Objective: To determine the long-term follow-up of the various operations for lumbar disc herniation in a large patient population. Subjects and Methods: Patients who had operations for lumbar disc herniation (microdiscectomy, endoscopic microdiscectomy and the ‘classical operation', i.e. laminectomy/laminotomy with discectomy) were collected from the world literature. Patients who had follow-ups for at least 2 years were analyzed relative to the outcome. The outcome was graded by the patients themselves, and the operative groups were compared to one another. Results: 39,048 patients collected from the world literature had had lumbar disc operations for disc herniations. The mean follow-up period was 6.1 years, and 30,809 (78.9%) patients reported good/excellent results. Microdiscectomy was performed on 3,400 (8.7%) patients. The mean follow-up was 4.1 years with 2,866 (84.3%) good/excellent results, while 1,101 (3.6%) patients had endoscopic microdiscectomy. There, the mean follow-up was 2.9 years with 845 (79.5%) good/excellent results. The classical operation was performed on 34,547 (88.5%) patients with a mean follow-up period of 6.3 years, and 27,050 (78.3%) patients had good/excellent results. These results mirror those with discectomy and the placement of prosthetic discs. Conclusions: The analysis of 39,048 patients with various operations for lumbar disc herniation revealed the same pattern of long-term results. Patients who had microdiscectomy, endoscopic microdiscectomy or the classical operation (laminectomy/laminotomy with discectomy) all had approximately 79% good/excellent results. None of the operative procedures gave a different outcome.
Operations for lumbar disc herniation are numerous [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56] and have been performed since the 1934 publi- cation by Mixter and Barr . Indeed, operations for lumbar disc herniation are the most frequently done neurosurgical procedures. However, unlike the long-term success rate of posterior operations for cervical disc herniation, which is 94%, the overall long-term success rate for operations for lumbar disc herniations is considerably lower. For this reason, various operations were done with the hope that the long-term success rate would improve.
Since the ‘classical operation' (laminectomy/laminotomy with discectomy), other approaches have been used. Of these, the most popular are 2 operative procedures: (a) microdiscectomy and (b) endoscopic microdiscectomy. The average size of the published series of operations (classical, microdiscectomy and endoscopic microdiscectomy) is only several hundred patients/series, and most series did not attempt assessing the long-term outcome. The purpose of the present study was to analyze the long-term outcome of operations for lumbar disc herniation and then, specifically, the outcomes for each of the following: microdiscectomy, endoscopic microdiscectomy and the classical operation. To nullify the occasional unusual result, the goal of the study was to analyze the largest number of such patients published to date.
Subjects and Methods
All patients operated on for lumbar disc herniation with radiculopathy and followed for a minimum of 2 years postoperatively were collected from the world literature (using references cited in published studies, the studies themselves and the website PubMed, the search was complete). Good/excellent outcome was measured by the patients' own analyses because the best outcome measure is most simply what the patient thinks about the outcome [19,24]. Hobbs et al.  noted that the patient's perception was the ‘true measure of success'. Then, the operations with good/excellent outcomes were tabulated. The patients were divided into groups by the type of operative procedure, i.e. microdiscectomy, endoscopic microdiscectomy and the classical operation, and were analyzed by the time of follow-up and by which patients had good/excellent results by the patients' own assessment.
Thirty-nine thousand forty-eight patients collected from the world literature had had operations for lateral lumbar disc herniation with radiating pain and met the follow-up requirement of at least 2 years. Of the 39,048 operations, 95% of lumbar disc herniations were at the lowest 2 levels of the lumbar spine, and 49 and 46% were at L4-5 and L5-S1, respectively. Of the remaining 5% lumbar disc herniations, 0.15% were at L1-2, 0.65% were at L2-3 and 4.2% were at L3-4 (table 1). The mean follow-up period in this series was 6.1 years. Of all the patients, 30,809 (78.9%) had good/excellent outcomes (table 2). Microscopic discectomy was performed on 3,400 (18.7%) patients with a mean follow-up of 4.1 years. Good/excellent results occurred in 32,917 (84.3%) patients (table 3). The endoscopic microdiscectomy group consisted of 1,101 (3.6%) patients with a mean follow-up period of 2.9 years, and 845 (79.5%) patients had good/excellent results (table 4). Of the 39,048 patients, 34,547 (88.5%) had the classical operation (laminectomy/laminotomy with discectomy). The mean follow-up was 6.3 years. The patients had 78.3% good/excellent results (table 5).
In the 8 decades since the publication by Mixter and Barr , many studies of the surgical management of lumbar disc herniation with radiculopathy have been published showing the results of laminectomy/laminotomy with discectomy. Another operative approach was described over 4 decades later, i.e. microdiscectomy [7,52,55]. Later still, another surgical approach to lumbar disc herniation was developed with the advent of endoscopic microdiscectomy . Many series were published about the above 3 surgical techniques. Significantly fewer publications dealt with the long-term results of these different operative approaches.
In studies focused on the long-term results of the surgical management of lumbar disc herniation, most series that were published averaged several hundred patients. In the 45 studies analyzed here, the mean number of patients was 382/series. This study analyzes 39,048 patients operated for lumbar disc herniation with radiculopathy and followed for over 6 years.
Approximately 79% of the outcomes, graded by the patients, were good/excellent. A series of this size is not affected by slight variations in technique with various surgeons and by variations in the patients' ages and gender.
Each of the operations for this problem was an attempt to improve the outcome by using different operative approaches and techniques; however, as is shown in the present analysis, there is no real difference in the long-term outcome with the above operations. Good/excellent outcomes were 79% overall and 84% for microdiscectomy, 80% for endoscopic microdiscectomy and 78% for the classical operation (laminectomy/laminotomy and discectomy). Another attempt at improving the outcome was the use of the prosthetic disc; however, in long-term studies (46 patients at 3.2 years of follow-up; 105 patients at 4.3 years of follow-up), the good/excellent results were 77 and 79%, respectively [9,25]. All of the operations analyzed have good/excellent results of around 79%. Different approaches and different techniques do not appear to have made any real difference in the long-term outcome.
The results of posterior operations for lumbar disc herniation are not as good as the results of posterior operations for cervical disc herniation. An analysis of over 3,000 such posterior operations for cervical disc herniation with an 8.5-year mean follow-up revealed 94% good/excellent results . Why is there this difference of 79% versus 94%? Surely the operative procedures were successful in both groups, but much more so in the cervical spine. The reason for this difference needs further analysis and, perhaps, yet another approach, surgical or otherwise, to the problem of lumbar disc herniation with radiculopathy.
Each of the operations for lumbar disc herniation (microdiscectomy, endoscopic microdiscectomy and laminectomy/laminotomy with discectomy) had approximately 79% good-to-excellent results. There was no difference in the long-term follow-up in any of the operative groups, including the use of a lumbar disc prosthesis (‘artificial disc').