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although the prevalence of lumbar disc herniation in magnetic resonance imaging ( mri ) studies reaches 30% , it clinically affects only 1 - 2% of the people throughout their life [ 1 , 2 ] .
symptomatic lumbar disc herniation is more common in male and during the fourth and fifth decades of life .
natural history usually begins with a fluctuating low back pain ( lbp ) that eventually radiates to one of the lower extremities .
nonoperative treatment for four to six weeks is usually effective in 70% of the affected patients [ 4 , 5 ] . in those cases with refractory complains ,
most authors prefer surgical discectomy to conservative treatment [ 6 , 7 ] . due to this relative benign and self - limited course of lumbar disc herniation
, most authors recommend nonoperative treatment for the first few weeks of presentations , but what about the upper limit of this golden time ? some believe that too late surgical decompression is associated with worse outcomes [ 810 ] , while others do not consider delayed surgery as a poor prognostic factor [ 11 , 12 ] .
the aim of this study is to assess the surgical outcome of lumbar disc herniation based on preoperative sciatalgia duration .
we hypothesized that preoperative sciatalgia duration has no significant effect on surgical outcome of the patients with lumbar disc herniation .
in this retrospective study , after local institutional review board approval ( code number 89533 ) , we analyzed our surgically treated patients due to lumbar disc herniation in our orthopedic department from september 2007 to august 2011 .
the inclusion criteria were a primary sciatalgia due to one - level stable lumbar disc herniation , being refractory to more than six weeks of conservative treatment , and surgical decompression without instrumentation or fusion . to avoid distortion of the results ,
our exclusion criteria were the cases with revision surgery , cauda equina syndrome , unstable spinal stenosis requiring fusion and/or instrumentation , significant underlying disorders ( like uncontrolled diabetes mellitus , autoimmune diseases , tumors , hemorrhagic diasthesis , etc . ) , and a follow - up period of less than two years .
the patients with preoperative sciatalgia duration less than 12 months were placed in group a and the rest in group b. preoperatively , all the patients had anteroposterior and lateral standing lumbosacral radiographs , supine mri , and in some cases electrodiagnostic studies were also performed . disability and pain ( both in lumbar region and leg ) were measured by oswestry disability index ( odi ) and visual analogue scale ( vas ) on a numeric 0 to 10 scores [ 1315 ] .
a disability improvement of more than 10 points ( 20% ) in odi was considered significant clinically .
the patients ' subjective satisfaction was also rated as excellent , good , fair , or poor . after informing the patients about pros and cons of the surgical treatment
, all the patients signed the informed consent forms and then , all operations were performed by the first author ( farzad omidi - kashani ) with a similar surgical technique ( minimal incision , unilateral exposure , laminotomy , and partial discectomy ) throughout these years .
as soon as the patients were able to walk and urinate , they were discharged from the hospital . in postoperative era
, we also recorded the recurrence and revision rates for comparison between the groups . 
 statistical analysis .
we used wilcoxon test to compare postoperative improvement in pain and disability relative to preoperative status in each group .
statistical analysis was performed by statistical package for social sciences ( spss ) version 11.5 for windows ( spss inc .
, chicago , il , usa ) and p less than 0.05 was considered statistically significant .
after applying the inclusion and exclusion criteria , eleven patients were omitted from the study and 240 patients could fulfill our criteria .
there were 116 women and 124 men with a mean age of 36.4  5.9 years ( range 16 to 63 ) .
the mean duration of both preoperative sciatalgia and follow - up period were 13.3  4.9 months ( range 2 to 65 ) and 33.7  5.1 months ( range 24 to 72 ) , respectively .  
table 1 shows the demographic data and baseline characteristics of each group , separately . as shown in table 2
, surgery could significantly improve leg pain , low back pain , and disability in both groups .  
table 3 compares the effectiveness of surgery in group a with group b regarding the improvement in pain and disability .
as this table shows , duration of preoperative sciatalgia either less or more than 12 months did not affect the surgical outcomes significantly .
there were 29 cases ( 12.1% ) with recurrent lumbar disc herniation ( 15 at the same level , same side ; seven at the same level opposite side ; seven at the different levels ) .
from these , 12 cases ( 5% of the total cases ) underwent revision surgery , usually with transforaminal lumbar interbody fusion and pedicular screw fixation technique . regarding the recurrence and revision rates
, there was no significant difference between the two groups . in terms of patients ' satisfaction ,
again , we could find no statistical difference in patients ' subjective satisfaction rate between the two groups ( table 4 ) .
we designed a retrospective study on 240 patients who were equally placed into two groups : less and more that 12 months of preoperative sciatalgia in the patients with simple single level lumbar disc herniation . in this study
, we could find no significant differences in efficacy of surgical discectomy in terms of leg vas , lumbar vas , and odi improvement between the groups .
our results showed that the patients were satisfied with the surgical outcomes ( whether they had been operated with sciatica duration shorter or longer than 12 months ) .
due to relatively benign and self - limited course of lumbar disc herniation and probable significant complications coupled with surgical discectomy , initially a minimum of six weeks of nonsurgical treatment is recommended , but after this time there are great controversies about the impact of preoperative symptom duration on the surgical outcome of lumbar disc herniation [ 912 , 17 , 18 ] . in a study conducted by ng and
sell , on 113 consecutive patients with lumbar discectomy , the authors found a significant reverse relationship between preoperative duration of radiculopathy for more than 12 months and postoperative disability improvement . in this study
, surgical operations performed throughout the first 12 months of radiculopathy did not affect the outcome .
similar to our study , these authors did not find a correlation between preoperative duration of sciatalgia and postoperative vas improvement ( p = 0.09 ) . in another study conducted by nygaard et al . on 132 patients with lumbar disc herniation underwent discectomy , they found a golden time of preoperative symptoms less than eight months for obtaining better surgical outcomes and more probability of returning to work .
similarly , grvle et al . found that duration of the sciatica more than three months was significantly associated with a longer time to return to work and worse surgical results .
other proponents of this issue are jansson et al . , who in a study on 263 patients with lumbar discectomy with one - year followup , reported that smoking , short preoperative walking distance , and a long history of back pain were associated with poorer surgical outcome .
in the study we conducted , we did not consider smoking habit or walking ability separately and we mostly focused on odi , leg and lumbar pain .
we could not find that long duration of preoperative pain ( in leg or lumbar area ) is accompanied by worse surgical results . here
, we would like to mention some studies that like us could not find an association between preoperative sciatalgia duration and postoperative surgical outcomes [ 11 , 12 ] .
most of these studies are relevant to lumbar spinal stenosis ( and not directly related to lumbar disc herniation ) and believe that a delay of surgery does not worsen the prognosis of these patients [ 20 , 21 ] .
the patients with spinal stenosis and degenerative spondylolisthesis evaluated the impact of preoperative symptom duration less or more than 12 months on the treatment ( surgical or nonsurgical ) outcomes .
they finally concluded that the patients with ss and symptom duration < 12 months ( versus > 12 months ) had significantly better results with surgical or nonsurgical treatment . in the patients with degenerative spondylolisthesis , preoperative symptom duration had no relationship with postoperative clinical improvement .
although in the study we conducted , the operated cases were all affected by lumbar disc herniation , we also could find no relationship between preoperative symptom duration and postoperative clinical improvement . in conclusion
, our study shows that in the patients with lumbar disc herniation undergoing discectomy , longer duration of preoperative symptoms was not associated with worse surgical outcomes . albeit it should be noted that in our study , the number of patients with sciatica duration less than three or six months was small and consequently we could not statistically compare the impact of these durations on surgical prognosis .
if we could compare the groups with these periods of time , the results might have been changed .
other shortcomings of our study included its retrospective design and its inability to evaluate other probable important factors influencing the results .
it seems that the level of population culture , patient expectations , and insurance coverage may have some confounding roles .
it is proposed that in the future , a multicentric study in different countries throughout the world is to be carried out with a similar standard surgical and follow - up technique to avoid these confounding factors that may affect the results .
background . in lumbar disc herniation 
 , most authors recommend nonoperative treatment for the first few weeks of presentation , but what about the upper limit of this golden period ? 
 the aim of this study is to assess the effect of preoperative sciatica duration on surgical outcome of lumbar disc herniation 
 . methods . 
 
 we retrospectively evaluated 240 patients ( 124 males and 116 females ) with a mean age of 36.4  5.9 years ( range 16 to 63 ) surgically treated due to primary stable l4-l5 disc herniation . 
 the patients were placed into two groups : with more and less than 12-month duration of preoperative sciatalgia . 
 disability and pain were measured by oswestry disability index ( odi ) and visual analogue scale ( vas ) . 
 wilcoxon test and mann - whitney u test were used for statistical analysis . 
 results . 
 total mean duration of preoperative sciatalgia and follow - up period were 13.3 months ( range 2 to 65 ) and 33.7  5.1 months ( range 24 to 72 ) , respectively . 
 comparison between the groups showed that duration of preoperative sciatalgia either less or more than 12 months did not affect the surgical outcomes significantly . 
 conclusions . 
 more or less than 12-month duration of preoperative sciatalgia may not affect the surgical outcomes of simple lumbar disc herniation in the patients undergoing discectomy .