Steven D. Schwaitzberg

A New Characterization of Injury Severity

ASCOT (A Severity Characterization of Trauma) is a physiologic and anatomic characterization of injury severity which combines emergency department admission values of Glasgow Coma Scale, systolic blood pressure, respiratory rate, patient age, and AIS-85 anatomic injury scores in a way that obviates ISS shortcomings. ASCOT values are related to survival probability using the logistic function and regression weights reaffirm the importance of head injury and coma to the prediction of patient outcome. The ability of TRISS and ASCOT to discriminate survivors from non-survivors and the reliability of their predictions, as measured by the Hosmer-Lemeshow statistic, were compared using Major Trauma Outcome Study (MTOS) patient data. ASCOT performance matched or exceeded TRISSs for blunt-injured patients and for penetrating-injured patients. ASCOT performance gains were modest for blunt-injured patients. The Hosmer-Lemeshow statistics suggest that ASCOT reliably predicts patient outcome for penetrating-injured patients and nearly so for blunt-injured patients. Statistically reliable predictions were not achieved by TRISS for either set. ASCOT provides a more precise description of patient physiologic status and injury number, location, and severity than TRISS. The ASCOT patient description may be useful in relating to other important outcomes not highly correlated with TRISS or the Injury Severity Score (ISS) such as disability, length of stay, and resources required for treatment.

A consensus document on robotic surgery

“Robotic surgery” originated as an imprecise term, but it has been widely used by both the medical and lay press and is now generally accepted by the medical community. The term refers to surgical technology that places a computer-assisted electromechanical device in the path between the surgeon and the patient. A more scientifically accurate term for current devices would be “remote telepresence manipulators” because available technology does not generally function without the explicit and direct control of a human operator. For the purposes of the document, we define robotic surgery as a surgical procedure or technology that adds a computer technology–enhanced device to the interaction between a surgeon and a patient during a surgical operation and assumes some degree of control heretofore completely reserved for the surgeon. For example, in laparoscopic surgery, the surgeon directly controls and manipulates tissue, albeit at some distance from the patient and through a fulcrum point in the abdominal wall. This differs from the use of current robotic devices, whereby the surgeon sits at a console, typically in the operating room but outside the sterile field, directing and controlling the movements of one or more robotic arms. Although the surgeon still maintains control over the operation, the control is indirect and effected from an increased distance. This definition of robotic surgery encompasses micromanipulators, remotely controlled endoscopes, and console-manipulator devices. The key elements are enhancements of the surgeon’s abilities—be they vision, tissue manipulation, or tissue sensing—and alteration of the traditional direct local contact between surgeon and patient.

Comparison of poly-N-acetyl glucosamine (P-GlcNAc) with absorbable collagen (Actifoam), and fibrin sealant (Bolheal) for achieving hemostasis in a swine model of splenic hemorrhage.

OBJECTIVE To compare the hemostatic capabilities of poly-Nacetylglucosamine (p-GlcNAc) with three currently available products: Actifoam, Surgicel, and Bolheal fibrin glue. This study was conducted in a controlled animal model, with monitoring of hematologic parameters over the course of the study. Two series were conducted, one in unheparinized animals comparing Bolheal fibrin sealant, Actifoam (absorbable collagen, AC), and Surgicel (ORC) with p-GlcNAc, and the second in systemically heparinized animals comparing p-GlcNAc with AC. METHODS This study was performed in immature female Yorkshire White swine. Splenic lacerations controlled for length and depth of wound were used as sources of bleeding, with one material used per wound to assess hemostatic effectiveness. A total of 97 wounds in 12 animals were created for the study, 74 wounds in unheparinized animals, and 23 wounds in the heparinized animals. In the heparinized animals, hemostatic efficacy was judged by number of applications needed to achieve complete hemostasis. In the unheparinized animals, hemostatic efficacy was judged by length of time required to achieve complete hemostasis (p-GlcNAc vs. fibrin sealant) or the number of applications needed to achieve complete hemostasis (p-GlcNAc vs. AC or ORC). RESULTS In systemically heparinized animals, p-GlcNAc demonstrated greater hemostatic efficacy (72.7 %) in one application than did the control material (0%), p < 0.01. In the unheparinized animals, p-GlcNAc took less time to achieve hemostasis (mean, 22.9 seconds) than fibrin sealant (mean, 172.9 seconds), p < 0.01. p-GlcNAc achieved hemostasis with a greater efficacy (79.2%) in one application than did the AC or ORC (16.7%), p < 0.01, whereas there was no difference in the efficacy of the control materials. CONCLUSION The results of the previous series in unheparinized animals demonstrated that p-GlcNAc in the form of a membrane is a more effective topical hemostatic agent than Bolheal fibrin glue, AC or ORC. The results in the anticoagulated animals similarly demonstrate that p-GlcNAc is a more effective topical hemostatic agent than the control material AC. These data indicate that p-GlcNAc is a promising hemostatic agent as evaluated in this model.

The Second SAGES/ASGE White Paper on natural orifice transluminal endoscopic surgery: 5 years of progress

) was first introduced,many physicians could envisage its potential as a lessinvasive and more cosmetic way to perform surgery. Thepotential for harm if NOTES was adopted too rapidlywas also readily apparent. To ensure the responsibledevelopment of these technologies and techniques and toencourage accurate and honest outcome assessment inhumans, the Society of American Gastrointestinal andEndoscopic Surgeons (SAGES) and the American Soci-ety for Gastrointestinal Endoscopy (ASGE) assembled aJoint Committee to serve as a working group to reviewthe issues involving NOTES. This working group sub-sequently published the ASGE/SAGES Working Groupon Natural Orifice Translumenal Endoscopic SurgeryWhite Paper [1, 2], which laid out the fundamentalchallenges to be addressed and outlined a pathwayfor the responsible development and evaluation ofNOTES. As part of this mission, the Joint Committeealso created an organization called Natural OrificeSurgery Consortium for Assessment and Research(NOSCAR). NOSCAR organized international meetings,developed and sought funding for a research agenda,fostered the translation of research findings into clinicaltrials, and began development of a human registry totrack the clinical adoption of NOTES.Summary of progress on issues outlinedby the original White PaperNOSCAR continues to be the primary vehicle foraddressing the issues laid out in the original White Paper(Table 1). By focusing research efforts on critical topicsand by revisiting the issues frequently (primarily by peerreview and at the annual meeting), substantial progress hasbeen achieved in addressing many of the challengesinherent in natural orifice surgery.

A pilot study evaluating the efficacy of a fully acetylated poly-N-acetyl glucosamine membrane formulation as a topical hemostatic agent ☆ ☆☆

BACKGROUND Topical hemostatic agents are frequently needed for control of intraoperative bleeding. Currently available topical products each have potential drawbacks, making a more effective topical hemostatic agent desirable. This study was performed to evaluate the effectiveness of a particular formulation of a newly available polysaccharide polymer, poly-N-acetyl glucosamine (p-GlcNAc), as a topical hemostatic agent for use in the operating room. Swine splenic incision and splenic capsular stripping hemorrhage models were initially used, with a subsequent pilot human study then performed. METHODS For the swine splenic incision model, anesthetized immature female Yorkshire white swine had a 3 x 8 mm incision created on the spleen. One of 3 agents (p-GlcNAc membrane, oxidized cellulose, or absorbable collagen) was sequentially applied to individual wounds and digitally compressed for 20 seconds. The wound was observed without pressure for 2 minutes. Up to 8 wounds per animal were created in 7 animals. For the swine splenic capsular stripping model a 2 x 2 cm area of capsular stripping on the surface of the spleen to a depth of 3 mm was created. Either p-GlcNAc membrane or oxidized cellulose was applied and digitally compressed for 60 seconds, followed by observation without pressure for 2 minutes. Six wounds per animal were created in 2 animals. If bleeding persisted in either model, a new cycle of compression was applied. These steps were repeated until hemostasis was achieved. No change in hemodynamics or coagulation factors was observed in either model. Subsequently, 10 consecutive patients undergoing elective small-bowel surgery were enrolled on pilot study. A 5 x 3 x 3 mm cruciate incision was created midway between the mesenteric and antimesenteric borders of the small bowel. Either p-GlcNAc membrane formulation or oxidized cellulose was applied (the sequence alternated per patient) with a 400-mg weight used for even, direct pressure. A second cruciate incision was then created on the contralateral side of the bowel to evaluate the second material. The number of applications required for hemostasis was assessed. Hemodynamics, small-bowel pathologic condition, and hematologic parameters were evaluated. RESULTS The p-GlcNAc membrane required fewer cycles of compression in the swine splenic incision model to achieve hemostasis than either absorbable collagen or oxidized cellulose (1.25 vs 2.58 and 3.41, respectively; P < .01) and caused more effective immediate cessation of bleeding (79% for p-GlcNAc vs 17% for both absorbable collagen and oxidized cellulose). With the more traumatic splenic capsular stripping model, p-GlcNAc required fewer cycles of compression to achieve hemostasis than oxidized cellulose (average, 2.5 versus 6.8 respectively; P < .01) and was able to achieve hemostasis with greater efficacy (50%) in 2 applications than did oxidized cellulose (0%; P < .01). When used in the human pilot study, p-GlcNAc membranes required fewer cycles of compression than oxidized cellulose (2.5 vs 5.4, respectively; P < .002), was able to stop bleeding with greater efficacy in 1 cycle of compression (50% vs 0%, respectively; P < .01), and ultimately accomplished hemostasis in 80% of the cases as opposed to 20%. CONCLUSIONS On the basis of its greater hemostatic efficacy as compared with collagen or oxidized cellulose-based products, p-GlcNAc holds promise as an effective topical hemostatic agent and deserves further evaluation.

The 3-D monitor and head-mounted display. A quantitative evaluation of advanced laparoscopic viewing technologies.

AbstractBackground: Stereoscopic (3-D) monitors and head-mounted displays have promised to facilitate laparoscopic surgery by increasing positional accuracy and decreasing operative time. To test this hypothesis, we evaluated the performance of subjects using these displays to perform standardized laparoscopic dexterity drills. Methods: Fifty laparoscopic novices worked within an abdominal cavity simulator using four videoscopic display configurations: (1) standard (2-D) monitor; (2) 3-D monitor; (3) 2-D head-mounted display; and (4) 3-D head-mounted display. Subjects repeated 3 standardized training exercises 2 times. We measured time to complete each drill and number of errors committed. Results: Mean total times to complete all 3 drills were 455, 459, 485, and 449 sec for configurations 1–4, respectively. Mean total errors committed numbered 11.3, 10.4, 12.3, and 10.8, respectively. Neither comparison reached statistical significance (p < 0.05). When 3-D configurations were compared to 2-D configurations overall, a small but statistically significant reduction in errors was noted for 1 drill only (4.3 vs 5.0, p= 0.018). Conclusions: Three-dimensional imaging slightly reduced the number of errors committed by laparoscopic novices during one test drill; this improvement, however, was not clinically significant. Neither the 3-D monitor nor the head-mounted display decreased task performance time. Widespread adoption of this technology awaits future improvement in display resolution and ease of use.

The hidden morbidity of pediatric trauma

In an attempt to characterize the emotional and behavioral consequences of severe multisystem injury on pediatric trauma patients and members of their immediate family, 54 former trauma patients and their families were studied at least 1 year after discharge. Of those in a home setting, 60% had residual personality changes. Physical and cognitive handicaps, often multiple, were present in 50%; and social, affective, and learning disabilities were present in like number. Only 20% of the 50 children are in a regular school class; the other 80% require special-needs education. An unexpected finding was the effect of the accident on uninjured siblings, 66% of whom were reported to have developed emotional disturbances, school problems and aggressive personality changes. Parents reported a worsening of their martial relationship in 32% of cases, and new social and financial problems in 60%. Twenty-one mothers who were previously employed have stopped working to care for their child and 20% of families have exhausted their savings or gone into debt. Although a variety of support services were available to these families, they reported little use of extended care facilities, visiting nurses, and counselors. There is a hidden morbidity in pediatric trauma. It manifests years after injury, not only as physical disability but also as changes in cognition, personality and behavior, and as family stress. Since success in pediatric trauma care is the restoration of the child as nearly as possible to his premorbid state, these data suggest that more attention and resources should be directed to the late consequences of multisystem injury in children.

How much feedback is necessary for learning to suture

BackgroundMany laparoscopic simulation training systems exist and have been shown to transfer learning of surgical skills to the operating room. The manner in which the training is structured to maximize learning has not been examined. There are many aspects to the acquisition of laparoscopic skills during training, one of which is the availability of knowledge of results (KR). Knowledge of results is information about the outcome of motor skill execution, usually provided to individuals at the end of the execution. The timing and nature of KR can affect how well people learn new motor skills. In addition, detailed instruction during learning can also affect skill acquisition. We studied the effects of KR and instruction on the learning curve of a suturing and knot-tying task. We hypothesized that KR was necessary for skill acquisition, and that detailed instruction would help trainees to learn to perform the task more correctly and reach a performance plateau earlier. In addition, the overall workload of a trainee during training would decrease as skills improved, especially when KR and coaching were provided.MethodsNine medical students with no previous laparoscopic surgical experience were randomly and evenly divided into three groups with different KR conditions: (1) no KR, (2) KR, (3) KR + instruction. Each subject attended a training session for 1 h each day, 6 days a week for 4 consecutive weeks. Performance measures such as task time, smoothness of instrument, and path length were recorded for each trial. Workload was assessed using the NASA-TLX questionnaire.ResultsWhile KR was necessary for learning to suture, continual instruction had limited additional benefits. However, KR + instruction did reduce subjects’ perceived overall workload.ConclusionsSurgical training could be carried out effectively with only knowledge of results. These results have implications for the staffing of surgical skills laboratories.

Common uses and cited complications of energy in surgery

BackgroundInstruments that apply energy to cut, coagulate, and dissect tissue with minimal bleeding facilitate surgery. The improper use of energy devices may increase patient morbidity and mortality. The current article reviews various energy sources in terms of their common uses and safe practices.MethodsFor the purpose of this review, a general search was conducted through NCBI, SpringerLink, and Google. Articles describing laparoscopic or minimally invasive surgeries using single or multiple energy sources are considered, as are articles comparing various commercial energy devices in laboratory settings. Keywords, such as laparoscopy, energy, laser, electrosurgery, monopolar, bipolar, harmonic, ultrasonic, cryosurgery, argon beam, laser, complications, and death were used in the search.ResultsA review of the literature shows that the performance of the energy devices depends upon the type of procedure. There is no consensus as to which device is optimal for a given procedure. The technical skill level of the surgeon and the knowledge about the devices are both important factors in deciding safe outcomes.ConclusionsAs new energy devices enter the market increases, surgeons should be aware of their indicated use in laparoscopic, endoscopic, and open surgery.

Can Surgeons Think and Operate with Haptics at the Same Time

Much effort has been devoted to incorporating haptic feedback into surgical simulators. However, the benefits of haptics for novice trainees in the early stages of learning are not clear. Presumably, novices have less spare attentional resources to attend to haptic cues while learning basic laparoscopic skills. The aim of this study was to determine whether novice surgeons have adequate cognitive resources to attend to haptic information. Thirty surgical residents and attendings performed a TransferPlace task in a simulator, with and without haptics. Cognitive loading was imposed using a mental arithmetic task. Subjects performed 10 trials (five with cognitive loading and five without) with and without haptics. Results showed that all subjects performed significantly slower (27%) when they were cognitively loaded than unloaded, but equally accurately in both cases, suggesting a speed–accuracy tradeoff. On average, subjects performed 36% faster and 97% more accurately with haptics than without, even while cognitively loaded. Haptic feedback can not only enhance performance, but also counter the effect of cognitive load. This effect is greater for more experienced surgeons than less experienced ones, indicating greater spare cognitive capacity in surgeons with more experience.