Clinically relevant anatomy of recurrent laryngeal nerve

Incidence, Risk Factors, and Outcomes of Recurrent Laryngeal Nerve Injury and Dysphonia Following Anterior Cervical Spine Surgery: A Systematic Review and Meta-Analysis

Anterior cervical spine surgery (ACSS) is an effective treatment for various cervical spine conditions but carries a risk of recurrent laryngeal nerve (RLN) injury and dysphonia. This systematic review and meta-analysis aimed to evaluate the incidence of these complications and their associated risk factors. An analysis of 17 studies involving 5,706 patients revealed a pooled RLN injury incidence of 3.41% and a dysphonia incidence of 2.5%. Prolonged surgeries exceeding two hours and multilevel procedures were associated with higher risks, while implant material demonstrated minimal impact. These findings highlight the importance of surgical planning to mitigate RLN injury risk and improve patient outcomes in ACSS.

A vocal cord palsy caused by the uterine cancer metastatic tumor in the mediastinum revealed in a patient with a thyroid lesion: a case report and review of the literature

BACKGROUND

The main cause of vocal cord palsy (VCP) is idiopathic impairment of the recurrent laryngeal nerve (RLN). However, solid tumors along the pathway of the RLN can also impact the nerve's function. We presented a patient with a thyroid lesion and VCP due to a bulky metastatic mass (uterine cancer) on the aortic arch field in the mediastinum. The report aims to show the significance of comorbid tumors in thyroid pathology and the importance of additional diagnostic methods in avoiding unnecessary surgeries. A patient's lifetime and the outcome of the disease were also presented.

CASE PRESENTATION

A 58-year-old Ukrainian woman with a hoarse voice, intermittent dry cough, and weakness was presented to an endocrine surgeon. Thyroid pathology included signs of hypothyroidism treated with Thyroxine 112.5 µg and a nodule in the left lobe. The lesion is located on the posterior aspect of the lobe, which could probably be a cause of RLN involvement. Fine needle aspiration biopsy (FNAB) was performed twice with Bethesda category 2 result. Fibrolaryngoscopy (FLS) revealed the median position of the left vocal cord. Idiopathic, laryngeal, and thyroid causes of the VCP were excluded. Additionally, the patient displayed her anamnesis of the endometrial clear cell carcinoma following hysterectomy, external beam radiation therapy, and chemotherapy. The mediastinal metastasis was revealed sixteen years later. A chest computed tomography (CT) with intravenous contrast was done. A bulky tumor was found right under the aortic arch. Subsequently, the voice complaints reduced significantly after 4 chemotherapy courses. Cancer progression had led to the appearance of lymph node metastases on the supraclavicular region. Following six months the 60-year-old patient had passed away.

CONCLUSION

A history of the disease should always be kept in mind when assessing a patient's complaints. VCP in case of thyroid pathology and previous secondary malignancy may be caused by metastatic tumor anywhere along the RLN pathway. Such a rare case shows the importance of additional methods of examination which may avoid unnecessary thyroid surgeries.

Delayed Bilateral Vocal Cord Paralysis Following Cervical Spine Trauma

Bilateral vocal cord paralysis is a potentially life-threatening condition, depending on the position in which the vocal cords are paralyzed. When the vocal cords are fixed in adduction, patients develop respiratory distress, inspiratory stridor, aspiration, and minimal phonation deficits. This condition can result from acute injuries to the right and left recurrent laryngeal nerves, or from chronic bilateral recurrent laryngeal nerve palsy. The clinical presentation is variable with such nerve injuries. Traumatic injuries to the cervical spine are an uncommon cause of this condition. In this report, we describe a patient who developed progressive respiratory distress, inspiratory stridor, and dysphagia to liquids several weeks after suffering major trauma to the head and neck. Laryngoscopy revealed immobile bilateral vocal cords fixed in the paramedian position, resulting in severe airway obstruction that warranted an emergency tracheostomy.

A scoping review of the methods used to capture dysphagia after anterior cervical discectomy and fusion: the need for a paradigm shift

OBJECTIVE

Dysphagia is the most commonly reported complication of annterior cervical discectomy and fusion (ACDF) surgery. However, the incidence of dysphagia post-ACDF varies widely-partly attributable to differing outcome measures used to capture dysphagia. Our objective was to conduct a scoping review of the literature to quantify which dysphagia outcome measures have been employed post-ACDF and examine trends by study design, year, and location.

METHODS

After removing duplicates, 2396 abstracts were screened for inclusion. A total of 480 studies were eligible for full-text review. After applying exclusion criteria, data was extracted from 280 studies. We extracted the dysphagia outcome measure(s), study design (prospective vs retrospective), year, and location (country). Approximately 10% of studies were repeated for intra-rater agreement.

RESULTS

In total, 317 dysphagia outcome measures were reported in 280 studies (primarily retrospective-63%). The largest proportion of outcome measures were categorized as "unvalidated patient-reported outcome measures" (46%), largely driven by use of the popular Bazaz scale. The next most common categories were "insufficient detail" and "validated patient-reported outcome measures" (both 16%) followed by "chart review/database" (13%) and instrumental assessment (7%). Studies examining dysphagia post-ACDF steadily increased over the years and the use of validated measures increased in the past 10 years.

CONCLUSIONS

This scoping review of the literature highlights that nearly half of the ACDF dysphagia literature relies on unvalidated patient-reported outcome measures. The current understanding of the mechanism, timeline, and presentation of dysphagia post-ACDF are likely limited due to the metrics that are most commonly reported in the literature.

Etiology and presenting features of vocal cord paralysis: changing trends over the last two decades

Background

The study was performed to evaluate the changing trends in etiology and presenting features of vocal cord paralysis (VCP) from March 1998 to March 2020.

Methods

Patient’s record collected from hospital database and divided into two groups, from March 1998 to March 2009 and from April 2009 to March 2020, to evaluate the changing trends in etiology and presenting features.

Results

Total of 711 VCP patients, 80.3% with unilateral (UVCP) and 19.7% with bilateral vocal cord paralysis (BVCP) included. The commonest etiology was non-surgical (57.1%) for UVCP and surgical (55.7%) for BVCP. The commonest surgical etiology was thyroid and parathyroid surgery for both UVCP (16.6%) and BVCP (38.5%). The commonest non-surgical etiology was idiopathic for UVCP (23.1%) and malignancies for BVCP (13.6%). There was increase in surgical etiology for both UVCP (39.3 to 45.3%) and BVCP (51.2 to 57.7%), and decrease in non-surgical etiology for both UVCP (60.7 to 54.6%) and BVCP (48.8 to 42.3%). The change in voice was most common presenting features for both UVCP (69.2%) and BVCP (92.8%). The frequency of the presenting features was comparable, with decrease in the duration of symptom onset over the time period.

Conclusion

The most common etiology for UVCP was idiopathic, and for BVCP was thyroid and parathyroid surgery. For both, UVCP and BVCP there was increasing trend for surgical and decreasing trend for non-surgical etiology. The change in voice was the most common presenting complain, with decrease in duration of symptom onset over time period.

Neonatal Airway Abnormalities

Neonatal airway abnormalities are commonly encountered by the neonatologist, general pediatrician, maternal fetal medicine specialist, and otolaryngologist. This review article discusses common and rare anomalies that may be encountered, along with discussion of embryology, workup, and treatment. This article aims to provide a broad overview of neonatal airway anomalies to arm those caring for these children with a broad differential diagnosis and basic knowledge of how to manage basic and complex presentations.

Critical analysis of the evaluation of postoperative dysphagia following an anterior cervical discectomy and fusion

BACKGROUND AND PURPOSE

Postoperative dysphagia is a known complication of anterior cervical discectomy and fusion (ACDF) with reported incidences ranging from 1 to 79%. No standardized guidelines exist for spine surgeons to evaluate postoperative dysphagia after ACDF. A systematic method may be beneficial in distinguishing transient postoperative dysphagia secondary to intubation from those with postoperative complications. This study evaluates the causes, recognition, and clinical evaluation of postoperative dysphagia following ACDF.

METHODS

International classification of disease (ICD) and current procedural terminology (CPT) codes were used to identify ACDF patients and compared to anterior lumbar discectomy and fusion (ALDF), serving as a control group, between the years 2015-2019 and those diagnosed with dysphagia within 1 year. Demographics, operative details, and clinical evaluation were reviewed. Exclusion criteria included history of head and neck procedures, cancer, stroke, radiation, and trauma.

RESULTS

One hundred thirty-one ACDF and 93 ALDF patients met inclusion criteria. Twenty-seven (20.6%) ACDF patients were diagnosed with dysphagia within 1 year. Less than half of the dysphagia patients had the word "dysphagia" documented in their 1-month spine surgeon follow up visit. Only 66% of dysphagia patients had specialist evaluation and one third of those patients were referred by their surgeon. Only six patients received diagnostic barium swallow evaluations.

CONCLUSION

Postoperative dysphagia risk increases in ACDF compared to ALDF, likely due to underlying anatomy. Postoperative dysphagia symptoms are not effectively documented by spine surgeons and as a result underevaluated by dysphagia specialists. Patients may benefit from more extensive pre- and post-operative screening, evaluation, and referral regarding dysphagia symptoms following ACDF.

Recurrent Laryngeal Nerve Injury Near the Nerve Entry Point in Total Endoscopic Thyroidectomy: A Retrospective Cohort Study

Background

Recurrent laryngeal nerve injury (RLNI) still occurs in total endoscopic thyroidectomy (TET) by using intraoperative neuromonitoring (IONM). As the region where most injuries occur, more attention should be paid to RLNI near the nerve entry point (NEP) in TET.

Materials and Methods

This cohort study collected retrospectively data from 415 patients who underwent TET between February 2012 and December 2019. The functions of the recurrent laryngeal nerve (RLN) in TET were recorded by IONM. The patients with RLNI near the NEP were followed up by laryngoscopies. The demographic and clinical characteristics, the mechanisms of RLNI, and the outcomes of RLNI were recorded and analyzed.

Results

There were a total of 444 at-risk nerves in 405 patients were analyzed. The incidence of RLNI near the NEP was 7.9%. RLNs with extralaryngeal branches were more likely to be injured near the NEP (P = 0.037). The incidences of different types of RLNI, in order of frequency, were 68.8% for thermal injury (n = 22), 28.1% for traction/compression injury (n = 9), and 3.1% for transverse injury (n = 1). A total of 93.8% (n = 30) of RLNI patients had complete recovery of vocal cord activity function.

Conclusion

The extralaryngeal branch was a risk factor for RLNI near the NEP in TET. Thermal injury caused by an ultrasonic scalpel was the most common cause of RLNI near the NEP. Most RLNIs near the NEP would eventually recover.

Palpation of the Respiratory System in Osteopathic Manual Medicine: From the Trachea to the Lungs

There is a lack of published literature in osteopathic manual medicine on how to perform palpation of the lower respiratory tree such as the trachea, main bronchi, and lungs. Several authors have studied the osteopathic effect and respiratory response of palpation but have failed to demonstrate how to perform palpation of the visceral areas involved in breathing, either in the context of a clinical trial or as a case report. This paper reviews the innervation of these anatomical areas, the mechano-metabolic weight of the passage of fluids and air in the respiratory tract, the anatomical topography, and the movements involved in respiration. Drawing from current knowledge, this article illustrates, for the first time, how to place the hands for an effective osteopathic assessment of the tracheal, bronchial, and pulmonary structures. Understanding how to perform palpation of the lower areas is a fundamental tool in the clinic and potential therapy in osteopathic manual medicine.

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.

Causes of Vocal Fold Paralysis

BACKGROUND

Vocal fold paralysis (VFP) can result from a variety of diseases or surgeries and has various causes. This study determined concurrent etiologies in patients who were treated in a teaching hospital (tertiary medical center).

METHODS

A retrospective review of medical records of patients with VFP from September 2010 to December 2019 was performed to determine the etiology. Patients with laryngeal/hypopharyngeal malignancies, those with incomplete examination and follow-up data were excluded from the study. During the follow-ups, cases involving recovery were also excluded.

RESULTS

One hundred and ninety-four patients with a determined etiology were included: 113 males and 81 females. Unilateral VFP was present in 178 patients, and 16 presented with bilateral VFP. The causes of unilateral VFP were surgical for 61.3%, neoplastic for 17.5%, idiopathic for 10.3%, traumatic for 1.5%, central for 4.7%, cardiovascular for 2%, radiation-induced for 1.5%, and inflammatory for 1%. Thyroidectomy was the most common surgery for unilateral VFP and was the cause for 54 patients. Lung cancer was responsible for 15 cases and was the most common neoplastic etiology of unilateral VFP. For those who presented with bilateral VFP, surgery was the most common cause and accounted for 56.3% of the incidences. In terms of gender, surgery was the most common cause for both sexes, accounting for 62 of 113 male patients and 57 of 81 female patients. Four cases recovered during the follow-ups and these were excluded.

CONCLUSION

Surgery and in particular, thyroidectomy, was the most common cause of VFP for these series. Central nervous system disorders were the cause of VFP (4.5%). Central nervous system disorders, especially cerebrovascular accidents that induced VFP, could not be neglected. Radiation-induced cranial nerve paralysis in the head and neck cancer was possible causes. The percentage for the causes of unilateral VFP, surgery increased and the percentage for neoplasm decreased for Taiwan.

Anatomical Variations of the Recurrent Laryngeal Nerve and Implications for Injury Prevention during Surgical Procedures of the Neck

Accurate knowledge of anatomical variations of the recurrent laryngeal nerve (RLN) provides information to prevent inadvertent intraoperative injury and ultimately guide best clinical and surgical practices. The present study aims to assess the potential anatomical variability of RLN pertaining to its course, branching pattern, and relationship to the inferior thyroid artery, which makes it vulnerable during surgical procedures of the neck. Fifty-five formalin-fixed cadavers were carefully dissected and examined, with the course of the RLN carefully evaluated and documented bilaterally. Our findings indicate that extra-laryngeal branches coming off the RLN on both the right and left side innervate the esophagus, trachea, and mainly intrinsic laryngeal muscles. On the right side, 89.1% of the cadavers demonstrated 2–5 extra-laryngeal branches. On the left, 74.6% of the cadavers demonstrated 2–3 extra-laryngeal branches. In relation to the inferior thyroid artery (ITA), 67.9% of right RLNs were located anteriorly, while 32.1% were located posteriorly. On the other hand, 32.1% of left RLNs were anterior to the ITA, while 67.9% were related posteriorly. On both sides, 3–5% of RLN crossed in between the branches of the ITA. Anatomical consideration of the variations in the course, branching pattern, and relationship of the RLNs is essential to minimize complications associated with surgical procedures of the neck, especially thyroidectomy and anterior cervical discectomy and fusion (ACDF) surgery. The information gained in this study emphasizes the need to preferentially utilize left-sided approaches for ACDF surgery whenever possible.

Recurrent Laryngeal Nerve Morbidity: Lessons from Endoscopic via Bilateral Areola and Open Thyroidectomy Technique

BACKGROUND AND AIM

Elucidating the mechanism of recurrent laryngeal nerve (RLN) injuries through intraoperative electromyographic (EMG) and laryngeal examination approaches may deepen our knowledge regarding its prevention strategies. To date, no studies have been reported on the mechanism of RLN injury caused by endoscopic thyroidectomy via bilateral areola approach (ETBAA).

METHODS

Both intraoperative EMG profiles and postoperative laryngeal examination were used to investigate the mechanisms of RLN injury and compare the safety aspects between ETBAA and open thyroidectomy approach (OTA).

RESULTS

This study examined 1420 nerves at risk. The mean follow-up period was 17 ± 4 (range 6-48) months. The incidence of vocal cord paralysis was 4.1% (59/1420). The number of cases with decreased EMG signals and vocal cord palsy was higher in ETBAA group than in OTA group (P < 0.05). The left RLNs in ETBAA group were at higher risk compared to the right nerves.

CONCLUSIONS

The results of the current study indicate that ETBAA exhibits higher risk of RLN injury. The topic includes a video.

Right- Versus Left-sided Exposures of the Recurrent Laryngeal Nerve and Considerations of Cervical Spinal Surgical Corridor: A Fresh-Cadaveric Surgical Anatomy of RLN Pertinent to Spine

STUDY DESIGN

Cadaveric study on fresh unprocessed, nonpreserved, undyed specimens which have not previously been reported.

OBJECTIVE

We aimed to perform surgically relevant exposures of the anterior cervical spine with particular attention to observing the potential vulnerabilities of the RLN on right and left.

SUMMARY OF BACKGROUND DATA

Vulnerability of the RLN in the anterior cervical spine approach on the right versus left is the subject of ongoing debate. Although most cadaveric studies focus on course variations, structural relations of RLN, they have been done in preserved (fixed) cadavers without relevance to the needs of spinal exposure.

METHODS

Twelve fresh undyed cadavers had extensive layer by layer dissections by 2 surgeons (one with extensive experience as anatomy dissector). Both sides were explored for vulnerability during cervical spinal procedures. Each dissection was carried out in a phased approach and deliberately explored beyond what can be afforded in live surgery to allow the reader to conceptualize a better view of the structures.

RESULTS

In all specimens, we consistently demonstrated that the right surgical corridor involved manipulation of the nerve and its branches especially below C5 to achieve optimum midline access: in the right corridor, the RLN is on its oblique course to the tracheoesophageal groove. On the left, RLN is already in the tracheoesophageal groove and out of the surgical field involving minimal direct mobilization of the nerve.

CONCLUSION

RLN surgical anatomy photographed here is novel in using fresh unprocessed cadaveric specimens which has previously not been reported.Right surgical corridor, below C5, involves retraction/manipulation of RLN for achieving optimum spinal midline access, highlighting potential surgical vulnerability of right RLN.

LEVEL OF EVIDENCE

3.

Anterior Cervical Discectomy and Fusion combined with thyroid gland surgery, a tailored case and literature review

Background

Nowadays, Anterior Cervical Discectomy and Fusion (ACDF) is considered a routine procedure. However, unexpected difficulties do occasionally arise, especially when anterior neck pathologies or anatomical variations are encountered. In such cases, proactive thinking will allow surgeons to tailor appropriately their approach and eliminate surgical risks.

Case presentation

We present the case of a 50-year-old male patient suffering from left upper limb radiculopathy that underwent a C7-T1 ACDF combined with a hemithyroidectomy. Excision of the right thyroid lobe was offered to the patient because of a goiter found during the preoperative work-up. Furthermore, the hemithyroidectomy provided a wide surgical field so the ACDF performed without excreting excessive traction to the adjacent neck structures.

Conclusions

The patient had an uncomplicated post-operative. To our knowledge this is the first report of a planned hemithyroidectomy being carried out as the first step towards an ACDF procedure.

Comparative study of three types of lymphadenectomy along the left recurrent laryngeal nerve by minimally invasive esophagectomy

Background

The objective of this study was to compare three kinds of lymphadenectomy methods along the recurrent laryngeal nerve (RLN) and assess the safety and effectiveness of the new method.

Methods

A total of 194 patients with esophageal cancer who underwent minimally invasive esophagectomy (MIE) at our institution from May 2013 to May 2017 were analyzed retrospectively. According to the method of lymphadenectomy along the left RLN, the patients were divided into three groups: 75 cases underwent the conventional method (A group), 80 cases the skeletonized method (B group) and 39 cases the modified Bascule method (C group). The number of dissected lymph nodes and surgical outcomes were recorded and compared to identify differences among the three groups.

Results

The frequency of metastasis to the LRLN lymph node was 18.6% among all patients, and 12%, 20% and 28% in groups A, B and C, respectively. The number of harvested lymph nodes (total/chest/LRLN/LRLN+) in group B and group C were significantly greater than that of group A, but not significant between group B and group C. The hoarseness rate in group C was 15.4%, which was lower than the rate in group B (21.3%) and higher than the rate in group A (13.3%), but there was no statistical significance.

Conclusions

The new method for lymphadenectomy along the left RLN during MIE in the semi‐prone position is safe and reliable. It provides sufficient lymph node dissection along the left RLN.

Right Versus Left Approach to Anterior Cervical Discectomy and Fusion: An Anatomic Versus Historic Debate

The debate over the influence approach sidedness has on the risk of recurrent laryngeal nerve palsy (RLNP) following anterior cervical discectomy and fusion (ACDF) has its origins with the introduction of the procedure for radicular pain in the 1950s. The recurrent laryngeal nerves follow disparate courses in the lower neck secondary to differences in embryogenesis. Because of these differences, some authors believe a right-sided approach increases the risk of RLNP. However, modern surgical series have not shown a clear risk of RLNP with a right- versus left-sided approach. By looking at the historical context surrounding the introduction of ACDF, we propose the dogmatic view of an increased risk of RLNP with a right-sided approach likely arose from a combination of theoretical anatomic risk and the early surgical experience of a pioneer of the procedure.

Cervical spondylotic myelopathy: A two decade experience

Context Cervical myelopathy occurs as a result of compression of the cervical spinal cord. Symptomatology includes, but is not limited to, pain, weakness, paresthesias, or gait/balance difficulties. Objective To present a two-decade experience with the management of cervical myelopathy. Methods Literature was reviewed to provide current guidelines for management as well as accompanying clinical presentations. Results Surgical decompression, if necessary, may be achieved from either an anterior, a posterior, or a combined anterior-posterior (AP) approach. The indications for each approach, as well as the surgical techniques, are described. Conclusion Several etiologies may lead to cord compression and cervical myelopathy. The best vector of approach with regard to anterior versus posterior surgical intervention is still under investigation. Regardless, management via surgical decompression has been demonstrated repeatedly to improve the CSM patients' quality of life.

Olfactory-ensheathing cells promote physiological repair of injured recurrent laryngeal nerves and functional recovery of glottises in dogs

The aim of this study was to investigate whether the transplantation of olfactory-ensheathing cells (OECs) could physiologically repair severely injured recurrent laryngeal nerve (RLN) in dogs. Adult Beagle dogs were surgically introduced with a 10-mm defect in the left RLN and transplanted with a nerve guide (NEUROLAC) containing dog olfactory mucosa-olfactory-ensheathing cells (OM-OECs) in matrigel. The effects of OM-OECs on the morphology, histology, and electrophysiology of the injured RLNs, glottis movement, and voice acoustics were comparatively studied. Two months after transplantation, the normal dogs (group N) had intact left RLNs that contained axons well organized as bundles, transmitted action potentials of high amplitudes without latent phases, and modulated glottis movement to produce normal voices. The RLN-damaged dogs transplanted with OM-OECs (group CTT) had pieces of nerves regenerated in the place of the defects, which contained fewer axons scattered in the internal nerve membrane and wrapped peripherally by the connective tissue, prevented the distal trunk of the defected RLN from shrinking, transmitted action potentials of lower amplitudes with latent phases, and modulated a slightly impaired glottis movement to produce voices with slight differences compared to the N dogs. The RLN-damaged dogs without OM-OECs (group NC) had no nerves generated at the defective or the damaged area, leading to a shrinkage in the enervated distal nerve trunks; a blockage in nerve pulse transit; a paralysis of the left vocal cords; an impaired glottis movement; and abnormal voices. Transplantation of OM-OECs promoted nerve regeneration, and the recoveries of glottises and voices in dogs with RLN injury.

Risk factors and preventative measures of early and persistent dysphagia after anterior cervical spine surgery: a systematic review

PURPOSE

To conduct a systematic review of literature to determine risk factors and preventative measures of early and persistent dysphagia after anterior cervical spine surgery (ACSS).

METHODS

On March 2017, we searched the database PubMed, Medline, EMBASE, the Cochrane library, Clinical key, Springer link and Wiley Online Library without time restriction using the term 'dysphagia', 'swallowing disorders', and 'anterior cervical spine surgery'. Selected papers were examined for the level of evidence by published guidelines as level I, level II, level III, level IV studies. We investigated risk factors and preventative measures of early or persistent dysphagia after ACSS from these papers.

RESULTS

The initial search yielded 515 citations. Fifty-nine of these studies met the inclusion and exclusion criteria. Three of them were level I evidence studies, 29 were level II evidence studies, 22 were level III evidence studies, and 3 were level IV evidence studies. Preventable risk factors included prolonged operative time, use of rhBMP, endotracheal tube cuff pressure, cervical plate type and position, dC2-C7 angle, psychiatric factors, tobacco usage, prevertebral soft tissue swelling, SLN or RLN palsy or injury of branches. Preventative measures included preoperative tracheal traction exercise, maintaining endotracheal tube cuff pressure at 20 mm Hg, avoiding routine use of rhBMP-2, use of zero-profile implant, use of Zephir plate, use of new cervical retractor, steroid application, avoiding prolonged operating time, avoiding overenlargement of cervical lordosis, decreasing surgical levels, ensuring knowledge of anatomy of superior laryngeal nerve and recurrent laryngeal nerve, to comfort always, patients quitting smoking and doctors ensuring improved skills. Unpreventable risk factors included age, gender, multilevel surgery, revision surgery, duration of preexisting pain, BMI, blood loss, upper levels, preoperative comorbidities and surgical type.

CONCLUSION

Adequate preoperative preparation of the patients including preoperative tracheal traction exercise and quitting smoking, proper preventative measures during surgery including maintaining endotracheal tube cuff pressure at 20 mm Hg, avoiding routine use of rhBMP-2, use of zero-profile implant, use of Zephir plate, use of new cervical retractor, steroid application, avoiding prolonged operating time, avoiding overenlargement of cervical lordosis and decreasing surgical levels, doctors ensuring knowledge of anatomy, improved surgical techniques and to comfort always are essential for preventing early and persistent dysphagia after ACSS.

Influence of prevertebral soft tissue swelling on dysphagia after anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage

BACKGROUND

Postoperative oropharyngeal complications such as dysphagia after anterior cervical spine surgery are some of the least discussed surgery-related complications. The purpose of this retrospective study is to investigate the incidence and possible risk factors for 30-day postoperative dysphagia after anterior cervical discectomy and fusion (ACDF).

MATERIALS AND METHODS

This study included 152 consecutive patients who underwent 1- or 2-level ACDF using a rectangular titanium stand-alone cage in our institutes. Surgery-related dysphagia early after surgery was analyzed based on hospital charts. Radiological evaluation of prevertebral soft tissue swelling (PSTS) was performed by comparing plain lateral radiographs of the cervical spine before surgery with those after surgery. The percentage of PSTS (%PSTS) was defined by retropharyngeal soft tissue diameter divided by vertebral diameter. Positive %PSTS was determined when %PSTS exceeded its mean + 2 standard deviations.

RESULTS

Twelve patients (7.9%) demonstrated prolonged symptoms of dysphagia within 30-day postoperatively. All patients eventually demonstrated satisfactory or acceptable recovery late after surgery, except one case of hypoglossal nerve palsy. %PSTS was significantly highest early after surgery and returned to presurgical levels within 30 days after surgery. Statistical analysis suggested that the positive %PSTS at C3 or C4 level early after surgery was significantly associated with the occurrence of postoperative dysphagia.

CONCLUSIONS

Although the possible reasons for postoperative dysphagia may not only be multifactorial but also be highly surgeon-dependent, such a complication is still underestimated and needs to be carefully resolved. %PSTS appeared to be easy and reliable index to judge the possible risk of postoperative dysphagia.

Aortic arch compliance and idiopathic unilateral vocal fold paralysis

Unilateral vocal fold paralysis (UVP) occurs related to recurrent laryngeal nerve (RLN) impairment associated with impaired swallowing, voice production, and breathing functions. The majority of UVP cases occur subsequent to surgical intervention with approximately 12-42% having no known cause for the disease (i.e., idiopathic). Approximately two-thirds of those with UVP exhibit left-sided injury with the average onset at ≥50 yr of age in those diagnosed as idiopathic. Given the association between the RLN and the subclavian and aortic arch vessels, we hypothesized that changes in vascular tissues would result in increased aortic compliance in patients with idiopathic left-sided UVP compared with those without UVP. Gated MRI data enabled aortic arch diameter measures normalized to blood pressure across the cardiac cycles to derive aortic arch compliance. Compliance was compared between individuals with left-sided idiopathic UVP and age- and sex-matched normal controls. Three-way factorial ANOVA test showed that aortic arch compliance (P = 0.02) and aortic arch diameter change in one cardiac cycle (P = 0.04) are significantly higher in patients with idiopathic left-sided UVP compared with the controls. As previously demonstrated by other literature, our finding confirmed that compliance decreases with age (P < 0.0001) in both healthy individuals and patients with idiopathic UVP. Future studies will investigate parameters of aortic compliance change as a potential contributor to the onset of left-sided UVP.NEW & NOTEWORTHY Unilateral vocal fold paralysis results from impaired function of the recurrent laryngeal nerve (RLN) impacting breathing, swallowing, and voice production. A large proportion of adults suffering from this disorder have an idiopathic etiology (i.e., unknown cause). The current study determined that individuals diagnosed with left-sided idiopathic vocal fold paralysis exhibited significantly greater compliance than age- and sex-matched controls. These seminal findings suggest a link between aortic arch compliance levels and RLN function.

Anatomic Relationship Between Right Recurrent Laryngeal Nerve and Cervical Fascia and Its Application Significance in Anterior Cervical Spine Surgical Approach

STUDY DESIGN

An anatomic study of anterior cervical dissection of 42 embalmed cadavers.

OBJECTIVE

The aim was to study the anatomic relationship between recurrent laryngeal nerve (RLN) and cervical fascia combined with the requirements in anterior cervical spine surgery (ACSS).

SUMMARY OF BACKGROUND DATA

There has been no systematic research about how to avoid RLN injury in anterior cervical spine surgical approach from the aspect of the anatomic relationship between RLN and cervical fascia.

METHODS

Forty-two adult cadavers were dissected to observe the relationships between RLN and different cervical fascia layers.

RESULTS

RLN pierced out the alar fascia from the inner edge of the carotid sheath in all cases, and the piercing position in 22 cases (52.4%) was located at the lower segment of T1. The enter point into visceral fascia of RLN was located at C7-T1 in 25 cases (59.5%). The middle layer of deep cervical fascia exhibited the most stable anatomic relationship with RLN at the carotid sheath confluence site. Pulling visceral sheath leftwards would significantly increase the RLN tension.

CONCLUSION

Using the close and stable relationship between RLN and cervical fascia could help to avoid RLN injury in anterior cervical spine surgical approach.

LEVEL OF EVIDENCE

4.

Changes in Swallowing After Anterior Cervical Discectomy and Fusion With Instrumentation: A Presurgical Versus Postsurgical Videofluoroscopic Comparison

PURPOSE

The purpose of this study was to explore the impact of anterior cervical discectomy and fusion (ACDF) with anterior instrumentation on swallowing function and physiology as measured on videofluoroscopic swallowing studies.

METHOD

We retrospectively analyzed both functional measures (penetration-aspiration, residue) and physiological/anatomical measures (hyoid excursion, posterior pharyngeal wall thickness) in a series of 17 patients (8 men, 9 women, mean age 54 years). These measures were extracted from calibrated 5-ml boluses of thin radio-opaque liquids on both pre-ACDF and post-ACDF videofluoroscopies, thus controlling for individual variation and protocol variation.

RESULTS

After ACDF surgery, we found significant within-subject worsening of Penetration-Aspiration Scale (Rosenbek, Robbins, Roecker, Coyle, & Wood, 1996) scores, vallecular (but not piriform sinus) residue, superior (but not anterior) hyoid excursion, and posterior pharyngeal wall thickness. Results are discussed in the context of previous literature.

CONCLUSIONS

ACDF surgery can affect both physiological/anatomical and functional measures of swallowing. Future research should expand to other biomechanical and temporal variables, as well as greater bolus volumes and a wider array of viscosities and textures.

Do the complications increased in the anterolateral right-side approach to treat the cervical degenerative disorders? A retrospective cohort study

The dysphagia and recurrent laryngeal nerve (RLN) palsy are the most common complications of the patients who underwent anterior cervical surgery in the current literature. These morbidities have led to the study of the impact of sidedness in anterior cervical spine surgery. However, many reports documented the left-side was more effective and safe than right-side based on the anatomy. So the right-side approach is more challenging. We retrospectively study 503 patients with cervical degenerative diseases who underwent cervical spinal surgery using anterolateral right-side approach in our spine center from September 1999 to December 2012 and evaluate the efficient and safety of the anterolateral right-side approach to treat the cervical degenerative diseases. The overall mortality rate in our present report was 3.38% (17 of 503 patients). The most common complication which observed in 2.80% of our cases was dysphagia. Postoperatively, there was only one patient with hematoma and died (0.19%) and symptomatic recurrent laryngeal nerve palsy occurred in 0.39% of the cases. The anterolateral right-side anterior approach didn't increase the incidence of the dysphagia and recurrent laryngeal nerve (RLN) palsy.

Indications for Direct Laryngoscopic Examination of Vocal Cord Function Prior to Anterior Cervical Surgery

Recurrent laryngeal nerve palsy (RLNP) is among the most common complications in both thyroid surgeries and anterior approaches to the cervical spine, having both a diverse etiology and presentation. Most bilateral paresis, with subsequent devastating impact on patients, are due to failure to recognize unilateral recurrent laryngeal nerve paralysis and, although rare, are entirely preventable with appropriate history and screening. Recurrent laryngeal nerve palsy has been shown to present asymptomatically in as high as 32% of cases, which yields limitations on exclusively screening with physical examination. Based on the available literature, diagnosis of unilateral RLNP is the critical factor in preventing the occurrence of bilateral RLNP as the surgeon may elect to operate on the injured side to prevent bilateral paresis. Analysis of incidence rates shows postoperative development of unilateral RLNP is 13.1 (95% confidence interval [CI]: 6.1-28.1) and 13.90 (95% CI: 6.6-29.3) times more likely in anterior spine and thyroid surgery, respectively, in comparison with intubation. Currently, there is no consensus on when to order a preoperative laryngoscopic examination prior to anterior cervical spine surgery. The importance of patient history should be emphasized, as it is the basis for indications of preoperative laryngoscopy. Efforts to minimize postoperative complications must be made, especially when considering the rising rate of cervical fusion. This study presents a systematic review of the literature defining key causes of RLNP, with a probability-based protocol to indicate direct laryngoscopy prior to anterior cervical surgery as a screening tool in the prevention of bilateral RLNP.

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.

A retrospective evaluation of the etiology of unilateral vocal fold paralysis over the last 25 years

Previous studies have shown that the etiology of laryngeal paralysis has changed over the last decades, with an increase in the incidence of cases attributable to thyroid surgery. The aim of this study was to evaluate longitudinal changes in the etiology of unilateral vocal fold paralysis (UVFP) in a single institution over the last 25 years. This retrospective study analyzed the etiology of UVFP between 1990 and 2015 by comparing a cohort of patients treated in 1990-1992 with a cohort treated in 2013-2015. The final analysis was based on data concerning 356 patients (38.8 % males; mean age 55.3 ± 20.4 years): 113 in the 1990-1992 cohort, and 243 in the 2013-2015 cohort. The main cause of UVFP in the population as a whole was thyroidectomy (41.3 %), followed by an idiopathic origin (25.3 %) and thoracic surgery (12.1 %); this was confirmed in both intra-group analyses. There was a statistically significant association between etiology and the sub-group periods: the prevalence of post-thyroidectomy UVFP was highly significantly lower in the 2013-2015 cohort (35.4 vs 54.0 %), and the prevalence of idiopathic cases was higher (28.4 vs 18.6 %). Etiology significantly related to gender in both cohorts (p value ≤0.001). In the 2013-2015 cohort, there was also a statistically significant relationship between etiology and age classes (p value 0.017), and the left side was more frequently affected than the right (67.1 vs 32.9 %). Our findings document changes in the etiological pattern of UVFP over the last 25 years, with a considerable decrease in post-thyroidectomy UVFP, and a growing predominance of idiopathic and post-thoracic surgery UVFP.

Total Endoscopic Thyroidectomy with Intraoperative Laryngeal Nerve Monitoring

Objective. To evaluate the clinical efficacy of laryngeal nerve (LN) monitoring (LNM) during total endoscopic thyroidectomy via breast approach, with emphasis on the identification rates for RLN and EBSLN and the incidence of RLN paralysis. Materials and Methods. This retrospective study included 280 patients who underwent endoscopic thyroidectomy with or without LNM. RLN and EBSLN were identified using endoscopic magnification in the control group, while they were localized additionally by LNM in the LNM group. Demographic parameters and surgical outcomes were analyzed by statistical methods. Patients in the control group were also stratified by the side of thyroidectomy to determine difference in left and right RLN injury rates. Results. All procedures were successfully conducted without permanent LN damage. The identification rates for RLN and EBSLN were high in the LNM group compared to those of the control group, and the risk difference (RD) of temporary RLN injury between two groups was 6.3%. The risk of damage was slightly higher for the left RLN than for the right RLN in the control group, which was performed by a right-hand surgeon. Conclusion. The joint application of LNM and endoscopic magnified view endows total endoscopic thyroidectomy with ease, safety, and efficiency.

Differences in the microstructure and biomechanical properties of the recurrent laryngeal nerve as a function of age and location

Idiopathic onset of unilateral vocal fold paralysis (UVP) is caused by damage to the recurrent laryngeal nerve (RLN) and results in difficulty speaking, breathing, and swallowing. This damage may occur in this nerve as it loops around the aortic arch, which is in a dynamic biomechanical environment. The goal of this study is to determine if the location-dependent biomechanical and microstructural properties of the RLN are different in piglets versus adolescent pigs. The neck/distal and thoracic/proximal (near the aortic arch) regions of the RLN from eight adolescent pigs and six piglets were isolated and mechanically assessed in uni-axial tension. Two-photon imaging (second harmonic) data were collected at 5%, 10%, and 15% strain during the mechanical test. The tangential modulus (TM) and the strain energy density (W) were determined at each level of strain. The mean mode of the preferred fiber angle and the full width at half maximum (FWHM, a measure of fiber splay) were calculated from the imaging data. We found significantly larger values of TM, W, and FWHM in the proximal segments of the left RLN when compared to the distal segments (18.51 MPa ± 1.22 versus 10.78 MPa ± 1.22, p < 0.001 for TM, 0.046 MPa ± 0.01 versus 0.026 MPa ± 0.01, p < 0.003 for W, 15.52 deg ± 1.00 versus 12.98 deg ± 1.00, p < 0.001 for FWHM). TM and W were larger in the left segments than the right (15.32 MPa ± 1.20 versus 11.80 MPa ± 1.20, p < 0.002 for TM, 0.038 MPa ± 0.01 versus 0.028 MPa ± 0.01, p < 0.0001 for W). W was larger in piglets when compared to adolescent pigs (0.042 MPa ± 0.01 versus 0.025 MPa ± 0.01, p < 0.04). The proximal region of the left porcine RLN is more stiff than the distal region and has a higher degree of fiber splay. The left RLN of the adolescent pigs also displayed a higher degree of strain stiffening than the right. These differences may develop as a result of the more dynamic environment the left RLN is in as it loops around the aortic arch.

A computational study of the role of the aortic arch in idiopathic unilateral vocal-fold paralysis

Unilateral vocal-fold paralysis (UVP) occurs when one of the vocal folds becomes paralyzed due to damage to the recurrent laryngeal nerve (RLN). Individuals with UVP experience problems with speaking, swallowing, and breathing. Nearly two-thirds of all cases of UVP is associated with impaired function of the left RLN, which branches from the vagus nerve within the thoracic cavity and loops around the aorta before ascending to the larynx within the neck. We hypothesize that this path predisposes the left RLN to a supraphysiological, biomechanical environment, contributing to onset of UVP. Specifically, this research focuses on the identification of the contribution of the aorta to onset of left-sided UVP. Important to this goal is determining the relative influence of the material properties of the RLN and the aorta in controlling the biomechanical environment of the RLN. Finite element analysis was used to estimate the stress and strain imposed on the left RLN as a function of the material properties and loading conditions. The peak stress and strain in the RLN were quantified as a function of RLN and aortic material properties and aortic blood pressure using Spearman rank correlation coefficients. The material properties of the aortic arch showed the strongest correlation with peak stress [ρ = -0.63, 95% confidence interval (CI), -1.00 to -0.25] and strain (ρ = -0.62, 95% CI, -0.99 to -0.24) in the RLN. Our results suggest an important role for the aorta in controlling the biomechanical environment of the RLN and potentially in the onset of left-sided UVP that is idiopathic.

Vocal cord palsy after anterior cervical spine surgery: a qualitative systematic review

BACKGROUND CONTEXT

Vocal cord palsy (VCP) is a known complication of anterior cervical spine surgery. However, the true incidence and interventions to minimize this complication are not well studied.

PURPOSE

To conduct a systematic review to identify the incidence, risk, and interventions for VCP after anterior cervical spine surgery.

STUDY DESIGN

This is a qualitative systematic literature review.

SAMPLE

Prospective and retrospective trials of patients undergoing anterior cervical spine surgery that reported on postoperative VCP or recurrent laryngeal nerve palsy.

OUTCOME MEASURES

Primary: incidence of VCP after anterior cervical spine surgery; secondary: risk factors and interventions for prevention of VCP after anterior cervical spine surgery.

METHODS

Electronic searches were conducted on Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systemic Reviews for clinical studies reporting VCP in anterior cervical spine surgery, limited to studies published between 1995 and June 2013 in English and French languages. After selection of studies independently by two review authors, data on incidence, risk, and interventions were extracted. Qualitative analysis was performed on three domains: quality of studies, strength of evidence, and impact of interventions.

RESULTS

Our search has identified 187 abstracts, and 34 studies met our inclusion criteria. The incidence of VCP ranges from 2.3% to 24.2%. Significant heterogeneity in study design and definition of VCP were used in the published studies. There is good evidence that reoperation increases the risk of VCP. One study of moderate strength suggests that operating from the right side may increase the risk of VCP. Among the interventions studied, endotracheal tube (ETT) cuff pressure monitoring with deflation during retraction has shown to reduce the incidence from 6% to 2%, but this result was not confirmed by randomized control trials. Limited evidence exists for other interventions of intraoperative electromyographic monitoring and methylprednisolone.

CONCLUSIONS

Vocal cord palsy is a significant morbidity after anterior cervical surgery with incidence up to 24.2% in the immediate postoperative period, with a higher risk in reoperation of the anterior cervical spine. Moderate evidence exists for ETT cuff pressure adjustment in preventing this complication.

A Rapid and Accurate Technique for the Identification of the Recurrent Laryngeal Nerve

Objective:

We studied the anatomic relationship between the recurrent laryngeal nerve (RLN) and the third tracheal ring, which was very important for rapid identification of RLN in our hands.

Methods:

This study was initially performed using 8 fresh cadavers (4 female and 4 male). The transverse nerve location from the third trachea and the depth from its anterior surface were measured. We further observed the topography of RLN in relation to the trachea in 60 patients, between November 2008 and January 2011, at the Tri-Service General Hospital and Buddhist Tzu Chi General Hospital, Taipei Branch, Taiwan, with 46 lobo-isthmectomies and 14 total thyroidectomies. The time spent in identifying the RLN was also recorded.

Results:

Among cadaver groups, the transverse distance (width) and the vertical distance (depth) averaged 3.3 and 17.6 mm, respectively. Among the clinical cases, the width and depth averaged 4.4 and 14.6 mm, respectively. The depth measured in males was significantly deeper than that in females (22.3 vs 13.2 mm) ( P < .05). The time spent in identifying the RLN after starting dissection in the RLN triangle was not statistically significantly different between the cadaver group and the clinical group (10.6 ± 5.7 seconds and 15.5 ± 17.7 seconds, respectively; P > .05). The median time was 9 and 10 seconds, respectively. There was no statistically significant side-to-side difference in terms of the time spent in searching for the RLN.

Conclusion:

Using the third ring as guidance, our inferior-superior technique offers an extra benefit in identifying the RLN safely and quickly, as compared to the conventional inferior approach.

Occam paradox? A variation of tapia syndrome and an unreported complication of guidewire-assisted pedicle screw insertion

Study Design Case report. Clinical Question The clinical aim is to report on a previously unknown association between guidewire-assisted pedicle screw insertion and neuropraxia of the recurrent laryngeal nerve (RLN), and how this may overlap with the signs of Tapia syndrome; we also report our approach to the clinical management of this patient. Methods A 17-year-old male patient with idiopathic scoliosis experienced Tapia syndrome after posterior instrumentation and arthrodesis at the level of T1-L1. After extubation, the patient had a hoarse voice and difficulty in swallowing. Imaging showed a breach in the cortex of the anterior body of T1 corresponding to the RLN on the right. Results Otolaryngological examination noted right vocal fold immobility, decreased sensation of the endolarynx, and pooling of secretions on flexible laryngoscopy that indicated right-sided cranial nerve X injury and left-sided tongue deviation. Aspiration during a modified barium swallow prompted insertion of a percutaneous endoscopic gastrostomy tube before the patient was sent home. On postoperative day 20, a barium swallow demonstrated reduced aspiration, and the patient reported complete resolution of symptoms. The feeding tube was removed, and the patient resumed a normal diet 1 month later. Tapia syndrome, or persistent unilateral laryngeal and hypoglossal paralysis, is an uncommon neuropraxia, which has previously not been observed in association with a breached vertebral body at T1 along the course of the RLN. Conclusion Tapia syndrome should be a differential diagnostic consideration whenever these symptoms persist postoperatively and spine surgeons should be aware of this as a potential complication of guidewires in spinal instrumentation.

Preoperative laryngoscopic examination in patients undergoing repeat anterior cervical discectomy and fusion

STUDY BACKGROUND

Patients who experience a recurrent laryngeal nerve injury (RLI) after undergoing an Anterior Cervical Discectomy and Fusion (ACDF) procedure may eventually become asymptomatic. If patients with an asymptomatic vocal cord abnormality undergo a subsequent ACDF they may be at risk for developing bilateral vocal cord paralysis (VCP). Bilateral VCP is a potentially life threatening problem, requiring emergent tracheotomy in some cases. A program of referring patients for preoperative laryngoscopic examinations (PLE) who were being considered for a revision ACDF was instituted. This study reviews the results of these examinations and determines if the information gained impacted management.

METHODS

Patients who were referred for PLE prior to revision ACDF were identified from a prospectively maintained database during the period 2004 - 2010. All patients underwent examinations by an Otorhinolaryngologist specialist (ENT) using a nasopharyngoscope in combination with video stroboscopic examination.

RESULTS

23 patients were identified as having a PLE and subsequent revision ACDF. 18 patients underwent a single level ACDF and 5 patients underwent a previous 2 level surgery. Significant findings were found in 4 patients. 2 patients presented with asymptomatic VCP and 2 patients with chronic hoarseness. One was found with VCP and the other with a vocal cord mass. The revision procedures were performed on the same side as the previous ACDF.

CONCLUSIONS

17.3% of patients undergoing PLE exhibited abnormalities, affecting decision-making regarding side of approach for revision ACDF. PLE is a simple and effective way of screening patients for abnormalities prior to revision ACDF surgery.

Medial loop of v2 segment of vertebral artery causing compression of proximal cervical root

Objective

It is rare that the medial loop in the V2 segment of the vertebral artery (VA) causes compression of the proximal cervical root of the spinal cord without leading to bony erosion and an enlarged foramen. We evaluated the clinical significance and incidence of the medial loop in the V2 segment of the VA.

Methods

We reviewed the records from 1000 consecutive patients who had undergone magnetic resonance imaging evaluation of the cervical spine between January 2005 and January 2008. The inclusion criteria were that over a third of the axial aspect of the VA located in the intervertebral foramen was inside the line between the most ventral points of the bilateral lateral mass, and that the ipsilateral proximal root deviated dorsally because of the medial loop of the VA. We excluded cases of bone erosion, a widened foramen at the medial loop of the VA, any bony abnormalities, tumors displacing VA, or vertebral fractures. The medical records were reviewed retrospectively to search for factors of clinical significance.

Results

In six patients (0.6%), the VA formed a medial loop that caused compression of the proximal cervical root. One of these patients had the cervical radiculopathy that developed after minor trauma but the others did not present with cervical radiculopathy related to the medial loop of the VA.

Conclusion

The medial loop of the VA might have a direct effect on cervical radiculopathy. Therefore, this feature should be of critical consideration in preoperative planning and during surgery.

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.