Mandibular subluxation as an adjunct to exposure of the distal internal carotid artery in endarterectomy surgery. Technical note

Cadaver investigation of the usefulness of the transstyloid diaphragm approach for high-position plaque carotid endarterectomy

OBJECTIVES

Patients sometimes present with high cervical internal carotid artery (ICA) stenosis. This study demonstrates the usefulness of the transstyloid approach to expose the distal ICA by dissection of the styloid diaphragm covering the distal cervical ICA for carotid endarterectomy (CEA). In particular, the possible exposure length achieved by this approach was investigated using cadaveric heads.

METHODS

The procedure of the transstyloid diaphragm approach was confirmed in 10 cadaveric heads (20 sides). After the carotid triangle was opened, both the posterior belly of the digastric muscle (PBDM) and the stylohyoid muscle could be divided. Then, the carotid sheath was dissected, and the glossopharyngeal nerve was identified crossing over the distal ICA. The revealed length of the ICA was measured with or without dissection of both the PBDM and the stylohyoid muscle. The specimens were dissected under the surgical microscope.

RESULTS

The transstyloid diaphragm approach was achieved successfully in all specimens. The revealed lengths of the ICA with and without dissection of the styloid diaphragm were 53.7 ± 5.9 mm and 38.8 ± 2.9 mm (mean ± standard deviation), respectively. Therefore, the revealed length of the distal ICA was 14.9 ± 4.5 mm greater using the transstyloid diaphragm approach compared to the regular CEA approach.

CONCLUSIONS

More of the ICA can be revealed by dissection of both the PBDM and the stylohyoid muscle. The transstyloid diaphragm approach might be helpful to reveal the distal ICA in cases of high cervical ICA stenosis.

Posterior cervical triangle approach for carotid endarterectomy: Technical note and results

INTRODUCTION

Carotid endarterectomy (CEA) is usually performed using the anterior cervical triangle as a surgical corridor but, when needed, the retromandibular space makes dissection of higher structures difficult in some cases. The posterior cervical triangle (PCT) can be useful in these demanding cases.

METHODS

We retrospectively reviewed cases from July 2013 to November 2019 in which PCT was used as an approach for CEA. The surgical technique used was explained, and the complications and evolution of the patients were analysed.

RESULTS

We found 7 CEAs performed through this approach, of which 2 presented transient trapezius paresis. There were no cases of severe complications in this series.

CONCLUSION

The PCT approach for performing CEA represents a useful and easy technique that avoids the need for mandibular mobilisation or osteotomies for lesions located in anatomically high carotid bifurcations.

Surgical access to the distal cervical segment of the internal carotid artery and to a high carotid bifurcation – integrative literature review and protocol proposal

Abstract Several different maneuvers have been described for obtaining access to the distal cervical segment of the internal carotid artery or to a high carotid bifurcation. However there are different approaches to systematization of these techniques. The objective of this study is to review the techniques described and propose a practical protocol to support selection of the most appropriate technique for each case. The review is based on the results of database searches on PubMed Central, the Virtual Health Library (BVSalud), and SciELO for articles on the subject published in English or Portuguese from 1980 to 2021. Among the different maneuvers described, it appears reasonable that the first two steps should be to obtain access at the sternocleidomastoid muscle, followed by section or retraction of the digastric muscle posterior belly. If needed, temporary unilateral mandibular subluxation is an additional resource that is preferable to division of the styloid apparatus process, because of its lesser potential for morbidity. Even wider exposure can be obtained using mandibular osteotomies.

Acesso cirúrgico ao segmento cervical distal da artéria carótida interna e à bifurcação carotídea alta – revisão integrativa da literatura e proposta de protocolo

Several different maneuvers have been described for obtaining access to the distal cervical segment of the internal carotid artery or to a high carotid bifurcation. However there are different approaches to systematization of these techniques. The objective of this study is to review the techniques described and propose a practical protocol to support selection of the most appropriate technique for each case. The review is based on the results of database searches on PubMed Central, the Virtual Health Library (BVSalud), and SciELO for articles on the subject published in English or Portuguese from 1980 to 2021. Among the different maneuvers described, it appears reasonable that the first two steps should be to obtain access at the sternocleidomastoid muscle, followed by section or retraction of the digastric muscle posterior belly. If needed, temporary unilateral mandibular subluxation is an additional resource that is preferable to division of the styloid apparatus process, because of its lesser potential for morbidity. Even wider exposure can be obtained using mandibular osteotomies.

Doppler is a Safe Criterion for Ensuring the Implementation of Eversion Carotid Endarterectomy

Objective: This is a prospective study concerning patients with symptomatic or asymptomatic significant carotid stenosis. Preoperative and intraoperative measurements of the peripheral extension of the carotid atherosclerotic plaque have been compared with postoperative measurements to identify a preoperative method that safely allows the performance of eversion carotid endarterectomy (ECEA).

Materials and Methods: The study included 37 patients with symptomatic internal carotid stenosis greater than 70% and 43 patients with asymptomatic stenosis greater than 80%. Four methods were used for establishing criteria: preoperative Doppler examination, intraoperative measurement of the carotid atheroma before artery division, measurement of the removed plaque, and histological measurement of the plaque.

Results: Preoperative Doppler examination is a method of estimating the actual distal extension of the internal carotid artery (ICA) atheroma, with correction as dictated by the following formula:AL= 0.6704+0.7685⋅Doppler

In all cases, preoperative ultrasound measurements and intraoperative estimation confirmed the correct decision to proceed with the eversion technique.

Conclusion: The peripheral extension of the atherosclerotic plaque of the ICA can be assessed with accuracy by preoperative Doppler study, which can be used with safety as a predicting criterion of the existence of healthy peripheral carotid tissue that allows the performance of the eversion endarterectomy technique.

Exoscopic carotid endarterectomy using movable 4K 3D monitor: Technical note

Background:

Carotid endarterectomy (CEA) using conventional surgical microscope has been already established as golden standard. Recently, exoscope was introduced into the field of neurosurgery, and various merits of it have been reported. We report the experiences of exoscopic CEA using a movable 4K 3D monitor and discuss the feasibility of it.

Methods:

We report a consecutive series of 15 cases of exoscopic CEA for internal carotid artery (ICA) stenosis using a movable 4K 3D monitor between January 2020 and April 2021. We utilized ORBEYE as an exoscope system and a 31-inch movable 4K 3D monitor, which was installed in the Maquet Moduevo ceiling supply unit.

Results:

In all 15 cases, the procedures were accomplished only using the ORBEYE. There were no operative complications due to the use of the exoscope. In response to the operative site, the 4K 3D monitor was moved to face the operator. Even when the angle of the visual axis of the exoscope against the horizontal plane was small during the surgical manipulation in the distal portion of ICA, the operator was able to maintain a comfortable posture.

Conclusion:

Using the movable 4K 3D monitor, exoscopic CEA can be performed ergonomically. The operator can manipulate the distal portion of the ICA or proximal portion of the common carotid artery in a comfortable posture and face the monitor by adjusting its position.

Surgical Technique for Carotid Endarterectomy: Current Methods and Problems

Over the last 60 years, many reports have investigated carotid endarterectomy (CEA) and techniques have thus changed and improved. In this paper, we review the recent literature regarding operational maneuvers for CEA and discuss future problems for CEA. Longitudinal skin incision is common, but the transverse incision has been reported to offer minimal invasiveness and better cosmetic effects for CEA. Most surgeons currently use microscopy for dissection of the artery and plaque. Although no monitoring technique during CEA has been proven superior, multiple monitors offer better sensitivity for predicting postoperative neurological deficit. To date, data are lacking regarding whether routine shunt or selective shunt is better. Individual surgeons thus need to select the method with which they are more comfortable. Many surgical techniques have been reported to obtain distal control of the internal carotid artery in patients with high cervical carotid bifurcation or high plaque, and minimally invasive techniques should be considered. Multiple studies have shown that patch angioplasty reduces the risks of stroke and restenosis compared with primary closure, but few surgeons in Japan have been performing patch angioplasty. Most surgeons thus experience only a small volume of CEAs in Japan, so training programs and development of in vivo training models are important.

A Randomized Controlled Trial Examining the Effect of the Addition of the Mandibular Block to Cervical Plexus Block for Carotid Endarterectomy

OBJECTIVES

Although the cervical plexus block generally provides adequate analgesia for carotid endarterectomy, pain caused by metal retractors on the inferior surface of the mandible is not prevented by the cervical block. Different pain relief methods can be performed for patients who experience discomfort in these areas. In this study, the authors evaluated the effect of mandibular block in addition to cervical plexus block on pain scores in carotid endarterectomy.

DESIGN

A prospective, randomized, controlled trial.

SETTING

Training and research hospital.

PARTICIPANTS

Patients who underwent a carotid endarterectomy.

INTERVENTIONS

Patients scheduled for carotid endarterectomy under cervical plexus block were randomized into 2 groups: group 1 (those who did not receive a mandibular block) and group 2 (those who received a mandibular block). The main purpose of the study was to evaluate the mandibular block in addition to cervical plexus block in terms of intraoperative pain scores.

MEASUREMENTS AND MAIN RESULTS

Intraoperative visual analog scale scores were significantly higher in group 1 (p = 0.001). The amounts of supplemental 1% lidocaine and intraoperative intravenous analgesic used were significantly higher in group 1 (p = 0.001 and p = 0.035, respectively). Patient satisfaction scores were significantly lower in group 1 (p = 0.044). The amount of postoperative analgesic used, time to first analgesic requirement, postoperative visual analog scale scores, and surgeon satisfaction scores were similar in both groups. There was no significant difference between the groups with respect to complications. No major neurologic deficits or perioperative mortality were observed.

CONCLUSIONS

Mandibular block in addition to cervical plexus block provides better intraoperative pain control and greater patient satisfaction than cervical plexus block alone.

Technical options for the treatment of extracranial carotid aneurysms

Extracranial carotid artery aneurysm (ECAA) is an uncommon but serious condition. The morbidity and mortality of ECAA are assumed to be high when untreated. ECAA treatment presents a challenge because of accessibility of the carotid artery and lack of evidence-based guidelines. When exclusion of the aneurysm is considered, surgical resection of the aneurysm with reconstruction of blood flow is still considered the gold standard. Several alternative and endovascular approaches are discussed.

Análise crítica das indicações e resultados do tratamento cirúrgico da doença carotídea

O tratamento da doença carotídea tem ganhado enfoque nos últimos anos, principalmente com o advento da técnica endovascular, que defende o emprego da angioplastia e stent de carótida (CAS), principalmente em pacientes considerados de "alto risco" para a endarterectomia carotídea (ECA). Através da revisão bibliográfica, analisamos os resultados do tratamento da lesão carotídea em ambas as técnicas, realizando comentários embasados na experiência pessoal e nos dados da literatura, sobretudo nos pacientes de alto risco. Até o presente momento, não há evidência e justificativa para o emprego da CAS em larga escala nos pacientes com doença carotídea, inclusive nas situações de alto risco, tais como nos octogenários. No entanto, acreditamos que a CAS possa ser um coadjuvante no tratamento de pequeno número de pacientes com lesão carotídea (até 4% dos casos), como na presença de pescoço hostil, radioterapia prévia e alguns casos de estenose carotídea alta. Quando realizada com os cuidados técnicos necessários, a ECA ainda continua a melhor opção terapêutica aos doentes com lesão carotídea.

Mandibular Subluxation for Distal Cervical Exposure of the Internal Carotid Artery

INTRODUCTION

Surgical access to the distal segment of the cervical internal carotid artery (ICA) is a challenge because of the limited exposure imposed by bony structures and concern regarding cranial nerve and major vasculature injury. Our objective is to quantify the additional exposure of the distal cervical ICA obtained with mandibular subluxation (MS) compared with maneuvers that do not mobilize the mandible.

METHODS

Thirty dissections of the cervical ICA and common carotid artery bifurcation were performed on fresh cadavers. The length of the ICA exposure was measured from the carotid bifurcation to the most distally exposed ICA after sectioning the posterior belly of the digastric and stylohyoid muscles, removal of the styloid process, and MS.

RESULTS

After MS, a 5.52 +/- 1.00 cm mean exposure of the cervical ICA was obtained. Comparison between the second and third measures revealed an average additional exposure of the ICA of 0.77 cm, corresponding to an additional 16.2% (P < .001). Neck length, sex, and age showed no correlation with the ICA exposure.

CONCLUSION

MS provided an additional exposure of the distal segment of the cervical ICA and may be useful in selected cases to improve access. However, staged maneuvers should be used, and the need for MS depends on the level and extension of the lesion.

Surgical Management of Lesions of the Internal Carotid Artery Using a Modified Fisch Type A Infratemporal Approach

OBJECTIVE

To report seven cases of vascular repair of the internal carotid artery (ICA) using a modified Fisch type A infratemporal approach and a venous grafting.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary care center.

PATIENTS

We have analyzed the clinical presentation, paraclinical assessment, and postoperative results regarding the vascular repair and the facial and auditory function from seven consecutive patients. All patients have been operated on by a multidisciplinary team of ENT and vascular surgeons.

RESULTS

The study includes four men and three women, aged from 21 to 62 years old. Six patients suffered from vascular traumatic injury after motor vehicle accident (n = 5) or cervical manipulation (n = 1) and one patient presented an atheromatous stenosis. All benefited from a vascular repair with a venous grafting through a modified Fisch Type A infratemporal approach. No death and no new stroke were noted (mean follow-up, 34 mo). The postoperative angiographies showed six functional grafts and one asymptomatic thrombosis. Six immediate postoperative facial palsy occurred but recovered to Grade I or II within 6 months. There was one traumatic injury of the facial nerve and one postoperative anacusis. For the six other patients, the reconstitution of the external auditory canal and ossicular chain allowed to limit the hearing loss to a mean air-bone gap of 22.5 dB (range, 15-35 dB).

CONCLUSION

The lesions of the intrapetrous aspects of the ICA remain the subject of debates regarding the indication for a vascular repair. For young or in good health patients, the infratemporal approach provides a safe and reliable access to the horizontal segment of the ICA, offering to the vascular surgeons optimal conditions for the vascular repair.

Exposure of the cervical internal carotid artery: surgical steps to the cranial base and morphometric study

OBJECTIVE

Several studies have reported on approaches to increase exposure of the distal cervical internal carotid artery (ICA), but these studies have neither systematically addressed the anatomic aspects nor quantified the additional exposure of each maneuver. We describe surgical steps to expose the ICA region, quantify the additional exposure of each operative step, and discuss ways to minimize surgical morbidity.

METHODS

The ICA was exposed in 10 formalin-fixed cadaveric heads using the following four steps: 1) anterior sternocleidomastoid approach, 2) retroparotid dissection and division of the digastric muscle, 3) section of the styloid apparatus, and 4) mandibulotomy. After completion of each step, the most distal level of ICA exposure was marked with a hemoclip and segment lengths were measured between each clip.

RESULTS

Sectioning of the digastric muscle and sectioning of the styloid apparatus provided the most significant exposure of the ICA (14.15 and 15.08 mm, respectively) with minimal risks. Mandibulotomy added 10.20 mm in length and 20.65 degrees in width, but is a maneuver that must be weighed against the heightened risk of morbidity.

CONCLUSION

Surgical exposure of the distal cervical ICA is associated with relatively high morbidity that increases with higher levels of exposure. Staged maneuvers have been shown to increase ICA exposure, especially in our systematic approach. The number of steps required varies depending on the level of lesion. Complete understanding of the surgical anatomy is essential to minimize surgical morbidity and to develop surgical expertise.

Patient selection for carotid stenting versus endarterectomy: A systematic review

Carotid artery stenting has emerged as an alternative to carotid endarterectomy for the treatment of severe extracranial carotid stenosis in patients with anatomic or clinical factors that increase their risk of complications with surgery, yet there remains a substantial amount of variability and uncertainty in clinical practice in the referral of patients for stenting vs endarterectomy. By undertaking a thorough review of the literature, we sought to better define which subsets of patients with "high-risk" features would be likely to preferentially benefit from carotid stenting or carotid endarterectomy. Although only a single randomized trial comparing the outcomes of carotid stenting with distal protection and endarterectomy has been completed, a wealth of observational data was reviewed. Relative to endarterectomy, the results of carotid stenting seem favorable in the setting of several anatomic conditions that render surgery technically difficult, such as restenosis after prior endarterectomy, prior radical neck surgery, and previous radiation therapy involving the neck. The results of stenting are also favorable among patients with severe concomitant cardiac disease. Carotid endarterectomy, alternatively, seems to represent the procedure of choice among patients 80 years of age or older in the absence of other high-risk features. Overall, existing data support the concept that carotid stenting and endarterectomy represent complementary rather than competing modes of therapy. Pending the availability of randomized trial data to help guide procedural selection, which is likely many years away, an objective understanding of existing data is valuable to help select the optimal mode of revascularization therapy for patients with severe carotid artery disease who are at heightened surgical risk.

Usefulness of transcervical approach for surgical treatment of hypoglossal schwannoma with paraspinal extension: case report

BACKGROUND

Usefulness of transcervical approach to hypoglossal schwannoma with paraspinal extension is described herein.

CASE DESCRIPTION

A 54-year-old woman presented with gradually worsening left hypoglossal nerve palsy. The findings were of a tumor lying in the left hypoglossal canal and paraspinal region and were consistent with hypoglossal schwannoma. Subtotal intracapsular removal of the tumor was performed via transcervical approach. The symptoms improved, and no additional symptoms were noted.

CONCLUSION

The transcervical approach and intracapsular removal of the tumor under electrophysiological monitoring provided for successful minimally invasive surgery in this case of hypoglossal schwannoma.

Surgical anatomy of the cervical carotid artery for carotid endarterectomy

Carotid endarterectomy (CEA) is the main treatment for atherosclerotic plaque of the cervical internal carotid artery. The surgical anatomy of the carotid arteries was studied in the carotid triangle of 49 cadavers. The carotid bifurcation was located at the level of the lower third of C-3. The superior thyroid artery arose from the anterior wall of the external carotid artery in 70% of specimens and from the distal portion of the common carotid artery in 30%. The lingual artery arose as a separate trunk between the origins of the superior thyroid and facial arteries in 81% of specimens, with the facial artery from a common trunk in 18%, and with the superior thyroid artery in 1%. The occipital artery arose from the posterior aspect of the external carotid artery above the level of origin of the facial artery in 57% of specimens, between the origins of the facial and lingual arteries in 32%, and below the origin of the lingual artery in 11%. The origin of the occipital artery was positioned low and the distal portion of the occipital artery was crossed by the hypoglossal nerve in 20%. The ascending pharyngeal artery arose from the posterior wall of the external carotid artery above the level of origin of the lingual artery in 66% of specimens, below the origin of the lingual artery in 9%, from the proximal portion of the occipital artery in 19%, from the carotid bifurcation in 2%, and from the internal carotid artery in 2%. The branches of the external carotid artery are the key landmarks for adequate exposure and appropriate placement of cross-clamps on the carotid arteries. It is necessary to understand the surgical anatomy of the carotid arteries to carry out successful removal of plaque and minimize postoperative complications in a bloodless surgical field.

Head and neck extension-fixation with a head frame for exposure of the distal internal carotid artery in carotid endarterectomy--technical note

Adequate exposure of the distal internal carotid artery (ICA) for carotid endarterectomy may be difficult to achieve because of the position of the mandible and associated soft tissues. A simple yet effective use of a head frame is described to gain several centimeters of exposure of the distal ICA. The patient's head and neck are fixed in an extension position using a radiolucent head frame. Nasotracheal intubation and secure taping of the chin are also employed to keep the mouth closed and to prevent the mandible from spontaneously hanging down. The head frame tightly fixes the patient's neck, so the mandible does not disturb the surgical field throughout the operation. This simple method maximizes exposure of the distal ICA. The radiolucent head frame also enables intraoperative angiography to confirm the patency of the ICA and the absence of flap formation. This simple technique is useful for exposing the distal ICA.

Surgical approach to the third area of the internal carotid artery through vertical osteotomy of the mandibular ramus: case report

Internal carotid artery (ICA) reparative techniques are nowadays widely standardized in traumatic as well as degenerative pathological conditions; therefore, the greatest difficulty encountered in the treatment of lesions at the expense of the most distal segment of the ICA is not a result of the application of these techniques as much as the difficulty in obtaining adequate exposure of the vessel and a sufficiently wide surgical field. In the past, lesions localized more toward the skull were considered to be surgically unreachable. During the last 20 years, however, various techniques have been suggested and attempted for the exposure of this difficult area. This article suggests a type of approach already carried out by the Department of Maxillofacial Surgery of the University of Rome "La Sapienza" in collaboration with the II Department of Vascular Surgery of the same university, which offers the advantage of being of simple and rapid execution with minimum repercussions on the intrasurgical time required and guarantees an excellent exposure of the most distal tract of the ICA with an adequate widening of the surgical field.

Reconstructive surgery of the extracranial arteries

The first carotid endarterectomy (CEA) is usually accredited to Eastcott who reported in 1954 the successful incision of a diseased carotid bulb with end-to-end anastomosis of the internal carotid artery (ICA) to the common carotid artery (CCA). During the following years surgeons were quick to adopt and improve the intuitively attractive procedure. But by the early to mid 1980s several leading neurologists began to question the growing number of CEAs performed at that time. Six major CEA trials were then designed which are now completed or nearing completion. Most conclusive data are available from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) for symptomatic carotid disease, and from the Asymptomatic Carotid Atherosclerosis Study (ACAS) for asymptomatic carotid disease. The key result of these studies is that CEA is beneficial to high grade symptomatic and asymptomatic carotid stenosis. While the benefit in symptomatic disease is clear, it may be negligible in asymptomatic patients suffering from other medical conditions, the most important being coronary artery disease. Since the conclusions from the different studies vary significantly, guidelines and recommendations with regard to CEA have been issued by a number of interest groups, so-called consensus conferences. The best known guidelines are published by the American Heart Association (AHA). However, the practice of interest groups to issue guidelines is currently being criticized, the main reason being that interest groups have different ideas and all claim the right to issue guidelines. At present we recommend CEA for symptomatic high-grade stenosis in patients without significant coincident disease. With regard to asymptomatic stenosis we suggest surgery to otherwise healthy patients if the stenosis is very narrow or progressive. Preoperative evaluation has changed over the years. Currently we recommend duplex sonography in combination with intra- and extracranial magnetic resonance angiography (MRA). Concurrent coronary artery disease is a major consideration in the perioperative management, and the use of a specific algorithm is recommended. Surgery is performed under general anaesthesia with intraoperative monitoring such as electroencephalography (EEG) and transcranial Doppler (TCD). A temporary intraluminal shunt is used selectively if after cross-clamping the flow velocity in the middle cerebral artery (MCA) falls to below 30 to 40% of baseline. For years we employed routine barbiturate neuroprotection during cross-clamping. At the present time we use barbiturate selectively, if the flow velocity in the MCA falls to below 30 to 40% of baseline and if the use of a temporary intraluminal shunt is not possible due to difficult anatomic conditions. The reason to abandon systematic barbiturate protection was to accelerate recovery from anaesthesia. Our patients are monitored overnight on the ICU or a surveillance unit. Routine hospitalization after surgery is 5 to 7 days with a control duplex sonography being performed prior to discharge. A number of details with regard to surgical technique and perioperative management are a matter of discussion. Our surgical routine is described here step by step. Such management resulted in 6 major complications among the 402 cases with 4 of cardiopulmonary and 2 of cerebrovascular origin. For the future we can expect the development of percutaneous transluminal techniques competing with standard carotid endarterectomy. At the present time several comparative studies are under way. Irrespective of the technical approach to treat carotid stenosis, several other issues have to be clarified before long. One of the major unresolved items is the timing of treatment after completed stroke. In this regard prospective trials need to be performed. Although numerically not as important as carotid stenosis, vertebral artery (VA) and subclavian artery (SA) stenoses are more and more accepted as indication for surgical

Carotid angioplasty and stenting: new horizons

Advances in technology have made it possible for lesions that affect the carotid artery, both extra-and intracranially, to be treated by endovascular means. Depending upon the type and location of the pathology, as well as the existing comorbidities in any given patient, angioplasty and stenting may be considered an alternative to traditional methods of revascularization. In fact, in some instances, endovascular therapy may be the procedure of choice. For patients whose lesions can be treated either surgically or endovascularly, future randomized trials will help define the role of each type of procedure.

Mandibular subluxation for distal internal carotid exposure: technical considerations

PURPOSE

Carotid endarterectomy (CEA) has become one of the most commonly performed vascular procedures, because of the beneficial outcome it has when compared with medical therapy alone and because of the anatomic accessibility of the artery. In cases of distal carotid occlusive disease, high cervical carotid bifurcation, and some reoperative cases, access to the distal internal carotid artery may limit surgical exposure and increase the incidence of cranial nerve palsies. Mandibular subluxation (MS) is recommended to provide additional space in a critically small operative field. We report our experience to determine and illustrate a preferred method of MS.

METHODS

Techniques for MS were selected based on the presence or absence of adequate dental stability and periodontal disease. All patients received general anesthesia with nasotracheal intubation before subluxation. Illustrations are provided to emphasize technical considerations in performing MS in 10 patients (nine men and one woman) who required MS as an adjunct to CEA (less than 1% of primary CEAs). Patients were symptomatic (n = 7) or asymptomatic (n = 3) and had high-grade stenoses demonstrated by means of preoperative arteriography.

RESULTS

Subluxation was performed and stabilization was maintained by means of: Ivy loop/circumdental wiring of mandibular and maxillary bicuspids/cuspids (n = 7); Steinmann pins with wiring (n = 1); mandibular/maxillary arch bar wiring (n = 1); and superior circumdental to circummandibular wires (n = 1). MS was not associated with mandibular dislocation in any patient. No postoperative cranial nerve palsies were observed. Three patients experienced transient temporomandibular joint discomfort, which improved spontaneously within 2 weeks.

CONCLUSION

Surgical exposure of the distal internal carotid artery is enhanced with MS and nasotracheal intubation. We recommend Ivy loop/circumdental wiring as the preferred method for MS. Alternative methods are used when poor dental health is observed.

Accuracy of duplex ultrasound in evaluating carotid artery anatomy before endarterectomy

PURPOSE

Anatomic features, such as a high carotid bifurcation (< 1.5 cm from the angle of the mandible), excessive distal extent of plaque (> 2.0 cm above the carotid bifurcation), or a small diameter (< or = 0.5 cm) redundant or kinked internal carotid artery can complicate carotid endarterectomy. In the past, arteriography was the only preoperative study capable of imaging these features. This study assessed the ability of duplex ultrasound to evaluate their presence before surgery.

METHODS

A consecutive series of 20 patients who underwent 21 carotid endarterectomies had preoperative duplex ultrasound evaluations of these anatomic features. These evaluations were correlated with operative measurements from an observer blinded to the duplex findings.

RESULTS

The mean difference between duplex and operative measurements for the distance between the carotid bifurcation and the angle of the mandible, the distal extent of plaque, and the internal carotid artery diameter was 0.9 cm, 0.3 cm, and 0.8 mm, respectively. The correlation coefficient between the two methods was 0.86, 0.75, and 0.59, respectively. Duplex ultrasound predicted a high carotid bifurcation, excessive distal extent of plaque, or a redundant or kinked internal carotid artery with 100% sensitivity (p < 0.05, p < 0.01, and p < 0.001, respectively). The sensitivity of duplex ultrasound in predicting a small internal carotid artery diameter was 80%. The specificity of duplex ultrasound for predicting excessive distal extent of plaque, small internal carotid artery diameter, high carotid bifurcation, and a coiled or kinked carotid artery was 92%, 56%, 100%, and 100%, respectively.

CONCLUSION

Duplex ultrasound can predict the presence of anatomic features that may complicate carotid endarterectomy. Preoperative duplex imaging of these features may be helpful in patients who undergo carotid endarterectomy without preoperative arteriography.