The impact of automatic retractors on the esophagus during anterior cervical surgery: an experimental in vivo study in a sheep model

Perioperative Complications of Anterior Decompression with Fusion in Degenerative Cervical Myelopathy-A Comparative Study between Ossification of Posterior Longitudinal Ligament and Cervical Spondylotic Myelopathy Using a Nationwide Inpatient Database

For ossification of the posterior longitudinal ligament (OPLL) and cervical spondylotic myelopathy (CSM), anterior decompression with fusion (ADF) can accurately achieve spinal decompression. However, the difference in perioperative complications in ADF between OPLL and CSM is poorly described. This study aimed to investigate the perioperative complication rates of patients with degenerative cervical myelopathy undergoing ADF, represented by OPLL and CSM, using a large national inpatient database. In the OPLL and CSM groups, postoperative complication (systemic and local) rates, reoperation rates, medical costs during hospitalization, and mortality after propensity score matching were compared. After matching, 1197 matched pairs were made. The incidence of total systemic complications was similar between both groups (OPLL, 12.4%; CSM, 12.2%). In the OPLL group, more perioperative local complications (cerebrospinal fluid leakage: CSFL, [OPLL, 2.7%; CSM, 0.3%] and surgical site infection: SSI [OPLL, 2.1%; CSM, 0.9%]) were detected, and the hospitalization cost was approximately $3200 higher than that in the CSM group. Moreover, medical costs were significantly higher in patients who experienced complications in both OPLL and CSM. The frequency of perioperative complications of OPLL and CSM in ADF was detailed using large real-world data. Compared to CSM, OPLL had more perioperative complications such as CSFL and SSI, and higher medical costs. Regardless of the disease, medical costs were significantly increased when perioperative complications occurred.

Comparison of Perioperative Complications in Anterior Decompression With Fusion and Posterior Decompression With Fusion for Cervical Spondylotic Myelopathy: Propensity Score Matching Analysis Using a Nationwide Inpatient Database

STUDY DESIGN

A retrospective cohort study with a national inpatient database.

OBJECTIVE

This study aimed to research the perioperative complication rates of cervical spondylotic myelopathy (CSM) patients who underwent anterior decompression with fusion (ADF) and posterior decompression with fusion (PDF) using a large national inpatient database and propensity score matching (PSM) analysis.

SUMMARY OF BACKGROUND DATA

There are several ways to successfully achieve surgical spinal decompression in CSM patients; however, evidence of the systemic complications and reoperation rates in ADF and PDF is lacking.

MATERIALS AND METHODS

We identified patients who were hospitalized for CSM and underwent either ADF or PDF from 2010 to 2016 using the Japanese Diagnosis Procedure Combination database. In the ADF and PDF groups, we compared postoperative complications (systemic and local), medical costs during hospitalization, and mortality before and after PSM. In addition, multivariate regression analysis was performed to identify risk factors for perioperative systemic complications.

RESULTS

A total of 1013 matched pairs were made after PSM. More perioperative systemic complications were detected in the ADF group than in the PDF group (at least 1 complication: ADF vs. PDF: 15.2% vs. 12.0%, P=0.038), especially for respiratory failure (1.4% vs. 0.4%, P=0.018), pneumonia (1.9% vs. 0.5%, P=0.004), and dysphagia (3.0% vs. 1.1%, P=0.003). The costs were ~$8000 higher (P<0.001) and the length of hospital stay was almost 5 days longer (P<0.001) in the PDF group. The risk factors for perioperative systemic complications in ADF were high age, low body mass index, and preoperative respiratory disease, and the factors in PDF were high body mass index and preoperative renal disease.

CONCLUSION

More systemic complications, especially respiratory events, were more frequently observed in the ADF group, while the medical costs were higher and the hospital stay was longer in the PDF group.

LEVEL OF EVIDENCE

Level III.

Anterior Reconstruction Techniques for Cervical Spine Deformity

Cervical spine deformity is an uncommon yet severely debilitating condition marked by its heterogeneity. Anterior reconstruction techniques represent a familiar approach with a range of invasiveness and correction potential-including global or focal realignment in the sagittal and coronal planes. Meticulous preoperative planning is required to improve or prevent neurologic deterioration and obtain satisfactory global spinal harmony. The ability to perform anterior only reconstruction requires mobility of the opposite column to achieve correction, unless a combined approach is planned. Anterior cervical discectomy and fusion has limited focal correction, but when applied over multiple levels there is a cumulative effect with a correction of approximately 6° per level. Partial or complete corpectomy has the ability to correct sagittal deformity as well as decompress the spinal canal when there is anterior compression behind the vertebral body. If pathoanatomy permits, a hybrid discectomy-corpectomy construct is favored over multilevel corpectomies. The anterior cervical osteotomy with bilateral complete uncinectomy may be necessary for angular correction of fixed cervical kyphosis, and is particularly useful in the midcervical spine. A detailed understanding of the patient's local anatomy, careful attention to positioning, and avoiding long periods of retraction time will help prevent complications and iatrogenic injury.

Comparison of Perioperative Complications Between Anterior Decompression With Fusion and Laminoplasty For Cervical Spondylotic Myelopathy: Propensity Score-matching Analysis Using Japanese Diagnosis Procedure Combination Database

STUDY DESIGN

A retrospective comparative study with a large national database.

OBJECTIVE

The objective of this study was to compare the perioperative complications and costs of anterior decompression with fusion (ADF) and laminoplasty (LAMP) for patients who had cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

CSM is the most common spinal cord disorder in the upper middle-aged people in Japan. ADF and LAMP represent 2 major treatments; however, few studies have reported large-scale investigations for perioperative complications with CSM. Thus, it is controversial which surgical approach will lead to the best clinical outcome in CSM.

MATERIALS AND METHODS

All data in this study were collected from the Japanese Diagnosis Procedure Combination database for patients diagnosed with CSM. We adjusted for known confounding biases with propensity score matching. One-to-one matched pairs between each surgical procedure were analyzed for the purposes of comparing systemic complication rates, local complication rates, medical costs, and mortality.

RESULTS

After propensity score matching, 1638 pairs of patients undergoing ADF and LAMP were made. More perioperative systemic complications were observed in the ADF group, such as atrial fibrillation (ADF/LAMP=0.7%/0.2%, P=0.032), respiratory failure (1.4%/0.1%, P<0.001), dysphagia (2.2%/0.2%, P<0.001), and sepsis (0.5%/0.1%, P=0.019). In contrast, a high rate of pulmonary embolism was observed with LAMP groups (ADF/LAMP=0%/0.2%, P=0.045). Local complications, such as infection (ADF/LAMP=0.8%/1.7%, P=0.026) and meningitis (0%/0.2%, P<0.045), were more common in the LAMP group. Conversely, spinal fluid leakage (ADF/LAMP=0.6%/0%, P=0.003) was more common in the ADF group. The costs (P<0.001) were higher in the ADF group.

CONCLUSIONS

More systemic complications, such as respiratory disease, cardiovascular events, and sepsis, were observed in the ADF group, although local infection was more frequently seen in the LAMP group. Medical costs were higher in the ADF group. The findings in this study will contribute to each CSM patient by allowing suitable adaptation of cervical surgeries.

LEVEL OF EVIDENCE

Level III.

Manual preoperative tracheal retraction exercise decreases the occurrence of postoperative oropharyngeal dysphagia after anterior cervical discectomy and fusion

OBJECTIVE

Preoperative tracheal retraction exercise (TRE) to minimize the occurrence of postoperative oropharyngeal dysphagia after anterior cervical spine surgery.

METHODS

A total of 220 patients admitted for elective anterior cervical spine surgery from January 2013 to December 2014 were retrospectively reviewed. The patients were allocated into two groups: TRE group and control group (without TRE). Modified dysphagia scoring system (MDSS) was used for evaluating the presence and severity of dysphagia symptoms at 1 week and 1, 3, and 6 months after surgery. Demographics such as age, gender, smoking, type of procedure, number of levels operated, duration of surgery, intraoperative blood loss, and instrumentation were analyzed. The clinical outcomes in both groups were compared with Neck Disability Index (NDI), Visual Analogue Scale (VAS) for arm and neck pain, and Odom's criteria for global outcome.

RESULTS

In the first week postoperatively, 86 patients (39.1%) developed dysphagia, which decreased to 72 (32.7%), 5 (2.3%), and 4 (1.8%) after 1, 3, and 6 months, respectively. The patients who received the TRE prior to surgery had significantly better MDSS scores ( p = 0.032 for second-level, 0.022 for third-level, and 0.009 for fourth-level fusions) than control group patients who did not receive TRE at the first week of surgery. At the 1-month follow-up, the followed-up patients for second- to fourth-level fusions in the TRE group had improved MDSS scores than those in the control group ( p = 0.041 for second-level, 0.025 for third-level, and 0.0011 for fourth-level fusions). MDSS scores showed no significant difference between both the groups at 1 and 3 months postoperatively for single level anterior cervical fusion. NDI and VAS scores didn't yield any significant difference. Global outcome by Odom's criteria was 88.6%.

CONCLUSION

Preoperative TRE can significantly reduce the occurrence of postoperative dysphagia after ACDF surgery. During follow-up, the incidence of postoperative dysphagia was significantly lower and had resolved at 3 months in all patients.

A Prospective Study of Interbody Fat Graft Application With the Anterior Contralateral Cervical Microdiscectomy to Preserve Segmental Mobility

BACKGROUND

Any surgical procedure aims at protecting mobile segments at the operated level, and the sagittal balance of the columna vertebralis. Interbody fusion has become an often applied technique in anterior cervical discectomy.

OBJECTIVE

To indicate that a minimally invasive technique in which we use interbody fat graft placement showed great results and effectiveness, especially in patients who were suffering from cervical paramedian disc herniation.

METHODS

In this study, 432 patients were observed from 2000 to 2013. All these consecutive patients had paramedian disc herniation. The initial 239 patients (group 1) underwent microdiscectomy without graft placement, whereas the remaining 193 patients (group 2) had a microdiscectomy with interbody fat graft insertion. The Neck Disability Index (NDI) and Short Form-36 (SF-36) were used to evaluate clinical outcomes. They were followed up for 5.3 years (range 2-13 years).

RESULTS

Spontaneous radiological fusion was noticed in 12% of group 1 patients and none of the group 2 patients. It has been observed that the mean overall cervical curvature (C2-7) angles and segmental lordosis did not change significantly in late follow-up findings. During both early and late follow-ups, all patients indicated a decreasing NDI score, but in late follow-up, an improving SF-36 score.

CONCLUSION

This surgical technique provides good direct decompression and preserves mobility at the treated level, while preventing disc collapse.

A microsurgical anterior cervical approach and the immediate impact of mechanical retractors: A case control study

Introduction:

A microsurgical anterior cervical approach with discectomy and fusion (MACDF) is one of the most widely used procedures for treating radicular disorders. This approach is highly successful; however, it is not free from complications. These can be associated with soft tissue injuries.

Aim of the Study:

The recognition of the risks for these complications should be identified for timely prevention and safe treatment.

Materials and Methods:

Study Design: Retrospective case control study. This study includes a retrospective case series of 37 patients, paying special attention to immediate complications related to the use of mechanical retraction of soft tissue (dysphagia, dysphonia, esophageal lesions and local hematoma); and a comparative analysis of the outcomes after changes in the retraction method.

Results:

All selected cases had a positive neurological symptom response in relation to neuropathic pain. Dysphagia and dysphonia were found during the first 72 h in 94.1% of the cases in which automatic mechanical retraction was used for more than one hour during the surgical procedure. A radical change was noted in the reduction of the symptoms after the use of only manual protective blades without automatic mechanical retraction: 5.1% dysphagia and 0% dysphonia in the immediate post-operative period, P = 0.001.

Conclusions:

Soft tissue damage due to the use of automatic retractors in MACDF is not minor and leads to general discomfort in the patient in spite of good neurological results. These problems most often occur when automatic retractors are used continuously for more than 1 hour, as well as when they are used in multiple levels. Dysphagia, dysphonia and local pain decreased with the use of transient manual blades for retraction, and with intermittent release following minimally invasive principles.

Does a medial retraction blade transmit direct pressure to pharyngeal/esophageal wall during anterior cervical surgery?

STUDY DESIGN

A prospective study of 25 patients who underwent anterior cervical surgery.

OBJECTIVE

To assess retraction pressure and the exposure of pharyngeal/esophageal (P/E) wall to the medial retractor blade to clarify whether medial retraction causes direct pressure transmission to the P/E wall.

SUMMARY OF BACKGROUND DATA

Retraction pressure on P/E walls has been used to explain the relation between the retraction pressure and dysphagia or the efficacies of new retractor blades. However, it is doubtful whether the measured pressure represent real retraction pressure on the P/E wall because exposure of the P/E in the surgical field could be reduced by the shielding effect of thyroid cartilage.

METHODS

Epi- and endoesophageal pressures were serially measured using online pressure transducers 15 minutes before retraction, immediately after retraction, and 30 minutes after retraction. To measure the extent of P/E wall exposure to pressure transducer, we used posterior border of thyroid cartilage as a landmark. Intraoperative radiograph was used to mark the position of the posterior border of thyroid cartilage. We checked out the marked location on retractors by measuring the distance from distal retractor tip.

RESULTS

The mean epiesophageal pressure significantly increased after retraction (0 mmHg: 88.7 ± 19.6 mmHg: 81.9 ± 15.3 mmHg). The mean endoesophageal pressure minimally changed after retraction (9.0 ± 6.6 mmHg: 15.7 ± 13.8 mmHg: 17.0 ± 14.3 mmHg). The mean location of the posterior border of thyroid cartilage was 7.3 ± 3.5 mm on the retractor blade from the tip, which means epiesophageal pressure was measured against the posterior border of thyroid cartilage, not against the P/E wall.

CONCLUSION

We suggest that a medial retraction blade does not transmit direct pressure on P/E wall due to minimal wall exposure and intervening thyroid cartilage. Our result should be considered when measuring retraction pressure during anterior cervical surgery or designing novel retractor systems.

Nasal continuous positive airway pressure inhibits gastroesophageal reflux in newborn lambs

Background

Using esophageal pHmetry, nasal CPAP (nCPAP) has been shown to decrease acid gastroesophageal reflux (GER) in adult humans. Although both GER (mainly non-acid) and nCPAP use are very frequent in newborns, the effect of nCPAP on GER in early life is unknown. Having recently shown that the newborn lamb is a unique model for studying neonatal GER, our main objective was to assess the effect of nCPAP on GER in newborn lambs.

Methods

Eight newborn lambs, aged 2–3 days, were studied. Continuous esophageal pH-Impedance monitoring and polysomnography were performed for six hours during both spontaneous breathing and nCPAP application at 6 cmH₂O (nCPAP6), in a randomized order. Results were compared in the two experimental conditions, as well as without CPAP during the following 6 hours.

Results

i) nCPAP₆ virtually abolished GER [mean ±SD reflux number for 6 h = 9.1±8.6 without nCPAP₆ vs. 0.6±1 with nCPAP₆, P<0.05]; ii) GER number was also reduced during the 6 h-period following nCPAP6 application (18±16 without nCPAP₆ vs. 7±8.1 with nCPAP₆, P<0.05); iii) nCPAP₆ decreased the depth and duration of lower esophageal sphincter relaxation.

Conclusions

nCPAP inhibits GER in the newborn lamb. Further clinical studies using different levels of nasal CPAP are needed to confirm this result in human infants.

Framework Surgery for Treatment of Unilateral Vocal Fold Paralysis

Laryngeal framework surgery is the current gold standard treatment for unilateral vocal fold paralysis. It provides a permanent solution to glottic insufficiency caused by injury to the recurrent laryngeal nerve. Various modifications to the original Isshiki type I laryngoplasty procedure have been described to improve voice and swallowing outcomes. The success of this procedure is highly dependent on the experience of the surgeon as it epitomizes the intersection of art and science in the field. The following article reviews the evidence, controversies, and complications related to laryngoplasty for unilateral vocal fold paralysis. It also provides a detailed analysis of how and when arytenoid-positioning procedures should be considered, and summarizes the literature on postoperative outcomes.

Effect of Preoperative Tracheal Stretch Exercise on Anterior Cervical Spine Surgery: A Retrospective Study

STUDY DESIGN

We designed a retrospective study on preoperative tracheal stretch exercise (TSE) before anterior cervical spine surgery. The changes in vital signs before and during the surgery and the postoperative clinical outcome were recorded and compared with none treated patients.

OBJECTIVE

The aim of this study was to evaluate whether the preoperative TSE is beneficial to the anterior cervical spine surgery and clinical outcome.

SUMMARY OF BACKGROUND DATA

Anterior approach to the cervical spine surgery requires prolonged retraction of the trachea and esophagus. Although the surgery can be managed to complete, related potential complications may occur.

METHODS

This is a retrospective study on 128 patients scheduled for anterior cervical spine surgery. Patients in the stretched group received preoperative TSE for 3 consecutive days before surgery, whereas the control group did not. During the preoperative exercise and the surgery, the changes in the vital signs were recorded and compared with the control group. The visual analogue scale, neck disability index (NDI), and the Clinical Symptom Score of the Japanese Orthopaedic Association (JOA) were also compared at different follow-up intervals, including 1, 3, and 6 months postoperation.

RESULTS

The changes in blood pressure, heart rate, and respiratory and swallowing rates during the first exercise are significantly greater than those during the last exercise (P<0.05). During the surgery, changes in the vital signs in the exercise patients are also significantly smaller than those in control patients (P<0.05), excluding the blood oxygen saturation. The significant differences were also observed with the postoperative NDI and JOA scores between the exercise and control group at 6 months (P<0.05).

CONCLUSIONS

Proper and systematic preoperative TSE has great significance for the success of anterior cervical spine surgery.

Absence of effect of nasal continuous positive airway pressure on the esophageal phase of nutritive swallowing in newborn lambs

OBJECTIVES

It is presently recommended that oral feeding be started in premature infants as soon as possible, often at an age at which nasal continuous positive airway pressure (nCPAP) is still required for ventilatory support. Our previous data showed that application of nCPAP up to 10 cmH2O in full-term lambs had no deleterious effect on cardiorespiratory safety, feeding efficiency, or on nutritive swallowing-breathing coordination. Besides fear of swallowing-breathing coordination disturbances, esophageal motility disruption by nCPAP could be a reason to delay oral feeding. To our knowledge, no study has focused on the effects of nCPAP on esophageal motility in the neonatal period. The aim of the present study was therefore to further assess the effects of nCPAP on oral feeding by assessing its effects on the esophageal phase of nutritive swallowing (nutritive esophagodeglutition).

METHODS

Six full-term lambs, ages 2 to 3 days, underwent esophageal multichannel intraluminal impedance-pH monitoring. Lambs were bottle-fed under 2 randomized conditions, namely spontaneous breathing and nCPAP 6 cmH(2)O.

RESULTS

Beyond confirmation of unaltered feeding efficiency, analysis of multiple variables measured by impedance monitoring revealed that nCPAP 6 does not alter nutritive esophagodeglutition in any way (nCPAP vs spontaneous breathing, P > 0.1 for all variables).

CONCLUSIONS

offering further support to neonatologists pleading for initiation of oral feeding in infants still on nCPAP, the present results set the foundations for similar clinical studies in preterm human infants to confirm the absence of effects of nCPAP on nutritive swallowing.

Milk temperature influences esophageal motility in the newborn lamb

Esophageal dysmotility is common in infants. We aimed to evaluate the influence of milk temperature on esophageal motility using multichannel intraluminal impedance-pH monitoring (MII-pH). Five healthy lambs, ages 2 to 3 days, underwent a MII-pH whereas bottle-fed randomly with 50 mL of ewe milk at 26 °C, 38.5 °C, and 41.5 °C. Impedance motility parameters were studied on 5 swallows at each temperature. At 38.5 °C we noted a higher total propagation velocity and a shorter total bolus transit time (TBTT) (P < 0.05). These unique results suggest a potential role of milk temperature alterations in improving oral feeding in infants with esophageal dysmotility.

Newborn lamb as a new model for studying gastroesophageal reflux

We aimed to determine whether the newborn lamb at term is a valid model for studying gastroesophageal reflux. Seven bottle-fed lambs, ages 2 to 3 days, underwent esophageal multichannel intraluminal impedance-pH monitoring (MII-pH). A total of 196 reflux episodes were recorded, including 73% alkaline and 27% weakly acidic. No acid refluxes were observed. Median bolus clearance time was 4  seconds (3; 5.5), and proximal reflux extent was 35% (26). This first report of MII-pH in the newborn mammal sets the foundations for future studies with physiological and clinical relevance to human neonates.