Given the critical importance of full exposure of the carotid bifurcation and access to the non-diseased internal carotid artery beyond the stenotic plaque, CEA has traditionally been performed through full-length neck incisions, extending from just inferior to the mastoid process to just above the suprasternal notch and running parallel to the anterior border of the sternocleidomastoid [4,13]. Such extensive incisions may be unnecessary, particularly in patients with a relatively low carotid bifurcation or with a localized diseased segment . Consequently, several cohort studies have demonstrated that shorter longitudinal incisions are technically feasible [2,6,8]. Such “mini” longitudinal incisions are purported to offer improved cosmesis. Whereas one group has reported reductions in the length of hospital stay and CNI rates, others have reported no difference in complication (mortality, stroke, or nerve injury) rates with shorter incisions compared with the traditional access method [2,6,8]. Remarkably, no information on a universally accepted threshold size which classifies an incision as ‘small’ has been defined in the literature. Different groups have suggested that traditional access incisions can range in length from >7 cm to as long as 17.5 cm [6,8]. Conversely, “mini” longitudinal incisions have been described as those that are <5 to 7 cm in length, with some studies describing successful CEA through longitudinal incisions <2.5 cm in length [2,3,6,8].
In an attempt to shorten the length of the incision, re-orientation of the incision in a transverse or oblique direction in line with the skin creases of the neck (and therefore Langer’s lines) has further improved cosmesis [5,9,12,14–17]. Concerns with transversely oriented incisions in CEA were related to the lack of enhanced exposure through the incision extension in instances wherein either the location of the carotid bifurcation or the extent of disease is misjudged preoperatively and to increased difficulty with shunt deployment compared to that through longitudinally oriented incisions [3,13]. Proponents of the technique advice that with the increase in the subplatysmal flap, the use of self-retaining retractors as well as natural laxity of the neck skin is generally possible to gain additional cephalad or caudal exposure as needed [12,14,18]. Recent reports describe the use of specialized ring retractor systems in enabling mini-incision CEA [19,20]. In our practice, a pair of self-retaining retractors (such as a Travers retractor) is used, which enables re-orientation of the subplatysmal portion of the wound to a horizontal direction, thereby achieving a similar exposure to that with a longitudinal skin incision.
Concerns with transversely oriented incisions appear to have not been reported in several nonrandomized studies and cohort studies demonstrating successful CEA through such incisions with postoperative hematoma, mortality, and stroke rates, without different longitudinal incisions [3,5,12,14,17]. However, while authors have described improved cosmesis based on both subjective and objective wound assessment parameters with transverse incisions, the benefits of a transverse incision in terms of CCN injuries are more controversial [3,12,18]. Therefore, although one nonrandomized study reported a higher risk of marginal mandibular nerve dysfunction with longitudinal incisions, this has not been substantiated by others [3,12,14,18]. Indeed, one nonrandomized study reported a significantly higher rate of ipsilateral temporary vocal cord dysmotility with transverse incisions; however, this finding was significantly confounded in a retrojugular approach using transverse incisions compared with a ventrojugular approach using longitudinal incisions . A meta-analysis of risk factors for CNI after CEA found that expedited surgery and re-exploration for postoperative neurology or bleeding were associated with CNI, while the type of anesthesia, use of shunt, patch reconstruction, and re-do surgery were not . The analysis did not include the type of incision, and therefore as the anatomical first principles would indicate that a transverse incision should be associated with less CCN injury (in particular greater auricular nerve and transverse cervical nerve branches), this remains unproven .
It is noteworthy that while transverse-incision CEA has been utilized in the full spectrum of cases (symptomatic and asymptomatic cases, general and regional anesthesia, eversion endarterectomy and patch reconstruction), even proponents of a transverse incision acknowledge potential difficulties with adequate exposure and that in some nonrandomized comparisons, surgeons preferentially utilized a longitudinal incision in patients suspected with “difficult” situations (i.e., patients with high bifurcations or requiring re-do surgery) [13,14].
Our study demonstrates the applicability of targeted “mini” transverse-incision CEA in consecutive patients, with outcomes equivalent to those of published series . We ascribe our success with the method, even in unfavorable patients (i.e., obesity, short necks, high bifurcations, and long plaque), to the accurate localization of the carotid bifurcation with CDUS that enables transverse incision to be appropriately sited. CDUS has been demonstrated to be an effective modality for visualizing the carotid anatomy [13,22]. Other reported methods used to assist in siting of the transverse incision over the bifurcation include the use of skin surface landmarks without adjunctive imaging, skin surface or vertebral level landmarks with adjunctive preoperative magnetic resonance angiography and combinations of imaging modalities (CTA, CDUS, and fluoroscopy) [5,9,12,18]. We would advocate caution in using skin surface landmarks due to the scope for variability according to body habitus, neck size, and coexistent pathology, such as degenerative cervical disc disease, whereas the use of cross-sectional (i.e., CTA or MRA) or otherwise ionizing (i.e., fluoroscopy) imaging modalities would seem to be an overly complex and inefficient use of resource given the effectiveness of CDUS.
We have described the use of continuous-wave hand-held Doppler (HHD) for quality assessment, i.e., the standard practice in our unit. It is accepted that there are numerous modalities available for intraoperative quality assessment (such as HHD, CDUS, angioscopy, and angiography), and HHD, although inexpensive, is operator dependent and does not allow visualization of defects; therefore, quantification of blood flow velocity has limitations . However, there remains no universally accepted consensus on the optimal assessment modality, and indeed, recent published series still describe a lack of any form of quality assessment .
Limitations of this study include a small sample size and its retrospective nature. However, patients had their surgery performed by one surgeon in one surgical unit, thus removing surgical technique as a potential confounder. Because “mini” transverse-incision CEA is routinely performed in our practice, we did not a have a CEA cohort with longitudinal incisions for comparison; we have instead benchmarked our outcomes against previously published series. It is acknowledged that this is a further limitation and that comparisons against a historical cohort of longitudinally sited incisions would have increased the power of this study. Any retrospective study will be subject to selection bias, and consequently the best way to compare transverse incision with longitudinal incision CEA would be within a well-designed randomized controlled trial. Finally, although CNI examination was performed in accordance with descriptions from published series (and was performed pragmatically as a part of standard postoperative care assessed by the operating team), it is acknowledged that the detection of clinical signs can vary according to observer, and consequently examination performed by specialists such as neurologists may have yielded different results.