Amputation Site Research Articles

Pain Management in a Case of Severe Electrocution Injury and Resultant Quadruple Amputation

Background: A 33-year-old patient presented to the Oxford Centre for Enablement for rehabilitation following severe electrical burn injuries requiring bilateral below elbow amputations, right below knee amputation and a left midfoot amputation. Specific issues: Chronic pain at the amputation sites as well as phantom limb initially proved challenging to manage medically however were eventually controlled with careful consideration of analgesic regimens. Pain was measured using the Numeric Pain Rating Scale. A likely attributing cause for the pain was peripheral neuropathy. Management: A combination of neuropathic agents and opioids helped to control pain. These analgesic included amitriptyline, gabapentin, pregabalin, tramadol and morphine in various regimens. Paracetamol and ibuprofen were also used. Implications: Rigorous search strategies were created which interrogated the MEDLINE, EMBASE, CINAHL, PsycINFO databases for studies reporting limb pain management in electrocution injuries. A total of 841 studies were found with 583 screened after removal of duplicates. No RCTs could be identified investigating limb pain management in electrical injuries. Case reports and case series have described various treatment options including nerve blocks, neuropathic analgesia, physiotherapy, botulinum toxin, fracture fixation and even the use of Virtual Reality headsets. We discuss this available evidence. No consensus exists as to the optimum management approach of pain in such patients. From our experience with this patient we suggest that a multi- modal analgesic approach is likely to be needed in such patients and should therefore be considered. Level 1 research into pain management in electrocution injuries is required.

Compound Clear Cell Sarcoma of the Skin-A Potential Diagnostic Pitfall: Report of a Series of 4 New Cases and a Review of the Literature.

The proliferation of cells with melanocytic lineage and a nested pattern has traditionally been regarded as a characteristic feature of a wide range of benign and malignant melanocytic proliferations. Herein, we report a series of 4 clear cell sarcomas, including 3 primary cutaneous and 1 metastatic to the skin, associated with a clear-cut intraepidermal proliferation of tumor cells representing a serious potential diagnostic pitfall. All patients were male individuals, aged from 17 to 71 years (mean: 42 y). The size of the tumors ranged from 8 to 55 mm (mean: 22.2 mm, median: 13 mm). Two tumors arose on a lower extremity and 1 each on the scalp and chest. Cutaneous metastasis developed on the limb proximal to the amputation site. Histologically, all tumors were variably circumscribed nodular or multinodular proliferations within the dermis, focally extending into the subcutis. They were composed of nests and fascicles of pale spindled and epithelioid cells with finely granular or pale cytoplasm, elongated nuclei with a single prominent nucleolus, featuring mild nuclear pleomorphism, and surrounded by delicate fibrous septa. Scattered wreath-like giant cells were present in all cases. Mitotic activity was low (mean and median: 3.5 mitoses/mm). The intraepidermal component consisted in all 4 cases of nests of tumor cells localized at the dermal-epidermal junction. Nests were well-defined and composed of spindled or epithelioid cells with irregular hyperchromatic nuclei, prominent nucleoli, and scant to moderately abundant eosinophilic to pale cytoplasm. Lentiginous proliferation of epithelioid tumor cells was coupled with focal upward migration of isolated tumor cells in a single case. By immunohistochemistry, all tumors were S100 protein, melan A, and HMB45 positive. By fluorescence in situ hybridization analysis, 3 tumors displayed rearrangements in the EWSR1 gene, whereas reverse transcriptase polymerase chain reaction confirmed EWSR1(e8)/ATF1(e4) translocation in the remaining case. In conclusion, an epidermal component in primary cutaneous clear cell sarcomas, or cutaneous metastasis of the tumor, is exceptional and represents a potential diagnostic pitfall. Careful attention to the salient morphologic features in the dermal component of the tumor, as well as confirmation of EWSR1 gene rearrangement by fluorescence in situ hybridization or reverse transcriptase polymerase chain reaction, is necessary for correct recognition of the tumor and to avoid erroneous diagnosis of a benign or malignant melanocytic proliferation.

Evaluation of Wound Closure Rates Using a Human Fibroblast-derived Dermal Substitute Versus a Fetal Bovine Collagen Dressing: A Retrospective Study

A retrospective study was conducted to evaluate the proportion of patients healed and time to healing of DFUs treated with a human fibroblast-derived dermal substitute (HFDS) or a fetal bovine collagen dressing (FBCD). Data from patients with a DFU who received the first treatment in 2014 were extracted from the electronic record database of 93 wound care centers. Baseline demographics (eg, age, gender, body mass index, and number of wounds); wound location, size, and duration; and wound-specific information such as wound size and number of and interval between applications were obtained. Study criteria stipulated patients who received at least one treatment in 2014 with HFDS or FBCD on a DFU with location coded as foot, toe, heel, metatarsal head, toe web space, toe amputation site, or transmetatarsal amputation site; ulcer size ≥1 cm2 to <20 cm2; and ulcer area reduction ≤50% in the 28 days before the first treatment with HFDS or FBCD were eligible for inclusion. Wounds that received an alternate skin substitute treatment up to 28 days before or concurrent with the first HFDS or FBCD treatment or if patient data that lacked baseline or follow-up wound area measurement were excluded. Deidentified data were extracted directly into data files and transferred to a third-party data management and statistical group for analysis. The frequency of DFUs achieving wound closure (defined as area ≤0.25 cm2) by weeks 12 and 24 and median time to wound closure of wounds that healed were analyzed. Baseline characteristics were compared using 2-sample t tests for continuous variables and 2-tailed Fisher's exact tests for difference in proportions between treatments. Frequency of and median time to wound closure were determined by Cox proportional hazards analysis. The frequency of wounds closed at 12 and 24 weeks, median time to wound closure, hazard ratio with 95% confidence interval, and P value were estimated from the Cox model. Statistical significance was defined as P <.05. Records showed 206 patients with 208 DFUs received treatment (108 HFDS, mean age 60.2 years, mean wound duration 8.8 months; 100 FBCD, mean age 65.2 years, mean wound duration 12.8 months) and were included. Mean number of treatment applications was 4.5 and 2.4 for HFDS and FBCD, respectively. After 12 and 24 weeks 44 (41%) and 69 (64%) of HFDS-treated wounds, respectively, and 21 (21%) and 43 (43%) of FBCD-treated wounds, respectively, were healed (at 12 weeks, P = .03; at 24 weeks, P = .03, log rank 2-tailed test, unadjusted). Median time to wound closure for HFDS and FBCD was 14.6 and 25 weeks, respectively (P = .03; log rank, 2-tailed test; Kaplan-Meier analysis). HFDS treatment significantly increased the probability of wound healing compared to FBCD treatment in the Cox proportional hazards analysis after adjusting for treatment terms, baseline wound area, baseline wound duration, baseline wound depth, wound location, and patient age at first treatment (HR = 1.77; 95% CI: 1.06-2.97; P = .03). DFU wounds are more likely to heal when treated with HFDS than with FBCD as used by facilities in this database. Studies examining the efficacy, cost-effectiveness, and patient-centered outcomes of these treatments is warranted. .

The Microsurgical Calcaneus Osteocutaneous Fillet Flap After Traumatic Amputation in Lower Extremities: Flap Design and Harvest Technique.

Attempts to salvage upper and lower extremities have performed more frequently in recent decades, although there are clear cases that cannot be salvaged. The purpose of this retrospective study was to present our experience in using free calcaneus osteocutaneous fillet flap for preserving below-knee amputation stump after traumatic amputations or functional preserving after nonsalvageable lower extremities. Between January 2012 and May 2017, 11 free calcaneus osteocutaneous fillet flap were used to preserving or lengthening below-knee amputation stump secondary to amputation on 8 males and 3 females. Patients' information and postoperative data were collected, including age of patient, sex, amputation site, flap survival, sensation recovery, and number of complications. All amputations were trauma related and secondary to motor vehicle accidents (n = 8) and industrial accidents (n = 3). The age of the patients ranged from 16 to 59 years, with a mean of 34.4 years. Free calcaneus osteocutaneous fillet flap were designed and harvested from all patients. All flaps survived and 2 complications developed in 2 patients. Nine of 11 patients obtained protective sensory recovery during the period of follow-up. The free calcaneus osteocutaneous fillet flap harvested from the amputated limb provides reliable and robust tissue for reconstruction of large defects of the residual limb without additional donor-site morbidity.

Adipose Stem Cell Therapy for Amputation Site Soft Tissue Restoration: A Prospective, Randomized Controlled Clinical Trial

Adipose Stem Cell Therapy for Amputation Site Soft Tissue Restoration: A Prospective, Randomized Controlled Clinical Trial

Healing and Mortality Rates Following Toe Amputation in Type 2 Diabetes Mellitus.

This single-centre study aimed to determine healing, re-ulceration, re-amputation and mortality rates at one year after toe amputations in patients with type 2 diabetes (T2DM). Eighty-one participants with T2DM admitted for toe amputation were included. Patient characteristics, peripheral circulation and neuropathy status were recorded. Subjects were then followed every 3 months post-amputation for a year. Overall, 59.3% of participants underwent further surgery (n=31 to revise the original amputation site and n=17 to amputate a new site). During 12 months, 45.7% of participants presented with a new ulcer at a different site. Mortality was 7.4%. In 12.4% of participants, the amputation site remained incompletely healed. Only 20.9% had no complications in 12 months. At 12 months, 80.2% of study cohort had a completely healed amputation site. In conclusion, this study highlighted high re-intervention, re-amputation and new ulceration rates. Strategies to improves these outcomes in such high-risk patients are warranted.

PC162. Major Limb Amputations in Patients With Congenital Vascular Malformations

The need for major amputations in patients with vascular malformations is rare. This study reviews our experience with major amputations in patients with vascular malformations. A retrospective review from April 2014 to November 2018 identified 993 patients undergoing management of a vascular malformation involving the upper or lower extremity at a tertiary center. This population was investigated for clinical course, surgical procedures, and outcomes. Five patients (0.5%) underwent major amputation, including three transhumeral and two above-knee amputations. The median age was 37.8 years (interquartile range [IQR], 25.4-40.2 years), and two (40%) were male. Four (80%) patients had high-flow arteriovenous malformations, including one (20%) with Parkes Weber syndrome. One (20%) patient had a low-flow venous malformation associated with Klippel-Trénaunay syndrome. All patients had malformation extending into the chest or pelvis, and amputation was initially thought to be unfeasible because of the proximal extent of the lesions. Before amputation, a median of 11 procedures (IQR, 4-39) were performed per patient. This included 29 transarterial embolizations, 4 transvenous embolizations, 19 direct stick embolizations, 3 debulking procedures, 38 débridements, 6 skin grafts or muscle flaps, and 4 minor amputations. The median time course of treatment before amputation was 117 months (IQR, 44-171 months). Indications for major amputation included chronic pain and recurrent bleeding in all five (100%) patients, loss of function in two (40%), nonhealing wounds in two (40%), and sepsis in one (20%) patient. There were no perioperative deaths. Median blood loss was 1000 mL (IQR, 650-2750 mL). All patients required transfusion of packed red blood cells with a mean of 1.6 units (standard deviation, 0.54 unit). Transhumeral amputation was facilitated by transcatheter embolization in one (33%) and an occlusion balloon within the subclavian artery in two (66%) patients. The median length of stay was 6 days (IQR, 5-13 days). Median length of follow-up was 132 months (IQR, 68-186 months) from initial intervention and 12 months (IQR, 8-31 months) from amputation. Two patients (40%) who had undergone transhumeral amputation required revision of the amputation site for recurrent ulceration at 2 and 38 months. Of these, one patient underwent three transcatheter embolization procedures before revision, and one underwent one embolization after revision. Although rare, successful amputation can be performed in select patients with refractory complications of vascular malformations including intractable pain, bleeding, and nonhealing wounds. Specific preoperative and intraoperative measures may be critical to achieve satisfactory outcomes, and endovascular techniques continue to play a role after amputation.

Complex Lower Extremity Wound in the Complex Host: Results From a Multicenter Registry.

Background:The complex diabetic lower extremity wound has not been well studied. There are a variety of new technologies now being applied with a paucity of evidence in evaluating their outcomes. The aim of this study is to describe clinical outcomes in the complex lower extremity wound in the comorbid host. We hypothesized that treatment choice would have minimal impact on healing outcomes in this compromised population.Methods:A multicenter retrospective registry of patients with diabetes and lower extremity wounds was created to compare treatment modalities of collagen–glycosaminoglycan scaffold, negative-pressure wound therapy, local tissue flap, and free tissue transfer. Statistical analyses included descriptive, proportional comparisons and Cox regression.Results:There were no statistical differences in age, hemoglobin A1c, or body mass index between groups. Study patients had a history of amputation (40.5%), peripheral vascular disease (54.6%), peripheral neuropathy (64.8%), end-stage renal disease (13.9%), renal/hepatic disease (40.4%), and hypertension (85%). The most common wound etiologies were surgical dehiscence (69%), diabetic neuropathic wounds (39%), and ischemic wounds (28%), most commonly located on the foot or at a prior amputation site (30%). Mean wound area was 57.9 cm2 and almost half with exposed bone. There were no statistical differences between treatment groups in proportion or time to healing, recurrence, or time to return to baseline function.Conclusions:Commonly used treatment modalities employed for this population of patients resulted in similar outcomes. This is the first study to describe the complex diabetic lower extremity wound in a complex host.

Risk Factors for Below-the-Knee Amputation in Diabetic Foot Osteomyelitis After Minor Amputation.

Below-the-knee amputation (BKA) can be a detrimental outcome of diabetic foot osteomyelitis (DFO). Ideal treatment of DFO is controversial, but studies suggest minor amputation reduces the risk of BKA. We evaluated risk factors for BKA after minor amputation for DFO. This is a retrospective cohort of patients discharged from Denver Health Medical Center from February 1, 2012, through December 31, 2014. Patients who underwent minor amputation for diagnosis of DFO were eligible for inclusion. The outcome evaluated was BKA in the 6 months after minor amputation. Of 153 episodes with DFO that met the study criteria, 11 (7%) had BKA. Failure to heal surgical incision at 3 months (P < .001) and transmetatarsal amputation (P = .009) were associated with BKA in the 6 months after minor amputation. Peripheral vascular disease was associated with failure to heal but not with BKA (P = .009). Severe infection, bacteremia, hemoglobin A1c, and positive histopathologic margins of bone and soft tissue were not associated with BKA. The median antibiotic duration was 42 days for positive histopathologic bone resection margin (interquartile range, 32-47 days) and 16 days for negative margin (interquartile range, 8-29 days). Longer duration of antibiotics was not associated with lower risk of BKA. Patients who fail to heal amputation sites in 3 months or who have transmetatarsal amputation are at increased risk for BKA. Future studies should evaluate the impact of aggressive wound care or whether failure to heal is a marker of another variable.

Nerve-mediated expression of histone deacetylases regulates limb regeneration in axolotls

Axolotls have amazing abilities to regenerate their lost limbs. Nerve and wound epidermis have great impacts on this regeneration. Histone deacetylases (HDACs) have been shown to play roles in the regeneration of amphibian tails and limbs. In this study, a bi-phasic up-regulation of HDAC1 was noted before early differentiation stage of axolotl limb regeneration. Limb regeneration was delayed in larvae incubated with an HDAC inhibitor MS-275. Local injection of MS-275 or TSA, another HDAC inhibitor, into amputation sites of the juveniles did not interfere with wound healing but more profoundly inhibited local HDAC activities and blastema formation/limb regeneration. Elevation of HDAC1 expression was more apparent in wound epidermis than in mesenchyme. Prior denervation prohibited this elevation and limb regeneration. Supplementation of nerve factors BMP7, FGF2, and FGF8 in the stump ends after amputation on denervated limbs not only enabled HDAC1 up-regulation but also led to more extent of limb regeneration. In conclusion, nerve-mediated HDAC1 expression is required for blastema formation and limb regeneration.

Self-reported Functional Status in US Service Members After Combat-Related Amputation.

The objective of this study was to describe the functional status of US service members after combat-related amputation. This was a cross-sectional analysis of data from a subsample of the Wounded Warrior Recovery Project, an ongoing, web-based, longitudinal examination of patient-reported outcomes of injured service members. The study sample included 82 Wounded Warrior Recovery Project participants with a combat-related lower extremity amputation who reported using a prosthetic device and completed the Orthotics and Prosthetics Users' Survey Lower Extremity Functional Status, which measures self-reported functional status in participants with a prosthetic device. Basic activities, such as walking indoors, getting on and off the toilet, and getting up from a chair, were reported by the majority of participants as "very easy/easy," whereas higher-level activities, such as climbing stairs, walking long distances, or running, were more often reported as "slightly difficult/very difficult" or "cannot do this activity." Functional status varied significantly by amputation site (unilateral below knee, unilateral above knee, or bilateral; P = 0.004), with significantly better function reported in those with unilateral below knee than bilateral amputation (P < 0.05). These findings highlight deficits in the functional status of US service members with combat-related amputation. Self-reported functional status of daily activities may help target important activities for patient-centered goals.

A retrospective analysis of tandoor burn injuries in Eastern Anatolia

Aims: This study was to determine the severity of the tandoor burns in a city in Eastern Anatolia and to attract attention for the prevention of tandoor burns. Subjects and Methods: A retrospective evaluation was made of the registration data of burns hospitalized. A record was made of patient variables including burn type, age, gender, socioeconomic status, and amputation site and level. Statistical Analysis Used: Descriptive statistics were used to summarize the data, and results were reported as number and percentage. Categorical variables were evaluated with the Chi-square test. P

Outcomes of Wound Healing and Limb Loss After Transmetatarsal Amputation in the Presence of Peripheral Vascular Disease

Transmetatarsal amputation (TMA) is the procedure of choice in treating forefoot gangrene and infection. Foot and ankle and vascular surgeons work closely together in limb salvage, but little is known about the timing of vascular intervention to achieve a healed amputation site. This study retrospectively looked at 153 patients with peripheral vascular disease who underwent TMA with a minimum of a 3-year follow-up. A total of 102 patients received vascular intervention: 79 endovascular and 23 open bypass. The primary focus of this study was to look at the timing of vascular intervention, incidence of wound healing, and incidence of limb loss. There was an overall 44% rate of limb loss. Patients who underwent open bypass did better than those who underwent endovascular intervention with a lower incidence of limb loss (87% compared with 51%), and quicker time to wound healing. The timing of vascular intervention, performed either before or after TMA, had no association with wound healing or limb loss. Similarly, the time interval between vascular intervention and TMA had no association with wound healing or limb loss. Comorbidities, including end-stage renal disease on hemodialysis, hyperlipidemia, and congestive heart failure, showed a significant association with TMA stump nonhealing and limb loss. Body mass index ≥30, end-stage renal disease on hemodialysis, and hyperlipidemia were all risk factors for limb loss.

Amputation-Site Soft-Tissue Restoration Using Adipose Stem Cell Therapy.

Soft-tissue deficits in amputation stumps can lead to significant pain and disability. An emerging treatment option is stem cell-enriched fat grafting. This is the first study assessing the potential for this treatment modality in lower extremity amputation sites. In this prospective cohort study, five injured military personnel suffering from pain and limited function at amputation sites were recruited. Fat grafting enriched with stromal vascular fraction was performed at amputation sites to provide additional subcutaneous tissue padding over bony structures. Outcomes measures included complications, demographic data, physical examination, cellular subpopulations, cell viability, graft volume retention, pain, Lower Extremity Functional Scale, Functional Mobility Assessment, 36-Item Short-Form Health Survey, and rates of depression. Follow-up was 2 years. There were no significant complications. Volume retention was 61.5 ± 24.0 percent. Overall cell viability of the stromal vascular fraction was significantly correlated with volume retention (p = 0.016). There was no significant correlation between percentage of adipose-derived stem cells or number of cells in the stromal vascular fraction and volume retention. There was a nonsignificant trend toward improvement in pain scores (3.0 ± 2.5 to 1.2 ± 1.6; p = 0.180 at 2 years). There were no significant changes in disability indexes. Results from this pilot study demonstrate that stromal vascular fraction-enriched fat grafting is a safe, novel modality for the treatment of symptomatic soft-tissue defects in traumatic lower extremity amputations. Volume retention can be anticipated at slightly over 60 percent. Further studies are needed to assess efficacy. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

Abstract B13: Perineural invasion in Ewing sarcoma—a novel mechanism and new therapeutic opportunities

Abstract Tumor dissemination and relapse are the major problems in Ewing sarcoma (ES) treatment, yet the mechanisms driving these processes are unknown. To elucidate the routes of ES metastatic spread, we used an orthotopic xenograft model. ES cells were injected into the gastrocnemius muscles of SCID/beige mice. Once the primary tumors reached the desired volume, they were excised by limb amputation. Subsequently, tumor dissemination was monitored by MRI and confirmed by histopathologic analysis. Interestingly, aside from typical hematogenous metastases, such as bone and lung lesions, we have also observed frequent perineural tumor dissemination manifested by the presence of migratory ES cells along the nerves adjacent to the primary tumors. This phenomenon was associated with formation of recurrent tumors at the amputation sites, as well as pelvic tumors with spine involvement. Interestingly, the level of perineural invasion (PNI) was dependent on the expression of neuropeptide Y (NPY) in ES cells. NPY is a neuronal protein released from peripheral sympathetic neurons, but also highly expressed in ES cells along with its receptors. The xenografts derived from ES cell lines not releasing endogenous NPY (TC71, TC32) exhibited frequent PNI in tumor-bearing limbs, as well as a high number of recurrent tumors at the surgery site and spine metastases (70% and 100% of mice with evidence of PNI for TC71 and TC32 xenografts, respectively). This phenomenon was less common in ES xenografts derived from NPY-rich SK-ES1 cells (17% of mice with signs of PNI). In line with these observations, NPY knockdown in SK-ES1 xenografts drastically accelerated formation of spinal tumors (60% of mice). Notably, in 40% of mice bearing SK-ES1/NPY shRNA xenografts the spinal tumors developed before the primary tumor growth was detectable at the site of ES cell injection. Thus, our in vivo experiments suggested that a lack of endogenous NPY in ES cells expressing high levels of its receptors triggers chemotactic effects of this peptide released from neighboring peripheral nerves, facilitating PNI. Indeed, in a transwell migration assay, NPY exerted significant chemotactic activity in SK-ES1/NPY shRNA cells, but not in the original SK-ES1 cell line. An even more profound chemotactic effect specific to the SK-ES1/NPY shRNA cells was observed with NPY-rich conditioned media obtained from neuroblastoma cells, which can serve as a model of peripheral sympathetic neurons. Further studies are required to determine which NPY receptors are responsible for its chemotactic properties. If the presence of perineural tumor growth is confirmed in human tumors, factors responsible for PNI in ES, e.g., NPY receptors, may become targets for novel therapies preventing disease dissemination and recurrence. Citation Format: Susana Galli, Sung-Hyeok Hong, Jason U. Tilan, Mina Adnani, Shiya Zhu, Yassi Fallah, Yi-Chien Lee, Olga Rodriguez, Chris Albanese, Ewa Izycka-Swieszewska, Joanna Kitlinska. Perineural invasion in Ewing sarcoma—a novel mechanism and new therapeutic opportunities [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr B13.

Osseointegrated Transcutaneous Device for Amputees: A Pilot Large Animal Model.

Traditional above-the-knee amputation prosthetics utilize a stump-socket interface that is well-known for skin/socket problems, sitting difficulty, disuse osteopenia, and increased work of ambulation. As a result, we evaluated a novel osseointegrated transcutaneous implant in a large animal. The implant was designed to promote osseointegration at the bone-implant interface and minimize complications. As proof of concept, four Dorset sheep underwent a two-stage surgery for forelimb placement of an osseointegrated transcutaneous implant utilizing Compress® technology (Biomet, Inc., Warsaw, IN). Two sheep received a long anchor plug (90 mm long x 9 mm in diameter) and two received a short anchor plug (46 mm long x 9 mm in diameter). Sixteen weeks after the initial surgery, the operative limbs, along with the attached implant, underwent radiographic and histological analysis for osseointegration. Periprosthetic fractures occurred in the two animals that received the longer internal prosthesis; one healed with splinting and the other animal underwent a second surgical procedure to advance the amputation site more proximal. No fractures occurred in the shorter internal prosthesis group. There was no histological evidence of infection and none of the transcutaneous adapters failed. Bone-implant osseointegration was demonstrated in two of three limbs that underwent histological analysis. This unique implant demonstrated osseointegration without transcutaneous adapter failure, all while displaying minimal infection risk from the outside environment. Although it involved short-term follow-up in a limited number of animals, this pilot study provides a platform for further investigation into the valid concept of using Compress® technology as an endo-exo device.

Inherent variations in the cellular events at the site of amputation orchestrate scar-free wound healing in the tail and scarred wound healing in the limb of lizard Hemidactylus flaviviridis.

Lizards are unique in having both-regeneration competent (tail) as well as non-regenerating appendages (limbs) in adults. They therefore present an appropriate model for comparing processes underlying regenerative repair and nonregenerative healing after amputation. In the current study, we use northern house gecko Hemidactylus flaviviridis to compare major cellular and molecular events following amputation of the limb and of the tail. Although the early response to injury in both cases comprises apoptosis, proliferation, and angiogenesis, the temporal distribution of these processes in each remained obscure. In this regard, observations were made on the anatomy and gene expression levels of key regulators of these processes during the healing phase of the tail and limb separately. It was revealed that cell proliferation markers like fibroblast growth factors were upregulated early in the healing tail, coinciding with the growing epithelium. The amputated limb, in contrast, showed weak expression of proliferation markers, limited only to fibroblasts in the later stage of healing. Additionally, apoptotic activity in the tail was limited to the very early phase of healing, as opposed to that in the limb, wherein high expression of caspase-3 was observed throughout the healing process. Early rise in VEGF-α expression reflected an early onset of angiogenesis in the tail, while it was seen to occur at a later stage in case of the limb. Moreover, the expression pattern of transforming growth factor beta members points toward a pro-fibrotic response being induced very early in the amputated limb. Collectively, these results explain why regenerating appendages are able to heal without scars and if we are to induce scar-free healing in nonregenerating limbs, what interventions can be envisaged. This is crucial to the field of regenerative medicine since it is the initial stages of repair following amputation, which decide whether the appendage will be restored or only covered with a scab.

Exogenous Vitamin D signaling alters skeletal patterning, differentiation, and tissue integration during limb regeneration in the axolotl

Urodele amphibians such as the axolotl regenerate complete limbs as adults, and understanding how the “blueprint”, or pattern, of the regenerate is established and manipulated are areas of intense interest. Nutrient signaling plays an important role in pattern formation during regeneration. Retinoic acid signaling is the most characterized pathway during this process. Exogenous retinoic acid (RA) reprograms the pattern information in regenerating cells to a more posterior, ventral, and proximal identity. Vitamin D signaling shares several molecular similarities with RA and has been shown to alter pattern formation during zebrafish pectoral fin regeneration. To determine if exogenous Vitamin D signaling is capable of reprograming pattern in the axolotl limb blastema, we treated regenerating limbs with a potent Vitamin D agonist. Under the studied conditions, exogenous Vitamin D did not act in a manner similar to RA and failed to proximalize the pattern of the resulting regenerates. The Vitamin D treatment did result in several skeletal defects during regeneration, including carpal fusions along the A/P axis; failure to integrate the newly regenerated tissue with the existing tissue, formation of ectopic nodules of cartilage at the site of amputation, and altered bone morphology in uninjured skeletal tissue.

Angiosome perfusion of the foot: An old theory or a new issue?

The angiosome concept of foot perfusion was conceived based on anatomical studies of arterial circulation and used for planning surgical procedures, tissue reconstruction, and amputation. Its application is relevant in diabetic patients with critical limb ischemia and nonhealing foot ulcer or amputation. An understanding of foot angiosome anatomy is useful for predicting healing and planning arterial revascularization. A review of the literature, including the most recent systematic reviews and meta-analyses, indicates improved wound healing is achieved when the angiosome concept is followed. The greatest value of angiosome-based revascularization is in patients with lesion(s) limited to a single angiosome, or to achieve optimal healing of amputation sites. Future research should focus on proper identification of (imaging) modalities to determine the hemodynamic and functional changes before and after revascularization, thus identifying the “real” angiosome and directing optimal therapy.

F68. Sensory abnormalities and ultrasound-verified neuromas in lower extremity amputees: An ongoing study

Introduction The role of neuromas in stump and phantom limb pain remains unclear. This ongoing study examines whether neuromas are more frequent in amputees experiencing spontaneous and evoked pain after lower extremity amputation than in amputees without pain. Methods In this observational cohort study, amputees with lower and upper extremity amputation are recruited. They answer pain questionnaires and undergo a clinical examination with sensory testing performed within the area of spontaneous pain. Testing includes mapping and registration of sensation elicited by brush, cold and heat (thermorolls 20 °C and 40 °C) and pinprick stimuli (60 g von Frey filament). Neuromas are identified using high resolution (6–18 MHz) ultrasound by an investigator blinded to the patients’ history of pain. Cross sectional areas of the neuromas are measured by the direct tracing method and shear wave elastography is performed. Pressure pain thresholds are measured by an hand held pressure algometer. Results So far, 45 lower and upper extremity amputees have participated in the study (29 men and 16 women; age 25–83 years). Seventy-three percent had at least one neuroma verified by ultrasound. All amputees experienced stump or phantom pain, and the pain was present at least once a month in 16 patients. Only four patients had pain on a daily basis. All amputees experienced abnormal sensations with either hypo- and/or hyperesthesia, and pinprick hyperalgesia was present in seven patients. No significant difference in prevalences of stump pain, intermittent phantom pain and spontaneous phantom pain in patients with and without ultrasound-verified neuromas.No significant difference in prevalence of hypo- or hyperesthesia, hyperalgesia, allodynia and occurrence of Tinel’s sign in patients with and without ultrasound-verified neuromas. Conclusion The recruitment is ongoing. Preliminary data show no association between the occurrence and severity of neither stump nor phantom pain and the presence of neuromas at the amputation site. Sensory abnormalities, pinprick hyperalgesia and brush- and/or cold-evoked allodynia are common findings at the site of the stump, regardless of the occurrence of neuromas.