Disc herniation resorption is well documented: a lumbar disc herniation can shrink, and sometimes disappear, without surgery. However, it does not happen at the same pace in every patient. So which herniations resorb early?
A prospective study by Hornung and colleagues found three baseline features that predicted early resorption [1]. This research summary explains the study, the three predictors and what they mean for your patients.
How common is disc herniation resorption?
In fact, resorption is not rare. In a systematic review, Chiu and colleagues calculated how often each type of herniation regresses without surgery [2]:
| Type of herniation | Spontaneous regression |
|---|---|
| Sequestration | 96% |
| Extrusion | 70% |
| Protrusion | 41% |
| Bulging | 13% |
Moreover, the herniation resolved completely in 43% of sequestrations and 15% of extrusions [2].
Similarly, a meta-analysis of 11 cohort studies by Zhong and colleagues put the overall rate of spontaneous resorption at 66.66% [3]. Indeed, even giant herniations can resorb. In a series of 409 patients with giant herniations, 320 were treated without surgery [4]. Of these, 189 patients (59.06%) had more than 30% resorption of the herniation.
Resorption also takes time. In the same series, 40.74% of the resorptions happened within 6 months and 26.98% between 6 and 12 months [4]. The remaining 32.28% took longer than a year.
The study: who resorbs early?
Above all, the timing matters in practice. According to most guidelines, surgery may become an option if a herniation remains symptomatic after 3 months and conservative management fails [1]. Hornung and colleagues therefore asked which patients show disc herniation resorption within those first 3 months [1].
For this purpose, they followed 93 consecutive patients with acute symptomatic lumbar disc herniation at a single center. The mean age was 48.7 years. Lumbar MRI was repeated about every 3 months for one year, and all patients were managed in the same way. Resorption within 3 months counted as early, and resorption after 3 months counted as late. In the end, the early group had 23 patients and the late group 67 [1]. In other words, early resorption occurred in 24.7% of patients.
Notably, all patients in the study had resorbed their herniation within one year [5]. The same research group describes its approach as inflammation-preserving treatment [6]. Specifically, in a report on 90 patients, it used no anti-inflammatory drugs and no steroids. Instead, patients received gabapentin for leg pain and 12 sessions of acupuncture. All 90 patients had resorption within one year, after 4.4 months on average, and none needed surgery [6].
The 3 predictors of early resorption
The authors collected demographic data, herniation features and many MRI findings at baseline. Then they built a prediction model. Three baseline features predicted early disc herniation resorption best [1]:
- A greater herniated volume
- A greater sacral slope
- A greater posterior height of the L4 vertebral body
Key finding
In this study, a larger herniation was a predictor of early resorption, not a barrier to it [1].
1. Greater herniated volume
Overall, this finding fits the wider literature. Ma and colleagues also reported that resorption is more likely when more disc material protrudes into the spinal canal [4]. Likewise, sequestrations and extrusions regress far more often than bulges [2].
In particular, one explanation involves the blood supply. A large herniation that breaks through the annulus fibrosus or the posterior longitudinal ligament reaches the circulation in the epidural space [5]. As a result, inflammation, new blood vessels and macrophages can start to break the material down [5].
2. Greater sacral slope
The second predictor is the sacral slope, the angle between the upper surface of the sacrum and the horizontal. Shen and colleagues summarize the proposed reason: a greater sacral slope may reduce the pressure on the disc and favor resorption [5]. However, the evidence is mixed. Dai and colleagues studied 67 patients with disc extrusion in a retrospective study [7]. Before treatment, sacral slope did not differ between patients whose herniation resorbed and those whose did not. So treat this predictor with caution until more studies confirm it.
3. Greater L4 posterior vertebral height
By contrast, the third predictor is the hardest to interpret. A recent systematic review lists it among the predictors, but it offers no mechanism [5]. For now, therefore, it is best seen as a statistical marker rather than a target for treatment.
Inflammation: friend or foe?
Disc herniation resorption seems to depend on inflammation. The disc normally has no blood supply, so its nucleus is hidden from the immune system [5]. Once it breaks through, however, it triggers an immune response, new blood vessel growth and macrophage activity [5].
This, in turn, raises a clinical question. Anti-inflammatory drugs and steroids relieve symptoms because they block inflammation [5]. Could they also slow resorption? The evidence so far is limited. For instance, in rabbits, high-dose steroids suppressed the replacement of grafted disc tissue. On the other hand, epidural steroid injections in patients relieved symptoms without affecting resorption [5]. Shen and colleagues therefore suggest inflammation-preserving treatment under close observation for patients whose symptoms are mild or tolerable [5]. Medication, of course, remains the physician’s decision.
What this means for physiotherapists
First, a large herniation on MRI is not automatically bad news. In this study, larger herniations were more likely to resorb early [1]. You can use this to reassure a patient who is worried about the size of the herniation on the scan.
Second, resorption takes time, and the timing varies. For example, only about a quarter of patients resorbed within 3 months [1]. Furthermore, in the series of giant herniations, about one third of resorptions took longer than a year [4]. So set expectations for months, not weeks.
Third, the decision to wait depends on safety. Accordingly, conservative treatment is preferred only in the absence of progressive nerve damage or cauda equina syndrome [4,5]. Screen for these signs at every visit and refer at once if they appear.
Finally, the authors propose their risk profile as a way to support clinical decisions and to manage patient expectations [1].
Limitations
Still, keep the limits of this evidence in mind. For one thing, Hornung and colleagues studied 93 patients at a single center [1]. Moreover, a recent systematic review points to a lack of high-quality prospective studies on the predictors of disc herniation resorption [5]. The three predictors therefore need confirmation in other groups of patients before they guide treatment.
Key points
- Disc herniation resorption is common: about two thirds of herniations resorb without surgery, and sequestrations do so most often.
- In a prospective study of 93 patients, about a quarter resorbed their herniation within 3 months.
- A greater herniated volume, a greater sacral slope and a greater L4 posterior vertebral height predicted early resorption.
- Larger herniations may resorb more readily because they reach the epidural blood supply.
- The sacral slope finding is not consistent across studies, and the L4 finding has no clear explanation yet.
- Conservative treatment is an option only without progressive nerve damage or signs of cauda equina syndrome.
References
- Hornung AL, Barajas JN, Rudisill SS, et al. Prediction of lumbar disc herniation resorption in symptomatic patients: a prospective, multi-imaging and clinical phenotype study. Spine J. 2023;23(2):247-260. doi:10.1016/j.spinee.2022.10.003
- Chiu CC, Chuang TY, Chang KH, Wu CH, Lin PW, Hsu WY. The probability of spontaneous regression of lumbar herniated disc: a systematic review. Clin Rehabil. 2015;29(2):184-195. doi:10.1177/0269215514540919
- Zhong M, Liu JT, Jiang H, et al. Incidence of spontaneous resorption of lumbar disc herniation: a meta-analysis. Pain Physician. 2017;20(1):E45-E52. PMID: 28072796
- Ma Z, Yu P, Jiang H, et al. Conservative treatment for giant lumbar disc herniation: clinical study in 409 cases. Pain Physician. 2021;24(5):E639-E648. PMID: 34323452
- Shen X, Dai F, Li Z, et al. Predictive factors for resorption in lumbar disc herniation: a systematic review. J Inflamm Res. 2026;19:559719. doi:10.2147/JIR.S559719
- Albert HB, Sayari AJ, Barajas JN, et al. The impact of novel inflammation-preserving treatment towards lumbar disc herniation resorption in symptomatic patients: a prospective, multi-imaging and clinical outcomes study. Eur Spine J. 2024;33(3):964-973. doi:10.1007/s00586-023-08064-x
- Dai GG, Wang F, Liu L, et al. Sagittal balance parameters correlate with resorption of the lumbar disc extrusion: results of a retrospective study [in Chinese]. Sichuan Da Xue Xue Bao Yi Xue Ban. 2020;51(4):533-539. doi:10.12182/20200760205
