Safety assessment of the use of ultrasonic energy in the proximity of the recurrent laryngeal nerve in a porcine model.

BACKGROUND: Advanced bipolar and ultrasonic energy have demonstrated reduction of operating time and blood loss in thyroidectomy. However, these devices generate heat and thermal dispersion that may damage adjacent structures such as the recurrent laryngeal nerve (RLN). This study was designed to evaluate the safety profile of the Harmonic Focus+® (HF+) device through the evaluation of thermal injury to the RLN using different algorithms of distance and time with state of the art technology. METHODS: 25 Vietnamese pigs underwent activation of HF+ in the proximity of their RLN. They were divided into 4 groups according to activation distance (3 mm, 2 mm, 1 mm and on the RLN). Time of activation, time between tones of the ultrasonic generator, changes in the electromyographic signal using continuous nerve neuromonitoring, vocal fold mobility assessed by direct laryngoscopy and histological thermal damaged were evaluated. RESULTS: None of the pigs had loss of signal in the electromyography during the procedure; only one pig had isolated transient decrease in amplitude and one increase in latency. One pig had transient vocal fold paresis in the group with activation on the nerve. Evaluation of the nerves by histology and immunohistochemistry did not show significant changes attributed to thermal injury. CONCLUSIONS: The use of ultrasonic energy close to the RLN is safe, provided that activation time does not exceed the necessary time to safely transect the tissue.

Comparison of 12-month anatomic and functional results between Z6 femtosecond laser-assisted and manual trephination in deep anterior lamellar keratoplasty for advanced keratoconus.

The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond-assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser-assisted DALK between November 2012 and November 2015 in Nantes university medical center. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond-assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27; 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27; 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up respectively, showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean pachymetry was similar in both groups, and average endothelial cell density was 2390 cells/mm2 for femto DALK versus 2531 cells/mm2 for manual DALK at 12 months of follow-up, showing no statistically significant difference (P=0.5726). The rate of Descemet's membrane microperforations during the procedure was low and similar for both groups. Our study allows for a 12-month follow-up, with assessment of visual recovery, anatomic result and endothelial safety in a series of 19 femtosecond laser-assisted DALK with no statistical significant difference versus the manual trephination group. Femtosecond laser allows for increased reproducibility of the DALK procedure without reducing adverse effects during surgery. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. A medical economics study would be necessary to determine the cost-effectiveness of femtosecond laser-assisted DALK.

Dural involvement in skull base tumors--accuracy of preoperative radiological evaluation and intraoperative assessment.

BACKGROUND: Dural involvement is an important consideration in assessment of cranial base tumors dictating resectability and prognosis. Preoperative as well as intraoperative clues are valuable but not always correct. We evaluated a consecutive series of craniofacial resections at our center to correlate radiologically suspected dural involvement vis-à-vis intraoperative assessment and eventual pathology. METHODS: We conducted a retrospective analysis of cases of skull base tumors where potential dural involvement was considered. We recorded the preoperative radiological impression (contrast-enhanced magnetic resonance imaging) regarding dural involvement (normal, extradural, intradural, parenchymal disease), intraoperative impression (normal, adherent, subdural, parenchymal disease), and final histology (normal, reactive, tumor). We also recorded instances where the dura was resected and/or inadvertently breached and the incidence of postoperative cerebrospinal fluid leak and meningitis. RESULTS: One hundred twenty-seven cases were evaluated. Transcranial approaches were performed in 68 cases. Nineteen percent (24 cases) were endoscopic procedures. Dural resection was performed in 38 cases (30 being proven pathologically). The incidence of cerebrospinal fluid leak was 4.7%. The sensitivity, specificity, positive predictive value, and negative predictive value of magnetic resonance assessment were 34.5%, 97.9%, 83.3%, and 83.2%, respectively, providing an overall accuracy of 84%, and those for intraoperative dural adherence were 84.6%, 85.6%, 44%, 97.6%, and 85.5.%, respectively. CONCLUSIONS: Preoperative magnetic resonance imaging, although a good modality for imaging the disease extent, may not always identify the extent of dural involvement. Intraoperative assessment therefore becomes very important especially when it is unequivocally normal. Both should be used to ensure accurate treatment strategies and tailor the need for dural resection.

Assessment of acute injuries and chronic intimal thickening of the radial artery after transradial coronary intervention by optical coherence tomography.

AIMS: Transradial coronary intervention (TRI) introduces a trauma to the radial artery (RA), possibly influencing quality as a bypass conduit if subsequently used. We sought to determine the acute and chronic effects of TRI on the RA by optical coherence tomography (OCT). METHODS AND RESULTS: Immediately after TRI completion, 73 RAs in 69 patients were examined. The sheath was pulled back 2 cm distal to the puncture site, and OCT imaging was performed. The acute injuries and intimal thickening were compared between first-TRI RAs and repeat-TRI RAs. Intimal tears were observed in 49 RAs (67.1%) and were more frequent in the distal than in the proximal RA (P = 0.001). Medial dissections were not uncommon (26 RAs, 35.6%). The frequency of acute injury was significantly higher in repeat-TRI RAs (P < 0.001). Intima/medial area, the maximum intimal thickness/medial thickness ratio, and per cent narrowing were all significantly greater in repeat-TRI RAs in the distal and proximal RA. Multivariate analysis revealed that a repeated TRI procedure was the only independent predictor of intimal thickening. CONCLUSION: Optical coherence tomography clearly demonstrated significant acute injuries and chronic intimal thickening of RA after TRI. Further study should evaluate the impact of these effects when TRI RAs are subsequently used as conduits, on long-term graft patency and on clinical outcomes after bypass surgery.

Major vascular injury during anterior lumbar spinal surgery: incidence, risk factors, and management.

STUDY DESIGN: Retrospective chart review. OBJECTIVE: To examine the incidence of major vascular injury during anterior lumbar spinal surgery, attempt to identify predisposing risk factors, and to discuss management techniques. SUMMARY OF BACKGROUND DATA: Major vascular injury can be a catastrophic complication of anterior lumbar spinal surgery. METHODS: Current procedural terminology codes were used to identify the occurrence of major vascular injury, defined as injury to the iliac vessels, vena cava, and aorta. Once identified, the office record, hospital chart, operative note, and diagnostic test results were reviewed in detail. RESULTS: Three hundred forty-five operations were performed on 338 patients. Incidence of major vascular complication was 2.9% (10 of 345). There were 9 injuries of the common iliac vein and a single aortic injury. Risk factors identified in patients with major vascular injury were current or previous osteomyelitis or discogenic infection (n = 3), previous anterior spinal surgery (n = 2), spondylolisthesis (n = 2; 1 isthmic Grade II, 1 iatrogenic Grade II), large anterior osteophyte (n = 2), transitional lumbosacral vertebra (n = 1), and anterior migration of interbody device (n = 1). Lateral venorrhaphy by suture (n = 6) and hemoclip application (n = 2) was augmented by topical agents, which constituted the sole method of repair on 1 occasion. Magnetic resonance venography demonstrated iliac vein thrombosis in 1 patient. CONCLUSION: Current or previous osteomyelitis or discogenic infection, previous anterior spinal surgery, spondylolisthesis, osteophyte formation, transitional lumbosacral vertebra and anterior migration of interbody device point to an increased risk of vascular injury during anterior lumbar spinal surgery. Careful handling of the vascular structures and liberal use of topical hemostatic agents can lead to control of hemorrhage and preservation of vascular patency. Routine postoperative surveillance for proximal deep vein thrombosis, by magnetic resonance venography of the pelvic veins and inferior vena cava, should be performed after venorrhaphy.

Intracranial neuronavigation with intraoperative magnetic resonance imaging.

PURPOSE OF REVIEW: This is an invited review regarding the use of intraoperative magnetic resonance imaging in the neurosurgical setting. The medical literature evaluating the intraoperative use of magnetic resonance imaging for neurosurgery has increased steadily since the implementation of this technique 10 years ago. The present review discusses recent findings and the current use of intraoperative magnetic resonance imaging in neurosurgery with special emphasis on the quality of available evidence. RECENT FINDINGS: Intraoperative use of magnetic resonance imaging is a safe technique that enables the neurosurgeon to update data sets for navigational systems, to evaluate the extent of tumor resection and modify surgery if necessary, to guide instruments to the site of the lesion, and to evaluate the presence of intraoperative complications at the end of surgery. Although recent findings support the safety and efficacy of intraoperative magnetic resonance imaging for the above-mentioned purposes, there is no convincing evidence regarding its prognostic significance in the neurosurgical setting. SUMMARY: Although the use of intraoperative magnetic resonance imaging in neurosurgery has increased significantly within the last 10 years, currently there are less than two dozen dedicated intraoperative units in the United States. The popularization of this technique depends on both economic justification and high-quality scientific evidence supporting its prognostic importance regarding patient outcome.

[Intraoperative assessment of the reconstruction of atrioventricular valves using transesophageal echocardiography]. / Intraoperative Beurteilung der Rekonstruktion von Atrioventrikularklappen mittels transösophagealer Echokardiographie.

To obtain good results in cardiac valve reconstruction surgery it is necessary to assess intraoperatively the efficiency of mitral or tricuspid valve repair. In 15 patients (three with mitral stenosis, 12 with mitral insufficiency) the mitral valve, in eight patients the tricuspid valve and in two patients both av-valves were reconstructed individually by commissurotomy and/or annulorrhaphy. During cardiac arrest, the valves were tested by filling the left or right ventricle with saline solution. After weaning from the extra-corporeal-circulation (ECC) I-2 cm3 of agitated Gelifundol were injected into the ventricle and the amount of regurgitation of micro-bubbles into the atrium was assessed by intraoperative two-dimensional transesophageal echocardiography. In 20 patients, testing during cardiac arrest and contrast echocardiography showed identical and good results. In two patients, the efficiency of mitral or tricuspid reconstruction could be finally verified by transoesophageal echocardiography. In another patient who was operated because of HOCM and a severe mitral insufficiency, the Bigelow procedure was combined with mitral valve reconstruction. Intraoperative open testing showed a good functional result, but a remaining severe mitral insufficiency was detected by transesophageal contrast echocardiography. An intraoperative decision for valve replacement was made. Our results show that transesophageal contrast echocardiography is a simple and accurate method of assessing the efficiency of valve reconstruction procedures. In some cases it gives more information than testing during cardiac arrest.

[Assessment of heart valve reconstructive measures using intraoperative transesophageal contrast echocardiography]. / Beurteilung klappenrekonstruktiver Massnahmen mittels intraoperativer transoesophagealer Kontrastechokardiographie.

In 30 patients (6 mitral stenoses, 13 mitral insufficiencies, 12 tricuspid insufficiencies) intraoperative transoesophageal contrast echocardiography (TEE) was performed to examine the valve function after AV valve reconstruction. In the beating heart 1 ml of contrast medium was injected into the ventricle to assess the success of valve reconstruction by the extent of regurgitation into the left or right atrium respectively. In all 12 patients successful tricuspid valve reconstruction was detected. In 16/19 cases with mitral valve repair successful reconstruction has been demonstrated. In another 3 patients severe mitral insufficiency after valve repair was detected by TEE, finally intraoperative decision for valve replacement was made.