Journal List > J Korean Soc Spine Surg > v.18(3) > 1075931

J Korean Soc Spine Surg. 2011 Sep;18(3):123-131. English.
Published online September 30, 2011.  https://doi.org/10.4184/jkss.2011.18.3.123
© Copyright 2011 Korean Society of Spine Surgery
Conservative Treatment of Lumbar Disc Herniation - A Prospective Study of Disc Herniation Encroaching More than One-third of Spinal Canal -
Byung-Joon Shin, M.D., Jae Chul Lee, M.D., Ho-Hyoung Lee, M.D. and Hae-Dong Jang, M.D.
Department of Orthopaedic Surgery, Soonchunhyang University College of Medicine, Seoul, Korea.

Corresponding author: Jae Chul Lee, M.D. Department of Orthopaedic Surgery, Soonchunhyang University College of Medicine, 657, Hannam-dong, Yongsan-gu, Seoul, Korea. TEL: 82-2-709-9808, FAX: 82-2-794-9414, Email: jlee@schmc.ac.kr
Received January 17, 2011; Revised July 21, 2011; Accepted July 21, 2011.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Abstract

Study Design

Prospective study.

Objectives

To investigate the clinical results of conservative treatment for mid-to-large lumbar disc herniation diagnosed via magnetic resonance imaging (MRI) and the factors influencing treatment.

Summary of Literature Review

There is limited information regarding the clinical results of conservative treatment for lumbar disc herniation. The recent studies using MRI have suggested favorable treatment results.

Materials and Methods

The study subjects were 39 cases of herniated disc patients with over a 1/3 spinal canal encroachment -- based on MRI -- that were followed up for at least 1 year. The average age was 42.6-years-old (range of 12-76 years-old), and the average follow-up period was 28 months. The neurological deficit and the visual analogue scale (VAS) of back pain and radiating pain at the time of initial diagnoses and final follow-ups were compared, and the clinical results were evaluated based Kim & Kim's criteria.

Results

Although 4 of the 39 patients needed to undergo surgery during the follow-up period, 33 of the remaining 35 patients showed satisfactory (excellent and good ratings) results: 27 excellent, 6 good, 2 fair, i.e., a 85% (33 out of 39) satisfactory results. Of the 14 cases that had neurological defect at the initial diagnosis, only 1 case needed surgery, thereby resulting in a 93% (13 out of 14) satisfactory result. There were no statistically significant correlations among the degree of spinal canal encroachment and other factors such as age, sex, herniation type, and neurological deficit at initial diagnosis, and the clinical results at the final follow-up, conversion to surgery during follow-up, and remaining pains.

Conclusions

The clinical results of conservative treatment in lumbar disc herniation were satisfactory even in cases of high degree of spinal canal encroachment. Therefore, conservative treatment of lumbar disc herniation should be considered first before resorting to surgical treatment.

Keywords: Lumbar Disc Herniation; Conservative Treatment; MRI; Spinal Canal Encroachment

INTRODUCTION

Lumbar disc herniation is a common disease in the spine area and it occurs in 1%-2% of the total population1) in the U.S. about 200,000 diskectomies are performed annually.2) Recently, as MRI is used widely in diagnosing disc herniation, a great number of patients are being diagnosed with lumbar disc herniation and they are being treated - other than the surgical methods using microscope, endoscope, and laser - with a variety of treatment methods and rehabilitations.

However, there is a considerable amount of controversy in regard to the pathophysiology and treatment guidelines for lumbar disc herniation. After the study by Hakelius et al.3) on the natural progress of patients with radiating pain, although many reports about the sound natural progress of herniated disc patients along with surgery and conservative treatment have been published, there have been significant disagreements regarding the results. This is believed to be attributable to the differences in diagnostic methods which, importantly, caused the study subject groups to be different. However, according to the existing studies on the diagnoses of disc herniation were based on various methods ranging from using the symptoms of radiating pain as basis to myelogram and computed tomography. Some studies have used MRI, and, particularly, a small number of studies have used MRI for confirmation of all their cases.

In addition, there is a pattern of more recommendation for surgery when MRI shows greater degrees of disc herniation; as such, this study attempted to investigate about the clinical results of conservative treatment and the factors that influence the results of patients who were clearly diagnosed with herniated discs with over 1/3 canal encroachment shown on MRI and corroborating clinical symptoms such as radiating pain.

RESEARCH SUBJECTS AND METHODS

1. Study Subjects

The study subjects were comprised of, among the patients who visited our hospital from April 2006 to March 2009, the cases with -- either 1) the first symptoms occurred within 6 weeks, or 2) symptoms were older than 6 weeks but symptoms showing improving trend -- of the patients diagnosed through MRI with disc herniation of more than 1/3 spinal canal encroachment and with radiating pain in the associated dermatome.

The cases where the muscle strength was below grade 2 and there were severe neurological deficits or progressing neurological deficit, cauda equina syndrome, symptoms occurred more than 6 weeks before but no sign of improvement were recommended for surgery and were excluded as study subjects. Also excluded were the patients, during this period, who had a previous history of discectomy in the same region, spinal stenosis, foraminal and extraforaminal types.

This was a prospective study using the 44 cases that met the above criteria. Conservative treatments included analgesics, anti-inflammatory drug therapy, and spinal rehabilitation education. Among the 44 patients, 39 patients who could be followed up for more than 1 year were studied; the average age was 42.6 years old (range of 12-76 years old), 25 male cases, 14 female cases, and the average follow-up period was 28 months.

2. Study Methods

1) Analysis of Clinical Factors and Results

At the time of the initial and final follow-up, the patients' back pain and radiating pain were recorded using VAS (Visual Analogue Scale), and Kim & Kim's criteria (Table 1) was used to evaluate the clinical results, and cases that required surgery were classified as "bad". In addition, the prognostic factors such as the patients' age, sex, herniated region, herniation type, neurological deficits at initial diagnosis, back pain and radiating pain were measured.


Table 1
Kim & Kim's criteria of clinical outcome
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2) Radiographic Analysis

The degree of spinal canal encroachment was measured in the most encroached region from the axial view of the MRI image by using digital measurement tools (Fig. 1). The degree of spinal canal encroachment was on the average 49.7% (range of 33.4%-78.6%). On the MRIs, the types of herniation were classified into these categories according to the criteria of Costello et al.; protruded, extruded, and sequestrated.4) In this study, since only the degrees of herniation of 1/3 or more were used as study subjects, the protruded types were excluded.


Fig. 1
Spinal canal area and herniated disc size were measured on MRI axial images.
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3) Statistical Analysis

Statistically in the univariate analysis t-tests and cross analysis were used to determine the correlation between the clinical result scores at the time of the final follow-up and other factors that were expressed as non-continuous variables; Pearson correlation was used to determine the correlation between the clinical result scores at the time of the final follow-up and other factors that were expressed as continuous variables. Statistical test defined as significant when p <0.05.

RESULTS

1. Radiographic Analysis of the Results

The occurrence region was most frequent at Lumbar 4-5 (L4-L5) with 19 cases, next was Lumbar 5 - Sacral 1 (L5-S1) with 17 cases, next Lumbar 3-4 (L3-L4) with 2 cases, and then Lumbar 1-2 (L1-L2) with 1 case. Extruded type was in 35 cases, sequestrated type was in 4 cases; the highest degree of spinal canal encroachment measured from the axial view of the MRI image was on 49.7% (range of 33.4%-78.6%)(Table 2).


Table 2
Summary of cases
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2. Pain and Clinical Results

Of the 39 cases, 4 cases had to be converted to surgery due to the failure of conservative treatment or recurrence during the follow-up period; the remaining 35 cases showed VAS at the time of initial diagnosis of on average 2.3 (0-8) and at the time of final follow-up 0.5 (0-6), VAS for radiating pain was on average 5.5 (3-10) and at the time of final follow-up 0.4 (0-7). (Fig. 2) The clinical results were, of the 35 cases that did not require surgery: 27 cases of "excellent", 6 cases of "good", 2 cases of "fair" at the time of the final follow-up; i.e., without surgery 85% (33 out of 39) of all the cases showed satisfactory results(Fig. 3).


Fig. 2
VAS score at initial visit and the final follow-up
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Fig. 3
Clinical outcome at the final follow-up (four patients who converted to surgery were defined as "poor")
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3. Analysis of Cases Requiring Surgery During Follow-Up Period

Surgeries for the 4 cases that required conversion to surgery were performed after 2, 8, 19, and 24 months after the initial diagnosis; the Case #24 was showing improvement but took a turn for the worse of radiating pain about 2 months after the initial diagnosis, thereby resorting to surgery. Case #34 was improving but developed back pain and radiating pain around 8 months after the initial diagnosis, thereby resorting to surgery, which showed severe adhesion of the herniated disc and nerve roots during intraoperative observations. In the Cases #11 and #17, the symptoms disappeared with conservative treatment but they reoccurred: the Case #11 developed back pain and ipsilateral radiating pain after 19 months from the first visit, thereby resorted to surgery at another hospital; the symptoms in Case #17 completely disappeared after 2 months but they recurred and cauda equina syndrome complicated after 24 months, thereby requiring surgery.

The 3 cases that underwent surgery showed "excellent" clinical results at the final follow-up; the Case #17 that had cauda equina syndrome took over 1 year to regain urination and stool faculties.

4. Analysis of the Group with Neurological Deficits at the Initial Diagnosis

14 of the 39 cases showed neurological deficit such as muscle weakness: 1 case showed weakness in great toe extension down to Grade 3; the remaining 13 cases showed muscle weakness down to Grade 4. Although in the final follow-up every case showed improvement in the neurological deficit, 3 cases showed mild paresthesias and mild muscle weaknesses remained. At the final follow-up, the back pain and radiating pain score was, respectively, 0.14 and 0.21, which were less than those (0.60 and 0.48) of the group without any neurological deficit; however, there was no statistical significance (p = 0.158, 0.516).

1 of the 14 cases required surgery due to recurrence during the follow-up period; there were 12 cases of "excellent", and 1 case of "good", which indicated a 93% (13 out of 14) satisfactory clinical result, which was higher than that of the group without neurological deficit, but there was no statistical significance (p = 0.391).

5. Analysis of the Group with Over 50% Spinal Canal Encroachment

16 of the 39 cases showed 50%-plus spinal canal encroachments, and the average degree of encroachment was 61.4%. There were 11 male cases and 5 female cases; the average age was 40.9 years old which was slightly younger than that (42.8 years old) of the total case population. The occurrence regions were: 8 cases at Lumbar 4-5 (L4-L5), 7 cases at Lumbar 5 - Sacral 1 (L5-S1), and 1 case at Lumbar 3-4 (L3-L4); extruded type was in 15 cases, sequestrated type was in 1 case. At the time of the initial diagnosis, back pain score was on average 2.9 (0-8); radiating pain on average was 5.5 (3-10); at the final follow-up the average back pain score was improved to 0.3 (0-6) and the average radiating pain was improved to 0.5 (0-7). 2 of the 16 cases required surgery during the follow-up period due to reoccurrence of symptoms. The clinical results at the final follow-up were: "excellent" 12 cases, "good" 1 case, and "fair" 1 case, which indicated satisfactory results -- without surgery -- in 81% (13 out of 16) of the cases, which was a bit lower than that (87%, 20 out of 23) of the group with less than 50% encroachment, but there was no statistical significance (p = 0.674) (Fig.4).


Fig. 4
Thirty five year old male patient suffering from bilateral buttock and right leg pain showed canal encroachment about 53% on MRI axial image at the first visit(A). After conservative treatment for 17 months, pain subsided and herniated disc material was absorbed at the final follow up(B).
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6. Relationship Between Miscellaneous Factors at the Initial Diagnosis and Clinical Results

1) Age

The older age group (older than the average age of 42.6 years old), at the final follow-up, back pain and radiating pain scores were, respectively, 0.67 and 0.56, which were somewhat higher than those (0.24 and 0.24) of the not-old-age group, but they were not statistically significant. (p = 0.293, 0.421) The clinical results of the older age group was 83% (15 out of 18) satisfactory, which was similar to the 86% (18 out of 21) of the not-old-age group, thereby not showing any significant difference. (p = 0.837) The cases that required surgery during the follow-up period was 6% (1 out of 18), which was lower than that (14%, 3 out of 21) of the not-old-age group, but there was no statistical significance. (p = 0.370)

2) Gender

At the final follow-up, the back pain scores were on average 0.52 for males and 0.29 for females, and the radiating pain scores were on average 0.20 for males and 0.71 for females, which had no statistically significant difference (p = 0.562, 0.337).

The clinical results for males was 88% (22 out of 25) satisfactory (excellent and good), which was higher than that (79%, 11 out of 14) of the females, however, there was no statistical significance. (P = 0.647) Surgery was required in 8% (2 out of 25) of males and 14% (2/14) of females, but there was no statistically significant difference (p = 0.609).

3) Herniation Types

At the final follow-up, the back pain score for extruded type was on average 0.43 and sequestrated type was 0.50; the radiating pain score for extruded type was on average 0.43 and sequestrated type was 0.0, but there was no statistical difference (p = 0.911, 0.508). The clinical results for extruded type was 83% (29 out of 35) satisfactory, which was lower than the 100% (4 out of 4) for sequestrated type, but without statistical significance (p = 0.368). 11% (4 out of 35) of the extruded type required surgery, which was higher than that (0%, 0 out of 4) of sequestrated type, but without statistical significance (p = 0.475).

DISCUSSION

Hakelius,3) in his report on conservative treatment of patients with sciatica, reported that bed rest and the use of a corset resulted in a 93% improvement rate in 6 months, whereby a sound natural progress was suggested; however, since the report was published, controversies have continued to this day about the treatment results and natural progress of lumbar disc herniation. Although in this study only the cases with spinal canal encroachments of 1/3 or more based on MRI were used, during the 28-month follow-up period only 4 cases of the total 39 cases required surgery, and in most of the patients sound clinical results were observed. Without aggressive interventional procedures such as nerve block, 85% (33 out of 39) showed satisfactory results with conservative treatment alone, thereby demonstrating a good natural progress of disc herniation. This report was similar to the report by Saal et al.5, 6) in which 90% achieved satisfactory clinical results with aggressive rehabilitation efforts during a 31-month follow-up period. However, the results of this study is quite different from the results from the report by Weber et al.7) which stated that 17 cases (26%) of 66 conservative treatment cases required surgery within 1 year and the report by Atlas et al.8-10) which stated that 46% of group that underwent conservative treatment showed satisfactory results after 5-years. This could be attributable, as pointed out by Alaranta et al.11, 12) to the inaccuracy in diagnostic methods e. g. , myelogram in the study by Weber et al.7) The diagnostic methods used in study by Atlas et al.8-10) as well included myelogram, CT scan, MRI, etc. and they were different and not standardized; 20% of the group that received conservative treatment were diagnosed only by physical examination, which in turn rendered the study somewhat limited. In contrast, this study, by using MRI as the only diagnosis method, should be considered as having sufficient clinical value.

As MRI is being used for measuring the location, type and size of herniated discs, a number of studies are being undertaken, and this study attempted to assess the differences in the clinical results by measuring the degrees of spinal canal encroachments and types. Masui et al. stated that there was no association between the degree of spinal canal encroachment and clinical results, after following up on 21 cases for 7 years; there was no association found in this study either. However, Carlisle et al.14) reported in their retrospective study, which compared 44 cases that had undergone surgery and 44 cases that had undergone conservative treatment without surgery, that those patients who underwent surgery after the conservative treatment failed showed significantly large degree of spinal canal encroachment. As a reason for the conflicting results, Carlisle et al.14) proposed a possibility of the degree of spinal canal encroachment's affecting the decision to proceed with surgery. However, in the case of this study, although using only the cases with relatively large degrees of encroachments with more than 1/3 encroachment, it was possible to ascertain sound clinical results regardless of the degree of spinal canal encroachment.

In this study, even in the cases with more than 50% spinal canal encroachments, 81% (13 out of 16) achieved satisfactory clinical results, which weren't significantly different from those (87% satisfactory results) of the cases with 33%-50% spinal canal encroachments. These results are similar to the recent studies done using MRI; Cribb et al.15) reported that, by following up on 15 cases with more than 50% spinal canal encroachments for 24 months, in 14 of the 15 cases, improvement of clinical symptoms was shown without surgery, and reported that on average 80% reduction in size was shown, hence suggested that a careful consideration needs to be given regarding surgery due to potential surgical complications. In addition, Benson et al.16) by following up on 37 cases with more than 50% spinal canal encroachments for 23 months, reported that 83% satisfactory results were obtained, while only 4 cases required surgery. As such, regardless of the size of herniated discs, whether to undergo a surgery needs to be decided upon consideration of the duration and progress of the symptoms, and conservative treatment needs to be undertaken first before surgery.

The fact that sound natural progress was seen even in cases where herniation was accompanied by non-progressive neurological deficits regardless of treatment has been reported in numerous studies4, 5, 7, 10, 17, 18) in this study as well, it was seen that 14 cases with neurological deficits at the initial diagnosis showed improvement of the neurological deficits at the final follow-up, and in 3 cases only mild residual muscle weakness of Grade 4 was shown and resulted in a good progress. In addition, with the final clinical results showing a 93% (13 out of 14 cases) satisfactory result, it was suggested that, even in cases with neurological deficits at the initial diagnosis, as long as they are not of worsening pattern, conservative treatment should take precedence.

In this study, the factors at the initial diagnosis such as age, sex, and herniation type did not have an effect on the clinical results of conservative treatment. However, Takada et al.19) in their follow-up study of herniated discs using MRI, stated that the protruded type resulted in slower reduction in the size; since midsize-plus herniation only were used in this study, the protruded type disc herniation that were smaller than 1/3 spinal canal encroachment were excluded and only the extruded and sequestrated types were included. As such, in the future, additional studies are needed to investigate the differences in the results of conservative treatment among the protruded, extruded and sequestrated types. Many of the patients included in the study had been recommended for surgery by other hospitals, but using only conservative treatment they showed satisfactory clinical results. In addition, during the final interviews the patient satisfaction levels were high, and there were no cases of complications during the conservative treatment. Thus, even if the size of herniated disc is large in lumbar disc herniation cases and there are neurological deficits such as muscle weakness, as long as the symptoms are not too old and don't show worsening pattern, conservative treatment should be considered first. The disadvantages of this study were that investigation from the initial diagnosis-to-improvement in symptoms was not done due to the follow-up period not being continued and only the final follow-up results were analyzed, which rendered this study somewhat limited; because of any additional MRIs not taken during the follow-up period, the extent of resorption of the disc was not ascertained. Recently, the reports that verified sequentially the extent of the nerve root compression and resorption of the herniated disc using MRI are being published20, 21) at the current time where MRI has become mainstream for diagnosing lumbar disc herniation, if extensive, large-scale studies about the opinions of MRI, the natural progress and conservative treatment of lumbar disc herniation can be undertaken, they will become a great help in determining treatment guidelines.

CONCLUSION

In moderate to large size lumbar disc herniation cases, conservative treatment has resulted in most patients showing satisfactory results. Thus, when determining treatment methods, rather than surgery, conservative methods should be considered first, even if the herniated disc is large in size and there are neurological deficit. In addition, further studies, based on MRI findings, on the natural progress of lumbar disc herniation are deemed necessary.

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