Lumbar spinal stenosis (LSS) is a chronic degenerative disease with pain in the back, buttocks and legs aggrevated by walking and relieved after rest without associated vascular disease of lower extremities observed in patients between 50 and 60 years.
Lumbar spinal stenosis (LSS) and low-grade degenerative spondylolisthesis are frequently associated with facet joint degeneration, considered the main cause of low back pain.
Can be defined as a decrease in the size of the dural sac and spinal canal caused by arthritic changes of the facet joints, disc herniation combined with osteophytes, and spinal nerve root compression.
Developmental lumbar spinal stenosis is a maldevelopment of the dorsal spinal elements involving short pedicles and a trefoil bony spinal canal that increases the likelihood of neural compression at an earlier age.
The clinical definition includes “buttock or lower extremity pain, which may occur with or without low back pain, associated with diminished space available for the neural and vascular elements in the lumbar spine“ 1).
It is the most common reason for spinal surgery.
In 1973, Epstein identified lateral recess stenosis as another cause of canal narrowing 4). It was not until 1975 with the evolution of cross-sectional imaging and 1980's advances in CT and later MRI, that it became apparent that the soft tissue ligaments were a major cause of primary and also secondary stenosis.
Recent epidemiological studies have shown that the incidence of lumbar spinal stenosis is approximately 5.7% and increases with age, especially among 70 to 79-year-olds 5).
Lumbar spinal stenosis (LSS) is frequently observed in obese patients and the elderly especially due to the aging of the spine.
Increased Spinal inclination angle (SIA) and Body Mass Index BMI might be the most relevant risk factors for LSS
Growth in the facet joints, ligamentum flavum hypertrophy, disc degeneration, osteophytes and spondylolisthesis, all impinging on the spinal canal and intervertebral foramen cause the spinal canal to narrow down, and consequently result in spinal cord and nerve root compression 9).
A narrow spinal canal or spinal lateral stenosis can compress the central canal spinal cord, cauda equina, or nerve root, causing axonal disruption as a result of the pressure, neurohormone function disorders, and expansion of nerve sheath, resulting in the obstruction of blood flow, venous restriction, tissue hypoxia, and localized stasis, which stimulate the nerve endings and generate the symptoms of low back pain.
Although lumbar spinal stenosis often presents as a degenerative condition, some patients present with symptoms from lifelong narrowing of the spinal canal. These patients have congenital stenosis (CS) and present with symptoms of stenosis at a younger age. CS patients often have a distinct pathophysiology with fewer degenerative changes but present with multi-level involvement. In the setting of neurological symptoms, decompression-alone while preserving stability, has been proposed for both patient populations.
A systematic review was conducted using MEDLINE for literature published through December 2014. The first question focused on the effectiveness of lumbar spine surgery for symptomatic lumbar spinal stenosis in elderly patients. The second question focused on safety of surgical intervention on this elderly population with emphasis on perioperative complication rates.
Review of 11 studies reveals that the majority of elderly patients exhibit significant symptomatic improvement, with overall benefits observed for pain (change visual analog scale 4.4 points) and disability (change Oswestry Disability Index 23 points). Review of 11 studies reveals that perioperative complications were infrequent and acceptable with pooled estimates of mortality (0.5%), inadvertent durotomy (5%), and wound infection (2%). Outcomes seem less favorable with greater complication rates among patients with diabetes or obesity.
Based on largely low-quality, retrospective evidence, Shamji et al. recommend that elderly patients should not be excluded from surgical intervention for symptomatic lumbar spinal stenosis 10).
Currently, there is interest in minimally invasive surgery and various technical modifications of decompressive lumbar laminectomy without fusion.
Karp et al. 18) reviewed 158 patients who underwent epidural spinal injections for low-back pain with or without radiculopathy. These investigators found that depression and sleep disturbance were prognostic of worse Patient-Reported Outcome Measurement Information System (PROMIS) outcomes following epidural spinal injections.
Hägg et al. 19) performed a randomized controlled trial of 264 patients with severe chronic low-back pain who underwent either surgical or nonsurgical treatment, and assessed the impact of underlying affective disorders. They found that baseline depression correlated with worse outcomes following both operative and nonoperative treatment.
Interestingly, they also observed that depressed patients tended to have better outcomes with nonoperativecare, whereas nondepressed patients tended to have better outcomes with fusion.
In the study of Lubelski et al. 20) found that worsening depression (as measured by the PHQ-9) independently significantly predicted worse EQ-5D index outcomes following conservative treatment for LSS (p = 0.0002). This effect was most evident when comparing patients with severe depression, who improve 0.14 points less than those with no depression. This difference exceeds the MCID and confirms that depression is a poor prognostic factor for QOL improvement following nonoperative treatment for LSS. Further investigation is needed to determine whether treatment of depression prior to conservative or surgical management of LSS will improve posttreatment QOL outcomes. There are several limitations that should be considered when interpreting the results. Multiple treating physicians were included, and factors such as participation in physical therapy, treatment with NSAIDs, opioid medications and other nonsurgical treatments varied by practitioner and patient; this increases the variability, but also improves the generalizability.
They adjusted for the increased variability by using the random effect in the regression models. Many patients were also lost to follow-up at the 4-month evaluation.
The cohorts were similar for most characteristics; however, there were statistically significant, albeit small differences for estimated percent below poverty threshold and median income by zip code. The analysis is only valid for patients who did follow-up assessments at these time points. Additionally, this was a retrospective study with a relatively short follow-up period.
Prospectively designed studies with longer follow-up are needed to further validate the findings. Nonetheless, this is the largest study investigating the correlation between depression and QOL outcomes following conservative management of LSS.
Lubelski et al. have used the validated PHQ-9 measure of depression and have found a statistically and clinically significant impact on EQ-5D index outcomes.
The results of this study suggest that depressed patients with LSS have significantly less improvement following conservative management compared with nondepressed patients. Both physicians and surgeons who treat patients with LSS should consider using validated questionnaires such as the PHQ-9 for pretreatment evaluation of depression, to better assess the likelihood of success following treatment. Further investigation is needed to evaluate the effect of depression treatment prior to management of the spinal disorder. Future prospective studies with longer follow-up intervals may be useful in further evaluating the QOL outcomes in this patient population 21).
In cases of lumbar spinal stenosis (LSS) treated with surgical decompression, a postoperative magnetic resonance imaging (MRI) is sometimes required. In the experience of a study, the obtained decompression observed on early postoperative MRI tends to be disappointing compared to the decompression achieved intraoperatively. This raises the question of whether the early postoperative MRI, performed after lumbar decompression, is a fair representation of the 'real' decompression. A study investigated the correlation between intraoperative and postoperative measurements of the lumbar spinal canal.
Surgical decompression of the spinal canal effectively decreases the compression of the dural sac. However, early postoperative MRI after lumbar decompression does not adequately represent the decompression achieved intraoperatively 22).
Through the 1st postoperative year, patients with lumbar stenosis-without spondylolisthesis, scoliosis, or sagittal malalignment-and clinically significant back pain improved after decompression-only surgery 23).