Walker 1

Elijah Walker

Lower Extremities

Professor Zeigler

April 22, 2014

Surgical Review: Lumbar Spinal Fusion

Back pain is an irritating condition that will affect 80% of adults sometime in

their lives (Spine Health.com). Not everyone enjoys having surgery performed on them

but when it is needed, it should be done. The newer spine fusion surgery techniques allow

for improved fusion rates, shorter hospital stays, and a more active and rapid recovery

period. Additionally, better diagnostic tools and better understanding of indications for a

spine fusion are improving outcomes. This essay will further explain background

information, the anatomy, types of injuries and their mechanisms, and surgical

procedures along with the advantages and disadvantages of lumbar spinal fusions.

Before discussing spine fusion surgery techniques it is important to note that very

few people with low back pain actually require surgery. Most individuals can contain

their back pain through a self-directed active physical therapy (exercise) program,

including stretching, strengthening, and a good aerobic conditioning. Unfortunately, for a

small percentage of people, even the most dedicated exercise program is not enough to

alleviate low back pain. In those situations where low back pain continues and limits a

patient's activities, a spine fusion surgery may be considered. Fusion of the lumbar spine

Walker 2

does not create a normal back, nor does it necessarily "fix" a low back. Instead, the

objective of lumbar spine fusion is to stop the motion at a painful motion segment in the

spine, thus minimizing the pain and allowing the patient to increase his or her ability to

function and enjoy everyday activities.

A common type of spine fusion surgery is performed for low back pain. This type

of mechanical lower back pain occurs with increased activities and often times is

associated with degenerative changes in the discs such as degenerative disk disease. At

other times it may be due to slippage of the spine such as  spondylolisthesis. When

considering the indications for lumbar spine fusion surgery, low back pain that lasts for

more than six months is the most general indication. The indications for fusing the low

back occurs primarily in situations where there is a large deformity (such as scoliosis) or,

more commonly, for back pain that does not get better with time or with a non-surgical

treatment. Much care and importance is stressed on our bodies large spine that keeps us

upright.

The spine is formed by 33 vertebral segments and divided into four distinct

portions. The spinal column and the muscles that interact with it control, give support to,

and protect the torso, skull and spinal cord. The portion relevant to this surgical

procedure is the lumbar spine. The lumbar spine provides a more equal balance between

protection of the spinal cord and its available range of motion. The body’s weight is

transmitted primarily along the spinal column by the vertebral bodies, whose size

correlates to the amount of force it transmits. The lumbar vertebrae are required to

transmit and absorb the weight of the entire torso, therefore having the largest vertebrae

and spinal columns. These very distinct vertebrae are situated anterior and makes up the

Walker 3

primary weight-bearing surface. Projecting just posterior from the body of the vertebrae

are the sturdy pedicles that form the anterior portion of the neural arch. The posterior

portion of the arch is composed of the lamina. Projecting laterally, the transverse

processes arise from the laminae and provide an attachment site for the spine’s ligaments

and muscles and increase the muscles’ mechanical leverage (force). The spinous

processes are the furthest posterior projections that act as attachment sites for muscles

and ligaments. The spinal cord passes through the neural arch, posterior, where a tunnel

protects the cord. Facet joints are also present that are formed by two sets of articular

processes. The first process, superior facts, articulate with the second inferior facets of

the vertebrae. These facet joint are on a frontal plane thus allowing lateral flexion but

restricts the rotation of the lumbar region. Flexion and extension of the lumbar region is

allowed on the sagittal plane.

Neurologically the spinal spine contains a network of nerve plexus’.

According to Examination of Orthopedic and Athletic Injuries, a nerve plexus is a

network formed by a consecutive series of spinal nerves that intermix sensory and motor

impulses. A total of 31 pairs of nerve roots exit the spinal column. The lumbar plexus is

formed by the 12th thoracic nerve root and the L1-L5 nerve roots and innervates the

anterior and medial muscles of the thigh and the nerves of the medial leg and foot.

A number of injuries can cause the necessary surgical procedure of a

lumbar spinal fusion. In the case of a spinal fracture, the vertebrae of the spine will need

to be brought back together if possible using a spinal fusion. A slippage between the

vertebrae laterally, medially, anteriorly, or posteriorly and onto the bone below it

(spondylolisthesis) may need spinal fusion surgery in order to hold the vertebrae in a

Walker 4

stable place. Scoliosis is also a spine deformity that can be fixed through a spinal fusion.

Although usually in the cervical region, scoliosis is a condition in which the curvature of

the spine is not straight in an area of the back; usually arched forward or presenting a s-

curve in the spine. Reoccurring disk herniation may need a spinal fusion if not eliminated

after sixth months. Reoccurring herniation may be gradual onset or be a sudden onset due

to certain movements. Although, physical therapy exercise and special treatment of a disk

may relieve and eliminate the herniated disk, thus making the surgery unnecessary. As

explained before, the degeneration of a disk is normal in most Americans with age. The

decreased function of the annulus fibers in the spine may become bad enough as to where

the motion of the torso decreases as well. Rarely, in most cases of disk degeneration

spinal fusion will not be necessary but in the cases where the degeneration inhibits gait,

walking, or movement it will be needed. The last case in which a possible lumbar spine

fusion may be necessary is that of a disk infection. This disk infection is also called

diskitis and although very rare, affects the lumbar region most commonly

(Medscape.com). Diskitis is an inflammation of the vertebral disk space often related to

infection.

The mechanisms of these injuries needing lumbar spine fusion can be alike or

different. In instances of scoliosis, a person will be born with it or it will be detected

before the age of 10 (Ceder’s Sinai.edu). A fracture to the lower spine can be caused by a

couple of mechanisms. Most of the mechanism that will fracture the spine will include a

blow, or a great force, to the spine. As stated in Professor Ziegler’s “Chapter 20: The

Spine” power point, the causes of a lumbar fracture is compression as a result from trunk

hyperflexion or falling from a height or direct blow. Although rare, lumbar dislocation

Walker 5

can happen in these mechanisms as well. Spondylolysis and spondylolosthesis is when

one vertebrae above or below another. The cause of this is the degeneration of the

vertebrae due to congenital weakness (stress fracture results).

Just as fractures have multiple causes so does the herniation of a disk. Here, the

intervertebral disks either shift outward or creates a bubble like projection that causes

pain by putting pressure on a nerve(s). The cause of my personal injury was a herniated

disk. It happened during my senior year of high school in our opening game against the

alumni. I was on a fast break towards the hoop and there was only one other defender

back to guard me. As I powered towards the hoop he ran alongside me. I then went up for

the lay up and I as a rose above the ground so did he. To protect the ball I brought it

down by my side, in the air, twisting my body. We made contact in the air and instead of

contesting my shot the defender fouled me, hard. He threw his whole body into mine and

his arms cam down on top of my neck and I fell to the ground. This abnormal force and

the twisting and forward bend of my body is what caused an abnormal stress to put

pressure on the vertebral disks.

Based on a video from Spine-Health.com, it gives a clear picture of how a spinal

fusion surgery of the lumbar region can be performed to stop the motion at a painful

vertebral segment; which in turn should decrease the back pain from degenerative disk

disease or spondylolisthesis. During the procedure, the surgeon permanently joins two or

more vertebrae in the spine. The vertebrae will grow together to from a single, solid bone.

Spinal fusion is commonly performed in the neck and lower back to correct common

injuries or chronic injuries as discussed before. In preparation for the procedure the

patient is positioned and general anesthesia is administered. The surgeon creates an

Walker 6

incision to aces the lumbar spine. The surgeon removes the lamina, the protrusion of the

rear of the vertebra, which covers the nerve roots. Removing the lamina creates more

space for the nerve roots to. Next, the surgeon clears any bone or debris that may be

pressing against the nerve roots; this relieves pressure and pain. The surgeon will then

place bone grafts against the vertebrae that may be taken from the patient’s own body,

typically, from the pelvis. Then, the surgeon inserts hardware (four screws placed in a

square pattern) to hold the vertebrae together. During this process the surgeon will use

screws and rods or plates to create a metal-like backbone. Usually, two rods are placed

through the screws vertically to support either side of the vertebrae. When the procedure

is complete, the incision is closed and bandaged. The patient may be placed in a back

brace to restrict movement of the spine and will be able to leave the hospital after two or

three days. As the spine heals, the bone grafts will fuse with the bone of the vertebrae to

create a solid, stable mass of bone with continued support of the rods and screws.

Aside from the technique described above there is new technique to perform

spinal fusion called minimally invasive lumbar spinal fusion. Minimally invasive lumbar

spinal fusion is similar to traditional lumbar spinal fusion, but it uses smaller incisions

and causes less damage to the surrounding tissues during surgery. As with traditional

lumbar spinal fusion, there are many specific techniques available to try to fuse the

vertebrae together using minimally invasive techniques. This can be done through the

abdomen, from the back, from the side, or with any combination of these. Fusion with

screws and rods can be performed through the back using several 1-2 inch incisions. In

these cases a series of increasingly larger dilators (hollow tubes with solid inserts) are

inserted through the incisions to help spread the muscles apart. Once the muscles have

Walker 7

been moved away, the screws and rods can be placed through the dilator tubes. The major

advantage of all of these minimally invasive techniques is that there is less damage

caused to the surrounding tissues. Unfortunately, in traditional spinal surgery it is

necessary to cut through muscles and move them out of the way in order to reach the

spine. This can cause a large amount of pain following surgery, and it can lengthen the

recovery time. Instead of cutting and moving muscles, the minimally invasive techniques

can more gently spread through the muscles to allow access to the spine. This is much

less painful for the patient, and it does not require as long of a recovery period for the

muscle to heal. Another benefit of less muscle damage is less blood loss and thus a

reduced need for blood transfusions using the minimally invasive techniques. There is

often less need for narcotic pain medications following this form of surgery, and a shorter

hospital stay (Medicine Net.com). As with any new technique, one of the major

disadvantages is the additional time needed to perform the procedure. While a surgeon

may be very comfortable with the traditional surgical fusion techniques, it will take time

to be able to achieve the same outcome using these new methods. Surgeons with more

experience can now perform lumbar spinal fusion in equal or even less time than with the

traditional techniques but not all surgeons perform these techniques. Because this is a

relatively new technique, many insurance companies consider this to be an

investigational surgery and do not provide insurance coverage for it.

To end my story of my herniated disk I fortunately did not need surgery or a

lumbar fusion. Instead, I was out of the basketball season for 5 months doing strenuous

physical therapy in order to relive the inflammation and pain in my back. I was able to

finish off the last 2 ½ months of basketball with an 85% healthy back. Although I do

Walker 8

have pain in the back to this day, it is only rare and slight pain that can be alleviated

though stretches and core strength. Spinal lumbar fusion is a surgical procedure that may

be needed due to multiple injuries such as my herniated disk. This surgery that involves

fusing two vertebrae together is neither easy or pain free. The result is a solid portion of

the spine coated with hardware and unable to be flexed. In some instances it is necessary

to have the procedure done buy in most cases it is not even needed.