Lower Lip Sensation Research Articles

Assessment of the Impact of Different Surgical Techniques on Nerve Function and Sensation after Maxillofacial Surgery.

One potential long-term side effect of surgery in the oral and maxillofacial region is neurosensory impairment. Due to their physical proximity to the surgical location, the lingual nerve (LN) and inferior alveolar nerve (IAN), two sensory segments of the trigeminal nerve, are always susceptible to damage during third molar extraction. Assessment of the impact of different surgical techniques on nerve function and sensation after maxillofacial surgery. There was retrieval of information from medical records of study participants regarding the presence of symptoms like paresthesia, numbness, loss of sensation in lower lip, difficulty in movement of tongue, and all other findings observed after 7 days of surgical procedures. Clinically neurosensory examinations were utilized to assess nerve damage. Pinprick testing and the two-point discrimination test were used. Seven male patients were found to have damage to LN while nine males suffered damage to trigeminal nerve. 12 female patients were found to have damage to LN while 16 females suffered damage to trigeminal nerve. In total 19 patients suffered damage to LN while 25 patients suffered damage to trigeminal nerve. The incidence of LN damage was 9.5%, and the incidence of trigeminal nerve damage was 12.5%.

EFFECTIVENESS OF PHENTOLAMINE MESYLATE IN REVERSAL OF LOCAL ANESTHESIA: SYSTEMATIC REVIEW AND META-ANALYSIS.

The aim of the present paper is to summarize the effectiveness of Phentolamine mesylate on the reversal of local anesthesia (LA). Seven electronic databases were searched for randomized clinical trials in patients who received LA (population) and either received a Phentolamine injection (intervention) after LA compared to placebo or sham (control) to cause a return of normal sensation (outcome). Risk of bias assessment was performed using Cochrane risk of bias assessment tool 2.0. The hazard ratio (HR) was calculated as the event (time to return to the normal sensation) was a time-dependent event, as well as the weighted mean difference (WMD), was computed. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of the evidence. Ten studies met our inclusion criteria and were included in this review. After pooling the results quantitatively, the value of the HR in the tongue was 0.56 (95% CI: 0.41-0.75, P<.001); in lower lip, the value was 0.56 (95% CI: 0.38-0.83, P = .004) and for upper lip, the value was 0.50 (95% CI: 0.31-0.80, P = .004). The WMD for the time to return for normal sensation was -47.71min for the tongue (95% CI: -73.63 to -21.80min, P<.001), -73.29min for lower lip (95% CI: -88.41 to -58.16min, P<.001) and -86.86min for upper lip (95% CI: -101.16 to -72.57min, P<.001). There is a high certainty of evidence that patients who have been administered local anesthesia may achieve faster recovery of normal sensation in tongue, and moderate certainty of evidence for return of normal sensation in lower lip and upper lip, if Phentolamine was administered after the local anesthesia. The adverse effects were reported in a few studies and were minor, not necessitating any medical intervention. Phentolamine might be a useful adjunct in patients who desire an earlier return of normal sensation and function after local anesthesia. Future research should be directed to study the cost-effectiveness or dental patient-reported outcomes of Phentolamine after local anesthetic injections.

Promotion effect of TGF-β-Zfp423-ApoD pathway on lip sensory recovery after nerve sacrifice caused by nerve collateral compensation

Resection of oral and maxillofacial tumors is often accompanied by the inferior alveolar nerve neurectomy, resulting in abnormal sensation in lower lip. It is generally believed that spontaneous sensory recovery in this nerve injury is difficult. However, during our follow-up, patients with inferior alveolar nerve sacrifice showed different degrees of lower lip sensory recovery. In this study, a prospective cohort study was conducted to demonstrate this phenomenon and analyze the factors influencing sensory recovery. A mental nerve transection model of Thy1-YFP mice and tissue clearing technique were used to explore possible mechanisms in this process. Gene silencing and overexpression experiments were then conducted to detect the changes in cell morphology and molecular markers. In our follow-up, 75% of patients with unilateral inferior alveolar nerve neurectomy had complete sensory recovery of the lower lip 12 months postoperatively. Patients with younger age, malignant tumors, and preservation of ipsilateral buccal and lingual nerves had a shorter recovery time. The buccal nerve collateral sprouting compensation was observed in the lower lip tissue of Thy1-YFP mice. ApoD was demonstrated to be involved in axon growth and peripheral nerve sensory recovery in the animal model. TGF-β inhibited the expression of STAT3 and the transcription of ApoD in Schwann cells through Zfp423. Overall, after sacrificing the inferior alveolar nerve, the collateral compensation of the ipsilateral buccal nerve could innervate the sensation. And this process was regulated by TGF-β-Zfp423-ApoD pathway.

Sensory Outcomes for Inferior Alveolar Nerve Reconstruction with Allograft following Free Fibula Mandible Reconstruction.

As patient survival with head and neck cancer has improved, treatment goals have had to evolve to focus on improving quality of life. Traditionally, patients who have undergone mandibulectomy are left with an insensate chin and lower lip secondary to resection of the inferior alveolar nerve (IAN). The purpose of this study was to critically evaluate the authors' initial experience using processed nerve allografts (PNA) for IAN reconstruction following oncologic mandibulectomy and reconstruction with free fibula osteocutaneous flaps and to assess their patients' sensory outcomes. The authors performed a retrospective review of the first 32 patients who underwent immediate IAN reconstruction with PNA at the time of oncologic mandibulectomy and mandible reconstruction with free fibula osteocutaneous flaps at The University of Texas M. D. Anderson Cancer Center over a 1-year period. Semmes-Weinstein filament sensory testing was conducted at multiple surgical follow-up appointments to evaluate the quality of sensory recovery. Thirteen of the 32 patients underwent postoperative Semmes-Weinstein filament testing. All 13 patients demonstrated partial return of sensation. At a mean follow-up of 8.33 months, the average level of sensation was 60.93% that of the unaffected side of the lower lip. Patients were consistently afforded improvement in lower lip sensation using PNA-based IAN grafting as an adjunct to free fibula-based mandible reconstruction. The procedure adds no additional surgical morbidity and has shown consistent positive results.

Balcony genioplasty: a novel technique for better esthetic results in patients with deep mentolabial fold

BackgroundTo introduce a novel technique for advancement genioplasty helping surgeons to avoid soft tissue difficulties especially in short-faced patients with deep mentolabial fold and everted lower lip.Case presentationIn a trapezius-shaped, osteotomy was performed in the chin region. The mobilized segment was advanced, and the existing gap was grafted using interpositional allograft materials. Each side had been fixated by three-hole plates and two screws. The outcomes revealed no change in lower anterior teeth vitality. The patients did not report any changes of sensation in lower lip and chin either. The measurements indicated no increase in depth of mentolabial fold in patients undergoing this surgical technique. The postoperative evaluation showed a successful esthetic outcome for the patient and the surgeon concurrently.ConclusionBased on our experience, the authors concluded that the Balcony technique is a simple and reliable procedure for patients with a deep mentolabial fold.

Evaluation of accuracy and sensory outcomes of mandibular reconstruction using computer-assisted surgical simulation

PurposeTo introduce a modified protocol for mandibular reconstruction and evaluate the protocol using a standardized assessment method. MethodThis retrospective study involved a case series of nine patients who underwent mandibular reconstruction between 2015 and 2017. The modular protocol comprised three novel modifications in terms of computer-assisted surgical simulation (CASS); surgical template (ST), and surgical procedure. The standardized postoperative evaluation consisted of operation time, part comparison analysis (PCA), facial symmetry, and mechanical quantitative sensory testing. ResultsThe surgery successfully removed the affected mandible and preserved the inferior alveolar neurovascular bundle (IANB). PCA revealed that the mean error and standard deviation were 0.92 and 0.96 mm, respectively, for all mandibular surface sites. Follow-up results showed good facial symmetry, existence of sensation in lower lip, and no significant differences in pulp vitality between both sides (p = 0.181). Also, the results showed a reduction in the overall operating time. ConclusionThe modified mandibular reconstruction method used in this study could repair lateral mandibular defects and preserve the sensory function of the chin and lower lip.

A Prospective Study of Chin Bone Graft Harvesting for Unilateral Maxillary Alveolar Cleft During Mixed Dentition

The chin is a common donor site for alveolar cleft bone grafting. The amount of bone available at this site can be limited, because conservative harvesting with mixed dentition must consider the incisive nerve, the unerupted mandibular canine, and the integrity of the inferior mandibular border. Patients with nonsyndromic unilateral alveolar cleft in the mixed dentition stage were selected for this study. The volume of bone obtained from the mandibular symphysis (symphysis menti), degree of alteration in lower lip sensation, anterior tooth vitality, remaining bone in the alveolar cleft, and bone defects at the donor site 1year after surgery were evaluated. Eighteen patients were enrolled in this study. The mean volume of bone harvested from the symphysis was 2.1mL (range, 1.6 to 2.3mL). For all cases, the bone volume harvested from the symphysis was insufficient to fill the alveolar cleft defect, and allograft had to be added to completely fill the cleft. Allograft was admixed in the range of 0.5 to 1mL with autogenous bone harvested from the mandible. Lower lip sensation and vitality of the anterior teeth of the mandible were within the normal range 1year after surgery in all cases. Fourteen of 18 patients (77.8%) had normal bone height or bone height at least three fourths of the expected height in the grafted alveolar cleft after 1year; only 10% of the defect remained in the mandible. The amount of bone yielded by conservative monocortical bone harvest from the mandibular symphysis during the mixed dentition stage for unilateral alveolar cleft bone grafting is not sufficient in volume and should be mixed with allograft. However, donor site morbidity is low with this approach.

Attachment Rate of the Inferior Alveolar Nerve to Buccal Plate During Bilateral Sagittal Split Osteotomy Influences Self-Reported Sensory Impairment

This study was aimed to investigate a modified buccal osteotomy technique and whether the integrity of the lingual part of the lower border influences the attachment of the neurovascular bundle to the proximal segment of the mandible during a sagittal split osteotomy without increasing the number of bad splits. The presence of self-reported sensibility disturbance in the lower lip at the last follow-up visit was assessed. This study included 220 and 133 patients with bilateral sagittal split osteotomy undergoing the classical and the new modified buccal osteotomy techniques, respectively. In the new technique, the lower border is divided into a lingual fragment that remains incorporated in the tooth-bearing fragment and a buccal fragment that comes with the proximal fragment (buccal plate). In the classical technique, the inferior alveolar nerve was attached to the proximal segment of the mandible in more than one third of operation sites (36.36% on the right and 40.91% on the left) compared with less than one fourth of the operation sites using the new technique (9.73% on the right and 23.01% on the left). The overall figure of self-reported changed sensibility was 09.40% (12/128) in the new technique compared to 15.12% in the classical technique. We present a suitable improvement to the classical buccal osteotomy technique that allows less manipulation and injury of the inferior alveolar nerve with consequent reduction in self-reported postoperative changes in lower lip sensation

Self-reported hypoesthesia of the lower lip after sagittal split osteotomy

Sagittal split osteotomy may result in sensory impairment of the inferior alveolar nerve; altered sensation in the lower lip varies from patient to patient. We evaluated individual and intraoperative risk factors of sagittal split osteotomy and correlated these findings with self-reported postoperative changes in lower-lip sensation. Follow-up data for 163 consecutive patients who underwent a bilateral sagittal split osteotomy were assessed for self-reported sensibility disturbances in the lower lip at the last follow-up visit. These self-reports were categorized as normal, hypoesthesia, hyperesthesia, or slightly diminished sensation in the central area of the chin. The overall rate of self-reported changed sensibility was 15.1% (49/324; 13.0% on the right side and 17.3% on the left side). Of 16 patients (9.9%) who experienced hypoesthesia on the right side and 25 patients (15.4%) who experienced hypoesthesia on the left side, 10 experienced bilateral hypoesthesia (31 patients total, 19.1%). Genioplasty and age at surgery were significant predictors of hypoesthesia; a 1-year increase in age at surgery increased the odds of hyposensitivity by 5%, and the odds of hypoesthesia in patients with concurrent genioplasty were 4.5 times higher than in patients without genioplasty. Detachment of the nerve at the left side, but not at the right side, was significantly correlated with hypoesthesia.

Evaluation of an innovative computer‐assisted sagittal split ramus osteotomy to reduce neurosensory alterations following orthognathic surgery: a pilot study

Sagittal split ramus osteotomy (SSRO) can be associated with postoperative neurosensory disturbances. This study aimed to evaluate the effectiveness of computer-assisted SSRO in reducing the incidence and severity of neurosensory alterations, using a surgical guide fabricated by computer-aided design and rapid prototyping (to guide bone cutting lateral to the inferior alveolar nerve). A prospective double-blind, randomized controlled, clinical trial of computer-assisted SSRO vs conventional SSRO (assigned in a split-mouth design) in eight patients, mean age 23 (range 18-30) years, who participated in one session preoperatively and three sessions at 1 week and 1, 3 and 6 months postoperatively. At each session, subjective oral sensation was scored and quantitative sensory tests were performed. Neurosensory changes were compared between the two sides. The results showed that on the computer-assisted SSRO sides, patients had lower postoperative abnormal thresholds for the Semmes-Weinstein monofilaments on lower lip and chin (p < 0.05 at 3 months) and for the two-point discrimination on lower lip (p < 0.05 at 1 week) and chin (p < 0.05 at 6 months), with fewer abnormal self-reported changes in lower lip sensation (p < 0.05 at 1 week) after surgery. These findings imply that computer-assisted SSRO is associated with better levels of neurosensory function after surgery.

Evaluation of the change of lower lip sensation after inferior alveolar nerve block by using the electric pulp tester

J Korean Assoc Oral Maxillofac Surg 2011;37:464-9) Evaluation of the change of lower lip sensation after inferior alveolar nerve block by using the electric pulp tester Myong-Suk Ku, Jin Wook Kim, Young Hoon Jeon, Tae Geon Kwon, Sang Han Lee Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, Korea Introduction: As dental implant surgery is becoming increasingly popular, it has become one of the causes for the hypesthesia of the inferior alveolar nerve, along with other surgical procedures, such as a third molar extraction. In addition, it tends to cause legal problems between the operator and patient. Therefore, there must be a proper method that is reliable, objective and economical to assess the nerve impairment. For this reason, an attempt was made to use an Electric Pulp Tester to assess inferior alveolar nerve block anesthesia. Materials and Methods: Thirty patients were tested. Electric pulp testing of the lower jaw skin was performed at the three different times, before anesthesia, at the onset of sensory changes and after 15 minutes waiting from the onset, and on the 10 points of the chin, which produced 10 sections on the skin area. Results: Twenty seven patients (90%) could feel the electric stimulus on the chin at all 10 points before local anesthesia and the scores represent the statistical differences between the right and left points except R4 and L4. After anesthesia, the difference between the right and left points (L3-R3, L4-R4, L5-R5) increased significantly with time but two points (L2, R2) showed no significant difference. The scores on the left chin (L3, L4, L5) increased, whereas the other points (R1-R5, L1, L2) showed no significant differences. Conclusion: This study highlights the potential clinical use of an electric pulp tester for an assessment of inferior alveolar nerve impairment.

Lateral Lip-Splitting Approach for Total and Subtotal Maxillectomy

This study reviewed our patients who underwent maxillectomy by the lateral lip-splitting approach and evaluated postoperative outcomes. Thirty-six patients with diseases in the maxilla, maxillary gingiva, and hard palate who underwent total or subtotal maxillectomy by the lateral lip-splitting approach. The marginal mandibular branch of facial nerves were dissected and preserved before and after the procedure to split the lateral lower lip in all patients. Seventeen patients were reconstructed with free vascularized flaps. Postoperative radiotherapy was administered in 26 patients. The patient's self-assessment and examiner's evaluation were included in the postoperative assessment. The patient's self-assessment included answering a questionnaire, that included evaluation of buccal scar, symmetry of cheilion, lower lip movement, oral incontinence, and lower lip sensation. The examiner's evaluation included assessment of the functions of the facial nerve. All tumors were removed en bloc with sufficient safety margins except 1 adenoid cystic carcinoma in maxilla. The average mouth opening was 3.81 cm. According to the results classified as good, fair, and poor by questionnaires, most of the 36 patients thought their results were good or fair. Most of the patients were high scores, according to the examiner's evaluation. The overall 5-year survival and local control rates for patients with malignant tumors were 76.7% and 85.8%, respectively. The local and regional recurrent and distant metastasis rate was 12.9%, 6.5%, and 19.4%, respectively. The lateral lip-splitting approach is an acceptable and optional approach for maxillectomy because of wide exposure, satisfied function, inconspicuous scar, and preservation of facial nerve.

Risk Factors Affecting Somatosensory Function After Sagittal Split Osteotomy

The aim of this study was to evaluate potential individual and intraoperative risk factors associated with bilateral sagittal split osteotomy (BSSO) and to correlate the findings with postoperative changes in somatosensory function. A total of 18 men and 29 women (mean age, 31 +/- 10 years) scheduled for BSSO participated in 1 session before BSSO and 5 sessions after BSSO (at 2 and 14 days and 3, 6, and 12 months). At each session, subjective oral sensation was scored and quantitative sensory tests were performed. The results showed that complete exposure and free dissection of the inferior alveolar nerve during BSSO increased self-reported changes in lower lip sensation and lower lip tactile threshold after BSSO (P < .01). Long surgical movements reduced self-perceived jaw-opening function and impaired 2-point discrimination (P < .05). Significant correlations were noted between preoperative values for somatosensory function and changes in these variables after BSSO. Patients with low sensory thresholds before BSSO experienced more impairment than those patients with higher preoperative sensory thresholds. These findings imply that somatosensory function after BSSO is dependent on both intraoperative risk factors and preoperative sensation levels.