fusion Stimulators are indicated as a spinal fusion adjunct to increase the probability of fusion success in one or two (1 or 2) levels - P850035/S031/033. The SpF®-XL IIb Implantable Spine Fusion Stimulators are indicated as a spinal fusion adjunct to increase the probability of fusion success in three (3) or more levels - P850035/S023.

Usage: All SpF® Implantable Spine Fusion Stimulators have only been studied as an adjunct for lumbar spinal surgery i.e., posterolateral fusion. The stimulators are designed for implantation for a period of approximately 24-weeks, assuming implantation occurs prior to the expiration "use before" date. Federal Law (U.S.A.) restricts this device to sale by or on the order of a physician. Rx Only - Prescription Only - Single Use Only - Do Not Reuse.

Contraindications: There are no known contraindications regarding the use of SpF® Implantable Spine Fusion Stimulators.

Warnings and precautions associated with the SpF® Implantable Spine Fusion Stimulator may be found online at biomet.com/stimmanuals or by calling 1.800.526.2579.

Case Discussion

Dr. Reginald Davis has presented a case of lumbar spondylosis/stenosis, which was treated with a laminectomy and fusion with instrumentation in combination with a direct current electrical stimulator. Many studies have demonstrated that successful use of direct current electrical stimulation consistently increases the probability of fusion success. The direct current stimulator creates an electrochemical reaction at the cathode, known as the faradic reaction that lowers oxygen tension, increases pH, and can produce hydrogen peroxide. The increase in pH reduces activity of osteoclasts, and increases activity of osteoblasts by making an environment that is more favorable for bone formation.

Pre-clinical in vitro cellular and in vivo animal studies, although not indicative of human outcomes have demonstrated that electrical stimulation upregulates the genes that express proteins (BMPs) which are synergistically required for bone healing. Fredericks and colleagues showed in an animal model that there was a temporal upregulation of different BMPs relative to controls with the use of DC stimulation.

In order to achieve reliable fusion, many surgeons currently use BMP-2. The high cost of this material is a limiting factor in its use, especially for multilevel fusion procedures. In addition, concerns have been raised related to site specific complications with BMP use, such as prevertebral swelling in the neck during use in cervical spine surgery. Furthermore, additional concerns include ectopic bone formation and antibody formation.

This case, presented by Dr. Davis demonstrates that electrical stimulation is a safe and established cost-effective alternative, which can be used to enhance fusion success in patients at high risk for pseudarthrosis.


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