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Coming dissertations at MedFak

  • Sequelae after Facial Palsy : Clinical, Anatomical and Electrophysiological Studies Author: David Jensson Link: Publication date: 2019-11-11 08:21

    Background: Sequelae after peripheral facial palsy, which among others include synkinesis, non-functional smile and/or lower lip asymmetry, may be devastating for the patient. Bell’s palsy is the most common form of peripheral facial palsy. 

    Aim: The aim was to study a) frequency and potential predictive factors of synkinesis in Bell’s palsy b) new surgical treatment options after facial nerve injury c) coactivation between muscles innervated by the facial nerve and the most common donor nerves in smile reanimation d) anatomical features of the lower lip depressors. 

    Methods: I: Frequency, severity and early predictors of synkinesis development were studied in 829 Bell’s palsy patients. II and IV: Anatomical technical feasibility of intra-facial nerve transfers was analyzed. V: Anatomical features of lower lip depressor muscles were studied and a literature review for lower lip depressor myectomies was performed. III: Coactivation of muscles innervated by cranial nerves during voluntary facial movements was measured with electromyography. 

    Results: I: In Bell’s palsy, synkinesis frequency was 21.3% at 12-months and Sunnybrook composite score at one month was found to be a good predictor for synkinesis. II and IV: A tension-free oculo-zygomatic and platysma-marginal mandibular nerve transfer was anatomically feasible. Full recovery of the lower lip after platsysma-marginal mandibular nerve transfer was found in a clinical case. III: The masseter muscle had a narrower coactivation pattern compared to the tongue. Bite induced a strong coactivation in the zygomaticus major muscle. V: The width of the depressor labii inferioris was 20 ± 4 mm and the distance from the midline to the lateral muscle border was 32 ± 4 mm. For the depressor anguli oris muscle, the corresponding measurements were 14 ± 3 mm and 54 ± 4 mm. The mean recurrence rate after lower lip myectomy reported in the literature is 21%.  

    Conclusion: I: Synkinesis in Bell’s palsy was 21%. Sunnybrook composite score at one month is a good predictor for synkinesis. II: Oculo-zygomatic nerve transfer may be a suitable technique to reduce eye synkinesis and achieve a stronger smile. III: The narrow coactivation pattern in the masseter muscle may be advantageous for spontaneous smile development. IV: The platysma motor nerve transfer is a feasible procedure and can lead to full recovery in lower lip paralysis. V: Knowledge of the width of the depressor muscles is of importance to ensure complete resection in lower lip myectomy.

  • Dose painting : Can radiotherapy be improved with image driven dose-responses derived from retrospective radiotherapy data? Author: Eric Grönlund Link: Publication date: 2019-11-08 10:53

    The main aim of curative radiotherapy for cancer is to prescribe and deliver doses that eradicate the tumor and spare the normal healthy tissues. Radiotherapy is commonly performed by delivering a homogeneous radiation dose to the tumor. However, concern have been raised that functional imaging methods such as magnetic resonance imaging (MRI) and positron emission tomography (PET) can provide a basis for prescribing heterogeneous doses - higher doses in malignant regions of the tumor and less dose where the tumor is less malignant. This form of radiotherapy is called “dose painting” and has the aim of utilizing the radiant energy as efficiently as possible to increase the tumor control probability (TCP) and to reduce the risk for unwanted side effects of the neighboring normal tissues.

    In this project we have studied how dose painting prescriptions could be derived through retrospectively analyzing pre-RT image data and post-RT outcomes for two different patient groups: one diagnosed with head and neck cancer with pre-RT fluorodeoxyglucose (18F-FDG) PET image data; and one patient group diagnosed with prostate cancer with pre-RT Gleason score data that were constructed to be mapped from apparent diffusion coefficient (ADC) data acquired from MRI. The resulting dose painting prescriptions for each of these diagnoses indicated that the TCP could be increased without increasing the average dose to the tumor volumes as compared to homogeneous dose treatments. These TCP increases were more noticeable when the tumors were larger and more heterogeneous than for smaller and more homogeneous tumors.

    We have also studied the potential to realize TCP increases with dose painting in comparison to homogeneous dose treatments by optimizing clinically deliverable dose painting plans for both diagnoses, i.e. head and neck cancer and prostate cancer. These plans were optimized with minimax optimization that aimed to maximize a robust TCP increase by considering uncertainties of the patient geometry. These plan optimizations indicated that the TCP compared to homogeneous dose treatments was increasing and robust regarding uncertainties of the patient geometry.

  • Nasal obstruction – impact on insomnia symptoms and sleep-disordered breathing Author: Caroline Bengtsson Link: Publication date: 2019-11-07 10:07

    Background: Nasal obstruction is very common in the general population, but the role of nasal obstruction in sleep quality is not clear. Nasal obstruction is also prevalent in patients with obstructive sleep apnoea (OSA) and may contribute to poor adherence to continuous positive airway pressure (CPAP) treatment.

    Aims: To investigate the impact of subjective nasal obstruction, as a single symptom or as part of chronic rhinosinusitis (CRS), in both objective and subjective sleep quality, in three different population based cohorts. Another aim was to investigate the usefulness of the Sinonasal Outcome Test-22 (SNOT-22) and peak nasal inspiratory flow (PNIF) in the treatment of OSA patients.

    Methods and results: In paper I (the SHE-study), a community-based sample of 400 women were investigated with polysomnography and questions on sleep quality, daytime- and nasal symptoms. Women with nasal obstruction at night (n=30) had significantly higher prevalence of several night time symptoms and excessive daytime sleepiness (EDS), but the polysomnography was normal.

    In paper II (the GA2LEN study, n= 26, 647) and paper III (RHINE II and RHINE III studies, n= 5, 145) questionnaires on sleep quality, daytime- and nasal symptoms were used, and CRS was defined according to the epidemiological diagnostic criteria of the European Position Paper of Rhinosinusitis and Nasal Polyps (EPOS). In paper II, sleep problems were highly prevalent in CRS, and there was a dose-response relationship between the disease severity of CRS and sleep problems. The addition of persistent allergic rhinitis to CRS further increased the risk of sleep problems.

    In paper III, 2.7% of individuals without nasal symptoms at baseline had developed CRS at follow-up 10 years later. Strong associations between incident CRS and impaired sleep quality and EDS were found. Three insomnia symptoms at baseline increased the risk for CRS at follow-up.

    In paper IV, 197 OSA patients initiating CPAP treatment were investigated before starting CPAP and at the follow-up 3-4 weeks later. SNOT-22 scores were generally high among all OSA patients indicating a large sinonasal disease burden, and improved among those with CPAP adherence ≥ 4 hours/night. A low PNIF value increased the risk for poor CPAP adherence.

    Conclusions: Subjective nasal obstruction at night impairs subjective sleep quality in women, but does not affect objective sleep quality. CRS impairs subjective sleep quality, and insomnia symptoms may be a risk factor for CRS. SNOT-22 and PNIF may be useful tools in the treatment of OSA patients.