[Complications of the lumbosacral junction in adult deformity surgery : Indications and technique for posterior and anterior revision surgery]. / Komplikationen des lumbosakralen Übergangs bei Korrektur von Erwachsenendeformitäten : Indikation und Technik dorsaler und ventraler Revisionsoperationen.

BACKGROUND: Surgical correction of ASD can be challenging. The indication for surgery is individual and after specification of the therapeutic goals, detailed planning of the surgery is essential to achieve a good postoperative result. COMPLICATIONS AND INDICATION: The reasons for the comparatively high complication rate are well investigated and are often located at the lumbosacral junction. In addition to negative general factors like osteoporosis, especially undercorrection of the sagittal profile and insufficient lumbo-pelvic stabilization are causative. The main indications for revision surgery are a loss of lordosis due to progressive degeneration of the unfused segment L5/S1 or implant loosening and pseudarthrosis of a failed lumbosacral fusion. TREATMENT: The goals of revision surgery are restoration of the spinal balance as well as stable fixation and fusion in consideration of the general condition of the patient. Besides osteotomies in a previously fused region, especially reinstrumentation of the lumbosacral region can be challenging, although ala-ilium and ilium screws give the greatest stability. Additional anterior intersomatic cages allow for a better fusion rate, and, moreover they provide better lordozation. Each PLIF, TLIF, and ALIF cage has its own specific advantages. This article summarizes the reasons for complications of the lumbosacral junction after ASD correction and describes surgical principles for revision surgery.

Reinforcement of lumbosacral instrumentation using S1-pedicle screws combined with S2-alar screws.

OBJECTIVE: Increasing construct stability of lumbosacral instrumentations using S2-ala screws as an alternate to iliac screws. INDICATIONS: Revision surgery after failed lumbosacral fusion; long instrumentations to the sacrum; L5-S1 fusion without anterior support. CONTRAINDICATIONS: Lack of sacral bone stock. SURGICAL TECHNIQUE: Midline approach. The entry point for S2-ala screws is caudal to the posterior S1 foramen and close to the lateral sacral crest. Screw tract preparation for S2-ala screws necessitates 30-45° angulation in the axial plane. Biplanar fluoroscopy with inlet and outlet views ensure screw accuracy. With S2-ala screws, bicortical fixation is the goal. POSTOPERATIVE MANAGEMENT: Patients are mobilized under the surveillance of physiotherapists on day 1 and released from the hospital after 10 days. Clinical and radiographic controls are performed at 6, 12 and 24 months. RESULTS: Retrospective review of 80 patients undergoing S2-ala screw fixation. Main diagnosis was degenerative lumbar instability, adult scoliosis, high-grade listhesis, and nonidiopathic scoliosis. In 66% of patients, the instrumentation using S2-ala screws was part of a major lumbosacral revision surgery. Follow-up averaged 26 months. There were no deaths or major neurovascular complications. First time fusion rate at L5-S1 was greater than 90%. Eight patients (10%) experienced a complication which could be related to the S2-ala screws. Out of 160 S2-ala screws, 16 screws were judged to cause focal irritation and were removed, indicating a survival rate of 90% for the S2-ala screw.

[Restoration of sagittal balance in treatment of thoracic and lumbar vertebral fractures]. / Wiederherstellung der sagittalen Balance bei der Versorgung thorakaler und lumbaler Wirbelkörperfrakturen.

Posttraumatic kyphosis (PTK) is a possible consequence of a missed fracture, a wrong indication for conservative therapy or an inadequate surgical technique but PTK can also be a complication after adequate surgery. Avoidance of PTK is of importance because subsequent surgical therapy can be extensive. A thorough planning as well as surgical experience with anterior and posterior revision cases is necessary. The various types of osteotomy which allow correction of local as well as global deformities should also be mastered. Knowledge of the principles of sagittal balance and spinopelvic parameters are indispensable in the treatment of PTK. Our experience and results from the literature show that a good long-term outcome with limited complications can only be achieved when considering the biomechanical principles as well as restoration of sagittal balance.

The indication for gamma probe-guided surgery of spinal osteoid osteomas.

The standard treatment for osteoid osteomas is CT-guided radiofrequency ablation (RFA). This minimally invasive procedure is effective in terms of pain reduction as well as the recurrence rate. Nevertheless, the use for spinal lesions is limited due to a possible thermal damage of neural structures. Although the literature is contradictory, RFA should only be used when a cortical shell between the lesion and the spinal canal is existent. We present seven cases (five males, two females, mean age 23 years) with spinal osteoid osteoma in which RFA was not applicable and open resection with the use of probe-guided surgery (PGS) was performed. The principle of PGS is that after preoperative bone scintigraphy, a handheld radiation probe is used intraoperatively for tumour localisation. Here, exposure and bone resection can be minimised and completeness of tumour excision may be estimated. At the initial measurement we found a hot-spot (maximum count-rate) in all patients and after tumour resection, the signal decreased by a mean of 68% in the operative field. After a mean follow-up of 17 months one patient had residual pain but no patient had signs of tumour recurrence. The authors recommend to use PGS for those spinal osteoid osteomas where RFA is not applicable and intraoperative localisation--and here complete resection--of the tumour is difficult.

Is anterior release effective to increase flexibility in idiopathic thoracic scoliosis? Assessment by traction films.

With the advent of thoracoscopy, anterior release procedures in adolescent idiopathic scoliosis (AIS) have come into more frequent use, however, the indication criteria for an anterior release in thoracic AIS are still controversial in the literature. To date, few studies have assessed the influence on spinal flexibility and no study has so far been able to show a beneficial effect on the correction rate as compared to a single posterior procedure. The objective of this study was to evaluate the influence of thoracic disc excision on coronal spinal flexibility. Six patients (5 females, 1 male) with AIS and a mean age of 15.6 years (range 13-20 years) underwent an open anterior thoracic release prior to posterior instrumentation. Cotrel dynamic traction along with radiographs of the whole spine including traction films were conducted pre- and postoperatively and were evaluated retrospectively. The mean preoperative thoracic curve was 89.7 degrees +/- 15.4 degrees (range 65 degrees-110 degrees). The flexibility rate in Cotrel traction was 22.8 +/- 8.1%. After performance of the anterior release the thoracic curve showed a mean increase of coronal correction by 5.5 degrees +/- 5.0 degrees as assessed by traction radiographs. The flexibility index changed by 6.2 +/- 5.6%. After posterior instrumentation the thoracic curve was corrected to a mean of 36.5 degrees +/- 10.1 degrees (correction rate 59.6%). Disc excision in idiopathic thoracic scoliosis only slightly increased spinal flexibility as assessed by traction films. In our view a posterior release with osteotomy of the concave ribs (concave thoracoplasty, CTP) is more effective in increasing spinal flexibility. According to our clinical experience, an anterior release prior to posterior instrumentation in AIS should only be considered in hyperkyphosis, coronal imbalance or massive curves.

Histopathology of cryopreserved bone allo- and isografts: pretreatment with dimethyl sulfoxide.

Partial graft cell survival and enhanced graft revascularization have suggested fast freezing using the cryoprotective substance dimethyl sulfoxide (DMSO) as a promising means to improve the biologic function and immune tolerance of allograft bone. This study determines the presence of osteoblasts (cola(1)(I) mRNA), osteoclasts (TRAP), and cytotoxic T cells (CTLs; GrA mRNA) within pretreated bone grafts 12 days after transplantation. The grafts were transplanted either as isografts, allografts, or allografts in presensitized recipients. In fresh isografts, serving as control, well-formed blood vessels and the highest numbers of viable osteoblasts and osteoclasts were found. In fresh allografts, blood vessels were observed within the marrow cavity and the bone was partially covered by osteoblasts and osteoclasts accompanied by CTLs. In DMSO-pretreated frozen allografts, blood vessels together with osteoblasts were observed in three of five, but in none of five grafts frozen without DMSO. However, infiltration with CTLs was higher in DMSO-pretreated frozen allografts when compared to grafts frozen without DMSO. In presensitized allograft recipients, independent of the pretreatment, in none of the grafts were either blood vessels or osteoblasts found. Thus, fast cryopreservation of bone using DMSO improves vascularization and expression of cola(1)(I) mRNA (osteoblasts) after allografting when compared to cryopreservation alone, potentially improving graft incorporation. As these grafts were still invaded by CTLs, the long-term effect of DMSO pretreatment needs to be defined.

Predictors of humeral head ischemia after intracapsular fracture of the proximal humerus.

The purpose of this study was to evaluate predictors of fracture-induced humeral head ischemia. Between February 1998 and December 2001, 100 intracapsular fractures of the proximal humerus, treated by open surgery, were included in a prospective surgical evaluation protocol (mean age, 60 years; minimum, 21 years; maximum, 88 years; 45 men; 57 right shoulders). Fracture morphology was assessed following a structured questionnaire and based on radiographic and intraoperative findings. Perfusion was assessed intraoperatively by observation of backflow after a borehole was drilled into the central part of the head in all shoulders and by intraosseous laser Doppler flowmetry in 46. Good predictors of ischemia were the length of the metaphyseal head extension (accuracy, 0.84 for calcar segments <8 mm), the integrity of the medial hinge (accuracy, 0.79 for disrupted hinge), and the basic fracture pattern (accuracy, 0.7 for combined types 2, 9, 10, 11, and 12). Moderate and poor predictors of ischemia were fractures consisting of four fragments (accuracy, 0.67), angular displacement of the head (accuracy, 0.62 for angulations over 45 degrees ), the amount of displacement of the tuberosities (accuracy, 0.61 for displacement over 10 mm), glenohumeral dislocation (accuracy, 0.49), head-split components (accuracy, 0.49), and fractures consisting of three fragments (accuracy, 0.38). When the above criteria (anatomic neck, short calcar, disrupted hinge) were combined, positive predictive values of up to 97% could be obtained. The most relevant predictors of ischemia were the length of the dorsomedial metaphyseal extension, the integrity of the medial hinge, and the basic fracture type determined with the binary description system.

Primary subacute epiphyseal and metaepiphyseal osteomyelitis in children. diagnosis and treatment guided by MRI.

We present three children with primary subacute epiphyseal and metaepiphyseal osteomyelitis. The diagnosis was delayed because of subtle radiological findings and mild general symptoms. Primary epiphyseal osteomyelitis is extremely rare. We believe that this is the first time that the MRI findings have been presented. In the first case they revealed a perforation into the knee and therefore an intra-articular epiphyseal approach was used for debridement. In the second and third cases the metaepiphyseal lesions showed considerable physical involvement and a metaphyseal approach was chosen. We believe that in this condition MRI is essential both for diagnosis and in the planning of surgical treatment.

Perfusion of the femoral head during surgical dislocation of the hip. Monitoring by laser Doppler flowmetry.

We used laser Doppler flowmetry (LDF) with a high energy (20 mW) laser to measure perfusion of the femoral head intraoperatively in 32 hips. The surgical procedure was joint debridement requiring dislocation or subluxation of the hip. The laser probe was placed within the anterosuperior quadrant of the femoral head. Blood flow was monitored in specific positions of the hip before and after dislocation or subluxation. With the femoral head reduced, external rotation, both in extension and flexion, caused a reduction of blood flow. During subluxation or dislocation, it was impaired when the posterosuperior femoral neck was allowed to rest on the posterior acetabular rim. A pulsatile signal returned when the hip was reduced, or was taken out of extreme positions when dislocated. After the final reduction, the signal amplitudes were first slightly lower (12%) compared with the initial value but tended to be restored to the initial levels within 30 minutes. Most of the changes in the signal can be explained by compromise of the extraosseous branches of the medial femoral circumflex artery and are reversible. Our study shows that LDF provides proof for the clinical observation that perfusion of the femoral head is maintained after dislocation if specific surgical precautions are followed.

Femoral revision using the Wagner stem: results at 2-9 years.

We followed 39 patients with 40 revision hip arthroplasties using the Wagner stem. Mean follow-up was 65 (29-108) months. There were 12 intraoperative proximal femoral fractures, which all united, five postoperative dislocations not related to subsidence, and two loose stems that were revised. Clinical improvement was best for pain. Once the stem was osteointegrated the clinical and radiological result remained stable for up to 9 years.

Surgical landmarks to determine humeral head retrotorsion for hemiarthroplasty in fractures.

Malrotation has been suggested as a cause of failure of hemiarthroplasty of the proximal humerus. Placing a shoulder prosthesis in relationship to the bicipital groove might reproduce individual anatomy more reliably than using a standardized retrotorsion. The purpose of this study was to determine criteria for accurate adjustment of retrotorsion even when the proximal bicipital groove is destroyed, as is the case in fractures. The distance of the humeral head equatorial plane to the center of the bicipital groove was measured by high-resolution computed tomography at 4 levels (proximal and distal with 2 intermediate levels). The distal distance was considered to correspond to available references in fracture cases. The mean proximal distance was 8.0 mm (10th percentile, 6.2 mm; 90th percentile, 9.8 mm), and the mean distal distance was 8.5 mm (10th percentile, 7.1 mm; 90th percentile, 9.9 mm). As to the clinical relevance, there was no statistically significant difference between distances. For practical purposes in fracture indications, it is adequate to adjust the retrotorsion of the prosthetic component to the distal bicipital groove.

[Evaluation of hydroxyapatite-coated Schanz screws in the Heidelberg external fixation system (HEFS)]. / Evaluation hydroxylapatitbeschichteter Schanz-Schrauben bei Verwendung des Heidelberg External Fixation System (HEFS).

The use of monolateral external fixation systems for the correction of limb length and/or axial anomalies involves the implantation of Schanz screws in the long bones for periods of weeks or months. The loosening rate, which increases with duration of implantation, is a problem. In animal experiments/superior fixation and a reduced infection rate have been reported for hydroxyapatite-coated screws in comparison with conventional screws. We report on the clinical application of 59 hydroxyapatite-coated Schanz screws in 15 external fixation mountings. The performance of the screws was evaluated by clinical and radiological criteria. Infection was seen in 15 screws, necessitating the early removal of 6 of them. In patients with a second fixation system/the infection rate was lower, with infection developing in only 1 of 12 screws.