Persistence of the Antibacterial and Antiviral Effects after Skin Cleansing ~A New Approach to Suppress the Contact Infection~.

Handwashing represents an important personal hygiene measure for preventing infection. Herein, we report the persistence of antibacterial and antiviral effects after handwashing with fatty acid salt-based hand soap. To this end, we developed a new in vitro test method to measure persistence, utilizing coacervation formed by anionic surfactants and cationic polymers to retain highly effective soap components against each bacterium and virus on the skin. Coacervation with fatty acid salts and poly diallyldimethylammonium chloride (PDADMAC) as a cationic polymer allowed the persistence of antibacterial and antiviral effects against E. coli, S. aureus, and influenza virus even 4 h after handwashing. Furthermore, we confirmed an increase in the number of residual components effective against each bacterium and virus on the skin. In summary, the current findings describe an effective approach for enhancing the protective effects of handwashing.

Correlation between the Closure Time of Patent Ductus Arteriosus in Preterm Infants and Long-Term Neurodevelopmental Outcome.

In patent ductus arteriosus (PDA) in preterm infants, the relationship between treatment timing and long-term developmental prognosis remains unclear. The purpose of this study was to clarify the relationship between the age in days when ductus arteriosus closure occurred and long-term development. Preterm infants with a birth weight of less than 1500 g who were admitted to our NICU over a period of 9 years (2011-2019) and were diagnosed with PDA were included. A new version of the K-type developmental test for corrected ages of 1.5 and 3 years was used as an index of development. The relationship between the duration of PDA and the developmental index was evaluated using Pearson's correlation coefficient, and multiple regression analysis was performed. Development quotient (DQ) at the ages of 1.5 and 3 years showed a correlation with the PDA closure date and the standard deviation (SD) value of the term birth weight. Multiple regression analysis showed a positive correlation of the DQ at 1.5 and 3 years with the SD value of the term birth weight and a negative correlation with the PDA closure date. In addition, a stronger correlation was found in the "posture/motor" sub-item at 3 years. On the other hand, the analysis including preterm infants without PDA showed that preterm infants with PDA closure on the 6th day or later after birth had a significantly lower 3-year-old DQ than preterm infants with a PDA exposure within 5 days. In conclusion, it is suggested that the decrease in cerebral blood flow due to PDA in preterm infants has an adverse effect on long-term neurodevelopment. Appropriate interventions, including surgical treatment for PDA in preterm infants without delay, ideally within 5 days of birth, may be effective in improving the developmental prognosis.

Portal vein wedge resection and patch venoplasty with autologous vein grafts for hepatobiliary-pancreatic cancer.

BACKGROUND: Advanced hepatobiliary-pancreatic cancer often invades critical blood vessels, including the portal vein (PV) and hepatic artery. Resection with tumor-free resection margins is crucial to achieving a favorable prognosis in these patients. Herein, we present our cases and surgical techniques for PV wedge resection with patch venoplasty using autologous vein grafts during surgery for pancreatic ductal adenocarcinoma (PDAC) and perihilar cholangiocarcinoma (PhCC). CASE PRESENTATION: Case 1: 73-year-old female patient with PDAC; underwent subtotal stomach-preserving pancreatoduodenectomy, with superior mesenteric vein wedge resection and venoplasty with the right gonadal vein. Case 2: 67-year-old male patient with PDAC; underwent distal pancreatectomy and celiac axis resection, with PV wedge resection and venoplasty with the middle colic vein. Case 3: 51-year-old female patient with type IV PhCC; underwent left hepatectomy with caudate lobectomy and bile duct resection, with hilar PV wedge resection and venoplasty with the inferior mesenteric vein (IMV). Case 4: 69-year-old male patient with type IIIA PhCC; underwent right hepatopancreatoduodenectomy, with hilar PV resection and patch venoplasty with the IMV. All patients survived for over 12 months after the surgery, without local recurrence. CONCLUSIONS: PV wedge resection and patch venoplasty is a useful technique for obtaining tumor-free margins in surgeries for hepatobiliary-pancreatic cancer.

Crohn's disease-related anal fistula cancer diagnosed by examination under anesthesia: a case report.

BACKGROUND: As the number of patients with inflammatory bowel disease (IBD) increases, the incidence of IBD-related colorectal cancer (CRC) is also on the rise. Crohn's disease (CD)-related CRC has been reported to have a poorer prognosis than sporadic CRC, and the early detection of CD-related CRC is difficult. Japanese patients with CD are reported to have a higher frequency of anorectal cancer than the Western population; however, methods for early diagnosis have not yet been established because of perianal pain during the examination. CASE PRESENTATION: We report a case of CD-related anal fistula cancer that was detected early by surveillance examination under anesthesia (EUA). The patient was a 37-year-old man, diagnosed with CD at the age of 15 years and started medical treatment. However, due to poor disease control, the intestinal tract remained highly inflamed and the patient continued to have over 10 bowel movements per day. He was referred to our hospital for surgical treatment after a colonoscopy (CS), which revealed multiple active ulcers and stenoses. Since three perianal seton drainage tubes had been placed around his anus since the age of 33 years, we decided to perform an EUA to rule out cancer coexistence in the anorectal region. After a random biopsy of the rectum by CS under general anesthesia, we resected and curetted multiple perianal fistulas as much as possible and reinserted the seton drainage tubes. Pathological examination of the fistula tract revealed adenocarcinoma in one tract, indicating the coexistence of anal fistula cancer. Based on the diagnosis of multiple intestinal stenoses and anal fistula cancer due to CD, we performed hand-assisted laparoscopic total colectomy, rectal amputation, extensive perineal resection, and reconstruction using a left rectus abdominis flap. CONCLUSION: In a long-term CD patient with anorectal lesions, we performed an EUA to diagnose the coexistence of anal fistula cancer at an early stage, and surgical resection was achieved. EUA is effective for the early detection and treatment of CD-related CRC and may contribute to an improved prognosis.

Factors associated with the development of epilepsy in very low birth weight infants.

BACKGROUND: The survival rate of very low birth weight (VLBW) infants has recently improved. However, the occurrence of and factors associated with epilepsy in VLBW infants remain unknown. This study aimed to clarify the incidence, characteristics, and factors associated with epilepsy development in VLBW infants. METHODS: All VLBW infants admitted to our hospital between 2012 and 2017 were included in this study. VLBW infants with a follow-up period of <1 year were excluded. Chromosomal abnormalities, brain anomalies, severe intraventricular hemorrhage (IVH), cystic periventricular leukomalacia (PVL), and hypoxic ischemic encephalopathy (HIE) were considered to be risk factors. RESULTS: Epilepsy occurred in 21/526 (4.0%) VLBW infants. Chromosomal abnormalities, brain anomalies, severe IVH, cystic PVL, HIE, neonatal seizures, advanced maternal age, maternal diabetes mellitus, no administration of antenatal corticosteroids, and low Apgar scores at 1 and 5 min were associated with a risk of epilepsy. The median time to epilepsy onset was 8 months (range: 0-59 months), and the onset occurred within 2 years in 15/21 patients (71.4%) and within 4 years in 18/21 patients (85.7%). VLBW infants with risk factors developed epilepsy earlier and at a significantly higher rate than those without risk factors. Among infants who had risk factors and who developed epilepsy, 86.7% did so within 2 years of age, compared to 33.3% of those who developed epilepsy but did not have risk factors. CONCLUSION: These findings regarding factors associated with a risk of development of epilepsy and temporal feature of epilepsy may contribute to the development of monitoring and treatment protocols for epilepsy in VLBW infants.

[A Case Report-A Successful Case of Distal Pancreatectomy with En Bloc Celiac Axis Resection for Locally Advanced Pancreatic Cancer with an Aberrant Right Hepatic Artery].

In cases of pancreatic cancer with anatomical variations of the hepatic artery, it is important to evaluate the hemodynamics of each case for surgical indication. We report the case of a 68-year-old man with locally advanced pancreatic cancer and an aberrant right hepatic artery who underwent distal pancreatectomy with celiac axis resection(DP-CAR). He was admitted to our institute due to abdominal discomfort. A CT scan showed pancreatic cancer invading the common hepatic artery. He underwent chemoradiotherapy with a diagnosis of locally advanced pancreatic cancer. After the tumor downstaging, we performed DP-CAR, which included a gastroduodenal artery and a proper hepatic artery resection. Even though delayed gastric emptying was observed after the operation, he was discharged on postoperative day 36.

[FOLFIRI plus RAM Therapy in Later Line of Unresectable Colorectal Cancer].

FOLFIRI plus ramucirumab(RAM)therapy has been reported to be effective and safe in the RAISE trial as second-line treatment for unresectable colorectal cancer. It is hypothesized that RAM may be effective in patients with PD treated with FOLFIRI plus bevacizumab(Bev)due to different mechanism of action from that of Bev, which is also an angiogenesis inhibitor. From January 2017 to December 2021, we conducted a retrospective study of 6 patients who had PD with 5-FU, oxaliplatin, irinotecan, or Bev as first or second-line treatment at our institution and who received FOLFIRI plus RAM in later line treatment. The 6 cases consisted of 3 patients in the third-line treatment, 1 patient in the fourth-line treatment, and 2 patients in the sixth-line treatment. The anti-tumor effect was PD in all cases in the third-line and fourth-line treatment, but the 2 patients of sixth-line treatment were controlled diseases.

Clinical outcomes of single incision laparoscopic surgery for colorectal cancer: A propensity score-matched analysis between well-experienced and novice surgeons.

Background: Single incision laparoscopic surgery (SILS) is a recent advancement in minimally invasive techniques for colorectal cancer (CRC). However, SILS is a technically challenging procedure for novice surgeons. The aim of this study was to evaluate clinical outcomes of SILS for CRC performed by novice surgeons compared with those performed by well-experienced surgeons. Methods: We retrospectively analyzed 1004 consecutive patients with stage I-IV CRC who underwent SILS between May 2009 and December 2018, using propensity score-matched analysis. Results: After propensity score-matching, we enrolled 344 patients (n = 172 in each group). Before matching, significant group-dependent differences were observed in terms of age (P = 0.034) and tumor location (P < 0.001). After matching, preoperative clinical factors were similar between groups, but operative time was longer in the Novice group (213 vs 171 min, P < 0.001). Other operative factors and morbidity rates did not differ significantly between groups. The number of harvested lymph nodes was smaller in the Novice group (23 vs 25, P = 0.040), and the number of patients with lymph node metastases was smaller in the Novice group (57 vs 86, P = 0.002). The 3-year disease-free survival rate was 85.8% in the Novice group and 89.9% in the Experienced group (P = 0.512). Three-year overall survival rate was 92.2% in the Novice group and 90.0% in the Experienced group (P = 0.899). Conclusion: SILS for CRC was safely performed by novice surgeons under the guidance of well-experienced surgeons, and could provide satisfactory oncological outcomes.

TRESBIEN (OGSG 2101): encorafenib, binimetinib and cetuximab for early recurrent stage II/III BRAF V600E-mutated colorectal cancer.

The BRAF V600E mutation accounts for approximately 5% of colorectal cancer (CRC) cases and is an extremely poor prognostic factor. However, there are no clear recommendations regarding first-line therapy for patients with early recurrent BRAF V600E-mutated CRC, during or after adjuvant chemotherapy. Recently, a novel combination of encorafenib, binimetinib and cetuximab, showed a higher response rate than standard chemotherapy in patients with BRAF V600E-mutated CRC. Here we describe our plan for the TRESBIEN study (OGSG 2101), which is an open-label, multicenter, single-arm, phase II study designed to evaluate whether encorafenib, binimetinib and cetuximab are effective for patients with early recurrent BRAF V600E-mutated colorectal cancer, during or after adjuvant chemotherapy. The planned number of subjects is 25.

An ongoing study to evaluate encorafenib, binimetinib and cetuximab for people with early recurrent BRAF V600E-mutated colorectal cancer. BRAF V600E-mutated colorectal cancer (CRC) is a type of cancer caused by change (mutation) in a gene called BRAF. It is one of the most difficult types of CRC to treat because currently available drugs do not effectively treat the disease. Recently, two novel treatments, encorafenib and cetuximab, have been approved for use together in several countries for the treatment of advanced or metastatic BRAF V600E-mutated CRC. In Japan, these drugs are also approved to be given with another treatment called binimetinib, an approach called triplet therapy. This article describes the ongoing TRESBIEN study that is looking at how effective and how safe triplet therapy is for the treatment of people with early recurrent BRAF V600E-mutated CRC, during or after they have additional (adjuvant) chemotherapy. This study is ongoing, and the researchers are currently recruiting new participants. TRESBIEN will evaluate the percentage of participants whose tumors shrink with triplet therapy. The study will also look at any side effects. Clinical Trial Registration: jRCTs051210152 (ClinicalTrials.gov) (Japan Registry of Clinical Trials https://jrct.niph.go.jp/search?language=en&page=1).

Comparison of clinical outcomes of single-incision versus multi-port laparoscopic surgery for descending colon cancer: a propensity score-matched analysis.

BACKGROUND: The clinical impact of single-incision laparoscopic surgery (SILS) for descending colon cancer (DCC) is unclear. The aim of this study was to evaluate the clinical outcomes of SILS for DCC compared with multi-port laparoscopic surgery (MPLS). METHODS: We retrospectively analyzed 137 consecutive patients with stage I-III DCC who underwent SILS or MPLS at two high-volume multidisciplinary tertiary hospitals between April 2008 and December 2018, using propensity score-matched analysis. RESULTS: After propensity score-matching, we enrolled 88 patients (n = 44 in each group). SILS was successful in 97.7% of the matched cohort. Compared with the MPLS group, the SILS group showed significantly less blood loss and a greater number of harvested lymph nodes. Morbidity rates were similar between groups. Recurrence pattern did not differ between groups. No significant differences were found between groups in terms of 3-year disease-free and overall survivals. CONCLUSION: SILS appears safe and feasible and can provide satisfactory oncological outcomes for patients with DCC.

Evaluation of nephrotoxicity and ototoxicity following amikacin administration once daily or every 48 hours in neonates.

The purpose of this study was to evaluate the effects of once daily (OD) or every 48 hours (every-48-h) administration of amikacin (AMK) on renal function and ototoxicity in neonates. We investigated the frequency of nephrotoxicity and ototoxicity in neonates who received AMK OD or every-48-h from April 2015 to March 2021 and underwent dose evaluation by therapeutic drug monitoring (TDM). In addition, the relationships among birth weight, gestational age, AMK peak and trough values, total duration of AMK administration, and total AMK dose were examined separately for nephrotoxicity and ototoxicity. AMK was administered OD in 38 patients and every-48-h in 62 patients. Nephrotoxicity was observed in 8 patients on OD versus 36 patients on every-48-h administration (P < .001), and ototoxicity was observed in 2 patients on OD versus 12 patients on every-48-h administration (P = .192). For nephrotoxicity, only the trough value was relevant (P = .007). In terms of ototoxicity, there were no influencing factors. The risk of nephrotoxicity was higher with every-48-h AMK administration than with OD AMK administration, with nephrotoxicity depending on the trough value. However, compared with OD, the every-48-h group had lower body weight and possibly poorer original renal function. In addition, ototoxicity did not differ by administration method. Based on these results, every-48-h administration of AMK can be used as safely as OD by performing TDM and preventing high concentrations.

Volvulus of the stomach and wandering spleen after repair of congenital diaphragmatic hernia: unexpected manifestations in a neonate.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is sometimes associated with complications involving herniation of intrathoracic organs, which further increase mortality rate. We encountered a case of postoperative gastric and splenic volvulus shortly after left CDH repair in a female neonate who was treated with gastropexy. CASE PRESENTATION: At 39 weeks gestation, a female patient with left Bochdalek CDH was delivered (birth weight: 3748 g, Apgar score: 3/4). The patient was provided ventilator support with nitric oxide. After pulmonary hypertension improved, CDH repair was performed via the abdominal approach on day 7. The stomach, small intestine, large intestine, and spleen were herniated through a diaphragmatic defect of 4 × 2 cm. Although the diaphragm was directly closed, it was tight and the reconstructed diaphragm "dome" was shallow, restricting space for the spleen and stomach. Nonetheless, the spleen was positioned in the left upper abdomen and the stomach was positioned medially. The postoperative course was complicated by organo-axial gastric volvulus, and laparotomy was performed on day 14. In addition to the gastric volvulus, we confirmed a wandering splenic volvulus. The spleen was easily detorted and returned to the left upper abdomen. However, the patient experienced relapse of gastric volvulus without splenic volvulus. Gastropexy was performed electively on day 47. Postoperatively, the patient could be fed orally, and the patient's development was satisfactory 6 years after surgery. CONCLUSIONS: The cause of these rare complications appeared to be tight direct diaphragmatic closure, which reduced space for the spleen and stomach beneath the left diaphragm.

Comparison of clinical outcomes of single-incision versus multi-port laparoscopic surgery for rectosigmoid or upper rectal cancer.

BACKGROUND: Single-incision laparoscopic surgery (SILS) for rectal cancer is technically challenging, and its clinical impact is unclear. The aim of this study was to evaluate clinical outcomes of SILS for rectal cancer compared with multi-port laparoscopic surgery (MPLS). PATIENTS AND METHODS: We retrospectively analyzed 357 consecutive patients with stage I-III rectal cancer located in the rectosigmoid or upper rectum who underwent SILS or MPLS between January 2012 and December 2016, using propensity score-matched analysis. RESULTS: After propensity score-matching, we enrolled 204 patients (n = 102 per group). Before matching, significant group-dependent differences were observed in tumor location (p < 0.001). After matching, preoperative clinical factors were similar between groups. SILS was successful in 73.5% of cases, an additional port was required in 23.5%, and 2.9% were converted to open surgery. Compared to the MPLS group, the SILS group showed shorter operative time (192 vs. 211 min, p = 0.015) and shorter postoperative hospital stay (9 vs. 11 days, p = 0.038). Other operative factors and morbidity rates did not differ significantly between groups. The number of harvested lymph nodes was smaller in the SILS group (24) than in the MPLS group (27, p = 0.008). Postoperative recurrence did not differ between groups, either before or after matching. No significant differences in 3-year disease-free, 3-year local recurrence-free, or 5-year overall survival were found between groups. CONCLUSIONS: SILS is safe, is feasible, and offers satisfactory oncological outcomes in selected patients with rectosigmoid or upper rectal cancer.

Single-Incision Laparoscopic Cholecystectomy: a Single-Centre Experience of 1469 Cases.

BACKGROUND: Despite having once been extensively used for cosmetics or pain reduction, the use of single-incision laparoscopic cholecystectomy (SILC) has declined in recent years due to technical difficulties and a reported increase in complications. Since the introduction of SILC in 2009, our hospital has been actively involved with this technique. Our experience suggests that SILC is not a difficult procedure and can be safe and useful, with particularly excellent cosmetic outcomes. This study retrospectively details the outcomes of SILC at our hospital. METHOD: Data on 1469 cases of SILC performed on a waitlist basis at Osaka Police Hospital from May 2009 to December 2020 were collected and retrospectively analysed. RESULTS: The median operative time and blood loss were 96 min and 0 mL, respectively. A total of 46 patients (3.1%) required conversion surgery, including 36 needing additional ports and 10 requiring laparotomy. Intraoperative complications included common bile duct injury in 1 patient (0.07%) and right hepatic artery injury in 1 patient (0.07%), with no other organ injury. Postoperative Clavien-Dindo 3 or higher complications were observed in 18 patients (1.2%). Incisional hernias occurred in 15 patients (1.0%). The median postoperative hospital stay was 3 days. CONCLUSION: This study showed that SILC can be performed safely without any increase in complications, as reported previously. Granted that it is performed safely, SILC may be a useful technique due to its superior cosmetic outcomes or pain reduction.

Laparoscopic mesh removal for mesh infection related to pararectal incision of previous appendectomy after laparoscopic total extraperitoneal inguinal hernia repair: A case report.

A 67-year-old man with a history of appendectomy 40 years ago underwent single-incision laparoscopic surgery for total extraperitoneal inguinal hernia repair. Postoperatively, the pararectal incisional scar obtained from the appendectomy was infected; thus, antibiotic therapy and drainage were performed. However, the infection persisted. After 5 postoperative months, the mesh was laparoscopically removed at a sufficient distance from the infected site. No enterocutaneous fistula was observed. After 1 year and 10 months, no recurrence of hernia or infection was observed. Thus, laparoscopic mesh removal is feasible. Infection of a 40-year-old incision rarely results in mesh infection. Therefore, in pararectal incision, the extent of mesh coverage should be considered; if the overlap is large, changing the technique by not covering the incision may be necessary.

Long-term outcomes of single-incision versus multiport laparoscopic colectomy for colon cancer: results of a propensity score-based analysis.

BACKGROUND: Long-term outcomes of single-incision laparoscopic colectomy (SILC) for colon cancer (CC), as practiced in real-world settings, especially in relation to disease stage, have not been established. We examined, retrospectively, both short- and long-term outcomes of SILC versus those of multiport laparoscopic colectomy (MPLC) performed for CC in a propensity-score-matched cohort. METHODS: The study involved 263 patient pairs matched 1:1 from among 691 patients who, between January 2008 and May 2014, underwent either SILC or MPLC for a primary solitary CC at our hospital. Short-term and long-term operative outcomes were compared between the two groups. RESULTS: Operation time was the only surgical outcome that varied significantly between the two groups (p = 0.0004). Overall 5-year cancer-specific survival (CSS) in the SILC group was 93.7 (95% CI 89.6-96.2)%, and CSS per pathological stage (I, II and III) was 98.5 (90.0-99.8)%, 96.0 (88.2-98.7)%, and 88.3 (79.6-93.6)%, respectively, whereas overall 5-year CSS in the MPLC group was 93.3 (89.4-95.9)%, and CSS per pathological stage was 100%, 95.4 (88.3-98.3)%, and 84.1 (74.1-90.8)% (p = 0.5278, 0.2679, 0.7666, and 0.9073), respectively. Overall 3-year disease-free survival (DFS) in the SILC group was 94.0 (90.2-96.4)%, and 3-year DFS per pathological stage was 98.6 (90.4-99.8)%, 90.1 (81.4-95.0)%, and 79.0 (69.4-86.2)%, respectively, whereas overall 3-year DFS in the MPLC group was 93.2 (89.4-95.7)%, and 3-year DFS per pathological disease stage was 100%, 94.5 (87.4-97.7)% and 75.5 (64.7-83.8)% (p = 0.2829, 0.7401, 0.4335 and 0.8518), respectively. Thus, oncological outcomes did not differ significantly between groups. Incisional hernia occurred in 21 (8.0%) SILC group patients and 17 (6.5%) MPLC group patients, without a significant between-group difference (p = 0.6139). CONCLUSION: Our data indicate that perioperative and oncological outcomes of SILC performed for CC are comparable to those of MPLC performed for CC.

Short- and Long-Term Outcomes of Single-Incision Laparoscopic Surgery for Right-Side Colon Cancer.

INTRODUCTION: There are little data concerning the long-term outcome of single-incision laparoscopic surgery (SILS) for colon cancer. Therefore, we investigated not only the short-term outcomes but also the long-term outcomes of SILS for right-side colon cancer. METHODS: We retrospectively compared short- and long-term outcomes of SILS and conventional laparoscopic surgery (CLS) for right-sided colon cancer in our institution. Intergroup differences of short-term outcomes were evaluated using χ2 or Fisher exact tests and 2-sample Student t tests. The disease-free survival rates (long-term outcome) of stage II and III patients were estimated using the Kaplan-Meier method and compared using log-rank tests. RESULTS: There were 290 operations conducted for right-side (cecum and ascending) colorectal cancers from April 2011 to July 2018. Open surgery was performed in 12 cases from start to the operation. SILS was performed in 196 cases and CLS in 55 cases. One patient underwent intraoperative conversion from SILS to laparotomy for bleeding control. In addition, 1 port was added to SILS in 3 cases. These 4 cases were included in the analysis as the SILS group according to the principle of intent to treat. BACKGROUND: Factors including age, gender, body mass index, performance status, and tumor stage were not statistically different between the SILS and CLS groups. In short-term outcomes, the number of harvested lymph nodes was not statistically different. SILS required less operating time (p < 0.001) and resulted in a reduced bleeding volume (p < 0.001). There was no statistical difference in the frequency of overall complications (p = 0.06). The disease-free survival of stage II and III patients was not statistically different between the 2 groups. CONCLUSIONS: With the proper adaptation of SILS by an experienced surgeon, the short- and long-term outcomes of SILS were not inferior to those of CLS. Therefore, SILS could be a treatment option for right-sided colon cancer.

Index for the appropriate vancomycin dosing in premature neonates and infants.

BACKGROUND: In neonates, vancomycin (VCM) is used to treat Gram-positive bacterial infections. However, VCM blood concentrations are affected by gestational age, bodyweight (BW), and renal function. The initial VCM dose adjustment can therefore be difficult, and few reports have evaluated this issue. In this study, we investigated the factors determining the appropriate VCM dosing schedule in neonates, especially premature infants. METHODS: The VCM dosage and trough concentrations were retrospectively investigated from the initial treatment to maintenance therapy in neonatal intensive care unit patients who underwent therapeutic drug monitoring. We examined the average single-administration VCM dosage during maintenance therapy. We then compared the actual VCM dose with that calculated using an index comprising six items that influence the VCM daily dose (postnatal age, gestational age, BW, serum creatinine level, urine output, and lactate level). RESULTS: Twenty premature infants were included. The average BW of patients at the initial VCM administration was 975 g. During maintenance therapy, the average VCM dose was 8.4 mg/kg, and the median trough concentration was 12.4 µg/mL. When we applied the six-item index, 18 of 20 patients (90%) had concordant results between the actual VCM dosing schedule and the VCM calculated using the index. CONCLUSIONS: The average VCM dose and six-item index can facilitate the transition from the initial VCM dose to an appropriate dose in many cases and contribute to early treatment in low-birthweight infants with more variable BW, distribution volumes, and renal function. In conclusion, our six-item index may help standardize VCM administration in premature infants.