Back Pain and Neurological Deficit

🗒️ Question

A 58 year old woman with known metastatic breast cancer presents to her oncologist with worsening lower back pain over the past month. She describes the pain as constant and dull, with occasional radiation to the left leg. She reports reduced mobility and mild urinary urgency, although she denies incontinence. She is currently on palliative endocrine therapy.

On examination, there is tenderness over the lumbar spine. Neurological examination reveals decreased power in the left lower limb (4/5) and reduced sensation over the L5 dermatome. Reflexes are normal, and there is no evidence of saddle anaesthesia.

Investigations

• Haemoglobin: 105 g/L (115–150)

• Calcium: 2.7 mmol/L (2.2–2.6)

• Alkaline phosphatase: 240 U/L (30–130)

What is the most appropriate investigation of choice?

(A) Bone scintigraphy

(B) Lumbar spine X-ray

(C) CT of the lumbar spine

(D) MRI of the spine

(E) PET-CT scan