Optically-guided frameless linac-based radiosurgery for brain metastases: clinical experience.

The purpose of this study was to describe our clinical experience using optically-guided linear accelerator (linac)-based frameless stereotactic radiosurgery (SRS) for the treatment of brain metastases. Sixty-five patients (204 lesions) were treated between 2005 and 2008 with frameless SRS using an optically-guided bite-block system. Patients had a median of 2 lesions (range, 1-13). Prescription dose ranged from 14 to 22 Gy (median, 18 Gy) and was given in a single fraction. Clinical and radiographic evaluation occurred every 2-4 months following treatment. At a median follow-up of 6.2 months, actuarial survival at 12 months was 40% [95% confidence interval (CI), 28-52). Of 135 lesions that were evaluable for local control (LC), 119 lesions (88%) did not show evidence of progression. Actuarial 12 month LC was 76% (95% CI, 66-86). Tumors 2 cm. Adverse events occurred in three patients (5%). Optically-guided linac-based frameless SRS can produce clinical outcomes that compare favorably to frame-based techniques. As this technique is convenient to use and allows for the uncomplicated delivery of hypofractionated radiotherapy, frameless SRS will likely have an increasingly important role in the management of brain metastases.

The risk of growing skull fractures in craniofacial patients.

BACKGROUND/AIMS: Growing skull fractures (GSFs) are unusual sequelae of head injury in young children which have also been reported to occur after craniofacial procedures complicated by inadvertent durotomy. We reviewed the craniofacial experience in a single institution, detailing 180 cases of craniofacial surgery and suspected dural tears and their relationship to the subsequent development of GSFs. This experience was then compared to that of the pertinent published literature. METHODS: A retrospective review of the senior authors' craniofacial surgical experience from 2000 to 2007 was performed. This was compared to an English-language literature review of GSFs after craniofacial surgery. RESULTS: In our institution, 180 cases of craniofacial surgery (83 open, 97 endoscopic) were performed, with an average follow-up of 23.5 months. Twenty-five patients (15 open, 10 endoscopic surgeries) had operative dural compromise. One of these patients developed a persistent pseudomeningocele requiring reoperation. Twelve cases of GSF after craniofacial surgery were identified in a review of the English-language literature, of which 7 (58%) had coronal suture fusion. CONCLUSIONS: While durotomy may occur during craniofacial surgery, the subsequent development of a GSF appears to be an unlikely event with an aggressive intraoperative approach of identification and repair. Coronal craniosynostosis may confer an increased risk for this complication.

Endovascular treatment of extensive cerebral sinus thrombosis.

Cerebral venous and sinus thrombosis is an uncommon but potentially lethal event. Although thrombosis accounts for only 1% of all strokes, if it is left untreated patients suffer from continuing headaches, vague neurological complaints, and may even progress to coma and death. New endovascular techniques and technology allow the possibility of more aggressive thrombolysis and thrombectomy in the setting of acute thrombosis. The authors present a case of recanalization of an extensive cerebral thrombosis using a new endovascular retrieval device.

Relaxation of forces needed to distract cervical vertebrae after discectomy: a biomechanical study.

STUDY DESIGN: In vitro and in vivo biomechanical stress measurements are made of the intervertebral disc segment distraction force during anterior cervical discectomy. OBJECTIVE: The purpose of this study is to determine the short-term force relaxation of the native intervertebral disc segment and to determine the short-term force relaxation of the segment after removal of the intervertebral disc, as is commonly performed in anterior cervical discectomy with fusion and arthroplasty. SUMMARY OF BACKGROUND DATA: No published data examine the issue of intraoperative distraction force of the cervical intervertebral disc segment. This is a novel research in this area. METHODS: In vitro and in vivo studies under institutional review board approval were performed to determine the mechanical behavior of the normal and diseased cervical functional spinal unit. Seven in vitro and 11 in vivo spines were studied. Strain measurements between distracting Caspar-type pins were made before, at various points during, and after discectomy to assess how removal of the disc and other spinal components affects the force-displacement behavior of the spinal unit. RESULTS: The in vitro data show progressive reduction in force needed for distraction after discectomy and uncovertebral joint resection. Greatest reduction is noted after discectomy. The in vivo data indicate that, on average, the cervical functional spinal unit requires 20 N less force to achieve the same degree of distraction after removal of the intervertebral disc. CONCLUSIONS: A sharp reduction in the strain across the intervertebral space occurs after distraction. The removal of the cervical intervertebral disc significantly reduces the viscoelastic response of the cervical motion segment. The long-term force used to stabilize intervertebral grafts or implants is less than what is achieved at the time of distraction. The exact magnitude of the resultant force on graft or device at a given distraction force is unknown and would depend also upon fit.

Stabilization of the atlantoaxial complex via C-1 lateral mass and C-2 pedicle screw fixation in a multicenter clinical experience in 102 patients: modification of the Harms and Goel techniques.

OBJECT: Stabilization of the atlantoaxial complex has proven to be very challenging. Because of the high mobility of the C1-2 motion segment, fusion rates at this level have been substantially lower than those at the subaxial spine. The set of potential surgical interventions is limited by the anatomy of this region. In 2001 Jürgen Harms described a novel technique for individual fixation of the C-1 lateral mass and the C-2 pedicle by using polyaxial screws and rods. This method has been shown to confer excellent stability in biomechanical studies. Cadaveric and radiographic analyses have indicated that it is safe with respect to osseous and vascular anatomy. Clinical outcome studies and fusion rates have been limited to small case series thus far. The authors reviewed the multicenter experience with 102 patients undergoing C1-2 fusion via the polyaxial screw/rod technique. They also describe a modification to the Harms technique. METHODS: One hundred two patients (60 female and 42 male) with an average age of 62 years were included in this analysis. The average follow-up was 16.4 months. Indications for surgery were instability at the C1-2 level, and a chronic Type II odontoid fracture was the most frequent underlying cause. All patients had evidence of instability on flexion and extension studies. All underwent posterior C-1 lateral mass to C-2 pedicle or pars screw fixation, according to the method of Harms. Thirty-nine patients also underwent distraction and placement of an allograft spacer into the C1-2 joint, the authors' modification of the Harms technique. None of the patients had supplemental sublaminar wiring. RESULTS: All but 2 patients with at least a 12-month follow-up had radiographic evidence of fusion or lack of motion on flexion and extension films. All patients with an allograft spacer demonstrated bridging bone across the joint space on plain x-ray films and computed tomography. The C-2 root was sacrificed bilaterally in all patients. A postoperative wound infection developed in 4 patients and was treated conservatively with antibiotics and local wound care. One patient required surgical debridement of the wound. No patient suffered a neurological injury. Unfavorable anatomy precluded the use of C-2 pedicle screws in 23 patients, and thus, they underwent placement of pars screws instead. CONCLUSIONS: Fusion of C1-2 according to the Harms technique is a safe and effective treatment modality. It is suitable for a wide variety of fracture patterns, congenital abnormalities, or other causes of atlantoaxial instability. Modification of the Harms technique with distraction and placement of an allograft spacer in the joint space may restore C1-2 height and enhance radiographic detection of fusion by demonstrating a graft-bone interface on plain x-ray films, which is easier to visualize than the C1-2 joint.

Over-the-catheter retrieval of a retained microcatheter following Onyx embolization: a technical report.

BACKGROUND: Brain arteriovenous malformations are vascular lesions that are increasingly being treated with endovascular embolization. A potential complication with endovascular embolization is microcatheter entrapment within the embolic material. In the present report, a novel technique for the retrieval of microcatheters retained during Onyx embolization of intracranial lesions is described. CLINICAL PRESENTATION: Two patients (one boy and one girl, aged 13 and 15 years, respectively) with arteriovenous malformations (one unruptured, one ruptured; Spetzler-Martin grades 4 and 3) presented for embolization. INTERVENTION: During Onyx 18 embolization of the arteriovenous malformations, Echelon-10 microcatheters became entrapped into the arterial feeders by casts of the Onyx. Initial attempts to remove the microcatheters by traction were unsuccessful. The hubs of the microcatheters were transected and Concentric Medical Outreach distal access catheters were then advanced over the microcatheters and positioned at the proximal aspects of the microcatheter-Onyx plugs. Using the Outreach catheters for countertraction, the Echelon-10 microcatheters were then successfully released from the Onyx plugs under fluoroscopic visualization without significant distortion of the arteries. There were no complications related to the microcatheter extractions. CONCLUSIONS: A novel technique, which may be useful in the removal of retained microcatheters during Onyx embolization of Brain arteriovenous malformations, is presented.

Expandable titanium cages for thoracolumbar vertebral body replacement: initial clinical experience and review of the literature.

Reconstruction of the anterior and middle column after vertebrectomy is essential for restoring stability. Use of expandable implants is supported by an emerging body of literature. Newer expandable cages have some advantages over traditional mesh implants, structural allograft, and polyetheretherketone or carbon fiber cages. To determine the utility of an expandable titanium cage in spine reconstruction, we conducted a retrospective cohort study of patients who had undergone this reconstruction after single or multilevel thoracic and/or lumbar vertebrectomy. Here we report on our experience using expandable cages at 2 large academic medical centers. Outcome was based on both clinical and radiographic measures with cross-sectional analysis. Thirty-five patients were identified. Of these, 20 had undergone surgery for neoplasm, 8 for trauma, and 7 for infection. Mean follow-up was 31 months (range, 12 to 50 months). Early postoperative kyphosis correction, restoration of sagittal alignment at 12 months, and reduction in visual analog scale pain score were significant. There was no difference in Oswestry Disability Index or height restoration. Expandable intervertebral body strut grafts appear to be a safe and effective option in spine reconstruction after a vertebrectomy and should be considered a treatment option.

Balloon-assisted Onyx embolization of cerebral single-channel pial arteriovenous fistulas.

OBJECT: Pial arteriovenous fistulas (AVFs) of the brain are rare vascular malformations associated with significant risks of hemorrhage and neurological deficit. Depending on their location and high-flow dynamics, these lesions can present treatment challenges for both endovascular and open cerebrovascular surgeons. The authors describe a novel endovascular treatment strategy that was used successfully to treat 2 pediatric patients with a pial AVF, and they discuss the technical nuances specific to their treatment strategy. METHODS: A single-channel high-flow pial AVF was diagnosed in 2 male patients (6 and 17 years of age). Both patients were treated with endovascular flow arrest using a highly conformable balloon followed by Onyx infusion for definitive closure of the fistula. RESULTS: Neither patient suffered a complication as a result of the procedure. At the 6-month follow-up in both cases, the simple discontinuation of blood flow had resulted in durable obliteration of the fistula and stable or improved neurological function. CONCLUSIONS: Onyx can be delivered successfully into high-flow lesions after flow arrest to allow a minimally invasive and durable treatment for pial AVFs.

Transarterial Onyx embolization of sacral chordoma: case report and review of the literature.

AIM: To report a successful transarterial Onyx embolization of a highly vascularized sacral chordoma. CASE PRESENTATION: A 74-year-old patient presented with progressive lower back pain and anorectal and urogenital dysfunction complicated by excessive intraoperative blood loss requiring emergent endovascular intervention. INTERVENTION: Emergent pelvic angiography demonstrated a highly vascularized sacral chordoma. Transarterial embolization with Onyx was performed successfully via a single arterial pedicle, the median sacral artery. Surgical extirpation was achieved with the expected amount of intraoperative blood loss without further complications. CONCLUSION: Preoperative transarterial Onyx embolization can be performed safely and effectively to assist in the surgical resection of sacral chordomas.

Intracranial venous sinus stenting for benign intracranial hypertension: clinical indications, technique, and preliminary results.

OBJECTIVE: The cause of pseudotumor cerebri, or benign intracranial hypertension (BIH), is controversial. We report our results from 18 cases of venous sinus stenting (VSS), the largest series in the literature, with specific focus on the rate of technical success, amelioration of the subjective symptom of headache, attendant complications, and radiographic patency on follow-up. METHODS: Review of our prospectively maintained database identified 18 patients who had undergone 19 VSS procedures for the placement of 30 stents in the past 2.5 years. Indications for treatment included a clinical diagnosis of BIH with venographic demonstration of stenosis. RESULTS: VSS was technically successful in all patients (100%). No patient suffered a permanent complication. Three patients were lost to follow-up. The remaining 15 patients were followed clinically and asked to rate their headache severity on a scale of 1 to 10 both before and after VSS. Overall, 12 patients (80%) qualified their headaches as better after VSS, two stated that they were the same, and one patient said that they were worse. Of 14 patients who underwent follow-up angiography, all demonstrated normal patency of the stented segments. In one of these patients, stenosis was detected on follow-up in the unstented segment of the sigmoid sinus and jugular bulb. CONCLUSIONS: VSS is highly effective (80%) in ameliorating headache associated with BIH. The procedure is associated with a high rate of technical success (100%), a low rate of permanent complications (0), and a high rate of stent patency on follow-up angiography (100%).

Cranial dural arteriovenous fistula: transarterial Onyx embolization experience and technical nuances.

INTRODUCTION: Traditional endovascular treatment of cranial dural arteriovenous fistulas (DAVFs) consists of a transarterial approach with n-butylcyanoacrylate (nBCA) or a transvenous approach with coil embolization. The advent of Onyx in the endovascular arsenal potentially offers a high probability of obliteration of these vascular lesions through a purely transarterial route. METHODS: A retrospective review of the Barrow Neurological Institute endovascular database between October 2005 and November 2009 highlighted 50 patients with 63 cranial DAVFs that were treated with transarterial Onyx, with and without adjuvant embolysates, for a total of 76 embolization procedures. Hospital records, cerebral angiography and other diagnostic imaging and clinical visits were reviewed. RESULTS: At a median follow-up of 5 months (range 0-25 months), complete angiographic cure was obtained in 41 patients with 50 (79%) DAVFs after transarterial embolization using Onyx combined with other embolysates. When Onyx was used as the sole embolic agent, 32 of 37 DAVFs (87%) in 29 (of 33) patients achieved angiographic cure. Subgroup analysis showed that by using the middle meningeal artery (MMA) as a conduit for primary Onyx embolization, angiographic cures were achieved in 27 of the 37 DAVFs (73%). Periprocedural complications occurred in six (7.9%) sessions in one patients (8%). Only one patient had a permanent complication (2%) with unimproved cranial nerve palsies. CONCLUSION: Transarterial Onyx embolization of cranial DAVFs, particularly using the MMA as a conduit, is a safe and effective curative therapy.

Percutaneous transluminal angioplasty in a patient with vasospasm secondary to coccidioidal meningitis: case report and review of the literature.

INTRODUCTION: Coccidioidomycosis is secondary to infection with fungal species Coccidioides immitis or Coccidioides posadasii. One consequence of extrapulmonary coccidioidomycosis dissemination is meningitis, which is associated with high rates of morbidity and mortality if left untreated. Intracranial vasospasm, although rarely described, can occur and may be a result of vasculitic or subacute fibrotic changes. We describe a case of successful percutaneous transluminal angioplasty (PTA) in a patient with severe vasospasm related to coccidioidal meningitis. This is the first report of this endovascular treatment used to treat coccidioidal vasospasm. CLINICAL PRESENTATION: A patient with a history of pulmonary coccidioidomycosis presented with acute confusion, blurry vision and headache. Serology confirmed basilar meningitis and magnetic resonance angiography demonstrated severe symptomatic vasospasm. INTERVENTION: Emergent cerebral angiography confirmed severe vasospasm in the right middle cerebral artery and moderate vasospasm in the left middle cerebral artery. Successful PTA was performed under general anesthesia. The patient demonstrated postprocedural angiographic and clinical improvement. CONCLUSION: We report the first case of successful PTA performed to treat vasospasm related to coccidioidal meningitis. When vasospasm is clinically symptomatic, PTA is a safe and feasible procedure.

Transcirculation endovascular treatment of complex cerebral aneurysms: technical considerations and preliminary results.

BACKGROUND: Unfavorable anatomy can preclude embolization of intracranial aneurysms. Transcirculation techniques, in which a catheter is navigated from one side of the brain to the other or from the anterior to the posterior circulation, are alternative pathways for primary or balloon- or stent-assisted coiling. OBJECTIVE: We report the largest experience in coil embolization of aneurysms using transcirculation techniques. METHODS: We reviewed our endovascular database from 2006 to 2009 and identified 18 patients who had aneurysms treated with transcirculation techniques. RESULTS: Eight patients had anterior and 10 had posterior circulation aneurysms. Overall, 8 patients were treated with stent-assisted coiling and 9 with balloon-assisted coiling, including 1 patient treated with a "kissing balloon" technique. Of the 9 patients treated with balloon-assistance, 1 also was stented at the conclusion of aneurysm coiling. One patient with a left fourth vertebral artery (V4) aneurysm was treated with coiling alone via a bilateral vertebral artery (VA) approach. In 14 patients, the anterior communicating and posterior communicating arteries were used as conduits. In 4 patients, both VAs were traversed to treat 2 V4 aneurysms and 2 posterior inferior cerebellar artery aneurysms. One patient died as a result of treatment and was the only permanent complication (5.6%). Complete or near-complete (>95%) embolization was achieved in all patients. CONCLUSION: Transcirculation techniques are effective pathways for embolization of complex aneurysms. Although technically challenging, these techniques are associated with an acceptably low rate of complications when compared to the natural history of the treated lesion.

Posterior approach for thoracolumbar corpectomies with expandable cage placement and circumferential arthrodesis: a multicenter case series of 67 patients.

OBJECT: The purpose of this multicenter trial was to investigate the outcome and durability of a single-stage thoracolumbar corpectomy using expandable cages via a posterior approach. METHODS: The authors conducted a retrospective chart review of 67 consecutive patients who underwent single-stage thoracolumbar corpectomies with circumferential reconstruction for pathological, traumatic, and osteomyelitic pathologies. Circumferential reconstruction was accomplished using expandable cages along with posterior instrumentation and fusion. Correction of the sagittal deformity, the American Spinal Injury Association score, and complications were recorded. RESULTS: Single-stage thoracolumbar corpectomies resulted in an average sagittal deformity correction of 6.2° at a mean follow-period of 20.5 months. At the last follow-up, a fusion rate of 68% was observed for traumatic and osteomyelitic fractures. Approximately one-half of the patients remained neurologically stable. Improvement in neurological function occurred in 23 patients (38%), whereas 7 patients (11%) suffered from a decrease in lower-extremity motor function. The deterioration in neurological function was due to progression of metastatic disease in 5 patients. Five constructs (7%) failed-3 of which had been placed for traumatic fractures, 1 for a pathological fracture, and 1 for an osteomyelitic fracture. Other complications included epidural hematomas in 3 patients and pleural effusions in 2. CONCLUSIONS: Single-stage posterior corpectomy and circumferential reconstruction were performed at multiple centers with a consistent outcome over a wide range of pathologies. Correction of the sagittal deformity was sustained, and the neurological outcome was good in the majority of patients; however, 18% of acute traumatic fractures required revision of the construct.

Acute transient cortical blindness due to seizure following cerebral angiography.

OBJECTIVE: Transient cortical blindness (TCB) is reported as a rare complication of coronary and cerebral angiography. Angiography of the vertebral arteries carries the highest incidence of causing TCB. The etiology of this phenomenon is unknown. CLINICAL PRESENTATION: A 42-year-old woman underwent treatment for an enlarging pseudoaneurysm of her vertebral artery. The patient had a brief complex seizure during angiography. Following the procedure, she experienced TCB. During this time, an electroencephalogram (EEG) showed seizure activity. This case represents the first recorded instance of abnormal EEG during angiography-associated TCB. INTERVENTION: The patient was immediately given intravenous lorazepam and phenytoin sodium. Her EEG returned to normal in the ensuing hours and subsequently her vision returned to normal. CONCLUSION: We present the first reported case of abnormal EEG activity during angiography-associated TCB. We hypothesize that seizure activity is a possible underlying cause of angiography-induced TCB.

Mortality resulting from head injury in professional boxing: case report.

BACKGROUND: The majority of boxing-related fatalities result from traumatic brain injury. Biomechanical forces in boxing result in rotational acceleration with resultant subdural hematoma and diffuse axonal injury. OBJECTIVE: Given the inherent risk and the ongoing criticism boxing has received, we evaluated mortalities associated with professional boxing. METHODS: We used the Velazquez Fatality Collection of boxing injuries and supplementary sources to analyze mortality from 1950 to 2007. Variables evaluated included age at time of death, association with knockout or other outcome of match, rounds fought, weight class, location of fight, and location of preterminal event. RESULTS: There were 339 mortalities between 1950 and 2007 (mean age, 24 +/- 3.8 years); 64% were associated with knockout and 15% with technical knockout. A higher percentage occurred in the lower weight classes. The preterminal event occurred in the ring (61%), in the locker room (17%), and outside the arena (22%). We evaluated for significant changes after 1983 when championship bouts were reduced from 15 to 12 rounds. CONCLUSION: There was a significant decline in mortality after 1983. We found no significant variables to support that this decline is related to a reduction in rounds. Rather, we hypothesize the decline to be the result of a reduction in exposure to repetitive head trauma (shorter careers and fewer fights), along with increased medical oversight and stricter safety regulations. Increased efforts should be made to improve medical supervision of boxers. Mandatory central nervous system imaging after a knockout could lead to a significant reduction in associated mortality.

Mortality resulting from head injury in professional boxing.

BACKGROUND: The majority of boxing-related fatalities result from traumatic brain injury. Biomechanical forces in boxing result in rotational acceleration with resultant subdural hematoma and diffuse axonal injury. OBJECTIVE: Given the inherent risk and the ongoing criticism boxing has received, we evaluated mortalities associated with professional boxing. METHODS: We used the Velaquez Fatality Collection of boxing injuries and supplementary sources to analyze mortality from 1950 to 2007. Variables evaluated included age at time of death, association with knockout or other outcome of match, rounds fought, weight class, location of fight, and location of pretermial event. RESULTS: There were 339 mortalities between 1950 and 2007 (mean age, 24 ± 3.8 years); 64% were associated with knockout and 15% with technical knockout. A higher percentage occurred in the lower weight classes. The preterminal event occurred in the ring (61%), in the locker room (17%), and outside the arena (22%), We evaluated for significant changes after 1983 when championship bouts were reduced from 15 to 12 rounds. CONCLUSION: There was a significant decline in mortality after 1983. We found no significant variables to support that this decline is related to a reduction in rounds. Rather, we hypothesize the decline to be the result of a reduction in exposure to repetitive head trauma (shorter careers and fewer fights), along with increased medical oversight and stricter safety regulations. Increased efforts should be made to improve medical supervisions of boxers. Mandatory central nervous system imaging after a knockout could lead to a significant reduction in associated mortality.

En bloc sacrectomy and reconstruction: technique modification for pelvic fixation.

BACKGROUND: When the management of sacral tumors requires partial or complete sacrectomy, the spinopelvic apparatus must be reconstructed. This is a challenging and infrequently performed operation, and as such, many spine surgeons are unfamiliar with techniques available to carry out these procedures. CASE DESCRIPTION: A 34-year-old man presented with severe low back pain, mild left ankle dorsiflexion weakness, and left S1 paresthesias. Imaging revealed a large sacral mass extending into the L5/S1 and S1/S2 neural foramina as well as the presacral visceral and vascular structures. Needle biopsy of this mass demonstrated a low-grade chondrosarcoma. A 2-stage anterior/posterior en bloc sacrectomy with a novel modification of the Galveston L-rod pelvic ring reconstruction was carried out. Our modification takes advantage of new materials and implant technology to offer another alternative in reconstruction of the spinopelvic junction. CONCLUSION: Understanding the anatomy and biomechanics of the spinopelvic apparatus and the lumbosacral junction, as well as having a familiarity with the various techniques available for carrying out sacrectomy and pelvic ring reconstruction, will enable the spine surgeon to effectively manage sacral tumors.