A TECHNIQUE OF CORRECTION AND INTERNAL FIXATION SCOLIOSIS

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1 A TECHNIQUE OF CORRECTION AND INTERNAL FIXATION FOR SCOLIOSIS J. RESINA, LISBON, and A. FERREIRA ALVES, OPORTO, PORTUGAL From the Sanat#{243}rio do Outdo, Lisbon and the ClInica Ortop#{233}dica Heli#{226}ntia, Oporto This report describes a technique for the correction and fusion of scoliosis with the aid of a flexible metal rod that is fixed by wires under tension to the bases of the spinous processes on the convex side of the curve at a number of points. The results in a series of 100 cases are reported. In the last seventy patients, the average correction at one month was 51 per cent, and after two years 45 per cent. In these seventy cases the incidence of pseudarthrosis was 5-7 per cent. Scoliosis continues to be one ofthe greatest problems in the field of orthopaedic therapeutics despite remarkable progress made in the last few decades. A landmark was the introduction oftechniques ofinternal instrumentation (Marino-Zuco 1954 ; Allan 1955 ; Gruca 1958 ; Dwyer and Schafer 1974), especially that of Harrington (1960, 1962) using a distraction rod on the concave side of the curve. Pursuing these ideas, one of us (J.R.) developed an original technique for internal reduction and fusion (Resina 1963). Some years later, the new technique meanwhile having proved its value, another surgeon (A.F.A.) independently confirmed the previous results. The results obtained by both authors are therefore being given here together. The method is based on the principle of straightening the bent trunk ofa tree with the aid ofa stake bound to it. In short, a flexible metal rod is attached to the base of a number of spinous processes on the convex side of the curve by horizontal wires under tension. The resistance offered by the rod tends to reduce the curve as the fixation is progressively being made. The rod is firstly an aid to reduction, and secondarily a means of internal fixation to aid spinal fusion. From the mechanical point of view, it is plain that in order to reduce a curve in this way, the corrective forces must work at right angles to the long axis of the metal rod. On the other hand, the metal rod, being inside the fusion zone, acts like a rigid structure, reinforcing and holding it as in the case of reinforced concrete. TECHNIQUE The equipment required is quite simple (Fig. 1). Round stainless steel rods-the rod is the basic element and must have a good coefficient of elasticity. Two sets of rods are used ; each varies in length from 15 to 30 centimetres by steps of 1 centimetre. The diameter of the rods of one set is 4 millimetres and of the other 45 millimetres. In order to avoid longitudinal migration the ends of the rod are split and opened out like the tail of a fish. The variation of length and thickness allows for the choice of a rod according to the length of the curve, the rigidity of the spine and the strength of the spinous processes. Stainless steel wire-wire ranging in diameter from 1 to 1-2 millimetres (20 to 28 S.W.G.) is cut in lengths of 15 to 20 centimetres. Recently we have been using a special clip which is closed by modified universal pliers. A right-angled aw/-this is used to perforate the base of each spinous process. A wire twister-any suitable kind of appliance can be used. Surgical technique-the vertebrae are approached subperiosteally on both sides, giving a wide exposure of the laminae and transverse processes of all the vertebrae to be fixed. In the case of a severe curve the ligamentous structures are released from the transverse processes on the concave side. Decortication of the articular processes by the technique of Moe (1958) makes correction of the curve easier. Each spinous process is perforated transversely through the middle of its base in the area of strong cortex found at its junction with the lamina. Through each hole a wire is introduced and held by a Doyen forceps. The rod is now placed on the convex side and fixed by wire to every spinous process from the first or second vertebra above the uppermost one of the curve as far down as the apical vertebra. These first points of fixation serve to distribute the tensions involved in reduction of the curve and allow this to proceed with greater security. An assistant using the compression-conductor (Fig. 1) then presses the rod against the base of the spinous process of the first or second vertebra below the lowermost one of the curve, while external manoeuvres help to reduce the curve and bring that process nearer to the rod. When contact is made the rod is provisionally fixed to these lower processes by one or two strong Maseaux forceps. Fixation of all the processes below the apex is then accomplished. A final, careful, progressive torsion of all the wires completes the fixation and brings the rod into close contact with the base of each spinous process. In this way the rod of course comes under considerable strain and by virtue of its elasticity acts continuously upon the scoliotic curve. When it is foreseen that the rod will be under great strain, or when the processes are fragile, it is advisable to reinforce the fixations (Fig. 2). We must emphasise the importance of the technique details of reinforcement because loosening of the rod at the upper end of a thoracic curve was one of the main troubles in the experimental phase of the method. More recently, in cases where fixation of the tip of the rod seemed doubtful, this. has been reinforced by acrylic cement cooled with normal saline. Dr Jacques Resina, Director do Sanat#{243}rio Ortopedico de Out#{227}o, Setubal, Portugal. Dr Alvaro Ferreira Alves, Director da Clinica Ortopedica Heli#{227}ntia, Valadares, Oporto, Portugal. VOL. 59-B, No. 2, MAY

2 160 J. RESINA AND A. FERREIRA ALVES The instrumentation : 1-a stainless steel rod; 2-stainless steel wires; 3-special clips; 4-bone-holding forceps, Lewin s type; 5-a right-angled awl; 6-a wire twister ; 7-twisting forceps ; 8-a compressor-guide ; 9-Museux s uterine forceps; 10-Circlip pliers ; and 11-universal pliers with a slot in each jaw for the clips. After these basic steps of reduction and fixation, posterior spinal fusion is performed by well-known techniques. Special care is taken with fusion of the articular processes (Moe 1958) and with bilateral decortication of all the surfaces of the transverse processes and laminae. Autogenous iliac bone grafts are applied to the whole extent of the curve, but mainly on the concave side. Special attention is paid to making a first layer of small medullary chips and a second layer of cortical bone cut into small sticks and pressed well home. Sometimes it is necessary to take iliac bone from both sides. Suction drainage is applied before closure. Post-operative management-the patient is nursed in a recumbent position, mainly supine, or in a bed cast. The suction drainage is maintained for twenty-four to seventy-two hours. After two or three weeks a Risser cast is applied, with or without compression according to the rib hump deformity. If halo traction has been used, it is retained until the application of the cast. Our practice has been to advise prolonged rest in bed for four to six months according to the aetiology of the curve and the severity of the case. After this period the Risser cast may be replaced and the patient allowed up. In a difficult case, when the cast is removed after eight to twelve months, continued protection is given by a Milwaukee brace or a simple body cast. RESULTS From 1962 to 1972, 100 patients were operated on in our two departments. Sixty-three were female and thirtyseven male. Fifty-six were aged ten to fourteen years, and thirty-one were between fifteen and twenty years. The remaining thirteen patients were under ten years of age and were operated on because of rapidly increasing curvature. Idiopathic scoliosis (seventy-five cases) was the most frequent variety, followed by poliomyelitis (fifteen) and congenital scoliosis (six). In order to evaluate the new method, we have paid special attention to the early post-operative correction, which best illustrates its possibilities. A summary of the findings at one month in the whole series of 100 cases evaluated by the Cobb technique is given in Table I. The amount of correction largely depended on the degree of the initial curve, as shown in Table II. As regards aetiology, the best corrections were obtained in the fifteen cases of poliomyelitis and in a single case of the Ehiers-Danlos syndrome (Table III). With regard to the results after two years, the initial series of thirty cases in the experimental phase has not been taken into account because of several late complications due to faults in technique. The later results in seventy cases treated by the present improved technique are given in Table IV. The average correction at two years was 295 degrees or 45 per cent. As can be seen from Table IV, the best results were related to the degree of mobility of the curve, being obtained from less marked curves in younger patients with less structural change, and in cases the aetiology of which favours mobility. THE JOURNAL OF BONE AND JOINT SURGERY

3 A TECHNIQUE OF CORRECTION AND INTERNAL FIXATION FOR SCOLIOSIS 161 Tan AVERAGE CORRECTION AT ONE MONTH IN 100 PATIErrrs I Average initial curvature (range 40 to 140 degrees) 685 degrees Average curvature one month after operation. 35 degrees Average correction degrees (49 per cent) Maximum 76 degrees (78 per cent) Minimum 10 degrees (16 per cent) II THE CORRECTION AT ONE Mor,nii IN RELATION TO THE INITIAL CURVE Number Initial curvatures Average curvature Before operation After operation Average correction to (57 per cent) to (485 percent) I 3 76 to (43 per cent) to (41 per cent) THE CORRECTION AT ONE MONTH IN ScoLlosls OF DIFFERENT AETIOLOGIES III Number Aetiology Average (years) age Average curvature Before After Average correction 20 Infantile idiopathic 31 Juvenile idiopathic 24 Adolescent idiopathic 10 (4 to 16) 12 (6 to 16) 15 (12 to 21) (44 per cent) (50 percent) (51 percent) I 5 Paralytic 1 1 (7 to 14) 6 Congenital 1 1 (7 to 15) 2 Neurofibromatosis 15 (13 and 17) (52 per cent) (26 per cent) (38 per cent) I Myopathic (40 per cent) I Ehlers-Danlos syndrome (71 per cent) THE RESULTS IN SEVENTY CONSECUTIVE PATIENTS AFTER Two YEARS OR Mont IV Number of patients Average curvature Average correction Preoperative Postoperative T Present Initial Present (51 per cent) 295 (45 per cent) Average loss 4 (6 per cent) Range 38to140 Range I Range 16to76 11to76 VOL. 59-B, No. 2, MAY 1977

-I 162 J. RESINA AND A. FERREIRA ALVES IN FIG.

Centre-Showing the application of the wire or clips.

of reinforcement by wire under the lamina or round the opposite

Complications In the whole series of 100 consecutive cases there

to graft contamination in the bone bank.

4 -I 162 J. RESINA AND A. FERREIRA ALVES IN FIG. 2 Above-To show techniques of perforation. Centre-Showing the application of the wire or clips. Below-Showing fixation of the rod by wire or clip, and two patterns of reinforcement by wire under the lamina or round the opposite transverse process. Complications In the whole series of 100 consecutive cases there were no deaths, no neurological complications and no pulmonary lesions. Moderate operative shock was observed in two cases but was easily overcome. Wound infection complicated three cases, two of them being ascribed to graft contamination in the bone bank. In the first thirty cases loosening and migration of the rod were the most frequent cause of trouble. At first the problem was dealt with by attaching a nut to each end of the rod (Fig. 5), but later by the simple measure of splitting the ends and spreading them into the shape of a fish tail. Sometimes the end of the rod became free due to rupture of the wire or to bone erosion at the points of fixation to the spinous processes. This was often seen in the initial series of fifteen cases, but became infrequent when thicker wires, better supplementary fixation (Fig. 2), THE JOURNAL OF BONE AND JOINT SURGERY

5 A TECHNIQUE OF CORRECTION AND INTERNAL FIXATION FOR SCOLIOSIS 163 Case 2-..owing the correction of another...j-thoracic scoliosis. VOL. 59-B, No. 2, MAY 1977

Note the additional fixation of the upper end of the rod by wire round the opposite

6 164 J. RESINA AND A. FERREIRA ALVES 2: E FIG. 5 Case 3-Showing the correction of an idiopathic high thoracic scoliosis. Note the additional fixation of the upper end of the rod by wire round the opposite transverse process. FIG. 6 Case 4-Showing the correction of an idiopathic thoraco-lumbar scoliosis. THE JOURNAL OF BONE AND JOINT SURGERY

7 A TECHNIQUE OF CORRECTION AND INTERNAL FIXATION FOR SCOLIOSIS I 65 and a Risser cast in the second or third week were used. Fracture of the rod also occurred in two cases in which stainless steel was not used, probably from metal fatigue at the level of a pseudarthrosis. Because of these troubles during the experimental phase, the number of pseudarthroses-ten out of thirty-was very considerable, eight being due to poor fixation or migration or fracture of the rod. Among the last seventy cases however, there were only four pseudarthroses, two probably due to the use of grafts from the bone bank and the remaining two to imperfect fixation of the rod. ILLUSTRATIVE CASE REPORTS Four cases demonstrate the possibility of the method. No previous correction having been attempted, the results are in fact the consequence solely of reduction by the new technique. Case 1-A girl aged thirteen had an idiopathic mid-thoracic scoliosis of 19 degrees at the age of nine, 30 degrees at ten, 40 degrees at twelve and finally 73 degrees (Fig. 3). The immediate correction after operation was 51 degrees (70 per cent). Three years later 10 degrees of correction had been lost, without pseudarthrosis. The rib hump was much reduced and the cosmetic result was good. Case 2-A girl of sixteen had an idiopathic mid-thoracic scoliosis first noticed at the age of ten and progressing rapidly to reach 106 degrees (Fig. 4). In spite of marked rigidity of the curve, it was possible to achieve a reduction of 52 degrees (49 per cent). Four years later the aesthetic improvement had been maintained. We now employ halo-femoral traction before operation for such a case. Case 3-A girl aged sixteen had an idiopathic high thoracic scoliosis of 65 degrees (Fig. 5). The immediate correction was 35 degrees (54 per cent), and eight years later 28 degrees (43 per cent). This case demonstrates the possibilities of the method applied to a high thoracic curve, always a difficult problem. Case 4-A girl of twelve had an idiopathic thoraco-lumbar scoliosis of 66 degrees (Fig. 6). The immediate correction was 44 degrees (67 per cent). There was an early loss of 4 degrees from a pseudarthrosis which healed spontaneously, and two years later the residual correction was fully maintained. This case illustrates the action of the supporting rod, with very good correction of the imbalance of the trunk. DISCUSSION The results obtained in this series show that the technique permits a considerable reduction of scoliosis with little operative and post-operative danger. The technique is relatively simple, and though it naturally demands a basic knowledge of the treatment of scoliosis, does not require a highly trained team. At first sight it may seem that the bases of the spinous processes are not strong enough to oppose the stresses of reduction. Actually, because the fixation of the rod is made at a number ofpoints, these stresses are well distributed, a fact which is an essential feature of the technique. We believe that the method partially corrects rotation by virtue of the corrective stresses and their relationship to the axis of vertebral rotation. Both observations at operation and later on radiographs have shown that when a certain degree of mobility of the curve was still present, partial correction of rotation was obtained in some cases. We have also repeatedly noticed, during the application of the method, that the kyphotic element was reduced. In pronounced structural curves the supporting rod per se is not sufficient to obtain a good result and may be difficult or even dangerous to apply. In such cases we now use the modern methods of progressive distraction and find that the supporting rod and its ties improve the correction already obtained. Rod fixation requires some rigidity of cortical bone, which is not always adequate, but this drawback may be overcome by additional fixation. The tendency to erosion at the points of perforation of the spinous processes, although lessened by their numbers, cannot be entirely avoided, a fact which makes the protection of a cast necessary. The presence of the rod would seem to favour sound consolidation of the grafts, which may well be the reason for the low average loss of correctiononly 4 degrees or 6 per cent after two years.. REFERENCES Allan, F. G. (1955) Scoliosis : operative correction of fixed curves. Journal of Bone and Joint Surgery, 37-B, Dwyer, A. F., and Schafer, M. F. (1974) Anterior approach to scoliosis. Journal ofbone and Joint Surgery, 56-B, Gruca. A. (1958) The pathogenesis and treatment of idiopathic scoliosis. Journal of Bone and Joint Surgery, 40-A, Harrington, P. R. (1960) Surgical instrumentation for management of scoliosis. Journal ofbone and Joint Surgery, 42-A, Harrington, P. R. (1962) Treatment of scoliosis. Journal ofbone andloint Surgery, 44-A , 634. James, J. I. P. (1955) Kyphoscoliosis. Journal of Bone and Joint Surgery, 37-B, Marino-Zuco, C. (1954) Scoliose. In Sixi#{232}meCongres International de Chirurgie Orthop#{233}dique, Berne. Pp Bruxelles: Imprimerie Lielens, Moe, J. H. (1958) A critical analysis of methods of fusion for scoliosis. Journal ofbone andjoint Surgery, 40-A, Resina, J. (1963) Redressement Ct stabilisation immediate des scolioses par un tuteur m#{233}tallique. Association Europ#{233}ene contre la Poliomyelite. IX Symposium, Stockholm, 1-4 September Pp Paris: Masson et Cie. VOL. 59-B, No. 2, MAY 1977

Idiopathic scoliosis Scoliosis Deformities I 06

Idiopathic scoliosis Scoliosis Deformities I 06 What is Idiopathic scoliosis? 80-90% of all scolioses are idiopathic, the rest are neuromuscular or congenital scolioses with manifest primary diseases responsible for the scoliotic pathogenesis. This