Reoperation as a quality indicator in colorectal surgery: a population-based analysis

OBJECTIVE: To describe unplanned procedures following colorectal cancer surgery that might be used as intermediate outcome measures, and to determine their association with mortality and length of stay. SUMMARY BACKGROUND: Variation in the quality of surgical care, especially for common illnesses like colorectal cancer, has received increasing attention. Nonfatal complications resulting in procedural interventions are likely to play a role in poor outcomes but have not been well explored. METHODS: Cohort analysis of 26,638 stage I to III colorectal cancer patients in the 1992 to 1996 SEER-Medicare database. Independent variables: sociodemographics, tumor characteristics, comorbidity, and acuity. Primary outcome: postoperative procedural intervention. Analysis: Logistic regression identified patient characteristics predicting postoperative procedures and the adjusted risk of 30-day mortality and prolonged hospitalization among patients with postoperative procedures. RESULTS: A total of 5.8% of patients required postoperative intervention. Patient characteristics had little impact on the frequency of postoperative procedures, except for acute medical conditions, including bowel perforation (relative risk [RR] = 3.0, 95% confidence interval [CI] = 2.5-3.6), obstruction (RR = 1.6; 95% CI = 1.4-1.8), and emergent admission (RR = 1.3; 95% CI = 1.1-1.4). After a postoperative procedure, patients were more likely to experience early mortality (RR = 2.4; 95% CI = 2.1-2.9) and prolonged hospitalization (RR = 2.2; 95% CI = 2.1-2.4). The most common interventions were performed for abdominal infection (31.7%; RR mortality = 2.9; 95% CI = 2.3-3.7), wound complications (21.1%; RR mortality = 0.7; 95% CI = 0.4-1.3), and organ injury (18.7%; RR mortality = 1.6; 95% CI = 1.1-2.3). CONCLUSIONS: Postoperative complications requiring additional procedures among colorectal cancer patients correlate with established measures of surgical quality. Prospective tracking of postoperative procedures as complication markers may facilitate outcome studies and quality improvement programs.     

Postprocedural microembolic events following carotid surgery and carotid angioplasty and stenting

OBJECTIVE: The relative safety of percutaneous carotid interventions remains controversial. Few studies have used diffusion-weighted magnetic resonance imaging (DW-MRI) to evaluate the safety of these interventions. We compared the incidence and distribution of cerebral microembolic events after carotid angioplasty and stenting (CAS) with distal protection to standard open carotid endarterectomy (CEA) using DW-MRI. METHODS: From November 2004 through August 2006, 69 carotid interventions (27 CAS, and 42 CEA) were performed in 68 males at a single institution. Pre- and postprocedure DW-MRI exams were obtained on each patient undergoing CAS and the 20 most recent CEA operations. These 46 patients (47 procedures as one patient underwent bilateral CEAs in a staged fashion) constitute our study sample, and the hospital records of these patients (27 CAS and 20 CEA) were retrospectively reviewed. The incidence and location of acute, postprocedural microemboli were determined using DW-MRIs and assessed independently by two neuroradiologists without knowledge of the subjects' specific procedure. RESULTS: Nineteen CAS patients (70%, 95% confidence interval [CI]: 42%-81%) demonstrated evidence of postoperative, acute, cerebral microemboli by DW-MRI vs none of the CEA patients (0%, 95% CI: 0%-17%) (P < .0001). Of the 19 CAS patients with postoperative emboli, nine (47%) were ipsilateral to the index carotid lesion, three (16%) contralateral, and seven (36%) bilateral. The median number of ipsilateral microemboli identified in the CAS group was 1 (interquartile ranges [IQR]: 0-2, range 0-21). The median number of contralateral microemboli identified in the CAS group was 0 (IQR: 0-1, range 0-5). Three (11%) CAS patients experienced temporary neurologic sequelae lasting less than 36 hours. These patients suffered 12 (six ipsilateral and six contralateral), 20 (19 ipsilateral and one contralateral), and zero microemboli, respectively. By univariate analysis, performing an arch angiogram prior to CAS was associated with a higher risk of microemboli (median microemboli 5 vs none, P =.04) CONCLUSIONS: Although our early experience suggests that CAS may be performed safely (no permanent neurologic deficits following 27 consecutive procedures), cerebral microembolic events occurred in over two-thirds of the procedures despite the uniform use of distal protection. Open carotid surgery in this series seems to offer a lower risk of periprocedural microembolic events detected by DW-MRI.     

Biomechanical evaluation of locking plate radial shaft fixation: unicortical locking fixation versus mixed bicortical and unicortical fixation in a sawbone model

PURPOSE: Compression plating is a commonly accepted technique for treating diaphyseal forearm fractures. The purpose of this study was to evaluate the stabilizing effects of two hybrid fixations that replace the end screws of a locked unicortical fixation with bicortical (locked or unlocked) screws and to compare these hybrid fixations to an unlocked bicortical fixation. METHODS: Sixteen composite radius sawbones were equally divided into 4 groups. We performed a midshaft osteotomy and plate fixation on the volar surface with 1 of 4 different constructs: 3 unlocked bicortical screws on each side (unlocked bicortical), 3 locked unicortical screws on each side (locked unicortical), or with 2 unicortical locked screws near the fracture and 1 bicortical unlocked (unlocked hybrid) or locked (locked hybrid) screw distant from the fracture on each end (LCP system, Synthes USA, Paoli, PA). Specimens were tested in nondestructive 4-point bending and torsion on a servo-hydraulic material testing system. The construct stiffness was obtained from the linear portion of the load-displacement curves after 3 cycles of preconditioning. The results from all groups were compared using analysis of variance and post hoc Bonferroni tests. RESULTS: Under torsional loads, replacing the end screws of a locked unicortical configuration with bicortical screws significantly improved the construct stiffness: 57.6% increase for the locked screws and 51.6% increase for the unlocked. In anteroposterior (AP) bending, the highest improvement over the locked unicortical configuration came from the locked hybrid constructs (42.9% increase). When compared with the unlocked bicortical configuration, both hybrid constructs provide equivalent stability in torsion but superior stability in AP bending. CONCLUSIONS: Replacing a single set of unicortical locked screws with locked or unlocked bicortical screws distant from the fracture site improves torsional stability of the construct by more than 50%, giving stability equal to standard unlocked plating. The hybrid fixation, however, with locked bicortical end screws has the best stability in AP bending.     

Decreased incidence of acute rejection in adolescent kidney transplant recipients using antithymocyte induction and triple immunosuppression

BACKGROUND: Acute rejection is a frequent event in pediatric renal transplantation; it can diminish allograft function and affect long-term outcome. Recent data from the North American Pediatric Renal Transplant Cooperative Study indicates that the rate of acute rejection remains high despite current immunosuppressive regimens. METHODS: In this retrospective series, we examined 37 pediatric renal transplant recipients who received induction doses of antithymocyte globulin combined with maintenance immunotherapy using tacrolimus, mycophenolate mofetil, and prednisone. The postoperative course was reviewed for initial and total hospital stay, number of rehospitalizations, evidence of posttransplant complications, graft fibrosis, and overall patient and graft survival. RESULTS: Three episodes of acute rejection (8.1%) were recorded in the first year posttransplant. The median initial hospital stay for patients receiving a kidney transplant was 8 days. Patient and graft survival were 100% and 91.9% at 1 year, respectively. The incidence of viral infection (cytomegalovirus, BK virus, and Epstein-Barr virus) and posttransplant lymphoproliferative disease remained low. Urinary tract infection and fluid and electrolyte complications were the main causes of posttransplant hospitalization. CONCLUSIONS: We conclude that induction with antithymocyte globulin and maintenance immunosuppression with tacrolimus, mycophenolate, and prednisone should be considered a valuable tool in the management of children undergoing renal transplantation.     

Diabetic complications associated with new-onset diabetes mellitus in renal transplant recipients

BACKGROUND: Data are scarce regarding the incidence and risk factors for complications of new-onset diabetes mellitus (NODM) in renal transplant patients. METHODS: United States Renal Data System (USRDS) data from primary renal transplant recipients during 1995-2001 who developed NODM was used to examine diabetic complications over the first three years posttransplant. Prognostic models were used to evaluate patient characteristics and treatment choices associated with risk of each class of complications. Propensity scores for choice of calcineurin inhibitor were included in multivariate analyses. RESULTS: The analysis included 21,489 patients, of whom 4,105 developed NODM by 3 years posttransplant. One or more NODM complications developed in 2,393 patients (58.3% of all patients with NODM), comprising ketoacidosis (334, 8.1%), hyperosmolarity (131, 3.2%), renal complications (1,286, 31.3%), ophthalmic complications (340, 8.3%), neurological complications (665, 16.2%), peripheral circulatory disorders (170, 4.1%) and hypoglycemia/shock (301, 7.3%). Complications developed within a mean of 500 to 600 days from diagnosis of NODM. Multivariate analysis showed that increased recipient age, higher body mass index, African-American race, hepatitis C infection, hypertension as cause of end-stage renal disease, cold ischemia >or=30 hours, and use of tacrolimus each increased risk of complications. CONCLUSION: NODM is associated with similar complications to those seen in the general population, but these appear to develop at an accelerated rate. Obesity and use of tacrolimus are the only modifiable factors that appear to affect risk of NODM or its complications.     

The fate of lower extremities with failed free flaps: a single institution's experience over 25 years

BACKGROUND: Lower-extremity reconstruction with microvascular free flap coverage is often the only option for limb salvage. Flap failure rates, however, continue to have higher complication rates than those to other anatomic sites; a significant number of flaps that fail result in amputation. This study retrospectively analyzed patients treated at a single institution who underwent attempted lower-extremity limb salvage with microsurgical techniques over a 25-year period. Of particular interest are the outcome data for patients who had initial free flap failure. PATIENTS AND METHODS: A prospectively maintained database was used to identify patients who satisfy criteria. Every patient who was treated with a microvascular free flap to their lower extremities was identified and included in this analysis. All records were reviewed from 1980 through 2004. Patients who had free flaps to the lower extremity fail after the initial operation were identified and selected for further analysis. RESULTS: Five hundred eighty-eight patients who underwent microsurgical reconstruction of lower extremity wounds had a failure rate of 8.5%. Trauma patients (83%) had a failure rate of 9%. On subset analysis, the failure rate for trauma patients decreased from 11% (1980-1992) to 3.7% (1993-2004). Of patients who had a failed free flap, 18% went on to limb amputation; the remainder was salvaged with secondary free flaps, local flaps, or skin grafting. CONCLUSION: This single institutional experience spanning 25 years represents the longest continual series of lower-extremity free flaps reported in the literature. The improved success rate seen in the second half of the study period is attributed to a more critical selection of free-flap candidates, improved understanding of the physiology surrounding acute trauma and a more sophisticated multidisciplinary team organization.     

Severity of scapholunate instability is related to joint anatomy and congruency

PURPOSE: To determine whether the bony architecture of the distal radius and proximal scaphoid have a role in stabilizing the scaphoid, and to determine whether a relationship between the bony geometry measurements and the amount of wrist constraint could be determined. METHODS: Eight cadaver wrists were tested in a wrist joint motion simulator. The level of scapholunate instability after sectioning the scapholunate interosseous, radioscaphocapitate, and the scaphotrapezium ligaments was determined and related to radiographic measurements of volar tilt, lateral tilt (ulnar tilt of the radioscaphoid fossa), the depth of the radioscaphoid fossa, and 6 radii of curvature measurements of the proximal scaphoid and distal radius. The force to dorsally dislocate the scaphoid out of the radioscaphoid fossa was computed. RESULTS: The radioscaphoid fossa and scaphoid curvatures were larger in those wrists that did not show gross instability after ligamentous sectioning in the wrist simulator. Similarly, those wrists with a deeper radioscaphoid fossa and greater volar tilt were also more stable. The force required to dislocate these wrists was greater than in those wrists that showed gross carpal instability. CONCLUSIONS: This study suggests that the bony anatomy of the radius and scaphoid have a role in stabilizing the carpus after ligament injury. The effect of ligament sectioning on producing carpal instability may be moderated by the bone geometry of the radiocarpal joint. This may explain why some people may have a tear of the scapholunate interosseous ligament but not present with clinical symptoms.     

Laparoscopic appendectomy is superior to open appendectomy in obese patients

BACKGROUND: There are minimal data comparing laparoscopic appendectomy (LA) with open appendectomy (OA) in obese patients. METHODS: We reviewed consecutive adult patients from 2003 to 2005 who underwent an appendectomy at a University-affiliated teaching hospital. Obesity was defined as a body mass index of 30 or greater. Outcome measures included length of stay, surgical times, intra-abdominal abscesses, wound infections, and hospital charges. RESULTS: There were 116 patients with a mean body mass index of 35. Eighty-five patients underwent LA, 12 were converted to open, 4 of 12 (31%) were perforated. Thirty-one patients underwent OA. Overall, 21 (18%) were perforated. Length of stay for LA was better, 3.4 days versus 5.5 days for OA (P = .02), and wound closure rate was better, 90% for LA versus 68% for OA (P < .01). Other outcome measures were equivalent. CONCLUSIONS: LA is associated with shorter lengths of stay, fewer open wounds, and equivalent hospital charges and intra-abdominal abscess rates; and should be considered the procedure of choice for obese patients with appendicitis.     

Construct validity of computer-assisted assessment: quantification of movement processes during a vascular anastomosis on a live porcine model

BACKGROUND: Movement processes for 2 different suturing techniques within a single surgical task were quantified. METHODS: Junior (postgraduate years 1-2) and senior residents (postgraduate year 3 and higher) were tested on their ability to perform a vascular anastomosis on a live porcine model 1 week after a guided practice session. Two phases of 2 suturing techniques (parachute and running) were identified, and performance was evaluated during each phase using computer hand motion analysis (CHMA) and expert-based measures. RESULTS: Senior residents were more efficient on all segments based on CHMA and expert-based ratings (P < .05). CHMA showed a significant improvement in junior resident performance during each phase of the procedure (warm-up effect). The change in task difficulty during transition from parachute to running sutures was identifiable using CHMA. CONCLUSIONS: Different suturing techniques are executed using the same general motor program although specific program parameters are adjusted to suit each technique. The findings support a novel form of construct validity the for surgical assessment device, the concept of transfer of skills, and the use of computer evaluations for the assessment of technical skills embedded within complex surgical tasks.     

Effect of tibial drill-guide angle on the mechanical environment at bone tunnel aperture after anatomic single-bundle anterior cruciate ligament reconstruction

Purpose

The tibial drill-guide angle in anterior cruciate ligament (ACL) reconstruction influences the tunnel placement and graft-tunnel force, and is potentially associated with post-operative tunnel widening. This study aimed to examine the effect of the drill-guide angle on the stress redistribution at the tibial tunnel aperture after anatomic single-bundle ACL reconstruction.

Methods

A validated finite element model of human knee joint was used. The tibial tunnel with drill-guide angle ranging from 30° to 75° was investigated. The post-operative stress redistribution in tibia under the compressive, valgus, rotational and complex loadings was analysed.

Results

Compressive loading played a leading role on the stress redistribution at intra-articular tibial tunnel aperture. After ACL reconstruction, stress concentration occurred in the anterior and posterior regions of tunnel aperture while stress reduction occurred in the lateral and posteromedial regions under the compressive loading. Stress redistribution was partially alleviated by using the drill-guide angle ranging from 55° to 65°.

Conclusions

The present study quantified the effect of bone tunnel drill-guide angle on the post-operative stress redistribution. This phenomenon potentially contributed to tunnel widening. A tunnel drill-guide angle ranging from 55° to 65° was proposed based on the biomechanical rationale. It could serve as a helpful surgical guide for ACL reconstruction.