The H Laminectomy: Technical Description and Clinical Experience From the First 85 Patients.

BACKGROUND: Over the years, lumbar laminectomy has been widely employed by spinal surgeons for many purposes throughout the spinal canal. The Misonix BoneScalpel relies on ultrasonic energy and allows the surgeon to make precise osteotomies while protecting collateral or adjacent soft tissue structures. Amplification of electric impulses allows the blade in the BoneScalpel to oscillate at very high frequencies, which thus allow it to cut bone with immense amounts of heat, which are then tempered with copious irrigation to prevent overheating. The purpose of this study is to outline and detail an innovative technique while providing insight into the technique's clinical application in a variety of spine surgeries. METHODS: Data were retrospectively collected from medical charts and surgical reports from February 2018 to July 2021 for each surgery in which the ultrasonic scalpel was used to perform the H laminectomy. Baseline demographic information was recorded, including age, gender, laminectomy indication, and the number of levels of laminectomy. RESULTS: A total of 85 patients (64 women, 21 men) were included in this study. The mean age of the patients was 63.7 years. Of those patients, 42.4% underwent H laminectomy for degenerative stenosis without instrumentation, 31.8% for degenerative stenosis with instrumentation, 9.4% for traumatic injuries, and 7.1% for revision surgery with instrumentation. Approximately 55% of patients underwent laminectomy of 2 or more levels, while the rest underwent single-level laminectomy. No patients had a dural tear or cerebrospinal fluid (CSF) leak as a result of the BoneScalpel. CONCLUSIONS: The H laminectomy is another safe and effective way to perform a lumbar laminectomy. The technique has not been previously reported in the literature. No patients experienced a dural tear or CSF leak from the BoneScalpel using the H laminectomy technique. This technique affords the surgeon enhanced control of the dura-ligamentum interface. Even if the surgeon is not very experienced with the BoneScalpel, this technique provides an inherent safety mechanism with constant visualization/tactile feedback of the tip of the instrument and osteotome.

Balance effort, Cone of Economy, and dynamic compensatory mechanisms in common degenerative spinal pathologies.

BACKGROUND: Changes in balance are common in individuals with spinal disorders and may cause falls. Balance efficiency, is the ability of a person to maintain their center of gravity with minimal neuromuscular energy expenditure, oftentimes referred to as Cone of Economy (CoE). CoE balance is defined by two sets of measures taken from the center of mass (CoM) and head: 1) the range-of-sway (RoS) in the coronal and sagittal planes, and 2) the overall sway distance. This allows spine caregivers to assess the severity of a patient's balance, balance pattern, and dynamic posture and record the changes following surgical intervention. Maintenance of balance requires coordination between the central nervous and musculoskeletal systems. RESEARCH QUESTION: To discern differences in balance effort values between common degenerative spinal pathologies and a healthy control group. METHODS: Three-hundred and forty patients with degenerative spinal pathologies: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), sacroiliac dysfunction (SIJD), degenerative lumbar spondylolisthesis (DLS), single-level lumbar degeneration (LD), and failed back syndrome (FBS), and 40 healthy controls were recruited. A functional balance test was performed approximately one week before surgery recorded by 3D video motion capture. RESULTS: Balance effort and compensatory mechanisms were found to be significantly greater in degenerative spinal pathologies patients compared to controls. Head and Center of Mass (CoM) overall sway ranged from 65.22 to 92.78 cm (p < 0.004) and 35.77-53.31 cm (p < 0.001), respectively in degenerative spinal pathologies patients and in comparison to controls (Head: 44.52 cm, CoM: 22.24 cm). Patients with degenerative spinal pathologies presented with greater trunk (1.61-2.98°, p < 0.038), hip (4.25-5.87°, p < 0.049), and knee (4.55-6.09°, p < 0.036) excursion when compared to controls (trunk: 0.95°, hip: 2.97°, and knee: 2.43°). SIGNIFICANCE: The results of this study indicate that patients from a wide variety of degenerative spinal pathologies similarly exhibit markedly diminished balance (and compensatory mechanisms) as indicated by increased sway on a Romberg test and a larger Cone of Economy (CoE) as compared to healthy controls. Balance effort, as measured by overall sway, was found to be approximately double in patients with degenerative spinal pathologies compared to healthy matched controls. Clinicians can compare CoE parameters among symptomatic patients from the different cohorts using the Haddas' CoE classification system to guide their postoperative prognosis.

Fear-avoidance and Patients' Reported Outcomes are Strongly Correlated With Biomechanical Gait Parameters in Cervical Spondylotic Myelopathy Patients.

STUDY DESIGN: This was a prospective cohort study. OBJECTIVE: The aim was to explores whether fear-avoidance is associated with altered gait patterns in cervical spinal myelopathy (CSM) patients. SUMMARY OF BACKGROUND DATA: Fear-avoidance is associated with activity restriction and emotional distress in chronic pain patients and with poorer spine surgery outcomes. In adults with spinal deformity, fear and avoidance correlates with gait pattern disruptions. Patients having CSM also display distorted gait. METHODS: Ninety CSM patients completed the Tampa Scale for Kinesiophobia (TSK) questionnaire, and the Fear-avoidance Beliefs Questionnaire (FABQ). Each patient performed a series of gait trials. Pearson's product correlation analysis was used to determine the relationship between the self-reported fear of movement measures and the objective gait biomechanical data. RESULTS: The TSK total score was correlated with walking speed ( P =0.003), cadence ( P =0.012), stride ( P =0.010) and step ( P =0.036) time, and stride ( P =0.018) and step ( P =0.035) length. The FABQ physical dimension was correlated with walking speed ( P <0.001), cadence ( P <0.001), stride ( P <0.001) and step ( P =0.006) time, stride ( P <0.001) and step ( P <0.001) length, and gait deviation index ( P <0.001). The FABQ work dimension was correlated with walking speed ( P =0.001), cadence ( P =0.001), stride ( P =0.001) and step ( P =0.008) time, and stride ( P =0.014) and step ( P =0.002) length. CONCLUSIONS: These results provide a framework for further investigation of the relationship between psychosocial factors and objectively measured function in patients with CSM. This study demonstrates a strong correlation between fear and avoidance of movement, as measured with the TSK and FABQ and multiple biomechanical gait parameters, as measured with gait analysis. The current results may imply that fear and avoidance may compound and worsen functional deficits arising from CSM, and strongly suggest that fear and avoidance beliefs should be included as a component of presurgical diagnostic process for CSM patients.

The Effect of Surgical Decompression on Functional Balance Testing in Patients With Cervical Spondylotic Myelopathy.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: Quantify the extent of change in dynamic balance and stability in a group of patients with cervical spondylotic myelopathy (CSM) after cervical decompression surgery and to compare them with matched healthy controls. SUMMARY OF BACKGROUND DATA: CSM is a naturally progressive degenerative condition that commonly results in loss of fine motor control in the hands and upper extremities and in gait imbalance. Whereas this was previously thought of as an irreversible condition, more recent studies are demonstrating postoperative improvements in balance and stability. MATERIALS AND METHODS: Thirty subjects with symptomatic CSM and 25 matched asymptomatic controls between the ages of 45 and 75 years underwent functional balance testing using a 3D motion capture system to gather kinematic and spatiotemporal parameters. CSM subjects underwent testing 1 week before surgery and again 3 months postoperatively. RESULTS: Patients with CSM exhibited markedly diminished balance as indicated by increased sway on a Romberg test and requiring significantly more time and a wider stance to complete tandem gait tests. The surgical intervention resulted in improved balance at the 3-month postoperative time point; however, kinematic and spatiotemporal parameters did not completely normalize to the levels observed in asymptomatic controls. CONCLUSIONS: Human motion video capture can be used to robustly quantify balance parameters in the setting of CSM. Compared with healthy controls, such patients exhibited increased standing sway and poorer performance on a tandem gait task. The surgical intervention resulted in significant improvement in many of the measures of functional balance, but overall profiles had not completely returned to normal when measured 3 months after surgery. These data reinforce the importance of operative intervention in the treatment of symptomatic CSM with the goal of halting disease progress but the expectation that balance may actually improve postoperatively.

Functional Balance Testing in Cervical Spondylotic Myelopathy Patients.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: The aim of this study was to quantify the amount of sway associated with maintaining a balanced posture in a group of untreated cervical spondylotic myelopathy (CSM) patients. SUMMARY OF BACKGROUND DATA: Balance is defined as the ability of the human body to maintain its center of mass (COM) within the base of support with minimal postural sway. Sway is the movement of the COM in the horizontal plane when a person is standing in a static position. CSM patients have impaired body balance and proprioceptive loss. METHODS: Thirty-two CSM patients performed a series of functional balance tests a week before surgery. Sixteen healthy controls (HCs) performed a similar balance test. Patients are instructed to stand erect with feet together and eyes opened in their self-perceived balanced and natural position for a full minute. All test subjects were fitted to a full-body reflective markers set and surface electromyography (EMG). RESULTS: CSM patients had more COM sway in the anterior-posterior (CSM: 2.87 cm vs. C: 0.74 cm; P = 0.023), right-left (CSM: 5.16 cm vs. C: 2.51 cm; P = 0.003) directions as well as head sway (anterior-posterior - CSM: 2.17 cm vs. C: 0.82 cm; P = 0.010 and right-left - CSM: 3.66 cm vs. C: 1.69 cm; P = 0.044), more COM (CSM: 44.72 cm vs. HC: 19.26 cm, p = 0.001), and head (Pre: 37.87 cm vs. C: 19.93 cm, P = 0.001) total sway in comparison to controls. CSM patients utilized significantly more muscle activity to maintain static standing, evidenced by the increased trunk and lower extremity muscle activity (multifidus, erector spinae, rectus femoris, and tibialis anterior, P < 0.050) during 1-minute standing. CONCLUSION: In symptomatic CSM patients, COM and head total sway were significantly greater than controls. Individuals with CSM exhibit more trunk and lower extremity muscle activity, and thus expend more neuromuscular energy to maintain a balanced, static standing posture. This study is the first effort to evaluate global balance as a dynamic process in this patient population. LEVEL OF EVIDENCE: 3.

Effect of Cervical Decompression Surgery on Gait in Adult Cervical Spondylotic Myelopathy Patients.

STUDY DESIGN: This is a prospective cohort study. OBJECTIVE: To evaluate the effect of cervical decompression surgery on the biomechanics of the spine and lower extremities in cervical spondylotic myelopathy (CSM) patients and compare with asymptomatic controls. SUMMARY OF BACKGROUND DATA: Difficulties with balance and gait are one of the most common manifestations of CSM. Patients with CSM have a slower gait speed, prolonged double support duration, and reduced cadence compared with healthy controls. Surgical decompression was found to improve clinical outcomes, but conflicting results are noted when examining function. MATERIALS AND METHODS: In total, 25 subjects with symptomatic CSM underwent clinical gait analysis performed a week before (pre) and 3 months after the surgery (post). Clinical gait analysis was performed on 30 matched asymptomatic controls as well. Spine and lower extremity kinematics, spatiotemporal parameters, and clinical outcome were measured. RESULTS: CSM patients demonstrated slower walking speed (P=0.006), reduced cadence (P=0.001), longer step time (P=0.013) wider step width (P=0.001), greater ankle range of motion (ROM) (P=0.019), less hip ROM (P=0.050), increased pelvis (P=0.001), and lumbar spine (P=0.049) ROM compared with controls. Postoperatively CSM patients demonstrated a faster walking speed (P=0.002), increased cadence (P=0.029), longer step length (P=0.015), narrower step width (P=0.004), greater knee (P=0.043), and hip ROM (P=0.007), less pelvis (P=0.002), lumbar spine (P=0.035), and cervical spine (P=0.044) ROM, and improved clinical outcomes (neck pain disability index questionnaire, oswestry disability index, and visual analog scale; P=0.001) compared with their preoperative values. Postsurgical CSM patients did not present with any differences compared with controls, beside pelvis ROM (P=0.019). CONCLUSIONS: Preoperatively, CSM patients clearly showed altered gait parameters compared with controls. However, after cervical decompression surgery, CSM patients exhibited improved gait pattern, spatiotemporal parameters, spine and lower extremity ROM, as well as patient-reported outcomes. Postoperatively, CSM patients did not show major differences in gait when compared with matched asymptomatic controls.

Spine and lower extremity kinematics during gait in patients with cervical spondylotic myelopathy.

BACKGROUND CONTEXT: Cervical spondylotic myelopathy (CSM) typically manifests with a slow, progressive stepwise decline in neurologic function, including hand clumsiness and balance difficulties. Gait disturbances are frequently seen in patients with CSM, with more advanced cases exhibiting a stiff, spastic gait. PURPOSE: To evaluate the spatiotemporal parameters and spine and lower extremity kinematics during the gait cycle of adult patients with CSM before surgical intervention. STUDY DESIGN: Prospective cohort study. PATIENT SAMPLE: Twenty-eight subjects with symptomatic CSM who have been scheduled for surgery and 30 healthy controls (HC). OUTCOME MEASURES: Spine and lower extremity kinematics and spatiotemporal parameters. METHODS: Clinical gait analysis was performed for patients with CSM and HC. The data were analyzed with a one-way analysis of variance. RESULTS: Patients with CSM have significantly more anterior pelvis tilt (CSM: 13.97°, HC: 5.56°), larger lumbar lordosis (CSM: 8.59°, HC: 2.7°), smaller cervical lordosis (CSM: 6.02°, HC: 11.35°), and less head flexion (CSM: 0.69°, HC: 8.66°) at the beginning of the gait cycle. There was a decrease in knee range of motion in patients with CSM compared with controls (CSM: 36.31°, HC: 50.17°). Furthermore, patients with CSM presented with slower walking speed (CSM: 0.81 m/s, HC: 1.05 m/s), decreased cadence (CSM: 95.57 step/m, HC: 107.64 step/m), increased double support time (CSM: 0.40 s, HC: 0.28 s) and stride time (CSM:1.28 s, HC: 1.13 s), shorter stride length (CSM: 1.04 m, HC: 1.18 m) and step length (CSM:0.51 m, HC: 0.58 m), and wider width (CSM: 0.14 m, HC:0.11 m). CONCLUSIONS: Our study shows that patients with CSM enter the gait cycle with a larger anterior pelvic tilt and lumbar lordosis as well as less cervical lordosis and head flexion. As a consequence of these abnormal spinal parameters at the onset of the gait cycle, lower extremity biomechanics are also altered. Our study is the first to demonstrate the relationship between aberrant spinal alignment and lower extremity function. Identification of this interrelationship as well as the specific gait and biomechanical disturbances seen in myelopathic patients can both inform our understanding of the disease and tailor rehabilitation protocols.

Preoperative functional status as a predictor of short-term outcome in adult spinal deformity surgery.

Adult spinal deformity (ASD) may cause severe disability and difficulty with daily activities. The purpose of this study was to investigate the impact of preoperative functional status on 30-day major complication occurrence in ASD surgery. A review of the prospectively-collected American College of Surgeons National Surgical Quality Improvement database was performed for the years 2007-2013. Inclusion criteria were adult patients (over 21years of age) who underwent spinal fusion for ASD. Functional status was defined as "independent" or "dependent" (requiring assistance from another person) for activities of daily living such as bathing, dressing, feeding, toileting, or mobility. The association between functional status and complications (overall and major) was investigated via multivariate analysis. Results are presented as odds ratios (OR) with 95% confidence intervals (CI). A total of 1247 patients met inclusion criteria (94.4% independent and 5.6% dependent patients). The overall 30-day complication rate was 16.0% (15.6% for independent patients and 22.9% for dependent patients, p=0.10); major complications occurred in 9.2% of independent patients and 17.1% for dependent patients (p=0.02). After controlling for patient age, smoking status, preoperative hematocrit, revision status, use of osteotomy, number of levels fused, and operative time, being dependent on another person for activities of daily living was found to be a significant predictor of major complication development (OR 2.09; 95% CI, 1.04-4.20; p=0.03). Depending on others for activities of daily living before undergoing ASD surgery may predict the development of major perioperative complications, increasing the risk by 2-fold compared to independent patients.

Utility of the LevelCheck Algorithm for Decision Support in Vertebral Localization.

STUDY DESIGN: An automatic radiographic labeling algorithm called "LevelCheck" was analyzed as a means of decision support for target localization in spine surgery. The potential clinical utility and scenarios in which LevelCheck is likely to be the most beneficial were assessed in a retrospective clinical data set (398 cases) in terms of expert consensus from a multi-reader study (three spine surgeons). OBJECTIVE: The aim of this study was to evaluate the potential utility of the LevelCheck algorithm for vertebrae localization. SUMMARY OF BACKGROUND DATA: Three hundred ninety-eight intraoperative radiographs and 178 preoperative computed tomographic (CT) images for patients undergoing spine surgery in cervical, thoracic, lumbar regions. METHODS: Vertebral labels annotated in preoperative CT image were overlaid on intraoperative radiographs via 3D-2D registration. Three spine surgeons assessed the radiographs and LevelCheck labeling according to a questionnaire evaluating performance, utility, and suitability to surgical workflow. Geometric accuracy and registration run time were measured for each case. RESULTS: LevelCheck was judged to be helpful in 42.2% of the cases (168/398), to improve confidence in 30.6% of the cases (122/398), and in no case diminished performance (0/398), supporting its potential as an independent check and assistant to decision support in spine surgery. The clinical contexts for which the method was judged most likely to be beneficial included the following scenarios: images with a lack of conspicuous anatomical landmarks; level counting across long spine segments; vertebrae obscured by other anatomy (e.g., shoulders); poor radiographic image quality; and anatomical variations/abnormalities. The method demonstrated 100% geometric accuracy (i.e., overlaid labels within the correct vertebral level in all cases) and did not introduce ambiguity in image interpretation. CONCLUSION: LevelCheck is a potentially useful means of decision support in vertebral level localization in spine surgery. LEVEL OF EVIDENCE: N/A.

Clinical outcomes following sublaminar decompression and instrumented fusion for lumbar degenerative spinal pathology.

Traditional treatment for lumbar stenosis with instability is laminectomy and posterolateral arthrodesis, with or without interbody fusion. However, laminectomies remove the posterior elements and decrease the available surface area for fusion. Therefore, a sublaminar decompression may be a preferred approach for adequate decompression while preserving bone surface area for fusion. A retrospective review of 71 patients who underwent sublaminar decompression in conjunction with instrumented fusion for degenerative spinal disorders at a single institution was performed. Data collected included demographics, preoperative symptoms, operative data, and radiographical measurements of the central canal, lateral recesses, and neural foramina, and fusion outcomes. Paired t-tests were used to test significance of the outcomes. Thirty-one males and 40 females with a median age 60years underwent sublaminar decompression and fusion. A median of two levels were fused. The mean Visual Analog Scale pain score improved from 6.7 preoperatively to 2.9 at last follow-up. The fusion rate was 88%, and the median time to fusion was 11months. Preoperative and postoperative mean thecal sac cross-sectional area, right lateral recess height, left lateral recess height, right foraminal diameter, and left foraminal diameter were 153 and 209mm(2) (p<0.001), 5.9 and 5.9mm (p=0.43), 5.8 and 6.3mm (p=0.027), 4.6 and 5.2mm (p=0.008), and 4.2 and 5.2mm (p<0.001), respectively. Sublaminar decompression provided adequate decompression, with significant increases in thecal sac cross-sectional area and bilateral foraminal diameter. It may be an effective alternative to laminectomy in treating central and foraminal stenosis in conjunction with instrumented fusion.

Epidural spinal compression as an initial presentation of Hodgkin lymphoma.

Classical Hodgkin lymphoma (CHL) commonly arises in lymph nodes and initial presentation with extranodal disease is rare. We report a patient who presented with progressively worsening back pain, lower extremity weakness and numbness concerning for a myelopathic process of uncertain etiology. MRI revealed an epidural soft tissue mass with cord displacement, for which she underwent resection. Histological analysis of the surgical specimen demonstrated CHL. Further investigation revealed an anterior mediastinal mass, consistent with spread from a more typical location.

Lateral access to paravertebral tumors.

Traditional transabdominal and retroperitoneal approaches for paravertebral tumors can be associated with injury to the viscera and lumbar plexus. The authors provide a technical description of a known approach with a new application for the resection of paraspinal tumors using both open and minimally invasive transpsoas techniques and report on 2 illustrative cases. In both cases, gross-total resection of the tumor was achieved and the patients experienced resolution of their presenting neurological symptoms, although one of the patients required 2 extra days of hospitalization due to an asymptomatic retroperitoneal hematoma, which was conservatively managed. The authors conclude that the lateral transpsoas approach is a safe approach for paravertebral tumors and may not require an access surgeon.

Outcome comparison of atlantoaxial fusion with transarticular screws and screw-rod constructs: meta-analysis and review of literature.

STUDY DESIGN: Literature review and meta-analysis. OBJECTIVE: To compare clinical and radiographic outcomes of patients treated with transarticular screws (TASs) and screw-rod constructs (SRCs) for posterior atlantoaxial fusion. BACKGROUND: Modern techniques for C1-C2 fusions include Magerl and Seeman's TAS and SRC using C1 lateral mass screws and C2 pars/pedicle screws as described by Goel and Laheri and later modified by Harms and Melcher. MATERIALS AND METHODS: Online databases were searched for English-language articles between 1986 and April 2011 describing posterior atlantoaxial instrumentation with C1-C2 TAS or SRC. Forty-five studies (2073 patients) treated with TAS and 24 studies (1073 patients) treated with SRC fulfilled inclusion criteria. Standard and formal meta-analysis techniques were used to compare the outcomes. RESULTS: All studies provided class III evidence. There were no differences in 30-day mortality (0.8% vs. 0.6%) or neurological injury (0.2% vs. 0%). There was a higher incidence of vertebral artery injury [4.1% (95% confidence interval (CI), 2.8%-5.4%) vs. 2.0% (95% CI, 1.1%-3.4%); P=0.02] and malpositioned screws [7.1% (95% CI, 5.7%-8.8%) vs. 2.4% (95% CI, 1.1%-4.1%); P<0.001] and a slightly lower rate of fusion with the TAS technique [97.5% (95% CI, 95.9%-98.5%) vs. 94.6% (95% CI, 92.6%-96.1%); P<0.001]. CONCLUSIONS: TAS and SRC are safe and effective treatment options for C1-C2 instability but require a thorough knowledge of atlantoaxial anatomy for successful insertion of screws. Slightly higher rates of fusion and less risk of injury to the vertebral artery during screw placement were observed with the SRC technique. However, differences in graft material and techniques were noted. Prospective, randomized studies with validated radiographic and clinical outcome metrics are necessary for proper comparison of these techniques.

Atlantoaxial fusion with screw-rod constructs: meta-analysis and review of literature.

OBJECTIVE: To review published series describing C1-2 posterior instrumented fusions and summarize clinical and radiographic outcomes of patients treated with screw-rod constructs (SRC). METHODS: Online databases were searched for English-language articles published between 1991 and April 2011 describing posterior atlantoaxial instrumentation with C1-2 SRC. There were 24 studies including 1073 patients treated with SRC that fulfilled inclusion criteria. Meta-analysis techniques were used to compare outcomes. RESULTS: All studies provided class III evidence. The 30-day perioperative mortality rate was 0.6%, and neurologic injury occurred in two patients with vertebral artery injury (VAI) from screw malpositions (0.2%). The incidence of clinically significant screw malpositions was 2.4% (confidence interval [CI], 1.1%-4.1%), the incidence of VAI was 2.0% (CI, 1.1%-3.4%), and the rate of fusion with the SRC technique was 97.5% (CI, 95.9%-98.5%). CONCLUSIONS: SRC is a safe and effective treatment option for C1-2 instability. The low but nonzero incidence of screw malposition and VAI emphasizes the necessity of having a thorough knowledge of atlantoaxial anatomy for successful insertion of screws.

Comparison of screw malposition and vertebral artery injury of C2 pedicle and transarticular screws: meta-analysis and review of the literature.

STUDY DESIGN: Literature review and meta-analysis. OBJECTIVES: To compare the incidence of screw malposition and vertebral artery injury (VAI) with transarticular screws (TAS) and C2 pedicle screws (C2PS) using meta-analysis techniques. SUMMARY OF BACKGROUND DATA: Posterior instrumentation for atlantoaxial fusions can be challenging and risky. Some centers report a higher incidence of VAI with the implantation of TAS compared with C2PS, whereas other data do not support this. METHODS: Online databases were searched for English language articles between 1994 and April 2011 describing the clinical and radiographic outcomes after insertion of C2PS or TAS. Forty-one studies reporting on 3627 TAS and 33 studies describing 2979 C2PS met inclusion criteria for VAI or clinically significant misplacements (VAI, neurological deficits, or misplacements requiring surgical revision), and 36 studies reporting on 3280 TAS and 28 studies describing 2532 C2PS met inclusion criteria for radiographic misplacement outcomes. RESULTS: All studies comprised class III evidence. VAI occurred in 26 of 3627 (0.72%) implanted TAS and in 10 of 2979 (0.34%) implanted C2PS (P=0.01). Clinically significant misplacements occurred in 67 TAS (1.84%) and in 10 C2PS (0.34%; P<0.0001). The point estimate of VAI for TAS was 1.68% [confidence interval (CI), 1.23%-2.29%] and was higher than C2PS (1.09%; CI, 0.73%-1.63%; P=0.01). The point estimate of clinically significant screw malposition for TAS was 2.33% (CI, 1.61%-3.37%) and was higher than that of C2PS (1.15%; CI, 0.77%-1.70%; P<0.001). CONCLUSIONS: With training, experience, and anatomic knowledge, both TAS and C2PS can be inserted accurately and safely. However, improper insertion and VAI can have catastrophic consequences. Our review identified a higher risk of VAI, neurological injury, and clinically significant malpositions with TAS compared with C2PS. These data provide preliminary support for the supposition that C2PS have a lower risk of morbidity.

Risks for hemorrhagic complications after placement of external ventricular drains with early chemical prophylaxis against venous thromboembolisms.

OBJECT: Patients undergoing placement of an external ventricular drain (EVD) are at increased risk for development of venous thromboembolisms (VTEs). Early chemical prophylaxis has been shown to decrease rates of embolism formation, but the risks for bleeding and the optimal time to initiate prophylaxis have not been clearly defined for this patient population. The authors evaluated the safety and risks for bleeding when chemical prophylaxis for VTEs was started within 24 hours of EVD placement. METHODS: To compare rates of hemorrhage among patients who received prophylaxis within 24 hours and those who received it later than 24 hours after admission, the authors conducted an institutional review board-approved retrospective review. Patients were those who had had an EVD placed and postprocedural imaging conducted at Bellevue Hospital, New York, from January 2009 through April 2012. Data collected included demographics, diagnosis, coagulation panel results, time to VTE prophylaxis and imaging, and occurrence of VTEs. The EVD-associated hemorrhages were classified as Grade 0, no hemorrhage; Grade 1, petechial hyperdensity near the drain; Grade 2, hematoma of 1-15 ml; Grade 3, epidural or subdural hematoma greater than 15 ml; or Grade 4, intraventricular hemorrhage or hematoma requiring surgical intervention. RESULTS: Among 99 patients, 111 EVDs had been placed. Low-dose unfractionated heparin had been given within 24 hours of admission (early prophylaxis) to 56 patients and later than 24 hours after admission (delayed prophylaxis) to 55 patients. There were no statistical differences across all grades (0-4) among those who received early prophylaxis (n = 45, 5, 5, 1, and 0, respectively) and those who received delayed prophylaxis (n = 46, 4, 1, 1, and 3, respectively) (p = 0.731). In the early prophylaxis group, 3 VTEs were discovered among 32 of 56 patients screened for clinically suspected VTEs. In the delayed prophylaxis group, 5 VTEs were discovered among 33 of 55 patients screened for clinically suspected VTEs (p = 0.71). CONCLUSIONS: Hemorrhagic complications did not increase when chemical prophylaxis was started within 24 hours of admission. Also, the incidence of VTEs did not differ between patients in the early and delayed prophylaxis groups. Larger randomized controlled trials are probably needed to assess decreases in VTEs with earlier prophylaxis.

Atlantoaxial fusion with transarticular screws: meta-analysis and review of the literature.

OBJECTIVE: To review published series describing C1-2 posterior instrumented fusions and summarize clinical and radiographic outcomes of patients treated with transarticular screw (TAS) fixation. METHODS: Online databases were searched for English-language articles published between 1986 and April 2011 describing posterior atlantoaxial instrumentation with C1-2 TAS fixation. There were 45 studies including 2073 patients treated with TAS that fulfilled inclusion criteria. Meta-analysis techniques were used to calculate outcomes. RESULTS: All studies provided class III evidence. The 30-day perioperative mortality rate was 0.8%, and the incidence of neurologic injury was 0.2%. The incidence of clinically significant malpositioned screws was 7.1% (confidence interval [CI], 5.7%-8.8%), the incidence of vertebral artery injury was 3.1% (CI, 2.3%-4.3%), and the rate of fusion with the TAS technique was 94.6% (CI, 92.6%-96.1%). CONCLUSIONS: TAS fixation is a safe and effective treatment option for C1-2 instability with high rates of fusion (approximately 95%). Screw malposition and vertebral artery injury occurred in approximately 5% of patients. The successful insertion of TAS requires a thorough knowledge of atlantoaxial anatomy.

Is external cervical orthotic bracing necessary after posterior atlantoaxial fusion with modern instrumentation: meta-analysis and review of literature.

BACKGROUND: No guidelines exist regarding external cervical orthoses (ECO) after atlantoaxial fusion. We reviewed published series describing C1-2 posterior instrumented fusions with screw-rod constructs (SRC) or transarticular screws (TAS) and compared rates of fusion with and without postoperative ECO. METHODS: Online databases were searched for English-language articles between 1986 and April 2011 describing ECO use after posterior atlantoaxial instrumentation with SRC or TAS. Eighteen studies describing 947 patients who had SRC (± ECO: 254 of 693 patients), and 33 studies describing 1424 patients with TAS (± ECO: 525 of 899 patients) met inclusion criteria. Meta-analysis techniques were applied to estimate rates of fusion with and without ECO use. RESULTS: All studies provided class III evidence, and no studies directly compared outcomes with or without ECO use. There was no significant difference in the proportion of patients who achieved successful fusion between patients treated with ECO and without ECO for SRC or TAS patients. Point estimates and 95% confidence intervals (CI) for rates of fusion ± ECO were 97.4% (CI: 95.2% to 98.6%) versus 97.9% (CI: 93.6% to 99.3%) for SRC and 93.6% (CI: 90.7% to 95.6%) versus 95.3% (CI: 90.8% to 97.7%) for TAS. There was no correlation between duration of ECO treatment and fusion (dose effect). CONCLUSIONS: After C1-2 fusion with modern instrumentation, ECO may be unnecessary (class III). Some centers recommend ECO use with patients with softer bone quality (class IV). Prospective, randomized studies with validated radiographic and clinical outcome metrics are necessary to determine the utility of ECO after C1-2 fusion and its impact on patient comfort and cost.