In the normal healthy population, the sagittal alignment can be divided into four types based on the size of the sacral slope and lumbar lordosis. The effect of this sagittal profile especially type 2 with almost straight lordosis on the clinical outcomes of patients after mini-open discectomy is unknown. In this study, the results of patients who underwent mini-open discectomy were evaluated according to sagittal profile types of the patients.

Lumbar disc herniation (LDH) is the most common cause of sciatica and when conservative treatment fails or there is progressive neurological deficit, surgical excision of the herniated nucleosus pulposus is standard of care. Although minimally invasive methods such as endoscopic discectomy have been tried to be popular in recent years, open lumbar discectomy is still successfully performed in lumbar disc herniations due to some drawbacks of endoscopic techniques such as having long learning curve, higher radiation exposure to the surgeon, similar long-term results or the deception of commercial enterprises about endoscopic techniques and the pressure placed on surgeons in this direction.

Herniation of the nucleus pulposus as a result of massive LDH will inevitably result in disruption of normal lumbar biomechanics. Moreover, it has been shown that the healing process of the posterolateral herniation, which is biologically the weakest part of the posterior longitudinal ligament, will cause disc degeneration as a result of the repair and inflammation process in the annulus. However, the same authors claimed that, unlike the process in discogenic low back pain, macrophages in herniated discs can act to remove free pulposus fragments. There are few studies in the literature about the long-term consequences of this degeneration, which the investigators can consider as an accelerated aging process. Although clinically very successful results are obtained in the early postoperative period, it has been reported that the long-term success after discectomy may decrease from 90% to 60% over time. Depression or somatization, strenuous job and recurrent disc herniation or degeneration have been shown to cause long-term regression of results. In a prospective cohort study the authors reported a similar or worse leg pain rate in 30% of patients at the end of 10 years. In a study investigating reoperation after open lumbar discectomy, it was reported that the estimated rate of reoperation reached almost 45% at the end of 30 years.

In an extraordinary review evaluating the spinopelvic organization and the pathological adaptation to it, the mechanical stress, especially increased by hypolordosis, would cause the degenerative process in the spine to progress more rapidly. The basic theories explaining this are that the contact force, which is defined as the resultant force of the system created by gravity and abdominal pressure from the front and the dense paraspinal muscle mass from the posterior, mainly targets the discs. However, studies evaluating spinopelvic orientation in patients with LDH are limited. In a case-control study investigating the relationship between sciatica and spinopelvic harmony, more vertical sacrum, anterior C7 plumb line and hypolordosis were found in the LDH group. In a study examining the etiology and mechanism of sagittal imbalance caused by LDH, lumbar lordosis improved almost twice after endoscopic discectomy and LDH is probably one of the causes of compensatory sagittal imbalance.

Although there are studies on the pathogenesis and mechanics of LDH's etiology and post-discectomy results, the effect of the generally accepted normal lordosis types described by Roussouly P. on the degenerative process and patient scores after open standard discectomy is unknown. Therefore, in this study, the investigators aimed to compare the clinical results of patients with hypolordotic Type 2 and other types after open discectomy. Our hypothesis is that the mid-term clinical scores will be worse in Roussouly Type 2 patients with less lordosis.

Inclusion Criteria:

• Patients with complete skeletal maturation (>18 years)
• Lumbar disc herniation with >50% canal narrowing
• Severe leg and back pain associated with large LDH
• >6 weeks of unsuccessful conservative treatment
• Signed a written consent form

Exclusion Criteria:

• Patients with spondyloarthropathy
• Recurrent disc herniation
• Spinal instability
• >10 degrees of coronal deformity
• Incomplete data in the records

Adult patients with lumbar disc herniation who are candidates for surgical treatment