Craniocervical stabilization using Luque/Hartshill rectangles.

Untreated craniocervical instability is associated with a high morbidity and a significant mortality. Existing methods using bone grafts, interlaminar wires, or acrylic eventually produce stability but require prolonged periods of immobility and have a high failure rate. The ideal method of fixation should provide for permanent correction of deformity and relief of symptoms, with immediate stabilization, at a single procedure. Posterior fixation of the occiput to a stable part of the cervical spine with a molded metal rectangle held in place by interlaminar wires was used to accomplish this. We report 20 patients treated consecutively who have undergone craniocervical fusion by this method using Luque/Hartshill rectangles. Fourteen patients had preexisting atlantoaxial instability and 6 had cord compression, but would become unstable after decompression. All operations were performed under general anesthesia; 9 patients (40%) were awake for intubation/positioning, and 7 patients had a simultaneous decompression. Sixteen patients made an uncomplicated recovery and became mobile 3 days postoperatively. Symptomatic and neurological improvement occurred in 70% of all patients. Neurological complications occurred in 4 patients (20%), reflecting the serious nature of the condition; 2 patients (10%) showed no change. Scrutiny of their presentations and operations failed to identify avoidable risk factors, except faulty wiring techniques. In all patients, permanent stabilization was achieved immediately, facilitating early mobilization with a real chance of improvement, which indicates that the method merits wider application.

A low cost system for performing CT stereotaxic brain biopsy.

The cost of commercially available CT-compatible frames for stereotaxic brain biopsy has limited their availability in the U.K. Our adaptation to a pre-CT stereotaxic frame that had been in use at Atkinson Morley's Hospital for 12 years, and the availability of a GE 9800 CT scanner has allowed us to carry out accurate CT-directed stereotaxic biopsy at minimal cost. The system has the additional advantage of speed and ease of use in inexperienced neurosurgical hands. Biopsies in 100 patients have been performed by 12 different surgeons (80% by registrars) who mastered the technique without difficulty. The rates of permanent morbidity (4%) and mortality (2%) are low, the two mortalities occurring in patients with high grade astrocytomas. They compare very favourably with rates for freehand burr-hole biopsy, and our overall diagnostic success rate of 83% for the initial biopsies, rising to 90% as a result of re-biopsy in 10 of the patients, is similar to that achieved with much more costly commercial systems. Benign lesions were found in 7% of patients who would otherwise have been assumed to have malignant tumours, and this finding emphasises the value of achieving a histological diagnosis in every lesion of the brain.

Anaesthesia and cognitive functioning. Mental function in postoperative day patients at the time of their release.

Day care patients at Law Hospital, who had received either a general or a local anaesthetic in conjunction with minor surgery, were assessed by five tests of mental function before surgery and before discharge from hospital some hours after surgery. These patients did not perform differently from control patients, who were subjected to the same two testing sessions, without intervening surgery or anaesthesia. It was concluded that the day cases were quite capable of normal cognitive functioning at the time of their discharge and that the procedures followed by the hospital for the discharge of day cases are generally adequate.

Ventilator problems caused by humidity in the air supplied from simple compressors.

Relative humidity of air produced by simple compressors used to drive ventilators was measured at different working pressures. At normal working pressures, a relative humidity of 100% was found and condensation occurred, mainly at the high pressure air/oxygen mixer valve. This resulted in blockages and loss of accuracy which could have serious consequences for patients. It was concluded that simple compressors are unsuitable and that medical air must be used.

Urine output and fluid therapy during anaesthesia and surgery.

To try to determine whether fluid therapy during surgery should be on a large or a small scale 23 patients and six control subjects were studied. The control subjects were fasted and transfused with 2 litres of Ringer-lactate solution in one hour, the volume of urine output being measured at intervals for four hours. The patients were transfused similarly under varying conditions of anaesthesia and surgery. The characteristic urine output during abdominal hysterectomy followed a low, irregular pattern, and this occurred whether or not substantial amounts of fluid were transfused. In two patients anaesthesia and minimal trauma were associated with oliguria. An established diuresis was altered by anaesthesia and inhibited by surgery. These results indicate that excess Ringer-lactate solution administered during surgery may not be excreted and that overtransfusion could easily occur.