Minor Complications Arising in Alveolar Distraction Osteogenesis

J Oral Maxillofac Surg 

60:496-501, 2002 

Minor Complications Arising in Alveolar 

Distraction Osteogenesis 

Abel Garcia Garcia, MD, PhD,* Manuel Somoza Martin, DDS,† 

Pilar Gandara Vila, DDS,‡ and Jacobo Lopez Maceiras, DDS§ 

Purpose: This study evaluates complications that arise during mandibular alveolar distraction osteogenesis 

and suggests treatments. 

Methods: We monitored complications that arose during alveolar distraction osteogenesis in 5 patients 

who underwent a total of 7 distractions, in all cases using an intraosseous distractor (Lead System, 

Leibinger, Germany). We report our responses to each type of complication. 

Results: All 7 distractions were followed by the placement of 2 implants. The restoration was ideal in 

4 of the 7 cases and functional but not ideal in the remaining 3. In all 7 distractions, we observed 

complications, although many were minor complications readily avoided by the use of appropriate 

technique. The complications were, first, intraoperative complications, namely 1) fracture of the 

transport segment (1 of 7 cases; Response: appropriate preventative measures), 2) difficulties in finishing 

the osteotomy on the lingual side (7 of 7 cases; Response: use of fine chisels made from cement spatulas), 

and 3) excessive length of the threaded rod (1 of 7 cases; Response: cut the rod). Second, complications 

arose during distraction: 1) incorrect direction of distraction (2 of 7 cases; no corrective measures 

necessary in the present cases), 2) perforation of the mucosa by the transport segment (2 of 7 cases; 

response: smooth the crest of the segment with a bone rongeur), and 3) suture dehiscence (1 of 7 cases; 

no significant implications). Third, there were postdistraction complications, namely bone formation 

defects (4 of 7 cases; response: guided bone regeneration). 

Conclusion: A number of complications may arise during alveolar distraction osteogenesis. Most of 

these complications can be considered minor and are readily avoided or resolved by the use of 

appropriate procedures. 

© 2002 American Association of Oral and Maxillofacial Surgeons 

J Oral Maxillofac Surg 60:496-501, 2002 

Alveolar distraction osteogenesis is a recently introduced 

surgical technique that is rapidly gaining widespread 

acceptance. A number of distraction devices 

are commercially available. In general, these can be 

*Head of Section, Department of Maxillofacial Surgery, 

Complejo Hospitalario Universitario de Santiago and Professor of 

Maxillofacial Surgery, University of Santiago de Compostela, Santiago 

de Compostela, Spain. 

†Assistant Professor, Oral Surgery Unit, School of Dentistry, University 

of Santiago de Compostela, Santiago de Compostela, Spain. 

‡Assistant Professor, Oral Surgery Unit, School of Dentistry, University 

of Santiago de Compostela, Santiago de Compostela, Spain. 

§Postgraduate Student, Oral Surgery Unit, School of Dentistry, 

University of Santiago de Compostela, Santiago de Compostela, 

Spain. 

Address correspondence and reprint requests to Dr Garcia: Facultad 

de Odontologia, Entrerrios s/n, Santiago de Compostela, 

Spain; e-mail: ciabelgg@usc.es 

© 2002 American Association of Oral and Maxillofacial Surgeons 

0278-2391/02/6005-0004$35.00/0 

doi:10.1053/joms.2002.31844 

496 

classified as juxtaosseous or intraosseous. Juxtaosseous 

distractors (eg, Distractor Track; KLS/Martin, Tuttlingen, 

Germany) are placed over the buccal surface 

of the jaw, whereas intraosseous distractors (eg, Lead 

System, Leibinger, Kalamazoo, MI; and DIS-SIS Distractionimplant; 

SIS Systems Trade GmbH, Klagenfurt, 

Austria) are placed through the transport segment in 

the direction of distraction. 

We used Lead System distractors because of their 

simplicity, their small size, and their low cost in 

comparison with juxtaosseous distractors. Lead System 

distractors are intraosseous distractors that 

consist of a threaded rod, a transport plate, and a 

base plate: the threaded rod transverses the transport 

segment from the alveolar margin to the distraction 

gap, where it screws into the transport 

plate, which in turn is screwed to the transport 

segment. Also in the gap, the tip of the threaded 

rod rests against the base plate, which is screwed 

into the basal bone. Turning the threaded rod separates 

the transport plate from the base plate, increasing 

the size of the gap. 1

GARCIA ET AL 497 

Here we report a study of complications arising in 

5 patients during osteotomy and subsequent distraction 

with a Lead System distractor, and we propose 

treatments for each type of complication. 

Materials and Methods 

SAMPLE 

We studied 5 patients who had undergone a total of 

7 mandibular alveolar distractions. In all cases, the 

distraction was performed using a Lead System distractor. 

Six of the 7 distractions were performed in 

the posterior mandible, and 1 was performed in the 

incisive-canine region. 

SURGICAL TECHNIQUE 

All patients were treated while under local anesthesia. 

A crestal incision was made along the alveolar 

ridge, and a vestibular mucoperiosteal flap was raised, 

maintaining the attachment of the lingual mucoperiosteum 

to the transport segment. The transport segment 

was cut to an inverted trapezoidal shape, so as 

not to interfere with mobility during distraction. Osteotomy 

was performed with rotary instruments (sidecutting 

burrs, discs, and reciprocating saws) and chisels. 

The transport segment was totally mobilized 

although remained attached to the lingual mucoperiosteum. 

The distractor (ie, threaded rod, transport 

plate, and base plate) was assembled and positioned 

according to the procedure of Chin1 (Fig 1). 

Once the distractor had been positioned, and without 

suturing the mucoperiosteal flap, the transport 

segment was immediately raised (ie, within the same 

surgical session) to a height of 5 mm to confirm 

adequate mobility and appropriate direction of movement 

and absence of interference between the transport 

segment and the basal bone. The transport segment 

was then returned to its original position. 

Distraction was commenced 7 days later at a rate of 

0.5 mm every 12 hours for 5 days. After 12 weeks, the 

distractor was removed, and the implants were 

placed. At 14 weeks after implant placement, the 

prosthetic restoration was commenced and subjected 

to load. Restorations were subsequently classified as 

ideal, functional but not ideal, or nonfunctional. 

The complications that arose are considered in 3 

groups: intraoperative complications, complications 

arising during distraction, and postdistraction complications. 

Results 

In all cases, bone formed in the regeneration chamber, 

and the transport segment was stable. Likewise, 

in all cases, 2 implants were subsequently successfully 

FIGURE 1. Photograph showing placement of the Lead System distractor. 

A crestal incision is made along the alveolar ridge, and a 

vestibular mucoperiosteal flap is raised, maintaining the attachment of 

the lingual mucoperiosteum (B) to the transport segment (A) (C, basal 

bone). The distractor is then placed as shown: D, threaded rod; E, 

transport plate; and F, base plate. 

placed in the distracted region (8 ITI � 4.1 mm, 12.0 

mm PLUS; Straumann, Waldenburg, Switzerland and 4 

Frialoc D4/L13; Friadent, Mannheim, Germany). In all 

cases, a prosthetic restoration was subsequently performed. 

The restoration was ideal in 4 of the 7 cases 

and functional but not ideal in the remaining 3 cases. 

Complications are summarized in Table 1. 

INTRAOPERATIVE COMPLICATIONS 

Fracture of the Transport Segment 

This type of complication occurred in 1 case, due 

to an attempt to free the transport segment using a 

chisel. As a result, a small fragment of cortical bone 

was lost. Subsequent bone formation in the region of 

the lost fragment was deficient. 

Difficulties in Completing the Osteotomy on the 

Lingual Side 

In all 7 cases, difficulties were encountered in completing 

the osteotomy on the lingual side, which we 

had to access from the labial vestibular side. To do 

this, we constructed fine chisels from cement spatulas 

(Fig 2), which we carefully introduced from the vestibular 

side, checking their exit from the lingual side 

with a finger so as to avoid damage to the lingual 

mucoperiosteum or the floor of the mouth. 

Excessive Length of the Threaded Rod 

In 1 case, the threaded rod may have interfered 

with occlusion. This complication can be predicted

498 MINOR COMPLICATIONS AND ALVEOLAR DISTRACTION 

Table 1. COMPLICATIONS OF THE ALVEOLAR DISTRACTION 

Patient 

No. Distraction Location 

1 Left posterior 

mandibular region 



3 Incisive-canine 




Right posterior 




Right posterior 


with the aid of articulator-mounted casts and is readily 

resolved by cutting the rod to the appropriate length 

before placement. 

COMPLICATIONS DURING DISTRACTION 

Incorrect Direction of Distraction 

This complication occurred twice, due to lingual 

deviation of the threaded rod. As a consequence, 

excessive bone formed in the lingual direction. In 

both cases, however, sufficient bone was obtained to 

fit 12-mm implants. 

Perforation of the Mucosa by the Transport 

Segment 

This complication occurred twice, due to the sharp 

edges of the transport segment. In 1 case, a lingual 

Complications Implants 

Intraoperative During Distraction Postdistraction Placed Restoration 

Excessive length of the 

threaded rod 

Fracture of the transport 

segment 

Difficulties in completing 

the osteotomy on the 

lingual side 



















FIGURE 2. Osteotomes constructed from cement spatulas. 

Incorrect 

direction of 

distraction 

Perforation of the 

mucosa by the 

transport 

segment 

Suture 

dehiscence 

Perforation of the 

mucosa by the 

transport 

segment 

Incorrect 

direction of 

distraction 

Bone formation 

defects 


defect 


defect 


defect 

ulcer arose. Treatment involves elimination of the 

sharp edge with use of a burr or a rongeur. In both 

cases, the mucosa grew over the bone, without any 

need to interrupt the distraction. 

Suture Dehiscence 

This occurred in 1 case, leading to some exposure 

of the transport segment. There was no need to interrupt 

distraction, and the mucosa subsequently 

grew completely over the bone. 

POSTDISTRACTION COMPLICATIONS 

2 ITI Functional 

but not 

ideal 

2 ITI Ideal 

2 ITI Ideal 

2 ITI Ideal 

2 ITI Ideal 

2 Frialoc Functional 

but not 

ideal 

2 Frialoc Functional 

but not 

ideal 

Bone Formation Defects 

Complications of this type arose in 4 cases. In 3 

cases, bone formation was not uniform, giving rise to 

bone formation defects. In all cases, these defects led 

to incomplete coverage of the implant (dehiscence or 

fenestration). In 1 case (noted in section on fracture 

of the transport segment), the defect was a dehiscence 

defect due to loss of a fragment of the transport 

segment during osteotomy. In the other 2 cases, the 

defects were fenestration defects. Treatment was 

bone regeneration using Bio-Oss and Bio-Gide reabsorbable 

membranes (Geistlich Pharma AG, Wolhusen, 

Switzerland).


Discussion 

Since the 19th century, there have been numerous 

attempts to develop techniques to extend the long 

bones. 2,3 Distraction osteogenesis of the long bones 

was pioneered by Ilizarov. 4-6 More recently, distraction 

techniques have been applied to the facial bones 

and soft tissues, 7-13 including use in the treatment of 

inadequate height of the alveolar ridge. 14-19 

Alveolar distraction osteogenesis promises to have 

very useful applications in the field of implantology, 

particularly in cases of mandibular alveolar hypoplasia. 

In such cases, the lack of sufficient bone height 

between the alveolar canal and the alveolar rim means 

that the implant must be short; at the same time, the 

reduced height of the rim means that the crown must 

be long. By increasing the height of the alveolar rim, 

alveolar distraction osteogenesis overcomes both 

problems. 

An understanding of the potential complications of 

a given surgical technique, and of appropriate treatments, 

is fundamental for correct implementation of 

that technique. In the present study, we therefore 

evaluated complications arising in 7 alveolar distractions, 

all performed with Lead System distractors (Table 

2). 

Fracture of the transport segment during osteotomy 

is a complication that can be avoided only by 

preventative measures. The thickness of the transport 

segment should be sufficient to withstand the osteotomy 

maneuvers. Care should be taken in manipulation, 

and no attempt should be made to move the 

segment until the osteotomy is complete. 

With rotary instruments, it is easy to perform the 

osteotomy on the vestibular side, but the osteotomy 

on the lingual side is more difficult. To overcome this 

complication, we designed and constructed chisels 

from cement spatulas, allowing us to complete the 

osteotomy of the lingual cortex while respecting the 

integrity of the mucoperiosteum. 

Excessive length of the threaded rod, hindering 

proper occlusion, is a significant problem, because 

the distractor must remain in the patient’s mouth for 

at least 14 weeks. However, presurgical planning 

with articulator-mounted casts should enable the 

problem to be predicted. In the case of Lead System 

distractors, the problem is readily solved, because the 

threaded rod can be cut without affecting its function. 

Inappropriate direction of distraction may be due 

to any of several factors. Generally, the distractor will 

tend to lean to the lingual side. The hole drilled for 

insertion of the threaded rod may be angled incorrectly. 

Either the base plate or the transport plate may 

not fit correctly. The force exerted by the lingual 

periosteum attached to the transport segment may 

lead to inappropriate direction of distraction if not 

taken into account (Fig 3). To solve this complication, 

Table 2. TREATMENT AND CONSEQUENCES OF THE COMPLICATIONS OF ALVEOLAR DISTRACTION 

Complications Treatment Consequences 

Intraoperative 

Fracture of the transport segment Appropriate preventative measures Absence of bone formation 

Difficulties in completing the osteotomy on 

the lingual side 

Use of appropriate instruments Extended surgery time 

Excessive length of the threaded rod 

During distraction 

Cut the rod If not corrected, interference 

with occlusion 

Incorrect direction of distraction Care in positioning the distractor at the Bone formation in the wrong 

correct angle 

Take into account the effect of the lingual 

mucoperiosteum 

Use of orthodontic devices (Chin 

direction 

1 ) 

Perforation of the mucosa by the transport Smooth the extremes of the segment with Lingual ulcer 

segment 

a burr or rongeur 

Suture dehiscence 

Breakage or loss of the distractor (Millesi- 

Schobel et al, 

No action usually required; closure by 

second intention 

No sequelae observed 

21 Gaggl et al22 ) 

Post distraction 

Bone formation defects Guided bone regeneration 

Application of a titanium membrane during 

the osteotomy (Klug et al 

Gaps in the bone around the 

implant 

20 Other 

Dysesthesia of the mental nerve (Klug et 

al, 

) 

20 Gaggl et al, 22 Nocini et al23 )

500 MINOR COMPLICATIONS AND ALVEOLAR DISTRACTION 

FIGURE 3. Diagram showing the tension exerted by the lingual 

mucoperiosteum (C) on the transport segment, leading if not corrected 

to distraction direction (B) as opposed to the desired distraction direction 

(A). 

Chin 1 proposed the use of an orthodontic appliance 

to guide the threaded rod. However, this requires 

that the edentulous space should have teeth at both 

extremes, which was not the case in either of the 

subjects who had this complication in the present 

study. When the distractor is assembled and positioned, 

it is thus important to bear in mind the forces 

exerted by the lingual mucoperiosteum attached to 

the segment and to angle the threaded rod slightly 

outward to compensate for this force during distraction. 

Perforation of the mucosa by the sharp edges of the 

transport segment is typically observed as the distraction 

proceeds. Elimination of the sharp edges allows 

rapid growth of the mucosa over the bone, in contrast 

to the situation expected with a free bone graft. This 

complication does not require interruption of the 

distraction procedure. 

Suture dehiscence was observed in a single case 

and did not constitute a problem; indeed, it was not 

even necessary to interrupt the distraction procedure. 

The transport segment is vascularized, so epithelium 

grows normally over it. Normal epithelium growth 

does not occur with free bone grafts. This complication 

may lead to loss of the graft. 

Bone formation defects were observed in 3 cases. 

In 1 case, the defect was a dehiscence defect due to 

the loss of a fragment of bone from the transport 

segment during the osteotomy. In the other 2 cases 

(both fenestration defects), there was no evident explanation 

for the defect observed. All of these defects 

were successfully treated with Bio-Oss covered with a 

Bio-Gide membrane. Klug et al 20 proposed that complications 

of this type can be avoided by fitting a 

titanium membrane over the defect immediately after 

osteotomy, to avoid invasion by connective tissue. 

However, this technique may give rise to further complications, 

such as exposure of the titanium membrane. 

In no case did we observe complications that involved 

the inferior dental nerve, which are to be 

expected in particular during osteotomy. Such complications 

are especially likely if the mandible is 

highly atrophic. 

Millesi-Schobel et al 21 reported a case of fracture 

of the distractor during mandibular alveolar distraction 

in a patient in whom a juxtaosseous-type distractor 

was used. In reports presented at the XVth 

Congress of the European Association for Cranio- 

Maxillofacial Surgery in Edinburgh in September 5 

through 9, 2000, Klug et al, 20 Gaggl et al, 22 and 

Nocini et al, 23 mention other complications, such 

as dysesthesia of the mental nerve and mandibular 

fracture. In addition, Gaggl et al, 22 reported loss 

of the implant in a patient in whom a DIS-SIS distraction 

implant (SIS Systems Trade GmbH) was 

used. We have not observed any of these complications. 

In view of our results and our review of the 

literature, it may appear that complications are unacceptably 

frequent in this procedure. However, it 

should be stressed that the complications that arose 

can all be considered minor and in all cases had 

simple solutions; in no case did the complications 

cause the technique to fail or reduce the rate of 

distraction. 

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Minor Complications Arising in Alveolar Distraction Osteogenesis

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