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✓ Atlantoaxial rotatory fixation (AARF) is an uncommon condition of childhood. Occasionally AARF may recur. The authors describe the cases of four patients with recurrent AARF (RAARF). The probable cause of the RAARF and operative procedure selected are discussed. In three cases, attempts were made to stabilize the atlantoaxial complex rather than to perform fusion to preserve the function of the joint complex. Joint stabilization is performed by incorporating a “check ligament” into the joint construct between the axial spinous process and the atlantal lateral mass. The authors believe this technique of joint stabilization augments the strength of the joint, allowing normal, but preventing excessive, rotation, until the joint reaches physiological maturity.

We present the anaesthetic and surgical management, and post-operative course of a patient with osteogenesis imperfecta which exemplifies the problems associated with this condition. The observed petechial haemorrhagic rash is not characteristic of the bleeding tendency in osteogenesis imperfecta nor characteristic of acute disseminated intravascular coagulation. Despite potential life-threatening complications the patient made a good recovery and was discharged 3 weeks after surgery.

In 17 patients (eleven males, six females) with Morquio-Brailsford syndrome (mucopolysaccharidosis IV) we have used onlay femoral and tibial autografts placed posteriorly and secured to the laminae of C1 and C2 to obtain satisfactory occipito-C1/C2 posterior fusion. They were immobilised postoperatively in a halo-plaster body jacket for four months. The age at operation varied between three and 28 years. Those with myelopathic symptoms of recent onset made some recovery, but severely myelopathic patients showed little or no recovery. We advise prophylactic occipitocervical fusion in these patients since the cartilaginous dens is not strong enough to ensure atlanto-axial mechanical stability.

Costoplasty can reduce the important cosmetic deformity of rib prominence in scoliosis but there are few objective reports of correction. We recorded the results of three objective methods of assessing back shape before and after short-segment costoplasty in 55 patients. We showed that significant improvement was maintained over a two-year follow-up period. Primary costoplasty at the time of scoliosis surgery (n = 35) achieved greater proportional correction than secondary costoplasty performed after fusion of the spine (n = 20). The rib segments removed at primary surgery provided enough bone for the autogenous graft; harvesting from the pelvis was unnecessary. We report a new classification of rib morphology which helps in planning the site and extent of costoplasty, and in predicting the possible correction.

Four patients with osteogenesis imperfecta and neurologically significant basilar impression have been treated over the past 8 years. The experience has resulted in changes in our therapeutic strategy for this particularly difficult problem. These cases are discussed with respect to the disease process, neurological involvement, radiological findings, and modes of surgical therapy. The errors in management as well as the success resulting from our learning experience are described. Currently, we recommend the extensive removal of the anterior bony compression by a transoral approach. This should be followed by a posterior rigid fixation that transfers the weight of the head to the thoracic spine, in an effort to prevent further basilar invagination.

Summary We have studied the effects of the epidural administration of diamorphine 0.1 mg/kg at the L3–4 interspace on somatosensory evoked potentials in the cervical epidural space before corrective surgery for idiopathic adolescent scoliosis. A further eight patients in whom anaesthesia was maintained with a propofol infusion acted as a control group. Epidural diamorphine had no effect on the latency or amplitude of the evoked potentials. We conclude that epidural diamorphine is a suitable technique to use in scoliosis surgery because of its lack of effect on neurophysiological variables, although the potential respiratory problems need investigation.

We have evaluated the use of a synthetic porous ceramic (Triosite) as a substitute for bone graft in posterior spinal fusion for idiopathic scoliosis. In a prospective, randomised study 341 patients at five hospitals in the UK and France were randomly allocated either to autograft from the iliac crest or rib segments (171) or to receive Triosite blocks (170). All patients were assessed after operation and at 3, 6, 12 and 18 months. The two groups were similar with regard to all demographic and baseline variables, but the 184 treated in France (54%) had Cotrel-Dubouset instrumentation and the 157 treated in the UK usually had Harrington-Luque implants. In the Triosite group the average Cobb angle of the upper curve was 56 degrees, corrected to 24 degrees (57%). At 18 months, the average was 26 degrees (3% loss). In the autograft group the average preoperative upper curve of 53 degrees was corrected to 21 degrees (60%). At 18 months the mean curve was 25 degrees (8% loss). Pain levels after operation were similar in the two groups, being mild in most cases. In the Triosite group only three patients had problems of wound healing, but in the autograft group, 14 patients had delayed healing, infection or haematoma in the spinal wound. In addition, 15 autograft patients had pain at the donor site at three months. Seven had infections, two had haematoma and four had delayed healing. The haematological and serum biochemistry results showed no abnormal trends and no significant differences between the groups. There were no adverse events related to the graft material and no evidence of allergenicity. Our results suggest that Triosite synthetic porous ceramic is a safe and effective substitute for autograft in these patients. Histological findings on biopsy indicate that Triosite provides a favourable scaffolding for the formation of new bone and is gradually incorporated into the fusion mass.

STUDY DESIGN A retrospective study of 44 museum cases of spinal osteoid osteoma or osteoblastoma and a meta-analysis using 421 additional cases from a review of the literature. OBJECTIVES To identify the factors that are associated with the development of scoliosis in these patients. SUMMARY OF BACKGROUND DATA Painful scoliosis is a well recognized presentation of spinal osteoid osteoma and osteoblastoma and is considered to be secondary to pain-provoked muscle spasm on the side of the lesion. Previous studies have been based on small numbers of patients that did not permit statistical validation of the reported observations. METHODS Eight factors were assessed including: age, gender, duration of symptoms, site of lesion in the spine, vertebral level of lesion, site of lesion in the individual vertebra, type of lesion, and Cobb angle at presentation. Reports were reviewed only if the presence or absence of scoliosis could be determined. Statistical analyses initially were performed on the museum cases and then on a combination of museum cases and cases from the literature. RESULTS Overall, 63% of subjects had scoliosis. The lesions were typically present on the concave aspect of the curve. Three cases of scoliosis from the literature involved lesions that were reported to be on the convexity. Scoliosis is significantly more common in cases of osteoid osteoma than in cases of osteoblastoma (P < 0.0001); lesions are more common in the thoracic and lumbar regions than in the cervical region (P < 0.0001), in lower cervical region than in the upper cervical region (P value = 0.0027), and they are more commonly located to one side of the midline (P < 0.0001). Age, gender, and duration of symptoms were of no significance. CONCLUSIONS The findings support the concept that scoliosis is secondary to asymmetric muscle spasm in patients with spinal osteoid osteoma or osteoblastoma.

Of the various techniques for monitoring spinal cord function during surgery, that of recording spinal somatosensory evoked potentials (SEPs) from the epidural space following electrical stimulation of peripheral nerves is often preferred to less invasive methods (Jones et al., 1982, 1983; Macon and Poletti, 1982; Macon et al., 1982; Bradshaw et al., 1984; Beric et al., 1986; Nainzadeh et al., 1986; Schramm et al., 1986; Whittle et al., 1986; see Dinner et al., 1986 for review). In order fully to appreciate the significance of changes occurring during surgery we need to understand in detail the physiological characteristics of the potentials recorded, including which sensory modalities and spinal cord tracts are represented.

Objective. To illustrate the variety of paravertebral muscle abnormalities as seen on computed tomography (CT) or magnetic resonance imaging (MRI) in association with spinal osteoblastomas and correlate the findings with the presence of scoliosis. Design. In a retrospective study the clinical notes, plain radiographic, CT and/or MRI features were reviewed for the presence of scoliosis and paravertebral muscle abnormality (either inflammation or atrophy). Patients. Twelve patients (7 male, 5 female) with a mean age of 17 years were studied. Three lesions occurred in the cervical spine, five in the thoracic spine and four in the lumbar spine. Results and conclusions. Nine patients had scoliosis. All patients with a thoracic or lumbar lesion and scoliosis (n=8) had an associated abnormality of the paravertebral muscles (usually atrophy with fatty replacement). One patient with a lumbar lesion and no scoliosis had normal paravertebral muscles. One patient with a cervical lesion had thoracic scoliosis but no muscle abnormality in the cervical region, while two patients with cervical lesions and no scoliosis showed muscle abnormalities. The results support the clinical hypothesis that scoliosis in patients with spinal osteoblastoma is due to paravertebral muscle spasm, although this would not appear to be the case for cervical lesions.

In 17 patients (eleven males, six females) with Morquio-Brailsford syndrome (mucopolysaccharidosis IV) we have used onlay femoral and tibial autografts placed posteriorly and secured to the laminae of C1 and C2 to obtain satisfactory occipito-C1/C2 posterior fusion. They were immobilised postoperatively in a halo-plaster body jacket for four months. The age at operation varied between three and 28 years. Those with myelopathic symptoms of recent onset made some recovery, but severely myelopathic patients showed little or no recovery. We advise prophylactic occipitocervical fusion in these patients since the cartilaginous dens is not strong enough to ensure atlanto-axial mechanical stability.

It is widely believed that brain stem dysfunction and cranial nerve palsies in patients with rheumatoid arthritis (RA) are common and related to the vertical translocation of the odontoid process. In our database of 235 patients with seropositive RA and craniocervical junction involvement, we have found a very low incidence of such problems. Long tract signs were common, but loss of proprioception (joint position sensation) as the sole neurologic deficit was rare. Nystagmus was found to be associated with the tonsillar herniation of a Chiari 1 malformation and loss of joint position sensation with severe compression of the posterior aspect of the spinal cord at the craniocervical junction. The implications for posterior occipitocervical fusion, particularly by sublaminar wiring, are discussed.

A 3.5 year old boy with Morquio's disease was referred with a persisting left hemiparesis four months after a fall and was found to have craniocervical junction compression due to atlantoaxial subluxation and significant anterior soft tissue compression. Transient unconsciousness at the time of the fall was probably due to medullary concussion as a result of hyperextension, not a head injury. Spinal cord compression due to atlantoaxial subluxation at the craniovertebral junction is a major cause of disability and death in these patients. Once cervical myelopathy appears, early posterior occipitocervical fusion has been advocated in order to arrest the progression of neurological disability and this is successful in most cases. This conventional approach was considered unsafe because of the significant anterior compression. A combined anterior transoral decompression with posterior fusion to deal with this particularly difficult problem is described.

Since 1981, during operations for spinal deformity, we have routinely used electrophysiological monitoring of the spinal cord by the epidural measurement of somatosensory evoked potentials (SEPs) in response to stimulation of the posterior tibial nerve. We present the results in 1168 consecutive cases. Decreases in SEP amplitude of more than 50% occurred in 119 patients, of whom 32 had clinically detectable neurological changes postoperatively. In 35 cases the SEP amplitude was rapidly restored, either spontaneously or by repositioning of the recording electrode; they had no postoperative neurological changes. One patient had delayed onset of postoperative symptoms referrable to nerve root lesions without evidence of spinal cord involvement, but there were no false negative cases of intra-operative spinal cord damage. In 52 patients persistent, significant, SEP changes were noted without clinically detectable neurological sequelae. None of the many cases which showed falls in SEP amplitude of less than 50% experienced neurological problems. Neuromuscular scoliosis, the use of sublaminar wires, the magnitude of SEP decrement, and a limited or absent intra-operative recovery of SEP amplitude were identified as factors which increased the risk of postoperative neurological deficit.

Spinal somatosensory evoked potentials were recorded in 35 neurologically normal patients undergoing surgery for scoliosis. The recording electrodes were placed in the dorsal epidural space. Stimulation was of the tibial nerve in the popliteal fossa and the posterior tibial and sural nerves at the ankle. At thoracic levels the response consisted of at least 3 components with different peripheral excitation thresholds and spinal conduction velocities (range 35-85 m/sec). All components were conducted mainly in tracts ipsilateral to the stimulus, component 1 being most laterally located. At low stimulus intensity only the fastest activity was recorded but higher intensities elicited additional, slower conducting components. Component 1 was much less prominent when the posterior tibial nerve was stimulated at the ankle and absent from the (cutaneous) sural nerve response. Component 1 is likely to be due to the stimulation of group 1 muscle afferents which terminate in the dorsal horn and activate second-order neurones, many of whose axons go to form the ipsilateral dorsal spinocerebellar tract. Components 2 and 3 are believed to be largely cutaneous in origin and to be conducted mainly in the dorsal columns.

Spinal somatosensory evoked potentials were recorded in 35 neurologically normal patients undergoing surgery for scoliosis. The recording electrodes were placed in the dorsal epidural space. Stimulation was of the tibial nerve in the popliteal fossa and the posterior tibial and sural nerves at the ankle. At thoracic levels the response consisted of at least 3 components with different peripheral excitation thresholds and spinal conduction velocities (range 35-85 m/sec). All components were conducted mainly in tracts ipsilateral to the stimulus, component 1 being most laterally located. At low stimulus intensity only the fastest activity was recorded but higher intensities elicited additional, slower conducting components. Component 1 was much less prominent when the posterior tibial nerve was stimulated at the ankle and absent from the (cutaneous) sural nerve response. Component 1 is likely to be due to the stimulation of group 1 muscle afferents which terminate in the dorsal horn and activate second-order neurones, many of whose axons go to form the ipsilateral dorsal spinocerebellar tract. Components 2 and 3 are believed to be largely cutaneous in origin and to be conducted mainly in the dorsal columns.

The theme of this chapter is the prevention of spinal instability and deformity secondary to trauma, surgery and diseases of the spine. The treatment of established scoliosis and/or kyphosis is not within its remit. The bony and ligamentous damage consequent on trauma can produce deformity in later years. It comes as a shock to some clinicians that wide surgical destruction of the supportive elements of the vertebral column will also have the same effect. In part, this attitude has been engendered by the short survival prospects of many malignant “spinal” patients. A sequential approach has been adopted on the grounds that if the patient survived long enough, secondary corrective surgery might be considered. The problems of course are complex; maximum exposure for neurosurgery will mean almost certain spinal instability and/or deformity. Despite improved surgical awareness, there are far too many occasions when a simple laminectomy in an adult is undertaken in such a way that the pars interarticularis is knowingly or unknowingly fractured with the consequential risk of segmental instability. A more devasting error is widespread excisive laminectomy for spinal tumour in the immature skeleton without any consideration of the effects of the bony destruction on longitudinal spinal growth.

Sir, I read with interest the paper by Joslin, Khan and Bannister[1][1] in the September 2004 issue entitled ‘Long-term disability’. The Bristol group has previously pointed out how poor the modern treatment of supervised neglect, combined with analgesia, physiotherapy, chiropractic and

Cervical myelopathy is a rare but potentially dangerous complication of rheumatoid arthritis and presents considerable therapeutic problems. A conservative approach carries high mortality and surgical intervention is not without serious risks. Reduction of subluxation and posterior fusion is widely practised but may require prolonged bed rest and continuous skull traction, sometimes for many weeks. When anterior decompression has been attempted prolonged immobilisation and external fixation have created problems. In this series 23 rheumatoid patients with cervical myelopathy were investigated over a four-year period. Seventeen underwent anterior decompression of the cervical cord, of whom 14 had a transoral removal of the odontoid peg and pannus and posterior occipitocervical fusion during the same anaesthetic without mortality or serious postoperative complications; all but one have improved. The authors believe that early mobilisation after a combined cord decompression and internal fixation has reduced the mortality and morbidity. Management of cervical myelopathy in rheumatoid arthritis and indications for operation are discussed.

A survey has been undertaken of the various complications of halo-pelvic distraction in 118 patients with scoliosis prior to spinal fusion. In the first sixty-two patients the standard solid distraction rods were employed. The neurological complications included ten cases of cranial nerve lesions and two cases of paraplegia, one of them permanent. Springs were then incorporated in the distraction rods so as to allow direct readings ofthe distraction forces, and a total force of 18 kilograms was not exceeded in the last fifty-six patients. No further serious neurological complications occurred, but the amount of correction achieved in the adolescent and juvenile idiopathic types of scoliosis was reduced.

An electrophysiological system for monitoring the spinal cord during operations for scoliosis is described. During the development of the technique the recording of cortical somatosensory evoked potentials from the scalp and spinal somatosensory evoked potentials from the laminae or spines was superseded by the positioning of recording electrodes in the epidural space cephalad to the area to be fused. All recordings were made in response to stimulation of the posterior tibial nerve at the knee. Results in 138 patients are presented and the findings in three patients who exhibited neurological deficits after operation are described. It is concluded that spinal somatosensory evoked potentials are sensitive to minor spinal cord impairment, possible due to ischaemia, and that these changes may be reversed when the cause is quickly remedied. The monitoring system interferes minimally with anaesthetic and surgical procedures and is now performed as a routine.

A study was undertaken to evaluate the possibility of using the pain drawing of a patient with low-back pain as a screening test to determine whether further psychologic evaluation was necessary. Using the analysis described, the pain drawing predicted a high or low hypochondriasis or hysteria scale

Five cases of hydatid disease affecting the vertebrae are described. Clinical features, radiologic appearance, and poor prognosis are emphasized. Four patients had some degree of neurologic deficit at the time of presentation and in three cases there was an increasing kyphosis. In two patients, spinal instrumentation with Harrington apparatus supplemented removal of hydatid material, and its use improved the previous neurologic deficit with stabilization of kyphosis. The antihelmintic drug mebendazole was used in two cases.

1. French in 1946 presented eight cases of arachnoiditis complicating a lumbar disc lesion; five further cases are reported here. 2. It is suggested that repeated minor persistent trauma produces the strictly localised changes in the arachnoid, in the same sort of way that it may produce ulnar neuritis at the elbow. 3. The various causes of arachnoiditis are discussed. 4. The place of operation has been found difficult to assess.

A survey has been undertaken of the various complications of halo-pelvic distraction in 118 patients with scoliosis prior to spinal fusion. In the first sixty-two patients the standard solid distraction rods were employed. The neurological complications included ten cases of cranial nerve lesions and two cases of paraplegia, one of them permanent. Springs were then incorporated in the distraction rods so as to allow direct readings of the distraction forces, and a total force of 18 kilograms was not exceeded in the last fifty-six patients. No further serious neurological complications occurred, but the amount of correction achieved in the adolescent and juvenile idiopathic types of scoliosis was reduced.

Cervical myelopathy is an uncommon but potentially fatal complication of rheumatoid atlanto-axial subluxation. Computerised myelotomography with three-dimensional reconstruction shows that rheumatoid pannus, together with the odontoid peg, contributes significantly to anterior cervico-medullary compression. These findings were the basis for treatment by transoral anterior decompression and posterior occipitocervical fusion, which removes both bony and soft-tissue causes of compression and allows early mobilisation without major external fixation. We report encouraging results from this combined approach in 14 patients who had progressive neurological deterioration.

This account describes a retrospective analysis of epidural spinal cord monitoring results in 410 patients undergoing posterior fusion and instrumentation for scoliosis. None developed serious neurological complications postoperatively but 9 (2.2%) showed mild defects. Out of 24 in whom the monitor indicated a transient or sustained conduction impairment (> 60% amplitude reduction) 6 had problems postoperatively, representing a minimal correct detection rate of 1.5% and a maximal false positive rate of 4.4%. Of the 3 remaining cases, no potentials could be recorded from the appropriate limb(s) at any time in 2 who experienced mild neurological exacerbation due to root or cord lesions, and one patient in whom monitoring was uneventful developed signs of a lumbo-sacral root lesion.

Rigid posterior fixation of the skull to the third, fourth and fifth cervical vertebrae was achieved in three patients who, as a result of operation, had gross instability of the craniocervical junction. An anatomically contoured steel loop was secured to the occiput via small burr holes and to the vertebrae by sublaminar wiring. This technique has the advantage over bone grafting, either alone or with cement, in that it affords rigid stabilisation, allows early mobilisation and may contribute to eventual bony fusion.