Technical issues in carotid artery surgery 1995

Diagnosis and Operative Management of Carotid Endarterectomy in Patients with Twisted Carotid Bifurcation

Although carotid endarterectomy (CEA) is an established procedure, technical modifications are required when anatomical features are unusual. The present study aimed to determine the characteristics of diagnostic features, surgical management, and outcomes of patients with a twisted carotid bifurcation (TCB). We assessed 108 consecutive patients by cervical carotid echography (CCE) and black-blood magnetic resonance imaging (BB-MRI) before they underwent 115 CEA procedures. We classified carotid bifurcation (CB) anatomy based on anteroposterior findings of the internal carotid artery (ICA) and external carotid artery (ECA) determined by cerebral or three-dimensional computed tomographic angiography as follows. The ICA and ECA ran laterally and medially, respectively, in Type 1, overlapped in Type 2, and the ICA and ECA ran medially and laterally, respectively, in Type 3. We also classified the patients according to whether or not they had a TCB and compared their diagnostic findings, clinical characteristics, and surgical outcomes. The numbers of patients with Types 1, 2, and 3 were 74 (64.4%), 32 (27.8%), and 9 (7.8%), respectively, and 13 (11.3%) with a TCB included four patients with Type 2 and all nine patients with Type 3. The appearance of Type 3 differed from that of the other two types on CCE and BB-MR images. After correcting the anatomical location of a TCB, surgical duration and adverse event rates did not significantly differ between patients with and without a TCB. Patients with a TCB could safely undergo CEA after correcting the ICA to the normal position.

Analysis of twisted internal carotid arteries in carotid endarterectomy

Background:

The twisted carotid artery is a variant, in which the internal carotid artery (ICA) courses medially to the external carotid artery. Due to the sparse descriptions in the literature, we, here, report our experience with cases of carotid endarterectomy (CEA) for twisted carotid artery and its clinical features.

Methods:

Fifty-seven consecutive CEA-treated patients were evaluated, and the twist angle was measured on the source images of axial slices of computed tomography angiography (CTA).

Results:

Eight male patients (14.2%) demonstrated a twisted right ICA (mean age, 77.0 ± 2.6 years; and mean stenosis, 66.9% ± 19.9%). The mean twist angle was 30.1° ± 17.9°, while the normal ICA is angled at −23.0° ± 12.3°. No statistical differences in the distribution of coexisting diseases were found between the normal and twisted ICA cases. CEA was successfully performed with the correction of the carotid position in all cases; however, significant position correction was not observed in the postoperative evaluation. Right-side dominancy (P = 0.045) and prolonged clamping time (P = 0.053) were observed in the twisted cases.

Conclusion:

Twisted ICA was preferentially found in the right ICA and men. CEA of the twisted ICA was safely performed with appropriate head rotation and wider longitudinal skin incision than usual without a significant increase in the operative time. CTA is useful for preoperative evaluation. This specific variation should be considered by the neurosurgeon involved in the evaluation and treatment of carotid stenoses.

The Use of the Carotid Sheath as a Rotation Anchor to Detect an Anomalous Ascending Pharyngeal Artery in Carotid Endarterectomy

Carotid endarterectomy (CEA) requires complete control of the blood backflow. An anomalous ascending pharyngeal artery (AphA) has been reported to result in incomplete control of the blood flow during CEA. Here, we present a case of symptomatic right internal carotid stenosis for which CEA was performed. An anomalous AphA was confirmed based on its origin from the distal internal carotid artery (ICA) on 3-dimensional rotational angiography (3DRA). The anomalous AphA arose near the distal end of the plaque, and the origin of the AphA was located in the dorsal wall of the ICA, hidden from the surgical view. The origin of the AphA was detected with rotation of the ICA within the carotid sheath (CS). Intraoperatively, the blood flow from the AphA was completely controlled with clamping of the origin of the AphA. We emphasize the importance of the 3DRA to detect an anomalous AphA and propose the use of the CS as an anchor to rotate the ICA for optimizing the surgical view behind the ICA. This simple surgical technique facilitates to detect and clamp an anomalous AphA arising from the ICA.

Lateral Position of the External Carotid Artery: A Rare Variation to Be Recognized During Carotid Endarterectomy

BACKGROUND

External carotid artery (ECA) positioned laterally to the internal carotid artery (ICA) at the level of the common carotid artery (CCA) bifurcation is occasionally encountered during carotid endarterectomy (CEA). This study aimed to determine the frequency of this phenomenon and provide technical tips for performing CEA.

METHODS

The study included 199 consecutive patients (209 carotid arteries) who underwent CEA at Otaru Municipal Medical Center in 2007-2014. The position of the ECA with respect to the ICA at the CCA bifurcation was preoperatively rated as either lateral or normal, using three-dimensional computerized tomographic angiography (3-D CTA) anteroposterior projections. Postoperative diffusion-weighted images (DWIs), and postoperative 3-D CTA images were reviewed.

RESULTS

Among the 209 carotid arteries with atherosclerosis, 11 instances (5.3 %) of lateral position of the ECA were detected in 11 patients. Ten of these arteries (91 %) were right-sided (odds ratio 11.1; 95 % confidence interval 1.38-88.9). Wider longitudinal exposure of the arteries was used during CEA, and the CCA and ECA were rotated clockwise or counter clockwise. The ICA lying behind the ECA along the surgical access route was then pulled out laterally and moved to the shallow surgical field. Cross-clamping, arteriotomy, plaque removal, and wall suturing were performed as usual. No cerebral infarcts were detected on postoperative DWIs, and 3-D CTA revealed no CCA and ICA kinking.

CONCLUSIONS

Lateral position of the ECA is not extremely rare in patients undergoing CEA for atherosclerosis and may be a congenital variation, although this is still controversial. CEA can be performed safely if the arteries from the CCA to the ICA are rotated, and the ICA is moved to the shallow surgical field under wider longitudinal exposure. Although no postoperative cerebral infarcts were detected, the risk of artery-to-artery embolism resulting from artery repositioning prior to plaque removal should be taken into consideration.

Comparison of intermediate vs subcutaneous cervical plexus block for carotid endarterectomy

BACKGROUND

Carotid endarterectomy surgery can be performed under regional anaesthesia alone or under general anaesthesia. However, there are several types of regional block available and reported complication rates after superficial cervical plexus blocks are significantly lower than deep blocks. It is not known if subcutaneous and intermediate blocks are equally effective, although anatomical evidence suggests that the latter (where the injectate diffuses below the deep cervical fascia) might provide superior quality of intraoperative anaesthesia.

METHODS

Forty-four patients were randomized to receive either subcutaneous or intermediate cervical plexus blocks for carotid endarterectomy. The primary endpoint was supplemental lidocaine requirement during surgery. Secondary outcome measures included: total amount of fentanyl administered during surgery, recall of pain scores during surgery, complications, and patient and surgeon satisfaction.

RESULTS

There was no statistically significant difference for median (range) lidocaine supplementation between the subcutaneous and intermediate groups 65 (20-170) mg vs. 85 (30-345) mg, respectively; P=0.31. There were no statistical differences in the secondary outcome measures and no major complications during the study.

CONCLUSIONS

Intermediate and subcutaneous cervical plexus blocks are equally effective for carotid endarterectomy. This study adds to the body of evidence supporting the safe use of superficial blocks for this type of surgery.

An audit of carotid endarterectomy for internal carotid artery disease at Dunedin Hospital

Carotid endarterectomy, mostly for symptomatic internal carotid artery stenosis, has been successfully performed in both the vascular and neurological surgery units at Dunedin Hospital. This study was performed to compare our results with those of the North American Symptomatic Carotid Endarterectomy Trial and the European Carotid Surgery Trial. The 30-day perioperative morbidity and mortality rate was 4.3% (1.2% < 95% Cl > 7.4%) which compares favourably with an estimated upper limit of 5.5% based on recent trial reports. The present study highlights the difficulty in modelling local clinical practice on results of major trials when standards of patient evaluation and surgical skill may differ from those of the large studies. To justify generalization of indications for intervention based on the multicentre trials, there must be continual monitoring of local surgical results, and standardized use of diagnostic investigations.

Retraction suture technique for carotid endarterectomy

We propose a retraction suture technique as a safe and effective surgical procedure for carotid endarterectomy. Retraction sutures of the skin flap, the carotid sheath and the adventitia of the carotid artery are used to obtain an adequate operative field without the use of retractors or assistants. This technique is useful for carotid endarterectomy.

Fixative method of carotid shunt using a Sugita's fenestrated aneurysm clip as a device in carotid endarterectomy technical note

BACKGROUND

Difficulty for distal exposure of the ICA is sometimes encountered during CEA. A carotid shunt is used to maintain sufficient cerebral blood flow during CEA but requires fixative materials, such as a string or a metallic ring, which often restrict the operative field, especially that of the distal ICA.

METHODS

Here, we describe a novel technique for carotid shunt fixation using a unique fixative device in CEA. In the method presented here, the carotid shunt is fixed with an inflated balloon and a conventional vascular tourniquet proximally, but distal fixation is achieved using a Sugita's fenestrated clip that catches the mid portion of the carotid shunt and surrounding tissue.

RESULTS AND CONCLUSION

The device prevents the distal carotid shunt slipping out of the distal ICA. The present method allows mobilization of the shunt position during CEA and facilitates far-distal exposure of the ICA.

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.

The use of evoked potentials in intraoperative neurophysiologic monitoring

Although not universally adopted, the growing body of literature provides strong evidence of the clinical utility of IOM in a variety of cerebrovascular surgical and endovascular procedures. The Therapeutics and Technology Subcommittee of the American Academy of Neurology and Fisher et al concluded that the following are useful and noninvestigational: 1. EEG, compressed spectral array, and SSEP in CEA and brain surgeries that potentially compromise cerebral blood flow, 2. BAEP and cranial nerve monitoring in surgeries performed in the region of the brainstem or inner ear, 3. SSEP monitoring performed for surgical procedures potentially involving ischemia or mechanical trauma of the spinal cord. They also came to the conclusion that although promising, motor EPs and visual EPs are still investigational. Further investigation, especially in the area of outcomes research and cost-effectiveness, is required before IOM can become standard practice.

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

Treatment of carotid tandem stenosis by combined carotid endarterectomy and balloon angioplasty: technical case report

OBJECTIVE AND IMPORTANCE

Cervical internal carotid artery disease associated with high-grade carotid siphon stenosis poses a therapeutic challenge. This report describes the combination therapy of carotid end-arterectomy and intraoperative transluminal balloon angioplasty of the carotid siphon.

CLINICAL PRESENTATION

A 67-year-old man sustained repeated left hemispheric and retinal transient ischemic attacks. Results of a diagnostic examination, including angiography, disclosed a 70% ulcerative stenosis of the left extracranial internal carotid artery as well as a 90% stenosis of the left intracavernous carotid artery. The decision was made for combined open and endovascular therapy.

INTERVENTION

After standard endarterectomy, an introducer for the dilation catheter was placed into the common carotid artery before final closure of the arteriotomy and recirculation. Under intraoperative fluoroscopy, a 3-mm dilation balloon was navigated into the carotid siphon stenosis and inflated several times. A 30% residual stenosis in the carotid siphon was obtained as a final result. The intervention was completed without complications. No further neurological symptoms were observed during the follow-up period of 30 months.

CONCLUSION

Carotid endarterectomy, combined with intraoperative transluminal angioplasty of carotid siphon stenosis, is a feasible procedure for selected patients with carotid tandem stenosis.

Comparison of near-infrared spectroscopy and somatosensory evoked potentials for the detection of cerebral ischemia during carotid endarterectomy

BACKGROUND AND PURPOSE

We sought to assess the clinical value of regional cerebral saturation (rSO2) obtained by means of the cerebral oximeter INVOS 3100A (Somanetics) in comparison to monitoring of somatosensory evoked potentials (SEP) for the reliable detection of severe cerebral ischemia requiring shunt placement in the individual patient undergoing carotid surgery under general anesthesia.

METHODS

In 317 patients undergoing reconstructive surgery on the internal carotid artery, simultaneous recordings of SEP and rSO2 were obtained throughout the operation.

RESULTS

All 287 patients with preserved cortical SEP remained neurologically intact. Shunt placement was performed in 27 patients (9%) after flattening of cortical SEP during cross-clamping of the internal carotid artery. A stable rSO2 value just before cross-clamping and the lowest value after cross-clamping were registered, and the decrease was calculated. A statistically significant (P<0.01) decrease of rSO2 after cross-clamping could be found in patients without (64.9+/-8.3% to 60.9+/-9.9%) as well as in patients with consecutive loss of cortical SEP (65.8+/-9.1% to 56.1+/-13.4%). The difference of the decrease of rSO2 in both groups was highly significant (6.9+/-9.0% versus 15.6+/-14.0%; P<0.001). However, substantial interindividual variability of rSO2 and derived change of rSO2 did not allow the definition of a threshold value indicating need of shunt placement.

CONCLUSIONS

The reliability of SEP for the detection of clamp-related hypoperfusion has been reaffirmed. As long as rSO2 threshold values indicating critical cerebral ischemia are not defined, therapeutic interventions based on monitoring with the cerebral oximeter INVOS 3100A are not justified.

Extracranial-intracranial high-flow bypass using the radial artery between the vertebral and middle cerebral arteries. Technical note

Carotid ligation and vascular reconstruction following radical neck dissection were required in a patient with carotid artery rupture associated with an infected salivary fistula. An extracranial-intracranial high-flow bypass was performed using a radial arterial graft between the V3 segment of the vertebral artery and the M2 segment of the middle cerebral artery. Postoperative angiograms confirmed sufficient blood flow through the bypass graft into the ipsilateral internal carotid arterial system. No clinical signs of ischemia were observed postoperatively. This V3-M2 bypass procedure appears to be an effective means of controlling catastrophic bleeding from a ruptured carotid artery, thus allowing the wound to heal completely.

Optimal timing of hemodilution for brain protection in a canine model of focal cerebral ischemia

BACKGROUND AND PURPOSE

Hemodilution is known to ameliorate the effects of focal ischemia when used shortly after cerebral arterial occlusion; however, it remains to be proved whether hemodilution will be effective when used at more clinically relevant times, ie, with some delay between the onset of ischemia and initiation of therapy.

METHODS

Thirty-two dogs were selected for inclusion in this study. Cerebral infarction was induced by permanent occlusion of the middle cerebral and the azygos anterior cerebral arteries. The animals were allocated to 1 of 4 groups of eight animals each: arterial occlusion without hemodilution (group 1); hemodilution immediately after occlusion (group 2); hemodilution 3 hours after occlusion (group 3); and hemodilution 6 hours after occlusion (group 4). Isovolemic hemodilution to a hematocrit of 30% was performed. The animals were killed 6 days after induction of ischemia, and the infarct size was determined.

RESULTS

Groups 2 and 3 showed significant reduction of infarct size (P < .0001) when compared with group 1. The neurological grade of group 3 on postoperative days 4, 5, and 6 was significantly better than those of groups 1 and 4 (P < .01). Group 4 showed a significant increase in the incidence of hemorrhagic infarction when compared with groups 1 and 2 (P < .01).

CONCLUSIONS

The current study indicates that hemodilution administered as much as 3 hours after ischemia is effective in reducing infarct size and improving neurological status. When administered 6 hours after ischemia, hemodilution is not helpful and may be harmful.