Surgical results and complications in a series of 71 consecutive cervical spondylotic corpectomies

Comparison of Titanium Mesh Cage, Nano-Hydroxyapatite/Polyamide Cage, and Three-Dimensional-Printed Vertebral Body for Anterior Cervical Corpectomy and Fusion

STUDY DESIGN

A prospective nonrandomized controlled study.

OBJECTIVE

To compare the clinical and radiographic outcomes of anterior cervical corpectomy and fusion (ACCF) using titanium mesh cages (TMCs), nano-hydroxyapatite/polyamide 66 (n-HA/PA66) cages, and three-dimensional-printed vertebral bodies (3d-VBs).

BACKGROUND

Postoperative subsidence of TMCs in ACCF has been widely reported. Newer implants such as n-HA/PA66 cages and 3d-VBs using biocompatible titanium alloy powder (Ti6Al4V) have been introduced to address this issue, but their outcomes remain controversial.

PATIENTS AND METHODS

We enrolled 60 patients undergoing ACCF using TMCs, n-HA/PA66 cages, or 3d-VBs from January 2020 to November 2021. For each group, there were 20 patients. Follow-up was conducted for a minimum of 2 years. Clinical outcomes, including Japanese Orthopedic Association (JOA) scores, Neck Disability Index, and Visual Analog Scale scores, and radiographic outcomes, including function of spinal unit (FSU) height, fusion rate, and cervical alignment, were collected preoperatively and at each follow-up. A loss of FSU height ≥3mm was deemed implant subsidence. One-way analysis of variance was used for comparisons of mean values at different time points within the same group, with pairwise comparisons performed using the least significance difference method. The Mann-Whitney test was used for comparisons between groups. Categorical data such as sex, smoking status, implant subsidence, and pathology level were analyzed using the χ 2 test.

RESULTS

Postoperative FSU height loss at 2 years differed significantly among the TMC, n-HA/PA66, and 3d-VB groups, measuring 3.07 ± 1.25mm, 2.11 ± 0.73mm, and 1.46 ± 0.71mm, respectively ( P < 0.001). The rates of implant subsidence were 45%, 20%, and 10%, respectively ( P = 0.031). All patients obtained solid fusion at a 2-year follow-up. We observed statistically significant differences in Visual Analog Scale and JOA scores at 3 months postoperatively, and JOA scores at 2 years postoperatively among the 3 groups. At a 2-year follow-up, the n-HA/PA66 and the 3d-VBs groups exhibited less FSU height loss, lower subsidence rates, and demonstrated better cervical lordosis than the TMC group. No severe postoperative complications were observed in any of the patients, and no patient required reoperation.

CONCLUSION

At a 2-year follow-up after ACCF, the n-HA/PA66 and the 3d-VBs groups exhibited less FSU height loss, lower subsidence rates, and demonstrated better cervical lordosis than the TMC group. Longer-term observation of implant subsidence in ACCF using TMC, n-HA/PA66, and 3d-VB is necessary.

LEVEL OF EVIDENCE

Level III-therapeutic.

VertebralArtery Injury with Anterior Cervical Spine Operations: A Systematic Review of Risk Factors, Clinical Outcomes, and Management Strategies

OBJECTIVE

Anterior cervical spine operations are commonly performed on cervical spine pathologies and to a large extent are safe and successful. However, these surgical procedures expose the vertebral artery, posing a risk of harm to it.

METHODS

A systematic review was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to critically assess primary articles discussing treatment strategies "vertebral artery injury" AND "anterior cervical spine" and develop a management strategy based on our experience and meta-analysis of the literature. In addition, we present an illustrative case of iatrogenic vertebral artery injury presenting with 6 to 7 months' history of progressive dysphagia was transferred to our care from an outside institution.

RESULTS

Included and analyzed were 43 articles that detailed 75 cases involving vertebral artery injury (VAI) in anterior cervical spine operations. Preoperatively, frequent clinical findings reported were sensory deficit (26 patients [63.41%]), motor deficit (20 patients [48.78%]), and pain (17 patients [41.46%]). In total, 32 patients (50.00%) endured injury of their left VA, and 30 patients had a right VAI. The 2 common causes of VAI were drilling (24 patients [40.00%]) and instrumentation (8 patients [13.33%]).

CONCLUSIONS

Altogether, our review recommends repair or tamponade packing with a hemostatic agent for primary management. Should tamponade packing with a hemostatic agent be used for primary management, secondary management should entail either repair, stenting occlusion, embolization, anticoagulants, or ligation. Further examination of this treatment strategy based on a larger cohort is necessary.

The predictive value of Hounsfield units for titanium mesh cage subsidence after anterior cervical corpectomy and fusion

Objective

To investigate whether bone mineral density (BMD) measured in Hounsfield units (HUs) correlates with titanium mesh cage (TMC) subsidence after anterior cervical corpectomy and fusion (ACCF).

Methods

A total of 64 patients who underwent one or two levels of ACCF with TMC with a mean follow-up of 19.34 ± 7.86 months were analysed. HU values were measured three times in 3 different planes in the upper and lower vertebrae according to published methods. Subsidence was defined as segmental height loss of more than 3 mm. Pearson correlation analysis was performed. Receiver operating characteristic (ROC) curve analysis was used to obtain optimal thresholds. A multivariate logistic regression analysis was also conducted.

Results

Twenty-two patients (34.38%) had evidence of TMC subsidence on follow-up x-ray. The mean HU values in the subsidence group (317.34 ± 32.32, n = 22) were significantly lower than those in the nonsubsidence group (363.07 ± 25.23 n = 42, p < 0.001, t test). At last follow-up, mean disc height loss was 4.80 ± 1.16 mm in the subsidence group and 1.85 ± 1.14 mm in the nonsubsidence group (p < 0.001). There was a negative correlation between HU values and disc height loss (Pearson's coefficient -0.494, p < 0.001). HU values decreased gradually from the C3 vertebra to the C7 vertebra, and the HU values of the C5, C6, and C7 vertebrae in the nonsubsidence group were significantly higher than those in the subsidence group (p < 0.05). Furthermore, there were significant differences between the groups in the segmental angle at the last follow-up and the mean changes in segmental angle (p < 0.05). The area under the ROC curve was 0.859, and the most appropriate threshold of the HU value was 330.5 (sensitivity 100%, specificity 72.7%). The multivariate logistic regression analysis showed that older age (p = 0.033, OR = 0.879), lower LIV HU value (p < 0.001, OR = 1.053) and a greater segmental angle change (p = 0.002, OR 6.442) were significantly associated with a higher incidence of TMC subsidence after ACCF.

Conclusion

There are strong correlations between a lower HU value and TMC subsidence after ACCF. More accurate assessment of bone quality may be obtained if HU measurement can be used as a routine preoperative screening method together with DXA. For patients with HU values <330.5, a more comprehensive and cautious preoperative plan should be implemented to reduce TMC subsidence.

Head rotation as an effective compensatory technique for dysphagia caused by unilateral cervical osteophytes

Objective

Dysphagia is common in patients with cervical osteophytes. We aimed to determine whether head rotation as a compensatory technique is effective for dysphagia caused by unilateral cervical osteophytes.

Methods

We retrospectively analyzed videofluoroscopic swallowing study (VFSS) data obtained in one university hospital. Patients whose VFSS showed pharyngeal stasis by mechanical obstruction due to cervical osteophytes were selected. They were divided into a unilateral skewed osteophyte group and a diffuse central osteophyte group as confirmed by laryngoscopy or computed tomography. The effect of head rotation on swallowing was investigated. Fisher’s exact test was used for statistical analysis.

Results

Among 2876 patients who underwent VFSSs, we identified 48 patients with osteophyte-induced dysphagia. The osteophytes were centrally located in 36 patients and unilateral in the remaining 12. Ten of the patients with unilateral osteophytes showed improvement when they swallowed with head rotation toward the osteophyte side, but none of the patients with central osteophytes showed effective swallowing. A statistically significant relationship was found between swallowing with head rotation and skewed cervical osteophytes.

Conclusion

Swallowing with head rotation was safe, easy, and effective for patients with dysphagia caused by unilateral cervical osteophytes. We advise attempting this method prior to considering surgical approaches.

Iatrogenic Vascular Injury Associated with Cervical Spine Surgery: A Systematic Literature Review

BACKGROUND

Iatrogenic vascular injury is an uncommon complication of anterior and/or posterior surgical approaches to the cervical spine. Although the results of this injury may be life-threatening, mortality/morbidity can be reduced by an understanding of its mechanism and proper management.

METHODS

We conducted a literature review to provide an update of this devastating complication in spine surgery. A total of 72 articles including 194 cases of vascular lesions following cervical spine surgery between 1962 and 2021 were analyzed.

RESULTS

There were 53 female and 41 male cases (in addition to 100 cases with unreported sex) with ages ranging from 3 to 86 years. The vascular injuries were classified according to the spinal procedures, such as anterior or posterior cervical spine surgery. The interval between the symptom of the vascular injury and the surgical procedure ranged from 0 to 10 years. Only two-thirds of patients underwent intra- or postoperative imaging and the most frequently injured vessel was the vertebral artery (86.60%). Laceration was the most common lesion (41.24%), followed by pseudoaneurysm (16.49%) and dissection (5.67%). Vascular repair was performed in 114 patients. The mortality rate was 7.22%, and 18.04% of patients had 1 or more other complications. Most presumed causes of vascular lesions were by instrumentation/screw placement (31.44%) or drilling (20.61%). Sixteen patients had an anomalous artery. Direct microsurgical repair was achieved in only 15 cases.

CONCLUSIONS

Despite increased anatomical knowledge and advanced imaging techniques, we need to consider the risk of vascular injury as a surgical complication in patients with cervical spine pathologies.

Bibliometric and Visualized Analysis of Scientific Publications on Ossification of the Posterior Longitudinal Ligament Based on Web of Science

BACKGROUND

In recent years, there has been increasing study of ossification of the posterior longitudinal ligament (OPLL), leading to many articles on this topic. We aimed to identify trends in OPLL-related research and to analyze the most highly cited scientific articles on OPLL.

METHODS

We searched the Web of Science Core Collection database for all articles on OPLL. The years of publication, countries, journals, institutions, and total citations were extracted and analyzed. Results related to countries, institutions, and keywords were subjected to co-occurrence analysis using VOSviewer software. The top 100 most-cited articles on OPLL were analyzed.

RESULTS

A total of 876 articles related to OPLL were identified. The frequency of publication on OPLL has increased substantially over time. Among all countries, Japan has contributed the most articles on OPLL (n = 349). The most productive institution has been Hirosaki University (n = 57). Spine topped the list of journals and has published 120 OPLL-related articles, which received 4221 total citations. The surgical treatment of OPLL has been the most common research focus in the OPLL literature.

CONCLUSIONS

The scientific literature on OPLL has rapidly expanded in recent years. This study represents the first bibliometric analysis of scientific articles on OPLL and can serve as a useful guide to clinicians and researchers in the field.

DEGENERATIVE CERVICAL MYELOPATHY: A REVIEW OF CURRENT CONCEPTS

ABSTRACT Herbert von Luschka, a German anatomist, was the first to describe the developmental changes in the anatomical structures of the cervical spine. Degenerative cervical myelopathy (DCM) represents a collection of pathological entities that cause compression of the cervical spinal cord, resulting in a clinical syndrome typified by spasticity, hyperreflexia, pathologic reflexes, finger/hand clumsiness, gait disturbance and sphincter dysfunction. In the cervical spine, certain patients are more likely to have myelopathy due to a congenitally narrowed cervical spine canal. Degenerative changes are more common at C5 and C6 or C6 and C7 due to the increased motion at these levels. Additional contributors to canal narrowing are infolding of the ligamentum flavum, olisthesis, osteophytes, and facet hypertrophy. Myelopathy will develop in approximately 100% of patients with canal stenosis greater than 60% (less than 6 mm sagittal disc cord space). Classically it has an insidious onset, progressing in a stepwise manner with functional decline. Without treatment, patients may progress toward significant paralysis and loss of function. Treatment requires surgery with either anterior or posterior decompression of the area of narrowing, and probable fusion. Factors of a poor prognosis include symptoms lasting for more than 18 months, increased range of motion in the cervical spine, and female gender. In this study, we give an overview of the state-of-the-art in DCM, with a focus on the pathophysiology, clinical presentation, differential diagnosis, imaging evaluation, natural history, treatment options and complications. Level of evidence III; Review article.

In vivo evaluation of porous nanohydroxyapatite/polyamide 66 struts in a goat cervical fusion model

The hollow cylindrical nanohydroxyapatite/polyamide 66 strut (n-HA/PA66) has been used clinically for anterior cervical reconstruction. However, rates of occurrence of a “radiolucent gap” between the dense strut and adjacent endplates were reported. The aim of this in vivo study was to evaluate the viability and advantages of the novel porous n-HA/PA66 strut. The goat C3/4 partial discectomy and fusion model was built, and two groups of n-HA/PA66 struts were implanted into C3/4: group 1, porous n-HA/PA66 strut; and group 2, hollow cylindrical n-HA/PA66 strut filled with autogenous cancellous bone. CT evaluation was performed to assess the fusion status after 12 and 24 weeks. The cervical spines were harvested. Histomorphological analysis was performed to determine new bone formation. Biomechanical testing was performed to determine range of motion (ROM). CT confirmed the disappearance of the boundary of the porous strut and host bone, while the radiolucent gap remained clearly discernible in the dense strut group. The mean CT fusion scores of the porous group were significantly higher. Histologic evaluation showed that the porous struts promoted better osteointegration. Calcein fluorochrome labelling indicated faster bone ingrowth in the porous struts. Biomechanical tests revealed that the porous struts had significantly reduced micromotion. The porous n-HA/PA66 strut could offer interesting potential for cervical reconstruction after corpectomy.

Surgical treatment of anterior cervical osteophytes causing dysphagia

PURPOSE

Dysphagia due to anterior cervical osteophytes is a rare condition. However, it can become serious enough to permanently impair the quality of life up to making normal food intake impossible. If conservative treatment fails, there is the option of surgical resection of the osteophytes. The objective of this study was to assess the outcomes of resections of anterior cervical osteophytes causing spondylogenic dysphagia, taking literature into consideration.

METHOD

Resection of anterior cervical osteophytes using a standard anterior approach was performed in 14 consecutive patients with spondylogenic dysphagia between 2009 and 2015. Indomethacin or radiation was used to prevent recurrence. Imaging and clinical data were collected in follow-up examinations over an average of 50 months.

RESULTS

The osteophytes were sufficiently resected in all cases. Anterior plates were placed in three patients due to pronounced segmental mobility. Five patients were given recurrence prevention in the form of indomethacin, nine with radiation. One patient required revision surgery for a hematoma. No other serious complications were observed. All patients had significant improvement of their symptoms. No recurrences or signs of increasing instability were found during the follow-up period.

CONCLUSION

When conservative treatment fails, surgical resection of cervical osteophytes is a sufficient method for treating spondylogenic dysphagia. High patient satisfaction and improvement of the quality of life are achieved with a low complication rate. Routine additional stabilization has been discussed as recurrence prevention. Prophylaxis using indomethacin or radiation, known primarily from hip replacement, also appears to be an option.

[Effects of a new anatomical adaptive titanium mesh cage on supportive load at the cervical endplate: a morphological and biomechanical study]

OBJECTIVE

To assess the geometrical matching of a new anatomical adaptive titanium mesh cage (AA-TMC) with the endplate and its effect on cervical segmental alignment reconstruction in single- and two-level anterior cervical corpectomy and fusion (ACCF) and compare the compressive load at the endplate between the AA-TMC and the conventional titanium mesh cage (TMC).

METHODS

Twelve cervical cadaveric specimens were used to perform single- and two-level ACCF. The interbody angle (IBA), interbody height (IBH) and the interval between the AA-TMC and the endplate were evaluated by comparison of the pre- and postoperative X-ray images. The maximum load at the endplate was compared between the AA-TMC and TMC based on American Society for Testing and Materials (ASTM) F2267 standard.

RESULTS

No significant differences were found between the preoperative and postoperative IBA and IBH in either single-level ACCF (11.62°±2.67° vs 12.13°±0.69° and 23.90±2.18 mm vs 24.23±1.13 mm, respectively; P &gt; 0.05) or two-level ACCF (15.63°±5.06° vs 16.16°±1.05°and 42.93±3.51 mm vs 43.04±1.70 mm, respectively; P &gt; 0.05). The mean interval between the AA-TMC and the endplate was 0.37 ± 0.3 mm. Compared to the conventional TMC, the use of AA-TMC significantly increased the maximum load at the endplate in both single-level ACCF (719.7±5.5 N vs 875.8±5.2 N, P &lt; 0.05) and two-level ACCF (634.3±5.9 N vs 873±6.1 N, P &lt; 0.05).

CONCLUSIONS

The use of AA-TMC in single-level and two-level ACCF can significantly increase the maximum load at the endplate to lower the possibility of implant subsidence and allows effective reconstruction of the cervical alignment.

Characteristics and Clinical Course of Dysphagia Caused by Anterior Cervical Osteophyte

OBJECTIVE

To investigate swallowing characteristics of patients with dysphagia caused by anterior cervical osteophytes (ACOs) and compare clinical courses according to treatment options.

METHODS

A retrospective analysis of 1,866 videofluoroscopic swallowing studies (VFSS) of patients with ACOs from electronic medical records was performed. Patients with other diseases that could explain the dysphagia were excluded. Dysphagia characteristics and severity and clinical and radiological characteristics of subjects with ACOs were evaluated. Dysphagia characteristics and clinical course were compared among three treatment groups: surgical treatment, swallowing rehabilitation, and conservative treatment.

RESULTS

Subjects were 22 men and 1 woman with a mean age of 78.69±8.01 years. The mean osteophyte thickness was 9.07±3.84 mm. It was significantly thicker in the surgical group than that in other groups (p=0.01). ACOs were most frequently found at C5 level. This level also had the thickest osteophytes. However, videofluoroscopic dysphagia scales (VDS) were not significantly different among the three treatment groups. The pharyngeal phase score of the VDS was significantly higher in the surgical group (p=0.041). Dysphagia severity was decreased significantly in the surgical group at 3 months after the initial VFSS (p=0.004).

CONCLUSION

The main swallowing characteristics in patients with ACOs were dysphagia features of the pharyngeal phase, including inappropriate airway protection, decreased laryngeal elevation, and reduced epiglottis inversion. When determining treatment options, it may be helpful to consider dysphagia severity at pharyngeal phase and osteophyte thickness.

Covered Stent to Salvage Iatrogenic Vertebral Artery Injury with Uncontrolled Bleeding in the Operating Room Setting

BACKGROUND

Iatrogenic vertebral artery injury is an uncommon but well recognized complication during cervical spine surgery. Intraoperative surgical repair is extremely challenging, and options for endovascular repair are limited because of the lack of proper equipment in the operating room setting.

CASE DESCRIPTION

A 53-year-old woman who presented with myelopathy underwent anterior cervical diskectomy and fusion of C3-7. A significant laceration injury of the left vertebral artery was encountered during surgery, which was salvaged by intraoperative endovascular repair with a covered stent under portable fluoroscopy guidance. The salvage and repair led to the rest of the surgery being finished as planned preoperatively without any consequences.

CONCLUSIONS

Vertebral artery injury is an uncommon but severe complication of cervical spine surgery. For uncontrolled bleeding, intraoperative endovascular repair with portable fluoroscopy is warranted and possible. A covered stent can seal the laceration and stop the bleeding completely which enables completion of the surgery.

Anterior cervical spine surgery-associated complications in a retrospective case-control study

Anterior cervical spine procedures have been associated with satisfactory outcomes. However, the occurrence of troublesome complications, although uncommon, needs to be taken into consideration. The purpose of our study was to assess the actual incidence of anterior cervical spine procedure-associated complications and identify any predisposing factors. A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in our retrospective, case-control study. The diagnosis was cervical radiculopathy, and/or myelopathy due to degenerative disc disease, cervical spondylosis, or traumatic cervical spine injury. All our participants underwent surgical treatment, and complications were recorded. The most commonly performed procedure (79%) was anterior cervical discectomy and fusion (ACDF). Fourteen patients (12.3%) underwent anterior cervical corpectomy and interbody fusion, seven (6.1%) ACDF with plating, two (1.7%) odontoid screw fixation, and one anterior removal of osteophytes for severe Forestier's disease. Mean follow-up time was 42.5 months (range, 6-78 months). The overall complication rate was 13.2%. Specifically, we encountered adjacent intervertebral disc degeneration in 2.7% of our cases, dysphagia in 1.7%, postoperative soft tissue swelling and hematoma in 1.7%, and dural penetration in 1.7%. Additionally, esophageal perforation was observed in 0.9%, aggravation of preexisting myelopathy in 0.9%, symptomatic recurrent laryngeal nerve palsy in 0.9%, mechanical failure in 0.9%, and superficial wound infection in 0.9%. In the vast majority anterior cervical spine surgery-associated complications are minor, requiring no further intervention. Awareness, early recognition, and appropriate management, are of paramount importance for improving the patients' overall functional outcome.

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.

Single-Level Anterior Cervical Corpectomy and Fusion Using a New 3D-Printed Anatomy-Adaptive Titanium Mesh Cage for Treatment of Cervical Spondylotic Myelopathy and Ossification of the Posterior Longitudinal Ligament: A Retrospective Case Series Study

BACKGROUND The aim of this study was to evaluate the clinical and radiological outcomes of the use of a new 3D-printed anatomy-adaptive titanium mesh cage (AA-TMC) for single-level anterior cervical corpectomy and fusion (ACCF) in patients with cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL). MATERIAL AND METHODS We retrospectively reviewed the records of 15 consecutive patients who underwent ACCF surgeries with AA-TMC implantation. The Japanese Orthopedic Association (JOA) scoring system, a visual analogue scale (VAS), the mean intervertebral height (MIBH) of the surgical segments, and the surgical segmental angle (SSA) were recorded preoperatively, immediately after surgery and at the final follow-up visit. The outcomes of these parameters at different time points were compared. RESULTS Six months after ACCF surgery, solid bony fusions of the surgical level were achieved in all patients. The mean MIBH was 21.05±1.99 mm preoperatively, 27.51±1.44 mm immediately after surgery (P<0.05), and 26.85±1.25 mm at the last follow-up visit (P<0.05). At the last follow-up visit, none of the AA-TMCs exhibited severe subsidence (>3 mm). The mean SSA was 6.66±7.08° preoperatively, 14.03±2.3° immediately after surgery (P<0.05), and 15.09±2.1° at the final follow-up visit (P>0.05). The mean VAS and JOA scores were 6.6±1.26 and 10.47±2.07, respectively, preoperatively and 2.47±1.3 and 13.6±1.96 immediately after surgery, respectively (P<0.05). At the last follow-up visit, the mean VAS and JOA were further restored to 1.67±1.18 and 14.9±1.39, respectively (P<0.05). CONCLUSIONS The application of the AA-TMC in single-level ACCF significantly relieved symptoms of CSM and OPLL. The rational design of the AA-TMC restores the surgical segmental curvature, maintains the intervertebral height, and prevents postoperative subsidence-related complications.

Effects of Titanium Mesh Cage End Structures on the Compressive Load at the Endplate Interface: A Cadaveric Biomechanical Study

Background

This study aimed to evaluate whether obliquely angled and ring-shaped titanium mesh cage (TMC) end structures can improve the compressive load on the endplate interface in anterior cervical corpectomy and fusion (ACCF).

Material/Methods

A total of 23 volunteers underwent cervical lateral x-ray. The oblique angle of the superior endplate was measured, which was used to construct the gradient of the TMC end. Forty-two fresh cadaveric vertebral bodies were harvested and randomly distributed among four TMC groups with different ends. The baseline indicators of bone mineral density and anteroposterior and transverse dimensions were recorded. The superior endplate was placed at an angle of 12° when performing uniaxial compression testing. The maximum loads of the four TMCs were assessed.

Results

There were no significant differences among the groups regarding the baseline indicators. The conventional TMC had the lowest maximum load (1362.3±221.78 N, p<0.05), whereas the TMC with an obliquely end ring had the highest maximum load (2095.82±285.64 N, p<0.05). The maximum loads of the TMCs with oblique footprints and flat end ring were much higher than that of the conventional TMC (p<0.05) but significantly lower than that of the TMC with the obliquely end ring (p<0.05), with average values of 1806.91±246.98 N and 1725.3±213.33 N, respectively.

Conclusions

Both the ring shape and oblique angle of the TMC end contributed to an increase in compressive force and are advocated for use in TMC structure optimization to decrease the incidence of TMC subsidence in ACCF.

Vertebral Artery Injury in C2-3 Epidural Schwannoma Resection: A Case Report and Literature Review

The incidence of vertebral artery (VA) injury (VAI) in posterior approach tumor resection surgery is extremely rare, but it can lead to serious complication. In this case, a 57-year-old man underwent surgery for resection of the tumor involving left epidural space and neural foramen at C2-3 level. Iatrogenic VAI occurred suddenly during tumor resection procedure using pituitary forceps. Immediate local hemostasis and maintaining of perfusion for reducing the risk of posterior circulation ischemia were performed. Intraoperative angiogram of both VA and emergent trapping embolization were done as well. It may reduce the risk of immediate postop complication, and further delayed occurrence. The patient had no complication after VAI by appropriate intraoperative management. Preoperative angiographic work up and preparation of endovascular team cooperation are positively necessary as well as a warning for the VAI during cervical spine surgery.

Misplaced Cervical Screws Requiring Reoperation

STUDY DESIGN

A multicenter, retrospective case series.

OBJECTIVE

In the past several years, screw fixation of the cervical spine has become commonplace. For the most part, this is a safe, low-risk procedure. While rare, screw backout or misplaced screws can lead to morbidity and increased costs. We report our experiences with this uncommon complication.

METHODS

A multicenter, retrospective case series was undertaken at 23 institutions in the United States. Patients were included who underwent cervical spine surgery from January 1, 2005, to December 31, 2011, and had misplacement of screws requiring reoperation. Institutional review board approval was obtained at all participating institutions, and detailed records were sent to a central data center.

RESULTS

A total of 12 903 patients met the inclusion criteria and were analyzed. There were 11 instances of screw backout requiring reoperation, for an incidence of 0.085%. There were 7 posterior procedures. Importantly, there were no changes in the health-related quality-of-life metrics due to this complication. There were no new neurologic deficits; a patient most often presented with pain, and misplacement was diagnosed on plain X-ray or computed tomography scan. The most common location for screw backout was C6 (36%).

CONCLUSIONS

This study represents the largest series to tabulate the incidence of misplacement of screws following cervical spine surgery, which led to revision procedures. The data suggest this is a rare event, despite the widespread use of cervical fixation. Patients suffering this complication can require revision, but do not usually suffer neurologic sequelae. These patients have increased cost of care. Meticulous technique and thorough knowledge of the relevant anatomy are the best means of preventing this complication.

[Results to 4-year follow-up of the treatment of the cervical stenosis by corpectomy, titanium mesh cage and anterior plate fixation]

BACKGROUND

Cervical spondylotic myelopathy is caused by cervical stenosis. Several techniques have been described for the treatment of multilevel disease, such as the anterior corpectomy with titanium mesh cage and anterior cervical plate placement, which has the advantage of performing a wider decompression and using the same bone as graft. However, it has caused controversy since the collapse of the mesh cage continues being a major limitation of this procedure.

MATERIAL AND METHOD

A prospective 4-year follow-up study was conducted in 7 patients diagnosed with cervical stenosis, who were treated surgically by one level corpectomy with titanium mesh cage and anterior cervical plate placement, evaluating them by radiographs and clinical scales.

RESULTS

7 patients, 5 women and 2 males were studied. The most common level was C5 corpectomy (n=4). The Neck Disability Index (NDI) preoperative average was 30.01±24.32 and 4-year postoperative 16.90±32.05, with p=0.801. The preoperative and 4-year postoperative Nürick was 3.28± 48 and 3.14±1.21 respectively, with p=0.766. Preoperative lordosis was 14.42±8.03 and 4-year postoperative 17±11.67 degrees, with p=0.660. The immediate postoperative and 4-year postoperative subsidence was 2.69±2.8 and 6.11±1.61 millimeters respectively, with p=0.0001.

CONCLUSIONS

Despite the small sample, the subsidence of the mesh cage is common in this procedure. No statistically significant changes were observed in the lordosis or Nürick scale and NDI.

Vertebral Artery Injury during Routine Posterior Cervical Exposure: Case Reports and Review of Literature

Study Design Case series. Objective We report the unusual occurrence of vertebral artery injury (VAI) during routine posterior exposure of the cervical spine. The importance of preoperative planning to identify the course of the bilateral vertebral arteries during routine posterior cervical spine surgery is emphasized. Methods VAI is a rare but potentially devastating complication of cervical spinal surgery. Most reports of VAI are related to anterior surgical exposure or screw placement in the posterior cervical spine. VAI incurred during posterior cervical spinal exposure surgery is not adequately addressed in the existing literature. Two cases of VAI that occurred during routine posterior exposure of the cervical spine in the region of C2 are described. Results VAI was incurred unexpectedly in the region of the midportion of the posterior C1-C2 interval during the initial surgical exposure phase of the operation. An aberrant vertebral artery course in the V2 anatomical section in the region between C1 and C2 intervals was identified postoperatively in both patients. A literature review demonstrates a relatively high incidence of vertebral artery anomalies in the upper cervical spine; however, the literature is deficient in reporting vertebral artery injury in this region. Recommendations for preoperative vertebral artery imaging also remain unclear at this time. Conclusions Successful management of this unexpected complication was achieved in both cases. This case report and review of the literature highlights the importance of preoperative vertebral artery imaging and knowledge of the course of the vertebral arteries prior to planned routine posterior exposure of the upper cervical spine. In both cases, aberrancy of the vertebral artery was present and not investigated or detected preoperatively.

Partial Epiglottoplasty for Pharyngeal Dysphagia due to Cervical Spine Pathology

OBJECTIVE

To examine the role of epiglottoplasty in patients with pharyngeal dysphagia due to pharyngeal crowding from cervical spine pathology and to assess swallowing outcomes following epiglottoplasty.

STUDY DESIGN

Retrospective case series.

SETTING

Academic tertiary care medical center.

SUBJECTS AND METHODS

Dysphagia can occur in patients with cervical spine pathology because of hypopharyngeal crowding. Swallowing studies, such as modified barium swallow study and fiberoptic endoscopic evaluation of swallowing, may demonstrate a nonretroflexing epiglottis owing to cervical spine osteophytes or hardware, thus impeding pharyngeal bolus transit. We performed partial epiglottoplasties in a series of these patients. A retrospective review of swallowing outcomes was performed to assess the efficacy of this surgery in this patient population.

RESULTS

Epiglottic dysfunction causing dysphagia due to cervical spine pathology was diagnosed by modified barium swallow study and/or fiberoptic endoscopic evaluation of swallowing in 12 patients. Findings included hypopharyngeal crowding because of cervical osteophytes (n = 8) or cervical hardware (n = 4) associated with absent epiglottic retroflexion and retained vallecular residue. Partial epiglottoplasty resulted in significant reduction of vallecular residue and a significant increase in functional swallow outcomes without an increase in swallow morbidity.

CONCLUSION

There is a role for partial epiglottoplasty in patients with dysphagia attributed to hypopharyngeal crowding from cervical spine pathology. Surgery enables reduced vallecular residue and improved functional swallowing outcomes.

Artificial disc and vertebra system: a novel motion preservation device for cervical spinal disease after vertebral corpectomy

OBJECTIVE

To determine the range of motion and stability of the human cadaveric cervical spine after the implantation of a novel artificial disc and vertebra system by comparing an intact group and a fusion group.

METHODS

Biomechanical tests were conducted on 18 human cadaveric cervical specimens. The range of motion and the stability index range of motion were measured to study the function and stability of the artificial disc and vertebra system of the intact group compared with the fusion group.

RESULTS

In all cases, the artificial disc and vertebra system maintained intervertebral motion and reestablished vertebral height at the operative level. After its implantation, there was no significant difference in the range of motion (ROM) of C(3-7) in all directions in the non-fusion group compared with the intact group (p>0.05), but significant differences were detected in flexion, extension and axial rotation compared with the fusion group (p<0.05). The ROM of adjacent segments (C(3-4), C(6-7)) of the non-fusion group decreased significantly in some directions compared with the fusion group (p<0.05). Significant differences in the C(4-6) ROM in some directions were detected between the non-fusion group and the intact group. In the fusion group, the C(4-6) ROM in all directions decreased significantly compared with the intact and non-fusion groups (p<0.01). The stability index ROM (SI-ROM) of some directions was negative in the non-fusion group, and a significant difference in SI-ROM was only found in the C(4-6) segment of the non-fusion group compared with the fusion group.

CONCLUSION

An artificial disc and vertebra system could restore vertebral height and preserve the dynamic function of the surgical area and could theoretically reduce the risk of adjacent segment degeneration compared with the anterior fusion procedure. However, our results should be considered with caution because of the low power of the study. The use of a larger sample should be considered in future studies.

Kinematic changes in swallowing after surgical removal of anterior cervical osteophyte causing Dysphagia: a case series

This retrospective case series included five patients who underwent surgical resection of the cervical anterior osteophyte due to dysphagia. Videofluoroscopic swallowing studies (VFSSs) were performed before and after surgery on each patient, and kinematic analysis of the video clips from the VFSS of a 5-mL liquid barium swallow was carried out. Functional oral intake improved after surgery in 3/4 patients who had required a modified diet before surgery. Kinematic analysis showed increases in the maximal hyoid vertical movement length (13.16±5.87 to 19.09±4.77 mm, p=0.080), hyoid movement velocities (170.24±84.71 to 285.53±104.55 mm/s, p=0.043), and upper esophageal sphincter opening width (3.97±0.42 to 6.39±1.32 mm, p=0.043) after surgery. In conclusion, improved upper esophageal sphincter opening via enhancement of hyoid movement after cervical anterior osteophyte resection may be the kinetic mechanism of improved swallowing function.

A new method to determine whether ossified posterior longitudinal ligament can be resected completely and safely: spinal canal "Rule of Nine" on axial computed tomography

PURPOSE

To introduce the new method of spinal canal "Rule of Nine" on axial computed tomography (CT) to determine whether ossified posterior longitudinal ligament (OPLL) can be resected completely and safely.

METHODS

From January 2008 to January 2013, we retrospectively analyzed 308 patients with cervical OPLL who underwent anterior corpectomy. Patients were examined by cervical plain X-ray, CT, and magnetic resonance imaging. The characteristics of OPLL on axial CT, dural mater adhesion and ossification, complete resection of the ossified mass, cerebrospinal fluid (CSF) leakage, spinal cord injury (SCI), and postoperative outcome were all studied. OPLL was characterized at the maximum ossified level using spinal canal "Rule of Nine" on axial CT.

RESULTS

OPLL was completely and safely resected in 129 patients, whose ossified mass was within the safety zone. No CSF leakage or SCI occurred. The most ossified material was resected when OPLL was within the danger zone in 21 patients. There were two cases of SCI and seven of CSF leakage. In the other 158 patients, the ossified mass was within the intermediate zone. In 96 patients the width of the ossified mass was <2 resection units. It was completely resected and one case had CSF leakage. In the other 62 cases, the ossified mass was >2 resection units and there were nine cases of CSF leakage. CSF leakage and SCI increased significantly when the ossified mass was ≥6 units. The inter- and intraobserver κ values were 0.76 and 0.84, respectively, showing a good reliability.

CONCLUSIONS

Our new method can be used to determine whether OPLL can be resected completely and safely, and identify potential risks and complications.

Evaluation of anterior cervical reconstruction with titanium mesh cages versus nano-hydroxyapatite/polyamide66 cages after 1- or 2-level corpectomy for multilevel cervical spondylotic myelopathy: a retrospective study of 117 patients

Objective

To retrospectively compare the efficacy of the titanium mesh cage (TMC) and the nano-hydroxyapatite/polyamide66 cage (n-HA/PA66 cage) for 1- or 2-level anterior cervical corpectomy and fusion (ACCF) to treat multilevel cervical spondylotic myelopathy (MCSM).

Methods

A total of 117 consecutive patients with MCSM who underwent 1- or 2-level ACCF using a TMC or an n-HA/PA66 cage were studied retrospectively at a mean follow-up of 45.28±12.83 months. The patients were divided into four groups according to the level of corpectomy (1- or 2-level corpectomy) and cage type used (TMC or n-HA/PA66 cage). Clinical and radiological parameters were used to evaluate outcomes.

Results

At the one-year follow-up, the fusion rate in the n-HA/PA66 group was higher, albeit non-significantly, than that in the TMC group for both 1- and 2-level ACCF, but the fusion rates of the procedures were almost equal at the final follow-up. The incidence of cage subsidence at the final follow-up was significantly higher in the TMC group than in the n-HA/PA66 group for the 1-level ACCF (24% vs. 4%, p = 0.01), and the difference was greater for the 2-level ACCF between the TMC group and the n-HA/PA66 group (38% vs. 5%, p = 0.01). Meanwhile, a much greater loss of fused height was observed in the TMC group compared with the n-HA/PA66 group for both the 1- and 2-level ACCF. All four groups demonstrated increases in C2-C7 Cobb angle and JOA scores and decreases in VAS at the final follow-up compared with preoperative values.

Conclusion

The lower incidence of cage subsidence, better maintenance of the height of the fused segment and similar excellent bony fusion indicate that the n-HA/PA66 cage may be a superior alternative to the TMC for cervical reconstruction after cervical corpectomy, in particular for 2-level ACCF.

Use of Piezosurgery for removal of retrovertebral body osteophytes in anterior cervical discectomy

BACKGROUND CONTEXT

The relatively new technique of Piezosurgery is based on microvibrations, generated by the piezoelectrical effect, which results in selective bone cutting with preservation of adjacent soft tissue.

PURPOSE

To study the applicability of Piezosurgery in anterior cervical discectomy with fusion (ACDF) surgery.

STUDY DESIGN/SETTING

Prospective clinical study at the neurosurgical department of the University of Freiburg, Germany.

PATIENT SAMPLE

Nine patients with cervical disc herniation and retrovertebral osteophytes who underwent ACDF surgery.

OUTCOME MEASURES

Piezosurgery was evaluated with respect to practicability, safety, preciseness of bone cutting, and preservation of adjacent neurovascular tissue. Pre- and postoperative clinical and radiological data were assessed.

METHODS

Piezosurgery was supportively used in ACDF in nine patients with either radiculopathy or myelopathy from disc herniation or ventral osteophytes. After discectomy, osteophytes were removed with Piezosurgery to decompress the spinal canal and the foramina. Angled inserts were used, allowing for cutting even retrovertebral osteophytes.

RESULTS

In all nine cases, Piezosurgery cut bone selectively with no damage to nerve roots, dura, or posterior longitudinal ligament. None of the patients experienced any new neurological deficit after the operation. The handling of the instrument was safe and the cut precise. Osteophytic spurs, even retrovertebral ones that generally only can be approached via corpectomies, could be safely removed because of the angled inserts through the disc space. Currently, a slightly prolonged operation time was observed for Piezosurgery. Furthermore, the design of the handpiece could be further improved to facilitate the intraoperative handling in ACDF.

CONCLUSIONS

Piezosurgery proved to be a useful and safe technique for selective bone cutting and removal of osteophytes with preservation of neuronal and soft tissue in ACDF. In particular, the angled inserts were effective in cutting bone spurs behind the adjacent vertebra which cannot be reached with conventional rotating burs.

Vertebral artery anomaly and injury in spinal surgery

STUDY DESIGN

Systematic review.

STUDY RATIONALE

The purpose of this review is to further define the published literature with respect to vertebral artery (VA) anomaly and injury in patients with degenerative cervical spinal conditions.

OBJECTIVES

In adult patients with cervical spine or degenerative cervical spine disorders receiving cervical spine surgery, what is the incidence of VA injury, and among resulting VA injuries, which treatments result in a successful outcome and what percent are successfully repaired?

MATERIALS AND METHODS

A systematic review of pertinent articles published up to April 2013. Studies involving traumatic onset, fracture, infection, deformity or congenital abnormality, instability, inflammatory spinal diseases, or neoplasms were excluded. Two independent reviewers assessed the level of evidence quality using the Grades of Recommendation Assessment, Development and Evaluation criteria; disagreements were resolved by consensus.

RESULTS

From a total of 72 possible citations, the following met our inclusion criteria and formed the basis for this report. Incidence of VA injuries ranged from 0.20 to 1.96%. None of the studies reported using preoperative imaging to identify anomalous or tortuous VA. Primary repair and ligation were the most effective in treating VA injuries.

CONCLUSION

The incidence of VA injuries in degenerative cervical spinal surgery might be as high as 1.96% and is likely underreported. Direct surgical repair is the most effective treatment option. The most important preventative technique for VA injuries is preoperative magnetic resonance imaging or computed tomography angiographic imaging to detect VA anomalies. The overall strength of evidence for the conclusions is low.

Anterior cervical intercorporal fusion in patients with osteoporotic or tumorous fractures using a cement augmented cervical plate system: first results of a prospective single-center study

STUDY DESIGN

Prospective observational clinical study.

OBJECTIVE

The aim of this study is to evaluate the technical feasibility and the safety of additional cement augmentation of anterior cervical implants in patients with poor bone quality because of osteoporosis or tumor infiltration.

SUMMARY OF BACKGROUND DATA

With an increasing number of elderly patients in spinal surgery the problem of implant dislocation after cervical instrumentation will become a more and more important problem. Whereas in the thoracolumbar area cement augmented screws have become widely accepted to ensure a rigid fixation in patients with reduced bone quality there are no data concerning an additional intravertebral cement augmentation after cervical plating.

METHODS

Nine patients (4 males, 5 females, mean age 62.8 y) with newly diagnosed fractures of 1 or 2 cervical vertebrae because of tumor infiltration (6 cases) or osteoporosis (3 cases) were included in our study. A standard 1-level or 2-level cervical corpectomy with vertebral body replacement by an in situ expandable titanium cage and additional anterior plating was carried out. After this, additional cement augmentation was performed as a vertebroplasty of the anterior two thirds of the cranial and caudal adjacent vertebra by a new anterior hole. The cement should enclose the screws and stabilize the endplates of the adjacent vertebrae. Follow-up comprised clinical examinations, SF-36 questionnaire and visual analog scale 3, 6, and 12 months after surgery. Cervical spine radiographs were obtained 3 and 6 months after surgery and computed tomography scans 6 and 12 months after surgery.

RESULTS

The median follow-up was 10 months with a range of 4-18 months. There was no intraoperative cement leakage into the spinal canal. The visual analog scale decreased from 8.2 to 4.2 at 6 months, physical and mental component summaries of SF-36 increased significantly from 27.7 to 36.1 and 31.5 to 48.6 at 6 months, respectively. Loosening of screws or plates was not detected throughout the whole observation period. There was 1 subsidence of a titanium cage into an adjacent vertebra without any clinical consequences. There was no adjacent fracture during the follow-up period and other surgical interventions or revisions were not necessary in any patient.

CONCLUSIONS

In patients with severe osteoporosis or in patients with advanced tumor disease, excellent surgical, clinical, and radiologic results are possible following our method. In our opinion, a second-step posterior approach can be avoided by this technique.

Evaluation of a new type of titanium mesh cage versus the traditional titanium mesh cage for single-level, anterior cervical corpectomy and fusion

STUDY DESIGN

A retrospective review of prospectively collected data in an academic institution.

OBJECTIVE

To evaluate the safety and efficacy of a new type of titanium mesh cage (TMC) in single-level, anterior cervical corpectomy and fusion (ACCF).

METHODS

Fifty-eight patients consecutive with cervical spondylotic myelopathy (CSM) from cervical degenerative spondylosis and isolated ossification of the posterior longitudinal ligament were treated with a single-level ACCF using either a new type of TMC (28 patients, group A) or the traditional TMC (30 patients, group B). We evaluated the patients for TMC subsidence, cervical lordosis (C2-C7 Cobb and Cobb of fused segments) and fusion status for a minimum of 30 months postoperatively based on spine radiographs. In addition, neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) scores. Neck pain was evaluated using a 10-point visual analog scale (VAS).

RESULTS

The loss of height of the fused segments was less for group A than for group B (0.8 ± 0.3 vs. 2.8 ± 0.4 mm) (p < 0.01); also, there was a lower rate of severe subsidence (≥3 mm) in group A (4 %, 1/28) than in group B (17 %, 5/30) (p < 0.01). There were no differences in the C2-C7 Cobb and Cobb of fused segments between the groups preoperatively or at final follow-up (p > 0.05), but the Cobb of fused segments immediately postoperative were significantly less for group B than for group A (p < 0.01). All patients, however, had successful fusion (100 %, each). Both groups had marked improvement in the JOA score after operation (p < 0.01), with no significant differences in the JOA recovery ratio (p > 0.05). The postoperative VAS neck pain scores for group A were significantly less than that for group B (p < 0.05); severe subsidence was correlated with neck pain.

CONCLUSIONS

The new type of TMC provides comparable clinical results and fusion rates with the traditional TMC for patients undergoing single-level corpectomy. The new design TMC decreases postoperative subsidence (compared to the traditional TMC); the unique design of the new type of TMC matches the vertebral endplate morphology which appears to decrease the severity of subsidence-related neck pain in follow-up.

Morphological character of cervical spine for anterior transpedicular screw fixation

BACKGROUND

Anterior cervical interbody grafts/cages combined with a plate were frequently used in multilevel discectomies/corpectomies. In order to avoid additional posterior stabilization in patients who undergo anterior reconstructive surgery, an anterior cervical transpedicular screw fixation, which offers higher stability is desirable. We investigated in this study the anatomical (morphologic) characters for cervical anterior transpedicular screw fixation.

MATERIALS AND METHODS

Left pedicle parameters were measured on computed tomography (CT) images based on 36 cervical spine CT scans from healthy subjects. The parameters included outer pedicle width (Distance from lateral to medial pedicle surface in the coronal plane), outer pedicle height (OPH) (Distance from upper to lower pedicle surface in the sagittal plane), maximal pedicle axis length (MPAL), distance transverse insertion point (DIP), distance of the insertion point to the upper end plate (DIUP), pedicle sagittal transverse angle (PSTA) and pedicle transverse angle (PTA) at C3 to C7.

RESULTS

The values of outer pedicle width and MPAL in males were larger than in females from C3 to C7. The OPH in males was larger than in females at C3 to C6, but there was no difference at C7. The DIP and PTA were significantly greater in males than in females at C3, but there was no difference in the angle at C4-7. The PSTA was not statistically different between genders at C3, 4, 7, but this value in males was larger than females at C5, 6. The DIUP was significantly greater in males at C3, 4, 6, 7 but was non significant at C5.

CONCLUSIONS

The placement of cervical anterior transpedicular screws should be individualized for each patient and based on a detailed preoperative planning.

The management of vertebral artery injury in anterior cervical spine operation: a systematic review of published cases

PURPOSE

Anterior cervical spine operations (ACSO) are generally considered to be safe and effective, but the vertebral artery (VA) is at risk during the procedure. Because the consequences of VA injury can be catastrophic, properly managing a VA injury is very important. However, due to the rarity of these injuries, there is no agreed upon treatment strategy.

METHODS

Studies were identified for inclusion in the review via sensitive searches of electronic databases through 31 December 2011. All cases included in the review were qualitatively analyzed to explore the relationship between type of VA injury management and neurological complications.

RESULTS

Seventeen articles describing 39 cases of VA injury during ACSO were included in this study. Seven patients (17.9 %) had neurological complications followed by VA insufficiency. Two patients (5.1 %) had root damage due to ligation. One case (2.6 %) resulted in intraoperative death due to fatal bleeding. Delayed vascular complications were identified in nine (45.0 %) of the 20 patients that underwent only tamponade or hemostatic agent during the operation. Four patients underwent intraoperative endovascular treatment, and three of these patients had a cerebral infarction. All three patients who underwent clipping also had neurological complications. The five patients treated by direct repair did not have any complications.

CONCLUSION

Our review suggests the management of VA injury should be considered in order listed: (1) performing tamponade with a hemostatic agent, (2) direct repair, (3) postoperative endovascular procedures to prevent delayed complications. If tamponade fails to achieve proper hemostasis, additional procedures as endovascular embolization, clipping and ligation should be considered but carry the risk of neurological complications. Because of the limitations of this review, further studies are recommended with larger sample sizes.

Perioperative and delayed complications associated with the surgical treatment of cervical spondylotic myelopathy based on 302 patients from the AOSpine North America Cervical Spondylotic Myelopathy Study

OBJECT

Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy (CSM) are not clear. Appreciating these risks is important for patient counseling and quality improvement. The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM.

METHODS

Data from the AOSpine North America Cervical Spondylotic Myelopathy Study, a prospective, multicenter study, were analyzed. Outcomes data, including adverse events, were collected in a standardized manner and externally monitored. Rates of perioperative complications (within 30 days of surgery) and delayed complications (31 days to 2 years following surgery) were tabulated and stratified based on clinical factors.

RESULTS

The study enrolled 302 patients (mean age 57 years, range 29-86) years. Of 332 reported adverse events, 73 were classified as perioperative complications (25 major and 48 minor) in 47 patients (overall perioperative complication rate of 15.6%). The most common perioperative complications included minor cardiopulmonary events (3.0%), dysphagia (3.0%), and superficial wound infection (2.3%). Perioperative worsening of myelopathy was reported in 4 patients (1.3%). Based on 275 patients who completed 2 years of follow-up, there were 14 delayed complications (8 minor, 6 major) in 12 patients, for an overall delayed complication rate of 4.4%. Of patients treated with anterior-only (n = 176), posterior-only (n = 107), and combined anterior-posterior (n = 19) procedures, 11%, 19%, and 37%, respectively, had 1 or more perioperative complications. Compared with anterior-only approaches, posterior-only approaches had a higher rate of wound infection (0.6% vs 4.7%, p = 0.030). Dysphagia was more common with combined anterior-posterior procedures (21.1%) compared with anterior-only procedures (2.3%) or posterior-only procedures (0.9%) (p < 0.001). The incidence of C-5 radiculopathy was not associated with the surgical approach (p = 0.8). The occurrence of perioperative complications was associated with increased age (p = 0.006), combined anterior-posterior procedures (p = 0.016), increased operative time (p = 0.009), and increased operative blood loss (p = 0.005), but it was not associated with comorbidity score, body mass index, modified Japanese Orthopaedic Association score, smoking status, anterior-only versus posterior-only approach, or specific procedures. Multivariate analysis of factors associated with minor or major complications identified age (OR 1.029, 95% CI 1.002-1.057, p = 0.035) and operative time (OR 1.005, 95% CI 1.002-1.008, p = 0.001). Multivariate analysis of factors associated with major complications identified age (OR 1.054, 95% CI 1.015-1.094, p = 0.006) and combined anterior-posterior procedures (OR 5.297, 95% CI 1.626-17.256, p = 0.006).

CONCLUSIONS

For the surgical treatment of CSM, the vast majority of complications were treatable and without long-term impact. Multivariate factors associated with an increased risk of complications include greater age, increased operative time, and use of combined anterior-posterior procedures.

Ossification of the posterior longitudinal ligament: pathogenesis, management, and current surgical approaches. A review

Ossification of the posterior longitudinal ligament (OPLL) is an important cause of cervical myelopathy that results from bony ossification of the cervical or thoracic posterior longitudinal ligament (PLL). It has been estimated that nearly 25% of patients with cervical myelopathy will have features of OPLL. Patients commonly present in their mid-40s or 50s with clinical evidence of myelopathy. On MR and CT imaging, this can be seen as areas of ossification that commonly coalesce behind the cervical vertebral bodies, leading to direct ventral compression of the cord. While MR imaging will commonly demonstrate associated changes in the soft tissue, CT scanning will better define areas of ossification. This can also provide the clinician with evidence of possible dural ossification. The surgical management of OPLL remains a challenge to spine surgeons. Surgical alternatives include anterior, posterior, or circumferential decompression and/or stabilization. Anterior cervical stabilization options include cervical corpectomy or multilevel anterior cervical corpectomy and fusion, while posterior stabilization approaches include instrumented or noninstrumented fusion or laminoplasty. Each of these approaches has distinct advantages and disadvantages. While anterior approaches may provide more direct decompression and best improve myelopathy scores, there is soft-tissue morbidity associated with the anterior approach. Posterior approaches, including laminectomy and fusion and laminoplasty, may be well tolerated in older patients. However, there often is associated axial neck pain and less improvement in myelopathy scores. In this review, the authors discuss the epidemiology, imaging findings, and clinical presentation of OPLL. The authors additionally discuss the merits of the different surgical techniques in the management of this challenging disease.

Anterior approach for complex cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is a slowly progressive disease resulting from age-related degenerative changes in the spine that can lead to spinal cord dysfunction and significant functional disability. The degenerative changes and abnormal motion lead to vertebral body subluxation, osteophyte formation, ligamentum flavum hypertrophy, and spinal canal narrowing. Repetitive movement during normal cervical motion may result in microtrauma to the spinal cord. Disease extent and location dictate the choice of surgical approach. Anterior spinal decompression and instrumented fusion is successful in preventing CSM progression and has been shown to result in functional improvement in most patients.