Sensory Nerve Injury Research Articles

Analysis of lumbar plexopathies and nerve injury after lateral retroperitoneal transpsoas approach: diagnostic standardization

The minimally invasive lateral transpsoas approach has become an increasingly popular means of fusion. The most frequent complication is related to lumbar plexus nerve injuries; these can be diagnosed based on distribution of neurological deficit following the motor and/or sensory nerve injury. However, the literature has failed to provide a clinically relevant description of these complications. With accurate clinical diagnosis, spine practitioners can provide more precise prognostic and management recommendations to include observation, nerve blocks, neurodestructive procedures, medications, or surgical repair strategies. The purpose of this study was to standardize the clinical findings of lumbar plexopathies and nerve injuries associated with minimally invasive lateral retroperitoneal transpsoas lumbar fusion. A thorough literature search of the MEDLINE database up to June 2012 was performed to identify studies that reported lumbar plexus and nerve injuries after the minimally invasive lateral retroperitoneal transpsoas approach. Included studies were assessed for described neurological deficits postoperatively. Studies that did attempt to describe nerve-related complications clinically were excluded. A clinically relevant assessment of lumbar plexus nerve injury was derived to standardize early diagnosis and outline prognostic implications. A total of 18 studies were selected with a total of 2310 patients; 304 patients were reported to have possible plexus-related complications. The incidence of documented nerve and/or root injury and abdominal paresis ranged from 0% to 3.4% and 4.2%, respectively. Motor weakness ranged from 0.7% to 33.6%. Sensory complications ranged from 0% to 75%. A lack of consistency in the descriptions of the lumbar plexopathies and/or nerve injuries as well as a lack of diagnostic paradigms was noted across studies reviewed. Sensory dermal zones were established and a standardized approach was proposed. There is underreporting of postoperative lumbar plexus nerve injury and a lack of standardization of clinical findings of neural complications related to the minimally invasive lateral retroperitoneal transpsoas approach. The authors provide a diagnostic paradigm that allows for an efficient and accurate classification of postoperative lumbar plexopathies and nerve injuries.

Morphological differences in skeletal muscle atrophy of rats with motor nerve and/or sensory nerve injury.

Skeletal muscle atrophy occurs after denervation. The present study dissected the rat left ventral root and dorsal root at L4-6 or the sciatic nerve to establish a model of simple motor nerve injury, sensory nerve injury or mixed nerve injury. Results showed that with prolonged denervation time, rats with simple motor nerve injury, sensory nerve injury or mixed nerve injury exhibited abnormal behavior, reduced wet weight of the left gastrocnemius muscle, decreased diameter and cross-sectional area and altered ultrastructure of muscle cells, as well as decreased cross-sectional area and increased gray scale of the gastrocnemius muscle motor end plate. Moreover, at the same time point, the pathological changes were most severe in mixed nerve injury, followed by simple motor nerve injury, and the changes in simple sensory nerve injury were the mildest. These findings indicate that normal skeletal muscle morphology is maintained by intact innervation. Motor nerve injury resulted in larger damage to skeletal muscle and more severe atrophy than sensory nerve injury. Thus, reconstruction of motor nerves should be considered first in the clinical treatment of skeletal muscle atrophy caused by denervation.

Complications Following Distal Biceps Repair

Distal biceps rupture is a relatively uncommon injury. Surgical repair is performed in patients who seek increased flexion and supination strength over that which results from nonoperative treatment. The purpose of this study was to evaluate complications associated with surgical repair of the distal biceps tendon in a large series of patients. We retrospectively reviewed 198 consecutive patients with distal biceps ruptures treated with surgical repair, and evaluated time from injury to repair, surgical technique, and complications. A total of 72 patients (36%) developed complications; 6 patients underwent additional surgery. Minor complications included lateral antebrachial cutaneous nerve paresthesia (26%), radial sensory nerve paresthesia (6%), and superficial infection (2%). Major complications included posterior interosseous nerve injury (4%), symptomatic heterotropic ossification (3%), and re-rupture (2%). Minor complications were common after distal biceps tendon repair; however, most were sensory nerve injuries that resolved with time. Major complications were infrequent, and few patients required revision surgery. Complications were more common after distal biceps tendon repair performed more than 28 days after rupture. Therapeutic IV.

Rewiring of Afferent Fibers in the Somatosensory Thalamus of Mice Caused by Peripheral Sensory Nerve Transection

The remodeling of neural circuitry and changes in synaptic efficacy after peripheral sensory nerve injury are considered the basis for functional reorganization in the brain, including changes in receptive fields. However, when or how the remodeling occurs is largely unknown. Here we show the rapid rewiring of afferent fibers in the mature ventral posteromedial thalamic nucleus of mice after transection of the peripheral whisker sensory nerve, using the whole-cell voltage-clamp technique. Transection induced the recruitment of afferent fibers to a thalamic relay neuron within 5-6 d of injury. The rewiring was pathway specific, but not sensory experience dependent or peripheral nerve activity dependent. The newly recruited fibers mediated small EPSCs, and postsynaptic GluA2-containing AMPA receptors were selectively upregulated at the new synapses. This rapid and pathway-specific remodeling of thalamic circuitry may be an initial step in the massive axonal reorganization at supraspinal levels, which occurs months or years after peripheral sensory nerve injury.

Primary repair of crush nerve injuries by means of biological tubulization with muscle‐vein‐combined grafts

Despite extensive research and surgical innovation, the treatment of peripheral nerve injuries remains a complex issue, particularly in nonsharp lesions. The aim of this study was to assess the clinical outcome in a group of 16 patients who underwent, in emergency, a primary repair for crush injury of sensory and mixed nerves of the upper limb with biological tubulization, namely, the muscle-vein-combined graft. The segments involved were sensory digital nerves in eight cases and mixed nerves in another eight cases (four median nerves and four ulnar nerves). The length of nerve defect ranged from 0.5 to 4 cm (mean 1.9 cm). Fifteen of 16 patients showed some degree of functional recovery. Six patients showed diminished light touch (3.61), six had protective sensation (4.31), and three showed loss of protective sensation (4.56) using Semmes-Weinstein monofilament test. All the patients who underwent digital nerve repair had favorable results graded as S4 in one case, S3+ in six cases, and S3 in one case. With respect to mixed nerve repair, we observed two S4, two S3+, two S3, one S2, and one S0 sensory recovery. Less favorable results were observed for motor function with three M4, one M3, two M2, and two M0 recoveries. Altogether, the results of this retrospective study demonstrates that tubulization nerve repair in emergency, in case of short nerve gaps, may restore the continuity of the nerve avoiding secondary nerve grafting. This technique preserves donor nerve and, in case of failure, does not preclude a delayed repair with a nerve graft.

Differences in Damage to CGRP Immunoreactive Sensory Nerves After Two Lumbar Surgical Approaches

Immunohistochemical study. To evaluate invasive surgical approaches by analyzing the number of sensory nerve fibers at 2 back muscle sites in rats and humans and the number of injured nerve fibers innervating these 2 sites after muscle injury in rats. SUMMARY OF BACKGROUND DATA.: Several minimally invasive approaches have recently become popular in the treatment of lumbar spine disorders. Minimally invasive surgery (MIS) is not invasive to back muscle and is thought to reduce low back pain. Muscle damage has been generally evaluated by magnetic resonance imaging (MRI); however, damage to sensory nerve fibers in and around back muscle that is directly related to pain has apparently not been explored. Human muscle at L4-L5 was obtained from the paraspinous process (during a midline approach) and from paraspinal back muscle (during a Wiltse paraspinal approach) (n = 10 each). The muscle was sectioned and immunostained for calcitonin gene-related peptide (CGRP). To detect dorsal root ganglion (DRG) neurons innervating back muscle in rats, Fluoro-Gold (FG) was applied to the same 2 sites on the lower back muscle at L4-L5 (only application, n = 12; application of FG + muscle injury, n = 12). DRGs were harvested and immunostained for CGRP and activating transcription factor-3 (ATF-3: marker for nerve injury). The numbers of FG-labeled CGRP-immunoreactive or FG-labeled ATF-3-immunoreactive DRG neurons innervating the 2 sites were counted and compared. CGRP-immunoreactive sensory nerve fibers were found at the 2 sites. The average number of CGRP-immunoreactive sensory nerve fibers in muscle obtained in a midline approach was significantly higher than that in muscle obtained in a Wiltse paraspinal approach (P < 0.01). The numbers of FG-labeled CGRP- and ATF-3-immunoreactive DRG neurons innervating paraspinous process muscle were significantly greater than those innervating paraspinal back muscle in rats (P < 0.01). There are more CGRP-immunoreactive sensory nerve fibers and DRG neurons innervating muscle in the midline approach area than in the Wiltse paraspinal approach area in humans and rats. There are more ATF-3-immunoreactive DRG neurons innervating muscle in the midline approach area than in the Wiltse paraspinal approach area after muscle injury in rats. This result may show the differences in sensory nerve injury during the 2 surgical approaches.

Evaluation of the safe zone for percutaneous Kirschner‐wire placement in the distal radius: Cadaveric study

Distal radius fractures are a common injury that is often reduced with percutaneous K-wires. The sensory nerves in this area are at risk of injuring from pin placement. Cadaveric studies of the nerve distribution patterns have elucidated certain safe zones for pin placement that limits the risk of sensory nerve injury. These studies have advocated a limited open technique that involves a shallow incision followed by blunt dissection to the bone before a k-wire is drilled into the radius. A previously identified safe zone in the anatomical snuffbox was evaluated in 40 cadaver wrists for k-wire placement via a percutaneous technique that involves putting the pin directly through the skin without an incision or blunt dissection. After k-wire placement each wrist was dissected and sensory nerve distribution relative to the pin placement was evaluated. The variability of the distribution of the sensory nerves, namely the lateral antebracheal cutaneous nerve and the superficial branch of the radial nerve, is such that no truly safe zone exists for pin placement with the percutaneous technique in this area.

Morbidity of Sentinel Node Biopsy: Relationship Between Number of Excised Lymph Nodes and Patient Perceptions of Lymphedema

Sentinel lymph node biopsy (SLNB) is associated with reduced morbidity, although lymphedema remains a significant complication. Previously, we found no association between number of excised lymph nodes (LNs) and measured lymphedema in SLNB patients. In this analysis, we examined the relationship between number of LNs excised during SLNB and patient-perceived lymphedema. A total of 600 women who underwent SLNB for breast cancer were prospectively studied. Measured lymphedema was evaluated by circumferential bilateral upper-extremity measurements taken preoperatively and 3-8 years postoperatively. Patient-perceived lymphedema was evaluated by interview at follow-up. The relationship between lymphedema, total LNs excised, and clinicopathologic variables was assessed with Fisher's exact test, Wilcoxon rank-sum test, kappa statistic, and McNemar's test. At a median of 5 years, 18 (3%) patients reported perceived lymphedema. More LNs were excised in patients with perceived lymphedema compared with those without (median, 5.5 vs. 3; p = 0.01). Only 6 of 18 women with perceived lymphedema had objectively measured lymphedema (kappa = 0.22). Patients with numbness more likely reported perceived lymphedema (p = 0.03) and had more LNs excised (p = 0.02). Women with surgery on the nondominant axilla were less likely to perceive arm swelling, regardless of the presence of measured lymphedema. After SLNB alone, patient-perceived lymphedema is uncommon, but its prevalence increases with more LNs excised. There is poor agreement between patient perceptions and objective measures. Our data suggest that factors other than limb enlargement, such as sensory nerve injury resulting from retrieval of more LNs and laterality of surgery, may play a significant role in patient perception of lymphedema after SLNB.

Volumetric Facelift: Evaluation of Rhytidectomy with Alloplastic Augmentation

Facial aging occurs as a result of soft tissue atrophy and resorption of the bony skeleton, which results in a loss of soft tissue volume and laxity of the overlying skin. Volumetric augmentation is a key component of facial rejuvenation surgery, and should be considered of equal importance to soft tissue lifting. Augmentation can be accomplished with synthetic fillers, autologous grafts, soft tissue repositioning techniques, and/or alloplastic implants. Only alloplastic implants, however, provide truly long-term volumetric correction. To date, there have been no large series dealing with the complications and results of implantation performed concurrently with rhytidectomy, which we have termed "volumetric rhytidectomy." We present our experience with 100 patients treated with a combination of malar and chin implants and rhytidectomy, compared to 200 patients who underwent rhytidectomy alone. The authors performed a retrospective review of patients treated with a combination of silicone malar and chin augmentation with rhytidectomy versus patients treated with rhytidectomy alone. Both groups of patients underwent close postoperative evaluation at 3 days, 1 week, 2 weeks, and 1 month. All patients were surveyed at 6 months to assess aesthetic satisfaction. Complication rates were noted and tabulated. Statistical analysis was performed to evaluate for any differences in the two groups. Between 2002 and 2006, 100 patients underwent malar and chin implantation along with rhytidectomy; 200 patients underwent rhytidectomy alone. In the first group, there were a total of 6 cases in which implant removal was necessary, and 2 cases in which revision was required. There were no statistically significant differences (p < 0.05) observed between the two groups with respect to major or minor hematoma, seroma, infection, sensory nerve injury, facial nerve injury, hypertrophic scarring, dehiscence, skin sloughing, or revision. Volumetric rhytidectomy reliably augments the malar and mental areas, allows for subtle skeletal contouring, and results in successful rejuvenation. Rhytidectomy is relatively safe to perform concurrently with silicone augmentation, and does not result in an increased complication rate as compared to rhytidectomy alone.

Evaluating Patients With Chronic Pain After Breast Cancer Surgery

CHRONIC PAIN AFTER BREAST CANCER SURGERY OCcurs in approximately 50% of patients. The severity is variable, but sensory disturbances including paresthesias and phantom breast phenomena occur in approximately 47%. Potentially, this problem may increase with higher incidence of detected breast cancer and improved survival. Reasons for chronic discomfort after surgery are varied and complex, but nerve damage associated with axillary lymph node dissection is the most commonly reported cause and is associated with a doubling in prevalence compared with cases without this procedure. Interactions among treatment modalities such as type of breast surgery, axillary procedures, adjuvant chemotherapy, and radiation therapy add to the difficulty involved in the overall evaluation. In this issue of JAMA, Gartner and colleagues report findings from a cross-sectional study from Denmark that evaluated women undergoing an operation for unilateral primary breast cancer and documented the prevalence, location, severity, and frequency of persistent pain and sensory disturbances in 12 well-defined treatment groups. More than 3000 women completed questionnaires that addressed issues of specific regions of symptoms, severity of pain, frequency of symptoms, physician visits due to pain in the operated region, use of analgesics or other treatment for pain in the operated region, and pain in other locations. The responses were also analyzed with regard to age of the patient and treatment modalities for the breast cancer. The results are compelling. Almost half (47%) of the respondents reported pain in one or more areas, and 52% of those patients rated the discomfort as severe or moderate. As many as 76% of patients with severe pain experienced discomfort on a daily basis. The breast area was the most frequently reported site of pain, followed by the axilla, the arm, and the side of the body, and 40% experienced pain in other nonsurgical areas. The use of analgesics was relatively prevalent; other modalities for relief of pain such as physiotherapy and massage were also used. Predictive factors most significantly associated with chronic pain included young age (18-39 years), especially if the patient was treated with breast-conserving surgery. Treatment with adjuvant radiation therapy, but not chemotherapy, increased the risk for development of pain. Mastectomy carried a higher risk for moderate and severe distress compared with breast-conserving surgery. Axillary node dissection was more often associated with frequency of pain as well as severity of pain than sentinel node biopsy, regardless of the type of surgery to the breast. Patients with complaints of pain in other areas of the body were more likely to develop increased pain in the surgical site (65%) compared with women without pain in nonsurgical sites (37%). Sensory disturbance was more frequently reported by younger patients. The likelihood for development of any sensory discomfort was highest for patients treated with breastconserving surgery, axillary lymph node dissection, and chemotherapy with breast radiation therapy or breast and localregional radiation therapy. Of patients who reported sensory disturbances, 65% also experienced a type of pain suggesting that sensory abnormalities and nerve injury may lead to increased pain risk. Comparisons with other studies examining this issue may be difficult due to inconsistencies in definitions of chronic pain, different measurements of pain, studies from single institutions, changes in mix of surgical techniques and adjuvant treatment over time, and variable intervals in assessment of pain after surgery. Insufficient numbers of patients may also limit conclusions. An advantage of the study by Gartner et al is the large number of patients, 3253 nationwide, compared with other studies with 85 to 1600 patients. The larger population provides better risk estimates for all treatment modalities. Also, treatment principles are standardized at all breast cancer treatment facilities in Denmark according to European guidelines and national

Preconditioning selective ventral root injury promotes plasticity of ascending sensory neurons in the injured spinal cord of adult rats – possible roles of brain‐derived neurotrophic factor, TrkB and p75 neurotrophin receptor

Preconditioning sciatic nerve injury enhances axonal regeneration of ascending sensory neurons after spinal cord injury. A key question is whether direct injury of sensory nerves is necessary for the enhanced regeneration. The lumbar 5 ventral root transection (L5 VRT) model, a model of selective motor nerve injury, provides a useful tool to address this question. Here we examined the effects of a preconditioning L5 VRT on the regeneration after a subsequent dorsal column transection (DCT) in adult Sprague-Dawley rats. We found that L5 VRT 1 week before DCT increased the number of Fast Blue (FB)-labeled neurons in the L5 dorsal root ganglia (DRG) and promoted sprouting/regenerating axons to grow into the glial scar. L5 VRT also induced a dramatic upregulation of expression of brain-derived neurotrophic factor (BDNF) in the preconditioned DRG and in the injured spinal cord. Moreover, almost all of the FB-labeled sprouting/regenerating neurons expressed BDNF, and approximately 55% of these neurons were surrounded by p75 neurotrophin receptor-positive glial cells. This combined injury led to an increase in the number of BDNF- and TrkB-immunoreactive nerve fibers in the dorsal column caudal to the lesion site. Taken together, these findings demonstrate that L5 VRT promotes sprouting/regeneration of ascending sensory neurons, indicating that sensory axotomy may not be essential for the plasticity of injured dorsal column axons. Thus, the sensory neurons could be preprimed in the regenerative milieu of Wallerian degeneration and neuroinflammation, which might alter the expression of neurotrophic factors and their receptors, facilitating sprouting/regeneration of ascending sensory neurons.

Analgesia preventiva con pregabalina en intervenciones de hernia con malla. Revisión al año

Objective Preventive analgesia consists of administrating drugs to achieve an analgesic state that decreases the peripheral and central sensory response to pain prior to surgical injury; thus, the aim is to break the cycle of inflammation-pain-hyperalgesia-increase of painful stimulus. Pregabalin is a neuro-regulator used in the treatment of neuropathic pain and several studies indicate that this drug can be administered to prevent postoperative pain symptoms. The aim of this study was to compare postoperative pain in patients undergoing open mesh hernia repair, treated either with or without pregabalin. Material and methods A prospective randomized trial was conducted in 140 patients (112 men and 28 women) who underwent open inguinal, crural or umbilical hernia repair with mesh. Group I consisted of 70 patients treated with pregabalin 75 mg at night for 3 days before the intervention and 75 mg at night for 12 days after the procedure, including the day of surgery. Group II consisted of 70 patients not administered pregabalin. There were no differences between the two groups in age, which ranged between 18 and 79 years old (mean age 55.47 ± 13.38), or in ASA grade (between I and III). Pain assessment was based on the visual analog scale (VAS) and pyrazolone consumption. The results were analyzed 1, 6, and 12 months after the intervention. Adverse effects, hours or sleep and quality of sleep were registered. The statistical analysis was performed using the Kolmogorov-Smirnov test with the Statgraphics program. P values of < 0.05 were considered statistically significant. Results Analgesic results were as follows: group I: 1 month: good in 86%, medium in 14% and poor in 0%; 6 months: good in 89%, medium in 11% and poor in 0%; 12 months: good in 94%, medium in 6% and poor in 0%. Neuropathic pain occurred in 35% (75% pure and 25% mixed). Group II: 1 month: good in 56%, medium in 34% and poor in 10%; 6 months: good in 70%, medium in 22% and poor in 8%; 12 months: good in 83%, medium in 13% and poor in 4%. Neuropathic pain occurred in 85% (70% pure and 30% mixed). In both groups, pure nociceptive pain disappeared in the first 3-4 weeks. There was a statistically significant difference (p < 0.05) between the two distributions with a 95% confidence level; accordingly, the analgesic results showed statistically significant differences in distinct determinations in each group. In group I, hours of sleep increased in 56% of the patients and quality of sleep improved in 60%; these changes were not observed in group II. Adverse effects (10%) appeared only in group I (dizziness in five, drowsiness in one and migraine in one). Conclusions Iatrogenic chronic neuropathic pain due to sensory nerve injury in open hernia repair is the most frequent cause of persistent postoperative pain. Preventive analgesia with pregabalin reduces the incidence of this pain. However, further studies are required to confirm this result.

Sensory nerve injury following impacted mandibular third molar extraction: the Lagos University Teaching Hospital experience.

Objective: To investigate the prevalence and pattern of sensory nerve injuries after surgical removal of impacted mandibular third molars. Methods: A study of patients who required surgical extraction of impacted mandibular third molars between October 2003 and May 2006 at the Lagos University Teaching Hospital (LUTH) was carried out. Data collected from each patient included age, sex and the indication for extraction. Also collected were the angulation of the tooth and surgical difficulty as measured by the total time of surgery. All extractions were performed under local anaesthesia and the buccal guttering technique was used for all extractions. Postoperatively, any occurrences of sensory nerve injuries and the time it took for the patients to recover from it were recorded. Result: A total of 340 impacted third molars were removed from 335 patients. There were 156 (46.5%) males and 179 (53.4%) females with a male female ratio of 1:1.2. The age ranged from 17 to 55 years with a mean of 26.63 ± 7.39 years. Fifty extractions (14.7%) of the 340 extractions had postoperative complications, of these 2.6% (9 patients) had sensory nerve defects postoperatively. There were five females (0.3% of total female populations) and four males (0.3% of male population). All cases of sensory nerve defects involved the inferior dental nerve. The incidence of inferior alveolar nerve paraesthesia was highest in the under 25 age group, the relationship to the age of patients was however not statistically significant (p = 0.87). Five (55.5%) of the cases with inferior alveolar nerve damage occurred with teeth in horizontal impactions (p = 0.018). The total time of surgery was also statistically significantly associated with the occurrence of sensory nerve injury (p = 0.001). Conclusion: Sensory nerve injury was significantly associated with both surgical difficulty and horizontal pattern of impactions. Keywords: Sensory nerve damage, impacted mandibular third molars, inferior alveolar nerveNigerian Dental Journal Vol. 16 (1) 2008: pp. 10-13

The Utah Early Neuropathy Scale: a sensitive clinical scale for early sensory predominant neuropathy.

Early neuropathy is often sensory predominant and prominently involves small-diameter nerve fibers. Established neuropathy examination scales such as the Michigan Diabetic Neuropathy Scale (MDNS) and the Neuropathy Impairment Score-Lower Leg (NIS-LL) focus primarily on large-fiber sensory and motor function. Here, we validate the Utah Early Neuropathy Scale (UENS), a physical examination scale specific to early sensory predominant polyneuropathy. Compared with other scales, the UENS emphasizes severity and spatial distribution of pin (sharp) sensation loss in the foot and leg and focuses less on motor weakness. UENS, MDNS, and NIS-LL were compared in 215 diabetic or prediabetic subjects, with (129) or without neuropathy (86), and repeated in 114 neuropathy subjects after 1 year of follow-up. Neuropathy severity was also evaluated with nerve conduction studies, quantitative sensory testing, quantitative sudomotor axonal reflex testing, and intraepidermal nerve fiber density determination. The UENS had a high degree of interrater reliability (interclass correlation of 94%). UENS correlated significantly to MDNS and NIS-LL (p < 0.01), and more significantly than MDNS or NIS-LL to confirmatory tests. In this cohort, UENS had a superior profile to receiver operating characteristic analysis across a range of scores, with a sensitivity (92%) higher than MDNS (67%) or NIS-LL (81%), without sacrificing specificity. UENS more closely correlated with change in ancillary and small-fiber neuropathy measures over 1 year follow-up than did MDNS or NIS-LL. UENS is a sensitive and reproducible clinical measure of sensory and small-fiber nerve injury and may be useful in trials of early neuropathy.

GABAA receptor modulation in dorsal root ganglia in vivo affects chronic pain after nerve injury

Neuropathic pain (NPP) due to sensory nerve injury is, in part, the result of peripheral sensitization leading to a long-lasting increase in synaptic plasticity in the spinal dorsal horn. Thus, activation of GABA-mediated inhibitory inputs from sensory neurons could be beneficial in the alleviation of NPP symptoms. Dorsal root ganglia (DRG) conduct painful stimulation from the periphery to the spinal cord. Long-lasting down-regulation in GABA tone or sensitivity in DRG neurons has been reported in animals with neuropathy. To determine the function of GABA in DRG in the development of NPP, we examined how the acute pharmacological GABAA-receptor modulation of L5 DRG in vivo affects the development of NPP in rats with crush injury to the sciatic nerve. Direct application of muscimol and gaboxadol, GABAA agonists, to L5 DRG immediately after injury induced dose-dependent alleviation, whereas bicuculline and picrotoxin, GABAA antagonists, worsened NPP postaxonal injury. The pain-alleviating effects of muscimol and gaboxadol were blocked by bicuculline. Muscimol, applied at the time of injury, caused complete and long-lasting abolishment of NPP development. However, when muscimol was applied after NPP had already developed, its pain-alleviating effect, although significant, was short-lived. Using a fluorescent tracer, sodium fluorescein, we confirmed that local DRG application results in minimal spread into the corresponding dorsal horn of the ipsilateral spinal cord. GABAA receptors in DRG are important in the development of NPP after peripheral nerve injury, making timely exogenous GABAergic manipulation at the DRG level a potentially useful therapeutic modality.

Differential Changes in TRPV1 Expression After Trigeminal Sensory Nerve Injury

We have recently demonstrated that inferior alveolar nerve and mental nerve (branches of the mandibular nerve) injury from rats serves as a valid trigeminal neuropathic pain model. In these animals, we found that neuronal loss of trigeminal ganglion (TG) was not correlated with pain hypersensitivity. In this study, we examined changes of transient receptor potential vanilloid 1 (TRPV1) expression in the injured and uninjured TG neurons using immunohistochemical analysis at 3 days after surgery, the time point where we observed significant pain hypersensitivity. Injured neurons were identified by positive immunoreactivity for activating transcription factor 3 (ATF3). ATF3 immunoreactivity was exclusively observed in the nuclei of subpopulation of ipsilateral mandibular TG neurons, whereas no ATF3 expression was found in the naive and contralateral TG neurons. Interestingly, the expression of TRPV1 was increased in the uninjured ipsilateral maxillary TG neurons as well as in the uninjured ipsilateral mandibular TG neurons. The upregulation of TRPV1 and ATF3 expression returned to the basal level at 60 days after surgery. Our results demonstrate that trigeminal sensory nerve injury induced differential changes in TRPV1 expression of the injured and uninjured TG neurons. The upregulation of TRPV1 in uninjured TG neurons may play an important role in pain hypersensitivity after trigeminal nerve injury. The TRPV1 is a well-known pain transducer molecule and plays crucial roles in the perception of inflammatory and thermal pain. This article presents that TRPV1 expression was increased in uninjured neurons rather than injured neurons after peripheral nerve injury. The upregulation of TRPV1 in uninjured neurons may be associated with the development of neuropathic pain. TRPV1 might be a potential target for the treatment of neuropathic pain.

Sensory nerve injury after uterosacral ligament suspension

Sensory nerve injury after uterosacral ligament suspension

Could Skin Retraction Incision Minimize Nerve Injury Over the Iliac Crest?

The aim of this study is to elucidate the nerve passage over the iliac crest shifted by skin retraction in harvesting iliac bone graft. A total of 44 iliac crests obtained of 22 nonembalmed Korean fresh cadavers were dissected (six males and 16 females; age range, 57-91 years). In A group (22) of "reposed skin," a skin incision was made from the anterior superior iliac spine (ASIS) to the highest level of iliac crest (HLIC). In B group (22) of "medial retraction," skin was tugged medially 1.5 cm and an incision was made from ASIS to HLIC. In A group, the nerve branches were injured in 19 (86.4%) and 15 (68.2%) in B group. Most injured nerves crossed over the iliac crest and at the posterior half site of ASIS to HLIC. The involved nerves were the subcostal nerve, iliohypogastric nerve, and ilioinguinal nerve. Subcostal nerve was less inflicted with injury in B group (one branch, 4.5%) than A group (four branches, 18.2%). P value is 0.151. Iliohypogastric nerve was significantly least injured in B group (three branches, 13.6%) compared with A group (10 branches, 45.5%). P value is 0.022. An injuring rate of ilioinguinal nerve was almost the same between A group (13 branches, 59.1%) and B group (14 branches, 63.61%). P value is 0.760. In the procedure of harvesting iliac bone graft, it is suggested to make an incision on the skin retracted medially and on the anterior half site of ASIS to HLIC to avert an injury of superficial sensory nerves.

Complications After Superficial Plane Cervicofacial Rhytidectomy: A Retrospective Analysis of 178 Consecutive Facelifts and Review of the Literature

It is well-recognized that postoperative hematoma is the most common complication of cervicofacial rhytidectomy (facelift surgery), and several strategies aimed at reducing the incidence of hematoma have been developed and studied. Other common complications include skin necrosis, seroma, motor and sensory nerve injury, alopecia, auricular deformity/displacement, and dyspigmentation. The purpose of this study was to retrospectively analyze the incidence of complications after superficial cervicofacial rhytidectomy performed by a single surgeon and his fellows and to compare our findings with those reported in the literature. Based on a retrospective chart review of patients who underwent cervicofacial rhytidectomy, 178 consecutive patients were enrolled in this study. The charts were reviewed for any notable complications after facelift surgery, especially postoperative hematoma. The charts of those patients with complications were reviewed to identify the presence of perioperative anomalies that may have increased the risk of such complications. Our findings were then compared with those reported in the literature. Of 178 patients who underwent cervicofacial rhytidectomy, 11 (6.2%) had a postoperative complications. These 11 complications included 5 cases (2.8%) of a major postoperative hematoma requiring surgical intervention, 3 cases (1.7%) of minor hematomas ("microhematomas"), and 1 case each of hypertrophic scarring necessitating surgical excision and steroid injection, superficial skin necrosis, and dehiscence. There were no cases of seroma, parotid pseudocyst, or permanent motor nerve injury. The incidence of postoperative complications associated with superficial plane rhytidectomy is very low, with hematoma the most common complication.

352 Differential changes in TRPV1 expression in trigeminal ganglion neurons following trigeminal sensory nerve injury

352 Differential changes in TRPV1 expression in trigeminal ganglion neurons following trigeminal sensory nerve injury