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11 Articles in Volume 13, Issue #6
Ask the Expert: Cash Patient on High-Dose Oxycodone With Negative Urine Screens
Cluster Headache: Providing Relief for a Debilitating Disorder
Editor's Memo: Keeping the Trust in Difficult Times
Gout: New Guidelines for Managing An Ancient Disease
History of Pain: A Brief Overview of the 17th and 18th Centuries
Letters to The Editor: Guidelines for Opioid Prescribing, Drug Legislation
Long-term Opioids, Sickle Cell Disease, and Pain Patches
Lumbar Spinal Stenosis: A Review of the Treatment Options and Modalities
Malabsorption of Opioid Medications
Non-Opioid Pharmaceutical Treatment of Cancer Pain
Treatment of Postherpetic Neuralgia With Low Level Laser Therapy

Lumbar Spinal Stenosis: A Review of the Treatment Options and Modalities

Lumbar stenosis is clearly a growing problem with the aging population. There are perhaps more treatment options for this diagnosis than any other spine pathology. Goldstein et al present a concise overview of the treatment options available today. In evaluating lumbar stenosis, it is important to realize discrepancies in the terminology and understanding of the disease process.

One common component of lumbar spinal stenosis is thickening of the ligamentum flavum. However, the etiology and pathophysiology of this finding is somewhat unclear. There has been tremendous debate as to whether the ligamentum flavum actually hypertrophies or simply buckles and becomes redundant. One large study based on measurements of disc herniation and aging found that buckling was the primary factor in thickened ligamentum flavum.1 An earlier National Institutes of Health (NIH)–sponsored study had similar findings.2 Other studies support the hypothesis that a facet degeneration alone without disc space narrowing can lead to physiologic ligament thickening.3 Furthermore, thickening occurs as a result of inflammation and fibrocartilaginous transformation can cause hypertrophy of the ligament.4 Consequently, the pathophysiology of ligament thickening is poorly understood.

Regarding the minimally invasive lumbar decompression (MILD) procedure, personally, I cannot attest to its efficacy. However, I have many trusted colleagues who perform the procedure with good results. The procedure is not without detractors, however. A recent study by a principal investigator and consultant raised serious doubts as to the long-term efficacy of the procedure.5 Wilkinson and Fourney questioned the long-term viability of results as early as 6 months post-procedure. My concerns regarding the procedure, for one, are that patients being selected for the procedure have likely not seen a surgeon. Secondly, I have yet to see a patient who medically is not a candidate for general anesthesia. Most anesthesiologists would argue it is better to intubate a patient with a controlled airway for a 30-minute procedure than to consciously sedate a patient for a similar-length percutaneous procedure like the MILD procedure without an attending anesthetist. Lastly, the long-term results and payor adaptation of this procedure remain to be seen.

Some clarification should be made regarding the authors’ description of surgical spinal decompression. The indications for laminectomy and discectomy are quite different. Laminectomies are typically reserved for relieving neurogenic claudication while discectomies are typically performed for radiculopathy. Gross total laminectomies are becoming rarer as the long-term consequences have been seen. The increased incidence of post-laminectomy kyphosis has led more surgeons to perform midline-sparing decompressions. These are done as hemilaminectomies or laminotomies, both of which can be done in a minimally invasive fashion.

Instrumented fusions are often done prophylactically to avoid instability. For example, a patient with severe facet arthropathy and stenosis may need to have the entire facet removed, which could render them unstable. Furthermore, bone-on-bone collapse of the disc space can benefit from an inter-body graft to distract the vertebrae bodies and provide indirect decompression. Finally, surgical fusion can often reduce a listhesis and gain additional indirect decompression.

With a paucity of Level 1 data, the most efficacious treatment for patients with lumbar stenosis remains somewhat elusive. As in most areas of medicine, a multidisciplinary approach to this pathology is the preferred course.

The incidence of lumbar spinal stenosis (LSS) in the United States has been estimated at 8% to 11% of the population.6 As the “baby boomers” age, an estimated 2.4 million Americans will be affected by LSS by 2021.7 As patients grow older, bony changes in the vertebrae—such as thickening of the pedicles, lamina, and facets—encroach on the space surrounding the nerve, causing loss of disc height and narrowing of the spinal canal and neural foramina. These degenerative spondylotic changes are usually associated with hyperplasia, fibrosis, and metaplasia of the surrounding ligamentous structures, including the intervertebral discs, causing LSS (Figures 1 and 2).8

People with LSS may or may not have back pain. Classic clinical findings of LSS include neurogenic claudication, sciatica, positional radicular pain, and weakness. The pain typically is exacerbated by standing and walking, and usually is decreased by positions that decrease lumbar spine lordosis (sitting and leaning forward). A key feature in the history of an LSS patient is the complaint of not having the ability to walk as far as one normally could without feeling symptoms, or without exacerbating already established symptoms.8

Another common cause of LSS is degenerative spondylolisthesis. This occurs when the vertebrae itself slips forward, causing a narrowing of the spinal canal. If the slip is moderate or severe, the emerging nerve roots get entrapped by the articular processes of the vertebra.9 The degree of slippage is also dependent on the patient’s anatomy. In patients with a wider spinal canal, then a mild slippage may be asymptomatic. If the spinal canal is normal width, then a mild or moderate slippage may produce symptomatology.9

LSS is a condition that affects many individuals, and can have a strong impact on activities of daily living, social aspects, physical stress, and the emotional status of a patient. The purpose of this article is to review the current therapies available for LSS, the indications for each one, and review the outcomes associated with each of the methods.

Non-surgical Management

The starting point for any pain management plan is conservative, non-surgical therapy. This includes physical therapy, anti-inflammatory medications, lumbar supports, opioid analgesics, steroid injections, and other modalities such as osteopathic manipulative treatment. Multiple studies have shown that conservative management is beneficial to patients suffering from LSS. Weinstein et al compared LSS and degenerative spondylolisthesis patients who received surgery to those who received conservative therapy. Although both patient groups showed that surgery was superior for treating these conditions, there was moderate improvement shown in the conservative treatment groups over time.10,11 In the Maine Lumbar Spine Study, 28% of the non-surgical group showed improvement with conservative therapy after 1 year of treatment (P=.003).12

When discussing conservative treatment, it is important to discuss the patient population who would benefit from such therapy. The goals of conservative management are slightly different than those of surgical therapy. With conservative management, the aim is to reduce inflammation, strengthen paravertebral and abdominal musculature, alleviate pain, and increase range of motion. It has been found that, despite these efforts, symptoms often recur, especially radiculopathy symptoms since these modalities typically have a temporizing effect.13

It is important to note that not all of these conservative treatments are benign. Initiation of NSAID therapy usually begins as a first-line treatment modality along with physical therapy. NSAIDs are contraindicated in patients with peptic ulcer disease, congestive heart failure, and renal disease due to the potential for serious adverse effects. When there is still inadequate pain control, opioid therapy may be initiated. Opioid therapy can cause constipation, dependence, and drowsiness. The side effects of medications always have to be discussed with patients, especially dependence on these agents, which is something to be seriously considered (Table 1).

Surgical Options

According to the American Academy of Orthopaedic Surgeons, “surgery for [LSS] is generally reserved for patients who have poor quality of life due to pain and weakness.” Each surgical procedure has its own special indications and requirements for the surgery to be successful.

Generally speaking, requirements for surgery include the following: patient must obtain medical clearance in order to tolerate the surgery, radiographic evidence must be present and match the clinical picture, and benefit must outweigh risk of surgery (Table 2). Here, we will examine some of the more popular and newer technologies available for spinal decompression surgery.

Interspinous Process Decompression Implant Device

Before considering the option of spinal decompression (laminectomy) surgery, and after failed conservative management, one may begin to think of smaller, less invasive operative procedures to alleviate LSS. One such option is an interspinous process decompression implant device, such as X STOP (Medtronic Spine LLC, Memphis, Tennessee). This device uses a titanium implant, which becomes fixated to the interspinous ligament between the symptomatic lumbar vertebrae, and decreases the extension of the spine at that level. When the vertebrae extend back, the spinal canal and neuronal foramina naturally become narrower, and in flexion, become significantly wider.14 This movement is a contributing pathophysiological cause of neurogenic intermittent claudication, which can be caused by lumbar spinal stenosis.

The premise of this device is to alleviate the narrowing of the spinal canal and foramina in extension, while preserving the dynamic changes experienced in flexion. This type of surgery would only be indicated for neurogenic intermittent claudication, which is significantly improved with flexion, and worsened by extension. In addition, other indications for this procedure are patients >50 years old, and candidates who have failed at least 6 months of nonsurgical treatment options.15 Also, radiological evidence of lumbar spinal stenosis, such as hypertrophied ligamentum flavum, narrowed lateral recesses, and central canal narrowing should be present for candidates of interspinous process implant devices.13

Several contraindications also exist for the X STOP device. They include allergy to titanium; spinal anatomy that prevents stable implantation, such as fracture and scoliosis with a Cobb angle greater than 25°; cauda equina syndrome; severe osteoporosis or osteoarthritis; systemic or localized infection at the implantation site; and spondylolisthesis greater than grade 1.15

Complications are, however, associated with the X STOP device. Barbagallo et al conducted a study in which 8 of 69 patients treated with the X STOP device (both single level and two level operations) experienced complications within 23 months of surgery. Four patients had device dislocation and 4 patients experienced spinous process fracture. Of all these complications, specific variations in the patients’ anatomies may have contributed. This suggests that careful attention must be paid to the patient’s anatomy before advancing with this surgical option.16

Since this implantation technology has been established in the recent years, long-term data and studies have not been thoroughly demonstrated. However, with mid-term evaluation, the X STOP device has come to show safety and efficacy. In a 2-year follow-up study, X STOP patients, when compared to control, improved in symptom severity scores (45.4% vs 7.4%), physical function (44.3% vs -.4%), and patient satisfaction (73.1% vs 35.9%).17

Minimally Invasive Lumbar Decompression (MILD)

MILD has been a procedure that recently established popularity in the United States for the treatment of LSS. This minimally invasive procedure provides an alternative to failed conservative management of LSS or open laminectomy. Furthermore, patients who may not be candidates for decompressive surgery, whether due to comorbidities or other reasons, may consider this option to treat their LSS. The procedure is conducted under fluoroscopic guidance, and as such allows for a good procedural safety profile. The procedure is typically done under local anesthesia with the patient consciously sedated.18 Essentially, this procedure is performed without removing any bony aspects of the vertebrae, but instead focuses on debulking the ligamentum flavum.19

Outcomes thus far for the MILD procedure have been favorable and comparable to other surgical options. In evaluating outcomes of LSS treatment modalities, several scales are used to quantify different aspects of the disease outcomes. The Visual Analogue Scale is used to assess patients’ pain pre- and post-treatment; the Oswestry Disability Index is used to compare mobility; the Zurich Claudication Questionnaire is used to assess symptom severity, patient function, and patient satisfaction with treatment; and the SF-12v2 Health Survey demonstrates quality of life. These surveys were asked preoperatively and 6 weeks postoperatively and all results seemed to correspond with a positive (improvement) patient response. When indirectly comparing the results of open or endoscopic laminectomy, MILD proved to have a 0% adverse effect rate or complication rate whereas the laminectomy procedure had a 2.1% medical complication rate and a 30-day mortality of 0.6%; however, these procedures were not directly compared to one another.18,19 Major adverse events such as dural tear, nerve injury, blood transfusion, epidural bleeding, or hematoma were not demonstrated at 30 days following the procedure as reported by Lingreen and Grider.20 Minor adverse effects were noted, particularly soreness at the procedure site, typically lasting an average of 3.8 days, and 5 of the 42 patients required opioid analgesia to relieve the discomfort. The MILD procedure proves thus far to be safe and efficacious, but due to the limited amount of long-term follow up, further studies need to be conducted. Also, to adequately compare MILD to other surgical options, randomized, prospective studies should be conducted.20

Decompressive Surgery Without Fusion

Surgical decompression of the spine is being performed more frequently because of the increase in life expectancy of the population.21 As mentioned previously, disorders of the spine are largely comprised of neurogenic compression resulting in symptoms of radicular pain, claudication, weakness, numbness and tingling, and pain in the lower back or buttocks. Aside from causing a great deal of discomfort, these symptoms can severely affect one’s quality of life by threatening their ability to perform normal activities of daily living.22 For the most part, the symptoms caused are structural in nature (due to normal wear and tear experienced with old age), and therefore, those problems can lead to compression of a nerve root, and in most severe cases the problem is treated by decompression of the affected area because conservative management is ineffective. In fact, in a study performed by Weinstein et al, which looked at surgical versus nonsurgical therapy for spinal stenosis, investigators concluded that surgical treatment was superior when compared to nonsurgical treatment at relieving symptoms and improving function.10

Spinal decompression can be performed by different techniques, but the most common ones are laminectomy and microdiscectomy.23 As noted by Dr. Highsmith in the introduction, indications for laminectomy and discectomy are quite different. The former is typically reserved for relieving neurogenic claudication, while the latter is typically performed to treat radiculopathy.23

As with any surgical treatment, spinal decompression should be considered once conservative treatment options, such as medications and physical therapy, have been exhausted without achieving any long-term or significant relief of symptoms.24 Some contraindications, which may exclude candidates from decompression surgery, include active spinal malignancy or infection as well as severe osteoporosis, spinal instability, and metal or other surgical implantation in the area to be treated. Complications or risks associated with these procedures include infection, bleeding, damage to the spinal cord or other nerves, weakening or loss of function of the legs, blood clots, leakage of spinal fluid, and worsening back pain.25

The outcomes of postsurgical decompression have been studied extensively and are debatable. In a prospective study by Jönsson et al, investigators found that patients who underwent surgical decompression for LSS deteriorated over time and those patients with symptoms lasting less than 4 years, as well as patients who had no back pain prior to the surgery, and no associated disease tended to have better outcomes. The reoperation rate was 18% within 5 years and this should be taken into perspective before considering decompressive surgery.26

Furthermore, according to a literature review performed by Detwiler et al, it was demonstrated that there was a higher patient satisfaction rate when fusion was conducted without instrumentation. Also discovered in the literature review was that when compared to instrumented patients, patients who were not instrumented had higher rates of spondylolisthesis later on (4 out of 9 nonfused patients and 7 out of 10 fused patients, as compared to 1 in 24 fused and instrumented patients). These conclusions, however, have not been directly compared to one another, and are independent.27 In one study conducted by Rompe et al, investigators looked at the long-term outcome of three different types of surgical decompression: undercutting decompression (36% of patients showing good to excellent outcomes), laminectomy and foraminal decompression alone, and foraminal decompression and laminectomy with instrumented fusion (30.8% and 23.8% showing good to excellent outcomes, respectively).28 Another study by Cornefjord et al examined the long-term outcomes of LSS patients undergoing decompressive surgery who were treated using fusion and decompression alone. Investigators reported excellent or good results in 65% of patients undergoing first-time surgical decompression with a mean follow-up period of 7 years. Cornefjord et al determined there were no statistical differences, judged by all the evaluated parameters, regarding the clinical outcome between patients who were fused and those who were not; neither were there any significant differences found between instrumented fusions compared to uninstrumented fusions.29 Finally, in a study by Airaksinen et al, investigators found that 62% of spinal stenosis patients (out of 438 total patients) had a good to excellent outcome in a 3.5-year follow-up surgery. This is the largest published study in patient populations.30 Thus, based on these studies, it seems that patients with little or no symptoms of back pain and no concomitant disease are recommended candidates for first-time surgical decompression. Additionally, it seems that studies conducted on patients undergoing decompression and fusion with or without instrumentation have found mixed results. Therefore, the surgeon’s discretion and assessment of potential or established instability must be carefully considered.27,31,32

Decompressive Surgery With Fusion

Another alternative to spinal decompression is adding vertebral fusion. Vertebral fusion uses bone grafts taken from cadavers or an allograft to place between two bony structures of the vertebral spine. This allows for the two vertebrae to fuse together and decrease their motion on one another. Furthermore, in addition to fusion, instrumentation may be added to further stabilize the vertebral structures, such as rods or pedicle screws. These additionally enhance the rigidity of the fusion.

Fusion is typically performed in patients who have vertebral instability due to either aggressive decompression surgery or to degenerative spondylolisthesis. In order to properly assess spinal stability, lateral flexion and extension films can demonstrate whether or not the vertebral segment is moving out of place.10 Since ligaments, bony structures, and other stabilizing structures holding the vertebrae are essentially removed in lumbar spine decompression surgery, there is a concern that the vertebrae might move or slip out of its normal location. When this occurs, this condition can cause further stenosing of the vertebral canal, and can compress the spinal cord and neuronal foramina.

The role of fusion in lumbar spinal stenosis has been a controversial topic for many years. Many different studies have shown either a benefit to fusion over decompression alone, or no additional benefit at all. Whether or not someone should receive fusion depends on many factors, such as comfort level and experience of the operating physician, amount of decompression that will take place, advancing technology in instrumentation, improved pre- and postoperative care, and most influentially, a lack of clear indications for spinal fusion.27

In certain conditions, such as degenerative spondylolisthesis, fusion has become the standard procedure to stabilize the spine.10 Regardless of baseline symptoms, according to Kleinstueck et al, better results were obtained by fusion with instrumentation (86% of patients reporting a “good” outcome at 12-month follow up) than with decompression alone (70%) for the treatment of spinal stenosis due to degenerative spondylolisthesis (P=.01). This suggests that the underlying problem of degenerative spondylolisthesis is addressed by the fusion and instrumentation to stabilize the vertebrae.31 In one prospective study, Herkowitz and Kurz established that 44% of spinal stenosis patients associated with degenerative lumbar spondylolisthesis were satisfied with decompression alone, and 96% of patients were satisfied with fusion and instrumentation along with decompression for degenerative spondylolisthesis.32 However, fusion does carry some additional risks. Davne et al described certain complications with transpedicular instrumentation such as screw misplacement, pedicle fracture and vessel damage, hardware loosening, increased operation time, and increased blood loss. Some of these complications may result in reoperation, which increases the morbidity versus simple decompression. This has to be taken into consideration when recommending treatment plans, since most of the patients who undergo these procedures are elderly and have comorbidities.33 Having mentioned these complications, fusion and instrumentation have proven to be superior to simple decompression for spinal instability and spondylolisthesis and have become the standard management of these conditions.9,10

Conclusion

LSS is a common, well-studied, and well-established condition with a number of treatment modalities. Treatment options range from conservative treatment to minimally invasive surgery, to decompressive surgery and fusion. Based on our review of the literature and studies, patients were more satisfied with surgery versus conservative management, especially minimally invasive surgery and surgery with fusion. Minimally invasive surgery, however, is still a new treatment modality and needs to stand the test of time to really establish its efficacy.

Last updated on: June 1, 2015
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