The Haleem-Marks-Botchu classification: a novel CT-based classification for intracanal rib head penetration.

PURPOSE: Intracanal rib head penetration is a well-known entity in dystrophic scoliotic curves in neurofibromatosis type 1. There is potential for spinal cord injury if this is not recognised and managed appropriately. No current CT-based classification system is currently in use to quantify rib head penetration. This article aims to propose and evaluate a novel CT-based classification for rib head penetration primarily for neurofibromatosis but which can also be utilised in other conditions of rib head penetration. MATERIALS AND METHODS: The grading was developed as four grades: normal rib head (RH) position-Grade 0, subluxed extracanal RH position-Grade 1, RH at pedicle-Grade 2, intracanal RH-Grade 3. Grade 3 was further classified depending on the head position in the canal divided into thirds. Rib head penetration into proximal third (from ipsilateral side)-Grade 3A, into the middle third-Grade 3B and into the distal third-Grade 3C. Seventy-five axial CT images of Neurofibromatosis Type 1 patients in the paediatric age group were reviewed by a radiologist and a spinal surgeon independently to assess interobserver and intraobserver agreement of the novel CT classification. Agreement analysis was performed using the weighted Kappa statistic. RESULTS: There was substantial interobserver correlation with mean Kappa score (k = 0.8, 95% CI 0.7-0.9) and near perfect intraobserver Kappa of 1.0 (95% CI 0.9-1.0) and 0.9 (95% CI 0.9-1.0) for the two readers. CONCLUSION: The novel CT-based classification quantifies rib head penetration which aids in management planning.

The surgical management of spinal deformity in children with a Fontan circulation: The development of an algorithm for treatment.

The management of spinal deformity in children with univentricular cardiac pathology poses significant challenges to the surgical and anaesthetic teams. To date, only posterior instrumented fusion techniques have been used in these children and these are associated with a high rate of complications. We reviewed our experience of both growing rod instrumentation and posterior instrumented fusion in children with a univentricular circulation. Six children underwent spinal corrective surgery, two with cavopulmonary shunts and four following completion of a Fontan procedure. Three underwent growing rod instrumentation, two had a posterior fusion and one had spinal growth arrest. There were no complications following surgery, and the children undergoing growing rod instrumentation were successfully lengthened. We noted a trend for greater blood loss and haemodynamic instability in those whose surgery was undertaken following completion of a Fontan procedure. At a median follow-up of 87.6 months (interquartile range (IQR) 62.9 to 96.5) the median correction of deformity was 24.2% (64.5° (IQR 46° to 80°) vs 50.5° (IQR 36° to 63°)). We believe that early surgical intervention with growing rod instrumentation systems allows staged correction of the spinal deformity and reduces the haemodynamic insult to these physiologically compromised children. Due to the haemodynamic changes that occur with the completed Fontan circulation, the initial scoliosis surgery should ideally be undertaken when in the cavopulmonary shunt stage.

A simplified Galveston technique for the stabilisation of pathological fractures of the sacrum.

Mechanical stabilisation of pathological fractures of the sacrum is technically challenging. There is often inadequate purchase in the sacrum, and stabilisation has to be achieved between the lumbar vertebrae and ilium. We present a simplification of the Galveston technique. We treated a total of six patients with this technique, four for metastatic disease and two for primary tumours. Our technique consists of the formation of a proximal stable construct using ISOLA pedicle screws linked distally using a modular system of connectors to threaded iliac bolts with cross linkages. Neurological decompression and fusion was performed as appropriate. The benefits of this method are: ease of access to the ilium, a solid purchase to the ilium, less rod contouring and shorter operating time. We have had no operative complications from this procedure. All patients were discharged home mobile, with a reduced opiate requirement.

Metaphyseal chondrodysplasia type Schmid mutations are predicted to occur in two distinct three-dimensional clusters within type X collagen NC1 domains that retain the ability to trimerize.

Metaphyseal chondrodysplasia type Schmid (MCDS) is caused by mutations in COL10A1 that are clustered in the carboxyl-terminal non-collagenous (NC1) encoding domain. This domain is responsible for initiating trimerization of type X collagen during biosynthesis. We have built a molecular model of the NC1 domain trimer based on the crystal structure coordinates of the highly homologous trimeric domain of ACRP30 (adipocyte complement-related protein of 30 kDa or AdipoQ). Mapping of the MCDS mutations onto the structure reveals two specific clusters of residues as follows: one on the surface of the monomer which forms a tunnel through the center of the assembled trimer and the other on a patch exposed to solvent on the exterior surface of each monomeric unit within the assembled trimer. Biochemical studies on recombinant trimeric NC1 domain show that the trimer has an unusually high stability not exhibited by the closely related ACRP30. The high thermal stability of the trimeric NC1 domain, in comparison with ACRP30, appears to be the result of a number of factors including the 17% greater total buried solvent-accessible surface and the increased numbers of hydrophobic contacts formed upon trimerization. The 27 amino acid sequence present at the amino terminus of the NC1 domain, which has no counterpart in ACRP30, also contributes to the stability of the trimer. We have also shown that NC1 domains containing the MCDS mutations Y598D and S600P retain the ability to homotrimerize and heterotrimerize with wild type NC1 domain, although the trimeric complexes formed are less stable than those of the wild type molecule. These studies suggest strongly that the predominant mechanism causing MCDS involves a dominant interference of mutant chains on wild type chain assembly.

A similarity model for the human angiogenic factor, thymidine phosphorylase/platelet derived-endothelial cell growth factor.

Thymidine phosphorylase (EC 2.4.2.4), identical to the angiogenic factor, platelet-derived endothelial cell growth factor (PD-ECGF), is up-regulated in several tumour types. A similarity model of human thymidine phosphorylase was built, based on the crystal structure of the Escherichia coli enzyme. The high residue conservation between the two enzyme sources (39% sequence identity and 53% sequence similarity) aided model building. The human model was very similar to the E. coli enzyme's crystal structure, with the main tertiary structure difference being the destruction of helix 15 in E. coli by the presence of a loop in the human model. The model was used to rationalize the nature of the binding of the substrates thymine and thymidine, and of known inhibitors using a quantitative docking algorithm. Ab initio calculations on the nM inhibitor 5-chloro-6-(1-(2-iminopyrrolidinyl)methyl)uracil hydrochloride gave its conformation and distribution of charge. Subsequent quantitative docking studies have led to the suggestion, for the first time, that this inhibitor behaves as an oxycarbenium ion transition-state analogue, explaining its strong reported inhibition.

Autologous bone grafting in staged scoliosis surgery. The patient as bone bank.

STUDY DESIGN: A prospective clinical study in which autologous rib graft, harvested during the thoracotomy in staged scoliosis correction, is stored within the patient for use during the second stage (posterior intrumentation and fusion). OBJECTIVE: To determine whether the bone stored by this technique is biologically viable and microbiologically safe. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, this method of storage of bone has never been described previously. METHODS: During the first operation, the excised rib was divided into 3-5 cm fragments and stored in a sub-muscular plane adjacent to the posterior elements of the spine before closure. The graft was then retrieved at the second stage. Samples were sent for histologic and microbiologic examination before implantation. RESULTS: On histologic examination, more than 50% of the osteocytes retained their basophilic staining, indicating that they were viable. In addition, osteoclastic activity was notably absent. There was no significant bacterial contamination of the samples. Clinically, all patients achieved satisfactory bone fusion. CONCLUSION: Homeostatic equilibrium in humans provides the ideal environment in which bone graft can be stored. There is no increased risk of infection, and the osteogenic potential of the graft is retained.

Convex spinal epiphysiodesis in the management of progressive infantile idiopathic scoliosis.

STUDY DESIGN: Retrospective review of patient records with current clinical and radiographic assessment. OBJECTIVE: To evaluate the long-term result of anterior and posterior convex spinal growth arrest, with or without instrumentation, in managing infantile idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: There were 12 male and 10 female patients studied, with a mean follow-up period of 10 years, 9 months. The mean Cobb angle before surgery was 65 degrees. All had a rib vertebral angle difference more than 20 degrees. The mean age at surgery was 6 years. Nine patients had epiphysiodesis alone; nine patients also underwent Harrington instrumentation simultaneously, and four underwent Harrington instrumentation 2-4 years later. METHOD: Clinical evaluation and sequential measurements of Cobb angle were done. RESULTS: The epiphysiodesis-only group had a mean preoperative Cobb angle of 72 degrees, mean progression of curves of +12 degrees, and mean rate of progression of +2.5 degrees per year: the group's postoperative figures were 92 degrees, +15 degrees, and +3 degrees per year, respectively. The epiphysiodesis and late Harrington rod group had a mean preoperative Cobb angle of 56 degrees, mean progression of +12 degrees, and a mean rate of progression of +5 degrees per year; the group's postoperative Cobb angle averaged 62 degrees, progression +6 degrees, and rate of progression +1 degree per year. The epiphysiodesis with simultaneous Harrington rod group had a preoperative mean Cobb angle of 60 degrees, mean progression of +18 degrees, and mean rate of progression of +6 degrees per years. After surgery, these improved to 58 degrees, correction of 2 degrees, and rate of correction of 0.5 degree per year. CONCLUSION: Combined anterior and posterior convex spinal growth arrest alone does not prevent progression of deformity in infantile idiopathic scoliosis. The addition of posterior instrumentation can slow or arrest deformity progression but not reverse it.

Long-term results of combined anterior and posterior convex epiphysiodesis for congenital scoliosis due to hemivertebrae.

STUDY DESIGN: Retrospective review of patient records with recent clinical and radiologic assessment. OBJECTIVE: To evaluate the long-term result of anterior and posterior convex ephiphysiodesis in the management of congenital scoliosis resulting from fully segmented nonincarcerated hemivertebra. SUMMARY OF BACKGROUND DATA: Thirty patients (16 male/14 female patients) were reviewed. Follow-up was a minimum of 3 years (average, 8 years 10 months; range, 3-22.5 years). Nineteen patients were skeletally mature, and the mean age of the remaining 11 was 11.75 years. METHOD: Clinical evaluation and sequential measurements of Cobb angle was made independently by two observers. RESULTS: Compared with preoperative values, the rate of change in Cobb angle was reversed in 23 patients, arrested or slowed in five patients, and unchanged or progressed in two patients. The annual rate of change in Cobb angle was +1.9 degrees before surgery and -1.2 degrees after surgery, a difference of 3.1 degrees. This is highly statistically significant (P < 0.001). Total correction in Cobb angle correlates with age at time of surgery (P < 0.03). The rate of correction in Cobb angle after surgery correlates with the total correction achieved (P < 0.001) and with age at time of surgery (P < 0.05). The greater correction is achieved when surgery is performed at a young age. The preoperative rate of increase in Cobb angle does not correlate with correction (P < 0.76). The site of the hemivertebrae influenced final outcome with best results in the lumbar spine. CONCLUSION: Combined anterior and posterior convex epiphysiodesis is a reliable method for the correction of deformity resulting from hemivertebrae.

Long-term results of convex epiphysiodesis for congenital scoliosis.

The objective of this study was to evaluate the long term outcome of combined anterior and posterior convex spinal epiphysiodesis in the treatment of congenital scoliosis. The study covered 53 patients (27 male, 26 female) with a minimum follow up period from surgery of 3 years (mean 8.8 years, range 3-22.5 years). Of these, 34 were skeletally mature when reviewed. Clinical assessment and sequential measurement of Cobb angles were used to chart the course of the deformity following surgery. The types of vertebral anomalies encountered were: 4 unsegmented bars, 7 unsegmented bars with hemivertebrae, 30 hemivertebrae (of which 2 were double hemivertebrae) and 12 complex (unclassifiable) patterns. The severe types were concentrated in the thoracic spine. Results are presented with reference to the type and site of anomaly and to the age of the patient at the time of surgery. Where deformity was due to an unsegmented bar (with or without hemivertebra) the rate of change of Cobb angle was slowed, but not reversed, following surgery. For the complex anomalies there was a reduction in the rate of progression of deformity following surgery, however, the final Cobb angle still increased from a mean of 61 degrees to 70 degrees. In contrast, the rate of progression reversed or slowed in 97% of the hemivertebra patients following surgery, producing a change in mean Cobb angle from 41 degrees pre-operatively to 35 degrees post-operatively. For each type of anomaly the correction achieved was greater where the surgery was performed at a younger age. Final outcome was influenced by the site of anomaly, with a better correction being achieved in the lumbar than the thoracic spine. In conclusion, we feel that convex epiphysiodesis has an important role in the surgical management of congenital scoliosis and, for hemivertebrae in particular, it can produce significant correction of deformity.

A homology model of the three-dimensional structure of human O6-alkylguanine-DNA alkyltransferase based on the crystal structure of the C-terminal domain of the Ada protein from Escherichia coli.

O6-Alkylguanine-DNA alkyltransferase (EC 2.1.1.63) repairs O6-alkylguanine lesions in DNA. A homology model of the human protein (hAT) was built, based on the crystal structure of the C-terminal domain of the Ada protein, which carries out a similar repair in Escherichia coli. Sequence alignments of known O6-alkylguanine-DNA alkyltransferases were used to aid the model building using QUANTA and CHARMm software. Despite low homology in the N-terminal half (hAT residues 1-85), a well-defined topology over this region in Ada permitted successful modelling. The C-terminal half of hAT (residues 92-207) was modelled almost entirely by residue-for-residue superposition onto the Ada structure up to residue hAT175. The model was solvated to a residue radius of 8.0 A [corrected] and then minimized using CHARMm. This structural model was used to rationalize findings from site-directed mutagenesis experiments on hAT, to make further predictions on the relationship between structure and function for the alkyltransferase family of proteins, and to explain the specificity towards known small-molecule inhibitors of the protein.

Surgical management of haemangioendothelioma of the spine.

Four patients with haemangioendothelioma of the spine which was treated surgically are presented. Two were male and two female, mean age 30 years (range 5-60). All tumours were sited in the thoracic spine between T5 and T10; three were primary and one metastatic from a hepatic haemangioendothelioma. Each patient had a significant neurological deficit at presentation; three were paraplegic. A diagnosis of vertebral neoplastic disease was suggested on plain radiographs, and in three cases this was supported by computed tomography or magnetic resonance imaging. Two patients underwent anterior decompression and posterior instrumented stabilisation, one anterior decompression alone and one posterior decompression followed by tumour vessel embolisation and then anterior decompression. Intra-operative blood loss was a significant feature despite the use of hypotensive anaesthetic techniques and local haemostatic agents. Three of the tumours were tested for Factor VIII (a tumour for vascular tumours), and all proved positive. In these, sufficient histological material was available to grade the tumours according to the classification of Campanacci et al. [1]. All were grade II. Three patients recovered completely from paraglegia; one had residual mild spasticity which required the use of a walking aid. The mean improvement in Frankel grade was 2.5 (range 1-4). In two the tumour recurred outside the spine within 18 months; one had subsequently died. The presentation, investigation and results of surgery for haemangioendothelioma of the spine are presented. Particular attention is drawn to the neurological status at presentation, the effect of pre-operative tumour embolisation and the dramatic recovery that can be achieved in these patients following surgery.

Routine ultrasound screening for neonatal hip instability. Can it abolish late-presenting congenital dislocation of the hip?

We have undertaken routine ultrasound screening for neonatal hip instability in Coventry since June 1989. Of the 14,050 babies scanned during the first three years, 847 (6%) had ultrasound abnormalities. A grading system, based on the percentage of femoral head coverage, is presented. The proportion of abnormal hips decreased gradually so that by nine weeks, 90% had normal ultrasound appearances. Abnormality was more common in babies with a family history of CDH and in breech presentations. All babies with clinically abnormal hips had an abnormal first ultrasound examination. Five babies not diagnosed by clinical examination and with no risk factors had abnormal ultrasound appearances and were subsequently found to have clinically abnormal hips. Routine ultrasound screening has detected cases which would otherwise have presented late.

Zickel supracondylar nailing for supracondylar femoral fractures in elderly or infirm patients. A review of 33 cases.

We report 33 cases of femoral supracondylar fracture in elderly or debilitated patients treated by Zickel supracondylar nails. Most of the patients were female and their mean age was 79 years. All had concurrent medical problems and only nine could walk unaided. The operating time averaged one hour and mean blood loss was 100 ml. Postoperative management was by mobilisation in a cast brace or plaster. Six patients died before fracture union; all the others achieved union at an average of 12 weeks. The results were excellent in terms of pain relief, movement and function; there were no infections or nonunions. The locking screws backed out or broke in 26% but this did not prejudice the outcome. Use of the Zickel system is recommended for this group of frail patients.

Surgical management of vertebral neoplasia: who, when, how and why?

To determine the role of surgery in vertebral neoplasia, we conducted a retrospective review of patients undergoing surgery for vertebral neoplasia in the Royal Orthopaedic Hospital, Birmingham, and Coventry and Warwickshire Hospital, Coventry. Surgery included decompression, stabilisation or both. The neurological status was assessed by Frankel grading before and after surgery. Of 70 patients undergoing surgery, 14 were neurologically intact preoperatively, and a further 25 were weak but ambulatory. Following surgery, 35 were intact, and a further 22 were ambulatory. Sixty-six patients (94%) obtained good pain relief. Survival correlated with histology and younger age at presentation, but not with level, neurology at presentation or type of surgery. We conclude that neurological status, pain relief and mechanical stability are better after appropriate surgery than after radiotherapy or inappropriate surgery. Failure to consider the surgical option may deny the chance of significant neurological recovery.

A halo jacket for stabilisation of the paediatric cervical spine.

Stabilisation of the paediatric cervical spine may be necessary in the management of trauma, infection and deformity. Surgery is technically difficult due to the immaturity of the bony elements and therefore external support is generally preferred. Our experience of halter traction and Minerva casts is that they either fail to achieve stability or are poorly tolerated. Halo pins are associated with significant pin tract complications in children. The technique for application of a plaster halo jacket is presented, together with the results of its use in eight children. Attention is drawn to the ease of application, tolerance by the patients and absence of significant complications.

Work in progress: radioisotopic evaluation of gastroplasty patients.

Radioisotopic gastric emptying studies, using technetium-99m-sulfur-colloid-labeled egg, were performed in 14 patients who had undergone gastroplasty. The radioisotopic method was found to be a good quantitative indicator of the amount of solids that empty from the stomach and a useful tool in the longterm follow-up of gastroplasty patients. It was particularly helpful in evaluating the efficacy of surgery in patients with poor postsurgical weight reduction.

Differentiation of focal intrahepatic lesions with 99mTc-red blood cell imaging.

The appearance of focal hepatic lesions on 99mTc-sulfur colloid images is nonspecific. As it is important to distinguish hemangiomas from other lesions prior to biopsy, a prospective study was performed using 99mTc-labeled red blood cells. Dynamic perfusion and delayed blood-pool images (1-2 hours) were obtained and lesion activity categorized as increased, equal, or decreased compared with the liver. Of 21 patients studied, 9 (43%) had one or more hepatic hemangiomas, and 8 of these 9 patients (89%) demonstrated increased blood-pool activity. The 12 nonhemangiomatous lesions consisted of 7 metastatic tumors, 2 hepatomas, 1 cirrhotic nodule, and 2 hepatic cysts. None of these 12 patients had increased activity on delayed blood-pool images. Early dynamic images of hepatic hemangiomas demonstrated variable activity (vascularity) and were not useful in differentiating hemangiomas from other lesions. Sensitivity was 89% and specificity 100%. Although liver enzymes are usually normal with hepatic hemangiomas, they may also be normal in metastatic disease. The authors recommend that delayed blood-pool imaging be performed prior to biopsy, particularly in patients without a known primary tumor or those with normal liver enzyme levels.

Surgical results of anomalous left coronary artery.

After undergoing a ligation of the anomalous left coronary artery from the pulmonary artery and a saphenous vein bypass graft surgery, a 53-year-old woman has had improvement in exercise tolerance and congestive heart failure for up to two years of follow-up. Comparison of the preoperative and postoperative noninvasive studies disclose that surgery improved the left ventricular volume overload and perfusion. However, there was no change in the resting or exercise ejection fraction as assessed by stress multiple-gated acquisition isotope scan.

Ultrasonic features and radionuclide correlation in liver cell adenoma and focal nodular hyperlasia.

Ultrasonic features of three cases of liver cell adenoma (LCA) and two cases of focal nodular hyperplasia (FNH) are presented. These tumors have similar sonographic appearances presenting either as solid masses or containing sonolucent areas due to hemorrhage or necrosis. Although these ultrasonic features in patients with an area of decreased activity on 99mTc-sulfur colloid (Tc-SC) liver scans are not specific for LCA or FNH, such findings in the appropriate clinical setting are suggestive of these lesions. The combination of a solid mass on ultrasonography and a normal Tc-SC radioisotope liver study may be relatively specific for uncomplicated FNH.