Effects of rod stiffness and fusion mass on the adjacent segments after floating mono-segmental fusion: a study using finite element analysis

Purpose

The aims of the present study were to compare the biomechanical effects on the adjacent segments after mono-segmental floating fusion with posterior semi-rigid or rigid stabilization, and to evaluate the effect of the amount of fusion mass on the biomechanical differences.

Methods

A detailed, nonlinear L1–S1 finite element model had been developed and validated. Then five models were reconstructed by different fixation techniques on the L3–L4 level: rigid fixation with an interbody spacer (Ti + IS), rigid fixation with a large interbody spacer (Ti + IS_all), semi-rigid fixation with an interbody spacer (PEEK + IS), semi-rigid fixation with a large interbody spacer (PEEK + IS_all), and semi-rigid fixation only (PEEK). Analyses were conducted for the case of erect standing position, flexion, and extension motion.

Results

At L1–L2 and L2–L3, PEEK + IS demonstrated less inter-segmental rotation and nucleus pressure increments from the intact model compared with Ti + IS. The L4–L5 and L5–S1 levels showed slightly higher values with PEEK + IS, but these differences among the instrumented models were not significant. The motion difference based on the fusion mass at the adjacent levels was at most 3 %. All instrumentation cases generated a 55 % higher facet contact force at the lower adjacent level (L4–L5) compared to that of the intact model during 26° extension and the largest increment was detected at the upper adjacent level (L2–L3) in the Ti + IS. Instrumentation with Ti + IS markedly increased the stress in the intervertebral disk at the upper adjacent level, while the stress with PEEK + IS appeared largest at the lower adjacent level.

Conclusions

Posterior instrumentation with semi-rigid rods may lower the incidence of disk and facet degeneration in the upper adjacent segment compared to rigid rods. On the other hand, the possibility of facet degeneration will be similar for all instrumentation devices in the lower adjacent segment in the long-term. The stiffness difference between rigid and semi-rigid rods on the changes in the adjacent motion segments was more crucial than amount of fusion mass.     

Internal plug mesh without fixation in laparoscopic total extraperitoneal (TEP) repair of inguinal hernias: a pilot study

Purpose

Mesh fixation is essential in laparoscopic total extraperitoneal (TEP) repair of inguinal hernia; however, fixation sometimes causes post-operative pain. This study investigated a novel method of laparoscopic TEP repair without mesh fixation.

Methods

This study reviewed data from about two-hundred and forty-one laparoscopic TEP repairs on 219 patients, which were performed between December 2004 and October 2005.

Results

There were no statistically significant differences in the recurrence rate, seroma formation, and hospital stay. However, the mean operation time was shorter in the internal plug mesh group than the fixation group (p = 0.009), and post-operative pain only occurred in 4 cases in the internal plug mesh group in comparison to 29 cases in the mesh fixation group (p = 0.014).

Conclusions

An internal plug mesh without fixation might reduce post-operative pain after laparoscopic TEP repair of an inguinal hernia. Internal plug mesh without fixation may be an alternative method in laparoscopic TEP repair, especially for those involving indirect hernias.     

Intra‐operative cardiac arrests during liver transplantation – a retrospective review of the first 15 yr in Asian population

Although many report intra‐operative cardiac arrests (ICAs) in liver transplantation (LT), the incidence, major causes, and outcome remain unclear. We aimed to investigate retrospectively, the incidence, nature, and outcome of ICA in Asian population and to identify risk factors for ICA. Consecutive 1071 LTs in an institution during 1996–2011 (adult 920, pediatric 151/living donor liver transplantation, LDLT 841, deceased donor liver transplantation, DDLT 230) were reviewed. ICA occurred in 14 adult LTs (1.5%), but none in pediatrics. ICA occurred 1.0% and 3.3% in LDLT and DDLT, respectively. Stages of ICA incidence were three at pre‐anhepatic, one at anhepatic, and 10 at neohepatic stage. Post‐reperfusion syndrome (PRS) with hyperkalemia and bleeding were the major causes of ICA. While LDLT showed miscellaneous causes for ICA at various stages, DDLT incurred ICAs at neohepatic stage only. Interestingly, we did not find pulmonary thromboembolism (PTE) to incur ICA. Risk factor analysis showed no association of pre‐operative patient condition, donor types, and intra‐operative parameters. In this review, the incidence of ICA was low in Asian population with LDLT predominance, and while PTE was not the cause of ICA, the neohepatic stage with PRS and bleeding was the most vulnerable period to anticipate ICA.     

Role of Cholecystectomy and Lymph Node Dissection in Patients with T2 Gallbladder Cancer

Background

Incidental findings of gallbladder cancer (GBCA) have dramatically increased as an initial presentation of the disease because of the expansion of laparoscopic cholecystectomy. However, the optimal management of T2 GBCA remains at issue.

Methods

We compared our 10-year experience with the consensus surgical strategy for T2 GBCA. Between January 2000 and December 2009, 70 patients at Severance Hospital, Yonsei University Health System, Seoul, Korea, underwent surgical treatment for GBCA stage T2. The medical records of 70 patients with T2 GBCA were retrospectively reviewed.

Results

Radical cholecystectomy was performed on only 32 (45.8 %) patients. In patients with T2 GBCA and positive lymph nodes (LN), the overall survival rate between cholecystectomy with LN dissection and radical cholecystectomy did not show a significant difference. Twenty patients experienced recurrence during the follow-up period. Among the 11 patients who underwent cholecystectomy with liver resection, only 2 (18.2 %) patients had an intrahepatic recurrence. Of the 9 patients who underwent cholecystectomy without liver resection, 3 (33.3 %) patients had an intrahepatic recurrence. However, recurrences at the gallbladder bed occurred only in one and two patients, respectively, and were not significantly different between the two groups.

Conclusions

There was a large gap between clinical practice and treatment guidelines. Though relatively few patients enrolled in this study experienced recurrence, cholecystectomy and LN dissection without liver resection showed similar survival and recurrence patterns compared with those of radical cholecystectomy. To improve consistency between clinical practice and consensus guidelines, the role of limited resection for T2 lesions needs further evaluation.     

Argon plasma coagulation is safe and effective for treating smaller gastric lesions with low-grade dysplasia: a comparison with endoscopic submucosal dissection

Background and aims

The best therapeutic modality has not been established for gastric low-grade adenomas or dysplasia (LGD), which can progress to invasive carcinoma despite a low risk. This study aims to investigate the clinical efficacy, safety, and local recurrence after argon plasma coagulation (APC) treatment of gastric LGD compared with endoscopic submucosal dissection (ESD).

Patients and methods

A total of 320 patients with gastric LGD ≤2.0 cm treated with APC or ESD between 2004 and 2011 were retrospectively analyzed. We compared local recurrence rate, complication rate, procedure time, and admission to hospital between APC and ESD groups.

Results

Of the 320 patients, 116 patients were treated with APC and 204 with ESD. During follow-up, local recurrence was more common in the APC group (3.8 %, 4/106) than the ESD group (0.5 %, 1/188; log-rank test P = 0.036). However, all patients with local recurrence (n = 5) were treated by additional APC, and followed up without further recurrences. ESD was complicated by two perforations (1.0 %, 2/204) compared with no perforations in the APC group (0 %, 0/116). Bleeding complications were not different between the APC (1.7 %, 2/116) and ESD (2.0 %, 4/204) groups. Procedure time was shorter in the APC (7.8 ± 5.1 min) than the ESD (53.1 ± 38.1 min) group (P < 0.001). The proportion of hospitalization was less in the APC group (31.0 %, 36/116) than the ESD group (100.0 %, 204/204) (P < 0.001).

Conclusions

APC can be a good treatment option for patients with LGD ≤2.0 cm.     

Proper preparation to reduce endoscopic reexamination due to food residue after distal gastrectomy for gastric cancer

Background

Reducing food residue by proper preparation methods before endoscopy after distal gastrectomy can increase the quality of examination and decrease patient discomfort. We evaluated the risk factors for food residue and proper methods of preparation for endoscopy after distal gastrectomy.

Methods

Follow-up endoscopy with questionnaires was performed on 1,001 patients who underwent distal gastrectomy at Asan Medical Center between December 2010 and July 2011.

Results

Endoscopic examination failed in 94 patients (9.4 %) as a result of large amounts of food residue. Rates of failure were significantly higher in patients who ate a regular diet rather than a soft diet at last dinner before examination (13.9 vs. 6.1 %, p = 0.050), and in those who ate lunch rather than not eating lunch on the day before examination (14.6 vs. 7.7 %, p = 0.020). Multivariate analysis showed that the rate of failed examination was lower in patients who had a history of abdominal surgery (p = 0.011), those who ate a soft (p < 0.001) or liquid (p = 0.003) diet as a last meal rather than a regular diet, those who underwent Billroth I rather than Billroth II reconstruction (p = 0.035), patients with longer fasting time (p = 0.009), and those with a longer gastrectomy-to-endoscopy time interval (p < 0.001).

Conclusions

Patients who undergo follow-up endoscopy after surgery should fast more than 18 h and ingest a soft or liquid diet on the day before examination.     

ERCP via gastrostomy vs. double balloon enteroscopy in patients with prior bariatric Roux-en-Y gastric bypass surgery

Background

Roux-en-Y gastric bypass (RYGB) is the most common bariatric surgery. The performance of ERCP in bariatric RYGB is challenging due to the long Roux limb. We herein compared the indications and technical outcomes of ERCP via percutaneous gastrostomy (GERCP) and double balloon enteroscopy (DBERCP) for patients with prior bariatric RYGB anatomy.

Methods

Between December 2005 and November 2011, consecutive ERCP patients who had undergone RYGB were identified using a prospectively maintained electronic ERCP database. Medical records were abstracted for ERCP indications and outcomes. In most cases, the gastrostomy was done by either laparoscopic or open surgery and allowed to mature at least 1 month before performing ERCP. The choice of route for ERCP was at discretion of managing physician.

Results

Forty-four patients (F = 42) with GERCP and 28 patients (F = 26) with DBERCP were identified. The mean age was younger in GERCP than DBERCP (44.8 vs. 56.1, p < 0.001). GERCP patients were more likely to have suspected sphincter of Oddi dysfunction (77 %) as the primary indication whereas DBERCP was suspected CBD stone (57 %). The mean total number of sessions/patient in GERCP and DBERCP was 1.7 ± 1.0 and 1.1 ± 0.4, respectively (p = 0.004). GERCP access to the major papilla was successful in all but two (97 %), whereas duct cannulation and interventions were successful in all. In DBERCP, the success rate of accessing major papilla, cannulation and therapeutic intervention was 78, 63, 56 %, respectively. There was one (3.1 %) post-ERCP pancreatitis in DBERCP. Complications occurred in 11 GERCP procedures (14.5 %) and 10 were related to the gastrostomy. This was significantly higher than that of DBERCP (p = 0.022).

Conclusions

GERCP is more effective than DBERCP in gaining access to the pancreatobiliary tree in patients with RYGB, but it is hindered by the gastrostomy maturation delay and a higher morbidity. Technical improvements in each method are needed.     

Blurry Boundaries: Do Epithelial Borderline Lesions of the Breast and Ductal Carcinoma In Situ Have Similar Rates of Subsequent Invasive Cancer?

Background

The histology of epithelial “borderline lesions” of the breast, which have features in between atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS), is well described, but the clinical behavior is not. This study reports subsequent ipsilateral breast events (IBE) in patients with borderline lesions compared with those with DCIS.

Methods

Patients undergoing breast-conserving surgery for borderline lesions or DCIS from 1997 to 2010 were identified from a prospective database. IBE was defined as the diagnosis of subsequent ipsilateral DCIS or invasive ductal carcinoma.

Results

A total of 143 borderline-lesion patients and 2,328 DCIS patients were identified. Median follow-up was 2.9 and 4.4 years, respectively. 7 borderline-lesion and 172 DCIS patients experienced an IBE. 5 year IBE rates were 7.7 % for borderline lesions and 7.2 % for DCIS (p = .80). 5 year invasive IBE rates were 6.5 and 2.8 %, respectively (p = .25). Similarly, when analyses were restricted to patients who did not receive radiotherapy, or endocrine therapy, or both, borderline-lesion and DCIS patients did not demonstrate statistically significant differences in rates of IBE or invasive IBE.

Conclusions

When compared with DCIS, borderline lesions do not demonstrate lower rates of IBE or invasive IBE. Despite “borderline” histology, a 5 year IBE rate of 7.7 % and an invasive IBE rate of 6.5 % suggest that the risk of future carcinoma is significant and similar to that of DCIS.