Masakazu Tokunaga

Single-port laparoscopic colectomy versus conventional laparoscopic colectomy for colon cancer: a comparison of surgical results

BackgroundSingle-port laparoscopic surgery is a new technique that leaves no visible scar. This new technique has generated strong interest among surgeons worldwide. However, single-port laparoscopic colon surgery has not yet been standardized. Our aim in this study was to evaluate the feasibility of single-port laparoscopic colectomy compared with conventional laparoscopic colectomy for colon cancer.MethodsWe conducted a case-matched, controlled study comparing single-port laparoscopic colectomy to conventional laparoscopic colectomy for right-sided colon cancer.ResultsA total of ten patients were included for the single-port laparoscopic colectomy (S-LAC) group and ten patients for the conventional laparoscopic colectomy (C-LAC) group. The length of the skin incision in the S-LAC group was significantly shorter than that of the C-LAC group.ConclusionOur early experiences indicated that S-LAC for right-sided colon cancer is a feasible and safe procedure and that S-LAC results in a better cosmetic outcome.

Scientific assessment of endoscopic surgical skills.

Abstract Recently, significant attention has been focused on training and education for safe endoscopic surgery. A new assessment method, the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD), has been designed at Hiroshima University to evaluate the smoothness of the movement of endoscopic instruments from velocity. Experts (with experience in performing more than 100 laparoscopic surgeries) and novices (with no experience in performing laparoscopic surgery) were recruited for this study. The aim of task 1 was to move the tip of the endoscopic instrument on the tops of poles from A to C, and task 2 was to move it from the right pole B to the left pole D. The peak velocity (Vp) and the time when peak velocity appears (Tp) were analyzed. Both the peak velocity (Vp) and the time when peak velocity appears (Tp) to perform task 1 and task 2 were significantly faster in the expert group than in the novice group. The peak velocity (Vp) and the time when peak velocity appears (Tp) in HUESAD, which indicate the smoothnes of the endoscopic procedure, are among the most important factors for assessing endoscopic surgical skills.

Primary lung cancer presenting with metastasis to the colon: a case report

Although about 50% of lung cancers have distant metastasis at the time of initial diagnosis, colonic metastases are extremely rare. This report presents a rare clinical case of colonic metastasis from primary squamous cell carcinoma of the lung.A 60-year-old female with anorexia and fatigue was referred to the department of pulmonary surgery in our hospital. The patient was diagnosed with primary squamous cell carcinoma of the lung, T2b N3 M1b Stage IV, and chemoradiotherapy was initiated. This treatment led to a good partial response in the primary lung lesion without any new metastatic lesions.The patient developed left abdominal pain due to a bulky sigmoid colon tumor 6 months later, and was preoperatively diagnosed with primary colon cancer. She underwent colonic resection, and the pathology specimen demonstrated poorly differentiated squamous cell carcinoma that was suspected to be colonic metastasis from the primary lung cancer. The postoperative course was uneventful, and she was discharged. Chemotherapy for the lung cancer was scheduled in the department of pulmonary surgery.This report presented a rare case of colonic metastasis from lung cancer. When patients with advanced primary lung cancer complain of abdominal symptoms, we should consider gastrointestinal tract metastasis from lung cancer.

Retroperitoneal abscess complicated with necrotizing fasciitis of the thigh in a patient with sigmoid colon cancer

BackgroundNecrotizing fasciitis of the thigh due to the colon cancer, especially during chemotherepy, has not been previously reported.Case presentationA 67-year-old man admitted to the hospital was diagnosed with sigmoid colon cancer that had spread to the left psoas muscle. Multiple hepatic metastases were also found, and combination chemotherapy with irinotecan and S-1 was administered. Four months after the initiation of chemotherapy, the patient developed gait disturbance and high fever and was therefore admitted to the emergency department of our hospital. Blood examination revealed generalized inflammation with a high C-reactive protein level. Computed tomography of the abdomen and pelvis showed gas and fluid collection in the retroperitoneum adjacent to the sigmoid colon cancer. The abscess was locally drained under computed tomographic guidance; however, the infection continued to spread and necrotizing fasciitis developed. Consequently, emergent debridement was performed. The patient recovered well, and the primary tumor was resected after remission of the local inflammation.ConclusionNecrotizing fasciitis of the thigh due to the spread of sigmoid colon cancer is unusual, but this fatal complication should be considered during chemotherapy for patients with unresectable colorectal cancer.

Preservation of peritoneal fibrinolysis owing to decreased transcription of plasminogen activator inhibitor-1 in peritoneal mesothelial cells suppresses postoperative adhesion formation in laparoscopic surgery

BACKGROUND Postoperative adhesion formation is regulated by peritoneal fibrinolysis, which is determined by tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). This study compared peritoneal fibrinolysis and adhesion formation after laparoscopic surgery (LAP) and open surgery (OP). METHODS We divided 154 male rats into 3 groups after cecal cauterization: Control, no treatment; LAP, CO2 pneumoperitoneum at 5 mmHg for 60 minutes; and OP, laparotomy for 60 minutes. Adhesions were quantified at day 7. The activity and mRNA level of tPA and PAI-1 were determined by enzyme-linked immunosorbent assay in plasma and peritoneal lavage and by real-time polymerase chain reaction in peritoneal mesothelial cells from omentum. We also examined peritoneal fibrinolysis in human gastric cancer patients treated with LAP (n = 14) or OP (n = 10). RESULTS In the animal study, adhesion scores, PAI-1 activity in peritoneal lavage fluid, and PAI-1 mRNA levels in peritoneal mesothelium were significantly greater in the OP group than the control and LAP groups. In the human study, postoperative PAI-1 mRNA levels were significantly greater in the OP group than the LAP group. Additionally, PAI-1 mRNA levels and subsequent adhesion formation were induced by prolonged operative time in the OP group, but not the LAP group. CONCLUSION Preservation of peritoneal fibrinolysis owing to decreased PAI-1 expression at the transcriptional level in peritoneal mesothelial cells is associated with suppression of postoperative adhesion formation in LAP. PAI-1 mRNA levels and subsequent adhesion formation were not induced by prolonged operative time in LAP. These results highlight the less invasiveness nature of LAP.

Approaching time is important for assessment of endoscopic surgical skills

Abstract This study aimed to verify whether the approaching time (the time taken to reach the target point from another point, a short distance apart, during point-to-point movement in endoscopic surgery), assessed using the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD), could distinguish the skill level of surgeons. Expert surgeons (who had performed more than 50 endoscopic surgeries) and novice surgeons (who had no experience in performing endoscopic surgery) were tested using the HUESAD. The approaching time, total time, and intermediate time (total time – approaching time) were measured and analyzed using the trajectory of the tip of the instrument. The approaching time and total time were significantly shorter in the expert group than in the novice group (p < 0.0001). The intermediate time did not significantly differ between the groups (p > 0.05). The approaching time, which is a component of the total time, is very mportant in the measurement of the total time to assess endoscopic surgical skills. Further, the approaching time was useful for skill assessment by the HUESAD for evaluating the skill of surgeons performing endoscopic surgery.

Adequate lymph node examination is essential to ensure the prognostic value of the lymph node ratio in patients with stage III colorectal cancer

PurposeThis study aimed to assess the prognostic value of the lymph node ratio (LNR), estimated by dividing the number of positive lymph nodes (LNs) by the number of LNs examined, for stage III colorectal cancer in comparison to the new tumor, nodes, and metastasis (TNM) system, and to evaluate the relationship between the number of LNs examined and the prognostic value of the LNR.MethodsWe retrospectively reviewed the clinicopathological data of a cohort of 266 patients with stage III colorectal cancer. We assessed the impact of LNR on the prediction of cancer recurrence in comparison to the TNM system, as well as the prognostic value of LNR in patients with a low LN count.ResultsIn multivariate analysis, the LNR was found to be an independent risk factor of cancer recurrence. The application of the LNR, in addition to the new TNM system, was more predictive of survival than the TNM system alone. A prognostic separation by LNR was observed in patients who had an adequate number of LNs examined, but not in patients with a low LN count.ConclusionsA stronger prognostic separation can be obtained by using the LNR together with the new TNM system. Adequate lymph node examination is important to ensure the prognostic value of LNR in patients with stage III colorectal cancer.

The Importance of Stressing the Use of Laparoscopic Instruments in the Initial Training for Laparoscopic Surgery Using Box Trainers: A Randomized Control Study

BACKGROUND The goal of this study was to improve the efficiency of initial box training for laparoscopic surgery. MATERIALS AND METHODS The study used the following task: suturing and knot tying task under a combination of four conditions. (1) The C (use of conventional instruments)-D (direct vision); (2) the C-V (indirect vision via a video monitor); (3) the L (use of laparoscopic instruments)-D; and (4) the L-V (the standard laparoscopic suturing and knot tying). The first study assessed 11 medical students undergoing L-V training. The time to complete each of the four assessment tasks was recorded pre- and post-training. The second study was a randomized, controlled trial involving 36 students grouped according to three types of training methods: the L-D, the C-V, and the L-V group. The improvement in the time to complete the L-V task was assessed and the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD) was used for assessment as well. RESULTS In the first study, a significant improvement in the performance time between pre- and post-training for the L-D task was found, but not for the C-V task. The second study found that the improvement rate of the L-D trained group was significantly greater than that of the C-V and L-V groups. The HUESAD assessment also showed the similar results. CONCLUSIONS A training program stressing the use of laparoscopic instruments and compensating for the fulcrum effect is more effective for novices using box trainers in the initial laparoscopic surgery instruction than one emphasizing performing the tasks via a video monitor.

Evaluating the correlation between the HUESAD and OSATS scores: Concurrent validity study

Abstract Background: The aim of this study was to determine whether a correlation exists between the HUESAD and both the OSATS checklist and the global rating score. Material and methods: Fourteen participants were recruited, ranging from residents to consultants. The HUESAD measured three different parameters: Visual spatial ability, smoothness and accuracy. The OSTAS measured the endoscopic surgical skills by the checklist and the global rating score. Results: A significant relationship was thus identified between the OSATS checklist (p < 0.0001), the OSATS global rating score (p < 0.05) and the HUESAD assessment in the evaluation of visual-spatial ability. In terms of smoothness, there was also a significant relationship between the OSATS checklist (p < 0.05), the OSATS global rating score (p < 0.05) and the HUESAD assessment. Moreover, there was a significant relationship between the OSATS checklist (p < 0.05), the OSATS global rating score (p < 0.05) and the HUESAD assessment for accuracy. Conclusions: There was strong correlation between the motion analysis in the HUESAD assessment and OSATS checklist and the global rating score. Moreover, the visual spatial ability, smoothness and accuracy analyzed by the HUESAD were reliable parameters when assessing the endoscopic surgical skills.

Malignant peripheral nerve sheath tumor arising from the greater omentum: Case report

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue tumors that arise from a peripheral nerve or exhibit nerve sheath differentiation. Most of these tumors arise on the trunk, extremities, or head and neck regions; they are very rarely located in the abdominal cavity. The patient was a 71-year-old man who was referred to our hospital for a mass and pain in the right lower abdomen. Abdominal computed tomography revealed a large (9 × 9 cm), well-circumscribed, lobulated, heterogeneously enhanced mass in the pelvis. Exploratory laparotomy revealed a large mass in the greater omentum, and the tumor was completely excised. Histopathological analysis revealed that the tumor was composed of spindle cells with high mitotic activity. On staining the tumor, positive results were obtained for S-100 but negative results were obtained for c-kit, cluster of differentiation (CD)34, α-smooth muscle actin, and desmin. These findings strongly supported a diagnosis of MPNST primarily arising from the greater omentum. To the best of our knowledge, this is the first reported case of an MPNST arising from the greater omentum. In this report, we have described the case of a patient with an MPNST arising from the greater omentum and have discussed the clinical characteristics and management of MPNSTs.