Diskectomies occurred in approximately 370,000 inpatients, with slightly more females than males undergoing the procedure. This number is likely misleading because many diskectomies now occur in an outpatient setting. Of those undergoing the procedures, 42% had a diagnosis of either lumbar or cervical disc displacement, with more than 12% having a diagnosis of disk degeneration. (Reference Table 2.18 PDF CSV)

The largest number of patients with a diskectomy procedure (almost 50%) was in the 45- to 64-year age group. Patients spent on average 4.6 days in the hospital, although the median is between one and two days. Diskectomy procedures conducted in outpatient clinics are not included as there is no good source for this data at this time. The mean charges for diskectomy procedures were $35,000, for a total of $13 million. The majority of patients with a disc displacement diagnosis are not hospitalized. The most frequent encounters are physician office visits. (Reference Table 2.17 PDF CSV) 
 
Table 2.19 (PDF CSV) shows the diskectomy procedure trend in the United States from 1996 to 2011. It may seem surprising that the number is fairly stable given the population increase and the change in aging of the population. This is a reflection of the fact that more and more of these procedures are done in the outpatient setting and therefore not captured by the inpatient National Hospital Discharge Survey.