Ventral Transdural Herniation of the Thoracic Spinal Cord: Surgical Treatment in Four Cases and Review of Literature

Summary  Background. A specific cause of progressive Brown-Sequard syndrome has been identified: a ventral herniation of the thoracic spinal cord through the dural sleeve on one side. Method. Four female patients who were affected by a progressive Brown Sequard syndrome related to a transdural spinal cord herniation have been investigated and were submitted to surgery and postoperative evaluation. Findings. The MRI scan showed atrophy and forward displacement of the spinal cord on one side and adhesion of the spinal cord to the dura mater. CT myelography demonstrated the disappearance of the premedullar rim at the level of the herniation and the shadow of the extradural herniation. Surgical treatment consisted in the excision of the arachnoid cyst when there was one, section of the dentate ligament, release of the adhesions, detachment of the spinal cord from the hernial orifice, and lastly suture of the dural tear or placement by a patch. Follow-up examination showed motor improvement with persistent sensory deficit in two cases and stabilisation in two cases. Interpretation. The cause of the dural tear, either traumatic or congenital could not be confirmed in the four cases. Symptoms probably occur when herniation fills the orifice and strangulation happens which explains the late appearance and progressive evolution of this myelopathy. Mobilisation of the herniated spinal cord back into the intradural space can be achieved by surgery and may stop the evolution of the symptoms and signs.     

Surgical outcomes of posterior thoracic interbody fusion for thoracic disc herniations

Introduction

Surgical strategy for thoracic disc herniation (TDH) remains controversial. We have performed posterior thoracic interbody fusion (PTIF) by bilateral total facetectomies with pedicle screw fixation. The objectives of this retrospective study are to demonstrate the surgical outcomes of PTIF for TDH.

Materials and methods

We enrolled 11 patients who underwent PTIF for myelopathy due to TDH and were followed for at least 1 year. The mean age at surgery was 55.2 years and the average period of follow-up was 4.3 years. The levels of operation were T10–T11 in three cases, T12–L1 in three, and T2–T3, T3–T4, T9–T10, T11–T12, and T10–T12 in one case, respectively. The pre- and postoperative clinical status was evaluated according to the modified Frankel grade and the Japanese Orthopaedic Association (JOA) score modified for thoracic myelopathy. Additionally, postoperative complications were assessed. Local kyphosis at the operated segment and status of fusion were evaluated using plain radiographs and computed tomography.

Results

Improvement of at least one modified Frankel grade was observed in all but one patient. Average pre- and postoperative JOA scores were 4.9 and 8.8 points, respectively. The average recovery rate was 61 %. Bony union was observed in ten cases. One patient’s postsurgical outcome resulted in pseudoarthrosis, which required revision surgery due to kyphosis deterioration. Cerebrospinal fluid leakage was observed in one patient postoperatively with neither neurological deficit nor evidence of infection.

Conclusion

PTIF has produced satisfactory outcomes for myelopathy due to TDH. Therefore, PTIF is one of the surgical treatments of choice for patients with TDH causing myelopathy.     

Posterior and anterior epidural and intradural migration of the sequestered intervertebral disc: Three cases and review of the literature

Context: Dorsal migration of the sequestered lumbar intervertebral disc is an unusual and underrecognized pattern of lumbar disc herniation associated with pain and neurological deficit.Findings: Three patients presented with lower limb- and low back pain. MR imaging showed intracanalicular mass lesions with compression of the spinal cord and allowed precise localization of lesions in the extradural or intradural space. Diagnosis was straightforward for the patients with the posterior and anterior epidural disc fragments, whereas various differential diagnostic considerations were entertained for the patient with the intradural mass lesion. All patients underwent surgical removal of the sequestered disc fragments, and recovered full motosensory function. Surgical repair of the dura mater due to CSF leak was required for the patient with intradural disc herniation.Conclusion/clinical relevance: Posterior and anterior epidural, and intradural disc migration may manifest with clinical symptoms indistinguishable from those associated with non-sequestered lumbar disc hernias. Missed, migrated disc fragments can be implicated as a cause of low back pain, radiculopathy or cauda equina syndrome, especially in the absence of visible disc herniation. A high index of suspicion needs to be maintained in those cases with unexplained and persistent symptoms and/or no obvious disc herniation on MR images.     

Analysis of hard thoracic herniated discs: review of 18 cases operated by thoracoscopy

The authors retrospectively reviewed a series of 18 hard thoracic herniated discs (HTHD) operated by thoracoscopy. Isolated cases of HTHD have been reported in the literature, but no series describing these lesions has been published. Seventy-two percent of the herniated discs were situated between T8 and T12. Fifty-six percent of the patients had radiographic sequelae of Scheuermanns disease. Postoperatively, 83% had neurological improvement. In seven cases (39%), a plane separating the herniated disc and the dura mater was found surgically. In 11 patients, no separating plane was found during surgery. The lesion was intradural in three patients (17%) and adherent to the dura mater in eight (44%). Among these 11 patients, surgery was complicated by a dural tear in the first seven that led to a high risk of cerebrospinal fluid fistula: four of these seven patients had required surgical revision. In the last four, the zone of adhesion of the HTHD to the dura mater was preserved, successfully preventing dural tear     

中央型颈椎间盘突出症

４３例中央型颈椎间盘突出症病例，均累及颈髓引起不同程度的痉挛瘫。本组均无颈部外伤史。６５％的病例颈椎Ｘ线平片无异常所见；６０％的病例仅单间隙突出；７％的病例呈跳跃型多间隙突出；上位颈椎突出约占全部突出间隙的１４％．本组有两种临床类型：亚急性突出和缓慢型突出。游离髓核偶可刺破后纵韧带，突入椎管内甚至硬膜下腔，引起急性严重四肢瘫。缓慢突出型常为多间隙突出，少数合并后纵韧带钙化、骨化。３５例经前路间盘切除、椎间植骨融合；２例行椎管成形术。１例前路减压不彻底、半年后再行单纯椎板切除。平均随访７年月，９７％获得优良疗效，无手术并发症和加重例。     

Idiopathic Spinal Cord Herniation: Case Report and Literature Review

Summary  We report one case of spontaneous thoracic spinal cord herniation presenting with a progressive spastic paraparesis for 4 years in a 55 years old man. From preoperative MRI, showing a ventrally displaced atrophic spinal cord at T2–T3 level, a dorsal intradural arachnoid cyst was suspected. At operation, after a 3 level laminectomy, no arachnoid cyst was found and spinal cord herniation into a meningeal diverticulum was confirmed. The herniated myelon was replaced intradurally and the lumen of the diverticulum was filled with Teflon? settled with fibrin glue to prevent recurrence. Postoperatively some neurological recovery was achieved.  The literature was reviewed, regarding clinical and epidemiological features, proposed pathophysiological mechanisms, treatment options and outcome. Only 32 surgically proved cases of thoracic spinal cord herniation with no past history of spine trauma, injury or surgery were found.     

Cervical disc herniation causing localized ipsilateral popliteal pain

We report a patient with localized ipsilateral popliteal pain that we believe was caused by cervical disc herniation. A 52-year-old woman complained of an unusual severe aching pain in the right popliteal region. The pain increased gradually for 4 months despite the employment of conservative treatments. Eventually, the woman was unable even to stand immediately after waking because of the pain. However, physical examination of the right knee joint showed little abnormality. Although radiography of the knee joint showed slight osteoarthritic change, the pain remained unexplained. The patient also reported shoulder stiffness and slight numbness in the bilateral toes. Magnetic resonance imaging showed a large disc herniation on the right side of C3/4 and narrowing of the spinal canal at C4/5. Anterior cervical decompression and fusion surgery (C3–5) was performed to prevent impending myelopathy. After surgery the popliteal pain disappeared immediately and completely, suggesting that the cervical disc herniation had caused the pain. The pain has not recurred in almost 3 years after surgery. Received: April 26, 2001 / Accepted: August 14, 2001     

Disc degeneration of cervical spine on MRI in patients with lumbar disc herniation: comparison study with asymptomatic volunteers

An association between progression of cervical disc degeneration and that of lumbar disc degeneration has been considered to exist. To date, however, this association has not yet been adequately studied. Age-related changes in the cervical intervertebral discs were evaluated by magnetic resonance imaging (MRI) in patients with lumbar disc herniation, and compared with the MRI findings of healthy volunteers without lower back pain. The purpose of this study was to clarify whether the prevalence of asymptomatic cervical disc degeneration is higher in patients with lumbar disc herniation than in healthy volunteers. The study was conducted on 51 patients who were diagnosed as having lumbar disc herniation and underwent cervical spine MRI. The patients consisted of 34 males and 17 females ranging in age from 21–83 years (mean 46.9 ± 14.5 years) at the time of the study. The control group was composed of 113 healthy volunteers (70 males and 43 females) aged 24–77 years (mean 48.9 ± 14.7 years), without neck pain or low back pain. The percentage of subjects with degenerative changes in the cervical discs was 98.0% in the lumbar disc herniation group and 88.5% in the control group (p = 0.034). The presence of lumbar disc herniation was associated significantly with decrease in signal intensity of intervertebral disc and posterior disc protrusion in the cervical spine. None of the MRI findings was significantly associated with the gender, smoking, sports activities, or BMI. As compared to healthy volunteers, patients with lumbar disc herniation showed a higher prevalence of decrease in signal intensity of intervertebral disc and posterior disc protrusion on MRI of the cervical spine. The result of this study suggests that disc degeneration appears to be a systemic phenomenon.     

Cervical intradural disc herniation

STUDY DESIGN: A case report of anterior en bloc resected cervical intradural disc herniation and a review of the literature. OBJECTIVE: To discuss the pathogenesis of cervical intradural disc herniation. SUMMARY OF BACKGROUND DATA: Including this study case, only 17 cases of cervical intradural disc herniation have been reported. There have been few detailed reports concerning the pathogenesis of cervical intradural disc herniation. METHODS: A cervical intradural disc herniation at C6-C7, with localized hypertrophy and segmentally ossified posterior longitudinal ligament, is reported in a 45-year-old man who had Brown-Sequard syndrome diagnosed on neurologic examination. Neuroradiologic, operative, and histologic findings, particularly the pathology of the anterior en bloc resected posterior vertebral portion of C6 and C7, were evaluated for discussion of the pathogenesis. RESULTS: Adhesion of dura mater and hypertrophic posterior longitudinal ligament was observed around a perforated portion of the herniated disc, and histologic study showed irregularity in fiber alignment accompanied by scattered inflammatory cell infiltration and hypertrophy in the posterior longitudinal ligament. The cervical intradural disc herniation was removed successfully and followed by C5-Th1 anterior interbody fusion with fibular strut graft. Neurologic recovery was complete except for minor residual sensory disturbance in the leg 7 years after the surgery. CONCLUSIONS: Cervical intradural disc herniation is an extremely rare condition. The pathogenesis remains obscure. Only 16 cases have been reported in the literature, and there has been little discussion concerning the local pathology of the herniated portion. The pathogenesis of the disease in the patient reported here was considered to be the adhesion and fragility of dura mater and posterior longitudinal ligament. This was caused by hypertrophy, with chronic inflammation and ossification of the posterior longitudinal ligament sustaining chronic mechanical irritation to the dura mater, leading to perforation of the herniated disc by an accidental force.     

T1–2 disc herniation following an en bloc cervical laminoplasty

 We report a rare case of T1–2 disc herniation following cervical laminoplasty. A 56-year-old male patient presented with left foot-drop and gait disturbance of abrupt onset 11 years after a successful laminoplasty from C3–7. Magnetic resonance imaging revealed spinal stenosis at T1–2 due to intervertebral disc herniation and ligamentum flavum hypertrophy. Three days later, laminectomy with disc fragment excision was performed at that level. Two weeks after surgery, he was able to walk without assistance. Mechanical stresses may have directly affected the T1–2 intervertebral disc following laminoplasty and may have caused disc herniation. Received: October 17, 2001 / Accepted: February 1, 2002     

Clinical outcomes of microendoscopic decompression surgery for cervical myelopathy

Retrospective study on the results of microendoscopic decompression surgery for the treatment of cervical myelopathy. The purpose of this study was to describe the microendoscopic laminoplasty (MEL) technique as the surgical method in the treatment of cervical myelopathy, and to document the clinical outcomes for MEL surgery. Endoscopic surgery poses several challenges for the aspiring endoscopic surgeons, the most critical of which is mastering hand–eye coordination. With training in live animal and cadaver surgery, the technical progress has reduced the problem of morbidity following surgery. The authors have performed microendoscopic decompression surgery on more than 2,000 patients for lumbar spinal canal stenosis. Fifty-one patients underwent the posterior decompression surgery using microendoscopy for cervical myelopathy at authors’ institute. The average age was 62.9 years. The criteria for exclusion were cervical myelopathy with tumor, trauma, severe ossification of posterior longitudinal ligament, rheumatoid arthritis, pyogenic spondylitises, destructive spondylo-arthropathies, and other combined spinal lesions. The items evaluated were neurological evaluation, recovery rates; these were calculated following examination using the Hirabayashi’s method with the criteria proposed by the Japanese Orthopaedic Association scoring system (JOA score). The mean follow-up period was 20.3 months. The average of JOA score was 10.1 points at the initial examination and 13.6 points at the final follow-up. The average recovery rate was 52.5%. The recovery rate according to surgical levels was, respectively, 56.5% in one level, 46.3% in two levels and 54.1% in more than three levels. The complications were as follows: one patient sustained a pin-hole-like dura mater injury inflicted by a high-speed air-drill during surgery, one patient developed an epidural hematoma 3 days after surgery, and two patients had the C5 nerve root palsy after surgery. The epidural hematoma was removed by the microendoscopy. All two C5 palsy improved with conservative therapy, such as a neck collar. These four patients on complications have returned to work at the final follow-up. This observation suggests that the clinical outcomes of microendoscopic surgery for cervical myelopathy were excellent or showed good results. This minimally invasive technique would be helpful in choosing a surgical method for cervical myelopathy.     

Risk factors for back pain-related loss of working time after surgery for lumbar disc herniation: a 5-year follow-up study

The aim of this study is to explore the occurrence and the risk factors of back-related loss of working time in patients undergoing surgery for lumbar disc herniation. One hundred and fifty-two gainfully employed patients underwent surgery for lumbar disc herniation. Two months postoperatively, those patients completed a self-report questionnaire including queries on back and leg pain (VAS), functional capacity (Oswestry disability index—ODI, version 1.0), and motivation to work. After 5 years, lost working time was evaluated by means of a postal questionnaire about sick leave and disability pensions. The cumulative number of back pain-related days-off work was calculated for each patient. All 152 patients, 86 men and 66 women, were prescribed sick leave for the first 2 months. Thereafter, 80 (53%) of them reported back pain-related sick leave or early retirement. A permanent work disability pension due to back problems was awarded to 15 (10%) patients, 5 men (6%) and 10 women (15%). Median number of all work disability days per year was 11 (interquartile range [IQR] 9–37); it was 9 days (IQR 9–22) in patients with minimal disability (ODI score 0–20) at 2 months postoperatively and 67 days (IQR 9–352) in those with moderate or severe disability (ODI > 20; P < 0.001). The respective means were 61, 29, and 140 days/year. Multivariate analysis showed ODI > 20, leg pain, and poor motivation to work to be the risk factors for extension of work disability. Results of the present study show that after the lumbar disc surgery, poor outcome in questionnaire measures the physical functioning (ODI) and leg pain at 2 months postoperatively, as well as poor motivation to work, are associated with the loss of working time. Patients with unfavourable prognosis should be directed to rehabilitation before the loss of employment.     

Conus medullaris syndrome due to an intradural disc herniation: A case report

A 70-year-old male patient developed acute paraplegia due to conus medullaris compression secondary to extrusion of D12-L1 disc. After negative epidural examination intraoperatively, a durotomy was performed and an intradural disc fragment was excised. Patient did not regain ambulatory status at two-year follow-up. Intraoperative finding of negative extradural compression, tense swollen dura and CSF leak from ventral dura should alert the surgeon for the possibility of intradural disc herniation. A routine preoperative MRI is misleading and a high index of suspicion helps to avoid a missed diagnosis.     

脊髓型颈椎病术后颈椎间盘突出自行消失的原因探讨

目的：了解脊髓型颈椎病颈椎管扩大成型术后，颈椎间盘突出自行消失的原因并由此提出脊髓型颈椎病新的致病学说。方法：自１９９４年６月～１９９８年５月对脊髓型颈椎病行后路单开门椎管扩大成型术患者行临床及ＭＲＩ检查。结果：８例患者，术后４～１３个月，平均５．８个月复查时，颈椎ＭＲＩ检查发现，其术前ＭＲＩ显示的颈椎间盘突出影像消失，相应部位硬膜、脊髓无压迫。结论：（１）颈椎间盘退变突出后，出现颈椎节段性不稳定，刺激突出间盘周围组织，产生炎症性反应；（２）颈椎间盘突出、颈椎退变或颈椎管狭窄，致硬膜外腔压力增高，导致硬膜外静脉回流障碍，出现硬膜外静脉瘀滞、怒张。上述为脊髓型颈椎病发病的又一可能因素     

Intradural tumor and concomitant disc herniation of cervical spine

We report a rare patient of a simultaneous extradural and intradural compression of the cervical spinal cord due to co-existent intervertebral disc herniation and an intradural schwannoma at the same level. The intradural lesion was missed resulting in recurrence of myelopathy after a surprisingly complete functional recovery following anterior cervical discectomy. Retrospectively, it was noted that the initial cord swelling noticed was tumor being masked by the compression produced by the herniated disc. A contrast magnetic resonance imaging scan is important in differentiating intradural tumors of the spinal cord. A high index of suspicion is often successful in unmasking both the pathologies.     

后路经皮内镜下颈椎间盘摘除术治疗外侧型颈椎间盘突出症

目的分析后路经皮内镜下颈椎间盘摘除术治疗外侧型颈椎间盘突出症的临床疗效。方法回顾性分析自2015-10—2018-01采用后路经皮内镜下颈椎间盘摘除术治疗的27例外侧型颈椎间盘突出症,比较术前与术后1、6、12个月疼痛VAS评分及NDI指数。结果 27例均顺利完成手术,随访时间24~41个月,平均29个月。手术时间67~210 min,平均80 min,住院时间2~10 d,平均3 d。1例术中出现硬脊膜撕裂,1例术后出现切口渗液,轻度红肿,发热,分泌物细菌培养阴性,对症处理后治愈。27例术后1 d上肢疼痛和颈部疼痛症状均有明显改善,25例术后1 d疼痛消失或者明显减轻,24例术后第1 d肌力得到明显改善。末次随访时5例手术节段椎间盘突出加重。27例术后1、6、12个月疼痛VAS评分与NDI评分较术前明显改善,差异有统计学意义(P<0.05),但术后1、6、12个月间疼痛VAS评分与NDI评分比较差异无统计学意义(P>0.05)。结论后路经皮内镜下颈椎间盘摘除术治疗外侧型颈椎间盘突出症安全有效,术后恢复快,值得临床推广。     

Posterior approach for cervical fracture�Cdislocations with traumatic disc herniation

In the treatment algorithm for cervical spine fracture–dislocations, the recommended approach for treatment if there is a disc fragment in the canal is the anterior approach. The posterior approach is not common because of the disadvantage of potential neurological deterioration during reduction in traumatic cervical herniation patients. However, reports about the frequency of this deterioration and the behavior of disc fragments after reduction are scarce. Forty patients with traumatic disc herniation were observed. They represented 29.2% of 137 consecutive patients with subaxial cervical spine fracture–dislocations. Surgical planning was performed according to our two-stage algorithm. In the first stage, they were treated with posterior open reduction and posterior spine arthrodesis. In the second stage, anterior surgery was added for cases where neurological deterioration attributed to non-reduced disc fragments on postoperative magnetic resonance imaging (MRI). Neurological deterioration after posterior open reduction was not observed. Furthermore, 25% of total cases and 75% of incomplete paralysis cases improved postoperatively by ≥1 grade in the American Spinal Injury Association impairment scale. Reduction or reversal of disc herniation was observed in all cases undergoing postoperative MRI. For local sagittal alignment, preoperative 9.4° kyphosis was corrected to 6.9° lordosis postoperatively. The disc height ratio was 72.4% preoperatively and 106.3% postoperatively. The second stage of our plan was not required after the posterior approach in this series. The incidence of neurological deterioration after posterior open reduction was zero, even in cases with traumatic cervical disc herniation. Favorable clinical and radiological outcomes could be obtained by the first stage alone. Although preparations for prompt anterior surgery should always be made to cover any contingency, the need for them is minimal.     

Early neuromuscular customized training after surgery for lumbar disc herniation: a prospective controlled study

A prospective and controlled study of training after surgery for lumbar disc herniation (LDH). The objective was to determine the effect of early neuromuscular customized training after LDH surgery. No consensus exists on the type and timing of physical rehabilitation after LDH surgery. Patients aged 15–50 years, disc prolapse at L4–L5 or L5–S1. Before surgery, at 6 weeks, 4, and 12 months postoperatively, the following evaluations were performed: low back pain and leg pain estimated on a visual analog scale, disability according to the Roland–Morris questionnaire (RMQ) and disability rating index (DRI). Clinical examination, including the SLR test, was performed using a single blind method. Consumption of analgesics was registered. Twenty-five patients started neuromuscular customized training 2 weeks after surgery (early training group=ETG). Thirty-one patients formed a control group (CG) and started traditional training after 6 weeks. There was no significant difference in pain and disability between the two training groups before surgery. Median preoperative leg pain was 63 mm in ETG and 70 mm in the CG. Preoperative median disability according to RMQ was 14 in the ETG and 14.5 in the CG. Disability according to DRI (33/56 patients) was 5.3 in the ETG vs. 4.6 in the CG. At 6 weeks, 4 months, and 12 months, pain was significantly reduced in both groups, to the same extent. Disability scores were lower in the ETG at all follow-ups, and after 12 months, the difference was significant (RMQ P=.034, DRI P=.015). The results of the present study show early neuromuscular customized training to have a superior effect on disability, with a significant difference compared to traditional training at a follow-up 12 months after surgery. No adverse effects of the early training were seen. A prospective, randomized study with a larger patient sample is warranted to ultimately demonstrate that early training as described is beneficial for patients undergoing LDH surgery.     

Survivorship analysis of 150 consecutive patients with DIAM? implantation for surgery of lumbar spinal stenosis and disc herniation

Recently, the Device for Intervertebral Assisted Motion (DIAM™) has been introduced for surgery of degenerative lumbar disc diseases. The authors performed the current study to determine the survivorship of DIAM™ implantation for degenerative lumbar disc diseases and risk factors for reoperation. One hundred and fifty consecutive patients underwent laminectomy or discectomy with DIAM™ implantation for primary lumbar spinal stenosis or disc herniation. The characteristics of the 150 patients included the following: 84 males and 66 females; mean age at the time of surgery, 46.5 years; median value of follow-up, 23 months (range 1–48 months); 96 spinal stenosis and 54 disc herniations; and 146 one-level (115, L4–5; 31, L5–6) and 4 two-level (L4–5 and L5–6). In the current study, due to lumbosacral transitional vertebra (LSTV) L6 meant lumbarization of S1 and this had a prominent spinous process so that the DIAM™ was implanted at L5–6. Reoperations due to any reasons of the DIAM™ implantation level or adjacent levels were defined as a failure and used as the end point for determining survivorship. The cumulative reoperation rate and survival time were determined via Kaplan–Meier analysis. The log-rank test and Cox regression model were used to evaluate the effect of age, gender, diagnosis, location, and level of DIAM™ implantation on the reoperation rate. During a 4-year follow-up, seven patients (two males and five female) underwent reoperation at the DIAM™ implantation level, giving a reoperation rate of 4.7%. However, no patients underwent reoperation for adjacent level complications. The causes of reoperation were recurrent spinal stenosis (n = 3), recurrent disc herniation (n = 2), post-laminectomy spondylolisthesis (n = 1), and delayed deep wound infection (n = 1). The mean time between primary operation and reoperation was 13.4 months (range 2–29 months). Kaplan–Meier analysis predicted an 8% cumulative reoperation rate 4 years post-operatively. Survival time was predicted to be 45.6 ± 0.9 months (mean ± standard deviation). Based on the log-rank test, the reoperation rate was higher at L5–6 (p = 0.002) and two-level (p = 0.01) DIAM™ implantation compared with L4–5 and one-level DIAM™ implantation. However, gender (p = 0.16), age (p = 0.41), and diagnosis (p = 0.67) did not significantly affect the reoperation rate of DIAM™ implantation. Based on a Cox regression model, L5–6 [hazard ratio (HR), 10.3; 95% CI, 1.7–63.0; p = 0.01] and two-level (HR, 10.4; 95% CI, 1.2–90.2; p = 0.04) DIAM™ implantation were also significant variables associated with a higher reoperation rate. Survival time was significantly lower in L5–6 (47 vs. 22 months, p = 0.002) and two-level DIAM™ implantation (46 vs. 18 months, p = 0.01) compared with L4–5 and one-level DIAM™ implantation. The current results suggest that 8% of the patients who have a DIAM™ implantation for primary lumbar spinal stenosis or disc herniation are expected to undergo reoperation at the same level within 4 years after surgery. Based on the limited data set, DIAM™ implantation at L5–6 and two-level in patients with LSTV are significant risk factors for reoperation.     

Dural lesions in lumbar disc herniation surgery: incidence, risk factors, and outcome

In lumbar disc herniation surgery, dural lesions seem to be the most common complication today. Studies on incidence of and outcome after a dural lesion are mainly based on retrospective studies. In a prospective study within the framework of the Swedish Spine Register, 4,173 patients operated on for lumbar disc herniation were evaluated using pre- and 1-year postoperative protocols and complication registration. Mean patient age was 41 (18–81) years and 53% of the patients were male. 93% of the operations were performed on the two lowermost lumbar levels. The incidence of dural lesions in the material was 2.7%. In patients with previous disc surgery, the incidence was doubled, 5%, a significant increase (P = 0.02). Patients with dural lesions preoperatively had more back pain and inferior scores in general health and role emotional domains of the SF-36. These factors, however, were because they had been operated on previously, not related to the dural lesion as such. The relative improvement after surgery was similar whether a dural lesion had occurred or not. It is concluded that a dural lesion is a technical complication which must be solved at the time of surgery but which does not bear any negative implications on the long-term outcome for the patient.