Sensory nerve morbidity following Le Fort I osteotomy

Magnetoencephalographic evaluation of repaired lip sensation in patients with cleft lip

Background

Cleft lip is the most common congenital anomaly worldwide. Nevertheless, lip somatosensory characteristics of patients with cleft lip after cheiloplasty have not yet been determined. The present study used magnetoencephalography to objectively evaluate the lip sensation in patients with unilateral cleft lip to establish a new objective evaluation method.

Methods

Participants were 15 patients with unilateral cleft lip after cheiloplasty (UCL group), and 30 healthy young subjects (control group). Five points of the upper and lower lips were stimulated electrically to measure somatosensory evoked magnetic fields (SEFs). The sources of the magnetic fields were modeled as single equivalent current dipoles (ECDs). ECDs located on the central sulcus by superimposition on magnetic resonance images were analyzed. Latency and intensity at 50–75 ms (cP60m) observed in the UCL group were compared with those in the control group. Thresholds of tactile stimuli in both groups were obtained using Semmes–Weinstein monofilaments for subjective sensory evaluation.

Results

No significant difference was found in the intensity of the cP60m or subjective evaluation between the groups. However, the latency of the cP60m was significantly longer in the upper lip of the UCL group than in the control group.

Conclusions

SEFs showed a difference in lip sensation between the UCL group and the control group, suggesting that longer latency might be caused by the effects of surgical scarring on the neurotransmission pathway. These results suggest SEFs as useful for the objective evaluation of lip sensations. This study might improve future surgical procedures and lip functions of patients with cleft lip.

Surgical procedures for correcting vertical maxillary excess: A review

INTRODUCTION

Vertical maxillary excess, a common orthodontic problem that leads to long faces and open bites, can be repositioned with a Le Fort I osteotomy. However, the Le Fort I osteotomy poses the risk of a variety of complications including descending palatine artery (DPA) injury. Although several Le Fort I osteotomy modifications were reported to avoid complications associated with this osteotomy, only a few of such studies were conducted in Japan, and details remain scarce.

PATIENTS AND METHODS

We performed a literature review regarding modifications of Le Fort I osteotomies, including Le Fort I with a horseshoe osteotomy, modified horseshoe osteotomy, unilateral horseshoe osteotomy, pyramidal osteotomy, and U-shaped osteotomy. We identified eight relevant studies conducted in Japan; one study did not provide the number of patients examined. The 77 patients (seven studies) with vertical maxillary excess who underwent orthognathic surgery were ≥17 years old.

DISCUSSION

There were no severe complications after the modified Le Fort I osteotomies. The postoperative maxillary changes obtained by the conventional horseshoe, modified horseshoe, unilateral type of horseshoe, pyramidal, and U-shaped osteotomies were nearly repositioned to the planned position and remained stable for ≥12 months post-surgery.

CONCLUSION

Our review indicates that preserving the DPA can lower the incidence of intra- and post-operative complications. Each modification of the Le Fort I osteotomy (i.e., conventional horseshoe, modified horseshoe, unilateral horseshoe, pyramidal, and U-shaped osteotomy) has its respective advantages and indications.

Pyramidal and posterior osseous release for maxillary superior/posterior mobilization using an ultrasonic bone-cutting device after Le Fort I osteotomy

AIM

The purpose of this study was to evaluate the efficiency of pyramidal and posterior osseous release (PPOR) for maxillary impaction using an ultrasonic bone-cutting device after Le Fort I (LFI) osteotomy.

MATERIALS AND METHODS

In total, 31 Japanese adults with jaw deformities, diagnosed as having maxillary excess with mandibular prognathism or deficiency, underwent LFI osteotomy and bilateral sagittal split osteotomy. The patients were divided into two groups: a trimming group (15 patients, four men and 11 women; mean age 24.8 years) and a PPOR group (16 patients, seven men and nine women; mean age 22.8 years). In the trimming group, osseous interference around the descending palatine artery (DPA) was removed using forceps, rounding bur, and reciprocating rasp. The PPOR technique was used to remove osseous fragments created by V-shaped osteotomy around the DPA following vertical osteotomy behind the DPA using an ultrasonic bone-cutting device (Variosurg 3; NSK, Tochigi, Japan). The operative times for maxillary osteotomy, total operative times (including bilateral sagittal split osteotomy), and total blood loss were assessed.

RESULTS

The mean planned amounts of maxillary impaction were 4.37 ± 1.27 mm in the trimming group and 4.38 ± 1.36 mm in the PPOR group (p = 0.98). The mean maxillary operative time for the PPOR group was significantly shorter, by 25.5% (p < 0.001). Total operative time for the PPOR group was also significantly shorter, by 24.3% (p < 0.001). Mean blood loss was significantly lower in the PPOR group than in the trimming group (p = 0.003).

CONCLUSION

The PPOR technique for maxillary impaction after LFI osteotomy shortened the operative time and enabled secure reduction of the maxilla in patients who required the treatment of maxillary impaction with preservation of the DPA bundle.

Early, Computer-Aided Design/Computer-Aided Modeling Planned, Le Fort I Advancement With Internal Distractors to Treat Severe Maxillary Hypoplasia in Cleft Lip and Palate

Traditionally, maxillary hypoplasia in the setting of cleft lip and palate is treated via orthognathic surgery at skeletal maturity, which condemns these patients to abnormal facial proportions during adolescence. The authors sought to determine the safety profile of computer-aided design/computer-aided modeling (CAD/CAM) planned, Le Fort I distraction osteogenesis with internal distractors in select patients presenting at a young age with severe maxillary retrusion. The authors retrospectively reviewed our "early" Le Fort I distraction osteogenesis experience-patients performed for severe maxillary retrusion (≥12 mm underjet), after canine eruption but prior to skeletal maturity-at a single institution. Patient demographics, cleft characteristics, CAD/CAM operative plans, surgical complications, postoperative imaging, and outcomes were analyzed. Four patients were reviewed, with a median age of 12.8 years at surgery (range 8.6-16.1 years). Overall mean advancement was 17.95 + 2.9 mm (range 13.7-19.9 mm) with mean SNA improved 18.4° to 87.4 ± 5.7°. Similarly, ANB improved 17.7° to a postoperative mean of 2.4 ± 3.1°. Mean follow-up was 100.7 weeks, with 3 of 4 patients in a Class I occlusion with moderate-term follow-up; 1 of 4 will need an additional maxillary advancement due to pseudo-relapse. In conclusion, Le Fort I distraction osteogenesis with internal distractors is a safe procedure to treat severe maxillary hypoplasia after canine eruption but before skeletal maturity. Short-term follow-up demonstrates safety of the procedure and relative stability of the advancement. Pseudo-relapse is a risk of the procedure that must be discussed at length with patients and families.

Anatomic basis of Le Fort 1 impaction osteotomy: a radiological study

PURPOSE

In Le Fort 1 osteotomy when a maxillary impaction is necessary, surgeons have to face different anatomical problems. (1) To determine the best bone resection route, they have to consider the situation of dental roots, infraorbital foramen and maxillary artery. (2) In case of Le Fort 1 osteotomy combined with a mandibular sagittal split osteotomy, the palate has to be replaced in horizontal position although there is no anatomical landmark. (3) In case of Gummy smiles, it can be due to either long face or short upper lip. The main objective was to identify safe bony landmarks to perform a Le Fort I osteotomy and to find a reliable way for repositioning the palate horizontally; the secondary objective was to determine the upper lip normal length.

METHODS

The study was based on 178 facial CT examinations. The following parameters have been used: the vertical length of the upper lip, the vertical heights of the anterior nasal spine, the canine and molar roots, the inferior limit of the pterygomaxillary fossa and the vertical height of the infraorbital foramen on both sides.

RESULTS

The vertical length from the subnasal point to the upper vermilion was 15.06 ± 3.09 mm, and to the junction of the upper and lower lips was 23.94 ± 3.79 mm. The vertical length from the anterior nasal spine to the incisor alveolar border was 19.70 ± 3.17 mm. The height of the canine root was 17.11 ± 2.60 mm. The height of the highest lateral root of first or second maxillary molars was 11.71 ± 1.83 mm. The vertical length from the inferior limit of the pterygomaxillary fossa (pti point) to the alveolar border of the pterygomaxillary suture was 19.86 ± 3.45 mm. The height from the center of the infraorbital foramen to the alveolar border of the maxilla on a vertical line was not statistically different on right and left sides.

CONCLUSIONS

According to our results, in impaction Le Fort 1 osteotomy, the bone resection must pass 20 mm above the alveolar border in canine area, and 15 mm above the alveolar border in molar area. The resection has to end less than 20 mm above the inferior border of the pterygomaxillary suture. The vertical height of the infraorbital foramen is a consistent landmark for repositioning of the palate in a horizontal plane.

[Recovery of maxillary tooth sensibility after Le Fort I osteotomy]

INTRODUCTION

Upper alveolar nerves, when injured during Le Fort I osteotomies, alter maxillary tooth sensitivity. We had for aim to analyze post-operative maxillary tooth sensitivity recovery.

MATERIAL AND METHODS

We conducted a prospective study in a series of patients having undergone Le Fort I osteotomy, with, or without mandibular osteotomy or intermaxillary disjunction (IMD). The direction and range of displacement of the maxillary bone were recorded. One tooth in each alveolar sector (incisivocanine, premolar, molar) was tested with an electric stimulator for each patient. The tests were performed before (D-1), and after surgery (D2 or day+2, D+15, M2 (or month +2), M3, and M6).

RESULTS

Twenty-two patients were included. Among the tested teeth, 91.9 % were sensitive at D-1. At D2, only 12.7 % of teeth were sensitive. At D15, M2, M3, and M6, the sensitivity was respectively 33.3 %, 43.1 %, 50 %, and 61.8 %. The recovery of sensitivity was faster in young patients (under 35 years of age) and for upper middle and superior alveolar nerves. There was no difference regarding the direction of maxillary movement.

DISCUSSION

Among the teeth that were sensitive before surgery, 87.3 % had not regained sensitivity at D2. The recovery of sensitivity increased at D15. A great displacement of the maxillary bone was an aggravating factor for loss of tooth sensitivity.

Evaluation of Post-operative Complication Rate of Le Fort I Osteotomy: A Retrospective and Prospective Study

Le Fort I osteotomy has become a routine procedure in elective orthognathic surgery. This procedure is often associated with significant but rare post-operative complications. The study was conducted to evaluate the rate of post-operative complications following conventional Le Fort I osteotomy. Twenty-five healthy adult patients who had to undergo Le Fort I osteotomy without segmentalization of maxilla were included in the study based on indications of surgery. All the patients were followed up for a period of 6 months post-operatively to assess the rate of various post-operative complications such as neurosensory deficit, pulpal sensibility, maxillary sinusitis, vascular complications, aseptic necrosis, unfavourable fractures, ophthalmic complications and instability or non-union of maxilla, etc. The results of our study showed a post-operative complications rate of 4 %. Neurosensory deficit and loss of tooth sensibility were the most common findings during patient evaluation at varying follow-up periods while one patient presented with signs and symptoms of maxillary sinusitis post-operatively. Neurosensory as well as sinusitis recovery took place in almost all the patients within 6 months. It was concluded that thorough understanding of pathophysiological aspects of various complications, careful assessment, treatment planning and the use of proper surgical technique as well as instrumentation may help in further reducing the complication rate.

Surgical risk factors and maxillary nerve function after Le Fort I osteotomy

PURPOSE

Data on intraoperative risk factors for long-term postoperative complications after Le Fort I osteotomy (LFO) are limited. The aim of this study was to describe prospectively the overall postoperative changes in maxillary nerve function after LFO, and to correlate these changes with a number of possible intraoperative risk factors.

PATIENTS AND METHODS

Twelve men and 13 women (mean +/- standard deviation: aged 25+/-10 years) participated in 4 sessions: 1 before LFO (baseline), and the rest at 3, 6, and 12 months after LFO. At each session, somatosensory sensitivity was assessed for the skin, oral mucosa, and teeth, using quantitative sensory tests at either 1 cutaneous point or on a 5 x 5 point matrix reproduced on the skin. In addition, all patients were asked to report their perceived differences in somatosensory sensitivity and their overall satisfaction with the LFO.

RESULTS

The thresholds of tactile stimuli on the gingiva and palate were increased 12 months after LFO (P< .001). Significant increases in 2-point discrimination detection thresholds (P< .01) and increased sensitivity to heat (P< .01) and cold (P< .001) in the infraorbital region were also recorded 12 months after LFO. Correspondingly, self-reported complaints of changed sensation under the eyes (P< .01), upper lip (P< .01), gingiva (P< .001), palate (P< .01), and teeth (P< .01) were reported during the entire postoperative period. Intraoperative risk factors were identified and correlated with postoperative changes in somatosensory sensitivity. Segmentation of the maxilla was associated with an increase in tactile thresholds at the palate and gingiva (P< .05), as were self-reported complaints involving the palate and gingiva (P< .001), whereas maxillary impaction was related to lower-tooth pulp pain thresholds when compared with maxillary lowering (P< .01). All patients expressed satisfaction with LFO, despite signs of somatosensory disturbances in up to 64% of patients.

CONCLUSION

Numerous changes in postoperative somatosensory function are to be expected after LFO. In most patients, these changes are minor, and some are dependent on intraoperative procedures. Nonetheless, all patients reported satisfaction with the surgical results, and would recommend the procedure to others.

Complications of Orthognathic Surgery

Complications in orthognathic surgery may stem from occurrences at anyone of many time points during the course of the patient's treatment: preoperative judgment and planning, perioperative orthodontic care, or intraoperatively. This article specifically addresses those complications that arise as a result of intraoperative technique. Such complications may broadly be characterized as airway, vascular, neurologic, infectious, skeletal, or aesthetic in nature. For each type, specific complications, their prevention, and their treatment are discussed.

Evaluation of upper lip hypoesthesia with a trigeminal somatosensory-evoked potential following Le Fort I osteotomy in combination with mandibular osteotomy

PURPOSE

The purpose of this study was to objectively evaluate hypoesthesia of the upper lip following Le Fort I osteotomy in combination with mandibular osteotomy with trigeminal somatosensory evoked potential (TSEP).

SUBJECTS AND METHODS

The subjects consisted of 25 patients with mandibular prognathism with maxillary retrognathism mandibular prognathism with or without asymmetry, who underwent Le Fort I osteotomy in combination with sagittal split ramus osteotomy (SSRO) or intraoral vertical ramus osteotomy (IVRO). Trigeminal nerve hypoesthesia at the region of the upper lip was assessed bilaterally by the TSEP method. The electrodes were placed exactly above the highest point of the vermilion border and on the mucosa of the upper lip. An electroencephalograph recording system (Neuropack Sigma; Nihon Koden Corp., Tokyo, Japan) was used to analyze the potentials. Each patient was evaluated preoperatively and then postoperatively at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year.

RESULTS

The average measurable period and standard deviation of TSEP of the upper lip was 7.8 +/- 10.7 weeks following Le Fort I osteotomy, TSEP of the lower lip was 4.6 +/- 9.2 weeks in the patients who underwent SSRO with Le Fort I osteotomy, and 1.2 +/- 0.4 weeks in the patients who underwent IVRO with Le Fort I osteotomy.

CONCLUSION

This study objectively proved that hypoesthesia could appear in the upper lips following Le Fort I osteotomy with TSEP. The measurable period for the upper lip following Le Fort I osteotomy tended to be longer than that for the lower lip in the patients who underwent SSRO and IVRO with Le Fort I osteotomy.

Human gingival and pulpal blood flow during healing after Le Fort I osteotomy

PURPOSE

The occurrence of a hypervascular period during healing after orthognathic surgery has not been investigated rigorously in human pulpal and gingival tissues. This study used laser Doppler flowmetry to investigate the effects of Le Fort I osteotomy on maxillary pulpal and gingival blood flow between the first and third week after surgery.

PATIENTS AND METHODS

Pulpal blood flow was recorded in maxillary incisors, and gingival blood flow was assessed from a site slightly apical to the interdental papilla of the maxillary central incisors in 10 patients who were undergoing a Le Fort I osteotomy, 10 patients who were undergoing a mandibular osteotomy, and 10 nonsurgical control subjects who were not undergoing orthodontic treatment. Blood flow measurements were made before surgery and at intervals between 7 and 10 days, 14 and 17 days, and 21 and 24 days after surgery. The nonsurgical control subjects were tested at similar intervals.

RESULTS

Baseline gingival and pulpal blood flow values did not differ significantly for the 3 groups. In addition, gingival and pulpal blood flow did not change in the nonsurgical control group. Analysis of the postsurgical change from baseline blood flow values indicated a significant increase in pulpal blood flow in the maxillary surgery patients relative to the patients treated with mandibular surgery. However, no significant group difference was found for gingival blood flow.

CONCLUSIONS

This study provides evidence that pulpal blood flow is increased between the first and third week after Le Fort I osteotomy, but it did not find a significant change in gingival blood flow.

Neurosensory recovery after ligation of the descending palatine neurovascular bundle during Le Fort I osteotomy

PURPOSE

The effect of ligating the descending palatine neurovascular bundle (DPNB) on the recovery of palatal sensation has not been clearly established. The purpose of this study was to determine the effect of ligation of the DPNB on the recovery of palatal sensation after Le Fort I osteotomy.

PATIENTS AND METHODS

Using a retrospective study design in a randomized protocol, patients who had undergone Le Fort I osteotomy were assigned to either treatment group 1 (DPNB ligated) or treatment group 2 (DPNB preserved). A third group of control patients (group 3, unoperated) on whom no surgery had been performed served as a baseline for examination of normal palatal sensation. The predictor variables were ligation and preservation of the DPNB. The outcome variables were mean tactile sensation and mean nociception. Other study variables included age, sex, follow-up, surgical movements, and number of segments.

RESULTS

There were 11 patients in group 1, 7 in group 2, and 10 in group 3. For tactile sensation, the mean Von Frey hair size detected was 4.26 +/- 0.37, 4.11 +/- 0.17, and 3.68 +/- 0.24 for groups 1, 2, and 3, respectively. The difference between group 1 and group 2 was not significant (P > .05). The differences between group 1 and group 3 and between group 2 and group 3 were significant (P < .05). For nociception, the mean pressure was 51.09 +/- 21.73, 50.89 +/- 19.19, and 56.25 +/- 19.02 for groups 1, 2, and 3, respectively. The difference between the 3 groups was not significant (P = .8064).

CONCLUSION

The results of this study suggest that recovery of palatal sensation is not adversely affected by ligation of the DPNB.

Periodontal and pulpal condition of the central incisors after midline osteotomy of the maxilla

PURPOSE

The purpose of this study was to evaluate the periodontal and pulpal condition of the central incisors after Le Fort I and midline osteotomies for transverse expansion of the maxilla.

PATIENTS AND METHODS

The series included 12 women and eight men, with an average age at operation of 28.4 years (range, 17 to 48 years). Each patient, examined retrospectively, underwent transverse expansion of the maxilla by combined Le Fort I and midline osteotomies. The minimum follow-up was 12 months (range, 12 to 85 months, with an average of 38 months). The central incisors were tested for percussion sound, mobility, and pulpal response to electric stimulation, and then compared with the lateral incisors. The pocket depths and the height of the alveolar bone were measured, and the root surface was evaluated for resorption on radiographs.

RESULTS

Percussion and mobility tests indicated normal values for all teeth. Four (11%) of the central incisors did not respond to electrical stimulation. There was no difference in pocket depth between the mesial and distal sulci of the central incisors. In one tooth, resorption was detectable on the medial surface of the root. Minor root surface injury was seen in two roots, although these injuries were not progressive. The alveolar bone level of the central incisors was located slightly more superiorly on the mesial than on the distal side.

CONCLUSIONS

Although there may be some minor complications to the periodontal and pulpal tissues after combined Le Fort I and midline osteotomies, the harmful effects seem to be of negligible clinical significance.

Endodontic sequelae of miniplate bone fixation

Various techniques of rigid internal fixation have evolved to achieve skeletal stability during healing. Although the miniplates and screws currently used have many advantages, their placement and presence may present significant difficulties for clinicians subsequently providing treatment. Problems with both endodontic diagnosis and treatment after miniplate fixation are illustrated with three case reports.

Sensory nerve disturbance following Le Fort I osteotomy

This study assessed sensory nerve disturbance after Le Fort I osteotomy using the electric pulp test, pin-prick sensation, fine touch, and cold sensation. After 6 months, 78% of teeth positive preoperatively to an electric pulp tester regained sensitivity. Return of palatal sensation was affected by whether or not the greater palatine nerve (GPN) was divided during surgery. After 6 months, where the GPN was intact, all patients had fine touch sensation (88% at the preoperative level), and all had pin-prick sensation (97% at preoperative level). When the GPN was divided, all patients had fine touch sensation (13% at preoperative level), and all had pin-prick sensation (63% at preoperative level). The differences in the return to preoperative sensation were significant for fine touch (P=0.0001++) and for pin-prick (P-0.03) by chi-square analysis. Sensation returned more quickly and more completely in the two cases where the contralateral GPN was intact. In the buccal mucosa, 95% of patients regained some fine touch sensation after 6 months, but none returned to the preoperative level. Similarly, 85% regained some pin-prick sensation, but none achieved preoperative levels. Cold sensation, pin-prick sensation, and fine touch on the face returned to the preoperative level in all patients by 6 weeks postoperatively.

Pulpal and apical changes secondary to segmental osteotomy in the mandible--an experimental study

Posterior segmental osteotomies were performed on 7 dogs to investigate postoperative changes in the pulpal and periodontal tissue. Osteotomy cuts were made at various distances from the apices of roots. After 3 to 6 months, results were evaluated clinically, radiographically and histopathologically. Clinical and radiographic healing of the osteotomy sites was uneventful. Histological evaluation revealed that when the osteotomy cuts were made at a safe distance (3-5 mm) from the apices of roots, neither important pulpal degeneration nor loss of teeth occurred. Even two of the teeth whose apices were cut off had completely healthy pulpal and periapical tissues. The periodontium in almost all of the cases was also found to be healthy.

A prospective study on changes in the sensibility of the oral mucosa and the mucosa of the upper lip after Le Fort I osteotomy

A prospective study on 21 patients was performed in order to investigate the changes in the sensibility of the oral mucosa and the mucosa of the upper lip after a Le Fort I osteotomy. Patients were followed-up 1 month, 3 months and 6 months postoperatively. The sensibility of the mucosa was tested using electrical sensimetry (Laitinen, 1987). The teeth were tested with carbon dioxide snow (Obwegeser and Steinhäuser, 1963). A picture of the marked hypoaesthetic area was performed and magnified 1:1 if a hypoaesthesia of the cutaneous distribution of the infraorbital nerve was found. The area was measured using a Macintosh II CX computer. It was demonstrated, that after 3 months the infraorbital nerve regained its function completely. The greater palatine nerve and the posterior superior alveolar nerve demonstrated an incomplete recovery of sensory function after 6 months. After 6 months 92.8% of the teeth reacted to carbon dioxide snow. Within the first 6 months postoperatively, no pulpe necrosis was observed. No correlation could be found between the amount of anterior maxillary movement and the degree of hypoaesthesia of the infraorbital nerve. Dentate Le Fort I osteotomies showed a better sensory regeneration of the greater palatine nerve than edentulous Le Fort I osteotomies. After Le Fort I osteotomies in 2 parts, more hypoaesthesia of the greater palatine nerve was observed than after Le Fort I osteotomies in 1 part. After miniplate osteosynthesis, more hypoaesthesia of the posterior superior alveolar nerve was observed than after wire osteosynthesis. The results are discussed and compared with the results found in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulpal response to orthognathic surgery: a long-term radiographic study

The purpose of this study was to determine if the ischemia associated with orthognathic surgery causes long-term pathologic changes in the pulp similar to those documented after traumatic injuries. A total of 93 patients, 21.9 to 63.9 years of age (mean 38.5 years, SD 9.4), consented to participate in a follow-up study ranging from 4.7 to 15.3 years (mean 8.9 years, SD 2.9) after surgery. LeFort I osteotomy was performed on 42 patients and bilateral sagittal split osteotomies on 76 patients. Full-mouth series of periapical radiographs taken at the time of follow-up were compared with pretreatment and posttreatment panoramic radiographs. The development of pulp canal obliteration was observed more often in the maxillae of patients treated with LeFort I osteotomy than in those without (p < 0.001). No difference was seen in the frequency of maxillae with teeth developing radiographic signs of pulp necrosis between patients treated with and without LeFort I osteotomy. However, a higher proportion of the teeth were affected among the patients treated with osteotomy (p < 0.01). The presence of a restoration or caries was a risk factor for the development of necrosis (p < 0.01). Bilateral sagittal split osteotomies had no apparent effect on long-term pathologic pulpal changes. No internal resorption was seen. Only very few teeth were extracted during the follow-up period.

Intra- and early postoperative complications of the Le Fort I osteotomy. A retrospective study on 410 cases

The results of a retrospective study of the complications that occurred in 410 Le Fort I osteotomies performed in the Department of Oral and Maxillofacial Surgery of the Free University Hospital, Amsterdam, the Netherlands, are presented. The complication rate was 9.0%. In the discussion, our results are compared with the literature.--Suggestions are made on how to avoid these complications.

Orthognathic surgery and pulpal blood flow: a pilot study using laser Doppler flowmetry

The purpose of this study was to analyze the effect of Le Fort I osteotomy on pulpal circulation. A laser Doppler flowmeter was used to measure pulpal blood flow of maxillary right and left central incisors and a randomly selected mandibular canine in 14 volunteers prior to surgery and at various intervals during the 6 months following surgery. Custom-made splints allowed accurate and reproducible positioning of the measurement probe. The data showed a significant reduction in vascular supply at the final observation. However, a high variability of individual blood flow patterns was found. In some patients, transient periods of ischemia were observed shortly after surgery. Also, numerous teeth demonstrated hyperemia at later intervals. One patient developed discoloration of a central incisor, and another lost marginal periodontal support around both central incisors. However, in none of the 14 subjects was pulpal blood flow found to be absent following surgery.

Recovery of neurosensory function following orthognathic surgery

The purpose of this study was to prospectively define the recovery of touch discrimination following four commonly performed surgical procedures in 22 consecutive patients with no previous maxillofacial surgery. The surgical groups studied were Le Fort I osteotomy (LEFORT; n = 13), sagittal split ramus osteotomy (SSRO; n = 6), intraoral vertical ramus osteotomy (IVRO; n = 9), and isolated genioplasty (GENIO; n = 5). Neurosensory function was assessed by three different testing modalities which included static light touch (SLT), moving touch discrimination (MTD), and two-point discrimination (TPD). Cutaneous sensation of the lower lip and chin were examined for the mandibular procedures, whereas the infraorbital and upper lip regions were evaluated following maxillary surgery. Immediately following surgery, each group varied in both the incidence and magnitude of neurosensory deficits (NSD). The SSRO group had the highest percentage of sites with immediate postsurgical NSD to both SLT (72%) and MTD (67%), followed by the LEFORT (SLT = 50%, MDT = 58%), GENIO (SLT = 27%, MTD = 6%), and IVRO groups (SLT = 11%, MTD = 18%), respectively. Each group also varied in the severity of the initial postoperative deficit as measured by SLT, with the SSRO group showing the greatest deficit followed by the LEFORT, GENIO, and IVRO groups. During the 6-month recovery period each group approached preoperative levels of sensation at a different rate. The LEFORT group recovered most rapidly, with few anatomic sites showing NSD (SLT = 20%, MTD = 5%) at the 1-month postoperative examination, and the majority of the group (96%) returned to preoperative sensation by 3 months following surgery. The SSRO group recovered more slowly, with approximately half of the group demonstrating a deficit (SLT = 50%, MTD = 59%) at 1 month, which diminished to about one fourth of the sites (SLT = 25%, MTD = 5%) by 3 months. Most of the SSRO group (90%) exhibited no residual deficit 6 months following surgery. The IVRO group had few sites with immediate NSD (SLT = 11%, MTD = 15%). In none of the surgical groups was a statistically significant correlation found between the severity of the initial NSD and length of time to complete recovery.

Tooth pulp changes following Le Fort I maxillary osteotomy in a primate model

Le Fort I maxillary 'down-fracture' osteotomy with 8 mm advancement was performed in 15 adult rhesus monkeys. Forty-five tooth pulps were examined histologically at intervals from 0 to 24 weeks after surgery. Cell degeneration occurred in 31% of pulps examined, necrosis in 16% of pulps and osteo-dentine was found in 7% of pulps. Almost half of the teeth examined (47%) showed marked cellular changes, more frequently found in posterior teeth. Other features noted were inflammation (13%) and reactive dentine in pulps (24%). Axons degenerated initially but recovered by 24 weeks. It is concluded that Le Fort I maxillary osteotomy caused pulpal disturbances in an animal model and the extent to which this occurs in patients needs to be carefully monitored.

Pulp canal obliteration after Le Fort I osteotomy

A longitudinal study of 51 patients was carried out to determine the frequency of pulp canal obliteration (PCO) after Le Fort I osteotomy for the correction of dentofacial anomalies and to analyse pre- and peroperative factors influencing the development of PCO. PCO developed in 14 (2.3%) of 617 maxillary teeth followed for an average period of 28 months (range 11-59). The highest frequency of PCO was demonstrated in canines (6.0%) and premolars (4.4%). Total PCO was present in 9 teeth and partial PCO in 5 teeth. PCO was more frequent among teeth adjacent to a vertical interdental osteotomy than in teeth with no relation to a vertical osteotomy (p less than 0.0001). Change in blood supply after the operation was suggested to be responsible for PCO, although it might have been effected by the combined surgical and orthodontic treatment. Long-term follow-up, including periapical radiographs, of teeth with PCO is suggested, as pulp necrosis may develop many years after surgery.

The contribution of the nasopalatine nerve to sensation of the hard palate

This study investigates which areas of the hard palate are innervated by the nasopalatine nerve and determines whether division of this nerve results in a detectable alteration in sensation. In the first part of this study the area of the hard palate from which sharp and blunt sensation could be evoked was investigated in 20 subjects after anaesthetising both anterior (formerly greater) palatine nerves. Sensation remained in the region of the incisive papilla and gingival margin of the central incisors in all patients and, in some, extended as far back as the first premolars. In the second part of the study, sharp and blunt sensation of the hard palate were tested before and after incisive bundle division. No significant alteration in sensation was found in any of the 20 patients tested.

Pulp sensibility and pulp necrosis after Le Fort I osteotomy

A longitudinal study comprising 617 teeth in 51 patients was carried out to determine the frequency of pulp necrosis and loss of pulpal sensibility after Le Fort I osteotomy. A negative pulpal sensibility was found in 39 (6%) teeth after an average follow-up period of 28 months, range 11-59 months. Development of pulp necrosis, determined by pulp testing and periapical radiolucency, was only demonstrated in 3 (0.5%) teeth. The extent of horizontal or vertical displacement of the maxilla had no influence on pulpal sensibility. Teeth adjacent to a vertical interdental osteotomy showed a significantly higher frequency of negative reactions compared to the group without an interdental osteotomy (p = 0.002). The canines demonstrated a significantly greater number of teeth with a negative sensibility reaction compared to the other tooth types. A close relationship between the apex of the canines and a wire osteosynthesis was demonstrated to have significant importance for pulpal sensibility.