Comparing Partial and Total Tibial-Nerve Axotomy: Long-Term Effects on Prevalence and Location of Evoked Pain Behaviors

Monophasic (one-time) nerve injuries heal without clinically significant residua in most cases, but rare individuals are left with neuropathic pain, even after seem- ingly minor lesions. The effects of lesion size on risk for chronic pain persistence are not well understood, particularly as concerns the complex regional pain syndrome, which is defined in part by pain “disproportionate” to the severity of the causative lesion, and extending outside the autonomous territory of a single nerve. To better clarify the expected prevalence of pain behaviors after nerve injury, we compared the effects in rats of different-sized axotomies on the preva- lence and location of evoked pain behaviors. To highlight clinical relevance, we also describe a patient with iatrogenic tibial-nerve injury causing similar chronic neuralgia. Adult male Sprague-Dawley rats were anesthetized and had either 1/3, 2/3 or their entire left tibial nerves tightly ligated at two sites just below the sciatic trifurcation and the interposed nerve was cut. Unoperated rats provided controls. Sensory function in the tibial and sural-innervated territories of both plantar hindpaws was assessed for as long as 6 months post- operatively. Soon after surgery, evoked pain behavior devel- oped in the ipsilesional sural-innervated site in a subset of axotomized rats and recovery was variable. The relationship between lesion size and prevalence and severity of hyperal- gesia varied for different pain behaviors, with pinprick hype- ralgesia clearly more likely after larger axotomies. In summary, partial tibial-nerve injury in rats models human disease and suggests that expectations of proportionality between lesion size and development of neuropathic pain may need revision

The Long-Term Changes In Pain-Related Symptomatology Of Inguinal Hernia Following 2 Different Herniorrhaphy Techniques

Background/aim: To compare the changes in pain-related symptoms of inguinal hernias from initial admission to postoperative month 6 following 2 herniorrhaphy techniques. Materials and methods: Patients with unilateral inguinal hernias were scheduled for either Lichtenstein or self-gripping polypropylene mesh repair. Patients were preoperatively evaluated with a visual analog scale (VAS) and a Turkish version of the Douleur Neuropathique 4 (DN4) questionnaire and the complaints related to pain were noted. After surgery, patients were discharged without early complications. Patients were reassessed at postoperative month 6. The late-term complaints of pain as well as neurological findings were evaluated using the VAS and the Turkish version of the DN4 questionnaire. Quality of life was also assessed with the Nottingham Health Profile (NHP). Results: Thirty-four patients underwent conventional Lichtenstein repair and 19 patients underwent self-gripping polypropylene mesh repair. Even though decreases in VAS intensity scores for both hernia repair techniques were noted at postoperative month 6 when compared to the preoperative period, no significant changes were found in pain, VAS, total DN4, or NHP scores between groups. Conclusion: Despite its ease of application and short time duration, self-gripping polypropylene mesh repair was not found to be superior to conventional Lichtenstein hernia repair in terms of reducing pain related to inguinal hernia.WoSScopu