The Structure of the Brachial Plexus of the Djungarian Hamster (Phodopus sungorus)

Hamsters are often chosen as companion animals but are also a group of animals frequently subjected to laboratory tests. As there are no scientific publications providing information on the anatomical architecture of the brachial plexus of the Djungarian hamster, this study analyses the structure of this part of the nervous system of this species. It is important to know the details of this structure not only for cognitive reasons, but also due to the increasing clinical significance of rodents, which are often used in scientific research. The study was conducted on 55 specimens. Like in humans, the brachial plexus of the Djungarian hamster has three trunks. The following individual nerves innervating the thoracic limb of the Djungarian hamster: the radial nerve, median nerve, ulnar nerve, musculocutaneous nerve, axillary nerve, suprascapular nerve, thoracodorsal nerve, cranial pectoral nerves, caudal pectoral nerve, lateral thoracic nerve, long thoracic nerve, and subscapular nerves. Similarly to other mammals of this order, the brachial plexus of the Djungarian hamster ranges widely (C5-T1). However, its nerves are formed from different ventral branches of the spinal nerves than in other mammals.

Two clinical tests assessing long thoracic nerve function to determine C5 and C6 root graft eligibility in patients with brachial plexus injury

OBJECTIVE Identifying roots available for grafting is of paramount importance prior to reconstructing complex injuries involving the brachial plexus. This is traditionally achieved by combining input from both clinical examinations and imaging studies. In this paper, the authors describe and evaluate two new clinical tests to study long thoracic nerve function and, consequently, to predict the status of the C5 and C6 roots after global brachial plexus injuries. METHODS From March 2020 to December 2020, in 41 patients undergoing brachial plexus repair, preoperative clinical assessments were performed using modified C5 and C6 protraction tests, C5 and C6 Tinel’s signs, and MRI findings to predict whether graft-eligible C5 and C6 roots would be identified intraoperatively. Findings from these three assessments were then combined in a logistic regression model to predict graft eligibility, with overall predictive accuracies calculated as areas under receiver operating characteristic curves. RESULTS In the 41 patients, the pretest probability of C5 root availability for grafting was 85% but increased to 92% with a positive C5 protraction test and to 100% when that finding was combined with a positive C5 Tinel’s sign and favorable MRI findings. The pretest probability of C6 root availability was 40%, which increased to 84% after a positive C6 protraction test and to 93% when the protraction test result concurred with Tinel’s test and MRI findings. CONCLUSIONS Combining observations of the protraction tests with Tinel’s sign and MRI findings accurately predicts C5 and C6 root graft eligibility.

Risk Analysis of Needle Injury to the Long Thoracic Nerve during Ultrasound-Guided C7 Selective Nerve Root Block

Background and Objectives: Ultrasound (US)-guided cervical selective nerve root block (SNRB) is a widely used treatment for upper limb radicular pain. The long thoracic nerve (LTN) passes through the middle scalene muscle (MSM) at the C7 level. The needle trajectory of US-guided C7 SNRB pierces the MSM, therefore indicating a high probability of injury to the LTN. We aimed to identify the LTN and to investigate the risk of needle injury to the nerve during US-guided C7 SNRB. Materials and Methods: This retrospective observational study included 30 patients who underwent US-guided SNRB at the C7 level in a university hospital. We measured the maximal cross-sectional diameter (MCSD) of the LTN and cross-sectional area (CSA) of the C7 nerve root and assessed the injury risk of LTN during US-guided C7 SNRB by simulating the trajectory of the needle in the ultrasound image. Results: The LTN was detectable in all the cases, located inside and outside the MSM in 19 (63.3%) and 11 (36.7%) of cases, respectively. The LTN’s mean MCSD was 2.10 mm (SD 0.13), and the C7 root’s CSA was 10.78 mm2 (SD 1.05). The LTN location was within the simulated risk zone in 86.7% (26/30) of cases. Conclusion: Our findings suggest a high potential for LTN injury during US-guided C7 SNRB. The clear visualization of LTNs in the US images implies that US guidance may help avoid nerve damage and make the procedure safer. When performing US-guided C7 SNRB, physicians should take into consideration the location of the LTN.

Iatrogenic injury to long thoracic nerve following thoracotomy for right thoracic scoliosis in Marfan syndrome: a case report

Background Patients with Marfan syndrome commonly require spinal deformity surgery. The purpose of this case report is to present a rare thoracotomy complication. We present the management of such a patient. Case summary In a known case of Marfan syndrome, an 18-year-old Persian man was admitted to our hospital with scoliosis. The patient underwent radiological examinations, and thoracic scoliosis of 70° was diagnosed. A right thoracotomy for anterior spinal fusion from the sixth rib and posterior spinal fusion were performed successfully. Two months later, he was readmitted because of winging of the right scapula due to serratus anterior palsy. Electromyography and nerve conduction velocity confirmed long thoracic nerve injury. Conservative treatment was provided. Ultimately, the patient recovered completely in the last follow-up visit 6 months after the surgery. Discussion This is the first report of ipsilateral winged scapula after thoracotomy. Attention needs to be paid to surgical techniques in patients with Marfan syndrome.