Original Paper
Med Princ Pract 2021;30:244–252 Received: July 2, 2020
DOI: 10.1159/000515308 Accepted: January 20, 2021
Published online: February 18, 2021
Clinical and Radiological Follow-Up Results 
of Patients with Sequestered Lumbar Disc 
Herniation: A Prospective Cohort Study
Hamza Sucuoğlua, b     Abdullah Yüksel Baruta 
aSchool of Health Sciences, Istanbul Gelisim University, Istanbul, Turkey; bDepartment of Physical Medicine and 
Rehabilitation, Private Nisa Hospital, Istanbul, Turkey
Significance of the Study
• Spontaneous regression can be observed with conservative treatment in most patients with sequestered 
lumbar disc herniation (LDH).
• Although pain and disability scores were better in operated patients who underwent early surgery, they 
were similar to those in patients who regressed spontaneously at 6 months.
• We recommend conservative treatment in the early period in patients with sequestered LDH with no 
surgical indication.
Keywords ated group were divided into 3 groups: nonregression (n = 
Lumbar disc herniation · Magnetic resonance imaging · 6), partial regression (n = 22), and complete resolution (n = 
Neurology · Pain · Radiology · Rehabilitation · Sequestered 27); patients were analyzed in 4 groups including the ones in 
lumbar disc herniation · Spontaneous regression the operated (n = 25) group. Results: Significant improve-
ments were observed in VAS and ODI scores at V2 and V3 in 
all groups (p = 0.000) and at V4 in partial regression and com-
Abstract plete resolution groups (p = 0.000). VAS and ODI score im-
Purpose: The aim of the study was to assess radiological provements at V2 and V3 were significantly higher in the op-
changes and clinical outcomes of patients with sequestered erated group than in other groups (p = 0.000). At V4, there 
lumbar disc herniation (LDH) and evaluate the relationship were no significant differences in VAS and ODI scores (p > 
between them. Methods: Patients diagnosed with seques- 0.05) between the operated group and partial regression 
tered LDH were followed up in 2 groups: operated (within and complete resolution groups. Conclusion: Spontaneous 
the 1st month after diagnosis) and nonoperated. Visual ana- regression was observed in the 6th month post-MRI in most 
log scale (VAS) and Oswestry Disability Index (ODI) scores at of the nonoperated sequestered LDH patients with conser-
baseline (V1) and 1st (V2), 3rd (V3), and 6th (V4) month visits vative treatment. Improvements in pain and disability scores 
were used for clinical evaluation. Radiological evaluation were higher among the operated patients at the early stage, 
was performed by measuring the sequestered LDH level and whereas they were not significantly different compared to 
herniation volume using magnetic resonance imaging (MRI) patients with spontaneous regression at the 6th month.
at V1 and V4. After the second MRI, patients in the nonoper- © 2021 The Author(s)
Published by S. Karger AG, Basel
karger@karger.com © 2021 The Author(s) Correspondence to: 
www.karger.com/mpp Published by S. Karger AG, Basel Hamza Sucuoğlu, hamzasucuoglu @ gmail.com
This is an Open Access article licensed under the Creative Commons 
Attribution-NonCommercial-4.0 International License (CC BY-NC) 
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Introduction the rules of the Declaration of Helsinki, and all individuals gave 
written consent prior to participation.
Lumbar disc herniation (LDH) causes lower back pain Participants
and radicular pain and functional constraints, disrupting This study was conducted at the Physical Therapy and Reha-
the quality of life. LDH has 5 identified herniation sub- bilitation Clinic, Private Nisa Hospital, between October 2017 and 
types: bulging discs (mildest form), focal protrusions, April 2020. We included patients aged between 18 and 70 years 
broad-based protrusions, extrusions, and sequestrations who were admitted to the outpatient clinic with lower back pain 
(the most severe form) [1, 2]. The distinction between se- and a sequestered LDH in the lumbar MRI scan. The patients’ symptoms and physical examination findings were consistent with 
questered LDH and other hernia subtypes showing simi- sequestered LDH. Sequestered LDH was diagnosed by detecting at 
lar clinical findings can be demonstrated using magnetic least one plane herniated disc mass (fragment) separated from the 
resonance imaging (MRI) [3]. Sequestrations, also known disc. The exclusion criteria were as follows: pregnancy, spondylo-
as free fragments, are fragments of nucleus pulposus and listhesis, spinal stenosis, lower back pain combined with inflam-
annulus fibrosus separated from the intervertebral discs matory diseases, vertebral fracture, spine infection and tumors, cauda equina syndrome, and a history of lumbar surgery.
[2, 4]. Among the LDH subtypes, the prevalence of se- Some of the patients diagnosed with sequestered LDH under-
questrations is 1.7–3% [5, 6]; however, the prevalence of went surgery (within the 1st month after diagnosis), whereas most 
surgery is 7% [5]. The concern that neurological deficits of them did not. Approximately 50% of the patients who under-
may develop in patients with sequestered LDH may in- went surgery had muscle weakness, and some others had severe 
crease the rate of preference for surgical intervention [7]. pain. The patients were divided into 2 groups at the first stage: those who underwent surgery (operated) and those who did not 
However, spontaneous regression of LDH has long been (nonoperated). After the control MRI taken at the 6th month, non-
well known [8–10]. In general, larger herniations are operated patients were divided into 3 groups of nonregression, 
known to regress faster than smaller ones, and the great- partial regression, and complete resolution and the 4th group of 
est regression is observed in the sequestered subtype [9– operated patients (those who underwent surgery at the first stage; 
11]. Moreover, successful results can be achieved with Fig.  1). Nonoperated patients continued conservative treatment (e.g., analgesic or nonsteroidal anti-inflammatory drugs, myore-
conservative treatment in most cases of sequestered LDH laxant drugs, physical therapy, exercises, lumbosacral orthosis, 
without absolute indications for surgery [9–11]. Deter- rest, and epidural steroids). These treatments were continued for 
mining the relationship between spontaneous regression up to 2 months for some patients; most of the patients received 
and the improvement of clinical symptoms was done by multiple treatments.
following disc herniation and morphological changes in Evaluations
discs with serial MRI [3, 12]. During the initial examination of the patients, the following 
A few case reports and reviews have reported sponta- parameters were recorded: age, sex, BMI, duration and location of 
neous regression in sequestered LDH [9–11]. To the best pain, and muscle weakness. Clinical evaluation was conducted us-
of our knowledge, there is only one prospective cohort ing the visual analog scale (VAS) [14] and the Turkish-approved 
follow-up study [13]. Studies on clinical and radiological version of the Oswestry Disability Index (ODI) [15] via face-to-face interviews with the patients at baseline (V1) and 1st (V2), 3rd 
comparison of sequestered LDH patients who underwent (V3), and 6th (V4) month visits. The evaluator was an experienced, 
surgery with those who underwent conservative treat- independent physiatrist blinded to the radiological information. 
ment without surgery and their spontaneous regression MRIs taken at V1 and V4 were used for radiological evaluations.
images have not been reported. Thus, in this prospective Visual Analog ScaleThe VAS assessment, which was used in 
cohort study, we aimed to detect the clinical outcomes this study to measure the patients’ levels of pain, was made using figures from “0” to “10” marked equally in a 10-cm line. The au-
and radiological changes in MRI (regression, resolution, thors explained to the patients that “0” means no pain, “5” means 
or none) by performing a periodic follow-up of patients moderate pain, and “10” means unbearable pain; the patients were 
with operated and nonoperated sequestered LDH and to asked to mark the appropriate score on the line that best described 
determine the relationship between them. their pain [14].
ODI Score
The ODI is recognized as the “gold standard” of lumbar func-
Materials and Methods tional outcome instruments and focuses on physical activities. It 
consists of 10 physical activity sections rated from 0 to 5. The total 
Study Design score is calculated by adding up all the points marked in each sec-
We used a prospective cohort study design in accordance with tion. The total possible score is calculated by multiplying the num-
the STROBE statement. The study protocol was approved by the ber of marked episodes by 5, and the maximum possible score is 
Ethics Committee of Istanbul Gelisim University (Decision No. 50. The ODI total score (%) is calculated by dividing the total score 
19.04-20/05.08-17). The study was conducted in accordance with by the total possible score and multiplying the quotient by 100. 
Clinical and Radiological Results of Med Princ Pract 2021;30:244–252 245
Sequestered Lumbar Disc Herniation DOI: 10.1159/000515308
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Assessed for eligibility (n = 115)
Inclusion criteria:
Sequestered lumbar herniation in MRI Exclusion criteria (n = 17):
>18 to 70 years old Pregnancy, spondylolisthesis,
spinal stenosis, low back pain
combined with inflammatory
diseases, vertebral fracture,
spine infection and tumors,
cauda equina syndrome,
previous history of lumbar surgery
Baseline assessment_V1
(n = 98)
Operated (n = 32) Non-operated (n = 66)
n = 29 1st month_V2 (n = 89) n = 60
Lost to Lost to
follow-up n = 27 3rd month_V3 (n = 84) n = 57 follow-up
(n = 7) (n = 11)
Operated (n = 25) 6th month_V4 (n = 80) Non- Partial Complete
– Recurrence (n = 3) Control MRI regresssion regresssion resolution
– Complete resolution (n = 22) & (n = 6) (n = 22) (n = 27)Analyses
Fig. 1. Flow diagram of the study. MRI, magnetic resonance imaging.
High scores indicate that the individual is more affected by the as recurring pain in operated patients along with the observation 
disease [16]. of disc hernia at the same level in the control MRI.
Magnetic Resonance Imaging Statistical Analyses
All patients were imaged using a 1.5T MRI scanner (Signa All statistical analyses were performed using SPSS version 20.0 
HDxt 1.5T; GE Healthcare, USA) with the spine coil in a supine (IBM Corp., Armonk, NY, USA). Data were presented as mean ± 
position. Lumbar spinal MRI consisted of sagittal T1W, sagittal standard deviation (median [minimum-maximum]) for continu-
T2W, and axial T2W images. The same experienced radiologist ous variables, and as frequencies and percentages for categorical 
blinded to the clinical information evaluated MRI scans taken with variables. Normality of the data was assessed using the Shapiro-
the same device. The sequestered LDH level and sequestered her- Wilk test. The one-way ANOVA test was used for the intergroup 
nia (fragment) volume of the patients were determined. The hernia comparison of continuous variables with normal distribution. The 
volume (mm3) was calculated by measuring the area (mm2) in each Wilcoxon signed-rank test was used for the intragroup compari-
axial image and multiplying this value by the scanning thickness son of continuous variables without normal distribution; the Krus-
(4 mm) plus intraslice clearance (1 mm) [7]. The patients were di- kal-Wallis test was used for the cross-group comparison. When 
vided into 3 groups depending on the change in the volume of the statistically significant differences were found between the groups, 
sequestered disc hernia in the sagittal and axial views: (1) nonre- the Mann-Whitney U test was used to determine groups causing 
gression: no change in disk volume; (2) partial regression: >25% the difference. A χ2 test was used to compare the categorical vari-
herniation size reduction; and (3) complete resolution: herniated ables. For all analyses, the level of significance was set at p < 0.05.
disc volume is absent (Fig. 2). In addition, recurrence was defined 
246 Med Princ Pract 2021;30:244–252 Sucuoğlu/Barut
DOI: 10.1159/000515308
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a b
Fig. 2. View of caudal migrated sequestered 
disc hernia compressing the right lateral L5 
root at the L4–L5 level on sagittal (a) and 
axial (b) sections in the MRI performed at 
V1 (baseline). View of complete resolution 
at the L4–L5 level on sagittal (c) and axial 
(d) sections in the MRI performed at V4 
(follow-up). MRI, magnetic resonance im-
aging. c d
Results None of the nonoperated patients with continued V4 
underwent surgery; recurrence was observed in 3 (12%) 
A total of 115 sequestered LDH patients were evalu- of the operated patients. The duration from diagnosis to 
ated, and 98 patients were finally included in the study. surgery among operated patients [mean ± SD (median 
Of these patients, 32 (32.7%) underwent surgery (oper- [minimum-maximum])] was 10.8 ± 10.7 (7.0 [0–30]) 
ated), whereas 66 (67.3%) did not undergo surgery (non- days.
operated) and received conservative treatment. Follow- There was no significant difference in the VAS and 
ing the control MRI scan conducted in 80 patients with ODI scores between the groups at V1 (p = 0.710 and p = 
continuing follow-ups at V4, 6 (10.9%) patients were in- 0.954, respectively) (Fig. 3, 4). The nonregression group 
cluded in the nonregression, 22 (40%) in the partial re- had significantly higher VAS and ODI scores at V2, V3, 
gression, and 27 (49.1%) in the complete resolution and V4 than the other groups (p = 0.000) (Fig. 3, 4). Sig-
groups; 25 patients remained in the operated group. Sta- nificant improvements were observed in VAS scores at 
tistical analysis was conducted with the 80 patients in V2 and V3 in all groups (p = 0.000). Significant improve-
these 4 groups (Fig. 1). ments in the VAS scores within the groups were contin-
Table 1 shows the clinical and demographic character- ued in all follow-ups (V2, V3, and V4) in the partial re-
istics of the patients. There was no significant difference gression and complete resolution groups (p = 0.000). 
between the groups in terms of mean age and duration of However, VAS scores in the nonregression group and the 
pain (p > 0.05). The sequestered LDH level was most operated group did not show a significant difference at 
commonly L4-L5 (37.5%) and L5-S1 (37.5%), with no sig- V4 compared with V3 (p = 0.083 and p = 0.670, respec-
nificant difference between groups (p > 0.05). Muscle tively). The operated group had significantly lower VAS 
weakness was markedly more prevalent in the operated scores at V2 and V3 than the other groups (p = 0.000). At 
group at V1 (48%; p = 0.003). In addition, the improve- V4, the VAS scores in the operated group were no differ-
ment in muscle weakness was statistically significant in ent from those of partial regression and complete resolu-
the operated group (p = 0.001). tion groups (p = 0.812) (Fig. 3).
Clinical and Radiological Results of Med Princ Pract 2021;30:244–252 247
Sequestered Lumbar Disc Herniation DOI: 10.1159/000515308
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248 Med Princ Pract 2021;30:244–252 Sucuoğlu/Barut
DOI: 10.1159/000515308
Table 1. Demographic and clinical features of the patients
Variable Total Nonregression Partial regression Complete resolution Operated p value
(n = 80) (n = 6) (n = 22) (n = 27) (n = 25)
Age, years1 47.7±10.2 46.5±12.8 47.0±10.5 46.3±10.3 50.2±9.4 0.527a
(48.0 [25–67]) (49.0 [25–62]) (47.5 [27–66]) (45.0 [27–67]) (50.0 [35–67])
BMI 26.8±4.4 26.5±4.8 26.4±4.1 26.3±3.5 27.7±5.5 0.661a
(26.3 [18.9–42.1]) (25.1 [21.4–34.6]) (26.7 [18.9–35.3]) (25.9 [20.3–35.1]) (27.1 [19.2–42.1])
Sex, n (%)
Female 45 (56.3) 1 (16.7) 12 (54.5) 19 (70.4) 13 (52.0) 0.102c
Male 35 (43.7) 5 (83.3) 10 (45.5) 8 (29.6) 12 (48.0)
Duration of pain (days),1 n (%) 5.0±7.5 5.7±9.0 4.9±7.3 6.2±8.4 3.7±6.5 0.189b
(2.0 [1–30]) (2.0 [1–24]) (2.0 [1–24]) (2.0 [1–30]) (1.0 [1–30])
Location of pain, n (%)
Low back 4 (5.0) 1 (16.7) 2 (9.1) 1 (3.7) 0 (0.0) 0.390c
Low back and right leg 36 (45.0) 2 (33.3) 7 (31.8) 15 (55.6) 12 (48.0)
Low back and left leg 40 (50.0) 3 (50.0) 13 (59.1) 11 (40.7) 13 (52.0)
Muscle weakness, n (%)
Baseline (V1) 18 (22.5) 0 (0.0) 3 (13.6) 3 (11.1) 12 (48.0) 0.003c
Follow-up (V4) 12 (15.0) 1 (16.7) 2 (9.1) 2 (7.4) 7 (28.0) 0.161c
Level of sequestered LDH, n (%)
L1–L2 3 (3.8) 1 (16.7) 0 (0.0) 1 (3.8) 1 (4.0) 0.767c
L2–L3 6 (7.4) 1 (16.7) 1 (4.5) 3 (11.1) 1 (4.0)
L3–L4 11 (13.8) 0 (0.0) 5 (22.8) 3 (11.1) 3 (12.0)
L4–L5 30 (37.5) 2 (33.3) 7 (31.8) 10 (37.0) 11 (44.0)
L5–S1 30 (37.5) 2 (33.3) 9 (40.9) 10 (37.0) 9 (36.0)
Volume of herniation (mm3)1
Baseline (V1) 1,441.0±682.5 1,476.0±884.7 1,524.2±558.5 1,245.6±738.2 1,521.2±548.8 0.245a
(1,321.7 [772.5–1,617.3]) (1,380.2 [764.0–2,018.2]) (1,411.3 [874.1–2,132.0]) (1,114.2 [684.0–1,997.5]) (1,382.3 [768.3–2,241.0])
Follow-up (V4) 1,069.0±599.6 1,396.0±847.6 742.5±351.6 
(896.3 [528.5–1,499.6]) (1,340.0 [812.0–1,988.8]) (452.2 [245.6–1,011.8])
LDH, lumbar disc herniation. 1 Mean ± standard deviation (median [minimum-maximum]). a One-way ANOVA. b Kruskal-Wallis test. c χ2 test.
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Comparison of changes in the VAS scores*
10
9
■ Non-regression
8 ■ Partial regression■ Complete resolution
■ Operated
7
6
**
5 **
4 8,16 7,95 7.92 8,16 *** ** **
**
3 **
5,5 *******
2 4,36 4,4
4,5
3,4
2,95 3,03
1 1,96 4
2 2 1,88
0
V1 V2 V3 V4
Fig. 3. Comparison of changes in the VAS scores over time between the groups. Lower values correspond to 
clinical improvement. Visits: baseline (V1); 1st month (V2); 3rd month (V3); 6th month (V4). * Mean. ** Sig-
nificant improvements in the VAS scores within the groups continued in all follow-ups (V2, V3, and V4) of par-
tial regression and complete resolution groups (p = 0.000). *** The operated group had significantly lower VAS 
scores at V2 and V3 than the other groups (p = 0.000). **** At V4, the VAS scores in the operated group were no 
different from those of partial regression and complete resolution groups (p = 0.812). VAS, visual analog scale.
Significant improvements in the ODI scores within the Discussion
groups continued in all groups during V2, V3, and V4 
(p < 0.05). The operated group had significantly lower In this study, we present the clinical and radiological 
ODI scores at V2 and V3 than the other groups (p = follow-up results of operated and nonoperated patients 
0.000). At V4, there was no significant difference in the with sequestered LDH. Approximately 90% of patients 
ODI scores between the partial regression and complete with LDH are reported to have achieved good or perfect 
resolution groups and the operated group (p = 0.800) results with conservative treatment [17]. Spontaneous re-
(Fig. 4). gression of disc herniation is a known phenomenon, and 
Table 1 shows the sequestered disc herniation volumes regression is more prevalent among sequestered disc her-
of all groups at V1 and V4. It can be observed that there nias [9, 10]. In this study, one-third of the patients under-
was no significant volume change in the nonregression went operation, and most of them had muscle weakness 
group, whereas the sequestered disc volume at V4 was 0 or severe pain. Clinical and radiological improvement 
mm3 in the complete resolution and operated groups. was observed in approximately 90% of nonoperated pa-
The average herniated disk volume (mean ± SD) in the tients with sequestered LDH who received conservative 
partial regression group decreased from 1,524.2 ± 558.5 treatment.
to 742.5 ± 351.6 mm3. Although the mechanism of spontaneous regression of 
disc herniation is not clearly understood, 3 hypotheses 
have been mentioned in the literature: first, the hernia-
tion could retract back into its main disc, which possibly 
occurs in disc bulging and disc protrusions [18]; second, 
Clinical and Radiological Results of Med Princ Pract 2021;30:244–252 249
Sequestered Lumbar Disc Herniation DOI: 10.1159/000515308
Table 1. Demographic and clinical features of the patients
Variable Total Nonregression Partial regression Complete resolution Operated p value
(n = 80) (n = 6) (n = 22) (n = 27) (n = 25)
Age, years1 47.7±10.2 46.5±12.8 47.0±10.5 46.3±10.3 50.2±9.4 0.527a
(48.0 [25–67]) (49.0 [25–62]) (47.5 [27–66]) (45.0 [27–67]) (50.0 [35–67])
BMI 26.8±4.4 26.5±4.8 26.4±4.1 26.3±3.5 27.7±5.5 0.661a
(26.3 [18.9–42.1]) (25.1 [21.4–34.6]) (26.7 [18.9–35.3]) (25.9 [20.3–35.1]) (27.1 [19.2–42.1])
Sex, n (%)
Female 45 (56.3) 1 (16.7) 12 (54.5) 19 (70.4) 13 (52.0) 0.102c
Male 35 (43.7) 5 (83.3) 10 (45.5) 8 (29.6) 12 (48.0)
Duration of pain (days),1 n (%) 5.0±7.5 5.7±9.0 4.9±7.3 6.2±8.4 3.7±6.5 0.189b
(2.0 [1–30]) (2.0 [1–24]) (2.0 [1–24]) (2.0 [1–30]) (1.0 [1–30])
Location of pain, n (%)
Low back 4 (5.0) 1 (16.7) 2 (9.1) 1 (3.7) 0 (0.0) 0.390c
Low back and right leg 36 (45.0) 2 (33.3) 7 (31.8) 15 (55.6) 12 (48.0)
Low back and left leg 40 (50.0) 3 (50.0) 13 (59.1) 11 (40.7) 13 (52.0)
Muscle weakness, n (%)
Baseline (V1) 18 (22.5) 0 (0.0) 3 (13.6) 3 (11.1) 12 (48.0) 0.003c
Follow-up (V4) 12 (15.0) 1 (16.7) 2 (9.1) 2 (7.4) 7 (28.0) 0.161c
Level of sequestered LDH, n (%)
L1–L2 3 (3.8) 1 (16.7) 0 (0.0) 1 (3.8) 1 (4.0) 0.767c
L2–L3 6 (7.4) 1 (16.7) 1 (4.5) 3 (11.1) 1 (4.0)
L3–L4 11 (13.8) 0 (0.0) 5 (22.8) 3 (11.1) 3 (12.0)
L4–L5 30 (37.5) 2 (33.3) 7 (31.8) 10 (37.0) 11 (44.0)
L5–S1 30 (37.5) 2 (33.3) 9 (40.9) 10 (37.0) 9 (36.0)
Volume of herniation (mm3)1
Baseline (V1) 1,441.0±682.5 1,476.0±884.7 1,524.2±558.5 1,245.6±738.2 1,521.2±548.8 0.245a
(1,321.7 [772.5–1,617.3]) (1,380.2 [764.0–2,018.2]) (1,411.3 [874.1–2,132.0]) (1,114.2 [684.0–1,997.5]) (1,382.3 [768.3–2,241.0])
Follow-up (V4) 1,069.0±599.6 1,396.0±847.6 742.5±351.6 
(896.3 [528.5–1,499.6]) (1,340.0 [812.0–1,988.8]) (452.2 [245.6–1,011.8])
LDH, lumbar disc herniation. 1 Mean ± standard deviation (median [minimum-maximum]). a One-way ANOVA. b Kruskal-Wallis test. c χ2 test.
VAS
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Comparison of changes in the ODI scores*
100
90
■ Non-regression
80 ■ Partial regression■ Complete resolution
■ Operated
70
60
** **
50
***
40 76,7 77,3377,2379,32 ** **
30 **58,58 ***** ****
46,7745,98 46,43
20 36,08 39,5
29,61 30,12
10 21,73 18,31 18,58 16,83
0
V1 V2 V3 V4
Fig. 4. Comparison of changes in the ODI scores over time between the groups. Lower values correspond to 
clinical improvement. Visits: baseline (V1); 1st month (V2); 3rd month (V3); 6th month (V4). * Mean. ** Sig-
nificant improvements in the ODI scores within the groups continued in all follow-ups (V2, V3, and V4) of par-
tial regression and complete resolution groups (p < 0.05). *** The operated group had significantly lower ODI 
scores at V2 and V3 than the other groups (p = 0.000). **** At V4, the VAS scores in the operated group were no 
different from those of partial regression and complete resolution groups (p = 0.800). ODI, Oswestry Disability 
Index; VAS, visual analog scale.
dehydration of the hernia [19]; and third, herniation extrusion (70%) than among patients with protrusion 
causing an inflammatory reaction and neovasculariza- (41%) and disc bulging (13%); moreover, disk sequestra-
tion in the epidural cavity and dissolving with macro- tion has a much higher complete resolution rate (43%) 
phage phagocytosis and enzymatic degradation [10]. The [10], suggesting that sequestered-type herniation is a pre-
third hypothesis has been described as being more per- dictive factor for spontaneous regression. Takada et al. 
suasive than the other 2 hypotheses for spontaneous re- [23] reported regression (>50% herniation size reduc-
gression [10, 20]. While dehydration contributes to a re- tion) in 100% and complete resolution in 44% of 18 se-
duction in the size of a herniated disc, it cannot adequate- questered LDH cases, as observed in the MRI scans taken 
ly explain the cases of complete regression of a free after 9 months. Macki et al. [11] studied 54 patients with 
fragment [21]. The mechanism mediated by inflamma- sequestered LDH and found that spontaneous regression 
tion may have a role in spontaneous regression because occurred within an average of 9 months and that regres-
the free fragment is more exposed to the peripheral circu- sion probability was the highest among the sequestered 
lation in the epidural space than in other types of hernia type compared with the other hernia subtypes. Ahn et al. 
[19, 22], resulting in immunological reactions [22]. [3] reported regression (>25% herniation size reduction) 
Spontaneous regression rates in LDH differ based on in 100% and complete resolution in 64% of 11 seques-
differences in experimental approaches and imaging tered LDH patients after an average follow-up period of 
methods, follow-up durations, and classification of disc 4.3 months. In our study, regression was observed in 89% 
herniation [7]. The spontaneous regression rates are and complete resolution in 49% of the patients in the non-
higher among patients with disc sequestration (96%) and operated group in the MRI scans taken at the 6th month. 
250 Med Princ Pract 2021;30:244–252 Sucuoğlu/Barut
DOI: 10.1159/000515308
ODI
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While the regression rates in this study are close to those In studies, comparing surgical and conservative treat-
reported in the literature, these rates may increase with ment in LDH treatment, it was shown that pain reduced 
longer follow-up durations. faster in the short term with surgery, but in medium- and 
The relationship between spontaneous regression of long-term follow-ups, both treatments have similar ben-
disc hernia and improvement of clinical outcomes is con- efits [28]. In this study, although the improvement in pain 
troversial [7, 10]. In addition to disc herniation, many and disability scores for sequestered LDH patients was 
physical and psychological factors of patients that may higher among the operated patients, they were found to 
affect clinical results may be the cause of this inconsis- be similar to those in patients with spontaneous regres-
tency [10]. Disc regression was not the only factor to be sion at the 6th month.
associated with clinical improvement; the clinical out-
come also showed improvement without regression [24]. Limitations of the Study
In addition, the definition of regression differs between The primary limitation of this study was that the fol-
studies; studies have defined spontaneous regression as a low-up duration was <1 year, despite having a standard 
reduction in the size of the disc hernia by >20% [25], 50% imaging time for control MRI. Therefore, the study is far 
[23], or 70% [12]. This makes it difficult to establish a re- from showing long-term results. Second, the number of 
lationship between clinical outcomes and regression. De- patients lost during the follow-up was relatively high. 
spite all this, complete resolution, significant high regres- This limitation may have affected clinical and radiologi-
sion rate, and rapid regression can be counted as factors cal results. Third, there is a lack of a standard definition 
for spontaneous disc regression that have better correla- in the literature for spontaneous regression. Fourth, as 
tion with clinical improvement [10, 12, 23]. Among the 8 the nonoperated patients received various conservative 
sequestered LDH patients in Takada et al.’s study [23] treatments, the results do not show the effect of any single 
and 75 sequestered LDH patients of Rahimizadeh and Sa- treatment.
ghri’s study [13] with complete resolution observed, all 
had good or excellent clinical results. Bazzao et al. [12] 
and Ahn et al. [25] found that a decrease in the size of the Conclusion
hernia by >70 and >20%, respectively, was associated with 
clinical improvement. In the current study, significant Partial regression or complete resolution was observed 
improvements in pain and disability scores were observed with conservative treatment in the 6th month post-MRI 
with a decrease in the hernia size of >25%. There was no in most of the nonoperated patients with sequestered 
difference in terms of clinical recovery between partial LDH. Improvements in pain and disability scores were 
regression and complete resolution. At the 6th month, higher among the operated patients at the early stage, 
patients with spontaneous regression became clinically whereas they were found to be no different in patients 
similar to operated patients. with spontaneous regression at the 6th month. Thus, we 
The incidence rate of neurological deficit (66.7%) [6] recommend that the conservative treatment be attempted 
in sequestered LDH being higher than other hernia sub- before surgery in patients with sequestered LDH without 
types may increase the prevalence of surgery. Despite this, absolute surgical indication or uncontrollable pain.
every surgical intervention without indication brings the 
risk of complications and relapses. Recurrence of up to 
8% and a complication rate of up to 9% after discectomy Statement of Ethics
have been reported [26]. Therefore, conservative treat-
ment is recommended for at least 2 months in LDH pa- The study protocol was approved by the Ethics Committee of 
tients with no absolute surgical indication, and surgery is Istanbul Gelisim University (Decision No: 19.04-20/05.08-17). The study was conducted in accordance with the rules of the Dec-
suggested to be considered if conservative treatment is laration of Helsinki, and all individuals gave written consent prior 
not successful [27]. In our study, the number of patients to participation.
with muscle weakness who underwent surgery was high 
as could be predicted, and significant improvements were 
observed in motor deficit postoperatively. The prevalence Conflict of Interest Statement
of complications in operated patients was not evaluated, 
but the recurrence rate (12%) was slightly higher than The authors declare that they have no conflict of interest.
that in the literature.
Clinical and Radiological Results of Med Princ Pract 2021;30:244–252 251
Sequestered Lumbar Disc Herniation DOI: 10.1159/000515308
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Funding Sources Author Contributions
This research did not receive any specific grant from funding H.S.: conceptualization, methodology, writing – review and ed-
agencies in the public, commercial, or not-for-profit sectors. iting, data curation, and formal analysis;  A.Y.B.: review and edit-
ing, data curation, and formal analysis.
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252 Med Princ Pract 2021;30:244–252 Sucuoğlu/Barut
DOI: 10.1159/000515308
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