Ultrasonographic identification of lateral femoral cutaneous nerve anatomical variation in persistent meralgia paresthetica:A case report

BACKGROUND Meralgia paresthetica(MP)is an entrapment mononeuropathy of the lateral femoral cutaneous nerve(LFCN).Although structural abnormalities in nerve tissues can be confirmed using ultrasonography,this is not routinely performed.CASE SUMMARY Herein,we present the case of a 52-year-old woman who developed MP after laparoscopic gynecological surgery.The patient was referred to our clinic from an obstetrics and gynecology clinic with symptoms of numbness and a tingling sensation in the left anterolateral thigh,which developed after surgery performed 5 mo earlier.Tests were performed to assess the disease status and determine the underlying causes.Ultrasonographic examination revealed an anatomical variation,where the left LFCN was entrapped within the inguinal ligament.This case suggests that performing ultrasonographic examination before and after surgery in the lithotomy position could help prevent MP.CONCLUSION This case demonstrates the value of ultrasonography in detecting anatomical variation and diagnosing persistent MP.Ultrasonography should be considered an adjunct to electromyography for optimal MP management.Further,this case would help other clinicians determine patient prognosis and decide on targeted treatment strategies.

Natural history of sensory nerve recovery after cutaneous nerve injury following foot and ankle surgery

Cutaneous nerve injury is the most common complication following foot and ankle surgery. However, clinical studies including long-term follow-up data after cutaneous nerve injury of the foot and ankle are lacking. In the current retrospective study, we analyzed the clinical data of 279 patients who underwent foot and ankle surgery. Subjects who suffered from apparent paresthesia in the cutaneous sensory nerve area after surgery were included in the study. Pa- tients received oral vitamin B^2 and methylcobalamin. We examined final follow-up data of 17 patients, including seven with sural nerve injury, five with superficial peroneal nerve injury, and five with plantar medial cutaneous nerve injury. We assessed nerve sensory function using the Medical Research Council Scale. Follow-up immediately, at 6 weeks, 3, 6 and 9 months, and 1 year after surgery demonstrated that sensory function was gradually restored in most patients within 6 months. However, recovery was slow at 9 months. There was no significant difference in sensory function between 9 months and 1 year after surgery. Painful neuromas occurred in four patients at 9 months to 1 year. The results demonstrated that the recovery of sensory func- tion in patients with various cutaneous nerve injuries after foot and ankle surgery required at least 6 months.

Ultrasound-guided rectus sheath block for anterior cutaneous nerve entrapment syndrome after laparoscopic surgery:A case report

BACKGROUND Anterior cutaneous nerve entrapment syndrome is defined as abdominal pain due to entrapped intercostal nerves.This is the first report of a patient successfully treated for anterior cutaneous nerve entrapment syndrome after laparoscopic surgery with an ultrasound-guided rectus sheath block.The rectus sheath block physically lysed adhesions and relieved pain from anterior cutaneous nerve entrapment syndrome.CASE SUMMARY The patient is a 44-year-old man who presented with severe left upper abdominal pain at an operative scar one month after laparoscopic ulcer repair.Diagnosis and treatment were performed using an ultrasound-guided rectus sheath block with 0.1%lidocaine 20 mL.The pain was relieved after the block.The diagnosis was anterior cutaneous nerve entrapment syndrome.Rectus sheath block may be effective for patients with anterior cutaneous nerve entrapment syndrome.CONCLUSION Ultrasound-guided rectus sheath block is a promising treatment modality for patients with postoperative anterior cutaneous nerve entrapment syndrome due to adhesions.

Injury of Muscular but not Cutaneous Nerve Drives Acute Neuropathic Pain in Rats

Acute pain is a common complication after injury of a peripheral nerve but the underlying mechanism is obscure.We established a model of acute neuropathic pain via pulling a pre-implanted suture loop to transect a peripheral nerve in awake rats.The tibial(both muscular and cutaneous),gastrocnemius-soleus(muscular only),and sural nerves(cutaneous only)were each transected.Transection of the tibial and gastrocnemius-soleus nerves,but not the sural nerve immediately evoked spontaneous pain and mechanical allodynia in the skin territories innervated by the adjacent intact nerves.Evans blue extravasation and cutaneous temperature of the intact skin territory were also significantly increased.In vivo electrophysiological recordings revealed that injury of a muscular nerve induced mechanical hypersensitivity and spontaneous activity in the nociceptive C-neurons in adjacent intact nerves.Our results indicate that injury of a muscular nerve,but not a cutaneous nerve,drives acute neuropathic pain.

End-to-side neurorrhaphy repairs peripheral nerve injury：sensory nerve induces motor nerve regeneration

End-to-side neurorrhaphy is an option in the treatment of the long segment defects of a nerve.It involves suturing the distal stump of the disconnected nerve（recipient nerve） to the side of the intimate adjacent nerve（donor nerve）.However,the motor-sensory specificity after end-to-side neurorrhaphy remains unclear.This study sought to evaluate whether cutaneous sensory nerve regeneration induces motor nerves after end-to-side neurorrhaphy.Thirty rats were randomized into three groups：（1） end-to-side neurorrhaphy using the ulnar nerve（mixed sensory and motor） as the donor nerve and the cutaneous antebrachii medialis nerve as the recipient nerve;（2） the sham group：ulnar nerve and cutaneous antebrachii medialis nerve were just exposed;and（3） the transected nerve group：cutaneous antebrachii medialis nerve was transected and the stumps were turned over and tied.At 5 months,acetylcholinesterase staining results showed that 34% ± 16% of the myelinated axons were stained in the end-to-side group,and none of the myelinated axons were stained in either the sham or transected nerve groups.Retrograde fluorescent tracing of spinal motor neurons and dorsal root ganglion showed the proportion of motor neurons from the cutaneous antebrachii medialis nerve of the end-to-side group was 21% ± 5%.In contrast,no motor neurons from the cutaneous antebrachii medialis nerve of the sham group and transected nerve group were found in the spinal cord segment.These results confirmed that motor neuron regeneration occurred after cutaneous nerve end-to-side neurorrhaphy.