Does Navigation Improve Accuracy of Placement of Pedicle Screws in Single-level Lumbar Degenerative Spondylolisthesis?: A Comparison Between Free-hand and Three-dimensional O-Arm Navigation Techniques.

STUDY DESIGN: This was a prospective, nonrandomized study. OBJECTIVES: To assess the accuracy of O-arm navigation-based pedicle screw insertion in lumbar degenerative spondylolisthesis and to compare it with free-hand pedicle screw insertion technique in matched population. SUMMARY OF BACKGROUND DATA: O-arm navigation is latest in navigation technology that can provide real-time intraoperative images in 3 dimensions while placing the pedicle screws to improve intraoperative pedicle screw accuracy. Degenerative lumbar spondylolisthesis is a locally unstable pathology and placement of pedicle screws can cause increased rotation and translation of the vertebral body. However, is this motion detected by the tracker placed across the unstable segment, is a matter of debate. Inability to detect these positional changes can lead to pedicle perforation while inserting screws using navigation. No study has evaluated the role of O-arm navigation in this patient population. MATERIALS AND METHODS: The study population was divided into 2 groups with 19 patients each, one comprising patients who underwent O-arm navigation-based pedicle screw insertion (group 1) and the other comprising patients who underwent free-hand pedicle screw insertion technique (group 2). A total of 152 pedicle screws were implanted in 38 patients for 1-level instrumented fusion for degenerative lumbar spondylolisthesis. Intraoperative 3-dimensional computed tomography scans using the O-arm were obtained for all patients after insertion of pedicle screws. The images were reviewed intraoperatively and postoperatively for the analysis of pedicle breaches. Assessments in either of the group included (i) accuracy of placement of screws; (ii) the rate and direction of perforation; and (iii) the number of segments the perforated screw was away from the navigation tracker. RESULTS: Mean age of patients in group 1 (O-arm navigation-assisted) was 60 years (SD 11.25; range, 37-73 y), whereas in group 2 (free-hand pedicle screw) was 62 years (SD 18.07; range, 36-90 y). Overall anatomic perforation rate was 12.5% (19/152). Individually, group 1 had 14.47% (11/76) of perforations in comparison with 10.53% (8/76) observed in group 2. The difference was not statistically significant. The lateral margin was the most common site of perforation in both group 1 (64%, 7/11) and group 2 (62.5%, 5/8). Functional perforation rate for the series was 3.3% (5/152), with group 1 having 2.63% (2/76) and group 2 having 3.95% (3/76). The rate of perforation (PR) was significantly higher statistically when the tracker was placed 3 or more [PR 37.5% (6/16)] spinal segments away from instrumented segment compared with when it was placed 1 (0%) or 2 [PR 13.89% (5/36)] spinal segments away. Overall, 11 screws (11/152, 7.24%) had grade 2 perforations and had to be revised. No neurological complications were observed in the series. CONCLUSIONS: O-arm navigation does not provide any significant advantage over conventional free-hand pedicle screw insertion technique in patients with single-level degenerative spondylolisthesis. The accuracy is dependent on the distance of the tracker from the level of instrumentation. Lateral perforations are more common because of instability at the instrumented level leading to translation and rotation of the vertebral body while placing pedicle screws leading to preferential lateral trajectory. These lateral perforations could not be prevented by using navigation. However, no significant complications were noted in either technique.

A proposed set of metrics for standardized outcome reporting in the management of low back pain.

BACKGROUND AND PURPOSE: Outcome measurement has been shown to improve performance in several fields of healthcare. This understanding has driven a growing interest in value-based healthcare, where value is defined as outcomes achieved per money spent. While low back pain (LBP) constitutes an enormous burden of disease, no universal set of metrics has yet been accepted to measure and compare outcomes. Here, we aim to define such a set. PATIENTS AND METHODS: An international group of 22 specialists in several disciplines of spine care was assembled to review literature and select LBP outcome metrics through a 6-round modified Delphi process. The scope of the outcome set was degenerative lumbar conditions. RESULTS: Patient-reported metrics include numerical pain scales, lumbar-related function using the Oswestry disability index, health-related quality of life using the EQ-5D-3L questionnaire, and questions assessing work status and analgesic use. Specific common and serious complications are included. Recommended follow-up intervals include 6, 12, and 24 months after initiating treatment, with optional follow-up at 3 months and 5 years. Metrics for risk stratification are selected based on pre-existing tools. INTERPRETATION: The outcome measures recommended here are structured around specific etiologies of LBP, span a patient's entire cycle of care, and allow for risk adjustment. Thus, when implemented, this set can be expected to facilitate meaningful comparisons and ultimately provide a continuous feedback loop, enabling ongoing improvements in quality of care. Much work lies ahead in implementation, revision, and validation of this set, but it is an essential first step toward establishing a community of LBP providers focused on maximizing the value of the care we deliver.

Assembly of α-synuclein and neurodegeneration in the central nervous system of heterozygous M83 mice following the peripheral administration of α-synuclein seeds.

Peripheral administration (oral, intranasal, intraperitoneal, intravenous) of assembled A53T α-synuclein induced synucleinopathy in heterozygous mice transgenic for human mutant A53T α-synuclein (line M83). The same was the case when cerebellar extracts from a case of multiple system atrophy with type II α-synuclein filaments were administered intraperitoneally, intravenously or intramuscularly. We observed abundant immunoreactivity for pS129 α-synuclein in nerve cells and severe motor impairment, resulting in hindlimb paralysis and shortened lifespan. Filaments immunoreactive for pS129 α-synuclein were in evidence. A 70% loss of motor neurons was present five months after an intraperitoneal injection of assembled A53T α-synuclein or cerebellar extract with type II α-synuclein filaments from an individual with a neuropathologically confirmed diagnosis of multiple system atrophy. Microglial cells changed from a predominantly ramified to a dystrophic appearance. Taken together, these findings establish a close relationship between the formation of α-synuclein inclusions in nerve cells and neurodegeneration, accompanied by a shift in microglial cell morphology. Propagation of α-synuclein inclusions depended on the characteristics of both seeds and transgenically expressed protein.

Determination of the patient acceptable symptom state for the Japanese Orthopaedic Association Score in patients undergoing anterior cervical discectomy and fusion for cervical spondylotic myelopathy.

BACKGROUND CONTEXT: The patient acceptable symptom state (PASS) has gained attention as a valuable interpretation tool in spine research. While the PASS for the Japanese Orthopaedic Association (JOA) score has been recently proposed, previous analyses demonstrated a weak discriminative ability for the suggested threshold. PURPOSE: To define the PASS for the JOA score in patients undergoing anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM). STUDY DESIGN: Retrospective review of prospectively collected registry data. PATIENT SAMPLE: 378 patients who underwent ACDF for cervical myelopathy between 2005 and 2014. OUTCOME MEASURES: The main outcome measure was the JOA score. The PASS anchor question was adapted from the NASS questionnaire, "How would you rate the overall results of your treatment?" and the validation question was adapted from same questionnaire, "Has the surgery for your neck condition met your expectation so far?" METHODS: Patients were assessed preoperatively, 6 months and 2 years postoperatively using the JOA. Responses to the anchor question were dichotomized and used as the external criterion in receiver operating characteristics (ROC) analysis to define thresholds on the JOA that corresponded to a PASS at 2 years postoperatively. Sensitivity analyses were carried out for various subgroups (based on age, gender, body mass index, comorbidities), preoperative myelopathy severity, time of follow-up (6 months and 2 years) and an alternate definition of PASS. RESULTS: Of the 378 patients, 312 (83%) completed 2-year follow-up, of which, 78.5% reported their current state as acceptable. The areas under the curve (AUC) for the ROCs were 0.72 to 0.83 for all analyses, indicating a good discriminative ability of the JOA when assessing if a satisfactory state was attained. The PASS threshold was ≥13.25 points at 6 months (AUC 0.74, sensitivity 78%, specificity 59%) and ≥14.25 points at 2 years (AUC 0.76, sensitivity 74%, specificity 66%). Sensitivity analyses revealed that the 14.25-point threshold on the JOA was robust. PASS responders were approximately 6 times more likely to be satisfied (adjusted OR 6.18, 95% CI 2.87-13.30) and 8 times more likely to have their expectation fulfilled (adjusted OR 8.23, 95% CI 3.81-17.77) compared with non-responders. CONCLUSIONS: This study validates the PASS threshold of 14.25 on the JOA in a robust analysis of a large cohort undergoing ACDF. This knowledge will enable clinicians to identify patients who have attained a satisfactory functional status after surgery for CSM and allow researchers to interpret studies utilizing the JOA from a patient-centered perspective.

Defining threshold values on the neck disability index corresponding to a patient acceptable symptom state in patients undergoing elective surgery for degenerative disorders of the cervical spine.

BACKGROUND CONTEXT: The patient acceptable symptom state (PASS) has emerged as a novel tool for interpreting patient-reported outcomes. While the minimal clinically important difference values for various spine outcome instruments have been defined, little is known about the PASS thresholds for these measures. PURPOSE: To define threshold values on the neck disability index (NDI) corresponding to a PASS in patients undergoing surgery for degenerative disorders of the cervical spine. STUDY DESIGN: Retrospective review of prospectively collected registry data. PATIENT SAMPLE: The sample includes 613 patients who underwent anterior cervical discectomy and fusion for degenerative spine conditions between 2005 and 2014. OUTCOME MEASURES: The main outcome measure was the NDI. The PASS anchor question was adapted from the NASS questionnaire, "How would you rate the overall results of your treatment?" and the validation question was adapted from the AAOS cervical spine questionnaire, "Would you have the same treatment again if you had the same condition?" METHODS: Patients were assessed preoperatively, 6 months and 2 years postoperatively using the NDI. Responses to the anchor question were dichotomized and used as the external criterion in receiver operating characteristics analysis to define thresholds on the NDI that corresponded to a PASS at 2 years postoperatively. Sensitivity analyses were carried out for various subgroups (age, gender, BMI, comorbidity status), baseline NDI (tertiles), time of follow-up (6 months and 2 years) and an alternate definition of PASS. RESULTS: Of the 613 patients, 503 (82%) completed 2-year follow-up, of which, 81% reported their current state as acceptable. The areas under the curve (AUC) for the receiver operating characteristics were 0.75 to 0.89 for all analyses, indicating a good ability of the NDI to discriminate between attaining a satisfactory state or not. The PASS threshold was ≤15 points at 6 months (AUC 0.81, sensitivity 73%, specificity 79%) and ≤17 points at 2 years (AUC 0.80, sensitivity 86%, specificity 65%). Sensitivity analyses revealed that the 17-point threshold on the NDI was robust. PASS responders were approximately 12 times more likely to be satisfied (adjusted odds ratio 12.11, 95% confidence intervals 6.96-21.07) and 6 times more willing to undergo surgery again (adjusted odds ratio 6.12, 95% confidence intervals 3.47-10.80) compared to nonresponders. CONCLUSIONS: Patients with a NDI of ≤17 consider their postoperative symptom state to be acceptable. This PASS threshold can be used alongside the minimal clinically important difference when defining treatment success in spine outcomes studies. At the individual level, this threshold provides clinically relevant benchmarks for surgeons when assessing a patient's postoperative recovery.

Salmonella Typhi Vertebral Osteomyelitis and Epidural Abscess.

Salmonella vertebral osteomyelitis is an uncommon complication of Salmonella infection. We report a case of a 57-year-old transgender male who presented with lower back pain for a period of one month following a fall. Physical examination only revealed tenderness over the lower back with no neurological deficits. MRI of the thoracic and lumbar spine revealed a spondylodiscitis at T10-T11 and T12-L1 and right posterior epidural collection at the T9-T10 level. He underwent decompression laminectomy with segmental instrumentation and fusion of T8 to L3 vertebrae. Intraoperatively, he was found to have acute-on-chronic osteomyelitis in T10 and T11, epidural abscess, and discitis in T12-L1. Tissue and wound culture grew Salmonella Typhi and with antibiotics susceptibility guidance he was treated with intravenous ceftriaxone for a period of six weeks. He recovered well with no neurological deficits.

Surgically treated cervical myelopathy: a functional outcome comparison study between multilevel anterior cervical decompression fusion with instrumentation and posterior laminoplasty.

BACKGROUND CONTEXT: Multilevel cervical myelopathy can be treated with anterior cervical discectomy and fusion (ACDF) or corpectomy via the anterior approach and laminoplasty via the posterior approach. Till date, there is no proven superior approach. PURPOSE: To elucidate any potential advantage of one approach over the other with regard to clinical midterm outcomes in this study. STUDY DESIGN: A prospective, 2-year follow-up of patients with cervical myelopathy treated with multilevel anterior cervical decompression fusion and plating and posterior laminoplasty. PATIENT SAMPLE: In total, 116 patients were studied. Sixty-four patients underwent ACDF two levels and above or anterior cervical corpectomy and fusion one level and above. Fifty-two patients underwent posterior cervical surgery (laminoplasty C3-C6 and C3-C7). OUTCOME MEASURES: Self-report measures: Japan Orthopedic Association (JOA) score, JOA recovery rate, visual analog scale for neck pain (VASNP), neck disability index (NDI), and American Academy of Orthopaedic Surgeons (AAOS) neurogenic symptom score (AAOS-NSS). Physiologic measures: range of motion (ROM) flexion and extension of neck. Functional measures: short-form 36 (SF-36) score comprising physical functioning, physical role function, bodily pain, general health, vitality, social role function, emotional role function, and mental health scales. METHODS: Comparison of the JOA scores, JOA recovery rates, NDI scores, SF-36 scores, VASNP, and ROM preoperatively to 2 years. Chi-square and two-sided Student t tests were used to analyze the variables. RESULTS: Posterior surgery took an hour shorter (p<.05) and had better improvement in JOA scores at early follow-up of 6 months (p=.025). Anterior surgery group had better improvement of NDI scores at early follow-up of 6 months (p=.024) and was associated with less blood loss intraoperatively compared with posterior surgery. There was no statistical difference between the two groups for JOA scores, JOA recovery rates, SF-36 quality-of-life scores, NDI, AAOS-NSS, VAS neck pain, and ROM at 2 years. Complications were higher for anterior surgery group: two hematoma postoperation, one vocal cord paresis, and one new onset C6/C7 dermatome numbness versus one dura leak in posterior surgery group. CONCLUSIONS: Our study showed that patients with multilevel disease treated with laminoplasty do well and compare favorably with patients treated with an anterior approach. Notably, posterior surgery was associated with shorter operating time, better improvement in JOA scores at 6 months, and a tendency toward lesser complications. Posterior surgery was not associated with increased neck disability and neck pain at 2 years. Anterior surgery had better NDI improvement at early follow-up. There is a need for a larger study that is prospectively randomized with long-term follow-up before we can confidently advocate one approach over the other in the management of cervical myelopathy.