Nucleus Pulposus Herniation


Article Author:
Franco De Cicco


Article Editor:
Gaston Camino Willhuber


Editors In Chief:
Dustin Constant
Donald Kushner


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Kyle Blair
Trevor Nezwek
Radia Jamil
Erin Hughes
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Navid Mahabadi
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Daniyal Ameen
Altif Muneeb
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes
Komal Shaheen
Sandeep Sekhon


Updated:
6/1/2019 2:40:17 PM

Introduction

Nucleus pulposus herniation is the most common cause of sciatic pain and one of the most common indications for spine surgery worldwide.[1] This condition presents as a displacement of the nucleus pulposus beyond the intervertebral disc space. 

The disc anatomy consists of two main structures, the nucleus pulposus (NP) and the annulus fibrosus (AF).

The nucleus pulposus is composed of water, type II collagen, chondrocyte-like cells, and proteoglycans. This unique composite allows the NP to be elastic, flexible under stress forces and to absorb compression.[2]

The composition of the AF is mainly concentric layers of collagen type I fibers,[3] forming a fibrous tissue with helical disposition surrounding the NP, this structure is denser in the anterior part and is attached to the vertebral body by Sharpey fibers.

Etiology

Disc herniation and disc degeneration are associated terms, being nucleus pulposus herniation a possible evolution from a degenerative disc. Disc degeneration is usually associated with loss of proteoglycans.[4] Multiple factors influence the degenerative process such as genetic, mechanical, and behavioral.[5][6]

The intervertebral disc is a structure that provides flexibility and transmits loads through the spine. Mechanical load is important in maintaining a healthy IVD by generating signals to cells that regulate proper matrix homeostasis.[7][8] On the other hand, prolonged exposure to hypo or hyper loading correlates with disc degeneration induction.[9][10]

Epidemiology

The estimated prevalence of disc herniation is approximately 1 to 3%. The highest observed incidence is between 30 to 50 years, and it is more frequent in men than in women (Ratio 2 to 1).

Pathophysiology

Disc herniation is a consequence of degenerative changes in the annulus; those changes are age-related adaptive modifications in the disc structure that encompass desiccation, fissures, disc narrowing, mucinous degeneration, intradiscal gas (vacuum), osteophytes, inflammatory changes, and subchondral sclerosis. Annulus fissures predispose to a weakness, which allows disc material to bulge or migrate outside the annulus margins.

Histopathology

Nucleus pulposus herniation results from a failure in the annulus fibrosis integrity, making the content of the nucleus to protrude into the neural canal, the intervertebral foramen (foraminal) or lateral to the foramen (extraforaminal). Nucleus pulposus protrusion is the less severe scenario of disc herniation, due to partial rupture of the annulus fibrosis (See figure 1), when the annulus structure becomes completely disrupted the nucleus content may extrude outside the disc space and in some cases a fragment of nucleus pulposus may migrate (sequestration).

Another way to differentiate protrusion from extrusion is related to the shape of the displaced material. A protrusion is when the greatest distance between the limits of the disc material outside the disc space is less than the distance between the limits of the base of that disc material outside the disc space. The base is the width of disc material at the outer margin of the disc space. Extrusion is present when, in at least one plane, the distance between the limits of the disc material beyond the disc space exceeds the distance between the limits of the base of the disc material beyond the disc space. 

Another type of disc herniation is when disc material migrates in craniocaudal direction through a gap between the endplate and the disc making a space within the vertebral body (intravertebral disc herniation) better know as Schmorl nodes.[11]

The integrity of the annulus fibrosus has to be compromised to develop a nucleus pulposus herniation. The loss of annulus fibrosus integrity may be present in different forms, such as radial, transverse, or concentric fissures. These types of fissures are observable in the early stages of disc degeneration. One important kind of annulus fissure can be observed in T2-weighted MRI and is called high-intensity zone (HIZ), this changes denote the presence of liquid within an annular fissure and correlates with acute disc annular tear or fissure.[12]

History and Physical

Proper understanding of anatomical zones and vertebral level is essential to interpret the clinical manifestations secondary to a disc herniation. Wiltse proposed these anatomical zones, based on the following landmarks: medial border of the articular facet, lateral, upper and medial borders of the pedicles, coronal and sagittal planes at the center of the disc. On the axial plane, these landmarks determine the central zone, the subarticular zone (lateral recess), foraminal, and extraforaminal zones. On the sagittal plane, the levels are termed as follows: The supra pedicular level, the pedicular level, the infrapedicular level, and the disc level. The correct knowledge of anatomy and relationship between nerve roots and disc herniation allows the proper understanding of common clinical findings associated with this problem.

There are two main mechanisms to explain radicular pain secondary to a nucleus pulposus herniation: Mechanical compression and inflammatory reaction. Clinical symptoms may vary according to several factors such as the location of the herniation (level), neural compression, and evolution. Nucleus pulposus herniation can produce low back pain; however, the primary clinical manifestation is radiculopathy, which is mainly manifested by radiating pain and sensitive changes that encompass nerve distribution. Additionally, reflexes assessment (decreased reflex) may help to identify the compromised nerve root.

We summarize the anatomy, motor function, sensitive distribution, and reflex of the most commons nerve roots involved in cervical and lumbosacral nucleus pulposus herniation:

Cervical:

  • C5 nerve root: Exits between C4 and C5 foramina, innervates deltoids and biceps (with C6), sensory distribution: lateral arm (axillary nerve) and is assessed with biceps reflex.
  • C6 nerve root: Exits between C5 and C6 foramina, innervates biceps (with C5) and wrist extensors, sensory distribution: lateral forearm (musculocutaneous nerve), assessed with brachioradialis reflex.
  • C7 nerve root: Exits between C6 and C7 foramina, innervates triceps, wrist flexors, and finger extensors, sensory distribution: middle finger, assessed with triceps reflex.
  • C8 nerve root: Exits between C7 and T1 foramina, innervates interosseus muscles and finger flexors, sensory distribution: ring and little fingers and distal half of the forearm (ulnar side), no reflex.

Lumbosacral:

  • L1 nerve root: Exits between L1 and L2 foramina, innervates iliopsoas muscle, sensory distribution: upper third thigh, assessed with the cremasteric reflex (male).
  • L2 nerve root: Exits between L2 and L3 foramina, innervates iliopsoas muscle, hip adductor, and quadriceps, sensory distribution: middle third thigh, no reflex.
  • L3 nerve root: Exits between L3 and L4 foramina, innervates iliopsoas muscle, hip adductor, and quadriceps, sensory distribution: lower third thigh, no reflex.
  • L4 nerve root: Exits between L4 and L5 foramina, innervates quadriceps and tibialis anterior, sensory distribution: anterior knee, medial side of the leg, assessed with patellar reflex.
  • L5 nerve root: Exits between L5 and S1 foramina, innervates extensor hallucis longus, extensor digitorum longus, and brevis, and gluteus medius, sensory distribution: anterior leg, lateral leg, and dorsum of the foot, no reflex.
  • S1 nerve root: Exits between S1 and S2 foramina, innervates gastrocnemius, soleus, and gluteus maximus, sensitive distribution: posterior thigh, plantar region, assessed with Achilles reflex.

Cervical and thoracic disc herniation can also exhibit symptoms of myelopathy such as spasticity, clumsiness, wide-based gate, and weakness, on physical examination hyperreflexia is the most important sign. The Lhermitte sign is the presence of an electric shock-like sensation towards the back and lower extremities, especially by flexing the neck.[13][14] Bowel and bladder dysfunction may indicate poor prognosis.

Evaluation

In the presence of low back pain without symptoms of radiculopathy, there is no need to request studies as most of the patients improve in a couple of weeks, 4-week follow-up is the usual timeframe.[15]

X-ray is the initial workup study when there is a strong suspicion of a specific cause of cervical or back pain (fracture, infection, tumor) or in the presence of red flags (fever, age more than 50, recent trauma, pain at night or rest, unexplained weight loss, progressive motor or sensory deficit, saddle anesthesia, history of cancer or osteoporosis, failure to improve after six weeks of conservative treatment). Anteroposterior and lateral x-ray is helpful to assess fracture, bony deformity, decreased intervertebral height, osteophytes, spondylolisthesis, and facet joint osteoarthritis.

MRI is the recommended diagnostic imaging in cases of severe or progressive neurologic deficits, suspicion of an underlying condition such as infection, fracture, cauda equina syndrome, spinal cord compression. In cases of radiculopathy, most of the cases improve with conservative treatment, and MRI is indicated in those cases with significant pain or neurologic deficits.[16]

CT myelogram is the imaging option in patients with contraindications to MRI.

CT scan is not usually requested in nucleus pulposus herniation. However, it can be helpful in some cases when there is a suspicion of calcified disc herniation (thoracic disc herniation has a 30 to 70% rate of calcification) which is more challenging especially when surgery is a consideration.

Treatment / Management

Therapeutic management of nucleus pulposus herniation encompasses conservative and surgical treatment. Conservative treatment is the main strategy due to the natural history of nucleus pulposus herniation, with good response to pain treatment or nerve root steroid injection as well as some cases of spontaneous regression.[17][18]

Some patients will not benefit from conservative treatment and will require surgery to decompress the nerve involved. Classical surgical indications are motor deficit, cauda equina syndrome, and persistent pain after conservative treatment.

In cervical disc herniation, there is no evidence of effectiveness for conservative treatment compared with surgery [Level I].[19] Different randomized controlled trials (RTC) have compared conservative versus surgical treatment in lumbar disc herniation, observing faster pain relief and recovery in the early surgery groups, however, similar outcomes in the long term (one or two years) were found.[20][21] In another trial, carefully selected patients who underwent surgery for lumbar disc herniation achieved greater improvement compared to nonoperative treated patients at eight years follow up [Level II].[22]

Differential Diagnosis

Nucleus pulposus herniation is the most common cause of radicular pain in the lumbar spine and the second most common cause in the cervical spine after degenerative spondylosis; however, other conditions in the differential diagnosis should be considered such as:

  • Neurinoma/schwannoma
  • Facet joint/ligamentum flavum hypertrophy
  • Facet joint cyst
  • Spondylolisthesis
  • Conjoined nerve root

Prognosis

The majority of patients suffering from nucleus pulposus herniation experience symptoms resolution without surgery.[23] Conservative treatment is effective, and patients usually experience symptom relief after a couple of weeks. However, some cases do not improve with conservative treatment and may require more invasive therapies such as nerve root steroid injection or even surgery.

The presence of myelopathy in cases of central nucleus pulposus herniation in the cervical or thoracic region is an indication for surgery, especially in the setting of symptoms progression. 

Complications

Complications associated with nucleus pulposus herniation can result from the compression effect on the nerve root in severe cases resulting in motor deficit, in the cervical and thoracic spine there is also a risk of spinal cord compression in severe cases. These complications are relatively uncommon but should be considered and properly treated to avoid a permanent neurological deficit.

Cauda equina syndrome is another complication that results from lumbosacral nerve roots compression with possible bowel or bladder dysfunction. It is a rarely occurring condition (less than 1%). However, it is considered an absolute indication for acute surgical resolution, and early decompression is associated with symptoms improvement.[24]

Deterrence and Patient Education

It is crucial for patients to recognize radicular pain because it can be the result of a nucleus pulposus herniation in the cervical or lumbar spine. It is essential to have a consult after a persistent radiating pain and be examined by a primary care provider. Most of the symptoms usually improve with conservative treatment; only a few cases with severe pain or neurologic deficit may need additional imaging studies and further specialist referral.

Enhancing Healthcare Team Outcomes

Nucleus pulposus herniation is a common complaint among young adults; clinical symptoms such as low back or cervical pain with radicular pain (brachialgia or sciatica) may raise suspicion of a possible nerve root inflammation/compression and further referral to a specialist. In cervical disc herniation, there is no evidence of effectiveness for conservative treatment compared with surgery [Level I], on the other hand, carefully selected patients who underwent surgery for lumbar disc herniation achieved more significant improvement compared to nonoperative treated patients [Level II]. A coordinated effort between the primary care provider, specialty-trained nurses, spine specialists, physical therapists and chiropractors (who may be the patient's first point of contact), communicating across professions, is vital to guide proper management in patients with symptomatic nucleus pulposus herniation [Level V].


  • Image 11039 Not availableImage 11039 Not available
    Contributed by Franco De Cicco MD
Attributed To: Contributed by Franco De Cicco MD

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Nucleus Pulposus Herniation - Questions

Take a quiz of the questions on this article.

Take Quiz
A 48 year old male warehouse worker has a 6 month history of low back pain with radiation down the posterior right leg and associated paresthesias of the lateral right foot. Strength has not been affected. Bladder and bowel function are normal. Which of the following is most likely on exam?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 35-year-old male presents to the clinic with low back and sciatic pain. An MRI shows a right disc protrusion at L5-S1 level. The patient has decreased plantar flexion on the right side, and a positive straight leg raise test. What is the most likely affected nerve root?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient complaining of sciatic pain presents with his recent MRI results. A big sized extrusion is observed at L4-L5 level; in addition, two disc protrusions at L2-L3 and L3-L4 are also reported. Which of the following best describes the difference between a protrusion and an extrusion?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 34-year-old male complains of severe sciatic pain that is not relieved by pain medication. A positive straight leg raise test is observed at 30 degrees on the right side associated with decreased hallux dorsiflexion. What is the most common cause of pain in this case?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient complaining of low back pain and sciatica follows up at the clinic with MRI results which shows a nucleus pulposus herniation at L4-L5. His response has been modest to pain medications and a nerve root steroid injection one week ago. Which of the following is the most accurate statement about the prognosis of the patient's condition?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Nucleus Pulposus Herniation - References

References

Martin BI,Mirza SK,Comstock BA,Gray DT,Kreuter W,Deyo RA, Reoperation rates following lumbar spine surgery and the influence of spinal fusion procedures. Spine. 2007 Feb 1;     [PubMed]
Chen S,Fu P,Wu H,Pei M, Meniscus, articular cartilage and nucleus pulposus: a comparative review of cartilage-like tissues in anatomy, development and function. Cell and tissue research. 2017 Oct;     [PubMed]
He Y,Qiu Y,Zhu F,Zhu Z, Quantitative analysis of types I and II collagen in the disc annulus in adolescent idiopathic scoliosis. Studies in health technology and informatics. 2006;     [PubMed]
Roughley PJ,Alini M,Antoniou J, The role of proteoglycans in aging, degeneration and repair of the intervertebral disc. Biochemical Society transactions. 2002 Nov;     [PubMed]
Hadjipavlou AG,Tzermiadianos MN,Bogduk N,Zindrick MR, The pathophysiology of disc degeneration: a critical review. The Journal of bone and joint surgery. British volume. 2008 Oct;     [PubMed]
Battié MC,Videman T,Kaprio J,Gibbons LE,Gill K,Manninen H,Saarela J,Peltonen L, The Twin Spine Study: contributions to a changing view of disc degeneration. The spine journal : official journal of the North American Spine Society. 2009 Jan-Feb;     [PubMed]
MacLean JJ,Lee CR,Alini M,Iatridis JC, The effects of short-term load duration on anabolic and catabolic gene expression in the rat tail intervertebral disc. Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 2005 Sep;     [PubMed]
MacLean JJ,Lee CR,Grad S,Ito K,Alini M,Iatridis JC, Effects of immobilization and dynamic compression on intervertebral disc cell gene expression in vivo. Spine. 2003 May 15;     [PubMed]
Lotz JC,Chin JR, Intervertebral disc cell death is dependent on the magnitude and duration of spinal loading. Spine. 2000 Jun 15;     [PubMed]
Lotz JC,Colliou OK,Chin JR,Duncan NA,Liebenberg E, Compression-induced degeneration of the intervertebral disc: an in vivo mouse model and finite-element study. Spine. 1998 Dec 1;     [PubMed]
Takahashi K,Miyazaki T,Ohnari H,Takino T,Tomita K, Schmorl's nodes and low-back pain. Analysis of magnetic resonance imaging findings in symptomatic and asymptomatic individuals. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 1995;     [PubMed]
Jha SC,Takata Y,Abe M,Yamashita K,Tezuka F,Sakai T,Higashino K,Nagamachi A,Sairyo K, High intensity zone in lumbar spine and its correlation with disc degeneration. The journal of medical investigation : JMI. 2017;     [PubMed]
Sayegh FE,Kenanidis EI,Papavasiliou KA,Potoupnis ME,Kirkos JM,Kapetanos GA, Efficacy of steroid and nonsteroid caudal epidural injections for low back pain and sciatica: a prospective, randomized, double-blind clinical trial. Spine. 2009 Jun 15;     [PubMed]
Turk O,Antar V,Yaldiz C, Spontaneous regression of herniated nucleus pulposus: The clinical findings of 76 patients. Medicine. 2019 Feb;     [PubMed]
Peul WC,van Houwelingen HC,van den Hout WB,Brand R,Eekhof JA,Tans JT,Thomeer RT,Koes BW, Surgery versus prolonged conservative treatment for sciatica. The New England journal of medicine. 2007 May 31;     [PubMed]
Jacobs WC,van Tulder M,Arts M,Rubinstein SM,van Middelkoop M,Ostelo R,Verhagen A,Koes B,Peul WC, Surgery versus conservative management of sciatica due to a lumbar herniated disc: a systematic review. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2011 Apr;     [PubMed]
Benoist M, The natural history of lumbar disc herniation and radiculopathy. Joint, bone, spine : revue du rhumatisme. 2002 Mar;     [PubMed]
Srikandarajah N,Boissaud-Cooke MA,Clark S,Wilby MJ, Does early surgical decompression in cauda equina syndrome improve bladder outcome? Spine. 2015 Apr 15;     [PubMed]
Siivola SM,Levoska S,Tervonen O,Ilkko E,Vanharanta H,Keinänen-Kiukaanniemi S, MRI changes of cervical spine in asymptomatic and symptomatic young adults. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2002 Aug;     [PubMed]
Uribe JS,Smith WD,Pimenta L,Härtl R,Dakwar E,Modhia UM,Pollock GA,Nagineni V,Smith R,Christian G,Oliveira L,Marchi L,Deviren V, Minimally invasive lateral approach for symptomatic thoracic disc herniation: initial multicenter clinical experience. Journal of neurosurgery. Spine. 2012 Mar;     [PubMed]
Chou R,Qaseem A,Snow V,Casey D,Cross JT Jr,Shekelle P,Owens DK, Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Annals of internal medicine. 2007 Oct 2;     [PubMed]
Lateef H,Patel D, What is the role of imaging in acute low back pain? Current reviews in musculoskeletal medicine. 2009 Jun;     [PubMed]
Gebremariam L,Koes BW,Peul WC,Huisstede BM, Evaluation of treatment effectiveness for the herniated cervical disc: a systematic review. Spine. 2012 Jan 15;     [PubMed]
Lurie JD,Tosteson TD,Tosteson AN,Zhao W,Morgan TS,Abdu WA,Herkowitz H,Weinstein JN, Surgical versus nonoperative treatment for lumbar disc herniation: eight-year results for the spine patient outcomes research trial. Spine. 2014 Jan 1;     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Surgery-Podiatry Cert Medicine. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Surgery-Podiatry Cert Medicine, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Surgery-Podiatry Cert Medicine, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Surgery-Podiatry Cert Medicine. When it is time for the Surgery-Podiatry Cert Medicine board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Surgery-Podiatry Cert Medicine.