Assessment of recovery from injury to inferior alveolar and mental nerves

Loop-Neurorrhaphy Technique for Preventing Bone Resorption and Preserving Sensation in Mandibular Reconstruction

BACKGROUND

The aim of this study was to investigate whether using an innervated vascularized iliac bone flap could effectively prevent bone resorption and maintain sensory function in the lower lip.

METHODS

In the innervated group, the deep circumflex iliac artery and recipient vessels were anastomosed, with simultaneous microanastomosis of ilioinguinal nerve, mental nerve, and inferior alveolar nerve. Conversely, the control group underwent solely vascular anastomosis. Computed tomography was used to assess bone quality. Sensory recovery of the lower lip was recorded using 2-point discrimination and current perception threshold testing.

RESULTS

The study comprised a total of 40 subjects, with each group accounting for 20 participants, equally distributed in terms of gender. Hounsfield unit loss was significantly lower in the innervated group (13.26% ± 8.65%) as compared with the control group (37.98% ± 8.60%) ( P < 0.001). Moreover, 2-point discrimination values were lower in the innervated group (15.11 ± 8.39 mm) when compared with the control group (21.44 ± 7.24 mm) ( P = 0.02). The current perception threshold values for the innervated group were 176.19 ± 31.89, 64.21 ± 19.23, and 42.29 ± 18.96 at 2 kHz, 250 Hz, and 5 Hz, respectively, whereas in the control group, the current perception threshold values were 204.47 ± 36.99, 82.26 ± 27.29, and 58.89 ± 25.38 at 2 kHz, 250 Hz, and 5 Hz ( P = 0.02, P = 0.02, and P = 0.03, respectively).

CONCLUSION

The innervated vascularized iliac bone flap represents a safe and effective novel approach to preserving lower lip sensation and preventing bone resorption through functional mandibular reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

Comparison of Neurosensory Recovery of the Inferior Alveolar Nerve After Open and Closed Reduction for Mandibular Fractures: A Prospective Study

INTRODUCTION

Traumatic mandibular fractures are the most common fractures of the facial region and are associated with loss of neurosensation in the inferior alveolar nerve (IAN). The present study aimed to compare IAN recovery after traumatic mandibular fractures between the open and closed reduction methods.

MATERIALS AND METHODS

The study included 90 patients with traumatic mandibular fractures of the body, angle, and symphysis, divided into two groups of 45 patients: group 1 was treated with closed reduction and fixation with rich arch-bar fixation under local anesthesia, and group 2 was treated with open reduction and rigid internal fixation with 2-mm titanium mini plates and monocortical screws (6 mm), and the plate was fixed to the fractured bony fragments. All patients underwent neurosensory testing using the Zuniga and Essick algorithm at baseline (preoperative), one week after surgery (postoperative), at three months, and at six months of follow-up.

RESULTS

No statistically significant differences were observed in IAN recovery between the groups. The most common site of fracture was the body (44% in group 1 and 56% in group 2). The maximum recovery was observed in the younger age group (25-30 years). At baseline, functional nerve recovery was observed in 40 cases (88%) in group 1 and 38 cases (84%) in group 2, and the difference was not statistically significant. Levels A and B tests were affected by surgical management and improved after three months. The total recovery in group 1 ranged from 60% to 80%, and that in group 2 ranged from 56% to 72%.

CONCLUSION

Based on the findings of the current study, both methods are recommended for surgical management of traumatic mandibular fractures with IAN recovery in 60-80% of cases six months postoperatively.

Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence Patients

ABSTRACT

There has yet to be a consensus on the appropriate technique for mandibular distraction in the infant Pierre Robin population nor is their sufficient data on sensory nerve outcomes. The purpose of this study is to validate the safety of the horizontal osteotomy by: (1) determining mandibular foramen location in infant Pierre Robin patients relative to the dentoalveolar plane and (2) evaluate long-term function of the inferior alveolar nerve in previously distracted Pierre Robin patients. Preoperative 3D Computed tomography (CT) scans of Pierre Robin patients < 1 year old were reviewed. A line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen was then measured. Semmes-Weinstein monofilaments of the lower lip and chin bilaterally was performed on mandibular distraction patients in clinic. Inclusion criteria was patients >6 years of age having undergone bilateral mandibular distraction at <1 year of age. Fifteen patients' CT studies were examined. The mandibular foramen was consistently below the level of the dentoalveolar plane at an average distance of 4.7 mm. Eight patients were included in the prospective arm. Average age was 12.2. All patients had normal sensation at 2.83 through all areas. The mandibular foramen reliably exists below the dentoalveolar plane. In addition, all patients reviewed postoperatively with >10 years of follow up demonstrated normative sensation. The horizontal corticotomy performed just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in young Pierre Robin patients undergoing distraction.

The Assessment of Neurosensory Disturbance Following Bilateral Sagittal Split Osteotomy With Subjective and Three-Dimensional Evaluation

PURPOSE

Inferior alveolar neurosensory disturbance (IAND) is the most common complication of bilateral sagittal split osteotomy (BSSO). The aim of the present study was to evaluate IAND with subjective tests postoperatively and assess the relationship between three-dimensional measurements of the mandibular canal (MC) and IAND.

METHODS

Eighteen patients (Mean age: 24.05 ± 5.85 years) treated with BSSO were retrieved from the archive. Subjective tests (light touch, tactile sensitivity, 2-point discrimination, brush-stroke directional discrimination, sharp/blunt discrimination, dental vitality, questionnaire) and three-dimensional measurements related to MC and fixation screws were done postoperatively (on average 20.43 ± 8.76 months after surgery). Statistical significance was set at P < 0.05.

RESULTS

Subjective test results were found compatible with each other except brush-stroke directional discrimination test. According to the questionnaire, IAND was apparent in all patients immediately after surgery, and recovery after 1 to 2 years was statistically significant (P < 0.05). Preoperative ramus width, medial and lateral cancellous bone lengths, the decrease in MC length, and the presence of screw in MC were not related to IAND (P < 0.05).

CONCLUSIONS

There is a high incidence of IAND following BSSO, and the subjective tests are efficient to evaluate the disturbance. Spontaneous recovery of the nerve occurs during the follow-up periods. Instead of preoperative measurements of bone thickness, MC length, and the position of fixation screws, the surgical procedure seems to be more important in IAND occurrence.

Inferior alveolar nerve dysfunction in mandibular fractures: a prospective cohort study

Objectives

To assess the prevalence and recovery of inferior alveolar nerve dysfunction (IAND) in mandibular fractures.

Materials and Methods

This was a prospective cohort study. Clinical neurosensory testing was done preoperatively and the IAND was categorized as mild, moderate or severe. Postoperatively, neurosensory testing was repeated at 1 day, 1 week, 1 month, 3 months and every 3 months thereafter.

Results

A total of 257 patients with 420 fractures were included in the study with a mean age of 31.7 years. Body fractures (95.9%) had the highest incidence of IAND, followed by the angle fractures (90.1%) and symphysis fractures (27.6%). The condyle and coronoid fractures did not have any IAND and hence were excluded from further study. After eliminating those cases, 232 patients remained in the study with 293 fractures. The overall prevalence of IAND in fractures occurring distal to the mandibular foramen was 56.3%. The changes until 1 week were minimal. From 1 month to 6 months, there was a significant reduction in the severity of IAND. A significant number of cases (60.0%) were lost to follow-up between 6 and 9 months. At 6 months, 23.9% of cases still had some form of IAND and 95.0% of the symphysis, 59.0% of the angle and 34.8% of the body fractures with IAND had become normal.

Conclusion

This study documents the reduction in the degree of severity of IAND in the first six months and provides the basis for future studies with longer periods of follow-up.

Relationship Between the Quantity of Nerve Exposure During Bilateral Sagittal Split Osteotomy Surgery and Sensitive Recovery

AIM AND OBJECTIVES

The purpose of this study was to evaluate how different exposures of the V3 nerves during orthognathic surgery impact neurosensory disturbances.

METHODS

The study included 127 patients who underwent either bilateral sagittal split osteotomy (BSSO) or BSSO with maxillary le Fort 1. They were divided into 6 groups, identified by the quantity of V3 nerve exposure. All patients were examined in a pre-op period and again after 1, 3, 6 months post-op. The standardized tests used were to clarify the objective and subjective neurosensory status of the exposed nerve. Neurosensory evaluation included; a pin prick test, the 2 points discriminator, light touch, warm and cold tests, and blunt discrimination. They were all done bilaterally on the lower lip area.

RESULTS

In only 2 patients the nerve was damaged during surgery and thus they were not included in this study. In 10.2% of patients there was no nerve exposure, 25.2% had longitudinal vestibular segment nerve exposed, 22.8% had the longitudinal upper-vestibular segment exposed, 20.5% had the longitudinal lower-vestibular segment exposed, 14.2% had the longitudinal upper-lower-vestibular segment exposed, and in 7.1% of patients the nerve was totally exposed. Given the estimated time of 1 month there was 100% recovery in patients whose nerve was unexposed. Considering the other patients, the authors had a variable number of patients who did not recover completely.

CONCLUSION

The authors estimate a correlation between the recovery time and the quantity of the exposed nerve. There is a high incidence of neurosensory disturbance in the lower lip and chin after BSSO and intraoperative quantity of nerve exposure.

Identifying criteria for diagnosis of post-traumatic pain and altered sensation of the maxillary and mandibular branches of the trigeminal nerve: a systematic review

OBJECTIVE

The aim of the study was to systematically identify criteria used to diagnose patients with trigeminal nerve injury.

STUDY DESIGN

A systematic review of the literature registered in the PROSPERO database. Inclusion criteria were patients diagnosed with nerve injury of the sensory divisions of the maxillary or mandibular branches of the trigeminal nerve, with reported tests and criteria used for diagnosis and persistent pain or unpleasant sensation associated with nerve injury.

RESULTS

In total, 28 articles were included. Diagnostic tests included clinical neurosensory tests (89%), thermal quantitative sensory testing (QST; 25%), electromyography (7%), and patient interview (14%). Neuropathic pain was assessed by using the visual analogue scale (39%); patient use of neuropathic medication (7%); questionnaires, including McGill and PainDETECT (21%). Functional impact was assessed in 14% and psychological impact in 7% of articles. Methodology in performing clinical neurosensory tests, application of diagnostic terms and diagnostic grading of nerve injury was found to be inconsistent among the included articles, making direct comparison of results difficult.

CONCLUSIONS

Recommendations for assessment and diagnosis of trigeminal nerve injury have been made based on the best available evidence from the review. There is an urgent requirement for a consensus in diagnostic criteria, criteria for assessment, and outcome reporting among stakeholder organizations to improve knowledge in this field.

Inferior Alveolar Nerve Mobilization Using Ultrasonic Surgery With Crestal Approach Technique, Followed by Immediate Implant Insertion: Evaluation of Neurosensory Disturbance

Many techniques are described for atrophied mandibles rehabilitation. This article reports on 12 clinical patients of severely atrophied posterior mandibles. In all the patients, a cone beam is performed before the crestal surgical approach to inferior alveolar nerve (IAN) mobilization. For the realization of this technique the piezosurgery device was used to minimize IAN injuries. With the help of this device the selective cutting of the bone has been possible until IAN exposure, in the implant placement site. At the same time, the authors performed the implant osteotomy and implant placement. After 4 months of healing, all implants were osseointegrated and the implant-supported bridges were done.Evaluation by means of neurosurgery function test over a 36-months period found that all patients had a return to normal sensation, after a brief period of neurosensory disturbance.

Piezosurgery for Sagittal Split Osteotomy: Procedure Duration and Postoperative Sensory Perturbation

PURPOSE

To evaluate piezosurgery for bilateral sagittal split osteotomy (BSSO) for its duration and inferior alveolar nerve (IAN) perturbation.

PATIENTS AND METHODS

In this prospective randomized study, the authors evaluated 100 BSSO procedures in 50 patients. Piezoelectric (group I) and conventional (group II) osteotomies were carried out on each side of the mandible of a patient by 2 specialists. The surgeons had at least 1 year of experience using piezosurgery. The period from incision to complete splitting of the mandibular bone was recorded (ie, procedure duration). The intraoperative status (visibility and relocation) of the IAN also was recorded. The neurosensory function of the IAN was measured by the 2-point discrimination threshold and static light touch methods before surgery and postoperatively (1, 3, and 6 weeks and 6 and 12 months). Parameters were compared between the test groups by the paired t, nonparametric Wilcoxon, or χ² test.

RESULTS

Intergroup comparison showed the mean duration of osteotomy was significantly shorter for group I (17 ± 6 vs 25 ± 9 minutes; P < .001). The rate of intraoperative exposures of the IAN was slightly lower for group I (68%) compared with group II (81%). However, the difference was not relevant. Neurosensory disturbance and recovery of the IAN did not differ between groups.

CONCLUSION

Piezoelectric osteotomy requires considerably less time than conventional mechanical approaches, but shows no advantage in preventing neurosensory perturbation.

J-Graft for Correction of Vertical and Horizontal Maxillary Bone Defects

INTRODUCTION

This prospective study aims to evaluate the reliability of a reconstructive technique, which uses autologous J-shaped graft (J-graft) harvested from the mandibular ramus.

MATERIALS AND METHODS

Thirty-six maxillary defects among 32 patients (20 women and 12 men) were treated. All patients presented enough bone volume at the donor site to perform the harvesting procedures needed for the autologous reconstruction. All patients underwent clinical and radiographical evaluations through standardized radiographs taken before the intervention, immediately after the bone grafting, 6 to 7 months, and 1 year later. The loss of tooth vitality, the alterations of skin and mucosa sensibility, and the patients' subjective perception of discomfort related to the surgical procedure were investigated.

RESULTS

We found an overall success rate of 91.66% with a mean bone gain of 4.8 mm vertically and 5.6 mm horizontally, assessed through computed tomography. According to clinical examinations, 35 sites completely recovered with proper incorporation of the graft, whereas 33 sites reached enough bone volume to allow the implant placement.

CONCLUSION

The described technique explains how to harvest and shape a J-graft. It achieves the simultaneous restoration of the horizontal and vertical bone loss with a single bone block.

Post-traumatic and postoperative neurosensory deficits of the inferior alveolar nerve in mandibular fracture: a prospective study

Objectives

We evaluated and recorded post-traumatic and postoperative neurosensory deficits of the inferior alveolar nerve (IAN) in mandibular fracture in order to identify associated risk factors.

Materials and Methods

This was a prospective cohort study composed of 60 patients treated for mandibular fracture. The primary study variable was the change between the post-traumatic IAN neurosensory examination score and the score after fracture reduction. Risk factors were categorized as demographic, anatomic, fracture displacement, and treatment. Appropriate descriptive and bivariate statistics were computed.

Results

Sixty patients with unilateral mandibular fracture reported within 24 hours of injury were evaluated over a one-year period. A post-traumatic neurosensory deficit was observed in 52 patients (86.7%), the percentage of which was reduced to 23.3% over the follow-up period. Abnormal postoperative neurosensory scores were significantly higher in angle fracture cases (33.3%) compared to body fracture cases (11.1%). When recovered and non-recovered neurosensory scores were compared by fracture location, 88.9% of body fracture cases showed significant recovery compared to 66.7% of mandibular angle fracture cases. Cases with less than 5 mm fracture displacement showed statistically significantly higher neurosensory recovery scores (90.6%) compared to those with more than 5 mm fracture displacement (60.7%).

Conclusion

Use of a miniplate with mono-cortical screws does not play a role in increasing IAN post-traumatic neurosensory deficit. Early management can reduce the chances of permanent neurosensory deficit. Mandibular fracture displacement of 5 mm or more and fracture location were found to be associated with an increased risk of post-traumatic IAN neurosensory score worsening.

Schwann-like cells differentiated from human dental pulp stem cells combined with a pulsed electromagnetic field can improve peripheral nerve regeneration

The purpose of this study was to investigate the effect of Schwann-like cells combined with pulsed electromagnetic field (PEMF) on peripheral nerve regeneration. Schwann-like cells were derived from human dental pulp stem cells (hDPSCs) and verified with CD104, S100, glial fibrillary acidic protein (GFAP), laminin, and P75^NTR immunocytochemistry. Gene expression of P75^NTR and S100 were analyzed. Male Sprague-Dawley rats (200-250g, 6-week-old) were divided into seven groups (n = 10 each): control, sham, PEMF, hDPSCs, hDPSCs + PEMF, Schwann-like cells, Schwann-like cells + PEMF. Cells were transplanted (1 × 10⁶ /10µl/rat) at crush-injury site or combined with PEMF (50 Hz, 1 h/day, 1 mT). Nerve regeneration was evaluated with functional test, histomorphometry and retrograde labelled neurons. Schwann-like cells expressed CD104, S100, GFAP, laminin, and p75 neurotrophin receptor (P75^NTR ). P75^NTR and S100 mRNA expression was highest in Schwann-like cells + PEMF group, which also showed increased Difference and Gap scores. Axons and retrograde labeled neurons increased in all treatment groups. Schwann-like cells, hDPSCs with or without PEMF, and PEMF only improved peripheral nerve regeneration. Schwann-like cells + PEMF showed highest regeneration ability; PEMF has additive effect on hDPSCs, Schwann-like cell in vitro and nerve regeneration ability after transplantation in vivo. Bioelectromagnetics. 37:163-174, 2016. © 2016 Wiley Periodicals, Inc.

Nerve injury associated with orthognathic surgery. Part 2: inferior alveolar nerve

The inferior alveolar nerve (IAN) is the most commonly injured structure during mandibular osteotomies. The prevalence of temporary injury has been reported as 70/100 patients (95% CI 67 to 73/100) or 56/100 nerves (95% CI 46 to 65/100), and the prevalence of permanent alteration in sensation was 33/100 patients (95% CI 30 to 35/100) or 20/100 nerves (95% CI 18 to 21/100) when assessed subjectively. The prevalence varied significantly between different operations (p<0.0001). It was significantly higher for sagittal split osteotomy (SSO) combined with genioplasty than for SSO alone (p<0.0001) or vertical ramus osteotomy (VRO) (p<0.0001). Injury may result from traction during stripping or manipulation of the distal fragment, incorrect placement of the cuts, or misjudged placement of fixation in ramus ostotomy. During SSO, they can occur during retraction to make cuts in the medial ramus, when the bone is cut or split, and on fixation. The impact of injury is generally said to be low as it does not seem to affect patients' opinions about the operation.

Evaluation of neurosensory disturbance following orthognathic surgery: a prospective study

AIM AND OBJECTIVES

The prospective study was to evaluate the incidence, type of neurosensory disturbance (NSD), grade its severity and monitor its recovery occurring in the lower lip and chin due to damage to inferior alveolar nerve following orthognathic surgery involving mandible.

MATERIALS AND METHODS

The study included 10 patients who have undergone sagittal split osteotomy, genioplasty, and anterior subapical osteotomy (ASO). All the patients examined preoperatively and post operatively 1 week, 1 and 6 months according to standardized test to clarify the subjective and objective neurosensory status of the injured nerve. Pin prick test, blunt test, two-point discrimator test, brush stoke direction, light touch test, warm and cold test were used bilaterally to lower lip and chin area.

RESULTS

Seven patients underwent bilateral sagittal split osteotomy (BSSO) (70 %), one patient had BSSO with genioplasty (10 %), two patients had BSSO with ASO (20 %). During the operation none of the nerves were transectioned, in 60 % of patients nerve was not visible and in 40 % of patients nerve was seen in distal segment. 70 % of patients underwent setback, 30 % of patients underwent advancement. The subjective evaluation of the patients revealed the incidence of 90 % at 1 week, 30 % at 1 month, 20 % at 6 months and 10 % at 1 year post operatively. The altered sensation reported subjectively was hypoesthesia in 50 % of the patients, anaesthesia in 40 % of the patients. There was 100 % recovery in advancement cases and 93.5 % recovery in setback cases.

CONCLUSION

There is a high incidence of NSD of the lower lip and chin after BSSO related to advancement, setback, intraoperative nerve encounter and surgical skill. However, recovery of sensation occurs with increasing frequency during the follow-up period. The clinical neurosensory tests are effective guides to study the neurosensory deficit.

Inferior alveolar nerve injuries associated with mandibular fractures

The study evaluates the incidence of inferior alveolar nerve injuries in mandibular fractures, the duration of their recovery, and the factors associated with them. Fifty-two patients with mandibular fractures involving the ramus, angle, and body regions were included in this study; the inferior alveolar nerve was examined for neurological deficit posttraumatically using sharp/blunt differentiation method, and during the follow-up period the progression of neural recovery was assessed. The incidence of neural injury of the inferior alveolar nerve was 42.3%, comminuted and displaced linear fractures were associated with higher incidence of inferior alveolar nerve injury and prolonged recovery time, and recovery of inferior alveolar nerve function occurred in 91%.Fractures of the mandible involving the ramus, angle, and body regions, and comminuted and displaced linear fractures are factors that increase the incidence of inferior alveolar nerve injuries. Missile injuries can be considered as another risk factor.

Sensibility and taste alterations after impacted lower third molar extractions. A prospective cohort study

Objectives: To determine the incidence, severity and duration of lingual tactile and gustatory function impairments after lower third molar removal. Study Design: Prospective cohort study with intra-subject measures of 16 patients undergoing lower third molar extractions. Sensibility and gustatory functions were evaluated in each subject preoperatively, one week and one month after the extraction, using Semmes-Weinstein monofilaments and 5 different concentrations of NaCl, respectively. Additionally, all patients filled a questionnaire to assess subjective perceptions. Results: Although patients did not perceive any sensibility impairments, a statistically significant decrease was detected when Semmes-Weinstein monofilaments. This alteration was present at one week after the surgical procedure and fully recovered one month after the extraction. There were no variations regarding the gustatory function. Conclusions: Lower third molar removal under local anesthesia may cause light lingual sensibility impairment. Most of these alterations remain undetected to patients. These lingual nerve injuries are present one week after the extraction and recover one month after surgery. The taste seems to remain unaffected after these procedures.

Key words:Lingual nerve, third molar, nerve injury, paresthesia, surgical extraction

Mandibular bone harvesting for alveolar reconstruction and implant placement: subjective and objective cross-sectional evaluation of donor and recipient site up to 4 years

AIM

To evaluate the long-term morbidity of intraoral bone harvesting from two different donor sites (mandibular symphysis or ramus) for bone augmentation procedures before or at the time of implant placement and to evaluate the success and the survival rates of implants placed in sites augmented with mandibular bone.

METHODS

Seventy-eight patients who received mandibular bone grafts were recalled after 18-42 months follow-up (mean 29 months). The group consisted of 36 men and 42 women aged between 18 and 68 years old at the moment of augmentation surgery. Vitality of teeth adjacent to the harvesting sites was investigated. Soft tissue superficial sensory function was assessed by the Pointed-Blunt Test and the Two-Point-Discrimination Test. Implant health status was assessed measuring peri-implant probing depth and bleeding on probing. Implant survival and success rates were also calculated. In order to evaluate patients' perception of the morbidity of the procedures, the patients were asked to answer several questions by means of visual analogue scales (VAS).

RESULTS

Only two teeth (out of 282) in the chin harvesting group needed root canal treatment after surgery. A higher frequency of minor temporary and permanent sensorial disturbances was found in the group of patients who received chin harvesting procedures (2.3% vs. 13%P=0.03), while pain during chewing and bleeding were more frequently recorded after ramus harvesting (9.8% vs. 0%P=0.03). No permanent anesthesia of any region of the skin was reported. Implants' survival and success rate were comparable to implants placed in bone reconstructed with other techniques and were not influenced by the choice of the donor site. Patient's perception regarding the morbidity of the procedures was very low and did not differ between ramus and chin harvesting groups (mean VAS scores <4).

CONCLUSION

The present cross-sectional retrospective study demonstrated the safety of mandibular grafts that reported excellent results in terms of implant success and survival rates with minor complications regarding the donor site area. When the chin was chosen as donor site, minor sensorial disturbances of mucosa and teeth were recorded. The majority of these disturbances were temporary; only few of them were permanent but still had no impact on patient's life.

Inferior alveolar nerve injury following orthognathic surgery: a review of assessment issues

The sensory branches of the trigeminal nerve encode information about facial expressions, speaking and chewing movements, and stimuli that come into contact with the orofacial tissues. Whatever the cause, damage to the inferior alveolar nerve negatively affects the quality of facial sensibility as well as the patient's ability to translate patterns of altered nerve activity into functionally meaningful motor behaviours. There is no generally accepted, standard method of estimating sensory disturbances in the distribution of the inferior alveolar nerve following injury. Assessment of sensory alterations can be conducted using three types of measures: (i) objective electrophysiological measures of nerve conduction, (ii) sensory testing (stimulus) measures and (iii) patient report. Each type of measure with advantages and disadvantages for use are reviewed.

Five-year retrospective study of mandibular fractures in Freiburg, Germany: incidence, etiology, treatment, and complications

PURPOSE

To evaluate current trends in maxillofacial trauma, a retrospective review of mandibular fractures at a German university hospital was carried out.

PATIENTS AND METHODS

In this retrospective study, records of 444 patients with mandibular fractures between 2000 and 2005 at the Department of Oral and Maxillofacial Surgery, University Hospital of Freiburg, Germany, were reviewed. A total of 444 patients presented with 696 mandibular fractures.

RESULTS

Three hundred twenty-nine (74%) of the fractures occurred in male and 115 (26%) in female patients (2.9:1). One hundred forty-two fractures (32%) resulted from road traffic accidents, 126 from fights (28%), and 116 from falls (26%). Forty-four fractures were caused by sport accidents (10%) and 16 by pathologic fractures (4%). The mandibular condyle area was the most common fracture site, with 291 fractures (42%), followed by 144 fractures of the symphyseal and parasymphyseal area (21%) and 141 angle fractures (20%). Combined fractures were found in nearly half of the cases. Five hundred seventy-nine (83%) of patients with mandibular fractures were treated by surgical intervention, 117 (17%) of patients conservatively. Regarding the surgical treatment, 561 (65%) miniplates, 247 (29%) locking plates, and 51 (6%) lag screws were used. Complications, such as postoperative infections, abscesses, and osteomyelitis appeared in 66 (9%) cases.

CONCLUSION

We concluded that osteosynthesis of mandibular fractures by miniplates and locking plates are both reliable.

Superior Border Plating Technique in the Management of Isolated Mandibular Angle Fractures: A Retrospective Study of 50 Consecutive Patients

PURPOSE

To determine the complication rate for patients presenting with isolated mandibular angle fractures treated by open reduction and internal fixation using a single superior border miniplate technique.

PATIENTS AND METHODS

This is a retrospective study of consecutive patients with isolated mandibular angle fractures treated using a specific protocol at a Regional Oral and Maxillofacial Department between January 1998 and December 2004. Patient demographics, fracture etiology, length of hospital stay, removal of third molar, and postoperative complications were recorded. Preoperative and postoperative inferior alveolar nerve function was recorded. Objective sensory testing and patient interviews were conducted to determine the incidence of postoperative sensory deficit.

RESULTS

The study population included 50 patients presenting with isolated mandibular angle fractures, 6 patients (12%) experienced complications requiring bone plate removal. These complications were minor and occurred after fracture healing as follows: 4 patients (8%) experienced superficial soft tissue infection associated with the bone plate, treated with oral antibiotics, 1 patient (2%) experienced bone plate exposure, and a further patient (2%) presented with a fractured bone plate. All 6 patients (12%) were treated by bone plate removal under general anesthesia as elective day case surgery. Thirty-nine (78%) patients had long-term sensory follow-up, mean 37 months (2 to 84 months). Permanent inferior alveolar sensory deficit (>12 months) was present in 4 (8%). Five of 26 (19%) patients with normal postinjury/preoperative sensory function had a postoperative sensory deficit. All patients in this group reported recovery of normal sensation within 6 months.

CONCLUSIONS

The results of this study suggest that the complication rates associated with the treatment of isolated mandibular angle fractures using a superior border plating technique, in this patient population, is relatively low (12%). The complications were all minor in nature. There was a permanent (>12 months) inferior alveolar sensory deficit in 4 (8%) patients.

Mandibular Osteotomies in Orthognathic Surgery

Bilateral sagittal split osteotomy is the most commonly used osteotomy of the mandible in orthognathic surgery. The authors describe their experience in evaluating the orthognathic patient with a mandibular deformity. The bilateral sagittal split osteotomy surgical technique used by the authors is reviewed along with postoperative management.

Thermographic assessment of inferior alveolar nerve injury in patients with dentofacial deformity

PURPOSE

The purpose of this study was to evaluate the injury and recovery of the inferior alveolar nerve in orthognathic patients at 1 and 4 weeks after surgery using electronic thermography.

MATERIALS AND METHODS

Twenty subjects with Class III dentofacial deformity were studied. All patients underwent bilateral sagittal split ramus osteotomy. To image the temperature of the face, 1 anteroposterior view and 1 lateral view were taken from both the right and left sides. Similar images were taken at 1 and 4 weeks after surgery. The control was the presurgical temperature of the 20 patients who showed unilateral or bilateral nerve damage after surgery.

RESULTS

In the patients with unilateral nerve damage (n = 14), on the anteroposterior views, the temperatures of the mentum on the 2 sides differed by 0.64 degrees C at 1 week after surgery, and the difference decreased to 0.23 degrees C at 4 weeks after surgery. On the lateral images, the differences in temperature between the mentum areas were 0.10 degrees C at 1 week and 0.27 degrees C at 4 weeks after surgery. In the patients with bilateral nerve injury (n = 6), on the anteroposterior views, the temperatures of the mentum on the 2 sides differed by 0.20 degrees C at 1 week after surgery and 0.13 degrees C after 4 weeks. On the lateral views, the differences were 0.18 degrees C at 1 week and 0.34 degrees C at 4 weeks after surgery. Using the repeated measurement analysis method, the anteroposterior view showed statistically significant results in the patients with unilateral nerve damage.

CONCLUSION

The infrared body temperature method is an objective method that can be applied as a supplemental diagnostic method for inferior alveolar nerve injury.

[Quantitative determination of thermosensitivity after mandibular sagittal split osteotomy]

BACKGROUND

To determine the temperature- and pain thresholds of patients (n=20) who had undergone mandibular sagittal split osteotomy (MSSO), we developed a specific thermal probe to evaluate the neurosensory disturbances of the inferior alveolar nerve under prospective study conditions.

METHODS

Measurements were performed prior to surgery and postoperatively up to 6 months. Thermal probe test results were compared to the results of the usual two-point discrimination test and the sharp/blunt test. Furthermore we took the subjective neurosensory perception of each patient into account.

RESULTS

With focus on our newly developed thermal probe and under comparison with the preoperative results, the postoperative neurosensory tests revealed increased thresholds of up to 12.7 degrees C. Between 3 and 6 months postoperatively, quantitative resensitization could be evaluated. In contrast, the usual testing methods were not accurate enough to give valuable significant data within 3 and 6 months postoperatively. Our evaluation could also show that after 6 months thermal thresholds were up 1.5 degrees C as compared with the preoperative status.

CONCLUSION

Base on our data we conclude that the newly developed thermal probe is accurate to determine neurosensory disturbances of the alveolar inferior nerve after sagittal split osteotomy. As compared with the more common testing methods, an advantage of our contemporary measurement device is the quantitative analysis of nerval function.

Simplifying the assessment of the recovery from surgical injury to the lingual nerve

OBJECTIVE

To determine the sensitivity of conventional sensory assessment in monitoring lingual nerve recovery subsequent to third molar surgery and to evaluate if the assessment methods can be predictive of injury outcome.

METHOD

A prospective case series of 94 patients presenting with lingual nerve injuries evaluated using objective mechanosensory and subjective methods during the recovery period of up to 12 months.

RESULTS

The conventional tests were often unable to diagnose the presence of injury due to variability and they were not predictive of outcome. As a result of this study, we are able to identify patients more likely to have permanent rather than temporary lingual nerve injury at four to eight weeks post injury, using patient reported subjective function. The subjective function test also minimises the requirements for specialist training or equipment providing an ideal method for general dental practice.

CONCLUSIONS

The development of these simple subjective tests may enable us to identify which patients are at risk of permanent lingual nerve injuries in the early post injury phase, thus allowing expeditious therapy when indicated.

Characterization of different paresthesias following orthognathic surgery of the mandible

PURPOSE

Paresthesia is a well known consequence of peripheral nerve injury. However, the neural mechanisms of the 2 recognized types, spontaneous and elicited, are currently unknown. This study aimed to investigate these 2 paresthesias and the possible mechanisms accompanying orthognathic surgery.

PATIENTS AND METHODS

Mechanical-touch thresholds and current perception threshold were measured before and 7 days after surgery in 60 chin sites (mental nerve area) of 30 patients who underwent orthognathic surgery. Similar testing was conducted on healthy volunteers (controls). All sites were classified by the presence or absence of each paresthesia: spontaneous paresthesia or no spontaneous paresthesia, and elicited paresthesia or no elicited paresthesia. Presence or absence analyses were followed-up for 6 weeks after surgery.

RESULTS

Gender differences and maxillary surgery did not change the incidence of paresthesia during postoperative week 1 (chi-square test, P > .05). A significantly higher mechanical-touch threshold was observed with spontaneous paresthesia compared with no spontaneous paresthesia (Mann-Whitney U-test; P < .05), but not between no elicited paresthesia and elicited paresthesia (Mann-Whitney U-test; P > .05). A significant increase in postsurgery current perception thresholds values compared with presurgery values was observed at 2,000 Hz in spontaneous paresthesia, and at 2,000 and 5 Hz in elicited paresthesia (paired t test, P < .05). The incidence of spontaneous paresthesia decreased more rapidly than elicited, while the latter tended to increase again during the 6-week postsurgical test period.

CONCLUSION

The results suggested that both spontaneous and elicited paresthesias are associated with damage and dysfunction in myelinated primary afferent fibers, but additional neural mechanisms are implicated during elicited paresthesia.

Perioperative neurosensory changes associated with treatment of mandibular fractures

PURPOSE

The purpose of this study was to document perioperative neurosensory changes in the inferior alveolar nerve (IAN) after mandibular fracture treatment and to identify risk factors associated with these changes.

MATERIALS AND METHODS

This was a prospective cohort study composed of patients treated for mandibular fractures. The primary study variable was the change between the postinjury/pretreatment IAN neurosensory examination score and the score after fracture reduction. Risk factors were categorized as demographic, anatomic, and treatment. Appropriate descriptive, bivariate, and multivariate statistics were computed.

RESULTS

The cohort was composed of 61 patients with 97 fractured sides. Forty-seven fractures (49%) were located between the lingula and mental foramen, and 50 fractures (51%) were located distal to the mental foramen. Thirty-nine fractures (41%) were displaced by 5 mm or more. Abnormal preoperative IAN neurosensory examinations were documented in 81% of the fractured sides. Fifty-three fractures (54%) were treated by closed reduction and 44 (46%) by open reduction and internal fixation. In 82 fractures (85%), the IAN neurosensory score was unchanged or improved after treatment. In a multivariate model, preoperative neurosensory score, displacement, and treatment were associated with a statistically significant risk (P < or =.05) for postoperative deterioration of IAN sensation.

CONCLUSION

Open reduction and internal fixation, fracture displacement of 5 mm or more, and a normal preoperative IAN neurosensory examination were associated with an increased risk for deterioration of the IAN neurosensory score after treatment of mandibular fractures. Additional studies are indicated to determine long-term IAN neurosensory function after mandibular fracture treatment and the factors that affect prognosis.

An evaluation of clinical and electrophysiologic tests in nerve injury diagnosis after mandibular sagittal split osteotomy

The yield of clinical sensory tests and electrophysiologic tests in the diagnostics of inferior alveolar nerve (IAN) damage after bilateral sagittal split osteotomy (BSSO) was studied. The diagnostic value of these tests was evaluated by comparing the test results to the degree of nerve damage at the end of the operation as documented by means of the intraoperative nerve conduction recording of the IAN. Twenty patients undergoing BSSO were analysed preoperatively and 2 weeks postoperatively. The frequency of the IAN disturbance ranged from 10% to 94% depending on the test method and the test site used. Of the clinical sensory tests, the touch detection threshold (TD) test was the most sensitive and clinically useful test. It also correlated best with the electrophysiologically verified intraoperative nerve damage (R = -0.603, P = 0.017 on the right, R = -0.626, P = 0.01 on the left). The blink reflex and quantitative cold detection threshold tests were almost as often abnormal as the TD-test, but nerve conduction study (NCS) was the most sensitive (88%) of all clinical and electrophysiologic tests. The frequency of abnormal findings in the electrophysiologic tests indicating IAN injury, 75% on the right side and 90% on the left side, corresponded exactly with the figures of subjective sensory alteration. Almost all electrophysiologic tests showed obvious associations with the objectively verified IAN damage. All tests, except the NCS, showed only moderate sensitivity. Specificity of the tests was generally high, the only exceptions being the TD test and the NCS. To increase the diagnostic accuracy of the testing and to detect different types of damage in different nerve fibre populations, a combination of different sensory and electrophysiologic tests is recommended.

Mechanosensory and thermosensory changes across the border of impaired sensitivity to pinprick after mandibular nerve injury

PURPOSE

The study goal was to determine how sensory function varies across the border of impaired sensitivity to pinprick in patients with mandibular nerve injuries.

PATIENTS AND METHODS

Borders of decreased sensitivity to pinprick were mapped in 15 patients who reported altered sensation. Four mechanoreceptive, 2 thermoreceptive, and 2 thermonociceptive functions were studied at 5 sites separated by 0.6 cm across the border. The tests were repeated to evaluate day-to-day consistency in the pattern of variation for each sensory measure.

RESULTS

The estimates of sensory function were not found to vary in a systematic manner from outside to inside the pinprick-impaired area for all patients for any of the 8 tests. However, for every test, some patients exhibited large variations. On average, the magnitudes of loss in contact detection, subjective intensity of light touch, and direction discrimination were greatest; the magnitudes of loss in 2-point perception and in heat and cold pain perception were least. Some patients provided no evidence of impairment on certain tests. For some patients, the estimates suggested increased sensitivity within the pinprick-impaired area (eg, to noxious cold stimuli).

CONCLUSIONS

Although certain patients exhibit impairment, there is no obligatory loss in light touch, 2-point perception, direction discrimination, or temperature perception across the border of decreased sensitivity to pinprick. The differences among patients suggest that the data from individual patients should be evaluated in clinical studies and in clinical practice. Researchers should not rely solely on average values and summary statistics.

Morbidity of harvesting of chin grafts: a prospective study

In a prospective study, 20 patients who underwent harvesting of chin grafts as outpatients, were followed up for 12 months (3 further patients with incomplete follow-up data were excluded from the study). Preoperatively and 7 days, 1, 3, 6 and 12 months postoperatively, follow-up data were assessed. Evaluation of the superficial sensory function of the inferior alveolar nerve was determined by the Pointed-Blunt Test and the Two-Point-Discrimination Test. Sensory disturbances were objectively assessed by testing thermal sensitivity with the "Pain and Thermal Sensitivity" Test (PATH Test). In addition, evaluation of the pulp sensitivity of teeth 35-45 was carried out by cold vitality testing. One week postoperatively, 8 patients were affected by superficial sensory impairment. 8 nerve territories showed hypoaesthetic reactions and 5 showed hyperaesthetic reactions. After 12 months, two patients still suffered from hypoaesthesia of one side of the chin. There was a statistically significant sensitivity impairment of the chin for all patients comparing the preoperative data of the Two-Point-Discrimination Test (left/right median: 8.17/8.17 mm, interquartile range (IQR) 1.00/2.00 mm) with the first postoperative measurement (left/right median 9.00/8.33 mm, IQR 1.67/2.66 mm). Comparing the latter to the last postoperative measurement there was significant tendency for regeneration of a nerve function (left/right median 8.00/7.84 mm, IQR 0.66/2.00 mm). In the PATH Test all hypoaesthetic areas could be identified by a reduction of thermal sensitivity. After the first postoperative examination 21.6% (n=38/176) of the examined teeth had lost their pulp sensitivity. After 12 postoperative months 11.4% (n=20/176) still did not react sensitively. Many of these were canines (n=8/20). Comparing the preoperative to the first postoperative examination, there was a significant reduction of pulp sensitivity. However, statistically significant recovery until the last postoperative follow-up could not be detected. The assessed data show that patients have to be informed extensively about disturbances of the inferior alveolar nerve function lasting longer than 12 months. Moreover, the loss of pulp sensitivity is a very frequent event which has always to be taken into account. Considering the high rate of complications with harvesting of chin grafts, more prospective trials should be done to find out whether there are other donor sites for autogenous bone which put less strain on patients.

Mandibular fractures in Townsville, Australia: incidence, aetiology and treatment using the 2.0 AO/ASIF miniplate system

In 1995 a total of 114 patients presented with 154 mandibular fractures at the Townsville General Hospital, Australia. Fifty-eight (51%) were white, 50 (44%) aboriginal, and six (5%) of other or unknown race. One-hundred-and-twenty-four of the fractures (81%) occurred in male and 30 (19%) in female patients. Most fractures (n= 128, 83%) resulted from fights. The rest being a result of road traffic accidents (10%), falls (3%), accidents caused by falling objects (3%) and sport accidents (2%). The mandibular angle (n= 66, 43%) and the symphyseal area (n= 40, 26%) were the most common fracture sites. Combined fractures were found in 30% patients (26%). Of all angle fractures, 97% were related to third molars. One-hundred-and-five patients had open reduction by an intraoral approach and stabilization by 2.0 AO/ASIF titanium miniplates and nine closed reduction. Complications included temporary sensory deficit of the mental nerve (3%), minor malocclusion (2%) and infection or dehiscence (5%). We conclude that osteosynthesis of mandibular fractures by the 2.0 AO/ASIF titanium miniplate system is reliable.

A prospective electromyographic and computer-aided thermal sensitivity assessment of nerve lesions after sagittal split osteotomy and Le Fort I osteotomy

PURPOSE

The purpose of this study was to determine the incidence of temporary and permanent sensory disturbance of the inferior alveolar nerve (IAN) after bilateral sagittal split osteotomy (BSSO) of the mandible and of the infraorbital nerve (ION) after Le Fort I osteotomy, as well as the rate of recovery of sensory function using subjective and objective measures.

PATIENTS AND METHODS

Preoperatively and after 1 week, and 1, 3, 6, and 12 months postoperatively, sensibility in the distribution of 36 IONs after Le Fort I osteotomy and 24 IANs after BSSO in 19 patients were investigated by using sharp-blunt testing, 2-point discrimination, electromyographic recording, and thermal sensitivity (Pain and Thermal Sensitivity Test Device [PATH]) tests of the Adelta and C nerve fibers.

RESULTS

With conventional clinical sharp-blunt and 2-point discrimination tests, the incidence of temporary impairment was 81% for the ION (29 of 36) and 83% for the IAN (20 of 24). The rate of permanent sensibility disturbance with conventional clinical testing was 6% for the ION and 15% for the IAN. Obvious recovery was found after 1 to 3 months for the ION, but it took 6 to 12 months for the IAN. In contrast, electromyography (EMG) testing showed lower rates of temporary sensory disturbance, namely, 54% (13 of 24) for the ION and 68% (15 of 22) for the IAN. Permanent sensory losses were not found. The results of the EMG test was confirmed by the PATH test.

CONCLUSIONS

Objective tests for sensory disturbances show lower rates than the conventional tests. For quality control, preoperative and postoperative measurement and documentation of postoperative recovery of sensation is recommended.

Role of thermography in the assessment of infraorbital nerve injury after malar fractures

We studied 45 patients with malar fractures who had some degree of infraorbital nerve deficit. Thermographic facial images failed to show any substantial changes in the temperature profiles of the affected and the normal control sides in relation to reco very of their facial sensation. Although some patients who had thermography on the day of injury showed significant temperature differences between the affected and the normal sides, these differences were probably the result of the acute inflammatory ch anges caused by the injury. We suggest that infrared thermography has little place in the assessment of infraorbital nerve deficits.