Laminectomy

The body’s spinal column enables each of us to walk upright. It is the central support for the upper body and carries the weight of head, chest and arms. The vertebra of the lumbar portion of the spine carries the majority of this weight. The constant pressure from this weight, even when simply sitting in a chair, contributes to problems associated with the back and spine.

Back pain ranks second only to headaches as the most frequent location of pain. Each year more than 65 million Americans experience low back pain and 80% of us will have significant back pain at some time during our lives. Many, perhaps most, will have more than one episode and some will go on to develop back pain that bothers them virtually every day of their lives. At times, this pain will be due to abnormal pressures on the spinal cord or the nerves emerging from it. This pain may be from a variety of causes; it may also be chronic in nature or occur as an emergency. Whatever the reason, should the hard, protective bone surrounding the spinal cord need to be disrupted or removed, it is a laminectomy that is called for (Chicken Noodle Soup for Low Back Pain, 2003) (Hellman, 2004).

Laminectomy is a term used to describe a range of surgical interventions on the spine in which the paired wing shaped areas of bone that surround the spinal cord itself are disrupted or removed. The lamina are the locked doors of the spine. In order to access the spinal canal, spinal cord, or the nerves coming from the cord through intricately designed foramen, the doors of the lamina must be breached. Often, when the term laminectomy is used, people immediately think of the lower back. This is misleading. Lamina occurs from top to bottom of the spine, and a laminectomy can involve any area or region of the spinal cord protective cover.

The spine is a complex 3-dimensional structure capable of flexion, extension, lateral bending, and rotation. The total range of motion is the sum of many limited movements that occur between the interlocking chain of bony units that make up the vertebra. Each individual vertebra connects to the adjacent vertebra either above or below by a trio of joints. One joint resides at the front (anteriorly) and two at the back (posteriorly) of the vertebral unit or vertebral body. The joint pad at the front is called the intervertebral disc and is a common cause of surgical pathology. The joints at the back of the vertebral body straddle the midline and are known as facet joints (Venas, 2004).

Pads of tough cartilage, called intervertebral discs, separate the bony vertebra of the spinal column from one another. These joint pads act like shock absorbers during activity, preventing individual vertebra from rubbing against one another.

(NIH Publication No. 04–5327 National Institute of Arthritis and Musculoskeletal and Skin Diseases, November 2004)

In addition to bony structures and joints, there are numerous strong muscles and ligaments crucial for support as well as the initiation and control of movements. One of the more important ligaments is the ligamentum flavum. This yellow hued band connects and supports by bridging between adjacent vertebra. It is also involved in spinal pathology and back pain, as it tends to thicken with age leading to compression of nerves.

The spinal cord sits inside a bone tunnel called the spinal canal, located in the posterior half of each vertebra. The band of the ligamentum flavum lines the back half of this bone tube that is formed by wing shaped pieces of bone called lamina. At each vertebral level, a pair of lamina unites, forming the distinctive spinous process felt in the midline of the back, through the skin. Nerve tissue passes-through at regular levels on each side of the spinal canal comprising nerve passages known as intervertebral foramina, or foramen. Each foramen allows one nerve bundle to exit into the soft tissues of the body. At its end, the spinal cord terminates at the lower border of the first lumbar vertebra, evolving into a horsetail of nerves, the cauda equina.

(NIH Publication No. 04–5327 National Institute of Arthritis and Musculoskeletal and Skin Diseases, November 2004)

In the neck, there are seven levels of lamina, and procedures involving disruption of these bones in the spine in this region of the cervical spine are referred to generically as a cervical laminectomy. To clarify the location, lamina are named by the number of the vertebra associated with them, from the top down, as well as the region. This means that surgery on the fourth spinal lamina in the cervical region would be referred to as a C4 laminectomy. In the chest, or thoracic region of the spine, are twelve levels of lamina and in the lumbar region are five levels of lamina. The fused bones of the sacrum are considered one unit when describing lamina by location. This means that surgery involving the bone in this area is simply referred to as a sacral laminectomy.

A laminectomy can involve one or multiple vertebra. For example, a surgery that removes part or all of the spinal cord protective bone from lumbar vertebra 2, 3 and 4 is referred to as a L2-4 laminectomy. A procedure involving lamina in two spinal regions, such as thoracic lamina 12 through lumbar lamina 3 is a T12-L3 laminectomy.

There are two general reasons for the need to remove a portion of the protective bone surrounding the spinal cord. The first reason is pain or numbness due to pressure on the spinal cord or the nerves emerging from it. This is caused by conditions like spinal stenosis, a slipped intervertebral disc, or arthritic changes of the spine. The success rate for laminectomy surgery has been described as favorable, with 70 to 80% of patients receiving significant improvement in their function as well as relief from pain and other symptoms. Interestingly, relief from leg pain is reported to occur much more frequently and to a greater extent than the relief of lower back pain (Ullrich, 2003).

Secondly, the protective lamina bone must be disturbed whenever access to the spinal cord itself is required. Such as when a tumor located within the spinal canal requires removal.

As people age, the spine goes through some natural changes. In a condition referred to as disk degeneration or degenerative spine the gelatin-like centers of intervertebral discs begin to dry out, causing them to compress or flatten. This, in turn leads to narrowing of the foramen, the openings through which nerves exit from the spine. A constricted foramen will increase pressure, which may cause pain or impairment of nerve tissue.

A herniated intervertebral disk may warrant a laminectomy. Normal wear, tear or strain may cause these disks to bulge or rupture (herniated). When a disk herniates, parts of it protrude or bulge from their normal position between vertebra. At times, such a fragment of the herniated disk can put pressure on an adjacent nerve resulting in pain, numbness, tingling or weakness.

Disk material pressing on spinal nerve

In spinal stenosis, a narrowing of the spinal canal or of the foramina (the plural of foramen) through which nerves exit the spinal canal occurs. This narrowing can result from the development of bony growths (bone spurs) where disks have compressed and are allowing vertebra to rub against each other. Whenever thickening of bone or ligaments occurs, pinching of nerves or the spinal cord may result. However, many people have narrowing of these openings with little or no symptoms. Therefore, surgery is only considered when symptoms significantly affect a person’s quality of life.

Fractures to the spine can occur when direct injury occurs anywhere along the bones of the vertebral column. Spinal fractures may require surgery if the spine is unstable or the spinal cord or nerve roots are compressed. Osteoporosis can weaken vertebra, causing them to fracture or collapse with minimal or no trauma. In osteoporosis, physicians tend to reserve invasive procedures such as spinal surgeries for when other treatment measures have failed.

Surgery to remove either a tumor or an infectious abscess may require a laminectomy to access the spinal cord. Laminectomies are also an essential part of the surgical repair of spinal deformities. Scoliosis (curvature of the spine), kyphosis (a humpback deformity) and spondylolisthesis (forward slippage of a segment of the spine) all may require surgery if they progress to a point that compromises quality of life, are painful, or are causing nerve compression.

Some laminectomies are emergency procedures, perhaps for a problem causing rapid paralysis of the legs or arms. Others are carried out as planned procedures for slow deterioration in the limbs, or for pain. When a nerve is compromised by pressure or injury either in the spinal cord or at the points of pass-through of the spinal cord, symptoms of this problem will be specific to what impulses that nerve conducts, or fails to conduct. Pressure on the nerves exiting from the foramen of the cervical vertebra does not cause bladder problems, but a low thoracic or lumbar nerve compromise might. Indications for surgical intervention tend to start out very broad and general; gaining specificity as the symptoms lead closer to the true cause. General signs and symptoms that may indicate a laminectomy start with such things as:

• Pain that radiates primarily down one leg (sciatica) or arm
• Coldness, tingling and burning in an extremity
• Numbness, weakness or tingling more in one arm or leg then the opposing
• Loss of control over a bodily function, such as impotency, bladder or bowel control

Careful evaluation of the patient is important. Comorbid medical conditions must be isolated and sorted out. This requires appropriate consultation before considering surgical intervention. A thorough neurological examination is essential. Certain signs, such as extremity pain and hyperextension of the back in the standing patient, can be a strong indication of disease process. Watch also for muscle weakness that is more apparent after exercise. With or without the presence of such weakness, consider obtaining a current EMG study.

Recumbent x-rays of the spine are helpful to see if there are any abnormalities of the bones, such as fractures or subluxation, dislocation of a vertebra. Standing and dynamic x-rays may also be useful in detecting spinal instability patterns. Next, it is common to order a myelogram. In a myelogram, imaging dye is injected into the space around the spinal cord. This allows visualization of anything pressing on it. Many patients and some healthcare workers associate these dyes with unpleasant side effects such as intense back pain and headaches. This use to be the case; however, modern dyes have reduced this problem so that it is uncommon to have difficulties of this nature.

Computerized tomography (CT) scanning of the spine is often combined with myelograms, and magnetic resonance (MRI) scanning can give good information on the spinal cord and its surrounding bones. As its availability grows, MRI scanning is rapidly becoming the main test for spinal problems.

Some tests, which are useful for specific suspicions, include selective nerve root blocks utilizing an image intensifier. This is especially helpful to confirm a specific nerve roots that may be causing pain. Cystometrograms are useful in determining bladder function and narrowing down the extent of nerve impairment. Doppler and radiographic dye studies on the lower extremities may also be of use in those with vascular claudication in addition to neurogenic claudication.

Laminectomies are always performed under general anesthetic. Though a laminectomy is often done for access during another procedure, certain elements are typically involved in all laminectomies. The patient is positioned face down. A surgeon’s preference may have knees bent forward in a kneeling type posture to provide greater extension of the spinal vertebra, especially with low back procedures. Specialty surgical tables, such as the Jackson table are frequently used to decrease abdominal pressure on the vena cava. The Jackson table is also preferred as it allows room for imaging equipment such as C-Arms to be used in both the anterior/posterior (AP) and lateral plane. An incision is made in the middle of the back directly over the area. In traditional laminectomies, this incision ranges from two to five inches in length. Newer procedures are being developed that dramatically decrease the incision size. The incision is then deepened to the muscles and the ligaments are spread outwards, using crank type tissue retractors, to expose the spinous process and lamina. Crank retractors are necessary, as the tissues require retraction away from the operative area for a prolonged period. The retractors must be released periodically in order to allow blood flow through the paraspinal muscles (Orthopaedic Care Textbook, Accessed 2005), (Ullrich, 2003).

The correct lamina level is confirmed by either counting from a fixed point, or taking an x-ray. It is then re-confirmed, to avoid error. Having exposed the lamina, the bone is nibbled away using a variety of bone cutters, depending on surgeon’s preference. Generally, an instrument known as a kerrison rongeur is used. This is a tool designed to take little bites off bone. The amount of lamina removed depends on the purpose. For example, little is removed in an uncomplicated repair of a slipped disc operation, while a great deal of bone will be taken to decompress the spine for arthritis or tumor excision.

Removal of the lamina, (laminectomy) unroofs the spinal canal and leads to a marked enlargement of the space available for nerves and spinal cord. Occasionally, so much of the lamina must be removed that there are concerns about the strength of the remaining spine. In these situations, metal rods or bone grafts from the hip are inserted to provide support. Once the purpose of the surgery is achieved, the bleeding is stopped, muscles are sewn up and the skin closed. Either sutures or staples may close the skin, according to the surgeon's choice.

One interesting variation on the laminectomy is the Laminoplasty. This is often used when the spinal canal becomes narrowed, with the spinal cord and nerves compressed, such as in spinal stenosis. Laminoplasty refers to opening up the space of the spinal canal by splitting open the lamina. Paired lamina are like a set of locked double doors positioned over the spinal canal. The spinous process is first removed, then the central portion of the lamina is split and each lamina (right and left) is hinged open. Once opened, the lamina is kept open through bone struts, sutures or other techniques. Laminoplasties are most often performed in the cervical spine when several levels of the spine are involved. It is considered a good alternative to anterior cervical fusion in carefully selected patients (Index of Common Surgical Procedures and Techniques, Accessed 2005).

A foraminectomy is a laminectomy of the foramen, the natural passage or tunnel present between the vertebra of the spine through which a nerve root exits from the spinal canal on its path to a specific tissue or organ. When the foramen becomes narrowed, the nerve can become irritated or dysfunctional, which is often seen in conditions such as spinal stenosis, lateral disc herniations, and facet arthritis. Bone must then be removed from the portion of the lamina surrounding this opening, creating more room for the nerve (Index of Common Surgical Procedures and Techniques, Accessed 2005).

Following laminectomy, nursing care should include frequent repositioning, vigorous pulmonary toileting, and deep venous thrombosis (DVT) prophylaxis. Sequential compression devices (SCD), which decrease venous stasis in the legs, should be employed. In most cases, patients are encouraged to be out of bed the first postoperative day. Bracing devices such as a neck brace for cervical or a chair-back brace for low back surgeries are utilized when walking. Residual drains are removed within 48 hours. Antibiotics are typically continued for 48 hours post procedure. Discharge home with home healthcare follow up follows three to five days of hospitalization. With procedures that are more complex or with patients with comorbid conditions two to three weeks of supervised care in a short-term rehabilitation setting is typical (Ullrich, 2003).

 Patients are encouraged to be as active as possible following discharge from the hospital. Some will be able to drive within a month after surgery. Those with a preoperative neurological deficit may take longer. Most patients can discard their braces within the first 6 to 12 weeks. Formal physical therapy varies with specific procedures, but is rarely necessary in laminectomy patients once they are walking independently. Swimming or gentle water exercise is helpful postoperatively, after approval by a physician. The use of a stationary bicycle and treadmill is often encouraged. Be sure to encourage compliance with the specific plan of care established by the surgeon (Orthopaedic Care Textbook, 2005).

Infections can occur following any surgery of the spine, especially following a long procedure with a complicated instrumentation placement. Following elective laminectomy procedures, the rate of significant infection is reported to be around one percent.

Superficial infections should be opened and debrided. The wound is then packed open or closed using retention sutures. Appropriate antibiotics are used, starting with coverage against gram-positive coccus and adjusting according to culture results (Venas, 2004), (Ullrich, 2003).

The incidence of nerve root injury during laminectomy has been reported to be around 1 in 1000 procedures. This is considered quite low, as nerve injury, including weakness, numbness, or paralysis due to trauma to nerve tissues that could possibly occur during the procedure. Tears in the fibrous tissue that covers the spinal cord and the nerve near the spinal cord also occur from one to three percent of the time. When they do, a second surgery to repair the tear in the dura is sometimes required (Ullrich, 2003).

Deep vein thrombosis, DVT, is a potential complication in patients with spinal surgery. Prophylaxis precautions are varied; but, usually include subcutaneous heparin, sequential compression stockings, and/or elastic hose placed on the lower extremities. Patients who develop DVT require aggressive treatment with anticoagulation. If the risk for systemic anticoagulation is prohibitive, options include thrombectomy or a cava vein filter (Venas, 2004).

Ogilvie syndrome, which includes an adynamic Ileus, is an infrequent complication following laminectomy procedures. This syndrome is primarily characterized by nausea, vomiting, diarrhea, and severe abdominal distension. Preventive measures include minimizing bed rest, returning to ambulation as early as possible, and limiting the use of narcotics. Early recognition and treatment are essential to reduce morbidity and mortality. Initial treatment includes cessation of oral intake, nasogastric suction, insertion of rectal tubes, and cessation of narcotics (Venas, 2004).

Significant bowel or bladder incontinence complications are reported to occur in a 1 out of 10,000. Neurologic distention of the bladder can lead to autonomic dysreflexia, impairment of bladder sensation, detrusor hyperreflexia, and sphincter dyssynergia. All of which can lead to renal damage from hydronephrosis or vesicourethral reflux. These complications are decreased with indwelling Foley catheters immediately post operatively (Ullrich, 2003).

Chicken Noodle Soup for Low Back Pain. Updated November 18, 2003. Back.com. Accessed February 8, 2005.

Index of Common Surgical Procedures and Techniques. Accessed 2005. OthoSpine.com. http://www.orthospine.com. Accessed February 9, 2005.

Laminectomy. May 20, 2002. Reviewed May 2004. Better Health Channel. http://www.betterhealth.vic.gov.au. Accessed February 9, 2005.

Hellman, R. January 20, 2004. Technology Tomorrow: Greater Baltimore Medical Center Offers New Center, New Hope. Greater Baltimore Medical Center. http://www.gbmc.org/mediarelations/News_Coverage/dynesys. Accessed February 9, 2005.

Ullrich, P. December 18, 2003. Lumbar Laminectomy (Open Decompression). http://www.spine-health.com/topics/surg/overview/lumbar/lumb04.html. Accessed February 11, 2005.

Venas, F. July 8, 2004. Lumbar Spine Fractures and Dislocations. E-Medicine.com. http://www.emedicine.com/orthoped/topic176.htm. Accessed February 9, 2005.

Orthopaedic Care Textbook. Accessed 2005. OrthopaedicCareNet. Journal of the Southern Orthopaedic Association. http://www.orthotextbook.net. Accessed February 9, 2005.