Application of restorative neurostimulation for chronic mechanical low back pain in an older population with 2-year follow up.

INTRODUCTION: Data on the Medicare-aged population show that older patients are major consumers of low back pain (LBP) interventions. An effective approach for patients with mechanical LBP that has been refractory to conservative management is restorative neurostimulation. The efficacy of restorative neurostimulation has been demonstrated in multiple prospective studies, with published follow-up over 4 years, showing a consistent durable effect. METHODS: To further examine the effect of restorative neurostimulation in an older demographic, data from three clinical studies were aggregated: ReActiv8-B prospectively followed 204 patients, ReActiv8-C study prospectively followed 87 patients and ReActiv8-PMCF prospectively followed 42 patients.Two hundred and sixty-one patients were identified with complete 2-year follow-up and divided into cohorts of equal size based of age quartiles.At 2 years from device activation, patients in either cohort were classified by change in disability (Oswestry Disability Index (ODI)) or change in pain score(NRS/VAS) and assessed as proportion of patients per group at each time point. Additionally, health-related quality of life (HRQoL) (EQ5D-5L) was longitudinally compared with baseline. Differences in proportions were assessed using χ2 and continuous variables by repeated measures analysis of variance. RESULTS: The oldest quartile (n=65) had a median age of 60 (56-82) years compared with the entire population (n=261) who had a median age of 49 (22-82) years. The completer analysis on patients with 2 years of continuous data showed improvement of a 50% in pain was achieved by 62% and 65% and a 15-point ODI improvement in 48% and 60% in the oldest quartile and entire population, respectively. HRQoL (EuroQol 5-Dimension) improved from baselines of 0.568 and 0.544 to 0.763 and 0.769 in the oldest quartile and entire population respectively. All age quartiles improved statistically and clinically over baseline. CONCLUSIONS: This aggregate analysis of three independent studies provides insight into the performance of restorative neurostimulation in an older population. Patients derived significant and clinically meaningful benefit in disability, pain and HRQoL. When compared with a similarly indicated cohort of younger patients, there were no statistically or clinically significant differences.

Real-World Evidence for Restorative Neurostimulation in Chronic Low Back Pain-a Consecutive Cohort Study.

BACKGROUND: Neuromuscular instability of the lumbar spine resulting from impaired motor control and degeneration of the multifidus muscle is a known root cause of refractory chronic low back pain (LBP). An implantable neurostimulation system that aims to restore multifidus motor control by stimulating the L2 medial branch of the dorsal ramus thereby relieving pain and reducing disability has demonstrated clinically significant benefits in the clinical trial setting. The 1-year results of a single-site real-world cohort study are presented. METHODS: This study recruited 44 consecutive patients with refractory, predominantly nociceptive axial chronic LBP, evidence of multifidus dysfunction, and no surgical indications or history of surgical intervention for chronic LBP. Each patient was implanted with a neurostimulation device. Pain (numeric rating scale), disability (Oswestry Disability Index), and quality of life (5-level EuroQol 5-Dimension) outcomes were collected at baseline and 3, 6, and 12 months after activation. RESULTS: Statistically significant improvements in pain, disability, and quality of life from baseline were seen at all assessment time points. At 12 months after activation, mean ± standard error of the mean numeric rating scale score was reduced from 7.6 ± 0.2 to 3.9 ± 0.4 (P < 0.001), Oswestry Disability Index score was reduced from 43.0 ± 2.8 to 25.8 ± 3.9 (P < 0.001), and 5-level EuroQol 5-Dimension index improved from 0.504 ± 0.034 to 0.755 ± 0.039 (P < 0.001). No lead migrations were observed. One patient required revision due to lead fracture. CONCLUSIONS: Restorative neurostimulation is a new treatment option for well-selected patients with refractory chronic LBP. Clinically meaningful improvements in pain, disability, and quality of life demonstrated in routine clinical practice are consistent with published results of controlled trials.

Clinical performance of a bone-anchored annular closure device in older adults.

Background: Lumbar discectomy is a common surgical procedure in middle-aged adults. However, outcomes of lumbar discectomy among older adults are unclear. Methods: Lumbar discectomy patients with an annular defect ≥6 mm width were randomized to receive additional implantation with a bone-anchored annular closure device (ACD, n=272) or no additional implantation (controls, n=278). Over 3 years follow-up, main outcomes were symptomatic reherniation, reoperation, and the percentage of patients who achieved the minimum clinically important difference (MCID) without a reoperation for leg pain, Oswestry Disability Index (ODI), SF-36 Physical Component Summary (PCS) score, and SF-36 Mental Component Summary (MCS) score. Results were compared between older (≥60 years) and younger (<60 years) patients. We additionally analyzed data from two postmarket ACD registries to determine consistency of outcomes between the randomized trial and postmarket, real-world results. Results: Among all patients, older patients suffered from crippling or bed-bound preoperative disability more frequently than younger patients (57.9% vs 39.1%, p=0.03). Among controls, female sex, higher preoperative ODI, and current smoking status, but not age, were associated with greater risk of reherniation and reoperation. Compared to controls, the ACD group had lower risk of symptomatic reherniation (HR=0.45, p<0.001) and reoperation (HR=0.54, p=0.008), with risk reductions comparable in older vs younger patients. The percentage of patients achieving the MCID without a reoperation was higher in the ACD group for leg pain (81% vs 72%, p=0.04), ODI (82% vs 73%, p=0.03), PCS (85% vs 75%, p=0.01), and MCS (59% vs 46%, p=0.007), and this benefit was comparable in older versus younger patients. Comparable benefits in older patients were observed in the postmarket ACD registries. Conclusion: Outcomes with lumbar discectomy and additional bone-anchored ACD are superior to lumbar discectomy alone. Older patients derived similar benefits with additional bone-anchored ACD implantation as younger patients.

Surgical Experience and Complications in 50 Patients Treated with an Anular Closure Device Following Lumbar Discectomy.

OBJECTIVE: To examine the results of an anular closure device for prevention of lumbar disc reherniation in daily routine practice. METHODS: Fifty patients with large anular defects were treated with limited discectomy and a bone-anchored anular closure device. The device physically occludes the defect in the anulus fibrosus and is intended for prevention of lumbar disc reherniation. Pain scores on a visual analogue scale, back function on the Oswestry Disability Index, and neurological status were noted. Symptomatic reherniation and reoperation rates were assessed at each follow-up. Surgical findings and complications, device-related and/or procedure-related, were recorded. Follow-up was 6, 12, 26, and 52 weeks. RESULTS: Mean anular defect height/width was 4.6 mm/10.1 mm. The overall symptomatic reherniation and reoperation rate was 2%. During the 1-year follow-up period, mean back pain decreased from 43 to 8 (P < 0.001), leg pain decreased from 71 to 4 (P < 0.001), and the Oswestry Disability Index decreased from 46 to 5 (P < 0.001). Among 15 patients with preoperative neurological deficits, improvements in neurological function were noted in 14 (93%). There were no serious device-related complications. CONCLUSIONS: The presented study shows promising early results in using the anular closure device. The procedure is safe with significantly fewer reherniations than for patients with large anular defects without anular closure. Further studies with longer follow-up periods are warranted to prove these findings for long-term outcomes.

Two-year real-world results of lumbar discectomy with bone-anchored annular closure in patients at high risk of reherniation.

PURPOSE: To determine the safety and effectiveness of limited lumbar discectomy with additional implantation of an annular closure device (ACD) among patients at high risk of herniation recurrence treated in routine clinical practice. METHODS: This was a prospective, single-center study of lumbar discectomy for sciatica caused by intervertebral disc herniation with adjunctive ACD implantation to reduce herniation recurrence risk among high-risk patients with large annular defects. Patients returned for follow-up visits at 6 weeks, 12 weeks, 26 weeks, 1 year, and 2 years. Main outcomes included reoperation, herniation recurrence, back pain severity, leg pain severity, and Oswestry Disability Index (ODI). The minimum important difference was defined as ≥ 20 mm decrease relative to baseline for leg pain severity, ≥ 20 mm decrease for back pain severity, and ≥ 15-point decrease for ODI. RESULTS: Among 75 high-risk patients (mean age 45 years, 59% female), the cumulative event incidence through 2 years was 4.0% for reoperation and 1.4% for herniation recurrence. Mean leg pain severity decreased from 73 to 6 (p < 0.001), back pain severity decreased from 51 to 13 (p < 0.001), and ODI decreased from 49 to 7 (p < 0.001). The percentage of patients achieving the minimum important difference was 91% for leg pain, 65% for back pain, and 94% for ODI. CONCLUSION: In patients at high risk of herniation recurrence following limited lumbar discectomy in routine clinical practice, additional implantation of an ACD was safe and reherniation recurrence rates were low at 2-year follow-up, which is favorably compared to reported rates in high-risk patients.

A retrospective and consecutive analysis of the epidemiology and management of spinal cavernomas over the last 20 years in a single center.

Spinal cavernous malformations (SCM) are rare lesions often presenting with acute onset of symptoms and progressive neurological deterioration due to hemorrhage into the spinal cord. With the aid of modern techniques, their surgical removal became much safer. The present study was undertaken to analyze the outcome of our series of surgically and conservatively treated patients with SCM. Over a period of 20 years, 20 surgically treated and 5 conservatively managed patients with spinal cavernous malformations were identified and enrolled into this analysis. Demographic data, clinical symptoms, localization and extension of the cavernoma, as well as pre- and postoperative neurological status were obtained. The clinical status was assessed using the Frankel score. Patients were followed up clinically and by MRI. Before surgery, 90% (18/20) of our surgical patients were classified as Frankel D (93.8%), whereas two patients (10%) were graded C. None of the patients had a worse Frankel score at the time of discharge. Eighty percent of them (16 cases) remained unchanged, and 20% (4 patients) improved during the first follow-up (mean 6.3 months, range 2-17 months). All improved patients had a superficially located SCM and were operated early (≤3 months). No worsening was observed during extended follow-up (range 9-134 months, mean 44.7 months). Five nonsurgically treated patients showed no significant clinical deterioration over a period of 6.7 years (mean, range 2.9-8 years). SCM localization and number of involved segments had no influence on outcome. Our data show that SCM can be resected with favorable neurological outcome by using intraoperative neuromonitoring. Within the follow-up period, patients treated conservatively remained in a stable neurological condition.

Management of traumatic spinal injuries in children and young adults.

PURPOSE: Spinal injuries are rarely seen in pediatric patients and therapeutic options are still poorly defined. The present study is aimed to present our experience with a rather large series of children and young adults suffering from traumatic spinal injury. PATIENTS AND METHODS: Between 1990 and 2010, 75 consecutive pediatric patients with spinal injuries were treated in our institution. Mean age was 15 years, ranging from 3 months to 21 years. Radiological findings, treatment strategies, and clinical outcome were evaluated retrospectively and compared with literature. Forty (53.3%) patients were treated conservatively and 35 patients (47%) surgically using anterior or posterior approaches. Subgroup analysis was performed depending on age groups, severity of neurological symptoms, and localization. RESULTS: Main trauma mechanisms were fall in 24 patients (38%) and motor vehicle accidents in 21 patients (28%). Complete neurological deficits were present in 17 individuals (23%) and incomplete in 36 patients (48%). Fractures were most frequently localized at the cervical region (56%) with predilection of the C 5/6 segment. Odontoid fractures were seen in 10 (13%) patients. Fractures of the lumbar and thoracic region were rare. Level of injury or clinical course did not differ between the subgroups (≤15 years versus >15 years). CONCLUSION: Nearly three fourths of all radiologically detected spinal injuries are located at the cervical spine. Complete neurological deficits after trauma was associated with a poor outcome, in particular for patients with injuries of the upper cervical spine. The use of autologous bone graft was associated with favorable long-term results and should be considered as the material of first choice for vertebral body and disc replacement.

Cervical spondylodiscitis--a clinical analysis of surgically treated patients and review of the literature.

OBJECTIVE: The aim of this study was to analyze our clinical and neurological results of surgically treated patients suffering from cervical spondylodiscitis with focusing particularly on the surgical methods used and to review the literature. PATIENTS AND METHODS: We present a series of 21 patients operated with cervical spondylodiscitis between 1998 and 2011. Basic demographic data, comorbidities, the radiological segments involved, the surgical strategy with special consideration of the material used and the clinical outcome were evaluated retrospectively. RESULTS: The mean age of 6 female and 12 male patients was 65 years (range 28-89 years). The mean follow-up was 3.7 years ranging between 4 weeks and 9 years. The leading symptom was neurological deficits rather than pain. The segments C 5/6 (n=8) and C 6/7 (n=7) were most frequently involved. Different surgical methods depending on the location, anatomical and pathological condition and extension of the lesion were performed. CONCLUSION: In conclusion, cervical spondylodiscitis could effectively be treated in the presented patient cohort by surgical decompression, debridement and PMMA or bone graft implants followed by long term antibiotic therapy. The presented surgical reconstruction technique with PMMA might be a feasible alternative to the use of bone graft or cages. The promising clinical results warrant future prospective studies to further investigate this technique.

Elderly patients are at increased risk for mortality undergoing surgical repair of dens fractures.

OBJECTIVE: Dens fractures are common cervical injuries in advanced aged patients. The presented study was undertaken to analyze the clinical results and risks of surgically treated patients with dens fractures over 70 years. METHODS: Data of 28 patients (17 female, 11 male) over 70 years treated from September 2004 to October 2009 were recorded. Clinical and radiological parameters were obtained including type of fracture, associated cervical and/or other injuries, comorbidities, symptoms, neurological condition, surgical strategy, postoperative course and complications. RESULTS: 89% were in a good neurological condition before surgery (ASIA E or D). In most cases, surgery was performed at an early stage after trauma (21 patients within 5 days). Ventral screw fixation was the preferred surgical strategy (64%). A slight worsening of neurological functions immediately after operation was only seen in one patient. Five patients died in the early and 2 in the late postoperative course which means a treatment mortality of 25%. Among the surviving patients two had general medical complications. CONCLUSION: Type II dens fractures are a common fracture of elderly patients. Our results are good concerning the neurological functions. Surgical and general medical complications were acceptable. However, the study also underlines that mortality rate is high and therefore treatment options should be well-considered in this high risk group.

Intramedullary spinal cord astrocytomas: the influence of localization and tumor extension on resectability and functional outcome.

BACKGROUND: Intramedullary spinal cord tumors (IMSCT) are rare lesions, ependymomas and astrocytomas being the most common ones. Different studies have been published showing results of different treatment strategies as extensive/ limited surgery, biopsy and adjuvant radiation therapy with regard to functional outcome and survival. The present study was undertaken to analyse our series of surgically treated intramedullary astrocytomas in order to identify factors with impact on functional outcome and resectability. METHODS: Over a period of 20 years, among 215 patients with IMSCT 22 patients with astrocytomas were identified and enrolled into this analysis. Demographic data, clinical symptoms, localization and extension of the tumor, resection rate as well as pre- and postoperative neurological status were obtained. Patients were followed-up clinically and by MRI. RESULTS: Complete resection rate was higher in cervically located tumors (9 of 10) compared to non-cervical tumors (7 of 12). Tumor extension (1-3 segments vs. > 3 segments involved) did not influence on the resection rate. Cervical tumors showed a trend for better postoperative functional outcome than non-cervical lesions (3 of 10 cervical but 6 of 12 non-cervical tumors deteriorated postoperatively). In tumors extending more than 3 segments postoperative worsening was significantly increased. CONCLUSIONS: The present study shows a better resectability and functional outcome for cervically located intramedullary astrocytomas. Tumors extending more than three segments deteriorated significantly. These findings may help for decision-making process and treatment of these tumors.

Evaluation of new radiolucent polymer headholder pins for use in intraoperative computed tomography.

OBJECT: With the introduction of intraoperative CT (iCT) scanning, neurosurgeons can now obtain images of the brain during surgery, offering the possibility of intraoperative resection control and monitoring of potential intraoperative complications. The combination of iCT with neuronavigation makes it possible to update the reference scans intraoperatively when necessary. However, the headholder pins normally used for iCT scanning still show artifacts. In the present study, new polymer pins, producing nearly no artifacts in laboratory tests, are compared with the usual pins with regard to their mechanical and artifact behavior to evaluate their potential use in the clinical routine. METHODS: Pins made of different materials (titanium, Macor, silicon nitride, zirconium oxide, sapphire, polyetheretherketone, and polyparaphenylene copolymer) were used for the fixation of 10 cadaveric heads. Special force sensors measured the fixation pressure of the pins, and histological analysis revealed the penetration depth. Computed tomography scans of a head phantom, fixed with the different pins, were obtained to reveal artifact behavior. RESULTS: All pins were biocompatible. Pins did not differ significantly in fixation pressures and mechanical behavior. Penetration depths were comparable (maximum 1.4 mm) and did not cause opening of the diploe. Polymer pins made of polyparaphenylene showed the best results in artifact behavior in CT scans. CONCLUSIONS: The authors' results demonstrate that the new polymer pins are comparable in their mechanical behavior to the usual pins but superior in artifact behavior. Therefore, their use in the clinical routine of iCT scanning will be beneficial for the surgeon.

Multiple cerebral cavernous malformations associated with extracranial mesenchymal anomalies.

Cerebral cavernous malformations (CCM) are common hamartous dysplasias characterized by abnormally dilated vascular channels. CCM mostly occur sporadically, and multiple occurrence of CCM is highly suggestive of a genetic origin of the disorder. Typical clinical symptoms are seizures, hemorrhages, focal neurological deficits, and headaches. Three genes have so far been described that are responsible for most cases of familial CCM and more than half of the sporadic cases with multiple CCM (CCM1-3). The coincidence of CCM and other vascular anomalies has been described before. The present review discusses the association of CCM with mesenchymal anomalies, with special emphasis on the possible common pathogenetic pathway for CCM and atrial myxomas. An illustrative case is presented in which CCM occurred together with different dysplasias (multiple CCM, liver cavernoma, and cardiac atrial myxoma), which are all thought to arise from abnormal mesenchymal cell differentiation processes.

Microsurgical anatomy of the mesencephalic veins.

OBJECT: The mesencephalic veins drain crucial brainstem areas. Due to the narrowness of the tentorial notch, these veins can become obstructed as a result of herniation or surgery, leading to hemorrhage and severe consequences for the patient. There is little in the literature about the mesencephalic veins. The aim of this study was to perform an exact analysis of their microanatomy. METHODS: Fifty-two cadaveric hemispheres were examined under an operating microscope, and measurements were made with a digital caliper. The authors focused on the basal vein (BV), pontomesencephalic vein (PMV), peduncular vein (PV), lateral mesencephalic vein (LMV), and other smaller veins. The PMV was identified in 84.6% of specimens (mean diameter 0.54 mm); the PV, in 86.5% (mean diameter 0.86 mm); and the LMV, in 100% (mean diameter 1.07 mm). Four types of LMV were identified on the basis of the vein's course. Other smaller veins were also differentiated according to whether they drained mainly the cerebral peduncle, the lemniscal trigone, or the tectum. These veins and their junctions with other veins were depicted. CONCLUSIONS: A thorough understanding of the microanatomy of the mesencephalic veins is crucial in brainstem surgery in order to avoid brain damage due to venous infarction and subsequent edema. Because knowledge of the course, variations, and outflow system of these veins could improve surgical outcome, they warrant special attention during surgery.

Surgery of the anterior part of the frontal lobe and of the central region: normative morphometric data based on magnetic resonance imaging.

Modern magnetic resonance imaging (MRI) techniques have improved the planning of surgery to remove lesions in or around the frontal lobe. Since MRI-based morphometric analyses of the anterior part of the frontal lobe and the central region as part of it have not yet been performed, the present study was undertaken to obtain relative normative morphometric data. Median sagittal MRI scans from 53 magnetization prepared rapid acquisition gradient echo (MPRAGE) sequences of individual brains without pathological lesions were analyzed. The AC-PC line (anterior commissure-posterior commissure line) with vertical lines through the AC and PC were chosen as reference lines. Measurements of the anterior part of the frontal lobe included distances between different landmarks (frontal pole, tuberculum sellae, AC, outer point and inner surface of the genu of the corpus callosum, and the cortex at this level). For the measurements around the central region distances were obtained from the following landmarks: coronal suture, central sulcus, marginal sulcus, intersection point of the vertical line through the PC with the cortex, and PC. Knowledge of these distances will allow exact planning of surgical approaches to the anterior part of the frontal lobe, for example, the subfrontal or anterior interhemispheric approach and surgery around the central region.

Microsurgical anatomy of the lateral mesencephalic vein and its meaning for the deep venous outflow of the brain.

The cerebral venous outflow consists of the superficial system and the deep draining system. The deep one drains the areas of the great vein of Galen, the two basal veins of Rosenthal, and their tributaries. Simultaneous obstruction of these veins can effect great harm. In the case of obstruction of the vein of Galen, the basal vein can ensure the venous outflow. Therefore, attention should be paid to anastomoses between the basal vein and the infratentorial venous system. The lateral mesencephalic vein (LMV) is the most important anastomosis between the supra- and infratentorial system linking the basal vein to the superior petrosal sinus. Since microanatomical studies concerning this vein have received less attention the aim of the present study was to visualize the course of this vein, its junction with the basal vein, its tributaries and its relationship with neural structures. Fifty-two cadaveric hemispheres were examined under the operating microscope. The LMV could be identified in all cases, with a mean diameter of 1.07 mm. Thorough understanding of the microanatomy of the LMV is crucial to avoid brain damage due to venous infarction during surgery, and its preservation could ensure deep venous outflow in the case of obstruction of the vein of Galen.

Subtemporal approach to the tentorial incisura: normative morphometric data based on magnetic resonance imaging scans.

OBJECTIVE: The tentorial notch can be contained within a transversal line made in front of the cerebral peduncles and another line through the posterior border of the quadrigeminal plate into the anterior, middle and posterior parts. Different approaches to the tentorial incisura have been established. The subtemporal approach represents one of those options. Since morphometrical analyses of this approach in this region have not yet been performed, the aim of the present study was to measure the surgical corridor along these borders. METHODS: Fifty-three magnetization prepared rapid acquisition gradient echo-sequences of individual brains without pathological lesions were analyzed. For this study, an axial section along the pontomesencephalic sulcus and two coronal sections along the above-described borders were measured using a program specially written by one of the coauthors to obtain various parameters. A triangle circumscribing the surgical corridor was delimited by exactly defined anatomic landmarks for the coronal section, and the depths of the temporal lobe at the incisural borders were measured for the axial section. RESULTS: Various data are given concerning the surgical corridor of a subtemporal approach to the tentorial incisura. The different shapes of this corridor to the incisural region were recorded. According to our measurements, four different types of the temporal lobe could be differentiated. CONCLUSION: Knowledge of these distances and various contours of the path is crucial to avoid brain damage during retraction or manipulation. The curvature of the floor of the middle cranial fossa is highly variable and thus determines the surgical path chosen.