Subaxial Cervical Spine Surgery Research Articles

Prospective Comparative Study of Dysphagia after Subaxial Cervical Spine Surgery: Cervical Spondylotic Myelopathy and Posterior Longitudinal Ligament Ossification

We prospectively investigated the postoperative dysphagia in cervical posterior longitudinal ligament ossification (C-OPLL) and cervical spondylotic myelopathy (CSM) to identify the risk factors of each disease and the incidence. A series of 55 cases with C-OPLL: 13 anterior decompression with fusion (ADF), 16 posterior decompression with fusion (PDF), and 26 laminoplasty (LAMP), and a series of 123 cases with CSM: 61 ADF, 5 PDF, and 57 LAMP, were included. Vertebral level, number of segments, approach, and with or without fusion, and pre and postoperative values of Bazaz dysphagia score, C2-7 lordotic angle (∠C2-7), cervical range of motion, O-C2 lordotic angle, cervical Japanese Orthopedic Association score, and visual analog scale for neck pain were investigated. New dysphagia was defined as an increase in the Bazaz dysphagia score by one grade or more than one year after surgery. New dysphagia occurred in 12 cases with C-OPLL; 6 with ADF (46.2%), 4 with PDF (25%), 2 with LAMP (7.7%), and in 19 cases with CSM; 15 with ADF (24.6%), 1 with PDF (20%), and 3 with LAMP (1.8%). There was no significant difference in the incidence between the two diseases. Multivariate analysis demonstrated that increased ∠C2-7 was a risk factor for both diseases.

The Difference of Sagittal Correction of Adult Subaxial Cervical Spine Surgery According to Age: A Retrospective Study.

ObjectiveAt present, the true sagittal alignment of the cervical spine is uncertain, resulting in no standard reference for subaxial cervical surgery. So, we aimed to explore the age difference of normal cervical sagittal alignment and to further investigate the mid‐and long‐term changes of sagittal alignment after subaxial cervical spine surgery.Materials and MethodsThis was a retrospective study and 1223 asymptomatic volunteers and 79 patients undergoing subaxial cervical spine surgery were retrospectively reviewed in total. Asymptomatic volunteers and patients were divided into six subgroups: 20–29, 30–39, 40–49, 50–59, 60–69 and ≥70 groups. The age difference and trend with age of cervical sagittal parameters of asymptomatic volunteers were assessed by cervical lateral radiography and analyzed by ANOVA test, and the regression equation of C2‐7 Cobb was established via multiple linear regression. Based on the C2‐7 Cobb regression equations of different ages, the theoretical value, deviation value, loss value of the C2‐7 Cobb, and JOA recovery rate of patients were calculated, and the correlation among the loss value, deviation value of the C2‐7 Cobb, and JOA recovery rate of the 79 patients was evaluated by Pearson correlation analysis.ResultsFor the asymptomatic volunteers, the C0‐2 Cobb decreased gradually with increasing age. The C2‐7 Cobb, C2‐7 SVA, T1S, NT, and TIA increased gradually with increasing age. The CBVA fluctuated with increasing age. T1S demonstrated a moderate correlation with C2‐7 Cobb (r = 0.60, p < 0.01); C0‐2 Cobb, C2‐7 SVA, CBVA, and TIA demonstrated a fair correlation with C2‐7 Cobb (r = −0.30, −0.33, 0.41, 0.40, p < 0.01); age demonstrated a poor correlation with C2‐7 Cobb (r = 0.19, p < 0.01). The regression equations of C2‐7 Cobb were established using C0‐2 Cobb, C2‐7 SVA, CBVA, and T1S. For the patients with subaxial cervical spine surgery, the loss of C2‐7 Cobb was moderately correlated with the deviation of C2‐7 Cobb (r = 0.33, p < 0.01).ConclusionThe age difference of cervical sagittal alignment was obvious, and the C2‐7 Cobb increased with age especially. The closer the postoperative C2‐7 Cobb was to the theoretical value of corresponding age, the smaller the loss of correction angle was, and the better the mid‐ and long‐term outcomes. The personalized sagittal reconstruction should be performed according to age difference for subaxial cervical spine surgery.

Incidence and local risk factors of infection after anterior sub-axial cervical spine surgery: retrospective database analysis of 4897 consecutive procedures.

The anterior cervical spine approach is safe and effective in many cervical spine pathologies. It is considered one of the most common approaches in spine surgery. Postoperative infections after anterior cervical surgery are rare but serious. This study is a retrospective database analysis. In this study, the incidence, and the local risk factors of postoperative infection after anterior-only sub-axial cervical spine surgery in a high-volume spine center were analyzed. The data of patients operated in a teaching hospital is electronically stored in a comprehensive medical database program. Postoperative infection after anterior cervical surgery from C2 to C7 was calculated and analyzed. In the study period, 4897 patients were operated. Twenty-four infections after a primary aseptic operation were detected. Independent local risk factors were estimated. Postoperative infection occurred in 24/4897 patients (0.49%). The incidence of infection after cervical trauma was 3% (7/229), after spinal cord injury 4.3% (2/46), with myelopathy 1.98% (11/556), and after revision surgery 1.25% (7/560). The incidence showed a significant increase (p = 0.00, 0.01, 0.02). In 14 of the postoperatively infected patients (58.3%) an oesophageal injury was diagnosed. Odds ratios (OR) with a confidence interval (CI) of 95% was calculated. Independent risk factors for the postoperative infections were: Cervical trauma (OR 8.59, 95% CI 3.52-20.93), revision surgery (OR 3.22, 95% CI 1.33-7.82), The presence of cervical myelopathy (OR 6.71, 95% CI 2.99-15.06), and spinal cord injury (OR 9.33, 95% CI 2.13-40.83). Postoperative infection after anterior cervical surgery is low (0.49%). In addition to the general risk factor for infection, the local risk factors are trauma, myelopathy, spinal cord injury, and revision surgeries. In the case of postoperative infection, an oesophageal injury should be excluded.

The diagnostic accuracy of MRI and non-enhanced CT for high-risk vertebral artery anatomy for the safety in subaxial anterior cervical spine surgery

The diagnostic accuracy of MRI and non-enhanced CT for high-risk vertebral artery anatomy for the safety in subaxial anterior cervical spine surgery

A Prospective Cohort Study of Dysphagia After Subaxial Cervical Spine Surgery.

Prospective observational cohort study. To prospectively examine dysphagia after subaxial cervical spine surgery. Although dysphagia after anterior cervical spine surgery is common and well-studied, it has rarely been examined in posterior subaxial cervical spine surgery. This study analyzed 191 consecutive patients (132 male, 59 female; mean age, 64.9 yrs) who underwent subaxial cervical spine surgery for degenerative disease and completed 1 year of follow-up. Anterior decompression with fusion (ADF) was performed in 87 patients, posterior decompression with fusion (PDF) in 21, and laminoplasty (LAMP) in 83. Dysphagia was evaluated by a self-administered questionnaire using the Bazaz dysphagia scale before, 6 months, and 1 year after surgery. Diagnosis, levels and number of operative segments, C2-7 lordotic angle (CL), O-C2 angle (OC2A), C2-7 range of motion (ROM), Japanese Orthopedic Association for cervical myelopathy (C-JOA) score, and neck pain visual analog scale (VAS) were examined. Thirty-two patients (16.8%) reported dysphagia before surgery. New dysphagia after surgery, defined as more than or equal to 1 grade worsening of the Bazaz score after surgery compared with the preoperative status, was observed in 38 patients (19.9%) at 6 months and 32 patients (16.8%) at 1 year. The incidence of new dysphagia at 1 year was 25.3% in the ADF group, 23.8% in the PDF group, and 6.0% in the LAMP group. Fusion surgery (ACDF or PDF) and increased CL after surgery were found as risk factors at 1 year in multivariate analysis; receiver operating characteristic analysis determined a postsurgical change in CL cutoff of 5°. Fusion surgery and increased CL after surgery were risk factors for development of dysphagia after subaxial cervical spine surgery. Cervical alignment change due to anterior and posterior fusion surgery can cause postoperative dysphagia.Level of Evidence: 3.

Comparison of TruView and King Vision video laryngoscopes in subaxial cervical spine injury: A randomized controlled trial.

Background: Airway management with cervical spine immobilization poses a particular challenge for intubation in the absence of neck extension and risks neurological damage in cases of unstable cervical spine injuries. Here, with manual inline stabilization (MILS) in patients with cervical spine injuries, we compared the safety/efficacy of intubation utilizing the TruView versus King Vision video laryngoscopes.Methods: This prospective, single-blind, comparative study was conducted over a 3-year period. The study population included 60 American Society of Anesthesiologists (ASA) Grade I-III patients, aged 18–65 years, who underwent subaxial cervical spine surgery utilizing two intubation techniques; TruView (TV) versus King Vision (KV). For both groups, relative intubation difficulty scores (IDS), total duration of intubation, hemodynamic changes, and other complications (e.g., soft-tissue injury and neurological deterioration) were recorded.Results: With MILS, patients in the KV group had statistically significant lower IDS (0.70 ± 1.02) and significantly shorter duration of intubation as compared to the TV group (1.67 ± 1.27) with MILS (P = 0.0010); notably, the glottic exposure was similar in both groups. The complication rate (e.g., soft-tissue injury) was lower for the KV group, but this was not statistically significant. Interestingly, no patient from either group exhibited increased neurological deterioration attributable to the method of intubation.Conclusion: King Vision has several advantages over TruView for intubating patients who have sustained cervical spine trauma. Nevertheless, both laryngoscopes afford comparable glottic views and safety profiles with similar alterations in hemodynamics.

Extraforaminal Vertebral Artery Anomalies and Their Associated Surgical Implications: An Epidemiologic and Anatomic Report on 1000 Patients

Extraforaminal vertebral anomalies involve entry at cervical transverse foramina other than at C6 and can appear with other anatomic variations along the V2 segment. Such unexpected vessel courses can have implications on surgical planning. We sought to evaluate the incidence of anomalous V2 segment entries, as well as their associations with vessel dominance, medialization, and C7 pedicle width. We conducted a retrospective study on 1000 consecutive computed tomography angiograms, documenting level and laterality of vessel of entry, as well as vertebral dominance patterns. Patients with rostral C4 anomalies were assessed for medialization. The pedicle widths ipsilateral to caudal C7 anomalies were compared with those of contralateral and matched controls. A total of 157 patients were identified with extraforaminal entries, with 25 having bilateral findings. The most common alternative entry was at C5 (70.3%), followed by C4 (17.6%) and C7 (11.5%). Among patients with unilateral anomalies, there was an increased representation of contralateral vertebral dominance, relative to ipsilateral dominance (79.6% vs 20.4%, P < 0.0001). Among anomalous C4 entries, vertebral medialization was seen along the right (35%) and left sides (23.1%) spanning C6-T1. Among C7 anomalous entries there was no statistical difference in pedicle width. Extraforaminal anomalies may be more frequent than previously reported and are important considerations during subaxial cervical spine surgery planning. Particular attention should be paid to the contralateral dominance pattern within this subgroup. In patients with anomalous V2 segment entries, adherence to the standard, anatomic landmarks remains desirable.

Improvements in Neck Pain and Disability Following C1-C2 Posterior Cervical Instrumentation and Fusion for Atlanto-Axial Osteoarthritis

Symptomatic Atlanto-axial (C1-2) osteoarthritis (AAOA) is a common phenomenon in elderly patients; however, there is a paucity of data on the effectiveness of posterior atlanto-axial fusion (PAAF) for this condition. To this end, here we assess changes in patient-reported outcomes and neck-related disability in adult patients undergoing PAAF for symptomatic C1-2 AAOA. In this retrospective study, the clinical records of consecutive patients with symptomatic AAOA who underwent PAAF between 2004 and 2017 were reviewed. Patient demographics, comorbidities, intraoperative and postoperative variables, and complication rates were collected. Neck Disability Index (NDI) scores were recorded at baseline and 6 weeks, 6 months, 1 year, and 2 years postoperatively. Forty-two patients (average age, 72.04 ± 8.56 years; 26.19% males) met the study's inclusion criteria. In this cohort, 19.04% had previous subaxial cervical spine surgery, 35.71% had a history of smoking (all had stopped smoking before surgery), and 11.90% had type II diabetes. At baseline, the majority of patients had a normal neurologic exam. The average preoperative NDI score was 26.88 ± 24.85, which improved to 10.59 ± 14.88 at the 1-year follow-up and 13.20 ± 14.96 at the 2-year follow-up (P=0.004). At baseline, 18% of the patients reported severe disability based on NDI score; this percentage decreased to 2% at 1 year and 0 at 2 years (P= 0.01). Importantly, a high percentage (11.90%) of patients had undergone previous subaxial cervical fusion for their pain due to a mistaken diagnosis for this condition, without symptom relief. In appropriately selected patients, PAAF may decrease neck pain and improve functional disability in patients with AAOA. Future prospective longitudinal studies are needed to corroborate these findings.

Sagittal profile of cervical and whole spine before and after surgery of subaxial cervical spine

Until recently, there was alack of information on sagittal axis parameters of the cervical spine, its relationship to the global sagittal axis of the spine, and their possible implications for long-term clinical outcomes in patients following subaxial cervical spine surgery. The aim of the authors is to provide an overview of the issue from available literature. The authors present acomplete overview of local radiological parameters of the sagittal axis of the cervical spine, an overview of radiological parameters of the total sagittal axis of the spine, and also spinopelvic parameters. Normative values &#8203;&#8203;of the majority of individual parameters are summarized. The authors discuss several topics such as: The possible effects of sagittal axis parameters on the clinical condition of an individual before surgery; furthermore, whether achange in sagittal parameters of the cervical and whole spine after subaxial cervical spine surgery can affect the clinical condition and postoperative patient satisfaction. Finally, the methodology of specific operations is discussed, including their ability to change the parameters of the sagittal axis of the spine. Short patient monitoring times and the predominant use of retrospective methodology are common drawbacks of most studies. Also, there are no clearly determined procedures and specifications for surgical correction of the sagittal axis of the cervical spine. As it turns out, multi-stage procedures are more appropriate to achieve changes of the cervical sagittal axis. It is also gradually becoming apparent that any local change of the cervical spine may affect the sagittal axis of the entire spine.

A Multicenter Review of Superior Laryngeal Nerve Injury Following Anterior Cervical Spine Surgery

Study Design:A retrospective multicenter case-series study; case report and review of the literature.Objective:The anatomy and function of the superior laryngeal nerve (SLN) are well described; however, the consequences of SLN injury remain variable and poorly defined. The prevalence of SLN injury as a consequence of cervical spine surgery is difficult to discern as its clinical manifestations are often inconstant and frequently of a subclinical degree. A multicenter study was performed to better delineate the risk factors, prevalence, and outcomes of SLN injury.Methods:A retrospective multicenter case-series study involving 21 high-volume surgical centers from the AO Spine North America Clinical Research Network. Medical records for 17 625 patients who received subaxial cervical spine surgery from 2005 to 2011 were reviewed to identify occurrence of 21 predefined treatment complications. Descriptive statistics were provided for baseline patient characteristics. A retrospective review of the neurosurgical literature on SLN injury was also performed.Results:A total of 8887 patients who underwent anterior cervical spine surgery at the participating institutions were screened, and 1 case of SLN palsy was identified. The prevalence ranged from 0% to 1.25% across all centers. The patient identified underwent a C4 corpectomy. The SLN injury was identified after the patient demonstrated difficulty swallowing postoperatively. He underwent placement of a percutaneous gastrostomy tube and his SLN palsy resolved by 6 weeks.Conclusions:This multicenter study demonstrates that identification of SLN injury occurs very infrequently. Symptomatic SLN injury is an exceedingly rare complication of anterior cervical spine surgery. The SLN is particularly vulnerable when exposing the more rostral levels of the cervical spine. Careful dissection and retraction of the longus coli may decrease the risk of SLN injury during anterior cervical surgery.

Rare Complications of Cervical Spine Surgery: Horner's Syndrome.

Study Design:A multicenter retrospective case series.Objective:Horner’s syndrome is a known complication of anterior cervical spinal surgery, but it is rarely encountered in clinical practice. To better understand the incidence, risks, and neurologic outcomes associated with Horner’s syndrome, a multicenter study was performed to review a large collective experience with this rare complication.Methods:We conducted a retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network. Medical records for 17 625 patients who received subaxial cervical spine surgery from 2005 to 2011 were reviewed to identify occurrence of 21 predefined treatment complications. Descriptive statistics were provided for baseline patient characteristics. Paired t test was used to analyze changes in clinical outcomes at follow-up compared to preoperative status.Results:In total, 8887 patients who underwent anterior cervical spine surgery at the participating institutions were screened. Postoperative Horner’s syndrome was identified in 5 (0.06%) patients. All patients experienced the complication following anterior cervical discectomy and fusion. The sympathetic trunk appeared to be more vulnerable when operating on midcervical levels (C5, C6), and most patients experienced at least a partial recovery without further treatment.Conclusions:This collective experience suggests that Horner’s syndrome is an exceedingly rare complication following anterior cervical spine surgery. Injury to the sympathetic trunk may be limited by maintaining a midline surgical trajectory when possible, and performing careful dissection and retraction of the longus colli muscle when lateral exposure is necessary, especially at caudal cervical levels.

Screw-related complications in the subaxial cervical spine with the use of lateral mass versus cervical pedicle screws

Lateral mass screws (LMS) have been used extensively with a low complication rate in the subaxial spine. Recently, cervical pedicle screws (CPS) have been introduced, and are thought to provide more optimal stabilization of the subaxial spine in certain circumstances. However, because of the concern for neurovascular injury, the routine use of CPS in this location remains controversial. Despite this controversy, however, there are no articles directly comparing screw-related complications of each procedure in the subaxial cervical spine. The purpose of this study was to evaluate screw-related complications of LMS and CPS in the subaxial cervical spine. A PubMed/MEDLINE and Cochrane Collaboration Library search was executed, using the key words "lateral mass screw" and "cervical pedicle screw." Clinical studies evaluating surgical procedures of the subaxial cervical spine in which either LMS or CPS were used and complications were reported were included. Studies in which the number of patients who had subaxial cervical spine surgery and the number of screws placed from C-3 to C-7 could not be specified were excluded. Data on screw-related complications of each study were recorded and compared. Ten studies of LMS and 12 studies of CPS were included in the analysis. Vertebral artery injuries were slightly but statistically significantly higher with the use of CPS relative to LMS in the subaxial cervical spine. Although the use of LMS was associated with a higher rate of screw loosening, screw pullout, loss of reduction, pseudarthrosis, and revision surgery, this finding was not statistically significant. Based on the available literature, it appears that perioperative neurological and late biomechanical complication rates, including pseudarthrosis, are similarly low for both LMS and CPS techniques. In contrast, vertebral artery injuries, although statistically significantly more common when using CPS, are extremely rare with both techniques, which may justify their nonroutine use in select cases. Given the paucity of well-designed studies available, this recommendation may be a reflection of deficiencies in the available studies. Surgeons using either technique should have intimate knowledge of cervical anatomy and an adequate preoperative evaluation for each patient, with the final selection based on individual case requirements and anatomical limitations.