Keisuke Takanari

Effects of lowering ambient temperature on pain-related behaviors in a rat model of neuropathic pain

Abstract. To clarify the mechanism by which changes in chronic pain are induced by cold environments, rats rendered neuropathic by a chronic constriction injury (CCI) to the sciatic nerve were exposed to low ambient temperature (LT; 7°C decrease from 22°C) in a climate-controlled room. LT exposure aggravated pain-related behaviors in CCI rats, i.e., decreased the threshold to von Frey hair and paw pressure stimulation, prolonged the duration of foot withdrawal to pinprick stimulation, and increased the cumulative duration of guarding posture. Lumbar sympathectomy (SYX) did not inhibit LT-induced augmentations of pain-related behaviors in CCI rats. LT exposure decreased the skin temperatures of both hind paws to the same degree in the sham-operated control and SYX rats, while in the CCI and SYX+CCI rats it caused a larger temperature decrease in the injured paw than in the uninjured one. These results indicate that LT exposure augments abnormalities in pain-related behaviors of neuropathic rats, and also suggest that sympathetic nervous activity is not a predominant factor in the augmenting mechanism.

Effects of lowering barometric pressure on guarding behavior, heart rate and blood pressure in a rat model of neuropathic pain

We investigated whether lowering barometric pressure by 20 mmHg (LP) aggravates the guarding behavior suggestive of spontaneous pain following sciatic nerve chronic constriction injury (CCI) in rats. Systemic blood pressure (BP) and heart rate (HR) of unrestrained rats were recorded telemetrically during LP both before and after the CCI surgery. CCI rats showed guarding posture in normopressure conditions, and LP increased the cumulative time of this behavior. Baseline BP but not HR was increased following CCI. LP increased BP and HR of the rats only before the CCI surgery. Animals after CCI surgery showed variable (BP, HR) and transient (HR) responses to LP. These results indicate that (1) LP aggravated spontaneous pain and increased BP and HR in the CCI rats, and (2) CCI surgery influenced BP and HR of rats.

Skin-derived precursor cells promote wound healing in diabetic mice.

BackgroundImpaired wound healing as one of the complications arising from diabetes mellitus is a serious clinical issue. Recently, various cell therapies have been reported for promotion of wound healing. Skin-derived precursor cells (SKPs) are multipotent adult stem cells with the tendency to differentiate into neurons. We investigated the potency of promoting diabetic wound healing by the application of SKPs. MethodsSkin-derived precursor cells isolated from diabetic murine skin were cultured in sphere formation medium. At passage 2, they were suspended in phosphate-buffered saline (PBS), and applied topically to full-thickness excisional cutaneous wounds in diabetic mice. Application of PBS served as controls (n = 21 for each group; n = 42 total).Time to closure and percentage closure were calculated by morphometry. Wounds were harvested at 10 and 28 days and then processed, sectioned, and stained (CD31, &agr;-smooth muscle actin, and neurofilament heavy chain) to quantify vascularity and neurofilaments. ResultsWounds treated with SKPs demonstrated a significantly decreased time to closure (18.63 days) compared with PBS-control wounds (21.72 days, P < 0.01), and a significant improvement in percentage closure at 7, 10, 14, and 18 days compared with PBS-control wounds (P < 0.01). Histological analysis showed that the Capillary Score (the number of vessels/mm2) was significantly higher in SKP-treated wounds at day 10 but not at day 28. Nerve Density (the number of neurofilaments/mm2) had increased significantly in SKP-treated wounds at day 28 compared with control group. Some applied SKPs were stained by neurofilament heavy chain, which demonstrates that SKPs directly differentiated into neurons. ConclusionsSkin-derived precursor cells promoted diabetic wound healings through vasculogenesis at the early stage of wound healing. Skin-derived precursor cells are a possible therapeutic tool for diabetic impaired wound healing.

Management of Postpneumonectomy Empyema Using Free Flap and Pedicled Flap

Treatment of empyema after pneumonectomy is challenging. We treated 4 patients with postpneumonectomy empyema using a free rectus abdominis myocutaneous flap together with a pedicled pectoralis major muscle flap. The pectoralis major flap was used to fill the apical portion of the cavity, while the rectus abdominis flap was used to fill the caudal portion and occlude any bronchial fistula present. All empyemas were treated successfully without recurrence. This method has the advantage of filling apical and caudal parts of the space at once, making effective use of the combined volume of the two flaps.

Differences in blood flow volume and vascular resistance between free flaps: assessment in 58 cases.

In free-flap transfer, blood flow in the transferred flap contributes to wound healing and to resistance against infection in the recipient site. Successful reconstructions using free tissue transfers may be required to define and choose flaps with abundant blood flow in necessary cases. We investigated blood flow in the flap by transit-time ultrasound flowmeter in 58 free-flap transfers. Flow volume was compared between flap tissues as vascular resistance in the flap was calculated. Fasciocutaneous and osteocutaneous flaps had relatively low blood flow volume, myocutaneous flaps had more, and intraperitoneal flaps had still higher blood flow volume. These differences were statistically significant. Vascular resistance significantly decreased in the same order of comparison. Our findings will help in selecting the most suitable flaps for reconstructive surgery.

Computed tomographic assessment of autologous fat injection augmentation for vocal fold paralysis: CT of Autologous Fat Injection Augmentation

To perform a quantitative computed tomography (CT) assessment of short‐ and long‐term outcomes of autologous fat injection augmentation in patients with unilateral vocal fold paralysis.

Relationship between BMI and Postoperative Complications with Free Flap in Anterolateral Craniofacial Reconstruction

Background: Although we have seen tremendous advancement in microsurgery over the last 2 decades and free tissue transfer has become standard for head and neck reconstruction, surgeons still struggle to prevent postoperative complications. We examined the relationship between body mass index (BMI) and postoperative complications in patients undergoing rectus abdominis free flap transfer after anterolateral craniofacial resection. Methods: This was a retrospective review of reconstructive surgery using rectus abdominis musculocutaneous free flap in patients with locally advanced maxillary sinus carcinoma from 2003 to 2014 (n = 35, 27 men and 8 women; average age, 60.9 ± 7.8 years). All patients underwent craniofacial reconstruction after anterior and middle cranial fossa skull base resection and maxillectomy (class IV, subtype a) with palatal resection. Patients were categorized based on sex, BMI, and other parameters. Results: Recipient-site infection occurred in 11 patients (31.4%), cerebrospinal fluid leakage in 6 (17.1%), partial flap necrosis in 2 (5.7%), total flap necrosis in 1 (2.9%), and facial fistula in 4 (11.4%). Women showed partial flap necrosis significantly more frequently (P = 0.047), probably owing to poor vascular supply of the subcutaneous fat layer. Patients with low BMI (<20 kg/m2) showed recipient-site infection (P = 0.02) and facial fistula (P = 0.01) significantly more frequently owing to insufficient tissue volume and poor vascular supply. Conclusion: Postoperative recipient-site infection and facial fistula occurred mainly in low-BMI patients. Surgeons should take care to achieve sufficient donor tissue on low-BMI patients. Using a prosthetic obturator in low-BMI patients for craniofacial reconstruction can be a good alternative option to reduce postoperative complications due to insufficient donor tissue volume.

Free calvarial periosteum graft vascularized by an omental flap in a rat model.

Because omental flaps are useful for flap prefabrication and the cambium layer of the periosteum can be osteogenic, we examined whether calvarial periosteum grafted onto greater omentum of rats was osteogenic and suitable for a flap. Distal omentum was wrapped with calvarial periosteum and so the cambium faced the omentum. Grafted omentum was harvested at 1 to 9 days. In other rats, grafted omentum was elevated as a pedicled flap and moved to the abdominal subcutis, to be harvested later at 1 to 5 months after the initial surgery. Bone formation was evaluated histologically, histochemically, and radiographically. On day 3, osteoid had formed. From day 4, calvarial periosteum was revascularized by omentum and bone was forming. New bone was maintained after grafting to subcutis for 5 months. Thus, bone formed by periosteum on the omentum could be used to reconstruct defects of the bone.

Long-term functional outcome of tibial osteomyelitis reconstruction with free tissue transfer

Reconstruction of lower extremity osteomyelitis remains a great challenge due to insufficient surrounding tissue volume, relatively less blood supply and daily stress to the site. Microsurgical reconstruction provides an efficient source of bone and soft tissues and has greatly contributed for the limb salvage rate.1,2 However to date, emphasis has been placed mainly on limb salvage and long-term functional outcomes have rarely been focused on. We retrospectively reviewed our cases where free tissue transfer was performed for the reconstruction of the tibial osteomyelitis and assessed postoperative outcome and functional outcomes of the patients. Nine patients who had undergone free flap reconstruction for tibial osteomyelitis in our hospital between 1990 and 2010 were assessed for postoperative course and functional outcome (Table 1). Lower extremity functional scale (LEFS)3 andVisual analoguescale (VAS) thatwereobtainedbypatientreportedquestionnairewereusedforassessmentof functional outcome. The original cause for the osteomyelitis included traffic accident, sport trauma, and other trauma. Therewere 2 Gustilo type II patients, 2 IIIA and 5 IIIB patients. The flaps utilized for reconstructionwerefibulaflap (FIB) for3patients, omental flap (OM) for 1, a combination of FIB and OM for 2, a combination of OM and iliac bone graft (IBG) for 2 and a combinationof anterolateral thighflapand IBG for 1patients. Mean postoperative follow-up period was 75.8 months. Two patients experienced flap loss both due to venous congestion and salvaged either by additional free flap or loco-regional flap. Four patients experienced wound dehiscence with/without infection and treated conservatively or additional debridement. All except one patient achieved complete bone union. All except one patient healed completely and no fistula or recurrence were seen. One patient developed recurrence of osteomyelitis, however she did not wish additional operation. The time to bone union ranged from 3 to 10 months (average 5.5 months) and the time to complete wound closure ranged from 2 to 50months (average 10.1 months). In LEFS assessment, patients had relatively high scores in daily activities including daily work, walking short distances, and doing light work. However, they tended to score lower in hard activities including walking long distance, running and jumping. The average percentage rating of LEFS was 78% (59 to 98%). The average score for pain VAS was 16 points (0 to 45/100 points). The correlation between LEFS score and the type of original fracture, between LEFS and VAS score, and between LEFS score and postoperative complication (infection, fistula and flap loss) was further assessed (Figure 1A–E). The original fracture type related to neither LEFS nor VAS score. Significant correlation was seen between LEFS and VAS score. The patient with lower VAS score marked higher LEFS score. There was a trend that patients without complication tend to mark high LEFS score and low VAS score, however no significant correlation was seen. With the improvement of the reconstruction for osteomyelitis, the patients who had previously been recommended for limb amputation can successfully be salvaged. Thus, it is increasingly important to assess the functional outcome and quality of the life after the salvage surgery for such patients. There are several reports that support limb salvage surgery versus amputation. In the systematic review for type IIIB and C injuries, there is no significant difference of functional outcome between amputation and limb salvage.4 Other study also demonstrates no difference of functional outcome between salvage group and amputation group, however overall cost of amputation is more expensive than limb salvage.5 Moreover, psychiatric symptoms and pain associated with the loss of their limb are still problems. In our case series, theonly patientwhohada recurrenceof osteomyelitis had the lowest rating. Among other patients with low rating, one had restriction of ankle motion, one had psychological problems and one had continuous pain. The incidence of the complication or the original trauma type did not relate to functional outcomes, however, LEFS score has a correlation to VAS score. The main restricting factor for limb function seemed pain which is related to the wound and scar formation. Thepatientwhoachievedwoundhealing can start rehabilitation and return to daily life earlier, consequently resulting in higher function. We believe that free flap reconstruction not only improves the limb salvage chance, but also improves the functional outcome of the patients by covering the wound faster and reducing postoperative pain.

Preoperative surgical simulation and validation of the line of resection in anterolateral craniofacial resection of advanced sinonasal sinus carcinoma

The purpose of this study was to assess the usefulness and accuracy of preoperative 3D virtual simulation of anterolateral craniofacial resection in cases of advanced sinonasal sinus carcinoma.