Which nerve root is affected by lumbar disc herniation, IVF stenosis, or degenerative spondylolisthesis?

It is important to know which spinal pathology can create which radicular symptoms. Often one must correlate imaging with the patient’s symptoms, in order to determine if imaging findings are responsible for symptoms or if they are merely incidental findings. Knowing which nerve roots are affected by which spinal conditions also helps formulate a differential diagnosis and helps with treatment approaches. To help with this, I created a summary table of common conditions, intervertebral foramen stenosis (IVF), lumbar disc herniation (LDH), and degenerative spondylolisthesis (DSPL).

	L4	L5	S1	Ref.
L4-5 IVF	100%	--	--
L4-5 LDH	7%	94%	10%	1
L4-5 DSPL	sometimes	Uni/bi	--
L5-S1 IVF	--	100%	--
L5-S1 LDH	--	29%	81%	1
L5-S1 DSPL	--	sometimes	Uni/bi

Lower lumbar disc herniations affect a single nerve root in 60% of cases and two nerve roots in 40% of cases (considering that radiculopathy is present).2 Degenerative lumbar spondylolisthesis affects a single nerve root in only 10% of cases, two nerve roots in 19% of cases, and three or more nerve roots in 71% of cases, being bilateral in the same percentage of cases.3 Intervertebral foraminal stenosis affects the exiting nerve root and thus usually only affects one nerve root4, except for cases with conjoined nerve roots, which is rare.5

1. Janardhana, A. P., Rajagopal, S. R. & Kamath, A. Correlation between clinical features and magnetic resonance imaging findings in lumbar disc prolapse. Indian J. Orthop. 44, 263 (2010).

2. Kortelainen, P., Puranen, J., Koivisto, E., Lähde, S. & others. Symptoms and signs of sciatica and their relation to the localization of the lumbar disc herniation. Spine 10, 88 (1985).

3. Epstein, N. E., Epstein, J. A., Carras, R. & Lavine, L. S. Degenerative spondylolisthesis with an intact neural arch: a review of 60 cases with an analysis of clinical findings and the development of surgical management. Neurosurgery 13, 555–561 (1983).

4. Jenis, L. G. & An, H. S. Spine update: lumbar foraminal stenosis. Spine 25, 389–394 (2000).

5. Taghipour, M., Razmkon, A. & Hosseini, K. Conjoined Lumbosacral Nerve Roots: Analysis of Cases Diagnosed Intraoperatively. J. Spinal Disord. 22, 413–416 (2009).

The Prognosis and Natural History of Sciatica

          Sciatica as caused by lumbar disc herniation is very common. Between 12.2 and 43% of people will develop sciatica at some point in their life.¹ A major question about sciatica is, how long does it last? Also, what are the factors that delay recovery or indicate a poor prognosis? What are the factors that speed recovery or indicate a good prognosis? Not all cases of sciatica have the same cause. Some cases will last weeks or months, and others longer. There is a wide range of severity with sciatica as well. While the majority will resolve with conservative measures, some cases benefit from early surgery. This article discusses the general factors that impact recovery in patients that opt for either nonsurgical or surgical treatment of sciatica. The scope of this article pertains to degenerative conditions of the lumbar spine and the information is most applicable to lumbar disc herniation and discogenic sciatica.

 

Quick facts – Prognosis of Sciatica

·         The majority of recovery of sciatica occurs within the first three months and then slowly after that14 ·         About 1/3rd of patients with sciatica recover within two weeks and about ¾ recover within three months (with rest and pain medication)9 ·         Up to 23% of patients can have lingering symptoms of sciatica that fluctuate and last 5 years or more10 ·         The fastest healing of lumbar discs occurs within the first two months then slowly after that until 1 year they are mostly healed15 ·         Patients that have a background of vigorous exercise have a better prognosis compared to those that do not exercise2 ·         Early microdiscetomy roughly doubles the speed of recovery from sciatica in comparison to conservative medical care consisting of pain medication, however after 1 year the results are similar17 ·         60% of patients with sciatica benefit from spinal manipulation, and respond as well as those who undergo surgery18 ·         If sciatica centralizes with end-range lumbar motions the patient is six times less likely to go to surgery, and has a faster return to work and more rapid reduction in leg pain and disability13

 

Summary of Prognostic Factors

	Good Prognosis	Poor Prognosis
Socio-demographic variables	·   ≥ 10 years of school education2	·   Driving ≥ 2 hours per day3 ·   Heavy labor3,4 ·   Obesity4,5 ·   Presence of a compensation claim2 ·   Smoker6,7
Back pain/sciatica history	·   No previous episodes of sciatica8 ·   Sciatica already improving before visiting a doctor9	·   Baseline VAS leg pain ≥70 out of 10010 ·   Duration of back pain >1 year11 ·   Duration of sciatica >3 months11 ·   Prior episode(s) of sciatica8
Self-reported health status	·   Better baseline general health8 ·   Convinced of return to work in less than 6 months (if on sick leave)2 ·   Fewer subjective health complaints8 ·   Vigorous or regular exercise several times a week including heavy gardening and housework2	·   Fear avoidance beliefs2 ·   Kinesiophobia7,11 ·   Light or no exercise2 ·   More comorbid subjective health complaints11 ·   Psychosomatic problems3 ·   Worrying and health anxiety2
Clinical findings	·   Centralization of pain with end-range lumbar motions12,13	·   > 8 tender points on examination2 ·   Bragard’s test6 ·   Crossed straight leg raise6 ·   Diffuse tenderness2 ·   Disturbed sensation14 ·   Reduced tendon reflex11
Diagnostic test findings	·   Sequestration or extrusion of disc material, with greater degree of migration15,16	·   Disc protrusion or less migration of disc material15,16

  

 

Adapted from data published by Lequin, Grovle, Peul, Haugen, Skytte, as reference below, and Weinstein, James N., et al. "Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial." Jama 296.20 (2006): 2441-2450.

 

Historical Note

The first person to give a thorough prognosis for sciatica was Hippocrates, around 400 BC. In his text “Predictions and Prognostics” he writes:

With respect to sciatica, the following observations demand attention… In age… the disease will be very obstinate… to continue for a year at least... In young people, the disease is to the full as painful… forty days will usually bring it to a termination… ¹⁹

 

Exercise

          People that have a history of exercising vigorously or several times per week, including heavy gardening and housework, recover faster from sciatica than those that did not exercise leading up to the onset of sciatica.² Exercise does not prevent sciatica, however patients that are fit and healthy have a better prognosis. This is likely related to core musculature strength, which contributes to stability of the spine. A significant relationship exists between the size of the psoas muscle and disc herniation and sciatica.²⁰ The multifidus, erector spinae, and quadratus lumborum are atrophied in cases of chronic low back pain and/or sciatica.²¹ Whether the muscles are atrophied as a result of disc pathology or are a cause of it is another question. Another angle to look at this is the physiology of the intervertebral disc which has a poor blood supply and thus obtains its nutrition via osmosis with movement of the spine. In my clinical experience, I have seen some of the fastest recoveries of sciatica in athletes who are overtraining or placing too much stress on the low back. After taking a break from training there is often a fast rebound in these patients.

Physiotherapy

          Centralization is a term used to describe the reduction of pain or other symptoms in an extremity so that pain moves from distal to more proximal. If the symptoms of sciatica centralize in response to end-range loading of the lumbar spine (see image for an example), a faster recovery is expected.^12,13 Most patients with sciatica caused by disc herniation (about 85%) are capable of experiencing the centralization phenomenon. This is why it is important for patients with sciatica to find a doctor or therapist that is familiar with this approach. 

Kinesiophobia

          Kinesiophobia is the fear of movement, and has been associated with a worse prognosis for sciatica.^7,11 People with sciatica may impede their own recovery by avoiding normal activities of daily living, because they expect that doing these things will cause pain. As stated above, the contrary is generally true, that specific types of exercise and movement are beneficial in speeding the recovery from sciatica. In fact, bed rest has been found to be not particularly helpful for sciatica, and is no more effective than “watchful waiting” or advice to stay active.^22,23 Patients with sciatica should see a qualified practitioner to determine if they are candidates for exercise and rehabilitation for their sciatica. In my experience, I usually do not recommend total rest, and when I do, it is for a short period of time.

 

Unnecessary Medical Tests

          It has been shown that simply having Magnetic Resonance Imaging (MRI) in cases of radiculopathy or sciatica increases the duration of disability and medical expenses, compared to not having an MRI.²⁴ Imaging should only be performed when there is a necessity or a clear indication for it. This is because imaging may reveal pathology of the spine that does not contribute to the patient’s sciatica. Lumbar disc herniations are commonly found in asymptomatic people²⁵, the identification of which could present a problem for both the clinician and patient. MRI findings may cause anxiety for patients which contributes to disability and medical spending. John E. Sarno writes about this in “Healing Back Pain, The Mind-Body Connection”:

If the low back pain is accompanied by pain in the leg, or sciatica, there is even greater concern an apprehension, for this raises the spectre of the herniated disc and the possibility of surgery. In this media-dominated age very few people have not heard of herniated discs and the idea arouses great anxiety, resulting in greater pain. If, in the course of medical investigation, imaging studies show a herniation, the apprehension is multiplied even further.²⁶

          In my clinical experience, I have seen that patients who have undergone MRI tend to remember that they herniated a disc, even after being asymptomatic for years. Often, in the event that low back pain recurs, they may ascribe their pain to the herniated disc and think that it has herniated again or never healed. On the other hand, patients who have had sciatica in the past and have not undergone MRI tend to not think in this way. It seems that a side effect of imaging is that it can reinforce the memory of pain.

 

1.  Konstantinou, K. & Dunn, K. M. Sciatica: Review of Epidemiological Studies and Prevalence Estimates. Spine 33, 2464–2472 (2008).

2.  Jensen, O. K., Nielsen, C. V. & Stengaard-Pedersen, K. One-year prognosis in sick-listed low back pain patients with and without radiculopathy. Prognostic factors influencing pain and disability. Spine J. 10, 659–675 (2010).

3.  Tubach, F., Beauté, J. & Leclerc, A. Natural history and prognostic indicators of sciatica. J. Clin. Epidemiol. 57, 174–179 (2004).

4.  Bejia, I., Younes, M., Zrour, S., Touzi, M. & Bergaoui, N. Factors predicting outcomes of mechanical sciatica: a review of 1092 cases. Joint Bone Spine 71, 567–571 (2004).

5.  Rihn, J. A. et al. The Influence of Obesity on the Outcome of Treatment of Lumbar Disc Herniation: Analysis of the Spine Patient Outcomes Research Trial (SPORT). J. Bone Jt. Surg. Am. 95, 1 (2013).

6.  Peul, W. C., Brand, R., Thomeer, R. T. & Koes, B. W. Influence of gender and other prognostic factors on outcome of sciatica. Pain 138, 180–191 (2008).

7.  Haugen, A. J. et al. Prognostic factors for non-success in patients with sciatica and disc herniation. BMC Musculoskelet. Disord. 13, 183 (2012).

8.  Grøvle, L. et al. Prognostic factors for return to work in patients with sciatica. Spine J. 13, 1849–1857 (2013).

9.  Vroomen, P. C. A. J., Krom, M. C. T. F. M. de & Knottnerus, J. A. Predicting the outcome of sciatica at short-term follow-up. Br. J. Gen. Pract. 52, 119–123 (2002).

10. Lequin, M. B. et al. Surgery versus prolonged conservative treatment for sciatica: 5-year results of a randomised controlled trial. BMJ Open 3, e002534–e002534 (2013).

11. Haugen, A. J. et al. Estimates of success in patients with sciatica due to lumbar disc herniation depend upon outcome measure. Eur. Spine J. 20, 1669–1675 (2011).

12. Albert, H. B., Hauge, E. & Manniche, C. Centralization in patients with sciatica: are pain responses to repeated movement and positioning associated with outcome or types of disc lesions? Eur. Spine J. 21, 630–636 (2012).

13. Skytte, L. P., May, S. & Petersen, P. Centralization: Its Prognostic Value in Patients With Referred Symptoms and Sciatica. Spine June 1 2005 30, (2005).

14. Grøvle, L., Haugen, A. J., Natvig, B., Brox, J. I. & Grotle, M. The prognosis of self-reported paresthesia and weakness in disc-related sciatica. Eur. Spine J. 22, 2488–2495 (2013).

15. Autio, R. A. et al. Determinants of spontaneous resorption of intervertebral disc herniations. Spine 31, 1247–1252 (2006).

16. Takada, E., Takahashi, M. & Shimada, K. Natural history of lumbar disc hernia with radicular leg pain: Spontaneous MRI changes of the herniated mass and correlation with clinical outcome. J. Orthop. Surg. Hong Kong 9, 1 (2001).

17. De Schepper, E. I. T. et al. Diagnosis of Lumbar Spinal Stenosis: An Updated Systematic Review of the Accuracy of Diagnostic Tests. Spine April 15 2013 38, (2013).

18. McMorland, G., Suter, E., Casha, S., du Plessis, S. J. & Hurlbert, R. J. Manipulation or Microdiskectomy for Sciatica? A Prospective Randomized Clinical Study. J. Manipulative Physiol. Ther. 33, 576–584 (2010).

19. Hippocrates, Coxe, J. R. & Galen. The writings of Hippocrates and Galen. (Philadelphia : Lindsay and Blakiston, 1846). at <http://archive.org/details/56811050R.nlm.nih.gov>

20. Dangaria, T. R. & Naesh, O. Changes in Cross-Sectional Area of Psoas Major Muscle in Unilateral Sciatica Caused by Disc Herniation. Spine 23, 928–931 (1998).

21. Ploumis, A. et al. Ipsilateral atrophy of paraspinal and psoas muscle in unilateral back pain patients with monosegmental degenerative disc disease. Br. J. Radiol. 84, 709–713 (2011).

22. Hagen, K. are B., Jamtvedt, G., Hilde, G. & Winnem, M. F. The updated Cochrane review of bed rest for low back pain and sciatica. Spine 30, 542–546 (2005).

23. Vroomen, P. C., de Krom, M. C., Wilmink, J. T., Kester, A. D. & Knottnerus, J. A. Lack of effectiveness of bed rest for sciatica. N. Engl. J. Med. 340, 418–423 (1999).

24. Webster, B. S., Bauer, A. Z., Choi, Y., Cifuentes, M. & Pransky, G. S. Iatrogenic consequences of early magnetic resonance imaging in acute, work-related, disabling low back pain. Spine 38, 1939–1946 (2013).

25. Boden, S., Davis, D., Dina, T., Patronas, N. & Wiesel, S. Abnormal magnetic-resonance scans of the lumbar spine. Asymptomatic Subj. Prospect. Investig. J Bone Jt. Surg Am 72, 403–408 (1990).

26. Sarno, J. E. Healing Back Pain: The Mind-Body Connection. (Grand Central Life & Style, 2010).