Perforator Dissection Porcine Abdominal Model: A Novel Simulator to Improve Microsurgical Training

BACKGROUND

 Perforator dissection and flap elevation are routinely performed for microsurgical reconstruction; however, there is a steep learning curve to mastering these technical skills. Though live porcine models have been utilized as microsurgical training models, significant drawbacks limit their use. We recently developed a latex-perfused, nonliving, porcine abdomen perforator dissection simulation and described its anatomic similarity to the human deep inferior epigastric artery flap. The purpose was to assess the change in resident confidence in performing key operative steps of flap elevation and perforator dissection and obtain feedback on model realism and utility.

METHODS

 Seventeen plastic and reconstructive surgery resident physicians (postgraduate years 1-6) at a single institution participated in a perforator dissection session utilizing the simulation model. Each resident completed pre- and postactivity surveys to assess interval change in confidence in operating. The postactivity survey also asked residents to answer questions regarding their perception of the model's anatomic and surgical realism and utility in microsurgical training.

RESULTS

 Following a practice session using the latex-perfused, nonliving porcine abdomen, resident confidence was significantly increased in performing all key operative steps and the procedure overall (p = 0.001). All residents (n = 17, 100%) believed the model would improve "trainees' ability to perform perforator dissection in the operating room." Perforator, fascial, and pedicle anatomy were reported to be "Very" similar to human anatomy, with a median Likert score (MLS) of 4. Additionally, six out of the eight surgical steps were noted to be "Very" realistic, with only "Flap Design" and "Fascial Closure" found to be "Moderately" realistic with an MLS of 3.

CONCLUSION

 The latex-infused porcine abdominal model is a novel, realistic simulation for microsurgical trainee perforator dissection practice. This model offers a suitable substitute for perforator dissection practice, as its implementation within a microsurgery training course improves resident comfort and confidence.

Latex-Infused Porcine Abdominal Model: A Novel Microsurgery Simulator for Deep Inferior Epigastric Perforator Dissection

BACKGROUND

 Perforator dissection and flap elevation are routinely performed for microsurgical reconstruction; however, there is a steep learning curve to mastering these technical skills. Though live porcine models have been utilized as a microsurgical training model, there are significant drawbacks that limit their use, including cost, limited ability for repetition, and obstacles associated with animal care. Here we describe the creation of a novel perforator dissection model using latex augmented non-living porcine abdominal walls. We provide anatomic measurements that demonstrate valuable similarities and differences to human anatomy to maximize microsurgical trainee practice.

METHODS

 Six latex-infused porcine abdomens were dissected based on the deep cranial epigastric artery (DCEA). Dissection was centered over the abdominal wall mid-segment between the second and fourth nipple line. Dissection steps included exposure of lateral and medial row perforators, incision of anterior rectus sheath with perforator dissection, and dissection of DCEA pedicle. DCEA pedicle and perforator measurements were compared with deep inferior epigastric artery (DIEA) data in the literature.

RESULTS

 An average of seven perforators were consistently identified within each flap. Assembly of the model was performed quickly and allowed for two training sessions per specimen. Porcine abdominal walls demonstrate similar DCEA pedicle (2.6 ± 0.21 mm) and perforator (1.0 ± 0.18 mm) size compared with a human's DIEA (2.7 ± 0.27 mm, 1.1 ± 0.85 mm).

CONCLUSION

 The latex-infused porcine abdominal model is a novel, realistic simulation for perforator dissection practice for microsurgical trainees. Impact on resident comfort and confidence within a microsurgical training course is forthcoming.

"Please, Mr. Postman:" Exploring the Use of Letter Writing to Address Loneliness

PURPOSE

Informed by prior research and influenced by concerns that the COVID-19 pandemic heightened social isolation, this project examined the impact of a 12-month long letter writing project on levels of loneliness.

METHOD

Through partnerships with local anti-poverty agencies, pen pals were paired between MSW students and community members who utilize services at these organizations. Participants completed the UCLA Loneliness Scale before and after the intervention.

RESULTS

We found a mean decrease in loneliness at the end of the intervention.

DISCUSSION

Letter writing was a successful way to attend to loneliness due to its accessibility to the participants. Our letter writing intervention is different in many ways from e-mail and texting. Participants noted that the waiting process between letter gave them time to think more deeply about their response as well as event to look forward to (e.g. getting mail). We found that the low-tech aspects of the project might have been helpful to some participants.

CONCLUSION

Letter writing is an easily replicable, low-cost, low-tech activity for use by practitioners, which may be useful in a variety of social work settings to reduce loneliness.

Methodology of a multispecialty outpatient Obesity Treatment Research Program

Despite the large number of U.S. adults who overweight or obese, few providers have ready access to comprehensive lifestyle interventions, the cornerstone of medical obesity management. Our goal was to establish a research infrastructure embedded in a comprehensive lifestyle intervention treatment for obesity. The Obesity Treatment Research Program (OTRP) is a multi-specialty project at Mayo Clinic in Rochester, Minnesota designed to provide a high intensity, year-long, comprehensive lifestyle obesity treatment. The program includes a nutritional intervention designed to reduce energy intake, a physical activity program and a cognitive behavioral approach to increase the likelihood of long-term adherence. The behavioral intervention template incorporated the Diabetes Prevention Program and the Look AHEAD trial materials. The OTRP is consistent with national recommendations for the management of overweight and obesity in adults, but with embedded features designed to identify patient characteristics that might help predict outcomes, assure long-term follow up and support various research initiatives. Our goal was to develop approaches to understand whether there are patient characteristics that predict treatment outcomes.

A retrospective study on how primary care providers manage specialists' recommendations after an e-consultation

Introduction:

E-consultations are asynchronous text-based consultations between providers which can facilitate patient access to timely specialty care. In contrast to traditional face-to-face consults, conveying and completing recommendations of the specialist is the responsibility of the referring provider. This presents a new workflow for primary care providers who have multiple options (face-to-face, telephone, letter, secure message) to communicate the e-consultation recommendations. This study examines how primary care providers are managing this new workflow.

Methods:

We performed a retrospective random sampling of e-consultations with individual medical record review and classified e-consultations by type of recommendation, how recommendations were communicated to patients, and whether recommendations were carried out.

Results:

We randomly selected 220 e-consultations in 13 different specialties for review. In all, 85% of e-consultations contained recommendations for referring providers. Recommendations on medication(s) were most common (35%) followed by recommendations on ordering laboratory tests (29%). In all, 25% of the time e-consultants gave multiple possible courses of action for referring providers to choose from. Patient notification of recommendations was found for 192 (87%) of e-consultations with providers performing the notification 63% of the time and nursing staff performing the notification 37% of the time. The communication back to the patients included communication via nurse telephone calls (37%), provider telephone calls (23%), secure messages (24%), face-to-face visits (11%), and by written correspondence (5%).

Discussion:

Managing recommendations from e-consultations results in a new workflow for primary care providers. Healthcare institutions that utilize e-consults should be aware of this new workflow. Further study is needed to determine best practices for this task that is now increasing in primary care.

Biomechanical testing of the reconstructed ulnar collateral ligament: a systematic review of the literature

PURPOSE

The purpose was to perform a systematic review of the literature investigating biomechanical studies of ulnar collateral ligament reconstruction (UCLR) techniques to summarize the most commonly analyzed methods of fixation (at both the ulna and humerus), the degree of elbow flexion at the time of fixation, graft characteristics, and modes of failure with these techniques.

MATERIALS AND METHODS

A systematic review was performed. All cadaveric biomechanical studies that tested a reconstruction method for UCLR were included. Descriptive statistics were calculated for each study and parameter/variable analyzed.

RESULTS

Twenty-three studies were included with a total of 397 elbows in 242 cadavers (mean age 54.8 ± 20 years, range 16-96). The majority of studies (65 %) used a palmaris longus graft. The docking technique (37.2 %) was the most commonly tested reconstruction method. Significant heterogeneity between studies precluded assimilation of specific techniques (each of the 23 studies utilized a unique technique). Fixation was performed at 30°-90° of elbow flexion. The most common mode of failure was suture failure (51 %), followed by midsubstance rupture (27.00 %), and bone tunnel fracture (14.00 %). No significant differences were observed amongst techniques for all measures analyzed.

CONCLUSION

This study found the docking technique to be the most commonly tested technique, while the mode of reconstruction failure was most commonly at the suture interface. If the graft failed at the bone interface, it was most likely to occur at the ulna. Surgeon preference and comfort level with a specific technique should dictate choice.

Clinical outcomes of proximal row carpectomy versus four-corner arthrodesis for post-traumatic wrist arthropathy: a systematic review

We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I-III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate.

[Treatment costs for anterior cruciate ligament reconstruction: procedure related cost analysis in an university hospital]

BACKGROUND

Complex procedures in knee surgery, such as anterior cruciate ligament (ACL) reconstruction with the double bundle technique are not specially recognized within the German diagnosis-related groups (G-DRG) system. Hence, the goal of the present study was to perform a cost unit calculation and evaluate how ACL reconstruction in single versus double bundle techniques is remunerated.

PATIENTS AND METHODS

In 30 patients ACL reconstruction was performed with the single bundle technique (group A) and in 21 an anatomic double bundle reconstruction (group B) was performed. All costs including those for human resources, implants and materials, as well as general costs for administration and facilities were calculated.

RESULTS

All cases entered one DRG category, the I30Z "complex procedures at the knee joint". Thus, the revenue in 2008 was 2,996.65 euro per case and in 2009 3,120.35 euro per case. Calculating all costs, the profit contributions in 2008 and 2009 were 592,42 euro and 716,12 euro, respectively for group A. However, in group B the profit contributions were 314,68 euro and 438,38 euro, respectively.

CONCLUSION

Performing the double bundle technique for ACL reconstruction in a university hospital setting, significant cost reductions are needed to achieve the revenue generated by the single bundle technique. Additional changes of the relative weighting in the DRG are also necessary.

Graft repair of the peroneal nerve restores histochemical profile after long-term reinnervation of the rat extensor digitorum longus muscle in contrast to end-to-end repair

Declining motor function is a prominent feature of ageing physiology. One reason for this is a reduction in plasticity that normally compensates for ongoing reorganization of motor units under physiological conditions. Previous work from our laboratory has shown that microsurgical repair of the transected peroneal nerve is followed by considerable changes in the histochemical profile of the reinnervated extensor digitorum longus (EDL) muscle and that these changes are dependent on both the time and the type of nerve repair. At 6 months postoperatively, a trend toward reversibility could be discerned. In the present work, we analysed the long-term reorganization of histochemical motor unit distribution patterns 15 months after performing either end-to-end repair or grafting of the peroneal nerve in 3-month-old rats. In addition, the EDL muscles of an age-matched control group (age 18 months) were analysed for age-dependent changes. We observed a loss of histochemical organization of motor units leading to an additional fibre type (SDH-INT) in the control group. Fifteen months after end-to-end repair, the histochemical profile showed a decrease in fibre type IIA and an increase in fibre type SDH-INT (P < 0.05), indicating a profound histochemical disorganization of motor units. In contrast, nerve grafting largely restored the histochemical profile of reinnervated EDL muscles. Fibre type grouping was present after both types of nerve repair. These findings show that reorganization of the histochemical profile in reinnervated muscles is dependent on the time and type of nerve repair and is long lasting. In this study, grafting provided superior results compared with end-to-end repair. These long-term results after peripheral nerve repair are influenced by age-dependent changes. Accordingly, nerve repair reduces the normal functional plasticity of motor unit organization. This reduction is enhanced by increasing age.

Recognition of herpes simplex virus type 2 tegument proteins by CD4 T cells infiltrating human genital herpes lesions

The local cellular immune response to herpes simplex virus (HSV) is important in the control of recurrent HSV infection. The antiviral functions of infiltrating CD4-bearing T cells may include cytotoxicity, inhibition of viral growth, lymphokine secretion, and support of humoral and CD8 responses. The antigens recognized by many HSV-specific CD4 T cells localizing to genital HSV-2 lesions are unknown. T cells recognizing antigens encoded within map units 0. 67 to 0.73 of HSV DNA are frequently recovered from herpetic lesions. Expression cloning with this region of DNA now shows that tegument protein VP22 and the viral dUTPase, encoded by genes UL49 and UL50, respectively, are T-cell antigens. Separate epitopes in VP22 were defined for T-cell clones from each of three patients. Reactivity with the tegument protein encoded by UL21 was identified for an additional patient. Three new epitopes were identified in VP16, a tegument protein associated with VP22. Some tegument-specific CD4 T-cell clones exhibited cytotoxic activity against HSV-infected cells. These results suggest that herpes simplex tegument proteins are processed for antigen presentation in vivo and are possible candidate compounds for herpes simplex vaccines.

Clearance of HSV-2 from recurrent genital lesions correlates with infiltration of HSV-specific cytotoxic T lymphocytes

The mechanisms involved in host clearance of symptomatic mucocutaneous herpes simplex virus (HSV) infection are unclear. We studied the functional properties of bulk cultures of skin-infiltrating lymphocytes from normal skin and serial biopsies of recurrent genital HSV-2 lesions, and compared HSV-specific and NK responses with viral clearance. HSV-specific CD4+ or CD8+ T cells were rarely detected in lymphocytes cultured from normal skin. The total lymphocyte count and HSV-specific and NK-like effector cell activities were markedly higher in cultures derived from lesional skin. HSV-specific CD4+ proliferative responses and NK-like cytotoxic responses were present at all stages of herpetic lesions, including biopsies early in the disease course. In contrast, cytotoxic T lymphocyte activity was generally low among cells derived from early culture-positive lesions, and increased during lesion evolution. Viral clearance from the lesion site was associated with a high level of local cytolytic activity towards HSV-infected cells. The phenotypes of cells with HSV-specific cytotoxic responses varied between patients, having CD4+ and CD8+ components. Immunotherapeutic approaches to HSV should be directed at improving in vivo cytolytic activity to HSV.

Is sex of fetus associated with duration of labor in nulliparas?

In a post facto study to examine whether sex of fetus was related to duration of nulliparas' labor 30 nulliparous (had not given birth previously) women who delivered boys and 30 others who delivered girls were matched according to the criteria that they were nulliparous, received an epidural for analgesia during labor, and their labors were either induced or augmented. All delivered vaginally. Duration of labor was not statistically significantly related to sex of the fetus.

Vascular delay in skeletal muscle: a model for microcirculatory studies

Dynamic myoplasty is a relatively new use for muscle flaps and has led us to revisit the mechanisms of vascular delay as a means of optimizing blood supply to muscle flaps. Despite the well-documented effectiveness of vascular delay in skin flaps, vascular delay in muscle flaps has not been widely reported. Regardless of the many mechanisms postulated in the literature as contributors to the delay effect in skin, the one element common to all these hypotheses is the importance placed on changes in the microcirculation. Based on this factor, in the present study we developed and validated an animal model in which delay-induced microvascular changes could be measured in skeletal muscle flaps. We used the hairless mouse latissimus dorsi muscle flap because its vascular distribution is similar to that of humans and its thin structure will enable us in future studies to directly view and measure its microvasculature using videomicroscopy. In 12 animals, we found that delay significantly (p < 0.01) reduced necrosis of the distal part of the muscle from 57 +/- 9 percent in nondelayed flaps (n = 7) to 22 +/- 3 percent in delayed (n = 5) flaps. In these studies, we also determined that the hairless mouse latissimus dorsi muscle flap will serve as an excellent model for defining microvascular changes throughout delay.

Mortality of captive British wartbiter crickets: implications for reintroduction programs

A fungal infection was identified as the cause of a high mortality rate of captive wartbiter cricket (Decticus verrucivorus) nymphs at the London Zoo (United Kingdom) in 1994. This species is threatened with extinction in the United Kingdom and the animals concerned were part of a captive breeding and reintroduction program. Following these findings, reintroductions were postponed and release sites were used only where there were no extant wartbiter crickets.

Comparison of the effects of commonly used wound agents on epithelialization and neovascularization

BACKGROUND

The primary effect sought with most topical wound therapy is antimicrobial. Topical wound agents are thought to promote normal healing by protecting the wound from infection. In this study, we examined the effect of six commonly used topical wound agents (bacitracin, sodium hypochlorite, silver nitrate, silver sulfadiazine, mafenide acetate, and povidone-iodine) on epithelialization and neovascularization in noninfected wounds. For this study, a new wound model was used in which direct visualization and quantification of wound epithelialization and neovascularization were carried out throughout the entire healing process.

STUDY DESIGN

We measured the effect which 500 U per g of bacitracin, 0.25 percent of sodium hypochlorite, 0.5 percent silver nitrate, 1 percent silver sulfadiazine, 8.5 percent mafenide acetate, and 10 percent povodione-iodine had on the rate of wound epithelialization and neovascularization. The agents were applied topically to 99 circular full-thickness wounds (2.25 mm diameter, 0.125 mm depth) created on the dorsum of male hairless mouse ears. This model enabled us to visualize and measure directly wound epithelialization and neovascularization repeatedly throughout healing, using intravital video microscopy and computerized digitized planimetry.

RESULTS

Control wounds and wounds treated with silver sulfadiazine (n = 18) and mafenide acetate (n = 14) epithelialized in 7.2 +/- 0.7, 7.1 +/- 0.3, and 7.3 +/- 0.3 days, respectively. This was significantly (p < 0.01) faster than the wounds treated with povidone-iodine (n = 10), sodium hypochlorite, (n = 8), and bacitracin (n = 13). Wounds treated with povidone-iodine epithelialized the slowest (11.8 +/- 0.55 days). Wound neovascularization was completed most rapidly in the groups treated with povidone-iodine and silver sulfadiazine (15.0 +/- 0.4 and 15.3 +/- 0.7 days, respectively). This was significantly (p < 0.05) faster than wounds treated with silver nitrate (n = 15), which neovascularized in 18.4 +/- 0.56 days. One-half of the wounds treated with sodium hypochlorite (eight of 16) did not epithelialize or neovascularize.

CONCLUSIONS

The various antimicrobial agents studied in our in vivo model affect wound epithelialization and neovascularization differently. These effects on these two very important aspects of healing should be taken into consideration when indicating a specific agent for treatment of different types of wounds.

Direct visualization and measurements of wound neovascularization: application in microsurgery research

Neovascularization or angiogenesis is an essential yet poorly understood component of the healing process. In wound healing research, there is a lack of models enabling quantitative and continuous measurements of wound neovascularization. The hairless mouse ear wound model permits quantitative measurements of wound epithelialization and neovascularization continuously throughout the healing process. On the ears of male homozygous (hr/hr) hairless mice, standardized circular full thickness dermal wounds are produced; then, using vital microscopy, these two processes are directly viewed and measured at day 0 and every third day thereafter until these are complete. This model system and its application to clinically relevant situations are reviewed.

Microcirculation research, angiogenesis, and microsurgery

Angiogenesis, the formation of new blood vessels, is essential to a variety of normal and pathologic processes such as wound healing and tumor growth. In microsurgery the development of new vessels between the transferred tissue and the recipient bed is critical to the final outcome of the reconstruction. Several experimental models have been previously developed to study angiogenesis and the effect that new substances have on regulating this process, but they lack the ability to make quantitative measurements. Therefore, we have developed an animal model using the homozygous (hr/hr) hairless mouse ear; by using intravital microscopy and computer-assisted analysis, angiogenesis can be quantitatively measured. Using this model we showed that basic fibroblast growth factor and transforming growth factor beta significantly increased total vessel length by 32% and 63%, respectively, during 20 days following subcutaneous injection. In this paper the importance of angiogenesis research to reconstructive microsurgery is presented and discussed.

Attenuation of facial muscle spasticity with intramuscular phenol neurolysis

Intramuscular phenol neurolysis is a well-known procedure used to decrease spasticity and improve function in patients who have failed to respond to more conservative forms of intervention. Traditionally, this approach has been limited to spasticity reduction in limb muscles, and its use in managing spasticity of the facial muscles has not been described in the literature. This case report describes a new and previously unreported application of intramuscular neurolysis for managing severe unrelenting facial muscle spasticity in a postanoxic encephalopathic patient. Prior to the procedure, hypertonicity in the orbicularis oris muscle was so profound that it limited speech and affected cosmetic, hygienic, and nutritional status. After intramuscular phenol neurolysis of the orbicularis oris muscle, the patient's level of functioning improved.

Rehabilitation of physically disabled dentists: a model for a vocationally specific rehabilitation program

A unique collaborative program whose goal is to facilitate the return of disabled dentists to active dental practice is described. This approach includes comprehensive interdisciplinary evaluation and remediation, and it has succeeded in revealing previously undiagnosed impairments which should be considered in the formulation of a rehabilitation plan. A case report illustrates the process. This program can serve as a model for similar programs addressing the needs of other disabled health care professionals.

Selected opioids modify intake of sweetened ethanol solution among female rats

Water-deprived female rats were given a daily, 1.5-hr opportunity to take either a sweetened ethanol solution or water. Across days, they increased their intake of ethanol solution and had stable intakes of about 2 g of pure ethanol/kg after 3 weeks. Morphine (1.0 mg/kg) alone, and in combination with diprenorphine (25 micrograms/kg), increased intake of ethanol solution among females similar to the increased intake seen with males under similar procedures. Fentanyl dose-relatedly increased intake of ethanol. The data strengthen the idea that one or more of the endogenous opioid systems, but not all, are involved with instances of "excessive" intake of alcoholic beverages.

Primary amyloidosis with diffuse splenic infiltration presenting as fulminant pneumococcal sepsis

This case illustrates a unique clinical presentation of primary systemic amyloidosis, namely, overwhelming pneumococcal sepsis. Although there exists a well-established association between hyposplenism and overwhelming bacterial infection, amyloid replacement of the spleen as a primary cause of the hyposplenism has not been reported. Functional hyposplenism in regard to the effect of the spleen on erythrocytes has been reported in cases of diffuse splenic amyloid infiltration. The patient described had a fulminant course and associated disseminated intravascular coagulation, two clinical features more commonly seen in pneumococcemia occurring in asplenic patients as opposed to patients with normal splenic function. He had no predisposing factors, other than amyloid replacement of the spleen, to account for the development of overwhelming pneumococcemia. The immunologic function of the spleen in protection against overwhelming bacterial infection is briefly discussed.