Perioperative Hyperspectral Imaging to Assess Mastectomy Skin Flap and DIEP Flap Perfusion in Immediate Autologous Breast Reconstruction: A Pilot Study

Mastectomy skin flap necrosis (MSFN) and partial DIEP (deep inferior epigastric artery perforator) flap loss represent two frequently reported complications in immediate autologous breast reconstruction. These complications could be prevented when areas of insufficient tissue perfusion are detected intraoperatively. Hyperspectral imaging (HSI) is a relatively novel, non-invasive imaging technique, which could be used to objectively assess tissue perfusion through analysis of tissue oxygenation patterns (StO2%), near-infrared (NIR%), tissue hemoglobin (THI%), and tissue water (TWI%) perfusion indices. This prospective clinical pilot study aimed to evaluate the efficacy of HSI for tissue perfusion assessment and to identify a cut-off value for flap necrosis. Ten patients with a mean age of 55.4 years underwent immediate unilateral autologous breast reconstruction. Prior, during and up to 72 h after surgery, a total of 19 hyperspectral images per patient were acquired. MSFN was observed in 3 out of 10 patients. No DIEP flap necrosis was observed. In all MSFN cases, an increased THI% and decreased StO2%, NIR%, and TWI% were observed when compared to the vital group. StO2% was found to be the most sensitive parameter to detect MSFN with a statistically significant lower mean StO2% (51% in the vital group versus 32% in the necrosis group, p < 0.0001) and a cut-off value of 36.29% for flap necrosis. HSI has the potential to accurately assess mastectomy skin flap perfusion and discriminate between vital and necrotic skin flap during the early postoperative period prior to clinical observation. Although the results should be confirmed in future studies, including DIEP flap necrosis specifically, these findings suggest that HSI can aid clinicians in postoperative mastectomy skin flap and DIEP flap monitoring.

Primary thrombolysis for free flap surgery in head and neck reconstruction: a case report and review

The use of free flaps is an essential and reliable method of reconstruction in complex head and neck defects. Flap failure remains the most feared complication, the most common cause being pedicle thrombosis. Among other measures, thrombolysis is useful when manual thrombectomy has failed to restore flap perfusion, in the setting of late or established thrombosis, or in arterial thrombosis with distal clot propagation. We report a case of pedicle arterial thrombosis with distal clot propagation which occurred during reconstruction of a maxillectomy defect, and was successfully treated with thrombolysis using recombinant tissue plasminogen activator. We also review the literature regarding the use of thrombolysis in free flap surgery, and propose an algorithm for the salvage of free flaps in head and neck reconstruction.

1362 Early Experience on Flap Perfusion? Monitoring with Near-Infrared Spectroscopy Tissue Oximetry

Introduction Free flap reconstruction is a routine procedure with more than 99% success rates. Yet, vascular complications may occur leading to flap failure. Thus, early detection of vascular compromise is crucial for flap salvage. Vascular complications may be detected early using Infrared Spectroscopy Tissue Oximetry (NIRS) parameter changes. This method can distinguish changes caused by arterial and venous thrombosis before surgical re-exploration. This study aims to assess the validity or feasibility of using NIRS Oximetry in free flap monitoring and compare it to standard clinical examination and Doppler . Method A prospective cohort observational study. Flap perfusion was measured using the INVOS™ 7100 system for 24-h continuous postoperative monitoring. The data were compared to findings of clinical assessment. Results Ten patients completed the measurements after breast flap reconstruction. Age ranged from 41 to 61 years. Patients underwent immediate d eep inferior epigastric perforators (DIEP) (n = 4), delayed DIEP (n = 4), transverse upper gracilis flap (n = 1), and latissimus dorsi flap with lipofilling (n = 1). All ten flaps are successfully monitored for 24hrs post-operatively. The overall flap survival was 100%. Clinical examination, Doppler studies and surgical outcome were consistent with NIRS (need numbers). There were no false negatives. Conclusions NIRS tissue oximetry could potentially monitor flaps non-invasively. Future adequately sampled cohort study is recommended.

Intraoperative Indocyanine Green Angiography for Assessing Flap Perfusion in Skull Base Reconstruction: A Systematic Review

Objective This study was aimed to study the current use of intraoperative indocyanine green (ICG) angiography during skull base reconstruction and understand its efficacy in predicting postoperative magnetic resonance imaging (MRI) enhancement and flap. Study Design The Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and Google Scholar databases were searched from the date of inception until August 2020 for studies of ICG flap perfusion assessment during skull base reconstruction. The primary outcome of interest was the development of cerebrospinal fluid (CSF) leak after skull base reconstruction. Secondary outcomes of interest included postoperative meningitis, flap MRI enhancement, flap necrosis, flap perfusion measurements, and total complications. Results Search results yielded 189 studies, from which seven studies with a total of 104 patients were included in the final analysis. There were 44 nasoseptal flaps (NSF), two lateral nasal wall flaps (LNWF), 14 pericranial flaps (PCF), and 44 microvascular free flaps. The rates of CSF leak and postoperative MRI enhancement were 11 and 94%, respectively. There was one case of postoperative meningitis. Pooled analysis of the available data showed that intraoperative ICG flap perfusion was associated with flap enhancement on postoperative MRI (p = 0.008) and CSF leak (p = 0.315) by Fisher's exact test. Conclusion The available literature suggests intraoperative ICG enhancement is associated with postoperative MRI enhancement. Given the small sample sizes in the literature and the rarity of complications associated with skull base reconstruction, intraoperative ICG enhancement has not been predictive of flap necrosis or postoperative complications such as CSF leak or meningitis. Level of Evidence This study presents level 3 evidence as a systematic review of case studies, case reports, and retrospective and prospective trials with no blinding, controls, and inconsistently applied reference standards.

Two-point flap blood glucose measurement for monitoring propeller flap perfusion – a case report

Monitoring flap perfusion is a helpful method of postoperative care allowing for proper early intervention in and salvage of a flap. The basic means of blood supply monitoring include the assessment of color, warmth, skin tension, and a pin-prick examination. Along with advances in microvascular surgery, methods of flap blood circulation assessment have been also developed. This paper presents the case of a peroneal artery propeller perforator flap for the treatment of a secondary wound resulting from an orthopedic complication of ankle arthrodesis. Blood glucose level (BGL) was used to monitor flap perfusion as an early indicator of possible venous congestion. It is well known that in case of vascular compromise, whether arterial or venous, the flap salvage rate depends on how fast the vascular problem is resolved. Arterial insufficiency is easily detectable, and the arterial flow may be also monitored with minidoppler, however venous insufficiency causes symptoms less dynamically. This fact emphasized the importance of early prediction of venous insufficiency before clinical symptoms appear. It is crucial that the time between pedicle impairment and clinical signs is as short as possible.