Rate of Return to Military Active Duty After Single and 2-Level Anterior Cervical Discectomy and Fusion: A 4-Year Retrospective Review.

BACKGROUND: Over the years of rigorous of military service, military personnel may experience cervical spondylosis and radiculopathy. Given the frequency of this occurrence, the capacity to return to unrestricted full duty in the military after anterior cervical discectomy and fusion (ACDF) is worthy of analysis. OBJECTIVE: To identify the rate of return to full, unrestricted active duty after single and 2-level anterior cervical discectomy, and fusion surgery in military personnel. METHODS: A retrospective chart review was performed at a tertiary care military treatment facility for all active duty personnel who underwent a single or 2-level ACDF over a 4-yr period. Patient and procedural data were collected to include single or 2-level fusion, indication for surgery, fusion level, tobacco use, age, and military rank. Fischer's Exact and Wilcoxon Rank Sum tests were used to identify statistically significant differences in the rate of return to active duty. RESULTS: A total of 132 anterior cervical discectomy and fusions were analyzed. One hundred sixteen patients (88%) were able to return to unrestricted full active duty, while the remaining 16 required separation from the military for continued pain or disability. The return to active duty rate was significantly higher in service members with a rank of E7 or above (99%) than those E6 and below (73%). There was a strong association between the presence of a pseudoarthrosis and the capacity to return to full duty (P = .013). CONCLUSION: Both single and 2-level ACDFs have high overall success with an 88% rate of return to full duty.

Hypoglossal schwannomas: A systematic review of the literature.

BACKGROUND: Schwannomas of the hypoglossal nerve are rare and account for a very small percentage of non-vestibular schwannomas. OBJECTIVES: In this systematic review of the literature, we examined the epidemiology, symptomatology, management, and outcomes of patients with hypoglossal schwannomas. METHODS: The electronic database Pubmed was searched for all reports of hypoglossal schwannomas with descriptions of symptoms, management, and outcome characteristics. Data was extracted from each study and compiled in a spreadsheet. Continuous variables were reported as means and medians. Categorical variables were reported as proportions. Additional analysis was not done due to inconsistent reporting of outcomes and small sample sizes. RESULTS: A total of 59 studies (94 total individual cases) were included. 64% of patients were female with mean age of 44.6 years. The majority were intracranial/extracranial (50%). The most common symptoms were tongue deviation or speech disturbance (38%) and headaches (33%). Hypoglossal nerve dysfunction was present in 80% of patients. Surgical excision was performed in 93%, with a 15% complication rate. Evidence of residual mass after surgery was noted in 29%. Permanent hypoglossal nerve deficits occurred in 67%. Recurrence of tumor burden was reported in 6 studies, with median time to recurrence of 16.5 months. CONCLUSION: Current evidence suggests overall favorable outcomes with surgical resection of hypoglossal schwannomas, with a large percentage of patients experiencing mild and usually well-tolerated neurologic deficit. Limitations of this study include the use of retrospective data taken from case reports/series with highly selected patients, selective reporting, and absence of control groups.

Successful Novel Treatment of a Paraspinal Primitive Neuroectodermal Tumor with Predominantly Glial Differentiation: A 3-Year Follow-Up After Surgery, Intensity-Modulated Radiation Therapy and Oral Temozolomide.

BACKGROUND: Paraspinal masses are a relatively uncommon but diverse group of lesions that can be neoplastic or non-neoplastic. Peripheral primitive neuroectodermal tumors of the lumbar paraspinal region with diffuse and strong glial differentiation have never been reported before. CASE DESCRIPTION: We report a primary paraspinal primitive neuroectodermal tumor with overwhelming glial differentiation in a 23-year-old female patient who presented with intractable right lower extremity pain. The patient underwent a 2-staged operation with gross total resection of the mass followed by intensity-modulated radiation therapy and oral temozolomide, a regimen employed for high-grade intracranial gliomas. Serial imaging revealed no evidence of recurrence after 3 years. CONCLUSIONS: Although these lesions appear to be exceptionally rare, an approach similar to that of intracranial high-grade glial tumors was effective in our experience. Our patient had no evidence of recurrence at 3-year follow-up.

Dermoid cysts of the conus medullaris: Clinical review, case series and management strategies.

BACKGROUND: The management of dermoid cysts can be tedious as they have a tendency to recur, and respond poorly to chemotherapy and radiation. Management is especially difficult for tumors involving highly eloquent areas such as the conus medullaris. OBJECTIVE: We aim to provide a summary of the pathology, clinical presentation, and operative management strategies of dermoid cysts involving the conus medullaris. METHODS: Two clinical cases of dermoid cysts of the conus are presented, as well as a commented surgical video. RESULTS: A 33 year-old man with a history of cystic conus medullaris tumor presented with progressive low back pain and loss of bowel and bladder function. His magnetic resonance imaging (MRI) scan showed recurrence of his tumor with tethering of the spinal cord. He was taken for a midline myelotomy that drained yellowish keratinous fluid and decompressed the cyst. No aggressive attempt at complete resection of the cyst wall was undertaken. He made a complete recovery after surgery. A 25 year-old woman with a history of dermoid cyst of the conus that was previously treated surgically, presented with lower extremity weakness and debilitating pain. Her MRI showed significant recurrence of the cystic lesion. She was taken for a midline myelotomy and improved after surgery with complete resolution of her symptoms. CONCLUSION: Dermoid cysts of the conus medullaris are challenging to treat. Surgical control and restraint are key, especially when patients are young and could potentially fully recover and remain in remission for a period of years.

Hypoglossal Schwannoma of Neck: Case Report and Review of Literature.

BACKGROUND: Schwannomas are benign, slow-growing neoplasms of the myelin-producing Schwann cells of peripheral nervous system that most commonly affect sensory nerves. Hypoglossal schwannomas, tumors of purely motor nerves, comprise <5% of all head and neck schwannomas. Since the first description of a hypoglossal schwannoma in 1933, there have been few case reports of extracranial origins. The most common location of an extracranial hypoglossal schwannoma is in the parapharyngeal space and can mimic paragangliomas. We describe the case of a woman presenting with an enlarging neck mass originally thought to be a paraganglioma but ultimately discovered to be a hypoglossal schwannoma at surgery. CASE DESCRIPTION: A 63-year-old woman had a well-circumscribed, mobile, nontender, 3-cm firm mass at the mandibular angle. On computed tomography, the mass was at the level of the carotid bifurcation, splaying the branching vessels. It was further evaluated with magnetic resonance imaging, which revealed a homogeneous, T2-hyperintense, T1-isointense mass with homogeneous contrast enhancement and scant flow voids. Biopsy revealed a spindle cell mass with positive S-100 staining. She underwent resection with the mass originating from the hypoglossal nerve. CONCLUSIONS: Hypoglossal schwannomas are rare lesions with a variable location along the course of the nerve. An extracranial lesion was described here, which was initially mistaken for a paraganglioma. Surgical resection is the consensus recommendation and is often well tolerated with low risk of long-term recurrence.

Spinal Cord Compression Secondary to Epidural Fibrosis Associated with Percutaneously Placed Spinal Cord Stimulation Electrodes: Case Report and Review of the Literature.

Spinal cord stimulation is a safe method for treating chronic pain syndromes. Spinal cord stimulators can be placed either surgically by creating a laminectomy defect for paddle leads or percutaneously by inserting electrodes. They are usually not associated with major complications. There have been several reports of epidural fibrosis formation after paddle lead placement but only 1 case of excessive fibrosis following percutaneous lead placement. We describe the unique case of excessive cervical fibrosis formation with creation of tolerance phenomenon, clinically significant stenosis, cord compression, and myelopathy after percutaneous lead placement, which improved after surgical removal of the implant. We also reviewed the PubMed and Medline databases for all cases of significant epidural fibrosis related to spinal cord stimulator lead placement, including both surgically implanted paddles and percutaneously implanted leads. This is an uncommon complication after placement of spinal cord stimulators, but it can carry a clinically significant impact and be the source of severe morbidity. It should especially be suspected if the successful placement of the device is followed by development of a "tolerance" phenomenon, with progressive loss of satisfactory pain control and development of new myelopathic symptoms.

Epidural spinal cavernous hemangioma and hybrid vascular subtype.

AIM: To demonstrate less common pathologies of purely epidural spinal tumors that should be considered when noted on MRI prior to surgery. To expand the differential diagnosis of purely epidural spinal tumors and comment on their surgical implications. MATERIAL AND METHODS: We report on two patients from our institution with rare pathology. We also utilized PubMed to concisely review the literature concerning purely epidural vascular lesions akin to the cavernous hemangioma. RESULTS: We describe common clinical presentations, radiographic findings, histopathologic characteristics and treatment algorithms relevant to the rare pure spinal epidural cavernous hemangioma and a newly described compound hemangioma subtype. CONCLUSION: Epidural spinal tumors are relatively common entities, though lesions isolated to the epidural space without origination in the vertebral body or as part of neurologic presentation of metastatic disease, are much less common. Less common pathologies may be missed in the initial differential diagnosis with treatment implications at surgery.

AlloDerm for duraplasty in Chiari malformation: superior outcomes.

BACKGROUND: Autologous pericranium, fascia lata (either as autograft or allograft), bovine pericardium (DuraGuard), fetal bovine tissue (Durepair), processed collagen matrix (DuraGen), and synthetic fabrics (e.g., synthetic Goretex graft) have all been used for duraplasty in Chiari decompression surgery, and no consensus exists as to the optimal material. We reviewed our experience to compare the incidence of graft-related complications associated with using acellular human dermis allograft (AlloDerm) with those of DuraGuard, DuraGen, and Durepair. METHODS: In a retrospective cohort chart review, our cohort included 119 patients who underwent 128 Chiari decompression procedures by a single surgeon from January 1, 1997, through July 31, 2012. Age, sex, smoking status, weight, and the type of dural graft used were analyzed with univariate statistical tests. Dural grafts were selected based on the commercial products available at the time of surgery during this 15-year period. RESULTS: The reoperation rate for cerebrospinal fluid leak causing pseudomeningocele was 2.2 % (1/46 cases) with the AlloDerm graft and 17.1 % (14/82 cases) with other materials (p = 0.01). Each of the non-AlloDerm grafts had a higher reoperation rate than AlloDerm when analyzed separately. Not using AlloDerm was the only statistically significant factor for the need for reoperation (p = 0.01). CONCLUSIONS: The use of the AlloDerm dural graft for duraplasty in Chiari decompressions resulted in a significantly lower pseudomeningocele formation than the use of any other type of dural graft. There was no association between patient age, sex, extra weight, or smoking status and the need for reoperation.

Hemorrhagic intramedullary hemangioblastoma of the cervical spinal cord presenting with acute-onset quadriparesis: case report and review of the literature.

CONTEXT: Hemangioblastomas of the spinal cord are uncommon vascular tumors. Patients commonly present with subtle neurologic findings that are thought to represent growth of the lesion over time. Hemorrhage of an intramedullary hemangioblastoma presenting as acute neurologic deficit is an extremely rare occurrence. Although the cervical spine is the most common location for hemangioblastoma of the spinal cord, there have been no previously published cases in the literature of intramedullary hemorrhage from such a lesion. FINDINGS: A 22-year-old woman with a previously undiagnosed spinal cord hemangioblastoma presented with sudden-onset dense quadriparesis due to intramedullary hemorrhage in the cervical spinal cord. The patient did not have any clinical findings of von-Hippel Lindau disease. Laminoplasty from C5 to T2 and posterior midline myelotomy for resection of the intramedullary tumor with hematoma evacuation were completed without complication. CONCLUSION: Intramedullary hemangioblastoma of the spinal cord is uncommon, and hemorrhage from a cervical spinal cord lesion has not previously been reported. Symptoms from these usually indolent lesions are commonly associated with tumor growth, edema, or associated syrinx, whereas devastating acute neurologic deficit from hemorrhage is exceedingly rare. Microsurgical resection should be done in cases of symptomatic lesions and considered in isolated symptomatic lesions without the known diagnosis of von Hippel-Lindau disease.

Rate of return to military active duty after single level lumbar interbody fusion: a 5-year retrospective review.

BACKGROUND: Lumbar interbody fusion has been extensively studied in the civilian population; however, data regarding its efficacy in the military are lacking. OBJECTIVE: To identify the rate of return to unrestricted active military duty after single-level lumbar interbody fusion surgery. METHODS: The surgical database at a single tertiary care military treatment facility was queried for active-duty patients who underwent a single-level lumbar interbody fusion over a 5-year period. A retrospective chart review was performed with backward stepwise logistic regression analysis, and Fisher exact and Wilcoxon rank sum tests were used for statistical analysis. RESULTS: A total of 102 patients met the inclusion criteria. Mean age at surgery was 34.0 years (range, 19-51 years). Most surgeries (59%) were performed for discogenic pain secondary to degenerative disc disease; the remaining patients underwent surgery for spondylolisthesis (39%) or spinal stenosis (2%). Thirty-nine patients (38%) were treated via an anterior approach (anterior lumbar interbody fusion), whereas 63 patients (62%) underwent fusion via a posterior approach (transforaminal or posterior lumbar interbody fusion). Fifty-six patients (55%) were able to return to unrestricted full active duty, and the remaining 46 patients (45%) were separated from the military. The return to active duty rate was significantly higher in older patients and those ranking E7 (Chief Petty Officer) and above (84.8%). CONCLUSION: Fifty-five percent of the service members who underwent a single-level lumbar interbody fusion returned to unrestricted full duty. Older age and higher rank were statistically significant positive predictors of a successful return to active duty.

Progressive vertebral body osteolysis after cervical disc arthroplasty.

STUDY DESIGN: Case report. OBJECTIVE: To review the management of a patient with progressive osteolysis of the vertebral body after undergoing cervical arthroplasty for management of a refractory radiculopathy. SUMMARY OF BACKGROUND DATA: Since the Food and Drug Administration's (FDA) approval of cervical arthroplasty devices in 2007, many surgeons have incorporated this technology into clinical practice. As arthroplasty becomes more widespread, complications unique to this technology are inevitable. To date, only a limited number of complications have been reported in the literature suggesting the safety of this device. To the authors' knowledge, this report represents the first complication of osteolysis from a keel based arthroplasty device. METHODS: A 30-year-old man underwent an uneventful C5-C6 total disc arthroplasty with initial benefit. Progressively worsening neck pain prompted repeat imaging at 9 and 15 months, which showed a progressive osteolytic process in the vicinity of the keel of the superior alloy endplate. This necessitated exploration of the surgical site, explantation of the implant and conversion of the disc arthroplasty to an arthrodesis. RESULTS: Examination of the osteolytic area did not reveal any gross abnormalities. Testing of the device by the manufacturer did not reveal any defects. A comprehensive infectious workup was negative. The osteolytic process halted after the explantation of the device. A bony arthrodesis was achieved at 6 months and the patient remains symptom free 29 months after the initial procedure and 14 months after the revision. CONCLUSION: This report illustrates an exceptional case of a progressive osteolysis with a keel based arthroplasty device. An immune mediated osteolytic process appears to be a plausible explanation for the clinical symptoms and radiographic progression seen in this case. Given the years of use of the ProDisc-C since its FDA approval in 2007, complications with this device are rare. This represents the first reported case of osteolysis from such an implant.

Management of unilateral cervical radiculopathy in the military: the cost effectiveness of posterior cervical foraminotomy compared with anterior cervical discectomy and fusion.

OBJECT: To review the cost effectiveness for the management of a unilateral cervical radiculopathy with either posterior cervical foraminotomy (PCF) or anterior cervical discectomy and fusion (ACDF) in military personnel, with a particular focus on time required to return to active-duty service. METHODS: Following internal review board approval, the authors conducted a retrospective review of 38 cases in which patients underwent surgical management of unilateral cervical radiculopathy. Nineteen patients who underwent PCF were matched for age, treatment level, and surgeon to 19 patients who had undergone ACDF. Successful outcome was determined by return to full, unrestricted active-duty military service. The difference in time of return to active duty was compared between the groups. In addition, a cost analysis consisting of direct and indirect costs was used to compare the PCF group to the ACDF group. RESULTS: A total of 21 levels were operated on in each group. There were 17 men and 2 women in the PCF group, whereas all 19 patients in the ACDF group were men. The average age at the time of surgery was 41.5 years (range 27-56 years) and 39.3 years (range 24-52 years) for the PCF and ACDF groups, respectively. There was no statistically significant difference in operating room time, estimated blood loss, or postoperative narcotic refills. Complications included 2 cases of transient recurrent laryngeal nerve palsy in the ACDF group. The average time to return to unrestricted full duty was 4.8 weeks (range 1-8 weeks) in the PCF group and 19.6 weeks (range 12-32 weeks) in the ACDF group, a difference of 14.8 weeks (p < 0.001). The direct costs of each surgery were $3570 for the PCF and $10,078 for the ACDF, a difference of $6508. Based on the 14.8-week difference in time to return to active duty, the indirect cost was calculated to range from $13,586 to $24,045 greater in the ACDF group. Total cost (indirect plus direct) ranged from $20,094 to $30,553 greater in the ACDF group. CONCLUSIONS: In the management of unilateral posterior cervical radiculopathy for military active-duty personnel, PCF offers a benefit relative to ACDF in immediate short-term direct and long-term indirect costs. The indirect cost of a service member away from full, unrestricted active duty 14.8 weeks longer in the ACDF group was the main contributor to this difference.

Arthroplasty in the military: a preliminary experience with ProDisc-C and ProDisc-L.

OBJECT: The introduction of cervical and lumbar arthroplasty has allowed for management of cervical radiculopathy and lumbar degenerative disease in patients with the preservation of motion at the affected segment. While the early clinical outcomes of this technology appear promising, it remains unclear what activity limitations should be imposed after surgery in patients with these implants. This is of particular interest in military personnel, who may be required to return to a rigorous level of activity after surgery. The goals of the FDA trials evaluating various disc arthroplasty devices were to establish safety, efficacy, and equivalency to arthrodesis. Information regarding the level of physical performance attained and restrictions or limitations is lacking, as these were outside the objectives of these trials. Nevertheless, there data are essential for the military surgeon, who is tasked with guiding the postoperative management of patients treated with arthroplasty and returning them to full duty. While there is a single report of clinical results of lumbar arthroplasty in athletes, at this writing, there are no reports of either cervical or lumbar arthroplasty in active duty military personnel. METHODS: The surgical database at a single, tertiary care military treatment facility was queried for all active-duty patients who underwent placement of either a cervical or lumbar arthroplasty device over a 3-year period. The authors performed a retrospective chart review to collect patient and procedural data including blood loss, length of hospital stay, tobacco use, age, rank, complications, and ability to return to full unrestricted active duty. Arthroplasty cohorts were then compared to historical controls of arthrodesis to ascertain differences in the time required to return to full duty. RESULTS: Twelve patients were identified who underwent cervical arthroplasty. All patients returned to unrestricted full duty. This cohort was then compared with 12 patients who had undergone a single-level anterior cervical discectomy and fusion. The average time to return to unrestricted full duty for the arthroplasty group was 10.3 weeks (range 7-13 weeks), whereas that in the fusion group was 16.5 weeks. This difference between these 2 groups was statistically significant (p = 0.008). Twelve patients were identified who underwent lumbar arthroplasty. Ten (83%) of 12 patients in this group returned to unrestricted full duty. In patients who returned to full duty, it took an average of 22.6 weeks (range 12-29 weeks). This cohort was then compared with one in which patients had undergone anterior lumbar interbody fusion. Eight (67%) of 12 patients in the lumbar arthrodesis group returned to unrestricted full duty. In patients who returned to full duty, it took an average of 32.4 weeks (range 25-41 weeks). This difference was not statistically significant (p = 0.156). CONCLUSIONS: The preliminary experience with cervical and lumbar arthroplasty at the authors' institution indicates that arthroplasty is comparable with arthrodesis and may actually expedite return to active duty. Patients are capable of returning to a high level of rigorous training and physical performance. There are no apparent restrictions or limitations that are required after 3 months in the cervical patient and after 6 months in the lumbar patient. Further prospective studies with long-term follow-up are indicated and will be of value when determining the role of arthroplasty compared to arthrodesis in the active-duty population.

Can surgery improve neurological function in penetrating spinal injury? A review of the military and civilian literature and treatment recommendations for military neurosurgeons.

OBJECT: Penetrating spinal injury (PSI), although an infrequent injury in the civilian population, is not an infrequent injury in military conflicts. Throughout military history, the role of surgery in the treatment of PSI has been controversial. The US is currently involved in 2 military campaigns, the hallmark of both being the widespread use of various explosive devices. The authors reviewed the evidence for or against the use of decompressive laminectomy to treat PSI to provide a triservice (US Army, Navy, and Air Force) consensus and treatment recommendations for military neurosurgeons and spine surgeons. METHODS: A US National Library of Medicine PubMed database search that identified all literature dealing with acute management of PSI from military conflicts and civilian urban trauma centers in the post-Vietnam War period was undertaken. RESULTS: Nineteen retrospective case series (11 military and 8 civilian) met the study criteria. Eleven military articles covered a 20-year time span that included 782 patients who suffered either gunshot or blast-related projectile wounds. Four papers included sufficient data that analyzed the effectiveness of surgery compared with nonoperative management, 6 papers concluded that surgery was of no benefit, 2 papers indicated that surgery did have a role, and 3 papers made no comment. Eight civilian articles covered a 9-year time span that included 653 patients with spinal gunshot wounds. Two articles lacked any comparative data because of treatment bias. Two papers concluded that decompressive laminectomy had a beneficial role, 1 paper favored the removal of intracanal bullets between T-12 and L-4, and 5 papers indicated that surgery was of no benefit. CONCLUSIONS: Based on the authors' military and civilian PubMed literature search, most of the evidence suggests that decompressive laminectomy does not improve neurological function in patients with PSI. However, there are serious methodological shortcomings in both literature groups. For this and other reasons, neurosurgeons from the US Air Force, Army, and Navy collectively believe that decompression should still be considered for any patient with an incomplete neurological injury and continued spinal canal compromise, ideally within 24-48 hours of injury; the patient should be stabilized concurrently if it is believed that the spinal injury is unstable. The authors recognize the highly controversial nature of this topic and hope that this literature review and the proposed treatment recommendations will be a valuable resource for deployed neurosurgeons. Ultimately, the deployed neurosurgeon must make the final treatment decision based on his or her opinion of the literature, individual abilities, and facility resources available.

Spinal tumors in children.

Pediatric spine tumors encompass a diverse group of pathologic diagnoses that differ markedly based on the location and age of the child. Children can be affected by primary and metastatic tumors, making the differential diagnosis and treatment options extensive. This article discusses the features of spinal tumors in children based primarily on location: extradural, intradural-extramedullary, and intramedullary tumors. Because this article deals with such a broad topic, detailed descriptions and outcomes of surgical and nonsurgical treatments for each particular tumor are limited. Rather, the key clinical, diagnostic, and therapeutic features of each tumor are discussed.

Long-term maintenance of cervical alignment after occipitocervical and atlantoaxial screw fixation in young children.

OBJECT: Despite decades of surgical experience, the long-term consequences of occipitocervical (OC) and atlantoaxial (C1-2) fusions in children are unknown. The purpose of this study was to determine the long-term effects of these fusions on growth and alignment of the maturing cervical spine. METHODS: A retrospective chart review was conducted for patients 6 years of age or younger (mean 4.7 years, range 1.7-6.8 years) who underwent OC or C1-2 fusion at the Primary Children's Medical Center at the University of Utah within the last 10 years. Immediate postoperative plain radiographs and computed tomography (CT) scans were compared with the most recent plain and dynamic radiographs to assess changes in spinal growth and alignment. Seventeen children met entry criteria for the study. All patients had fusion documented on follow-up radiography or CT scans. At a mean follow up of 28 months, there were no cases of sagittal malalignment (kyphotic or swan-neck deformity), subaxial instability (osteophyte formation or subluxation), or unintended fusion of adjacent levels. The lordotic curvature of the cervical spine increased from a mean of 15 degrees postoperatively to 27 degrees at follow up (p = 0.06). A mean of 34% of the vertical growth of the cervical spine occurred within the fusion segment. When data were analyzed pertaining to a subgroup of five patients who underwent follow-up periods for longer than 48 months (mean 50.2 months, range 48-54 months), similar results were seen. CONCLUSIONS: Preliminary follow-up results indicate that, compared with older children, children 6 years of age or younger undergoing OC or C1-2 fusion are not at an increased risk of spinal deformity or subaxial instability. Longer follow-up periods, during which measurements of the spinal canal are taken, will be necessary to determine precisely how children's spines grow and remodel after an upper cervical spine fusion.

Atlantoaxial transarticular screw fixation: a review of surgical indications, fusion rate, complications, and lessons learned in 191 adult patients.

OBJECT: In this, the first of two articles regarding C1-2 transarticular screw fixation, the authors assessed the rate of fusion, surgery-related complications, and lessons learned after C1-2 transarticular screw fixation in an adult patient series. METHODS: The authors retrospectively reviewed 191 consecutive patients (107 women and 84 men; mean age 49.7 years, range 17-90 years) in whom at least one C1-2 transarticular screw was placed. Overall 353 transarticular screws were placed for trauma (85 patients), rheumatoid arthritis (63 patients), congenital anomaly (26 patients), os odontoideum (four patients), neoplasm (eight patients), and chronic cervical instability (five patients). Among these, 67 transarticular screws were placed in 36 patients as part of an occipitocervical construct. Seventeen patients had undergone 24 posterior C1-2 fusion attempts prior to referral. The mean follow-up period was 15.2 months (range 0.1-106.3 months). Fusion was achieved in 98% of cases followed to commencement of fusion or for at least 24 months. The mean duration until fusion was 9.5 months (range 3-48 months). Complications occurred in 32 patients. Most were minor; however, five patients suffered vertebral artery (VA) injury. One bilateral VA injury resulted in patient death. The others did not result in any permanent neurological sequelae. CONCLUSIONS: Based on this series, the authors have learned important lessons that can improve outcomes and safety. These include techniques to improve screw-related patient positioning, development of optimal instrumentation, improved screw materials and design, and defining the role for stereotactic navigation. Atlantoaxial transarticular screw fixation is highly effective in achieving fusion, and the complication rate is low when performed by properly trained surgeons.

Atlantoaxial transarticular screw fixation: a review of surgical indications, fusion rate, complications, and lessons learned in 67 pediatric patients.

OBJECT: In this, the second of two articles regarding C1-2 transarticular screw fixation, the authors discuss their surgical experience in treating patients 16 years of age and younger, detailing the rate of fusion, complication avoidance, and lessons learned in the pediatric population. METHODS: The authors retrospectively reviewed 67 consecutive patients (23 girls and 44 boys) younger than 16 years of age in whom at least one C1-2 transarticular screw fixation procedure was performed. A total of 127 transarticular screws were placed in these 67 patients whose mean age at time of surgery was 9 years (range 1.7-16 years). The indications for surgery were trauma in 24 patients, os odontoideum in 22 patients, and congenital anomaly in 17 patients. Forty-four patients underwent atlantoaxial fusion and 23 patients underwent occipitocervical fusion. Two of the 67 patients underwent halo therapy postoperatively. All patients were followed for a minimum of 3 months. In all 67 patients successful fusion was achieved. Complications occurred in seven patients (10.4%), including two vertebral artery injuries. CONCLUSIONS: The use of C1-2 transarticular screw fixation, combined with appropriate atlantoaxial and craniovertebral bone/graft constructs, resulted in a 100% fusion rate in a large consecutive series of pediatric patients. The risks of C1-2 transarticular screw fixation can be minimized in this population by undertaking careful patient selection and meticulous preoperative planning.

False-negative magnetic resonance angiography with extracranial internal carotid artery stenosis: a report of two cases and review of the literature.

Magnetic resonance angiography (MRA) is increasingly used as a noninvasive means to assess internal carotid artery (ICA) stenosis. When used alone, however, MRA may not be sufficiently accurate in certain settings to determine whether ICA disease meets surgical criteria. Although MRA has been recognized to overestimate the degree of stenosis, the authors present two cases in which it severely underestimated arterial stenosis. Two male patients, 70 and 40 years old, respectively, were admitted with crescendo transient ischemic attacks. Their MRA studies suggested nonsurgical lesions of the ICA. After the patients continued to demonstrate clinical evidence of embolic disease, digital subtraction angiography (DSA) was performed on one patient, and the other received a gadolinium contrast-enhanced MRA. These tests revealed critical stenosis in each patient. Each was taken to the operating room for awake carotid endarterectomy with heparin anticoagulation and electroencephalographic monitoring. At surgery, both patients were found to have severely stenosed ICAs with complex plaques. MRA to determine whether ICA stenosis meets surgical criteria may not be sufficiently accurate in certain clinical settings. Additional imaging studies, such as confirmatory digital ultrasonography, MRA with gadolinium contrast, or DSA, may be required to determine the extent of carotid artery stenosis accurately.

Cavernous hemangioma of the skull presenting with subdural hematoma. Case report.

Cavernous hemangioma of the calvaria is a very rare disease, and patients usually present with headaches or a visible skull deformity. Few reports of patients presenting with intradiploic or epidural hemorrhages are found in the literature. No case of an intradural hemorrhage from a cavernous hemangioma of the skull has been reported to date. The authors present the case of a 50-year-old man in whom a symptomatic subdural hematoma (SDH) resulting from a cavernous hemangioma of the calvaria had hemorrhaged and eroded through the inner table of the skull and dura mater. The patient underwent surgery for evacuation of the SDH and resection of the calvarial lesion. Postoperatively, the patient experienced immediate relief of his symptoms and had no clinical or radiological recurrence. Calvarial cavernous hemangiomas should be considered in the differential diagnosis of nontraumatic SDHs. Additionally, skull lesions that present with intracranial hemorrhages must be identified and resected at the time of hematoma evacuation to prevent recurrences.