Cervical and low back pain and radiculopathy

1. Cervical and low back pain and radiculopathy Jenice Robinson, MD Assistant Professor of Neurology Penn State College of Medicine NBS725 January 12, 2009

2. Learning Objectives: After reviewing the content of the lecture, the student will be able to: 1) Distinguish somatic and radicular neck and low back pain by mechanism of pain and by associated clinical symptoms and signs 2) Describe the anatomy of the ventral and dorsal nerve roots, the location of the cell bodies in the ventral horn and dorsal root ganglia, and the formation of the spinal nerves 3) List common symptoms and signs of cervical and lumbosacral disk herniation causing nerve root compression 4) Draw the anatomy of the nerve roots at the L4-L5 and L5-S1 levels and demonstrate how a disk herniation at these levels may compress the nerve roots 5) Describe diagnostic imaging methods for use to evaluate radicular pain 6) Describe basic treatment of radiculopathy caused by disc herniation 7) List ‘red flags’ in the evaluation of neck and low back pain indicating increased risk for a possible serious underlying cause of the pain

3. Back and neck pain: Very common Up to 50% of working adults have had a back injury in the past year Back symptoms most common cause of disability in patients <45 Neck pain also very common Societal cost of back pain estimated to be > $20 billion dollars per year

4. Somatic pain: Most cervical and low back pain fall into the category of somatic pain Somatic pain arises from the stimulation of A (small myelinated) and C (unmyelinated) nociceptive nerve endings Activation can be chemical via tissue damage Direct mechanical stimulation

5. Pain sensitive structures: Muscles Ligaments

6. Pain sensitive structures: Muscles Ligaments Facet joints (zygapophyseal) Dura mater Intravertebral discs: annulus fibrosis Epidural veins

7. Somatic pain: Aching/expanding pressure Felt locally in area of injury, but also my be referred to other areas Referred to areas innervated by the same spinal cord segment Mechanism is convergence in spinal cord and thalamus Afferents from the primary source of pain converge with afferents from the site of referral

8. Referred pain from stimulation of zygapophyseal joints

9. Somatic pain: Summary Aching/pressure quality Occurs in broad areas reflecting areas of referral from the same spinal segment, severe could radiate to limbs Otherwise known as back strain and etc. Does NOT: Travel in bands Have a lancinating or electric shock quality Have associated neurologic signs on examination

10. Radicular pain: Less common than somatic pain The hallmark of radiculopathy, any pathologic condition affecting the nerve roots Arises from the nerve roots or dorsal root ganglia Herniated disk is by far the most common cause

11. Radicular pain: Inflammation is important as a pain mechanism: Phospholipase A and E, NO, TNF, other pro-inflammatory mediators are released by a herniated disk The dura surrounding the ventral and dorsal nerve root is bathed in this exudate Inflammation or prior injury to nerve root is necessary to cause compression to generate continued pain

12. dura

14. Radicular pain: Lancinating or electric quality Moves in bands and usually radiates down the limbs Associated symptoms of paresthesias are very helpful determining the identity of the involved nerve root better than site of pain Symptoms of weakness and objective findings of sensory loss, weakness and reflex loss may occur

15. Dermatome • Each nerve root supplies cutaneous sensation to a specific area of skin, known as a dermatome Overlaps somewhat, so won’t lose All sensation, but will feel paresthesia

17. Myotome • If radicular pain sever could affect myotome • Each nerve root supplies motor innervation to certain muscles, known as a myotome

18. Types of peripheral nerve injury: Neurapraxia: Segmental loss of myelin coating on nerve root/nerve Weakness, but no atrophy Axonotmesis: Loss of axons and myelin but at least some supporting structures are preserved Weakness and muscle atrophy if severe Neurotmesis: Loss of axons, myelin, and complete disruption of supporting structures (transection) weakness and atrophy

19. Radiculopathy: Summary Pain and paresthesias radiating in the distribution of a nerve root, often associated with sensory loss and paraspinal muscle spasm Sensory loss (often vague or ill defined) Weakness (often subjective, not present, or mild) Reflex loss (may be present or absent)

20. Radiculopathy: Provocative maneuvers Valsalva Cough, laughter, voluntary contraction of abdominal wall muscles, when straining, make radicular pain worse Stretching the involved nerve root—L1S1—sitting worsens, C5C6—abduct arm over head relieves Straight leg raise—L5L6 worsens

21. Reflexes: C5-C6 Biceps C5-C6 Brachioradialis C7 Triceps L3-L4 Quadriceps/patellar S1 Ankle 60s—no ankle jerks—could be normal if on both sides, but if only on one side With pertinent symptoms on that side--significant

22. In the cervical spine: Nerve roots exit above their named vertebral body I.e., C7 exits below C6 and above C7-so lateral disk herniation here gets C7 In the lumbar spine: Spinal cord ends at L1 or L2 Nerve roots travel long distances then exit below their named vertebral body The lumbosacral nerve roots are susceptible to injury at multiple locations T11-L1—anterior horn

23. L4-L5 lateral disk herniation Usually will compress the L5 nerve root L5-S1 lateral disk herniation Usually will compress the S1 nerve root These are the general rules and anatomy to remember for the cervical and lumbosacral spine…

24. But in the LS spine there are exceptions! Nerve roots Large disk herniation, far lateral,

25. Cauda equina and conus medullaris syndromes: Severe radiating pay, L4L5 lvl herniated midline, all nerve roots are pinched

26. Cauda equina and conus medullaris syndromes: Large midline disk herniation can cause symptoms in both legs in the distribution of multiple nerve roots, bilateral, large full bladder Cauda equina syndrome: multiple nerve roots bilaterally are affected below the end of the spinal cord at L1-2 Conus medullaris syndrome: the end of the spinal cord from about T11-L1

27. Cauda equina and conus medullaris syndromes: Both are potentially surgical emergencies depending on the cause Warning signs that one of these may be present are: Rapidly progressive bilateral lower extremity weakness Saddle anesthesia Loss of ability to urinate voluntarily with a large bladder and overflow incontinence Loss of rectal tone

28. Cauda equina and conus medullaris Differentiating the two is difficult, and they may coexist: Cauda equina: More pain, asymmetric at onset, bladder dysfunction not initially as severe Conus medullaris: Often little pain, symmetric at onset, severe bladder dysfunction Key points: Emergent imaging with MRI is essential Make sure to image high enough to see the full conus! To at least T10

29. Summary: Neurologic features of LS radiculopathy

30. Summary: Neurologic features of cervical radiculopathy C7 most common

31. Radiculopathy: Etiology besides herniate disk which is most common Structural Disk (MC) Spondylosis (degenerative changes) Tumor (mass lesion) Abscess Hematoma

32. Radiculopathy: Etiology Non-structural, or infiltrative Tumor (carcinomatous or lymphomatous meningitis) Granulomatous tissue (e.g., sarcoid) Infection (e.g., Lyme disease, herpes zoster, cytomegalovirus, herpes simplex). Acute inflammatory demyelinating neuropathy Infarction Vasculitic neuropathy Diabetic polyradiculopathy

33. Severe radicular pain in All extermities, lime disease White over everything

34. Differential diagnosis of radiculopathy: I do not expect you to know these next two slides in detail, however, please be familiar with the concepts Radiculopathy always must be distinguished from other peripheral nerve or plexus problems Root lesion (radiculopathy) vs plexus lesion C5/6 vs Upper trunk C8 vs Lower trunk L3/4 vs Lumbar plexus L5/S1 vs Sacral plexus

35. Differential diagnosis of radiculopathy: Root lesion (radiculopathy) vs entrapment neuropathy C6/7 vs carpal tunnel syndrome (med. n. at wrist) C8 vs ulnar neuropathy at the elbow L3/4 vs femoral neuropathy L5 vs peroneal n. at the fibular neck Bilateral L5-S1 radiculopathy vs early peripheral polyneuropathy Could be appropriate by EMG/NSV

36. Imaging: Indications Somatic back and neck pain: Often not helpful and not indicated unless the patient has risk factors for a serious underlying cause of back pain Incidence of spine abnormalities such as disk bulges/minor herniations is about 25-50% in asymptomatic people! Current techniques are not helpful in identifying the source of the somatic pain

37. Imaging: Indications Imaging is appropriate in the following patients: Trauma Risk factors for serious underlying etiology Symptoms present for >4 weeks Neurologic deficit

38. Imaging: Modalities X-rays: most useful in trauma to exclude fracture, not sensitive for nerve root or spinal cord pathology CT: most useful study for bony anatomy MRI: most useful study for imaging disk, nerve root and spinal cord pathology Contrast is used if patient has had prior spine surgery in the affected area b/c can light up scar tissue, or if tumor, infection, or other inflammatory etiology is suspected CT myelogram, CT/w dye injected into spine: in patients who cannot obtain MRI, often the best study for imaging the nerve roots of a selected area

39. ‘Red flags’: Risk factors for a possible serious underlying cause of low back or neck pain include (b/c <1% of ppl with neck/back pain have underlying etiology except these): Age >50 years Prior diagnosis of cancer Lung, breast, colon, prostate, lymphoma, renal cancers especially History of serious medical condition (i.e., AIDS, TB, artificial heart valve, severe COPD, etc.) Use of glucocorticosteroids Chronic/frequent pulmonary or urinary infections History of intravenous drug use Duration of pain > 1 month Urinary or bowel urgency or incontinence Risk factors for a possible serious underlying cause of low back pain additionally include: Pain is worsened or not improved by lying down Signs associated with a potentially serious etiology of low back or neck pain: Unexplained weight loss Percussion tenderness over the spine Rapidly progressive neurologic deficit

40. Treatment of radiculopathy: Natural history of lumbosacral and cervical radiculopathy: Up to 75% spontaneously improve Length of time required for improvement may be several weeks or up to years! If there is a progressive neurologic deficit or intractable pain, surgical referral is appropriate Otherwise, most patients can avoid surgery

41. Empiric treatment of radiculopathy: Medications: Pain control with NSAIDS and narcotic medications as necessary Short course of corticosteroids in selected patients; justification is to decrease inflammation around the nerve root

42. Empiric treatment of radiculopathy: Gentle physical therapy (mobilization and stretching) Bed rest TENS unit, heating pads, ultrasound, gentle massage Traction for the cervical spine Epidural steroid injections for the LS spine Risks are higher in cervical spine Transforaminal steroid injections for the LS spine