Minimally invasive oblique interbody fusion for correction of iatrogenic lumbar deformity

Spinal instability may arise as a consequence of decompressive lumbar surgery. An oblique lumbar interbody fusion combined with pedicle screw fixation can provide indirect decompression on neural elements, stabilization of mobile spondylolisthesis, and restoration of segmental lordosis. Minimally invasive techniques may facilitate a shorter hospitalization and faster recovery than a traditional open revision operation. The authors describe the use of an anterior interbody fusion via an oblique retroperitoneal approach and posterior pedicle screw fixation to treat a 67-year-old woman who developed L3–4 and L4–5 unstable spondylolisthesis after a lumbar laminectomy.

The video can be found here: https://youtu.be/KWwGMIoDrmU.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients with Thoracolumbar Spine Trauma: Surgical Approaches

QUESTION

Does the choice of surgical approach (anterior, posterior, or combined anterior-posterior) improve clinical outcomes in patients with thoracic and lumbar fractures?

RECOMMENDATIONS

In the surgical treatment of patients with thoracolumbar burst fractures, physicians may use an anterior, posterior, or a combined approach as the selection of approach does not appear to impact clinical or neurological outcomes. Strength of Recommendation: Grade B With regard to radiologic outcomes in the surgical treatment of patients with thoracolumbar fractures, physicians may utilize an anterior, posterior, or combined approach because there is conflicting evidence in the comparison among approaches. Strength of Recommendation: Grade Insufficient With regard to complications in the surgical treatment of patients with thoracolumbar fractures, physicians may use an anterior, posterior, or combined approach because there is conflicting evidence in the comparison among approaches. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_11.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Prophylaxis and Treatment of Thromboembolic Events

QUESTION 1

Does routine screening for deep venous thrombosis prevent pulmonary embolism (or venous thromboembolism (VTE)-associated morbidity and mortality) in patients with thoracic and lumbar fractures?

RECOMMENDATION 1

There is insufficient evidence to recommend for or against routine screening for deep venous thrombosis in preventing pulmonary embolism (or VTE-associated morbidity and mortality) in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade Insufficient.

QUESTION 2

For patients with thoracic and lumbar fractures, is one regimen of VTE prophylaxis superior to others with respect to prevention of pulmonary embolism (or VTE-associated morbidity and mortality)?

RECOMMENDATION 2

There is insufficient evidence to recommend a specific regimen of VTE prophylaxis to prevent pulmonary embolism (or VTE-associated morbidity and mortality) in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade Insufficient.

QUESTION 3

Is there a specific treatment regimen for documented VTE that provides fewer complications than other treatments in patients with thoracic and lumbar fractures?

RECOMMENDATION 3

There is insufficient evidence to recommend for or against a specific treatment regimen for documented VTE that would provide fewer complications than other treatments in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade Insufficient.

RECOMMENDATION 4

Based on published data from pooled (cervical and thoracolumbar) spinal cord injury populations, the use of thromboprophylaxis is recommended to reduce the risk of VTE events in patients with thoracic and lumbar fractures. Consensus Statement by the Workgroup The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_7.

The atlantoaxial capsular ligaments and transverse ligament are the primary stabilizers of the atlantoaxial joint in the craniocervical junction: a finite element analysis

OBJECTIVE

Prior studies have provided conflicting evidence regarding the contribution of key ligamentous structures to atlantoaxial (AA) joint stability. Many of these studies employed cadaveric techniques that are hampered by the inherent difficulties of testing isolated-injury scenarios. Analysis with validated finite element (FE) models can overcome some of these limitations. In a previous study, the authors completed an FE analysis of 5 subject-specific craniocervical junction (CCJ) models to investigate the biomechanics of the occipitoatlantal joint and identify the ligamentous structures essential for its stability. Here, the authors use these same CCJ FE models to investigate the biomechanics of the AA joint and to identify the ligamentous structures essential for its stability.

METHODS

Five validated CCJ FE models were used to simulate isolated- and combined ligamentous–injury scenarios of the transverse ligament (TL), tectorial membrane (TM), alar ligament (AL), occipitoatlantal capsular ligament, and AA capsular ligament (AACL). All models were tested with rotational moments (flexion-extension, axial rotation, and lateral bending) and anterior translational loads (C2 constrained with anterior load applied to the occiput) to simulate physiological loading and to assess changes in the atlantodental interval (ADI), a key radiographic indicator of instability.

RESULTS

Isolated AACL injury significantly increased range of motion (ROM) under rotational moment at the AA joint for flexion, lateral bending, and axial rotation, which increased by means of 28.0% ± 10.2%, 43.2% ± 15.4%, and 159.1% ± 35.1%, respectively (p ≤ 0.05 for all). TL removal simulated under translational loads resulted in a significant increase in displacement at the AA joint by 89.3% ± 36.6% (p < 0.001), increasing the ADI from 2.7 mm to 4.5 mm. An AACL injury combined with an injury to any other ligament resulted in significant increases in ROM at the AA joint, except when combined with injuries to both the TM and the ALs. Similarly, injury to the TL combined with injury to any other CCJ ligament resulted in a significant increase in displacement at the AA joint (significantly increasing ADI) under translational loads.

CONCLUSIONS

Using FE modeling techniques, the authors showed a significant reliance of isolated- and combined ligamentous–injury scenarios on the AACLs and TL to restrain motion at the AA joint. Isolated injuries to other structures alone, including the AL and TM, did not result in significant increases in either AA joint ROM or anterior displacement.

Analysis of an overlapping surgery policy change on costs in a high-volume neurosurgical department

OBJECTIVE

Overlapping surgery remains a controversial topic in the medical community. Although numerous studies have examined the safety profile of overlapping operations, there are few data on its financial impact. The authors assessed direct hospital costs associated with neurosurgical operations during periods before and after a more stringent overlapping surgery policy was implemented.

METHODS

The authors retrospectively reviewed the records of nonemergency neurosurgical operations that took place during the periods from June 1, 2014, to October 31, 2014 (pre–policy change), and from June 1, 2016, to October 31, 2016 (post–policy change), by any of the 4 senior neurosurgeons authorized to perform overlapping cases during both periods. Cost data as well as demographic, surgical, and hospitalization-related variables were obtained from an institutional tool, the Value-Driven Outcomes database.

RESULTS

A total of 625 hospitalizations met inclusion criteria for cost analysis; of these, 362 occurred prior to the policy change and 263 occurred after the change. All costs were reported as a proportion of the average total hospitalization cost for the entire cohort. There was no significant difference in mean total hospital costs between the prechange and postchange period (0.994 ± 1.237 vs 1.009 ± 0.994, p = 0.873). On multivariate linear regression analysis, neither the policy change (p = 0.582) nor the use of overlapping surgery (p = 0.273) was significantly associated with higher total hospital costs.

CONCLUSIONS

A more restrictive overlapping surgery policy was not associated with a reduction in the direct costs of hospitalization for neurosurgical procedures.

Spine trauma and spinal cord injury in Utah: a geographic cohort study utilizing the National Inpatient Sample

OBJECTIVE

The objective of this study was to investigate the effect of hospital type and patient transfer during the treatment of patients with vertebral fracture and/or spinal cord injury (SCI).

METHODS

The National Inpatient Sample (NIS) database was queried to identify patients treated in Utah from 2001 to 2011 for vertebral column fracture and/or SCI (ICD-9-CM codes 805, 806, and 952). Variables related to patient transfer into and out of the index hospital were evaluated in relation to patient disposition, hospital length of stay, mortality, and cost.

RESULTS

A total of 53,644 patients were seen (mean [± SEM] age 55.3 ± 0.1 years, 46.0% females, 90.2% white), of which 10,620 patients were transferred from another institution rather than directly admitted. Directly admitted (vs transferred) patients showed a greater likelihood of routine disposition (54.4% vs 26.0%) and a lower likelihood of skilled nursing facility disposition (28.2% vs 49.2%) (p < 0.0001). Directly admitted patients also had a significantly shorter length of stay (5.6 ± 6.7 vs 7.8 ± 9.5 days, p < 0.0001) and lower total charges ($26,882 ± $37,348 vs $42,965 ± $52,118, p < 0.0001). A multivariable analysis showed that major operative procedures (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.4-2.0, p < 0.0001) and SCI (HR 2.1, 95% CI 1.6-2.8, p < 0.0001) were associated with reduced survival whereas patient transfer was associated with better survival rates (HR 0.4, 95% CI 0.3-0.5, p < 0.0001). A multivariable analysis of cost showed that disposition (β = 0.1), length of stay (β = 0.6), and major operative procedure (β = 0.3) (p < 0.0001) affected cost the most.

CONCLUSIONS

Overall, transferred patients had lower mortality but greater likelihood for poor outcomes, longer length of stay, and higher cost compared with directly admitted patients. These results suggest some significant benefits to transferring patients with acute injury to facilities capable of providing appropriate treatment, but also support the need to further improve coordinated care of transferred patients, including surgical treatment and rehabilitation.

The occipitoatlantal capsular ligaments are the primary stabilizers of the occipitoatlantal joint in the craniocervical junction: a finite element analysis

OBJECTIVE

There is contradictory evidence regarding the relative contribution of the key stabilizing ligaments of the occipitoatlantal (OA) joint. Cadaveric studies are limited by the nature and the number of injury scenarios that can be tested to identify OA stabilizing ligaments. Finite element (FE) analysis can overcome these limitations and provide valuable data in this area. The authors completed an FE analysis of 5 subject-specific craniocervical junction (CCJ) models to investigate the biomechanics of the OA joint and identify the ligamentous structures essential for stability.

METHODS

Isolated and combined injury scenarios were simulated under physiological loads for 5 validated CCJ FE models to assess the relative role of key ligamentous structures on OA joint stability. Each model was tested in flexion-extension, axial rotation, and lateral bending in various injury scenarios. Isolated ligamentous injury scenarios consisted of either decreasing the stiffness of the OA capsular ligaments (OACLs) or completely removing the transverse ligament (TL), tectorial membrane (TM), or alar ligaments (ALs). Combination scenarios were also evaluated.

RESULTS

An isolated OACL injury resulted in the largest percentage increase in all ranges of motion (ROMs) at the OA joint compared with the other isolated injuries. Flexion, extension, lateral bending, and axial rotation significantly increased by 12.4% ± 7.4%, 11.1% ± 10.3%, 83.6% ± 14.4%, and 81.9% ± 9.4%, respectively (p ≤ 0.05 for all). Among combination injuries, OACL+TM+TL injury resulted in the most consistent significant increases in ROM for both the OA joint and the CCJ during all loading scenarios. OACL+AL injury caused the most significant percentage increase for OA joint axial rotation.

CONCLUSIONS

These results demonstrate that the OACLs are the key stabilizing ligamentous structures of the OA joint. Injury of these primary stabilizing ligaments is necessary to cause OA instability. Isolated injuries of TL, TM, or AL are unlikely to result in appreciable instability at the OA joint.

Delayed Occipitocervical Instability With Cranial Settling After Far-Lateral Transcondylar Surgery for Invasive Skull Base Tumor

BACKGROUND

Occipitocervical instability is a rare but potentially severe complication of a far-lateral transcondylar surgical approach to the skull base.

OBJECTIVE

To investigate the incidence of clinically significant occipitocervical instability after transcondylar surgery via a far-lateral approach and to determine whether the extent of occipital condyle resection relative to the hypoglossal canal was associated with the development of occipitocervical instability.

METHODS

A retrospective review of patients undergoing far-lateral transcondylar surgery was performed at our institution to identify patients who developed postoperative occipitocervical instability.

RESULTS

Of the 61 far-lateral transcondylar operations performed, the authors identified 2 cases of delayed occipitocervical instability after surgery. In each case, the patient had tumor invading into the occipital condyle and supracondylar region and a resection extending anterior to the hypoglossal canal was performed. Both patients presented with pathological fractures and a severe occipitocervical deformity.

CONCLUSION

Patients who have tumor involvement of the occipital condyle and supracondylar region and undergo partial unilateral condylar resection are at risk for occipitocervical instability and should be considered for occipitocervical fusion.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Classification of Injury

QUESTION 1

Are there classification systems for fractures of the thoracolumbar spine that have been shown to be internally valid and reliable (ie, do these instruments provide consistent information between different care providers)?

RECOMMENDATION 1

A classification scheme that uses readily available clinical data (eg, computed tomography scans with or without magnetic resonance imaging) to convey injury morphology, such as Thoracolumbar Injury Classification and Severity Scale or the AO Spine Thoracolumbar Spine Injury Classification System, should be used to improve characterization of traumatic thoracolumbar injuries and communication among treating physicians. Strength of Recommendation: Grade B.

QUESTION 2

In treating patients with thoracolumbar fractures, does employing a formally tested classification system for treatment decision-making affect clinical outcomes?

RECOMMENDATION 2

There is insufficient evidence to recommend a universal classification system or severity score that will readily guide treatment of all injury types and thereby affect outcomes. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_2.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Radiological Evaluation

BACKGROUND

Radiological evaluation of traumatic thoracolumbar fractures is used to classify the injury and determine the optimal treatment plan. Currently, there remains a lack of consensus regarding appropriate radiological protocol. Most clinicians use a combination of plain radiographs, 3-dimensional computed tomography with reconstructions, and magnetic resonance imaging (MRI).

OBJECTIVE

To determine, through evidence-based guidelines review: (1) whether the use of MRI to identify ligamentous integrity predicted the need for surgical intervention; and (2) if there are any radiological findings that can assist in predicting clinical outcomes.

METHODS

A systematic review of the literature was performed using the National Library of Medicine/PubMed database and the Cochrane Library for studies relevant to thoracolumbar trauma. Clinical studies specifically addressing the radiological evaluation of thoracolumbar spine trauma were selected for review.

RESULTS

Two of 2278 studies met inclusion criteria for review. One retrospective review (Level III) and 1 prospective cohort (Level III) provided evidence that the addition of an MRI scan in acute thoracic and thoracolumbar trauma can predict the need for surgical intervention. There was insufficient evidence that MRI can help predict clinical outcomes in patients with acute traumatic thoracic and thoracolumbar spine injuries.

CONCLUSION

This evidence-based guideline provides a Grade B recommendation that radiological findings in patients with acute thoracic or thoracolumbar spine trauma can predict the need for surgical intervention. This evidence-based guideline provides a grade insufficient recommendation that there is insufficient evidence to determine if radiographic findings can assist in predicting clinical outcomes in patients with acute thoracic and thoracolumbar spine injuries.

QUESTION 1

Are there radiographic findings in patients with traumatic thoracolumbar fractures that can predict the need for surgical intervention?

RECOMMENDATION 1

Because MRI has been shown to influence the management of up to 25% of patients with thoracolumbar fractures, providers may use MRI to assess posterior ligamentous complex integrity, when determining the need for surgery. Strength of Recommendation: Grade B.

QUESTION 2

Are there radiographic findings in patients with traumatic thoracolumbar fractures that can assist in predicting clinical outcomes?

RECOMMENDATION 2

Due to a paucity of published studies, there is insufficient evidence that radiographic findings can be used as predictors of clinical outcomes in thoracolumbar fractures. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_3.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Nonoperative Care

BACKGROUND

Thoracic and lumbar burst fractures in neurologically intact patients are considered to be inherently stable, and responsive to nonsurgical management. There is a lack of consensus regarding the optimal conservative treatment modality. The question remains whether external bracing is necessary vs mobilization without a brace after these injuries.

OBJECTIVE

To determine if the use of external bracing improves outcomes compared to no brace for neurologically intact patients with thoracic or lumbar burst fractures.

METHODS

A systematic review of the literature was performed using the National Library of Medicine PubMed database and the Cochrane Library for studies relevant to thoracolumbar trauma. Clinical studies specifically comparing external bracing to no brace for neurologically intact patients with thoracic or lumbar burst fractures were selected for review.

RESULTS

Three studies out of 1137 met inclusion criteria for review. One randomized controlled trial (level I) and an additional randomized controlled pilot study (level II) provided evidence that both external bracing and no brace equally improve pain and disability in neurologically intact patients with burst fractures. There was no difference in final clinical and radiographic outcomes between patients treated with an external brace vs no brace. One additional level IV retrospective study demonstrated equivalent clinical outcomes for external bracing vs no brace.

CONCLUSION

This evidence-based guideline provides a grade B recommendation that management either with or without an external brace is an option given equivalent improvement in outcomes for neurologically intact patients with thoracic and lumbar burst fractures. The decision to use an external brace is at the discretion of the treating physician, as bracing is not associated with increased adverse events compared to no brace.

QUESTION

Does the use of external bracing improve outcomes in the nonoperative treatment of neurologically intact patients with thoracic and lumbar burst fractures?

RECOMMENDATION

The decision to use an external brace is at the discretion of the treating physician, as the nonoperative management of neurologically intact patients with thoracic and lumbar burst fractures either with or without an external brace produces equivalent improvement in outcomes. Bracing is not associated with increased adverse events compared to not bracing. Strength of Recommendation: Grade B The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_8.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients with Thoracolumbar Spine Trauma: Operative Versus Nonoperative Treatment

QUESTION 1

Does the surgical treatment of burst fractures of the thoracic and lumbar spine improve clinical outcomes compared to nonoperative treatment?

RECOMMENDATION 1

There is conflicting evidence to recommend for or against the use of surgical intervention to improve clinical outcomes in patients with thoracolumbar burst fracture who are neurologically intact. Therefore, it is recommended that the discretion of the treating provider be used to determine if the presenting thoracic or lumbar burst fracture in the neurologically intact patient warrants surgical intervention. Strength of Recommendation: Grade Insufficient.

QUESTION 2

Does the surgical treatment of nonburst fractures of the thoracic and lumbar spine improve clinical outcomes compared to nonoperative treatment?

RECOMMENDATION 2

There is insufficient evidence to recommend for or against the use of surgical intervention for nonburst thoracic or lumbar fractures. It is recommended that the decision to pursue surgery for such fractures be at the discretion of the treating physician. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_1.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Neurological Assessment

QUESTION 1

Which neurological assessment tools have demonstrated internal reliability and validity in the management of patients with thoracic and lumbar fractures (ie, do these instruments provide consistent information between different care providers)?

RECOMMENDATION 1

Numerous neurologic assessment scales (Functional Independence Measure, Sunnybrook Cord Injury Scale and Frankel Scale for Spinal Cord Injury) have demonstrated internal reliability and validity in the management of patients with thoracic and lumbar fractures. Unfortunately, other contemporaneous measurement scales (ie, American Spinal Cord Injury Association Impairment Scale) have not been specifically studied in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade C.

QUESTION 2

Are there any clinical findings (eg, presenting neurological grade/function) in patients with thoracic and lumbar fractures that can assist in predicting clinical outcomes?

RECOMMENDATION 2

Entry American Spinal Injury Association Impairment Scale grade, sacral sensation, ankle spasticity, urethral and rectal sphincter function, and AbH motor function can be used to predict neurological function and outcome in patients with thoracic and lumbar fractures (Table I https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_4_table1). Strength of Recommendation: Grade B The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_4.

Impact of a more restrictive overlapping surgery policy: an analysis of pre- and postimplementation complication rates, resident involvement, and surgical wait times at a high-volume neurosurgical department

OBJECTIVE

Recently, overlapping surgery has been a source of controversy both in the popular press and within the academic medical community. There have been no studies examining the possible effects of more stringent overlapping surgery restrictions. At the authors’ institution, a new policy was implemented that restricts attending surgeons from starting a second case until all critical portions of the first case that could require the attending surgeon’s involvement are completed. The authors examined the impact of this policy on complication rates, neurosurgical resident education, and wait times for neurosurgical procedures.

METHODS

The authors performed a retrospective chart review of nonemergency neurosurgical procedures performed over two periods—from June 1, 2014, to October 31, 2014 (pre–policy change) and from June 1, 2016, to October 31, 2016 (post–policy change)—by any of 4 senior neurosurgeons at a single institution who were authorized to schedule overlapping cases. Information on preoperative evaluation, patient demographics, premorbid conditions, surgical variables, and postoperative course were collected and analyzed.

RESULTS

Six hundred fifty-three patients met inclusion criteria for complications analysis. Of these, 378 (57.9%) underwent surgery before the policy change. On multivariable regression analysis, neither overlapping surgery (odds ratio [OR] 1.072, 95% confidence interval [CI] 0.710–1.620) nor the overlapping surgery policy change (OR 1.057, 95% CI 0.700–1.596) was associated with overall complication rates. Similarly, neither overlapping surgery (OR 1.472, 95% CI 0.883–2.454) nor the overlapping surgery policy change (OR 1.251, 95% CI 0.748–2.091) was associated with numbers of serious complications. After the policy change, the percentage of procedures in which the senior assistant was a postresidency fellow increased significantly, from 11.9% to 34.2% (p < 0.001). In a multiple linear regression analysis of surgery wait times, patients undergoing surgery after the policy change had significantly longer delays from the decision to operate until the actual neurosurgical procedure (p < 0.001).

CONCLUSIONS

At the authors’ institution, further restriction of overlapping surgery was not associated with a reduction in overall or serious complications. Resident involvement in neurosurgical procedures decreased significantly after the policy change, and this study suggests that wait times for neurosurgical procedures also significantly lengthened.