Working in low- and middle-income countries: Learning from each other.

•Barriers may limit LMICs-HICs collaborations: infrastructure, equipment's lack/inadequacy, political issues, brain drain.•Local training is crucial for universal health coverage; several activities are headed by Global Neurosurgery organisations.•The â€‹EANS Global and Humanitarian Neurosurgery Committee aims to become a gateway for partnerships between HICs and LMICs.

Need of vascular surgeon and comparison of value for anterior lumbar interbody fusion (ALIF) in lateral decubitus: Delphi consensus.

BACKGROUND AND PURPOSE: Anterior lumbar approaches are recommended for clinical conditions that require interbody stability, spinal deformity corrections or a large fusion area. Anterior lumbar interbody fusion in lateral decubitus position (LatALIF) has gained progressive interest in the last years. The study aims to describe the current habit, the perception of safety and the perceptions of need of vascular surgeons according to experienced spine surgeons by comparing LatALIF to the standard L5-S1 supine ALIF (SupALIF). METHODS: A two-round Delphi method study was conducted to assess the consensus, within expert spine surgeons, regarding the perception of safety, the preoperative planning, the complications management and the need for vascular surgeons by performing anterior approaches (SupALIF vs LatALIF). RESULTS: A total of 14 experts voluntary were involved in the survey. From 82 sentences voted in the first round, a consensus was reached for 38 items. This included the feasibility of safe LatALIF without systematic involvement of vascular surgeon for routine cases (while for revision cases the involvement of the vascular surgeon is an appropriate option) and the appropriateness of standard MRI to evaluate the accessibility of the vascular window. Thirteen sentences reached the final consensus in the second round, whereas no consensus was reached for the remaining 20 statements. CONCLUSIONS: The Delphi study collected the consensus on several points, such as the consolidated required experience on anterior approaches, the accurate study of vascular anatomy with MRI, the management of complications and the significant reduction of the surgical times of the LatALIF if compared to SupALIF in combined procedures. Furthermore, the study group agrees that LatALIF can be performed without the need for a vascular surgeon in routine cases.

Evaluation of Outcomes Among Patients With Traumatic Intracranial Hypertension Treated With Decompressive Craniectomy vs Standard Medical Care at 24 Months: A Secondary Analysis of the RESCUEicp Randomized Clinical Trial.

Importance: Trials often assess primary outcomes of traumatic brain injury at 6 months. Longer-term data are needed to assess outcomes for patients receiving surgical vs medical treatment for traumatic intracranial hypertension. Objective: To evaluate 24-month outcomes for patients with traumatic intracranial hypertension treated with decompressive craniectomy or standard medical care. Design, Setting, and Participants: Prespecified secondary analysis of the Randomized Evaluation of Surgery With Craniectomy for Uncontrollable Elevation of Intracranial Pressure (RESCUEicp) randomized clinical trial data was performed for patients with traumatic intracranial hypertension (>25 mm Hg) from 52 centers in 20 countries. Enrollment occurred between January 2004 and March 2014. Data were analyzed between 2018 and 2021. Eligibility criteria were age 10 to 65 years, traumatic brain injury (confirmed via computed tomography), intracranial pressure monitoring, and sustained and refractory elevated intracranial pressure for 1 to 12 hours despite pressure-controlling measures. Exclusion criteria were bilateral fixed and dilated pupils, bleeding diathesis, or unsurvivable injury. Interventions: Patients were randomly assigned 1:1 to receive a decompressive craniectomy with standard care (surgical group) or to ongoing medical treatment with the option to add barbiturate infusion (medical group). Main Outcomes and Measures: The primary outcome was measured with the 8-point Extended Glasgow Outcome Scale (1 indicates death and 8 denotes upper good recovery), and the 6- to 24-month outcome trajectory was examined. Results: This study enrolled 408 patients: 206 in the surgical group and 202 in the medical group. The mean (SD) age was 32.3 (13.2) and 34.8 (13.7) years, respectively, and the study population was predominantly male (165 [81.7%] and 156 [80.0%], respectively). At 24 months, patients in the surgical group had reduced mortality (61 [33.5%] vs 94 [54.0%]; absolute difference, -20.5 [95% CI, -30.8 to -10.2]) and higher rates of vegetative state (absolute difference, 4.3 [95% CI, 0.0 to 8.6]), lower or upper moderate disability (4.7 [-0.9 to 10.3] vs 2.8 [-4.2 to 9.8]), and lower or upper severe disability (2.2 [-5.4 to 9.8] vs 6.5 [1.8 to 11.2]; χ27 = 24.20, P = .001). For every 100 individuals treated surgically, 21 additional patients survived at 24 months; 4 were in a vegetative state, 2 had lower and 7 had upper severe disability, and 5 had lower and 3 had upper moderate disability, respectively. Rates of lower and upper good recovery were similar for the surgical and medical groups (20 [11.0%] vs 19 [10.9%]), and significant differences in net improvement (≥1 grade) were observed between 6 and 24 months (55 [30.0%] vs 25 [14.0%]; χ22 = 13.27, P = .001). Conclusions and Relevance: At 24 months, patients with surgically treated posttraumatic refractory intracranial hypertension had a sustained reduction in mortality and higher rates of vegetative state, severe disability, and moderate disability. Patients in the surgical group were more likely to improve over time vs patients in the medical group. Trial Registration: ISRCTN Identifier: 66202560.

SARS-CoV-2 Infection Induces Psoriatic Arthritis Flares and Enthesis Resident Plasmacytoid Dendritic Cell Type-1 Interferon Inhibition by JAK Antagonism Offer Novel Spondyloarthritis Pathogenesis Insights.

Objective: Bacterial and viral infectious triggers are linked to spondyloarthritis (SpA) including psoriatic arthritis (PsA) development, likely via dendritic cell activation. We investigated spinal entheseal plasmacytoid dendritic cells (pDCs) toll-like receptor (TLR)-7 and 9 activation and therapeutic modulation, including JAK inhibition. We also investigated if COVID-19 infection, a potent TLR-7 stimulator triggered PsA flares. Methods: Normal entheseal pDCs were characterized and stimulated with imiquimod and CpG oligodeoxynucleotides (ODN) to evaluate TNF and IFNα production. NanoString gene expression assay of total pDCs RNA was performed pre- and post- ODN stimulation. Pharmacological inhibition of induced IFNα protein was performed with Tofacitinib and PDE4 inhibition. The impact of SARS-CoV2 viral infection on PsA flares was evaluated. Results: CD45+HLA-DR+CD123+CD303+CD11c- entheseal pDCs were more numerous than blood pDCs (1.9 ± 0.8% vs 0.2 ± 0.07% of CD45+ cells, p=0.008) and showed inducible IFNα and TNF protein following ODN/imiquimod stimulation and were the sole entheseal IFNα producers. NanoString data identified 11 significantly upregulated differentially expressed genes (DEGs) including TNF in stimulated pDCs. Canonical pathway analysis revealed activation of dendritic cell maturation, NF-κB signaling, toll-like receptor signaling and JAK/STAT signaling pathways following ODN stimulation. Both tofacitinib and PDE4i strongly attenuated ODN induced IFNα. DAPSA scores elevations occurred in 18 PsA cases with SARS-CoV2 infection (9.7 ± 4 pre-infection and 35.3 ± 7.5 during infection). Conclusion: Entheseal pDCs link microbes to TNF/IFNα production. SARS-CoV-2 infection is associated with PsA Flares and JAK inhibition suppressed activated entheseal plasmacytoid dendritic Type-1 interferon responses as pointers towards a novel mechanism of PsA and SpA-related arthropathy.

Applied anatomy and surgical technique of the lateral single-position L5-S1 fusion.

The latest development in the anterior lumbar interbody fusion (ALIF) procedure is its application in the lateral position to allow for simultaneous posterior percutaneous screw placement. The technical details of the lateral ALIF technique have not yet been described. To describe the surgical anatomy relevant to the lateral ALIF approach we performed a comprehensive anatomical study. In addition, the preoperative imaging, patient positioning, planning of the skin incision, positioning of the C-arm, surgical approach, and surgical technique are discussed in detail. The technique described led to the successful use of the lateral ALIF technique in our clinical cases. No lateral ALIF procedure needed to be aborted during these cases. Our present work gives detailed anatomical background and technical details for the lateral ALIF approach. This teaching article can provide readers with sufficient technical and anatomical knowledge to assist them in performing their first lateral ALIF procedure.

S1 Sacrectomy for Re-recurrent Rectal Cancer: Our Experience with Reconstruction Using an Expandable Vertebral Body Replacement Device.

INTRODUCTION: R0 resection is achieved by high sacrectomy for local recurrence of colorectal cancer, but significant rates of perioperative complications and long-term patient morbidity are associated with this procedure. In this report, we outline our unique experience of using an expandable cage for vertebral body reconstruction following S1 sacrectomy in a 66-year-old patient with re-recurrent rectal cancer. We aim to highlight several key steps, with a view to improving postoperative outcomes. TECHNIQUE: A midline laparotomy was performed with the patient in supine Lloyd-Davies position, demonstrating recurrence of tumor at the S1 vertebral body. Subtotal vertebral body excision of S1 with sparing of the posterior wall and ventral foramina was completed by using an ultrasonic bone aspirator. Reconstruction was performed using an expandable corpectomy spacer system. The system was assembled and expanded in situ to optimally bridge the corpectomy. The device was secured into the L5 and S2 vertebrae by means of angled end plate screws superiorly and inferiorly. Bone grafts were positioned adjacent to the implant after this. RESULTS: Total operating time was 266 minutes with 350 mL of intraoperative blood loss. There were no immediate postoperative complications. The patient did not report any back pain at the time of discharge, and no neurological deficit was reported or identified. Postoperative CT scan showed excellent vertebral alignment and preservation of S1 height. CONCLUSION: We conclude that high sacrectomy with an expandable metal cage is feasible in the context of re-recurrent rectal cancer when consideration is given to the method of osteotomy and vertebral body replacement.

Cadaveric Spinal Surgery Simulation: A Comparison of Cadaver Types.

Study Design Single-blinded study. Objective To assess the suitability of three types of cadaver for simulating pedicle screw insertion and establish if there is an ideal. Methods Three types of cadaver-Thiel-embalmed, Crosado-embalmed, and formaldehyde-embalmed-were draped and the spines exposed. Experienced surgeons were asked to place pedicle screws in each cadaver and give written questionnaire feedback using a modified Likert scale. Soft tissue and bony properties were assessed, along with the role of simulation in spinal surgery training. Results The Thiel cadaver rated highest for soft tissue feel and appearance with a median score of 6 for both (range 2 to 7). The Crosado cadaver rated highest for bony feel, with a median score of 6 (range 2 to 7). The formaldehyde cadaver rated lowest for all categories with median scores of 2, 2.5, and 3.5, respectively. All surgeons felt pedicle screw insertion should be learned in a simulated setting using human cadavers. Conclusion Thiel and Crosado cadavers both offered lifelike simulation of pedicle screw insertion, with each having advantages depending on whether the focus is on soft tissue approach or technical aspects of bony screw insertion. Both cadaver types offer the advantage of long life span, unlike fresh frozen tissue, which means cadavers can be used multiple times, thus reducing the costs.

En bloc resection of a thoracic chordoma is possible using minimally invasive anterior access: An 8-year follow-up.

Thoracic spine chordomas are a rare clinical entity and present several diagnostic and management challenges. Posterior debulking techniques are the traditional approach for the resection of thoracic tumors involving the vertebral body. Anterior approaches to the thoracic spine enable complete tumor resection and interbody fusion. However, this approach has previously required a thoracotomy incision, which is associated with significant perioperative morbidity, pain, and the potential for compromised ventilation and subsequent respiratory sequelae. The extreme lateral approach to the anterior spine has been used to treat degenerative disorders of the lower thoracic and lumbar spine, and reduces the potential complications compared with the anterior transperitoneal/transpleural approach. However, such an approach has not been utilized in the treatment of thoracic chordomas. We describe the first case of an en bloc resection of a thoracic chordoma via a minimally invasive eXtreme lateral interbody fusion approach.

Anterior cervical discectomy and fusion versus posterior cervical foraminotomy in the treatment of brachialgia: the Leeds spinal unit experience (2008-2013).

BACKGROUND: The surgical management of cervical brachialgia utilising anterior cervical discectomy and fusion (ACDF) or posterior cervical foraminotomy (PCF) is a controversial area in spinal surgery. Previous studies are limited by utilisation of non-validated outcome measures and, importantly, absence of pre-operative analysis to ensure both groups are matched. The authors aimed to compare the effectiveness of ACDF and PCF using validated outcome measures. To our knowledge, it is the first study in the literature to do this. METHODS: The authors conducted a 5-year retrospective review (2008-2013) of outcomes following both the above procedures and also compared the effectiveness of both techniques. Patients with myelopathy and large central discs were excluded. The main outcome variables measured were the neck disability index (NDI) and visual analogue scores (VAS) for neck and arm pain pre-operatively and again at 2-year follow-up. The Wilcoxon signed-rank test and Student t-tests were used to test differences. RESULTS: A total of 150 ACDFs and 51 PCFs were performed for brachialgia. There was no differences in the pre-operative NDI, VAS neck and arm scores between both groups (p > 0.05). As expected, both ACDF and PCF delivered statistically significant improvement in NDI, VAS-neck and VAS-arm scores. The degree of improvement of NDI, VAS-neck and VAS-arm were the same between both groups of patients (p > 0.05) with a trend favouring the PCF group. In the ACDF group, two (1.3 %) patients needed repeat ACDF due to adjacent segment disease. One patient (0.7 %) needed further decompression via a foraminotomy. In the PCF group one (2.0 %) patient needed ACDF due to persistent brachialgia. CONCLUSIONS: We found both interventions delivered similar improvements in the VAS and NDI scores in patients. Both techniques may be appropriately utilised when treating a patient with cervical brachialgia.

Extent of medicolegal burden in neurosurgery - An analysis of the National Health Service Litigation Authority Database.

INTRODUCTION: Neurosurgery remains amongst the highest malpractice risk specialties. We aimed to better understand the medicolegal burden in neurosurgery by analysing a large volume of claims recorded by the National Health Service Litigation Authority (NHSLA). METHODS: The NHSLA database was retrospectively interrogated for all closed (i.e. with legal outcomes) claims in neurosurgery recorded between 1997 and 2011. Collected data included clinical event; subspecialty; patient injury sustained; reason for claim; legal outcome and litigation costs. RESULTS: The total neurosurgical litigation cost associated with 617 closed claims over the time period investigated was £67.4 million. 282 claims (46%) were successful with damages awarded. The annual claim volume and damages paid increased between 2002 and 2011 by 50% and 140%, respectively, and two-thirds of these increases were attributable to spinal claims. 30% of the total litigation cost was legal fees. The leading causes of damages paid in cranial surgery were delayed diagnosis (29%) and delayed treatment (24%). In contrast, the leading causes of damages paid in spinal surgery were delayed diagnosis (32%) and surgical negligence (22%). The greatest mean damages awarded per claim were for brain damage (£617,000), compared to only £51,000 for fatality. CONCLUSION: Neurosurgical litigation in NHS hospitals has significantly increased over the last decade, predominantly due to spinal claims. A neurosurgical claim has a very high likelihood of success, and even for unsuccessful claims, associated legal fees are considerable. Causes of claims are differently distributed between cranial and spinal neurosurgery, although overall, delay to diagnosis accounted for the predominant share of claims volume and damages. There was a significant medicolegal burden associated with serious long-term injury and need for life-long care as in the case of brain damage as compared with death as an outcome. This analysis represents the largest U.K. study on litigation in surgery to date.

Comparison of vertebroplasty using directional versus straight needle.

BACKGROUND: Percutaneous vertebroplasty is a minimally invasive procedure that can be performed to treat pain and immobility associated with vertebral compression fractures. Previous studies have shown that a single injection can achieve adequate fill across the midline of the vertebral body. PURPOSE: To compare the radiological outcomes of using a novel steerable needle with using a conventional, straight needle in unipedicular vertebroplasty. MATERIAL AND METHODS: Data were collected from 19 patients who were operated at our institute between 1 September 2010 and 31 March 2011. Outcomes were measured in terms of radiological evidence of midline crossing of cement. The available pre- and postoperative pain scores and complications were reviewed. Student's t-test was used to compare mean cement projection across the midline in both groups with P < 0.05 considered to be statistically significant. RESULTS: Mean fill across the midline was significantly greater with the steerable needle (58%) compared with the straight needle (35%) (P = 0.046). Cement leakage was higher with the steerable needle (44% versus 30%); however no clinical complications were reported in either group. CONCLUSION: Percutaneous vertebroplasty using a directional needle is an excellent example of advancement and refinement in spinal surgery without increased clinical risk. Our results indicate that the novel technique can potentially provide better radiological outcomes when compared with a straight needle. A larger, randomized multicenter prospective trial would be valuable in confirming these findings.

Neurosurgical patties: adhesion and damage mitigation.

OBJECT: Neurosurgical patties are textile pads used during most neurosurgical operations to protect tissues, manage the fluid environment, control hemostasis, and aid tissue manipulation. Recent research has suggested that, contrary to their aim, patties adhere to brain tissue and cause damage during removal. This study aimed to characterize and quantify the degree of and consequences resulting from adhesion between neurosurgical patties and brain tissue. METHODS: Using a customized peel apparatus, the authors performed 90° peel tests on 5 patty products: Policot, Telfa, Americot, Delicot, and Ray-Cot (n = 247) from American Surgical Company. They tested 4 conditions: wet patty on glass (control), wet patty on wet brain peeled at 5 mm/sec (wet), dry patty on wet brain peeled at 5 mm/sec (dry), and wet patty on wet brain peeled at 20 mm/sec (speed). The interaction between patty and tissue was analyzed using peel-force traces and pre-peel histological analysis. RESULTS: Adhesion strength differed between patty products (p < 0.001) and conditions (p < 0.001). Adhesion strength was greatest for Delicot patties under wet (2.22 mN/mm) and dry (9.88 mN/mm) conditions. For all patties, damage at the patty-tissue interface was proportional to the degree of fiber contact. When patties were irrigated, mechanical adhesion was reduced by up to 550% compared with dry usage. CONCLUSIONS: For all patty products, mechanical (destructive) and liquid-mediated (nondestructive) adhesion caused damage to neural tissue. The greatest adhesion occurred with Delicot patties. To mitigate patty adhesion and neural tissue damage, surgeons should consider regular irrigation to be essential during neurosurgical procedures.

Fracture through fused cervical segments following trauma in a patient with Klippel-Feil syndrome.

Klippel-Feil syndrome (KPS) is a congenital spinal deformity characterised by the presence of at least one fused cervical segment. We report an unusual case of a fracture through fused cervical segment in a patient with KPS, who presented with quadriparesis and progressed on to develop respiratory failure and quadriplegia and who had a successful outcome following surgery. To the best of our knowledge, fracture through fused cervical segments in a Klippel-Feil patient has not been reported previously and this case report extends the spectrum of injuries seen in patients with KPS.

Retrieval of a migrated AxiaLIF lumbosacral screw using fluoroscopic guidance with simultaneous real-time sigmoidoscopy: technical report.

STUDY DESIGN: Technical report. OBJECTIVE: This article describes the technique of using intraoperative sigmoidoscopy as an adjunct for retrieval of the AxiaLIF lumbosacral screw after failure of lumbar fusion. SUMMARY OF BACKGROUND DATA: Minimally invasive axial lumbar interbody fusion devices have emerged during the past 3 years as an alternative to traditional surgery for the treatment of intractable back pain. No reports of inferior migration of the lumbosacral screw causing rectal symptoms have been previously described. A 32-year-old firefighter with intractable lumbar back pain was treated with minimally invasive axial lumbar interbody fusion with L4-S1 pedicle screw fixation. Sequential images obtained for more than 18 months demonstrated loosening and migration of the axial screw 3.5 cm inferiorly causing impression on the rectum and symptoms of tenesmus. METHODS: Preoperative sigmoidoscopy was performed to exclude rectal perforation. During retrieval of the lumbosacral screw, simultaneous sigmoidoscopy was performed to ensure the rectum was not damaged. RESULTS: The lumbosacral screw was successfully removed using a presacral approach. The patient's rectal symptoms improved postoperatively, and was discharged after 48 hours. CONCLUSION: For the retrieval of migrated AxiaLIF lumbosacral screws, intraoperative sigmoidoscopy is technically feasible and serves as a useful adjunct to ensure the integrity of the rectal mucosa is maintained. This technique can be used to avoid the potential morbidity of rectal perforation, and subsequent laparotomy and defunctioning colostomy. LEVEL OF EVIDENCE: N/A.

Interspinous distractor devices for the management of lumbar spinal stenosis: a miracle cure for a common problem?

Neurogenic claudication due to lumbar spinal stenosis is the commonest cause of back and leg pain in the elderly. It consumes large amounts of healthcare resource and is a common reason for GP consultations. Surgical management by decompressive laminectomy is the traditional method used for those patients in whom conservative management has failed. However, the advent of minimally invasive interspinous distraction devices, which are designed to alleviate symptoms of neurogenic intermittent claudication without subjecting the patient to a major operation, has potentially revolutionised the management of lumbar spinal stenosis. This review describes the principles of interspinous distraction devices, the rationale for their use in the management of lumbar spinal stenosis, indications and predictors of outcome. Published data on the safety and efficacy of the various devices available is encouraging but long term results are awaited. The superiority of interspinous distraction devices over conservative treatment has already been established, however, the precise indication for this new technology and whether the implants can replace conventional decompressive surgery in some situations has not been clearly defined.

Motion preservation and clinical outcome of porous coated motion cervical disk arthroplasty.

BACKGROUND: Artificial cervical disk replacements are commonly used to treat radiculomyelopathy caused by degenerative disk disease. However, long-term disk mobility and an effect on adjacent segment disease have yet to be demonstrated. We report improvements in clinical outcome after disk replacement but also demonstrate potential limitations. OBJECTIVE: To review clinical and radiological outcomes after diskectomy and disk replacement with the Porous Coated Motion (PCM) artificial cervical disk. METHODS: A retrospective review was done of consecutive patients who underwent 1- or 2-level PCM disk replacements. The following criteria were studied: arm pain, neck pain, Neck Disability Index and Short Form-36 questionnaires, and flexion-extension radiographs up to 2 years after surgery. RESULTS: Eighty PCM artificial disks were implanted in 53 patients. Only 17 disks (21%) maintained physiological movement, and complete fusion was seen in 18.8%. One disk replacement was revised because of anterior displacement. There were no complications of infection, cerebrospinal fluid leak, dysphagia, or hoarse voice. Arm and neck pain improved significantly after diskectomy, but Neck Disability Index questionnaires demonstrated a slight improvement that was not sustained by 2 years. Short Form-36 scores demonstrated a trend toward better outcome with time, but it was significant only for the mental domain. CONCLUSION: Clinical improvement was seen after PCM disk replacement, but adequate range of movement was sustained in only 21% of disk replacements over time. Unclear long-term results of this and other disk replacements suggest caution in adopting these new devices as the gold standard.

Preliminary biomechanical evaluation of prophylactic vertebral reinforcement adjacent to vertebroplasty under cyclic loading.

BACKGROUND CONTEXT: Percutaneous vertebroplasty has become a favored treatment option for reducing pain in osteoporotic patients with vertebral compression fractures (VCFs). Short-term results are promising, although longer-term complications may arise from accelerated failure of the adjacent vertebral body. PURPOSE: To provide a preliminary biomechanical assessment of prophylactic vertebral reinforcement adjacent to vertebroplasty using a three-vertebra cadaveric segment under dynamic loads that represent increasing activity demands. In addition, the effects of reducing the elastic modulus of the cement used in the intact vertebrae were also assessed. STUDY DESIGN/SETTING: Three-vertebra cadaveric segments were used to evaluate vertebroplasty with adjacent vertebral reinforcement as an intervention for VCFs. METHODS: Nine human three-vertebra segments (T12-L2) were prepared and a compression fracture was generated in the superior vertebrae. Vertebroplasty was performed on the fractured T12 vertebra. Subsequently, the adjacent intact L1 vertebra was prophylactically augmented with cement of differing elastic moduli (100-12.5% modulus of the base cement value). After subfailure quasi-static compression tests before and after augmentation, these specimens were subjected to an incrementally increasing dynamic load profile in proportion to patient body weight (BW) to assess the fatigue properties of the construct. Quantitative computed tomography assessments were conducted at several stages in the experimental process to evaluate the vertebral condition and quantify the gross dimensions of the segment. RESULTS: No significant difference in construct stiffness was found pre- or postaugmentation (t=1.4, p=.19). Displacement plots recorded during dynamic loading showed little evidence of fracture under normal physiological loads or moderate activity (1-2.5x BW). A third of the specimens continued to endure increasing load demands and were confirmed to have no fracture after testing. In six specimens, however, greater loads induced 11 fractures: 7 in the augmented vertebra (2xT12, 5xL5) and 4 in the adjacent L2 vertebra. A strong correlation was observed between the subsidence in the segmental unit and the incidence of fracture after testing (r(Spearman's)=-0.88, p=.002). Altering the modulus of cement in the intact vertebra had no effect on level of segmental compromise. CONCLUSIONS: These preliminary findings suggest that under normal physiological loads associated with moderate physical activity, prophylactic augmentation adjacent to vertebroplasty showed little evidence of inducing fractures, although loads representing more strenuous activities may generate adjacent and peri-augmentation compromise. Reducing the elastic modulus of the cement in the adjacent intact vertebrae appeared to have no significant effect on the incidence or location of the induced fracture or the overall height loss of the vertebral segment.

The biomechanics of vertebroplasty in multiple myeloma and metastatic bladder cancer: a preliminary cadaveric investigation.

OBJECT: The vertebral column is the most common site for secondary bone metastases and lesions arising from hematological malignancies such as multiple myeloma (MM). These infiltrations can be lytic in nature and cause severe weakening of the vertebral body, an increased risk of fracture, and spinal cord compression leading to neurological deficit. Qualitatively it is apparent that increasing infiltration of these lytic lesions will have a deleterious effect on the mechanical behavior of the vertebrae. However, there is little quantitative information about the relationship between tumor deposits and the impact on the mechanical behavior of the vertebrae. In addition, there have been limited biomechanical assessments of the use of vertebroplasty in the management of these malignancies. The purpose of this preliminary study was to evaluate the mechanical behavior of lesion-infiltrated vertebrae from 2 malignant cancers and to investigate the effectiveness of vertebroplasty with and without tumor debulking. METHODS: Individual vertebrae from 2 donor spines--one with MM and another with bone metastases secondary to bladder cancer-were fractured under an eccentric flexion load, from which failure strength and stiffness were derived. Alternate vertebrae defined by spinal level were assigned to 2 groups: Group 1 involved removal of lesion material with Coblation (ArthroCare Corp.) preceding vertebroplasty; Group 2 received no Coblation prior to augmentation. All vertebrae were fractured postaugmentation under the same loading protocol. Micro-CT assessments were undertaken to investigate vertebral morphology, fracture patterns, and cement distribution. RESULTS: Multiple myeloma involvement was characterized by several small lesions, severe bone degradation, and multiple areas of vertebral shell compromise. In contrast, large focal lesions were present in the vertebrae with metastatic bladder cancer, and the shell generally remained intact. The mean initial failure strength of the vertebrae with metastases secondary to MM was significantly lower than in vertebrae with bone metastases secondary to bladder cancer (Load = 950 +/- 300 N vs 2200 +/- 750 N, p < 0.0001). A significant improvement in relative fracture strength was found postaugmentation for both lesion types (1.4 +/- 0.5, p < 0.001). Coblation provided a marginally significant increase in the same parameter postaugmentation (p = 0.08) and qualitatively improved the ease of injection and guidance of cement. CONCLUSIONS: In the vertebral column, metastatic lesions secondary to bladder cancer and MM showed variations in the pattern of infiltration, both of which led to significant reductions in fracture strength. Account should be taken of these differences to optimize the vertebroplasty intervention in terms of the cement formulation, delivery, and any additional surgical procedure.

Bradycardia in neurosurgery.

Cushing reflex' is characterized by the occurrence of hypertension, bradycardia and apnoea secondary to raised increased intracranial pressure (ICP), leading to pressure on and or stretch, or both, of the brainstem. With the wide availability of monitoring facilities and advancements in investigation techniques, observation of increased intracranial pressure resulting in haemodynamic instability and bradycardia has been increasingly recognized in relation to many neurosurgical conditions and procedures. The causes of bradycardia include space occupying lesion involving or compressing the brain parenchyma (subdural haematoma, tumours, hydrocephalus), neurosurgical procedures (neuroendoscopy, placement of extradural drains), epileptic and non-epileptic seizures, trigemino-cardiac reflex, cerebellar lesions, spinal lesions (neurogenic shock, autonomic dysreflexia) and many other rare causes (Ventricular catheter obstruction in cases of hydrocephalus, colloid cysts related acute neurogenic cardiac dysfunction, Ondine's curse syndrome, etc.). This highlights that bradycardia can be a warning sign in many neurosurgical conditions and Cushing's reflex is a protective and effective action of the brain for preserving an adequate cerebral perfusion pressure despite an increased intracranial pressure. Management of these patients include identification and treatment of the underlying cause of bradycardia, anti-cholinergics and if necessary cardiac pacing, nevertheless, other causes of haemodynamic changes (i.e. anesthetic drugs, tumor manipulation) should also be considered and managed accordingly. We believe that this knowledge and understanding will help to identify the patients' at risk and will also help in the management of neurosurgical patients with bradycardia.