Retinitis pigmentosa-associated cystoid macular oedema: pathogenesis and avenues of intervention.

Hereditary retinal diseases are now the leading cause of blindness certification in the working age population (age 16-64 years) in England and Wales, of which retinitis pigmentosa (RP) is the most common disorder. RP may be complicated by cystoid macular oedema (CMO), causing a reduction of central vision. The underlying pathogenesis of RP-associated CMO (RP-CMO) remains uncertain, however, several mechanisms have been proposed, including: (1) breakdown of the blood-retinal barrier, (2) failure (or dysfunction) of the pumping mechanism in the retinal pigment epithelial, (3) Müller cell oedema and dysfunction, (4) antiretinal antibodies and (5) vitreous traction. There are limited data on efficacy of treatments for RP-CMO. Treatments attempted to date include oral and topical carbonic anhydrase inhibitors, oral, topical, intravitreal and periocular steroids, topical non-steroidal anti-inflammatory medications, photocoagulation, vitrectomy with internal limiting membrane peel, oral lutein and intravitreal antivascular endothelial growth factor injections. This review summarises the evidence supporting these treatment modalities. Successful management of RP-CMO should aim to improve both quality and quantity of vision in the short term and may also slow central vision loss over time.

Guided imagery: a significant advance in the care of patients undergoing elective colorectal surgery.

PURPOSE: Guided imagery uses the power of thought to influence psychologic and physiologic states. Some studies have shown that guided imagery can decrease anxiety, analgesic requirements, and length of stay for surgical patients. This study was designed to determine whether guided imagery in the perioperative period could improve the outcome of colorectal surgery patients. METHODS: We conducted a prospective, randomized trial of patients undergoing their first elective colorectal surgery at a tertiary care center. Patients were randomly assigned into one of two groups. Group 1 received standard perioperative care, and Group 2 listened to a guided imagery tape three days preoperatively; a music-only tape during induction, during surgery, and postoperatively in the recovery room; a guided imagery tape during each of the first six postoperative days. Both groups had postoperative patient-controlled analgesia. All patients rated their levels of pain and anxiety daily, on a linear analog scale of 0 to 100. Total narcotic consumption, time to first bowel movement, length of stay, and number of patients with complications were also recorded. RESULTS: Groups were similar in age and gender distribution, diagnoses, and surgery performed. Median baseline anxiety score was 75 in both groups. Before surgery, anxiety increased in the control group but decreased in the guided imagery group (median change, 30; P < 0.001). Postoperatively, median increase in the worst pain score was 72.5 for the control group and 42.5 for the imagery group (P < 0.001). Least pain was also significantly different (P < 0.001), with a median increase of 30 for controls and 12.5 for the imagery group. Total opioid requirements were significantly lower in the imagery group, with a median of 185 mg vs. 326 mg in the control group (P < 0.001). Time to first bowel movement was significantly less in the imagery group (median, 58 hours) than in the control group (median, 92 hours; P < 0.001). The number of patients experiencing postoperative complications (nausea, vomiting, pruritus, or ileus) did not differ in the two groups. CONCLUSION: Guided imagery significantly reduces postoperative anxiety, pain, and narcotic requirements of colorectal surgery and increases patient satisfaction. Guided imagery is a simple and low-cost adjunct in the care of patients undergoing elective colorectal surgery.

Dentinal tubule occlusion and root hypersensitivity.

Previous studies have established that root sensitivity is due in part to open dentinal tubules at the root surface. The purpose of this study was to longitudinally evaluate the occlusion of dentinal tubules by various clinical procedures including scaling and root planing and the application of potassium oxalate. A model was developed to evaluate dentinal surfaces in vivo. Six 2 mm x 3 mm sections were taken from the roots of extracted teeth immediately below the CEJ. One half of the treated dentin samples from each donor was incorporated into the removable denture worn by the donor and the other half served as baseline. The dentin samples were evaluated at 1 week by scanning electron microscopy. At day zero no open tubules were observed in any of the samples due to the presence of a smear layer or oxalate crystals. Evaluation of root planed samples revealed that by 7 days the tubules had re-opened. The samples which had been treated with potassium oxalate showed few oxalate crystals by 7 days revealing open tubules. Control samples were etched with EDTA and evaluated in the same manner. Although the number of tubules did not significantly change in the EDTA etched control samples, the diameter of the tubules dramatically decreased by 4 weeks. It can be concluded that the creation of a smear layer or application of oxalates to occlude dentinal tubules to reduce sensitivity are relatively short-lived. These procedures may provide patient comfort prior to natural occlusion of the tubules.