Martin Barth

Primary Limited Lumbar Discectomy with an Annulus Closure Device: One-Year Clinical and Radiographic Results from a Prospective, Multi-Center Study

Objective Discectomy as a treatment for herniated lumbar discs results in outcomes after surgery that are not uniformly positive. Surgeons face the dilemma between limited nucleus removal which is associated with a higher risk of recurrence, or more aggressive nucleus removal which may lead to disc height loss and persistent back-pain. annulus closure devices may allow for the benefits of limited nucleus removal without the increased risk of recurrence. This is an interim report of an ongoing 24-month post-marketing study of the Barricaid® annulus closure device, consisting of a flexible polymer mesh that blocks the defect, held in place by a titanium bone anchor. Methods We prospectively enrolled 45 patients at four hospitals, and implanted the Barricaid® after a limited discectomy. annulus defect size and volume of removed nucleus were recorded. Reherniations were reported, pain and function were monitored and imaging was performed at regular intervals during 24 months of follow-up. Results At 12 months postsurgery, pain and function were significantly improved, comparing favorably to reported results from limited discectomy. Disc height has been well maintained. One reherniation has occurred (2.4%), which was associated with a misplaced device. No device fracture, subsidence or migration has been observed. Conclusion The use of an annulus closure device may provide a reduction in reherniation rate for lumbar discectomy patients with large annulus defects who are at the greatest risk of recurrence. Using such a device should provide the surgeon increased confidence in minimizing nucleus removal, which, in turn, may preserve disc height and biomechanics, reducing degeneration and associated poor clinical outcomes in the long-term. A randomized multicenter study evaluating limited discectomy with and without the Barricaid® is currently underway, and will provide a higher level of evidence.

Protecting facet joints post-lumbar discectomy: Barricaid annular closure device reduces risk of facet degeneration

Lumbar discectomy is an effective treatment for lumbar disc herniation (LDH). Although the majority of patients experience successful outcomes, a significant fraction will experience a recurrence of their back pain due to facet joint degeneration. Facet joint degeneration after discectomy may be the result of excessive nuclear removal, disc space narrowing, and annular injury. This study investigated whether implantation with the Barricaid annular closure device (ACD) during discectomy reduced the rate of facet degeneration. Inclusion criteria were primary lumbar disc herniation failing conservative treatment, Visual Analog Scale (VAS) Leg≥40/100, Oswestry Disability Index (ODI)≥40/100 and defects that were ≤60 mm2 (Barricaid arm only), and patient age 18-75. CT interpretations were collected preoperatively and 12 months post-discectomy. Patients implanted with Barricaid had significantly reduced rates and grades of facet degeneration than patients without Barricaid. Reinforcing the annulus fibrosus with Barricaid during lumbar discectomy may slow the progression of facet joint degeneration.

Surgical Management of Basilar Artery Laceration Caused by Transorbital Penetrating Injury: Case Report

Transorbital penetrating injuries are rare and present with a heterogeneity of intracranial injury patterns that require individualized therapeutic procedures. In this report, we describe the case of a distal basilar artery laceration in a 16-month-old boy caused by accidental transorbital penetration with a pencil. Surgical removal of the pencil was performed, but hemostasis could only be achieved by clipping the impaired vessel. Adequate diagnostics and an individualized surgical strategy are necessary to deal with these life-threatening injuries.

Impairment of Dynamic Pressure Autoregulation Precedes Clinical Deterioration after Aneurysmal Subarachnoid Hemorrhage

This study was designed to evaluate the potential of the dynamic autoregulation index (ARI) to serve as an early warning system for an imminent clinical deterioration after subarachnoid hemorrhage (SAH).

Occurrence of discal and non-discal changes after sequestrectomy alone versus sequestrectomy and implantation of an anulus closure device

Sequestrectomy alone represents a procedure for the treatment of lumbar disc herniation. For selected cases, an anulus closure device (ACD) can be implanted which may result in lower reoperation rates. However, comparative magnetic resonance imaging (MRI) changes and their clinical relevance of both procedures are unclear and have not been reported so far. Clinical and MRI data of patients after limited discectomy with ACD implantation (group ACD; N=45) and patients after sequestrectomy alone (group S; N=40) with primary lumbar disc herniation were compared retrospectively. Pain intensity on the visual analogue pain scale (VAS), oswestry disability index (ODI) or the patient satisfaction index (PSI) were collected. Disc signal intensity, Modic type changes, endplate reactions, anular tears and reherniations were investigated using MRI before and <18months postoperative. Morphologic changes were correlated with clinical outcome. There was no difference in VAS back, VAS leg or ODI/PSI after the operation although group S showed significantly more reherniations in MRI. The overall rate of repeated surgery at the same level was similar with a trend in favour of the ACD group (P=0.729). Significantly more patients of the ACD group experienced endplate erosions after surgery (P<0.001). Both groups experienced progression of disc signal intensity, Modic type changes, and anular tears with most MRI signs being without clinical relevance. ACD implantation is associated with a significantly lower reherniation rate in MRI but showed a significantly higher rate of endplate erosions. The structural changes do not appear to be clinically relevant.

Core herniation after implantation of a cervical artificial disc: case report

IntroductionCervical artificial discs (CADs) represent an established surgical option in selected patients with cervical spinal disc degeneration. Though CADs have been available for many years, there is a lack of information concerning long-term safety, durability and implant-related failure rates.Materials and methodsThe authors describe the failure of a M6-C CAD (Spinal Kinetics, Sunnyvale, CA, USA).ResultsEight years after implantation of a CAD of the M6 type, a 39-year-old female presented with new clinical signs of cervical myelopathy. Radiologically, medullar compression due to posterior core herniation was the suspected cause. The damaged CAD was removed and the segment fused. During revision surgery, rupture of the posterior structures could be detected. Possible mechanisms leading to implant failure are discussed.ConclusionAs there is no standard regarding clinical and radiological follow-up for patients with CADs, radiological long-term follow-up investigations seem to be justified for exclusion of implant failure.

Effect of anular closure on disk height maintenance and reoperated recurrent herniation following lumbar diskectomy: two-year data.

OBJECTIVE To assess the potential benefits of disk reherniation reduction and disk height maintenance in limited diskectomy combined with the implantation of the anular closure device. SUMMARY AND BACKGROUND DATA Postoperative disk height loss is apparent in most patients undergoing lumbar diskectomy for herniated nucleus pulposus. Less favorable patient outcomes are associated with significant loss in disk height that can occur after aggressive disk tissue removal. More conservative disk removals, however, are often burdened by the increased risk of recurrent disk herniation. METHODS Two prospective single-arm studies on patients treated with limited diskectomy and an anular closure device were conducted. Outcome measures included disk height maintenance relative to preoperative values, Oswestry Disability Index, back pain, leg pain, and complications such as reherniations. Patients were evaluated preoperatively and postoperatively at 6 weeks and at 3-, 6-, 12-, and 24-month time points. RESULTS A total of 75 patients were included in this cohort consisting of 40 men and 35 women with an average age of 40 years. Disk height maintenance within the group overall was 90% at 24 months. Overall, 97% of the treated disks demonstrated disk height maintenance of at least 75% of preoperative levels at 12 months and 92% at 24 months. Disk height maintenance was correlated with less nucleus removal. Patient disability, back pain, and leg pain were significantly improved from preoperative levels at 6 weeks and maintained over the course of study. There was a single symptomatic reherniation requiring surgical intervention within this series. CONCLUSIONS Limited lumbar diskectomy combined with the use of an anular closure device provided very low rates of disk reherniation and exhibited excellent disk height maintenance and sustained disability, leg pain, and back pain improvement within a 24-month postoperative study period. As with prior diskectomy studies, disk height maintenance was correlated with lower nucleus removal, although recurrence was less than in prior reports of limited diskectomy. Anular closure may allow for achievement of both objectives.

Development of a Low-Cost Polymethylmethacrylate Stand-Alone Cervical Cage: Technical Note

BACKGROUND AND STUDY AIMS Stand-alone cervical cages aim to provide primary stability, yield solid fusion in the long-term course, and maintain physiologic alignment. However, many implants designed for these purposes fail in achieving these goals. Following implantation, relatively high rates of cage subsidence and failure of disc height maintenance may lead to cervical kyphosis and poor alignment of the cervical spine. At the same time, costs for cage implantation are relatively high compared with their unfavorable radiologic performance. Thus the aim of the study was to develop and test mechanically a low-cost polymethylmethacrylate (PMMA) cage with similar mechanical and procedural properties compared with a commercial polyetheretherketone (PEEK) cage. MATERIAL AND METHODS Following determination of the cage design, a casting mold was developed for the production of PMMA cages. Nine cages were produced and compared with nine PEEK cages using static compression tests for 0 and 45 degrees according to the recommendations of the American Society for Testing and Materials. Mean compressive yield strength, mean yield displacement, mean tensile strength, and mean stiffness were determined. RESULTS At 0 degrees axial compression, the mean compressive yield strength, mean displacement, and mean tensile strength of the PMMA cage was significantly higher compared with the PEEK cage (p < 0.001). Stiffness of both implants did not differ significantly (p = 0.903). At 45 degrees axial compression, PEEK cages could not be investigated because slipping of the holding fixture occurred. Under these conditions, PMMA cages showed a mean compressive yield strength of 804.9 ± 60.5 N, a mean displacement of 0.66 mm ± 0.05 mm, a mean tensile strength of 7.92 ± 0.6 N/mm(2), and a mean stiffness of 1,228 ± 79.4 N/mm. CONCLUSIONS The newly developed PMMA cage seems to show similar to superior mechanical properties compared with the commercial PEEK cage. Considering a preparation time of only 10 minutes and the low price for the PMMA material, the cost-benefit ratio clearly points to the use of the PMMA cage. However, clinical effectiveness has to be proven in a separate study.

The spontaneous arterial blood pressure rise after aneurysmal subarachnoid hemorrhage - a biphasic phenomenon.

OBJECTIVES A spontaneous blood pressure (BP) rise is frequently observed after aneurysmal subarachnoid hemorrhage (aSAH). The current study was designed to characterize the time course of this BP rise and its relation to clinical and radiological parameters. METHODS The diastolic (DBP), mean (MAP), and systolic (SBP) BP values were determined in 61 aSAH patients from day 0 to 9. The patients initial status was evaluated by the world federation of neurological surgeons scale and the Hijdra scale. The clinical outcome was quantified by the modified Rankin Scale, the Glasgow Outcome Scale Extended, and the National Institute of Health Stroke Scale. The degree of proximal and global vasospasm was calculated by comparison of the baseline angiography on day 0 and the control angiography on day 8. Furthermore, the influence of propofol and norepinephrine application was analyzed. RESULTS DBP, MAP, and SBP demonstrated an early rise in all patients from day 2 till 5 (p<0.001) and remained hypertensive until day 9. No significant correlation could be detected between this early BP rise and most clinical and radiological variables. From day 8 onwards, a divergence of the SBP courses was detected between patients with severe vs. non-severe global vasospasm. There was a secondary, norepinephrine independent SBP rise in patients with severe global vasospasm that significantly correlated with the initial Hijdra-scale and an unfavorable clinical outcome. CONCLUSIONS The results demonstrate a biphasic BP course with a uniform early BP rise in all patients and an additional delayed SBP rise in patients with severe global vasospasm.

Radiological and clinical results of patients after ACDF with and without preoperative software-assisted cage selection

OBJECTIVE Comparison of software facilitated preoperatively-selected cages versus standard intraoperatively-selected cages, assessing radiological and clinical outcomes of patients after single level cervical discectomy and fusion (ACDF). METHODS Cages of study group patients were preoperatively chosen via software-aided dimensioning. Controls obtained cages determined by intraoperative trail implants. Primary endpoints were segmental height (SH), regional angulation (RA) and global cervical angulation (GCA) measured on plain radiographs before, immediately and 12 months after surgery. Neck pain on the visual analogue scale, the neck disability index, and patient satisfaction index recorded at 12 months follow up (FU) were the secondary endpoints. RESULTS Each group comprised of 20 patients and both depicted similar demographics and operated segmental levels. Mean postoperative SH was significantly increased in both study and control groups, p<0.001* and p=0.006* respectively. Immediate postoperative gain of lordosis was only significant for the study group p<0.001*. At 12 months FU, SH and RA decreased significantly in both groups. GCA and all secondary endpoints were similar for various measured time points. The two groups did not show any significant difference for all investigated parameters. CONCLUSION The radiographical and clinical outcomes of patients receiving cages preoperatively selected by software-assistance are similar to that of patients obtaining conventionally chosen cages. However the former allows for better regional gain/restoration of lordosis.