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.

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.

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.

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.

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.

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.

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.

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.

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.

A Case-and-Control, Multisite, Positive Controlled, Prospective Study of the Safety and Effectiveness of Immediate Inferior Alveolar Nerve Processed Nerve Allograft Reconstruction With Ablation of the Mandible for Benign Pathology.

PURPOSE: This study determined whether immediate reconstruction of the inferior alveolar nerve with a long (>4.5 cm) processed nerve allograft (PNA) in conjunction with simultaneous ablation and reconstruction of the mandible would be effective in safely restoring subjective sensation and achieving functional sensory recovery. MATERIALS AND METHODS: Patients (5 to 70 yr old) requiring resection of the unilateral or bilateral mandible for benign pathology were included. The graft had to be longer than 4.5 cm. Results of sensory nerve tests and 3 different surveys (Direct Path, Numerical Rating Scale, Word Choice) were collected before surgery and at 3, 6, and 12 months after surgery. Safety data were recorded. RESULTS: Twenty-six patients participated in this study. Three patients served as positive controls (no nerve repair). Five in the repair group and 1 in the positive control group were lost to follow-up. Data during a 1-year period were collected on 18 patients (7 male and 11 female; mean age, 26.4 yr; range, 10 to 64 yr). The mean length of the PNA was 62.7 mm (range, 45 to 70 mm). Seventeen of 18 patients had S4 sensory scores preoperatively and the postoperative score was S4 at 3 months in 3, at 6 months in 3, and at 1 year in 12. Scores for positive control patients never exceeded S2. Numerical rating scales and word choices were not statistically different from presurgical scores at 6 and 12 months. There were no adverse events. CONCLUSIONS: The PNA is safe and effective when immediately inserted with resection and reconstruction of the mandible: 90% of patients achieved functional sensory recovery and reported similar sensations to preoperative subjective values.

Magnetic resonance neurography in the management of peripheral trigeminal neuropathy: experience in a tertiary care centre.

OBJECTIVE: This tertiary care experience examines the utility of magnetic resonance neurography (MRN) in the management of peripheral trigeminal neuropathies. MATERIALS AND METHODS: Seventeen patients with clinically suspected peripheral trigeminal neuropathies (inferior alveolar nerve and lingual nerve) were imaged uniformly with 1.5-T examinations. MRN results were correlated with clinical and surgical findings in operated patients and the impact on clinical management was assessed. RESULTS: Clinical findings included pain (14/17), sensory changes (15/17), motor changes (2/17) and palpable masses (3/17). Inciting events included prior dental surgery (12/17), trauma (1/17) and idiopathic incidents (4/17). Non-affected side nerves and trigeminal nerves in the intracranial and skull base course were normal in all cases. Final diagnoses on affected sides were nerve inflammation (4/17), neuroma in continuity (2/17), LN transection (1/17), scar entrapment (3/17), infectious granuloma (1/17), low-grade injuries (3/17) and no abnormality (3/17). Associated submandibular gland and sublingual gland oedema-like changes were seen in 3/17 cases because of parasympathetic effects. Moderate-to-excellent MRN-surgical correlation was seen in operated (8/17) patients, and neuroma and nerve transection were prospectively identified in all cases. CONCLUSION: MRN is useful for the diagnostic work-up of suspected peripheral trigeminal neuropathy patients with significant impact on clinical management and moderate-to-excellent correlation with intra-operative findings. KEY POINTS: • MRN substantially impacts diagnostic thinking and management in peripheral trigeminal neuropathy. • MRN has moderate-to-excellent correlation with intra-operative findings. • MRN should be considered in pre-surgical planning of peripheral trigeminal neuropathy subjects.

Factors Determining Outcome After Trigeminal Nerve Surgery for Neuropathic Pain.

PURPOSE: Most patients who seek relief from trigeminal neuropathic pain by trigeminal microneurosurgery techniques do not show permanent pain relief after surgery. However, a small number of patients have permanent relief after surgery. The objective of this study was to determine factors that might be associated with the resolution, decrease, or recurrence of neuropathic pain after trigeminal nerve surgery in those patients who present with neuropathic pain before surgery. PATIENTS AND METHODS: An ambispective study design was used to assess patients who underwent trigeminal nerve repair of the inferior alveolar and lingual nerve who had documented neuropathic pain before surgery from 2006 through 2014. The primary endpoint was the difference in pain intensity at 3, 6, and 12 months after surgery compared with presurgical intensity levels. Explanatory variables, including age at surgery, gender, site of nerve injury, etiology of nerve injury, classification of nerve injury, duration from injury to repair, health comorbidities, and type of repair performed, were evaluated as potential factors in the outcomes. Wilcoxon signed rank analysis was used to compare demographic and injury characteristics of patients who had pain relief, partial pain relief, and no pain relief after surgery. Two-way analysis of variance and logistic regression analysis were used to evaluate the association between neuropathic pain and the explanatory variables. RESULTS: Twenty-eight patients met the inclusion criteria. Three cohorts of patients were identified and analyzed. The no-recurrence cohort included 7 patients who had neuropathic pain before surgery that was resolved with surgery. The complete-recurrence (CR) cohort included 10 patients who had neuropathic pain before surgery and complete recurrence of pain intensity after surgery. The incomplete-recurrence (ICR) cohort included 11 patients who had neuropathic pain before surgery and partial recurrence of pain intensity after surgery. There was no statistical difference in preoperative pain intensity levels among the 3 cohorts (P = .16), but there were statistical differences at 3 months (P = .007), 6 months (P < .0001), and 12 months (P < .0001). There were no statistical differences between the CR and ICR cohorts at 3 months (P = .502), 6 months (P = .1), and 12 months (P = .2). There was no effect by age, gender, injury type, Sunderland classification, injury etiology, duration from injury to repair, health comorbidity, or repair type on the outcome. CONCLUSIONS: The recurrence of neuropathic pain after trigeminal nerve repair for neuropathic pain is likely multifactorial and might not depend on factors that normally affect sensory recovery in patients who have no neuropathic pain (ie, age, duration of injury, type of injury, or repair type) and undergo trigeminal nerve surgery. These differences indicate that the understanding of trigeminal neuropathic pain is incomplete. Predictive outcomes of treatment will probably improve when the etiology is better defined to allow target- and site-specific treatment. In the meantime, trigeminal nerve surgery is a treatment option that offers a chance of decreasing or resolving pain intensity.

Sensory outcomes after reconstruction of lingual and inferior alveolar nerve discontinuities using processed nerve allograft--a case series.

PURPOSE: The present study describes the results of using a processed nerve allograft, Avance Nerve Graft, as an extracellular matrix scaffold for the reconstruction of lingual nerve (LN) and inferior alveolar nerve (IAN) discontinuities. PATIENTS AND METHODS: A retrospective analysis of the neurosensory outcomes for 26 subjects with 28 LN and IAN discontinuities reconstructed with a processed nerve allograft was conducted to determine the treatment effectiveness and safety. Sensory assessments were conducted preoperatively and 3, 6, and 12 months after surgical reconstruction. The outcomes population, those with at least 6 months of postoperative follow-up, included 21 subjects with 23 nerve defects. The neurosensory assessments included brush stroke directional sensation, static 2-point discrimination, contact detection, pressure pain threshold, and pressure pain tolerance. Using the clinical neurosensory testing scale, sensory impairment scores were assigned preoperatively and at each follow-up appointment. Improvement was defined as a score of normal, mild, or moderate. RESULTS: The neurosensory outcomes from LNs and IANs that had been microsurgically repaired with a processed nerve allograft were promising. Of those with nerve discontinuities treated, 87% had improved neurosensory scores with no reported adverse experiences. Similar levels of improvement, 87% for the LNs and 88% for the IANs, were achieved for both nerve types. Also, 100% sensory improvement was achieved in injuries repaired within 90 days of the injury compared with 77% sensory improvement in injuries repaired after 90 days. CONCLUSIONS: These results suggest that processed nerve allografts are an acceptable treatment option for reconstructing trigeminal nerve discontinuities. Additional studies will focus on reviewing the outcomes of additional cases.

The presence of neuropathic pain predicts postoperative neuropathic pain following trigeminal nerve repair.

PURPOSE: The risk for the continuation or recurrence of neuropathic pain following trigeminal nerve repair has never been examined. The objective of this study was to determine which risk factors might be associated with the continuation or recurrence of neuropathic pain following trigeminal nerve microneurosurgery. PATIENTS AND METHODS: An ambispective study design was used to assess subjects who underwent trigeminal nerve repair of the inferior alveolar nerve and lingual nerve between 2000 and 2010. The primary outcome was the presence or absence of neuropathic pain at 3, 6, and 12 months after surgery. Explanatory variables, including age at surgery, gender, presence of neuropathic pain before surgery, site of nerve injury, etiology of nerve injury, classification of nerve injury, duration of nerve injury, and type of repair performed, were abstracted from patient charts. Fisher exact tests were used to compare the demographic and injury characteristics of patients who presented with pain before surgery and those who did not. The McNemar test was used to assess whether there was a significant change in neuropathic pain report from before to after surgery. The level of significance was set at .50. RESULTS: Of the 65 patients analyzed, two-thirds were women; the average age was 36±16.1 years, and the median time between the injury and surgery was 6.4 months (interquartile range, 6.7 months). Lingual nerve injury type was the most frequent (62%). There was no statistically significant change in pain status from before to after surgery (P=.104). Only 1 patient had pain after surgery who had not had pain before surgery, while 67% of those with pain before surgery continued to have pain after surgery. Pain prior to surgery as a predictor of pain after had sensitivity of 91%, specificity of 88%, positive predictive value of 67%, and negative predictive value 97%. CONCLUSIONS: The presence of neuropathic pain prior to trigeminal microneurosurgery is the major risk factor for the continuation or recurrence of postoperative neuropathic pain. These findings suggest that trigeminal nerve surgery is not a risk factor for developing neuropathic pain in the absence of neuropathic pain before surgery.

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.

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.