Biomedical subjects

Dirk R Larson

Publications and source records attributed to Dirk R Larson.

At least 37 records · Page 2Linked to original sources

PubMed2005

Meckel diverticulum: the Mayo Clinic experience with 1476 patients (1950-2002).

OBJECTIVE: Through a comprehensive review of the Mayo Clinic experience with patients who had Meckel diverticulum, we sought to determine which diverticula should be removed when discovered incidentally during abdominal surgery. SUMMARY BACKGROUND DATA: Meckel diverticula occur so infrequently that most articles have reported either small series or isolated cases. From these limited series, various conclusions have been reported without clearly indicating which incidental diverticula should be removed. METHODS: Medical records were reviewed of 1476 patients found to have a Meckel diverticulum during surgery from 1950 to 2002. Preoperative diagnosis; age; sex; date of surgery; and intraoperative, macroscopic, and microscopic findings from operative and pathology reports were recorded. Logistic regression analysis was used to determine which clinical or histologic features were associated with symptomatic Meckel diverticulum. The features analyzed were age; sex; length, base width, and ratio of length to base width of the diverticulum; and the presence of ectopic tissue or abnormal tissue (inflammation or enteroliths). RESULTS: Among the 1476 patients, 16% of the Meckel diverticula were symptomatic. The most common clinical presentation in adults was bleeding; in children, obstruction. Among patients with a symptomatic Meckel diverticulum, the male-female ratio was approximately 3:1. Clinical or histologic features most commonly associated with symptomatic Meckel diverticula were patient age younger than 50 years (odds ratio [OR], 3.5; 95% confidence interval [CI], 2.6-4.8; P < 0.001), male sex (OR, 1.8; 95% CI, 1.3-2.4; P < 0.001); diverticulum length greater than 2 cm (OR, 2.2; 95% CI, 1.1-4.4; P = 0.02), and the presence of histologically abnormal tissue (OR, 13.9; 95% CI, 9.9-19.6; P < 0.001). CONCLUSIONS: After analyzing our data, we neither support nor reject the recommendation that all Meckel diverticula found incidentally should be removed, although the procedure today has little risk. If a selective approach is taken, we recommend removing all incidental Meckel diverticula that have any of the 4 features most commonly associated with symptomatic Meckel diverticulum.

Adult↗

PubMed2005

Prognostic factors and predictors of outcome of immunoglobulin M monoclonal gammopathy of undetermined significance.

Monoclonal gammopathy of undetermined significance (MGUS) of the immunoglobulin M (IgM) class was diagnosed at our institution in 213 patients who resided in the 11 counties of southeastern Minnesota from 1960 to 1994. The median age at diagnosis was 74 years and the median concentration of serum M-protein was 1.2 g/dL. The 213 patients were monitored for 1567 person-years (median, 6.3 years), during which 71% died. During follow-up, non-Hodgkin's lymphoma (n = 17), Waldenstrom's macroglobulinemia (n = 6), primary amyloidosis (n = 3), and chronic lymphocytic leukemia (n = 3) developed in 29 patients (14%). The number of patients with progression to lymphoid neoplasms was 15.9 times that expected in the general population. The cumulative probabilities of progression to one of these disorders were 10% at 5 years, 18% at 10 years, and 24% at 15 years. The overall average risks for progression were approximately 1.5% per year. Rates of death resulting from other diseases (cardiovascular, cerebrovascular, etc.) were 31% at 5 years, 52% at 10 years, and 65% at 15 years. Multivariate analysis revealed that only the concentration of serum M-protein at diagnosis and the serum albumin value were independent predictors of progression. It was concluded that the patients with IgM MGUS should be followed indefinitely.

Adult↗

PubMed2005

Significant reduction in risk of falls and back pain in osteoporotic-kyphotic women through a Spinal Proprioceptive Extension Exercise Dynamic (SPEED) program.

OBJECTIVE: To determine the outcome of intervention with a spinal weighted kypho-orthosis (WKO) and a spinal proprioceptive extension exercise dynamic (SPEED) program on the risk of falls in ambulatory community-dwelling persons older than 60 years with osteoporosis-kyphosis at risk for falls. SUBJECTS AND METHODS: The study had 3 stages. At stage 1 (baseline), the 12 women in the kyphotic group were compared with 13 healthy controls to assess the risk of falls and balance disorder in the kyphotic group. At stage 2, the 12 kyphotic women began the SPEED program with a WKO (2 supervised sessions in an outpatient clinic and a 4-week, daily home-based training program). At stage 3, baseline and follow-up data of the kyphotic group were compared to determine the effect of intervention. RESULTS: At baseline, there were significant differences between the osteoporotic-kyphotic group and the control group in balance (P=.002), gait (P<.05), and strength (P<.05). After a 4-week intervention, comparison of the kyphotic group's baseline and follow-up results showed a significant change in balance (P=.003) and several gait parameters (P<.05). Mean back extensor strength improved significantly from baseline (144.0-46.5 N) to follow-up (198.6+/-55.2 N; P<.001). Lower extremity muscle strength was not changed significantly, except for improved left ankle plantar flexors (P=.02). Back pain decreased significantly (P=.001). CONCLUSION: Balance, gait, and risk of falls improved significantly with the 4-week SPEED program.

Accidental Falls↗

PubMed2004

Incidence of multiple myeloma in Olmsted County, Minnesota: Trend over 6 decades.

BACKGROUND: Previous studies have indicated that the incidence and mortality rates for multiple myeloma have increased in the United States. The authors reported on the incidence of multiple myeloma in Olmsted County, Minnesota, between 1991 and 2001 and on trends in multiple myeloma incidence over the last 56 years. METHODS: Using the files of the Mayo Clinic and the Olmsted Medical Center (Rochester, MN), the authors identified all residents of Olmsted County who had multiple myeloma, suspected myeloma, or a related disorder. Reports of all laboratory determinations, in addition to autopsy findings and death certificates, were obtained. The criteria for the diagnosis of multiple myeloma have not changed during the last 6 decades. RESULTS: All but 1 of the 47 residents with multiple myeloma first diagnosed between 1991 and 2001 were recognized antemortem. Fifty-five percent had a previous monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, or solitary plasmacytoma before multiple myeloma was diagnosed. From 1991 to 2001, the overall annual incidence rate, age-adjusted to the 2000 U.S. population, was 4.3 per 100,000 (95% confidence interval, 3.0-5.5 per 100,000). Poisson regression analysis showed no statistically significant trend in Olmsted County incidence rates over 56 years. In similar fashion, the authors adjusted multiple myeloma incidence rates from nine other studies worldwide for which adequate data were available and documented similar findings in each case, except for one study that included patients with smoldering multiple myeloma. CONCLUSIONS: The overall incidence of multiple myeloma in Olmsted County, Minnesota, has not changed in almost 6 decades. The apparent increase in incidence elsewhere is unexplained but probably is attributable to improvements in diagnostic techniques, particularly in older patients.

Adolescent↗

PubMed2004

Balance disorder and increased risk of falls in osteoporosis and kyphosis: significance of kyphotic posture and muscle strength.

This controlled trial was designed to investigate the influence of osteoporosis-related kyphosis (O-K) on falls. Twelve community-dwelling women with O-K (Cobb angle, 50-65 degrees measured from spine radiographs) and 13 healthy women serving as controls were enrolled. Mean age of the O-K group was 76 years (+/-5.1), height 158 cm (+/-5), and weight 61 kg (+/-7.9), and mean age of the control group was 71 years (+/-4.6), height 161 cm (+/-3.8), and weight 66 kg (+/-11.7). Quantitative isometric strength data were collected. Gait was monitored during unobstructed level walking and during stepping over an obstacle of four different heights randomly assigned (2.5%, 5%, 10%, and 15% of the subject's height). Balance was objectively assessed with computerized dynamic posturography consisting of the sensory organization test. Back extensor strength, grip strength, and all lower extremity muscle groups were significantly weaker in the O-K group than the control group (P <0.05), except right ankle plantar flexors (P =0.09). There was a significant difference in the anteroposterior and mediolateral displacements and velocities. The O-K subjects had less anteroposterior displacement, greater mediolateral displacement, reduced anteroposterior velocity, and increased mediolateral velocity compared with controls for all conditions of unobstructed and obstructed level walking. Obstacle height had a significant effect on all center-of-mass variables. The O-K subjects had significantly greater balance abnormalities on computerized dynamic posturography than the control group (P =0.002). Data show that thoracic hyperkyphosis on a background of reduced muscle strength plays an important role in increasing body sway, gait unsteadiness, and risk of falls in osteoporosis.

Accidental Falls↗

PubMed2004

Superior survival in primary systemic amyloidosis patients undergoing peripheral blood stem cell transplantation: a case-control study.

Primary systemic amyloidosis (AL) is a plasma cell dyscrasia resulting in multisystem failure and death. High-dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) has been associated with higher response rates and seemingly higher overall survival than standard chemotherapy. Selection bias, however, confounds interpretation of these results. We performed a case-match-control study comparing overall survival of 63 AL patients undergoing transplantation with 63 patients not undergoing transplantation. Matching criteria included age, sex, time to presentation, left ventricular ejection fraction, serum creatinine, septal thickness, nerve involvement, 24-hour urine protein, and serum alkaline phosphatase. According to design, there was no difference between the groups with respect to sex (57% males), age (median, 53 years), left ventricular ejection fraction (65%), number of patients with peripheral nerve involvement (17%), cardiac interventricular septal wall thickness (12 mm), serum creatinine (1.1 mg/dL [97.24 micromol/L]), and bone marrow plasmacytosis (8%). Sixty-six patients have died (16 cases and 50 controls). For PBSCT and control groups, respectively, the 1-, 2-, and 4-year overall survival rates are 89% and 71%; 81% and 55%; and 71% and 41%. Outside a randomized clinical trial, these results present the strongest data supporting the role of PBSCT in selected patients with AL.

Adult↗

PubMed2004

Double-blind, prospective, randomized study of warmed, humidified carbon dioxide insufflation vs standard carbon dioxide for patients undergoing laparoscopic cholecystectomy.

HYPOTHESIS: Patients undergoing warmed, humidified carbon dioxide (CO2) insufflation for laparoscopic cholecystectomy will (1) maintain a warmer intraoperative core temperature, (2) have their surgeon experience less fogging of the camera lens, and (3) have less postoperative pain than patients undergoing laparoscopic cholecystectomy with standard CO2 insufflation. DESIGN: A double-blind, prospective, randomized study comparing patients undergoing laparoscopic cholecystectomy with standard CO2 insufflation vs those receiving warmed, humidified CO2 (Insuflow Filter Heater Hydrator; Lexion Medical, St Paul, Minn) was performed. Main variables included patient core temperature, postoperative pain, analgesic requirements, and camera lens fogging. RESULTS: One hundred one blinded patients (69 women, 32 men) undergoing laparoscopic cholecystectomy were randomized into 2 groups-52 receiving standard CO2 insufflation (group A) and 49 receiving warmed, humidified CO2 (group B). Mean patient intraoperative core temperature change (group A decreased by 0.03 degrees C, group B increased by 0.29 degrees C, P =.01) and mean abdominal pain (Likert scale, 0-10) at 14 days postoperatively (group A, 1.0; group B, 0.3; P =.02) were different. Other variables (camera lens fogging, early postoperative pain, narcotic requirements, recovery room stay, and return to normal activities) between groups were similar. CONCLUSION: While patients undergoing laparoscopic cholecystectomy with warmed, humidified CO2 had several advantages that were statistically significant, no major clinically relevant differences between groups A and B were evident.

Carbon Dioxide↗

PubMed2004

Concurrent vs. staged colectomy and hepatectomy for primary colorectal cancer with synchronous hepatic metastases.

PURPOSE: Resection of hepatic metastases is the preferred treatment for selected patients after resection of primary colorectal carcinoma, but timing is controversial. This study was designed to compare outcomes of patients receiving concurrent resection of hepatic metastases and the primary colorectal tumor with those of patients receiving staged resection (within 6 months). METHODS: We retrospectively analyzed medical records (1986-1999) of 96 consecutive patients with synchronously recognized primary carcinoma and hepatic metastases who underwent concurrent (64 patients) or staged (32 patients) colonic and hepatic resections performed at our institution. RESULTS: Concurrent and staged groups were similar in demographics, tumor grade, stage, preoperative comorbidity (cardiac and respiratory), characteristics of hepatic metastases, and single vs. multiple lesions. No significant differences were observed between groups (concurrent vs. staged) in type of colon resection (P = 0.45) or hepatic resection (P = 0.09), overall operative duration (mean, 430 vs. 427 minutes; P = 0.39), blood loss (mean, 890 vs. 889 ml; P = 0.87), volume of blood products transfused (mean, 326 vs. 185 ml; P = 0.08), perioperative morbidity (53 vs. 41 percent; P = 0.25), disease-free survival from date of hepatectomy (median, 13 vs. 13 months; P = 0.53), or overall survival from date of hepatectomy (median, 27 vs. 34 months; P = 0.52). There was no operative mortality. Overall duration of hospitalization was significantly shorter for concurrent than for staged resection (mean, 11 vs. 22 days; P < or = 0.001). CONCLUSIONS: Concurrent colectomy and hepatectomy is safe and more efficient than staged resection and should be the procedure of choice for selected patients in medical centers with appropriate capacity and experience.

Aged↗

PubMed2004

Long-term survival after local excision for T1 carcinoma of the rectum.

PURPOSE: Many authors have reported high rates of local recurrence after local excision for early carcinoma of the rectum, which raises the question of whether oncologic resection gives better results. This study was designed to compare the long-term recurrence rate, long-term survival, and risk factors for T1 adenocarcinoma of the rectum treated with local excision or oncologic resection. METHODS: We identified 144 patients who had T1 sessile adenocarcinoma in the lower third or middle third of the rectum. Patients who received adjuvant therapy or who had pedunculated lesions were excluded. Data included age, gender, size of lesion, histologic type of carcinoma, grade, presence of lymphovascular invasion, and depth of invasion. Outcomes were defined as five-year and ten-year cumulative probabilities of local recurrence, distant metastasis, overall survival, and cancer-free survival. The mean follow-up was 9.2 years; median follow-up was 8.1 years. RESULTS: We compared 70 patients who underwent local excision with 74 patients who underwent oncologic resection. Among patients with lesions in the middle or lower third of the rectum, 1) the five-year and ten-year outcomes were significantly better for overall survival and cancer-free survival in the oncologic resection group, but there were no significant differences in local recurrence or distant metastasis; 2) the multivariate risk factors for long-term, cancer-free survival were invasion into the lower third of the submucosa, local excision, and older than aged 68 years; and 3) for lesions with invasion into the lower third of the submucosa, the oncologic resection group had lower rates of distant metastasis and better survival. Among patients with lesions in the lower third of the rectum, 1) the five-year and ten-year outcomes showed no significant differences in survival, local recurrence, or distant metastasis between the two groups; and 2) for lesions with invasion into the lower third of the submucosa, the oncologic resection group showed a trend of improved survival, which was not statistically significant, possibly because of low statistical power from the small sample size. CONCLUSIONS: Patients who undergo local excision or oncologic resection for T1 carcinoma in the lower two-thirds of the rectum have a high incidence of local recurrence and distant metastasis. To improve the cure rate, the rate of recurrence must decrease. A randomized, controlled study is needed to determine whether adjuvant therapy may be beneficial.

Adenocarcinoma↗

PubMed2004

The effect of ageing on function and quality of life in ileal pouch patients: a single cohort experience of 409 patients with chronic ulcerative colitis.

OBJECTIVE: To evaluate in what manner ageing affects functional outcome and quality of life (QoL) in patients with chronic ulcerative colitis (CUC) after ileal pouch-anal anastomosis (IPAA). SUMMARY BACKGROUND DATA: Short-term function and QoL after IPAA is good. However, patients are usually young, and little is known about the influence of time and ageing on long-term outcomes after IPAA. METHODS: Using a standardized questionnaire, functional outcome, QoL, and complications were assessed prospectively in a cohort of 409 patients followed annually for 15 years after IPAA. RESULTS: Follow-up was complete in the single cohort of 409 patients and functional and QoL outcomes summarized at 5, 10, and 15 years. Daytime stool frequency changed little (mean 6), while nighttime frequency increased from 1 stool to 2 stools. Incontinence for gas and stool increased from 1% to 10% during the day and from 2% to 24% at night over 15 years. The cumulative probability of pouchitis increased from 28% at 5 years to 38% at 10 years and to 47% at 15 years. Bowel obstruction and stricture were other principal long-term complications. At 15 years, 91% of patients had kept the same job. Work was not affected by the surgery in 83%, while social activities, sports, traveling, and sexual life all improved after surgery and did not deteriorate over time. CONCLUSIONS: These long-term results in a single cohort of 409 IPAA patients are unique and are likely a more accurate reflection of long-term outcome than has been previously reported. These data support the conclusion that IPAA is a durable operation for patients requiring proctocolectomy for CUC; functional and QoL outcomes are good, predictable, and stable for 15 years after operation.

Activities of Daily Living↗

PubMed2004

Presence of monoclonal free light chains in the serum predicts risk of progression in monoclonal gammopathy of undetermined significance.

We hypothesized that the presence of monoclonal free light chains (FLC) in the serum of patients with monoclonal gammopathy of undetermined significance (MGUS) is a marker of clonal evolution and a risk factor for progression. Forty-seven patients with MGUS and documented progression to myeloma or related malignancy were compared with 50 age- and gender-matched patients with MGUS and no evidence of progression after 5 or more years of follow-up. The presence of an abnormal kappa/lambda FLC ratio in the serum was associated with a higher risk of MGUS progression (relative risk 2.5; 95% confidence interval: 1.6-4.0; P < 0.001).

Biomarkers, Tumor↗

PubMed2004

Digital resistance and tendon strength during the first week after flexor digitorum profundus tendon repair in a canine model in vivo.

BACKGROUND: After flexor tendon repair, the strength of the repair and the resistance to digital motion are important considerations in deciding when to initiate postoperative rehabilitation. Our objective was to assess these factors in a short-term in vivo canine model of flexor tendon repair. METHODS: Forty-eight dogs were randomly allocated to four groups based on the duration of postoperative follow-up (one, three, five, or seven days). In each group, two flexor digitorum profundus tendons of one forepaw were exposed. One tendon (the repair tendon) was sharply transected and repaired with a modified Kessler suture, and the other one (the sham tendon) was simply exposed without laceration. The involved paw was immobilized until the animal was killed on the designated day. Three tendons from each dog, including the repair tendon, the sham tendon, and a control tendon from a corresponding normal digit on the contralateral side, were tested. RESULTS: The mean peak total digital resistance force in the repair group was lowest at five days (p < 0.01 compared with seven days; p > 0.05 compared with one and three days). The mean peak force needed to overcome the internal gliding resistance between the repaired tendon and sheath was significantly higher than that in both the sham and control groups at all time-points (p < 0.001); however, this value was also smallest at five days. There was no significant difference in suture strength at any time-point (p > 0.05). CONCLUSIONS: When we evaluated tendon-gliding and suture strength after flexor tendon repair, the least favorable ratio of repair strength to force needed to overcome the resistance to digital motion was noted on Day 7, whereas the best combination of tendon strength and low peak resistance force was noted on Day 5.

Animals↗

PubMed2004

Long-term follow-up of 241 patients with monoclonal gammopathy of undetermined significance: the original Mayo Clinic series 25 years later.

OBJECTIVE: To determine the long-term outcome of patients with monoclonal gammopathy of undetermined significance (MGUS). PATIENTS AND METHODS: We reviewed the medical records of 241 patients with MGUS who were examined at the Mayo Clinic in Rochester, Minn, between January 1, 1956, and December 31, 1970. RESULTS: Follow-up was 3579 person-years (median, 13.7 years; range, 0-39 years). Only 14 patients (6%) were alive and had no substantial increase of M protein at last follow-up; 138 patients (57%) died without evidence of multiple myeloma or a related disorder; a malignant lymphoplasma cell proliferative disorder developed in 64 patients (27%). The interval from diagnosis of MGUS to diagnosis of multiple myeloma or related disorder ranged from 1 to 32 years (median, 10.4 years). CONCLUSIONS: The median survival rate of study patients with MGUS was only slightly shorter than that of a comparable US population. Risk of progression of MGUS to lymphoplasma cell malignancy is indefinite and persists even after more than 30 years of follow-up, with no reliable predictors of malignant evolution.

Disease Progression↗

PubMed2004

Clinical course of patients with relapsed multiple myeloma.

OBJECTIVE: To study the clinical course of patients with multiple myeloma (MM) that relapses after initial therapy. PATIENTS AND METHODS: Patients with MM, seen at the Mayo Clinic in Rochester, Minn, between January 1, 1985, and December 31, 1998, were identified from a prospectively maintained database. Our study population consisted of 578 patients with newly diagnosed MM who were followed up and monitored throughout their clinical course at our institution. RESULTS: The median age of the 578 patients with MM was 65 years (range, 26-92 years); 228 patients (39%) were women. The median follow-up of 71 surviving patients was 55 months (range, 0-202 months). The overall survival (OS) for the 578 patients at 1, 2, and 5 years was 72%, 55%, and 22%, respectively; the median OS from initial therapy was 28.4 months. The median OS of 355 patients who experienced relapse after initial treatment was 17.1 months from initiation of the second therapy, and 84% died within 5 years. The duration of response decreased consistently with each successive regimen. Patients with a high plasma cell labeling index (> or = 1.0%), low platelet count (< 150 x 10(9)/L), high creatinine level (> or = 2.0 mg/dL), and low albumin level (< 3.0 g/dL) had a poorer prognosis. CONCLUSIONS: Our study revealed decreasing response duration with increasing number of salvage regimens, probably reflecting acquired drug resistance and an increasing proliferative rate of the myeloma cells. Patients who experienced relapse after initial treatment and received salvage therapy had a median survival of nearly 1.5 years. This must be remembered when making treatment decisions for these patients and must be factored in when assessing the efficacy of new therapies.

Adult↗

PubMed2004

Long-term survival after traumatic brain injury: a population-based analysis.

This population-based retrospective cohort study identified all Olmsted County, MN residents with any diagnosis indicative of potential traumatic brain injury (TBI) during the years 1985 to 2000. The complete community-based medical records of a random sample (n = 7,175) were reviewed to confirm and characterize the event, and to determine vital status through 2002. The review identified 1,448 confirmed incident cases; 164 (11%) were moderate to severe; 1,284 were mild. The estimated 30-day case fatality rate was 29% for moderate to severe cases and 0.2% for mild cases. Comparison of observed mortality over the full period of follow-up with that expected revealed a risk ratio (95% CI) of 5.29 (4.11-6.71) for moderate to severe cases and 1.33 (1.05-1.65) for mild cases. Proportional hazards modeling showed the adjusted hazard of all-cause mortality for moderate to severe cases relative to mild cases was 5.18 (3.65-7.3) within six months of the event and 1.04 (0.57-1.88) for the remaining follow-up period. This analysis indicates that persons who experience mild TBI exhibit a small but statistically significant reduction in long-term survival compared to the general population. The case fatality rate for persons with moderate to severe TBI is very high, but among six-month survivors, long-term survival is similar to that for persons with mild TBI.

Adult↗

PubMed2003

Long-term follow-up of IgM monoclonal gammopathy of undetermined significance.

Little effort has been made to quantitate adverse outcomes of monoclonal gammopathy of undetermined significance (MGUS) of the immunoglobulin M (IgM) class, which progresses to lymphoma or Waldenström macroglobulinemia, whereas IgA and IgG MGUS progress to multiple myeloma, primary amyloidosis (AL), or a related plasma cell disorder. From 1960 to 1994, IgM MGUS was diagnosed in 213 patients in southeastern Minnesota. The end point was progression to lymphoma or a related disorder, as assessed with the Kaplan-Meier method. The 213 patients were followed up for 1567 person-years (median, 6.3 years per patient). Lymphoma developed in 17 patients (relative risk [RR], 14.8), Waldenström macroglobulinemia in 6 (RR, 262), primary amyloidosis in 3 (RR, 16.3), and chronic lymphocytic leukemia in 3 (RR, 5.7). The relative risk of progression was 16-fold higher in the patients with IgM MGUS than in the white population of the Iowa Surveillance, Epidemiology, and End Results Program. Cumulative incidence of progression was 10% at 5 years, 18% at 10 years, and 24% at 15 years. On multivariate analysis, the serum monoclonal protein and serum albumin concentrations at diagnosis were the only risk factors for progression to lymphoma or a related disorder. Risk for progression to lymphoma or a related disorder at 10 years after the diagnosis of MGUS was 14% with an initial monoclonal protein concentration of 0.5 g/dL or less, 26% with 1.5 g/dL, 34% for 2.0 g/dL, and 41% for more than 2.5 g/dL.

Adult↗

PubMed2003

Surgical treatment of appendiceal mucocele.

HYPOTHESIS: Clinical presentation of appendiceal mucocele is related to malignancy and can influence surgical approach. DESIGN: Retrospective study. SETTING: Tertiary referral center. PATIENTS: All cases of primary appendiceal mucoceles (simple mucocele, cystadenoma, cystadenocarcinoma) diagnosed between 1976 and 2000 were reviewed. There were 135 patients, 74 of whom were female. Mean age at diagnosis was 59 years. Mean follow-up was more than 6 years. INTERVENTIONS: A total of 129 patients underwent surgery, consisting of appendectomy (22 patients), right hemicolectomy (25 patients), or more extensive procedures (82 patients). MAIN OUTCOME MEASURES: Clinical, diagnostic, and surgical variables were statistically compared with postoperative morbidity and mortality and the presence of malignancy. P<.05 was considered significant. RESULTS: The presence of symptoms was associated with malignancy (58% vs 15%, P<.001), particularly abdominal pain (56% vs 29%, P =.005) and weight loss (77% vs 31%, P =.002). Abdominal mass was also associated with malignancy (86% vs 25%, P<.001). Moreover, pseudomyxoma peritonei and mucocele extravasation were associated with malignancy (95% vs 13%, P<.001, and 83% vs 15%, P<.001, respectively). The lesion size was not associated with malignancy; however, cystadenomas were significantly larger than simple mucoceles (8.1 cm vs 4.1 cm, P<.001), and no cystadenoma was less than 2 cm in largest diameter. CONCLUSIONS: A number of clinical, diagnostic, and intraoperative findings are associated with malignant mucoceles. All mucoceles greater than 2 cm should be excised to remove premalignant lesions.

Appendiceal Neoplasms↗

PubMed2003

Biomechanical evaluation of posterior screw fixation in cadaveric cervical spines.

Sixteen fresh-frozen spines from cadavers (C4-T1) were randomized on the basis of dual energy xray absorptiometry analysis of bone mineral density. The specimens were subjected to physiologic loads (<or= 1.5 N-m) in a device that applied pure unconstrained, flexion and extension, lateral bending, and torsional moments. After a major injury, including a wide C6 laminectomy, bilateral capsulectomies, and 65% facetectomy at C6-C7, four constructs were applied to each specimen in a balanced sequence, and the stability tests were repeated. All the constructs were identical posterior cervical rods secured to the spine with lateral mass screws in C5 and pedicle screws in C7. The constructs differed only in the presence or absence of a transverse connector between the rods, presence or absence of lateral mass screws in C6, and unicortical or bicortical lateral mass screws. Insertional screw torque was higher in specimens with greater bone mineral density. Pedicle screws had greater torque than lateral mass screws. Posterior cervical spine rod fixation provided an equivalent stability by use of either unicortical or bicortical lateral mass screws. A transverse stabilizer between the rods reduces the number of lateral mass screws needed in posterior cervical spinal rod systems. Repeated stability tests, even when done with physiologic loads, may compromise the screw-bone interface. This effect is most pronounced in specimens that have low bone mineral density.

Adult↗