Prevention and management of dysphonia during anterior cervical spine surgery

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.

Reducing Dysphagia Following Anterior Cervical Spine Surgery: Insights From a Meta-Analysis

A systematic search was conducted across PubMed, Embase, and Cochrane Library databases to identify relevant studies. The analysis focused on the influence of surgical duration, the number of cervical levels treated, and implant types. A total of 21 studies were included, and heterogeneity among studies was evaluated using the I² statistic.  The results indicated that longer surgeries, multi-level procedures, and certain implant designs were associated with an increased risk of dysphagia. In contrast, low-profile implants and stand-alone cage systems demonstrated a reduced risk compared to traditional plate-and-cage constructs. Anterior plates and specific cage designs were linked to higher dysphagia rates. The findings suggest that the risk of dysphagia after anterior cervical spine surgery (ACSS) is influenced by the length of surgery, the number of motion segments treated, and implant design. Optimizing these factors could help reduce postoperative complications and improve patient outcomes.

Dysphagia After Anterior Cervical Spine Surgery: Pathophysiology, Diagnosis, and Management

Anterior cervical spine surgery (ACSS) is a surgical intervention widely used for a myriad of indications including degenerative, oncologic, inflammatory, traumatic, and congenital spinal conditions. A primary concern for surgeons performing ACSS is the postoperative development of oropharyngeal dysphagia. Current literature reports a wide incidence of this complication ranging from 1 to 79%. Dysphagia after ACSS is multifactorial, with common risk factors being prolonged duration of operation, revision surgeries, multilevel surgeries, and use of recombinant human bone morphogenetic protein-2. Many technical strategies have been developed to reduce the risk of postoperative dysphagia, including the development of low-profile implants and retropharyngeal local steroid application. In this article, we review the most recent literature regarding the epidemiology and pathophysiology, diagnostic criteria, risk factors, and management of dysphagia after ACSS.

Postoperative Measurement of the Retropharyngeal Space Predicts the Risk of Dysphagia After Anterior Cervical Diskectomy and Fusion

BACKGROUND AND OBJECTIVES

Postoperative dysphagia is a common complication of anterior cervical diskectomy and fusion (ACDF), although its pathophysiology remains poorly understood. Patients with severe dysphagia may suffer from serious complications such as aspiration pneumonia, in addition to difficulty with oral intake or malnutrition; therefore, a prompt indicator for postoperative management would be helpful. We quantitatively evaluated the retropharyngeal space (RS) after ACDF and investigated its association with postoperative dysphagia.

METHODS

This multicenter retrospective study analyzed the clinical data of 82 consecutive patients who underwent ACDF. The anteroposterior distance (APD) of the RS was measured at the C2 level using a lateral radiographic view on postoperative day 1. Postoperative dysphagia was subjectively assessed using the Bazaz-Yoo Dysphagia Severity Scale. We statistically evaluated the association between the APD of the RS and postoperative dysphagia.

RESULTS

The mean APD of the RS in all 82 patients was 3.6 mm preoperatively and significantly increased to 8.2 mm postoperatively (P < .0001). Twenty-two patients (26.8%) had postoperative dysphagia. Multivariable analysis revealed that the postoperative APD was associated with postoperative dysphagia (odds ratio 1.27, 95% CI 1.10-1.50, P = .0007). The receiver operating characteristic curve (area under the curve 0.70, 95% CI 0.58-0.83) demonstrated that the postoperative APD of the RS cutoff value was 6.1 mm, with a sensitivity of 100% and a specificity of 35%. With this cutoff value, the positive and negative predictive values for postoperative dysphagia were 36% and 100%, respectively.

CONCLUSION

Our data demonstrate that a value of 6.1 mm for the APD of the RS is an effective indicator for dysphagia after ACDF, which contributes to optimizing the patient management in the acute postoperative period.

Intraoperative Measurement of Endotracheal Tube Cuff Pressure and Its Change During Surgery in Correlation With Recurrent Laryngeal Nerve Palsies, Hoarseness, and Dysphagia After Anterior Cervical Discectomy and Fusion: A Prospective Randomized Controlled Trial

STUDY DESIGN

Prospective randomized controlled trial.

OBJECTIVES

Adjustment of endotracheal tube cuff pressure (ETCP) in anterior cervical discectomy and fusion (ACDF) may influence the incidence of complications such as recurrent laryngeal nerve palsy (RLNP), hoarseness, and dysphagia.

METHODS

The prospective randomized controlled trial was designed to investigate the influence of ETCP on the incidence of postoperative complications. All eligible patients underwent vocal cord examination before and after ACDF and were randomized into a control group (CG) and intervention group (IG). Endotracheal tube cuff pressure was passively monitored in CG, and in IG, it was maintained at 20 mmHg. Outcomes were evaluated during hospitalization and during follow-up.

RESULTS

A total of 98 patients were randomized, each group consisted of 49 patients. Statistical analysis showed that gender and age did not influence the incidence of complications. In CG, duration of retractor placement and extent of approach significantly impacted the occurrence of complications. The incidence of postoperative RLNP was 8.2% in IG and 12.2% in CG, hoarseness and dysphonia were present in 18.4% in IG and in 37.5% in CG, and dysphagia in 20.8% in IG and in 22.5% in CG. Hoarseness was significantly present more in CG (P = .018). Only one patient from CG presented with RLNP after 1 year, the remaining nine patients spontaneously recovered.

CONCLUSIONS

Unregulated ETCP can lead to a significantly higher incidence of hoarseness; however, its improvement rate is 100%. The early postoperative complication rate was higher in CG, and after one year, 1 patient had RLNP and 1 patient had dysphagia.

Upper cervical anterior fusion to C2 with temporary infrahyoid muscle detachment: a clinical case series and description of surgical technique

BACKGROUND

Anterior cervical spine surgery to C2 (ACSS-C2) is a challenging procedure that often results in postoperative persistent dysphagia or dyspnea due to injury to the internal branch of the superior laryngeal nerve (iSLN) or the relatively narrow and soft oropharynx. This study aimed to describe the surgical outcomes of our modified approach with temporary infrahyoid muscle detachment during ACSS-C2.

METHODS

Patients who underwent ACSS-C2 at two institutions between June 2015 and January 2022 were prospectively enrolled. Intraoperatively, we performed temporary detachment of the infrahyoid muscle from the hyoid bone to improve laryngeal mobility and accessibility to C2. This procedure also allowed for the easy identification and preservation of the iSLN. We retrospectively investigated the surgery-related complications and outcomes of bony fusion.

RESULTS

Twelve patients were enrolled in this study; five and seven patients underwent single- and multi-level fusion surgery, respectively. Intraoperative preservation of the iSLN and proper visualization of C2 were achieved in all cases. Subsequent decompression and instrumentation were successfully performed. Two older patients (78 and 81 years) who underwent multi-level fusion experienced transient postoperative dysphagia. None of the patients required unplanned reintubation or revision surgery because of instrumentation failure. Solid bony fusion was achieved in all cases.

CONCLUSIONS

Our modified approach with temporary infrahyoid muscle detachment during ACSS-C2 reduces the incidence of postoperative persistent dysphagia and dyspnea. However, in older patients at high risk for postoperative dysphagia, multi-level fusion should be avoided, and alternative procedures should be considered.

Vertebral Body Sliding Osteotomy as a Surgical Strategy for the Treatment of Cervical Myelopathy: Complications and Pitfalls

OBJECTIVE

This retrospective cohort study has been aimed at evaluating the incidence of complications after vertebral body sliding osteotomy (VBSO) and analyzing some cases. Furthermore, the complications of VBSO were compared with those of anterior cervical corpectomy and fusion (ACCF).

METHODS

This study included 154 patients who underwent VBSO (n = 109) or ACCF (n = 45) for cervical myelopathy and were followed up for > 2 years. Surgical complications, clinical and radiological outcomes were analyzed.

RESULTS

The most common surgical complications after VBSO were dysphagia (n = 8, 7.3%) and significant subsidence (n = 6, 5.5%). There were 5 cases of C5 palsy (4.6%), followed by dysphonia (n = 4, 3.7%), implant failure (n = 3, 2.8%), pseudoarthrosis (n = 3, 2.8%), dural tears (n = 2, 1.8%), and reoperation (n = 2, 1.8%). C5 palsy and dysphagia did not require additional treatment and spontaneously resolved. The rates of reoperation (VBSO, 1.8%; ACCF, 11.1%; p = 0.02) and subsidence (VBSO, 5.5%; ACCF, 40%; p < 0.01) were significantly lower in VBSO than in ACCF. VBSO restored more C2-7 lordosis (VBSO, 13.9° ± 7.5°; ACCF, 10.1° ± 8.0°; p = 0.02) and segmental lordosis (VBSO, 15.7° ± 7.1°; ACCF, 6.6° ± 10.2°; p < 0.01) than ACCF. The clinical outcomes did not significantly differ between both groups.

CONCLUSION

VBSO has advantages over ACCF in terms of low rate of surgical complications related to reoperation and significant subsidence. However, dural tears may still occur despite the lessened need for ossified posterior longitudinal ligament lesion manipulation in VBSO; hence, caution is warranted.

International and Multicenter Prospective Controlled Study of Dysphagia After Anterior Cervical Spine Surgery

BACKGROUND

In the context of anterior approach to the cervical spine, dysphagia is a common complication and still without a clear distinction of risk factors.

OBJECTIVE

To analyze the risk factors of dysphagia after cervical spine surgery.

METHODS

Multicenter prospective study evaluated patients who underwent anterior cervical spine surgery for degenerative pathologies, studying surgical, anesthesia, base disease, and radiological variables (preoperatively, 24 hours, 1 and 3 weeks, and 6 months after surgery), with control group matched. Postoperative dysphagia was assessed by Swallowing Satisfaction Index and Swallowing Questionnaire; besides, based on multiple logistic regression model, a risk factor analysis correlation was applied.

RESULTS

In total, 233 cervical patients were evaluated; most common level approached was C5-C6 (71.8%). All showed same decreasing trade for dysphagia incidence-with more cases on cervical group ( P < .05); severe cases were rare. At postoperative day 1, identified risk factors were approach to C3-C4 (4.11, P < .01), loss of preoperative cervical lordosis (2.26, P < .01), intubation attempts ≥2 (3.10, P < .01), and left side approach (1.85, P = .02); at day 7, body mass index ≥30 (2.29, P = .02), C3-C4 (3.42, P < .01), and length of surgery ≥90 minutes (2.97, P = .005); and at day 21, C3-C4 were kept as a risk factor (3.62, P < .01).

CONCLUSION

A high incidence level of dysphagia was identified, having a clear decreasing trending (number of cases and severity) through postoperative time points; considering possible risk factors, strongest correlation was the approach at the C3-C4 level-statistically significant at the 24 hours, 7 days, and 21 days assessment.

A Tapered Cuff Tracheal Tube Decreases the Need for Cuff Pressure Adjustment After Surgical Retraction During Anterior Cervical Spine Surgery: A Randomized Controlled, Double-Blind Trial

Background

Surgical retraction to expose the vertebrae during anterior cervical spine surgery increases tracheal tube cuff pressure and may worsen postoperative sore throat and dysphonia. This randomized double-blind study investigated the effect of cuff shape on intraoperative cuff pressure and postoperative sore throat and dysphonia.

Methods

Eighty patients were randomized to tracheal intubation with a tapered cuff or a conventional cylindrical high-volume low-pressure cuff (control) during anesthesia. Intraoperative cuff pressures were compared. The primary outcome was the incidence of pressure adjustment needed when the cuff pressure increased to &gt; 25 mm Hg after surgical retraction. The secondary outcome was the incidence of postoperative sore throat and dysphonia.

Results

The incidence of pressure adjustment after surgical retraction was significantly lower in the tapered group than in the control group (13% vs. 48%; P = 0.001; relative risk reduction, 74%). The median [interquartile range (IQR)] cuff pressure (mm Hg) was significantly lower for the tapered cuff than for the control cuff before surgical retraction [9 (7–12) vs. 12 (10–15); P &lt; 0.001] and after retraction [18 (15–23) vs. 25 (18–31); P = 0.007]. The median (IQR) postoperative dysphonia score assessed by a single speech-language pathologist was lower in the tapered group than in the control group [4 (3–6) vs. 5.5 (5–7); P = 0.008].

Conclusion

A tapered cuff tracheal tube decreased the need for the adjustment of cuff pressure after surgical retraction during anterior cervical spine surgery, thereby avoiding intraoperative pressure increase. It also has a better outcome in terms of dysphonia.

Clinical Trial Registration

[www.clinicaltrials.gov], identifier [NCT04591769].

Applying High-Resolution Impedance Manometry for Detecting Swallowing Change in Anterior Cervical Spine Surgery Patients

Background

Objectively detecting perioperative swallowing changes is essential for differentiating the reporting of subjective trouble sensations in patients undergoing anterior cervical spine surgery (ACSS). Swallowing indicates the transmission of fluid boluses from the pharynx (velopharynx, oropharynx, and hypopharynx) through the upper esophageal sphincter (UES). Abnormal swallowing can reveal fluid accumulation at the pharynx, which increased the aspiration risk. However, objective evidence is limited. High-resolution impedance manometry (HRIM) was applied for an objective swallowing evaluation for a more detailed analysis. We aimed to elucidate whether HRIM can be used to detect perioperative swallowing changes in patients undergoing ACSS.

Methods

Fourteen patients undergoing elective ACSS underwent HRIM with the Dysphagia Short Questionnaire (DSQ, score: 0–18) preoperatively (PreOP), on postoperative at day 1 (POD1), and postoperative at day seven (POD7). We calculated hypopharyngeal and UES variables, including hypopharyngeal mean peak pressure (PeakP) and UES peak pressure, representing their contractility (normal range of PeakP, 69–280 mmHg; peak pressure, 149–548 mmHg). The velopharynx-to-tongue base contractile (VTI) was also calculated (normal range, 300–700 mmHg.s.cm), indicating contractility. The swallowing risk index (SRI) from HRIM combined with four hypopharyngeal parameters, including PeakP, represents the global swallowing function (normal range, 0–11). A higher SRI value indicated higher aspiration.

Results

SRI was significantly higher on POD1 (10.88 ± 5.69) than PreOP (6.06 ± 3.71) and POD7 (8.99 ± 4.64). In all patients, PeakP was significantly lower on POD1 (61.8 ± 18.0 mmHg) than PreOP (84.9 ±34.7 mmHg) and on POD7 (75.3 ± 23.4 mmHg). The UES peak pressure was significantly lower on POD1 (80.4 ± 30.0 mmHg) than PreOP (112.9 ± 49.3 mmHg) and on POD7 (105.6 ± 59.1 mmHg). Other variables, including VTI, did not change significantly among the three time points. DSQ scores were 1.36, 3.43, and 2.36 at PreOP, POD1, and POD7 respectively.

Conclusions

With similar trends in DSQ and SRI, swallowing was significantly decreased on POD1 because of decreased hypopharyngeal and UES contractility but recovered to the preoperative state on POD7 after ACSS. Applying HRIM is superior to DSQ in detecting mechanisms and monitoring the recovery from swallowing dysfunction.

Clinical Trial Registration

The study was registered at ClinicalTrials.gov (NCT03891940).

Laryngoscopic Screening Before Revision Anterior Cervical Spine Surgery: Is Vocal Cord Palsy a Relevant Factor in Deciding the Approach Direction?

STUDY DESIGN

Retrospective study.

OBJECTIVES

The aim was to evaluate the exact incidence of vocal cord palsy (VCP) caused by previous anterior cervical spine surgery (ACSS) and aid surgeons in deciding the approach direction in revision ACSS.

SUMMARY OF BACKGROUND DATA

The incidence of VCP detected by preoperative laryngoscopic screening before revision ACSS appeared to be much higher in previous reports than in our experience.

MATERIALS AND METHODS

We reviewed the data of 64 patients who underwent revision ACSS. Preoperative laryngoscopy was performed in all patients to detect VCP and/or structural abnormalities of the vocal cords. The patients' characteristics, laryngoscopy results, and symptoms before revision surgery that were potentially caused by previous recurrent laryngeal nerve injuries (voice change, foreign body sensation, and chronic aspiration) were recorded.

RESULTS

Laryngoscopy demonstrated no complete VCP or decreased vocal cord motility. Eleven patients (17.2%) showed vocal cord-related symptoms and 13 patients (20.3%) showed abnormal laryngoscopic findings without VCP. Four patients (6.2%) showed vocal cord-related symptoms and abnormal laryngoscopic findings simultaneously. At the initial operative level, no significant differences in vocal cord-related symptoms were observed between the upper and lower levels (C3-4-5 vs. C5-6-7). However, the frequency of vocal cord-related symptoms was significantly high at the larger number of levels (≥3 segments) (P=0.010).

CONCLUSIONS

In contrast to previous reports, this study demonstrated that VCP is rarely detected before revision ACSS. Therefore, deciding the approach direction with only vocal cord motility can be dangerous, and more attention is required in setting the approach direction in patients who show both vocal cord-related symptoms and abnormal laryngoscopic finding. In other cases, a contralateral approach which has a low risk of bilateral VCP could be utilized if necessary.

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

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

Recurrent Laryngeal Nerve Palsy after Anterior Cervical Discectomy and Fusion - Prevalence and Risk Factors

BACKGROUND AND STUDY AIMS

 Recurrent laryngeal nerve palsy (RLNP) is a potential complication of anterior discectomy and fusion (ACDF). There still is substantial disagreement on the actual prevalence of RLNP after ACDF as well as on risk factors for postoperative RLNP. The aim of this study was to describe the prevalence of postoperative RLNP in a cohort of consecutive cases of ACDF and to examine potential risk factors.

MATERIALS AND METHODS

 This retrospective study included patients who underwent ACDF between 2005 and 2019 at a single neurosurgical center. As part of clinical routine, RLNP was examined prior to and after surgery by independent otorhinolaryngologists using endoscopic laryngoscopy. As potential risk factors for postoperative RLNP, we examined patient's age, sex, body mass index, multilevel surgery, and the duration of surgery.

RESULTS

 214 consecutive cases were included. The prevalence of preoperative RLNP was 1.4% (3/214) and the prevalence of postoperative RLNP was 9% (19/211). The number of operated levels was 1 in 73.5% (155/211), 2 in 24.2% (51/211), and 3 or more in 2.4% (5/211) of cases. Of all cases, 4.7% (10/211) were repeat surgeries. There was no difference in the prevalence of RLNP between the primary surgery group (9.0%, 18/183) versus the repeat surgery group (10.0%, 1/10; p = 0.91). Also, there was no difference in any characteristics between subjects with postoperative RLNP compared with those without postoperative RLNP. We found no association between postoperative RLNP and patient's age, sex, body mass index, duration of surgery, or number of levels (odds ratios between 0.24 and 1.05; p values between 0.20 and 0.97).

CONCLUSIONS

 In our cohort, the prevalence of postoperative RLNP after ACDF was 9.0%. The fact that none of the examined variables was associated with the occurrence of RLNP supports the view that postoperative RLNP may depend more on direct mechanical manipulation during surgery than on specific patient or surgical characteristics.

The Presence of Thyroid Cartilage at the Surgical Level Reduces Early Dysphagia after Single-Level Anterior Cervical Surgery: A Retrospective Study

Background: Early dysphagia is a frequent complication of anterior cervical (AC) spine surgery. However, there are no reports that have discussed the correlation between early dysphagia and the positional relationship between thyroid cartilage and the surgical level.Methods: We retrospectively enrolled 82 patients in our hospital who underwent single-level AC discectomy performed by the same surgeon using the same internal fixation apparatus from 2015 to 2017. Swallowing difficulty was rated during the first five postoperative days using a 10-point scoring system. The positional relationship between the thyroid cartilage and the surgical level was defined as discectomy within the thyroid cartilage (IN group) or outside the thyroid cartilage (OUT group) using preoperative computed tomography (CT) images. The confounding factors such as gender, age, body mass index (BMI), hypertension, diabetes mellitus, drinking, smoking, operative level, operative time, and blood loss were analyzed by a binomial logistic regression.Results: The thyroid cartilage was most commonly located above the C5 level (65.1%). Early dysphagia developed in 47.6% of the patients during the first five postoperative days. The IN and OUT groups each contained 41 cases. The difference in the cumulative postoperative early dysphagia score between the IN and OUT groups was statistically significant (p < .05). The factors of gender, age, BMI, hypertension, diabetes mellitus, drinking, smoking, operative level, operative time, blood loss did not significantly influence the incidence of postoperative early dysphagia.Conclusions: We found that early dysphagia, which is a self-limiting complication, was correlated with surgery performed at levels outside the thyroid cartilage region. Preoperative review of the positional relationship between the thyroid cartilage and the surgical level can predict the incidence of postoperative transient dysphagia.

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.

Dysphagia Rates after Anterior Cervical Diskectomy and Fusion: A Systematic Review and Meta-Analysis

STUDY DESIGN

 Systematic review and meta-analysis.

OBJECTIVE

Anterior cervical diskectomy and fusion (ACDF) is an effective surgical option for patients with cervical radiculopathy, myelopathy, or deformity. Although ACDF is generally safe, dysphagia is a common complication. Despite its high incidence, prolonged postoperative dysphagia is poorly understood; its etiology remains relatively unknown, and its risk factors are widely debated.

METHODS

We searched MEDLINE, Scopus, Web of Science, and Embase for studies reporting complications for cervical diskectomy with plating. We recorded dysphagia events from all included studies and calculated effect summary values, 95% confidence intervals (CIs), Q values, and I² values.

RESULTS

Of the 7,780 retrieved articles, 14 met inclusion criteria. The overall dysphagia rate was 8.5% (95% CI 5.7 to 11.3%). The rate of moderate or severe dysphagia was 4.4% (0.4 to 8.4%). Follow-up times of <12, 12 to 24, and >24 months reported rates of 19.9% (6.0 to 33.7%), 7.0% (5.2 to 8.7%), and 7.6% (1.4 to 13.8%), respectively. Studies utilizing the Bazaz Dysphagia Score resulted in an increase in dysphagia diagnosis relative to studies with no outlined criteria (19.8%, 5.9 to 33.7% and 6.9%, 3.7 to 10.0%, respectively), indicating that the criteria used for dysphagia identification are critical. There was no difference in dysphagia rate with the use of autograft versus allograft.

CONCLUSIONS

This review represents a comprehensive estimation of the actual incidence of dysphagia across a heterogeneous group of surgeons, patients, and criteria. The classification scheme for dysphagia varied significantly within the literature. To ensure its diagnosis and identification, we recommend the use of a standardized, well-outlined method for dysphagia diagnosis.

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.

The Effect of Local Intraoperative Steroid Administration on the Rate of Postoperative Dysphagia Following ACDF: A Study of 245,754 Patients

STUDY DESIGN

A retrospective database analysis.

OBJECTIVE

The aim of this study is to compare rates of postoperative dysphagia, length of stay, infection, and wound complications following short and long anterior cervical discectomy and fusion (ACDF) in patients who received local intraoperative steroids and those who did not.

SUMMARY OF BACKGROUND DATA

Only one prior small institutional study has investigated the application of local steroids at the time of ACDF to decrease postoperative dysphagia.

METHODS

A large administrative database was utilized to compare rates of postoperative dysphagia, length of stay, and infectious complications within 90 days in patients who received local steroid following short (1-2 level) and long (3 or more level) ACDF and control groups who did not. Nonobtainable information within the database included type of steroid, application technique, outcome data, and incidence of miscoding and noncoding by physicians. Odds ratios (ORs), 95% confidence intervals (95% CIs) and P values were then calculated using SPSS.

RESULTS

The incidence of dysphagia was significantly lower (9.0% vs. 14.6%, P = 0.005) in patients who received local steroid in the long ACDF group (n = 322) than a control group who did not (n = 45,432). This was not observed (P = 0.198) in the short ACDF group who received steroid (n = 1770) compared with a control group who did not (n = 198,230). The mean difference in length of stay was 1 day less for patients who received local steroid in both the short and long ACDF groups (P < 0.0001). The combined rate of postoperative infection and wound complications was not significantly different between steroid and control groups (P = 0.717).

CONCLUSION

This analysis of a large administrative database suggests that local intraoperative steroid is associated with a significantly reduced rate of postoperative dysphagia after long ACDF and reduced average length of stay following both long and short ACDF without any increase in the rate of postoperative infection or wound complication.

LEVEL OF EVIDENCE

3.

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.

Oropharyngeal Dysphagia after anterior cervical spine surgery: a review

Study Design Review. Objective Postoperative oropharyngeal dysphagia is one of the most common complications following anterior cervical spine surgery (ACSS). We review and summarize recent literature in order to provide a general overview of clinical signs and symptoms, assessment, incidence and natural history, pathophysiology, risk factors, treatment, prevention, and topics for future research. Methods A search of English literature regarding dysphagia following anterior cervical spine surgery was conducted using PubMed and Google Scholar. The search was focused on articles published since the last review on this topic was published in 2005. Results Patients who develop dysphagia after ACSS show significant alterations in swallowing biomechanics. Patient history, physical examination, X-ray, direct or indirect laryngoscopy, and videoradiographic swallow evaluation are considered the primary modalities for evaluating oropharyngeal dysphagia. There is no universally accepted objective instrument for assessing dysphagia after ACSS, but the most widely used instrument is the Bazaz Dysphagia Score. Because dysphagia is a subjective sensation, patient-reported instruments appear to be more clinically relevant and more effective in identifying dysfunction. The causes of oropharyngeal dysphagia after ACSS are multifactorial, involving neuronal, muscular, and mucosal structures. The condition is usually transient, most often beginning in the immediate postoperative period but sometimes beginning more than 1 month after surgery. The incidence of dysphagia within one week after ACSS varies from 1 to 79% in the literature. This wide variance can be attributed to variations in surgical techniques, extent of surgery, and size of the implant used, as well as variations in definitions and measurements of dysphagia, time intervals of postoperative evaluations, and relatively small sample sizes used in published studies. The factors most commonly associated with an increased risk of oropharyngeal dysphagia after ACSS are: more levels operated, female gender, increased operative time, and older age (usually >60 years). Dysphagic patients can learn compensatory strategies for the safe and effective passage of bolus material. Certain intraoperative and postoperative techniques may decrease the incidence and/or severity of oropharyngeal dysphagia after ACSS. Conclusions Large, prospective, randomized studies are required to confirm the incidence, prevalence, etiology, mechanisms, long-term natural history, and risk factors for the development of dysphagia after ACSS, as well as to identify prevention measures. Also needed is a universal outcome measurement that is specific, reliable and valid, would include global, functional, psychosocial, and physical domains, and would facilitate comparisons among studies. Results of these studies can lead to improvements in surgical techniques and/or perioperative management, and may reduce the incidence of dysphagia after ACSS.

Long-term result of vocal cord paralysis after anterior cervical disectomy

PURPOSE

Anterior cervical disectomy and fusion (ACDF) is a highly effective and safe method for spinal cord and cervical root decompression. However, vocal cord paralysis (VCP) remains an important cause of postoperative morbidity. The true incidence and recovery course of postoperative VCP is still uncertain. This study is a report on VCP after ACDF to evaluate the incidence, recovery course, and possible risk factors.

METHODS

From 2004 to 2008, 1,895 consecutive patients underwent ACDF in our hospital and were followed up for at least 3 years. All surgeons were well trained and used a right-sided exposure. Prolonged VCP, where patients suffered from postoperative VCP lasting more than 3 months, was recorded and analyzed.

RESULTS

In this retrospective study, 9 of the 1,895 patients (0.47%) documented prolonged VCP lasting over 3 months. Six of the nine patients had total recovery within 9 months. Only three patients (0.16%) still had symptoms even after 3 years postoperatively. All symptoms of VCP, except hoarseness, could be improved. After matching with 36 non-VCP patients, no differences with regard to longer operative or anesthesia time, shorter neck, obesity, and prevertebral edema. All cases of prolonged course of postoperative VCP occurred in patients who underwent exposure at the C67 level.

CONCLUSION

In our study, only 0.47% documented prolonged postoperative VCP, while most patients recovered within 9 months. However, if symptoms last longer, there could be almost permanent VCP (0.16%). In our study, choking and dysphagia subsided mostly within 6 months, but hoarseness remained. The exposure of the C67 level obviously was a risk factor for postoperative VCP.