Technical considerations in distraction osteogenesis.

Five cases are presented to exemplify technical difficulties and complications which may be encountered when performing distraction osteogenesis in the facial skeleton. The procedure should be performed under close supervision by the surgical and orthodontic colleagues. Errors in the choice of vector may be managed by earlier removal of the distractor and subsequent traction on the previously osteotomized segments using orthodontic appliances and principles. Multiple distractors may be inserted in the same jaw and bimaxillary procedures are possible, increasing the likelihood of encountering technical difficulties. Detailed planning and close follow-up, with early recognition and active management of the complications, may be useful in ensuring a successful outcome of this versatile procedure.

Follow-up of collagen crosslink excretion in patients with oral squamous cell carcinoma and analysis of tissue samples.

The presence of an oral squamous cell carcinoma (OSCC) may be associated with increased urinary excretion of the markers of collagen degradation, hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP). We investigated the possibility of these markers predicting the presence of active disease. Patients from a current study on HP and LP were included as follows: Group 1a (OSCC with confirmed mandibular bony infiltration, n=12), group 1b (group 1a patients >6 months after successful treatment), group 2a (OSCC without evidence of mandibular bone infiltration, n=8), group 2b (group 2a patients >6 months after successful treatment), group 3a (recurrent OSCC, n=8), group 3b (group 3a patients >6 weeks later, symptoms unchanged) and group 4 (control group, n=74). Tissue samples from tumour tissue and adjacent healthy mucosa were additionally investigated for HP and LP concentrations (n=8). The decrease in the urinary concentrations of HP and LP was statistically significant between groups 1a and 1b (P<0.001 for HP and LP), but not between groups 2a and 2b (P=0.07 for HP and LP), while values in groups 1b and 2b were within the normal range. When comparing groups 3a and 3b, a significant increase was observed for LP (P=0.050), but not HP (P=0.208). In conclusion, successful treatment of OSCC with bony involvement may be associated with a reduction of urinary HP and LP, whereas ongoing disease may result in an increase of LP. HP and LP may both be useful markers of tumour progression in patients with OSCC.

Collagen crosslink excretion and staging of oral cancer.

Lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) are collagen crosslink residues of which the urinary concentration reflects the level of connective-tissue turnover. HP is ubiquitous in tissue, whereas LP is specific for bone. The purpose of this investigation was to assess the sensitivity and specificity of an increased urinary concentration of both HP and LP in indicating infiltration of mandibular bone by an oral squamous cell carcinoma (OSCC) or recurrence of the disease after successful therapy. We investigated the history and urine levels in 116 adult patients, who were divided into the following groups. Group 1: patients with OSCC with bone infiltration (n=17); group 2: patients with confirmed OSCC (n=12) without evidence of bone infiltration; group 3: patients with recurrence of an OSCC (n=13); group 4: patients without clinical evidence of disease (n=74). The range and upper limit of normal values (HP(max) and LP(max)) were measured from the normal controls in group 4. Levels of LP and HP were measured by HPLC and fluorescence detection. There was a significant difference in the average urinary levels of LP and HP between groups 1-4 (P<0.001). The presence of mandibular bone infiltration could be detected with a sensitivity and specificity of 100% when comparing groups 1 and 2. Presence of tumour tissue could be detected with a sensitivity of 90%. In conclusion, a normal LP concentration in patients with an OSCC strongly suggests that bone invasion by the disease has not taken place. If both urinary HP and LP are elevated, disease recurrence is highly likely.

[Clinical pilot study of interstitial photodynamic therapy for treatment of advanced head and neck tumors]. / Klinische Pilotstudie zur interstitiellen photodynamischen Therapie für die Behandlung von fortgeschrittenen Kopf-Hals-Tumoren.

BACKGROUND: Photodynamic therapy is a new treatment modality which uses a photochemical reaction to destroy tumour tissue. To date this treatment has only been applied effectively to the surface of small, superficial tumours due to the limitations imposed by light penetration. With the use of fibres introduced into the substance of the tumour, more bulky lesions can be treated successfully. STUDY: We describe the first clinical use of such a treatment in the management and, specifically, the amelioration of advanced head and neck cancer. We describe our results in 12 patients, in 11 of whom we were able to improve quality of life. In one patient there was no observable effect. The side-effects were minimal. DISCUSSION: We suggest that interstitial photodynamic therapy may be of use in the palliative care of patients with advanced disease and bulky tumours. It may also be of use in benign, bulky tumors, but this point requires further study.

Optical biopsy systems for the diagnosis and monitoring of superficial cancer and precancer.

Histopathology is the gold standard in the diagnosis of cancer and dysplasia. Screening for the disease in high-risk populations(6,15) and choosing the correct site for biopsy have implications for the choice of follow-up intervals and therapy. Sully & Field(12) suggest that molecular genetic analysis, such as the polymerase chain reaction, for detecting progressive loss of heterozygosity, may be a more accurate predictor of the clinical course of oral cancer. This technique is now semi-automated and compares favourably with the time taken for histopathology (commonly 1-2 weeks). Recent developments suggest that the fluorescent and spectroscopic features may distinguish diseased from healthy tissue, and below follows an introduction for the clinician to this fascinating and complex field. It is possible to obtain a diagnosis in real-time and, with the appropriate use of photochemicals and image enhancement, it may be possible to treat and monitor the effects of treatment in real-time.