Design of sEMG assembly to detect external anal sphincter activity: a proof of concept.

OBJECTIVE: Conditional trans-rectal stimulation of the pudendal nerve could provide a viable solution to treat hyperreflexive bladder in spinal cord injury. A set threshold of the amplitude estimate of the external anal sphincter surface electromyography (sEMG) may be used as the trigger signal. The efficacy of such a device should be tested in a large scale clinical trial. As such, a probe should remain in situ for several hours while patients attend to their daily routine; the recording electrodes should be designed to be large enough to maintain good contact while observing design constraints. The objective of this study was to arrive at a design for intra-anal sEMG recording electrodes for the subsequent clinical trials while deriving the possible recording and processing parameters. APPROACH: Having in mind existing solutions and based on theoretical and anatomical considerations, a set of four multi-electrode probes were designed and developed. These were tested in a healthy subject and the measured sEMG traces were recorded and appropriately processed. MAIN RESULTS: It was shown that while comparatively large electrodes record sEMG traces that are not sufficiently correlated with the external anal sphincter contractions, smaller electrodes may not maintain a stable electrode tissue contact. It was shown that 3 mm wide and 1 cm long electrodes with 5 mm inter-electrode spacing, in agreement with Nyquist sampling, placed 1 cm from the orifice may intra-anally record a sEMG trace sufficiently correlated with external anal sphincter activity. SIGNIFICANCE: The outcome of this study can be used in any biofeedback, treatment or diagnostic application where the activity of the external anal sphincter sEMG should be detected for an extended period of time.

CO2 laser of oral dysplasia: clinicopathological features of recurrence and malignant transformation.

The use of the CO(2) laser in the management of oral dysplastic lesions has become a more common practice. Very few studies have evaluated recurrence, residual disease malignant transformation, and overall outcome in patients undergoing such a procedure. In this prospective study, a total of 123 oral dysplastic lesions from 77 consecutive patients were treated with the CO(2) laser (resection and/or ablation). The average age was 58 ± 4.8 years. The patients' recovery was uneventful and no complications were reported. Comparisons with the clinical and histopathological features and rate of recurrence as well as malignant transformation were made. The patients were followed-up for a mean of 6.4 years, and biopsies taken in case of changes suggestive of malignant development. Homogenous leukoplakias were identified in 31 patients, non-homogenous leukoplakias in 34 patients, whereas 12 patients had erythroplakias. Ex- and life-long smokers formed 88.3% of the recruited patients. While people who currently smoke and drink formed 55.8% of the cohort. Erythroplakias were solely identified in heavy life-long smokers. The most common identified primary anatomical locations were the lateral border of tongue, floor of mouth, and buccal mucosa. Moderate dysplasia was identified in 42 patients while 18 patients had severe dysplasia. Laser resection margins in selected cases (68 patients) were clear in 53 and showed mild-moderate dysplasia in the involved margins. The rate of recurrence had no significant association with the location but the severity of epithelial dysplasia. The rate of first recurrence after laser surgery was approximately 19.5%. Malignant transformation was observed in eight patients (10.4%), in the tongue and the floor of mouth. Recurrence and malignant transformation was mainly identified in erythroplakias and non-homogenous leukoplakias. Laser resection/ablation is recommended for oral dysplasia to prevent not only recurrence and malignant transformation but also postoperative oral dysfunction encountered by other conventional modalities.

Interstitial PDT for vascular anomalies.

INTRODUCTION: Photodynamic therapy is a proven therapeutic modality in the management of variety of pathologies involving the human body. Our aim in this clinical study is to prospectively evaluate the outcome following interstitial photodynamic therapy for patients with vascular anomalies. Patients' reports on quality of life with clinical and radiological evaluation were the main end point parameters used to assess the outcome. MATERIALS AND METHODS: Forty-three patients were referred to the UCLH Head and Neck Centre for treatment of vascular anomalies of the head and neck, including: infantile and congenital haemangiomas, venous, lymphatic and arteriovenous malformations. After multidisciplinary discussion, all patients underwent interstitial photodynamic therapy under general anaesthesia, using 0.15 mg/kg mTHPC as the photosensitising agent. Following treatment, patients were followed-up for a mean of 21 months. RESULTS: Fifteen out of nineteen patients who presented with long-term pain reported improvement after treatment. Also, 7/8 reported significant reduction of bleeding related to their vascular anomaly. Improvement of swelling was reported by 28/35 patients; while reduction of infection episodes was evident in 8/11 patients and 31/36 reported reduction in the disfigurement caused by their pathology. Significant reduction of swallowing problems was reported in 9/12 patients, and breathing problems in 7/9 patients. Clinical assessment showed that half of the patients had 'good response' to the treatment. Moderate clinical response was reported by 13 (30.2%) patients. Radiological assessment comparing imaging 6-week post-PDT to the baseline showed moderate response in 11 (25.6%) patients and significant response in 15 (34.9%) patients. CONCLUSION: This study on 43 patients with vascular anomalies undergoing interstitial photodynamic therapy provided evidence that PDT is a successful modality in the management of these pathologies that are resistant to conventional modalities, with minimal side effects.

Photodynamic therapy: The minimally invasive surgical intervention for advanced and/or recurrent tongue base carcinoma.

INTRODUCTION: The management of tongue base carcinoma continues to be a major challenge in head and neck oncology. Our aim in this prospective study was to evaluate the outcome following ultrasound-guided interstitial photodynamic therapy (US-iPDT) of stage IV tongue base carcinoma patients. Patients' reports on quality of life with clinical and radiological evaluation were the main end point parameters used to assess the outcome. MATERIAL AND METHODS: Twenty-one consecutive patients referred to the UCLH Head and Neck Centre for treatment of advanced and/or recurrent tongue base cancer were included in this study. Two-thirds of the referred patients had not been offered further conventional therapeutic options apart from palliative treatment. It was decided, by the multidisciplinary team, that the only available option was to offer US-iPDT under general anesthesia, using mTHPC (Foscan®) as the photosensitizing agent. Following treatment, patients were followed-up for a mean of 36 months (min. 21, max. 45). RESULTS: Nine of the 11 patients who presented with breathing problems reported improvement after treatment. Also, 19 of the 21 patients reported improvement of swallowing. Improvement of speech was reported by 11 of 13 patients. Clinical assessment showed that more than half of the patients had "good response" to the treatment and about a third reported "moderate response." Radiological assessment comparing imaging 6-week post-PDT to the baseline showed stable pathology with no change in size in four patients, minimal response in seven patients, moderate response in six patients, and significant response in two patients. Eight patients died; four of which due to loco-regional disease; and two from distant tumor spread. Kaplan-Meir survival curve was generated from the survival and follow-up data. CONCLUSIONS: Photodynamic therapy is a successful palliative modality in the treatment of advanced and/or recurrent tongue base carcinoma.

Photodynamic therapy outcome for oral dysplasia.

INTRODUCTION: Photodynamic therapy (PDT) is a minimally invasive surgical intervention used in the management of tissue disorders. It can be applied before, or after, any of the conventional modalities, without compromising these treatments or being compromised itself. MATERIALS AND METHODS: In this prospective study, a total of 147 consecutive patients with oral potentially malignant disorders were treated with surface illumination PDT, using 5-ALA or mTHPC as the photosensitizer. The average age was 53 ± 8.9 years. The patients' recovery was uneventful and no complications reported. Comparisons with the clinical and histopathological features and rate of recurrence as well as malignant transformation were made. The patients were followed-up for a mean of 7.3 years. ANALYSIS AND RESULTS: Homogenous leukoplakias were identified in 55 patients, non-homogenous leukoplakias in 73 patients, whereas 19 patients had erythroplakias. Ex- and current lifelong smokers formed 84.4% of the recruited patients. While people who currently smoke and drink formed 38.1% (56 patients) of the cohort. Erythroplakias were mainly identified in heavy lifelong smokers. The most common identified primary anatomical locations were the lateral border of tongue, floor of mouth and retromolar area. Moderate dysplasia was identified in 33 patients while 63 patients had severe dysplasias; and 32 patients had a histopathological diagnosis of carcinoma in situ. The rate of recurrence in laser surgery was approximately 11.6%. Malignant transformation was observed in 11 patients (7.5%), in the tongue, floor of mouth and retromolar area. Recurrence and malignant transformation was mainly identified in erythroplakias and non-homogenous leukoplakias. The final outcome of the cohort showed that 11 (7.5%) suffered from progressive disease, 5 (3.4%) had stable disease, 12 (8.2%) were considered partially responsive to the therapy. Complete response was identified in 119/147 patients (81%). CONCLUSION: 5-ALA-PDT and/or mTHPC-PDT offer an effective alternative treatment for oral potentially malignant disorders.

Ultrasound-guided photodynamic therapy for deep seated pathologies: prospective study.

INTRODUCTION: Interstitial photodynamic therapy remains an attractive remedial option in minimally invasive surgery. Our aim in this prospective study was to evaluate the outcome following ultrasound-guided iPDT of deep-seated pathologies. Patients' reports on quality of life with clinical and radiological evaluation were the main end point parameters used to assess the outcome. MATERIALS AND METHODS: Sixty-eight patients were referred to the UCLH Head and Neck Centre for treatment of various deep-seated pathologies involving the head and neck region, upper and lower limbs. All patients underwent interstitial photodynamic therapy under general anaesthesia, using 0.15 mg/kg mTHPC as the photosensitising agent. Following treatment, patients were followed-up for a mean of 7 months. RESULTS: All three patients who presented with visual problems reported improvement after treatment. Also, 14/17 patients reported improvement of breathing. Improvement of swallowing was reported by 25/30 patients; while speaking improvement was evident in 16/22 patients and 33/40 reported reduction in the disfigurement caused by their pathology. All five patients with impeded limb function reported some degree of improvement. Clinical assessment showed that half of the patients had 'good response' to the treatment and a third reported 'moderate response' with two patients being free of disease. Radiological assessment comparing imaging 6-week post-PDT to the baseline showed stable pathology with no change in size in 13 patients, minimal response in 18 patients, moderate response in 23 patients and significant response in 11 patients. CONCLUSION: This study on 68 patients with deep-seated pathologies undergoing interstitial photodynamic therapy provided evidence that PDT can be the fourth modality in the management of tissue disease.

Head & neck optical diagnostics: vision of the future of surgery.

Review paper and Proceedings of the Inaugural Meeting of the Head and Neck Optical Diagnostics Society (HNODS) on March 14th 2009 at University College London. The aim of our research must be to provide breakthrough translational research which can be applied clinically in the immediate rather than the near future. We are fortunate that this is indeed a possibility and may fundamentally change current clinical and surgical practice to improve our patients' lives.

Management of deep-seated malformations with photodynamic therapy: a new guiding imaging modality.

Photodynamic therapy is an emerging technology and results from the interactions between a photosensitiser, oxygen and light. The delivery of light may either be by surface illumination or by interstitial application. We describe the first clinical application of ultrasound-guided interstitial photodynamic therapy (US-iPDT). A total of 23 treatments with meta-tetra-hydroxyphenyl chlorine (mTHPC) and ultrasound-guided interstitial photodynamic therapy were performed on 21 patients with various conditions at the Head & Neck Centre, University College London Hospital. The needles could be clearly identified during insertion in all 23 treatments, and it was possible to guide parallel needle insertions using ultrasound. Although the resolution of ultrasound is not as high as that of other imaging modalities [i.e. computed tomography (CT) and magnetic resonance imaging (MRI)] it was satisfactory in identifying the centre and the peripheries of the pathological lesions. Ultrasound is very easy to perform, non-invasive, relatively inexpensive, quick, convenient, non-ionising, suited to the imaging of soft tissues and does not cause any discomfort. Ultrasound can be used to guide 'real-time' photodynamic therapy in deep-seated tumours and other malformations and can augment the information from other imaging modalities without affecting the patient's treatment outcome.