Degenerate-disc Infection Study with Contaminant Control: Discussion on the Research Methods.

OBJECTIVE: The role of bacterial infection in the causation of disc degeneration and its consequences is controversial. The current evidence is limited to underpowered studies, with the majority of such studies having only an internal contaminant arm, and only one study having a control arm with a non-degenerate disc population. The Degenerate-disc Infection Study with Contaminant Control (DISC) study includes a control arm and an internal contaminant control to resolve these shortcomings. METHODS: The study is designed as a case-control study: cases are patients undergoing surgery for degenerated disc pathology and controls are patients undergoing surgery for non-degenerate pathology, such as trauma, scoliosis or tumor cases. RESULTS: This study is part of a multi-centric trial involving six spine centers with 15 spine surgeons contributing. The DISC study methodology, rationale and controversies are presented here. The predominant issue is how to interpret contamination. We present our algorithm for the DISC study to address this. For disc samples that are positive concurrently with positive paraspinal tissue sample, the result will be interpreted as contamination. For positive disc samples with a negative paraspinal tissue culture result, the interpretation of this result will be infection. If cultures for both disc sample and paraspinal tissue sample are negative, then the result is interpreted as non-infected. If the disc culture is negative but paraspinal tissue culture is positive, then it is treated as a contaminant. CONCLUSIONS: Future large-scale studies are required with a good control arm, a contamination arm, and histopathological correlations.

Risk factors for surgical site infection in the patient with spinal injury.

STUDY DESIGN: A retrospective chart review of 1561 patients with spinal injury was conducted over a 4-year period. OBJECTIVES: To determine the rate of surgical site infection in the spinal trauma population, to compare infection rates after spinal operations for elective and traumatic indications, and to identify risk factors for postoperative wound infections in the traumatic subpopulation. SUMMARY OF BACKGROUND DATA: Surgical site infection after spinal operations is a dreaded complication. Risk factors have been investigated previously, but the subset of patients with acute traumatic spinal injury may be distinct. METHODS: The hospital's infection control program was used to identify surgical site infections after spinal operations, and infection rates were calculated. Data including patient characteristics, severity of injury indicators, surgical factors, and perioperative management factors were collected for the patients presenting with acute spinal injury over a 4-year period. RESULTS: Postoperative wound infections developed in 24 of 256 patients. This infection rate of 9.4% was significantly (P < 0.001) higher than for elective spinal operations during the same period (3.7%). Risk factors found to be independently significant included delay until operation, increased postoperative intensive care unit stay, single (neurosurgical or orthopedic) versus combined operative team. CONCLUSIONS: Risk factors for surgical site infection in the acute trauma setting are identified. Two surgical teams may be involved without causing a higher rate of infection.

Providencia stuartii: a search for its natural habitat.

A selective differential medium has been used to search for Providencia stuartii in sewage, sewage contaminated natural waters and the faeces and skin of a small population of healthy non-hospitalized males. Colonization of 12 male patients with long-term indwelling bladder catheters and the general environment of the spinal injury unit was also examined. Providencia stuartii was not isolated from the non-hospital samples, but colonization of the urine (two patients) faeces (five patients) and skin (eight patients) was observed. Apart from equipment that had been in contact with patients urine or skin there was no general contamination of the ward environment suggesting that colonized patients were the main reservoir of this multiply antibiotic-resistant nosocomial pathogen.