Efficacy of MR Neurography of Peripheral Trigeminal Nerves: Correlation of Sunderland Grade versus Neurosensory Testing.

BACKGROUND AND PURPOSE: The current reference standard of diagnosis for peripheral trigeminal neuropathies (PTN) is clinical neurosensory testing (NST). MR neurography (MRN) is useful for PTN injury diagnosis, but it has only been studied in small case series. The aim of this study was to evaluate the agreement of Sunderland grades of nerve injury on MRN and NST by using surgical findings and final diagnoses as reference standards. MATERIALS AND METHODS: A total of 297 patient records with a chief complaint of PTN neuralgia were identified from the university database, and 70 patients with confirmed NST and MRN findings who underwent surgical nerve repair were included in the analysis. Cohen weighted kappa was used to calculate the strength of the agreement between the 3 modalities. RESULTS: There were 19 men and 51 women, with a mean age of 39.6 years and a standard deviation of 16.9 years. Most (51/70, 73%) injuries resulted from tooth extractions and implants. MRN injury grades agreed with surgical findings in 84.09% (37/44) of cases, and NST injury grades agreed with surgical findings in 74.19% (23/31) of cases. MRN and NST both showed similar agreement with surgery for grades I to III (70% and 71.43%). However, MRN showed a higher rate of agreement with surgery (88.24%) for injury grades IV and V than did NST (75%). CONCLUSIONS: MRN can objectively improve preoperative planning in patients with higher-grade nerve injuries.

Utility of MR Neurography for the Evaluation of Peripheral Trigeminal Neuropathies in the Postoperative Period.

Peripheral trigeminal neuropathies are assessed by MR neurography for presurgical mapping. In this clinical report, we aimed to understand the utility of MR neurography following nerve-repair procedures. We hypothesized that postoperative MR neurography assists in determining nerve integrity, and worsening MR neurography findings will corroborate poor patient outcomes. Ten patients with peripheral trigeminal neuropathy were retrospectively identified after nerve-repair procedures, with postsurgical MR neurography performed from July 2015 to September 2023. Postsurgical MR neurography findings were graded as per postintervention category and subcategories of the Neuropathy Score Reporting and Data System (NS-RADS). Descriptive statistics of demographics, inciting injury, injury severity, NS-RADS scoring, and clinical outcomes were obtained. There were 6 women and 4 men (age range, 25-73 years). Most injuries resulted from third molar removals (8/10), with an average time from the inciting event to nerve-repair surgery of 6.1 (SD, 4.6) months. In Neuropathy Score Reporting and Data System-Injury (NS-RADS I), NS-RADS I-4 injuries (neuroma in continuity) were found in 8/10 patients, and NS-RADS I-5 injuries were found in the remaining patients, all confirmed at surgery. Surgeries performed included microdissection with neurolysis, neuroma excision, and nerve allograft with Axoguard protection. Three patients with expected postsurgical MR neurography findings experienced either partial improvement or complete symptom resolution, while among 7 patient with persistent or recurrent neuropathy on postsurgical MR neurography, one demonstrated partial improvement of sensation, pain, and taste and one experienced only pain improvement; the remaining 5 patients demonstrated no improvement. Postsurgical MR neurography consistently coincided with clinical outcomes related to pain, sensation, and lip biting and speech challenges. Lip biting and speech challenges were most amenable to recovery, even with evidence of persistent nerve pathology on postsurgical MR neurography.

Does Immediate Long-Span Nerve Allograft Reconstruction Affect the Incidence of Chronic Postsurgical and Neuropathic Pain in the Reconstructed Mandible Following Resection for Benign and Malignant Disease.

BACKGROUND: Peripheral nerve injury can lead to chronic postsurgical pain (CPSP) and neuropathic pain following major surgery. PURPOSE: Determine in patients undergoing ablative mandibular operations with transection of the trigeminal nerve: do those who undergo immediate repair, when compared to those whose nerves are not repaired, have a decreased or increased risk for CPSP or post-traumatic trigeminal neuropathic pain (PTTNp)? STUDY DESIGN, SETTING, SAMPLE: A multisite, retrospective cohort of patients who underwent resection of the mandible for benign or malignant disease with either no repair or immediate repair of the intentionally transected trigeminal nerve with a long-span nerve allograft were analyzed for the presence or absence of CPSP and PTTNp at 6 months. PREDICTOR VARIABLE: The primary predictor was the immediate repair or no repair of the trigeminal nerve. MAIN OUTCOME VARIABLE: The primary outcome was the presence or absence of CPSP and PTTNp at 6 months postsurgery. COVARIATES: There were 13 covariate variables, including age, sex, ethnicity, nerve injury, type of PTTNp, malignant or benign pathology and subtypes of each, use of radiation or chemotherapy, treatment of transected nerve end, longest follow-up time, pain scale, and onset of pain. ANALYSES: Two-tailed Student's t test and Welch's t test were performed on mean scores and post hoc logistics and linear regression modeling were performed when indicated. The confidence level for statistical significance was P value <.05. RESULTS: There were 103 and 94 subjects in the immediate and no-repair groups, respectively. The incidence of CPSP in the no-repair group was 22.3% and PTTNp was 2.12%, while there was 3.8% CPSP and 0% PTTNp in the repair group, which was statistically significant (P = <.001). Logistic regression modeling showed a statistically significant inverse relationship between the immediate repair and the incidence of CPSP/PTTNp with an odds ratio of 0.43, 95% confidence interval 0.18 to 1.01, P = .05. Greater age, malignant pathology, and chemo/radiation treatments were covariates found more frequently in the no repair group. CONCLUSION AND RELEVANCE: Immediate repair of an intentionally transected trigeminal nerve with a long-span nerve allograft during resection of the mandible for both benign and malignant disease appears to reduce CPSP and possibly eliminate the development of PTTNp.

Is Presurgical Pain Intensity Related to Postoperative Recurrence of Post-Traumatic Trigeminal Neuropathic Pain?

PURPOSE: Post-traumatic trigeminal neuropathic pain (PTTNp) is a challenging condition to treat, and equally as challenging is the identification of surgical outcome variables to guide treatment. The study purpose was to determine if preoperative pain intensity was related to postoperative recurrence of PTTNp. MATERIALS AND METHODS: This retrospective cohort study assessed subjects at a single institution with preoperative PTTNp of either the lingual or inferior alveolar nerves who underwent elective microneurosurgery. Two cohorts were established as follows: No PTTNp at 6 months (group 1); presence of PTTNp at 6 months (group 2). The primary predictor variable was the preoperative visual analog scale (VAS) score. The primary outcome variable was PTTNp (recurrence or no recurrence at 6 months). The demographic and injury characteristics of the groups were compared to assess whether they were similar using Wilcoxon rank analysis. Two-tailed Student's t-test was performed to analyze the difference in preoperative mean VAS scores. Multivariate multiple linear regression models were used to determine the association between the covariates on the outcomes of the primary predictor variable and the primary outcome variable. A P value of <.05 was considered statistically significant. RESULTS: Forty-eight patients were included in the final analysis. There were 20 patients with no pain at 6 months and 28 with recurrence at 6 months following surgery. There was a significant difference in mean preoperative pain intensity between the two groups (P value .04). The mean preoperative VAS score in group 1 was 6.31 (standard deviation, 2.65), while the mean preoperative VAS score in group 2 was 7.75 (standard deviation, 1.95). Regression analysis showed that one covariate, the type of nerve injured, explained some variability of preoperative VAS score, but by only 16% (P value .005). Regression analysis also showed that two covariates, Sunderland classification and time to surgery, explained some of the variability of PTTNp at 6 months, by approximately 30% (P value .001). CONCLUSION: This study showed that presurgical pain intensity level was related to postoperative recurrence in the surgical treatment of PTTNp. In patients with recurrence, the preoperative pain intensity was higher. Other factors, including time interval from injury to surgery, were also related to recurrence.

How Does Changing the Time to Surgery Affect the Recurrence of Post-Traumatic Trigeminal Neuropathic Pain.

PURPOSE: The recurrence of post-traumatic trigeminal neuropathic pain (PTTNp) following peripheral microneurosurgery continues to be poorly understood. The objective of this study was to determine if the time from injury to surgery of the trigeminal nerve in patients with PTTNp affected the recurrence of PTTNp following surgery. PATIENTS AND METHODS: A retrospective cohort of patients with PTTNp prior to trigeminal nerve surgery at a single institute was analyzed for the presence or absence of PTTNp at 6 months postsurgery. The primary predictor was the time from injury to surgical treatment and the primary outcome was the presence or absence of PTTNp using subjective and objective neurosensory testing at 6 months. Four groups were predefined to evaluate the effect of time to surgery: Group 1 (0 to 100 days), Group 2 (101 to 200 days), Group 3 (201 to 300 days), and Group 4 (> 300 days). Repeated measures analysis of variance was used to assess differences in the presence or absence of PTTNp among groups. If a statistical difference was found, a post hoc Tukey-Kramer test was performed. RESULTS: Sixty of 63 eligible patients met inclusion and exclusion criteria with end points at 6 months. The weighted mean PTTNp score in Group 1 was 1.6 ± 0.32, Group 2 was 1.61 ± 0.18, Group 3 was 1.3 ± 0.29, and Group 4 was 1 ± 0.0. There was a statistically significant difference in the primary outcome among the groups based on time from injury to repair (P = .0002). The between-group differences were significant for Group 1 and 3 and 4 and between Group 2 and 3 and 4 (P < .01). Within the 4 cohorts, the percentage of patients with PTTNp before surgery with no neuropathic pain at the 6-month follow-up was 41.6%. However, between the 4 cohorts, when the time to surgery was 200 days or less, the percentage of patients with PTTNp before surgery with no neuropathic pain at the 6-month follow-up was more than 60%. CONCLUSIONS: Time from injury to surgery appears to have an effect on the recurrence of PTTNp. Best outcomes are associated with operative interventions within 200 days of the injury.

Post-traumatic Trigeminal Neuropathic Pain: Factors Affecting Surgical Treatment Outcomes.

Post-traumatic trigeminal neuropathic pain (PTTNp) is a painful condition that may result from injury to the sensory division of the trigeminal nerve. Treatment of this condition is challenging and consensus on treatment to resolve neuropathic pain has yet to be standardized. Equally as challenging is the identification of surgical outcome variables to guide surgical treatment of PTTNp. This is partly due to the variability in pain characteristics, severity of nerve injury, location, and duration from injury to surgery. In those with neuropathic pain prior to microsurgical intervention, the incidence of neuropathic pain after microsurgical intervention is 67%. It is unclear why nerve repair surgery is effective in resolving or decreasing neuropathic pain in some patients, whereas it has no effect on pain relief in others. Psychological, medical, and age-related factors have been identified as risk factors for developing chronic post-surgical pain due to post-traumatic neuropathic pain. Two factors: injury to surgery time and preoperative visual analog scale score have recently been identified as variables that influence surgical outcomes in the treatment of PTTNp.

Arthrocentesis versus nonsurgical methods in the management of temporomandibular joint closed lock and pain: a double-blind randomized controlled trial.

OBJECTIVE: The present double-blind randomized clinical trial aimed to compare the efficacy of conservative treatment and articular lavage, either alone or combined, to reduce joint pain and improve mandibular opening. STUDY DESIGN: The sample consisted of patients presenting with limited mouth opening and joint pain. The diagnosis was made according to the diagnostic criteria for temporomandibular disorders guideline and confirmed by magnetic resonance imaging. Sixty patients were selected and randomly allocated to 4 groups of 15 patients each with different treatments: group A (conservative), group B (conservative + medication), group C (arthrocentesis), and group D (arthrocentesis + medication). The groups were compared in terms of maximal interincisal opening and pain. RESULTS: The average age of the patients was 34.17 ± 13.1 years, 88.1% were women, 72.9% had internal derangement, 54% had joint sounds, and 55.9% presented with locking. Clinical improvement was noted in all parameters compared with baseline in all groups (P < .005), but no significant differences were observed when the groups were compared (P > .05). CONCLUSIONS: Both arthrocentesis and conservative modalities were efficient treatments to reduce joint pain and increase mandibular opening.

Does Presurgical Magnetic Resonance Neurography Predict Surgical Gap Size in Trigeminal Class IV and V Injuries?

PURPOSE: The accuracy of magnetic resonance neurography (MRN) for quantitative assessment of nerve injury gap is unknown. We tested the hypothesis that presurgical MRN predicts the final surgical gap size after neuroma resection at the time of surgery. MATERIALS AND METHODS: This was a retrospective, single-blinded, nonrandomized cohort study on 43 patients with Sunderland Class IV and V injuries of the inferior alveolar (IAN) or the lingual nerve (LN). The MRN maxillofacial protocol was performed on a 3T scanner and was read by 2 musculoskeletal radiologists to determine the maximum size of neuroma and the abnormal nerve segment. Two independent variables were recorded during surgery: 1) the length of neuroma from histologic specimens since only 9 of the 43 neuroma size measurements were accurately measureable at the time of surgery; and 2) the length of nerve gap size after the neuroma was removed and normal fascicles were identified. RESULTS: There were 7 IAN and 36 LN cases analyzed. The mean time in months from injury to MRN was 6.97 ± 9.18 and MRN to surgery was 1.21 ± 1.4. The mean length of the neuroma at surgery was 7.22 ± 2.78 mm and mean nerve gap size was 12.02 ± 4.41 mm. Intraclass coefficient (ICC) agreement was fair for abnormal nerve thickness and neuroma length (ICC = 0.28, 0.39) while it was moderate for neuroma thickness and abnormal nerve length (0.50, 0.59). There was no significant correlation between MRN based measurements and surgical gap size for both readers (P > .05). CONCLUSIONS: Abnormal nerve and neuromas of the peripheral trigeminal nerve as identified on MRN imaging demonstrates no correlation of the assessed MRN findings with the final surgical gap after neuroma removal.

Trigeminal Nerve Repair: Is the Trigeminocardiac Reflex a Concern?

PURPOSE: Our hypothesis is that direct manipulation of the third and second divisions of the trigeminal nerve during microneurosurgery does not affect the incidence of trigeminocardiac reflex (TCR). The purpose of this paper was to analyze the incidence of TCR events during microneurosurgery involving the second and third divisions of the trigeminal nerve. MATERIALS AND METHODS: This was a retrospective cohort study of 94 patients who underwent nerve repair of the second and third divisions of the trigeminal nerve, between July 2014 and February 2021 by a single surgeon (J. Z.). The independent variables were the trigeminal nerve branch injured, the laterality of the trigeminal nerve injury, the Sunderland classification, the ASA classification, the intraoperative narcotic(s) used, and the depth of anesthesia. The dependent variables included the occurrence of intraoperative hypercapnia, hypoxia, and TCR event. Since the data was retrospective and categorical in nature, χ2 analysis was performed initially. RESULTS: None of the patients in this retrospective cohort demonstrated intraoperative hypercapnia, hypoxia or TCR events. Initial χ2 calculation was performed for the dependent variables with the trigeminal nerve groups (IAN, LN, and ION). The χ2 calculation [χ2 (1, n = 101)] was 0.2235. The P-value was .6364. Since there was no statistical significance found, there was no further analysis of surgical and anesthesia independent variables in the data collection. CONCLUSIONS: The zero incidence of TCR in a large number of patients provides strong evidence supporting the rejection of the hypothesis that TCR can occur during the surgical repair of peripheral trigeminal nerves.

How Many Oral Surgeons Does It Take to Classify a Nerve Injury?

PURPOSE: There is inconsistency in clinical grading of peripheral trigeminal nerve (TN5) injuries that impact patient care. The study goal is to assess the current status of evaluation and classification of TN5 injuries by oral and maxillofacial surgeons (OMSs). PATIENTS AND METHODS: A cross-sectional study design used an electronic survey to 100 selected OMSs to determine their clinical TN5 injury practice, including neurosensory testing, confidence level with current protocols, and evaluation and treatment of a hypothetical TN5 injury case. The target sample was enhanced to reduce type 2 error, assuming prior experience in the diagnosis and management of TN5 injuries. RESULTS: The sample was composed of 90 respondents. Nerve injury classification systems used by OMSs include Seddon (44%), Sunderland (70%), and Medical Research Council Scale (31%). Neurosensory testing protocols varied considerably among survey respondents. A sample case for Medical Research Council Scale grading produced inconsistent and inaccurate results. There was no consensus on TN5 injury management, and recommendations for timely nerve repair varied from 1 month to up to 1 year after injury. Half of the respondents stated that OMSs are not adequately prepared to assess inferior alveolar/lingual nerve injuries, and most oral-maxillofacial surgery respondents evaluate fewer than 10 TN5 injuries each year. Most OMSs (92%) have had a temporary inferior alveolar/lingual nerve injury, while 54% have had a permanent injury; of which, 21% required microsurgical repair. The majority of OMSs (74%) believed that a uniform TN5 injury classification system is needed. CONCLUSIONS: Within the oral-maxillofacial surgery target group experienced in evaluation of TN5 injuries, respondents do not feel confident in the assessment of these injuries. There is inconsistency in evaluation methods, and there is agreement that a unified classification system is needed for more efficient patient evaluation and reporting of outcomes in the literature. The Medical Research Council Scale and clinical neurosensory testing is preferred for evaluation of TN5 injuries.

Trigeminocardiac Reflex Induced by Maxillary Nerve Stimulation during Sphenopalatine Ganglion Implantation: A Case Series.

BACKGROUND: The trigeminocardiac reflex (TCR) is a brainstem reflex following stimulation of the trigeminal nerve, resulting in bradycardia, asystole and hypotension. It has been described in maxillofacial and craniofacial surgeries. This case series highlights TCR events occurring during sphenopalatine ganglion (SPJ) neurostimulator implantation as part of the Pathway CH-2 clinical trial "Sphenopalatine ganglion Stimulation for Treatment of Chronic Cluster Headache". METHODS: This is a case series discussing sphenopalatine ganglion neurostimulator implantation in the pterygopalatine fossa as treatment for intractable cluster headaches. Eight cases are discussed with three demonstrating TCR events. All cases received remifentanil and desflurane for anesthetic maintenance. RESULTS: Each patient with a TCR event experienced severe bradycardia. In two cases, TCR resolved with removal of the introducer, while the third case's TCR event resolved with both anticholinergic treatment and surgical stimulation cessation. CONCLUSION: Each TCR event occurred before stimulation of the fixed introducer device, suggesting the cause for the TCR events was mechanical in origin. Due to heightened concern for further TCR events, all subsequent cases had pre-anesthesia external pacing pads placed. Resolution can occur with cessation of surgical manipulation and/or anticholinergic treatment. Management of TCR events requires communication between surgical teams and anesthesia providers, especially during sphenopalatine ganglion implantation when maxillary nerve stimulation is possible.

Nerve Grafting in Head and Neck Reconstruction.

In head and neck reconstructive surgery, especially of the mandible, the long-span processed nerve allograft (PNA) is a technological advancement that provides improved quality of life for patients who require ablative surgery by allowing for functional sensory recovery (FSR) in the majority of patients treated with immediate reconstruction. Recently published clinical prospective and retrospective multisite controlled cohort studies of immediate nerve reconstruction at the time of ablative surgery, including pediatric patient populations, were reviewed for valid and predictable outcomes of FSR following the reconstruction of the inferior alveolar nerve using > 5-cm PNA allografts. Both adult and pediatric patients demonstrate high percentages of FSR within 1 year. Pediatric patients demonstrate robust recovery with 100% reaching FSR within 1 year, whereas 89% of adults achieved FSR during the same time span; the pediatric patient population reached FSR earlier when compared with adults. Control, nonallograft nerve repair patients never achieved FSR, reaching only S2 levels in both adults and pediatric groups. There were no adverse events; in fact, no patients demonstrated the occurrence of neuropathic pain when the nerve repair was performed immediately in contrast to delayed repair states. Long-span (> 5-cm) nerve allografts provide FSR in pediatric patients and the majority of adult patients and should be used in patients who require ablation of the mandible for head and neck reconstruction.

Does Immediate Inferior Alveolar Nerve Allograft Reconstruction Result in Functional Sensory Recovery in Pediatric Patients?

PURPOSE: Ablative mandibular resection may result in neurosensory loss and decreased quality-of-life, yet nerve reconstruction is not performed routinely for various reasons, including increased operative time. This study aimed to determine whether immediate inferior alveolar nerve (IAN) allograft reconstruction provides functional sensory recovery (FSR) in the pediatric age group. PATIENTS AND METHODS: This multicenter retrospective cohort study included pediatric patients who underwent mandibular resection with IAN discontinuity and a nerve allograft greater than 45 mm. A positive control group also was included, comprising pediatric patients who underwent mandibular resection without nerve reconstruction. The primary predictor variable was the use of a nerve allograft; a secondary variable was the time to achieve FSR using the Medical Research Council Scale. Comparisons were made to historical adult data. Statistical analysis of the comparison of neurosensory outcomes over time was measured by weighted values, repeated-measures analysis of variance, and the McNemar test. RESULTS: The study group consisted of 32 patients, 18 in the graft group and 14 in the non-graft group, without significant differences in age, gender, or nerve gap length. By 1 year, FSR was achieved in 100% in the study group and 0% in the control group (P < .00001). The median time to FSR was 75 days in the study group and 110 days in the historical adult study group. In comparison to historical adult data, there was a significant difference at 1 year, with adults at 87% FSR (P = .01562). CONCLUSIONS: Long-span nerve allografts were effective in restoring sensation to the lip and chin in pediatric patients, with 100% reaching FSR, whereas no patients without nerve reconstruction achieved FSR. Pediatric patients recovered to a higher level of FSR than adults at 1 year. Immediate IAN reconstruction in pediatric patients should be considered strongly when the mandible requires resection with sacrifice of the IAN.

Retrieval of an Intracranially Migrated Dental Injection Needle Through the Foramen Ovale: 2-Dimensional Operative Video.

Dental injection needle migration is a rare complication of orthodontal procedures. When these needles fracture, they typically dislodge into the cervical space or the facial musculature. Migration into the cranial vault is difficult because of the obstacle created by the skull base. We report a rare case of intracranial migration of an anesthetic injection needle through the foramen ovale. A 59-yr-old man underwent the extraction of a right maxillary molar. The distal end of a 25-gauge injection needle broke into his pterygoid musculature, causing him pain while chewing. Vascular imaging obtained after a computed tomography scan of his face showed that the needle had migrated, potentially because of his efforts of mastication, and had traversed the foramen ovale into the middle cranial fossa. The patient started experiencing intermittent right facial numbness, likely due to compression or injury to the right trigeminal nerve. Our oral and maxillofacial colleagues did not believe that the needle could be retrieved from its facial end. The patient elected to undergo the recovery of the needle through a craniotomy given the fact that the object was contaminated and because he was becoming increasingly symptomatic. A right pterional craniotomy was planned. Extradural dissection was performed until the dura going into the foramen ovale was revealed. We could feel the metallic needle under the dural sheath of the trigeminal nerve. The dura was opened sharply directly over the needle. We then proceeded to mobilize the needle into the face, and then pulled it out completely through the craniotomy to avoid injury to the temporal lobe. The patient recovered well and was asymptomatic at the time of discharge. This case report was written in compliance with our institutional ethical review board. Institutional review board (IRB) approval and patient consent were waived in light of the retrospective and deidentified nature of the data presented in accordance with the University of Texas Southwestern (UTSW) IRB.

Safety and efficacy of sphenopalatine ganglion stimulation for chronic cluster headache: a double-blind, randomised controlled trial.

BACKGROUND: Chronic cluster headache is the most disabling form of cluster headache. The mainstay of treatment is attack prevention, but the available management options have little efficacy and are associated with substantial side-effects. In this study, we aimed to assess the safety and efficacy of sphenopalatine ganglion stimulation for treatment of chronic cluster headache. METHODS: We did a randomised, sham-controlled, parallel group, double-blind, safety and efficacy study at 21 headache centres in the USA. We recruited patients aged 22 years or older with chronic cluster headache, who reported a minimum of four cluster headache attacks per week that were unsuccessfully controlled by preventive treatments. Participants were randomly assigned (1:1) via an online adaptive randomisation procedure to either stimulation of the sphenopalatine ganglion or a sham control that delivered a cutaneous electrical stimulation. Patients and the clinical evaluator and surgeon were masked to group assignment. The primary efficacy endpoint, which was analysed with weighted generalised estimated equation logistic regression models, was the difference between groups in the proportion of stimulation-treated ipsilateral cluster attacks for which relief from pain was achieved 15 min after the start of stimulation without the use of acute drugs before that timepoint. Efficacy analyses were done in all patients who were implanted with a device and provided data for at least one treated attack during the 4-week experimental phase. Safety was assessed in all patients undergoing an implantation procedure up to the end of the open-label phase of the study, which followed the experimental phase. This trial is registered with ClinicalTrials.gov, number NCT02168764. FINDINGS: Between July 9, 2014, and Feb 14, 2017, 93 patients were enrolled and randomly assigned, 45 to the sphenopalatine ganglion stimulation group and 48 to the control group. 36 patients in the sphenopalatine ganglion stimulation group and 40 in the control group had at least one attack during the experimental phase and were included in efficacy analyses. The proportion of attacks for which pain relief was experienced at 15 min was 62·46% (95% CI 49·15-74·12) in the sphenopalatine ganglion stimulation group versus 38·87% (28·60-50·25) in the control group (odds ratio 2·62 [95% CI 1·28-5·34]; p=0·008). Nine serious adverse events were reported by the end of the open-label phase. Three of these serious adverse events were related to the implantation procedure (aspiration during intubation, nausea and vomiting, and venous injury or compromise). A fourth serious adverse event was an infection that was attributed to both the stimulation device and the implantation procedure. The other five serious adverse events were unrelated. There were no unanticipated serious adverse events. INTERPRETATION: Sphenopalatine ganglion stimulation seems efficacious and is well tolerated, and potentially offers an alternative approach to the treatment of chronic cluster headache. Further research is need to clarify its place in clinical practice. FUNDING: Autonomic Technologies.

Prevention of Opioid-Induced Nausea and Vomiting During Treatment of Moderate to Severe Acute Pain: A Randomized Placebo-Controlled Trial Comparing CL-108 (Hydrocodone 7.5 mg/Acetaminophen 325 mg/Rapid-Release, Low-Dose Promethazine 12.5 mg) with Conventional Hydrocodone 7.5 mg/Acetaminophen 325 mg.

OBJECTIVES: To evaluate the prevention of opioid-induced nausea and vomiting (OINV) and the relief of moderate to severe acute pain by CL-108, a novel drug combining a low-dose antiemetic (rapid-release promethazine 12.5 mg) with hydrocodone 7.5 mg/acetaminophen 325 mg (HC/APAP) was used. METHODS: This was a multicenter, randomized, double-blind, placebo- and active-controlled multidose study. After surgical extraction of two or more impacted third molar teeth (including at least one mandibular impaction), 466 patients with moderate to severe pain (measured on a categorical pain intensity scale [PI-CAT]) were randomized to CL-108, HC/APAP, or placebo. Over the next 24 hours, patients used the PI-CAT to assess pain at regular intervals whereas nausea, vomiting, and other opioid-related side effects were also assessed prospectively. Study medications were taken every four to six hours as needed; supplemental rescue analgesic and antiemetic medications were permitted. Co-primary end points were the incidence of OINV and the time-weighted sum of pain intensity differences over 24 hours (SPID24). RESULTS: Relative to HC/APAP treatment alone, CL-108 treatment reduced OINV by 64% (P < 0.001). Treatment with CL-108 significantly reduced pain intensity compared with placebo (SPID24 = 16.2 vs 3.5, P < 0.001). There were no unexpected or serious adverse events. CONCLUSIONS: CL-108 is a safe and effective combination analgesic/antiemetic for the prevention of OINV during treatment of moderate to severe acute pain.

MR Neurographic Evaluation of Facial and Neck Pain: Normal and Abnormal Craniospinal Nerves below the Skull Base.

Cranial nerve disease outside the skull base is a common cause of facial and/or neck pain, which causes significant disability for patients and frustration for clinicians. Neuropathy in this region can be traumatic, idiopathic, or iatrogenic secondary to dental and surgical procedures. MR neurography is a modification of conventional MRI techniques dedicated to evaluation of peripheral nerves and is being increasingly used for imaging of peripheral neuropathies at various sites in the body. MR neurography facilitates assessment of different causes of craniofacial pain and cranial nerves and allows elegant depiction of a multitude of regional neuropathies. This article discusses the anatomy, pathologic conditions, and imaging findings of the commonly implicated but difficult to image infratentorial nerves, such as the peripheral trigeminal nerve and its branches, facial nerve, glossopharyngeal nerve, vagus nerve, hypoglossal nerve, and greater and lesser occipital nerves. ©RSNA, 2018.

Magnetic Resonance Neurography of Traumatic and Nontraumatic Peripheral Trigeminal Neuropathies.

PURPOSE: The clinical neurosensory testing (NST) is currently the reference standard for the diagnosis of traumatic and nontraumatic peripheral trigeminal neuropathies (PTNs), but exhibits both false-positive and false-negative results compared with surgical findings and frequently results in treatment decision delays. We tested the hypothesis that magnetic resonance neurography (MRN) of PTNs can serve as a diagnostic modality by correlating the NST, MRN, and surgical findings. MATERIALS AND METHODS: Sixty patients with traumatic and nontraumatic PTN of varying etiologies and Sunderland classifications underwent NST, followed by MRN using 1.5T and 3.0T scanners. The protocol included 2-dimensional and 3-dimensional (3D) imaging, including diffusion imaging and isotropic 3D PSIF. The MRN findings were read by 2 readers in consensus with the clinical findings but without knowing the side of abnormality. The MRN results were summarized using the Sunderland classification. In 26 patients, surgery was performed, and the Sunderland classification was assigned using the surgical photographs. Agreement between the MRN findings and NST/surgical classification was evaluated using kappa statistics. Pearson's correlation coefficient was used to assess the correlation between continuous measurements of MRN/NST and surgical classification. RESULTS: Of the 60 patients, 19 males and 41 females, mean age 41 years (range 12 to 75), with 54 complaints of altered sensation of the lip, chin, or tongue, including 16 with neuropathic pain and 4 with no neurosensory complaint, were included. Third molar surgery (n = 29) represented the most common cause of traumatic PTN. Assuming 1 nerve abnormality per patient, the lower class was accepted, a kappa of 0.57 was observed between the MRN and NST classification. A kappa of 0.5 was found between MRN and surgical findings with a Pearson correlation coefficient of 0.67. CONCLUSIONS: MRN anatomically maps PTNs and stratifies the nerve injury and neuropathies with moderate to good agreement with NST and surgical findings for clinical use.