## 1 Introduction  
Lumber spinal stenosis (LSS), the narrowing of the spinal canal with neural compression, is the most common cause for spinal surgery in older adults in the U.S., afflicting over 200,000 individuals from 1988 to 2011 [1; 2]. LSS is commonly considered as the cause of low back pain due to age-related degenerative changes in older adults and often leads to lumbar surgery [2; 3; 4; 5]. In Taiwan, treatment costs for LSS have been estimated by the National Health Insurance Administration of the Ministry of Health and Welfare to have reached USD 460 million for 2.0 million patients in the year 2015. Classic symptoms of LSS include lower back pain and a combination of lower extremity symptoms, lumbago, neurogenic claudation, hypoesthesia, anesthesia of the legs, ataxia, weakness, and a feeling of heavy legs [2; 5; 6; 7]; neurogenic claudation, defined by [PERSON] [8], is also frequently associated with LSS. Since symptoms of LSS may range from asymptomatic to severe disability, clinical diagnosis is based on a combination of symptoms, medical history, physical examination, and imaging findings [3]. Of the various imaging modalities available, magnetic resonance imaging (MRI) has been considered ideally suited to delineate the presence, extent, and complications of degenerative spinal diseases [9]; therefore, it has been widely used to evaluate lumbar foraminal stenosis caused by events such as decreased height of an intervertebral disc, facet joint osteoarthritic changes, inferior verteba subluxation, and the protrusion of the annulus fibrosus [5; 10]. Imaging studies allow for anatomical classifications as central, lateral, or foraminal stenosis, and the L4-5 spinal discs are most frequently affected in LSS, followed by L3-4, L5-S1, and L1-2 [11]. Treatment options for LSS are categorized as conservative and surgical; conservative therapies include pain medication, epidural injections, rehabilitation such as manual therapy with a hands-on physical therapist, aerobic training, and exercise intervention to treat patients with mild to moderate symptoms [7; 11], and surgical intervention is considered if LSS symptoms do not improve with conservative therapies [12]. Surgeries aim to decompress the entrapped neural element or provide decompression through lumbar fusion; for example, a split-spinous process for laminotomies and disectomies to correct LSS can minimize muscular trauma, maintain spinal stability, and easily re-enable movement, shorten the duration of hospital stays, reduce postoperative back pain, and provide satisfactory neurological and functional outcomes [13]. When comparing conservative and surgical treatments, studies have reported conservative treatments having a success rate of 15-70% [4; 14; 15]; on the other hand, while surgeries can alleviate pain, disability, or claudication, the rates of major complications are high, as are costs--Truven MarketScan commercial data from 2013 estimated the average cost of each surgical decompression procedure to be approximately USD 687, and USD 2255 in inpatient services for lumbar fusions [16]. A review of various conservative versus surgical treatment comparison studies published up to February 2015 found that surgery was associated with high complication and reoperation rates, whereas on the other hand, no side effects were reported for any of the conservative treatment options [17]. Even minimally invasive surgery for LSS did not significantly reduce operating time, length of hospital stay, or reoperation rates, nor did it offer better pain relief in outcome scores such as the visual analog scale (VAS), the 36-Item Short-Form Survey, and Japanese Orthopaedic Association scores [12].