Cefazolin

As much as 80% of the US population will be affected by back pain at some time during their lives. (1) Some of the causes of low back pain are

* aging (ie, normal wear and tear on the vertebrae and discs);

* injury or trauma;

* infection; and

* tumor.

According to injury statistics from the US Bureau of Labor Statistics, there were 303,750 work-related back injuries in 2003. (2) The aging process itself can lead to back pain that may require treatment and surgery, and because people today are living longer, the number of patients with back pain increases every year. Members of the Baby Boom generation will be the largest population of older adults in history who may require joint and back treatment or surgery. (3)

Factors leading to back pain at any age are related to the anatomy of the lumbar spine that consists of five vertebrae located in the lowest portion of the spine. The natural shape of the lumbar spine is a lordotic curve that looks like a backwards C. The location of the lumbar vertebrae makes them more likely to be injured because the major work of the back (eg, lifting, carrying) is accomplished using the lumbar spine. This results in injuries involving disc herniation. Movement of discs or spondylosis also will occur more frequently at this level than at other levels.

Conservative treatment for back pain may include rest, use of anti-inflammatory medications, and physical therapy. After a patient has undergone conservative treatment for at least six months with poor results, he or she may decide to pursue surgical intervention for pain. Spinal fusion is one of the most commonly performed procedures for degenerative disorders of the lumbar spine. (4)

The surgeon determines whether to perform spinal fusion surgery based on the patient's symptoms and diagnosis and failure of conservative treatment. A magnetic resonance imaging (MRI) scan, myelogram, or computed axial tomography (CAT) scan, and sometimes, an electromyograph (EMG) are performed to diagnose the specific problem. Some of the most common disorders are herniated disc, degenerative disc disease, degenerative spondylolisthesis, spinal stenosis, and revision of previously failed low back surgery.

More than 10,000 anterior lumbar interbody fusions have been performed in the United States in the past 10 years. (5) These procedures have resulted in effective management of degenerative joint disease, instability, and spondylolisthesis, with approximately an 87% patient satisfaction rate. (5) The greatest advantage of anterior lumbar surgery is that back muscles and nerves are undisturbed, so recovery time is shorter compared to recovery for surgery that requires a posterior approach. Secondly, the fusion area is in the front of the spine where it is compressed, which tends to produce better fusion results. If the fusion becomes solid, the patient has a better chance of a permanent recovery without requiring reoperation.

PREOPERATIVE PREPARATION

After the patient is examined and a thorough history and physical is obtained, the surgeon discusses the findings with the patient. The surgeon explains options, benefits, risks, and complications and obtains informed consent. Possible risks and complications include

* bleeding complications (eg, injury to vessels could cause loss of function in one or both legs);

* bowel obstruction that could require reoperation;

* hardware fracture;

* implant migration;

* infection;

* persistent pain;

* pseudoarthrosis (ie, a failure to fuse);

* respiratory complications associated with anesthesia administration;

* sexual dysfunction in men (eg, retrograde ejaculation);

* spinal cord injury;

* sympathetic dysfunction (ie, a feeling of warmth or uncomfortable sensations in one or both legs);

* transitional syndrome (ie, increased stress on the discs above and below the fused level that may cause disc degeneration and pain); and

* thrombophlebitis and deep vein thrombosis. (6,7)

The surgeon or nurse discusses preoperative preparation and the surgical environment with the patient and his or her family members. The vascular surgeon who will open the abdomen and provide access to the spine for the orthopedic surgeon obtains informed consent and answers questions about the procedure. During a preoperative clinic visit, an anesthesia staff member discusses the patient's anesthesia options and answers questions regarding postoperative pain control methods. Laboratory tests are performed within a week before surgery and might include a complete blood count, electrolyte levels, blood typing and cross match, and coagulation tests. In addition, a 12-lead electrocardiogram (ECG) and chest x-ray may be performed if the patient's age (ie, older than age 35) or medical condition (eg, a past history of heart problems) warrants it. Female patients of childbearing age will take a pregnancy test.

DAY OF SURGERY

The patient is admitted to the same day surgery center on the day of surgery. The preoperative nurse monitors the patient's vital signs (eg, blood pressure, oxygen saturation) and ECG. The nurse places an IV line and prepares the IV antibiotics for administration along with other preoperative medications. Antibiotics for spinal fusion surgery include cefazolin 1 g, vancomycin 1 g, and ceftazidime 1 g. The patient will receive one or more of these medications depending on his or her size, medication allergies, and medical history.

PREPARING THE OR. The surgical technologist and circulating nurse ensure that the necessary instruments and equipment are available. These include vascular instruments for abdominal access and additional necessary supplies in case a bleeding problem occurs when the major vessels are retracted. Equipment should include an extra suction machine, autotransfusion assembly, vascular clamps, and clip appliers. The circulating nurse ensures that blood is readily available before the patient arrives in the OR. Radiology department personnel set up a fluoroscopic image intensifier (ie, C-arm) that will be used periodically during the procedure as determined by the surgeon.

GREETING THE PATIENT. The circulating nurse greets the patient on the morning of surgery and assesses the patient's knowledge of the impending procedure. The nurse reviews the patient's medical history, laboratory test results, ECG, and chest x-ray, and ensures that consent forms have been completed. If the patient or his or her family members have questions, the nurse answers them and provides reassurance.

The surgeon arrives in the preoperative area to check the patient. The surgeon and the patient confirm that the informed consent is accurate. The family members usually wait in the same day surgery waiting area until the surgeon comes to speak with them after the procedure is complete.

INTRAOPERATIVE CARE

Anesthesia staff members and the circulating nurse transport the patient to surgery on a stretcher. On arrival in the OR suite, the entire surgical team participates in a time out to confirm that all persons in the room agree on the surgical procedure to be performed, the surgical site, the patient's identity, the patient's allergies, necessary implants, and whether antibiotics have been administered as ordered.

The surgical team members place the patient in the supine position on a radiopaque bed so that when the bed is flexed, the abdomen will be extended to allow better exposure of the surgical site. The circulating nurse places a safety belt across the patient's thighs. The circulating nurse then helps the anesthesia care provider place the monitors (eg, ECG leads, blood pressure cuff, pulse oximetry device) on the patient and provides support and reassurance to the patient during the general anesthesia induction phase.

If the surgeon requests it, the circulating nurse places an indwelling urinary catheter to keep the patient's bladder decompressed. The catheter also is helpful if it becomes necessary to administer large volumes of fluids and blood in the event of a bleeding injury. The circulating nurse places bilateral sequential compression devices on the patient's feet or legs before induction to help prevent development of a thrombus or deep vein thrombosis.

POSITIONING AND PREPPING. The surgeon, anesthesia care provider, and circulating nurse work cooperatively to position the patient, ensuring that bony prominences are well protected by padding the patient's heels and placing the patient's head on a circular foam pad. The patient's arms are protected with foam pads and positioned flexed across the patient's upper chest. The arms are secured with tape to prevent them from sliding onto the abdomen and to secure the upper body to the bed (Figure 1a and 1b). The arm with the IV is placed on top so the anesthesia care provider can easily access the IV if needed. The circulating nurse applies the electro-surgery grounding pad and then cleanses the patient's skin with the surgeon's preferred prep solution. The nurse prevents pooling of the prep solutions under the patient to avoid potential bums.

[FIGURE 1 OMITTED]

ACHIEVING ANTERIOR EXPOSURE. The vascular surgeon generally achieves interior exposure through a midline incision or a left retroperitoneal approach. The abdominal cavity is not opened, but the abdominal contents are retracted to the side. The vascular surgeon pulls the aorta and vena cava to the right side of the spine to give the orthopedic surgeon access to the lumbar area. This is the point at which the large arteries and veins are most likely to be injured. The circulating nurse remains alert for bleeding that would require prompt action, such as supplying additional vascular instruments and supplies to the sterile field and readying the extra suction machine and autotransfusion device to recycle blood if needed.

After the vascular surgeon exposes the spine, the orthopedic surgeon removes the disc material and inserts two temporary spacers to move the vertebral bodies into proper alignment. The surgeon uses a reamer and threaded tap to drill a hole to hold the titanium cage containing the bone graft. The size of the cage is determined by x-rays, MRI scan, or CAT scan. The surgeon then places the bone graft, which can be autologous (ie, the patient's own bone) or allograft (ie, from a donor), into the cage along with a morphogenic protein product. Many patients elect to receive an allograft because of the site pain associated with donating their own graft. Donor site pain has been reported to persist for months or years after surgery. The benefits of receiving an allograft are that the patient will spend less time in the hospital and will experience a shorter recovery period with less pain. (8) Benefits of using an autologous graft include availability, less risk of rejection, and no risk of contracting HIV or Creutzfeldt-Jakob disease from the graft. The grafted bone will grow around and through the spacer implants causing a fusion to form, connecting the upper and lower adjacent vertebrae (Figure 2).

[FIGURE 2 OMITTED]

The surgeon places an anterior plating system secured with screws that fits well on the spine and does not impinge on adjacent arteries and veins. The surgeon positions the plate and screws using the C-arm to verify proper positioning. Titanium cylindrical cages are recommended because they are more flexible than steel cages. These cages are reported to promote excellent fusion rates, and patients have faster recovery rates. (9)

PRODUCTS THAT IMPROVE FUSION RATES

Recent advances in technology have introduced a variety of products that are implanted as part of the fusion process to improve fusion rates.

* Demineralized bone matrix is an allograft bone filler that is manufactured in putty, sheet, or gel form.

* Blood derived gels contain platelet derived growth factor and transforming growth factor beta.

* Ceramics are synthetic compounds that are used as bone filler at the fusion site.

* Bone morphogenic protein is a genetically engineered protein that is placed in the titanium cages to stimulate bone growth. Bone morphogenic protein has been particularly successful in improving fusion rates. (10)

POSTOPERATIVE CARE

The wound usually does not require a drain. After the wound is closed, the surgeon and scrub person apply a dressing. The anesthesia care provider wakens and extubates the patient. The surgical team members then cooperatively transfer the patient to a stretcher, and the circulating nurse and anesthesia care provider transport the patient to the postanesthesia care unit (PACU). The patient spends approximately an hour in the PACU where a nurse monitors the patient's vital signs, neurological status, pain level, and surgical site at regular intervals. After the recovery period, the patient is transported to the intensive care unit where he or she will stay overnight. The patient is transferred to the postoperative surgery unit the next day, and most patients return home within three to five days.

A nurse provides the patient with written and verbal postoperative instructions before the patient is discharged from the hospital. The instructions discuss activity and warning signs of an infection (ie, temperature > 101[degrees] F [38.3[degrees] C], redness at the surgical site, foul or purulent drainage from the wound).

It takes between three months and two years for fusions to mature and become solid. The fused bone will continue to grow stronger with exercise designed to strengthen the muscles and help increase flexibility of the spine. After the first postoperative visit, the surgeon advises the patient to exercise, which minimizes fatigue and helps prevent reinjury and back pain. The type of exercises recommended usually help strengthen muscles in the area weakened by preoperative nerve problems (eg, a pinched nerve caused by the bulging or herniated disc). The patient is advised to practice relaxation techniques and take pain medication before back pain becomes overwhelming. The patient also is instructed to eat properly and get sufficient rest to facilitate the healing process. Patients who smoke are advised to discontinue tobacco use because smoking interferes with the fusion process. Patients who work in occupations that increase their chances of reinjury may need to undergo vocational rehabilitation to learn different job skills.

CASE STUDY

Mr J is a 30-year-old construction worker who had not been able to work for almost a year because of lower back pain. He was diagnosed with postoperative failed back syndrome with chronic, intractable, low back pain and left lower-extremity radicular symptomatology. An MRI scan, CAT scan, and x-rays revealed that the patient's transitional L5 vertebra demonstrated symmetric dysplasia of the transverse processes of L5 (Figure 3). A discogram procedure showed L4-5 and L5-S1 degenerative disc disease with an annular tear (Figure 4).

[FIGURES 3-4 OMITTED]

The patient agreed to surgery after the risks and benefits were explained. The anterior lumbar interbody fusion procedure was performed at the L4-5 and L5-S1 levels. Femoral ring allograft spacers were augmented with bone morphogenic protein and master graft crystals. An anterior tension band plate was placed at L4-5, and a pyramid plate was placed at L5-S1 to limit motion so the fusion would become solid (Figure 5). Six months after surgery, x-rays verified that there was no motion at L4-5 and L5-S1, and there was a solid fusion developing across both levels (Figure 6). Nine months after surgery, Mr J was released to return to work with no limitations. Mr J had a two-level fusion, so he will be followed closely to watch for stress on the lumbar vertebrae above and below the fusion.

[FIGURES 5-6 OMITTED]

CONTINUING TECHNOLOGICAL ADVANCES

Technological advances (eg, titanium plates, products that enhance bone growth) have made it possible for patients to have one- or two-level spinal fusion procedures with near certainty that the fusion will solidify. The next generation of patients with back problems will benefit from technology that has advanced even further with the use of artificial disc replacements. This technology will revolutionize back surgery and provide many more patients with a solution to their back pain dilemma. (11) In addition to technology, excellent nursing care makes it possible for patients undergoing complex procedures to have the best possible outcome.

The authors acknowledge Ray Cunningham, MD, orthopedic spine surgeon, and Pat Humphreys, PA-C, physician assistant, Columbia Orthopedic Group, Columbia,

Mo, for providing information used in the patient case study.

NOTES

(1.) T G Lowe, "Degenerative disc disease and low back pain," (Oct 29, 2000) Spine Universe, http://www.spineuniverse.com/dis play.php/article242.html(accessed 27 Sept 2005).

(2.) "Injuries, illnesses, and fatalities," US Department of Labor, Bureau of Labor Statistics, http://bls.gov/iif/home.htm (accessed 27 Sept 2005).

(3.) L Greene, "Baby Boomers: Act Now, Save Bones," St Petersburg (Fla) Times, 15 Oct 2004, 1A. Also available at http://pqasb .pqarchiver.com/sptimes/results.html ? Qry Txt= Act+Now%2C+Save+Bones (accessed 27 Sept 2005).

(4.) C M Bono, C K Lee, "Critical analysis of trends in fusion for degenerative disc disease over the past 20 years: Influence of technique on fusion rate and clinical outcome," Spine 29 (Feb 15, 2004) 455-463.

(5.) M F Gornet, J K Burkus, T A Zdeblick, "rhBMP-2 and the LT-Cage[TM] device in the lumbar spine," paper presented at the American Academy of Orthopaedic Surgeons 69th Annual Meeting, Dallas, 13-17 Feb 2002.

(6.) L L Forsythe, "Laparoscopic spinal fusion procedures," AORN Journal 66 (October 1997) 637-643.

(7.) "Complications of spine surgery," Spine University, http://www.spineuniversity.com /public/spinesub.asp?id=69 (accessed 15 Sept 2005).

(8.) P F Ullrich, Jr, "Anterior lumbar interbody fusion (ALIF) surgery," (Sept 8, 1999) Spine-health.com, http://www.spine-health .com/print/topics/surg/overview/lumbar/lumb00 8.html (accessed 15 Sept 2005).

(9.) L Chotikul, "Spinal implants," RN 63 (May 2000) 28-31.

(10.) D E Rogers, "Advances in spinal fusion surgery with bone morphogenic protein, CareManagement 10 (August/September 2004) 22-24.

(11.) Q Bao, H A Yuan, "Artificial disc technology," Neurosurgery Focus 9 (October 2000) 24-30. Also available at http://www .aans.org/education/journal/neurosurgical/oct00 /9-4-14.pdf (accessed 27 Sept 2005).

Sharon Brady, RN, BSN, CNOR, is a staff nurse, same day surgery, University of Missouri Hospitals and Clinics, Columbia, Mo.

Sarah Jackson, RN, is a perioperative nurse, Harry S. Truman Memorial VA Hospital, Columbia, Mo.

Sharon Brady, RN; Sarah Jackson, RN

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