Adolescent lumbar disc herniation: etiology, diagnosis, and treatment options

Abstract

Adolescent lumbar disc herniation (ALDH) is a type of disease with a much lower incidence than adult lumbar disc herniation (LDH), which has a trend of increasing year by year. If the diagnosis is not timely or the treatment is not appropriate, it will have a serious impact on the adolescent’s psychology. The etiology of ALDH remains unclear, and it is thought that trauma, genetic, immunity, developmental abnormalities, and biomechanical abnormalities contribute to the onset and accelerate ALDH’s progression. The diagnosis of ALDH is similar to that of adults, but it has its characteristics, such as a positive straight leg raising (SLR) test in nearly 90% of patients, and posterior apophyseal ring fracture (PARF) is considered a characteristic imaging finding of ALDH. First-line treatment for ALDH remains conservative, although it is less effective than in adults. With the development of regenerative medicine, more and more treatment methods for small traumas have been applied to ALDH and achieved satisfactory treatment results. In the case of the above treatment, the effect is not satisfactory, surgery has become the last choice, different from the earliest use of open discectomy combined with fusion surgery, now more and more surgeries tend to use spinal endoscopic operation to solve, especially patients combined with some high-risk factors, and achieved satisfactory results. With the deepening of ALDH research, the etiology and mechanism of ALDH may be more fully understood. At the same time, with the development of Artificial intelligence (AI) technology, it is believed that in the near future, AI can provide references in the timing of conservative treatment for ALDH, the selection of surgical modalities, and the prediction of postoperative complications.

Introduction

According to preliminary statistics, nearly 80% of individuals will experience lower back pain (LBP) at some point in their lives [1], and lumbar disc herniation (LDH) stands as one of the primary reasons for LBP, simply defined as the bulging or extrusion of nucleus pulposus material into the spinal canal. This condition arises from the gradual deterioration of spinal components, including the fibrous ring, nucleus pulposus, and the connective tissue of the lumbar intervertebral disc (IVD) [2]. It is estimated that approximately 1-3% of the population experiences this condition annually, particularly among those aged 30 to 50 [3]. A significant number of discs herniations are asymptomatic, 30% of individuals in their 20s and 84% of those in their 80s showed imaging signs of a herniated disc [3]. In a long-term observational study in Norway, an analysis of more than 30,000 cases of surgical treatment for LDH showed that more than 75% of patients were predominantly distributed between the ages of 30 and 59 [4]. Given the high incidence of LDH within the patient demographic, healthcare providers possess a solid understanding of its pathophysiology, clinical presentations, and diagnostic criteria, as well as the guidelines for surgical referrals [5]. To date, the majority of research on these changes has primarily focused on adult populations.

There is a scarcity of literature concerning adolescent lumbar disc herniation (ALDH). This may be linked to the low prevalence of LDH among adolescents, with documented rates as low as 0.5% [6] Although the features of ALDH bear resemblance to those seen in adult LDH, they are not entirely the same, particularly in terms of clinical presentations, imaging characteristics, and treatment strategies [7]. A notable observation is that approximately 90% of adolescents with ALDH display a positive straight leg raising (SLR) test [8], while neurological symptoms (numbness or weakness) are less frequently reported in younger populations [9]. The age limit for defining ALDH remains ambiguous, as human growth typically concludes by the second decade, with the epiphyseal cartilage merging completely with the vertebral body around age 21 [10]. This aligns with the guidelines put forth by the American Academy of Pediatrics [11]. Consequently, ALDH is generally defined to include individuals up to 21 years of age. Research indicates that most ALDH patients are between 13 and 20 years old, and those under 12 years old are relatively uncommon [12–17], with 51% aged 17 to 18, 46.5% between 13 and 16, and 2.5% aged 12 or younger [18]. This review aims to comprehensively discuss ALDH, reviewing its epidemiology, potential etiologies, pathogenesis, risk factors, diagnostic approaches, imaging traits, treatment options, and outcomes observed in recent decades.

Epidemiology

A retrospective study based on post-hospitalization imaging, evaluating 597 adolescents (mean age 10.75 ± 5.25 years), showed that prevalence of LDH of 5.8%, with prevalence rates of 2.9%, 2.9%, 17.1%, 57.1% and 65.7% from L1/2 to L5/S1, respectively. In addition, the prevalence of intervertebral disc degeneration (IVDD) of 2.2%, with rates of 27%, 30%, 30%, 40%, and 40% observed from L1/2 to L5/S1, respectively [19]. In contrast, the average prevalence of LDH and IVDD in adults were 14.18% and 44.23%, respectively [20]. Two retrospective analyses over 10 years found that the prevalence of ALDH was 3.5% (25/742, age 20 years or less) and 2.6% (121/6695, age 13 to 20 years), respectively [21, 22]. Furthermore, a data from the Korean military conscription examination also showed that the prevalence of ALDH was 0.6% (237/6695, aged around 19 years) [23]. Coincidentally, a population-based study based on the Korean National Military Recruitment Medical Examination Database in adolescent males, showed that lumbar stress injuries (spondylolysis) have increased substantially, and although spondylolisthesis rates declined due to alcohol control policies, chronic instability may elevate long-term risks of intervertebral disc herniation [24]. Although the prevalence of asymptomatic disc herniation among adolescents remains uncertain, there are instances of symptomatic herniation, aligning with reported rates in the literature ranging from 0.5–6.8% [6, 25].

Etiology and pathogenesis

The main causes of LDH are aging and mechanical insults, which have the greatest impact on IVD pathology, and its main histomorphology features include the occurrence of granular changes, structural alterations with tears and clefts, and a severe increase in acidic mucopolysaccharides [26]. However, the cause of ALDH is not very clear, and it is generally believed that the relevant factors include trauma, developmental abnormalities, genetic immunity, biomechanical abnormalities, premature degeneration of IVD, obesity, and environmental factors (Fig. 1).

Fig. 1.

Schematic representation of relevant factors that may contribute to ALDH

Trauma

Trauma (mainly sports-related or self-reported injuries) is often considered the most likely cause, and it has been reported that 30–60% of ALDH is associated with trauma or some kind of cumulative sports injury, especially in younger athletes [27, 28]. Whereas sports-induced injuries can result from a single blow or twist resulting in a fracture, strain, or sprain, as well as overuse injuries, which result from repetitive training and microtrauma [29]. This is in contrast to adult patients, who usually experience no trauma before the onset of symptoms for the most part. A study of 25 elite junior tennis players (mean age 13 ± 1.7 years) found that 64% of the athletes had at least one lumbar spine abnormality, including disc degeneration in 44%, pars abnormalities in 36%, bone marrow edema in 24%, and disc herniation in 20% [30]. The prevalence of disc degeneration in young elite skiers (mean age 20 years) is significantly higher than in non-athletes (mean age 19 years), which is consistent with previous studies on other young athletes (wrestlers, gymnasts, etc.), which may be due to excessive and prolonged physical training when the skeleton is immature, resulting in spinal overload and repeated microtrauma to the intervertebral discs and vertebrae, which in turn can lead to spinal abnormalities [31]. Notably, a male taekwondo blue-belt as young as 7 years of age developed L3/4 LDH with multilevel degenerative changes following unwarmed jump-kick maneuvers. The injury resulted from repetitive trauma involving rotational-flexional forces during kicking combined with compressive loading from jump-landing on discs [32]. However, recent research suggests that trauma is not a major contributing factor, but rather may be a triggering event for the deterioration of preexisting lesions in the disc [33]. Baranto et al. [34] demonstrated in a porcine lumbar spine model that experimentally-induced degenerated discs withstood twice the compressive load of normal discs under axial loading (attributed to nuclear fibrosis altering stress distribution), yet required significantly lower failure loads in extension than in flexion, with the growth zone consistently remaining the most vulnerable site. In addition, trauma in athletes can cause intradiscal hematoma, which probably is another etiology for disc degeneration [35]. Similarly, Bovine caudal disc experiments demonstrate that axial torsion selectively compromises the intralamellar matrix (within-lamella support), resulting in a decrease of nearly 50% in strength and stiffness and significantly increasing the risk of fissure and disc herniation [36]. Further evinced by Veres et al. [37] in an ovine lumbar model, combined torsion (2°) and flexion (7°) loading significantly lowers disc injury pressure thresholds, predominantly inducing central posterior radial tears with endplate involvement, whereas pure flexion triggers diffuse annular rupture. Collectively, torsion is established as the key mechanical driver for matrix degradation and distinct pathological failure modes. Moreover, the IVD is attached to the endplate by Sharpey’s fibers and separated from the rest of the vertebral body by a cartilage growth plate, where ossicular ring ossification is usually completed around the age of 21, before this, adolescent spine development is not yet complete, the endplate osteochondral junction area is relatively weak, susceptible to compression and tensile stress, trauma may lead to lumbar marginal plate avulsion, resulting in fibrosis, which may trigger a series of clinical symptoms [38].

Developmental abnormalities

The lumbar facet joint (FJ) is a complex three-dimensional structure that acts as a bone stabilizer for the posterior spine in multiplanar biomechanical capabilities (Fig. 2) [39]. Facet articular orientation as an existing morphological factor in degenerative spondylolisthesis, which is proposed to increase the risk of degenerative disc diseases [40]. There are studies to confirm that in the presence of tropism in the FJ, the fibrous rings on the larger side of the coronal plane may be subjected to higher compressive loads and rotational stresses, and the ability of the IVD to resist shear force decreases, which may accelerate the degradation of the FJ and IVD [41]. A radiographic analysis of 191 adolescent patients with low back pain showed that the incidence of axial FJ was significantly higher in male patients aged ≥ 15 years, especially at L4/5 [42]. The FJ in ALDH is asymmetrical, with a difference of more than or equal to 10° in the L4/S1 segment, which is highly correlated with ALDH [43]. Facet tropism (FT) was present in 16 of the 39 segments (41.0%) in patients with L4/5 LDH and in 12 of the 27 segments (44.4%) in patients with L5/S1 LDH. Especially when ALDH occurred at the L5/S1 segment, there was a significant difference in the values of the transverse angle between the right and left sides. The large height of the FJ surfaces, small thickness of the FJ space, and asymmetry of the FJ suggest that LDH is likely to occur [44].

Fig. 2.

Schematic diagram of the lumbar facet joints

O is the centre of the lumbar vertebrae, AO = OB, and C and D are the vertices of the two peaks of the superior articular facets respectively, aR = right facet angle, aL = left facet angle, Facet joint orientation (FO) is the angle of the facet joint relative to the coronal plane in the transverse view, FO = (aR + aL)/2, facet tropism (FT) is defined as an asymmetry between the left and right facet angle angles, FT=|aR-aL|.

The lumbosacral junction distributes the load of the entire lumbar spine to the hip joint in a unique pattern, which is very important for maintaining the natural biomechanics of the lumbar spine [45]. The lumbosacral transitional vertebrae (LSTV) is usually considered to be sacralization of the 5th lumbar vertebra or lumbarization of the 1st sacral vertebrae, with prevalence rates ranging from 1.7 to 14%, and 3.4–7.2%, respectively [46, 47]. A retrospective analysis of ALDH (aged 14 to 20 years) showed that LSTV accounted for 30% of the 80 cases and was associated with L4/5 disc herniation [48]. Shortened pedicles constitute a core anatomical factor in congenital spinal stenosis (CSS), proportionally reducing spinal canal diameter and cross-sectional area [49]. Compared to healthy individuals (mean 9 mm), pedicle length in CSS patients is reduced by nearly 28% (mean 6.5 mm) [50]. This congenital pedicle shortening flattens (compresses) the spinal canal, predisposing to the characteristic trefoil-shaped spinal canal morphology, particularly when concurrent lateral recess stenosis is present. Crucially, unlike the typically single-level (predominantly L4/5) involvement in degenerative lumbar spinal stenosis, stenosis due to congenitally short pedicles demonstrates diffuse involvement throughout the lumbar spine [51]. ALDH is also associated with the height of the interridge line and the length of the L5 transverse process, too high affects the L4/5 disc herniation and too low affects the L5/S1 disc herniation, which may be due to the abnormal morphology of the iliopsobar ligament disrupting the stress transmission balance between the L4, L5, and S1, impairing the stability of the lower lumbar spine (Fig. 3) [52]. Adolescent idiopathic scoliosis (AIS) is the common form of scoliosis, with an overall prevalence of 0.47–5.2%, and its disc degeneration is more severe than that of healthy individuals, which is a risk factor for LDH, but due to the small sample size, the difference is not significant [53, 54].

Fig. 3.

Schematic diagram of the relationship between iliac spine height and the lumbosacral vertebrae

EF is the line connecting the vertices of the bilateral iliac spines, AB is the length of the transverse process from the midpoint of L3 to the tip of the L3 transverse diagram, and CD is the length of the transverse process of L5.

Genetic immunity

LDH has a tendency and genetic susceptibility [55]. It has been reported that researchers used linkage analysis to investigate the co-inheritance of the Trp2 allele and IVDD in the families of four patients with alleles. The findings showed that everyone with the allele had IVD disease, suggesting a link to a dominant genetic disorder [56]. Familial aggregation is more common among adolescents than among adults, a family history of clinical LDH has been reported in 24–46% of ALDH patients, but only in 18–29% of adult patients [57], and patients with a positive family history have a 5-fold risk of LDH before the age of 21 [58]. In a retrospective analysis of 104 patients with LDH (under 25 years old), 18 patients had a clear genetic history, most of whom were first-degree relatives, which was statistically significant [59]. A positive family history is a potential risk factor, and this association may be due to the presence of weak connective tissue compared to the general population, predisposing to degenerative changes in the spine and disc herniation at a young age [21].

Premature degeneration of IVD

It has to be admitted that early histopathological degeneration of lumbar IVDs begins at the age of 11, and the water content of the IVD begins to decrease in childhood [60, 61]. IVDD progresses with increasing age and persistent degeneration under pathological injury, which is associated with reduction intrinsic self-healing capacity of tissues, including decreased nucleus pulposus progenitor cells [62]. Some studies suggest that the occurrence of Schmorl’s Nodes (SNs) is positively correlated with the degree of lumbar disc degeneration [63], and that IVDD could appear as early as the first decade of life with SNs [19]. Lee et al. [64] performed histological examination on the postoperative specimens of 15 patients with LDH (under 20 years old), and found that all cases had signs of IVDD, of which 11 cases (73%) had significant changes. High-intensity zone (HIZ) lesions are defined as high-intensity signals in the T2 WI image located in the posterior fibrous ring substantially, which is brighter than the nucleus pulposus (NP) [65]. HIZ manifests as granulation tissue or disruption of disc material can stimulate areas of pain, may indicate disc calcification, leading to increased inflammation and biomechanical changes, resulting in LDH [66]. Modic changes are a series of degenerative changes involving the vertebral body endplate and adjacent vertebral bodies, usually located near the degenerative disc and the 2 lowest segments [67]. A study of young adults (18 to 20 years of age) showed HIZ and Modic changes of 3.2% and 0.7%, respectively [68]. Coincidentally, the prevalence of HIZ lesions was highest in the lowest two lumbar segments, consistent with the phenomenon observed in IVDD [69]. One 17-year follow-up showed that IVDD detected in adolescence increased the risk of LDH and the strength of NP herniation in adulthood [70].

Other factors

Obesity

Obesity, particularly the distribution of obesity in the trunk, is strongly associated with biomechanical changes in the injured spine, which may be used as a potentially closely related cause of lumbar degeneration [66]. In a retrospective study of 194 ALDH, found that HIZ (20.0% vs. 6.1%) and SNs (90.0% vs. 63.4%) has a significantly higher in the obese group [71]. Based on disease cohort studies (mean age 15.89 ± 1.36 years), patients with BMI greater than 30 kg/m2 were found to be 7 times more likely to undergo lumbar discectomy [72]. People with high BMI are prone to LDH, which may be related to the use of extreme postures to reduce symptoms, and higher torque and compression on lumbosacral discs and joints by increasing the lumbosacral angle [59]. Being overweight is also associated with high levels of cholesterol and blood lipids, which may enhance atherosclerotic processes in the vessels of the lumbar spine, accelerating the degeneration of the discs and ultimately LDH [73].

Environmental factors

The interaction of environmental and genetic factors accelerates degradation [74]. Factors such as abnormal load of mechanical stress affecting the microenvironment, ischemic NP, exercise, and lifestyle all play an important role in the development of IVDD [75]. Certain sports with high impact or severe loads lead to abnormal mechanical loads and stresses, accelerate disc degeneration, and trigger LDH [23, 75, 76]. In addition, type B of sitting posture and sitting for more than 6 h a day are high-risk factors for LDH in adolescents and young adults [59]. A survey of 47,724 adolescents (aged 14 to 18 years) on health-related behaviors showed that adolescent smoking, high BMI, monthly alcohol abuse, increased the likelihood of hospitalization for degenerative low back pain in adulthood and the chances of spinal surgery [77]. Heavy smoking not only led to significantly increased pain values, but also increase the degree of degeneration of the lumbar spine and recurrence of paracentral hernia LDH [78, 79]. The microenvironment of IVD is complex, NP is the largest non-vascular organ in the vertebrate body, resident cells only rely on the diffusion of adjacent capillaries (8 mm away) to transport nutrients and remove metabolic waste, this creates a challenging situation for NP cell survival in this unique in vivo microhabitat [75, 80, 81]. The nicotine in tobacco make the vasoconstriction and the bone-intervertebral disc junction separate, which in turn inhibits the synthesis of proteoglycans, which greatly affects the speed of IVD metabolism, resulting in extracellular matrix (ECM) and NP cell hypoplasia, all of which will lead to the degenerative changes of IVD [82, 83].

Diagnostic and imaging characteristics

Diagnostic

LBP is the chief complaint for the majority of ALDH upon initial presentation [2, 22, 84], which can range in severity from mild back pain to severe neurologic deficits, contingent upon the location of the nucleus pulposus protrusion [85, 86]. Particularly significant is that chronic, progressive back pain awakening the patient from sleep at night is a classic presentation of spinal cord neoplasms [87]. Given the complexity of the etiology of LBP, spine surgeons should not only establish the diagnosis of LDH but also differentially diagnose other conditions, including early-stage lumbar spondylolysis, spondylolisthesis, Scheuermann kyphosis, discogenic pain, FJ arthritis, lumbar epiphyseal ring fracture, neoplasms, scoliosis,,and muscle strain, all of which necessitate a comprehensive medical interview, meticulous physical examination, and appropriate diagnostic imaging to elucidate the underlying cause [28, 88]. Among these, obtaining a thorough and detailed medical history to identify potential risk factors for LDH constitutes the foundational and critical initial step prior to initiating further investigations [89]. Includes a complete personal history, and chief complaints, with a particular focus on current history, evaluation and analysis of the patient’s symptoms, including onset, course, and duration of illness, probable causes, and analysis of other key neurologic symptoms, including low back and or leg pain, symptoms of motor, sensory, or sphincter influences, in addition to family history, past medical history is also included [90]. Detailed examination can infer the site of pathology by the expected motor function corresponding to the predicted nerve root and any defects corresponding to a specific dermatome, including the SLR test, the contralateral SLR test, the femoral nerve traction test, and the arc sign, among others [85]. SLR is a sensitive test, with a positivity rate of 88% in patients younger than 30 years old and 100% in patients aged 10–19 years old [91]. Differences in SLR positivity rates in different age groups of LDH may be related to the hamstrings, which are stronger and have thick fascia in younger patients [92]. Therefore, it is recommended to first determine whether hamstring tension is a limiting factor before performing an SLR test [92]. Considering the young age of the patient and the excellent ability to image cross-sectional soft tissues, Magnetic Resonance Imaging (MRI) is considered the gold standard for the evaluation of ALDH. Of note, DR (Digital Radiography) or CT (Computed Tomography) of the spine may be supplemented in cases where initial imaging findings suggest structural abnormalities (AIS), and MRI with contrast is indicated if infection or malignancy is suspected [89, 93, 94]. A rare case will develop tight hamstring syndrome, which is characterized by abnormal gait and needs to be paid attention to [95]. Another rare case, Fibrocartilaginous embolism (FCE) in children, a spinal cord infarction caused by retrograde embolization of intervertebral disc material, with weakness or paralysis (100%) as initial symptoms, followed by weakness or paralysis (48%), and 50% triggered by strenuous exercise, often with SNs (24%). No disease-specific therapies exist, and prognosis is generally poor, with only 4% of patients achieving completely recovery [96].

Imaging characteristics

The characteristics of ALDH are a soft protruded disc, no severe spinal degeneration [22]. Comparison of MRI features in 250 ALDH (mean age 17.3 ± 2.1years) showed that herniated NP were concentrated at L4/S1 (66.8%) and epiphyseal ring separation (ERS) concentrated at L4/S1 (30%) [97]. ERS accounts for more than 28% of adolescents and may be one of the pathoanatomical phenotypes of ALDH [98], with more severe LBP and radiating pain, with a particular focus on L5/S1, which may be related to the fact that the upper endplate of S1 is the most commonly affected site [99]. In terms of sensitivity, CT scanning is more accurate than MRI, which only recognizes 22% of lesions [100]. According to the location of annular process fractures, Takata and Epstein et al. [101, 102] divided it into type IV. Type I, an arcuate fragment without osseous defect. Type II, an avulsion fracture that includes a rim of bone. Type III, a localized fractures in which the defect is larger than the fracture fragment. Type IV, a fracture that extends both beyond the margins of the disc and the full length of the vertebral body between the end plates, type III and IV fractures appear to be more common after the age of 18 years. A systematic review and meta-analysis of the prevalence of MRI in children and adolescent spinal abnormalities (involving 2373 participants, ages from 4 to 19 years), showed that the pooled prevalence in nonathletes without LBP, participants with LBP, and athletes without LBP was respectively 22%, 44%, and 22% for disc degeneration, 1%, 38%, and 13% for herniated discs, 5%, 22%, and 11% for endplate changes [103]. Another change is that SNs can be observed in imaging of ALDH, with a prevalence of 2.68% [19], more commonly seen at the endplates of fractured vertebrae [104], which is mainly concentrated at L3/4, while SNs are less common in the L5/S1, a finding similar to that found in adults [63]. This may be related to the possibility that the upper lumbar spine is more likely to be injured and further illustrates the possibility that trauma is a risk factor for the development of SNs [105]. In addition, ALDH with unilateral neurological symptoms can also manifest as symmetrical atrophy of bilateral multifidus, which is more likely to cause LBP [106].

Treatment options

Conservative treatment

Conservative treatment is used as the first-line treatment for ALDH without neurologic deficits [86], with a short- to long-term success rate of 25-50% [107]. The goals of ALDH treatment are to relieve symptoms, allow for the earliest possible return to normal life, and prevent further lumbar disc degeneration [108]. Conservative treatment mainly includes restriction of activities, strict bed rest, and physical therapy such as intermediate frequency physiotherapy, analgesics, muscle relaxants, and epidural steroid injections as appropriate in the acute phase, and lumbosacral soft corset support if necessary [109], which requires more departmental collaboration than surgery, involving interdisciplinary management between orthopedic spine/sports medicine departments and anesthesia pain services. A retrospectively analyzed a total of 51 ALDH under the age of 20 (27 conservative treatment and 24 surgical treatment), with an average follow-up time of more than 5 years, and found the result of two groups were similar [110]. Although the conservative treatment effect of ALDH is not as significant as that of adults, and the effect is relatively worse than that of surgical treatment, it is still used as a first-line treatment for ALDH [33, 108, 111].

Intradiscal therapy

This intermediate treatment between conservative and surgical procedures aims to achieve relatively satisfactory results with minimal invasive maneuvers. A considerable number of patients opt for alternative treatments such as epidural injections, leading to over $100 billion in healthcare expenditures annually [ 112 ]. A retrospective study of 26 ALDH (mean age 21.1 years) treated with chemonucleolysis found that chemonucleolysis was effective and safe for ALDH [ 113 ], characterized by less trauma and postoperative adhesions, shorter hospital stays, lower cost, and less surgical risk [ 13 ].

Platelet-rich plasma (PRP) is an autologous active substance that contains a large number of growth factors, which stimulates cell proliferation, enhances cell function, and slows down cell death [114]. PRP has been used in adolescent-related conditions, such as rotator cuff injuries, late-stage femoral head necrosis, and isolated meniscus injuries, with good results [115–117]. PRP can be used to treat LDH due to its endogenous healing effect, and patients who have been fractionated treatment have seen significant improvement in clinical symptoms and function [118]. Although there have been no clinical reports on the use of PRP alone in ALDH, the efficacy and safety of PRP has been proven, which can be used as a promising therapeutic measure [119].

In contrast to PRP, stem cells (SCs) requires the use of sophisticated techniques to isolate and culture embryonic or adult cells and use these cells to produce growth factors and cytokines that can be used for tissue repair, and are commonly used in the treatment of inflammatory and degenerative related diseases [120]. There have been clinical studies on the use of mesenchymal stem cells (MSCs) to treat LDH, and after 2 years of follow-up, the excellent rate has reached 90.9% [121]. Regenerative medicine, a branch of research that involves the replacement of human tissues to restore and establish normal function, which is believed to be great developments in the future.

Surgical treatment

Surgical treatment can be the last choice for the ineffective treatment methods mentioned above (Table 1) [33, 84, 111, 122–127]. Although indications for surgery vary, surgery is indicated when non-surgical treatment fails (including conservative treatment for more than 6 weeks), patients develop neurologic deficits or intractable pain or cauda equina syndrome, or are associated with spinal deformities [125–127]. The average time from pain onset to surgery in adolescents is 12.2 months [18], with surgery rates ranging from approximately 0.6–2.5% of all LDH surgeries, and reoperation rates ranging from approximately 10–28%, similar to the prevalence in adults [6, 15, 128]. The surgical methods of ALDH, mainly including posterior lumbar interbody fusion (Table 2) [52, 84, 129–133], microdiscectomy (Table 3) [18, 84, 87, 90, 91, 134–144], and spinal endoscopic (Table 4) [108, 145–164]. For adolescent patients with severe bone spurs, extensive rupture of the central disc or severe slippage, lumbar intervertebral fusion has good results and few complications [23]. while early microscopic discectomy does not significantly interfere with the structural integrity of the lumbar spine, and is a safe and effective treatment [135]. In contrast, percutaneous endoscopic lumbar discectomy (PELD) has achieved similar good results to open discectomy, characterized by the preservation of normal spinal structures such as ligaments, muscles, lamina, and facet joints, minimizing the impact on adolescent growth, especially L4/S1, with the highest incidence of ALDH, and providing satisfactory clinical results for young patients who have reoperated [165, 166]. In a study evaluating discectomy outcomes, 86% of patients aged 18 years and younger were satisfied with the results, compared with 78% of patients aged 19 to 39 years and 76% of patients aged 40 years and older [6]. Specifically, a significantly greater proportion of adolescents achieved marked reductions in both leg and back pain at 1 or 2 year follow-up (mean = 1.7 years) relative to adult counterparts [6, 134]. Surgeons typically permit return to full activity levels within 8–12 weeks postoperatively, once pain-free range of motion and muscle strength are restored [167]. Cordover et al. [144] retrospectively analyzed the return to play (RTP) of 38 young athletes (under 21 years old) who underwent lumbar microdiscectomy and found that the average interval between symptom onset and surgery was 11 months, with an average postoperative follow-up of 51 months, 27 patients (71%) RTP at an average of 4.5 months postoperatively, and that 26 of those (96%) who did RTP achieved the same or higher level of competition. Furthermore, in cases with a history of competitive sports, 60% of the microdiscectomy group (mean age 16.6 years) returned to physical activity compared with 33.3% of the open microdiscectomy group (mean age 16.8 years) [87]. Similarly, an elite rugby player who underwent percutaneous endoscopic discectomy (PED) at the L5/S1 level under local anesthesia had his low back and leg pain resolved immediately after the procedure, began rugby recovery training after systematic physical therapy, and returned to the field of play 4 months after surgery [168]. However, a systematic review and meta-analysis of elite athletes returning to competition after surgical versus non-surgical treatment of LDH concluded that there was no significant difference in RTP rates between the two modalities, and that surgical treatment did not show a faster RTP time [169]. The RTP rate of different sports is different, and this result is limited by the physical demands of the sport, the motivation of the athlete, the age and other factors, and there are successful RTP cases in the surgical and non-surgical treatment of LDH in athletes, but the surgery is risky, and the treatment plan needs to be weighed by both doctors and patients and make joint decisions [170]. Of note, regardless of the option chosen, maintaining the integrity of the inner portion of the ring is particularly important for ALDH [171]. In addition, ALDH is mostly associated with sports trauma, and minimally invasive techniques (endoscopic and microdiscectomy) can rapidly improve patients’ symptoms, with low complications and recurrence rates, and have good short-term efficacy, and the willingness to treat ALDH in surgical treatment seems to be stronger than before [135, 172–174]. However, comparative studies of different treatment modalities, particularly surgical versus conservative management, are still insufficient. Large-scale prospective studies are urgently needed in the future to provide a more reliable basis for treatment decisions [173].

Table 1.

The summary of representative studies and characteristics of conservative, intradiscal and surgical treatments

treatment Modality	Representative studies	NO. patients	Age (mean)	comparative therapy	Follow-up (months)	conclusion	Pointer or advantage
Conservative treatment	Kurth et al. [122]	33	Under 20	lateral hemilaminectomy	64.8	No significant difference between the two groups	I. The NP of ALDH has a high water content and a soft and viscous texture, making it difficult to dry and reabsorb like a degraded adult IVD. II. The presence of ERS at this age stage can lead to a fracture of the epiphyseal ring in response to traumatic factors, resulting in the formation of a large non-elastic mass. III. There are uncertainties and slightly worse adherence after surgery, and there may be the possibility of iatrogenic lumbar instability and adjacent hernias [33, 111].
Intradiscal therapy	Kuh et al. [84] Xu et al. [124]	185 124	18.4 56	Microsurgical discectomy/PLIF Steroid	More than 12 12	Chemonucleolysis is the first choice for the treatment of soft ALDH PRP may be a safer alternative	I. Leg pain is more than back pain. II. Significant SLR limitation (SLR ≤ 45°). III. Imaging examination of soft disc herniation. [84]
Surgical treatment	Wiley et al. [123]	76	14.9	Conservative treatment	7.7 ± 8.1	L4 canal diameter (CD) < 12.6 mm and a L5 CD < 12.36 mm were highly correlated with the need for decompression	I. Severe pain that cannot be relieved after 6 weeks of conservative treatment. II. Disabling pain that affects daily activities. III. Cauda equina syndrome. IV. Progressive neurological deficit. V. Related spinal deformity Surgery, such as spondylolisthesis, multi-level disc disease, spondylolysis, and facet joint insufficiency [125–127].

(*PLIF, posterior lumbar interbody fusion)

Table 2.

Discectomy with fusion on adolescent lumbar disc herniation in the literature report

Study	Year	NO. Patients	Age (mean)	Follow-up (months)	Success rate (%)
Dang et al. [52]	2015	18	16.9	39.1	89.5
Kwon et al. [132]	2013	18	18.3	36.4	94.4
Kuh et al. [84]	2005	33	18.4	at least 12	89
Ebersold et al. [133]	1987	14	15.2	18.2	85.7
Leong et al. [129]	1982	20	18	52	95
Grobler et al. [130]	1979	23	17.6	63.6	87
Bradford et al. [131]	1969	16	13–18	3-108	92.9

Table 3.

A study of microdiscectomy for adolescent lumbar disc herniation in the literature

Study	Year	NO. Patients	Age (mean)	NO. level	Surgical modalities	Follow-up (months)	Success rate (%)	Conclusion
El-Qad et al. [90]	2023	6	rang10-19	L4/5 L5/S1	microdiscectomy	12	83.3	Microdiscectomy is an effective treatment for ALDH compared with conservative treatment in adolescents.
Güçlühanm et al. [137]	2022	9	14.6	L4/5 (55%) L5/S1 (44%)	minimally invasive open	12	100	Minimally invasive open is a safe and effective treatment for ALDH.
Erdağ et al. [138]	2022	18	17.1	L4/5 (61%) L5/S1 (39%)	microdiscectomy	36.8	82.8	Microdiscectomy can help ALDH combined with scoliosis achieve good functional outcomes.
Cordover et al. [144]	2022	38	19	L3/5 (2.6%) L4/S1 (15.8%) L4/5 (39.5%) L5/S1 (42.1%)	microdiscectomy	51	97.3	The prognosis for returning to competitive sports after lumbar microdiscectomy in young athletes is good
Shimony et al. [87]	2021	48	16.7	L4/5 L5/S1	microdiscectomy	12	79	Minimally invasive techniques are demonstrably safe and useful in adolescent population.
McAvoy et al. [135]	2019	199	16	L4/5 (60%) L5/S1 (43%) Others (10%)	microdiscectomy	98.4	72.9	Microdiscectomy for adolescent patients with symptomatic lumbar disc disease who have failed conservative treatment.
Montejo et al. [139]	2018	12	17	L4/5 (25%) L5/S1 (75%)	minimally invasive tubular	26.4	91	Minimally invasive tubular is safe and effective for adolescent LDH after failure of conservative treatment.
Menger et al. [140]	2018	16	16.75	L4/5 (41%) L5/S1 (53%) Others (6%)	minimally invasive tubular	6	82.4	Minimally invasive tubular surgery is safe and effective for carefully selected adolescent patients.
Gulati et al. [134]	2017	97	17.5	L2/3 (1%) L3/4 (2%) L4/5 (57%) L5/S1 (40%)	microdiscectomy	12	86.2	Microdiscectomy is effective and safe for LDH in adolescents and adults
Kim et al. [142]	2015	1	10	L5/S1 (100%)	microdiscectomy	6	100	The possibility of LDH combined with posterior apophyseal ring separation should be kept in mind in even young child.
Çelik et al. [143]	2011	32	15 ± 3.2	L4/5 (50%) L5/S1 (50%)	microdiscectomy	83	100	Microdiscectomy is effective and safe for LDH, and neurological recovery is more significantly in adolescents than in adults.
Thomas et al. [141]	2011	6	rang14-17	L4/5 L5/S1	minimally invasive tubular	10.2	100	Minimally invasive tubular surgery is an effective option for adolescent patients in whom conservative measures have failed.
Fakouri et al. [136]	2009	6	14	L4/5 (67%) L5/S1 (33%)	microdiscectomy	13	100	Microdiscectomy is the appropriate treatment for adolescents presenting with radiculopathy as a result of a herniated lumbar disc.
Cahill et al. [18]	2010	87	16.6	L3/4 (7.0%) L4/5 (45%) L5/S1 (36%)	minimally invasive open	12.5	95	Minimally invasive open is effective, with a low complication rate for adolescent patients with a neurological imperative for surgery.
Ozgen et al. [91]	2007	17	15.2	L4/5 (71%) L5/S1 (29%)	microdiscectomy	60	100	Microdiscectomy for ALDH can achieve satisfactory results with careful preoperative evaluation.
Kuh et al. [84]	2005	94	18.4	L4/5 (63%) L5/S1 (23%) Others (14%)	microdiscectomy	12	98	Microdiscectomy is useful in adolescents of severe extruded disc, sequestered disc, and LDH combined with bony spur.

(*ALDH, adolescent lumbar disc herniation; LDH, lumbar disc herniation)

Table 4.

A study of spinal endoscopic surgery for adolescent lumbar disc herniation in the literature

Study	Year	NO. Patients	Age (mean)	NO. level	Surgical modalities	Follow-up (months)	Success rate (%)	Complications	Conclusion
Feng et al. [146]	2024	199	18.5	L3/5 (1%) L4/S1 (0.5%) L4/5 (52.3%) L5/S1 (43.2%) Others (3%)	FELD	44.9 ± 18.6	91.5	transient dysesthesia persistent hyperesthesia post-operative transient dysesthesia recurrence of LDH	FELD for LDH in young adults is safe and effective.
zhang et al. [145]	2023	1 (BMI > 30 kg/m2,with PRAF)	15	L4/5	PELD	15	100	none	PELD is a safe and effective minimally invasive treatment for ALDH with PRAF.
Wang et al. [148]	2023	26	18.56	L3/4 (40%) L4/5 (30%) L5/S1 (30%)	PELD	3	87.5	nerve root injury/ureteral injury	PELD is uniquely superior in the treatment of ALDH.
Qu et al. [149]	2023	19 (BMI ≥ 30 kg/m2)	16.5	L4/5 (42%) L5/S1 (58%)	PELD	12	100	recurrence of LDH	PELD procedure is a safe and feasible method for treating LDH in obese adolescents.
Wu et al. [150]	2023	12 (with PRAF)	18.33	L4/5 (42%) L5/S1 (58%)	PELD	12	100	none	PELD is a safe and effective way to solve PRAF (type III) accompanied by ALDH.
Bajaj et al. [151]	2022	3	16	L4/5 (100%)	PELD	24	100	none	PELD can reduce tissue damage and help adolescents recover as soon as possible.
Mao et al. [152]	2022	44 (with high iliac crest)	17.7	L5/S1 (100%)	TELD	17.4	97.7	disc pseudocyst	TELD is an effective and valid option for ALDH with high iliac crest.
Yu et al. [153]	2021	28 (BMI ≥ 30 kg/m2)	18.07	L4/5 (75%) L5/S1 (21%) Others (4%)	FELD	27.75	89.3	abnormal sensation in the right calf	FELD is a safe and effective technique for treating obese adolescent patients with LDH.
Yu et al. [154]	2021	78	17.99	L4/5 (51%) L5/S1 (42%) Others (7%)	PELD	32.31	97.5	transient postoperative numbness	PELD is more advantageous for rapid symptom relief and improving postoperative quality of life in adolescent.
Mao et al. [155]	2021	16 (double-level contiguous)	19.3	L2/4 (6%) L3/5 (44%) L4/S1 (50%)	PELD	17.3	93.75	none	PELD is promising treatment strategy for symptomatic double-level contiguous adolescent with LDH.
Huang et al. [156]	2021	22 (with LSTV)	19.5	L4/5 (68%) L5/S1 (32%)	PELD	18	90.9	none	PELD is a safe and effective way to treat ALDH accompanied LSTV.
Lin et al. [108]	2021	10	15.6	L4/5 (40%) L5/S1 (60%)	PELD	12	95.8	none	PELD is a safe and effective surgical procedure to relieve pain and reduce disability in adolescents.
Yamaya et al. [157]	2020	18 (athletes)	17	L3/4 (6%) L4/5 (83%) L5/S1 (11%)	PELD	27	94.4	recurrence of LDH	PELD is minimally invasive and achieved a good clinical outcome in high school athletes.
Patgaonkar et al. [158]	2020	1 (obese, hypertensive)	18	L2/4 (100%)	Transforaminal endoscopic spine surgery	24	100	none	Transforaminal endoscopic spine surgery had good functional outcomes in adolescents.
Liu et al. [159]	2019	43	18.02	L4/5 (47%) L5/S1 (53%)	PTED	18.33	93	none	PTED is an effective and safe surgical method for the treatment of adolescent patients with LDH.
Chen et al. [164]	2018	19	15.7	L4/5 (32%) L5/S1 (63%) L4/S1 (5%)	PED	41.7	94.7	recurrence of LDH	PED may yield favorable results in the treatment of ALDH in terms of short- to medium-term follow-up.
Li et al. [160]	2018	48	18.96	L3/4 (8%) L4/5 (54%) L5/S1 (38%)	PELD	68.87	89.8	none	PELD is more advantageous for lower back pain than MED in adolescents with LDH.
Tu et al. [161]	2018	28 (with Scoliosis, Cobb’s angle was ≥ 10°)	17.8	L4/5 (75%) L5/S1 (25%)	FEID	36.5	93.3	transient postoperative sensory delay	FEID can achieve satisfactory clinical efficacy in the treatment of ALDH
XU et al. [147]	2018	23	15.4	L5/S1 (100%)	PEID	19.7	86.9	unilateral leg numbness after surgery	PEID is a safe and effective minimally invasive technique for ALDH at the L5/S1 level
Wang et al. [162]	2014	29	16.4	L4/5 (31%) L5/S1 (69%)	PEID	19.7	91	none	PEID showed satisfying outcomes with minimal complications in adolescents with LDH
Mayer et al. [163]	1996	4	13	L4/5 (75%) L5/S1 (25%)	PED	36	100	none	PED preferred for adolescent patients in whom conservative treatment failed

(*ALDH, adolescent lumbar disc herniation; FELD, full-endoscopic lumbar discectomy; LDH, lumbar disc herniation; LSTV, lumbosacral transitional vertebrae; MED, microendoscopic discectomy; PED, percutaneous endoscopic discectomy; PEID, percutaneous endoscopic interlaminar discectomy; PRAF, posterior ring apophysis fracture; TELD, transforaminal endoscopic lumbar discectomy)

Summary and prospect

The incidence of LDH is increasing year by year, and there is a trend of younger people [40]. It is challenging to develop an individualized plan suitable for each young patient, which includes not only for the conventional treatment of LDH, but also for long-term psychological intervention, especially for patients under 18 years of age. Artificial Intelligence AI (AI) technology has been used to predict various complications of spinal surgery and achieved good results [175]. It may be possible to provide a reference for the timing of conservative treatment of ALDH, the choice of surgical methods, or the possible postoperative complications without relying on large sample size data models in the future. At the same time, with the application of regenerative medicine in orthopaedic-related degenerative diseases, it will also be possible to bring the greatest benefit to such diseases with the least possible trauma in the near future.

Author contributions

Conceptualization, Z.L. and G.X.; software, W.Z. and J.Z.; writing—original draft preparation, J.Z.; writing—review and editing, Z.L. and G.X.; visualization, J.Z., W.Y., W.Q. and W.Z.; project administration, G.X.; funding acquisition, G.X. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by National Natural Science Foundation of China (82204820).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Competing interests

The authors declare no competing interests.