Orthopedic With Answers Review | Dr Hutaif General Orth -...

DISCUSSION: Anatomic studies have shown that the thickest bone of the occiput is at the level of the external occipital protuberance. It ranges from 11.5 mm to 15.1 mm in men and from 9.7 mm to 12 mm in women. In general, the bone thins as it extends distally from the external occipital protuberance and it also moves laterally from the midline. The structures at risk during screw placement include the venous sinuses.

Scientific References

: Nadim Y, Lu J, Sabry FF, et al: Occipital screws in occipitocervical fusion and their relation to the venous sinuses: An anatomic and radiographic study. Orthopedics 2000;23:717-719.
Ebraheim N, Lu J, Biyani A, et al: An anatomic study of the thickness of the occipital bone: Implications for occipitocervical instrumentation. Spine 1996;21:1725-1729.
**23**. A patient who underwent an L5-S1 diskectomy 18 months ago has persistent pain in the left leg. Figures 9a and 9b show postoperative axial T 1-weighted MRI scans at the L5-S1 level without and with gadolinium. What is the most likely diagnosis?

DISCUSSION: Four years after surgery, more than 90% of patients are satisfied with the cosmetic appearance of the iliac donor site scar. Approximately 25% still have pain and/or functional difficulty, including 12.7% who still report difficulty with ambulation, 11.9% difficulty with recreational activities, 7.5% with sexual intercourse, and 11.2% require pain medication for iliac donor site symptoms.
REFERENCES: Silber JS, Anderson DG, Daffner SD, et al: Donor site morbidity after anterior iliac crest bone harvest for single-level anterior cervical discectomy and fusion. Spine 2003;28:134-139.
Cockin J: Autologous bone-grafting complications at the donor site. J Bone Joint Surg Br 1971;49:153.
**84**. When treating osteoporosis with alendronate, what is the most common side effect?