Acute post-traumatic stress symptoms and age predict outcome in military blast concussion.

High rates of adverse outcomes have been reported following blast-related concussive traumatic brain injury in US military personnel, but the extent to which such adverse outcomes can be predicted acutely after injury is unknown. We performed a prospective, observational study of US military personnel with blast-related concussive traumatic brain injury (n = 38) and controls (n = 34) enrolled between March and September 2012. Importantly all subjects returned to duty and did not require evacuation. Subjects were evaluated acutely 0-7 days after injury at two sites in Afghanistan and again 6-12 months later in the United States. Acute assessments revealed heightened post-concussive, post-traumatic stress, and depressive symptoms along with worse cognitive performance in subjects with traumatic brain injury. At 6-12 months follow-up, 63% of subjects with traumatic brain injury and 20% of controls had moderate overall disability. Subjects with traumatic brain injury showed more severe neurobehavioural, post-traumatic stress and depression symptoms along with more frequent cognitive performance deficits and more substantial headache impairment than control subjects. Logistic regression modelling using only acute measures identified that a diagnosis of traumatic brain injury, older age, and more severe post-traumatic stress symptoms provided a good prediction of later adverse global outcomes (area under the receiver-operating characteristic curve = 0.84). Thus, US military personnel with concussive blast-related traumatic brain injury in Afghanistan who returned to duty still fared quite poorly on many clinical outcome measures 6-12 months after injury. Poor global outcome seems to be largely driven by psychological health measures, age, and traumatic brain injury status. The effects of early interventions and longer term implications of these findings are unknown.

Auricular Vagus Nerve Stimulation Mitigates Inflammation and Vasospasm in Subarachnoid Hemorrhage: A Randomized Trial.

Background: Inflammation contributes to morbidity following subarachnoid hemorrhage (SAH). Transauricular vagus nerve stimulation (taVNS) offers a noninvasive approach to target the inflammatory response following SAH. Methods: In this prospective, triple-blinded, randomized, controlled trial, twenty-seven patients were randomized to taVNS or sham stimulation. Blood and cerebrospinal fluid (CSF) were collected to quantify inflammatory markers. Cerebral vasospasm severity and functional outcomes (modified Rankin Scale, mRS) were analyzed. Results: No adverse events occurred. Radiographic vasospasm was significantly reduced (p = 0.018), with serial vessel caliber measurements demonstrating a more rapid return to normal than sham (p < 0.001). In the taVNS group, TNF-α was significantly reduced in both plasma (days 7 and 10) and CSF (day 13); IL-6 was also significantly reduced in plasma (day 4) and CSF (day 13) (p < 0.05). Patients receiving taVNS had higher rates of favorable outcomes at discharge (38.4% vs 21.4%) and first follow-up (76.9% vs 57.1%), with significant improvement from admission to first follow-up (p = 0.014), unlike the sham group (p = 0.18). The taVNS group had a significantly lower rate of discharge to skilled nursing facility or hospice (p = 0.04). Conclusion: taVNS is a non-invasive method of neuro- and systemic immunomodulation. This trial supports that taVNS following SAH can mitigate the inflammatory response, reduce radiographic vasospasm, and potentially improve functional and neurological outcomes. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04557618.

First-Line Stent Retriever versus Direct Aspiration for Acute Basilar Artery Occlusions: A Systematic Review and Meta-analysis.

BACKGROUND: Mechanical thrombectomy (MT) for anterior circulation stroke has been proven to be highly effective. In comparison, MT for basilar artery occlusion (BAO) continues to lack definitive evidence of efficacy. The main MT modalities are stent retriever (SR) and direct aspiration (DA). Several studies have been published comparing the 2 approaches. OBJECTIVE: We sought to directly compare and synthesize safety and efficacy outcomes with SR versus DA for acute BAO. METHODS: A systematic review and meta-analysis was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RESULTS: Overall, 8 studies comprising 693 patients with BAO were included (SR: 457; DA: 236). The SR group was associated with statistically significant lower odds of modified Thrombolysis in Cerebral Infarction (mTICI) 2b/3 (odds ratio [OR]: 0.54; 95% confidence interval [CI]: 0.31-0.94) and mTICI3 (OR: 0.47; 95% CI: 0.23-0.95) compared with DA. Favorable outcome rates were similar between the 2 groups (OR: 0.83; 95% CI: 0.60-1.16). The rates of symptomatic intracerebral hemorrhage (OR: 3.57; 95% CI: 0.75-16.95), subarachnoid hemorrhage (SAH) (OR: 4.71; 95% CI: 0.82-26.90), and vessel perforation (OR: 2.64; 95% CI: 0.43-16.33) were higher in the SR group, but statistical significance was not reached. The rates of 90-day mortality were similar between the 2 groups (OR: 1.07; 95% CI: 0.67-1.70). Procedure duration was significantly shorter when DA was used compared with SR (weighted mean difference: 26.10 minutes; 95% CI: 13.28-38.92). CONCLUSIONS: SR is associated with statistically significant lower odds of mTICI 2b/3 and mTICI 3 recanalization rates compared with DA. SR appears to be associated with a higher complication rate, but significance was not reached.

Carotid cavernous fistula (CCF) treatment approaches: A systematic literature review and meta-analysis of transarterial and transvenous embolization for direct and indirect CCFs.

BACKGROUND: Carotid Cavernous Fistulas (CCFs) are the result of an abnormal communication between the carotid artery and its branches and the venous system of the cavernous sinus. The mainstay of therapy for CCFs consists of transarterial or transvenous embolization, while other treatment options such as open surgery or radiosurgery are still utilized as second-line or adjuvant therapeutic options. OBJECTIVE: Our aim was to systematically review and summarize available data regarding short- and long-term outcomes of all available treatment modalities for CCFs. METHODS: This systematic review was conducted according to the PRISMA guidelines. A random effects model meta-analysis was conducted. RESULTS: Fifty-seven studies comprising 1575 patients were included in this systematic review. Transarterial embolization for direct and indirect CCFs offered a complete obliteration rate of 93.93% (N = 589/627) and 81.51% (N = 119/146), respectively. Transvenous embolization for direct and indirect lesions achieved obliteration in 91.67% (N = 33/36) and 86.03% (N = 425/494) of patients, respectively. Comparison between transarterial and transvenous embolization did not reveal statistically significant differences in terms of fistula obliteration for direct (OR: 1.42; 95% CI: 0.23-8.90; I2 0.0%) and indirect CCFs (OR: 0.62; 95% CI: 0.31-1.23; I2 0.0%). CONCLUSIONS: Endovascular embolization techniques are the preferred treatment modality for the management of CCFs. No differences were identified between transarterial and transvenous embolization by synthesizing studies with available data. Future prospective cohorts are warranted to compare the different materials and techniques implemented especially within the rapidly expanding realm of endovascular approaches.

A Consensus Study: Generational Differences in Neurosurgeons' Perception of Retirement and Practice Limits.

BACKGROUND: Concerns about the changing demographics in the United States and the aging of the neurosurgical workforce exist. Both the importance and inherent risk of surgical responsibilities suggest that thought be given to whether workloads should change later in surgeons' careers. We sought to assess current neurosurgeons' expectations concerning their late-stage careers. METHODS: A survey was sent to 3317 U.S. board-certified neurosurgeons. It was designed to assess surgeons' perceptions of call and operative responsibilities in the later stages of their careers. Statistical analyses were completed in R version 3.6.1, with an alpha set to 0.05. RESULTS: Six-hundred and fifty-nine neurosurgeons completed the questionnaire. Seventy-seven percent believed that the call burden should decrease later in practice, and 66% planned to decrease their own call burden later in their career. The most common age range for planned retirement was 65 to 69 years (36%), followed by 70+ years (33%). Most (67%) believed that there should not be a mandatory age to stop operating. More recent year of residency completion was negatively associated with the belief that call burden should decrease at older age groups and positively associated with support for a mandatory age to stop operating as well as an earlier retirement age. CONCLUSIONS: This study suggests that neurosurgeons have differing views on how workloads should change later in their careers. Younger neurosurgeons support an earlier decrease in workload or even a policy-mandated stop to operating after a certain age. These results may give insight into future trends and turnover in neurosurgery and provide a valuable tool to help practices anticipate workforce changes.

Mechanical Thrombectomy in Acute Ischemic Stroke: A Meta-Analysis of Stent Retrievers vs Direct Aspiration vs a Combined Approach.

BACKGROUND: Recent randomized control trials (RCTs) established that mechanical thrombectomy is superior to medical therapy for patients with stroke due to a large vessel occlusion. OBJECTIVE: To compare the safety and efficacy profile of the different mechanical thrombectomy strategies. METHODS: A random-effects meta-analysis was performed and the I2 statistic was used to assess heterogeneity according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RESULTS: Nineteen studies with a total of 2449 patients were included. No differences were identified between the stent retrieval and direct aspiration groups in terms of modified Thrombolysis in Cerebral Infarction (mTICI) 2b/3 and mTICI 3 recanalization rates, and favorable outcomes (modified Rankin Scale [mRS] ≤ 2). Adverse event rates, including 90-d mortality, symptomatic intracerebral hemorrhage (sICH), and subarachnoid hemorrhage (SAH), were similar between the stent retrieval and direct aspiration groups. The use of the stent retrieval was associated with a higher risk of vasospasm (odds ratio [OR]: 2.98; 95% confidence interval [CI]: 1.10-8.09; I2: 0%) compared to direct aspiration. When compared with the direct aspiration group, the subgroup of patients who underwent thrombectomy with the combined approach as a first-line strategy had a higher likelihood of successful mTICI 2b/3 (OR: 1.47; 95% CI: 1.02-2.12; I2: 0%) and mTICI 3 recanalization (OR: 3.65; 95% CI: 1.56-8.54), although with a higher risk of SAH (OR: 4.33; 95% CI: 1.15-16.32). CONCLUSION: Stent retrieval thrombectomy and direct aspiration did not show significant differences. Current available evidence is not sufficient to draw conclusions on the best surgical approach. The combined use of a stent retriever and aspiration as a first-line strategy was associated with higher mTICI 2b/3 and mTICI 3 recanalization rates, although with a higher risk of 24-h SAH, when compared with direct aspiration.

Prevalence of carotid stenosis following radiotherapy for head and neck cancer: A systematic review and meta-analysis.

BACKGROUND: Radiation to the head and neck is a well-established risk factor for the development of carotid artery stenosis. Our objective was to identify the prevalence, incidence, and degree of carotid stenosis in patients with a history of head and neck irradiation. METHODS: This study was performed according to the PRISMA guidelines. A random effects model meta-analysis was conducted. RESULTS: Nineteen studies comprising 1479 patients were included. The prevalence of carotid stenosis >50%, >70%, and carotid occlusion was 25% (95% CI: 19%-32%), 12% (95% CI: 7%-17%), and 4% (95% CI: 2%-8%), respectively. The cumulative 12-month incidence of carotid stenosis >50% was 4% (95% CI: 2%-5%), the 24-month was 12% (95% CI: 9%-15%), and the 36-month was 21% (95% CI: 9%-36%). CONCLUSIONS: The yearly incidence of carotid stenosis >50% increased every year during the first 3 years following radiotherapy. We propose routine yearly Doppler ultrasound screening beginning 1 year after head and neck radiotherapy.

Neurologic Complications in Patients with Left Ventricular Assist Devices: Single Institution Retrospective Review.

BACKGROUND: Neurologic complications are common complications encountered by patients with left ventricular assist devices (LVADs). This single-center retrospective study aims to identify the incidence and risk factors of neurologic complications and interventions in patients supported with LVADs and define the associated anticoagulation management. METHODS: Between August 2009 and August 2017, 244 patients underwent LVAD implantation. Twenty-one patients were excluded for having neurologic complications before LVAD placement or for having previously undergone heart transplantation. RESULTS: Fifty-six patients (25%) suffered 61 complications, and 11 (19.6%) died as a result. Gender, type of LVAD, or chronic medical comorbidities evaluated did not contribute to a difference in complication rate; in contrast, length of LVAD implantation was directly related to risk of neurologic complication. Eleven patients (19.6%) underwent 13 surgical interventions including 5 mechanical thrombectomies. Anticoagulation was reversed in 16 patients and held without complication. Anticoagulation was not held for ischemic complications, and no clinically significant hemorrhagic transformation occurred. Intravenous tissue plasminogen activator was also successfully administered to 3 patients without complication. CONCLUSIONS: Neurologic complications were observed in 25% of patients supported with LVADs, of which 20% required neurosurgical intervention. Anticoagulation can be safely withheld in patients with hemorrhagic complications. Patients with ischemic complications can continue to be anticoagulated with no significant risk of hemorrhagic transformation. Length of LVAD implantation was directly related to the risk of neurologic complication. Finally, our study adds to existing literature that mechanical thrombectomy and even intravenous tissue plasminogen activator are options for LVAD patients with ischemic complications.

Risk Factors for Restenosis After Carotid Revascularization: A Meta-Analysis of Hazard Ratios.

BACKGROUND: Carotid artery restenosis after carotid endarterectomy (CEA) or carotid artery stenting (CAS) will occur in 3%-30% of cases. Restenosis can lead to more frequent clinical and imaging monitoring and the potential for reoperation. We sought to define the demographic, clinical, and radiographic characteristics that influence the restenosis risk after carotid revascularization. METHODS: The present study was performed in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. A random effects model meta-analysis of hazard ratios (HRs) was conducted. RESULTS: Eighteen studies with 17,106 patients were included. Diabetes (HR, 1.68; 95% confidence interval [CI], 1.00-2.83; I2, 76.7%), dyslipidemia (HR, 1.77; 95% CI, 1.08-2.91; I2, 22.5%), female gender (HR, 1.50; 95% CI, 1.14-1.98, I2, 0%), chronic kidney disease (HR, 4.15; 95% CI, 1.69-10.19; I2, 44.5%), hypertension (HR, 1.99; 95% CI, 1.07-3.72; I2, 68%), smoking (HR, 1.65; 95% CI, 1.15-2.37; I2, 54.3%), and pretreatment stenosis >70% (HR, 1.04; 95% CI, 1.0-1.08; I2, 0%) showed a statistically significant increase in restenosis risk after carotid revascularization. Subgroup analyses of CEA and CAS showed that female gender and smoking status were significantly associated with recurrent stenosis after CEA but not after CAS. In contrast, hypertension was associated with restenosis after CAS but not after CEA. Patch endarterectomy (HR, 0.33; 95% CI, 0.22-0.50; I2, 0%) and symptomatic status at presentation in the CAS group (HR, 0.61; 95% CI, 0.41-0.90; I2, 0%) were associated with a decreased risk of restenosis. Antiplatelet use and coronary artery disease were not associated with restenosis risk. CONCLUSIONS: Diabetes, dyslipidemia, female gender, renal failure, hypertension, and smoking were associated with an increased risk of restenosis, and patch endarterectomy and symptomatic status at presentation were associated with a decreased risk of carotid restenosis. Both female gender and current smoking status were only associated with recurrent stenosis after CEA, and hypertension was only associated with restenosis after CAS.

Outcome Trends after US Military Concussive Traumatic Brain Injury.

Care for US military personnel with combat-related concussive traumatic brain injury (TBI) has substantially changed in recent years, yet trends in clinical outcomes remain largely unknown. Our prospective longitudinal studies of US military personnel with concussive TBI from 2008-2013 at Landstuhl Regional Medical Center in Germany and twp sites in Afghanistan provided an opportunity to assess for changes in outcomes over time and analyze correlates of overall disability. We enrolled 321 active-duty US military personnel who sustained concussive TBI in theater and 254 military controls. We prospectively assessed clinical outcomes 6-12 months later in 199 with concussive TBI and 148 controls. Global disability, neurobehavioral impairment, depression severity, and post-traumatic stress disorder (PTSD) severity were worse in concussive TBI groups in comparison with controls in all cohorts. Global disability primarily reflected a combination of work-related and nonwork-related disability. There was a modest but statistically significant trend toward less PTSD in later cohorts. Specifically, there was a decrease of 5.9 points of 136 possible on the Clinician Administered PTSD Scale (-4.3%) per year (95% confidence interval, 2.8-9.0 points, p = 0.0037 linear regression, p = 0.03 including covariates in generalized linear model). No other significant trends in outcomes were found. Global disability was more common in those with TBI, those evacuated from theater, and those with more severe depression and PTSD. Disability was not significantly related to neuropsychological performance, age, education, self-reported sleep deprivation, injury mechanism, or date of enrollment. Thus, across multiple cohorts of US military personnel with combat-related concussion, 6-12 month outcomes have improved only modestly and are often poor. Future focus on early depression and PTSD after concussive TBI appears warranted. Adverse outcomes are incompletely explained, however, and additional studies with prospective collection of data on acute injury severity and polytrauma, as well as reduced attrition before follow-up will be required to fully address the root causes of persistent disability after wartime injury.

Percutaneous transvenous embolization of a dural arteriovenous fistula through a mastoid emissary vein. Technical note.

Definitive endovascular treatment of dural arteriovenous fistulas (DAVFs) requires obliteration of the site of the fistula: either the diseased dural sinus or the pial vein. Access to this site is often limited by occlusion of the sinus proximal and distal to the segment containing the fistula. The authors describe a technique in which the mastoid emissary vein is used to gain access to a Borden-Shucart Type II DAVF in the transverse-sigmoid sinus. Recognition of this route of access, if present, may facilitate endovascular treatment of these lesions. Access to the transverse sinus via this approach can be straightforward and may be underused.

Effect of intraarterial verapamil on the diameter of vasospastic intracranial arteries in patients with cerebral vasospasm.

OBJECT: This study was conducted to determine whether there is a change in intracranial arterial diameters after verapamil infusion for vasospasm and, if it is present, to determine whether the change occurs in proximal, intermediate, or distal vessels. METHODS: The authors measured arterial diameters in all patients treated with intraarterial verapamil at their institutions between August 2003 and September 2004. In all, 18 treatments were examined in 15 patients. Measurements were made before and after verapamil infusion in a blinded fashion with the aid of a magnification loupe at nine predetermined arterial sites on each angiogram. Baseline arterial measurements were made on each patient's initial angiogram and on the angiogram demonstrating spasm prior to endovascular therapy as well in 14 of the patients. Charts were retrospectively reviewed to determine whether the patients benefited from intraarterial verapamil. From the time of the initial angiogram to the time of vasospasm, there was a 21.6% decrease (p = 0.092) in proximal artery diameter, a 47.1% decrease (p < 0.05) in intermediate artery diameter, and a 12.4% decrease (p < 0.05) in distal artery diameter. There were no significant changes in the diameters of proximal, intermediate, or distal vessels after verapamil infusion (mean dose 7.4 mg, range 2.5-10 mg). After infusion of intraarterial verapamil, the proximal vessels showed a 1.1% decrease in diameter, the intermediate vessels showed a 9.4% increase, and the distal vessels showed a 3.3% decrease. CONCLUSIONS: Administration of intraarterial verapamil does not cause a significant increase in the diameter of vasospastic vessels at the administered doses.

Pipeline Embolization Device for treatment of high cervical and skull base carotid artery dissections: clinical case series.

BACKGROUND: Most cervical dissections are treated with anticoagulation or antiplatelet agents with very good results; however, some patients may benefit from endovascular intervention. High cervical and skull base dissections are often more challenging to treat because of the distal location and tortuous anatomy. The Pipeline Embolization Device (PED) may be a reasonable treatment option for this indication. OBJECTIVES: To report a case series of patients treated with the PED for high cervical and skull base dissections, focusing on their presentation, indications for treatment, dissection revascularization success, and pseudoaneurysm obliteration evaluated by imaging, and to review available pertinent literature. METHODS: We retrospectively reviewed all cases of high cervical and skull base dissections treated with a PED at our institution. Patient clinical characteristics, presentation, procedural and follow-up imaging, and clinical course were analyzed to evaluate for procedure complications, dissection revascularization success, pseudoaneurysm obliteration, and clinical outcome. RESULTS: This is a retrospective case series including 11 patients with 13 carotid dissections treated in our center. There were nine traumatic and four spontaneous dissections. The most common presentation was cerebrovascular accident/transient ischemic attack (CVA/TIA; 5 patients) and headache/face pain (4 patients). Eleven dissections were associated with pseudoaneurysms. Three patients failed medical management with anticoagulation, although flow-limiting stenosis was the main indication for endovascular intervention. Up to three PEDs per vessel were deployed. Angioplasty was used in 10 cases. Complete revascularization (<10% residual stenosis) was achieved in 91% of vessels and 50% of pseudoaneurysms were completely or near completely obliterated immediately after PED(s) deployment. Proximal iatrogenic dissection was the only intraoperative complication. Follow-up imaging was available for nine treated vessels and demonstrated patent PEDs without significant in-stent stenosis up to 9 months after intervention. 75% of pseudoaneurysms were completely obliterated at follow-up. One PED partially collapsed but had no neurological consequences. There were no new CVA/TIAs. CONCLUSIONS: Our initial experience with treatment of high cervical and skull base dissections with the PED appears to show that this technique may be a safe and viable treatment option. However, long-term results are needed to fully evaluate the efficacy of such treatment.

Use of a side branch in a saphenous vein interposition graft for high-flow extracranial-intracranial bypass procedures. Technical note.

Saphenous vein (SV) interposition grafts are often used for high-flow extracranial-intracranial bypass procedures. During these procedures, it is essential to remove air and debris from the graft and to evaluate blood flow through the graft after it has been anastomosed to other cortical vessels. In this paper, the authors describe the preservation of a large side branch on the proximal end of the SV. This side branch can be used to flush out air and debris from the graft and to evaluate blood flow during revascularization.

Moyamoya disease in adults: the role of cerebral revascularization.

Moyamoya disease is a disorder characterized by bilateral progressive steno-occlusion of the terminal internal carotid arteries with associated development of a fragile network of basal collateral vessels. It most commonly presents in children, but is also frequently seen in adults, especially in the third or fourth decade of life. Adults afflicted with this disease have very different clinical characteristics as compared with children. For example, adults more commonly present with hemorrhage than cerebral ischemia, while children present with cerebral ischemia nearly 75% of the time and very rarely present with hemorrhage. This significantly impacts treatment considerations for the adult-onset moyamoya patient, as cerebral revascularization, though well accepted in the context of cerebral ischemia, is relatively controversial for the prevention of rehemorrhage. The purpose of this article is to review the pertinent general features of moyamoya disease, examine the clinical characteristics associated with the adult-onset form of this disease, and provide a detailed discussion regarding the indications, operative techniques, and outcomes of direct and indirect revascularization surgical procedures.

Spontaneous fusiform middle cerebral artery aneurysms: characteristics and a proposed mechanism of formation.

OBJECT: The goal of this study was to identify the origins of spontaneous fusiform middle cerebral artery (MCA) aneurysms. METHODS: One hundred two cases of spontaneous fusiform MCA aneurysms were reviewed, including 40 from the authors' institutions and 62 identified from the literature. The mean age at symptom onset was 38 years, and the male/female ratio was 1.4:1. At presentation, the MCA lumen was stenosed or occluded in 12 patients, focally dilated in 57, and appeared "serpentine" in 33. Most lesions originated from the M1 or M2 segments, and most (80%) presented with nonhemorrhagic symptoms or were discovered incidentally. The presenting clinical features correlated with morphological findings in the aneurysms, which could be observed to progress from a small focal dilation or vessel narrowing to a serpentine channel. Hemorrhage was the most common presentation in small lesions; the incidence of bleeding progressively diminished with larger lesions. Patients with stenoses or occluded vessels most often presented with ischemic symptoms, and occasionally with hemorrhage. Giant focal dilations or serpentine aneurysms were rarely associated with acute bleeding; clinical presentation was most often prompted by mass effect or thromboembolic stroke. CONCLUSIONS: Analysis of results after various treatments indicates that for symptomatic lesions, therapies that reverse intraaneurysmal blood flow and augment distal cerebral perfusion are associated with better outcomes than other strategies, including conservative management. Based on the spectrum of clinical, pathological, neuroimaging, and intraoperative findings, dissection is proposed as the underlying cause of these lesions.

Clinical outcomes and complications associated with pedicle screw fixation-augmented lumbar interbody fusion.

OBJECT: The authors conducted a prospective study to evaluate the clinical and radiological outcomes and complications associated with uni- and bilateral transforaminal lumbar interbody fusion (TLIF) performed using carbon fiber Brantigan I/F Cages and pedicle screw fixation. METHODS: Forty-two consecutive patients who had undergone uni- or bilateral TLIF between February 1999 and July 2000 were prospectively evaluated. Clinical outcome was graded using a modified Prolo Scale, the McGill Pain Index Scale, a follow-up questionnaire, and charts. An independent radiologist assessed radiological outcomes. All patients were followed for at least 1 year. Based on Prolo Scale scores, an excellent or good 1-year outcome was achieved in 73% of patients; 90% of patients responded that they would undergo the procedure again. At 1 year, radiographic fusion was demonstrated in 74% and was statistically related to clinical outcome (p < 0.05). There were no deaths or major hardware failures. Complications requiring repeated surgery included one case of cerebrospinal fluid (CSF) leakage and one case in which the hemovac drain was retained. There were four cases involving minor wound infections, eight involving CSF leaks, and none requiring repeated surgery. On routine follow-up radiography one pedicle screw was found to be broken; the patient remained asymptomatic and fusion occurred. CONCLUSIONS: Unilateral and bilateral TLIF involving placement of carbon fiber cages and pedicle screw fixation are effective treatment options in patients with indications for lumbar arthrodesis. The procedures result in acceptable rates of fusion and clinical success, and a minimal incidence of morbidity when performed by an experienced surgeon.

The freedom to heal: nonrigid immobilization by a halo orthosis.

Halo orthoses present a paradox. On the one hand, the nominally rigid immobilization they provide to the head aims to remove loads on the cervical spine following injury or surgery, and the devices are retightened routinely to maintain this. On the other hand, bone growth and remodeling are well known to require mechanical stressing. How are these competing needs balanced? To understand this trade-off in an effective, commercial halo orthosis, the authors quantified the response of a commercial halo orthosis to physiological loading levels, applied symmetrically about the sagittal plane. They showed for the first time that after a few cycles of loading analogous to a few steps taken by a patient, the support presented by a standard commercial halo orthosis becomes nonlinear. When analyzed through straightforward structural modeling, these data revealed that the nonlinearity permits mild head motion while severely restricting larger motion. These observations are useful because they open the possibility that halo orthosis installation could be optimized to transfer mild spinal loads that support healing while blocking pathological loads.