Posterior Vertebral Column Subtraction Osteotomy for Recurrent Tethered Cord Syndrome: A Multicenter, Retrospective Analysis.

BACKGROUND: Few have explored the safety and efficacy of posterior vertebral column subtraction osteotomy (PVCSO) to treat tethered cord syndrome (TCS). OBJECTIVE: To evaluate surgical outcomes after PVCSO in adults with TCS caused by lipomyelomeningocele, who had undergone a previous detethering procedure(s) that ultimately failed. METHODS: This is a multicenter, retrospective analysis of a prospectively collected cohort. Patients were prospectively enrolled and treated with PVCSO at 2 institutions between January 1, 2011 and December 31, 2018. Inclusion criteria were age ≥18 yr, TCS caused by lipomyelomeningocele, previous detethering surgery, and recurrent symptom progression of less than 2-yr duration. All patients undergoing surgery with a 1-yr minimum follow-up were evaluated. RESULTS: A total of 20 patients (mean age: 36 yr; sex: 15F/5M) met inclusion criteria and were evaluated. At follow-up (mean: 23.3 ± 7.4 mo), symptomatic improvement/resolution was seen in 93% of patients with leg pain, 84% in back pain, 80% in sensory abnormalities, 80% in motor deficits, 55% in bowel incontinence, and 50% in urinary incontinence. Oswestry Disability Index improved from a preoperative mean of 57.7 to 36.6 at last follow-up (P < .01). Mean spinal column height reduction was 23.4 ± 2.7 mm. Four complications occurred: intraoperative durotomy (no reoperation), wound infection, instrumentation failure requiring revision, and new sensory abnormality. CONCLUSION: This is the largest study to date assessing the safety and efficacy of PVCSO in adults with TCS caused by lipomyelomeningocele and prior failed detethering. We found PVCSO to be an excellent extradural approach that may afford definitive treatment in this particularly challenging population.

The effect of renin-angiotensin system blockers on spinal cord dysfunction and imaging features of spinal cord compression in patients with symptomatic cervical spondylosis.

BACKGROUND CONTEXT: Cervical spondylosis may lead to spinal cord compression, poor vascular perfusion, and ultimately, cervical myelopathy. Studies suggest a neuroprotective effect of renin-angiotensin system (RAS) inhibitors in the brain, but limited data exist regarding their impact on the spinal cord. PURPOSE: To investigate whether RAS blockers and other antihypertensive drugs are correlated with preoperative functional status and imaging markers of cord compression in patients with symptomatic cervical spondylosis. STUDY DESIGN: Retrospective observational study. PATIENT SAMPLE: Individuals with symptomatic degenerative cervical stenosis who underwent surgery. OUTCOME MEASURES: Imaging features of spinal cord compression and functional status (modified Japanese Orthopedic Association [mJOA] and Nurick grading scales). METHODS: Two hundred sixty-six operative patients with symptomatic degenerative cervical stenosis were included. Demographic data, comorbidities, antihypertensive medications, and functional status (including mJOA and Nurick grading scales) were collected. We evaluated canal compromise, cord compromise, surface area of T2 signal cord change, and pixel intensity of signal cord change compared with normal cord on T2-weighted magnetic resonance imaging sequences. RESULTS: Of 266 patients, 41.7% were women, 58.3% were men; median age was 57.2 years; 20.6% smoked tobacco; 24.7% had diabetes mellitus. One hundred forty-nine patients (55.8%) had hypertension, 142 (95.3%) of these were taking antihypertensive medications (37 angiotensin-II receptor blockers [ARBs], 44 angiotensin-converting enzyme inhibitors, and 61 other medications). Patients treated with ARBs displayed a higher signal intensity ratio (ie, less signal intensity change in the compressed cord area) compared with untreated patients without hypertension (p=.004). Patients with hypertension had worse preoperative mJOA and Nurick scores than those without (p<.001). In the multivariate analysis, ARBs remained an independent beneficial factor for lower signal intensity change (p=.04), whereas hypertension remained a risk factor for worse preoperative neurological status (p<.01). CONCLUSIONS: In our study, patients with hypertension who were treated with RAS inhibitors had decreased T2-weighted signal intensity change than untreated patients without hypertension. Patients with hypertension also had worse preoperative functional status. Prospective case-control studies may deepen understanding of RAS modulators in the imaging and functional status of chronic spinal cord compression.

First spine surgery utilizing real-time image-guided robotic assistance.

Robotics in spinal surgery has significant potential benefits for both surgeons and patients, including reduced surgeon fatigue, improved screw accuracy, decreased radiation exposure, greater options for minimally invasive surgery, and less time required to train residents on techniques that can have steep learning curves. However, previous robotic systems have several drawbacks, which are addressed by the innovative ExcelsiusGPSTM robotic system. The robot is secured to the operating room floor, not the patient. It has a rigid external arm that facilitates direct transpedicular drilling and screw placement, without requiring K-wires. In addition, the ExcelsisuGPSTM has integrated neuronavigation, not present in other systems. It also has surveillance marker that immediately alerts the surgeon in the event of loss of registration, and a lateral force meter to alert the surgeon in the event of skiving. Here, we present the first spinal surgery performed with the assistance of this newly approved robot. The surgery was performed with excellent screw placement, minimal radiation exposure to the patient and surgeon, and the patient had a favorable outcome. We report the first operative case with the ExcelsisuGPSTM, and the first spine surgery utilizing real-time image-guided robotic assistance.

Biomechanical evaluation of interbody fixation with secondary augmentation: lateral lumbar interbody fusion versus posterior lumbar interbody fusion.

BACKGROUND: Many approaches to the lumbar spine have been developed for interbody fusion. The biomechanical profile of each interbody fusion device is determined by the anatomical approach and the type of supplemental internal fixation. Lateral lumbar interbody fusion (LLIF) was developed as a minimally invasive technique for introducing hardware with higher profiles and wider widths, compared with that for the posterior lumbar interbody fusion (PLIF) approach. However, the biomechanics of the interbody fusion construct used in the LLIF approach have not been rigorously evaluated, especially in the presence of secondary augmentation. METHODS: Spinal stability of 21 cadaveric lumbar specimens was compared using standard nondestructive flexibility studies [mean range of motion (ROM), lax zone (LZ), stiff zone (SZ) in flexion-extension, lateral bending, and axial rotation]. Non-paired comparisons were made among four conditions: (I) intact; (II) with unilateral interbody + bilateral pedicle screws (BPS) using the LLIF approach (referred to as the LLIF construct); (III) with bilateral interbody + BPS using the PLIF approach (referred to as the PLIF construct); and (IV) with no lumbar interbody fusion (LIF) + BPS (referred to as the no-LIF construct). RESULTS: With bilateral pedicle screw-rod fixation, stability was equivalent between PLIF and LLIF constructs in lateral bending and flexion-extension. PLIF and LLIF constructs had similar biomechanical profiles, with a trend toward less ROM in axial rotation for the LLIF construct. CONCLUSIONS: LLIF and PLIF constructs had similar stabilizing effects.

Technique: open lumbar decompression and fusion with the Excelsius GPS robot.

The Excelsius GPS (Globus Medical, Inc.) was approved by the FDA in 2017. This novel robot allows for real-time intraoperative imaging, registration, and direct screw insertion through a rigid external arm-without the need for interspinous clamps or K-wires. The authors present one of the first operative cases utilizing the Excelsius GPS robotic system in spinal surgery. A 75-year-old man presented with severe lower back pain and left leg radiculopathy. He had previously undergone 3 decompressive surgeries from L3 to L5, with evidence of instability and loss of sagittal balance. Robotic assistance was utilized to perform a revision decompression with instrumented fusion from L3 to S1. The usage of robotic assistance in spinal surgery may be an invaluable resource in minimally invasive cases, minimizing the need for fluoroscopy, or in those with abnormal anatomical landmarks. The video can be found here: https://youtu.be/yVI-sJWf9Iw .

Pedicle screw accuracy assessment in ExcelsiusGPS® robotic spine surgery: evaluation of deviation from pre-planned trajectory.

BACKGROUND: The ExcelsiusGPS® (Globus Medical, Inc., Audubon, PA) is a next-generation spine surgery robotic system recently approved for use in the United States. The objective of the current study is to assess pedicle screw accuracy and clinical outcomes among two of the first operative cases utilizing the ExcelsiusGPS® robotic system and describe a novel metric to quantify screw deviation. METHODS: Two patients who underwent lumbar fusion at a single institution with the ExcelsiusGPS® surgical robot were included. Pre-operative trajectory planning was performed from an intra-operative CT scan using the O-arm (Medtronic, Inc., Minneapolis, MN). After robotic-assisted screw implantation, a post-operative CT scan was obtained to confirm ideal screw placement and accuracy with the planned trajectory. A novel pedicle screw accuracy algorithm was devised to measure screw tip/tail deviation distance and angular offset on axial and sagittal planes. Screw accuracy was concurrently determined by a blinded neuroradiologist using the traditional Gertzbein-Robbins method. Clinical variables such as symptomatology, operative data, and post-operative follow-up were also collected. RESULTS: Eight pedicle screws were placed in two L4-L5 fusion cases. Mean screw tip deviation was 2.1 mm (range 0.8-5.2 mm), mean tail deviation was 3.2 mm (range 0.9-5.4 mm), and mean angular offset was 2.4 degrees (range 0.7-3.8 degrees). All eight screws were accurately placed based on the Gertzbein-Robbins scale (88% Grade A and 12% Grade B). There were no cases of screw revision or new post-operative deficit. Both patients experienced improvement in Frankel grade and Karnofsky Performance Status (KPS) score by 6 weeks post-op. CONCLUSION: The ExcelsiusGPS® robot allows for precise execution of an intended pre-planned trajectory and accurate screw placement in the first patients to undergo robotic-assisted fusion with this technology.

Far-Lateral Approach Without Drilling the Occipital Condyle for Vertebral Artery-Posterior Inferior Cerebellar Artery Aneurysms.

BACKGROUND: The far-lateral transcondylar surgical approach is often used to clip vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms. The role of condyle resection during this approach is controversial. OBJECTIVE: To evaluate patient outcomes in patients with VA-PICA aneurysms in whom drilling the occipital condyle was not necessary. METHODS: Between May 2005 and December 2012, a total of 56 consecutive patients with incidental or ruptured VA-PICA aneurysms underwent surgery with a far-lateral approach without condylar resection. Clinical presentation, surgical reports, presurgery and postsurgery radiological examinations, and clinical follow-up reports were assessed. Anatomic aneurysm location was analyzed through angiography or computed tomography angiography. We compared postsurgical Glasgow Outcome Scale scores, modified Rankin Scale scores, and morbidity in 2 groups: those with aneurysms in the anterior medullary segment and those with aneurysms in the lateral medullary segment. RESULTS: The predominant presentation was subarachnoid hemorrhage in 34 patients (60.7%). Most aneurysms (n = 27 [48.2%]) were located in the lateral medullary segment of the PICA, followed by the anterior medullary segment (n = 25 [44.6%]). Total aneurysm occlusion was achieved in 100% of patients, and bypass techniques were necessary in 3 patients (5.4%). Fifty-two patients (92.8%) had Glasgow Outcome Scale scores of 4 or 5 postsurgery. CONCLUSIONS: A far-lateral approach that leaves the occipital condyle intact is adequate for treating most patients with VA-PICA aneurysms.

Occipitocervical Fixation: A Single Surgeon's Experience With 120 Patients.

BACKGROUND: Occipitocervical junction instability can lead to serious neurological injury or death. Open surgical fixation is often necessary to provide definitive stabilization. However, long-term results are limited to small case series. OBJECTIVE: To review the causes of occipitocervical instability, discuss the indications for surgical intervention, and evaluate long-term surgical outcomes after occipitocervical fixation. METHODS: The charts of all patients undergoing posterior surgical fixation of the occipitocervical junction by the senior author were retrospectively reviewed. A total of 120 consecutive patients were identified for analysis. Patient demographic characteristics, occipitocervical junction pathology, surgical indications, and clinical and radiographic outcomes are reported. RESULTS: The study population consisted of 64 male and 56 female patients with a mean age of 39.9 years (range, 7 months to 88 years). Trauma was the most common cause of instability, occurring in 56 patients (47%). Ninety patients (75%) were treated with screw/rod constructs; wiring was used in 30 patients (25%). The median number of fixated segments was 5 (O-C4). Structural bone grafts were implanted in all patients (100%). Preoperative neurological deficits were present in 83 patients (69%); 91% of those patients improved with surgery. Mean follow-up was 35.1 ± 27.4 months (range, 0-123 months). Two patients died, and 10 were lost to follow-up before the end of the 6-month follow-up period. Fusion was confirmed in 107 patients (89.1%). The overall complication rate was 10%, including 3 patients with vertebral artery injuries and 2 patients who required revision surgery. CONCLUSION: Occipitocervical fixation is a durable treatment option with acceptable morbidity for patients with occipitocervical instability. ABBREVIATIONS: AIS, American Spinal Injury Association Impairment ScaleCVJ, craniovertebral junctionmJOAS, modified Japanese Orthopaedic Association ScaleNLI, neurological level of injurySCI, spinal cord injury.

Effects of Anterior Plating on Clinical Outcomes of Anterior Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective review. OBJECTIVE: To compare surgical outcomes of patients who have undergone anterior lumbar interbody fusion (ALIF) with and without plating. SUMMARY OF BACKGROUND DATA: In biomechanical testing, ALIF constructs supplemented with plating (ALIFP) reduce range of motion and increase construct stiffness compared with ALIF alone. However, whether ALIFP constructs translate into improved clinical outcomes over ALIF alone is unknown. METHODS: From 2004 through 2010, 231 patients underwent ALIF with (146) or without (85) plating. Eight patients lost to follow up were excluded from final evaluation. Patients' records were evaluated retrospectively for demographics, complications, and outcomes. RESULTS: At a mean follow-up of 13.7 months (range, 1-108 mo), the mean Economic, Functional, and Total Prolo scores for ALIF patients were 4.23, 3.63, and 7.87, respectively. The mean Oswestry Disability Index (ODI) was 24%. At a mean follow-up of 11.2 months (range, 1-93 mo), the mean Economic, Functional, and Total Prolo scores for ALIFP patients were 4.28, 3.67, and 7.95, respectively. The mean ODI was 22.9%. There was no significant difference between rate of complications or Prolo scores or ODI between the 2 groups (t test). Neither diabetes, hypertension, smoking, sex, nor age older than 55 years was significantly related to whether patients had higher Prolo scores with or without plating. Patients with a normal body mass index and ALIF had significantly better Prolo Economic scores and total scores than patients with a normal body mass index and ALIFP (P=0.04 and 0.02, independent samples t test). Patients were also stratified by surgical indication for surgery, and there was no significant difference in Prolo scores or ODI for patients who underwent ALIF alone versus ALIFP. CONCLUSIONS: Even when stratified by indication for surgery, anterior plating does not seem to improve Prolo scores or ODI, suggesting that not all patients undergoing ALIF require plating.

The Influence of Common Medical Conditions on the Outcome of Anterior Lumbar Interbody Fusion.

STUDY DESIGN: The authors retrospectively reviewed a consecutive series of 231 patients with anterior lumbar interbody fusion (ALIF). OBJECTIVE: To determine the correlations among common medical conditions, demographics, and the natural history of lumbar surgery with outcomes of ALIF. SUMMARY OF BACKGROUND DATA: Multiple spinal disorders are treated with ALIF with excellent success rates. Nonetheless, adverse outcomes and complications related to patients' overall demographics, comorbidities, or cigarette smoking have been reported. METHODS: The age, sex, body mass index (BMI), comorbidities, history of smoking or previous lumbar surgery, operative parameters, and complications of 231 patients who underwent ALIF were analyzed. Regression analyses of all variables with complications and surgical outcomes based on total Prolo scores were performed. Two models predicting Prolo outcome score were generated. The first model used BMI and sex interaction, whereas the second model used sex, level of surgery, presence of diabetes mellitus, and BMI as variables. RESULTS: At follow-up, the rate of successful fusion was 99%. The overall complication rate was 13.8%, 1.8% of which occurred intraoperatively and 12% during follow-up. The incidence of complications failed to correlate with demographics, comorbidities, smoking, or previous lumbar surgery (P>0.5). ALIF at T12-L4 was the only factor significantly associated with poor patient outcomes (P=0.024). Both models successfully predicted outcome (P=0.05), although the second model did so only for males. CONCLUSIONS: Surgical level of ALIF correlated with poor patient outcomes as measured by Prolo functional scale. BMI emerged as a significant predictor of Prolo total score. Both multivariate models also successfully predicted outcomes. Surgical or follow-up complications were not associated with patients' preoperative status.

Surgical Management of a Patient With Thoracic Spinal Cord Herniation: Case Report.

BACKGROUND AND IMPORTANCE: Thoracic spinal cord herniation (TSCH) is rare and likely underdiagnosed. It is characterized by ventral herniation of the spinal cord through a dural defect, effacement of the anterior subarachnoid space, and increased posterior subarachnoid space. We present here a case of TSCH diagnosed and surgically treated at Barrow Neurological Institute, along with supplemental intraoperative video. CLINICAL PRESENTATION: A 61-year-old man with a history of progressive myelopathy causing left lower-extremity weakness with associated numbness, impaired gait, foot drop, incontinence, and sexual impotence was referred without any previous treatment. Computed tomographic myelography and magnetic resonance imaging of the thoracic spine showed ventral spinal cord herniation at T3-T4. Neurological monitoring was recorded preoperatively and intraoperatively. The patient underwent left-sided posterolateral exploration via T3-T4 laminectomies and costotransversectomy for intradural cord release/detethering of the spinal cord with additional superior and inferior extension and repair of the dural defect. Arthrodesis was not considered necessary. After cord release, motor evoked potentials showed immediate improvement from baseline. Dural duplication was considered the cause of TSCH in this case. Total reduction of herniation was evident in postoperative images. The postoperative course was uneventful, and at the last follow-up, the patient had regained ambulation and sphincter control. CONCLUSION: Anterior displacement of the thoracic spinal cord should elicit consideration of herniation to prevent misdiagnosis and inadequate surgery. Surgical cord release and enlargement of the dural defect are safe and associated with good clinical outcomes.

Persistent Outpatient Hypertension Is Independently Associated with Spinal Cord Dysfunction and Imaging Characteristics of Spinal Cord Damage among Patients with Cervical Spondylosis.

OBJECTIVE: Hypertension and cervical spondylosis are diseases of the adult population that are approaching near pandemic proportions. However, the interactions between these two disease processes are poorly understood. We set out to determine the associations among systemic hypertension, clinical status, and imaging findings of spinal cord damage for patients with cervical stenosis. METHODS: A retrospective chart review was performed on patients with symptomatic cervical stenosis related to degenerative disease and divided on the basis of outpatient blood pressure control (normal <140/<90 mm Hg). Sagittal T2-weighted magnetic resonance imaging (MRI) of the cervical spine was analyzed to determine the degree of maximal canal stenosis (MCS; %), surface area of increased signal intensity (ISI; cm(2)), and signal intensity ratio (SIR). Functional status was evaluated using the modified Japanese Orthopaedic Association (mJOA) scale and the Nurick scale. RESULTS: One hundred twenty-two patients were identified (64 hypertensive, 58 nonhypertensive). Likelihood of ISI was higher in hypertensive patients (P < 0.05). Average ISI was significantly higher in patients with uncontrolled blood pressure (P = 0.02) despite MCS being identical between the two groups. The mJOA and Nurick scores were worse for patients with systemic hypertension (P < 0.02). Diabetes mellitus and smoking history did not affect these findings. CONCLUSIONS: Persistent hypertension in outpatients is associated with worsened clinical status and increased markers of spinal cord damage on MRI. Perioperative management of blood pressure may serve to improve clinical outcomes. Larger prospective trials are necessary to further validate these findings.

Cervical spinal cord infarction after cervical spine decompressive surgery.

OBJECTIVE: To report five patients who underwent cervical decompressive surgeries and developed persistent postoperative neurologic deficits compatible with spinal cord infarctions and evaluate causes for these rare complications. METHODS: The clinical courses and imaging studies of five patients were retrospectively analyzed. Imaging findings, types of surgeries, vascular compromise or risk factors, hypotensive episodes, intraoperative somatosensory evoked potentials, concomitant brain infarctions, and clinical degree and radiographic extent of spinal cord infarction were studied. The presence of spinal cord infarction was determined by clinical course and imaging evaluation. RESULTS: All five patients had antecedent cervical cord region vascular compromise or generalized vascular risk factors. Four patients developed hypotensive episodes, two intraoperatively and two postoperatively. None of the four patients with hypotensive episodes had imaging or clinical evidence of concomitant brain infarctions. CONCLUSIONS: Neuroimaging evaluation of spinal cord infarction after decompressive surgery is done to exclude spinal cord compression, to ensure adequate surgical decompression, and to confirm infarction by imaging. Antecedent, unrecognized preoperative vascular compromise may be a significant contributor to spinal cord infarction by itself or in combination with hypotension.

Pharmacophysiology of bone and spinal fusion.

BACKGROUND CONTEXT: In recent years, the number of complex spinal surgeries has increased significantly in the elderly population, where the prevalence of low bone density is highest. Consequently, spine surgeons often treat osteoporotic patients who are associated with higher rates of instrumentation failure. Therefore, establishing a successful fusion requires an appropriate substrate for bone formation and local bone remodeling. The fusion process can be supported by therapies that seek to shift the balance of bone homeostasis to increased formation and reduced resorption. PURPOSE: Thorough understanding of the physiology of bone formation and adjunctive therapies can help improve fusion rates. Therefore, we present a thorough review of the latest pharmacologic agents used to enhance bone strength and surgical spinal fusion. METHODS: Systematic review of literature. RESULTS: Current knowledge on bone physiology has led to the development of several pharmacologic agents that enhance bone formation and strengthen the human skeleton. At present, natural supplements of vitamin D and calcium or synthetic medications like bisphosphonates are widely used before and after spine surgeries to enhance bone fusion. Additional physiologic agents, including testosterone, parathyroid hormone, calcitonin, and growth hormone, have been shown to improve bone mass density or spinal fusion in both animal and human studies. As in other medical fields, gene therapy has shown viability and promise with the use of both viral and nonviral vectors. CONCLUSIONS: Through the understanding of bone physiology, numerous natural and synthetic pharmacologic agents have been developed to enhance the body's skeleton and to improve outcomes of spinal fusion surgery.

Comparative analysis of isocentric 3-dimensional C-arm fluoroscopy and biplanar fluoroscopy for anterior screw fixation in odontoid fractures.

STUDY DESIGN: Retrospective clinical study. OBJECTIVE: To compare long-term radiographic and clinical outcomes of patients undergoing anterior odontoid screw placement using traditional biplanar fluoroscopy or isocentric 3-dimensional C-arm (iso-C) fluoroscopy-assisted techniques. SUMMARY OF BACKGROUND DATA: Anterior screw fixation of odontoid fractures preserves motion at the C1-C2 joint, but accurate screw positioning is essential for successful outcomes. Biplanar fluoroscopy image guidance is most often used; however, iso-C imaging improves the ease and accuracy of screw placement with less radiation exposure. METHODS: Fifty-one patients underwent anterior odontoid screw fixation for type II (48 patients) and rostral type III fractures (3 patients). Procedures were guided by biplanar fluoroscopy in 25 (49%) patients, and with iso-C assistance in 26 (51%). Length of surgery, complications, and clinical outcomes based on the Smiley-Webster score were evaluated. Computed tomography confirmed adequate screw placement. Follow-up ranged from 3 to 9 months. RESULTS: At 3-month follow-up, screw position and fusion across the fracture were evident in 87% of the cases treated with biplanar fluoroscopy and in 100% treated by iso-C. The average outcome score in the iso-C group was superior to that of the biplanar group (1.08 vs. 1.33, respectively), although not statistically significant. At last follow-up, the rate of successful fusion was 88% in the biplanar group and 95% in the iso-C group. Length of surgery was significantly lower in the iso-C group compared with the biplanar group (P=0.05). The significantly longer preparation time in the iso-C group (P=0.04) accounted for no overall difference in total operating room occupancy time between the 2 groups. CONCLUSIONS: Iso-C significantly decreased surgical time. At last follow-up iso-C assistance was associated with improved rates of radiographic fusion with comparable outcome and complication profiles. This series represents the largest cohort of patients treated with intraoperative real-time navigation assistance for odontoid fractures.

Biomechanics of lumbar cortical screw-rod fixation versus pedicle screw-rod fixation with and without interbody support.

STUDY DESIGN: Seven different combinations of posterior screw fixation, with or without interbody support, were compared in vitro using nondestructive flexibility tests. OBJECTIVE: To study the biomechanical behavior of a new cortical screw (CS) fixation construct relative to the traditional pedicle screw (PS) construct. SUMMARY OF BACKGROUND DATA: The CS is an alternative to the PS for posterior fixation of the lumbar spine. The CS trajectory is more sagittally and cranially oriented than the PS, being anchored in the pars interarticularis. Like PS fixation, CS fixation uses interconnecting rods fastened with top-locking connectors. Stability after bilateral CS fixation was compared with stability after bilateral PS fixation in the setting of intact disc and with direct lateral interbody fixation (DLIF) or transforaminal lateral interbody fixation (TLIF) support. METHODS: Standard nondestructive flexibility tests were performed in cadaveric lumbar specimens, allowing non-paired comparisons of specific conditions from 28 specimens (4 groups of 7) within a larger experiment of multiple hardware configurations. Condition tested and group from which results originated were as follows: (1) intact (all groups); (2) with L3-L4 bilateral PS-rods (group 1); (3) with bilateral CS-rods (group 2); (4) with DLIF (group 3); (5) with DLIF + CS-rods (group 4); (6) with DLIF + PS-rods (group 3); (7) with TLIF + CS-rods (group 2), and (8) with TLIF + PS-rods (group 2). To assess spinal stability, the mean range of motion, lax zone, and stiff zone at L3-L4 were compared during flexion-extension, lateral bending, and axial rotation. RESULTS: With intact disc, stability was equivalent after PS-rod and CS-rod fixation, except that PS-rod fixation was stiffer during axial rotation. With DLIF support, there was no significant difference in stability between PS-rod and CS-rod fixation. With TLIF support, PS-rod fixation was stiffer than CS-rod fixation during lateral bending. CONCLUSION: Bilateral CS-rod fixation provided about the same stability in cadaveric specimens as PS-rod fixation regardless of the presence of interbody, TLIF, or DLIF support.

Cerebral revascularization and carotid artery resection at the skull base for treatment of advanced head and neck malignancies.

OBJECT: Resection of cancer and the involved artery in the neck has been applied with some success, but the indications for such an aggressive approach at the skull base are less well defined. The authors therefore evaluated the outcomes of advanced skull base malignancies in patients who were treated with bypass and resection of the internal carotid artery (ICA). METHODS: The authors retrospectively reviewed the charts of all patients with advanced head and neck cancers who underwent ICA sacrifice with revascularization in which an extracranial-intracranial bypass was used between 1995 and 2010 at the Barrow Neurological Institute. RESULTS: Eighteen patients (11 male and 7 female patients; mean age 46 years, range 7-69 years) were identified. There were 4 sarcomas and 14 carcinomas that involved the ICA at the skull base. All patients underwent ICA sacrifice with revascularization. One patient died of a stroke after revascularization. A second patient died of the effects of a fistula between the oral and cranial cavities (surgery-related mortality rate 11.1%). Eight months after the operation, 1 patient developed occlusion of the bypass and died. Complications associated with the bypass surgery included 1 case of subdural hematoma (SDH) with blindness, 1 case of status epilepticus, and 1 case of asymptomatic bypass occlusion (bypass-related morbidity 16.7%). Complications associated with tumor resection included 3 cases of CSF leakage requiring repair and shunting, 1 case of hydrocephalus requiring shunting, 1 case of SDH, and 1 case of contralateral ICA injury requiring a bypass (tumor resection morbidity rate 33.3%). In 1 patient treated with adjuvant therapy before surgery, the authors identified only a radiation effect and no tumor on resection. In a second patient the bypass was occluded, and her tumor was not resected. The other 16 patients underwent gross-total resection of their tumor. Excluding the surgery-related deaths, the mean and median lengths of survival in this series were 13.2 and 8.3 months, respectively (range 1.5-48 months). Including the surgery-related deaths, the mean and median lengths of survival were 11.8 and 8 months, respectively (range 17 days-48 months). At last follow-up all patients had died of cancer or cancer-related causes. CONCLUSIONS: Despite maximal surgical intervention, including ICA sacrifice at the skull base with revascularization, patient survival was dismal, and the complication rate was significant. The authors no longer advocate such an aggressive approach in this patient population. On rare occasions, however, such an approach may be considered for low-grade malignancies.

Fedor Krause: the first systematic use of X-rays in neurosurgery.

Within a few months of Wilhelm Conrad Röntgen's discovery of x-rays in 1895, Fedor Krause acquired an x-ray apparatus and began to use it in his daily interactions with patients and for diagnosis. He was the first neurosurgeon to use x-rays methodically and systematically. In 1908 Krause published the first volume of text on neurosurgery, Chirurgie des Gehirns und Rückenmarks (Surgery of the Brain and Spinal Cord), which was translated into English in 1909. The second volume followed in 1911. This was the first published multivolume text totally devoted to neurosurgery. Although Krause excelled in and promoted neurosurgery, he believed that surgeons should excel at general surgery. Importantly, Krause was inclined to adopt technology that he believed could be helpful in surgery. His 1908 text was the first neurosurgical text to contain a specific chapter on x-rays ("Radiographie") that showed roentgenograms of neurosurgical procedures and pathology. After the revolutionary discovery of x-rays by Röntgen, many prominent neurosurgeons seemed pessimistic about the use of x-rays for anything more than trauma or fractures. Krause immediately seized on its use to guide and monitor ventricular drainage and especially for the diagnosis of tumors of the skull base. The x-ray images contained in Krause's "Radiographie" chapter provide a seminal view into the adoption of new technology and the development of neurosurgical technique and are part of neurosurgery's heritage.

Evaluation of operative procedures for symptomatic outcome after decompression surgery for Chiari type I malformation.

The wide spectrum of symptoms and radiographic findings in patients with Chiari I malformation makes the decision to proceed with intervention controversial. We evaluated symptomatic outcomes using diverse surgical techniques in 104 patients who underwent decompression surgery. The symptoms of most patients improved. Patients with syringomyelia showed less symptomatic improvement; however, syringomyelia was not associated with postoperative symptomatic worsening. Durotomy was performed in 97.1% and arachnoid opening was performed in 60.6% with visualization of the fourth ventricle in 51.9% of patients. Neither arachnoid opening nor fourth ventricle visualization was associated with the clinical outcome. Duraplasty was performed in 94.2% of patients. A Chiari plate was used in 13.4% of patients and was associated with favorable outcomes. Use of postoperative steroids or muscle relaxants was not associated with outcome. Syringomyelia showed a 62.5% improvement rate on postoperative MRI. In conclusion, bony decompression and dural opening are important aspects of Chiari I surgery, with symptomatic improvement observed in most patients.

Dysphagia after anterior cervical spine surgery: incidence and risk factors.

OBJECTIVE: To evaluate risk factors for the development of dysphagia after anterior cervical surgery. METHODS: The records of 249 patients who underwent anterior cervical surgery were reviewed. The presence and severity of dysphagia were assessed with the Dysphagia Disability Index 6 weeks and 3, 6, and 12 months after surgery. Age; sex; ethnicity; cigarette smoking; previous cervical surgeries; reoperation for same pathology; type of procedure, incision, and instrumentation; number and levels involved; side of procedure, length of surgery; and use of postoperative bracing were analyzed. RESULTS: During the first 6 months after surgery, 27 (10.8%) patients developed dysphagia. From these patients the presence of dysphagia at 6 weeks and at 3 and 6 months was 88.8%, 29.6%, and 7.4%, respectively. By 12 months, dysphagia had resolved in all cases. The mean age of patients with dysphagia was 55 years (SD 12.98) and 50 years (SD 12.07) in patients without dysphagia (P = 0.05). Dysphagic patients had an average of 2.2 (SD 1.15) levels operated compared with 1.84 (SD 0.950) in nondysphagic patients (P = 0.05). Patients who developed dysphagia were most often treated at C4-5 (67%) and C5-6 (81%: P < 0.001). Although mean operative time was slightly longer in patients with dysphagia (186 minutes) compared with those without (169 minutes), the difference was not significant. CONCLUSIONS: In our patients, the incidence of dysphagia was low, and it had completely resolved at 12 months in all cases. Risk factors for dysphagia were multilevel procedures, involvement of C4-5 and C5-6, and age.