Is total disc replacement at C3-4 and C5-6 a suitable treatment option for a 51-year-old female with cervical degenerative disc disease, neck pain, bilateral shoulder pain, and right arm tingling, who has failed conservative management with physical therapy, injections, and medication like Tylenol (acetaminophen), and has no prior cervical surgery, but has risk factors for osteoporosis, including age and history of gastric sleeve surgery?

Total Disc Replacement at Non-Contiguous Levels (C3-4 and C5-6) Should Be Denied

The requested total disc replacement at C3-4 and C5-6 must be denied because these levels are non-contiguous (separated by the normal C4-5 level), which violates absolute FDA approval criteria and established clinical guidelines that mandate contiguous levels only for cervical arthroplasty. 1

Critical Contraindications Present

Non-Contiguous Level Violation

• All FDA-approved cervical total disc replacement devices are indicated exclusively for contiguous levels between C3-C7 1
• The C3-4 and C5-6 levels are separated by the intervening C4-5 disc space, making this a non-contiguous configuration 2
• Multilevel cervical arthroplasty studies specifically define their populations as receiving "contiguous" implants at adjacent levels (e.g., C5-6 and C6-7, or C3-4 and C4-5) 2
• Hybrid constructs (TDR-ACDF-TDR) exist for non-contiguous disease, but pure arthroplasty at non-contiguous levels lacks FDA approval and safety data 2, 3

Unaddressed Osteoporosis Risk

• This 51-year-old female with history of gastric sleeve surgery represents high risk for osteoporosis and has never been tested 4
• Gastric sleeve surgery significantly impairs calcium and vitamin D absorption, necessitating supplementation (which she is taking) 4
• The MCG criteria explicitly require "no osteoporosis" as an absolute contraindication, yet bone density has never been assessed 4
• Cervical arthroplasty requires adequate bone quality for endplate fixation; osteoporotic bone increases risk of subsidence and implant failure 5

Cervical Instability Concerns

• The patient has documented retrolisthesis at both proposed surgical levels: 2mm at C3-4 and trace at C5-6 4
• MCG criteria require "absence of sagittal plane translation of more than 3mm on lateral flexion-extension x-rays" 4
• While the measured retrolisthesis is below 3mm threshold, flexion-extension radiographs are mandatory to definitively rule out dynamic instability before arthroplasty 4
• Static MRI cannot adequately assess segmental instability 4

Appropriate Alternative: Anterior Cervical Decompression and Fusion

ACDF Meets All Clinical Indications

• The patient has appropriate clinical presentation: 6 years of progressive neck pain, bilateral shoulder pain, right arm tingling, and objective 4/5 weakness in left deltoids and triceps 4
• MRI demonstrates large disc herniations at both C3-4 and C5-6 causing spinal cord flattening, which correlates with her myeloradiculopathy symptoms 4
• She has failed adequate conservative management: >6 weeks physical therapy, multiple cervical injections with diminishing efficacy, acetaminophen, heat, ice, massage, and chiropractic care 4
• ACDF provides 80-90% success rate for arm pain relief and 90.9% functional improvement in cervical radiculopathy with myelopathic features 4

ACDF at C3-4 and C5-6 is Guideline-Concordant

• Two-level ACDF at non-contiguous levels is an established, FDA-approved procedure with robust long-term outcome data 4
• The American Association of Neurological Surgeons recommends ACDF for patients with progressive cervical radiculopathy with myelopathic features (spinal cord flattening on MRI) refractory to conservative management 4
• Anterior cervical plating for 2-level disease reduces pseudarthrosis risk from 4.8% to 0.7% and improves fusion rates from 72% to 91% 4
• ACDF provides more rapid relief (within 3-4 months) of arm/neck pain, weakness, and sensory loss compared to continued conservative treatment 4

Addressing the C4-5 Level

• The imaging shows "still mobility at C3-4 level and a little bit of mobility at C5-6 level" but no mention of C4-5 pathology 4
• X-rays demonstrate "disc degeneration without any stenosis at the C6-7 level" but C4-5 is not described as pathologic 4
• If C4-5 is truly normal, a hybrid construct (ACDF at C3-4, skip C4-5, ACDF at C5-6) would be the appropriate surgical approach 2, 3
• If C4-5 has any degree of degeneration, three-level contiguous ACDF (C3-4, C4-5, C5-6) would be preferable to avoid adjacent segment disease at an intervening mobile segment 4

Common Pitfalls to Avoid

• Do not proceed with arthroplasty without bone density assessment in high-risk patients (postmenopausal age, gastric sleeve, vitamin D supplementation needs) 4, 5
• Do not rely on static imaging alone to assess stability; flexion-extension radiographs are mandatory before arthroplasty 4
• Do not attempt to use arthroplasty devices outside their FDA-approved indications (non-contiguous levels, >2 levels) as this exposes the patient to unproven risk and creates medicolegal liability 1
• Do not ignore documented retrolisthesis, even if below 3mm threshold, without dynamic imaging to assess for instability 4

Recommended Clinical Pathway

1. Obtain DEXA scan to assess bone mineral density given gastric sleeve history and age 4
2. Obtain flexion-extension cervical radiographs to definitively assess stability at C3-4 and C5-6 4
3. Proceed with two-level ACDF with anterior cervical plating at C3-4 and C5-6 (or three-level if C4-5 is also pathologic) 4
4. Consider hybrid construct only if C4-5 is definitively normal on all imaging modalities 2, 3