Clinical Neurosensory Testing Research Articles

Piezoelectric versus conventional techniques for orthognathic surgery: Systematic review and meta-analysis

PurposeThe purpose of this study was to perform a systematic review and meta-analysis of complications after orthognathic surgery comparing piezo-surgery with conventional osteotomy. MethodsWe conducted this study according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We performed a systematic search of PubMed, Scopus, Science Direct, Lilacs, Cochrane Central Register of Controlled Trials, Google Scholar, and OpenThesis to identify randomized and nonrandomized controlled trials (RCTs and nRCTs, respectively) comparing patient outcomes (operative time, intraoperative blood loss, postoperative swelling, pain, neurosensitivity) after orthognathic surgery by piezoelectric or conventional osteotomy. We pooled individual results of continuous and dichotomous outcome data using the mean difference (MD) and risk difference (RD) with the 95% confidence interval, respectively. ResultsThree RCTs and five nRCTs were selected. No difference in operative time was observed between piezo-surgery and conventional osteotomies. We found a decrease of intraoperative blood loss with piezo-surgery (MD −128 mL; P < 0.001) and a pooled difference in severe blood loss of 35% (P = 0.008) favouring piezo-surgery. Based on pooled individual results of studies evaluating neurosensitivity by clinical neurosensory testing, our meta-analysis showed a pooled difference in severe nerve disturbance of 25% (P < 0.0001) favouring piezo-surgery. Test for subgroup differences (I2 = 26.6%) indicated that follow-up time may have an effect on neurosensory disturbance. We found differences between piezo-surgery and conventional osteotomy at 3 months (RD 28%; P < 0.001) and 6 months (RD 15%; P = 0.001) after surgery. Meta-analyses for pain and swelling were not performed because of a lack of sufficient studies. ConclusionCurrently available evidence suggests that piezo-surgery has favorable effects on complications associated with orthognathic surgery, including reductions in intraoperative blood loss and severe nerve disturbance.

Effects of Superpulsed, Low-Level Laser Therapy on Neurosensory Recovery of the Inferior Alveolar Nerve.

The purpose of this investigation was to evaluate the therapeutic efficacy of superpulsed, low-level laser therapy (SLLLT) on neurosensory recovery of the inferior alveolar nerve (IAN) after oral surgical injury. A survey of the literature reveals the uncertainty of outcomes for the surgical management of IAN injury and the efficacy of low-level laser therapy in the treatment of IAN injury. In this study, the authors report the results for SLLLT in 57 patients affected by paresthesia of the lip, chin, gingival, and buccal regions. Each patient was subjected to 10 laser treatments, once a week, with a GaAs diode laser. Clinical neurosensory tests (soft touch, 2-point discrimination, pin prick, thermal test) and the visual analogue scale were used before every treatment to evaluate the extent of neurosensory recovery. The authors' results demonstrate that 83.3% of the patients had a significant neurosensory recovery, as evident in the objective and subjective tests. The results reported in this study indicate that SLLLT has the potential to improve neurosensory recovery in patients with IAN paresthesia.

Outcomes of Immediate Allograft Reconstruction of Long-Span Defects of the Inferior Alveolar Nerve

Contemporary management of ablative jaw defects includes not only hard and soft tissue reconstruction, but also restoration of neurosensory function. The goal of this study was to determine the outcomes of immediate reconstruction of long-span defects (≥50mm) of the inferior alveolar nerve (IAN) after ablative mandibular resection using allogeneic nerve grafts. A retrospective cohort study of patients who underwent immediate reconstruction of IAN gaps of at least 50mm with allogeneic nerve graft (AxoGen Avance, Alachua, FL) at a single academic medical center by a single surgeon (M.M.) from September 2013 to March 2015 was completed. Demographic and clinical data were collected for each patient and analyzed using clinical neurosensory testing and were reported using the Medical Research Council Scale (MRCS) for functional sensory recovery. In addition, patient subjective perception of neurosensory recovery was recorded using a visual analog scale (VAS). Subjective (VAS) and objective (MRCS) measurements of functional sensory recovery were recorded and compared across the study population. In addition, examined demographic and clinical data included patient age, gender, pathology, length of nerve allograft, and follow-up period. Of 12 with nerve repairs, 7 patients met the inclusion criteria. The average age was 34.7years (range, 18 to 61yr) and 71.4% were men. All IAN defects resulted from resection of mandibular pathology (6 benign lesions, 1 malignant lesion). Six of the 7 IAN defects were reconstructed with a 70-mm nerve allograft, and 1 nerve defect was reconstructed with a 50-mm graft. Mean follow-up time was 17.7months (range, 10 to 27.5months). Mean VAS score reported was 3.7 (range, 0 to 7). In addition, 85.7% of patients displayed return of some superficial pain and tactile sensation without over-response (S3), with 14.3% displaying good stimulation localization (S3+). The patient who displayed S3+ recovery underwent reconstruction with the 50-mm graft. Only 1 of the 7 patients had no neurosensory recovery (S0). Immediate reconstruction of the IAN with allogeneic nerve grafting of long-span defects (≥5cm) is a viable and predictable option to achieve useful functional sensory recovery.

Sensory Outcomes After Reconstruction of Lingual and Inferior Alveolar Nerve Discontinuities Using Processed Nerve Allograft—A Case Series

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. 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. 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 injuriesrepaired after 90 days. 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.

Evaluation of neurosensory disturbance following orthognathic surgery: a prospective study.

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. 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 1week, 1 and 6months 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. 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 1week, 30% at 1month, 20% at 6months and 10% at 1year 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. 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.

Sensitivity of the Inferior Lip and Chin following Mandibular Bilateral Sagittal Split Osteotomy Using Piezosurgery

Bimaxillary osteotomy, including bilateral sagittal split osteotomy, is the most commonly performed orthognathic surgical intervention in Europe and the United States. Neurosensory perturbation in the territory of the inferior alveolar nerve is a reported adverse effect of bilateral sagittal split osteotomy. Piezosurgery is a relatively new technique that allows bone to be cut while preserving soft tissues, including nerves. The purpose of this study was to assess inferior alveolar nerve function through clinical neurosensory testing after bilateral sagittal split osteotomy using Piezosurgery. Between February and September of 2004, 20 patients (40 sides) presenting with dentoskeletal deformities underwent bimaxillary osteotomy, including bilateral sagittal split osteotomy. The Mectron Piezosurgery device was used to perform all sagittal splits, with distraction being performed between the two bone valves. The inferior alveolar nerve was evaluated both objectively with clinical neurosensory testing, including pin-prick sensation, light touch sensation, and two-point discrimination tests, and subjectively at the following time points: preoperatively; at days 5, 7, and 10, postoperatively; and at the second month postoperatively. The anatomical integrity of the inferior alveolar nerve was respected in all cases. Observed normal results for the different tests at 10 days were 90, 82, and 70 percent, respectively, for pin-prick sensation, light touch sensation, and two-point discrimination. By computing scores for different clinical neurosensory tests, the authors observed between 75 and 80 percent complete neurosensory recuperation as early as the second postoperative month. Piezosurgery used for bilateral sagittal split osteotomy allows prompt recovery of inferior alveolar nerve neurosensory function within 2 months. No comparison is possible with the results using the standard technique for bilateral sagittal split osteotomy.

Efficacy of low level laser therapy on neurosensory recovery after injury to the inferior alveolar nerve.

BackgroundThe most severe complication after the removal of mandibular third molars is injury to the inferior alveolar nerve or the lingual nerve. These complications are rather uncommon (0.4% to 8.4%) and most of them are transient. However, some of them persist for longer than 6 months, which can leave various degrees of long-term permanent disability. While several methods such as pharmacologic therapy, microneurosurgery, autogenous and alloplastic grafting can be used for the treatment of long-standing sensory aberrations in the inferior alveolar nerve, there are few reports regarding low level laser treatment. This paper reports the effects of low level laser therapy in 4 patients with longstanding sensory nerve impairment following mandibular third molar surgery.MethodsFour female patients had complaints of paresthesia and dysesthesia of the lip, chin and gingiva, and buccal regions. Each patient had undergone mandibular third molar surgery at least 1 year before. All patients were treated with low level laser therapy. Clinical neurosensory tests (the brush stroke directional discrimination test, 2-point discrimination test, and a subjective assessment of neurosensory function using a visual analog scale) were used before and after treatment, and the responses were plotted over time.ResultsWhen the neurosensory assessment scores after treatment with LLL therapy were compared with the baseline values prior to treatment, there was a significant acceleration in the time course, as well as in the magnitude, of neurosensory return. The VAS analysis revealed progressive improvement over time.ConclusionLow level laser therapy seemed to be conducive to the reduction of long-standing sensory nerve impairment following third molar surgery. Further studies are worthwhile regarding the clinical application of this treatment modality.

Posttraumatic trigeminal nerve impairment: A prospective analysis of recovery patterns in a series of 103 consecutive facial fractures

To report the incidence of peripheral trigeminal nerve posttraumatic impairments and to compare different recovery patterns as observed in consideration of different fracture-related variables within 12-month follow-up. Ninety-seven consecutive patients with 103 facial fractures were included involving emergence areas of supraorbital nerve, infraorbital nerve, or the region between the mandibular and mental foramina. Presurgical and postsurgical clinical neurosensory testing sessions were performed in each patient. Results of these assessments were compared within fracture characteristics and different sites of trauma. Statistical analysis (chi-square test) was performed on clinical observations. The incidence of trigeminal nerve impairments was 70.9% (54.4% in nondisplaced fractures, 88.2% in dislocated fractures, 100% in fractures with a direct nerve injury). Severe impairment was found in direct nerve injures and in many dislocated fractures. Mean recovery time was smaller in nondisplaced fractures than in dislocated fractures. Considering fracture site, the highest incidence of initial trigeminal nerve impairment was found in midfacial nondisplaced fractures. Midfacial fractures had better prognosis than mandibular fractures, and best prognosis was encountered in nondisplaced midfacial fractures. Residual hypoesthesia persisted in 11 sides with direct nerve injury after 12 months and involved tactile and discriminative sensibilities. Recovery patterns of posttraumatic trigeminal dysfunction are related to site and type of fracture; intraoperative assessment of involvement of nerve bundles within fracture rimes was associated with an incomplete recovery at the 12th month. Impairment of temperature and nociception are highly related to a direct nerve injury.

Diagnosis and management of trigeminal nerve disorders

Diagnosis and management of trigeminal nerve disorders

Evaluation of the neurosensory deficiencies of oral and maxillofacial region following surgery

Maxillofacial neurosensory deficiencies may be caused by various surgical procedures such as tooth extraction, osteotomies, preprosthetic procedures, excision of tumors or cysts, surgery of the TMJ and surgical treatment of fractures and cleft lip/palate. These deficiencies may be intolerable for the patient, mainly because of the elective nature of the procedures such as osteotomies. In this study, a retrospective evaluation of incidence of neurosensory deficiencies (NSD) in 227 patients who underwent different kinds of surgeries in the maxillofacial region is presented. Clinical neurosensory testing such as two-point discrimination, static light touch, brush directional stroke, pin-prick, thermal discrimination and dental vitality tests were used for evaluation. All the patients were grouped according to the surgical procedures and all of them were evaluated at least one year post operation. It was concluded that osteotomies, especially sagittal split ramus osteotomies, have the highest incidence of postoperative NSD.

Evaluation of the neurosensory deficiencies of oral and maxillofacial region following surgery

Maxillofacial neurosensory deficiencies may be caused by various surgical procedures such as tooth extraction, osteotomies, preprosthetic procedures, excision of tumors or cysts, surgery of the TMJ and surgical treatment of fractures and cleft lip/palate. These deficiencies may be intolerable for the patient, mainly because of the elective nature of the procedures such as osteotomies. In this study, a retrospective evaluation of incidence of neurosensory deficiencies (NSD) in 227 patients who underwent different kinds of surgeries in the maxillofacial region is presented. Clinical neurosensory testing such as two-point discrimination, static light touch, brush directional stroke, pin-prick, thermal discrimination and dental vitality tests were used for evaluation. All the patients were grouped according to the surgical procedures and all of them were evaluated at least one year post operation. It was concluded that osteotomies, especially sagittal split ramus osteotomies, have the highest incidence of postoperative NSD.

The accuracy of clinical neurosensory testing for nerve injury diagnosis

Purpose: The accuracy of the clinical neurosensory test to diagnose trigeminal nerve injuries has never been statistically evaluated. The purpose of this study was to determine the statistical efficacy of the clinical neurosensory test using surgical findings as the “gold” standard, and to determine whether a correlation existed between the sensory impairment score obtained by preoperative testing and the degree of nerve injury found at surgery. Materials and Methods: A multisite, randomized, prospective, blinded, clinical trial was conducted on 130 patients with inferior alveolar nerve (IAN) and lingual nerve (LN) injuries. Preoperatively, patients were provided a sensory impairment score using a three-level drop-out clinical neurosensory test (NST), and blind comparisons were made with the surgical findings postoperatively. Results: The positive predictive and negative predictive values for LN-injured patients were 95% and 100%, respectively. The positive predictive and negative predictive values for IAN patients were 77% and 60%, respectively. There were statistically significant differences in the distribution of age, duration of injury, cause of injury, presence of neuropathic pain, presence of trigger pain, and degree of injury between the IAN and LN patient populations. There was a statistically significant positive relationship found between the sensory impairment score and the degree of nerve injury. Conclusions: The NST is a clinically useful method to diagnose IAN and LN injuries. However, the NST results are less efficient for IAN injuries than LN injuries, and have a high incidence of false-positive (23%) and false-negative (40%) results when testing patients with IAN injuries. The different rates of statistical efficiency between the two groups of patients may be attributable to differences in prevalence and biologic covariates.

The accuracy of clinical neurosensory testing for nerve injury diagnosis

The accuracy of clinical neurosensory testing for nerve injury diagnosis

The mental nerve blink reflex in the diagnosis of lesions of the inferior alveolar nerve following orthognathic surgery of the mandible

The purpose of this study was to evaluate the diagnostic value of a new modification of the blink reflex test with stimulation of the distribution of the mental nerve in iatrogenic lesions of the inferior alveolar nerve. The test was performed on 23 patients undergoing orthognathic surgery of the mandible, most of them (20) with bilateral sagittal split osteotomies. The function of the inferior alveolar nerve was studied preoperatively, and 2 weeks, 2 months, 6 months and 1 year postoperatively with both mental nerve blink reflex test and clinical neurosensory testing. The objective electrophysiological test proved to be useful in the diagnosis and follow-up of sensory impairment of the inferior alveolar nerve. The results of the mental nerve blink reflex test and clinical neurosensory testing were closely related. The results of the two tests did not differ statistically significantly in the two first postoperative examinations. The positive predictive value of the mental nerve blink reflex test was better than that of clinical neurosensory testing: an initially abnormal reflex response predicted persistent subjective sensory symptoms after one year more reliably than did altered sensation at the first two examinations. Irrespective of the possible coexistent sensory symptoms and signs, a normal mental nerve blink reflex within 2 months after operation also predicted a reasonably good sensory recovery at 1 year.

Evaluating function of the inferior alveolar nerve with repeated nerve conduction tests during mandibular sagittal split osteotomy

Purpose: This article evaluates a new intraoperative recording technique for measuring the sensory nerve conduction velocity (SNCV) of the human inferior alveolar nerve (IAN) during orthognathic surgery of the mandible to assess the effects of intraoperative strain on function of the IAN. Materials and Methods: The new test was successfully applied in 10 patients during bilateral sagittal split osteotomy of the mandible (20 IANs). The recordings were made with active wire electrodes at foramen ovale and stimulation was done at the mental foramen with two monopolar needle electrodes. The sensory nerve action potentials (SNAP) were recorded intraoperatively at three stages: 1) before the split, 2) after splitting of the mandible and possible mobilization of the IAN from the proximal bone fragment, and 3) at the end of the operation after fixation of the proximal and distal fragments with screws. Results: The SNCV values (mean 64.1 m/sec) were obtained in all 20 nerves at stage 1, with no significant differences between the sides in latency or amplitude of the SNAPs. The SNAPs remained stable in the IANs not exposed during the operation. In the remaining nerves, the most obvious and statistically significant changes indicating nerve injury occurred between stages 1 and 2. Partial transsection and mobilization of the IAN were equally potent in bringing about abnormal results in objective neurophysiologic tests as well as subjective sensory disturbances. The results of the intraoperative SNCV recordings correlated well with the findings of the mental nerve blink reflex tests conducted 2 weeks after the operation, whereas comparison of the results of clinical neurosensory testing with the intraoperative events and SNCVs were more inconsistent. Conclusions: Recording of the SNCV offers a useful objective tool for the examination of the IAN both intraoperatively and in clinical diagnosis.

Clinical neurosensory testing: Practical applications

A relatively large percentage of the practicing oral and maxillofacial surgeon's patients experience some degree of neurosensory impairment as a normal concomitant of major surgery. Additionally, some patients develop neurosensory disturbances unexpectedly following routine surgical procedures. This report describes a practical approach to evaluating these individuals, which is essential in making intelligent decisions regarding the objective nature of the nerve injury, potential for recovery, and/or possible need for secondary microneurosurgical intervention.