Somatosensory Evoked Potentials Testing Research Articles

The Effect of Antinociceptive Dose of Morphine on Cell Therapy in Rats with Spinal Cord Injury.

Spinal cord injury (SCI) is a sensory-motor injury. Today, combined treatments such as cell therapy along with drug therapy and their interactions are of interest. Morphine is an opioid drug used to relieve intolerable pain. This study aims to evaluate the impact of an antinociceptive dose of morphine (with minimal tolerance/dependence but effective pain relief) on cell therapy in SCI. The antinociceptive dose of morphine was determined in rats with SCI through the Hargreaves and naloxone-induced morphine withdrawal tests. The rats were then allocated to 5 groups: laminectomy, SCI, SCI + Morphine, SCI + cell therapy, SCI + Morphine + cell therapy. The antinociceptive dose (5 mg/kg) was administered on days 1, 4, 10, and 13 (i.p.) post-SCI. On day 7, Neural-like stem cells derived from adipose tissue were transplanted intraspinally into the injured animals, and they were monitored for 12 weeks. The outcomes were assessed using the BBB test, somatosensory evoked potential (SSEP), and histology. The BBB test indicated that morphine significantly hindered functional recovery post-cell transplantation compared to animals receiving only cell therapy (p < 0.05). In the SSEP test, the analysis of amplitude and latency of waves did not reveal a significant difference (p > 0.05). The histological results showed that cell therapy reduced the cavity size post-SCI, while morphine had no significant impact on it. Morphine at the antinociceptive dose significantly impairs motor recovery despite cell therapy. Nonetheless, there was no significant difference between groups in terms of sensory pathway outcomes.

Outcome and prognostication after cardiac arrest.

The outcome after out-of-hospital cardiac arrest has historically been grim at best. The current overall survival rate of patients admitted to a hospital is approximately 10%, making cardiac arrest one of the leading causes of death in the United States. The situation is improving with the incorporation of therapeutic temperature modulation, aggressive prevention of secondary brain injury, and improved access to advanced cardiovascular support, all of which have decreased mortality and allowed for better outcomes. Mortality after cardiac arrest is often the direct result of active withdrawal of life-sustaining therapy based on the perception that neurological recovery is not possible. This reality highlights the importance of providing accurate estimates of neurological prognosis to decision makers when discussing goals of care. The current standard of care for assessing neurological status in patients with hypoxic-ischemic encephalopathy emphasizes a multimodal approach that includes five elements: (1) neurological examination off sedation, (2) continuous electroencephalography, (3) serum neuron-specific enolase levels, (4) magnetic resonance brain imaging, and (5) somatosensory-evoked potential testing. Sophisticated decision support systems that can integrate these clinical, imaging, and biomarker and neurophysiologic data and translate it into meaningful projections of neurological outcome are urgently needed.

A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study

ObjectiveWe aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system. MethodsIn order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference. ResultsWe found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings. ConclusionIn this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application. SignificanceEstablished and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.

The capacity of neurological pupil index to predict absence of somatosensory evoked potentials after cardiac arrest—A study protocol

Anoxic-ischemic brain injury is the most common cause of death after cardiac arrest (CA). Robust methods to detect severe injury with a low false positive rate (FPR) for poor neurological outcome include the pupillary light reflex (PLR) and somatosensory evoked potentials (SSEP). The PLR can be assessed manually or with automated pupillometry which provides the neurological pupil index (NPi). We aim to describe the interrelation between NPi values and the absence of SSEP cortical response and to evaluate the capacity of NPi to predict the absence of cortical SSEP response in comatose patients after CA. A total of 50 patients will be included in an explorative, prospective, observational study of adult (>18years) comatose survivors of CA admitted to intensive care in a university hospital. NPi assessed with a hand-held pupillometer will be compared to SSEP signals recorded >48hours after CA. Primary outcomes are sensitivity, specificity, and odds ratio for NPi to predict bilateral absence of the SSEP N20 signal, with NPi values corresponding to <5% FPRs of SSEP absence. Secondary outcomes are the PLR and SSEP sensitivity, specificity, and odds ratio for poor neurological outcome at hospital discharge and death at 30days. The PLR and SSEP may have a systematic interrelation, and a certain NPi threshold could potentially predict the absence of cortical SSEP response. If this can be concluded from the present study, SSEP testing could be excluded in certain patients to save resources in the multimodal prognostication after CA. Editorial comment The interrelation between loss of the pupillary light reflex (PLR) and the loss of cortical response to a somatosensory evoked potential (SSEP) in comatose cardiac arrest patients is not known. This exploratory prospective study is designed to evaluate whether a specific degree of attenuated PLR, as measured by semiautomated pupillometry, can predict the bilateral loss of cortical SSEP response in severe anoxic/ischemic brain injury. Such an interrelation between the two methods would enable the use of pupillometry rather than the more resource demanding SSEP for neurologic prognostication in post cardiac arrest patients. ClinicalTrials.gov, NCT04720482, Registered 21 January 2021, retrospectively registered.

A Study of Differences in Penile Dorsal Nerve Somatosensory Evoked Potential Testing Among Healthy Controls and Patients With Primary and Secondary Premature Ejaculation

BackgroundPenile dorsal nerve somatosensory evoked potential (DNSEP) is a scientific and objective technique that provides effective and objective data to establish the diagnosis of premature ejaculation (PE). AimTo explore differences in DNSEP between patients with primary premature ejaculation (PPE) and those with secondary premature ejaculation (SPE), in order to investigate the clinical value of DNSEP in the diagnosis of PE. MethodsThe participants were divided into a PPE group (34 cases), an SPE group (25 cases) and a healthy control group (18 cases). All participants underwent DNSEP testing, and the latencies and amplitudes of DNSEP were recorded. OutcomesDifferences in the latencies and amplitudes of DNSEP were compared among the PPE, SPE, and healthy control groups. ResultsThe latencies of DNSEP in the PPE and SPE groups were shorter than those in the healthy control group, and these differences were statistically significant (P < 0.01). However, there was no statistically significant difference between the PPE and SPE groups (P > 0.05). The amplitudes of DNSEP in the PPE group were significantly higher than those in the healthy control group (P < 0.01). However, the amplitudes of DNSEP in the SPE group were significantly lower than those in the healthy control group (P < 0.05). Clinical ImplicationsPPE and SPE can be differentiated based on differences in the amplitudes of DNSEP, providing an objective basis for treatments and follow-up examinations. Strengths and LimitationsWe evaluated differences in the amplitudes of DNSEP between PPE and SPE patients, which were rare in the published literature. However, specific causes of these differences are still unclear. SEP only reflects afferent pathways in the ejaculatory reflex arc, and role of the brain as a higher center should not be ignored. ConclusionBoth PPE and SPE patients are characterized by an increased excitability of the penile sensory nerves. Sun Z, Liao Z, Zheng Q, et al. A Study of Differences in Penile Dorsal Nerve Somatosensory Evoked Potential Testing Among Healthy Controls and Patients With Primary and Secondary Premature Ejaculation. J Sex Med Rev 2021;18:732–736.

Abstracts from The 37th Annual National Neurotrauma Symposium June 29–July 3, 2019 Pittsburgh, Pennsylvania

Abstracts from The 37^th Annual National Neurotrauma Symposium June 29–July 3, 2019 Pittsburgh, Pennsylvania

Evoked potentials improve multimodal prognostication after cardiac arrest

AimPredicting recovery in comatose post-cardiac arrest patients requires multiple modalities of prognostic assessment. In isolation, absent N20 cortical responses in somatosensory evoked potentials (SSEPs) are a specific predictor of poor outcome. It is unknown whether SSEP results, when assessed in the context of prior knowledge (demographic and clinical information), change the pretest predicted probability of recovery. MethodsIn a single center retrospective study, a cohort of 323 patients admitted to post-cardiac arrest service at a tertiary care center were classified into a group based on SSEP testing. We built adjusted logistic regression models including clinical examination findings on the day SSEPs were recorded to generate a pre-test outcome probability for awakening, withdrawal of life-sustaining therapy (WLST) and survival to discharge. We then added the upper extremity N20 cortical response results to the model to obtain updated outcome probabilities. ROC curve was used to determine the additive effect of using SSEPs to the model. Survival to discharge, awakening, and WLST due to neurological reasons were designated as primary, secondary and tertiary outcomes, respectively. ResultsAnalyses showed that evoked potentials are ordered in sicker patients. Adding SSEP to the model increased the proportion of patients with less than 1% and 5% chance of survival, as well as the proportion of patients with over 95% chance of WLST. AUC for survival increased from 0.85 to 0.93 when SSEP was included (p = 0.006). ConclusionAdding the N20 SSEP response results to prior knowledge changed the predicted probability of WLST and survival to discharge in comatose post-arrest patients.

PEITC promotes neurite growth in primary sensory neurons via the miR-17-5p/STAT3/GAP-43 axis

The present study explored a key miRNA that plays a vital role in sciatic nerve conditioning injury promoting repair of injured dorsal column, and validated its function. Microarray analysis revealed miR-17-5p expression decreased sharply at 3, 7 and 14 days in the sciatic nerve conditioning injury group compared with the simple dorsal column lesion group. After miR-17-5p inhibition in DRG neurons, GAP-43 expression was upregulated and neurite growth was increased. STAT3 together with p-STAT3 showed opposite trends with miR-17-5p. MiR-17-5p inhibition extended neurite and upregulated STAT3, p-STAT3 and GAP-43. To further determine a substitution therapy for sciatic nerve conditioning injury, beta-phenethyl isothiocyanate (PEITC), which downregulates miR-17-5p, was assessed. The results showed that treatment with 10 µM PEITC resulted in longest neurite length. Further experiments demonstrated PEITC induced neurite growth by inhibiting miR-17-5p and further upregulating STAT3, p-STAT3 and GAP-43. The somatosensory evoked potential test confirmed similar treatment effects for PEITC, Ad-miRNA-17-5p inhibitor, and sciatic nerve conditioning injury on the dorsal column lesion. In conclusion, the miR-17-5p/STAT3/GAP-43 axis is an indispensable component of sciatic nerve conditioning injury promoting repair of injured dorsal column. PEITC could promote repair of injured dorsal column via the miR-17-5p/STAT3/GAP-43 axis, and could mimic the treatment effect of sciatic nerve conditioning injury.

SSEP in Therapeutic Hypothermia Era.

The reliability of somatosensory evoked potentials (SSEPs) in predicting outcome in comatose survivors of cardiac arrest treated with therapeutic hypothermia (TH) has been questioned. We investigated whether the absence of cortical (N20) responses was a reliable predictor of a nonawakening in the setting of TH. A retrospective review was conducted in cardiac arrest survivors treated with TH admitted to a single tertiary care hospital from April, 2010 to March, 2013 who underwent SSEP testing at various time points after cardiac arrest. N20 responses were categorized as normal, present but abnormal, bilaterally absent, or inadequate for interpretation. Neurologic outcome was assessed at discharge by the Cerebral Performance Category Scale (CPC). Ninety-three SSEP studies were performed in 73 patients. Fourteen patients had absent N20 responses; all had poor outcome (CPC 4-5). Eleven patients had absent N20 s during hypothermia, three of whom had follow-up SSEPs after rewarming and cortical responses remained absent. Fifty-seven patients had N20 peaks identified and had variable outcomes. Evaluation of 1 or more N20 peaks was limited or inadequate in 11.4% of SSEPs performed during the cooling because of artifact. Somatosensory evoked potentials remain a reliable prognostic indicator in patients undergoing TH. The limited sample size of patients who had SSEP performed during TH and repeated after normothermia added to the effect of self-fulfilling prophecy limit the interpretation of the reliability of this testing when performed during cooling. Further prospective, multicenter, large scale studies correlating cortical responses in SSEPs during and after TH are warranted. Technical challenges are commonplace during TH and caution is advised in the interpretation of suboptimal recordings.

Patterns of use of somatosensory-evoked potentials for comatose patients in Canada

PurposeTo measure how frequently somatosensory-evoked potentials (SEPs) are used in comatose patients after traumatic brain injury (TBI) and hypoxic ischemic encephalopathy (HIE), how SEPs contribute to outcome prediction and clinical decision making, and how available they are to clinicians. MethodsA novel factual and scenario-based survey instrument to measure patterns of SEPs use in comatose patients due to HIE or TBI was distributed to critical care, neurology, and neurosurgical physicians across Canada. The analysis was based on 86 completed surveys from specialists in neurology (36), neurosurgery (24), and critical care (22). ResultsMost (73%) of respondents reported that SEPs were available. When provided clinical vignettes, only 36% indicated that they would use them in TBI and 49% would use them in HIE. When respondents ranked the various methods available for establishing prognosis for awakening, SEP was ranked after cerebral blood flow and magnetic resonance imaging. The majority did not accurately estimate chances of awakening when SEP responses were bilaterally absent. ConclusionsThere are significant opportunities to optimize the use of SEPs in comatose patients including standardizing SEP testing and reporting, better communicating results to critical care physicians, and improving the understanding regarding the recommended use and interpretation of these tests.

Kinesiology Taping in Cervical Vertigo Treatment

Introduction: In otoneurological clinical practice, cervical vertigo is one of the most common vestibular disorders. Purpose: The aim of this study was to evaluate the effectiveness of Kinesiology Taping in patients with cervical vertigo syndrome, based on an objective assessment of spinal conduction from the balance system sensory receptor (SEP test), a postural control based on a cranio-corpography (CCG test) and Freyss’ dynamic stabilometry. Methods: The research covered 74 patients. Through medical examination all the patients were diagnosed with vertigo of somatosensory etiology (disturbed somatosensory evoked potentials – SEP on a cervical level) or of mixed etiology (disturbed SEP and vasogenic cervical disorders). Kinesiology Taping, using Strips by Nitto Denko Kinesiology Tape / K-Active Tape, was applied to both groups of patients. Somatosensory evoked potential (SEP) test, craniocorpography (CCG), Freyss’ stabilometry test were performed before and after therapy. Results: The results were compared before and after kinesiotaping in patients and between the patients and control group of healthy subjects. With regard to the SEP test, waves N13, P11 and P27 latency measurement results obtained after rehabilitation did not show any statistically important differences, as compared with the control group. In the case of the CCG examination there was no improvement after rehabilitation. Significant differences were observed on Freyss’ stabilometry under the condition of visual control and comparing the groups of strictly somatosensory and mixed cervical vertigo. Conclusions: In patients with cervical vertigo, the applied Kinesiology Taping therapy did not have an impact on the objectively measured parameters of SEP, but caused the positive effect on balance coordination measured by stabilometry. Patients with solely somatosensory etiology of balance disorders responded better to the taping therapy than patients from the mixed etiology group.

New Insight into the Time-Course of Motor and Sensory System Changes in Pain

BackgroundPain-related interactions between primary motor (M1) and primary sensory (S1) cortex are poorly understood. In particular, the time-course over which S1 processing and corticomotor output are altered in association with muscle pain is unclear. We aimed to examine the temporal profile of altered processing in S1 and altered corticomotor output with finer temporal resolution than has been used previously.MethodsIn 10 healthy individuals we recorded somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) in separate sessions at multiple time-points before, during and immediately after pain induced by hypertonic saline infusion in a hand muscle, and at 15 and 25 minutes follow-up.ResultsParticipants reported an average pain intensity that was less in the session where SEPs were recorded (SEPs: 4.0±1.6; MEPs: 4.9±2.3). In addition, the time taken for pain to return to zero once infusion of hypertonic saline ceased was less for participants in the SEP session (SEPs: 4.7±3.8 mins; MEPs 9.4±7.4 mins). Both SEPs and MEPs began to reduce almost immediately after pain reached 5/10 following hypertonic saline injection and were significantly reduced from baseline by the second (SEPs) and third (MEPs) recording blocks during pain. Both parameters remained suppressed immediately after pain had resolved and at 15 and 25 minutes after the resolution of pain.ConclusionsThese data suggest S1 processing and corticomotor output may be co-modulated in association with muscle pain. Interestingly, this is in contrast to previous observations. This discrepancy may best be explained by an effect of the SEP test stimulus on the corticomotor pathway. This novel finding is critical to consider in experimental design and may be potentially useful to consider as an intervention for the management of pain.

Intrathecal transplantation of autologous adipose-derived mesenchymal stem cells for treating spinal cord injury: A human trial

Context: Spinal cord injury (SCI) can cause irreversible damage to neural tissues. However, there is currently no effective treatment for SCI. The therapeutic potential of adipose-derived mesenchymal stem cells (ADMSCs) has been emerged.Objective: We evaluated the effects and safety of the intrathecal transplantation of autologous ADMSCs in patients with SCI.Participants/Interventions: Fourteen patients with SCI were enrolled (12 for ASIA A, 1 for B, and 1 for D; duration of impairments 3–28 months). Six patients were injured at cervical, 1 at cervico-thoracic, 6 at thoracic, and 1 at lumbar level. Autologous ADMSCs were isolated from lipoaspirates of patients’ subcutaneous fat tissue and 9 × 107 ADMSCs per patient were administered intrathecally through lumbar tapping. MRI, hematological parameters, electrophysiology studies, and ASIA motor/sensory scores were assessed before and after transplantation.Results: ASIA motor scores were improved in 5 patients at 8 months follow-up (1–2 grades at some myotomes). Voluntary anal contraction improvement was seen in 2 patients. ASIA sensory score recovery was seen in 10, although degeneration was seen in 1. In somatosensory evoked potential test, one patient showed median nerve improvement. There was no interval change of MRI between baseline and 8 months post-transplantation. Four adverse events were observed in three patients: urinary tract infection, headache, nausea, and vomiting.Conclusions: Over the 8 months of follow-up, intrathecal transplantation of autologous ADMSCs for SCI was free of serious adverse events, and several patients showed mild improvements in neurological function. Patient selection, dosage, and delivery method of ADMSCs should be investigated further.

Rehabilitation outcome of anoxic-ischaemic encephalopathy survivors with prolonged disorders of consciousness

ObjectivesTo examine the natural clinical course of patients admitted to inpatient neurorehabilitation in a coma, vegetative state (VS), or minimally conscious state (MCS) after anoxic-ischaemic encephalopathy (AIE). MethodsThis is a retrospective cohort study of 113 consecutive patients admitted to a German inpatient neurorehabilitation centre with severe disorders of consciousness (DOC) following AIE due to cardiac arrest over a 6-year period. Functional independence was measured with the Glasgow Outcome Scale (GOS) and recovery of consciousness with the Coma Remission Scale (CRS). Separate binary logistic regression models were used to identify independent predictors for functional and behavioural outcomes. ResultsSeven patients (6.2%) achieved a good functional outcome (GOS 4–5). Five of these showed significant functional improvement within the first 8 weeks. 22 patients (19.5%) recovered consciousness; the last patient began to make significant improvement between weeks 10 and 12.Logistic regression showed that both increasing age and lower admission CRS predicted unfavourable functional outcome and persistent DOC. A longer stay in the ICU also predicted persistent DOC at the end of neurorehabilitation. However, neither malignant somatosensory evoked potential (SEP) test results nor hypothermia treatment on the ICU were outcome predictors in either outcome category. ConclusionEven among severely affected AIE patients arriving at a neurological rehabilitation centre in a DOC, there remains potential for functional and behavioural improvement. However, significant improvements may not begin for up to 3 months post-injury. This study suggests that recovery of consciousness and even a good neurological outcome are possible despite malignant SEP test results.

Differential diagnosis of the complex regional pain syndrome

Differential diagnosis of the complex regional pain syndrome

The Utility of a Forehead-to-Inion Derivation in Recording the Subcortical Far-Field Potential (P14) During Median Nerve Somatosensory-Evoked Potential Testing

American Clinical Neurophysiology Society (ACNS) guidelines recommend recording P14 between an ipsilateral centroparietal electrode (CPi) and a noncephalic reference, typically the contralateral Erb's point (EPc) (American Clinical Neurophysiology Society. Guideline 9D: guidelines on short-latency somatosensory evoked potentials. J Clin Neurophysiol. 2006;23(2):168-179). We investigated the utility of a forehead (Fpz)-to-inion derivation for recording P14. We analyzed 74 median nerve somatosensory-evoked potential (SEP) studies (148 nerves) with bilaterally normal peripheral and central conductions. The presence of an identifiable P14 and its amplitude and latency were assessed in both the CPi-EPc and Fpz-inion derivations. In 7 of the 148 recordings, P14 was not identifiable in either derivation. The P14 was only identifiable in CPi-EPc in 9 recordings, and only identifiable in Fpz-inion in 4 recordings. In the remaining 128 recordings, the mean P14 latency was 13.2 ± 1.1ms in both derivations. The mean P14 amplitude using CPi-EPc was 2.0 ± 0.6µV, significantly larger than that using Fpz-inion, 1.2 ± 0.6µV (P < .001). In conclusion, the CPi-EPc derivation and the Fpz-inion derivation both record the same P14 component, and latency norms based on either derivation are interchangeable. Although the CPi-EPc derivation typically yields a larger and more identifiable P14, occasionally Fpz-inion yields a larger P14, and rarely P14 is only identifiable using Fpz-inion. Thus, recording of the Fpz-inion derivation may be a useful adjunct during median nerve SEP testing.

DOES HYPOTHERMIA INFLUENCE THE PREDICTIVE VALUE OF BILATERAL ABSENT N20 AFTER CARDIAC ARREST?

Leithner et al.1 assessed the median somatosensory evoked potentials (SSEP) in patients treated with hypothermia after cardiac arrest. One of their 36 patients had bilateral absence of N20 potential at day 3 and eventually regained consciousness and recovered normal cognitive function. The remaining 35 patients died without awakening or entered persistent vegetative state. The authors draw the conclusion that bilateral absence of N20 as an outcome predictor needs to be reevaluated, and not used in the decision to stop therapy. There are sparse data on the sole survivor. The patient was a 43-year-old man with alcoholism who developed pneumonia and sepsis, and had asystole for 10 minutes. SSEP testing was not repeated until 18 months later, when N20 responses were intact. There have been 2 previous studies utilizing SSEP as a predictor in comatose patients following hypothermia. Tiainen et al.2 described 3 patients following cardiac arrest treated with hypothermia with absent N20 responses, and 8 normothermic controls with absent …

A new composite midface allotransplantation model with sensory and motor reinnervation

In this study, we extended application of face transplantation model in rat by incorporation of vascularized premaxilla, and nose with infraorbital and facial nerves for evaluation of allotransplanted sensory and motor nerve functional recovery. In group I (n = 3) the dissection technique is studied. In group II (n = 5) isotransplantations were performed. In group III (n = 5) allotransplantations were performed under Cyclosporin A monotherapy. Grafts; composed of nose, lower lip, and premaxilla; were dissected. Infraorbital nerve and facial nerve were included into the transplant. A heterotopic transplantation was performed to inguinal region of recipient. Nerve coaptations were performed between infraorbital-sapheneous nerve and facial-femoral nerve. CT scan, somatosensory-evoked potential testing (SSEP), motor-evoked potential testing (MEP), and microangiography were used for evaluation. All transplants survived indefinitely over 100 days. Microangiography showed preserved vascularization of the graft. Computed tomography revealed vital premaxillary bone segments. SSEP and MEP confirmed recovery of motor and sensory functions and latencies reached 67% of normal infraorbital nerve value and 70% of normal facial nerve value at 100 days post-transplant. We have introduced new midface transplant model of composite midface allograft with sensory and motor units. In this model, motor and sensory functional recovery was confirmed at 100 days post-transplant.

Penis Allotransplantation Model in the Rat

In this study we present the first experimental vascularized penile allogenic transplantation model in the rat. In group 1 (n = 6), the vascular anatomy of the male rat perineal region was determined. In 12 Lewis rats of group 2 (n = 24), the penile composite graft was transplanted as isotransplant by microvascular anastomosis of the pedicle of the penis to the saphenous vessels and in another 12 Lewis rats of group 2, penile composite graft was transplanted without vascular anastomosis. In group 3 (n = 12), penis composite graft was transplanted from 6 Lewis-Brown-Norway donors to 6 Lewis recipients under CsA immunosuppression. Direct observation, somatosensory evoked potential test, histologic examination and microangiography were used to assess the viability of the transplants. All vascularized isotransplants and allotransplants survived over 200 days (still under observation) whereas all the nonvascularized grafts were necrosed at 7 days posttransplant. In this study the new penile allograft transplantation model in the rat was developed and a new method of blood supply to a vascularized composite tissue with directly artery-to-corpus spongiosum anastomosis was introduced.

Anoxic–Ischemic Encephalopathy: Clinical and Electrophysiological Associations With Outcome

Prognostic determination of patients in coma after resuscitation from cardiac arrest is both common and difficult. We explored clinical and electrophysiological testing to determine their associations with favorable and poor outcomes. We studied 75 comatose patients resuscitated from cardiac arrest, excluding those who were brain dead or continuously sedated; none received hypothermia therapy. Clinical examinations were performed on day 1. The following proportions recovered awareness: 2 of 18 patients with absent pupillary reflexes; 18 of 57 with preserved pupillary reflexes (p = 0.08); 2 of 32 with absent corneal reflexes; 16 of 43 with preserved corneal reflexes (p = 0.001); 0 of 15 with absent oculovestibular reflexes; and 8 of 29 with preserved oculovestibular reflexes (p < 0.037). Purposeful movements were associated with a high probability of recovery, whereas other categories were unfavorable. Other categories of motor response were associated with an increased proportion of those who died without recovering awareness, but each category had some survivors. Somatosensory evoked potentials (SSEPs) were recorded from 47 patients. One of 21 patients with loss of the N20 component survived, compared with survival of 11 of 26 patients in whom it was present (p = 0.003). All 5 patients with preserved N70 responses recovered awareness in a subgroup of 33 patients. Sixteen of 22 subjects with mild electroencephalogram (EEG) abnormalities recovered consciousness, compared with the survival of 3 of 50 patients with malignant EEG patterns (p = 0.0000001). Combining SSEP with EEG findings produced even greater predictive value. It seems unlikely that any single test will prove to have 100% predictive value for outcome; further studies combining clinical, EEG, and SSEP testing are warranted.