Microscopic Endonasal Surgeryof the Paranasal Sinusesand the Parasellar RegionRonald G. Amedee, MD; Wolf J. Mann, MD; Joachim M. Gilsbach, MD

\s=b\The anatomic principles and opera-tive techniques currently applied to func-tional endoscopic endonasal surgery haveallowed for significant refinements in an-

other approach to regional pathology thatuses the operating microscope, newly de-signed sinus instruments, and a self-re-taining nasal speculum system. The mainbenefits of this method are the superbwidefield stereoscopic vision and the dis-tinct freedom to work bimanually. Addi-tionally, direct bipolar cautery of bleedersis afforded while use of the observer tubeor video allows for excellent teaching. Theprecise nature of this surgery affords lessfear of serious complications in the treat-ment of periorbital, paranasal sinus, andparasellar diseases. We describe techni-cal aspects of the surgery and associatedcomplications in 219 patients treated from1984 to 1987.

(Arch Otolaryngol Head Neck Surg.1989;115:1103-1106)

Microscopie endonasal surgery(MES) of the paranasal sinuses

has been performed in adults since thelate 1950s, and was first reported forsinus surgery in children in 1976.1-2 Itwas initially used as a technique forcreating an antrostomy, and recentlyhas been used for more difficult intra-nasal ethmoidectomy and transeth-moidosphenoidectomy.34 The develop¬ment of special self-retaining nasalspeculum systems have greatly aidedthis form of surgery in both adults andchildren with a variety of regional ab¬normalities, including chronic sinusinfection, benign polyps, orbital ab-

Accepted for publication March 3, 1989.From the Departments of Otolaryngology (Drs

Amedee and Mann) and Neurosurgery (Dr Gils-bach), University of Freiburg (West Germany)Medical School. Dr Amedee is now with theTulane University Medical Center, New Orleans,La.Presented at the fourth International Congress

of the Skull Base Study Group, Hannover, WestGermany, June 3-6, 1988.Reprint requests to Department of Otolaryn-

gology\p=n-\Headand Neck Surgery, Tulane Univer-sity Medical Center, 1430 Tulane Ave, New Or-leans, LA 70112-2699 (Dr Amedee).

scess, and tumors of the orbit, para¬sellar, and hypophyseal regions. Thespeculum holder is attached to the op¬erating table enabling the surgeon towork bimanually. The surgeon maystand or be seated at the patient's sidewith the operating hands resting on

the patient, thus affording excellentcontrol of the instruments. Binocular,stereoscopic vision with excellent illu¬mination creates additional precisionand control in delicate ethmoid andsphenoid sinus surgery. The Zeiss op¬erating microscope with a 300-mm ob¬jective lens and halogen illuminationis recommended, while an observerarm or video camera mounted on themicroscope has provided an outstand¬ing opportunity for resident teaching(Figs 1 through 3).Preoperative shrinkage of the nasal

mucous membranes is done with topi¬cal vasoconstrictors; however, injec¬tions with local anesthetics plus epi-nephrine have proved unnecessary.Microscopic endonasal surgery shouldbe performed using hypotensive anes¬

thesia (systolic blood pressure, 70 to 90mm Hg) to decrease intraoperativebleeding, and the patient should beplaced in a semi-Fowler's position en¬

abling blood and mucus to drain fromthe skull base and away from theoperative field. The eyelids are left un¬covered and should always remain inthe peripheral field of vision. Bilateralsurgery attempted at the same sittingis not contraindicated and is usuallycompleted within 60 to 90 minutes.This technique was used with local an¬esthesia in two cases, but it was foundunacceptable due to the constant pres¬sure exerted by the nasal speculum.The complex anatomy of the para-

nasal sinuses, the parasellar region,and the surrounding vital structureshas become more familiar to our spe¬cialty with the advent of endoscopieendonasal sinus surgery.58 Currently,

fewer Caldwell-Luc and other externalapproaches are deemed necessary, ex¬cept in cases where malignancies are

suspected.4 The diagnosis of chronicsinusitis is made when obstruction ofthe ostia occurs due to persistent dis¬ease in the region of the ostia and bullaethmoidalis with irreversible mucosalthickening evident by radiologie eval¬uation. High-resolution axial andcoronal computed tomographic scans

offer a precise way to evaluate thepresence of sinus disease and furtheraid in determining when surgery isindicated.9Many patientswith chronic sinusitis

and/or polyposis will require specificallergy testing and treatment. We ad¬vocate that definitive surgery, whenindicated, be performed first.10 In theevent a rare postoperative infectiondevelops, allergy testing should be de¬ferred until all signs of infection are

thoroughly cleared to avoid an inaccu¬rate response. Postoperative antibiot¬ics were routinely used in the initial150 cases, while in the remaining casesnone were given unless a purulentsinusitis or abscess was found at thetime of surgery. The use of postopera¬tive antibiotics in MES for chronic si¬nusitis (with or without polyposis) isthe source of an ongoing study in our

clinic and final results will be availablewithin several months.

ETHMOIDAL AND SPHENOIDALSINUS SURGERY

The middle turbinate is displacedmedially under microscopic vision, andnext the self-retaining speculum is in¬troduced into the nose and positionedwithin the proximal middle meatus,supporting the middle turbinate to¬ward the septum (Fig 4). An infundib-ulotomy is performed with a 30° eth¬moid forceps by first resecting theuncinate process and then by enteringthe larger anterior ethmoidal cells.

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Fig 1.—

Set of useful microscopic endonasal instruments.

Fig 2.—Self-retaining speculum system inserted into the nose and fixedto the operating table.

Fig 3.—Bimanual microscopic endonasal surgery with opportunity forresident teaching.

Fig 4.—Microscopic view through the speculum demonstrating the mid¬dle turbinate (MT) and the middle meatus (MM; arrow).

Fig 5.—Postoperative view of epithelialized ethmoidal cavity 2 years af¬ter surgery. FR indicates frontal recess; MO, maxillary ostium; and ER,ethmoidal roof.

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The bony labyrinth (including mucosa,polyps, and/or secretions) is removedwith either a straight ethmoid forcepsor a Caspar bone forceps. The middleturbinate is used to guide the dissec¬tion directly posterior until the ante¬rior wall of the sphenoid sinus is ex¬

posed and the roof of the ethmoid sinusis identified. Resection then followsthe ethmoidal roof from posterior toanterior, and a curved 30° curet isgently used to expose the entire roofand lateral sinus wall, which repre¬sents the lamina papyracea of the or¬

bit. This lateral wall may be opened,when indicated, to allow for intranasaldrainage of an orbital abscess. Bleed¬ing is usually not a problem and is ad¬equately controlled with selective bi¬polar cautery using long and delicateforceps.Dissection should not be performed

medial to the superior attachment ofthe middle turbinate, since the bone ofthe cribriform plate is extremely thinand delicate, and injury to this regionis likely to result in cerebrospinal fluidrhinorrhea. During the operation theanterior portion of the middle tur¬binate is carefully preserved as a use¬ful anatomic landmark in the eventsecondary procedures are indicated.The posterior half of the middle tur¬binate is routinely resected, since, inearlier cases, we found that it ob¬structed proper cleansing of the poste¬rior cavity, especially in the region ofthe sphenoidotomy. In addition to re¬

secting this portion of the middle tur¬binate, we cauterize the posterior endof the inferior turbinate. In the eventa concha bullosa is present we recom¬

mend resection of the lateral half ofthe remaining middle turbinate withthe associated air cell(s).The incidence of sphenoidal sinus

disease is greatly reduced when com¬

pared with ethmoidal disease. In theevent sphenoidotomy is indicatedbased on preoperative radiologie eval¬uation and intraoperative findings,this may be accomplished by gentlypushing through the anterior sphenoidwall with the straight ethmoid forcepsor a curet. This opening is then en¬

larged with a fine 30° ethmoid forcepsor a curet. The diseased contents of thesinus must be cautiously removed,since in 13% of our cases the lateralbony wall of the sinus was partially

dehiscent and careless curettage couldhave resulted in injury to the opticnerve or the internal carotid artery.We recommend delicate palpation ofthe lateral wall with a forceps or suc¬

tion prior to removal of the sinus con¬tents. The sphenoid sinus has been en¬tered by this transethmoidal approachand by access through its natural ostiain the sphenoethmoidal recess to re¬

pair traumatic defects of the ethmoi¬dal and sphenoidal roof with concom¬itant cerebrospinal fluid leakage. Thedurai dehiscence is repaired using fas¬cia obtained from the anterior layer ofthe rectus abdominis sheath and thesinus is subsequently packed with al¬ternating layers of abdominal fat andpressed collagen sheets, all held inplace by fibrin glue.The approach for hypophysectomy

is usually lateral to the middle tur¬binate by accessing the sphenoid sinusvia posterior ethmoidal air cells. Sim¬ilar exposure may be used to performa biopsy and/or to resect parasellartumors, provided the dura is intact andthe extent of disease is limited. Thebony skull base has been resected wheninvaded by tumor, but only if it ap¬pears that the tumor is respecting thedura. For more extensive disease withdurai invasion, neurosurgical evalua¬tion is obtained and, if deemed resect-able, a bicoronal or pterional approachis used. Microscopic endonasal surgeryis by no means an acceptable approachto extensive tumors that may requiremore radical resection, but serves as asuitable means to obtain a biopsy spec¬imen that may prove a valuable ad¬junct in patient management.FRONTAL AND MAXILLARY SINUS

SURGERYExternal approaches to the frontal

sinus are reserved for traumatic de¬fects, tumors, and bony obliteration ofthe nasofrontal ducts. The frontal re¬cess is usually identified in the anteriorportion of the roof of the ethmoid, andoccasionally ethmoidal polyps hinderdirect visualization of this opening.These polyps represent the most com¬mon cause of frontal sinus obstructionin this study, a situation readily im¬proved by complete polypectomy. Inrare cases, when preoperative evalua¬tion reveals an opacified sinus but noethmoidal polyps are found intraoper-

atively, a check for patency of the ductis made using a Ritter bougie or a 70°backward-cutting curet. If the preop¬erative computed tomographic scan

reveals a normal frontal sinus and thepatient is asymptomatic, then thisportion of the surgery may be omitted.Similarly, problems within the maxil¬lary sinus most commonly result fromobstruction of the natural ostium.Once this obstruction is removed, thenatural ostium is gently probed to seeif the 70° curet may be introduced. Ifthis maneuver is not possible, the os¬tium is enlarged with a backward-cut¬ting antral punch, avoiding the regionof the nasolacrimal duct.Visualization of areas requiring an¬

gular views, such as the maxillary an¬

trum and frontal recess, are attemptedinitially by moving the patient's headand by looking directly into these re¬

gions. In 35% of our cases this viewwas achievable. When direct visualiza¬tion is not obtained by positionchanges of the head, angled 30° and70°, telescopes are recommended.

POSTOPERATIVE CAREA continuous nasal tamponade con¬

sisting of 2-cm-wide surgical gauzeimpregnated with sulfur gel is looselypacked into the sphenoidal and eth¬moidal sinus cavities. Half of the en¬

tire tamponade is removed from eachside 24 hours after surgery, and theportion remaining on the second post¬operative day. Gentle suction of thecavities, including the internal nasalairways, is then performed and thepatient is instructed to begin nasal ir¬rigations three times a day with luke¬warm saltwater. Additionally, a de¬congestant nasal spray followed by a

topical nasal steroid inhaler are bothapplied three times a day. Finally, amenthol nasal salve is applied to thenostrils as needed to help prevent post¬operative drying and crusting. Itshould be emphasized that careful dé-bridement of the cavities must be per¬formed at 2- to 3-day intervals duringthe first postoperative week. The pre¬viously described regimen of irriga¬tions and sprays has significantly im¬proved patient comfort and reducedthe occurrence of secondary infections.The steroid nasal inhaler is continuedafter the first week for 3 to 12 monthsto reduce nasal mucosal edema and to

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Indications for Microscopic EndonasalSurgery in 219 Patients

No. ofCases

(N = 219)Choanal atresia 2Chronic sinusitis and/or

polyposis nasi 165Maxillary sinus mucocele 5Concha bullosa 4Traumatic sphenoid;

cerebrospinal fluid rhlnorrhea 19Orbital abscess/decompression 7Sphenoidal / ethmoidal

tumor biopsy 10Inverted papilloma

lateral nasal wall 1Hypophysectomy 6

prevent early polypoid changes, whilethe irrigations and decongestant sprayare omitted. Occasionally the gel iscontinued for a longer period in an ef¬fort to enhance nasal moisturization.Allergy testing and immunotherapy,when indicated, are essential in pre¬venting the early and undesirable re¬currence of intranasal polyps (Fig 5).

COMMENTThe most common indication for

MES in this series was chronic sinusi¬tis frequently complicated by polypo¬sis nasi that accounted for 75% of allcases (Table). For each of these indi¬cations the results were satisfying notonly to the surgeon, but also to uni¬formly grateful patients. All of thesesituations were sucessfully handledduring the initial MES, including thebiopsy of 10 paranasal sinus tumorsand the permanent control of 19 casesof traumatic ethmoidal and/or sphe¬noidal cerebrospinal fluid rhinorrhea.No external approaches or secondaryMES procedures were necessary tocomplete the diagnosis or treatment inthe study group.The patients with chronic sinusitis

and polyposis are predictably well con¬trolled with this procedure and expe¬rience a dramatic improvement intheir overall condition and nasal res¬piration. This subgroup of 165 patientshad a mean postoperative follow-uptime of more than 2 years (830 days).Recurrent or persistent polyps wereobserved in 21 patients (13%), andwere easily removed in the clinic, withthe patient receiving topical anesthe¬sia, during the patient's postoperative

examination. Recurrent sinusitis inthis group of patients has not been ob¬served following MES.The rate of severe complications was

markedly less with MES comparedwith the traditional external ap¬proaches. Bleeding that requiredtransfusion, visual disturbances as aresult of nerve or muscle injury, cere¬brospinal fluid fistula with abscess or

meningitis, alterations of facial ordental sensation, or impairment of ol¬faction are all theoretically possible,but have not occurred to date. Septalperforations have not been attributedto usage of the self-retaining speculumsystem or to septoplasty performed inconjunction with MES. The most com¬mon complications in the 219 patientsreported have been limited to minorepistaxis occurring in 44 (20% ), head¬ache in 37 (17% ), and mild to moderatemidfacial pain with swelling observedin 13 (6%). The epistaxis was con¬trolled without further packing, andthe pain with swelling is improvedtremendously when the intranasalpacks are completely removed. Thespecial equipment required for MES,including a microscope, telescopes, andgeneral anesthesia, should be men¬tioned as potential disadvantages ofthis technique.Endoscopie endonasal procedures

are used in our clinic in patients whorequire limited resections for diseasein the anterior ethmoidal cells, or inevaluating and eradicating diseaseconfined to the maxillary sinuses. Thefrontal recess and frontal sinus mu¬cosa are best visualized with the 30°and 70° endoscopes, and with perior¬bital cellulitis the endoscopes are usedexclusively. Microscopic visualizationis reserved for the patient with bilat¬eral, massive polyposis involving al¬most all of the paranasal sinus systemwith resultant total or near-total nasalobstruction. Bleeding encounteredfrom the anterior and posterior eth¬moidal arteries is easily controlledwith the microscopic technique. Thefield of vision afforded allows for bi-manual control of instruments and se¬lective bipolar cautery of vessels.Improved diagnostic techniques, es¬

pecially high-resolution computed to¬mographic scanning, now enable pre¬cise localization of paranasal sinus andparasellar diseases. Major advances in

operative instrumentation and a bet¬ter understanding of the mucociliaryclearance patterns have led to thisconcept of MES. This technique resultsin decreased morbidity, allows preser¬vation of normal tissue, and, in themajority of cases, avoids the necessityfor external procedures.Microscopic endonasal surgery us¬

ing newly designed instruments withthe self-retaining speculum system al¬lows for bimanual surgery with excel¬lent control of instruments, while thebinocular vision ensures excellent sur¬gical precision and illumination. Mi¬croscopic endonasal surgery of theparanasal sinuses and parasellar re¬

gion affords adequate resection or bi¬opsy of diseased tissues with less fearof serious complications. Troublesomebleeding is easily controlled by selec¬tive bipolar cautery, hypotensive gen¬eral anesthesia, and use of the semi-Fowler's position that allows bloodand mucus to flow away from the op¬erative field. The use of an observerarm or video camera mounted on themicroscope provides an outstandingopportunity for resident teaching.This study was supported by the German Aca¬

demic Exchange Service (Bonn, West Germany)grant 315-402-021-8.

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