Cook-Swartz Implantable Doppler Research Articles

Complications related to the Cook-Swartz implantable Doppler probe use in head and neck microvascular reconstruction: a systematic review.

Vascular perfusion research has been dedicated to identify inexpensive, effective, and easy to use methods to assess free flap perfusion for both buried and non-buried flaps. Systematic review of complications in patients underwent Head and Neck microsurgical reconstruction and vascular implantable Doppler monitoring. Sixteen articles were included for qualitative analysis. 2535 (92.2%) patients received IDP monitorization. Venous thrombosis was the most common vascular complication effecting 28 (1.1%). Regarding complications potentially related to the use of the IDP, just one study described the presence of granuloma formation along the suture line in 2 (0.07%) patients. Our findings indicated that Cook-Swartz IDP will represents a safe and effective device for FF monitoring in HN reconstructive micro-surgery. A detailed prospective registration of the results and complications related to the use of IDP remains mandatory to precisely estimate results, cost, and complications.

Postoperative neck pain associated with an implantable microvascular ultrasonic Doppler: a case report

Microvascular reconstruction in the head and neck has enabled the transfer of large amounts of tissue, and has improved functional and cosmetic outcomes for patients. Its success is primarily dependent on adequate perfusion, and though many methods have been used to monitor the circulation of flaps, the Cook-Swartz implantable Doppler has gained favour with surgeons and nursing staff. We present the unusual case of a patient who had developed recurrent infection and pain that was associated with its use.

The Efficacy of the Cook–Swartz Implantable Doppler in the Detection of Free-Flap Compromise: A Systematic Review and Meta-Analysis

Background Reducing free-flap failure rates is a key goal of any microsurgical unit. The Cook–Swartz implantable Doppler (CSD) can be used to monitor flap vascularity. We conducted a systematic review and meta-analysis to compare the efficacy of the CSD with clinical monitoring to prevent flap failure. Methods A comprehensive literature search was performed using MEDLINE, EMBASE, PsycINFO, EBSCO, the Cochrane Library, CINAHL, SCOPUS, SciELO, NHS evidence, and online clinical trial registers from 1966 until December 31, 2015. Studies comparing flap failure rates in the CSD and clinically monitored groups were considered. Screening and data extraction was performed by two independent researchers. Results Overall, eight articles met the inclusion criteria, involving 3,756 patients and 3,801 flaps. The average failure rate in the clinical group was 3.5% and in the Doppler group was 2.0%. A fixed effects meta-analysis was performed and found a reduced failure rate with the use of the CSD (odds ratio= 0.37 [0.21–0.64], p = 0.0005). Conclusion Deployment of the CSD can lower flap failure rates and has the potential to be a useful adjunct to clinical monitoring of free flaps. Further research is needed to confirm its benefits and refine its indications to optimize cost-effectiveness.

Cook-Swartz implantable Doppler: an ongoing UK analysis: arterial vs. venous placement: is there a difference?

Cook-Swartz implantable Doppler: an ongoing UK analysis: arterial vs. venous placement: is there a difference?

The efficacy of the Cook-Swartz implantable doppler in the detection of free flap compromise: A systematic review and meta-analysis

Background Reducing free-flap failure rates is a key goal of any microsurgical unit. The Cook–Swartz implantable Doppler (CSD) can be used to monitor flap vascularity. We conducted a systematic review and meta-analysis to compare the efficacy of the CSD with clinical monitoring to prevent flap failure. Methods A comprehensive literature search was performed using MEDLINE, EMBASE, PsycINFO, EBSCO, the Cochrane Library, CINAHL, SCOPUS, SciELO, NHS evidence, and online clinical trial registers from 1966 until December 31, 2015. Studies comparing flap failure rates in the CSD and clinically monitored groups were considered. Screening and data extraction was performed by two independent researchers. Results Overall, eight articles met the inclusion criteria, involving 3,756 patients and 3,801 flaps. The average failure rate in the clinical group was 3.5% and in the Doppler group was 2.0%. A fixed effects meta-analysis was performed and found a reduced failure rate with the use of the CSD (odds ratio= 0.37 [0.21–0.64], p = 0.0005). Conclusion Deployment of the CSD can lower flap failure rates and has the potential to be a useful adjunct to clinical monitoring of free flaps. Further research is needed to confirm its benefits and refine its indications to optimize cost-effectiveness.

Rationale for the use of the implantable Doppler probe based on 7 years’ experience

In head and neck microvascular reconstruction, a proportion of patients are at a higher risk of flap failure. These include salvage surgery after chemoradiotherapy, reconstruction for osteoradionecrosis and when difficulty is encountered in achieving flap perfusion intraoperatively. Several studies have shown that the Cook-Swartz Doppler (Cook Medical Inc, Bloomington, USA) enabled earlier detection of a compromised flap. We retrospectively reviewed microvascular reconstructions monitored with the Cook-Swartz implantable Doppler (2006–2012) and included patients’ characteristics, comorbidity (American Society of Anesthesiologists’ (ASA) grade), indication for operation, type of reconstruction, and indication for implantable Doppler. We also included details of surgical exploration, free flap salvage, and outcomes of flap salvage. These outcomes were compared with a group of low-risk patients (2005–2009) whose flaps were monitored clinically. A total of 75 free flaps in 73 patients were monitored with the implantable Doppler: 40 (53%) were in cases which required reconstruction following previous surgery/radiotherapy or flap perfusion difficulties, 10 (13%) buried flaps, 13 (17%) as routine flap monitors and 12 (17%) for other indications. The false negative rate was 5%, sensitivity 67%, the false positive rate was 25%, and specificity was 95%. Higher risk flaps monitored with the doppler had a higher return to theatre rate, 21% compared with 4% (p<0.001) and flap failure rate, 7% compared with 1% (p=0.002). Salvage rates for free flaps were similar in both groups (62% compared with 60%, p=1.0). There is not enough evidence to suggest that the implantable doppler reduces the rate of failed flaps in routine low-risk cases, and its value in monitoring high-risk reconstructions require evaluation in a prospective randomised study.

The efficacy of the Cook-Swartz implantable Doppler in the detection of free-flap compromise: a systematic review protocol

IntroductionThe Cook-Swartz implantable Doppler monitors venous or arterial blood flow from free flaps and can detect free-flap compromise. Previous studies have shown that the use of this Doppler can improve...

A chimaeric-pattern flap design for implantable Doppler surrogate monitoring: A novel placement technique

Postoperative flap monitoring is a vital aspect of free tissue transfer in order to detect early vascular compromise and to enable early flap salvage. The implantable Doppler monitoring system is one of many monitoring devices used to ensure accuracy and reduce unnecessary flap explorations. However, there are a number of concerns with its use, namely tension on the anastomosis, possible vessel constriction and false-negative detection. This study aimed to alleviate these concerns, by introducing a new method of placing the implantable Doppler probe on the adjacent vessel limb of a chimaeric flap. This is illustrated by a case series of chimaeric free tissue flaps that allow this surrogate placement of the Doppler probe. The flap is raised in a chimaeric fashion, with a main perforator pedicle to the skin or muscle paddle for the main reconstructive purpose and a side branch from the main pedicle going to a smaller adipofascial or muscle flap for monitoring. This branch vascular pedicle leading to the chimaeric tissue is kept sufficiently long to enable placement of the Doppler cuff and prevent turbulence. The probe of a Cook-Swartz implantable Doppler system is placed around the branch pedicle, approximately 5 mm from the branching point, and secured with a vessel clip. This is then secured away from the major vessels of the main free flap. Removal of the probe's crystal and wire is easily done with a single gentle traction on postoperative day 7. Five cases of chimaeric free flaps were performed with this manoeuvre: three thoracodorsal perforator chimaeric flaps for head-and-neck or extremity reconstruction, one latissimus dorsi neuromuscular chimaeric flap for facial reanimation and one digastric lymph node transfer for the treatment of lower limb lymphoedema. The Doppler system showed a low but sustained oscillating flow in all cases indicating vascular patency, with minimal flow interference from other large-calibre vessels. There was no discernible kinking on the anastomosis. There were no complications encountered during probe removal. This postoperative monitoring manoeuvre was done successfully with good results. The monitoring equipment is very sensitive to any flow disturbance due to positional changes in the head-and-neck region or the extremities and is able to detect flow changes in buried flaps postoperatively. Chimaeric flap composition is easier now than before because of perforator-oriented pedicle dissection, and surrogate Doppler monitoring is one more application of the chimaeric flap. This novel chimaeric fashion of implantable Doppler probe placement is a good surrogate measure of flow in the main pedicle.

Postoperative monitoring of lower limb free flaps with the Cook-Swartz implantable Doppler probe: A clinical trial

Postoperative monitoring of lower limb free flaps with the Cook-Swartz implantable Doppler probe: A clinical trial

Sutured Attachment of the Implantable Doppler Probe Cuff for Large or Complex Pedicles in Free Tissue Transfer

The Cook-Swartz implantable Doppler probe (Cook Medical(®), Cook Ireland Ltd., Limerick, Ireland) has evolved as a useful option for postoperative free flap monitoring. For placement, the probe either is left unattached around the venous pedicle or is secured. In our experience with over 300 applications, we typically secure the cuff with two small microclips, or use fibrin glue. These techniques require redundant silicone cuff for apposition; however, we have encountered some vessels that are of sufficiently large diameter as to not provide enough cuff to employ these methods. The first technique comprises the application of two interrupted sutures through the cuff ends to mimic the technique of microclips. The sutures can be tightened to the desired tension and can be used in cases where the cuff ends are not in direct apposition. A second technique is to excise a segment of silicone cuff and either clip or suture the excised segment to the cuff ends, effectively elongating the cuff diameter. All four techniques (nonattachment, microclip fixation, suture fixation, silicone cuff elongation) have been used effectively, and none have resulted in any complications. Of note, the technique of nonattachment was associated with an increased rate of false-positive results, as migration away from the vessel was postulated to have occurred. There are a range of techniques for attachment of the implantable Doppler probe, and each contributes to the range of options for cuff attachment in difficult cases, with each technique worthwhile in particular settings.

Introduction of the Implantable Doppler System Did Not Lead to an Increased Salvage Rate of Compromised Flaps: A Multivariate Analysis

The Cook-Swartz implantable Doppler system was introduced at the Uppsala University Hospital to ease free flap monitoring and improve salvage rates by an earlier detection of vascular compromise. The aim of the current analysis was to investigate whether the system indeed improved the salvage rate of revisions. All cases that needed revision among a consecutive series of patients being monitored with the implantable Doppler system between June of 2006 and January of 2009 were compared with a similar set of patients operated on before the introduction of the implantable Doppler system over an equal time span monitored with conventional methods. Data were extracted from the medical files of the patients. Logistic regression was used to identify factors associated with the outcome of the revision. Values of p < 0.05 were considered statistically significant. A total of 327 flaps were monitored with the implantable Doppler system, of which 35 needed revision. In the control group, 303 flaps were included, of which 40 needed revision. The revision was successful in 69 percent of the cases in the implantable Doppler system group; in the group monitored by only conventional methods, this rate was 60 percent. Univariate analysis showed no statistical difference between these success rates (p = 0.441; odds ratio, 1.455; 95 percent confidence interval, 0.560 to 3.775). Multivariate analysis did not show a statistical difference either (p = 0.799; odds ratio, 1.143; 95 percent confidence interval, 0.410 to 3.182). The introduction of the implantable Doppler system did not lead to a significant increase in the salvage rate of revised flaps.

Buried Free Flaps for Breast Reconstruction: A New Technique Using the Cook-Swartz Implantable Doppler Probe for Postoperative Monitoring

Buried Free Flaps for Breast Reconstruction : A New Technique Using the Cook-Swartz Implantable Doppler Probe for Postoperative Monitoring

Postoperative Monitoring of Free Flaps in Autologous Breast Reconstruction: A Multicenter Comparison of 398 Flaps Using Clinical Monitoring, Microdialysis, and the Implantable Doppler Probe

Many techniques for flap monitoring following free tissue transfer have been described; however, there is little evidence that any of these techniques allow for greater rates of flap salvage over clinical monitoring alone. We sought to compare three established monitoring techniques across three experienced microsurgical centers in a comparable cohort of patients. A retrospective, matched cohort study of 398 consecutive free flaps in 347 patients undergoing autologous breast reconstruction was undertaken across three institutions during the same 3-year period, with a single form of postoperative monitoring used at each institution: clinical monitoring alone, the Cook-Swartz implantable Doppler probe, or microdialysis. Both objective and subjective measures of efficacy were assessed. Clinical monitoring alone, the implantable Doppler probe, and microdialysis showed statistically similar rates of flap salvage. False-negative rates were also statistically similar (only seen in the clinically monitored group). However, there was a statistically significant increase in false-positive alarms causing needless take-backs to theater in the microdialysis and implantable Doppler arms, P < 0.001. This study did not find any technique superior to clinical monitoring alone. New monitoring technologies should be compared objectively with clinical monitoring as the current standard in postoperative flap monitoring.

Postoperative monitoring of lower limb free flaps with the Cook–Swartz implantable Doppler probe: A clinical trial

Free flaps to the lower limb have inherently high venous pressures, potentially impairing flap viability, which may lead to limb amputation if flap failure ensues. Adequate monitoring of flap perfusion is thus essential, with timely detection of flap compromise able to potentiate flap salvage. While clinical monitoring has been popularized, recent use of the implantable Doppler probe has been used with success in other free flap settings. A comparative study of 40 consecutive patients undergoing microvascular free flap reconstruction of lower limb defects was undertaken, with postoperative monitoring achieved with either clinical monitoring alone or the use of the Cook-Swartz implantable Doppler probe. The use of the implantable Doppler probe was associated with salvage of 2/2 compromised flaps compared to salvage of 2/5 compromised flaps in the group undergoing clinical monitoring alone (salvage rate 100% vs. 40%, P = 0.28). While not statistically significant, this was a strong trend toward an improved flap salvage rate with the use of the implantable Doppler probe. There were no false positives or negatives in either group. One flap loss in the clinically monitored group resulted in limb amputation (the only amputation in the cohort). A trend toward early detection and salvage of flaps with anastomotic insufficiency was seen with the use of the Cook-Swartz implantable Doppler probe. These findings suggest a possible benefit of this technique as a stand-alone or adjunctive tool in the clinical monitoring of free flaps, with further investigation warranted into the broader application of these devices.

The efficacy of postoperative monitoring: A single surgeon comparison of clinical monitoring and the implantable Doppler probe in 547 consecutive free flaps

An important element in achieving high success rates with free flap surgery has been the use of different techniques for monitoring flaps postoperatively as a means to detecting vascular compromise. Successful monitoring of the vascular pedicle to a flap can potentiate rapid return to theater in the setting of compromise, with the potential to salvage the flap. There is little evidence that any technique offers any advantage over clinical monitoring alone. A consecutive series of 547 patients from a single plastic surgical unit who underwent a fasciocutaneous free flap operation for breast reconstruction [deep inferior epigastric artery perforator (DIEP) flap, superficial inferior epigastric artery (SIEA) flap, or superior gluteal artery perforator (SGAP) flap] were included. A comparison was made between the first 426 consecutive patients in whom flap monitoring was performed using clinical monitoring alone and the subsequent 121 patients in whom monitoring was achieved with the Cook-Swartz implantable Doppler probe. Outcome measures included flap salvage rate and false-positive rate. There was a strong trend toward improved salvage rates with the implantable Doppler probe compared with clinical monitoring (80% vs. 66%, P = 0.48). When combined with the literature (meta-analysis), the data prove statistically significant (P < 0.01). There was no statistical difference between the groups for false-positive rates. Flap monitoring with the implantable Doppler probe can improve flap salvage rates without increasing the rate of false-positive takebacks.

The implantable Cook Doppler probe for postoperative monitoring in head and neck free flap reconstruction: a critical evaluation

Introduction: Microvascular reconstruction requires postoperative monitoring to prevent vascular occlusion and flap failure. For some head and neck reconstructions, clinical monitoring is difficult and in others impossible due to flap components or site. The Cook–Swartz implantable Doppler flow system provides continual feedback on vascular pedicle status. This provides rapid assessment of minute-to-minute changes in microvascular flow that may allow intervention before total vascular occlusion permitting expeditious re-exploration for threatened flap failure, improving flap salvage.

PR24 POST OPERATIVE MONITORING IN 23 MICROVASCULAR FREE‐FLAP OPERATIONS UTILISING THE IMPLANTABLE DOPPLER FLOW SYSTEM

Purpose: The Cook‐Swartz Implantable Doppler has been used to provide continuous feedback on the vascular status of free flaps and has been reported to improve flap salvage. We review our experience of this device, its efficacy and suitability for ongoing use in free flap monitoring.Methodology: All patients who were monitored following free flap reconstruction using the Cook Swartz Implantable Doppler in two Hospitals in Christchurch, NZ were retrospectively reviewed from its first use in December 2006 to December 2008.Results: In total 43 probes were used on 23 flaps (4 buried, 7 intraoral) in 21 patients (range 17–83 yrs). The probes were placed on the artery in all cases and the vein in 21 cases. 21 (91.3%) flaps survived. 20 flaps had reliable Doppler signals. Overall there were 2 flap failures (8.7%) and these were not salvageable. There were no technical difficulties with application or removal of the probes and it was well received by junior medical/nursing staff. It provided peace of mind to surgeons performing free flap surgery outside the base hospital (6 cases).Conclusion: The implantable Doppler probe is a useful tool in monitoring free flaps where clinical evaluation is difficult especially when flaps are buried. Our current experience supports its ongoing use as a free flap monitoring tool at our institution.

Performing two DIEP flaps in a working day: an achievable and reproducible practice

While the deep inferior epigastric artery perforator (DIEP) flap is a reliable technique for autologous breast reconstruction, the meticulous dissection of perforators may require lengthy operative times. In our unit, we have performed 600 free flaps for breast reconstruction over 8 years and have reduced operative times with a combination of preoperative computed tomographic angiography (CTA), various anastomotic techniques and the Cook-Swartz implantable Doppler probe for perfusion monitoring. We sought to assess the feasibility of performing two DIEP flaps within the working hours of a single day. A review of 101 consecutive patients undergoing DIEP flap breast reconstruction in a 12-month period was performed, comparing one DIEP flap per day (n=43) to two DIEP flaps per day (n=58). Complications, outcomes and techniques used were critically analysed. For cases of two DIEP flaps per day, a comparison was made between the use of two separate operating theatres (n=44) and a single consecutive theatre (n=14). Complications did not increase when two DIEP flaps were performed in a single working day. The use of vascular closure staple (VCS) sutures and ring couplers resulted in statistically significant reductions in anastomotic times. The use of two separate theatres for performing two DIEP flaps resulted in a reduction of 59min in operative time per case (p=0.004). Two DIEP flaps can be safely and routinely performed within the hours of a single working day. By minimising operative times, these techniques can improve productivity and substantially decrease surgeon fatigue.

Implantable Doppler flow system: Experience with 24 microvascular free-flap operations

Microvascular reconstruction requires postoperative monitoring to prevent vascular occlusion and flap failure. These methods require skilled personnel and can delay diagnosis and treatment of threatened flap failures. The Cook-Swartz implantable Doppler flow system provides continual feedback on vascular pedicle status, which in turn provides rapid assessment of minute-to-minute changes in flap vasculature that may allow intervention before total vascular occlusion and expeditious reexploration for threatened flap failure, possibly improving flap salvage. Charts of 24 patients with microvascular free-flap reconstruction and implantation of Doppler flow system at Mayo Clinic Rochester were retrospectively reviewed. Surgical technique and flap outcomes were evaluated. Microvascular reconstruction and implantation of Doppler flow system were successful in all patients. Complications were minimal, and postoperative monitoring system facilitated rapid reexploration when necessary. Flap viability was 96%. Doppler flow system is reliable for monitoring minute-to-minute changes in microvascular flap vascular status postoperatively, and allows rapid recognition of complications and facilitating reexploration. This is a valuable, easily mastered tool for microvascular reconstructive surgery. May alter postoperative monitoring techniques of microvascular surgeons.