Child's Nerv Syst (1996) 12:248-253 �9 Springer-Verlag 1996

Char le s Teo S a l i m R a h m a n F r e d e r i c k A. B o o p B r u c e C h e r n y

Complications of endoscopic neurosurgery

Received: 2 October 1995

C. Teo ([]) - S. Rahman. F.A. Boop B. Cherny Division of Pediatric Neurosurgery, Arkansas Children's Hospital, 800 Marshall Street, Little Rock, AR 72202, USA Tel.: (501) 320-1448 Fax: (501) 320-3621

A b s t r a c t Neuroendoscopy is ra- pidly becoming an essential part of the neurosurgeon 's repertoire. Cur- rently, very few studies have identi- fied the complicat ions of this new technique, yet many have warned of the steep learning curve associated with its practice. We have reviewed the last 173 neuroendoscopic proce- dures performed by one surgeon and identified two distinct groups of complicat ions: those that have clini- cally significant sequelae and those that cause concern intraoperatively but no overt clinical problems. The 173 procedures were performed on 152 patients. Of these patients, 11 suffered significant complicat ions (7%). Twenty- two of the procedures

were complicated by intraoperative problems (13%). The incidence of insignificant complicat ions appeared to decrease with experience, whereas that of the significant ones did not. These complicat ions occurred in as- sociation with a wide variety of ope- rations over a 2-year period. We con- clude that neuroendoscopy is a rela- tively safe technique with an overall 7% complicat ion rate and a steep learning curve, and that, with a few simple guidelines, it can be em- ployed by all neurosurgeons for the betterment of their patients.

K e y w o r d s Compl icat ion �9 E n d o s c o p y . Hydrocephalus �9 Neuroendoscopy �9 Pediatric

Introduction

T h e indications for the use of endoscopy in neurosurgery continue to expand [ 1 - 3 , 7, 8, 11, 12, 14, 16]. Originally confined to the ventricular cavities, with improvements in technology and instrumentation endoscopy has now moved into the subarachnoid and intra-axial spaces. Al though complicat ions appear to be rare [ 6 - 9 ] , very few publica- tions have addressed this issue specifically [4, 15]. Fur- thermore, the present authors have felt that endoscopy of the cranial cavity is difficult and potentially hazardous - sentiments not reflected in the literature [7, 9, 16]. There- fore, we analyzed the outcome of all patients who under- went endoscopic procedures by the one surgeon(C. T.) over the last 3 years, highlighting clinically significant as well as clinically insignificant complications.

Patients and methods

The first author (C. T.) has utilized endoscopy in 152 patients to per- form 173 procedures at the Arkansas Children's Hospital, The Uni- versity of Arkansas for Medical Sciences, Baptist Hospital, and at the John McClellan Veteran's Hospital in Little Rock, Arkansas. Op- erative notes, imaging, and intraoperative videos, when available, were reviewed. Patients ranged in age from 1 day to 72 years; most were children or infants. In the majority of cases, surgery was per- formed on the same day as admission and required less than 24 h re- covery. A wide variety of procedures was performed (Table 1) using several different endoscopes (Fig. 1). Most intraventricular endos- copy was performed using a rigid lens scope with working and irri- gating channels. These scopes ranged in diameter from 3 mm to 7 mm with variable tip angles (0~176 The flexible, fiberoptic scopes were utilized in spinal cases and some endoscopy-assisted cranioto- mies. Carpal tunnel decompression was performed using the single portal technique (Agee, 3M). Irrigation was achieved using Ringer's lactated solution in a 20-ml syringe connected to the scope through

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Fig. 1 Selection of endoscopes and instruments used for both ventricular and subarachnoid procedures

Table 1 Endoscopic procedures (n= 173) performed in 152 neuro- surgical patients

Procedure n

III ventriculostomy Endoscopy-assisted open surgery Cyst fenestration Carpal tunnel decompression Septum pellucidotomy Shunt placement Intraventricular tumors Ventriculoscopy Spinal Removal of intraventricular hemorrhage Aqueductal plasty Choroid plexectomy

Results

The length of patients ' postoperative stay varied from 1 55 day to 3 months, depending upon the occurrence of com- 29 plications and the existence of associated illnesses. 19 Group 1 patients had an average stay of 1.7 days, and group 13 2, 22 days. Of the 173 procedures performed, clinically 12 significant complicat ions occurred after 13 (7.5%) and 11 8 clinically insignificant complicat ions after 22 (13%). All 7 clinically significant complicat ions occurred in group 1 6 patients and prolonged hospital stay by an average of 6 4.9 days. Clinically insignificant complicat ions prolonged 5 2 the hospital stay by 0.4 days. This reflected the surgeon's

caution, not the patient 's condition. These insignificant complicat ions are listed in Table 2. Brief case histories are given below for the significant complicat ions (Table 3).

clear plastic extension tubing. B arbotage and intermittent disconnec- tion of the syringe to allow egress of fluid gave good irrigation with- out major changes in intracranial pressure. A self-retaining retractor system was used whenever procedures required instrumentation. Co- agulation was achieved utilizing a Bugbee-type, insulated, monopo- lar electrode.

Patients were divided into two groups depending on their con- comitant diseases. Group 1 (n= 130) patients were those admitted for a primary neurosurgical condition who required an endoscopic pro- cedure only. Group 2 (n = 22) patients had other disease processes re- quiring extended hospitalization - premature infants, children with brain tumors requiring chemotherapy, etc. Patients were followed for an average of 11 months, ranging from 1 to 24 months. Patients with complications had an average follow-up period of 13 months.

Complications were considered insignificant if there were no overt negative, clinical sequelae. If an intraoperative hemorrhage re- quired transfusion, it became significant. If hemorrhage was con- trolled without resultant neurological deficit or the need for transfu- sion, it was considered insignificant.

Case 1

A 21-year-old man with neurofibromatosis type 2, tectal glioma, and shunt~dependent hydrocephalus presented with a shunt malfunction and underwent a III ventriculos- tomy. He was discharged the next day with complete resolution of his symptoms. Two weeks later he was brought into the emergency department by his mother, in a near-comatose state. He was extremely weak, confused, and semiconscious. A C T scan demonstrated good resolu- tion of his ventr iculomegaly (Fig. 2). He had not taken fluids for several days and his urine was extremely con- centrated. Serum sodium concentrat ion on readmission was 197 mmol/1. MRI confirmed the clinical suspicion of

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Table2 Clinically insignifi- cant complications of endosco- pic neurosurgery (EAOS endos- copy-assisted open surgery)

Procedure Complication No. of cases

Cyst fenestration Cyst fenestration Ventriculostomy III ventricular tumors III ventriculostomy III ventricutostomy EAOS/ventriculoscopy

Contusion to head of caudate 1 Disorientation 2 Hemorrhage 6 Damage to fornix 6 Scope-to-foraminal disproportion 4 Increase in insulin-like growth factor 1 1 Brain contusion 2

Table 3 Clinical!y significant complications of endoscopic neurosurgery (IVH intraventricular hemorrhage, EOM extraocular eye move- ments~

Diagnosis Procedure Complication Outcome

Neurofibromatosis Spina bifida Spina bifida Spina bifida Aqueduct stenosis Dandy-Walker cyst Isolated ventricle Posterior fossa arachnoid cyst Aqubdact stenosis Aqueduct stenosis Pituitary adenoma

III ventriculostomy III ventriculostomy III ventriculostomy III ventriculostomy III ventriculostomy Ventriculoscopy Septum pellucidotomy Cyst fenestration Aqueductal plasty Aqueductat ptasty EAOS

Loss of thirst Incomplete resolution Increase in appetite Complete resolution Diabetes insipidus Complete resolution CSF leak Failed ventriculostomy Amenorrhea No improvement Cardiac arrest Good : IVH, seizure, hemiparesis Fair CSF leak, infection Good Dysconjugate EOM Complete resolution Dysconjugate EOM Complete resolution CSF leak Good

hypothalamic damage to his dorsomedial nucleus (thirst center: Fig. 3)

Case 2

An 8-year-old girl with spina bifida and shunt-dependent hydrocePhalus had six revisions in 1 year. She presented with another malfunction, underwent an endoscopic III ventriculostomy, and was discharged the following day in good neurological condition. Two weeks later she pre- sented tO the outpatient clinic complaining of excessive ap- petite and was found to have gained 12 lb (5.4 kg) in weight. Follow-up CT revealed a decrease in ventricutar size but no hypothalamic contusion. When seen 3 months later, the girl 's appetite had returned to normal, her weight gain had been lost, and she was shunt-independent.

Case 3

A 1-week-old boy with spina bifida and worsening ventricutomegaly underwent an endoscopic III ventricu- lostomy. He developed transient diabetes insipidus con- firmed by laboratory studies between days 2 and 7 postop- eratively. Serum sodium concentrations were never above 147 mmol/1 and no treatment was required. The III ven- triculostomy failed within 2 weeks of surgery and a shunt was placed at 3 weeks of age. At the time of shunt place-

Fig. 2a,b Pre- and postventricul0s~omy CT in Case 1. The post- operative scan (b) shows resolution Of tl~e:hydr6cephalus with smal- ler ventricles and bigger subarachnoid space. There is a hematoma in and around the hypothalamus

merit, the III ventricle was examined and the hole found to be patent.

Case 4

A 1-week-old boy with spina bifida had a III ventriculos- tomy for progressive hydrocephalus. Five days after sur-

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bradycardia (heart rate dropped from 80 to 36). This re- solved immediately on retraction of the scope. A second attempt resulted in asystole for approximately 10 s. She re- verted to sinus rhythm spontaneously without hemody- namic compromise. The III ventricular floor was almost completely perforated and a third attempt with minimal ex- ertion completed the fenestration. The patient was placed under intensive care overnight and was discharged the next day. She remains shunt-independent 12 months later.

Fig. 3 Postoperative MRI of the patient in case 1, showing evidence of hemorrhage in the lateral wall and roof of the Ill ventricle

gery the frontal scalp incision began leaking clear cerebro- spinal fluid (CSF). Ultrasound examination confirmed per- sistent hydrocephalus and the child underwent placement of a ventriculoperitoneal shunt at day 15 of life. The CSF never became infected.

Case 5

An 11-year-old girl with congenital aqueductal stenosis presented with headaches after minor head trauma. CT scan demonstrated triventricular hydrocephalus and she under- went an endoscopic' III ventriculostomy. She was dis- charged the following day with complete resolutio n of her symptoms. Subsequent follow-up studies have shown only a mild decrease in ventricular size but an asymptomatic girl with stable psyChometric evaluations. At her last clini c visit, 2 years after Ventriculostomy, her mother stated that she had ceased menstruating following the surgery. She had only just commenced menses at the time of surgery.

Case 6

A 14-year-old girl with shunt-dependent hydrocephalus and Dandy-Walker syndrome presented with a shunt mal- function and underwent endoscopic III ventriculostomy. Once the scope was introduced into the III ventricle, through the foramen of Monro, the floor was visualized and noted to be more opaque than usual. The first attempt to puncture the floor with the scope resulted in intense

Case 7

A 3-month-old boy was born with a large intraventricular cyst. At birth, he had no signs or symptoms of intracranial hypertension and was therefore discharged home. When he returned to the clinic, he was irritable and feeding poorly with a full fontanel and split sutures. CT Showed progres- sion of the cyst and more mass effect. He underwent en- doscopic fenestration of the cyst into the lateral ventricle. There was a small amount of bleeding during the proce- dure that stopped readily with monopolar coagulation. The CSF was clear at the end of the operation: A catheter con- nected to a burr hole CSF reservoir was left in the ventri- cle. The child recovered well and was to be sent home 48 h after surgery with a soft fontanel. Nursing staff witnessed seizures just before discharge and his fontanel was noted to be full. CT showed a large intraventricular hemorrhage with a possible intra-axial component (Fig. 4). The boy's seizures progressed to status epilepticus and he had a per- sistent mild left hemiparesis. The reservoir was tapped on two occasions, but he was discharged 3 weeks later in good neurological condition without a shunt.

Case 8

A 2-year-old girl presented with headache and mild devel- opmental delay. MRI showed a very large posterior fossa arachnoid cyst with marked midline shift and mass effect. Although it appeared to be causing no specific brainstem or cranial nerve palsies, its size was alarming enough for surgery to be recommended. The cyst was drained endo- scopically into; the basal cisterns and IV ventricle. The girl was discharged home on day 2 and returned on day 5 with CSF leaking from the wound. Postoperative MRI showed a diminution in cyst size without hydrocephalus. Initial management consisted of percutaneous drainage and a pressure dressing. Forty-eight hours after this was re- moved, the CSF leak recommenced. The patient was taken to the operating room for repair of the leak using a dural patch graft. CSF taken at the tim e of surgery demonstrated infection with Staphylococcus epidermidis. This was treated with antibiotics for 10 days and the patient was then discharged home, without a leak, asymptomatic, with a smaller Cyst and shunt-independent.

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sphenoidal removal of the tumor simultaneously. Postope- rative imaging showed excellent macroscopic tumor re- moval. Despite free fat grafting within the sphenoid sinus, she developed CSF rhinorrhea for 7 days, eventually re- quiring endoscopic packing of the sinus with more fat and fibrin glue.

Discussion

Fig. 4 a Pre- and b postoperative CT scans in case 7. The right ven- tricular cyst was fenestrated endoscopically into the right and left ventricles through a septum pellucidotomy. The CSF was clear at the end of the procedure. The postoperative CT scan shows intraventri- cular and intra-axial hemorrhage

Case 9

A 2-month-old girl with progressive hydrocephalus from a grade IV intraventricular hemorrhage was shunted with- out complication. Although the fontanel remained soft, persistent episodes of apnea and bradycardia prompted a repeat CT scan which showed an isolated and enlarging IV ventricle. A stent (3 mm in diameter) was placed endos- copically through the aqueduct of Sylvius. The patient awoke with obvious dysconjugate eye movements. These resolved spontaneously within 1 week and the stent has re- mained patent.

Case 10

A 3-month-old premature infant with shunt-dependent hy- drocephalus secondary to a grade IV intraventricular he- morrhage had swallowing problems with failure to thrive. CT showed an enlarging IV ventricle. Ventriculoscopy re- vealed a thin membrane over the aqueductal entrance which was perforated with the end of a 1.2-mm fiberoptic scope. The scope was then navigated through the aqueduct into the IV ventricle. No stent was left in the aqueduct. The patient awoke with dysconjugate eye movements. These resolved spontaneously within 1 week. The patient re- mained asymptomatic despite the IV ventricle's remaining large on postoperative imaging.

Case 11

A 54-year-old lady presented with visual deterioration. Neuroimaging revealed a large pituitary macroadenoma with massive suprasellar and infrasellar extension. She un- derwent a pterional craniotomy and endoscopic trans-

Although most complications are unavoidable, we can limit their frequency by learning from the experience of others. All too often, the reputation of a new technique falls into disrepute from its injudicious use by inexperienced, though well-intentioned practitioners. Neuroendoscopy should be considered a safe technique. Complication rates vary with the condition being addressed, but are mostly equivalent to or lower than those associated with alterna- tive methods [6, 7, 14, 17].

Endoscopic III ventriculostomy, although safer than percutanous and open techniques [5, 10, 13], has a higher and more significant operative complication rate than ven- triculoperitoneal shunts. However, when successful, it is a once-only procedure, unlike a shunt, which often requires several revisions within a lifetime, each time subjecting the patient to further operative risk and long-term seque- lae such as infection. We concede that hypothalamic da- mage may be limited by employing more precise methods of puncturing the III ventricular floor, such as laser and balloon dissection - techniques not practiced by the first author. Nevertheless, it appears that risk to the hypothala- mus exists whatever the method used [5, 10, 14, 16]. Cer- tainly, the authors recommend a selection of rigid endo- scopes to prevent scope-to-foraminal disproportion, as III ventricular width is frequently less than 5 mm.

Aqueductal plasty had the highest rate of significant complication in this study. This has not been reported be- fore [9], but is definitely recognized among experienced neuroendoscopists. It is presumed that the tectal plate or dorsal wall of the aqueduct is acutely sensitive to pressure, although upward gaze may be preserved (case 10). Modi- fication of this procedure may diminish the risk but may also compromise the patency of the aqueduct. Fortunately, the long-term outcome of both of the patients in this series undergoing this procedure (cases 9, t0) was good and they did not require extended hospitalization. Generally, when complications occurred, hospitalization was prolonged be- cause of the patient's clinical condition or the surgeon's caution.

Clinically significant complications of neuroendoscopy were rare (7%). We contend that they will occur even with adequate training and experience. Clinically insignificant complications, in contrast, were common (13%) and ap- peared to diminish with experience. These problems,

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which were more unique to endoscopy, may be avoided by observ ing some impor tan t pr inciples :

1. Or ient the scope and v ideo image before enter ing the cranium.

2. Use i r r iga t ion caut ious ly and l ibe ra l ly to improve the view and ident i fy ana tomica l structures.

3. Do not wie ld r ig id scopes in large arcs that may damage the pa r enchyma and structures that have been passed and are out of view, e.g., b r idg ing vessels , fornices, cranial ner- ves, etc.

4. Be aware that laser and monopo la r coagula t ion can ele- vate CSF tempera tures to dangerous levels .

5. Do not be afraid to abandon an endoscop ic p rocedure in favor of a more invas ive but fami l ia r technique i f the ana- tomy is unusual or the s i tuat ion compl ica ted .

Conclusion

Neuroendoscopy , when used appropr ia te ly and by t ra ined pract i t ioners , is safe. Compl ica t ions can be reduced by ex- per ience , a l though most compl ica t ions unique to endos- copy wil l not resul t in c l in ica l ly s ignif icant problems. The steep learning curve may be reduced by fo l lowing the few impor tant pr inc ip les out l ined above.

References

1. Auer LM, Deinsberger W, Niederkorn K (1989) Endoscopic surgery versus medical treatment for spontaneous intracerebral hematoma: a randomized study. J Neurosurg 70:530-535

2. Fukushima T (1978) Endoscopic biop- sy of intraventricle tumors with the use of a ventriculofiberscope. Neurosur- gery 2:110

3. Griffith HB (1986) Endoneurosurgery: endoscopic intracranial surgery. In: Sy- mon L (ed) Advances and technical standards in neurosurgery, vol 14. Springer, New York Berlin Heidelberg, pp 2 - 24

4. Handler MH, Abbott R, Lee M (1994) A near fatal complication of endoscop- ic third ventriculostomy: case report. Neurosurgery 35:525-528

5. Hirsch JF (1982) Percutaneous ventri- culocisternostomies in noncommuni- cating hydrocephalus. Monogr Neurol Sci 8:170-178

6. Hoffman HJ (1976) The advantages of percutaneous third ventriculostomy over other forms of surgical treatment for infantile obstructive hydrocepha- lus. In: Morley TP (ed) Current contro- versies in neurosurgery. Sannders, Philadelphia, pp 691-703

7. Lewis AL, Crone KR, Taha JM (1994) Surgical resection of third ventricle colloid cysts: preliminary results com- paring transcallosal microsurgery with endoscopy. J Nenrosurg 81: 174-178

8. Manwaring KH (1992) Endoscope- guided placement of the ventriculope- ritoneal shunt. In: Manwaring KH, Crone KR (eds) Neuroendoscopy. Lie- bert, New York, pp 29-40

9. Oka K, Yamamoto M, Ikeda K, Tomo- raga M (1993) Flexible endoneurosur- gical therapy for aqueduct stenosis. Neurosurgery 33:236-243

10. Pierre-Kahn A, Renier D, Bombois D (1975) Place de la ventriculocisternos- tomie dans la traitement des hydro- cephalies non communicantes. Neuro- chirurgie 21:557-569

11. Pierre-Kahn A, Capelle L, Sainte-Rose C, Renier D, Hoppe-Hirsch E, Hirsch JF (1990) Treatment of suprasellar arachnoid cysts by percutaneous trans- frontal ventriculocystostmy. Apropos of 17 cases. Neurochirurgie 36:370-377

12. Pool JL (1938) Myeloscopy: intraspi- nal endoscopy. Surg Clin North Am 37: 1401-1402

13. Stookey B, Scarff J (1936) Occlusion of the aqueduct of Sylvius by neoplas- tic and non-neoplastic processes with a rational surgical treatment for relief of the resultant hydrocephalus. Bull Neu- rol Inst NY 5:348-377

14. Teo C, Jones RFC, Stening WA, Kwok BCT (1991) Neuroendoscopic third ventriculostomy. In: Matsumoto T (ed) Hydrocephalus: pathogenesis and man- agement. Springer, Tokyo, pp 672-683

15. Teo C, Pihoker K, Ratcliffe S, Boop FA (1994) Anatomical and physiologi~ cal considerations of third ventriculos- tomy (abstract). Child's Nerv Syst 10:481

16. Vries J (1978) An endoscopic tech- nique for third ventriculostomy. Surg Neurol 9: 165-168

17. Walker ML, Petronio J, Carey CM (1994) Ventriculoscopy. In: Cheek WR (ed) Pediatric neurosurgery: surgery of the developing nervous system. Saun- ders, Philadelphia, pp 572-581

Endoscop ic neurosurgery has grown by leaps and bounds and is now being used for a wide var ie ty of neu- rosurgica l condi t ions . The authors have shown us that this is not a s im- p le p rocedure and that compl ica t ions can occur f rom endoscop ic neurosur-

gical procedures . The most impor- tant factor is the learning curve which the neurosurgeon must go through in order to become a compe- tent endoscopic neurosurgeon. We are grateful to the authors for point- ing out the compl ica t ions of endo-

scopic neurosurgery and making the neurosurgica l wor ld aware that en- doscopic neurosurgery is not a s im- ple procedure .

Haro ld J. Hoffman, Toronto