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Background: Pulsed radiofrequency energy (PRFE) has long been reported to have a therapeutic effect on postoperative pain. In this study, a portable, wearable, low-energy-emitting PRFE therapy device was used to determine the control of postoperative pain after breast augmentation surgery., Methods: The study enrolled 18 healthy women who underwent breast augmentation purely for aesthetic considerations. Postoperative pain after surgery was assessed with a 0- to 10-point visual analog scale (VAS). Baseline pain scores were taken at completion of the operation, and the patients were randomly assigned coded PRFE devices that were either active or placebo devices. For 7 days, VAS scores were recorded twice daily (a.m. and p.m.). Medication use also was logged for 7 days. The PRFE devices were left in place and in continuous operation for the 7 days of the study., Results: All the patients tolerated the PRFE therapy well, and no side effects were reported. The VAS scores for the active group were significantly lower on postoperative day 1. By day 7, the baseline VAS remaining in the active group was 7.9% versus 38% in the placebo group. Together with lower VAS scores, narcotic pain medication use was lower in the patient group that received PRFE therapy., Conclusion: Postoperative pain is significantly lower with PRFE therapy. According to the findings, PRFE therapy in this form is an excellent, safe, drug-free method of postoperative pain control.

Purpose: Distraction osteogenesis (DO) is an effective way to treat severe maxillary deficiency in patients with cleft lip and palate. It has been reported to have long-term stability and low relapse rate compared with conventional maxillary osteotomy in large maxillary movement. However, complications such as nonunion are seldom reported. While developing our external distraction techniques, we had 4 nonunion cleft lip and palate (CLP) patients. The aim of this study is to analyze the possible reasons for these conditions by comparing them to patients successfully treated at 1 craniofacial institute., Patients and Methods: Fifty-six patients with CLP deformities treated with external maxillary distraction from 2000 to 2006 in 1 craniofacial center were reviewed. Among them, 17 had full records and follow-up time of more than 1 year. They had rigid external halo distraction with dental splint after a high Le Fort I osteotomy. Distraction was started at 5 days with a rate of 1 mm per day until the maxilla acquired the planned correction. Consolidation time ranged from 4 weeks to 3 months. Patients' general information, DO protocol, and cephalometric radiograph measurements before DO, immediately after DO, and follow-ups were evaluated., Results: Thirteen of 17 patients successfully completed DO, whereas 4 others developed dental occlusion relapse 2 to 3 months after device removal. Later jaw surgery showed nonunion at the distraction sites. These were our first patients treated with external distraction. Their consolidation time was from 4 to 6 weeks with a mean of 5.2 weeks. After increasing the consolidation time up to 12 weeks, all of the other 13 patients had successful results without nonunion. Their mean consolidation time was 9.8 weeks. The nonunion group had significantly shorter consolidation time, older age, and larger distraction osteogenesis (DO) advancement than the successful group statistically. There was also a greater percentage of bilateral CLP patients in the nonunion group than in the successful treatment group. Among the 4 nonunion patients, 2 had failed alveolar bone graft before DO, and 3 did not have face mask retention therapy after device removal. The horizontal relapse rate in the 13 successful patients was 1 to 3 mm (mean, 11.9%) after 1 to 3 years of follow-up. All of these patients had good occlusion in the short-term follow-up (1 yr). Five developed end-to-end or Class III malocclusion in the long-term follow-up (1-3 yrs) because of maxillary relapse and continued mandibular growth that required jaw surgery later., Conclusions: A short consolidation time can cause nonunion, and should be lengthened to 12 weeks or more for a stable maxilla. Older age, bilateral CLP, large DO advancement (>15 mm), and compromised bone healing are the risk factors for nonunion., (Copyright © 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Object: This study was designed to evaluate the bone regeneration potential of the dura mater and dura mater substitute (Durepair) in the presence of recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered in a collagen sponge-collagen-ceramic matrix (CCM; MasterGraft Matrix) in a large skull defect in growing canines., Methods: Forty immature male beagles were used to create two 2.5 x 4-cm cranial defects on each side of the sagittal suture. The dura mater on the left side was cut to make a 1 x 3-cm defect and replaced with bovine skin collagen (Durepair). The dura mater on the right side remained intact. Different doses of rhBMP-2 (none [8 animals], 0.11 mg/ml [4 animals], 0.21 mg/ml [4 animals], and 0.43 mg/ml [8 animals]) were infused on 2 Type I bovine absorbable collagen sponge (ACS) strips. The strips were layered with the CCM (15% hydroxyapatite [HA]/85% tricalcium phosphate [TCP]) to reconstruct both cranial defects. In a fifth group (8 animals), 0.43 mg/ml rhBMP-2 was directly infused into the CCM. Demineralized canine cancellous freeze-dried demineralized bone matrix (DBM; 8 animals) was used as a control in a sixth group. All materials were fixed under 2 resorbable protective sheets (MacroPore). Skulls were resected 16 weeks after operation. Histological and histomorphometric analyses on the percentage of the defect spanned by bone, and the percentage of residual HA-TCP granules and collagen were analyzed., Results: Calcified seroma was the only complication observed and only occurred in the 0.43-mg/ml rhBMP-2 groups (Groups 4 and 5). Dura mater repair appeared complete at 4 months in all animals. New bone was formed sporadically throughout the skull defect in the ACS+CCM and DBM groups without rhBMP-2. In all rhBMP-2 groups, mature new bone (compact and trabecular) was uniformly formed across the defect on both the repaired and intact dura mater sides. There was significant new compact bone formation on top of the repaired dura mater, which did not appear in the ACS+CCM and DBM groups lacking rhBMP-2. Greater HA-TCP and collagen scaffold resorption was noted in rhBMP-2 groups compared with non-rhBMP-2 groups. Statistical analysis showed there was a significantly lower percentage of bone spanning the defect in the ACS+CCM group compared with groups with rhBMP-2, with more residual HA-TCP and collagen on the repaired dura mater side than the intact dura mater side (p < 0.05). In all rhBMP-2 groups, there were no significant differences in new bone formation between the repaired and intact dura mater sides (p > 0.05)., Conclusions: The ACS+CCM combination had an effect similar to demineralized bone-on-bone regeneration in craniofacial reconstruction. The addition of rhBMP-2 to CCM directly or with ACS induces mature new bone formation in large cranial defects both in the presence of intact dura mater and repaired dura mater.

Reconstruction of cranial and maxillofacial defects is a challenging task. The standard reconstruction method has been bone grafting. In this review, we shall describe the biological principles of bone graft healing, as pertinent to craniofacial reconstruction. Different types and sources of bone grafts will be discussed, as well as new methods of bone defect reconstruction.

Objectives: The objective of this study was to evaluate the long-term success of mandibular distraction osteogenesis in patients with mandibular airway obstruction syndrome (MAOS), defined as obstructive sleep apnea, swallowing abnormalities, and failure to thrive in the presence of micrognathia, glossoptosis, gastroesophageal or laryngeal reflux, and microaspiration. This is a cross-sectional study at the International Craniofacial Institute in the Medical City Hospital, Dallas, TX. From January 1997 to July 2008, a group of 81 patients were examined for MAOS using medical history and physical examination. They all met the criteria for a multidisciplinary team evaluation consisting of upper airway endoscopy, swallowing evaluations, standard overnight polysomnography, and radiologic evaluations of the airway and craniofacial structures., Materials and Methods: In the 81 patients examined, Pierre Robin Sequence was diagnosed in 65; micrognathia and glossoptosis without cleft palate, in 13; and micrognathia as a component of a craniofacial syndrome (Treacher Collins syndrome), in 3. A total of 45 patients were documented to have gastroesophageal or laryngeal reflux.Only 41 patients had yet to receive any treatment at the time of evaluation; 40 patients presented with a tracheotomy.Of the 41 untreated patients, 14 responded to conservative treatment; Pierre Robin syndrome was diagnosed in all of them, and they did not require mandibular distraction or other surgical procedure to improve the MAOS.Bilateral distraction osteogenesis of the mandible was performed in 67 patients; 27 were younger than 6 months at the beginning of the distraction, and 40 were older than 6 months (mean age at distraction, 1.2 yr). Of this group, 26 patients did not have any prior surgical treatment, and 41 patients already had a tracheotomy. The distraction devices used were internal in 33 (49.26%) and external in 34 (50.74%) of 67 patients. The distraction protocol consisted of a 24-hour latency period and then a 1-mm/d activation period. The mean activation period was 19.4 days (range, 10-27 d), the mean consolidation period was 73 days, and the mean length of distraction was 22 mm (range, 10-32 mm)., Results: Tracheostomy was prevented in 25 (96%) of 26 patients, and decannulation after distraction was possible in 38 (92%) of 41 patients. Success, defined as decannulation within 1 year of the start of distraction or prevention of tracheostomy in a patient otherwise deemed as a candidate, was found in 63 (94%) of 67 patients. Oral feedings have been resumed in 61 (91%) of 67 patients.Complications observed were mostly related to pin site infections requiring antibiotics. Device failure was experienced in 2 (3%) of 66 internal devices and in 7 (10.2%) of 68 external devices.Distraction osteogenesis of the mandible provides an excellent treatment for mandibular airway obstruction in patients younger than 6 years who do not respond to conservative measures and allows for early decannulation in patients who previously underwent tracheotomy.

This study was designed to investigate the optimal combination of known osteogenic biomaterials with shape conforming struts to achieve calvarial vault reconstruction, using a canine model. Eighteen adolescent beagles were divided equally into 6 groups. A critical-size defect of 6 x 2 cm traversed the sagittal suture. The biomaterials used for calvarial reconstruction were demineralized perforated bone matrix (DBM), recombinant human bone morphogenetic protein 2 (rhBMP2), and autogenous platelet-rich plasma (PRP). The struts used were cobalt chrome (metal) or resorbable plate. The groupings were as follows: 1) DBM + metal, 2) DBM + PRP + metal, 3) DBM + PRP + resorbable plate, 4) DBM + rhBMP2 + metal, 5) DBM + rhBMP2 + PRP + metal, and 6) DBM + rhBMP2 + resorbable plate. Animals were killed at 3 months after surgery. There was no mortality or major complications. Analysis was performed macroscopically and histologically and with computed tomography. There was complete bony regeneration in the rhBMP2 groups only. Non-rhBMP2 groups had minimal bony ingrowth from the defect edges and on the dural surface, a finding confirmed by computed tomographic scan and histology. Platelet-rich plasma did not enhance bone regeneration. Shape conformation was good with both metal and resorbable plate. rhBMP2, but not PRP, accelerated calvarial regeneration in 3 months. The DBMs in the rhBMP2 groups were substituted by new trabecular bone. Shape molding was good with both metal and resorbable plate.

The aim was to assess the stability of monobloc distraction osteogenesis using three-dimensional computed tomographic (CT) scan volume-rendered images with the "biporion-dorsum sellae" plane. This was a prospective study of patients undergoing monobloc internal distraction osteogenesis at the International Craniofacial Institute, Dallas, TX. Measurements were made of the perpendicular distance of 8 skeletal facial points to the static "biporion-dorsum sellae" plane. The statistical analyses were performed with the paired-samples t test in SPSS. Three male patients were included in the study. Of these patients, 2 had Apert syndrome (A, B) and 1 had Carpenter syndrome (C). The mean age was 73 (range 30-112) months, and the mean follow up was 14 (range 8-12) months. The consolidation period was 17, 23, and 28 weeks in each patient, respectively. In patient A, the paired-samples t test of matched points was P = 0.022. Further analysis of the three-dimensional lateral profile revealed an obvious relapse, and predistractor removal CT scans (at 17 weeks) also showed deficient bone growth across the distraction gaps at the anterior cranial fossae and the temporal bones. In contrast, patients B and C showed a stable outcome after distraction and after removal of distraction devices. On analysis of the predistractor removal three-dimensional CT scans (23 and 28 weeks, respectively), there was more bone growth across the distraction gaps at the anterior cranial fossa and temporal bones. The "biporion-dorsum sellae" plane was used to assess the results of monobloc distraction osteogenesis. Relapse was associated with inadequate bone growth across the anterior cranial fossa and temporal bone. The findings seem to point the way for an increased consolidation period and more detailed examination of the CT scans before removal of internal distraction devices.

Purpose: Cranial defect reconstruction presents 2 challenges: induction of new bone formation, and providing structural support during the healing process. This study compares quantity and quality of new bone formation based on various materials and support frameworks., Materials and Methods: Eighteen dogs underwent surgical removal of a significant portion of their cranial vault. Demineralized bone matrix was used to fill the defect in all animals. In 9 dogs, recombinant human bone morphogenetic protein-2 (rhBMP-2) was added, while the other 9 served as the non-rhBMP-2 group. In each group, 3 animals were fixed with cobalt chrome plates, 3 with adding platelet-rich plasma, and 3 fixed with a Lactosorb (Walter Lorenz Surgical, Inc, Jacksonville, FL) resorbable mesh. Necropsy was done at 12 weeks postoperative. Histomorphometry, density, and mechanical properties of the regenerate were analyzed., Results: The non-rhBMP-2 groups showed minimal substitution of demineralized bone matrix with new bone, while only sporadic remnants of demineralized bone matrix were present in the rhBMP-2 groups. The defect showed more new bone formation (P < .001) and density (P < .001) in the rhBMP-2 groups by Kruskal-Wallis test. The area of new bone was not significantly different among the rhBMP-2 subgroups. The resorbable mesh struts showed no sign of bone invasion or substitution. In the non-rhBMP-2 resorbable mesh group, demineralized bone matrix almost totally disintegrated without replacement by new bone., Conclusions: The addition of rhBMP-2 to demineralized bone matrix accelerated new bone formation in large cranial defects, regardless of the supporting framework or the addition of platelet-rich plasma. The use of a resorbable mesh in such defects is advisable only if rhBMP-2 is added.

Background: Choice of bone replacement materials is important when reconstructing large craniofacial defects. Hydroxyapatite cements are often used for such reconstructions. Recent advances in the development of these cements have produced locally applied, in situ hardening materials excellent for use in craniofacial defects. To date, there has been a paucity of data comparing the use of calcium phosphate cements in combination with titanium or resorbable plating systems and their combined biocompatibility. An experimental dog model was used to compare these systems., Methods: Two 4 x 4-cm calvarial defects were created in each of 18 mongrel dogs, and defects were reconstructed with calcium phosphate cement with either titanium or resorbable mesh sheets to evaluate their interaction. Specimens were harvested and evaluated histologically for the development of new bone formation at 3, 6, and 12 months., Results: At 3 months, no differences were noted in the amount of bone formed between titanium and resorbable plating. By 6 months, the resorbable mesh sheet showed delayed bone formation compared with the titanium mesh. At 12 months, bone formation over the resorbable mesh accelerated to be no different from the titanium mesh. Importantly, new bone formation was seen within the monocalcium phosphate cement Norian Craniofacial Repair System on a reliable basis, regardless of mesh plate used., Conclusions: There are no long-term adverse effects with the use of Norian cement with either titanium or resorbable mesh. However, further studies need to be conducted to determine why there is an arrested healing phase between 3 and 6 months with the Norian cement and resorbable plating materials.

Objective: This study was designed to investigate the optimal combination of known osteogenic biomaterials with shape conforming struts to achieve calvarial vault reconstruction, using a canine model., Methods: Eighteen adolescent beagles were divided equally into 6 groups. A critical size defect of 6 x 2 cm traversed the sagittal suture. The biomaterials used for calvarial reconstruction were demineralised perforated bone matrix (DBM), recombinant human bone morphogenetic protein-2 (rhBMP2) and autogenous platelet-rich plasma (PRP). The struts used were cobalt chrome (metal) or resorbable plate. The groupings were as follows: 1) DBM + metal, 2) DBM + PRP + metal, 3) DBM + PRP + resorbable plate, 4) DBM + rhBMP2 + metal, 5) DBM + rhBMP2 + PRP + metal, and 6) DBM + rhBMP2 + resorbable plate. Animals were euthanised at 3 months post-surgery. There was no mortality or major complications. Analysis was performed macroscopically, histologically, and with computed tomography (CT)., Results: There was complete bony regeneration in the rhBMP2 groups only. Non-rhBMP2 groups had minimal bony ingrowth from the defect edges and on the dural surface, a finding confirmed by CT scan and histology. PRP did not enhance bone regeneration. Shape conformation was good with both metal and resorbable plate., Conclusion: rhBMP2 but not PRP accelerated calvarial regeneration in 3 months. The DBM in the rhBMP2 groups were substituted by new trabecular bone. Shape molding was good with both metal and resorbable plate.

Although facial deformity can accurately be described and classified, the treatment goal can be more difficult to define. Functional and esthetic endpoints calibrated to a set of normal facial proportions may achieve a "normal" face but one that is not necessarily beautiful. Results of orthognathic surgery can dramatically be improved by adding an aesthetic concept to the surgical plan. We can achieve a face with both stable occlusion and a beautiful look each time. Additional soft tissue procedures may be required to perfect the final balance and harmony of the face.

Background: The aim of this study was to investigate the prevalence of abnormal preoperative screening prothrombin time and partial thromboplastin time in patients listed for primary cranial vault remodeling that required hematologic workup and their diagnoses and subsequent management., Methods: This retrospective analysis was performed from January of 2000 to December of 2003 at the International Craniofacial Institute, Dallas, Texas, on a total of 168 patients., Results: All patients had a normal prothrombin time. Abnormally raised partial thromboplastin time was found in six patients (prevalence of 3.57 percent), one who had factor XI deficiency, one who had a borderline factor XI deficiency and circulating inhibitor, one who had an intermittent factor XI deficiency and circulating inhibitor, one who had a borderline von Willebrand's disease with low factor XII, and the remaining two who had a circulating inhibitor of coagulation. Of these six patients, the perioperative management was altered in four of five patients, and one patient declined surgery out of fear of surgical morbidity. The surgery of one patient was aborted intraoperatively because of abnormal bleeding without clot formation after the calvarial burr holes had been drilled. The mean blood loss was 183 ml for the four patients with completed surgery and 100 ml for one patient., Conclusions: The authors conclude that even though the prevalence of abnormal screening partial thromboplastin time in these patients was low (3.57 percent), detection of an abnormal result required preoperative correction of coagulopathy in 80 percent of cases.

The results of craniofacial and orthognathic surgery have traditionally been monitored using lateral cephalometry. In the age of computed tomography (CT) and magnetic resonance imaging (MRI), newer methods of measuring surgical outcome have arisen. This has been further enhanced by the use of computer software to render CT images in a three-dimensional format. The authors present a novel method of measuring the outcome of monobloc distraction osteogenesis advancement using the biporion-dorsum sellae plane. The perpendicular distance of eight facial skeletal points to this plane were made automatically using the Vworks 4.0 program. A total of 10 measurements were made against six planes of reference. Planes 1, 2, 3, 1+2 degrees, and 1-2 degrees were constructed, and measurements were made by observer 1. Plane 6 was constructed and measurements were made by observer 2. Plane 1 was used as the denominator on which calculations were made. The results revealed a mean intra- and interobserver percentage difference from plane 1 of less than 5%. In addition, the overall mean intraobserver variance of all eight points from observer 1 was 0.91%, and the mean interobserver variance between observer 1 and 2 was 0.73%. In summary, based on the authors' method, repeated measurements made from the biporion-dorsum sellae plane have proven precision and reproducibility.

Good to excellent results have consistently been achieved by the authors in primary unilateral cleft lip-nose repair. Modifications and improvements in their original technique have led to better symmetry and balance, with less scarring. This technique, when performed by experienced surgeons, yields consistent, predictable, and achievable outcomes for all patients with unilateral cleft lip and nose, where normal appearance and function at conversational distance is the standard of care. The achievement of excellence in soft tissue and skeletal restoration optimizing each patient's growth potential depends on a surgical-orthodontic-speech-oriented treatment plan. Long-term outcomes demonstrating consistently good to excellent results can be achieved using this primary technique if it is backed up with a dedicated, multidisciplinary ongoing treatment protocol.

A 33-year experience with a proven method of repair for primary unilateral cleft lip-nose is presented. The technique used by the authors has been improved by modifications that have led to better symmetry and balance with less scarring. The technique involves ignoring the abnormal skeletal base, use of perisurgical passive orthopedics, and primary surgical correction of the nose and lip. Improved results can consistently be achieved by approaching the nose laterally through an inferior turbinate incision, freeing completely the lip and nose components so they can be translocated to match the normal side. Accurate positioning and symmetry of the alar base and sill is aided by limiting the transverse incision in the lip. This results in less scarring and improved sill reconstruction. The technique for floor-of-the-nose reconstruction avoids a small nostril without discarding any tissue. It is important to leave tissue in the floor to compensate for the skeletal deficiency. The senior author has performed this procedure in more than 750 patients. Approximately 35% have or will require minor secondary reconstruction at age 5 years. An aesthetic rhinoplasty is performed on most patients after growth is complete. Self-esteem is enhanced by early nasal reconstruction and has become the authors' standard of care for rehabilitation of the unilateral cleft lip and palate. Many surgeons remain reluctant to perform primary nasal repair. With careful proper technique, any experienced cleft surgeon can learn this procedure. For the beginner, conservatism is recommended.

Degloving injuries of the hand and foot pose difficult reconstructive and rehabilitation challenges. After an excellent experience with split-thickness skin grafting with the vacuum-assisted closure device, we began studies with full-thickness skin grafts and traumatized skin. The device has been used with successful reapplication of full-thickness degloved skin in two patients. The first patient suffered degloving of the foot; the second patient, degloving of the hand.

Craniosynostosis, the premature fusion of one or more cranial sutures, may occur in isolation or in association with a syndromic constellation. Multiple-suture synostosis has consistently been associated with brain compression and increased intracranial pressure, and frequently decreased cognitive development. Single-suture craniosynostosis, however, has been thought by some to be an aesthetic problem with infrequent consequences on brain function and development. Some studies have disputed this concept and have argued a correlation between single-suture craniosynostosis and abnormalities in development. The purpose of this study was to determine, using an objective radiographic tool, positron emission tomography scans, if patients with single-suture craniosynostosis had any abnormalities in cerebral glucose metabolism that would indicate changes in local brain function. A total of 10 children with single-suture craniosynostosis, eight males and two females, ranging in age from 0.1 to 3.2 years, were enrolled in this prospective study approved by the Internal Review Board. Six of the children had sagittal synostosis, three had metopic synostosis, and one had coronal craniosynostosis. Each of the patients had preoperative positron emission tomography scans performed 1 to 5 weeks before cranial reconstructive surgery and postoperative scans at 6 to 12 weeks after surgery. Surgical treatment consisted of cranial vault remodeling in eight of the children and strip craniectomy with cranial expansion in two of the children. After surgery, the two scans were compared qualitatively and quantitatively by a single radiologist. The results demonstrated variable regional increases and decreases in local post-operative cerebral glucose metabolism. However, in the posterior occipital region, the area of visual development and visual spatial coordination, there was a consistent postoperative increase in all 10 patients. Maximum glucose metabolic rate was increased up to 30.2% with a mean of 9.9%, and average glucose metabolic rates demonstrated a maximum increase of up to 18.8%. The results of this study indicate cerebral glucose metabolism consistently increases in the posterior occipital cortex after surgical release of single-suture craniosynostosis. Future developmental studies are being performed to examine the functional consequences of these metabolic changes.

The ability to increase the rate of skin graft donor site reepithelialization significantly in a cost-effective manner has important implications for the patient undergoing major reconstructive procedures. In this study the effect of externally applied reduced pressure (the V.A.C.) on the rate of healing of donor site wounds was initially investigated using a porcine model (N = 4), then repeated on humans (N = 10). Split-thickness skin grafts were harvested from the backs of pigs using standard technique. Half of the donor sites were treated with subatmospheric pressure (125 mmHg) and half were treated with an OpSite dressing. Biopsies taken every 48 hours demonstrated that sites exposed to reduced pressure healed at a much faster rate than sites treated with a standard occlusive dressing. Similarly, donor sites in humans reepithelialized faster in 7 of 10 patients, the rate was the same in 2 of 10 patients, and OpSite was faster in 1 of 10 patients. We believe this technology has the potential to be a relatively simple and cost-efficient method for increasing the rate of donor site healing.

Background: Spontaneous rupture of abdominal aortic aneurysm into the inferior vena cava is rare. The clinical presentation is highly variable, and the diagnosis can be difficult, often being made only at operation. The aortocaval fistula results in a large left-to-right shunt, which can cause cardiac failure. Once the diagnosis is made, treatment is by surgical closure of the fistula and repair of the aneurysm with a graft., Methods: This is a retrospective review of a single surgeon's experience with aortocaval fistula complicating abdominal aortic aneurysms., Results: Over a 15-year period, we had five patients with spontaneous aortocaval fistula who were treated operatively. Preoperative diagnosis was made in two, suspected in one, and not made in two, one of whom died (the only perioperative death in the series)., Conclusions: Spontaneous aortocaval fistulas are uncommon, and their preoperative recognition is difficult. Hematuria in association with an abdominal aortic aneurysm should raise the suspicion of an aortocaval fistula. Surgical correction is possible, with survival rates comparable to those associated with rupture of aneurysms into the retroperitoneum. Early operative control of the fistula is important to optimize the preload to the heart.

Ventricular assist devices augment flow from the left atrium to the aorta and/or from the right atrium to the pulmonary artery. Most devices are used in the asynchronous full-to-empty mode (asynchronous) but may also be used in a synchronous counterpulsation mode (synchronous). This study determines the optimal assist modes to reduce myocardial oxygen consumption (MVO2) and metabolism. Twelve pigs were instrumented with carotid artery and Baim coronary sinus catheters for determination of MVO2 and myocardial lactate production (LACT). Six were implanted with a Pierce-Donachy left ventricular assist device (LVAD) and 6 with both right and left ventricular assist devices (BIVAD). Two periods each of control, synchronous, and asynchronous bypass were instituted, the midanterior descending coronary artery (LAD) was ligated, and the sequence was repeated. After each period, MVO2 and LACT were determined and myocardial biopsy specimens were obtained for tissue, lactate, and ATP assay. Following LAD ligation, biopsy specimens were obtained from both the infarct and noninfarct zones of the heart. MVO2 decreased (p < 0.05) in the asynchronous BIVAD mode compared with control. MVO2 was unchanged in synchronous BIVAD or either LVAD mode. Tissue ATP and tissue lactate were unaffected by any mode of bypass. Only BIVAD in the asynchronous mode reduced MVO2. When ventricular assist devices are utilized to aid recovery of the natural heart, two devices should always be inserted to allow biventricular assist. Synchronous counterpulsation offers no advantage.

Ventricular assist devices augment aortic or pulmonary flow while the patient's heart recovers from surgery or infarction. Most are used in the asynchronous full-to-empty mode, but they also may be used in a synchronous counter-pulsation mode. This study examines which assist mode optimally reduces myocardial oxygen consumption (MVO2). Eighteen pigs were instrumented with pulmonary artery, carotid artery, and coronary sinus catheters for determination of MVO2. Pierce-Donachy Ventricular Assist Devices (VAD) were used in left, right, or biventricular assist mode. Fifteen minute periods each of control, synchronous, and asynchronous bypass were randomly instituted. The mid-left anterior descending coronary artery was then ligated, and the sequence repeated. At the end of each period, MVO2 was determined. In comparison with controls, MVO2 was statistically significant in the BIVAD asynchronous mode only. Synchronized counterpulsation did not decrease MVO2. When ventricular assist devices are used to aid in cardiac recovery postoperatively or postmyocardial infarction, biventricular assist should be used.