THE AUTOMATED PERCUTANEOUS LUMBAR DISCECTOMY OF THE HERNIATED LUMBAR DISC
Dr. Horacio J. Serra
Introduction
Between April 1992 and March 1997 a descriptive, retro and prospective study was carried out on 305 patients operated of a lumbar disc hernia through the Automated Percutaneous Lumbar Discectomy (APLD).
Data was taken from the clinical records of these patients as well as pre and post surgical personal interviews. There were 196 male patients and 109 female patients. Prevailing were those between 32 and 45 years of age (36.6%). Of the 326 spaces operated on (21 patients with two spaces), the number of hernias was important in the level L4/L5 (59.4%). A post surgical follow-up during which pain was evaluated as a fundamental symptom, showed that 210 patients (69%) obtained an immediate and persistent relief. In the course of the following 3 months a total recovery of the symptoms was obtained in 272 patients (89%). In these cases the lumbar paravertebral contracture was the most outstanding complication. Only three patients presented recurrent symptoms within the year of their operation. The remaining 10% obtained a high degree of relief from the radicular pain after the technique was applied. The time it took the patient to be reinserted at work and in his social life was an average of only 15 days.
The lumbar disc hernia is as old as humanity itself. It has been described since the remote times when man started to adopt a biped position and support all his weight on his spinal column.
In 1934 Mixter described this pathology for the first time, but its surgical treatment was not made known until the 50´s. The manual percutaneous discectomy was performed for the first time by Hijikata in 1975. Since then, the techniques and the instruments used to perform this operation have been modified with the intention of improving its results. The technique used in the AUTOMATED PERCUTANEOUS LUMBAR DISCECTOMY was developed by Dr. Gary Onik, of the University of Pittsburgh, in 1984. It allows the aspiration of the herniated nucleus pulposus under local anesthesia, with almost no bloodshed, and without injuring any important structures that maintain the stability of the spinal column. It requires but a couple of hours of confinement and it allows fast rehabilitation. Notwithstanding, its use is restricted to specific characteristics of the patient and the disc. This is an alternative therapy which should be born in mind because of its practicality, minimal aggression and because of its outstanding results within a limited indication.
Material and Method
Between April 1992 and March 1997, as the 305 patients were being treated, the standardized evaluation data, which was recollected from before and after the operation, were kept in data collection files.
Of the 305 patients (196 males and 109 females) 181 presented a 4th space hernia, 103 hernia of 5th space and 21 patients presented double hernias of 4th and 5th space, thus a total of 326 APLDs were conducted. The rigid 2mm Nucleotome was used through out all of these surgeries. The average age was of 43.6 years, with a range between 20 and 63 years of age.
In all the cases the patients under went surgery with local anesthesia and intravenous neuroleptoanesthesia support with 100% oxygen administered through nasal tubes, in lateral position of the side of the hernia. We understand that in this way, contrary to the original technique, i.e. by resorting to a contralateral approach to the side of the hernia it is easier to reach its neck with the rigid 2mm nucleotome.
The confinement of the patient extends during 4 to 6 hours and exercises are indicated to elongate the spine muscles on the same day. Customarily and depending on the activity the patient resumes working a week from having been intervened.
The diagnosis was based upon the clinical data obtained from consultations and through image studies (simple x-rays, CAT scans and MRI’s) and by a follow up of not more than 58 months and no less than 6. The patients were selected by means of inclusion and exclusion criteria.
Inclusion Criteria
Clinical
Up to 65 years old. Lumbar pain with sciatic or crural irradiation. The patient’s motor strength should not have diminished. Sensibility disorder in the specific neural segment. Previous treatment of 6 to 8 weeks.
X-rays findings
Normal intervertebral height. Absence of arthrosis signs. Typical changes of the lumbosacra transition vertebrae.
CAT Scan
Correlative data to the clinical discoveries. Lumbar spaces of L1 to S1. Any localization within the space. Disc protrusion that does not surpass the limits of the articular joint.
MRI
A hernia not superior to 50% of the rachidian canal in the sagital view. Without a disruption of the fibrous ring. T2 opacity.
Exclusion Criteria
Clinical
Age over 65 years. Reduced muscular strength. Positive contralateral Lasegue test. Cauda Equina Syndrome. Antecedents of open surgical procedures at the same level.
X-rays
Intervertabral space reduced. Fascetic Arthrosis . Disc calcification.
Results
The results obtained may show a higher success percentage when compared to the majority of the authors. We believe that this is due to the correct selection of patients.
Of the 305 patients, following the referred criteria upon evaluating pain, medication, Lasegue test, sensibility and occupation, we observe a 69% excellent results, 18% very good results, 2% good results, 8% satisfactory results, 2% fairly good results and 1% bad result one year after the surgery.
In other words 272 (89%) surgeries prove to be successful where as in 33 (11%) surgeries the results that were expected were not obtained. The results also show a variation of success according to the space treated. When the L4/S1 level were operated on, the percentage of success rose to 93%, while in the cases of L5/S1 the percentage descended to 73%.
Discussion
The APLD is proposed as a therapeutic option for a large percentage of lumbar disc hernias. We believe that out of all the patients who see their doctor about a hernia 65 to 70% can be operated through this method.
Conventional surgery uses general anesthesia, produces a great loss of blood and the execution of resections of structures and elements which may result important in maintaining future stability of the spinal column.
With the APLD we have not observed a decrease in the height of the invertebrate space, as it can be observed in other conventional surgical methods. We should bear this in mind knowing that the decrease in space is considered by some authors as the previous step to spinal column instability.
The fact that the procedure is conducted under local anesthesia reduces the risks of neurological lesion since it is already very difficult to cause a reticular damage in a patient who is conscious. According to our experience no lesion of this sort has occurred.
The use of the Nucleotome by the shape of its tip also decreases the risk of damage to vascular structures, nerves or of other noble elements. Putting it into operation once it has gone beyond the fibrous annulus, avoids all possible lesion to the neighboring structures.
In the three patients that were operated on by the open surgery method, the APLD previously performed did not interfere neither with the surgical labor nor with the post evolution.
An important advantage of this method is that it avoids epidural bleeding and the perineural fibrosis that in general are a cause of relapse of the symptomatology. In addition, you can avoid new hernias that usually form themselves through the window of the fibrous ring in conventional surgery.
From the aesthetic point of view it is important to take into account that there is practically no post surgical scar left and that the one that remains after a conventional surgery can affect in social life or at the time of qualifying any patient's working capacity.
Conclusions
We can consider this procedure as a choice for some disc hernias. As in any other pathology, if you want to achieve a therapeutic success, the first step is adequate diagnosis, in this particular case it acquires even a higher degree of importance.
You must also bear in mind that as time passes and the quality of the diagnosis methods improve, the surgical method becomes more precise and we try to use the method that is most efficient, less bloody, less aggressive and effective for radicular decompression.
We believe that the most advanced models of nucleotomes open a range of hernias that can be operated on and decreases the possibility of not being able to operate the radicular compression caused by extruded disks.
The good and precise choice of a surgical procedure, avoid complications that oblige the patients to undergo a second or even more operations, with the consequent harms this would cause them.