Spondylosis:

The following article on degenerative conditions of the spine has been written for the General Practice/Family Physician community, and for nursing and paramedical staff and medical students.

Keywords: Cauda equina syndrome; Cervical disc; Cervical myelopathy; Cervical radiculopathy; Cervical stenosis; Degenerative spinal disease; Disc herniation; Foraminal stenosis; Lumbar disc; Lumbar radiculopathy; Lumbar stenosis; Sciatica; Spinal stenosis. Anatomical models, medical imaging and operative photographs also included.

Introduction

Spondylosis is a common condition in the Community-at-large. The term refers to a degenerative condition of the spine, typically the result of chronic "wear and tear" of the spine's tissues (discs, ligaments, bones, surrounding tendons). As a result, spondylosis most commonly affects persons over the age of 50, but sometimes younger people present with the condition. The process is akin to a degenerative but not inflammatory "arthritis" of the spine, and typically it occurs over a period of years before becoming a substantial problem for an individual. An accident or other traumatic injury/event may cause a person with underlying spondylosis to suddenly require urgent medical attention.

How does spondylosis present?

The common presenting symptoms are (typically one or more of these):

Local pain in the neck or back
Radiating sharp or electrical pain along the shoulder and down the arm, or sciatica (pain from the buttock down the leg)
Numbness in parts of one or more limbs
Cramping discomfort in one or more groups of limb muscles
Pins and needles (paraesthesiae) sensation along a limb
Development of pain (usually in both legs) during walking, that limits the ability to walk (neuroclaudication)

Less common but more concerning (CLINICAL "RED FLAG") symptoms are:

Numbness around the groin (perineal) and back passage (perianal) regions
New baldder or bowel dysfunction, such as inability or impairment in passing urine (urinary retention), new constipation, or frank incontinence (loss of control of bladder or bowel; i.e., urinary or foecal incontinence)
Inability to use the hands for fine coordination tasks
Subjective weakness in the limb muscles (e.g., foot drop)
Inability to walk steadily with recurrent tripping/falls owing to impaired sensation in the feet (sensory ataxia)
Rapid progression of symptoms
Severe pain in one area of the spine, upon even minimal movements, raises the possibility of a "pathological" fracture (this arises from diseased bone, structurally weakened by osteoporosis - more common, by infection/osteomyelitis - uncommon, or by tumour - uncommon). Sometimes, an abnormal amount of joint movement/slippage (spondylolisthesis) with mechanical instability can also present this way.

Pathogenesis (mechanism) of spondylosis

The body is just a biological machine, and the spine is a key "inner scaffold-like" structure that supports this machine. Risk factors for early spondylosis are: Long-term repetitive movements (e.g., occupation- or contact sports-related "repetitive strain", or a very "manually intense" lifestyle - ongoing substantial bending, lifting, pushing, twisting..) involving the spine, an overweight (obese) frame, smoking, and in some (rare) instances a family history of early spinal degenerative or rheumatological conditions can contribute to the development and acceleration of spondylosis. In rare instances, a birth defect in the spine known as a "pars defect" can cause slippage (spondylolisthesis) between two adjacent spinal bones (vertebrae), especially in the lower spine between L4-L5 or L5-S1. A motor vehicle or sports-related accident, or an injury from a simple fall, can unmask an underlying spondylosis. Note: Among its other toxic and frequently lethal effects on the body, tobacco smoking causes rapid degeneration of the spinal tissues, with accelerated arthritis- Here, the spine of a 35 year old smoker might radiologically appear (and to the patient eventually feel) like that of a 70 year old person; and in time it becomes apparent that smokers tend to look a lot older than their actual age (the same thing is happening on the inside, including the spine and other joints).

Spondylosis is associated with one or more of the following structural changes in the spine:

Loss of intervertebral disc fluid and height, degeneration (dessication) of disc tissue
Protrusion/herniation of a disc
Bony overgrowth around the edges of vertebral bodies (osteophytes)
Overgrowth of soft tissues around the spine (ligamentous hypertrophy)
Overgrowth and/or cystic change within joints of the spine (facet hypertrophy; synovial cyst formation)

These structural changes can lead to compressional injury of the nerve-tissue of the spinal cord (central stenosis) or the nerve roots that eminate from it at exit-windows called foramina (foraminal stenosis), or may be part of a local inflammatory/degenerative arthritis of the spine. Either way, spine-related pain and other symptoms mentioned above can result from such changes.

Figure 1 (above): Spinal anatomy. Lumbar spinal vertebral bones. CE = Cauda Equina; FJ = Facet Joint; FJS = Facet Joint Surface; IVD= InterVertebral disc; L = Lamina; NRF = Nerve Root at the intervertebral Foramen; SP = Spinous Processs; TP = Transverse Process; VB = Vertebral Body. The surgical opening from this (posterior approach) involves making a window in the lamina (L) part of the spinal bone (blue/red circle above right).

Figure 2 (above): Spinal anatomy. Lumbar vertebra (left) and herniated lumbar disc (right). CE = Cauda Equina; FJ = Facet Joint; FJS = Facet Joint Surface; HLD (NP) = Herniated Lumbar Disc's soft inner pulp or Nucleus Pulposus compressing a nerve root of the cauda equina; IVD= Intervertebral disc; IVD (AF) = InterVertebral Disc's thick outer rind or Annulus Fibrosus; L = Lamina; NRF = Nerve Root at the intervertebral Foramen; P = Pedicle; SP = Spinous Processs; TP = Transverse Process; VB = Vertebral Body. The surgical opening from this (posterior approach) involves making a window in the lamina (L) part of the spinal bone (blue/red circle above right).

Assessing the Severity of Spondylosis

Clinically

The medical history should take into consideration the duration of the symptoms, any progression in the symptoms and time-course (temporal changes), the presence of any of the clinical red flags mentioned above, the contribution of any risk factors (see above).
The physical examination should be systematic and include general inspection (antalgic features at rest or during transfers from sitting to standing to couch etc?, any focal wasting?), assessment of gait (footdrop?, sensory ataxia?), tone, power, reflexes (focally diminished? or...any of these: bilateral hyperreflexia, ankle clonus, Hoffman sign, Babinski sign). Check for focal (quite localised) pain and tenderness that may suggest a fracture, joint inflammation, or a significant soft tissue injury there. Check sensation (including perianal and perineal when indicated); check anal sphincter tone when indicated. Check the range of motion of the neck and lumbosacral spine; look for special signs: straight-leg raise (SLR), foraminal (lateral flexion with axial loading) compression-induced radiculopathy, and Lhermitte's phenomenon. Remember, in certain presentations there may be secondary gain or a functional overlay. Reflex changes are good objective measures. Distraction during the physical examination can be useful in ascertaining the presence of functional overlay.

Radiologically

One or more of the following may be appropriate: plain x-rays of the c-spine or lumbar spine; lateral flexion-extension views of the c-spine or lumbar spine; CT of the spine; MRI of the spine; nerve conduction/EMG. Radionucleide bone scan (pathologic fracture with inflammation, focal infection/ostemyelitis).
Any of the following changes may be found: Loss of disc height, loss of disc water content, anterolisthesis (forward slippage), posterolisthesis (backward slippage), facet and ligamentous hypertrophy, disc herniation (broad-based, or focal herniation with or without a free fragment migration), central versus foraminal stenosis at one or more spinal levels, T2 signal change within the cord, compression of the cauda equina, synovial cyst,...
On an MRI, Type 2 Modic changes correspond to spondylosis: T1 hyperintensity AND T2 iso- or slight hyper-intensity.

Complications Associated With Spondylosis

Radiculopathy: From nerve root compression: Pain, sensorimotor and hyporeflexic changes (lower motor neuron signs) that follow the specific distribution of a nerve root dermatome/myotome. There should not be upper motor neuron (UMN) signs, and there should not be any bowel or bladder dysfunction.
Myelopathy: From spinal cord compression: (UMN signs) Multiextremity weakness, limb hyperreflexia, hypertonia (spasticity), pathological reflexes (Babinski, Hoffman, ankle clonus), Lhermitte's sign, bowel and bladder dysfunction (retention or retention-with-overflow, or frank incontinence).
Cauda equina syndrome (CES): Usually three or more of the following features: Lower extremity (LE) pain; LE weakness; LE numbness; impaired bowel and bladder function; diminished LE reflexes; decreased sphincter tone; saddle anaesthesia. Note that CES, especially if there is bilaterality and rapid progression of symptoms, is an indication for emergent neurosurgical intervention.
Failed back syndrome (FBS): Here, repeated interventions (see below) for spondylosis have provided no lasting relief, and the patient is left with pain and/or disability from the progressive arthritis and/or its treatment. Smoking substantially increases the risk of FBS, through poor healing and ongoing accelerated arthritis. In the unfortunate setting of FBS, referral to a professional pain management team may be undertaken.

Treatment Options

Conservative: Rest may be appropriate (particularly avoiding any aggravating causes such as lifting, bending, pushing, etc.), combined with use of: mild analgesics and anti-inflammatory medications; local balms and heat therapy; physiotherapy and hydrotherapy. Such measures are usually not appropriate if there are red flag symptoms.
Local injections: A trial of one or two local nerve root or epidural injections may be indicated in the absence of any red flag symptoms.
Surgery: Depending on the site and nature of the structural problem...
- Laminectomy with nerve root decompression (rhizolysis), and/or discectomy: Here, an incision is made in the midline posteriorly (e.g., back of neck or lower back), and via that path, a window is made in part of one or more adjacent spinal bones ("laminae"). The compressive soft tissue elements ("ligamentum flavum" and "mesial facet") are then removed and thus the spaces around the spinal and nerve sacs are surgically "cleaned out" or "decompressed". If the intervertebral disc is also contributing to the compression, the "offending" part of the disc is removed at the same time. In a simple laminectomy/discectomy, there is no requirement for any metal instrumentation to be used.
..

Above - Multilevel decompressive laminectomy: The above two intraoperative photos show, in the left shot, a build up of soft tissues (yellow ligament and "facet" joint) causing compression of the spinal cord in the neck. In the right shot: after successful removal of the compressive soft tissues using a combination of fine-tip drills and rongeurs. The spinal cord (housed in its leathery "dural sheath" or "thecal sac" seen here) is now free and pulsatile again.
- Anterior cervical discectomy and fusion (ACDF): Here, an anterior (front-side) neck incision is made, and the surgeon accesses the cervical spine (neck bones) from in front. The offending disc(s) or disc-bone (osteophyte) complex(es) is/are removed from in front, and a metal or polymer spacer is put in place of the removed disc(s), and usually supplemented by insertion and securing of a titanium plate with screws from in front, to keep that part of the cervical spine solidly fused and stable.
Above - Single level anterior cervical discectomy and fusion (ACDF): Intraoperative photographs showing, on the left: placement of a PEEK cage filled with hydroxyapatite bone cement. In the middle: angled anchoring titanium screws of length 11mm (1.1 cm, less than half-inch) being placed in the cage and from there into the adjacent bone. On the right: Intraoperative X-ray confirms good placement of the angulated screws (top left and bottom left of this image) with the cage in the centre (radio-opaque parallel metal indicators seen). This instrumentation contributes to providing good alignment and stablity.
- Complex spinal procedure: requiring the use titanium rods, screws, disc spacers, etc. as part of the reconstructive/stabilization part of the procedure. This is usually the case if there has been a significant traumatic injury to the spine, or if there is pre-existing slippage (spondylolisthesis) or if repeated/more extensive surgery is required at the same spinal level as a previous operation (re-do surgery). Any time one part of the spine is surgically fused with metal, the immediately adjacent parts of the spine can in some instances degenerate a little more rapidly leading to "adjacent segment spondylosis" and failed back syndrome.

When to Refer to a Neurosurgeon

Elective (routine/non-urgent): For persistence of any of the common symptoms listed above
Urgent: In the presence of any of the red flag symptoms listed above

Figure 3 (above): Spinal stenosis. Axial T2 MRI. The left image (NORMAL) shows the nerve roots of the cauda equina (red asterisk). They lie free and uncompressed, bathed in cerebrospinal fluid (white regions around these nerve root/dots). The right image (ABNORMAL) shows the compressed nerve roots of the cauda equina (red asterisk). Here, overgrown facet joints (FJ) and the neighbouring (dark band) ligamentum flavum ligament under the lamina (L) and a broad-based intervertebral disc bulge (IVD) are all contributing to the "central" and "biforaminal"/"lateral recess" pattern of stenosis seen here. The surgeon needs to carry out a laminectomy (red/blue circle), making a window in the lamina bone (L) here, followed by a clearing out the compressive soft tissues around the spinal tissue (thecal) sac and nerve roots (rhizolysis).

Figure 4 (above): Herniated lumbar disc causing lumbar radiculopathy/sciatica. Axial T2 MRI. The left and right images show some nerve roots of the cauda equina (red asterisk) compressed by the herniated lumbar disc (HLD). The surgeon needs to carry out a one-sided (hemi) laminectomy (red/blue circle), making a window in the lamina (L) and the inner (medial) part of the adjacent facet joint (FJ) here, followed by a clearing out the compressive soft tissues (rhizolysis) and local discectomy.

Figure 5 (above): Herniated lumbar disc causing cauda equina syndrome. Axial (lef) and sagittal (top right) T2 MRI. The nerve roots of the cauda equina (coloured circle, top right) are severely compressed by the herniated lumbar disc (yellow arrows in left and top right images). This is a neurosurgical emergency as the patient is at risk of permanent and severe leg weakness and numbness with loss of bowel and bladder control. Laminectomy and discectomy were carried out, the multiple disc fragments are shown in the bottom right image. The patient made an excellent recovery.

Figure 6 (above): Two different causes of cervical myelopathy. Sagittal T2 MRI. In the left image, multiple herniated cervical discs (black protrusions at blue arrow heads) infront of the cervical cord, and multiple areas of ligament overgrowth (black protrusions) behind the cervical cord are shown within the region of the large red circle. Note how these protrusions indent (efface) the cord, and there is loss of the normal (T2-bright) surrounding cerebrospinal fluid signal at these levels. In the right image, a relatively rare condition known as ossification of the posterior longitudinal ligament (OPLL; black band at tips of blue arrow heads) is causing severe compression of a long segment of the cervical cord. The cord is damaged by this compression (white signal within the small red circle). Both of these patients underwent successful urgent surgery to decompress their stenoses.

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