[Intraoperative stress in orthopaedic spine surgery : Attending surgeon versus resident]

INTRODUCTION

Requirements for orthopaedic spine surgeons include occupational skills, concentration, physical fitness and psychological stress resistance, depending on the attending surgeon's or the resident's position.

MATERIAL AND METHODS

This study measured and evaluated stress-relevant cardiovascular parameters during 101 spinal surgical procedures of a 40-year old fellowship-trained spine surgeon with 12 years of practice. A training computer, personal scales and a thermometer were used to record the duration of surgery, heart rate, weight loss and calorie burning.

RESULTS

The average maximum heart rate as an attending surgeon (124 bpm) was significantly higher than the resident's heart rate (99 bmp). A higher stress level resulted in an increasingly higher average maximum heart rate according to the duration of surgery. The mean loss of body fluids at an average room temperature of 20.4 C after surgery was 0.82 kg (0 to 2.3 kg). The mean loss of body weight was calculated as 1.12% of the attending surgeon versus 0.59% of the resident.

DISCUSSION

Increasing complexity, longer duration and a higher potential of intraoperative complications arouse a strong response from the attending surgeon. The observed cardiovascular parameters are similar to those of a moderate to intense workout such as cycling. Long lasting surgeries result in a weight loss equivalent to a mild dehydration ranging from 2 to 5% of body fluids. Increasing dehydration will eventually worsen cognitive, visual and motor skills. Results of this study suggest early rehydration and utilization of mental relaxation techniques to minimize risks during prolonged, complex spine surgeries.

[The AOSpine Classification of Thoraco-Lumbar Spine Injuries]

Optimal treatment of injuries to the thoracolumbar spine is based on a detailed analysis of instability, as indicated by injury morphology and neurological status, together with significant modifying factors. A classification system helps to structure this analysis and should also provide guidance for treatment. Existing classification systems, such as the Magerl classification, are complex and do not include the neurological status, while the TLICS system has been accused of over-simplifying the influence of fracture morphology and instability. The AOSpine classification group has developed a new classification system, based mainly upon the Magerl and TLICS classifications, and with the aim of overcoming these drawbacks. This differentiates three main types of injury: Type A lesions are compression lesions to the anterior column; Type B lesions are distraction lesions of either the anterior or the posterior column; Type C lesions are translationally unstable lesions. Type A and B lesions are split into subgroups. The neurological damage is graded in 5 steps, ranging from a transient neurological deficit to complete spinal cord injury. Additional modifiers describe disorders which affect treatment strategy, such as osteoporosis or ankylosing diseases. Evaluations of intra- and inter-observer reliability have been very promising and encourage the introduction of this AOSpine classification of thoracolumbar injuries to the German speaking community.

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, Internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

The second, internet-based multicenter study (MCSII) of the Spine Study Group of the German Association of Trauma Surgery (Deutsche Gesellschaft für Unfallchirurgie) is a representative patient collection of acute traumatic thoracolumbar (T1-L5) injuries. The MCSII results are an update of those obtained with the first multicenter study (MCSI) more than a decade ago. The aim of the study was to assess and bring into focus: the (1) epidemiologic data, (2) surgical and radiological outcome, and (3) 2-year follow-up (FU) results of these injuries. According to the Magerl/AO classification, there were 424 (57.8%) compression fractures (A type), 178 (24.3%) distractions injuries (B type), and 131 (17.9%) rotational injuries (C type). B and C type injuries carried a higher risk for neurological deficits, concomitant injuries, and multiple vertebral fractures. The level of injury was located at the thoracolumbar junction (T11-L2) in 67.0% of the case. 380 (51.8%) patients were operated on by posterior stabilization and instrumentation alone (POSTERIOR), 34 (4.6%) had an anterior procedure (ANTERIOR), and 319 (43.5%) patients were treated with combined posteroanterior surgery (COMBINED). 65% of patients with thoracic (T1-T10) and 57% with lumbar spinal (L3-L5) injuries were treated with a single posterior approach (POSTERIOR). 47% of the patients with thoracolumbar junction (T11-L2) injuries were either operated from posterior or with a combined posterior-anterior surgery (COMBINED) each. Short angular stable implant systems have replaced conventional non-angular stable instrumentation systems to a large extent. The posttraumatic deformity was restored best with COMBINED surgery. T-spine injuries were accompanied by a higher number and more severe neurologic deficits than TL junction or L-spine injuries. At the same time T-spine injuries showed less potential for neurologic recovery especially in paraplegic (Frankel/AISA A) patients. 5% of all patients required revision surgery for perioperative complications. Follow-up data of 558 (76.1%) patients were available and collected during a 30-month period from 1 January 2004 until 31 May 2006. On average, a posterior implant removal was carried out in a total of 382 COMBINED and POSTERIOR patients 12 months after the initial surgery. On average, the rehabilitation process required 3-4 weeks of inpatient treatment, followed by another 4 months of outpatient therapy and was significantly shorter when compared with MCSI in the mid-1990s. From the time of injury until FU, 80 (60.6%) of 132 patients with initial neurological deficits improved at least one grade on the Frankel/ASIA Scale; 8 (1.3%) patients deteriorated. A higher recovery rate was observed for incomplete neurological injuries (73%) than complete neurological injuries (44%). Different surgical approaches did not have a significant influence on the neurologic recovery until FU. Nevertheless, neurological deficits are the most important factors for the functional outcome and prognosis of TL spinal injuries. POSTERIOR patients had a better functional and subjective outcome at FU than COMBINED patients. However, the posttraumatic radiological deformity was best corrected in COMBINED patients and showed significantly less residual kyphotic deformity (biseg GDW -3.8° COMBINED vs. -6.1° POSTERIOR) at FU (p = 0.005). The sagittal spinal alignment was better maintained when using vertebral body replacement implants (cages) in comparison to iliac strut grafts. Additional anterior plate systems did not have a significant influence on the radiological FU results. In conclusion, comprehensive data of a large patient population with acute thoracolumbar spinal injuries has been obtained and analyzed with this prospective internet-based multicenter study. Thus, updated results and the clinical outcome of the current operative treatment strategies in participating German and Austrian trauma centers have been presented. Nevertheless, it was not possible to answer all remaining questions to contradictory findings of the subjective, clinical outcome and corresponding radiological findings between different surgical subgroups. Randomized-controlled long-term investigations seem mandatory and the next step in future clinical research of Spine Study Group of the German Trauma Society.

A new distractable implant for vertebral body replacement: biomechanical testing of four implants for the thoracolumbar spine

INTRODUCTION

Expandable titanium implants for vertebral body replacement in the thoracolumbar spine have been well established in the reconstruction of the anterior spinal column. Load transfer at the bone-implant interface remains a point of concern. The purpose of the study was to compare the performance in axial load transfer from the implant to the vertebral body in four different implants, all of them in clinical use to date.

MATERIALS AND METHODS

We tested a second generation implant (Synex II) in comparison to three different expandable titanium cages: Synex I, Obelisc and X-Tenz. Twenty-four intact fresh frozen human lumbar vertebrae (L1-L4) were distributed into four identical groups according to bone mineral density (BMD). The BMD was determined by quantitative computed tomography (qCT). Specimens were loaded in craniocaudal direction with a material testing machine (Mini Bionix II) at a constant speed of 5 mm/min. Load displacement curves were continuously recorded for each specimen until failure (diminishment of compressive force (F) and/or obvious implant migration through the vertebral body end plate). One-way analysis of variance (ANOVA) and post-hoc tests (Bonferroni) were applied to detect differences at 1, 2, 3, and 4 mm displacement (F (1-4 mm)) between implant groups.

RESULT

No significant differences were observed with regard to maximum compression force (F (max)) and displacement (d (max)) until failure: Synex II (1,782.3 N/4.67 mm); Synex I (1,645.3 N/4.72 mm); Obelisc (1,314.0 N/4.24 mm); X-Tenz (1470.3 N/6.92 mm). However, the mean compression force at 1-4 mm displacement (F (1-4 mm): 300-1,600 N) was highest for Synex II. The difference at 2 mm displacement was significant (p = 0.028) between Synex II (F (2 mm) = 879 N) and X-Tenz (F (2 mm) = 339 N).

CONCLUSION

The modified end plate design of Synex II was found to perform comparably at least with regard to the compressive performance at the implant-bone interface. The risk of the new implant for collapse into the vertebral body might be reduced when compared to the competitors.

[Operative treatment of traumatic fractures of the thorax and lumbar spine. Part II: surgical treatment and radiological findings]

The Spine Study Group (AG WS) of the German Trauma Association (DGU) presents its second prospective Internet-based multicenter study (MCS II) for the treatment of thoracic and lumbar spinal injuries. This second part of the study report focuses on the surgical treatment, course of treatment, and radiological findings in a study population of 865 patients. A total of 158 (18,3%) thoracic, 595 (68,8%) thoracolumbar, and 112 (12,9%) lumbar spine injuries were treated. Of these, 733 patients received operative treatment (OP group). Fifty-two patients were treated non-operatively and 69 patients were treated with kyphoplasty/vertebroplasty without additional instrumentation (Plasty group). In the OP group, 380 (51.8%) patients were instrumented from a posterior (dorsal) position, 34 (4.6%) from an anterior (ventral) position, and 319 (43.5%) cases with a combined posteroanterior procedure. Angular stable internal spine fixator systems were used in 86-97% of the cases for posterior and/or combined posteroanterior procedures. For anterior procedures, angular stable plate systems were used in a majority of cases (51.1%) for the instrumentation of mainly one or two segment lesions (72.7%). In 188 cases (53,3%), vertebral body replacement implants (cages) were used and were mainly implanted via endoscopic approaches (67,4%) to the thoracic spine and/or the thoracolumbar junction. The average operating time was 152 min in posterior-, 208 min in anterior-, and 298 min in combined postero-anterior procedures (p<0,001). The average blood loss was highest in combined operations, measuring 959 ml vs. 650 ml in posterior vs. 534 ml in anterior operations (p<0,001).Computer-assisted intraoperative navigation systems were used in 95 cases. At the time of hospital admission, 58,7% of the patients had spinal canal narrowing of an average of 36% (5-95%) at the level of their injury. The average spinal canal narrowing in patients with a complete spinal cord injury (Frankel/ASIA A) was calculated to be 70%, vs. 50% in patients with incomplete neurologic deficits (Frankel/ASIA B-D), and 20% in patients without neurologic deficits (Frankel/ASIS E; p<0,001). The average procedure in the plasty treatment subgroup was 50 min (18-145 min) to address one (n=59) or two (n=10) injured vertebral bodies. In patients with nonoperative treatment mainly three-point-corsets (n=36) were administered for a duration of 6-12 weeks. During their hospital stay 93 of 195 (44,7%) patients with initial neurologic deficits improved at least one Frankel/ASIA grade until the day of discharge. Two patients (0,2%) showed a neurologic deterioration. The highest rate of complete spinal cord injury (n=36, 23%) was associated with thoracic spine injuries. Nine (1%) patients died during the initial course of treatment. A total of 105 (14,3%) cases with intraoperative (n=56) and/or postoperative complications (n=69) were registered. The most common intraoperative complication was bleeding (n=35, 4,8%). A higher relative frequency of intraoperative complications was noticed in combined (n=34, 10,7%) vs. isolated posterior (n=22, 5,9%; p=0,021) procedures. The most common postoperative complication was associated with wound healing problems in 14 (1,9%) patients. Except in the non-operative treatment subgroup, a correction of the posttraumatic measured radiological deformity was achieved to a different extent within every treatment subgroup. There were no statistically significant differences between the postoperative radiological results of the treatment subgroups (dorsal vs. combination), taking into consideration the influence of relevant parameters such as different fracture types, patient age, and the amount of posttraumatic deformity (p=0,34, ANOVA).

Deformation twinning in Ni-Mn-Ga micropillars with 10M martensite

The maximum actuation frequency of magnetic shape-memory alloys (MSMAs) significantly increases with decreasing size of the transducer making MSMAs interesting candidates for small scale actuator applications. To study the mechanical properties of Ni-Mn-Ga single crystals on small length scales, two single-domain micropillars with dimensions of 10x15x30 mum(3) were fabricated from a Ni-Mn-Ga monocrystal using dual beam focused ion beam machining. The pillars were oriented such that the crystallographic c direction was perpendicular to the loading direction. The pillars were compressed to maximum stresses of 350 and 50 MPa, respectively. Atomic force microscopy and magnetic force microscopy were performed prior to fabrication of the pillars and following the deformation experiments. Both micropillars were deformed by twinning as evidenced by the stress-strain curve. For one pillar, a permanent deformation of 3.6% was observed and ac twins (10M martensite) were identified after unloading. For the other pillar, only 0.7% remained upon unloading. No twins were found in this pillar after unloading. The recovery of deformation is discussed in the light of pseudoelastic twinning and twin-substrate interaction. The twinning stress was higher than in similar macroscopic material. However, further studies are needed to substantiate a size effect.

Combined posterior-anterior stabilisation of thoracolumbar injuries utilising a vertebral body replacing implant

The authors report on a prospectively followed series of 35 patients with injuries of the thoracolumbar spine from T7 to L3. The radiological course after combined posterior-anterior surgery with anterior column reconstruction with a distractible vertebral body replacing implant demonstrated a stable reconstruction technique with almost no re-kyphosing. In 18/18 patients with CT follow-up intervertebral fusion was observed as bony bridging lateral to the VBR implant. The functional/clinical outcome of the patients was analysed with a set of eight validated outcome scales. After an average follow-up period of 2(1/2) years encouraging results were noticed. The neurological improvement rate (> or =1 Frankel/ASIA grade) was 8/12 patients (67%) with a complete recovery in 6 cases. 17/29 patients returned to former occupation; 20/29 patients returned to former leisure activities; 24/28 patients rated their general outcome as "unlimited and pain free" or "occasionally and/or mild complaints" with a VAS score of >80 (scale 0-100). The psychometric questionnaires revealed good results with strong correlation comparing the different scoring systems statistically: mean McGill Pain Questionnaire 12.5 (0-40); mean Oswestry Disability Index 20% (0-51). 13/29 patients scored <4 in the Roland and Morris Disability Questionnaire. The German back pain questionnaire (Funktionsfragebogen Hannover Rücken) showed a mean "functional capacity" of 75%, corresponding with moderate restriction. We concluded the presented method as highly effective to completely reduce and maintain an anatomic spinal alignment. The outcome tended to be better in comparison with non-operatively treated patients as well as with norm populations with low back pain.

[Reduction of traumatic dislocations and facet fracture-dislocations in the lower cervical spine]

BACKGROUND

Traumatic facet dislocations and facet-fracture dislocations in the lower cervical spine (C2/C3 to C7/T1) are frequently associated with devastating neurological symptoms. A good outcome can only be achieved if the operator has wide and sound knowledge of reduction techniques and the best possible strategy is devised for the subsequent treatment of these severe lesions.

PATIENTS AND METHODS

Between 1973 and 1997 a total of 117 of our patients met at least one of the following inclusion criteria: unilateral locked facet dislocation (48%), bilateral locked facet dislocations (23%), unilateral "perched" facet subluxation (14%), bilateral perched facet subluxation (12%), uni- or bilateral dislocation/perched subluxation with facet fractures (3%).

RESULTS

Most of the lesions were located at the levels of C5/C6 and C6/7 (n=46 for each). Associated neurological deficits were present initially in 65% of patients: 35% had complete or incomplete spinal cord injuries (tetraplegia), 2% were paraplegic, and 28% had cervical radiculopathies.

CONCLUSIONS

Closed reduction (e.g. with the aid of a halo ring) should be carried out as soon as possible after lower cervical spine dislocation or facet-fracture dislocation, as both the success rate of reduction and the potential for recovery from neurological deficits are clearly higher when reduction is achieved within the first 4 h after the initial injury.

[An improved vertebral body replacement for the thoracolumbar spine. A biomechanical in vitro test on human lumbar vertebral bodies]

BACKGROUND

In recent years, the use of expandable titanium cages for vertebral body replacement in the thoracolumbar spine has been well established for the treatment of tumors, unstable traumatic lesions, or posttraumatic deformity. Collapse of the implant into the vertebral body remains a point of concern. A biomechanical compression test was designed to assess implant subsidence for a newly developed prototype for vertebral body replacement in the thoracolumbar spine using human cadaveric lumbar vertebrae. The objective of this study was to compare the compressive performance of a new expandable cage with modified end-plate design with three commonly available expandable cages for vertebral body replacement.

MATERIALS AND METHODS

The compressive strengths at the implant-vertebral body interface were measured via axial loading of the new prototype (Synex II) in comparison with three different expandable titanium cages: Synex I (Synthes), Obelisc (Ulrich Medical) and X-Tenz (DePuy Spine). Twenty-four intact, fresh frozen human lumbar vertebrae (L1-L4) were distributed into four identical groups according to BMD (determined by quantitative computed tomography) and the vertebral level. Specimens were loaded in the craniocaudal direction with a material testing machine at a constant speed of 5 mm/min. Load displacement curves were continuously recorded for each specimen until failure (diminishment of compressive force (F)/obvious implant migration through the vertebral body endplate). One-way analysis of variance and post-hoc tests (Bonferroni) were applied to detect differences at 1, 2, 3, 4 mm displacement (F1-4 mm), and Fmax between implant groups.

RESULTS

The four expandable cages did not show statistically significant biomechanical differences in terms of maximum compression force (Fmax) until failure: Synex II (1,782 N/4.7 mm); Synex I (1,645 N/4.7 mm); Obelisc (1,314 N/4.2 mm); X-Tenz (1,470 N/6.9 mm). However, the mean compression force until 4 mm displacement (F1-4 mm: 300-1,600 N) was highest for Synex II. The difference at 2 mm displacement was significant (p=0.028) between Synex II (F2 mm=879 N) and X-Tenz (F2 mm=339 N).

CONCLUSION

The modified endplate design of the new prototype was found to improve its compressive performance under constrained uniaxial loading conditions at the implant-bone interface. The improved compressive behaviour of the new implant might help to reduce the risk of implant subsidence and collapse into the vertebral body in vivo.

Acute traumatic L5-S1 spondylolisthesis: a case report

STUDY DESIGN

Case report of a patient treated surgically 2 months after sustaining a misdiagnosed acute traumatic lumbosacral dislocation is presented.

OBJECTIVES

The aims is to report in full about an uncommon case of anterior traumatic L5-S1 spondylolisthesis treated successfully with combined posterior stabilization and anterior fusion.

SUMMARY OF BACKGROUND DATA

Review of literature shows that traumatic lumbosacral dislocations and its treatment by open reduction and internal fixation are rare with only few well-documented case reports.

METHODS

We report the case of a 37-year-old man, who sustained a work-related traumatic lumbosacral dislocation. The delayed diagnosis of traumatic L5-S1 spondylolisthesis was initially missed and first treated, when the patient was transferred to the author's institution because of persistent neurological deficits. In the following the patient was successfully reduced and stabilized with posterior internal fixation and anterior interbody fusion. This case is documented in detail with radiographs, CT and MRI scans, as well as clinical pictures.

RESULTS

At a 1.5-year follow-up complete fusion was achieved. The patient returned to work on the same job before injury, ambulating pain-free with a good subjective back-function and no limitations carrying out his recreational activities. At follow-up he had persistent sensible S1 nerve root deficits (ASIA grade E).

CONCLUSIONS

Traumatic lumbosacral spondylolisthesis is a rare injury pattern. Its diagnosis can be missed initially, therefore computed tomography with biplanar reconstructions is mandatory in addition to good-quality conventional radiographs to plan and carry out such challenging management problems successfully. Surgical treatment for reduction, stabilization and interbody fusion is the method of choice.

Verletzungen der unteren Halswirbelsäule

Injuries to the subaxial cervical spine (C3-7) occur mostly from traffic accidents and in recreational activities. Such lesions that appear on roentgenological or magnetic resonance images must be classified according to stability. Neurologic deficits, accompanying injuries, and the patient's general condition play major roles in the choice of therapy. Fracture and fracture dislocations should be reduced as soon as possible, as neurologic regeneration and successful reduction are closely time related. The classification developed by Magerl et al. for thoracic and lumbar spine can also be used for the lower cervical spine. Stable injuries without neurologic deficits can generally be treated functionally and, sometimes, with external immobilization. Unstable injuries should be stabilized and treated surgically. Ventral intercorporal spondylodesis is a proven, standard surgical technique for open reduction, decompression, and fusion. Disc and whole or partial vertebral resection along with intercorporal fusion with autologous iliac crest bone grafting and plate osteosynthesis enables successful stabilization of almost all mono- and bisegmental lesions. Dorsal surgery is indicated only in case of a compressed spinal canal and/or neuroforamens due to destroyed posterior elements or remaining instability following ventral plate spondylesis.

Improved anchorage in osteoporotic vertebrae with new implant designs

The goal of our study was to evaluate two newly developed implant designs and their behavior in terms of subsidence in lumbar vertebral bodies under cyclic loading. The new implants were evaluated in two different configurations (two small prototypes vs. one large prototype with similar load-bearing area) in comparison to a conventional screw-based implant (MACS TL). A pool of 13 spines with a total of 65 vertebrae was used to establish five testing groups of similar bone mineral density (BMD) distribution with eight lumbar vertebrae each. In additional to BMD assessment via dual-energy X-ray absorptiometry, cancellous BMD and structural parameters were determined using a new generation in vivo 3D-pQCT. The specimens were loaded sinusoidally in force control at 1 Hz for 1000 cycles at three load levels (100, 200, and 400 N). A survival analysis using the number of cycles until failure (Cox regression with covariates) was applied to reveal differences between implant groups. All new prototype configurations except the large cylinder survived significantly longer than the control group. The number of cycles until failure was significantly correlated with the structural parameter Tb.Sp. and similarly with the cancellous BMD for three of five implants. In both large prototypes the cycle number until failure significantly correlated with the preoperative distance to the upper endplates. Although the direct relationship between bone structure or density and mechanical breakage behavior cannot be conclusively proven, all the prototypes adapted for poor bone structure performed better than the comparable conventional implant.

Cervical pedicle screw placement: feasibility and accuracy of two new insertion techniques based on morphometric data

This morphometric and experimental study was designed to assess the dimensions and axes of the subaxial cervical pedicles and to compare the accuracy of two different techniques for subaxial cervical pedicle screw (CPS) placement using newly designed aiming devices. Transpedicular fixation is increasingly used for stabilizing the subaxial cervical spine. Development of the demanding technique is based on morphometric studies of the pedicle anatomy. Several surgical techniques have been developed and evaluated with respect to their feasibility and accuracy. The study was carried out on six conserved human cadavers (average age 85 years). Axes and dimensions of the pedicles C3-C7 (60 pedicles) were measured using multislice computed tomography (CT) images prior to surgery. Two groups consisting of 3 specimens and 30 pedicles each were established according to the screw placement technique. For surgical technique 1 (ST1) a para-articular mini-laminotomy was performed. Guidance of the drill through the pedicle with a handheld aiming device attached onto the medial aspect of the pedicle inside the spinal canal. Screw hole preparation monitored by lateral fluoroscopy. In surgical technique 2 (ST2) a more complex aiming device was used for screw holes drilling. It consists of a frame with a fully adjustable radiolucent arm for carrying the instruments necessary for placing the screws. The arm was angled according to the cervical pedicle axis as determined by the preoperative CT scans. Drilling was monitored by lateral fluoroscopy. In either technique 3.5 mm screws made of carbon fiber polyetheretherketone (CF-PEEK) were inserted. The use of the CF-PEEK screws allowed for precise postoperative CT-assessment since this material does not cause artifacts. Screw placement was qualified from ideal to unacceptable into four grades: I = screw centered in pedicle; IIa = perforation of pedicle wall less than one-fourth of the screw diameter; IIb = perforation more than one-fourth of the screw diameter without contact to neurovascular structures; III = screw more than one-fourth outside the pedicle with contact to neurovascular structures. Fifty-six pedicle screws could be evaluated according to the same CT protocol that was used preoperatively. Accuracy of pedicle screw placement did not reveal significant differences between techniques 1 and 2. A tendency towards less severe misplacements (grade III) was seen in ST2 (15% in ST2 vs. 23% in ST1) as well as a higher rate of screw positions graded IIa (62% in ST2 vs. 43% in ST1). C4 and C5 were identified to be the most critical vertebral levels with three malpositioned screws each. Because of the variability of cervical pedicles preoperative CT evaluation with multiplanar reconstructions of the pedicle anatomy is essential for transpedicular screw placement in the cervical spine. Cadaver studies remain mandatory to develop safer and technically less demanding procedures. A similar study is projected to further develop the technique of CPS fixation with regard to safety and clinical practicability.

Successful posterior interlaminar fusion at the thoracic spine by sole use of beta-tricalcium phosphate

We report on a 43-year-old male who sustained an isolated distraction injury of the thoracic spine Th7/Th8 (AO/ASIF B 2.3) with wedge compression Th8 and sagittal split Th10 without neurological injury. A bisegmental posterior stabilisation and a monosegmental interlaminar fusion was the treatment of choice. A synthetic bone substitute, beta-tricalcium phosphate (beta-TCP, Chronos) without additional autogenous bone was used to achieve the monosegmental posterior fusion. The clinical course was favourable and 10 months postoperatively the implant was removed. On implant removal the CT scan showed a fused segment and intraoperatively it was found that the fusion was solidly healed. A biopsy was taken from the fusion mass and histology showed vital bone that was rich with osteocytes. Noncalcified osteoid surrounding the bone marrow cavity could be identified. Several studies and the reported case might indicate that osteoconductive material alone can be sufficient for achieving a solid fusion.

[Non-operative treatment of thoracolumbar spinal fractures. Long-term clinical results over 16 years]

Non-operative treatment of thoracolumbar fractures remains the standard treatment option for stable and slightly unstable spinal injuries at the level of the lower thoracic and lumbar spine. The purpose of the present retrospective study was to determine the outcome and long-term results of patients treated conservatively using either one of the two major non-operative treatment modalities: (1) functional, or (2) closed reduction and immobilisation by cast. The average follow-up time for the 43 patients reviewed was 16.3 years. They showed a radiologic increase in the average kyphosis angle of 5.2 degrees compared to the time of injury. No difference was noted between early functional therapy and treatment with closed reduction and immobilisation by cast. Patients with initial neurologic impairment showed a significant improvement ( P<0.05) in their neurologic status during the follow-up period. Results of validated psychometric questionnaires (SF-36, FSR, VAS-Spinescore) showed the characteristic pattern of a population with chronic back pain. In conclusion, a radiologic increase in the traumatic kyphotic deformity in patients with a non-operative treatment protocol has to be expected. Measurable negative physical and social long-term consequences can be anticipated after sustaining a type-A fracture of thoracolumbar vertebral bodies. Any correlation between radiologic and functional results has not been observed.

Long-term efficacy of preseasonal grass pollen immunotherapy in children

BACKGROUND

In a previous controlled study we demonstrated that preseasonal grass pollen immunotherapy for three years was effective in children. In the current study we examined the same group of patients to see if there is still a benefit six years after discontinuation of treatment.

METHODS

Thirteen of 14 patients with previous specific immunotherapy (SIT) and 10 out of 14 patients of the control group were prospectively followed during the grass pollen season. Outcome measures were seasonal symptom scores for eyes, nose and chest, the use of symptomatic medication and visual analog scale. Objective measures included skin prick test reactivity to seasonal and perennial allergens and conjunctival provocation testing.

RESULTS

During the 13 week observation time scores for overall hayfever symptoms (P < 0.004) and individual symptoms for eyes (P < 0.02), nose (P < 0.04) and chest (P < 0.01) as well as combined symptom and medication scores (P < 0.002) remained lower in the group with previous SIT. Only 23% of patients with previous pollen-asthma who had received SIT experienced pollen-associated lower respiratory tract symptoms compared to 70% in the control group (P < 0.05). There was no significant difference in the use of pharmacological treatment during the pollen season except for asthma medication. The average visual analog scale was lower in the post-SIT group (P < 0.05). Six years after cessation of SIT the immediate skin response to grass pollen remained decreased compared to the reaction of the controls (P < 0.01). There was also a tendency for higher allergen concentration to provoke a conjunctival response in the post-SIT group but without reaching statistical significance. Eight years after commencement of SIT, 61% of the initially pollen-monosensitized children had developed new sensitization to perennial allergens compared to 100% in the control group (P < 0.05).

CONCLUSIONS

There is still a significant clinical benefit six years after discontinuation of preseasonal grass pollen immunotherapy in childhood. SIT in children with pollen-allergy reduces onset of new sensitization and therefore has the potential to modify the natural course of allergic disease.

Transfer of additive "minor-effect" genes for resistance to Puccinia striiformis from Triticum dicoccoides into Triticum durum and Triticum aestivum

Transgressive segregation for higher resistance to stripe rust (Puccinia striiformis) was found in segregating populations of crosses of Triticum dicoccoides × Triticum aestivum and T. dicoccoides × Triticum durum. This indicates that additive "minor-effect" gene resistance to stripe rust can be transferred directly from the wild emmer (AABB) to cultivated tetraploid and hexaploid wheats. Since "major-effect" genes for stripe-rust resistance seem to be limited in number, Triticum dicoccoides appears to be a valuable currently untapped reservoir for additive genes which can be combined with genes existing in the tetraploid and hexaploid wheats.