Comparison of retraction pressure between novel and conventional retractor systems—a cadaver study

Correlation of Voice Hoarseness and Vocal Cord Palsy: A Prospective Assessment of Recurrent Laryngeal Nerve Injury Following Anterior Cervical Discectomy and Fusion

BACKGROUND

Injury to the recurrent laryngeal nerve (RLN) has been implicated as a common complication following anterior cervical discectomy and fusion (ACDF) surgery. The purpose of this study is to determine the true incidence of voice hoarseness and RLN palsy following ACDF surgery, to determine the reliability of symptoms in the diagnosis of RLN injury, and to evaluate factors related to the development of these symptoms.

METHODS

All patients undergoing elective (primary or secondary) ACDF surgery at a single institution consented to and enrolled in the present study. All approaches were through the left side. Enrolled patients received both preoperative and postoperative (within 1 month following surgery) laryngoscopy by a fellowship-trained ENT physician for evaluation of RLN function. Patients also responded as to whether they were experiencing postoperative symptoms of dysphagia, aspiration, and voice changes.

RESULTS

In total, 108 patients were included in this study. Mean age of the population was 59.2 ± 10.7 years and mean body mass index was 31.2 ± 7.1 kg/m². Three patients had previously undergone a thyroidectomy, whereas 20 patients had undergone a previous ACDF. Average intubation time for ACDF surgery was 121.6 ± 38.5 minutes. After surgery and excluding patients who were experiencing preoperative symptoms, 19 patients (20.4%) complained of dysphagia, 2 patients (1.9%) complained of aspiration symptoms, and 5 patients (4.6%) complained of voice hoarseness. There was no incidence of vocal cord palsy from postoperative laryngoscopy. From multivariate analysis, endotracheal cuff pressure after retractor placement was correlated to postoperative voice hoarseness, dysphagia, and aspiration symptoms.

CONCLUSIONS

From the results of this prospective study, the RLN remained functional even a month after surgery despite several cases of postoperative dysphagia, aspiration, and voice changes. Endotracheal cuff pressure, number of vertebral levels, body mass index, and intubation time were important variables related to postoperative symptoms.

CLINICAL RELEVANCE

Voice hoarseness does not necessarily indicate recurrent laryngeal nerve injury after ACDF but may be caused by compressive forces on laryngeal tissue during retraction or intubation. Laryngoscopy should be performed in cases with high clinical suspicion.

LEVEL OF EVIDENCE

2.

The distance of the gluteal nerve in relation to anatomical landmarks: an anatomic study

INTRODUCTION

Gluteal insufficiency is of concern with lateral approaches to total hip arthroplasty. Damage to the branches of the superior gluteal nerve may cause degeneration of the innervated muscles. The direct anterior approach exploits the intermuscular and internerval interval between tensor fasciae latae laterally and sartorius and rectus femoris muscle medially. In this study, the distance of the superior gluteal nerve in relation to anatomical landmarks was determined.

MATERIALS AND METHODS

Two experienced surgeons implanted trial components in 15 alcohol glycerol fixed cadavers with 30 hips. The trials were removed, and the main branch of the superior gluteal nerve and muscular branches of the nerve were exposed from lateral.

RESULTS

No visual damage to the main nerve branches and the location of the nerve in relation to the greater trochanter were noted by an experienced surgeon. The superior gluteal nerve and its muscular branches crossed the muscular interval between the gluteus medius and tensor fasciae latae muscles at a mean distance of 39 mm from the tip of the greater trochanter.

CONCLUSIONS

The direct anterior approach for total hip arthroplasty minimizes the risk of injuring the superior gluteal nerve, which may result in a gluteal insufficiency. Special care should be paid on avoiding overstretching the tensor fasciae latea muscle using minimum force on retractors during surgery and by taking care of the entrance point of the superior gluteal nerve to the tensor fasciae latae.

Open Reduction Assisted With an External Fixator and Internal Fixation With Calcaneal Locking Plate for Intra-articular Calcaneal Fractures

BACKGROUND

The extensile lateral approach (ELA) has been considered to be a standard approach for displaced intra-articular calcaneal fractures (DICF) because it provides excellent exposure and allows direct reduction of the depressed posterior facet fragment. But continuous retraction during surgery needs sufficient manpower and may cause ischemia. Failure of rigid fixation of DICF will not allow for early weight bearing and may lead to a loss of reduction. To avoid these disadvantages, this study presents open reduction assisted with an external fixator and internal fixation with a calcaneal locking plate.

METHODS

A series of 58 patients with 62 DICFs were treated over a period of 49 months. All patients were clinically and radiologically followed up with a mean follow-up of 35 (range 29-42) months. Clinical follow-up included visual analog scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, and ability to work. Radiologic follow-up included axial and lateral radiographs and measurements of the Bohler angle and Gissane angle.

RESULTS

At the final follow-up, all fractures had healed. The mean VAS score was 2.9 (range 0 to 8, SD 1.9) and the average AOFAS score was 71 (range 55-85, SD 8.1). The mean postoperative Bohler angle immediately after the surgery was 28.3 degrees (range 13.0-44.6, SD 7.0), which decreased to 27.5 degrees (range 12.2-43.3, SD 7.0) at the final follow-up, and the mean postoperative Gissane angle after the surgery was 116.3 degrees (range 94.9-131.5, SD 9.0) which finally increased to 118.4 degrees (range 94.5-135.8, SD 9.3). No statistically significant differences regarding Bohler and Gissane angles were found between different Sanders fracture types ( P>.05).

CONCLUSION

The presented operative technique was found to provide comparable reduction of Sanders type II-IV injuries.

LEVEL OF EVIDENCE

Level III, case control study.

Retracting Soft Tissue in Minimally Invasive Hip Arthroplasty Using a Robotic Arm: A Comparison Between a Semiactive Retractor Holder and Human Assistants in a Cadaver Study

BACKGROUND

All surgical procedures in orthopedics involve the retraction of soft tissue. In this study, the performance of 3 assistants holding the medial retractor during minimally invasive hip arthroplasty was compared with a semiactive retractor holder in a cadaver setup.

METHODS

A total of 40 measurements on 3 cadavers were carried out with each subject (3 human, 1 robot) measuring each cadaver 10 times. The retractor was equipped with a sensor array on both sides, to measure variations of the retracting pressures over a 2-minute interval.

RESULTS

The semiactive retractor holder showed an almost constant performance compared with the test subjects. There was no significant reduction of the applied pressure and almost no variation during the 2-minute interval and across all measurements.

CONCLUSIONS

The performance of the semiactive retractor holder was more stable than that of a human assistant, making it suitable for intraoperative usage.

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.

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.

Dysphagia after anterior cervical discectomy and fusion: a prospective study comparing two anterior surgical approaches

BACKGROUND

The Smith-Robinson approach is commonly used to expose the vertebrae in anterior cervical discectomy and fusion (ACDF). Postoperative dysphagia has been frequently reported following this procedure. In this approach, surgical dissection can be carried out either lateral (LEO) or medial (MEO) to the omohyoid muscle. The purpose of this study was to compare the degree of dysphagia between the LEO and MEO groups.

METHODS

In this randomized, prospective study, 80 patients were enrolled and evenly divided into the MEO and LEO groups. Patients underwent two-level ACDF using a right-sided Smith-Robinson approach. Follow-up was obtained 1, 3, 6, 12 week and 6 months after surgery. The degree of dysphagia was assessed using a 14-item questionnaire from the SWAL-QOL survey.

RESULTS

There were no differences between the MEO and LEO groups with respect to age, gender, body mass index, or length of surgery. Overall, the SWAL-QOL scores were not different between the two groups at any of the follow-up time points. However, when the level of surgery was taken into consideration, the early postoperative SWAL-QOL scores were significantly lower in the C3-C4 subgroup when the MEO approach was used. Conversely, the SWAL-QOL scores were significantly lower in the C6-C7 subgroup when the LEO approach was used. Two patients with C6-C7 surgery in the MEO group also developed dysphonia that resolved spontaneously within 3 months.

CONCLUSION

The findings from this study suggest that the LEO approach should be selected if the level of surgery involves C3-C4. For C6-C7 surgery, however, a left-sided MEO approach should be used. Depending on surgeon's preference, either approach can be used if both cervical levels are involved.

Results of a prospective randomized study comparing a novel retractor with a Caspar retractor in anterior cervical surgery

BACKGROUND

Retraction injury might explain the soft tissue complications seen after anterior cervical surgery. A novel retractor system (Seex retractor system [SRS]) that uses a principle of bone fixation with rotation has been shown to reduce retraction pressure in a cadaveric model of anterior cervical decompression and fusion.

OBJECTIVE

To compare the conventional Cloward-style retractor (CRS) with the SRS in a prospective randomized clinical trial.

METHODS

After ethics and study registration (ACTRN 12608000430336), eligible patients were randomized to either the CRS or SRS before 1- or 2-level anterior cervical decompression and fusion. The pressure beneath the medial retractor blade was recorded with a thin pressure transducer strip. Postoperative sore throat, dysphagia, and dysphonia were assessed after 1, 7, and 28 days.

RESULTS

Twenty-six patients were randomized. There were no serious complications. Complication rates were low with a trend favoring SRS that was not statistically different. Average retraction pressure with SRS was 1.9 mm Hg and with CRS was 5.6 mm Hg (P < .001 on F test; P = .002 on 2-tailed t test). Mean average peak retraction pressure with the SRS was 3.4 mm Hg and with the CRS was 20 mm Hg (P < .001 on F test; P = .005 on 2-tailed t test).

CONCLUSION

The new retractor is safe, and statistically similar complication rates were observed with the 2 systems. The SRS generated significantly less retraction pressure compared with the CRS. This difference can be explained by the different principles governing the function of these retractors. Bone fixation gives stability and rotation reduces tissue pressure, both desirable in a retractor.