Effects of cryoanalgesia on post-thoracotomy pain and on the structure of intercostal nerves: a human prospective randomized trial and a histological study.

OBJECTIVE: The choice of analgesia in the management of post-thoracotomy pain remains controversial. Although several alternative forms of post-thoracotomy analgesia exist, all have their disadvantages. Cryoanalgesia, localized freezing of intercostal nerves, has been reported to have variable effectiveness and an incidence of long-term cutaneous sensory changes. We carried out an animal study to assess the reversibility of histological changes induced by cryoanalgesia and a prospective randomized trial to compare the effectiveness of cryoanalgesia with conventional analgesia (parenteral opiates). METHODS: In six anaesthetized dogs, intercostal nerves were exposed to a varying duration of cryo-application (30, 60, 90 and 120 s). The nerves were biopsied and examined histologically at regular intervals over the following 6 months. In the clinical study, 200 consecutive patients undergoing thoracotomy were randomized to cryoanalgesia and conventional (parenteral opiates) analgesia groups. Postoperative pain scores, respiratory function tests and use of opiate analgesia were measured for the two groups. RESULTS: Following application of the cryoprobe, degeneration and fragmentation of the axons was evident with associated inflammatory changes. As the endoneurium remained intact, axonal regeneration took place after the resolution of axonal swelling. Over the course of weeks, recovery of the intercostal nerve occurred and was complete after 1 month for the 30 and 60 s groups. For nerves exposed to longer durations of cryoanalgesia, the time taken for complete recovery was proportionally increased. Clinically, there was a statistically significant (P<0.05) improvement in postoperative pain scores and use of opiate analgesia and an improvement (P>0.05) in respiratory function tests for patients in the cryoanalgesia group. The previously suggested cutaneous sensory changes resolved within 6 months with complete restoration of function. CONCLUSIONS: We suggest that cryoanalgesia be considered as a simple, inexpensive, long-term form of post-thoracotomy pain relief, which does not cause any long-term histological damage to intercostal nerves.

Low incidence of clinically significant gastroduodenal pathology despite a high incidence of Helicobacter pylori infection.

Gastric Helicobacter pylori infection is common throughout the tropics yet does not always correlate with the incidence of serious upper gastrointestinal pathology. In a consecutive series of 213 patients examined by gastroscopy for dyspepsia in northern Nigeria, 176 (92%) of 193 with acceptable biopsies had gastritis. Only 16 (8%) had a histologically normal gastric mucosa. H. pylori was present in 161 of 192 patients (84%); 31/41 (75%) with chronic gastritis and 130/135 (96%) with active gastritis. Serious pathology, ulcer and gastric cancer were present in only 29 (14%).

Helicobacter pylori infection and gastritis in healthy Nigerians.

In a study of forty asymptomatic volunteers from northern Nigeria; 35 (87.5%) had histological gastritis and 32 (80%) were infected by Helicobacter pylori. All but one of the patients infected by Helicobacter Pylori had histological gastritis. This high prevalence of H. Pylori infection in young, asymptomatic subjects, occurs in an area with a low prevalence of duodenal ulcer. The possible reasons for this are discussed.

Helicobacter pylori clearance in the treatment of non-ulcer dyspepsia.

One hundred and thirty north Nigerian patients with non-ulcer dyspepsia were treated with tripotassium dicitrato bismuthate and amoxycillin, or antacid. Symptoms resolved in 28 (33%) of bismuth and amoxycillin recipients completing the trial compared with 1 (4%) of the antacid recipients. Symptomatic improvement did not relate to clearance of Helicobacter pylori.

Non-ulcer dyspepsia in Nigeria: a case-control study.

Non-ulcer dyspepsia is common in Africa, yet there are few data on its possible cause. In this study 40 patients with strictly defined non-ulcer dyspepsia were matched with 40 asymptomatic volunteers. Both groups were questioned concerning their intake of alcohol, cola nut, non-steroidal anti-inflammatory drugs, and smoking. They then underwent upper gastrointestinal endoscopy with mucosal biopsy of the gastric mucosa: these biopsies were examined for gastritis and Helicobacter pylori. Ingestion of cola nut was the only statistically significant difference between the two groups. A high prevalence of gastritis and H. pylori infection was found in both groups, suggesting that these factors are not important in the aetiology of non-ulcer dyspepsia in northern Nigeria.