Introduction
Spinal stenosis is narrowing of spinal canal around soft tissue and bone which endangers nerves (1). It is very common in radiographic findings and inflicts people in their fifth and sixth decades of life (2). It can be acquired or rarely congenital. The prevalence of congenital spinal stenosis is 5/100000 with remarkable limping (3,4). These patients usually complain of gluteal and back pain (5,6). The symptoms worsen as one walks or stands, while sitting and leaning forward settle the pain (7). Due to slow improvement and accompanying complications, the disease needs prompt and proper treatment (8). Although some patients improve after non-surgical interventions (medications, physiotherapy and medical belt use), the effect of conservative treatment is limited and not helpful in patients with severe condition (9). Surgery is usually the best choice for them (10,11). Evidence has also proved that after failure of conservative treatment for about six months, surgery would be the effective solution (12,13). Different surgeries are recommended depending on the severity of the complications. The most common type of spine surgery is decompressive laminectomy (14) in which vertebral lamina is extracted to create more space for the neurons. Neurosurgeons may perform laminectomy with or without vertebrae fusion or removing a part of disc. If spondylolisthesis or scoliosis occurs, instrumentation may be recommended. Different devices such as wires, screws or rods are used to facilitate fusionand support instable areas of spine (15-16). The aim of our study was to evaluate the frequency of instrumentation use in patients with lumbar canal stenosis and/or disk herniation who referred to Shahid Beheshti and Ayatallah Roohani hospitals in Babol city in Mazandaran province, north of Iran.

Methods and Materials/Patients
This cross-sectional study was conducted on patients with lumbar disc herniation and lumbar stenosis who had referred to elective wards. Patients suffering from trauma, tumor, infectious disease, rheumatic and spondylolisthesis were excluded. All information of patients was recorded in a checklist including demographic characteristics, surgery technique, pathology, degree of improvement and up to 18 months follow-up. Written consent forms were obtained from all patients. In addition to clinical examination, simple radiography and lumbosacral MRI were performed. According to MRI and dynamic lumbosacral x-ray (flexion and extension), patients were operated by a neurosurgeon with instrumentation i.e. pedicular screw and rod fixation or without instrumentation through nerve decompression. Visual analogue scale (VAS) was then used to determine the degree of improvement. In this scale, if the level of pain was less than 4 complete improvement, if between 5-8 mild improvement and if upper than 8 no improvement was recorded for patient. Data were finally analyzed using SPSS (version 20), t-test and chi-square.
 

Discussion
Mean age of patients was 42.21±11.41 years old  in this study, which is similar to a study by Mashhadi Nezhad (mean age=43 years old) (17). Moreover, Molaiee et al. (2007) reported the mean age of lumbar disc herniation in Kordestan equal to 41 years old (18). According to prior research, disc herniation and spinal stenosis at different levels of pathology can limit people's activity, especially under 45 years of age (19). Most often, the disease affects young people in working ages, having remarkable economic impact as well (20).
In the present study, 51% of patients were men and 49% women. Yabuki et al. (2013) showed that 47.4% of men and 52.6% of women had spinal stenosis (21). Tabatabaei et al. (2012) in their study reported a higher number of male than female patients (45/1). Men are exposed to more mechanical tensions than women (22). However, several researches have suggested an equal prevalence of disc herniation and spinal stenosis in men and women (23).
We did not find any significant difference between the prevalence of disc herniation or spinal stenosis in the two groups of men and women. Similarly, Yabuki et al. (2013) reported no significant differences between men and women in terms of age (21). In another study, the prevalence of disc herniation and spinal stenosis was the same in both sexes (23).
In the present research, pathological considerations showed L4-L5 and L5-S1 as the highest involved levels. Similarly, Branden berg and Traynelis (1999) reported the same levels in 90% of cases. Several other studies published similar findings (17,18, 24-28). In fact, upper lumbar spine and extra-foraminal space are proportionately larger than the lower lumbar levels, so high mobility leads to early degeneration and herniation of the disc (29). Perhaps considering ergonomic principles in designing equipment and instruments can avoid damages to lumbar vertebral disc at different levels (30).
In our case, most of 150 surgery candidates were operated without instrumentation. Since 1934, surgery is the common standard treatment for lumbar radiculopathy due to prolapsed disc (31) and have yielded good results (32,33). However, annual government costs on diagnosis, treatment and rehabilitation resulting from spinal stenosis and lumbar disc herniation are heavy (34). Iran is no exception. Discovering the causes of this problem as well as prevention and surgery with or without instrumentation canbe very useful to reduce the government costs and help the patients have earlier return to their occupation and daily routines (35).  
We found 68% of patients with complete improvement after surgery. Mashhadi Nezhad et al. (2011) reported 94% improvement (17). In a study by Mobini et al. (2003), most patients with spinal stenosis decompression had improvement in lower limbs and complete satisfaction (36).
Complete improvement was seen more in men than women in our study. Other researchers proved that better surgical outcome correlated with male sex, higher education level, high income and better psychological status (37-39). Furthermore, the main cause of disease played an important role in patient's recovery (40). Some of these risk factors included the presence of trauma or injury in spine, weakness in the annulus, lifting heavy objects, exposure to high seismic waves and smoking (30,41). 

Conclusion
The results of this study showed that the prevalence of stenosis and herniation was the same in ages under 40 in both men and women. Most patients (63.3%) underwent surgery without instrumentation. It seems that raising awareness and recognizing the appropriate surgery techniques for spinal stenosis can help these patients for faster return to day life and social activities. Further case-control studies are suggested to achieve these aims.

Acknowledgments
This study is extracted from a doctoral thesis in Babol University of Medical Sciences. The authors would like to offer their special thanks to Clinical Research Development Unit of Shahid Beheshti University of Medical Sciences, Tehran.  

Funding
None.

Conflicts of Interest
The authors declare that they have no conflicts of interest.

Authors' Contribution
Seyyed Ebrahim Hejazian supervised the whole process of performing the research and co-authored this article. Mersedeh Dadpour collected the data and wrote the manuscript. 

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