The aim of this study is to examine 2 types of differential misclassification of exposure in case-crossover studies. The first is the outcome-dependent misclassification of exposure, meaning that if an event has occurred, it could affect the reporting of exposure. The second is differential misclassification of exposure as a result of fading memory over time, which arises if the length of the recall period for case and control windows differs. We use empirical data from a case-crossover study of triggers of attacks in Ménière's disease. The study applied the matched-pair interval control window sampling approach. We examined misclassification in relation to 2 different types of exposures: emotional stress and salty food intake. The study covered repeated events reported by the same patients and involved the sampling of many control windows. Because some of these windows were related to case events and some unrelated, we were able to conduct both case-crossover and control-crossover analyses. Although this group of Ménière patients are well aware of their disease, and many of them have definite ideas regarding what triggers attacks, neither outcome-dependent misclassification nor differential misclassification of exposure resulting from fading memory over time seemed to be a major problem.
The objective of this study was to examine factors affecting morbidity after tonsillectomy in children. Data from the National Tonsil Surgery Register in Sweden on 18,712 patients who underwent tonsillectomy with or without simultaneous adenoidectomy between 1 and 18 years of age were analysed. This register includes data on sex, gender, surgical indication, and the surgical and haemostasis techniques used for each patient, as well as patient-reported outcomes for haemorrhage, analgesic use and antibiotic use. Comparison of patients who underwent surgery for infection versus upper airway obstruction revealed a significant increase in haemorrhage complications in the infection group. However, no significant difference remained after the adjustments for confounders in multivariable regression analysis. Instead, the increased risk among patients who underwent surgery for infection was mainly attributable to the use of bipolar diathermy and increased patient age. Patients who received surgery for infection reported more days of analgesic use, as well as more unplanned contacts with a health care service provider due to pain, compared with those who underwent surgery for upper airway obstruction. These results remained significant in multivariate analysis. The use of bipolar diathermy for haemostasis resulted in an increased risk, while the use of cold steel surgical instruments, a younger patient age and female sex led to a decreased risk. The surgical and haemostasis techniques used are the most important factors that affect morbidity after tonsillectomy in the paediatric age group. The choice of surgical techniques is of utmost importance for decreasing morbidity in these patients.
Tonsillotomy (TT) is now used more often than tonsillectomy (TE) for tonsil obstructive symptoms in Sweden. Both TE and TT give high patient satisfaction although TT results in fewer postoperative bleedings and shorter time when analgesics are needed. The objective of this study is to analyze the current prevalence of different tonsil surgery procedures, the rates of early and late bleeding and other complications. Data from the National Tonsil Surgery Register in Sweden were analyzed. Patients 1-15 years operated for symptoms due to tonsil hypertrophy were included. Surgical procedure, technique and bleedings during hospital stay were registered. Thirty days after surgery, unplanned contacts due to bleeding, infection or pain were reported as were symptom relief after 6 months. 24,083 patients were registered. Of the 10,826 children 1-15 years operated for obstructive symptoms, 64 % were TT or TT+A, and 34 % TE, TE+A. 69 % answered the 30-day questionnaire and 50 % the 6 months. Bleeding in hospital occurred in 1.38 %, late bleedings in 2.06 %: 3.7 % after TE+A, 0.8 % after TT+A. Differences in readmissions due to bleeding, number of days using analgesics, health care contacts due to pain and nosocomial infections were significant between TT and TE, but not differences with regard to symptom relief after 6 months.
The Swedish National Registry for Tonsil Surgery has been operational since 1997. All ENT clinics in Sweden are encouraged to submit data for all patients scheduled for tonsil surgery. Preoperatively, age, gender and indication are recorded. Postoperatively, method (tonsillectomy or tonsillotomy), technique, and perioperative complications are recorded. Postoperative bleedings, pain, infections, and symptom relief are assessed through questionnaires. An earlier report from this registry showed that tonsillotomy had become more common than tonsillectomy in children with tonsil-related upper airway obstruction. The aim of this study was to categorize which instruments were used for tonsillotomy in Sweden and to compare their outcome and complication rate. All children 2-18 years, reported to the registry from March 2009 until September 2012, who underwent tonsillotomy on the indication upper airway obstruction, were included in the study. 1,676 patients were identified. In 1,602 cases (96%), a radiofrequency instrument was used. The postoperative bleeding rate was low (1.2%) and the degree of symptom relief was high (95.1%). Three different radiofrequency instruments (ArthroCare Coblation(®), Ellman Surgitron(®), and Sutter CURIS(®)) were used in 96% of the patients. There were no significant differences in the number of postoperative bleedings, postoperative infections or symptom relief between the instruments. The only difference found was in the number of days on analgesics, where more days were registered after use of Coblation(®). In Sweden, radiofrequency tonsillotomy is the dominant surgical technique used for tonsil hypertrophy causing upper airway obstruction in children. There are no significant differences in outcome between the different radiofrequency instruments except for number of days on analgesics after surgery.
To analyze the incidence of primary bleeding following tonsil surgery and to evaluate risk factors.
Register study of the results from the National Tonsil Surgery Register in Sweden covering the period 1997 to 2008 and 54,696 operations.
Data were collected by means of three questionnaires, two filled in by professionals and one 6 months postoperatively by the patient/parent.
A total of 719 patients experienced primary postoperative bleeding during the hospital stay (1.3%). A number of independent factors were correlated with decreased risk of post-tonsillectomy hemorrhage: younger age (P
Tonsillectomy (TE) is one of the most frequently performed ENT surgical procedures. Post-tonsillectomy haemorrhage (PTH) is a potentially life-threatening complication of TE. The National Tonsil Surgery Register in Sweden (NTSRS) has revealed wide variations in PTH rates among Swedish ENT centres. In 2013, the steering committee of the NTSRS, therefore, initiated a quality improvement project (QIP) to decrease the PTH incidence. The aim of the present study was to describe and evaluate the multicentre QIP initiated to decrease PTH rates.
Six ENT centres, all with PTH rates above the Swedish average, participated in the 7-month quality improvement project. Each centre developed improvement plans describing the intended changes in clinical practice. The project's primary outcome variable was the PTH rate. Process indicators, such as surgical technique, were also documented. Data from the QIP centres were compared with a control group of 15 surgical centres in Sweden with similarly high PTH rates. Data from both groups for the 12 months prior to the start of the QIP were compared with data for the 12 months after the QIP.
The QIP centres reduced the PTH rate from 12.7 to 7.1% from pre-QIP to follow-up; in the control group, the PTH rate remained unchanged. The QIP centres also exhibited positive changes in related key process indicators, i.e., increasing the use of cold techniques for dissection and haemostasis.
The rates of PTH can be reduced with a QIP. A national quality register can be used not only to identify areas for improvement but also to evaluate the impact of subsequent improvement efforts and thereby guide professional development and enhance patient outcomes.
Tonsil surgery to address upper airway obstruction in children can be performed either as a tonsillectomy (TE) or as a tonsillotomy/intracapsular/partial tonsillectomy (TT). The advantage of TT is a decreased risk of postoperative morbidity. The disadvantage is the risk of tonsil regrowth with recurrence of symptoms and/or problems with future tonsil infections, which may demand a reoperation of the tonsils. The aim of this study is to compare the risk of reoperation of the tonsils following TE and TT in children with tonsil-related upper airway obstruction. This is a retrospective register-based cohort study of the Swedish National Patient Register. All children aged 1-12 years who underwent TE or TT from 2007 to 2012 for the main indication of upper airway obstruction were included in the study. The unique Personal Identity numbers were used to follow patients over time in the register and identify additional tonsil surgery. A total of 27,535 patients were included in the study, contributing 76,054 person-years of follow-up. A total of 684 patients (2.5 %) underwent a second tonsil surgery during follow-up. The incidences of reoperation were 1.94 per 1000 person-years in the TE group and 16.34 per 1000 person-years in the TT group. The risk for reoperation was seven times higher (HR 7.16) after TT compared to TE. Younger age was significantly associated with reoperation for both TE and TT and the difference in risk between TE and TT gradually decreased with time. The most common indication for reoperation after both TE and TT was "Upper airway obstruction".
Patients operated with tonsillar surgery report a high degree of symptom relief 6 months after surgery.
The purpose of this study was to analyze symptom relief 6 months after tonsil surgery in relation to age, indication, surgical procedure, primary bleeding and unplanned postoperative visits. The National Tonsil Surgery Register in Sweden offers data from 54,696 patients registered during 1997-2008.
This was a prospective assessment by questionnaire. Data were collected using three questionnaires, two completed by professionals and one 6 months postoperatively by the parents/patients.
Among 54,696 patients, the most common surgical indications were obstruction (49.7%), followed by recurrent tonsillitis (35.2%). Symptom relief 6 months after surgery was high in all indication groups (>92%), and highest for patients operated on the indication peritonsillitis (>98%). The indications obstruction, recurrent tonsillitis or chronic tonsillitis reported a high degree (>96%) of symptom relief. Of the patients who underwent tonsillectomy with adenoidectomy, 97.5% were symptom-free compared to 96% of patients who had tonsillectomy alone and 96.1% who underwent tonsillotomy (p