Anterior approach to cervical spine

Effect of Furosemide on Prevertebral Soft Tissue Swelling after Anterior Cervical Fusion: A Comparative Study with Dexamethasone

STUDY DESIGN

Retrospective cohort study.

PURPOSE

This study aimed to investigate the effect of furosemide on prevertebral soft tissue swelling (PSTS) after anterior cervical fusion (ACF) and compare it with the effect of dexamethasone.

OVERVIEW OF LITERATURE

Postoperative PSTS is a common complication of ACF. Dexamethasone has been used for its treatment; however, its efficacy remains controversial. Furosemide may reduce PSTS if it is soft tissue edema; however, no studies have demonstrated the effect of furosemide on PSTS after ACF.

METHODS

The symptomatic PSTS group received intravenous (IV) administration of dexamethasone or furosemide. The asymptomatic PSTS group did not receive any medication. Patients were divided into the control (no medication, n=31), Dexa (IV dexamethasone, n=25), and Furo (IV furosemide, n=28) groups. PSTS was checked daily with simple radiographs and medication-induced reductions in PSTS from its peak or after medication.

RESULTS

The peak time (postoperative days) of PSTS in the control (2.27±0.47, p<0.05) and Dexa (1.91±0.54, p<0.01) groups were significantly later than that in the Furo group (1.38±0.74). PSTS was significantly lower in the Furo group than in the Dexa group from postoperative days 4 to 7 (p<0.05). PSTS reduction after the peak was significantly greater in the Furo group than in the control (p<0.01) and Dexa (p<0.01) groups. After starting the medication therapy, the Furo group showed a significantly greater reduction in PSTS than the Dexa group (p<0.01). No difference was found in symptom improvement among the three groups.

CONCLUSIONS

If furosemide is used to reduce PSTS after ACF, it can effectively reduce symptoms.

[Translated article] Vertebral metastases. En bloc treatment

En bloc resection of vertebral metastases has been the subject of study in medical literature due to its impact on patients' quality of life and effectiveness in local disease control. This bibliographic analysis examines the findings and perspectives of published studies concerning en bloc resection of oligometastases in the spine. The technique, which involves the complete removal of the tumour along with a portion of the surrounding bone, has been shown to improve local tumour control, reduce recurrence, and potentially prolong patient survival compared to conventional decompression and stabilisation techniques. However, en bloc resection also presents risks and complications, such as surgical morbidity and extended recovery time. Appropriate patient selection, preoperative planning, and a multidisciplinary approach are essential to optimise outcomes. As new techniques and advances in adjuvant treatment develop, en bloc resection of oligometastases in the spine remains an area of interest in oncological research.

Vertebral metastases. En bloc treatment

En bloc resection of vertebral metastases has been the subject of study in medical literature due to its impact on patients' quality of life and effectiveness in local disease control. This bibliographic analysis examines the findings and perspectives of published studies concerning en bloc resection of oligometastases in the spine. The technique, which involves the complete removal of the tumour along with a portion of the surrounding bone, has been shown to improve local tumour control, reduce recurrence, and potentially prolong patient survival compared to conventional decompression and stabilization techniques. However, en bloc resection also presents risks and complications, such as surgical morbidity and extended recovery time. Appropriate patient selection, preoperative planning, and a multidisciplinary approach are essential to optimize outcomes. As new techniques and advances in adjuvant treatment develop, en bloc resection of oligometastases in the spine remains an area of interest in oncological research.

Anterior Fusion and Long-Term Cervical Mobility in Patients With Traumatic Spinal Cord Injury: An Observational Study

Objective This study aims to determine and quantify the impairment of cervical mobility and range of motion in patients with traumatic spinal cord injury (SCI) and subsequent cervical subaxial fusion surgery. Methods A total of 89 patients who underwent interbody fusion of the cervical spine and were admitted to the Spinal Cord Injury Center of the BG Klinikum Hamburg, Germany between 2003 and 2018 were examined after their in-facility rehabilitation was successfully completed. Reclination, inclination, tilt, and rotation of the cervical spine were examined and documented in addition to overall patient characteristics and fusion extent. Results We could identify fusion length and age to be independently negatively correlated with the cervical range of motion in different degrees of movement. We could also show a significant decrease in cervical mobility within our patients when compared to healthy adults. The ability to tilt and rotate the cervical spine was particularly impaired. Conclusions Patients with traumatic SCI and intervertebral fusion suffer from significant impairment of mobility in different degrees of movement. This knowledge can be used to evaluate the rehabilitative challenges and reintegrative needs of individuals after traumatic SCI. Rehabilitation should be adjusted accordingly.

Identification of Deep Cervical Fascial Layers During Anterior Cervical Spine Exposure

BACKGROUND

Anterior approaches to the cervical spine are among the most common exposures by which neurosurgeons and orthopedic surgeons access the prevertebral space and ultimately the cervical disk and vertebral bodies. There is a paucity of literature describing the microanatomic fascial planes of the neck with respect to anterior cervical approaches.

OBJECTIVE

To delineate the microanatomic connections of the cervical fascial planes pertinent to anterior cervical exposure.

METHODS

Using a cadaveric model, original illustrations, the Visible Human Project, and an original surgical video, we demonstrate a stepwise method for identifying the correct planes for anterior cervical exposure.

RESULTS

A step-by-step method for identifying the anterior cervical fascial planes intraoperatively is demonstrated.

CONCLUSION

A comprehensive understanding of anterior cervical microsurgical anatomy is vital for performing a methodical yet efficient approach to the prevertebral space while minimizing retraction and iatrogenic injury to the surrounding neurovascular structures.

Holistic Approach to the Diagnosis and Treatment of Patients with Tumor Metastases to the Spine

The treatment of neoplastic spine metastases requires multi-faceted assessment and an interdisciplinary approach to patients. The metastases do not show specific symptoms but are often the first confirmation of the presence of a primary tumor in a patient. The diagnostic process includes imaging and invasive procedures, e.g., biopsy. It is essential to qualify the patient for an appropriate treatment using dedicated scales. Decompression of the spinal cord is a critical issue to save or restore neurological function in a patient with spine metastases. Surgical treatment ought to meet three criteria: release spinal cord and nerve roots, restore the spine’s anatomical relations, and ensure the internal stabilization of the spine. A good result from surgical treatment enables the continuation of radiotherapy, chemotherapy, hormone therapy, and targeted molecular therapy. Stereotactic radiosurgery and stereotactic body radiotherapy are more effective ways of treating spine metastases than conventional external beam radiotherapy. They allow higher doses of radiation, concentrated precisely at the tumor site. Our review summarizes the established and emerging concepts in the treatment of spine metastases. A holistic approach to the patient enables the selection of the appropriate therapy.

Transnasal Endoscopic and Transoral Approaches in the Biopsies of Ventral Atlas and Axis Vertebrae: A Comprehensive Retrospective Study for Preprocedural Scheme, Biopsy Procedure, Core Technique Analysis, Diagnostic Yield and Clinical Outcome

OBJECTIVE

This study aims to describe and analyze the transoral and transnasal approaches for pathologies of the ventral atlas and axis vertebrae, which are considered technically challenging regions for diagnostic biopsy.

METHODS

A series of transnasal endoscopic approach (TNA) and transoral approach (TOA) biopsies for the pathologies of the first and second cervical vertebrae were conducted and retrospectively analyzed from July 2014 to May 2021. The depth of the biopsy trajectory was measured on computed tomography images for all nine patients (eight males and one female with an average age of 58.11 ± 11.60 years), as were the coronal, sagittal, and vertical biopsy safe ranges. The characteristics of each lesion, including radiographic features, blood supply, and destruction of anterior or posterior vertebral body edges, were evaluated to guide the biopsy. Four biopsy core techniques (BCTs), including "lesion perforating", "aspiration", "cutting-and-scraping" and "biopsy forceps utilization" were elaborated in this study. The biopsy procedures and periprocedural precautions were demonstrated. Patient demographics, clinical data, lesion characteristics, diagnostic yield, and complications were recorded for each case.

RESULTS

Eight TOA biopsies for the axis vertebral body and one TNA biopsy for the atlas anterior arch were successfully performed and yielded adequate pathologies. All biopsies were organized based on the preprocedural radiographic measurements, which showed that the average length of biopsy trajectory and coronal, sagittal, and vertical safe biopsy ranges were 85.00 ± 5.88, 20.63 ± 4.75, 16.25 ± 1.49, and 24.63 ± 2.26 mm, respectively, and these corresponding data were 95, 36, 9, and 26 mm in the TNA patient. Six osteolytic lesions (66.7%), one osteoblastic lesion (11.1%), and two mixed lesions (22.2%) were observed, among which seven lesions had a rich blood supply. Biopsy forceps and core needles were utilized to obtain samples in six and three patients, respectively. All the TNA and TOA biopsies were performed with cooperative application of multiple BCTs under compound anatomic and stereotactic navigations. Intraprocedural or postprocedural complications occurred in no patients who underwent the biopsy in the follow-up period (1-39 months). No significant differences were found between the preprocedural and postprocedural blood indexes and visual analogue scale scores.

CONCLUSION

With a sophisticated preprocedural arrangement, cooperative application of BCTs, and careful periprocedural precautions, transnasal endoscopic and transoral biopsies are two feasible, efficient, and well-tolerated procedures that achieve satisfactory diagnostic yield, complication rate, and clinical outcome.

The adjustable aiming device for caspar pin insertion in anterior cervical spine surgery

BACKGROUND

Creating a rectangular disc space is an important step during anterior cervical discectomy and fusion or cervical total disc replacement. The study aims to determine the accuracy of Caspar pin insertion by using a novel Adjustable Caspar Pin Aiming Device in anterior cervical procedures.

METHODS

Forty Caspar pins were placed using an Adjustable Caspar Pin Aiming Device in 20 human cadaveric cervical vertebral bodies from C3 to C7 after performing anterior discectomies. Accuracy of pin placement was assessed by lateral fluoroscopy, considering superior endplate slope (SE), inferior endplate slope (IE), Caspar pin slope (CP), and endplate-Caspar pin slope difference (SE/CP, IE/CP).

RESULTS

The mean superior endplate slope (SE), inferior endplate slope (IE), and Caspar pin slope (CP) were 10.82 ± 2.3°, 10.32 ± 3.2°, and 15.58 ± 7.9°, respectively. The average superior endplate-Caspar pin slope difference (SE/CP) and inferior endplate-Caspar pin slope difference (IE/CP) were 6.6 ± 0.8° and 7.7 ± 0.8°, respectively. The greatest slope difference was observed at the superior and inferior endplates of C3. No cervical endplate violations occurred.

CONCLUSION

Adjustable Caspar Pin Aiming Device allowed for a highly accurate Caspar pin placement with the average endplate-Caspar pin slope difference of less than 7.7°. It results in accurate placement of the superior and inferior Caspar pins parallel to the index vertebral endplates. Furthermore, it appears to facilitate the safe and effective insertion of Caspar pins for anterior cervical procedures.

Early Major Complications After Radical Resection of Primary C2-Involved Upper Cervical Chordoma Through the Combined Anterior Retropharyngeal-Posterior Approach: Incidence and Risk Factors

BACKGROUND

We investigated the frequency of postoperative major complications, length of stay (LOS), and associated risk factors for primary C2-involved upper cervical chordoma through the combined anterior retropharyngeal-posterior approach.

METHODS

Clinical data were collected from 102 patients with primary C2-involved upper cervical chordoma treated at our institute from January 2016 to January 2021. Additionally, the Changzheng Hospital (CZH) surgical classification system was designed to describe the different anatomic types of C2 chordomas. A multivariate logistic regression analysis was performed and a multivariate Cox proportional hazards model was used to identify the risk factors associated with the occurrence of major complications and prolonged length of stay (LOS), respectively.

RESULTS

The incidence of major complication was 29.41% (30 of 102) in our cohort. A long surgical duration (P = 0.001), increased age (P = 0.001), more preoperative comorbidities (P = 0.008) and CZH types indicating extensive tumor involvement (P < 0.001) were identified as significant predictors of the occurrence of a major complication postoperatively. The mean LOS for the entire study population was 21.50 ± 0.64 days. The patients who experienced complications required a significant longer LOS (25.50 ± 1.26 days) than those without complications (19.83 ± 0.65; P < 0.001). The independent factors affecting LOS included age (P = 0.001), Frankel grade (P = 0.001), CZH classification (P < 0.001), and surgical duration (P = 0.001).

CONCLUSIONS

Patients who are older, experience longer operative duration, or have larger tumor extension have a greater risk of postoperative major complication. The LOS can be predicted by age, preoperative neurological deficit, CZH classification, surgical approach, and surgical duration. Accordingly, patients with these risk factors should be monitored and targeted with preventative measures.

The aiming device for cervical distractor pin insertion: a proof-of-concept, feasibility study

Background

Restoration of cervical lordosis after anterior discectomy and fusion is a desirable goal. Proper insertion of the vertebral distraction or Caspar pin can assist lordotic restoration by either putting the tips divergently or parallel to the index vertebral endplates. With inexperienced surgeons, the traditional free-hand technique for Caspar pin insertion may require multiple insertion attempts that may compromise the vertebral body and increase radiation exposure during pin localization. Our purpose is to perform a proof-of-concept, feasibility study to evaluate the effectiveness of a pin insertion aiming device for vertebral distraction pin insertion.

Methods

A Smith-Robinson approach and anterior cervical discectomy were performed from C3 to C7 in 10 human cadaveric specimens. Caspar pins were inserted using a novel pin insertion aiming device at C3-4, C4-5, C5-6, and C6-7. The angles between the cervical endplate slope and Caspar pin alignment were measured with lateral cervical imaging.

Results

The average Superior Endplate-to-Caspar Pin angle (SE-CP) and the average Inferior Endplate-to-Caspar Pin angle (IE-CP) were 6.2 ± 2.0° and 6.3 ± 2.2° respectively. For the proximal pins, the SE-CP and the IE-CP were 4.0 ± 1.1°and 5.2 ± 2.4° respectively. For the distal pins, the SE-CP and the IE-CP were 7.7 ± 1.4° and 6.2 ± 2.0° respectively. No cervical endplate violations occurred.

Conclusion

The novel Caspar pin insertion aiming device can control the pin entry points and pin direction with the average SE-CP and average IE-CP of 6.2 ± 2.0° and 6.3 ± 2.2°, respectively. The study shows that the average different angles between the Caspar pin and cervical endplate are less than 7°.

National Trends and Correlates of Dysphagia After Anterior Cervical Discectomy and Fusion Surgery

Objective

Anterior cervical discectomy and fusion (ACDF) is the most common performed surgery in the cervical spine. Dysphagia is one of the most frequent complications following ACDF. Several studies have identified certain demographic and perioperative risk factors associated with increased dysphagia rates, but few have reported recent trends. Our study aims to report current trends and factors associated with the development of inpatient postoperative dysphagia after ACDF.

Methods

The National Inpatient Sample was evaluated from 2004 to 2014 and discharges with International Classification of Diseases procedure codes indicating ACDF were selected. Time trend series plots were created for the yearly treatment trends for each fusion level by dysphagia outcome. Separate univariable followed by multivariable logistic regression analyses were performed to evaluate predictors of dysphagia.

Results

A total of 1,212,475 ACDFs were identified in which 3.3% experienced postoperative dysphagia. A significant increase in annual dysphagia rates was observed from 2004–2014. Frailty, intraoperative neuromonitoring, 4 or more level fusions, African American race, fluid/electrolyte disorders, blood loss, and coagulopathy were all identified as significant independent risk factors for the development of postoperative dysphagia following ACDF.

Conclusion

Postoperative dysphagia is a well-known postsurgical complication associated with ACDF. Our cohort showed a significant increase in the annual dysphagia rates independent of levels fused. We identified several risk factors associated with the development of postoperative dysphagia after ACDF.

Anterior Approach to the Subaxial Cervical Spine: Pearls and Pitfalls

Since its introduction by Smith and Robinson, the anterior approach to the subaxial cervical spine has become one of the standard procedures for numerous cervical spine pathologies, including, but not limited to degenerative disease, trauma, tumor, deformity, and instability. Along with its increasing popularity and improvements in anterior instrumentation techniques, a comprehensive knowledge of the surgical anatomy during the anterior exposure is critical for trainees and experienced spine surgeons alike to minimize the infrequent but potentially devastating risks associated with this approach. Understanding the anatomy and techniques to minimize damage to relevant structures can reduce the risks of developing notable postoperative complications and morbidity.

Comparison of Patient-Reported Postoperative Dysphagia in Patients Undergoing One-Level Versus Two-Level Anterior Cervical Discectomy and Fusion with the Zero-P Implant System

To investigate whether dysphagia differs between one-level and two-level anterior cervical discectomy and fusion (ACDF) with the Zero Profile (Zero-P) Implant System. A retrospective analysis of 208 patients who underwent ACDF with the Zero-P Implant System and had at least one year of follow-up was performed from January 2013 to December 2018. The patients were divided into two groups based on the number of operated levels (one-level group, N = 86; two-level group, N = 122). Dysphagia was assessed based on the Bazaz grading system. The incidence of dysphagia and the severity of dysphagia at each follow-up were compared between the two groups. The patients were divided into two groups (nondysphagia group, N = 160; dysphagia group, N = 48), and covariates were obtained for multivariate analysis, including demographic parameters, surgical parameters, and radiographic parameters. The results showed that the incidence and severity of postoperative dysphagia in the two-level group were significantly greater at 1 week, 1 month and 3 months postoperatively than those in the one-level group. The results of ordinal logistic regression showed that older age, two-level surgery, greater prevertebral soft tissue swelling (PSTS) and the difference between the postoperative and preoperative C_2-7 angle (dC_2-7A) were significantly associated with a higher incidence of dysphagia after ACDF with the Zero-P. Two-level ACDF with the Zero-P can result in a significantly greater incidence and severity of transient postoperative dysphagia. Older age, greater PSTS and the dC_2-7A were also associated with postoperative dysphagia after ACDF with the Zero-P.

The Smith-Robinson Approach to the Subaxial Cervical Spine: A Stepwise Microsurgical Technique Using Volumetric Models From Anatomic Dissections

BACKGROUND

The Smith-Robinson1 approach (SRA) is the most widely used route to access the anterior cervical spine. Although several authors have described this approach, there is a lack of the stepwise anatomic description of this operative technique. With the advent of new technologies in neuroanatomy education, such as volumetric models (VMs), the understanding of the spatial relation of the different neurovascular structures can be simplified.

OBJECTIVE

To describe the anatomy of the SRA through the creation of VMs of anatomic dissections.

METHODS

A total of 4 postmortem heads and a cervical replica were used to perform and record the SRA approach to the C4-C5 level. The most relevant steps and anatomy of the SRA were recorded using photogrammetry to construct VM.

RESULTS

The SRA was divided into 6 major steps: positioning, incision of the skin, platysma, and muscle dissection with and without submandibular gland eversion and after microdiscectomy with cage positioning. Anatomic model of the cervical spine and anterior neck multilayer dissection was also integrated to improve the spatial relation of the different structures.

CONCLUSION

In this study, we review the different steps of the classic SRA and its variations to different cervical levels. The VMs presented allow clear visualization of the 360-degree anatomy of this approach. This new way of representing surgical anatomy can be valuable resources for education and surgical planning.

Anatomic and radiologic relationships of neck structures to cervical spine: implications for anterior surgical approaches

The position of the pharyngolaryngeal framework is very important in choosing the best surgical approach for cervical spine disease. The aim of the present paper is to investigate the position of the hyoid bone and cricoid cartilage in relation to the cervical spine. Moreover, the surgical implications for anterior transcervical approaches to the upper spine and the prevertebral space are discussed. To minimise complication rates and increase surgical effectiveness, the location and extent of the cervical spine disease should be evaluated in the context of the patient’s specific anatomy. A retrospective analysis of 100 cervical spine MRIs was conducted. Patients with diseases that could alter anatomic relationships of cervical structures were excluded. The mid-sagittal view of the hyoid and the inferior margin of the cricoid cartilage were projected perpendicularly to the anterior surface of the cervical vertebrae. The distance between these two landmarks was measured on the same view. The distribution of hyoid projections ranged between C2-C3 and C4-C5 intervertebral space, while the cricoid cartilage ranged between C4-C5 and C7-T1 intervertebral spaces. The mean distance between these two landmarks was 49.1 ± 7.7 mm, with statistically significant differences between males and females. The position of the cricoid cartilage significantly influenced the length of the pharyngolaryngeal framework, while the position of hyoid did not. A wide range of variability in the position of the hyoid bone and the cricoid cartilage in relation to cervical levels exists. This implies that an a priori association of a cervical level to neck structures at risk might be inaccurate. The use of these easily identifiable landmarks on pre-operative imaging may help to guide the choice among different anterior surgical approaches to cervical spine and reduce the risk of surgical complications.

Klippel–Feil Syndrome with Multiple Cervical Anomalies Discovered Following Trauma

The approach to the upper cervical spine is a challenge for surgeons, not only for its complex anatomy but also for the great variety of pathologies. Klippel–Feil syndrome (KFS) is a congenital disease characterized by the fusion of two or more cervical segments and is associated with various musculoskeletal and vascular malformations. However, there is no consensus on the type of surgery, approach, level of fixation or fusion. We report the case of a KFS, associated with multiple anatomical variants, who suffered a traumatic cervical injury and underwent surgical treatment.

The effect of the difference in C2-7 angle on the occurrence of dysphagia after anterior cervical discectomy and fusion with the zero-P implant system

OBJECTIVES

To investigate the effect of the difference in C2-7 angle on dysphagia after anterior cervical discectomy and fusion (ACDF) with the Zero-P Implant System.

METHODS

A retrospective analysis of 181 patients who underwent ACDF with the Zero-P Implant System and had at least one year of follow-up from January 2011 to November 2018 was performed. All patients were divided into a non-dysphagia group and a dysphagia group to explore the effect of the difference between postoperative and preoperative C2-7 angle (dC2-7A) on postoperative dysphagia. At the same time, other possible related factors including the difference between postoperative and preoperative O-C2 angle (dO-C2A), sex, age, body mass index (BMI), intraoperative time, estimated blood loss, diabetes mellitus, hypertension, smoking, alcohol consumption, prevertebral soft-tissue swelling (PSTS), the highest segment involved in the surgery and the levels of surgery segments were analyzed.

RESULTS

In total, the non-dysphagia group comprised 139 patients and the dysphagia group comprised 42 patients. The single-factor analysis showed that smoking, PSTS and dC2-7A were significantly different between the two groups (P < 0.05). Spearman's correlation coefficient showed no significant correlation between the degree of dysphagia and dC2-7A (P > 0.05). The results of the multiple-factor analysis with an ordinal logistic regression model showed that smoking, PSTS and dC2-7A were significantly associated with the incidence of dysphagia (P < 0.05).

CONCLUSIONS

The postoperative C2-7 angle has an important effect on the occurrence of dysphagia in patients undergoing Zero-P implant system interbody fusion surgery.

Irreversible Hypoglossal Nerve Injury and Concomitant Trigeminal System Dysfunction After Anterior Surgery to the Cervical Spine: Case Report and Literature Review

BACKGROUND

The anterior surgical approach to the cervical spine is known to be safe, and damage to the hypoglossal nerve and trigeminal pathway after the surgery is uncommon. However, once damage to those nerves occurs, the patient's quality of life can be severely impaired by discomfort and disability.

CASE DESCRIPTION

We report the case of a 59-year-old male with concomitant and irreversible hypoglossal nerve and trigeminal system dysfunction after cervical spine surgery by the anterior approach confirmed by an electrodiagnostic study. He had undergone anterior cervical disc fusion through right-sided approach for a herniated intervertebral disc on the C3-4 level and direct cord compression. He had difficulty with tongue movement, dysarthria, and hypesthesia along the lower margin of the right mandible immediately after the surgery. An electrodiagnostic study revealed hypoglossal neuropathy and trigeminal somatosensory pathway dysfunction. Even though the patient received rehabilitation therapy for impaired tongue movement for more than 2 years, this function did not recover.

CONCLUSIONS

It is important to be aware of the complexity of the anatomy of vulnerable structures, including hypoglossal nerves and the trigeminal nerve system at the cervical spine level, to prevent damage to important neural structures during surgical procedures.

Feasibility of Sub-Axial Cervical Laminar Screws, Including C7, in the Indian Population: A Study on 50 Patients Using Computed Tomography-Based Morphometry Measurements

STUDY DESIGN

Observational study of computed tomography (CT) data.

PURPOSE

We performed a CT-based radiographic analysis of sub-axial cervical lamina in the Indian population to assess the feasibility of laminar screws.

OVERVIEW OF LITERATURE

Morphometric studies have been performed for populations of various ethnic groups, but none exist for Indian populations.

METHODS

Cervical spine CT scans of 50 adults with a minimum slice thickness of <2 mm (0.5-2 mm) were obtained from the database of a single center in northern India. Measurements (e.g., length, thickness, and height) were taken in millimeters along the axial, coronal, and sagittal planes. Three measurements were made to assess laminar anatomy, namely, the translaminar/screw length, laminar thickness, and sagittal laminar height.

RESULTS

The final sample comprised 500 laminae in 50 patients, resulting in 1,500 measurements. The mean translaminar lengths of the C3, C4, C5, C6, and C7 laminae were 19.48 mm, 19.60 mm, 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- , 19.60 , 19.60 mm, 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- mm, 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- , 19.61 , 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- , 20.49 , 20.49 mm, and 22.85 mm, respectively. The mean thick- mm, and 22.85 mm, respectively. The mean thick- , and 22.85 mm, respectively. The mean thick , and 22.85 mm, respectively. The mean thicknesses of these cervical laminae were 3.12 mm, 2.62 mm, 2.56 mm, 3.47 mm, and 5.20 mm, respectively. The mean sagittal heights of these laminae were 9.38 mm, 9.80 mm, 10.12 mm, 11.31 mm, and 13.84 mm, respectively. Except for the C7 vertebrae, all other levels had a success rate of <10% in the Indian population using the criteria of a laminar height of at least 9 mm and thickness of 4.5 mm. Limited success was achieved at the C5, C6, and C3 levels.

CONCLUSIONS

To the best of our knowledge, the present study is the only series on the feasibility of laminar screws in the sub-axial cervical spine in the Indian population. We found that Indian patients have smaller anatomical dimensions and thus, are not suitable for laminar screws in the sub-axial cervical spine, barring C7, which is contrary to findings for populations in western and south Asian countries.

Craniovertebral Junction Transoral Approach: Predictive Factors of Complications

BACKGROUND

The transoral approach provides the most direct exposure to extradural lesions of the ventral craniovertebral junction. The morbidity and mortality from this approach greatly limits its use because they are still feared and debated. Using univariable and multivariable logistic regression analyses, this study aims to identify the factors associated with short-term complications in patients undergoing the transoral approach.

METHODS

A consecutive cohort analysis of prospectively collected data in several neurosurgery spine departments evaluated 143 consecutive patients who had undergone craniovertebral junction transoral approach surgery. The mean age at the time of surgery was 45.1 ± 19.1 years. The study analyzed the comorbidities, the operative procedure, and postoperative morbidity and mortality.

RESULTS

Seventeen patients (11.9%) had a postoperative complication in the first month. In our univariable analysis: age, smoking, tumor etiology, preoperative posterior fixation, posterior bone graft, preoperative external lumbar shunt, and the transoral approach pathway were significantly associated with postoperative mortality and morbidity. In our multivariable analyses, preoperative external lumbar shunt was significantly associated with complication risks (odds ratio [OR] 6.7; 95% confidence interval [CI] 2.1-21.7, P < 0.001), whereas preoperative posterior fixation (OR 0.28; 95% CI 0.08-1.1, P < 0.04) and posterior bone graft (OR 0.14; 95% CI 0.03-0.6, P < 0.008) were significantly associated with lower complication risks.

CONCLUSIONS

To reduce complications, it is essential to be aware of and to manage these preoperative risk factors. In such manner, we insinuate that postoperative complications depend on the surgeon's familiarity with the transoral approach.

Iatrogenic Vertebral Artery Injury During Anterior Cervical Spine Surgery: A Systematic Review

BACKGROUND

Iatrogenic vertebral artery injury (VAI) during anterior cervical surgery is rare but potentially catastrophic.

METHODS

Causes, presentation, diagnosis, management, prognosis, and prevention of VAI were reviewed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. English language studies and case reports published from 1980 to 2017 were retrieved. Data on diagnosis, surgical procedures and approach, site and cause of VAI, management, outcomes, and vertebral artery (VA) status were extracted.

RESULTS

In 25 articles including 54 patients, VAI was diagnosed during or after surgery commonly indicated for cervical degenerative diseases (64%), tumors (14%), and trauma (9%). The incidence of VAI for each side was similar regardless of approach. Common presentations were unexpected copious surgical bleeding, delayed hemorrhage of pseudoaneurysm with neck swelling, dyspnea, hypotension, and cervical bruits caused by arteriovenous fistula. Causes included drilling (61%), instrumentation (16%), and soft tissue retraction (8%). Direct exposure or angiography confirmed VAI. Ten patients had VA anomalies; collateral status was verified in 9 before definitive treatment. Tamponade was adopted for urgent hemostasis in most cases but with a high incidence of pseudoaneurysm (48%). Unknown VA status increased occlusion risk and neurologic sequelae (41%). VA repair and stent placement had excellent outcomes.

CONCLUSIONS

Extensive lateral decompression, loss of landmarks, and anatomic variations or pathologic status of VA increased VAI risk. Evaluation of collateral vessels before definitive treatment helped determine appropriate management and avoid neurologic sequelae. Tamponade was not recommended as definitive treatment. Meticulous preoperative evaluation, cautious intraoperative manipulation, and real-time radiographic guidance reduced VAI risk.

Lower cervical levels: Increased risk of early dysphonia following anterior cervical spine surgery

OBJECTIVES

The present study aimed to re-evaluate the incidence of early dysphonia after anterior cervical spine surgery (ACSS) and to determine the related risk factors.

CLINICAL MATERIALS AND METHODS

Patients underwent ACSS between January 2011 and December 2013 at two sites were identified retrospectively from hospital's patient databases. A total of 233 cases were included in this study. Dysphonia developed 1 month postoperatively was recorded. Follow-up was conducted in all positive-response patients. Those reporting severe or persistent voice symptoms were referred to otolaryngologists for further assessments and (or) treatments. Pre and intraoperative factors were collected to determine their relationships with dysphonia one month postoperatively.

RESULTS

45 patients developed dysphonia at one month, including 23 males and 22 females, yielding to an incidence of 19.3%. 34 cases resolved themselves in 3 months, leaving the remaining 11 patients considered to be severe or persistent cases. However, 10 of them recovered spontaneously in the next 9 months, while the last case received vocal cord medialization and returned to almost normal speech function at 18 months. In univariate analysis, only approaching level involving C6-C7 or (and) C7-T1 was significantly associated with postoperative dysphonia (P<0.001). This association was not weakened in multiple logistic regression analysis (OR 2.348, 95% CI 1.467-3.659, P<0.001).

CONCLUSION

The incidence of early dysphonia following ACSS was relatively high and approaching at lower cervical levels was an independent predictive factor.

Surgical Morbidity and Mortality Associated With Transoral Approach to the Cervical Spine

STUDY DESIGN

A retrospective cohort analysis of prospectively collected data.

OBJECTIVE

The aim of this study was to analyze morbidity and mortality in adult patients undergoing transoral approach using a large national database.

SUMMARY OF BACKGROUND DATA

The transoral approach to the anterior skull base and atlanto-axial cervical spine provides a direct corridor to the lower clivus, C1, C2, and occasionally C3. Due to the rarity of this approach and the unfamiliar anatomy, there is potential for significant morbidity and mortality.

METHODS

Adult patients undergoing transoral approach to the cervical spine from 2008 to 2012 were identified by the Current Procedural Terminology (CPT) code 22548 in the ACS NSQIP database. Cases with missing preoperative information were excluded. Univariate and multivariate analyses were performed to assess associated morbidity and mortality.

RESULTS

One hundred twenty-six patients underwent cervical spine and clival surgery via the transoral approach. There were a total of 27 (21.4%) postoperative complications with three (2.4%) mortalities. On multivariate analysis, there was an increased risk of complications with operative time >4 hours [odds ratio (OR) 7.8, 95% confidence interval (95% CI) 1.8-33.1, P = 0.0054] and total length of stay >5 days (OR 7.5, 95% CI 2.4-23.4, P = 0.0006).

CONCLUSION

The transoral approach carries significant risks of morbidity and mortality. Maintaining operative time <4 hours and LOS <5 days may decrease morbidity and mortality.

LEVEL OF EVIDENCE

4.

Biomechanical comparison of a novel transoral atlantoaxial anchored cage with established fixation technique - a finite element analysis

BACKGROUND

The transoral atlantoaxial reduction plate (TARP) fixation has been introduced to achieve reduction, decompression, fixation and fusion of C1-C2 through a transoral-only approach. However, it may also be associated with potential disadvantages, including dysphagia and load shielding of the bone graft. To prevent potential disadvantages related to TARP fixation, a novel transoral atlantoaxial fusion cage with integrated plate (Cage + Plate) device for stabilization of the C1-C2 segment is designed. The aims of the present study were to compare the biomechanical differences between Cage + Plate device and Cage + TARP device for the treatment of basilar invagination (BI) with irreducible atlantoaxial dislocation (IAAD).

METHODS

A detailed, nonlinear finite element model (FEM) of the intact upper cervical spine had been developed and validated. Then a FEM of an unstable BI model treated with Cage + Plate fixation, was compared to that with Cage + TARP fixation. All models were subjected to vertical load with pure moments in flexion, extension, lateral bending and axial rotation. Range of motion (ROM) of C1-C2 segment and maximum von Mises Stress of the C2 endplate and bone graft were quantified for the two devices.

RESULTS

Both devices significantly reduced ROM compared with the intact state. In comparison with the Cage + Plate model, the Cage + TARP model reduced the ROM by 82.5 %, 46.2 %, 10.0 % and 74.3 % in flexion, extension, lateral bending, and axial rotation. The Cage + Plate model showed a higher increase stresses on C2 endplate and bone graft than the Cage + TARP model in all motions.

CONCLUSIONS

Our results indicate that the novel Cage + Plate device may provide lower biomechanical stability than the Cage + TARP device in flexion, extension, and axial rotation, however, it may reduce stress shielding of the bone graft for successful fusion and minimize the risk of postoperative dysphagia. Clinical trials are now required to validate the reproducibility and advantages of our findings using this anchored cage for the treatment of BI with IAAD.

Effectiveness of postoperative wound drains in one- and two-level cervical spine fusions

Background

Cervical drains have historically been used to avoid postoperative wound and respiratory complications such as excessive edema, hematoma, infection, re-intubation, delayed extubation, or respiratory distress. Recently, some surgeons have ceased using drains because they may prolong hospital stay, operative time, or patient discomfort. The objective of this retrospective case-control series is to investigate the effectiveness of postoperative drains following one- and two-level cervical fusions.

Methods

A chart review was conducted at a single institution from 2010-2013. Outcome measures included operative time, hospital stay, estimated blood loss and incidence of wound complications (infection, hematoma, edema, and complications with wound healing or evacuation), respiratory complications (delayed extubation, re-intubation, and respiratory treatment), and overall complications (wound complications, respiratory complications, dysphagia, and other complications). Statistical analyses including independent samples t-test, chi-square, analysis of covariance, and linear regression were used to compare patients who received a postoperative drain to those who did not.

Results

The study population included 39 patients who received a postoperative drain and 42 patients who did not. There were no differences in demographics between the two groups. Patients with drains showed increased operative time (100.1 vs 69.3 min, p < 0.001), hospital stay (38.9 vs. 31.7 hrs, p = 0.021), and blood loss (62.7 vs 29.1 mL, p < 0.001) compared to patients without drains. The frequency of wound complications, respiratory complications, and overall complications did not vary significantly between groups.

Conclusions/Level of Evidence

Cervical drains may not be necessary for patients undergoing one- and two-level cervical fusion. While there were no differences in incidence of complications between groups, patients treated with drains had significantly longer operative time and length of hospital stay.

Clinical relevance

This could contribute to excessive costs for patients treated with drains, despite the lack of compelling evidence of the advantages of this treatment in the literature and in the current study.

Trans-oral approach for the management of a C2 neuroblastoma

INTRODUCTION

Neuroblastoma is the most common extra-cranial solid tumour in children. Metastasis in children to the upper cervical spine are quite rare.

CASE REPORT

An 8-year-old boy was referred to our service following a relapse of a right adrenal stage 4 neuroblastoma with a metastatic deposit in C2. This anterior tumour mass was pressing on the spinal cord with increasing pain in the base of skull, but without gross neurological deficit. He underwent urgent MRI and CT scans and then emergent surgery. The first stage was a posterior stabilization from occiput to C5 with a posterior decompression from C1 to C3 followed by a trans-oral approach to resect the main anterior tumour mass and reconstruction.

CONCLUSION

This is the first report of the use of a trans-oral approach to address a neuroblastoma lesion in the axial spine. This approach was used effectively to achieve local tumour clearance confirmed at 1-year follow-up. Pertinent information to the spinal surgeon on neuroblastoma and the use of the trans-oral approach to the axial spine are discussed.

Dysphagia following anterior cervical spinal surgery: a systematic review

Dysphagia is a common complication of anterior surgery of the cervical spine. The incidence of post-operative dysphagia may be as high as 71% within the first two weeks after surgery, but gradually decreases during the following months. However, 12% to 14% of patients may have some persistent dysphagia one year after the procedure. It has been shown that female gender, advanced age, multilevel surgery, longer operating time and severe pre-operative neck pain may be risk factors. Although the aetiology remains unclear and is probably multifactorial, proposed causes include oesophageal retraction, prominence of the cervical plate and prevertebral swelling. Recently, pre-operative tracheal traction exercises and the use of retropharyngeal steroids have been proposed as methods of reducing post-operative dysphagia. We performed a systematic review to assess the incidence, aetiology, risk factors, methods of assessment and management of dysphagia following anterior cervical spinal surgery.

Surgical treatment in a patient with Klippel-Feil syndrome and anterior cervical meningomyelocele: a case report and review of literature

INTRODUCTION

Klippel-Feil syndrome (KFS) is considered a rare developmental disorder characterized by mono- or multisegmental fusion of the cervical vertebrae which is frequently associated with diverse non-osseous, e.g. neural, visceral, cardiopulmonary and genitourinary development anomalies. Anterior cervical meningomyelocele (MMC) in KFS has only been described in two previous patients, both with non-surgical treatment.

CLINICAL PRESENTATION

We present the case of a 26-year-old female suffering from KFS, presenting with progressive bilateral C6 paraesthesias, C7 and C8 motor weakness and myelopathy. Radiological imaging revealed incomplete osseous fusion of the vertebrae C2-Th1. The spinal cord was displaced ventro-caudally through a large anterior MMC, apparently fixed at the dorsal oesophagus, severely stretching the cervical nerve roots. Surgery was indicated due to progression of the symptoms and was performed through a combined partial sternotomy and ventral anterolateral cervical approach. Intraoperatively, both division of oesophago-dural adhesions and intradural untethering of adhesions of the myelon with caudal parts of the cele were performed. Evoked somatosensory potentials improved immediately and 6-day postoperative MRI revealed a nearly complete reposition of the spinal cord in its physiological position. Genetic sequence analyses ruled out mutation of the growth and differentiation factor 6 (GDF6). Apart from slight intermittent paraesthesia, symptoms resolved almost completely within weeks after operation. Both radiological and neurological improvement remained stable at 16 months of follow-up.

CONCLUSION

KFS with anterior cervical MMC is rarely seen and may require surgery in case of clincial signs of nerve root compression or myelopathy. Osseous decompression, untethering and adhesiolysis under electrophysiological monitoring can provide sufficient radiological and clinical improvement.

The use of a zero-profile device compared with an anterior plate and cage in the treatment of patients with symptomatic cervical spondylosis

In a retrospective cohort study we compared the clinical outcome and complications, including dysphagia, following anterior cervical fusion for the treatment of cervical spondylosis using either a zero-profile (Zero-P; Synthes) implant or an anterior cervical plate and cage. A total of 83 patients underwent fusion using a Zero-P and 107 patients underwent fusion using a plate and cage. The mean follow-up was 18.6 months (sd 4.2) in the Zero-P group and 19.3 months (sd 4.1) in the plate and cage group. All patients in both groups had significant symptomatic and neurological improvement. There were no significant differences between the groups in the Neck Disability Index (NDI) and visual analogue scores at final follow-up. The cervical alignment improved in both groups. There was a higher incidence of dysphagia in the plate and cage group on the day after surgery and at two months post-operatively. All patients achieved fusion and no graft migration or nonunion was observed.

When compared with the traditional anterior cervical plate and cage, the Zero-P implant is a safe and convenient procedure giving good results in patients with symptomatic cervical spondylosis with a reduced incidence of dysphagia post-operatively.

Cite this article: Bone Joint J 2013;95-B:543–7.