Incidence, Risk Factors, and Results of Nerve Pain After Surgery
Surgeons say numbness of the front and side of the thigh is common after spine surgery. The patient is placed face down over a special frame called the Relton-Hall frame. Pressure from the supports on a nerve close to the surface causes the problem. Just how often does this happen?

In this study about one-fourth of the patients had impaired sensation after spine surgery using this type of frame. About half of those patients had numbness on both sides. The condition is called meralgia paresthetica (MP).

Looking at all the data collected, these researchers concluded that there are three main risk factors for this problem. First, overweight and obese patients are at increased risk. While the patient is supported by the frame the large abdomen hangs down. This position with the suspended weight puts pressure on the nerve.

Second, a longer surgery time is a risk factor. Surgery lasting 3.7 hours (instead of the usual 3.2 hours) increases the risk of MP. Finally, a third risk factor was diagnosis. Most cases of MP occurred in patients operated on for degenerative spine conditions.

Although MP is common after some spine surgeries, the condition is temporary. The authors report everyone had returned to normal within two months. Many patients had complete recovery in the first week.
References
Shu-Hang, MD, et al. Postoperative Meralgia Paresthetica After Posterior Spine Surgery. In Spine. September 15, 2005. Vol. 30. No. 18. Pp. E547-E550.