The purpose of this study was to analyze the relationship between fracture pattern and the development of acute radiculopathy after osteoporotic lumbar compression fracture.
This study included 59 patients who underwent bone cement augmentation for osteoporotic compression fracture below the L2 level, which can lead to radiculopathic radiating pain. The patients were divided into two groups according to the presence of radiculopathy (group A : back pain only; group B : back pain with newly developed radiating pain). We categorized compression fractures into three types by the position of the fracture line. The incidence of newly developed radiculopathy was examined retrospectively for each compression fracture type.
The overall incidence of newly developed leg pain (group B) was 25%, and the frequency increased with descending spinal levels (L2 : 0%, L3 : 22%, L4 : 43%, and L5 : 63%). The back pain-only group (group A) had mostly superior-type fractures. On the other hand, the back pain with radiculopathy group (group B) had mostly inferior-type fractures. Most patients in group B showed significant relief of leg pain as well as back pain after bone cement augmentation.
The incidence of a newly developed, radiating pain after osteoporotic compression fractures increased gradually from the L3 to L5 levels. Most of these fractures were of the inferior type, and the bone cement augmentation procedures seemed to be sufficient for relief of both back and radiating pain.
Fracture; Osteoporosis; Radiculopathy
Synovial cysts are recognized as an uncommon cause of radicular and myelopathic symptoms. They are most frequently found in the lumbar region. The cervical spine or cervicothoracic junction is a rare location for a degenerative intraspinal synovial cyst as compared with the lumbar spine. At given cervical spinal levels, synovial cysts probably share clinical features with disc herniation and stenosis. However, the pathogenesis of synovial cysts remains still controversial. Here, we report a rare case of a synovial cyst in the lower cervical spine presented as Brown-Séquard syndrome and include a brief review of the literature. To the best of our knowledge, no previous report has been issued in the English literature on a synovial cyst presenting with Brown-Séquard syndrome. Neurologic function recovered completely after complete removal of the cyst and expansive laminoplasty.
Brown-Séquard syndrome; Synovial cyst; Cervical
The purpose of this study was to evaluate the efficacy of implant removal of percutaneous short segment fixation after vertebral fracture consolidation in terms of motion preservation.
Between May 2007 and January 2011, 44 patients underwent percutaneous short segment screw fixation due to a thoracolumbar burst fracture. Sixteen of these patients, who underwent implant removal 12 months after screw fixation, were enrolled in this study. Motor power was intact in all patients, despite significant vertebral height loss and canal compromise. The patients were divided into two groups by degree of osteoporosis : Group A (n=8), the non-osteoporotic group, and Group B (n=8), the osteoporotic group. Imaging and clinical findings including vertebral height loss, kyphotic angle, range of motion (ROM), and complications were analyzed.
Significant pain relief was achieved in both groups at final follow-up versus preoperative values. In terms of vertebral height loss, both groups showed significant improvement at 12 months after screw fixation and restored vertebral height was maintained to final follow-up in spite of some correction loss. ROM (measured using Cobb's method) in flexion and extension in Group A was 10.5° (19.5/9.0°) at last follow-up, and in Group B was 10.2° (18.8/8.6°) at last follow-up. Both groups showed marked improvement in ROM as compared with the screw fixation state, which was considered motionless.
Removal of percutaneous implants after vertebral fracture consolidation can be an effective treatment to preserve motion regardless of osteoporosis for thoracolumbar burst fractures.
Fusion; Percutaneous; Removal
Perforation of the hypopharynx, which can occur after anterior cervical approach, is a very rare type of complication. If diagnosed late, it can lead to very fatal course, such as mediastinitis and hematosepsis. Therefore, a precise and prompt diagnosis is crucial. When conservative treatment alone is not expected to heal the perforated site or is likely to lead to serious complications, surgical treatment becomes necessary. This report demonstrates that surgical intervention performed immediately after an early diagnosis can lead to the successful treatment of a large perforation in the hypopharynx on a 58-year-old male patient.
Hypopharynx; Perforation; Cervical
The purpose of this study was to compare the results of three types of short segment screw fixation for thoracolumbar burst fracture accompanying osteopenia.
The records of 70 patients who underwent short segment screw fixation for a thoracolumbar burst fracture accompanying osteopenia (-2.5< mean T score by bone mineral densitometry <-1.0) from January 2005 to January 2008 were reviewed. Patients were divided into three groups based on whether or not bone fusion and bone cement augmentation procedure 1) Group I (n=26) : short segment fixation with posterolateral bone fusion; 2) Group II (n=23) : bone cement augmented short segment fixation with posterolateral bone fusion; 3) Group III (n=21) : bone cement augmented, short segment percutaneous screw fixation without bone fusion. Clinical outcomes were assessed using a visual analogue scale and modified MacNab's criteria. Radiological findings, including kyphotic angle and vertebral height, and procedure-related complications, such as screw loosening or pull-out, were analyzed.
No significant difference in radiographic or clinical outcomes was noted between patients managed using the three different techniques at last follow up. However, Group I showed more correction loss of kyphotic deformities and vertebral height loss at final follow-up, and Group I had higher screw loosening and implant failure rates than Group II or III.
Bone cement augmented procedure can be an efficient and safe surgical techniques in terms of achieving better outcomes with minimal complications for thoracolumbar burst fracture accompanying osteopenia.
Burst fracture; Osteopenia; Fusion
Osseous bridging between lumbar transverse processes is an uncommon condition that may cause low back pain. In most cases, its etiology is alleged to be trauma to the back and only rarely has a congenital origin been indicated. Furthermore, most reported cases involved adults, the majority of whom were middle-aged. Here, the authors describe the case of the youngest girl reported to date with congenital transverse process bridging. As far as the authors' knowledge, there has been no report of congenital bridging of transverse processes in children or adolescents in Korea.
Low back pain; Transverse process; Osseous bridging
There has been no report of bilateral pedicle stress fractures involving two vertebrae. The authors describe a unique case of spondylolisthesis accompanying a bilateral pedicle stress fracture involving two vertebrae. De novo development of spondylolisthesis at the L5-S1 vertebrae accompanying a bilateral pedicle stress fracture at L4 and L5 was observed in a 70-year-old woman. The patient's medical history was unremarkable and she did not have any predisposing factors except severe osteoporosis. Interbody fusion with bone cement augmented screw fixation was performed. Surgical treatment resulted in good pain management and improved functional recovery.
Spondylolisthesis; Bilateral pedicle fracture; Osteoporosis
The purpose of this prospective study was to evaluate the efficacy and safety of screw fixation without bone fusion for unstable thoracolumbar and lumbar burst fracture.
Nine patients younger than 40 years underwent screw fixation without bone fusion, following postural reduction using a soft roll at the involved vertebra, in cases of burst fracture. Their motor power was intact in spite of severe canal compromise. The surgical procedure included postural reduction for 3 days and screw fixations at one level above, one level below and at the fractured level itself. The patients underwent removal of implants 12 months after the initial operation, due to possibility of implant failure. Imaging and clinical findings, including canal encroachment, vertebral height, clinical outcome, and complications were analyzed.
Prior to surgery, the mean pain score (visual analogue scale) was 8.2, which decreased to 2.2 at 12 months after screw fixation. None of the patients complained of worsening of pain during 6 months after implant removal. All patients were graded as having excellent or good outcomes at 6 months after implant removal. The proportion of canal compromise at the fractured level improved from 55% to 35% at 12 months after surgery. The mean preoperative vertebral height loss was 45.3%, which improved to 20.6% at 6 months after implant removal. There were no neurological deficits related to neural injury. The improved vertebral height and canal compromise were maintained at 6 months after implant removal.
Short segment pedicle screw fixation, including fractured level itself, without bone fusion following postural reduction can be an effective and safe operative technique in the management of selected young patients suffering from unstable burst fracture.
Screw fixation; Burst fracture; Bone fusion
Discal cyst is rare and causes indistinguishable symptoms from lumbar disc herniation. The clinical manifestations and pathological features of discal cyst have not yet been completely known. Discal cyst has been treated with surgery or with direct intervention such as computed tomography (CT) guided aspiration and steroid injection. The purpose of this study is to evaluate the safety and efficacy of the percutaneous endoscopic surgery for lumbar discal cyst over at least 6 months follow-up.
All 8 cases of discal cyst with radiculopathy were treated by percutaneous endoscopic surgery by transforaminal approach. The involved levels include L5-S1 in 1 patient, L3-4 in 2, and L4-5 in 5. The preoperative magnetic resonance imaging and 3-dimensional CT with discogram images in all cases showed a connection between the cyst and the involved intervertebral disc. Over a 6-months period, self-reported measures were assessed using an outcome questionaire that incorporated total back-related medical resource utilization and improvement of leg pain [visual analogue scale (VAS) and Macnab's criteria].
All 8 patients underwent endoscopic excision of the cyst with additional partial discectomy. Seven patients obtained immediate relief of symptoms after removal of the cyst by endoscopic approach. There were no recurrent lesions during follow-up period. The mean preoperative VAS for leg pain was 8.25±0.5. At the last examination followed longer than 6 month, the mean VAS for leg pain was 2.25±2.21. According to MacNab' criteria, 4 patients (50%) had excellent results, 3 patients (37.5%) had good results; thus, satisfactory results were achieved in 7 patients (87.5%). However, one case had unsatisfactory result with persistent leg pain and another paresthesia.
The radicular symptoms were remarkably improved in most patients immediately after percutaneous endoscopic cystectomy by transforaminal approach.
Lumbar discal cyst; Percutaneous endoscopic transforaminal cystectomy
There are technical limitations of multi-level posterior pedicle screw fixation performed by the percutaneous technique. The purpose of this study was to describe the surgical technique and outcome of minimally invasive multi-level posterior lumbar interbody fusion (PLIF) and to determine its efficacy.
Forty-two patients who underwent mini-open PLIF using the percutaneous screw fixation system were studied. The mean age of the patients was 59.1 (range, 23 to 78 years). Two levels were involved in 32 cases and three levels in 10 cases. The clinical outcome was assessed using the visual analog scale (VAS) and Low Back Outcome Score (LBOS). Achievement of radiological fusion, intra-operative blood loss, the midline surgical scar and procedure related complications were also analyzed.
The mean follow-up period was 25.3 months. The mean LBOS prior to surgery was 34.5, which was improved to 49.1 at the final follow up. The mean pain score (VAS) prior to surgery was 7.5 and it was decreased to 2.9 at the last follow up. The mean estimated blood loss was 238 mL (140-350) for the two level procedures and 387 mL (278-458) for three levels. The midline surgical scar was 6.27 cm for two levels and 8.25 cm for three level procedures. Complications included two cases of asymptomatic medial penetration of the pedicle border. However, there were no signs of neurological deterioration or fusion failure.
Multi-level, minimally invasive PLIF can be performed effectively using the percutaneous transpedicular screw fixation system. It can be an alternative to the traditional open procedures.
Posterior lumbar interbody fusion; Percutaneous; Minimally invasive surgery
Ligamentum flavum hematoma (LFH) is a very rare condition of dural compression; most are observed in the mobile cervical and lumbar spine regions. A 67-year-old man who had a long level interbody fusion at L3-S1 four years ago presented with symptoms suggestive of dural compression. Magnetic resonance imaging showed a posterior semicircular mass located at the adjacent L2-L3 level. After decompression of the spinal canal and removal of the mass lesion, pathological examination of the surgical specimen revealed a hematoma within the ligamentum. The patient fully recovered to normal status after surgery. Here, we report our experience with a LFH in the adjacent segment after a long level fusion procedure and discuss the possible associated mechanisms.
Ligamentum flavum; Hematoma; Adjacent segment
Bone cement augmentation procedures such as percutaneous vertebroplasty and balloon kyphoplasty have been shown to be effective treatment for acute or subacute osteoporotic vertebral compression fractures. The purpose of this study was to determine the efficacy of bone cement augmentation procedures for long standing osteoporotic vertebral compression fracture with late vertebral collapse and persistent back pain.
Among 278 single level osteoporotic vertebral compression fractures that were treated by vertebral augmentation procedures at our institute, 18 consecutive patients were included in this study. Study inclusion was limited to initially, minimal compression fractures, but showing a poor prognosis due to late vertebral collapse, intravertebral vacuum clefts and continuous back pain despite conservative treatment for more than one year. The subjects included three men and 15 women. The mean age was 70.7 with a range from 64 to 85 years of age. After postural reduction for two days, bone cement augmentation procedures following intraoperative pressure reduction were performed. Imaging and clinical findings, including the level of the vertebra involved, vertebral height restoration, injected cement volume, local kyphosis, clinical outcome and complications were analyzed.
The mean follow-up period after bone cement augmentation procedures was 14.3 months (range 12-27 months). The mean injected cement volume was 4.1 mL (range 2.4-5.9 mL). The unipedicular approach was possible in 15 patients. The mean pain score (visual analogue scale) prior to surgery was 7.1, which decreased to 3.1 at 7 days after the procedure. The pain relief was maintained at the final follow up. The kyphotic angle improved significantly from 21.2 ± 4.9° before surgery to 10.4 ± 3.8° after surgery. The fraction of vertebral height increased from 30% to 60% after bone cement augmentation, and the restored vertebral height was maintained at the final follow up. There were no serious complications related to cement leakage.
In the management of even long-standing osteoporotic vertebral compression fracture for over one year, bone cement augmentation procedures following postural reduction were considered safe and effective treatment in cases of non-healing evidence.
Long standing; Compression fracture; Osteoporosis; Bone cement
Lumbar disc herniation is extremely uncommon in children below 10 years of age. A 7-year-old boy is reported who presented with low back pain and left leg radiating pain. The pain started seven days prior to presentation and was attributed to performing the jumping kick without any previous warm-up. Magnetic resonance imaging revealed a posterolateral disc herniation at the L3-4 level and multiple degenerative changes. The patient received conservative treatment including limitation of sports activities, anti-inflammatory and muscle relaxant medications as well as physical therapy. After three months of the aggressive treatment the child was symptom free. We present here a lumbar disc herniation in one of the youngest patient.
Lumbar disc herniation; Child; Tae Kwon Do
Bilateral pedicle stress fracture is a rare entity and few cases have been reported in the literature. Furthermore, the majority of these reports concern previous spine surgery or stress-related activities. Here, the authors report ankylosing spondylitis as a new cause of bilateral pedicle stress fractures accompanying spondylolysis. The reported case adds to the literature on bilateral pedicle stress fracture and spondylolysis by documenting that ankylosing spondylitis is another cause of this condition.
Spine fracture; Spondylolysis; Ankylosing spondylitis
Balloon kyphoplasty is a minimally invasive procedure that is mainly performed for refractory pain due to osteoporotic compression fractures. The purpose of this study was to evaluate the results of balloon kyphoplasty performed at different times after an injury.
In this retrospective study, the records of 99 patients who underwent one level of balloon kyphoplasty between January 2005 and December 2007 were reviewed. The patients were divided into three groups : 21 patients treated within 3 weeks of an injury (the acute group), 49 treated within 3 weeks to 2 months of an injury (the subacute group), and 29 patients treated at more than 2 months after an injury (the chronic group). Clinical outcomes were assessed using a visual analogue scale (VAS). In addition, modified MacNab's grading criteria was used to assess the subjective patient outcome. The radiology findings, including vertebral height restoration and procedure related complications, were analyzed based on the different time intervals after the injury.
Patients in all three groups achieved marked pain relief in terms of the VAS within 7 days of the procedure. Good or excellent results were achieved by most patients in all three groups. However, the height restoration, the main advantage to performing a balloon kyphoplasty, was not achieved in the chronic group. Moreover, evidence of complications including cement leakage was observed significantly less frequently in the subacute group compared to the other two groups.
Although balloon kyphoplasty is an effective treatment for osteoporotic compression fractures, with regard to pain relief, the subacute stage appears to be optimal for treating patients with a balloon kyphoplasty in terms of achieving the best outcomes with minimal complications.
Balloon kyphoplasty; Osteoporosis; Compression fracture
The purpose of this study was to evaluate the efficacy of a transforaminal suprapedicular approach, semi-rigid flexible curved probe, and 3-dimensional reconstruction computed tomography (3D-CT) with discogram in the endoscopic treatment of non-contained lumbar disc herniations.
The subjects were 153 patients with difficult, non-contained lumbar disc herniations undergoing endoscopic treatment. The types of herniation were as follows : extraforaminal, 17 patients; foraminal, 21 patients; high grade migration, 59 patients; and high canal compromise, 56 patients. To overcome the difficulties in endoscopic treatment, the anatomic structures were analyzed by 3D reconstruction CT and the high grade disc was extracted using a semi-rigid flexible curved probe and a transforaminal suprapedicular approach.
The mean follow-up was 18.3 months. The mean visual analogue scale (VAS) of the patients prior to surgery was 9.48, and the mean postoperative VAS was 1.63. According to Macnab's criteria, 145 patients had excellent and good results, and thus satisfactory results were obtained in 94.77% cases.
In a posterolateral endoscopic lumbar discectomy, the difficult, non-contained disc is considered to be the most important factor impeding the success of surgery. By applying a semi-rigid flexible curved probe and using a transforaminal suprapedicular approach, good surgical results can be obtained, even in high grade, non-contained disc herniations.
Intervertebral disc herniation; Percutaneous discectomy; Posterolateal approach
We present a case of an acute psoas muscle hematoma following percutaneous endoscopic lumbar discectomy. A 60-year-old female who presented with far lateral lumbar disc herniation underwent endoscopic discectomy on the right side at the L4-5 level. On the second postoperative day, the patient complained of severe right flank and leg pain and her blood pressure decreased. A computed tomography scan showed a large acute psoas muscle hematoma at right L4-5 level. The patient was transfused with packed red blood cells and placed at absolute bed rest. After observing the patient in intensive care, the severe flank and leg pain subsided, but the mild back pain persisted. Although percutaneous endoscopic lumbar discectomy is an effective minimally invasive surgical technique for the treatment of lumbar disc herniation, this case highlights the inherent risks of acute lumbar segmental vessel injury.
Percutaneous endoscopic lumbar discectomy; Psoas muscle hematoma; Lumbar segmental vessel injury
Although most of sacral perineural cysts are asymptomatic, some may produce symptoms. Specific radicular pain may be due to distortion, compression, or stretching of nerve root by a space occupying cyst. We report a rare case of S1 radiculopathy caused by sacral perineural cyst accompanying disc herniation. The patient underwent a microscopic discectomy at L5-S1 level. However, the patient's symptoms did not improved. The hypesthesia persisted, as did the right leg pain. Cyst-subarachnoid shunt was set to decompress nerve root and to equalize the cerebrospinal fluid pressure between the cephalad thecal sac and cyst. Immediately after surgery, the patient had no leg pain. After 6 months, the patient still remained free of leg pain.
Sacral perineural cyst; Disc herniation
Although endoscopic procedures for lumbar disc diseases have improved greatly, the postoperative outcomes for high grade inferior migrated discs are not satisfactory. Because of anatomic limitations, a rigid endoscope cannot reach all lesions effectively. The purpose of this study was to determine the feasibility of endoscopic transforaminal suprapedicular approach to high grade inferior-migrated lumbar disc herniations.
Between May 2006 and March 2008, a suprapedicular approach was performed in 53 patients with high grade inferior-migrated lumbar disc herniations using a rigid endoscope and a semi-rigid flexible curved probe. One-to-four hours after surgery, the presence of remnant discs was checked with MRI. The outcomes were evaluated with the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) one week after surgery.
The L2-3 level was involved in 2 patients and the L3-4 level was involved in 14 patients, while the L4-5 level was involved in 39 patients. There were single piece-type in 34 cases and a multiple piece-type in 19 cases. Satisfactory results were obtained in all cases. The mean preoperative VAS for leg pain was 9.32±0.43 points (range, 7-10 points), whereas the mean ODI was 79.82±4.53 points (range, 68-92 points). At the last follow-up examination, the mean postoperative VAS for leg pain was 1.78±0.71 points and the mean postoperative ODI improved to 15.27±3.82 points.
A high grade inferior migrated lumbar disc is difficult to remove sufficiently by posterolateral endoscopic lumbar dscectomy using a rigid endoscope. However, a satisfactory result can be obtained by applying a transforaminal suprapedicular approach with a flexible semi-rigid curved probe.
Migrated disc herniation; Percutaneous endoscopic lumbar discectomy; Rigid endoscope; Flexible curved probe
The purpose of this study was to determine the efficacy of short segment fixation following postural reduction for the re-expansion and stabilization of unstable burst fractures in patients with osteoporosis.
Twenty patients underwent short segment fixation following postural reduction using a soft roll at the involved vertebra in cases of severely collapsed vertebrae of more than half their original height. All patients had unstable burst fracture with canal compromise, but their motor power was intact. The surgical procedure included postural reduction for 2 days and bone cement-augmented pedicle screw fixations at one level above, one level below and the fractured level itself. Imaging and clinical findings, including the level of the vertebra involved, vertebral height restoration, injected cement volume, local kyphosis, clinical outcome and complications were analyzed.
The mean follow-up period was 15 months. The mean pain score (visual analogue scale) prior to surgery was 8.1, which decreased to 2.8 at 7 days after surgery. The kyphotic angle improved significantly from 21.6±5.8° before surgery to 5.2±3.7° after surgery. The fraction of the height of the vertebra increased from 35% and 40% to 70% in the anterior and middle portion. There were no signs of hardware pull-out, cement leakage into the spinal canal or aggravation of kyphotic deformities.
In the management of unstable burst fracture in patients with severe osteoporosis, short segment pedicle screw fixation with bone cement augmentation following postural reduction can be used to reduce the total levels of pedicle screw fixation and to correct kyphotic deformities.
Unstable burst fracture; Osteoporosis; Short segment fixation
We report a rare case of delayed cement displacement after balloon kyphoplasty in patient with Kümmell's desease. A 78-year-old woman with Kümmell's desease at T12 level received percutaneous balloon kyphoplasty. Two months after surgery, the patient complained of progressive severe back pain. Computed tomographic scans revealed a breakdown of the anterior cortex and anterior displacement of bone cement. Although this complication is very rare, it is likely to occur in treatment of Kümmell's desease accompanying anterior cortical defect.
Kümmell's desease; Balloon kyphoplasty; Bone cement displacement
Pseudoaneurysm arising from the superficial temporal artery (STA) is a rare and potentially critical cause of palpable mass. Most pseudoaneurysms form as a result of blunt trauma and present as painless, pulsatile mass that may be associated with pathologic finding and enlarged size. We report a rare case of pseudoaneurysm arising from STA caused by blunt injury and diagnosed by 3-dimensional computed tomography (CT) angiography.
Pseudoaneurysm; Superficial temporal artery; Three-dimensional CT angiography
Aortic abdominal aneurysm rarely has been reported as causing osteolytic lesions of the spine. It may produce back and radiating pain patterns similar to those of several commonly encountered neurosurgical processes. We report a uncommon complication of huge pulsating aortic aneurysm causing severe vertebral erosion with incapacitating back and radiating pain.
Aortic aneurysm; Vertebral erosion
Kyphoplasty performed in the middle thoracic spine presents technical challenges that differ from those in the lower thoracic or lumbar region due to small pedicle size and angular severity for thoracic kyphosis. The purpose of this study was to evaluate the efficacy of balloon kyphoplasty through extrapedicular approach for the treatment of intractable osteoporotic compression fractures in the middle thoracic spine.
The patients who were performed with one level balloon kyphoplasty through extrapedicular approach due to painful osteoporotic compression fractures at T5-T8 from June 2003 to July 2005 were retrospectively analyzed. Imaging and clinical features were analyzed including involved vertebrae level, vertebral height, injected cement volume, clinical outcome and complications.
Eighteen female patients (age ranged from 60 to 77 years old) were included in this study. The average amount of the implanted cement was 4.2±1.5 cc. The mean cobb angle and compression rate were improved from 12.1±6.5° to 8.5±7.2° and from 30% to 15%, respectively. The mean pain score (visual analogue scale) prior to kyphoplasty was 7.9 and it decreased to 3.0 after the procedure. Cement leakage to the adjacent disc (2 cases) and paravertebral soft tissues (1 case) were seen but there were no major complications such as pneumothorax, segmental artery injury, pulmonary embolism, or epidural leakage.
Balloon kyphoplasty through extrapedicular approach is considered as a safe and effective in treating the middle thoracic regions with low complication rate.
Balloon kyphoplasty; Extrapedicular approach; Middle thoracic region; Osteoporotic compression fracture
Low back pain is common during pregnancy. However, the prevalence of symtomatic lumbar disc herniation is rare, and cauda equina syndrome due to disc herniation during pregnancy is even rarer. We report a rare case of lumbar disc herniation causing cauda equina syndrome during third trimester of pregnancy which successfully treated by endoscopic discectomy. This case shows that endoscopic discectomy can be the treatment option for the lumbar disc herniation during pregnancy.
Lumbar disc herniation; Pregnancy; Endoscopic discectomy