Evidence to Support Controversy in Microsurgery:

Risk factors of transient and permanent hypoparathyroidism after thyroidectomy: a systematic review and meta-analysis

BACKGROUND

Postoperative hypoparathyroidism (hypoPT) is a common complication following thyroid surgery. However, current research findings on the risk factors for post-thyroid surgery hypoPT are not entirely consistent, and the same risk factors may have different impacts on transient and permanent hypoPT. Therefore, there is a need for a comprehensive study to summarize and explore the risk factors for both transient and permanent hypoPT after thyroid surgery.

MATERIALS AND METHODS

Two databases (PubMed and Embase) were searched from inception to 2024. The Newcastle-Ottawa Scale was used to rate study quality. Pooled odds ratios were used to calculate the relationship of each risk factor with transient and permanent hypoPT. Subgroup analyses were conducted for hypoPT with different definition-time (6 or 12 months). Publication bias was assessed using Begg's test and Egger's test.

RESULTS

A total of 19 risk factors from the 93 studies were included in the analysis. Among them, sex and parathyroid autotransplantation were the most frequently reported risk factors. Meta-analysis demonstrated that sex (female vs. male), cN stage, central neck dissection, lateral neck dissection, extent of central neck dissection (bilateral vs. unilateral), surgery [total thyroidectomy (TT) vs. lobectomy], surgery type (TT vs. sub-TT), incidental parathyroidectomy, and pathology (cancer vs. benign) were significantly associated with transient and permanent hypoPT. Preoperative calcium and parathyroid autotransplantation were only identified as risk factors for transient hypoPT, while preoperative PTH was a protective factor. Additionally, node metastasis and parathyroid in specimen were associated with permanent hypoPT.

CONCLUSION

The highest risk of hypoPT occurs in female thyroid cancer patients with lymph node metastasis undergoing TT combined with neck dissection. The key to preventing postoperative hypoPT lies in the selection of surgical approach and intraoperative protection.

How to Start and Build Microsurgery Practice-Topics on Success and Sustainability: Global/International

Many young microsurgeons begin their careers at established hospitals where microsurgery resources are limited. This article shares the authors' experiences in overcoming challenges and establishing a microsurgery practice in a new hospital. Due to the lack of equipment, limited support from colleagues, absence of discussion partners, fear of failure, and unpredictable situations, many aspiring microsurgeons lose their motivation. The purpose of this article is to guide future microsurgeons by describing the author's actions and suggesting improvements for their first free flap case. Key factors for building a successful, sustainable, and enjoyable microsurgery practice include remembering your training and mentors, acquiring fundamental knowledge of microsurgery, creating a supportive ecosystem, and having fun.

Thromboelastography in Microsurgical Reconstruction: A Systematic Review

The aim of this review was to identify studies that used thromboelastography (TEG) or rotational thromboelastometry (ROTEM) in microsurgical free flap reconstruction and analyse whether it is a useful adjunct at predicting and identifying thrombotic complications. A search was conducted using the MEDLINE database using the keywords "thromboelastogram", "TEG", "thromboelastography", "free flaps" and "free tissue transfer" using a two-component search with the Boolean operators "OR" and "AND". Eight studies were retrieved using the search criteria. Seven studies met the inclusion criteria, and a further study was found citing several articles from the initial search. Combined, there were 528 patients who underwent 600 free flaps. A total of 10.3% (62) arterial and venous thromboses were reported in the studies, and the combined flap failure rate was 5.2% (26). A total of 67% (4/6) of the studies supported the use of TEG as a predictive tool to detect thromboses, including three retrospective case series and one prospective cohort, which were all statistically significant. There is low-quality evidence (level IV) that a pre-operative TEG and functional fibrinogen to platelet ratio of ≥42 can identify patients at risk of adverse post-operative thrombotic events following free flap surgery; however, further validation is required. Higher quality, standardised prospective or randomised control trials are required to further evaluate the predictive value of TEG. As a pre-operative screening tool, TEG can help to detect pathological changes in coagulation, aid in the transfusion of blood products, target anticoagulation therapy and predict possible adverse events aiding to further reduce patient morbidity.

Retrograde Manual Lymphatic Drainage following Vascularized Lymph Node Transfer to Distal Recipient Sites for Extremity Lymphedema: A Retrospective Study and Literature Review

BACKGROUND

Vascularized lymph node transfer is an efficacious treatment for extremity lymphedema. This study investigated the outcome of retrograde manual lymphatic drainage for vascularized lymph node transfer to distal recipient sites.

METHODS

Lymphedema patients who underwent either complete decongestive therapy or vascularized lymph node transfer between 2013 and 2018 were retrospectively included. Retrograde manual lymphatic drainage was started with intermittent manual compression and the assistance of a sphygmomanometer and proximal-to-distal massage of the limb 1 month postoperatively. Outcomes evaluations used the circumferential reduction rate and the Lymphedema-Specific Quality-of-Life Questionnaire. Outcomes of vascularized lymph node transfer to proximal versus distal recipient sites in the literature between 2006 and 2018 were also compared.

RESULTS

One hundred thirty-eight unilateral extremity lymphedema patients, including 68 patients in the complete decongestive therapy group and 70 patients in the vascularized lymph node transfer group, were included. The mean circumferential reduction rate of 38.9 ± 2.5 percent in the vascularized lymph node transfer group was statistically greater than the 13.2 ± 10.1 percent rate in the complete decongestive therapy group (p = 0.01). At a mean follow-up of 36 months, the improvement of overall Lymphedema-Specific Quality-of-Life Questionnaire score from 3.8 ± 0.3 to 7.5 ± 1.8 in the vascularized lymph node transfer group was statistically greater than that in the complete decongestive therapy group (from 4.7 ± 0.9 to 5.0 ± 1.9; p < 0.01). In total, 536 lymphedema patients who underwent 548 vascularized lymph node transfers in 23 published articles were reviewed; the distal recipient-site group was found to have more efficacious results than the proximal recipient-site group.

CONCLUSION

Vascularized lymph node transfer to a distal recipient site with standard retrograde manual lymphatic drainage significantly improved circumferential reduction rates and Lymphedema-Specific Quality-of-Life Questionnaire scores.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Amputation versus Free Flap: Long-Term Outcomes of Microsurgical Limb Salvage and Risk Factors for Amputation in the Diabetic Population

BACKGROUND

Reconstructive microsurgery is an effective limb-saving option for nonhealing lower extremity wounds in diabetic patients. However, the ability to predict the future need for amputation is unclear. This article seeks to identify risk factors for amputation following microsurgical free tissue transfer in the diabetic lower extremity.

METHODS

Diabetic patients undergoing lower extremity free flap surgery between August of 2011 and January of 2018 performed by a single surgeon were identified retrospectively. Patient comorbidities, reconstructive conditions and flap traits, microsurgical outcomes, and long-term outcomes were examined. Variables conferring risk for future amputation were examined by means of regression analysis.

RESULTS

Sixty-four patients met the criteria. The overall immediate flap success rate was 94 percent (60 of 64). Long term, 50 patients (78.1 percent) underwent successful salvage, and 14 patients (21.9 percent) required major amputation. Acute flap loss resulted in four amputations, and delayed complications (hematoma, infection, recurrent nonhealing) resulted in 10 amputations. The average time to amputation was 5.6 months. Risk factors for amputation were end-stage renal disease (OR, 30.7; p = 0.0087), hindfoot wounds (OR, 4.6; p = 0.020), elevated hemoglobin A1C level greater than 8.4 percent (OR, 1.4; p = 0.05), and positive wound cultures (OR, 6.1; p = 0.003).

CONCLUSIONS

Multiple comorbidities and poor glucose control were identified as risk factors for amputation after free flap limb salvage. However, successful limb preservation is possible.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

The Second Free Tissue Transfer After the First Free Flap Loss for a Complex Scalp Reconstruction: Our Strategy to Success With a Staged Approach

ABSTRACT

Scalp reconstruction for a critical neurosurgical patient, as lifesaving efforts continued, can be challenging and a free tissue transfer is often needed to achieve reliable soft tissue coverage. However, the patient's labile perioperative condition may compromise successful reconstruction and perioperative hypotension is one of the major known factors for the failure of free tissue transfer. In this report, the authors encountered such an instance, and present our strategy in overcoming this hurdle toward obtaining successful scalp reconstruction with second free tissue transfer after the first free flap loss. After optimizing the patient's medical condition, the second free tissue transfer was performed in 2 stages with recipient vessel dissection during the first stage and the flap harvest and microvascular anastomoses during the second stage. Our staged approach is warranted to ensure the patient can tolerate the stressor of general anesthesia and to precondition the patient for ultimate successful second free tissue transfer.

Evaluation of the American Society of Anesthesiologists Physical Status Classification System in Risk Assessment for Lower Extremity Reconstruction with Free Tissue Transfer

BACKGROUND

 The applicability of free flap reconstruction for lower extremity (LE) defects in high-risk patients continues to require ongoing review. The aim of this study was to analyze the risk factors, management, and outcome of LE free flap reconstruction in high-risk (American Society of Anesthesiologists [ASA] class 3 or 4) patients.

METHODS

 A retrospective chart review was performed for all patients who underwent LE reconstruction in our Institution (Level I Trauma Center) from 2013 to 2019. Medical records and the authors' prospectively maintained database were analyzed with respect to ASA class, comorbidities, and postoperative complications. All patients were treated using the same pre-, intra-, and postoperative multidisciplinary approach.

RESULTS

 A total of 199 patients were analyzed. Sixty-six flaps were transferred in 60 patients with an ASA class 3 or higher. High-risk patients did not present a higher rate of flap loss or LE amputation. The overall flap success rate was 92%. There were five flap losses in high-risk patients. Three of these five patients underwent a successful second free flap reconstruction. The overall success rate of LE reconstruction in high-risk patients was 90%. Four patients with successful free flap ended up in LE amputation due to bone infection and two patients underwent an amputation after the first free flap failure.

CONCLUSION

 Free flap reconstruction for LE defects in high-risk patients is a safe and reliable procedure for selected patients when an experienced multidisciplinary team is involved. Bone infection was the only variable associated with LE amputation.

The "Double hit": Free tissue transfer is optimal in comorbid population with irradiated wounds for successful limb salvage

BACKGROUND

Radiation therapy causes histopathologic changes in tissues, including fibrosis, loss of tissue planes, and vascular damage, which can lead to chronic wound formation. Patients with nonhealing, irradiated wounds and comorbidities that affect microvasculature suffer a "double hit", which leads to delayed wound healing. Local wound care and grafts are commonly insufficient. In this study, we evaluated limb salvage outcomes and long-term complications after free tissue transfer (FTT) in patients with chronic, irradiated leg wounds.

METHODS

We retrospectively reviewed patients with irradiated lower extremity wounds who underwent FTT from 2012 to 2017. Primary outcomes included limb salvage, ambulation, and overall flap success. Reconstruction involved complete excision of irradiated tissue and coverage with well-vascularized tissue.

RESULTS

Seven free flaps in six patients were identified. Average age was 68.4 years and average BMI was 27.8 kg/m². Comorbid conditions included hypertension (57.1%), peripheral vascular disease (57.1%), underlying hypercoagulability (42.9%), diabetes (14.3%), and tobacco use (14.3%). Wounds were present for an average of 25.5 months prior to FTT. Donor sites included anterolateral thigh (71.4%), vastus lateralis (14.3%), and latissimus dorsi (14.3%). Overall flap success rate was 100% with one patient requiring reoperation for dehiscence. Limb salvage rate was 85.7% with one patient undergoing elective amputation due to pain. All patients could ambulate (one used a prosthesis) at a mean follow-up time of 1.4 years.

CONCLUSIONS

Radiation therapy in a comorbid population often leads to the formation of chronic nonhealing wounds. We advocate for earlier consideration of FTT to provide healthy vascularized tissues, thereby avoiding prolonged wound care and patient burden. Successful limb salvage outcomes can be achieved.

Limb Salvage Rates and Functional Outcomes Using a Longitudinal Slit Arteriotomy End-to-Side Anastomosis for Limb-Threatening Defects in a High-Risk Patient Population

BACKGROUND

Limb salvage techniques using free tissue transfer in patients with chronic wounds caused by longstanding osteomyelitis, diabetes, and peripheral vascular disease are technically challenging. The longitudinal slit arteriotomy end-to-side anastomosis is the authors' preferred technique because it is the least invasive arteriotomy and is especially important for diseased recipient arteries. The authors reviewed highly comorbid patients who underwent free tissue transfer with this technique to understand the success rates, overall outcomes, and long-term limb salvage rates.

METHODS

A retrospective review was performed to analyze outcomes of free tissue transfer using longitudinal slit arteriotomy end-to-side anastomosis between 2012 and 2018 performed by the senior surgeon (K.K.E.).

RESULTS

One hundred fifteen free flaps were identified. Patients were, on average, 55.9 years old, with a body mass index of 29.2 kg/m. Comorbidities included osteomyelitis (83.5 percent), hypertension (60.9 percent), tobacco use (46.1 percent), diabetes (44.3 percent), peripheral vascular disease (44.3 percent), hypercoagulability (35.7 percent), and arterial calcifications (17.4 percent). Overall flap success was 93.0 percent; 27.8 percent required reoperation perioperatively because of complications. On univariate analysis, diabetes mellitus, hypertension, and hypercoagulability were significantly associated with eventual amputation (p < 0.05). Multivariate analysis showed that intraoperative thrombosis and take back was independently associated with flap failure. There was an overall limb salvage rate of 83.5 percent, and of those salvaged, 92.7 percent were ambulating without a prosthesis at a mean follow-up of 1.53 years.

CONCLUSIONS

This is the largest series of longitudinal slit arteriotomy end-to-side anastomosis for patients undergoing free tissue transfer for limb-threatening defects in the compromised host. Overall flap success, limb salvage rates, and functional outcomes are high using this technique.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Vagal Stimulation as Result of Pleural Stretch Secondary to Retraction during Internal Mammary Anastomosis

Supplemental Digital Content is available in the text.

Thromboprophylaxis in Head and Neck Microvascular Reconstruction

Head and neck patients undergoing microvascular reconstruction are at high risk for thromboembolism. While the prevention of thromboembolism has become an essential aspect of care, within the field of microsurgery, concern for anastomotic complications have hindered the creation of an accepted regimen. The aim of this review was to evaluate the risks and benefits of prophylactic agents for thromboprophylaxis. A literature search was conducted in MEDLINE, Cochrane Library, and PubMed/NCBI databases. Articles discussing thromboprophylaxis in otolaryngology, head and neck surgery, or microvascular reconstruction were considered in the review from the past 30 years. The majority of patients undergoing microvascular surgery have multiple risk factors for thrombus formation. Several consensus guidelines exist for the prophylaxis in patients who are critically ill, undergoing surgery, or with malignancy. Significant evidence supports the routine use of mechanical means, such as early mobilization and pneumatic compression along with subcutaneous heparin. Low-molecular-weight heparin is also frequently utilized, although results are largely divided. Data on aspirin remain equivocal. Studies on microvascular failure and flap loss have demonstrated little to no association with chemoprophylaxis. The evidence for postoperative thromboprophylaxis regimens in patients undergoing head and neck free tissue transfer is variable. Multiple studies have supported the use of unfractionated heparin or low-molecular-weight heparin. There appears to be an expert consensus for the combined use of mechanical prophylactic methods and chemical prophylaxis. Prospective randomized trials are required to validate the most effective combination of chemoprophylaxis agents.

Smoking and Flap Survival

Purpose

The aim of this study was to compare the complications of flap surgery in non-smokers and smokers and to determine how the incidence of complications was affected by the abstinence period from smoking before and after flap surgery.

Methods

In PubMed and Scopus, terms "smoking" and "flap survival" were used, which resulted in 113 papers and 65 papers, respectively. After excluding 6 duplicate titles, 172 titles were reviewed. Among them, 45 abstracts were excluded, 20 full papers were reviewed, and finally 15 papers were analyzed.

Results

Post-operative complications such as flap necrosis (P < .001), hematoma (P < .001), and fat necrosis (P = .003) occurred significantly more frequently in smokers than in non-smokers. The flap loss rate was significantly higher in smokers who were abstinent for 24 hours post-operatively than in non-smokers (n = 1464, odds ratio [OR] = 4.885, 95% confidence interval [CI] = 2.071-11.524, P < .001). The flap loss rate was significantly lower in smokers who were abstinent for 1 week post-operatively than in those who were abstinent for 24 hours post-operatively (n = 131, OR = 0.252, 95% CI = 0.074-0.851, P = .027). No significant difference in flap loss was found between non-smokers and smokers who were abstinent for 1 week preoperatively (n = 1519, OR = 1.229, 95% CI = 0.482-3.134, P = .666) or for 4 weeks preoperatively (n = 1576, OR = 1.902, 95% CI = 0.383-2.119, P = .812).

Conclusion

Since smoking decreases the alveolar oxygen pressure and subcutaneous wound tissue oxygen, and nicotine causes vasoconstriction, smokers are more likely to experience flap loss, hematoma, or fat necrosis than non-smokers. Preoperative and post-operative abstinence period of at least 1 week is necessary for smokers who undergo flap operations.

Resident Involvement in Microsurgery: An American College of Surgeons National Surgical Quality Improvement Program Analysis

OBJECTIVE

In the current healthcare climate, there is increased focus on medical errors, patient outcomes, and the influence of resident participation on these metrics. Other studies have examined the influence of resident involvement on surgical outcomes, but the arena of microsurgery, with added complexity and learning curve, has yet to be investigated.

DESIGN

A retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program database was performed to find patients undergoing procedures with free tissue transfer by screening for Current Procedural Terminology codes. Primary outcomes measured include flap failure, wound, infectious, and major and minor complications.

SETTING

This study was conducted at the Methodist Hospital, an academic hospital located in Houston, Texas.

PARTICIPANTS

Patients in the National Surgical Quality Improvement Program database between the years 2005 and 2012 undergoing microsurgical procedures were included in this analysis.

RESULTS

A total of 1466 patients met inclusion criteria. There was a statistically significant association of major complications with age, peripheral vascular disease, American Society of Anesthesiologists (ASA) classification of 3 or greater, total operative time, and year of operation. Multivariate analysis on minor complications demonstrated significant association with ASA class of 3 or 4. Resident involvement was not a significant factor among any outcome measures including major complications, minor complications, flap failure, wound complications, infectious complications, bleeding requiring transfusion, and unexpected reoperation rates within 30 days.

CONCLUSIONS

This study provides further evidence in support of the claim that resident involvement in microsurgery is safe and effective, with similar rates of major complications, minor complications, flap failure, and unexpected reoperation. High ASA classification and history of peripheral vascular disease were strong predictors of major complications and should be optimized preoperatively before free tissue transfer. Later years were associated with decreased major complication rates, which may be reflective of enhanced supervision standards.