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POSTERIOR SPINAL FUSION IN SOTOS' SYNDROME
British Journal of Anaesthesia 1991; 66: 728-732
POSTERIOR SPINAL FUSION IN SOTOS' SYNDROME D. SURESH Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
There was no family history of Sotos' syndrome. Manifest features included growth patSotos' syndrome (synonym: cerebral gigantism) tern, hypertelorism and palpebral fissures, progis the association of mental retardation, macro - nathism, receding hairline and large spadelike cephaly and prenatal onset of accelerated hands with a single palmar crease on the right. growth. The rapid skeletal growth may account Pubertal development was nearly complete, with for a 4% incidence of scoliosis. General an- small external genitalia and scanty pubic hair, but aesthesia using halothane or enflurane in nitrous no pigmentation [3]. He had a clumsy gait, and oxide and oxygen, with opioid supplementation showed psychomotor retardation. He could be and labetalol to induce moderate hypotension, difficult and stubborn and only his parents were appeared to be a satisfactory technique for able to influence his behaviour, although intelcorrective spinal surgery. The potential problems lectually he was not as impaired as he appeared. The main musculo-skeletal features were are discussed, with mental retardation and sometimes aggressive behaviour contraindicating a accelerated linear growth and skeletal maturation. "wake-up" test. Extradural somatosensory Kyphoscoliosis was obvious from the age of 4 yr, evoked potential monitoring is a satisfactory with some pelvic instability. When he was 11 yr, alternative. Hook failures seem more likely than a right thoracic scoliosis was treated with a brace in patients undergoing surgery for adolescent for 8 months. An x-ray examination in and out of the brace showed a 48° right thoracic curve at the idiopathic scoliosis. T4-10 level, and a 52° left lumbar curve between T i l and L4. When he was admitted for correction KEY WORDS of his scoliosis, this had deteriorated to a 70° right Anaesthesia: general. Complications: Sotos' syndrome. and a 70° left lumbar scoliosis, represting a 20° Surgery: spinal fusion. deterioration over the previous 10 months. At the age of 14 yr, the subject weighed 90 kg, Sotos' syndrome (synonym: cerebral gigantism) his height was 170 cm and his arm span measured is the association of mental retardation, macro- 178 cm. Cardiovascular and neurological assesscephaly and prenatal onset of accelerated growth ment were unremarkable. Lung function tests inherited as an autosomal dominant trait [1]. Bone revealed a restrictive defect with a forced vital age is advanced in all children, and although capacity (FVC) of 1.7 litre (32% of predicted scoliosis is not part of the syndrome complex, norm). A glucose tolerance test and anterior rapid skeletal growth may account for a 4% pituitary functions were normal and a lateral incidence as reported in one series [2]. Patients radiograph of the skull showed a normal pituitary may therefore present for surgical correction of fossa. Routine haematology and biochemistry their scoliosis. screens were within normal limits, as were serum concentrations of 17-OH progesterone, calcium, CASE REPORT phosphate and alkaline phosphatase. He snored A male child was delivered by forceps at 42 weeks following an uncomplicated pregnancy; he weighed 4.2 kg at birth. He suffered from "jerks" D. SURESH, F.F.A.R.C.S.I., Anaesthetics Unit, The Royal London Hospital, Whitechapel, London El IBB. Present which ceased at age 1 yr, and his early motor, address: Department of Anesthesiology, Duke University speech and language development was reported Medical Center, Durham, NC 27710, U.S.A. Accepted for also to be delayed. Publication: January 7, 1991. SUMMARY
SPINAL FUSION IN SOTOS' SYNDROME
729
and had been investigated recently for sleep apnoea, the results of which were reported as negative. There were recent behavioural problems and his behavioural age was estimated to be about 6 yr.
months, lasted 6 h 15 min. The patient was awake a few minutes after antagonism of neuromuscular block, when clinical testing allowed confirmation of intact neurological function as indicated by the continuous intraoperative somatosensory evoked potential (SEP) monitoring.
Anaesthesia
Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
Because the patient hated needles, premedication consisted of diazepam 10 mg orally. Both Postoperative course parents were present during induction of anThere was a slight ooze from the wound and aesthesia, which would have been impossible perioperative blood loss totalled 3250 ml. There without their calming influence. The facemask was a short episode of unexplained suprawas held by the father for induction of sleep with ventricular tachycardia which settled later to halothane in oxygen. Vecuronium 10 mg was about 120 beat min"1. An infusion of papaveretum given to facilitate intubation with a 9.0-mm cuffed 4 mg h"1 provided satisfactory analgesia. He reorotracheal tube, with additional intermittent ceived assisted positive pressure ventilation with a doses to facilitate IPPV. Anaesthesia was main- Bird ventilator according to a standard procedure tained with 1-2% halothane and 65% nitrous —initially hourly until his FVC was 25 % of best oxide in oxygen. A radial artery cannula and a preoperative value, then 2 hourly until FVC was right internal jugular cannula were inserted. The 50%, and thereafter 4 hourly until 75% of the patient was placed prone on a Montreal mattress baseline values had been attained [5]. and the extradural space at C7-T1 was located The boy made satisfactory progress until 2 using the "hanging drop" technique with a 16- weeks later, when an erect radiograph of the spine gauge Tuohy needle [4]. A 3-French gauge bipolar revealed that the top hook at T4 had cut out and recording electrode was positioned in the extra- approximately 20° correction had been lost. He dural space and connected to a Medelec MS 91 was prepared for surgery on the following day. electomyograph recorder. The right and left This time there was less objection to both i.m. posterior tibial nerves were stimulated alternately premedication and i.v. induction with thiopenvia skin surface electrodes using a square wave tone. The trachea was intubated using suxaimpulse of 0.2 ms duration at an intensity of methonium and IPPV was facilitated by a single 150 uV. The stimulation frequency was 20 s"1 and bolus of vecuronium 5 mg. Anaesthesia was 1000 responses were averaged with a resolution of maintained with enflurane and nitrous oxide in 0.33 ms and with the filters set at 200 Hz to oxygen and intermittent doses of papaveretum 2 KHz. provided analgesia. Labetalol (total 40 mg) was used again for hypotension to systolic values Intermittent doses of pethidine were given to supplement anaesthesia, and hypotension to sys- similar to those in the first operation. SEP tolic pressures of about 70 mm Hg was achieved monitoring was uncomplicated and re-fixation of with labetalol (total 85 mg). As the quality of the upper rod was completed uneventfully and traces from the spinal cord monitoring was poor, with minimal blood loss. A urinary catheter was a distal electrode was inserted at Ll-2 and this not inserted on this 1occasion. As before, tachyprovided good traces between this and the cardia (140 beat min" ) and a transient pyrexia of stimulating electrode, but not superiorly. An 39 °C were noted on the first day after operation. additional electrode was sited therefore at the Six days later, several episodes of frank painless T3—4 interspace; this resulted eventually in haematuria occurred, the cause for which resatisfactory recordings from the posterior tibial mained unexplained despite exhaustive investignerves. The operative procedure consisted of ations. This settled as spontaneously as it began internal fixation of a contoured Harrington rod, and allowed discharge from hospital the following stabilized at each level with Luque sublaminal week. wiring. Intraoperative fluid replacement included When reviewed 1 month later, radiography crystalloid 1000 ml, colloid 2000 ml and 3 units of revealed that the lower hook at Tl2 had dislodged. plasma reduced blood. Fortunately, the multilevel sublaminal wire fixThe procedure, including customizing a sub- ation reinforced by the plaster cast maintained a ortholene plaster cast prescribed for the next 8 reasonable correction for the thoracic curve and
BRITISH JOURNAL OF ANAESTHESIA
730
the patient was advised to remain in plaster for 8 months.
A 13:20 L 15.72 ms
Control
R 15.96 ms
B 13:35 L 15.60 ms
Wiring
R 15.72 ms
C 14:25
L 15.84 ms
Distraction
R 15.84 ms
D 14:35
L 15.84 ms
After distraction
R 15.96 ms
DISCUSSION
0.4
3 ms
FIG. 1. Sample extradural SEP recordings in response to alternate right and left posterior tibial nerve stimulation from electrode sited at C7-T1. A = control; B = during sublaminal wiring; c = during distraction; D = 10 min after distraction. Baseline latency: L = 15.48 ms, R = 15.72 ms; baseline amplitude: L = 0.6 uV and R = 0.2 uV.
mean blood loss [16]. Enflurane and opioid supplementation are of additional benefit by reducing operating time, blood loss and the need for blood replacement [17]. It has been suggested that it is possible to eliminate completely the requirement for transfusion in routine posterior spinal surgery, if meticulous surgical and anaesthetic techniques are combined with autotransfusion [18]. No complication of induced hypotension has been recorded in this institution and a reduction in mean arterial pressure to 62 mm Hg during anaesthesia for AIS resulted in only a 25% change in mean overall amplitude of SEP [5, 19]. A possible additive effect of hypotension on the SEP during spinal distraction should be considered, as this has been shown to occur in the feline spinal cord compression model [20] j however, there is no study which has quantified or compared this with the individual effects of induced hypotension and spinal distraction on the
Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
Scoliosis is often a part of various malformation syndromes, and with the added factor of accelerated skeletal growth, an incidence of 4 % is not unexpected in the Sotos' syndrome [2]. Metacarpophalangeal analysis aids diagnosis [6] and although the syndrome is inherited as an autosomal dominant disorder, a recessive pattern of inheritance has also been suggested [7]. Excessive head growth in early infancy is a typical feature [8], and hydrocephalus with increased intracranial pressure has been reported [9]. Craniofacial features at variance with the characteristic description include acrocephaly and maxillary prominence. Steepness of the anterior cranial base and protrusion of the middle and lower face shown by cephalometric radiographs [10], with potential for difficulty with the airway, also have been reported. Increased somatomedin activity and increased secretion of growth hormone have been observed [9], and it is essential to exclude glucose intolerance. Other features of possible relevance to anaesthesia include lipid storage myopathy [11], hypotonia and clumsiness [12], high arched palate complex [13] and cardiac abnormalities [14]. High rates of emotional and behavioural disorders are common, and all children in one study presented with cognitive impairment or mental retardation [15], which may be associated with hyperactive and aggressive behaviour [7]. This presents problems of peroperative co-operation, especially with regard to the wake-up test. Continuous SEP monitoring is therefore prudent if not mandatory in these patients, as disappearance of one of the triple peaks characteristic of the extradural SEP trace or a decrease in overall amplitude by 50% would indicate immediately a need for modification of the surgical manoeuvre. Neither of these events was noted during the initial or subsequent surgical procedure in this patient (fig. 1). Apart from minor variations, the anaesthetic management of this patient conformed to that used at the Royal National Orthopaedic Hospital, for posterior spinal fusions in adolescent idiopathic scoliosis (AIS) [5]. Induced hypotension is used routinely in scoliosis surgery and is associated with significantly less peroperative
SPINAL FUSION IN SOTOS' SYNDROME
731
Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
4. Anderson SK, Loughnan BA, Hetreed MA. A technique for monitoring evoked potentials during scoliosis and brachial plexus surgery. Annals of the Royal College of Surgeons of England 1990; 72: 321-323. 5. Youngman PM, Edgar MA. Posterior spinal fusion and instrumentation in the treatment of adolescent idiopathic scoliosis. Annals of the Royal College of Surgeons of England 1985; 67: 313-317. 6. Butler MG, Dijkstra PF, Meaney FJ, Gale DD. Metacarpophalangeal pattern profile analysis in Sotos syndrome: a follow-up report on 34 subjects. American Journal of Medical Genetics 1988; 29: 143-147. 7. Boman H, Nilsson D. Sotos syndrome in two brothers. Clinical Genetics 1980; 18: 421-427. 8. McNicholl B. Excessive head growth in early infancy: a feature of Soto's syndrome. Irish Medical Journal 1987; 80: 261-262. 9. Ranke MB, Bierich JR. Cerebral gigantism of hypothalamic origin. European Journal of Pediatrics 1983; 140: 109-111. 10. Bale AE, Drum MA, Parry DM, Mulvihill JJ. Familial Sotos syndrome (cerebral gigantism): craniofacial and psychological characteristics. American Journal of Medical Genetics 1985; 20: 613-624. 11. Diliberti JH, Weleber RG, Budden S. RuvalcabaMyhre—Smith syndrome: a case with probably autosomaldominant inheritance and additional manifestations. American Journal of Medical Genetics 1983; IS: 491^195. 12. Ferrier PE, de-Meuron G, Korol S, Hauser H. Cerebral gigantism (Sotos syndrome) with juvenile macular degeneration. Helvetica Paediatrica Ada 1980; 35: 97-102. 13. Villaverde MM, Da-Silva JA. Sotos' syndrome: hypertelorism, antimongoloid slant of eye, and high arched palate complex. Journal of the Medical Society of New Jersey 1971; 68: 805-808. 14. Di-Marco G, Levantesi G, Parisi G, Chiarelli A. Congenital cardiopathy in a patient with Sotos syndrome. Description of a case. Giornale Itahano Cardtologia 1989; 19: 453-^155. 15. Varley CK, Crnic K. Emotional, behavioral, and cognitive status of children with cerebral gigantism. Journal of Development and Behavioral Pediatrics 1984; 5: 132-134. 16. Malcolm Smith NA, McMaster MJ. The use of induced hypotension to control bleeding during posterior fusion for scoliosis. Journal of Bone and Joint Surgery. British Volume 1983; 65: 255-258. 17. Patel NJ, Patel BS, Paskin S, Laufer S. Induced moderate hypotensive anesthesia for spinal fusion and Harringtonrod instrumentation. Journal of Bone and Joint Surgery. American Volume 1985; 67: 1384-1387. 18. Phillips WA, Hensinger RN. Control of blood loss during scoliosis surgery. Clinical Orthopaedics and Related Research 1988; 229: 88-93. REFERENCES 19. Loughnan BA, King MJ, Grundy EM, Young DL, Hall 1. Winship IM. Sotos syndrome—autosomal dominant inGM. Effects of halothane oh somatosensory evoked heritance substantiated. Clinical Genetics 1985; 28: potentials recorded in the extradural space. British Journal 243-246. of Anaesthesia 1989; 62: 297-300. 2. De-Giorgi G, Carnevale F, Za GC, Greco MG. La 20. Brodkey JS, Richards DE, Blasingame JP, Nulsen FE. scoliosi nella sindrome di Sotos. (Scliosis in Soto's Reversible spinal cord trauma in cats. Additive effects of syndrome.) Chirurgia degli Organi di Movimento 1982; 68: direct pressure and ischaemia. Journal of Neurosurgery 815-818. 1972; 37: 591-593. 3. Ruvalcaba RH, Myhre S, Smith DW. Sotos syndrome 21. Pathak KS, Ammadio M, Kalamchi A, Scoles PV, Shaffer with intestinal polyposis and pigmentary changes of the JW, MacKay JW. Effects of halothane enflurane and isoflurane on somatosensory evoked potentials during genitalia. Clinical Genetic* lSf-O; 18: 413-416.
SEP during scoliosis surgery. This information would be of value in balancing the risks and consequences of excessive blood loss and transfusion against the degree of correction achievable without risk to the spinal cord. In a study of the effects of halothane, enflurane and isoflurane on SEP during nitrous oxide based anaesthesia, it was found that enflurane and isoflurane resulted in less alteration of somatosensory cortical evoked potential than halothane [21]. This finding may have been a consequence of a pronounced effect of inhalation agents on SEP recorded cortically [22], as it has been demonstrated that extradural SEP are affected minimally by halothane in an end-tidal concentration of 1.5% [19]. SEP recordings for the two operations in this patient confirm an additional advantage of the extradural technique— that of reproducibility. The incidence of hook failures following posterior spinal fusion in AIS is 2.5% in this centre and may be related to deep wound infection. The top hook is found to dislodge more frequently (63%) than the bottom hook (37%). In a review of 319 patients over a period of 8 yr, not one case of double hook failure was noted, suggesting that such a complication may be peculiar to this syndrome [5]. Trauma to bone and muscle, blood loss and hypotensive anaesthesia might be reasonably expected to compromise renal function, but a prospective study of 43 patients undergoing a total of 52 operations for scoliosis correction failed to reveal any evidence of renal impairment [23]. The haematuria following the second operation in our patient was therefore worrying, but ceased spontaneously and remained unexplained despite exhaustive investigation and consideration of rarer causes such as adverse reaction to cephalosporins, known to interfere with clotting.
732 nitrous oxide based anesthesia. Anesthesiology 1987; 66: 753-757. 22. McPherson RW, Mahla M, Johnson R, Traystman RJ. Effects of enflurane, isoflurane and nitrous oxide on somatosensory evoked potentials during fentanyl anesthesia. Anesthesiology 1985; 62: 626-633.
BRITISH JOURNAL OF ANAESTHESIA 23. Rylance PB, Carli F, McArthur SE, Ransford AO, Mansell MA. The effect of induced hypotension and tissue trauma on renal function in scoliosis surgery. Journal of Bone and Joint Surgery. British Volume 1988; 70: 127-129.
Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
POSTERIOR SPINAL FUSION IN SOTOS' SYNDROME D. SURESH Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
There was no family history of Sotos' syndrome. Manifest features included growth patSotos' syndrome (synonym: cerebral gigantism) tern, hypertelorism and palpebral fissures, progis the association of mental retardation, macro - nathism, receding hairline and large spadelike cephaly and prenatal onset of accelerated hands with a single palmar crease on the right. growth. The rapid skeletal growth may account Pubertal development was nearly complete, with for a 4% incidence of scoliosis. General an- small external genitalia and scanty pubic hair, but aesthesia using halothane or enflurane in nitrous no pigmentation [3]. He had a clumsy gait, and oxide and oxygen, with opioid supplementation showed psychomotor retardation. He could be and labetalol to induce moderate hypotension, difficult and stubborn and only his parents were appeared to be a satisfactory technique for able to influence his behaviour, although intelcorrective spinal surgery. The potential problems lectually he was not as impaired as he appeared. The main musculo-skeletal features were are discussed, with mental retardation and sometimes aggressive behaviour contraindicating a accelerated linear growth and skeletal maturation. "wake-up" test. Extradural somatosensory Kyphoscoliosis was obvious from the age of 4 yr, evoked potential monitoring is a satisfactory with some pelvic instability. When he was 11 yr, alternative. Hook failures seem more likely than a right thoracic scoliosis was treated with a brace in patients undergoing surgery for adolescent for 8 months. An x-ray examination in and out of the brace showed a 48° right thoracic curve at the idiopathic scoliosis. T4-10 level, and a 52° left lumbar curve between T i l and L4. When he was admitted for correction KEY WORDS of his scoliosis, this had deteriorated to a 70° right Anaesthesia: general. Complications: Sotos' syndrome. and a 70° left lumbar scoliosis, represting a 20° Surgery: spinal fusion. deterioration over the previous 10 months. At the age of 14 yr, the subject weighed 90 kg, Sotos' syndrome (synonym: cerebral gigantism) his height was 170 cm and his arm span measured is the association of mental retardation, macro- 178 cm. Cardiovascular and neurological assesscephaly and prenatal onset of accelerated growth ment were unremarkable. Lung function tests inherited as an autosomal dominant trait [1]. Bone revealed a restrictive defect with a forced vital age is advanced in all children, and although capacity (FVC) of 1.7 litre (32% of predicted scoliosis is not part of the syndrome complex, norm). A glucose tolerance test and anterior rapid skeletal growth may account for a 4% pituitary functions were normal and a lateral incidence as reported in one series [2]. Patients radiograph of the skull showed a normal pituitary may therefore present for surgical correction of fossa. Routine haematology and biochemistry their scoliosis. screens were within normal limits, as were serum concentrations of 17-OH progesterone, calcium, CASE REPORT phosphate and alkaline phosphatase. He snored A male child was delivered by forceps at 42 weeks following an uncomplicated pregnancy; he weighed 4.2 kg at birth. He suffered from "jerks" D. SURESH, F.F.A.R.C.S.I., Anaesthetics Unit, The Royal London Hospital, Whitechapel, London El IBB. Present which ceased at age 1 yr, and his early motor, address: Department of Anesthesiology, Duke University speech and language development was reported Medical Center, Durham, NC 27710, U.S.A. Accepted for also to be delayed. Publication: January 7, 1991. SUMMARY
SPINAL FUSION IN SOTOS' SYNDROME
729
and had been investigated recently for sleep apnoea, the results of which were reported as negative. There were recent behavioural problems and his behavioural age was estimated to be about 6 yr.
months, lasted 6 h 15 min. The patient was awake a few minutes after antagonism of neuromuscular block, when clinical testing allowed confirmation of intact neurological function as indicated by the continuous intraoperative somatosensory evoked potential (SEP) monitoring.
Anaesthesia
Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
Because the patient hated needles, premedication consisted of diazepam 10 mg orally. Both Postoperative course parents were present during induction of anThere was a slight ooze from the wound and aesthesia, which would have been impossible perioperative blood loss totalled 3250 ml. There without their calming influence. The facemask was a short episode of unexplained suprawas held by the father for induction of sleep with ventricular tachycardia which settled later to halothane in oxygen. Vecuronium 10 mg was about 120 beat min"1. An infusion of papaveretum given to facilitate intubation with a 9.0-mm cuffed 4 mg h"1 provided satisfactory analgesia. He reorotracheal tube, with additional intermittent ceived assisted positive pressure ventilation with a doses to facilitate IPPV. Anaesthesia was main- Bird ventilator according to a standard procedure tained with 1-2% halothane and 65% nitrous —initially hourly until his FVC was 25 % of best oxide in oxygen. A radial artery cannula and a preoperative value, then 2 hourly until FVC was right internal jugular cannula were inserted. The 50%, and thereafter 4 hourly until 75% of the patient was placed prone on a Montreal mattress baseline values had been attained [5]. and the extradural space at C7-T1 was located The boy made satisfactory progress until 2 using the "hanging drop" technique with a 16- weeks later, when an erect radiograph of the spine gauge Tuohy needle [4]. A 3-French gauge bipolar revealed that the top hook at T4 had cut out and recording electrode was positioned in the extra- approximately 20° correction had been lost. He dural space and connected to a Medelec MS 91 was prepared for surgery on the following day. electomyograph recorder. The right and left This time there was less objection to both i.m. posterior tibial nerves were stimulated alternately premedication and i.v. induction with thiopenvia skin surface electrodes using a square wave tone. The trachea was intubated using suxaimpulse of 0.2 ms duration at an intensity of methonium and IPPV was facilitated by a single 150 uV. The stimulation frequency was 20 s"1 and bolus of vecuronium 5 mg. Anaesthesia was 1000 responses were averaged with a resolution of maintained with enflurane and nitrous oxide in 0.33 ms and with the filters set at 200 Hz to oxygen and intermittent doses of papaveretum 2 KHz. provided analgesia. Labetalol (total 40 mg) was used again for hypotension to systolic values Intermittent doses of pethidine were given to supplement anaesthesia, and hypotension to sys- similar to those in the first operation. SEP tolic pressures of about 70 mm Hg was achieved monitoring was uncomplicated and re-fixation of with labetalol (total 85 mg). As the quality of the upper rod was completed uneventfully and traces from the spinal cord monitoring was poor, with minimal blood loss. A urinary catheter was a distal electrode was inserted at Ll-2 and this not inserted on this 1occasion. As before, tachyprovided good traces between this and the cardia (140 beat min" ) and a transient pyrexia of stimulating electrode, but not superiorly. An 39 °C were noted on the first day after operation. additional electrode was sited therefore at the Six days later, several episodes of frank painless T3—4 interspace; this resulted eventually in haematuria occurred, the cause for which resatisfactory recordings from the posterior tibial mained unexplained despite exhaustive investignerves. The operative procedure consisted of ations. This settled as spontaneously as it began internal fixation of a contoured Harrington rod, and allowed discharge from hospital the following stabilized at each level with Luque sublaminal week. wiring. Intraoperative fluid replacement included When reviewed 1 month later, radiography crystalloid 1000 ml, colloid 2000 ml and 3 units of revealed that the lower hook at Tl2 had dislodged. plasma reduced blood. Fortunately, the multilevel sublaminal wire fixThe procedure, including customizing a sub- ation reinforced by the plaster cast maintained a ortholene plaster cast prescribed for the next 8 reasonable correction for the thoracic curve and
BRITISH JOURNAL OF ANAESTHESIA
730
the patient was advised to remain in plaster for 8 months.
A 13:20 L 15.72 ms
Control
R 15.96 ms
B 13:35 L 15.60 ms
Wiring
R 15.72 ms
C 14:25
L 15.84 ms
Distraction
R 15.84 ms
D 14:35
L 15.84 ms
After distraction
R 15.96 ms
DISCUSSION
0.4
3 ms
FIG. 1. Sample extradural SEP recordings in response to alternate right and left posterior tibial nerve stimulation from electrode sited at C7-T1. A = control; B = during sublaminal wiring; c = during distraction; D = 10 min after distraction. Baseline latency: L = 15.48 ms, R = 15.72 ms; baseline amplitude: L = 0.6 uV and R = 0.2 uV.
mean blood loss [16]. Enflurane and opioid supplementation are of additional benefit by reducing operating time, blood loss and the need for blood replacement [17]. It has been suggested that it is possible to eliminate completely the requirement for transfusion in routine posterior spinal surgery, if meticulous surgical and anaesthetic techniques are combined with autotransfusion [18]. No complication of induced hypotension has been recorded in this institution and a reduction in mean arterial pressure to 62 mm Hg during anaesthesia for AIS resulted in only a 25% change in mean overall amplitude of SEP [5, 19]. A possible additive effect of hypotension on the SEP during spinal distraction should be considered, as this has been shown to occur in the feline spinal cord compression model [20] j however, there is no study which has quantified or compared this with the individual effects of induced hypotension and spinal distraction on the
Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
Scoliosis is often a part of various malformation syndromes, and with the added factor of accelerated skeletal growth, an incidence of 4 % is not unexpected in the Sotos' syndrome [2]. Metacarpophalangeal analysis aids diagnosis [6] and although the syndrome is inherited as an autosomal dominant disorder, a recessive pattern of inheritance has also been suggested [7]. Excessive head growth in early infancy is a typical feature [8], and hydrocephalus with increased intracranial pressure has been reported [9]. Craniofacial features at variance with the characteristic description include acrocephaly and maxillary prominence. Steepness of the anterior cranial base and protrusion of the middle and lower face shown by cephalometric radiographs [10], with potential for difficulty with the airway, also have been reported. Increased somatomedin activity and increased secretion of growth hormone have been observed [9], and it is essential to exclude glucose intolerance. Other features of possible relevance to anaesthesia include lipid storage myopathy [11], hypotonia and clumsiness [12], high arched palate complex [13] and cardiac abnormalities [14]. High rates of emotional and behavioural disorders are common, and all children in one study presented with cognitive impairment or mental retardation [15], which may be associated with hyperactive and aggressive behaviour [7]. This presents problems of peroperative co-operation, especially with regard to the wake-up test. Continuous SEP monitoring is therefore prudent if not mandatory in these patients, as disappearance of one of the triple peaks characteristic of the extradural SEP trace or a decrease in overall amplitude by 50% would indicate immediately a need for modification of the surgical manoeuvre. Neither of these events was noted during the initial or subsequent surgical procedure in this patient (fig. 1). Apart from minor variations, the anaesthetic management of this patient conformed to that used at the Royal National Orthopaedic Hospital, for posterior spinal fusions in adolescent idiopathic scoliosis (AIS) [5]. Induced hypotension is used routinely in scoliosis surgery and is associated with significantly less peroperative
SPINAL FUSION IN SOTOS' SYNDROME
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Downloaded from http://bja.oxfordjournals.org/ at University of Tennessee ? Knoxville Libraries on August 13, 2015
4. Anderson SK, Loughnan BA, Hetreed MA. A technique for monitoring evoked potentials during scoliosis and brachial plexus surgery. Annals of the Royal College of Surgeons of England 1990; 72: 321-323. 5. Youngman PM, Edgar MA. Posterior spinal fusion and instrumentation in the treatment of adolescent idiopathic scoliosis. Annals of the Royal College of Surgeons of England 1985; 67: 313-317. 6. Butler MG, Dijkstra PF, Meaney FJ, Gale DD. Metacarpophalangeal pattern profile analysis in Sotos syndrome: a follow-up report on 34 subjects. American Journal of Medical Genetics 1988; 29: 143-147. 7. Boman H, Nilsson D. Sotos syndrome in two brothers. Clinical Genetics 1980; 18: 421-427. 8. McNicholl B. Excessive head growth in early infancy: a feature of Soto's syndrome. Irish Medical Journal 1987; 80: 261-262. 9. Ranke MB, Bierich JR. Cerebral gigantism of hypothalamic origin. European Journal of Pediatrics 1983; 140: 109-111. 10. Bale AE, Drum MA, Parry DM, Mulvihill JJ. Familial Sotos syndrome (cerebral gigantism): craniofacial and psychological characteristics. American Journal of Medical Genetics 1985; 20: 613-624. 11. Diliberti JH, Weleber RG, Budden S. RuvalcabaMyhre—Smith syndrome: a case with probably autosomaldominant inheritance and additional manifestations. American Journal of Medical Genetics 1983; IS: 491^195. 12. Ferrier PE, de-Meuron G, Korol S, Hauser H. Cerebral gigantism (Sotos syndrome) with juvenile macular degeneration. Helvetica Paediatrica Ada 1980; 35: 97-102. 13. Villaverde MM, Da-Silva JA. Sotos' syndrome: hypertelorism, antimongoloid slant of eye, and high arched palate complex. Journal of the Medical Society of New Jersey 1971; 68: 805-808. 14. Di-Marco G, Levantesi G, Parisi G, Chiarelli A. Congenital cardiopathy in a patient with Sotos syndrome. Description of a case. Giornale Itahano Cardtologia 1989; 19: 453-^155. 15. Varley CK, Crnic K. Emotional, behavioral, and cognitive status of children with cerebral gigantism. Journal of Development and Behavioral Pediatrics 1984; 5: 132-134. 16. Malcolm Smith NA, McMaster MJ. The use of induced hypotension to control bleeding during posterior fusion for scoliosis. Journal of Bone and Joint Surgery. British Volume 1983; 65: 255-258. 17. Patel NJ, Patel BS, Paskin S, Laufer S. Induced moderate hypotensive anesthesia for spinal fusion and Harringtonrod instrumentation. Journal of Bone and Joint Surgery. American Volume 1985; 67: 1384-1387. 18. Phillips WA, Hensinger RN. Control of blood loss during scoliosis surgery. Clinical Orthopaedics and Related Research 1988; 229: 88-93. REFERENCES 19. Loughnan BA, King MJ, Grundy EM, Young DL, Hall 1. Winship IM. Sotos syndrome—autosomal dominant inGM. Effects of halothane oh somatosensory evoked heritance substantiated. Clinical Genetics 1985; 28: potentials recorded in the extradural space. British Journal 243-246. of Anaesthesia 1989; 62: 297-300. 2. De-Giorgi G, Carnevale F, Za GC, Greco MG. La 20. Brodkey JS, Richards DE, Blasingame JP, Nulsen FE. scoliosi nella sindrome di Sotos. (Scliosis in Soto's Reversible spinal cord trauma in cats. Additive effects of syndrome.) Chirurgia degli Organi di Movimento 1982; 68: direct pressure and ischaemia. Journal of Neurosurgery 815-818. 1972; 37: 591-593. 3. Ruvalcaba RH, Myhre S, Smith DW. Sotos syndrome 21. Pathak KS, Ammadio M, Kalamchi A, Scoles PV, Shaffer with intestinal polyposis and pigmentary changes of the JW, MacKay JW. Effects of halothane enflurane and isoflurane on somatosensory evoked potentials during genitalia. Clinical Genetic* lSf-O; 18: 413-416.
SEP during scoliosis surgery. This information would be of value in balancing the risks and consequences of excessive blood loss and transfusion against the degree of correction achievable without risk to the spinal cord. In a study of the effects of halothane, enflurane and isoflurane on SEP during nitrous oxide based anaesthesia, it was found that enflurane and isoflurane resulted in less alteration of somatosensory cortical evoked potential than halothane [21]. This finding may have been a consequence of a pronounced effect of inhalation agents on SEP recorded cortically [22], as it has been demonstrated that extradural SEP are affected minimally by halothane in an end-tidal concentration of 1.5% [19]. SEP recordings for the two operations in this patient confirm an additional advantage of the extradural technique— that of reproducibility. The incidence of hook failures following posterior spinal fusion in AIS is 2.5% in this centre and may be related to deep wound infection. The top hook is found to dislodge more frequently (63%) than the bottom hook (37%). In a review of 319 patients over a period of 8 yr, not one case of double hook failure was noted, suggesting that such a complication may be peculiar to this syndrome [5]. Trauma to bone and muscle, blood loss and hypotensive anaesthesia might be reasonably expected to compromise renal function, but a prospective study of 43 patients undergoing a total of 52 operations for scoliosis correction failed to reveal any evidence of renal impairment [23]. The haematuria following the second operation in our patient was therefore worrying, but ceased spontaneously and remained unexplained despite exhaustive investigation and consideration of rarer causes such as adverse reaction to cephalosporins, known to interfere with clotting.
732 nitrous oxide based anesthesia. Anesthesiology 1987; 66: 753-757. 22. McPherson RW, Mahla M, Johnson R, Traystman RJ. Effects of enflurane, isoflurane and nitrous oxide on somatosensory evoked potentials during fentanyl anesthesia. Anesthesiology 1985; 62: 626-633.
BRITISH JOURNAL OF ANAESTHESIA 23. Rylance PB, Carli F, McArthur SE, Ransford AO, Mansell MA. The effect of induced hypotension and tissue trauma on renal function in scoliosis surgery. Journal of Bone and Joint Surgery. British Volume 1988; 70: 127-129.
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