Fibrous Union Research Articles

Returning athletes with severe low back pain and spondylolysis to original sporting activities with conservative treatment

The purpose of this study was to clarify the efficacy of conservative treatment in athletes with severe low back pain and spondylolysis, especially focusing on returning to original sporting activities. One hundred and four athletes (96 males and eight females), who consulted our sports medicine clinic during the 11-year period between September 1991 and October 2002 because of low back pain with an apparent defect of the pars interarticularis on plain radiographs, were subjected to conservative treatment. The mean age of the patients was 20.7 years. Of all the patients, 40 (38.5%) discontinued sporting activities due to severe low back pain, and were conservatively treated with activity restriction and antilordotic lumbosacral bracing, aimed at relieving low back pain by achieving stability of the fracture partly associated with fibrous union. After their low back pain was markedly reduced, the brace was removed and then individual training to return to the original sporting activities was started. Thirty-five patients (87.5%) could return to their original sporting activities in an average of 5.4 months (range: 1.0-11.5 months) after the onset of treatment, and could continue the activities for at least 6 months despite non-bony union. These results suggest that the outcome of conservative treatment with activity restriction and bracing appears to be satisfactory in controlling symptoms and returning to original sporting activities. Randomized controlled trials or comparative follow-up studies are needed to confirm our results.

Cervical spine fusion with bioabsorbable cages.

Although it improves rates of fusion in surgical arthrodesis, conventional spinal instrumentation is associated with several risks, including hardware extrusion that injures adjacent anatomical structures, and disuse osteopenia as a result of stress shielding. The long-term effects of indwelling spinal instrumentation, although incompletely documented, may be detrimental. One way to avoid such problems would be to use bioabsorbable implantation devices. In this pilot study, performed in 1998 and 1999, the authors evaluated the use of a bioabsorbable interbody fusion device in a goat cervical spine model. Forty-two goats underwent two-level anterior cervical discectomy and fusion: eight received iliac crest autograft; 16 received a cage implant composed of 70:30 poly(L-lactide-co-D,L-lactide)/polyglycolic acid (70:30 PLDLLA/PGA) filled with either autograft or recombinant human bone morphogenetic protein-2 (rhBMP-2); and 18 received a cage implant composed of 85:15 PLDLLA/PGA filled with either autograft or rhBMP-2. Animals were killed at 3, 6, and 12 months postsurgery, and their cervical spines were evaluated histologically, radiographically, and physically for fusion. A primarily fibrous union was demonstrated in all animals killed at 3 months. At 6 months, bone trabeculae had become more prominent and the fibrous response less so in all cohorts. This occurred most frequently in the animals that underwent fusion with the 70:30 PLDLLA/PGA cages filled with rhBMP-2, in which 63% attained a histologically confirmed union that contained quantitatively more bone and less fibrous tissue than in the other cohorts; 63% of the unions in the aforementioned cohort were graded quantitatively as being stable. In this study the authors have established that the 85:15 PLDLLA/PGA cages are absorbed too quickly to be functionally useful in this model. The 70:30 PLDLLA/PGA cages worked as well as tricortical autograft when filled with cancellous autograft, and better when filled with rhBMP-2. At 6- and 12-month follow-up review, the 70:30 PLDLLA/PGA cages had not yet begun to be absorbed. There was little if any inflammatory response to these cages at 6 months. Future studies should include biomechanical and microradiographic testing, and a longer follow-up period is necessary in this model to determine when the 70:30 PLDLLA/PGA cages are absorbed.

The Classic: Revision of Aseptic Loose Total Hip Arthroplasties

The Classic: Revision of Aseptic Loose Total Hip Arthroplasties

Effect of distraction osteogenesis on the severely hypoplastic mandible and inferior alveolar nerve function

Purpose The purpose of this study was to examine the effect of distraction osteogenesis surgery on the inferior alveolar nerve (IAN) and on the stability of the occlusion in patients undergoing mandibular osteotomy and advancement for correction of severe retrognathia. Materials and methods Five patients (4 women and 1 man) underwent vertical posterior body osteotomy or bilateral sagittal split ramus osteotomy with the application of a distraction device for advancement of the mandible of 10 to 14 mm. After a period of latency, each mandible was advanced 1 mm per day until the patient achieved a Class I occlusion. Distraction devices were removed after a suitable period of consolidation (4 to 11 months). IAN sensory function was evaluated by 2-point discrimination, response to painful stimulus, and moving brush stroke identification. Testing of the IAN was performed on all patients at 7 different time intervals: preoperative (T0), postsurgery and predistraction (T1), within 7 days after the end of distraction (T2), 3 months after T2 (T3), 6 months after T2 (T4), 9 months after T2 (T5), and 1 year after T2 (T6). The same surgeon performed all IAN testing. Results There were no instances of malunion or fibrous union. At the 1-year follow-up, all 5 patients showed no relapse of their advancement as assessed by their maintenance of a Class I occlusion. Radiographic analysis was not done to discern skeletal versus dental stability. All 10 IANs were intact after the initial surgery. As time progressed, all 10 nerves showed improvement of function as measured by 2-point discrimination, response to painful stimulus, and moving brush stroke identification. At 1 year postsurgery, all 10 nerves showed function consistent with or very near presurgery levels. Conclusion Stable mandibular advancements of 10 mm and greater can be successfully accomplished by distraction osteogenesis without producing significant damage to the IAN.

Arthrodesis for chronic static scapholunate dissociation: a prospective study in 12 patients.

Twelve patients had limited arthrodesis between the scaphoid and the lunate for chronic static scapholunate dissociation using internal plate osteosynthesis. The median time between the injury and surgery was 50 months (range 9-180). They were followed up for a year postoperatively. Preoperative symptoms were pain, functional impairment, and restricted movement. During operation the scapholunate interosseous ligament was completely torn and the scaphoid malrotated in all patients. The range of motion was measured preoperatively and postoperatively, and the unaffected side used for control. For all patients except one postoperative extension, flexion, and radial deviation had considerably decreased. However, supination increased in seven of 12 patients postoperatively and so did pronation in seven of 12 patients. One patient (case 12) had an improved range of motion postoperatively in all directions. The mean grip strength was 76% of the unaffected side preoperatively, and has increased to 85% postoperatively. We found that bone healing was rare and most arthrodeses healed by a fibrous union. We found no correlation with preoperative arthrosis and clinical outcome. One patient had retired from work before operation because of back pain and one because of age. Two patients had taken early retirement because of wrist pain, and one patient was still on sick-leave at the follow-up a year postoperatively. Five patients returned to full-time work and two patients to part-time work. Four patients were on long-term sick-leave preoperatively and three of them returned to their previous occupations. Analysis of the patients' subjective outcome (including pain and functional scores) showed overall satisfaction, and objective data show that scapholunate arthrodesis for chronic static scapholunate dissociation provides substantial improvement over the preoperative condition.

INTERCALARY NON-VASCULARISED TOE PHALANX TRANSPLANTATION FOR SHORT FINGER-TYPE SYMBRACHYDACTYLY

A two-year-old boy with short finger-type symbrachydactyly involving the index, middle, and ring fingers was treated with intercalary nonvascularised toe phalanx transplantation into the middle finger to obtain stability of the middle finger before syndactyly release. He underwent syndactyly release one year after the transplantation. Two years after the transplantation, the clinical result was satisfactory, although X-ray showed fibrous union between the transplanted phalanx and the host phalanx. Intercalary nonvascularised toe phalanx transplantation is one of the way of stabilising a finger after syndactyly release.

The resistance of maxillofacial reconstruction plates to biofilm formation in vitro

Bacterial biofilms, bacteria surrounded by a protective glycocalyx, have been demonstrated on bioimplants placed within and outside of the head and neck region. The presence of the biofilm often makes decontamination of an infected implant impossible, requiring removal of the implant. Infections attributable to biofilm formation within the facial skeleton after reconstruction with implants may result in delayed union, fibrous union, malunion, nonunion, and malocclusion. These complications often require removal of the implant and secondary surgery. Although the incidence of infections necessitating implant removal is relatively low, the increased numbers of implants being placed make this a growing problem. Previous work in the authors laboratory has demonstrated a resistance to biofilm formation on different types of pressure-equalizing tubes. The hypothesis evaluated in the study is that such resistance to biofilm formation is due to the inability of bacteria to adhere to the tubes because of the material's smoothness or surface charge. A controlled observational study. Scanning electron microscopy was used to evaluate the formation of biofilms in vitro for a common strain of Staphylococcus aureus on four implantable materials. The implantable materials included titanium and polylactide resorbable plates. Consistent with the authors' prior findings, they were able to produce bacterial biofilm reliably on a silicone pressure equalizing tube but were unable to demonstrate biofilm formation on the titanium or resorbable implants. The absence of biofilm formation on these implants can best be explained by the surface charge or polarity properties of these materials. These findings are consistent with the relatively low incidence of infections among patients receiving these implants in maxillofacial applications.

Development of a porous poly(L‐lactic acid)/hydroxyapatite/collagen scaffold as a BMP delivery system and its use in healing canine segmental bone defect

A hydroxyapatite/collagen (HAC) composite was produced to mimic the natural extracellular matrix of bone, with the collagen serving as a template for apatite formation. A three-dimensional highly porous scaffold was developed by mixing HAC with poly(L-lactic acid) (PLA) using a thermally induced phase separation technique. Naturally derived bovine bone morphogenetic protein (bBMP) was incorporated into the porous HAC-PLA scaffolds, and the composite then was implanted in diaphyseal defects (2 cm in radius) of adult beagle dogs. Controls were implanted with scaffolds without BMP. The dogs were sacrificed at 6 months, at which time biocompatibility, biodegradability, and osteoinduction were evaluated by histologic and radiologic examination and by bone mineral density (BMD) measurements. All defects healed after treatment with BMP combined with HAC-PLA, and BMD at the site of the defect was higher than the BMD of the intact radius. Fibrous union developed in the control group animals. Histologic observation indicated that the presence of BMP not only promoted osteogenesis but that it also accelerated degradation of the biomaterials. Optimized design parameters of a three-dimensional porous biomaterial would give full scope to the role of BMP as an osteoinductive growth factor.

High prevalence of tarsal coalitions and tarsal joint variants in a recent cadaver sample and its possible significance.

Tarsal coalitions (TC) are defined as fibrous (beyond normal ligaments), cartilaginous, or osseous unions of at least two tarsal bones. Most of the clinical studies report the prevalence of TC as <1%, but they disregard the asymptomatic coalitions. Because TC have been associated with pathologic conditions, including degenerative arthritic changes, knowledge of their prevalence has clinical importance. The aim of our study was to establish the prevalence of TC and tarsal joint variants. A total of 114 feet from 62 cadavers (average age = 78 years) without obvious foot pathologies were dissected at the Department of Anatomical Sciences, The University of Adelaide. Ten non-osseous TC in eight subjects were identified: two talocalcaneal and eight calcaneonavicular (occurred twice bilaterally). Variant calcaneonavicular and cuboideonavicular joints were found in 8% and 31% of feet, respectively. Other joint variants included a variable number of talocalcaneal joint surfaces and sesamoid bones. No secondary TC (due to trauma, infections, or neoplasm) were found. Our study demonstrated that the overall prevalence of TC is higher (13%) than previously thought; tarsal joint variations (39%) and sesamoid bones (42%) were common as well. The supposed secular increase in the prevalence of TC as well as the high number of anatomical variants could reflect a short-term response to altered life-style or a microevolutionary trend due to relaxed selection.

Scapholunate fusion in chronic symptomatic scapholunate instability

Since 1989 scapholunate fusion has been performed on 13 patients with chronic scapholunate instability causing debilitating symptoms. These cases were reviewed at a mean 93 (range, 60–132) months after surgery. Establishing whether bony fusion had been achieved proved extremely difficult even after CT scanning, but fusion was unequivocally achieved in four cases. Ten patients were subjectively satisfied with their treatment. Two patients who had no symptomatic improvement subsequently underwent total wrist arthrodesis. A method of fusing the scaphoid and lunate is described, though we accept that a firm fibrous union may be all that is achieved in most patients. However, this appears sufficient to restore stability with a high patient satisfaction.

Operative treatment of flatfoot with talocalcaneal coalition.

Rigid flatfoot or peroneal spastic flatfoot often is associated with a congenital fibrous, cartilaginous, or osseous union of two tarsal bones or more, potentially causing great difficulties in its treatment. Since 1996, 12 patients (14 feet) with painful flatfoot and restricted motion of the hindfoot attributable to talocalcaneal coalition, were treated by resection of the coalition and subtalar arthroereisis by a bioreabsorbable implant. The results were evaluated by the ankle hindfoot clinical rating system of the American Orthopaedic Foot and Ankle Society. These clinical results also were evaluated statistically. Radiographs and computed tomography scans were taken preoperatively and postoperatively. Eight (57.1% of patients) had excellent results, three (21.4% of patients) had good results, and three (21.4% of patients) had fair results. No poor results, or subjective or objective complications were reported. On the basis of these early results, arthroereisis by implanting a bioreabsorbable device after removal of the tarsal coalition, seems to be an effective procedure for the treatment of symptomatic flatfoot associated with talocalcaneal coalitions: correcting the relationship between talus and calcaneus, restoring the alignment of the hindfoot, and reducing pain.

Non-rigid immobilisation of odontoid fractures.

Despite various reports on the management of odontoid fractures, there is no consensus on the subject, and the appropriate treatment still remains controversial. While untreated fractures or fractures treated only with a cervical orthosis seem to have the highest rate of non-union, the need for rigid external stabilisation has never been substantiated. In a retrospective analysis we reviewed 26 patients with acute type II and III fractures of the odontoid, treated with a cervical orthosis only. Study inclusion was limited to fractures that had a fracture gap of less than 2 mm, an initial antero-posterior displacement of less than 5 mm and angulation of less than 11 degrees, less than 2 mm displacement on lateral flexion/extension views, and were without neurological deficits. These fractures were defined as stable. There were 19 (73.1%) type II and 7 (26.9%) type III fractures; in 10 (38.5%) of these fractures the odontoid was displaced and/or angulated. The overall complication rate was 11.4% ( n=3). One patient suffered from pulmonary embolism, in two patients (7.7%) with initially minimally displaced fractures, secondary internal stabilisation had to be performed because of persistent instability. In 20 (77%) of the remaining fractures healing was uneventful. In 4 nondisplaced fractures (15%) fibrous union was documented. Three of these patients were over 65 years old. The overall fusion rate was 73.7% for type II and 85.7% for type III fractures. At follow-up 39% of the patients were free of symptoms; however, the clinical outcome did not correlate with the radiological findings. According to our findings, stable type II and type III fractures of the odontoid can be successfully treated with non-rigid immobilisation, even if they are displaced. A thorough assessment of the stability of the odontoid with lateral flexion/extension views or dynamic fluoroscopy is recommended to evaluate the appropriate treatment. Non-rigid immobilisation may be an option in selected cases with stable injuries.

Fixation of mandibular fractures with 2.0-mm miniplates: Review of 191 cases

Purpose: Our goal was to study the use of 2.0-mm miniplates for the fixation of mandibular fractures. Patients and Methods: Records of 191 patients who experienced a total of 280 mandibular fractures that were treated with 2.0-mm miniplates were reviewed. One hundred twelve of those patients, presenting 160 fractures, who attended a late follow-up were also clinically evaluated. Miniplates were used in the same positions described by AO/ASIF. No intermaxillary fixation was used. All patients included had a minimum follow-up of 6 months. Demographic data, procedures, postoperative results, and complications were analyzed. Results: Mandibular fractures occurred mainly in males (mean age, 30.3 years). Mean follow-up was 21.92 months. The main etiology was motor vehicle accident. The most common fracture was the angle fracture (28.21%). Twenty-two fractures developed infection, for an overall incidence of 7.85%. When only angle fractures are considered, that incidence is increased to 18.98%. Although only 1 patient (0.89%) described inferior alveolar nerve paresthesia, objective testing revealed sensitivity alterations in 31.52% of the patients who had fractures in regions related to the inferior alveolar nerve. Temporary mild deficit of the marginal mandibular branch was observed in 2.56% of the extraoral approaches performed and 2.48% presented with hypertrophic scars. Incidence of occlusal alterations was 4.0%. Facial asymmetry was observed in 2.67% of the patients, whereas malunion incidence was 1.78%. Fibrous union, mostly partial, occurred in 2.38% of the fractures, but only 1 of those presented with mobility (0.59%). Condylar resorption developed in 6.25% of the fixated condylar fractures. Mean mouth opening was 42.08 mm. Conclusion: The overall incidence of complications, including infections, was similar to those described for more rigid methods of fixation. © 2003 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 61:430-436, 2003

Suitability of bioresorbable cages for anterior cervical fusion.

The authors conducted a pilot study to determine whether a bioresorbable intervertebral fusion device composed of 85/15 polylactide-polyglycolide (PLA-PGA) copolymer packed with bone autograft is a suitable alternative to promote arthrodesis after anterior cervical discectomy (ACD) in a caprine model. The caprine cervical spine model has been used to evaluate interbody healing and fusion after application of bone grafts and instrumentation. Whether a bioresorbable device is suitable for facilitating intervertebral bone union has not been determined. Twelve goats underwent two-level ACD and fusion; eight received bioresorbable cages packed with autologous bone, and four received autologous bone alone. Goats were maintained without an orthosis and after 12 weeks underwent physical, radiographic, and histological evaluation. Cages had structurally degraded, and two had become extruded. Stable intervertebral union developed in three (19%) of 16 cage-implanted interspaces, and one (14%) of seven bone autograft-implanted interspaces; each was judged manually to be rigid (Grade 2), radiographically to be bridged by new osseous densities (Grade 2), and histologically to have marked new bone formation (Grade 3). A primarily fibrous union, however, stabilized the cage-implanted interspaces, and eight (50%) had developed a 4 to 6-mm foreign body granuloma. These interposed soft tissues were not present in the stable autologous bone-implanted interspace, which had successfully become fused. Interbody cages composed of 85/15 PLA-PGA copolymer contributed to a stable fibrous union, degraded. and produced granuloma after 12 weeks. Additional evaluations are necessary to determine whether other copolymer mixtures, or other bioresorbable materials, can contribute to an arthodesis without deleterious consequences.

Percutaneous internal fixation of selected scaphoid nonunions with an arthroscopically assisted dorsal approach.

Preliminary reports have indicated that selected scaphoid nonunions-i.e., those that are well aligned and without extensive sclerosis or bone resorption at the nonunion site-can be treated effectively with internal fixation alone. We examined the feasibility of percutaneous fixation in a series of such nonunions. A consecutive series of fifteen patients with fibrous union or nonunion of a carpal scaphoid fracture with minimal sclerosis or resorption at the nonunion site were treated with rigid fixation alone (without bone graft) with a headless compression screw inserted with a dorsal percutaneous technique. Clinical examination, standard radiographs, and computed tomography scans confirmed union in all patients at an average of fourteen weeks. Nonunions treated less than six months after the injury healed faster than those treated later (p < 0.02). According to the Mayo modified wrist score, there were twelve excellent and three good results. The results in our series were due to careful examination and grading of the scaphoid nonunions preoperatively. The findings in this small series support the observation in earlier reports that percutaneous repair of selected scaphoid nonunions requires only rigid fixation to achieve healing.

4:16 Reconstruction of complex craniocervical pathology with transarticular screws: assessment of long-term follow-up and quantitative evaluation of screw accuracy by computed tomography

Purpose of study: Transarticular screws are an important option for managing C1–C2 instability, although long-term follow-up on efficacy, safety and application to complex occipitocervical reconstructions is required. To address these issues, we present our experience with transarticular screw fixation in 51 consecutive, prospective cases with a mean follow-up of over 2 years.Methods used: Indications for surgery included trauma (n=23), rheumatoid arthritis (n=13), failed fusion (n=12), degenerative instability (n=3), osteomyelitis (n=1) and os odontoidum (n=1). A C1–C2 fusion alone was performed in 37 cases, and transarticular screws were used as part of a complex reconstruction in 14 cases. Ninety-eight screws were positioned; four patients had a single C1–C2 screw. All cases were evaluated by lateral flexion-extension films. Postoperative computed tomography (CT) with thin cut reconstruction was obtained in 31 cases (60 screws). An index of relative anterior/posterior subluxation was measured on midline sagittal reconstructions.of findings: There were no neurological complications or vertebral artery injuries. A solid fusion was obtained in 46 of 51 cases with four stable fibrous unions and one asymptomatic pseudarthrosis. By CT criteria, screws were in excellent (n=20), good (n=17), acceptable (n=14) and poor (n=2) position. We found a strong correlation between greater than 4 mm of C1–C2 posterior subluxation and nonoptimal screw position (p<.001).Relationship between findings and existing knowledge: The findings in the present study validate the use of transarticlar screw fixation to manage complex craniocervical problems including revision and rheumatoid cases. The zero incidence of neurovascular injury compares favorably with published series that quote up to a 1.8% incidence of vertebral artery injury.Overall significance of findings: Transarticular screws represent an important technique to stabilize the C1–C2 joint and with experience can be placed with minimal risk. Cases of atlantoaxial instability with greater than 4 mm of nonreducible posterior subluxation are associated with poor fixation and should be considered a relative contraindication for this technique.Disclosures: Device or drug: transarticular screw fixation. Status: investigational.Conflict of interest: Michael Fehlings, grant research support, Synthesspire, Medtronic Sofamor Danek.

Traumatic Enucleation of the Body of the Sixth Cervical Vertebra Without Neurologic Sequelae

Case report of an adult man with traumatic enucleation of the body of the sixth cervical vertebra with initial minimal neurologic damage and without vascular injury, which was successfully treated with surgery. To describe the traumatic mechanism, diagnostic procedures, operative findings, and adopted management. Literature review suggests that the observed case is exceptional. Similar vertebral injuries are usually associated with severe neurologic and vascular damages. A 38-year-old farmer with enucleation of the body of the sixth cervical vertebra was admitted to the Orthopedic Clinic of Padua University. The patient initially was treated with halo traction. Two days later, he underwent anterior open reduction and internal fixation with plate. He was discharged 2 months later with a halo vest. Two years after surgery, the pedicles' fracture had healed solidly with normal intervertebral alignment and a slight loss of the height of the C6-C7 intervertebral space (fibrous union). He is asymptomatic and has totally resumed his habitual work. Traumatic enucleation of the body of a lower cervical vertebra is a rare injury. The case presented here demonstrates that such a lesion can be less severe than a complete dislocation or a burst fracture. The good outcome of surgery suggests that the treatment adopted was effective, although an interbody fusion would have been more adherent to conventional surgical principles.

An experimental model of osteoarthrosis of the temporomandibularjoint in monkeys

The purpose of this study was to develop a model of osteoarthrosis of the temporomandibular joint in monkeys, which is remarkably similar in structure and function to that of humans. Nine juvenile monkeys, two as controls and seven as an experimental group, were used in this study. In the experimental group, the articular eminence on both sides was surgically made steeper. Two animals were killed at 1 week, four at 6 months, and one at 1 year postoperatively and the temporomandibular joints were examined macroscopically and microscopically. Typical changes of osteoarthrosis were observed in the 6-month and 1-year specimens. These comprised clustering of chondrocytes which resulted in vertical and horizontal splitting in the articular cartilage, and fibrillation of the articular surface resulting in fibrous union in the joint cavity. These degenerative changes advanced progressively over time. Slight anterior displacement and degenerative changes in the articular disc were also seen.

One- and two-level anterior cervical discectomy and fusion: the effect of plate fixation

Background context: The success of arthrodesis for anterior cervical fusion depends on several factors, including the number of surgical levels. Internal fixation putatively improves the arthrodesis rate and outcome. Purpose: To provide medium-term follow-up data on the surgical success and patient outcome of one- and two-level anterior cervical discectomies and fusions and to determine the effect that plate fixation has on results. Study design: A prospective study of 40 patients who underwent modified Smith-Robinson anterior cervical discectomy and fusion at one or two operative levels. Patient sample: Forty patients. Outcome measures: Odom criteria, Nurick grading system, radiographs. Methods: Forty patients, with an average age of 44 years (range, 27 to 82), were followed for an average of 51 months (range, 24 to 85). All had an anterior discectomy, burring of the end plates and placement of an autogenous tricortical iliac crest graft at one (20 patients) or two levels (20 patients). Twenty-three were stabilized with the Cervical Spine Locking Plate (Synthes Spine, Paoli, PA), 4 single level, 19 two level. All patients had follow-up office visits with examinations and radiographs. Radiographic union, postoperative pain relief and neurologic recovery were evaluated. Results: Successful arthrodesis of single-level procedures occurred in 11 of 16 unplated and 2 of 4 plated fusions. Primary bony union in the two-level group was achieved in 15 of 19 plated patients and did not occur in the single unplated procedure. Clinically, there were 12 excellent, 5 good, 3 satisfactory and 0 poor outcomes among the single-level procedures. Among the dual-level procedures, there were 10 excellent, 5 good, 3 satisfactory and 2 poor results. Nine of 16 who developed adjacent-level degeneration had pain. Five of the 9 also had nonunions. Of the 40, 3 had fibrous union at final follow-up, and 10 had revision surgery. Conclusions: The Cervical Spine Locking Plate improved the outcome of two-level procedures to that of uninstrumented one-level fusions. Adjacent-level degeneration is associated with persistent pain, especially if there is also a nonunion. Primary bony union is paralleled by a better clinical outcome.

Transport distraction osteogenesis: a new method to heal adult calvarial defects.

Popularized by Gavril Ilizarov in the 1960s, monofocal distraction osteogenesis has become a well-established method of endogenous bone engineering. This revolutionary surgical technique has significantly augmented the available reconstructive orthopedic and craniomaxillofacial procedures. Bifocal distraction osteogenesis, or bone transportation, is a modification of monofocal distraction that involves moving a free segment of living bone to fill an intercalary bone defect. Bifocal distraction has been applied successfully to reconstruct complex mandibular and long bone defects. Because traumatic or postsurgical calvarial defects do not spontaneously heal in humans older than 18 to 24 months of age, we hypothesized that bifocal distraction osteogenesis could be applied to the skull to close critical size calvarial defects. Critical size (15 x 15 mm) calvarial defects were created in eight New Zealand White rabbits. Next, a 15-mm x 10-mm calvarial box osteotomy was created just anterior to the skull defect. This osteotomy created a free bone segment that could be transported. A custom-made transport distraction device was fixed into place and the skin incision was closed. After a 4-day latency period, the distraction device was activated (0.5 mm once daily for 30 days) in seven animals; the distraction device in one animal was not activated and served as a control. All animals underwent 30 days of consolidation and were then killed. Radiographs and computed tomographic scans were performed at the following time points: end of latency period (postoperative day 4), mid-distraction (postoperative day 19), and end of consolidation period (postoperative day 64). Gross and histologic analysis was performed to evaluate the quality of the bony regenerate. The control animal healed with a fibrous union. Complete closure of the skull defects was observed in five of seven rabbits at the end of the consolidation period. One animal was removed from the study because of an early loosening of the distraction device, and one was removed because of device failure. Of the remaining five animals that completed the distraction protocol, radiographs and computerized tomographic scans showed successful ossification in all five rabbits at the end of the consolidation period. This study suggests that transport distraction osteogenesis is a promising technique that may be applied to a variety of commonly encountered craniofacial problems such as nonhealing calvarial defects.