Function of mechanically lengthened jejunum after restoration into continuity

Purpose

Distraction enterogenesis is a potential treatment for patients with short bowel syndrome. We previously demonstrated successful lengthening of jejunum using a degradable spring device in rats. Absorptive function of the lengthened jejunum after restoration into intestinal continuity needs to be determined.

Methods

Encapsulated polycaprolactone springs were placed into isolated jejunal segments in rats for four weeks. Lengthened segments of jejunum were subsequently restored into intestinal continuity. Absorption studies were performed by placing a mixture of a non-absorbable substrate and glucose into the lumen of the restored jejunum.

Results

Restored jejunal segments demonstrated visible peristalsis at specimen retrieval. Compared to normal jejunal controls, restored segments demonstrated equal water absorption and greater glucose absorption. Restored segments had thicker smooth muscle, increased villus height, increased crypt depth, and decreased sucrase activity compared to normal jejunum. The density of enteric ganglia increased after restoration to near normal levels in the submucosa and to normal levels in the myenteric plexus.

Conclusion

Jejunum lengthened with a degradable device demonstrates peristaltic and enzymatic activity as well as glucose and water absorption after restoration into intestinal continuity. Our findings further demonstrate the therapeutic potential of a degradable device.     

The feasibility of using an endoluminal device for intestinal lengthening

Purpose

Prior studies demonstrating the ability to lengthen intestinal segments with mechanical force required devices with extracorporeal components. The feasibility of using a completely implantable device for in vivo intestinal lengthening was evaluated in this study.

Methods

Biocompatible Nitinol springs capable of 5-fold expansions were compressed using absorbable sutures and were implanted into isolated segments of proximal jejunum in rats. Springs compressed with nonabsorbable sutures served as controls. The animals were observed with serial abdominal x-rays until the springs became fully expanded. Intestinal segments were then retrieved for histologic analysis. Two-tailed and paired Student's t tests were used for statistical analysis.

Results

Intestinal segments were successfully lengthened in the experimental group from 1.3 ± 0.3 cm to 4.4 ± 0.5 cm (P < .001). Maximum spring length was achieved on postoperative day 36 (range, 16-50 days). In the control group, there was also an increase in intestinal lengths, from 1.6 ± 0.04 cm to 2.9 ± 0.4 cm (P < .001) (Fig. 4). In percentages, a 250% increase in length was observed in the experimental group vs an 85% increase in the control group (P < .001). Microscopic evaluation of both control and experimental segments revealed gross preservation of intestinal architecture; however, muscular layer hypertrophy and villous atrophy were noted.

Conclusions

Continuous mechanical force with an implantable spring successfully lengthened isolated segments of small bowel in an animal model. Although similar results have been demonstrated using other devices, the current device is totally implantable and may be deployed endoscopically.     

Double plication for spring-mediated intestinal lengthening of a defunctionalized Roux limb

Background

Spring-mediated distraction enterogenesis has been shown to increase the length of an intestinal segment. The goal of this study is to use suture plication to confine a spring within an intestinal segment while maintaining luminal patency to the rest of the intestine.

Intestinal lengthening via multiple in-continuity springs

Background

Short bowel syndrome is a debilitating condition with few effective treatments. Spring-mediated distraction enterogenesis can be used to lengthen intestine. The purpose of this study is to determine whether multiple springs in series can safely increase the total amount of lengthening.

Sustainability of mechanically lengthened bowel in rats

Introduction

It has been shown that the length of an intestinal segment may be doubled by applying gradual mechanical stretching. This study evaluated whether the lengthened intestinal segment retained the structure and function after the stretching device was removed.

Methods

A 1.5-cm jejunal segment was separated from intestinal continuity in 20 rats. After advancing a screw into the isolated jejunal segment by 5 mm 3 times a week until it was stretched by 3 cm, the screw was removed. Three weeks later, the jejunal segments were retrieved for analyses. Comparisons were made between the lengthened jejunal segments.

Results

The jejunal segment doubled its length after gradual stretching and retained this length 3 weeks after the screw removal (3.1 ± 0.8 vs 3.2 ± 0.4 cm, P > .05). The villous height, the muscular thickness, and the total alkaline phosphatase and lactase activities of the stretched jejunal segments were also unchanged 3 weeks after the screw removal.

Conclusions

Mechanical force induced the sustained lengthening of isolated jejunal segments in rats. The histologic and enzymatic alterations also persisted 3 weeks after the mechanical force was removed. This phenomenon may provide a novel method for the treatment of short bowel syndrome.     

Spiral intestinal lengthening and tailoring — first in vivo study

Introduction

Spiral Intestinal Lengthening and Tailoring (SILT) offers a new opportunity for the surgical treatment of short bowel syndrome. SILT requires less manipulation on the mesentery than the Bianchi procedure and does not alter the orientation of the muscle fibers like serial transverse enteroplasty (STEP). This study reports the first SILT results in a surviving animal model.

Material and Methods

Vietnamese minipigs (n = 6) underwent interposition of a reversed intestinal segment to produce proximal small bowel dilation. Five weeks later the reversed segment was resected, and the wall of the dilated intestine was cut spirally at 45°–60° to its longitudinal axis. The bowel was lengthened longitudinally, and the spiral shaped intestinal wound was sutured. Five weeks later, the animals were explored, and the lengthened segments were measured. Haematoxylin and eosin, picrosirius, neuron specific enolase, S-100, C-kit, and immunohistochemistry were performed.

Results

Mean lengthening was 74.8% ± 29.5% and mean tailoring (lumen reduction) was 56.25% ± 18.8%. No instances of necrosis, perforation, suture break down, or peritonitis were observed in 6/6 animals. Four of six animals recovered uneventfully with viable lengthened segments. Statistical analysis showed no significant difference in length (p = 0,078) and width (p = 0,182) after 5 weeks. Two animals developed bowel obstruction due to narrowed lumen, adhesion, and strangulation after 14 and 24 days of surgery. In both animals the lumen was tailored by more than 70% to less than 1.5 cm diameter. The mucosa and the muscle layers in the operated segment had become hypertrophic, but the orientation of the circular and longitudinal muscle fibres remained normal after the SILT procedure. There were no signs of chronic ischemia or collagen accumulation after the SILT. The myenteric and submucosal plexuses and the Cajal cell network appeared normal.

Conclusion

The bowel remained viable macroscopically and microscopically after SILT, such that SILT may be an alternative or an addition to the present technical repertoire of intestinal lengthening. However the limitations of tailoring should be kept in mind.     

Increased expression of insulin-like growth factor in intestinal lengthening by mechanical force in rats

Introduction

A segment of the jejunum could double its length by the application of an axial mechanical force. We hypothesize that this growth is correlated with an increased expression of insulin-like growth factor (IGF-I) in the jejunum.

Methods

Adult Sprague-Dawley rats underwent the isolation of a 1.5-cm segment of the jejunum. The isolated jejunal segment was either lengthened using mechanical force or left alone for 3 weeks. The jejunal segments were analyzed by quantitative polymerase chain reaction and immunofluorescence for the expression of IGF-I.

Results

Whereas jejunal segments that underwent isolation alone did not change their length, isolated jejunal segments that were stretched by applying a gradual mechanical force doubled their initial length. Both groups increased their muscular thickness 5 folds as compared to the normal jejunum. The mRNA level of IGF-I in the lengthened jejunum was 6 folds higher than that in the normal jejunum, but the IGF-I mRNA level in the isolated jejunum without mechanical lengthening was unchanged. By immunofluorescence, the increased IGF-I expression in the lengthened jejunum was localized to the intestinal smooth muscle cells.

Conclusions

Insulin-like growth factor I may be an important signal induced by the applied axial force that mediates longitudinal intestinal growth.     

Electromagnetic interference caused by common surgical energy-based devices on an implanted cardiac defibrillator

Background

Surgical energy-based devices emit energy, which can interfere with other electronic devices (eg, implanted cardiac pacemakers and/or defibrillators). The purpose of this study was to quantify the amount of unintentional energy (electromagnetic interference [EMI]) transferred to an implanted cardiac defibrillator by common surgical energy-based devices.

Methods

A transvenous cardiac defibrillator was implanted in an anesthetized pig. The primary outcome measure was the average maximum EMI occurring on the implanted cardiac device during activations of multiple different surgical energy-based devices.

Results

The EMI transferred to the implanted cardiac device is as follows: traditional bipolar 30 W .01 ± .004 mV, advanced bipolar .004 ± .003 mV, ultrasonic shears .01 ± .004 mV, monopolar Bovie 30 W coagulation .50 ± .20 mV, monopolar Bovie 30 W blend .92 ± .63 mV, monopolar instrument without dispersive electrode .21 ± .07 mV, plasma energy 3.48 ± .78 mV, and argon beam coagulator 2.58 ± .34 mV.

Conclusion

Surgeons can minimize EMI on implanted cardiac defibrillators by preferentially utilizing bipolar and ultrasonic devices.     

Enterogenesis by mechanical lengthening: morphology and function of the lengthened small intestine

Background/Purpose

The purpose of this study is to evaluate the function of the mechanically lengthened small intestine.

Methods

A jejunal segment was separated from intestinal continuity in rats. A screw was inserted into its proximal end, and the distal end was oversewn. The screw was advanced into the jejunal segment by 5 mm every other day. The jejunal segments were retrieved after 2 weeks. The length, weight, muscular thickness, alkaline phosphatase, and lactase activities of the jejunal segments were determined. Comparisons were made among normal jejunum, isolated jejunal segments without lengthening, and lengthened jejunal segments.

Results

Jejunal segments doubled in length after gradual mechanical stretching compared with the normal and isolated controls. The thickness of the muscular layer increased in both the isolated and lengthened groups. The total activity of alkaline phosphatase increased in jejunal segments that were lengthened, whereas the total lactase activity remained the same.

Conclusions

Mechanical force is a viable method for increasing intestinal length while preserving the intestinal function. This phenomenon may provide a new method for the treatment of patients with short bowel syndrome.     

Development of an endoluminal intestinal lengthening capsule

PurposePrior studies demonstrated the ability of a spring to lengthen intestinal segments. We made two innovations to this device. First, we employed a degradable capsule to control the deployment of the spring. Second, we decreased the spring force to allow slower expansion of the intestinal segment.MethodsNitinol springs with varying forces were compressed and placed in gelatin capsules. These capsules were coated with a degradable polymer and were placed in isolated segments of rat jejunum. Serial x-rays were used to determine the rate of spring expansion. Retrieved jejunal segments were analyzed histologically.ResultsUsing the polymer-coated capsule, the spring was reliably deployed between 24 and 48 hours. Intestinal segments were lengthened from 1.0 cm to 3.6 cm after 14 days. The optimal spring for the gradual expansion of jejunal segments had a spring constant of 0.0010 N/mm. Villus height was preserved, but crypt depth was significantly greater in the lengthened intestine.ConclusionUse of a low-force spring resulted in a nearly four-fold lengthening of jejunal segments. The use of a polymer-coated capsule provided a reliable way to control the timing of spring deployment. This capsule may be useful for the endoscopic placement of the spring in patients with short bowel syndrome.     

Early results of an objective feedback-directed system for the staged traction repair of long-gap esophageal atresia

Purpose

Treatment of long-gap esophageal atresia challenges pediatric surgeons. Dr. Foker described utilization of external traction sutures to promote in-vivo growth through tension-induced lengthening, but reproducibility of this technique is difficult. We describe a safe and reproducible traction system using transduction of hydrostatic pressure as a surrogate for tension.

Methods

We conducted a multi-institutional review of patients treated with this system from 2005 to 2012. All children had sutures applied to both pouches with continuous measurement of associated hydrostatic pressures (tension). Main outcome measures were days to delayed primary repair and thoracotomies prior to primary repair.

Results

Seven children were included. Median time to delayed repair was 15 days (range: 6–47 days). Three patients required repeat thoracotomies owing to mechanical entrapment of a pouch, all identified early by this system. All required postoperative dilations. Three had self-limited postdilation leaks, and there was one operation-related leak.

Conclusions

This system provides reproducible traction application, facilitating staged primary repair by preventing major failures through limiting excessive traction and guides re-exploration for trapped segments. Larger studies are needed to determine the optimal tension protocol, prevent postoperative leaks, while decreasing the need for dilations and time to enteral feeding.     

The 2 STEP: an approach to repeating a serial transverse enteroplasty

Purpose

The serial transverse enteroplasty procedure (STEP) procedure is a successful and safe approach to lengthen small bowel in patients with short bowel syndrome (SBS). However, postlengthening dilatation may occur, which can lead to bacterial overgrowth and malabsorption. We addressed this problem by reperforming the STEP in 2 patients.

Methods

Two infants underwent the STEP procedure at 3 days and at 4 months of life for SBS secondary to intestinal atresia and gastroschisis. The patients' small bowel lengths were 20 and 32 cm before and 25 and 52 cm after the initial STEP. Nine and 8.5 months afterward, the patients developed dilatation of the small bowel and feeding intolerance. A second STEP procedure was undertaken with additional transverse firings of staplers between previously lengthened segments and tapering of redundant blind-ending portions of bowel.

Results

At operation, the bowel lengths were 45 and 62 cm. The second STEP left the patients with 61 and 73 cm of small bowel with a normalization of intestinal diameter. The first patient is doing well 5 months after surgery, and the second child tolerated increased enteral intake but died 1 year later from total parenteral nutrition-related liver failure.

Conclusions

This is the first report of a successful application of a second STEP procedure to further lengthen small bowel in SBS patients. Reapplication of the procedure requires careful stapling and a removal of small blind-ending segments to avoid further stasis.     

Intermediate outcomes after serial transverse enteroplasty in children with short bowel syndrome

Background

Serial transverse enteroplasty (STEP) is a novel intestinal lengthening procedure introduced in 2003. To date, no human studies exist that report objective assessment of intestinal absorptive capacity. The aim of this study was to report intermediate outcomes in patients who have received the STEP at our institution using clinical and biochemical assessment of intestinal function.

Methods

All 14 patients who received the STEP since May 2003 were reviewed. Clinical (weight gain, enteral tolerance, stool frequency) and biochemical (citrulline levels, d-xylose absorption, alpha-1 antitrypsin clearance, and fecal fat content) outcomes were performed pre-STEP and post-STEP at 1, 6, and 12 months, respectively. Data are presented as means with standard deviation. Paired t tests were used to compare post-STEP outcomes with pre-STEP values (P < .05 was significant). Three patients had a STEP as a newborn and are analyzed separately.

Main Results

There were 14 patients (3 females; mean age, 24.8 months; range, 1 day-14 years). Serial transverse enteroplasty resulted in a mean increase in length of dilated bowel segment of 94% ± 30% and increase in total small bowel length of 49% ± 42% with mean application of 16 ± 9 cartridges and cost of Can$2878.51 ± 1406.22. Patients demonstrated improvement in both clinical parameters, as well as intestinal absorptive function. Complications included 2 patients with staple line leak and 1 patient with gastrointestinal bleeding from staple line ulcers. Three patients died (2 from liver failure and 1 from sepsis and congenital heart disease). Two patients received liver-intestinal transplants at 4 and 5 months post-STEP. Mean follow-up was 23 ± 9 months, with 7 patients followed more than 2 years. Of 8 patients with post-STEP follow-up of more than 1 year, 7 have weaned from parenteral nutrition.

Conclusion

Clinical and objective biochemical outcomes of intestinal function after the STEP procedure show promise after intermediate follow-up.     

Stabilization of multiple rib fractures in a canine model

Background

Operative stabilization is frequently used in the clinical treatment of multiple rib fractures (MRF); however, no ideal material exists for use in this fixation. This study investigates a newly developed biodegradable plate system for the stabilization of MRF.

Methods

Silk fiber-reinforced polycaprolactone (SF/PCL) plates were developed for rib fracture stabilization and studied using a canine flail chest model. Adult mongrel dogs were divided into three groups: one group received the SF/PCL plates, one group received standard clinical steel plates, and the final group did not undergo operative fracture stabilization (n = 6 for each group). Radiographic, mechanical, and histologic examination was performed to evaluate the effectiveness of the biodegradable material for the stabilization of the rib fractures.

Results

No nonunion and no infections were found when using SF-PCL plates. The fracture sites collapsed in the untreated control group, leading to obvious chest wall deformity not encountered in the two groups that underwent operative stabilization.

Conclusions

Our experimental study shows that the SF/PCL plate has the biocompatibility and mechanical strength suitable for fixation of MRF and is potentially ideal for the treatment of these injuries.     

Double plication for spring-mediated in-continuity intestinal lengthening in a porcine model

Background

Short bowel syndrome is a condition with substantial morbidity and mortality, yet definitive therapies are lacking. Distraction enterogenesis uses mechanical force to “grow” new intestine. In this study, we examined whether intestinal plication can be used to safely achieve spring-mediated intestinal lengthening in a functioning segment of jejunum in its native position.

Distension enterogenesis: increasing the size and function of small intestine

Introduction

The purpose of this study is to evaluate the feasibility of using saline infusion to lengthen small bowel while preserving intestinal enzymatic function.

Methods

Male Sprague-Dawley rats had a 3-cm jejunal segment taken out of continuity. A catheter was inserted in the proximal end, and the distal end was oversewn. Continuous infusion of saline into the isolated jejunal segment was started 2 weeks postoperatively. Segments were harvested 1 week later. Segment weights and lengths were measured preoperatively and at the time of harvest. Histology of harvested segments was performed. Alkaline phosphatase (ALP) and lactase assays were performed. Comparisons were made with normal jejunum from control animals.

Results

A 32% increase in length was achieved with saline distension of small intestine. The segment weight to length ratio was significantly increased by saline distension; however, the total protein-to-weight ratio was unchanged. Specific activities of ALP and lactase were not affected by saline distension. Because of the increased length and weight of the distended jejunal segments, total segment activities for both enzymes were significantly increased.

Conclusions

Saline infusion appears to be a viable method for increasing small intestinal length without compromising enzymatic function. This phenomenon may provide a new method for the treatment of patients with short bowel syndrome in the future, and further study is warranted.     

Leg lengthening using intramedullay skeletal kinetic distractor: Results of 57 consecutive applications

Background

Mechanically activated intramedullary lengthening nails are advantageous over external fixator. However, difficulties with the control of the distraction rate are the main drawbacks, which may in turn cause insufficient bone regenerate.

Patients and methods

A total of 57 lengthening procedures were performed using intramedullary skeletal kinetic distractor (ISKD) nail in 53 patients (femoral = 45 and tibial = 12). Average length gain was 4.3 ± 1.6 cm. The cause of shortening was post-traumatic (n = 33), congenital (n = 20), post-tumour resection (n = 1), cosmetic femoral lengthening (n = 2) and post-correction of distal femoral varus deformity (n = 1).

Results

The desired lengthening was achieved in all patients. The mean follow-up period was 23 ± 12 months. The healing index for patients with normal bone healing was 1.2 ± 0.32 months/cm. Complications in femoral lengthening were superficial wound infection (n = 1), premature consolidation (n = 4) and insufficient bone regenerate (n = 11), while in the tibial lengthening, two developed equinus contractures, one had compartment syndrome following implantation of the nail and one insufficient bone regenerate. Furthermore, nine runaway nails and three non-distracting nails were present in the femoral lengthening. One non-distracting nail responded to manipulation under anaesthesia, one required exchange nailing and accidental acute lengthening of 3 cm took place while manipulating the third nail. Patients with femoral lengthening and those with insufficient regenerate had significantly higher distraction rates (P = 0.006 and 0.003, respectively). Six out of the nine runaway nails developed insufficient bone regenerate. In addition, 10.7-mm tibial ISKD nails were found to have lower rates of runaway nails compared with other used diameters.

Conclusion

We emphasise the rule of distraction rates above 1.5 mm/day in the development of insufficient bone regenerate. Distraction problems with these nails are mostly due to dysfunction within the ratcheting mechanism, which may be related to the diameter of the nail. New designs for mechanically activated nails with a better control mechanism for the distraction rate are required.     

Examining Hemodialysis Reliable Outflow catheter performance and cost in hemodialysis access

Background

The Hemodialysis Reliable Outflow (HeRO) vascular access device is a hybrid polytetrafluoroethylene graft-stent construct designed to address central venous occlusive disease. Although initial experience has demonstrated excellent mid-term patency rates, subsequent studies have led to external validity questions. The purpose of this study was to examine a single center experience with this vascular access device in challenging access cases with associated costs.

Methods

A retrospective study representing the authors' cumulative HeRO vascular access device experience was undertaken. The primary endpoint was graft failure or death, with secondary endpoints including secondary intervention rates and cost.

Results

Forty-one patients with 15,579 HeRO days and a mean of 12.7 ± 1.5 mo with the vascular access device were available for analysis. Secondary patency was 81.6% at 6 mo and 53.7% at 12 mo. The reintervention rate was 2.84 procedures per HeRO vascular access device year. Associated HeRO costs related to subsequent procedures were estimated at $34,713.63 per patient/y.

Conclusions

These data on the patency and primary outcome data diverge significantly from initial multicenter studies and represent a real-world application of this technology. It is costly to maintain patency. Use of HeRO vascular access devices should be judicious with outcome expectations reduced.